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Hettiarachchi, Samanthika Ruvinie. "Exciplex Tuning and Optical Memory Studies for Dicyanoargentate(1) and Dicyanoaurate(1) Ions Doped in Potassium Chloride Crystals Extension to Mixed Metal Gold and Silver Systems." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/HettiarachchiSR2002.pdf.
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Tadayyon, Abdolsamad. "Modeling, control and measurement in continuous potassium chloride crystallizers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0030/NQ63928.pdf.
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Imhof, Monica Y. "Salt substitution : the inhibition of potassium chloride bitter aftertaste." Thesis, Oxford Brookes University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363568.
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Lee, H. C. "Phospho-dependent modulation of potassium chloride co-transporter KCC2." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/17998/.
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The neuronal-specific potassium chloride co-transporter 2, KCC2, is a major chloride extruder in brain. The expression of KCC2 during neuronal development is fundamental to the switch of GABAergic response from excitatory to inhibitory. Malfunction of KCC2 can cause impairment of chloride homeostasis in neurons and is implicated in neurological disorders such as epilepsy. To date the role of protein phosphorylation in the regulation of KCC2 remains elusive. In this thesis, direct phosphorylation of KCC2 by PKC and Src tyrosine kinase was shown in vitro and in cultured neurons using the radioactive isotope 32P. Single mutation of serine residue at position 940 in the intracellular domain of KCC2 (Ser940) to alanine (S940A) blocked the phosphorylation of KCC2 under PKC activation. However, tyrosine phosphorylation of KCC2 was shown to not affect Tyr1087, the putative tyrosine kinase phosphorylation site. To better understand phosphorylation of KCC2 at Ser940, a phospho-specific antibody against this residue - namely p-S940 - was developed. Interestingly, agents inhibiting PKC and phosphatases altered signal of p-S940, indicating involvement of PKC, phosphatase-1 (PP1) and phosphatase-2A (PP2A) in the regulation of Ser940 phosphorylation. In an in vitro method using p-S940, it was shown that PP1 and PP2A dephosphorylated KCC2.
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Lu, Ying. "Effects of sodium chloride salting and substitution with potassium chloride on whey expulsion of cheese." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1285.
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The rate and extent of syneresis (whey expulsion) strongly affects cheese composition and quality. During salting, curd syneresis is influenced by the combined effect of both osmotic pressure and protein hydration. Our objective is to examine how cheese composition and whey expulsion are influenced by dry salting curd at various intervals, levels, applications, and potassium chloride (KCl) substitution, or change in calcium or sodium level in test solution (i.e., whey-brine). Four sets of unsalted fresh Cheddar curds were salted with different methods, with at least 3 replicates of each set on separate days. Set A was salted with 30 g/kg NaCl over 3 applications, either 5 or 10 min apart. Set B was salted with 30, 25, and 20 g/kg NaCl over 3 applications 5 min apart. Set C was salted with 20 g/kg NaCl using 1, 2, or 3 applications. Set D received salt consisting of a 2:1 molar ratio of NaCl and KCl over 3 applications 5 min apart. Whey was collected every 5 or 10 min until 30 or 40 min after the start of salting and subsequently pressed for 3 h. Using 10-min intervals delayed whey syneresis but after pressing there was no significant influence on final cheese composition. Decreasing salt levels significantly reduced the amount of whey expelled prior to pressing and resulted in cheeses with higher moisture and slightly lower pH. Adding salt over different applications did not significantly affect cheese composition. Partial substitution with KCl did not affect the amount of whey expelled or cheese moisture composition. Salted milled Cheddar cheese curd was immersed at 22°C for 6 or 18 h in test solution, with the addition of 1, 5, 10, or 20 g/L calcium, and 15 g/L salt. After immersion, curd weight change, moisture, pH, sodium, serum calcium and total calcium levels were measured. When calcium levels in solution increased, curd moisture, pH, and weight gain decreased while serum and total calcium levels increased significantly. Similarly, unsalted milled Cheddar cheese curds were immersed at 22°C for 6 h in test solution with 30, 60, 90, or 120 g/L salt in addition to 6 g/L calcium. The salt level in solution was inversely proportional with weight change, moisture, and salt level of curd.
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Goutierre, Marie. "Contribution of the potassium / chloride cotransporter KCC2 to hippocampal rhythmopathy." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS600.
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Dans le système nerveux central, la transmission inhibitrice est principalement assurée par le relargage du neurotransmetteur GABA dans la fente synaptique. La fixation du GABA sur les récepteurs GABAA induit en effet un flux entrant d’ions chlorure, résultant en une hyperpolarisation du neurone. Le maintien d’une faible concentration intraneuronale en chlore est donc essentielle à l’action inhibitrice du GABA. Dans les neurones matures, cette fonction est principalement réalisée grâce à l’activité du transporteur potassium – chlore KCC2 qui exporte en permanence les ions chlorures. Dans de nombreuses pathologies neurologiques, telles que l’épilepsie, le syndrome de Rett ou encore les douleurs neuropathiques, on observe une diminution de l’expression de KCC2. Cela conduit à une élévation du niveau de chlore intraneuronal et à une altération de la transmission GABAergique. Cet effet est supposé être à la base de nombre des symptômes observés dans les pathologies citées précédemment. Cependant, KCC2 est également fortement exprimé à proximité des synapses glutamatergiques. Sa présence influence ainsi l’efficacité de la transmission excitatrice et est nécessaire à l’expression de la potentialisation à long terme des synapses. Ces fonctions inattendues de KCC2 aux synapses excitatrice ne reposent pas sur sa fonction de transport de chlore mais plutôt sur ses interactions avec diverses protéines. Ainsi, le transporteur KCC2 possède de multiple fonctions et régule différemment les transmissions excitatrice et inhibitrice. Prédire l’effet de la perte du transporteur sur l’activité globale d’un réseau neuronal est donc compliqué. Durant ma thèse, j’ai caractérisé les effets de la suppression de KCC2 dans les cellules en grains du gyrus denté sur leurs propriétés cellulaires, synaptiques et sur l’activité du réseau hippocampique. De façon inattendue, j’ai montré que la perte de KCC2 ne s’accompagnait pas de modifications majeures de la transmission inhibitrice. En revanche, j’ai mis en évidence un nouveau mécanisme indépendant du transport de chlore par lequel KCC2 contrôle l’excitabilité des neurones et la rythmogénèse hippocampique à travers son interaction avec le canal potassique Task-3. Mes résultats prédisent que les déficits associés à une perte de KCC2 pourraient être en partie expliqués par cet effet sur l’excitabilité. Ils suggèrent également que Task-3 pourrait constituer une nouvelle cible thérapeutique dans le traitement de ces pathologiesIn the CNS, synaptic release of GABA neurotransmitter is mainly responsible for fast inhibitory transmission. This is mediated by chloride flow through GABAARs. Hence, tight control of chloride homeostasis is critical for maintenance of the efficacy of GABAergic transmission. In mature neurons, this is primarily achieved by the activity of the potassium – chloride transporter KCC2 which extrudes chloride from the cells. Expression of KCC2 is compromised in numerous neurological disorders including epilepsy, Rett syndrome or neuropathic pain. Subsequent alterations of GABAergic signaling through accumulation of intraneuronal chloride are thought to underlie many of the pathological symptoms observed in these conditions. However, KCC2 is also highly expressed in the vicinity of glutamatergic synapses where it plays a major role in controling the efficacy of glutamatergic transmission and gates long-term potentiation of excitatory synapses. Remarkably, these functions did not depend on chloride transport but rather on KCC2 interaction with several protein partners. Hence, KCC2 can be classified as a moonlightning protein with multiple functions at excitatory and inhibitory synapses. This complicates predictions of the overall effect of its suppression on a neuronal network. During my PhD, I characterized the effects of KCC2 downregulation in dentate granule cells at the cellular, synaptic and network levels. Unexpectedly, lack of KCC2 did not impact steady-state GABAergic transmission. In contrast, my work shed light on a novel critical role of KCC2 in controling neuronal excitability through its interaction with the leak-potassium channel Task-3. This in turn alters hippocampal rhythmogenesis. My results thus described a novel mechanism through which KCC2 influence neuronal activity indepently of its transport function. They predict that deficits associated with KCC2 downregulation may be at least partly explained by regulation of cell excitability and point to Task-3 as a new potential therapeutic target in the treatment of these pathologies
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MacKenzie, Georgina Louise. "Control of membrane excitability by potassium and chloride leak conductances." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/7038.
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The permeability of the neuronal membrane to different ions determines both resting membrane potential (RMP) and input conductance. These parameters determine the cells response to synaptic input. In this thesis I have examined how the molecular properties of potassium and chloride ion channels can influence neuronal excitability in ways that have not previously been considered. For example, two‐pore domain potassium (K2P) channels open at rest to generate a persistent potassium ion efflux. In addition to its accepted role in setting the RMP, I have tested the hypothesis that this conductance is sufficient to repolarise the membrane during an action potential (AP) in the absence of voltage‐dependent potassium channels (Kv). We tested this prediction using heterologous expression of TASK3 or TREK1 K2P channels combined with conductance injection to simulate the presence of a voltage‐gated sodium conductance. These experiments demonstrated that K2P channels are sufficient to support APs during short and prolonged depolarising current pulses. The membranes permeability to chloride ions can also be affected by extrasynaptic GABAA receptors containing the delta subunit (δ‐GABAARs) that produce a tonic conductance due to their high apparent affinity for GABA. The anaesthetics Propofol and THIP are both believed to alter neuronal excitability by enhancing this persistent chloride flux. We have examined how this anaesthetic action is affected by the steady‐state ambient GABA concentrations that are believed to exist in vivo. Surprisingly, the anaesthetic enhancement of δ‐GABAARs is lost at low ambient GABA concentrations. Therefore, I would suggest that the anaesthetic potency of these drugs is affected by the resting ambient GABA concentration in a manner that has not previously been appreciated. In the current Thesis I have examined the molecular and pharmacological properties of two very different ion channel families that both generate a leak conductance, and I will present models that link the behaviour of these ion channels to their ability to modulate neuronal excitability.
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Cook, John William. "The effect of foliar applied fertilisers on leaf diseases of cereals." Thesis, Open University, 1998. http://oro.open.ac.uk/57740/.
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The effects of foliar applied urea and potassium chloride on the severity of leaf diseases of cereals were investigated in the laboratory, glasshouse and field between 1992 and 1995. Field studies with urea gave inconsistent results with respect to severity of Erysiphe graminis and consistently increased the leaf area affected by Septaria tritici. However, potassium chloride applied as a foliar spray consistently decreased the leaf area of wheat affected by E. graminis and S. trifid compared with equivalent applications of soil applied fertiliser. Disease control was achieved at early stem extension and after flag leaf emergence but yield responses were not detected. Laboratory investigations were undertaken to determine the mechanism by which foliar applied potassium chloride reduced the leaf area affected by E. graminis. The timing of application, within seven days pre or post inoculation, had no consistent effect on the efficacy of the fertiliser. Investigations using polyethylene glycol as a control showed that the percentage leaf area affected declined linearly as the osmotic potential of the solutions were increased. Light microscopy revealed that the germination of spores in solution and on treated leaves was reduced as the osmotic potential of the solutions were increased. Spores which did germinate developed normally but those on leaves treated with solutions of high osmotic potential rarely formed haustoria. This suggested a second mechanism acting inside the leaf. Multiple regression analysis of experimental data indicated that the inhibition of spore germination was the major response reducing the area of the leaf affected. Although the data were not conclusive it appeared that the increase in leaf water potential, following the foliar application of potassium chloride, was involved in the control of E. graminis.
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Reynolds, Annie 1978. "Over-expression of the potassium-chloride co-transporter KCC2 in developing zebrafish." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98778.
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In embryonic neurons, the intracellular chloride concentration is elevated, making GABA and glycine depolarizing. Later in development, coincident with neuronal maturation, the extruding potassium-chloride co-transporter KCC2 is expressed. It reverses the chloride gradient, rendering it hyperpolarizing. Early depolarization is assumed to play trophic roles during nervous system development. I thus decided to investigate the effects of the depolarizing chloride gradient on development in vivo in the zebrafish embryo. I first determined the temporal pattern of KCC2 expression in zebrafish and found it was absent in the embryo. I then over-expressed wild-type, gain-of-function and loss-of-function variants of human KCC2, using GFP-tagged constructs for detection purposes. Over-expression of functional hKCC2 perturbed the morphology and motor behaviours of the embryos. At the cellular level, KCC2 impaired axonal growth and affected the neuronal populations in the brain, hindbrain and spinal cord. This suggests the depolarizing effects of glycine are critical for neurogenesis.
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Mann, Ruth Louise. "Suppression of Septoria tritici by foliar applied potassium chloride on winter wheat." Thesis, University of Wolverhampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322183.
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The effect of foliar applied potassium chloride on Septoria tritici on winter wheat was quantified and possible modes of action investigated by in vitro, glasshouse, controlled environment and field experiments between 1996 and 1999. In vitro experiments showed that as the concentration of potassium chloride increased, mycelial growth and germination of conidia decreased (EO sos of 1.36M and 0.7M, respectively). One glasshouse and two field experiments showed a significant reduction in the leaf area affected by S. trttict after foliar application of potassium chloride compared to untreated controls. In general, application of potassium chloride reduced the leaf area affected by S. tritici by 20 -.40%. However, a significant yield increase was not observed. Potassium chloride applied to the lower leaves of winter wheat did not confer systemic acquired resistance against S. tritici on the upper leaves. Inhibition of conidial germination, on leaf surfaces by potassium chloride was observed. Similar inhibition was observed when polyethylene glycol, an inert osmoticum, was applied at the same calculated osmotic potential. During field experiments there was no significant difference in the leaf area affected by S. tritici in plots treated with potassium chloride or polyethylene glycol, although both significantly reduced the leaf area affected compared to untreated control plots. Therefore, the principal mode of action of potassium chloride was proposed to be as a result of adverse osmotic conditions caused by the salt on leaf surfaces. However, the addition of a range of adjuvants to potassium chloride did not increase the efficacy of S. tritici control in glasshouse studies. The results from this study show that potassium chloride, when applied to foliage of winter wheat can reduce the leaf area affected by S. tritici and it is proposed that this reduction was by adverse osmotic conditions caused by the salt on leaf surfaces.
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Joo, Nam Soo. "Regulation of duodenal ion transport by uroguanylin and cloning of murine intestinal CIC-2 chloride channel." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9924893.
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Leeuw, Kelebogile Ancient. "The influence of potassium carbonate and potassium chloride during heat treatment of an inertinite-rich bituminous char / Kelebogile Ancient Leeuw." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8759.
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Thermogravimetry, coupled with a mass spectrometer (TG-MS) was used to investigate
the catalytic effect potassium carbonate (K2CO3) and potassium chloride (KCl), on the char conversion and the product gas composition of chars derived from a South African inertinite-rich bituminous coal. Sequential leaching of the coal with HCl-HF-HCl was performed to reduce the mineral matter present in the coal. This was done in order to reduce possible undesirable interactions between the minerals and inorganic compounds in the coal during heat treatments. The leaching process substantially reduced the ash content from 21.5% to less than 3%.
K2CO3 and KCl [0.5, 1, 3, 5 K-wt %] were loaded to the demineralized coal, raw coal and
demineralized coal with added mineral mixture prior to charring. The mineral mixture was made up of kaolinite, quartz, pyrite, siderite, calcite, anastase and hydromagnesite. The ‘doped’ coal samples were then subjected to heat treatments in a CO2 atmosphere up to 1200 °C. The results obtained showed that both K2CO3 and KCl exhibit a catalytic effect on the char conversion during heat treatments in CO2 atmosphere and the char conversion was increased with increasing loadings up to 5 K-wt% of K2CO3 and KCl. The temperature ranges at which conversion occurred were found to be lower for K2CO3 than for KCl. Subsequently, char conversion occurred over a relatively narrower temperature range for K2CO3 than observed for KCl. The catalytic behaviour of K2CO3 and KCl was confirmed by the results obtained. The results also indicated that the catalytic influence of K2CO3 is greater than that of KCl and that KCl is more susceptible to deactivation by minerals and inorganic compounds present in the coal than K2CO3.
Different analytical techniques (XRF and XRD) were used to determine the extent of
interaction of the catalysts used with the char material in the 5 K-wt% ‘doped’ coal samples. From the XRF results, it was observed that the K2O content was reduced after heat treatments in CO2, however, no potassium crystalline phases were observed in the XRD results after heat treatments in CO2. The reduced K2O content may be attributed to the potassium been taken up in other mineral matter during char reaction with CO2, forming new amorphous inorganic complex compounds. Thus the potassium retained in the sample after heat treatment, indicated by the XRF results, may be in an amorphous phase.
Mass spectrometry (MS) indicated that temperatures at which the maximum rate of
evolution of gaseous species occurred were relatively lower for K2CO3 loaded char samples iv than observed for KCl loaded samples. In addition, no mass-to-charge ratio (m/z) peak at 39 atomic mass unit (amu) from the MS results was observed, indicating that no potassium was detected in the gaseous phases for all the char samples. The undetected potassium in the gaseous phase may be due to the detection limit of the MS equipment.
The MS results also indicated that addition of the catalyst facilitates the evolution of H2
from the coal char samples. Addition of the catalysts to the samples lowered the temperature at which maximum H2 was given off. The shift to lower temperatures was observed with increased catalyst loadings for both K2CO3 and KCl loaded samples.Thesis (MSc (Chemistry))--North-West University, Potchefstroom Campus, 201
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McKay, Andrea J. "Potassium infusion in chronic potassium depleted rats rapidly reverses defective thick ascending limb chloride reabsorption by an aldosterone independent mechanism." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6753.
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Previous studies from our laboratory, using a modified loop microperfusion technique (microstop-flow conductivity) in vivo, have shown that NaCl transport by the thick ascending limb (TAL) is impaired in potassium depleted (K-DEP) rats. The degree of impairment in TAL NaCl transport is highly correlated with plasma potassium (K$\sp+$) concentration and is completely reversed when extracellular fluid potassium concentration (ECF (K$\sp+$)) is increased by acute potassium infusion. These experiments assessed NaCl transport by the TAL in the absence of axial flow by measuring the conductivity of tubular fluid emerging from an early distal tubule site after different intervals of stop-flow (10-60 seconds) in perfused nephrons. Since these measurements of TAL transport were made in the absence of axial flow, the significance of the defect in NaCl transport in K-DEP rats could not be determined under in vivo conditions of physiological flow and chloride (Cl$\sp-$) delivery. To determine the quantitative importance of this impairment in NaCl transport by the TAL, Cl$\sp-$ reabsorption was measured in functionally isolated perfused single loops of Henle in vivo, using the technique of continuous microperfusion. Cl$\sp-$ reabsorption was measured in loop segments microperfused at 22 nL/minute using a modified perfusate which minimized proximal nephron transport. This modification of the loop perfusate allowed the measurement of furosemide-sensitive Cl$\sp-$ reabsorption in the perfused loop segments such that net Cl$\sp-$ uptake in this study can be attributed primarily to carrier-mediated Cl$\sp-$ transport by the TAL. Others have provided evidence that TAL NaCl reabsorption is aldosterone dependent in adrenalectomized animals. In our rats given a K-free diet, both plasma (K$\sp+$) and plasma (aldosterone) were significantly reduced. Since aldosterone release is regulated by ECF (K$\sp+$), the purpose of the present study was to determine whether an aldosterone deficiency and/or reduced ECF (K$\sp+$) mediates inhibition of TAL Cl$\sp-$ transport in potassium depletion. Using the described microperfusion conditions, it was possible to show that the defect in TAL Cl$\sp-$ reabsorption in K-DEP rats was quantitatively significant and can be rapidly reversed by the acute systemic infusion of potassium. Acute administration of aldosterone, in the presence of sustained hypokalemia, failed to reverse the impairment in TAL Cl$\sp-$ reabsorption in K-DEP rats. However, the acute infusion of potassium, in the presence of an aldosterone antagonist, in K-DEP rats rapidly reversed the defect in TAL Cl$\sp-$ reabsorption to control levels. Additional studies showed that despite normalization of ECF (K$\sp+$) by acute potassium infusion in K-DEP rats, aldosterone levels failed to increase to control levels within this time period. This is the first study to demonstrate that the restoration of plasma (K$\sp+$) in K-DEP rats is not immediately associated with a parallel rise in plasma (aldosterone). As well, new knowledge was obtained from the present studies which showed that although a minimal (aldosterone) is required for normal TAL Cl$\sp-$ transport to occur, this steroid hormone does not regulate Cl$\sp-$ reabsorption by this nephron segment. Therefore, these results provide conclusive evidence that in K-DEP rats the rapid reversal of defective TAL Cl$\sp-$ reabsorption seen with acute potassium infusion occurs via an aldosterone independent mechanism.
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Batthish, Michelle. "Ischemic preconditioning of the myocardium, role of chloride and inward-rectifier potassium channels." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63191.pdf.
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Monaghan, Alan S. "Chloride and potassium channels of enterocytes isolated from guinea-pig small intestinal villi." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338067.
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Simonnet, Clémence. "The chloride/potassium co-transporter KCC2 in synaptic plasticity, hippocampal rhythmogenesis and memory." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS374.
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La formation et la consolidation d’un souvenir dépend au niveau cellulaire de la potentiation à long-terme des synapses excitatrices et au niveau du réseau, de la rythmogenèse hippocampique, nécessitant une transmission GABAergique inhibitrice pour synchroniser les ensembles neuronaux. L’efficacité et la polarité de la transmission GABAergique dépendent du gradient transmembranaire de chlore, contrôlé par le co-transporteur chlore/potassium KCC2. Cependant, KCC2 interagit aussi avec des partenaires protéiques et influence l’excitabilité neuronale ainsi que le fonctionnement et la plasticité des synapses glutamatergiques. Au cours de ma thèse, j’ai étudié le rôle d’une diminution d’expression de KCC2 dans l’hippocampe dorsal, sur l’apprentissage et la mémoire, ainsi que les mécanismes sous-jacents. Mes résultats démontrent une altération de la mémoire spatiale et contextuelle lorsque l’expression de KCC2 est diminuée dans les neurones principaux. Cet effet est associé à une diminution de la potentiation à long terme des synapses ainsi qu’une hyperexcitabilité neuronale et des déficits de rythmogenèse, plus spécifiquement des sharp-wave ripples et des oscillations gamma anormales lors du sommeil. Ces altérations contribuent probablement à des déficits d’apprentissages et de consolidation. Puisque l’expression de KCC2 est diminuée dans des pathologies associées à des troubles cognitifs, mes résultats suggèrent que des stratégies permettant de stabiliser l’expression de KCC2 pourraient être considérées comme options thérapeutiques. J’ai donc commencé à tester cette hypothèse dans un modèle murin pour le syndrome de RettInformation transfer, storage and retrieval in the brain rely on a balance between excitation and inhibition. At the cellular level, memory encoding involves long-term potentiation of excitatory synapses, while at the network level, cortical rhythmogenesis underlies memory encoding and consolidation and requires inhibitory GABAergic signaling to synchronize neuronal ensembles. To maintain the efficacy and polarity of GABA transmission, the chloride/potassium co-transporter KCC2 controls the transmembrane chloride gradients. However, KCC2 also interacts with protein partners and influences neuronal membrane excitability as well as the function and plasticity of glutamatergic synapses. Altogether, KCC2 appears at the crossroads of excitatory and inhibitory transmission. During my PhD, I explored the consequences of KCC2 down-regulation in the dorsal hippocampus on learning and memory, and the underlying mechanisms both at the cellular and network levels. My results demonstrate that KCC2 knockdown in principal neurons of the dorsal hippocampus affects both spatial and contextual memory. This effect is associated with deficits in LTP of hippocampal synapses as well as neuronal hyperexcitability and hippocampal rhythmopathy, including abnormal sharp-wave ripple generation and gamma-band activity during sleep. These alterations likely contribute to impair both memory encoding and consolidation. Since KCC2 is down-regulated in many disorders associated with cognitive impairment, my results suggest that strategies aiming to restore KCC2 expression may hold therapeutic potential in these disorders. I therefore started testing this hypothesis in experimental models of Rett syndrome
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Brumback, Audrey Christine. "Thermodynamic regulation of NKCC1-mediated chloride transport underlies plasticity of GABAA signaling /." Connect to full text via ProQuest. Limited to UCD Anschutz Medical Campus, 2006.
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Thesis (Ph.D. in Neuroscience) -- University of Colorado at Denver and Health Sciences Center, 2006.Typescript. Includes bibliographical references (leaves 86-96). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;
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Sánchez, Brualla Irene. "The potassium-chloride cotransporter KCC2 : a new therapeutic target for spasticity and neuropathic pain." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/666698.
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La espasticidad y el dolor neuropático son síntomas que aparecen frecuentemente tras una lesión de la médula espinal. La espasticidad se define como un aumento del tono muscular que provoca contracturas, mientras que el dolor neuropático se caracteriza por sensaciones dolorosas causadas por una lesión del sistema nervioso. Ambos síntomas reducen la calidad de vida, y los fármacos disponibles no son uniformemente eficaces contra ellos. Por este motivo, la necesidad de aumentar el abanico de tratamientos disponibles contra estos síntomas es una realidad clínica.
Ambos síntomas surgen debido a una desinhibición de las redes neuronales de la médula espinal. Para ser eficaz, la inhibición necesita una baja concentración de cloruro intracelular en las neuronas, que se mantiene gracias al cotransportador potasio-cloruro de tipo 2 (KCC2), que extrae iones cloruro de las neuronas. La expresión de KCC2 se reduce en las motoneuronas tras una lesión de la médula espinal, lo que genera una pérdida de la inhibición y contribuye a la aparición de la espasticidad. De la misma manera, una reducción de KCC2 en el asta dorsal de la médula espinal contribuye a la aparición de dolor neuropático. KCC2 parece ser una diana terapéutica interesante para tratar la espasticidad y el dolor neuropático. Sin embargo, no existen aún fármacos comercializados capaces de aumentar la expresión y la actividad de los cotransportadores KCC2.
El objetivo de la presente tesis es identificar fármacos capaces de activar KCC2 para restaurar la inhibición, con el fin de tratar la espasticidad y el dolor neuropático.
La activación de receptores serotoninérgicos 5-HT2A con TCB-2 [(4-bromo-3,6-dimethoxybenzocyclobuten-1-yl)methylamine hydrobromide] reestablece la expresión de KCC2 y reduce la espasticidad en ratas con una lesión de la médula espinal. Esto nos llevó a estudiar el efecto del TCB-2 sobre la expresión de KCC2 en el asta dorsal y a verificar su acción sobre el dolor neuropático. Descubrimos que TCB-2 aumenta KCC2 en el asta dorsal de las ratas tras una lesión de la médula espinal o de nervio periférico. TCB-2 reduce también el dolor neuropático, pero sólo tras una lesión medular; el efecto analgésico parece depender de KCC2.
En la siguiente etapa del trabajo, hicimos un screening de una librería de fármacos aprobados para uso humano, para encontrar un nuevo fármaco capaz de aumentar la expresión y/o la función de KCC2, en una formulación biodisponible y segura. Identificamos la proclorperazina como una molécula susceptible de aumentar la actividad de KCC2. La proclorperazina reduce la espasticidad con una eficacia similar al baclofeno, el medicamento que se prescribe más habitualmente a los pacientes paraplégicos para tratar la espasticidad, y disminuye la pérdida de KCC2 provocada por la lesión. Sin embargo, la proclorperazina tiene un efecto más modesto en los animales que desarrollan alodinia mecánica como consecuencia de una lesión de la médula espinal. Estos datos preclínicos ratifican el potencial de la proclorperazina como posible indicación terapéutica en el tratamiento de la espasticidad tras una lesión de la médula espinal, con un efecto débil sobre el dolor neuropático.
Por último, investigamos los mecanismos moleculares responsables de la reducción de KCC2 como consecuencia de una lesión medular. Nuestros datos muestran que la activación de la calpaína es el mecanismo que provoca la pérdida de KCC2 y la hiperexcitabilidad de las motoneuronas tras una lesión de la médula espinal.
Esta tesis valida KCC2 como una diana terapéutica en el tratamiento de la espasticidad y el dolor neuropático tras una lesión de la médula espinal.Spasticity and neuropathic pain are common symptoms affecting patients after spinal cord injury. Spasticity is defined as an increase of the muscle tone contributing to cramps, whereas neuropathic pain is characterized by painful responses caused by a damaged nervous system. Both symptoms decrease quality of life, and currently available drugs are not uniformly useful against them. Therefore, the need to expand the range of available treatments to control these diseases is a reality in clinics. Both symptoms arise from a reduced inhibition in the neural networks of the spinal cord. The inhibitory action depends on a low chloride ion concentration in postsynaptic neurons. This low chloride concentration is maintained by the potassium-chloride cotransporter type 2 (KCC2), which extrudes chloride ions from neurons. The expression of KCC2 is markedly decreased in motoneurons after spinal cord injury, which reduces inhibition and contributes to the development of spasticity. A similar reduction in the amount of KCC2 transporters happens in the dorsal horn of the spinal cord, causing neuropathic pain. KCC2 is an interesting therapeutic target to treat both spasticity and neuropathic pain. However, no marketed drug is able to increase KCC2 activity yet. The present thesis aims to identify drugs capable of activating KCC2 to recover inhibition and treat spasticity and neuropathic pain. Activation of serotoninergic 5-HT2A receptors with TCB-2 [(4-bromo-3,6-dimethoxybenzocyclobuten-1-yl)methylamine hydrobromide] recovers KCC2 expression in motoneurons and reduces spasticity in rats with spinal cord injury. This led us to consider if TCB-2 would increase KCC2 in the dorsal horn and alleviate neuropathic pain. We found that TCB-2 increased KCC2 in the dorsal horn of rats with a spinal cord or peripheral nerve injury. TCB-2 reduces neuropathic pain too, but only on spinal cord injury; this analgesic effect is mediated by KCC2. In the next stage of the work, we performed a screening of drugs approved for human use from a library of compounds to identify a new KCC2 enhancer in a bioavailable and safe formulation. We identified prochlorperazine as an enhancer of KCC2 activity, recovering inhibition in motoneurons after spinal cord injury. Prochlorperazine alleviates spasticity with an efficacy that is similar to baclofen, the gold standard medication for the treatment of spasticity, and rescues the downregulation of KCC2 caused by the injury. Prochlorperazine also showed a modest reduction of mechanical hyperalgesia in animals with a spinal cord injury. These preclinical data support prochlorperazine as a new therapy for the treatment of spasticity after spinal cord injury, having a moderate effect on neuropathic pain. Lastly, we studied the molecular mechanisms that cause the loss of KCC2 after a spinal cord injury. Our data prove that calpain is the upstream mechanism of KCC2 downregulation and motoneuron hyperexcitability after a spinal cord injury. This thesis validates KCC2 as a druggable target to treat spasticity and neuropathic pain after spinal cord injury.
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Chang, Martin Chung-San. "On the regulation and function of potassium and chloride channels in human T lymphocytes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ45775.pdf.
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Sanchez, Brualla Irene. "The potassium-chloride cotransporter KCC2 : a new therapeutic target for spasticity and neuropathic pain." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0677.
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La spasticité et la douleur neuropathique sont deux symptômes apparaissant fréquemment après une lésion médullaire. La spasticité est définie comme une augmentation du tonus musculaire qui provoque des contractures, tandis que la douleur neuropathique se caractérise par des sensations douloureuses survenant suite à une lésion du système nerveux.Ces deux symptômes résultent en partie d’une désinhibition des réseaux neuronaux sous-lésionnels lié à une diminution de l’expression du cotransporteur potassium-chlorure type 2 (KCC2). Pour être efficace,l’inhibition nécessite l’action de cette protéine qui extrait les ions chlorure des neurones.L’objectif de la présente thèse est donc d’identifier des médicaments capables d’activer KCC2 afin de restaurer l’inhibition dans le but de traiter la spasticité et la douleur neuropathique.Dans un premier temps, nos résultats ont montré que l’activation de récepteurs sérotoninergiques 5-HT2A avec le TCB-2 rétablit l’expression de KCC2 dans la corne dorsale après une lésion médullaire ou névrectomie. Or le TCB-2 réduit seulement la douleur neuropathique après la lésion spinale.Par la suite, nous avons identifié la prochlorperazine comme une molécule augmentant l’activité de KCC2. Si la prochlorperazine est efficace contre la spasticité, elle a néanmoins un effet plus modeste envers l’allodynie mécanique suite à une lésion médullaire.Enfin, nous avons démontré que la diminution de KCC2,ainsi que l’hyperexcitabilité des motoneurones suite à la lésion, dépendent de l’activation des calpaïnes.Cette thèse valide KCC2 comme une cible thérapeutique dans le traitement de la spasticité et la douleur neuropathique suite à une lésion médullaireSpasticity and neuropathic pain are two symptoms that arise frequently after a spinal cord injury. Spasticity is defined as an increase of the muscle tone contributing to cramps, whereas neuropathic pain consists of painful responses caused by a damaged nervous system. Both symptoms arise, in part, due to a loss of inhibition in the sublesional neural networks, linked to a downregulation of the expression of potassium-chloride cotransporter type 2 (KCC2). For inhibition to be efficient, the action of this protein, which extrudes chloride ions from neurons, is needed.The objective of this thesis is, therefore, to identify drugs capable of activating KCC2 to recover inhibition with the objective of treating spasticity and neuropathic pain.First, our results have proven that the activation of serotonin receptors 5-HT2A with TCB-2 restores KCC2 expression in the dorsal horn after a spinal cord or peripheral nerve injury. However, TCB-2 reduces neuropathic pain after a spinal cord injury exclusively.In the next stage of the work, we have identified prochlorperazine as an enhancer of KCC2 activity. Prochlorperazine is efficient against spasticity, although it only showed a modest reduction of mechanical hyperalgesia in animals with a spinal cord injury.Lastly, we have proven that KCC2 downregulation and motoneuron hyperexcitability after a spinal cord injury depend on the overactivation of calpains.This thesis validates KCC2 as a druggable target to treat spasticity and neuropathic pain after spinal cord injury
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Bandarupalli, Praveen Kumar. "Thermal Analysis of Decomposition Reactions of Aspartic and Glutamic Acids in Potassium Chloride Matrix." Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1391391780.
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Brown, L. D. "The combined electrochemical and microstructural characterisation of the electrochemical reduction of uranium dioxide to uranium metal in molten lithium chloride-potassium chloride eutectic." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1469912/.
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The electrochemical reduction of uranium (IV) oxide to metallic uranium has been studied in lithium chloride-potassium chloride eutectic at 450°C using electrochemical and advanced material characterisation techniques. Electrochemical characterisation identified a single reduction peak occurring at -2.57V with respect to the Ag|Ag+ reference electrode. Sweep voltammetry has identified that the electroreduction of uranium dioxide to metallic uranium occurs via a single, 4-electron transfer, process. The electrochemical reduction has also been observed to be dependent on the activity of O2- ions: An increase in the bulk activity of the oxygen anion impeded the electroreduction process. This phenomena was thermodynamically predicted using Littlewood diagrams produced for the system. In addition, in situ energy dispersive X-ray diffraction investigations were carried out on the I12 JEEP beamline at the Diamond Light Source which resulted in the direct observation of the formation of uranium metal when a uranium dioxide electrode was exposed to electroreduction potentials. No intermediate phases were observed which supports the electrochemical characterisation of this process occurring in a single step. Moreover, microstructural characterisation has been performed on micro-bucket electrodes and metallic cavity electrodes. A coral-like structure was identified after reduction of uranium dioxide and has been attributed to the volume change associated with the reduction. Microstructural reconstructions were performed on four separate sub-volumes in the direction of propagation of the electroreduction process. The porosity was seen to decrease significantly from 16% to 4%. The pore connectivity was also observed to decrease from 93% to 18%. This drastic change in porosity and pore connectivity is reflected in the pore tortuosity which is seen to increase to infinity. This microstructural evaluation is concluded to impede the diffusion of O2- ions out of the electrode resulting in an increased probability of impediment of the electrochemical reduction process.
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Hooge, Susan E. "Impact of potassium chloride on saltiness, bitterness, and other sensory characteristics in model soup systems." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/691.
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Cilento, Eugene Miler. "Ubiquitin Ligase Trim32 and Chloride-sensitive WNK1 as Regulators of Potassium Channels in the Brain." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/431.
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The voltage-gated potassium channel Kv1.2 impacts membrane potential and therefore excitability of neurons. Expression of Kv1.2 at the plasma membrane (PM) is critical for channel function, and altering Kv1.2 at the PM is one way to affect membrane excitability. Such is the case in the cerebellum, a portion of the brain with dense Kv1.2 expression, where modulation of Kv1.2 at the PM can impact electrical activity of neurons and ultimately cerebellum-dependent learning. Modulation of Kv1.2 at the PM can occur through endocytic trafficking of the channel; however mechanisms behind this process in the brain remain to be defined.
The goal of this dissertation was to identify and characterize modalities endogenous to the brain that influence the presence of Kv1.2 at the neuronal plasma membrane. Mass spectrometry (MS) was used to first identify interacting proteins and post-translational modifications (PTM) of Kv1.2 from cerebellar tissue, and the roles of these interactions and modifications on Kv1.2 function were evaluated in two studies:
The first study investigated Trim32, a protein enzyme that catalyzes ubiquitylation, a PTM involved in protein degradation, but also in non-degradative events such as endocytic trafficking. Trim32 was demonstrated to associate and localize with Kv1.2 in cerebellar neurons by MS, immunoblotting (IB), and immunofluorescence (IF), and also demonstrated the ability to ubiquitylate Kv1.2 in vitro through purified recombinant proteins. Utilizing cultured cells through a combination of mutagenesis, biochemistry, and quantitative MS, a working model of Kv1.2 modulation was developed in which Trim32 influences Kv1.2 surface expression by two mechanisms that both involve cross-talk of ubiquitylation and phosphorylation sites of Kv1.2.
The second study investigated WNK1, a chloride-sensitive kinase which regulates cellular homeostasis. Using MS, IB, and IF, WNK1 was demonstrated to associate and localize with Kv1.2 in the cerebellum, and a combination of mutagenesis and pharmacology in both wild-type and WNK1-knockout cultured cells produced a working model whereby WNK1 modulates surface Kv1.2. Activation of the downstream target SPAK kinase, also identified by MS to associate with Kv1.2 in the brain, by WNK1 was additionally found to influence the manner of WNK1 modulation of Kv1.2.
In addition to providing new models of Kv1.2 modulation in the brain, these studies propose novel biological roles for Trim32 and WNK1 that may ultimately impact neuronal excitability.
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Friedel, Perrine. "Régulation post traductionnelle du co-transporteur potassium-chlorure KCC2." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4018.
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Le co-transporteur potassium-chlorure 2, KCC2, contrôle la concentration intracellulaire des ion chlorure (Cl-) dans les neurones matures et régule ainsi la force inhibitrice de l'acide γ-amino butyrique (GABA) et de la glycine, principaux neurotransmetteurs inhibiteurs du système nerveux central. Plusieurs troubles neurologiques sont associés à une diminution de l'expression de KCC2, qui se traduit par l'hyperexcitabilité du réseau neuronal. L'objectif de ce travail de thèse était d'identifier et caractériser les éléments structuraux de la protéine qui sont impliqués dans la régulation de son activité d'un point de vue physiologique et pathologique. J'ai développé de nouvelles approches pour enregistrer l'activité de transporteur d'ions ainsi que l'expression membranaire de KCC2. Ces outils m'ont permis de caractériser de nouveaux éléments structuraux qui régulent le fonctionnement de cette protéine, à savoir, son insertion dans la membrane plasmique, son internalisation ou encore son activité intrinsèque de transporteur d'ions. Enfin, nous avons montré que deux mutations (R952H et R1049C), identifiées chez des patients atteints d'épilepsie idiopathique généralisée (EIG), entrainent la diminution de l'expression membranaire de la protéine et de sa fonction de transporteur de Cl- in vitro. Nos résultats changent la vision actuelle du rôle fonctionnel des régions de KCC2, soulignent l'importance d'étudier l'expression membranaire de la protéine, conjointement à son activité de transporteur, et enfin, démontrent pour la première fois que des mutations sur le gène KCC2, retrouvées chez des patients atteints d'EGI, peuvent perturber le fonctionnement du transporteurThe potassium chloride co-transporter 2, KCC2, controls the intracellular chloride (Cl-) concentration in mature neurons and thus regulates the inhibitory forces of γ-amino butyrique (GABA) and glycine, the major inhibitory neurotransmitters in the central nervous system. Several neurological disorders are associated with down-regulation of KCC2 expression, resulting in hyperexcitability of neural network. The aim of this thesis was to identify and characterize the structural elements of the protein involved in the regulation of its activity under physiological and pathological conditions. I developed new approaches to record ion-transport activity and membrane expression of KCC2. These tools allowed me to characterize new structural elements regulating the functioning of the protein, namely insertion into plasma membrane, internalisation or intrinsic activity of ion-transport. Finally, we showed that two mutations (R952H and R1049C) identified in patients with idiopathic generalized epilepsy (IGE), cause the decrease in membrane protein expression and its function of Cl-transporter in vitro. Our results change the current view on the functional role of KCC2 regions, emphasize the importance of studying membrane protein expression, together with its transporter activity, and finally, demonstrate for the first time that mutations in the KCC2 gene found in patients with EGI, may interfere with transporter function
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Iyer, Venkatraman 1967. "Discretized path integral molecular dynamic simulations with quantum exchange of two electrons in molten potassium chloride." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278142.
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This study presents the use of Feynman's Quantum Path Integral (QPI) approach in the Molecular Dynamic Simulation of two electrons in molten KCl. In this research, we have successfully implemented an original technique to tackle the questions of spin dependent quantum exchange phenomenon between two electrons. It was found that two electrons with antiparallel spins form a stable bipolaronic complex and those with parallel spins repel each other and form two dissociated or singlet states. Calculations of the average energies compare well with previous computational findings by Selloni et al. who used a direct integration of the time dependent Schrodinger equation. The radial distribution function illustrated clearly that the triplet state nests itself among the cations, namely K+. The electron-electron separation distance was found to be ∼3.5 A for the triplet state and the singlet case showed the electrons being repelled as far as possible; namely half the size of the simulation cell ∼7 A.
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Tavana-Roudsari, Aria 1962. "FEEDBACK CONTROL OF CRYSTAL-SIZE DISTRIBUTION IN A POTASSIUM-CHLORIDE CRYSTALLIZER BY ESTIMATION OF NUCLEI DENSITY." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/291283.
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Ianowski, Juan Pablo O'Donnell Michael J. "Mechanisms of transport of sodium, potassium and chloride in Malpighian tubules of Rhodnius prolixus and Drosophila melanogaster." *McMaster only, 2004.
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Salazar, Adriana Isabel Diaz. "Effect of nitrogen, sulfur, and potassium chloride fertilization on the baking quality of soft red winter wheat." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03242009-040439/.
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Galbraith, S. D. "The response of potassium chloride (KCl), ammonium nitrate (AN) solutions and emulsion explosives to plate impact loading." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599271.
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The aim of this study was to investigate the dynamic properties of potassium chloride, AN solutions and a commercial emulsion explosive and to understand their response in terms of shock theory and material properties. A plate impact facility was used to shock the KCl, subjecting it to a uni-axial strain state for the duration of the measurements. Stress and strain histories were recorded using piezo-resistive gauges. KCl is an ionic crystal which, when subject to shocks above 2.2 GPa, has a martensitic phase transformation. The stress histories were explained in terms of the shock and release waves. A novel technique was used to record the reverse phase transformation and to calculate the hysteresis. The assumption that a uni-axial strain state exists behind a phase transformation was verified, for the first time, experimentally. Two techniques were demonstrated that reduce and quantify the piezo-electric response of KCl. Conclusions from this investigation were analysed by two different types of computational simulation. Using a similar methodology to the KCl work a technique has been developed to determine experimentally the Hugoniot of liquids up to pressures of 10 GPa. The Hugoniots of a variety of AN solutions of different strengths and temperatures were recorded. The results were shown to agree with the predictions of two simple equations of state. The technique developed for AN solutions was applied to a commercial emulsion explosive (based on an AN solution) and the Hugoniot determined. The explosive was sensitised by adding quantities of glass micro-balloons and the pressures which induced the first stages of reaction for a given sensitisation were deduced.
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Jenott, Jacob Robert. "Investigating pre-harvest and postharvest interventions to control foodborne pathogens and surrogates on lettuce." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/35432.
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Master of ScienceFood Science Institute
Sara E. Gragg
Leafy greens have been recognized as vehicles for transmission of foodborne pathogens and an effective pre-harvest intervention to control them is currently lacking. After harvest, lettuce is often subjected to chlorinated water to reduce the microbial load in the water and on the lettuce tissue. While moderately effective, there is also a need for improved postharvest interventions. The purpose of Objective I was to 1) determine potassium bisulfate efficacy at reducing populations of Escherichia coli (E. coli) and Listeria innocua (L. innocua) when applied pre-harvest to lettuce, and 2) assess the impact on product quality at harvest. Potassium bisulfate reduced E. coli populations on inoculated lettuce by 1.32 log₁₀ CFU/g (P=0.0002) and L. innocua by 1.18 log₁₀ CFU/g (P=0.0017). No detectable differences were observed in color (P>0.05); however, brown spots were observed on various leaves sprayed with potassium bisulfate. The purpose of Objective II was to employ a blend of benzalkonium chloride, acetic acid, and methyl paraben (BAM) as a postharvest wash on romaine and iceberg lettuce and to 1) determine efficacy at reducing populations of Listeria monocytogenes (L. monocytogenes), E. coli O157:H7 and Salmonella, 2) measure changes in aerobic bacteria throughout the shelf life, and 3) quantify benzalkonium chloride and methyl paraben residues post-washing. To quantify efficacy of BAM reducing pathogenic bacterial populations, fresh-cut romaine and iceberg lettuce were inoculated with L. monocytogenes, E. coli O157:H7, or Salmonella and washed in BAM at concentrations of 0%, 1%, 2% or 3% for one or five minutes. When plated on recovery media, contact time and wash concentration was not significant (P>0.05) for Salmonella on either product. Concentration was significant (P=0.0189) for L. monocytogenes on romaine; however, the greatest reduction observed was <1.0 log₁₀ CFU/g. The 3% wash significantly reduced E. coli O157:H7 on romaine by 1.75 log₁₀ CFU/g, which is 0.66 log₁₀ CFU/g better than the 0% wash. Following washing, wash water was analyzed and data demonstrate that all wash concentrations significantly (P≤0.05) reduced each foodborne pathogen by >2.0 log₁₀ CFU/g in the wash water. To quantify benzalkonium chloride and methyl paraben residues, as well as changes in aerobic bacteria and product quality, fresh-cut romaine and iceberg lettuce were subjected to a 1 minute wash in BAM at concentrations of 0%, 1%, 2%, or 3% and immediately sampled to determine aerobic populations and product quality. Concentrations 0% and 2% were also packaged into retail storage bags and sampled on days 0, 3, 5, and 7. Residues were quantified on these days as well. On day 0, aerobic populations did not vary according to wash concentration (P>0.05). With regards to shelf-life data, the 2% wash significantly reduced (P=0.0203) aerobic bacteria on romaine lettuce; however, no significant difference was observed on iceberg lettuce (P=0.0819). With regards to overall visual appearance of romaine or iceberg lettuce, no significant difference was detected between 0% and 2% BAM washes for each day throughout the shelf-life study (P>0.05). Methyl paraben and benzalkonium chloride residues were <5.0 and <10.0 ppm, respectively, on both products on each sampling day.
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Vidal, Vitor Andre Silva 1991. "Efeito da redução de cloreto de sódio e fosfato sobre as propriedades funcionais de emulsões cárneas adicionadas de sais substitutos." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255102.
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Orientador: Marise Aparecida Rodrigues PollonioDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Com o aumento das informações científicas sobre a relação entre a quantidade e composição de alimentos consumidos na dieta e a saúde, a busca por alimentos mais saudáveis tornou-se relevante nas escolhas dos consumidores. A carne e os produtos cárneos são excelente fonte de oligoelementos, proteínas de alto valor biológico, minerais, vitaminas do grupo B e outros compostos bioativos. Porém, os elevados níveis de ácidos graxos saturados, colesterol, gordura, aditivos e, especialmente sódio tem imposto limites ao seu consumo. Neste contexto, o objetivo deste trabalho foi avaliar a redução do teor de cloreto de sódio (NaCl), principal fonte de sódio e tripolifosfato de sódio (TPFS) em emulsões cárneas de baixo custo (alto teor de carne de frango mecanicamente separada) e em formulações nobres (alto teor de matéria-prima cárnea). O estudo foi dividido em duas etapas. Na primeira, foram elaboradas emulsões cárneas populares (60% de carne de frango mecanicamente separada) contendo sais substitutos (NaCl, KCl e CaCl2) combinados ou isolados com base na força iônica correspondente a 2,5% de NaCl, e formulações com apenas redução de 50% destes sais e TPFS com objetivo de avaliar o efeito sobre as propriedades físico-químicas. Na segunda etapa, foram elaborados 5 tratamentos que apresentaram melhor desempenho na primeira etapa, contendo formulações com blend de sais (NaCl, KCl e CaCl2), e redução de 50% de NaCl e TPFS em emulsões cárneas com alto teor de matéria-prima cárnea. O objetivo da segunda etapa foi igualmente utilizar blends de sais como estratégia para reduzir parcialmente o teor de NaCl e TPFS em emulsões cárneas elaboradas com alto teor de matéria-prima cárnea e verificar o efeito destes nas características físico-químicas a fim de que as matrizes cárneas pudessem ser comparadas. Na primeira e segunda etapa foram determinados: teores de Na, K e Ca, estabilidade de emulsão, pH, avaliação da cor instrumental, Aw, microestrutura e perfil de textura. O KCl foi reportado como o melhor sal substituto ao NaCl, não tendo diferença ou resultando somente em pequenas diferenças em relação aos tratamentos contendo apenas NaCl. O sal substituto CaCl2 causou efeito negativo nas características da matriz cárnea, principalmente na porcentagem de extração das proteínas miofibrilares, ainda que com a mesma força iônica que NaCl. O uso de blend de sais (50% NaCl, 25% KCl e 25% CaCl2) mostrou-se ser uma boa alternativa para redução de sódio. Desta forma, a combinação de sais substitutos (50% NaCl, 25% KCl e 25% CaCl2) e utilização do KCl como sal substituto ao NaCl apresentou-se como uma alternativa para redução de sódio tanto em emulsões cárneas com alto teor de matéria-prima cárnea quanto em emulsão cárnea com alto teor de CMS. No entanto, a redução de fosfato em formulações populares com redução de sódio e adicionada de sais substitutos deve ser melhor investigada para ser implementada
Abstract: The scientific and technological development on food composition and its relationship with food intake and health has led consumer to make healthier food choices. Meat and meat products are excellent source of trace elements, protein with high biological value, minerals, B vitamins and other bioactive compounds. However, their high levels of saturated fatty acids, cholesterol, fat, additives and especially sodium have imposed limits on consumption. In this context, the aim of this study was to evaluate the reduction of sodium chloride (NaCl), the main source of sodium, and sodium tripolyphosphate (STPP) in low-cost meat emulsions (high content of mechanically separated poultry meat) and noble formulations (high content of meat raw material). The study was divided into two stages. First, popular meat emulsions were prepared (60% of mechanically deboned poultry meat) containing salts substitutes (NaCl, KCl and CaCl2) alone or in combination, corresponding to ionic strength of 2.5% NaCl. Then, formulations containing 50% of these salts and STPP were also prepared to evaluate the effect of salt reduction on the physicochemical properties of the processed products. In the second stage, the five treatments with the best performance were prepared, containing blend of salts (NaCl, KCl and CaCl2), and 50% reduction of NaCl and STPP in meat emulsions with high content of meat raw material. The second stage aimed to utilize blends of salts as a strategy to partially reduce NaCl and STPP in meat emulsions containing high content of meat raw material, and to verify its effect on the physicochemical characteristics and compare the meat matrices. In both stages, Na, K and Ca, emulsion stability, pH, instrumental color, aw, microstructure and texture profile were determined. The KCl was reported as the best substitute to NaCl, once little differences were observed in the treatments containing only NaCl. The salt substitute CaCl2 caused a negative effect on the characteristics of the meat matrix especially in the percentage of myofibrillar proteins extracted, despite the similar NaCl ionic strength of all formulations. The use of salt blend (50% NaCl, 25% KCl, and CaCl2 25%) proved to be a good alternative to sodium reduction. Thus, the combination of salt substitutes (50% NaCl, 25% KCl, and 25% CaCl2) and the use of KCl as NaCl substitute may be an alternative to sodium reduction in both emulsions with a high content of meat raw material as with high content of mechanically deboned poultry meat. However, further studies are required on the phosphate reduction in the popular formulations containing low sodium and salt substitutes
Mestrado
Tecnologia de Alimentos
Mestre em Tecnologia de Alimentos
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Ribeiro, Pabblo Atahualpa de Aguiar. "Dinâmica do entupimento de tubos gotejadores sob aplicação de cloreto de potássio (branco e vermelho) via diferentes qualidades de água." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-12012016-152723/.
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Neste trabalho buscou-se avaliar a suscetibilidade dos diferentes modelos de tubos gotejadores ao processo de entupimento quando expostos ao uso de cloreto de potássio (branco e vermelho), aplicados via diferentes qualidades de água. O experimento foi realizado em três fases, por um período de doze meses, analisando o desempenho de 22 modelos de gotejadores (autocompensante e convencionais), com quatro tratamentos e dez repetições, sendo cada repetição representada por um gotejador. Na primeira fase, foram aplicados os seguintes tratamentos: (T1) água com fitoplâncton (lago) e cloreto de potássio branco; (T2) água com fitoplâncton (lago) e cloreto de potássio vermelho; (T3) água potável (laboratório) e cloreto de potássio branco; (T4) água potável (laboratório) e cloreto de potássio vermelho. Na segunda fase foram adicionadas partículas sólidas (solo) às soluções dos tratamentos 1 (T1-Lg/B) e 2 (T2-Lg/V), mantendo a mesma solução do tratamento 3 (T3-Lb/B) e adicionado sulfato de ferro à solução do tratamento 4 (T4-Lb/V). Na terceira fase acrescentou-se hidróxido de ferro às soluções referentes a T1 (T1+So) e T2 (T2+So), mais uma aplicação de uma solução concentrada diretamente nas linhas (tubos gotejadores) sem passar pelo sistema de filtragem, sendo os tratamentos: (T1) Água do lago, cloreto de potássio branco, partículas sólidas e hidróxido de ferro, com o orifício do gotejador posicionado para baixo. (T2) água do lago, cloreto de potássio vermelho, partículas sólidas e hidróxido de ferro, com o orifício do gotejador posicionado para cima. (T3) água do lago , cloreto de potássio branco, partículas sólidas e hidróxido de ferro, com o orifício do gotejador posicionado para cima. (T4) água do lago, cloreto de potássio vermelho, partículas sólidas e hidróxido de ferro, com o orifício do gotejador posicionado para baixo. Os modelos de tubos gotejadores analisados apresentaram desempenhos variáveis, tanto na suscetibilidade ao entupimento quanto no coeficiente de variação de vazão, sugerindo que a arquitetura interna dos gotejadores, foi o fator determinante na caracterização do processo de entupimento. Não foi observada diferença significativa da dinâmica de entupimento com relação à aplicação dos cloretos de potássio branco e vermelho na ausência ou presença de fitoplâncton, mostrando que é possível fazer uso do cloreto de potássio vermelho em fertirrigação, tomando o cuidado de verificar a ausência do elemento ferro no adubo (análise de laboratório). A adição de partículas sólidas e do sulfato de ferro aos tratamentos da primeira fase, passando pelo sistema de filtragem, não potencializou mudanças significativas do cenário de suscetibilidade ao entupimento, nas condições de irrigação da segunda fase. A entrada de partículas sólidas e hidróxido de ferro no sistema sem passar pelo sistema de filtragem (fase 3) e o posicionamento do orifício dos gotejadores para baixo intensificaram o processo de entupimento, onde os modelos convencionais foram os mais sensíveis e alguns modelos autocompensantes foram mais tolerantes a presença destes elementos na água de irrigação. O modelo C3 foi o que apresentou melhor desempenho entre os modelos convencionais nas três fases estudadas, sendo que os modelos A2 e A3 destacaram-se entre os modelos autocompensantes, com uma boa recuperação da vazão ao final dos ensaios.This work aims to evaluate the susceptibility of several dripline models against clogging process when exposed to potassium chloride (white and red), applied through different water qualities (fertirrigation). The experiment was accomplished in three phases, during a period of twelve months, analyzing the performance of 22 drip models (compensating and conventional), with four treatments and ten repetitions, being each repetition a dripper. In the first phase, it was applied the following treatments: (T1) water with fitoplancton (lake) and white potassium chloride; (T2) water with fitoplancton (lake) and red potassium chloride; (T3) potable water (laboratory) and white potassium chloride; (T4) potable water (laboratory) and red potassium chloride. In the second phase, solid particles were added to the solutions of previous treatments 1 (T1-Lg/B) and 2 (T2-Lg/V), maintaining the same solution for treatment 3 (T3-Lb/B) and added iron sulfate to the solution of treatment 4 (T4-Lb/V). In the third phase iron hydroxide was added to the solutions of T1 (T1+So) and T2 (T2+So) treatments, one more application of a concentrated solution directly in drip lines without passing through the filtration system, resulting the following treatments: (T1) water with fitoplancton, white potassium chloride, solid particles and iron hydroxide, with dripper facing down. (T2) water with fitoplancton, red potassium chloride, solid particles and iron hydroxide, with drippers facing up, (T3) water with fitoplancton , white potassium chloride, solid particles and iron hydroxide, with drippers facing up, (T4) water with fitoplancton, red potassium chloride, solid particles and hydroxide of iron, with drippers facing down. Driplines presented a variable performance, regarding the original flow rate levels and variation coefficient, suggesting that internal architecture of emitters, it is a major factor related to clogging resistance to treatments imposed. Statistical differences were not observed for clogging dynamics under the application of white or red potassium chloride, under different water quality conditions, showing that it is possible to use the red potassium chloride for fertirrigation without problems. It is recommended to certify the absence of iron element in the fertilizer based on laboratory analysis. The addition of solid particles and iron sulfate to first phase treatments, going through the filtration system, did not increase the clogging rate or emitters (second phase). The application of solid particles and iron hydroxide in the system without passing through the filtration system (phase 3) and the positioning of drippers facing down, intensified the clogging process. Conventional models were more sensitive and compensating models were more tolerant of this water quality conditions. Models C3 performance better among the conventional models in all phases studied. Models A2 and A3 stood out among compensating models, presenting a good recovery flow rate at the end of the experiment.
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Martins, Douglas Fróes. "Estudo de banhos ácidos para substituição de banho alcalino cianídrico na eletrodeposição de zinco sobre pregos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/18587.
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O objetivo deste trabalho é determinar um processo com qualidade suficiente para produzir revestimentos de zinco a partir de banho ácido à base de cloreto de potássio, por meio de comparação de resultados. O estudo foi realizado comparando dois tipos de banhos disponíveis no mercado, através da caracterização das amostras produzidas em um protótipo da linha de galvanização, projetada para simular o processo industrial. Neste trabalho, foram avaliados parâmetros operacionais e a influência dos aditivos e formulação básica. Na avaliação da qualidade do depósito, além da determinação da espessura de camada, foram avaliadas sua uniformidade através do ensaio de Preece e a morfologia por microscopia eletrônica de varredura. O desempenho em corrosão foi comparado em ensaio de corrosão acelerada em câmara úmida e espectroscopia de impedância eletroquímica. A influência dos aditivos na polarização dos banhos foi avaliada no ensaio de voltametria. As análises permitiram determinar o banho com melhor e mais estável resultado no produto, conhecer a influência das condições operacionais e dos aditivos no depósito, além do melhor desempenho em corrosão.The goal of this study is to determine a process with sufficient quality to produce zinc coatings from acid bath of potassium chloride, by comparison of results. This study was conducted comparing two types of baths available in the market through the characterization of the samples produced in a prototype in-line galvanizing, designed to simulate the industrial process. In this work, were assessed operational parameters and the additives and basic formulation influence. In the assessment of deposit quality, in addition to determining the layer thickness, its uniformity was evaluated by Preece test and morphology by Scanning Electronic Microscopy. The performance in corrosion was compared by accelerated corrosion test in a moist chamber and Electrochemical Impedance Spectroscopy. The additives influence in the baths polarization was evaluated in the Voltammetry test. The analysis allowed to determine the bath with better and more stable results in the product, knowing the influence of operating conditions and additives on the deposit, in addition to better performance in corrosion.
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Diédhiou, Calliste Jérémie. "Mechanisms of salt tolerance sodium, chloride and potassium homeostasis in two rice lines with different tolerance to salinity stress /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=979864097.
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Rocha, Izabela Furtado de Oliveira 1983. "Estudos psicofísicos de formulações de sais hipossódicos = otimização, perfil sensorial e aceitação junto aos consumidores." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254957.
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Orientador: Maria Aparecida Azevedo Pereira da SilvaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Substitutos do cloreto de sódio (NaCl) têm sido utilizados como opção terapêutica para a redução do consumo de sódio entre hipertensos. No entanto, substitutos de NaCl, incluindo o KCl, apresentam sabores indesejáveis, como gosto amargo e adstringência. Assim, os principais objetivos desta pesquisa foram: 1) estudar o poder de salga e o perfil sensorial de alguns substitutos de NaCl, 2 ) estudar a capacidade dos aminoácidos Lornitina e L-arginina em reduzir o gosto amargo provocado pelo KCl em formulações de sais hipossódicos e, 3) desenvolver formulações de sais hipossódicos com perfil sensorial e aceitação similar ao cloreto de sódio, por meio da otimização dos seus componentes através de Metodologia e Superfície de Resposta. Inicialmente, utilizando o Método de Estimativa de Magnitude, desenvolveu-se a função de potência do NaCl e KCl em solução aquosa. Em seguida, uma equipe de 12 julgadores treinados gerou o perfil sensorial do: i) NaCl em solução aquosa a 0,14M, ii) KCl preparado em soluções aquosas às concentrações de 0,06M, 0,20M e 0,68M e, iii) lactato de cálcio (CaLact) preparado em soluções aquosas às concentrações de 0,032M, 0,14M e 0,23M. Na seqüência, a equipe sensorial treinada avaliou o impacto dos aminoácidos L-arginina e L-ornitina sobre o perfil sensorial de várias formulações de sais hipossódicos contendo KCl. Esses resultados foram analisados através de Metodologia de Superfície de Resposta, obtendo-se assim modelos preditivos que possibilitaram o desenvolvimento de três formulações de sal hipossódico, contendo diferentes proporções de NaCl, KCl e L-ornitina. Finalmente, a Função de Potência e a aceitação dessas três formulações de sais hipossódicos foram avaliadas utilizando-se equipe treinada e equipe de consumidores (n= 60 indivíduos). Dos sais pesquisados, o KCl foi o melhor substituto para o NaCl. A L-ornitina mostrou-se eficiente na redução do gosto amargo presente em formulações hipossódicas contendo NaCl e KCl. Uma das formulações de sal hipossódico desenvolvida (composta por NaCl, KCl e L-ornitina) apresentou o perfil sensorial estatisticamente similar (p=0,05) ao do NaCl, com exceção do gosto amargo (0,75+0,85) que foi ligeiramente superior ao do NaCl (0,24+0,45). A aceitação de um preparado à base de carne, e salgado com essa formulação não diferiu significativamente (p<0,05) da aceitação do mesmo preparado à base de carne, porém salgado apenas com NaCl. A utilização desse sal hipossódico mostrou-se vantajosa, pois sua ingestão em preparado à base de carne reduz em aproximadamente 57% o teor de sódio ingerido, comparativamente ao caldo temperado apenas com NaCl, à mesma intensidade de gosto salgado. Assim, pode-se concluir que esta formulação apresenta alta viabilidade de comercialização como um importante substituto do NaCl no combate e controle da HAS, em razão do seu alto poder de salga e boa aceitação junto aos consumidores
Abstract: Systemic Hypertension is a major public health problem that can be controlled by decreasing sodium intake, and increasing the intake of potassium. However, NaCl substitutes, including KCl, usually have undesirable flavor notes, such as bitter taste and astringency. Thus, the objectives of this research were: 1) to study the salting potency and sensory profile of some low-sodium salts, 2) to study the efficiency of the amino acids L-ornithine and L-arginine in reducing the bitter taste present in some low- sodium salts, and 3) to develop formulations of low-sodium salts showing sensory profile and acceptability similar to sodium chloride. Initially, using the Magnitude Estimation Method the Power Function of the NaCl and KCl in aqueous solution was determined. Then, 12 trained judges developed the sensory profile of: i)the NaCl prepared in aqueous solution at 0.14M, iii) the KCl prepared in aqueous solution concentrations at 0.06M, 0.20M and 0.68M and, iii) the calcium lactate (CaLact) prepared in aqueous solutions at concentrations of 0.032M, 0.14M and 0.23M. Then, the trained sensory panel evaluated the ability of the amino acids Larginine (0.0086 M and 0.1M) and L-ornithine (0.01 M and 0.1M) to suppress the bitter taste of several low-sodium formulations. These results were evaluated using Surface Response Methodology, obtaining predictive linear models that allowed the development of three formulations of low-sodium salt containing different proportions of NaCl, KCl and L-ornithine. Finally, the Power Function and consumer acceptance of these three formulations of low sodium salts were evaluated using a panel of trained judges and a panel of consumers (n= 60 subjects). From all the salts studied, KCl was the best substitute NaCl. The L-ornithine was effective in reducing the bitter taste present in the lowsodium formulation containing NaCl and KCl. One of the low-sodium formulatins developed (composed of NaCl, KCl and L-ornithine) showed the sensory profile statistically similar (p=0.05) to that of NaCl, with the exception of its bitter taste (0.75+0.85), which was slightly higher than that of NaCl (0.24+0.45). Acceptance of a meat broth prepared with this low-sodium salt formulation did not differ significantly (p<0.05) from the acceptance of meat broth prepared with NaCl. The use of this formulation of low-sodium salt showed to be advantageous because it represented a reduction of approximately 57% of the sodium present in the meat broth prepared with NaCl, at the same salty intensity. Thus, this formulation of low-sodium salt has a high marketing viability to combat and control systemic hypertension, due to its high salting potency and good acceptance among consumers
Mestrado
Consumo e Qualidade de Alimentos
Mestre em Alimentos e Nutrição
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Ferrer, Patricia Preston. "Functional analysis of the potassium channel beta subunit KCNE3." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://dx.doi.org/10.18452/16264.
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KCNE-Hilfsuntereinheiten assoziieren mit Spannungs-abhängigen K+-Kanälen und verändern dadurch deren subzelluläre Lokalisation, Regulation sowie deren biophysikalische Eigenschaften. Bei heterologer Expression interagiert KCNE3 mit mehreren Poren-bildenden K+-Kanal-Hauptuntereinheiten, deren Ströme dadurch stark modifiziert werden. Aufgrund dieser in vitro-Experimente wurden verschiedenste Funktionen von KCNE3 in den verschiedenen Geweben, wie Gehirn, Herz, Muskel, Kolon und Niere, vermutet. Außerdem wurden Variationen im kcne3-Gen mit menschlichen Skelettmuskelpathologien in Verbindung gesetzt (Abbott et al. 2001). In der gegenwärtigen Literatur wird die physiologische Funktion von KCNE3 eher als komplex und heterogen dargestellt. Auch die direkte Beteiligung von KCNE3 an Krankheiten ist immer noch spekulativ. Zur Untersuchung der physiologischen Funktion von KCNE3 in vivo sowie der potentiellen Rolle bei Krankheiten generierten wir ein kcne3-/- Mausmodell. Die vorliegende Arbeit unterstützt die kritische Rolle der KCNQ1/KCNE3-Kanäle beim Salz- und Flüssigkeitstransport über intestinale und respiratorische Epithelien. Insbesondere fanden wir für die KCNQ1/KCNE3-Heteromere eine basolaterale Lokalisation in Darm- und Trachea-Epithelzellen, wo sie die transepitheliale Cl--Sekretion über basolaterales Recycling von K+-Ionen sowie über Erhöhung der elektrochemischen Triebkraft für apikalen Cl--Austritt fördern. Da weder Veränderungen in der KCNQ1-Expressionsmenge noch in dessen subzellulärer Lokalisation festgestellt wurden, ist die durch KCNE3 verursachte Modifikation der KCNQ1-Kanaleigenschaften essenziell für die hier beschriebene physiologische Rolle im Intestinal- und Trachealtransport. Ferner wird von unserer Arbeit die postulierte Funktion von KCNE3-Heteromeren im Skelettmuskel, Herz und zentralen Nervensystem nicht unterstützt und erweckt somit erhebliche Zweifel über den Beitrag von KCNE3 zu menschlichen Krankheiten, die mit diesen Organen in Verbindung stehen.When overexpressed in heterologous systems, KCNE3 is able to interact with several pore-forming K+ channel alpha subunits greatly modifying their currents. Based on these in vitro evidences, KCNE3 has been proposed to serve different roles in multiple tissues, including brain, heart, muscle, colon and kidney. Additional reports have also linked sequence variations in the KCNE3 gene to cardiac and skeletal muscle pathologies in human. Based on the literature, the overall picture of KCNE3 physiological function is rather complex and heterogeneous, and its direct involvement in pathologies is still speculative and far from being conclusively proven. In order to study the physiological role of KCNE3 in vivo and to address its potential pathological implications, we generated kcne3-/- mice. The present analysis of kcne3-/- mice strongly supports a crucial role of KCNQ1/KCNE3 channels in salt- and fluid secretion across intestinal and airway epithelia. In particular, we found that KCNQ1/KCNE3 heteromers are present in basolateral membranes of intestinal and tracheal epithelial cells where they facilitate transepithelial Cl- secretion through basolateral recycling of K+ ions and by increasing the electrochemical driving force for apical Cl- exit. Because the abundance and subcellular localization of KCNQ1 was unchanged in kcne3-/- mice, the modification of biophysical properties of KCNQ1 by KCNE3 is essential for its role in intestinal and tracheal transport. In addition, our work does not support the postulated role of KCNE3 heteromers in skeletal muscle, heart and CNS physiology, and raises considerable doubts concerning its implication in human pathologies which affect these tissues.
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Zhao, Beibei. "Identification of the cellular and molecular mechanisms governing the post-translational regulation of the neuron- specific potassium/chloride cotransporter KCC2." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40680.
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The neuron-specific K+/Cl- cotransporter 2 (KCC2) is one of the major cation Cl- cotransporter (CCC) proteins in the central nervous system that controls Cl- homeostasis via mediating Cl- extrusion. KCC2 has been established as an essential protein in promoting the maturation of synaptic inhibition during development and controlling neuronal excitibility in the adult central nervous system (CNS). Although various mechanisms are known to regulate KCC2 gene expression, accumulating evidence has shown KCC2 activity can be altered on much shorter time scales in a manner of 10-20 minutes. This suggested post-translational mechanisms, which take place much more rapidly than gene expression, may also be an important means by which KCC2 function can be regulated. However, what these post-translational mechanisms are and how they contribute to the control of KCC2 function remain elusive. In this thesis, I set out to characterize the molecular mechanisms governing the post-translational regulation of KCC2, including its endocytosis, quaternary assembly, and cell surface expression. Specifically, my results suggest: 1) Endogenous KCC2 interacts with the clathrin-mediated endocytosis (CME) machinery; 2) KCC2 is constitutively endocytosed via a CME-dependent mechanism; 3) A di-leucine motif, 657LL658, is essential for both KCC2 constitutive endocytosis and the binding of KCC2 to the CME adaptor protein AP-2 complex; 4) Two regions within KCC2 proximal and central carboxyl terminus respectively mediate KCC2 dimerization, and in particular mutating the 657LL658 residues to alanines completely abolishes KCC2 dimerization; 5) The 657LL658 sequence is highly conserved amongst closely related K+/Cl- cotransporter proteins, but absent from the more distant Na+/Cl- cotransporters controlling Cl- uptake, suggesting an evolutionarily conserved mechanism may regulate the constitutive endocytosis and dimerization of functionally homologous KCC members; and 6) KCC2 expression at the neurLe co-transporteur d’ions K+ et Cl- (KCC2), spécifique aux neurones, est l’un des plus importants co-transporteurs de cations chlorure (CCC) du système nerveux central. Il contrôle l’homéostasie de la cellule en régulant l’extrusion d’ions chlorure. KCC2 est reconnu comme étant une protéine essentielle à la maturation de l’inhibition synaptique au cours du développement et au contrôle de l’excitabilité des neurones dans le système nerveux central de l’adulte. Bien que les mécanismes régulant l’expression de KCC2 soient connus, de nouvelles données suggèrent que l’activité de KCC2 peut aussi être modifiée sur de plus courtes périodes, de l’ordre de 10 à 20 minutes. Ceci suggère qu’un contrôle post-traductionnel, agissant beaucoup plus rapidement qu’un contrôle transcriptionnel, pourrait aussi être important dans la régulation de l’activité de KCC2. Toutefois, la nature de ces mécanismes post-traductionnels et la façon par laquelle ils contribuent à la fonction de KCC2 demeurent inconnus.Dans cette thèse, je vise à caractériser les mécanismes moléculaires qui gouvernent la régulation post-traductionnelle de KCC2, incluant son expression à la surface cellulaire, son endocytose et son assemblage quaternaire. Plus spécifiquement, mes résultats suggèrent que: 1) Le KCC2 endogène interagit avec la machinerie d’endocytose par clathrines (CME) ; 2) Le KCC2 est endocyté constitutivement par un mécanisme dépendant des clathrines; 3) Le motif di-leucine 657LL658 est essentiel non seulement à l’endocytose constitutive de KCC2, mais aussi à l’interaction entre KCC2 et le complexe protéique adaptateur AP-2; 4) Deux régions à l’intérieur de KCC2, l’une proximale et l’autre centrale à l’extrémité C-terminale, sont responsables de la dimérisation de KCC2 qui peut être abrogée par la substitution des leucine 657 et 658 par des alanines; 5) La séquence 657LL658 est très conservée par
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Moldrzyk, Jan. "Využití vedlejších energetických produktů a dalších druhotných surovin pro výrobu alfa sádry." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226735.
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Thesis focus on the longterm research in an area of alpha gypsum production by non pressure method in chloride salt solutions production, which is researched by Institute od technology of building materials and components, Faculty of civil engineering for many years. The result of given research is non pressure equipment for alpha gypsum production. The scope of this research was to make a production of alpha gypsum more efficient through modification of the facility itself and through an optimalization of dehydration process. The scientific aim of this process was to compare an influence of dehydratation solutions of CaCl2, NaCl and KCl on the final product provided that molarity of solutions was at the same level.
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Van, Dai Nguyen. "Effect of sodium and potassium chloride supplementation in drinking water on performance of laying hens and broilers under high ambient temperature." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:100-opus-3009.
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Thevenod, Frank. "Regulation of pancreatic and parotid zymogen granule chloride and potassium ion conductance pathways by cytosol nucleotides: Phosphorylation-dependent and -independent mechanisms." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1056737719.
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Telles, Conner James. "Search for the Basolateral Potassium Channel in the Shark Rectal Gland: Functional and Molecular Identification of a Task-1 Channel Coupled to Chloride Secretion." Yale University, 2006. http://ymtdl.med.yale.edu/theses/available/etd-06282006-145001/.
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In the shark rectal gland (SRG), apical Cl[superscript]- secretion through CFTR channels is tightly coupled to a basolateral K[superscript]+ conductance. The identity of this K[superscript]+ conductive pathway is unknown. Studies were performed in the isolated perfused SRG with 16 K[superscript]+ channel inhibitors at their IC50 and with acidic perfusate. During maximal chloride secretion stimulated by forskolin and IBMX, secretion was inhibited >90% by barium chloride, a non-selective inhibitor of K[superscript]+ channels. Specific inhibitors of calcium sensitive, voltage sensitive, ATP sensitive, and inward rectifying K[superscript]+ channels had no effect on chloride secretion. The inhibitors quinidine, quinine, bupivicaine, anandamide, and low perfusate pH (6.0) abruptly and reversibly inhibited secretion by >90%, consistent with the presence of the Two-Pore-Domain (4TM 2P/KCNK/K2P) family of K+ channels. Degenerate primers were designed to regions of high amino acid homology in known mammal and teleost 4TM 2P K[superscript]+ channel subtypes: TWIK, THIK, TASK, TREK, and TRAAK. PCR with cDNA from several shark tissues identified a putative TASK-1 fragment (394 bp) in shark rectal gland, brain, gill, and kidney. 5and 3 RACE PCR was used to obtain the entire 3 sequence and partial 5 sequence of the shark gene. Genome walking was then used to obtain the remaining 5sequence, including 335 bp of untranslated region sequence upstream of the start codon. The full length clone (1282bp) had an open reading frame encoding a protein of 375 amino acids. This isoform was 80% identical at the amino acid level to the human TASK-1 protein (394 amino acids). Major structural features of the human protein were conserved in the shark ortholog, including the four transmembrane segments (M1-M4), the 2P domains (P1 and P2), short NH2- and long COOH-termini, and an extended extracellular loop between M1 and P1. Shark and human TASK-1 full-length clones were expressed in Xenopus oocytes and studied with two electrode voltage clamp (TEVC) techniques. Both the shark and human TASK-1 channel showed identical current voltage relationships (outward rectifying) with a reversal potential near -90 mV compared to water injected controls. The responses to the inhibitor quinine, and the TASK-1 inhibitor bupivacaine, were identical in shark and human TASK-1. However, shark TASK-1 differed from the human ortholog in two critical responses: response to pH and the metal zinc. The pKa for shark TASK-1 was 7.75 vs. 7.37 for human TASK-1, values that are exceedingly close to the arterial pH for each species, suggesting that TASK-1 channels are regulated closely by the ambient pH. An antibody specific to shark TASK-1 was generated and expression of TASK-1 protein in the rectal gland was confirmed by confocal immuno-fluorescent microscopy which revealed localization to the basolateral membrane, with some apical staining. Shark rectal gland TASK-1 appears to be the major K[superscript]+ channel coupled to secretion in the SRG, is the oldest 4TM 2P family member identified to date, and is the first TASK-1 channel identified to play an essential role in chloride secreting epithelia.
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Karim, Lara. "Extravasering vid behandlingar med aciklovir, kaliumfosfat och kaliumklorid inom intensivvården." Thesis, Uppsala universitet, Institutionen för farmaceutisk biovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-415750.
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Extravasation is a condition that can occur during an intravenous administration. This means that the solution administered intravenously goes extravascular. Depending on physiochemical properties of the substance and solution, this can cause different severity of the damage. Extravasation of acyclovir, potassium phosphate and potassium chloride causes severe tissue damage that can, in worst case, lead to tissue necrosis. The purpose was therefore to investigate how acyclovir, potassium phosphate and potassium chloride causes tissue damage due to pH and osmolality and how the tissue damage can be avoided. To answer the purpose, a comprehensive literature search was conducted on three different databases; Pubmed, CINAHL and Cochrane. The literature search was in progress from February 4 to May 14 2020. The literature search generated a total of 42 articles and case reports, of which 13 of these were relevant for the purpose. These 13 articles consisted of two animal studies, three experimental observational studies, two guidelines from Västra Götalands Region, three case reports about acyclovir and three case reports of potassium phosphate and potassium chloride. Two of the experimental observational studies showed that potassium chloride could be diluted with 100 mL of 0,9% sodium chloride or 5% dextrose in water to possibly avoid tissue damage due to extravasation. Such results were not found for either acyclovir or potassium phosphate. The conclusion that could be drawn was that acyclovir caused tissue damage because of its alkaline pH, potassium phosphate because of its hyperosmolality and potassium chloride because of its acidic pH and its hyperosmolality. One way to possibly avoid tissue damage caused by extravasation is to dilute the substances with higher dilution volumes. However, due to the lack of reliability of the included studies, it cannot be safely concluded that tissue damage can be avoided.
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Keeney, Andrea Brooke. "Effects of Potassium Source and Rate on Yield, Quality, and Leaf Chemistry of Dark and Burley Tobacco, and Residual Effects of Soil K Levels." UKnowledge, 2019. https://uknowledge.uky.edu/pss_etds/120.
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Field trials were conducted in 2016, 2017 and 2018 with dark fire-cured, dark air-cured, and burley tobacco at Princeton, Murray and Lexington Kentucky. Tobacco variety used in 2016 was a low converter (LC) variety, varieties used in 2017 and 2018 were LC and higher converter (HC) varieties. Potassium sources used at all locations and in all years were potassium sulfate (K2SO4) and potassium chloride (KCl). Application rates used at all locations and in all years were 93, 186, 279 kg K ha-1along with an untreated control that received no potassium. In all trials, tobacco that was treated with either potassium source yielded numerically higher than the untreated control. In seven out of 10 trials, LC varieties had a higher moisture content than HC varieties. Tobacco treated with KCl had higher chloride levels than tobacco treated with K2SO4.Quality grade index was similar for tobacco treated with KCl compared to tobacco treated with K2SO4. In all trials, tobacco treated with KCl had numerically lower Tobacco Specific Nitrosamines (TSNA) levels than tobacco treated with K2SO4. Reductions in TSNA levels were 30% lower in tobacco treated with KCl compared to tobacco treated with K2SO4.
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Jesus, Ana Laura Tiberio de 1981. "Redução de cloreto de sódio em queijo cottage probiótico : características físico-químicas, microbiológicas e aceitação sensorial." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254564.
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Orientador: José de Assis Fonseca FariaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-24T19:36:36Z (GMT). No. of bitstreams: 1 Jesus_AnaLauraTiberiode_M.pdf: 1612991 bytes, checksum: 3935cc6ba87a724d5aaf02c88338eea5 (MD5) Previous issue date: 2014
Resumo: O sódio é um elemento essencial na alimentação, contudo, o seu consumo em excesso poderá ter efeitos nocivos para a saúde, tais como o aumento da pressão sanguínea e a redução da absorção de cálcio. Devido a estes efeitos, a redução do teor de sódio nos alimentos tem sido uma das prioridades nas campanhas realizadas por órgãos governamentais, nomeadamente no setor de laticínios onde o queijo é considerado um gênero alimentício com elevados níveis deste elemento. Dessa forma, o presente trabalho objetivou avaliar o efeito da substituição parcial de NaCl por KCl e MgCl2 nos parâmetros de qualidade do queijo cottage probiótico durante 28 dias de estocagem refrigerada e verificar a viabilidade da cultura starter e das culturas probióticas utilizadas para o processamento do queijo. Além disso, objetivou-se avaliar a aceitação sensorial para identificar direções para a melhoria de atributos sensoriais do produto perante consumidores. Com base nos resultados obtidos observou-se que o ideal de gosto salgado para o queijo cottage probiótico com NaCl foi de 1,12% (p/p), e as concentrações equivalentes em salinidade para todos os sais hipossódicos avaliados mantiveram-se as mesmas do NaCl (1,12% p/p). As contagens de Lactobacillus acidophilus e Bifidobacterium animalis subsp. lactis variaram de 7,74 a 6,20 e 8,58 a 7,93 log (UFC. g-1), respectivamente no primeiro e no último dia de estocagem, valores esses suficientes para benefícios à saúde humana. Porém, as contagens da cultura starter permaneceram baixas com valores inferiores a 3,0 log UFC. g-1 para todas as formulações. Com relação aos ácidos orgânicos, o ácido lático foi o mais encontrado em todas as formulações, seguido pelo ácido cítrico e ácido acético. Quanto a atividade proteolítica, os resultados demonstraram que a formulação controle (100% p/p NaCl sem probióticos) foi a que apresentou menor atividade durante 28 dias de estocagem refrigerada, diferindo estatisticamente das demais formulações. Todos os queijos desse estudo podem ser classificados como de baixo teor de gordura, porque o teor de gordura variou de 4.33 a 4.69 %, e muito alta umidade (74.60 a 75.59 %), segundo a legislação brasileira. A adição de culturas probióticas e a redução de sódio não provocaram mudanças significativas no perfil de ácidos graxos em todos os queijos formulados. Os resultados demonstraram que todas as formulações de queijo cottage apresentaram potencial probiótico, desde que consumidas numa quantidade adequada (2 porções diárias de 50 g), uma vez que as concentrações dos probióticos permaneceram dentro dos padrões estipulados pela legislação brasileira. Entre as formulações elaboradas com sais hipossódicos, a formulação mais aceita foi aquela com redução de sódio de 25% (p/p) de NaCl e substituição por KCl (12,5% p/p) e MgCl2 (12,5% p/p), e o atributo que mais afetou a aceitação dessas formulações foi a textura das amostras. Dessa forma, o queijo cottage probiótico demonstrou ser uma excelente matriz para inserção de sais-hipossódicos, pois não modifica o poder de salga em relação ao NaCl
Abstract: Sodium intake is essential for the welfare of human being, however, its overconsumption may lead to unhealthy effects, namely increased blood pressure and lower calcium absorption. Due to the aforementioned effects, sodium content in food is one of the main focuses of attention in campaigns by government agencies, especially in the dairy sector where cheese is perceived as being a food with high sodium content. Thus, this study aimed to evaluate the effect of partial replacement of NaCl by KCl and MgCl2 on the parameters of quality probiotic cottage cheese during 28 days of refrigerated storage and to determine the viability of starter culture and probiotic cultures used in cheese processing. Furthermore, the objective was to evaluate the sensory acceptance to identify directions for improving the sensory attributes of the product before consumers.Using magnitude estimation method, the salty flavor in probiotic cottage was generated using 1.12% (w/w) NaCl, and equivalent concentrations in salinity for all low-sodium salts, was the same as for NaCl (1.12% w/w). The counts of Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis ranged from 7.74 to 6.20 and from 8.58 to 7.93 log (CFU. g-1), respectively in the first and last day of storage, enough for benefits to consumers. However, the starter culture counts remained at values below 3.0 log CFU. g-1 for all formulations. Lactic acid was the organic acid found in greater quantities in all formulations, followed by citric acid and acetic acid. The proteolytic activity results showed that the control formulation (100% w/w NaCl without probiotics) showed the lowest activity during 28 days of refrigerated storage, differing from the other formulations. All cheeses of this study can be classified as low-fat, because the fat content ranged 4.33 to 4.69% and very high humidity (74.6 to 75.59%), according to Brazilian regulation. The addition of probiotic cultures and reducing sodium did not cause significant changes in the fatty acid profile of all tested cheeses.The results showed that all the formulations showed probiotic potential if consumed in appropriate portion (2 portions of 50 g daily), since the concentration of probiotics remained within the Brazilian standards. Among formulations prepared with low-sodium salt the best one was that with a reduction of 25%(w/w) sodium substitution of KCl and NaCl (12.5% w/w) and MgCl2 (12.5% w/w) and the attribute that most affected the acceptance was the texture of the samples. Thus, the probiotic cottage cheese proved to be an excellent matrix for the insertion of low-sodium salts, because it does not change the power of brining in relation to NaCl
Mestrado
Tecnologia de Alimentos
Mestra em Tecnologia de Alimentos
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Flagella, Michael. "MOLECULAR AND PHYSIOLOGICAL STUDIES OF ELECTROLYTE AND FLUID TRANSPORT PERTURBATIONS IN NKCC1 AND NHE3 DEFICIENT MICE." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin992433396.
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Callow, Kristen Aileen. "Performance of wild oat (Avena fatua L.), wheat and flax in direct-seeding systems in relation to monoammonium phasphate and potassium chloride rate and placement." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ41685.pdf.
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Horita, Claudia Nakamura 1972. "Redução de sódio em salsichas com alto teor de carne de frango mecanicamente separada = efeito de sais substitutos e derivados de alho sobre atributos de qualidade e segurança." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255101.
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Orientador: Marise Aparecida Rodrigues PollonioTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: A redução do consumo de sódio tem sido recomendado por vários órgãos da saúde em função da correlação positiva entre ingestão de sódio e o desenvolvimento de doenças como a hipertensão arterial, cardiovasculares e renais. Produtos cárneos emulsionados cozidos, principalmente salsichas, estão entre os mais consumidos no Brasil e apresentam elevados teores de sódio. Em algumas categorias de salsichas, matérias-primas menos nobres são adicionadas para reduzir o custo, dentre elas a carne mecanicamente separada de aves (CMS) permitidas em concentrações de até 60%. Cloreto de sódio é um ingrediente multifuncional, pois confere propriedades sensoriais, conservantes e tecnológicas em produtos cárneos. Adicionalmente, em formulações contendo alto teor de CMS sua redução pode ser ainda mais desafiadora pela perda de propriedades funcionais da matriz cárnea (presença de proteínas de menor funcionalidade, porções da medula óssea, alto teor de colágeno e gordura). Desta forma, este trabalho teve como objetivos estudar a influência da redução de sódio na qualidade de salsichas com alto teor de CMS. O trabalho foi dividido em três etapas. Na primeira etapa, blends de cloreto de potássio e cálcio, com força iônica equivalente a 2% NaCl, foram utilizados para substituir 25% ou 50% do NaCl em salsichas contendo 60% de CMS. O objetivo desta etapa foi avaliar o efeito da adição dos blends de sais sobre as propriedades físico-químicas e sensoriais das salsichas. Foram determinados: teor de sódio, Aw, estabilidade de emulsão (batter), avaliação de cor instrumental, perfil de textura, microestrutura e teste de aceitação sensorial. Na segunda etapa, uma formulação contendo blend de sais para substituir 50% NaCl foi selecionada com base nos dados da primeira etapa.e adicionada de derivados de alho (fresco, em pó, óleo comercial e extrato obtido via líquido pressurizado). O objetivo foi investigar os efeitos dos derivados de alho como antioxidantes e antimicrobianos nas formulações de salsichas. As determinações realizadas foram a mesmas da primeira etapa, com exceção da microestrutura e acrescidas da quantificação de Substâncias Reativas ao Ácido Tiobarbitúrico e análises microbiológicas durante 60 dias sob refrigeração. Finalmente, para as mesmas formulações de salsichas, uma terceira etapa foi realizada para avaliar o efeito dos derivados de alho como realçadores de sabor por meio da Análise Descritiva Quantitativa e Teste de Aceitação, utilizando-se duas amostras comerciais para efeito comparativo. Alho fresco e extrato de alho PLE, nas concentrações de 1% e 0,02% respectivamente, apresentaram propriedades antioxidantes e antimicrobianas durante a vida útil das salsichas. Dezoito descritores caracterizaram as amostras das salsichas avaliadas pelos assessores na análise descritiva quantitativa. De forma geral, os tratamentos do estudo apresentaram maior intensidade de sabor e aroma de alho e as amostras comerciais apresentaram aroma e sabor defumado. No teste de preferência, as salsichas comerciais foram as mais aceitas para impressão global, no entanto, salsichas elaboradas para o estudo apresentaram muitas similiaridades entre si em seus perfis sensoriais. Assim, a adição de derivados de alho em salsichas com alto teor de carne mecanicamente separada e adicionada de blends de sais substitutos de NaCl mostraram ser uma alternativa promissora neste seguimento
Abstract: The positive correlation between salt intake and the development of diseases including hypertension, and cardiovascular and renal disorders has led health authorities to recommend the reduction of sodium intake. Cooked emulsified meat products, mainly sausages, have high sodium levels and are among the most consumed products in Brazil. In some types of sausages, the mechanically deboned poultry meat (MDPM) stands out as less noble materials used to reduce costs, allowed in concentrations of up to 60%. Sodium chloride is a multi-functional ingredient, since it provides sensory, preservative, and technological properties in meat products. Sodium reduction can be even more challenging in formulations containing high MDPM levels, due to loss of functional properties of the meat matrix (presence of proteins of lower functionality, portions of the bone marrow, high collagen and fat contents). Thus, this study aimed to investigate the effect of sodium reduction on the quality of sausages with high MDPM content. The study was divided into three stages. In the first step, blends of potassium chloride and calcium chloride with ionic strength equivalent to 2% NaCl were used to replace 25% or 50% of NaCl in sausages containing 60% MDPM. The purpose of this step was to evaluate the effect of the addition of salt blends on the physicochemical and sensory characteristics of the sausages. The following parameters were investigated: sodium content, Aw, emulsion stability (batter), instrumental color, texture profile, microstructure, and sensory acceptance. In the second step, a formulation containing a salt blend to replace 50% NaCl was selected from the first step, and garlic derivatives (fresh, powder, commercial oil, extract obtained by pressurized liquid extraction) were added. The objective was to investigate the effects of garlic derivatives as antioxidant and antimicrobial agents in the sausage formulations. The determinations were the same as the first step, except for microstructure, plus measurement of Thiobarbituric Acid Reactive Substances and microbiological analyses during 60 days of refrigerated storage. Finally, a third step was carried out to evaluate the effect of garlic derivatives as flavor enhancers through quantitative descriptive analysis and acceptance tests, using two commercial samples for comparison. Fresh garlic and garlic PLE extract at concentrations of 1% and 0.02%, respectively, presented antioxidant and antimicrobial properties throughout the shelf life of the sausages. The sausage samples were characterized by eighteen descriptors selected by the assessors in the quantitative descriptive analysis. In general, the treatments had higher flavor intensity and garlic flavor, while the commercial samples exhibited smoky aroma and flavor. In the preference test, the commercial sausages were the most accepted for overall impression, and the sausages prepared for the study presented very similar sensory profiles. Thus, the addition of garlic derivatives in sausage formulations containing high mechanically separated poultry and blends of salt substitutes proved to be a promising alternative in this field
Doutorado
Tecnologia de Alimentos
Doutora em Tecnologia de Alimentos
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Callili, Daniel. "Adubação potássica em videiras 'Niagara Rosada' cultivadas sobre diferentes porta-enxertos /." Botucatu, 2020. http://hdl.handle.net/11449/192043.
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Orientador: Marco Antonio TecchioResumo: A ‘Niagara Rosada’ é a uva mais produzida do estado de São Paulo. Trata-se de uma cultivar de uva para mesa bastante produtiva, com baixo custo de produção, bem adaptada às condições edafoclimáticas da região de Sudeste, além de apresentar boa aceitação no mercado. Para incremento da produtividade e qualidade da uva, alguns manejos fitotécnicos são essenciais e devem ser incorporados ao sistema de produção, dentre eles, o uso de porta-enxertos e a adubação mineral de plantas. Os porta-enxertos apresentam papel fundamental na absorção de nutrientes, contudo, deve-se levar em consideração a compatibilidade com a cultivar copa e a adaptação às condições edafoclimáticas. O potássio é o elemento mais utilizado pelas videiras e pode influenciar diretamente no desempenho produtivo e na qualidade da uva. Assim, a escolha das doses ideais e da fonte potássica são muito importantes. Nesse contexto, os fertilizantes cloreto de potássio e sulfato de potássio são as alternativas mais utilizadas. Sendo assim, o objetivo desse trabalho foi avaliar o efeito de diferentes porta-enxertos, fontes potássicas e doses de potássio na fenologia, nos componentes de produção e de qualidade da uva ‘Niagara Rosada’. O experimento foi realizado durante três ciclos produtivos em vinhedo da Faculdade de Ciências Agronômicas (FCA-UNESP), em Botucatu/SP. A cv. Niagara Rosada, enxertadas sobre os porta-enxertos IAC 572 ‘Jales’ e IAC 766 ‘Campinas’, foram adubadas com os fertilizantes KCl e K2SO4, nas doses an... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: 'Niagara Rosada' is the most produced grape cultivar in the state of São Paulo. It is a very productive cultivar, with low production cost, well adapted to the edaphoclimatic conditions of the Southeast region, in addition to presenting good acceptance in the market. To increase grape productivity and quality, some phytotechnical managements are essential in viticulture, among them, the use of rootstocks and mineral fertilization of plants. Potassium is the element most used by vines and can directly influence the productive performance and quality of the grape. Thus, the choice of potassium source is very important. In this context, potassium chloride and potassium sulfate fertilizers are the best alternatives. The rootstocks can also influence the production and quality of the grape, as they play a fundamental role in the absorption of nutrients. However, compatibility with the cultivar canopy and adaptation to edaphoclimatic conditions must be taken into account. Therefore, the objective of this work was to evaluate the effect of different rootstocks, potassium sources and doses of K2O on phenology, on the production and quality components of the 'Niagara Rosada' grape. The experiment was carried out during three productive cycles in a vineyard of the Faculty of Agronomic Sciences (FCA-UNESP), in Botucatu / SP. The cv. Niagara Rosada, grafted on IAC 572 ‘Jales’ and IAC 766 ‘Campinas’ rootstocks, were fertilized with KCl and K2SO4 fertilizers at annual doses 0, 75, 150 and ... (Complete abstract click electronic access below)
Mestre
50
Rogers, Jennifer J. "Assessment of Mussel Declines in the Clinch and North Fork Holston Rivers Using Histological Evaluations of Vital Organs." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/63925.
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The Clinch River (CR) and North Fork Holston River (NFHR) contain some of the most diverse freshwater mussel assemblages in the United States; however, both rivers are experiencing declines in mussel populations. The first component of this study used histological evaluations and water quality data to determine whether mussels were negatively impacted in the CR zone of decline (ZD) and to inform future management of freshwater mussels in the river. In the 91 kilometer (km) section from Carbo, Virginia (CRKM 431) downstream to Speers Ferry, Virginia (CRKM 340), referred to as the ZD, mussel density decreased >90% from 1979 to 2014 at key sites such as Semones Island (CRKM 378.3) and Pendleton Island (CRKM 364.2). Laboratory propagated mussels were placed in cages in the river for one year from June 2012 to May 2013 at four sites within the ZD and four sites in reaches where mussel populations remain stable or are increasing, a zone of stability (ZS). The survival, growth and histological results indicated that there are continuing impacts to mussels in the ZD. Research investigating impacts to the ZD and methods to improve water quality in this zone are needed.
The laboratory component of this study examined sublethal effects of potassium (K+), chloride (Cl-), and un-ionized ammonia (NH3-N) on mussel tissues at concentrations relevant to those found in the NFHR. Historical industrial activities at Saltville, Virginia, as well as continued pollution of the NFHR from chemical waste ponds at this location, are believed to be significant contributors to mussel declines. Contaminant seepages from the waste ponds that include Cl-, K+, and NH3-N have been shown to be toxic to adult and juvenile mussels.
A three-month laboratory study was conducted to assess impacts to organ tissues (gills, digestive glands, kidneys, and gonads) of adult Villosa iris exposed to environmentally relevant concentrations of K+ (4 and 8 mg/L), Cl- (230 and 705 mg/L), and NH3-N (0.014 and 0.15 mg/L) using histological evaluations. No detectable differences were observed among the histological endpoints from mussels held in treatments and control (p>0.05). The study design was modified and repeated
using increased concentrations of K+ (8, 16, and 32 mg/L) and Cl- (705, 1410, and 2820 mg/L) for a two-month exposure period. Due to issues with maintaining NH3-N in mussel holding chambers, the second study did not the second study did not include NH3-N exposures. Control mussels in both studies had a higher abundance of lipofuscin in kidneys and degraded cytoplasm in the digestive gland diverticula compared to baseline mussels, indicating that captivity influenced mussel tissues. Future studies are needed to more thoroughly address these captivity effects. Both survival and histological data in the second test showed a significant negative effect of the increased concentrations of Cl- and K+, which were representative of those found at some sites in the NFHR downstream of Saltville, Virginia.Master of Science