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Wang, Li. "ASSESSMENT OF THE DRUG-DRUG INTERACTION POTENTIAL OF ANIONIC COMPONENTS IN THE DIET AND HERBAL MEDICINES ON ORGANIC ANION TRANSPORTERS (SLC22 FAMILY)." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3181.
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Numerous natural products are widely used as first-line/alternative therapeutics and dietary supplements in both western and eastern society. However, the safety and efficacy profiles for herbal products are still limited. Organic anion transporters (OATs; SLC22 family) are expressed in many barrier organs and mediate in vivo body disposition of a broad array of endogenous substances and clinically important drugs. As some dietary flavonoids and phenolic acids were previously demonstrated to interact with OATs, it is necessary to explore the potential interaction of such components found in natural products in order to avoid potential OAT-mediated drug-drug interactions (DDIs). The inhibitory effects of 23 natural products were assessed on the function of human (h) OATs, hOAT1 (SLC22A6), hOAT3 (SLC22A7), and hOAT4 (SLC22A11) and/or the murine (m) orthologs mOat1 and mOat3. For compounds exhibiting marked inhibition at initial screening, dose-response curves (IC50 values) and DDI indices were determined. At the initial screening concentrations, 14, 19, and 2 test compounds exhibited significant inhibition on hOAT1, hOAT3, and hOAT4, respectively. Additionally, all test Danshen (a Chinese herbal medicine) hydrophilic components significantly reduced mOat1- and mOat3-mediated substrate uptake at 1 mM. For selected compounds, the IC50 and Ki values were estimated to be in the micromolar or even nanomolar range. Considering the clinical plasma concentration and unbound fraction in plasma, DDI indices for gallic acid, gentisic acid, lithospermic acid, protocatechuic acid, rosmarinic acid, salvianolic acid B, and tanshinol indicated DDIs may occur in vivo in situations of co-administration of these compounds and clinical therapeutics known to be OAT substrates. Finally, a new, rapid, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to quantify gallic acid and gentisic acid in cell lysates in order to measure cellular uptake of these compounds in mOat1- or mOat3-expressing cells. Significant cellular uptake of gallic acid was observed in mOat1-expressing cells, compared with background control cells. The absorptive uptake was completely blocked by probenecid (known OAT inhibitor) at 1 mM. These results indicate that gallic acid is a substrate for mOat1 and suggest that human OAT1 might be involved in the active renal secretion of gallic acid.
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Allada, Rama Kumar. "Thermochemistry of hydrotalcite-like compounds relevant to the fate and transport of aqueous and anionic species in the environment /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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Barneaud-Rocca, Damien. "Caractérisation du site de transport de l'échangeur anionique SLC4A1." Phd thesis, Université Nice Sophia Antipolis, 2013. http://tel.archives-ouvertes.fr/tel-00926767.
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L'AE1 (SLC4A1) est un échangeur chlorure/bicarbonate. Cette protéine est la protéine membranaire la plus abondante à la surface des globules rouges des vertébrés. Elle est participe au transport du CO2 et à l'ancrage du cytosquelette à la membrane plasmique. Des mutations ponctuelles dans la partie membranaire de l'AE1, liées à des pathologies humaines, convertissent l'échange électroneutre en voie de conductance pour le sodium et le potassium ou induisent une fuite de cations dans un échangeur d'anions toujours fonctionnel. Les déterminants moléculaires qui induisent les mouvements d'ions au travers de cet échangeur sont encore inconnus. Le travail présenté a eu pour but d'identifier et de cartographier le site de transport de la protéine normale ou " pathologique ". Nous avons adapté à l'AE1 des outils basés sur la chimie des sulfhydriles capable de donner des informations sur le rôle d'acides aminés dans le site de transport de la protéine. Cette stratégie combinée à l'élaboration d'un modèle tridimensionnel de la protéine in silico basé sur le symporteur uracile/proton nous a permis de définir le site de transport de l'AE1. Nos résultats démontrent qu'un site de transport unique dans l'AE1 peut basculer entre 3 conformations différentes : échange chlorure/bicarbonate, fuite de cation et échange anionique ou fuite de cation uniquement. Ce site met en jeu les segments transmembranaires (TM) 3, 5 et 8 ainsi qu'une boucle intracellulaire très conservée située entre les TM 8 et 9. Le site de transport se structure autour des acides aminés L468, F471, L530, I533 et L673 se terminant au niveau du E681. La boucle intracellulaire 690 à 705 agissant comme un filtre à cations.
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Melhorado, Maria Florbela Silvestre. "Controle da erosão e da infiltração em solo mediterrâneo com aplicação de poliacrilamida aniónica na água de rega." Master's thesis, Universidade de Évora, 1998. http://hdl.handle.net/10174/13142.
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A erosão e a baixa infiltração são problemas comuns nos solos Mediterrâneos do sul de Portugal. Estes solos são frequentemente solos argiluviados caracterizados por um horizonte superficial de pequena espessura e fraca estrutura e um horizonte B "textural" de acumulação de argila, e consequentemente, de baixa permeabilidade. O controle da erosão e a possibilidade de aumentar a infiltração nestes solos são particularmente importantes para a sustentabilidade dos sistemas agrícolas aí implantados, especialmente os de regadio, uma vez que para além de importantes degradações que se verificam na estrutura e produtividade desses solos ao longo do tempo devido ás regas, podem também dar origem a problemas de eutrofização das linhas de água superficiais. A aplicação de pequenas concentrações de poliacrilamida aniónica (PAM), de elevado peso molecular, tem sido recentemente utilizada, na água de rega para aumentar a estabilidade dos agregados do solo e permitir a rápida floculação das partículas em suspensão, diminuindo a erodibilidade do solo regado, e permitindo assim, o controle de erosão e o aumento de infiltração. Neste trabalho foi avaliada a eficácia de pequenas aplicações de PAM na água de rega, em concentrações próximas de 10 ppm (mg/1), no controle da erosão e no aumento da infiltração em sulcos rectilíneos declivosos, comuns à topografia do Alentejo. Idêntica aplicação foi testada em sulcos implantados em terraços de contorno aproximadamente segundo as curvas de nível, com o objectivo de verificar se a utilização de PAM seria ainda eficaz, mesmo quando aplicada num sistema de conservação do solo, como é o dos sulcos em contorno. A quantificação da perda de solo e do transporte de sedimentos ao longo dos sulcos foi realizada utilizando os cones de Imhoff, procedendo-se para tal á sua calibração para o solo em causa. A aplicação de PAM ao longo de 5 regas nos sulcos de contorno permitiu uma redução de 85 a 95% da perda de solo e um aumento da taxa de infiltração de 13 a 53%. Nos sulcos rectilíneos declivosos a aplicação de PAM, ao longo de 3 regas, possibilitou uma redução de 96 a 99% da perda de solo e um aumento da taxa de infiltração de 58 a 9%.
Para além da análise da perda de solo na extremidade dos sulcos, o transporte de sedimentos que se verifica ao longo do sulco foi também objecto de análise. Esse transporte no interior do sulco provoca muitas vezes séria degradação e perda de produtividade na zona de cabeceira dos sulcos, que é negligenciada quando se quantifica a perda de solo apenas na extremidade dos sulcos. A análise do transporte de sedimentos ao longo dos sulcos foi realizada em sulcos de igual comprimento nos sulcos rectilíneos e declivosos e em sulcos diferentes comprimentos no bloco de terraços de contorno. Constatou-se que o transporte de sedimentos na cabeceira dos sulcos de contorno foi reduzido de 30% na nega para 100% na Sa rega e obtiveram-se reduções de 73% a 100% a meio do sulco. O comprimento não teve influência no transporte de sedimentos ao longo do sulco ou na perda de solo. Nos sulcos rectilíneos e declivosos o decréscimo do transporte de sedimentos à cabeceira dos sulcos foi de 87 a 100% com a aplicação de PAM. A degradação do solo pelo processo erosivo da água de rega foi também estudado no bloco de contorno através da análise da alteração selectiva da textura do solo e da forma dos sulcos ao longo do seu comprimento. Nos sulcos tratados com PAM verificou-se comparativamente aos sulcos controle, regados sem a adição de poliacrilamida na água, um aumento médio da percentagem de limo e argila de respectivamente 46% e 42%, e uma diminuição média da percentagem de areia de 16% ao longo do comprimento do sulco. A textura manteve-se franco-arenosa ao longo do sulco, com a excepção da extremidade dos sulcos, onde se verificou uma alteração da textura franco-arenosa para franco-argilo-arenosa. Nos sulcos controle, apesar do decréscimo médio da percentagem de limo e argila e do aumento da percentagem de areia, comparativamente aos sulcos tratados, a textura manteve-se franco-arenosa, com a excepção da zona de cabeceira, onde a textura se alterou de franco-arenoso para arenoso-franco. Quanto à forma dos sulcos verificou-se que nos sulcos tratados com PAM a forma do perfil é geralmente mantida próxima da original e nos sulcos controle a forma é degradada rapidamente, com a escavação dos sulcos devido à elevada erosividade da água. A aplicação de pequenas concentrações de PAM (10 ppm) na água de rega em solos Mediterrâneos com sulcos declivosos e em terraços de contorno foi eficaz no controle da erosão e no aumento da infiltração. A aplicação deste condicionador na água
de rega é possível a custos relativamente baixos e é de fácil utilização. É um sistema recomendável na rega por sulcos em terreno de declive acentuado, onde nenhuma medida de conservação do solo seja utilizada. E, como se viu neste trabalho, mesmo quando sistemas de conservação do solo, como os terraços de contorno são utilizados a aplicação de PAM permite reduções importantes na perda de solo e aumentos consideráveis da taxa de infiltração.
### Abstract - Erosion and low infiltration are common problems in Mediterranean soils in the south of Portugal and in particular in agricultural irrigated soils. These soils are generally, soils with a surface layer of small thickness and poor structure. And the subsurface layer presents an accumulation of clay, giving to this layer very low permeability. The control of erosion and the possibility of increasing infiltration in this soils, are of particular importance for the sustentability of this agriculture systems, since, besides the important degradation that happens in this soils structure and productivity with time, there is also the pollution and eutrofization of surface waters. The application in the irrigation water of small amounts of anionic polyacrylamide (PAM), with high molecular weight, have been recently use in irrigation to increase aggregate stability and allow a fast flocculation of the soil material in suspension, decreasing the irrigated soil erodibility, and that way, allowing the control of erosion and increase of infiltration. In this work, we have done the valuation of the control in erosion and the increase in infiltration provide by the application of PAM in the irrigation water in a concentration of 10 ppm (mg/1). The application was made in traditional furrows, with a high slop, common in Alentejo and in contour furrows. In contour furrows the application of PAM had the intention of testing, if PAM would be efficient in a system of soil conservation, like the contour furrows. The quantification of soil loss and transport of sediments along the furrow was providing by the use of Inhofe cones and it's calibration to Mediterranean soil. The total amount of PAM in contour furrows allowed a reduction of 85 to 95% in the soil loss and an increase of 13 to 53% in the infiltration rate. On the traditional furrows the application of PAM, allowed a reduction of 96 to 99% in the soil loss and an increase of 58 to 79% in the infiltration rate. As the hypothesis place by us, the control provide by PAM in the contour furrows was lower than the control obtain in traditional furrows. In this study the investigation took place not only in soil loss, but also in the transport of sediments along the furrow. The interest of the transport of sediments along the furrow is due to the frequent degradation and loss of productivity in the initial portion
of the furrow, wish is neglected when the valuation of erosion is only in the furrow end. The efficacy of PAM application was also analyse in the transport of sediment along furrows with different length, in the contour furrows. In this study results, we have seen that PAM application provide a reduction of sediment transport in the contour furrows of 30% in the 2" irrigation to 100% in the 5th irrigation in the head of the furrows. In the middle section of the furrow the reduction vary from 73 to 100%. The length of the furrow doesn't seem to have any influence on the transport of sediments and on the soil loss. On traditional furrows the reduction of sediment transport in the furrow head vary from 87 to 100%. The degradation of furrows do the two erosion process was study, on the contour furrows b the analysis of soil texture along the furrow after the 5th irrigation. In the treated furrows, high increased of silt and clay, of 46% and 42% respectively, and a lost of 16% of sand was observed. The texture in the treated furrows change in the end of the furrows, from loamy-sand to loam-clay-sand. And in control furrows the initial section of the furrow was altered from loamy-sand to sand loam. In the shape of the furrow profile we have seen that in treated furrows the profile doesn't change much from the original form. Control furrows were generally deeper in the 5th irrigation, do to the high erosivity.
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Barcelona, Stephanie Suazo. "Investigation of the Mechanism of Substrate Transport by the Glutamate Transporter EAAC1." Scholarly Repository, 2007. http://scholarlyrepository.miami.edu/oa_theses/91.
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The activity of glutamate transporters is essential for the temporal and spatial regulation of the neurotransmitter concentration in the synaptic cleft which is critical for proper neuronal signaling. Because of their role in controlling extracellular glutamate concentrations, dysfunctional glutamate transporters have been implicated in several neurodegenerative diseases and psychiatric disorders. Therefore, investigating the mechanism of substrate transport by these transporters is essential in understanding their behavior when they malfunction. A bacterial glutamate transporter homologue has been successfully crystallized revealing the molecular architecture of glutamate transporters. However, many important questions remain unanswered. In this thesis, I will address the role of D439 in the binding of Na+, and I will identify other electrogenic steps that contribute to the total electrogenicity of the transporter cycle. The role of D439 in the binding of Na+ to the transporter was explored previously in this lab. While it was proposed that the effect of D439 in Na+ binding is indirect, the results described in this thesis provides added support to this work. Here, I will show that the D439 mutation changed the pharmacology of EAAC1 such that THA was converted from a transported substrate to a competitive inhibitor. I will also show that Na+ binding to the substrate-bound mutant transporter occurred with the same affinity as that of Na+ to the substrate-bound wild-type transporter. Therefore, based on these results, D439 is not directly involved in the binding of Na+ to the substrate-bound transporter, but that its effect is rather indirect through changing the substrate binding properties. Na+ binding steps to the empty transporter and to the glutamate-bound EAAC1 contribute only 20% of the total electrogenicity of the glutamate transporter reactions cycle. While K+-induced relocation has been proposed to be electrogenic, there is no experimental evidence that supports it. In this work, I will show that the K+-induced relocation of the empty transporter is electrogenic. Moreover, the results in this work show that the K+-dependent steps are slower than the steps associated with the Na+/glutamate translocation suggesting that the K+-induced relocation determines the transporter?s properties at steady state.
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Miranda, Margarida Sofia Quintanilha. "Transmembrane transport of anions by synthetic transporters." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22273.
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Mestrado em QuímicaThe chloride transport across the phospholipid bilayer assisted by small synthetic molecules were studied by computational methods including quantum calculations followed by molecular dynamics simulations and free energy calculations. A series of twelve tris-thiourea aryl substituted putative transporters, with three different six-membered rings as scaffolds (desmethyl cyclohexane, hexamethyl cyclohexane and benzene) and each of them with four possible aryl substituents (3,5-trifluoromethyl, p-trifluoromethyl, p-nitro and phenyl), were studied in silico in order to understand the experimental transport data previously reported for these molecules. The computational study started with the DFT optimization of twelve chloride complexes in gas phase and in DMSO at the M062X/6-31+G** theory level. The strength of the N-H···Cl- interactions were ascertained through the E2 values obtained from the second order perturbation theory, the Wiberg bond Indexes and the most positive value of the electrostatic potential (VS,max). Overall, these descriptors increases with the binding affinity constants reflecting the electron withdrawing character of the aryl substituents. Thus, the 3,5-trifluoromethyl substituted transporters presented the highest values for the quantum descriptors as well as the highest binding affinity for chloride anion, indicating that these molecules are able to successfully uptake the anion from the water phase and further proceed to its transport across the phospholipid bilayer. Subsequently, the passive diffusion of these chloride complexes were then investigated by MD simulations positioning them either in the bilayer core and water phase. Overall, the MD simulation runs reveal that the transporters were able to promote chloride uptake and release events, consistent with anion carrier transport mechanism. Furthermore, free energy profile for 3,5-trifluoromethyl hexamethyl cyclohexane complex and free chloride were constructed from the potential mean force calculations. The chloride complex has to surpass an energy barrier to cross the middle of the phospholipid bilayer of 2 kcal mol-1 while for the free chloride this energy increases to 19.5 kcal mol-1 indicating that the chloride transport assisted by this receptor is energetically favoured. Another remarkable feature from the MD simulations is that the chloride complexes fit comfortably well below the membrane’s interface which seems to indicate that the receptors are able to operate as a chloride shuttle without leaving the phospholipid bilayer.
O transporte de cloreto pela bicamada fosfolipídica, assistido por pequenas moléculas sintéticas, foi estudado através de métodos computacionais, incluindo cálculos quânticos, simulações de dinâmica molecular e cálculos de energia livre. As propriedades de transporte de um conjunto de doze tris-tioureias contendo um anel central de seis membros (cicloexano, cicloexano hexametilado e benzeno) derivatizado com grupos arilo (3,5-trifluorometilo, p-trifluorometilo, pnitro e fenilo), foram estudados in silico tendo como objetivo a compreensão de dados experimentais de transporte reportados. O estudo computacional iniciou-se com a otimização dos doze complexos em fase gasosa e em dimetilsulfóxido (DMSO), ao nível de teoria de M06-2X/6- 31+G**. A força das interações NH···Cl- foi determinada através dos valores de E2 obtidos da teoria de perturbação de segunda ordem, dos índices de ligação de Wiberg e do valor mais positivo de potencial electroestático (VS,max). Estes descritores aumentam com as constantes de afinidade, refletindo o carácter electroatractor dos substituintes arilo. Assim, os três transportadores com grupos 3,5-trifluorometilo apresentaram os valores mais altos para estes descritores e para afinidade ao cloreto, demonstrando que estas moléculas conseguem de facto capturar um anião da fase aquosa e proceder ao seu transporte através da bicamada fosfolipídica. Seguiu-se o estudo do processo de difusão passiva para estes três complexos por dinâmica molecular, tendo estes sido colocados tanto na fase aquosa como no centro da bicamada fosfolipídica. Estas simulações revelaram que os transportadores eram capazes de promover os processos de captura e libertação de cloreto. Além disso, os perfis de energia livre para o complexo do ligando cicloexano hexametilado derivatizado com 3,5-trifluorometilo e para o cloreto livre foram obtidos através de cálculos de potencial de força média. O complexo tem que superar uma barreira energética de 2 kcal mol-1 para atravessar o meio da bicamada enquanto o cloreto livre tem que ultrapassar uma barreira de energia livre de 19.5 kcal mol-1, i.e. o transporte assistido pelo recetor é energeticamente mais favorável. Outra caraterística importante das simulações está relacionada com o facto dos complexos de cloreto de inserirem confortavelmente abaixo da interface da membrana, indicando que os recetores conseguem operar como transportadores de cloreto sem sair da bicamada fosfolipídica.
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Kilo, Martin, and Thomas Bredow. "Modelling of anion transport in YZrON." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-195357.
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Murray, Ernest Jonathan. "Metalloporphyrins as hosts for anion transport." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263898.
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Kilo, Martin, and Thomas Bredow. "Modelling of anion transport in YZrON." Diffusion fundamentals 2 (2005) 22, S. 1-2, 2005. https://ul.qucosa.de/id/qucosa%3A14352.
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Hussain, Sabir. "Polycyclic receptors for anion binding and transport." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547832.
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Sisson, Adam L. "Anion recognition and transport utilising steroidal receptors." Thesis, University of Bristol, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409425.
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Edwards, Sophie Jane. "Preorganised receptors for anion binding and transport." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685437.
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This thesis is concerned with the synthesis of new anion receptors and describes the anion binding and anion transport properties of these compounds Ten squaramide receptors (A) based on a steroidal cholapod backbone have been synthesised. Association constants for the squaramide receptors with chloride anions were assessed in chloroform and were found to be exceptionally high, up to 1.2 x 1014 M-1 , and in most cases were higher than that of all chloride receptors previously published by the A. P. Davis group. The introduction of electron withdrawing aromatic groups led to increased association constants, as did the introduction of an additional hydrogen bond donor at position Z. The chloride transport properties of the squaramide receptors were also studied, however rates were disappointing. Six receptors based on a trans-decalin scaffold (B) have also been synthesised. These receptors feature two thiourea binding groups and have alkyl chains of varying lengths on the aromatic rings. Association constants of the decalin receptors for chloride were measured in DMSO-d6/O.5% H20 and in chloroform, and were found to be almost identical for each receptor. The chloride transport properties of the decalin receptors were also studied and it was found that as the length of the alkyl substituent R was increased, transport rates also increased up until R = n-hexyl, after which further increasing the length of the alkyl substituent caused transport rates to decrease. Some progress has also been made towards the synthesis of a novel tricyclic receptor (C).
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Clarke, Harriet Jane. "Transmembrane anion transport : investigating mechanism and selectivity." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/418012/.
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In the last decade, the development of synthetic anion transporters has attracted much attention. A variety of small molecules have been established to facilitate the transport of biologically relevant anions such as chloride, bicarbonate and sulfate across lipid bilayers. This interest has been piqued due to their potential as therapeutics for ‘channelopathies’ such as cystic fibrosis and in some cases their anion transport has been linked to anti-cancer activity in cells. This thesis explores a new series of chloride transporters which possessed high binding affinity for oxo-anions such as phosphate and bicarbonate. They were found to transport via an antiport mechanism, with a preference for Cl-/NO3- over Cl-/HCO3-. The series also exhibited some self-association characteristics, which appeared detrimental to their transport activity. The transmembrane transport of fluoride was also investigated using a series of strapped calix[4]pyrroles. The fluoride transport was monitored directly using ion selective electrode and NMR techniques. The length of the strap was found to modulate the fluoride over chloride selectivity, showing fluoride selectivity for the shortest strapped calix[4]pyrroles. Furthermore the fundamental transport mechanism of these calix[4]pyrroles was elucidated as electrogenic by extending the series and employing cationophore coupling techniques. The smallest strapped receptor showed unprecedented Cl- selectivity even in the presence of fatty acid. Additional studies showed the rest of the series’ halide and nitrate selectivity follows an anti-Hofmeister bias.
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Kirk, Karian. "Transport of organic solutes via anion selective channels." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670263.
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Rose, Christoph. "Chemischer Transport fester Lösungen zur Substitution im Anionen-Teilgitter von Ionenkristallen." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968530524.
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Reichel, Valeska. "Molecular and functional analysis of transport proteins for organic anions /." [S.l. : s.n.], 2006. http://www.gbv.de/dms/bs/toc/510955045.pdf.
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Karagiannidis, Louise E. "Neutral receptors for the transport of anions across lipid membranes." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/374679/.
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This report describes a novel method, using 33S NMR techniques, for the detection of sulfate transport across synthetic lipid membranes comprised of 1-palmitoyl-2 oleoylphosphatidylcholine. With this method it was possible to verify that tris(2 aminoethyl)amine based (thio)ureas and cyclic peptide based cryptands can promote the transmembrane transport of sulfate anions. This is a particularly notable accomplishment due to the highly hydrophilic nature of the sulfate anion, and the associated challenges with partitioning such a species into a hydrophobic lipid membrane. Furthermore, a series of bis(thio)urea compounds, based on the 1,2- bisaminocyclohexane scaffold are reported as ion transporters, capable of facilitating both chloride/nitrate and chloride/bicarbonate antiport transport processes. They have also been investigated for binding properties with a variety of anions, using 1H NMR techniques. The influence of stereochemistry on the anion binding and transport ability of the receptors is discussed in detail, with cis-stereoisomers being superior anion transporters to the transanalogues. Receptors based on the ortho-phenylenediamine bis-urea motif have been demonstrated as highly effective anion transporters and function by an antiport mechanism of anion transport. Modification of existing transporters, by adding fluorination at the central phenyl ring or by increasing fluorination at the peripheral phenyl groups, yielded highly potent anion transporters capable of surpassing the activity of the natural anion transporter prodigiosin, for chloride/bicarbonate exchange.
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Judd, Luke William. "Cholapods and cholaphanes : steroid based receptors for anion transport." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544424.
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Ford, Debra Ann. "Enhanced anion transport using some expanded porphyrins as carriers." Thesis, Springfield, Virginia: Available from National Technical Information Service, 1991. http://hdl.handle.net/10945/28166.
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Navakhun, Korakot. "Anion recognition, assembly and transport properties of amidopyrrole derivatives." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417400.
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Cooper, James Arthur. "Novel cyclohexane-based receptors for anion binding and transport." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683940.
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This thesis describes a series of novel anionophores and details their synthesis, anion binding and anion transport capabilities. These novel anionophores are based on a cyclohexane scaffold CA, Figure 1), and are simpler to synthesise than the cholapod and decal ins CB and C in Figure 1 respectively) previously reported by the Davis group. Association constants for chloride were evaluated for the new cyclohexane-based receptors in DMSO-d6/0.S% H20 and, where solubility permitted, in water-saturated chloroform. For the novel cyclohexane systems A, higher association constants were obtained where R = Me as opposed to R = H as well as for those receptors possessing electron-deficient aromatics. However the association constants of these novel systems were found to be somewhat lower than those seen previously with cholapods and decalins. Anion transport by these new cyclohexanes was evaluated by the lucigenin method, with the majority of receptors displaying measurable anion transport activity. As with anion binding, higher levels of transport were obtained where R = Me as opposed to R = H and where aromatics were electron-deficient. Certain cyclohexane-based receptors were found to have similar or improved rates of transport when compared to previously reported receptors from the Davis group, including one which is the most active anion transporter reported by the Davis group. Some progress has also been made towards altering the identity of the hydrogen bond donors on the scaffold, further modifying appended alkyl units and a novel squaramide macrocycle.
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Boysen, Hans, Ines Kaiser-Bischoff, and Martin Lerch. "Anion diffusion processes in O- and N-mayenite investigated by neutron powder diffraction." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192865.
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The crystal structure of mayenite (ideal composition: Ca12Al14O33) consists of a (disordered) calcium-aluminate framework comprising 32 of the 33 oxygen anions. It contains large open cages, 1/6 of them being filled randomly by the remaining
“free” oxygen which is available for diffusion and very high ionic conductivities. This extraframework oxygen could be substituted by nitrogen, opening up possibilities for a pure nitrogen ionic conductor. From high temperature neutron powder diffraction experiments, data analysis employing difference Fourier methods and anharmonic Debye-Waller factors and comparing pure O-mayenite with partly exchanged N/O-mayenite it is concluded that oxygen diffusion proceeds via jump-like processes, intimately coupled to relaxations of Ca and involving exchange of the “free” oxygen with framework oxygen, while nitrogen diffusion appears to proceed via an interstitial process.
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Rasamimanana, Sabrina. "Rétention et transport diffusif d'anions organiques dans la roche argileuse du Callovo-Oxfordien." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066441.
Full textAbstract:
La formation argileuse du Callovo-Oxfordien (COx) est étudiée comme possible roche-hôte d’un stockage profond de déchets radioactifs (projet Cigéo). En effet, en plus d’être très faiblement perméable, elle présente une forte teneur en minéraux argileux, capables de retenir les radionucléides sous forme cationique et d’en retarder ainsi fortement leur transport. Néanmoins, certains colis de déchets sont susceptibles de relarguer d’importante quantité de molécules organiques, capables de complexer ces radionucléides et d’augmenter leur mobilité. Aussi, l’objectif de ce travail a été de mieux comprendre le comportement diffusif de plusieurs molécules organiques d’intérêt vis à vis de cette roche argileuse, en investiguant dans un premier temps leur affinité avec la roche hôte. La rétention de molécules organiques sous forme anionique (acétate, phtalate, adipate, benzoate, citrate) a été quantifiée sur la roche argileuse du COx dispersée à l’aide d’expériences d’adsorption/désorption en batch. Des expériences sur roche décarbonatée et fraction de faible granulométrie ont également été réalisées afin de mettre en évidence les phases de la roche et les fonctions chimiques responsables de la rétention. L’intensité de la rétention, Rd, a pu être corrélée avec le moment dipolaire, µ(Orga.), pour fournir une estimation qualitative de la rétention de molécules organiques polaires hydrophiles. Ainsi, le phtalate, légèrement polaire, présente une rétention réversible (Rd ~1,6 L.kg 1), majoritairement sur les phases argileuses. Le citrate, très polaire et fortement adsorbé (Rd ~ 40 L.kg-1), présente une hystérèse de désorption persistante et une affinité avec différentes phases de la roche (minéraux argileux et oxydes minoritaires). Enfin, l’acétate, l’adipate et le benzoate, peu polaires, présentent une affinité moindre avec la roche (Rd < 0,2 L.kg-1). Le comportement diffusif sur roche compacte de ces anions organiques a alors été étudié. Les valeurs de coefficient de diffusion effectif, De, et facteur de retard ont été quantifiées. La faible diffusivité, [De/D0]ANIONS ORGANIQUES ~ 0,1 à 0,25 × [De/D0]EAU, indique un effet d’exclusion anionique, de même intensité que celui observé pour les anions inorganiques. De plus, les coefficients d’adsorption, Kd, estimés à partir des retards à la diffusion sont environ 2 à 5 fois inférieurs aux coefficients de distribution Rd mesurés sur roche dispersée. Cette différence de comportement n’a pas pu être imputée, ni à des effets de cinétique, ni à des effets de porosité accessible aux anions. Quoiqu’il en soit, les espèces complexantes présentent un retard significatif à la diffusion (Kd > 0,2 L.kg-1), ce qui conforte les capacités de confinement de la roche vis-à-vis de ces espècesThe Callovo-Oxfordian mudstone (COx) is studied as a possible host rock for a deep disposal of radioactive waste (Cigéo project). Indeed, besides being very weakly permeable, it presents a high content of clayey minerals, capable of retaining radionuclides under cationic form and to delay strongly their transport. Nevertheless, some waste packages may release a significant amount of organic molecules, capable of complexing these radionuclides and drastically increase their mobility. So, the objective of this work was to better understand the diffusive behavior of several organic molecules of interest in this mudstone, by investigating at first their affinity with the host rock. The retention of organic molecules under anionic form (acetate, phthalate, adipate, benzoate, and citrate) was quantified on to the dispersed COx mudstone using adsorption/desorption batch experiments. Experiments on decarbonated rock and clay fraction only (< 2µm) were also performed to identify solid phases and chemical functions responsible for the retention. A correlation of the intensity of retention, Rd, was pointed out whit the dipole moment µ(Orga.), providing a qualitative estimate of retention capacity for polar hydrophilic organic molecules. So, phthalate, slightly polar, displays a reversible retention (Rd ~1,6 L.kg-1), mainly on clayey phases. Citrate, very polar and strongly adsorbed (Rd ~ 40 L.kg 1), displays a persistent desorption hysteresis and an affinity to different solid phases (clayey minerals and minor oxides). Lastly, acetate, adipate and benzoate, weakly polar, display a lower affinity with rock (Rd < 0,2 L.kg-1). The diffusive behavior in compact rock of these organic anions was then studied. The effective diffusion coefficient and retardation factor values were quantified. The low diffusivity, [De/D0]ORGANIC ANIONS ~ 0,1 à 0,25 × [De/D0]WATER evidences an effect of anionic exclusion, with a same intensity as that observed for inorganic anions. Furthermore, the Kd adsorption coefficient, estimated from retarded diffusion are approximately 2 to 5 times lower than the Rd distribution coefficient measured on dispersed rock. This difference of behavior was not able to be attributed, or to kinetic effects, nor to accessible porosity to anions effects. Anyway, the complexing species display a significant diffusive retardation (Kd > 0,2 L.kg-1) consolidating the contain properties of the COx mudstone toward this species
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MICHAUT-BEHAR, CLAIRE. "Etude experimentale et simulation de l'acceleration et du transport d'un faisceau d'ions negatifs." Paris 6, 1993. http://www.theses.fr/1993PA066181.
Full textAbstract:
Nous extrayons, d'une source en volume, et accelerons des ions negatifs d'hydrogene a 15 kev. Le faisceau forme est transporte sur une distance d'un metre, jusqu'aux elements de mesure. Une mesure directe du courant, environ 3ma, est realisee grace a une coupe de faraday, une mesure des particules du faisceau est effectuee a l'aide d'un calorimetre et enfin un analyseur de profils du faisceau permet une etude plus fine de la repartition transverse des particules dans le faisceau. En parallele, nous avons developpe un code de simulation numerique de l'extraction et de l'acceleration des ions negatifs. La formation du faisceau dans l'accelerateur n'explique pas tous les phenomenes, notamment la forme et le courant du faisceau suivant la pression dans la region de transport. Par suite de confrontations entre resultats numeriques et experimentaux, nous avons ete amenes a simuler aussi la region de transport. Les resultats portent sur l'etude et l'optimisation de l'accelerateur, et sur l'etude du comportement du faisceau avec la pression. Autant que possible l'experience est comparee a la modelisation numerique du faisceau. Pour une configuration donnee de l'accelerateur, il n'existe qu'une seule polarisation optimale pour chacune de ses trois electrodes. Nous mettons en evidence les collisions du faisceau sur le gaz de la region de transport et de l'accelerateur. Ces collisions provoquent soit des changements de l'etat de charge des particules incidentes, soit l'ionisation des particules cibles. Par suite, pour des pressions suffisamment fortes dans la region de transport, il se cree un plasma, le faisceau est bien confine car sa charge est neutralisee. A tres basse pression, le faisceau eclate sous l'effet de sa charge d'espace tres negative. Nous montrons alors que dans des cas extremes de pression, des gradients de potentiels se forment dans les directions transverse au faisceau et de propagation.
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Martin, Mireille. "Transport et utilisation de certains anions organiques par le rein de rat, in vivo : études par microponctions et différences artérioveineuses." Lyon 1, 1989. http://www.theses.fr/1989LYO1T039.
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Kilo, Martin, Marcela Andrea Taylor, Günter Borchardt, Ines Kaiser-Bischoff, Hans Boysen, Christoph Rödel, and Martin Lerch. "Fast anion-conduction in oxynitrides: oxygen and nitrogen transport in (Y, Zr)-(O, N)." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192927.
Full textAbstract:
Cation doped zirconium oxynitrides (for example zirconium oxide doped with yttrium oxide and nitrogen, \'YZrON\'), having a fluorite-based structure, are suggested to have fairly high nitrogen diffusivity, besides their high oxygen mobility. In the present work, the tracer-diffusion of nitrogen and oxygen was measured in single crystalline \'YZrON\'. Results are compared to the migration pathways and migration enthalpies of nitrogen and oxygen ions as determined by elastic neutron diffraction studies. Excellent agreement of the measured activation enthalpies of nitrogen diffusion (about 2 eV) and oxygen diffusion (about 1 eV) determined by the two methods is found.
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Jones, Graham K. "Expression and anion transport studies on the human erythrocyte anion exchange protein (AE1, band 3)." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245676.
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Menjoge, Amrish, and Sergey Vasenkov. "Suppression of the anomalous relationship between diffusivities of cations and anions by water in imidazolium-based ionic liquids." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192785.
Full textAbstract:
Proton pulsed field gradient (PFG) NMR technique at high magnetic field (17.6 T) and high magnetic field gradients (up to 30 T/m) is applied to study diffusion of the anions and cations in the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][ETSO4]) with
and without water. Excellent NMR spectral resolution attained by this technique allowed high-precision monitoring of the diffusivities of the anions, cations and water in a single experiment. The PFG NMR data show that the anomalous relationship between the ion diffusivities, i.e. larger self-diffusion coefficient of the bulkier [Emim] cation than that of the less bulky [ETSO4] anion, becomes much less pronounced due to addition of water into the ionic liquid. This observation is explained by the distortion of the local structure in the ionic liquid by water molecules leading to a possible loss of the diffusion anisotropy for the cation
diffusion. The reported experimental data are in a qualitative agreement with the most recent results of molecular dynamics simulations (see references 9 and 10).
29
Pope, Andrew J. "The mechanisms of anion transport at the tonoplast of higher plants." Thesis, University of York, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328467.
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White, S. J. "Anion transport in the renal proximal tubule of the rat." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376286.
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Boysen, Hans, Ines Kaiser-Bischoff, and Martin Lerch. "Anion diffusion processes in O- and N-mayenite investigated by neutron powder diffraction: Anion diffusion processes in O- and N-mayenite investigated by neutron powder diffraction." Diffusion fundamentals 8 (2008) 2, S. 1-7, 2008. https://ul.qucosa.de/id/qucosa%3A14148.
Full textAbstract:
The crystal structure of mayenite (ideal composition: Ca12Al14O33) consists of a (disordered) calcium-aluminate framework comprising 32 of the 33 oxygen anions. It contains large open cages, 1/6 of them being filled randomly by the remaining
“free” oxygen which is available for diffusion and very high ionic conductivities. This extraframework oxygen could be substituted by nitrogen, opening up possibilities for a pure nitrogen ionic conductor. From high temperature neutron powder diffraction experiments, data analysis employing difference Fourier methods and anharmonic Debye-Waller factors and comparing pure O-mayenite with partly exchanged N/O-mayenite it is concluded that oxygen diffusion proceeds via jump-like processes, intimately coupled to relaxations of Ca and involving exchange of the “free” oxygen with framework oxygen, while nitrogen diffusion appears to proceed via an interstitial process.
32
Abbas, Farhat. "The effect of surface-solute interactions on the transport of solutes through porous media." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324867.
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Singare, Pravin U. "Ion-Isotopic exchange reaction kinetics in characterization of anion exchange resins Dowex 550A LC and Indion-820." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-184151.
Full textAbstract:
The present paper involves application of nondestructive radioactive tracer technique in characterization of Dowex 550A LC and Indion-820 anion exchange resins. The characterization study was based on kinetic of exchange reactions between inactive iodide/bromide ions on the resins with radioactive iodide/bromide ions in the solution. During iodide exchange reaction performed at a constant temperature of 40.00C, using 1.000 g of ion exchange resins and labeled iodide ion solution of concentration 0.003 mol/L, for Dowex 550A LC resin the specific reaction rate and initial rate of ion exchange was 0.271 min-1 and 0.141 mmol/min respectively, while the amount of iodide ions exchanged was 0.522 mmol, and log Kd was calculated to be 12.1. The above values calculated for Dowex 550A LC resin was higher than the respective values of 0.108, 0.330, 0.036 and 6.0 as obtained for Indion-820 resins. Similar results were obtained for the two resins during bromide exchange reactions, thereby indicating superior performance of Dowex 550A LC resin over Indion-820 resins.
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Ruprecht, Benjamin, Jessica Heine, Martin Wikening, Sylvio Indris, Joseph Wontcheu, Wolfgang Bensch, Thomas Bredow, and Paul Heitjans. "Influence of anion substitution on the lithium diffusivity in hexagonal Li x TiS 2-y Se y." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-188254.
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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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Lakhdar, Youssef. "Synthèse, structure et propriétés physiques de sels de cations radicaux dérives de TétraThiaFulvalène avec des anions organiques : rôle des anions dans la construction du solide cristallin." Angers, 2005. http://www.theses.fr/2005ANGE0025.
Full textAbstract:
Les anions dérivés des diacides (acide oxalique, dérivés de l’acide fumarique, …) présentent différentes formes et symétries susceptibles de modifier l’arrangement structural dans les sels de cations radicaux dérivés de Tétrathiafulvalène (TTF), et par conséquent de modifier les propriétés physiques (transport, magnétisme, optique. . ;) de ces sels. La préparation et l'étude des propriétés physiques des matériaux obtenus par électrocristallisation sont présentées dans ce travail. Dans un premier temps, le donneur BEDT-TTF a été associé à des anions carboxylate et sulfonate. Une modification, même faible de la nature de la couche anionique peut entraîner des arrangements structuraux très différents. Nous nous sommes ensuite orientés vers l’utilisation des donneurs EDTTTF porteurs de groupements amides susceptibles de former des liaisons hydrogène dans l’état cristallin et stabiliser l’ancrage cation-anion. Dans la dernière partie de ce travail, nous avons utilisé les dérivés TTF halogénés. L’exploration de ces sels a permis de mettre en évidence la compétition entre les liaisons hydrogène et halogène. En effet, nous avons observé des interactions fortes de type OanionIcation qui contribuent à rigidifier fortement l’arrangement structuralThe anions derived from diacids (acid oxalic, derived from the fumaric acid. . . ) have various forms and symmetries likely to modify structural arrangement in radical cations salts derived from Tétrathiafulvalène (TTF), and consequently to modify the physical properties (transport, magnetism, optics. . . ) of these salts. The preparation and the study of the physical properties of materials obtained by electrocristallization are presented in this work. Initially, the BEDT-TTF donor was associated with carboxylate and sulphonate anions. A modification, even weak, of the nature of the anion layer can involve different structural arrangements. We focused on the use of EDT-TTF donors bearing amides groups that are suitable to form hydrogen bonds in the crystalline state and to stabilize the cation-anion anchoring. The hydrogen bonds OH. . . O, NH. . . O and CH. . . O which were favored in the various crystalline structures allowed the formation of networks of hydrogen bonds supporting a strong molecular cohesion. The analysis of the stuctures of radical cations salts obtained by the association of primary and secondary amide with the same anion highlights the role of each hydrogen atom on the molecular assembly as well as on the collective physical properties of these salts. In the last part of this work, we have halogenated TTF. The exploration of these salts allowed us to highlight the competition between the hydrogen and halogen bonding. Indeed, we observed strong interactions of Oanion. . . Ication which contribute to strongly rigidify the structural arrangement
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Rheault, Mark Ronald O'Donnell Michael J. "Transport of organic cations and anions by the isolated Malpighian tubules of insects." *McMaster only, 2005.
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Araujo, Daniel Blanc. "O transporte de ânions em células INS-1E não compõe parte do mecanismo da via de amplificação da secreção de insulina estimulada pela glicose." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/42/42137/tde-09112016-151614/.
Full textAbstract:
A via de amplificação da secreção de insulina estimulada por glicose (GSIS) é um fenômeno discutido na literatura, cujos componentes são amplamente debatidos. Evidências sugerem que a condutância a Cl- compõe parte desta via. Porém, o mecanismo pelo qual essa condutância desempenharia papel na via de amplificação ainda é debatido, e, além disso, as ferramentas farmacológicas para estudo dessas afeta o transporte de outros ânions, como bicarbonato (HCO3-). Buscamos neste trabalho compreender a contribuição do transporte desses ânions para a via de amplificação da GSIS levando em consideração a distribuição de Cl- e HCO3- extracelular em células INS-1E. Concluímos que o transporte de ânions nas células INS-1E não contribui para a via de amplificação da GSIS, porém essas células não expressaram os canais CFTR e Anoctamina 1 que foram relacionados com esse fenômeno. Acreditamos que em células secretoras de insulina que expressem esses canais, o transporte de ânions possua alguma relevância funcional.The amplification pathway of glucose stimulated insulin secretion (GSIS) is a phenomenon discussed in the literature, which components are broadly debated. Evidence suggests that Cl- conductance composes part of this pathway. However, the mechanism that this conductance would play role on the amplification pathway still is debated, and, besides that, the pharmacological tools to study these affects transport of other anions, such as bicarbonate (HCO3-). We aimed in this study to understand the contribuition of anion transport for the amplification of GSIS considering the Cl- and HCO3- extracellular distribuition in INS-1E cells. We concluded that anion transport in INS-1E cell line do not contribute for the amplification pathway of GSIS, however those cells do not express CFTR and Anoctamin 1 channels which were related with this phenomenon. We believe that in insulin secretin cells that express those channels, the anion transport may have a functional relevance.
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Kilo, Martin, Marcela Andrea Taylor, Günter Borchardt, Ines Kaiser-Bischoff, Hans Boysen, Christoph Rödel, and Martin Lerch. "Fast anion-conduction in oxynitrides: oxygen and nitrogen transport in (Y, Zr)-(O, N)." Diffusion fundamentals 8 (2008) 8, S. 1-7, 2008. https://ul.qucosa.de/id/qucosa%3A14154.
Full textAbstract:
Cation doped zirconium oxynitrides (for example zirconium oxide doped with yttrium oxide and nitrogen, \''YZrON\''), having a fluorite-based structure, are suggested to have fairly high nitrogen diffusivity, besides their high oxygen mobility. In the present work, the tracer-diffusion of nitrogen and oxygen was measured in single crystalline \''YZrON\''. Results are compared to the migration pathways and migration enthalpies of nitrogen and oxygen ions as determined by elastic neutron diffraction studies. Excellent agreement of the measured activation enthalpies of nitrogen diffusion (about 2 eV) and oxygen diffusion (about 1 eV) determined by the two methods is found.
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Reid, Glen. "Characterization of a human renal organic anion transporter." Doctoral thesis, [S.l.] : [s.n.], 2000. http://webdoc.sub.gwdg.de/diss/2001/reid/reid.pdf.
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Menjoge, Amrish, and Sergey Vasenkov. "Suppression of the anomalous relationship between diffusivities of cations and anions by water in imidazolium-based ionic liquids." Diffusion fundamentals 9 (2009) 3, S. 1-7, 2009. https://ul.qucosa.de/id/qucosa%3A14141.
Full textAbstract:
Proton pulsed field gradient (PFG) NMR technique at high magnetic field (17.6 T) and high magnetic field gradients (up to 30 T/m) is applied to study diffusion of the anions and cations in the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][ETSO4]) with
and without water. Excellent NMR spectral resolution attained by this technique allowed high-precision monitoring of the diffusivities of the anions, cations and water in a single experiment. The PFG NMR data show that the anomalous relationship between the ion diffusivities, i.e. larger self-diffusion coefficient of the bulkier [Emim] cation than that of the less bulky [ETSO4] anion, becomes much less pronounced due to addition of water into the ionic liquid. This observation is explained by the distortion of the local structure in the ionic liquid by water molecules leading to a possible loss of the diffusion anisotropy for the cation
diffusion. The reported experimental data are in a qualitative agreement with the most recent results of molecular dynamics simulations (see references 9 and 10).
42
Li, Shuang Wu. "Transport of valproic acid in the brain : involvement of multiple organic anion transporters /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/7971.
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Farthing, Christine. "Modulation Of CNS Neurotransmitter Levels And Associated Behaviors In Organic Anion Transporter 1 (Slc22a6) And Organic Anion Transporter 3 (Slc22a8) Knockout Mice." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3562.
Full textAbstract:
According to the World Health Organization, mental disorders represent the leading cause of disability in the US generating ~58 billion dollars in medical costs annually. Additionally, among the US population, ~40 million adults suffer from an anxiety disorder and ~14 million suffer from a major depressive disorder. The association between the persistence of these neurobehavioral conditions and central nervous system (CNS) levels of biogenic amines and metabolites has been studied for half a century. Further, a number of drugs interfering with neurotransmission/metabolism are used clinically for treatment of these disorders. Recently, some members of the solute carrier (SLC) superfamily, the SLC22 transporter family, which includes organic anion transporters (Oat1, Oat3), were found to be expressed and functional on the apical membrane of the choroid plexus, a component of the blood-cerebrospinal fluid barrier. The cells of this epithelia form tight junctions, which slows penetration of solutes into the brain and limits passive efflux of endogenous solutes from the brain. Therefore, Oat1 and Oat3 are poised to play an active role in the removal of NTs and metabolites from the CSF. Thus, a better understanding of the underlying roles of OATs in regulating CNS neurotransmitters and connecting their activity to complex behaviors may result in improved understanding of the processes governing CNS homeostasis. Basal locomotor, anxiety-like and depressive-like behaviors in mice of three genotypes (WT, Oat1-/-, and Oat3-/-) across ages (3-18 mo.) were evaluated using behavioral paradigms (e.g. open field activity (OFA), light-dark (LD), marble burying (MB), and tail suspension test (TST)). Secondly, a simple high performance liquid chromatography-ultraviolet/electrochemical detection (HPLC-UV/ECD) method was developed for quantitation of monoamines and metabolites in mouse whole brain. Following completion of behavioral assessments, whole brain concentrations of monoamines and metabolites were determined using the developed method. Lastly, a novel gas chromatography tandem mass spectrometry (GC-MS/MS) method was developed for quantitation of amino acid neurotransmitters, L-glutamic acid (GA) and γ-aminobutyric acid (GABA), in mouse whole brain. The developed method was used for measurement of whole brain concentrations of GA and GABA in a small subset of WT, Oat1-/-, and Oat3-/- mice at 3 and 18 mo.
44
Singare, Pravin U. "Ion-Isotopic exchange reaction kinetics in characterization of anion exchange resins Dowex 550A LC and Indion-820." Diffusion fundamentals 19 (2013) 4, S. 1-21, 2013. https://ul.qucosa.de/id/qucosa%3A13706.
Full textAbstract:
The present paper involves application of nondestructive radioactive tracer technique in characterization of Dowex 550A LC and Indion-820 anion exchange resins. The characterization study was based on kinetic of exchange reactions between inactive iodide/bromide ions on the resins with radioactive iodide/bromide ions in the solution. During iodide exchange reaction performed at a constant temperature of 40.00C, using 1.000 g of ion exchange resins and labeled iodide ion solution of concentration 0.003 mol/L, for Dowex 550A LC resin the specific reaction rate and initial rate of ion exchange was 0.271 min-1 and 0.141 mmol/min respectively, while the amount of iodide ions exchanged was 0.522 mmol, and log Kd was calculated to be 12.1. The above values calculated for Dowex 550A LC resin was higher than the respective values of 0.108, 0.330, 0.036 and 6.0 as obtained for Indion-820 resins. Similar results were obtained for the two resins during bromide exchange reactions, thereby indicating superior performance of Dowex 550A LC resin over Indion-820 resins.
45
Ruprecht, Benjamin, Jessica Heine, Martin Wikening, Sylvio Indris, Joseph Wontcheu, Wolfgang Bensch, Thomas Bredow, and Paul Heitjans. "Influence of anion substitution on the lithium diffusivity in hexagonal Li x TiS 2-y Se y." Diffusion fundamentals 12 (2010) 106, 2010. https://ul.qucosa.de/id/qucosa%3A13915.
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Parker, Mark D. "Expression and anion transport studies on the human erythrocyte anion exchange protein (AE1, band 3) in the yeast Saccharomyces cerevisiae." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310589.
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Kidd, Bryce Edwin. "Cation and Anion Transport in a Dicationic Imidazolium-Based Plastic Crystal Ion Conductor." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23300.
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Here we investigate the organic ionic plastic crystal (OIPC) 1,2-bis[N-(N\'-hexylimidazolium-d2(4,5))]C2H4 2PF6- in one of its solid plastic crystal phases by means of multi-nuclear solid-state (SS) NMR and pulsed-field-gradient (PFG) NMR. We quantify distinct cation and anion diffusion coefficients as well as the diffusion activation energies (Ea) in this dicationic imidazolium-based OIPC. Our studies suggest a change in transport mechanism for the cation upon varying thermal and magnetic treatment (9.4 T), evidenced by changes in cation and anion Ea. Moreover, variable temperature 2H SSNMR lineshapes further support a change in local molecular environment upon slow cooling in B0. Additionally, we quantify the percentage of mobile anions as a function of temperature from variable temperature 19F SSNMR, where two distinct spectral features are present. We also comment on the pre-exponential factor (D0), giving insight into the number of degrees of freedom for both cation and anion as a function of thermal treatment. In conjunction with previously reported conductivity values for this class of OIPCs and the Stokes-Einstein relation, we propose that ion conduction is dominated by anion diffusion between crystallites (i.e., grain boundaries). Using our experimentally determine diffusion coefficient and previously reported PF6- hydrodynamic radius (rH), viscous (" = 4.1 Pa " s) ionic liquid (IL) is present with a cation rH of 0.34 nm. NMR measurements are very powerful in elucidating fundamental OIPC properties and allow a deeper understanding of ion transport within such materials.Master of Science
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Henjakovic, Maja [Verfasser]. "Geschlechtsabhängige Expression renaler und hepatischer Transporter für organische Anionen und Kationen / Maja Henjakovic." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://d-nb.info/1154590178/34.
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Taylor, Andrew Mark. "Biophysical studies on the human erythrocyte anion transporter, band 3." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360571.
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Munns, Denton R. "Drug interactions with the human organic anion transporter 3, OAT3." Diss., Search in ProQuest Dissertations & Theses. UC Only, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1465498.
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