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1
Korsmeyer, Julie. "Anthracroronene in Astrophysical Water-Ice Analogs." Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/scripps_theses/1413.
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Polycyclic aromatic hydrocarbons (PAHs) are the most abundant large organic molecules in space. They are thought to be the main contributor to the unidentified infrared (UIR) emission bands from the interstellar medium (ISM) for several reasons: UIR intensities correspond to carbon abundance, indicating the presence of a carbon-based molecule; UIRs are found in extremely harsh environments which means the source must be a stable molecule. The most important evidence is if the bands in mid-infrared (MIR) or 'fingerprint' region match those of PAHs. Through the infrared spectroscopy of matrix-isolated polycyclic aromatic hydrocarbons a compound's unique neutral and ionized vibrational modes can be identified. In this work, the PAH anthracoronene (AntCor, C36H18) is suspended in a matrix of water-ice, irradiated with ultraviolet (UV) light, and then analyzed using Fourier Transform Infrared (FTIR) spectroscopy. AntCor has not been studied in water ice before, and therefore the vibrational transition data collected (i.e. band positions and intensities) has been compared to coronene and anthracene, the parent molecules, and with theoretical predictions made using density functional theory. The data from this work will be incorporated into the NASA Ames PAH IR Database, where it will be applied to astronomical observations of the unidentified infrared emissions of the ISM, as well as observations of infrared absorption features in dense molecular clouds.
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Cao, Zheng. "LOBELANE ANALOGS WITH VARIOUS METHYLENE LINKER LENGTHS AND ACYCLIC LOBELANE ANALOGS AS POTENTIAL PHARMACOTHERAPIES TO TREAT METHAMPHETAMINE ABUSE." UKnowledge, 2014. http://uknowledge.uky.edu/pharmacy_etds/32.
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Methamphetamine interacts with vesicular monoamine transporter-2 (VMAT2) to inhibit dopamine (DA) uptake and promotes DA release from presynaptic vesicles, increasing cytosolic DA available for methamphetamine-induced reverse transport by DA transporters. By inhibiting VMAT2, lobelane, a defunctionalized, saturated lobeline analog, decreases methamphetamine-evoked DA release and methamphetamine self-administration in rats. In this dissertation structure-activity relationships around the lobelane structure were investigated on racemic lobelane analogs with varying methylene linker lengths at central piperidine ring. Affinity for dihydrotetrabenazine (DTBZ) sites on VMAT2 and for inhibition of VMAT2 function was determined to be 0.88-63 and 0.024-4.6 µM, respectively, and positively correlated. The most potent and selective analog, (±)-cis-2-benzyl-6-(3-phenylpropyl)piperidine [(±)-GZ-730B], for VMAT2 uptake was identified as the lead. The ability of (±)-GZ-730B to inhibit methamphetamine-evoked [3H]DA release from striatal synaptic vesicles and endogenous DA release from striatal slices was determined. The lead analog-induced inhibition of methamphetamine-evoked vesicular [3H]DA release did not translate to inhibition of methamphetamine-evoked DA release in the more intact striatal slices. Moreover, poor water solubility of these lobelane analogs prohibited further in vivo work. Subsequent work focused on analogs with the C-3 and C-4 carbons in the piperidine ring eliminated to afford racemic acyclic lobelane analogs. Generally, acyclic analogs exhibited greater water solubility and less lipophilicity compared to lobelane. Acyclic analogs exhibited affinities (Ki = 0.096-17 μM) for [3H]DTBZ sites that correlated positively with affinity (Ki = 3.3-300 nM) for inhibition of [3H]DA uptake. Pure enantiomers of potent racemic analogs were synthesized, and found to potently, selectively, and competitively inhibit [3H]DA uptake at VMAT2 and to release vesicular [3H]DA in a biphasic manner. Lead enantiomer (R)-N-(1-phenylpropan-2-yl)-3-phenylpropan-1-amine [(R)-GZ-924] inhibited methamphetamine-evoked [3H]DA release from striatal synaptic vesicles, but not from the more intact striatal slices. Surprisingly, (R)-GZ-924 inhibited nicotine-evoked [3H]DA overflow from striatal slices, revealing nonspecific effects. Importantly, (R)-GZ-924 inhibited methamphetamine self-administration in rats. However, the analog also inhibited food-maintained responding, revealing a lack of specificity. The lead analog will not be pursued further as a pharmacotherapy due to the lack of specificity. Further evaluation of the pharmacophore is needed to discover analogs which specifically inhibit the neurochemical and behavioral effect of methamphetamine.
3
Guo, Xinxin. "Opto-thermal measurement of water in human stratum corneum and other substances." Thesis, London South Bank University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323903.
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Birrell, Graham James. "Pharmacological studies of prostanoids and other substances on sensory nerves in arthritic rats." Thesis, University of Edinburgh, 1991. http://hdl.handle.net/1842/26331.
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Intra-arterial (i.a.) injection of 5-hydroxytryptamine (5-HT), excited articular nociceptors from normal and arthritic joints. Responses consisted of two components: (a) a fast transient burst of activity mediated by a 5-HT3-receptor, followed by (b) a delayed, longer-lasting excitation mediated by a 5-HT2-receptor. These responses were shown to occur both <i>in vivo</i> and <i>in vitro</i>. 5-HT also increased the mechanical responsiveness of articular mechanonociceptors via a 5-HT3-receptor. Sensory receptors in arthritic joints were more sensitive to 5-HT to those from normal joints. Administration of the 5-HT3- or 5-HT2-receptor antagonists caused short-lasting reductions in background activity in arthritic joints, as well as in normal joints in which activity had increased following administration of 5-HT. In normal joints, i.a. injection of PGE2, PG12 or the selective IP-receptor agonist cicaprost, excited and caused mechanical sensitization of articular mechanonociceptors. Potentiation of the short-lived excitatory and sensitizing effects of i.a. injected bradykinin on these receptors was also shown. Examination of the effects of PGE2, PG12 and cicaprost <i>in vivo</i> or PGE2, cicaprost, PGD2, and PGF2 alpha <i>in vitro</i>, produced a rank order of potency of PG12 = cicaprost > > PGE2 > > PGD2 = PGF2 alpha In arthritic rats injection of cicaprost and, to a lesser extent, PGE2 was effective in increasing the mechanical responsiveness and resting discharge of articular mechanonociceptors previously depressed by i.v. lysine acetylsalicylate. These results provide evidence for the involvement of IP-receptors, and perhaps EP-receptors, in the excitatory and sensitizing actions of the prostanoids on articular nociceptors, and suggest that PGI2 is the major endogenous prostanoid responsible for the mechanonociceptor sensitization seen in arthritic rat ankle joints. Overall the results suggest that more than one mediator is required to produce conditions of mechanonociceptor sensitization seen in arthritic rat ankle joints. However, as modulators of the responsiveness of nociceptors to other mediators, and as potent excitants themselves, the prostanoids, and in particular PGI2, probably play a major role in the alterations in nociceptor sensitivity seen in arthritic joints.
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Dooley, Audrey Elaine. "The role of serotonin and other neurotransmitter substances in corticogenesis : an in vitro study." Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285153.
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Samaniego, Walter Numas. "Discorhabdin C 3-aza analogs and other potential anticancer and anti-HIV agents : synthesis, characterization and biological evaluation." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/30899.
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Roger, Gaëlle. "Structure et dynamique de substances humiques et polyélectrolytes modèles en solution." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00531539.
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Dans le cadre de l'étude de faisabilité d'un site de stockage de déchets radioactifs, nous nous sommes intéressés au rôle de la matière organique naturelle altérée dans le transport éventuel de radionucléides dans l'environnement. Nous nous sommes plus attachés à la détermination des propriétés électrocinétiques de ces substances humiques dans différentes conditions expérimentales plutôt qu'à la description des réactions de spéciations déjà largement discutées dans la littérature. Pour cela, nous avons choisi de déterminer la taille et la charge de ces substances humiques à l'aide d'une méthode originale : la conductimétrie haute précision. Cette technique associée à une théorie du transport adaptée permet de décrire la mobilité d'espèces chargées en solution en prenant en compte les interactions de paires. Après avoir contribué au développement de cette théorie, nous l'avons utilisée afin de déterminer les propriétés électrocinétiques des substances humiques et d'un polyélectrolyte de référence dans différentes conditions de pH et de force ionique. Tous ces résultats obtenus par conductimétrie ont été corrélés avec d'autres méthodes expérimentales et théoriques : la microscopie à force atomique, la diffusion de lumière dynamique, la zêtamétrie laser et les simulations Monte-Carlo. Les résultats obtenus confirment les hypothèses généralement admises selon lesquelles, les substances humiques sont des petites entités nanométriques ayant des propriétés complexantes vis à vis des cations et sont susceptibles de s'agréger pour former des structures supramoléculaires. L'effet des différents ions présents dans l'environnement (notamment sodium, calcium et magnésium) a été analysé. De plus, la complexation de l'europium – considéré comme un bon analogue de l'américium 241 – a également été étudiée.
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MacPherson, Tom. "Genetic and pharmacological investigation of α4-containing GABAA receptors in conditioned behaviours influenced by cocaine". Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/47585/.
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α4-subunit containing GABAA receptors (α4-GABAARs) are often found co-assembled with δ-subunits in extrasynaptic locations on nucleus accumbens (NAc) medium spiny neurons (MSNs), were they mediate a tonic form of inhibition thought to control the excitability of the neuron. This thesis combines genetic and pharmacological techniques to explore the role of α4-GABAARs in locomotor and reward-conditioned behaviours. Activation of α4-GABAARs by systemic or intra-accumbal administration of THIP, a GABAAR agonist with a preference for δ-subunits, was able to reduce cocainepotentiated locomotor activity in wildtype but not GABAAR α4-subunit knockout mice. Similarly, the ability of repeated cocaine to induce behavioural sensitisation was unaffected in GABAAR α4-subunit knockout mice, but systemic THIP was able to reduce the sensitised increase in locomotor activity in wildtype but not knockout mice. α4-GABAARs are also able to modulate behavioural responses to reward-conditioned stimuli and their enhancement by cocaine. Deletion of GABAAR α4-subunits from dopamine D1-expressing neurons facilitated cocaine-CPP, and activation of α4- GABAARs on NAc D1-MSNs was able to attenuate cocaine-enhancement of cocaine CPP. Conversely, deletion of GABAAR α4-subunits from dopamine D2-expressing neurons increased CRf responding, and activation of α4-GABAARs on NAc D2-MSNs was able to attenuate cocaine-potentiation of CRf responding. These data also indicate that there is a dissociation in the NAc MSNs mediating cocaine-CPP and CRf responding. This may be explained by the different glutamatergic inputs needed to provide information about conditioned cues important for these behaviours. The data presented within this thesis indicate that α4-GABAAR-mediated inhibition of D1- and D2-expressing neurons plays an important physiological role in controlling behavioural responses to conditioned cues. Furthermore, NAc α4βδ GABAARs may provide a potential therapeutic target by which to limit the enhancement of locomotor and conditioned-behaviours by cocaine.
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Stocker, Andreas. "Isolement et charactérisation de substances de la gelée royale." Phd thesis, Université d'Orléans, 2003. http://tel.archives-ouvertes.fr/tel-00008586.
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La thèse a été réalisée en cotutelle entre le Centre de biophysique moléculaire, CNRS UPR 4301, conventionné avec l'Université d'Orléans et l'Université TUM de Munich.<br />La gelée royale est produite dans les glandes des abeilles nourricières Apis mellifera par digestion partielle de pollen et de nectar. La gelée royale joue un rôle clé dans la reproduction, la croissance, l'immunité et l'organisation sociale des abeilles. Elle constitue également une source potentielle de nombreuses molécules à vocation pharmaceutique.<br />Le candidat a analysé des gelées royales d'origines botaniques et géographiques bien définies. Des fractions de peptides et de protéines ont été isolées à l'aide de multiples techniques physico-chimiques. Ces fractions se sont avérées présenter des propriétés antimicrobiennes. Le candidat a également examiné les possibilités d'application pharmaceutique des fractions de gelée royale qu'il a isolées.
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Viljoen, Liandi. "Comparison of South African occupational exposure limits for hazardous chemical substances with those of other countries / Liandi Viljoen." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8640.
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Various hazardous chemical substances are used daily as part of manufacturing and
processing. Exposure to these hazardous chemical substances (HCSs) can cause
adverse health effects in the exposed workers. Occupational exposure limits (OELs)
are used to control exposure to these HCSs and thereby protect workers from the
adverse effects that exposure may induce.
The aim of this study was to compare South African list of OELs as contained in the
Hazardous Chemical Substance Regulations (HCSR) to several developed and
developing countries based on two aspects: (1) the number of substances that are
selected and regulated by the lists of each country (2) and the overall level of the
OELs set by the different countries and jurisdictions. Due to the nature and the large
amount of data the study is divided into two parts. The first part is a comparison of
South African OELs with nine developed countries and jurisdictions along with the
Mine Health and Safety Act Regulation 22.9 (MHSR) of South Africa. The second
comparison was conducted between South African and the four developing BRICS
countries. BRICS is an acronym for: Brazil, Russia, India, China and South Africa,
all are leading developing countries. Substance selection and coverage was
compared by analysing the number of overlapping and uniquely regulated OELs that
existed between countries. The over-all level of OELs was determined and
quantified by using the statistical method, the geometric means of ratios. These
ratios were compared in order to establish how the levels of OELs of the South
African HCSR compare with the level of the various other countries.
Results indicated that there are large and unsystematic differences between the
selection of HCSs that are regulated by different countries and jurisdictions.
Individual coverage and selection of HCSs between the various developing and
developed countries and jurisdictions in the study was inconsistent and dissimilar. A
high number of HCSs are regulated by only one of the various countries included in
this study. Among the developed countries 20.8% of substances are uniquely
regulated, whereas 46% of HCSs are regulated by only one of the various
developing countries. According to the geometric means of ratios Occupational
Safety and Health Administration (OSHA) is the only jurisdiction in a developed
country that has a higher overall level of OELs when compared to South Africa as for
the rest of the developed countries they all yielded a lower overall level of OELs.
American Conference of Governmental Industrial Hygiene (ACGIH) had the lowest
overall level of OELs.
When compared with the BRICS countries South Africa had a higher overall level of
OELs. The average overall level of OELs differs substantially between the BRICS
countries; Russia having the lowest, and Brazil having the highest overall limit when
compared relative to South African HCSR. Strong similarities were found between
South African HCSR and MHSR indicating national similarity. The South African
OELs for HCSs have an overall higher level than the majority of developed and
developing countries. Various factors may be responsible for these differences
among countries and jurisdictions. These factors include, variations in scientific
reasoning, the risk acceptance of the negative impact that various HCSs might
induce and the time lags that countries have between updates. Further differences
may be explained by the difference in consideration of socio-economical and
practical feasibility of an OEL and the predominant industries in a country.<br>Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013
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Wieliczko, Monika J. "Psychological effects of MDMA." Thesis, Canterbury Christ Church University, 2016. http://create.canterbury.ac.uk/14928/.
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Zinberg's Interaction Model implies that the content of a drug-induced experience is a function of the pharmacological properties of the drug, the set (the user’s characteristics e.g. motivation and personality), and the setting (the physical and social context). The current research investigated the function of the set and setting and their role in shaping the psychological effects of 3,4-methylenedioxmethamphetamine (MDMA), as well as their role in reducing the risk of drug abuse. An online survey was distributed among adult MDMA polydrug users (n = 158) and MDMA-naïve controls (alcohol, nicotine and cannabis users, n = 138). Participants answered questions regarding their pattern of drug use, their motivation for MDMA use and the setting (e.g. clubbing, home with friends), as well as the subjective effects of MDMA. Participants also completed a range of self-report measures of self-reflection and insight, emotional intelligence, and personality, as well as a drug dependency measure. MDMA users displayed higher levels of self-reflection and insight, openness to new experience and lower levels of neuroticism and conscientiousness, in comparison to the control group. The significant predictors of self-reflection and insight were openness, emotional intelligence, MDMA use, extraversion and neuroticism. When the analysis was rerun only for the MDMA group, the significant predictors of self-reflection and insight were openness, emotional intelligence and self-insight effects of MDMA. High levels of self-reported negative effects of MDMA were predictors of a problematic drug use. These findings suggest that there might be a relationship between MDMA use and higher levels of self-reflection and insight; however, longitudinal studies are required to further investigate the causality of this relationship. The results add to existing evidence that MDMA has potential for altering emotional experiences. Further research utilising a prospective design is warranted.
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Ni, Liming. "Synthesis and evaluation of new peptidyl phosphonate analogs of benzamidine, lysine and homolysine as irreversible inhibitors for thrombin and other trypsin-like enzymes." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/27080.
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Eckberg, Melanie N. "Forensic Toxicological Screening and Confirmation of 800+ Novel Psychoactive Substances by LC-QTOF-MS and 2D-LC Analysis." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3923.
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Novel psychoactive substances (NPS) represent a great challenge to toxicologists due to the ability of illicit drug manufacturers to alter NPS chemical structures quickly and with ease to circumvent legislation regulating their use. Each time a new structure is introduced, there is a possibility that it has not been previously recorded in law enforcement or scientific databases. Many toxicology laboratories use targeted analytical methods that rely on libraries of known compounds to identify drugs in samples. However, these libraries do not include large numbers of NPS which could result in non-identification or detection.
High-resolution mass spectrometry (HRMS) has been suggested as a method for screening a wide variety of analytes due to its higher sensitivity and mass accuracy as compared to some other forms of mass spectrometry. This technique can generate characteristic MS/MS spectral data for use in compound identification. The main goal of this research was to create a high-resolution mass spectrometry (HRMS) library of NPS and metabolites, as well as validate a method for screening and confirmation of these substances. The study consisted of three main tasks which included; the development of a large high-resolution MS/MS spectral library and database, validation of a method for screening and confirmation of over 800 NPS and metabolites, and screening of blind-spiked and authentic urine specimens to determine real-world applicability of the HRMS library and method.
During validation, several isomeric and structurally related NPS were observed which could not be adequately separated using traditional LC methods. A fourth task was therefore added to investigate improved separation using two-dimensional liquid chromatography (2D-LC). Increased resolving power is achieved in 2D-LC through the coupling of multiple orthogonal separation systems. Ultimately, an on-line, comprehensive method was developed using orthogonal reversed-phase columns in each dimension (RP x RP) for improved separation of co-eluting and isomeric synthetic cannabinoids.
This work can aid laboratories in the identification of NPS through the use of a validated LC-QTOF-MS method for screening and confirmation and HRMS spectral library. In instances where isomeric and structurally related NPS are not sufficiently separated, RP x RP methods can be explored.
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Yan, Lok-Hang. "Approche biomimétique des manadomanzamines et préparation d'analogues de la pelletiérine pour la synthèse biomimétique d'alcaloïdes de lycopodes." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00667616.
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Au cours de ce travail, nous nous sommes intéressés dans une première partie à la synthèse biomimétique d'alcaloïdes de type manzamines et plus particulièrement, aux manadomanzamines. Une étude de la réactivité des deux intermédiaires clés de leur biogenèse, les glutaconaldéhydes et les aminopentadiènals, a été entreprise. Ces mêmes molécules ont ensuite été utilisées comme équivalents synthétiques dans une synthèse biomimétique du squelette pentacyclique de la manadomanzamine A. Une seconde partie est consacrée à la préparation d'analogues stables de la pelletiérine en vue d'une synthèse biomimétique d'alcaloïdes du genre Lycopodium.
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Armand, Damien. "Application de la spectroscopie térahertz à la détection de substances sensibles." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00721831.
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Pour répondre aux questions que pose la faisabilité d'un dispositif de détection d'explosifsà l'aide de la technologie de spectroscopie térahertz, cette thèse a exploré troisaxes. Le premier a consisté à établir une base de données des signatures spectrales (indiceet absorption) d'une large gamme de matériaux d'intérêt pour ce type d'applications,à partir des données expérimentales que nous avons mesurées par spectroscopie dans ledomaine temporel. Nous avons identifié les matériaux montrant une signature spectralesignificative et nous avons aussi étudié l'effet des matériaux de dissimulation.Dans la seconde partie de ce travail, nous avons conçu et construit un banc de spectroscopieultra-large bande destiné à une meilleure identification spectrale des substances. Nousavons identifié les limites techniques de ce type de banc et donné les pistes pour atteindreles performances désirées.Ensuite, nous avons développé et validé un banc de spectroscopie en réflexion, de typegoniométrique, afin de détecter des signaux térahertz diffusés par des matériaux hétérogènes.Finalement, nous avons étudié les plasmons de surface dans le domaine térahertz, en vuede la détection de très faibles quantités de matière.
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Sloss, Ian. "The effects of ethanol on memory and neuroplasticity in a vertebrate and an invertebrate model of learning." Thesis, University of Sussex, 2016. http://sro.sussex.ac.uk/id/eprint/65381/.
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Binge drinking is characterised by cycles of ethanol intoxication and withdrawal and is thought to be highly deleterious for the normal functioning of the nervous system. The behavioural and neurophysiological consequences of rapid escalation of blood alcohol concentration and subsequent withdrawal, and their effects on learning and memory and underlying neural circuitry can be studied in suitable animal models. Here, spatial and instrumental learning as well as hippocampal LTP were assessed in C57BL/6J mice for the effects of adolescent intermittent ethanol (AIE) and other ethanol treatments. AIE treatment did not impair spatial or non-spatial memory when tested in adulthood. However, if mice were trained whilst intoxicated during AIE treatment, spatial memory was impaired. Post-training injections of ethanol impaired performance in operant conditioning. A rapid rise and fall in ethanol concentration, prior to stimulation, blocked LTP induction in drug naïve hippocampal slices; an effect that was not seen if the ethanol concentration was gradually increased and decreased. Moreover, AIE treatment caused an NMDA receptor-dependent transient increase in hippocampal LTP. The second part of this study used a novel molluscan model Lymnaea stagnalis and demonstrated that high concentrations of ethanol blocked acquisition and retrieval of an associative memory. However, if acquisition occurred in the presence of ethanol then memory could also be retrieved under ethanol, demonstrating ethanol state dependency. By utilising the cerebral giant cells, a modulatory neuron type with known involvement in memory formation, it was found that ethanol reduced the tonic firing frequency as well as the peak-to-trough and half-width parameters of individual action potentials. The development of in vivo and in vitro ethanol treatment and test protocols, and the findings based on their use, open up new avenues for future systematic investigations on ethanol's effects on behaviour and underlying neural circuitry in both vertebrate and invertebrate model systems.
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Nikzad, Nadia. "Optimisation of a small-scale ultrafiltration system for separation of humic substances from surface water." Thesis, KTH, Kemiteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298358.
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Norrvatten är den fjärde största dricksvattenproducenten i Sverige. De producerar och distribuerar dricksvatten till 14 kommuner norr om Stockholm. Norrvatten har under en tid studerat alternativa processer för att optimera och öka produktionskapaciteten och effektiviteten i deras dricksvattenreningsverk vid Görvälnverket. I detta projekt har en pilotanläggning använts för att studera och optimera ett hybridprocessteg bestående av ett koagulerings- och ultrafiltreringssteg med syfte att avlägsna humusämnen från ytvatten. Effekten av pH, reaktionstid och olika matarvattenkvaliteter (Görväln, Fyrisån och sandfiltrat) analyserades genom en serie experiment utförda med pilotanläggningen. Den mest optimala placeringen av ett eventuellt ultrafiltreringssteg i reningsprocessen studerades även. Resultaten från experimenten påvisade att pH mellan 6.1 och 6.7 inte hade någon effekt på reningen av fDOM. Mer signifikanta skillnader i rening kunde observeras mellan de olika koaguleringsdoserna, vilket indikerar att denna parameter är viktigare än pH. Reaktionstiden hade ingen märkbar effekt på anläggningens reningseffektivitet. Däremot ökade transmembrantrycket tio gånger snabbare under experimenten med den kortare reaktionstiden. Dessa resultat antyder att de bildade flocken var mindre och därmed blev mer tätt packade i ultrafiltret vilket i sin tur lett till det snabbt ökande trycket i membranet. En avskiljning av minst 50 %, men inte mer än 60 %, av det ingående fDOM kunde uppnås med alla matarvatten utom sandfiltratet, som hade en reningseffektivitet på 18 %. Vattnet från Fyrisån visade sig vara en utmaning för anläggningen att hantera, då trycket snabbt byggdes upp i membranet vilket tyder på att anläggningen inte klarar för starkt förorenade vatten. Resultaten från sandfiltratexperimenten visade att ett ultrafiltreringssteg efter sandfiltren skulle kunna vara en möjlig placering av ultrafiltren. Ytterligare studier krävs dock för att med säkerhet kunna bestämma den mest optimala placeringen. Sammanfattningsvis visar resultaten från experimenten lovande tecken på att en ultrafiltreringsprocess är ett möjligt alternativ för att öka Norrvattens dricksvattenreningsverks effektivitet och kapacitet.<br>Norrvatten is the fourth largest drinking water producer in Sweden. They produce and distribute drinking water to 14 municipalities north of Stockholm. For some time, Norrvatten has studied alternative processes in order to optimise and increase the production capacity and efficiency of their drinking water treatment plant at Görvälnverket. In this project, a small-scale pilot plant has been used to study and optimise a coagulation and ultrafiltration hybrid process step in order to remove humic substances from surface water. The effect of pH, reaction time, and different feed water qualities (Görväln, Fyrisån and Görväln full scale sand filtrate) were analysed through a series of experiments performed with the pilot plant. The most optimal placement of an eventual ultrafiltration step was also studied. The results from the experiments suggested that pH in the range 6.1 to 6.7 had no large effect on the removal efficiency of fluorescent dissolved organic matter (fDOM). Instead, differences in removal efficiency could be observed between coagulant dosages which indicates that this parameter is of more importance than pH. At higher pH (> 7) removal was significantly lower. The reaction time had no effect on the removal efficiency of the plant. However, the transmembrane pressure increased ten times faster during the experiments with a shorter reaction time. These results suggested that the floc formed were smaller and thereby more tightly packed in the ultrafilter which in turn increased the pressure in the membrane. An fDOM removal of at least 50 %, though no more than 60 %, was achieved with all feed waters except for the sand filtrate which had a removal efficiency of 18 %. However, highly concentrated humic waters such as Fyrisån proved to be challenging for the plant to handle since the pressure built up rather quickly in the membrane. The sand filtrate feed water experiments indicated that an ultrafiltration step after a sand filtration process would be effective. However, further studies are required to be able to determine the most optimal placement of the ultrafiltration process. In conclusion, the results achieved with the pilot plant show promising signs of an ultrafiltration process being a viable alternative for Norrvatten to increase their drinking water treatment plant’s efficiency and capacity.
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Methling, Maximilian [Verfasser]. "Detection of psychoactive substances (antidepressants, antipsychotics, benzodiazepines, alcohol) in human hair and other matrices using liquid chromatography-mass spectrometry (LC-MS/MS) / Maximilian Methling." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1217251324/34.
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Lemee, Laurent. "Caractérisation structurale de la matière organique complexe des sols et des sédiments - Dynamique et réactivité -." Habilitation à diriger des recherches, Université de Poitiers, 2004. http://tel.archives-ouvertes.fr/tel-00131020.
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La structure et la dynamique de la matière organique mobile (lipides), peu soluble (acides humiques) et insoluble (humine et kérogène) ont été étudiés dans différents environnements. Les sols, les tourbes qui représentent la première phase d'accumulation du carbone organique (diagenèse précoce) et les sédiments anciens dans lesquels le carbone organique s'est transformé. L'étude de ces différents milieux pouvant permettre d'appréhender les mécanismes d'accumulation du carbone.<br />L'étude de la structure et de l'évolution de la matière organique des sols et des sédiments a nécessité la mise en œuvre de techniques d'analyse globales comme la spectroscopie infra-rouge ou la RMN 13C (CP-MAS) et plus approfondies comme la pyrolyse off line ou on line (Py-GC/MS). En fonction des informations obtenues, nous avons appliqué aux macromolécules biologiques, des réactions de dégradation plus sélectives par voie chimique ou enzymatique. Le développement ou l'adaptation de ces techniques et réactions de dégradation a donc constitué une large partie de ce travail.<br /> L'étude de la matière organique complexe des sols et des sédiments fait apparaître la présence de chaînes aliphatiques, liées au réseau macromoléculaire par des liaisons éther ou ester, ou formant des ponts dialkyles. L'importance des liaisons de faible énergie a pu être soulignée dans la structure des substances humiques ainsi que la contribution ligneuse. <br />L'accumulation du carbone dans les tourbes et les sédiments s'est déroulée en milieu anoxique (conditions réductrices), cependant il existe des témoins de phénomènes d'oxydation qui ont pu se produire au préalable ou lors d'échanges possibles avec une phase mobile.<br />L'étude des processus de biodégradation du carbone dans les sols montre que les molécules simples, après oxydation, peuvent s'incorporer dans le réseau macromoléculaire par liaisons ester ou éther. Nous avons ainsi montré que l'apport de carbone organique sur des sols cultivés en améliore les qualités.
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O'Connor, Eoin. "Investigations into the role of the metabotropic glutamate receptor, mGluR5, in incentive learning and some behavioural and neurobiological effects of cocaine." Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/6981/.
Full textAbstract:
The metabotropic glutamate receptor, mGluR5, is densely expressed in brain regions involved in incentive learning processes. There is considerable evidence to suggest that following exposure to addictive drugs such as cocaine, adaptations in these brain areas may underlie the development and maintenance of behavioural responses related to addictive processes. The present thesis examines the role of mGluR5 in both incentive learning processes and some behavioural and neurobiological effects of cocaine. First, using a novel mutant mouse line in which mGluR5 is selectively knocked down in cells that express dopamine D1 receptors (D1R), I argue that this mGluR5 population is critically important for specific incentive learning processes. By blocking mGluR5 in wild-type mice with a selective antagonist, I then propose mGluR5 as necessary for the acquisition, but not the expression of an incentive association. Next, I present data showing that mGluR5 on dopaminoceptive neurons are not necessary for the „conditioned rewarding‟ properties of cocaine, measured in the conditioned place preference model, but do contribute to the psychomotor activating effects of cocaine. Finally, I present an immunohistochemistry study that examines cocaine-induced activation of the extracellular-signal related kinase (ERK) pathway. In the mGluR5 knock-down mice, activation of the ERK pathway in the striatum is disrupted following an acute injection of cocaine. Given the importance of the ERK pathway in establishing and maintaining long term memories, I propose that disruption of this pathway could contribute, in part, to some findings reported in the present thesis. Taken together, this thesis will argue that signalling through mGluR5 on D1R expressing neurons is important for the formation of incentive associations, and may contribute to neural adaptations necessary for the development and maintenance of behavioural responses related to addictive processes.
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Rey, Aurélien. "Mise au point de méthodes pour l'analyse de substances critiques issues des rejets industriels et de la fabrication des produits de la filière cuir." Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-01068734.
Full textAbstract:
Dans le cadre de la protection de l'environnement et du consommateur, CTC effectue des tests enchimie analytique sur de nombreux paramètres en matrices aqueuses, cuir et textile. Les nouvelles substancesmises sur le marché ainsi que les réglementations évoluant sans cesse, le développement de nouvellesméthodes d'analyses est donc nécessaire.Plusieurs méthodes analytiques ont ainsi été développées. Pour l'analyse des rejets d'effluents industriels desinstallations classées et pour l'analyse d'innocuité de produits utilisant le cuir ou le textile (chaussures,maroquinerie, prêt-à-porter...).Les chloroalcanes ont été dosés en chromatographie gazeuse (GC) associée à la spectrométrie de masse (MS)utilisant l'ionisation chimique, à la fois en matrices aqueuses (limite de quantification, LQ, à 0,6 μg/l) et sur lescuirs (LQ à 2 mg/kg).Une analyse des alkylphénols et alkylphénols ethoxylates a été développée pour les matrices aqueuses parGC/MS (LQ à 0,05 μg/l).Plusieurs familles de retardateurs de flammes ont ensuite été étudiées. Les polybromodiphénylethers peuventêtre dosés dans les eaux (LQ<0,05 µl) et le cuir (LQ <= µg/kg), par GC/MS en ionisationchimique.L'hexabromocyclododécane et des organophosphates, par chromatographie liquide et spectrométrie de masseen tandem pour des matrices textiles (LQ à 6 mg/kg). Des hydrocarbures aromatiques polycycliques dans le cuir ont ensuite été analysés par GC/MS-MS (LQ à 250 μg/kg).Enfin, une méthode multirésidus portant sur plusieurs familles de micropolluants organiques a été mise aupoint en GC/MS pour les rejets d'effluents (LQ <0,1 µg/l)
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Cachet, Nadja. "Metabolites secondaires d'invertebres marins et biosynthese in vivo d'alcaloides d'Agelas oroides." Phd thesis, Université de Nice Sophia-Antipolis, 2009. http://tel.archives-ouvertes.fr/tel-00455200.
Full textAbstract:
Le groupe Substances Naturelles Marines du LCMBA (UMR 6001 CNRS-UNSA) se consacre à l'isolement et à la caractérisation de nouvelles molécules bioactives à partir d'invertébrés marins (spongiaires et cnidaires principalement). Suivant l'intérêt que ces molécules originales suscitent, leur valorisation peut concerner autant le domaine de la pharmaceutique que celui de la biosynthèse ou de l'écologie chimique. Ce manuscrit présente les travaux de recherche réalisés sur les deux éponges Pandaros acanthifolium et Agelas oroides, et sur les deux cnidaires Astroides calycularis et Parazoanthus axinellae. P. acanthifolium, très peu étudié, a permis l'isolement d'une nouvelle famille de saponines stéroïdiennes. La famille des orthidines et une nouvelle aplysinopsine, ont été isolées pour la première fois d'A. calycularis. Enfin, nous décrivons une nouvelle famille d'alcaloïdes isolée de P. axinellae qui nous a permis de distinguer deux morphotypes de P. axinellae d'après leurs profils chimiques. A. oroides a été choisi comme modèle d'étude pour la mise en place d'un nouveau protocole de biosynthèse in vivo des alcaloïdes de type pyrrole-2-aminoimidazoles (P2AI). Ces études permettent de confirmer l'utilisation de la proline dans la biosynthèse des P2AI.
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Dangleterre, Laëtitia. "Apport des spectroscopies moléculaires à l'étude des mécanismes de fixation d'ions métalliques polluants par les substances humiques.Complexation de Al(III), Pb(II) et Zn(II) par des systèmes modèles." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2007. http://tel.archives-ouvertes.fr/tel-00366217.
Full textAbstract:
Les substances humiques (SH) sont issues de la dégradation de résidus organiques et représentent la partie la plus importante de la matière organique des systèmes naturels. Les SH sont capables de piéger de nombreux polluants comme les métaux lourds et jouent donc un rôle majeur dans la rétention des ions métalliques. Leurs propriétés complexantes sont dues principalement à certaines fonctions récurrentes : les groupements carboxyliques et phénoliques.<br />Dans une 1ère partie, l'étude de la complexation de molécules modèles possédant des sites similaires à ceux rencontrés dans les biopolymères naturels a permis d'évaluer les capacités complexantes des fonctions les plus répandues (catéchol, hydroxy-carbonyle et acide carboxylique). L'association de techniques spectroscopiques et de calculs de chimie quantique a permis d'établir un classement des pouvoirs chélatants des composés mono-sites vis-à-vis des ions métalliques Al(III), Pb(II) et Zn(II)), et a montré que ce type de classement est conservé lorsque les sites sont en compétition au sein d'une même structure.<br />Dans une 2nde partie, l'examen par fluorescence synchrone de la complexation des 3 métaux polluants par un acide humique standard (AH) a mis en évidence des comportements différents pour chacun d'eux, reflétant des mécanismes de fixation distincts et une spécificité des interactions métallo-humiques. Nous avons ainsi pu établir un classement du pouvoir complexant de AH vis à vis des 3 cations, en accord avec celui obtenu pour les modèles. Enfin, la compétition entre AH et deux molécules organiques de faible poids moléculaires a montré que les pourcentages de polluants extraits de l'acide humique sont faibles et que celui-ci reste un véritable « réservoir toxique » au sein des milieux naturels.
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Agada, Otokpa Christopher-Marius. "Catalytic efficiency of zerovalent iron compounds as paint driers compared with conventional substances : the use of ferrocene and other iron compounds as driers in autoxidative paint systems at ambient and elevated temperatures." Thesis, University of Bradford, 1985. http://hdl.handle.net/10454/3543.
Full textAbstract:
Novel paint driers based on iron co-ordination complexes were investigated for use as stoving finishes in oil-based coatings. Cis 9, cis 12-octadecadienoic acid was employed as a model vehicle because of its high drying capacity. Iron compounds generally have low catalytic efficiency at low temperatures which however improve with rises in temperature. The catalytic efficiency of some iron compounds was compared with those of some conventional driers at room temperature; 60 C, 80 C and 1200 C. To make the results comparative, equal weights of drier (0.05%) metal were employed in one series of experiments. In another series, a much higher concentration (0.25%) metal based on the weight of 9,12-octadecadienoic acid was employed. Equal weights of drier combination(s) and variable drier weights were examined to determine synergism or antagonism in the autoxidative systems. Maximum oxygen absorption, changes in iodine and peroxide values were monitored to determine a comparative catalytic performance of the driers at the reaction temperatures used. The reactivity of iron co-ordination complexes was found to be influenced by the organic compound with which the iron is chelated. Zerovalent iron complexes can be employed as high temperature driers. For convenience some common names have been used for major chemicals of importance in this work, e. g., Linoleic acid; cis 9, cis 12-octadecadienoic acid. Ferrocene; dicyclopentadienyl iron.
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Brown, Jessica, and Lisa M. Whittington. "Positive Drug Screens for Methamphetamine and/or Cocaine Versus Other Substances of Abuse in Patients with Serious Mental Illnesses: Comparison of Polysubstance Abuse, Psychiatric Hospitalizations, Prescribed Psychotropic Medications, and Cost of Services." The University of Arizona, 2007. http://hdl.handle.net/10150/624324.
Full textAbstract:
Class of 2007 Abstract<br>Objectives: To identify differences between patients diagnosed with a serious mental illness who test positive for cocaine and/or methamphetamine compared to patients who test positive or other abused substances.
Methods: This retrospective study of clinical data obtained through a community mental health agency that provides outpatient services for patients with a serious mental illness. The study population was divided into two subgroups: positive cocaine and/or methamphetamine drug screen versus other positive drug screens and were compared over a 12- month period for the frequency and types of positive drug screens and blood alcohol levels, days of court-ordered treatment, the number of psychiatric hospitalizations and length of stay, primary psychiatric diagnosis, and the cost of care for services provided.
Results: More females were in the “cocaine/methamphetamine” group versus more males in the “other substances of abuse” group, (p < 0.01). A higher proportion of patients diagnosed with psychotic disorders tested positive for “other substances” than for “cocaine and methamphetamine” (p < 0.01) and the “cocaine/methamphetamine” group had significantly more mood and anxiety disorders than the other group (p < 0.05). The frequency of patients testing positive for marijuana, methadone, and other opiates was higher in the “other substance abuse” group (p < 0.001). Patients in the “cocaine/methamphetamine” group had higher rates of polysubstance abuse (p < 0.001). The most commonly abused substance was cocaine (53.8%).
Conclusions: Regular drug screening for substances of abuse and utilization of drug treatment programs should be recommended for SMI patients to improve their care and treatment outcomes.
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Agada, Otokpa C.-M. "Catalytic efficiency of zerovalent iron compounds as paint driers compared with conventional substances: The use of ferrocene and other iron compounds as driers in autoxidative paint systems at ambient and elevated temperatures." Thesis, University of Bradford, 1985. http://hdl.handle.net/10454/3543.
Full textAbstract:
Novel paint driers based on iron co-ordination complexes were
investigated for use as stoving finishes in oil-based coatings. Cis
9, cis 12-octadecadienoic acid was employed as a model vehicle because
of its high drying capacity. Iron compounds generally have low
catalytic efficiency at low temperatures which however improve with
rises in temperature.
The catalytic efficiency of some iron compounds was compared
with those of some conventional driers at room temperature; 60 C,
80 C and 1200 C. To make the results comparative, equal weights of
drier (0.05%) metal were employed in one series of experiments. In
another series, a much higher concentration (0.25%) metal based on
the weight of 9,12-octadecadienoic acid was employed.
Equal weights of drier combination(s) and variable drier
weights were examined to determine synergism or antagonism in the
autoxidative systems.
Maximum oxygen absorption, changes in iodine and peroxide
values were monitored to determine a comparative catalytic
performance of the driers at the reaction temperatures used.
The reactivity of iron co-ordination complexes was found to
be influenced by the organic compound with which the iron is chelated.
Zerovalent iron complexes can be employed as high temperature
driers.
For convenience some common names have been used for major chemicals
of importance in this work, e. g.,
Linoleic acid; cis 9, cis 12-octadecadienoic acid.
Ferrocene; dicyclopentadienyl iron.
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Som, Marie-Pierre. "ÉTUDE MOLÉCULAIRE DES COMPOSÉS ORGANIQUES DE COMPOSTFORMATION, TRANSFORMATION DANS LES SOLSACTION SUR LES PROPRIÉTÉS DES SOLS." Phd thesis, Université de Poitiers, 2006. http://tel.archives-ouvertes.fr/tel-00157336.
Full textAbstract:
Le but de cette étude était de caractériser à l'échelle moléculaire la maturité d'un compost de déchets verts et de biodéchets et son incorporation dans un sol.<br />Cinq nouveaux critères de maturité ont été déterminés par thermo-gravimétrie et thermochimiolyse. Cette technique permet d'observer l'augmentation de l'activité bactérienne (rapport acides ramifiés/linéaires et mono/diacides). De plus l'oxydation de composés triterpèniques dans les lipides est mise en évidence. L'évolution de la matière organique (MO) des substances humiques (SH) ne fait pas apparaître de lien direct avec les lipides libres.<br />L'apport de compost sur un sol instable augmente l'activité biologique améliorant ainsi sa stabilité structurale et limitant les risques d'érosion. Des marqueurs lipidiques du compost ont été suivis après épandage. L'incorporation de la MO du compost dans les SH est démontrée par l'augmentation du rapport acides ramifiés/linéaires et la présence d'omega-méthoxyesters.
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Coke, Christopher James. "Cannabinoid Receptor 2 and C-X-C Chemokine Receptor 4 Interact to Abrogate CXCL12-Mediated Cellular Response." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2017. http://digitalcommons.auctr.edu/cauetds/76.
Full textAbstract:
The expression of C-X-C Chemokine Receptor 4 (CXCR4) has been correlated with increased metastatic potential of cancer cells. CXCR4 increases tumor malignancy by encouraging tumors cells to migrate to distal organs expressing its cognate ligand, CXCL12, facilitating metastasis. Thus, targeting the CXCR4/CXCL12 signaling axis provides a good strategy to inhibit the metastatic spread of tumor cells and slow cancer progression. Various studies suggest that cannabis may have anti-proliferative as well as anti-metastatic properties, though a biochemical mechanism describing how this occurs has yet to be discovered. Our lab has confirmed that agonist-bound CXCR4 and agonist-bound Cannabinoid Receptor 2 (CB2) can form heterodimers that play a role in decreasing cancer cell migration. Simultaneous treatment of the breast cancer cell line, MDA-MB-231 and the prostate cancer cell line PC-3, with CXCL12 and AM1241, a synthetic ligand for CB2, desensitizes the intrinsic cellular response to migrate toward areas of high CXCL12 concentration. Furthermore, through co-immunoprecipitation and
proximity ligation assays (PLA), we have determined that there is increased interaction between the two receptors with co-stimulation of respective agonists, providing evidence for the therapeutic notion that treating tumors that endogenously secrete CXCL12 with exogenous ligands for the cannabinoid can induce dimerization. Moreover, when CXCR4 and CB2 were activated simultaneously with various agonists, decreases in migration were observed, confirming that the regulatory activity was receptor-based, not agonist-based. Finally, to determine whether simultaneously–treated, dimerized receptors inhibited activity of respective receptors, calcium mobilization assays to determine G-protein coupled receptor activation were employed. Results showed that transiently activated calcium levels were significantly lower in response to simultaneous treated cells when compared to cells treated with their individual ligands. Phosphorylation of ERK and AKT were abrogated in response to simultaneous stimulation indicating loss in downstream signaling. Therefore, we believe that the interaction of CB2 with CXCR4 may play a role in inhibiting the cells response to CXCL12, leading to a loss in metastatic potential of cells expressing these receptors.
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Niarchos, Georgios. "Electrodialytic Remediation of PFAS-Contaminated Soil." Thesis, KTH, Vatten- och miljöteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-239878.
Full textAbstract:
Per- and polyfluoroalkyl substances (PFASs) are a group of anthropogenic aliphatic compounds, widelyknown for their environmental persistence and toxicity to living beings. While they are ubiquitous in theenvironment, interest has been focused on contaminated soil, which can act as a primary recipient andsource of groundwater contamination. Electrokinetic technology is based on the movement of ionsunder the effect of an electric field. This could be a promising remediation solution, since PFASs areusually present in their anionic form. The contaminants can then be concentrated towards the anode,thus reducing a plume’s volume and possibly extracting the substances from soil. The preliminary aimof the present study was to evaluate the potential of using electrodialysis for the remediation of PFAScontaminatedsoil for the first time. Experiments were run with natural contaminated soil samples,originating from a fire-fighting training site at Arlanda Airport, and at Kallinge, Sweden, as well as inartificially spikedsoil. Electrodes were placed in electrolyte-filled chambers and separated by the soilwith ion-exchange membranes for pH-control. In total, five experiments were conducted. Two differentsetups were tested, a typical 3-compartment EKR cell and a 2-compartment setup, to allow for pHincrease and facilitate PFAS desorption. Two different current densities were tested; 0.19 mA cm-2 and0.38 mA cm-2. After twenty-one days, soil was cut in ten parts lengthwise and triplicate samples wereanalysed for PFAS concentrations, with HPLC-MS/MS. Sixteen out of the twenty-six screened PFASswere detected above MDL in the natural soil samples. The majority of the detected PFASs showed apositive trend of electromigration towards the anode, under both current densities, with only longerchainedcompounds (c>8) being immobile. This can be attributed to the stronger sorption potential oflong-chained PFAS molecules, as has been reported in previous sorption studies. Mass balancedistribution for a high current density (0.38 mA cm-2) experiment revealed that 73.2% of Σ26PFAS wasconcentrated towards the anode, with 59% at the soil closer to the anode, 5.7% at the anion exchangemembrane and 8.5% at the anolyte. It also showed higher mobility for short-chained molecules (c≤6),as they were the only compounds to be extracted from soil and be concentrated in the anolyte. Highercurrent densities were not directly correlated with higher electromigration rates, as to the lack of massbalance data for the low current density experiments. Regardless, electrodialysis could be a viable optionfor PFAS soil remediation and further research to encourage the understanding of the migrationmechanism, as well as combination with other treatment methods is encouraged.<br>Per- och polyfluoralkylsubstanser (PFAS) är en grupp av antropogena alifatiska föreningar, allmäntkända för sin miljöpåverkan och toxicitet för levande varelser. Medan de är allestädes närvarande imiljön har intresset varit inriktat på förorenad mark, som kan fungera som primär mottagare och källatill grundvattenförorening. Elektrokinetisk teknik är baserad på jonernas rörelse under effekten av ettelektriskt fält. Detta kan vara en lovande lösningsmedel, eftersom PFAS är vanligtvis närvarande i sinanjoniska form. Föroreningarna kan sedan koncentreras mot anoden, vilket reducerar en plums volymoch eventuellt extraherar ämnena från jorden. Det preliminära målet med den föreliggande studien varatt utvärdera potentialen att använda elektrodialys för sanering av PFAS-förorenad jord för förstagången. Experimenten kördes med naturliga förorenade jordprover, härrörande från enbrandbekämpningsplats vid Arlanda flygplats, och i Kallinge, Sverige, samt i konstgjort spikedsol.Elektroder placerades i elektrolytfyllda kamrar och separerades av jorden med jonbytesmembran förpH-kontroll. Totalt genomfördes fem experiment. Två olika inställningar testades, en typisk 3-facksEKR-cell och en 2-facksinställning, vilket möjliggör pH-ökning och underlättar PFAS-desorption. Tvåolika strömtätheter testades; 0,19 mA cm-2 och 0,38 mA cm-2. Efter tjugo dagar skärs jorden i tio delari längdriktningen och trippelprover analyserades för PFAS-koncentrationer, med HPLC-MS / MS.Sexton av de tjugosex screenade PFAS: erna detekterades över MDL i de naturliga markproverna.Majoriteten av de upptäckta PFAS-värdena visade en positiv trend av elektromigration mot anodenunder båda strömtätheten, varvid endast längre kedjiga föreningar (c> 8) var immobila. Detta kanhänföras till den starkare sorptionspotentialen hos långkedjiga PFAS-molekyler, vilket har rapporteratsi tidigare sorptionsstudier. Massbalansfördelning för ett experiment med hög strömtäthet (0,38 mA cm-2) visade att 73,2% av Σ26PFAS koncentrerades mot anoden, med 59% vid jorden närmare anoden, 5,7%vid anjonbytarmembranet och 8,5% vid anolyten. Det visade också högre rörlighet för kortkedjigamolekyler (c≤6), eftersom de var de enda föreningarna som skulle extraheras från jord och koncentrerasi anolyten. Högre strömtätheter var inte direkt korrelerade med högre elektromigrationshastigheter,avseende bristen på massbalansdata för experimenten med låg strömtäthet. Oavsett elektrodialys kandet vara ett lönsamt alternativ för PFAS-markrening och ytterligare forskning för att uppmuntraförståelsen för migrationsmekanismen, liksom kombinationen med andra behandlingsmetoder främjas.
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Alabbas, Alhumaidi B. "GLYCOSAMINOGLYCAN LYASES IN THE PREPARATION OF OLIGOSACCHARIDES." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5279.
Full textAbstract:
Glycosaminoglycans are heterogeneous polysaccharides that mediate important biological functions. There has been considerable interest in deciphering the precise GAG sequences that are responsible for protein interactions. In fact, several GAG oligosaccharides have been discovered to date as targeting proteins with higher level of specificity. Yet, it has been difficult to develop GAG oligosaccharides as drugs. One of the key reasons for this state of art is that GAG synthesis is extremely challenging and is highly structure-specific. Thus, much of the biology and pharmacology of GAG remains unknown and unexploited to date.
An alternative approach is to prepare GAG oligosaccharides using enzymatic depolymerization of polymeric GAGs. GAG lyases, including heparinases and chondritinases represent powerful tools that can theoretically generate multiple oligosaccharides in parallel. However, it is difficult to implement such procedures with high consistency. Moreover, GAG lyases can digest GAGs down to disaccharides. A priori, non-polymeric GAGs, or alternatively GAG oligosaccharides containing 4 to 10 residues, would be expected to function better as therapeutic agents because they would be more homogeneous and less non-specific than their polymeric precursors.
Thus, we reasoned that immobilization of these enzymes may engineer altered biopolymer processing, which may afford longer oligosaccharides in higher proportions and greater consistency. Heparinase-I and chondroitinase ABC were immobilized on CNBr-activated Sepharose and compared with the free form of the enzyme. Immobilized GAG lyases retained high efficiency of depolymerization over a wide range of pH, temperature and reusability. Most importantly, the immobilized enzyme was found to produce larger proportions of oligosaccharides longer than di- and tetra-saccharides as compared to lyases in the free form.
A two dimensional separation involves size exclusion chromatography followed by reversed phase ion-pairing ultra performance liquid chromatography coupled to electrospray ionization mass spectrometry was employed to separate and characterize oligosaccharide structures. We have identified 40 heparin oligosaccharides, including regular and rare structures ranging from dp4 to dp10 and 39 chondroitin sulfate oligosaccharides in high homogeneity and significant yields. Overall, this technology is likely to offer a simple and cost effective route to preparation of larger amounts of sequences that can be expected to bind and modulate protein function.
31
Minard, Corinne. "Doubles couplages de Suzuki-Miyaura sélectifs sur des dérivés dihalogénés symétriques - Application à la synthèse de la ningaline B et de ses analogues." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00919884.
Full textAbstract:
La recherche de nouvelles molécules à visée thérapeutique est un enjeu majeur pour la communauté scientifique et actuellement, 60% des médicaments utilisés cliniquement sont des produits naturels ou leurs analogues. Dans ce contexte, afin d'être capable de générer rapidement une bibliothèque de composés, le développement d'outils de synthèse efficaces est fondamental et c'est dans cette optique que s'inscrit le travail mené au cours de cette thèse. Les produits d'origine marine sont une source d'inspiration considérable dans le domaine de la création de nouveaux médicaments. Lors de ce travail, une attention particulière a été accordée à la ningaline B et à ses analogues avec pour objectif de mettre au point une voie d'accès simple et efficace. En effet, si la capacité de la forme hexaméthyléther à reverser la résistance aux anticancéreux par inhibition de la glycoprotéine-P a déjà été rapportée dans la littérature, l'étude d'analogues n'a été que peu exploitée.Dans ce contexte, une voie de synthèse reposant sur une étape clé de double couplage de Suzuki-Miyaura sur un dérivé (pseudo)dihalogéné symétrique a été proposée. Cette étape a fait l'objet d'une étude approfondie en envisageant deux approches. La première approche, basée sur des travaux antérieurs réalisés au laboratoire, a été de type simultané. Ainsi, à la manière d'une réaction multicomposante, tous les réactifs sont introduits dès le départ dans le milieu réactionnel. Cette méthode a montré des résultats intéressants dans le cas où deux dérivés borés électroniquement différents sont employés. En revanche, il a été montré que l'utilisation d'espèces borés électroniquement similaires était peu viable avec l'obtention d'un mélange statistique en produits de dicouplage. Toutefois, la préparation des cibles visées requérant l'utilisation d'aryles borés riches en électrons, une autre approche, séquentielle, a été envisagée. Après un travail d'optimisation sur des substrats simplifiés, avec pour objectif de disposer de conditions efficaces, adaptables, faciles avec des réactifs standards, une méthode de monoarylation de dérivés (pseudo)dihalogénés symétriques a été mise en place. Le champ d'application a ensuite été élargi en incluant les noyaux pyrroles nécessaires à la synthèse de la ningaline B et de ses dérivés. Ces travaux ont permis d'accéder aux molécules ciblées. En effet, une fois, les teraryles préparés, quelques étapes de manipulations fonctionnelles permettront d'avoir rapidement accès à de nombreux analogues. D'autre part, les motifs pouvant être obtenus par ce type de séquence réactionnelle pourraient être facilement dérivatisables afin de générer une bibliothèque d'analogues.
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Chorley, Paul. "The influence of dopamine on prediction, action and learning." Thesis, University of Sussex, 2012. http://sro.sussex.ac.uk/id/eprint/39650/.
Full textAbstract:
In this thesis I explore functions of the neuromodulator dopamine in the context of autonomous learning and behaviour. I first investigate dopaminergic influence within a simulated agent-based model, demonstrating how modulation of synaptic plasticity can enable reward-mediated learning that is both adaptive and self-limiting. I describe how this mechanism is driven by the dynamics of agentenvironment interaction and consequently suggest roles for both complex spontaneous neuronal activity and specific neuroanatomy in the expression of early, exploratory behaviour. I then show how the observed response of dopamine neurons in the mammalian basal ganglia may also be modelled by similar processes involving dopaminergic neuromodulation and cortical spike-pattern representation within an architecture of counteracting excitatory and inhibitory neural pathways, reflecting gross mammalian neuroanatomy. Significantly, I demonstrate how combined modulation of synaptic plasticity and neuronal excitability enables specific (timely) spike-patterns to be recognised and selectively responded to by efferent neural populations, therefore providing a novel spike-timing based implementation of the hypothetical ‘serial-compound' representation suggested by temporal difference learning. I subsequently discuss more recent work, focused upon modelling those complex spike-patterns observed in cortex. Here, I describe neural features likely to contribute to the expression of such activity and subsequently present novel simulation software allowing for interactive exploration of these factors, in a more comprehensive neural model that implements both dynamical synapses and dopaminergic neuromodulation. I conclude by describing how the work presented ultimately suggests an integrated theory of autonomous learning, in which direct coupling of agent and environment supports a predictive coding mechanism, bootstrapped in early development by a more fundamental process of trial-and-error learning.
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Davies, Rachel A. "Structure-Activity Relationship Studies of Synthetic Cathinones and Related Agents." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/5953.
Full textAbstract:
Synthetic cathinones and related agents represent an international drug abuse problem, and at the same time an important class of clinically useful compounds. Structure-activity relationship studies are needed to elucidate molecular features underlying the pharmacology of these agents. Illicit methcathinone (i.e., MCAT), the prototype of the synthetic cathinone class, exists as a racemic mixture. Though the differences in potency and target selectivity between the positional and optical isomers of synthetic cathinones and related agents have been demonstrated to have important implications for abuse and therapeutic potential, the two MCAT isomers have never been directly compared at their molecular targets: the monoamine transporters (MATs). Additionally, previous studies have found that the carbonyl oxygen atom can be replaced with a methoxy group, but this results in two chiral centers (i.e., four possible optical isomers for synthesis and evaluation). Here, the individual isomers of MCAT, their racemate, and achiral MCAT analogs were prepared where necessary, and examined in vitro and in silico at the MATs. All agents were active as substrates, with a rank order of potency suggesting that α-position chirality, in either configuration, is favored but not required, with the S(-) configuration slightly preferred. Either chiral center removal approach resulted in a reduction in potency, suggesting both favorable interactions with the α-methyl, and limited bulk tolerance. To further investigate this possibility, docking studies were conducted using homology models of the MATs. Common binding modes were identified that were similar to the binding mode of S(+)amphetamine co-crystallized at drosophila DAT. Taken together, these studies supported our conclusions, as steric hindrance was observed in the α-methyl region of the proposed binding site for the R(+)MCAT isomer.
Inclusion of the original synthetic cathinones among Schedule I controlled substances has driven the clandestine development of a second generation of agents, resulting in an array of new synthetic cathinones diverse in structure and effect.Pyrrolidinophenones are a major constituent of second-generation bath salts. Little is known about their structure-activity relationships. Here, we have synthesized and examined a series of aryl-substituted pyrrolidinophenone analogs, as well as an achiral pyrrolidinophenone analog, utilizing novel synthetic chemistry and an innovative cell-based epifluorescence Ca2+ imaging technique. Herein, we evaluated the neurochemical properties of these novel compounds at the dopamine transporter (DAT), considered to exert a major role in actions of drugs of abuse.
For future structure-activity relationship studies, additional analogs of synthetic cathinone-related agents were produced using novel synthetic approaches, including analogs and isomers of known amphetamine drugs of abuse.
Finally, though much has been learned about the role of the dopamine and serotonin transporters in the mechanisms of action of synthetic cathinones, the role of the norepinephrine transporter is poorly understood. Homology models of the human norephinephrine transporter were built and docking studies conducted to inform the study of MAT ligand selectivity, activity, and binding.
In conclusion, these studies represent progress towards the establishment of comprehensive structure-activity relationships for synthetic cathinones and related agents. Particular emphasis was placed on the SAR of the phenylalkylamine α-carbon in the synthetic cathinone context, and the role of the norepinephrine transporter in their activity.
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Dong, Huy Quang. "Evaluation du risque d'inflammation des fumées riches dans un milieu confiné sous-ventilé à l'aide de la simulation numérique." Phd thesis, ISAE-ENSMA Ecole Nationale Supérieure de Mécanique et d'Aérotechique - Poitiers, 2013. http://tel.archives-ouvertes.fr/tel-00954471.
Full textAbstract:
Un des objectifs a consisté à développer une étude systématique des caractéristiques d'allumage, depropagation et de combustion massique de combustibles liquides. La ré-inflammation des fumées riches estplus spécialement pris en compte. La recherche porte essentiellement sur les propriétés des feux dans uneenceinte avec ventilation contrôlée, sous ventilée. Les facteurs dominants à la ré-inflammation des fuméesriches est la quantité minimale d'hydrocarbures totaux et la température. Grâce à la Simulation Numériquedes Grandes Echelles, nous sommes allés à un niveau de détail permettant de prendre en compte l'influencede la ventilation sur la propagation de la flamme en milieu confiné. Les modèles numériques permet deprévoir les aspects aussi bien chimiques de la combustion (pyrolyse du combustible liquide, réaction dans laflamme), que thermodynamiques (transfert de chaleur et de masse flamme-liquide). L'enjeu est de concevoirun modèle de feu encore plus général, capable de traiter aussi les feux à grande échelle. Ce type de modèleest consacré à la mise en équations du problème et à la faisabilité d'une simulation numérique complexe.Les résultats obtenus sur les feux sur-ventilés sont en accord avec les résultats expérimentaux. Outre lesdifficultés théoriques de ce type de problème, il faut ajouter les difficultés pratiques liées à la durée trèsimportante des simulations sur ordinateur, et le coût de calcul élevé.
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Mendoza, Clément. "Caractérisation et comportement sous irradiation de phases powellites dopées terres rares : applications au comportement à long terme de matrices de confinement de déchets nucléaires." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00707843.
Full textAbstract:
Ce travail porte sur le comportement sous irradiation d'une vitrocéramique élaborée par traitement thermique d'une version riche en molybdène du verre de confinement de déchets nucléaires R7/T7 et plus particulièrement de la phase cristalline. Des terres rares (Nd3+ et Eu3+) sont utilisées à la fois comme simulants des produits de fission et des actinides mineurs et comme sondes structurales luminescentes. La phase cristalline présente dans ce type de vitrocéramique est un molybdate de calcium de type powellite CaMoO4 ayant incorporé divers éléments dont des terres rares. Les propriétés cristallochimiques de la phase powellite ont été étudiées notamment par spectroscopie Raman et photoluminescence grâce à divers échantillons naturels et céramiques de compositions allant de CaMoO4 à une modèle proche de celle des cristaux de la vitrocéramique : Ca0,76Sr0,1Na0,07Eu0,01La0,02Nd0,02Pr0,02MoO4. La largeur à mi-hauteur de la bande Raman à 880 cm-1 augmente linéairement en fonction du taux d'incorporation sur le site calcium, incorporation qui influe également sur les paramètres de maille. Le volume intrinsèque de la maille augmente ainsi de 2 %. L'étude d'analogues naturels contenant de l'uranium ainsi que de céramiques et vitrocéramiques irradiées aux ions hélium, argon et plomb a permis de montrer que la structure powellite était très résistante aux dégâts causés. Sous irradiation, le signal de luminescence de Eu3+ des différents échantillons tend à s'uniformiser. Cette uniformisation du signal se retrouve également en spectroscopie Raman. Alors qu'elle peut varier entre 6 et 12 cm-1 pour des céramiques saines, la largeur à mi-hauteur de la bande Raman à 880 cm-1 devient identique, de l'ordre de 18 cm-1, à partir de 10 dpa. Le désordre créé par les irradiations prend le pas sur celui créé par l'incorporation d'éléments dans la structure. Cependant, la spectroscopie Raman et la diffraction des rayons X montre que la structure reste cristalline, au moins partiellement. Sous irradiations, le gonflement de la powellite est en moyenne de 5 % mais est très hétérogène.
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Panza, Fabien. "Développement de la spectrométrie gamma in situ pour la cartographie de site." Electronic Thesis or Diss., Strasbourg, 2012. http://www.theses.fr/2012STRAE043.
Full textAbstract:
La spectrométrie gamma à haute résolution offre un outil d’analyse performant pour effectuer des mesurages environnementaux. Dans le cadre de la caractérisation radiologique d’un site (naturelle ou artificielle) ainsi que pour le démantèlement d’installations nucléaires, la cartographie des radionucléides est un atout important. Le principe consiste à déplacer un spectromètre HPGe sur le site à étudier et, à partir des données nucléaires et de positionnements, d’identifier, de localiser et de quantifier les radionucléides présents dans le sol. Le développement de cet outil fait suite à une intercomparaison où un exercice orienté intervention a montré les limites des outils actuels. Une partie de ce travail s’est portée sur la représentation cartographique des données nucléaires. La connaissance des paramètres d’un spectre in situ a permis la création d’un simulateur modélisant la réponse d’un spectromètre se déplaçant au-dessus d’un sol contaminé. Ce simulateur a lui-même permis de développer les algorithmes de cartographie et de les tester dans des situations extrêmes et non réalisables. Ainsi, ce travail ouvre sur la réalisation d’un prototype viable donnant en temps réel les informations nécessaires sur l’identité et la position possible des radionucléides. La recherche réalisée sur la déconvolution des données permet de rendre en post traitement une carte de l’activité du sol par radionucléide mais également une indication sur la profondeur de la source. Le prototype nommé OSCAR (Outil Spectrométrique de Cartographie de Radionucléides) a ainsi été testé sur des sites contaminés (Suisse et Japon) et les résultats obtenus sont en accord avec des mesures de référence<br>The high-resolution gamma spectrometry currently provides a powerful analytical tool for performing environmental measurements. In the context of radiological characterization of a site (natural or artificial radioactivity) and for the dismantling of nuclear installations, mapping of radionuclides is an important asset. The idea is to move a HPGe spectrometer to study the site and from nuclear and position data, to identify, to locate and to quantify the radionuclides present in the soil. The development of this tool follows an intercomparaison (ISIS 2007) where an intervention / crisis exercise showed the limits of current tools. The main part of this research project has focused on mapping of nuclear data. Knowledge of the parameters of an in situ spectrum helped to create a simulator modeling the response of a spectrometer moving over contaminated soil. The simulator itself helped to develop algorithms for mapping and to test them in extreme situations and not realizable. A large part of this research leads to the creation of a viable prototype providing real-time information concerning the identity and locality as possible radionuclides. The work performed on the deconvolution of data can make in post processing a map of the activity of radionuclide soil but also an indication of the depth distribution of the source. The prototype named OSCAR was tested on contaminated sites (Switzerland and Japan) and the results are in agreement with reference measurements
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Larabi, Islam Amine. "Nouveaux produits de synthèse : analyse, consommation et métabolisme ; Applications cliniques et médicolégales Rapid and simultaneous screening of new psychoactive substances and conventional drugs of abuse. A comparative study of Biochip Array Technology versus LC-MS/MS in whole blood and urine Development of a sensitive untargeted liquid chromatography– high resolution mass spectrometry screening devoted to hair analysis through a shared MS2 spectra database: A step toward early detection of new psychoactive substances Validation of an UPLC-MS/MS method for the determination of sixteen synthetic cannabinoids in human hair. Application to document chronic use of JWH-122 following a non-fatal overdose Development and validation of liquid chromatography-tandem mass spectrometry targeted screening of 16 fentanyl analogs and U-47700 in hair: Application to 137 authentic samples Prevalence and Surveillance of Synthetic Cathinones Use by Hair Analysis: An Update Review Prevalence of New Psychoactive Substances(NPS) and conventional drugs of abuse (DOA) in high risk populations from Paris(France) and its suburbs A cross sectional study by hair testing(2012–2017) Evaluation of drug abuse by hair analysis and self-reported use among MSM under PrEP: Results from a sub-study of the ANRS-IPERGAY trial. Hair testing for 3‑fluorofentanyl, furanylfentanyl, methoxyacetylfentanyl, carfentanil, acetylfentanyl and fentanyl by LC–MS/MS after unintentional overdose Drug‐facilitated sexual assault (DFSA) involving 4‐methylethcathinone (4‐MEC),3,4‐Methylenedioxypyrovalerone (MDPV), and doxylamine highlighted by hair analysis Metabolic Profiling of Deschloro-N-ethyl-ketamine (O-PCE) and identification of new target metabolites in urine and hair using human liver microsomes and high-resolution accurate mass spectrometry." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL029.
Full textAbstract:
L’objectif de ce travail a été de développer deux approches analytiques dédiées à l’analyse toxicologique des nouveaux produits de synthèse (NPS) dans différentes matrices biologiques (sang, urine et cheveux). La première est basée sur le criblage non ciblé par chimiluminescence sur biopuces et chromatographie liquide couplée à la spectrométrie de masse haute résolution (LC-HRMS) et la deuxième correspond à un criblage ciblé par spectrométrie de masse en tandem (LC-MS/MS). Ces deux approches ont ensuite été appliquées dans des études observationnelles pour évaluer la consommation de NPS dans des populations à risques de surdosage, de pharmacodépendance ou de soumission chimique dans un contexte clinique ou médico-judiciaire.La dernière partie a été consacrée au développement d’un nouvel outil analytique de traitement des données issues de la LC-HRMS qui a permis d’étudier le métabolisme de 9 NPS in vitro sur des cultures de microsomes du foie humain (HLM) et in vivo sur des échantillons biologiques d’usagers de ces drogues. Cette dernière approche a permis la création d’une bibliothèque de spectres de haute résolution composée de 228 métabolites dont certains ont été proposés comme marqueurs pertinents d’exposition aux NPS dont ils sont issus.Ce travail a été concrétisé par la rédaction de 10 publications scientifiques et a permis d’initier plusieurs collaborations pluridisciplinaires<br>The aim of the present work was to develop two analytical approaches dedicated to the analysis of new psychoactive substances in different biological matrices (blood, urine and hair). The first approach is based on untargeted screening by both biochip array technology chemiluminescence assay and liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) and the second corresponds to a targeted screening by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). These two approaches were then applied in observational studies to assess the consumption of NPS in high risk populations (overdose, drug abuse, drug facilitated crimes) in clinical and forensic settings. The last part of the work was devoted to the development of a new analytical tool for LC-HRMS data processing which made it possible to study the metabolism of 9 NPS In vitro on human liver microsomes (HLM) and In vivo in biological samples from drug users. This approach has enabled the creation of HRMS spectral library containing 228 metabolites, some of which have been proposed as relevant markers of NPS exposure.This work has resulted on 10 scientific publications and allowed to initiate many multidisciplinary collaborations
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Ngouana, wakou Brice Firmin. "Modélisation moléculaire de l'hydratation, de la structure, et de la mobilité des ions et de l'eau dans l'espace interfoliaire et à la surface d'une argile smectitique." Phd thesis, Ecole des Mines de Nantes, 2014. http://tel.archives-ouvertes.fr/tel-01002256.
Full textAbstract:
L'étude de l'adsorption et de la mobilité des ions dans les argiles est importante pour mieux appréhender de nombreux processus géochimiques et environnementaux, de même que pour prédire le comportement des radionucléides dans les conditions du stockage géologique. A cause de leurs tailles très petites (< 2μm), il n'est pas toujours évident d'étudier les argiles à l'aide des méthodes et techniques expérimentales existantes. L'une des alternatives à ce problème consiste alors à utiliser la modélisation moléculaire pour les étudier. En plus de leurs tailles fines, les argiles présentent également des structures complexes, qui peuvent survenir en raison de la multiplicité de possibilités de distributions et d'arrangements des substitutions isomorphiques dans leurs couches. Il a été clairement démontré qu'il existe une corrélation entre la distribution des substitutions dans les couches des argiles et les propriétés de ces dernières. En revanche, ceci reste à démontrer en ce qui concerne l'arrangement de ces substitutions dans les couches de l'argile. Dans ce travail, la modélisation moléculaire est utilisée pour déterminer et comparer les propriétés d'hydratation, ainsi que la structure et la mobilité des ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Ni²⁺, UO₂²⁺) et de l'eau dans l'espace interfoliaire de trois modèles de montmorillonite, différents entre eux par l'arrangement des substitutions isomorphiques dans les couches de l'argile.L'adsorption et la diffusion des cations cités plus haut et de l'eau sont également étudiées à la surface de la montmorillonite et les résultats sont comparés à ceux obtenus dans l'espace interfoliaire à 298 K et à 363 K. Les résultats obtenus dans ce travail s'accordent bien avec les observations expérimentales, et font ressortir une corrélation plus ou moins importante entre le modèle d'argile utilisé et le type de propriété calculée. Cette corrélation dépend également de la nature du cation présent dans la structure de la montmorillonite et de sa teneur en eau.
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Martin-Burtart, Nicolas. "Développement d'algorithmes d'analyse spectrale en spectrométrie gamma embarquée." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00869554.
Full textAbstract:
Jusqu'au début des années 1980, la spectrométrie gamma aéroportée a avant tout été utilisée pour des applications géophysiques et ne concernait que la mesure des concentrations dans les sols des trois radionucléides naturels (K40, U238 et Th232). Durant les quinze dernières années, un grand nombre de dispositifs de mesures a été développé, la plupart après l'accident de Tchernobyl, pour intervenir en cas d'incidents nucléaires ou de surveillance de l'environnement. Les algorithmes développés ont suivi les différentes missions de ces systèmes. La plupart sont dédiés à l'extraction des signaux à moyenne et haute énergie, où les radionucléides naturels (K40, les chaînes U238 et Th232) et les produits de fission (Cs137 et Co60 principalement) sont présents. A plus basse énergie (< 400 keV), ces méthodes peuvent toujours être utilisées mais les particularités du fond de diffusion, très intense, les rendent peu précises. Cette zone énergétique est importante : les SNM émettent à ces énergies. Un algorithme, appelé 2-fenêtres (étendu à 3), a été développé permettant une extraction précise et tenant compte des conditions de vol. La surveillance du trafic de matières radioactives dans le cadre de la sécurité globale a fait son apparition depuis quelques années. Cette utilisation nécessite non plus des méthodes sensibles à un élément particulier mais des critères d'anomalie prenant en compte l'ensemble du spectre enregistré. Il faut être sensible à la fois aux radionucléides médicaux, industriels et nucléaires. Ce travail a permis d'identifier deux familles d'algorithmes permettant de telles utilisations. Enfin, les anomalies détectées doivent être identifiées. La liste des radionucléides nécessitant une surveillance particulière, recommandée par l'AIEA, contient une trentaine d'émetteurs. Un nouvel algorithme d'identification a été entièrement développé, permettant de s'appuyer sur plusieurs raies d'absorption par élément et de lever les conflits d'identification.
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Tyrpekl, Vaclav. "Effet matériaux lors de l'interaction corium-eau : analyse structurale des débris d'une explosition vapeur et mécanismes de solidification." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00758983.
Full textAbstract:
Ce travail a été réalisé en cotutelle entre l'Université Charles à Prague (République Tchèque) et l'Université de Strasbourg (France). Il a également profité d'une coopération entre l'Institut de Chimie Inorganique de l'Académie des Sciences de République Tchèque et le Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA, Cadarache, France). Les résultats des travaux ont contribué au projet OCDE / AEN Serena 2 (Programme portant sur l'étude des effets d'une explosion de vapeur dans un réacteur nucléaire à eau). La thèse présentée se situe dans le domaine de la sûreté nucléaire et de la science des matériaux. Elle traite de l'Interaction Combustible-Réfrigérant (ICR, ou FCI en anglais pour Fuel-Coolant Interaction) susceptible d'intervenir lors d'un accident grave de réacteur nucléaire et actuellement à l'étude dans les programme de R&D. Au cours d'un accident de fusion d'un coeur de réacteur, les matériaux fondus peuvent interagir avec le liquide de refroidissement (eau légère), aussi appelé réfrigérant. Cette interaction peut se produire à l'intérieur de la cuve ou, en cas de rupture de celle-ci, à l'extérieur. Ces deux scénarios sont couramment appelés Interaction Combustible-Réfrigérant en- et hors- cuve et se distinguent de par les conditions du réacteur lors de l'accident : pression du système, degré de sous refroidissement de l'eau, etc. L'interaction entre le combustible fondu et le liquide de refroidissement peut évoluer vers une détonation thermique appelée "explosion de vapeur" qui peut endommager le réacteur, voire compromettre l'intégrité du confinement. Des expériences récentes ont montré que la composition du combustible a un effet majeur sur l'apparition et le rendement d'une telle explosion. En particulier, des comportements différents ont été observés entre un matériau simulant, l'alumine, qui explose très facilement, et diverses compositions de corium prototypique (80 m. % UO2, 20% m.% ZrO2). Cet "effet matériau" a suscité un intérêt nouveau pour les analyses post-expériences des débris issus de l'ICR afin de déterminer les mécanismes qui interviennent au cours de ces phénomènes extrêmement rapides. La thèse est organisée en neuf chapitres. Le chapitre 1 constitue une introduction générale et présente le contexte d'un accident grave d'un réacteur nucléaire. Quelques exemples d'accidents graves (Three Miles Island 1979, Tchernobyl 1986 et Fukushima 2011) sont brièvement abordés. Le chapitre 2 résume les aspects théoriques de l'interaction combustible-réfrigérant. Il est divisé en quatre parties correspondant aux quatre étapes généralement rencontrées lors du mécanisme d'ICR i) Prémélange - le combustible fondu, versé dans l'eau, se fragmente en gouttelettes grossières qui s'isolent d'un film de vapeur. ii) Déclenchement - le film de vapeur entourant les gouttes de combustible est déstabilisé, permettant ainsi la fragmentation fine du combustible. iii) Propagation - la fragmentation du combustible se propage à l'ensemble du prémélange, augmentant ainsi la surface de contact entre le combustible fondu et l'eau. Ceci conduit à une production intense de vapeur à grande échelle. iv) Expansion (explosion) - l'énergie thermique transférée du combustible à l'eau est transformée en travail mécanique de la vapeur.[...]
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Panza, Fabien. "Développement de la spectrométrie gamma in situ pour la cartographie de site." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00975929.
Full textAbstract:
La spectrométrie gamma à haute résolution offre un outil d'analyse performant pour effectuer des mesurages environnementaux. Dans le cadre de la caractérisation radiologique d'un site (naturelle ou artificielle) ainsi que pour le démantèlement d'installations nucléaires, la cartographie des radionucléides est un atout important. Le principe consiste à déplacer un spectromètre HPGe sur le site à étudier et, à partir des données nucléaires et de positionnements, d'identifier, de localiser et de quantifier les radionucléides présents dans le sol. Le développement de cet outil fait suite à une intercomparaison où un exercice orienté intervention a montré les limites des outils actuels. Une partie de ce travail s'est portée sur la représentation cartographique des données nucléaires. La connaissance des paramètres d'un spectre in situ a permis la création d'un simulateur modélisant la réponse d'un spectromètre se déplaçant au-dessus d'un sol contaminé. Ce simulateur a lui-même permis de développer les algorithmes de cartographie et de les tester dans des situations extrêmes et non réalisables. Ainsi, ce travail ouvre sur la réalisation d'un prototype viable donnant en temps réel les informations nécessaires sur l'identité et la position possible des radionucléides. La recherche réalisée sur la déconvolution des données permet de rendre en post traitement une carte de l'activité du sol par radionucléide mais également une indication sur la profondeur de la source. Le prototype nommé OSCAR (Outil Spectrométrique de Cartographie de Radionucléides) a ainsi été testé sur des sites contaminés (Suisse et Japon) et les résultats obtenus sont en accord avec des mesures de référence.
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Kubáň, Pavel. "Determination of ions and other low molecular substances by separation methods." Doctoral thesis, 2001. http://www.nusl.cz/ntk/nusl-86690.
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Murdock, Kathryn J. "Possible Terrestrial Basaltic Analogs for Highly Magnetized Martian Crustal Rocks." 2009. https://scholarworks.umass.edu/theses/342.
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Mars was assumed to be very similar to Earth in terms of topography, water, magnetic field, and even the existence of life. However, exploration of the planet in the 1960s by the Mariner missions showed us a very different planet, one very unlike our own. The later discovery by the Mars Global Surveyor (MGS) of the lack of a globally generated magnetic field proved just how different Mars is from Earth. The discovery of strong magnetic remanence (on the order of 20 – 30 A/m) on Mars implies that at some point in Mars’ history there was a magnetic field, and therefore a dynamo. Since a globally active magnetic field is not present, it can also be assumed that the dynamo ceased generation. Basaltic rocks on Earth typically have magnetic remanences between 1 to 4 A/m and do not usually hold on to those remanences for billions of years. In this study, I utilized the information available on the geochemistry, age, and magnetics of Martian rocks in an attempt to find appropriate terrestrial analogs. Seven Earth locations of basaltic rocks (Mauna Loa, Hawaii; Eldgja and Laki eruptions, Iceland; Springerville volcanic complex, Arizona; Taos Plateau volcanic complex, New Mexico; Lascar Volcano, Chile; Tatara-San Pedro volcanic complex, Chile; Patagonia slab window, Argentina) were selected with different tectonic environments, ages, and geochemistries and their rock magnetic properties including natural remanent magnetization (NRM), susceptibility, and hysteresis properties including coercivity were analyzed.
Geochemical values were plotted as averages on a silica vs. alkali graph. There was some variation in NRM and susceptibility values for each of the terrestrial locations (such as Taos Plateau), but overall the averages are a good representation of average NRM and susceptibility. None of the samples studied displayed high remanence, high susceptibility, and high coercivity that would indicate stable single-domain magnetite. Although vastly different basalt origins were studied, an analog to the highly magnetized Martian crust was not found. There are three possibilities for this. 1) A basaltic terrestrial analog does exist, yet it was not included in this study. This is a very viable possibility since there are basalts all over the Earth each with a unique origin. 2) A basaltic terrestrial analog does not exist because although the rocks on Mars are basaltic, the global magnetic field that existed billions of years ago on Mars was unlike that of Earth. Recent work (Stanley et al, 2008) has shown that the Martian magnetic field might be completely different from Earth’s, and therefore a terrestrial analog would be impossible to find. 3) A basaltic terrestrial analog does not exist, but a terrestrial analog of a different rock type does exist. The assumption that the surface rocks on Mars – which are known to be mostly basaltic – are the carrier of the high magnetism. There is the possibility that the surface may be the origin of the magnetism, and in the areas of extremely high magnetism the rocks might locally be different. Also, it may not be the surface rocks that are exhibiting the magnetism. It may be buried highly magnetic rocks under a basalt lava flows.
In addition to seeking out other basalts as terrestrial analogs for to the highly magnetized Martian rocks, it would also be worthwhile to investigate the possibility of a different magnetic field for Mars and what other terrestrial rocks could display such high magnetism billions of years after the termination of the Martian magnetic field.
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Martins, Maria João da Costa. "Toxicity of mistures of cocaine and often co-consumed substances." Master's thesis, 2016. https://repositorio-aberto.up.pt/handle/10216/87068.
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Martins, Maria João da Costa. "Toxicity of mistures of cocaine and often co-consumed substances." Dissertação, 2016. https://repositorio-aberto.up.pt/handle/10216/87068.
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Polónia, Maria Luís Morais. "Coffee consumption habits of portuguese adolescents and their association with the use of other psychoactive substances." Master's thesis, 2020. http://hdl.handle.net/10400.14/33626.
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Coffee is a psychoactive substance due to being a major source of caffeine. Adolescence is a developmental period where individuals might experiment and continue to use licit and illicit psychoactive substances. Evidence also suggests an association between coffee consumption and the use of other psychoactive substances. The study’s aims were to determine the coffee consumption patterns of Portuguese adolescents and to evaluate the association between coffee consumption and the use of tobacco, alcohol, and cannabis in the same sample. The results showed that coffee consumption in adolescence can have its origins in an individual’s childhood; a large number of adolescents frequently consumes coffee; adolescents prefer to consume caffeinated coffee over decaffeinated coffee; and coffee’s taste, the taste of coffee beverages, and coffee’s psychoactive effects are the main reasons for coffee consumption in adolescence. No significant differences were found for coffee consumption before the pandemic and during the pandemic’s emergency social distancing measures. Lastly, no significant associations were found between coffee consumption and the use of tobacco, alcohol, and cannabis. Future research could extend on the present study’s limitations and investigate coffee separated from the other caffeinated products. Practical implications relate to the possible clinical relevance of coffee consumption.<br>O café é uma substância psicoativa devido ao seu conteúdo de cafeína. A adolescência é um período desenvolvimental em que os indivíduos podem experimentar e continuar a usar substâncias psicoativas, licitas e ilícitas. Ademais, há estudos que sugerem a existência de associação entre o consumo de café e o uso de outras substâncias psicoativas. Os objetivos do estudo foram determinar os padrões de consumo de café e avaliar as associações entre o consumo de café e o de tabaco, álcool e canábis numa amostra de adolescentes portugueses. Os resultados demonstram que um elevado número de adolescentes consome frequentemente; os adolescentes apresentam preferência por café com cafeina, em comparação com o café descafeinado; e o sabor a café, o sabor das bebidas com café, e os seus efeitos psicoativos são as principais razões para consumir café na adolescência. Não foram encontradas diferenças significativas no consumo de café antes do surgimento da pandemia e durante os meses das primeiras medidas de distanciamento social. Por fim, não foram encontradas associações significativas entre o consumo de café e o consumo de outras substâncias psicoativas. A investigação futura poderá colmatar as limitações desta investigação e dedicar-se a estudar o café separadamente das outras substâncias cafeinadas.
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Bombardier, Cynthia Lee. "Prenatal exposure to cocaine and other substances: Its effect on newborn behavior and subsequent attachment behavior." 1997. https://scholarworks.umass.edu/dissertations/AAI9737507.
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The effects of prenatal substance exposure on newborn behavior and subsequent attachment quality was investigated in a sample of 29 drug-exposed infants. Participants in this study were part of a larger sample of high-risk women and their infants enrolled in a longitudinal study. Data regarding prenatal substance use, 4 weeks prior to delivery, was available for 17 infants. Prenatal substance use data were obtained from substance use histories, obstetrical and neonatal medical chart reviews and case manager notes. Frequency of substance use was reported as either $>$1 time per day, 1 time per day, 3-6 times per week, 1-2 times per week, 1-3 times per month and unknown. Qualitative substance-use data were converted to quantitative data and were correlated with newborn behavior (NBAS Lester clusters and Als dimensions). At 1 month, maternal report of prenatal substance exposure 4 weeks prior to delivery was significantly associated with the reflex cluster of the NBAS. Increased amounts of drug-exposure was related to an infant displaying an increased number of abnormal reflexes at the 1-month NBAS assessment. NBAS individual items; inanimate auditory stimuli and self-quieting were found to be positively related to attachment security, suggesting that infants with these abilities may appear more attractive to their caregivers, thus helping to create a more positive "goodness-of-fit" between infant and caregiver. Prenatal substance use throughout pregnancy (n = 13) was found to be positively associated with security of attachment (p =.03). Other factors undetected within this study (i.e. social support), may have influenced interactions between infant and caregiver and subsequently increased the potential for secure attachment. Finally, an infant's ability to attend to stimuli was found to be positively related to the attachment subcategories A1-B2 in the Strange Situation, lending further support to the idea that infant temperamental characteristics may influence whether infants are more likely to be classified as "avoidant" or "resistant", but not secure vs. insecure. Findings from this study suggest that infants exposed to drugs prenatally continue to show physiological abnormalities through the first month of life. The results were discussed in terms of implications for child development and future research.
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Gonçalves, Ricardo Daniel Teixeira. "Enantiomeric quantification of psychoactive substances and beta blockers by gas chromatography-mass spectrometry in influents of wastewater treatment plants." Master's thesis, 2018. https://hdl.handle.net/10216/117541.
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Gonçalves, Ricardo Daniel Teixeira. "Enantiomeric quantification of psychoactive substances and beta blockers by gas chromatography-mass spectrometry in influents of wastewater treatment plants." Dissertação, 2018. https://hdl.handle.net/10216/117541.
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Li, Shwu-Huey, and 李淑慧. "Comparative Biochemical Study on Zinc and Zinc Binding Substances in Tissues of Common Carp, Crucian Carp, Goldfish and Other Fishes." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/49103783291820136668.
Full textAbstract:
碩士<br>國立海洋大學<br>食品科學系<br>87<br>Abstract
Common carp (Cyprinus carpio) has extraordinarily high zinc concentrations (300-500 g/g fresh tissue) in its digestive tract tissue, the fish also has high zinc concentration (usually＞100 g/g fresh tissue) in kidney, hepatopancreas and spleen. Zinc concentration of other aquatic organisms were in the level of 20 to 100 g/g fresh tissue. In order to understand whether the phenomenon also exist in its related species, e.g., crucian carp and goldfish, biochemical properties of zinc and zinc binding substances in the tissues of common carp, crucian carp and goldfish of Cyprinae of Cyprinidae, grass carp of Leuciscinae and silver carp of Hypophthalmichthyinae of the same family, and other fishes were examined.
It was found that in Cyprinidae fishes, zinc concentrations of the digestive tract tissue of common carp, crucian carp and goldfish were about 20 times higher than those of other fishes; and kidney, spleen and hepatopancreas were about 2 times higher than those of other fishes. Zinc in subcellular fractions of tissues of common carp, crucian carp and goldfish mainly existed in the nuclei/cell debris fraction. Metallothionein-like substance were found in the cytosol of hepatopancreas of Cyprinidae fishes (crucian carp, goldfish, grass carp and silver carp), but the amount in common carp was very little. High correlation between the zinc concentrations of nuclei/cell debris fraction and total tissue of common carp, crucian carp and goldfish tissue was found. Besides, grass carp, silver carp and tilapia tissues also have the some kind of relationship. In result, zinc concentrations in the whole tissue and nuclei/cell debris fraction are related.
The Debris Fraction of fish tissues was prepared by washing nuclei/cell debris fraction with 0.05 M Tris-HCl buffer pH 8.0. High correlation between the concentration of EDTA extractable-Zn and total tissue of common carp tissue, crucian carp and goldfish digestive tract tissues was found. The concentration of Total-SH and Free-SH in the Debris Fraction of digestive tract tissues of common carp, crucian carp and goldfish were measured. High correlation between the concentration of EDTA extractable-Zn and Bound-SH in the Debris Fraction of digestive tract tissues of common carp tissue, crucian carp and goldfish was found (r=0.94); this kind of correlation, however, was not found in grass carp, silver carp and tilapia. In digestive tract tissues of spotted chub mackerel, mackerel scad, kurma prawn and giant tiger prawn, high concentration of Total-SH was found, but there is little Bound-SH. The EDTA extractable-Zn are also very low, it is likely not correlation between Bound-SH and EDTA extractable-Zn concentration.
Based on the experiments, high concentration of Zn in the digestive tract tissue seems to be a characteristics of Cyprinae fish, and the Zn might be bound in membrane protein of Debris Fraction. The Lubrol Extract of digestive tract tissues of common carp, crucian carp and goldfish were separated by IMAC. The IMAC-adsorbed proteins of digestive tract tissue of common carp, crucian carp and goldfish were compared on SDS-PAGE. It was found that crucian carp and goldfish also have ZnSBMP (zinc specific binding membrane proteins) same as common carp. Same three bands of ZnSBMP were also found in other tissues of common carp, but the concentration and composition percentage were different. In Marine fish, spotted chub mackerel, mackerel scad and scad also exist some of the bands of ZnSBMP.