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1
Callison, June. "The investigation of a side reaction leading to colour formation in a polyurethane production chain." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2498/.
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In the industrial synthesis of 4,4’-methylene diphenyl diisocyanate (MDI), an unwanted side reaction between the product and the starting material, 4,4’-methylene dianiline, can lead to the formation of ureas. It has been postulated these ureas undergo further reaction with phosgene to produce a precursor to chlorine radicals, which could then attack the MDI backbone forming conjugated systems that would promote colour in the final products. To investigate this process model compounds including 4-benzylaniline (4-BA) and 1,3-diphenylurea were used as starting materials. The reactions carried out showed the phosgenation of the urea forms a chloroformamidine-N-carbonyl chloride (CCC) which upon heating > 303 K can break down to form an isocyanide dichloride (ID). Conventional synthesis routes were used to gain high yields of p-tolyl and phenyl isocyanide dichlorides in order to analyse the compounds. It was found that upon heating to 453 K or irradiating the isocyanide dichlorides in the process solvent (chlorobenzene) coloured solutions were formed; with the presence of MDI and oxygen increasing the intensity of the colouration. Electron paramagnetic resonance spectroscopy was used to gain information on the use of isocyanide dichlorides as a source of chlorine radicals. Using N-tert-butyl--phenylnitrone (PBN) as a spin trap, an 8 line spectra relating to the chlorine adduct was measured confirming the production of Cl•. Throughout the project side reactions involving the formation of carbodiimide from CCC and a secondary route for the phosgenation of the urea to the isocyanate have been investigated and are presented within a global reaction scheme. It was also found the ureas were only partially soluble in the process solvent leading to research into the structure of three different urea molecules and the proposal of a modified reaction scheme.
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O'Brien, Michelle University of Ballarat. "A study of multiple perspectives and knowledge in adverse drug reaction decision-making : Volume 1." University of Ballarat, 2004. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/12769.
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Injury and illness associated with drugs are major problems in Australia and around the world, despite significant developments in the area of adverse drug reaction (ADR) decision support technology. The aims of this thesis are: to investigate the ADR decision domain; to determine factors that may assist in the prevention, detection and management of ADRs; and, to inform the pre-requirements analysis phase of the development of decision support systems. An approach has been taken that permits open and grounded study of the decision environment. This approach can then be used to frame and inform the design of an ADR decision support system. Fifteen case studies that comprise self selected consumers, the treating medical practitioner/s and expert perspectives of a single instance of an ADR (fifteen in-depth consumer interviews, eight in-depth medical practitioner interviews and 30 expert written questionnaires), have been collected and analysed using a grounded theory approach, a symbolic interactionist theoretical framework and a social constructionist epistemology. The analysis was performed from three perspectives: individual case study analysis (all interviews for an instance of an ADR); group analysis (consumer, medical practitioner and expert views) and analysis combining the individual case studies and groups of data. Concepts, themes and theory have emerged from these data in the following areas: • the contribution of the differences in understanding of the core concepts within this domain, to misunderstandings between decision-makers; • the consumer as a diagnostic decision-maker in the ADR decision domain; • differential diagnostic strategies used by the consumers and medical practitioners; • complexities in the ADR decision domain that make diagnosis difficult; • the role of ADR information in consumer and medical practitioner decision-making; • decision types used by consumers and medical practitioners in the ADR decision domain; • resources used by consumers, medical practitioners and experts to inform their ADR decisions; • decision-making with partial knowledge of the consumer case history, drug behaviour and diseases; • the impact of suspected ADRs on consumers and on future decision-making; • medical practitioner/consumer decision-making models; and, • reasons for low ADR reporting and the impact on the development of new ADR knowledge. The results above suggest the following: • The ADR decision domain is more complex than the current ADR decision support focus and that broadening this focus may assist in providing a more complete and useful decision support solution. • Improving the prevention, detection and management of ADRs requires more than providing prescribers with up to date ADR information. Other important factors are sharing of information, awareness of the role of the consumer, a collaborative approach between the consumers and medical practitioners, and generation of new ADR knowledge. • A grounded theory analysis of case study data using the theoretical perspectives of social constructionism and symbolic interactionism provided insight into this domain from the perspectives of multiple decision-makers. This may be an approach that can be used by systems analysts to inform the requirements analysis phases of decision support within other domains. The results of this qualitative work are preliminary. Future work is required to confirm and expand these results.Doctor of Philosophy
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O'Brien, Michelle. "A study of multiple perspectives and knowledge in adverse drug reaction decision-making : Volume 1." University of Ballarat, 2004. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/14606.
Full textAbstract:
Injury and illness associated with drugs are major problems in Australia and around the world, despite significant developments in the area of adverse drug reaction (ADR) decision support technology. The aims of this thesis are: to investigate the ADR decision domain; to determine factors that may assist in the prevention, detection and management of ADRs; and, to inform the pre-requirements analysis phase of the development of decision support systems. An approach has been taken that permits open and grounded study of the decision environment. This approach can then be used to frame and inform the design of an ADR decision support system. Fifteen case studies that comprise self selected consumers, the treating medical practitioner/s and expert perspectives of a single instance of an ADR (fifteen in-depth consumer interviews, eight in-depth medical practitioner interviews and 30 expert written questionnaires), have been collected and analysed using a grounded theory approach, a symbolic interactionist theoretical framework and a social constructionist epistemology. The analysis was performed from three perspectives: individual case study analysis (all interviews for an instance of an ADR); group analysis (consumer, medical practitioner and expert views) and analysis combining the individual case studies and groups of data. Concepts, themes and theory have emerged from these data in the following areas: • the contribution of the differences in understanding of the core concepts within this domain, to misunderstandings between decision-makers; • the consumer as a diagnostic decision-maker in the ADR decision domain; • differential diagnostic strategies used by the consumers and medical practitioners; • complexities in the ADR decision domain that make diagnosis difficult; • the role of ADR information in consumer and medical practitioner decision-making; • decision types used by consumers and medical practitioners in the ADR decision domain; • resources used by consumers, medical practitioners and experts to inform their ADR decisions; • decision-making with partial knowledge of the consumer case history, drug behaviour and diseases; • the impact of suspected ADRs on consumers and on future decision-making; • medical practitioner/consumer decision-making models; and, • reasons for low ADR reporting and the impact on the development of new ADR knowledge. The results above suggest the following: • The ADR decision domain is more complex than the current ADR decision support focus and that broadening this focus may assist in providing a more complete and useful decision support solution. • Improving the prevention, detection and management of ADRs requires more than providing prescribers with up to date ADR information. Other important factors are sharing of information, awareness of the role of the consumer, a collaborative approach between the consumers and medical practitioners, and generation of new ADR knowledge. • A grounded theory analysis of case study data using the theoretical perspectives of social constructionism and symbolic interactionism provided insight into this domain from the perspectives of multiple decision-makers. This may be an approach that can be used by systems analysts to inform the requirements analysis phases of decision support within other domains. The results of this qualitative work are preliminary. Future work is required to confirm and expand these results.Doctor of Philosophy
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Christie, Robert. "Lateral jet interaction with a supersonic crossflow." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/6815.
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A lateral jet in a supersonic crossflow creates a highly complex three-dimensional flow
field which is not easily predicted. The aim of this research was to assess the use of a
RANS based CFD method to simulate a lateral jet in supersonic crossflow interaction by
comparing the performance of available RANS turbulence models.
Four turbulence models were trialled in increasingly complex configurations; a flat
plate, a body of revolution and a body of revolution at incidence. The results of this
numerical campaign were compared to existing experimental and numerical data.
Overall the Spalart-Allmaras turbulence model provided the best fit to experimental
data. The performance of the lateral jet as a reaction control system was assed by
calculating the force and moment amplification factors. The predicted flowfield
surrounding the interaction was analysed in detail and was shown to predict the
accepted shock and vortical structures. The lateral jet interaction flowfield over a body
of revolution was shown to be qualitatively the same as that over a flat plate.
An experimental facility was designed and manufactured allowing the study of the
lateral jet interaction in Cranfield University’s 2 ½” x 2 ½” supersonic windtunnel. The
interaction was studied with a freestream Mach number of 1.8, 2.4 & 3.1 and over a
range of pressure ratios (50≤PR≤200). Levels of unsteadiness in the interaction were
measured using high bandwidth pressure transducers. The level of unsteadiness was
quantified by calculating the OASPL of the pressure signal. OASPL was found to
increase with increasing levels of PR or MPR and to decrease with increases of Mach
number. The levels of unsteadiness found were low with the highest levels found
downstream of the jet.
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Petrov, Ravil Rashitovich. "Part I. Application of 2-Hydroxymethylacrylic Acid, a Product of Baylis-Hillman Reaction, for the Synthesis of Novel N-backbone-to-Side-Chain Cyclic Peptide Analogs: Strategies and Side Reactions Part II. Synthesis and Biological Activities of Chimeric Bioactive Peptides Featuring Amino Acids Coupled to 4-Anilino-N-Phenethyl-Piperidine." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194330.
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During my research career in Prof. V.J.Hruby's laboratory I worked on two different projects. The first project, which was initiated by the author, was planned to serve the need of our laboratory for a novel method of peptide cyclization. This method was planned to use recent advances in Pd0-catalyzed asymmetric synthesis combined with the structural richness offered by the Baylis-Hillman chemistry which could open new ways to diverse areas of drug design, molecular immunology and chemotherapy. This approach would provide cyclic peptides featuring N-alkylated amino acids that would confer high resistance to degradation by proteases. Because of numerous synthetic problems imposed, this strategy was not of considerable current use in peptide synthesis, especially on solid supports. However, despite a substantial amount of effort invested, this method faced serious drawbacks such as multistep synthesis and side reactions when applied to solid supports. Moreover, recent introduction of microwave technology which has helped to solve a great number of problems has led to a renaissance in the classical lactam and thioester bond cyclizations which overshadowed our quest for a novel methodology. The second project was focused on application of 4-anilidopiperidines for the synthesis of chimeric bioactive peptides. It was an effort towards the development of novel analgesics with reduced toxicity and enhanced potency. This project linked small molecule and multimeric ligand designs that were ongoing in our laboratory at the time. Major accomplishments in this project were made possible by successful resolution of several research challenges. I was able to find a straightforward, convenient and economical approach for the synthesis of novel analogues on a solid support. These developments led to novel compounds which showed substantial increases in their binding affinity relative to corresponding opioid analogues. To illustrate, compounds PET25, 26, 27, 29, 30, 31, and 32 showed high bioactivity and sub-nanomolar binding affinity to opioid receptors. Most of the peptides generated in the second project are still being investigated for their biological activities by our colleagues at the Department of Pharmacology, but the results to date indicate that some highly potent novel compounds have been made.
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Gouws, Stephanus Andries. "The impact of hospital surveillance programmes on the incidence of adverse drug reaction reporting in a South African teaching hospital." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/27186.
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Post-marketing surveillance refers to any non-experimental or observational study, method, or monitoring strategy that is applied to obtain information on drug experience (primarily adverse) after a drug has been approved for clinical use. One of the major problems in post-marketing surveillance studies is the lack or under-reporting of drug experiences by health care professionals. This study was developed to describe the impact of three different prescription event monitoring programmes on the reporting of adverse drug reactions (ADR's) in the hospital situation. The intensive ADR monitoring programme and two voluntary ADR monitoring programmes which followed were conducted in the medical wards of an urban teaching and referral hospital. All patients admitted to the designated wards were monitored by a dedicated pharmacist in the intensive programme, ward pharmacists in the first voluntary programme and by medical and nursing staff in the second voluntary programme. The pharmacist monitored a cohort of patients prospectively in two medical wards for a period of three months. The patient's record was linked with any suspected ADR. All details, i.e. patient drug orders, characteristics and ADR description, were recorded and then reported. From 228 patients monitored, 25 cases have been reported. The impact of the intensive ADR monitoring programme was a reporting rate of 11 percent. Reports were received on ADR's of a particularly mild, common and pharmacologically predictable (type A) nature. The first voluntary ADR monitoring programme comprised the reporting of suspected AD R's and the recording of drug orders for the patients and the patient characteristics. The ward pharmacists monitored for suspected AD R's in all patients during their regular ward rounds. Six cases were reported in a population of 1506 patients monitored during the three months. The reports were mainly on moderate to severe suspected AD R's of pharmacologically unpredictable (type B) nature. The rate of reports received by the surveillance unit in this study was 4 reports per ward pharmacist per annum. The second voluntary ADR monitoring programme comprised the prospective monitoring of 1555 patients by medical and nursing staff during their stay at the designated medical wards during the three month period. Patients were monitored for any ADR and when an ADR was suspected, the patient characteristics and drug orders were recorded and reported to the surveillance unit. Ten cases were reported represented by six reports from doctors and four by sisters. The reporting rate was 2 reports per doctor in four years and 3 reports for each member of the nursing team in 5 years. Reports were mainly received on moderate to severe suspected ADR's of a pharmacologically unpredictable (type B) nature.
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Rudatsikira, Alphonse. "Contribution a l'etude du dopage n du polyacetylene." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13188.
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Hilbers, Florian [Verfasser], Bernd [Akademischer Betreuer] Ludwig, and Hartmut [Akademischer Betreuer] Michel. "Comparison of the cytochrome c oxidase inherent catalase side-reaction from Paracoccus denitrificans in the wild type and recombinant form / Florian Hilbers. Gutachter: Bernd Ludwig ; Hartmut Michel." Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2015. http://d-nb.info/1077607717/34.
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Mota, Daniel Marques. "Evolução e resultados do sistema de farmacovigilância do brasil." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/159285.
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Os sistemas de farmacovigilância fundamentam as decisões sobre segurança no uso de medicamentos regulamentados por autoridades de saúde. Estudá-los e propor estratégias de melhorias contribuem para fortalecer os sistemas de saúde, aperfeiçoando a qualidade da assistência à saúde e assegurando a segurança do paciente e coletividade. A Tese objetivou analisar a evolução e desempenho do sistema brasileiro de farmacovigilância, denominado de SINAF, e as notificações dos pacientes com suspeitas de reações adversas a medicamentos (RAMs) registradas no Notivisa-medicamento no período de 2008 a 2013 e propor uma lista-referência de códigos da CID-10 para vigilância de RAMs e intoxicações medicamentosas (IMs). A Tese compreende seis artigos científicos organizados para publicação. No primeiro, uma revisão de escopo apresentou uma perspectiva histórica para caracterizar a evolução do SINAF e lacunas identificadas no processo, como a ausência de comissão de farmacovigilância que atenda aos requisitos mínimos de um sistema de farmacovigilância propostos pela Organização Mundial da Saúde. Os artigos 2, 3 e 4 analisaram características relacionadas com o desempenho do SINAF. O artigo 2 revelou que não há preferência digital da idade na base de dados das notificações de eventos adversos a medicamentos (EAMs) do Notivisa-medicamento. Mediante uma análise comparativa, o artigo 3 mostrou diferenças entre o formulário para notificação de EAMs utilizado no SINAF e de outros doze países latinoamericanos (Argentina, Bolívia, Chile, Colômbia, Costa Rica, Cuba, Guatemala, México, Panamá, Peru, Uruguai e Venezuela), sobretudo na quantidade de variáveis para preenchimento, podendo contribuir com a subnotificação de casos. No artigo 4 – um estudo de avaliação de sistemas de vigilância de saúde pública –, revelou que o desempenho do Notivisa-medicamento foi considerado satisfatório para três atributos (flexibilidade, validade e erro preditivo positivo) e deficitário para a maioria deles (simplicidade, aceitabilidade, representatividade, completude, consistência, oportunidade e clareza metodológica). O artigo 5, mediante estudo descritivo e retrospectivo, encontrou uma taxa de notificação de RAMs de 22,8/ 1 milhão de habitantes/ano. Trata-se de taxa bastante inferior a países de alta renda como Nova Zelândia, Suécia, Austrália e Suíça que possuem mais de 300 notificações por milhão, como em relação a países de média renda, como a África do Sul, com taxa de 77 por milhão de habitantes. A população feminina (60,5%) prevaleceu no total de pacientes (26.554), assim como, a raça/cor branca (58,1%). A idade variou de 0 a 112 anos (mediana = 46 anos). Quase 1/3 (32,5%) das suspeitas de RAMs ocorreram em populações vulneráveis (idosos e crianças). Foram avaliados 54.288 pares de medicamento-reação adversa, onde prevaleceram as reações adversas graves (59,2%), com destaque para as que resultaram em efeito clinicamente importante (83,1%). O estudo 6 propôs uma lista-referência com 691 códigos da CID-10, sendo 360 (52,1%) relacionados com RAMs e 331 (47,9%) com IMs. Um total de 511 (73,9%) códigos estão relacionados com casos de admissão hospitalar e/ou óbito. Os achados da Tese evidenciam a necessidade de mudanças em diferentes aspectos estudados do SINAF, como forma de contribuir na produção de informações completas, fidedignas e mais representativas sobre danos ocasionados por medicamentos comercializados no país.The pharmacovigilance systems support the decisions on safety when using medications regulated by health authorities. Analyzing them and proposing improvement strategies are ways to make healthcare systems stronger, improving the quality of healthcare assistance, making sure the patient is safe and that the population is ensured. The dissertation was aimed at analyzing the evolution and performance of the Brazilian pharmacovigilance system, SINAF, and the notification of patients with suspected adverse drug reactions (ADRs) registered with the notification system NOTIVISA/medication from 2008 through 2013, as well as proposing a reference list of ICD-10 codes for surveillance of ADRs and intoxication due to medication (IDM). The dissertation is comprised of six scientific articles ready to be published. The first one, a scoping review, presents a historical perspective to demonstrate the development process of SINAF and the gaps identified during the process, such as the absence of a pharmacovigilance commission that complies with the minimum requirements of a pharmacovigilance system as proposed by World Health Organization. Articles 2, 3 and 4 presents an analysis of the performance-related characteristics of SINAF. Article 2 reveals that there is no digital age preference in the adverse drug events (ADEs) database belonging to NOTIVISA/medication. Using a comparative analysis, article 3 shows differences between the form for ADEs notification using SINAF and in other twelve Latin-American countries (Bolivia, Chile, Colombia, Costa Rica, Cuba, Guatemala, Mexico, Panama, Peru, Uruguay and Venezuela), highlighting the number of variables to complete, and it may collaborate with the sub-notification of cases. Article 4 – a study on the evaluation of public health surveillance systems over time – reveal that the performance of NOTIVISA/medication was considered satisfactory regarding three attributes (flexibility, validity and positive predictive error) and deficient regarding most of the others (simplicity, acceptability, representability, integrality, consistency, opportunity and methodological clarity). Article 5, by means of a descriptive and retrospective study, found an ADR notification rate of 22.8/million inhabitants/year. This is a much lower rate than in high income countries, such as New Zealand, Sweden, Australia and Switzerland, which have over 300 notifications per million, when compared against average income, such as South Africa, with a rate of 77/million inhabitants. Female population (60.5%) prevailed in the total number of patients (26,554), as well as white race/color (58.1%). Age was between 0 - 112 years old (median = 46 years). Almost 1/3 (32.5%) of the suspected ADRs occurred in vulnerable populations (elderly and children). 54,288 pairs of medication/adverse reactions were assessed. Severe adverse reactions prevailed (59.2%), and attention is drawn to those resulting in clinically important effect (83.1%). Study 6 proposes a reference list with 691 ICD-10 codes; 360 (52.1%) out of them are ADRs-related and 331 (47.9%) out of them are IDM. A total of 511 (73.9%) codes are related to cases of hospital admission and/or death. The dissertation findings prove the need of changes across different aspects in SINAF as a way to contribute to production of complete, reliable and representative information on damages caused by commercially available drugs in Brazil.
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Pierfederici, Andrea. "Eventi avversi nelle manipolazioni cervicali: revisione della letteratura." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Find full textAbstract:
Introduzione: La manipolazione spinale cervicale è una tecnica di terapia manuale utilizzata per trattare problematiche muscoloscheletriche. Se da un lato ci sono evidenze che supportano l’efficacia terapeutica della tecnica, dall’altro ci sono dubbi per quanto riguarda la sicurezza del trattamento.
Obiettivo: Valutare attraverso le evidenze scientifiche presenti in letteratura tutti gli eventi avversi, e la loro incidenza, correlati alla manipolazione del tratto cervicale nella popolazione adulta.
Metodi: La ricerca per l'individuazione dei contributi scientifici è stata avviata, da febbraio a settembre del 2020, su tre database scientifici: PubMed, PEDro e Cochrane Library. Sono stati selezionati inizialmente solamente studi clinici randomizzati, e successivamente a causa dell’assenza di eventi avversi moderati/gravi, si è deciso di includere anche studi osservazionali. La qualità metodologica degli studi è stata stabilita attraverso la scala PEDro, per studi clinici randomizzati, e la Newcastle-Ottawa Scale, per studi osservazionali.
Risultati: Sono risultati eleggibili quattro studi clinici randomizzati e due studi osservazionali. Dall’analisi degli articoli presi in considerazione emerge che se gli eventi avversi minori in seguito alla manipolazione cervicale sono relativamente comuni, invece il rischio di un evento moderato/grave è estremamente basso. Dagli studi osservazionali inclusi non emerge una correlazione significativa tra manipolazione cervicale e l’ictus vertebro-basilare, a differenza di altri presenti in letteratura.
Conclusioni: Considerando la natura transitoria degli effetti collaterali minori e l’estrema rarità degli eventi avversi moderati/gravi, possiamo considerare la manipolazione spinale cervicale come un’opzione terapeutica con un rapporto beneficio-rischio “bilanciato”. Ulteriori studi sono necessari per potere raggiungere una maggiore consapevolezza sull’argomento degli eventi avversi più gravi.
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Soutif, Jean-Claude. "Etude de l'addition des acides carboxyliques sur les structures oxiranne : application aux polymeres epoxydes." Le Mans, 1987. http://www.theses.fr/1987LEMA1010.
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La modification chimique au deuxieme degre de polymeres epoxydes a ete etudiee pour developper une methode de fixation de principes actifs (medicaments, colorants, complexants) comportant des fonctions acides, sur des supports macromoleculaires. Le catalyseur est un sel de tetramethylammonium de l'acide a fixer. Epoxydation de polyisoprene et polybutadiene
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Bellón, Molina Víctor. "Prédiction personalisée des effets secondaires indésirables de médicaments." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM023/document.
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Les effets indésirables médicamenteux (EIM) ont des répercussions considérables tant sur la santé que sur l'économie. De 1,9% à 2,3% des patients hospitalisés en sont victimes, et leur coût a récemment été estimé aux alentours de 400 millions d'euros pour la seule Allemagne. De plus, les EIM sont fréquemment la cause du retrait d'un médicament du marché, conduisant à des pertes pour l'industrie pharmaceutique se chiffrant parfois en millions d'euros.De multiples études suggèrent que des facteurs génétiques jouent un rôle non négligeable dans la réponse des patients à leur traitement. Cette réponse comprend non seulement les effets thérapeutiques attendus, mais aussi les effets secondaires potentiels. C'est un phénomène complexe, et nous nous tournons vers l'apprentissage statistique pour proposer de nouveaux outils permettant de mieux le comprendre.Nous étudions différents problèmes liés à la prédiction de la réponse d'un patient à son traitement à partir de son profil génétique. Pour ce faire, nous nous plaçons dans le cadre de l'apprentissage statistique multitâche, qui consiste à combiner les données disponibles pour plusieurs problèmes liés afin de les résoudre simultanément.Nous proposons un nouveau modèle linéaire de prédiction multitâche qui s'appuie sur des descripteurs des tâches pour sélectionner les variables pertinentes et améliorer les prédictions obtenues par les algorithmes de l'état de l'art. Enfin, nous étudions comment améliorer la stabilité des variables sélectionnées, afin d'obtenir des modèles interprétablesAdverse drug reaction (ADR) is a serious concern that has important health and economical repercussions. Between 1.9%-2.3% of the hospitalized patients suffer from ADR, and the annual cost of ADR have been estimated to be of 400 million euros in Germany alone. Furthermore, ADRs can cause the withdrawal of a drug from the market, which can cause up to millions of dollars of losses to the pharmaceutical industry.Multiple studies suggest that genetic factors may play a role in the response of the patients to their treatment. This covers not only the response in terms of the intended main effect, but also % according toin terms of potential side effects. The complexity of predicting drug response suggests that machine learning could bring new tools and techniques for understanding ADR.In this doctoral thesis, we study different problems related to drug response prediction, based on the genetic characteristics of patients.We frame them through multitask machine learning frameworks, which combine all data available for related problems in order to solve them at the same time.We propose a novel model for multitask linear prediction that uses task descriptors to select relevant features and make predictions with better performance as state-of-the-art algorithms. Finally, we study strategies for increasing the stability of the selected features, in order to improve interpretability for biological applications
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Kapadi, Ajith Nayak. "Size Exclusion PEGylation Reaction Chromatography Modelling." The University of Waikato, 2006. http://hdl.handle.net/10289/2504.
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Size exclusion PEGylation reaction chromatography was investigated using a model developed by Fee (2005). Column dispersion was neglected and the PEGylation reaction was modelled as second order. The model allowed up to four PEG groups to be attached to a protein and accounted for succinic acid hydrolysis from activated PEG. The model was adapted to simulate a-lactalbumin PEGylation and succinic acid hydrolysis from activated PEG in a batch stirred tank so rate parameters from stirred tank kinetic experiments could be obtained and the model verified. The model was solved using finite differences and simulations run in Matlab. The effect of reaction parameters such as timing, length and concentration of PEG and protein injection, reaction rates, and model resolution on model simulation results was explored. In the size exclusion PEGylation simulations it was found that increasing protein concentration increased MonoPEG concentrations and increased the ratio of MonoPEG to starting protein feed concentration. Increasing PEG pulse length and starting PEG concentration initially increased MonoPEG concentration and product ratio until all protein had been PEGylated at which point MonoPEG concentration the product ratio levelled out. Increasing PEG hydrolysis rates did not affect the amount of MonoPEG produced but reduced the activated PEG concentration and increased succinic acid concentration. Optimal conditions for producing MonoPEG were found to be equal concentrations of PEG and protein, with the PEG injection length twice as long as the protein injection, and the PEG injection done immediately after the protein injection.
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Lau, Phyllis Min-yu. "Adverse drug reactions in oncology." Monash University, Dept. of Pharmacy Practice, 2003. http://arrow.monash.edu.au/hdl/1959.1/5549.
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Jenzer, Herbert Kurt. "Molecular mechanisms and side reactions of thyroid hormone biosynthesis /." [S.l : s.n.], 1987. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Dong, Yi. "Single site surface reactions : STM Studies." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/30204.
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La demande des composants chimiques énantiopurs dans le secteur pharmaceutique est une des forces qui motive la recherche dans la création des catalyseurs homochiraux à la surface. La catalyse hétérogène est une méthode prometteuse pour la fabrication des produits énantiopurs puisqu'elle porte des avantages tels que la facilité de la séparation des produits désirés, la réutilisation du catalyseur et l'adaptabilité dans différentes conditions de la production en continu. La réaction d'Orito est un des exemples de la réaction hétérogène énantiosélective la plus réussie. Elle concerne l'hydrogénation de α-cétoesters sur des particules de platine modifiées par le cinchona. Il est généralement accepté que des modificateurs cinchona tels que la cinchonidine ou la cinchonine transfère la chiralité en formant des complexes bimoléculaires (complexes 1 :1) avec des réactifs prochiraux sur la surface. La compréhension de la catalyse asymétrique hétérogène au niveau fondamental est insu sante. Par contre, c'est aussi une zone fertile pour la découverte. Du progrès dans le domaine peut être réalisé par des travaux complémentaires en catalyse, en sciences des surfaces et en calcul théorique. Cette thèse décrit les études en science des surfaces inspirées par des rapports dans la littérature sur la réaction d'Orito. En plus des alcaloïdes du cinchona, qui sont des produits naturels, certains nombres de molécules synthétiques sont également des modificateurs chiraux pour la réaction d'Orito. En particulier, Baiker et ses collègues ont enquêté sur la performance du 1-(1-naphtyl)éthylamine (NEA) optiquement pur en tant que modificateur chiral pour l'hydrogénation énantiosélective de cétopantolactone (KPL) en pantolactone sur le Pt/Al2O3.1 Une partie du travail décrit dans cette thèse est l'étude des complexes formés par l'interaction de (R)-NEA et KPL sur la surface de monocristal Pt(111). Le microscope à e et tunnel (STM) est utilisé pour acquérir un grand nombre d'images des complexes KPL/(R)-NEA. Les mesures sont effectuées sur un large rapport de couverture de KPL à (R)-NEA sur la surface. Un algorithme est développé pour accélérer le comptage et la catégorisation de la forme du grand ensemble d'images STM des complexes. L'abondance de plusieurs complexes distincts qui impliquent toute une liaison hydrogène NH···O est déterminée. La prochiralité de KPL dans ces complexes sont attribuées en référant des images STM simulées par théorie de la fonctionnelle de la densité (DFT). Le rapport prochiral global (pr) mesuré dans l'expérience de la surface est comparé au rapport énantiomérique (er) mesuré par Baiker et ses collègues. Un autre algorithme est développé pour l'analyse des événements dynamiques des complexes diastéréomères individuels. Il est appliqué pour tester l'interconversion d'un état à l'autre état pendant la durée de vie de chaque complexe qui est observée par STM. Les résultats sont présentés pour les complexes formés entre 2,2,2-trifluoroacetophenone (TFAP) et (R)-NEA sur le Pt(111). Les complexes TFAP/(R)-NEA montrent des événements dynamiques qui sont décrits comme décomplexation, inversion prochirale sur site et migration intracomplexe. Les résultats sont discutés en référant les barrières énergétiques prédites par DFT pour l'hydrogénation et pour l'inversion prochirale sur site. Un rapport préliminaire présente les données quantitatives sur les interconversions des états aux états des complexes individuels des trois systèmes : TFAP/(R)-NEA, KPL/(R)-NEA et TFAP/8-Me-(R)-NEA. Le dernier modificateur de la surface concerne la substitution d'un méthyle à l'hydrogène à la position 8 du groupe naphtyle du (R)-NEA. Les observations sur les complexes KPL/(R)-NEA et TFAP/(R)-NEA sont résumés dans le contexte des données de science de surface précédemment publiées de notre groupe. La revue met l'accent sur le rôle des interactions secondaires, CH···O et CF···H, dans le contrôle stéréoscopique des molécules prochirales.The demand for enantiopure compounds in the pharmacological sectorsisastrong driving force for research aimed at creating homochiral catalyst surfaces. Heterogeneous catalysts offer potential advantages over homogeneous catalysts including ease of separation of products from the catalyst and greater suitability for operations under continuous ow conditions. One of the most successful examples of a heterogeneous enantioselective reaction is known as the Orito reaction, the hydrogenation of α-ketoesters on cinchona modi ed platinum particles. It is believed that the cinchona modi ers operate chirality transfer by forming bimolecular surface complexes with prochiral reactants. At a fundamental level, heterogeneous asymmetric catalysis is a poorly understood area of surface chemistry. Hence, it is also a fertile area for discovery. Progress in the area can best be made by complementary work in catalysis, surface science and computation. This thesis describes surface science studies that were inspired by reports in the catalysis literature on the Orito reaction. In addition to cinchona alkaloids, which are natural products, a number of synthetic molecules have been shown to be effective chiral modifiers for the Orito reaction. In particular, Baiker and co-workers explored the performance of optically pure 1-(1-naphtyl)-ethylamine (NEA) as a chiral modifier for the enantioselective hydrogenation of ketopantolactone (KPL) to pantolactone on Pt/Al2O3.1 A major part of the work described in this thesis deals with the investigation of surface complexes formed through the interaction of (R)-NEA and KPL on single crystal Pt(111). Scanning tunnelling microscopy (STM) measurements were used to acquire a large number of images of KPL/(R)-NEA complexes. The measurements were performed over a wide ratio KPL to (R)-NEA surface coverage ratios. An algorithm was developed to enable accelerated counting and cataloguing of the large set of STM images of complexes. Therelativeabundancesofmultipledistinctcomplexationstates, allinvolvingNH·· ·O hydrogen bonding, were determined. The prochirality of KPL in these states was assigned by reference to density functional theory (DFT) simulated STM images. The overall prochiral ratio (pr) measured in the surface science experiment was compared to the enantiomeric ratio (er) measured by Baiker and co-workers. An algorithm was developed to investigate uxional events in individual diastereomeric complexes. It was applied to examine state-to-state interconversion occurring during the life times of complexes, as observed using time-lapsed STM measurements. Results are presented for complexes formed by 2,2,2-trifluoroacetophenone (TFAP) interacting with (R)-NEA on Pt(111). The TFAP/(R)-NEA complexes show dynamic events that we describe as decomplexation, on-site prochiral inversion and intracomplex migration. The results are discussed in relation to energy barriers predicted by DFT for hydrogenation and for on-site prochiral inversion. Quantitative data for state-to-state interconversion in single complexes are presented for three systems: TFAP/(R)-NEA, KPL/(R)-NEA and for TFAP interacting with methyl-substituted (R)-NEA. A preliminary analysis of the data is presented. The observations on KPL/(R)-NEA and TFAP/(R)-NEA complexes are reviewed within the context of previously published surface science data from our group. The review emphasizes the role of secondary interactions, CH···O and CF···H bonding, in the stereocontrol of prochiral molecules.
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Heslop, Stacy L., Lauren Peckler, and Anthony J. Muscat. "Reaction of aqueous ammonium sulfide on SiGe 25%." A V S AMER INST PHYSICS, 2017. http://hdl.handle.net/10150/624395.
Full textAbstract:
SiGe 25% substrates were treated with aqueous solutions of ammonium sulfide with and without added acid to understand the adsorption of sulfur on the surface. X-ray photoelectron spectroscopy showed no sulfide layer was deposited from aqueous (NH4)(2)S alone and instead both Si and Ge oxides formed during immersion in the sulfur solution. The addition of hydrofluoric and hydrochloric acids dropped the pH from 10 to 8 and deposited sulfides, yet increased the oxide coverage on the surface and preferentially formed Ge oxides. The sulfur coverage grew with increasing concentrations of acid in the aqueous (NH4)(2)S. The simultaneous deposition of O and S is suspected to be the result of oxidized sulfur species in solution. Metal-insulator-semiconductor capacitor (MISCAP) devices were fabricated to test the electrical consequences of aqueous ammonium sulfide wet chemistries on SiGe. MISCAPs treated with acidic ammonium sulfide solutions contained fewer interface defects in the valence band region. The defect density (D-it) was on the order of 10(+12) cm(-2) eV(-1). The flat band voltage shift was lower after the acidic ammonium sulfide treatment, despite the presence of surface oxides. Adsorption of S and potentially O improved the stability of the surface and made it less electrically active. (C) 2017 American Vacuum Society.
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Wahyu, Haifa. "The identification of side reactions and by-products in process synthesis." Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/13165.
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This work presents a systematic approach to the identification of possible by-products in process synthesis. The objective is to discover all possible reactions that might take place in a reaction system, in addition to already known main reactions. These side reactions may generate species in minor quantities which can be difficult to separate and therefore be into the recycle system. These species can thus remain in the process and accumulate. A literature survey indicated that generic languages for chemical reactions have been developed recently by other workers. These have adopted the concepts of fundamental chemistry with the aim of identifying major chemical reactions. For the purpose of the present work, strict interpretation of chemistry was not considered necessary since the aim was to generate minor species which might be formed. The work covers aspects of molecular representation, reaction generation and thermodynamic evaluation for screening. Molecular properties are estimated using group contribution methods. Unlikely species are ruled out using both stoichiometric and thermodynamic tests. The approach was first tested by comparison with experimental work, on the partial wet oxidation of p-coumaric acid and alkylation of toluene with ethanol. This shows favourable results. Process case studies were then undertaken including vinyl chloride monomer and the preparation of R-134a and R-22. These processes have been used to study the effect of by-product build-up. The study involved separation simulation to investigate the separability of the components. This confirmed that many potential by-products would be difficult to separate and might tend to accumulate in recycles. The results show that the approach has a promise for identifying possible side reactions, by-products and the problems that they will cause in a continuous process. Thus in the long term the approach affects the possibility of reducing and eliminating pilot plant studies in moving from laboratories to full scale processes.
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Wu, Zimei, and n/a. "Formulation approaches to minimise injection site reactions of poorly soluble drugs." University of Otago. School of Pharmacy, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070503.122315.
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Purpose: The aim of this study was to investigate the usefulness of formulation approaches to minimise injection site reactions for poorly soluble drugs. The specific objectives were to modify the injection site reactions by identification of irritant components in the formulation and control of their release kinetics; and to gain understanding of formulation approaches to create a favourable microenvironment in the tissues allowing better tissue tolerance and drug absorption.
Methods: Physicochemical properties of the model drug, ricobendazole (RBZ) were characterised using conventional methods. Three formulation approaches to minimise irritancy of the low pH RBZ solution were assessed. An in vitro method using 96-well microplates and a microtiter plate reader was used for detection of drug precipitation on dilution for formulation characterisation. Cellular damage by the formulations was investigated in L929 fibroblasts using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy phenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and lactate dehydrogenase (LDH) assays. Tissue tolerance and pharmacokinetics were simultaneously investigated after subcutaneous injection in sheep. A low pH RBZ solution was used as a reference formulation.
Results: Preformulation studies showed that RBZ was practically insoluble in water and oils, and was slightly soluble in commonly used co-solvents. Solubility was slightly improved by complexation with hydroxypropyl-β-cyclodextrin (HP-β-CD, K₁:₁ = 311 M⁻�) or a combination of low pH (> 2) with surfactants or co-solvents. A U-shaped pH-solubility profile in aqueous solutions indicated that RBZ is an ampholyte. pKa values measured by absorbance spectroscopy and pH solubility methods were 3.45 and 3.76 (basic) and 9.82 and 9.53 (acidic) respectively. The partition coefficient was 14.3 - 15.2 at pH 6 - 9 and less at higher or lower pH. In aqueous solutions, RBZ showed a V-shaped pH-degradation rate profile and was most stable at pH 4.8. Degradation pathways were identified as hydrolysis and oxidation.
Three RBZ injectables (5%) were obtained by modification of the low pH RBZ solution; addition of 20% HP-β-CD, incorporation into a w/o emulsion, and a microemulsion (ME). On dilution with SPB, the onset time of drug precipitation was prolonged and the rate was reduced in the presence of HP-β-CD. The w/o emulsion had a low viscosity (< 60 mPa.s) and exhibited Newtonian flow. Drug release versus the square root of time was linear and the release rate could be adjusted by phase ratio and droplet size. Drug release was found to be by diffusion. A coarse emulsion layer appeared at the interface between the ME and buffer. Drug release from the ME was faster than from the emulsion and was linear with the square root of time. On titration into SPB, the three formulations showed controlling effects on the release of H₃O⁺ compared to the reference formulation. RBZ (0.1 mg/ml) was more toxic to L929 cells than the co-solvent propylene glycol (50 mg/ml). The formulations showed greater cytotoxicity than their vehicles in the order: ME > RBZ solution = emulsion > HP-β-CD. HP-β-CD and emulsion excipients showed little or no cytotoxicity. The MEs exhibited more toxicity in the LDH assay than in the MTS assay.
A reversed phase HPLC assay for simultaneous determination of RBZ and its metabolite in sheep plasma using an isocratic system with UV detection was developed and used in the pharmacokinetic studies. Plasma samples were prepared by solid phase extraction. A suitable internal standard was selected by quantitative structure-retention relationships analysis. The composition of a ternary mobile phase was optimised with the assistance of multiple linear regression. The assays were linear over the concentration range 10 - 1000 ng/ml for both analytes (r > 0.999) with satisfactory inter-day and intra-day precision and accuracy (CV < 10%). The recoveries for all analytes were > 96%.
A pilot study in sheep suggests that injection of the vehicles (the CD, emulsion and ME) caused virtually no pain on injection or site reactions. Both the reference formulation and its vehicle induced pain on injection and resulted in swollen tissues. Histology after two weeks showed granulation for the formulation, but not the vehicle. In contrast, animals showed virtually no injection site reactions with the ME and emulsion. The HP-β-CD formulation gave transient pain on injection but a two-fold increase in bioavailability compared with the reference. The emulsion produced sustained drug release and increased drug absorption. In the main study, the HP-β-CD vehicle showed good tissue compatibility. Irritation by the HP-β-CD formulation was attributed to the low pH. Cmax, tmax and AUC0-[infinity] for the reference formulation were 1.3 � 0.3 [mu]g/ml, 9.6 � 2.9 h and 36.7 � 9.2 [mu]g�h/ml respectively, while the corresponding data for the HP-β-CD formulation were 2.9 � 0.8 [mu]g/ml, 5.0 � 0.6 h and 54.5 � 15.3 [mu]g�h/ml respectively. The half-life following the injection of the HP-β-CD formulation (5.5 � 2.8 h) was shorter than that of the reference formulation (8.5 � 3.4 h).
Conclusions: Injection site reactions may be minimised by identification of irritant components in a formulation and by controlling their release. Controlling the burst release of the poorly water soluble drug RBZ in a low pH solution could improve tissue tolerance and minimise post-injection precipitation, and hence increase drug bioavailability. In addition, HP-β-CD was a useful local injectable carrier which significantly enhanced the absorption of RBZ after subcutaneous injection in sheep.
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Govindarajulu, Sree Sharanya. "Reaction mechanism for packet size-based misbehavior in wireless networks." Thesis, Wichita State University, 2011. http://hdl.handle.net/10057/3954.
Full textAbstract:
Since the field of wireless technology is growing rapidly, security is becoming a major
concern. A variety of security problems are being addressed, and much research work is taking
place in order to provide adequate security to prevent hackers from disrupting network service.
Wireless networks follow the IEEE 802.11 standard to transmit and receive packets. The IEEE
802.11 MAC protocol is designed in such a way to provide an equal share of throughput among
all nodes in a network. Users who misbehave could modify the IEEE 802.11 MAC protocol, thus
causing major security threats including substantial bandwidth degradation of other users.
This thesis addresses the misbehavior of a node caused by altering the packet size. For a
node to acquire higher throughput compared to other genuine nodes in the network, its packet
size could be set higher than that of the genuine nodes. In order to protect against this sort of
misbehavior, a special algorithm, which is a slight modification of the IEEE 802.11 MAC
protocol, was developed.
This algorithm is based on the notion of receiver-assigned backoff, which has already
been used to deal with other types of misbehavior. The packet size-based misbehavior was
modeled mathematically using queuing theory, and an appropriate reaction strategy was deduced
from the analytical results. It was shown that the proposed approach reduces the effectiveness of
misbehavior and leads to fairness in the network.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.
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臼井, 明日香. "ラジカル超原子価ヨウ素(III)試薬を用いた直接的C-H活性化反応の開発." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199117.
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Tetreault, Michelle Lynn. "Investigation of the docking and electron transfer reactions between cytochrome c₂ and the reaction center from the photosynthetic bacteria Rhodobacter sphaeroides using site-directed mutants /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9945781.
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Hanover, Karl Frederic. "The hydrogenation of glucose with Raney-nickel : an examination of the side reactions /." Thesis, Connect to this title online; UW restricted, 1987. http://hdl.handle.net/1773/5514.
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Motter, Fabiane Raquel. "Desenvolvimento de critérios explícitos adaptados à realidade brasileira para avaliação do uso de medicamentos potencialmente inapropriados para idosos." Universidade do Vale do Rio dos Sinos, 2018. http://www.repositorio.jesuita.org.br/handle/UNISINOS/7150.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
UNISINOS - Universidade do Vale do Rio dos Sinos
O uso de Medicamentos Potencialmente Inapropriados (MPIs) em idosos pode comprometer a efetividade ou a segurança da farmacoterapia e têm se destacado como importante desafio para saúde pública, visto que está associado a elevados índices de morbidade e mortalidade. Pesquisas nacionais que investigaram esse tema revelam que as prevalências de uso de MPIs variam de 28,0% a 82,6%; contudo, esses estudos utilizaram listas de MPIs validadas na América do Norte e Europa, uma vez que o primeiro consenso brasileiro sobre MPIs foi publicado somente no final de 2016. Segundo os autores, a lista desenvolvida apresenta algumas lacunas no conhecimento, uma vez que foi baseada em critérios publicados até 2012 e, portanto, não inclui as versões mais atualizadas publicadas em 2015, bem como não incorpora possíveis alternativas terapêuticas para os medicamentos que compõem a lista. Dessa forma, este estudo teve como objetivo estabelecer critérios explícitos para avaliação de MPIs prescritos aos idosos no Brasil e suas respetivas alternativas terapêuticas. O projeto englobou duas etapas complementares: 1- Elaboração da lista de critérios explícitos para avaliação de medicamentos inapropriados para idosos a partir de revisão sistemática já realizada; 2- Validação da proposta por consenso de especialistas utilizando técnica Delphi; A primeira etapa, elaboração da lista preliminar de MPIs, foi baseada em um estudo de revisão sistemática das listas publicadas entre janeiro/1991 e abril/2017.Realizou-se também uma análise qualitativa das listas com o objetivo de verificar a aplicabilidade destas ao mercado brasileiro em termos de disponibilidade e frequência de prescrição. Dessa forma, selecionaram-se três listas de MPIs: Beers 2015, STOPP 2015, European Union (7) PIM list. Ao final desse processo, obteve-se 153 critérios distribuídos em sete instrumentos: Dor e Inflamação, Sistema Cardiovascular, Sistema Endócrino, Geniturinário, Sistema Respiratório, Sistema Nervoso Central, sendo os dois primeiros já validados por meio da técnica Delphi modificada. Considerou-se validados os itens para os quais o limite inferior do IC 95% foi superior ou igual a 4,0. O consenso sobre MPIs - Dor e inflamação foi constituído duas rodadas. Um grupo de nove especialistas atingiu consenso sobre 98 (63,2%) das 155 questões apresentadas: 31/34 preocupações independente do diagnóstico, 4/4 preocupações quanto à dose, 4/4 preocupações quanto a duração do tratamento, 19/20 preocupações quanto ao uso em condições específicas, 12/23 considerações especiais de uso e 28/68 alternativas terapêuticas. No consenso sobre MPIs -Sistema Cardiovascular, um grupo de sete especialista atingiu consenso sobre 84 das 257 questões apresentadas: 20/25 preocupações independente do diagnóstico, 4/4 preocupações quanto à dose, 37/57 preocupações quanto ao uso em condições específicas, 20/105 considerações especiais de uso e 3/66 alternativas terapêuticas. Embora a validação de listas de MPIs a partir da opinião de especialistas seja um processo complexo, a listas desenvolvidas poderão ampliar o conhecimento sobre MPIs no país, uma vez que são baseadas em consensos recentes. Desse modo, esta pesquisa possibilitará um melhor entendimento da magnitude do uso de MPIs no Brasil, e poderá contribuir para o desenvolvimento de estratégias e intervenções mais eficazes para a redução dos problemas relacionados ao uso de medicamentos em idosos no país.
The use of potentially inappropriate medications (PIMs) for older patients is a public health problem because it can compromise the effectiveness or safety of pharmacotherapy and is responsible for high rates of morbidity and mortality in this age group. Brazilian studies that investigated PIMs show that the prevalence of PIM use ranges from 28.0% to 82.6%. However, these studies used PIM lists developed in other countries in North America and Europe. The first Brazilian consensus on PIMs was published in 2016. Limitations reported by the authors included that the PIM list was based on previous versions of Beers (2012) and STOPP (2008), therefore, it did not include the most up-to-date versions published in 2015, and did not incorporate therapeutic alternatives. The aim of the present study is to develop and validate explicit criteria for the evaluation of PIMs prescribed to older patients in Brazil and their respective therapeutic alternatives. The development of this project comprises of two steps: 1- Elaboration of the preliminary PIM list for older patients based on a systematic literature review; 2 - Validation of the preliminary PIM list with the consensus of experts using modified Delphi technique; The elaboration of the preliminary list of MPIs was based on a systematic review of PIM lists published between January 1991 and April 2017. A qualitative analysis of the PIM lists was performed with the objective of verifying their applicability to the Brazilian market. This way, three lists of PIMs were selected: Beers’ 2015, STOPP 2015, and European Union (7) PIM. Thus, we obtained 153 explicit criteria distributed across seven instruments: PIMs–Pain and Inflammation, PIMs–Cardiovascular System, PIMs–Endocrine System, PIMs–Genitourinary, PIMs–Respiratory System, and PIMs–Central Nervous System. The first two were already validated using the modified Delphi technique. The items for which the lower limit of the 95% confidence interval (CI) was greater than or equal to 4.0 were considered to have been validated. The consensus on PIMs–Pain and Inflammation was formed by two rounds. A group of nine experts reached consensus on 98 (63.2%) of the 155 items. A consensus was reached for 31/34 concerns regardless of diagnosis, 4/4 dose concerns, 4/4 concerns about the duration of treatment, 19/20 concerns about use under specific conditions, 12/23 special considerations of use, and 28/68 therapeutic alternatives. In the consensus on PIMs–Cardiovascular System, a group of seven experts reached consensus on 84 of the 257 questions. A consensus was reached for 20/25 concerns independent of diagnosis, 4/4 concerns regarding dose, 37/57 concerns regarding use under specific conditions, 20/105 special considerations of use and 3/66 therapeutic alternatives. Although the development and validation of PIM lists based on expert opinion is a long and complex process, the development of PIM list based on recent consensuses will expand the knowledge about the PIMs in Brazil. Thus, this research will improve the understanding of the magnitude of PIM use in this country, and may contribute to the development of more effective strategies and interventions to reduce drug-related problems among older Brazilian patients.
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Nandala, Swathi. "Effects of Cisplatin Analog Size on the Reaction with DNA Bases." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1256.
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Cancer is the second leading cause of death in the United States. Cisplatin is one of the well-known anti-cancer agents used to treat testicular and ovarian cancers. It mainly binds to the DNA bases, which leads to cell death. The cytotoxic activity of the cisplatin analogs is due to the interaction of platinum with nucleotides like adenine at N7 or N1 position and guanine at N7 position. Guanine is the primary target for cisplatin analogs whereas adenine is the secondary target. Cisplatin analogs, [Pt(Me5dien)(D2O)]2+[Me5dien = N,N,N’,N’,N’’-pentamethyl diethylene triamine] and [Pt(dien)(D2O)]2+[dien=diethylene triamine] were synthesized and their effects on AMP and GMP were studied using NMR spectroscopy. The experiments were conducted to examine the effects of bulk on 5’-GMP and 5’-AMP. The results suggest that bulk slows down the reaction with AMP more than with that of GMP. The order of reactivity is Pt(dien)(GMP)> Pt(dien)(AMP) > Pt(Me5dien)(GMP) > Pt(Me5dien)(AMP). The reaction of the [Pt(Me5dien)(D2O)]2+ complex with AMP leads to multiple products, some of which appear to be due to coordination at N1 instead of N7.
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Neep, D. J. "The effect of reaction conditions on particle size in dispersion polymerisation." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/14095.
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Poly(styrene), poly(methyl methacrylate) and poly(butyl acrylate) dispersions have been prepared in methanolic media using partially hydrolysed poly(vinyl acetate)s, poly(vinyl pyrrolidone), poly(ethylene oxide) and poly(vinyl acetate) as steric stabilisers. The stabiliser concentration, molar mass of the stabiliser, initial solubility parameter of the continuous phase and initiator concentration were varied to investigate the effect that they had on the size of the particles produced. The initial solubility parameter of the continuous phase was varied by using methanol/water mixtures with different compositions. Particle size analysis was carried out by transmission electron microscopy(TEM), in association with image analysis, and laser diffraction particle size analysis. The results showed that dispersions had been produced with particle sizes from O.2-5.4μm in diameter for poly(styrene), from O.I-1.5lμm in diameter for poly(methyl methacrylate) and from O.2-1.8μm in diameter for poly(butyl acrylate). The standard deviation values calculated for the particle size measurements from the dispersions showed that a large number of the dispersions had narrow, or very narrow, particle size distributions.
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Jahanzad, Fatemeh. "Evolution of particle size distribution in suspension polymerisation reactions." Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/10300.
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Suspension polymerisation processes are commercially important for the production of polymer beads having wide applications. Polymers produced by suspension polymerisation can be directly used for particular applications such as chromatographic separations and ion-exchange resins. Particle Size Distribution (PSD) may appreciably influence the performance of the final product. Therefore, the evolution of PSD is a major concern in the design of a suspension polymerisation process. In this research, methyl methacrylate (MMA) has been used as a model monomer. A comparative study of MMA suspension polymerisation and MMNwater dispersion was carried out, for the first time, to elaborate the evolution of mean particle size and distribution. Polyvinyl alcohol (PVA) and Lauroyl Peroxide (LPO) have been used as stabiliser and initiator, respectively. Polymerisation experiments were carried out using a 1-litre jacketed glass reactor equipped with a turbine impeller and a condenser. The stabiliser, initiator and chain transfer concentrations, inhibitor concentration and type, reaction temperature, impeller speed, and monomer hold up were used as variables. A mathematical model was developed to predict the kinetics of polymerisation as well as the evolution of PSD by population balance modelling. The experimental results were compared with the model predictions. From the comprehensive experimental results, the characteristic intervals of a typical suspension polymerisation were realised as: 1) Transition stage during which PSD narrows dramatically and drop size decreases exponentially due to higher rate of drop break up in comparison with drop coalescence . _ until a steady state is reached. The importance, and even the existence, of the transition stage have been totally ignored in the literature. The results indicate that increasing the impeller speed, and PV A concentration will lead to a shorter transition period. Also increasing the rate of reaction, via increasing initiator concentration, and reaction temperature will shorten this period. ABSTRACT 2) Quasi steady-state stage during which the rate of drop break up and drop coalescence are almost balanced leading to a steady-state drop size and distribution. The occurrence of this stage is conditional. Low impeller speed and PV A concentration may remove the quasi steady-state stage completely and drops may start growing considerably after a sharp decrease in size during the transition stage. 3) Growth stage during which the rate of drop break up considerably falls below the rate of drop coalescence due to the viscosity build up in drops leading to drop enlargement and PSD broadening. Results show that the onset of the growth stage may not be fixed and it depends on the balance of the forces acting on drops. The onset of the growth stage in terms of time was advanced with decreasing stirring speed and PV A concentration and increasing monomer hold up. Under a static steady state, which is formed when a high concentration of PV A is used, there is almost no growth. 4) Identification stage during which a solid-liquid suspension is attained and the PSD and mean particle size remain unchanged afterwards. The onset of this stage appears to be fairly constant for different formulations. The developed model could fairly predict the rate of polymerisation. It was also capable of predicting the evolution of particle size average and distribution qualitatively in the course of polymerisation. The results can be used as a guideline for the control of particle size and distribution in suspension polymerisation reactors. A more quantitative exploitation of the model has been left for a future research.
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Birrell, James Alexander. "The mechanisms of flavin site reactions in NADH:ubiquinone oxidoreductase." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607665.
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Jarernsiripornkul, Narumol. "Pharmacist input into patients' self-reporting of adverse drug reactions." Thesis, Robert Gordon University, 1999. http://hdl.handle.net/10059/2717.
Full textAbstract:
Adverse drug reactions (ADRs) are common and should be reported to the CSM, particularly for newly marketed drugs. There is under-reporting of ADRs by doctors. Involving the patient in self-reporting, particularly when initiated by pharmacists is feasible and could help to improve reporting rates. This study investigated a comprehensive checklist questionnaire listed symptoms in all body systems to facilitate patient self-reporting using both established and new 'black triangle' centrally-acting drugs. Symptoms reported were compared to their documentation in medical notes and for new drugs to reports from other sources. A novel classification system for ADRs was developed to take account of the minimal data available and used to evaluate the potential accuracy of symptom attribution by patients. An external comparison of a sample of symptom classifications by an ADR expert was also obtained. The questionnaire was sent to 464 patients prescribed carbamazepine, sodium valproate, trazodone, doxepin and co-proxamol from three participating medical practices in a pilot study. Subsequently, it was sent to all patients (n=2307) prescribed tramadol, fentanyl patch, venlafaxine, nefazodone, citalopram, moclobemide, gabapentin, lamotrigine and topiramate from 79 participating medical practices in Grampian during January-March 1997. The overall response rates were 44.6% (n=207) for the pilot study and 36.3% (n=837) for the main study. The most frequently reported symptoms were: drowsiness for carbamazepine, unusual tiredness for sodium valproate, constipation for co-proxamol, dry mouth for trazodone, doxepin, tramadol, venlafaxine, nefazodone, moclobemide and citalopram, weight gain for gabapentin, loss of memory for lamotrigine, weight loss for topiramate and constipation for fentanyl patch. Overall only 22.4% (522/2330) of symptoms reported by patients were recorded by GPs in the 310 medical notes accessed. In general, common symptoms were reported more frequently by patients than in CSM reports and PEM data. Patients tended to report minor and known ADRs which bothered them, while CSM and PEM reports received were of more severe ADRs. Respondents were more likely to report symptoms (6040/8630,70%) potentially caused by the study drugs than those not to be caused by the study drugs. Moderate agreement (Kappa = 0.4-0.5) was found between expert and researcher classifications of symptom causality. It is suggested that interpretation by pharmacists of patient self-reporting using the checklist questionnaire could result in much higher ADR reporting rates, in particular for new drugs.
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Hu, Kuo-Juei. "Structural variation of size-selected metal clusters in chemical reactions." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6566/.
Full textAbstract:
This thesis is comprised of studies in the characterisation of monolayer-protected and metal cluster of the structural response of size-selected (bare) clusters to chemical reactions. The technique employed is high-angle annular dark field (HAADF) aberration-corrected scanning transmission electron microscopy (AC-STEM). The effect of chemical reactions on size-selected metal clusters was investigated. The clusters under investigation were imaged with AC-STEM and their structure was assigned by comparing the atomic resolution images with a set of multi-slice STEM image simulation atlases. The effect of vapour-phase 1-pentyne hydrogenation on size-selected Aux (x=923 and 2057) cluster was studied and it was found that the gold nanoclusters demonstrate high stability in both size distribution and structure under the reaction. On the contrary, size-selected Pdx (x=923 and 2057) clusters tended to transform from amorphous to high symmetry structures under the same reaction condition. The gas-phase CO oxidation reaction on size-selected Aux (x=561, 923 and 2057) cluster was studied with regard to cluster size distribution and atomic structure. It was found that under the same conditions of the CO oxidation reaction, two different kind of ripening modes could be identified depended on the cluster size. Smoluchowski ripening, in which clusters diffuse intact and coalescence, is found to occur for Au2057 in the CO oxidation reaction. Ostwald ripening, in which larger clusters grow at the expense of smaller ones, was found to occur for Au561 and Au923 clusters, due to the extra energy generated from catalytic CO oxidation reaction.
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Lamichhane, Hari Prasad, and Hari Prasad Lamichhane. "Calculated Vibrational Properties of Quinones in Photosynthetic Reaction Centers." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/phy_astr_diss/51.
Full textAbstract:
This dissertation presents a detailed computational investigation into the vibrational properties of quinones involved in solar energy conversion processes in photosynthetic reaction centers. In particular, we focus on the vibrational properties of the ubiquinone molecule that occupies the QA binding site in purple bacterial photosynthetic reaction centers.
To provide a foundation upon which to base computational studies of pigments in protein binding sites density functional theory based calculations of the vibrational properties of neutral ubiquinone in the gas phase and in solvent were undertaken. From single point energy calculations it was shown that at least eight ubiquinone conformers, each with slightly different FTIR spectra, could be present in solvent at room temperature.
The calculated and experimental spectra for neutral ubiquinone in solution are very different from the spectra associated with ubiquinone in the QA binding in purple bacterial reaction centers. For this reason an ONIOM method was undertaken in which the pigment was treated using density functional theory based methods while the protein was treated using molecular mechanics. The ONIOM calculations not only modeled the experimental QA FTIR difference spectra but also resolved the long standing issue of whether a very strong hydrogen bond exists between the bound ubiquinone and the imidazole nitrogen of a histidine residue (HisM219).
To further validate the usefulness of the ONIOM approach experimental isotope edited FTIR spectra obtained using purple bacterial reaction centers with a range of chainless symmetrical quinones incorporated were modeled. Again, the agreement between the calculated and experimental spectra is outstanding.
We also modeled the vibrational properties of the ubisemiquinone anion radical both in solvent and in the QA binding site. Vibrational modes of ubisemiquinone display a greater degree of mixing of the various molecular groups of the molecule. Nonetheless the calculated FTIR spectra for ubisemiquinone in solution and in the QA site agree very well with that found experimentally. Vibrational frequencies of ubisemiquinone obtained from ONIOM calculated Raman spectra also agree very well with that found in experimental resonance Raman spectra associated with the ubisemiquinone anion radical in the QA binding site.
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Crump, Brian R. "Kinetic study of the mechanism and side reactions in the hydrogen peroxide based production of chlorine dioxide." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/11322.
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Chen, Yuan-Han. "The active site chemistry of factor inhibiting HIF-1, coordination, bonding, and reaction." Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/dissertations/AAI3372258/.
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Nicola, Floyd. "A novel glycoconjugation method and unexpected photo-induced site-selective protein cleavage reaction." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:aac2cbe4-76be-4238-b0ce-ce31f371cb74.
Full textAbstract:
Homogenous glycoforms of glycoproteins are one of the primary targets in glycobiology to allow for the determination of glycoprotein function and to create glycoprotein mimetics for use as therapeutic agents. Although N- and O-linked glycosylation is preferred in nature, S-linked glycoproteins are attractive synthetic targets due to their enhanced chemical stability and enzymatic resistance. This thesis reports a novel convergent method for the synthesis of S-linked glycoproteins through the site-specific ligation of 1-glycosyl thiols to olefin containing proteins. This strategy employs unnatural amino acid incorporation for the introduction of L-homoallylglycine (L-Hag) into proteins and free-radical addition hydrothiolation chemistry, under conditions mild enough to preserve protein activity. The unique reactivity profile of L-Hag, which has an olefinic side-chain, compared with the natural amino acids characteristically found in proteins, allows for a chemoselective chemical reaction. At the outset, methodology was optimised using Hag as a model system. The reaction was then successfully applied to proteins with different structures, for precise, site-selective glycoconjugation at single and even multiple sites. Whilst investigating the above-mentioned photochemical modification of proteins, an unexpected photo-induced site-selective protein cleavage reaction localised to the TIM-barrel proteins from family 1 of glycosylhydrolases was discovered. Although proteins are known to be affected by UV irradiation, examples of clean, site-selective photocleavage without the use of a cleaving agent are rare. Remarkably, the β-glycosidase from Sulfolobus solfataricus (SsβG) was found to form two daughter fragments following UV irradiation (240–308 nm). Alterations at and alaninescanning of a sphere of residues around the cleavage site were used to establish which residues were essential for the reaction to occur and extensive analysis of the fragments allowed a reaction mechanism to be proposed. The propensity of other proteins to undergo photo-induced cleavage was also investigated. In addition, the biotechnological utility of the aforementioned photocleavage reaction has been applied to the development of a cleaved-tag affinity purification method using a GFPSsβG fusion as the model protein.
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Zellweger, Christoph. "Reactive nitrogen (NOy) at the high-alpine site Jungfraujoch /." [S.l.] : [s.n.], 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13461.
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Brunet, Nathalie. "Reactions of CpW(NO)(CH₂SiMe₃)₂ with Lewis acids : characteristic chemistry of CpW(NO)(CH₂SiMe₃)(CH₂CPh₃)." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27835.
Full textAbstract:
The nitrosyl complex CpW(NO)R₂ (R = CH₂SiMe₃) forms 1:1 adducts via isonitrosyl linkages to Lewis acids such as AlMe₃ and Cp₃Er, i.e. CpWR₂(NO→A) (A = AlMe₃, ErCp₃). These adducts regenerate the starting dialkyl complex when treated with water. Protonation of CpW(NO)R₂ by HBF₄⋅0Me₂ can also be effected. Whether the site of protonation is the nitrogen or the oxygen atom of the nitrosyl ligand is not known with certainty, although O-protonation is postulated by analogy with the other Lewis-acid adducts of CpW(NO)R₂. In these adducts, the nitrosyl stretching frequency is shifted to lower wavenumbers relative to that of the parent dialkyl, to an extent which increases as harder Lewis acids are employed. The colour of the adducts also ranges from red to orange to yellow as progressively harder acids are used.
Treatment of CpW(NO) (CH₂SiMe₃)₂ with [Ph₃C]⁺ PF₆⁻ in Ch₂CL₂ results in electrophilic cleavage of a carbon-silicon bond to yield the mixed dialkyl CpW(NO)(CH₂SiMe₃)(CH₂CPh₃), which has been fully characterized by spectroscopic methods and by a single-crystal X-ray crystallographic study. The formation of Me₃SiF and PF₅ (coordinated to Lewis bases in the reaction mixture) as by-products of this reaction has been confirmed by ³¹P and ¹⁹F NMR spectroscopy of the reaction mixture in CD₂CL₂. Preliminary attempts to extend this novel reaction of a silicon-containing ligand by using other carbocations were unsuccessful. This is attributed to the high reactivity of the required carbocations and the large number of possible reaction sites on the metal complex. Some reactions of the mixed dialkyl CpW(NO)RR¹ (R = CH₂SiMe₃ R¹ = CH₂CPh₃) were found to be analogous to those of the parent CpW(NO)R₂, while other reactions followed a different course because of the ability of the CH₂CPh₃ ligand to orthometallate. Thus, CpW(NO)RR¹ is much less thermally stable than CpW(NO)R₂. As a solid or a solution in non-coordinating solvents, it decomposes in a matter of days at room temperatures to a mixture of products which were not identified. In acetonitrile solution, an orthometallated complex derived from CpW(NO)RR¹ can be trapped by coordination of solvent. The product CpW(NO)(CH₂C(C₆H₄)Ph₂)(NCMe) has been isolated and crystallographically characterized. Cyclic voltammograms of CpW(NO)R₂ and CpW(NO)RR¹ show that both complexes undergo an apparently chemically reversible reduction and an irreversible oxidation. The mixed dialkyl CpW(NO)RR¹ is somewhat easier both to reduce and to oxidize than CpW(NO)R₂.
Like CpW(NO)R₂, CpW(NO)RR¹ reversibly forms a 1:1 adduct with PMe₃.
Also analogously to CpW(NO)R₂, it reacts with 0₂ to form a 5:1 mixture of
dioxoalkyl complexes CpW(0)₂R and CpW(0)₂R¹, and with NO(g) to form 2
CpW(NO)R¹(ƞ² -0₂N₂R). In this product, insertion of NO has occurred
exclusively in the W-CH₂SiMe₃ bond. Upon photolysis, both complexes
CpW(NO)R¹¹(ƞ²-0₂N₂R) (R¹¹ = CH₂SiMe₃ or CH₂CPh₃) form dioxo alkyls CpW(O)₂R¹¹ in an unprecedented reaction.
The ability of CpW(NO)RR¹ to orthometallate also results in the
formation, when this complex is treated with sulphur, of CpW(O)(CH₂C(C₆H₄)Ph₂)-(SR). No analogue to this compound can be obtained from reaction of CpW(NO)R₂ with sulphur. The sequence of reactions leading to the formation of this product is not known.Science, Faculty of
Chemistry, Department of
Graduate
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Shmelin, George. "A new rheological polymer based on boron siloxane cross-linked by isocyanate groups." Thesis, University of Hertfordshire, 2012. http://hdl.handle.net/2299/13901.
Full textAbstract:
The research described in this thesis originated from an idea to develop new body protection for the sport of fencing. The ultimate goal is to develop body armour which would be flexible, wearable, washable, light and breathable, offer protection from injuries and cover the entire body of a sportsman. A new material which exhibits shear thickening behaviour has been specially developed for this purpose in the process of this investigation. The material was designed and synthesised as a soft polymeric system which is flexible, chemically stable and able to increase the value of its modulus of elasticity upon impact at a high strain rate, while remaining in its soft gel-like elastomeric state when low strain rate deformation is applied. The polymeric system that has been developed is based on interpenetrating polymeric networks (IPN) of immiscible polyurethane/urea-ester/ether and poly(boron)n(dimethylsiloxane)m (where on average m ≈ 16 n). In addition, as the polydimethylsilane (PDMS) based polymeric system strongly tends to phase separation, the siloxane polymeric network was chemically cross-linked to the polyurethane polymeric network through polyurethane chemical cross-link-bridges. In order to introduce polyurethane cross-links to a siloxane-based polymeric network, some of the attached methyl groups in the PDMS polymeric backbone were substituted by ε-pentanol groups. The resulting polymeric system combines properties of an alternating copolymer with IPN. The actual substitution of the methyl groups of PDMS into alternating ε-pentanol groups was performed by Grignard reaction of trifunctional chlorosilane monomers, magnesium and 1,5-dibromopentane. Chemical analytical techniques like FT-IR, 13C NMR and 1H NMR spectroscopy were used to reveal the chemical structure of the synthesised polymeric network. The mechanical and dynamical properties of the obtained polymeric system were analysed by dynamic mechanical analysis (DMA). This part of the investigation indicated that the novel polymeric system exhibited shear thickening behaviour, but only at a narrow diapason of deformations (i.e., deformations between 2 to 3 % of the length of the sample). At this limited diapason of deformation an effective increase of the modulus of elasticity from 6 MPa (at lower frequencies, i.e., up to ≤6 Hz of the applied oscillating stress) to 65 MPa (at frequencies between 12.5 to 25 Hz) was obtained. However, no increase in the modulus of elasticity was recorded at deformations below 1.5 % or above 3.5 % of length of the sample at the same frequencies (0 to 25Hz) of the applied oscillating stress.
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ELACHAWI, SAKHER. "Les reactions parodontales dans le site d'extraction au cours du deplacement orthodontique." Paris 7, 1991. http://www.theses.fr/1991PA07GS01.
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Yang, Lichen. "Studies on Site-Selective C-H Borylation Reactions of Arenes and Heteroarenes." Kyoto University, 2020. http://hdl.handle.net/2433/253291.
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Allan, Charlotte Sarah Moreis. "Computational mechanistic and stereochemical studies of single-site polymerisation catalysts and reactions." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/6160.
Full textAbstract:
Computational investigations into four metal-centred polymerisation catalysts are presented. The work investigates how and why the catalysts behave as they do, focusing on specific interactions within the catalyst structure itself and also on the transition states involved in the polymerisation reactions. Density functional theory has been used to examine the effect of the metal, the role of the ligand and the interplay between the two. Each study addresses particular mechanistic and structural questions that have been raised during experimental investigations and that are difficult to answer experimentally. Chapter one provides a general overview of computational techniques used in chemical modelling. The specific methods used in this work are presented as well as a brief review of modern trends. Chapter two investigates an unusual pair of metal-hydrogen interactions in a tin bis(triazenide) complex. We have termed this double M-H interaction “bifurcated” and compared other systems in which this interaction is present (and often unidentified). A variety of computational techniques are used to analyse the nature of the interactions both in qualitative and quantitative terms. The third chapter investigates the mechanism of alkyl transfer in a magnesium bis(imino)pyridine complex. A number of mechanistic pathways are explored to explain the original report of non-electrophilic alkylation at a pyridine nitrogen. We consider in particular how the solvent and the role of other species in the reaction mixture may influence the mechanism. Chapter four describes the inversion of configuration occurring in a pseudo-C3- symmetric zirconium tris(phenolate) complex. Variable temperature NMR spectra and simulations complement DFT calculations to explore the mechanism of inversion. We question the long-held assumption that the inversion process is concerted. In chapter five, the polymerisation of rac-lactide by an aluminium salen-type system is investigated in detail through characterisation of the transition state structures. Specifically, we have aimed to explain the different behaviour of two structurally similar catalytic species’ which produce polymer of different tacticity. Application of a variety of additional computational techniques in a number of these studies supplements the density functional calculations. They provide insight into specific interactions in both starting materials and transition states and detailed information about the reaction mechanisms.
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Richter, Karsten [Verfasser]. "Film formation, side reactions and interactions in Si/C negative electrodes in Lithium ion batteries / Karsten Richter." Ulm : Universität Ulm, 2020. http://d-nb.info/1222109301/34.
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Lorenzo, Maria Ortega. "Complexities and dynamics of the enantioselective site in heterogeneous catalysis : tartaric acid and methylacetoacetate on Cu(110)." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366724.
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陳磊碩 and Lui-sek Chan. "Chemical modification of immunoglobulins and the effects on antigen binding site affinity." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B29913378.
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Chan, Lui-sek. "Chemical modification of immunoglobulins and the effects on antigen binding site affinity /." [Hong Kong] : University of Hong Kong, 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13731506.
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Hlabangana, Ntandoyenkosi. "Influence of particle size and morphology of Pt₃Co/C on the oxygen reduction reaction." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/24324.
Full textAbstract:
Polymer electrolyte fuel cells have shown great potential in providing clean energy with no emissions. The kinetics of the cathode reaction, i.e. the oxygen reduction reaction (ORR) are sluggish necessitating high loadings of the catalyst metal, i.e. platinum. Platinum is a limited resource and expensive. Its price has been one of the major drawbacks in wide scale commercialisation of fuel cells. In an effort to improve the activity of the catalyst and therefore reduce Pt loadings on the catalyst, Pt can be alloyed with transition metal elements (e.g. Ni, Co and Fe) to form bimetallic catalysts. Alloying has been known to improve the activity and stability of a catalyst for the ORR. The enhanced activity of the alloys originates from the modified electronic structures of the Pt in these alloy catalysts which reduces the adsorption of spectator species therefore increasing the number of active sites for the ORR (Wang et al., 2012 (2)). The aim of this study was to gain a better understanding of the influence of Pt alloy particle size and active surface morphology on the ORR activity. The Pt alloy that was investigated was Pt₃Co/C. The surface morphology was modified by varying the Pt/Pt₃Co loading on a carbon support. The catalysts were prepared using thermally induced chemical deposition. The support used was Vulcan-XC-72R. The effects of varying the metal loadings on the ORR was investigated. The loadings that were investigated were 20, 40, 60 and 80 wt. % Pt and Pt₃Co. The alloy catalysts were subjected to annealing at 900 °C and acid leaching. The catalysts were analysed using electrochemical characterisation techniques such as cyclic voltammetry, CO stripping voltammetry, rotating disk electrode and rotating ring disk electrode. Physical characterisation of the catalysts was also implemented. The techniques used were x-ray diffraction, thermogravimetric analysis and transmission electron microscopy. The Pt particles on the carbon support were found not to agglomerate significantly despite the loading being increased. This trend was also observed for the Pt₃Co/C catalysts even after heat treatment and leaching. The lack of agglomeration was credited to a new reactor system developed in this work. The particle growth increased from low loadings to high loadings for both the Pt/C and Pt₃Co/C catalysts. Particle growth was more significant for the Pt₃Co/C catalysts at high loadings. At lower loadings (20 and 40 wt. %) the particle sizes between the Pt/C and Pt₃Co/C catalysts were comparable despite the Pt₃Co/C catalysts undergoing annealing and leaching. The mass specific activity of the Pt/C catalysts was not improved by alloying with the exception of the 20 wt. % catalyst which saw an enhancement factor of 1.66. The surface specific activity of the Pt/C catalysts was improved significantly with factors of 2.40 and 3.11 being recorded for the 20 and 80 wt. % Pt₃Co/C catalysts respectively. The enhancement factors of the intermediate loadings (40 and 60 wt. %) were lower and fairly similar at 1.30 and 1.35 respectively.
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Murray, George M. "Acrosome size and kinematics of human spermatozoa." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/1131.
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Van, Wyk Marius. "Verification of leakage through the side reflector graphite of the PBMR reactor / Marius van Wyk." Thesis, North-West University, 2004. http://hdl.handle.net/10394/543.
Full textAbstract:
As a result of manufacturing and temperature constraints of the reactor core components,
leakage flow is an inevitable, and generally undesirable, occurrence within the PBMR
reactor. Leakage flow occurs between the narrow gaps of the graphite blocks within the
Core Structures as a result of the large pressure gradient over the pebble bed.
The PBMR utilizes computational fluid dynamics (CFD) codes for the simulation of flow and
heat transfer through the reactor. Due to hardware limitations, it is not yet possible to model
the leakage paths between the graphite blocks of the reactor CFD model in detail since, in
some locations the leakage paths are in the order of 175-micron in width and would require a
very fine mesh structure. It is therefore required to simplify some of the more complex
leakage flow paths with the use of a porous medium sub-model.
In order to calibrate the porous medium sub-model to produce similar flow resistance as the
detail leakage path, it is necessary to separately model the complex leakage path in detail,
using CFD to determine the actual flow resistance characteristics as function of leak flow rate
and helium density. There was a wide spread in the calculated Reynolds numbers
throughout the flow path of the detail leakage paths, and it was uncertain whether the
leakage flow was laminar, in the transition zone or turbulent. This raised uncertainty with
regards to the accuracy of the CFD models of the detail leakage paths.
An experiment was devised that contained all the flow phenomena of the actual detail
leakage paths within the reactor, and was used to validate the numerical CFD modelling of
the helium flow through the side reflector leakage paths. Three leakage gap sizes, 175, 280
and 380-micron were experimentally tested. The experiments were simulated with CFD and
it was found that there was a good correlation between the laminar CFD results in both the
175 and 280-micron gap sizes.
It was finally concluded that the detail leakage path CFD models were correctly modelled as
laminar.Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.
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Fort, Emily Minatra. "A historical site assessment of the Georgia Tech Research Reactor." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/17257.
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Deitermann, Michael. "Semisynthese von Reactive-site- und Backbone-Varianten des Trypsin-Kallikrein-Inhibitors." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=966019180.
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Rajapakse, Achula, and s9508428@student rmit edu au. "Drop size distribution and interfacial area in reactive liquid-liquid dispersion." RMIT University. Civil Environmental and Chemical Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080717.163619.
Full textAbstract:
Emulsion explosives have become the preferred choice as blasting agents for numerous industries including mining, agriculture, and construction. One of the most important components in such an emulsion is an emulsifier, which controls the emulsification properties of the explosive. The present study involves the production of one such emulsifier, which is produced by reacting two immiscible liquids, PIBSA (polyisobutylene succinic anhydride) and MEA (monoethanolamine). The study examines the effect of design variable such as the impeller speed, impeller type and the dispersed phase volume fraction on interfacial area. Experiments were carried out in a 0.15 m diameter fully baffled stirred tank using a 6-bladed Rushton turbine impeller and a marine propeller. Drop size was determined using a microscope with a video camera and image processing system. The transient concentration of PIBSA was determined using FTIR analysis and used to estimate the volume fraction of the dispersed phase (Ö). The effective interfacial area was calculated using the Sauter mean drop diameter, d32 and Ö. Impeller speeds ranging from 150 to 600 rpm and dispersed phase volume fractions, Ö ranging from 0.01 to 0.028 were examined in the experimental study. It was found that that the evolution of Sauter mean drop diameter, d32 has four different trends depending on Ö and impeller speed. At high impeller speeds and high Ö, d32 values decrease initially and reach constant values after a long period of time. This trend is consistent with the findings in previous investigations. Under certain operating conditions, d32 values increase initially with stirring time to reach a maximum value and then decrease to reach a steady state value. The presence of these trends has been attributed to the effect of changing physical properties of the system as a result of chemical reaction. Results indicate that, in general, Sauter mean drop diameter d32 decreases with an increase in agitation intensity. However a decrease in the dispersed phase volume fraction is found to increase d32. These trends are found to be the same for both impeller types studied. Comparing the drop size results produced by the two impellers, it appears that low-power number propeller produces s ignificantly smaller drops than the Rushton turbine. It was found that the concentrations of reactants decrease with time for all impeller speeds thereby leading to a decrease in interfacial area with the progress of the reaction. Interfacial area values obtained at higher impeller speeds are found to be lower in spite of lower d32 values at these speeds. Also, these values decrease with time and become zero in a shorter duration indicating the rapid depletion of MEA. The interfacial area values obtained with the propeller at a given impeller speed are lower as compared to those for Rushton turbine. They also decrease and become zero in a shorter duration as compared to those for Rushton turbine suggesting propeller¡¦s performance is better in enhancing the reaction rate.