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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

Separação de piperonal contido em uma solução de síntese a partir do óleo essencial de Piper hispidinervum C. CD. por cromatografia líquida de alta eficiência com injeção empilhada / Separation of piperonal of synthetic solution from a Piper hispidinervum essential oil by high perfomance liquid chromatography with stacked injection

Ramos, Alex Martins, 1981- 12 December 2014 (has links)
Orientador: Marco Aurélio Cremasco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T20:23:51Z (GMT). No. of bitstreams: 1 Ramos_AlexMartins_D.pdf: 2631980 bytes, checksum: 6ae843a3d8311ad1d248269d9eb22659 (MD5) Previous issue date: 2014 / Resumo: O piperonal é uma molécula de grande valor econômico, pois é utilizado como matéria-prima nas indústrias de cosméticos e de fármacos. Uma das formas de obtenção do piperonal é por meio de síntese cujo substrato é o safrol. O safrol é o principal constituinte químico do óleo essencial de pimenta-longa (Piper hispidinervum, C. DC), espécie que é abundante na região Amazônica. Após os processos de síntese aplicados diretamente no óleo de pimenta longa, obtém-se o piperonal, como produto principal, e os coprodutos safrol, isosafrol glicol, cis-isosafrol, trans-isosafrol e terpinoleno. O rendimento dessa rota sintética é cerca de 84% de piperonal. Por este motivo, e considerando o alto valor agregado ao piperonal é que se propôs separá-lo por cromatografia líquida de alta eficiência (CLAE) com injeção empilhada. Nesse tipo de separação são essenciais as definições de tempo de ciclo e tempo de coleta. Para isso, foram empregadas duas abordagens: a abordagem experimental, na qual o tempo de ciclo e o tempo de coleta foram obtidos diretamente do cromatograma e a abordagem teórica que surgiu em decorrência do modelo proposto nesta Tese, onde os tempos de ciclo e coleta foram obtidos a partir dos parâmetros da curva gaussiana. Para essa última abordagem, são necessárias as constantes de equilíbrio e os parâmetros de transferência de massa (Dp, Def, Ds e Eb), que foram obtidos experimentalmente. Foram empregados três sistemas cromatográficos de separação: o primeiro e segundo foi constituido de fase móvel acetonitrila/água ¿ 70/30 (v/v) a 25 e 35 oC e o terceiro, de fase móvel etanol/água ¿ 70/30 (v/v) a 35 oC, com detecção em 245 nm para todos os sistemas. Utilizou-se coluna analítica de 25 x 0,46 cm e coluna semipreparativa de 25 x 1,0 cm recheadas com fase estacionária C18 cujo tamanho médio de partícula foi 20 ?m. Na coluna analítica foram determinadas a porosidade total e as constantes de equilíbrio do piperonal, safrol, isosafrol e terpinoleno, nas vazões de 0,6 ¿ 1,4 mL.min-1. Na coluna semipreparativa foram determinadas a porosidade total bem como os parâmetros de transferência de massa, nas vazões de 4,0 ¿ 6,0 mL.min-1. Para realização da abordagem teórica, foi preparado uma solução na qual a concentração foi de 0,2 g.L-1. Já na abordagem experimental, preparou-se uma solução de 9,50 g.L-1. Os resultados quanto aos parâmetros cromatográficos e às constantes de equilíbrio mostraram que os componentes têm a seguinte ordem crescente de eluição: piperonal, safrol, isosafrol e terpinoleno. O piperonal tem a menor afinidade com a fase estacionária C18 enquanto o terpinoleno possui a maior. Quanto aos parâmetros de transferência de massa, todos os valores foram próximos àqueles previsto na literatura, sendo o coeficiente de difusão efetivo da ordem de 10-6 cm2.s-1 e o coeficiente de dispersão axial da ordem de 10-3 cm2.s-1. Em relação à abordagem experimental, o piperonal apresentou pureza e recuperação superiores a 98% e 97%, respectivamente, em que a fase móvel acetonitrila/água à 25 oC, constitui-se como o melhor sistema de separação. O mesmo resultado foi obtido para a abordagem teórica quanto ao sistema de separação, sendo a pureza e recuperação de aproximadamente 100% de piperonal. A CLAE semipreparativa com injeção empilhada mostrou-se bastante eficiente em termos de produção de piperonal com elevado grau de pureza. Os resultados indicaram também que uma quantidade maior de amostra pode ser injetada e as informações operacionais bem como os parâmetros determinados neste estudo podem ser facilmente implementados em cromatografia preparativa, tanto em batelada quanto contínua, para obter grandes quantidades de piperonal puro / Abstract: Piperonal is a molecule of great economic value because it is used as raw material in the cosmetic and pharmaceutical industries. One way of obtaining piperonal is through synthesis which substrate is safrole. Safrole is main constituents of the essential oil of long pepper (Piper hispidinervum, C. DC), specie that is abundant in Amazon region. After synthesis processes applied directly to the long pepper oil, piperonal is obtained as the main product and coproducts safrole, isosafrole glycol, isosafrole cis, trans-terpinolene, and isosafrole. The throughput for this synthetic route is about 84% of piperonal. For this reason, and considering the high added value at the piperonal is proposed that separate it by High Performance Liquid Chromatography with stacked injection. For this, two approaches were used: the experimental approach, in which the cycle time and the time of collection were obtained directly from the chromatogram in concentrated solution and the theoretical approach that arose due to proposed model in the thesis on condition of infinite dilution, where cycle times and collection were obtained from the parameters of the gaussian curve. In this last approach, the equilibrium constants and parameters of mass transfer (Dp, Def, Ds and Eb), which were obtained experimentally are needed. Três chromatographic separation systems were used: the first and second, consisted of mobile phase acetonitrile/water ¿ 70/30(v/v) at 25 and 35 oC and the third, ethanol/water ¿ 70/30 (v/v) at 35 oC, with detection in 245 nm all systems. It was used analytical column of 25 x 0,45 cm and semipreparative column of 25 x 1,0 filled with stationary phase C18 which size particle is 20 ?m. In analytical column were determined the total porosity and equilibrium constants of piperonal, safrole, isosafrole and, terpinoleno, in flow rate of 0.6 ¿ 1.4 mL.min-1. In semipreparative column were determined the total porosity as well as the parameters of mass transfer, in flow rates 4.0 ¿ 6.0 mL.min-1. For the performance of theoretical approach, was prepared a solution in which the concentration 9.50 g.L-1. The results regarding to chromatographic parameters and equilibrium constants showed that the components has a followed ascending order of elution: piperonal, safrole, isosafrole, terpinolene. The piperonal has a lowest affinity in respect to stationary phase C18 while terpinoleno has the greatest. Regarding mass transfer parameters, all values are close to those predicted in the literature, the effective diffusion coefficient of about 10-6 cm2.s-1 and the axial dispersion coefficient of the order of 10-3 cm2.s-1. With respect to experimental approach, piperonal presented purity and recovery greater than 98% and 97%, respectively, in which mobile phase acetonitrile/water at 25 ° C, was established as the best separation system. The same result was obtained to theoretical approach regarding to separation system, being purity and recovery about 100% of piperonal. The semipreparative HPLC with stacked injection proved to be very efficient in terms of producing piperonal with high purity. The results also indicate that a greater amount of sample may be injected, and the operational information¿s and the parameters determined in this study may be easily implemented in preparative chromatography, either batch or continuous, to obtain large quantities of pure piperonal / Doutorado / Engenharia de Processos / Doutor em Engenharia Química
342

Relação entre hábito alimentar e síndrome do espectro autista / Relationship between food habits and autistic spectrum

Nádia Isaac da Silva 14 March 2011 (has links)
O autismo é uma síndrome que afeta todas as áreas do comportamento humano. Sua etiologia não está definida. Os estudos descreveram uma associação do autismo com diversas anormalidades fisiológicas entre elas, distúrbios relacionados ao metabolismo proteico. A teoria do excesso de peptídeos opioides afirma que o consumo de glúten e caseína pode intensificar o comportamento da síndrome do espectro autista. Outra hipótese é de que distúrbios do metabolismo da creatina também estão integrados à doença. Os objetivos desse estudo foram: avaliar a variedade e a frequência de alimentos consumidos por autistas, bem como a adequação desse consumo; avaliar as alterações do metabolismo da creatina; desenvolver testes preliminares para determinar as condições mais adequadas para a identificação e possível quantificação dos peptídeos opioides derivados do glúten e da caseína por HPLC. Para atingir esses objetivos foi elaborada uma anamnese nutricional, contendo questões sobre características sócio-demográficas das famílias dos autistas participantes, histórico pessoal de doenças, comportamento autista durante as refeições, e levantamento de hábito alimentar. Para caracterizar o quadro clínico da população foi realizada uma avaliação psicológica com aplicação do método quantitativo Childhood Autism Rating Scale (CARS) e a identificação de presença de retardo mental foi através de levantamento de avaliação clínica existente, feita por equipe multidisciplinar das instituições participantes. A concentração de creatinina na urina dos autistas e grupo controle formado por parentes do mesmo sexo foi determinada pelo método de Jaffé. Os resultados sobre a caracterização da população indicaram que 1/3 dos pais de autistas possuem baixa escolaridade e 60% renda familiar na faixa de 2 a 4 salários mínimos. Segundo o método de avaliação CARS 64% dos autistas são casos graves. A renite alérgica é a patologia de maior prevalência na população estudada. Em média 60,71% dos autistas apresentam sintomas gástricos, sendo o mais frequente a flatulência (39,90%). O registro sobre comportamento alimentar identificou que 50% dos autistas expressam o comportamento de comerem muito rápido e 46,43% consomem porções exageradas de alimentos. Esse fato influência diretamente o hábito alimentar. A avaliação de adequação de consumo de nutrientes revelou que 57,14% têm o consumo de energia superior ao recomendado e baixo consumo de fibras, ácido ascórbico e cálcio. As análises de concentração de creatinina revelaram que os valores são significativamente inferiores em crianças autistas e do grupo controle formado por parentes distantes e que são similares quando comparado com grupo formado por seus pais. As análises iniciais por cromatografia líquida de alta performance evidenciam que dos dois métodos desenvolvidos o codificado como número 2 é mais eficiente do que o número 1, pois consegue distinguir os picos de todos os padrões de peptídeos testados e que o protocolo inicial para a extração de peptídeos opioides em fase sólida deve ser revisto. / Autism is a syndrome that affects all areas of human behavior. Its etiology is not defined. The studies described an association of autism with various abnormalities including physiological disorders related to protein metabolism. The theory of excess opioid peptides says that consumption of gluten and casein can intensify the behavior of autistic spectrum syndrome. Another hypothesis is that disorders of creatine metabolism are also integrated to the disease. The objectives of this study were to assess the variety and frequency of foods consumed by autism, as well as the appropriateness of this consumption and to evaluate the changes of creatine metabolism, developing preliminary tests to determine the most appropriate conditions for the identification and possible quantification of opioid peptides derived from gluten and casein by HPLC. To achieve these objectives was drawn up a nutritional interview containing questions on sociodemographic characteristics of the families of autistic participants, personal history of disease, autistic behavior during meals, and a survey of eating habits. To characterize the clinical status of the population a psychological evaluation was performed using a quantitative Childhood Autism Rating Scale (CARS). The creatinine concentrations in urine of autistic and control group formed by relatives of the same sex was determined by the Jaffé. The results on the characterization of the population indicated that one third of parents of autistic children have lower education and 60% of family income in the range from 2 to 4 minimum wages. According to the method of evaluation CARS 64% of autistic children are severe cases. The allergic rhinitis is the most prevalent disease in this population. On average 60.71% of people with autism have gastric symptoms, the most frequent flatulence (39.90%). The record on eating behavior found that 50% of autistic children express the behavior of eating too fast, and 46.43% consume excessive portions of food. This fact directly influences the food habits. The assessment of adequacy of nutrient intake have revealed that 57.14% of energy consumption and lower than the recommended intake of fiber, and calcium acid ascorbic. The analysis revealed that creatinine concentration values are significantly lower in autistic children and the control group formed by distant relatives and are compared with similar group formed by his parents. Initial analysis by high performance liquid chromatography showed that the two methods developed and coded as number 2 is more efficient than a number, for it can distinguish the peaks of all patterns of peptides tested and that the initial protocol for the extraction of opioid peptides in the solid phase should be reviewed.
343

Sorpce PCP na lignitu / PCP sorption of lignite

Šnédarová, Gabriela January 2008 (has links)
Within the framework of this diploma thesis, the sorptive capability of a lignite as a natural adsorbent was applied on an aqueous solution of pentachlorophenol. The aqueous solution of this substance, which is very dangerous for the environment, was prepared in various concentration ranges according to reached solubility. The solubility is noticed in different literatures variously and then is not applicable. That is why it was necessary to find out the ”real“ solubility. The aqueous solution of pentachlorophenol of given concentration was subsequently put to adsorption with exactly defined quantity of the lignite and as a result the adsorptive isotherms were obtained. These isotherms represent the adsorption capability in dependence on the adsorption duration, quantity of used lignite and concentration of pentachlorophenol solution. By the adsorption with duration longer than one hour, the quantity of adsorbed PCP does not increase markedly.
344

Analýza nápojů slazených extrakty stévie cukerné / Analysis of drinks sweetened with stevia extracts

Procházka, Václav January 2013 (has links)
The steviolglycosides are the natural, sweet substances from Stevia rebaudiana Bertoni. It affect human health positively and its sweetness is 300x stronger than the sweetness of sucrose. That's why it's used to sweetening the commercial products. Because of its potential properties it's good to have an appropriate method to isolate it. High performance liquid chromatography ( HPLC) is based on the separation of analyte between two immiscible phases with high pressure pump and appropriately chosen stationary phase in the column. Than the analytes come out from the column in different retention times. This master´s thesis follows up selection of the best HPLC system for isolation of the main steviolglycosides and its analysis in commercial products. In the theoretical part of the thesis is described the origin, basic characteristics, botanical description, cultivation and affect to the human health of Stevia rebaudiana Bertoni and its use in food industry. There are also concisely characterized the sweet substances contained in the plant, so called steviolglycosides. Than there are given the theoretical basics of high performance liquid chromatography, HPLC instrumentation and its specific applications at sleviolglycosides with the basic chromatographic parameters. The object of the first experimental part was to research the optimum conditions for time and separation effective chromatographic analysis and select the best chromatographic system for isolation of steviolglycosides. In the second experimental part, I have compared and defined the main steviolglycosides (stevioside, rebaudioside A) in nine selected products, commercially available in Czech republic, with the best chromatographic method. In these products was the contain of the stevioside or rebaudioside A confirmed or refused.
345

Dicroísmo circular vibracional e eletrônico na determinação da configuração absoluta de benzopiranos de Peperomia obtusifolia e Piper gaudichaudianum (Piperaceae) : implicações biológicas e biossintéticas /

Batista Junior, João Marcos. January 2012 (has links)
Resumo: Estudos fitoquímicos visando o isolamento de benzopiranos quirais foram realizados em Peperomia obtusifolia e Piper gaudichaudianum (Piperaceae). Da espécie P. obtusifolia foram isolados dois cromanos racêmicos, a peperobtusina A e o ácido 3,4-diidro-5-hidróxi-2,7-dimetil-8-(3-metil-2-butenil)-2-(4-metil-1,3-pentadienil)-2H-1- benzopirano carboxílico, bem como oito ésteres isoméricos deste último com os monoterpenos borneol e fenchol, inéditos na literatura. P. gaudichaudianum forneceu o cromeno ácido gaudichaudiânico, também como racemato. As misturas estereoisoméricas foram resolvidas por meio de cromatografia líquida de alta eficiência quiral e os estereoisômeros purificados tiveram sua configuração absoluta determinada por comparação dos espectros experimentais de dicroísmo circular vibracional e eletrônico com aqueles preditos por cálculos mecânico-quânticos ab initio. Peperobtusina A e o ácido 3,4-diidro-5-hidróxi-2,7-dimetil-8-(3-metil-2-butenil)- 2-(4-metil-1,3-pentadienil)-2H-1-benzopirano carboxílico foram assinalados como (+)-R, enquanto o ácido gaudichaudiânico foi assinalado como (+)-S. Os ésteres de cromano com borneol foram assinalados como (−)-2S,1′′′S,2′′′R,4′′′S e (+)- 2R,1′′′S,2′′′R,4′′′S, enquanto os ésteres com fenchol foram assinalados como (−)- 2S,1′′′R,2′′′R,4′′′S e (+)-2R,1′′′R,2′′′R,4′′′S. Com a configuração absoluta assegurada, foi possível a verificação do potencial tripanocida seletivo e sinérgico para os enantiômeros do ácido gaudichaudiânico e inibidor de HIV-1 protease seletivo para o (−)-(S)-ácido 3,4-diidro-5-hidróxi-2,7-dimetil-8-(3-metil-2-butenil)-2-(4- metil-1,3-pentadienil)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Phytochemical investigations focused on chiral benzopyrans were carried out on Peperomia obtusifolia and Piper gaudichaudianum (Piperaceae). Two racemic chromanes, peperobtusin A and 3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3-methyl-2- butenyl)-2-(4-methyl-1,3-pentadienyl)-2H-1-benzopyran carboxylic acid, as well as eight novel isomeric esters of the latter with the monoterpenes borneol and fenchol, were isolated from P. obtusifolia. P. gaudichaudianum afforded the racemic chromene gaudichaudianic acid. All stereoisomeric mixtures were resolved using chiral high performance liquid chromatography and the purified compounds had their absolute configuration determined by comparison of experimental vibrational and electronic circular dichroism spectra with those calculated using ab initio quantummechanical methods. Peperobtusin A and 3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3- methyl-2-butenyl)-2-(4-methyl-1,3-pentadienyl)-2H-1-benzopyran carboxylic acid were assigned as (+)-R, whereas gaudichaudianic acid was assigned as (+)-S. The borneol chromane esters were assigned as (−)-2S,1′′′S,2′′′R,4′′′S and (+)- 2R,1′′′S,2′′′R,4′′′S, while the fenchol esters were assigned as (−)-2S,1′′′R,2′′′R,4′′′S e (+)-2R,1′′′R,2′′′R,4′′′S. Once the absolute configuration had been established it was possible to identify a selective and synergistic trypanocidal activity for the enantiomers of gaudichaudianic acid as well as a selective HIV-1 protease inhibitory potential for (−)-(S)-3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3-methyl-2-butenyl)-2-(4- methyl-1,3-pentadienyl)... (Complete abstract click electronic access below) / Orientador: Maysa Furlan / Coorientador: Silvia Noelí López / Banca: Alberto José Cavalheiro / Banca: André Luiz Meleiro Porto / Banca: Maria Fátima das Graças Fernandes da Silva / Banca: Angelo da Cunha Pinto / Doutor
346

Molekulargenetische Diagnostik des ATRX-Syndroms mittels Denaturing High-Performance Liquid Chromatography (DHPLC)

Junge, Cornelia 26 May 2014 (has links)
Die DNA-Sequenzierung nimmt in der molekulargenetischen Diagnostik seit vielen Jahren einen großen Stellenwert ein. Zeit- und kosteneffektivere Methoden wie die DHPLC wurden seither für verschiedene Gene etabliert. Ziel dieser Arbeit war die Etablierung der DHPLC für das ATRX-Gen bei Patienten mit Verdacht auf das ATRX-Syndrom. Nach erfolgreicher Etablierung der DHPLC sollten im Rahmen dieser Arbeit 38 Patientenproben des Instituts für Humangenetik der Universität Leipzig mit Verdacht auf das ATRX-Syndrom mittels DHPLC und Sequenzierung untersucht werden. Die Etablierung der DHPLC gelang in der vorliegenden Arbeit für alle - das ATRX-Gen vollständig umspannenden - 42 Fragmente. Jede der vorliegenden Sequenzvariationen konnte nach Abschluss der Arbeit detektiert werden. Unter Verwendung von Maxima® stellten sich initial 22 von 24 verschiedenen Sequenzvariationen zum Wildtyp different dar. Die verbleibenden zwei Mutationen p.R246C und p.A238P im Fragment 9 wurden unter Verwendung höherer Temperaturen, eines kürzeren Fragmentes oder anderer Polymeraseenzyme (AmpliTaq Gold® bzw. HighFidelity) detektiert. Nach Abschluss der Etablierung der DHPLC konnte eine Sensitivität und Spezifität von 100% erreicht werden. In den Patientenuntersuchungen des Instituts für Humangenetik der Universität Leipzig fanden sich bei 38 Patientenproben vier verschiedene als benigne beschriebene Polymorphismen bei insgesamt 19 Patienten, ein noch nicht veröffentlichter Polymorphismus im Intron 26 sowie eine bis dato nicht beschriebene und als pathogen einzustufende Mutation im Exon 34. In 100 Kontrollen der DNA-Bank des Instituts für Humangenetik der Universität Leipzig konnte der bisher nicht publizierte Polymorphismus im Intron 26 sieben Mal gefunden werden. Die bis dato nicht beschriebene Deletion p.2385_2395del im Exon 34 führt zu einem vorzeitigen Abbruch des ATRX-Proteins und ist somit als sicher pathogen einzustufen. Die Untersuchung der Mutter des Patienten konnte den Konduktorenstatus nachweisen. Für die Familie des betroffenen Patienten konnte mit der vorliegenden Arbeit die Diagnose des ATRX-Syndroms gesichert werden. Die DNA-Proben der Patienten bei denen keine Mutation nachgewiesen werden konnte, sollten bei weiterhin dringendem Verdacht auf das ATRX-Syndrom mittels qRT-PCR bzw. MLPA untersucht werden, um große Deletionen, Insertionen oder Duplikationen auszuschließen. Mithilfe dieser Arbeit gelang die Etablierung der DHPLC für das ATRX-Gen als ökonomische, sehr sensitive und effiziente Methode zur Diagnostik des ATRX-Syndroms. Die Entscheidung, in welcher Form und mit welcher Methode DNA-Proben bei Verdacht auf ATRX-Syndrom untersucht werden, bleibt jedoch eine individuelle Entscheidung jedes Instituts unter Betrachtung der jeweiligen Gegebenheiten vor Ort.
347

Stanovení polyaromatických uhlovodíků v pevných matricích hydrosféry metodou QuEChERS - porovnání se stávajícími metodami / Determination of polycyclic aromatic hydrocarbons in hydrosphere solid matrices by QuWChERS - comparision with present methods

Sudová, Petra January 2012 (has links)
Thesis are aimed to the optimization and validation of the QuEChERS method for determination of polycyclic aromatic hydrocarbons in solid matrices of hydrosphere. The QuEChERS method was also used for determination of polycyclic aromatic hydrocarbons in real samples and for comparison of measured results, time and material costs of the method with currently employed methods: (1) accelerated solvent extraction connected with gel permeation chromatography (ASE/GPC), and (2) ultrasonic extraction connected with solid phase extraction (UZ/SPE). According to the validation criteria, the QuEChERS method is suitable for the determination of polycyclic aromatic hydrocarbons in solid matrices of hydrosphere. The QuEChERS technique provides comparable results to ASE/GPC and UZ/SPE. In terms of price and time for sample preparation, the QuEChERS method allows (unlike the methods ASE/GPC and UZ/SPE) fast and inexpensive determination of polycyclic aromatic hydrocarbons in solid samples of hydrosphere.
348

Studium kinetiky trypsinového štěpení peptidů a chirálních separací biologicky aktivních látek metodou HPLC / Study of peptide digestion kinetics by trypsin and chiral separations of biologically active compounds by HPLC

Šlechtová, Tereza January 2016 (has links)
This dissertation thesis composes of two parts; the first part focus on the characterization of trypsin, enzyme frequently used in proteomic research for the investigation and identification of protein sequences, and its peptide digestion kinetics. The second part is aimed to the enantioseparations of biologically active compounds. First part of this project focus on tryptic digestion of synthetic peptides and the development of HPLC method for the identification of synthetic peptides and their fragments. Using the in-solution digestion and HPLC method, relative kinetic constants were determined for problematic sequences. Amino acids responsible for the decrease in trypsin catalytic activity and their location towards the cleavage site were studied. Certain slight exopeptidase activity of trypsin was noted, especially at the end of peptide chain. Furthermore, three columns with immobilized trypsin used in HPLC were compared concerning their catalytic activity. The immobilization of enzymes on solid support is used to elevate the amount of enzyme present during digestion and to assure better repeatability and reproducibility of obtained results. Activity of a new trypsin column synthesized at the University of North Carolina at Chapel Hill was compared to two commercially available trypsin columns....
349

A comparative study of Tosoh G11 and Bio-Rad D-100 analyzers for HbA1c analysis / En jämförande studie av Tosoh G11 och Bio-Rad D-100 för HbA1c -analys

Alvin, Maja, Lundin, Filippa January 2023 (has links)
Diabetes mellitus is one of the most common diseases worldwide. The continued prevalence increase, together with the complexity of the disease with severe long-term complications makes efficient diagnostical and monitorial methods very important. The determination of glycated hemoglobin, HbA1c, plays an important role in both, underlying the importance of high-quality analytical instruments. Whenever a new instrument is introduced into routine clinical use an evaluation is needed. This study evaluated the agreement between the new Tosoh G11 HbA1c high performance liquid chromatography system as a replacement for the Bio-Rad D-100 at the Chromatographic Department of the Institute of Laboratory Medicine, Faculty of Medicine, University of Debrecen. In total, 66 samples were analyzed using both analyzers and a Bland-Altman comparison was performed together with a correlation study. Additionally, a linearity check, optimal error and routine error testing was carried out specifically for the Tosoh G11. The results showed high agreement between measurements, r=0.9975 (p<0.001) for HbA1c mmol/mol and r=0.9971 (p<0.001) for HbA1c %. High repeatability and accuracy were observed of the Tosoh G11 with the highest variation coefficient of 1.50 % and linearity r =0.9999. The conducted study supports the replacement of the Bio-Rad D-100 to the Tosoh G11. / Diabetes mellitus är en av de vanligaste världsomfattande sjukdomarna. Fortsatt prevalensökning, tillsammans med den komplexa sjukdomsbilden innefattande allvarliga långsiktiga komplikationer gör effektiva diagnostiska och övervakande metoder väldigt viktiga. Bestämning av glykerat hemoglobin, HbA1c, spelar en viktig roll i båda, vilket kräver att analysinstrument av hög kvalitet finns. När ett nytt instrument introduceras inom kliniska rutinanalyser krävs utvärdering. Denna studie utvärderade överrensstämmelsen mellan det nya Tosoh G11 HbA1c högupplösande vätskekromatografisystemet som en ersättning för Bio-Rad D-100 på den kromatografiska enheten av laboratoriemedicin på Debrecens universitet. Totalt analyserades 66 prov med respektive instrument och Bland-Altman jämförelse genomfördes tillsammans med en korrelationsstudie. Dessutom utfördes ett linjäritetstest, optimal- och rutinfeltest specifikt för Tosoh G11. Resultaten visade en hög överrensstämmelse mellan mätningarna, r=9975 (p<0.001) för HbA1c mmol/mol och r =9971 (p<0.001) för HbA1c %. Tosoh G11 visade hög repeterbarhet och noggrannhet, med den högsta variationskoefficient på endast 1.50 % och en linjäritet på r=0.9999. Den genomförda studien stödjer Tosoh G11 som ersättning för Bio-Rad D-100.
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Survey of Flavonoids and Their Distribution in Different Kinds of Onions Using High Performance Liquid Chromatography and Gas Chromatography Mass Spectrometry.

Racharla, Archana 17 December 2011 (has links) (PDF)
This research is done to determine the distribution of flavonoids in diverse varieties of onions (commercial and wild onions). Reflux extraction method was done on dried onions and the abstracts were analyzed subsequently by high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GCMS). Statistical calculations were done to see if there are significant differences in the varieties of onions studied from the chromatographic profiles obtained. The chromatograms obtained were patterned using visual observations, scatter plot study, correlation co-efficient, and ANOVA to evaluate the significant difference of the distribution of flavonoids in varieties of onions. The organic white onions seem to have closer flavonoids profile to that of natural wild onions with a corelation coefficient of 0.99 from HPLC data and 0.88 from the GCMS data. The ANOVA results also support these conclusions. However, natural wild onions tend to have more constituents that can be beneficial.

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