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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.
21

Fluorescence Spectroscopy Prediction of Fish Freshness / 蛍光分光による魚の鮮度予測

Liao, Qiuhong 24 November 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20768号 / 農博第2251号 / 新制||農||1054(附属図書館) / 学位論文||H29||N5088(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 近藤 直, 教授 清水 浩, 教授 飯田 訓久 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
22

The prevalence and characteristics of hypouricemia: a descriptive study of medical check-up and administrative claims data / 低尿酸血症の有病割合とその特徴:レセプトおよび健康診断データを用いた記述疫学研究

Koto, Ruriko 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(社会健康医学) / 甲第24537号 / 社医博第129号 / 新制||社医||12(附属図書館) / 京都大学大学院医学研究科社会健康医学系専攻 / (主査)教授 中山 健夫, 教授 近藤 尚己, 教授 山本 洋介 / 学位規則第4条第1項該当 / Doctor of Public Health / Kyoto University / DFAM
23

Purine Nucleoside Mediated Neuroprotection in the 6-Hydroxydopamine Rodent Model of Parkinson's Disease

Terpstra, Brian T. 20 April 2011 (has links)
No description available.
24

The Unexpected Role of Uric Acid in Lifecycle Synchronicity and Symbiosis

Menzies, Jessica 07 1900 (has links)
Functionality of Cnidarian symbiosis with Symbiodiniaceae is fundamental to reef ecosystem success. Symbiodiniaceae cells have a complex life history, which, in hospite, is controlled by the host. In addition to the endosymbiotic lifestyle, they can exist free-living cells which diurnally alternate between a coccoid, vegetative night-time form to a day-time motile, flagellated cell. Their cell division cycle is gated by external light cues, and correlates with transitions in cell morphology. In contrast, endosymbiotic cells have an elongated G1 phase – demonstrating a de-coupling of cell cycle from 24-hour cycle in response to symbiosis. Furthermore, daughters of dividing endosymbiotic Symbiodiniaceae remain as coccoid cells, de-coupling morphological and cell division cycles. How this occurs remains unknown. The answer may lie in crystalline uric acid deposits, which are present only in motile, daytime cells, correlating with G1 and S phase. These store excess nitrogen and are quickly metabolized in low nitrogen availability. They also function as an eyespot. The influence of uric acid on the life cycle of free-living and endosymbiotic Symbiodiniaceae is unknown. In this study, I treated cultures of B. minutum with allopurinol, an inhibitor of uric acid synthesis. Flow cytometry showed that allopurinol the reduced growth rate and ratio of coccoid:motile cell cultures. RNA sequencing and differential gene expression analysis identified biological processes enriched in allopurinol treatment. I hypothesize that an intracellular lack of nitrogen imposed lack of uric acid crystals stimulates the General Amino Acid Control pathway. This represses translation, explaining the downregulation of ribosomal proteins, and upregulates amino acid and purine de novo biosynthesis pathways. Repression of translation may slow cellular growth and the G1 phase of the cell cycle, reducing number of cells meeting the size threshold for G1/S transition. Without uric acid deposits, cells may lack a functioning eyespot and not receive light cues which usually trigger morphological transitioning. This may suppress the motile morphology of free-living Symbiodiniaceae and cells in hospite even though the cell division cycle progresses, albeit more slowly. Genes involved in biosynthesis of flagella, thecal plates and the eyespot are upregulated, suggesting suppression of the motile form may act downstream of transcription.
25

High performance liquid chromatographic determination of uric acid in grains and cereal products as a measure of insect infestation

Wehling, Randy Lee. January 1980 (has links)
Call number: LD2668 .T4 1980 W44 / Master of Science
26

Aplicações analíticas de eletrodos quimicamente modificados por espécies de interesse biológico / Analytical applications of chemically modified electrode of biological species interest

Silva, Robson Pinho da 14 September 2007 (has links)
O trabalho apresentado nesta Dissertação de Mestrado descreve o desenvolvimento e aplicação de eletrodos de pasta de carbono modificados eletroquimicamente em soluções de guanina e de eletrodos de grafite pirolítico modificados em soluções de dopamina. Estes eletrodos foram empregados na detecção e, a quantificação, por voltametria de pulso diferencial (VPD), de alguns compostos de importância biológicas tais como NADH, NADPH, 8-oxo-guanina, ácido úrico (AU), ácido ascórbico (AA), dopamina (DA) e xantina (XA). No primeiro caso, os eletrodos de pasta de carbono foram modificados em solução de guanina por aplicação de um potencial de 1,1 V (vs Ag/AgCl, KClsat) ao eletrodo de trabalho por 12 minutos sob sat agitação constante. Com estes eletrodos detectaram-se NADH, NADPH, 8-oxo-guanina e AU, com limites de detecção de 3,3, 3,7, 2,0 e 6,6 x 10-6 mol L-1 respectivamente, na faixa de concentração de 7,5 x 10-6 a 8,1 x 10-4 mol L-1 . No segundo caso, eletrodos de grafite pirolítico, previamente tratados em solução de NaOH, foram modificados eletroquimicamente em solução de DA por aplicação de um potencial 1,5 V (vs Ag/AgCl, KClsat ) ao eletrodo de trabalho durante 2 minutos. Com estes eletrodos foi possível a determinação simultânea de AA, AU e DA. Para obtenção das curvas analíticas variou- se a concentração do analito de interesse, mantendo-se constante a concentração dos possíveis interferentes nos valores de 1,0 x 10-4 mol L-1 (DA), 5,0 x 10-5 mol L-1 (AU) e 1,0 x 10-3 mol L-1 (AA). Os limites de detecção calculados para AU, AA e DA foram respectivamente de 1,4 x 10-6 mol l-1 , 2,5 x 10-5 mol l-1 e 1,1 x 10-7 mol l-1 . Ácido úrico foi determinado em amostras de urina, sangue e soro humano com 92 a 103 % de recuperação, sem a necessidade de tratamento prévio das amostras. / Chemically Modified Carbon Paste and Pyrolitic Graphite Electrodes were prepared via electrochemical deposition from guanine and dopamine solutions. Carbon paste electrodes were modified in guanine solutions under an applied potential of 1.1 V (vs Ag/AgCl, KClsat ) during 12 minutes under constant stirring. They were used for sat electrochemical detection of NADH, NADPH, uric acid and 8-oxoguanine. Detection limits were 3.3, 3.7, 6.6 and 2.0 10-6 mol L-1 respectively, with sensitivity of 0.13, 0.10, 0.26 and 0.40 A mol-1 L cm-2 , respectively. The electrodes showed high reproducibility and absence of surface poisoning effects. Good analytical performance was attributed to the formation of superficial dimer or trimers species of guanine during the modification process. Pyrolitic graphite electrodes, previously submitted an electrochemical treatment in NaOH solution, were modified in dopamine solution (phosphate buffer, pH 10) under an applied potential of 1.5 V (vs Ag/AgCl, KClsat ) during 2 minutes under constant sat stirring and, further used for the simultaneous determination of ascorbic acid (AA), uric acid (AU) and dopamine (DA). The analytical curves were obtained changing the concentration of the wished analyte, at constant concentration levels of the interferences: 1.0 x 10-4 mol L-1 (DA), 5.0 x 10-5 mol L-1 (UA) and 1.0 x 10-3 mol L-1 (AA). Detection limits were 1.4 x 10-6 mol L-1 , 2.5 x 10-5 mol L-1 and 1.1 x 10-7 mol L-1 for UA, AA and DA, respectively. Uric acid was determined in human urine, blood and serum samples without any previous treatment. Recovering percentages of 92 to 103 % were obtained.
27

Desenvolvimento de procedimento analítico em fluxo com multicomutação para a determinação espectofotométrica de ácido úrico em urina / Development of a multicommuted flow-based analytical procedure for the spectrophotometric determination of uric acid in urine

Rocha, Diogo Librandi da 04 September 2009 (has links)
A mecanização de procedimentos analíticos em análises clínicas traz vantagens tais como minimização de erros sistemáticos e do tempo das análises. Sistemas de análises em fluxo com multicomutação apresentam grandes potencialidades nesse sentido, atendendo às necessidades da mecanização de procedimentos analíticos de maneira versátil e robusta. Estes sistemas permitem minimizar o consumo de reagentes e a geração de resíduos, devido ao gerenciamento preciso de pequenos volumes de soluções por dispositivos controlados eletronicamente, tais como microbombas solenoide. O fluxo pulsado proporcionado pelas microbombas e a estratégia da amostragem binária melhoram a mistura entre amostra e reagentes. O ácido úrico é o principal produto final do metabolismo de purinas. A determinação deste analito em amostras de urina apresenta importância clínica, uma vez que sua concentração pode auxiliar no diagnóstico de disfunções no organismo humano, como a gota e o mau funcionamento dos rins. Um procedimento analítico empregando sistema de análises em fluxo com microbombas solenoide foi desenvolvido para a determinação de ácido úrico em amostras de urina. Os íons Cu(II) são reduzidos pelo ácido úrico a íons Cu(I), que podem ser quantificados por espectrofotometria na presença do ácido 4,4\'-dicarboxi-2,2\'- biquinolínico (BQA). Resposta linear foi observada entre 10 e 100 µmol L-1 de ácido úrico, sendo a curva analítica representada pela equação A=(0,0063±0,0002)CAU + (0,0285±0,0040), r = 0,999, em que CAU é a concentração de ácido úrico em µmol L-1. O limite de detecção foi estimado em 3,0 µmol L-1 (99,7% de nível de confiança; n = 20). O coeficiente de variação foi estimado em 1,2% com 20 medidas de uma solução de ácido úrico 75 µmol L-1 e a frequência de amostragem foi de 150 h-1. As principais espécies concomitantes presentes na urina não interferem na determinação de ácido úrico em concentrações até 5 vezes maiores que as usualmente encontradas. Recuperações entre 91 e 112% foram estimadas e os resultados das análises de 4 amostras de urina concordaram com os obtidos pelo procedimento enzimático para a determinação de ácido úrico (95% de nível de confiança). O alto grau de diluição da amostra necessário (100 vezes) minimiza o volume de amostra utilizado e os efeitos de matriz. Uma simples reconfiguração do sistema e a reotimização das frações volumétricas permitiram que a amostra fosse diluída em linha por reamostragem na zona dispersa. Resposta linear foi observada até 5,0 mmol L-1 de ácido úrico, sendo a curva analítica obtida representada pela equação A=(0,105±0,001) CAU + (0,023±0,003), r=0,999, em que CAU é a concentração de ácido úrico em mmol L-1. O coeficiente de variação, o limite de detecção e a frequência de amostragem foram estimados em 1,0%, 0,2 mmol L-1 e 95 h-1, respectivamente. Os resultados da análise de 3 amostras de urina concordaram com os obtidos pelo procedimento enzimático, com nível de confiança de 95% / Mechanization of analytical procedures in clinical analysis brings advantages such as minimization of systematic errors and analysis time. Multicommuted flow systems attain the requirements to mechanization of analytical procedures in a versatile and robust way, minimizing reagent consumption and waste generation, due to the low solution volumes handled by electronically controlled devices, such as solenoid micro-pumps. The pulsed flow characteristic of the micro-pumps and the binary sampling approach improve sample and reagent mixing. Uric acid is the main end product of purine metabolism and its determination in urine shows clinical importance, because its concentration can be related to human organism dysfunctions, such as gout and renal disorders. An analytical procedure employing a flow system with solenoid micro-pumps was developed, aiming the determination of uric acid in urine samples. Cu(II) ions are reduced by uric acid to Cu(I) ions that can be quantified by spectrophotometry in the presence of 2,2´-biquinoline 4,4´-dicarboxylic acid (BCA). Linear analytical response was observed between 10 and 100 µmol L-1 uric acid and the analytical curve corresponds to the equation A=(0.0063±0.0002) CUA + (0.0285±0.0040), r = 0.999, in which CUA is the uric acid concentration in µmol L-1. The detection limit was estimated as 3.0 µmol L-1 (99.7% confidence level; n = 20). The coefficient of variation was estimated in 1.2% with 20 replicates of a 75 µmol L-1 uric acid solution and sampling rate of 150 h-1 was achieved. The main concomitant species does not interfere in uric acid determination in concentrations up to 5-fold higher than that usually found in urine samples. Recoveries from 91 to 112% were estimated and the results for 4 urine samples agreed with those obtained by the commercially available enzymatic kit for determination of uric acid (95% confidence level). The 100-fold sample dilution minimizes sample consumption and matrix effects. A simple system reconfiguration and a re-optimization of volumetric fractions attained on-line sample dilution by zone sampling. Linear response was observed up to 5.0 mmol L-1 uric acid and the analytical curve corresponds to the equation A=(0.105±0.001) CUA\' + (0.023±0.003), r = 0.999, in which CUA\' is the uric acid concentration in mmol L-1. The coefficient of variation, detection limit and sampling frequency were estimated as 1.0%, 0.2 mmol L-1 and 95 h-1, respectively. The results of the analysis of 3 urine samples also agreed with those obtained with the enzymatic procedure at the 95% confidence level
28

Selective Determination of Uric Acid in the Presence of Ascorbic Acid at Screen-Printed Carbon Electrode Modified with Electrochemically Pretreated Carbon Nanotube

Lin, Liang-Shian 02 September 2010 (has links)
none
29

The association of uric acid and plasminogen activator inhibitor-1 (PAI-1) with cardiovascular function in South African women : the POWIRS-study / I.M. Palmer

Palmer, Iolanthe Marike January 2006 (has links)
Motivation: Hypertension is a fast growing health risk, leading to increased incidences of cardiovascular dysfunction and mortality. However, the prevalence of hypertension is higher in some ethnic populations than others. Several South African studies have found that the African population is more susceptible to the development of hypertension, compared to the Caucasian population. Cardiovascular dysfunction is often accompanied by elevated levels of uric acid (UA) and plasminogen activator inhibitor-I (PAI-1) and both are factors associated with the metabolic syndrome. A lack of data regarding the association of UA and PAL1 with cardiovascular dysfunction in a South African context, serves as a motivation for conducting this study. Objective: To determine the association of UA and PAI-1 with cardiovascular dysfunction in African and Caucasian women from South Africa. Methodology: The manuscript presented in Chapter 2 made use of the data obtained in the POWIRS (Profiles of Obese Women with the Insulin Resistance Syndrome) study. A group of 102 African women and 115 Caucasian women, living in the North West Province of South Africa, were recruited according to their body mass indexes. The groups were divided into lean, overweight and obese according to their body mass index. Anthropometric and cardiovascular measurements were taken and determinations were done of their blood lipid profiles, UA. PAI-1, fasting insulin and glucose levels, HOMA-IR (homeostasis model assessment-insulin resistance) and leptin levels. The subject's total dietary protein intake was determined by means of a dietary questionnaire. Comparisons between the groups were done using an independent t-test as well as a multiple analysis of covariance (MANCOVA) whilst adjusting for certain variables. Each ethnic group was divided into UA and PAI-1 tertiles, for comparison between the 1" and 3' tertiles. Correlation ~0efIi~ientS were determined to show any associations between UA and PAI-1 with cardiovascular variables as well as variables associated with the metabolic syndrome. Forward stepwise multiple regression analyses were performed using UA and PAL1 respectively as dependent variables. The study was approved by the Ethics committee of the North-West University and all the subjects gave informed consent in writing. The reader is referred to the experimental procedure section in Chapter 2 for a more detailed description of the subjects, study design and analytical procedures used in this dissertation. Results and conclusion: Results from the POWIRS-study showed that despite the African women's higher blood pressure, they had significantly lower levels of UA and PAI-I compared to the Caucasian women. Although the Caucasian women had significantly higher circulating levels of UA and PAI-1, they showed no sign of cardiovascular dysfunction. The detrimental effects might, however, become more noticeable with an increase in age. From this study it is concluded that UA and PAL1 is not associated with the increased blood pressure in young African women. / Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2006.
30

Inkstų funkcinių rodiklių kitimai fizinio krūvio metu / The effect of physical exercise on renal function parameters

Michailovienė, Jolanta 16 August 2007 (has links)
Žmogaus organizmas normaliai gali egzistuoti tik tada, kai yra palaikoma pastovi vidinė organizmo terpė – homeostazė. Ji priklauso nuo normalios daugelio sistemų ir organų tarp jų ir inkstų veiklos. Šiuo tyrimu siekėme palyginti fizinio krūvio sukeltus inkstų funkcinius kitimus su sergančiųjų arterine hipertenzija patologiniais inkstų funkciniais pakitimais. Šio darbo tikslas – ištirti sportuojančių, nesportuojančių bei sergančiųjų pirmine arterine hipertenzija tiriamųjų kraujo biocheminių rodiklių, nusakančių inkstų funkciją, kaitą fizinio krūvio metu. Nurodytam tikslui pasiekti iškelti sekantys uždaviniai: 1. Palyginti sportuojančių, nesportuojančių bei sergančiųjų pirmine arterine hipertenzija kūno dydžio rodiklius. 2. Atlikti sportuojančių, nesportuojančių bei sergančiųjų pirmine arterine hipertenzija tiriamųjų kraujo biocheminių rodiklių, nusakančių inkstų funkciją, analizę ramybėje. 3. Nustatyti sportuojančių ir nesportuojančių tiriamųjų inkstų funkcinius rodiklius po fizinio krūvio ir palyginti su sergančiųjų pirmine arterine hipertenzija ramybės reikšmėmis. 4. Palyginti sportuojančių ir nesportuojančių tiriamųjų inkstų funkcinių rodiklių vidurkių tarp ramybės ir po fizinio krūvio skirtumus. 5. Išnagrinėti kreatinino klirenso kitimus. Šiame darbe kėlėme hipotezę, kad sportuojančių tiriamųjų inkstų funkciniai rodikliai po fizinio krūvio padidės labiau nei nesportuojančių tiriamųjų ir bus artimi sergančiųjų arterine hipertenzija rodikliams. Tyrime savo noru dalyvavo 10... [toliau žr. visą tekstą] / In the literature, there exists numerous studies of exercise – induced sports hematuria, proteinuria, acute renal failure following a marathon (Poortmans et al., 2001; Ayca et al., 2006; Steward, Pasen, 1980). But studies investigating the effects of exercise on blood indicators of renal function are quiet few. The aim of this study was to investigate the effects of submaximal veloergometric exercise on very important biochemical indicators of renal function – level nitrogen compounds in the blood. In venous blood samples was investigate concentrations of creatinine, urea, total protein and uric acid before and after submaximal (about 50 % VO2max) veloergometric exercise. This nitrogen compounds was studies in three groups of subjects. Methods. The study was performed on 10 trained (1 group), 10 untrained (2 group) and 10 subjects with I° hypertensive status (3 group). The age range was 20,5-21,3 yr, weight – 71,8-77,3 kg, height – 177-180 cm. All subjects volunteered to participate in the study after providing written informed consent. The study was approved in accordance with the Declaration of Helsinki. Blood samples were collected before and after the submaximal veloergometric test into vacationer tubes. Concentrations of creatinine, urea, total protein and uric acid in the serum were determined using Technician Auto Analyzer ADVIA 1650 system. Data from Submaximal ride compared using two-way repeated – measures ANOVA. Dependent t-tests were administered in the event of... [to full text]

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