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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.
381

Renal blood flow and the pathophysiology of acute kidney injury

Prowle, John Richard January 2013 (has links)
No description available.
382

Applications of mass spectrometry in clinical chemistry and biomedical research

Aguiar, Mike. January 2007 (has links)
Note: / Clinical chemistry is a medical discipline whose aim is to diagnose and assess disease by analysis of biological specimens. Modem laboratories can perform several hundred different tests using many different methods developed over the last century. The classical, more traditional assays are typically labour-intensive, not multiplexed (only measure one analyte or disorder per assay), expensive, require a long turnaround time, and may not provide adequate sensitivity and specificity. Developments in mass spectrometry (MS) and related technologies over the last two decades have provided solutions for many if not all of these shortcomings. While MS based applications have not yet been widely implemented in clinical chemistry laboratories, current developments will encourage the replacement of traditional methods as well as the expansion of clinically diagnostic endpoints. Indeed, modem MS can be used to simultaneously analyze and quantitate multiple biomarkers in a single analysis. Currently, no other technique exists that can provide a comparable multiplexed analysis. In this thesis, current MS and related technologies were developed and applied to several important but distinct clinical chemistry applications. [...] / La chimie clinique est une discipline medicale qui a pour but de diagnostiquer la presence et la progression d'une maladie par l'analyse d'echantillons biologiques. Les laboratoires modemes peuvent executer des centaines d'analyses en utilisant plusieurs methodes developpees au courrant des cent demieres annees. Les essaisc1assiques, et plus traditionnels, sont souvent laborieux, non multiplexe (mesurent seulement un analyte par essai), cher, exige un long temps de rotation et risque de ne pas fournir une specificite adequate. Pendant les deux dernieres decennies, les developpements dans Ie domaine de la spectrometrie de masse (MS) et les technologies rattachees ont foumi des solutions a plusieurs, pour ne pas dire tous, manques retrouves dans les methodes d'analyse traditionnelles.
383

Identification of a transducin (beta)-like 3 protein as a potential biomarker of prediabetes from rat urine using proteomics

Mofokeng, Henrietta Refiloe January 2010 (has links)
<p>Obesity is a globally increasing disease particularly in developing countries and among children. It is mainly caused by intake of diets high in fat and the lack of physical activity. Obesity is a risk factor for diseases such as type II diabetes, high blood pressure, high cholesterol and certain cancers. Prediabetes is a condition where blood glucose levels are above normal but have not&nbsp / reached those of diabetes. It is difficult to diagnose, as there are no signs or symptoms. Some type II diabetes patients bear no symptoms at all and the disease is discovered late. Proteomics is a field that can provide opportunities for early diagnosis of diseases through biomarker discovery. The early diagnosis of diabetes can assist in the prevention and treatment of diabetes. Therefore there is a need for the early diagnosis of diabetes. Twenty Wistar rats were used. The rats were initially fed a CHOW diet, which is the standard balanced diet for rats, for 4 weeks. The rats were then divided into 2 groups of 10 where 1 group was fed CHOW and another was fed a high fat (HF) diet in order to induce obesity. The two groups were fed their respective diets for 18 weeks. Rats were weighed. Rats were placed in metabolic chambers and 24 hour urine samples were collected. Ketone levels were measured by Ketostix. Urine proteins were precipitated by acetone, quantified and separated on both the 1D SDS-PAGE and the 2D SDS-PAGE. Protein expression changes between CHOW and HF fed rats were determined and identified using MALDI-TOF mass spectrometry. Protein spots intensities increased and decreased between the CHOW and HF fed rats. Transducin (beta)-like 3 was identified as the only differentially expressed protein, which might serve as a potential biomarker for prediabetes.</p>
384

Development of methods for determining aflatoxins in biological material

Kussak, Anders January 1995 (has links)
In this thesis, it is shown how aflatoxins can be determined in biological material. The thesis is a summary of five papers. Aflatoxins are carcinogenic mycotoxins produced by Aspergillus moulds. Methods were developed for the determination of aflatoxins in samples of airborne dust and human urine collected at feed factories. For the dust samples from such agricultural products as copra, cotton seed and maize, methods were developed for the determination of aflatoxins B1, B2, G1 and G2. For urine samples, methods were developed for analysing the four aflatoxins above that naturally occur in dust, and the metabolites aflatoxins M1 and Q1. Sample preparation of dust samples included solvent extraction, filtration and immunoaffinity column extraction. Urine samples were cleaned up using immunoaffinity column extraction or solid-phase extraction using ethyl bonded-phase columns. All extractions with these columns were automated by means of a laboratory robot. Reversed-phase liquid chromatography was used to separate the aflatoxins in the cleaned-up extracts. Detection was performed by fluorescence after post-column derivatization by addition of bromine. Parameters for the derivatization were studied using factorial designs. To confirm the identity of aflatoxins in naturally contaminated airborne dust samples and spiked urine, liquid chromatography was combined with electrospray mass spectrometry. The detection limits of the aflatoxins in dust samples were in the range 1.8-3.1 ng/g in 10-mg dust samples using fluorescence detection. Aflatoxins were determined in spiked urine down to the 6.8-18 pg/ml level. In naturally contaminated dust of copra and cotton seed, aflatoxins were detected with a content of 9-50 pg/mg of aflatoxin Bi. No aflatoxins could be detected in any urine sample obtained from feed factory workers that were less than 6.8 pg/ml of aflatoxins B1, B2, G1 and G2 and less than 18 pg/ml of aflatoxins M1 and Q1. / <p>Diss. (sammanfattning) Umeå : Univ., härtill 5 uppsatser</p> / digitalisering@umu
385

The Value of Conventional Urine Cytology in the Diagnosis of Residual Tumour after Transurethral Resection of Bladder Carcinomas

Hakenberg, Oliver W., Franke, P., Fröhner, Michael, Manseck, Andreas, Wirth, Manfred 26 February 2014 (has links) (PDF)
Background: Transurethral resection leads to characteristic histological changes of tissue repair (’TUR cystitis‘), which also cause non-specific cytological changes. The aim of this study was to investigate the diagnostic sensitivity and specificity of conventional exfoliative urinary cytology in diagnosing residual urothelial carcinoma after differential transurethral resection. Patients and Methods: 417 urinary cytology specimens of all 374 patients undergoing primary (n = 326) or secondary (n = 91) transurethral resection of urothelial carcinoma of the bladder at our institution between June 1996 and December 1997 were examined. The cytology specimens were stained according to Papanicolaou’s method. The sensitivity and specificity of the cytologic diagnosis and of the tumour grading were compared with histological findings. Results: The overall sensitivity of urine cytology in tumour detection was 77.6% for primary lesions and 74.5% in the detection of residual carcinoma after transurethral resection. The diagnostic specificity was 77% and 84.3% respectively. The degree of sensitivity was dependent on tumour grade and was lower for well differentiated tumours. After transurethral resection, the sensitivity for grade 1 residual tumours was 11%, whereas it was 54% for grade 1 tumours before primary transurethral resection. Conclusions: The inflammatory changes following transurethral resection of primary bladder carcinoma cause reactive cytologic changes that make the diagnosis of well differentiated residual carcinoma more difficult. However, urinary cytology after transurethral resection has the same diagnostic accuracy for medium and poorly differentiated tumours as before primary resection and thus remains a very useful diagnostic tool. / Hintergrund: Transurethrale Resektionen von Blasentumoren führen zu histologischen Veränderungen («TUR Zystitis») im Sinne regenerativer Veränderungen, welche urinzytologisch zu diagnostischen Fehleinschätzungen führen können. Das Ziel unserer Untersuchung war der Vergleich der diagnostischen Sensitivität und Spezifität der Urinzytologie vor transurethraler Resektion mit der bei der Diagnose von Residualtumoren nach transurethraler Resektion. Patienten und Methoden: Untersucht wurden 417 urinzytologische Präparate von allen 374 Patienten, die in unserer Einrichtung zwischen Juni 1996 und Dezember 1997 einer primären (n = 326) oder sekundären (n = 91) transurethralen Resektion von Urothelkarzinomen der Harnblase unterzogen wurden. Die zytologischen Präparate wurden nach Papanicolaou gefärbt. Sensitivität und Spezifität der zytologischen Diagnostik und des Tumorgradings wurden mit den histologischen Befunden verglichen. Ergebnisse: Die Sensitivität der Urinzytologie in der primären Tumorerkennung lag bei 77,6% und die für die Diagnose von Residualtumoren nach transurethraler Resektion bei 74,5%. Die diagnostische Spezifität lag bei 77% bzw. 84,3%. Die Sensitivität war abhängig vom Differenzierungsgrad der Urothelkarzinome und war bei gut differenzierten Tumoren am niedrigsten. Nach transurethraler Resektion betrug die Sensitivität der zytologischen Diagnose für G1-Residualtumore lediglich 11%, während sie für G1-Primärtumore bei 54% lag. Schlußfolgerungen: Die entzündlichenVeränderungen nach transurethraler Resektion verursachen Veränderungen exfoliierter Urothelzellen, welche die zytologische Diagnose von residualen G1-Tumoren erschweren. Die Diagnose mäßig und schlecht differenzierter residualer Urothelkarzinome nach transurethraler Resektion hat dagegen die gleiche Sensitivität und Spezifität wie die bei primärer Untersuchung, so daß die Urinzytologie auch bei der Diagnose von Residualtumoren ein wertvolles diagnostisches Verfahren darstellt. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
386

Phytoestrogen status in relation to sociodemographic factors and biomarkers of bone health in older Brisbane women

Hanna, Katherine Lavina January 2006 (has links)
Background: Phytoestrogens are diphenolic compounds found in plants with a structure and molecular weight similar to oestradiol which enables them to bind to the oestrogen receptor. Isoflavonoids occur mainly within the legume family with highest concentration in soybeans. Lignans are found in a range of plant foods and the richest known source is linseed. Few studies have been published on intake of isoflavonoids and none were located on intake of lignans in Australian women. The validity of methods designed to estimate intake can be assessed using urinary excretion of isoflavonoids and lignans as studies have found an association between intake and excretion of isoflavonoids and lignans. It has been proposed that, through their ability to act like oestrogen, phytoestrogens could decrease bone turnover and attenuate the loss of bone mineral density (BMD) at menopause. The aims of this research were to determine the pattern of intake of isoflavonoids and lignans in 500 women from food and supplements and to assess a questionnaire used to estimate intake using excretion in a sub-sample of 141 women. Associations between usual intake or excretion of isoflavonoids and lignans and biomarkers of bone health were also examined. Methods: A cross-sectional study was conducted involving 500 women aged 40-80 years participating in the Longitudinal Assessment of Ageing in Women (LAW), a 5 year study being conducted in the Betty Byrne Henderson Centre at the Royal Brisbane and Women's Hospital. Subjects were randomly selected from the electoral role and stratified into ten year age groups. Intake of isoflavonoids and lignans from food and supplements was assessed using a specially designed questionnaire containing 110 items. Values for individual items were obtained from published literature and summed to provide average daily intakes of isoflavonoids and lignans (mg/d). A sub-sample of 141 women was recruited to take part in the assessment of the association between phytoestrogen intake and excretion. Participants collected three 24-h urine samples spaced over one week. Samples were analysed using high performance liquid chromatography MS/MS for seven isoflavonoids and four lignans. Bone mineral densities (BMD) of the femur neck, total hip and lumbar spine were measured by dual energy x-ray absorptiometry. Bone formation was assessed using serum bone alkaline phosphatase (bone ALP) and osteocalcin (OC) and bone resorption was assessed using deoxypyridinoline (DPD) and urinary excretion of N-terminal cross-linking telopeptide of type-I collagen (NTX). Potential confounding factors were also evaluated. Statistical analyses were conducted using SPSS for windows (version 10). Participants were defined as consumers if they reported intake of one or more serves of soy or linseed in the prior month. Differences in socio-demographic and lifestyle characteristics between groups were assessed using ANOVA and Chi Square tests. Associations between intake and excretion of phytoestrogens were assessed using Spearman's rank-order correlations () for non-normal data. Phytoestrogen intake was categorised into four groups for the assessment of the association with markers of bone health. Associations between phytoestrogen excretion and markers of bone health were assessed using Pearson's product moment correlations for normal data (r) and Spearman's rank-order correlations for non-normal data. A value of P < 0.05 was taken as statistically significant. Results: Consumption of soy food was reported by 40% and consumption of linseed by 34% of women. Median (range) intakes among soy/linseed consumers for isoflavonoids, 3.87 (0-173) mg/d, and lignans, 2.40 (0.1-33) mg/d, were significantly higher than corresponding intakes among non consumers of 0.005 (0-2.6) and 1.57 (0.4-4.7) mg/d, respectively (P < 0.001). Soy/linseed consumers reported higher intakes of energy (P=0.043), dietary fibre (P=0.003) and polyunsaturated fat (P=0.004); and a higher level of physical activity (P=0.006), SEP (P < 0.001), education (P < 0.001) and supplement use (P < 0.001). Use of non-prescription supplements for menopause in the previous month was reported by 13% of women. A review of supplements available for treatment of menopause indicated that use of soy, red clover, black cohosh and sage could have a role in treatment of menopause symptoms. Evidence supporting the presence of oestrogenic components was available for soy and red clover isoflavonoids only. There was a significant association between intake and excretion of isoflavonoids within the total group (r=0.207, P < 0.05), with a stronger association in soy consumers (r=0.364, P < 0.01). Excretion of isoflavonoids was detected in women who did not report known intake of soy foods, suggesting isoflavonoids could be derived in small amounts from other plant foods or use of soy as an ingredient in processed foods. There was no significant association between intake and excretion of lignans, however both intake and excretion were associated with dietary fibre (r=0.303 and r=0.230, respectively, P < 0.01 for both). Bone ALP was higher among the very low isoflavonoid intake group (P=0.005) for the total sample (P=0.005) and women with BMI≤25 kg/m2 (P=0.002). Data also demonstrated an inverse association between excretion of isoflavonoids and NTX within women with BMI≤25 kg/m2 (r=-0.33, P < 0.05). There was a positive association between lignan excretion and bone ALP in the total sample (r=0.21, P < 0.05) which was strengthened in women with osteoporosis/osteopenia (r=0.41, P < 0.05) and a positive association between lignan excretion and DPD among women with BMI≤25 kg/m2 (ρ=0.28, P < 0.05) All associations remained significant after adjustment for confounding. Conclusions: Few women who chose phytoestrogen-rich foods consumed amounts similar to women with traditional soy-based diets although some achieved high intakes with supplements. Women who consumed soy or linseed foods differed in lifestyle and sociodemographic characteristics that could influence the association with disease in epidemiological studies. Results indicated that the phytoestrogen questionnaire was useful for assessment of isoflavonoids but was not acceptably precise for measurement of lignans. Findings suggest that there is an inverse association between isoflavonoid status and bone ALP and NTX although the precise mechanism of action has not been clarified. The association between lignan intake and bone is less well understood; however findings of a positive association with bone ALP indicate that further research on the lignan content of foods and the inclusion of lignans in studies is warranted.
387

Concentrações de flúor em saliva e urina de crianças após uso de produtos fluoretados. / Fluoride concentrations in saliva and urine of children after use of fluoride products

Almeida, Danielle Bezerra 08 December 2009 (has links)
Made available in DSpace on 2015-05-14T12:56:07Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2499199 bytes, checksum: ba2f9cd3497696e4d2f7095983ffe2db (MD5) Previous issue date: 2009-12-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to measure the bioavailability of fluoride in saliva and to observe the pattern of urinary fluoride excretion in children exposed to topical fluoride products of professional use. Seventeen children of 6- 12-years-old, both genders with active white spots on smooth surfaces, no cavities and needing fluoride treatment were included in the study. All volunteers (n=17) received toothbrushes and fluoridated toothpaste (1,100 ppm, 11 volunteers) and no fluoride (6 volunteers) eight days before fluoride a application. A wash-out period of 7 days was established before and after the exposure of neutral gel fluoride (9,000 ppm), foam (12,300 ppm) and varnish (22,600 ppm). Except for the varnish, the fluoridated gel (5g) and foam (1.5g) were applied in trays. /the products were applied for one minute covering all buccal surfaces. Saliva was collected in the following times: 0, 3, 6, 9, 15, 30, 45 and 60 minutes. Urine was collected covering the 24 hours of baseline and after application of the products covering 11 and 13 hours of collection to cover day and night periods as (7:00-18:00 h) and (18:00-7:00 h). Fluoride was measured with the aid of ion specific electrode ORION (9409BN) coupled to a potenciometer (720 A,ThermoOrion). Data statistical analyses were performed in SPSS v. 13.0 applying p< 0.05. The results indicated a higher concentration of fluoride in saliva after 3 minutes of using varnish, foam and gel, the values are 95.02 ± 82.2 ppmF, ppmF 41.0 ± 75.51 and 99.33 ± 59, 8 ppm F, respectively. The excretion of fluoride in urine was higher for varnish, foam and gel, the values are 1.1 ± 7.1 ppm F, 0.6 ± 0.3 ppm F and 0.6 ± 0.6 ppm F, respectively. It can be concluded that the highest values of salivary fluoride regardless the time of measurement were achieved by the fluoride varnish. For the urinary fluoride followed a similar trend showing higher values for the varnish and suggesting that this product can produce a high ingestion of fluoride. / O objetivo desse estudo foi de mensurar a concentração de flúor em saliva e na urina de crianças expostas a fluoretos tópicos de uso profissional. O delineamento desse estudo é clínico, aleatório e cruzado. Participaram 17 crianças com idades entre 6 e 12 anos, de ambos os sexos, com manchas brancas ativas em superfícies lisas, necessitando de fluorterapia. Escovas e dentifrícios foram fornecidos aos voluntários, onde n= 11 receberam dentifrício de 1.100 ppm e n= 6 dentifrício sem flúor. Os produtos fluoretados utilizados foram: gel neutro (9.000 ppm), espuma neutra (12.300 ppm) e verniz (22.600 ppm). As aplicações do gel (5g) e a espuma (1,5g) foram em moldeiras por 1 minuto e o verniz (0,5g) com pincel, cobrindo toda a superfície vestibular do dentes. As coletas de saliva foram feitas no dia da aplicação dos produtos fluoretados nos seguintes tempos: 0, 3, 6, 9, 15, 30, 45 e 60 minutos. As coletas de urina foram feitas por 24 horas. Sendo, 24 horas dividida em dois períodos: diurno ou 11horas (coleta das 7:00 h às 18:00 h) e período noturno ou de 13 horas (coleta das 18:00 h às 7:00 h). Nas análises das amostras de saliva e urina utilizou-se um eletrodo combinado íon-específico da ORION (9409BN) com eletrodo de referência (900200), ambos acoplados a um potenciômetro 720 A (ThermoOrion). Os dados foram digitados no SPSS v. 13.0, submetidos a testes estatísticos e considerados significativos com p< 0,05. Os resultados indicaram uma maior concentração de flúor na saliva após 3 minutos de uso do verniz, gel e espuma, os valores (ppmF) foram de 99,33 ± 59,8; 95,02 ± 82,2 e 75,51 ± 41,0, respectivamente. A excreção de flúor na urina foi maior para verniz, espuma e gel com valores (ppmF) de 1,1± 7,1; 0,6 ± 0,3 e 0,6± 0,6, respectivamente. Pode-se concluir que os valores mais elevados de flúor na saliva independentemente do tempo de medição foram obtidos com o verniz. Para a excreção do flúor seguiu uma tendência semelhante, apresentando valores mais elevados para o verniz e sugerindo que este produto pode produzir uma elevada ingestão de flúor.
388

Doença da urina do xarope do bordo no Brasil : um panorama das duas últimas décadas

Herber, Silvani January 2012 (has links)
Introdução: A Doença da Urina do Xarope do Bordo (DXB) é um Erro Inato do Metabolsimo (EIM), causada pela deficiência da atividade do complexo enzimático desidrogenase dos L-cetoácidos de cadeia ramificada (CACR). O programa público brasileiro de triagem neonatal não inclui o diagnóstico e o tratamento da DXB. Objetivo: Caracterizar aspectos relacionados ao diagnóstico e ao tratamento de pacientes brasileiros com DXB. Metodologia: Estudo retrospectivo. Os pacientes foram identificados a partir dos registros de laboratório considerado referência nacional para o diagnóstico de DXB, e de contato com demais serviços nacionais de referência em genética médica. O diagnóstico foi realizado entre 1992-2011. Os dados analisados foram obtidos a partir da revisão de prontuários. Resultados: Oitenta e três pacientes, oriundos de 75 famílias, foram incluídos no estudo (mediana de idade= 3 anos; IQ25- 75= 0,57-7). A mediana da idade de início dos sintomas foi de 10 dias (IQ= 5-30), enquanto que a mediana da idade ao diagnóstico foi de 60 dias (IQ= 29-240, p= 0,001). Apenas três (3,6%) pacientes foram diagnosticados antes de desenvolverem manifestações clínicas. A comparação entre os pacientes com (n=12) e sem (n=71) diagnóstico precoce mostrou que o mesmo associa-se com a presença de história familiar positiva e diminuição da prevalência de manifestações clínicas ao diagnóstico, mas não com melhor resultado; além disso, a maioria desses diagnósticos foi realizada entre 2002-2011 (n= 10/12). Considerando a amostra total, 98,8% dos pacientes apresentam atraso de desenvolvimento neuropsicomotor. Conclusão: Os pacientes com DXB são diagnosticados tardiamente no Brasil, de forma que as complicações associadas a esta condição não são prevenidas. Entretanto, existem indícios de que está havendo um melhora gradual desse panorama desde a última década. Os nossos dados indicam que o diagnóstico precoce dessa condição, mesmo que em fase sintomática, associa-se a um melhor prognóstico do paciente. Sugere-se a elaboração de políticas públicas específicas para doenças raras no país. / Introduction: Maple syrup urine disease (MSUD) is an Inborn Errors of Metabolism, is caused by a deficiency in activity of the branched-chain L-keto acid dehydrogenase complex. The Brazilian neonatal screening program does not include the diagnosis and treatment of MSUD. Objective: To draw a profile of aspects related to the diagnosis and treatment of Brazilian patients who received. Methods: In this retrospective study, patients were identified through a search of records from a national reference laboratory for the diagnosis of MSUD and through contact with other medical genetics services across Brazil. A diagnosis of MSUD between 1992 and 2011. Data were collected by means of a chart review. Results: Eighty-three patients from 75 families were enrolled in the study (median age 3 years; interquartile range, 0.57–7). Median age at onset of symptoms was 10 days (IQR 5–30), whereas median age at diagnosis was 60 days (IQR 29–240, p=0.001). Only three (3.6%) patients were diagnosed before the onset of clinical manifestations. A comparison between patients with (n=12) and without (n=71) an early diagnosis show that early diagnosis is associated with the presence of positive familial history and decreased prevalence of clinical manifestations at the time of diagnosis, but not with a better outcome. Overall, 98.8% of patients have some psychomotor or neurodevelopmental delay. Conclusion: In Brazil, patients with MSUD receive a late diagnosis and show neurological compromise and poor survival even with an early diagnosis. We suggest that specific public policies for rare diseases should be developed and implemented in the country.
389

Dynamika Na, K a acidobazického výlučku v moči u sezónně telených krav. / Dynamics of sodium, potassium and acid-base in urine of seasonal calving cows

FAJMON, Tomáš January 2013 (has links)
In this work, there was observed the influence of feeding an anionic salt on acid-base value in the urine (ABV) and on a level of the calcium in the urine in high yielding dairy cows. This mineral ingredient was tested for two feeding rates: winter - conserved, summer - pasture and was fed in a rate 450 g per a cow and a day. In the winter experimental period there were found no changes in AVB and the effect of Rindavit MF Sauer wasn´t expressed. In the sum-mer experimental period the influence of Rindavit MF Sauer on acid-base balance was fully expressed although the high potassium level in the feed rate. We found statistically significant differences between control and experimental group at observing levels of calcium and the effect of the anionic salt was shown. There was found no case of the milk fever in experimental group cows dduring the whole test. By contrast, there were recorded two cases of the milk fever in the control group cows. At feeding the anionic salt, we didn't find any negative effect on the acid - base balance and the health of the cows.
390

Aplicações de métodos quimiométricos e de técnicas analíticas em amostras alimentícias e farmacêuticas / Application of chemometrical methods and analytical techniques in food and pharmaceutical samples

Jéssica da Silva Alves de Pinho 27 February 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esse trabalho compreende dois diferentes estudos de caso: o primeiro foi a respeito de um medicamento para o qual foi desenvolvida uma metodologia para determinar norfloxacino (NOR) por espectrofluorimetria molecular e validação por HPLC. Primeiramente foi desenvolvida uma metodologia por espectrofluorimetria onde foram feitos alguns testes preliminares a fim de estabelecer qual valor de pH iria fornecer a maior intensidade de emissão. Após fixar o pH foi feita a determinação de NOR em padrões aquosos e soluções do medicamento usando calibração univariada. A faixa de concentração trabalhada foi de 0500 &#956;g.L-1. O limite de detecção para o medicamento foi de 6,9 &#956;g.L-1 enquanto que o de quantificação foi de 24,6 &#956;g.L-1. Além dessas, outras figuras de mérito também foram estimadas para desenvolvimento da metodologia e obtiveram resultados muito satisfatórios, como por exemplo, os testes de recuperação no qual a recuperação do analito foi de 99.5 a 103.8%. Para identificação e quantificação do NOR da urina foi necessário diluir a amostra de urina (estudada em dois diferentes níveis de diluição: 500 e 1000 x) e também uso do método da adição de padrão (na mesma faixa de concentração usada para medicamento). Após a aquisição do espectro, todos foram usados para construção do tensor que seria usado no PARAFAC. Foi possível estimar as figuras de mérito como limite de detecção de 11.4 &#956;g.L-1 and 8.4 &#956;g.L-1 (diluição de 500 e 1000 x respectivamente) e limite de quantificação de 34 &#956;g.L-1 e 25.6 &#956;g.L-1 (diluição de 500 x e 1000 x respectivamente). O segundo estudo de caso foi na área alimentícia no qual se usou espectroscopia NIR e FT MIR acopladas a quimiometria para discriminar óleo de soja transgênica e não transgênica. Os espectros dos óleos não mostraram diferença significativa em termos visuais, sendo necessário usar ferramentas quimiométricas capazes de fazer essa distinção. Tanto para espectroscopia NIR quanto FT MIR foi feito o PCA a fim de identificar amostras discrepantes e que influenciariam o modelo de forma negativa. Após efetuar o PCA, foram usadas três diferentes técnicas para discriminar os óleos: SIMCA, SVM-DA e PLS-DA, sendo que para cada técnica foram usados também diferentes pré processamento. No NIR, apenas para um pré processamento se obteve resultados satisfatórios nas três técnicas, enquanto que para FT-MIR ao se usar PLS-DA se obteve 100% de acerto na classificação para todos os pré processamentos / This paper comprises two different researches: the firts one was related to a medicament for which was developed a methodology to quantify Norfloxacin (NOR) by molecular spectrofluorimetry and validation by HPLC. First of all, was developed a methodology for spectrofluorimetry where were done some preliminary tests to establish which value of pH would provide the highest emission intensity. After fix pH, it was performed NOR determination in aqueous standard and medicament using univariate calibration. The concentration range was 0-500 &#956;g.L-1. The limit of detection for medicament was 6,9 &#956;g.L-1 while the limit of detection was 24,6 &#956;g.L-1. Beyond that, other figures of merit were also estimated for developing methodology and offered results quite satisfactory, such as recovering tests in which analyte recovery was 99.5 - 103.8%. For identify and quantify NOR in urine was necessary to dilute the samples (studied in two different levels: 500 and 1000 X) and also standar method addition (in same concentration range used for medicament). After spectra acquisition, all of them were used to built the tensor that would be used in PARAFAC. It was possible to estimate figures of merit such as limit of detection: 11.4 &#956;g.L-1 and 8.4 &#956;g.L-1 (dilution of 500 and 1000 X respectively) and limit of quantification: 34 &#956;g.L-1 and 25.6 &#956;g.L-1 (dilution of 500 and 1000 X, respectively). The second studied case was in food area in which was used NIR and FT-MIR spectroscopy coupled with chemometric to discriminate transgenic and no transgenic soybean oil. Oils spectra did not show significative difference in visual terms, being necessary using chemometric tools capable of perform this distinction. For NIR and FT-MIR spectroscopy it was performed PCA that aimed identify anomalous samples that would be a negative influence. After perform PCA were used three different techniques to discriminate oils samples: SIMCA, SVM-DA and PLS-DA, being used for each technique different preprocessing. In NIR, only for one preprocessing it was obtained good results for three techniques while in FT-MIR when PLS-DA was used it was achieved 100% in classification for all preprocessing

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