19 resultados para Instrumental-variable Methods

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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SynopsisBackgroundCellulite refers to skin relief alterations in womens thighs and buttocks, causing dissatisfaction and search for treatment. Its physiopathology is complex and not completely understood. Many therapeutic options have been reported with no scientific evidence about benefits. The majority of the studies are not controlled nor randomized; most efficacy endpoints are subjective, like not well-standardized photographs and investigator opinion. Objective measures could improve severity assessment. Our purpose was to correlate non-invasive instrumental measures and standardized clinical evaluation.MethodsTwenty six women presenting cellulite on buttocks, aged from 25 to 41, were evaluated by: body mass index; standardized photography analysis (10-point severity and 5-point photonumeric scales) by five dermatologists; cutometry and high-frequency ultrasonography (dermal density and dermis/hypodermis interface length). Quality of life impact was assessed. Correlations between clinical and instrumental parameters were performed.ResultsGood agreement among dermatologists and main investigator perceptions was detected. Positive correlations: body mass index and clinical scores; ultrasonographic measures. Negative correlation: cutometry and clinical scores. Quality of life score was correlated to dermal collagen density.ConclusionCellulite caused impact in quality of life. Poor correlation between objective measures and clinical evaluation was detected. Cellulite severity assessment is a challenge, and objective parameters should be optimized for clinical trials.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Tigecycline is a new glycylcycline with an expanded broad-spectrum antibiotic, including inhibition of Gram-positive, Gram-negative, atypical, anaerobic, and antibiotic-resistant organisms. Trials have demonstrated that tigecycline is noninferior to the comparators for the treatment of complicated skin and skin structure infections as well as complicated intra-abdominal infections. Tigecycline is only available as an intravenous preparation and analytical methods to its quantitation in pharmaceutical products has not been published to date. This review examined tigecycline characteristics, the spectrum and mechanism of action, pharmacokinetics, applications, and, mainly, the instrumental conditions of published chromatographic methods used to measure tigecycline, its metabolites, and some analogs in clinical and biologic research.

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O losartano potássico é um agente anti-hipertensivo não peptídico, que exerce sua ação por bloqueio específico dos receptores da angiotensina II. Este trabalho propôs a validação e aplicação de métodos analíticos orientados ao controle de qualidade de losartano potássico 50 mg na forma farmacêutica cápsula, utilizando a espectrofotometria direta e derivada de primeira ordem na região do UV. Baseado nas características espectrofotométricas de losartano potássico, um sinal a 205 nm do espectro de ordem zero e um sinal a 234 nm do espectro de primeira derivada foram adequados para a quantificação. Os resultados foram usados para comparar essas duas técnicas instrumentais. O coeficiente de correlação entre as respostas e as concentrações de losartano potássico na faixa de 3,0-7,0 mg L-1 e 6,0-14,0 mg L-1 para espectrofotometria direta e derivada de primeira ordem em solução aquosa, respectivamente, foi de (r) of 0,9999 para ambos os casos. Os métodos foram aplicados para quantificação de losartano potássico em cápsulas obtidas de farmácias de manipulação locais e demonstraram ser eficientes, fáceis de aplicar e de baixo custo. Além disso, não necessitam de reagentes poluentes e requerem equipamentos economicamente viáveis.

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The general assumption under which the (X) over bar chart is designed is that the process mean has a constant in-control value. However, there are situations in which the process mean wanders. When it wanders according to a first-order autoregressive (AR (1)) model, a complex approach involving Markov chains and integral equation methods is used to evaluate the properties of the (X) over bar chart. In this paper, we propose the use of a pure Markov chain approach to study the performance of the (X) over bar chart. The performance of the chat (X) over bar with variable parameters and the (X) over bar with double sampling are compared. (C) 2011 Elsevier B.V. All rights reserved.

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Aims: To estimate the prevalence and correlates of cognitive impairment (CI) among the elderly in a general hospital. Methods: A cross-sectional study, including 200 Brazilian inpatients aged 60 years or over, using the Mini Mental State Examination to evaluate CI (dependent variable), and the Geriatric Depression Scale and the Katz and Lawton Index to evaluate basic (BADL) and instrumental activities of daily living (IADL). Results: 56% were women, 29% were dependent for BADL and 77.5% for IADL. The prevalence of CI was 29% and, in the logistic regression, it remained associated with higher age (1 74 years old), number of previous hospitalizations (1 3) and dependency for BADL (being dependent raised the odds of being cognitively impaired). Conclusions: It is essential to train the hospital staff to properly assist these patients, and to orient and support their caregivers. Copyright (C) 2009 S. Karger AG, Basel

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OBJETIVO: Analisar os efeitos de seis meses de intervenção de um programa de atividade física sobre os distúrbios neuropsiquiátricos e o desempenho nas atividades instrumentais da vida diária de idosos com Doença de Alzheimer (DA). MÉTODOS: Foram recrutados 20 pacientes nos estágios entre leve e moderado da DA. Segundo o escore clínico de demência (CDR), foram distribuídos em dois grupos: o grupo treinamento (GT), composto por dez mulheres que participaram de um program de exercícios físicos por um período de seis meses, e o grupo controle (GC), composto por dez outras participantes que não realizaram nenhum tipo de intervenção motora estruturada durante o mesmo período. Todas as participantes foram avaliadas por meio do Miniexame do Estado Mental, para obtenção da caracterização cognitiva; Inventário Neuropsiquiátrico, para identificação dos distúrbios neuropsiquiátricos mais prevalentes e Questionário de Atividades Instrumentais de Pfeffer, para verificação do grau de comprometimento funcional. RESULTADOS: Os participantes do GC mostraram uma deterioração tanto no desempenho das atividades instrumentais quanto na intensificação dos distúrbios neuropsiquiátricos, quando comparados os momentos pré e pós-intervenção. CONCLUSÃO: O GT demonstrou uma atenuação da intensificação dos distúrbios neuropsiquiátricos e do desempenho funcional em relação ao grupo sedentário.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The acidic ninhydrin spectrophotometric method (ANSM) for quantitative determination of free and bound sialic acid of milk glycoprotein has been proved to be fast and efficient for routine detection of fraudulent addition of rennet whey to fluid milk. In this research the ANSM was compared with the high performance liquid chromatography (HPLC) method, internationally recommended for caseinomacropeptide (CMP) determination, which besides its high accuracy is more sophisticated and requires trained personnel. For several sample conditions (raw milk and milk with variable added amounts of rennet cheese whey), the methods showed an excellent linear correlation, with r = 0.981 when milk was deproteinized with a 120 g.L-1 final concentration of trichloroacetic acid (TCA) concentration. The best correlations could be seen with final concentrations of 100 g.L-1 and 80 g.L-1 TCA; respectively, r = 0.992 and 0.993.

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The usual practice in using a control chart to monitor a process is to take samples of size n from the process every h hours. This article considers the properties of the X̄ chart when the size of each sample depends on what is observed in the preceding sample. The idea is that the sample should be large if the sample point of the preceding sample is close to but not actually outside the control limits and small if the sample point is close to the target. The properties of the variable sample size (VSS) X̄ chart are obtained using Markov chains. The VSS X̄ chart is substantially quicker than the traditional X̄ chart in detecting moderate shifts in the process.

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Recent theoretical studies have shown that the X̄ chart with variable sampling intervals (VSI) and the X̄ chart with variable sample size (VSS) are quicker than the traditional X̄ chart in detecting shifts in the process. This article considers the X̄ chart with variable sample size and sampling intervals (VSSI). It is assumed that the amount of time the process remains in control has exponential distribution. The properties of the VSSI X̄ chart are obtained using Markov chains. The VSSI X̄ chart is even quicker than the VSI or VSS X̄ charts in detecting moderate shifts in the process.

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A methodology to define favorable areas in petroleum and mineral exploration is applied, which consists in weighting the exploratory variables, in order to characterize their importance as exploration guides. The exploration data are spatially integrated in the selected area to establish the association between variables and deposits, and the relationships among distribution, topology, and indicator pattern of all variables. Two methods of statistical analysis were compared. The first one is the Weights of Evidence Modeling, a conditional probability approach (Agterberg, 1989a), and the second one is the Principal Components Analysis (Pan, 1993). In the conditional method, the favorability estimation is based on the probability of deposit and variable joint occurrence, with the weights being defined as natural logarithms of likelihood ratios. In the multivariate analysis, the cells which contain deposits are selected as control cells and the weights are determined by eigendecomposition, being represented by the coefficients of the eigenvector related to the system's largest eigenvalue. The two techniques of weighting and complementary procedures were tested on two case studies: 1. Recôncavo Basin, Northeast Brazil (for Petroleum) and 2. Itaiacoca Formation of Ribeira Belt, Southeast Brazil (for Pb-Zn Mississippi Valley Type deposits). The applied methodology proved to be easy to use and of great assistance to predict the favorability in large areas, particularly in the initial phase of exploration programs. © 1998 International Association for Mathematical Geology.

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This paper presents a control method for a class of continuous-time switched systems, using state feedback variable structure controllers. The method is applied to the control of a non-trivial dc-dc power converter and a simple and inexpensive control circuit design, that was simulated using the software PSpice, is proposed. The design is based on Lyapunov-Metzler-SPR systems and the performance of the resulting control system is superior to that afforded by a recently proposed alternative sliding-mode control technique. © 2011 IFAC.

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This study describes the comparison of three methods for genotyping of Mycobacterium tuberculosis, namely MIRU-VNTR (mycobacterial interspersed repetitive units-variable number of tandem repeats), spoligotyping and, for the first time, MLST (Multilocus Sequence Typing). In order to evaluate the discriminatory power of these methods, a total of 44 M. tuberculosis isolates obtained from sputum specimens of patients from Brazil were genotyped. Among the three methods, MLST showed the lowest discriminatory power compared to the other two techniques. MIRU-VNTR showed better discriminatory power when compared to spoligotyping, however, the combination of both methods provides the greatest level of discrimination and therefore this combination is the most useful genotyping tool to be applied to M. tuberculosis isolates. © 2013 Elsevier B.V.