985 resultados para multivariate electronic spectroscopy


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Background: Population-based cohort studies of risk factors of stroke are scarce in developing countries and none has been done in the African region. We conducted a longitudinal study in the Seychelles (Indian Ocean, east of Kenya), a middle-income island state where the majority of the population is of African descent. Such data in Africa are important for international comparison and for advocacy in the region. Methods: Three examination surveys of cardiovascular risk factors were performed in independent samples representative of the general population aged 25-64 in 1989, 1994 and 2004 (n=1081, 1067, and 1255, respectively). Baseline risk factors data were linked with cause-specific mortality from vital statistics up to May 2007 (all deaths are medically certified in the Seychelles and kept in an electronic database). We considered stroke (any type) as a cause of death if the diagnosis was reported in any of the 4 fields in the death certificates for underlying and concomitant causes of death. Results. Among the 2479 persons aged 35-64 at baseline, 280 died including 56 with stroke during follow up (maximum: 18.2 years; mean: 10.2 years). In this age range, age-adjusted mortality rates (/100'000/year) were 969 for all cause and 187 for stroke; age-adjusted prevalence of high blood pressure (≥140/90 mmHg) was 48%. In multivariate Cox survival time regression, stroke mortality was increased by 18% and 35% for a 10-mmHg increase in systolic, respectively diastolic BP (p<0.001). Stroke mortality was also associated with age, smoking ≥5 cigarettes vs. no smoking (HR: 2.4; 95% CI: 1.2-4.8) and diabetes (HR: 1.9; 1.02-3.6) but not with sex, LDL-cholesterol intake, alcohol intake and professional occupation. Conclusion. This first population-based cohort study in the African region demonstrates high mortality rates from stroke in middle-aged adults and confirms associations with high BP and other risk factors. This emphasizes the importance of reducing BP and other modifiable risk factors in high risk individuals and in the general population as a main strategy to reduce the burden of stroke.

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In the Earth's carbon cycle, C stocks in the soil are higher than in vegetation and atmosphere. Maintaining and conserving organic C concentrations in the soil by specific management practices can improve soil fertility and productivity. The aim of this study was to evaluate the impact of agricultural management techniques and influence of water regime (flooded or drained) on the structure of humic substances by excitation/emission matrix fluorescence. Six samples of a Planosol (Planossolo by the Brazilian System of Soil Classification) were collected from a rice field. Humic substances (HS) were extracted from flooded and drained soil under different agricultural management techniques: conventional tillage, reduced tillage and grassland. Two peaks at a long emission wavelength were observed in the EEM spectra of HA whereas those of the corresponding FA contained a unique fluorophore at an intermediate excitation/emission wavelength pair (EEWP) value. The fluorescence intensity measured by total luminescence (FI TL) of HA was lower than that of the corresponding FA. A comparison of all samples (i.e., the HA values compared to each other) revealed only slight differences in the EEWP position, but the FI TL values were significantly different. In this soil, anoxic conditions and reduced tillage (little plowing) seem to favor a higher degree of humification of the soil organic matter compared with aerated conditions and conventional tillage.

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A series of InxAl12xAs samples (0.51,x,0.55) coherently grown on InP was studied in order to measure the band-gap energy of the lattice matched composition. As the substrate is opaque to the relevant photon energies, a method is developed to calculate the optical absorption coefficient from the photoluminescence excitation spectra. The effect of strain on the band-gap energy has been taken into account. For x50.532, at 14 K we have obtained Eg05154966 meV. © 1997 American Institute of Physics.

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BACKGROUND/OBJECTIVES: To assess the distribution of interleukin (IL)-1β, IL-6, tumour necrosis factor (TNF)-α and C-reactive protein (CRP) according to the different definitions of metabolically healthy obesity (MHO). SUBJECTS/METHODS: A total of 881 obese (body mass index (BMI) > or =30 kg/m2) subjects derived from the population-based CoLaus Study participated in this study. MHO was defined using six sets of criteria including different combinations of waist, blood pressure, total high-density lipoprotein cholesterol or low-density lipoprotein -cholesterol, triglycerides, fasting glucose, homeostasis model, high-sensitivity CRP, and personal history of cardiovascular, respiratory or metabolic diseases. IL-1β, IL-6 and TNF-α were assessed by multiplexed flow cytometric assay. CRP was assessed by immunoassay. RESULTS: On bivariate analysis some, but not all, definitions of MHO led to significantly lower levels of IL-6, TNF-α and CRP compared with non-MH obese subjects. Most of these differences became nonsignificant after multivariate analysis. An posteriori analysis showed a statistical power between 9 and 79%, depending on the inflammatory biomarker and MHO definition considered. Further increasing sample size to overweight+obese individuals (BMI > or =25 kg/m2, n=2917) showed metabolically healthy status to be significantly associated with lower levels of CRP, while no association was found for IL-1β. Significantly lower IL-6 and TNF-α levels were also found with some but not all MHO definitions, the differences in IL-6 becoming nonsignificant after adjusting for abdominal obesity or percent body fat. CONCLUSIONS: MHO individuals present with decreased levels of CRP and, depending on MHO definition, also with decreased levels in IL-6 and TNF-α. Conversely, no association with IL-1β levels was found.

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INTRODUCTION: The cell surface endopeptidase CD10 (neutral endopeptidase) and nuclear factor-κB (NF-κB) have been independently associated with prostate cancer (PC) progression. We investigated the correlations between these two factors and their prognostic relevance in terms of biochemical (prostate-specific antigen, PSA) relapse after radical prostatectomy (RP) for localized PC. PATIENTS AND METHODS: The immunohistochemical expression of CD10 and NF-κB in samples from 70 patients who underwent RP for localized PC was correlated with the preoperative PSA level, Gleason score, pathological stage and time to PSA failure. RESULTS: CD10 expression was inversely associated with NF-κB expression (p < 0.001), stage (p = 0.03) and grade (p = 0.003), whereas NF-κB was directly related with stage (p = 0.006) and grade (p = 0.002). The median time to PSA failure was 56 months. CD10 and NF-κB were directly (p < 0.001) and inversely (p < 0.001) correlated with biochemical recurrence-free survival, respectively. CD10 expression (p = 0.022) and stage (p = 0.018) were independently associated with time to biochemical recurrence. CONCLUSION: Low CD10 expression is an adverse prognostic factor for biochemical relapse after RP in localized PC, which is also associated with high NF-κB expression. Decreased CD10 expression which would lead to increased neuropeptide signaling and NF-κB activity may be present in a subset of early PCs.

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OBJECTIVES: To determine whether baseline demographic, clinical, articular and laboratory variables predict methotrexate (MTX) poor response in polyarticular-course juvenile idiopathic arthritis. METHODS: Patients newly treated for 6 months with MTX enrolled in the Paediatric Rheumatology International Trials Organization (PRINTO) MTX trial. Bivariate and logistic regression analyses were used to identify baseline predictors of poor response according to the American College of Rheumatology pediatric (ACR-ped) 30 and 70 criteria. RESULTS: In all, 405/563 (71.9%) of patients were women; median age at onset and disease duration were 4.3 and 1.4 years, respectively, with anti-nuclear antibody (ANA) detected in 259/537 (48.2%) patients. With multivariate logistic regression analysis, the most important determinants of ACR-ped 70 non-responders were: disease duration > 1.3 years (OR 1.93), ANA negativity (OR 1.77), Childhood Health Assessment Questionnaire (CHAQ) disability index > 1.125 (OR 1.65) and the presence of right and left wrist activity (OR 1.55). Predictors of ACR-ped 30 non-responders were: ANA negativity (OR 1.92), CHAQ disability index > 1.14 (OR 2.18) and a parent's evaluation of child's overall well-being < or = 4.69 (OR 2.2). CONCLUSION: The subgroup of patients with longer disease duration, ANA negativity, higher disability and presence of wrist activity were significantly associated with a poorer response to a 6-month MTX course.

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PURPOSE: The combination of embolic beads with a multitargeted tyrosine kinase inhibitor that inhibits tumor vessel growth is suggested as an alternative and improvement to the current standard doxorubicin-eluting beads for use in transarterial chemoembolization. This study demonstrates the in vitro loading and release kinetics of sunitinib using commercially available embolization microspheres and evaluates the in vitro biologic efficacy on cell cultures and the resulting in vivo pharmacokinetics profiles in an animal model. MATERIALS AND METHODS: DC Bead microspheres, 70-150 µm and 100-300 µm (Biocompatibles Ltd., Farnham, United Kingdom), were loaded by immersion in sunitinib solution. Drug release was measured in saline in a USP-approved flow-through apparatus and quantified by spectrophotometry. Activity after release was confirmed in cell culture. For pharmacokinetics and in vivo toxicity evaluation, New Zealand white rabbits received sunitinib either by intraarterial injection of 100-300 µm sized beads or per os. Plasma and liver tissue drug concentrations were assessed by liquid chromatography-tandem mass spectroscopy. RESULTS: Sunitinib loading on beads was close to complete and homogeneous. A total release of 80% in saline was measured, with similar fast-release profiles for both sphere sizes. After embolization, drug plasma levels remained below the therapeutic threshold (< 50 ng/mL), but high concentrations at 6 hours (14.9 µg/g) and 24 hours (3.4 µg/g) were found in the liver tissue. CONCLUSIONS: DC Bead microspheres of two sizes were efficiently loaded with sunitinib and displayed a fast and almost complete release in saline. High liver drug concentrations and low systemic levels indicated the potential of sunitinib-eluting beads for use in embolization.

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Irrigation with treated domestic sewage wastewater (TSE) is an agricultural practice to reduce water requirements of agroecossystems and the nutrient load impact on freshwaters, but adverse effects on soil chemical (salinization, sodification, etc.) and soil physical properties (alteration in soil porosity and hydraulic conductivity, etc.) have been reported. This study aimed to define some relationships among these changes in an Oxisol using multivariate analysis. Corn (Zea mays L.) and sunflower (Helianthus annuus L.) were grown for two years, irrigated with TSE. The following soil properties were determined: Ca2+; Mg2+; Na+; K+ and H + Al contents, cationic exchangeable capacity (CEC), sum of bases (SB), base saturation (V), texture (sand, silt and clay), macro-, micro-, and cryptoporosity (V MA, V MI and V CRI), water content at soil saturation (θS) and at field capacity (θFC), residual water content (θR), soil bulk density (d s), water dispersed clay (WDC) and saturated hydraulic conductivity (K SAT). Factor analysis revealed the following six principal factors: Fine Porosity (composed of Na+; K+; WDC, θR, θRFC, and V CRI); Large Porosity (θS, d s, V MA, Vs); Soil CEC (Ca2+; Mg2+; CEC, SB, V); Soil Acidity (H + Al); and Soil Texture (factors 5 and 6). A dual pore structure appears clearly to the factors 1 and 2, with an apparent relationship between fine porosity and the monovalent cations Na+ and K+. The irrigation (with potable sodic tap water or sewage wastewater) only had a significant effect on Fine Porosity and Large Porosity factors, while factors 3 and 4 (Soil CEC and Soil Acidity) were correlated with soil depth. The main conclusion was a shift in pore distribution (large to fine pores) during irrigation with TSE, which induces an increase of water storage and reduces the capacity of drainage of salts.

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BACKGROUND Current guidelines give recommendations for preferred combination antiretroviral therapy (cART). We investigated factors influencing the choice of initial cART in clinical practice and its outcome. METHODS We analyzed treatment-naive adults with human immunodeficiency virus (HIV) infection participating in the Swiss HIV Cohort Study and starting cART from January 1, 2005, through December 31, 2009. The primary end point was the choice of the initial antiretroviral regimen. Secondary end points were virologic suppression, the increase in CD4 cell counts from baseline, and treatment modification within 12 months after starting treatment. RESULTS A total of 1957 patients were analyzed. Tenofovir-emtricitabine (TDF-FTC)-efavirenz was the most frequently prescribed cART (29.9%), followed by TDF-FTC-lopinavir/r (16.9%), TDF-FTC-atazanavir/r (12.9%), zidovudine-lamivudine (ZDV-3TC)-lopinavir/r (12.8%), and abacavir/lamivudine (ABC-3TC)-efavirenz (5.7%). Differences in prescription were noted among different Swiss HIV Cohort Study sites (P < .001). In multivariate analysis, compared with TDF-FTC-efavirenz, starting TDF-FTC-lopinavir/r was associated with prior AIDS (relative risk ratio, 2.78; 95% CI, 1.78-4.35), HIV-RNA greater than 100 000 copies/mL (1.53; 1.07-2.18), and CD4 greater than 350 cells/μL (1.67; 1.04-2.70); TDF-FTC-atazanavir/r with a depressive disorder (1.77; 1.04-3.01), HIV-RNA greater than 100 000 copies/mL (1.54; 1.05-2.25), and an opiate substitution program (2.76; 1.09-7.00); and ZDV-3TC-lopinavir/r with female sex (3.89; 2.39-6.31) and CD4 cell counts greater than 350 cells/μL (4.50; 2.58-7.86). At 12 months, 1715 patients (87.6%) achieved viral load less than 50 copies/mL and CD4 cell counts increased by a median (interquartile range) of 173 (89-269) cells/μL. Virologic suppression was more likely with TDF-FTC-efavirenz, and CD4 increase was higher with ZDV-3TC-lopinavir/r. No differences in outcome were observed among Swiss HIV Cohort Study sites. CONCLUSIONS Large differences in prescription but not in outcome were observed among study sites. A trend toward individualized cART was noted suggesting that initial cART is significantly influenced by physician's preference and patient characteristics. Our study highlights the need for evidence-based data for determining the best initial regimen for different HIV-infected persons.

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AIMS: We studied the respective added value of the quantitative myocardial blood flow (MBF) and the myocardial flow reserve (MFR) as assessed with (82)Rb positron emission tomography (PET)/CT in predicting major adverse cardiovascular events (MACEs) in patients with suspected myocardial ischaemia. METHODS AND RESULTS: Myocardial perfusion images were analysed semi-quantitatively (SDS, summed difference score) and quantitatively (MBF, MFR) in 351 patients. Follow-up was completed in 335 patients and annualized MACE (cardiac death, myocardial infarction, revascularization, or hospitalization for congestive heart failure or de novo stable angor) rates were analysed with the Kaplan-Meier method in 318 patients after excluding 17 patients with early revascularizations (<60 days). Independent predictors of MACEs were identified by multivariate analysis. During a median follow-up of 624 days (inter-quartile range 540-697), 35 MACEs occurred. An annualized MACE rate was higher in patients with ischaemia (SDS >2) (n = 105) than those without [14% (95% CI = 9.1-22%) vs. 4.5% (2.7-7.4%), P < 0.0001]. The lowest MFR tertile group (MFR <1.8) had the highest MACE rate [16% (11-25%) vs. 2.9% (1.2-7.0%) and 4.3% (2.1-9.0%), P < 0.0001]. Similarly, the lowest stress MBF tertile group (MBF <1.8 mL/min/g) had the highest MACE rate [14% (9.2-22%) vs. 7.3% (4.2-13%) and 1.8% (0.6-5.5%), P = 0.0005]. Quantitation with stress MBF or MFR had a significant independent prognostic power in addition to semi-quantitative findings. The largest added value was conferred by combining stress MBF to SDS. This holds true even for patients without ischaemia. CONCLUSION: Perfusion findings in (82)Rb PET/CT are strong MACE outcome predictors. MBF quantification has an added value allowing further risk stratification in patients with normal and abnormal perfusion images.

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Report on a review of selected general and application controls for the Iowa Department of Education’s Electronic Access System for Iowa Education Records (EASIER) system for the period April 4 through May 10, 2011

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AIMS: Previous neuroimaging reports described morphological and functional abnormalities in anterior cingulate cortex (ACC) in schizophrenia and mood disorders. In earlier neuropathological studies, microvascular changes that could affect brain perfusion in these disorders have rarely been studied. Here, we analysed morphological parameters of capillaries in this area in elderly cases affected by these psychiatric disorders. METHODS: We analysed microvessel diameters in the dorsal and subgenual parts of the ACC in eight patients with schizophrenia, 10 patients with sporadic bipolar disorder, eight patients with sporadic major depression, and seven age- and gender-matched control cases on sections stained with modified Gallyas silver impregnation using a stereological counting approach. All individuals were drug-naïve or had received psychotropic medication for less than 6 months, and had no history of substance abuse. Statistical analysis included Kruskal-Wallis group comparisons with Bonferroni correction as well as multivariate regression models. RESULTS: Mean capillary diameter was significantly decreased in the dorsal and subgenual parts of areas 24 in bipolar and unipolar depression cases, both in layers III and V, whereas schizophrenia patients were comparable with controls. These differences persisted when controlling for age, local neuronal densities, and cortical thickness. In addition, cortical thickness was significantly smaller in both layers in schizophrenia patients. CONCLUSIONS: Our findings indicate that capillary diameters in bipolar and unipolar depression but not in schizophrenia are reduced in ACC. The significance of these findings is discussed in the light of the cytoarchitecture, brain metabolism and perfusion changes observed in ACC in mood disorders.

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Nonlocal approximations for the electronic exchange and correlation effects are used to compute, within density-functional theory, the polarizability and surface-plasma frequencies of small jelliumlike alkali-metal clusters. The results are compared with those obtained using the local-density approximation and with available experimental data, showing the relevance of these effects in obtaining an accurate description of the surface response of metallic clusters.

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Alzheimer's disease (AD) disrupts functional connectivity in distributed cortical networks. We analyzed changes in the S-estimator, a measure of multivariate intraregional synchronization, in electroencephalogram (EEG) source space in 15 mild AD patients versus 15 age-matched controls to evaluate its potential as a marker of AD progression. All participants underwent 2 clinical evaluations and 2 EEG recording sessions on diagnosis and after a year. The main effect of AD was hyposynchronization in the medial temporal and frontal regions and relative hypersynchronization in posterior cingulate, precuneus, cuneus, and parietotemporal cortices. However, the S-estimator did not change over time in either group. This result motivated an analysis of rapidly progressing AD versus slow-progressing patients. Rapidly progressing AD patients showed a significant reduction in synchronization with time, manifest in left frontotemporal cortex. Thus, the evolution of source EEG synchronization over time is correlated with the rate of disease progression and should be considered as a cost-effective AD biomarker.