869 resultados para Physical-appearance-based bias.
Resumo:
The commercially available Jacobsen catalyst, Mn(salen), was occluded in hybrid polymeric membranes based on poly(dimethylsiloxane) (PDMS) and poly(vinyl alcohol) (PVA). The obtained systems were characterized by UV-vis spectroscopy and SEM techniques. The membranes were used as a catalytic barrier between two different phases: an organic substrate phase (cyclooctene or styrene) in the absence of solvent, and an aqueous solution of either t-BuOOH or H(2)O(2). Membranes containing different percentages of PVA were prepared, in order to modulate their hydrophilic/hydrophobic swelling properties. The occluded complex proved to be an efficient catalyst for the oxidation of alkenes. The new triphasic system containing a cheap and easily available catalyst allowed substrate oxidation and easy product separation using ""green"" oxidants. (C) 2010 Elsevier B.V. All rights reserved.
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Clinical applications of quantitative computed tomography (qCT) in patients with pulmonary opacifications are hindered by the radiation exposure and by the arduous manual image processing. We hypothesized that extrapolation from only ten thoracic CT sections will provide reliable information on the aeration of the entire lung. CTs of 72 patients with normal and 85 patients with opacified lungs were studied retrospectively. Volumes and masses of the lung and its differently aerated compartments were obtained from all CT sections. Then only the most cranial and caudal sections and a further eight evenly spaced sections between them were selected. The results from these ten sections were extrapolated to the entire lung. The agreement between both methods was assessed with Bland-Altman plots. Median (range) total lung volume and mass were 3,738 (1,311-6,768) ml and 957 (545-3,019) g, the corresponding bias (limits of agreement) were 26 (-42 to 95) ml and 8 (-21 to 38) g, respectively. The median volumes (range) of differently aerated compartments (percentage of total lung volume) were 1 (0-54)% for the nonaerated, 5 (1-44)% for the poorly aerated, 85 (28-98)% for the normally aerated, and 4 (0-48)% for the hyperaerated subvolume. The agreement between the extrapolated results and those from all CT sections was excellent. All bias values were below 1% of the total lung volume or mass, the limits of agreement never exceeded +/- 2%. The extrapolation method can reduce radiation exposure and shorten the time required for qCT analysis of lung aeration.
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To evaluate the usefulness of intraoral ultrasonography (IOUS) as a tool for predicting neck metastasis. Squamous cell carcinoma (SCC) of the tongue is aggressive and has a great propensity to metastasize to cervical lymph nodes. SCC of the oral cavity has a worse prognosis when associated with metastatic cervical nodes. Therefore, the metastatic potential of tongue carcinoma should be graded preoperatively to help determine the requirement for neck dissection. Nineteen patients (11 men, 8 women) between 36 and 79 years of age (mean age 60) with T1 to T4a TNM-stage tongue carcinomas were evaluated preoperatively with IOUS. Clinical and pathological TNM classifications were performed. The average tumor thicknesses measured using histological sections were significantly (p < 0.01) lower than those with IOUS (1.3 vs. 1.6 cm, respectively). A significant correlation was observed between the tumor thickness measured using ultrasonography and that measured using histological sections (pathology). Based on this greater accuracy, the cutoff point of tumor thickness based on IOUS evaluation for predicting neck metastasis was determined to be 1.8 cm. Some factors may influence neck metastasis. A knowledge of these would help to avoid unnecessary surgical intervention for N0 patients. The results of this study indicates that there is a significant correlation between neck metastasis and tumor thickness. Intraoral ultrasonography is useful tool for identifying tongue tumors and measuring their thickness, with the thickness measured by IOUS showing a very good correlation with histological measurements. Moreover, IOUS provides prognostic information prior to surgical treatment since tumor thickness can predict the chance of recognizing metastatic cervical nodes.
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Objective: This study assessed the effects of an aquatic respiratory exercise-based program in patients with fibromyalgia (FMS). Methods: Forty women, aged between 20 and 60 years, were randomly assigned into two groups of 20 patients: the aquatic respiratory exercise-based program (ARG) and the control group (CTL). The ARG group performed the exercise program for 1 h, four times a week, for 4 weeks which included: (i) warming-Lip; (ii) respiratory exercises, consisting of five different breathing patterns, along With upper, lower limbs and trunk movements (45 min); and (iii) relaxation exercises. Both groups were included in supervised recreational activities of 1 h, once a week, for 4 weeks. Questionnaires were applied before and after intervention to assess quality of life and functional capacity (SF-36, Fibromyalgia Impact Questionnaire [FIQ]), anxiety (Hamilton Anxiety Scale [HAS]), and quality of sleep (Pittsburg Sleep Quality Index [PSQI]). Number of tender points and pain (Visual Analogue Scale [VAS]) were also evaluated. Results: At baseline there was no difference between the two groups, including number of tender points and questionnaire responses. After intervention, the ARG group, compared with the CTL group, showed improvement in SF-36 scores (physical functioning P = 0.001, bodily pain 1) = 0.001, vitality P = 0.009, social functioning P = 0.001, emotional role P = 0.001), in FIQ (total score P = 0.049, work missed P = 0.036, fatigue P = 0.013, morning tiredness P = 0.007) plus in VAS-pain (P = 0.029), VAS-dyspnea (P = 0.04), anxiety (HAS P = 0.005) and quality of sleep (PSQI P = 0.004). Conclusions: The short-term aquatic respiratory exercise-based program improved pain, quality of life, functional capacity, anxiety and quality of sleep in patients with FMS and may be a relevant addition to the treatment of these patients.
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Compared with other specialties, the field of physical and rehabilitation medicine has not received the deserved recognition from clinicians and researchers in the scientific community. One of the reasons is the lack of sound evidence to support the traditional physical and rehabilitation medicine treatments. The best way to change this disadvantage is through a well conducted clinical research, such as standard placebo- or sham-controlled randomized clinical trials. Therefore, having placebo groups in clinical trials is essential to improve the level of evidence-based practice in physical and rehabilitation medicine that ultimately translates to better clinical care. To address the challenges for the use of placebo in physical and rehabilitation medicine and randomized clinical trials and to create useful recommendations, we convened a working group during the inaugural International Symposium in Placebo (February 2009, in Sao Paulo, Brazil) in which the following topics were discussed: (1) current status of randomized clinical trials in physical and rehabilitation medicine, (2) challenges for the use of placebo in physical and rehabilitation medicine, (3) bioethics, (4) use of placebo in acupuncture trials and for the treatment of low-back pain, (5) mechanisms of placebo, and (6) insights from other specialties. The current article represents the consensus report from the working group.
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Wastewater control at storage terminals of liquid chemical products in bulk is very difficult because of the variety of products handled in the facilities generating effluents of variable composition. The main objective of this work was to verify if the Vibrio fischeri acute toxicity test could be routinely included in the wastewater management of those facilities along with physical and chemical analysis in order to evaluate and improve the quality of the generated effluents. The study was performed in two phases before and after the implementation of better operational practices/treatment technologies. Chemical oxygen demand (COD) and toxicity of treated effluents did not correlate showing that effluents with low COD contain toxic substances and non-biodegradable organic matter, which may be not degraded when discharged into the aquatic environment. Segregation of influents or pre-treatment based on toxicity results and biodegradability index were implemented in the facilities generating significant improvements in the quality of final effluents with reduction of Biochemical oxygen demand (BOD) and toxicity. The integration of physical and chemical analysis with the V.fischeri toxicity test turned out to be an excellent tool for wastewater management in chemical terminals allowing rapid decision making for pollution control and prevention measures. Reuse of rain water was also proposed and when implemented by the facilities resulted in economical and environmental benefits. (C) 2010 Elsevier B.V. All rights reserved.
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The starch content of unripe mango Keitt is around 7% (FW), and it is converted to soluble sugars during the ripening of the detached fruit. Despite the importance of starch-to-soluble sugar metabolism for mango quality, little literature is found on this subject and none concerning the physical aspects of starch degradation. This manuscript presents some changes in the physical aspects of the starch granule during ripening, as analyzed by light microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). According to the analysis, unripe Keitt-mango-starch being spherical in shape and measuring around 15,mu m, has A-type X-ray diffraction pattern with a degree of crystallinity around 21% with slight changes after 8 days of ripening. AFM images of the surface of the granules showed ultra microstructures, which are in agreement with a blocklet-based organization of the granules. The AFM-contrast image of growing layers covering the granule showed fibril-like structures, having 20 nm in diameter, transversally connecting the layer to the granule. The appearance of the partially degraded granules and the pattern of degradation were similar to those observed as a result of amylase activity, suggesting a hydrolytic pathway for the degradation of starch from mango cultivar Keitt. These results provide clues to a better understanding of starch degradation in fruits.
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The aim of this study was to estimate the 1-year prevalence of migraine and the degree of the association of migraine with some sociodemographic characteristics of a representative sample of the adult population of Brazil. This was a cross-sectional, population-based study. Telephone interviews were conducted on 3848 people, aged 18-79 years, randomly selected from the 27 States of Brazil. The estimated 1-year gender- and age-adjusted prevalence of migraine was 15.2%. Migraine was 2.2 times more prevalent in women, 1.5 times more in subjects with > 11 years of education, 1.59 times more in subjects with income of < 5 Brazilian Minimum Wages per month, and 1.43 times more in those who do not do any physical exercise. The overall prevalence of migraine in Brazil is 15.2%. Migraine is significantly more prevalent in women, subjects with higher education, with lower income, and those who do not exercise regularly, independently of their body mass index.
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To estimate the 1-year prevalence of tension-type headache (TTH) and the degree of the association of TTH with some sociodemographic characteristics of a representative sample of the adult population of Brazil. This was an observational, cross-sectional, population-based study. We conducted telephone interviews on 3848 people, aged 18-79 years, randomly selected from the 27 states of Brazil. Trained lay interviewers administered the structured questionnaire. It included questions about the sociodemographic characteristics of the population, as well as questions about headache. The degree of the association was calculated through prevalence ratios, adjusted with Poisson regression by gender, age, years of education, marital status, household income, job status, body mass index (BMI), and physical exercise. The estimated 1-year gender- and-age-adjusted prevalence of TTH was 13.0% (95% CI: 11.8-14.2%); 15.4% in males and 9.5% in females. The prevalence of probable TTH was 22.6% (95% CI: 21.1-24.1%). Most (86.2%) subjects reported episodic TTH; 6.4% had chronic TTH. The prevalence was higher at 18-29 years of age (16.2%). TTH was 1.6 times more prevalent in men, and 1.54 times more in subjects with more than 11 years of education. There was no significant association of TTH with marital or job status, household income, BMI, and physical activity. This is the first nationwide epidemiological study of TTH in Brazil. The overall prevalence of TTH in Brazil is low, at 13%. TTH is significantly more prevalent in males and subjects with higher education level.
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Our long-term objective is to devise reliable methods to generate biological replacement teeth exhibiting the physical properties and functions of naturally formed human teeth. Previously, we demonstrated the successful use of tissue engineering approaches to generate small, bioengineered tooth crowns from harvested pig and rat postnatal dental stem cells (DSCs). To facilitate characterizations of human DSCs, we have developed a novel radiographic staging system to accurately correlate human third molar tooth developmental stage with anticipated harvested DSC yield. Our results demonstrated that DSC yields were higher in less developed teeth (Stages 1 and 2), and lower in more developed teeth (Stages 3, 4, and 5). The greatest cell yields and colony-forming units (CFUs) capability was obtained from Stages 1 and 2 tooth dental pulp. We conclude that radiographic developmental staging can be used to accurately assess the utility of harvested human teeth for future dental tissue engineering applications.
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Objectives. To assess the elastic modulus (EM), volumetric shrinkage (VS), and polymerization shrinkage stress (PSS) of experimental highly filled nanohybrid composites as a function of matrix composition, filler distribution, and density. Methods. One regular viscosity nanohybrid composite (Grandio, VOCO, Germany) and one flowable nanohybrid composite (Grandio Flow, VOCO) were tested as references along with six highly filled experimental nanohybrid composites (four Bis-GMA-based, one UDMA-based, and one Ormocer (R) -based). The experimental composites varied in filler size and density. EM values were obtained from the ""three-point bending"" load-displacement curve. VS was calculated with Archimedes` buoyancy principle. PSS was determined in 1-mm thick specimens placed between two (poly) methyl methacrylate rods (empty set = 6 mm) attached to an universal testing machine. Data were analyzed using oneway ANOVA, Tukey`s test (alpha = 0.05), and linear regression analyses. Results. The flowable composite exhibited the highest VS and PSS but lowest EM. The PSS was significantly lower with Ormocer. The EM was significantly higher among experimental composites with highest filler levels. No significant differences were found between all other experimental composites regarding VS and PSS. Filler density and size did not influence EM, VS, or PSS. Significance. Neither the filler configuration nor matrix composition in the investigated materials significantly influenced composite shrinkage and mechanical properties. The highest filled experimental composite seemed to increase EM by keeping VS and PSS low; however, matrix composition seemed to be the determinant factor for shrinkage and stress development. The Ormocer, with reduced PSS, deserves further investigation. Filler size and density did not influence the tested parameters. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
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Objective. The aim of this study was to evaluate the pH, calcium release, setting time, and solubility of two commercially available mineral trioxide aggregate (MTA) cements (white MTA Angelus and MTA Bio), and of three experimental cements (light-cured MTA, Portland cement with 20% bismuth oxide and 5% calcium sulfate, and an epoxy resin-based cement). Study design. For evaluation of pH and calcium ion release, polyethylene tubes with 1.0 mm internal diameter and 10.0 mm length were filled with the cements and immediately immersed in flasks containing 10 mL deionized water. After 3, 24, 72, and 168 hours, the tubes were removed and the water from the previous container was measured for its pH and calcium content with a pH meter and an atomic absorption spectrophotometer. For analysis of the setting time, Gilmore needles weighing 100 g and 456.5 g were used, in accordance with the American Society for Testing and Materials specification no. C266-03. Solubility of each cement was also tested. Results. All the cements were alkaline and released calcium ions, with a declining trend over time. After 3 hours, Portland cement + bismuth oxide and MTA Bio had the highest pH and light-cured MTA the lowest. After 1 week, MTA Bio had the highest pH and light-cured MTA and epoxy resin-based cement the lowest. Regarding calcium ion release, after 3 hours, Portland cement + bismuth oxide showed the highest release. After 1 week, MTA Bio had the highest. Epoxy resin-based cement and light-cured MTA had the lowest calcium release in all evaluation periods. Regarding setting times, white MTA Angelus and MTA Bio had the shortest, Portland cement + bismuth oxide had an intermediate setting time, and the epoxy resin-based cement had the longest. The materials that showed the lowest solubility values were the epoxy resin-based cement, Portland cement + bismuth oxide, and light-cured MTA. The highest solubility values were presented in white MTA Angelus and MTA Bio. Conclusions. The white MTA Angelus and MTA Bio had the shortest setting times, higher pH and calcium ion release, and the highest solubility. In contrast, the epoxy resin-based cement and light-cured MTA showed lower values of solubility, pH, and calcium ion release. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 110: 250-256)
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Y2O3 is a c-type rare earth oxide with a fluorite-related structure. This material has been used to refractory because of its high thermal stability and excellent resistance to hydration. In this study, the effective index was suggested in order to improve the electrolytic properties of Y2O3-based oxide. (CexY1-x)(2)O3+delta (x = 0.25 and 0.3) and [LaaSrbCe0.25Y(1-a-b)](2)O3+delta (a = 0.05, 0.1 and 0.15, b = 0, 0.006 and 0.0125) were prepared as the examples with intermediate and high index, respectively. The specimens with high index value such as (La0.15Ce0.25Y0.60)(2)O-3.25 and (La0.1Sr0.0125Ce0.25Y0.6375)(2)O-3.24 consisted of two phases such as c-type and fluorite, although (Ce0.25Y0.75)(2)O-3.25 with intermediate index value had a single phase of c-type rare earth oxide. Microanalysis indicates that a grain in the (La0.1Sr0.0125Ce0.25Y0.6375)(2)O-3.23(7) sintered body consists of c-type and fluorite phases. An interface between c-type and fluorite phases is coherent in a grain. This suggests that this effective index guides the crystal structure in the specimen to fluorite and the examined composition introduces the interface between c-type and fluorite in the microstructure. The electrochemical properties of specimens including Y2O3 were characterized on the basis of the suggested index. The electrical conductivity of Y2O3-based materials increased with an increase of the index. The apparent activation energy of Y2O3-based materials decreased with increasing index. The ionic transport number of oxygen of the specimens was improved by enhancement of the index, confirming validity of the index. The oxide ionic conductive region of (La0.1Sr0.0125Ce0.25Y0.(6375))(2)O-3.23(7) with high effective index extended up to P-O2 = 10(-18) atm at 800 degreesC, although the specimens with low or intermediate index showed p- or n-type semi-conduction in the same P-O2 region at 800 and 1000 degreesC. These results suggest that the interface between c-type and fluorite phases also contributes to improve the electrolytic properties in the grain. It is concluded that the improvement of electrolytic properties in Y2O3-based materials is attributable to the microstructure with interface between two phases in a grain and the fluorite structure guided by the suggested index. (C) 2001 Published by Elsevier Science B.V.