932 resultados para Spinning disc atomizer
Resumo:
Pós-graduação em Ciência dos Materiais - FEIS
Resumo:
Pós-graduação em Ciência dos Materiais - FEIS
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
BACKGROUND CONTEXT: The relationships between obesity and low back pain (LBP) and lumbar disc degeneration (LDD) remain unclear. It is possible that familial factors, including genetics and early environment, affect these relationships.PURPOSE: To investigate the relationship between obesity-related measures (eg, weight, body mass index [BMI]) and LBP and LDD using twin studies, where the effect of genetics and early environment can be controlled.STUDY DESIGN: A systematic review with meta-analysis.METHODS: MEDLINE, CINAHL, Scopus, Web of Science, and EMBASE databases were searched from the earliest records to August 2014. All cross-sectional and longitudinal observational twin studies identified by the search strategy were considered for inclusion. Two investigators independently assessed the eligibility, conducted the quality assessment, and extracted the data. Metaanalyses (fixed or random effects, as appropriate) were used to pool studies'estimates of association.RESULTS: In total, 11 articles met the inclusion criteria. Five studies were included in the LBP analysis and seven in the LDD analysis. For the LBP analysis, pooling of the five studies showed that the risk of having LBP for individuals with the highest levels of BMI or weight was almost twice that of people with a lower BMI (odds ratio [OR] 1.8; 95% confidence interval [CI] 1.6-2.0; I-2 = 0%). A dose-response relationship was also identified. When genetics and the effects of a shared early environment were adjusted for using a within-pair twin case-control analysis, pooling of three studies showed a reduced but statistically positive association between obesity and prevalence of LBP (OR 1.5; 95% CI 1.1-2.1; I-2 = 0%). However, the association was further diminished and not significant (OR 1.4; 95% CI 0.8-2.3; I-2 = 0%) when pooling included two studies on monozygotic twin pairs only. Seven studies met the inclusion criteria for LDD. When familial factors were not controlled for, body weight was positively associated with LDD in all five cross-sectional studies. Only two cross-sectional studies investigated the relationship between obesity-related measures and LDD accounting for familial factors, and the results were conflicting. One longitudinal study in LBP and three longitudinal studies in LDD found no increase in risk in obese individuals, whether or not familial factors were controlled for.CONCLUSIONS: Findings from this review suggest that genetics and early environment are possible mechanisms underlying the relationship between obesity and LBP; however, a direct causal link between these conditions appears to be weak. Further longitudinal studies using the twin design are needed to better understand the complex mechanisms underlying the associations between obesity, LBP, and LDD.
Resumo:
Human activities are altering the concentrations of ozone in the troposphere and hence in the incidence of ultraviolet-B (UV-B) on Earth’s surface. Although representing only five percent of UV-B radiation striking the Earth's surface, this radiation has the potential to cause effects on biologically active molecules. Sensitivity to UV-B radiation is one of the limitations of biological control of plant pathogens in the field. The objectives of this work were to evaluate the effects of UV-B on several isolates of Clonostachys rosea, and the ability of an isolate of C. rosea, previously selected for its tolerant to UV-B radiation, to control Botrytis cinerea on strawberry leaves in controlled conditions (strawberry leaf discs). The germination of C. rosea conidia was inversely proportional to the irradiance. The most tolerant strain (LQC62) had relative germination of about 60% after irradiation of 4.2kJ/m2, and this strain was selected to be used in the subsequent studies. The data showed that even with exposure to UV-B radiation, C. rosea LQC62 controlled the pathogen. Conidial concentrations of strain LQC62 above 105 conidia/ml showed higher tolerance to UV-B radiation and increased ability to control more than 75% of the B. cinerea even with exposure to radiation. According to our results, in addition to showing less growth under UV-B, conidia of C. rosea had lower antagonistic ability. Further studies are needed to observe the tolerance of B. cinerea conidia to UV-B radiation and thereby prove that an environment with increased UV-B radiation may be favoring the pathogen due to a lower ability of C. rosea to control the pathogen in conditions of increased UV-B.
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
In this article, we study the Reidemeister torsion and the analytic torsion of the m dimensional disc, with the Ray and Singer homology basis (Adv Math 7:145-210, 1971). We prove that the Reidemeister torsion coincides with a power of the volume of the disc. We study the additional terms arising in the analytic torsion due to the boundary, using generalizations of the Cheeger-Muller theorem. We use a formula proved by Bruning and Ma (GAFA 16:767-873, 2006) that predicts a new anomaly boundary term beside the known term proportional to the Euler characteristic of the boundary (Luck, J Diff Geom 37:263-322, 1993). Some of our results extend to the case of the cone over a sphere, in particular we evaluate directly the analytic torsion for a cone over the circle and over the two sphere. We compare the results obtained in the low dimensional cases. We also consider a different formula for the boundary term given by Dai and Fang (Asian J Math 4:695-714, 2000), and we compare the results. The results of these work were announced in the study of Hartmann et al. (BUMI 2:529-533, 2009).
Resumo:
PURPOSE. We previously demonstrated that most eyes have regionally variable extensions of Bruch's membrane (BM) inside the clinically identified disc margin (DM) that are clinically and photographically invisible. We studied the impact of these findings on DM- and BM opening (BMO)-derived neuroretinal rim parameters. METHODS. Disc stereo-photography and spectral domain optical coherence tomography (SD-OCT, 24 radial B-scans centered on the optic nerve head) were performed on 30 glaucoma patients and 10 age-matched controls. Photographs were colocalized to SD-OCT data such that the DM and BMO could be visualized in each B-scan. Three parameters were computed: (1) DM-horizontal rim width (HRW), the distance between the DM and internal limiting membrane (ILM) along the DM reference plane; (2) BMO-HRW, the distance between BMO and ILM along the BMO reference plane; and (3) BMO-minimum rim width (MRW), the minimum distance between BMO and ILM. Rank-order correlations of sectors ranked by rim width and spatial concordance measured as angular distances between equivalently ranked sectors were derived. RESULTS. The average DM position was external to BMO in all quadrants, except inferotemporally. There were significant sectoral differences among all three rim parameters. DM- HRW and BMO-HRW sector ranks were better correlated (median rho = 0.84) than DM- HRW and BMO-MRW (median rho = 0.55), or BMO-HRW and BMO-MRW (median rho = 0.60) ranks. Sectors with the narrowest BMO-MRW were infrequently the same as those with the narrowest DM-HRW or BMO-HRW. CONCLUSIONS. BMO-MRW quantifies the neuroretinal rim from a true anatomical outer border and accounts for its variable trajectory at the point of measurement. (Invest Ophthalmol Vis Sci. 2012;53:1852-1860) DOI:10.1167/iovs.11-9309
Resumo:
Objectives: The aim of this study was to investigate bone changes in the condyle, articular eminence and glenoid fossa in relation to the position of the articular disc. Methods: 148 temporomandibular joints (TMJs) of 74 symptomatic patients who underwent MRI were evaluated. The position of the disc was classified as either normal (N), disc displacement with reduction (DDwR), disc displacement without reduction (DDwoR) and posterior displacement (PD). Bone changes were investigated in the condyle and temporal components of the TMJ and classified as osteophytosis, sclerosis or erosion. Results: There were no bone changes in the glenoid fossa of the temporal bone. Of the total number of TMJs studied, 94 (63.5%) were N, 34 (23%) presented DDwoR, 19 (12.8%) presented DDwR and 1 (0.7%) presented PD. The bone changes in the condyle and posterior aspect of the articular eminence were associated with the position of the disc. The bone changes in the anterior aspect of the articular eminence were not associated with the position of the disc. Conclusion: In cases of DDwoR, bone changes in the condyles were more common. The combination of erosion and osteophytosis in the condyle and the bone changes of the posterior aspect of the articular eminence were associated with disc position. Dentomaxillofacial Radiology (2012) 41, 367-372. doi: 10.1259/dmfr/79317853
Resumo:
Objective: To characterize optic nerve head (ONH) anatomy related to the clinical optic disc margin with spectral domain-optical coherence tomography (SD-OCT). Design: Cross-sectional study. Participants: Patients with open-angle glaucoma with focal, diffuse, and sclerotic optic disc damage, and age-matched normal controls. Methods: High-resolution radial SD-OCT B-scans centered on the ONH were analyzed at each clock hour. For each scan, the border tissue of Elschnig was classified for obliqueness (internally oblique, externally oblique, or nonoblique) and the presence of Bruch's membrane overhanging the border tissue. Optic disc stereophotographs were co-localized to SD-OCT data with customized software. The frequency with which the disc margin identified in stereophotographs coincided with (1) Bruch's membrane opening (BMO), defined as the innermost edge of Bruch's membrane; (2) Bruch's membrane/border tissue, defined as any aspect of either outside BMO or border tissue; or (3) border tissue, defined as any aspect of border tissue alone, in the B-scans was computed at each clock hour. Main Outcome Measures: The SD-OCT structures coinciding with the disc margin in stereophotographs. Results: There were 30 patients (10 with each type of disc damage) and 10 controls, with a median (range) age of 68.1 (42-86) years and 63.5 (42-77) years, respectively. Although 28 patients (93%) had 2 or more border tissue configurations, the most predominant one was internally oblique, primarily superiorly and nasally, frequently with Bruch's membrane overhang. Externally oblique border tissue was less frequent, observed mostly inferiorly and temporally. In controls, there was predominantly internally oblique configuration around the disc. Although the configurations were not statistically different between patients and controls, they were among the 3 glaucoma groups. At most locations, the SD-OCT structure most frequently identified as the disc margin was some aspect of Bruch's membrane and border tissue external to BMO. Bruch's membrane overhang was regionally present in the majority of patients with glaucoma and controls; however, in most cases it was not visible as the disc margin. Conclusions: The clinically perceived disc margin is most likely not the innermost edge of Bruch's membrane detected by SD-OCT. These findings have important implications for the automated detection of the disc margin and estimates of the neuroretinal rim. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. Ophthalmology 2012;119:738-747 (C) 2012 by the American Academy of Ophthalmology.
Resumo:
Purpose: To investigate the rate of visual field and optic disc change in patients with distinct patterns of glaucomatous optic disc damage. Design: Prospective longitudinal study. Participants: A total of 131 patients with open-angle glaucoma with focal (n = 45), diffuse (n = 42), and sclerotic (n = 44) optic disc damage. Methods: Patients were examined every 4 months with standard automated perimetry (SAP, SITA Standard, 24-2 test, Humphrey Field Analyzer, Carl Zeiss Meditec, Dublin, CA) and confocal scanning laser tomography (CSLT, Heidelberg Retina Tomograph, Heidelberg Engineering GmbH, Heidelberg, Germany) for a period of 4 years. During this time, patients were treated according to a predefined protocol to achieve a target intraocular pressure (IOP). Rates of change were estimated by robust linear regression of visual field mean deviation (MD) and global optic disc neuroretinal rim area with follow-up time. Main Outcome Measures: Rates of change in MD and rim area. Results: Rates of visual field change in patients with focal optic disc damage (mean -0.34, standard deviation [SD] 0.69 dB/year) were faster than in patients with sclerotic (mean - 0.14, SD 0.77 dB/year) and diffuse (mean + 0.01, SD 0.37 dB/year) optic disc damage (P = 0.003, Kruskal-Wallis). Rates of optic disc change in patients with focal optic disc damage (mean - 11.70, SD 25.5 x 10(-3) mm(2)/year) were faster than in patients with diffuse (mean -9.16, SD 14.9 x 10(-3) mm(2)/year) and sclerotic (mean -0.45, SD 20.6 x 10(-3) mm(2)/year) optic disc damage, although the differences were not statistically significant (P = 0.11). Absolute IOP reduction from untreated levels was similar among the groups (P = 0.59). Conclusions: Patients with focal optic disc damage had faster rates of visual field change and a tendency toward faster rates of optic disc deterioration when compared with patients with diffuse and sclerotic optic disc damage, despite similar IOP reductions during follow-up. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. Ophthalmology 2012; 119: 294-303 (C) 2012 by the American Academy of Ophthalmology.