807 research outputs found
Caracterização climática do Município de São José de Ubá, Estado do Rio de Janeiro.
bitstream/CNPS-2010/14921/1/bpd95-2006-clima-sao-jose-uba.pd
Emergent cell-free layer asymmetry and biased haematocrit partition in a biomimetic vascular network of successive bifurcations
Blood is a vital soft matter, and its normal circulation in the human body relies on the distribution of red blood cells (RBCs) at successive bifurcations. Understanding how RBCs are partitioned at bifurcations is key for the optimisation of microfluidic devices as well as for devising novel strategies for diagnosis and treatment of blood-related diseases. We report the dynamics of RBC suspensions flowing through a biomimetic vascular network incorporating three generations of microchannels and two classical types of bifurcations at the arteriole level. Our microfluidic experiments with dilute and semidilute RBC suspensions demonstrate the emergence of excessive heterogeneity of RBC concentration in downstream generations upon altering the network's outflow rates. Through parallel simulations using the immersed-boundary-lattice-Boltzmann method, we reveal that the heterogeneity is attributed to upstream perturbations in the cell-free layer (CFL) and lack of its recovery between consecutive bifurcations owing to suppressed hydrodynamic lift under reduced flow conditions. In the dilute/semidilute regime, this perturbation dominates over the effect of local fractional flow at the bifurcation and can lead to inherently unfavourable child branches that are deprived of RBCs even for equal flow split. Our work highlights the importance of CFL asymmetry cascading down a vascular network, which leads to biased phase separation that deviates from established empirical predictions
The D1822V APC polymorphism interacts with fat, calcium, and fiber intakes in modulating the risk of colorectal cancer in Portuguese persons
Background - Both genetic and environmental factors affect the risk of colorectal cancer (CRC). Objective - We aimed to examine the interaction between the D1822V polymorphism of the APC gene and dietary intake in persons with CRC. Design - Persons with CRC (n = 196) and 200 healthy volunteers, matched for age and sex in a case-control study, were evaluated with respect to nutritional status and lifestyle factors and for the D1822V polymorphism. Results - No significant differences were observed in energy and macronutrient intakes. Cases had significantly (P < 0.05) lower intakes of carotenes, vitamins C and E, folate, and calcium than did controls. Fiber intake was significantly (P = 0.004) lower in cases than in controls, whereas alcohol consumption was associated with a 2-fold risk of CRC. In addition, cases were significantly (P = 0.001) more likely than were controls to be sedentary. The homozygous variant for the APC gene (VV) was found in 4.6% of cases and in 3.5% of controls. Examination of the potential interactions between diet and genotype found that a high cholesterol intake was associated with a greater risk of colorectal cancer only in noncarriers (DD) of the D1822V APC allele (odds ratio: 1.66; 95% CI: 1.00, 2.76). In contrast, high fiber and calcium intakes were more markedly associated with a lower risk of CRC in patients carrying the polymorphic allele (DV/VV) (odds ratio: 0.50; 95% CI: 0.27, 0.94 for fiber; odds ratio: 0.51; 95% CI: 0.28, 0.93 for calcium) than in those without that allele. Conclusion - These results suggest a significant interaction between the D1822V polymorphism and the dietary intakes of cholesterol, calcium, and fiber for CRC risk
Preservação e organização da geoinformação em instituições: o caso da construção da Infraestrutura de Dados Espaciais da Embrapa.
O objetivo deste trabalho é apresentar a estratégia da Embrapa para construir sua Infraestrutura de Dados Espaciais de forma a contribuir com o debate sobre a organização, preservação e integração de dados geoespaciais heterogêneos de acordo com as diretrizes federais estabelecidas pela INDE. Para esse fim, apresentaremos as etapas do processo interno realizado na Embrapa para elaboração o plano de adesão à INDE, o qual contou com a formação de um grupo de trabalho e, em seguida, descreveremos a estratégia elaborada
Phase-sensitive optical time domain reflectometer assisted by first-order raman amplification for distributed vibration sensing over >100 km
In this study, the authors present an experimental and theoretical description of the use of first order Raman amplification to improve the performance of a Phase-sensitive optical time domain reflectometer (φ OTDR) when used for vibration measurements over very long distances. A special emphasis is given to the noise which is carefully characterized and minimized along the setup. A semiconductor optical amplifier and an optical switch are used to greatly decrease the intra-band coherent noise of the setup and balanced detection is used to minimize the effects of RIN transferred from the Raman pumps. The sensor was able to detect vibrations of up to 250 Hz (close to the limits set by the time of flight of light pulses) with a resolution of 10 m in a range of 125 km. To achieve the above performance, no post-processing was required in the φOTDR signal. The evolution of the φOTDR signal along the fiber is also shown to have a good agreement with the theoretical model.European CommissionMinisterio de Economía y CompetitividadComunidad de Madri
Effect of inorganic fillers on the light transmission through traditional or flowable resin-matrix composites for restorative dentistry
Objectives: The aim of this in vitro study was to evaluate the light transmission through five different resin-matrix composites regarding the inorganic filler content. Methods: Resin-matrix composite disc-shaped specimens were prepared on glass molds. Three traditional resin-matrix composites contained inorganic fillers at 74, 80, and 89 wt. % while two flowable composites revealed 60 and 62.5 wt. % inorganic fillers. Light transmission through the resin-matrix composites was assessed using a spectrophotometer with an integrated monochromator before and after light curing for 10, 20, or 40s. Elastic modulus and nanohardness were evaluated through nanoindentation’s tests, while Vicker’s hardness was measured by micro-hardness assessment. Chemical analyses were performed by FTIR and EDS, while microstructural analysis was conducted by optical microscopy and scanning electron microscopy. Data were evaluated using two-way ANOVA and Tukey’s test (p < 0.05). Results: After polymerization, optical transmittance increased for all specimens above 650-nm wavelength irradiation since higher light exposure time leads to increased light transmittance. At 20- or 40-s irradiation, similar light transmittance was recorded for resin composites with 60, 62, 74, or 78–80 wt. % inorganic fillers. The lowest light transmittance was recorded for a resin-matrix composite reinforced with 89 wt. % inorganic fillers. Thus, the size of inorganic fillers ranged from nano- up to micro-scale dimensions and the high content of micro-scale inorganic particles can change the light pathway and decrease the light transmittance through the materials. At 850-nm wavelength, the average ratio between polymerized and non-polymerized specimens increased by 1.6 times for the resin composite with 89 wt. % fillers, while the composites with 60 wt. % fillers revealed an increased ratio by 3.5 times higher than that recorded at 600-nm wavelength. High mean values of elastic modulus, nano-hardness, and micro-hardness were recorded for the resin-matrix composites with the highest inorganic content. Conclusions: A high content of inorganic fillers at 89 wt.% decreased the light transmission through resin-matrix composites. However, certain types of fillers do not interfere on the light transmission, maintaining an optimal polymerization and the physical properties of the resin-matrix composites. Clinical significance: The type and content of inorganic fillers in the chemical composition of resin-matrix composites do affect their polymerization mode. As a consequence, the clinical performance of resin-matrix composites can be compromised, leading to variable physical properties and degradation. Graphical Abstract: [Figure not available: see fulltext.].info:eu-repo/semantics/publishedVersio
Estimativa da erosividade nas bacias hidrográficas dos rios Guapi-Macacu e Caceribu.
As perdas de solos ocasionadas por eventos de chuvas não dependem somente da resistência que o solo oferece ao impacto das gotas, mas também da energia cinética da chuva e da intensidade e duração. A influência desses fatores na capacidade da chuva em causar erosão é estimada através de índices de erosividade, sendo mais utilizados dois índices na literatura: EI30 e KE > 25. O presente trabalho teve como objetivo estimar os índices de erosividade com base nos dados pluviométricos de 19 estações e mostrar as distribuições espaciais dos mesmos nas bacias hidrográficas dos rios Guapi- Macacu e Caceribu. Os resultados mostraram que os dois índices apresentaram padrão similar em termos de valores relativos e de distribuição na área de estudo. Os índices apresentaram maiores valores mensais no período de novembro a março que corresponde ao verão, quando é característico ocorrerem chuvas de maiores intensidades, devido ao aumento da temperatura e das movimentações de massas de ar. Ao contrário, os menores valores foram observados nos meses de junho a agosto, período no qual ocorrem chuvas com menores intensidades.bitstream/item/83413/1/BPD-205-Estimativa-erosividade.pd
Association between Apical Periodontitis and Chronic Diseases: An Umbrella Review
Introduction: To assess the methodological quality of systematic reviews (SRs) that evaluated the association between apical periodontitis (AP) and chronic diseases. Materials and Methods: A systematic search was performed in the databases PubMed, Virtual Health Library, Scopus, Cochrane Library, Embase, Web of Science and Open Grey. SRs that evaluated the association between any chronic disease and AP, and that had performed a valid risk of bias assessment were included. The AMSTAR-2 tool was used for quality assessment and each included systematic review received a final categorization as having “high”, “moderate”, “low”, or “critically low” quality. Results: Nine studies that met the eligibility criteria were included. The diseases investigated were cardiovascular diseases, diabetes mellitus, HIV, osteoporosis, chronic liver disease, blood disorders and autoimmune diseases. The systematic reviews included in this umbrella review showed a ‘low’ to ‘high’ quality of evidence. Conclusion: There are substantial heterogeneity and several methodological concerns in the included studies. It was observed a positive association between diabetes mellitus and apical periodontitis with limited evidence, no association between HIV and apical periodontitis and a positive association between apical periodontitis and cardiovascular disease, blood disorders, chronic liver disease, osteoporosis and autoimmune diseases with moderate evidence
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