Lung segmentation in CT scans of patients with lower respiratory tract infection: influence of respiratory physiotherapy

The goal of the study was to assess the effects of a respiratory physiotherapy intervention in the tracheobronchial tree (TBT) volume and lung function in patients with lower respiratory tract infection (LRTI). In this framework, a method for TBT segmentation in Computer Tomography (CT) images of patients with LRTI was implemented, allowing to obtain volumetric data and study their correlation with the lung function (spirometry) parameterspublishe

Vortex and gap generation in gauge models of graphene

Effective quantum field theoretical continuum models for graphene are investigated. The models include a complex scalar field and a vector gauge field. Different gauge theories are considered and their gap patterns for the scalar, vector, and fermion excitations are investigated. Different gauge groups lead to different relations between the gaps, which can be used to experimentally distinguish the gauge theories. In this class of models the fermionic gap is a dynamic quantity. The finite-energy vortex solutions of the gauge models have the flux of the "magnetic field" quantized, making the Bohm-Aharonov effect active even when external electromagnetic fields are absent. The flux comes proportional to the scalar field angular momentum quantum number. The zero modes of the Dirac equation show that the gauge models considered here are compatible with fractionalization

Toxicidade crônica do difluberzuron sobre um invertebrado aquático bioindicador.

RESUMO: Nas ultimas décadas observa-se um crescimento considerável da aqüicultura como uma fonte alternativa na produção de alimentos. Entretanto, a saúde dos sistemas aquicolas e a qualidade dos seus efluentes se vê ameaçada pelo uso de agentes químicos empregados no controle de parasitas. Outra ameaça refere-se à aplicação de agroquímicos nas regiões de entorno, os quais podem atingir os sistemas aquícolas. Os organismos zooplanctônicos são responsáveis por 80% da produção secundaria nos ambientes aquáticos e de fundamental importância nos sistemas piscícolas. Portanto, alterações significativas sobre a comunidade zooplanctônica refletirão em desequilíbrio nesses ambientes. Um dos pesticidas mais utilizados hoje não só na aquicultura, mas também na agricultura é o diflubenzuron, usado no controle de exoparasitas de peixes. O presente trabalho visou o estudo de influência de concentrações subletais do pesticida no crescimento e sobrevivência do microcrustáceo zooplanctônico Daphnia similis, após um período de 7 dias de exposição. A maior concentração de efeito não observado (CENO) e a menor de efeito observado (CEO) foram respectivamente 0,033 e 0,11 ug L-1, tanto para a taxa de crescimento como para a sobrevivência. A concentração que afetou 50% da mobilidade dos organismos (CE50-7d) foi equivalente a 0,100 (0,073 ? 0,162) ug L-1, indicando que a toxicidade aumentou em aproximadamente 10 vezes em relação à exposição por 48 h. Os dados são úteis no estabelecimento de níveis máximos permissíveis em corpos de água e no manejo menos agressivo para a biota aquática quanto à aplicação do diflubenzuron

Experimentos como estratégia de aprendizagem de processos de oxidação-redução: uma análise da linguagem química

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Effects of N-functional groups on the electron transfer kinetics of VO²⁺/VO₂⁺ at carbon:Decoupling morphology from chemical effects using model systems

Carbons and nanocarbons are important electrode materials for vanadium redox flow battery applications, however, the kinetics of vanadium species are often sluggish at these surfaces, thus prompting interest in functionalization strategies to improve performance. Herein, we investigate the effect of N-functionalities on the VO2+/VO2+ redox process at carbon electrodes. We fabricate thin film carbon disk electrodes that are metal-free, possess well-defined geometry and display smooth topography, while featuring different N-site distribution, thus enabling a mechanistic investigation of the intrinsic surface activity towards VO2+/VO2+. Voltammetry and electrochemical impedance spectroscopy show that N-functionalities improve performance, with pyridinic/pyrrolic-N imparting the most significant improvements in charge transfer rates and reversibility, compared to graphitic-N. This was further supported by voltammetry studies on nitrogen-free electrodes modified via aryldiazonium chemistry with molecular pyridyl adlayers. Computational modeling using an electrochemical-chemical mechanism indicates that introduction of surface pyridinic/pyrrolic-N can increase the heterogeneous rate constants by approximately two orders of magnitude relative to those observed at nitrogen-free carbon (k0 = 1.29 × 10−4 vs 9.34 × 10−7 cm/s). Simulations also suggest that these N-functionalities play a role in affecting reaction rates in the chemical step. Our results indicate that nitrogen incorporation via basic functional groups offers an interesting route to the design of advanced carbon electrodes for VRFB devices.</p

Photoinduced intersubband transition in undoped HgCdTe multiple quantum wells

We present photoinduced intersubband absorption measurements in HgCdTe undoped quantum wells. The transition energies and the linewidths are well described by a full 8×8 k⋅p Kane model calculation. Also, based on this model we show that different in‐plane effective masses for the first and second electron subbands should be considered in order to properly fit the low energy side of the experimental spectra. The experimental results can be explained using the calculated intersubband oscillator strength with no exciton enhancement. © 1995 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69671/2/APPLAB-66-22-2998-1.pd