Amine-modified Carbon Aerogels for CO2 Capture

Ten different amines of different molar mass and structure were deposited from aqueous and methanolic solutions of different concentrations onto two types of carbon aerogel. Thermogravimetric analysis (TGA) was used to quantify the loading, thermal stability and CO2 capture capacity of the materials. Our results show that the amount of amine deposited did not depend on the solvent used, but was generally greater from more concentrated solutions, and increased with increasing molar mass. Deposition of amines was principally achieved by adsorption onto the mesopore walls, but without complete pore filling, and also, in some cases, by adsorption in the aerogel micropores. It was also concluded that the thermal stability of the amines deposited on the walls of the mesopores was independent of the solvent used, concentration or aerogel type. Preliminary studies of CO2 adsorption-desorption were carried out and a good correlation between ln(Cn) and 1/T, where Cn is the capacity at temperature T, was found. This enabled direct comparison to be made with published results obtained at different temperatures, and it was found that those obtained in this work were highly comparable with others found for amine-impregnated porous materials with similar amine loadings

Carbon aerogels used in carbon dioxide capture

In this work the maximum carbon dioxide adsorption capacity of carbon aerogels, obtained by a sol-gel process using 2,4-dihydroxybenzoic acid/formaldehyde (DHBAF) and resorcinol/formaldehyde (RF) as precursors, was studied. The effect of increasing the temperature of carbonization and physical activation of the samples DHBAF was also studied. The results showed that the maximum adsorption capacity is favoured at lower temperatures, adsorption and desorption are rapid and the performance is maintained over several cycles of CO2 adsorption/desorption. A comparison with samples of commercial carbons was also made and it was concluded that carbon aerogels exhibit a behaviour comparable or superior to that obtained for the commercial carbons studied

Implantable Sensor System for Remote Detection of a Restenosis Condition

Part 7: Perceptional SystemsInternational audienceThe increase of life expectancy in the European Union, and the high risk of cardiovascular diseases associated with age, are some of the main factors to contribute to the rise of healthcare costs. An intelligent stent (e-stent), capable of obtaining and transmitting real-time measurements of physiological parameters for its clinical consultation, can be a useful tool for long-term monitoring, diagnostic, and early warning system for arterial blockage without patient hospitalization. In this paper, a behavioural model of capacitive Micro-Electro-Mechanical (MEMS) pressure sensor is proposed and simulated under several restenosis conditions. Special attention has been given to the need of an accurate fault model, obtained from realistic finite-element simulations,to ensure long-term reliability; particularly for those faults whose behavior cannot be easily described by an analytical model

Abscesso tuberculoso cerebral em paciente com AIDS: relato de caso e revisão da literatura

Tuberculous brain abscesses in AIDS patients are considered rare with only eight cases reported in the literature. We describe the case of a 34-year-old woman with AIDS and previous toxoplasmic encephalitis who was admitted due to headache and seizures. A brain computed tomography scan disclosed a frontal hypodense lesion with a contrast ring enhancement. Brain abscess was suspected and she underwent a lesion puncture through a trepanation. The material extracted was purulent and the acid-fast smear was markedly positive. Timely medical and surgical approaches allowed a good outcome. Tuberculous abscesses should be considered in the differential diagnosis of focal brain lesions in AIDS patients. Surgical excision or stereotactic aspiration, and antituberculous treatment are the mainstay in the management of these uncommon lesions.Os abscessos tuberculosos cerebrais em pacientes com aids são raros, existindo apenas 8 casos publicados. Os autores relatam o caso de uma paciente de 34 anos com aids e antecedente de toxoplasmose cerebral, que foi admitida por cefaléia e convulsões. A tomografia computadorizada de crânio evidenciou lesão frontal única, grande, com realce anular e efeito expansivo. Diante da suspeita de abscesso cerebral foi submetida a trepanação, drenando material purulento e demonstrando presença de abundantes bacilos ácido-álcool resistentes. Abordagem cirúrgica e clínica oportuna determinaram uma boa evolução. Os abscessos tuberculosos devem ser considerados no diagnóstico diferencial das massas intracranianas em pacientes com aids. Excisão cirúrgica ou aspiração por estereotaxia e tuberculostáticos constituem as bases do tratamento destas lesões incomuns

AVALIAÇÃO E EFETIVIDADE DA ANALGESIA EM PESSOAS SUBMETIDAS A HEMODIÁLISE

Objetivo: Avaliar a prevalência de dor crónica e dor intradialítica em pessoas em programa hemodiálise, bem como a eficácia da terapia analgésica. Métodos: Estudo transversal e correlacional. Uma amostra aleatória composta por 183 pessoas submetidos a hemodiálise em duas clínicas e um serviço de nefrologia na região de Lisboa, Portugal. Aplicados Brief Pain Inventory, que analisa a influência da dor na vida da pessoa e Escala Visual Analógica para avaliar a dor intradialítica. Resultados: A amostra foi constituída em sua maioria por homens (59,6%) de nacionalidade portuguesa (78,7%), média de idade de 59,17 anos (± 14,64). A dor crónica ocorre em 56,6% das pessoas e a dor intradialítica em 30,1%. As causas da dor crónica foram musculoesqueléticas (68,7%) e dor associada ao acesso vascular (17,2%). A localização nos membros inferiores foi a mais comum (43,4%). O uso de analgésicos para dor crónica foi elevado (58,2%) e foram ainda utilizados o repouso (24,1%) e massagem/relaxamento (6,3%). O alívio da dor crónica verificou-se em 63% das pessoas, referindo alívio de mais de 50%. Conclusões: A dor de origem musculoesquelética é um sintoma frequente nesta amostra. A utilização de fármacos na gestão da dor crónica foi a estratégia mais aplicada

Spin-orbit coupling and intrinsic spin mixing in quantum dots

Spin-orbit coupling effects are studied in quantum dots in InSb, a narrow-gap material. Competition between different Rashba and Dresselhaus terms is shown to produce wholesale changes in the spectrum. The large (and negative) $g$-factor and the Rashba field produce states where spin is no longer a good quantum number and intrinsic flips occur at moderate magnetic fields. For dots with two electrons, a singlet-triplet mixing occurs in the ground state, with observable signatures in intraband FIR absorption, and possible importance in quantum computation.Comment: REVTEX4 text with 3 figures (high resolution figs available by request). Submitted to PR