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1.
OBJECTIVE: To determine whether maintenance therapy can be discontinued safety in patients with quiescent cytomegalovirus retinitis (CMVR) and increased CD4+ counts after treatment with highly active antiretroviral therapy (HAART). DESIGN: A prospective observational case series. PARTICIPANTS: Eight human immunodeficiency virus (HIV)-positive patients with quiescent CMVR who were taking HAART and had CD4+ counts above 100 cells/microliter elected to discontinue anti-CMV maintenance treatment. INTERVENTION: Biweekly-to-monthly indirect ophthalmoscopy and fundus photographs, monthly-to-quarterly CD4+ counts, and quarterly HIV viral loads were ordered. MAIN OUTCOME MEASURES: Twelve previously affected eyes were examined for evidence of recurrent retinitis, which was defined as any retinal whitening, border opacification, or expansion of areas of retinal pigment epithelial (RPE) atrophy greater than 750 microns. Four previously unaffected fellow eyes were observed for new CMVR. RESULTS: There was no reactivation or progression of retinitis in any patient during the mean follow-up interval of 11.4 months (range, 3-16 months). No previously unaffected eye developed CMVR. CD4+ remained elevated in all patients (range, 70-725; mean, 255). The HIV viral load ranged from undetectable to 139,000 copies. CONCLUSION: Discontinuation of maintenance therapy may be considered in patients with HAART-induced elevated CD4+ counts above 100 cells/microliter, prolonged relapse-free intervals during the reconstitution period before CD4+ counts rise above 100 cells/microliter, and completely quiescent retinitis characterized by RPE scarring only. Reduced risks of drug toxicity and drug-resistant organisms are potential benefits. Close observation for evidence of recurrent retinitis is indicated. 相似文献
2.
Marjan Marinek Jana Padenik Gomilek Iztok Aron Miran eh Alojz Kodre Jadran Maek 《Journal of the American Ceramic Society》2007,90(10):3274-3281
Yttria-stabilized zirconia (NiO/YSZ) composites were prepared by the modified citrate–nitrate combustion synthesis. The citrate–nitrate combustion proceeded through several consecutive steps. Evolution of structure in the system and its changes were followed up by thermogravimetry-differential scanning calorimetry, X-ray powder diffraction, extended X-ray absorption fine structure, and high resolution transmission electron microscopy analyses of intermediate products prepared at distinct temperatures that correspond to different stages of the combustion process. It was shown that the crystalline structure developed gradually, first with crystallization of nano-sized NiO particles (400°–700°C), which was followed by crystallization of YSZ (800°–900°C). The final composite material after heat treatment at 1100°C comprised of nano-crystals with an average size of 6.5±2 nm. 相似文献
3.
A model-based approach to reconstruction of 3D human arm motion from a monocular image sequence taken under orthographic
projection is presented. The reconstruction is divided into two stages. First, a 2D shape model is used to track the arm silhouettes
and second-order curves are used to model the arm based on an iteratively reweighted least square method. As a result, 2D
stick figures are extracted. In the second stage, the stick figures are backprojected into the scene. 3D postures are reconstructed
using the constraints of a 3D kinematic model of the human arm. The motion of the arm is then derived as a transition between
the arm postures. Applications of these results are foreseen in the analysis of human motion patterns.
Received: 26 January 1996 / Accepted: 17 July 1997 相似文献
4.
Gabriela Guevara-Carrion Jadran Vrabec Hans Hasse 《International Journal of Thermophysics》2012,33(3):449-468
Transport properties of ammonia and of the binary mixture ammonia + methanol are predicted for a broad range of liquid states
by molecular dynamics (MD) simulation on the basis of rigid, non-polarizable molecular models of the united-atom type. These
models were parameterized in preceding work using only experimental vapor-liquid equilibrium data. The self- and the Maxwell-Stefan
(MS) diffusion coefficients as well as the shear viscosity are obtained by equilibrium MD and the Green-Kubo formalism. Non-equilibrium
MD is used for the thermal conductivity. The transport properties of liquid ammonia are predicted for temperatures between
223 K and 473 K up to pressures of 200 MPa and are compared to experimental data and correlations thereof. Generally, good
agreement is achieved. The predicted self-diffusion coefficient as well as the shear viscosity deviates on average by less
than 15 % from the experiment and the thermal conductivity by less than 6 %. Furthermore, the self- and the MS transport diffusion
coefficients as well as the shear viscosity of the liquid mixture ammonia + methanol are studied at different compositions
and compared to the available experimental data. 相似文献
5.
For the design and optimization of CO2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry’s law constants, are proposed for the ternary mixture N2 + O2 + CO2. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry’s law constants of N2 and O2 in CO2 are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry’s law constants, is developed to reliably describe the VLE in the CO2-rich region. 相似文献
6.
Self-diffusion coefficients and binary Maxwell–Stefan diffusion coefficients were determined by equilibrium molecular dynamics simulations with the Green–Kubo method. The study covers five pure fluids: neon, argon, krypton, xenon, and methane and three binary mixtures: argon+krypton, argon+xenon, and krypton+xenon. The fluids are modeled by spherical Lennard-Jones pair-potentials, with parameters which were determined solely on the basis of vapor-liquid equilibrium data. The predictions of the self-diffusion coefficients agree within 5% for gas state points and about 10% for liquid state points. The Maxwell–Stefan diffusion coefficients are predicted within 10%. A test of Darken's model shows good agreement. 相似文献
7.
Jadran Vrabec Martin Bernreuther Hans‐Joachim Bungartz Wei‐Lin Chen Wilfried Cordes Robin Fingerhut Colin W. Glass Jürgen Gmehling René Hamburger Manfred Heilig Matthias Heinen Martin T. Horsch Chieh‐Ming Hsieh Marco Hülsmann Philip Jäger Peter Klein Sandra Knauer Thorsten Köddermann Andreas Köster Kai Langenbach Shiang‐Tai Lin Philipp Neumann Jürgen Rarey Dirk Reith Gábor Rutkai Michael Schappals Martin Schenk Andre Schedemann Mandes Schönherr Steffen Seckler Simon Stephan Katrin Stöbener Nikola Tchipev Amer Wafai Stephan Werth Hans Hasse 《化学,工程师,技术》2018,90(3):295-306
This article outlines advances in molecular modeling and simulation using massively parallel high‐performance computers (HPC). In the SkaSim project, partners from the HPC community collaborated with users from science and industry. The aim was to optimize the prediction of thermodynamic property data in terms of efficiency, quality and reliability using HPC methods. In this context, various topics were dealt with: atomistic simulation of homogeneous gas bubble formation, surface tension of classical fluids and ionic liquids, multicriteria optimization of molecular models, the development of the molecular simulation codes ls1 mardyn and ms2, atomistic simulation of gas separation processes, molecular membrane structure generators, transport resistors and the evaluation of predictive property data models based on specific mixture types. 相似文献
8.
Total mercury,methylmercury and selenium in mercury polluted areas in the province Guizhou,China 总被引:49,自引:0,他引:49
Horvat M Nolde N Fajon V Jereb V Logar M Lojen S Jacimovic R Falnoga I Liya Q Faganeli J Drobne D 《The Science of the total environment》2003,304(1-3):231-256
The province of Guizhou in Southwestern China is currently one of the world's most important mercury production areas. Emissions of mercury from the province to the global atmosphere have been estimated to be approximately 12% of the world total anthropogenic emissions. The main objective of this study was to assess the level of contamination with Hg in two geographical areas of Guizhou province. Mercury pollution in the areas concerned originates from mercury mining and ore processing in the area of Wanshan, while in the area of Quingzhen mercury pollution originates from the chemical industry discharging Hg through wastewaters and emissions to the atmosphere due to coal burning for electricity production. The results of this study confirmed high contamination with Hg in soil, sediments and rice in the Hg mining area in Wanshan. High levels of Hg in soil and rice were also found in the vicinity of the chemical plant in Quingzhen. The concentrations of Hg decreased with distance from the main sources of pollution considerably. The general conclusion is that Hg contamination in Wanshan is geographically more widespread, due to deposition and scavenging of Hg from contaminated air and deposition on land. In Quingzhen Hg contamination of soil is very high close to the chemical plant but the levels reach background concentrations at a distance of several km. Even though the major source of Hg in both areas is inorganic Hg, it was observed that active transformation of inorganic Hg to organic Hg species (MeHg) takes place in water, sediments and soils. The concentration of Hg in rice grains can reach up to 569 microg/kg of total Hg of which 145 microg/kg was in MeHg form. The percentage of Hg as MeHg varied from 5 to 83%. The concentrations of selenium can reach up to 16 mg/kg in soil and up to 1 mg/g in rice. A correlation exists between the concentration of Se in soil and rice, indicating that a portion of Se is bioavailable to plants. No correlation between Hg and Se in rice was found. Exposure of the local population to Hg may occur due to inhalation of Hg present in air (in particular in Hg mining area) and consumption of Hg contaminated food (in particular rice and fish) and water. Comparison of intake through these different routes showed that the values of Hg considerably exceed the USA EPA Reference Concentration (RfC) for chronic Hg exposure (RfC is 0.0004 mg/m(3)) close to the emission sources. Intake of Hg through food consumption, particularly rice and fish, is also an important route of Hg exposure in study area. In general, it can be concluded that the population mostly at risk is located in the vicinity of smelting facilities, mining activities and close to the waste disposal sites in the wider area of Wanshan. In order to assess the real level of contamination in the local population, it is recommended that biomonitoring should be performed, including Hg and MeHg measurements in hair, blood and urine samples. 相似文献
9.
Tumor involvement or sacrifice of the vagus nerve at the level of the jugular foramen is a cause of significant morbidity in skull base surgery. Management of the resulting dysphagia and dysphonia has been significantly improved by the development of vocal cord medialization. However, rehabilitation of palatal paralysis with the resulting velopharyngeal incompetence has not been widely addressed. In an effort to alleviate the symptoms of hypernasality and nasal reflux, unilateral adhesion of the palate to the posterior wall of the nasopharynx is proposed. This report summarizes the operative approach and results in eight patients. Results have been favourable with no significant postoperative complications observed to date. 相似文献
10.