6957792 research outputs found
Sort by
Nano-Sim: A Step Wise Equivalent Conductance based Statistical Simulator for Nanotechnology Circuit Design
No full textAbstract: Ne
DMD055400 245..249
No full textABSTRACT Amlodipine is a commonly prescribed calcium channel blocker for the treatment of hypertension and ischemic heart disease. The drug is slowly cleared in humans primarily via dehydrogenation of its dihydropyridine moiety to a pyridine derivative (M9). Results from clinical drug-drug interaction studies suggest that CYP3A4/5 mediate metabolism of amlodipine. However, attempts to identify a role of CYP3A5 in amlodipine metabolism in humans based on its pharmacokinetic differences between CYP3A5 expressers and nonexpressers failed. Objectives of this study were to determine the metabolite profile of amlodipine (a racemic mixture and S-isomer) in human liver microsomes (HLM), and to identify the cytochrome P450 (P450) enzyme(s) involved in the M9 formation. Liquid chromatography/mass spectrometry analysis showed that amlodipine was mainly converted to M9 in HLM incubation. M9 underwent further O-demethylation, O-dealkylation, and oxidative deamination to various pyridine derivatives. This observation is consistent with amlodipine metabolism in humans. Incubations of amlodipine with HLM in the presence of selective P450 inhibitors showed that both ketoconazole (an inhibitor of CYP3A4/5) and CYP3cide (an inhibitor of CYP3A4) completely blocked the M9 formation, whereas chemical inhibitors of other P450 enzymes had little effect. Furthermore, metabolism of amlodipine in expressed human P450 enzymes showed that only CYP3A4 had significant activity in amlodipine dehydrogenation. Metabolite profiles and P450 reaction phenotyping data of a racemic mixture and S-isomer of amlodipine were very similar. The results from this study suggest that CYP3A4, rather than CYP3A5, plays a key role in metabolic clearance of amlodipine in humans
Case Report Preterm Caesarean Delivery in a Parturient with Candida parapsilosis Endocarditis
No full textWe present the first documented case of Candida parapsilosis infective endocarditis in a pregnant patient. While the incidence of infective endocarditis during pregnancy is rare, the incidence of C. parapsilosis endocarditis is even rarer. The numerous specific risks and decision making processes regarding this case are presented. Case Presentation A 23-year-old female, gravida 1, and para 0 at 31 weeks of gestation was transferred to our cardiothoracic intensive care unit (CTICU) for further management of her aortic valve endocarditis. Her past medical history included intravenous drug use (currently on methadone maintenance), hepatitis C discovered during this pregnancy, bipolar disorder, and depression with multiple prior suicide attempts. Of note, the patient also had a root canal two weeks prior and was started on ampicillin for a dental abscess. She initially presented to an outside hospital one week earlier with severe right thigh and groin pain, which had progressed to the point of inhibiting ambulation. A right lower extremity Doppler study revealed an occlusive thrombus in the deep femoral artery. She was started on therapeutic enoxaparin and transferred to a second hospital, where a transthoracic echocardiogram (TTE) revealed large vegetative lesions on all 3 leaflets of the aortic valve, including a mobile vegetation measuring 0.8-1-cm on the ventricular side of the valve Anticoagulation was withheld despite her thrombus due to concern for cerebral embolic infarction and risk of hemorrhagic conversion in the setting of mobile aortic endocarditis. A magnetic resonance angiogram (MRA) of the brain was obtained to rule out a mycotic aneurysm, given that her endocarditis was known to be fungal in nature. The MRA showed a 2.2 mm aneurysm of the anterior communicating artery. An ophthalmologic exam was negative for fungal endophthalmitis. She received betamethasone and magnesium sulfate for fetal lung maturity and fetal neuroprotection, respectively. A fetal ultrasound demonstrated normal growth and activity of the fetus. After a multidisciplinary meeting involving the CTICU intensivists, obstetrics, cardiothoracic surgery, cardiology, neurology, neurosurgery, obstetric anesthesiology, and obstetric and CTICU nursing teams, it was decided to proceed with delivery of the baby via Caesarean section followed by an aortic valve replacement (AVR) the following day. The decision to separate the procedures by approximately 12 hours was made out of concern for uterine bleeding after the Caesarean section with the full heparinization required for the AVR
Robust Adaptive Resource Allocation in Container Terminals
No full textABSTRACT. This paper considers adaptability for robust periodic capacity allocation problems, using the example of crane capacity allocation in container terminals. A new model is presented that allows to compute an adaptive plan via formulation of a linear program over a scenario graph. Computational results are given that quantify to the value of adaptability for reducing the price of robustness, i.e, the total capacity that is necessary to guarantee all service times for all considered realizations of the disturbances
Approximate Controllability of Semilinear Neutral Stochastic Integrodifferential Inclusions with Infinite Delay
No full textThe approximate controllability of semilinear neutral stochastic integrodifferential inclusions with infinite delay in an abstract space is studied. Sufficient conditions are established for the approximate controllability. The results are obtained by using the theory of analytic resolvent operator, the fractional power theory, and the theorem of nonlinear alternative for Kakutani maps. Finally, an example is provided to illustrate the theory
MHD Heat and Mass Transfer Free Convection Flow Near the Lower Stagnation Point of an Isothermal Cylinder Imbedded
No full textAbstract Heat and mass transfer characteristics and the flow behavior on MHD flow near the lower stagnation point of a porous isothermal horizontal circular cylinder have been studied. The equations of conservation of mass, momentum, energy and concentration which govern the case study of heat and mass transfer flow have been obtained. These equations have been transformed into a system of non-dimensional coupled non-linear ordinary differential equations by using similarity transformations and finally solved by Runge-Kutta and shooting method. It has been assumed that the fluid is incompressible, absorbing-emitting radiation and viscous, with temperature dependent viscosity and temperature dependent thermal conductivity in the presence of radiation. Velocity profiles, temperature distributions and concentration distributions for the flow have been presented for various values of radiation parameter, viscosity variation parameter, thermal conductivity variation parameter, Prandtl number and Schmidt number. The skin friction factor, local Nusselt number and Sherwood number are also calculated for all the parameters involved in the problem. It has been observed that with the increase in Schmidt number skin friction and Nusselt number decrease, while Sherwood number increases
Analytical Method Development and Validation for Simultaneous Estimation of Timolol Maleate and Brimonidine Tartrate in Bulk and Marketed Ophthalmic Formulation
No full textMaheta S et al 351 ABSTRACT: A new, simple, precise, accurate and sensitive High Performance Thin Layer Chromatographic method has been developed for the estimation of Timolol Maleate and Brimonidine Tartrate in bulk and marketed ophthalmic formulation. The determination was made at 268 nm for Timolol Maleate and Brimonidine Tartrate over the concentration range of 500-1500 ng/spot and 200-600 ng/spot respectively. The mean recovery of Timolol Maleate and Brimonidine Tartrate was found 99.40% and 99.14% respectively. The LOD was found to be 65.33 ng/spot and 48.20 ng/spot for Timolol Maleate and Brimonidine Tartrate respectively. The LOQ was found to be 197.97 ng/spot and 146.08 ng/spot for Timolol Maleate and Brimonidine Tartrate respectively. Chloroform: Methanol: Ammonia (30%) (9:1:0.1 v/v/v) was selected as a mobile phase. The validation of method was carried out as per ICH Guidelines
Cultural study; A new approach to educational studies
No full textAbstract In this article, the present researchers try to study cultural study approach in understanding educational phenomena. At the first step, we discuss the important backgrounds of this trend, and at the second step, the methodological factors of this trend are investigated. In this article, two research paradigms in educational study (positive approach and cultural study) are compared. Of course, aside from these two paradigms, we can draw the third paradigm which studies educational phenomena with hermeneutic trend. Our purpose is to draw and determine cultural study status among the abovementioned paradigms for studying educational phenomena
An environmental optimization model for bioenergy plant sizes and locations for the case of wood-derived SNG in Switzerland
Get PDFAbstract: Bioenergy from woodfuel has a considerable potential to substitute fossil fuels and alleviate global warming. One issue so far not systematically addressed is the question of the optimal size of bioenergy plants with regards to environmental and economic performance. The aim of this work is to fill this gap by modeling the entire production chain of wood and its conversion to bioenergy in a synthetic natural gas plant both with respect to economic and environmental performance. Several spatially explicit submodels for the availability, harvest, transportation and conversion of wood were built and joined in a multi-objective optimization model to determine optimal plant sizes for any desired weighting of environmental impacts and profits. We find a trade-off between environmental and economic optimal plant sizes. While the economic optima range between 75 -200 MW, the environmental optima are with 10 -40 MW significantly smaller. Moreover, the economic optima are highly location specific and tend to be smaller if the biomass resource in the geographic region of the plant is scarcer. The results are similar with regards to the effect on global warming as well as with respect to the aggregated environmental impact assessment methods Ecoindicator '99 and Ecological Scarcity 2006
Thermal phenomena in MBBA *
Get PDFAbstract We describe the phenomena observed in heating a thin film of mbba from room temperature through the nematic-to-isotropic phase transition temperature, including color changes, bright and dark bands, nucleation and growth, and nematic-isotropic interface propagation. Plausible explanations are offered as to the underlying physical processes