Simón Bolívar University

About: Simón Bolívar University is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Population & Crystallization. The organization has 5912 authors who have published 8294 publications receiving 126152 citations.

Adsorption of Water Vapor−Methane Mixtures on Activated Carbons

Abstract: We report grand canonical Monte Carlo simulation studies of adsorption for a molecular model of water and water vapor−methane mixtures on activated carbon pores For pure water, the influence of the density of oxygenated sites in the carbons, and of the strength of the water−site interaction is investigated It is shown that the site density has a profound influence on the adsorption at low and moderate pressures and that, except for very low site densities, capillary condensation does not occur The adsorption of water is very slight for water−site interaction strengths below eHB/k < 3000 K but rises rapidly above this value For water−methane mixtures, the adsorption behavior is also strongly dependent on the surface site density Even for very low site densities, for example, n ∼ 005 site/nm2, water clusters form around sites and block a significant fraction of the surface to methane adsorption This effect is significant for pores of width 20 nm For pores of width 10 nm, the effect is much larger,

Update on the impact of Chlamydia trachomatis infection on male fertility

Abstract: Summary With approximately 90 million cases annually, infection with Chlamydia trachomatis is the most prevalent sexually transmitted bacterial disease in the world Considering that these infections are often asymptomatic and cause major complications like acute pelvic inflammatory disease, ectopic pregnancy, infertility or infant pneumonia, the estimated costs for diagnosis and treatment in the USA amounts to 22 million US dollars for each 500 cases Therefore, there is a high need for correct, quick and cost-effective diagnosis and treatment of this urogenital tract infection New innovative therapies provide good results with regard to efficacy and patients’ compliance The success rates of treatments are at least 95% However, the occurrence of antibiotic resistance should not be ignored and new treatment schemes must be developed The state-of-the-art of diagnosis and treatment of chlamydial infections as well as the pathophysiology is discussed in this review In conclusion, infections with C trachomatis is an important public health problem, especially in third world and developing countries, and more socio-economic studies linking secondary prevention of chlamydial infections, infertility and adverse pregnancy outcome are needed to understand more of its aetiology In addition, diagnosis and treatment should be improved Data in men revealed that past infections but not present infections are more related to male infertility There is still controversial results In future studies, function of the seminal vesicles and evaluation of the antioxidant capacity should be taken into account when role of C trachomatis infection on male fertility is assessed

A Review of Core Compact Models for Undoped Double-Gate SOI MOSFETs

Abstract: In this paper, we review the compact-modeling framework for undoped double-gate (DG) silicon-on-insulator (SOI) MOSFETs. The use of multiple gates has emerged as a new technology to possibly replace the conventional planar MOSFET when its feature size is scaled to the sub-50-nm regime. MOSFET technology has been the choice for mainstream digital circuits for very large scale integration as well as for other high-frequency applications in the low-gigahertz range. But the continuing scaling of MOSFET presents many challenges, and multiple-gate, particularly DG, SOI devices seem to be attractive alternatives as they can effectively reduce the short-channel effects and yield higher current drive. Core compact models, including the analysis for surface potential and drain-current, for both the symmetric and asymmetric DG SOI MOSFETs, are discussed and compared. Numerical simulations are also included in order to assess the validity of the models reviewed

Classical tests of general relativity: Brane-world Sun from minimal geometric deformation

Abstract: We consider a solution of the effective four-dimensional brane-world equations, obtained from the general relativistic Schwarzschild metric via the principle of minimal geometric deformation, and investigate the corresponding signatures stemming from the possible existence of a warped extra-dimension. In particular, we derive bounds on an extra-dimensional parameter, closely related with the fundamental gravitational length, from the experimental results of the classical tests of general relativity in the Solar system.

Nutritional improvement of beans (Phaseolus vulgaris) by natural fermentation

Abstract: The effect of natural fermentation of flour and whole bean seeds (Phaseolus vulgaris) on the content of nutrients (protein, fat, starch, dietary fiber, vitamins B1 and B2) and antinutritional factors (α-galactosides, trypsin inhibitor activity and inositol phosphates) has been studied. After fermentation, total protein content decreased (2–15%) but the in vitro protein digestibility increased (4–8%) and the fat content did not change. In fermented bean flours, fructose and sucrose decreased (67–83% and 99–100% respectively), glucose increased (175–750%) and galactose was present at the concentration 1:4 g/ml (flour:water), but when whole beans were fermented none of these soluble sugars were detected. Total starch, available starch, insoluble fiber content decreased after fermentation (5–13%, 10–24%, and 5–26%, respectively), which was less pronounced in whole fermented beans. The soluble dietary fiber decreased (61–71%). The vitamin B1 content decreased (17–38%) and the vitamin B2 content increased (16–35%) after fermentation. Fe, P, Mg, Ca, and K decreased and Zn content did not change after natural fermentation. In either fermented flour or whole beans, the alpha-galactosides and IP6 decreased (99–100%, 7–39% respectively); however in fermented flour beans IP5 content did not modify or decrease and IP4 content could also increase. When whole bean grains were fermented no IP5 and IP4 was detected. TIA levels and tannins content decreased (58–71% and 61–70%) after fermentation. Natural fermentation of beans has been a very effective process for increasing functionality of Phaseolus vulgaris and the whole bean fermentation is very promising due to the lower cost.