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Search Results: 1 - 10 of 15986 matches for " D ocking "
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In Silico Molecular Modelling and Docking of Quercetin - γ - Cyclodextrin Inclusion Complex on SGLT of Vibrio parahaemolyticus
Sushama Vaishnav (HOTA),Kulkarni G.K,Perumal P
International Journal of Pharmaceutical and Phytopharmacological Research , 2013,
Abstract: Quercetin glucosides are transported across intestinal epithelium by active transport. Is not significantly transported by sodiumlinked glucose transporter 1 (SGLT1) and shows lesser intestinal absorption than its glucosides. Quercetin complexes withcyclodextrins have been described to increase its solubility. It has long been assumed that cyclodextrins improve its intestinalabsorption by releasing it near intestinal epithelium and making quercetin available for passive diffusion. In silico molecularmodeling and docking studies provide an accurate and cost effective method to understand these interactions. X-ray crystalstructure of sodium dependent glucose transporter isolated from Vibrio parahaemolyticus was used asa model for dockingstudies. The test ligands including quercetin-γ-cyclodextrin, quercetin-3,4'-glucoside, quercetin-3-glucoside, and quercetin weredocked in predicted active site of Vibrio parahaemolyticus sodium linked glucose transporter (vSGLT). Validation of potentialmean force method used for docking was performed by docking glucose, a natural ligand of vSGLT. It was found that quercetinglucosides and quercetin-γ-cyclodextrin docked analogously with predicted active site of vSGLT and their docking scores werecomparable. Quercetin docked at a different location with less docking score. Theresults point towards possible mimicking ofglucose moieties by γ-cyclodextrin in mechanism of active transport of quercetin and its glycosides by SGLT.
The Effect of Short Term Vitamin D Supplementation on the Inflammatory and Oxidative Mediators of Arterial Stiffness  [PDF]
David Martins, Yuan-Xiang Meng, Naureen Tareen, Jorge Artaza, Jae Eun Lee, Caroline Farodolu, Gary Gibbons, Keith Norris
Health (Health) , 2014, DOI: 10.4236/health.2014.612185
Abstract: Background: Vitamin D deficiency has been implicated as a potential risk factor for cardiovascular disease. The high rate of vitamin D deficiency (<30 ng/ml) exhibited by African Americans may account for some of the excess prevalence of cardiovascular morbidity and mortality in this vulnerable US population. Vitamin D supplementation may reduce the risk of cardiovascular disease by ameliorating the onset and progression of arterial stiffness, a strong predictor of cardiovascular mortality, usually assessed by pulse wave velocity and augmentation index. Very few prospective studies have evaluated the effect of vitamin D supplementation on the inflammatory and oxidative stress mediators of arterial stiffness. Method: In a double blind randomized placebo controlled study we evaluated the effect of a monthly dose of 100,000IU of vitamin D3 for three months on the level of serum 25(OH)D, intact parathyroid hormone (PTH), urinary isoprostane, adipocyte cytokine expression and arterial stiffness among 130 overweight and obese (BMI > 25) African Americans with elevated blood pressure (130 - 150/85 - 100 mmHg) and low serum vitamin D level (10 - 25 ng/ml). Results: There was a significant increase in the serum 25(OH)D levels to a mean level of 34.5 ng/ml (SD = 7.1) with the intervention (p < 0.001). The increase in 25(OH)D levels was associated with a significant decrease in the serum level of intact PTH (p = 0.02), mean urinary isoprostane (p = 0.02) and adipocyte cytokine expression. Although the increase in the 25(OH)D levels was not associated with any significant change in the Pulse Wave Velocity (PWV) in the overall study sample, it was associated with a significant decrease in the augmentation index among the participants with the highest tertile of urinary isoprostane (p = 0.007). Conclusion: We concluded that vitamin D supplementation increased serum 25(OH)D levels, decreased intact PTH level and the levels of select inflammatory and oxidative stress mediators of arterial stiffness. Longer term prospective studies are warranted to evaluate the effect of high dose vitamin D supplementation on arterial stiffness.
Cr+3 Distribution in Al1 and Al2 Sites of Alexandrite (BeAl2O4: Cr3+) Induced by Annealing, Investigated by Optical Spectroscopy  [PDF]
Neilo M. TRINDADE, Rosa M. F. SCALVI, Luis V. A. SCALVI
Energy and Power Engineering (EPE) , 2010, DOI: 10.4236/epe.2010.21004
Abstract: In order to investigate optical properties of alexandrite, the present work deals with the influence of thermal annealing on optical absorption and luminescence spectra of natural samples. The exposure time to heat treatment at 1000oC is taken into account. Possible migration of Cr3+ ions from Al1 (inversion site) to Al2 (reflection site) is detected. Sample composition is obtained through Scanning Electron Microscopy (SEM) measurements and points to a rearrangement of Cr+3 and Fe3+ ions in the alexandrite crystalline structure, un-der thermal annealing influence. This feature may be used to control the optical properties of natural alexan-drite, which can be associated to the observed laser emission effect.
Conversion of U-238 and Th-232 Using a Fusion Neutron Source  [PDF]
Xianjun Zheng, Baiquan Deng, Wei Ou, Fujun Gou
World Journal of Nuclear Science and Technology (WJNST) , 2014, DOI: 10.4236/wjnst.2014.44028
Abstract: This article proposes a general framework for the conversion of U-238 and Th-232 utilizing fusion-produced neutrons. This recognizes that emerging fusion technologies may not produce sufficient net energy output to justify stand-alone applications, yet may be commercially viable for breeder transmutation or hybrid fusion-fission reactor concepts proposed herein to dispose of nuclear wastes and long life high radioactive fission products remaining in shutdown nuclear power plants. Results show that this could be achievable within a decade, given an appropriate fusion source. However, if 20% beryllium of nuclei density is added to the convertor blanket, the efficiency of the conversion process can be significantly increased. Also, the neutron energy spectrum resulting from dense D-D plasma core fusion is much softer than D-T fusion neutron source, hence the probability of (n, p) (n, α) backward decay reaction paths will be smaller and the conversion efficiency will be elevated.
Severe Thyrotoxicosis Does Not Accelerate 1a-Hydroxylation of 25-Hydroxyvitamin D3 in Dogs. Experimental Study  [PDF]
Christos Georgiou Velentzas
International Journal of Clinical Medicine (IJCM) , 2013, DOI: 10.4236/ijcm.2013.412093
Abstract:

Two healthy dogs weighing 18 kg and 13 kg each received an intravenous injection of 7 μg/kg 25-hydroxyvitamin D3 (25OHD3). Subsequently, they were blood-sampled in order to determine the plasma levels of 25(OH)D3 over 4-hourly time intervals and for a time period of 24 hours. After a period of 18 days since the last blood sampling, the animals were brought to a hyperthyroid state and the intravenous injection of 7 μg/kg 25OHD3 was repeated. Blood sampling was performed every 4 hours and over a time period of 24 hours in order to determine the levels of 25OHD3. The graphic plotting of plasma levels of 25OHD3 in the euthyroid state did not differ from that in the hyperthyroid state. This finding in dog animal experimentation is indicative that the increased levels of thyroid hormones did not affect the activity of CYP27B1 and CYP24A1 enzymes that are related to the catabolism of 25OHD3 over a minimum of 24 hours period.

Necessity for Vitamin D Screening among Urban Bedouin Women of Childbearing Age  [PDF]
Inna Rudoy, Ilia Volkov
Health (Health) , 2015, DOI: 10.4236/health.2015.75066
Abstract: Vitamin D (Vit D) plays multiple roles in bodily functions. Vit D deficiency is a common, but often under-diagnosed condition with possible serious complications. According to some research, Vit D is important particularly among women and children. No data were found concerning the Vit D status among urban Bedouin women of childbearing age. The research study is retrospective and descriptive. We analyzed 202 medical histories of patients undergoing blood tests for Vit D level for various reasons. The main objectives of the research were: 1) determining the prevalence of the Vit D deficiency among the Bedouin women of childbearing age; 2) identifying the causes for the physicians’ reasons for suspecting Vit D deficiency: the complaints or symptoms which cause the doctor to test for Vit D level. As a result, in 80.7% of those tested for Vit D, levels were less than 10 ng/ml, and in 19.3%, levels of 10 to 20 ng/ml were found. In lieu of our findings and in order to prevent serious health problems, Vit D screening plan should be seriously considered and discussed in the Bedouin population with high risk of deficiency.
Effect of external electric field upon charge distribution, energy and dipole moment of selected monosaccharide molecules  [PDF]
Jozef Mazurkiewicz, Piotr Tomasik
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.45040
Abstract: External electric field of 0.001, 0.01 and 0.05 a.u. changes distribution of the electron density in α- and β-D-glucose, α- and β-D-galactose, α- and β-fructopyranoses and α- and β-fructofuranoses, α- and β-D-ribofuranoses and α and β-D-xylo- furanoses. Hyper-Chem 8.0 software was used together with the AM1 method for optimization of the conformation of the molecules of monosaccharides under study. Then polarizability, charge distribution, potential and dipole moment for molecules placed in the external electric field of 0.000, 0.001, 0.01 and 0.05 a.u. were calculated involving DFT 3-21G method. Application of the external field induced polarizability of electrons, atoms and dipoles, the latter resulting in eventual reorientation of the molecules along the applied field of the molecules and the electron density redistribution at particular atoms. Increase in the field strength generated mostly irregular changes of the electron densities at particular atoms of the molecules as well as polarizabilities. Energy of these molecules and their dipole moments also varied with the strength of the field applied. Results of computations imply that saccharides present in the living organisms may participate in the response of the living organisms to the external electric field affecting metabolism of the molecules in the body fluids by fitting molecules to the enzymes. Structural changes of saccharide components of the membranes can influence the membrane permeability.
Vitamin D Toxicity in Adults: A Case Series from an Area with Endemic Hypovitaminosis D
Parvaiz A. Koul,Sheikh Hilal Ahmad,Feroze Ahmad,Rafi A. Jan
Oman Medical Journal , 2011,
Abstract: Vitamin D deficiency state is endemic to the Kashmir valley of the Indian subcontinent. Physicians often treat patients with high doses of vitamin D for various ailments and on occasion the prescribed doses far exceed the requirements of the patients. Ten cases of hypercalcemia due to vitamin D intoxication are presented with features of vomiting, polyuria, polydipsia, encephalopathy and renal dysfunction. All the patients had demonstrable hypercalcemia and vitamin D levels were high in nine of the 10 cases. The patients had received high doses of vitamin D and no other cause of hypercalcemia was identified. Treatment of hypercalcemia resulted in clinical recovery in nine cases. We conclude that hypervitaminosis D must be considered in the differential diagnosis of patients with hypercalcemia in endemically vitamin D deficient areas. A careful history and appropriate biochemical investigation will unravel the diagnosis in most of the cases.
Relationship between body mass index and serum 25-hydroxyvitamin D stronger among Caucasians than African Americans in NHANES adults 2001-2006  [PDF]
Lenore Arab, John S. Adams, Heeyoung Kim, Alice Kohlmeier
Open Journal of Epidemiology (OJEpi) , 2012, DOI: 10.4236/ojepi.2012.21002
Abstract: The rapid decline in circulating levels of serum 25-hydroxyvitamin D in both African Americans and Caucasians in the US population remains unexplained, and appears to parallel the obesity epidemic. The cross sectional data on 7349 Caucasian and African American adults between 21 and 69 years of age from the continuous National Health and Nutrition Examination Study (NHANES) 2001 to 2006 were used to model by race, with smoothing functions, the true relationship between body mass index (BMI), waist circumference and serum 25-hydroxyvitamin D in men and women. Weighted regressions of determinants of serum 25-hydroxyvitamin D levels were analyzed. Serum 25-hydroxyvitamin D is negatively associated with BMI linearly above an inflection point at 20 kg/m2 and positively associated below a BMI of 20 kg/m2. The gender- and age-adjusted regression coefficients of BMI on 25-hydroxyvitamin D levels demonstrate a 50% lower coefficient (r = –0.18 ng/ml/ BMI unit) among African Americans than among Caucasians (r = –0.36 ng/ml/BMI unit). These relationships were as great in men as in women and were replicated when waist circumference was used as a surrogate for visceral fat levels. The extent to which BMI is a strong predictor of serum 25-hydroxyvitamin D levels depends upon BMI being greater than 20 kg/m2. The hockey stick shape of the BMI 25-hydroxyvitamin D relationship needs to be taken into account when adjusting serum values for BMI. Both this inflection and reduction in serum levels of 25-hydroxyvitamin D in the population may be due to sequestration in an increasing adipose tissue reservoir. The interpretation of serum 25-hydroxyvitamin D levels as a biomarker of vitamin D adequacy requires appropriate adjustment of body fat mass.
Mechanical Properties of Cement Mortar Containing Fine-Grained Fraction of Fly Ashes  [PDF]
Ewelina Tkaczewska
Open Journal of Civil Engineering (OJCE) , 2013, DOI: 10.4236/ojce.2013.32A007
Abstract:

This paper presents the effect of fly ash grain-size fractions on Portland-fly ash cement hydration and its properties. Siliceous fly ashes of size fraction of 0 - 16 and 16 - 32 μm, separated from initial fly ash samples from 1st, 2nd and 3rd hopper in ESP system, were analysed. Cement hydration was investigated by determination of hydration heat and content of Ca(OH)2 and C3S in cement samples. Water to cement ratio and initial setting time of cement pastes as well as compressive strength and microstructure of cement mortars were also analyzed. Results showed that the same amount of the same size ash fraction can give cement of lower or higher early strength and its lower or higher increase with time. Incorporation of 20 wt% of ash fraction of 0 - 16 μm can produce Portland-fly ash cement CEM II/A-V of strength class 42.5R (from 2nd hopper) or 52.5N (from 3rd hopper). Cement containing 40 wt% of ash fraction of 0 - 16 μm from 2nd and 3rd hopper can be classified as pozzolanic cements CEM IV/A-V of strength class 42.5 and normal or rapid early strength, respectively. Different development of strength of cement with addition of the same size ash fraction separated from the initial ash sample from the next hopper in ESP system is connected with higher depolymerization degree of SiO4 units in ash glass, resulting from the greater amount of AlO4 units replacing SiO4 units. Ash fraction of 16 - 32 μm shows lower depolymerisation of glass network and as a consequence lower hydration degree of C3S to portlandite and calcium silicate hydrates (C-S-H).

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