305 research outputs found

    Infinite point and Riemann–Stieltjes integral conditions for an integro-differential equation

    Get PDF
    In this paper, we study the existence of solutions for two nonlocal problems of integro-differential equation with nonlocal infinite-point and Riemann–Stieltjes integral boundary conditions. The continuous dependence of the solution will be studied. &nbsp

    Voltammetric determination of melatonin in tablet dosage forms and human serum

    Get PDF
    The electrochemical oxidation of melatonin is studied in Britton-Robinson buffer in the pH range 2.2-11.8 by cyclic voltammetry at glassy carbon electrode. Three irreversible, diffusion-controlled oxidation peaks were obtained. The utility of using differential pulse and square wave techniques for determination of melatonin was examined. Different parameters affecting the peak current were analylzed and at optimum conditions, linear calibration plots from 0.02-0.5 mM and 0.04 to 0.5 mM of melatonin were obtained applying the two techniques, respectively. The differential pulse mode was successfully applied to the determination of melatonin in commercial tablets containing about three-folds of vitamin B6 without previous separation. The same technique was also used for melatonin determination in human serum with acceptable accuracy.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Voltammetric determination of melatonin in tablet dosage forms and human serum

    Get PDF
    The electrochemical oxidation of melatonin is studied in Britton-Robinson buffer in the pH range 2.2-11.8 by cyclic voltammetry at glassy carbon electrode. Three irreversible, diffusion-controlled oxidation peaks were obtained. The utility of using differential pulse and square wave techniques for determination of melatonin was examined. Different parameters affecting the peak current were analylzed and at optimum conditions, linear calibration plots from 0.02-0.5 mM and 0.04 to 0.5 mM of melatonin were obtained applying the two techniques, respectively. The differential pulse mode was successfully applied to the determination of melatonin in commercial tablets containing about three-folds of vitamin B6 without previous separation. The same technique was also used for melatonin determination in human serum with acceptable accuracy.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Renal expression of vascular endothelial growth factor in lupus nephritis in the pediatric age group

    Get PDF
    Background: Vascular endothelial growth factor (VEGF) plays a crucial role in preservation of renal functions and may also serve as a useful biomarker in monitoring the progression of lupus nephritis (LN). Objective: We thought to correlate VEGF expression in the kidney with renal histopathology in lupus nephritis to unveil its possible relation to disease activity and severity.Methods: We consecutively enrolled 15 patients with lupus nephritis and ten renal biopsy specimens from patients with cystic renal diseases as controls. The study measurements included SLEDAI, SLICC/ ACR damage index and BILAG renal score. Paraffin sections from renal biopsies were subjected to routine haematoxylin and eosin staining and Immunohistochemical staining for VEGF. Results: Among SLE patients, 7 (46.7%) showed mild expression of VEGF, 5 (33.3%) showed moderate while 3 (20%) had strong expression of the marker. On the contrary, the control samples (100%) revealed strong marker expression. All subjects with class IV and V lupus nephritis had mild renal expression of VEGF. Renal expression of VEGF had a significant positive correlation with serum creatinine and complement C3 levels. The 24 hours’ excretion of urinary proteins had a significant negative correlation with the renal expression of the marker. On the other hand, the activity indices and therapeutic modalities did not correlate with VEGF expression. Conclusion: This pilot study among pediatric cases of SLE revealed mild to moderate VEGF expression in most cases of proliferative LN. Further longitudinal studies are needed to investigate the consequences of this finding on the prognosis of the disease.Keywords: VEGF, SLE, renal biopsy, lupus nephritis

    Screening, morphological and molecular characterization of fungi producing cystathionine γ-lyase

    Get PDF
    The potency for production of cystathionine γ-lyase (CGL) by the fungal isolates was screened. Among the tested twenty-two isolates, Aspergillus carneus was the potent CGL producer (6.29 U/mg), followed by A. ochraceous (6.03 U/mg), A. versicolor (2.51 U/mg), A. candidus (2.12 U/mg), A. niveus and Penicillium notatum (2.0 U/mg). The potent six isolates producing CGL was characterized morphologically, A. carneus KF723837 was further molecularly characterized based on the sequence of 18S–28S rDNA. Upon sulfur starvation, the yield of A. carneus extracellular CGL was increased by about 1.7- and 4.1-fold comparing to non-sulfur starved and L-methionine free medium, respectively. Also, the uptake of L-methionine was duplicated upon sulfur starvation, assuming the activation of specific transporters for L-methionine and efflux of CGL. Also, the intracellular thiols and GDH activity of A. carneus was strongly increased by S starvation, revealing the activation of in vivo metabolic antioxidant systems. Upon irradiation of A. carneus by 2.0 kGy of γ-rays, the activity of CGL was increased by two-fold, regarding to control, with an obvious decreases on its yield upon further doses. Practically, CGL activity from the solid A. carneus cultures, using rice bran as substrate, was increased by 1.2-fold, comparing to submerged cultures, under optimum conditions

    Adaptive Scatter Search to Solve the Minimum Connected Dominating Set Problem for Efficient Management of Wireless Networks

    Get PDF
    An efficient routing using a virtual backbone (VB) network is one of the most significant improvements in the wireless sensor network (WSN). One promising method for selecting this subset of network nodes is by finding the minimum connected dominating set (MCDS), where the searching space for finding a route is restricted to nodes in this MCDS. Thus, finding MCDS in a WSN provides a flexible low-cost solution for the problem of event monitoring, particularly in places with limited or dangerous access to humans as is the case for most WSN deployments. In this paper, we proposed an adaptive scatter search (ASS-MCDS) algorithm that finds the near-optimal solution to this problem. The proposed method invokes a composite fitness function that aims to maximize the solution coverness and connectivity and minimize its cardinality. Moreover, the ASS-MCDS methods modified the scatter search framework through new local search and solution update procedures that maintain the search objectives. We tested the performance of our proposed algorithm using different benchmark-test-graph sets available in the literature. Experiments results show that our proposed algorithm gave good results in terms of solution quality
    corecore