932 research outputs found

    Homotopy Continuation Method for Solving a Class of Slightly Perturbed Equations

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    In the present paper, an iterative method of second order convergence for solving a class of slightly perturbed equations is established using homotopy continuation technique. The accuracy of the method is very high and verified through two applications, in the first application we fix all the input parameters of our algorithm and allow the homotopy function to vary. For this application we considered as a typical example, Kepler equation of elliptical motion. In the second applications, the function is fixed while the other input parameters of the algorithm are varied, and we used for these applications seven highly transcendental slightly perturbed equations. The most important characteristic of the method is that it does not need any priori knowledge of the initial guess, a property which avoids the critical situations between divergent to very slow convergent solutions, that may exist in the application of other numerical methods which depending on initial guess. Moreover, the method allows freedom in choosing the function in order to secure any required accuracy

    Experimental Results of a Wind Energy Conversion System with STATCOM Using Fuzzy Logic Controller

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    This paper describes a complete implementation of the experimental voltage regulation of a wind energy conversion system using STATCOM. Firstly conventional control technique is used which is proportional plus integral controller. The control technique is performed using a PC computer through a suitable interfacing and opt-isolating facilities. Secondly fuzzy logic controller is facilitated in this scheme to improve the performance of the experimental setup. Several efforts are done to choose the suitable gains of the fuzzy controller to achieve superior performance of the wind system. Experimental results of the system show the effectiveness of the proposed technique in regulating the output voltage. Thanks to the operation of the STATCOM in controlling the reactive power of the system to fix the output voltage at the desired value regardless of the wind speed

    Changes in Physico-Chemical Quality and Volatile Compounds of Orange-Carrot Juice Blends During storage

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    The present study aimed to determine the changes in physico-chemical parameters (pH, total soluble solids “TSS”, total acidity, vitamin C, total carotene, total phenolic and antioxidant activity) as well as sensory evaluation and volatile constituents of the orange juice samples mixed with carrot juice at ratios (1:3, 3:1 and 1:1). While, the polyphenol content was determined using Folin–Ciocalteu, antioxidant activity was measured using two in vitro assays 2,2'-diphenyl-1-picrylhydrazyl (DPPH0) and metal chelating assays. While, the acidity increased, total carotene and pH of the juice decreased during the storage period. There were no significant changes in total phenolics throughout the storage period at the three blending ratios. A slight increase in antioxidant capacity during the storage period had been observed. The headspace volatiles of fresh orange and carrot juices as well as fresh and stored blend juice with ratio (1:3) for 14 days at refrigerator were collected and subjected to Gas chromatography (GC) and Gas chromatography-Mass spectrometery (GC-MS) analysis. A total of 26 volatile compounds were identified in samples of fresh orange and carrot juices as well as fresh and stored blend including 7 alcohols, 4 aldehydes, 9 monoterpene hydrocarbon and 6 esters. Limonene was the one most abundant monoterpene, representing in orange, carrot, fresh and stored blend 47.38, 42.37, 39.24 and 37.25%, respectively. Keywords: Orange- carrot juice, Blend, Antioxidant, Volatile compound

    Schottky Diode Graphene Based Sensors

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    Control of hyperphosphatemia in regular hemodialysis (HDx) patients by calcium acetate (CA) versus calcium carbonate (CC). A double blind crossover prospective study

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    This study included fourty chronic renal failure patients aged 37-83 years (mean 51.3±7) on thrice weekly HDx for 4-144 month (Kt/V >1.2). Acetate dialysate with calcium concentration of 3 mEq/L was used. All phosphate binders were discontinued for one month. Patients were divided in two groups. Group I (20 cases) received CA, while group II (20 cases) received CC in equimolar dose (10 mmol, of either t.i.d.) for one month. Crossover of treatment was done for another month while keeping patients on the same diet.Serum levels of total calcium (Ca), ionized Ca (iCa), phosphorus (P), alkaline phosphates (AP), urea (U), creatinine (Cr), ALT, AST, total proteins (TP) and albumin (Alb) were estimated before, and at the end of each month of CA and CC treatment. Serum Ca and iCa were significantly lower in group I after CA compared to values after CC (p<0.01). Similar results in Ca levels were observed in group II (P<0.05). In group II only serurn P was significantly lower after CA compared to its values after CC (P<0.05). There was no significant difference in AP, U, Cr, ALT, AST, TP and Alb before, and at the end of each month of CA and CC treatment (P>0.05 in all). We excluded 12.5% of cases due to CA intolerance while non of cases had similar intolerance to CC.Conclusion: 1) CA is not very superior to CC in control of hyperphosphataemia. 2) CA can be safely increased without the risk of hypercalcemia. 3) Active Vitamin D and high dialysate Ca can be used to suppress parathyroid activity more safely with CA than with CC. 4) Tolerability to CC is superior

    Pulmonary prophylactic impact of melatonin and/or quercetin: A novel therapy for inflammatory hypoxic stress in rats

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    The study aims to compare, through histological and biochemical studies, the effects of quercetin, melatonin and their combination in regulation of immuno-inflammatory mediators and heat shock protein expressions in sodium nitrite induced hypoxia in rat lungs. The results revealed that NaNO2 injection caused a significant decrease in Hb in rats, while serum levels of TNF-α, IL-6 and CRP, VEGF and HSP70 were elevated compared to the control group. Administration of melatonin, quercetin or their combination before NaNO2 injection markedly reduced these parameters. Histopathological examination of the lung tissue supported these biochemical findings. The study suggests that melatonin and/or quercetin are responsible for lung tissue protection in hypoxia by downregulation of immuno-inflammatory mediators and heat shock protein expressions. Pre-treatment of hypoxic animals with a combination of melatonin and quercetin was effective in modulating most of the studied parameters to near-normal levels

    Immunohistochemical Study of Androgen Receptor Expression in Estrogen Receptor-Negative Invasive Breast Carcinoma and its Relation with Clinicopathologic Factors

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    BACKGROUND: Estrogen receptor (ER)-negative breast carcinomas lack the expression of ER and they have no targeted hormone therapies. The androgen receptor (AR) is a newly emerge biomarker. Detecting AR in these tumors may provide a target for future therapies. AIM: The aim of the study is to examine the immunohistochemical expression profiles of AR protein in ER-negative invasive breast carcinomas and to assess the relation between AR expression and the clinicopathologic factors such as age, tumor size, tumor grade, tumor type, immunohistochemical type, lymph node status, and Ki67 expression. METHODS: Sixty paraffin blocks of ER-negative invasive breast carcinoma cases were stained immunohistochemically by AR. Positive expression was defined as ≥1% nuclear staining. RESULTS: AR positivity was detected in 55% of the studied cases. The positive cases were scored by H-score with a median=117, and a range of 3–285 and by Allred score with a median=7, and a range of 3-8. AR is expressed in 60.9% of triple-negative breast carcinoma cases. AR expression was higher in older age, and there were significant positive correlations between the degree of AR expression (AR%, AR intensity, and H-score) and age (p=0.050, 0.007, 0.033, respectively). There was non-significant negative correlation between Ki67% and the degree of AR expression (AR%, AR intensity, H-score, and Allred score). Regarding different histological types, tumor grade, tumor size, lymph node status, and immunohistochemical types, there was no significant difference between AR positive and AR negative cases. CONCLUSION: AR is frequently expressed in ER-negative invasive breast carcinoma; especially in older age, and in a large number of triple-negative subtypes. This may give chance to benefit from future AR target therapy. We recommend further research work on AR expression in the special histologic subtypes of ER-negative breast carcinoma and in the triple negative group

    Oxidative Leaching Kinetics of Vanadium from Egyptian Boiler Ash under Acidic Oxidizing Conditions

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    Processing of Egyptian boiler ash in sulphuric acid solution using hydrogen peroxide as oxidant has been investigated. The results showed that leaching temperature, hydrogen peroxide, sulphuric acid concentration, leaching time, liquid-to-solid ratio and agitation speed, have significant effect; optimum process operating parameters were established as follows: temperature: 9
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