125 research outputs found

    Design, structural and theoretical characterizations of novel Schiff base compounds: Enzymes inhibitory potential using in vitro and in silico methods

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    The aim of this paper is to further explore the enzymatic properties of two synthetic Schiff base compounds. The corresponding copper complex (Cu(L)), with its Schiff base ligand (HL) have been synthesized and their spectroscopic (IR, UV-visible., NMR (H,C, Dept-135) and MS), thermogravimetric (TG/DTG), electrochemical (CV) and theoretical (Density Functional Theory) using the hybrid B3LYP/6–31 G(d,p) method) properties have been studied and well discussed. The electrochemical behaviour of Cu(L) displays the Cu(III)/Cu(II) and Cu(lI)/Cu(I) redox processes. The molecular structure of HL is confirmed by X-ray diffraction analysis. HL crystalized in the triclinic system with the space group of P-1. The morphological structures are also analyzed by X-ray powder diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy. To improve their biological activities, inhibition of the target proteins, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), Tyrosinase (TYR), and Urease enzymes are tested in vitro and in silico using molecular docking. Furthermore, their ADMET parameters are analyzed. The drug-likeness results indicate that HL followed to Lipinski’s, Ghose’s, Veber’s, Egan’s and Muegge’s rules contrary to its copper complex which followed only to Veber’s rule. Due to the importance of cytochrome P450s proteins for detoxification, five major CYP isoforms (CYP1A2, CYP2C19, CYP2C9, CYP2D6, and CYP3A4) are also considered during in silico prediction.The authors thank the Algerian Ministry of Higher Education and Scientific Research (MESRS) and the Director General for Scientific Research and Technological Development (DGRSDT) for the financial support

    Endothelial dysfunction in obese non-hypertensive children without evidence of sleep disordered breathing

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    <p>Abstract</p> <p>Background</p> <p>Endothelial dysfunction is a complication of both obesity and obstructive sleep apnea syndrome (OSAS), the latter being highly prevalent among obese children. It is unknown whether obesity causes endothelial dysfunction in children in the absence of OSAS. This study examines endothelial function in obese and non-obese children without OSAS.</p> <p>Methods</p> <p>Pre-pubertal non-hypertensive children were recruited. Endothelial function was assessed in a morning fasted state, using a modified hyperemic test involving cuff-induced occlusion of the radial and ulnar arteries. The absence of OSAS was confirmed by overnight polysomnography. Anthropometry was also performed.</p> <p>Results</p> <p>55 obese children (mean age 8.6 ± 1.4 years, mean BMI z-score: 2.3 ± 0.3) were compared to 50 non-obese children (mean age 8.0 ± 1.6 years, mean BMI z-score 0.3 ± 0.9). Significant delays to peak capillary reperfusion after occlusion release occurred in obese compared to non-obese children (45.3 ± 21.9 sec <it>vs</it>. 31.5 ± 14.1 sec, p < 0.01), but no differences in the magnitude of hyperemia emerged. Time to peak reperfusion and percentage of body fat were positively correlated (r = 0.365, p < 0.01).</p> <p>Conclusions</p> <p>Our findings confirm that endothelial dysfunction occurs early in life in obese children, even in the absence of OSAS. Thus, mechanisms underlying endothelial dysfunction in pediatric obesity are operational in the absence of sleep-disordered breathing.</p

    Noninvasive assessment of arterial function in children: clinical applications

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    Non invasive methods to assess arterial function are widely used in adults. The development and progression of arterial vascular disease is a multifactorial process that can start early in life, thus even in a pediatric population. Risk factors for cardiovascular disease mediate their effects by altering the structure, properties and function of wall and endothelial components of the arterial blood vessels. The ability to detect and monitor sub-clinical damage, representing the cumulative and integrated influence of risk factors in impairing arterial wall integrity, holds potential to further refine cardiovascular risk stratification and enable early intervention to prevent or attenuate disease progression. Measurements that provide more direct information in relation to changes in arterial wall integrity clearly hold predictive and therapeutic potential. The aim of this current review will be to describe the non-invasive procedure used in children to investigate the mechanical properties of a great elastic artery, the common carotid, and the endothelial function of the brachial artery. The accuracy of recording noninvasively the blood pressure wave contour along the arterial tree has been improved by the technique of applanation tonometry. The results obtained with these methods in previous studies are described

    A Closed-Loop Reciprocity Calibration Method for Massive MIMO in Terrestrial Broadcasting Systems

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    Massive multi-input multi-output (MIMO) is believed to be an effective technique for future terrestrial broadcasting systems. Reciprocity calibration is one of the major practical challenges for massive MIMO systems operating in Time-Division Duplexing (TDD) mode. A new closed-loop reciprocity calibration method is investigated in this paper which can support online calibration with a higher accuracy compared to the existing methods. In the first part of the proposed method, an optimized relative calibration is introduced using the same structure of traditional relative calibration but with less impaired hardware in the reference radio chain. In the second part, a test device (TD) based calibration is proposed which makes online calibration possible. An experiment setup is built for the measurement of the BS hardware impairments and TD based calibration implementation. Simulation results and the error vector magnitude (EVM) of UE received signal after calibration show that the performance of our proposed method is improved significantly compared to the existing relative calibration methods
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