Determination of cefotaxime, cefoperazone, ceftazidime and cefadroxil using surface plasmon resonance band of silver nanoparticles

The aim of this work is to evaluate simple, sensitive, effective and validated procedures for the determination of cefotaxime, cefoperazone, ceftazidime and cefadroxil. In this study, the methods based on the ability of the cited drugs to reduce Ag+ ions to silver nanoparticles (Ag-NPs) in the presence of Polyvinyl Pyrrolidone (PVP) as a stabilizing agent producing very intense surface plasmon resonance peak of Ag-NPs (λmax. = 410-430 nm). The plasmon absorbance of the Ag-NPs allows the quantitative spectrophotometric determination of the cited drugs. The calibration curves are linear with concentration ranges of 0.4-3.2, 1-8, 0.5-4.0 and 1.5-9.0 µg/mL for cefotaxime, cefoperazone, ceftazidime and cefadroxil, respectively. Apparent molar absorptivity, detection and quantitative limits are calculated. Applications of the proposed methods to representative pharmaceutical formulations are successfully presented. The extracellular synthesis of nanoparticles is fast, and the method doesn’ t require various elaborate treatments and tedious extraction procedures

Electrocatalysis In Li-S Batteries

Stabilizing polysulfide-shuttle process while ensuring high sulfur loading holds the key to realize high theoretical energy density (2500 Wh/kg) of lithium-sulfur (Li-S) batteries. Though several carbon based porous materials have been used as host structures for sulfur and its intermediate polysulfides, the week adsorption of polysulfides on carbon surface and its poor reaction kinetics limits them from practical application. Here, we preset a novel ‘electcatalysis’ approach to stabilize polysulfide shuttle process and also enhance its red-ox kinetics. As a proof of concept, we have studied in-detail using conventional electrocatalyst i.e Pt/graphene composite, further the same extended to cost-effective electrocatalysts such as WS2 nanosheets and Metal carbides for viable practical applications. Nature of electrocatalyst, concentration of polysulfides, temperature of the cell etc., on electrochemical properties will be discussed. We reveal substantial improvement in electrochemical properties such as specific capacity, rate capability, coulombic efficiency etc. and corroborate our findings with systematic experimental studies. Interaction between electrocatalyst and polysulfides has been evaluated by conducting X-ray photoelectron spectroscopy and electron microscopy studies at various electrochemical conditions. Thus, introducing a catalyst in the Li−S system will open a new avenue for improving electrochemical performance

Modeling Cellular Networks in Fading Environments with Dominant Specular Components

Stochastic geometry (SG) has been widely accepted as a fundamental tool for modeling and analyzing cellular networks. However, the fading models used with SG analysis are mainly confined to the simplistic Rayleigh fading, which is extended to the Nakagami-m fading in some special cases. However, neither the Rayleigh nor the Nakagami-m accounts for dominant specular components (DSCs) which may appear in realistic fading channels. In this paper, we present a tractable model for cellular networks with generalized two-ray (GTR) fading channel. The GTR fading explicitly accounts for two DSCs in addition to the diffuse components and offers high flexibility to capture diverse fading channels that appear in realistic outdoor/indoor wireless communication scenarios. It also encompasses the famous Rayleigh and Rician fading as special cases. To this end, the prominent effect of DSCs is highlighted in terms of average spectral efficiency.Comment: IEEE ICC1

Modeling and Analysis of Cellular Networks Using Stochastic Geometry: A Tutorial

This paper presents a tutorial on stochastic geometry (SG)-based analysis for cellular networks. This tutorial is distinguished by its depth with respect to wireless communication details and its focus on cellular networks. This paper starts by modeling and analyzing the baseband interference in a baseline single-tier downlink cellular network with single antenna base stations and universal frequency reuse. Then, it characterizes signal-to-interference-plus-noise-ratio and its related performance metrics. In particular, a unified approach to conduct error probability, outage probability, and transmission rate analysis is presented. Although the main focus of this paper is on cellular networks, the presented unified approach applies for other types of wireless networks that impose interference protection around receivers. This paper then extends the unified approach to capture cellular network characteristics (e.g., frequency reuse, multiple antenna, power control, etc.). It also presents numerical examples associated with demonstrations and discussions. To this end, this paper highlights the state-of-the-art research and points out future research directions

Synthesis, Characterization, and In Vivo Anti-Cancer Activity of New Metal Complexes Derived from Isatin-N(4)antipyrinethiosemicarbazone Ligand Against Ehrlich Ascites Carcinoma Cells

The current study aimed to synthesize new metal coordination complexes with potential biomedical applications. Metal complexes were prepared via the reaction of isatin-N(4)anti- pyrinethiosemicarbazone ligand 1 with Cu(II), Ni(II), Co(II), Zn(II), and Fe(III) ions. The obtained metal complexes 2–12 were characterized using elemental, spectral (1H-NMR, EPR, Mass, IR, UV-Vis) and thermal (TGA) techniques, as well as magnetic moment and molar conductance measurements. In addition, their geometries were studied using EPR and UV–Vis spectroscopy. To evaluate the in vivo anti-cancer activities of these complexes, the ligand 1 and its metal complexes 2, 7 and 9 were tested against solid tumors. The solid tumors were induced by subcutaneous (SC) injection of Ehrlich ascites carcinoma (EAC) cells in mice. The impact of the selected complexes on the reduction of tumor volume was determined. Also, the expression levels of vascular endothelial growth factor (VEGF) and cysteine aspartyl-specific protease-7 (caspase-7) in tumor and liver tissues of mice bearing EAC tumor were determined. Moreover, their effects on alanine transaminase (ALT), aspartate transaminase (AST), albumin, and glucose levels were measured. The results revealed that the tested compounds, especially complex 9, reduced tumor volume, inhibited the expression of VEGF, and induced the expression of caspase-7. Additionally, they restored the levels of ALT, AST, albumin, and glucose close to their normal levels. Taken together, our newly synthesized metal complexes are promising anti-cancer agents against solid tumors induced by EAC cells as supported by the inhibition of VEGF and induction of caspase-7

Screening for psychological distress among High School Graduates Accepted for Enrollment at Alexandria Faculty of Medicine: Academic year 2016/2017

Background: Mental and psychological health of adolescents in general and prospective medical students in particular is a priority area to investigate as it affects wellbeing of the future doctors.Objectives: The current research was conducted to screen first year medical students accepted for enrollment at Alexandria Faculty of Medicine to identify those with a high probability of having psychological distress before the start of academic courses as well as explore the sources of stress among them.Methods: A cross sectional survey of 779 high school graduates accepted for admission to Alexandria Faculty of medicine was conducted. Participants were approached on the days of obligatory pre-enrollment medical examination. The translated Arabic version of DASS 21 questionnaire was used to screen students for three negative emotional symptoms namely depression, anxiety and stress. Inquiry about age, sex, residency and type of high school was added.Results: More than a tenth of studied medical students (12.6%) suffered from severe or profound stress and 29.1% of them had mild to moderate stress. Moreover, one fifth (20%) of studied students were severely anxious and less than one third (29.3%) had mild to moderate anxiety. Severe and profound depression was diagnosed among 14.3% of students whereas, 18.7% them were moderately depressed. No association was found between any of studied negative emotional symptoms and the students’ educational background or their residency.Conclusion: Nearly half of the prospective medical students might have some sort of psychological distress before starting their study in the Faculty of Medicine. They should be investigated to verify diagnosis and start intervention to minimize its adverse effects on academic performance and advancement at the faculty. Stress management courses should be considered for all medical students.Keywords: Psychological distress, Prospective medical students, Adolescents’ psychological health, Depression, Anxiety, Stres

New metal complexes derived from diacetylmonoxime-n(4)antipyrinylthiosemicarbazone: Synthesis, characterization and evaluation of antitumor activity against Ehrlich solid tumors induced in mice

The present study aimed to synthesize new metal complexes of diacetylmonoxime-N(4)antipyrinylthiosemicarbazone ligand and evaluate their antitumor activity. New complexes with ferric, cobalt, nickel and copper ions were prepared. Elemental, 1H Nuclear magnetic resonance, Mass spectroscopy, Electron paramagnetic resonance, Fourier Transform InfraredSpectroscopy, Ultraviolet–visible and thermal gravimetricanalysis were used to characterize the obtained complexes 1–11. An in vivo tumor model was established to investigate the effect of the naked ligand and its metal complexes 2, 5 and 8. Ehrlich ascites carcinoma solid tumor was induced in mice through subcutaneous inoculation of Ehrlich ascites carcinoma cells. The volumes of the formed solid tumors, the alanine transaminase, aspartate transaminase, albumin concentration in the serum, as well as the levels of Ki67 and p53 proteins in tumor and liver tissues were detected. All the tested complexes, especially complex 5, possessed proliferative inhibition manifested as the reduction of the tumor volume, Alanine aminotransferase & Aspartate aminotransferase activity, and the level of the Ki67 protein. Additionally, they restored the albumin concentration to normal levels as well increased the level of pro-apoptotic p53 protein. In conclusion, the antitumor activity of the newly synthesized metal complexes against Ehrlich ascites carcinoma solid tumors was proved to be mediated by the inhibition of Ki67 and induction of p53 proteins