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611.
Ghada M. Sami 《Czechoslovak Journal of Physics》2005,55(5):555-562
The complete time-domain fields due to a vertical magnetic dipole on the surface of two-layer earth model are reexamined when the usually neglected magnetic permeability contrast is considered using the natural-frequency concept. It is shown that for two-layered earth model, where the upper one is permeable, the electromagnetic induction response is modified with respect to the nonpermeable case. The step responses of the induced voltage in a horizontal receiving loop is found to have definite diagnostic features for the ground beneath. These features have been demonstrated by numerical results and illustrated by figures. 相似文献
612.
Krit Suknuntha Vimon Tantishaiyakul Visit Vao‐Soongnern Youssef Espidel Terrence Cosgrove 《Journal of Polymer Science.Polymer Physics》2008,46(12):1258-1264
Blends of chitosan and poly(vinyl pyrrolidone) (PVP) have a high potential for use in various biomedical applications and in advanced drug‐delivery systems. Recently, the physical and chemical properties of these blends have been extensively characterized. However, the molecular interaction between these two polymers is not fully understood. In this study, the intermolecular interaction between chitosan and PVP was experimentally investigated using 13C cross‐polarization magic angle‐spinning nuclear magnetic resonance (13C CP/MAS NMR) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). According to these experimental results, the interaction between the polymers takes place through the carbonyl group of PVP and either the OH? C6, OH? C3, or NH? C2 of chitosan. In an attempt to identify the interacting groups of these polymers, molecular modeling simulation was performed. Molecular simulation was able to clarify that the hydrogen atom of OH? C6 of chitosan was the most favorable site to form hydrogen bonding with the oxygen atom of C?O of PVP, followed by that of OH? C3, whereas that of NH? C2 was the weakest proton donor group. The nitrogen atom of PVP was not involved in the intermolecular interaction between these polymers. Furthermore, the interactions between these polymers are higher when PVP concentrations are lower, and interactions decrease with increasing amounts of PVP. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1258–1264, 2008 相似文献
613.
A simple and reliable liquid chromatographic method has been developed and validated for the determination of cefdinir in human urine and capsule samples. A chromatographic separation was achieved on a C18 column using a mobile phase consisting of potassium dihydrogen phosphate (10 mM, pH 4.5)–acetonitrile (90:10, v/v). Quantitation was achieved with UV detection at 285 nm, based on peak area with linear calibration curve at a concentration range of 0.7–39 µg mL−1. This method was successfully applied for the establishment of an urinary excretion pattern after oral dose.
相似文献614.
Renormalized Solutions of Nonlinear Parabolic Equations in Weigthed Variable-Exponent Space 下载免费PDF全文
This article is devoted to study the existence of renormalized solutions for the nonlinear p(x)-parabolic problemin the Weighted-Variable-Exponent Sobolev spaces, without the sign condition and the coercivity condition. 相似文献
615.
Existence of Renormalized Solutions of Nonlinear Elliptic Problems in Weighted Variable-Exponent Space 下载免费PDF全文
Youssef Akdim & Chakir Allalou 《数学研究》2015,48(4):375-397
In this article, we study a general class of nonlinear degenerated elliptic
problems associated with the differential inclusion $β(u)-div(a(x,Du)+F(u)) ∋ f$ in $Ω$ where $f ∈ L^1(Ω).$ A vector field $a(.,.)$ is a Carathéodory function. Using truncation
techniques and the generalized monotonicity method in the framework of weighted
variable exponent Sobolev spaces, we prove existence of renormalized solutions for
general $L^1$-data. 相似文献
616.
Abdelhalim Hafid Ahmed Taoufik Abella Bouaaddi Hassan Elouaddi Ahmed Tirbiyine Brahim Lmouden Mustapha Bghour Habiba El hamidi Youssef Ait Ahmed 《Chinese Journal of Physics (Taipei)》2018,56(2):754-759
In this paper, the critical current Jc(Θ) have been investigated as a function of magnetic-field angle Θ. Θ is the angle between the c-axis and the applied magnetic field direction. This investigation concerned three temperature values (60?K, 78?K and 81?K). The normalized pinning force fp versus the normalized magnetic field h was also studied (fp?=?Fp / Fpmax and h?=?H / Hmax). The Fp expression was determined based on the Kramer model.The studied sample was a single crystal of YBaCuO thin film deposited by the ablation laser method on the surface (100) of a SrTiO3 substrate.The results of this work show the existence of point core pinning of the normal centers in the low field regime and the occurrence of the flux creep in high field regime. 相似文献
617.
Green-Naghdi (G-N) theory of thermoelasticity is employed to study the deformation of micropolar thermoelastic solid with voids considering the influence of varions sources acting on the plane surface.... 相似文献
618.
Jilan A. Nazeam Ghada M. Ragab Amira A. El-Gazar Shereen S. El-Mancy Lina Jamil Sahar M. Fayez 《Molecules (Basel, Switzerland)》2021,26(18)
Antimicrobial resistance is a dramatic global threat; however, the slow progress of new antibiotic development has impeded the identification of viable alternative strategies. Natural antioxidant-based antibacterial approaches may provide potent therapeutic abilities to effectively block resistance microbes’ pathways. While essential oils (EOs) have been reported as antimicrobial agents, its application is still limited ascribed to its low solubility and stability characters; additionally, the related biomolecular mechanisms are not fully understood. Hence, the study aimed to develop a nano-gel natural preparation with multiple molecular mechanisms that could combat bacterial resistance in an acne vulgaris model. A nano-emulgel of thyme/clove EOs (NEG8) was designed, standardized, and its antimicrobial activity was screened in vitro and in vivo against genetically identified skin bacterial clinical isolates (Pseudomonas stutzeri, Enterococcus faecium and Bacillus thuringiensis). As per our findings, NEG8 exhibited bacteriostatic and potent biofilm inhibition activities. An in vivo model was also established using the commercially available therapeutic, adapalene in contra genetically identified microorganism. Improvement in rat behavior was reported for the first time and NEG8 abated the dermal contents/protein expression of IGF-1, TGF-β/collagen, Wnt/β-catenin, JAK2/STAT-3, NE, 5-HT, and the inflammatory markers; p(Ser536) NF-κBp65, TLR-2, and IL-6. Moreover, the level of dopamine, protective anti-inflammatory cytokine, IL-10 and PPAR-γ protein were enhanced, also the skin histological structures were improved. Thus, NEG8 could be a future potential topical clinical alternate to synthetic agents, with dual merit mechanism as bacteriostatic antibiotic action and non-antibiotic microbial pathway inhibitor. 相似文献
619.
Ehab Abdel‐Latif Altaf S. Almatari Ghada E. Abd‐ElGhani 《Journal of heterocyclic chemistry》2019,56(7):1978-1985
2‐Cyanoacetamido‐thiazole ( 1 ) was employed as a key for the construction of 6‐cyano‐7‐oxo‐7H‐thiazolo[3,2‐a]pyrimidine ( 4 ) which underwent reaction with hydrazine, malononitrile, ethyl cyanoacetate, and/or various 1,3‐bi‐nuclophilic reagents furnished the corresponding tri‐heterocyclic and tetra‐heterocyclic ring systems 5 – 12 . In addition, the reactions of 1 with various types of arylidene‐malononitriles and/or ethyl 3‐aryl‐2‐cyanoacrylates yielded the corresponding 1‐thiazolyl‐pyridine derivatives 16 and 20 , respectively. Furthermore, treatment of the precursor 1 with carbon disulfide and methyl iodide afforded the ketene dithioacetal derivative 21 which cyclized upon heating with hydrazine and/or 2‐aminobenzimidazole into the corresponding derivatives of N‐(thiazol‐2‐yl)‐1H‐pyrazole‐4‐carboxamide 22 and N‐(thiazol‐2‐yl)benzimidazo[1,2‐a]‐pyrimidine‐3‐carboxamide 23 . The antibacterial properties of these thiazole‐based heterocycles were examined against panel of two bacterial strains. 相似文献
620.
Mohamed Ali Ben Aissa Sabri Hassen Youssef Arfaoui 《International journal of quantum chemistry》2019,119(6):e25837
Chalcogen bonding is a noncovalent interaction, highly similar to halogen and hydrogen bonding, occurring between a chalcogen atom and a nucleophilic region. Two density functional theory (DFT) approaches B3LY-D3 and B97-D3 were performed on a series of complexes formed between CX2 (X = S, Se, Te) and diazine (pyridazine, pyrimidine and pyrazine). Chalcogen atoms prefer interacting with the lone pair of a nitrogen atom rather than with the π-cloud of an aromatic ring. CTe2 and CSe2 form a stronger chalcogen bond than CS2. The electrostatic potential of CX2 (X = S, Se and Te) reveals the presence of two equivalent σ-holes, one on each chalcogen atom. These CX2 molecules interact with diazine giving rise to supramolecular interactions. Wiberg bond index and second-order perturbation theory analysis in NBO were performed to better understand the nature of the chalcogen bond interaction. 相似文献