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51.
介绍沉积岩(Sitione和Conglomerate)和火成岩(andesite和felsite)的γ射线的衰减系数与散射系数的测量方法和测量结果。四种材料均制成颗粒粗细不同的粉末,在制成样品。颗粒的尺寸有:0.17、0.13、0.095、0.035、0.063nm五种。同时也测量上述品种的天然岩石的衰减系数与散射系数。使用60Co、137Cs、133Ba等γ射线源,能量在0.36到1.33MeV范围。详细地研究了线性衰减系数μ,质量衰减系数μ/ρ、弛豫长度冲及侧边散射系数φ与颗粒直径d、样品密度ρ和γ射线能量是E的关系。发现线性衰减系数与d和E成反比与ρ成正比,而侧边散射系数与d和E成正比但与ρ成反比。比较此两大类岩石的μ和φ差异的原因。实验的结果认为这些材料可用于屏蔽γ射线。 相似文献
52.
53.
Omar Mahmoud Georgia Biazus Soares Gil Yosipovitch 《International journal of molecular sciences》2023,24(1)
Transient Receptor Potential (TRP) channels are multifunctional sensory molecules that are abundant in the skin and are involved in the sensory pathways of itch, pain, and inflammation. In this review article, we explore the complex physiology of different TRP channels, their role in modulating itch sensation, and their contributions to the pathophysiology of acute and chronic itch conditions. We also cover small molecule and topical TRP channel agents that are emerging as potential anti-pruritic treatments; some of which have shown great promise, with a few treatments advancing into clinical trials—namely, TRPV1, TRPV3, TRPA1, and TRPM8 targets. Lastly, we touch on possible ethnic differences in TRP channel genetic polymorphisms and how this may affect treatment response to TRP channel targets. Further controlled studies on the safety and efficacy of these emerging treatments is needed before clinical use. 相似文献
54.
Pter P. Lakatos Dvid rpd Kardi Anna Rita Galambos Nariman Essmat Kornl Kirly Rudolf Laufer Orsolya Geda Zoltn S. Zdori Tams Tbi Mahmoud Al-Khrasani va Szk 《International journal of molecular sciences》2022,23(17)
Current treatment approaches to manage neuropathic pain have a slow onset and their use is largely hampered by side-effects, thus there is a significant need for finding new medications. Tolperisone, a centrally acting muscle relaxant with a favorable side effect profile, has been reported to affect ion channels, which are targets for current first-line medications in neuropathic pain. Our aim was to explore its antinociceptive potency in rats developing neuropathic pain evoked by partial sciatic nerve ligation and the mechanisms involved. Acute oral tolperisone restores both the decreased paw pressure threshold and the elevated glutamate level in cerebrospinal fluid in neuropathic rats. These effects were comparable to those of pregabalin, a first-line medication in neuropathy. Tolperisone also inhibits release of glutamate from rat brain synaptosomes primarily by blockade of voltage-dependent sodium channels, although inhibition of calcium channels may also be involved at higher concentrations. However, pregabalin fails to affect glutamate release under our present conditions, indicating a different mechanism of action. These results lay the foundation of the avenue for repurposing tolperisone as an analgesic drug to relieve neuropathic pain. 相似文献
55.
El Sayed H. El Ashry Mahmoud A. M. Nassr Yeldez El Kilany Ahmed Mousaad 《Advanced Synthesis \u0026amp; Catalysis》1986,328(1):1-6
Oxidative cyclization of D -galactose (p-chlorophenyl)thiosemicarbazone gave 2-(p-chloroanilino)-5-( D -galacto-1,2,3,4,5-pentahydroxypentyl)-1,3,4-thiadiazole ( 1 ), whose acetylation afforded 2-[N-acetyl-N-(p-chlorophenyl)]-amino-5-( D -galacto-1,2,3,4,5-pentacetoxypentyl)- 1,3,4-thiadiazole ( 3 ). Its periodate oxidation of the glycol groups gave 2-(p-chloroanilino)-1,3,4-thiadiazole-5-carboxaldehyde ( 4 ), which can be transformed into 1,2-[2-(p-chloroanilino)-1,3,4-thiadiazol-5-yl]-1-hydroxy-2-oxoethane. A number of hydrazones of the formyl thiadiazole was prepared and its reduction with sodium borohydride gave 2-(p-chloroanilino)-5-hydroxymethyl-1,3,4-thiadiazole ( 6 ), whose acetylation gave a mono-O-acetyl derivative ( 7 ). Oxidation of the formyl thiadiazole gave 2-(p-chloroanilino)-1,3,4-thiadiazole ( 9 ). The spectral data of the compounds were discussed. 相似文献
56.
Field-assisted ion exchange of protons in type III silica for Cs or Nu ions from a molten salt was investigated. Although electrolysis occurred, infrared measurements showed no change in hydroxyl content after ion exchange for extended periods. Scanning electron microprobe studies of cesium-exchanged specimens revealed a high-cesium-content layer =2,μm thick; this layer is believed to result from surface reaction with the molten salt. 相似文献
57.
Mahmoud A. Zarraa 《化学工程与技术》1998,21(3):301-305
The effect of drag–reducing polymers on the rate of liquid – solid mass transfer in a packed bed reactor under forced convection conditions was studied by measuring the rate of diffusion–controlled dissolution of copper spheres in acidified chromate solutions. The variables investigated were superficial liquid velocity, sphere diameter, bed height, and polymer concentration. The mass transfer coefficient was found to increase with increasing superficial liquid velocity. Increasing both sphere diameter and bed height were found to decrease the mass transfer coefficient. Polymer addition was found to decrease the rate of mass transfer by an amount ranging from 29.2 to 56.9% depending on superficial liquid velocity and polymer concentration. Mass transfer data were correlated in absence and in the presence of drag–reducing polymer, using the following equations, respectively: Jd = 3.71Re–0.54 and, Jd = 2.5 Re–0.61where Jd is mass transfer J-factor and Re is the Reynolds number. 相似文献
58.
Manar El-Sayed Abdul-Raouf Abdul-Raheim Mahmoud Abdul-Raheim Nermine El-Sayed Maysour Hamed Mohamed 《Journal of surfactants and detergents》2011,14(2):185-193
Trimeric-type nonionic surfactants based on tris(2-aminoethyl)amine were prepared. N-alkyl chloride (namely, octanoyl chloride,
n-decanoyl chloride, n-dodecanoyl chloride) was reacted with tris(2-aminoethyl)amine in the presence of toluene and triethylamine. The products
were partially reduced and then ethoxylated by poly(ethylene glycol) of molecular weights 400, 1,000, and 2,000 g mol−1. The structures were confirmed by infrared (IR) and 1HNMR spectroscopy. The molecular weights of the surfactants were measured by gel permeation chromatography (GPC). The properties
of the prepared compounds were investigated by the surface tension, interfacial tension, and cloud point. The emulsification
power of the prepared surfactants for oil-in-water emulsions was also studied and the emulsion stability was monitored by
an optical microscope and the bottle testing method. Some factors affecting the emulsion stability were investigated 相似文献
59.
A theoretical investigation has been conducted for the prediction of the critical height at the onset of gas entrainment during single discharge from a stratified, two‐phase region, through a branch installed on an inclined flat wall. The predicted critical height at the onset of gas entrainment was proven to be a function of Froude number (Fr) and density ratio of the interface fluids. Three different experimental data sets at wall inclination angles of zero, 45 and 90 degrees (i.e. side, inclined and bottom branches) were used for comparisons. A good concurrence was illustrated between the experimental and theoretical values. 相似文献
60.
Investigation of transport phenomena in a hybrid ion exchange-electrodialysis system for the removal of copper ions 总被引:2,自引:0,他引:2
A. Mahmoud L. Muhr S. Vasiluk A. Aleynikoff F. Lapicque 《Journal of Applied Electrochemistry》2003,33(10):875-884
Hybrid ion exchange electrodialysis processes allow the removal of metal ions from dilute waste liquids and the recovery of more concentrated solutions. The work reported here was aimed at investigating the two steps in the treatment process, namely, adsorption of metal ions onto the packed bed of resin and electromigration (i.e., the transport of these ions in the complex system under the applied electrical field). The case of copper sulfate was investigated. Dowex resins with a cross-linking degree of 2 and 8% were used. The flux of copper through the resin bed and the current efficiency for ion transfer to the cathode compartment were determined as a function of potential gradient and copper ionic fraction in the bed. Apparent diffusion coefficients of Cu2+ in the overall system were deduced from the experimental data. 相似文献