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1.
Waganat W. Wardakhan Yehya M. Elkholy 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2661-2673
Several new thiazole derivatives have been synthesized; the reactivity of these compounds toward amines, aldehydes, and hydroxyl amine are reported. New syntheses of pyrimidino[5,4:3,4]pyrazolo[4,3:5,6]pyridazine derivatives also have been achieved. 相似文献
2.
Y. M. Elkholy 《Chemistry of Heterocyclic Compounds》2002,38(11):1342-1347
The three-component reaction of acetaldehyde, cyanothioacetamide, and malononitrile results in 6-amino-3,5-dicyano-4-methylpyridine-2(1H)-thione. The latter reacts with different chemical reagents to afford new substituted isoquinolines and their fused derivatives, which show high fungicidal and bactericidal activities. 相似文献
3.
Cycloalkylidenemalononitriles couple with various diazonium salts to yield the corresponding cycloalkeno[c]pyridazines, which react with trichloroacetonitrile to give the 1,8-alkanopyrido[3,4-d]pyridazines. The reaction of cycloalkenopyridazines with DMF dimethylacetal gives enamine derivatives, which can be converted to 1,8-alkanopyrido[3,4-d]pyridazines via treating with hydrazine hydrate or aromatic amines. Substituted cycloalkenopyridines react with diazoaminobenzene to afford the corresponding 1,8-alkanopyridopyridazines. 相似文献
4.
Hani Moubasher Amani Elkholy May Sherif Mariam Zahran Sherif Elnagdy 《Molecules (Basel, Switzerland)》2022,27(8)
Fungal–bacterial co-culturing is a potential technique for the production of secondary metabolites with antibacterial activity. Twenty-nine fungal species were screened in a co-culture with carbapenem-resistant Klebsiella pneumoniae at different temperatures. A temperature of 37 ° showed inhibition of bacterial growth. Antimicrobial susceptibility testing for K. pneumoniae was conducted to compare antibiotic resistance patterns before and after the co-culture. Genotypic comparison of the K. pneumonia was performed using next generation sequencing (NGS). It was shown that two out of five K. pneumoniae, with sequence type ST 101 isolates, lost bla-OXA48, bla-CTX-M-14, tir, strA and strB genes after the co-culture with Scopulariopsis brevicaulis fungus. The other three isolates (ST 383 and 147) were inhibited in the co-culture but did not show any changes in resistance. The total ethyl acetate extract of the fungal–bacterial co-culture was tested against K. pneumoniae using a disc diffusion method. The concentration of the crude extract was 0.97 mg/µL which resulted in total inhibition of the bacteria. Using chromatographic techniques, the purified compounds were identified as 11-octadecenoic acid, 2,4-Di-tert-butylphenol, 2,3-Butanediol and 9-octadecenamide. These were tested against K. pneumoniae using the well diffusion method at a concentration of 85 µg/µL which resulted in total inhibition of bacteria. The co-culture results indicated that bacteria under chemical stress showed variable responses and induced fungal secondary metabolites with antibacterial activities. 相似文献
5.
Experimental investigation of frictional noise and surface-roughness characteristics 总被引:3,自引:0,他引:3
An experimental investigation into the nature of the noise generated when a stylus travels over a frictional surface has been
carried out using several engineering materials. The relation between the sound pressure level (SPL) and surface roughness
under various contact loads was established. An acoustic device was designed and constructed to be used as a reliable tool
for measuring roughness. For each tested material, it has been found that the filtered noise signal within a certain spectrum
bandwidth contains a specified frequency at which the amplitude is maximum. This frequency was named the dominating frequency
and was found to be a material constant independent of surface roughness and contact load. It was also found that the dominating
frequency for a given material is proportional to the sonic speed in that material. 相似文献
6.
Yehya M. Elkholy 《Journal of heterocyclic chemistry》2008,45(4):1237-1241
7.
Fractional differential equations are widely applied in physics, chemistry as well as engineering fields. Therefore, approximating
the solution of differential equations of fractional order is necessary. We consider the quadratic polynomial spline function
based method to find approximate solution for a class of boundary value problems of fractional order. We derive a consistency
relation which can be used for computing approximation to the solution for this class of boundary value problems. Convergence
analysis of the method is discussed. Four numerical examples are included to illustrate the practical usefulness of the proposed
method. 相似文献
8.
9.
M.M. Elkholy 《Journal of luminescence》2010,130(10):1880-1892
Lithium borate (LiB) glasses in the system (100−x)B2O3-xLi2O with x=20, 30, 40, 50, 60 and 70 mol% were prepared. The glasses were doped with different concentrations of the order of 10−1, 10−2, 10−3, 10−4 and 10−5 of MgO and their thermoluminescent (TL) response was investigated. The irradiations were performed using γ rays from a 60Co source in the dose range from 0.1 to 25 kGy. The material displayed good sensitivity for γ-rays and intensity of TL signals is dependent on γ-ray dose and Li2O content. For each dose level and investigated temperature range (50-350 °C), exactly single isolated glow peak appears in the temperature range of 165-205 °C depending on both Li2O concentrations and time of exposure. The shape of the glow peak has altered significantly with increase in the gamma ray dose or Li2O concentrations. The glass composition with x=50 mol% doped with 10−3 mol% of MgO presented the best TL response. The results of the present study indicated that the recorded single and isolated high temperature peak is a good candidate for TL dosimetric investigations. This indicates that 50 B2O3-50Li2O-doped with 10−3 mol% of MgO is possibly used as materials for radiation dosimetry in the dose range of 0.1-20 kGy. 相似文献
10.
Synthesis of Some New Pyrazole,Pyrimidine, Pyridazine,and Their Fused Derivatives from 3‐Oxo‐3,N‐diphenylpropionamide
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Fathy M. Abdelrazek Yehia M. Elkholy Ali M. Salah Nagwa M. Abdelazeem Peter Metz 《Journal of heterocyclic chemistry》2014,51(3):824-829
The title compounds were obtained from the reactions of 3‐oxo‐3,N‐diphenylpropionamide 3 with dimethylformamide dimethylacetal followed by hydrazine to afford the pyrazole 7 , condensation with benzaldehyde followed by cyclocondensation with guanidine to afford the pyrimidine derivative 13 , condensation with active methylenes followed by azo coupling of the products followed by cyclization to afford the pyridazines 17a , 17b . The pyridazinone 17b was explored for the synthesis of some novel pyridazine‐fused heterocyclic compounds 19 , 21 , 24a , 24b , 24c , and 26 . All structures were proved via their elemental analyses and spectral data. 相似文献