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排序方式: 共有489条查询结果,搜索用时 15 毫秒
1.
Najmedin Azizi 《Tetrahedron letters》2004,45(50):9233-9236
Under solvent-free reaction conditions and in the presence of solid LiClO4 a novel and mild protocol for the one-pot, three-component synthesis of primary α-amino phosphonates from an aldehyde, hexamethyldisilazane and a trialkyl phosphite is described giving high yields and having short reaction times. The same products are obtained in very low yields, when the three-component reaction is carried out under microwave irradiation and in the absence of solid LiClO4. Examples of some prepared 1-aryl-N,N′-bis(arylidene)methanediamines are also described. 相似文献
2.
Silver ion can perturb the Belousov-Zhabotinskii (B-Z) oscillating chemical reaction. Therefore, the B-Z oscillating system was applied in the determination of silver ion by using a platinum wire as an indicator electrode in the potentiometric method. The amplitude of the potentiometric oscillation increased linearly in proportion to [Ag+] in the range of 9.42 x 10(-6) M to 2.54 x 10(-4) M, with a correlation coefficient of 0.999 under the optimum conditions. The obtained LOD (2sigma) was 8.85 x 10(-6) M and the relative standard deviation (RSD) for five measurements of 1 x 10(-4) M silver ion was 5%. The influence of some potentially interference was also investigated. 相似文献
3.
Treatment of aliphatic and aromatic aldehydes with chiral amines and trimethylsilyl cyanide in the absence or in the presence
of Lewis acids (including lithium perchlorate) under solvent-free conditions afforded the corresponding α-aminonitriles in
good yields and with a diastereoselectivity of 68 to 86%.
Published in Russian in Zhurnal Organicheskoi Khimii, 2006, Vol. 42, No. 1, pp. 56–59.
The text was submitted by the authors in English. 相似文献
4.
Harris RK Kinnear KA Morris GA Stchedroff MJ Samadi-Maybodi A Azizi N 《Chemical communications (Cambridge, England)》2001,(23):2422-2423
The first use of silicon-29 diffusion-ordered NMR spectroscopy (DOSY) is reported, in a study of the speciation of aqueous silicates. 相似文献
5.
J. A. Azizi D. Dollimore P. J. Dollimore G. R. Heal P. Manley W. A. Kneller W. Jin Yong 《Journal of Thermal Analysis and Calorimetry》1993,40(2):831-847
In this study a relationship between the surface and textural properties of carbon blacks and the gasification process induced thermally in air is noted. A temperature jump method was used to follow the gasification in air and to establish the relevant Arrhenius parameters. This can be associated with the activity of ‘basal’ plane carbon atoms as well as ‘edge’ carbon atoms at the surface. This is based on a model of carbon black structure consisting of the irregular packing of small graphite carbon structures. The carbon black surface was measured using a single measurement of adsorption based essentially on the BET volumetric method. The carbon black surface had a rate of oxidation per unit are which clearly indicated that the lower area carbon blacks had a predominately active area of ‘edge’ atoms at the surface while the surface of the higher area carbon blacks had a predominate amount of ‘basal’ plane graphite carbon atoms. 相似文献
6.
Stephen E. Ullrich Esther Azizi Margaret L. Kripke 《Photochemistry and photobiology》1986,43(6):633-638
Abstract— After a single exposure of mice to UV radiation, their ability to generate a contact hypersensitivity (CHS) response to contact sensitizers applied epicutaneously to distant, unirradiated skin is severely impaired. It is not clear, however, if the classic delayed type hypersensitivity (DTH) reponse to exogenous antigens, injected into the subcutaneous (s.c.) space, can also be modulated by UV radiation. We report here that a single exposure of mice to UV radiation suppressed the induction of DTH to both erythrocyte and soluble protein antigens injected s.c., but did not suppress the elicitation of the response. The suppressive effect was abrogated by cyclophosphamide treatment. In addition, antigen-specific suppressor cells were found in the spleens of the mice with a decreased DTH response. Since the ability to mount a DTH response has been linked with the resistance to certain pathogenic microorganisms, we suggest that the suppression of DTH by UV radiation may have the potential to compromise host resistance to such infectious agents. 相似文献
7.
Leili Mohammadi Hossein Kamani Abolfazl Asghari Amin Mohammadpour Mohammad Golaki Abbas Rahdar George Z. Kyzas 《Molecules (Basel, Switzerland)》2022,27(19)
High concentrations of antibiotics have been identified in aqueous media, which has diminished the quality of water resources. These compounds are usually highly toxic and have low biodegradability, and there have been reports about their mutagenic or carcinogenic effects. The aim of this study was to apply zero-valent iron-oxide nanoparticles in the presence of hydrogen peroxide and the sonolysis process for the removal of the amoxicillin antibiotic from aqueous media. In this study, zero-valent iron nanoparticles were prepared by an iron chloride reduction method in the presence of sodium borohydride (NaBH4), and the obtained nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and vibrating-sample magnetometry (VSM). Then, using a Fenton-like process, synthetic wastewater containing 100 to 500 mg/L amoxicillin antibiotic was investigated, and the effects of different parameters, such as the frequency (1 and 2 kHz), contact time (15 to 120 min), the concentration of hydrogen peroxide (0.3%, 0.5%, and 6%), the dose of zero-valent iron nanoparticles (0.05, 0.1, 0.5 g/L), and pH (3, 5, 10) were thoroughly studied. A pH of 3, hydrogen peroxide concentration of 3%, ultrasonic-wave frequency of 130 kHz, zero-valent iron nanoparticles of 0.5 g/L, and contaminant concentration of 100 mg/L were obtained as the optimal conditions of the combined US/H2O2/nZVI process. Under the optimal conditions of the combined process of zero-valent iron nanoparticles and hydrogen peroxide in the presence of ultrasonic waves, a 99.7% removal efficiency of amoxicillin was achieved in 120 min. The results show that the combined US/H2O2/nZVI process could be successfully used to remove environmental contaminants, including antibiotics such as amoxicillin, with a high removal percentage. 相似文献
8.
Muhammad Nurhafizuddin Aziemah Azizi Long Chiau Ming Naeem Shafqat 《Molecules (Basel, Switzerland)》2022,27(14)
Cytochrome P450 oxidoreductase (POR) is a membrane-bound flavoprotein that helps in transferring electrons from its NADPH domain to all cytochrome P450 (CYP450) enzymes. Mutations in the POR gene could severely affect the metabolism of steroid hormones and the development of skeletal muscles, a condition known as Cytochrome P450 oxidoreductase deficiency (PORD). PORD is associated with clinical presentations of disorders of sex development, Antley and Bixler’s syndrome (ABS), as well as an abnormal steroid hormone profile. We have performed an in silico analysis of POR 3D X-ray protein crystal structure to study the effects of reported mutations on the POR enzyme structure. A total of 32 missense mutations were identified, from 170 PORD patients, and mapped on the 3D crystal structure of the POR enzyme. In addition, five of the missense mutations (R457H, A287P, D210G, Y181D and Y607C) were further selected for an in-depth in silico analysis to correlate the observed changes in POR protein structure with the clinical phenotypes observed in PORD patients. Overall, missense mutations found in the binding sites of POR cofactors could lead to a severe form of PORD, emphasizing the importance of POR cofactor binding domains in transferring electrons to the CYP450 enzyme family. 相似文献
9.
Mahmood Tajbakhsh Majid M. Heravi Abolfazl Hosseini Ahmad Shahrezaiee 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):773-776
Hantzsch 1,4-dihydropyriines were rapidly and efficiently oxidized using bismuth nitrate supported onto silica gel under microwave irradiation. 相似文献
10.
Hoda Keipour Mohammad A.Khalilzadeh Abolfazl Hosseini Afsaneh Pilevar Daryoush Zareyee 《中国化学快报》2012,23(5):537-540
Potassium fluoride doped natural zeolite was found to be an efficient and selective solid base catalyst for 1,4-Michael addition. The catalyst is easily prepared and the workup procedure simplified by simple filtration.All products were obtained in high yields as well as short reaction times. 相似文献