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排序方式: 共有830条查询结果,搜索用时 15 毫秒
21.
Selim Rehab E. Ahmed Hanaa H. Abd-Allah Somia H. Sabry Gilane M. Hassan Rasha E. Khalil Wagdy K. B. Abouhashem Nehal S. 《Applied biochemistry and biotechnology》2019,189(1):284-304
Applied Biochemistry and Biotechnology - Acute kidney injury (AKI) is a rapid loss of renal function. It has high mortality rates. Still, renal replacement therapy is considered the best solution... 相似文献
22.
Seda Ünlü Göknur Yaşa Atmaca Fikriye Tuncel Elmalı Ali Erdoğmuş 《Photochemistry and photobiology》2023,99(5):1233-1239
Although the sonophotodynamic method has an effective therapeutic outcome for anticancer treatment compared with the photodynamic method, there are not enough related studies in the literature and this study aims to contribute to the development of sonophotodynamic studies. For this purpose, the Schiff base substituted silicon phthalocyanines were designed and synthesized as effective sensitizer candidates and the photophysicochemical and sonophotochemical features of the phthalocyanines were examined to increase singlet oxygen efficiency. The calculated ΦΔ values indicate that the contribution of substituent groups improved the production of singlet oxygen compared with silicon (IV) phthalocyanine dichloride (SiPcCI2) and also the sonophotochemical applications increased the singlet oxygen yields. The ΦΔ values (ΦΔ = 0.76 for axially bis-{4-[(E)-(pyridin-3-ylimino)methyl]phenol} substituted silicon (IV) phthalocyanine ( 2a ), 0.68 for axially bis-4-[(E)-{[(pyridin-3-yl)methyl]imino}methyl]phenol substituted silicon (IV) phthalocyanine ( 2b ) in photochemical study) reached to ΦΔ = 0.98 for 2a , 0.94 for 2b in sonophotochemical study. This article will enrich the literature on increasing singlet oxygen yield. 相似文献
23.
A suite of polymers were evaluated for their suitability as viable substrate materials for microchip electrophoresis applications, which were fabricated via replication technology. The relevant physiochemical properties investigated included the glass transition temperature (T(g)), UV-vis absorption properties, autofluorescence levels, electroosmotic flow (EOF) and hydrophobicity/hydrophilicity as determined by sessile water contact angle measurements. These physiochemical properties were used as a guide to select the proper substrate material for the intended microchip electrophoretic application. The T(g) of these polymers provided a guide for optimizing embossing parameters to minimize replication errors (REs), which were evaluated from surface profilometer traces. RE values ranged from 0.4 to 13.6% for the polymers polycarbonate (PC) and low-density polyethylene (LDPE), respectively. The absorption spectra and autofluorescence levels of the polymers were also measured at several different wavelengths. In terms of optical clarity (low absorption losses and small autofluorescence levels), poly(methyl methacrylate), PMMA (clear acrylic), provided ideal characteristics with autofluorescence levels comparable to glass at excitation wavelengths that ranged from 488-780 nm. Contact angle measurements showed a maximum (i.e., high degree of hydrophobicity) for polypropylene (PP), with an average contact angle of 104 degrees +/-3 degrees and a minimum exhibited by gray acrylic, G-PMMA, with an average contact angle of 27 degrees +/-2 degrees. The EOF was also measured for thermally assembled chips both before and after treatment with bovine serum albumin (BSA). The electrophoretic separation of a mixture of dye-labeled proteins including; carbonic anhydrase, phosphorylase B, beta-galactosidase, and myosin, was performed on four different polymer microchips using laser-induced fluorescence (LIF) excitation at 632.8 nm. A maximum average resolution of 5.04 for several peak pairs was found with an efficiency of 6.68 x 10(4) plates for myosin obtained using a BSA-treated PETG microchip. 相似文献
24.
The first asymmetric synthesis of ethyl 4-aryl-3-azido-2-hydroxy-2-methyl-4-oxobutanoates via a cinchona organocatalyst induced aldol addition of α-azido ketones to ethyl pyruvate has been developed. The coupling reaction under optimized conditions was carried out to furnish tetrafunctionalized synthons with enantioselectivities of up to 91:9 and enriched diastereoselectivities of up to 95:5 (syn:anti). 相似文献
25.
M. Sh. Ramadan S. A. Senior G. M. Nabil E. A. Hamed 《Journal of Dispersion Science and Technology》2013,34(12):1752-1760
Reaction rate for alkaline hydrolysis of the substrates 3,5-dinitro-2-chloro benzotriflouride (DNCBTF) (1) at 30°C and 2,4-dinitrochloro benzene (DNCB) (2) at 50°C separetely with NaOH as nucleophile is carried out spectrophotometrically in mixed aqueous-acetonitrile solvents. In each system, cationic surfactant as dodecyltrimethyl ammonium bromide (DoTAB), or anionic one as sodium dodecyle sulfate (SDS) is used in wide range of concentrations to study the effect of micelle on the reaction rate. The micellar effect is explained in term of modified pseudo phase ion exchange model. Pseudo first order rate constant, kobs is obtained for each of the nucleophile and for both substrates 1 and 2 at all range of XAN · kobs at given [OH?] and in presence of any substrate is found to increase with the increase of DoTAB,while decrease with the increase of SDS as micellar phases. Critical micelle concentrations (CMCs) in similar trend are observed to increase in DoTAB while decrease in SDS systems by increasing acetonitrile (AN) content. Micellar binding constant (KS) between any type of given substrate and the formed micelle, is found to decrease in presence of DoTAB and increase in SDS micellar phases by increasing AN content. Finally, the ratios between pseudo first order rate constants for hydrolysis in micellar phase kM to that in the bulk phase kw for DoTAB and SDS systems are found to be greater than and smaller than unity respectively at any given XAN where the data indicated for (1) is always higher than those for (2). The results concluded that micelle DoTAB is working as a catalyst for the reaction rate, while that for SDS is considered as an inhibitor. 相似文献
26.
M. S. A. Abdel-Mottaleb E. Hamed M. Saif Hoda S. Hafez 《Journal of inclusion phenomena and macrocyclic chemistry》2018,92(3-4):319-327
This paper addresses modelling the nature of interactions between β-CD and some coumarins including recently reported novel sulphur analogues to form inclusion complexes of appealing medicinal, photochemical and photophysical properties. The binding energy and the total stabilization energy (EONIOM) are used to confirm the most favorable inclusion complex structure. Thermodynamic parameters reveal exothermic inclusion reaction in gas phase. Thermal stability of fluorescent enzyme substrate of coumarin nucleus increases in the order: gas?<?cyclohexane?<?water, indicating better stability in water. Furthermore, molecular characteristics such as optimized geometries, MO’s and electrostatic potential energy map surfaces and energies are reported and correlated with some reactivity indices. Our results validated the experimentally available data reported in the literature. Inclusion complexes of β-CD with coumarins should result in improving its laser efficiency in environmentally benign aqueous medium. 相似文献
27.
Sima Ahmadi Mohammad Taghi Hamed Mosavian Somayeh Heydari 《Journal of the Iranian Chemical Society》2018,15(11):2605-2614
A rapid and simple approach for the preconcentration and determination of catechin from pistachio green hull samples has been proposed by surfactant-assisted dispersive liquid–liquid microextraction followed by UV–Vis spectrophotometry (SADLLME/UV–Vis). This method involved the formation of a catechin complex with cetylpyridinium chloride (CPC) as cationic surfactant, and subsequently, DLLME was applied to extract the catechin–CPC complex into chloroform. Different parameters affected the extraction efficiency were optimized by central composite design (CCD) and response surface methodology (RSM). In optimum condition, the calibration curve was linear in the range of 0.4–5 µg mL??1 of catechin with correlation coefficient of 0.9982. The relative standard deviation based on five replicated analyses of 1 µg mL??1 catechin was 1.85%. The proposed method was successfully applied for preconcentration and determination of trace amounts of catechin in pistachio hull samples. 相似文献
28.
Hamed Nosrati Marziyeh Salehiabar Elahe Attari Soodabeh Davaran Hossein Danafar Hamidreza Kheiri Manjili 《应用有机金属化学》2018,32(2)
We report the synthesis of iron oxide magnetic nanoparticles (IONPs) coated with various natural amino acids (AAs) using a one‐pot reaction in an aqueous medium. Several AAs, which contained hydrophilic and hydrophobic groups, were selected to study their effects on size, morphology and toxicity of IONPs. Functionalized IONPs were characterized using X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and scanning and transmission electron microscopies. Furthermore, vibrating sample magnetometry analysis shows these nanoparticles have excellent magnetic properties. Cellular toxicity of IONPs was also investigated on HFF2 cell lines. The AA‐coated IONPs are non‐toxic and biocompatible. Natural AA‐coated IONPs show a potential for their development in in vitro and in vivo biomedical fields due to their non‐toxicity, good ζ‐potential and related small size and narrow size distribution. 相似文献
29.
30.
Sabry A. El-Korashy 《Monatshefte für Chemie / Chemical Monthly》2002,133(3):333-343
Summary. Solid crystalline calcium silicate hydrate (I) synthesized from equimolar amounts of Ca and Si under hydrothermal conditions
at 120°C shows cation exchange properties towards divalent metal cations such as Ni, Cu, Cd, or Hg. It also exhibits caesium
selectivity in the presence of Na+. The exchange capacity and selectivity of the solid can be increased by 10 and 28%, respectively, upon substitution of 0.01 mol
of the Ca2+ in its structure by Na+. The ability of metal cation uptake by the solid was found to obey the order Ni2+ > Hg2+ > Cu2+ > Cd2+. The different affinities of calcium silicate hydrate (I) towards these ions can be used for their separation from solutions
and also in nuclear waste treatment. The mechanism of the exchange reaction is discussed.
Received June 11, 2001. Accepted September 10, 2001 相似文献