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71.
1,4-Butanediol has been used as the hydrogen donor in transfer hydrogenation reactions. The equilibrium is driven by the formation of gamma-butyrolactone, and the diol is therefore not required in excess. 相似文献
72.
Many researchers have shown that plant-derived polyphenolic compounds are helpful nutraceuticals in restraining various disorders such as neoplastic diseases. In this study two linear furanocoumarins, aviprin and aviprin-3″-O-D-glucopyranoside (A3G), were isolated from methanol extract of Prangos uloptera roots. The evaluation of free radical scavenging capacity of the compounds showed that aviprin is a more effective antioxidant than A3G with RC50 of 0.54?mg?mL?1. The biological and antiproliferative activities of the furanocoumarins were examined using human cervical carcinoma HeLa cell line and LNCaP prostatic cell line. Cell membrane integrity and cell viability were evaluated by measuring trypan blue exclusion assay and reduction of the tetrazolium blue compound, respectively. Treating the LNCaP cell line with various concentrations of the furanocoumarins showed that IC?? of aviprin and A3G were 0.4 and 6.6?mg?mL?1, whereas their CC50 values were 0.7 and 11?mg?mL?1, respectively. These results indicated that 42.7% of LNCaP cells were not dead by necrosis. Treating the HeLa cells by the furanocoumarins showed the greater sensitivity of the HeLa cell line than the LNCaP cell line. A morphological analysis and the study of DNA fragmentation provided further some evidence for the inhibition of the LNCaP cell line via apoptosis induction. 相似文献
73.
Mohammad Ali Zolfigol Vahid Khakyzadeh Ahmad Reza Moosavi-Zare Abdolkarim Zare Seyedeh Bahareh Azimi Zhila Asgari Alireza Hasaninejad 《Comptes Rendus Chimie》2012,15(8):719-736
In this work, some novel sulfonic acid functionalized imidazolium salts (SAFIS), as a new category of ionic liquids, are synthesized by eco-friendly and simple procedures, and used as highly efficient and reusable catalysts to promote the following one-pot multicomponent organic transformations under solvent-free conditions: (i) the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes from β-naphthol (2 eq.) and arylaldehydes (1 eq.), (ii) the preparation of tetrahydrobenzo[a]xanthene-11-ones from β-naphthol, arylaldehydes and dimedone, and (iii) the synthesis of 1,8-dioxo-octahydroxanthenes from dimedone (2 eq.) and aromatic aldehydes (1 eq.). Environmentally benign, simple methodologies, easy workup procedure, clean reaction, short reaction time, high yield and easy preparation of the catalysts are some advantages of this work. 相似文献
74.
In the present paper, well-dispersed ZnO nano-, submicro- and microrods with hexagonal structure were synthesized by a simple low temperature hydrothermal process from zinc nitrate hexahydrate without using any additional surfactant, organic solvent or catalytic agent. The phase and structural analysis were carried out by X-ray diffraction (XRD), the morphological analysis was carried out by field emission scanning electron microscopy (FESEM) and the optical property was characterized by room-temperature photoluminescence (PL) spectroscopy. The results revealed the high crystal quality of ZnO powder with hexagonal (wurtzite-type) crystal structure and the formation of well-dispersed ZnO nano-, submicro- and microrods with diameters of about 50, 200 and 500 nm, and lengths of 300 nm, 1 μm and 2 μm, respectively, on a large-scale just using the different temperatures. Room-temperature PL spectrum from the ZnO nanorods reveals a strong UV emission peak at about 360 nm and no green emission band at ∼530 nm. The strong UV photoluminescence indicates the good crystallization quality of the ZnO nanorods. Room-temperature PL spectra from the ZnO submicro- and microrods reveal a weak UV emission peak at ∼400 nm and a very strong visible green emission at 530 nm, that is ascribed to the transition between VoZni and valence band. 相似文献
75.
Seyyed Mohsen Beladi‐Mousavi Bahareh Khezri Stanislava Matjkov Zdenk Sofer Martin Pumera 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(38):13474-13478
An electroadsorption technique similar to the ultrafast charging mechanism in supercapacitors is utilized to remove metals with different sizes and hydrophilicities from contaminated water using self‐propelled microswimmers. The swimmers carry graphite fibre or bismuth with a layered crystal structure providing high electrostatic double‐layer capacitances. Unlike previous methods, this electrochemical technique does not only utilize the surface of the swimmers, but due to the interlayer spacing of the graphite and bismuth, it is able to store metals in ≈400 layers, allowing removal and recovery of >50 ppm lithium in only 5 min. A larger interlayer distance between bismuth sheets allows the removal of bigger cations (sodium and calcium), expanding the application of this method to a large variety of natural elements. Finally, magnetic navigation of charged swimmers to an oxygen‐saturated media causes oxidation and thus immediate release of the metal ions from the swimmers. 相似文献
76.
Khalili Shahla Khorasani Saied Nouri Razavi Seyed Mohammad Hashemibeni Batool Tamayol Ali 《Applied biochemistry and biotechnology》2019,187(4):1193-1203
Applied Biochemistry and Biotechnology - Treatments of skin injuries caused by trauma and diseases are among the most considerable medical problems. The use of scaffolds that can cover the wound... 相似文献
77.
Equal channel angular pressing (ECAP) process was used to consolidate the Al65Cu20Ti15 metallic glass (AMG) reinforced Al matrix composite at high temperature. The matrix/reinforcement interfacial microstructure of the consolidated composite was studied using scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and transmission electron microscopy (TEM). It is demonstrated that the mutual diffusion of elements was occurred between the matrix and glass reinforcement during the consolidation process. The imposed severe plastic strains by the ECAP process affected the mutual diffusion and elemental distribution at the interface. Also, microstructural characterizations confirmed that no reaction products have been formed between the matrix and reinforcement particles. An illustrative model was presented to explain the atomic structure of matrix/reinforcement interface region. 相似文献
78.
M. Acanfora P. Gallo S. M. J. Razavi M. R. Ayatollahi F. Berto 《Physical Mesomechanics》2018,21(2):124-134
The present paper investigates the employment of coarse meshes in evaluating the T-stress with the displacement method. Several finite element analyses have been carried out with different mesh refinements and accuracies. Mode I and mixed mode I/II loadings have been considered in finite element analyses. Under mode I loading, single and double edge notched geometries have been considered, while plate with central crack has been considerd for mixed mode loading condition. The analyses are compared with the results by the well-nown stress based approach, and showed that the displacement method permits the evaluation of the T-stress with the employment of coarse meshes. By the way, several precautions must be taken when dealing with coarse and very coarse meshes. 相似文献
79.
Ahmed N Shirinfar B Youn IS Bist A Suresh V Kim KS 《Chemical communications (Cambridge, England)》2012,48(21):2662-2664
A new water-soluble and fluorescent imidazolium-anthracene cyclophane 1 effectively recognizes and differentiates the biologically important GTP and ATP in 100% aqueous solution of physiological pH 7.4. Fluorescence, (1)H-NMR spectra and ab initio calculations demonstrate that excimer formation and fluorescence enhancement occur upon GTP and ATP binding, respectively, through (C-H)(+)···A(-) hydrogen bond interactions. 相似文献
80.
Zanjanchi MA Razavi A 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2001,57(1):119-127
Diffuse reflectance spectroscopy has been used to investigate structural modification of mazzite zeolite subjected to calcination, acid leaching and acetylacetone treatments. Extra-framework aluminium species, formed upon expulsion of aluminium from the framework, are detected by DRS because they are involved in aluminium-oxygen charge transfer transitions. Impregnation of the calcined ammonium-exchanged and acid leached samples with ethanolic acetylacetone will convert the broadened 260-280 nm band of extra-framework aluminium with distorted symmetry to a distinct well-defined 285 nm band. The appearance of this band is due to the transformation of the aluminium atoms with a different coordination number to structures with highly ordered octahedral symmetry. Washing the acetylacetone treated samples with hot ethanol leads to extraction of some of the complexed aluminium. The presence of an extracted aluminium triacetylacetonate complex in the eluant is verified by the same spectrophotometer used in its conventional mode. This suggests that a dual DR and UV-VIS spectrophotometry is an appropriate approach to study such topics. 相似文献