排序方式: 共有135条查询结果,搜索用时 10 毫秒
41.
42.
43.
Gholam Hossein Rounaghi Mohammad Hossein Arbab Zavvar Fatemeh Boosaeedi Razieh Sanavi Khoshnood 《Journal of inclusion phenomena and macrocyclic chemistry》2003,47(3-4):101-107
The complexation reactions betweenT1+, Hg2+ andAg+ metal cations with 18-Crown-6 (18C6)were studied in acetonitrile (AN)-methanol (MeOH) andbenzonitrile (BN)-methanol (MeOH) binary mixtures at differenttemperatures using the conductometric method. The conductance datashow that the stoichiometry of the complexes in most cases is1 : 1 (ML), but in the case of theTl+ cation, in addition to a1 : 1 complex, a 1 : 2 (ML2)complex is formed in solutions. A non-linear behaviourwas observed for the variation of log Kfof the complexes vs the composition of the binary mixed solvents. The stability of 18C6 complexes with T1+, Hg2+ and Ag+ cations is sensitive to solvent composition and in some cases, the stability order is changed with changingthe composition of the mixed solvents. The values of the thermodynamic parameters (Δ Hc°, Δ Sc°) for formation of 18C6-T1+, 18C6-Hg+2 and the 18C6-Ag+ complexes were obtained from the temperature dependence of the stability constants and the results show that the thermodynamics of the complexationreactions is affected by the nature and composition of the mixed solvents and in most cases, the complexes are enthalpy destabilized but entropy stabilized. 相似文献
44.
Ali Reza Gholipour Hassan Saydi Marzeih Sadat Neiband Razieh Sadat Neyband 《Structural chemistry》2012,23(2):367-373
The cooperative effects between T-shape stacking and hydrogen bond interactions in X-ben⊥pyr···H–F complexes were investigated
in this work. The results indicate that the electron-withdrawing/donating substituents decrease/increase the magnitude of
the binding energies compared to the unsubstituted X-ben⊥pyr···H–F (X = H) complex. The cooperative effects have been studied
while using the atoms in molecules (AIM) and natural bond orbital (NBO) methods, allowing us to evaluate the interplay between
T-shape stacking and hydrogen bond interactions. There are good relationships among binding energies, Hammett constants, geometrical
parameters, and the results of AIM and NBO analysis in X-ben⊥pyr···H–F complexes. 相似文献
45.
Loop-mediated isothermal amplification in conjunction with enzyme-linked immunosorbent assay (LAMP-ELISA) provides a sensitive, specific and cost-effective method for detection of etiological causes of infections. The present study developed a reliable LAMP-ELISA diagnostic kit for identification of Salmonella serogroup D strains and evaluated its potential use in the detection of Salmonella serovars Enteritidis and Typhi. The LAMP-ELISA assay used a serogroup D/A-specific primer set to amplify a region of the prt gene, followed by hybridization of the digoxigenin-labeled products to a highly specific oligonucleotide probe for exact identification of serogroup D serovars. Among the bacteria tested, a positive reaction was only observed for strains belong to Salmonella serogroup D. The detection limit of the LAMP-ELISA assay was 4 CFU per tube, which was lower than PCR-ELISA assay with the same target gene (50 CFU per tube). Finally, the technique was successfully applied to an artificially contaminated meat sample with a detection limit 103 CFU mL−1, which was 10 times more sensitive than PCR-ELISA. Overall, the LAMP-ELISA assay could be used as a sensitive alternative method to PCR-ELISA for the specific detection of Salmonella serogroup D serovars in routine food microbiology or clinical laboratories worldwide. 相似文献
46.
We describe here for the first time a new morphology of BiOF nanoparticles with a cotton‐like structure, made using a hydrothermal synthesis method. We also prepared heterogeneous nanosheets of BiOF@ZIF‐8 by a one‐pot synthesis under hydrothermal conditions. We demonstrate that in this method the morphology of BiOF and one‐pot synthesis conditions are the main factors for the preparation of the nanosheet BiOF@ZIF‐8. Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX), thermogravimetry‐differential thermal analysis (TG‐DTA), and BET surface area were used to characterize the samples prepared. XRD, SEM, and adsorption–desorption analysis showed that the structure of ZIF‐8 and BiOF form intact only in one‐pot synthesis of BiOF (with nano‐cotton‐like morphology) with Zn(NO3)3, while spectral techniques show the successful encapsulation of the sheet BiOF on ZIF‐8. Nanosheet BiOF@ZIF‐8 was found to be a highly efficient heterogeneous catalyst for the selective oxidation of alcohols. BiOF@ZIF‐8 could be reused several times although it got less active with recycling. 相似文献
47.
Majid M. Heravi Razieh Moradi Leyla Mohammadkhani Borzou Moradi 《Molecular diversity》2018,22(3):751-767
The Biginelli reaction, involving a three-component reaction of an aromatic aldehyde, urea and ethyl acetoacetate, has emerged as an extremely useful synthetic tool to organic chemists for the synthesis of 3,4-dihydropyrimidine-2-(1H)-ones and related heterocyclic compounds. In the past decades, the asymmetric variants of this reaction have been at the forefront of investigations in several research groups. In 2013, we highlighted the developments occurred in the asymmetric version of the Biginelli reaction. This review article focuses on the recent developments of asymmetric Biginelli reaction covers the literature going back to 2012. 相似文献
48.
Using first-principles approach, we theoretically study the effect of anion/cation vacancies on structural and electro-magnetic properties of zigzag AlN nanoribbons (ZAlNNRs). Calculations were performed using a full spin-polarized method within the density functional theory (DFT). Our findings shed light on how the edge states combined with vacancy engineering can affect electro-magnetic properties of ZAlNNRs. We found that depending on the nature and number of vacancies, ZAlNNRs can design as half-metal or semiconductor. Our results reveal a significant amount of spin magnetic moment for ZAlNNR with Al vacancies (VAl). These results may open new applications of AlN nano-materials in spintronics. 相似文献
49.
Elham?Shoghi Seyede?Zohreh?Mirahmadi-ZareEmail authorView authors OrcID profile Razieh?Ghasemi Matine?Asghari Mansour?Poorebrahim Mohammad-Hossein?Nasr-Esfahani 《Mikrochimica acta》2018,185(4):241
The authors introduce a new kind of surface artificial biomimetic receptor, referred to as aptameric imprinted polymer (AIP), for separation of biological macromolecules. Highly dispersed magnetic nanoparticles (MNPs) were coated with silica and then functionalized with methacrylate groups via silane chemistry. The aptamer was covalently immobilized on the surface of nanoparticles via a “thiol-ene” click reaction. Once the target analyte (bovine serum albumin; BSA) has bound to the aptamer, a polymer is created by 2-dimensional copolymerization of short-length poly(ethylene glycol) and (3-aminopropyl)triethoxysilane. Following removal of BSA from the polymer, the AIP-MNPs presented here can selectively capture BSA with a specific absorbance (κ) as high as 65. When using this AIP, the recovery of BSA from spiked real biological samples is >97%, and the adsorption capacity is as high as 146 mg g?1. In our perception, this method has a wide scope in that it may be applied to the specific extraction of numerous other biomolecules. 相似文献
50.
Robabeh Baharfar Razieh Azimi Zeinab Asdollahpour Hashem Bagheri 《Research on Chemical Intermediates》2018,44(2):859-871
Facile and efficient diastereoselective synthesis of trans-indolyldihydrofurans by three-component reaction of 3-cyanoacetyl indoles with various aromatic aldehydes and N-phenacylpyridinium bromides in presence of 1,1,3,3-N,N,N′,N′-tetramethylguanidine under solvent-free conditions is described. This ecofriendly protocol offers several advantages such as a cost-effective procedure with excellent yield, short reaction time, ease workup and product isolation, good functional group tolerance, and broad scope of usable substrates. The synthesized compounds were also evaluated for their antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay. 相似文献