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141.
2-(3-Chloro-2-formyl-1H-indol-1-yl) acetic acid, as a bifunctional formyl-acid, is prepared in three steps. This compound undergoes a one-pot, four-center, three-component Ugi reaction with primary amines and alkyl isocyanides. A series of novel substituted indoloketopiperazine derivatives are obtained in moderate to high yields. 相似文献
142.
Vishkaee Tehereh Sadigh Fazaeli Reza 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(9):1860-1860
Russian Journal of Physical Chemistry A - The name of the first author should read Tehereh Sadigh Vishkaee. 相似文献
143.
Nahid Talebi Burcu Ögüt Wilfried Sigle Ralf Vogelgesang Peter A. van Aken 《Applied Physics A: Materials Science & Processing》2014,116(3):947-954
Plasmonics is expected to play a key role in nanotechnology, leading to intriguing routes in many engineering and biological applications. Recently, it has been realized that toroidal resonances could be an alternative to electric and magnetic resonances, which have governed the innovation of plasmonic applications so far. In a previous contribution, we proved the existence of toroidal moments in an oligomeric void-plasmonic structure [1]. In this article, we investigate the role of topology and symmetry in decomposing the various dipolar, quadrupolar, and toroidal moments, using energy-filtering transmission electron microscopy supported by three-dimensional finite-difference time-domain method simulations. The consequences of changing the topology on the toroidal character are discussed by comparing results obtained from nanoholes forming heptamer and hexamer nanocavity systems that were drilled into a thin silver film. 相似文献
144.
Sepahvandi A Moztarzadeh F Mozafari M Ghaffari M Raee N 《Colloids and surfaces. B, Biointerfaces》2011,86(2):390-396
Photoluminescence (PL) property is particularly important in the characterization of materials that contain significant proportions of noncrystalline components, multiple phases, or low concentrations of mineral phases. In this research, the ability of biomimetic bone-like apatite deposition on the surface of titanium alloy (Ti6Al4V) substrates in simulated body fluid (SBF) right after alkaline-treatment and subsequent heat-treatment was studied by the inherent luminescence properties of apatite. For this purpose, the metallic substrates were treated in 5 M NaOH solution at 60 °C. Subsequently, the substrates were heat-treated at 600 °C for 1 h for consolidation of the sodium titanate hydrogel layer. Then, they were soaked in SBF for different periods of time. Finally, the possibility to use of PL monitoring as an effective method and early detection tool is discussed. According to the obtained results, it was concluded that the PL emission peak did not have any significant shift to the shorter or higher wavelengths, and the PL intensity increased as the exposure time increased. This research proved that the observed inherent PL of the newly formed apatite coatings might be of specific interest for histological probing and bone remodelling monitoring. 相似文献
145.
A simple and novel speciation method for the determination of volatile organic compounds of selenium (dimethylselenide (DMSe) and dimethyldiselenide (DMDSe) has been developed using a headspace hollow fiber protected liquid-phase microextraction (HS-HF-LPME) combined with capillary gas chromatography-mass spectrometry (GC-MS). The organic solvent impregnated in the pores and filled inside the porous hollow fiber membrane was used as an extraction interface in the HS-HF-LPME of the compounds. The effect of different variables on the extraction efficiency was studied simultaneously using an experimental design. The variables of interest in the HS-HF-LPME were sample volume, extraction time, temperature of sample solution, ionic strength, stirring rate and dwelling time. A Plackett-Burman design was performed for screening in order to determine the significant variables affecting the extraction efficiency. Then, the significant factors were optimized by a Box-Behnken design (BBD) and the response surface equations were derived. Under optimum conditions, preconcentration factors up to 1250 and 1170 were achieved for DMSe and DMDSe respectively. The detection limit and relative standard deviation (RSD) (n=5, c=50 μg L(-1)) for DMSe were 65 ng L(-1) and 4.8%, respectively. They were also obtained for DMDSe as 57 ng L(-1) and 3.9%, respectively. The developed technique was found to be applicable to spiked environmental and biological samples. 相似文献
146.
Nahid Kamelipour Afshin Mohsenifar Meisam Tabatabaei Tavoos Rahmani-Cherati Kamyar Khoshnevisan Abdolamir Allameh Majid M. Milani Saeid Najavand Batool Etemadikia 《Mikrochimica acta》2014,181(1-2):239-248
A dimeric organophosphorus hydrolase (OPH; EC 3.1.8.1; 72 kDa) was isolated from wild-type bacteria, analyzed for its 16s rRNA sequence, purified, and immobilized on gold nanoparticles (AuNPs) to form the transducer part of a biosensor. The isolated strain was identified as Pseudomonas aeruginosa. The AuNPs were characterized by transmission electron microscopy and localized surface plasmon resonance. Covalent binding of OPH to the AuNPs was confirmed by spectrophotometry, enzymatic activity assays, and FTIR spectroscopy. Coumarin 1, a competitive inhibitor of OPH, was used as a fluorogenic probe. The bioconjugates quench the emission of coumarin 1 upon binding, but the addition of paraoxon results in an enhancement of fluorescence that is directly proportional to the concentration of paraoxon. The gold-OPH conjugates were then used to determine paraoxon in serum samples spiked with varying levels of paraoxon. The method works in the 50 to 1,050 nM concentration range, has a low standard deviation (with a CV of 5.7–11 %), and a detection limit as low as 5?×?10?11 M. Figure
Coumarin 1, a competitive inhibitor of organophosphorus hydrolase, was used as a fluorogenic probe in the bioconjugates. The gold nanoparticles contained in the bioconjugates quench the emission of coumarin 1 upon binding, but the addition of paraoxon results in an enhancement of fluorescence leading to its detection. 相似文献
147.
Sepahvand M. Fazaeli R. Jameh-Bozorghi S. Niazi A. 《Russian Journal of Applied Chemistry》2019,92(1):141-149
Russian Journal of Applied Chemistry - In the present investigation, we synthesized copper (I) oxide nanoparticles (NPs) by the coprecipitation method. The obtained materials were characterized by... 相似文献
148.
Shahabadi Nahid Razlansari Mahtab Khorshidi Aref Zhaleh Hossein 《Research on Chemical Intermediates》2020,46(9):4257-4278
Research on Chemical Intermediates - Epirubicin loaded on magnetite-coated calcium ferrite conjugated folic acid (Fe3O4@CaFe2O4-FA@EPI) was synthesized and characterized using various techniques... 相似文献
149.
150.
Roya Mirzajani Nahid Pourreza Alireza R. Kiasat Samira S. Najjar 《International journal of environmental analytical chemistry》2013,93(7):800-810
Immobilization of β-cyclodextrin on Dowex resin as an insoluble polymeric matrix by covalent bond presents a new solid-phase medium for preconcentration of Pb (II) at trace level in environmental samples prior to its flame atomic absorption spectrometric determination. The method is based on the sorption of lead after passing on modified Dowex sorbent in a column. The effect of several parameters such as pH, flow rate of sample, eluent kind and volume was investigated. The sorption capacity of the matrix has been found to be 0.4996?mg?g?1 of adsorbent with the preconcentration factor of 250 for Pb (II). Nitric acid (3 M) as an eluent was sufficient to obtain quantitative recovery (>95%) for Pb (II). The optimum flow rate was 10?ml?min ?1. The calibration curve was linear in the range of (3–250?ng?mL?1) with a correlation coefficient of 0.9995. The limit of detection (LOD) based on three times the standard deviation of the blank was 1.37?ng?mL?1. The relative standard deviation (RSD) for determination of 10?ng?mL?1 and 100?ngmL?1 of Pb (II) was 3.00 % and 0.58 % (n?=?10), respectively. The method was successfully applied to determination of lead in some environmental samples such as tap water, river water, soil and rice. 相似文献