排序方式: 共有66条查询结果,搜索用时 15 毫秒
51.
Marziyeh E. Kenari Joshua I. Putman Ravi P. Singh Brandon B. Fulton Huy Phan Reem K. Haimour Key Tse Alain Berthod Carl J. Lovely Daniel W. Armstrong 《Molecules (Basel, Switzerland)》2021,26(1)
Twelve new azole compounds were synthesized through an ene reaction involving methylidene heterocycles and phenylmaleimide, producing four oxazoles, five thiazoles, and one pyridine derivative, and ethyl glyoxylate for an oxazole and a thiazole compound. The twelve azoles have a stereogenic center in their structure. Hence, a method to separate the enantiomeric pairs, must be provided if any further study of chemical and pharmacological importance of these compounds is to be accomplished. Six chiral stationary phases were assayed: four were based on macrocyclic glycopeptide selectors and two on linear carbohydrates, i.e., derivatized maltodextrin and amylose. The enantiomers of the entire set of new chiral azole compounds were separated using three different mobile phase elution modes: normal phase, polar organic, and reversed phase. The most effective chiral stationary phase was the MaltoShell column, which was able to separate ten of the twelve compounds in one elution mode or another. Structural similarities in the newly synthesized oxazoles provided some insights into possible chiral recognition mechanisms. 相似文献
52.
Research on Chemical Intermediates - Bisulfate-functionalized dicationic ionic liquid grafted with silica-coated nano-Fe3O4 (nano-[Fe3O4@SiO2@BDIL] or NFSBDI) was synthesized as a novel... 相似文献
53.
The binodal (solubility) curves and tie line data for ternary systems of (water + propionic acid + dichloromethane) at 91.3 kPa and T = (277.15, 284.15, and 294.15) K are reported. The binodal curve results were determined by cloud point measurements method. A simple titration method has been used for determining of the concentration of propionic acid in the both liquid phases at equilibrium. The results obtained were successfully correlated with the UNIQUAC activity coefficient model. The deviations between experimental and calculated compositions in both phases for the ternary system using this model are reported. The partition coefficients of propionic acid and the selectivity factor of dichloromethane for extracting of propionic acid from water were calculated and are reported. The phase diagrams for the ternary system studied including both the experimental and correlated tie lines are presented. 相似文献
54.
Ali Aghaei Mehdi Erfani Jazi Todd E Mlsna Mohammad Ali Kamyabi 《Journal of separation science》2019,42(18):3002-3008
Electromembrane extraction was used with high‐performance liquid chromatography for preconcentration and determination of ampicillin residues in cow milk. Ampicillin is transferred from an aqueous solution through a thin layer containing octan‐1‐ol, silver nanoparticles, and reduced graphene oxide which serves as a supported liquid membrane. Inside the fiber impregnated with supported liquid membrane mixture was filled 10 µL of an acceptor phase. Experimental parameters were optimized for extraction efficiency of ampicillin. Under the optimized conditions, the proposed method provided acceptable linear range (2–100 µg/L), satisfactory repeatability (RSD% < 7.1), low limit of detection (0.6 µg/L), and a high enrichment factor (295) corresponding to extraction recovery of 37%. Consequently, the proposed method was successfully applied for the determination of ampicillin residues in different cow milks. 相似文献
55.
Cavitation is a dynamic phenomenon that occurs in fluid flows when the local pressure is lower than the saturated vapor pressure at ambient temperature. The formation and collapse of cavitation bubbles leads to corrosion and pitting of metal surfaces. Considering the fact that damage to moving parts caused by cavitation has serious consequences it is important to be able to detect it. In this research an attempt is made to study the development of cavitation in globe valves using two different methods: characteristic diagrams and acoustic measurement. The results of the two methods are found to be in general agreement within acceptable levels of accuracy. 相似文献
56.
Chitosan (CS) was prepared from Artemia urmiana cyst shells using the same chemical process as described for the other crustacean species, with minor adjustments in the treatment conditions. The influence of modifications of the CS production process on the physiochemical and functional properties of the CS obtained was examined. The study results indicate that Artemia urmiana cyst shells are a rich source of chitin as 29.3-34.5% of the shell's dry weight consisted of this material. Compared to crab CS (selected as an example of CS from a different crustacean source) Artemia CS exhibited a medium molecular weight (4.5-5.7 x10(5) Da), lower degree of deacetylation (67-74%) and lower viscosity (29-91 centiposes). The physicochemical characteristics (e.g., ash, nitrogen and molecular weight) and functional properties (e.g., water binding capacity and antibacterial activity) of the prepared Artemia CSs were enhanced, compared to control and commercial samples, by varying the processing step sequence. 相似文献
57.
Abdollah Ardebili Mohammad Hassan Pouriayevali Sahar Aleshikh Marziyeh Zahani Mehdi Ajorloo Ahdieh Izanloo Abolghasem Siyadatpanah Hadi Razavi Nikoo Polrat Wilairatana Henrique Douglas Melo Coutinho 《Molecules (Basel, Switzerland)》2021,26(22)
The treatment of viral disease has become a medical challenge because of the increasing incidence and prevalence of human viral pathogens, as well as the lack of viable treatment alternatives, including plant-derived strategies. This review attempts to investigate the trends of research on in vitro antiviral effects of curcumin against different classes of human viral pathogens worldwide. Various electronic databases, including PubMed, Scopus, Web of Science, and Google Scholar were searched for published English articles evaluating the anti-viral activity of curcumin. Data were then extracted and analyzed. The forty-three studies (published from 1993 to 2020) that were identified contain data for 24 different viruses. The 50% cytotoxic concentration (CC50), 50% effective/inhibitory concentration (EC50/IC50), and stimulation index (SI) parameters showed that curcumin had antiviral activity against viruses causing diseases in humans. Data presented in this review highlight the potential antiviral applications of curcumin and open new avenues for further experiments on the clinical applications of curcumin and its derivatives. 相似文献
58.
Erfani Hamidreza Karadimitriou Nikolaos Nissan Alon Walczak Monika S. An Senyou Berkowitz Brian Niasar Vahid 《Transport in Porous Media》2021,140(1):421-435
Transport in Porous Media - Solute transport under single-phase flow conditions in porous micromodels was studied using high-resolution optical imaging. Experiments examined loading (injection of... 相似文献
59.
In continuation of our previous works on the application of (NH4)42[MoVI72MoV60O372(CH3COO)30(H2O)72], a Keplerate‐type giant‐ball nanoporous isopolyoxomolybdate, as a catalyst for the synthesis of heterocyclic compounds, in this paper, we report another application of this attractive catalyst in the synthesis of 2‐amino‐5‐oxo‐4,5‐dihydropyrano[3,2‐c]chromene‐3‐carbonitriles via a one‐pot three‐component reaction of 4‐hydroxycoumarin, aldehydes and malononitrile. The reactions occur in ethanol–water as solvent at room temperature and the process is operative with various aldehydes, giving the corresponding products in high yields. Other beneficial features of this protocol include short reaction times, simple work‐up and the recyclability and reusability of the catalyst for up to five consecutive runs. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
60.
B. Jazi M. Nejati A. Salehi 《International Journal of Infrared and Millimeter Waves》2006,27(11):1469-1495
By using the Fourier components of dielectric tensor elements of cold collisionless degenerate plasmas, the dispersion relation
of electromagnetic waves in a cylindrical metallic waveguide with a degenerate plasma column protected by an annular dielectric
layer are obtained. The permissible frequency regions for slow and fast waves in E-mode (TM) are presented. Furthermore, the
graph of cutoff frequency versus the radius of plasma column for the fast waves is investigated. In addition, the time growth
rate for excitation of symmetric slow E-modes (TM) by a thin annular relativistic electron beam (TAREB) is studied. The graph
of time growth rate respect to radius of dielectric layer and accelerating voltage are presented.
PACS No. 52.25. 相似文献