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271.
A procedure for the analysis of90Sr,154Eu,237Np,239Pu,241Am and242−244Cm was developed. Separation was done with the separating agent, di-2(ethyl hexyl)-phosphoric acid (HDEHP), and results in
fractions containing the different elements to be analysed.90Sr analysis was done by analysing its daughter nuclide90Y, detected through the Cherenkov radiation emitted by this high energy β−-emitter.154Eu was detected using γ-spectrometry with a lower Compton background as a result of the removal of other fission products.241Am could also be detected with γ-spectrometry or together with242−244Cm with α-spectrometry. The long-lived radionuclides237Np and239Pu were detected using inductively coupled plasma mass spectrometry (ICP-MS). 相似文献
272.
Mohammed Ahmed Akkaif Nur Aizati Athirah Daud Abubakar Shaaban Mei Li Ng Muhamad Ali Sk Abdul Kader Dzul Azri Mohamed Noor Baharudin Ibrahim 《Molecules (Basel, Switzerland)》2021,26(7)
Clopidogrel is a widely-used antiplatelet drug. It is important for the treatment and prevention of coronary heart disease. Clopidogrel can effectively reduce platelet activity and therefore reduce stent thrombosis. However, some patients still have ischemic events despite taking the clopidogrel due to the alteration in clopidogrel metabolism attributable to various genetic and non-genetic factors. This review aims to summarise the mechanisms and causes of clopidogrel resistance (CR) and potential strategies to overcome it. This review summarised the possible effects of genetic polymorphism on CR among the Asian population, especially CYP2C19 *2 / *3 / *17, where the prevalence rate among Asians was 23.00%, 4.61%, 15.18%, respectively. The review also studied the effects of other factors and appropriate strategies used to overcome CR. Generally, CR among the Asian population was estimated at 17.2–81.6%. Therefore, our overview provides valuable insight into the causes of RC. In conclusion, understanding the prevalence of drug metabolism-related genetic polymorphism, especially CYP2C19 alleles, will enhance clinical understanding of racial differences in drug reactions, contributing to the development of personalised medicine in Asia. 相似文献
273.
Maniklal Shee Sk. Sheriff Shah Prof. N. D. Pradeep Singh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(62):14070-14074
This report presents the visible-light-assisted synthesis of aryl nitriles from easily accessible alcohols or methyl arenes in the presence of O2. Organic photoredox catalyst, 4CzIPN (1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene), induces single electron transfer (SET) from azide N3− and generates azide radical N3⋅.The photogenerated N3⋅ abstracts H atom from α-C−H bond of benzylic system, which provides aldehyde and hydrazoic acid (HN3) in situ. This reaction subsequently forms azido alcohol intermediate that transforms into nitrile with the assistance of triflic acid (Brønsted acid). A range of alcohols and methyl arenes successfully underwent cyanation at room temperature with good to excellent yields and showed good functional group tolerance. 相似文献
274.
Raju K. V. S. N. Begum Sk. S. Madhav B. T. P. Rao M. C. 《Journal of Applied Spectroscopy》2022,89(3):602-611
Journal of Applied Spectroscopy - Mesogenic 4-pentyl-4′-cyanobiphenyl (5CB) is a commonly used dielectric material for display devices and liquid crystal biosensors. A small concentration of... 相似文献
275.
Two new mononuclear copper (II) complexes [Cu(L)(H2O)Cl] (1) and [Cu(L)(H2O)(SCN)] (2) (HL = 2-[1-(2-dimethylamino-ethylimino)-ethyl]-phenol) have been synthesized and characterized in order to investigate their binding interaction with arsenate ions. Complexes 1 and 2 were synthesized by performing reaction of CuCl2·2H2O or CuCl2·2H2O/NH4SCN, respectively, with HL using Et3N as mild base in MeOH solution at room temperature, and characterized by employing a number of analytical techniques, for example, elemental analysis, molar electrical conductivity, FTIR, UV–Vis and mass spectrometry. Their structures, optimized at DFT/B3LYP/6-311G level, show that the copper atom in 1 and 2 exhibits a distorted square pyramidal geometry. In H2O/MeOH (3:1; v/v) solution, complexes 1 and 2 were examined for their binding affinity towards arsenate ions. The UV–Vis spectroscopic results specify that the arsenate group binds with 1 and 2 in 1:1 M ratio. The UV–Vis titration data were successfully utilized to calculate the binding constants of arsenate-bound Cu(II) complexes, and the values are found to be 1.723 × 104 M?1 and 2.161 × 104 M?1, corresponding to 1/AsO43? and 2/AsO43? assemblies, respectively. 相似文献
276.
ABSTRACT Inconsistencies exist in literature regarding the effect of prior austenite grain size (PAGS) on the extent and kinetics of bainite transformation. Attempts have been made in the present work to address these issues in a low-alloy carbide-free bainitic steel using dilatometry, over a range of PAGS. The bainite transformation kinetics in the above-mentioned conditions have been analysed quantitatively using established kinetic model to extract information related to the transformation mechanisms in such conditions. Greater obstruction from grain boundaries in fine-grained austenite restricts sheaves of bainite to develop completely and thereby reduces the volume fraction of bainite in comparison with coarse-grained austenite. Initial nucleation rate of bainite transformation increases with decreasing PAGS due to an increase in the nucleation site density. However, the maximum nucleation rate decreases consistently with decreasing PAGS due to gradual reduction in the autocatalytic factor. 相似文献
277.
Manpreet Singh Arijit Sengupta Sk. Jayabun Tejaswi Ippili 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(1):195-208
The extraction efficiency for thorium followed the trend: Cyanex-923 > Cyanex-272 > DHOA > TBP. In case of TBP and DHOA the extraction proceeded via ‘solvation mechanism’ through Th(NO3)4·2L, while for Cyanex-923 and Cyanex-272 it proceeded via ‘ion exchange’ mechanism through (Th(NO3)2·2L)2+. The extraction process followed slower kinetics while change in Gibb’s energy revealed the spontaneity of the process. These ionic liquid based systems were found to be radiolytically stable, highly efficient and selective for Th. Oxalic acid was found to be suitable for almost quantitative stripping of Th from extracted ionic liquid phase. 相似文献
278.
279.
M. Kondaiah K. Sreekanth D. Sravana Kumar Sk. Md. Nayeem D. Krishna Rao 《Journal of Thermal Analysis and Calorimetry》2014,118(1):475-483
The densities, ρ, and viscosities, η, of binary mixtures of ethylene glycol with formamide, N,N-dimethyl formamide and N,N-dimethyl acetamide, have been measured over the entire composition range at 308.15 K. From this experimental data, excess molar volume, \( V_{\text{m}}^{\text{E}} \) , deviation in viscosity, Δη, and excess Gibbs free energy of activation of viscous flow, \( \Delta G^{{ * {\text{E}}}}, \) have been determined. Negative values of \( V_{\text{m}}^{\text{E}} \) , Δη, and \( \Delta G^{{ * {\text{E}}}} \) are observed over the entire composition range in the mixtures studied. The observed negative values of various excess and deviation parameters are attributed to the existence of strong interactions, like dipole–dipole interactions, H-bonding between the carbonyl group of amide molecules, and hydroxyl group of glycol molecules, geometrical fitting of smaller molecules into the voids created by larger molecules in the liquid mixtures. The excess properties have been fitted to Redlich–Kister-type polynomial, and the corresponding standard deviations have been calculated. The derived partial molar volumes and excess partial molar volumes also support the \( V_{\text{m}}^{\text{E}} \) results. The experimental viscosity data of all of these liquid mixtures have been correlated with four viscosity models. 相似文献
280.
Non Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated with an aim of finding high electrocatalytic surface property for the faster electrode reactions. Electrodes were fabricated by electrodeposition on pure Al foil, from an electrolyte of Ni, Co, Fe salts. The optimum condition of electrodeposition were found out by a series of experiments, varying the chemistry of the electrolyte, pH valve, temperature, current and cell potential. Polarization study of the coated Ni-Co or Ni-Co-Fe alloy on pure Al was found to exhibit high exchange current density, indicating an improved electro catalytic surface with faster charge-discharge reactions at anode and cathode and low overvoltage. Electrochemical impedance studies on coated and uncoated surface clearly showed that the polarization resistance and impedance were decreased by Ni-Co or Ni-Co-Fe coating. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) studies confirmed the presence of alloying elements and constituents of the alloy. The morphology of the deposits from scanning electron microscope (SEM) images indicated that the electrode surface was a three dimensional space which increased the effective surface area for the electrode reactions to take place. 相似文献