Copper(II)-mediated N-cyclopropylation of pyridinols involving copper(II) acetate, pyridine, and NaHMDS under microwave conditions in a dry air atmosphere is described. 相似文献
In this paper, we establish several inequalities for some differantiable mappings that are connected with the Riemann-Liouville fractional integrals. The analysis used in the proofs is fairly elementar... 相似文献
We have investigated the superconducting properties of the Bi1.7 Pb0.3Sr2Ca2−xCexCu3O10+δ system with x=0.00, 0.02, 0.04, 0.08 and 0.1 by X-ray diffraction and magnetic susceptibility. The substitution of Ce for Ca has been found
to drastically change the superconducting properties of the system. X-ray diffraction studies on these compounds indicate
decrease in the c-parameter with increased substitution of Ce at Ca site and volume fraction of high Tc (2 : 2 : 2 : 3) phase decreases and low Tc phase increases. The magnetic susceptibility of this compound shows that the diamagnetic on set superconducting transition
temperature (onset) varies from 109 K to 51 K for x=0.00, 0.02, 0.04, 0.08 and 0.1. These results suggest the possible existence of Ce in a tetravalent state rather than a trivalent
state in this system; that is, Ca2+ → Ce4+ replacement changes the hole carrier concentration. Hole filling is the cause of lowering Tc of the system. 相似文献
In this paper the singularly perturbed initial boundary value problems for the nonlocal reaction diffusion system are considered. Unsing the iteration method and the comparison theorem, the existence, uniqueness and its asymptotic behavior of solution for the problem are studied. 相似文献
Research on Chemical Intermediates - We present a facile and environmentally benign protocol for synthesis of variously substituted imidazole derivatives via multicomponent condensation of benzil,... 相似文献
The aim of the proposed work was to develop robust hot-melt extrusion (HME) process for fabricating sustained-release mini-matrices (pellets) of a highly water-soluble drug, tramadol hydrochloride. The current work was designed to identify a formulation window with target functional performances such as streamlined processability and sustained-release profile with alcohol-resistant properties. HME was used to perform screening tests of various drug loadings and excipients to determine the acceptable limit of each independent component (critical material attributes, CMAs) in the Design of Experiment (DoE). It was observed that the ratio of hydrophobic (ethyl cellulose, EC; Compritol® ATO 888, C888) to hydrophilic (hydroxypropyl cellulose, HPC) components were critical factors evaluated using DoE. The processing temperature (105–175 °C) was identified as a critical process parameter. FTIR chemical imaging was used to assess the drug-matrix interaction, confirming a homogeneous drug distribution inside the polymer-lipid matrix system. SEM analysis and FTIR results were also in close agreement. Finally, a feasible formulation window containing EC, C888, and HPC in the ratios of 40:20:10 with the desired quality target product profile was successfully developed. Hydroalcoholic dissolution studies revealed safe and sustained-release of tramadol that resisted drug release variations for the first few hours in alcohol. The developed mini-matrices followed the Peppas–Sahlin model indicating a combination of Fickian diffusion and swelling mechanisms. Herein we conclude, a successful blueprint technology for the development of alcohol-resistant mini-matrices of tramadol hydrochloride via HME to provide once-a-day therapy for pain management, consequently reducing the dosing frequency.
The high spin states in N=80 139Pr have been investigated by in-beam γ-spectroscopic techniques following the reaction 130Te (14N, 5n) reaction at E=75 MeV, using a gamma detector array, consisting of seven 23% compton-suppressed high purity germanium detectors and a multiplicity
ball of fourteen bismuth germanate elements. Based on γ-γ coincidence data, the level scheme of 139Pr has been considerably extended up to 7.2 MeV excitation. Tentative spin-parity assignments are done for the newly proposed
levels on the basis of the DCO ratios corresponding to strong gates and the available information from the earlier light ion
experiments. 相似文献
A multilayered feed-forward ANN architecture trained using the error-back-propagation (EBP) algorithm has been developed for predicting whether a given nucleotide sequence is a mycobacterial promoter sequence. Owing to the high prediction capability (97%) of the developed network model, it has been further used in conjunction with the caliper randomization (CR) approach for determining the structurally/functionally important regions in the promoter sequences. The results obtained thereby indicate that: (i) upstream region of −35 box, (ii) −35 region, (iii) spacer region and, (iv) −10 box, are important for mycobacterial promoters. The CR approach also suggests that the −38 to −29 region plays a significant role in determining whether a given sequence is a mycobacterial promoter. In essence, the present study establishes ANNs as a tool for predicting mycobacterial promoter sequences and determining structurally/functionally important sub-regions therein. 相似文献
The values of incoherent scattering functions are determined experimentally for 145 keV gamma rays in elements Au, Ag and
Y at scattering angles 40°, 70° and 100°, using a x-ray gamma coincidence technique. The corresponding theoretical values
are obtained from the tabulations of Hubbellet al, and computed from the models of Jauch and Rohrlich and Shimizuet al. A comparison between the theoretical and experimental results showed that the non-relativistic approach adopted in the theory
of Shimizuet al is inapplicable to the present cases. A gross agreement is noticed between the present experimental results and the other
theoretical values. 相似文献
Clover detector has been used as a Compton polarimeter to measure the linear polarization of γ-rays produced in heavy ion
fusion reaction. The polarization sensitivity of the clover detector has been measured over γ-ray energies ranging from 386
to 1368 ke V. The E1 multipolarity of the 1117 keV transition in 99Rh has been established using this polarimeter. This has resulted in the assignment of negative parity to the band head at
3710 keV in 99Rh. 相似文献