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991.
High-speed and scalable nickel-catalyzed cross-coupling of arylboronic acids with aryl carbamates and sulfamates is achieved by using sealed-vessel microwave processing. 相似文献
992.
Inhibition of Cu-amyloid-β by using bifunctional peptides with β-sheet breaker and chelator moieties
Jensen M Canning A Chiha S Bouquerel P Pedersen JT Østergaard J Cuvillier O Sasaki I Hureau C Faller P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(16):4836-4839
Breaking the mold: Inhibition of toxic amyloid-β (Aβ) aggregates and disruption of Cu-Aβ with subsequent redox-silencing of Cu have been considered promising strategies against Alzheimer's disease. The design and proof of concept of simple peptides containing a Cu-chelating/redox-silencing unit and an Aβ-aggregation inhibition unit (β-sheet breaker) is described (see scheme). 相似文献
993.
Ali Hossein Kianfar Mostafa Kazemi Boudani Mahmoud Roushani Mojtaba Shamsipur 《Journal of the Iranian Chemical Society》2012,9(4):449-453
The new [UO2L(CH3OH)] [where L?=?bis(salicylaldehyde)2,6-diiminopyridine (L1), bis(5-methoxysalicylaldehyde)2,6-diiminopyridine (L2), bis(5-bromosalicylaldehyde)2,6-diiminopyridine (L3), bis(5-nitrosalicylaldehyde)2,6-diiminopyridine (L4)] complexes were synthesized and characterized by IR, UV?Cvis and elemental analysis. Methanol solvent is coordinated to uranyl complexes. The electrochemical properties of the uranyl complexes were investigated by cyclic voltammetry in DMF solvent. Thermogravimetry and differential thermoanalysis of the uranyl complexes were carried out in the range of 20?C700?°C. The UO2L4 complex was decomposed in two and the others were decomposed in three stages. Up to 85?°C, the coordinated solvent was released then the Schiff base ligands were decomposed in one or two steps. Decomposition of synthesized complexes is related to the Schiff base characteristics. The thermal decomposition reaction is first order for the studied complexes. 相似文献
994.
El-Sayed M. E. Mostafa 《Numerical Functional Analysis & Optimization》2013,34(6):591-610
In this article, we consider the static output feedback problem for discrete-time systems when complete set of state variables is not available. It has been reported that quasi-Newton methods have substandard performance on this problem. A structured quasi-Newton method with trust region globalization is analyzed and studied for solving this problem. Moreover, the classical Anderson-Moore method is enhanced by using the trust region mechanism to ensure global convergence instead of the line search technique. The algorithms are tested numerically on test problems of engineering applications. 相似文献
995.
996.
Naser Fouladi Mohammadali A. Jafarizadeh Javad Fouladi Hadi Sabri 《Central European Journal of Physics》2013,11(4):526-530
We considered the characteristic features of SU(3) partial dynamical symmetry in the interacting boson model framework to show the relevance of such intermediate symmetry structure in the nuclear spectroscopy of the 160Dy nucleus. The predictions of SU(3)-PDS for the energy spectrum and the transition probabilities were compared with the most recent experimental data and an acceptable degree of agreement was achieved. 相似文献
997.
Khaled A. Ramadan Mostafa K. Seddeek Taher Sharshar Tarek Elnimr 《Isotopes in environmental and health studies》2014,50(2):235-256
Research of the effect of salinity on the fate of radionuclides has been focused on seas or estuarine systems while there is almost no information on marine environments with a salinity higher than that of sea water. The hypersaline Bardawil lagoon is a concentration basin, with evaporation exceeding precipitation. This study presents the characteristics of some environmental factors including salinity and their influence on the distribution of natural and artificial radionuclides in different compartments of the lagoon. The concentrations of 238U, 234Th, 228Ra and 137Cs in sediments show some degree of dependency on the water's salinity. Migration of these radionuclides in the lagoon's sediments must take place from high salinity to low-salinity regions. Cluster analysis revealed the data structure for sediment by separating 137Cs and 40K from 232Th, 226Ra, and 234Th and for sand by separating 40K from the other radioisotopes. 相似文献
998.
Morteza Ziyaadini Malek Taher Maghsoodlou Nourollah Hazeri Sayyed Mostafa Habibi‐Khorassani 《Heteroatom Chemistry》2013,24(1):84-89
A simple and efficient one‐pot three‐component reaction between hexamethyl phosphorous triamide and dimethyl acetylenedicarboxylate (DMAD) in the presence of CH‐acids, such as acetylacetone, 1,3‐indandione, dibenzoylmethane, anthrone, and N,N‐dimethylbarbituric acid, has been studied. In all cases, new and stable phosphorus ylides are obtained in excellent yields. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon–carbon partial double bond, resulting from conjugation of the ylide moiety with the adjacent carbonyl group. From the reaction of N,N‐dimethylbarbituric acid with DMAD in the presence of hexamethyl phosphorous triamide, a 1,4‐diionic organophosphorus compound is obtained. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 24:84–89, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21067 相似文献
999.
Structural phase transitions in the perovskite-like material [(CH4)12(NH3)2]CoCl4 have been observed using differential thermal scanning. The material shows an order-disorder transition at T 1 = 396 ± 5 K with entropy, (ΔS 1) = 12.8 J/mole/K. A "chain melting" transition with a major endothermic peak at T 2 = 337 ± 3 K and a minor one at T ′ = 316 ± 2 K, has total entropy ΔS = 28 J/mole/K. At low temperatures, the transitions at T 3 = 288 ± 3 K and at T 4 = 188 ± 3 K, have entropies of ΔS 3 = 14.4 J/mole/K and ΔS 4 = 2.6 J/mole/K respectively. AC magnetic susceptibility in the temperature range 78-290 K, in a magnetic field of 160 A/m and at a frequency of 320 Hz is presented. The results indicate changes in symmetry at 188 K. Dielectric permittivity has been studied as a function of temperature in the range 300-430 K and frequency range (60 Hz-100 kHz), confirming the observed transitions. The dielectric permittivity reflects rotational and conformational transition for the material. The variation of the real part of the conductivity with temperature is thermally activated with different activation energies in the range of ionic hopping. The temperature dependence of the dc conductivity and that of the ions hopping rate have indicated that the concentration of mobile ions is independent of temperature. The dependence of the conductivity on frequency follows the universal power law, <artwork name="GPHT31040ei1"> in the temperature range 340 K<T<390 K. Values 0 <s 1 <1 dominate at low frequency and correspond to translational hopping motion and values 1<s 2<2 dominate at high frequencies and correspond to well localized hopping and/or reorientational motion. For T > 396 K, the AC conductivity was fitted to <artwork name="GPHT31040ei2"> with 0<s<1. Comparison with the corresponding Cu-containing material is discussed. 相似文献
1000.
The Reaction of phenylmercury(II) acetate with salicylaldehyde morpholine N-thiohydrazone (H2smth) and 2-hydroxyacetophenone morpholine N-thiohydrazone (H2apmth) in dry ethanol under gentle refluxing condition form light yellow complexes [PhHg(Hsmth)] (1) and [PhHg(Hapmth)] (2) involving formation of Hg-S bond from the thiol form of the ligands after deprotonation of the SH proton. The structures of the complexes as determined by X-ray crystallography shows that the complex (1) has a distorted T-shaped geometry while the complex (2) adopts familiar linear coordination geometry. Complex (2) has two independent molecules comprising the asymmetric unit. Both the complexes form two-dimensional supramolecular assemblies due to a combination of weak intermolecular Hg····π and Hg····Hg interactions. The Hg····π and Hg····Hg distances are 3.937 and 4.0216(10) Å, respectively, possibly indicating weak mercuriophilic interactions. The luminescent properties of the complexes in solution and in the solid state at room temperature are also described. 相似文献