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91.
Access to nonracemic amino ketones via a hydrozirconation/transmetalation/acylation sequence applied to Boc-protected 1-aminobut-3-enes is presented. This method was applied to the stereoselective synthesis of cyclic imines (or iminiums) which were diastereoselectively converted into 2-cis-substituted and 2,6-cis-disubstituted piperidines. The potential of this approach in the field of alkaloid synthesis was illustrated by the synthesis of (-)-coniine and (-)-indolizidine 209D. Furthermore, access to indolizidines bearing a quaternary center could also be envisioned through this strategy. 相似文献
92.
Mahdi Sadeghi Mohamadreza K. Bakht Leila Mokhtari 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):937-942
Radiolanthanide praseodymium-142 (T 1/2 = 19.12 h, E ?? ? = 2.162 MeV (96.3%), E?? = 1575 keV (3.7%)) due to its high ??-emission and low specific ??-emission could not only be a therapeutic radionuclide, but also a suitable radionuclide in order for biodistribution studies. Conventionally, 142Pr produces via 141Pr(n,??)142Pr reaction by irradiation in a low-fluence reactor and this study evaluates cyclotron reaction production of it. 142Pr excitation function via natLa(??,n)142Pr, 142Ce(p,n)142Pr, and natPr(d,p)142Pr reactions were calculated by TALYS-1.2 and EMPIRE-2.19beta codes, and with the data taken from the TENDL-2010 database. In addition, we compared them with the reported measurement by experimental data. Requisite thickness of targets was obtained by SRIM-2010 code for each reaction. The 142Pr production yield was evaluated with attention to excitation function and stopping power. Similar to reactor produced 142Pr; 141Pr impurity exists in cyclotron produced 142Pr while it could not be separated by chemical methods. Therefore, cyclotron and reactor produced 142Pr will be in carrier added form. 相似文献
93.
94.
The use of in situ generated N-thiocyanatosuccinimide with NH4SCN offers an efficient reagent system for the conversion of epoxides into their corresponding thiocyanohydrines in good to high yields.The major advantages of this method are as follows:use of cheap reagent,high regioselectivity,simple availability of reagent,ease of workup of the reaction. 相似文献
95.
Fares Mokhtari 《Mathematical Methods in the Applied Sciences》2013,36(2):196-207
In this paper, we prove existence and regularity of weak solutions for a class of nonlinear anisotropic parabolic problems in with locally integrable data. Our approach is based on the anisotropic Sobolev inequality, a smoothness, and compactness results. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
96.
M. Rafiee M. Soltani H. Mohammadi H. Mokhtari 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,63(3):473-482
The role of spin-orbit interaction arises from the Dzyaloshinskii-Moriya anisotropic antisymmetric interaction on the entanglement
transfer via an antiferromagnetic XXZ Heisenberg chain is investigated. From symmetrical point of view the XXZ Hamiltonian
with Dzyaloshinskii-Moriya interaction can be replaced by a modified XXZ Hamiltonian which is defined by a new exchange coupling
constant and rotated Pauli operators. The modified coupling constant and the angle of rotations depend on the strength of
Dzyaloshinskii-Moriya interaction. In this paper we study the dynamical behavior of the entanglement propagation through a
system which is consist of a pair of maximally entangled spins coupled to one end of the chain. The calculations are performed
for the ground state and the thermal state of the chain separately. In both cases the presence of this anisotropic interaction
make our channel more efficient. We show for large values of the strength of this interaction a large family of XXZ chains
becomes efficient quantum channels for whole values of anisotropy parameter in the region −2 ≤ Δ ≤ 2. 相似文献
97.
The first general method for the Suzuki-type cross-coupling of phenols with aryl boronic acids using dichloroimidazolidinedione (DCID) as a new reagent is presented. In the presence of DCID and Pd/metal–organic framework (MOF), coupling of aryl boronic acids with a wide range of phenols, was carried out smoothly in tetrahydrofuran (THF) at reflux conditions to afford the cross-coupling products in good to excellent yields. The structures of all compounds were corroborated by 1H- and 13C-NMR. A plausible mechanism for this type of reaction is proposed. 相似文献
98.
By direct integration of the Young-Laplace relation, a set of identities are presented for the axisymmetric sessile drops on flat and curved substrates. The geometrical parameters, including the apex curvature, the apex height, and the contact radius, are related by the identities. The validity of the identities is checked by various numerical solutions for drops on flat and curved substrates. 相似文献
99.
Indermeet Kohli Raheel Zubair Alexis B. Lyons Amanda F. Nahhas Taylor L. Braunberger Mohsen Mokhtari Eduardo Ruvolo Henry W. Lim Iltefat H. Hamzavi 《Photochemistry and photobiology》2019,95(6):1285-1287
Solar radiation is known to be a major contributor to the development of skin cancer. Most sunscreen formulations, including those with broad spectrum, offer minimal protection in long‐wavelength ultraviolet A1 (UVA1; 370–400 nm) and visible light (VL; 400–700 nm) domain. There is limited information regarding the impact of this broad waveband (VL + UVA1, 370–700 nm) on those with light skin. In this study, ten healthy adult subjects with Fitzpatrick skin phototypes I–III were enrolled. On day 0, subjects' lower back was exposed to a VL + UVA1 dose of 480 J cm?2. A statistically significant increase in erythema immediately after irradiation compared with subjects' baseline nonirradiated skin was observed. Clinically perceptible erythema with VL + UVA1 is a novel finding since the erythemogenic spectrum of sunlight has primarily been attributed to ultraviolet B and short‐wavelength ultraviolet A (320–340 nm). The results emphasize the need for protection against this part of the solar spectra and warrant further investigation. 相似文献
100.
Two magnetic regimes in doped ZnO corresponding to a dilute magnetic semiconductor and a dilute magnetic insulator 总被引:1,自引:0,他引:1
Behan AJ Mokhtari A Blythe HJ Score D Xu XH Neal JR Fox AM Gehring GA 《Physical review letters》2008,100(4):047206
Films of ZnO doped with magnetic ions Mn and Co and, in some cases, with Al have been fabricated with a very wide range of carrier densities. Ferromagnetic behavior is observed in both insulating and metallic films, but not when the carrier density is intermediate. Insulating films exhibit variable range hopping at low temperatures and are ferromagnetic at room temperature due to the interaction of the localized spins with static localized states. The magnetism is quenched when carriers in the localized states become mobile. In the metallic (degenerate semiconductor) range, robust ferromagnetism reappears together with very strong magneto-optic signals and room temperature anomalous Hall data. This demonstrates the polarization of the conduction bands and indicates that, when ZnO is doped into the metallic regime, it behaves as a genuine magnetic semiconductor. 相似文献