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81.
82.
83.
In this paper, we report the synthesis of hitherto unknown 5-haloethynyl and 5-(1,2-dihalo)vinyluracil nucleoside analogues of the anti-HIV AZT, and FLT drugs. The key step of those syntheses is a Pd(0) cross-coupling at C5 position under Sonogashira conditions. Finally, based on their in vitro anti-HIV activities and their cytotoxicity on PBM, CEM, and VERO cell lines, the best compounds were the 2′,3′-dideoxy-3′-fluoro-5-(bromo-2-iodo)vinyluridine (10b, EC50 of 0.6 μM), and the 3′-azido-2′,3′-dideoxy-5-(bromo-2-iodo)vinyluridine (16b, EC50 of 1.1 μM). 相似文献
84.
85.
Jerzy Bialkowski Karin Erdmann Andrzej Skowronski 《Transactions of the American Mathematical Society》2007,359(6):2625-2650
We introduce the class of deformed preprojective algebras of generalized Dynkin graphs (), (), , , and () and prove that it coincides with the class of all basic connected finite-dimensional self-injective algebras for which the inverse Nakayama shift of every non-projective simple module is isomorphic to its third syzygy .
86.
H. Möller M. Eickhoff M. Rapp H.W. Grueninger G. Krötz 《Applied Physics A: Materials Science & Processing》1999,68(4):461-465
Received: 11 September 1998 / Accepted: 19 October 1998 / Published online: 24 February 1999 相似文献
87.
J/ψ production at forward and midrapidity at the Relativistic Heavy-Ion Collider (RHIC) is calculated within a previously constructed
rate-equation approach accounting for both direct production and regeneration from c and
. The results are compared to the experimental data. The observed stronger suppression at forward rapidity can be qualitatively
explained by a smaller statistical regeneration component together with stronger cold nuclear matter induced suppression compared
to midrapidity. The χ
c
over J/ψ ratio and ψ′ over J/ψ ratio are also calculated. 相似文献
88.
N. Erdmann J.-V. Kratz N. Trautmann G. Passler 《Analytical and bioanalytical chemistry》2009,395(6):1911-1918
Micro-particles containing actinides are of interest for risk assessments of contaminated areas, nuclear forensic analyses,
and IAEA as well as Euratom safeguards programs. For their analysis, secondary ion mass spectrometry (SIMS) has been established
as the state-of-the-art standard technique. In the case of actinide mixtures within the particles, however, SIMS suffers from
isobaric interferences (e.g., 238U/238Pu, 241Am/241Pu). This can be eliminated by applying resonance ionization mass spectrometry which is based on stepwise resonant excitation
and ionization of atoms with laser light, followed by mass spectrometric detection of the produced ions, combining high elemental
selectivity with the analysis of isotopic compositions. This paper describes the instrumental modifications for coupling a
commercial time-of-flight (TOF)-SIMS apparatus with three-step resonant post-ionization of the sputtered neutrals using a
high-repetition-rate (kHz) Nd:YAG laser pumped tunable titanium:sapphire laser system. Spatially resolved ion images obtained
from actinide-containing particles in TOF-SIMS mode demonstrate the capability for isotopic and spatial resolution. Results
from three-step resonant post-ionization of bulk Gd and Pu samples successfully demonstrate the high elemental selectivity
of this process. 相似文献
89.
W. Fernengel H. Kronmüller M. Rapp Y. He 《Applied Physics A: Materials Science & Processing》1982,28(2):137-144
The isothermal crystallization of Fe40Ni40P14B6 (Metglas 2826) has been studied by transmission electron microscopy, using static observations of partially crystallized ribbons at room temperature and in situ dynamic registration of the crystallization process at elevated temperatures. At all temperatures crystallization takes place by the nucleation and growth of individual crystals. Analysis of the transformation kinetics allowed to determine the nucleation rates and the activation energy for crystal growth. The growth velocity of the crystal phase was found to be controlled by the diffusion coefficient of phosphorus in this alloy withD
0=2.5×1010±1cm{swu2}/s andQ=(3.4±0.15)eV. 相似文献
90.
Forces in the actin cytoskeleton are generated by small groups of nonprocessive myosin II motors for which stochastic effects are highly relevant. Using a cross-bridge model with the assumptions of fast power-stroke kinetics and equal load sharing between equivalent states, we derive a one-step master equation for the activity of a finite-sized ensemble of mechanically coupled myosin II motors. For constant external load, this approach yields analytical results for duty ratio and force-velocity relation as a function of ensemble size. We find that stochastic effects cannot be neglected for ensemble sizes below 15. The one-step master equation can be used also for efficient computer simulations with linear elastic external load and reveals the sequence of buildup of force and ensemble rupture that is characteristic for reconstituted actomyosin contractility. 相似文献