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111.
Toropov Nikita A. Gladskikh Igor A. Parfenov Peter S. Vartanyan Tigran A. 《Optical and Quantum Electronics》2017,49(4):1-12
Optical and Quantum Electronics - In this paper, a theoretical analysis of figure of merit (FOM) of a surface plasmon resonance (SPR) sensor with a buffer layer of magnesium fluoride has been... 相似文献
112.
Tatiana E. Itina Nikita Shcheblanov 《Applied Physics A: Materials Science & Processing》2010,98(4):769-775
Effects of the ultrashort laser excitations of wide-band-gap materials are investigated. Single-, double-, and multiple-shot
cases are considered with a particular focus on the control over the transient reflectivity changes and the energy deposition
rate. We show that the history of laser excitations affects not only the ionization process and the final number of the conduction-band
electrons, but also determines the reflectivity time evolution and the rate of laser energy deposition into the target. Based
on the obtained calculation results, both thermal effects and structural modifications can be better controlled. 相似文献
113.
Veige AS Slaughter LM Lobkovsky EB Wolczanski PT Matsunaga N Decker SA Cundari TR 《Inorganic chemistry》2003,42(20):6204-6224
Deoxygenations of (silox)(3)WNO (12) and R(3)PO (R = Me, Ph, (t)Bu) by M(silox)(3) (1-M; M = V, NbL (L = PMe(3), 4-picoline), Ta; silox = (t)Bu(3)SiO) reflect the consequences of electronic effects enforced by a limiting steric environment. 1-Ta rapidly deoxygenated R(3)PO (23 degrees C; R = Me (DeltaG degrees (rxn)(calcd) = -47 kcal/mol), Ph) but not (t)Bu(3)PO (85 degrees, >2 days), and cyclometalation competed with deoxygenation of 12 to (silox)(3)WN (11) and (silox)(3)TaO (3-Ta; DeltaG degrees (rxn)(calcd) = -100 kcal/mol). 1-V deoxygenated 12 slowly and formed stable adducts (silox)(3)V-OPR(3) (3-OPR(3)) with OPR(3). 1-Nb(4-picoline) (S = 0) and 1-NbPMe(3) (S = 1) deoxygenated R(3)PO (23 degrees C; R = Me (DeltaG degrees (rxn)(calcd from 1-Nb) = -47 kcal/mol), Ph) rapidly and 12 slowly (DeltaG degrees (rxn)(calcd) = -100 kcal/mol), and failed to deoxygenate (t)Bu(3)PO. Access to a triplet state is critical for substrate (EO) binding, and the S --> T barrier of approximately 17 kcal/mol (calcd) hinders deoxygenations by 1-Ta, while 1-V (S = 1) and 1-Nb (S --> T barrier approximately 2 kcal/mol) are competent. Once binding occurs, significant mixing with an (1)A(1) excited state derived from population of a sigma-orbital is needed to ensure a low-energy intersystem crossing of the (3)A(2) (reactant) and (1)A(1) (product) states. Correlation of a reactant sigma-orbital with a product sigma-orbital is required, and the greater the degree of bending in the (silox)(3)M-O-E angle, the more mixing energetically lowers the intersystem crossing point. The inability of substrates EO = 12 and (t)Bu(3)PO to attain a bent 90 degree angle M-O-E due to sterics explains their slow or negligible deoxygenations. Syntheses of relevant compounds and ramifications of the results are discussed. X-ray structural details are provided for 3-OPMe(3) (90 degree angle V-O-P = 157.61(9) degrees), 3-OP(t)Bu(3) ( 90 degree angle V-O-P = 180 degrees ), 1-NbPMe(3), and (silox)(3)ClWO (9). 相似文献
114.
Suppose {f
1,...,f
m
} is a set of Lipschitz maps of
d
. We form the iterated function system (IFS) by independently choosing the maps so that the map f
i
is chosen with probability p
i
(
m
i=1
p
i
=1). We assume that the IFS contracts on average. We give an upper bound for the upper Hausdorff dimension of the invariant measure induced on
d
and as a corollary show that the measure will be singular if the modulus of the entropy
i
p
i
log p
i
is less than d times the modulus of the Lyapunov exponent of the system. Using a version of Shannon's Theorem for random walks on semigroups we improve this estimate and show that it is actually attainable for certain cases of affine mappings of . 相似文献
115.
Nikita A. Karpenko 《K-Theory》1998,13(4):305-330
116.
The binding free energy calculation of protein–ligand complexes is necessary for research into virus–host interactions and the relevant applications in drug discovery. However, many current computational methods of such calculations are either inefficient or inaccurate in practice. Utilizing implicit solvent models in the molecular mechanics generalized Born surface area (MM/GBSA) framework allows for efficient calculations without significant loss of accuracy. Here, GBNSR6, a new flavor of the generalized Born model, is employed in the MM/GBSA framework for measuring the binding affinity between SARS-CoV-2 spike protein and the human ACE2 receptor. A computational protocol is developed based on the widely studied Ras–Raf complex, which has similar binding free energy to SARS-CoV-2/ACE2. Two options for representing the dielectric boundary of the complexes are evaluated: one based on the standard Bondi radii and the other based on a newly developed set of atomic radii (OPT1), optimized specifically for protein–ligand binding. Predictions based on the two radii sets provide upper and lower bounds on the experimental references: kcal/mol. The consensus estimates of the two bounds show quantitative agreement with the experiment values. This work also presents a novel truncation method and computational strategies for efficient entropy calculations with normal mode analysis. Interestingly, it is observed that a significant decrease in the number of snapshots does not affect the accuracy of entropy calculation, while it does lower computation time appreciably. The proposed MM/GBSA protocol can be used to study the binding mechanism of new variants of SARS-CoV-2, as well as other relevant structures. 相似文献
117.
Viktor Pogorilyy Anna Plyutinskaya Nikita Suvorov Ekaterina Diachkova Yuriy Vasilev Andrei Pankratov Andrey Mironov Mikhail Grin 《Molecules (Basel, Switzerland)》2021,26(23)
In this work, we obtained the first selenium-containing chlorin with a chalcogen atom in exlocycle E. It was shown that the spectral properties were preserved in the target compound and the stability increased at two different pH values, in comparison with the starting purpurin-18. The derivatives have sufficiently high fluorescence and singlet oxygen quantum yields. The photoinduced cytotoxicity of sulfur- and selenium-anhydrides of chlorin p6 studied for the first time in vitro on the S37 cell line was found to be two times higher that of purpurin-18 and purpurinimide studied previously. Moreover, the dark cytotoxicity increased four-fold in comparison with the latter compounds. Apparently, the increase in the dark cytotoxicity is due to the interaction of the pigments studied with sulfur- and selenium-containing endogenous intracellular compounds. Intracellular distributions of thioanhydride and selenoanhydride chlorin p6 in S37 cells were shown in cytoplasm by diffusion distribution. The intracellular concentration of the sulfur derivative turned out to be higher and, as a consequence, its photoinduced cytotoxicity was higher as well. 相似文献
118.
119.
Nikita A. Karpenko 《Israel Journal of Mathematics》1999,111(1):125-141
LetA 1, …A n be central simple algebras over a fieldF. Suppose that we possess information on the Schur indexes of some tensor products of (some tensor powers of) the algebras. What can be said (in general) about possible degrees of finite field extensions ofF splitting the algebras? In Part I, we prove a positive result of that kind. In Part II, we prove a negative result. In Part III, we develop a general approach. 相似文献
120.
Barabash Nikita V. Belykh Vladimir N. 《The European physical journal. Special topics》2020,229(6-7):1071-1081
The European Physical Journal Special Topics - In this paper we study simple examples of non-autonomous maps having different changing in time chaotic attractors. We present the definition of... 相似文献