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981.
We study by synchrotron small-angle x-ray scattering highly aligned lamellar phases of a zwitterionic surfactant, doped with monodisperse and spherical hydrophobic inorganic particles as a function of particle concentration. Analysis of the structure factor of the two-dimensional fluid formed by the particles in the plane of the bilayer gives access to their membrane-mediated interaction, which is repulsive, with a contact value of about 4kBT and a range of 14 angstroms. Systematic application of this technique should lead to a better understanding of the interaction between membrane inclusions. 相似文献
982.
Hoffman CR Baumann T Bazin D Brown J Christian G DeYoung PA Finck JE Frank N Hinnefeld J Howes R Mears P Mosby E Mosby S Reith J Rizzo B Rogers WF Peaslee G Peters WA Schiller A Scott MJ Tabor SL Thoennessen M Voss PJ Williams T 《Physical review letters》2008,100(15):152502
The neutron unbound ground state of (25)O (Z=8, N=17) was observed for the first time in a proton knockout reaction from a (26)F beam. A single resonance was found in the invariant mass spectrum corresponding to a neutron decay energy of 770_+20(-10) keV with a total width of 172(30) keV. The N=16 shell gap was established to be 4.86(13) MeV by the energy difference between the nu1s(1/2) and nu0d(3/2) orbitals. The neutron separation energies for (25)O agree with the calculations of the universal sd shell model interaction. This interaction incorrectly predicts an (26)O ground state that is bound to two-neutron decay by 1 MeV, leading to a discrepancy between the theoretical calculations and experiment as to the particle stability of (26)O. The observed decay width was found to be on the order of a factor of 2 larger than the calculated single-particle width using a Woods-Saxon potential. 相似文献
983.
The interest in the Camassa-Holm equation inspired the search for various generalizations of this equation with interesting properties and applications. In this Letter we deal with such a two-component integrable system of coupled equations. First we derive the system in the context of shallow water theory. Then we show that while small initial data develop into global solutions, for some initial data wave breaking occurs. We also discuss the solitary wave solutions. Finally, we present an explicit construction for the peakon solutions in the short wave limit of system. 相似文献
984.
Theodora-Venera Apostol Mariana Carmen Chifiriuc Constantin Draghici Laura-Ileana Socea Luminita Gabriela Marutescu Octavian Tudorel Olaru George Mihai Nitulescu Elena Mihaela Pahontu Gabriel Saramet Stefania-Felicia Barbuceanu 《Molecules (Basel, Switzerland)》2021,26(16)
The multi-step synthesis, physico-chemical characterization, and biological activity of novel valine-derived compounds, i.e., N-acyl-α-amino acids, 1,3-oxazol-5(4H)-ones, N-acyl-α-amino ketones, and 1,3-oxazoles derivatives, bearing a 4-[(4-chlorophenyl)sulfonyl]phenyl moiety are reported here. The structures of the newly synthesized compounds were confirmed by spectral (UV-Vis, FT-IR, MS, 1H- and 13C-NMR) data and elemental analysis results, and their purity was determined by RP-HPLC. The new compounds were assessed for their antimicrobial activity and toxicity to aquatic crustacean Daphnia magna. Also, in silico studies regarding their potential mechanism of action and toxicity were performed. The antimicrobial evaluation revealed that the 2-{4-[(4-chlorophenyl)sulfonyl]benzamido}-3-methylbutanoic acid and the corresponding 1,3-oxazol-5(4H)-one exhibited antimicrobial activity against Gram-positive bacterial strains and the new 1,3-oxazole containing a phenyl group at 5-position against the C. albicans strain. 相似文献
985.
We compute global log canonical thresholds of a large class of quasismooth well-formed del Pezzo weighted hypersurfaces in ?(a 0,a 1,a 2,a 3). As a corollary we obtain the existence of orbifold Kähler-Einstein metrics on many of them, and classify exceptional and weakly exceptional quasismooth well-formed del Pezzo weighted hypersurfaces in ?(a 0,a 1,a 2,a 3). 相似文献
986.
By connecting Blaschke products, unitary dilations of matrices, numerical range, Poncelet's theorem and interpolation, we extend and simplify Gau and Wu's work (Gau and Wu (2004) [10]). We look at Blaschke products' role in the Sendov conjecture. 相似文献
987.
Fotios Pasiouras Chrysovalantis Gaganis Constantin Zopounidis 《European Journal of Operational Research》2010
The purpose of the present study is the development of classification models for the identification of acquirers and targets in the Asian banking sector. We use a sample of 52 targets and 47 acquirers that were involved in acquisitions in 9 Asian banking markets during 1998–2004 and match them by country and time with an equal number of non-involved banks. The models are developed and validated through a tenfold cross-validation approach using two multicriteria decision aid techniques. For comparison purposes we also develop models through discriminant analysis. The results indicate that the multicriteria decision aid models are more efficient that the ones developed through discriminant analysis. Furthermore, in all the cases the models are more efficient in distinguishing between acquirers and non-involved banks than between targets and non-involved banks. Finally, the models with a binary outcome achieve higher accuracies than the ones which simultaneously distinguish between acquirers, targets and non-involved banks. 相似文献
988.
S. Voss M. Fonin L. Burova M. Burgert Y. S. Dedkov A. B. Preobrajenski E. Goering U. Groth A. R. Kaul U. Ruediger 《Applied Physics A: Materials Science & Processing》2009,94(3):491-495
The stability of single crystals and monolayers of Mn12 single molecule magnets under the influence of X-ray radiation and other possibly disruptive influences has been investigated
by means of synchrotron radiation. Clear evidence for radiation induced sample degradation was found for both single crystals
and monolayers. The comparison with spectra obtained after damaging the molecules by Ar+ sputtering, metal evaporation or water moistening indicates a possibility to distinguish between radiation damage and other
external influences. The results clarify some of the previous conflicting reports on the integrity of Mn12 molecules deposited on surfaces and are linked to the investigations aiming at studies of the electronic and magnetic properties
of individual Mn12 clusters. 相似文献
989.
Dan Rosu Constantin Ciobanu Liliana Rosu Carmen-Alice Teaca 《Applied Surface Science》2009,255(23):9453-9457
A polyurethane elastomer was synthesized starting from 4,4′ diphenylmethane diisocyanate and poly(ethyleneadipate)diol. Butylene glycol was used as chain extender. Surface properties after photo-degradation of the elastomer under the action of the radiation with λ > 300 nm was monitored by FT-IR spectroscopy and contact angle measurements. The quality of polymer surface was observed under optical microscope. The formation of photo-Fries rearrangement and Norrish II reaction products during irradiation was associated with the gloss loss (from 100% for non-irradiated sample to 27% after 200 h irradiation time) and modification of wettability. There were also found significant modifications with irradiation time of both the glass transition temperature (Tg decreases from 64 °C for non-irradiated sample to 53 °C after 200 h irradiation) and the swelling coefficient (an increase from 1.2% up to 2.5% is observed after 200 h irradiation). 相似文献
990.
Patrick Bentler Klaus Bergander Constantin G. Daniliuc Christian Mück‐Lichtenfeld Ravindra P. Jumde Anna K. H. Hirsch Ryan Gilmour 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11106-11110
Fluorinated motifs have a venerable history in drug discovery, but as C(sp3)?F‐rich 3D scaffolds appear with increasing frequency, the effect of multiple bioisosteric changes on molecular recognition requires elucidation. Herein we demonstrate that installation of a 1,3,5‐stereotriad, in the substrate for a commonly used lipase from Pseudomonas fluorescens does not inhibit recognition, but inverts stereoselectivity. This provides facile access to optically active, stereochemically well‐defined organofluorine compounds (up to 98 % ee). Whilst orthogonal recognition is observed with fluorine, the trend does not hold for the corresponding chlorinated substrates or mixed halogens. This phenomenon can be placed on a structural basis by considering the stereoelectronic gauche effect inherent to F?C?C?X systems (σ→σ*). Docking reveals that this change in selectivity (H versus F) with a common lipase results from inversion in the orientation of the bound substrate being processed as a consequence of conformation. This contrasts with the stereochemical interpretation of the biogenetic isoprene rule, whereby product divergence from a common starting material is also a consequence of conformation, albeit enforced by two discrete enzymes. 相似文献