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991.
Juan?Jose?Del Coz DiazEmail author Paulino?Jose?Garcia Nieto Francisco?Jose?Suarez Dominguez 《Journal of Mathematical Modelling and Algorithms》2005,4(3):275-287
The aim of this work is to study the behaviour of a carbon/epoxi post housed in a canine tooth after endodontic treatment
in order to support the typical loads present during mastication. The three-D basic design of the dental piece consisting
of tooth + post was carried out with a three-dimensional parametric design program. We study the stresses and displacements
of the different elements of the dental piece under normal load conditions, and present the results and conclusions. 相似文献
992.
The folk questions in Lorentzian Geometry which concerns the smoothness of time functions and slicings by Cauchy hypersurfaces, are solved by giving simple proofs of: (a) any globally hyperbolic spacetime (M, g) admits a smooth time function whose levels are spacelike Cauchy hyperfurfaces and, thus, also a smooth global splitting if a spacetime M admits a (continuous) time function t then it admits a smooth (time) function with timelike gradient on all M.The second-named author has been partially supported by a MCyT-FEDER Grant, MTM2004-04934-C04-01.To Professor P.E. Ehrlich, wishing him a continued recovery and good health 相似文献
993.
We report a novel Fourier transform method for measuring two-photon excitation spectra. We demonstrate this method using simple dye molecules and discuss its applications in two-photon fluorescence microscopy and optimal control. This method facilitates an intuitive interpretation of recent control experiments in terms of tuning the nonlinear spectrum of the exciting laser source. 相似文献
994.
995.
Vertical movement of zirconia-yttria stabilized 2 mm balls is measured by a laser facility at the surface of a vibrated 3D granular matter under gravity. Realizations z(t) are measured from the top of the container by tuning the fluidized gap with a 1D measurement window in the direction of the gravity. The statistics obeys a Fermi-like configurational approach which is tested by the relation between the dispersions in amplitude and velocity. We introduce a generalized equipartition law to characterize the ensemble of particles which cannot be described in terms of a Brownian motion. The relation between global granular temperature and the external excitation frequency is established. 相似文献
996.
This paper presents a detailed numerical study of the heat exchange between two parallel plates with prescribed temperature gradients along the plates and a fluid circulating between them. The interplay between the bulk temperature, the heat flow and the Nusselt number has been clarified. 相似文献
997.
Manuel del Pino Jean Dolbeault Monica Musso 《Journal de Mathématiques Pures et Appliquées》2004,83(12):1405-1456
We consider the problem of finding positive solutions of Δu+λu+uq=0 in a bounded, smooth domain Ω in , under zero Dirichlet boundary conditions. Here q is a number close to the critical exponent 5 and 0<λ<λ1. We analyze the role of Green's function of Δ+λ in the presence of solutions exhibiting single and multiple bubbling behavior at one point of the domain when either q or λ are regarded as parameters. As a special case of our results, we find that if , where λ∗ is the Brezis-Nirenberg number, i.e., the smallest value of λ for which least energy solutions for q=5 exist, then this problem is solvable if q>5 and q−5 is sufficiently small. 相似文献
998.
In this paper we classify the p-local finite groups over p1+2+, the extraspecial group of order p3 and exponent p for odd p. This study reduces to the classification of the saturated fusion systems over p1+2+, which will be characterized by the outer automorphism group, the number of -radical subgroups and the automorphism group of each nontrivial -radical subgroup. As part of this classification, we obtain three new exotic 7-local finite groups.Partially supported by MCYT grant BFM2001-2035.Partially supported by MCYT grant BFM2001-1825.Both authors have been supported by the EU grant nr HPRN-CT-1999-00119.in final form: 1 October 2003 相似文献
999.
Bolognese A Correale G Manfra M Lavecchia A Novellino E Barone V 《Organic & biomolecular chemistry》2004,2(19):2809-2813
Microwave irradiation of a mixture of benzylidene-anilines and mercaptoacetic acid in benzene gives 1,3-thiazolidin-4-ones in very high yield (65-90%), whereas the same reaction performed through using the conventional method, at reflux temperature, requires a much longer time and gives a much lower yield (25-69%). This difference seems to be due to some intermediates and by-products formed during the conventional reaction. On the basis of 1H NMR studies, two different mechanisms, acting in benzene and in DMF, respectively, have been hypothesized for the thiazolidin-4-one system formation. 相似文献
1000.
Maqueda M Gálvez A Bueno MM Sanchez-Barrena MJ González C Albert A Rico M Valdivia E 《Current protein & peptide science》2004,5(5):399-416
After the discovery of bacteriocin AS-48, a 70-residue cyclic peptide produced by Enterococcus faecalis subsp. liquefaciens, some naturally-occurring cyclic proteins from bacteria have been reported. AS-48 is encoded by the 68-kb pheromone-responsive plasmid pMB2, and the gene cluster involved in production and immunity has been identified and sequenced. This peptide exerts a bactericidal action on sensitive cells (most of the Gram-positive and some Gram-negative bacteria). Its target is the cytoplasmic membrane, in which it opens pores, leading to the dissipation of the proton motive force and cell death, a mechanism similar to that proposed for the action of defensins or, most generally, cationic antibacterial peptides. This fact, together with its remarkable stability and solubility over a wide pH range, suggest that this bacteriocin could be a good candidate as a natural food preservative. The amino acid composition of purified AS-48 shows the absence of modified or dehydrated residues, making it clearly different from lantibiotics. Bacteriocin AS-48 also differs from defensins in that it does not contain cysteines and consequently no disulfide bridges, which makes is high stability even more remarkable. Composition analysis of AS-48 shows a high proportion of basic to acidic amino acids, conferring to this peptide a strong basic character, with an isoelectric point close to 10.5. Determination of the AS-48 structural gene DNA sequence, together with the sequences of AS-48 protease digestion fragments and mass spectrometry determinations, allowed us to determine unambiguously the cyclic structure of the molecule, being the first example of a posttranslational modification in which a cyclic structure arises from a "head-to-tail" linkage. We have solved the three-dimensional structure of AS-48 in solution, and it consists of a globular arrangement of five alpha-helices enclosing a compact hydrophobic core. Interestingly, the head-to-tail peptide link between Trp-70 and Met-1 lies in the middle of alpha-helix 5, which is shown to have a pronounced effect on the stability of the three-dimensional structure. Analysis of structure-function relationship allowed us to propose models to understand the aspects of the molecular function of AS-48. The purpose of this work is to review recent developments in our understanding about the biochemical and biological characteristics and structure of this unusual type of bacteriocin. 相似文献