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1.
Hybrid Laplace transform-finite element method to a generalized electromagneto-thermoelastic problem
A finite element method based on the Laplace transform technique is developed for a two-dimensional problem in electromagneto-thermoelasticity. The problem is in the context of the following generalized thermoelasticity theories: Lord–Shulman’s, Green–Lindsay’s, the Chandrasekharaiah–Tzou, as well as the dynamic coupled theory. The Laplace transform method is applied to the time domain and the resulting equations are discretized using the finite element method. The inversion process is carried out using a numerical method based on a Fourier series expansions. Numerical results compared with those given in literature prove the good performance of the used method. It is demonstrated that the Chandrasekharaiah–Tzou theory can be considered as an extension of Lord–Shulman’s, and the generalized heat conduction mechanism is completely different from the classical Fourier’s in essence. 相似文献
2.
HIV infection leads to progressive alterations of humoral immune functions, including B-cell hyperplasia, hypergammaglobulinemia,
elevated autoantibody titers, a poor response to neoantigens and mitogens, polyclonal B-cell activation, monoclonal gammopathies,
and a significant deterioration of the antigen-specific humoral response. There is also an important isotypic imbalance of
the antibody (Ab) response in the systemic compartment and a profound modification of mucosal immune functions. These abnormalities
may contribute to disease progression and development of opportunistic infections, despite the presence of serum-neutralizing
anti-HIV Abs. Equally important are the abnormal selection mechanisms of the Ab repertoire that seem to be responsible for
B-cell clonal deletions. The VH3 gene family, which encodes for approx 50% of immunoglobulins expressed by peripheral B-cells from normal adults, is underrepresented
in human monoclonal antibodies to HIV-1 and in the peripheral B-cells of AIDS patients. These abnormalities, together with
features of germinal center alteration, could be responsible for the clonal elimination of a subset of B-cells, and could
contribute to HIV pathogenesis. 相似文献
3.
Moncef Cossentini Bernard Deschamps Nguyen Trong Anh Jacqueline Seyden-Penne 《Tetrahedron》1977,33(4):409-412
Reaction of phosphonoester 2 and phosphononitrile 3 with chalcone and p-methoxychaleone in THF-t-BuOK at room temperature gives only the product resulting from CC double bond attack. The same reagents with benzalacetone lead to mixture of products resulting from CC double bond and carbonyl attack, though phosphine oxide 4 gives only the products of CC attack. Dypnone gives products of carbonyl attack with 3 and does not react with 2.These results are discussed in terms of perturbation theory: C4 attack increases with delocalization of the reagent's negative charge and lowering of the α-enone LUMO level. 相似文献
4.
A new total synthesis of Otanthus Maritima amide 1 was achieved from 6-trimetylsily N-tert-butyl sorbaldimine 6 in 76% global yield. The natural product 1 was obtained in three steps by condensation of 6 on thiophenal in the presence of catalytic amount of CsF (10%) in DMSO followed by oxidation and amidification of the corresponding intermediate. 相似文献
5.
6.
In this Note, we prove a theorem on the extension of a negative (or positive) plurisubharmonic current T (i.e. such that ) with condition on the slices with respect to some coordinates. This theorem generalizes a result proved by El Mir–Ben Messaoud relative to d-closed positive currents with a condition on slices. The method consists first of proving a Chern–Levine–Nirenberg inequality for a positive (or negative) psh current, which is a generalization of results obtained by Bedford–Taylor, Demailly and Sibony for d-closed positive currents. Also we prove an Oka type inequality for positive psh currents, thereby generalizing former results by Ben Messaoud–El Mir concerning positive currents with a negative . To cite this article: M. Toujani, H. Ben Messaoud, C. R. Acad. Sci. Paris, Ser. I 339 (2004). 相似文献
7.
Ikram Dhouib Philippe Guionneau Zakaria Elaoud 《Journal of Coordination Chemistry》2017,70(21):3585-3597
An organic-inorganic compound of tetraethylammonium dihydrogenarsenate bis(arsenic acid) salts of formula (NEt4)(H2AsO4)(H3AsO4)2, a potential new nonlinear optical material, was prepared by a slow evaporation technique and characterized by IR and Raman spectroscopy accomplished with DFT calculation and electrical-dielectrical measurements. The structure has been solved using direct method and refined by least-squares analysis. In this case, the structure consists of infinite parallel two-dimensional planes built of mutually H2AsO4?, H3AsO4 tetrahedra connected by strong O–H?O hydrogen bonding giving birth to trimers. The geometry, first hyperpolarizability and harmonic vibrational wavenumbers were calculated by means of density functional theory (DFT) with the B3LYP/6-31G(d) level of theory. Good consistency was found between the calculated and the experimental structure, IR, and Raman results. The first hyperpolarizability βtot of the title compound is about 1.75 times more than that of the reference crystal KDP. The complex impedance has been investigated in relation to the temperature and frequency ranges 297 and 373 K and 1 to 100 KHz, respectively. The conductivity temperature variation shows a typical Arrhenius-type behavior with a linear dependence on logarithm of conductivity. Transport properties in this material appear to be due to proton hopping mechanism. 相似文献
8.
Nahed Fakhfakh-Zouari Noomen Hmidet Anissa Haddar Safia Kanoun Moncef Nasri 《Applied biochemistry and biotechnology》2010,162(2):329-344
A keratinolytic enzyme (KerA1) secreted by a newly isolated Bacillus pumilus strain A1 cultivated in medium containing chicken feather meal was purified and characterized, and the gene was isolated
and sequenced. The molecular mass of the purified enzyme was estimated to be 34,000 Da by sodium dodecyl sulfate (SDS) polyacrylamide
gel electrophoresis and gel filtration. The optimum pH and temperature for the purified keratinase were 9.0 and 60 °C, respectively,
using keratin as a substrate. KerA1 showed a high stability towards nonionic surfactants. It was found to be relatively stable
toward the strong anionic surfactant (SDS). The deduced amino acid sequence of the keratinase KerA1 differs from both the
organic solvent tolerant protease of B. pumilus 115b and the dehairing protease of B. pumilus UN-31-C-42 by one and nine amino acids, respectively. These results suggest that this keratinase may be a useful alternative
and ecofriendly route for handling the abundant amount of waste feathers and for applications in detergent formulations. 相似文献
9.
Laila Manni Olfa Ghorbel-Bellaaj Kemel Jellouli Islem Younes Moncef Nasri 《Applied biochemistry and biotechnology》2010,162(2):345-357
Chitin is a polysaccharide found in abundance in the shell of crustaceans. In this study, the protease from Bacillus cereus SV1 was applied for chitin extraction from shrimp waste material of Metapenaeus monoceros. A high level of deproteinization 88.8% ± 0.4 was recorded with an E/S ratio of 20. The demineralization was completely achieved
within 6 h at room temperature in HCl 1.25 M, and the residual content of calcium in chitin was below 0.01%. 13C CP/MAS-NMR spectral analysis of chitin prepared by the enzymatic deproteinization of shrimp wastes was found to be similar
to that obtained by alkaline treatment and to the commercial α-chitin. The degree of N-acetylation, calculated from the spectrum,
was 89.5%. Chitin obtained by treatment with crude protease from B. cereus was converted to chitosan by N-deacetylation, and the antibacterial activity of chitosan solution against different bacteria
was investigated. Results showed that chitosan solution at 50 mg/mL markedly inhibited the growth of most Gram-negative and
Gram-positive bacteria tested. Furthermore, the antioxidant potential of the protein hydrolysates obtained during enzymatic
isolation of chitin was evaluated using various in vitro assays. All the samples exerted remarkable antioxidant activities. These results suggest that enzymatic deproteinization
of the shrimp shell wastes, using B. cereus SV1 protease, could be applicable to the chitin production process. 相似文献
10.
Junyong You Ulrich Reiter Miska M. Hannuksela Moncef Gabbouj Andrew Perkis 《Signal Processing: Image Communication》2010,25(7):482-501
Accurate measurement of the perceived quality of audio–visual services at the end-user is becoming a crucial issue in digital applications due to the growing demand for compression and transmission of audio–visual services over communication networks. Content providers strive to offer the best quality of experience for customers linked to their different quality of service (QoS) solutions. Therefore, developing accurate, perceptual-based quality metrics is a key requirement in multimedia services. In this paper, we survey state-of-the-art signal-driven perceptual audio and video quality assessment methods independently, and investigate relevant issues in developing joint audio–visual quality metrics. Experiments with respect to subjective quality results have been conducted for analyzing and comparing the performance of the quality metrics. We consider emerging trends in audio–visual quality assessment, and propose feasible solutions for future work in perceptual-based audio–visual quality metrics. 相似文献