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91.
92.
In this paper we study the oscillatory properties for the eigenfunctions of some fourth-order eigenvalue problems, where the boundary conditions are irregular in the sense of the classification of [S. Janczewski, Oscillation theorems for the differential boundary value problems of the fourth order, Ann. of Math. 29 (1928) 521–542]. In this case, we show that these oscillatory properties are different from those of the Sturm–Liouville problem. 相似文献
93.
In this paper, we study the Riesz basis property and the problem of stabilization of two vibrating strings connected by a point mass with variable physical coefficients under a boundary feedback control acts at one extreme point and Dirichlet boundary condition on the other end. It is shown that the system has a sequence of generalized eigenfunctions which forms a Riesz basis for the state Hilbert space. By a detailed spectral analysis, it is proved that this hybrid system is asymptotically stable but not exponentially stable. 相似文献
94.
JPC – Journal of Planar Chromatography – Modern TLC - 相似文献
95.
Oliveira E Amara I Bellido D Odena MA Domínguez E Pagès M Goday A 《Journal of mass spectrometry : JMS》2007,42(11):1485-1495
Protein identification in systems containing very highly abundant proteins is not always efficient and usually requires previous enrichment or fractionation steps in order to uncover minor proteins. In plant seeds, identification of late embryogenesis abundant (LEA) proteins is often masked by the presence of the large family of storage proteins. LEA-proteins are predicted to play a role in plant stress tolerance. They are highly hydrophilic proteins, generally heat-stable, and correlate with dehydration in seeds or vegetative tissues. In the present work, we analyze the protein composition of heat-stable Arabidopsis thaliana seed extracts after treatment with trichloroacetic acid (TCA). The composition of the proteins that precipitate and those that remain in solution in 3% TCA was analyzed by two different approaches: 1D SDS-PAGE coupled to LC-ESI-MSMS analysis and a gel-free protocol associated with LC-MALDI-MSMS. Our results indicate that treating total heat-soluble extracts with 3% TCA is an effective procedure to remove storage proteins by selective precipitation and this fractionation step provides a soluble fraction highly enriched in Lea-type proteins. The analysis and determination of protein identities in this acid-soluble fraction by MS technology is a suitable system for large-scale identification of Lea-proteins present in seeds. 相似文献
96.
Jamel Ben Amara 《Mathematische Nachrichten》2012,285(1):42-46
Oscillation criteria for self‐adjoint fourth‐order differential equations were established for various conditions on the coefficients r(x) > 0, q(x) and p(x). However, most of these results deal with the case when limx → ∞∫x1q(s) ds < +∞. In this note we give a new oscillation criterion in the case when this condition is not fulfilled, in particular when q(x)↗ + ∞ (even with exponential growth). 相似文献
97.
Ghulam Murtza Anjum Weidong Du Rachel Klein Umme Amara Markus Huber‐Lang E. Marion Schneider Peter Wiegand 《Electrophoresis》2010,31(2):309-314
Forensic analysis of mitochondrial displacement loop (D‐loop) sequences using Sanger sequencing or SNP detection by minisequencing is well established. Pyrosequencing has become an important alternative because it enables high‐throughput analysis and the quantification of individual mitochondrial DNAs (mtDNAs) in samples originating from more than one individual. DNA typing of the mitochondrial D‐loop region is usually the method of choice if STR analysis fails because of trace amounts of DNA and/or extensive degradation. The main aim of the present work was to optimize the efficiency of pyrosequencing. To do this, 31 SNPs within the hypervariable regions I and II of the D‐loop of human mtDNA were simultaneously analyzed. As a novel approach, we applied two sets of amplification primers for the multiplexing assay. These went in combination with four sequencing primers for pyrosequencing. This method was compared with conventional sequencing of mtDNA from blood and biological trace materials. 相似文献
98.
M. Mekhnache A. Drici L. Saad Hamideche H. Benzarouk A. Amara L. Cattin J.C. Bernède M. Guerioune 《Superlattices and Microstructures》2011
ZnO thin films were deposited on glass, ITO (In2O3; Sn) and on ZnO:Al coated glass by spray pyrolysis. The substrates were heated at 350 °C. Structural characterization by X-ray diffraction (XRD) measurements shows that films crystallize in hexagonal structure with a preferential orientation along (0 0 2) direction. XRD peak-shift analysis revealed that films deposited on glass substrate (−0.173) were compressive, however, films deposited onto ITO (0.691) and on ZnO:Al (0.345) were tensile. Scanning electron microscopies (SEM) show that the morphologies of surface are porous in the form of nanopillars. The transmittance spectra indicated that the films of ZnO/ITO/glass and ZnO/ZnO:Al/glass exhibit a transmittance around 80% in the visible region. An empirical relationship modeled by theoretical numerical models has been presented for estimating refractive indices (n) relative to energy gap. All models indicate that the refractive index deceases with increasing energy band gap (Eg). 相似文献
99.
Patricia Amara Martin J. Field Cristobal Alhambra Jiali Gao 《Theoretical chemistry accounts》2000,104(5):336-343
Hybrid quantum mechanical (QM) and molecular mechanical (MM) potentials are becoming increasingly important for studying
condensed-phase systems but one of the outstanding problems in the field has been how to treat covalent bonds between atoms
of the QM and MM regions. Recently, we presented a generalized hybrid orbital (GHO) method that was designed to tackle this
problem for hybrid potentials using semiempirical QM methods [Gao et al. (1998) J Phys Chem A 102: 4714–4721]. We tested the method on some small molecules and showed that it performed well when compared to the purely
QM or MM potentials. In this article, we describe the formalism for the determination of the GHO energy derivatives and then
present the results of more tests aimed at validating the model. These tests, involving the calculation of the proton affinities
of some model compounds and a molecular dynamics simulation of a protein, indicate that the GHO method will prove useful for
the application of hybrid potentials to solution-phase macromolecular systems.
Received: 4 October 1999 / Accepted: 18 December 1999 / Published online: 5 June 2000 相似文献
100.