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排序方式: 共有1447条查询结果,搜索用时 281 毫秒
981.
Linda P. Jakobsen Rehannah Borup Janni Vestergaard Lars A. Larsen Kasper Lage Lisa Leth Maroun Inger Kjaer Carsten U. Niemann Mikael Andersen Mary A. Knudsen Kjeld M?llg?rd Niels Tommerup 《Experimental & molecular medicine》2009,41(2):77-85
Cleft lip and/or palate (CL/P) is a common congenital malformation with a complex etiology which is not fully elucidated yet. Epidemiological studies point to different etiologies in the cleft lip and palate subgroups, isolated cleft lip (CL), isolated cleft palate (CP) and combined cleft lip and palate (CLP). In order to understand the biological basis in these cleft lip and palate subgroups better we studied the expression profiles in human tissue from patients with CL/P. In each of the CL/P subgroups, samples were obtained from three patients and gene expression analysis was performed. Moreover, selected differentially expressed genes were analyzed by quantitative RT-PCR, and by immunohistochemical staining of craniofacial tissue from human embryos. Osteopontin (SPP1) and other immune related genes were significantly higher expressed in palate tissue from patients with CLP compared to CP and immunostaining in palatal shelves against SPP1, chemokine receptor 4 (CXCR4) and serglycin (PRG1) in human embryonic craniofacial tissue were positive, supporting a role for these genes in palatal development. However, gene expression profiles are subject to variations during growth and therefore we recommend that future gene expression in CL/P studies should use tissue from the correct embryonic time and place if possible, to overcome the biases in the presented study. 相似文献
982.
M. Yu. Zaslavsky D. Yu. Maksimov A. Kh. Pergament 《Computational Mathematics and Mathematical Physics》2006,46(10):1753-1767
Algorithms for solving the two-dimensional combustion problem for premixed flames are proposed and examined. The solution method is based on splitting into convective and diffusion parts according to the processes involved. A high-resolution explicit quasi-monotone scheme with flux correction is used for the hyperbolic part. For the parabolic part, the scheme is conservative and the source in the heat equation is set to be positive; i.e., the scheme ensures that the different thermodynamic consequences of the original equations hold; therefore, the scheme is thermodynamically conditioned. The applicability of the scheme to the full and purely gasdynamic problems is examined under various types of initial conditions and with various flux limiters. Numerical results are presented for one-and two-dimensional problems, including the Frank-Kamenetskii classical problem in two dimensions. The flame is shown to become turbulent in sufficiently wide pipes. 相似文献
983.
Zhang Hua Sheng Wancheng 《高校应用数学学报(英文版)》2006,21(1):30-40
§1IntroductionIn the present paper,we are interested in solving the Cauchy problem for linearizedsystem of two-dimensional isentropic flow with initial data in gas dynamicsρt+ρ0xu+yv=0,ut+p′(ρρ00)xρ=0,vt+p′(ρ0ρ0)yρ=0,(1.1)t=0:(ρ,u,v)=(ρ0(r),u0(r),v0(r)),(1.2)whereρis the density,(u,v)is the velocity,ρ0is a positive constant,p=p(ρ)is theequation of state satisfying p′(ρ0)>0,(r,θ)is the polar coordinate such thatx=rcosθ,y=rsinθ,0≤r<+∞,0≤θ≤2π… 相似文献
984.
Conservation laws, hierarchy of dynamics and explicit integration of nonholonomic systems 总被引:1,自引:1,他引:0
This paper can be regarded as a continuation of our previous work [1, 2] on the hierarchy of the dynamical behavior of nonholonomic
systems. We consider different mechanical systems with nonholonomic constraints; in particular, we examine the existence of
tensor invariants (laws of conservation) and their connection with the behavior of a system. Considerable attention is given
to the possibility of conformally Hamiltonian representation of the equations of motion, which is mainly used for the integration
of the considered systems.
相似文献
985.
L. M. Skvortsov 《Computational Mathematics and Mathematical Physics》2007,47(6):915-923
An explicit multistep method of variable order for integrating stiff systems with high accuracy and low computational costs is examined. To stabilize the computational scheme, componentwise estimates are used for the eigenvalues of the Jacobian matrix having the greatest moduli. These estimates are obtained at preliminary stages of the integration step. Examples are given to demonstrate that, for certain stiff problems, the method proposed is as efficient as the best implicit methods. 相似文献
986.
The class of microarray games and the relevance index for genes 总被引:2,自引:1,他引:1
Nowadays, microarray technology is available to generate a huge amount of information on gene expression. This information
must be statistically processed and analyzed, in particular, to identify those genes which are useful for the diagnosis and
prognosis of specific diseases. We discuss the possibility of applying game-theoretical tools, like the Shapley value, to
the analysis of gene expression data.
Via a “truncation” technique, we build a coalitional game whose aim is to stress the relevance (“sufficiency”) of groups of
genes for the specific disease we are interested in. The Shapley value of this game is used to select those genes which deserve
further investigation. To justify the use of the Shapley value in this context, we axiomatically characterize it using properties
with a genetic interpretation.
The authors are grateful to two anonymous referees for their extremely helpful comments.
An earlier version of this paper was presented at the VI Spanish Meeting on Game Theory and Practice, July 12–14, 2004, Elche,
Spain.
S. Moretti gratefully acknowledges the financial support of the EU project NewGeneris, European Union 6th FP (FOOD-CT-2005-016320). 相似文献
987.
热传导方程的小波解法 总被引:12,自引:0,他引:12
本文利用微分算子的小波表示,讨论一维热传导方程初值问题的Daubechies小波解,给出此问题的显式离散格式。由于小波在时间和频率上的局部性,此方法特别适用于有奇异解的热传导方程,逼近精度高,而且没有发生解的振荡现象。 相似文献
988.
989.
A PCR-based homologous cloning strategy was used to identify an actin gene from the roots of Chinese licorice(Glycyrrhiza uralensis Fisch). Results of sequence analysis indicate that a 1137 bp cDNA with an open reading frame encoding 377 amino acids,actin ortholog,GuActin,was successfully cloned and characterized(GenBank accession No. EU190972). Thus far,GuActin is the first actin of Chinese licorice that has been identified at a molecular level. Analysis by Northern blot shows that GuActin was expressed st... 相似文献
990.
We study a one-equation RANS model with eddy viscosities that include, as a special case, the classical Kolmogorov–Prandtl
expression. Under mild assumptions on the data, we prove the existence of a weak solution involving a defect measure. For
external forces with sufficiently small norm, we obtain the existence of a weak solution in the usual sense.
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