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91.
The term quorum sensing (QS) refers to the ability of bacteria to regulate gene expression according to the accumulation of
signalling molecules that are made by every cell in the population. The erwiniae group of bacteria are often phytopathogens
and the expression of a number of their important virulence determinants and secondary metabolites is under QS control. The
erwiniae utilise two types of QS signalling molecules: N-acyl homoserine lactones and AI-2-type signalling molecules. Here, we review the regulatory networks involving QS in the
soft rot erwiniae. 相似文献
92.
Stephen T. Barnard Alex Pothen Horst Simon 《Numerical Linear Algebra with Applications》1995,2(4):317-334
The problem of reordering a sparse symmetric matrix to reduce its envelope size is considered. A new spectral algorithm for computing an envelope-reducing reordering is obtained by associating a Laplacian matrix with the given matrix and then sorting the components of a specified eigenvector of the Laplacian. This Laplacian eigenvector solves a continuous relaxation of a discrete problem related to envelope minimization called the minimum 2-sum problem. The permutation vector computed by the spectral algorithm is a closest permutation vector to the specified Laplacian eigenvector. Numerical results show that the new reording algorithm usually computes smaller envelope sizes than those obtained from the current standards such as the Gibbs—Poole—Stockmeyer (GPS) algorithm or the reverse Cuthill—McKee (RCM) algorithm in SPARSPAK, in some cases reducing the envelope by more than a factor of two. 相似文献
93.
94.
We study the problem of treatment planning in radiotherapy. We use an energy-dependent Boltzmann-based particle transport model as a partial integro-differential constraint for a convex optimization problem. We solve the resulting optimal control problem using a minimum entropy moment closure. Numerical results for problems on patient data are presented. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
95.
Although boron has been known for many years to be a successful dopant in bulk diamond, efficient doping of nanocrystalline diamond with boron is still being developed. In general, the location, configuration, and bonding structure of boron in nanodiamond is still unknown, including the fundamental question of whether it is located within grains or grain boundaries of thin films and whether it is within the core or at the surface of nanoparticles. Presented here are density functional tight-binding simulations examining the configuration, potential energy surface, and electronic charge of substitutional boron in various types of nanocrystalline diamond. The results predict that boron is likely to be positioned at the surface of isolated particles and at the grain boundary of thin-film samples. 相似文献
96.
97.
V. ARÁMBULA-VILLAZANA M. SOLACHE-RÍOS M. T. OLGUÍN 《Journal of inclusion phenomena and macrocyclic chemistry》2006,55(3-4):237-245
Many factors may affect the heavy metals sorption on natural zeolites among them the temperature, for this reason in this paper the cadmium retention behavior on Mexican zeolitic rich tuff as a function of temperature is considered. The kinetic and the isotherms were determined at 303, 318, and 333 K, the remaining cadmium in the solution samples was analyzed by atomic absorption spectrometry. The pseudo-second order rate constant, k, as well as the apparent diffusion coefficients were calculated from the cadmium uptake by the zeolitic rock as a function of the contact time and temperature, the highest amounts were found for the experiments done at 333 K. The maximum cadmium adsorption capacity by the zeolitic material was 12.2 mg Cd2+/g at 318 K corresponding to 20% of the effective ion exchange capacity of the Chihuahua zeolitic rock. In order to explain the cadmium sorption behavior different kinetics and isotherm models were considered. 相似文献
98.
In this paper the relation betweenEP--matrices andE
k
P--matrices over an arbitrary filedF is studied. Further, conditions for the product ofE
k
P--matrices to be anE
k
P--matrix and for the reverse order law to hold for the polynomial Moore-Penrose inverse of the product ofE
k
P--matrices are determined 相似文献
99.
MK Hossain-Ibrahim K Rezajooi JK MacNally MRJ Mason AR Lieberman PN Anderson 《BMC neuroscience》2006,7(1):8-21
Background
Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS) was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker). Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation. 相似文献100.
C. F. Hickethier M. Marder V. Tolkmitt D. P. Barnard E. R. Barnard T. H. Rogers B. H. Shoemaker R. F. Wilkin F. H. Garner C. J. Kelly J. L. Taylor F. Eversund R. Schmidt Seufert W. O. Andrews W. F. Weiland E. Graefe R. E. Burk K. Schröder P. H. Conradson E. Andre J. Roche J. Zdarsky Joseph Müller E. Feigl F. Chierer B. Gordon C. J. Boner L. W. Yagle G. A. Williams S. T. Schicktanz M. R. Fenske C. O. Tongberg D. Quiggle D. S. Cryder C. Ehlers C. Stephan B. W. Thomas R. B. Dow W. R. Ham 《Analytical and bioanalytical chemistry》1940,120(9-10):358-368