963 research outputs found
Cellular mechanisms of auditory processing in the inferior colliculus: An in vivo patch clamp study
In this thesis, different aspects of central auditory processing in the inferior colliculus (IC) of young-adult mice and rats are described. With the “in vivo patch-clamp” technique we investigated the contribution of membrane propertie
Identification of Critical Molecular Determinants of West Nile Virus PrM Protein: A Potential Site for Antiviral Targeting
Digitalitzat per Artypla
Conflicts in Knowledge Management: Vistiting the Hidden Partner
As knowledge gains a reputation for being a critical resource in the information-intensive economy, organizations have doubled their efforts in trying to extract value from knowledge management policies. One particular aspect of knowledge management, which has gone unnoticed in academic research, is the presence of conflicts in knowledge activities. By adopting a conflict perspective of knowledge activities, this study arrives at a two-dimensional framework that defines knowledge conflicts in terms of its type and nature. Central to this paper is the fundamental idea that conflicts form an integral part of knowledge management and depending on how they are managed; conflicts may be formidable partners or dangerous adversaries in the corporate quest for knowledge-derived competitiveness
Topographic Changes in SARS Coronavirus–infected Cells at Late Stages of Infection
Scanning electron and atomic force microscopy was used for the first time to view the maturation of SARS-CoV at the cell surface
Triple-Pomeron Matrix Model for Dispersive Corrections to Nucleon-Nucleus Total Cross Section
Dispersive corrections to the total cross section for high-energy scattering
from a heavy nucleus are calculated using a matrix model, based on the
triple-Pomeron behavior of diffractive scattering from a single nucleon, for
the cross section operator connecting different states of the projectile
nucleon . Energy-dependent effects due to the decrease in longitudinal momentum
transfers and the opening of more channels with increasing energy are included.
The three leading terms in an expansion in the number of inelastic transitions
are evaluated and compared to exact results for the model in the uniform
nuclear density approximation for the the scattering of nucleons from Pb^{208}
for laboratory momenta ranging from 50 to 200 GeV/c.Comment: 16 pages, 2 figures, RevTex
Functional Specialization of Cellulose Synthase Isoforms in a Moss Shows Parallels with Seed Plants
The secondary cell walls of tracheary elements and fibers are rich in cellulose microfibrils that are helically oriented and laterally aggregated. Support cells within the leaf midribs of mosses deposit cellulose-rich secondary cell walls, but their biosynthesis and microfibril organization have not been examined. Although the Cellulose Synthase (CESA) gene families of mosses and seed plants diversified independently, CESA knockout analysis in the moss Physcomitrella patens revealed parallels with Arabidopsis (Arabidopsis thaliana) in CESA functional specialization, with roles for both subfunctionalization and neofunctionalization. The similarities include regulatory uncoupling of the CESAs that synthesize primary and secondary cell walls, a requirement for two or more functionally distinct CESA isoforms for secondary cell wall synthesis, interchangeability of some primary and secondary CESAs, and some CESA redundancy. The cellulose-deficient midribs of ppcesa3/8 knockouts provided negative controls for the structural characterization of stereid secondary cell walls in wild type P. patens. Sum frequency generation spectra collected from midribs were consistent with cellulose microfibril aggregation, and polarization microscopy revealed helical microfibril orientation only in wild type leaves. Thus, stereid secondary walls are structurally distinct from primary cell walls, and they share structural characteristics with the secondary walls of tracheary elements and fibers. We propose a mechanism for the convergent evolution of secondary walls in which the deposition of aggregated and helically oriented microfibrils is coupled to rapid and highly localized cellulose synthesis enabled by regulatory uncoupling from primary wall synthesis
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