14,067 research outputs found
Two new methods to increase the contrast of track-etch neutron radiographs
In one method, fluorescent dye is deposited into tracks of radiograph and viewed under ultraviolet light. In second method, track-etch radiograph is placed between crossed polaroid filters, exposed to diffused light and resulting image is projected onto photographic film
Specific isoforms of translation initiation factor 4GI show differences in translational activity
The eukaryotic initiation factor (eIF) 4GI gene locus (eIF4GI) contains three identified promoters, generating alternately spliced mRNAs, yielding a total of five eIF4GI protein isoforms. Although eIF4GI plays a critical role in mRNA recruitment to the ribosomes, little is known about the functions of the different isoforms, their partner binding capacities, or the role of the homolog, eIF4GII, in translation initiation. To directly address this, we have used short interfering RNAs (siRNAs) expressed from DNA vectors to silence the expression of eIF4GI in HeLa cells. Here we show that reduced levels of specific mRNA and eIF4GI isoforms in HeLa cells promoted aberrant morphology and a partial inhibition of translation. The latter reflected dephosphorylation of 4E-BP1 and decreased eIF4F complex levels, with no change in eIF2 alpha phosphorylation. Expression of siRNA-resistant Myc-tagged eIF4GI isoforms has allowed us to show that the different isoforms exhibit significant differences in their ability to restore translation rates. Here we quantify the efficiency of eIF4GI promoter usage in mammalian cells and demonstrate that even though the longest isoform of eIF4GI (eIF4GIf) was relatively poorly expressed when reintroduced, it was more efficient at promoting the translation of cellular mRNAs than the more highly expressed shorter isoforms used in previous functional studies
Surface networks
© Copyright CASA, UCL. The desire to understand and exploit the structure of continuous surfaces is common to researchers in a range of disciplines. Few examples of the varied surfaces forming an integral part of modern subjects include terrain, population density, surface atmospheric pressure, physico-chemical surfaces, computer graphics, and metrological surfaces. The focus of the work here is a group of data structures called Surface Networks, which abstract 2-dimensional surfaces by storing only the most important (also called fundamental, critical or surface-specific) points and lines in the surfaces. Surface networks are intelligent and “natural ” data structures because they store a surface as a framework of “surface ” elements unlike the DEM or TIN data structures. This report presents an overview of the previous works and the ideas being developed by the authors of this report. The research on surface networks has fou
Substrate Induced Denitrification over or under Estimates Shifts in Soil N2/N2O Ratios
Funding: Funding was provided by the Biotechnology and Biological Sciences Research Council, BBSRC UK (http://www.bbsrc.ac.uk). Grant number BB/H013431/1. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
The chain rule for -differentiation
Let be a perfect, compact subset of the complex plane, and let
denote the (complex) algebra of continuously
complex-differentiable functions on . Then is a normed algebra
of functions but, in some cases, fails to be a Banach function algebra. Bland
and the second author investigated the completion of the algebra ,
for certain sets and collections of paths in , by
considering -differentiable functions on .
In this paper, we investigate composition, the chain rule, and the quotient
rule for this notion of differentiability. We give an example where the chain
rule fails, and give a number of sufficient conditions for the chain rule to
hold. Where the chain rule holds, we observe that the Fa\'a di Bruno formula
for higher derivatives is valid, and this allows us to give some results on
homomorphisms between certain algebras of -differentiable
functions.Comment: 12 pages, submitte
Abstract Swiss Cheese Space and the Classicalisation of Swiss Cheeses
Swiss cheese sets are compact subsets of the complex plane obtained by
deleting a sequence of open disks from a closed disk. Such sets have provided
numerous counterexamples in the theory of uniform algebras. In this paper, we
introduce a topological space whose elements are what we call "abstract Swiss
cheeses". Working within this topological space, we show how to prove the
existence of "classical" Swiss cheese sets (as discussed in a paper of
Feinstein and Heath from 2010) with various desired properties.
We first give a new proof of the Feinstein-Heath classicalisation theorem. We
then consider when it is possible to "classicalise" a Swiss cheese while
leaving disks which lie outside a given region unchanged. We also consider sets
obtained by deleting a sequence of open disks from a closed annulus, and we
obtain an analogue of the Feinstein-Heath theorem for these sets. We then
discuss regularity for certain uniform algebras. We conclude with an
application of these techniques to obtain a classical Swiss cheese set which
has the same properties as a non-classical example of O'Farrell (1979).Comment: To appear in the Journal of Mathematical Analysis and Application
Commentary: Nicotinic acetylcholine receptor α9 and α10 subunits are expressed in the brain of mice
Fil: Morley, Barbara J.. Boys Town National Research Hospita; Estados UnidosFil: Whiteaker, Paul. Barrow Neurological Institute; Estados UnidosFil: Elgoyhen, Ana Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentin
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