6,139 research outputs found
Collaborate to innovate
Innovation is something that many governments strive to support, in both the
private and public sectors. By bridging the two sectors and creating novel
partnerships, public sector expenditure can be reduced
Mammalian cells in culture actively export specific microRNAs
The discovery of microRNAs (miRNAs) as a new class of regulators of gene expression has triggered an explosion of research, but has left many unanswered questions about how this regulation works and how it is integrated with other regulatory mechanisms. A number of miRNAs have been found to be present in blood plasma and other body fluids of humans and mice in surprisingly high concentrations. This observation was unexpected in two respects: first, the fact that these molecules are present at all outside the cell at significant concentrations; and second, that these molecules appear to be stable outside of the cell. In light of this it has been suggested that the biological function of miRNAs may also extend outside of the cell and mediate cell-cell communication^[1-5]^. Such a system would be expected to export specific miRNAs from cells in response to specific biological stimuli. We report here that after serum deprivation several human cell lines tested do export a spectrum of miRNAs into the culture medium. The export response is substantial and prompt. The exported miRNAs are found both within and outside of microvesicles and exosomes. We have identified some candidate protein components of this system outside the cell, and found one exported protein that plays a role in protecting miRNA from degradation. Our results point to a hitherto unrecognized and uncharacterized miRNA trafficking system in mammalian cells that may involve cell-cell communication
Entropy of Folding of the Triangular Lattice
The problem of counting the different ways of folding the planar triangular
lattice is shown to be equivalent to that of counting the possible 3-colorings
of its bonds, a dual version of the 3-coloring problem of the hexagonal lattice
solved by Baxter. The folding entropy Log q per triangle is thus given by
Baxter's formula q=sqrt(3)(Gamma[1/3])^(3/2)/2pi =1.2087...Comment: 9 pages, harvmac, epsf, uuencoded, 5 figures included, Saclay
preprint T/9401
The existence of matrices with prescribed characteristic and permanental polynomials
AbstractLet d(λ) and p(λ) be monic polynomials of degree n⩾2 with coefficients in F, an algebraically closed field or the field of all real numbers. Necessary and sufficient conditions for the existence of an n-square matrix A over F such that det(λI−A)=d(λ) and per(λI−A=p(λ) are given in terms of the coefficients of d(λ) and p(λ)
Innovation in the design of continuous flight auger and bored displacement piles
The field of pile design and construction in the United Kingdom is currently in a period of
change. Not only are new processes and techniques being developed but also the legislative
landscape is changing with the introduction of new Europe wide normative standards (BSI,
2004, 2007).
This project sought to optimise pile design through better understanding and interpretation of
ground conditions and of the pile-soil interaction for two pile types, continuous flight auger
and bored displacement piles.
Quantitative methods for interpreting and summarising previous knowledge and experience
have been developed; the strata are divided into discrete bands and properties are represented
with summary statistics. Experience and previous knowledge relating to the shear strength of
London Clay have been quantified and presented using this approach. Furthermore, a
straightforward tool has been provided for the implementation of such data into design; the
previous knowledge and new site specific data are combined using Bayesian updating.
Through use of this technique, the uncertainty associated with interpreting ground conditions
from site data has been demonstrated to be reduced. The techniques described have been
adopted into design practice within the sponsoring company.
Bored displacement piles are a relatively new pile type. There is little published data or
scientific understanding of the processes undergone by the soils during and after construction
and the effect that these have on pile performance. This research identified the need for, and
developed, a unified framework of descriptors for the various types of bored displacement
pile and investigated the installation energy and performance of bored displacement piles in
London Clay. The energy to construct the pile was observed to be highly variable and not
directly related to capacity. Performance of bored displacement piles was observed to be
similar to continuous flight auger piles of similar dimensions; typical values for the adhesion
between bored displacement piles and the surrounding soil were established and these were
comparable to those achieved by continuous flight auger piles.In addition, to enable the analysis of the probability of failure of a pile, the sources of
variation have been investigated and the variability quantified. Besides the soil conditions, the
dimensions of the pile, notably pile diameter, were found to be a significant source of
variation
Development of a process-based data driven engineering design knowledge re-use system
This paper will describe the development of the web enabled version of a process based engineering design knowledge reuse system. The rationale for using the design process as a central element of knowledge management will be discussed. The system structure will be described. Evaluation of the prototype showed the most valuable attributes of system. Mapping the design process helped to create the product data model. Workshops were used to validate the system. A small number of product parameters are required for developing the product concept in the early stages. The research showed the importance of multi view validation and iteration in system development. It also showed the importance of graphics in design support. Key issues include: the importance of process capture, data model validation, the use of graphics in the interface, system design and system assessment
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