DRASTIC—INSIGHTS:querying information in a plant gene expression database

DRASTIC––Database Resource for the Analysis of Signal Transduction In Cells (http://www.drastic.org.uk/) has been created as a first step towards a data-based approach for constructing signal transduction pathways. DRASTIC is a relational database of plant expressed sequence tags and genes up- or down-regulated in response to various pathogens, chemical exposure or other treatments such as drought, salt and low temperature. More than 17700 records have been obtained from 306 treatments affecting 73 plant species from 512 peer-reviewed publications with most emphasis being placed on data from Arabidopsis thaliana. DRASTIC has been developed by the Scottish Crop Research Institute and the Abertay University and allows rapid identification of plant genes that are up- or down-regulated by multiple treatments and those that are regulated by a very limited (or perhaps a single) treatment. The INSIGHTS (INference of cell SIGnaling HypoTheseS) suite of web-based tools allows intelligent data mining and extraction of information from the DRASTIC database. Potential response pathways can be visualized and comparisons made between gene expression patterns in response to various treatments. The knowledge gained informs plant signalling pathways and systems biology investigations

P2 receptors in macrophage fusion and osteoclast formation

Cells of the mononuclear phagocyte lineage fuse to form multinucleated giant cells and osteoclasts. Several lines of evidence suggest that P2 receptors, in particular P2X7, are involved in this process, although P2X7 is not absolutely required for fusion because P2X7-null mice form multinucleated osteoclasts. Extracellular ATP may be an important regulator of macrophage fusion

Mobile, wearable and ingestible health technologies : towards a critical research agenda

In this article, we review critical research on mobile and wearable health technologies focused on the promotion of ‘healthy lifestyles’. We begin by discussing key governmental and policy interests which indicate a shift towards greater digital integration in health care. Subsequently, we review relevant research literature, which highlights concerns about inclusion, social justice, and ownership of mobile health data, which we argue, provoke a series of key sociological questions that are in need of additional investigation. We examine the expansion of what counts as health data, as a basis for advocating the need for greater research into this area. Finally, we consider how digital devices raise questions about the reconfiguration of relationships, behaviours, and concepts of individuality

Many Body Theory of Charge Transfer in Hyperthermal Atomic Scattering

We use the Newns-Anderson Hamiltonian to describe many-body electronic processes that occur when hyperthermal alkali atoms scatter off metallic surfaces. Following Brako and Newns, we expand the electronic many-body wavefunction in the number of particle-hole pairs (we keep terms up to and including a single particle-hole pair). We extend their earlier work by including level crossings, excited neutrals and negative ions. The full set of equations of motion are integrated numerically, without further approximations, to obtain the many-body amplitudes as a function of time. The velocity and work-function dependence of final state quantities such as the distribution of ion charges and excited atomic occupancies are compared with experiment. In particular, experiments that scatter alkali ions off clean Cu(001) surfaces in the energy range 5 to 1600 eV constrain the theory quantitatively. The neutralization probability of Na$^+$ ions shows a minimum at intermediate velocity in agreement with the theory. This behavior contrasts with that of K$^+$, which shows ... (7 figures, not included. Figure requests: [email protected])Comment: 43 pages, plain TeX, BUP-JBM-

Polymorphisms in the P2X7 receptor gene are associated with low lumbar spine bone mineral density and accelerated bone loss in post-menopausal women

The P2X7 receptor gene (P2RX7) is highly polymorphic with five previously described loss-of-function (LOF) single-nucleotide polymorphisms (SNP; c.151+1G>T, c.946G>A, c.1096C>G, c.1513A>C and c.1729T>A) and one gain-of-function SNP (c.489C>T). The purpose of this study was to determine whether the functional P2RX7 SNPs are associated with lumbar spine (LS) bone mineral density (BMD), a key determinant of vertebral fracture risk, in post-menopausal women. We genotyped 506 post-menopausal women from the Aberdeen Prospective Osteoporosis Screening Study (APOSS) for the above SNPs. Lumbar spine BMD was measured at baseline and at 6–7 year follow-up. P2RX7 genotyping was performed by homogeneous mass extension. We found association of c.946A (p.Arg307Gln) with lower LS-BMD at baseline (P=0.004, β=−0.12) and follow-up (P=0.002, β=−0.13). Further analysis showed that a combined group of subjects who had LOF SNPs (n=48) had nearly ninefold greater annualised percent change in LS-BMD than subjects who were wild type at the six SNP positions (n=84; rate of loss=−0.94%/year and −0.11%/year, respectively, P=0.0005, unpaired t-test). This is the first report that describes association of the c.946A (p.Arg307Gln) LOF SNP with low LS-BMD, and that other LOF SNPs, which result in reduced or no function of the P2X7 receptor, may contribute to accelerated bone loss. Certain polymorphic variants of P2RX7 may identify women at greater risk of developing osteoporosis

Self-diffusion of adatoms, dimers, and vacancies on Cu(100)

We use ab initio static relaxation methods and semi-empirical molecular-dynamics simulations to investigate the energetics and dynamics of the diffusion of adatoms, dimers, and vacancies on Cu(100). It is found that the dynamical energy barriers for diffusion are well approximated by the static, 0 K barriers and that prefactors do not depend sensitively on the species undergoing diffusion. The ab initio barriers are observed to be significantly lower when calculated within the generalized-gradient approximation (GGA) rather than in the local-density approximation (LDA). Our calculations predict that surface diffusion should proceed primarily via the diffusion of vacancies. Adatoms are found to migrate most easily via a jump mechanism. This is the case, also, of dimers, even though the corresponding barrier is slightly larger than it is for adatoms. We observe, further, that dimers diffuse more readily than they can dissociate. Our results are discussed in the context of recent submonolayer growth experiments of Cu(100).Comment: Submitted to the Physical Review B; 15 pages including postscript figures; see also http://www.centrcn.umontreal.ca/~lewi

Theoretical analysis of the electronic structure of the stable and metastable c(2x2) phases of Na on Al(001): Comparison with angle-resolved ultra-violet photoemission spectra

Using Kohn-Sham wave functions and their energy levels obtained by density-functional-theory total-energy calculations, the electronic structure of the two c(2x2) phases of Na on Al(001) are analysed; namely, the metastable hollow-site structure formed when adsorption takes place at low temperature, and the stable substitutional structure appearing when the substrate is heated thereafter above ca. 180K or when adsorption takes place at room temperature from the beginning. The experimentally obtained two-dimensional band structures of the surface states or resonances are well reproduced by the calculations. With the help of charge density maps it is found that in both phases, two pronounced bands appear as the result of a characteristic coupling between the valence-state band of a free c(2x2)-Na monolayer and the surface-state/resonance band of the Al surfaces; that is, the clean (001) surface for the metastable phase and the unstable, reconstructed "vacancy" structure for the stable phase. The higher-lying band, being Na-derived, remains metallic for the unstable phase, whereas it lies completely above the Fermi level for the stable phase, leading to the formation of a surface-state/resonance band-structure resembling the bulk band-structure of an ionic crystal.Comment: 11 pages, 11 postscript figures, published in Phys. Rev. B 57, 15251 (1998). Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm