Using permeable membranes to produce hydrogen and oxygen from water

Concept may make it profitable to obtain hydrogen fuel from water. Laboratory tests have demonstrated that method enables decomposition of water several orders of magnitude beyond equilibrium state where only small amounts of free hydrogen are present

From Scientific Discovery to Cures: Bright Stars within a Galaxy

We propose that data mining and network analysis utilizing public databases can identify and quantify relationships between scientific discoveries and major advances in medicine (cures). Further development of such approaches could help to increase public understanding and governmental support for life science research and could enhance decision making in the quest for cures

Isotopic (δ18O and δ2H) Integrity of Water Samples Collected and Stored by Automatic Samplers

Stable water isotopes are increasingly becoming part of routine monitoring programs that use automatic samplers. The objectives of this study were to quantify the uncertainty in isotope signatures due to the length of sample storage (1–24 d) inside autosamplers over a range of air temperatures (5–35°C) and to evaluate the effectiveness of two evaporation reduction measures (mineral oil and high density polyethylene balls). Results of the laboratory study showed that up to 11.8% of the sample volume evaporated when samples were stored in an autosampler at 35°C for 24 d. To prevent significant water isotope fractionation, samples should be retrieved from autosampler

Simulation, modelling and development of the metris RCA

In partnership with Metris UK we discuss the utilisation of modelling and simulation methods in the development of a revolutionary 7-axis Robot CMM Arm (RCA). An offline virtual model is described, facilitating pre-emptive collision avoidance and assessment of optimal placement of the RCA relative to scan specimens. Workspace accessibility of the RCA is examined under a range of geometrical assumptions and we discuss the effects of arbitrary offsets resulting from manufacturing tolerances. Degeneracy is identified in the number of ways a given pose may be attained and it is demonstrated how a simplified model may be exploited to solve the inverse kinematics problem of finding the “correct” set of joint angles. We demonstrate how the seventh axis may be utilised to avoid obstacles or otherwise awkward poses, giving the unit greater dexterity than traditional CMMs. The results of finite element analysis and static force modelling on the RCA are presented which provide an estimate of the forces exerted on the internal measurement arm in a range of poses

Characteristics, accuracy and reverification of robotised articulated arm CMMs

VDI article 2617 specifies characteristics to describe the accuracy of articulated arm coordinate measuring machines (AACMMs) and outlines procedures for checking them. However the VDI prescription was written with a former generation of machines in mind: manual arms exploiting traditional touch probe technologies. Recent advances in metrology have given rise to noncontact laser scanning tools and robotic automation of articulated arms – technologies which are not adequately characterised using the VDI specification. In this paper we examine the “guidelines” presented in VDI 2617, finding many of them to be ambiguous and open to interpretation, with some tests appearing even to be optional. The engineer is left significant flexibility in the execution of the test procedures and the manufacturer is free to specify many of the test parameters. Such flexibility renders the VDI tests of limited value and the results can be misleading. We illustrate, with examples using the Nikon RCA, how a liberal interpretation of the VDI guidelines can significantly improve accuracy characterisation and suggest ways in which to mitigate this problem. We propose a series of stringent tests and revised definitions, in the same vein as VDI 2617 and similar US standards, to clarify the accuracy characterisation process. The revised methodology includes modified acceptance and reverification tests which aim to accommodate emerging technologies, laser scanning devices in particular, while maintaining the spirit of the existing and established standards. We seek to supply robust re-definitions for the accepted terms “zero point” and “useful arm length”, pre-supposing nothing about the geometry of the measuring device. We also identify a source of error unique to robotised AACMMs employing laser scanners – the forward-reverse pass error. We show how eliminating this error significantly improves the repeatability of a device and propose a novel approach to the testing of probing error based on statistical uncertainty

Highly Coordinated Gene Regulation in Mouse Skeletal Muscle Regeneration

Mammalian skeletal muscles are capable of regeneration after injury. Quiescent satellite cells are activated to reenter the cell cycle and to differentiate for repair, recapitulating features of myogenesis during embryonic development. To understand better the molecular mechanism involved in this process in vivo, we employed high density cDNA microarrays for gene expression profiling in mouse tibialis anterior muscles after a cardiotoxin injection. Among 16,267 gene elements surveyed, 3,532 elements showed at least a 2.5-fold change at one or more time points during a 14-day time course. Hierarchical cluster analysis and semiquantitative reverse transcription-PCR showed induction of genes important for cell cycle control and DNA replication during the early phase of muscle regeneration. Subsequently, genes for myogenic regulatory factors, a group of imprinted genes and genes with functions to inhibit cell cycle progression and promote myogenic differentiation, were induced when myogenic stem cells started to differentiate. Induction of a majority of these genes, including E2f1 and E2f2, was abolished in muscles lacking satellite cell activity after gamma radiation. Regeneration was severely compromised in E2f1 null mice but not affected in E2f2 null mice. This study identifies novel genes potentially important for muscle regeneration and reveals highly coordinated myogenic cell proliferation and differentiation programs in adult skeletal muscle regeneration in vivo

Systematic review of disease-modifying antirheumatic drugs for juvenile idiopathic arthritis

<p>Abstract</p> <p>Background</p> <p>Treatment of juvenile idiopathic arthritis (JIA) with disease-modifying antirheumatic drugs (DMARDs) may improve outcomes compared to conventional therapy (e.g., non-steroidal anti-inflammatory drugs, intra-articular corticosteroids). The purpose of this systematic review was to evaluate the comparative effectiveness and safety of DMARDs versus conventional therapy and versus other DMARDs.</p> <p>Results</p> <p>A systematic evidence review of 156 reports identified in MEDLINE^®, EMBASE^®, and by hand searches. There is some evidence that methotrexate is superior to conventional therapy. Among children who have responded to a biologic DMARD, randomized discontinuation trials suggest that continued treatment decreases the risk of having a flare. However, these studies evaluated DMARDs with different mechanisms of action (abatacept, adalimumab, anakinra, etanercept, intravenous immunoglobulin, tocilizumab) and used varying comparators and follow-up periods. Rates of serious adverse events are similar between DMARDs and placebo in published trials. This review identified 11 incident cases of cancer among several thousand children treated with one or more DMARD.</p> <p>Conclusions</p> <p>Few data are available to evaluate the comparative effectiveness of either specific DMARDs or general classes of DMARDs. However, based on the overall number, quality, and consistency of studies, there is moderate strength of evidence to support that DMARDs improve JIA-associated symptoms. Limited data suggest that short-term risk of cancer is low.</p

The energy source of the filaments around the giant galaxy NGC1275

The brightest galaxy in the nearby Perseus cluster, NGC1275, is surrounded by a network of filaments. These were first observed through their Halpha emission but are now known to have a large molecular component with a total mass approaching 10^11Msun of gas. The filaments are embedded in hot intracluster gas and stretch over 80 kpc. They have an unusual low excitation spectrum which is well modelled by collisional heating and ionization by secondary electrons. Here we note that the surface radiative flux from the outer filaments is close to the energy flux impacting on them from particles in the hot gas. We propose that the secondary electrons within the cold filaments, which excite the observed submillimetre through UV emission, are due to the hot surrounding gas efficiently penetrating the cold gas through reconnection diffusion. Some of the soft X-ray emission seen from the filaments is then due to charge exchange, although this is insufficient to account for all the observed X-ray flux. The filaments are complex with multiphase gas. Interpenetration of hot and cold gas leads to the filaments growing in mass, at a rate of up to 100Msunpyr. The lack of soft X-ray cooling emission in cool core clusters is then due to the non-radiative cooling of hot gas on mixing with cold gas around and within the central galaxy.Comment: 7 pages, 4 figures, MNRAS in pres

Tuning the Charge Density Wave and Superconductivity in CuxTaS2

We report the characterization of layered, 2H-type CuxTaS2, for x between 0 and 0.12. The charge density wave (CDW), at 70 K for TaS2, is destabilized with Cu doping. The sub-1K superconducting transition in undoped 2H-TaS2 jumps quickly to 2.5 K at low x, increases to 4.5 K at the optimal composition Cu0.04TaS2, and then decreases at higher x. The electronic contribution to the specific heat, first increasing and then decreasing as a function of Cu content, is 12 mJ mol-1 K-2 at Cu0.04TaS2. Electron diffraction studies show that the CDW remains present at the optimal superconducting composition, but with both a changed q vector and decreased coherence length. We present an electronic phase diagram for the system.Comment: 7 pages, 9 figures. To be published in Physical Review

Star formation towards the Scutum tangent region and the effects of Galactic environment

By positional matching to the catalogue of Galactic Ring Survey molecular clouds, we have derived distances to 793 Bolocam Galactic Plane Survey (BGPS) sources out of a possible 806 located within the region defined by Galactic longitudes l = 28.5 degr to 31.5 degr and latitudes |b| < 1 degr. This section of the Galactic Plane contains several major features of Galactic structure at different distances, mainly mid-arm sections of the Perseus and Sagittarius spiral arms and the tangent of the Scutum-Centarus arm, which is coincident with the end of the Galactic Long Bar. By utilising the catalogued cloud distances plus new kinematic distance determinations, we are able to separate the dense BGPS clumps into these three main line-of-sight components to look for variations in star-formation properties that might be related to the different Galactic environments. We find no evidence of any difference in either the clump mass function or the average clump formation efficiency (CFE) between these components that might be attributed to environmental effects on scales comparable to Galactic-structure features. Despite having a very high star-formation rate, and containing at least one cloud with a very high CFE, the star formation associated with the Scutum-Centarus tangent does not appear to be in any way abnormal or different to that in the other two spiral-arm sections. Large variations in the CFE are found on the scale of individual clouds, however, which may be due to local triggering agents as opposed to the large-scale Galactic structure.Comment: 11 pages, 8 figures. Accepted for publication in the Monthly Notices of the Royal Astronomical Societ