1,685 research outputs found
Diffusion couple studies of the Ni-Bi-Sn system
Investigations of Ni-Bi-Sn system were performed in order to inquire the phase diagram and to assess some diffusion kinetic parameters. For this purpose diffusion couples consisting of solid nickel (preliminary electroplated with tin) and liquid Bi-Sn phase were annealed at 370 °C. Three compositions (0.8, 0.6 and 0.4 mole fractions Sn) of the Bi-Sn melts were chosen. Annealing times from 24 to 216 h were applied. The phase and chemical compositions of the contact zone were determined by means of electron scanning microscope. It was confirmed that the diffusion layers consist mainly of Ni3Sn4 but other intermetallic phases grow as well. For the first time metastable Ni-Sn phases as NiSn and NiSn8 (NiSn9) were observed in metallurgical alloys (i.e. not in electroplated samples). The existence of a ternary compound previously reported in the literature was confirmed. More than one ternary Ni-Bi-Sn compounds might possibly be admitted. A growth coefficient of (2.29 ± 0.02) x 10-15 m2 s-1 was obtained. It was found that the apparent activation energy for diffusion layers growth (18 ± 8 kJ mol-1) is inferior to that one assessed at growth from solid state Bi-Sn mixtures (88 ± 12 kJ mol-1)
Mortality of patients with multiple sclerosis: a cohort study in UK primary care
We aimed to estimate rates, causes and risk factors of all-cause mortality in a large population-based cohort of multiple sclerosis (MS) patients compared with patients without MS. Using data from the UK General Practice Research Database, we identified MS cases diagnosed during 2001–2006 and validated using patients’ original records where possible. We also included MS cases during 1993–2000 identified and validated in an earlier study. Cases were matched to up to ten referents without MS by age, sex, index date (date of first MS diagnosis for cases and equivalent reference date for controls), general practice and length of medical history before first MS diagnosis. Patients were followed up to identify deaths; hazard ratios (HRs) and 95 % confidence intervals (CIs) were estimated using Cox-proportional regression. MS patients (N = 1,822) had a significantly increased risk of all-cause mortality compared with referents (N = 18,211); adjusted HR 1.7 (95 % CI 1.4–2.1). Compared with referents, female MS patients had a higher but not significantly different HR for death than males; adjusted HR 1.86 (95 % CI 1.46–2.38) vs. HR 1.31 (95 % CI 0.93–1.84), respectively. The most commonly recorded cause of death in MS patients was ‘MS’ (41 %), with a higher proportion recorded among younger patients. A significantly higher proportion of referents than MS patients had cancer recorded as cause of death (40 vs. 19 %). Patients with MS have a significant 1.7-fold increased risk of all-cause mortality compared with the general population. MS is the most commonly recorded cause of death among MS patients. Electronic supplementary material The online version of this article (doi:10.1007/s00415-014-7370-3) contains supplementary material, which is available to authorized users
Section on Prospects for Dark Matter Detection of the White Paper on the Status and Future of Ground-Based TeV Gamma-Ray Astronomy
This is a report on the findings of the dark matter science working group for
the white paper on the status and future of TeV gamma-ray astronomy. The white
paper was commissioned by the American Physical Society, and the full white
paper can be found on astro-ph (arXiv:0810.0444). This detailed section
discusses the prospects for dark matter detection with future gamma-ray
experiments, and the complementarity of gamma-ray measurements with other
indirect, direct or accelerator-based searches. We conclude that any
comprehensive search for dark matter should include gamma-ray observations,
both to identify the dark matter particle (through the charac- teristics of the
gamma-ray spectrum) and to measure the distribution of dark matter in galactic
halos.Comment: Report from the Dark Matter Science Working group of the APS
commissioned White paper on ground-based TeV gamma ray astronomy (19 pages, 9
figures
Effect of superficial treatment with new natural antioxidant on salmon (Salmo salar) lipid oxidation
Lipid oxidation is one of the main factors responsible for the quality loss in refrigerated and frozen stored fish products. The aim of the study was to evaluate the effect of superficial treatment of Atlantic salmon (Salmo salar) with dihydroquercetin (DHQ) solutions on the hydrolytic and oxidative changes in fish lipids during refrigerated storage. It was found that treatment with DHQ solution (1.0 g l−1) reduced approximately twice the free fatty acids content of chilled stored salmon. After 11 days of storage at 1 °С, the contents of hydroperoxides (HPO) and 2-thiobarbituric acid reactive substances (TBARS) of these samples decreased with 45.00 and 0.91 mg MDA/kg, respectively. The share of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) in control and experimental samples did not differ significantly (P>0.05). Results obtained show that the superficial treatment of salmon with DHQ solution (1.0 g l−1) delayed the hydrolytic and oxidative changes in fish lipids significantly, thus preserving the salmon freshness up to 11 days of storage at 1 °С
Squeezed between shells? On the origin of the Lupus I molecular cloud. - II. APEX CO and GASS HI observations
Accepted for publication in a future issue of Astronomy & Astrophysics. Reproduced with permission from Astronomy & Astrophysics. © 2018 ESO.Context. The Lupus I cloud is found between the Upper-Scorpius (USco) and the Upper-Centaurus-Lupus (UCL) sub-groups of the Scorpius-Centaurus OB-association, where the expanding USco H I shell appears to interact with a bubble currently driven by the winds of the remaining B-stars of UCL. Aims. We investigate if the Lupus I molecular could have formed in a colliding flow, and in particular, how the kinematics of the cloud might have been influenced by the larger scale gas dynamics. Methods. We performed APEX 13CO(2–1) and C 18O(2–1) line observations of three distinct parts of Lupus I that provide kinematic information on the cloud at high angular and spectral resolution. We compare those results to the atomic hydrogen data from the GASS H i survey and our dust emission results presented in the previous paper. Based on the velocity information, we present a geometric model for the interaction zone between the USco shell and the UCL wind bubble. Results. We present evidence that the molecular gas of Lupus I is tightly linked to the atomic material of the USco shell. The CO emission in Lupus I is found mainly at velocities between vLSR = 3–6 km s−1 which is in the same range as the H i velocities. Thus, the molecular cloud is co-moving with the expanding USco atomic H i shell. The gas in the cloud shows a complex kinematic structure with several line-of-sight components that overlay each other. The non-thermal velocity dispersion is in the transonic regime in all parts of the cloud and could be injected by external compression. Our observations and the derived geometric model agree with a scenario where Lupus I is located in the interaction zone between the USco shell and the UCL wind bubble. Conclusions. The kinematics observations are consistent with a scenario where the Lupus I cloud formed via shell instabilities. The particular location of Lupus I between USco and UCL suggests that counter-pressure from the UCL wind bubble and pre-existing density enhancements, perhaps left over from the gas stream that formed the stellar subgroups, may have played a role in its formation.Peer reviewedFinal Accepted Versio
Degeneracy: a link between evolvability, robustness and complexity in biological systems
A full accounting of biological robustness remains elusive; both in terms of the mechanisms by which robustness is achieved and the forces that have caused robustness to grow over evolutionary time. Although its importance to topics such as ecosystem services and resilience is well recognized, the broader relationship between robustness and evolution is only starting to be fully appreciated. A renewed interest in this relationship has been prompted by evidence that mutational robustness can play a positive role in the discovery of adaptive innovations (evolvability) and evidence of an intimate relationship between robustness and complexity in biology.
This paper offers a new perspective on the mechanics of evolution and the origins of complexity, robustness, and evolvability. Here we explore the hypothesis that degeneracy, a partial overlap in the functioning of multi-functional components, plays a central role in the evolution and robustness of complex forms. In support of this hypothesis, we present evidence that degeneracy is a fundamental source of robustness, it is intimately tied to multi-scaled complexity, and it establishes conditions that are necessary for system evolvability
Assessing plant diversity and composition in grasslands across spatial scales: the standardised EDGG sampling methodology
This paper presents the details of the EDGG sampling methodology and its underlying rationales. The methodology has been applied during EDGG Research Expeditions and EDGG Field Workshops since 2009, and has been subsequently adopted by various other researchers. The core of the sampling are the EDGG Biodiversity Plots, which are 100‐m2 squares comprising, in two opposite corners, nested‐plot series of 0.0001, 0.001, 0.01, 0.1, 1 and 10 m2 square plots, in which all terricolous vascular plants, bryophytes and lichens are recorded using the shoot presence method. In the 10‐m2 plots, species cover is also estimated as a percentage and various environmental and structural parameters are recorded. Usually the EDGG Biodiversity Plots are complemented by the sampling of additional 10 m2 normal plots with the same parameters as the 10‐m2 corners of the first, allowing coverage of a greater environmental diversity and the achievement of higher statistical power in the subsequent analyses for this important grain size. The EDGG sampling methodology has been refined over the years, while its core has turned out to generate high‐quality, standardised data in an effective manner, which facilitates a multitude of analyses. In this paper we provide the current versions of our guidelines, field forms and data entry spreadsheets, as open‐access Online Resources to facilitate the easy implementation of this methodology by other researchers. We also discuss potential future additions and modifications to the approach, among which the most promising are the use of stratified‐random methods to a priori localise the plots and ideas to sample invertebrate taxa on the same plots and grain sizes, such as grasshoppers (Orthoptera) and vegetation‐dwelling spiders (Araneae). As with any other method, the EDGG sampling methodology is not ideal for every single purpose, but with its continuous improvements and its flexibility, it is a good multi‐ purpose approach. A particularly advantageous element, lacking in most other sampling schemes, including classical phytosociogical sampling, is the multi‐scale and multi‐taxon approach, which provides data that allow for deeper understanding of the generalities and idiosyncrasies of biodiversity patterns and their underlying drivers across scales and taxa
Production of a potential liquid plant bio-stimulant by immobilized Piriformospora indica in repeated-batch fermentation process
Piriformospora indica, a mycorrhizal-like fungus able to establish associations with roots of a wide range of plants, supporting plant nutrition and increasing plant resistance and tolerance to stress, was shown to solubilise phosphate applied in the form of animal bone char (HABO) in fermentation systems. The process of P solubilisation was caused most likely by proton extrusion and medium pH lowering. The fungal mycelium was successfully immobilized/retained in a polyurethane foam carrier. Further employment of the immobilized mycelium in repeated-batch fermentation process resulted in at least 5 cycles of P solubilization. The concentration of soluble P increased during the experiment with 1.0 and 3.0 g HABO l−1 and at the end of the 5th batch cycle reached 40.8 and 120 mg l−1, respectively. The resulting final liquid product, without or with solubilized phosphate, was found to significantly increase plant growth and P plant uptake. It can be used as a biostimulant containing microbial plant growth-promoting substances and soluble P derived from renewable sources (HABO) thus supporting the development of sustainable agro-ecosystems.This work was supported by Project CTM2014-53186-R, Ministerio de Economia y Competitividad-ES/EC FEDER Fund and the sabbatical Grant PRX16/00277 to NV
The Contribution of Social Networks to the Health and Self-Management of Patients with Long-Term Conditions: A Longitudinal Study
Evidence for the effectiveness of patient education programmes in changing individual self-management behaviour is equivocal. More distal elements of personal social relationships and the availability of social capital at the community level may be key to the mobilisation of resources needed for long-term condition self-management to be effective.
Aim: To determine how the social networks of people with long-term conditions (diabetes and heart disease) are associated with health-related outcomes and changes in outcomes over time.
Methods: Patients with chronic heart disease (CHD) or diabetes (n = 300) randomly selected from the disease registers of 19 GP practices in the North West of England. Data on personal social networks collected using a postal questionnaire, alongside face-to-face interviewing. Follow-up at 12 months via postal questionnaire using a self-report grid for network members identified at baseline.
Analysis: Multiple regression analysis of relationships between health status, self-management and health economics outcomes, and characteristics of patients’ social networks.
Results: Findings indicated that: (1) social involvement with a wider variety of people and groups supports personal self-management and physical and mental well-being; (2) support work undertaken by personal networks expands in accordance with health needs helping people to cope with their condition; (3) network support substitutes for formal care and can produce substantial saving in traditional health service utilisation costs. Health service costs were significantly (p0.01) reduced for patients receiving greater levels of illness work through their networks.
Conclusions: Support for self-management which achieves desirable policy outcomes should be construed less as an individualised set of actions and behaviour and more as a social network phenomenon. This study shows the need for a greater focus on harnessing and sustaining the capacity of networks and the importance of social involvement with community groups and resources for producing a more desirable and cost-effective way of supporting long term illness management
The degradation of p53 and its major E3 ligase Mdm2 is differentially dependent on the proteasomal ubiquitin receptor S5a.
p53 and its major E3 ligase Mdm2 are both ubiquitinated and targeted to the proteasome for degradation. Despite the importance of this in regulating the p53 pathway, little is known about the mechanisms of proteasomal recognition of ubiquitinated p53 and Mdm2. In this study, we show that knockdown of the proteasomal ubiquitin receptor S5a/PSMD4/Rpn10 inhibits p53 protein degradation and results in the accumulation of ubiquitinated p53. Overexpression of a dominant-negative deletion of S5a lacking its ubiquitin-interacting motifs (UIM)s, but which can be incorporated into the proteasome, also causes the stabilization of p53. Furthermore, small-interferring RNA (siRNA) rescue experiments confirm that the UIMs of S5a are required for the maintenance of low p53 levels. These observations indicate that S5a participates in the recognition of ubiquitinated p53 by the proteasome. In contrast, targeting S5a has no effect on the rate of degradation of Mdm2, indicating that proteasomal recognition of Mdm2 can be mediated by an S5a-independent pathway. S5a knockdown results in an increase in the transcriptional activity of p53. The selective stabilization of p53 and not Mdm2 provides a mechanism for p53 activation. Depletion of S5a causes a p53-dependent decrease in cell proliferation, demonstrating that p53 can have a dominant role in the response to targeting S5a. This study provides evidence for alternative pathways of proteasomal recognition of p53 and Mdm2. Differences in recognition by the proteasome could provide a means to modulate the relative stability of p53 and Mdm2 in response to cellular signals. In addition, they could be exploited for p53-activating therapies. This work shows that the degradation of proteins by the proteasome can be selectively dependent on S5a in human cells, and that this selectivity can extend to an E3 ubiquitin ligase and its substrate
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