4,199 research outputs found
Rotational Broadening and Doppler Tomography of the Quiescent X-Ray Nova Centaurus X-4
We present high and intermediate resolution spectroscopy of the X-ray nova
Centaurus X-4 during its quiescent phase. Our analysis of the absorption
features supports a K3-K5V spectral classification for the companion star,
which contributes approximately 75 % of the total flux at Halpha. Using the
high resolution spectra we have measured the secondary star's rotational
broadening to be V_rot*sin(i) = 43 +/- 6 km/s and determined a binary mass
ratio of q=0.17 +/- 0.06. Combining our results for K_2 and q with the
published limits for the binary inclination, we constrain the mass of the
compact object and the secondary star to the ranges 0.49 < M_1 < 2.49 Msun and
0.04 < M_2 < 0.58 Msun. A Doppler image of the Halpha line shows emission
coming from the secondary star, but no hotspot is present. We discuss the
possible origins of this emission.Comment: 10 pages, 4 figures, accepted by MNRA
Effects of a multi-strain probiotic supplement for 12 weeks in circulating endotoxin levels and cardiometabolic profiles of medication naĂŻve T2DM patients: a randomized clinical trial
Background: The present randomized clinical trial characterized the beneficial effects of a multi-strain probiotics supplementation on improving circulating endotoxin levels (primary endpoint) and other cardiometabolic biomarkers (secondary endpoint) in patients with T2DM.
Methods: A total of 78 adult Saudi T2DM patients (naĂŻve and without co-morbidities) participated in this clinical trial and were randomized to receive twice daily placebo or probiotics [(2.5 Ă 109 cfu/g) containing the following bacterial strains: Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24, Lactococcus lactis W19 and Lactococcus lactis W58 (EcologicÂźBarrier)] in a double-blind manner for 12 weeks. Anthropometrics and cardiometabolic profiles were obtained at baseline and after 12/13 weeks of treatment.
Results: After 12/13 weeks of intervention and using intention-to-treat analysis, no difference was noted in endotoxin levels between groups [Placebo â 9.5% vs. Probiotics â 52.2%; (CI â 0.05 to 0.36; p = 0.15)]. Compared with the placebo group however, participants in the probiotics groups had a significant but modest improvement in WHR [Placebo 0.0% vs. Probiotics 1.11%; (CI â 0.12 to â 0.01; p = 0.02)] as well as a clinically significant improvement in HOMA-IR [Placebo â 12.2% vs. Probiotics â 60.4%; (CI â 0.34 to â 0.01; p = 0.04)].
Conclusion: Using a multi-strain probiotic supplement daily for 12/13 weeks significantly improved HOMA-IR and modestly reduced abdominal adiposity among medication naĂŻve T2DM patients
Experimental characterization of an ORC (organic Rankine cycle) for power and CHP (combined heat and power) applications from low grade heat sources
An ORC (organic Rankine cycle) module, designed and built for a specific CHP (combined heat and power)) application, is tested in this paper. The aim of the work is to characterize the system performance in the operating range allowed by the ORC. For this purpose, a test procedure has been conducted in a test bench. The heat source has been simulated through a natural gas boiler and a thermal oil heat transfer loop to control the temperature in the low grade range of 90 °C 150 °C. The heat sink has been developed using a dry cooler to control the hot water temperature in the range of 30 °C, corresponding to a power application, to 80 °C, of a small-scale CHP application that provides hot water at 90 °C. Thereby, the results show that the thermal power captured by the ORC, electricity and useful heat produced, increase with the rise of the thermal oil temperature and larger pressure ratios. Moreover, the expander electrical isentropic effectiveness is maximized about 70% for a pressure ratio suitable for a CHP system. The cycle efficiency slightly continues increasing for higher pressure ratios, up to a net electrical efficiency of about 8%.The authors want to acknowledge all the invaluable cooperation of Rank (R), the ORC manufacturer, for its support in this project. Also to thank greatly the Jaume I University for its financial support under the PhD grant PREDOC/2013/28 of 'Convocatoria d'ajudes predoctorals per a la formacio de personal investigador del Pla de promocio de la investigacio de la Universitat Jaume I de Castello (Spain)'.Peris Pérez, B.; Navarro Esbri, J.; Molés Ribera, F.; Gonzålez, M.; Mota Babiloni, A. (2015). Experimental characterization of an ORC (organic Rankine cycle) for power and CHP (combined heat and power) applications from low grade heat sources. Energy. 82:269-276. https://doi.org/10.1016/j.energy.2015.01.037S2692768
Recombinant production of plant lectins in microbial systems for biomedical application â the frutalin case study
Frutalin is a homotetrameric partly-glycosylated alpha-D-galactose-binding lectin of biomedical interest from Artocarpus incisa (breadfruit) seeds, belonging to the jacalin-related lectins family. As other plant lectins, frutalin is a heterogeneous mixture of several isoforms possibly with distinct biological activities. The main problem of using such lectins as biomedical tools is that âbatch-to-batchâ variation in isoforms content may lead to inconstant results. The production of lectins by recombinant means has the advantage of obtaining high amounts of proteins with defined amino-acid sequences and more precise properties. In this mini review, we provide the strategies followed to produce two different forms of frutalin in two different microbial systems: Escherichia coli and Pichia pastoris. The processing and functional properties of the recombinant frutalin obtained from these hosts are compared to those of frutalin extracted from breadfruit. Emphasis is given particularly to recombinant frutalin produced in P. pastoris, which showed a remarkable capacity as biomarker of human prostate cancer and as apoptosis-inducer of cancer cells. Recombinant frutalin production opens perspectives for its development as a new tool in human medicine.(undefined
Recombinant human erythropoietin increases survival and reduces neuronal apoptosis in a murine model of cerebral malaria
<p>Abstract</p> <p>Background</p> <p>Cerebral malaria (CM) is an acute encephalopathy with increased pro-inflammatory cytokines, sequestration of parasitized erythrocytes and localized ischaemia. In children CM induces cognitive impairment in about 10% of the survivors. Erythropoietin (Epo) has â besides of its well known haematopoietic properties â significant anti-inflammatory, antioxidant and anti-apoptotic effects in various brain disorders. The neurobiological responses to exogenously injected Epo during murine CM were examined.</p> <p>Methods</p> <p>Female C57BL/6j mice (4â6 weeks), infected with <it>Plasmodium berghei </it>ANKA, were treated with recombinant human Epo (rhEpo; 50â5000 U/kg/OD, i.p.) at different time points. The effect on survival was measured. Brain pathology was investigated by TUNEL (Terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-digoxigenin nick end labelling), as a marker of apoptosis. Gene expression in brain tissue was measured by real time PCR.</p> <p>Results</p> <p>Treatment with rhEpo increased survival in mice with CM in a dose- and time-dependent manner and reduced apoptotic cell death of neurons as well as the expression of pro-inflammatory cytokines in the brain. This neuroprotective effect appeared to be independent of the haematopoietic effect.</p> <p>Conclusion</p> <p>These results and its excellent safety profile in humans makes rhEpo a potential candidate for adjunct treatment of CM.</p
Accreting Millisecond X-Ray Pulsars
Accreting Millisecond X-Ray Pulsars (AMXPs) are astrophysical laboratories
without parallel in the study of extreme physics. In this chapter we review the
past fifteen years of discoveries in the field. We summarize the observations
of the fifteen known AMXPs, with a particular emphasis on the multi-wavelength
observations that have been carried out since the discovery of the first AMXP
in 1998. We review accretion torque theory, the pulse formation process, and
how AMXP observations have changed our view on the interaction of plasma and
magnetic fields in strong gravity. We also explain how the AMXPs have deepened
our understanding of the thermonuclear burst process, in particular the
phenomenon of burst oscillations. We conclude with a discussion of the open
problems that remain to be addressed in the future.Comment: Review to appear in "Timing neutron stars: pulsations, oscillations
and explosions", T. Belloni, M. Mendez, C.M. Zhang Eds., ASSL, Springer;
[revision with literature updated, several typos removed, 1 new AMXP added
Food effects on statolith composition of the common cuttlefish (Sepia officinalis)
The concentration of trace elements within cephalopod statoliths can provide a record of the environmental characteristics at the time of calcification. To reconstruct accurately the environmental characteristics at the time of calcification, it is important to understand the influence of as many factors as possible. To test the hypothesis that the elemental composition of cuttlefish statoliths could be influenced by diet, juvenile Sepia officinalis were fed either shrimp Crangon sp. or fish Clupea harengus under equal temperature and salinity regimes in laboratory experiments. Element concentrations in different regions of the statoliths (coreâlateral domeârostrum) were determined using laser ablation inductively coupled plasma mass spectrometry (LA- ICPMS). The ratios of Sr/Ca, Ba/Ca, Mn/Ca and Y/Ca in the statolithâs lateral dome of shrimp-fed cuttlefish were significantly higher than in the statolithâs lateral dome of fish-fed cuttlefish. Moreover, significant differences between statolith regions were found for all analysed elements. The fact that diet adds a considerable variation especially to Sr/Ca and Ba/Ca must be taken into account in future micro-chemical statolith studies targeting cephalopodâs life history
From Boatyard to Museum: 3D laser scanning and digital modelling of the Qatar Museums watercraft collection, Doha, Qatar
This is the final version of the article. Available from Wiley via the DOI in this record.This article presents the results of a project to 3D laser scan and digitally model 14 watercraft from the Qatar Museums collection, comprising a range of regional vessels: most had not been surveyed previously. The project used the resulting point clouds generated 2D naval lines and orthographic records of the vessels in their current condition, and photorealistic 3D digital models for gallery display. This case study provides illustrative examples of the intermediate stages and final outputs. It assesses the pros and cons of 3D laser scanning as a survey technology for nautical scholars in terms of the time, cost, and skillset, as well as logistical considerations. It also compares the accuracy of traditional hand survey methods.We wish to thank QM for enabling and funding this research (Grant number SL-05894)
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at â s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fbâ1 of â s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Observation of associated near-side and away-side long-range correlations in âsNN=5.02ââTeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (ÎÏ) and pseudorapidity (Îη) are measured in âsNN=5.02ââTeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1ââÎŒb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Îη|<5) ânear-sideâ (ÎÏâŒ0) correlation that grows rapidly with increasing ÎŁETPb. A long-range âaway-sideâ (ÎÏâŒÏ) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Îη and ÎÏ) and ÎŁETPb dependence. The resultant ÎÏ correlation is approximately symmetric about Ï/2, and is consistent with a dominant cosâĄ2ÎÏ modulation for all ÎŁETPb ranges and particle pT
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