1,830 research outputs found
The beta-Oslo method: experimentally constrained () reaction rates relevant to the -process
Unknown neutron-capture reaction rates remain a significant source of
uncertainty in state-of-the-art -process nucleosynthesis reaction network
calculations. As the -process involves highly neutron-rich nuclei for which
direct () cross-section measurements are virtually impossible,
indirect methods are called for to constrain () cross sections used
as input for the -process nuclear network. Here we discuss the newly
developed beta-Oslo method, which is capable of providing experimental input
for calculating () rates of neutron-rich nuclei. The beta-Oslo method
represents a first step towards constraining neutron-capture rates of
importance to the -process.Comment: 4 pages, 1 figure, conference proceedings Nuclei in the Cosmos XV
2018, Italy
Understanding drinking among midlife men in the United Kingdom: A systematic review of qualitative studies
Objectives This study reviews qualitative research into the sociocultural meanings and subjective experiences that midlife men in the United Kingdom (UK) associate with their drinking. In the UK, average weekly alcohol consumption is highest among midlife men, and they are disproportionately affected by alcohol harm. There is increasing recognition that public health messages to support behaviour change must be based on an in-depth understanding of drinking motivations and experiences. Study design and Methods Systematic literature review of studies exploring motivations for and experiences of drinking among UK men aged 45-60 using qualitative methodology. Medline, PsycINFO and the Social Science Citation Index were used, along with manual searches of key journals, Google searches and a call for evidence. The Critical Appraisal Skills Programme tool was used to quality-assess papers. Thematic synthesis was used to combine and analyse the data. Results From 5,172 titles and abstracts (1995-2018), 11 publications were included, representing 6 unique studies. Five themes were identified: ‘Drinking Motivations’; ‘Drinking Justifications’; ‘Drinking Strategies and Control’; ‘Social Norms and Identity’ and ‘Harm’. Motivations for drinking among midlife men were associated with relaxation, socialising and maintenance of male friendships. They justified drinking as a choice and emphasised their ability to meet responsibilities, which they contrasted with ‘problem drinkers'. Social norms governed drinking behaviours as an expression of masculinity. Conclusion This review highlights the significance of the meanings and social importance of alcohol consumption among midlife men. Interventions using information and guidance should consider these when aiming to effectively influence the way this group drinks
Impact of calcium on salivary α-amylase activity, starch paste apparent viscosity and thickness perception
Thickness perception of starch-thickened products
during eating has been linked to starch viscosity and
salivary amylase activity. Calcium is an essential cofactor
for α-amylase and there is anecdotal evidence that adding
extra calcium affects amylase activity in processes like
mashing of beer. The aims of this paper were to (1) investigate the role of salivary calcium on α-amylase
activity and (2) to measure the effect of calcium concentration on apparent viscosity and thickness perception when interacting with salivary α-amylase in starch-based samples.
α-Amylase activity in saliva samples from 28 people
was assessed using a typical starch pasting cycle (up to 95 °C). The activity of the enzyme (as measured by the change in starch apparent viscosity) was maintained by the presence of calcium, probably by protecting the enzyme from heat denaturation. Enhancement of α-amylase activity by calcium at 37 °C was also observed although to a smaller extent. Sensory analysis showed a general trend of decreased
thickness perception in the presence of calcium, but the result was only significant for one pair of samples, suggesting a limited impact of calcium enhanced enzyme activity on perceived thickness
Virtual screening for inhibitors of the human TSLP:TSLPR interaction
The pro-inflammatory cytokine thymic stromal lymphopoietin (TSLP) plays a pivotal role in the pathophysiology of various allergy disorders that are mediated by type 2 helper T cell (Th2) responses, such as asthma and atopic dermatitis. TSLP forms a ternary complex with the TSLP receptor (TSLPR) and the interleukin-7-receptor subunit alpha (IL-7Ra), thereby activating a signaling cascade that culminates in the release of pro-inflammatory mediators. In this study, we conducted an in silico characterization of the TSLP: TSLPR complex to investigate the drugability of this complex. Two commercially available fragment libraries were screened computationally for possible inhibitors and a selection of fragments was subsequently tested in vitro. The screening setup consisted of two orthogonal assays measuring TSLP binding to TSLPR: a BLI-based assay and a biochemical assay based on a TSLP: alkaline phosphatase fusion protein. Four fragments pertaining to diverse chemical classes were identified to reduce TSLP: TSLPR complex formation to less than 75% in millimolar concentrations. We have used unbiased molecular dynamics simulations to develop a Markov state model that characterized the binding pathway of the most interesting compound. This work provides a proof-ofprinciple for use of fragments in the inhibition of TSLP: TSLPR complexation
Higher Spin Gravity with Matter in AdS_3 and Its CFT Dual
We study Vasiliev's system of higher spin gauge fields coupled to massive
scalars in AdS_3, and compute the tree level two and three point functions.
These are compared to the large N limit of the W_N minimal model, and
nontrivial agreements are found. We propose a modified version of the
conjecture of Gaberdiel and Gopakumar, under which the bulk theory is
perturbatively dual to a subsector of the CFT that closes on the sphere.Comment: 58 pages; typos corrected, references adde
A Small Conductance Calcium-Activated K<sup>+</sup> Channel in C. elegans, KCNL-2, Plays a Role in the Regulation of the Rate of Egg-Laying
In the nervous system of mice, small conductance calcium-activated potassium (SK) channels function to regulate neuronal excitability through the generation of a component of the medium afterhyperpolarization that follows action potentials. In humans, irregular action potential firing frequency underlies diseases such as ataxia, epilepsy, schizophrenia and Parkinson's disease. Due to the complexity of studying protein function in the mammalian nervous system, we sought to characterize an SK channel homologue, KCNL-2, in C. elegans, a genetically tractable system in which the lineage of individual neurons was mapped from their early developmental stages. Sequence analysis of the KCNL-2 protein reveals that the six transmembrane domains, the potassium-selective pore and the calmodulin binding domain are highly conserved with the mammalian homologues. We used widefield and confocal fluorescent imaging to show that a fusion construct of KCNL-2 with GFP in transgenic lines is expressed in the nervous system of C. elegans. We also show that a KCNL-2 null strain, kcnl-2(tm1885), demonstrates a mild egg-laying defective phenotype, a phenotype that is rescued in a KCNL-2-dependent manner. Conversely, we show that transgenic lines that overexpress KCNL-2 demonstrate a hyperactive egg-laying phenotype. In this study, we show that the vulva of transgenic hermaphrodites is highly innervated by neuronal processes and by the VC4 and VC5 neurons that express GFP-tagged KCNL-2. We propose that KCNL-2 functions in the nervous system of C. elegans to regulate the rate of egg-laying. © 2013 Chotoo et al
Interleukin-1 regulates multiple atherogenic mechanisms in response to fat feeding
Background: Atherosclerosis is an inflammatory process that develops in individuals with known risk factors that include hypertension and hyperlipidaemia, influenced by diet. However, the interplay between diet, inflammatory mechanisms and vascular risk factors requires further research. We hypothesised that interleukin-1 (IL-1) signaling in the vessel wall would raise arterial blood pressure and promote atheroma.
Methodology/Principal Findings: Apoe(-/-) and Apoe(-/-)/IL-1R1(-/-) mice were fed high fat diets for 8 weeks, and their blood pressure and atherosclerosis development measured. Apoe(-/-)/IL-R1(-/-) mice had a reduced blood pressure and significantly less atheroma than Apoe(-/-) mice. Selective loss of IL-1 signaling in the vessel wall by bone marrow transplantation also reduced plaque burden (p<0.05). This was associated with an IL-1 mediated loss of endothelium-dependent relaxation and an increase in vessel wall Nox 4. Inhibition of IL-1 restored endothelium-dependent vasodilatation and reduced levels of arterial oxidative stress.
Conclusions/Significance: The IL-1 cytokine system links atherogenic environmental stimuli with arterial inflammation, oxidative stress, increased blood pressure and atherosclerosis. This is the first demonstration that inhibition of a single cytokine can block the rise in blood pressure in response to an environmental stimulus. IL-1 inhibition may have profound beneficial effects on atherogenesis in man
The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
The assembly process of our Galaxy can be retrieved using the motions and
chemistry of individual stars. Chemo-dynamical studies of the nearby halo have
long hinted at the presence of multiple components such as streams, clumps,
duality and correlations between the stars' chemical abundances and orbital
parameters. More recently, the analysis of two large stellar surveys have
revealed the presence of a well-populated chemical elemental abundance
sequence, of two distinct sequences in the colour-magnitude diagram, and of a
prominent slightly retrograde kinematic structure all in the nearby halo, which
may trace an important accretion event experienced by the Galaxy. Here report
an analysis of the kinematics, chemistry, age and spatial distribution of stars
in a relatively large volume around the Sun that are mainly linked to two major
Galactic components, the thick disk and the stellar halo. We demonstrate that
the inner halo is dominated by debris from an object which at infall was
slightly more massive than the Small Magellanic Cloud, and which we refer to as
Gaia-Enceladus. The stars originating in Gaia-Enceladus cover nearly the full
sky, their motions reveal the presence of streams and slightly retrograde and
elongated trajectories. Hundreds of RR Lyrae stars and thirteen globular
clusters following a consistent age-metallicity relation can be associated to
Gaia-Enceladus on the basis of their orbits. With an estimated 4:1 mass-ratio,
the merger with Gaia-Enceladus must have led to the dynamical heating of the
precursor of the Galactic thick disk and therefore contributed to the formation
of this component approximately 10 Gyr ago. These findings are in line with
simulations of galaxy formation, which predict that the inner stellar halo
should be dominated by debris from just a few massive progenitors.Comment: 19 pages, 8 figures. Published in Nature in the issue of Nov. 1st,
2018. This is the authors' version before final edit
First-time patellar dislocation with resultant habitual dislocation two years later, which was not demonstrated on plain X-rays halfway: a case report
We present an instructive case of habitual left patellar dislocation in which the patella had appeared odd due to lateral tilt relative to contralateral side, but had been radiologically confirmed to be on the trochlea at 1 year prior to the referral. An 11-year-old girl presented to our hospital 2 years after the left patella had dislocated with a 'giving way' when cutting to the left. Our physical and radiological examinations confirmed that the left patella was laterally tilted in the patellar groove with the knee in extension but was dislocated in flexion beyond 45°. In spite of these findings, she had been untreated at the previous hospital since all plain X-rays, including a skyline patellar view, had failed to demonstrate the dislocation. Consequently, in addition to reconstruction of medial patellofemoral ligament, she had to undergo a lateral retinacular release, which might have been unnecessary if treated earlier. This case illustrates that first-time patellar dislocation can gradually lead to habitual dislocation subsequently, and that cautious physical examinations in regard to patella tracking are essential since radiological examinations do not always reveal the pathophysiology of patellar instability
Identification of Class I HLA T Cell Control Epitopes for West Nile Virus
The recent West Nile virus (WNV) outbreak in the United States underscores the importance of understanding human immune responses to this pathogen. Via the presentation of viral peptide ligands at the cell surface, class I HLA mediate the T cell recognition and killing of WNV infected cells. At this time, there are two key unknowns in regards to understanding protective T cell immunity: 1) the number of viral ligands presented by the HLA of infected cells, and 2) the distribution of T cell responses to these available HLA/viral complexes. Here, comparative mass spectroscopy was applied to determine the number of WNV peptides presented by the HLA-A*11:01 of infected cells after which T cell responses to these HLA/WNV complexes were assessed. Six viral peptides derived from capsid, NS3, NS4b, and NS5 were presented. When T cells from infected individuals were tested for reactivity to these six viral ligands, polyfunctional T cells were focused on the GTL9 WNV capsid peptide, ligands from NS3, NS4b, and NS5 were less immunogenic, and two ligands were largely inert, demonstrating that class I HLA reduce the WNV polyprotein to a handful of immune targets and that polyfunctional T cells recognize infections by zeroing in on particular HLA/WNV epitopes. Such dominant HLA/peptide epitopes are poised to drive the development of WNV vaccines that elicit protective T cells as well as providing key antigens for immunoassays that establish correlates of viral immunity. © 2013 Kaabinejadian et al
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