3,286 research outputs found
The dual-function glutamate transporters: structure and molecular characterisation of the substrate-binding sites
AbstractGlutamate transporters are essential for terminating synaptic excitation and for maintaining extracellular glutamate concentrations below neurotoxic levels. These transporters also mediate a thermodynamically uncoupled chloride flux, activated by two of the molecules they transport, sodium and glutamate. Five eukaryotic glutamate transporters have been cloned and identified. They exhibit ∼50% identity and this homology is even greater at the carboxyl terminal half, which is predicted to have an unusual topology. Determination of the topology shows that the carboxyl terminal part contains several transmembrane domains separated by two reentrant loops that are in close proximity to each other. We have identified several conserved amino acid residues in the carboxyl terminal half that play crucial roles in the interaction of the transporter with its substrates: sodium, potassium and glutamate. The conformation of the transporter gating the anion conductance is different from that during substrate translocation. However, there exists a dynamic equilibrium between these conformations
Enhancing gravitational wave astronomy with galaxy catalogues
Joint gravitational wave (GW) and electromagnetic (EM) observations, as a key
research direction in multi-messenger astronomy, will provide deep insight into
the astrophysics of a vast range of astronomical phenomena. Uncertainties in
the source sky location estimate from gravitational wave observations mean
follow-up observatories must scan large portions of the sky for a potential
companion signal. A general frame of joint GW-EM observations is presented by a
multi-messenger observational triangle. Using a Bayesian approach to
multi-messenger astronomy, we investigate the use of galaxy catalogue and host
galaxy information to reduce the sky region over which follow-up observatories
must scan, as well as study its use for improving the inclination angle
estimates for coalescing binary compact objects. We demonstrate our method
using a simulated neutron stars inspiral signal injected into simulated
Advanced detectors noise and estimate the injected signal sky location and
inclination angle using the Gravitational Wave Galaxy Catalogue. In this case
study, the top three candidates in rank have , and posterior
probability of being the host galaxy, receptively. The standard deviation of
cosine inclination angle (0.001) of the neutron stars binary using
gravitational wave-galaxy information is much smaller than that (0.02) using
only gravitational wave posterior samples.Comment: Proceedings of the Sant Cugat Forum on Astrophysics. 2014 Session on
'Gravitational Wave Astrophysics
Infant colic: from theory to practice
Infant colic is one of the most common, yet least studied, functional disorders of the gastrointestinal tract. Until now, there is no certainty both in the understanding of the nature of this condition and in the approaches to its correction. At the same time, infant crying is of concern to parents, forcing them to seek professional help and incur considerable medical expenses and to resort, sometimes unreasonably, to dietary and medical corrections. This article provides information on the etiology, pathogenesis and management of infantile colic from an evidence-based perspective, based on a review of the current literature. Various preconditions for the occurrence and development of infantile colic are analysed in detail, none of which can affect all occurrences. Evidence for the proven efficacy of including Lactobacillus reuteri in the treatment of intestinal colic in infants is presented. Effects on the gastrointestinal tract microbiome can be of undeniable benefit. Lactobacillus reuteri is one of the most studied and scientifically documented probiotics. 203 completed clinical trials involving 17,200 participants, including 67 trials involving 8,200 participants between 0 and 3 years of age. Numerous placebo-controlled studies have shown that taking Lactobacillus reuteri DSM 17938 can significantly reduce crying time in infants with colic, and in these studies, rates of 50% or more reduction in crying time were 2.3 times higher compared to controls
Is it possible to enhance immune response after vaccination? The role of a probiotic with a proven positive effect on all components of the immune system
Preventive vaccination is currently the most affordable and economical way to reduce morbidity and mortality from many infections, improve quality and human life expectancy with an almost ideal balance of benefits and risks among all medical procedures. The article deals with the reasons for variability of the immune response caused by vaccines, between individuals and between populations, which is of fundamental importance for human health. The authors have presented data indicating a key role of the gut microbiota in the control of the immune response to vaccination. Particular attention is paid to the microbial diversity in different loci of the body. The role of microorganisms in the proper functioning of the body and the formation of a number of pathological conditions is described. Most modern vaccines are live-attenuated, killed / inactivated or subunit (recombinant) vaccines, and they are designed for the parenteral route of administration. Most of these vaccines elicit a weak immune response, especially in the mucous membranes, due to the route of administration and are associated with weak cell-mediated immunity. Therefore, mechanisms that can enhance virus-specific vaccine immunity in infants and children are required, such as the use of more potent or selective immunity-enhancing adjuvants. Some probiotic strains may be considered as promising vaccine adjuvants. This article evaluates the recent clinical studies of probiotics used to enhance vaccine-specific immunity in adults and infants. The present-day knowledge on the role of the probiotic strain Lactobacillus rhamnosus GG with the aim of activating immunity after vaccination are presented
Electromagnetic follow-up of gravitational wave transient signal candidates
Pioneering efforts aiming at the development of multi-messenger gravitational
wave and electromagnetic astronomy have been made. An electromagnetic
observation follow-up program of candidate gravitational wave events has been
performed (Dec 17 2009 to Jan 8 2010 and Sep 4 to Oct 20 2010) during the
recent runs of the LIGO and Virgo gravitational wave detectors. It involved
ground-based and space electromagnetic facilities observing the sky at optical,
X-ray and radio wavelengths. The joint gravitational wave and electromagnetic
observation study requires the development of specific image analysis
procedures able to discriminate the possible electromagnetic counterpart of
gravitational wave triggers from contaminant/background events. The paper
presents an overview of the electromagnetic follow-up program and the image
analysis procedures.Comment: Proceedings of the 12th International Conference on "Topics in
Astroparticle and Underground Physics" (TAUP 2011), Munich, September 2011
(to appear in IoP Journal of Physics: Conference Series
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The effects of 800 MeV proton irradiation on the corrosion of tungsten, tantalum, stainless steel, and gold
Real time electrochemical data were acquired for tungsten, tantalum, stainless steel 304L, and gold targets during proton irradiation at the LANSCE Weapons Neutron Research Facility. The goal of this research was to establish a better understanding of the corrosion properties of materials as a function of proton irradiation and gain insight into the mechanism of the observed phenomena. The following electrochemical observations were made during proton irradiation of W, Ta, SS304, and Au: (1) the open circuit potential of all materials increased with increasing proton fluence; (2) the corrosion rate (at the OCP) of W and SS304 increased with increasing proton fluence; (3) the passive dissolution rate for SS304 and Ta decreased with increasing proton fluence; (4) the anodic dissolution rate for W increased with increasing proton fluence; (5) the pitting potential for SS304 increased with proton fluence, which is an indication that the material is less susceptible to pitting attack during irradiation
Selective Metal Cation Capture by Soft Anionic Metal-Organic Frameworks via Drastic Single-Crystal-to-Single-Crystal Transformations
In this paper we describe a novel framework for the discovery of the topical
content of a data corpus, and the tracking of its complex structural changes
across the temporal dimension. In contrast to previous work our model does not
impose a prior on the rate at which documents are added to the corpus nor does
it adopt the Markovian assumption which overly restricts the type of changes
that the model can capture. Our key technical contribution is a framework based
on (i) discretization of time into epochs, (ii) epoch-wise topic discovery
using a hierarchical Dirichlet process-based model, and (iii) a temporal
similarity graph which allows for the modelling of complex topic changes:
emergence and disappearance, evolution, and splitting and merging. The power of
the proposed framework is demonstrated on the medical literature corpus
concerned with the autism spectrum disorder (ASD) - an increasingly important
research subject of significant social and healthcare importance. In addition
to the collected ASD literature corpus which we will make freely available, our
contributions also include two free online tools we built as aids to ASD
researchers. These can be used for semantically meaningful navigation and
searching, as well as knowledge discovery from this large and rapidly growing
corpus of literature.Comment: In Proc. Pacific-Asia Conference on Knowledge Discovery and Data
Mining (PAKDD), 201
Using ISS Telescopes for Electromagnetic Follow-up of Gravitational Wave Detections of NS-NS and NS-BH Mergers
The International Space Station offers a unique platform for rapid and inexpensive deployment of space telescopes. A scientific opportunity of great potential later this decade is the use of telescopes for the electromagnetic follow-up of ground-based gravitational wave detections of neutron star and black hole mergers. We describe this possibility for OpTIIX, an ISS technology demonstration of a 1.5 m diffraction limited optical telescope assembled in space, and ISS-Lobster, a wide-field imaging X-ray telescope now under study as a potential NASA mission. Both telescopes will be mounted on pointing platforms, allowing rapid positioning to the source of a gravitational wave event. Electromagnetic follow-up rates of several per year appear likely, offering a wealth of complementary science on the mergers of black holes and neutron stars
Deaf children's understanding of emotions: desires take precedence
Deaf children frequently have trouble understanding other people's emotions. It has been suggested that an impaired theory of mind can account for this. This research focused on the spontaneous use of mental states in explaining other people's emotions by 6- and 10-year-old deaf children as compared to their hearing peers. Within both age-groups deaf children referred to others' beliefs as often as their hearing peers and their references to desires even exceeded those of hearing children. This relative priority for the expression of desires is discussed in terms of possible communicative patterns of deaf children. The specific problems that deaf children meet in their daily communication might explain their abundance of desire-references: plausibly, they give a high priority to stress their own desires and needs unambiguously
LOOC UP: Locating and observing optical counterparts to gravitational wave bursts
Gravitational wave (GW) bursts (short duration signals) are expected to be
associated with highly energetic astrophysical processes. With such high
energies present, it is likely these astrophysical events will have signatures
in the EM spectrum as well as in gravitational radiation. We have initiated a
program, "Locating and Observing Optical Counterparts to Unmodeled Pulses in
Gravitational Waves" (LOOC UP) to promptly search for counterparts to GW burst
candidates. The proposed method analyzes near real-time data from the
LIGO-Virgo network, and then uses a telescope network to seek optical-transient
counterparts to candidate GW signals. We carried out a pilot study using
S5/VSR1 data from the LIGO-Virgo network to develop methods and software tools
for such a search. We will present the method, with an emphasis on the
potential for such a search to be carried out during the next science run of
LIGO and Virgo, expected to begin in 2009.Comment: 11 pages, 2 figures; v2) added acknowledgments, additional
references, and minor text changes v3) added 1 figure, additional references,
and minor text changes. v4) Updated references and acknowledgments. To be
published in the GWDAW 12 Conf. Proc. by Classical and Quantum Gravit
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