315 research outputs found
Intestinal microbiota influences non-intestinal related autoimmune diseases
Indexación: Scopus.The human body is colonized by millions of microorganisms named microbiota that interact with our tissues in a cooperative and non-pathogenic manner. These microorganisms are present in the skin, gut, nasal, oral cavities, and genital tract. In fact, it has been described that the microbiota contributes to balancing the immune system to maintain host homeostasis. The gut is a vital organ where microbiota can influence and determine the function of cells of the immune system and contributes to preserve the wellbeing of the individual. Several articles have emphasized the connection between intestinal autoimmune diseases, such as Crohn's disease with dysbiosis or an imbalance in the microbiota composition in the gut. However, little is known about the role of the microbiota in autoimmune pathologies affecting other tissues than the intestine. This article focuses on what is known about the role that gut microbiota can play in the pathogenesis of non-intestinal autoimmune diseases, such as Grave's diseases, multiple sclerosis, type-1 diabetes, systemic lupus erythematosus, psoriasis, schizophrenia, and autism spectrum disorders. Furthermore, we discuss as to how metabolites derived from bacteria could be used as potential therapies for non-intestinal autoimmune diseases. © 2018 Opazo, Ortega-Rocha, Coronado-Arrázola, Bonifaz, Boudin, Neunlist, Bueno, Kalergis and Riedel.https://www.frontiersin.org/articles/10.3389/fmicb.2018.00432/ful
Detection of interstellar hydrogen peroxide
The molecular species hydrogen peroxide, HOOH, is likely to be a key
ingredient in the oxygen and water chemistry in the interstellar medium. Our
aim with this investigation is to determine how abundant HOOH is in the cloud
core {\rho} Oph A. By observing several transitions of HOOH in the
(sub)millimeter regime we seek to identify the molecule and also to determine
the excitation conditions through a multilevel excitation analysis. We have
detected three spectral lines toward the SM1 position of {\rho} Oph A at
velocity-corrected frequencies that coincide very closely with those measured
from laboratory spectroscopy of HOOH. A fourth line was detected at the
4{\sigma} level. We also found through mapping observations that the HOOH
emission extends (about 0.05 pc) over the densest part of the {\rho} Oph A
cloud core. We derive an abundance of HOOH relative to that of H_2 in the SM1
core of about 1\times10^(-10). To our knowledge, this is the first reported
detection of HOOH in the interstellar medium.Comment: 5 pages, 4 figures, accepted for publication in Astronomy &
Astrophysics, new version corrects a typo in Table 1 (and consequently in Fig
4
Formation and Propagation of Discontinuity for Boltzmann Equation in Non-Convex Domains
The formation and propagation of singularities for Boltzmann equation in
bounded domains has been an important question in numerical studies as well as
in theoretical studies. Consider the nonlinear Boltzmann solution near
Maxwellians under in-flow, diffuse, or bounce-back boundary conditions. We
demonstrate that discontinuity is created at the non-convex part of the grazing
boundary, then propagates only along the forward characteristics inside the
domain before it hits on the boundary again.Comment: 39 pages, 5 Figure
Sr2V3O9 and Ba2V3O9: quasi one-dimensional spin-systems with an anomalous low temperature susceptibility
The magnetic behaviour of the low-dimensional Vanadium-oxides Sr2V3O9 and
Ba2V3O9 was investigated by means of magnetic susceptibility and specific heat
measurements. In both compounds, the results can be very well described by an
S=1/2 Heisenberg antiferromagnetic chain with an intrachain exchange of J = 82
K and J = 94 K in Sr2V3O9 and Ba2V3O9, respectively. In Sr2V3O9,
antiferromagnetic ordering at T_N = 5.3 K indicate a weak interchain exchange
of the order of J_perp ~ 2 K. In contrast, no evidence for magnetic order was
found in Ba2V3O9 down to 0.5 K, pointing to an even smaller interchain
coupling. In both compounds, we observe a pronounced Curie-like increase of the
susceptibility below 30 K, which we tentatively attribute to a staggered field
effect induced by the applied magnetic field. Results of LDA calculations
support the quasi one-dimensional character and indicate that in Sr2V3O9, the
magnetic chain is perpendicular to the structural one with the magnetic
exchange being transferred through VO4 tetrahedra.Comment: Submitted to Phy. Rev.
Laboratory evidence for efficient water formation in interstellar ices
Even though water is the main constituent in interstellar icy mantles, its
chemical origin is not well understood. Three different formation routes have
been proposed following hydrogenation of O, O2, or O3, but experimental
evidence is largely lacking. We present a solid state astrochemical laboratory
study in which one of these routes is tested. For this purpose O2 ice is
bombarded by H- or D-atoms under ultra high vacuum conditions at astronomically
relevant temperatures ranging from 12 to 28 K. The use of reflection absorption
infrared spectroscopy (RAIRS) permits derivation of reaction rates and shows
efficient formation of H2O (D2O) with a rate that is surprisingly independent
of temperature. This formation route converts O2 into H2O via H2O2 and is found
to be orders of magnitude more efficient than previously assumed. It should
therefore be considered as an important channel for interstellar water ice
formation as illustrated by astrochemical model calculations.Comment: 15 pages, 4 figures. ApJ, in pres
Analysis and modelling of tsunami-induced tilt for the 2007, M = 7.6, Tocopilla and the 2010, M = 8.8 Maule earthquakes, Chile, from long-base tiltmeter and broadband seismometer records
We present a detailed study of tsunami-induced tilt at in-land sites, to test the interest and feasibility of such analysis for tsunami detection and modelling. We studied tiltmeter and broadband seismometer records of northern Chile, detecting a clear s
Global existence and full regularity of the Boltzmann equation without angular cutoff
We prove the global existence and uniqueness of classical solutions around an
equilibrium to the Boltzmann equation without angular cutoff in some Sobolev
spaces. In addition, the solutions thus obtained are shown to be non-negative
and in all variables for any positive time. In this paper, we study
the Maxwellian molecule type collision operator with mild singularity. One of
the key observations is the introduction of a new important norm related to the
singular behavior of the cross section in the collision operator. This norm
captures the essential properties of the singularity and yields precisely the
dissipation of the linearized collision operator through the celebrated
H-theorem
High Resolution Mid-Infrared Spectroscopy of NGC 7538 IRS 1: Probing Chemistry in a Massive Young Stellar Object
We present high resolution (R = 75,000-100,000) mid-infrared spectra of the
high-mass embedded young star IRS 1 in the NGC 7538 star-forming region.
Absorption lines from many rotational states of C2H2, 13C12CH2, CH3, CH4, NH3,
HCN, HNCO, and CS are seen. The gas temperature, column density, covering
factor, line width, and Doppler shift for each molecule are derived. All
molecules were fit with two velocity components between -54 and -63 km/s. We
find high column densities (~ 10e16 cm^2) for all the observed molecules
compared to values previously reported and present new results for CH3 and
HNCO. Several physical and chemical models are considered. The favored model
involves a nearly edge-on disk around a massive star. Radiation from dust in
the inner disk passes through the disk atmosphere, where large molecular column
densities can produce the observed absorption line spectrum.Comment: Accepted to ApJ, 15 pages, 8 figure
Evaluation of Rich and Explicit Feedback for Exploratory Search
A user’s goals and interests during an exploratory search task are often ambiguous and complex. When engaging with new documents, people regularly use annotations to help better understand them and make them their own. These annotations can also pro- vide rich information to gain insight into a reader’s interests. In particular, it is possible to use highlights as a richer form of feed- back compared to traditional document-level relevance feedback. We first show that this form of feedback leads to improvements in document retrieval in exploratory search tasks with simulated users when compared to relevance feedback. We then present an evaluation platform which will allow us to understand the retrieval performance, user experience, and behavioral characteristics of human subjects using highlights as feedback. Finally, we propose an experimental design with human subjects. We hope that our experimental findings will help improve current simulated user evaluations for such systems
Paintable Battery
If the components of a battery, including electrodes, separator, electrolyte and the current collectors can be designed as paints and applied sequentially to build a complete battery, on any arbitrary surface, it would have significant impact on the design, implementation and integration of energy storage devices. Here, we establish a paradigm change in battery assembly by fabricating rechargeable Li-ion batteries solely by multi-step spray painting of its components on a variety of materials such as metals, glass, glazed ceramics and flexible polymer substrates. We also demonstrate the possibility of interconnected modular spray painted battery units to be coupled to energy conversion devices such as solar cells, with possibilities of building standalone energy capture-storage hybrid devices in different configurations
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