Hexane Extracts of Calophyllum brasiliense Inhibit the Development of Gastric Preneoplasia in Helicobacter felis Infected INS-Gas Mice

Objectives: Indigenous Latin American populations have used extracts from Calophyllum brasiliense, a native hardwood, to treat gastrointestinal symptoms for generations. The hexane extract of Calophyllum brasiliense stem bark (HECb) protects against ethanol-mediated gastric ulceration in Swiss–Webster mice. We investigated whether HECb inhibits the development of gastric epithelial pathology following Helicobacter felis infection of INS-Gas mice. Materials and Methods: Groups of five male, 6-week-old INS-Gas mice were colonized with H. felis by gavage. From 2 weeks after colonization their drinking water was supplemented with 2% Tween20 (vehicle), low dose HECb (33 mg/L, lHECb) or high dose HECb (133 mg/L, hHECb). Equivalent uninfected groups were studied. Animals were culled 6 weeks after H. felis colonization. Preneoplastic pathology was quantified using established histological criteria. Gastric epithelial cell turnover was quantified by immunohistochemistry for Ki67 and active-caspase 3. Cytokines were quantified using an electrochemiluminescence assay. Results: Vehicle-treated H. felis infected mice exhibited higher gastric atrophy scores than similarly treated uninfected mice (mean atrophy score 5.6 ± 0.87 SEM vs. 2.2 ± 0.58, p < 0.01). The same pattern was observed following lHECb. Following hHECb treatment, H. felis status did not significantly alter atrophy scores. Gastric epithelial apoptosis was not altered by H. felis or HECb administration. Amongst vehicle-treated mice, gastric epithelial cell proliferation was increased 2.8-fold in infected compared to uninfected animals (p < 0.01). Administration of either lHECb or hHECb reduced proliferation in infected mice to levels similar to uninfected mice. A Th17 polarized response to H. felis infection was observed in all infected groups. hHECb attenuated IFN-γ, IL-6, and TNF production following H. felis infection [70% (p < 0.01), 67% (p < 0.01), and 41% (p < 0.05) reduction vs. vehicle, respectively]. Conclusion: HECb modulates gastric epithelial pathology following H. felis infection of INS-Gas mice. Further studies are indicated to confirm the mechanisms underlying these observations

Right ventricular outflow tract tachycardia worsened during pregnancy

We report the case of a 35 years old woman without underlying heart disease who was diagnosed with a right ventricular outflow tract tachycardia worsened during pregnancy. The diagnosis of ventricular tachycardia was made early in her pregnancy course but the patient had symptoms three months earlier. Her disease course was marked by rhythmic storms during the second trimester of pregnancy that led to three hospitalizations accounting for about two weeks in total. The combination of nadolol 80 mg and flecainide tablets 150 mg improved her rhythmic storms. Radiofrequency allowed a radical cure of this ventricular tachycardia. The patient is now asymptomatic 27 months after radiofrequency treatment

Los estudios de caso

[spa] Este documento de trabajo aborda tres temáticas con relación a los estudios de caso. En primer lugar, define el concepto "estudios de caso" desde los autores y fuentes más relevantes. En esta conceptualización se incluyen sus rasgos más importantes y se describen diferentes modalidades (intrínsecos, instrumentales y colectivos). En segundo lugar, se introduce la estructura conceptual del caso, es decir, la construcción de "issues" o cuestiones problemáticas, que son objeto de estudio. Por último, se reflexiona acerca de la dimensión ética en los estudios de caso y se describen los criterios éticos fundamentales para la investigación interpretativa.[cat] El document de treball que presentem aquí planteja tres temàtiques en relació als estudis de cas. En primer lloc, defineix el concepte "estudis de cas" des dels autors i les fonts més rellevants, en la conceptualització s'inclouen els trets més importants i se'n descriuen diferents modalitats (intrínseques, instrumentals i col·lectives). En segon lloc, s'introdueix l'estructura conceptual del cas, és a dir, la construcció de "issues" o qüestions problemàtiques, que són objecte d'estudi. Per últim, es reflexiona sobre la dimensió ètica en els estudis de cas i es descriuen els criteris ètics fonamentals per a la investigació interpretativa.[eng] This working document introduces three elements related to case studies. First, it brings together the most relevant authors and sources in the field to arrive at a definition of the concept "case study". This conceptualization discusses the more important characteristics of a case study, and describes different possible modalities (intrinsic, instrumental and collective). Second, it presents the conceptual structure of a case, in other words, the way in which one detects key issues and defines the object of study. Finally, the document reflects on the ethical dimension of case studies and describes fundamental ethical criteria for an interpretative investigation

IMECE2002-39444 ION ENGINE AND HALL THRUSTER DEVELOPMENT AT THE NASA GLENN RESEARCH CENTER

ABSTRACT NASA&apos;s Glenn Research Center has been selected to lead development of NASA&apos;s Evolutionary Xenon Thruster (NEXT) system. The central feature of the NEXT system is an electric propulsion thruster (EPT) that inherits the knowledge gained through the NSTAR thruster that successfully propelled Deep Space 1 to asteroid Braille and comet Borrelly, while significantly increasing the thruster power level and making improvements in performance parameters associated with NSTAR. The EPT concept under development has a 40 cm beam diameter, twice the effective area of the Deep-Space 1 thruster, while maintaining a relatively-small volume. It incorporates mechanical features and operating conditions to maximize the design heritage established by the flight NSTAR 30 cm engine, while incorporating new technology where warranted to extend the power and throughput capability. The NASA Hall thruster program currently supports a number of tasks related to high power thruster development for a number of customers including the Energetics Program (formerly called the Space-based Program), the Space Solar Power Program, and the In-space Propulsion Program. In program year 2002, two tasks were central to the NASA Hall thruster program: 1.) the development of a laboratory Hall thruster capable of providing high thrust at high power; 2.) investigations into operation of Hall thrusters at high specific impulse. In addition to these two primary thruster development activities, there are a number of other on-going activities supported by the NASA Hall thruster program. These additional activities are related to issues such as thruster lifetime and spacecraft integration. INTRODUCTION The success of the NASA Solar Electric Propulsion Technology Applications Readiness (NSTAR) program io

El acceso abierto al conocimiento científico

[cat] En aquest document es descriuen i s'analitzen els conceptes fonamentals relacionats amb l'accés obert al coneixement científic. En primer lloc, es presenta una breu història dels drets d'autor i del copyright (tots esl drets reservats) fins avui. Avui la digitalització ha donat pas a un nou model de llicències copyleft (alguns drets reservats). S'ofereixen respostes a les preguntes més freqüents sobre l'aplicació dels drets d'autor en e l'àmbit acadèmic i la investigació. Es presenten dos models de llicències copyleft: Creative Commons i les llicències d'Universitat (Harvard). A través de diferents declaracions (Budapest, Bethesda i Berlín) es defineixen els principis i acords internacionals en matèria d'accés obert a la comunitat científica i acadèmica en la darrera dècada. Finalment, es defineix el concepte d'"Educació OOberta" i es descriu el paper dels Repositoris Institucionals en l'enmagatzament i difusió del coneixement científic i acadèmic.[spa] En este documento se describen y analizan conceptos fundamentales relacionados con el acceso abierto al conocimiento científico. En primer lugar, se presenta una breve historia del derecho de autor y el copyright (todos los derechos reservados) hasta la actualidad, donde la digitalización ha dado paso a un nuevo modelo de licencias «copyleft» (algunos derechos reservados). Se ofrecen respuestas a las preguntas más comunes sobre la aplicación de los derechos de autor en la academia y la investigación. Se presentan dos modelos de licencias copyleft: Creative Commons y las «Licencias de Universidad» (Harvard). A través de diferentes Declaraciones (Budapest, Bethesda y Berlín) se definen los principios y acuerdos internacionales en materia de acceso abierto en la comunidad científica y académica en la última década. Por último, se define el concepto de «Educación Abierta» y se describe el papel de los Repositorios Institucionales en el almacenamiento y difusión del conocimiento científico y académico.[eng] This document describes and analyses fundamental concepts related to the open access of scientific knowledge. First, it presents a brief history of copyright (all rights reserved) through today, where digitalisation has taken a step towards a new "copyleft model (some rights reserved). It provides answers to the most common questions related to copyright in scientific research and academic fields. The paper also presents two models of copyleft licenses: Creative Commons and the "University Licences" (Harvard). By drawing on different declarations (Budapest, Bethesda and Berlin), it defines the principles and international agreements regarding open access material in the scientific community for the last decade. Finally, the paper will define a concept of "Open Education", and describe the role of Institutional Repositories in the storage and dissemination of academic and scientific knowledge

Magnetic microwires as macrospins in a long-range dipole-dipole interaction

The long-range dipole-dipole interaction in an array of ferromagnetic microwires is studied through magnetic hysteresis measurements and Monte Carlo simulation. The experimental study has been performed on glass-coated amorphous Fe77.5Si7.5B15 microwire with diameter of 5 mu m and lengths from 5 to 60 mm. Hysteresis loops performed at room temperature for an array of N microwires (N = 2, 3, 3, and 5) exhibit jumps and plateaux on the demagnetization, each step correspondent to the magnetization reversal of an individual wire. A model has been constructed taking into account the fact that the magnetization reversal is nucleated at the ends of each wire, under the influence of a dipolar field due to all other wires. Measurements for two wires allowed us to conclude that the dipolar field (or constant coupling) is independent of distance, at least for an array of a few wires. With the exception of three wires, where frustration seems to be present, the predicted reversal fields of our model are in good agreement with measurements. Ln order to study the role played by the number of wires on the demagnetization process, we calculate hysteresis loops for a large number of wires through the Monte Carlo method.61138976898

Complex picture for likelihood of ENSO-driven flood hazard

El Niño and La Niña events, the extremes of ENSO climate variability, influence river flow and flooding at the global scale. Estimates of the historical probability of extreme (high or low) precipitation are used to provide vital information on the likelihood of adverse impacts during extreme ENSO events. However, the nonlinearity between precipitation and flood magnitude motivates the need for estimation of historical probabilities using analysis of hydrological datasets. Here, this analysis is undertaken using the ERA-20CM-R river flow reconstruction for the 20th Century. Our results show that the likelihood of increased or decreased flood hazard during ENSO events is much more complex than is often perceived and reported; probabilities vary greatly across the globe, with large uncertainties inherent in the data and clear differences when comparing the hydrological analysis to precipitation

Effective field theory analysis of the first LUX dark matter search

The Large Underground Xenon (LUX) dark matter search was a 250-kg active mass dual-phase time projection chamber that operated by detecting light and ionization signals from particles incident on a xenon target. In December 2015, LUX reported a minimum 90% upper C.L. of 6×10-46 cm2 on the spin-independent WIMP-nucleon elastic scattering cross section based on a 1.4×104 kg·day exposure in its first science run. Tension between experiments and the absence of a definitive positive detection suggest it would be prudent to search for WIMPs outside the standard spin-independent/spin-dependent paradigm. Recent theoretical work has identified a complete basis of 14 independent effective field theory (EFT) operators to describe WIMP-nucleon interactions. In addition to spin-independent and spin-dependent nuclear responses, these operators can produce novel responses such as angular-momentum-dependent and spin-orbit couplings. Here we report on a search for all 14 of these EFT couplings with data from LUX's first science run. Limits are placed on each coupling as a function of WIMP mass

Investigation of background electron emission in the LUX detector

Dual-phase xenon detectors, as currently used in direct detection dark matter experiments, have observed elevated rates of background electron events in the low energy region. While this background negatively impacts detector performance in various ways, its origins have only been partially studied. In this paper we report a systematic investigation of the electron pathologies observed in the LUX dark matter experiment. We characterize different electron populations based on their emission intensities and their correlations with preceding energy depositions in the detector. By studying the background under different experimental conditions, we identified the leading emission mechanisms, including photoionization and the photoelectric effect induced by the xenon luminescence, delayed emission of electrons trapped under the liquid surface, capture and release of drifting electrons by impurities, and grid electron emission. We discuss how these backgrounds can be mitigated in LUX and future xenon-based dark matter experiments

First direct detection constraint on mirror dark matter kinetic mixing using LUX 2013 data

We present the results of a direct detection search for mirror dark matter interactions, using data collected from the Large Underground Xenon experiment during 2013, with an exposure of 95 live-days × 118 kg. Here, the calculations of the mirror electron scattering rate in liquid xenon take into account the shielding effects from mirror dark matter captured within the Earth. Annual and diurnal modulation of the dark matter flux and atomic shell effects in xenon are also accounted for. Having found no evidence for an electron recoil signal induced by mirror dark matter interactions we place an upper limit on the kinetic mixing parameter over a range of local mirror electron temperatures between 0.1 and 0.6 keV. This limit shows significant improvement over the previous experimental constraint from orthopositronium decays and significantly reduces the allowed parameter space for the model. We exclude mirror electron temperatures above 0.3 keV at a 90% confidence level, for this model, and constrain the kinetic mixing below this temperature