171 research outputs found

    Novel types of anti-ecloud surfaces

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    In high power RF devices for space, secondary electron emission appears as the main parameter governing the multipactor effect and as well as the e-cloud in large accelerators. Critical experimental activities included development of coatings with low secondary electron emission yield (SEY) for steel (large accelerators) and aluminium (space applications). Coatings with surface roughness of high aspect ratio producing the so-call secondary emission suppression effect appear as the selected strategy. In this work a detailed study of the SEY of these technological coatings and also the experimental deposition methods (PVD and electrochemical) are presented. The coating-design approach selected for new low SEY coatings include rough metals (Ag, Au, Al), rough alloys (NEG), particulated and magnetized surfaces, and also graphene like coatings. It was found that surface roughness also mitigate the SEY deterioration due to aging processes.Comment: 4 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Italy; CERN Yellow Report CERN-2013-002, pp.153-15

    Genomic lineages of Rhizobium etli revealed by the extent of nucleotide polymorphisms and low recombination

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    <p>Abstract</p> <p>Background</p> <p>Most of the DNA variations found in bacterial species are in the form of single nucleotide polymorphisms (SNPs), but there is some debate regarding how much of this variation comes from mutation versus recombination. The nitrogen-fixing symbiotic bacteria <it>Rhizobium etli </it>is highly variable in both genomic structure and gene content. However, no previous report has provided a detailed genomic analysis of this variation at nucleotide level or the role of recombination in generating diversity in this bacterium. Here, we compared draft genomic sequences versus complete genomic sequences to obtain reliable measures of genetic diversity and then estimated the role of recombination in the generation of genomic diversity among <it>Rhizobium etli</it>.</p> <p>Results</p> <p>We identified high levels of DNA polymorphism in <it>R. etli</it>, and found that there was an average divergence of 4% to 6% among the tested strain pairs. DNA recombination events were estimated to affect 3% to 10% of the genomic sample analyzed. In most instances, the nucleotide diversity (π) was greater in DNA segments with recombinant events than in non-recombinant segments. However, this degree of recombination was not sufficiently large to disrupt the congruence of the phylogenetic trees, and further evaluation of recombination in strains quartets indicated that the recombination levels in this species are proportionally low.</p> <p>Conclusion</p> <p>Our data suggest that <it>R. etli </it>is a species composed of separated lineages with low homologous recombination among the strains. Horizontal gene transfer, particularly via the symbiotic plasmid characteristic of this species, seems to play an important role in diversity but the lineages maintain their evolutionary cohesiveness.</p

    Electrochemical oxidation of meglumine in a pharmaceutical formulation using a nanocomposite anode

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    The electrocatalytic oxidation of meglumine and gadoterate meglumine (Gd-DOTA) on a TiO2-Ni(SO4)0.3(OH)1.4 composite anode was investigated in alkaline medium (5 M KOH) using cyclic voltammetry and chronoamperometry. The composite was prepared by hydrothermal method and the morphology and structure of the produced nanoparticles were studied by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, atomic force microscopy, BET surface area analysis and Fourier transform infrared spectroscopy. The characterization revealed the formation of Ni(SO4)0.3(OH)1.4 nanobelts dispersed on TiO2 nanoaggregates. The composite was coated onto a porous graphite rod, showing good adherence without requiring any binder (according to their anodic and cathodic charges). The supported composite was electrocatalytic, allowing the oxidation of meglumine, either as pure reagent or contained in gadoterate meglumine solutions. Electrochemical methods allowed determining the kinetic parameters, such as the electron transfer coefficient α, the total number of electrons n and the standard heterogeneous rate constant k0 for the reaction of meglumine. The chronoamperometric tests informed about the good stability of the composite anode upon meglumine oxidation at +0.6 V for 10 h. The electrochemical oxidation of meglumine in a commercial pharmaceutical formulation (Dotarem®) was corroborated via ultra-high performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry

    Reconstruction of the seasonal cycle of air–sea CO2 fluxes in the Strait of Gibraltar

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    The present study reports and discusses water surface fCO2 measurements from 36 cruises in the Strait of Gibraltar made over an eleven-year period (1997 to 2009). Underway measurements of sea surface CO2 fugacity (fCO2sw), sea surface temperature (SST) and sea surface salinity (SSS) compiled during the cruises were analysed and integrated into a single database which provided the resolution/sensitivity required for an examination of the seasonal variability of the fCO2sw; these data allowed the reconstruction of the climatological seasonal cycle for the year 2005. The seasonal cycle of both SST and SSS was found to be within the range of the thermohaline signature of the North Atlantic Surface Water, which is the main water mass that flows into the Mediterranean Sea through the Strait of Gibraltar at the surface. The seasonal distribution of fCO22005 was characterised by a monthly minimum value of 334 ± 12 μatm in May, followed by a gradual increase to a maximum of 385 μatm during late summer, due to the warming of surface waters. The spatial variability of fCO2sw observed in the area also indicated that superimposed phenomena, occurring at scales other than seasonal, could affect the dissolved CO2 distribution. In particular, intense vertical mixing processes generated by internal waves in this region may have an impact on the surface fCO2sw on a tidal scale. Seasonal CO2 cycle dynamics indicated that the surface waters of the Strait of Gibraltar acted as an atmospheric CO2 source during summer and autumn and a CO2 sink during winter and spring. When these sink/source strengths are integrated on an annual basis, the Strait of Gibraltar was close to equilibrium with atmospheric CO2, resulting in a neutral atmosphere-ocean exchange (− 0.06 ± 0.12 mol C m− 2 yr− 1).Funding for this work was provided by the CARBOOCEAN IP of the European Commission (511176GOCE) and by the Spanish Ministry of Education and Sciences through the Projects CAIBEX (CTM2007-66408) and (CTM2006-26206-E/MAR). Author Mercedes de la Paz acknowledges the financial support of the CSIC postdoctoral program JAE-Doc.Peer reviewe

    SOBREPESO EN EL LACTANTE DEL ÁREA METROPOLITANA DE MONTERREY, N.L., MEXICO

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    La etapa Lactante es una alternativa de abordaje en la lucha contra la obesidad. Se ha demostrado que existe una relación entre el exceso de peso en ésta etapa, con las principales problemas de salud pública; con base en lo anterior, es necesario buscar factores modificables en el comportamiento de los encargados del cuidado del infante y del equipo de salud para crear conductas que propicien el adecuado desarrollo del individuo. El objetivo de éste estudio es determinar la prevalencia del exceso de peso en lactantes del área metropolitana de Monterrey, a partir de usuarios del programa de atención del niño sano del IMSS, provenientes de seis unidades de medicina familiar. Se estudiaron 400 lactantes a través de la medición de peso y talla, para clasificarlos mediante las tablas diagnósticas nutricionales de la NCHS-CDC/OMS. Se obtuvo una prevalencia del exceso de peso de los lactantes estudiados equivalente al 43.23%. Mostrando que el exceso de peso representa un problema de salud pública creciente en México, el cual requiere el replanteamiento de los programas preventivos en éste sector demográfico, buscando aquellos niños que están adquiriendo patrones patológicos de comportamiento en su ingesta alimentaria. AbstractThe infant stage is an alternative in boarding the struggle against obesity. There has been demonstrated that a relation exists between overweight in this period with the current issues of public health. Due to this, it is necessary to search for adjustable factors in the carers and health team, in order to create appropriate behaviour that propitiates suiable development of the individual. The objective in this study was to determine the prevalence of overweight in Monterrey’s metropolitan area infants who assist the healthy child program from six primary health care units of the Mexican Institute of Social Security. There were studied 400 children under a year of age, to whom they there was realized measurement of weight and height, qualifying by means of the diagnostic nutritional tables of the NCHS-CDC/OMS. The results of this study show that the prevalence rates of excess body weight in infants under a year old in Monterrey’s Metropolitan area are 43.23%. There is a clear that excess body weight represents a problem of public health in México, which needs the rethinking of the preventive programs in this one population sector, in search of those children that are acquiring pathological bosses of behavior in food ingestionPalabras Clave: Lactante, prevalencia, exceso de peso, sobrepeso, obesidad, niños menores de un año

    FTO gene: Historic background and its relationship with chronic-degenerative diseases

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    Indexación: Scopus; Latindex.Alteraciones en el desarrollo de la atención y la organización conductual pueden configurar cuadros clínicos como el trastorno déficit de atención (TDA) que puede estar acompañado o no de hiperactividad (TDAH), este último parece tener una relación directa con otros diagnósticos de tipo endocrino como la obesidad. El objetivo del estudio es analizar la relación que existe entre el TDAH y la obesidad. Es por ello que se realiza una revisión sistemática de estudios científicos revelando relaciones y diferencias entre ambos trastornos desde una mirada fisiológica, cognoscitiva y comportamental. Se concluye que la relación entre el TDAH y la obesidad se da por factores genéticos, por variaciones dopaminérgicas, cambios en patrones de sueño, desajustes emocionales y por alteraciones en la regulación de la conducta; igualmente influyen factores sociales relacionados con el cuidado en el embarazo y la alimentación de las mujeres antes y durante la gestación.http://www.revhipertension.com/rlh_2_2018/5_fto_gene.pd

    HEMOGLOBINA GLUCOSILADA: PRUEBA DE LABORATORIO NECESARIA PARA EL CONTROL METABOLICO DE PACIENTES MEXICANOS CON DIABETES MELLITUS TIPO 2.

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    Además de la determinación de glucosa en sangre en ayunas (FBG), la prueba de hemoglobinaglucosilada (HbA1c) es un indicador que evalúa el grado de control metabólico de todo pacientecon diabetes mellitus tipo 2. Aunque ambas pruebas se determinan rutinariamente en muchospaíses en el mundo, para el buen control metabólico del paciente diabético, en las instituciones desalud en México solo se basan en la prueba de FBG. Conocer si los pacientes con diabetes queacudían al Hospital No. 25, IMSS en Monterrey para su control clínico (después de una evaluaciónfísica basada solamente en la prueba de FBG), estuvieron bajo un buen o mal control metabólico.Se llevo a cabo un estudio de serie de casos en el cual se midieron las concentraciones de FBG yde HbA1c en 93 pacientes diabéticos bajo tratamiento (46 mujeres y 47 hombres, con un promediode edad de 54 años) que acudían a la consulta externa del Hospital No. 25. Para evaluar el nivelde control metabólico se usaron los criterios de la Asociación Americana de Diabetes (ADA) (lacual recomienda que los niveles de HbA1c deben ser mantenidos &lt; 7.0%) y el criterio Europeo(que recomienda que los niveles de HbA1c deben ser mantenidos &lt; 7.6%). Las determinaciones deFBG se realizaron en el Hospital No. 25 y las de HbA1c en el Centro de Investigación Biomédicadel Noreste (CIBIN). De acuerdo a la prueba de FBG, los médicos clínicos detectaron que el 52%de los pacientes tuvieron cifras 140 mg/dl (mal control metabólico). Por otro lado, utilizando laprueba de HbA1c, los 93 pacientes (100%) registraron niveles &gt; a 8.0%. La prueba de HbA1cmostró que todos los pacientes tuvieron un mal control metabólico. Por lo tanto, es prioritario quelas autoridades implementen rutinariamente la prueba de HbAc1 en las instituciones de salud deMéxico y especialmente en Nuevo León dado que este Estado posee la mayor tasa de mortalidadpor diabetes (45%) a nivel nacional.AbstractGlycosylated hemoglobin (HbA1c) is a blood test that gives an estimate of the average blood sugar(glucose) for the previous three months. The fasting blood glucose (FBG) and HbA1cdeterminations give a well idea about the metabolic control of the diabetics. Both tests aredetermined routinely in many countries but into the Mexican Institutes of Health only the FBG test iscarried out for this purpose. The aim of this study was to know if non-insulin-dependent diabeticmellitus (NIDDM) outpatients attending in a clinical hospital of the IMSS after the physicianevaluation based only on the FBG test were under a good or bad metabolic control. At the sametime, we carried out the HbA1c test independently of the physician evaluation in order to know if theNIDDM patients were well evaluated. A serial case study was undertaken in which concentrations ofFBG and HbA1c were measured in 93 diabetics (under treatment) at the outpatient clinic of theIMSS in Monterrey, Mexico. A structured, self-administrated questionnaire was used to obtain dataon age, gender, duration of diabetes, a recent history of polydipsia, polyuria and polyphagia, height,weight, blood pressure, treatment kind, and BMI. The American Diabetic Association (ADA)(currently recommends that the HbA1c be maintained under 7.0%) and the European criteria(currently recommends that the HbA1c be maintained under 7.6%) were used to evaluate the levelof metabolic control. The 93 patients had HbA1C levels higher than 8.0% and FBG levels between63 and 300 mg/dl. According to ADA criteria and European criteria all the patients were out of goodmetabolic control. These points towards the HbA1c and FBG confirm the doubts about theusefulness of FBG values as a tool for assessing metabolic control. These results suggest a lowlevel in the practice of monitoring indicators in NIDDM. We suggest that the HbA1c test must betaken in account by the Mexican Institutes of Health to improve a better metabolic control in theirdiabetic patients.Palabras Clave: Diabetes, Tipo 2, Hemoglobina glucosilada, Diabetes, Type 2, Glycosylated hemoglobi

    Noncollinear magnetic ordering in small Chromium Clusters

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    We investigate noncollinear effects in antiferromagnetically coupled clusters using the general, rotationally invariant form of local spin-density theory. The coupling to the electronic degrees of freedom is treated with relativistic non-local pseudopotentials and the ionic structure is optimized by Monte-Carlo techniques. We find that small chromium clusters (N \le 13) strongly favor noncollinear configurations of their local magnetic moments due to frustration. This effect is associated with a significantly lower total magnetization of the noncollinear ground states, ameliorating the disagreement between Stern-Gerlach measurements and previous collinear calculations for Cr_{12} and Cr_{13}. Our results further suggest that the trend to noncollinear configurations might be a feature common to most antiferromagnetic clusters.Comment: 9 pages, RevTeX plus .eps/.ps figure

    Consensus document on allergic conjunctivitis (DECA)

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    Allergic conjunctivitis (AC) is an inflammatory disease of the conjunctiva caused mainly by an IgE-mediated mechanism. It is the most common type of ocular allergy. Despite being the most benign form of conjunctivitis, AC has a considerable effect on patient quality of life, reduces work productivity, and increases health care costs. No consensus has been reached on its classification, diagnosis, or treatment. Consequently, the literature provides little information on its natural history, epidemiological data are scarce, and it is often difficult to ascertain its true morbidity. The main objective of the Consensus Document on Allergic Conjunctivitis (Documento dE Consenso sobre Conjuntivitis Alérgica [DECA]), which was drafted by an expert panel from the Spanish Society of Allergology and Spanish Society of Ophthalmology, was to reach agreement on basic criteria that could prove useful for both specialists and primary care physicians and facilitate the diagnosis, classification, and treatment of AC. This document is the first of its kind to describe and analyze aspects of AC that could make it possible to control symptoms
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