2,657 research outputs found

    Surface Waves and Forced Oscillations in QHE Planar Samples

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    Dispersion relations and polarizations for surface waves in infinite planar samples in the QHE regime are explicitly determined in the small wavevector limit in which the dielectric tensor can be considered as local. The wavelength and frequency regions of applicability of the results extends to the infrared region for typical experimental conditions. Then, standard samples with millimetric sizes seem to be able to support such excitations. Forced oscillations are also determined which should be generated in the 2DEG by external electromagnetic sources. They show an almost frequency independent wavevelength which decreases with the magnetic field. A qualitative model based in these solutions is also presented to describe a recently found new class of resonances appearing near the edge of a 2DEG in the QHE regime.Comment: latex file, 18 pages, 3 figures, spelling correcte

    When the Earth trembles in the americas: the experience of haiti and chile 2010.

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    The response of the nephrological community to the Haiti and Chile earthquakes which occurred in the first months of 2010 is described. In Haiti, renal support was organized by the Renal Disaster Relief Task Force (RDRTF) of the International Society of Nephrology (ISN) in close collaboration with Médecins Sans Frontières (MSF), and covered both patients with acute kidney injury (AKI) and patients with chronic kidney disease (CKD). The majority of AKI patients (19/27) suffered from crush syndrome and recovered their kidney function. The remaining 8 patients with AKI showed acute-to-chronic renal failure with very low recovery rates. The intervention of the RDRTF-ISN involved 25 volunteers of 9 nationalities, lasted exactly 2 months, and was characterized by major organizational difficulties and problems to create awareness among other rescue teams regarding the availability of dialysis possibilities. Part of the Haitian patients with AKI reached the Dominican Republic (DR) and received their therapy there. The nephrological community in the DR was able to cope with this extra patient load. In both Haiti and the DR, dialysis treatment was able to be prevented in at least 40 patients by screening and adequate fluid administration. Since laboratory facilities were destroyed in Port-au-Prince and were thus lacking during the first weeks of the intervention, the use from the very beginning on of a point-of-care device (i-STAT®) was very efficient for the detection of aberrant kidney function and electrolyte parameters. In Chile, nephrological problems were essentially related to difficulties delivering dialysis treatment to CKD patients, due to the damage to several units. This necessitated the reallocation of patients and the adaptation of their schedules. The problems could be handled by the local nephrologists. These observations illustrate that local and international preparedness might be life-saving if renal problems occur in earthquake circumstances

    Mesenchymal Stem Cell functionalization for enhanced therapeutic applications

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    To date, the therapeutic efficacy of human mesenchymal stem cells (hMSCs) has been investigated in various clinical trials with moderate or in some cases inconsistent results. The still elusive reproducibility relates in part with constitutive differences in the cell preparation, translated into variable “cell potencies”. Other factors include poor cell homing and survival, and age/disease-associated host tissue impairment. It is well accepted that within in vivo niches MSCs exist as heterogeneous cell populations with different stemness propensities and supportive functions. Phenotype-based MSC purification of homogeneous subsets can result in cell populations with distinct biological functions. In addition, preclinical studies have shown that MSC functionalization in vitro, via cell priming, can boost their immunomodulatory, trophic and reparative capacities in vivo. Therefore, in the present review we discuss how phenotype-based MSC purification and MSC priming technologies can contribute to an improved MSC-based product for safer and more effective therapeutic applications

    Qualidade de silagens de híbridos de sorgo (Sorghum bicolor (L.) Moench) de portes baixo, médio e alto com diferentes proporções de colmo+folhas/panicula. 2. Avaliação do valor nutritivo.

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    O objetivo deste experimento foi avaliar a qualidade nutricional de silagens de sorgo de portes alto, médio e baixo, com diferentes combinações de colmo+folhas/panícula (100:00, 80:20, 60:40, 40:60, 20:80 e 00:100), por meio de análises laboratoriais. A planta inteira foi utilizada como controle. Os híbridos foram cultivados e ensilados aos 104 dias de idade em silos de laboratório de PVC, com 10 cm de diâmetro e 40 cm de comprimento (três repetições por tratamento). Os silos foram abertos aos 56 dias após a ensilagem. Os teores de proteína bruta e a digestibilidade in vitro da matéria seca, dos fenóis totais e dos constituintes da parede celular pelo método seqüencial foram determinados. As diferenças foram verificadas por intermédio do teste SNK para fenóis totais, sendo realizada análise de regressão para os demais resultados. Os valores de carboidratos solúveis do material original foram baixos para a maioria dos tratamentos, porém isto não prejudicou a fermentação, pois houve utilização de carboidratos adicionais, como hemicelulose e celulose, durante a ensilagem, sendo a queda destes maior na panícula e em colmo+folhas, respectivamente. Os valores de fenóis totais aumentaram com a ensilagem, apesar de não ter ocorrido redução concomitante na DIVMS. A inclusão de panícula na planta reduziu os teores dos constituintes da parede celular e aumentou os valores de DIVM, indicando que uma planta de sorgo para produzir silagem de boa qualidade deve ter, no mínimo, 40% de panícula e baixos teores de lignina, fenóis totais e constituintes da fibra

    Autoantibody levels are associated with acute kidney injury, anemia and post-discharge morbidity and mortality in Ugandan children with severe malaria

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    Autoantibodies targeting host antigens contribute to autoimmune disorders, frequently occur during and after infections and have been proposed to contribute to malaria-induced anemia. We measured anti-phosphatidylserine (PS) and anti-DNA antibody levels in 382 Ugandan children prospectively recruited in a study of severe malaria (SM). High antibody levels were defined as antibody levels greater than the mean plus 3 standard deviations of community children (CC). We observed increases in median levels of anti-PS and anti-DNA antibodies in children with SM compared to CC (p < 0.0001 for both). Children with severe malarial anemia were more likely to have high anti-PS antibodies than children with cerebral malaria (16.4% vs. 7.4%), p = 0.02. Increases in anti-PS and anti-DNA antibodies were associated with decreased hemoglobin (p < 0.05). A one-unit increase in anti-DNA antibodies was associated with a 2.99 (95% CI, 1.68, 5.31) increase odds of acute kidney injury (AKI) (p < 0.0001). Elevated anti-PS and anti-DNA antibodies were associated with post-discharge mortality (p = 0.031 and p = 0.042, respectively). Children with high anti-PS antibodies were more likely to have multiple hospital readmissions compared to children with normal anti-PS antibody levels (p < 0.05). SM is associated with increased autoantibodies against PS and DNA. Autoantibodies were associated with anemia, AKI, post-discharge mortality, and hospital readmission

    Campbell Penetration Depth of a Superconductor in the Critical State

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    The magnetic penetration depth λ(T,H,j)\lambda(T,H,j) was measured in the presence of a slowly relaxing supercurrent, jj. In single crystal Bi2Sr2CaCu2O8\mathrm{Bi_2Sr_2CaCu_2O_8} below approximately 25 K, λ(T,H,j)\lambda(T,H,j) is strongly hysteretic. We propose that the irreversibility arises from a shift of the vortex position within its pinning well as jj changes. The Campbell length depends upon the ratio j/jcj/j_{c} where jcj_{c} is the critical current defined through the Labusch parameter. Similar effects were observed in other cuprates and in an organic superconductor

    Quantum manipulation via atomic-scale magnetoelectric effects

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    Magnetoelectric effects at the atomic scale are demonstrated to afford unique functionality. This is shown explicitly for a quantum corral defined by a wall of magnetic atoms deposited on a metal surface where spin-orbit coupling is observable. We show these magnetoelectric effects allow one to control the properties of systems placed inside the corral as well as their electronic signatures; they provide alternative tools for probing electronic properties at the atomic scale

    Comparative analysis of the fecal microbiota from different species of domesticated and wild suids

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    This study was supported by the Ministry of Economy and Competitiveness (MINECO) from the Spanish Government (grant number AGL2016-78160-C2-1-R). The authors are also grateful to the Centres de Recerca de Catalunya (CERCA) Programme and Global Alliance for Research on African swine fever (GARA). The authors thank Frederic Paboeuf and Audrey Fougeroux for providing SPF and domestic pig samples.Most of the microorganisms living in a symbiotic relationship in different animal body sites (microbiota) reside in the gastrointestinal tract (GIT). Several studies have shown that the microbiota is involved in host susceptibilities to pathogens. The fecal microbiota of domestic and wild suids was analyzed. Bacterial communities were determined from feces obtained from domestic pigs (Sus scrofa) raised under different conditions: specific-pathogen-free (SPF) pigs and domestic pigs from the same bred, and indigenous domestic pigs from a backyard farm in Kenya. Secondly, the fecal microbiota composition of the African swine fever (ASF) resistant warthogs (Phacochoerus africanus) from Africa and a European zoo was determined. African swine fever (ASF) is a devastating disease for domestic pigs. African animals showed the highest microbial diversity while the SPF pigs the lowest. Analysis of the core microbiota from warthogs (resistant to ASF) and pigs (susceptible to ASF) showed 45 shared OTUs, while 6 OTUs were exclusively present in resistant animals. These six OTUs were members of the Moraxellaceae family, Pseudomonadales order and Paludibacter, Anaeroplasma, Petrimonas, and Moraxella genera. Further characterization of these microbial communities should be performed to determine the potential involvement in ASF resistance
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