130 research outputs found

    Crecimiento y caracterización de películas delgadas de V6 O13 por Sputtering Magnetron dc

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    Se reporta el crecimiento de películas delgadas de óxido de vanadio V6 O13 en fase pura sobre substratos amorfos, por la técnica de deposición sputtering reactivo con magnetrón dc. El estudio a partir de películas delgadas de este material ha tomado mucha importancia por sus propiedades electrocrómicas y su potencial uso como interruptores ópticos. Estudios de difracción de rayos x demostraron que las películas de V6O13 están altamente orientadas en la dirección (00l) . Las películas se lograron crecer bajo una atmósfera de oxígeno y argón con presión parcial de 0.8mTorr y 5.1mTorr respectivamente, y a una temperatura de substrato de 400ºC. Las películas fueron caracterizadas por sus propiedades ópticas a partir de medidas de transmitancia en el rango de luz visible y ultravioleta, así como por sus propiedades eléctricas midiéndose el cambio de resistencia en función de la temperatura. Reportamos el comportamiento que exhiben las películas de V6 O13 en radiación de largo de onda del IR. Las medidas de transmisión se hicieron en un rango de temperatura de 4 K a 180 K, rango en el cual el material experimenta cambio de fases de metálico. El estudio topográfico se hizo con microscopio fuerza atómica (AFM). A partir de los espectros de transmitancia en el rango de luz visible y ultravioleta se estimó en 2.75eV el ancho de banda prohibida del V6 O13, resultado que está dentro del rango de valores estimado para este material.Abstract: We report the growing of thin films of pure vanadium oxide V6 O13 on amorphous substrates, using the reactive sputtering technique with dc magnetron. The study of these thin films has become relevant due to their electrocromic properties and their potential to be used as optical switches. X rays diffraction studies showed that the thin films are highly oriented in the direction. They were grown under an oxygen and argon atmosphere and with a partial pressure of 0.8 mTorr and 5.1 mTorr respectively while the temperature was kept at 400 ºC. Optical properties of the thin films were studied measuring transmission in the visible light and ultraviolet ranges. Additional, electrical measurements of the resistance as a function of the temperature were obtained. We report the behavior that this films exhibit in the IR wavelength range. The transmission data was gathered in the temperature range of 4 to 180K, values within the material experiences a phase change. The topographic study was done with atomic force microscope (AFM). From the transmission spectra in the visible Light and ultraviolet range a energy gap of 2.75 eV was determined for the films, result that is in agreement with the known values for this material

    Building a Species Conservation Strategy for the brown howler monkey (Alouatta guariba clamitans) in Argentina in the context of yellow fever outbreaks

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    El mono aullador marrón (Alouatta guariba clamitans) es endémico del Bosque Atlántico de América del Sur, con una pequeña población que se extiende en la porción norte de la provincia de Misiones en el noreste de Argentina. En el año 2012, debido a su reducida distribución geográfica, su baja densidad poblacional y al dramático impacto de los recientes brotes de Fiebre Amarilla, la especie fue categorizada en Argentina como “en peligro crítico”. En el mes de marzo de 2013 organizamos un taller internacional en Misiones con el objetivo de evaluar el estado de la población de esta especie en Argentina y llevar a cabo un análisis de las principales amenazas para su conservación. Para alcanzar estos objetivos construimos modelos de viabilidad poblacional utilizando los programas Vortex y Outbreak. Los mismos nos permitieron explorar cómo varios parámetros biológicos y demográficos de la especie, así como diversos factores relacionados al impacto de la Fiebre Amarilla, influyen sobre la probabilidad de extinción de la especie. La discusión entre los distintos especialistas y el análisis de los resultados de los modelos identificaron a la Fiebre Amarilla como la principal amenaza para la subsistencia de esta población en Argentina. El análisis de las amenazas se centró en la dinámica de los brotes de Fiebre Amarilla y la severidad de su impacto sobre la población de esta especie, lo que permitió identificar huecos en el conocimiento que permitieron priorizar objetivos y acciones a llevar a cabo para el desarrollo de una estrategia de conservación para esta especie en Argentina.The brown howler monkey (Alouatta guariba clamitans) is endemic to South America’s Atlantic Forest, with a small population extending into the northern portion of Misiones province in northeastern Argentina. In 2012, the species was classified as Critically Endangered in Argentina due to its highly restricted distribution, low population density and dramatic declines from recent Yellow Fever outbreaks. In March 2013, we organized an international workshop in Misiones to evaluate population status in Argentina and conduct a threat analysis. We developed population viability models using Vortex and Outbreak software packages. These tools allowed us to explore how several biological and demographic parameters of brown howlers, as well as factors related to Yellow Fever epidemiology, affect the probability of species extinction. The discussion among diverse specialists and analysis of model results identified Yellow Fever as the main threat to brown howler population persistence in Argentina. Our threat analysis, focused on the dynamics of Yellow Fever outbreaks and their impact on howler populations, led to the identification of gaps in knowledge that helped prioritize objectives and actions for the development of a Species Conservation Strategy in Argentina.Fil: Agostini, Ilaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Universidad Nacional de Misiones. Instituto de Biología Subtropical; Argentina. Centro de Investigaciones del Bosque Atlantico; ArgentinaFil: Holzmann, Ingrid. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Universidad Nacional de Misiones. Instituto de Biología Subtropical; Argentina. Centro de Investigaciones del Bosque Atlantico; ArgentinaFil: Di Bitetti, Mario Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Universidad Nacional de Misiones. Instituto de Biología Subtropical; Argentina. Centro de Investigaciones del Bosque Atlantico; ArgentinaFil: Oklander, Luciana Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Universidad Nacional de Misiones. Instituto de Biología Subtropical; Argentina. Centro de Investigaciones del Bosque Atlantico; ArgentinaFil: Kowalewski, Miguel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Biológica de Usos Multiples (sede Corrientes); ArgentinaFil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Cs.veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Goenaga, S.. Dirección Nacional de Instituto de Investigación. Adm.nacional de Laboratorio E Instituto de Salud "dr.c.g.malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Martínez, Mariela Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Universidad Nacional de Misiones. Instituto de Biología Subtropical; Argentina. Ministerio de Salud. Instituto Nacional de Medicina Tropical; ArgentinaFil: Moreno, Eduardo S.. Ministerio da Saude; BrasilFil: Lestani, Eduardo. Ministerio de Salud. Instituto Nacional de Medicina Tropical; ArgentinaFil: Desbiez, Arnaud L. J.. Royal Zoological Society of Scotland; Reino Unido. Conservation Breeding Specialist Group; Estados UnidosFil: Miller, Philip. Conservation Breeding Specialist Group; Estados Unido

    Effects of Invertebrate Iridescent Virus 6 in Phyllophaga vandinei and Its Potential as a Biocontrol Delivery System

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    Invertebrate iridescent virus 6 (IIV6) was determined to cause infection in Phyllophaga vandinei Smyth (Coleoptera: Scarabaeidae) through a range of modes of transmissions. This is the first evidence of IIV6 infection in P. vandinei that caused both patent and sub-lethal infections in larvae and adults. Mortality rates were determined to be ∼30% when virus inoculum was injected into larvae or adults. Adults injected with virus showed dramatically altered behavior; injected beetles were not observed feeding or mating compared with adults injected with buffer or adults that were not injected. Tissue collected from infected adults resulted in infection when injected into healthy adults, as confirmed with PCR. PCR also confirmed that frass of infected larvae and adults contained virus, and when reconstituted frass from infected individuals was injected into healthy adults or larvae they become infected. Healthy adults could be infected by coming into contact with soil or plant material that had been exposed to infected adults as much as two weeks prior to introduction of nonvirus exposed adults. Although relatively low mortality resulted when adults or larvae were injected with the virus, the demonstration of horizontal transmission, potentially through frass of infected individuals, identifies a mode of transmission that may be exploited as a potential management tool to reduce P. vandinei

    Linezolid for infective endocarditis. A structured approach based on a national database experience

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    Current data on the frequency and efficacy of linezolid (LNZ) in infective endocarditis (IE) are based on small retrospective series. We used a national database to evaluate the effectiveness of LNZ in IE. This is a retrospective study of IE patients in the Spanish GAMES database who received LNZ. We defined 3 levels of therapeutic impact: LNZ 50% of the total treatment, and > 50% of the LNZ doses prescribed in the first weeks of treatment), and LNZ ? 7 days not fulfilling the high-impact criteria (LNZ-NHI). Effectiveness of LNZ was assessed using propensity score matching and multivariate analysis of high-impact cases in comparison to patients not treated with LNZ from the GAMES database matched for age-adjusted comorbidity Charlson index, heart failure, renal failure, prosthetic and intracardiac IE device, left-sided IE, and Staphylococcus aureus. Primary outcomes were in-hospital mortality and one-year mortality. Secondary outcomes included IE complications and relapses

    Human antibodies targeting cell surface antigens overexpressed by the hormone refractory metastatic prostate cancer cells: ICAM-1 is a tumor antigen that mediates prostate cancer cell invasion

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    Transition from hormone-sensitive to hormone-refractory metastatic tumor types poses a major challenge for prostate cancer treatment. Tumor antigens that are differentially expressed during this transition are likely to play important roles in imparting prostate cancer cells with the ability to grow in a hormone-deprived environment and to metastasize to distal sites such as the bone and thus, are likely targets for therapeutic intervention. To identify those molecules and particularly cell surface antigens that accompany this transition, we studied the changes in cell surface antigenic profiles between a hormone-sensitive prostate cancer line LNCaP and its hormone-refractory derivative C4-2B, using an antibody library-based affinity proteomic approach. We selected a naïve phage antibody display library to identify human single-chain antibodies that bind specifically to C4-2B but not LNCaP. Using mass spectrometry, we identified one of the antibody-targeted antigens as the ICAM-1/CD54/human rhinovirus receptor. Recombinant IgG1 derived from this single-chain antibody binds to a neutralizing epitope of ICAM-1 and blocks C4-2B cell invasion through extracellular matrix in vitro. ICAM-1 is thus differentially expressed during the transition of the hormone-sensitive prostate cancer cell line LNCaP to its hormone-refractory derivative C4-2B, plays an important role in imparting the C4-2B line with the ability to invade, and may therefore be a target for therapeutic intervention

    Detection of the mosquito-borne flaviviruses, West Nile, Dengue, Saint Louis Encephalitis, Ilheus, Bussuquara, and Yellow Fever in free-ranging black howlers (Alouatta caraya) of Northeastern Argentina

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    Several medically important mosquito-borne flaviviruses have been detected in Argentina in recent years: Dengue (DENV), St. Louis encephalitis (SLEV), West Nile (WNV) and Yellow Fever (YFV) viruses. Evidence of Bussuquara virus (BSQV) and Ilheus virus (ILHV) activity were found, but they have not been associated with human disease. Non-human primates can act as important hosts in the natural cycle of flaviviruses and serological studies can lead to improved understanding of virus circulation dynamics and host susceptibility. From July–August 2010, we conducted serological and molecular surveys in free–ranging black howlers (Alouatta caraya) captured in northeastern Argentina. We used 90% plaque-reduction neutralization tests (PRNT90) to analyze 108 serum samples for antibodies to WNV, SLEV, YFV, DENV (serotypes 1and 3), ILHV, and BSQV. Virus genome detection was performed using generic reverse transcription (RT)-nested PCR to identify flaviviruses in 51 antibody-negative animals. Seventy animals had antibodies for one or more flaviviruses for a total antibody prevalence of 64.8% (70/108). Monotypic (13/70, 19%) and heterotypic (27/70, 39%) patterns were differentiated. Specific neutralizing antibodies against WNV, SLEV, DENV-1, DENV-3, ILHV, and BSQV were found. Unexpectedly, the highest flavivirus antibody prevalence detected was to WNV with 9 (8.33%) monotypic responses. All samples tested by (RT)-nested PCR were negative for viral genome. This is the first detection of WNV-specific antibodies in black howlers from Argentina and the first report in free-ranging non-human primates from Latin-American countries. Given that no animals had specific neutralizing antibodies to YFV, our results suggest that the study population remains susceptible to YFV. Monitoring of these agents should be strengthened to detect the establishment of sylvatic cycles of flaviviruses in America and evaluate risks to wildlife and human health.Fil: Morales, Maria Alejandra. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Fabbri, Cintia M.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Zunino, Gabriel Eduardo. Universidad Nacional de General Sarmiento. Instituto del Conurbano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kowalewski, Miguel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Biológica de Usos Múltiples (Sede Corrientes); ArgentinaFil: Luppo, Victoria C.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Enría, Delia A.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Levis, Silvana C.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; ArgentinaFil: Calderón, Gladys Ethel. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Virales Humanas; Argentin

    Phosphorylation of AMPA Receptors Is Required for Sensory Deprivation-Induced Homeostatic Synaptic Plasticity

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    Sensory experience, and the lack thereof, can alter the function of excitatory synapses in the primary sensory cortices. Recent evidence suggests that changes in sensory experience can regulate the synaptic level of Ca2+-permeable AMPA receptors (CP-AMPARs). However, the molecular mechanisms underlying such a process have not been determined. We found that binocular visual deprivation, which is a well-established in vivo model to produce multiplicative synaptic scaling in visual cortex of juvenile rodents, is accompanied by an increase in the phosphorylation of AMPAR GluR1 (or GluA1) subunit at the serine 845 (S845) site and the appearance of CP-AMPARs at synapses. To address the role of GluR1-S845 in visual deprivation-induced homeostatic synaptic plasticity, we used mice lacking key phosphorylation sites on the GluR1 subunit. We found that mice specifically lacking the GluR1-S845 site (GluR1-S845A mutants), which is a substrate of cAMP-dependent kinase (PKA), show abnormal basal excitatory synaptic transmission and lack visual deprivation-induced homeostatic synaptic plasticity. We also found evidence that increasing GluR1-S845 phosphorylation alone is not sufficient to produce normal multiplicative synaptic scaling. Our study provides concrete evidence that a GluR1 dependent mechanism, especially S845 phosphorylation, is a necessary pre-requisite step for in vivo homeostatic synaptic plasticity

    Identification of IGF1, SLC4A4, WWOX, and SFMBT1 as Hypertension Susceptibility Genes in Han Chinese with a Genome-Wide Gene-Based Association Study

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    Hypertension is a complex disorder with high prevalence rates all over the world. We conducted the first genome-wide gene-based association scan for hypertension in a Han Chinese population. By analyzing genome-wide single-nucleotide-polymorphism data of 400 matched pairs of young-onset hypertensive patients and normotensive controls genotyped with the Illumina HumanHap550-Duo BeadChip, 100 susceptibility genes for hypertension were identified and also validated with permutation tests. Seventeen of the 100 genes exhibited differential allelic and expression distributions between patient and control groups. These genes provided a good molecular signature for classifying hypertensive patients and normotensive controls. Among the 17 genes, IGF1, SLC4A4, WWOX, and SFMBT1 were not only identified by our gene-based association scan and gene expression analysis but were also replicated by a gene-based association analysis of the Hong Kong Hypertension Study. Moreover, cis-acting expression quantitative trait loci associated with the differentially expressed genes were found and linked to hypertension. IGF1, which encodes insulin-like growth factor 1, is associated with cardiovascular disorders, metabolic syndrome, decreased body weight/size, and changes of insulin levels in mice. SLC4A4, which encodes the electrogenic sodium bicarbonate cotransporter 1, is associated with decreased body weight/size and abnormal ion homeostasis in mice. WWOX, which encodes the WW domain-containing protein, is related to hypoglycemia and hyperphosphatemia. SFMBT1, which encodes the scm-like with four MBT domains protein 1, is a novel hypertension gene. GRB14, TMEM56 and KIAA1797 exhibited highly significant differential allelic and expressed distributions between hypertensive patients and normotensive controls. GRB14 was also found relevant to blood pressure in a previous genetic association study in East Asian populations. TMEM56 and KIAA1797 may be specific to Taiwanese populations, because they were not validated by the two replication studies. Identification of these genes enriches the collection of hypertension susceptibility genes, thereby shedding light on the etiology of hypertension in Han Chinese populations
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