75 research outputs found

    Water insertion and combined interstitial-vacancy oxygen conduction in the layered perovskites La1.2Sr0.8−xBaxInO4+δ

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    Layered perovskites of K2NiF4-type consist of single octahedral sheets alternating with NaCl-type layers, containing a substantial interstitial space. Based on the parent LaSrInO4+δ oxide, the series of title compounds have been prepared and investigated as possible solid electrolytes for solid-oxide fuel cells (SOFC). A charge misbalance is created by departure from the La/Sr = 1 : 1 ratio, favoring the insertion of extra oxygen atoms. The oxygen diffusion is further favored by introducing large Ba2+ ions, expanding the unit-cell size. Surprisingly, the presence of basic Ba ions drives the spontaneous insertion of water molecules in the interstitial space, as unveiled by a neutron powder diffraction (NPD) study at RT. Moreover, H2O molecules are split within the structure with protons bonded to the axial oxygens of the InO6 octahedra, and with OH units occupying the interstitial space. Electrical Conductivity measurements were made. The dc conductivity was measured under different oxygen partial pressures for both Ba-doped compounds at 600 °C and 800 °C showing mixed ionic and p-type electronic behavior at different oxygen partial pressures but with conductivities of the order of ≈10−4 (S cm−1), far below the conductivities values of the oxide electrodes used in SOFCs. To analyze the nature of the majority charge carrier, ac impedance spectroscopy (IS) was applied. In the temperature range 500-900 °C, La1.2Sr0.6Ba0.2InO4+δ oxide exhibits a conductivity improvement with respect to La1.2Sr0.8InO4+δ. Temperature-dependent NPD data show at 600 °C and 800 °C the presence of oxygen vacancies at the axial octahedral positions as well as interstitial oxygen, favoring a mixed conduction mechanism for oxide ions, which may account for the enhancement of the transport properties. The present result endorses the validity of this design procedure and supports K2NiF4-related compounds as promising candidates for solid-oxide electrolytes.Fil: Troncoso, L.. Universidad Austral de Chile; ChileFil: Arce, Mauricio Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: Fernández Díaz, M. T.. Institut Laue Langevin; FranciaFil: Mogni, Liliana Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: Alonso, J. A.. Instituto de Ciencia de Materiales de Madrid; Españ

    Case report: Gastroenterological management in a case of cardio-facio-cutaneous syndrome

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    Backgroundcardio-facio-cutaneous syndrome is a rare genetic disorder affecting less than 900 people in the world. It is mainly characterized by craniofacial, dermatologic and cardiac defects, but also gastroenterological symptoms may be present, ranging from feeding difficulties to gastroesophageal reflux and constipation.In this report we describe a case of this syndrome characterized by severe feeding and growth difficulties, with a particular focus on the management of gastroenterological complications.Case presentationthe patient was a caucasian male affected by Cardio-Facio-Cutaneous syndrome who presented feeding difficulties already a few hours after birth. These symptoms worsened in the following months and lead to a complete growth arrest and malnutrition. He was first treated with a nasogastric tube placement. Subsequently, a laparoscopic Nissen fundoplication and a laparoscopic Stamm gastrostomy were performed. The child was fed with nocturnal enteral nutrition and diurnal oral and enteral nutrition. Eventually the patient resumed feeding validly and regained adequate growth.Conclusionthis paper aims to bring to light a complex rare syndrome that infrequently comes to the attention of the pediatricians and whose diagnosis is not always straightforward. We also highlight the possible complications under a gastroenterologic point of view. Our contribution can be helpful to the pediatrician in the first diagnostic suspect of this syndrome. In particular, it is worth highlighting that -in an infant with Noonan-like features- symptoms like suction or swallowing problems, vomiting and feeding difficulties should orient towards the diagnosis of a Cardio-facio-cutaneous syndrome. It is also important to stress that its related gastroenterological issues may lead to severe growth failure and therefore the role of the gastroenterologist is key to manage supplemental feeding and to establish whether a nasogastric or gastrostomic tube placement is necessary

    Inelastic response of silicon to shock compression

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    The elastic and inelastic response of [001] oriented silicon to laser compression has been a topic of considerable discussion for well over a decade, yet there has been little progress in understanding the basic behaviour of this apparently simple material. We present experimental x-ray diffraction data showing complex elastic strain profiles in laser compressed samples on nanosecond timescales. We also present molecular dynamics and elasticity code modelling which suggests that a pressure induced phase transition is the cause of the previously reported 'anomalous' elastic waves. Moreover, this interpretation allows for measurement of the kinetic timescales for transition. This model is also discussed in the wider context of reported deformation of silicon to rapid compression in the literature

    Calendario sanitario caprino para la provincia de Neuquén

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    Las enfermedades que afectan a los caprinos perjudican la producción –tanto de carne como de fibras–, aumentan los costos de la actividad, disminuyen los ingresos y, en situaciones extremas, pueden provocar la muerte de los animales. Implementar buenas prácticas de manejo en general y aplicar un plan sanitario adecuado permite que los caprinos expresen todo su potencial productivo, disminuyendo la presencia de enfermedades y favoreciendo la supervivencia de los animales.E.E.A. Bariloche, AER San Martín de los Andes, AER Zapala, AER Chos-Malal, AER Picun LeufuFil: Martinez, Agustin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Larroza, Marcela Patricia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área Producción Animal. Grupo Sanidad Animal; ArgentinaFil: Centelles, Ivan Jesus. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Agencia de Extensión Rural Chos-Malal; ArgentinaFil: Mikuc, Juan Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Agencia de Extensión Rural Chos Malal; ArgentinaFil: Castilla, Florencia. Instituto Nacional de Tecnología Agropecuaria (INTA). Centro Regional Patagonia Norte; ArgentinaFil: Do Eyo, Maria De Las Mercedes. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área Desarrollo Rural. Grupo Gestión de la Información; ArgentinaFil: Lagorio, Paula Agustina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área Desarrollo Rural. Grupo Gestión de la Información; ArgentinaFil: Castillo, Belisario. Agente de Producción y sanidad animal de la comunidad Mapuche Huayqillan; ArgentinaFil: Albornoz Daniel. Cooperativa Paraíso del Norte Manzano Amargo; ArgentinaFil: Alberghini, Juan Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación y Desarrollo Tecnológico para la Agricultura Familiar Región Cuyo; ArgentinaFil: Mogni, Javier Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Agencia de Extensión Rural Chos-Malal; Argentin

    Language production impairments in patients with a first episode of psychosis

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    Telethon Network of Genetic Biobanks: a key service for diagnosis and research on rare diseases

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    Several examples have always illustrated how access to large numbers of biospecimens and associated data plays a pivotal role in the identification of disease genes and the development of pharmaceuticals. Hence, allowing researchers to access to significant numbers of quality samples and data, genetic biobanks are a powerful tool in basic, translational and clinical research into rare diseases. Recently demand for well-annotated and properly-preserved specimens is growing at a high rate, and is expected to grow for years to come. The best effective solution to this issue is to enhance the potentialities of well-managed biobanks by building a network.Here we report a 5-year experience of the Telethon Network of Genetic Biobanks (TNGB), a non-profit association of Italian repositories created in 2008 to form a virtually unique catalogue of biospecimens and associated data, which presently lists more than 750 rare genetic defects. The process of TNGB harmonisation has been mainly achieved through the adoption of a unique, centrally coordinated, IT infrastructure, which has enabled (i) standardisation of all the TNGB procedures and activities; (ii) creation of an updated TNGB online catalogue, based on minimal data set and controlled terminologies; (iii) sample access policy managed via a shared request control panel at web portal. TNGB has been engaged in disseminating information on its services into both scientific/biomedical - national and international - contexts, as well as associations of patients and families. Indeed, during the last 5-years national and international scientists extensively used the TNGB with different purposes resulting in more than 250 scientific publications. In addition, since its inception the TNGB is an associated member of the Biobanking and Biomolecular Resources Research Infrastructure and recently joined the EuroBioBank network. Moreover, the involvement of patients and families, leading to the formalization of various agreements between TNGB and Patients' Associations, has demonstrated how promoting Biobank services can be instrumental in gaining a critical mass of samples essential for research, as well as, raising awareness, trust and interest of the general public in Biobanks. This article focuses on some fundamental aspects of networking and demonstrates how the translational research benefits from a sustained infrastructure

    Phase Transition Lowering in Dynamically Compressed Silicon

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    Silicon, being one of the most abundant elements in nature, attracts wide-ranging scientific and technological interest. Specifically, in its elemental form, crystals of remarkable purity can be produced. One may assume that this would lead to silicon being well understood, and indeed, this is the case for many ambient properties, as well as for higher-pressure behaviour under quasi-static loading. However, despite many decades of study, a detailed understanding of the response of silicon to rapid compression—such as that experienced under shock impact—remains elusive. Here, we combine a novel free-electron laser-based X-ray diffraction geometry with laser-driven compression to elucidate the importance of shear generated during shock compression on the occurrence of phase transitions. We observe lowering of the hydrostatic phase boundary in elemental silicon, an ideal model system for investigating high-strength materials, analogous to planetary constituents. Moreover, we unambiguously determine the onset of melting above 14 GPa, previously ascribed to a solid–solid phase transition, undetectable in the now conventional shocked diffraction geometry; transitions to the liquid state are expected to be ubiquitous in all systems at sufficiently high pressures and temperatures
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