Interstellar Comet 2I/Borisov exhibits a structure similar to native Solar System comets

We processed images taken with the Hubble Space Telescope (HST) to investigate any morphological features in the inner coma suggestive of a peculiar activity on the nucleus of the interstellar comet 2I/Borisov. The coma shows an evident elongation, in the position angle (PA) ~0-180d direction, which appears related to the presence of a jet originating from a single active source on the nucleus. A counterpart of this jet directed towards PA ~10d was detected through analysis of the changes of the inner coma morphology on HST images taken in different dates and processed with different filters. These findings indicate that the nucleus is probably rotating with a spin axis projected near the plane of the sky and oriented at PA ~100d-280d, and that the active source is lying in a near-equatorial position. Subsequent observations of HST allowed us to determine the direction of the spin axis at RA=17h20m+/-15d and Dec = -35d+\-10d.Comment: 5 pages, 6 figures (low resolution). Full-resolution figures and bonus material at this url https://web.oapd.inaf.it/bedin/files/PAPERs_eMATERIALs/BORISOV_comet/ Accepted for publication in MNRAS Letters on 2020 April 1st (not a joke ;

Cambios estacionales de la densidad de peces en una laguna del valle aluvial del rio Parana (Argentina)

En aval du confluent du Parana et du Paraguay, les nombreuses espèces de poissons présentes (dont beaucoup d'intérêt commercial) accomplissent des migrations complexes, latérales et longitudinales, encore inexpliquées. La structure et la densité des communautés de poissons sont fonction, pour chaque endroit, de la période de l'année. Ces variations ont été relevées dans une mare permanente de 274,5 ha dans la zone centrale de la plaine d'inondation (31°42'S; 60°37'W), et reliées à la température et au niveau de l'eau. Des estimations mensuelles de densité ont été faites entre janvier 1982 et janvier 1983 par écho-sondage, ainsi que par des pêches expérimentales utilisant les mêmes filets maillants que ceux des pêcheurs locaux. La prise moyenne a été de 21,5 kg par jour pour 100 m2 de file

SynaptoPAC, an optogenetic tool for induction of presynaptic plasticity

Optogenetic manipulations have transformed neuroscience in recent years. While sophisticated tools now exist for controlling the firing patterns of neurons, it remains challenging to optogenetically define the plasticity state of individual synapses. A variety of synapses in the mammalian brain express presynaptic long-term potentiation (LTP) upon elevation of presynaptic cyclic adenosine monophosphate (cAMP), but the molecular expression mechanisms as well as the impact of presynaptic LTP on network activity and behavior are not fully understood. In order to establish optogenetic control of presynaptic cAMP levels and thereby presynaptic potentiation, we developed synaptoPAC, a presynaptically targeted version of the photoactivated adenylyl cyclase bPAC. In cultures of hippocampal granule cells, activation of synaptoPAC with blue light increases action potential-evoked transmission, an effect not seen in hippocampal cultures of non-granule cells. In acute brain slices, synaptoPAC activation immediately triggers a strong presynaptic potentiation at mossy fiber terminals in CA3, but not at Schaffer collateral synapse in CA1. Following light-triggered potentiation, mossy fiber transmission decreases within 20 minutes, but remains enhanced still after 30 min. Optogenetic potentiation alters the short-term plasticity dynamics of release, reminiscent of presynaptic LTP. SynaptoPAC is the first optogenetic tool that allows acute light-controlled potentiation of transmitter release at specific synapses of the brain, and will enable to investigate the role of presynaptic potentiation in network function and the animal’s behavior in an unprecedented manner. SIGNIFICANCE STATEMENT: SynaptoPAC is a novel optogenetic tool that allows increasing synaptic transmission by light-controlled induction of presynaptic plasticity

Reply to: "Pre-retrieval reperfusion decreases cancer recurrence after rat ischemic liver graft transplantation"

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Aquivion® PFSA-based spray-freeze dried composite materials with SiO2 and TiO2 as hybrid catalysts for the gas phase dehydration of ethanol to ethylene in mild conditions

Aquivion PFSA resin, a perfluorinated ion-exchange polymer, has been used as a heterogeneous strong acid catalyst for a range of reactions; however, the activity of this material is limited due to the extremely low surface area of the polymer. In this paper we described the one-step synthesis of Aquivion® PFSA-based hybrid materials using heterocoagulation and spray-freeze-drying of sols containing the precursor of the active phases. The intimated encapsulation of different nano-oxides, such as TiO2 and SiO2 in the superacid resin matrix was easily obtained using this technique and compared with similar catalysts prepared by the impregnation conventional route. The approach led to the preparation of porous micro-granules characterised by a high homogeneity in the phase distribution and high surface area. The prepared materials were active and selective for the gas phase dehydration of ethanol to ethylene in mild conditions. The increase of the porosity improved the activity of the composites, compared to the pure Aquivion® PFSA, and allowed to reduce the amount of the superacid resin. Moreover, the type of encapsulated oxide, TiO2 or SiO2, modified the improved performance of the catalysts, having TiO2 the higher efficiency for ethanol conversion and selectivity in ethylene at very low temperature

Biomaterial compuesto de titanio-hidroxiapatita

Fil: Oldani, C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Fil: Grinschpun, L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Fil: Cormin, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Fil: Schneiter, M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Fil: Salvatierra, N. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Los implantes no cementados requieren el menor tiempo de osteointegración ya que el mismo hueso será su anclaje. Por lo tanto, esta aplicación requiere un material con bioactividad superficial y una estructura porosa importante. Este artículo presenta un compuesto a base de titanio, reforzado con partículas de hidroxiapatita producido mediante técnicas de metalurgia de polvos. Las materias primas fueron mezclas de polvos de hidruro de titanio e hidroxiapatita natural (20% en peso), obtenida a partir de hueso bovino, prensados a 490 MPa en un molde rígido y sinterizados a 1200 º C en vacío y a temperaturas en el rango de 600 a 1000 º C en argón. Las muestras sinterizadas a 1200 º C muestran una variación en volumen (dilatación) debido a una reacción entre los componentes del compuesto. Estas reacciones no aparecen a temperaturas bajas (600 y 800 º C), pero estas muestras exhiben cierta porosidad debido a la escasa sinterización. Los compactos se caracterizaron por metalografía y mediante pruebas biológicas de citotoxicidad. Los mejores resultados metalográficos se obtienen en las muestras sinterizadas a 800 ºC, la que no es citotóxica.Fil: Oldani, C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Fil: Grinschpun, L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Fil: Cormin, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Fil: Schneiter, M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Fil: Salvatierra, N. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Materiales; Argentina.Ingeniería de los Materiale

Sinterizado de viruta de aleación AZ91D

Fil: Milne, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Grinschpun, L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Oldani, C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Prudencio, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Schneiter, M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.La viruta proveniente de los procesos de mecanizado de autopartes para la industria automotriz, fabricadas con aleaciones de magnesio AZ91D, presenta un problema de contaminación ambiental debido a los aceites refrigerantes adheridos a la viruta. El magnesio y sus aleaciones además, está declarado como material de alto riesgo debido a su alta inflamabilidad, dificultando su almacenamiento para procesos posteriores. En este trabajo proponemos un reprocesado de la viruta mediante técnicas de pulvimetalurgia, buscando la obtención de un material con características similares a la aleación de origen. Los ensayos mecánicos realizados a los materiales obtenidos, mostraron que los mejores resultado son obtenidos para temperaturas de sinterizado en fase solido + liquido. A esta temperatura se produciría un cambio volumétrico de las partículas de polvo de la aleación que facilita la rotura de la capa de óxido que cubre a las mismas y que de otra manera, impide o dificulta la unión partícula--partícula. Las muestras obtenidas fueron caracterizadas metalográfica y mecánicamente, determinando la resistencia a la compresión del material. Los tratamientos de sinterizado se realizaron a temperaturas de 500, 600 y 650ºC, variando los tiempos de permanencia a las distintas temperaturas entre 1 y 4 horas. Se alcanzaron valores de resistencia mecánica de 115,7 MPa para las muestras sinterizadas a 600ºC durante una hora, valor cercano al 30% de los valores de la aleación original (400 MPa) y un 50% en relación a la aleación refundida (325 MPa). La caracterización metalográfica muestra que el sinterizado a las menores temperaturas utilizadas en este trabajo, presenta un alto grado de porosidad el cual se traduce en pobres propiedades mecánicas.Fil: Milne, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Grinschpun, L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Oldani, C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Prudencio, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Schneiter, M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Otras Ingeniería de los Materiale

Exploring characteristics associated with first benzodiazepine prescription in patients with affective disorders and related diagnoses

Objective In patients with affective disorders, benzodiazepines (BZDs) are frequently administered at the onset, sometimes inappropriately. We sought to identify clinical variables associated with first BZD prescription in a large sample of patients with affective disorders. Methods Four hundred sixty patients with mood or anxiety disorders attending different psychiatric services were assessed comparing those who received BZD as first treatment (BZD w/) and those who did not (BZD w/o). Results More than one third (35.7%) of the total sample had received BZDs as first prescription. In relation to mood disorders, BZD w/ subjects more frequently (a) had not a psychiatrist as first therapist, (b) had anxious symptoms at onset, (c) had adjustment disorder as first diagnosis, (d) were treated as outpatients. In relation to specific diagnoses, (a) personal decision of treatment for major depressive disorder, (b) outpatient status for bipolar disorder and (c) longer duration of untreated illness for adjustment disorder were more frequently associated with first BZD prescription. For anxiety disorders, the presence of stressful life events and the diagnoses of panic disorder or specific phobias were more frequently observed in BZD w/ patients. Conclusion Patients with affective disorders frequently received BZDs as first prescription with significant differences between and within mood and anxiety disorders

SynaptoPAC, an optogenetic tool for induction of presynaptic plasticity

Optogenetic manipulations have transformed neuroscience in recent years. While sophisticated tools now exist for controlling the firing patterns of neurons, it remains challenging to optogenetically define the plasticity state of individual synapses. A variety of synapses in the mammalian brain express presynaptic long-term potentiation (LTP) upon elevation of presynaptic cyclic adenosine monophosphate (cAMP), but the molecular expression mechanisms as well as the impact of presynaptic LTP on network activity and behavior are not fully understood. In order to establish optogenetic control of presynaptic cAMP levels and thereby presynaptic potentiation, we developed synaptoPAC, a presynaptically targeted version of the photoactivated adenylyl cyclase bPAC. In cultures of hippocampal granule cells of Wistar rats, activation of synaptoPAC with blue light increased action potential-evoked transmission, an effect not seen in hippocampal cultures of non-granule cells. In acute brain slices of C57BL/6N mice, synaptoPAC activation immediately triggered a strong presynaptic potentiation at mossy fiber synapses in CA3, but not at Schaffer collateral synapses in CA1. Following light-triggered potentiation, mossy fiber transmission decreased within 20 minutes, but remained enhanced still after 30 min. The optogenetic potentiation altered the short-term plasticity dynamics of release, reminiscent of presynaptic LTP. Our work establishes synaptoPAC as an optogenetic tool that enables acute light-controlled potentiation of transmitter release at specific synapses in the brain, facilitating studies of the role of presynaptic potentiation in network function and animal behavior in an unprecedented manner. SIGNIFICANCE STATEMENT: SynaptoPAC is a novel optogenetic tool that allows increasing synaptic transmission by light-controlled induction of presynaptic plasticity

Novel strategies to deliver melatonin (in SLN and as cryo-laser therapy) to prostate cancer cells in vivo

Background. Melatonin, synthesized in the pineal gland, modulates malignant cell proliferation via MT1 receptor or dihydrotestosterone-induced calcium influx attenuation. It has also important antioxidant and antiangiogenic properties. Solid-lipid nanoparticles (SLN) is a technology to target drugs against a specific organ, with control of the pharmacokinetics and optimization of their uptake into cancer cells. Cryopass laser therapy consists in the topical application of a frozen drug emulsion followed by a laser scan of the area to give the energy to penetrate the cutaneous barrier and deliver the active principle to the target area. Aim of the study and Methods The aim was to add knowledge on the anticancer action of melatonin with concern to prostate. We used a model of nude mice xenograft of human LNCaP prostate cancer cells and compared the response of the xenografts using up-to-date techniques and different routes to deliver the drug to cancer cells: (a) i.p. as saline; (b) i.p. in SLN; (c) by cryolaser as saline and (d) included in SLN.. Results. Melatonin administered both by i.p. or topically by cryolaser, only 50% of the xenografts resulted in the tumour growth, vs 75% in the control groups. Tumour growth curves showed a similar trend in both groups, but with a marked delay with respect to controls. The mean weight of the tumours collected 45 days after the xenograft was lower in melatonin-treated mice with respect to saline-treated controls (p<0.05). SLN-melatonin did not produce the same inhibition, but histological analysis revealed a different tumour composition. Studies on how the molecular response fits into the observed phenotype are in progress. Conclusions. The results obtained could be the basis for the introduction of this natural molecule as adjuvant active component in therapeutic strategies for the treatment of malignant prostate cancer in humans, and for prevention of cancer relapses