In-doped Sb nanowires grown by MOCVD for high speed phase change memories

We investigated the Phase Change Memory (PCM) capabilities of In-doped Sb nanowires (NWs) with diameters of (20-40) nm, which were self-assembled by Metalorganic Chemical Vapor Deposition (MOCVD) via the vapor-liquid-solid (VLS) mechanism. The PCM behavior of the NWs was proved, and it was shown to have relatively low reset power consumption (~ 400 μW) and fast switching capabilities with respect to standard Ge-Sb-Te based devices. In particular, reversible set and reset switches by voltage pulses as short as 25 ns were demonstrated. The obtained results are useful for understanding the effects of downscaling in PCM devices and for the exploration of innovative PCM architectures and materials. Keywords: Phase change memories, Nanowires, MOCVD, In-Sb, TEM, XR

In-doped Sb nanowires grown by MOCVD for high speed phase change memories

We investigated the Phase Change Memory (PCM) capabilities of In-doped Sb nanowires (NWs) with diameters of (20-40) nm, which were self-assembled by Metalorganic Chemical Vapor Deposition (MOCVD) via the vapor-liquid-solid (VLS) mechanism. The PCM behavior of the NWs was proved, and it was shown to have relatively low reset power consumption (~ 400 μW) and fast switching capabilities with respect to standard Ge-Sb-Te based devices. In particular, reversible set and reset switches by voltage pulses as short as 25 ns were demonstrated. The obtained results are useful for understanding the effects of downscaling in PCM devices and for the exploration of innovative PCM architectures and materials

Protective Mechanical Ventilation during General Anesthesia for Open Abdominal Surgery Improves Postoperative Pulmonary Function

BACKGROUND:: The impact of intraoperative ventilation on postoperative pulmonary complications is not defined. The authors aimed at determining the effectiveness of protective mechanical ventilation during open abdominal surgery on a modified Clinical Pulmonary Infection Score as primary outcome and postoperative pulmonary function. METHODS:: Prospective randomized, open-label, clinical trial performed in 56 patients scheduled to undergo elective open abdominal surgery lasting more than 2 h. Patients were assigned by envelopes to mechanical ventilation with tidal volume of 9 ml/kg ideal body weight and zero-positive end-expiratory pressure (standard ventilation strategy) or tidal volumes of 7 ml/kg ideal body weight, 10 cm H2O positive end-expiratory pressure, and recruitment maneuvers (protective ventilation strategy). Modified Clinical Pulmonary Infection Score, gas exchange, and pulmonary functional tests were measured preoperatively, as well as at days 1, 3, and 5 after surgery. RESULTS:: Patients ventilated protectively showed better pulmonary functional tests up to day 5, fewer alterations on chest x-ray up to day 3 and higher arterial oxygenation in air at days 1, 3, and 5 (mmHg; mean \ub1 SD): 77.1 \ub1 13.0 versus 64.9 \ub1 11.3 (P = 0.0006), 80.5 \ub1 10.1 versus 69.7 \ub1 9.3 (P = 0.0002), and 82.1 \ub1 10.7 versus 78.5 \ub1 21.7 (P = 0.44) respectively. The modified Clinical Pulmonary Infection Score was lower in the protective ventilation strategy at days 1 and 3. The percentage of patients in hospital at day 28 after surgery was not different between groups (7 vs. 15% respectively, P = 0.42). CONCLUSION:: A protective ventilation strategy during abdominal surgery lasting more than 2 h improved respiratory function and reduced the modified Clinical Pulmonary Infection Score without affecting length of hospital stay

Catastrophic NAD+ Depletion in Activated T Lymphocytes through Nampt Inhibition Reduces Demyelination and Disability in EAE

Nicotinamide phosphoribosyltransferase (Nampt) inhibitors such as FK866 are potent inhibitors of NAD+ synthesis that show promise for the treatment of different forms of cancer. Based on Nampt upregulation in activated T lymphocytes and on preliminary reports of lymphopenia in FK866 treated patients, we have investigated FK866 for its capacity to interfere with T lymphocyte function and survival. Intracellular pyridine nucleotides, ATP, mitochondrial function, viability, proliferation, activation markers and cytokine secretion were assessed in resting and in activated human T lymphocytes. In addition, we used experimental autoimmune encephalomyelitis (EAE) as a model of T-cell mediated autoimmune disease to assess FK866 efficacy in vivo. We show that activated, but not resting, T lymphocytes undergo massive NAD+ depletion upon FK866-mediated Nampt inhibition. As a consequence, impaired proliferation, reduced IFN-γ and TNF-α production, and finally autophagic cell demise result. We demonstrate that upregulation of the NAD+-degrading enzyme poly-(ADP-ribose)-polymerase (PARP) by activated T cells enhances their susceptibility to NAD+ depletion. In addition, we relate defective IFN-γ and TNF-α production in response to FK866 to impaired Sirt6 activity. Finally, we show that FK866 strikingly reduces the neurological damage and the clinical manifestations of EAE. In conclusion, Nampt inhibitors (and possibly Sirt6 inhibitors) could be used to modulate T cell-mediated immune responses and thereby be beneficial in immune-mediated disorders

Morphoecology in larval fin-fish: A new candidate species for aquaculture, Diplodus puntazzo (Sparidae)

This study was aimed to acquire information on trophic behavior of Diplodus puntazzo larvae and juveniles, by studing the ontogenetic sensory development, except vision. D. puntazzo specimens were observed using a scanning electron (n = 67) and a light microscope (n = 7). The results concerned four ontogenetical stages of sharpsnout seabream: larval, post-larval, transitional, and juvenile stages. The yolk-sac larval stage was not detected as the smallest larvae at our disposal (3.1 mm TL; 2nd day from hatching) showed no external appearance of the yolk. During the larval stage (3.1–4.7 mm TL), sharpsnout seabream is equipped with free neuromasts and olfactory ciliated receptor cells. In the post-larval stage (5– 28.6 mm TL), mechano- and chemo-reception is implemented: the inner and outer taste buds differentiation, the nasal formation, the lateral line system canalization occur. The precocious differentiation of chemo-receptors makes post-larvae particularly sensitive to the organoleptic properties of administered preys. D. puntazzo, at the end of this phase, could be considered a juvenile (complete squamation is acquired), except for the mouth and pharyngeal teeth. During the subsequent phase (‘transitional’), in fact, eight chisel-type and two lateral series of molar-like teeth progressively substituted the conical ones on each jaw, and three different types of teeth on the upper and lower pharynx differentiated. So, the juvenile phase is reached in individuals longer than 58 mm TL

MOCVD growth and structural characterization of In-Sb-Te nanowires

In this work, the self-assembly of In3Sb1Te2 and In-doped Sb4Te1 nanowires (NWs) for phase change memories application was achieved by metal organic chemical vapor deposition, coupled with vapor–liquid–solid (VLS) mechanism, catalyzed by Au nanoparticles. Single crystal In3Sb1Te2 and In-doped Sb4Te1 NWs were obtained for different reactor pressures at 325 °C. The parameters influencing the NW self-assembly were studied and the compositional, morphological, and structural analysis of the grown structures was performed, also comparing the effect of the used substrate (crystalline Si and SiO2). In both cases, NWs of several micrometer in length and with diameters as small as 15 nm were obtained

Meteorological and geographical control on stable isotopic signature of precipitation in a western Mediterranean area (Tuscany, Italy): Disentangling a complex signal

The stable isotopes of oxygen and hydrogen in precipitation are widely used to track processes occurring within the hydrological cycle and understand regional atmospheric patterns that influence a specific area. Moreover, the oxygen isotopic composition of continental carbonates is extensively used for palaeohydrological reconstruction. Nevertheless, few comprehensive investigations have been performed in the Western Mediterranean to analyze the statistical relationships between oxygen and hydrogen stable isotopes in precipitation and meteorological variables. For understanding the factors that regulate the rainfall stable isotopic signature at present day in this area of Mediterranean region we selected the Tuscany region (central Italy), due to its considerable climatic seasonality, complex morphology and orography. Tuscany is affected by both Atlantic atmospheric disturbances from NW and moist air masses originated in the Mediterranean, and also by the secondary cyclogenesis center of the Gulf of Genoa, the most active in the entire Mediterranean. The ideal position of the Tuscany region thus offers the opportunity to investigate the complex influence of moisture sources on the rainfall isotopic composition. Moreover, in this region many hydrogeological and palaeohydrological studies were performed and require a more precise and quantitative interpretation. In this work, 644 isotope monthly data (δ18O, δ2H, and deuterium excess) of precipitation collected in 12 sites through Tuscany from 1971 to 2018 were gathered in a database. Then, only sites whose monthly data covered almost one year were considered for processing, resulting in 553 precipitation samples archived along with monthly mean temperature and rainfall amount. In this framework, the LMWL for Tuscany was determined by applying different regression techniques and statistical analyses were performed to define the influence of meteorological and geographical variables on the rainfall isotopic composition. The outcomes point out the variations of rainfall isotopic signature as result of several climate and geographical variables than a univocal proxy for both local temperature and precipitation amount. The Atlantic and Mediterranean moisture sources differently contribute for generating the observed isotopic variability, and their influence may seasonally change. Overall, the temperature and amount effect allow to explain the 50% of the isotopic variability, but temperature appears to be more important. These local effects are more pronounced during the periods with low rainfall (spring and summer), whereas the large-scale processes (moisture origin, trajectories, and rainout) are prevailing in winter and autumn. The altitude effect is the main driver of isotopic spatial variability. The deuterium excess parameter is revealed to be a very complex but useful signal for disentangling the different contribution of Atlantic and Mediterranean sources in Tuscan precipitation, even if it is sometime misused

MOCVD growth and thermal analysis of Sb2Te3 thin films and nanowires

Sb2 Te3 is a chalcogenide compound of great interest, due to its applications in the fields of phase change, thermoelectric devices, as well as of topological insulators. In this work, the MOCVD deposition of both Sb 2 Te 3 thin films and nanowires was performed by using the same set of precursors and exploiting the low temperature deposition for thin films and VLS mechanisms for nanowires. A special attention was dedicated to the analysis of the thermal properties, performed by scanning thermal microscopy and modulated photothermal radiometry techniques. The thermal conductivity of the thin layers was compared to that of a nanowire, finding that the values are comparable to those reported for bulk Sb2 Te3