Nuclear and Non-Ionizing Energy-Loss for Coulomb Scattered Particles from Low Energy up to Relativistic Regime in Space Radiation Environment

In the space environment, instruments onboard of spacecrafts can be affected by displacement damage due to radiation. The differential scattering cross section for screened nucleus--nucleus interactions - i.e., including the effects due to screened Coulomb nuclear fields -, nuclear stopping powers and non-ionization energy losses are treated from about 50 keV/nucleon up to relativistic energies.Comment: Accepted for publication in the Proceedings of the ICATPP Conference on Cosmic Rays for Particle and Astroparticle Physics, Villa Olmo (Como, Italy), 7--8 October, 2010, to be published by World Scientifi

MOCVD growth of Bi2Te3-Sb2Te3 layers : Effect of growth parameters on the electrical and thermoelectrical properties

The growth of (Bi1-xSbx)2Te3 thin films by metal-organic chemical vapour deposition (MOCVD) using trimethylbismuth, triethylantimony and diethyltellurium as bismuth, antimony and tellurium sources respectively is investigated on pyrex substrates. The electrical and thermoelectrical properties of this material are also measured over the growth temperature range 360-470°C. The studies are also made on the effect of VI/V ratio on these properties in the variation range 2-9. Polycrystalline structure is confirmed by X-ray diffraction, and it is observed that the intensity of the preferred orientation is higher at 450°C. The measurement of Seebeck coefficient shows that all samples have p-type conduction. The best value of this parameter is obtained for high growth temperature (240µV/K). The good result obtained for (Bi1-xSbx)2Te3 thin films revealed the great potential of MOCVD method which is an industrial technique to produce good materials for device applications (sensors and thermopiles).The growth of (Bi1-xSbx)2Te3 thin films by metal-organic chemical vapour deposition (MOCVD) using trimethylbismuth, triethylantimony and diethyltellurium as bismuth, antimony and tellurium sources respectively is investigated on pyrex substrates. The electrical and thermoelectrical properties of this material are also measured over the growth temperature range 360-470°C. The studies are also made on the effect of VI/V ratio on these properties in the variation range 2-9. Polycrystalline structure is confirmed by X-ray diffraction, and it is observed that the intensity of the preferred orientation is higher at 450°C. The measurement of Seebeck coefficient shows that all samples have p-type conduction. The best value of this parameter is obtained for high growth temperature (240µV/K). The good result obtained for (Bi1-xSbx)2Te3 thin films revealed the great potential of MOCVD method which is an industrial technique to produce good materials for device applications (sensors and thermopiles)

Effects of Enriched Environment (EE) on Depressive-Like Behavior and Hippocampal Structure in Rat Model of Chronic Stress

Chronic stress is associated with the development of depression. It can trigger structural and neurobehavioral changes in the brain and has been shown to induce depressivelike behavior in animals. An enriched environment can modulate the structure and function of the brain by altering the expression of various genes and proteins as well as affecting neurotransmitters’ activity. The hippocampus plays an important role incontrolling the networks for mood regulation and has been implicated in the course of depression. This study aimed to investigate the effect of an enriched environment on the depressive-like behavior and hippocampal structure in rats after unpredictable chronic mild stress (UCMS) exposure. Male Wistar rats (Rattus novergicus) were divided into three groups, each consisting of 6 rats including the control, UCMS and UCMS+EEgroup. Unpredictable chronic mild stress and EE were given for 21 days. Body weight gain, depressive-like behavior, and hippocampal structure were evaluated at the end of the experiment. Depressive-like behavior was assessed with Forced Swim Test (FST) and Sucrose Preference Test (SPT). Thickness of the pyramidal layer of CA1 and CA3 area were measured with histologic examination to see changes in the hippocampalstructure. Data were analyzed using One-Way ANOVA or Kruskal-Wallis followed by multiple comparison post hoc test. The enriched environment could significantly maintain body weight gain (p = 0.036) and rat’s preference to sucrose solution (p =0.001) in a stressful condition. Enriched environment reduced immobility time in FST but it was not statistically significant (p = 0.177). There was a significant difference in the thickness of CA1 and CA3 pyramidal layer of the hippocampus among groups (p=0.015 and p=0.019 respectively). Stress markedly decreased the thickness of CA1 and CA3 pyramidal layer (p=0.014 and 0.011 respectively). The enriched environment can ameliorate stress-induced depressive-like behavior and alteration in hippocampalstructure in rats. Keywords: Environmental enrichment, depression, stress, hippocampu

A New Biocomposite Material Based on Wheat Waste and Suitable for 3D Printing Applications

Biopolymers, such as poly(lactic) acid (PLA), which is obtained through green synthesis pathways from renewable resources, has attracted considerable interest in recent years because of the increasing need to reduce petroleum-based plastic pollution and bringing their prices comparable with conventional thermoplastic commodities’ price (e.g., polyethylene, polypropylene, and polystyrene). The present work investigates the employment of 10% wt of natural materials, deriving from wheat milling process, as biofiller of PLA to develop a biocomposite filament suitable for 3D-printing technique. The inclusion of a cost-free natural material leads to a strong reduction of the whole material cost. Implementing this new class of composite material to additive manufacturing technique allows to dramatically reduce the environmental impact of 3D printed products

Identification of a novel plasmid lineage associated with the dissemination of metallo-β-lactamase genes among pseudomonads

Acquisition of metallo-\u3b2-lactamases (MBLs) represents one of most relevant resistance mechanisms to all \u3b2-lactams, including carbapenems, ceftolozane and available \u3b2-lactamase inhibitors, in Pseudomonas spp. VIM-type enzymes are the most common acquired MBLs in Pseudomonas aeruginosa and, to a lesser extent, in other Pseudomonas species. Little is known about the acquisition dynamics of these determinants, that are usually carried on integrons embedded into chromosomal mobile genetic elements. To date, few MBL-encoding plasmids have been described in Pseudomonas spp., and their diversity and role in the dissemination of these MBLs remains largely unknown. Here we report on the genetic features of the VIM-1encoding plasmid pMOS94 from P. mosselii AM/94, the earliest known VIM-1-producing strain, and of related elements involved in dissemination of MBL. Results of plasmid DNA sequencing showed that pMOS94 had a modular organization, consisting of backbone modules associated with replication, transfer and antibiotic resistance. Plasmid pMOS94, although not typable according to the PBRT scheme, was classifiable either in MOBF11 or MPFT plasmid families. The resistance region included the class I integron In70, carrying blaVIM-1, in turn embedded in a defective Tn402-like transposon. Comparison with pMOS94-like elements led to the identification of a defined plasmid lineage circulating in different Pseudomonas spp. of clinical and environmental origin and spreading different MBL-encoding genes, including blaIMP-63, blaBIM, and blaVIM-type determinants. Genetic analysis revealed that this plasmid lineage likely shared a common ancestor and had evolved through the acquisition and recombination of different mobile elements, including the MBL-encoding transposons. Our findings provide new insights about the genetic diversity of MBL-encoding plasmids circulating among Pseudomonas spp., potentially useful for molecular epidemiology purposes, and revealed the existence and persistence of a successful plasmid lineage over a wide spatio-temporal interval, spanning over five different countries among two continents and over 20-years