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A monocrystalline diamond detector was used for measurements of soft x-ray and ion emission from laser plasma obtained with the use of the PALS Asterix laser at intensities on the order of 1016 W/cm2 and pulse duration of 300 ps. Measurements were performed by varying the laser intensity and the focal position of the laser beam with respect to the target position. The spectra were obtained with the use of a diamond detector, which was without a filter, and showed not only the photopeak due to UV and soft x rays but also the ions emitted from the plasma. The detector was employed with absorbers of different thicknesses to determine, as a first approximation, the energy distribution of soft x-ray emission from the plasma. The time-of-flight technique was employed to determine the ion kinetic energies. [ABSTRACT FROM AUTHOR]

Endothelin-1 (ET-1) is a vasoactive peptide produced by activated astrocytes and microglia and is implicated in initiating and sustaining reactive gliosis in neurodegenerative diseases. We have previously suggested that ET-1 can play a role in the pathophysiology of amyotrophic lateral sclerosis (ALS). Indeed, we reported that this peptide is abundantly expressed in reactive astrocytes in the spinal cord of SOD1-G93A mice and ALS patients and exerts a toxic effect on motor neurons (MNs) in an in vitro model of mixed spinal cord cultures enriched with reactive astrocytes. Here, we explored the possible mechanisms underlying the toxic effect of ET-1 on cultured MNs. We show that ET-1 toxicity is not directly caused by oxidative stress or activation of cyclooxygenase-2 but requires the synthesis of nitric oxide and is mediated by a reduced activation of the phosphoinositide 3-kinase pathway. Furthermore, we observed that ET-1 is also toxic for microglia, although its effect on MNs is independent of the presence of this type of glial cells. Our study confirms that ET-1 may contribute to MN death and corroborates the view that the modulation of ET-1 signaling might be a therapeutic strategy to slow down MN degeneration in ALS. [ABSTRACT FROM AUTHOR]

Spinal neurofibromatosis ( SNF) is a related form of neurofibromatosis 1 ( NF1), characterized by bilateral neurofibromas (histologically proven) of all spinal roots (and, eventually, of all the major peripheral nerve branches) with or without other manifestations of classical NF1. By rigorous application of these criteria to the 98 SNF cases published, we developed: (i) a cohort of 49 SNF patients (21 males and 28 females; aged 4-74 years]: 9 SNF families (21/49), 1 mixed SNF/ NF1 family (1/49) and 27 of 49 sporadic SNF patients (including 5 unpublished patients in this report); and (ii) a group of 49 non- SNF patients including: (a) 32 patients with neurofibromas of multiple but not all spinal roots ( MNFSR): 4 mixed SNF/ MNFSR families (6/32); (b) 14 patients with NF1 manifestations without spinal neurofibromas, belonging to SNF (8/49) or MNFSR families (6/32); (c) 3 patients with neurofibromas in one spinal root. In addition to reduced incidence of café-au-lait spots (67% in SNF vs 56% in MNFSR), other NF1 manifestations were less frequent in either cohort. Molecular testing showed common NF1 gene abnormalities in both groups. The risk of developing SNF vs NF1 was increased for missense mutations [p = 0.0001; odds ratio ( OR) = 6.16; confidence interval ( CI) = 3.14-13.11], which were more frequent in SNF vs MNFSR (p = 0.0271). [ABSTRACT FROM AUTHOR]

In this paper a very sensitive ion collection device, for diagnostic of laser ablated-target plasma, is described. It allows for reducing down to few microvolts the signal threshold at digital scope input. A standard ion collector is coupled to a transimpedance amplifier, specially designed, which increases data acquisition sensitivity by a gain ≈1100 and does not introduce any significant distortion of input signal. By time integration of current intensity, an amount of charge as small as 2.7 × 10-2 pC can be detected for photopeak events. [ABSTRACT FROM AUTHOR]

A 1016 W/cm2 Asterix laser pulse intensity, 1315 nm at the fundamental frequency, 300 ps pulse duration, was employed at PALS laboratory of Prague, to irradiate thick and thin primary CD2 targets placed inside a high vacuum chamber. The laser irradiation produces non-equilibrium plasma with deutons and carbon ions emission with energy of up to about 4 MeV per charge state, as measured by time-of-flight (TOF) techniques by using ion collectors and silicon carbide detectors. Accelerated deutons may induce high D-D cross section for fusion processes generating 3 MeV protons and 2.5 MeV neutrons, as measured by TOF analyses. In order to increase the mono-energetic proton yield, secondary CD2 targets can be employed to be irradiated by the plasma-accelerated deutons. Experiments demonstrated that high intensity laser pulses can be employed to promote nuclear reactions from which characteristic ion streams may be developed. Results open new scenario for applications of laser-generated plasma to the fields of ion sources and ion accelerators. [ABSTRACT FROM AUTHOR]

Isospin dependence of dynamical and thermodynamical properties observed in reactions Ca+ Ca and Ca + Ti at 25 MeV/nucleon has been studied. We used the CHIMERA multi-detector array. Strong isospin effects are seen in the isotopic distributions of light nuclei and in the competition between different reaction mechanisms in semi-central collisions. We will show also preliminary results obtained in nuclear collision Ca + Ca at 25MeV/nucleon, having very high N/Z value in the entrance channel ( N/Z = 1.4). The enhancement of evaporation residue production confirms the strong role played by the N/Z degree of freedom in nuclear dynamics. [ABSTRACT FROM AUTHOR]

Catalytic reactions of the steam reforming (SR) of dimethyl ether (DME) and (bio)ethanol to hydrogen-rich gas were compared in a fixed-bed continuous-flow reactor at temperatures of 550-650 °C under atmospheric pressure over Rh/AlO catalysts in terms of product distribution. Rh/AlO catalysts are able to catalyze the high-temperature SR of both EtOH and DME, but in the latter case, higher H yields are obtained and the catalyst is less prone to coking. The aim of this work is to optimise the hydrogen production. Differences in reaction pathways over DME/HO and EtOH/HO are indicated. [ABSTRACT FROM AUTHOR]

We discuss results on the emission of light clusters in nuclear reactions 40Ca + 40,48Ca,46Ti at 25 MeV/nucleon. They were detected and identified in mass and charge by means of the CHIMERA 4π array. Inclusive emission at forward angles shows that isotopic yields of Li and Be nuclei are related to the N/Z values of entrance channels. Moreover, structure effects and even-odd staggering in charge distributions of intermediate mass fragments emitted at forward angles will be shown. In agreement with previous experimental findings, odd-even effects are clearly visible in N ≈ Z systems, while are less pronounced in the neutron rich collision 40Ca+48Ca. These experimental findings are compared to preliminary data obtained in 40Ca+48Ca. collision at 25 MeV/nucleon. [ABSTRACT FROM AUTHOR]

Isospin effects on dynamics of semi-central collisions involving 40Ca+40Ca, 40Ca+48Ca and 48Ca+48Ca reactions at 25 MeV/nucleon have been investigated. For the selected class of events, the balance between the emission of evaporation residues and the presence of binary-like phenomena seems to be influenced by the neutron to proton ratio (N/Z) of entrance channels. In particular, for neutron-rich systems, evaporation residue emission is enhanced. Experimental observations confirm the key role played by the N/Z degree of freedom on nuclear dynamics at 25 MeV/nucleon. [ABSTRACT FROM AUTHOR]

Laser ion sources are employed with success to generate, in vacuum, any ion species with high current, ion energy, charge states and directivity. Nanosecond infrared laser pulses, with intensities of the order of 1010 W/cm2, induce ablation in metals. Ions are produced in vacuum with energy distribution following the Coulomb-Boltzmann-shifted distribution and are ejected mainly along the normal to the target surface. The free ion expansion process occurs in a constant potential chamber placed at high positive voltage variable between 0 and 30 kV, by means of nose along the normal to the target surface. The electric field reaches 5 kV/cm and is used to accelerate Ti ions emitted from the plasma at the INFN-LNS laser facility. The time-of-flight technique is employed to measure the mean ion energies of the post-accelerated particles. Ion charge states and energy distributions were measured through an ion energy spectrometer. Ion energies, charges per pulse, ion currents and beam directivity of Ti beams were measured, and the results were compared with those coming from simulation programs. [ABSTRACT FROM AUTHOR]

Various aspects observed in the reactions 40Ca+40,48 Ca,46Ti at E=25 MeV/nucleon, studied by means of the CHIMERA detector, will be discussed. An isospin effect on the competition between heavy residue production and binary-like channels has been observed in incomplete fusion events. From the thermodynamical point of view, kinetic energy spectra of protons emitted in fusion-evaporation events were fitted with two maxwellian functions. Despite of the different neutron richness of the populated sources, the average temperatures obtained for the quasi-fused systems are similar (T≃5.2MeV). We also performed a preliminary reconstruction of the excitation energy reached by quasi-fusion sources populated in the studied reactions. [ABSTRACT FROM AUTHOR]

Intermediate energy beams of light exotic nuclei have been produced at LNS by the FRIBs facility. Thanks to these beams, a complex study of the structure of halo nuclei in the 11Be region has been started exploiting the performances of the CHIMERA array. [ABSTRACT FROM AUTHOR]

This paper presents the physical analysis results for the following reactions: 124Sn+64Ni, 124Sn+27Al, 124Sn+58Ni at 35MeV/A and 25 MeV/A. The main goal of this studies was to find observables sensitive to isospin effects and to present the similarities/differences between the systems characterised by various charge asymmetry factor, defined as I = (N - Z)/A. Theoretical simulations based on the Quantum Molecular Dynamics (QMD) model have been performed in order to compare them with the results of the analysis of experimental data. The first phase of the reaction was carried out with the code CHIMERA [1]. The sequential decay of hot fragments was simulated by the code COOLER [2]. The conclusions are as follows: there are observables sensitive to the isospin of the system, such as the Light Charged Particles (LCP) emission and their sensitivity is demonstrated more prominently in the analysis of central collisions at 35 MeV/A. The theoretical calculations do not reproduce these relations well. [ABSTRACT FROM AUTHOR]

Au ions with maximum charge states 58+ and with the kinetic energy in a region of ∼100 MeV were recorded. The influence of various experimental conditions is presented and discussed. [ABSTRACT FROM AUTHOR]

For fragments emitted in the reactions 124Sn + 64Ni and 112Sn + 58Ni at 35 AMeV, isotopic composition and velocity correlations have been studied as a function of the centrality of the collision, using the 4π Chimera multidetector. We have investigated the time scale for fragments formation, in order to distinguish between prompt dynamical and sequential statistical emission. Promptly emitted light fragments (Z ≤9) produced in the mid-rapidity domain are characterised by larger N/Z ratio and stronger angular anisotropies than those produced in sequential statistical emission. Results are compared with stochastic BNV code simulations obtained for primary fragments. Valuable information on the symmetry term of the nuclear equation of state at sub-saturation densities are obtained. [ABSTRACT FROM AUTHOR]

The iodine laser PALS, operated at the fundamental and third harmonic frequencies (wavelengths 1315 and 438 nm, respectively), was used to generate plasmas on various targets (Au,CF2, etc.). The investigation was performed at energies up to 400 and 250 J for 1ω and 3ω, respectively, in the 300 ps pulses. In these conditions several samples of solid state nuclear track detectors CR39 type, have been located at suitable geometrical positions to explore their capability to measure main parameters of ions emitted from the laser-produced plasmas. Track diameters and densities were observed on the uncovered detectors exposed to a lot of laser shots. Emitted ions in the energy range up to few tens of MeV, have been observed on the basis of ion collector TOF spectra. Track pattern results are shown and discussed in comparison with mentioned spectra and simulations. [ABSTRACT FROM AUTHOR]

Diamond monocrystalline detectors were used to characterize radiation and particle emission from laser-generated plasma obtained at Laboratori Nazionali del Sud (LNS) and Plasma Asterix Laser Systems (PALS) laboratories by using a high power pulsed laser intensity of 1010 W/cm2 and 1016 W/cm2, respectively. Al, Ta, Au and CF2 plasmas were obtained in different irradiation conditions. Diamond detectors permitted to measure UV, X-rays, electrons and ions. Time-of-flight technique was employed to separate in time the different contributions. Results indicate that this detector has some advantages with respect to the others, such as the high energy gap, the high energy resolution, the low background current and the possibility to detect simultaneously photons, electrons and ions. [ABSTRACT FROM AUTHOR]

CHIMERA is the only 4π-multidetector, used in intermediate nuclear physics experiments, able to perform mass identification of the reaction products. To this purpose, it employs time of flight measurements done with traditional time to digital converters. In order to improve the resolution in mass identification, we have applied digital signal processing to time of flight measurements. This paper presents the methodology for data analysis, the adopted algorithms and the results obtained at different sampling frequencies (mass identification up to A = 33 for the reaction products produced by a 20.5 MeV/u 20Ne beam on 27 Al target). [ABSTRACT FROM AUTHOR]

Collisions of a very heavy nuclear system, 197Au + 197Au, were studied at the energy of 15 MeV/nucleon with the aim to identify and investigate main macroscopic modes of re-separation of such a heavy nuclear system. The experiment was performed at the INFN LNS laboratory in Catania by using the multidetector array CHIMERA. Along with binary strongly damped collisions, a strong component of a new re-separation mode: the "fast ternary fission" in characteristic nearly co-linear configuration was observed and the time scale of this process was determined. [ABSTRACT FROM AUTHOR]

Biogas generally contains significant quantities of carbon dioxide in addition to methane. A bubbling column reactor operating at atmospheric pressure is proposed for cheap separation and a Mettler RC1 reaction calorimeter was used to build a simplified empirical model for measuring the molar heat of solubility of CO2 in aqueous solutions of monoethanolamine (MEA). Determinations were performed in 12 mass% MEA solutions regenerated at atmospheric pressure and reflux temperature for 3 h. Flows of CO2 from 174 to 917 mL min−1 were used at a reactor temperature of 283 to 353 K. [ABSTRACT FROM AUTHOR]

197Au+197Au collisions at 15 MeV/nucleon were studied using the multidetector array CHIMERA and heavy ion beams from the superconducting cyclotron of LNS Catania. The experiment was aimed at studying the mechanism of energy dissipation in collisions of very heavy systems. In the present contribution we report on a part of our study concentrated on a subject of basically binary damped collisions, in which only two main fragments are formed prior to secondary deexcitation processes. Such "binary" events were selected by using complete information from the exclusive-type data (including all Z ≥ 3 fragments) obtained with the CHIMERA multidetector. Results are compared with predictions of a classical dynamical model of Blocki et al., in which both scenarios of energy dissipation, one-body or two-body dissipation mechanisms, are assumed. [ABSTRACT FROM AUTHOR]

Ternary events originating from the 197Au + 197Au reaction at 15 MeV/nucleon, studied by using the multidetector array CHIMERA at LNS Catania, have been collected in almost complete 2π range of the forward hemisphere of CHIMERA thus extending the angular range of our previously reported preliminary data. Energy- and time calibrations for heavy fragments at large angles were supplemented with an analysis of coincidence events of binary strongly damped reactions. Contrary to the previous preliminary results, the new complete data clearly show presence of sequential fission processes in which one of Au-like nuclei undergoes fission after re-separation of the primary binary system. Mechanism of these two types of reactions observed in our data, sequential fission reactions and prompt ternary processes, are presently studied using comparisons with predictions of the stochastic BNV model of Baran, Colonna and Di Toro and the QMD model of Łukasik. [ABSTRACT FROM AUTHOR]

The digital pulse shape data acquisition (DAQ) system used by the large area telescopes of the 4π-multidetector CHIMERA requires transferring large amount of data to the computer. This is necessary so that the same information can be extracted from the detector pulses as in previous analog based systems. To overcome this problem, we have used a sampling ADC-board equipped with two TigerSHARC digital signal processors. The board receives the data and reconstructs the event parameters online. The data volume is significantly. reduced by transmitting to the DAQ only the reconstructed event parameters. [ABSTRACT FROM AUTHOR]

We study the effect of screening by bound electrons in low energy nuclear reactions. We use molecular dynamics to simulate the reactions involving many electrons: D+ d, D+D, 3He+ d, 3He+D, 6Li+ d, 6Li+D, 7Li+ p, 7Li+ H. Quantum effects corresponding to the Pauli and Heisenberg principles are enforced by constraints in terms of the phase space occupancy. In addition to the well-known adiabatic and sudden limits, we propose a new “dissipative limit” which is expected to be important not only at high energies but in the extremely low energy region. The dissipative limit is associated with the chaotic behavior of the electronic motion. It affects also the magnitude of the enhancement factor. We discuss also numerical experiments using polarized targets. The derived enhancement factors in our simulation are in agreement with those extracted within the R-matrix approach. [ABSTRACT FROM AUTHOR]

The characterization of the molecular mechanisms whereby our brain codes, stores and retrieves memories remains a fundamental puzzle in neuroscience. Despite the knowledge that memory storage involves gene induction, the identification and characterization of the effector genes has remained elusive. The completion of the Human Genome Project and a variety of new technologies are revolutionizing the way these mechanisms can be explored. This review will examine how a genomic approach can be used to dissect and analyze the complex dynamic interactions involved in gene regulation during learning and memory. This innovative approach is providing information on a new class of genes associated with learning and memory in health and disease and is elucidating new molecular targets and pathways whose pharmacological modulation may allow new therapeutic approaches for improving cognition. [ABSTRACT FROM AUTHOR]

Using the 4π CHIMERA detector system we have observed a dynamical, non-equilibrated fission of projectile-like fragments as well as an equilibrated fission component in collisions 124Sn + 64Ni and 112Sn + 58Ni at 35A MeV. The velocity and angular distributions of projectile-like fission fragments were analyzed. The contribution of the "dynamical fission" component is larger in the neutron rich 124Sn + 64Ni system than in the neutron poor 112Sn + 58Ni one. [ABSTRACT FROM AUTHOR]

Collisions of a very heavy 197Au + 197Au system have been studied at an energy of 15 MeV/nucleon with the aim to investigate a possible change of the energy dissipation mechanism from one-body dissipation (presumably dominating at low excitation energies) to two-body dissipation. The experiment was carried out in 4π geometry using the CHIMERA multidetector array. A class of ternary events satisfying nearly complete balance of mass numbers was selected. Preliminary results suggest that the selected ternary events represent mostly prompt ternary partitions of the colliding system, in which the lightest fragment is quite massive. In the light of theoretical predictions of Cârjan, Sierk and Nix this result may imply that the observed ternary reactions are driven by the two-body dissipation mechanism already at 15 MeV/nucleon. [ABSTRACT FROM AUTHOR]

The capability of digital pulse shape technique to acquire data from CHIMERA detection cells (Si-CsI(Tl) telescopes) has been evidenced in our previous works. We have now applied this technique to the charge discrimination of the products stopped in the silicon detectors. Large area totally depleted CHIMERA planar silicon detectors (5 cm × 5 cm area, 300 µm thick) in both rear and front side injection have been used. In preliminary tests full charge identification for the reaction products up to Z = 11 have been obtained for products both crossing (ΔE-E technique) and stopping in the silicon detector, using a 21 MeV/u 20Ne beam at the LNS Superconducting Cyclotron in Catania. The quality of the obtained results clearly indicates that the digital signal processing approach is able to give excellent results in this application, too. [ABSTRACT FROM AUTHOR]

Mass and atomic-number identification (ID) of reaction products is a fundamental requirement of any nuclear reaction study. An effective particle-ID method is demonstrated, based on pulse shape analysis/discrimination (PSD) applied to large-area, single-element silicon detectors. This technique uses commercial electronic modules and achieves atomic number resolution rivaling that typically obtained with multi-element (ΔE - E) detector telescopes. The method is applied to the CHIMERA detector system without compromising its time-of-flight (TOF) resolution. In-beam tests of the PSD method have been performed with large-area, 300-μm thick CHIMERA silicon detectors, measuring particles from the 19F + 12C reaction at Tandem energies. Performance of a simple PSD set up is discussed, for front and rear particle injection. [ABSTRACT FROM AUTHOR]

We have designed, built, and tested an on-line pre- analysis and data-storage unit for the data acquisition system of the 4π-detector CHIMERA. The unit uses special algorithms to perform particle identification and automatic peak detection. It tags in charge each event and stores the results on external unit, together with the raw data. It consists of two commercial 2 GHz workstations connected together through 1 Gb/s Ethernet boards and to the data acquisition system through a 100 Mb/s Ethernet. [ABSTRACT FROM AUTHOR]

We perform molecular dynamics simulations of screening by electrons in low energy nuclear reactions, especially between hydrogen isotopes. Quantum effects that corresponds to the Pauli and Heisenberg principle are enforced by constraints. We show that the enhancement of the average cross-section and of its variance is due to the perturbations induced by the electrons. This gives a correlation between the maximum amplitudes of the inter-nuclear oscillational motion and the enhancement factor. It suggests that the chaotic behaviour of the electronic motion affects the magnitude of the enhancement factor. [ABSTRACT FROM AUTHOR]