Energetic heavy-Ion and proton generation from ultraintense laser-plasma interactions with solids

Heavy ions with energies up to 430+/-40 MeV have been measured from laser-solid interactions at focused intensities of up to 5x10(19) W/cm(2). Observations of proton emission indicate significant structure in the energy spectrum as well as an angular emission profile which varies with energy. Two qualitatively different components of ion emission are observed: (i) a high-energy component which is likely generated by a combination of "Coulomb explosion" and acceleration by the space charge force from hot electrons which escape the plasma, and (ii) a lower-energy component which forms a ring likely created by magnetic fields in the ablated plasma.     

Photonuclear physics when a multiterawatt laser pulse interacts with solid targets

When a laser pulse of intensity 10(19) W cm(-2) interacts with solid targets, electrons of energies of some tens of MeV are produced. In a tantalum target, the electrons generate an intense highly directional gamma-ray beam that can be used to carry out photonuclear reactions. The isotopes 11C, 38K, (62,64)Cu, 63Zn, 106Ag, 140Pr, and 180Ta have been produced by (gamma,n) reactions using the VULCAN laser beam. In addition, laser-induced nuclear fission in 238U has been demonstrated, a process which was theoretically predicted at such laser intensities more than ten years ago. The ratio of the 11C and the 62Cu beta(+) activities yields shot-by-shot temperatures of the suprathermal electrons at laser intensities of approximately 10(19) W cm(-2).     

Novel imidazole derivatives as antifungal agents: Synthesis,biological evaluation,ADME prediction and molecular docking studies

Abstract

A series of 2-(substituteddithiocarbamoyl)-N-[4-((1H-imidazol-1-yl)methyl)phenyl]acetamide derivatives was designed and synthesized to combat the increasing incidence of drug-resistant fungal infections. All synthesized compounds were characterized by IR, ¹H-NMR, ¹³C-NMR, and HRMS spectra and elemental analyses. Antifungal activity tests were performed against four different fungal strains. Molecular docking studies were performed to investigate the mode of action towards the fungal lanosterol 14α-demethylase, a cytochrome P450-dependent enzyme. ADME studies were carried out and a connection between activities and physicochemical properties of the target compounds was determined. Most of the final compounds exhibited significant activity against Candida albicans and Candida krusei with MIC₅₀ value 12.5?μg/mL. The results of in vitro anti-Candida activity, a docking study and ADME prediction revealed that the newly synthesized compounds have potential anti-Candida activity and evidenced the most active derivative, 5b (2-Pyrrolidinthiocarbonylthio-N-[4-((1H-imidazol-1-yl)methyl)phenyl]acetamide), which can be further optimized as a lead compound.     

CO(III)–NI(II) double substituted bismuth vanadate: synthesis,phase stabilization,and structural and electrical characterization

Samples of Co–Ni double substituted bismuth vanadate, BICO_0.20?x NI _x VOX (Bi₄Co_0.20???x ^(III)Ni _x ^(II)V_1.8O_{10.8???(x/2)???δ} ;0?≤?x?≤?0.20) were synthesized by standard solid state reactions. The influence of Ni substitution for Co on phase stabilization and oxide-ion performance have been investigated using X-ray powder diffraction, differential thermal analysis, and AC impedance spectroscopy. The high conducting γ′-phase was effectively stabilized at room temperature for compositions with x?≥?0.13 whose thermal stability increases with Ni content. The complex plane plots of impedance were typically represented at temperatures below 380 °C, suggesting a major contribution of polycrystalline grains to the overall electrical conductivity. The dielectric permittivity measurements revealed the fact that suppression of the ferroelectric transition is compositionally dependent. Interestingly, the maximum ionic conductivity at lower temperatures (～2.56?×?10^?4 S cm^?1 at 300 °C) was observed for the composition with x?=?0.13. However, a good agreement was generally found between the values of electrical conductivity and corresponding activation energies of conduction.     

Effect of Zn–Ti double substitution on the electrical properties of Bi4V2O11

New samples of the Bi₂Zn_0.1–xTi_xV_0.9O_5.35+x; 0.02 ≤ x ≤ 0.08 system have been synthesized through a standard solid-state reaction route. XRD analysis and differential thermal analysis have been used to characterize the phase structure of samples. The γ′ phase is stabilized to room temperature in all investigated samples. The electrical properties of the BIZNTIVOX system have been studied by using AC impedance spectroscopy. An AC impedance response as a function of frequency (20 Hz–1 MHz) has been used to investigate the electrical conductivity and the dielectric permittivity in the temperature range of 150 °C–700 °C. In this temperature range, the phase transition γ′ to γ has been observed in all the compositions studied. AC impedance spectroscopy indicates that the resistance of samples decreases with increase of temperature. The ionic conductivity of samples appeared as a two-line region in Arrhenius dependence. At 300 °C, the highest ionic conductivity is shown by the composition x = 0.05 (σ₃₀₀ = 1.35 × 10^?4 S cm^?1).     

Visible light-mediated photocatalyzed synthesis of oxazole via intermolecular C?N and C?O bond formation

An efficient visible light-mediated, eosin Y-catalyzed synthesis of oxazole has been developed from benzil with primary amines, that providing a straightforward, green, and environmentally benign access to a wide variety of substituted oxazole-2-amines under mild reaction conditions.     

Phase transition in ceria alumina

Al-doped CeO₂ samples were prepared by conventional solid state reaction. The electrical conductivity of CeO₂ doped with Al₂O₃ has been studied at different temperatures for various molar ratios. The isothermal conductivity increases with dopant concentration due to the vacancy migration phenomenon induced by doping. It has been found that the conductivity increases and shows a jump from 450 to 520°C due to the phase transition of ceria from cubic to orthorhombic type. A slight deflection is seen for 0.5 and 0.6 moles of alumina at about 250°C due to its phase transition from γ to α type. AC impedance measurements proved that the oxide ion conductivity predominantly arises from the grain and grain boundary contribution as two well defined semi-circles are clearly seen. The sample characterization and the study of phase transition changes were done by using X-ray diffraction analysis, Fourier transform infrared spectral and differential scanning calorimetry (DSC) measurements. On increasing the concentration of dopant, the transition temperature shifts towards lower side which is confirmed by DSC as well as conductivity measurements.     

Fixed points of fuzzy contractive and fuzzy locally contractive maps

We establish some fixed point theorems for fuzzy contractive and fuzzy locally contractive mappings on a compact metric space with the d_∞-metric for fuzzy sets. Our results generalized well-known classical results of Edelstein.