Effects of thermal annealing on the properties of zirconia films prepared by ion-assisted deposition

The effect of thermal annealing in the range 300–800 °C on the properties of zirconia films prepared by ion assisted deposition was studied. It was found that at low temperature the cubic phase is formed. This phase is stable up to 700 °C. All the films exhibit a monophasic monoclinic structure at 800 °C. The stress, estimated from X-ray patterns, shows a transition from tensile to compressive with increasing ion fluence. The refractive index and extinction coefficient do not seem to change appreciably up to 700 °C, showing a marked degradation thereafter. Single step annealing to the highest temperature was found to result in better stability than multistep annealing.

Kinetics of ceric ion oxidation of naphthalene and its derivatives. Formation of the radical cation intermediate in the rate limiting step

Ceric ammonium sulfate, CAS, oxidizes naphthalene to 1,4-naphthoquinone in essentially quantitative yield in CH3CN-dil. H2SO4. Stoichiometric studies indicate that 6 mol of CAS are required for the oxidation of 1 mol of naphthalene to 1,4-naphthoquinone. Kinetic investigations reveal that the reaction takes place through initial formation of a 1:1 complex of naphthalene and cerium(IV) in an equilibrium step followed by slow decomposition of the complex to naphthalene radical cation. Kinetic results on the effects of acid strength, polarity of the medium, temperature and substituents are in accordance with this mechanism. Further conversion of the radical cation into 1,4-naphthoquinone takes place in fast steps involving a further 5 mol of cerium(IV) and 2 mol of H2O.

Microscopic theory of solvation of an ion in a binary dipolar liquid

A microscopic theory of the statics and the dynamics of solvation of an ion in a binary dipolar liquid is presented. The theory properly includes the different intermolecular correlations that are present in a binary mixture. As a result, the theory can explain several important aspects of both the statics and the dynamics of solvation that are observed in experiments. It provides a microscopic explanation of the preferential solvation of the more polar species by the solute ion. The dynamics of solvation is predicted to be highly non-exponential, in general. The average relaxation time is found to change nonlinearly with the composition of the mixture. These predictions are in qualitative agreement with the experimental results.

Molecular theory of ion solvation dynamics in water, acetonitrile and methanol: A unified microscopic description of collective dynamics in dipolar liquids

A recently developed microscopic theory of solvation dynamics in real dipolar liquids is used to calculate, for the first time, the solvation time correlation function in liquid acetonitrile, water and methanol. The calculated results are in excellent agreement with known experimental and computer simulation studies.

Bacteriophage therapy for Staphylococcus aureus bacteremia in streptozotocin-induced diabetic mice

The protective effect of bacteriophage was assessed against experimental Staphylococcus aureus lethal bacteremia in streptozotocin (STZ) induced-diabetic and non-diabetic mice. Intraperitoneal administrations of S. aureus (RCS21) of 2 x 10(8) CFU caused lethal bacteremia in both diabetic and non-diabetic mice. A single administration of a newly isolated lytic phage strain (GRCS) significantly protected diabetic and nondiabetic mice from lethal bacteremia (survival rate 90% and 100% for diabetic and non-diabetic bacteremic groups versus 0% for saline-treated groups). Comparison of phage therapy to oxacillin treatment showed a significant decrease in RCS21 of 5 and 3 log units in diabetic and nondiabetic bacteremic mice, respectively. The same protection efficiency of phage GRCS was attained even when the treatment was delayed up to 4 h in both diabetic and non-diabetic bacteremic mice. Inoculation of mice with a high dose (10(10) PFU) of phage GRCS alone produced no adverse effects attributable to the phage per se. These results suggest that phages could constitute valuable prophylaxis against S. aureus infections, especially in immunocompromised patients. (C) 2010 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Properties of ion assisted deposited titania films

Thin films of titanium dioxide have been deposited using ion assisted deposition with oxygen ions in the energy range 100�500 eV and current densities up to 100 ?A/cm2. It has been observed that the refractive index of the films increases up to 300 eV and the extinction coefficient increased only nominally up to 300 eV. Optical band gap calculations have shown a strong dependence of the gap on the energy of incident ions. Beyond a critical energy and current density of the ions the refractive index and extinction coefficient of the films start deteriorating. It has also been found that beyond the critical values the optical band gap value decreases. The maximum refractive index obtained was 2.49 at an energy of 300 eV and 50 ?A/cm2 current density. Post?deposition annealing of the films at 500?°C resulted in a slight increase in refractive index without affecting the extinction coefficient. X?ray diffraction studies revealed a monophasic anatase structure in these films. ?

Elliptic flow of thermal photons in heavy-ion collisions at Relativistic Heavy Ion Collider and Large Hadron Collider

We calculate the thermal photon transverse momentum spectra and elliptic flow in $\sqrt{s_{NN}} = 200$ GeV Au+Au collisions at RHIC and in $\sqrt{s_{NN}} = 2.76$ TeV Pb+Pb collisions at the LHC, using an ideal-hydrodynamical framework which is constrained by the measured hadron spectra at RHIC and LHC. The sensitivity of the results to the QCD-matter equation of state and to the photon emission rates is studied, and the photon $v_2$ is discussed in the light of the photonic $p_T$ spectrum measured by the PHENIX Collaboration. In particular, we make a prediction for the thermal photon $p_T$ spectra and elliptic flow for the current LHC Pb+Pb collisions.

Synthesis and characterization of single-crystalline alpha-MoO3 nanofibers for enhanced Li-ion intercalation applications

High quality, single-crystalline alpha-MoO3 nanofibers are synthesized by rapid hydrothermal method using a polymeric nitrosyl-complex of molybdenum(II) as molybdenum source without employing catalysts, surfactants, or templates. The possible reaction pathway is decomposition and oxidation of the complex to the polymolybdate and then surface condensation on the energetically favorable 001] direction in the initially formed nuclei of solid alpha-MoO3 under hydrothermal conditions. Highly crystalline alpha-MoO3 nanofibers have grown along 001] with lengths up to several micrometres and widths ranging between 280 and 320 nm. The alpha-MoO3 nanofibers exhibit desirable electrochemical properties such as high capacity reversibility as a cathode material of a Li-ion battery.

Ion probing with Luminescent PbS Quantum dots in PVA

The PbS quantum dots synthesized in PVA are used to investigate their photoluminescence (PL) response to various ions such as Zn, Cd, Hg, Ag, Cu, Fe, Mn, Co, Cr and Ni ions. The enhancement in the photoluminescence intensity is observed with specific ions namely Zn, Cd, Hg and Ag. Among these four ions, the PL response to Hg and Ag even at sub-micro-molar concentrations is quite high, approximately an order of magnitude higher than Zn and Cd. It is interesting to observe that the change in Pb and S molar ratio has profound effect on the selectivity of these ions. The samples prepared under excess of S are quite effective compared to Pb. Indeed, the later one has hardly any effect on the photoluminescence response. These results also indicate that the sensitivity of these QDs could be fine-tuned by controlling the S concentration at the surface. Contrary to the above, Cu, Fe and Co quenches the photoluminescence. Another interesting property of PbS in PVA observed is photo-brightening mechanism due to the curing of the polymer with laser. However, the presence of excess ions at the surface changes its property to photo-darkening/brightening that depends on the direction of carrier transfer mechanism (from QDs to the surface adsorbed metal ions or vice-versa), which is an interesting feature for metal ion detectivity.

Influence of water and thermal history on ion transport in lithium salt-succinonitrile plastic crystalline electrolytes

Important issues of water and thermal history affecting ion transport in a representative plastic crystalline lithium salt electrolyte: succinonitrile (SN)-lithium perchlorate (LiClO4) are discussed here. Ionic conductivity of electrolytes with high lithium salt amounts (similar to 1 M) in SN at a particular temperature is known to be influenced both by the trans-gauche isomerism and ion association (solvation), the two most important intrinsic parameters of the plastic solvent. In the present study both water and thermal history influence SN and result in enhancement of ionic conductivity of 1 M LiClO4-SN electrolyte. Systematic observations reveal that the presence of water in varying amounts promote ion-pair dissociation in the electrolyte. While trace amounts (approximate to 1-15 ppm) do not affect the trans-gauche isomerism of SN, the presence of water in large amounts (approximate to 5500 ppm) submerges the plasticity of SN. Subjugating the electrolyte to different thermal protocol resulted in enhancement of trans concentration only. This is an interesting observation as it demonstrates a simple and effective procedure involving utilization of an optimized set of external parameters to decouple solvation from trans-gauche isomerism. Observations from the ionic conductivity of various samples were accounted by changes in signature isomer and ion-association bands in the mid-IR regime and also from plastic to normal crystal transition temperature peak obtained from thermal studies. (C) 2010 Elsevier B.V. All rights reserved.

Ribavirin-Induced Anemia in Hepatitis C Virus Patients Undergoing Combination Therapy

The current standard of care for hepatitis C virus (HCV) infection - combination therapy with pegylated interferon and ribavirin - elicits sustained responses in only similar to 50% of the patients treated. No alternatives exist for patients who do not respond to combination therapy. Addition of ribavirin substantially improves response rates to interferon and lowers relapse rates following the cessation of therapy, suggesting that increasing ribavirin exposure may further improve treatment response. A key limitation, however, is the toxic side-effect of ribavirin, hemolytic anemia, which often necessitates a reduction of ribavirin dosage and compromises treatment response. Maximizing treatment response thus requires striking a balance between the antiviral and hemolytic activities of ribavirin. Current models of viral kinetics describe the enhancement of treatment response due to ribavirin. Ribavirin-induced anemia, however, remains poorly understood and precludes rational optimization of combination therapy. Here, we develop a new mathematical model of the population dynamics of erythrocytes that quantitatively describes ribavirin-induced anemia in HCV patients. Based on the assumption that ribavirin accumulation decreases erythrocyte lifespan in a dose-dependent manner, model predictions capture several independent experimental observations of the accumulation of ribavirin in erythrocytes and the resulting decline of hemoglobin in HCV patients undergoing combination therapy, estimate the reduced erythrocyte lifespan during therapy, and describe inter-patient variations in the severity of ribavirin-induced anemia. Further, model predictions estimate the threshold ribavirin exposure beyond which anemia becomes intolerable and suggest guidelines for the usage of growth hormones, such as erythropoietin, that stimulate erythrocyte production and avert the reduction of ribavirin dosage, thereby improving treatment response. Our model thus facilitates, in conjunction with models of viral kinetics, the rational identification of treatment protocols that maximize treatment response while curtailing side effects.

A crosslinked ``polymer-gel'' rechargeable lithium-ion battery electrolyte from free radical polymerization using nonionic plastic crystalline electrolyte medium

A cross-linked polymer-gel soft matter electrolyte with superior electrochemical, thermal and mechanical properties obtained from free radical polymerization of vinyl monomers in a semi-solid organic nonionic plastic crystalline electrolyte for application in rechargeable lithium-ion batteries is discussed here.

Ab initio molecular orbital calculations on ion pair-water complexes of metal halides and oxides

Ab initio MO calculations are performed on a series of ion-molecular and ion pair-molecular complexes of H2O + MX (MX = LiF, LiCl, NaCl, BeO and MgO) systems. BSSE-corrected stabilization energies, optimized geometrical parameters, internal force constants and harmonic vibrational frequencies have been evaluated for all the structures of interest. The trends observed in the geometrical parameters and other properties calculated for the mono-hydrated contact ion pair complexes parallel those computed for the complexes of the individual ions. The bifurcated structures are found to be saddle points with an imaginary frequency corresponding to the rocking mode of water molecules. The solvent-shared ion pair complexes have high interaction energies. Trends in the internal force constant and harmonic frequency values are discussed in terms of ion-molecular and ion-pair molecular interactions.

The Zintl ion As-7](2-): an example of an electron-deficient As-x radical anion

K(2,2,2-crypt)](2)As-7]center dot THF, 1 (2,2,2-crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo8.8.8]hexacosane) is the first well characterized seven-atom radical anion of group 15. UV-Vis spectroscopy confirms the presence and electronic structure of As-7](2-). Cyclic voltammetry in DMF solution shows the As-7(3) /As-7(2) redox couple as a one-electron reversible process. Theoretical investigations explore the bonding and properties of compound 1.

Bi2W1–xCuxO6–x(0.7[less-than-or-eq]x[less-than-or-eq]0.8): a new oxide-ion conductor

Anion-deficient Aurivillius phases of the general formula, Bi2Wi-xCuxO6-2x, possessing orthorhombic/tetragonal Bi2WO6-like structures, have been synthesized by quenching the oxide melts. The tetragonal phase stabilized for the compositions 0.7 less-than-or-equal-to x less-than-or-equal-to 0.8 is a good oxide-ion conductor in the temperature range 500-900 K, the x = 0.7 composition exhibiting the highest conductivity in the series.