DLI-CVD of TiO2–Cu antibacterial thin films: Growth and characterization

TiO2–Cu nanocomposite films were grown by pulsed direct liquid injection chemical vapor deposition (DLICVD) on stainless steel, silicon and glass substrates with the goal to produce bactericidal surfaces. Copper bis (2,2,6,6-tetramethyl-3,5-heptadionate), Cu(TMHD)2, and titanium tetra-iso-propoxide, TTIP, were used as metalorganic precursors. Liquid solutions of these compounds in xylene were injected in a flash vaporization chamber connected to a cold wall MOCVD reactor. The deposition temperature was typically 683 K and the total pressure was 800 Pa. The copper content of the layers was controlled by the mole fraction of Cu (TMHD)2 which was adjusted by the injection parameters (injection frequency and concentration of the starting solution). The chemical, structural and physical characteristics of the films were investigated by XRD, XPS, FEG-SEM and TEM. Copper is incorporated as metal particles with a relatively large size distribution ranging from 20 to 400 nm (with a large majority in 20–100 nm) depending on the copper content of the films. The influence of the growth conditions on the structural features and the antibacterial properties of the thin films are reported and discussed

Importation of generic hepatitis C therapies: Bridging the price - access gap in high-income countries

The global burden of hepatitis C infection and the emergence of effective therapies An estimated 80-150 million people are infected with hepatitis C infection (HCV) worldwide, with the highest prevalence rates in low- and medium-income countries of Africa and Asia. HCV-related liver disease mortality is estimated to be half a million per annum.1,2 Chronic HCV treatment was interferon-based for two decades, with the addition of ribavirin (RBV),3 pegylated-interferon (PEG-IFN)4 and initial protease inhibitor direct acting antiviral (DAA) therapies (telaprevir, boceprevir)5,6 subsequently providing stepwise improvements in the rate of sustained virological response (SVR). Despite these improvements, interferon-containing HCV therapy uptake remained low in most countries, ranging from <1% to a maximum of 5% of people with chronic HCV initiating therapy each year.7 Fortunately, recent years have seen a revolution in HCV therapeutic development, with the advent of interferon-free DAA therapies, which disrupt replication through inhibition of HCV protease, polymerase and NS5A function.8 Simple (single daily dosing oral regimens), highly tolerable, short-duration (8-24 weeks) regimens with extremely high efficacy (cure rates above 95%) have been developed and registered internationally. Used in various combinations depending on HCV genotypes and previous treatment exposure, these include: sofosbuvir/ledipasvir ,9-11 paritaprevir/ritonavir/ombitasvir/dasabavir/+/-ribavirin ,12-14 sofosbuvir/daclatasvir,15,16 elbasvir/grazoprevir,17,18 and sofosbuvir/velpatasvir. There is clear evidence that HCV cure impacts HCV-related liver disease and hepatocellular carcinoma (HCC) risk.19 Early treatment may have greater benefit. Furthermore, as a result of the high efficacy and tolerance, and ease of delivery of these medications, HCV treatment as prevention is being explored in some countries, particularly treating high prevalence populations, such as people who inject drugs and incarcerated populations.20 The broad implementation of these therapeutic regimens has the potential to dramatically impact HCV-related disease burden globally. Indeed, new HCV treatments have been deemed so important that some (sofosbuvir, daclatasvir) were added to the 2015 WHO Essential Medicines List along with a number of their combinations.NHMRC project grant, App 108067

Pressure dependence of the charge-density-wave gap in rare-earth tri-tellurides

We investigate the pressure dependence of the optical properties of CeTe$_3$, which exhibits an incommensurate charge-density-wave (CDW) state already at 300 K. Our data are collected in the mid-infrared spectral range at room temperature and at pressures between 0 and 9 GPa. The energy for the single particle excitation across the CDW gap decreases upon increasing the applied pressure, similarly to the chemical pressure by rare-earth substitution. The broadening of the bands upon lattice compression removes the perfect nesting condition of the Fermi surface and therefore diminishes the impact of the CDW transition on the electronic properties of $R$Te$_3$.Comment: 5 pages, 4 figure

Comparative study of antibacterial efficiency of M-TiO2 (M = Ag, Cu) thin films grown by CVD

M-TiO2 (M = Ag, Cu) nanocomposite layers were grown by pulsed direct liquid injection chemical vapor deposition (DLICVD) on various substrates to produce bactericidal surfaces with long term activity. Monodisperse Ag nanoparticles (NPs) with an average size of 5-10 nm are embedded in an anatase matrix. A bactericidal behavior determined by the JIS Z 2801 standard test was found for Ag-TiO2 films for Ag ≤ 1 at. % and above. Higher Ag content is not necessary since efficiency is already at its maximum (relative activity 100%). By contrast, using Cu as antibacterial agent, a larger size distribution of metal particles was found (20 to 400 nm). Cu-TiO2 films exhibit a bactericidal behavior if their thickness is higher than 100 nm and Cu content ≥ 3.5 at. %. These coatings are still antibacterial after 5 months of aging and their efficiency has decreased by only 35%

Studies on the cytokinins in fruits I. Occurrence and levels of cytokinin-like substances in grape berries at different developmental stages

The occurrence and levels of cytokinin-like substances in the berries of Bangalore Blue grapes were studied at different stages of growth. The concentration of cytokinins was maximum cluring anthesis ancl the first rapid growth period. The level of cytokinins cleclined markedly cluring the lag and subsequent rapid growth phase. Two growth promoting zones were cletectecl by soybean callus bioassay in the thin layer chromatographs of berry extracts, at all stages of sampling. Although the identity of cytokinin-like substances has not been establishecl, the present study supports the hypothesis that besides auxins, gibberellins, abscisic acid and ethylene, cytokinins are also involvecl in the growth and development of grape berries.Untersuchungen über die Cytokinine in FrüchtenI. Vorkommen und Gehalt cytokininartiger Substanzen in Traubenbeeren verschiedenen EntwicklungszustandesIn verschiedenen Entwicklungsstadien der Beeren von Bangalore Blue wurden das Auftreten und die Menge cytokininartiger Substanzen untersucht. Die Cytokininkonzentration war während der Anthese und der ersten Phase raschen Wachstums am höchsten. Während der anschließenden Phase verlangsamten Wachstums und der darauf folgenden Phase erneuten starken Wachstums fiel die Cytokininkonzentration deutlich ab. Mit Hilfe des Sojabohnenkallus-Tests wurden auf den Dünnschichtchromatogrammen von Beerenextrakten aller Entwicklungsstadien zwei wachstumsfördernde Zonen nachgewiesen. Obgleich die cytokininartigen Substanzen nicht identifiziert wurden, wird durch die vorliegende Untersuchung doch die Hypothese gestützt, daß neben Auxinen, Gibberellinen, Abscisinsäure und Äthylen auch Cytokinine in das Wachstums- und Entwicklungsgeschehen der Traubenbeeren eingeschaltet sind

SCFAs strongly stimulate PYY production in human enteroendocrine cells.

Peptide-YY (PYY) and Glucagon-Like Peptide-1 (GLP-1) play important roles in the regulation of food intake and insulin secretion, and are of translational interest in the field of obesity and diabetes. PYY production is highest in enteroendocrine cells located in the distal intestine, mirroring the sites where high concentrations of short chain fatty acids (SCFAs) are produced by gut microbiota. We show here that propionate and butyrate strongly increased expression of PYY but not GCG in human cell line and intestinal primary culture models. The effect was predominantly attributable to the histone deacetylase inhibitory activity of SCFA and minor, but significant contributions of FFA2 (GPR43). Consistent with the SCFA-dependent elevation of PYY gene expression, we also observed increased basal and stimulated PYY hormone secretion. Interestingly, the transcriptional stimulation of PYY was specific to human-derived cell models and not reproduced in murine primary cultures. This is likely due to substantial differences in PYY gene structure between mouse and human. In summary, this study revealed a strong regulation of PYY production by SCFA that was evident in humans but not mice, and suggests that high fibre diets elevate plasma concentrations of the anorexigenic hormone PYY, both by targeting gene expression and hormone secretion

Action du sulfite de sodium sur la concentration en composés organohalogénés et sur l'activité mutagène de solutions chlorées de substances humiques

Cette étude a eu pour but de déterminer l'effet d'un traitement par le sulfite de sodium sur la concentration en composés organohalogénés totaux (TOX) et sur l'activité mutagène de solutions chlorées de substances humiques d'origine aquatique (SHA), après avoir cherché à préciser l'influence du pH et du temps sur la concentration en TOX.Les résultats obtenus à partir d'échantillons chlorés de SHA en absence de chlore résiduel ont permis de mettre en évidence une diminution de la concentration en composés organohalogénés totaux, soit par stockage en milieu neutre ou basique, soit par addition de sulfite de sodium. L'intensité de cette réduction de la concentration en TOX augmente avec le pH, le temps de réaction et la dose de sulfite de sodium introduite.Les résultats obtenus à partir d'échantillons contenant du chlore libre indiquent que seule une déchloration totale avec un excès de sulfite de sodium peut conduire, en milieu neutre, à une diminution de l'activité mutagène et de la concentration en TOX des solutions diluées de SHA. La comparaison des pourcentages d'abattement obtenus sur le paramètre TOX et sur l'activité mutagène indique que la diminution de la génotoxicité par déchloration totale est due à l'action du sulfite sur des composés mutagènes non chlorés ou sur des composés chlorés fortement mutagènes et ne représentant qu'une très faible fraction du TOX.If is a well known tact that mimerous organohalogenated compounds are formed during the chlorination (preoxidation or final disinfection) of drinking water. Some of these compounds have been shown to be mutagenic. Recent studies have suggested that a treatment with oxygenated derivatives of SIV (SO2, NaHSO3 and Na2SO3) could reduce the genotoxicity of chlorinated drinking water.The general aim of Ibis study was to determine the effect of dechlorination treatments on the mutagenic activity of chlorinated drinking water. The following experiments were carried out in order to point out the effect of a treatment with sodium sulfite on the concentration of total organohalogenated compounds (TOX) and on the mutagenic activity of chlorinated dilute solutions of Aquatic Humic Substances (AHS).At first, the affects of pH, sodium sulfite dose and contact time on TOX concentration were investigated. Then, the importance of the dechlorination rate (partial or complete) on TOX concentration and also on the mutagenic activity could be studied.ExperimentalAquatic Humic Substances (natural mixture of fulvic and humic acids) were dissolved in phosphate-buffered ultra-pure water at 5 and 15 mg l-1 concentrations (pH 6.1 and 6.9 respectively). Stock solutions of chlorine were prepared in the laboratory and titrated by iodometry. Chlorination and dechlorination treatments were carried out in headspace-free baffles, at 20± 1 °C in the dark. Residual chlorine was determined by spectrophotometric measurements at 510 nm, following the calorimetric method using N,N-diethylphenylene-1,4-diamine (DPD). To avoid the slow oxidation of Slv into Svl by dissolved oxygen, the sodium sulfite solutions were prepared freshly before use. TOX concentrations were measured using a DOHRMAN DX-20 TOX analyser equipped with a MC-1 microcoulometric cell and with an AD-2 adsorption module. Before analysis, the residual chlorine was neutralized with sodium thiosulfate and samples were acidified to pH 1.4.The mutagenic activity was determined using acetone-dichloromethane extracts (AMBERLITE XAD-8 and XAD-2 resins) of the aqueous samples of chlorinated and dechlorinated solutions of AHS, acidified to pH 2.0 before extraction. The mutagenicity tests were carried out on TA 98 and TA 100 tester strains, following the method described by MARON and AMES (1983).Results-Effect of pH, addition of sodium sulfite and storage time on the TOX concentrationThe experiments carried out with dilute solutions of AHS ([AHS] = 5 mg 1-1; DOC = 2.5 mg Cl-1; pH = 6.1) showed a linear relationship between TOX production and chlorine consumption in the range 0-2.0 mg Cl2 l-1 (fig. 2).15 % of the chlorine demand was incorporated as organic chlorine in molecules.Experiments performed on solutions containing no residual free chlorine showed that organohatogenated compounds could be partially destroyed upon storage at neutral or basic pH (table 1). Reductions in TOX concentrations of 10 % at pH 6.1-8.5 in 24 hours and of 20 % at pH 11.5 in 2 hours were observed. This was enhanced by increasing the storage time.The addition of sodium sulfite (100 µmol l-1) in solutions containing no residual free chlorine significantly reduced the TOX concentration (10 % in 2 hours at pH 6.1-8.5; table 1). This reduction was enhanced by increasing sulfite dose and storage time and by increasing pH (30 % in 2 hours at pH 11.5). Furthermore, at a given pH value and for a reaction time of 2 hours, the decrease in TOX concentration was larger in presence of sulfite.- Effect of a dechlorination treatment on the TOX concentrationAs shown in figure 3, a dechlorination treatment (reduction of the residual free chlorine concentration) with sodium sulfite could significantly reduce the TOX concentration of the dilute solutions of AHS at pH 6.1 only if an excess of the dechlorinating agent was added. This effect was enhanced by increasing the excess of sulfite but nevertheless seemed to be limited (less than 15 % of reduction for the highest doses used; table 2).The free chlorine residuals measured after a 2 hours partial dechlorination confirmed the stoichiometric factor of 1 mole/mole for the reaction between chlorine and sodium sulfite.- Effect of a dechlorination treatment on the mutagenic activity and on the TOX concentrationThe dechlorination treatments were carried out on chlorinated dilute solutions of AHS ([AHS] = 15 mg l-1; DOC 7.5 mg C l-1; pH = 6.9). The TOX concentrations were measured on aqueous solutions and mutagenicity tests were performed on the corresponding acetone-dichloromethane extracts following a solvent exchange (dimethylsulfoxide). The results obtained showed again that only a total dechlorination treatment could reduce the TOX concentration of the aqueous chlorinated solutions and was able to destroy a significant part of the mutagenic activity of the extracts (table 3 and fig. 4).Although the effect of sulfite on TOX concentration seemed limited (less than 7 % reduction for the highest sulfite dose tested), the reduction in the genotoxicity was more important when the excess of sulfite was increased. No correlation between the TOX concentration and the mutagenic activity could be established. The mutagenic compounds destroyed by sodium sulfite do not appear to be organohalogenated ones. If they are, they are present at trace levels and thus are extremely patent and account for a very little part of the TOX concentration

Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Foreground Polarization

We present a full-sky model of polarized Galactic microwave emission based on three years of observations by the Wilkinson Microwave Anisotropy Probe (WMAP) at frequencies from 23 to 94 GHz. The model compares maps of the Stokes Q and U components from each of the 5 WMAP frequency bands in order to separate synchrotron from dust emission, taking into account the spatial and frequency dependence of the synchrotron and dust components. This simple two-component model of the interstellar medium accounts for at least 97% of the polarized emission in the WMAP maps of the microwave sky. Synchrotron emission dominates the polarized foregrounds at frequencies below 50 GHz, and is comparable to the dust contribution at 65 GHz. The spectral index of the synchrotron component, derived solely from polarization data, is -3.2 averaged over the full sky, with a modestly flatter index on the Galactic plane. The synchrotron emission has mean polarization fraction 2--4% in the Galactic plane and rising to over 20% at high latitude, with prominent features such as the North Galactic Spur more polarized than the diffuse component. Thermal dust emission has polarization fraction 1% near the Galactic center, rising to 6% at the anti-center. Diffuse emission from high-latitude dust is also polarized with mean fractional polarization 0.036 +/- 0.011.Comment: 9 pages with 8 figures. For higher quality figures, see the version posted at http://lambda.gsfc.nasa.gov/product/map/dr2/map_bibliography.cf

Interplay of the electronic and lattice degrees of freedom in A_{1-x}Fe_{2-y}Se_{2} superconductors under pressure

The local structure and electronic properties of Rb$_{1-x}$Fe$_{2-y}$Se$_2$ are investigated by means of site selective polarized x-ray absorption spectroscopy at the iron and selenium K-edges as a function of pressure. A combination of dispersive geometry and novel nanodiamond anvil pressure-cell has permitted to reveal a step-like decrease in the Fe-Se bond distance at $p\simeq11$ GPa. The position of the Fe K-edge pre-peak, which is directly related to the position of the chemical potential, remains nearly constant until $\sim6$ GPa, followed by an increase until $p\simeq 11$ GPa. Here, as in the local structure, a step-like decrease of the chemical potential is seen. Thus, the present results provide compelling evidence that the origin of the reemerging superconductivity in $A_{1-x}$Fe$_{2-y}$Se$_2$ in vicinity of a quantum critical transition is caused mainly by the changes in the electronic structure