Improving optical transmission of spark-plasma-sintered yag ceramics:Effect of powder conditioning and post-treatments

Three YAG powders were densified by means of spark plasma sintering (SPS), with the aim of developing optically transparent ceramics. The influence of the physico-chemical characteristics of the powders (purity, agglomeration state and stoichiometry) on the sintering and the optical transmission was investigated. Depending on the powder type, different pre-treatments and/or post-treatments were necessary to increase both homogeneity and optical transmission of the densified parts. In the case of agglomerated powders, dispersion by ultrasonication was efficient and led to better homogeneity and higher optical transmission. Post-treatments such as annealing and post-hipping in air were helpful to reduce oxygen vacancies and residual porosities and improved the optical transmission of the ceramics. The highest values of real in-line transmission (RIT) were obtained under SPS conditions of 50 MPa at 1500 °C and after annealing in air at 1150 °C for 12 h

J Virol

In this placebo-controlled phase II randomized clinical trial, 103 HIV-1 infected patients under c-ART (combined antiretroviral treatment) were randomized 2:1 to receive 3 doses of DNA GTU-MultiHIV B (coding for Rev, Nef, Tat, Gag and gp160) at Week (W)0, W4 and W12 followed by 2 doses of LIPO-5 vaccine containing long peptides from Gag, Pol and Nef at W20 and W24 or placebos. Analytical treatment interruption (ATI) was performed between W36 to W48.At W28, vaccinees experienced an increase in functional CD4(+) T cell responses measured (P\textbackslashtextless0.001 for each cytokine compared to W0) predominantly against Gag and Pol/Env and an increase in HIV-specific CD8(+) T cells producing IL-2 and TNF-α (P=0.001 and 0.013, respectively), predominantly against Pol/Env and Nef. However, analysis of T cell subsets by mass cytometry in a subpopulation showed an increase of W28/W0 ratio for memory CD8(+) T cells co-expressing exhaustion and senescence markers such as PD-1/TIGIT (P=0.004) and CD27/CD57 (P=0.044) in vaccinees compared to placebo. During ATI, all patients experienced viral rebound with a maximum observed HIV RNA level at W42 (median: 4.63 log(10) cp/ml; IQR 4.00-5.09) without any difference between arms. No patient resumed c-ART for CD4 cell count drop. Globally, the vaccine strategy was safe. However, a secondary HIV transmission during ATI was observed.These data show that the prime-boost combination of DNA and LIPO-5 vaccines elicited broad and polyfunctional T cells. The contrast between the quality of immune responses and the lack of potent viral control underscores the need of combined immunomodulatory strategies.IMPORTANCE In this placebo-controlled phase II randomized clinical trial, we evaluated the safety and immunogenicity of a therapeutic prime-boost vaccine strategy using a recombinant DNA vaccine (GTU®-MultiHIV B clade) followed by a boost vaccination by a lipopeptide vaccine (HIV-LIPO-5) in HIV-infected patients while on combined antiretroviral therapy. We show that this prime-boost strategy is well tolerated, consistently with previous studies in HIV-1 infected individuals and healthy volunteers who received each vaccine component individually. Compared to placebo group, vaccines elicited strong and polyfunctional HIV-specific CD4(+) and CD8(+) T cell responses. However, these immune responses presenting some qualitative defects were not able to control viremia following antiretroviral treatment interruption as no difference in HIV viral rebound was observed in vaccine and placebo groups. Several lessons were learned from these results pointing out the urgent need to combine the vaccine strategies with other immune-based interventions

AIDS

OBJECTIVES: This study aimed to determine the timing and level of HIV rebound in blood and seminal plasma and to characterize the HIV rebounding populations after antiretroviral treatment interruption (ATI) in HIV-1-infected participants enrolled in a therapeutic vaccine trial. DESIGN: A twelve-week (W) ATI period was proposed at W36 to patients enrolled in the VRI02/ANRS149-LIGHT trial. Paired blood and semen samples were collected before (W32 or W36) and during ATI (W38, W40, W42, W44 and W48). METHODS: HIV-RNA and HIV-DNA were quantified sequentially from blood and semen samples. Ultradeep sequencing (UDS, Roche/454) of partial env HIV-DNA/RNA (C2V3) was performed in both compatments. RESULTS: HIV-RNA rebounded in blood plasma and seminal plasma of all ten participants after ATI (median peak of 5.12 log10 cp/ml [range: 4.61-6.35] and 4.26 log10 cp/ml [3.20-4.67], respectively). HIV-RNA rebound was detected in blood plasma as soon as W38 in 8/10 patients, and in seminal plasma between W38 and W40 in 8/10 patients. Phylogenetic approaches showed intermingled HIV-RNA populations from plasma and semen during ATI, suggesting a lack of viral compartmentalization between blood and semen. CONCLUSION: Our data demonstrate rapid and high HIV rebound in semen after ATI, raising concerns about high risk of HIV sexual transmission during HIV cure trials

Electrochemical Write and Read Functionality through Oxidative Dimerization of Spiropyran Self-Assembled Monolayers on Gold

In contrast to their photochromism, the electrochemistry of spiropyrans in self-assembled monolayers has attracted only modest attention in recent years. In this contribution the electrochemical oxidation of self-assembled monolayers (SAMs) of 6-nitro-BIPS spiropyran (SP) prepared on polycrystalline gold surfaces is described. The SAMs were characterized with cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), surface-enhanced Raman scattering (SERS), and UV/vis absorption spectroelectrochemistry. The electrochemical oxidation of spiropyrans in solution results in aryl C−C coupling of the indole units and thereby the formation of a symmetric spiropyran dimer. Comparison of spectroscopic data obtained for electrochemically oxidized spiropyran dimers in solution with data from monolayers confirms that a similar oxidative coupling occurs in the SAMs on gold also. The dimer formed can be oxidized electrochemically to monocationic and dicationic states and shows remarkably good stability in UHV and ambient conditions in all three redox states. In addition, the dimerized spiropyran self-assembled monolayer show photochromism, which was characterized by XPS and SERS spectroscopy.

Investigation of the resonance Raman spectra and excitation profiles of a monometallic ruthenium(II) [Ru(bpy)2(HAT)]2+ complex by time-dependent density functional theory.

The resonance Raman (RR) properties of the [Ru(bpy)(2)(HAT)](2+) (where bpy = 2,2'-bipyridine and HAT = 1,4,5,8,9,12-hexaazatriphenylene) complex have been investigated by means of time-dependent density functional theory calculations employing the hybrid B3LYP-35 XC functional and by including the effects of the solvent within the polarizable continuum model approach. Analysis of the electronic excited-state energies has demonstrated that mainly four different metal-to-ligand charge-transfer excitations contribute to the first absorption band in vacuo and water. The simulation of the absorption spectra by including the vibronic structure of the states has shown a general agreement with the experimental spectrum recorded in water. Furthermore, significant variations of the excited-state energies and compositions have been found when the effects of the solvent are included. Calculation of the short-time-approximation RR spectra has provided the vibrational signature of each contributing state and has shown that considering only one excited state is not sufficient to accurately simulate the RR spectra for excitation frequencies in resonance with the first absorption band. A comparison of the RR spectra calculated using the vibronic theory for different excitation wavelengths with the measured spectra at 514 and 458 nm has demonstrated that inclusion of the solvent effects in the simulation scheme leads to substantial improvements of the RR intensity patterns, which allow assignment of the vibrational bands. In particular, the calculations are able to reproduce the variations of the HAT and bpy RR intensities as illustrated by their RR excitation profiles, highlighting the strong dependence of the RR intensities with respect to the excitation frequency.Journal Articleinfo:eu-repo/semantics/publishe