Electrochemical characterisation of tetra- and octa-substituted oxo(phthalocyaninato)titanium(IV) complexes

The synthesis and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)-{tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (5b); 2,(3)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-{tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (6b). The electrochemical characterisation of complexes octa-substituted with 4-(benzyloxy)phenoxy (9b), phenoxy (9c) and tert-butylphenoxy (9d) groups is also reported. The cyclic voltammograms of the complexes exhibit reversible couples I–III and couple IV is quasi-reversible for complexes 5a, 5b, 6a and 6b. The first two reductions are metal-based processes, confirmed by spectroelectrochemistry to be due to Ti[superscript IV]Pc[superscript 2−]/Ti[superscript III]Pc[superscript 2−] and Ti[superscript III]Pc[superscript 2−]/Ti[superscript II]Pc[superscript 2−] redox processes and the last two reductions are ring-based processes due to Ti[superscript II]Pc[superscript 2−]/Ti[superscript II]Pc[superscript 3−] and Ti[superscript II]Pc[superscript 3−]/Ti[superscript II]Pc[superscript 4−]. Chronocoulometry confirmed a one-electron transfer at each reduction step. The electrochemistry of the above complexes is also compared to the previously reported 5c, 5d, 6c and 6d

EVOLUZIONE DEL TROPISMO DI HIV-1 IN RELAZIONE ALLE MODIFICAZIONI DI LINFOCITI CD4 E VIREMIA E AL TRATTAMENTO: STUDIO PROSPETTIVO DI COORTE IN PAZIENTI CON INFEZIONE ACUTA/RECENTE E PAZIENTI AIDS PRESENTERS

BACKGROUND: Acute infection and AIDS are more extreme phases of the natural history of HIV infection and the evolution of the virus. The acute infection represents a boost in plasma viremia, even before the immune system is able to prepare a neutralizing response to contain the infection. AIDS represents a decrease in immune competence after a stage of clinical latency. The sequence analyses from amplification of the V3 region of gp120 within the env gene and the correlation with the development of immuno-virological profile of patients in our study allowed us to draw conclusions after comparing the two different phases of the disease. METHODS: We enrolled 36 patients with acute/recent infection (n=20) or AIDS presenters (n=16). V3 sequences were obtained and co-receptor tropism was predicted using the Geno2pheno[coreceptor] algorithm. We analyzed various immuno-virological parameters in relation to the initial tropism of the virus: HIV-RNA, T CD4+ cells, (count and percentage) at baseline, at 6 and 12 months; T CD8+ cells (count) and CD4+/CD8+ ratio at baseline; HIV-RNA zenith and T CD4+ cells nadir. Phylogenetic analysis was performed using bioinformatic tools. RESULTS: Our results demonstrated that a reconstitution of the immune system, evaluated as absolute recovery of CD4+ T cells from baseline to six months in both patient groups, showed a more favorable trend in patients with R5 compared to X4. This was most evident in acute/recent infection (R5: 256.5 cells / \u3bcL; X4: 114 cells / \u3bcL) compared to the advanced stage of AIDS (R5: 81 cells / \u3bcL; X4: 71 cells / \u3bcL). Multivariate analysis performed to assess the independent determinants of immune reconstitution showed a correlation with the two variables of considerable interest in the group of acute/recent infections: a positive correlation between the R5 tropism and the number of CD4 cells in both arms, at 6 and 12 months after therapy. Moreover, this analysis showed that, notwithstanding viral tropism, the gain in the number of CD4+ cells in the course of therapy at six months had an inverse correlation with the level of CD4+ cells at baseline. The risk associated with the advanced stage of the disease (i.e. CD4 counts 64 200 cells/\u3bcL in the arm of AIDS presenters) in accordance with the genotypic tropism confirmed the association between low values of FPR and more advanced stages of the disease. CONCLUSIONS: Evolution of the V3 hypervariable region of gp120 located within the env gene, determining the tropism of the virus, influences the immuno-virological trend in the two cohorts of patients with an acute/recent infection and with an AIDS presentation

Phase transitions in simple and not so simple binary fluids

Compared to pure fluids, binary mixtures display a very diverse phase behavior, which depends sensitively on the parameters of the microscopic potential. Here we investigate the phase diagrams of simple model mixtures by use of a microscopic implementation of the renormalization group technique. First, we consider a symmetric mixture with attractive interactions, possibly relevant for describing fluids of molecules with internal degrees of freedom. Despite the simplicity of the model, slightly tuning the strength of the interactions between unlike species drastically changes the topology of the phase boundary, forcing or inhibiting demixing, and brings about several interesting features such as double critical points, tricritical points, and coexistence domains enclosing `islands' of homogeneous, mixed fluid. Homogeneous phase separation in mixtures can be driven also by purely repulsive interactions. As an example, we consider a model of soft particles which has been adopted to describe binary polymer solutions. This is shown to display demixing (fluid-fluid) transition at sufficiently high density. The nature and the physical properties of the corresponding phase transition are investigated.Comment: 6 pages + 3 figures, presented at the 5th EPS Liquid Matter Conference, Konstanz, 14-18 September 200

Effect of Process Parameter on the in-situ Intermetallic Composite Coating and Microstructural Evolution of Zn-Al2O3 in the Presence of TEA/MEA on Mild Steel

Zn-Al2O3 composite coating electrodeposits have been produced from chloride bath in the presence of Triethanolamine (TEA) and Monoethanolamine (MEA). The plating effect of TEA and MEA as addition agent on the Zn-Al2O3 alloy is investigated using SEM/EDS, x-ray diffraction (XRD) and atomic force microscope (AFM). The mechanical properties were examined through micro-hardness tester. The presence of TEA and MEA as a surface-active additive is also felt to accompany the performance of the fabricated coating. The SEM results for Zn-Al2O3 deposits in the presence of TEA/MEA indicate that surface-active additive have a strong influence on the deposit surface morphology and improved micro-hardness behavior which is assisted by the change in the deposition process parameter

Development and evaluation of a multiple-locus variable-number tandem-repeats analysis assay for subtyping Salmonella Typhi strains from sub-Saharan Africa

Purpose: Molecular epidemiological investigations of the highly clonal Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) are important in outbreak detection and in tracking disease transmission. In this study, we developed and evaluated a multiple-locus variable-number tandem-repeats (VNTR) analysis (MLVA) assay for characterization of S. Typhi isolates from sub-Saharan Africa. Methodology: Twelve previously reported VNTR loci were evaluated and an MLVA assay consisting of five polymorphic loci was adopted. The MLVA assay was developed for use on capillary electrophoresis systems by testing a collection of 50 S. Typhi isolates. This S. Typhi strain panel consisted of six outbreak related isolates and 44 epidemiologically unlinked isolates. Amongst these were nine S.Typhi haplotype H58 isolates. Results: The MLVA assay characterized the 50 isolates into 47 MLVA profiles while PFGE analysis of the same isolates revealed 34 pulsotypes. MLVA displayed higher discriminatory power (Simpson’s index of diversity (DI) 0.998 [95% confidence interval (CI) 0.995–1.000)] as compared to pulsed-field gel electrophoresis [Simpson’s DI 0.984 (95% CI 0.974–0.994)]. Conclusion: The MLVA assay presented in this study is a simple, rapid and more accessible tool that serves as a good alternative to other molecular subtyping methods for S. Typhi

Interfacial investigation and strengthening behaviour of Zn–Ni multifacial TEA/MEA thin films induced by electrodeposition

Zinc–nickel films were obtained by electrocodeposition using electrolytic deposition techniques in the presence of TEOA (C6H15NO3) and a surfactants consisting of triethylamine and monoethylamine with other bath additives. The modified structure of the films was analysed with scanning electron microscopy attached to energy-dispersive spectrometer, atomic force microscope and X-ray diffraction. Micro-hardness and corrosion of the coated body was examined and used as a criterion to justify the adhesion of the crystal deposited. The corrosion resistance of the coated and uncoated composites was studied in 3.5 % sodium chloride static solution using linear polarization technique. The hardness value increased from 38HV—substrate to 180HV—coated body, indicating a 78.89 % improvement. Equally, the corrosion resistance of the deposited matrix was enhanced by 84.62 %

Probing the statistical properties of Anderson localization with quantum emitters

Wave propagation in disordered media can be strongly modified by multiple scattering and wave interference. Ultimately, the so-called Andersonlocalized regime is reached when the waves become strongly confined in space. So far, Anderson localization of light has been probed in transmission experiments by measuring the intensity of an external light source after propagation through a disordered medium. However, discriminating between Anderson localization and losses in these experiments remains a major challenge. In this paper, we present an alternative approach where we use quantum emitters embedded in disordered photonic crystal waveguides as light sources. Anderson-localized modes are efficiently excited and the analysis of the photoluminescence spectra allows us to explore their statistical properties, for example the localization length and average loss length. With increasing the amount of disorder induced in the photonic crystal, we observe a pronounced increase in the localization length that is attributed to changes in the local density of states, a behavior that is in stark contrast to entirely random systems. The analysis may pave the way for accurate models and the control of Anderson localization in disordered photonic crystalsWe thank P T Kristensen and N A Mortensen for fruitful discussions on the simulations and theoretical model and gratefully acknowledge financial support from the Villum Foundation, the Danish Council for Independent Research (Natural Sciences and Technology and Production Sciences) and the European Research Council (ERC consolidator grant). LSFP acknowledges financial support from the Spanish MICINN Consolider Nanolight project (CSD2007-00046

Liquid-microjet photoelectron spectroscopy of the green fluorescent protein chromophore

Green fluorescent protein (GFP), the most widely used fluorescent protein for in vivo monitoring of biological processes, is known to undergo photooxidation reactions. However, the most fundamental property underpinning photooxidation, the electron detachment energy, has only been measured for the deprotonated GFP chromophore in the gas phase. Here, we use multiphoton ultraviolet photoelectron spectroscopy in a liquid-microjet and high-level quantum chemistry calculations to determine the electron detachment energy of the GFP chromophore in aqueous solution. The aqueous environment is found to raise the detachment energy by around 4 eV compared to the gas phase, similar to calculations of the chromophore in its native protein environment. In most cases, electron detachment is found to occur resonantly through electronically excited states of the chromophore, highlighting their importance in photo-induced electron transfer processes in the condensed phase. Our results suggest that the photooxidation properties of the GFP chromophore in an aqueous environment will be similar to those in the protein