376 research outputs found

    Spectral Evidence of Aqueous Activity in Two Putative Martian Paleolakes

    Get PDF
    CRISM observations of putative paleolakes in Cankuzo and Luqa craters exhibit spectral features consistent with the activity of water. The spatial distributions suggest different formation scenarios for each site. In Cankuzo the distribution suggests postimpact alteration whereas in Luqa there are hints of possible formation of a layer of phyllosilicate materials

    Star-shaped oligofluorene truxene macromolecules – synthesis and properties as a function of alkyl chain length (PH-11611YP)

    Get PDF
    Star-shaped oligofluorene truxenes are very promising materials and have demonstrated excellent properties as the gain medium in organic semiconductor lasers (OSLs).1-10 Alkyl chains in oligofluorene truxenes act as solubilizing groups as well as spacers to prevent intermolecular π-π stacking that leads to quenching of the light emission. A new series of star-shaped systems analogous to hexyl oligofluorene truxenes11 with alkyl chains of different lengths (butyl chains and octyl chains) was synthesized. The objective of this study was to investigate the effect of alkyl chain length on the film-forming properties of oligofluorene-truxene materials and, as a result, on their optoelectronic properties for applications as the gain medium in OSLs

    Ultralow-threshold up-converted lasing in oligofluorenes with tailored strong nonlinear absorption

    Get PDF
    Nonlinear optical response in organic semiconductors has been an attractive property for many practical applications. For frequency up-converter lasers, to date, conjugated polymers, fluorescent dyes and small organic molecules have been proposed but their performances have been severely limited due to the difficulty of simultaneously achieving strong nonlinear optical response and high performance optical gain. In this work, we show that structurally designed truxene-based star-shaped oligofluorenes exhibit strong structure-property relationships enabling enhanced nonlinear optical response with favorable optical gain performance. As the number of fluorene repeat units in each arm is increased from 3 to 6, these molecules demonstrate a two-photon absorption cross-section as high as 2200 GM, which is comparable to that of linear conjugated polymers. Tailored truxene oligomers with six fluorene units in each arm (T6) show two-photon absorption pumped amplified spontaneous emission with a threshold as low as 2.43 mJ/cm2, which is better than that of the lowest reported threshold in organic semiconductors. Furthermore, we show a frequency up-converted laser using the newly designed and synthesized star-shaped oligomer T6 with a threshold as low as 3.1 mJ/cm2, which is more than an order of magnitude lower than that of any conjugated polymer. Thus, these oligomers with enhanced nonlinear optical properties are highly attractive for bio-integrated applications such as photodynamic therapy and in-vivo bio-sensing

    Synthesis and properties of novel star-shaped oligofluorene conjugated systems with BODIPY cores

    Get PDF
    Star-shaped conjugated systems with varying oligofluorene arm length and substitution patterns of the central BODIPY core have been synthesised, leading to two families of compounds, T-B1–T-B4 and Y-B1–Y-B4, with T- and Y-shaped motifs, respectively. Thermal stability, cyclic voltammetry, absorption and photoluminescence spectroscopy of each member of these two families were studied in order to determine their suitability as emissive materials in photonic applications

    Characterization and Structure of a Zn2+ and [2Fe-2S]-containing Copper Chaperone from Archaeoglobus Fulgidus

    Get PDF
    Bacterial CopZ proteins deliver copper to P1B-type Cu+-ATPases that are homologous to the human Wilson and Menkes disease proteins. The genome of the hyperthermophile Archaeoglobus fulgidus encodes a putative CopZ copper chaperone that contains an unusual cysteine rich N-terminal domain of 130 amino acids in addition to a C-terminal copper-binding domain with a conserved CXXC motif. The N-terminal domain (CopZ-NT) is homologous to proteins found only in extremophiles and is the only such protein that is fused to a copper chaperone. Surprisingly, optical, electron paramagnetic resonance, and X-ray absorption spectroscopic data indicate the presence of a [2Fe-2S] cluster in CopZ-NT. The intact CopZ protein binds two copper ions, one in each domain. The 1.8 Ă… resolution crystal structure of CopZ-NT reveals that the [2Fe-2S] cluster is housed within a novel fold and that the protein also binds a zinc ion at a four cysteine site. CopZ can deliver Cu+ to the A. fulgidus CopA N-terminal metal binding domain and is capable of reducing Cu2+ to Cu+. This unique fusion of a redox-active domain with a CXXC-containing copper chaperone domain is relevant to the evolution of copper homeostatic mechanisms and suggests new models for copper trafficking

    Lipid profile improvement in virologically suppressed hiv-1-infected patients switched to dolutegravir/ abacavir/lamivudine: Data from the SCOLTA project

    Get PDF
    open13noIntroduction: Metabolic disorders are common amongst HIV-infected patients. Data from real-life setting on the impact of DTG/ABC/3TC in virologically suppressed HIV-infected patients are scarce. Methods: We investigated the modification of metabolic profile including fasting glucose, lipid profile and markers of insulin resistance (IR) in experienced patients switching from a boosted protease inhibitors (bPI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen to DTG/ABC/3TC in a prospective, observational, multicenter study. Results: We enrolled 131 HIV-infected patients, of whom 91 (69.5%) males, mean age was 50.5±10.6 years. CDC stage was A in 66 (50.4%) patients, of whom 91 (69.5%) had acquired HIV through sexual contacts. The previous regimen was bPI-based in 79 patients (60.3%) and NNRTI-based in 52 (39.7%). Patients switching from NNRTI showed a significant reduction at week 24 in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL). Triglycerides/high-density lipoprotein cholesterol (TG/HDL) ratio, HDL, median TG and TG/HDL ratio did not show significant modification during follow-up times. Among patients switching from a bPI, we observed a significant reduction in TC and LDL at both follow-up times and a slight increase in HDL. Triglycerides/HDL ratio, median TG and TG/HDL ratio showed a decrease over time that became significant at weeks 24 and 48. Blood glucose levels did not significantly vary during the observation period in patients switching from both bPI and NNRTI-based regimens. Conclusion: Our data suggest an improvement in lipid profile and TG/HDL ratio in pretreated HIV-1-infected patients who switched to DTG/ABC/3TC over 48 weeks, especially in those previously receiving a bPI-based regimen.openBagella P.; Squillace N.; Ricci E.; Gulminetti R.; De Socio G.V.; Taramasso L.; Pellicano G.; Menzaghi B.; Celesia B.M.; Dentone C.; Orofino G.; Bonfanti P.; Madeddu G.Bagella, P.; Squillace, N.; Ricci, Elena; Gulminetti, R.; De Socio, G. V.; Taramasso, L.; Pellicano, G.; Menzaghi, B.; Celesia, B. M.; Dentone, C.; Orofino, G.; Bonfanti, P.; Madeddu, G

    Safety and tolerability of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Disoproxil fumarate in a real life setting: Data from surveillance cohort long-term toxicity antiretrovirals/antivirals (SCOLTA) project.

    Get PDF
    OBJECTIVES: The study aim was to evaluate the impact on Liver and Kidney toxicity of the single tablet regimen Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Disoproxil Fumarate (EVG/COBI/FTC/TDF) on Antiretroviral Therapy (ART) experienced or na\uefve patients. METHODS: Patients initiating EVG/COBI/FTC/TDF were enrolled in the SCOLTA project, a multicenter observational study reporting grade 3-4 Adverse Events in subjects beginning new antiretroviral drug regimens. In this analysis, patients were evaluated at T0 (baseline), T1 (six months) and at T2 (twelve months). RESULTS: A total of 329 patients were enrolled, and 280 (85.1%) of these had at least one follow-up visit. Median observation time was 11 months (IQR 7.0-15.5). Two hundred and two patients (72.1%) were ART experienced and 78 (27.9%) ART naive. Prevalence of HCV-co-infection was 21.4%. At T1, we observed a significant decline in estimated glomerular filtration rate (eGFR), both in experienced and naive patients (mean change from T0-7.5 \ub1 12.8 ml/min, -15.5 \ub1 17.8 ml/min, respectively, p = 0.0005), which was confirmed at T2 (mean change from T0-8.2 \ub1 15.8 ml/min, -17.6 \ub1 19.4 ml/min, respectively, p = 0.001). Regarding aspartate aminotransferase (AST) and alanine transaminase (ALT) grade 1-2 modifications, no significant differences were observed between experienced and na\uefve subjects, but an increased prevalence of abnormal liver function test was observed in patients with chronic HCV infection (p<0.001). CONCLUSIONS: A significant decline in eGFR was observed in patients initiating EVG/COBI/FTC/TDF in the first 6 months, with no significant worsening occurring at 12 months vs. 6 months of therapy. Patients with chronic HCV infection were at higher risk to develop abnormal liver tests
    • …
    corecore