Fluorosolvatochromism of furanyl- and thiophenyl-substituted acetophenones

A series of para-substituted acetophenones bearing a furanyl or a thiophenyl moiety show a large Stokes-shift, which is a function of various solvent properties. Photophysical properties such as emission lifetime of the compounds have been determined using time-correlated-single photon counting to secure the intrinsic fluorescence behaviour. The solvent dependent position of the UV/Vis emission band [small nu, Greek, tilde]max,em of the compounds has been measured in 26 various solvents. The influence of the solvent on [small nu, Greek, tilde]max,em is of very complex nature and mathematically analysed by multiple square linear solvation energy (LSE)-correlation analysis using Catalán's four-solvent parameter set. Solvent acidity has a strong influence on the bathochromic shift of 2,5-disubstituted furan derivatives compared to the non-5-substituted furan and thiophene derivatives, which show a contrary behaviour. Therefore, the 5-cyanofuranyl-substituted acetophenone derivative is useful as a probe for measuring environmental properties by fluorescence spectroscopy.Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

Análise da implantação do sistema de gestão dos resíduos sólidos recicláveis na Vila das Peças, Guaraqueçaba, Paraná, Brasil

Objectives: Despite successful antiretroviral therapy, people living with HIV (PLWH) may show signs of premature/accentuated aging. We compared established biomarkers of aging in PLWH, appropriately chosen HIV-negative individuals, and blood donors, and explored factors associated with biological age advancement. Design: Cross-sectional analysis of 134 PLWH on suppressive antiretroviral therapy, 79 lifestyle-comparable HIV-negative controls aged 45 years or older from the Co-morBidity in Relation to AIDS (COBRA) cohort, and 35 age-matched blood donors. Methods: Biological age was estimated using a validated algorithm based on 10 biomarkers. Associations between ` age advancement' (biological minus chronological age) and HIV status/ parameters, lifestyle, cytomegalovirus (CMV), hepatitis B (HBV) and hepatitis C virus (HCV) infections were investigated using linear regression. Results: The average (95% CI) age advancement was greater in both HIV-positive [13.2 (11.6-14.9) years] and HIV-negative [5.5 (3.8-7.2) years] COBRA participants compared with blood donors [-7.0 (-4.1 to -9.9) years, both P's< 0.001)], but also in HIV-positive compared with HIV-negative participants (P< 0.001). Chronic HBV, higher anti-CMV IgG titer and CD8 thorn T-cell count were each associated with increased age advancement, independently of HIV-status/ group. Among HIV-positive participants, age advancement was increased by 3.5 (0.1-6.8) years among those with nadir CD4 thorn T-cell count less than 200 cells/ ml and by 0.1 (0.06-0.2) years for each additional month of exposure to saquinavir. Conclusion: Both treated PLWH and lifestyle-comparable HIV-negative individuals show signs of age advancement compared with blood donors, to which persistent CMV, HBV co-infection and CD8(+) T-cell activation may have contributed. Age advancement remained greatest in PLWH and was related to prior immunodeficiency and cumulative saquinavir exposure

Cellular delivery of small interfering RNA by a non-covalently attached cell-penetrating peptide: quantitative analysis of uptake and biological effect

Cell-penetrating peptides (CPPs) have evolved as promising new tools to deliver nucleic acids into cells. So far, the majority of these delivery systems require a covalent linkage between carrier and cargo. To exploit the higher flexibility of a non-covalent strategy, we focused on the characterisation of a novel carrier peptide termed MPGα, which spontaneously forms complexes with nucleic acids. Using a luciferase-targeted small interfering RNA (siRNA) as cargo, we optimised the conditions for MPGα-mediated transfection of mammalian cells. In this system, reporter gene activity could be inhibited up to 90% with an IC(50) value in the sub-nanomolar range. As a key issue, we addressed the cellular uptake mechanism of MPGα/siRNA complexes applying various approaches. First, transfection of HeLa cells with MPGα/siRNA complexes in the presence of several inhibitors of endocytosis showed a significant reduction of the RNA interference (RNAi) effect. Second, confocal laser microscopy revealed a punctual intracellular pattern rather than a diffuse distribution of fluorescently labelled RNA-cargo. These data provide strong evidence of an endocytotic pathway contributing significantly to the uptake of MPGα/siRNA complexes. Finally, we quantified the intracellular number of siRNA molecules after MPGα-mediated transfection. The amount of siRNA required to induce half maximal RNAi was 10 000 molecules per cell. Together, the combination of methods provided allows for a detailed side by side quantitative analysis of cargo internalisation and related biological effects. Thus, the overall efficiency of a given delivery technique as well as the mechanism of uptake can be assessed

Do people living with HIV experience greater age advancement than their HIV-negative counterparts?

Objectives: Despite successful antiretroviral therapy, people living with HIV (PLWH) may show signs of premature/accentuated aging. We compared established biomarkers of aging in PLWH, appropriately chosen HIV-negative individuals, and blood donors, and explored factors associated with biological age advancement. Design: Cross-sectional analysis of 134 PLWH on suppressive antiretroviral therapy, 79 lifestyle-comparable HIV-negative controls aged 45 years or older from the Co-mor- Bidity in Relation to AIDS (COBRA) cohort, and 35 age-matched blood donors. Methods: Biological age was estimated using a validated algorithm based on 10 biomarkers. Associations between ‘age advancement’ (biological minus chronological age) and HIV status/parameters, lifestyle, cytomegalovirus (CMV), hepatitis B (HBV) and hepatitis C virus (HCV) infections were investigated using linear regression. Results: The average (95% CI) age advancement was greater in both HIV-positive [13.2 (11.6–14.9) years] and HIV-negative [5.5 (3.8–7.2) years] COBRA participants compared with blood donors [7.0 (4.1 to 9.9) years, both P’s<0.001)], but also in HIV-positive compared with HIV-negative participants (P<0.001). Chronic HBV, higher anti-CMV IgG titer and CD8þ T-cell count were each associated with increased age advancement, independently of HIV-status/group. Among HIV-positive participants, age advancement was increased by 3.5 (0.1–6.8) years among those with nadir CD4þ T-cell count less than 200 cells/ml and by 0.1 (0.06–0.2) years for each additional month of exposure to saquinavir

Chromophore Arylboronsäureester und ihr Komplexbildungsverhalten gegenüber Lewis-Basen

Die vorliegende Arbeit hat die Synthese und Charakterisierung von chromophoren Arylboronsäureestern mit besonderem Augenmerk auf einer breiten strukturellen Variation zum Inhalt. An dieser Verbindungsklasse wird die Wechselwirkung mit Lewis-Basen tiefgehend untersucht. Die Koordination von Lewis-Basen am Bor-Atom führt zu einer Beeinflussung der elektronischen Eigenschaften des borbasierten Substituenten, wobei der Charakter eines direkt am Bor-Atom gebundenen pi-Elektronensystems von pull zu push-pull geschaltet werden kann. In der vorliegenden Arbeit wird beschrieben, wie geometrische und elektronische Strukturmerkmale von boronsäureesterfunktionalisierten Chromophoren durch die Lewis-Säure-Base-Wechselwirkung am Bor-Atom beeinflusst werden. Die Veränderung von molekularen Eigenschaften wird mit Hilfe der UV/vis-Absorptions- und Fluoreszenzspektroskopie, 1H- und 11B-NMR-Spektroskopie sowie mit röntgendiffraktometrischen Methoden untersucht. Die experimentellen Daten werden durch quantenchemische Berechnungen auf DFT-Niveau unterstützt

The MARK-AGE phenotypic database : Structure and strategy

In the context of the MARK-AGE study, anthropometric, clinical and social data as well as samples of venous blood, buccal mucosal cells and urine were systematically collected from 3337 volunteers. Information from about 500 standardised questions and about 500 analysed biomarkers needed to be documented per individual. On the one hand handling with such a vast amount of data necessitates the use of appropriate informatics tools and the establishment of a database. On the other hand personal information on subjects obtained as a result of such studies has, of course, to be kept confidential, and therefore the investigators must ensure that the subjects' anonymity will be maintained. Such secrecy obligation implies a well-designed and secure system for data storage. In order to fulfil the demands of the MARK-AGE study we established a phenotypic database for storing information on the study subjects by using a doubly coded system.publishe

Kinetics of Electrophilic Alkylations of Barbiturate and Thiobarbiturate Anions

Second-order rate constants (<i>k</i>₂) of the reactions of various barbiturate anions such as the parent barbiturate, 1,3-dimethylbarbiturate, 2-thiobarbiturate, and 1,3-diethyl-2-thiobarbiturate with diarylcarbenium ions and Michael acceptors have been determined in dimethyl sulfoxide solution at 20 °C. The reactivity parameters <i>N</i> and <i>s</i>_N of the barbiturate anions were derived from the linear plots of log <i>k</i>₂ versus the electrophilicity parameters <i>E</i> of these reference electrophiles, according to the linear-free-energy relationship log <i>k</i>₂ (20 °C) = <i>s</i>_N (<i>E</i> + <i>N</i>). Several reactions of these nucleophiles with benzylidenemalononitriles and quinone methides proceeded with reversible formation of the new C–C-bond followed by rate-determining proton shift. No evidence for initial attack of the electrophiles at the enolate oxygens of these nucleophiles was found by the kinetic measurements, in line with quantum chemical DFT calculations, which showed that in all cases C-attack is kinetically and thermodynamically preferred over O-attack. The nucleophilic reactivities of barbiturate anions were compared with those of structurally related carbanions, e.g., Meldrum’s acid and dimedone anions

Fluorosolvatochromism of furanyl- and thiophenyl-substituted acetophenones

A series of para-substituted acetophenones bearing a furanyl or a thiophenyl moiety show a large Stokes-shift, which is a function of various solvent properties. Photophysical properties such as emission lifetime of the compounds have been determined using time-correlated-single photon counting to secure the intrinsic fluorescence behaviour. The solvent dependent position of the UV/Vis emission band [small nu, Greek, tilde]max,em of the compounds has been measured in 26 various solvents. The influence of the solvent on [small nu, Greek, tilde]max,em is of very complex nature and mathematically analysed by multiple square linear solvation energy (LSE)-correlation analysis using Catalán's four-solvent parameter set. Solvent acidity has a strong influence on the bathochromic shift of 2,5-disubstituted furan derivatives compared to the non-5-substituted furan and thiophene derivatives, which show a contrary behaviour. Therefore, the 5-cyanofuranyl-substituted acetophenone derivative is useful as a probe for measuring environmental properties by fluorescence spectroscopy

Impact of Black Silicon on Light- and Elevated Temperature-Induced Degradation in Industrial Passivated Emitter and Rear Cells

| openaire: EC/FP7/307315/EU//SOLARXLight and elevated-temperature induced degradation (LeTID) is currently a severe issue in passivated emitter and rear cells (PERC). In this work, we study the impact of surface texture, especially a black silicon (b-Si) nanostructure, on LeTID in industrial p-type mc-Si PERC. Our results show that during standard LeTID conditions the b-Si cells with atomic-layer-deposited aluminum oxide (AlOx) front surface passivation show no degradation despite the presence of a hydrogen-rich AlOx/SiNx passivation stack on the rear. Furthermore, b-Si solar cells passivated with silicon nitride (SiNx) on the front lose only 1.5 %rel of their initial power conversion efficiency, while the acidic-textured equivalents degrade by nearly 4 %rel under the same conditions. Correspondingly, clear degradation is visible in the IQE of the acidic-textured cells, especially in the ~850–1100 nm wavelength range confirming that the degradation occurs in the bulk, while the IQE remains nearly unaffected in the b-Si cells. The observations are supported by spatially-resolved photoluminescence (PL) maps, which show a clear contrast in the degradation behavior of b-Si and acidic-textured cells, especially in the case of SiNx front surface passivation. The PL maps also suggest that the magnitude of LeTID scales with surface area of the texture, rather than wafer thickness that was recently reported, although the b-Si cells are slightly thinner (140 vs. 165 µm). The results indicate that b-Si has a positive impact on LeTID, and hence, benefits provided by b-Si are not limited only to the excellent optical properties, as commonly understood.Peer reviewe

Do people living with HIV experience greater age advancement than their HIV-negative counterparts?

Objectives: Despite successful antiretroviral (ARV) therapy, people living with HIV (PLWH) may show signs of premature/accentuated aging. We compared established biomarkers of aging in PLWH, appropriately-chosen HIV-negative individuals, and blood donors, and explored factors associated with biological age advancement.Design: Cross-sectional analysis of 134 PLWH on suppressive ARV therapy, 79 lifestyle-comparable HIV-negative controls aged ≥45 years from the Co-morBidity in Relation to AIDS (COBRA) cohort, and 35 age-matched blood donors (BD).Methods: Biological age was estimated using a validated algorithm based on ten biomarkers. Associations between ‘age advancement’ (biological minus chronological age) and HIV status/parameters, lifestyle, cytomegalovirus (CMV), hepatitis B (HBV) and hepatitis C virus (HCV) infections were investigated using linear regression.Results: The average (95% CI) age advancement was greater in both HIV-positive [13.2 (11.6, 14.9) years] and HIV-negative [5.5 (3.8, 7.2) years] COBRA participants compared to BD [-7.0 (-4.1, -9.9) years, both p's + T-cell count were each associated with increased age advancement, independently of HIV-status/group. Among HIV-positive participants, age advancement was increased by 3.5 (0.1, 6.8) years among those with nadir CD4+ Conclusions: Both treated PLWH and lifestyle-comparable HIV-negative individuals show signs of age advancement compared to BD, to which persistent CMV, HBV co-infection and CD8+ T-cell activation may have contributed. Age advancement remained greatest in PLWH and was related to prior immunodeficiency and cumulative saquinavir exposure.publishe