Search results for "Role"
showing 10 items of 1994 documents
A Xylochemically Inspired Synthesis of Lamellarin G Trimethyl Ether via an Enaminone Intermediate.
2019
A concise high yielding synthesis of lamellarin G trimethyl ether has been achieved from precursors and solvents that can in principle be derived from xylochemical (woody biomass) sources. The route is comparatively green in that some reactions are performed without solvent or with relatively benign solvents. In addition, chromatographic purification of products is avoided, and only a single aqueous workup is performed. The novelty of the synthesis lies in the intermediacy of an enaminone for the construction of the central pyrrole ring. The overall yield of the product is among the highest reported to date.
Design, Synthesis and Evaluation of Enzyme-Responsive Fluorogenic Probes Based on Pyridine-Flanked Diketopyrrolopyrrole Dyes
2020
The ever-growing demand for fluorogenic dyes usable in the rapid construction of analyte-responsive fluorescent probes, has recently contributed to a revival of interest in the chemistry of diketopyrrolopyrrole (DPP) pigments. In this context, we have explored the potential of symmetrical and unsymmetrical DPP derivatives bearing two or one 4-pyridyl substituents acting as optically tunable group(s). The unique fluorogenic behavior of these molecules, closely linked to N-substitution/charge state of their pyridine unit (i.e., neutral pyridine or cationic pyridinium), has been used to design DPP-based fluorescent probes for detection of hypoxia-related redox enzymes and penicillin G acylase …
Influence of chloride anions on the electrodeposition and electroactivity of the polymer matrix in polypyrrole, poly( N -methylpyrrole) and polypyrro…
2004
We report electrochemical studies on the influence of a small concentration of chloride ions on the electroactivity of the polymer matrix of polypyrrole (PPy), poly(N-methylpyrrole) [p(N-MePy)] and a poly(titanocene-propyl-pyrrole) derivative, p(Tc3Py) [Tc(CH2)3NC4H4; Tc=CpCp′TiCl2; Cp=C5H5; Cp′=C5H4] in acetonitrile (AN), tetrahydrofuran (THF) and N,N-dimethylformamide (DMF). The polymer films were obtained on Pt disc electrodes from AN solutions of the monomers containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF6) as the supporting electrolyte and then transferred to the corresponding monomer-free solution. Studies in Cl−-containing solutions have shown that the p(Tc3Py) matrix…
Electrochemistry, spectroelectrochemistry, chloride binding, and O2 catalytic reactions of free-base porphyrin-cobalt corrole dyads.
2005
Three face-to-face linked porphyrin-corrole dyads were investigated as to their electrochemistry, spectroelectrochemistry, and chloride-binding properties in dichloromethane or benzonitrile. The same three compounds were also investigated as to their ability to catalyze the electroreduction of dioxygen in aqueous 1 M HClO4 or HCl when adsorbed on a graphite electrode. The characterized compounds are represented as (PCY)H2Co, where P = a porphyrin dianion; C = a corrole trianion; and Y = a biphenylenyl, 9,9-dimethylxanthenyl, or anthracenyl spacer, which links the two macrocycles in a face-to-face arrangement. An axial binding of one or two Cl- ligands to the cobalt center of the corrole is …
Methyl vinyl ketone+OH and methacrolein+OH oxidation reactions: a master equation analysis of the pressure- and temperature-dependent rate constants.
2006
High-level electronic structure calculations and master equation analyses were carried out to obtain the pressure- and temperature-dependent rate constants of the methyl vinyl ketone+OH and methacrolein+OH reactions. The balance between the OH addition reactions at the high-pressure limit, the OH addition reactions in the fall-off region, and the pressure-independent hydrogen abstractions involved in these multiwell and multichannel systems, has been shown to be crucial to understand the pressure and temperature dependence of each global reaction. In particular, the fall-off region of the OH addition reactions contributes to the inverse temperature dependence of the rate constants in the Ar…
Immunopathogenesis of atherosclerosis: endotoxin accelerates atherosclerosis in rabbits on hypercholesterolemic diet.
2001
Background—On the basis of our concept that atherosclerosis has an immunopathological background, we tested whether activation of the innate immune system influences its progression.Methods and Results—Hypercholesterolemic (0.5% wt/wt diet) rabbits received either repeated intravenous injections of endotoxin (Escherichia colilipopolysaccharide 1.25 to 2.5 μg, once per week) or a self-limiting cutaneousStaphylococcus aureusinfection with or without a quinolone antibiotic. Measured laboratory parameters, including LDL and HDL cholesterols, were similar in the different groups of hypercholesterolemic animals. All endotoxin-treated animals developed transient episodes of fever after endotoxin a…
Diagnostyka sądowo-kryminalna w orzekaniu i wykonywaniu warunkowego przedterminowego zwolnienia w teorii i praktyce sądowej – raport z badania
2019
Niniejsza praca stanowi podsumowanie projektu badawczego Diagnostyka sądowo-kryminalna w orzekaniu i wykonywaniu warunkowego przedterminowego zwolnienia w teorii i praktyce sądowej, zrealizowanego przez Instytut Wymiaru Sprawiedliwości. Celem projektu, w tym w szczególności przeprowadzonego w jego ramach badania empirycznego, było (m.in.) zweryfi kowanie twierdzenia, w myśl którego w pracy administracji jednostek penitencjarnych oraz sądów penitencjarnych występują niedostatki profesjonalnej i pogłębionej prognozy kryminologicznej. W ramach badania empirycznego przeprowadzono analizę 540 spraw, w których w drugim kwartale 2013 r. pozytywnie rozpatrzono wnioski o udzielenie skazanym warunkow…
Construct Validity of Rizzo et al.'s (1970) Role Conflict and Ambiguity Scales: A Multisample Study
1998
La validite de construction des echelles de Rizzo, House, et Lirtzman (1970) a ete fortement critiquee ces dernieres annees. Les critiques portent sur la formulation des items qui constituent ces echelles, ce qui fait que l'interpretation des echelles depend totalement de la formulation des items. Ces critiques ont favorise l'emergence d'autres modeles factoriels. La duplication elargie de Kelloway et Barling (1990), l'analyse factorielle destinee a confirmer la validite des echelles de Rizzo et al. et une echelle de surcharge des roles avec des items formules a la fois affirmativement et negativement furent utilisees pour eprouver la validite de construction des echelles d'ambiguite et de …
Looking for MACHOs in the Spectra of Fast Radio Bursts
2019
We explore a novel search strategy for dark matter in the form of massive compact halo objects (MACHOs) such as primordial black holes or dense mini-halos in the mass range from $10^{-4}$ to 0.1 solar masses. These objects can gravitationally lens the signal of fast radio bursts (FRBs), producing a characteristic interference pattern in the frequency spectrum, similar to the previously studied femtolensing signal in gamma ray burst spectra. Unlike traditional searches using microlensing, FRB lensing will probe the abundance of MACHOs at cosmological distance scales (~Gpc) rather than just their distribution in the neighborhood of the Milky Way. The method is thus particularly relevant for d…
Gravitational Lensing: the Structure of Quasars and Galaxies
2016
We use gravitational lens systems in which a galaxy produces multiple images of a distant quasar to study the properties of both the unresolved structure of the lensed quasar and the mass distribution in the gravitational lens. First, we estimate the size and the logarithmic slope of the temperature profile in the accretion disk of the lensed quasar Q2237+0305 using a method that is independent of the component velocities, based on six epochs of multi-wavelength narrowband images from the Nordic Optical Telescope. A statistical comparison of the observed microlensing with simulations based on microlensing magnification maps gives Bayesian estimates for the half-light radius of ~8 light-days…