2,871 research outputs found
Use of flow cytometry as a tool to study mitochondrial membrane potential in isolated, living hepatocytes
No full textThe present paper describes the possibility of determination of mitochondrial membrane potential (Delta omega) in isolated hepatocytes making use of a Delta psi-sensitive dye, i.e., the lipophilic cationic probe 5,5'6,6'-tetrachloro-1,1'3,3 '-tetraethylbenzimidazolcarbocyanine iodide (JC-1) and of cytofluorimetry. The validity of the method was proved by treating hepatocytes with FCCP (decrease of Delta psi) and subsequent addition of 6-ketocholestanol (increase of Delta psi). The results indicate that the proposed method may be used in laboratory practice
Effect of cardiolipin on functional properties of isolated rat liver mitochondria
No full textThe specific involvement of cardiolipin in modulating and/or controlling the activity of a number of mitochondrial carriers, enzymes and receptors is well documented; however, comparatively less understood is its role for the integrated functions of intact mitochondria. The aim of the present research was to get a better insight into this problem by investigating the effect of in vitro addition of cardiolipin on the properties of isolated liver mitochondria. The results obtained show that cardiolipin induces extensive structural and functional perturbations at the level of the inner mitochondrial membrane. In fact, addition of cardiolipin to intact mitochondria causes a significant increase of proton leak associated with a parallel increase of respiratory rate in State 4. Concomitantly, a slight uncoupling of phosphorylation associated with a moderate increase in ATPase activity is observed. Furthermore, the pore-mediated membrane permeability to calcium is drastically modified, an effect that can be reversed by addition of cyclosporin
Decrease in mitochondrial energy couplings by thyroid hormones: a physiological effect rather than a pathological hyperthyroidism consequence
No full textThe effect of the in vivo thyroid status on mitochondrial membrane potential (Delta Psi(m)) in isolated rat hepatocytes was studies by means of a cytofluorimetric technique and the Delta Psi(m)-specific probe JC-1. It is shown that the Delta Psi(m) level decreases in the order hypothyroid > euthyroid > hyperthyroid, Polarographic measurement of the hepatocyte respiratory rates revealed an opposite trend of values: the highest respiratory rate in hepatocytes from hyperthyroid animals, the lowest in those from hypothyroid ones. This means that mitochondrial energy coupling is highest in hypothyroid hepatocytes and lowest in hyperthyroid hepatocytes. 6-Ketocholestanol added to hepatocytes failed to counterbalance the uncoupling effect of thyroid hormones on Delta Psi(m) and respiration rate. Under the same conditions, 6-ketocholestanol appeared to be effective in recoupling of respiration uncoupled by low concentrations of the artificial protonophore FCCP, The mechanism and possible physiological functions of the thyroid hormone-induced decrease in mitochondrial energy coupling are discussed. (C) 1998 Federation of European Biochemical Societies
Tangle-bearing neurons survive despite disruption of membrane integrity in a mouse model of tauopathy
No full textNeurofibrillary tangles (NFTs) are associated with neuronal loss and correlate with cognitive impairment in Alzheimer disease, but how NFTs relate to neuronal death is not clear. We studied cell death in Tg4510 mice that reversibly express P301L mutant human tau and accumulate NFTs using in vivo multiphoton imaging of neurofibrillary pathology, propidium iodide (PI) incorporation into cells, caspase activation, and DNA labeling. We first observed that in live mice, a minority of neurons were labeled with the caspase probe or with PI fluorescence. These markers of cell stress were localized in the same cells and appeared specifically within NFT-bearing neurons. Contrary to expectations, the PI-stained neurons did not die during a day of observation; the presence of Hoechst-positive nuclei in them on the subsequent day indicated that the NFT-associated membrane disruption, as suggested by PI staining, and caspase activation do not lead to immediate death of neurons in this tauopathy model. This unique combination of in vivo multiphoton imaging with markers of cell death and pathological alteration is a powerful tool for investigating neuronal damage associated with neurofibrillary pathology
The charge transfer and ion formation in liquid Li-Tl alloys
No full textThe 7Li NMR Knight shift, K, and the spin-lattice relaxation time, T1, were measured for liquid Li–Tl alloys. The K decreases rapidly with the addition of Tl up to 20 at.% Tl. In the concentration from 20 to 50 at.% Tl, the K decreases only slightly and the K of 50 at.% Tl is 60% of K for the pure liquid Li. Such a decrease of K is considered as an indication for the strong charge transfer from Li to Tl. These tendencies are similar to those from previous studies for liquid Li–Ga and Li–In alloys. However, beyond 50 at.% Tl, the K increases and reaches to an almost constant value (70% of K for the pure liquid Li). Such a back donation of charge is absent for liquid Li–Ga and Li–In alloys. It is considered that the tendency of the formation of ionic structural unit for liquid Li–Tl alloys is slightly weaker compared with the cases of liquid Li–Ga and Li–In alloys. The T1 is also discussed with the relation to the Knight shift and the electronic properties
THE VISIBLE EMISSION SPECTRA OF Zn , Cd , Zn Tl, AND Cd Tl MOLECULES
No full textAuthor Institution: Department of Physics, Indian Institute of Technology; Department of Physics, State University of New York at BuffaloNew Spectra have been obtained for Zn-Tl and Cd-Tl mixtures excited by a high frequency oscillator and studied under a dispersion of 5\AA/mm. Both the mixtures show one system in the red, one in the blue and continuous bands attached to the Tl lines 3775 and 5350 \AA. The red system of Zn-Tl mixture exhibits an isotope effect, which shows Zn as the emitter. The emitter for the red system of Cd-Tl mixture is Cd . The blue systems and continuous bands are due to diatomic ZnTl and CdTl molecules. A vibrational analysis of all these systems, wherever possible has been carried out and the constants determined
TL and OSL properties of beta irradiated Y2O3 nanocrystal
No full textNanocrystalline yttrium oxide (Y2O3) is synthesized by low temperature sol-gel technique and synthesized material is annealed at 900°C. The annealed β-rayed Y2O3 two TL glows with prominent peak at 407 K and weak glow peak at 643 K were observed in all irradiated samples. It is found that TL glow peaks intensity linearly increases with increase in β-dose from 0.813 - 40.625 Gy. The TL kinetic parameters are calculated using glow curve deconvoluted (GCD) method. The TL glows exhibits general order kinetics. Intense optical stimulated luminescence (OSL) is observed in the Y2O3 sample. These material exhibits linearity and reproducibility and hence, it suggests that this material may be used as dosimetric applications. © 2017 Author(s)
Preparation of (R)-2-chloro-1-(m-chlorophenyl)ethanol by Lipozyme TL IM-catalyzed second resolution
No full text(R)-2-Chloro-1-(m-chlorophenyl)ethanol, a precursor of (R)-3-chlorostyrene oxide which is the key chiral intermediate for the preparation of several beta 3-adrenergic receptor agonists was prepared in 40% yield and 99% ee by the Lipozyme TL IM-catalyzed second resolution of the corresponding racemate in the presence of vinyl acetate. (C) 2012 Shi Wen Xia. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved
Crystal Dynamics and Anharmonic Properties of Bi-Pb-Tl Alloys
No full textTitle: Crystal Dynamics and Anharmonic Properties of Bi-Pb-Tl Alloys, Author: Aditya P. Roy, Location: ThodeThe crystal dynamics and anharmonic properties have
been investigated in disordered alloys of Bi-Pb-Tl using slow
neutron spectrometry. Damping of phonons caused by phonon-phonon
interaction and the effect of the force constant
disorder on the lifetime of the phonons have been studied in
the alloys. Measurements of the coefficients of thermal
expansion are reported. An experimental method of determining
the lattice frequency spectra by coherent inelastic scattering
of neutrons from polycrystalline materials is described.ThesisDoctor of Philosophy (PhD
Desde I benandanti a Menocchio. Un juego de paciencia conjetural y contextual (Italia, 1966-1976)
No full textLos juegos de paciencia (Giochi di pazienza), parte del título de este ensayo, es un libro formidable y desconocido para una gran mayoría de lectores hispanoparlantes. En 1975 fue publicado por los historiadores ita-lianos Adriano Prosperi y Carlo Ginzburg en la prestigiosa editorial Einaudi. Amigos de generación y compromiso cívico, ambos nacidos en 1939, están marcados por las lecturas de Quaderni del carcere de Antonio Gramsci y la filosofía de Benedetto Croce, así como también por la literatura de post-guerra de Primo Levi, Carlo Levi, Cesare Pavese e Ítalo Calvino y los recorridos estudiantiles y políticos en la Scuola Normale Superiore di Pisa2. Los Giochi di pazienza. Un seminario sul Beneficio di Cristo (Ginzburg y Prosperi)3 lo redactaron en cierta forma anónima, no identificando los fragmentos escritos por cada uno, salvo por la novedosa, aunque descifrable, indicación que el «autor A» había llegado a la figura de Tullio Crispoldi mediante una investigación acerca del obispo de Verona Gian Matteo Giberti, mientras que el «autor B» conocía a Crispoldi y sus escritos por otros autores –Ginzburg–5. Además, ofrecen otra pista de desciframiento: «uno de nosotros había tenido una formación católica» –Prosperi–. Participaron también en el volumen los estudiantes del seminario. Antes de continuar, hacemos una advertencia. Utilizaremos los Giochi di pazienza desde el ejercicio metodológico propuesto por los autores (azar, conjeturas y falsas pistas), dejando de lado el contenido mismo del volume
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