3,051 research outputs found
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
TL plots of the Derbyshire data following data manipulation.
No full text<p>Panels a and b illustrate the effects of incentives to reach targets. Panels c and d model the effects of applying a threshold to the reports. Panel a shows data subjected to an incentive to reach 10 reports a month operating above 5 reports. This model consists of reports being “snapped” to 10 once 5 reports are exceeded. Note the gap in the results beginning near 5, the level variance near 10 and subsequent drop in variance at 10. TL fit (long dashed line) is similar to that obtained from the un-manipulated data. Panel b illustrates the impact of an incentive to reach 75 reports with a width of 35 reports. TL fits show how the manipulation results in an increase in exponent and a decrease in pre-exponential factor. Note the gaps in the results beginning near the lower end of the incentive zone, the flattening of variance between the bottom of the incentive zone and the target value, and subsequent drop in variance at 75. These features give clues about the “strength” of the incentive and the target value. Panels c and d are TL plots for data to which a threshold of 10 crimes must be exceeded before a crime is reported (solid squares and long dashed line) in comparison to the original TL fit (dotted line). The solid lines are the behavior of a Poisson distribution with no gain.</p
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
Plasmonic nanorods provide reversible control over nanostructure of self-assembled drug delivery materials.
No full textThe nanostructure of mesophase liquid crystals prepared from amphiphilic lipids controls the rate of release of incorporated agents from the material, such as drug molecules, and reversible transition between different nanostructures essentially provides an “on−off” switch for release (Fong, W.-K.; Hanley, T.; Boyd, B. J. J. Controlled Release 2009, 135, 218−226). In this study, the incorporation of plasmonic hydrophobized gold nanorods (GNRs) permits reversible manipulation of nanostructure on-demand, by irradiation of the matrix using a near-infrared laser. Synchrotron small-angle X-ray scattering was used to probe the kinetics of the response of nanostructure to laser irradiation, and the specificity of the approach is shown by the lack of response in the absence of nanorods, or for GNR whose dimensions are not matched to the specific wavelength of the incident light. © 2010, American Chemical Societ
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
Synthesis optimization and charge carrier transfer mechanism in LiLuSiO<sub>4</sub>:Ce, Tm storage phosphor
No full textLiLuSiO4:Ce and LiLuSiO4:Ce, Tm show very efficient charge carrier storage properties upon beta irradiation after samples have received treatment in vacuum. They outperform the commercial storage phosphor BaFBr(I):Eu2+ in many aspects. The influence of the synthesis conditions, Ce and Tm concentration, nonstoichiometry and codoping with Ca, Hf, Al and Ge are reported. Based on the results of the synthesis optimization, thermoluminescence (TL) emission and TL excitation spectra a mechanism of charge carrier transfer, storage, and recombination during irradiation and thermal or optical readout is proposed.Accepted Author ManuscriptRST/Fundamental Aspects of Materials and EnergyRST/Luminescence Material
On energy storage of Lu2O3:Tb,M (M=Hf, Ti, Nb) sintered ceramics: Glow curves, dose-response dependence, radiation hardness and self-dose effect
No full textThermoluminescent properties and energy storage characteristics of Lu2O3:Tb,M (M = Hf, Ti, Nb) sintered ceramics induced by ionizing radiation are presented and discussed. Dose-response dependence, radiation hardness and fading are studied. A linearity of the former exceeding seven orders of magnitude is confirmed for Lu2O3:Tb,Hf and Lu2O3:Tb,Nb ceramics. Lu2O3:Tb,Hf shows the best TL performance and also its fading is the lowest reaching 15% over 7 h and shows tendency to saturate. During the same period of time the Lu2O3:Tb,Ti, despite having TL at higher temperatures, losses about 25% of the stored energy and the TL signal of Lu2O3:Tb,Nb fades by almost 40% over 7 h. First order TL kinetics is confirmed for all three compositions. A self-dose effect in Lu2O3:Tb,Hf due to a natural content of the radioactive isotope (2.6%) is proved to be important for long-time reading of low doses.Accepted Author ManuscriptRST/Luminescence Material
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