1,602 research outputs found

    Altered Parvalbumin-Positive Neuron Distribution in Basal Ganglia of Individuals with Tourette Syndrome

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    The neuropathology of Tourette Syndrome (TS) is poorly characterized. This thesis provides the first quantitative stereologic immunohistochemical study of the basal ganglia in TS. TS is a childhood neuropsychiatric disorder characterized by motor and vocal tics. Previous imaging studies found alterations in caudate (Cd) and putamen (Pt) volumes. To investigate possible alterations in cell populations, postmortem basal ganglia tissue from individuals with TS and normal controls (NC) was analyzed using unbiased stereological techniques. A markedly higher (\u3e160% of control) total neuron number and density was found in the internal segment of the globus pallidus (GPi) of TS (p220% of control) and proportion of these GPi neurons were positive for the calcium-binding protein parvalbumin (PV) in the tissue from TS subjects (p0.025). The imbalance in striatal and GPi inhibitory neuron distribution suggests that the functional dynamics of cortico-striato-thalamic circuitry are fundamentally altered in severe, persistent TS

    Dichterbij de dagelijkse praktijk? Evaluatieonderzoek naar het inzetten van mystery guest als instrument van toezicht in de ouderenzorg

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    Het afgelopen jaar is door de Inspectie voor de Gezondheidszorg (IGZ) ervaring opgedaan met het inzetten van mystery guests in de intramurale ouderenzorg. Om inzicht te krijgen in de ervaringen met het inzetten van mystery guests als methode van toezicht en in de kwaliteit en bruikbaarheid van de informatie die deze methode oplevert, is in het voorjaar en de zomer van 2012 een inventariserend onderzoek uitgevoerd door het instituut Beleid en Management Gezondheidszorg (iBMG) van de Erasmus Universiteit Rotterdam. Tijdens het onderzoek is gebruik gemaakt van verschillende kwalitatieve onderzoeksmethoden, te weten literatuurstudie, documentenanalyse, webstudie en interviews. In dit rapport bespreken we eerst de context waarin het project zich afspeelt. Specifiek bespreken wij drie factoren die ertoe hebben geleid dat de mystery guests relatief snel zijn ingevoerd als methode van toezicht in de ouderenzorg: (1) de bestuurlijke en maatschappelijke discussie over toezicht op de ouderenzorg, (2) de oproep vanuit de politiek op de IGZ om strenger toezicht uit te voeren en (3) een flexibele definitie van mystery guests. Vervolgens geven we een overzicht van ervaringen met het inzetten van mystery guests (en verwante methoden) als instrument van toezicht in andere toezichtsectoren en elders in de gezondheidszorg. Een belangrijke vraag die hierbij naar voren komt is waar de grens ligt tussen effectief toezicht en “uitlokking”. Dit probleem heeft de IGZ in de praktijk grotendeels kunnen omzeilen door een onafhankelijk bureau in te huren en deze de ruimte te geven de mystery guest bezoeken zelf in te richten

    A toolbox for parameter-free predictions of solid-state properties of monodisperse glassy polymers with frozen-in molecular orientation

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    A toolbox that allows designers to predict the properties of oriented glassy polymers using only existing material constants is constructed from a constitutive model applicable to both polymer solids and polymer melts. Two solid-state properties of practical engineering interest are considered: optical birefringence, and craze initiation stress. Predictions from the toolbox are compared to new experimental measurements on well characterized grades of monodisperse polystyrene, and confirm that the toolbox can account for the effect of polymer molecular weight

    Experimental evidence of bandgap structures in the lower jaw of the bottlenose dolphin (tursiops truncatus)

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    Previous studies using the TLM numerical modelling technique have demonstrated the potential existence of bandgap structures within the lower jawbone of the Atlantic Bottlenose dolphin (Tursiops truncatus). The study presented here shows experimental evidence of the existence of these bandgaps within a 2-D structure that mimics the prinnciple dimensions of the lower teeth and jawbone of the Bottlenose dolphin. The bandgap present is due to the tooth structure in the lower jaw forming a periodic array of scattering elements, which results in the formation of an acoustic stop band that is angular dependent

    A steady-state Bi-substrate technique for measurement of the thermal conductivity of ceramic coatings

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    This paper presents a steady-state, bi-substrate technique for measurement of the through-thickness thermal conductivity of ceramic coatings, with a range of specimen thickness and porosity content. The technique is based on establishing unidirectional steady-state heat flow through the sample, sandwiched between a pair of (metallic) substrates with known thermal properties. Comparison between the heat fluxes passing through the two substrates allows a check to be made about the accuracy of the assumption of unidirectional heat flow. The interfacial conductances must be known and these can be estimated by testing samples of different thickness. Measured conductivities are likely to be more accurate if the interfacial conductance is relatively high. This is assisted by the introduction of a thin interfacial layer of a viscous, thermally conductive compound, or thermal pads of some sort, and by maintaining a suitable pressure across the setup. However, if such compounds (pastes) are used, then care must be taken to ensure that it does not enter the specimen via surface-connected pores, since this could significantly affect the measured conductivity. The reliability of the technique has been confirmed by testing fused silica samples of known thermal conductivity. It has also been applied to sprayed zirconia and plasma electrolytic oxide (PEO) alumina coatings. The values obtained were 1.05±0.10 W m?1 K?1 and 1.63±0.35 W m?1 K?1, respectively

    Role of microenvironment in the mixed Langmuir-Blodgett films

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    This paper reports the pi-A isotherms and spectroscopic characteristics of mixed Langmuir and Langmuir-Blodgett (LB) films of non-amphiphilic carbazole (CA) molecules mixed with polymethyl methacrylate (PMMA) and stearic acid (SA). pi-A isotherm studies of mixed monolayer and as well as also the collapse pressure study of isotherms definitely conclude that CA is incorporated into PMMA and SA matrices. However CA is stacked in the PMMA/SA chains and forms microcrystalline aggregates as is evidenced from the scanning electron micrograph picture. Nature of these aggregated species in the mixed LB films has been revealed by UV-Vis absorption and fluorescence spectroscopic studies. The presence of two different kinds of band systems in the fluorescence spectra of the mixed LB films have been observed. This may be due to the formation of low dimensional aggregates in the mixed LB films. Intensity distribution of different band system is highly sensitive to the microenvironment of two different matrices as well as also on the film thicknessComment: 11 pages, 5 figure

    Geochemical evidence of Milankovitch cycles in Atlantic Ocean ferromanganese crusts

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    Hydrogenetic ferromanganese crusts are considered a faithful record of the isotopic composition of seawater influenced by weathering processes of continental masses. Given their ubiquitous presence in all oceans of the planet at depths of 400–7000 meters, they form one of the most well-distributed and accessible records of water-mass mixing and climate. However, their slow accumulation rate and poor age constraints have to date limited their use to explore 100 ka paleoclimatic phenomena. Here it is shown how the Pb isotope signature and major element content of a Fe-Mn crust from the north-east Atlantic responded to changes in the intensity and geographic extent of monsoonal rainfall over West Africa, as controlled by climatic precession during the Paleocene. The studied high-spatial resolution (4 ÎŒm) laser-ablation multi-collector inductively coupled plasma mass spectrometer (LA-MC-ICP-MS) Pb isotope data is a nearly 2 order of magnitude improvement in spatial and temporal resolution compared to micro-drill subsamples. The record demonstrates cyclicity of the 206Pb/204Pb and 208, 207Pb/206Pb ratios at the scale of single Fe-Mn oxide laminae, in conjunction with variations in the Fe/Mn ratio, Al, Si and Ti content. Time-frequency analysis and astronomical tuning of the Pb isotope data demonstrates the imprint of climatic precession (∌20 ka) modulated by eccentricity (∌100 and 405 ka), yielding growth rates of 1.5–3.5 mm/Ma consistent with previous chemostratigraphic age models. In this context, boreal summer at the perihelion causes stronger insolation over West Africa, resulting in more intense and geographically extended monsoonal rainfalls compared to aphelion boreal summer conditions. This, in turn, influences the balance between the weathering endmembers feeding the north-east Atlantic basin. These results provide a new approach for calibrating Fe-Mn crust records to astronomical solutions, and allow their isotopic and chemical archive to be exploited with an improved temporal resolution of 1000–5000 years

    Immobilization of single strand DNA on solid substrate

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    Thin films based on Layer-by-Layer (LbL) self assembled technique are useful for immobilization of DNA onto solid support. This communication reports the immobilization of DNA onto a solid support by electrostatic interaction with a polycation Poly (allylamine hydrochloride) (PAH). UV-Vis absorption and steady state fluorescence spectroscopic studies exhibit the characteristics of DNA organized in LbL films. The most significant observation is that single strand DNA are immobilized on the PAH backbone of LbL films when the films are fabricated above the melting temperature of DNA. DNA immobilized in this way on LbL films remains as such when the temperature is restored at room temperature and the organization remains unaffected even after several days. UV-Vis absorption spectroscopic studies confirm this finding.Comment: Eight pages, five figure

    Temporal and spectral characteristics of a marine piling operation in shallow water

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    Analysis of the underwater radiate acoustic characteristics for marine piling operations for two pile diameters, 2m and 4.74m, in a relatively shallow water site are presented. Measurements of the entire piling sequence for several piles were conducted at ranges from 10m to 22km for piles in 10-20 m water depth. Variations in the temporal and spectral characteristics of radiated energy are analysed in context of pile size, range from source, hammer energy used and pile penetration depth. Analysis of hammer energy used shows a strong interdependence between mechanical strike ‘hammer’ energy and underwater radiated acoustic energy. This process appears ‘coarsely’ linear for individual piling operations although considerable variation in overall gradient were observed between operations. For individual hammer energy step increases often the largest increases in radiated energy were observed at the initial hammer energy increase, with subsequent strikes at the same hammer energy resulting in a gradual reduction in radiated energy to a level 1-2 dB lower. These effects are potentially due to sediment compacting / relaxation effects relating to the time and number of strikes and penetration. Temporal and spectral variations in radiated energy due to pile penetration are also examined for fixed hammer energy and range. Simultaneous recordings of radiated energy made at increasing distances from the pile showed evidence of temporal and spectral dispersion effects consistent with relatively shallow water propagation. Correlation of received levels at various ranges in differing seabed topographies were made suggesting complex shallow water modal propagation dependant on both the source and environment characteristics including seabed topography, sediment type and water column acoustic properties

    Analytic approximation and an improved method for computing the stress-energy of quantized scalar fields in Robertson-Walker spacetimes

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    An improved method is given for the computation of the stress-energy tensor of a quantized scalar field using adiabatic regularization. The method works for fields with arbitrary mass and curvature coupling in Robertson-Walker spacetimes and is particularly useful for spacetimes with compact spatial sections. For massless fields it yields an analytic approximation for the stress-energy tensor that is similar in nature to those obtained previously for massless fields in static spacetimes.Comment: RevTeX, 8 pages, no figure
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