1,608 research outputs found
Altered Parvalbumin-Positive Neuron Distribution in Basal Ganglia of Individuals with Tourette Syndrome
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
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 âuitlokkingâ. 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
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)
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
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
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
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 400â7000 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 (âŒ20 ka) modulated by eccentricity (âŒ100 and 405 ka), yielding growth rates of 1.5â3.5 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 1000â5000 years
Immobilization of single strand DNA on solid substrate
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
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 âhammerâ energy and underwater radiated acoustic energy. This process appears âcoarselyâ 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
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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