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A serial SPECT-CT study in a celiac disease patient with cerebellar ataxia and psychiatric symptoms
(2021)
Celiac disease (CD) is an immune-mediated systemic disorder triggered by gluten and related prolamins in genetically predisposed individuals. Here, we described a case of a 31-year-old Caucasian woman who exhibited cerebellar and psychiatric dysfunctions. The patient underwent single-photon emission computed tomography (SPECT-CT) before and after a gluten-free diet (GFD). There was an improvement in cerebellar perfusion accompanied by a remission of cerebellar manifestations. The maintenance of the psychiatric manifestations was related to the persistence of the hypoperfusion in the frontal lobes. The patient's psychiatric symptoms did not change after 4 months under a GFD in the hospital. To our knowledge, this is the first case that shows the relationship between improvement in cerebellar perfusion and remission of cerebellar clinical manifestations in a CD patient under a GFD.
AlGaN/GaN heterostructure field effect transistors (HFETs) were irradiated with 2 MeV protons, carbon, oxygen, iron and krypton ions with fluences ranging from 1 × 109 cm−2 to 1 × 1013 cm−2. DC, pulsed I–V characteristics, loadpull and S-parameters of the AlGaN HFET devices were measured before and after irradiation. In parallel, a thick GaN reference layer was also irradiated with the same ions and was characterized by X-ray diffraction, photoluminescence, Hall measurements before and after irradiation. Small changes in the device performance were observed after irradiation with carbon and oxygen at a fluence of 5 × 1010 cm−2. Remarkable changes in device characteristics were seen at a fluence of 1 × 1012 cm−2 for carbon, oxygen, iron and krypton irradiation. Similarly, remarkable changes were also observed in the GaN layer for irradiations with fluence of 1 × 1012 cm−2. The results found on devices and on the GaN layer were compared and correlated.
AlGaN/GaN heterostructure field effect transistors (HFETs) were irradiated with protons as well as carbon, oxygen, iron and krypton ions of high (68 and 120 MeV) and low (2 MeV) energy with fluences in the range from 1x107 to 1x1013 cm-2. High energy irradiation with protons, carbon and oxygen produced no degradation in devices while krypton irradiation at the fluence of 1x1010 cm-2 resulted in a small reduction of 2% in the transconductance. Similarly, for GaN samples irradiated with protons, carbon and oxygen at high energy no changes were seen by XRD, PL and Hall effect, while changes in lattice constant and a reduction in PL intensity were observed after irradiation with high energy krypton. Low energy irradiation with carbon and oxygen at a fluence of 5x1010 cm-2 results in small change in the device performance while remarkable changes in device characteristics are seen at a fluence of 1x1012 cm-2 for carbon, oxygen, iron and krypton irradiation. Similarly changes are also observed by XRD, PL and Hall effect for the thick GaN layer irradiated at the fluence of 1x1012 cm-2. The device results and GaN layer properties are strongly correlated.
The effect of proton, carbon, oxygen and krypton irradiation on AlGaN HFET devices has been studied. Irradiation was performed at 68 and 120 MeV with fluences in the range from 1 × 10^7 to 1 × 10^13 cm2 . Before and after irradiation, dc and pulsed I – V characteristics, loadpull and S -parameters of the AlGaN HFET devices were measured. A thick GaN reference layer was characterized by x-ray diffraction, photoluminescence and Hall measurements before and after irradiation. Proton, carbon and oxygen irradiation show no degradation in devices while krypton irradiation shows a small change at a fluence of 1 × 10 10 cm2 in the device characteristics. The device results are correlated with the thick GaN results.
Investigating Asymptotic Suction Boundary Layers using a One-Dimensional Stochastic Turbulence Model
(2017)
The turbulent asymptotic suction boundary layer is studied using a
one-dimensional turbulence (ODT) model. ODT is a fully resolved,
unsteady stochastic simulation technique. While flow properties
reside on a one-dimensional domain, turbulent advection is represented
using mapping events whose occurrences are governed
by a random process. Due to its reduced spatial dimensionality,
ODT achieves major cost reductions compared to three-dimensional
(3D) simulations. A comparison to recent direct numerical simulation
(DNS) data at moderate Reynolds number (Re = u∞/v0 = 333, where u∞ and v0 are the free stream and suction velocity, respectively) suggests that theODT model is capable of reproducing several velocity statistics, i.e.mean velocity and turbulent kinetic energy budgets, while peak turbulent stresses are under-estimated by ODT. Variation of the Reynolds number in the range Re ∈ [333, 400, 500, 1000] shows that ODT can reproduce various trends observed as a result of increased suction in turbulent asymptotic suction boundary layers, i.e. the reduction of Reynolds stresses and enhanced skin friction.
While up to Re = 500 our results can be directly compared to recent
LES data, the simulation at Re = 1000 is currently not feasible through full 3D simulations, hence ODTmay assist the design of future DNS or LES simulations at larger Reynolds numbers.
Investigating Asymptotic Suction Boundary Layers using a One-Dimensional Stochastic Turbulence Model
(2017)
Angesichts der immer stärker werdenden Diskussion um die Bedeutung von Gesundheit für den schulischen und außerschulischen Bildungs- und Lernprozess und der Risiken wachsender gesundheitlicher Ungleichheit bei Kindern und Jugendlichen (Hurrelmann/Richter 2013, Lampert et al. 2019) ist die Etablierung eines Studienganges „Gesundheitspädagogik und Gesundheitsdidaktik“ längst überfällig und von besonderer Bedeutung für gesundheitliche Chancengleichheit (Goldfriedrich & Hurrelmann, 2021a; 2021b).
Dieses Konzeptpapier stellt einen Modellstudiengang vor, bei dem insbesondere die Vermittlungsebenen – also die gesundheitsdidaktischen Gegenstandsbereiche – im Vordergrund stehen. Die Ausarbeitungen des Entwurfs basieren auf der Grundlage politischer Bestrebungen, der bisherigen Forschung zur Gesundheitspädagogik und Gesundheitsdidaktik, den Erkenntnissen der Erziehungs- und Gesundheitswissenschaften sowie wissenschaftlichen und interprofessionellen Beiträgen des Netzwerks Gesundheitsdidaktik (bestehend aus 33 Expert*innen aus 24 Fachbereichen).