191 research outputs found
Predictors and patterns of red blood cell transfusion use among newly diagnosed cancer patients with chemotherapy-associated anemia in Western Denmark (1998–2003)
Flying doughnut terahertz pulses generated from semiconductor currents
The ability to manipulate the space-time structure of light waves diversifies
light-matter interaction and light-driven applications. Conventionally,
metasurfaces are employed to locally control the amplitude and phase of light
fields by the material response and structure of small meta-atoms. However, the
fixed spatial structures of metasurfaces offer limited opportunities. Here,
using quantum control we introduce a new approach that enables the amplitude,
sign, and even configuration of the generated light fields to be manipulated in
an all-optical manner. Following this approach, we demonstrate the generation
of flying doughnut terahertz (THz) pulses. We show that the single-cycle THz
pulse radiated from the dynamic semiconductor ring current has an electric
field structure that is azimuthally polarized and that the space- and
time-resolved magnetic field has a strong, isolated longitudinal component. As
a first application, we detect absorption features from ambient water vapor on
the spatiotemporal structure of the measured electric fields and the calculated
magnetic fields. Quantum control is a powerful and flexible route to generating
any structured light pulse in the THz range, while pulse compression of
cylindrical vector beams is available for very high-power magnetic-pulse
generation from the mid-infrared to near UV spectral region. Pulses such as
these will serve as unique probes for spectroscopy, imaging,
telecommunications, and magnetic materials
Neuronal precursor cell proliferation in the hippocampus after transient cerebral ischemia: a comparative study of two rat strains using stereological tools
BACKGROUND: We are currently investigating microglial activation and neuronal precursor cell (NPC) proliferation after transient middle cerebral artery occlusion (tMCAo) in rats. This study aimed: (1) to investigate differences in hippocampal NPC proliferation in outbred male spontaneously hypertensive rats (SHRs) and Sprague-Dawley rats (SDs) one week after tMCAo; (2) to present the practical use of the optical fractionator and 2D nucleator in stereological brain tissue analyses; and (3) to report our experiences with an intraluminal tMCAo model where the occluding filament is advanced 22 mm beyond the carotid bifurcation and the common carotid artery is clamped during tMCAo. METHODS: Twenty-three SDs and twenty SHRs were randomized into four groups subjected to 90 minutes tMCAo or sham. BrdU (50 mg/kg) was administered intraperitoneally twice daily on Day 4 to 7 after surgery. On Day 8 all animals were euthanized. NeuN-stained tissue sections were used for brain and infarct volume estimation with the 2D nucleator and Cavalieri principle. Brains were studied for the presence of activated microglia (ED-1) and hippocampal BrdU incorporation using the optical fractionator. RESULTS: We found no significant difference or increase in post-ischemic NPC proliferation between the two strains. However, the response to remote ischemia may differ between SDs and SHRs. In three animals increased post-stroke NPC proliferation was associated with hippocampal ischemic injury. The mean infarct volume was 89.2 ± 76.1 mm(3 )in SHRs and 16.9 ± 22.7 mm(3 )in SDs (p < 0.005). Eight out of eleven SHRs had ischemic neocortical damage in contrast to only one out of 12 SDs. We observed involvement of the anterior choroidal and hypothalamic arteries in several animals from both strains and the anterior cerebral artery in two SHRs. CONCLUSIONS: We found no evidence of an early hippocampal NPC proliferation one week after tMCAo in both strains. Infarction within the anterior choroidal artery could induce hippocampal ischemia and increase NPC proliferation profoundly. NPC proliferation was not aggravated by the presence of activated microglia. Intraluminal tMCAo in SHRs gave a more reliable infarct with neocortical involvement, but affected territories supplied by the anterior cerebral, anterior choroidal and hypothalamic arteries
Induced activation in accelerator components
The residual activity induced in particle accelerators is a serious issue from the point of view of radiation safety as the long-lived radionuclides produced by fast or moderated neutrons and impact protons cause problems of radiation exposure for staff involved in the maintenance work and when decommissioning the facility. This paper presents activation studies of the magnets and collimators in the High Energy Beam Transport line of the European Spallation Source due to the backscattered neutrons from the target and also due to the direct proton interactions and their secondaries. An estimate of the radionuclide inventory and induced activation are predicted using the GEANT4 code
Sustainable Urban Drainage Systems:Using rainwater as a resource to create resilient and liveable cities
Paediatric medical emergency calls to a Danish Emergency Medical Dispatch Centre: a retrospective, observational study
Status Report and Beam Time Request for Experiment AD-4
Summary of current status and plans for October 200
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