526 research outputs found
Orientation of dichroic dyes in ultra-drawn polyethylenes
The excellent solid-state drawing characteristics of linear polyethylenes were exploited for the orientation of dichroic dyes. Polarizers with high transparency and high level of optical anisotropy were produced from the drawn films contg. anthraquinone or azo dyes. [on SciFinder (R)
Cranial ultrasound findings in preterm germinal matrix haemorrhage, sequelae and outcome
Germinal matrix-intraventricular haemorrhage (GMH-IVH), periventricular haemorrhagic infarction (PHI) and its complication, post-haemorrhagic ventricular dilatation (PHVD), are still common neonatal morbidities in preterm infants that are highly associated with adverse neurodevelopmental outcome. Typical cranial ultrasound (CUS) findings of GMH-IVH, PHI and PHVD, their anatomical substrates and underlying mechanisms are discussed in this paper. Furthermore, we propose a detailed descriptive classification of GMH-IVH and PHI that may improve quality of CUS reporting and prediction of outcome in infants suffering from GMH-IVH/PHI
The Antifungal Plant Defensin HsAFP1 from Heuchera sanguinea Induces Apoptosis in Candida albicans
Plant defensins are active against plant and human pathogenic fungi (such as Candida albicans) and baker's yeast. However, they are non-toxic to human cells, providing a possible source for treatment of fungal infections. In this study, we characterized the mode of action of the antifungal plant defensin HsAFP1 from coral bells by screening the Saccharomyces cerevisiae deletion mutant library for mutants with altered HsAFP1 sensitivity and verified the obtained genetic data by biochemical assays in S. cerevisiae and C. albicans. We identified 84 genes, which when deleted conferred at least fourfold hypersensitivity or resistance to HsAFP1. A considerable part of these genes were found to be implicated in mitochondrial functionality. In line, sodium azide, which blocks the respiratory electron transport chain, antagonized HsAFP1 antifungal activity, suggesting that a functional respiratory chain is indispensable for HsAFP1 antifungal action. Since mitochondria are the main source of cellular reactive oxygen species (ROS), we investigated the ROS-inducing nature of HsAFP1. We showed that HsAFP1 treatment of C. albicans resulted in ROS accumulation. As ROS accumulation is one of the phenotypic markers of apoptosis in yeast, we could further demonstrate that HsAFP1 induced apoptosis in C. albicans. These data provide novel mechanistic insights in the mode of action of a plant defensin
Low-energy dipole excitations towards the proton drip-line: doubly magic 48Ni
The properties of the low-energy dipole response are investigated for the
proton-rich doubly magic nucleus Ni, in a comparative study of two
microscopic models: fully self-consistent Relativistic Random-Phase
Approximation(RRPA) based on the novel density-dependent meson-exchange
interactions, and Continuum Random-Phase Approximation(CRPA) using Skyrme-type
interactions with the continuum properly included. Both models predict the
existence of the low-energy soft mode, i.e. the proton pygmy dipole resonance
(PDR), for which the transition densities and RPA amplitudes indicate the
dynamics of loosely bound protons vibrating against the rest of the nucleons.
The CRPA analysis indicates that the escape width for the proton PDR is rather
large, as a result of the coupling to the continuum.Comment: 12 pages, 3 figures, accepted for publication in Phys. Lett.
Search for the electric dipole excitations to the multiplet in Sn
The odd-mass Sn nucleus was investigated in nuclear resonance
fluorescence experiments up to an endpoint energy of the incident photon
spectrum of 4.1 MeV at the bremsstrahlung facility of the Stuttgart University.
More than 50 mainly hitherto unknown levels were found. From the measurement of
the scattering cross sections model independent absolute electric dipole
excitation strengths were extracted. The measured angular distributions
suggested the spins of 11 excited levels. Quasi-particle phonon model
calculations including a complete configuration space were performed for the
first time for a heavy odd-mass spherical nucleus. These calculations give a
clear insight in the fragmentation and distribution of the , , and
excitation strength in the low energy region. It is proven that the
component of the two-phonon quintuplet built on
top of the ground state is strongly fragmented. The theoretical
calculations are consistent with the experimental data.Comment: 10 pages, 5 figure
Precision cutting of glassy polymers: influence of aging on the cutting process
ABSTRACT This paper presents the results of an experimental study on the influence of aging on the cutting mechanics of glassy polymers. Polystyrene (PS), a glassy polymer, typically behaves brittle when subjected to a stress, it can be made ductile by rejuvenation. It was expected that PS would show a different cutting behaviour when it would be aged or rejuvenated. To investigate this two different molecular weight PS grades were used. Both aged and (mechanically) rejuvenated samples were made from each grade and cut. Cutting forces, chip morphology and surface quality were investigated. Although the chips showed no differences in brittleness and ductility, the measured cutting forces indicated that there is a difference between aged and rejuvenated PS. Also an interesting difference in cutting forces between the two PS grades was found. Investigation of the surface quality of the PS samples showed that the aged samples have smoother surfaces than the rejuvenated samples. It can be concluded that aging does have effect on the cutting mechanics and the obtained surface roughness
Nuclear imaging for diagnosing fracture-related infection
Purpose Fracture-related infection (FRI) is a complication of surgical fracture treatment and can be challenging to diagnose. Recent studies show promising results for the use of either FDG-PET/CT or WBC/anti-granulocyte scintigraphy. The purpose of this pictorial essay is to outline recent developments in nuclear imaging techniques to diagnose FRI. Methods The current literature on this topic is reviewed. Additionally, three examples of patients who underwent nuclear imaging as part of their clinical work-up and surgical treatment for FRI are presented. Results Based on recent retrospective studies, FDG-PET/CT (accuracy 0.83) and WBC scintigraphy with SPECT/CT (accuracy 0.92) both have a good diagnostic accuracy for diagnosing fracture-related infection. Nuclear imaging contributes to a correct diagnosis in patients with FRI. Conclusion Retrospective studies show promising results for both FDG-PET/CT and WBC scintigraphy with SPECT/CT in diagnosing FRI. A prospective, multicenter study (IFI trial), directly comparing MRI, FDG-PET/CT, and WBC scintigraphy with SPECT/CT in patients with suspected FRI, is currently in progress
In Vivo Measurement of Cerebral Mitochondrial Metabolism Using Broadband Near Infrared Spectroscopy Following Neonatal Stroke
Neonatal stroke presents with features of encephalopathy and can result in significant morbidity and mortality. We investigated the cerebral metabolic and haemodynamic changes following neonatal stroke in a term infant at 24 h of life. Changes in oxidation state of cytochrome-c-oxidase (oxCCO) concentration were monitored along with changes in oxy- and deoxy- haemoglobin using a new broadband near-infrared spectroscopy (NIRS) system. Repeated transient changes in cerebral haemodynamics and metabolism were noted over a 3-h study period with decrease in oxyhaemoglobin (HbO2), deoxy haemoglobin (HHb) and oxCCO in both cerebral hemispheres without significant changes in systemic observations. A clear asymmetry was noted in the degree of change between the two cerebral hemispheres. Changes in cerebral oxygenation (measured as HbDiff=HbO2-HHb) and cerebral metabolism (measured as oxCCO) were highly coupled on the injured side of the brain
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