1,060 research outputs found
SPHERES, J\"ulich's High-Flux Neutron Backscattering Spectrometer at FRM II
SPHERES (SPectrometer with High Energy RESolution) is a third-generation
neutron backscattering spectrometer, located at the 20 MW German neutron source
FRM II and operated by the Juelich Centre for Neutron Science. It offers an
energy resolution (fwhm) better than 0.65 micro-eV, a dynamic range of +-31
micro-eV, and a signal-to-noise ratio of up to 1750:1.Comment: 12 pages, 7 figures, 2 tables. Supplemental material consists of 3
pages, 2 figures, 2 table
CG-SENSE revisited: Results from the first ISMRM reproducibility challenge
Purpose: The aim of this work is to shed light on the issue of
reproducibility in MR image reconstruction in the context of a challenge.
Participants had to recreate the results of "Advances in sensitivity encoding
with arbitrary k-space trajectories" by Pruessmann et al.
Methods: The task of the challenge was to reconstruct radially acquired
multi-coil k-space data (brain/heart) following the method in the original
paper, reproducing its key figures. Results were compared to consolidated
reference implementations created after the challenge, accounting for the two
most common programming languages used in the submissions (Matlab/Python).
Results: Visually, differences between submissions were small. Pixel-wise
differences originated from image orientation, assumed field-of-view or
resolution. The reference implementations were in good agreement, both visually
and in terms of image similarity metrics.
Discussion and Conclusion: While the description level of the published
algorithm enabled participants to reproduce CG-SENSE in general, details of the
implementation varied, e.g., density compensation or Tikhonov regularization.
Implicit assumptions about the data lead to further differences, emphasizing
the importance of sufficient meta-data accompanying open data sets. Defining
reproducibility quantitatively turned out to be non-trivial for this image
reconstruction challenge, in the absence of ground-truth results. Typical
similarity measures like NMSE of SSIM were misled by image intensity scaling
and outlier pixels. Thus, to facilitate reproducibility, researchers are
encouraged to publish code and data alongside the original paper. Future
methodological papers on MR image reconstruction might benefit from the
consolidated reference implementations of CG-SENSE presented here, as a
benchmark for methods comparison.Comment: Submitted to Magnetic Resonance in Medicine; 29 pages with 10 figures
and 1 tabl
Digitalisierung in der Erwachsenenbildung
Aus dem Inhalt: Digitalisierung in der Erwachsenenbildung - zur Einleitung in den Themenschwerpunkt; Erwachsenenbildung in der digitalen Welt: Handlungsebenen der digitalen Transformation; Digitalisierung und Mediatisierung in der Erwachsenenbildung/Weiterbildung; Digitale Lernumwelten in produzierenden Betrieben; Zur Modellierung einer Kultur der Digitalität; Bildungsberatung in Beschäftigung und Weiterbildung im Kontext der Digitalisierung; Best-practice-Beispiele für digitale Weiterbildungsangebote
Multi-scale characterisation of a ferroelectric polymer reveals the emergence of a morphological phase transition driven by temperature
[EN] Ferroelectric materials exhibit a phase transition to a paraelectric state driven by temperature
- called the Curie transition. In conventional ferroelectrics, the Curie transition is caused by a
change in crystal symmetry, while the material itself remains a continuous three-dimensional
solid crystal. However, ferroelectric polymers behave differently. Polymeric materials are
typically of semi-crystalline nature, meaning that they are an intermixture of crystalline and
amorphous regions. Here, we demonstrate that the semi-crystalline morphology of the ferroelectric
copolymer of vinylidene fluoride and trifluoroethylene (P(VDF-TrFE)) strongly
affects its Curie transition, as not only a change in crystal symmetry but also in morphology
occurs. We demonstrate, by high-resolution nanomechanical measurements, that the semicrystalline
microstructure in the paraelectric state is formed by crystalline domains
embedded into a softer amorphous phase. Using in situ X-ray diffraction measurements, we
show that the local electromechanical response of the crystalline domains is counterbalanced
by the amorphous phase, effectively masking its macroscopic effect. Our quantitative multiscale
characterisations unite the nano- and macroscopic material properties of the ferroelectric
polymer P(VDF-TrFE) through its semi-crystalline nature.European Union’s Horizon 2020 research and Innovation programme under the Marie Skłodowska-Curie grant agreement number 721874 (SPM2.0). RG acknowledges funding from the European Research Council ERC–AdG–340177 (3DNanoMech). This work was supported by the UK government’s Department for Business, Energy and Industrial Strategy. The dynamic mechanical analysis was supported by T. Koch from the Institute of Materials Science and Technology, TU Wien. We gratefully thank A. Muhamedagić for the contribution of artworks to the figures (armindesign.li).Peer reviewe
Autonomic modulation and antiarrhythmic therapy in a model of long QT syndrome type 3
AIMS: Clinical observations in patients with long QT syndrome carrying sodium channel mutations (LQT3) suggest that bradycardia caused by parasympathetic stimulation may provoke torsades de pointes (TdP). beta-Adrenoceptor blockers appear less effective in LQT3 than in other forms of the disease. METHODS AND RESULTS: We studied effects of autonomic modulation on arrhythmias in vivo and in vitro and quantified sympathetic innervation by autoradiography in heterozygous mice with a knock-in deletion (DeltaKPQ) in the Scn5a gene coding for the cardiac sodium channel and increased late sodium current (LQT3 mice). Cholinergic stimulation by carbachol provoked bigemini and TdP in freely roaming LQT3 mice. No arrhythmias were provoked by physical stress, mental stress, isoproterenol, or atropine. In isolated, beating hearts, carbachol did not prolong action potentials per se, but caused bradycardia and rate-dependent action potential prolongation. The muscarinic inhibitor AFDX116 prevented effects of carbachol on heart rate and arrhythmias. beta-Adrenoceptor stimulation suppressed arrhythmias, shortened rate-corrected action potential duration, increased rate, and minimized difference in late sodium current between genotypes. beta-Adrenoceptor density was reduced in LQT3 hearts. Acute beta-adrenoceptor blockade by esmolol, propranolol or chronic propranolol in vivo did not suppress arrhythmias. Chronic flecainide pre-treatment prevented arrhythmias (all P < 0.05). CONCLUSION: Cholinergic stimulation provokes arrhythmias in this model of LQT3 by triggering bradycardia. beta-Adrenoceptor density is reduced, and beta-adrenoceptor blockade does not prevent arrhythmias. Sodium channel blockade and beta-adrenoceptor stimulation suppress arrhythmias by shortening repolarization and minimizing difference in late sodium current.status: publishe
New Variant of MELAS Syndrome With Executive Dysfunction, Heteroplasmic Point Mutation in the MT-ND4 Gene (m.12015T>C; p.Leu419Pro) and Comorbid Polyglandular Autoimmune Syndrome Type 2
Background: Mitochondrial diseases are caused by dysfunctions in mitochondrial metabolic pathways. MELAS syndrome is one of the most frequent mitochondrial disorders; it is characterized by encephalopathy, myopathy, lactic acidosis, and stroke-like episodes. Typically, it is associated with a point mutation with an adenine-to-guanine transition at position 3243 of the mitochondrial DNA (mtDNA; m.3243A>G) in the mitochondrially encoded tRNA leucine 1 (MT-TL1) gene. Other point mutations are possible and the association with polyglandular autoimmune syndrome type 2 has not yet been described.Case presentation: We present the case of a 25-year-old female patient with dysexecutive syndrome, muscular fatigue, and continuous headache. Half a year ago, she fought an infection-triggered Addison crisis. As the disease progressed, she had two epileptic seizures and stroke-like episodes with hemiparesis on the right side. Cerebral magnetic resonance imaging showed a substance defect of the parieto-occipital left side exceeding the vascular territories with a lactate peak. The lactate ischemia test was clearly positive, and a muscle biopsy showed single cytochrome c oxidase-negative muscle fibers. Genetic testing of blood mtDNA revealed a heteroplasmic base exchange mutation in the mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 4 (MT-ND4) gene (m.12015T>C; p.Leu419Pro; heteroplasmy level in blood 12%, in muscle tissue: 15%). The patient suffered from comorbid autoimmune polyglandular syndrome type 2 with Hashimoto's thyroiditis, Addison's disease, and autoimmune gastritis. In addition, we found increased anti-glutamic acid decarboxylase 65, anti-partial cell, anti-intrinsic factor, and anti-nuclear antibodies.Conclusion: We present an atypical case of MELAS syndrome with predominant symptoms of a dysexecutive syndrome, two stroke-like episodes, and fast-onset fatigue. The symptoms were associated with a not yet described base and aminoacid exchange mutation in the MT-ND4 gene (m.12015T>C to p.Leu419Pro). The resulting changed protein complex in our patient is part of the respiratory chain multicomplex I and might be the reason for the mitochondriopathy. However, different simulations for pathogenetic relevance are contradictory and rather speak for a benign variant. To our knowledge this case report is the first reporting MELAS syndrome with comorbid polyglandular autoimmune syndrome type 2. Screening for autoimmune alterations in those patients is important to prevent damage to end organs
Viscum album L. extracts in breast and gynaecological cancers: a systematic review of clinical and preclinical research
<p>Abstract</p> <p>Background</p> <p><it>Viscum album </it>L. extracts (VAE, European mistletoe) are a widely used medicinal plant extract in gynaecological and breast-cancer treatment.</p> <p>Methods</p> <p>Systematic review to evaluate clinical studies and preclinical research on the therapeutic effectiveness and biological effects of VAE on gynaecological and breast cancer. Search of databases, reference lists and expert consultations. Criteria-based assessment of methodological study quality.</p> <p>Results</p> <p>19 randomized (RCT), 16 non-randomized (non-RCT) controlled studies, and 11 single-arm cohort studies were identified that investigated VAE treatment of breast or gynaecological cancer. They included 2420, 6399 and 1130 patients respectively. 8 RCTs and 8 non-RCTs were embedded in the same large epidemiological cohort study. 9 RCTs and 13 non-RCTs assessed survival; 12 reported a statistically significant benefit, the others either a trend or no difference. 3 RCTs and 6 non-RCTs assessed tumour behaviour (remission or time to relapse); 3 reported statistically significant benefit, the others either a trend, no difference or mixed results. Quality of life (QoL) and tolerability of chemotherapy, radiotherapy or surgery was assessed in 15 RCTs and 9 non-RCTs. 21 reported a statistically significant positive result, the others either a trend, no difference, or mixed results. Methodological quality of the studies differed substantially; some had major limitations, especially RCTs on survival and tumour behaviour had very small sample sizes. Some recent studies, however, especially on QoL were reasonably well conducted. Single-arm cohort studies investigated tumour behaviour, QoL, pharmacokinetics and safety of VAE. Tumour remission was observed after high dosage and local application. VAE application was well tolerated. 34 animal experiments investigated VAE and isolated or recombinant compounds in various breast and gynaecological cancer models in mice and rats. VAE showed increase of survival and tumour remission especially in mice, while application in rats as well as application of VAE compounds had mixed results. <it>In vitro </it>VAE and its compounds have strong cytotoxic effects on cancer cells.</p> <p>Conclusion</p> <p>VAE shows some positive effects in breast and gynaecological cancer. More research into clinical efficacy is warranted.</p
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