The Dzyaloshinskii-Moriya (DM) interaction plays an essential role in novel topological spintronics, and the ability to control this chiral interaction is of key importance. Developing a general ...microscopic framework to compute DM interactions using imaginary-time Green's function formalism, we theoretically show that the ac electric field component of a laser pulse induces nonequilibrium static DM interactions in an antiferromagnetic system in the presence of relativistic spin-orbit coupling. These induced DM interactions might even be anisotropic depending on the direction of magnetic moments and the laser pulse polarization. We further show that intense polarized laser pulses can in principle generate both classes of DM interactions, i.e., bulk-type and interfacial-type, in a magnetic system even though the crystal symmetry prohibits one of them in equilibrium. Our results reveal another aspect of rich behavior of periodically driven spin systems and out of equilibrium magnetic systems.
In order to reduce the prognostically relevant time interval between the initial manifestation of a rheumatic and musculoskeletal disease and diagnosis as well as the consecutive initiation of an ...appropriate treatment, several rheumatological centers in Germany have improved the access to initial rheumatologic evaluation by establishing early recognition/screening clinics at their respective sites. Corresponding models located at Altoetting·Burghausen, Bad Pyrmont, Berlin Buch, Duesseldorf, Heidelberg, Herne, Mannheim as well as supraregional/multicenter initiatives Rheuma Rapid, RhePort and Rheuma-VOR are presented in this overview along with the respective characteristics, potential advantages and disadvantages, but also first evaluation results of several models. The aim of this publication is to promote early detection of rheumatic and musculoskeletal diseases as one of the most important challenges in current rheumatology by encouraging further rheumatologic centers and practices to launch their own early recognition/screening consultation model on the basis of aspects presented herein.
Polyhedral Gauß–Seidel converges Gräser, C.; Sander, O.
Journal of numerical mathematics,
10/2014, Letnik:
22, Številka:
3
Journal Article
Recenzirano
- We prove global convergence of an inexact extended polyhedral Gauß-Seidel method for the minimization of strictly convex functionals that are continuously differentiable on each polyhedron of a ...polyhedral decomposition of their domains of definition. While pure Gauß-Seidel methods are known to be very slow for problems governed by partial differential equations, the presented convergence result also covers multilevel methods that extend the Gauß-Seidel step by coarse level corrections. Our result generalizes the proof of 10 for differentiable functionals on the Gibbs simplex. Example applications are given that require the generality of our approach.
Adherence to surveillance colonoscopy guidelines is important to prevent colorectal cancer (CRC) and unnecessary workload.
To evaluate how well Canadian gastroenterologists adhere to colonoscopy ...surveillance guidelines after adenoma removal or treatment for CRC.
Patients with a history of adenomas or CRC who had surveillance performed between October 2008 and October 2010 were retrospectively included. Time intervals between index colonoscopy and surveillance were compared with the 2008 guideline recommendations of the American Gastroenterological Association and regarded as appropriate when the surveillance interval was within six months of the recommended time interval.
A total of 265 patients were included (52% men; mean age 58 years). Among patients with a normal index colonoscopy (n=110), 42% received surveillance on time, 38% too early (median difference = 1.2 years too early) and 20% too late (median difference = 1.0 year too late). Among patients with nonadvanced adenomas at index (n=96), 25% underwent surveillance on time, 61% too early (median difference = 1.85) and 14% too late (median difference = 1.1). Among patients with advanced neoplasia at index (n=59), 29% underwent surveillance on time, 34% too early (median difference = 1.86) and 37% later than recommended (median difference = 1.61). No significant difference in adenoma detection rates was observed when too early surveillance versus appropriate surveillance (34% versus 33%; P=0.92) and too late surveillance versus appropriate surveillance (21% versus 33%; P=0.11) were compared.
Only a minority of surveillance colonoscopies were performed according to guideline recommendations. Deviation from the guidelines did not improve the adenoma detection rate. Interventions aimed at improving adherence to surveillance guidelines are needed.
Abstract During secondary fracture healing, various tissue types including new bone are formed. The local mechanical strains play an important role in tissue proliferation and differentiation. To ...further our mechanobiological understanding of fracture healing, a precise assessment of local strains is mandatory. Until now, static analyses using Finite Elements (FE) have assumed homogenous material properties. With the recent quantification of both the spatial tissue patterns (Vetter et al., 2010) and the development of elastic modulus of newly formed bone during healing (Manjubala et al., 2009 ), it is now possible to incorporate this heterogeneity. Therefore, the aim of this study is to investigate the effect of this heterogeneity on the strain patterns at six successive healing stages. The input data of the present work stemmed from a comprehensive cross-sectional study of sheep with a tibial osteotomy (Epari et al., 2006 ). In our FE model, each element containing bone was described by a bulk elastic modulus, which depended on both the local area fraction and the local elastic modulus of the bone material. The obtained strains were compared with the results of hypothetical FE models assuming homogeneous material properties. The differences in the spatial distributions of the strains between the heterogeneous and homogeneous FE models were interpreted using a current mechanobiological theory ( Isakson et al., 2006 ). This interpretation showed that considering the heterogeneity of the hard callus is most important at the intermediate stages of healing, when cartilage transforms to bone via endochondral ossification.
Introduction and PurposeRenal involvement impairs the outcome of systemic lupus erythematosus (SLE). Renal biopsy is the gold standard of confirming the diagnosis of lupus nephritis but the ...assessment of reversibility and follow-up remain a challenge. In particular there is a need for non-invasive methods in situations of an unfavourable benefit/risk ratio (e.g., risk of bleeding, suspected minor changes). Non-contrast functional multiparametric MRI (mpMRI) can provide information on morphology, perfusion, and microstructure. Initial studies show changes in renal pathologies.1 Renal T1 mapping shows changes in acute kidney injury, but it also correlates with fibrosis and loss of function in chronic kidney disease.2, 3 The aim of this pilot study was to investigate the feasibility of mpMRI including T1 mapping, the latter not yet described in lupus nephritis.MethodsThe renal mpMRI protocol applied in this study includes techniques for non-contrast assessment of tissue perfusion (Arterial Spin Labeling; ASL), tissue oxygenation (Blood Oxygenation Level Dependent; BOLD) and tissue integrity and structure assessment techniques such as T1 mapping, the apparent diffusion coefficient (ADC) and fractional anisotropy (FA). We compared the renal mpMRI in three affected SLE patients with different states of renal involvement (active vs. former vs. no renal involvement): 1. Active LN IV/V (Creatinine 0.69 mg/dl, Proteinuria 3.2 g/g Creatinine, Erythrocyturia 201/µl, 70% dysmorphic erythrocytes). 2. Former LN III (2011) (2021: Creatinine 1.44 mg/dl, Proteinuria 0.26 g/g Creatinine, Erythrocyturia 26/µl). 3. SLE without evidence of renal involvement (Creatinine 0.77 mg/dl, Proteinuria <0.15 g/g Creatinine, Erythrocyturia 25/µl).ResultsCase 1 (active LN IV/V) shows a decrease in ADC as a possible sign of edema and a reduction in renal blood flow. Tissue oxygenation, as a possible correlate of active inflammation, is clearly increased. Cortical T1 times are strongly increased, which might be caused by edema.Case 2 (former LN III) shows reduced medullary FA as an indication of (chronic) tubular damage. Renal oxygenation is normal. Renal blood flow and ADC are slightly decreased, while T1 times are slightly increased, which might be expression of a fibrotic process.Case 3 (control) also shows reduced medullary FA, while other parameters are normal (figure 1).Abstract PO.5.118 Figure 1mpMRI images of a healthy control, a patient with active LN III and a patient with SLE without evidence of renal involvement. FA (fractional anisotrophy), ADC (apparent diffusion coefficient), ALS (arterial spin labelling), BOLD (blood oxygen level dependent)ConclusionsMultiparametric renal MRI of patients with LN shows differences in renal involvement and between acute and chronic manifestation. First examples of T1 mapping suggest applicability to this condition. Further studies are planned to establish this promising method in diagnosis, prognosis assessment and therapy control of renal involvement in SLE.Referencesdoi: 10.1016/j.mri.2015.06.019. Epub 2015 Jun 25. PMID: 26119419.doi: 10.1007/s00330-017-4943-4. Epub 2017 Jul 14. PMID: 28710580.doi: 10.1093/ndt/gfz129. PMID: 31257440; PMCID: PMC7282828.
During secondary bone healing, different tissue types are formed within the fracture callus depending on the local mechanical and biological environment. Our aim was to understand the temporal ...succession of these tissue patterns for a normal bone healing progression by means of a basic mechanobiological model. The experimental data stemmed from an extensive, previously published animal experiment on sheep with a 3 mm tibial osteotomy. Using recent experimental data, the development of the hard callus was modelled as a porous material with increasing stiffness and decreasing porosity. A basic phenomenological model was employed with a small number of simulation parameters, which allowed comprehensive parameter studies. The model distinguished between the formation of new bone via endochondral and intramembranous ossification. To evaluate the outcome of the computer simulations, the tissue images of the simulations were compared with experimentally derived tissue images for a normal healing progression in sheep. Parameter studies of the threshold values for the regulation of tissue formation were performed, and the source of the biological stimulation (comprising e.g. stem cells) was varied. It was found that the formation of the hard callus could be reproduced in silico for a wide range of threshold values. However, the bridging of the fracture gap by cartilage on the periosteal side was observed only (i) for a rather specific choice of the threshold values for tissue differentiation and (ii) when assuming a strong source of biological stimulation at the periosteum.
The impending Upgrade of the Belle experiment is expected to increase the generated data set by a factor of 50. This means that for the planned pixel detector, which is the closest to the interaction ...point, the data rates are going to increase to up to 28 Gbit s. Combined with data generated by the other detectors, this rate is too big to efficiently send out to offline processing. In order to reduce the data rates online data reduction schemes, in which background is detected and rejected, are going to be employed. In this paper, an approach for efficient online data reduction for the planned pixel detector of Belle-II is presented. Its central part is the NeuroBayes algorithm, which is based on multivariate analysis. It allows the identification of signal and background by analyzing clusters of hits in the pixel detector on FPGAs. The algorithm is leveraging the fact that hits of signal particles can have very different characteristics, compared to background, when passing through the pixel detector. The applicability and advantages in performance are shown through the D* decay. In Belle-II, these decays produce pions with such a small transversal momentum, that they barely escape the pixel detector itself. In a common approach like an extrapolation of tracks from outer detectors to RoIs, these pions are simply lost, since they do not reach all necessary layers of the detector. However, cluster analysis is able to identify and separate these pions from the background, thus keeping their data. For that characteristics of corresponding hits, like the total amount of charge deposited in the pixels, are used for separation. The capability for effective data reduction is underlined by a background reduction of at least 90% and signal efficiency of 95%, for slow pions. An implementation of the algorithm for usage on Virtex-6 FPGAs that are used at the pixel detector was performed. It is shown that the resulting implementation succeeds in replicating the efficiency of the algorithm, implemented in software while throughputs that suffice hard real-time constraints, set by the read-out system of Belle-II, are achieved and efficient use of the resources present on the FPGA is made.
The ongoing COVID-19 pandemic has spotlighted the intricate connections between human and planetary health. Given that pesticide-centered crop protection degrades ecological resilience and ...(in-)directly harms human health, the adoption of ecologically sound, biodiversity-driven alternatives is imperative. In this Synthesis paper, we illuminate how ecological forces can be manipulated to bolster ‘tritrophic defenses’ against crop pests, pathogens, and weeds. Three distinct, yet mutually compatible approaches (habitat-mediated, breeding-dependent, and epigenetic tactics) can be deployed at different organizational levels, that is, from an individual seed to entire farming landscapes. Biodiversity can be harnessed for crop protection through ecological infrastructures, diversification tactics, and reconstituted soil health. Crop diversification is ideally guided by interorganismal interplay and plant–soil feedbacks, entailing resistant cultivars, rotation schemes, or multicrop arrangements. Rewarding opportunities also exist to prime plants for enhanced immunity or indirect defenses. As tritrophic defenses spawn multiple societal cobenefits, they could become core features of healthy, climate-resilient, and low-carbon food systems.
The management of Helicobacter pylori negative patients with dyspepsia in primary care has not been studied in placebo-controlled studies.
H. pylori negative patients with dyspepsia symptoms of at ...least moderate severity (> or =4 on a seven-point Likert scale) were recruited from 35 centers. Patients were randomized to a 4-wk treatment of omeprazole 20 mg od, ranitidine 150 mg bid, cisapride 20 mg bid, or placebo, followed by on-demand therapy for an additional 5 months. Treatment success was defined as no or minimal symptoms (score < or = 2 out of 7), and was assessed after 4 wk and at 6 months.
Five hundred and twelve patients were randomized and included in the intention-to-treat (ITT) analysis. At 4 wk, success rates (95% CI) were: omeprazole 51% (69/135; 43-60%), ranitidine 36% (50/139, 28-44%), cisapride 31% (32/105, 22-39%), and placebo 23% (31/133, 16-31%). Omeprazole was significantly better than all other treatments (p < 0.05). The proportion of patients who were responders at 4 wk and at 6 months was significantly greater for those receiving omeprazole 31% (42/135, 23-39%) compared with cisapride 13% (14/105, 7-20%), and placebo 14% (18/133, 8-20%) (p= 0.001), but not ranitidine 21% (29/139, 14-27%) (p= 0.053). The mean number of on-demand study tablets consumed and rescue antacid used was comparable across groups. Economic analysis showed a trade-off between superior efficacy and increased cost between omeprazole and ranitidine.
Treatment with omeprazole provides superior symptom relief compared to ranitidine, cisapride, and placebo in the treatment of H. pylori negative primary care dyspepsia patients.
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