Publications by authors named "Schnyder S"

Epidemics of infectious diseases posing a serious risk to human health have occurred throughout history. During recent epidemics there has been much debate about policy, including how and when to impose restrictions on behaviour. Policymakers must balance a complex spectrum of objectives, suggesting a need for quantitative tools.

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During epidemics people may reduce their social and economic activity to lower their risk of infection. Such social distancing strategies will depend on information about the course of the epidemic but also on when they expect the epidemic to end, for instance due to vaccination. Typically it is difficult to make optimal decisions, because the available information is incomplete and uncertain.

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Unlabelled: Studies and initiatives such as the "Choosing wisely" (CW) campaign emphasise evidence-based investigations and treatment to avoid overdiagnosis and overtreatment. The perception of the extent of medical overactivity among professionals and drivers behind are not well studied in the paediatric field.

Aim: We aimed to investigate the physicians' opinion and clarify the main drivers regarding medical overactivity in member countries of the European Academy of Paediatrics (EAP).

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Contact inhibition is a cell property that limits the migration and proliferation of cells in crowded environments. Here we investigate the growth dynamics of a cell colony composed of migrating and proliferating cells on a substrate using a minimal model that incorporates the mechanisms of contact inhibition of locomotion and proliferation. We find two distinct regimes.

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Age-related impairment of muscle function severely affects the health of an increasing elderly population. While causality and the underlying mechanisms remain poorly understood, exercise is an efficient intervention to blunt these aging effects. We thus investigated the role of the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a potent regulator of mitochondrial function and exercise adaptation, in skeletal muscle during aging.

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The migration of cells is relevant for processes such as morphogenesis, wound healing, and invasion of cancer cells. In order to move, single cells deform cyclically. However, it is not understood how these shape oscillations influence collective properties.

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The cellular responses induced by mitochondrial dysfunction remain elusive. Intrigued by the lack of almost any glomerular phenotype in patients with profound renal ischemia, we comprehensively investigated the primary sources of energy of glomerular podocytes. Combining functional measurements of oxygen consumption rates, glomerular metabolite analysis, and determination of mitochondrial density of podocytes in vivo, we demonstrate that anaerobic glycolysis and fermentation of glucose to lactate represent the key energy source of podocytes.

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Molecular dynamics simulations of interacting soft disks confined in a heterogeneous quenched matrix of soft obstacles show dynamics which is fundamentally different from that of hard disks. The interactions between the disks can enhance transport when their density is increased, as disks cooperatively help each other over the finite energy barriers in the matrix. The system exhibits a transition from a diffusive to a localized state, but the transition is strongly rounded.

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The age-related impairment in muscle function results in a drastic decline in motor coordination and mobility in elderly individuals. Regular physical activity is the only efficient intervention to prevent and treat this age-associated degeneration. However, the mechanisms that underlie the therapeutic effect of exercise in this context remain unclear.

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Contact inhibition plays a crucial role in cell motility, wound healing, and tumour formation. By mimicking the mechanical motion of cells crawling on a substrate, we constructed a minimal model of migrating cells that naturally gives rise to contact inhibition of locomotion (CIL). The model cell consists of two disks, a front disk (a pseudopod) and a back disk (cell body), which are connected by a finite extensible spring.

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A binary mixture of superparamagnetic colloidal particles is confined between glass plates such that the large particles become fixed and provide a two-dimensional disordered matrix for the still mobile small particles, which form a fluid. By varying fluid and matrix area fractions and tuning the interactions between the superparamagnetic particles via an external magnetic field, different regions of the state diagram are explored. The mobile particles exhibit delocalized dynamics at small matrix area fractions and localized motion at high matrix area fractions, and the localization transition is rounded by the soft interactions [T.

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Skeletal muscle is not only one of the largest, but also one of the most dynamic organs. For example, plasticity elicited by endurance or resistance exercise entails complex transcriptional programs that are still poorly understood. Various signaling pathways are engaged in the contracting muscle fiber and collectively culminate in the modulation of the activity of numerous transcription factors (TFs) and coregulators.

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Low-carbohydrate/high-fat (LCHF) diets are increasingly popular dietary interventions for body weight control and as treatment for different pathological conditions. However, the mechanisms of action are still poorly understood, in particular, in long-term administration. Besides liver, brain, and heart, skeletal muscle is one of the major organs involved in the regulation of physiological and pathophysiological ketosis.

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Skeletal muscle plasticity is a complex process entailing massive transcriptional programs. These changes are mediated by the action of nuclear receptors and other transcription factors. In addition, coregulator proteins have emerged as important players in this process by linking transcription factors to the RNA polymerase II complex and inducing changes in the chromatic structure.

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The kidney has a high energy demand and is dependent on oxidative metabolism for ATP production. Accordingly, the kidney is rich in mitochondria, and mitochondrial dysfunction is a common denominator for several renal diseases. While the mitochondrial master regulator peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is highly expressed in kidney, its role in renal physiology is so far unclear.

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An active lifestyle is crucial to maintain health into old age; inversely, sedentariness has been linked to an elevated risk for many chronic diseases. The discovery of myokines, hormones produced by skeletal muscle tissue, suggests the possibility that these might be molecular mediators of the whole body effects of exercise originating from contracting muscle fibers. Even though less is known about the sedentary state, the lack of contraction-induced myokines or the production of a distinct set of hormones in the inactive muscle could likewise contribute to pathological consequences in this context.

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We introduce fractal liquids by generalizing classical liquids of integer dimensions d=1,2,3 to a noninteger dimension dl. The particles composing the liquid are fractal objects and their configuration space is also fractal, with the same dimension. Realizations of our generic model system include microphase separated binary liquids in porous media, and highly branched liquid droplets confined to a fractal polymer backbone in a gel.

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Resveratrol (RSV) and SRT1720 (SRT) elicit beneficial metabolic effects and are postulated to ameliorate obesity and related metabolic complications. The co-activator, peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α), has emerged as a major downstream effector responsible for metabolic remodeling of muscle and other metabolic tissues in response to RSV or SRT treatment. However, the requirement of PGC-1α in skeletal muscle for the systemic metabolic effects of these compounds has so far not been demonstrated.

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The generic mechanisms of anomalous transport in porous media are investigated by computer simulations of two-dimensional model systems. In order to bridge the gap between the strongly idealized Lorentz model and realistic models of porous media, two models of increasing complexity are considered: a cherry-pit model with hard-core correlations as well as a soft-potential model. An ideal gas of tracer particles inserted into these structures is found to exhibit anomalous transport which extends up to several decades in time.

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The antimicrobial activity of taurolidine was compared with minocycline against microbial species associated with periodontitis (four single strains and a 12-species mixture). Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs), killing as well as activities on established and forming single-species biofilms and a 12-species biofilm were determined. The MICs of taurolidine against single species were always 0.

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The dynamics of two-dimensional fluids confined within a random matrix of obstacles is investigated using both colloidal model experiments and molecular dynamics simulations. By varying fluid and matrix area fractions in the experiment, we find delocalized tracer particle dynamics at small matrix area fractions and localized motion of the tracers at high matrix area fractions. In the delocalized region, the dynamics is subdiffusive at intermediate times, and diffusive at long times, while in the localized regime, trapping in finite pockets of the matrix is observed.

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Introduction: Psychosocial factors have been associated with both a prothrombotic state and an increased risk of venous thromboembolism (VTE). We examined the relation of depressive symptoms and social support with D-dimer, an integrative measure of enhanced coagulation activity, and several additional prothrombotic measures in patients with VTE.

Methods: We studied 173 patients with a previous deep venous thrombosis and/or pulmonary embolism (mean age ± SD 45 ± 14 years, 55% men).

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Objective: The aim of this retrospective study was to assess the long-term results of stripping the insufficient great saphenous vein (GSV) with stump coagulation, closure of the cribriform fascia and some additional measures, which will be described in detail.

Methods: Patients treated from 1998 to 1999 for varicose veins had been invited in 2009 for follow-up colour-coded duplex sonography and had been asked to answer a quality-of-life questionnaire. In 2009, the examinations for the study were conducted at a clinic of angiology by an independent and experienced sonographer.

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We discuss the dynamic behavior of a tagged particle close to a classical localization transition in the framework of the mode-coupling theory of the glass transition. Asymptotic results are derived for the order parameter as well as the dynamic correlation functions and the mean-squared displacement close to the transition. The influence of an infrared cutoff is discussed.

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The location of MLL translocation breakpoints within therapy-related acute myeloid leukemia linked to drugs targeting Topoisomerase II and infant acute leukemia (IAL) are biased toward the intron 11-exon 12 region of MLL, although lacking a comprehensive explanation. To address this, blood samples were taken from breast cancer and lymphoma patients receiving Topoisomerase II inhibitor therapy. Inverse PCR analysis was used to interrogate the exon 12 region of MLL for rearrangements.

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