Publications by authors named "Walther A"

Background/purpose: This study aims to investigate differences in imaging, procedure utilization, and clinical outcomes of severely injured adolescents treated at adult versus pediatric trauma centers.

Methods: The National Trauma Data Bank was queried retrospectively for adolescents, 15-19years old, with a length of stay (LOS) >1day and Injury Severity Score (ISS) >25 treated at adult (ATC) or pediatric (PTC) Level 1 trauma centers from 2007 to 2011. Patient demographics and utilization of imaging and procedures were analyzed.

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Natural composites are hierarchically structured by combination of ordered colloidal and molecular length scales. They inspire future, biomimetic, and lightweight nanocomposites, in which extraordinary mechanical properties are in reach by understanding and mastering hierarchical structure formation as tools to engineer multiscale deformation mechanisms. Here we describe a hierarchically self-assembled, cholesteric nanocomposite with well-defined colloid-based helical structure and supramolecular hydrogen bonds engineered on the molecular level in the polymer matrix.

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Mechanical gradients are important as tough joints, for strain field engineering in printable electronics, for actuators, and for biological studies, yet they are difficult to prepare and quantitatively characterize. We demonstrate the additive fabrication of gradient bioinspired nanocomposites based on stiff, renewable cellulose nanofibrils that are bottom-up toughened via a tailor-made copolymer. Direct filament writing of different nanocomposite hydrogels in patterns, and subsequent healing of the filaments into continuous films while drying leads to a variety of linear, parabolic and striped bulk gradients.

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The merging of defined nanoscale building blocks with advanced additive manufacturing techniques is of eminent importance for the preparation of multiscale and highly functional materials with de novo designed hierarchical architectures. Here, we demonstrate that hydrogels of cellulose nanofibrils (CNF) can be processed into complex shapes, and used as a sacrificial template to prepare freestanding cell constructs. We showcase our approach for the fabrication of hollow fibers using a controlled extrusion through a circular die into a coagulation bath.

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Article Synopsis
  • Public willingness to participate in research is high in the UK, but complex consent rules create challenges.
  • Research participation registers could simplify recruitment and enhance participation while upholding ethical standards.
  • Balancing these benefits against ethical considerations can lead to increased public involvement in health research without compromising informed consent.
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Representational similarity analysis of activation patterns has become an increasingly important tool for studying brain representations. The dissimilarity between two patterns is commonly quantified by the correlation distance or the accuracy of a linear classifier. However, there are many different ways to measure pattern dissimilarity and little is known about their relative reliability.

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Background: Medical rehabilitation in Germany is characterized by the biopsychosocial model of the ICF. Its complexity makes it less suitable for studies in rehabilitation sciences. For an implementation of the ICF, specific assessment instruments that are able to measure activity and participation efficiently in rehabilitation are needed.

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Background: The German statutory pension insurance (Deutsche Rentenversicherung) rejects about a third of applications for medical rehabilitation. It is assumed that the health and occupational situation of people whose applications are rejected will become unsatisfactory. So far, there are no publications investigating the group of people with rejected applications.

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Block copolymers of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) with varying block sizes were synthesized by consecutive reversible addition-fragmentation chain transfer (RAFT) polymerization and then exposed to cellulose substrates with different anionic charge density. The extent and dynamics of quaternized PDMAEMA-b-POEGMA adsorption on regenerated cellulose, cellulose nanofibrils (CNF), and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCNF) was determined by using electromechanical and optical techniques, namely, quartz crystal microbalance (QCM-D) and surface plasmon resonance (SPR), respectively. PDMAEMA-b-POEGMA equilibrium adsorption increased with the anionic charge of cellulose, an indication of electrostatic interactions.

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Background: The aim of this study was to verify the described inverse stage migration after radical prostatectomy by a tertiary care center in 2011 in a national collective.

Materials And Methods: Data from 10,323 patients with prostate cancer (PCa), who had radical prostatectomy between 1998 and 2012, were analyzed regarding prostate-specific antigen (PSA) and age at diagnosis, T stage, and Gleason score. A trend over time was determined by using the Jonckheere-Terpstra test.

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Natural high-performance materials inspire the pursuit of ordered hard/soft nanocomposite structures at high fractions of reinforcements and with balanced molecular interactions. Herein, we develop a facile, waterborne self-assembly pathway to mimic the multiscale cuticle structure of the crustacean armor by combining hard reinforcing cellulose nanocrystals (CNCs) with soft poly(vinyl alcohol) (PVA). We show iridescent CNC nanocomposites with cholesteric liquid-crystal structure, in which different helical pitches and photonic band gaps can be realized by varying the CNC/PVA ratio.

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Microgels with internal and reconfigurable complex nanostructure are emerging as possible adaptive particles, yet they remain challenging to design synthetically. Here, we report the synthesis of highly charged poly(methacrylic acid) (PMAA) microgels incorporating permanent (poly(methyl methacrylate) (PMMA)) and switchable hydrophobic pockets (poly(N,N'-diethylaminoethyl methacrylate) (PDEAEMA)) via emulsion polymerization. We demonstrate detailed tuning of the size, crosslinking density and tailored incorporation of functional comonomers into the polyacid microgels.

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Kidney transplantation is the optimal treatment of ESRD in children. Some studies have reported inferior outcomes in recipients of LDN allografts who are ≤ 5 yr of age. We performed a retrospective review of pediatric recipient outcomes of 110 LDN allografts at our institution and examined predictors of adverse outcomes.

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Self-regulating reconfigurable soft matter systems are of great interest for creating adaptive and active material properties. Such complex functionalities emerge from non-linear and interactive behavior in space and time as demonstrated by a plethora of dynamic, self-organizing biological structures (e.g.

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Switchable self-assemblies respond to external stimuli with a transition between near-equilibrium states. Although being a key to present-day advanced materials, these systems respond rather passively, and do not display autonomous dynamics. For autonomous behavior, approaches must be found to orchestrate the time domain of self-assemblies, which would lead to new generations of dynamic and self-regulating materials.

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Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder with an increasing prevalence. Affected individuals suffer from a repetitive partial or complete occlusion of the pharyngeal airway despite continued respiratory efforts leading to sleep fragmentation, abnormal gas exchange and significant cardiovascular and metabolic morbidity. Surgical patients with OSA, which in the majority of cases has not been diagnosed prior to surgery, have an increased risk of developing a variety of pulmonary, cardiovascular and other complications throughout the perioperative period.

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Background: Microvascular permeability and leukocyte adhesion are pivotal mechanisms in sepsis pathophysiology contributing to the development of shock and mortality. No effective pharmacological therapy is currently available to restore microvascular barrier function in sepsis. Cholinergic mediators have been demonstrated to exert anti-inflammatory effects during inflammation.

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About 12,000 years ago in the Near East, humans began the transition from hunter-gathering to agriculture-based societies. Barley was a founder crop in this process, and the most important steps in its domestication were mutations in two adjacent, dominant, and complementary genes, through which grains were retained on the inflorescence at maturity, enabling effective harvesting. Independent recessive mutations in each of these genes caused cell wall thickening in a highly specific grain "disarticulation zone," converting the brittle floral axis (the rachis) of the wild-type into a tough, non-brittle form that promoted grain retention.

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Biliary atresia (BA), a neonatal obstructive cholangiopathy, remains the most common indication for pediatric liver transplantation in the United States. In the murine model of BA, Rhesus rotavirus (RRV) VP4 surface protein determines biliary duct tropism. In this study, we investigated how VP4 governs induction of murine BA.

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Unlabelled: We demonstrate electrically and ionically conducting nacre-mimetic nanocomposites prepared using self-assembly of synthetic nanoclay in combination with

Pedot: PSS and a poly(ionic liquid) polymer from aqueous dispersions. The resulting nacre-mimetics show high degrees of mesoscale order and combine high stiffness and high strength. In terms of conductivities, the resulting hybrids exceed simple additive behavior and display synergetic conductivities due to high levels of interfaces and anisotropic conductivity pathways.

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Designing the reversible interactions of biopolymers remains a grand challenge for an integral mimicry of mechanically superior biological composites. Yet, they are the key to synergistic combinations of stiffness and toughness by providing sacrificial bonds with hidden length scales. To address this challenge, dynamic polymers were designed with low glass-transition temperature T(g) and bonded by quadruple hydrogen-bonding motifs, and subsequently assembled with high-aspect-ratio synthetic nanoclays to generate nacre-mimetic films.

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Patchy particles are next generation colloidal building blocks for self-assembly and find further use as (bio) sensors. Progress in this direction crucially depends on developing straightforward preparation pathways able to provide patchy particles with highest uniformity and integrating precise, orthogonal, and spatially localized functionalizations to mediate interaction patterns. This continues to be one of the great challenges in colloid science.

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The 19th century witnessed many advances in scientific enzymology and microbiology that laid the foundations for modern biotechnological industries. In the current study, we analyze the content of original lager beer samples from the 1880s, 1890s and 1900s with emphasis on the carbohydrate content and composition. The historic samples include the oldest samples brewed with pure Saccharomyces carlsbergensis yeast strains.

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Sporulation in Ashbya gossypii is induced by nutrient-limited conditions and leads to the formation of haploid spores. Using RNA-seq, we have determined a gene set induced upon sporulation, which bears considerable overlap with that of Saccharomyces cerevisiae but also contains A. gossypii-specific genes.

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A sacrificial templating process using lithographically printed minimal surface structures allows complex de novo geo-metries of delicate hydrogel materials. The hydrogel scaffolds based on cellulose and chitin nanofibrils show differences in terms of attachment of human mesenchymal stem cells, and allow their differentiation into osteogenic outcomes. The approach here serves as a first example toward designer hydrogel scaffolds viable for biomimetic tissue engineering.

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