36 research outputs found

    Performance of Improved Ground During the 2001 Nisqually Earthquake

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    Several sites in the Seattle area of Washington incorporated ground improvement as liquefaction mitigation or to increase bearing capacity prior to the 2001 Nisqually earthquake. Facilities with improved ground include an earthen dam, a waste repository embankment, lightweight and large plan structures, and bridge columns and approaches. The sites were improved using vibro-replacement stone columns, vibroflotation, or deep dynamic compaction. All sites performed extremely well, despite evidence of liquefaction and minor structural damage nearby. In this paper, 10 sites are summarized, and the performance of three sites located near liquefied or damaged areas will be described in detail. The detailed sites include a large plan commercial property on liquefiable fill improved to a limited lateral extent, a lightweight tilt-up structure located near evidence of liquefaction at King County International Airport, and an earthen dam with its toe retrofitted using vibro-replacement stone columns

    Validity of the acute recovery and stress scale: training monitoring of the German junior national field hockey team

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    The aim of the present study was to examine the sensitivity of the Acute Recovery and Stress Scale (ARSS). This new psychometric questionnaire was developed to assess the physical, mental, emotional, and overall recovery and stress states of athletes. During a five-day field hockey training camp of the German Junior National Field Hockey Team (n = 25) the ARSS was administered every morning and evening. The study indicated swift reactions of the scores of the physical and general factors as well as stability of scores for the emotional factors in accordance with the training schedule. The straining effect of the camp was best reflected by the adaptations of the scales Physical Performance Capability (F (2.9, 60.3) = 10.0, p < 0.001) and Muscular Stress (F (4, 84) = 16.7, p < 0.001). The results support the ability of the ARSS to monitor recovery-stress (im-) balances in this sample. Thus, the questionnaire has shown to be a sensitive and practical tool that might be suitable for elite sport settings

    Selective-area chemical beam epitaxy of in-plane InAs one-dimensional channels grown on InP(001), InP(111)B, and InP(110) surfaces

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    We report on the selective-area chemical beam epitaxial growth of InAs in-plane, one-dimensional (1-D) channels using patterned SiO2_{2}-coated InP(001), InP(111)B, and InP(110) substrates to establish a scalable platform for topological superconductor networks. Top-view scanning electron micrographs show excellent surface selectivity and dependence of major facet planes on the substrate orientations and ridge directions, and the ratios of the surface energies of the major facet planes were estimated. Detailed structural properties and defects in the InAs nanowires (NWs) were characterized by transmission electron microscopic analysis of cross-sections perpendicular to the NW ridge direction and along the NW ridge direction. Electrical transport properties of the InAs NWs were investigated using Hall bars, a field effect mobility device, a quantum dot, and an Aharonov-Bohm loop device, which reflect the strong spin-orbit interaction and phase-coherent transport characteristic in the selectively grown InAs systems. This study demonstrates that selective-area chemical beam epitaxy is a scalable approach to realize semiconductor 1-D channel networks with the excellent surface selectivity and this material system is suitable for quantum transport studies

    A de novo substitution in BCL11B leads to loss of interaction with transcriptional complexes and craniosynostosis

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    Craniosynostosis, the premature ossification of cranial sutures, is a developmental disorder of the skull vault, occurring in approximately 1 in 2250 births. The causes are heterogeneous, with a monogenic basis identified in ~25% of patients. Using whole-genome sequencing, we identified a novel, de novo variant in BCL11B, c.7C>A, encoding an R3S substitution (p.R3S), in a male patient with coronal suture synostosis. BCL11B is a transcription factor that interacts directly with the nucleosome remodelling and deacetylation complex (NuRD) and polycomb-related complex 2 (PRC2) through the invariant proteins RBBP4 and RBBP7. The p.R3S substitution occurs within a conserved amino-terminal motif (RRKQxxP) of BCL11B and reduces interaction with both transcriptional complexes. Equilibrium binding studies and molecular dynamics simulations show that the p.R3S substitution disrupts ionic coordination between BCL11B and the RBBP4-MTA1 complex, a subassembly of the NuRD complex, and increases the conformational flexibility of Arg-4, Lys-5 and Gln-6 of BCL11B. These alterations collectively reduce the affinity of BCL11B p.R3S for the RBBP4-MTA1 complex by nearly an order of magnitude. We generated a mouse model of the BCL11B p.R3S substitution using a CRISPR-Cas9-based approach, and we report herein that these mice exhibit craniosynostosis of the coronal suture, as well as other cranial sutures. This finding provides strong evidence that the BCL11B p.R3S substitution is causally associated with craniosynostosis and confirms an important role for BCL11B in the maintenance of cranial suture patency

    Identification and Clonal Characterisation of a Progenitor Cell Sub-Population in Normal Human Articular Cartilage

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    Background: Articular cartilage displays a poor repair capacity. The aim of cell-based therapies for cartilage defects is to repair damaged joint surfaces with a functional replacement tissue. Currently, chondrocytes removed from a healthy region of the cartilage are used but they are unable to retain their phenotype in expanded culture. The resulting repair tissue is fibrocartilaginous rather than hyaline, potentially compromising long-term repair. Mesenchymal stem cells, particularly bone marrow stromal cells (BMSC), are of interest for cartilage repair due to their inherent replicative potential. However, chondrocyte differentiated BMSCs display an endochondral phenotype, that is, can terminally differentiate and form a calcified matrix, leading to failure in long-term defect repair. Here, we investigate the isolation and characterisation of a human cartilage progenitor population that is resident within permanent adult articular cartilage. Methods and Findings: Human articular cartilage samples were digested and clonal populations isolated using a differential adhesion assay to fibronectin. Clonal cell lines were expanded in growth media to high population doublings and karyotype analysis performed. We present data to show that this cell population demonstrates a restricted differential potential during chondrogenic induction in a 3D pellet culture system. Furthermore, evidence of high telomerase activity and maintenance of telomere length, characteristic of a mesenchymal stem cell population, were observed in this clonal cell population. Lastly, as proof of principle, we carried out a pilot repair study in a goat in vivo model demonstrating the ability of goat cartilage progenitors to form a cartilage-like repair tissue in a chondral defect. Conclusions: In conclusion, we propose that we have identified and characterised a novel cartilage progenitor population resident in human articular cartilage which will greatly benefit future cell-based cartilage repair therapies due to its ability to maintain chondrogenicity upon extensive expansion unlike full-depth chondrocytes that lose this ability at only seven population doublings

    Basement membrane components are key players in specialized extracellular matrices

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    More than three decades ago, basement membranes (BMs) were described as membrane-like structures capable of isolating a cell from and connecting a cell to its environment. Since this time, it has been revealed that BMs are specialized extracellular matrices (sECMs) with unique components that support important functions including differentiation, proliferation, migration, and chemotaxis of cells during development. The composition of these sECM is as unique as the tissues to which they are localized, opening the possibility that such matrices can fulfill distinct functions. Changes in BM composition play significant roles in facilitating the development of various diseases. Furthermore, tissues have to provide sECM for their stem cells during development and for their adult life. Here, we briefly review the latest research on these unique sECM and their components with a special emphasis on embryonic and adult stem cells and their niches

    SARS-CoV-2 susceptibility and COVID-19 disease severity are associated with genetic variants affecting gene expression in a variety of tissues

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    Variability in SARS-CoV-2 susceptibility and COVID-19 disease severity between individuals is partly due to genetic factors. Here, we identify 4 genomic loci with suggestive associations for SARS-CoV-2 susceptibility and 19 for COVID-19 disease severity. Four of these 23 loci likely have an ethnicity-specific component. Genome-wide association study (GWAS) signals in 11 loci colocalize with expression quantitative trait loci (eQTLs) associated with the expression of 20 genes in 62 tissues/cell types (range: 1:43 tissues/gene), including lung, brain, heart, muscle, and skin as well as the digestive system and immune system. We perform genetic fine mapping to compute 99% credible SNP sets, which identify 10 GWAS loci that have eight or fewer SNPs in the credible set, including three loci with one single likely causal SNP. Our study suggests that the diverse symptoms and disease severity of COVID-19 observed between individuals is associated with variants across the genome, affecting gene expression levels in a wide variety of tissue types

    SARS-CoV-2 susceptibility and COVID-19 disease severity are associated with genetic variants affecting gene expression in a variety of tissues

    Get PDF
    Variability in SARS-CoV-2 susceptibility and COVID-19 disease severity between individuals is partly due to genetic factors. Here, we identify 4 genomic loci with suggestive associations for SARS-CoV-2 susceptibility and 19 for COVID-19 disease severity. Four of these 23 loci likely have an ethnicity-specific component. Genome-wide association study (GWAS) signals in 11 loci colocalize with expression quantitative trait loci (eQTLs) associated with the expression of 20 genes in 62 tissues/cell types (range: 1:43 tissues/gene), including lung, brain, heart, muscle, and skin as well as the digestive system and immune system. We perform genetic fine mapping to compute 99% credible SNP sets, which identify 10 GWAS loci that have eight or fewer SNPs in the credible set, including three loci with one single likely causal SNP. Our study suggests that the diverse symptoms and disease severity of COVID-19 observed between individuals is associated with variants across the genome, affecting gene expression levels in a wide variety of tissue types

    A first update on mapping the human genetic architecture of COVID-19

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    Modification and applicability of questionnaires to assess the recovery-stress state among adolescent and child athletes

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    Despite the general consensus regarding the implementation of self-report measures in the training monitoring, there is a lack of research about their applicability and comprehensibility among developing athletes. However, this target group needs special considerations to manage the increasing training demands while maintaining health and performance. This study deals with challenges of applying recovery-stress questionnaires which were validated with adult populations among developing athletes and presents a possible approach to enhance their applicability. In two phases, the Acute Recovery and Stress Scale (ARSS), a 32-adjective list covering eight scales, and the 8-item derived version, the Short Recovery and Stress Scale (SRSS) were answered by 1052 athletes between 10 and 16 years. Phase 1 included 302 14- to 16-year-old athletes who used the original questionnaires with the additional option to mark "I don't understand," while modified versions with additional explanations (phase 2) were applied to 438 adolescents (14.7 +/- 0.6 years) and 312 child athletes (11.8 +/- 1.1 years). Data of the original validation sample (n = 442) were reanalyzed to examine measurement invariance between adults and adolescents. The results showed comparable psychometric properties to the validation sample (e.g., r(it) > 0.30) and acceptable fit indices via confirmatory factor analyses (CFA), although more difficulties and limitations were present within the younger groups (e.g., Cronbach's alpha between 0.50 and 0.87), especially among 10- and 11-year-olds. The original as well as the modified SRSS, on the other hand, indicated good applicability (Cronbach's alpha between 0.72 and 0.80). Multigroup CFA revealed measurement invariance of the original ARSS among adults and adolescents and of the modified ARSS among adolescents and children. Overall, the present study confirmed the assumption that questionnaires designed by and for adults cannot be directly transferred to younger athletes. The peculiarities and differences in the cognitive and affective development of each age group need to be considered. Future research needs to identify a cut-off age to start the proper use of psychometric tools, especially for state-oriented assessments for routine application in training monitoring. Further modifications and long-term investigations are necessary to implement psychometric monitoring in high-performance environments within youth sport
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