Xist RNA initiates X inactivation as it spreads in cis across the chromosome. Here, we reveal a biophysical basis for its cis-limited diffusion. Xist RNA and HNRNPK together drive a liquid-liquid phase separation (LLPS) that encapsulates the chromosome.
View Article and Find Full Text PDFWe combine measurements of galaxy velocities from galaxy surveys with measurements of the Weyl potential from the Dark Energy Survey to test the consistency of general relativity at cosmological scales. Taking the ratio of two model-independent observables-the growth rate of structure and the Weyl potential-we obtain new measurements of the E_{G} statistic with precision of 6.0-11.
View Article and Find Full Text PDFThe smooth emergence of shear elasticity is a hallmark of the liquid to glass transition. In a liquid, viscous stresses arise from local structural rearrangements. In the solid, Eshelby has shown that stresses around an inclusion decay as a power law r-D, where D is the dimension of the system.
View Article and Find Full Text PDFThe anterolateral ligament has gained attention as a secondary stabilizer of anterolateral rotatory stability of the knee. This has had implications among sports medicine specialists as an adjunct procedure with anterior cruciate ligament reconstruction to improve stability. As indications have evolved for its use as an anterior cruciate ligament reconstruction augment, so have the techniques for reconstruction.
View Article and Find Full Text PDFIn dense particle systems, the coupling of rotation and translation motion becomes intricate. Here, we report the results of confocal fluorescence microscopy where simultaneous recording of translational and rotational particle trajectories from a bidisperse colloidal dispersion is achieved by spiking the samples with rotational probe particles. The latter consist of colloidal particles containing two fluorescently labeled cores suited for tracking the particle's orientation.
View Article and Find Full Text PDFA cell for synchrotron-based grazing-incidence x-ray diffraction at ambient pressures and moderate temperatures in a controlled gas atmosphere is presented. The cell is suited for the in situ study of thin film samples under catalytically relevant conditions. To some extent, in addition to diffraction, the cell can be simultaneously applied for x-ray reflectometry and fluorescence studies.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2023
While an array of ecological mechanisms has been shown to stabilize natural community dynamics, how the effectiveness of these mechanisms-including both their direction (stabilizing vs. destabilizing) and strength-shifts under a changing climate remains unknown. Using a 35-y dataset (1985 to 2019) from a desert stream in central Arizona (USA), we found that as annual mean air temperature rose 1°C and annual mean precipitation reduced by 40% over the last two decades, macroinvertebrate communities experienced dramatic changes, from relatively stable states during the first 15 y of this study to wildly fluctuating states highly sensitive to climate variability in the last 10 y.
View Article and Find Full Text PDFUnlabelled: Complex adaptive systems - such as critical infrastructures (CI) - are defined by their vast, multi-level interactions and emergent behaviors, but this elaborate web of interactions often conceals relationships. For instance, CI is often reduced to technological components, ignoring that social and ecological components are also embedded, leading to unintentional consequences from disturbance events. Analysis of CI as social-ecological-technological systems (SETS) can support integrated decision-making and increase infrastructure's capacity for resilience to climate change.
View Article and Find Full Text PDFGraefes Arch Clin Exp Ophthalmol
August 2023
Purpose: To investigate the lower visual acuity threshold for recommending intravitreal injection therapy (IVI). The lower limit of 1.3 logMAR best-corrected visual acuity (BCVA) was adopted in 2006 and has been maintained since then.
View Article and Find Full Text PDFBackground And Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is prevalent in most NICUs, with a high rate of skin colonization and subsequent invasive infections among hospitalized neonates. The effectiveness of interventions designed to reduce MRSA infection in the NICU during the coronavirus disease 2019 (COVID-19) pandemic has not been characterized.
Methods: Using the Institute for Healthcare Improvement's Model for Improvement, we implemented several process-based infection prevention strategies to reduce invasive MRSA infections at our level IV NICU over 24 months.
Purpose: To evaluate midterm outcomes, long-term outcomes, and survivorship in the borderline dysplastic population after primary hip arthroscopy.
Methods: A systematic review of current literature was performed with the following key words: "hip, "arthroscopy," "borderline dysplasia," "borderline hip dysplasia," "developmental dysplasia," "ten-year," "survivorship," "10-year," "5-year," "five year," "mid-term," "long-term," "outcomes," "arthroscopic," and "femoroacetabular impingement" in PubMed, Cochrane, and Scopus in March 2022 using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. The following information was recorded: title, author, publication date, study design, demographic, number of hips, follow-up time, study period, indications for hip arthroscopy, patient-reported outcomes (PROs), characteristics of patients converting to total hip arthroplasty (THA), and rates of secondary surgeries and conversion to THA were recorded.
Purpose: (1) To evaluate minimum 10-year PROs (patient-reported outcomes) and survivorship after primary hip arthroscopy and (2) to identify predictors of failure for secondary arthroscopy and conversion to total hip arthroplasty (THA).
Methods: A systematic review of the literature was conducted with the following key words: "hip arthroscopy," "long-term," "outcomes," "ten-year," "survivorship," "10-year," "15-year," "fifteen-year," 20-year," "twenty-year," and "femoroacetabular impingement" in PubMed and Embase in March 2022 using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Level I to Level IV evidence was included and reported on minimum 10-year outcomes or greater after primary hip arthroscopy.
We characterize a system of hard spheres with a simple collision rule that breaks time-reversal symmetry but conserves energy. The collisions lead to an achiral, isotropic, and homogeneous stationary state whose properties are determined in simulations and compared to an approximate theory originally developed for elastic hard spheres. In the nonequilibrium fluid state, velocities are correlated, a phenomenon known from other nonequilibrium stationary states.
View Article and Find Full Text PDFResearch on the evolutionary ecology of urban areas reveals how human-induced evolutionary changes affect biodiversity and essential ecosystem services. In a rapidly urbanizing world imposing many selective pressures, a time-sensitive goal is to identify the emergent issues and research priorities that affect the ecology and evolution of species within cities. Here, we report the results of a horizon scan of research questions in urban evolutionary ecology submitted by 100 interdisciplinary scholars.
View Article and Find Full Text PDFAlthough light is a prominent stimulus for smart materials, the application of photoswitches as light-responsive triggers for phase transitions of porous materials remains poorly explored. Here we incorporate an azobenzene photoswitch in the backbone of a metal-organic framework producing light-induced structural contraction of the porous network in parallel to gas adsorption. Light-stimulation enables non-invasive spatiotemporal control over the mechanical properties of the framework, which ultimately leads to pore contraction and subsequent guest release via negative gas adsorption.
View Article and Find Full Text PDFBackground: An increased posterior tibial slope (PTS) results in greater force on the anterior cruciate ligament (ACL) and is a risk factor for ACL injuries. Biomechanical studies have suggested that a reduction in the PTS angle may lower the risk of ACL injuries. However, the majority of these investigations have been in the adult population.
View Article and Find Full Text PDFIncreased nitrogen (N) deposition threatens global biodiversity, but its effects in arid urban ecosystems are not well studied. In addition to altered N availability, urban environments also experience increases in other pollutants, decreased population connectivity, and altered biotic interactions, which can further impact biodiversity. In deserts, annual plant communities make up most of the plant diversity, support wildlife, and contribute to nutrient cycling and ecosystem processes.
View Article and Find Full Text PDFJ Geophys Res Biogeosci
January 2022
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) both require low oxygen and high organic carbon conditions common in wetland ecosystems. Denitrification permanently removes nitrogen from the ecosystem as a gas while DNRA recycles nitrogen within the ecosystem via production of ammonium. The relative prevalence of denitrification versus DNRA has implications for the fate of nitrate in ecosystems.
View Article and Find Full Text PDFThe human X-chromosome harbors only 4% of our genome but carries over 20% of genes associated with intellectual disability. Given that they inherit only one X-chromosome, males are more frequently affected by X-linked neurodevelopmental genetic disorders than females. However, despite inheriting two X-chromosomes, females can also be affected because X-chromosome inactivation enables only one of two X-chromosomes to be expressed per cell.
View Article and Find Full Text PDFBackground: The open Latarjet has become the most common method of addressing significant glenoid bone loss in patients with recurrent glenohumeral instability.
Purpose: To describe national trends in Latarjet procedures and risk factors for complications associated with this procedure.
Study Design: Cohort study; Level of evidence, 3.
Mean annual temperature and mean annual precipitation drive much of the variation in productivity across Earth's terrestrial ecosystems but do not explain variation in gross primary productivity (GPP) or ecosystem respiration (ER) in flowing waters. We document substantial variation in the magnitude and seasonality of GPP and ER across 222 US rivers. In contrast to their terrestrial counterparts, most river ecosystems respire far more carbon than they fix and have less pronounced and consistent seasonality in their metabolic rates.
View Article and Find Full Text PDFPatella alta is a significant contributor to patellar instability. Historically, distalizing tibial tubercle osteotomy has been recommended for this problem; however, complications such as nonunion, fracture and hardware irritation are concerning. Additionally, the procedure cannot be performed on skeletally immature patients without violation of the proximal tibial physis.
View Article and Find Full Text PDFIntroduction: Total ankle arthroplasty (TAA) has become increasingly utilized over the past 20 years to treat osteoarthritis of the ankle. The efficacy and safety of this procedure has been previously reported, but relatively few studies have documented the risk of postoperative complications associated with TAA over the past 10 years. Thus, the aim of this study is to provide a current report on the safety of TAA, particularly in association with a number of preoperative risk factors.
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