153 research outputs found
Ordering of droplets and light scattering in polymer dispersed liquid crystal films
We study the effects of droplet ordering in initial optical transmittance
through polymer dispersed liquid crystal (PDLC) films prepared in the presence
of an electrical field. The experimental data are interpreted by using a
theoretical approach to light scattering in PDLC films that explicitly relates
optical transmittance and the order parameters characterizing both the
orientational structures inside bipolar droplets and orientational distribution
of the droplets. The theory relies on the Rayleigh-Gans approximation and uses
the Percus-Yevick approximation to take into account the effects due to droplet
positional correlations.Comment: revtex4, 18 pages, 8 figure
Comprehensive overview of the structure and regulation of the glucocorticoid receptor
Glucocorticoids are among the most prescribed drugs worldwide for the treatment of numerous immune and inflammatory disorders. They exert their actions by binding to the glucocorticoid receptor (GR), a member of the nuclear receptor superfamily. There are several GR isoforms resulting from alternative RNA splicing and translation initiation of the GR transcript. Additionally, these isoforms are all subject to several transcriptional, post-transcriptional, and post-translational modifications, all of which affect the protein's stability and/or function. In this review, we summarize recent knowledge on the distinct GR isoforms and the processes that generate them. We also review the importance of all known transcriptional, post-transcriptional, and post-translational modifications, including the regulation of GR by microRNAs. Moreover, we discuss the crucial role of the putative GR-bound DNA sequence as an allosteric ligand influencing GR structure and activity. Finally, we describe how the differential composition and distinct regulation at multiple levels of different GR species could account for the wide and diverse effects of glucocorticoids
Physical characteristics and the talent identification and development processes in male youth soccer: A narrative review
Talent identification and development in male youth soccer are complex and multidimensional processes. The English Football Association “4 Corner Model” is often adopted by academies to support coaches and practitioners to implement a multidisciplinary approach to their talent identification and development framework. This holistic approach is characterized by technical/tactical, psychological, social, and physical attributes, which are central to academy recruitment and individual long-term athlete development. The aim of this narrative review is to provide a critical synthesis of the physical characteristics within this model, which facilitate talent identification and development, namely physical performance, growth and maturation, and the relative age effect
AP-2 complex-mediated endocytosis of Drosophila Crumbs regulates polarity via antagonizing Stardust
Maintenance of epithelial polarity depends on the correct localization and levels of polarity determinants. The evolutionarily conserved transmembrane protein Crumbs is crucial for the size and identity of the apical membrane, yet little is known about the molecular mechanisms controlling the amount of Crumbs at the surface. Here, we show that Crumbs levels on the apical membrane depend on a well-balanced state of endocytosis and stabilization. The adaptor protein 2 (AP-2) complex binds to a motif in the cytoplasmic tail of Crumbs that overlaps with the binding site of Stardust, a protein known to stabilize Crumbs on the surface. Preventing endocytosis by mutations in AP-2 causes expansion of the Crumbs-positive plasma membrane and polarity defects, which can be partially rescued by removing one copy of crumbs. Strikingly, knocking-down both AP-2 and Stardust retains Crumbs on the membrane. This study provides evidence for a molecular mechanism, based on stabilization and endocytosis, to adjust surface levels of Crumbs, which are essential for maintaining epithelial polarity
Astrocytes: orchestrating synaptic plasticity?
Synaptic plasticity is the capacity of a preexisting connection between two
neurons to change in strength as a function of neural activity. Because
synaptic plasticity is the major candidate mechanism for learning and memory,
the elucidation of its constituting mechanisms is of crucial importance in many
aspects of normal and pathological brain function. In particular, a prominent
aspect that remains debated is how the plasticity mechanisms, that encompass a
broad spectrum of temporal and spatial scales, come to play together in a
concerted fashion. Here we review and discuss evidence that pinpoints to a
possible non-neuronal, glial candidate for such orchestration: the regulation
of synaptic plasticity by astrocytes.Comment: 63 pages, 4 figure
Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.
BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700
The Event Horizon General Relativistic Magnetohydrodynamic Code Comparison Project
Recent developments in compact object astrophysics, especially the discovery of merging neutron stars by LIGO, the imaging of the black hole in M87 by the Event Horizon Telescope, and high- precision astrometry of the Galactic Center at close to the event horizon scale by the GRAVITY experiment motivate the development of numerical source models that solve the equations of general relativistic magnetohydrodynamics (GRMHD). Here we compare GRMHD solutions for the evolution of a magnetized accretion flow where turbulence is promoted by the magnetorotational instability from a set of nine GRMHD codes: Athena++, BHAC, Cosmos++, ECHO, H-AMR, iharm3D, HARM-Noble, IllinoisGRMHD, and KORAL. Agreement among the codes improves as resolution increases, as measured by a consistently applied, specially developed set of code performance metrics. We conclude that the community of GRMHD codes is mature, capable, and consistent on these test problems
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