MApping the Most Massive Overdensities (MAMMOTH) II -- Discovery of an Extremely Massive Overdensity BOSS1441 at z=2.32z=2.32

Cosmological simulations suggest a strong correlation between high optical-depth Ly$\alpha$ absorbers, which arise from the intergalactic medium (IGM), and 3-D mass overdensities on scales of $10-30$ $h^{-1}$ comoving Mpc. By examining the absorption spectra of $\sim$ 80,000 QSO sight-lines over a volume of 0.1 Gpc$^3$ in the Sloan Digital Sky Survey III (SDSS-III), we have identified an extreme overdensity, BOSS1441, which contains a rare group of strong Ly$\alpha$ absorbers at $z=2.32\pm 0.02$. This absorber group is associated with six QSOs at the same redshift on a 30 comoving Mpc scale. Using Mayall/MOSAIC narrowband and broadband imaging, we detect Ly$\alpha$ emitters (LAEs) down to $0.7\times L_{\rm{Ly\alpha}}^*$, and reveal a large-scale structure of Ly$\alpha$ emitters (LAEs) in this field. Our follow-up Large Binocular Telescope (LBT) observations have spectroscopically confirmed 19 galaxies in the density peak. We show that BOSS1441 has an LAE overdensity of $10.8\pm 2.6$ on a 15 comoving Mpc scale which could collapse to a massive cluster with $M\gtrsim10^{15}$ M$_\odot$ at $z\sim0$. This overdensity is among the most massive large-scale structures at $z\sim2$ discovered to date.Comment: 12 pages, 8 figures. submitted to ApJ, Comments are welcom

SBML-SAT: a systems biology markup language (SBML) based sensitivity analysis tool

<p>Abstract</p> <p>Background</p> <p>It has long been recognized that sensitivity analysis plays a key role in modeling and analyzing cellular and biochemical processes. Systems biology markup language (SBML) has become a well-known platform for coding and sharing mathematical models of such processes. However, current SBML compatible software tools are limited in their ability to perform global sensitivity analyses of these models.</p> <p>Results</p> <p>This work introduces a freely downloadable, software package, SBML-SAT, which implements algorithms for simulation, steady state analysis, robustness analysis and local and global sensitivity analysis for SBML models. This software tool extends current capabilities through its execution of global sensitivity analyses using multi-parametric sensitivity analysis, partial rank correlation coefficient, SOBOL's method, and weighted average of local sensitivity analyses in addition to its ability to handle systems with discontinuous events and intuitive graphical user interface.</p> <p>Conclusion</p> <p>SBML-SAT provides the community of systems biologists a new tool for the analysis of their SBML models of biochemical and cellular processes.</p

Enhanced Optoelectronic Response in Bilayer Lateral Heterostructures of Transition Metal Dichalcogenides

Two-dimensional lateral heterojunctions are basic components for low-power and flexible optoelectronics. In contrast to monolayers, devices based on few-layer lateral heterostructures could offer superior performance due to their lower susceptibility to environmental conditions. Here, we report the controlled synthesis of multi-junction bilayer lateral heterostructures based on MoS2-WS2 and MoSe2-WSe2, where the hetero-junctions are created via sequential lateral edge-epitaxy that happens simultaneously in both the first and the second layer. With respect to their monolayer counterparts, bilayer lateral heterostructures yield nearly one order of magnitude higher rectification currents. They also display a clear photovoltaic response, with short circuit currents ~103 times larger than those extracted from the monolayers, in addition to room-temperature electroluminescence. The superior performance of bilayer heterostructures significantly expands the functionalities of 2D crystals

Characteristics and Outcomes of Patients Discharged Directly Home from a Medical Intensive Care Unit

Introduction: Discharging patients directly home from the ICU is becoming increasingly common, largely driven by decreased ward bed availability. We evaluated readmission patterns of ICU patients discharged directly home. Methods: Retrospective review was conducted of direct discharges from the ICU to home between June 2017 and June 2019. The primary outcome of interest was 30-day hospital readmission. Patients were dichotomized by “wait-time” between transfer order and hospital discharge (\u3c24 hours or ≥24 hours). Outcomes were compared using t-test, Fisher exact, and chi-squared. Risk-adjustment was performed using the Mortality Probability Model (MPM0-III). ICU workload was estimated using the nine equivalents of nursing manpower use score (NEMS). Results: 331 patients were identified, with a mean time of 0.72 [0 - 5.84] days between ICU transfer order and discharge to home. 68.3% (226/331) of patients waited \u3c24 hours for discharge. There was no difference in severity-of-illness or admission NEMS between the groups. 10.3% (45/331) of patients presented for evaluation within 30 days of discharge. 10.3% (34/331) of patients were readmitted. There was no significant difference in 30-day readmission between patients who were discharged after waiting \u3c24 hours vs. waiting ≥24 hours (p=0.70). Discussion: Patients returning directly home from the ICU without discharge delay were not readmitted more frequently within 30 days than those discharged after a delay exceeding 24 hours. Further investigation into identifying patients eligible for safe, early discharge may reduce unnecessary critical care resource utilization

Deadenylation is prerequisite for P-body formation and mRNA decay in mammalian cells

Deadenylation is the major step triggering mammalian mRNA decay. One consequence of deadenylation is the formation of nontranslatable messenger RNA (mRNA) protein complexes (messenger ribonucleoproteins [mRNPs]). Nontranslatable mRNPs may accumulate in P-bodies, which contain factors involved in translation repression, decapping, and 5′-to-3′ degradation. We demonstrate that deadenylation is required for mammalian P-body formation and mRNA decay. We identify Pan2, Pan3, and Caf1 deadenylases as new P-body components and show that Pan3 helps recruit Pan2, Ccr4, and Caf1 to P-bodies. Pan3 knockdown causes a reduction of P-bodies and has differential effects on mRNA decay. Knocking down Caf1 or overexpressing a Caf1 catalytically inactive mutant impairs deadenylation and mRNA decay. P-bodies are not detected when deadenylation is blocked and are restored when the blockage is released. When deadenylation is impaired, P-body formation is not restorable, even when mRNAs exit the translating pool. These results support a dynamic interplay among deadenylation, mRNP remodeling, and P-body formation in selective decay of mammalian mRNA

Constraining Very High Mass Population III Stars through He II Emission in Galaxy BDF-521 at z = 7.01

Numerous theoretical models have long proposed that a strong He II 1640 emission line is the most prominent and unique feature of massive Population III (Pop III) stars in high redshift galaxies. The He II 1640 line strength can constrain the mass and IMF of Pop III stars. We use F132N narrowband filter on the Hubble Space Telescope's (HST) Wide Field Camera 3 (WFC3) to look for strong He II lambda 1640 emission in the galaxy BDF-521 at z=7.01, one of the most distant spectroscopically-confirmed galaxies to date. Using deep F132N narrowband imaging, together with our broadband imaging with F125W and F160W filters, we do not detect He II emission from this galaxy, but place a 2-sigma upper limit on the flux of 5.3x10^-19 ergs s^-1 cm^-2. This measurement corresponds to a 2-sigma upper limit on the Pop III star formation rate (SFR_PopIII) of ~ 0.2 M_solar yr^-1, assuming a Salpeter IMF with 50< M/M_solar < 1000. From the high signal-to-noise broadband measurements in F125W and F160W, we fit the UV continuum for BDF-521. The spectral flux density is ~ 3.6x 10^-11 lambda^-2.32 ergs s^-1 cm^-2 A^-1, which corresponds to an overall unobscured SFR of ~ 5 M_solar yr^-1. Our upper limit on SFR_PopIII suggests that massive Pop III stars represent < 4% of the total star formation. Further, the HST high resolution imaging suggests that BDF-521 is an extremely compact galaxy, with a half-light radius of 0.6 kpc.Comment: 14 pages, 2 figures, Accepted for Publication in ApJ

Characteristics and Outcomes of Patients Directly Discharged to Home from the Intensive Care Unit

Introduction: Given the current era of decreasing hospital bed availability, there has been a rise in the practice of direct discharge to home (DDH) from ICUs. We evaluated the demographics, clinical characteristics, outcomes and readmission patterns among DDH patients. Methods: Retrospective review of patients from 2 MICUs from June 2017 to June 2019 at Thomas Jefferson University hospital, an urban tertiary care center. Primary outcome of interest was 30-day hospital readmission. Patients were dichotomized into two groups based on time between ward transfer order and hospital discharge (\u3c24 or ≥24 hours). Risk adjustment performed with Mortality Probability Model (MPM0 -III). ICU workload at admission and discharge was estimated with nine equivalents of nursing manpower use score (NEMS). Patient characteristics compared using t-test and Fisher exact or χ2 test. Results: 331 DDH patients were analyzed, with the majority (68.3%, 226/331) waiting \u3c24 hours for discharge. Mean LOS significantly longer in patients who had waited ≥24 hours prior to discharge compared to that of patients who waited \u3c24 hours (4.63 vs 2.65 days, p\u3c0.001). 10.3% (45/331) presented to TJU for evaluation within 30 days of discharge. Of these patients, 75.6% (34/45) were readmitted. No significant difference in severity-of-illness, admission NEMS, or 30-day readmission between the 2 groups (p=0.70). Discussion: Shorter wait-times for ICU patients after being determined ready for DDH were associated with shorter hospital and ICU LOS but not with an increase in 30-day readmissions. Further examining pre-discharge and post-discharge data could better identify those at risk of readmission

Tissue Plasminogen Activator and Plasminogen Activator Inhibitor 1 Contribute to Sonic Hedgehog-Induced In Vitro Cerebral Angiogenesis

The molecular mechanisms underlying cerebral angiogenesis have not been fully investigated. Using primary mouse brain endothelial cells (MBECs) and a capillary-like tube formation assay, we investigated whether the sonic hedgehog (Shh) signaling pathway is coupled with the plasminogen/plasmin system in mediating cerebral angiogenesis. We found that incubation of MBECs with recombinant human Shh (rhShh) substantially increased the tube formation in naïve MBECs. This was associated with increases in tissue plasminogen activator (tPA) activation and reduction of plasminogen activator inhibitor 1 (PAI-1). Blockage of the Shh pathway with cyclopamine abolished the induction of tube formation and the effect of rhShh on tPA and PAI-1. Addition of PAI-1 reduced rhShh-augmented tube formation. Genetic ablation of tPA in MBECs impaired tube formation and downregulated of vascular endothelial growth factor (VEGF) and angiopoietin 1 (Ang1). Addition of rhShh to tPA−/− MBECs only partially restored the tube formation and upregulated Ang1, but not VEGF, although rhShh increased VEGF and Ang1 expression on wild-type MBECs. Complete restoration of tube formation in tPA−/− MBECs was observed only when both exogenous Shh and tPA were added. The present study provides evidence that tPA and PAI-1 contribute to Shh-induced in vitro cerebral angiogenesis