Utility of point of care ultrasound for identifying dental abscesses in emergency department patients presenting with dental pain

Introduction: Computed tomography (CT) is the current gold standard for diagnosing dental abscesses in the Emergency Department (ED). There are limitations to using CT, including high cost, radiation exposure, and lengthy time to diagnosis. Point of Care Ultrasound (POCUS) is an alternative imaging modality that does not have these limitations, and is already used to diagnose other soft tissue abscesses. The efficacy of POCUS for diagnosing suspected dental abscesses has never been investigated. The purpose of this project is to compare the utility of POCUS to CT in diagnosing suspected dental abscesses in the ED. Methods: A convenience sample of patients presenting to the ED with dental pain were enrolled into a prospective observational cohort study design, when trained providers were available. Patients were eligible for enrollment after a CT was ordered. The ability of POCUS to identify dental abscesses was compared to CT in each patient. Data was collected using REDCap, and analyzed testing for non-inferiority. Results: Preliminary results indicate that POCUS is non-inferior to CT at diagnosing dental abscesses (p=0.002, n=31). Additionally, the time to diagnosis is significantly shorter for POCUS compared to CT (p\u3c0.0001). Conclusions: These results suggest that POCUS may be an adequate tool for evaluating suspected dental abscesses in the ED. Due to decreased time to diagnosis, patients with suspected dental abscesses receiving POCUS instead of CT as an initial diagnostic imaging study may receive treatment and disposition significantly earlier. This could potentially lead to improved outcomes in patients

The Clicker Study

Purpose: A recent study in orthopedics showed that clicker-based learning was more effective than traditional feedback when teaching procedures. We sought to determine whether this principle is applicable to ultrasound skills. Methods: Our prospective randomized control trial used a population of new ultrasound learners. Exclusion criteria included previous ultrasound experience of more than one hour. Students were shown an instructional video on the Focused Assessment with Sonography in Trauma (FAST) exam and randomized to receive clicker or scripted feedback. Each student performed the FAST exam once without feedback, then with either scripted or clicker-based feedback. They were timed and scored on 18 microskills. Results and Conclusions: 45 students were enrolled in the study, with 6 excluded from analysis. This included 24 premedical and 15 medical students. No significant differences were observed between groups for time or accuracy on the FAST exam. Among medical students, there was a trend toward faster results in the clicker group (mean=83 seconds) than the script group (mean=103 seconds) (p=0.22). Among undergraduates, there was a trend toward higher accuracy in the script group (mean=100%) than the clicker group (mean=95%) (p=0.068) and towards faster performance (mean=103 seconds) than the clicker group (mean=121 seconds) (p=0.38). Although no significant differences were observed, there seemed to be a trend toward faster performance with clicker feedback among medical students and faster and more accurate performance with scripted feedback among premedical students. This may be an area for future study

Palmitic Acid Analogs Exhibit Nanomolar Binding Affinity for the HIV-1 CD4 Receptor and Nanomolar Inhibition of gp120-to-CD4 Fusion

Background: We recently reported that palmitic acid (PA) is a novel and efficient CD4 fusion inhibitor to HIV-1 entry and infection. In the present report, based on in silico modeling of the novel CD4 pocket that binds PA, we describe discovery of highly potent PA analogs with increased CD4 receptor binding affinities (Kd) and gp120-to-CD4 inhibition constants (Ki). The PA analogs were selected to satisfy Lipinski’s rule of drug-likeness, increased solubility, and to avoid potential cytotoxicity. Principal Findings: PA analog 2-bromopalmitate (2-BP) was most efficacious with Kd,74 nM and Ki,122 nM, ascorbyl palmitate (6-AP) exhibited slightly higher Kd,140 nM and Ki,354 nM, and sucrose palmitate (SP) was least efficacious binding to CD4 with Kd,364 nM and inhibiting gp120-to-CD4 binding with Ki,1486 nM. Importantly, PA and its analogs specifically bound to the CD4 receptor with the one to one stoichiometry. Significance: Considering observed differences between K i and K d values indicates clear and rational direction for improving inhibition efficacy to HIV-1 entry and infection. Taken together this report introduces a novel class of natural small molecules fusion inhibitors with nanomolar efficacy of CD4 receptor binding and inhibition of HIV-1 entry

Doubling up on supersymmetry in the Higgs sector

We explore the possibility that physics at the TeV scale possesses approximate N =2 supersymmetry, which is reduced to the N =1 minimal supersymmetric extension of the Standard Model (MSSM) at the electroweak scale. This doubling of supersymmetry modifies the Higgs sector of the theory, with consequences for the masses, mixings and couplings of the MSSM Higgs bosons, whose phenomenological consequences we explore in this paper. The mass of the lightest neutral Higgs boson h is independent of tan β at the tree level, and the decoupling limit is realized whatever the values of the heavy Higgs boson masses. Radiative corrections to the top quark and stop squarks dominate over those due to particles in N = 2 gauge multiplets. We assume that these radiative corrections fix mh ≃ 125 GeV, whatever the masses of the other neutral Higgs bosons H, A, a scenario that we term the h2MSSM. Since the H, A bosons decouple from the W and Z bosons in the h2MSSM at tree level, only the LHC constraints on H, A and H± couplings to fermions are applicable. These and the indirect constraints from LHC measurements of h couplings are consistent with mA ≳ 200 GeV for tan β ∈ (2, 8) in the h2MSSM

Gemini planet imager observational calibrations V: Astrometry and distortion

This is the final version of the article. Available from SPIE via the DOI in this record.From Conference Volume 9147: Ground-based and Airborne Instrumentation for Astronomy V, Suzanne K. Ramsay; Ian S. McLean; Hideki Takami, Montréal, Quebec, Canada, June 22, 2014We present the results of both laboratory and on sky astrometric characterization of the Gemini Planet Imager (GPI). This characterization includes measurement of the pixel scale∗ of the integral field spectrograph (IFS), the position of the detector with respect to north, and optical distortion. Two of these three quantities (pixel scale and distortion) were measured in the laboratory using two transparent grids of spots, one with a square pattern and the other with a random pattern. The pixel scale in the laboratory was also estimate using small movements of the artificial star unit (ASU) in the GPI adaptive optics system. On sky, the pixel scale and the north angle are determined using a number of known binary or multiple systems and Solar System objects, a subsample of which had concurrent measurements at Keck Observatory. Our current estimate of the GPI pixel scale is 14.14 ± 0.01 millarcseconds/pixel, and the north angle is -1.00 ± 0.03°. Distortion is shown to be small, with an average positional residual of 0.26 pixels over the field of view, and is corrected using a 5th order polynomial. We also present results from Monte Carlo simulations of the GPI Exoplanet Survey (GPIES) assuming GPI achieves ∼1 milliarcsecond relative astrometric precision. We find that with this precision, we will be able to constrain the eccentricities of all detected planets, and possibly determine the underlying eccentricity distribution of widely separated Jovians.The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). This publication makes use of data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. P.K. and J.R.G. thank support from NASA NNX11AD21G, NSF AST-0909188, and the University of California LFRP-118057. Q.M.K is a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto. The Dunlap Institute is funded through an endowment established by the David Dunlap family and the University of Toronto

A precision study of the fine tuning in the DiracNMSSM

Recently the DiracNMSSM has been proposed as a possible solution to reduce the fine tuning in supersymmetry. We determine the degree of fine tuning needed in the DiracNMSSM with and without non-universal gaugino masses and compare it with the fine tuning in the GNMSSM. To apply reasonable cuts on the allowed parameter regions we perform a precise calculation of the Higgs mass. In addition, we include the limits from direct SUSY searches and dark matter abundance. We find that both models are comparable in terms of fine tuning, with the minimal fine tuning in the GNMSSM slightly smaller.Comment: 20 pages + appendices, 10 figure

Accessible High-Throughput Virtual Screening Molecular Docking Software for Students and Educators

We survey low cost high-throughput virtual screening (HTVS) computer programs for instructors who wish to demonstrate molecular docking in their courses. Since HTVS programs are a useful adjunct to the time consuming and expensive wet bench experiments necessary to discover new drug therapies, the topic of molecular docking is core to the instruction of biochemistry and molecular biology. The availability of HTVS programs coupled with decreasing costs and advances in computer hardware have made computational approaches to drug discovery possible at institutional and non-profit budgets. This paper focuses on HTVS programs with graphical user interfaces (GUIs) that use either DOCK or AutoDock for the prediction of DockoMatic, PyRx, DockingServer, and MOLA since their utility has been proven by the research community, they are free or affordable, and the programs operate on a range of computer platforms

Cholera Toxin B Subunits Assemble into Pentamers - Proposition of a Fly-Casting Mechanism

The cholera toxin B pentamer (CtxB5), which belongs to the AB5 toxin family, is used as a model study for protein assembly. The effect of the pH on the reassembly of the toxin was investigated using immunochemical, electrophoretic and spectroscopic methods. Three pH-dependent steps were identified during the toxin reassembly: (i) acquisition of a fully assembly-competent fold by the CtxB monomer, (ii) association of CtxB monomer into oligomers, (iii) acquisition of the native fold by the CtxB pentamer. The results show that CtxB5 and the related heat labile enterotoxin LTB5 have distinct mechanisms of assembly despite sharing high sequence identity (84%) and almost identical atomic structures. The difference can be pinpointed to four histidines which are spread along the protein sequence and may act together. Thus, most of the toxin B amino acids appear negligible for the assembly, raising the possibility that assembly is driven by a small network of amino acids instead of involving all of them

Oligonucleotide Sequence Motifs as Nucleosome Positioning Signals

To gain a better understanding of the sequence patterns that characterize positioned nucleosomes, we first performed an analysis of the periodicities of the 256 tetranucleotides in a yeast genome-wide library of nucleosomal DNA sequences that was prepared by in vitro reconstitution. The approach entailed the identification and analysis of 24 unique tetranucleotides that were defined by 8 consensus sequences. These consensus sequences were shown to be responsible for most if not all of the tetranucleotide and dinucleotide periodicities displayed by the entire library, demonstrating that the periodicities of dinucleotides that characterize the yeast genome are, in actuality, due primarily to the 8 consensus sequences. A novel combination of experimental and bioinformatic approaches was then used to show that these tetranucleotides are important for preferred formation of nucleosomes at specific sites along DNA in vitro. These results were then compared to tetranucleotide patterns in genome-wide in vivo libraries from yeast and C. elegans in order to assess the contributions of DNA sequence in the control of nucleosome residency in the cell. These comparisons revealed striking similarities in the tetranucleotide occurrence profiles that are likely to be involved in nucleosome positioning in both in vitro and in vivo libraries, suggesting that DNA sequence is an important factor in the control of nucleosome placement in vivo. However, the strengths of the tetranucleotide periodicities were 3–4 fold higher in the in vitro as compared to the in vivo libraries, which implies that DNA sequence plays less of a role in dictating nucleosome positions in vivo. The results of this study have important implications for models of sequence-dependent positioning since they suggest that a defined subset of tetranucleotides is involved in preferred nucleosome occupancy and that these tetranucleotides are the major source of the dinucleotide periodicities that are characteristic of positioned nucleosomes