Clathrin uncoating: Auxilin comes to life

AbstractThe DnaJ protein auxilin has been extensively studied in vitro as a cofactor for uncoating clathrin-coated vesicles by the chaperone Hsc70. Recent studies provide the first evidence that auxilin plays this role in vivo, and work on a new mammalian auxilin suggests the protein may have more complex cellular functions

Dimensionless scaling of heat-release-induced planar shock waves in near-critical CO2

We performed highly resolved one-dimensional fully compressible Navier-Stokes simulations of heat-release-induced compression waves in near-critical CO2. The computational setup, inspired by the experimental setup of Miura et al., Phys. Rev. E, 2006, is composed of a closed inviscid (one-dimensional) duct with adiabatic hard ends filled with CO2 at three supercritical pressures. The corresponding initial temperature values are taken along the pseudo-boiling line. Thermodynamic and transport properties of CO2 in near-critical conditions are modeled via the Peng-Robinson equation of state and Chung's Method. A heat source is applied at a distance from one end, with heat release intensities spanning the range 10^3-10^11 W/m^2, generating isentropic compression waves for values < 10^9 W/m^2. For higher heat-release rates such compressions are coalescent with distinct shock-like features (e.g. non-isentropicity and propagation Mach numbers measurably greater than unity) and a non-uniform post-shock state is present due to the strong thermodynamic nonlinearities. The resulting compression wave intensities have been collapsed via the thermal expansion coefficient, highly variable in near-critical fluids, used as one of the scaling parameters for the reference energy. The proposed scaling applies to isentropic thermoacoustic waves as well as shock waves up to shock strength 2. Long-term time integration reveals resonance behavior of the compression waves, raising the mean pressure and temperature at every resonance cycle. When the heat injection is halted, expansion waves are generated, which counteract the compression waves leaving conduction as the only thermal relaxation process. In the long term evolution, the decay in amplitude of the resonating waves observed in the experiments is qualitatively reproduced by using isothermal boundary conditions.Comment: As submitted to AIAA SciTech 2017, available at http://arc.aiaa.org/doi/pdf/10.2514/6.2017-008

The Evidentiary Use of the HLA Blood Test in Virginia

In 1966 Virginia enacted legislation, now section 20-61.2 of the Code of Virginia, providing for the admission into evidence of the results of blood tests in cases involving questions of paternity. In 1982, a second statute, section 20-61.1 of the Code of Virginia, was amended to permit the use of genetic blood grouping tests, including the human leukocyte antigen (HLA) test, as evidence of paternity in child support proceedings. With the enactment of these two statutes, Virginia has joined a growing number of states which recognize the accuracy and reliability of the HLA test in establishing paternity

Alternative derivation of the relativistic contribution to perihelic precession

An alternative derivation of the first-order relativistic contribution to perihelic precession is presented. Orbital motion in the Schwarzschild geometry is considered in the Keplerian limit, and the orbit equation is derived for approximately elliptical motion. The method of solution makes use of coordinate transformations and the correspondence principle, rather than the standard perturbative approach. The form of the resulting orbit equation is similar to that derived from Newtonian mechanics and includes first-order corrections to Kepler's orbits due to general relativity. The associated relativistic contribution to perihelic precession agrees with established first-order results. The reduced radius for the circular orbit is in agreement to first-order with that calculated from the Schwarzschild effective potential. The method of solution is understandable by undergraduate students.Comment: 12 pages, 2 figures. Accepted for publication in the American Journal of Physic

Codeless GPS Applications to Multi-Path: CGAMP

Cordless Global Positioning System (GPS) Applications to Multi-Path (CGAMP) is meeting the challenge of exploiting the L-band signals from the Global Positioning System (GPS) satellites for the measurement of the impulse response of radio transmission channels over space-Earth paths. This approach was originally suggested by E. K. Smith and has been pursued by J. Lemmon, without an affordable implementation being identifiable. In addition to the high cost of a suitable P code correlating GPS receiver, there is also the major impediment of the often announced Department of Defense policy of selective availability/anti-spoof (SA/AS) that clouds reliable access to the wideband (20 MHz) P channel of the GPS signals without cryptographic access. A technique proposed by MacDoran utilizes codeless methods for exploiting the P channel signals implemented by the use of a pair of antennas and cross correlation signal detection

Aggressive Surveillance Is Needed to Detect Endoleaks and Junctional Separation between Device Components after Zenith Fenestrated Aortic Reconstruction

Background Junctional separation and resulting type IIIa endoleak is a well-known problem after EVAR (endovascular aneurysm repair). This complication results in sac pressurization, enlargement, and eventual rupture. In this manuscript, we review the incidence of this late finding in our experience with the Cook Zenith fenestrated endoprosthesis (ZFEN, Bloomington, IN). Methods A retrospective review was performed of a prospectively maintained institutional ZFEN fenestrated EVAR database capturing all ZFENs implanted at a large-volume, academic hospital system. Patients who experienced junctional separation between the fenestrated main body and distal bifurcated graft (with or without type IIIa endoleak) at any time after initial endoprosthesis implantation were subject to further evaluation of imaging and medical records to abstract clinical courses. Results In 110 ZFENs implanted from October 2012 to December 2017 followed for a mean of 1.5 years, we observed a 4.5% and 2.7% incidence of clinically significant junctional separation and type IIIa endoleak, respectively. Junctional separation was directly related to concurrent type Ib endoleak in all 5 patients. Three patients presented with sac enlargement. One patient did not demonstrate any evidence of clinically significant endoleak and had a decreasing sac size during follow-up imaging. The mean time to diagnosis of modular separation in these patients was 40 months. Junctional separation was captured in surveillance in 2 patients and reintervened upon before manifestation of endoleak. However, the remaining 3 patients completed modular separation resulting in rupture and emergent intervention in 2 and an aortic-related mortality in the other. Conclusions Junctional separation between the fenestrated main and distal bifurcated body with the potential for type IIIa endoleak is an established complication associated with the ZFEN platform. Therefore, we advocate for maximizing aortic overlap during the index procedure followed by aggressive surveillance and treatment of stent overlap loss captured on imaging

Performance of a cryogenic system prototype for the XENON1T Detector

We have developed an efficient cryogenic system with heat exchange and associated gas purification system, as a prototype for the XENON1T experiment. The XENON1T detector will use about 3 ton of liquid xenon (LXe) at a temperature of 175K as target and detection medium for a dark matter search. In this paper we report results on the cryogenic system performance focusing on the dynamics of the gas circulation-purification through a heated getter, at flow rates above 50 Standard Liter per Minute (SLPM). A maximum flow of 114 SLPM has been achieved, and using two heat exchangers in parallel, a heat exchange efficiency better than 96% has been measured

Multiple chromosomal rearrangements in a hybrid zone between Littorina saxatilis ecotypes

Both classical and recent studies suggest that chromosomal inversion polymorphisms are important in adaptation and speciation. However, biases in discovery and reporting of inversions make it difficult to assess their prevalence and biological importance. Here, we use an approach based on linkage disequilibrium among markers genotyped for samples collected across a transect between contrasting habitats to detect chromosomal rearrangements de novo. We report 17 polymorphic rearrangements in a single locality for the coastal marine snail, Littorina saxatilis. Patterns of diversity in the field and of recombination in controlled crosses provide strong evidence that at least the majority of these rearrangements are inversions. Most show clinal changes in frequency between habitats, suggestive of divergent selection, but only one appears to be fixed for different arrangements in the two habitats. Consistent with widespread evidence for balancing selection on inversion polymorphisms, we argue that a combination of heterosis and divergent selection can explain the observed patterns and should be considered in other systems spanning environmental gradients. This article is protected by copyright. All rights reserved

Statistical Mechanics of Membrane Protein Conformation: A Homopolymer Model

The conformation and the phase diagram of a membrane protein are investigated via grand canonical ensemble approach using a homopolymer model. We discuss the nature and pathway of $\alpha$-helix integration into the membrane that results depending upon membrane permeability and polymer adsorptivity. For a membrane with the permeability larger than a critical value, the integration becomes the second order transition that occurs at the same temperature as that of the adsorption transition. For a nonadsorbing membrane, the integration is of the first order due to the aggregation of $\alpha$-helices.Comment: RevTeX with 5 postscript figure