Blood transfusion and hepatitis viruses

Transmission of hepatitis viruses has been recognised as an undesirable effect of blood transfusion since the 1940s, when large outbreaks occurred following inoculation with a yellow fever vaccine which contained pooled human plasma. Further reports followed of jaundice occurring several months after transfusions with blood or plasma. It was also noted in studies in the UK that the incidence of icteric hepatitis increased relative to the number of units transfused.After the discovery of the Australia antigen in 1965, its recognition as a marker of hepatitis B virus (HBV) infection and its association with post-transfusion hepatitis (PTH), the subsequent introduction of screening tests for this antigen in the early 1970s led to a marked decrease in the incidence of PTH. However, despite increasingly sensitive testing methods for hepatitis B surface antigen (HBsAg), as it subsequently became designated, viral hepatitis was still considered the commonest lethal complication of blood transfusion. It was clear that there were still a number of cases of PTH that were due neither to hepatitis A virus nor to HBV, and the term 'non-A, non-B hepatitis' (NANBH) was coined.The introduction of molecular techniques enabled clones to be derived from the genome of an agent associated with transfusion-transmitted NANBH, and the proteins derived from these clones were then used to develop nn enzyme linked immunosorbent assay (ELISA) to detect antibodies to this virus, now termed hepatitis C virus (HCV). This ELlSA is now used in most developed countries to screen for HCV antibodies

National strategy for the prevention and management of transfusion-associated hepatitis

The screening of potential blood donors for the hepatitis B (HBV) and C (HCV) viruses has decreased the risk of transfusion-associated hepatitis, There remains. however, a lack of consensus on a number of issues including methods for screening of blood donors and the management of donors found to have markers of hepatitis virus infection. This document outlines the recommendations of a large group of interested individuals including blood transfusion service managers, primary care health authorities, epidemiologists, Virologists, pathologists, gastroenterologists and hepatologists drawn from both the public and the private sector

Which effective viscosity?

Magmas undergoing shear are prime examples of flows that involve the transport of solids and gases by a separate (silicate melt) carrier phase. Such flows are called multiphase, and have attracted much attention due to their important range of engineering applications. Where the volume fraction of the dispersed phase (crystals) is large, the influence of particles on the fluid motion becomes significant and must be taken into account in any explanation of the bulk behaviour of the mixture. For congested magma deforming well in excess of the dilute limit (particle concentrations >40% by volume), sudden changes in the effective or relative viscosity can be expected. The picture is complicated further by the fact that the melt phase is temperature- and shear-rate-dependent. In the absence of a constitutive law for the flow of congested magma under an applied force, it is far from clear which of the many hundreds of empirical formulae devised to predict the rheology of suspensions as the particle fraction increases with time are best suited. Some of the more commonly used expressions in geology and engineering are reviewed with an aim to home in on those variables key to an improved understanding of magma rheology. These include a temperature, compositional and shear-rate dependency of viscosity of the melt phase with the shear-rate dependency of the crystal (particle) packing arrangement. Building on previous formulations, a new expression for the effective (relative) viscosity of magma is proposed that gives users the option to define a packing fraction range as a function of shear stress. Comparison is drawn between processes (segregation, clustering, jamming), common in industrial slurries, and structures seen preserved in igneous rocks. An equivalence is made such that congested magma, viewed in purely mechanical terms as a high-temperature slurry, is an inherently non-equilibrium material where flow at large Péclet numbers may result in shear thinning and spontaneous development of layering

Inflation and the Scale Dependent Spectral Index: Prospects and Strategies

We consider the running of the spectral index as a probe of both inflation itself, and of the overall evolution of the very early universe. Surveying a collection of simple single field inflationary models, we confirm that the magnitude of the running is relatively consistent, unlike the tensor amplitude, which varies by orders of magnitude. Given this target, we confirm that the running is potentially detectable by future large scale structure or 21 cm observations, but that only the most futuristic measurements can distinguish between these models on the basis of their running. For any specified inflationary scenario, the combination of the running index and unknown post-inflationary expansion history induces a theoretical uncertainty in the predicted value of the spectral index. This effect can easily dominate the statistical uncertainty with which Planck and its successors are expected to measure the spectral index. More positively, upcoming cosmological experiments thus provide an intriguing probe of physics between TeV and GUT scales by constraining the reheating history associated with any specified inflationary model, opening a window into the "primordial dark age" that follows the end of inflation.Comment: 32 pages. v2 and v3 Minor reference updates /clarification

In-Situ Nuclear Magnetic Resonance Investigation of Strain, Temperature, and Strain-Rate Variations of Deformation-Induced Vacancy Concentration in Aluminum

Critical strain to serrated flow in solid solution alloys exhibiting dynamic strain aging (DSA) or Portevin–LeChatelier effect is due to the strain-induced vacancy production. Nuclear magnetic resonance (NMR) techniques can be used to monitor in situ the dynamical behavior of point and line defects in materials during deformation, and these techniques are nondestructive and noninvasive. The new CUT-sequence pulse method allowed an accurate evaluation of the strain-enhanced vacancy diffusion and, thus, the excess vacancy concentration during deformation as a function of strain, strain rate, and temperature. Due to skin effect problems in metals at high frequencies, thin foils of Al were used and experimental results correlated with models based on vacancy production through mechanical work (vs thermal jogs), while in situ annealing of excess vacancies is noted at high temperatures. These correlations made it feasible to obtain explicit dependencies of the strain-induced vacancy concentration on test variables such as the strain, strain rate, and temperature. These studies clearly reveal the power and utility of these NMR techniques in the determination of deformation-induced vacancies in situ in a noninvasive fashion.

New hadrons as ultra-high energy cosmic rays

Ultra-high energy cosmic ray (UHECR) protons produced by uniformly distributed astrophysical sources contradict the energy spectrum measured by both the AGASA and HiRes experiments, assuming the small scale clustering of UHECR observed by AGASA is caused by point-like sources. In that case, the small number of sources leads to a sharp exponential cutoff at the energy E<10^{20} eV in the UHECR spectrum. New hadrons with mass 1.5-3 GeV can solve this cutoff problem. For the first time we discuss the production of such hadrons in proton collisions with infrared/optical photons in astrophysical sources. This production mechanism, in contrast to proton-proton collisions, requires the acceleration of protons only to energies E<10^{21} eV. The diffuse gamma-ray and neutrino fluxes in this model obey all existing experimental limits. We predict large UHE neutrino fluxes well above the sensitivity of the next generation of high-energy neutrino experiments. As an example we study hadrons containing a light bottom squark. These models can be tested by accelerator experiments, UHECR observatories and neutrino telescopes.Comment: 17 pages, revtex style; v2: shortened, as to appear in PR

Indigenous traumatic brain injury research: responding to recruitment challenges in the hospital environment

Background: Hospitals are common recruitment sites for injury and disability studies. However, the clinical and rehabilitation environment can create unique challenges for researchers to recruit participant populations. While there is growing injury and disability focused research involving Indigenous people to understand the types of services and supports required by this population to enhance their recovery experiences, there is limited knowledge of researchers' experiences implementing recruitment processes in the tertiary hospital environment. This paper reflects on the specific challenges of recruiting Indigenous patients following a traumatic brain injury from two tertiary hospitals in Northern Australia. Methods: Between July 2016 and April 2018, research staff recruited eligible patients from one hospital in Queensland and one hospital in the Northern Territory. Qualitative records summarising research staff contact with patients, family members and clinical hospital staff were documented. These qualitative records, in addition to field trip notes and researcher reflections were reviewed to summarise the main challenges in gaining access to patients who fit the eligibility criteria. Results: During the recruitment process, there were five main challenges encountered: (1) Patients discharging against medical advice from hospital; (2) Discharge prior to formal emergence from Post Traumatic Amnesia as per the Westmead Post Trauma Amnesia Scale; (3) Patients under adult guardianship orders; (4) Narrow participant eligibility criteria and (5) Coordinating around patient commitments and treatment. Details of how the recruitment processes were modified throughout the recruitment phase of the study to ensure greater access to patients that met the criteria are described. Conclusion: Based on our recruitment experiences, several recommendations are proposed for future TBI studies with Indigenous Australians. In addition to treatment, Indigenous TBI patients have wide range of needs that must be addressed while in hospital. Patient engagement and data collection processes should be flexible to respond to patient needs and the hospital environment. Employment of a centralized recruiter at each hospital site may help to minimise the challenges researchers need to navigate in the hospital environment. To improve recruitment processes in hospitals, it is essential for researchers examining other health or injury outcomes to describe their recruitment experiences.Michelle S. Fitts, Taeha Condon, John Gilroy, Katrina Bird, Erica Bleakley, Lauren Matheson, Jennifer Fleming, Alan R. Clough, Adrian Esterman, Paul Maruff, and India Bohann

The Physics of turbulent and dynamically unstable Herbig-Haro jets

The overall properties of the Herbig-Haro objects such as centerline velocity, transversal profile of velocity, flow of mass and energy are explained adopting two models for the turbulent jet. The complex shapes of the Herbig-Haro objects, such as the arc in HH34 can be explained introducing the combination of different kinematic effects such as velocity behavior along the main direction of the jet and the velocity of the star in the interstellar medium. The behavior of the intensity or brightness of the line of emission is explored in three different cases : transversal 1D cut, longitudinal 1D cut and 2D map. An analytical explanation for the enhancement in intensity or brightness such as usually modeled by the bow shock is given by a careful analysis of the geometrical properties of the torus.Comment: 17 pages, 10 figures. Accepted for publication in Astrophysics & Spac

Gamma-Ray Bursts: The Underlying Model

A pedagogical derivation is presented of the ``fireball'' model of gamma-ray bursts, according to which the observable effects are due to the dissipation of the kinetic energy of a relativistically expanding wind, a ``fireball.'' The main open questions are emphasized, and key afterglow observations, that provide support for this model, are briefly discussed. The relativistic outflow is, most likely, driven by the accretion of a fraction of a solar mass onto a newly born (few) solar mass black hole. The observed radiation is produced once the plasma has expanded to a scale much larger than that of the underlying ``engine,'' and is therefore largely independent of the details of the progenitor, whose gravitational collapse leads to fireball formation. Several progenitor scenarios, and the prospects for discrimination among them using future observations, are discussed. The production in gamma- ray burst fireballs of high energy protons and neutrinos, and the implications of burst neutrino detection by kilometer-scale telescopes under construction, are briefly discussed.Comment: In "Supernovae and Gamma Ray Bursters", ed. K. W. Weiler, Lecture Notes in Physics, Springer-Verlag (in press); 26 pages, 2 figure