Unraveling infectious structures, strain variants and species barriers for the yeast prion [PSI+]

Prions are proteins that can access multiple conformations, at least one of which is beta-sheet rich, infectious and self-perpetuating in nature. These infectious proteins show several remarkable biological activities, including the ability to form multiple infectious prion conformations, also known as strains or variants, encoding unique biological phenotypes, and to establish and overcome prion species (transmission) barriers. In this Perspective, we highlight recent studies of the yeast prion [PSI+], using various biochemical and structural methods, that have begun to illuminate the molecular mechanisms by which self-perpetuating prions encipher such biological activities. We also discuss several aspects of prion conformational change and structure that remain either unknown or controversial, and we propose approaches to accelerate the understanding of these enigmatic, infectious conformers

Search for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during the LIGO–Virgo run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate

Clinical evaluation of a wound measurement and documentation system

Abstract: Wound measurement is essential in assessing the progress of wound healing. The most commonly used tools include wound tracings, width and length measurements, and digital photography. These methods have been useful in clinical practice but have some limitations, such as lack of accuracy, difficulty of use, and often entail wound contact. More advanced equipment tends to be bulky, heavy, and expensive. The following reviews the authors’ experience with a new wound measurement and documentation system, the ARANZ Medical Silhouette Mobile™ (ARANZ Medical, Christchurch, New Zealand). This innovative device combines a digital camera and structured lighting in the form of 2 laser beams to automatically correct for image scale and skin curvature, allowing rapid and accurate measurements of the wound surface area and depth. The scanner unit plugs into a standard personal digital assistant to form a portable device that can be easily held and operated using 1 hand. The scanner has been used in clinical practice trials in patients with venous leg ulcers, diabetic foot ulcers, and in the community setting. The scanner was found to be accurate and reliable, easy to learn and use, portable, and compact. The results presented suggest that this device may be a viable choice in the management of different types of chronic wounds

Dynamics and spin relaxation of tempone in a host crystal. An ENDOR, high field EPR and electron spin echo study

We studied in the temperature range 4-300 K the dynamics and the electron spin echo decay of the radical 4-oxo-2,2,6,6,-tetramethyl-1-piperidinyloxyl (tempone) doping substitutionally a single crystal of the diketone 2,2,4,4-tetramethyl-cyclobutan-1,3-dione. Electron nuclear double resonance (ENDOR) and high field electron paramagnetic resonance (EPR) spectra (110 GHz) displayed three types of motion: interconversion between twisted-crossover conformations, rotation of the methyl groups and libration of the radical in the crystal matrix. At room temperature all the motions are fast, and they reach the slow motion regime each at a different temperature, being all slow below 80 K. An approximate value of 9 kJ mol(-1) for the energy barrier hindering the rotation of the tempone methyl groups is estimated. At low temperature their motion is too slow to give any contribution to the echo decay. The echo decays as a linear exponential in the range 100-300 K, due to the radical motions. At T<100 K the interaction with the methyl protons of the matrix is the dominant dephasing mechanism, and the echo decays as a gaussian. At T < 20 K it depends on the square root of the time. Echo decays and electron spin echo envelope modulations (ESEEM) are simulated by using the available theoretical models. A damping of ESEEM superimposed to the echo decay is discussed

MRSA outbreak at a transplantation unit

Methicillin-resistant Staphylococcus aureus (MRSA) infections frequently complicate the post-operative course of transplant recipients, and despite nasal carriage and endemic colonization, MRSA outbreaks are not commonly described. This study reports a case of MRSA outbreak and discusses infection control measures and recommendations for this situation