Respiratory and facial protection: a critical review of recent literature

Infectious micro-organisms may be transmitted by a variety of routes. This is dependent on the particular pathogen and includes bloodborne, droplet, airborne, and contact transmission. Some micro-organisms are spread by more than one route. Respiratory and facial protection is required for those organisms which are usually transmitted via the droplet and/or airborne routes or when airborne particles have been created during 'aerosol-generating procedures'. This article presents a critical review of the recently published literature in this area that was undertaken by Health Protection Scotland and the Healthcare Infection Society and which informed the development of guidance on the use of respiratory and facial protection equipment by healthcare workers.

Guidance on the use of respiratory and facial protection equipment

Infectious micro-organisms may be transmitted by a variety of routes, and some may be spread by more than one route. Respiratory and facial protection is required for those organisms that are usually transmitted via the droplet/airborne route, or when airborne particles have been artificially created, such as during ‘aerosol-generating procedures’. A range of personal protective equipment that provides different degrees of facial and respiratory protection is available. It is apparent from the recent experiences with severe acute respiratory syndrome and pandemic (H1N1) 2009 influenza that healthcare workers may have difficulty in choosing the correct type of facial and respiratory protection in any given clinical situation. To address this issue, the Scientific Development Committee of the Healthcare Infection Society established a short-life working group to develop guidance. The guidance is based upon a review of the literature, which is published separately, and expert consensus.

Electromagnetic transition from the 4+ to 2+ resonance in 8Be measured via the radiative capture in 4He + 4He

An earlier measurement on the 4+ to 2+ radiative transition in 8Be provided the first electromagnetic signature of its dumbbell-like shape. However, the large uncertainty in the measured cross section does not allow a stringent test of nuclear structure models. This Letter reports a more elaborate and precise measurement for this transition, via the radiative capture in the 4He + 4He reaction, improving the accuracy by about a factor of 3. Ab initio calculations of the radiative transition strength with improved three-nucleon forces are also presented. The experimental results are compared with the predictions of the alpha cluster model and ab initio calculations.

Well developed deformation in 42Si

Excited states in (38,40,42) Si nuclei have been studied via in-beam γ-ray spectroscopy with multinucleon removal reactions. Intense radioactive beams of ^{40}S and (44)S provided at the new facility of the RIKEN Radioactive Isotope Beam Factory enabled γ-γ coincidence measurements. A prominent γ line observed with an energy of 742(8) keV in (42) Si confirms the 2(+) state reported in an earlier study. Among the γ lines observed in coincidence with the 2^{+} → 0+ transition, the most probable candidate for the transition from the yrast 4(+) state was identified, leading to a 4(1)+) energy of 2173(14) keV. The energy ratio of 2.93(5) between the 2(1)+ and 4(1)(+) states indicates well-developed deformation in (42) Si at N = 28 and Z = 14. Also for 38,40)Si energy ratios with values of 2.09(5) and 2.56(5) were obtained. Together with the ratio for (42)Si, the results show a rapid deformation development of Si isotopes from N = 24 to N = 28.