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Background: Nucleic acid test window periods for HIV, HCV, and HBV facilitate estimation of the residual risk of unexpected disease transmission and assist clinicians in determining the timeframe in which a recently acquired infection is at risk of nondetection. Objectives: Firstly, to provide revised estimates of the NAT window periods based on a currently used triplex NAT assay. Secondly, to examine their validity in organ donation and transplantation practice. Method: Estimates were based on the Procleix Ultrio Elite Assay (Grifols Diagnostic Solutions Inc. California, USA). The manufacturer's X50 and X95 limits of detection (LOD) were utilised. Viral doubling times of 0.85, 0.45, and 2.56 days and conversion factors for IU per ml to copies per mL of 0.6, 3.4, and 5 were assumed for HIV, HCV, and HBV respectively. Window periods were derived from the X50 and X95 LODs, based on a range of potential inoculum volumes. Results: Calculated X50 window periods were 5.1 (4.5–5.8), 2.7 (2.4–2.9), and 16.6 (14.2–19.1) days for HIV, HCV, and HBV respectively. Calculated X50 window periods, based on whole body plasma volume, were 11.8 (10.3–13.3), 6.2 (5.6–6.8) and 36.7 (31.3–42.1) days respectively. Conclusion: X50 NAT window periods were significantly shorter for HBV and HCV and sit at the lower range of previously published estimates for HIV. Current modeling assumptions may not account for all unexpected transmission events and may no longer be suitable for application to organ donation and transplantation. [ABSTRACT FROM AUTHOR]

The characteristics of several laser-based optoelectronic devices are studied. Experiments are performed wherein the typical current-voltage properties of a double heterostructure optoelectronic switch (DOES) and a heterostructure field-effect transistor (HFET) are determined at various hoding voltage levels. Results indicate that the DOES and HFET devices are very useful for the design of smart pixels used in optical data processing.

A new technology to advance optoelectronic integration is presented. It involves a class of optoelectronic devices with an inversion channel heterostructure containing one quantum-well active region. The inversion channel's geometry is such that it may be altered for the designing afield effect transistor, a current injection laser, a field effect modulator ora waveguide photodetector. A discussion on epitaxial growth and fabrication fordevice implementation is also provided.

Background and objectives: Based on the Council of Europe directive which dictates regulatory requirements in Australia, blood donors are currently deferred from donating for 4 months after an endoscopic procedure if either polyps were removed or a biopsy sample was taken. We aimed to assess the incidence of blood‐borne viruses (BBVs) (HIV, hepatitis B and C) in blood donors who donated after an endoscopic procedure and evaluate the risk to blood safety through risk modelling. Materials and methods: Donors from 1/1/2013 to 31/12/2017 with an endoscopy deferral on their blood donor file with pre‐ and post‐BBV testing were analysed to determine an incidence of BBVs using standard methods. The standard blood donor cohort was used as a comparator group. Using the incidence of endoscopies and BBV risk, the total residual risk estimate of allowing donors to return postendoscopy without restriction was calculated. Results: The incidence of a BBV postendoscopy in this large cohort of 16,283 where testing has been confirmed postendoscopy was zero (95% CI 0–0·000105). The upper confidence interval of the zero events is 10·5 per 100 000 donations. Total positive donations from 2017 repeat donors were 1·87 per 100 000 (95% CI 0·0000117–0·0000277). Sensitivity analysis demonstrated that the residual risk remained negligible under realistic worst‐case scenarios. Conclusion: A BBV endoscopy deferral is not required for blood safety in Australia. The presented data has enabled us to submit a request for an exemption to our regulator, which has been approved and the policy change subsequently implemented by Lifeblood on 4/4/2020. [ABSTRACT FROM AUTHOR]

Background and Objective: Severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) is a novel coronavirus, first identified in China at the end of 2019 and has now caused a worldwide pandemic. In this review, we provide an overview of the implications of SARS‐CoV‐2 for blood safety and sufficiency. Material and Method: We searched the PubMed database, the preprint sites bioRxiv and medRxiv, the websites of the World Health Organization, European Centre for Disease Prevention and Control, the US Communicable Diseases Center and monitored ProMed updates. Results: An estimated 15%–46% of SARS‐CoV‐2 infections are asymptomatic. The reported mean incubation period is 3 to 7 days with a range of 1–14 days. The blood phase of SARS‐CoV‐2 appears to be brief and low level, with RNAaemia detectable in only a small proportion of patients, typically associated with more severe disease and not demonstrated to be infectious virus. An asymptomatic blood phase has not been demonstrated. Given these characteristics of SARS‐CoV‐2 infection and the absence of reported transfusion transmission (TT), the TT risk is currently theoretical. To mitigate any potential TT risk, but more importantly to prevent respiratory transmission in donor centres, blood centres can implement donor deferral policies based on travel, disease status or potential risk of exposure. Conclusion: The TT risk of SARS‐CoV‐2 appears to be low. The biggest risk to blood services in the current COVID‐19 pandemic is to maintain the sufficiency of the blood supply while minimizing respiratory transmission of SARS‐CoV‐19 to donors and staff while donating blood. [ABSTRACT FROM AUTHOR]