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SUMMARY: Algae such as diatoms and haptophytes have distinct photosynthetic pigments from plants, including a novel set of carotenoids. This includes a primary xanthophyll cycle comprised of diadinoxanthin and its de‐epoxidation product diatoxanthin that enables the switch between light harvesting and non‐photochemical quenching (NPQ)‐mediated dissipation of light energy. The enzyme responsible for the reversal of this cycle was previously unknown. Here, we identified zeaxanthin epoxidase 3 (ZEP3) from Phaeodactylum tricornutum as the candidate diatoxanthin epoxidase. Knocking out the ZEP3 gene caused a loss of rapidly reversible NPQ following saturating light exposure. This correlated with the maintenance of high concentrations of diatoxanthin during recovery in low light. Xanthophyll cycling and NPQ relaxation were restored via complementation of the wild‐type ZEP3 gene. The zep3 knockout strains showed reduced photosynthetic rates at higher light fluxes and reduced specific growth rate in variable light regimes, likely due to the mutant strains becoming locked in a light energy dissipation state. We were able to toggle the level of NPQ capacity in a time and dose dependent manner by placing the ZEP3 gene under the control of a β‐estradiol inducible promoter. Identification of this gene provides a deeper understanding of the diversification of photosynthetic control in algae compared to plants and suggests a potential target to improve the productivity of industrial‐scale cultures. Significance Statement: This work reveals the identify of the enzyme responsible for the deactivation of the xanthophyll cycle and photoprotection in diatoms. [ABSTRACT FROM AUTHOR]

We studied the optical properties of hybrid multilayer microspheres (HMMs). We prepared multilayer particles with alternating radial layers of gold nanoparticles (NPs) and poly(methyl methacrylate) and achieved control over particle size, the thickness of particle layers, and the surface coverage of gold NPs. We showed the ability to tune the spectral characteristics of the HMMs, which was based on frequency dispersion of the dielectric constant of polymer-metal NP structures. Good agreement between experimental and theoretical extinction properties of the HMMs was obtained. In comparison with multilayer structures synthesized solely from polymers, hybrid multilayer microspheres have a larger refractive layer contrast between adjacent layers, which is important for practical applications in optoelectronic devices. Key words: hybrid polymer-inorganic materials, polymer microspheres, gold nanoparticles, optical properties, extinction spectra. On a etudie les proprietes optiques de microspheres multicouches hybrides (MMH). On a prepare les particules a multicouches comportant des couches radiales alternantes de nanoparticules (NP) d'or et de poly(methacrylate de methyle) et on a pu controler la taille des particules des couches et la surface de la couverture des nanoparticules d'or. On a pu controler les caracteristiques spectrales des microspheres multicouches hybrides en ajustant la frequence de dispersion de la constante de dielectrique des structures des nanoparticules polymere-metal. On a obtenu un bon accord entre les proprietes d'extinction experiinentales et theoriques des microspheres multicouches hybrides. Par comparaison avec les structures multicouches synthetisees uniquement a partir de polymeres, les microspheres multicouches hybrides possedent un plus grand contraste de refraction par couche entre les couches, propriete importante pour les applications pratiques dans les appareils optoelectroniques. Mots-cles : materiaux hybrides polymere-inorganique, microspheres de polymere, nanoparticules d'or, proprietes optiques, spectres d'extinction. [Traduit par la Redaction] doi: 10.1139/V09-172, Introduction Polymer microspheres with a multilayer onion-like structure possess optical properties that are useful in photonic crystals, (1-2) optical data storage, (3-4) biometrics, (5,6) and, sensing and single-particle optical limiting. [...]

Objective: The aim of the present study was to describe the epidemiology and clinical features of patients presenting to the ED with suspected and confirmed COVID‐19. Methods: The COVID‐19 ED (COVED) Project is an ongoing prospective cohort study in Australian EDs. This analysis presents data from eight sites across Victoria and Tasmania for July 2020 (during Australia's 'second wave'). All adult patients who met criteria for 'suspected COVID‐19' and underwent testing for SARS‐CoV‐2 in the ED were eligible for inclusion. Study outcomes included a positive SARS‐CoV‐2 test result and mechanical ventilation. Results: In the period 1 July to 31 July 2020, there were 30 378 presentations to the participating EDs and 2917 (9.6%; 95% confidence interval 9.3–9.9) underwent testing for SARS‐CoV‐2. Of these, 50 (2%) patients returned a positive result. Among positive cases, two (4%) received mechanical ventilation during their hospital admission compared to 45 (2%) of the SARS‐CoV‐2 negative patients (odds ratio 1.7, 95% confidence interval 0.4–7.3; P = 0.47). Two (4%) SARS‐CoV‐2 positive patients died in hospital compared to 46 (2%) of the SARS‐CoV‐2 negative patients (odds ratio 1.7, 95% confidence interval 0.4–7.1; P = 0.49). Strong clinical predictors of a positive SARS‐CoV‐2 result included self‐reported fever, non‐smoking status, bilateral infiltrates on chest X‐ray and absence of a leucocytosis on first ED blood tests (P < 0.05). Conclusion: In this prospective multi‐site study from July 2020, a substantial proportion of ED patients required SARS‐CoV‐2 testing, isolation and enhanced infection prevention and control precautions. Presence of SARS‐CoV‐2 on nasopharyngeal swab was not associated with death or mechanical ventilation. [ABSTRACT FROM AUTHOR]

Artificial light harvesters require ordered arrangement of chromophores. We covalently attach three organic chromophore ligands to silicon dioxide nanoparticles. This allows us to study inter-ligand energy transfer when attached to SiO2 nanoparticles, creating a simple system with a large ratio of donors to acceptors. Using steady-state and transient spectroscopy measurements we quantify this energy transfer between ligands. We show a maximum transfer efficiency of 30% and measure the 2D diffusion length of anthracene carboxylic acid on SiO2 to be between 0.6 and 2.2 nm. [ABSTRACT FROM AUTHOR]

Objective: To determine the relationships between: (i) total ED length of stay (EDLOS) and in‐hospital mortality, ward clinical deterioration; and (ii) between time of bed request, ward transfer and in‐hospital mortality, with a particular focus on patients transferred just prior to a 4 h EDLOS. Methods: Retrospective cohort study using data from three acute care hospitals in Melbourne, Australia. Adult patients admitted from the ED to a non‐monitored ward within 8 h. Patients were sub‐grouped by EDLOS; EDLOS 3.5–4 h compared to 0–3.5 h and 4–8 h. In‐hospital mortality, number of medical emergency team (MET)/cardiac arrest team (CAT) events. Results: A total of 24 746 patients were included: 4396 patients with EDLOS <210 min; 4090 patients with EDLOS of 210–240 min; and 16 260 patients with EDLOS >240 min. Mortality overall was 2.2% (n = 545), highest mortality was seen with EDLOS >4 h (2.4%, n = 399) and lowest in patients with EDLOS 3.5–4 h (1.5%, n = 63, OR 0.67 [95% CI: 0.47–0.93, P = 0.02]). Time from bed request to transfer of >240 min was associated with increased odds of death at hospital discharge (adjusted OR 1.39 [95% CI: 1.08–1.78]). There was no difference in rate of MET calls within 24 h between groups (3.5–4 h = 64 [1.5%], <3.5 h = 60 [1.5%], 4–8 h = 235 [1.4%]). Conclusions: Both shorter time in ED and shorter time between bed request and ward transfer were independently associated with improved outcomes. Whole of hospital measures to reduce length of stay in the ED should focus on shorter ward transfer times after bed request. [ABSTRACT FROM AUTHOR]