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Background Nurses are experiencing tremendous stress during the new coronavirus disease 2019 (COVID‐19) pandemic, especially intensive care nurses. The pandemic of the disease is a tragedy, which may leave a catastrophic psychological imprint on nurses. Understanding nurses' mental distress can help when implementing interventions to mitigate psychological injuries to nurses. Aims and objectives To quantify the severity of nurses' post‐traumatic stress disorder (PTSD) symptoms and stress and explore the influencing factors of their psychological health when caring for patients with COVID‐19. Design A cross‐sectional survey. Methods The PTSD Checklist‐Civilian and the Perceived Stress Scale were administered from 11 to 18 March 2020, to 90 nurses selected from another city to go and help an intensive care unit (ICU) in Wuhan, China. These nurses were selected because of their high levels of clinical performance and resilience status. Results Nurses' average PTSD score was 24.62 ± 6.68, and five (5.6%) of the nurses reported a clinically significant level of PTSD symptoms (>38 points). Nurses' perceived stress averaged 19.33 ± 7, and 20 nurses (22.22%) scored positively >25 points. Nurses' stress and PTSD symptoms were positively correlated (P < .01). Major stress sources included working in an isolated environment, concerns about personal protective equipment shortage and usage, physical and emotional exhaustion, intensive workload, fear of being infected, and insufficient work experiences with COVID‐19. Conclusions This study showed that even relatively highly resilient nurses experienced some degree of mental distress, including PTSD symptoms and perceived stress. Our findings highlight the importance of helping nurses cultivate resilience and reduce stress. Relevance to clinical practice Recommendations for practice include providing adequate training and orientation before assigning nurses to ICU to help, offering disaster‐emergency‐preparedness training to keep nurses prepared, providing caring and authentic nursing leadership, offering ongoing psychological support to frontline nurses.

Starving microalgae for nitrogen sources is commonly used as a biotechnological tool to boost storage of reduced carbon into starch granules or lipid droplets, but the accompanying changes in bioenergetics have been little studied so far. Here, we report that the selective depletion of Rubisco and cytochrome b  6  f complex that occurs when Chlamydomonas reinhardtii is starved for nitrogen in the presence of acetate and under normoxic conditions is accompanied by a marked increase in chlororespiratory enzymes, which converts the photosynthetic thylakoid membrane into an intracellular matrix for oxidative catabolism of reductants. Cytochrome b  6  f subunits and most proteins specifically involved in their biogenesis are selectively degraded, mainly by the FtsH and Clp chloroplast proteases. This regulated degradation pathway does not require light, active photosynthesis, or state transitions but is prevented when respiration is impaired or under phototrophic conditions. We provide genetic and pharmacological evidence that NO production from intracellular nitrite governs this degradation pathway: Addition of a NO scavenger and of two distinct NO producers decrease and increase, respectively, the rate of cytochrome b  6  f degradation; NO-sensitive fluorescence probes, visualized by confocal microscopy, demonstrate that nitrogen-starved cells produce NO only when the cytochrome b  6  f degradation pathway is activated.

Alphaviruses are enveloped RNA viruses that contain several human pathogens. Due to intrinsic heterogeneity of alphavirus particles, a high resolution structure of the virion is currently lacking. Here we provide a 3.5 Å cryo-EM structure of Sindbis virus, using block based reconstruction method that overcomes the heterogeneity problem. Our structural analysis identifies a number of conserved residues that play pivotal roles in the virus life cycle. We identify a hydrophobic pocket in the subdomain D of E2 protein that is stabilized by an unknown pocket factor near the viral membrane. Residues in the pocket are conserved in different alphaviruses. The pocket strengthens the interactions of the E1/E2 heterodimer and may facilitate virus assembly. Our study provides structural insights into alphaviruses that may inform the design of drugs and vaccines.

An SOFC using semiconductor TiO2 thin film as an electrolyte was designed using the energy band theory to prevent short-circuiting problem.

The biogenesis and assembly of photosystem II (PSII) are mainly regulated by the nuclear-encoded factors. To further identify the novel components involved in PSII biogenesis, we isolated and characterized a high chlorophyll fluorescence low psii accumulation19 (lpa19) mutant, which is defective in PSII biogenesis. LPA19 encodes a Psb27 homolog (At1g05385). Interestingly, another Psb27 homolog (At1g03600) in Arabidopsis was revealed to be required for the efficient repair of photodamaged PSII. These results suggest that the Psb27 homologs play distinct functions in PSII biogenesis and repair in Arabidopsis. Chloroplast protein labeling assays showed that the C-terminal processing of D1 in the lpa19 mutant was impaired. Protein overlay assays provided evidence that LPA19 interacts with D1, and coimmunoprecipitation analysis demonstrated that LPA19 interacts with mature D1 (mD1) and precursor D1 (pD1). Moreover, LPA19 protein was shown to specifically interact with the soluble C terminus present in the precursor and mature D1 through yeast two-hybrid analyses. Thus, these studies suggest that LPA19 is involved in facilitating the D1 precursor protein processing in Arabidopsis. Photosystem II (PSII),2 which catalyzes light-driven water oxidation and plastoquinone reduction, is a large pigment-protein complex found in the thylakoid membranes of cyanobacteria and chloroplasts. In higher plants, PSII contains more than 20 subunits including both integral and peripheral proteins (1, 2). The PSII reaction center proteins D1 and D2 bind most of the redox components essential for primary charge separation. Light energy transfer to the PSII reaction center is mediated by the intrinsic chlorophyll a-binding proteins, CP47 and CP43. The oxygen evolving complex, located on the luminal side of PSII, consists of a manganese cluster and several extrinsic proteins (3-6).

Hepatitis B virus (HBV) infection could cause hepatitis, liver cirrhosis, and hepatocellular carcinoma. HBV-mediated pathogenesis is only partially understood, but X protein (HBx) reportedly possesses oncogenic potential. Exosomes are small membrane vesicles with diverse functions released by various cells including hepatocytes, and HBV harnesses cellular exosome biogenesis and export machineries for virion morphogenesis and secretion. Therefore, HBV infection might cause changes in exosome contents with functional implications for both virus and host. In this work, exosome protein content changes induced by HBV and HBx were quantitatively analyzed by SILAC/LC-MS/MS. Exosomes prepared from SILAC-labeled hepatoma cell line Huh-7 transfected with HBx, wildtype, or HBx-null HBV replicon plasmids were analyzed by LC-MS/MS. Systematic analyses of MS data and confirmatory immunoblotting showed that HBx overexpression and HBV, with or without HBx, replication in Huh-7 cells indeed caused marked and specific changes in exosome protein contents. Furthermore, specific changes in protein contents were also detected in exosomes purified from HBV-infected patients' sera compared with control sera negative for HBV markers. These results illustrate a new aspect of interactions between HBV and the host and provide the foundation for future research into roles played by exosomes in HBV infection and pathogenesis.

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