M13 bacteriophage is a promising biomolecule capable of various bionano and material science applications. The biomaterial can self-assemble into matrices to fabricate bioscaffolds using high phage concentration and high phage purity. Previous studies aimed to acquire these conditions in large-scale phage production and have identified the optimal culture temperature range at 28–31 °C. However, explanations as to why this temperature range was optimal for phage production is absent from the work. Therefore, in this study, we identified the relation between culture temperature and M13 phage production using ATP expenditure calculations to comprehend the high yield phage production at the optimal temperature range. We extended a coarse-grained model for the evaluation of phage protein and ribosomal protein synthesis with the premise that phage proteins (a ribosomal protein) are translated by bacterial ribosomes in E. coli through expenditure of ATP energy. By comparing the ATP energy for ribosomal protein synthesis estimated using the coarse-grained model and the experimentally calculated ATP expenditure for phage production, we interpreted the high phage yield at the optimal temperature range and recognized ATP analysis as a reasonable method that can be used to evaluate other parameters for phage production optimization.

We present an elementary pedagogical derivation of the Brillouin-Wigner and the Rayleigh-Schrödinger perturbation theories with Epstein-Nesbet partitioning. A variant of the Brillouin-Wigner perturbation theory is also introduced, which can be easily extended to the quasi-degenerate case. A main advantage of the new theory is that the computing time required for obtaining the successive higher-order results is minimal after the third-order calculation. We illustrate the accuracy of the new perturbation theory for some simple model systems like the perturbed harmonic oscillator and the particle in a box.

ObjectiveAs the number of patients with COVID-19 increased, at-home care was introduced for the first time in South Korea. This study aimed to analyse the characteristics and outcomes of patients who were treated under at-home care.Design, setting and participantsThis retrospective cohort study targeted patients under at-home care for COVID-19 in Yeongdeungpo-gu in Seoul, Korea, from 18 October 2021 to 12 December 2021. The public health centre selected eligible patients for at-home care and registered with our institution. Nurses monitored patients, and doctors decided to transfer healthcare facilities and release the quarantined patients according to their symptoms.Outcome measuresPatient characteristics during the course of at-home care.ResultsA total of 1422 patients were enrolled and 9574 patient-days were managed. Most patients were aged ≥60 years (22.7% (n=323)), and 82.8% did not have underlying conditions. The median length of care for patients was 8 days (IQR: 5–10 days). During the study period, 986 (69.3%) patients were released from quarantine, 82 (5.8%) patients were transferred to facilities and 354 (24.9%) patients were still under at-home care at the end of the study period. The most common cause of transfer was sustained fever (n=30; 36.6%), followed by dyspnoea and desaturation (n=17; 20.7%). Factors associated with transfer were diabetes (OR: 3.591, 95% CI 1.488 to 8.665, p=0.004), pregnancy (OR: 5.839, 95% CI 1.035 to 32.935, p=0.046) and being presymptomatic at diagnosis (OR: 4.015, 95% CI 1.559 to 10.337, p=0.004).ConclusionsThere were no specific problems related to patient safety when operating at-home care. Patients with risk factors, such as diabetes, were more likely to be transferred to healthcare facilities. For safe at-home care, it is necessary to prepare for an appropriate response to the emergency.

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