New porphyrin assemblies containing 17 porphyrin molecules are constructed by using free base TPP-type porphyrins having eight pyrazine moieties 1. Spectroscopic titration of dimeric [meso-tetrakis(2-carboxy-4-nonylphenyl)porphyrinato]zinc(II) 2 with these porphyrins shows that the processes of the formation of the heptadecameric porphyrin assemblies may be analyzed as eight independent equilibrium processes with an identical binding constant. All binding constants are larger than 5 x 107 M-1 which is the determinable upper limit of the present titration method. In all cases, the fluorescence spectrum of the 1:8 mixture of 1 and 2 consists of the major fluorescence of 1 and the minor one of 2.pyrazine complex even in the presence of the large excess of the antenna pigments. The observed spectra are well reconstructed by the form of faF1 + fbF2, where F1 and F2 are the fluorescence of 1 and the 2.pyrazine complex measured separately at the corresponding concentrations. Interestingly, the general trend that values of fa are nearly equal to those of r564 x (1 - fb) in all cases is found, where r564 is the absorption ratios of the 2.pyrazine moiety and the central free base porphyrin in the assemblies at 564 nm. The observation indicates the excitation of the central porphyrin is directly enhanced by the absorption of the antenna pigments even in such large scale assemblies. Thus, the antenna effect for 1 having largest r564 results in 77 times fluorescence enhancement of the central free base porphyrin. The systems also show interesting dependency of energy-transfer efficiencies on the topological arrangement of the antenna elements.

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Predicting the need for hospitalisation of patients with coronavirus disease 2019 (COVID-19) is important for preventing healthcare disruptions. This observational study aimed to use the COVID-19 Registry Japan (COVIREGI-JP) to develop a simple scoring system to predict respiratory failure due to COVID-19 using only underlying diseases and symptoms. A total of 6873 patients with COVID-19 admitted to Japanese medical institutions between 1 June 2020 and 2 December 2020 were included and divided into derivation and validation cohorts according to the date of admission. We used multivariable logistic regression analysis to create a simple risk score model, with respiratory failure as the outcome for young (18–39 years), middle-aged (40–64 years) and older (≥65 years) groups, using sex, age, body mass index, medical history and symptoms. The models selected for each age group were quite different. Areas under the receiver operating characteristic curves for the simple risk score model were 0.87, 0.79 and 0.80 for young, middle-aged and elderly derivation cohorts, and 0.81, 0.80 and 0.67 in the validation cohorts. Calibration of the model was good. The simple scoring system may be useful in the appropriate allocation of medical resources during the COVID-19 pandemic.

<b><i>Introduction:</i></b> Old age is an independent risk factor (RF) for severe COVID-19; evidence for clinico-epidemiological characteristics among elderly COVID-19 patients is scarce. We aimed to analyze clinical and epidemiological characteristics and comorbidities associated with COVID-19 inpatients in age-stratified populations of an elderly COVID-19 cohort. <b><i>Methods:</i></b> We conducted a retrospective cohort study, using nationwide registry data of COVID-19 patients hospitalized before October 31, 2020 (major information entered in the registry as of December 28, 2020). Participants were divided by age according to the Japan Geriatrics Society and the Japan Gerontological Society: pre-old (65–74 years), old (75–89 years), and super-old (≥90 years). Multivariable logistic regression (MLR) analyses were conducted to identify stratified risk and relationships with comorbidities associated with worse outcomes in different age-groups of elderly patients. Demographics and supportive care were evaluated by category. <b><i>Results:</i></b> Data of 4,701 patients from 444 hospitals were included. Most patients (79.3%) had at least one comorbidity; the proportion of patients with hypertension was high in all categories. The proportion of patients with dementia, cardiovascular disease, and cerebrovascular disease increased with age. The percentage of patients who underwent invasive mechanical ventilation/extracorporeal membrane oxygenation was lower in the super-old group. In total, 11.5% of patients died (5.3%, pre-old; 15.2%, old; and 22.4%, super-old). MLR showed that the risk of critical illness differed among age-groups. Male sex was a significant RF in all ages. Collagen disease, moderate to severe renal disorder, and dialysis were significant RFs in older patients, while hematological malignancies and metastatic tumors were more important RFs for severe disease in relatively younger patients. Most of the RFs for critical illnesses were associated with death. <b><i>Conclusion:</i></b> Differences in the epidemiological and clinical characteristics among the different age-groups were found.

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