The impact of temperature on the transmissibility potential and virulence of COVID-19 in Tokyo, Japan.
ABSTRACT: Assessing the impact of temperature on COVID-19 epidemiology is critical for implementing non-pharmaceutical interventions. However, few studies have accounted for the nature of contagious diseases, i.e., their dependent happenings. We aimed to quantify the impact of temperature on the transmissibility and virulence of COVID-19 in Tokyo, Japan, employing two epidemiological measurements of transmissibility and severity: the effective reproduction number ([Formula: see text]) and case fatality risk (CFR). We estimated the [Formula: see text] and time-delay adjusted CFR and to subsequently assess the nonlinear and delayed effect of temperature on [Formula: see text] and time-delay adjusted CFR. For [Formula: see text] at low temperatures, the cumulative relative risk (RR) at the first temperature percentile (3.3 °C) was 1.3 (95% confidence interval (CI): 1.1-1.7). As for the virulence to humans, moderate cold temperatures were associated with higher CFR, and CFR also increased as the temperature rose. The cumulative RR at the 10th and 99th percentiles of temperature (5.8 °C and 30.8 °C) for CFR were 3.5 (95% CI: 1.3-10.0) and 6.4 (95% CI: 4.1-10.1). Our results suggest the importance to take precautions to avoid infection in both cold and warm seasons to avoid severe cases of COVID-19. The results and our proposed approach will also help in assessing the possible seasonal course of COVID-19 in the future.
Project description:Coronavirus disease (COVID-19) has been spreading all over the world; however, its incidence and case-fatality ratio differ greatly between countries and between continents. We investigated factors associated with international variation in COVID-19 incidence and case-fatality ratio (CFR) across 107 northern hemisphere countries, using publicly available COVID-19 outcome data as of 14 September 2020. We included country-specific geographic, demographic, socio-economic features, global health security index (GHSI), healthcare capacity, and major health behavior indexes in multivariate models to explain this variation. Multiple linear regression highlighted that incidence was associated with ethnic region (p < 0.05), global health security index 4 (GHSI4) (beta coefficient [β] 0.50, 95% Confidence Interval [CI] 0.14-0.87), population density (β 0.35, 95% CI 0.10-0.60), and water safety level (β 0.51, 95% CI 0.19-0.84). The CFR was associated with ethnic region (p < 0.05), GHSI4 (β 0.53, 95% CI 0.14-0.92), proportion of population over 65 (β 0.71, 95% CI 0.19-1.24), international tourism receipt level (β - 0.23, 95% CI - 0.43 to - 0.03), and the number of physicians (β - 0.37, 95% CI - 0.69 to - 0.06). Ethnic region was the most influential factor for both COVID-19 incidence (partial [Formula: see text] = 0.545) and CFR (partial [Formula: see text] = 0.372), even after adjusting for various confounding factors.
Project description:The growth of SrRuO[Formula: see text] (SRO) thin film with high-crystallinity and low residual resistivity (RR) is essential to explore its intrinsic properties. Here, utilizing the adsorption-controlled growth technique, the growth condition of initial SrO layer on TiO[Formula: see text]-terminated SrTiO[Formula: see text] (STO) (001) substrate was found to be crucial for achieving a low RR in the resulting SRO film grown afterward. The optimized initial SrO layer shows a c(2 [Formula: see text] 2) superstructure that was characterized by electron diffraction, and a series of SRO films with different thicknesses (ts) were then grown. The resulting SRO films exhibit excellent crystallinity with orthorhombic-phase down to [Formula: see text] 4.3 nm, which was confirmed by high resolution X-ray measurements. From X-ray azimuthal scan across SRO orthorhombic (02 ± 1) reflections, we uncover four structural domains with a dominant domain of orthorhombic SRO  along cubic STO  direction. The dominant domain population depends on t, STO miscut angle ([Formula: see text]), and miscut direction ([Formula: see text]), giving a volume fraction of about 92 [Formula: see text] for [Formula: see text] 26.6 nm and [Formula: see text] (0.14[Formula: see text], 5[Formula: see text]). On the other hand, metallic and ferromagnetic properties were well preserved down to t [Formula: see text] 1.2 nm. Residual resistivity ratio (RRR = [Formula: see text]/[Formula: see text]) reduces from 77.1 for t [Formula: see text] 28.5 nm to 2.5 for t [Formula: see text] 1.2 nm, while [Formula: see text] increases from 2.5 [Formula: see text]cm for t [Formula: see text] 28.5 nm to 131.0 [Formula: see text]cm for t [Formula: see text] 1.2 nm. The ferromagnetic onset temperature ([Formula: see text]) of around 151 K remains nearly unchanged down to t [Formula: see text] 9.0 nm and decreases to 90 K for t [Formula: see text] 1.2 nm. Our finding thus provides a practical guideline to achieve high crystallinity and low RR in ultra-thin SRO films by simply adjusting the growth of initial SrO layer.
Project description:<h4>Objectives</h4>The main aim of this study was to find the prevalence of mortality among hospitalized COVID-19 infected patients and associated risk factors for death.<h4>Methods</h4>Three electronic databases including PubMed, Science Direct and Google Scholar were searched to identify relevant cohort studies of COVID-19 disease from January 1, 2020, to August 11, 2020. A random-effects model was used to calculate pooled prevalence rate (PR), risk ratio (RR) and 95% confidence interval (CI) for both effect measures. Cochrane chi-square test statistic Q, [Formula: see text], and [Formula: see text] tests were used to measure the presence of heterogeneity. Publication bias and sensitivity of the included studies were also tested.<h4>Results</h4>In this meta-analysis, a total of 58 studies with 122,191 patients were analyzed. The pooled prevalence rate of mortality among the hospitalized COVID-19 patients was 18.88%, 95% CI (16.46-21.30), p?<?0.001. Highest mortality was found in Europe [PR 26.85%, 95% CI (19.41-34.29), p?<?0.001] followed by North America [PR 21.47%, 95% CI (16.27-26.68), p?<?0.001] and Asia [PR 14.83%, 95% CI (12.46- 17.21), p?<?0.001]. An significant association were found between mortality among COVID-19 infected patients and older age (>?65 years vs.?<?65 years) [RR 3.59, 95% CI (1.87-6.90), p?<?0.001], gender (male vs. female) [RR 1.63, 95% CI (1.43-1.87), p?<?0.001], ICU admitted patients [RR 3.72, 95% CI (2.70-5.13), p?<?0.001], obesity [RR 2.18, 95% CI (1.10-4.34), p?<?0.05], hypertension [RR 2.08,95% CI (1.79-2.43) p?<?0.001], diabetes [RR 1.87, 95% CI (1.23-2.84), p?<?0.001], cardiovascular disease [RR 2.51, 95% CI (1.20-5.26), p?<?0.05], and cancer [RR 2.31, 95% CI (1.80-2.97), p?<?0.001]. In addition, significant association for high risk of mortality were also found for cerebrovascular disease, COPD, coronary heart disease, chronic renal disease, chronic liver disease, chronic lung disease and chronic kidney disease.<h4>Conclusion</h4>This meta-analysis revealed that the mortality rate among COVID-19 patients was highest in the European region and older age, gender, ICU patients, patients with comorbidity had a high risk for case fatality. Those findings would help the health care providers to reduce the mortality rate and combat this pandemic to save lives using limited resources.
Project description:This paper presents a study of early epidemiological assessment of COVID-19 transmission dynamics in Indonesia. The aim is to quantify heterogeneity in the numbers of secondary infections. To this end, we estimate the basic reproduction number [Formula: see text] and the overdispersion parameter [Formula: see text] at two regions in Indonesia: Jakarta-Depok and Batam. The method to estimate [Formula: see text] is based on a sequential Bayesian method, while the parameter [Formula: see text] is estimated by fitting the secondary case data with a negative binomial distribution. Based on the first 1288 confirmed cases collected from both regions, we find a high degree of individual-level variation in the transmission. The basic reproduction number [Formula: see text] is estimated at 6.79 and 2.47, while the overdispersion parameter [Formula: see text] of a negative-binomial distribution is estimated at 0.06 and 0.2 for Jakarta-Depok and Batam, respectively. This suggests that superspreading events played a key role in the early stage of the outbreak, i.e., a small number of infected individuals are responsible for large numbers of COVID-19 transmission. This finding can be used to determine effective public measures, such as rapid isolation and identification, which are critical since delay of diagnosis is the most common cause of superspreading events.
Project description:This time-to-event study examines social factors associated with health-seeking and diagnosis of 165 COVID-19 cases in response to the pandemic spread in Shaanxi Province, China. In particular, we investigate the differential access to healthcare in terms of delayed time from symptom onset to first medical visit and subsequently to diagnosis by factors such as sex, age, travel history, and type of healthcare utilization. We show that it takes more time for patients older than 60 (against those under 30) to seek healthcare after developing symptoms (+ 2.5 days, [Formula: see text]), surveillance on people with living or travel history to Wuhan helps shorten the time to the first doctor visit (- 0.8 days) and diagnosis (- 2.2 days, [Formula: see text]). A delay cut is associated with the adoption of intermediary and large hospitals rather than community-based care as primary care choices (- 1.6 days, [Formula: see text] and - 2.2 days, [Formula: see text]). One unit increase of healthcare workers per 1000 people saves patients 0.5 days ([Formula: see text]) for diagnosis from the first doctor visit and 0.6 days ([Formula: see text]) in total. Our analysis of factors associated with the time delay for diagnosis may provide a better understanding of the health-seeking behaviors of patients and the diagnosis capacity of healthcare providers during the COVID-19 pandemic.
Project description:<h4>Background</h4>The early spatiotemporal transmission of COVID-19 remains unclear. The community to healthcare agencies and back to community (CHC) model was tested in our study to simulate the early phase of COVID-19 transmission in Wuhan, China.<h4>Methods</h4>We conducted a retrospective study. COVID-19 case series reported to the Municipal Notifiable Disease Report System of Wuhan from December 2019 to March 2020 from 17 communities were collected. Cases from healthcare workers (HW) and from community members (CM) were distinguished by documented occupations. Overall spatial and temporal relationships between HW and CM COVID-19 cases were visualised. The CHC model was then simulated. The turning point separating phase 1 and phase 2 was determined using a quadratic model. For phases 1 and 2, linear regression was used to quantify the relationship between HW and CM COVID-19 cases.<h4>Results</h4>The spatial and temporal distributions of COVID-19 cases between HWs and CMs were closely correlated. The turning point was 36.85±18.37 (range 15-70). The linear model fitted well for phase 1 (mean R<sup>2</sup>=0.98) and phase 2 (mean R<sup>2</sup>=0.93). In phase 1, the estimated [Formula: see text]s were positive (from 18.03 to 94.99), with smaller [Formula: see text]s (from 2.98 to 15.14); in phase 2, the estimated [Formula: see text]s were negative (from -4.22 to -81.87), with larger [Formula: see text]s (from 5.37 to 78.12).<h4>Conclusion</h4>Transmission of COVID-19 from the community to healthcare agencies and back to the community was confirmed in Wuhan. Prevention and control measures for COVID-19 in hospitals and among HWs are crucial and warrant further attention.
Project description:Relaxor based [Formula: see text] ternary single crystals (PIN-PMN-PT) were reported to have broader temperature usage range [Formula: see text] and comparable piezoelectric properties to [Formula: see text] (PMNT) crystals. In this work, the orientation dependent dielectric, piezoelectric and electromechanical properties for PIN-PMN-PT crystals were investigated along [Formula: see text] and [Formula: see text] directions. The electromechanical couplings [Formula: see text] and [Formula: see text] for [Formula: see text] poled crystals were found to be 0.91 and 0.91, respectively, with piezoelectric coefficients [Formula: see text] and [Formula: see text] on the order of 925 and -1420 pC/N. Of particular significance was the mechanical quality factor [Formula: see text] for [Formula: see text] oriented crystals, which was found to be [Formula: see text], much higher than the [Formula: see text] values of [Formula: see text] oriented relaxor-PT crystals [Formula: see text]. The temperature dependence of the piezoelectric properties exhibited good temperature stability up to their ferroelectric phase transition [Formula: see text], indicating [Formula: see text] and [Formula: see text] oriented PIN-PMN-PT are promising materials for transducer applications, with the latter for high power resonant devices where low loss (high [Formula: see text]) was required.
Project description:Ever since global warming emerged as a serious issue, the development of promising thermoelectric materials has been one of the main hot topics of material science. In this work, we provide an in-depth understanding of the thermoelectric properties of X[Formula: see text]YH[Formula: see text] monolayers (X=Si, Ge; Y=P, As, Sb, Bi) using the density functional theory combined with the Boltzmann transport equation. The results indicate that the monolayers have very low lattice thermal conductivities in the range of 0.09-0.27 Wm[Formula: see text]K[Formula: see text] at room temperature, which are correlated with the atomic masses of primitive cells. Ge[Formula: see text]PH[Formula: see text] and Si[Formula: see text]SbH[Formula: see text] possess the highest mobilities for hole (1894 cm[Formula: see text]V[Formula: see text]s[Formula: see text]) and electron (1629 cm[Formula: see text]V[Formula: see text]s[Formula: see text]), respectively. Si[Formula: see text]BiH[Formula: see text] shows the largest room-temperature figure of merit, [Formula: see text] in the n-type doping ( [Formula: see text] cm[Formula: see text]), which is predicted to reach 3.49 at 800 K. Additionally, Si[Formula: see text]SbH[Formula: see text] and Si[Formula: see text]AsH[Formula: see text] are found to have considerable ZT values above 2 at room temperature. Our findings suggest that the mentioned monolayers are more efficient than the traditional thermoelectric materials such as Bi[Formula: see text]Te[Formula: see text] and stimulate experimental efforts for novel syntheses and applications.
Project description:In order to understand the superconducting gap nature of a [Formula: see text] single crystal with [Formula: see text], in-plane thermal conductivity [Formula: see text], in-plane London penetration depth [Formula: see text], and the upper critical fields [Formula: see text] have been investigated. At zero magnetic field, it is found that no residual linear term [Formula: see text] exists and [Formula: see text] follows a power-law [Formula: see text] (T: temperature) with n = 2.66 at [Formula: see text], supporting nodeless superconductivity. Moreover, the magnetic-field dependence of [Formula: see text]/T clearly shows a shoulder-like feature at a low field region. The temperature dependent [Formula: see text] curves for both in-plane and out-of-plane field directions exhibit clear upward curvatures near [Formula: see text], consistent with the shape predicted by the two-band theory and the anisotropy ratio between the [Formula: see text](T) curves exhibits strong temperature-dependence. All these results coherently suggest that [Formula: see text] is a nodeless, multiband superconductor.
Project description:<h4>Background</h4>New vaccines are being developed to fight the ongoing COVID-19 pandemic. In our study we compared the efficacy of COVID-19 vaccines to prevent COVID-19-related infections and mortality.<h4>Methods</h4>17 randomized clinical trials of COVID-19 vaccines were included after search in databases. We compared COVID-19 vaccines based on symptomatic and severe infections, number of deaths and hospitalizations related to COVID-19. Also, we analyzed the efficacy of COVID-19 against different variants of SARS-CoV-2 as well as according to different age groups. Random effects model using Mantel-Haenzeal method was used to pool relative risk (RR).<h4>Results</h4>Our meta-analysis shows that full vaccination could decrease not only the risk of symptomatic or severe COVID-19, the risk of hospitalization and death caused by COVID-19. COVID-19 vaccines were also effective against variants of SARS-CoV-2 (RR = 0.36; 95% CI [0.25; 0.53], p < 0.0001). However, efficacy of vaccination varied in COVID-19 variant-dependent manner. Moreover, the analysis in different age groups showed that COVID-19 vaccines had the similar results: the risk was slightly lower in adults compared to elderly cohort [Formula: see text] 65 years): (RR = 0.16, 95% CI [0.11; 0.23]) and (RR = 0.19, 95% CI [0.12; 0.30]), respectively.<h4>Conclusions</h4>Data obtained from clinical trials of COVID-19 vaccines looks promising, in order to fully investigate efficacy of the vaccines further clinical examination is required especially considering new SARS-CoV-2 variants.