Time-varying overdispersion of SARS-CoV-2 transmission during the periods when different variants of concern were circulating in Japan.

Japan has implemented a cluster-based approach for coronavirus disease 2019 (COVID-19) from the pandemic's beginning based on the transmission heterogeneity (overdispersion) of severe acute respiratory coronavirus 2 (SARS-CoV-2). However, studies analyzing overdispersion of transmission among new variants of concerns (VOCs), especially for Omicron, were limited. Thus, we aimed to clarify how the transmission heterogeneity has changed with the emergence of VOCs (Alpha, Delta, and Omicron) using detailed contact tracing data in Yamagata Prefecture, Japan. We estimated the time-varying dispersion parameter ([Formula: see text]) by fitting a negative binomial distribution for each transmission generation. Our results showed that even after the emergence of VOCs, there was transmission heterogeneity of SARS-CoV-2, with changes in [Formula: see text] during each wave. Continuous monitoring of transmission dynamics is vital for implementing appropriate measures. However, a feasible and sustainable epidemiological analysis system should be established to make this possible.

Epidemiology of Coronavirus Disease 2019 in Yamagata Prefecture, Japan, January-May 2020: the Importance of Retrospective Contact Tracing.

Public health interventions have played an important role in controlling coronavirus disease 2019 (COVID-19), which is a rapidly spreading infectious disease. To contribute to future COVID-19 countermeasures, we aimed to verify the results of the countermeasures employed by public health centers (PHCs) against the first wave of COVID-19 in Yamagata Prefecture, Japan (Yamagata). Between January and May 2020, 1,253 patients suspected of SARS-CoV-2 infection were invited for testing. Simultaneously, based on retrospective contact tracings, PHCs investigated the infection sources and transmission routes of laboratory-confirmed COVID-19 cases and tested 928 contacts. Consequently, 69 cases were confirmed between March 31 and May 4, 58 of whom were from among the contacts (84.1%; 95% confidence interval [CI] 75.5-92.7). The spread of infection was triggered in cases harboring epidemiological links outside Yamagata. Subsequently, the number of cases rapidly increased. However, PHCs identified epidemiological links in 61 (88.4%; 95% CI 80.8-96.0) of the 69 cases, and transmission chains up to the fifth generation. Finally, the spread of infection ended after approximately one month. Our results indicate that the identification of infection sources and active case finding from contacts based on retrospective contact tracing was likely to be an effective strategy in ending the first wave of COVID-19 in Yamagata.

Full-thickness reconstruction of the eyelid with rotation flap based on orbicularis oculi muscle and palatal mucosal graft: long-term results in 12 cases.

BACKGROUND: Numerous techniques have been proposed for full-thickness eyelid reconstruction. Previously, we reported full-thickness eyelid reconstruction with a rotation flap based on the orbicularis oculi muscle and palatal mucosal graft. Here, we report long-term results in 12 cases. METHODS: After confirmation of defect size, the mucosal defect was covered with a split-thickness palatal mucosal graft. The rotation flap was elevated at the lateral orbital region and the skin defect was covered. Seven cases were reconstructions after tumour excision and five cases were for lagophthalmos after trauma. In cases of tumour excision, five cases had full defects of the lower eyelid and two cases had defect of the lower eyelid lateral to the punctum. In the cases of lagophthalmos, four cases had upper eyelid contracture and one had lower eyelid contracture. RESULTS: Postoperatively, one case showed severe venous congestion of the flap, which led to scleral show. In the other 11 cases, there were no complications, and cosmetic results were excellent. CONCLUSIONS: With our method, cosmetically good results can be obtained in either upper or lower eyelids. In the rotation flap based on the orbicularis oculi muscle, the undermined area is small, invasion is minimal, and the effects of scar contracture can be minimised. Minimal shrinkage of palatal mucosal grafts prevents the reconstructed eyelid from sagging. In only one case, poor design of the flap led to flap congestion. However, this complication can be avoided with the proper design.

[Comparative study of bactec MGIT 960 AST and conventional proportion method using Ogawa medium for the drug susceptibility testing of Mycobacterium tuberculosis to isoniazid].

OBJECTIVE: To evaluate the accuracy of drug susceptibility testing to isoniazid with BACTEC MGIT 960 (MGIT AST) comparing with the standard proportion method using Ogawa medium. METHOD: A total of 1109 M. tuberculosis strains, which were selected from the collection of RYOKEN drug resistance survey in 2002, were selected and subjected to the susceptibility testing to isoniazid using MGIT AST and 1% Ogawa standard methods. The results from MGIT AST were compared with the judicial diagnosis by Ogawa. The sensitivity to detect drug resistance, the specificity for susceptible strain, the efficiency of overall agreement, and kappa coefficient were calculated to evaluate the performance. The treatment process, outcome and prognosis were analysed for the patients on whom the tests showed discrepant results. RESULTS: Compared with the judicial results, the sensitivity, specificity, efficiency, and kappa coefficient of MGIT AST were 100%, 97.1%, 97.3%, and 0.798, respectively. The strains, which showed discrepant results between MGIT AST and Ogawa, were all susceptible by Ogawa and resistant by MGIT AST. A total of 11 out of 30 discrepant cases were followed clinically and no relapse cases were identified, irrespective of the modification of the treatment regimen. As for the proportion of primary INH drug resistance in the present study, it was 5.3% with MGIT AST but was 2.7% with Ogawa, and the difference was statistically significant (p = 0.005). DISCUSSION: The discrepancies on the results of drug susceptibility testing of M. tuberculosis strains to isoniazid between MGIT AST and 1% Ogawa proportion method have been reported. In the present study, the sensitivity, specificity, and overall efficiency of MGIT AST on the prevalent strains in Japan were all beyond 95%, and considered sufficient as the anti-tuberculosis drug susceptibility testing (AST), though 2.7% of discrepancy was observed. Even for the discrepant cases, there was no difference in the treatment outcome and prognosis. Thus, MGIT AST was confirmed as a reliable AST method comparable to Ogawa standard. However, MGIT AST might increase the proportion of INH resistance if it was used as a major AST method, compared with Ogawa.

NCEER - Taisei Corporation Research Program on sliding seismic isolation systems for bridges : Experimental and analytical study of systems consisting of sliding bearings, rubber restoring force devices and fluid dampers

This report describes the results of an experimental study of the behavior of a class of sliding isolation systems, consisting of flat sliding bearings, rubber restoring force debices and fluid dampers, in bridge seismic isolation. Earthquake simulator tests have been perfomed on a model bridge structure both isolated with these systems and non-isolated. The experimental results demonstrate a market increase of the capacity of the isolated bridge to withstand earthquake forces under all conditions. Analytical techniques are used to predict the dynamic response of the system and the obtained results are in very good agreement with the experimental results.(AU)

Experimental and analytical study of a hybrid isolation system using friction controllable sliding bearings

This study deals with a hybrid isolation system using friction controllable sliding bearings [1,2]. During earthquakes, this isolation system controls the friction force on the sliding interface between the supported structure and the ground, by adjusting the pressure in a bearing chamber,to confine the sliding displacement within an acceptable range, while keeping the transfer of seismic force to a minimum to obtain the best isolation performance. This is the advantage of the hybrid sliding isolation system that cannot be achieved by the passive sliding system. Instantaneous optimal control and bang-bang control algorithms are developed for controlling the friction force, since standard control theory is difficult to apply in a straightforward fashion in this case where the control force has a nonlinear feature. The effectiveness of the algorithms in controlling seismic response of a structural model is demonstrated by shaking table experiments and computer simulation. A hybrid sliding isolation system using friction controllable bearings is physically developed, and shaking table experiments are performed using a rigid structural model equipped with such a hybrid system. The dynamic characteristics of the control system for bearing pressure and sliding friction is identified, and the advantage of the hybrid sliding isolation system over the passive system is demonstrated by experiments. Computer codes for simulation of structural response under passive or hybrid control are developed. The numerically simulated results show good agreement with the experimental results, verifying that the analytical model developed represents the actual system very well. Both experimental and analytical studies demonstrate the effectiveness of the hybrid sliding isolation system and suggest its advantageous use in civil structures (AU)

A hybrid sliding isolation system for bridges

This study deals with a hybrid isolation system using friction controllable sliding bearings. During earthquakes, this isolation system controls the friction force on the sliding interface between the structure and the ground to confine the aliding displacement within an acceptable range, while keeping the transfer of seismic force to a minimum. This is the advantage of the hybrid sliding isolation system that can not be duplicated by the passive sliding system. Instantaneous optimal control and bang-bang control algorithms are developed for controlling the friction force. Shaking table tests are perfomed using a bridge model equipped with such a hybrid isolation system. Computer simulations show good agreement with the experimental results, demonstrating the effectiveness of the hybrid sliding control system and the feasibility of its applications for bridges.(AU)