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A new measurement technique to reconstruct the density field of the shock-wave/boundary-layer interaction (SWBLI) in a confined duct is proposed. With this technique, it is possible to quantitatively capture in detail the structures of the density field both in the regions of the shock-systems in the central core and boundary-layer flows near the duct wall concurrently. The novel feature of the proposed technique is to make use of the schlieren images with the rainbow filters of the vertical and horizontal cutoff settings and then to reconstruct the two-dimensional density field integrated over the line-of-sight direction using the corresponding filter calibration curves. The proposed technique is applied for the first time to a shock train in a constant-area straight duct under the upstream condition of the shock train: the freestream Mach number is 1.42, the incoming boundary layer thickness normalised by the duct half height is 0.175, and the corresponding unit Reynolds number $Re/m$ is $2.99 \times 10^7$ m-1. The calculated isopycnic field depicts the streamwise and transverse density variations inside the shock train, the mixing region after the shock train, and the boundary-layer of the interaction region. This technique is shown to be capable of identifying the locations of shocks in a shock train more precisely than a conventional approach measuring the static pressure distribution along the duct wall. In addition, various quantitative visual representations such as a shadowgraphy and a bright-field schlieren can be extracted from the density field acquired by the present approach, and the spatial evolution of the shape and strength of each shock constituting the shock train as well as the boundary layer flow properties can be quantitatively clarified. [ABSTRACT FROM AUTHOR]

Systém Mach-Zehnderova interferometru kombinovaný s vysokorychlostní kamerou se aplikuje na řetězec rázu („shock train“) konstantním přímém kanálu pro vyjasnění jeho nestabilní charakteristiky, kde je Machovo číslo 1,44, Reynoldsovo číslo je 4,97 x 107 m-1 a tloušťka hraniční vrstvy je 0,472 mm. Okamžitého dvojrozměrného hustotního pole v řetězci rázu je kvantitativně dosaženo s vysokým prostorovým rozlišením. Současný Mach-Zehnderův interferometrický systém se jeví jako účinný pro měření nestálé hustoty v rázově dominantních proudech v dvojrozměrném kanálu. Oscilační charakteristika každého rázu v rázovém řetězci je demonstrována výkonovou spektrální analýzou pole nestálé hustoty.

The slightly underexpanded free jet issued from a supersonic micro nozzle with a design Mach number of 1.5 and a square shape of 1 mm × 1 mm at the nozzle exit has been experimentally investigated using the rainbow schlieren deflectometry combined with the computed tomography where the nozzle operating pressure ratio is held constant at 4.0. Density fields in the free jet obtained from the rainbow schlieren deflectometry are the vortex sheet theory proposed by Tam. It is shown that there is good quantitative agreement between experiment and theory. It is shown that the rainbow schlieren deflectometry is a useful tool for studying the three-dimensional structure of shock containing free jets from micro-scale supersonic nozzles.

The rainbow schlieren deflectometry is effective in studying quantitatively the density fields in shock-containing free jets at high precision and high spatial resolution. However, there has been no practical application of rainbow schlieren deflectometry for shock trains in a confined duct. Therefore, in the present study, the rainbow schlieren deflectometry is applied to the flow field including a shock train in a constant-area duct where just upstream of the shock train the freestream Mach number is 1.34, the unit Reynolds number is 5.39 × 107 m-1, and the boundary layer displacement thickness is 0.149 mm. As a result, a two- dimensional density field of the shock train is for the first time quantitatively displayed and the fine structure of the shock train is illustrated as a color gradation representation.

Some reports suggest that coronavirus disease 2019 (COVID-19) may affect male reproductive function. There is also concern in Japan that COVID-19 may contribute to the pre-existing decline in male fertility; however, no studies have investigated the effects of COVID-19 on male reproductive function. In this study, we aimed to analyze the semen quality of men who had recovered from COVID-19. Male patients who had recovered from COVID-19 between February 2020 and September 2021 were recruited for this study. Participants were sent a semen collection kit; they were asked to collect semen at home and deliver it to a laboratory at Osaka University. We used these samples to analyze sperm concentration, total sperm count, and semen volume. In total, 125 participants were included in this study. The median age of all patients was 46 years (interquartile range (IQR): 38-52 years). The severity of COVID-19 was mild in 80 patients; 19 were moderate I, 22 were moderate II, and four were severe. The median semen volume was 2.5 mL (IQR: 1.8-3.1), the median sperm concentration was 98.9 million/mL (IQR: 43.8-162.2), and the median total sperm count was 212.1 million (IQR: 89.7-368.2). In a previous study in Japan, the median sperm count in adult men was reported to be 201 million. Participants in our study did not have lower sperm counts than this, despite their older age. Our results suggest that the long-term effects of COVID-19 on spermatogenesis are minimal., Competing Interests: Declarations of competing interest None., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

The symptoms that persist after an acute coronavirus disease 2019 (COVID-19) are referred to as post- COVID conditions. Although the cause of post-COVID conditions remains unclear, the host immune response to SARS-CoV-2 may be involved. Hence, we aimed to investigate the effect of serum antibody titers against SARS-CoV-2 on the development of post-COVID conditions. We conducted a retrospective observational study of COVID-19-recovered individuals who attended the clinic at the National Center for Global Health and Medicine between January 2020 and April 2021. Serum SARS-CoV-2 anti-spike antibody titers were measured and a questionnaire survey was used to collect information on the presence of post-COVID conditions and demographic characteristics of the participants. Participants were then divided into two groups: high peak antibody titer group [≥ 0.759 OD450 value], and low peak antibody titer group [< 0.759 OD450 value] and compared their frequency of post-COVID conditions. Of 526 individuals attending the clinic, 457 (86.9%) responded to the questionnaire. We analyzed the data of 227 (49.7%) participants with measurements of serum antibody titers during the peak period. The incidence of depressed mood was significantly higher in the group with higher antibody titers (odds ratio: 2.34, 95% CI: 1.17-4.67, p = 0.016). There was no significant difference in the frequency of the remaining symptoms between the two groups. Among post-COVID conditions, the depressed mood was more frequent in the group with high serum antibody titers which suggests a difference in pathogenesis between depressive mood and other post-COVID conditions that requires further investigation., Competing Interests: The authors have no conflicts of interest to disclose., (2023, National Center for Global Health and Medicine.)

Objectives: The COVID-19 pandemic has had variable effects on the rates of STIs reported across the globe. This study sought to assess how the number of STI reports changed during the pandemic in Japan., Methods: We used national infectious disease surveillance data from the National Institute of Infectious Diseases (Tokyo, Japan) for the period between January 2013 and December 2021. We compared reported rates of chlamydia, gonorrhoea, condyloma acuminata and genital herpes, as well as total notifications for HIV/AIDS and syphilis during the pandemic versus previous years in Japan. We used a quasi-Poisson regression to determine whether any given week or month between January 2018 and December 2021 had a significant excess or deficit of STIs. Notification values above or below the 95% upper and lower prediction thresholds were considered as statistically significant. The start of the pandemic was defined as January 2020., Results: Chlamydia generally remained within predicted range during the pandemic period. Reporting of gonorrhoea was significantly higher than expected throughout early-to-mid 2021 but otherwise generally remained within predicted range prior to 2021. Condyloma, herpes and HIV/AIDS reporting were transiently significantly lower than expected throughout the pandemic period, but no significant periods of higher-than-expected reporting were detected. Syphilis showed widespread evidence of significantly lower-than-predicted reporting throughout 2020 but eventually reversed, showing significantly higher-than-predicted reporting in mid-to-late 2021., Conclusions: The COVID-19 pandemic was associated with variable changes in the reporting of STIs in Japan. Higher-than-predicted reporting was more likely to be observed in the later phases of the pandemic. These changes may have been attributable to pandemic-related changes in sexual behaviour and decreased STI clinic attendance and testing, but further research on the long-term impact of the pandemic on STIs is necessary., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Anterior nasal sampling (AN) might be more convenient for patients than NP sampling to diagnose coronavirus disease. This study investigated the feasibility of rapid antigen tests for AN sampling, and the factors affecting the test accuracy., Methods: This single-center prospective study evaluated one qualitative (ESP) and two quantitative (LUMI and LUMI-P) rapid antigen tests using AN and NP swabs. Symptomatic patients aged 20 years or older, who were considered eligible for reverse-transcription quantitative polymerase chain reaction using NP samples within 9 days of onset were recruited. Sensitivity, specificity, and positive and negative concordance rates between AN and NP samples were assessed for the rapid antigen tests. We investigated the characteristics that affected the concordance between AN and NP sampling results., Results: A total of 128 cases were recruited, including 28 positive samples and 96 negative samples. The sensitivity and specificity of AN samples using ESP were 0.81 and 1.00, while those of NP samples were 0.94 and 1.00. The sensitivity of AN and NP samples was 0.91 and 0.97, respectively, and specificity was 1.00, for both LUMI and LUMI-P. The positive concordance rates of AN to NP sampling were 0.87, 0.94, and 0.85 for ESP, LUMI, and LUMI-P, respectively. No factor had a significant effect on the concordance between the sampling methods., Conclusions: ESP, LUMI, and LUMI-P showed practical diagnostic accuracy for AN sampling compared to NP sampling. There was no significant factor affecting the concordance between AN and NP sampling for these rapid antigen tests., Competing Interests: Declaration of competing interest K.Yamamoto received research grants from Fujirebio Inc. for their submitted work, and received research grants from Mizuho Medy, Co., Ltd., and VisGene Inc., outside the submitted work. S. Yagi, H. Nojima, and K. Yamakawa are employees of Fujirebio Inc. N. Ohmagari received grants from Sanofi K.K., Japan, and Eiken Chemical Co. Ltd., Japan, outside the submitted work., (Copyright © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

In patients with severe coronavirus disease 2019 (COVID-19) with diabetes, glycemic control is essential for a better outcome, however, we face difficulty controlling hyperglycemia induced by high-dose glucocorticoids. We report five cases of severe COVID-19 patients with diabetes, whose glycemic control was managed using an intermittently scanned continuous glucose monitoring (isCGM) system during methylprednisolone therapy. Patients using isCGM showed significantly lower average blood glucose levels and significantly higher total daily insulin dose during the methylprednisolone therapy, compared to patients under regular blood glucose monitoring. The use of isCGM enables remote glucose monitoring, and this can reduce the risks of healthcare workers who have frequent contact with the patients. Thus, we suggest that using isCGM should be considered in hospitalized patients with diabetes under the COVID-19 pandemic to achieve better glycemic control and to minimize the possible risks of healthcare workers., Competing Interests: The authors have no conflicts of interest to disclose., (2022, National Center for Global Health and Medicine.)

Background: Cerebral syphilitic gummas are rare. However, numerous case reports on them have been published recently, consistent with the resurgence of syphilis and its accompanying atypical manifestations. We here present a patient with a cerebral syphilitic gumma and an unusual clinical course and review recent case reports., Case Presentation: A 49-year-old woman had a generalised seizure and was found by computed tomography and magnetic resonance imaging to have a brain mass that mimicked a brain abscess or malignant tumour. Further imaging with magnetic resonance spectroscopy and positron emission tomography did not contribute further to the differential diagnosis. Because treatment with ceftriaxone was ineffective, the lesion was resected. Serological tests on serum and cerebrospinal fluid were positive for syphilis and histopathological examination of the operative specimen revealed a syphilitic gumma. Antibiotic treatment is preferred over invasive interventions for cerebral syphilitic gumma. However, as in our case, radical resection is required when antibiotic treatment is ineffective., Conclusions: It has recently been reported that the prevalence of syphilis is increasing in older individuals, including in patients without HIV infection or prior treatment for early syphilis. Though advanced imaging and molecular biological techniques are often used to help make a diagnosis, they are of limited value. Because the clinical and imaging features are nonspecific, some neurosurgeons do not include cerebral syphilitic gummas in their differential diagnoses. It is vital that this possibility be considered when a patient has a tumour-like cerebral mass and serum positivity for syphilis.

We herein report a case of cerebral infarct in a patient with coronavirus disease 2019 (COVID-19) infection who died of aspiration pneumonia. The postmortem examination of the brain revealed embolic infarct with negative findings on quantitative reverse transcription polymerase chain reaction (qRT-PCR) as well as immunohistochemistry to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The systemic examination only revealed low copy numbers of SARS-CoV-2 in the bronchus. This is the first and so far only autopsy case of COVID-19 infection with pathologic and virologic findings of the postmortem brain in Japan.

Background: Polymyxin E (colistin) is a last-resort antibiotic to treat infections caused by carbapenemase-producing Enterobacteriaceae (CPE). However, reports of CPEs resistant to colistin have been increasing, and the mcr genes are emerging as resistance mechanisms. Among them, plasmid-mediate mcr-9 is known to be associated with colistin resistance, whereas reports on chromosomal mcr-9 and its association with colistin resistance in humans are few., Case Presentation: We identified Enterobacter asburiae harboring mcr-9 and bla IMP-60 in the pleural fluid of a patient with empyema. The long-read sequencing technique revealed that these genes were located on its chromosome. Despite the lack of exposure to colistin, the organism showed microcolonies in the inhibition circle in the E-test and disk diffusion test. Antibiotic susceptibility testing by broth microdilution confirmed its resistance to colistin., Conclusion: Our case report showed that mcr-9 can be present not only on plasmids but also on the chromosome in E. asburiae, and that the presence of mcr-9 on its chromosome may influence its susceptibility to colistin., (© 2022. The Author(s).)

Introduction: The post-COVID condition has become a social concern. Although the patient characteristics associated with the development of this condition are partially known, those associated with its persistence have not been identified., Methods: We conducted a cross-sectional questionnaire-based survey among patients who had recovered from COVID-19 and visited the National Center for Global Health and Medicine between February 2021 and March 2021. Demographic and clinical data, and data regarding the presence and duration of post-COVID conditions were obtained. We identified factors associated with the development and persistence of post-COVID conditions using multivariate logistic and linear regression analyses, respectively., Results: We analyzed 457 of 526 responses (response rate, 86.9%). The median patient age was 47 years. Of these, 378 patients (84.4%) had mild disease in the acute phase. The number of patients with symptoms at 6 and 12 months after onset or diagnosis was 120 (26.3%) and 40 (8.8%), respectively. Women were at risk of developing fatigue (odds ratio [OR]: 2.03, 95% confidence interval [CI]: 1.31-3.14), dysosmia (OR: 1.91, 95%CI: 1.24-2.93), dysgeusia (OR: 1.56, 95%CI: 1.02-2.39), hair loss (OR: 3.00, 95%CI: 1.77-5.09), and persistence of any symptoms (coefficient: 38.0, 95%CI: 13.3-62.8). Younger age and low body mass index were factors for developing dysosmia (OR: 0.96, 95%CI: 0.94-0.98 and OR: 0.94, 95%CI: 0.89-0.99, respectively) and dysgeusia (OR: 0.98, 95%CI: 0.96-1.00 and OR: 0.93, 95%CI: 0.88-0.98, respectively)., Conclusion: We identified factors involved in the development and persistence of post-COVID conditions. Many patients, even those with mild conditions, experience long-term residual symptoms., (Copyright © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)