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To create a new flyable detonation propulsion system, a detonation engine system (DES) that can be stowed in sounding rocket S-520-31 has been developed. This paper focused on the first flight demonstration in the space environment of a DES-integrated rotating detonation engine (RDE) using S-520-31. The flight result was compared with ground-test data to validate its performance. In the flight experiment, the stable combustion of the annulus RDE with a plug-shaped inner nozzle was observed by onboard digital and analog cameras. With a time-averaged mass flow of [Formula: see text] and an equivalence ratio of [Formula: see text], the RDE generated a time-averaged thrust of 518 N and a specific impulse of [Formula: see text], which is almost identical to the ideal value of constant pressure combustion. Due to the RDE combustion, the angular velocity increased by [Formula: see text] in total, and the time-averaged torque from the rotational component of the exhaust during 6 s of operation was [Formula: see text]. The high-frequency sampling data identified the detonation frequency during the recorded time as 20 kHz in the flight, which was confirmed by the DES ground test through high-frequency sampling data analysis and high-speed video imaging.

A detonation engine system is successfully demonstrated for the first time in space using sounding rocket S-520-31 of the Japan Aerospace Exploration Agency/Institute of Space Astronautical Science. Detailed flight results of an S-shaped pulse detonation engine (PDE) installed in the rocket are presented herein. The flight is conducted to confirm that the PDE and its system operate at scheduled sequences in space, confirm the reproducibility of the PDE cycle, and despin the rocket around its axis. It is confirmed that the PDE operated successfully for 14 cycles in space. The experimental plateau pressure of [Formula: see text] is [Formula: see text] of the calculated plateau pressure, which suggests that detonation occurred in 14 cycles. The pressure profiles of the cycles are similar, and the pressure integrals are [Formula: see text], confirming the excellent reproducibility of the PDE cycle. A probability statistical approach assuming a Gaussian distribution is applied to determine the average angular acceleration difference between processes of the PDE operation, mixture supply, and oxygen supply. The results suggested that the PDE despun the rocket via the thrust produced via detonation combustion, which is consistent with a quasi-steady-state model with an accuracy of [Formula: see text].

Henoch-Schönlein purpura nephritis often resolves spontaneously, without treatment, making decisions regarding therapeutic interventions difficult.Fifty-four patients who were diagnosed as having Henoch-Schönlein purpura nephritis between April 2004 and March 2018, and developed hematuria and/or proteinuria, were studied retrospectively. The observation period ended at the disappearance of hematuria or proteinuria, or the last observation date before December 2019 for each patient. Twenty-four of the patients received no treatment (Group A), 19 underwent renin-angiotensin-aldosterone system inhibitors only (B), 4 experienced steroid pulse therapy and combination therapy only (C) and the remaining 7 received steroid pulse therapy and combination therapy following renin-angiotensin-aldosterone system inhibitors (C). Clinical characteristics were examined according to the treatment method. Survival analysis for persistent urinary abnormalities was performed according to treatment modality, with multiple treatment records created per subject, if necessary.The highest urine protein/creatinine levels were significantly higher in groups B and C than in group A. The lowest estimated glomerular filtration rate was not significantly different among the three groups. In groups A and B, proteinuria resolved in90% of patients. Survival analysis showed that steroid pulse therapy and combination therapy was not related to the better resolution of hematuria or proteinuria than renin-angiotensin-aldosterone system inhibitors.Several patients with Henoch-Schönlein purpura nephritis went into remission either without treatment or with renin-angiotensin-aldosterone system inhibitors alone. The treatment plan for patients with Henoch-Schönlein purpura nephritis needs to be determined carefully.

Background and objectives Upper urinary tract infection is the most common serious bacterial infection in childhood. Patients with upper urinary tract infection have a risk for renal scarring with subsequent complications including hypertension, proteinuria, and progressive renal failure. However, the predictive biomarkers of renal scarring in children with upper urinary tract infection are still unknown. In this study, we evaluated whether soluble ST2 levels can be biomarkers of subsequent renal scarring in patients with upper urinary tract infection. Design, setting, participants, and measurements We retrospectively studied pediatric patients with upper urinary tract infection at a tertiary center. Twenty-eight children had an upper urinary tract infection with (n = 14) and without (n = 14) renal scarring and underwent 99mtechnetium dimercaptosuccinic acid imaging. In addition, 13 control subjects were enrolled. The clinical data and serum cytokine levels, including soluble ST2 levels, were compared between those with and without renal scars. Results Serum soluble ST2 levels were significantly higher in the scar group than in the non-scar group, whereas there was no difference in the levels of serum interferon-γ, interleukin-6, interleukin-10, soluble tumor necrosis factor receptor 1, and transforming growth factor-β between the scar and non-scar groups. The area under the curve for differentiating between the non-scar and scar groups on the basis of measurements of serum soluble ST2 was 0.79, with a sensitivity and specificity of 92.9% and 64.3%, respectively. Conclusion These results suggest that serum soluble ST2 levels on admission could be a useful biomarker of subsequent renal scarring in pediatric patients with upper urinary tract infection.

BackgroundPlastic bronchitis (PB) combined with nephrotic syndrome (NS) is rare, and the pathophysiological relationship between PB and NS has not been elucidated. We report a case of an 8-year-old boy with life-threatening PB caused by an influenza infection during a relapse of NS. Case presentationThe patient was on immunosuppressive drugs for NS. He developed fever due to an influenza A virus infection, followed by respiratory distress and frequent vomiting. Prednisolone was administered for possible bronchial asthma and NS. His respiratory status deteriorated rapidly, which required ventilator management. A large mucus plug was aspirated using bronchoscopy. He was then diagnosed with PB caused by the influenza A virus. Increased lower airway secretion and fluid leakage into the airways by relapse of NS were considered the causes of mucus plug formation. Besides, the decreased circulating blood volume might have made the bronchial secretions viscous with cast formation.ConclusionsPediatric patients with NS may be at a higher risk of developing PB. As PB is a life-threatening condition, patients with NS should be closely monitored when simultaneously infected with influenza virus.