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Background Methods Results Conclusions The COVID‐19 pandemic has affected the lives of people of all ages. Most reports on pediatric cases suggest that children experience fewer and milder symptoms than do adults. This is the first nationwide study in Japan focusing on pediatric cases reported by pediatricians, including cases with no or mild symptoms.We analyzed the epidemiological and clinical characteristics and transmission patterns of 840 pediatric (<16 years old) COVID‐19 cases reported between February and December 2020 in Japan, using a dedicated database which was maintained voluntarily by members of the Japan Pediatric Society.Almost half of the patients (47.7%) were asymptomatic, while most of the others presented mild symptoms. At the time of admission or first outpatient clinic visit, 84.0% of the cases were afebrile (<37.5°C). In total, 609 cases (72.5%) were exposed to COVID‐19‐positive household members. We analyzed the influence of nationwide school closures that were introduced in March 2020 on COVID‐19 transmission routes among children in Japan. Transmission within households occurred most frequently, with no significant difference between the periods before and after declaring nationwide school closures (70.9% and 74.5%, respectively).COVID‐19 symptoms in children are less severe than those in adults. School closure appeared to have a limited effect on transmission. Controlling household transmission from adult family members is the most important measure for prevention of COVID‐19 among children. [ABSTRACT FROM AUTHOR]

The degree of pore filling is an important parameter for defining guest@MOF properties in applications including electronics, optics, and gas separation. However, the interplay of key aspects of host–guest interactions, such as a quantitative description of the guest alignment or the structural integrity of the host as function of pore filling are yet to be determined. Polarisation‐dependent infrared spectroscopy in attenuated total reflection configuration combined with gas sorption allowed to simultaneously study the orientation of the guest molecule and structural changes of the MOF framework during the pore filling process. Thereby we found, that initially randomly oriented guest molecules align with increasing pore filling during adsorption from the gas phase. At the same time, the framework itself undergoes a reversible, guest molecule‐dependent rotation of the aromatic linker and a linker detachment process, which induce defects. [ABSTRACT FROM AUTHOR]

Der Grad der Porenfüllung definiert die Gast@MOF‐Eigenschaften in Anwendungen wie Elektronik, Optik und Gastrennung. Das Zusammenspiel von Schlüsselaspekten der Wirt‐Gast‐Wechselwirkungen, wie eine quantitative Beschreibung der Gastausrichtung oder die strukturelle Integrität des Wirts als Funktion der Porenfüllung, muss jedoch noch bestimmt werden. Polarisationsabhängige Infrarotspektroskopie in abgeschwächter Totalreflexionskonfiguration in Kombination mit Gassorption ermöglichten es, gleichzeitig die Orientierung des Gastmoleküls und strukturelle Änderungen des MOF‐Gerüsts während des Porenfüllprozesses zu untersuchen. Dabei stellten wir fest, dass sich zunächst zufällig orientierte Gastmoleküle mit zunehmender Porenfüllung während der Adsorption aus der Gasphase ausrichten. Gleichzeitig erfährt das Gerüst selbst eine reversible, vom Gastmolekül abhängige Rotation des aromatischen Liganden und einen Prozess der Ligandenablösung, wodurch Defekte induziert werden. [ABSTRACT FROM AUTHOR]