Ammonium dichromate and chromium chloride were examined via thermogravimetric and differential thermal analyses and used to grow α-Cr2O3 via mist chemical vapor deposition. Only the former resulted in noticeable film formation. Using ammonium dichromate, α-Cr2O3 single crystals were grown in a wide growth-temperature range of 300–440 °C. The dependences of the lattice constants a and c on the growth temperature and precursor concentration were explained by combination of (i) lattice reconstruction and (ii) unit-cell volume variation. A maximum growth rate of 10 nm/min; a low (0006) rocking-curve full width at half maximum of 150 arcsec; and low a and c lattice mismatches (with α-Ga2O3) of 0.7 and 1.4%, respectively, were achieved.

The coronavirus disease 2019 symptoms in children are relatively mild and often do not require treatment. Nonetheless, complications caused by the immune response to COVID-19 in children are possible and diverse. We present the case of a 7-year-old girl with persistent fever and lymphadenopathy arising from SARS-CoV-2 infection, diagnosed with Kikuchi-Fujimoto Disease (KFD) on lymph node biopsy. KFD is a rare benign disease, clinically characterized by fever and tender cervical lymphadenopathy affecting posterior cervical lymph nodes. We also reviewed six previously reported cases of COVID-19-associated KFD that occurred in school-aged children and compared them with the present case. The clinical course of COVID-19-associated KFD was similar to that of previous reports of KFD with a favorable prognosis. This is the first report of a school-aged child developing KFD following SARS-CoV-2 infection. KFD should be considered when approaching patients with hyperinflammatory states who present with prolonged fever and cervical lymphadenopathy after COVID-19.

Yttrium iron garnet (YIG) thin films were deposited on c-plane sapphire substrates under atmospheric pressure by a mist CVD technique, and their chemical composition and optical properties were examined. The thin films deposited at 450 °C showed an [Y]/[Fe] ratio of 0.57, indicating the deposition of yttrium iron oxide, while the molar ratio of [Y]/[Fe] in the precursor solution was set at 1.5. A thermodynamic model was developed to explain the reaction paths of the YIG thin film fabrication process using thermogravimetric differential thermal analysis (TG-DTA) results. The model indicates that the decomposition rate of yttrium acetylacetonate [Y(acac)3 ∙ nH2O] was much lower than that of iron acetylacetonate [Fe(acac)3], providing a plausible explanation for the large difference between the composition ratio of the thin films and that of the precursor solutions.

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