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Several studies have reported that the pandemic of coronavirus disease 2019 (COVID-19) influenced cognitive function in the elderly. However, the effect of COVID-19-related fear on brain atrophy has not been evaluated. In this study, we evaluated the relation between brain atrophy and the effect of COVID-19-related fear by analysing changes in brain volume over time using magnetic resonance imaging (MRI).
Participants were 25 Japanese patients with mild cognitive impairment (MCI) or subjective cognitive decline (SCD), who underwent 1.5-tesla MRI scan twice, once before and once after the pandemic outbreak of COVID-19, and the Fear of Coronavirus Disease 2019 Scale (FCV-19S) assessment during that period. We computed regional brain atrophy per day between the 1st and 2nd scan, and evaluated the relation between the FCV-19S scores and regional shrinkage.
There was significant positive correlation between the total FCV-19S score and volume reduction per day in the right posterior cingulate cortex. Regarding the subscales of FCV-19S, we found significant positive correlation between factor 2 of the FCV-19S and shrinkage of the right posterior cingulate cortex.
There was positive correlation between the FCV-19S score and regional brain atrophy per day. Although it is already known that the psychological effects surrounding the COVID-19 pandemic cause cognitive function decline, our results further suggest that anxiety and fear related to COVID-19 cause regional brain atrophy.
Although most Kawasaki disease with giant coronary aneurysms is asymptomatic, conventional investigations might not identify previous lesions, or all Kawasaki disease with giant aneurysms at risk of future myocardial lesions. We evaluated the long-term histopathology of the myocardium, especially of intramural small vessels in asymptomatic Kawasaki disease with giant aneurysms.
The initial study comprised 16 consecutive Kawasaki patients – male-to-female ratio was 12:4 – aged from 2 to 12 years, and in the subsequent study, the same patients were aged from 4.9 to 16 years. Endomyocardial biopsies were histopathologically evaluated. Microangiopathies, mitochondrial abnormalities, and loss or disarray of myofibrils were compared by electron microscopy.
The incidence of histopathological abnormalities such as degeneration, hypertrophy, and inflammatory cell infiltration was quite high in the initial study, and inflammatory cell infiltration, interstitial fibrosis, and disarray were very noticeable at follow-up biopsies. The area of fibrous tissue was significantly higher in patients administered with intravenous immunoglobulin at follow-up biopsies. Electron microscopy showed microangiopathies including microthrombi within intramural small vessels in some patients at follow-up biopsies. The sites of the coronary aneurysms did not seem to have an impact on the biopsy findings, suggesting that the underlying pathophysiology is related to the original disease process.
Whether the abnormalities were due to direct myocardial injury, chronic ischaemia, repeated small-vessel thrombosis, or other problems associated only with biopsies, is difficult to determine. However, this subgroup had residual abnormal lesions in the myocardium. Follow-up should be more aggressive in this group of patients to identify myocardial damage that could be asymptomatic.
We have demonstrated that 30BaO–15TiO2–30GeO2–25SiO2 (BTGS25) glass is a candidate for fiber-type nonlinear optical devices using crystallization of glass matrix. We determined the glass composition is suitable for crystallized fiber using partial substitution of Ge in 30BaO–15TiO2–55GeO2 (BTG55) by Si. The BTGS25 satisfied both thermal stability for fiber drawing and electronic polarizability for nonlinear optical property. After crystallization, the BTGS25 bulk crystallized glass showed surface crystallization behavior with the polar c-orientation of fresnoite phase, which was favorable for large second-order optical susceptibility. Following the results of the bulk glass, we prepared the BTGS25 glass fiber without precipitation of fresnoite crystallites. The BTGS25 crystallized fiber also showed c-oriented surface crystallization of fresnoite and second harmonic generation, which shows that the crystallized fiber is a promising material for fiber-type optical active devices.
Triisobutylaluminum (TIBA) was used as an aluminum source for metalorganic molecular beam epitaxy (MOMBE). The optical absorption coefficient for TIBA was found to be larger than both tri ethyl aluminum and triethylgallium. TIBA was introduced into a laser-induced MOMBE system and selective deposition of Al and AlAs was carried out. Al metal was deposited on the area where the ArF excimer laser was irradiated and no deposition was observed without the excimer laser irradiation at a substrate temperature of 350 C. Furthermore, a laser large enhancement of the growth rate of AlAs was observed at 350 C.
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