We investigate the solar cycle variation of microwave and extreme ultraviolet (EUV) intensity in latitude to compare microwave polar brightening (MPB) with the EUV polar coronal hole (CH). For this study, we used the full-sun images observed in 17 GHz of the Nobeyama Radioheliograph from 1992 July to 2016 November and in two EUV channels of the Atmospheric Imaging Assembly (AIA) 193 A° and 171 A° on the Solar Dynamics Observatory (SDO) from 2011 January to 2016 November. As a result, we found that the polar intensity in EUV is anti-correlated with the polar intensity in microwave. Since the depression of EUV intensity in the pole is mostly owing to the CH appearance and continuation there, the anti-correlation in the intensity implies the intimate association between the polar CH and the MPB. Considering the report of Gopalswamy et al. (1999) that the enhanced microwave brightness in the CH is seen above the enhanced photospheric magnetic field, we suggest that the pole area during the solar minimum has a stronger magnetic field than the quiet sun level and such a strong field in the pole results in the formation of the polar CH. The emission mechanism of the MPB and the physical link with the polar CH are not still fully understood. It is necessary to investigate the MPB using high resolution microwave imaging data, which can be obtained by the high performance large-array radio observatories such as the ALMA project.

The interest in the role of antioxidants in human health has prompted research in the fields of food science and horticulture to assess fruit and vegetable antioxidants such as ascorbic acid, anthocyanin, flavonoid, phenolic compounds, and total antioxidant activity. Free radicals have been known to cause degenerative diseases: cardiovascular disease, cancer, diabetes, and brain dysfunction. In this study, five cultivars of blueberries (Nelson, Duke, Bluejay, Toro, and Eliot) were harvested in two different maturity stages (unripe and ripe) to evaluate antioxidant activities and anti-dementia activities. Total phenolics and flavonoids of blueberries inthe ripe stage were higher than those in the unripe stage; alsothe total anthocyanin contentswere much higher in ripe fruits thanin unripe fruits. Antioxidant activities of ripen blueberries were greater than unripe fruits, especially; ‘Nelson’ and ‘Toro’ were higher than other cultivars. Total antioxidant activity was highly correlated with total flavonoids (r=0.8568) and phenolics (r=0.9637). However, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition of blueberries showed that unripe fruits were significantly higher than ripe fruits. In conclusion, there were several differences in antioxidant activities and anti-dementia activities of blueberry depending on fruit cultivars and the maturity stage at harvest. Therefore, unripe fruits also have potential health promoting bioactive compounds as a functional foodingredient.