Pressure-Induced Variations of Aggregation Structures in Colorless and Transparent Polyimide Films Analyzed by Optical Microscopy, UV-Vis Absorption, and Fluorescence Spectroscopy.

Pressure-induced variations in the main chain and aggregation structures of colorless and transparent semialiphatic polyimide (PI) films were investigated by optical microscopy, UV-vis absorption, and fluorescence spectroscopy up to 8 GPa. Upon application of pressures up to 2 GPa, a gradual volumetric compression was clearly observed by microscopy, and definite bathochromic shifts of locally excited (LE) absorption bands were detected, which was attributed to the compression of interchain free volume and enhanced intermolecular interactions. In addition, a significant reduction in fluorescence intensity was observed for PIs with quasilinear structures below 2 GPa due to enhanced energy transfer in the excited states caused by the densification of PI chain packing. In contrast, the volumetric compression of the PI films and bathochromic shifts of the LE absorption bands were gradually reduced at pressures above 2 GPa. The former is closely correlated with the bulkiness and flexibility of the alicyclic diamine structure. The latter reflects the intense compression stress generated around the dianhydride moiety, associated with the deformability and in-plane orientation of the main PI chains. High-pressure experiments on PI films are beneficial to investigate variations in aggregation structures and local electronic structures of PI chains induced by dense molecular packing and enhanced intermolecular interactions.

[Surveillance of Chromium(VI) Concentrations in Mineral Water Products].

We developed and evaluated a method of quantifying chromium(VI) in mineral water (MW). After a performance evaluation, we performed a surveillance of chromium(VI) concentrations in 150 kinds of MW products purchased from markets in 2016. Recovery rates, as examined by using 150 spiked samples prepared from the purchased MW products, ranged from 93 to 107%. These results strongly suggest that the validated method is suitable for quantifying chromium(VI) in MW. Chromium(VI) was detected in 65 kinds of MW products; the detection rate was 43%. The minimum concentration of chromium(VI) was 0.0001 mg/L and the maximum was 0.0019 mg/L. The median value of chromium(VI) concentration was 0.0003 mg/L. In most of the products in which chromium(VI) was detected, the concentration ranged from 0.0001 to 0.0002 mg/L. No products were found with concentrations higher than the value (0.05 mg/L) set by the Food Sanitation Law as the specification for MW.

[Development and Applicability of Analytical Methods for Quantifying Cyanide and Bromic Acid in Mineral Waters].

We developed and evaluated methods of quantifying cyanide (cyanide ion and cyanogen chloride) and bromic acid in mineral waters (MW). After performance evaluation, recovery studies were performed on 110 kinds of MW products to examine the applicability of the methods. The approximate proportion of the MW samples, in which the recovery rate of these anionic compounds was within 90 to 110%, was 95% in the cyanide ion and bromic acid analysis and 45% in the cyanogen chloride analysis. We observed low rates of recovery of cyanogen chloride from some MW products with pH values around neutral. To increase the recovery rate, we propose adding phosphoric acid buffer to adjust the pH of these MW samples. The retention times for bromic acid in some MW products differed from that in standard solution. We concluded that carbonic acid influences the retention times. It may be necessary to to exclude carbon dioxide from the MW samples by degassing to synchronize the retention times of bromic acid in the MW samples and the standard solution.

Coffee and beverages are the major contributors to polyphenol consumption from food and beverages in Japanese middle-aged women.

Food and beverages rich in polyphenols have been shown to reduce the risk of non-communicable diseases. The present study estimated polyphenol levels and consumption from food and beverages in Japanese women. Randomly recruited housewives living in the area around Tokyo (n 109; aged 21-56 years; Group 1) recorded all beverages and foods they ingested for 7 d, and the total polyphenol (TP) consumption was estimated based on the TP content of each item measured with a modified Folin-Ciocalteu method. For Group 1, TP was consumed at 841 (sd 403) mg/d (range 113-1759 mg/d), and beverages were a larger source of TP (79 %) than food (21 %). The largest single source of TP was coffee at 47 %, followed by green tea, black tea, chocolate, beer and soya sauce, at 16, 5·7, 3·3, 3·2 and 3·1 %, respectively. In terms of food groups, cereals/noodles, vegetables, fruits, beans and seeds, and seasonings (except for soya sauce) contributed 5·0, 4·0, 1·4, 1·8 and 2·4 %, respectively. Another group of housewives who consumed at least one cup of coffee per d were separately recruited (n 100; Group 2) in the same area. Their consumption of TP was higher at 1187 (sd 371) mg/d (range 440-2435 mg/d) than Group 1 (P < 0·001), and the difference mostly came from the coffee consumption. We conclude that not food but beverages, especially coffee, may be the major contributor to TP consumption in Japanese women.