Spin-dependent recombination of photoinduced carriers in H 2 -phthalocyanine (H 2 Pc͒/C 60 heterojunctions is studied by electrically detected electron-spin resonance ͑EDESR͒ spectroscopy. The EDESR spectrum of the H 2 Pc/C 60 consists of two components A and B, the g values of which are 2.0018Ϯ0.0002 and 2.0010Ϯ0.0002, respectively. The two components are attributed to exchange-coupled localized electron-hole pairs trapped at different types of recombination centers. Component A has spin-flip satellites due to an interaction between the electron ͑or hole͒ spin, and its surrounding nuclear spins of protons which belong to the H 2 Pc rings. From the satellite intensity, the distance between the electron ͑or hole͒ and the protons is estimated to be 4.33Ϯ0.25 Å, indicating that the localized pairs for the component A locate close to the H 2 Pc rings. The spin dynamics of the localized pairs for the component A is studied by a microwave recovery experiment, in which the time dependence of the EDESR signal intensity is measured after turning the resonant microwave on and off. A theoretical model of the spin-dependent recombination of the exchange-coupled electron-hole pair is proposed with which the experimental results of the microwave recovery are explained. By a theoretical analysis, it is found that Rտ1ϫ10 6 s Ϫ1 and DϩW sl ϭ6.2 (Ϯ0.8)ϫ10 4 s Ϫ1 for component A at room temperature, where R is the recombination rate of the localized pair in the S z ϭ0 triplet sublevel, and D and W sl are the dissociation and the spin-lattice relaxation rates, respectively, of the pairs in the triplet sublevels. The photocurrent I 2 that is caused by the dissociation of the localized pairs for component A is about 5% of the total photocurrent.
Summary As bioactive ingredients of functional foods, dietary fiber and wheat albumin (WA) are known to suppress hyperglycemia in patients with type 2 diabetes mellitus. The combined effects of these bioactive ingredients were examined using an animal model of type 2 diabetes mellitus. First, oral starch tolerance tests (OSTTs) with the simultaneous intake of a dietary fiber mixture (DF) and WA were performed as an acute study. Male GotoKakizaki rats received a soluble starch solution [700 mg/kg body weight (bw)] containing DF and/or WA (each 300 mg/kg bw). In these OSTTs, the combined intake of DF and WA suppressed hyperglycemia much more effectively than each separate intake. Second, in a chronic intake study, diets containing DF and/or WA were administered to male Zucker diabetic fatty rats over 84 d. The combined effects of DF and WA were not observed in glycosylated hemoglobin concentration levels or fasting blood glucose levels, but appeared as an improvement in liver lipid contents. Variations in the liver lipid contents were similarly reflected in those of the plasma lipid concentrations. In conclusion, this study found that the simultaneous intake of bioactive DF and WA improved the postprandial hyperglycemia and the chronic lipid metabolism disorders in rat models of type 2 diabetes mellitus. Key Words type 2 diabetes mellitus, dietary fiber, wheat albumin, combined effect, lipid metabolism disorderIn type 2 diabetes mellitus, postprandial hyperglycemia caused by a lack of prompt insulin secretion is closely associated with insulin resistance and thus hyperglycemia, which leads to a lipid metabolism disorder that results in arteriosclerosis (1-3). Some dietary fiber, such as water-soluble dietary fiber, physically retards the absorption of glucide and suppresses postprandial hyperglycemia (4). In Japan, therefore, the dietary fibers extracted mostly from various plants are used as functional ingredients of foods. On the other hand, wheat albumin (WA), based on the action of its principle component 0.19-albumin (termed by its electrophoretic mobility), inhibits mammalian amylase (5, 6), delays glucide digestion in vivo, and suppresses postprandial hyperglycemia (7). Thus, WA is widely distributed as a bioactive ingredient of food for specified health uses (FOSHU) in the market. Various consumers, intentionally or unintentionally take simultaneously more than two of these functional ingredients in foods. However, the combined effects of dietary fiber and WA on the postprandial hyperglycemia and also on chronic glucide and lipid metabolism are unknown. Here the simultaneous intake of these ingredients was examined using a rat model of type 2 diabetes mellitus. MATERIALS AND METHODSApproval and feeding conditions. All rats were maintained under standard conditions of 2362˚C and 55615% humidity with a 12 h/12 h light/dark cycle. The rats were individually housed in clean cages with free access to water and basal diet (CLEA rodent diet CE-2; CLEA Japan, Inc., Tokyo, Japan) ad libitum during the acclimation p...
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