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The Mn doping effects on the electric and dielectric properties of ZnO epitaxial films were studied. To optimize the stoichiometry of undoped ZnO film prepared by pulsed laser deposition, we evaluated the intensity ratio of the optical emission from excited oxygen atoms (O*) and excited zinc atoms (Zn*) generated by ablating a ZnO ceramic target in plume. The leakage current of undoped ZnO film decreased with an increase of the ratio I(O777*)/I(Zn335*). Mn doping of ZnO was also effective in decreasing the leakage current. The ZnO:4 at. % Mn had a very small leakage current, eight orders of magnitude less than that of undoped ZnO. With a Mn concentration above 4 at. %, on the other hand, the leakage current was increased. The activation energy in ZnO:Mn obtained from the temperature dependence of the ac conductivity revealed that oxygen vacancy was responsible for the large current at the Mn concentration below 2 at. %. For the sample with the Mn concentration of 2–3 at. %, dominant conduction in ZnO:Mn epitaxial films originated from the interstitial Zn. When the Mn concentration was above 4 at. %, the conduction was governed by the substitution of Zn atoms in the oxygen site. Impedance analysis revealed that the origin for large resistivity of ZnO:Mn films was not the ZnO/electrode interface but the bulky part of the films. [ABSTRACT FROM AUTHOR]

This study investigated the influence of antiferromagnetic exchange interaction on magnetic properties of ZnMnO thin films grown on ZnO [formula] single-crystal substrates. Using pulsed laser deposition, ZnMnO films with Mn concentrations as high as 14.1 at. % were prepared. Investigations revealed that the lattice constant along the c axis of the ZnMnO films increases linearly with increasing Mn concentration. The lattice constant along the a axis is independent of the Mn concentration and is equal to that of the ZnO substrate, suggesting pseudomorphic growth of ZnMnO films. An atomic force microscopy image of the ZnMnO film grown at 640 °C shows a step-and-terrace structure. An interference fringe around the ZnMnO 0004 symmetric diffraction image is clearly visible in the 2θ-ω x-ray diffraction profile, suggesting that the samples have a smooth surface and an abrupt interface. The intrinsic magnetic properties of these pseudomorphically grown ZnMnO films with smooth surfaces were evaluated. At temperatures greater than 1.85 K, ZnMnO films with Mn concentration up to 14.1 at. % exhibit typical paramagnetic characteristics. As calculated using the probabilities for a random Mn distribution, the theoretically magnetic moment agreed with the experimentally determined saturated magnetic moment, indicating an antiferromagnetic exchange interaction between the nearest-neighbor Mn ions. [ABSTRACT FROM AUTHOR]

Depression in later life is associated with dementia. Changes in motivated behavior are an important mechanism contributing to dysfunctional cognitive control in depression. Although continuous intake of quercetin-rich onion suppresses cognitive decline in aged people by improving their emotional condition, the effect of quercetin-rich onion on emotional condition in people living with cognitive impairment remains unclear. In this randomized, double-blind, placebo-controlled study of subjects with cognitive impairment, we found that subjects wrote more adjectives and adverbs per sentence on the Mini-Mental State Examination after intake of quercetin-rich onion powder than before intake, although regional cerebral blood flow on n-isopropyl-4-[123]iodoamphetamine hydrochloride single-photon emission computed tomography was not changed. In the EPM, mice that had received a quercetin-supplemented chow diet made a significantly increased number of exploratory head dips from the open arms of the maze. Moreover, the 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl decay rate, reflecting redox activity, was increased in mice fed a quercetin-added diet. These results indicate that quercetin-rich onion may affect motivated behavior in subjects with cognitive impairment, for whom quercetin intake may preserve redox homeostasis in the brain.

The spin-dependent transport property in modulation-doped ZnMnO:Al/ZnMnO/Zno heterostructures is described. The positive magnetoresistance (MR) is well fitted to a Brillouin function, thus showing the existence of an s-d exchange interaction at the ZnMnO/ZnO interface.

A study was conducted to examine the effect of antiferromagnetic exchange interaction on magnetic properties of ZnMnO thin films grown on ZnO (0001) single-crystal substrates. The findings revealed that the lattice constant along the c axis of the ZnMnO films increases linearly with increasing Mn concentration.

Anti-oxidant properties of polyphenols have been gaining medical attention as a preventive factor against aging and/or lifestyle diseases. In this study, we examined the anti-oxidant activity of quercetin improved tear function through its effects on the lacrimal gland in mice and humans. Six week-old diabetic mice, a model for decreased tear production, were fed for 12 weeks ad libitum with an experimental diet containing 0.5% quercetin. As a result, the tear volume was significantly improved compared to the control, despite no changes in body weight, food intake, lacrimal gland morphology or biochemical serum parameters. Moreover, significantly higher SOD-1 and SOD-2 protein levels were detected in the lacrimal glands of quercetin-treated mice by western blot. In addition, quercetin treatment of mouse corneal cell lines exposed to oxidative stress resulted in dose-dependent inhibition of ROS production and enhanced cell survival. Finally, we examined quercetin pharmacokinetics, specifically its presence in serum and tears subsequent to onion consumption in healthy volunteers, and found that the distribution of quercetin and its metabolite shifted from serum to tear following onion intake. An improvement in tear film stability also resulted following the intake by these healthy volunteers of a new, quercetin-rich onion cultivar (”Quergold”) in powder form. These results suggested that quercetin improved tear function through its effects on the lacrimal gland in mice and humans.

In the present research, we investigated changes in the gut metabolome that occurred in response to the administration of the Laticaseibacillus rhamnosus strain GG (LGG). The probiotics were added to the ascending colon region of mature microbial communities established in a human intestinal microbial ecosystem simulator. Shotgun metagenomic sequencing and metabolome analysis suggested that the changes in microbial community composition corresponded with changes to metabolic output, and we can infer linkages between some metabolites and microorganisms. The in vitro method permits a spatially-resolved view of metabolic transformations under human physiological conditions. By this method, we found that tryptophan and tyrosine were mainly produced in the ascending colon region, while their derivatives were detected in the transverse and descending regions, revealing sequential amino acid metabolic pathways along with the colonic tract. The addition of LGG appeared to promote the production of indole propionic acid, which is positively associated with human health. Furthermore, the microbial community responsible for the production of indole propionic acid may be broader than is currently known.

We examine the validity and reproducibility of a food frequency questionnaire (FFQ) in a subsample of participants in the Japan Public Health Center-based Prospective Cohort Study using a database of polyphenol-containing foods commonly consumed in the Japanese population. Participants of the validation study were recruited from two different cohorts. In Cohort I, 215 participants completed a 28-d dietary record (DR) and the FFQ, and in Cohort II, 350 participants completed DRs and the FFQ. The total polyphenol intake estimated from the 28-d DR and FFQ were log-transformed and adjusted for energy intake by the residual method. Spearman correlation coefficients (CCs) between estimates from the FFQ and 28-d DR as well as two FFQs administered at a 1-year interval were computed. Median intakes of dietary polyphenols calculated from the DRs were 1172 mg/d for men and 1024 mg/d for women in Cohort I, and 1061 mg/d for men and 942 mg/d for women in Cohort II. The de-attenuated CCs for polyphenol intake between the DR and FFQ were 0⋅47 for men and 0⋅37 for women in Cohort I and 0⋅44 for men and 0⋅50 for women in Cohort II. Non-alcoholic beverages were the main contributor to total polyphenol intake in both men and women, accounting for 50 % of total polyphenol intake regardless of cohort and gender, followed by alcoholic beverages and seasoning and spices in men, and seasoning and spices, fruits and other vegetables in women. The present study showed that this FFQ had moderate validity and reproducibility and is suitable for use in future epidemiological studies.