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To determine annual layers for reconstructing the past environment at annual resolution from ice cores, we employed snow-stake data back to 1972, tritium content, solid electrical conductivity measurements (ECM) and stratigraphic properties for the 73m ice core at the H72 site, east Dronning Maud Land, Antarctica. the average annual surface mass balance at H72 is 307 mma–1w.e. during the last 27 years from continuous accumulation data, 317 mma–1 w.e. according to the densification model and 311 mma–1 w.e. according to the average surface mass balance for 167 years based on annual-layer counting. the ECM age is closely coincident with tritium age, and corresponds with the snow-stake record back to AD 1972 from the surface to 15 m depth. the H72 ice core is dated as AD 1831by ECMat 73.16 mdepth.The time series of yearly surface mass balance at H72 shows an almost constant 311 mm a–1 w.e. for the last 167 years. the oxygen-isotope records indicate a significant trend to lower values, with negative gradient of 1.7% (100 years)–1.
We calculate B-, R- and I-band internal extinction A(λ)i (absorption + scattering) for spirals consisting of an exponential dust layer, a stellar disk and a bulge. The result is applied to local calibrators and cluster spirals (Virgo and Ursa Major) to examine whether or not the wavelength dependence of the relative zero point difference of Tully-Fisher (TF) relations between for local calibrators and for cluster spirals (Pierce & Tully, 1992) could be accounted for by a variation of A(λ)i on the optical depth of galaxies. The extinction is calculated using Monte-Carlo simulations prescribed by Bianchi et al. (1996). For the extinction curve we adopted the one of Cardelli et al. (1989). It is found that a differential extinction A(R or I)i – A(B)i as a function of the optical depth σ(B) has finite upper limits of ∼ 0.3–0.5 mag, depending on an inclination of the spiral. These limits are generally smaller than the offset of the TF relative zero point difference. This indicates that the offset may be fully due to an intrinsic color difference between local calibrators and cluster galaxies, or else that the current extinction model is yet to realize a practical extinction process or geometrical configuration of spirals.
The physicochemical properties of glyme-Li[FSA] (FSA: bis(fluorosulfonyl)amide) equimolar complexes were investigated. The self-diffusion coefficients of glymes and Li+ as determined by pulsed-field gradient spin-echo nuclear magnetic resonance spectroscopy in equimolar complexes were almost identical, suggesting that all of the glyme molecules coordinated with Li+. Electrochemical characterization revealed that the oxidative stability of glyme molecules was enhanced by complexing with Li+. Using [Li(glyme)1][FSA] electrolytes and a LiFePO4cathode, a lithium secondary battery could be stably operated for more than 100 cycles at room temperature.
We propose to use Purcell effect emerged at slow light regions in photonic crystal waveguide (PC-WG) modes for controlling the relaxation time of excited carriers in QDs. Straight GaAs PC-WGs including InAs-QDs with various lattice constants of PC were prepared in order to control the wavelength of the slow light in the PC-WG modes. PL measurements of the PC-WGs indicated enhancements of emission from QDs at the localized wavelength of slow light regions due to the Purcell effect. The enhanced emission peak wavelength was continuously shifted with the PC lattice constant. These results suggest that the PC-WG can be utilized to modify the spontaneous emission rate and carrier relaxation time of the embedded QD. This modification can be applied and useful for various QD-based optical devices as well as our proposed all-optical switching device based on PC-WG/QD.
We have developed a selective-area-growth (SAG) method of self-assembled InAs quantum dots (QDs) using a metal-mask (MM) combined with molecular beam epitaxy for realizing photonic crystal (PC) based ultra-small and ultra-fast all-optical devices (PC-SMZ and PC-FF). Successful SAG of QDs was confirmed by atomic-force-microscopy observations and photoluminescence (PL) measurements. High density and high uniformity comparable to those of conventional QDs grown without the MM were achieved; the QD density was 4 × 1010cm-2 and a linewidth of the PL peak was around 30meV at room temperature. In addition, insertion of a strain-reducing layer on the grown QD was effective for varying the PL peak wavelength of the QD from 1240nm to 1320nm without any extra optical degradation. The MM method reported here is promising for achieving the all optical devices, PC-SMZ and PC-FF, which require SAG of QDs and a QD ensemble with a different absorption-peak wavelength in a different area.
Strategies to manipulate the gut microbiota have been explored for preventing allergy development. We previously showed that dietary supplementation with fructo-oligosaccharide (FOS) reduced 2, 4-dinitrofluorobenzene (DNFB)-induced contact hypersensitivity (CHS) in BALB/c mice. Because the CHS response was negatively correlated with the number of faecal bifidobacteria, particularly Bifidobacterium pseudolongum, the present study aimed to examine whether oral administration of B. pseudolongum affects CHS response. Viable B. pseudolongum was successfully isolated from mouse faeces. Female BALB/c mice were fed a synthetic diet with or without FOS supplementation, and B. pseudolongum (2 × 107 cells) was administered daily throughout the experimental period. Two weeks after starting the test diets, mice received DNFB on the ear auricle twice at 7-d intervals. Conventional cultivation and molecular biological analyses based on 16S rRNA gene sequences showed that administration of FOS and B. pseudolongum resulted in higher excretion of viable bifidobacteria, mainly B. pseudolongum. Although dietary FOS reduced the CHS response as demonstrated by ear swelling, B. pseudolongum administration resulted in a reduction in the initial phase only of the CHS response. B. pseudolongum administration increased hapten-specific IgG1, while dietary FOS decreased IgG2a in sera. Administration of FOS and B. pseudolongum decreased interferon-γ production and increased IL-10 production in cervical lymph node cells restimulated with hapten in vitro. We conclude that B. pseudolongum proliferation in the intestinal tract is partially responsible for the reduction in DNFB-induced CHS response by dietary supplementation with FOS in mice, which may be mediated by the modulation of antigen-induced cytokine production.
Strategies to manipulate the gut microbiota in infancy have been considered to prevent the development of allergic diseases later in life. We aimed to elucidate the effects of maternal dietary supplementation with a prebiotic oligosaccharide on gut microbiota and spontaneously developing atopic dermatitis-like skin lesions in the offspring of NC/Nga mice. Female NC/Nga mice were fed diets either with or without fructo-oligosaccharide supplementation during pregnancy and lactation. After weaning, offspring were fed the diets supplemented with or without fructo-oligosaccharide for 11 weeks in an air-uncontrolled conventional room. Changes in gut microbiota were assessed by denaturing gradient gel electrophoresis of the PCR-amplified 16S rRNA gene. Skin lesions were evaluated by a clinical score and scratching behaviour. Serum antibody levels were measured by ELISA, and expression levels of cytokines and chemokines in lesional tissue were evaluated by quantitative RT-PCR. Maternal supplementation with fructo-oligosaccharide modulated the gut microbiota in sucklings. Although maternal supplementation with fructo-oligosaccharide suppressed the increase in clinical skin severity score and scratching behaviour in offspring, dietary fructo-oligosaccharide after weaning was less effective. The diminution of skin lesions was accompanied by lower serum concentrations of total IgG1 and lower expression levels of TNF-α in the lesional tissue. These data suggest that maternal consumption of fructo-oligosaccharide diminishes the severity of atopic dermatitis-like skin lesions in the offspring of NC/Nga mice.
Our preliminary clinical trial showed that consumption of cooked rice of a Japanese common cultivar Yukihikari improved atopic dermatitis associated with a suspected rice allergy, although the underlying mechanisms remain unclear. We hypothesised that the ameliorating effect of Yukihikari on atopic dermatitis is associated with the gut microbiota. BALB/c mice were fed a synthetic diet supplemented with uncooked and polished white rice powder prepared from one of four different cultivars: Yukihikari, rice A (common rice), rice B (brewery rice) and rice C (waxy rice). Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments showed that the composition of faecal microbiota was different between mice fed Yukihikari and those fed rice A. Analysis of the 16S rRNA clone library and species-specific real-time PCR showed that the abundance of Akkermansia muciniphila, a mucin degrader, tended to be lower in mice fed Yukihikari. The incidence of allergic diarrhoea induced by oral administration of ovalbumin in systemically immunised mice was lower in mice fed Yukihikari, albeit with no difference in serum antibodies specific to ovalbumin. In a separate experiment, serum antibody levels specific to orally administered ovalbumin were lower in mice fed Yukihikari. Additionally, the translocation of horseradish peroxidase in isolated segments of ileum and colon tended to be lower in mice fed Yukihikari, suggesting a reduction in gut permeability in mice fed Yukihikari. These data indicate that changes in the gut microbiota of mice fed Yukihikari could be advantageous in the prevention of food allergy.
The aim of the present study was to examine the effects of cobalamin (Cbl) on the activity and expression of l-methylmalonyl-CoA mutase (MCM) in rat liver and cultured COS-7 cells. The MCM holoenzyme activity was less than 5 % of the total (holoenzyme+apoenzyme) activity in the liver although rats were fed a diet containing sufficient Cbl. When weanling rats were maintained on a Cbl-deficient diet, the holo-MCM activity became almost undetectable at the age of 10 weeks. In contrast, a marked increase in the total-MCM activity occurred under the Cbl-deficient conditions, and at the age of 20 weeks it was about 3-fold higher in the deficient rats than in the controls (108 (sd 14·5) v. 35 (sd 8·5) nmol/mg protein per min (n 5); P < 0·05). Western blot analysis confirmed that the MCM protein level increased significantly in the Cbl-deficient rats. However, the MCM mRNA level, determined by real-time PCR, was rather decreased. When COS-7 cells were cultured in a medium in which 10 % fetal bovine serum was the sole source of Cbl, holo-MCM activity was barely detected. The supplementation of Cbl resulted in a large increase in the holo-MCM activity in the cells, but the activity did not exceed 30 % of the total-MCM activity even in the presence of Cbl at 10 μmol/l. In contrast, the total-MCM activity was significantly decreased by the Cbl supplementation, indicating that Cbl deficiency results in an increase in the MCM protein level in COS-7 cells as well as in rat liver.
A series of experiments on the surface reactions of hydrogen and deuterium atoms with solid CO, formaldehyde (H2CO), and methanol (CH3OH) has been performed. Successive hydrogenation of CO on surfaces at $\sim $10 K was found to proceed efficiently via tunneling to produce H2CO and CH3OH on dust grains under the typical conditions of molecular clouds. Formation rates are strongly dependent on the surface temperature and composition. The role of surface reactions in the formation of deuterated formaldehyde and methanol was investigated. The deuterium fractionation of methanol observed in molecular clouds was reproduced experimentally via H-D substitution in solid methanol at an accreting atomic D/H ratio of 0.05-0.1. This is the first evidence that grain-surface reactions can be responsible for fractionation. We have determined several effective rate constants for hydrogenation, deuteration, and H-D substitution to construct the surface reaction network for CO, H2CO, CH3OH, deuterated formaldehyde, and deuterated methanol.
It is estimated that in the year 2020, approximately 25% of the Japanese population will be over 65 years of age. Moreover, suicide is a significant public health problem in Japan, where more than 6,000 elders take their lives each year. The authors compare late-life suicide in urban Kawasaki with suicide among the elderly in rural Higashikubiki over a 12-year period, from 1979 through 1990. The suicide rates in Kawasaki were lower than for Japanese elders as a whole, whereas those in rural Higashikubiki were extraordinarily high. The most frequent method used in both areas was hanging, and none of the victims died of gunshot wounds. In Higashikubiki, almost two thirds of victims lived in a three-generation family and none lived alone. The change of the family system from the traditional extended family to the nuclear family is accelerating, especially in rural areas. The authors suggest that the greatly elevated suicide rates among the elderly in Higashikubiki, and in rural regions of Japan more generally, result from these rapidly occurring changes in traditional social structure.
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