Massive ground ice found in the Barrow Permafrost Tunnel at 3–7 m depths from the surface has been interpreted as an ice wedge and used to reconstruct early Holocene environmental changes. To better understand the development of this ground ice, we conducted radiocarbon dating for 34 samples of plant remains from the massive ground ice and underlying sediment layer. A significantly large gap in the measured radiocarbon ages (more than 24 ka) between massive ice and the underlying sediment layer throughout the tunnel profile suggested at least two possibilities. One is that the lower and older sediment layer had thrust upwards at the boundary between intruding ice wedge and adjacent sediment, and the growing ice had pushed the sediment sideways. Another is that erosional events had removed surface materials at about 12–36 ka BP (14–41 cal ka BP) before the overlaying sediment layer with massive ground ice developed. The overall distribution of radiocarbon ages from the massive ice supported the ice-wedge hypothesis as a formation mechanism, although our results showed several age inversions and large fluctuations. Dating of densely spaced samples revealed two ground-ice regions with similar ages around 11–11.5 and 10–10.5 ka BP divided by a relatively narrow region of transitional ages along the tunnel long-axis. This distribution may be explained by a possible misalignment between the sampling direction and the ice-wedge growth line or by intermittent ice growth with repeated cracking at more random locations than the classic ice-wedge growth model suggested.

Earlier gas measurements of firn air (atmosphere in open pore channels) at polar sites have revealed the occurrence of gas fractionation phenomena during bubble close-off, in addition to well-known thermal and gravitational gas separation. Nevertheless, because of difficulties posed by measurement, little is known about the distribution of air constituents in already closed pores (bubbles) in firn. Herein, we describe the application of high-sensitivity pure rotational Raman spectroscopy, combined with sample immersion in the fluorocarbon-based inert fluid for removing the optical disturbance by diffused reflection. That application efficiently elicits information about nitrogen and oxygen composition ratios (N2/O2 or O2/N2) for each air bubble in firn. The developed methodology presents important implications for elucidating how gas records are formed and modified in the course of pore close-off in polar firn.

Maternal gut microbiota is thought to be one of the important factors in the developmental origins of health and disease (DOHaD) concept, but the effects of maternal gut microbiota on foetal growth are not well known. In this study, the association between maternal gut microbiota and foetal growth was investigated. Maternal and newborn information, as well as stool samples at the third trimester of pregnancy, were obtained from 51 mother–newborn pairs from the Chiba study of Mother and Child Health (C-MACH). Gut microbiota was analysed by 16S rRNA sequencing of stool samples and short-chain fatty acids (SCFAs) in stool were analysed by gas chromatography-tandem mass spectrometry. After adjustment for covariates, it was found that maternal gut microbial diversity had a positive association with head circumference in newborn males (Chao 1: adjusted r = 0.515, p = 0.029). Genus Parabacteroides and genus Eggerthella showed negative associations with newborn head circumference and weight, respectively in males (genus Parabacteroides: adjusted r = −0.598, p = 0.009, genus Eggerthella: adjusted r = −0.481, p = 0.043). On the other hand, genus Streptococcus showed a negative association with newborn height in females (adjusted r = −0.413, p = 0.040). In addition, hexanoate was involved in the association between maternal gut microbiota and newborn anthropometrics in the univariate analysis, but not in the multivariate analysis. These data suggest that maternal gut microbiota has sex-specific effects on foetal growth. Maternal gut microbiota is an important factor for optimal intrauterine growth.

To investigate factors influencing nucleation of air clathrate hydrates in polar ice sheets, we have performed high-resolution mapping of the distributions of soluble impurities, air bubbles and air- hydrate crystals versus depth in the Dome Fuji Antarctic ice. Significant correlation observed between the concentrations of air inclusions and impurities in ice along with frequent occurrence of impurities inside hydrate crystals suggest that micro-inclusions promote hydrate nucleation in the ice matrix. Our observations also show that the diffusive macroscopic-scale redistribution of air constituents in ice in the bubble-hydrate transition zone is controlled by the original sedimentary layering of soluble impurities acting as nucleation helpers. The results of this study are important for the correct interpretation of high-resolution gas analyses of ice cores and for better understanding the global bubble-to-hydrate transformation process in polar ice sheets.

Using micro-Raman spectroscopy, we identified the chemical forms of methanesulfonate salt particles in reference samples of the Dome Fuji (Antarctica) ice core. We found only (CH3SO3)2Mg nH2O among methanesulfonate salts, and this salt particle is most prevalent in the Last Glacial Maximum (LGM) ice. We suggest that during the LGM, (CH3SO3)2Mg nH2O may have formed in the atmosphere through the chemical reaction of CH3SO3H with sea salts, but probably not in the firn and ice due to the neutralization of acid in LGM ice of inland Antarctica.

This study clarifies changes in the chemical forms of microparticles during Termination I, the period of drastic climate change between the Last Glacial Maximum (LGM) and the Holocene. We determine the chemical forms of individual water-soluble microparticles through micro-Raman spectroscopy and compare the relative frequencies of different types with the ion concentrations in melted ice. Micro-Raman spectroscopy shows that Na2SO4·10H2O and MgSO4·11H2O are abundant in Holocene ice, while CaSO4·2H2O and other salts are abundant in LGM ice. Further, the number of CaSO4·2H2O particles is strongly correlated with the concentration of Ca2+ during Termination I. Taken together, the evidence strongly suggests that most of the Ca2+ exists as CaSO4·2H2O. The different compositions of microparticles from the Holocene and LGM can be explained by ion balance arguments.

Recently, the ability of polyphenols to reduce the risk of dementia and Alzheimer's disease (AD) has attracted a great deal of interest. In the present study, we investigated the attenuating effects of oligomerised lychee fruit-derived polyphenol (OLFP, also called Oligonol) on early cognitive impairment. Male senescence-accelerated mouse prone 8 (SAMP8) mice (4 months old) were given OLFP (100 mg/kg per d) for 2 months, and then conditioned fear memory testing was conducted. Contextual fear memory, which is considered hippocampus-dependent memory, was significantly impaired in SAMP8 mice compared with non-senescence-accelerated mice. OLFP attenuated cognitive impairment in SAMP8 mice. Moreover, the results of real-time PCR analysis that followed DNA array analysis in the hippocampus revealed that, compared with SAMP8 mice, the mRNA expression of Wolfram syndrome 1 (Wfs1) was significantly higher in SAMP8 mice administered with OLFP. Wfs1 reportedly helps to protect against endoplasmic reticulum (ER) stress, which is thought to be one of the causes for AD. The expression of Wfs1 was significantly up-regulated in NG108-15 neuronal cells by the treatment with OLFP, and the up-regulation was inhibited by the treatment of the cells with a c-Jun N-terminal kinase-specific inhibitor rather than with an extracellular signal-regulated kinase inhibitor. Moreover, OLFP significantly attenuated the tunicamycin-induced expression of the ER stress marker BiP (immunoglobulin heavy chain-binding protein) in the cells. These results suggest that OLFP has an attenuating effect on early cognitive impairment in SAMP8 mice, and diminishes ER stress in neuronal cells.

The Er that is rare earth element causes luminescence at 1540 nm, which is a low loss transmission window in silica-based fibers used in optical communications. Moreover, it is known that the temperature quenching of the luminescence of Er becomes smaller with the wide band gap of the host material. We report on the photoluminescence (PL) characteristic and X-ray diffraction (XRD) of AlN:Er thin films which are deposited by RF reactive magnetron co-sputtering method. All the thin films were deposited by RF reactive magnetron co-sputtering method from a 99.999 % Al target and 99.99 % Er chips in a nitrogen gas (99.9998 %) atmosphere. The thin films were achieved with a discharge power of 250 W in a total pressure of 5.0∼10-3 Torr, and the deposition times were one hour. After the deposited, these samples were annealed for 30 minutes in the temperature range from 400 to 900° in a nitrogen gas (99.999 %) atmosphere with an infrared lamp heater. PL spectra of AlN:Er were measured using the 325 nm line of a He-Cd laser at 15 K. Consequently, we observed PL spectra around 1500 nm. The strong luminescence of peak wavelength at 1538 nm is based on the intra-4f emitting centers of Er. We report systematically the experimental results of PL and XRD.

Accurate measurement of the lattice misfit between the γ and γ phases in Ni-base single crystal superalloys at high temperatures has successfully been achieved using a parallel beam mode X-ray diffractometer with a high temperature specimen stage. The superalloys have γ' precipitates, an ordered FCC structure based on Ni3Al, in a γ-matrix having a disordered FCC structure (LI2). The parallel beam mode, the optics of which is made from a Ge (111) channel cut crystal, generates a superior monochromatic and parallel CuKα1 beam, which makes it possible to resolve a cluster peak in Ni-base superalloys into individual γ and γ ‘ peaks. This peak separation was almost impossible using the CuKα1+2 doublet beam from the standard type para-focusing mode, due to the very small difference in lattice parameters between the two phases.

The charge collection efficiency of a diode with a retrograde well was estimated using focused ion beam irradiation at 400 keV and 2 MeV. The retrograde well was found to effectively suppress a collection of charge carriers created by energetic particles. The charge collection efficiency of the diode with the retrograde well was ~ 25 % lower than that with the conventional well when 400 keV ~ 2 MeV protons were irradiated normal to diodes. This result was in good agreement with device simulation.

A method for using syncrotoron-radiation parallel-beam X-ray diffractometry for precise lattice parameters and strains of γ-γ′ type Nickel base superalloys at elevated temperature is described. The superalloys have γ′ precipitates which are an ordered L12 structure based on Ni3Al, in y-matrices having a disordered FCC structure. Lattice misfit between γ and γ′ phases was very small and peaks reflected from γ and γ′ phases made unresolved clusters of peaks.

Profile fitting with a pseudo-Voigt function is used to resolve overlapping peaks. Instrumental broadening of the peak profile was removed using a deconvolution method. The standard errors of the calculated peak angle were less than 0.002°. The elastic strain of the γ′ precipitates in the alloys were smaller than those of γ-matrices.

In order to control reactive silane(SiH4) glow discharge plasmas for an a-Si:H thin film synthesis, we have investigated the dependence of plasma parameters on the crossed magnetic field B perpendicular to the discharge electric field E. As the result of modification of plasma structure by a crossed magnetic field, subsequent modified profiles of optical emission from SiH radicals were observed. On the other hand, Hα, emission in the cathode sheath region, which may be caused by high energy secondary electrons(γ-electron), were not so much influenced by a magnetic field. By modulating the crossed magnetic field in AC discharge plasmas, the time-averaged uniform (2.5% inhomogeneity) profile of SiH radical could be realized near the substrate sustained outside the discharge region.

The lattice parameters and strain of ϒ'-phase particles in Nickel-base superalloys, which are duplex type alloys designed for turbine blades and widely called “Ni-base single crystal superalloys”; they are accurately determined by Synchrotron Radiation parallel-beam diffractometry. The superalloys have ϒ' precipitates, an ordered FCC structure based on Ni3Al, in a γ-matrix having disordered FCC structure.

In addition, the preparation method of stress-free ϒ'-phase particles, with no composition change in the preparation process, was newly developed to measure the coherency strain of ϒ'-particles due to lattice misfit. The prepared ϒ'-phase particles are similar in composition and form to ϒ'-phase particles in the γ-matrices. The method for determining of the lattice misfit between the γ and γ’ particles was previously reported.

A numerical resolution-enhancement method was developed for x-ray diffraction data measured with a conventional x-ray diffractometer. This method removes the instrumental broadening due to x-ray optics, including the spectral distribution of the x-ray source such as the CuKα doublet. The advantages of this method are to separate the cluster of peaks in x-ray powder patterns into individual peaks without previous knowledge of the number of peaks, and to remove CuKα2 reflection peaks automatically.

The instrumental window function, which was approximated by a modified pseudo-Voigt function, was calculated from the measured diffraction pattern of NBS Standard Reference Materials (640B) by a non-linear least squares method. The simple diffraction patterns, including no CuKα2 peaks, were obtained from the diffraction patterns measured with the conventional x-ray diffractometer by using the window function mentioned above.

The application of the method of determination of the lattice misfit between γ and γ phases in Ni-base superalloys was also described.