A comprehensive study of ice-crystal fabrics and textures was conducted on the Dome F (Antarctica) ice core. Crystal ,-axis orientations, crystal sizes and crystal shape were measured on thin sections with an automatic ice-fabric analyzer. The general feature of textural and fabric development through a 2500 m long core was obtained by a 20 m interval study. Crystal size steadily increases with depth except for depths of about 500,1800, 2000, 2200 and 2300 m, at which depths crystal size decreases suddenly. There is a clear correlation between crystal-size and ´18O values. Crystals tend to elongate horizontally with depth, and the aspect ratio (long axis vs short axis of a grain) increases twofold at 1600 m depth and fluctuates below that depth. The .-axis orientation fabrics gradually change with depth from a random orientation pattern near the surface to a strong vertical single maximum at 2500 m. These are very similar to those from the GRIP (Greenland) core The observations of crystal shape and the fabric measurements indicate that nucleation-recrystallization does not take place at Dome F.

An X-ray transmission method has been developed to obtain a continuous profile of bulk densities of ice cores. Intensities of X-rays transmitted through an ice-core sample were continuously measured by an X-ray detector during translation of the sample across the X-ray beam. A thick section of an ice core with a constant thickness was prepared by band-sawing followed by microtome planing. The X-ray intensity profile obtained was converted to a density profile using a calibration curve for X-ray absorption vs ice thickness. Using this method, spatial resolution of the density profile was down to 1 mm. X-ray radiographs were also taken on a two-dimensional detector imaging plate, in order to observe layer structures of the ice cores.

The method was applied to Dome Fuji (Antarctica) ice cores from the surface to 110 m depth. From the density profile obtained we calculated the power spectrum of the density variation by the discrete Fourier transform, and obtained several peaks at different frequencies. The center period in the spectrum was close to the annual accumulation thickness at the drill site.

A deformation mechanism map for pure polycrystalline ice of 2 mm grain diameter is constructed, New sub-regions in the dislocation glide region are proposed: dislocation glide with crack formation, dislocation creep, and fracture at high stresses above about 1 MPa. The boundary between the dislocation creep and DGC regions is determined by the onset of cleavage cracks due to piled-up dislocations near grain boundaries. The fracture region is that area of the map where fracture occurs readily when the ice is subjected to a rapid deformation rate exceeding 10-3 s-1. Experimental results of the stress dependence of the compressive deformation rate of polycrystalline ice are compared with the map. The effect of changes in the creep activation energy near the melting point is discussed together with those of other factors.

Tensile tests were carried out with core-ice samples obtained from various depths at Byrd Station, Antarctica in 1968, Specimens for the tests were so prepared as to have their long axes parallel (L specimen), perpendicular (T specimen), and inclined at 450 (I specimen) with respect to the axis of the core, or to the vertical direction of the ice sheet. Stress-strain relations for many specimens were obtained from tensile tests with different strain-rates and also at different temperatures between —10 and — 20°C.

We performed microscopic observations and a statistical study of the number, size and shape distribution of clathrates in the GRIP (Greenland Ice Core Project) deep ice core, using 185 samples from a depth range of 1016–3014 m, spanning a period of 6 to >110 ka BP and encompassing the Holocene, Wisconsin and Eemian periods. The number concentration of the clathrates varied considerably with climatic changes. It was possible to detect the rapid climatic oscillations in the last glacial between 13 and 110 ka BP, the Dansgaard–Oeschger cycles, in the number-concentration profile of clathrates. The mean volume of clathrates is less clearly influenced by climatic factors, with a tendency towards greater volumes in warmer periods, but also a growth of clathrates with depth could be detected. This growth rate was calculated to be 3.1 × 10-12 cm3 a-1. The amount of gases captured in the clathrates is estimated to be significantly smaller than the total amount of air determined by gas-concentration measurements. This points to diffusion processes of atmospheric gases within the ice matrix.

Crystal size and c-axis orientation patterns were measured on the Dye 3, Greenland, deep ice core in order to investigate time-dependent changes or alterations in the physical character of the core as a function of time after recovery. The physical measurements were expanded to include depth intervals not previously studied in the field. The recent study focused on core samples located between 1786 m and the bottom of the ice sheet at 2037 m.

Manual c-axis measurements were made on 23 new thin sections using a Rigsby-type universal stage. A new semi-automatic ultrasonic wave-velocity measuring device was developed in order to compare the results with the earlier manual measurements and to study an additional 114 ice-core samples in the Wisconsin-age ice. Crystal-size measurements were made on specimen surfaces by inducing evaporation grooves at crystal boundaries and measuring linear intercepts. The ultrasonically measured test samples were subsequently cleaned and analyzed by ion chromatography in order to measure impurity concentration levels of Cl−, NO3− and SO42− and study their effects on crystal growth and c-axis orientation.

Uniaxial compression tests (UCT) under constant cross-head speed and simple shear tests (SST) under constant load have been carried out in a snow cave at -16°C on ice cores within at most one month of extraction from depths of 235, 504, 708, and 896 m at Dye-3, Greenland, as part of the Greenland Ice Sheet Program (GISP), in order to improve understanding of flow behavior. UCT specimens had their stress axis at 45° from the core axis and SST specimens had their shear parallel to the horizontal plane of the core, so that in both cases maximum resolved shear stress was in the horizontal plane of the ice sheet.

Fracture stresses in UCT had characteristic values for each depth corresponding to core quality. When effective strain-rate was plotted against effective shear stress on a double logarithmic plot, (1) data from the same depth fell on the same straight line for both tests, (2) for a given stress, strainrate varied with core-depth by less than half an order of magnitude, and (3) the stress exponent lay between 2 and 2.5, significantly less than the 3 to 4 reported for polycrystalline ice.

Values extrapolated from the present data agree quite well with those deduced from bore-hole tilting measurements at Byrd station, Antarctica, and Camp Century, Greenland.

Horizontal and vertical distributions of melt features (ice layers) were examined using two ice cores (206.6 and 101.5 m deep, 1 m apart) from Site J (66°51.9′ N, 46°15.9′W, 2030 m a.s.l.). The temperature at 10 m was −16.3°C. We observed 2804 melt features, with a total thickness of 30.32 m, in the 206.6 m core, corresponding to 16.4% by volume of the ice-equivalent core length. Horizontal distribution of melt features was examined by correlating melt-feature thicknesses in the two cores. The correlation coefficient was 0.71 (n = 514) for each melt feature in the two cores. It was maximum for data passed through 5 and 40 year low-pass filters. A significant relationship (P = 0.005, n = 36) was obtained for the vertical distribution of melt features and the June temperature on the west coast of Greenland (Jakobshavn). Using this, June temperatures at Jakobshavn since 1550 were estimated. There are three periods (1685-1705, 1835-70 and 1933-45) during which mean June temperatures clearly decreased, when they were estimated to he 0.1°, 0.4° and 0.2°C lower than the average for the whole period (1550-1989). The first two “cold” periods have been identified in melt features of the Dye 3 and Devon Island ice cores and in a tree-ring profile from Yukon Territory, Canada. Melt-feature percentages in the Site J ice core have increased since about 1945, probably reflecting summer-temperature warming on the ice sheet.

Uniaxial compression tests under constant crosshead speed were carried out on 22 new specimens from the 268, 1890, 1944 and 2006 m depths of the Dye 3, Greenland, ice core. The measurements were made in a laboratory cold-room, using an Instron model 1131 apparatus. Test temperatures were held constant between −17° and −13° C, the approximate sample in-situ temperature. Specimens were prepared with various test orientations in relation to the long vertical core axis. The specimens were analyzed in terms of the content of dust, Cl−, NO3− and SO42− concentrations and various other physical parameters, such as ultrasonic wave velocities, c-axis orientation patterns and grain-size. The results of the previous uniaxial compression tests show that most of the flow occurs in the Wisconsin-age ice between 1786 m and the bottom of the ice sheet. This entire depth interval is strongly anisotropic, with a vertical c-axis fabric pattern. The enhancement factor, E, which was calculated from these tests ranges from 0.03 to 17. The Wisconsin-age ice is about ten times softer (Es = 10) than artificially made laboratory ice (E = 1). The combined results of the multi-parameter correlation analyses show that E is controlled primarily by the orientation strength of c-axes and that the impurity concentration-level variations contribute to a lesser degree.

The horizontal velocity of a thick ice sheet is maximum at the surface and decreases with increasing depth. The horizontal velocity profile at a given location differs from another location depending upon the in situ stress and temperature conditions and the changing but distinctive physical and chemical character of the ice profile. The main property changes that influence the behavior of horizontal ice flow include chemical impurity concentration levels (both solid and dissolved components) and c-axis orientation. Shoji and Langway (1984) calculated the velocity profiles for both the Camp Century and Dye-3 Greeland location by taking into consideration possible enhancement factor variations over the profiles. This analysis was compared with the theoretical and experimental strain rate data obtained for laboratory ice at the same stress and temperature levels. This study indicated that the largest horizontal velocity component is the result of a highly enhanced shear deformation zone, a few hundred meters thick existing at the base of the ice sheet.

Several studies have reported association of altered levels of lipids and some trace elements with risk factors for cardiovascular disease development in adulthood. Accordingly, the present study aimed to determine the relationship among the serum levels of copper (Cu), zinc (Zn), lipids, lipoproteins and apolipoproteins in preterm infants through an assessment of atherogenic indices shortly after birth. Blood samples were collected within 20 min of birth from 45 preterm infants with gestational ages ranging from 32 to 35 weeks. Serum Cu, Zn, total cholesterol (TC), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc), apolipoprotein-A1 (apoA1) and apolipoprotein-B (apoB) levels were measured, and the TC/HDLc, LDLc/HDLc and apoB/apoA1 ratios were calculated. Upon determining the correlation between the levels of Cu, Zn and these indices of lipid metabolism, triglyceride (TG) and Cu were found to correlate negatively with birth weight (BW) and the standard deviation (s.d.) score for body weight. Furthermore, Cu levels correlated positively with the TG level and TC/HDLc, LDLc/HDLc and apoB/apoA1 ratios and negatively with the HDLc level and HDLc/apoA1 ratios. However, a stepwise multiple regression analysis indicated that the s.d. score for BW and TG level were significant independent determinants of the Cu level. In contrast, Zn did not correlate with any of these indices. In conclusion, intrauterine growth restriction and the TG level at birth influence Cu levels in preterm infants, whereas atherogenic indices do not affect this parameter.

Femtosecond laser direct writing (FsLDW) in transparent materials is a laser-based precise three-dimensional (3D) micro/nanofabrication method that has shown great potential for applications. The advantages of FsLDW originate in the nonlinear nature of absorption in the multiphoton absorption process. Over the past few years, transparent material micro/nanofabrication using FsLDW has seen several developments in materials and applications. Specifically, two-photon polymerization has been widely used as a precision direct-writing process for fabrication of polymeric 3D micro/nanostructures; internal/surface ablation of polymer 3D structures based on multiphoton absorption has been demonstrated and developed as a promising subtractive manufacturing technique; and femtosecond laser multiphoton modification in glass has been intensively studied for refractive-index change and generation of nanogratings and microvoids. This article describes the latest research on FsLDW in polymers and glasses with specific applications for large-dimension fabrication, microelectromechanical systems, microphotonics, and microfluidics.

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the incretin hormones secreted from the intestine in response to enteral feeding to stimulate insulin secretion. We investigated the relationship serum GIP and GLP-1 levels with gestational age, and insulin secretion in preterm infants. Serum GIP and GLP-1 levels were measured at birth and at 1, 2 and 4 weeks after birth in 30 infants, including 12 born before 30th week of gestation (early group) and 18 born after 30th week of gestation (late group). Blood glucose and serum insulin levels were measured, and the quantitative insulin sensitivity check index (QUICKI) was also calculated. The levels of GLP-1 at 2 and 4 weeks were significantly higher in the early group than those in the late group. The levels of GIP were not significantly different between two groups. At 4 weeks, serum insulin level was significantly higher and QUICKI was significantly lower in the early group. Furthermore, GLP-1 levels were significantly correlated with QUICKI and the serum insulin levels in all infants at 4 weeks. In preterm infants, enteral feeding to premature intestine may be associated with GLP-1 secretion. GLP-1 is also related to stimulated insulin secretion in early postnatal period.

Evidence suggests that breastfeeding during infancy lowers the risk of metabolic syndrome (MS) and its attendant risk factors in adult life. To investigate the influence of feeding type on the risk factors of MS, we assessed insulin sensitivity and lipid and apolipoprotein metabolism in preterm infants. Blood samples were collected from preterm infants at the time of discharge. Infants were separated into two groups: a breast milk (BM) group receiving ⩾90% of their intake from BM, and a mixed-fed (MF) group receiving ⩾50% of their intake from formula. The following indices were then compared between the two groups. Blood glucose and serum insulin levels were used to calculate the quantitative insulin sensitivity check index (QUICKI). We also measured serum total cholesterol (TC), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc), apolipoprotein-A1 (apoA1) and apolipoprotein-B (apoB) levels, and the ratios of TC/HDLc, LDLc/HDLc and apoB/apoA1. The mean gestational age was 32.9 weeks at birth, and blood samples were collected at a mean corrected age of 37.4 weeks. There were 22 infants in the BM group and 19 in the MF group. QUICKI was significantly higher in the BM group. TC, HDLc and apoA1 were not significantly different between the groups, but LDLc and apoB levels were significantly higher in the BM group. The TC/HDLc, LDLc/HDLc and apoB/apoA1 ratios were significantly higher in the BM group. In preterm infants, the type of feeding exposure in the early postnatal period may influence glucose, lipid and apolipoprotein metabolism, and affect markers of MS.

The relationship between varicella-zoster virus and idiopathic associated laryngeal paralysis was examined in five patients, using complement fixation or enzyme immunoassay testing. In all cases, significant changes in serum levels of varicella-zoster virus antibody were observed. Videofluoroscopy was useful in assessing the severity of the dysphagia and in making an accurate diagnosis; both laryngeal elevation and weakness of pharyngeal wall contraction were also observed. In two cases in which antiviral therapy was delayed, the outcome was poor, with increased levels of varicella-zoster virus immunoglobulin M found on enzyme immunoassay. The outcome of the condition may thus depend both on the speed of antiviral therapy commencement following onset of symptoms, and on the levels of varicella-zoster virus immunoglobulin M antibody (measured by enzyme immunoassay). Our study suggests that varicella-zoster virus should be considered in the differential diagnosis of patients with idiopathic associated laryngeal paralysis, and rapid antiviral therapy should be initiated when necessary.

We used Monte Carlo simulation code DEGAS and studied the neutral particle behavior in the Compact Helical System (CHS) three-dimensionally. In contrast to other helical devices, the CHS plasma in the standard configuration has contact with the inner vacuum vessel wall like the material limiter used in many Tokamaks and the neutral recycling becomes dominant there. As the intensity of neutral recycling changes also along toroidal direction, we extended our previous simulation model geometry three-dimensionally and compared the results of these models. We found the variation of the gap between the vacuum wall and main plasma enhanced toroidal transport of hydrogen molecules and atoms. As the formation of the edge transport barrier (EBT) discovered recently in CHS is characterized by a clear drop in Hα emissions, it is interesting to study the relationship with the profile of atomic/molecular hydrogen and the Hα emission profile. We estimated emission not only from excited hydrogen atoms but also from dissociated molecules with a collisional radiation model. We found that our Hα detector signal in CHS mostly came from excited atoms and that the emission profile largely changed with the ETB formation.

We have developed a Multi-component Zone Melting method to grow a ternary compound crystal which has a uniform composition. A 4.5 mm long InGaAs bulk crystal with a uniform InAs composition of 0.3 has been successfully grown using this method. InGaAlAs/InGaAs strained quantum well lasers were fabricated on an In0. 2Ga0.8As substrate which was grown by this method. A minimum threshold current density of 280 A/cm2 was achieved.