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Continuous exposure of cells to exogenous and endogenous agents produces many types of DNA damage during normal cell cycles. Post-replication repair, consisting of error-free and error-prone sub-pathways, is required for tolerance of such DNA damage. REV1 plays a crucial role in regulation of the error-prone pathway. To facilitate analysis of its cellular functions, we here generated a mouse REV1 monoclonal antibody, called D6, which also recognizes human REV1. The epitope for the antibody could be mapped between 860-877 amino acid residues of human REV1, which was located outside of the conserved catalytic domain. Although the antibody unfortunately could not specifically detect endogenous mouse and human REV1 by western blotting and immunohistochemistry, we established a method to identify endogenous human REV1 by immunoprecipitation-western blotting analysis combining D6 and separately generated polyclonal antibodies.

Physico-chemical properties in the brine and under-ice water were measured in Saroma-ko Lagoon on the northeastern coast of Hokkaido, Japan, which is connected to the Sea of Okhotsk, during the period from mid-February through mid-March 2006. The brine within brine channels of the sea ice was collected with a new sampling method examined in this study. Salinity, dissolved inorganic carbon (DIC), total alkalinity (TA), dissolved oxygen (DO), nutrients and oxygen isotopic ratio (δ18O) contained in the brine within brine channels of the sea ice and in the under-ice water varied largely in both time and space during the ice melt period, when discharge from Saromabetsu River located on the southeast of the lagoon increased markedly due to the onset of snow melting. The under-ice plume expands as far as 4.5 km from the river mouth at mid-March 2006, transporting chemical components supplied from the river into the lagoon. The under-ice river water was likely transported into the sea ice through well-developed brine channels in the sea ice due to upward flushing of water through brine channels occurred by loading of snowfalls deposited over the sea ice. These results suggest that the river water plume plays an important role in supplying chemical components into the sea ice, which may be a key process influencing the biogeochemical cycle in the seasonally ice-covered Saroma-ko Lagoon.

Measurements of ice thickness were carried out by a ship-borne electromagnetic induction instrument mounted on the R/V Xuelong during the Second Chinese National Arctic Research Expedition (CHINARE-2003) in summer 2003 in the Chukchi Sea. A 1-D multi-layer model, consisting of three layers of snow, ice and seawater, was used to calculate the total thickness of snow and sea ice. The time series of total thickness from 24 August to 7 September 2003 indicates that deformed and second-/multi-year ice floes appear frequently in very close pack ice farther from the ice edge, while thinner ice floes less than 1 m are frequently found in open pack ice. The probability density function of total thickness shows that a major peak appears at around 1.5 m thickness in very close pack ice, presumably corresponding to second-year or deformed ice. Also shown is a peak at around 0.3 m thickness, corresponding to typical level ice in open pack ice.

The 18th IAHR International Symposium on Ice. 28 August - 1 September 2006. Sapporo, Japan., Ice in natural waters grows and decays as forced by the fluxes through the upper and lower boundaries. In particular, the flux at the lower boundary -- i.e. the heat flux from the liquid water body into the bottom of the ice sheet -- is not very well known quantity. This question is approached by measurements and mathematical modelling. The data are from Saroma-ko lagoon, a saline lake on the northern coast of Hokkaido, and Lake Pääjärvi, a fresh water basin in southern Finland. Three-dimensional current velocity, temperature and salinity were measured at a fixed depth, and the resulting heat flux was normally 5-10 W/m2 in both basins, a bit more in Saroma. But even in Lake Pääjävi, which is a rather quiet water body in wintertime (total ice coverage with very weak currents) the heat flux from the water is important in the heat budget of the ice sheet. A three-layer (snow/snow-ice/congelation ice) model is used to examine the evolution of ice thickness and temperature.

In order to understand the transition in sea ice, snow transformation, and temperature variations, we carried out tank experiments in a cold room. In the melting experiment of bare ice, the transition of the condition of the ice surface was observed through visual observations and reflectance measurements. The first change was manifested in the surface becoming wet and acquiring a rough texture. Subsequently, a porous layer was formed under the ice surface. Since this layer scattered the incident light, it appeared as a bright surface. The reflectance of this surface was high as compared with that measured during the initial stages of melting. However, this thin scattering layer disappeared as the melting progressed. As a result, the reflectance was reduced to its value during the initial stage of melting. In the melting experiments on snow covered sea ice, the structure of snow-ice become porous and mechanically weak before the thickness reduction commenced. The temperature gradients of bare ice and snow covers ice were small during the melting process compared to those during the growth period., application/pdf

In 1987 an ice core to bedrock at a depth of 85.61m was recovered at Hoghetta ice dome in northern Spitsbergen. The ice temperature measured in the borehole was －11℃ at 10m depth and －9.4℃ at the bottom. Sudden transitions from large grains to small ones were observed in vertical thin sections of grains near the surface. These boundaries seem to indicate the discontinuity of the ice formation process which occurs periodically every year. Therefore, the boundaries can be used for identifying annual layers. From structural analyses of the ice cores at different 10 depths, it was found that grains of ice were inter-locked and have irregular boundary shapes in the middle depths. Some of them showed an elongated shape, the orientations of which seem to be perpendicular to the girdle plane derived from ice fabrics. These interlocking and elongated grains, along with characteristics of ice fabrics, can be related to a past specific stress condition in the ice body. We can speculate that the ice of the middle depth (approximately 20m - 65m) is remnant ice from a larger ice cap than at present, spread over northern Spitsbergen after the hypsithermal period., application/pdf

Article, 講演番号：4 E5 38 日本化学会第78春季年会, 平成12年3月28日～3月31日, 船橋

Air bubbles were observed in an ice core form Asgardfonna, Spitsbergen. These were classified into four types by their shape and distribution pattern (uniform distribution type, bubble layer type, cylindrical type and cobwebbed type). Also parts which contained few air bubbles (clear type) were observed in the ice core. On the basis of this classification, distribution of each pattern of air bubbles was investigated through the entire ice core (85.5m). Inhomogeneous distribution of each pattern with depth was observed, and was probably a result of differences of formation process or of stress condition in the ice body. From the observation of air bubbles and grains, it was found that clear parts which contain few air bubbles are composed of grains 2 to 4 times larger than those of the neighboring parts, and that “cobwebbed air bubble type” was observed only at grain boundaries. If this type of air bubbles was affected by solar radiation during the formation process, they probably reflect that a bare ice field existed at that time., application/pdf

Glaciological investigation was carried out on Jostedalsbreen (61゜43′N､7゜08′E), Southern Norway, in early May, 1987, as a study of the Japanese Arctic Glaciological Expedition (JAGE 1987) which intended to define the glaciological characteristic in the maritime cryosphere. The 46.9 m full depth ice core was recovered at a dome of the glacier (1960 m a.s.l.). Then glaciological and geochemical in situ analyses of the cores were made to made to clarify the past climatic change. The cooperative study was with institutions of Norway. Several dirt layers were found in the cores ; the dirt layers in the upper part indicate the corresponding maximum values of electrical conductivity, different from layers in the lower part. Infiltrating water of about 1 m thick appeared in the borehole, showing a confined aquifer on the bedrock. The temperature of the borehole was nearly 0℃ through the entire depth except at the upper part and the firn transformed abruptly into ice at 29.5 m; these results implied that the whole glacier has the property of a temperate glacier. The grain size increased one order of magnitude in a short interval just below the firn-ice interface, probably due to immersion of ice body into 0℃ water. A significantly large dip of foliation at the middle layer suggested existence of glacier flow at the boring site. The annual layers were not identified from seasonal variations of in situ analyses. However, from accumulation data for the last 20 years, the age bottom ice was estimated to be about 17 years before the present investigation., application/pdf

To make a pilot-hole for deep core drilling at Dome Fuji Station, East Queen Maud Land, Antarctica, shallow ice core drilling was conducted to a depth of 112.59 m by electro-mechanical drill. Core logging, measurements of impermeability and bulk density were conducted in situ and most of another analysis was done in Japan．Much depth hoar developed at Dome Fuji Station. However, it did not influence the densification rate, which mainly depends on temperature. Air bubble close-off starts from about 90 m depth. Much accumulation at one time occurs during marine cyclones at Dome Fuji Station., application/pdf

Analyses of SO^_4, Na^+，Cl^-，Mg^ and Ca^in ice core samples of multiyear sea ice in the Fram Strait show strong correlations between the concentrations of Mg^，Na^+，Cl^- and Ca^（r=0・99）while the correlation coefficients between these ions and SO^_4 were less than O．9．Most samples had a deficit of sulfate relative to sea water of the same salinity. Excess sulfate was found in a few samples with low salinities．Chemical analyses of snow，ice and meltwater from temperate glaciers have demonstrated that sulfate is more efficiently washed out when meltwater penetrates through ice than are Cl^?，Mg^ and Ca^．Washout therefore leads to deficit of sulfate in ice，whereas refreezing of meltwater creates an excess of sulfate relative to sea water with the same content of chloride．, application/pdf