Observation of Allende and Antarctic meteorites by monochromatic X-ray CT based on synchrotron radiation

Three-dimensional CT images of the Allende meteorite with a high resolution of 10μm have been obtained nondestructively by a monochromatic X-ray computed tomography (CT) based on synchrotron radiation (SR). The metallic minerals, matrix and chondrules can be clearly observed in the CT images. The CT values, which express the image intensity, allow a quantitative elemental analysis including such as difference in the metallic minerals, i. e., pentlandite and troilite, using the comparison of CT images and elemental images measured by a computer-aided microanalyzer (CMA). The three-dimensional CT images indicate that the metallic minerals surround some chondrules, and the largest chondrule has two humps and well crystallized olivine in its center. These observations suggest that the three-dimensional SR-CT system is a useful method for identification of internal structures of stony meteorites. Additionally, information obtained from the CT images of Antarctic meteorites confirms that the SR-CT system can be applied to classification of stony chondrites

Differential gene expression profiling in blood from patients with digestive system cancers

金沢大学医薬保健研究域医学系To develop a non-invasive and sensitive diagnostic test for cancer using peripheral blood, we evaluated gene expression profiling of blood obtained from patients with cancer of the digestive system and normal subjects. The expression profiles of blood-derived total RNA obtained from 39 cancer patients (11 colon cancer, 14 gastric cancer, and 14 pancreatic cancer) was clearly different from those obtained from 15 normal subjects. By comparing the gene expression profiles of cancer patients and normal subjects, 25 cancer-differentiating genes (p3) were identified and an " expression index" deduced from the expression values of these genes differentiated the validation cohort (11 colon cancer, 8 gastric cancer, 18 pancreatic cancer, and 15 normal subjects) into cancer patients and normal subjects with 100% (37/37) and 87% (13/15) accuracy, respectively. Although, the expression profiles were not clearly different between the cancer patients, some characteristic genes were identified according to the stage and species of the cancer. Interestingly, many immune-related genes such as antigen presenting, cell cycle accelerating, and apoptosis- and stress-inducing genes were up-regulated in cancer patients, reflecting the active turnover of immune regulatory cells in cancer patients. These results showed the potential relevance of peripheral blood gene expression profiling for the development of new diagnostic examination tools for cancer patients. © 2010 Elsevier Inc

Preparation of Si-carbon nanotube composite by decomposition of tetramethylsilane (TMS) and its hydrogen storage property

Hydrogen storage property of Si-carbon nanotube composite was studied. It was found that the carbon nanotube coated Si particle was prepared by the decomposition of tetramethylsilane by using Ni catalyst. The obtained composite was consisted of the spherical Si particle with 300 nm diameter and the surface of Si particle was coated with carbon nanotube with 10 nm diameter. The obtained Si-carbon nanotube composite shows a fairly large hydrogen storage capacity of 2.5 wt%. The amount of storage H2 increased with increasing the preparation temperature and the largest hydrogen storage amount could be achieved at 1273 K for 6 h. Fairly large hydrogen storage capacity could be sustained after 3 cycles of adsorption and desorption

Theoretical Solution Energy of Alkaline Earth Ions in Lanthanum Chromites

First principles calculations by a plane-wave basis pseudopotential method have been made for Mg, Ca, and Sr-doped lanthanum chromites (LaCrO 3 ). A supercell composed of 40 atoms of a high temperature phase of LaCrO 3 having a cubic-perovskite structure has been used. Solution energies of a neutral solute and a compensated solute by an oxygen vacancy were systematically computed. They were obtained for two kinds of cation sites and four thermodynamical conditions with different chemical potentials of constituent atoms. Mg shows lowest solution energy when it substitutes for the Cr ion. On the other hand, both Ca and Sr prefer to be located at La site. The charge neutral states are preferred by all of them. The results are consistent to experimental results regarding the site preference and the charge state

Regulation of radiation-induced protein kinase Cdelta activation in radiation-induced apoptosis differs between radiosensitive and radioresistant mouse thymic lymphoma cell lines

Protein kinase Cd(PKCd) has an important role in radiation-induced apoptosis. The expression and function of PKCd in radiation-induced apoptosis were assessed in a radiation-sensitive mouse thymic lymphoma cell line, 3SBH5, and its radioresistant variant, XR223. Rottlerin, a PKCd-specific inhibitor, completely abolished radiation-induced apoptosis in 3SBH5. Radiation-induced PKCd activation correlated with the degradation of PKCd, indicating that PKCd activation through degradation is involved in radiation-induced apoptosis in radiosensitive 3SBH5. In radioresistant XR223, radiation-induced PKCd activation was lower than that in radiosensitive 3SBH5. Cytosol PKCd levels in 3SBH5 decreased markedly after irradiation, while those in XR223 did not. There was no apparent change after irradiation in the membrane fractions of either cell type. In addition, basal cytosol PKCd levels in XR223 were higher than those in 3SBH5. These results suggest that the radioresistance in XR223 to radiation-induced apoptosis is due to a difference in the regulation of radiation-induced PKCd activation compared to that of 3SBH5. On the other hand, Atm-/- mouse thymic lymphoma cells were more radioresistant to radiation-induced apoptosis than wild-type mouse thymic lymphoma cells. Irradiated wild-type cells, but not Atm-/- cells, had decreased PKCd levels, indicating that the Atm protein is involved in radiation-induced apoptosis through the induction of PKCd degradation. The decreased Atm protein levels induced by treatment with Atm small interference RNA had no effect on radiation-induced apoptosis in 3SBH5 cells. These results suggest that the regulation of radiation-induced PKCd activation, which is distinct from the Atm-mediated cascade, determines radiation sensitivity in radiosensitive 3SBH5 cells