Chemical characteristics of a Martian meteorite, Yamato 980459

As a part of consortium study, we analyzed a Martian meteorite, Yamato (Y) 980459 by prompt gamma-ray analysis (PGA), instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). Our data confirmed that Y980459 belongs to olivine-phyric shergottites in chemical composition. Based on mg numbers (molar Mg(Mg+Fe) ratio), olivine-phyric shergottites are divided into two subgroups with high mg number and low mg number. Y980459 is grouped into members with high mg number along with DaG 476 and SaU 005. Abundances of rare earth elements (REEs) in Y980459 are depleted in light REEs (LREEs) and are similar to those of DaG 476 and SaU 005, being different from those for EETA 79001A, Dho 019 and NWA 1068, which are less depleted in LREEs. Based on the REE abundance in Y980459, a value of 0.19-0.25 was derived for the fraction of Martian crust in the Shergotty meteorite

Chemical composition of Yamato (Y) 000593 and Yamato 000749: Neutron-induced prompt gamma-ray analysis study

Neutron-induced prompt gamma-ray analysis (PGA) was applied to Antarctic nakhlites, Yamato (Y) 000593 and Y000749 together with Nakhla for the non-destructive determination of most major and minor elements (plus some trace elements). In addition to analyses of lump samples of these three meteorite, powder samples representing six different portions within Y000593 also were analyzed for discussing the chemical heterogeneity. As a result, it was confirmed that most major elements are homogeneously distributed among Y000593 within an error of ±10%. Chemical compositions of Y000593 and Y000749 are essentially identical within error limits, supporting the suggestion that these meteorites are paired. Compositional similarity is also confirmed between Nakhla and Y000593 (and Y000749), verifying that Y000593 (and Y000749) belong to nakhlites. Based on our PGA data coupled with literature data for Martian meteorites, we propose a diagram used for classifying achondrites and further for grouping into individual groups of Martian meteorites. Although there are some scatterings in B and Cl data, we would propose their abundances in nakhlites to be 3.33 ppm and 80 ppm, respectively. Our H data are systematically higher than their literature data. Although further refinements in our analytical procedure of PGA are required for getting more reliable and accurate values of H in Martian meteorites, it is suspected that some literature values of H contents in Martian meteorites are a little too small

Petrogenesis of Yamato-75032 type diogenites

The Tenth Symposium on Polar Science/Special session: [OA] Antarctic meteorites, Thur. 5 Dec. / 3F Multipurpose conference room, National Institute of Polar Researc

ウンドウブ カツドウ ニ オケル シドウ ホウホウ ニ ツイテ ノ イチコウサツ

本研究では、運動部の生徒の意欲や自主性を生み出すために有効的な指導方法について、Deci、Ryan が提唱する自己決定理論に基づき、「動機づけ」の大切さを、外発的な動機づけと、内発的な動機づけについての比較をもって分析した。さらに、動機づけに対する指導者の役割と影響力について、Mageau、Vallerand らの理論をもとに考察を加えた。そして、その結果として、生徒の意欲や自主性を生み出すためには、動機づけを内発的に高めることへの重要性が明らかとなった。また、動機づけは、個人の心理状態による変化だけではなく、周囲を取り巻く環境によっても変化することから、運動部の活動において、指導者が生徒の動機づけに与える影響の大きさが示されることとなった。今後、指導者による生徒の動機づけの内在化(自律性)を促す行動、環境を整える手法として、自律性支援行動を運動部活動の指導に取り入れ、実践していくことが期待される

イソプレン ソクサ オ ユウスル ショクブツ セイブン ノ ex vivo ユウキ ゴウセイ ト ソノ セイリ カッセイ ノ ヒョウカ

Phytyl quinols, namely acyclic tocopherols, are key intermediates of tocopherol biosynthesis, but their biological activities remain unclear. We therefore investigated the structure-activity relationship of phytyl quinols to apply a chemical biosynthesis design for an antiatherosclerosis drug based on isoprenomics. We have achieved the biosynthesis-oriented synthesis of α- and β-phytyl quinol as an unnatural intermediate, other γ- and δ-phytyl quinol as a natural one. All four phytyl quinols showed almost the same moderate inhibitory activity against low-density lipoprotein oxidation instead of their different degree of C-methylation with character different from tocopherols. In vivo toxicities of phytyl quinols against chick embryo chorioallantoic membrane vasculature were hardly observed. We proposed phytyl quinols were possible antioxidants in plants and animals, like vitamin E

イソプレン ソクサ オ ユウスル ショクブツ セイブン ノ ex vivo ユウキ ゴウセイ ト ソノ セイリ カッセイ ノ ヒョウカ

Phytyl quinols, namely acyclic tocopherols, are key intermediates of tocopherol biosynthesis, but their biological activities remain unclear. We therefore investigated the structure-activity relationship of phytyl quinols to apply a chemical biosynthesis design for an antiatherosclerosis drug based on isoprenomics. We have achieved the biosynthesis-oriented synthesis of α- and β-phytyl quinol as an unnatural intermediate, other γ- and δ-phytyl quinol as a natural one. All four phytyl quinols showed almost the same moderate inhibitory activity against low-density lipoprotein oxidation instead of their different degree of C-methylation with character different from tocopherols. In vivo toxicities of phytyl quinols against chick embryo chorioallantoic membrane vasculature were hardly observed. We proposed phytyl quinols were possible antioxidants in plants and animals, like vitamin E

Membrane translocation of t-SNARE protein syntaxin-4 abrogates ground-state pluripotency in mouse embryonic stem cells

Embryonic stem (ES) and induced pluripotent stem (iPS) cells are attractive tools for regenerative medicine therapies. However, aberrant cell populations that display flattened morphology and lose ground-state pluripotency often appear spontaneously, unless glycogen synthase kinase 3β (GSK3β) and mitogen-activated protein kinase kinase (MEK1/2) are inactivated. Here, we show that membrane translocation of the t-SNARE protein syntaxin-4 possibly is involved in this phenomenon. We found that mouse ES cells cultured without GSK3β/MEK1/2 inhibitors (2i) spontaneously extrude syntaxin-4 at the cell surface and that artificial expression of cell surface syntaxin-4 induces appreciable morphological changes and mesodermal differentiation through dephosphorylation of Akt. Transcriptome analyses revealed several candidate elements responsible for this, specifically, an E-to P-cadherin switch and a marked downregulation of Zscan4 proteins, which are DNA-binding proteins essential for ES cell pluripotency. Embryonic carcinoma cell lines F9 and P19CL6, which maintain undifferentiated states independently of Zscan4 proteins, exhibited similar cellular behaviors upon stimulation with cell surface syntaxin-4. The functional ablation of E-cadherin and overexpression of P-cadherin reproduced syntaxin-4-induced cell morphology, demonstrating that the E- to P-cadherin switch executes morphological signals from cell surface syntaxin-4. Thus, spontaneous membrane translocation of syntaxin-4 emerged as a critical element for maintenance of the stem-cell niche