千葉県君津市川谷地域に露出する中部更新統柿ノ木台層から産出する冷湧水化石群集: その時空分布と共産する自生炭酸塩

金沢大学国際基幹教育院 GS教育系冷湧水性群集が房総半島の中部更新統柿ノ木台層の陸棚相から産出する．群集は，化学合成二枚貝類から排他的になり，著しく13Cに枯渇した自生炭酸塩と共産することから，AOM（嫌気的メタン酸化）に依存していたと考えられる．自生炭酸塩は巣穴壁面と巣穴周囲の堆積物中に沈殿し，巣穴からスナモグリ類の爪化石と糞化石が産出することから，これらはスナモグリ類の巣穴であると考えられる．スナモグリ類はメタン生成帯まで巣穴を堀り，海水を巣穴深部へ供給し，AOMを活性化させることによって巣穴中の硫化水素イオン濃度を上昇させた．溶存酸素濃度が高い巣穴浅部では，硫黄酸化菌が繁茂し，スナモグリ類の食糧となった．巣穴深部では，浮遊する生物源炭酸塩などを核とした針状アラゴナイトが重力方向に沈下して炭酸塩ジオペタル状構造を形成し，巣穴周囲の堆積物中では，リン酸イオン濃度の上昇により高Mgカルサイトが，また硫酸イオンの枯渇によりドロマイトが沈殿した．Cold-seep-dependent molluscan assemblages occur in the outer-shelf facies of the middle Pleistocene Kakinokidai Formation of the Kazusa Group, a forearc basin-fill sequence on the Pacific side of central Japan, in strata corresponding to the interval 707.6-667.0 ka. The assemblages consist exclusively of chemosymbiotic bivalves (lucinids, thyasirids, and solemyids) and are associated with 13C-depleted authigenic carbonates (δ13C = −61.60‰ to −10.96‰ VPDB), which suggest that their main carbon source was anaerobic oxidation of methane (AOM). Authigenic carbonate precipitates are common on burrow walls (mainly acicular aragonite) and the surrounding sediments (mainly micritic high-Mg calcite and dolomite). The burrows are cylindrical, 1.5-3.0 cm in diameter, and >1 m long. Callianassid claws and the trace fossil Palaxius (probable callianassid fecal pellets) in the burrow carbonates suggest that the burrows were produced by sediment-dwelling callianassid decapods.\nWe propose the following formation mechanism of burrows and their related authigenic carbonates. Firstly, callianassids produced deep burrows, penetrating the AOM zone and reaching the methanogenic zone. Methane then seeped into the burrows and AOM occurred in its deeper parts, promoted by a supply of seawater via callianassid activity, resulting in an increase in the concentration of hydrogen sulfide ions. Thiobacteria flourished in the shallower parts of the burrows, which were enriched in dissolved oxygen, and provided a source of food for the callianassids. In the deeper parts of the burrows, acicular aragonite precipitated around suspended carbonate nuclei and sank to the bottoms of the burrows, forming geopetal-like carbonate structures. In the surrounding sediment, high-Mg calcite precipitated in response to an increase in the concentration of phosphate ions (due to the decomposition of organic matter), and dolomite precipitated in response to decreasing concentrations of sulfate ions (caused by active AOM)

Whole outline scanning measurement of internal gear by using CNC gear measuring machine

A three-dimensional probe is mounted on a specialized gear measuring machine whose measurement target is limited on the working flanks. The newly developed measuring machine has a coordinate measuring mechanism, aiming to be a highly versatile and relatively inexpensive measuring machine. According to our previous research, in addition to the working tooth surface, shape data of the root, bottom and tip profiles can be acquired with a single measurement operation. However, the target object for which this developed method has been applied was only the external cylindrical gear. In this paper, we applied and expanded the development method to the internal cylindrical gear and the evaluation of the axial displacement in the same cross-sectional scanning of the internal helical gear are performed

Chiral separation with molecularly imprinted polysulfone-aldehyde derivatized nanofiber membranes

Molecularly imprinted membranes (MIPMs) and molecularly imprinted nanofiber membranes (MINFMs) were prepared from polysulfone with aldehyde (PSf-CHO-05 or PSf-CHO-10) and N- -benzyloxycarbonyl-D-gultamic acid (Z-D-Glu) or N-a-benzyloxycarbonyl-L-glutamic acid (Z-L-Glu) as a print molecule. Those two types of molecularly imprinted membrane, such as MIPMs and MINFMs, incorporated the enantiomer, of which absolute configuration was same as that of the print molecule, in preference to the corresponding antipode. In other words, the membranes imprinted by the D-isomer preferentially adsorbed the D-isomer and vice-versa. Those two types of membrane showed chiral separation ability by membrane transport. Against expectation, transport of the enantiomer less adsorbed in the membrane was selectively transported. The fluxes through the molecularly imprinted nanofiber membranes gave one to two orders of magnitude higher than those of usual molecularly imprinted membranes without depression of permselectivity. The present study demonstrated that molecularly imprinted nanofiber membrane gave high flux without depression of permselectivity. A breakthrough in membrane separation would be realized by adopting molecularly imprinted nanofiber membranes.Peer reviewed: YesNRC publication: Ye

Molecularly imprinted nanofiber membranes for optical resolution

Peer reviewed: NoNRC publication: Ye

Molecularly imprinted nanofiber membranes from modified polysulfone bearing aldehyde moiety

It is of interest to directly convert polymeric materials into molecularly imprinted nanofiber membranes by simultaneously applying an electrospray deposition and an alternative molecular imprinting. The membranes thus obtained was expected to show not only higher permselectivity but also higher flux value. To this end, molecularly imprinted nanofiber membranes were prepared from modified polysulfone bearing aldehyde moiety by adopting enantiomerically pure N-\u3b1-benzyloxycarbonyl-D-glutamic acid (Z-D-Glu) or N-\u3b1-benzyloxycarbonyl-L-glutamic acid (Z-L-Glu) as a print molecule. The fiber diameters of the molecularly imprinted nanofiber membranes thus obtained were 177 \ub1 64 nm. Enantioselective transport was studied by using concentration difference or potential difference as a driving force for membrane transport. The results obtained in the present study suggested that molecularly imprinted nanofiber membranes enhanced both permselectivity and flux, which are generally perceived to show a trade-off relationship. The flux for the present molecularly imprinted nanofiber membranes were about two orders of magnitude higher than the usual molecularly imprinted membranes, while the molecularly imprinted nanofiber membranes also showed permselectivity.Peer reviewed: NoNRC publication: Ye