Observation of machined surface and subsurface structure of hinoki (Chamaecyparis obtusa) produced in slow-speed orthogonal cutting using X-ray computed tomography

First online: 01 January 2015X-ray computed tomography (CT) was applied to non-destructive observation of machined surface and subsurface structure of hinoki (Chamaecyparis obtusa) produced in slow-speed orthogonal cutting. The cutting experiments were conducted under several cutting conditions and the chip formations were observed with a high-speed camera to be classified into four chip types. The difference in the quality of the machined surfaces produced in four types of chip formation was investigated. During type 0 chip formation, the workpiece was cut almost exactly at the path of the cutting edge, so no deformation was found on and beneath the machined surface. During type I chip formation, the direction of the fore-split, which is dependent on the arrangement of cells, determined the machined surface. During type II chip formation, the cutting tool sometimes tore part of the workpiece below the path of the cutting edge and the tore part was then compressed by the tool, remaining on the machined surface. During type III chip formation, part of the workpiece above the path of the cutting edge was compressed by the tool, instead of being removed as a chip, so the compression occurred in wide area. The relationship between the formation of the machining defects such as torn grain or the compressed cells and the way chip is separated, deformed, or removed was clarified in this study

Precipitant-Free Crystallization of Lysozyme and Glucose Isomerase by Drying

Protein crystallization is usually conducted by using precipitants, although the “salting-out” phenomenon is still unclear and complex. Moreover, the addition of precipitants sometimes results in irreversible disordered precipitation of protein molecules. Although precipitant-free lysozyme crystals obtained by centrifugal concentration showed significant changes in three-dimensional structure compared to the structure of salted-out crystals, it was rather difficult to mount crystals from a viscous dense liquid phase after centrifugal concentration, and the quality of the crystals often deteriorated during the mounting process. Here we present novel precipitant-free crystallization methods, which were effective for lysozyme and glucose isomerase. Tetragonal lysozyme crystals were successfully crystallized in a glass capillary simply by drying highly concentrated lysozyme solution in the presence of 0.01 M hydrochloric acid without using any precipitants. Glucose isomerase dissolved in ultra-pure water was also successfully crystallized in hanging drops by drying highly concentrated solution under low-humidity conditions. Oscillation images of the obtained crystals were safely collected without handling; they clearly indicated the crystals had a tetragonal form for lysozyme and an orthorhombic form for glucose isomerase, and their lattice parameters are similar to those of previously reported crystals obtained by salting-out methods

ワセイガク コトハジメ メーソン ノ ワセイガク キョウイク ニ カンスル シン シリョウ ショウカイ

研究論

ワセイガク コトハジメ メーソン ノ ワセイガク キョウイク ニ カンスル シン シリョウ ショウカイ ソノ2

研究論

ワセイガク コトハジメ メーソン ノ ワセイガク キョウイク ニ カンスル シン シリョウ ショウカイ ソノ3

研究論

Effect of horizontal strong static magnetic field on swimming behaviour of Paramecium caudatum

Effect of horizontal strong static magnetic field on swimming behavior of Paramecium caudatum was studied by using a superconducting magnet. Around a center of a round vessel, random swimming at 0 T and aligned swimming parallel to the magnetic field (MF) of 8 T were observed. Near a wall of the vessel, however, swimming round and round along the wall at 0 T and aligned swimming of turning at right angles upon collision with the wall, which was remarkable around 1~4 T, were detected. It was experimentally revealed that the former MF-induced parallel swimming at the vessel center was caused physicochemically by the parallel magnetic orientation of the cell itself. From magnetic field dependence of the extent of the orientation, the magnetic susceptibility anisotropy (χ‖-χ⊥) was first obtained to be 3.4×10-23 emu cell-1 at 298 K for Paramecium caudatum. The orientation of the cell was considered to result from the magnetic orientation of the cell membrane. On the other hand, although mechanisms of the latter swimming near the vessel wall regardless of the absence and presence of the magnetic field are unclear at present, these experimental results indicate that whether the cell exists near the wall alters magnetic field effect on the swimming in the horizontal magnetic field

Delayed Methotrexate Elimination after Administration of a Medium Dose of Methotrexate in a Patient with Genetic Variants Associated with Methotrexate Clearance

Polymorphisms in methotrexate transporter pathways have been associated with methotrexate toxicities and clearance. Recent genome-wide association studies have revealed that the SLCO1B1 T521C variant is associated with methotrexate elimination. We present a case of a pediatric patient with acute lymphoblastic leukemia who suffered from persistently high plasma methotrexate concentrations and acute kidney injuries after the admin-istration of a medium dose of methotrexate. Subsequent genetic analysis showed that he was a carrier of dys-functional genetic variants associated with methotrexate clearance. This case highlights that polymorphisms of methotrexate transporter pathways can adversely affect methotrexate elimination in a clinically significant manner