Environmental effects on the mechanical properties of Co3Ti containing boron,carbon and beryllium

The environmental effects on Co₃Ti polycrystals doped with boron, carbon and beryllium were investigated by tensile testing in air at 293 to 1173 K and the results were compared with those tested in vacuum. The yield stresses of the alloys observed were independent of the test environment. The elongation and ultimate tensile strength of the alloys observed were strongly dependent on the test environment and also the test temperatures. Ductility losses were found for the samples which were tested in air at temperatures below 473 K. The losses were accompanied by a change in fracture mode from transgranular to intergranular. It was suggested that this embrittlement was due to the hydrogen absorbed from air. Neither species boron, carbon nor beryllium were observed in this work to affect the environmental effects on the ductility behaviour of Co₃Ti alloys.     

Enzymatic enantioselective hydrolysis of acyloxyferrocenophanes using lipases and esterases

Enantioselective hydrolysis of racemic acetate or butyrates of 1-hydroxy [3](1,1′) ferrocenophane and endo-1-hydroxy [4](1,2) ferrocenophane using lipases, pig liver esterase and horse liver esterase resulted in the formation of (R)-alcohols and (S)-esters.     

Promotion of practical SIMOX technology by the development of a 100 mA-class high-current oxygen implanter

A high-current oxygen implanter which has an acceleration energy of 200 keV and a beam current of 100 mA has been developed. This implanter has been used to form SIMOX wafers, on which p- and n-channel MOSFETs have been fabricated on a trial basis. Good electrical characteristics have been achieved with these MOSFETs. It has been shown that a 100 mA-class high-current oxygen implanter can promote SIMOX technology in a practical way.     

Chemical Synthesis of a Synthetic Analogue of the Sialic Acid‐Binding Lectin Siglec‐7

As a basis for the development of an artificial carbohydrate‐binding lectin, we chemically synthesized a domain of siglec‐7, a well‐characterized sialic‐acid‐binding lectin. The full polypeptide (127 amino acids) was constructed by sequential native chemical ligation (NCL) of five peptide segments. Because of poor cysteine availability for NCL, cysteine residues were introduced at suitable ligation sites; these cysteine residues were alkylated in order to mimic native glutamine or asparagine residues, or converted to an alanine residue by desulfurization after NCL. After folding the full‐length polypeptide, the sialic‐acid‐binding activity of the synthetic siglec‐7 was clearly demonstrated by STD NMR and ELISA experiments. We succeeded in the synthesis of siglec‐7 by installing three extra cysteine residues with side‐chain modifications and found that these modifications did not affect the binding activity.     

950 keV, 3.95 MeV and 6 MeV X-band linacs for nondestructive evaluation and medicine

We are developing compact X-band linac X-ray sources for nondestructive evaluation and medicine. First, we develop a portable X-ray system by a 950 keV 9.4 GHz X-band linac to realize on-site inspection. We use a low power (250 kW) magnetron as an RF source for compactness of the whole system. Since the RF power source is quite small and the stored energy in the structure is also small, we faced the problem of beam loading and current/RF-power oscillation. We are analyzing the problem by the circuit model. We plan to use this system for erosion inspection of metal pipes of petrochemical complex. By adopting a side-coupling cavity design to avoid the oscillation, we have developed 6 MeV X-band (9.3 GHz) linac for pinpoint dynamic tracking cancer therapy. Furthermore, we are manufacturing 3.95 MeV X-band (9.3 GHz) linac X-ray source with flexible waveguides for on-site bridge inspection. Updated results and situations are presented.     

Zinc oxide-coated plasmonic chip modified with a bispecific antibody for sensitive detection of a fluorescent labeled-antigen

A plasmonic biosensor chip of silver-coated PMMA grating with a zinc oxide (ZnO) overlayer is fabricated for surface plasmon field-enhanced fluorescence (SPF) detection of Cy5-labeled green fluorescent protein (GFP). A bispecific antibody (anti-GFP x anti-ZnO antibody) prepared in our lab is densely immobilized on the sensor chip for GFP detection. The sensitivity of the plasmonic biosensors is improved due to densely packed antibodies and ZnO-coating that suppresses nonspecific protein adsorption and fluorescent quenching. With the ZnO-coated plasmonic chip, Cy5-labeled GFP of 10 pM can be detected through SPF. This sensitivity is 100 higher compared with the normal fluorescent detection on a ZnO-coated glass slide.     

Environmental effect on mechanical properties of recrystallized L12-type Ni3(Si,Ti) intermetallics

The environmental effect on the mechanical properties of boron-doped and undoped Ni₃(Si, Ti) polycrystals was investigated by tensile testing in air from room temperature to 1073 K, and the results were compared with those obtained previously by tensile testing in vacuum. The environmental effect for the Ni₃(Si, Ti) alloys was significant at ambient temperatures whereas that for the boron-doped Ni₃(Si, Ti) alloys was considerable at elevated temperatures. When these samples at associated temperatures were tensile tested in air and also at low strain rate, intergranular fracture was dominant. It was suggested that the environmental embrittlements at low and high temperatures were due to hydrogen and oxygen absorbed from the air, respectively, and were caused by the weakening of the grain-boundary cohesion. It was proposed that boron competing with hydrogen, for site occupation or for its effectiveness at grain boundaries, has the effect of suppressing hydrogen embrittlement, whereas it was suggested that the low-melting phases, consisting of boron and oxygen (and/or constituent atoms), may be responsible for the ductility loss in the boron-doped Ni₃(Si, Ti) alloys.     

Bradykinin stimulates type II alveolar cells to release neutrophil and monocyte chemotactic activity and inflammatory cytokines

In the present study, we evaluated the potential of bradykinin (BK) to induce the release of neutrophil and monocyte chemotactic activity (NCA and MCA) and cytokines from an alveolar type II epithelial cell line, A549 cells. BK stimulated A549 cells to release NCA and MCA in a dose- and time-dependent manner (P < 0.001). Checkerboard analysis revealed that both NCA and MCA involved chemotactic and chemokinetic activity. Molecular sieve column chromatography showed three molecular weight masses (near 19 kd, 8 kd, and 400 d) for NCA and several molecular weight peaks (near 66 kd, 25 kd, 19 kd, 16 kd, and 400 d) for MCA. The release of NCA and MCA was inhibited by cycloheximide and lipoxygenase inhibitors (P < 0.01). The NCA and MCA were inhibited by leukotriene B4 (LTB4) receptor antagonist (P < 0.01), and the concentration of LTB4 was high enough for NCA and MCA. Antibodies to interleukin (IL)-8 and granulocyte colony-stimulating factor (G-CSF) attenuated NCA (P < 0.01), and antibodies to monocyte chemotactic protein-1 (MCP-1), G-CSF, and transforming growth factor (TGF)-beta attenuated MCA (P < 0.01). The levels of IL-8, G-CSF, MCP-1, and TGF-beta increased time dependently (P < 0.01). BK also stimulated the release of ILeukin-6 from A549 cells (P < 0.001). The receptors responsible for the release of NCA, MCA, and individual chemokines involved both BKB1 and BKB2 receptors. These data suggest that BK may stimulate alveolar type II pneumocytes to release inflammatory cytokines, which then may modulate the lung inflammation.     

Clinical features of anterior inferior cerebellar artery territory infarcts--a study of ten patients

Clinical features of the anterior inferior cerebellar artery (AICA) territory infarcts were investigated in ten patients, ranging in age from 38 to 76 years. In all patients, there were MR images of infarction located in the area supplied by the AICA. The lesion was on the left side in 6 patients and right side in 4. The lesion of brain stem including the middle cerebellar peduncle was found in 7 patients and that extended to the cerebellum was in 3 patients. The main ipsilateral neurological signs were the VII and VIII cranial nerves palsy and cerebellar ataxia. The V and VI cranial nerves palsy. Horner's syndrome, and dysphagia were also present. The main contralateral sign was superficial sensory disturbance, but no hemiplegia. The underlying pathology included chiefly hyperlipidemia, hypertension, and diabetes mellitus. Cerebral angiography was performed in 8 patients, most of which was observed severe arteriosclerosis suggesting poor hemodynamics in the vertebral and basilar arteries. The prognosis was relatively good, but the VII, VIII, and V cranial nerves palsy and contralateral superficial sensory disturbance remained as the sequelae. As mentioned above, there were various neurological findings and MR images in AICA territory infarcts. Especially there were some patients whose lesion extended to the upper medulla and neurological findings were similar to the Wallenberg syndrome. It is important that one investigates not only axial slices but also coronal slices of MR image to estimate the extension of AICA territory infarct.