Antitumor activity of degraded products of lentinan: its correlation with molecular weight

Twelve of 25 patients with mixed connective tissue disease complained of xerostomia and/or ocular symptoms of keratoconjunctivitis sicca. In addition to the clinical features of mixed connective tissue disease, all 12 patients had high titers of antibody to the ribonuclease-sensitive component of the extractable nuclear antigen. Eight patients had both clinical xerostomia and keratoconjunctivitis sicca, one had keratoconjunctivitis sicca and salivary gland enlargement, while there had xerostomia but no ocular complaints. Sj?rgren's syndrome was confirmed in all 12 patients by means of Schirmer's tests, Rose Bengal staining tests, salivary gland scintiscans, radionuclide excretion studies in saliva, parotid sialographies, and lip biopsies. At least three of these tests were abnormal in all patients.     

Effect of titanium,niobium and zirconium on creep rupture strength and ductility of cobalt base superalloys

An attempt has been made to develop a cobalt base casting superalloy (30Cr-10Ni-7W-Co) having high creep rupture strength and ductility for first stage nozzles of gas turbines. In cobalt base superalloys, there was found to exist a close correlation between the creep rupture strength and MC type carbide forming elements such as Ti, Nb and Zr. In cobalt base alloys with 0.25 wt pct C, precipitation and coarsening of carbides can be reduced by addition of Ti, Nb and Zr. Therefore, by adding the optimum amount of Ti, Nb and Zr, precipitation of carbides in the alloy reaches such an amount as to give the highest creep rupture strength. Excess addition of Ti, Nb and Zr does not improve the creep rupture strength. By adding C, creep rupture strength of the cobalt alloy with Ti, Nb and Zr can be improved and becomes the highest at 0.40 wt pct. C. According to the experimental results, the creep rupture strength becomes the highest at a value of (Ti + Nb + Zr)/C (atomic ratio) of about 0.3. Contrary to the expectation, it was found in this experiment that the ductility in creep rupture tests increases with increasing carbon content up to 0.6 wt pct.     

TTT System (50 Mbits/s PCM-TDMA System With Time Preassignment and TASI) and Its Satellite Test Results

An experimental 50 Mbits/s pulse-code modulation-time-division multiple access (PCM-TDMA) system with time preassignment and time-assignment speech interpolation (TASI) features (called the TTT system) was built for use in a satellite test. This system was designed for application in the INTELSAT IV network and has the channel capacity of more than 700 telephone channels. This capacity can be increased up to twice when pulse-code modulation-time-assignment speech interpolation (PCM-TASI) is adopted. The field test was conducted via INTELSAT III in 1970 and satisfactory results were obtained, which encourages the introduction of the TDMA system for commercial use.     

Influence of the image quality deterioration of a tilted thick specimen on electron tomography

In electron tomography (ET) based on a transmission electron microscope, the effective thickness of a specimen increases with the tilt angle and, therefore, the projection quality may deteriorate because of electron scattering. The information-missing region, however, can be reduced by broadening the specimen tilt range. To clarify the general influence of these effects on ET, the projection quality varying with the tilt angle was quantitatively evaluated for a 5-microm thick specimen observed with a 3 MV ultrahigh-voltage electron microscope. Simulations of three-dimensional reconstruction were then performed for different specimen thicknesses and tilt ranges. As a result, the ET accuracy was shown to decrease as the specimen thickness increased. However, an optimum specimen-tilt range, at which ET could reach its highest accuracy, was found to exist and become small with the increase of the specimen thickness. The presented results are helpful for determining the specimen thickness limitation on the ET resolution and improving the ET fidelity of thick specimens.     

Syntheses and properties of B-C-N and BN nanostructures

The current status of research on boron-carbon-nitrogen (B-C-N) and boron nitride (BN) nanotubes is presented. The latest achievements in syntheses, analyses and property measurements of these nanoscale tubular architectures are reviewed. The characteristic features of B-C-N and BN nanotubes, compared with conventional C nanotubes, are paid special attention. In particular, the latest breakthroughs in the chemical vapour deposition synthesis of BN nanotubes and an insight into their unique structures are highlighted. A wide range of potential applications is also envisaged, based on the recent progress, which includes pioneering results in BN nanocable fabrication, gas adsorption, electron transport and field emission measurements.     

Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel junctions

The tunnel magnetoresistance (TMR) effect in magnetic tunnel junctions (MTJs) is the key to developing magnetoresistive random-access-memory (MRAM), magnetic sensors and novel programmable logic devices. Conventional MTJs with an amorphous aluminium oxide tunnel barrier, which have been extensively studied for device applications, exhibit a magnetoresistance ratio up to 70% at room temperature. This low magnetoresistance seriously limits the feasibility of spintronics devices. Here, we report a giant MR ratio up to 180% at room temperature in single-crystal Fe/MgO/Fe MTJs. The origin of this enormous TMR effect is coherent spin-polarized tunnelling, where the symmetry of electron wave functions plays an important role. Moreover, we observed that their tunnel magnetoresistance oscillates as a function of tunnel barrier thickness, indicating that coherency of wave functions is conserved across the tunnel barrier. The coherent TMR effect is a key to making spintronic devices with novel quantum-mechanical functions, and to developing gigabit-scale MRAM.     

Metabolic disturbance of tryptophan-nicotinamide conversion pathway by putative endocrine disruptors, bisphenol A and styrene monomer

Bisphenol A, a monomer of polycarbonate plastics, disturbed the conversion pathway of the amino acid tryptophan to the vitamin nicotinamide. The conversion ratio of tryptophan to nicotinamide was reduced to 1/15 by feeding a diet containing 1% bisphenol A. A putative disturbing reaction is kynurenine-->3-hydroxykynurenine, which is catalyzed by kynurenine monohydroxylase. This is an FAD-enzyme and requires NADPH as a coenzyme. Styrene monomer (1% addition to a normal diet) did not affect the food intake or the body weight, but slightly reduced the conversion ratio of tryptophan-nicotinamide.     

Three-dimensional expression of adhesion molecules on the superficial synovial intima of LPS-induced arthritis of the mouse knee analyzed by immuno-SEM

Three-dimensional microlocalization of adhesion molecules, i.e. ICAM-1 (intercellular adhesion molecule), VCAM-1 (vascular adhesion molecule), LFA-1 (lymphocyte function-associated antigen), Mac-1 (macrophage differentiation antigen) and VLA-4 (very late activation antigen), expressed on type-A synoviocyte (macrophage-like cell) and type-B synoviocyte (fibroblast-like cell), were detected by immuno-scanning electron microscopy (SEM) to investigate the immunoreactive microenvironment of the superficial synovial intima in lipopolysaccharide (LPS)-induced arthritis of the mouse knee. Type-B synoviocytes extended rich slender processes from the periphery and constructed a cytoplasmic network, to which ICAM-1 was restricted. VCAM-1 was expressed only in the LPS-stimulated group and was relatively limited to the microvilli of type-B synoviocytes. Type-A synoviocytes were located randomly among the network with a smoother surface and expressed Mac-1 and LFA-1, which were counter-receptors for ICAM-1, and VLA-4 for VCAM-1 on the microvilli or lamellipodia. Three-dimensional microlocalization of adhesion molecules suggests that the network constructed by cytoplasmic processes and microvilli of type-B synoviocytes forms the pathway for the migration or the foothold for the fixation of type-A synoviocytes and takes part in forming an immunoreactive environment in the articular cavity.