Showing papers by "Tohoku University published in 1984"

Fractal structures of zinc metal leaves grown by electrodeposition

Abstract: Zinc metal leaves are grown two-dimensionally by electrodeposition. The structures clearly remind us of the random patterns simulated by computer according to the Witten-Sander diffusion-limited-aggregation model. The scale invariance is tested by computing the density-density correlation function for the digitized patterns of the photographs. The Hausdorff dimension averaged over many examples is $D=1.66\ifmmode\pm\else\textpm\fi{}0.03$, which is in excellent agreement with that of the two-dimensional diffusion-limited-aggregation model ($D\ensuremath{\cong}\frac{5}{3}$).

Partition coefficients of Hf, Zr, and ree between phenocrysts and groundmasses

Abstract: Partition coefficients of Hf, Zr, and REE between olivine, orthopyroxene, clinopyroxene, plagioclase, garnet, amphibole, ilmenite, phlogopite, and liquid are presented. Samples consist of megacrysts in kimberlite, phenocrysts in alkaline basalts, tholeiitic basalts and andesitic to dacitic rocks, and synthetic garnet and clinopyroxene in Hawaiian tholeiites. The Hf-Lu and Zr-Lu elemental fractionations are as large as the Lu-Sm or Lu-Nd fractionation. The Hf and Zr partition coefficients between mafic phenocrysts and liquids are smaller than the Lu partition coefficients, but are similar to the Nd or Sm partition coefficients. The Hf and Zr partition coefficients between ilmenite, phlogopite, and liquid are larger than the Lu partition coefficients for these minerals and their corresponding liquids. The Hf-Zr elemental fractionation does not occur except for extreme fractionation involving Zr-minerals and extremely low fO2. These data have an important bearing on chronological and petrogenetic tracer studies involving the Lu-Hf isotopic system.

Design theory of dielectric-coated circular metallic waveguides for infrared transmission

Abstract: A circular metallic hollow waveguide with inner dielectric multilayers is designed with the emphasis on low-loss transmission of the HE 11 mode for the infrared. The effects of absorptions and variations of thickness of coated dielectric materials are discussed and are shown to be small on the minimum attainable transmission losses. Mode structure and transmission properties are also clarified for the general class of hollow waveguides by using a normalized surface impedance and admittance.

Band structure and optical properties of black phosphorus

Abstract: First, the authors calculate the frequency-dependent dielectric function of black phosphorus by using the band structure and wavefunctions obtained by the self-consistent pseudopotential calculation. Then by using these results, they discuss the optical properties of black phosphorus such as KPS, UPS, plasmon frequency and reflectance in visible, VUV and soft X-ray regions. Experimental results for all these optical properties are explained consistently using the theoretical results.

Magnetic Properties of Single Crystals of CexLa1-xB6

Abstract: Measurements of the magnetization process at 4.2 K and 1.3 K for magnetic field up to about 150 kOe and of the temperature dependence of the susceptibility between 4.2 K and room temperature have been done in order to investigate Kondo states of dilute and dense Kondo system in single crystalline Ce x La 1- x B 6 (0.03 ≦ x ≦1.0). The magnetic phase diagram is constructed above 0.6 K for Ce 0.5 La 0.5 B 6 , Ce 0.75 La 0.25 B 6 and CeB 6 . A largely anisotropic magnetization and the temperature dependence of susceptibility in dilute alloys indicate the \(\varGamma _{8}\) quartet Kondo state contrary to the previous report. Dependence of Kondo temperature on the Ce concentration is very weak.

The invariant holonomic system on a semisimple Lie algebra

Abstract: On etudie la theorie geometrique des representations du groupe de Weyl du point de vue des systemes holonomes sur des algebres de Lie

Perpendicular magnetic recording -- Evolution and future

Abstract: This paper reviews research results for the head, medium and recording properties of a perpendicular recording system. Superior bit density characteristics obtained so far indicate that perpendicular recording is basically free from demagnetization in the high density region and that it will establish a new field of recording technology in the future. The prediction is explained in the context of complementary profiles of longitudinal and perpendicular recording. At the very beginning of magnetic recording, a perpendicular-type head was considered but abandoned because a suitable medium did not exist. Progress in material science has enabled us to develop a perpendicular recording medium which is very well suited for ultra high density recording. As so often happens, history has repeated itself through another study of perpendicular recording.

Study on boundary layer transition of a rotating disk

Abstract: Behaviour of spiral vortices being generated in transition regime of a disk rotating in otherwise undisturbed fluid is experimentally studied in detail. Through visualizations of the transition regime by using close-up camera, new striped flow patterns originating along the axis of spital vortices are found to be ring-like vortices which occur on the surfaces of each spiral vortices. Mechanism of the spiral vortex is clarified by cutting the vortices by strobo slit light. It is also found out experimentally that the phase velocity of the vortices is zero.

Characterization of human granular lymphocyte subpopulations expressing HNK-1 (Leu-7) and Leu-11 antigens in the blood and lymphoid tissues from fetuses, neonates and adults.

Abstract: Three subpopulations of human granular lymphocytes from blood and lymphoid tissues were characterized using combinations of the monoclonal antibodies (mAb) HNK-1 (Leu-7), Leu-11 and VEP13. Each subpopulation was confirmed to possess natural killer (NK) cell functional capability, but a different level of cytotoxic efficiency (HNK-1+leu-11- less than HNK-1+Leu-11+ less than HNK-1-Leu-11+). In adult from 23 healthy donors, the subpopulations with HNK-1+Leu-11-, HNK-1+Leu-11+ and HNK-1-Leu-11+ phenotypes comprised 4.7 +/- 3.0, 8.0 +/- 6.4 and 3.9 +/- 3.5% of mononuclear cells, respectively. Despite their distinct surface marker phenotypes and NK functional ability, all 3 subpopulations exhibited granular lymphocyte morphology. One of these subpopulations, HNK-1+Leu-11-, also expressed the pan-T cell antigen Leu-4. Different patterns were observed in fetal bone marrow and cord blood, where the vast majority of HNK-1+ cells lacked the Leu-11 antigen (HNK-1+Leu-11+ cells). The HNK-1 antigen was not expressed on granulocytes and their precursors, whereas both Leu-11 and VEP13 antigens were expressed on these myeloid cells from fetal bone marrow and cord blood as well as adult bone marrow and spleen. Cell lines of granular lymphocytes cultured in the presence of interleukin 2 all possessed the HNK-1+Leu-4+ phenotype and NK functional capability but lacked the Leu-11 and VEP13 antigens on their surface after 15 days of culture. Although granular lymphocytes expressing the Fc receptors reacting with the mAb Leu-11 and VEP13, are the most functionally active NK cells, the HNK-1+ subpopulation lacking the Leu-11 and VEP13 antigens appears to be an important population (possibly an immature form of granular lymphocytes) for delineating the cell lineage(s) and differentiation of human granular lymphocytes. Although none of the currently available mAb react both inclusively and exclusively with human granular lymphocytes, the combination usage of these antibodies permits a more precise and comprehensive analysis of these subsets.

Distribution of HRP in the inner ear after injection into the middle ear cavity.

Abstract: The distribution patterns of horseradish peroxidase (HRP) reaction products in the inner ears of guinea pigs were studied after injections into the middle ear cavities and perilym-phatic and subarachnoid spaces. The normal round window membrane resisted HRP penetration from the middle ear side, but when it became pathological after repeated applications, its permeability increased. HRP deposits were found in the cochlear and vestibular sensory cells and in the lumen of the endolymphatic sac. HRP reaction products were minimal at the cochlear apex even after long survival times, suggesting that peri-lymph flow, if it exists, is rather weak toward this direction. Whereas the stria vascularis is impermeable to HRP, the vestibular dark cells were accessible; thus, the metabolic activity of the dark cells can be more readily controlled by drug applications through the middle ear cavity. The finding of HRP deposits on the scala vestibuli surface of Reissner's membrane and the absence of HRP in the upper portion...

Cystatin S: A cysteine proteinase inhibitor of human saliva.

Abstract: An acidic protein of human saliva, which we named SAP-1 previously, is now shown to be an inhibitor of several cysteine proteinases. The protein inhibited papain and ficin strongly, and stem bromelain and bovine cathepsin C partially. However, it did not inhibit either porcine cathepsin B or clostripain. The mode of the inhibition of papain was found to be non-competitive. The name cystatin S has been proposed for this salivary protein in view of the similarities in activity and structure to other cysteine proteinase inhibitors such as chicken egg-white cystatin and human cystatins A, B, and C. The cystatin S antigen was detected immunohistochemically in the serous cells of human parotid and submaxillary glands.

Properties of porous anodic aluminum oxide films as membranes.

Abstract: The details of a method of preparing anodic aluminum oxide membranes are presented. The porous oxide layer consists of close-packed cells of oxide, hexagonal in shape, each of which contains a single pore formed perpendicularly to the surface of the aluminum substrate. This special structural feature is essentially important for ultrafiltration and gas separation. The rejection characteristics are examined, using aqueous and nonaqueous solutions of macromolecules. The permeability of gases is also examined at different temperatures. The flow of gases is explained by the Knudsen regime alone.

The effect of a grain boundary structural transformation on sliding in -tilt zinc bicrystals

Abstract: The effect of temperature on grain boundary sliding has been studied for tilt boundary, which is slightly off the 56–6° /σ9 near-coincidence orientation relationship. For a 16–5° low-angle tilt boundary, no change in the temperature dependence was observed over the entire test temperature range up to the melting point, and the activation energy for sliding is similar to those for high-angle grain boundaries below Tc. It...

Possible cancerous change of intraductal papillomas of the breast. A 3-D reconstruction study of 25 cases†

Abstract: Surgical specimens from 25 patients with intraductal papilloma were subjected to 3-dimensional (3-D) reconstruction studies of their mammary ducts. Papillomas of the multiple type (15 cases) always originated in the terminal duct lobular units (TDLU), whereas all papillomas of the solitary type (10 cases) originated in the large ducts except for one. In 6 of the 25 (24%) patients ductal carcinomas were accidentally found during specimen reconstruction. Two of the six patients harbored microscopic carcinoma as small as 3 mm or less. Three-D reconstructions revealed that carcinomas with multifocal origins in the TDLUs were connected with peripheral papilloma. Papilloma preceding carcinoma was of the multiple type in five patients, and of the solitary type in one. This study also showed that 6 of the 16 (37.5%) patients with papilloma originating in the periphery had carcinomas, whereas none of the nine patients originating in the center did. This observation strongly suggests that the peripheral papilloma is highly susceptible to cancerous change.

Rat-liver lysosomal sialidase: solubilization, substrate specificity and comparison with the cytosolic sialidase

Abstract: Purified liver lysosomes, prepared from rats previously injected with Triton WR-1339, exhibited sialidase activity towards sialyllactose, fetuin, submaxillary mucin (bovine) and gangliosides, and could be disrupted hypotonically with little loss in these activities. After centrifugation, the activities with sialyllactose and fetuin were largely recovered in the supernatant, demonstrating that they were originally in the intralysosomal space. The activities towards submaxillary mucin and gangliosides, on the other hand, remained in the pellet. In the supernatant, activity with fetuin or orosomucoid was markedly reduced by protease inhibitors, suggesting that proteolysis of these glycoproteins may be prerequisite to sialidase activity. The intralysosomal sialidase was solubilized from the mitochondrial-lysosomal fraction of rat liver and partially purified by Sephadex G-200, or Sephadex G-200 followed by CM-cellulose. The enzyme was maximally active at pH 4.7 with sialyllactose as substrate and had a minimum relative molecular mass of 60000 ± 5000 by gel filtration; if hydrolyzed a variety of sialooligosaccharides, those containing (α2 3)sialyl linkages being better substrates than those with (α2 6)sialyl linkages. The enzyme failed to attack submaxillary mucin and gangliosides. It was also inactive towards fetuin, orosomucoid and fransferrin but capable of hydrolyzing glycopeptides from pronase digest of fetuin. In contrast to the intralysosomal silaidase, the sialidase partially purified from rat liver cytosol by (NH4)2SO4 fractionation followed by chromatography on DEAE-cellulose and CM-cellulose hydrolyzed fetuin and orosomucoid to the extent about half that for sialyllactose. The enzyme was maxitoally active at pH 5.8 and had a relative molecular mass of approximately 60000. It also hydrolyzed gangliosides but not submaxillary mucin.

Infrared absorption enhancement of monolayer species on thin evaporated Ag films by use of a Kretschmann configuration: evidence for two types of enhanced surface electric fields

Abstract: Infrared absorption enhancement of m- and p-nitrobenzoic acid deposited on thin-evaporated silver films has been investigated using the Kretschmann's ATR coupling method. The absorption spectra provide direct evidence that enhancement is prominent only for vibrations of the first monolayer adsorbed on the Ag surface. It is shown that all of the vibrational modes observed obey the normal dipole selection rule. Moreover, it was found that there exist two types of absorption enhancement; the first is enhanced (∼300) by both p- and s-polarized radiation, and the second is enhanced (∼60) by p-polarized radiation alone. The Ag film thickness optimum is about 50 A in the former case and about 200 A in the latter. The enhancement insensitive to the polarization state of radiation can well be explained by the excitation of the transverse collective electron resonance of the Ag islands, whereas that obtained by p-polarized radiation may be due to the excitation of delocalized surface plasmons modified by surface roughness. The image-dipole effect may also be significant in the mechanisms.

Epstein–Barr virus transforms precursor B cells even before immunoglobulin gene rearrangements

Abstract: The very early stages of the human B-cell differentiation pathway are poorly understood, primarily because of the lack of appropriate permanent cell lines. Epstein–Barr virus (EBV) is a putative human oncogenic virus which transforms human B cells in vitro into continuously proliferating cells1. It has been believed that EBV transforms mature B cells2,3 but recently, transformation of immature pre-B-cell lines has been reported4–6, suggesting that EBV might also transform cells much earlier in the B-cell lineage. We report here the establishment of cell lines transformed by EBV at various stages of the B-cell differentiation pathway. Interestingly, two lines showed the complete absence of immunoglobulin synthesis and the lack of immunoglobulin gene rearrangement despite containing EBV genome and surface markers of B cells. Our results indicate that EBV can infect and tranform cells of the B lymphocyte lineage even before immunoglobulin gene rearrangement.

Magnetic Phase Diagram of MnSi near Critical Temperature Studied by Neutron Small Angle Scattering

Abstract: The magnetic phase diagram of MnSi near the critical temperature T N =29.5 K has been studied by neutron small angle scattering at KENS. It has been found that the anomalous new phase predicted by various methods to exist around at 28 K and 2 kOe is the paramagnetic phase where the magnetic correlations exhibit the same characteristics as those found at 29.5 K and zero magnetic field. This phenomenon, together with the sharp decrease of the magnetic phase boundary at T N and the substantial increase of the satellite Q vector at this temperature, has been found not to be interpreted by the current theories.

Crystalline Phase Change in Yttria‐Partially‐Stabilized Zirconia by Low‐Temperature Annealing

Abstract: Changes in the phase composition and microstructure of yttria-partially-stabilized zirconia by low-temperature annealing were investigated at 100° to 500°C using bodies sintered from coprecipitated fine ZrO2-Y2O3 powders at varied temperatures. Tetragonal zirconia on the surfaces of bodies sintered at <1500°C transformed to the monoclinic phase at 100° to 400°C. Transformation behavior was strongly affected by grain size.

Mass Screening for Gastric Cancer by X-Ray Examination

Abstract: The characteristics of early gastric cancer detected by gastric mass survey were examined. The progress of the screening test using the indirect X-ray examination and the tendency toward reduction in mortality from stomach cancer were evaluated. In 1981 the number of examinees in the gastric mass surveys amounted to over four millions in all Japan. From the data of the gastric mass survey in Miyagi Prefecture the rate of detection of gastric cancer was approximately 0.18% and the ratio of early cancer to surgically treated gastric cancer was 59.4% for 1980-1982. Furthermore, the number of m cancer, small cancer and minute cancer cases detected by the survey has increased year by year. These results are due to various advanced screening tests or close examination techniques. From our long-term follow-up study it is clearly indicated that the rate of deaths from stomach cancer in the screened individuals was half of the rate in the unscreened individuals.

New low-loss SAW filter using internal floating electrode reflection types of single-phase unidirectional transducer

Abstract: A new single-phase unidirectional transducer utilising the difference between excitation and reflection positions caused by the floating electrodes of open and short metal strips inserted into the interdigital transducer within a half wavelength is described.