Kazuya Mori

Xenopus PKN: cloning and sequencing of the cDNA and identification of conserved domains

cDNA clone encoding Xenopus laevis PKN has been isolated from Xenopus kidney library. Sequencing of this clone has revealed a single open reading frame encoding a protein of 901 amino acids. Immunoprecipitate from cytoplasmic fraction of COS7 cells transfected with this cDNA construct using antiserum against bacterially expressed Xenopus PKN revealed arachidonic acid-dependent autophosphorylation activity. Comparison of the closely related sequences of human and rat PKN with a protein from evolutionarily distant Xenopus, revealed several highly invariant domains in the NH2-terminal regulatory regions, suggesting that they participate in binding interaction with arachidonic acid.

Magnetic shielding effects of the superposition of a ferromagnetic cylinder over an HTS cylinder: magnetic shielding dependence on the air gap between the BPSCCO and soft-iron cylinders

Abstract Ideal magnetic shielded vessels can be realized by making use of a high-critical temperature superconductor (HTS). Use of such shielding does not, however, generally satisfy the maximum shielded magnetic flux density B s required of an HTS vessel for practical applications. The present authors have improved the value of B s by the superposition of a ferromagnetic cylinder over an HTS cylinder, termed the superimposed cylinder. The evaluation of the magnetic shielding effects was limited to the superimposed cylinder, in order to simplify the theoretical analysis. Nevertheless, little is known of the resulting characteristics and evaluation procedures when changing the size of the air gap δ between the HTS and ferromagnetic cylinders for applications of an external magnetic field B ex less than the value of B s . The values of B s were systematically measured by for different values of δ , and in addition, were theoretically analyzed. It was found that the experimental values of B s agreed well with theoretical values. Furthermore, measurements were taken of the magnetic noise power spectrum for various values of δ , with the use of the HTS dc-SQUID system and spectrum analyzer. From these results, the characteristics of the magnetic behavior for different values of δ within the superimposed cylinder were clarified. In addition, an important criterion is discussed for the design of an effective magnetic shielding vessel.

Characteristics of a highly sensitive magnetic sensor constructed of a thick HTS film

For use in constructing highly sensitive magnetic sensors, the present authors have been studying the preparation of thick Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) films. In this research, thick YBCO film was fabricated as the magnetic sensor, constructed to retain a residual resistance R/sub res/ at the boiling point of liquid nitrogen (77.4 K). The resistance R/sub ms/ of the magnetic sensor, in the transition region /spl Delta/T, is found to be highly sensitive to the applied magnetic field B/sub ex/, where /spl Delta/T is the region of temperatures between the resistance drop T/sub c//sup onset/ and residual resistance T/sub c//sup res/ temperatures. Under temperature conditions of 77.4 K, the value of R/sub ms/ for this sensor (1.5 mm in width, 67 mm in length, and 280 /spl mu/m thick) for an applied B/sub ex/ of 80/spl times/10/sup -4/ T, increased by factor of 5.8 times greater than that in the absence of a magnetic held. In addition, no evidence was found of the existence of hysteresis in the R/sub ms/ vs B/sub ex/ characteristics for weak values of B/sub ex/. The present paper examines the fabrication conditions and magnetic responses of the highly sensitive sensor constructed of a thick YBCO film.

Magnetic shielding of the superposition of a hybrid ferromagnetic cylinder over a BPSCCO cylinder

The value of the maximum shielded magnetic flux density (B/sub s/) for a high critical temperature superconductor (HTS) cylinder was shown to be improved by the superposition of a hybrid ferromagnetic cylinder over a Bi-Pb-Sr-Ca-Cu-O (BPSCCO) cylinder. This was termed the hybrid BPSCCO superimposed cylinder. The value of B/sub s/ for the hybrid BPSCCO superimposed cylinder was found to be about 52 times greater than that of a single-BPSCCO cylinder. The value of B/sub s/ was analyzed with the use of several different models. It was found that the theoretical values of B/sub s/ agree well with experimental values. The results confirm that an important criterion was determined for use in the design of an effective shield for large chambers.

Highly Sensitive Magnetic Sensor Constructed with a YBCO Thick Film

In the present research, use was made of a Y-Ba-Cu-0 (YBCO) thick film to construct a highly sensitive magnetic sensor using the spray technique. The YBCO magnetic sensor was fabricated to retain a residual resistance R res at the boiling point of liquid nitrogen (77.4 K). The value of resistance R res for the magnetic sensor, in the transition region ΔT of the thick film, was highly sensitive to the excitation magnetic field B ex. Here, ΔT is the region between the transitional temperature T c onset and residual resistance temperature T c onset. The value of R ms for an applied magnetic field of 50 × 10-4 T (= 50 gauss) exhibited an increase to a value of about 680% greater than the resistance found in a zero magnetic field, and did not display any evidence of hysteresis. The present paper examines the fabrication conditions and magnetic responses of a highly sensitive sensor constructed with a YBCO thick film. In addition, a study was done on the characteristics of a magnetic measuring system that uses this sensor.

Magnetic shielding effects by the superposition of a six-layered ferromagnetic cylinder over a BPSCCO cylinder

The maximum shielded magnetic flux density (Bs) was shown to be improved by the superposition of a six-layered ferromagnetic cylinder over a Bi-Pb-Sr-Ca-Cu-O (BPSCCO) cylinder; termed the six-layered superimposed cylinder. The values of Bs for the six-layered superimposed cylinder were found to be about 100 times greater than that of a single-BPSCCO cylinder. The values of Bs were analyzed by using several different models. It was found that the experimental values of Bs agree well with theoretical values. The results confirm that an important criterion was determined for the design of an effective shield for large chambers.

Improvement of the magnetic shielding effect by the superposition of a double-magnetic cylinder over a double-BPSCCO cylinder

Abstract As one of the basic research areas for the improvement of magnetic shieldingeffects and the fabrication of large-size cylinders, the present paper shows how the shielding is improved by superimposing a magnetic double-cylinder over a superconducting Bi Pb Sr Ca Cu O (BPSCCO) double-cylinder. The value of the maximum shielded magnetic field ( B s ) for this superimposed cylinder was found to be about 60 times that of BPSCCO single-cylinder. The value of B s was analyzed by using several different models. In addition, it was found that the experimental values of B s agree well with theoretical values.

Evaluation of the magnetic field within a BPSCCO cylinder superimposed by multi-layered soft-iron cylinders by use of an HTS DC-SQUID

The evaluation of the maximum shielded magnetic flux density B/sub s/ of a high-critical temperature superconducting (HTS) cylinder acting as a magnetic shielding vessel, is required to improve the value of B/sub s/ for practical use. The authors have improved the value of B/sub s/ by the superposition of multi-layered soft-iron cylinders over a Bi-Pb-Sr-Ca-Cu-O cylinder which is termed the superimposed cylinder. Little is known, however, of the characteristics and evaluation procedures for the magnetic flux density B/sub ia/ within the innermost of the superimposed cylinders when the value of the external magnetic flux density B/sub ex/ is less than that of B/sub s/. The present research has evaluated the shielding effect for the superimposed cylinder with the use of an HTS DC-SQUID magnetometer and spectrum analyzer. The present paper examines the magnetic step response of B/sub in/ to the applied B/sub ex/, the characteristics of B/sub in/ when exposed to a B/sub ex/ having a value less than that of B/sub s/, and the magnetic noise power spectra within the superimposed cylinder. In addition, a discussion is conducted on the relationship between the number of layers of the multi-layered soft-iron cylinder and the value of B/sub in/.

Effect of glycosidase inhibitors on the biosynthesis of α2-plasmin inhibitor and antithrombin III in Hep G2 cells☆

We studied the effect of the glucosidase I inhibitor, N-methyl-1-deoxynojirimycin (MdN) and the mannosidase inhibitor, 1-deoxymannojirimycin (dMM) on the biosynthesis and secretion of alpha 2-plasmin inhibitor (alpha 2-PI) and antithrombin III (ATIII) in cultures of human hepatoma (Hep-G2) cells. Incubation with 1 mM MdN decreased secreted alpha 2-PI activity and antigen levels by about 40%, whereas those of ATIII were not affected. Neither inhibitor affected the messenger RNA levels as determined by Northern blotting. Pulse-chase studies using [35S]-methionine showed that MdN decreased alpha 2-PI and ATIII secretion rates. By the 18 h chase, MdN had decreased secreted alpha 2-PI to 50-60%, with little effect on ATIII. Intracellular forms of alpha 2-PI or ATIII synthesized by cells treated with 1 mM MdN were sensitive to endoglycosidase H (Endo H), whereas almost all the secreted forms were resistant, suggesting the presence of complex-type oligosaccharides. In the presence of 1 mM dMM, cells synthesized Endo H-sensitive alpha 2-PI and ATIII with similar secretion rates. These results suggest that retention of glucose on N-linked oligosaccharides not only retards the exit of alpha 2-PI and ATIII, but also changes the catabolic rate of alpha 2-PI in the endoplasmic reticulum.

Magnetic shielding effects for the superposition of multi-layered soft-iron cylinders over a BPSCCO cylinder: Relationship between the shielding effect and the layer number of the soft-iron cylinder

For practical use, it is often necessary to improve the value of the maximum shielded magnetic flux density Bs, of high-critical temperature superconductor (HTS) vessels. Accordingly, the present authors have improved the value of Bs for a Bi-Pb-Sr-Ca-Cu-O (BPSCCO) cylinder used as the shielding vessel, by the superposition of multi-layered soft-iron cylinder over the BPSCCO cylinder. The behavior of the magnetic flux density Bin within the superimposed cylinder, however, for an applied excitation magnetic flux density Bex having values less than that of Bs, has previously been unknown. To rectify this, the present research examines and clarifies the magnetic behavior at the center of the superimposed cylinder, measured with the use of an HTS dc-SQUID magnetometer and spectrum analyzer. Experimental results reveal several characteristics of the magnetic shielding within the superimposed cylinder, including the effects of a region BBF where the values of Bin are not dependent on the applied Bex, but are de...