Search

In this paper, we propose new applications of bulk high-temperature superconductors in high magnetic fields. High-temperature superconductors, such as Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+d/ (BSCCO) or YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO), maintain their superconductivity over 30 T at 4.2 K. A field-cooled superconducting hollow cylinder traps the magnetic flux inside it. An increase of the applied magnetic field induces shielding current in the interior of the cylinder to maintain the magnetic flux constant. By suitably arranging the cylinders, we can concentrate the magnetic flux and enhance the gradient of the magnetic field. In order to confirm these concepts, we performed experiments using bulk YBCO hollow cylinders. The cylinders are made of YBa/sub 2/Cu/sub 3/O/sub 7-x/ quasi single-crystals containing Y/sub 2/BaCuO/sub 5/ particles. They have an inner diameter of 5 mm, an outer diameter of 10 mm, and a height of 10 mm. Using three hollow cylinders, a magnetic concentration of 0.49 T was observed in an applied magnetic field of 10.14 T. The energized hollow cylinder with a shielding current modify surrounding magnetic fields and magnetic force fields. A magnetic force field enhanced by using a hollow cylinder was calculated numerically for an applied magnetic field of 10 T and estimated to exceed 6000 T/sup 2//m.

A rapid heating and quenching (RHQ) operation along a long-length of jellyroll Nb/Al precursor over 300 m has been established. The J/sub c/ varies sensitively with the joule-heating current (I/sub RHQ/) that determines the temperature from which a precursor wire is quenched, excluding the "plateau" region where the bcc supersaturated-solid solution (Nb(Al)/sub ss/) only forms. The RHQ operation using such a plateau condition can suppress a scatter of J/sub c/ from point to tail of a long-length of wire. The standard deviation of J/sub c/ (4.2 K) at 21 T along a long-length of wire was about 5%, which was less than the variation of J/sub c/ with I/sub RHQ/ in the plateau region (/spl plusmn/7%). The mechanical deformation process needed when incorporating the Cu stabilizer also plays an important role in ensuring uniform heat treatment of the coil that is wound with a long-length of wire and, hence, large heat capacity. Although a temperature ramp-up rate might differ from place to place in the coil, the deformation processing makes such a ramp-up rate insensitive to these critical parameters. The coils using 300.5 m and 254 m lengths of Cu-clad RHQT JR Nb/sub 3/Al conductor generated additional 2.3 T and 3.2 T in bores of 90.2 mm/spl phi/ and 64.6 mm/spl phi/, respectively, indicating that a long-length of RHQT JR Nb/sub 3/Al conductor can be trustworthy for practical coil applications.

As a milestone in the 1-GHz NMR magnet project that is being carried out at the Tsukuba Magnet Laboratory (TML), a 920-MHz high-resolution NMR magnet was successfully manufactured. It is made of 15%Sn-bronze-processed (Nb, Ti)/sub 3/Sn, Ta-reinforced (Nb, Ti)/sub 3/Sn, and NbTi conductors. The room-temperature bore of the cryostat is 54 mm in diameter. All the coils are cooled with pressurized superfluid helium at 1.55 K. The magnet was moved to a new building of the TML in December 2001. A persistent operation at 920 MHz started in April 2002. The field homogeneity after correcting with superconducting shim coils was less than 0.1 ppm in a sample volume. Field decay decreased to below 1.3 Hz/h at the beginning of July. NMR measurements using this magnet started in July.

The field stability of high-field resistive magnets is generally inferior to that of superconducting magnets. The main reason for this is the low inductance of resistive magnets. High-precision measurements, such as those conducted using nuclear magnetic resonance, are very difficult by using high-field resistive magnets due to lack of field stability and ripples in the magnetic fields. However, recent progress in the area of high-temperature bulk superconductors indicates that it is possible to drastically improve these measurements. We used a YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) bulk cylinder made by the Nippon Steel Corporation. Its dimensions were 5 mm (inner diameter)/spl times/10 mm (outer diameter)/spl times/10 mm (height). A pickup coil was inserted into the center of the cylinder to measure ripples in the magnetic field. The bulk cylinder with the pickup coil was then inserted into a resistive magnet of the Tsukuba Magnet Laboratory. At a certain field, the bulk superconductor was cooled down from room temperature to the superconducting state. The signals of the pickup coil before and after transition to the superconducting state were compared.

It is the time resource that one deals with in scheduling. The task is how one can achieve the optimal allocation of a given time resource over a set of assigned activities. Most of the existing scheduling methods use a parametric time by which the activities are orderly allocated in accordance with the order of events. The parametric methods, however, fail in incorporating a dynamic aspect of scheduling that unfolds itself as the project proceeds, and also uncertainty that the starting and ending nodes of an activity fluctuate. This paper reformulates the concept of time to match to a dynamic scheduling through a non-deterministic approach. In particular, time can be regarded as an object in the holographic space, which models the dynamic aspects of time as a “mapped/represented” and “transformed/processed” temporal movement.

術前に診断しえた回腸原発T細胞性悪性リンパ腫の1例を経験した. 症例は64歳の男性.主訴は便秘, 右下腹部痛. 右下腹部痛の精査のため施行した注腸検査にて回盲部腫瘍を指摘された. 小腸造影透視にて回腸末端に潰瘍性病変を認め, 回腸末端と上行結腸の間に瘻孔を認めた. ガリウムシンチにて右下腹部に集積を認めた. 大腸内視鏡検査にて回腸末端に全周性の粗大結節と潰瘍形成が認められ, 生検にてT細胞性悪性リンパ腫と術前に診断された. 右半結腸切除術を施行した. 切除標本にて異型細胞は消化管壁内に限局していた. 術後に化学療法を4クール行った. 術後2年8か月間経過した現在再発は認めていない. 小腸原発のT細胞性悪性リンパ腫はまれで, 報告例の多くは, 穿孔あるいは腸閉塞などで発症し, 緊急手術後の病理検査にて診断されている. 瘻孔を形成した回腸原発T細胞性悪性リンパ腫と術前に診断しえた症例を文献的考察を加え報告する.

The ladder-Cu NMR spectrum of a structural disordered single crystal Sr14Cu24O41 (Sr14-B) under a magnetic field H~11 T gradually splits into two spectra with Curie-like broadening as T decreases from TSP~150 K. Short-range (SR) staggered polarization (SP) on the ladder planes, originating from single- hole localization, occurs. The separation of the Sr14-B spectrum DH deviates from the Curie-like T dependence below 20 K. This assures that spontaneous moments appear below TN~20 K in H~11 T

Development of a high-field NMR magnet has been underway at the Tsukuba Magnet Laboratory of the National Institute for Materials Science. The magnet succeeded in a persistent-mode operation at 21.17 T in December 1999. A 283-day long-term operation was carried out from October 2000 to August 2001. It included a persistent operation at 21.6 T (920 MHz) for 108 days. This was the highest field that the superconducting magnets have ever achieved in a persistent operation. Field decay was less than 2 Hz/h. Field homogeneity after correcting with superconducting shim coils were less than 0.1 ppm in a sample volume. These results confirmed that this magnet had been successfully developed as a high-resolution NMR magnet.

The critical currents of the innermost coil mainly limit the highest field of the present superconducting solenoids. For this reason, the insert coils in high-field solenoids are often wound with newly developed superconductors to increase their highest fields. This is a good demonstration of the high-field performance of the newly developed conductors. Design issues of high-field superconducting inserts are overviewed. Representative examples that have been carried out and are now in progress are introduced.

Magnetic force is one of the most promising tools to realize a virtual microgravity environment on Earth. It has been found that the growth of protein crystals might be affected by microgravity. The reason for this influence appears to be the suppression of the convectional flow. We are developing superconducting magnets to generate spatially uniform and high magnetic force fields that will suppress the convectional flow. We have completed a design for a superconducting magnet that is composed of Nb/sub 3/Sn and NbTi conductors. This magnet is designed to generate spatially uniform magnetic force fields up to 860 T/sup 2//m. The design was carried out using a method of nonlinear programming. The error of the axial component of the magnetic force fields is less than 1%, and the error of the radial ones is less than 2%. The central magnetic field of this magnet is 17 T at the operating current. We identified this magnet as Prototype II because the Prototype I, which had been constructed in 1998, was constructed with only NbTi conductors. Furthermore, it generates a magnetic force field of 240 T/sup 2//m and has a central magnetic field of 9 T, had been constructed in 1998. Prototype II will be cooled down below 4.5 K by two GM cryocoolers.

Persistent-mode operations of a cryocooler-cooled HTS magnet were carried out. The closed circuit of the magnet consisted of a Bi-2212 solenoid coil and a NbTi/CuNi persistent-current switch (PCS). Thermal conductance between the PCS and the cooling stage was designed not to heat up the coil. The temperature increase was maintained within 0.1 K during the normal state of the PCS. The transition times of the PCS between a superconducting and a normal state were sufficiently short for practical use. The magnet started a persistent-mode operation from an initial magnetic field of 2.1 T. Decay behaviors during persistent-mode operations were successfully observed over 90 hours. Except for the initial period, field decay was limited by resistance of the joint. A method to compensate the field decay was performed by installing a NbTi cylinder in the coil bore.

Although protein crystals of high integrity in a microgravity environment have been reported, the actual implementation of these experiments are very limited. The use of magnetic force is among the most promising methods of simulating the virtual microgravity environment on earth. We have been carrying out the development of superconducting magnets for generating uniform magnetic force fields since 1997. It was not clear at the beginning of this study what configuration of superconducting coils could generate high and uniform magnetic force fields most effectively. We used a nonlinear programming method to reach an optimized design. We constructed a superconducting magnet for generating uniform magnetic force fields, whose coil parameters were based on the optimization result. The superconducting magnet was wound with NbTi conductors and designed to generate 240T2/m of the magnetic force field and 9T of the central magnetic field. This magnetic force field can cancel 17% of the gravity force for pure water. The variation of the magnetic force field is less than 1.0% in the axial component and less than 2.0% in the radial component. The uniformity of the axial component was experimentally confirmed. The magnet has now been in operation for protein crystal growth experiments.

The magnetic lens, a new device for concentrating magnetic flux using the diamagnetism of superconductors, has been experimentally confirmed by employing HTS bulk. In this paper, a new magnetic lens made of NbTi/Cu rings is introduced. The rings, which have identical outer diameters and increasing inner diameters, were stacked to form a hollow cone. Each ring has a slit to suppress the circumference current. The slits were placed in the same position to form a leakage path. The lens was assembled in an existing cryostat system with a NbTi magnet, and the magnetic properties were measured. The concentrated magnetic flux density rose to 0.618 T when the background field reached 0.339 T at the tip of the lens. The concentration ratio was 1.82. These experimental results agree well with the numerical results.

We recently demonstrated that expression of ADP-ribosylation factor (ARF)-like 4c (Arl4c) induced by a combination of Wnt/β-catenin and epidermal growth factor/Ras signaling in normal epithelial cells grown in three-dimensional culture promotes cellular migration and proliferation, resulting in formation of tube-like structures, suggesting the involvement of Arl4c in epithelial morphogenesis. It is conceivable that there could be a common mechanism between epithelial morphogenesis and carcinogenesis. Therefore the current study was conducted to investigate whether Arl4c might be involved in tumorigenesis. Immunohistochemical analyses of tissue specimens obtained from colorectal and lung cancer patients revealed that Arl4c was not observed in non-tumor regions but was strongly expressed at high frequencies in tumor lesions. Inhibition of Wnt/β-catenin or Ras/mitogen-activated protein kinase signaling reduced Arl4c mRNA levels in HCT116 colorectal cancer cells and A549 lung cancer cells. Knockdown of Arl4c inhibited Rac activity and also prevented nuclear localization of yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) in these cancer cells. Arl4c-depleted cancer cells consistently showed decreased migration, invasion and proliferation capabilities both in vitro and in vivo. Furthermore, direct injection of Arl4c small interfering RNA (siRNA) into HCT116 cell-derived tumors (in vivo treatment with siRNA) inhibited tumor growth in immunodeficient mice. These results suggest that Arl4c is involved in tumorigenesis and might represent a novel therapeutic target for suppressing proliferation and invasion of colorectal and lung cancer cells.

Acid Mine Drainage (AMD) is one of the serious problems which are caused in the mining operation. The main factors which cause the problem are H2O and O2 and sulfide minerals such as iron pyrite. Sulfide minerals are usually contained in any type of crustal structure, and there is a possibility of generation of AMD in any area. The problem may impact on the ecosystem or people in the surrounding area since the acidic water is low-pH and usually contains high level of heavy metals. Therefore, it is important to prevent the problem in mining operation. A passive treatment is low-cost and easy to maintain for dealing with AMD problems. In a passive remediation, the study on behavior of AMD generation and elution behavior of heavy metals in a laboratory is necessary before introducing it in the mine site to construct it designed for the situation. Moreover, elution behavior may be changed by management of waste rock, as a practical matter, acidic water generates due to a rough treatment of waste rock in some mine sites. Therefore, in this research, the study on the waste rock was conducted for predicting a quality of acidic water by characterizing the rock and for elucidating effects of treatment of waste rock to elution behavior of heavy metals. This paper describes the results of laboratory experiments such as a column test and a sequence extraction for predicting elution behavior of heavy metals and an occurrence of acidic water, and treatment of waste rock for effective countermeasure for dealing with acidic water for a long term is discussed.

We found previously that N-(4-acetyl-1-piperazinyl)-p-fluorobenzamide monohydrate (FK960) facilitated hippocampal neurotransmission in the dentate gyrus of rat hippocampal slices. The present study was conducted to understand the mechanism underlying the facilitatory action of FK960. The facilitation was inhibited by H-89, an inhibitor of cAMP-dependent protein kinase (PKA), but it was not affected by cycloheximide, a protein synthesis blocker. In cultured rat hippocampal neurons, the drug had no effect on either spontaneous miniature excitatory postsynaptic currents or whole-cell membrane currents evoked by glutamate, kainate, or NMDA, suggesting that the facilitatory action of FK960 is not caused by increasing presynaptic transmitter release or excitatory postsynaptic conductances. FK960 inhibited responses of the glial glutamate transporter, GLT-1, expressed in Xenopus oocytes, and a similar effect was found with cultured rat astrocytes. The FK960 action was inhibited in the presence of H-89. The results of the present study thus suggest that FK960 facilitates hippocampal neurotransmission by inhibiting GLT-1 glial glutamate reuptake via a PKA pathway, thereby increasing synaptic glutamate concentrations.

A Nb/sub 3/Al superconductor based on jelly-rolled (JR) Nb/Al composites of high performance can be fabricated by rapid-heating and quenching of a wire of such composites with subsequent transformation-annealing to form the Nb/sub 3/Al phase (RHQT process). Since the conductor thereby is heated up to 2000/spl deg/C, far above the melting point of Cu, the Cu stabilizer needs to be externally incorporated by a mechanical-cladding method between quenching and annealing. Such an appropriate deformation promotes the transformation from a disordered bcc phase, and thereby enhances the critical current density J/sub c/. A solenoid coil was fabricated by a wind-and-react method: the Cu-clad conductor (1.61/sup w//spl times/0.71/sup t/ mm/sup 2/) with Al/sub 2/O/sub 3/ yarn insulation was wound into a coil (19.7/40.8/sup /spl phi///spl times/49.7/sup H/ mm), transformed at 800/spl deg/C, and impregnated with beeswax. The resultant coil, while carrying a current of 179 A at 2.1 K in a superconducting back-up field of 21.2 T, generated an additional 1.3 T. The total magnetic field of 22.5 T is the highest record ever for a metallic superconducting coil.

As a milestone in the 1-GHz NMR magnet project being carried out at the Tsukuba Magnet Laboratory, a 900-MHz class NMR magnet was successfully manufactured and operated in December 1999. The developed magnet is made of 15%Sn-bronze-processed (Nb,Ti)/sub 3/Sn, Ta-reinforced (Nb,Ti)/sub 3/Sn, and NbTi conductors. The room temperature bore of the cryostat is 54 mm is diameter. All the coils are cooled with pressurized superfluid helium. The magnet generated a field of 21.20 T in a driven mode and then operated in a persistent mode at 21.17 T corresponding to a proton NMR frequency of 902 MHz. The field may be raised to the range of 21.6 T (920 MHz) in the near future.

Magnetic force is one of the most promising tools to realize a virtual microgravity environment on earth. It has been found that the growth of protein crystals might be affected by microgravity owing to the suppression of convectional flow. We started the development of superconducting magnets for the generation of uniform and high magnetic force fields to suppress convectional flow, as it was not clear what configuration of superconducting coils could generate most effectively high magnetic force fields, while they maintain their uniformity. For this purpose, we used a nonlinear programming method. The results obtained clarified that a magnet whose inner coil is longer than the outer one can generate more uniform and higher magnetic force fields in a long sample space. A superconducting magnet generating a magnetic force field of 240 T/sup 2//m has already been constructed with NbTi conductors at the Tsukuba Magnet Laboratory. We have also completed the design of a superconducting magnet composed of Nb/sub 3/Sn and NbTi conductors to generate uniform magnetic force fields up to 882 T/sup 2//m.

A resistive insert magnet consisting of Bitter-type coils was fabricated, incorporated into the 400-mm bore of the superconducting outsert, and tested under a backup field of 14.2 T. This hybrid magnet generated a total field of 37.3 T in the center of a 32-mm room-temperature bore. At this magnetic field, the operating current of the resistive insert magnet was 33.25 kA at a voltage of 431 V. This insert magnet is divided into three coaxial coils. The bitter plates of the two inner coils are made of hard-worked Cu–Ag plates, and those of the outermost coil are made of GlidCop AL-25. The thickness of the plates used in the two inner coils was 0.84 mm, and the 0.2% proof stress in the direction parallel to the roll work was about 800 MPa at 375 K. This temperature is designed to be the maximum of the innermost coil at 37.3 T. Elongated cooling channels were punched in a staggered formation in these plates. The flow rate of the cooling water was 0.141 m 3 /s at the maximum field. Regular operation up to 35 T started from June 2000 at the Tsukuba Magnet Laboratory.

The Tsukuba Magnet Laboratory (TML) of the National Research Institute for Metals has been producing epoch-making achievements in the history of high-field magnets. Its hybrid magnet is in operation, providing users with fields up to 30 T in a 52-mm∅ room-temperature bore. In September 1999, the hybrid magnet generated a field of 37.3 T in a 32-mm∅ room-temperature bore, which was the world record of the steady-state fields at that time. The superconducting magnet system operating at TML succeeded in generating 23.4 T using two Bi-2212 insert coils. As a milestone in the 1 GHz NMR magnet project carried at TML, a 900 MHz NMR magnet was successfully manufactured and operated in a persistent mode. A challenging program in which different types of superconducting magnets are developed to meet specific requirements is in operation. One example is a magnet designed to generate uniform magnetic force fields defined as B grad B in a sample space. TML is now a user facility open to domestic and international users. Efforts will be continued to improve its high-field facilities by developing magnet technology as well as materials for high-field magnets.

The effect of storage at 0°C and 10°C on physical and biochemical parameters of 'Danshaku' tubers was monitored to provide baseline information on this cultivar's storage behavior. Sugar and starch level, weight loss, firmness, specific gravity, tissue color, fatty acid composition of phospholipicls, sprouting and respiration rate, starch content, particle size, and pasting properties were monitored. Sugar accumulation occurred in tubers stored at 0°C, while minimal sugar accumulation and severe sprouting and weight loss was observed for tubers at 10°C. Tubers stored at 10°C were consistently softer due to weight loss. No significant changes were observed in tissue color between storage treatments. Double bond index of tissue increased after 30 days at 0°C, indicating an adjustment to cold stress to increase tolerance. Sprouting occurred earlier in tubers stored at 10°C ; final respiration was also higher compared to tubers stored at 0°C. Starch content and particle size decreased during storage ; however, a greater reduction was observed at 0°C storage.

Studies on lunar base construction conducted by the writers' research group are summarized. A desirable lunar base design was first discussed by employing a systems engineering approach and by defining an evolutionary scenario, which emphasized resource utilization. Several lunar-base-related concepts were examined from the viewpoint of construction engineering including construction materials, structural design, and construction methods. The research also addressed resource utilization for the production of oxygen and construction materials. A commericial approach toward future lunar development is proposed.

A new quantitative reverse transcription-polymerase chain reaction (RT-PCR) method is described for analyzing the amount of GB virus-C (GBV-C)/hepatitis G virus (HGV) RNA in serum. This multicyclic RT-PCR (MRT-PCR) method used oligonucleotide primers deduced from the 3′ noncoding region (3′NCR) that is highly conserved among GBV-C/HGV isolates. Quantitation of GBV-C/HGV RNA using MRT-PCR ranged between 10 2 and 10 10 copies/ml when PCR cycle number was regulated at exponential amplification of the products. Competitive RT-PCR (CRT-PCR) was carried out with mutant RNA and sample that had been measured by MRT-PCR. Quantitation of GBV-C/HGV RNA using both methods agreed. MRT-PCR detected viral RNA in a single step PCR, and demonstrated a high degree of sensitivity that was equal to that of the RT-PCR procedure, which used nested primers deduced from the non-structural (NS) 3 region. The MRT-PCR method for quantitation of GBV-C/HGV RNA in serum may prove useful for diagnosis.

We have developed a novel superconducting joint method for Nb3Al conductors, which can be used for the innermost coil of a 1-GHz NMR magnet. First, we optimized the joint property; then, we prepared a closed circuit with an NbTi coil and a pair of Nb3Al-NbTi joints; finally, we determined the joint resistance by using the field decay of the persistent current. A joint resistance of 1.27 times 10-12 Omega was obtained, which is sufficiently low for high field NMR.

We report comprehensive Cu NMR studies on single crystals of ${\mathrm{Sr}}_{14\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{Cu}}_{24}{\mathrm{O}}_{41},$ which contain simple ${\mathrm{CuO}}_{2}$ chains and two-leg ${\mathrm{Cu}}_{2}{\mathrm{O}}_{3}$ ladders. From measurements of the ${}^{63}\mathrm{Cu}$ NMR shift, it is clear that the spin gap in the ladders decreases with isovalent Ca substitution from $\ensuremath{\Delta}=550\ifmmode\pm\else\textpm\fi{}30$ K for ${\mathrm{Sr}}_{14}{\mathrm{Cu}}_{24}{\mathrm{O}}_{41}$ (Sr14) to $350\ifmmode\pm\else\textpm\fi{}30$ K, $280\ifmmode\pm\else\textpm\fi{}30$ K, and $270\ifmmode\pm\else\textpm\fi{}30$ K for $x=6$ (Ca6), $x=9$ (Ca9), and $x=11.5$ (Ca11.5), respectively. The exponential decrease of the nuclear spin-lattice relaxation rate ${1/T}_{1}$ below \ensuremath{\sim}130 K is consistent with the presence of the spin gap in the spin excitation spectrum. In the $T$ range higher than $\ensuremath{\sim}200$ K, we observed the following dependences: ${1/T}_{1}=\mathrm{const}$ and the square of Gaussian spin-echo decay time, ${T}_{2G}^{2}\ensuremath{\propto}T$ which are consistent with the scaling theory for the $S=1/2$ one-dimensional (1D) Heisenberg model. The value of ${T}_{2G}{/T}_{1}\sqrt{T}$ is compatible with the theoretical prediction of an exchange constant along the leg ${J}_{\ensuremath{\parallel}}\ensuremath{\sim}1800$ K for Ca6 and ${J}_{\ensuremath{\parallel}}\ensuremath{\sim}1500$ K for Ca9 and Ca11.5. A notable finding is that the magnitude of the spin gap remains nearly constant and characteristics of novel 1D-like spin dynamics are maintained in the content varying from Ca9 to Ca11.5. On the other hand, the charge transport changes with increasing Ca content so that the more conductive Ca11.5 exhibits pressure-induced superconductivity exceeding 3.5 GPa. We have found that ${T}_{2G}^{2}$, which is proportional to the inverse spin correlation length ${\ensuremath{\xi}}^{\ensuremath{-}1}$, deviates from a linear $T$ dependence upon cooling and is described by $A+BT\mathrm{exp}(\ensuremath{-}\ensuremath{\Delta}/T)$, regardless of the Ca substitution. We point out that the value of ${T}_{2G}^{2}(T=0)=A$ is proportional to the finite value of ${\ensuremath{\xi}}_{0}^{\ensuremath{-}1}=\ensuremath{\Delta}{/c}_{1D},$ where ${c}_{1D}=(\ensuremath{\pi}{/2)J}_{\ensuremath{\parallel}}$ is the spin-wave velocity. From the result that the values of ${A}^{\ensuremath{-}1}\ensuremath{\sim}{\ensuremath{\xi}}_{\mathrm{eff}}$ for Ca6, Ca9, and Ca11.5 are significantly reduced compared to that for Sr14, it is suggested that ${\ensuremath{\xi}}_{\mathrm{eff}}$ is dominated at low $T$ by an average distance $d$ among mobile holes obeying the relation ${\ensuremath{\xi}}_{\mathrm{eff}}\ensuremath{\sim}d={\ensuremath{\xi}}_{h}.$ From an estimate of ${\ensuremath{\xi}}_{0}/a\ensuremath{\sim}$ 5.2 for Sr14, where $a$ is the Cu-Cu distance along the leg, ${\ensuremath{\xi}}_{h}/a$ is obtained as $\ensuremath{\sim}3.5$, 2.3, and 2.0, and hole content $x$ as $\ensuremath{\sim}0.14$, 0.22, and 0.25 per ${\mathrm{Cu}}_{2}{\mathrm{O}}_{3}$ ladder for Ca6, Ca9, and Ca11.5, respectively. These values were consistent with $x=$ 0.14, 0.2, and 0.22 for Ca6, Ca9, and Ca11 estimated from the optical conductivity experiment by Osafune et al. [Phys. Rev. Lett. 78, 1980 (1997)]. The ${\mathrm{Sr}}_{14\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{Cu}}_{24}{\mathrm{O}}_{41}$ compounds are thus hole-doped two-leg spin-ladder systems which reveal the metallic behavior dominated by the 1D-like spin dynamics at high $T$ and accompanied by the spin gap formation at low $T$. For Ca11.5, as the spin gap is formed upon cooling below $\ensuremath{\sim}180$ K, the resistivity increases in the direction perpendicular to the ladder, whereas the conductivity along the ladder remains metallic, followed by the localization of mobile holes in both directions below ${T}_{L}\ensuremath{\sim}60$ K. We point out that preformed pairs are confined in each ladder and localized below $\ensuremath{\sim}60$ K at an ambient pressure.

The survival ratios of yeast cells as a function of carbon beam penetration into a plastic block were evaluated at an initial energy of 135 MeV/amu. The cells were inserted into holes at several depths along the beam path. We estimated the inactivation ratios of both the haploid and the budding response of the haploid cell for the wild and the sensitive strain at stationary and growth phase. The ratios along the beam path were applicable as a method of beam adjustment in the planning of heavy ion therapy

We review systematic NMR studies on underdoped high- T c cuprates and two-leg spin-ladder systems, focusing on their spin gap and dynamics. The pressure-induced superconductivity was discovered in Sr 14− x Ca x Cu 24 O 41 comprising the quasi-one-dimensional S = ½ two-leg spin-ladder Cu 2 O 3 planes. Remarkably, the new parent cuprate is the Mott insulator with the spin gap in contrast to the antiferromagnetic (AF) insulator for the high- T c cuprates. From the Cu-NMR results in the ladder Cu 2 O 3 plane on single crystals Sr 14− x Ca x Cu 24 O 41 with x = 9 (hereafter denoted as Ca9) and x = 11.5 (Ca11.5), it is shown that the spin gap, Δ = 510K in the Sr14 is significantly reduced upon isovalent Ca substitution, but its magnitude remains nearly constant with Δ = 270 and 280K for the Ca9 and Ca11.5, respectively. In T range of T ⩾ Δ , the spin dynamics in carrier-doped two-leg spin-ladder systems are characterized by the behaviour similar to the S = ½ 1D Heisenberg system. By contrast, the transport property shares a common feature, i.e, due to the spin-gap opening the charge transport is confined in the 2D CuO 2 plane for underdoped high- T c , cuprates and in the quasi-1 D ladder for spin-ladder compounds.

The innermost coil of a new high-field NMR magnet such as a 1-GHz NMR magnet is designed by using a new superconductor. It is therefore important that a superconducting joint between the new superconductor and the NbTi conductor was developed. We have developed a new superconducting joint method for the Nb3Al conductor, which is expected to be used for the innermost coil of the 1-GHz NMR magnet. This joint method uses the Nb3Sn layer that is formed on the Nb matrix surface of the Nb3Al conductor. This Nb3Sn layer enables the soldering of the Nb3Al conductor; thus, it is possible to solder the Nb3Al conductor and NbTi conductor. The superconducting property of the Nb3Al-NbTi joint that is joined by the superconducting solder (for example, SnBiPb solder) showed good performance under a magnetic field of 0.1 T

An instantaneous blue shift of exciton absorption due to the optical Stark effect was observed in isolated semiconducting single-walled carbon nanotubes (SWNTs) by using a femtosecond (fs) pump-probe spectroscopy. From the analysis of time profiles of transient absorption changes, the photoinduced shift and the dipole moment of the exciton transition were evaluated as ~1.1 meV for the pump fluence of 34 µJ/cm2 and ~6 eA, respectively. Such a large dipole moment as well as ultrafast recovery of real carrier excitations suggests high potential of SWNTs for an ultrafast optical-switching material.

Magnetization measurements were performed on polycrystalline La 1.85 Sr 0.15 CuO 4 irradiated by 40 Ar ions with high energy of 13 GeV and 26 GeV up to 3.0 × 10 11 ions/cm 2 . An enhancement of magnetic irreversibility was observed. However the critical current density J c did hardly change after irradiation, suggesting a little effect on the magnetic flux-line pinning. On the other hand, a large increase in the lattice parameter c was found in the Ar ion irradiation at the energy as high as 13 and 26 GeV in comparison with that in the low-energy irradiation.

We measured intestinal permeability of mice by PIXE method. A mixture of a rubidium chloride solution and a manganese chloride solution was administered orally into mice. The blood was sampled successively after the administration, and the element contents in the blood were measured by PIXE method. The Rb content in the plasma of Rb + Mn administered group reaches maximum 5 min after the administration and decreases subsequently. The value in the whole blood of Rb + Mn administered group increases slightly for first 30 min after the administration and remarkably from 3 hrs. This increase continues for 48 hrs. That in control group is very little. Rb is probably transferred into plasma from intestinal mucosa at first, and subsequently moves into blood cells. The Mn content in control group is little. The values in the whole blood and the plasma of Rb + Mn administered group reach maximum 5 min after the administration and then decrease, and turn to decline to control level at 24 hrs. Mn is probably transferred into blood from intestinal mucosa throughout, and washed out more rapidly than Rb . The element contents of Rb and Mn in the plasma of Rb + Mn administered mice are found to increase to the peak level 5 min after the administration. Rb and Mn are useful as a tracer to study of intestinal disease with measurement by PIXE method. With this manner by PIXE method, intestinal permeability can be measured more briefly than existing methods. In order to assess intestinal permeability, we propose an indicator which is obtained by comparing the element amounts of Rb and/or Mn in blood sampled just after the administration.

Aim. To gain an insight into the effect of HCV replication-associated interference with the IFN system on hepatic mRNA expression involved in IFN production. Methods. Relative mRNA expression of TLR3/RIG-I signaling genes involved in IFN-β production was correlated with positive- and negative-strand HCV RNAs in pretreatment liver tissues responsive and nonresponsive to peginterferon and ribavirin for chronic hepatitis C genotype 1. Treatment response was analyzed for per protocol population at weeks 12 (n=45) and 24 (n=40) and at 24 weeks aftertreatment (n=38). Results. HCV replication had no relation to the expression of TLR3, RIG-I, TRIF, IPS-1, IRF3, and IFN-β mRNAs in responders. In striking contrast, positive- and/or negative-strand HCV showed positive correlations with TLR3, RIG-I, TRIF, IPS-1, and IRF3 mRNAs in week-12 nonresponders; with RIG-I, TRIF, IPS-1, and IRF3 mRNAs in week-24 nonresponders; and with TLR3, RIG-I, and IRF3 mRNAs in posttreatment nonresponders. Thus mRNA expression of TLR3/RIG-I signaling genes was increased in relation to viral replication in nonresponders. Conclusions. The findings in IFN nonresponders may imply a host feedback response to severe impairment of the IFN system associated with HCV replication.

The mechanism behind the spatiotemporal control of cancer cell dynamics and its possible association with cell proliferation has not been well established. By exploiting the intravital imaging technique, we found that cancer cell motility and invasive properties were closely associated with the cell cycle. In vivo inoculation of human colon cancer cells bearing fluorescence ubiquitination-based cell cycle indicator (Fucci) demonstrated an unexpected phenomenon: S/G2/M cells were more motile and invasive than G1 cells. Microarray analyses showed that Arhgap11a, an uncharacterized Rho GTPase-activating protein (RhoGAP), was expressed in a cell-cycle-dependent fashion. Expression of ARHGAP11A in cancer cells suppressed RhoA-dependent mechanisms, such as stress fiber formation and focal adhesion, which made the cells more prone to migrate. We also demonstrated that RhoA suppression by ARHGAP11A induced augmentation of relative Rac1 activity, leading to an increase in the invasive properties. RNAi-based inhibition of Arhgap11a reduced the invasion and in vivo expansion of cancers. Additionally, analysis of human specimens showed the significant up-regulation of Arhgap11a in colon cancers, which was correlated with clinical invasion status. The present study suggests that ARHGAP11A, a cell cycle-dependent RhoGAP, is a critical regulator of cancer cell mobility and is thus a promising therapeutic target in invasive cancers.