A scheduling and diagnostic system for scientific satellite GEOTAIL using expert system

The Intelligent Satellite Control Software (ISACS) for the geoMagnetic tail observation satellite named GEOTAIL (launched in July 1992) has been successfully developed. ISACS has made it possible by applying Artificial Intelligence (AI) technology including an expert system to autonomously generate a tracking schedule, which originally used to be conducted manually. Using ISACS, a satellite operator can generate a maximum four day period of stored command stream autonomously and can easily confirm its safety. The ISACS system has another function -- to diagnose satellite troubles and to suggest necessary remedies. The workload of satellite operators has drastically been reduced since ISACS has been introduced into the operations of GEOTAIL

Hidden non-Fermi liquid behavior due to crystal field quartet

We study a realistic Kondo model for crystal field quartet ground states having magnetic and non-magnetic (quadrupolar) exchange couplings with conduction electrons, using the numerical renormalization group method. We focus on a local effect dependent on singlet excited states coupled to the quartet, which reduces the non-magnetic coupling significantly and drives non-Fermi liquid behavior observed in the calculated quadrupolar susceptibility. A crossover from the non-Fermi liquid state to the Fermi liquid state is characterized by a small energy scale very sensitive to the non-magnetic coupling. On the other hand, the Kondo temperature observed in the magnetic susceptibility is less sensitive. The different crystal-field dependence of the two exchange couplings may be related to the different $x$ dependence of quadrupolar and magnetic ordering temperatures in Ce$_x$La$_{1-x}$B$_6$.Comment: 7 pages, 5 EPS figures, REVTe

Off Equilibrium Study of the Fluctuation-Dissipation Relation in the Easy-Axis Heisenberg Antiferromagnet on the Kagome Lattice

Violation of the fluctuation-dissipation theorem (FDT) in a frustrated Heisenberg model on the Kagome lattice is investigated using Monte Carlo simulations. The model exhibits glassy behaviour at low temperatures accompanied by very slow dynamics. Both the spin-spin autocorrelation function and the response to an external magnetic field are studied. Clear evidence of a constant value of the fluctuation dissipation ratio and long range memory effects are observed for the first time in this model. The breakdown of the FDT in the glassy phase follows the predictions of the mean field theory for spin glasses with one-step replica symmetry breaking.Comment: 4 pages, 4 figure

A Theory of Anisotropic Semiconductor of Heavy Fermions

It is demonstrated that a {\veck}-dependence of the hybridization matrix element between $f$- and conduction electrons can give rise to an anisotropic hybridization gap of heavy fermions if the filling of electrons corresponds to that of the band insulator. The most interesting case occurs when the hybridization vanishes along some symmetry axis of the crystal reflecting a particular symmetry of the crystal field. The results of a model calculation are consistent with wide range of anomalous properties observed in CeNiSn and its isostructural compounds, the anisotropic semiconductor of heavy fermions. In particular, highly sensitive effect of impurity scattering on the residual density of states for zero energy excitation and the anisotropic temperature dependence of the resistivity are well explained. It is also discussed that a weak semimetallic behavior arises through the weak \veck-dependence of the $f$-electron self-energy \Sigma_{f}(\veck,0).Comment: 21 pages, LaTeX (JPSJ style file) and 13 postscript figures, To appear in J. Phys. Soc. Jp

Resistivity, Hall effect and Shubnikov-de Haas oscillations in CeNiSn

The resistivity and Hall effect in CeNiSn are measured at temperatures down to 35 mK and in magnetic fields up to 20 T with the current applied along the {\it b} axis. The resistivity at zero field exhibits quadratic temperature dependence below $\sim$0.16 K with a huge coefficient of the $T^2$ term (54 $\mu$$\Omega$cm/K$^2$). The resistivity as a function of field shows an anomalous maximum and dip, the positions of which vary with field directions. Shubnikov-de Haas (SdH) oscillations with a frequency {\it F} of $\sim$100 T are observed for a wide range of field directions in the {\it ac} and {\it bc} planes, and the quasiparticle mass is determined to be $\sim$10-20 {\it m}$_e$. The carrier density is estimated to be $\sim10^{-3}$ electron/Ce. In a narrow range of field directions in the {\it ac} plane, where the magnetoresistance-dip anomaly manifests itself clearer than in other field directions, a higher-frequency ($F=300\sim400\text{T}$) SdH oscillation is found at high fields above the anomaly. This observation is discussed in terms of possible field-induced changes in the electronic structure.Comment: 15 pages, 5 figures, to appear in Phys. Rev. B (15 Sept. 2002 issue

Universal scaling in the dynamical conductivity of heavy fermion Ce and Yb compounds

Dynamical conductivity spectra s(w) have been measured for a diverse range of heavy-fermion (HF) Ce and Yb compounds. A characteristic excitation peak has been observed in the mid-infrared region of s(w) for all the compounds, and has been analyzed in terms of a simple model based on conduction (c)-f electron hybridized band. A universal scaling is found between the observed peak energies and the estimated c-f hybridization strengths of these HF compounds. This scaling demonstrates that the model of c-f hybridized band can generally and quantitatively describe the charge excitation spectra of a wide range of HF compounds.Comment: 5 pages, 1 table, 3 figures, to appear in J. Phys. Soc. Jpn. 76 (2007

Microrna-9-5p-CDX2 axis: A useful prognostic biomarker for patients with stage II/III colorectal cancer

A lack of caudal-type homeobox transcription factor 2 (CDX2) protein expression has been proposed as a prognostic biomarker for colorectal cancer (CRC). However, the relationship between CDX2 levels and the survival of patients with stage II/III CRC along with the relationship between microRNAs (miRs) and CDX2 expression are unclear. Tissue samples were collected from patients with stage II/III CRC surgically treated at Kyoto University Hospital. CDX2 expression was semi-quantitatively evaluated by immunohistochemistry (IHC). The prognostic impacts of CDX2 expression on overall survival (OS) and relapse-free survival (RFS) were evaluated by multivariable statistical analysis. The expression of miRs regulating CDX2 expression and their prognostic impacts were analyzed using The Cancer Genome Atlas Program for CRC (TCGA-CRC). Eleven of 174 CRC tissues lacked CDX2 expression. The five-year OS and RFS rates of patients with CDX2-negative CRC were significantly lower than those of CDX2-positive patients. Multivariate analysis of clinicopathological features revealed that CDX2-negative status is an independent marker of poor prognosis in stage II/III CRC. miR-9-5p was shown to regulate CDX2 expression. TCGA-CRC analysis showed that high miR-9-5p expression was significantly associated with poor patient prognosis in stage II/III CRC. In conclusion, CDX2, the post-transcriptional target of microRNA-9-5p, is a useful prognostic biomarker in patients with stage II/III CRC

XRCC1 Arg194Trp polymorphism, risk of nonmelanoma skin cancer and extramammary Paget’s disease in a Japanese population

The X-ray repair cross-complementing groups 1 gene plays an important role in base excision repair. At least three common single nucleotide polymorphisms frequently occur in this gene (Arg399Gln, Arg194Trp and Arg280His). Recent studies reported that these polymorphisms were associated with not only risk of visceral malignancy but also that of skin cancer such as basal cell carcinoma and squamous cell carcinoma, whereas the results of previous study vary among races. In this case–control study, we investigated whether these single nucleotide polymorphisms were associated with the risk of skin cancer in a Japanese population. The study population was composed of 197 patients with skin cancer (27 actinic keratoses, 47 basal cell carcinomas, 27 squamous cell carcinomas, 29 Bowen’s diseases, 46 malignant melanomas and 21 extramammary Paget’s diseases) and 93 control subjects. We genotyped two single nucleotide polymorphisms (Arg194Trp and Arg399Gln) using polymerase chain reaction-restriction fragments length polymorphism analysis. We found a significantly increased risk for basal cell carcinoma, squamous cell carcinoma and extramammary Paget’s disease associated with Arg194Trp [adjusted odds ratio (AOR) = 2.347, 3.587, 3.741, 95 % confidence interval (CI) 1.02–5.39, 1.19–10.8, 1.15–12.2, respectively]. We also found a significantly decreased risk for basal cell carcinoma associated with Gln399Gln (AOR = 0.259, 95 % CI 0.07–0.96). Our data suggest that the Arg194Trp polymorphism could be associated with nonmelanoma skin cancer and extramammary Paget’s disease risk in a Japanese population

Cardioprotective Effect of Nicorandil, a Mitochondrial ATP-Sensitive Potassium Channel Opener, Prolongs Survival in HSPB5 R120G Transgenic Mice

BACKGROUND: Transgenic (TG) mice with overexpression of an arg120gly (R120G) missense mutation in HSPB5 display desmin-related cardiomyopathy, which is characterized by formation of aggresomes. It is also known that progressive mitochondrial abnormalities and apoptotic cell death occur in the hearts of R120G TG mice. The role of mitochondrial dysfunction and apoptosis in disease progression, however, remains uncertain. METHODS AND RESULTS: Mitochondrial abnormalities and apoptotic cell death induced by overexpression of HSPB5 R120G were analyzed in neonatal rat cardiomyocytes. Overexpression of mutant HSPB5 led to development of aggresomes with a concomitant reduction in cell viability in the myocytes. Overexpression of mutant HSPB5 induced a reduction in the cytochrome c level in the mitochondrial fraction and a corresponding increase in the cytoplasmic fraction in the myocytes. Down-regulation of BCL2 and up-regulation of BAX were detected in the myocytes expressing the mutant HSPB5. Concomitant with mitochondrial abnormality, the activation of caspase-3 and increased apoptotic cell death was observed. Cell viability was dose-dependently recovered in myocytes overexpressing HSPB5 R120G by treatment with nicorandil a mitochondrial ATP-sensitive potassium channel opener. Nicorandil treatment also inhibited the increase in BAX, the decrease in BCL2, activation of caspase-3 and apoptotic cell death by mutant HSPB5. To confirm the results of the in-vitro study, we analyzed the effect of nicorandil in HSPB5 R120G TG mice. Nicorandil treatment appeared to reduce mitochondrial impairment and apoptotic cell death and prolonged survival in HSPB5 R120G TG mice. CONCLUSIONS: Nicorandil may prolong survival in HSPB5 R120G TG mice by protecting against mitochondrial impairments