Field Induced Multiple Superconducting Phases in UTe_{2} along Hard Magnetic Axis.

The superconducting (SC) phase diagram in uranium ditelluride is explored under magnetic fields (H) along the hard magnetic b axis using a high-quality single crystal with T_{c}=2.1 K. Simultaneous electrical resistivity and ac magnetic susceptibility measurements discern low- and high-field SC (LFSC and HFSC, respectively) phases with contrasting field-angular dependence. Crystal quality increases the upper critical field of the LFSC phase, but the H^{*} of ∼15 T, at which the HFSC phase appears, is always the same through the various crystals. A phase boundary signature is also observed inside the LFSC phase near H^{*}, indicating an intermediate SC phase characterized by small flux pinning forces.

Thermal Hall Effect in a Phonon-Glass Ba_{3}CuSb_{2}O_{9}.

A distinct thermal Hall signal is observed in a quantum spin liquid candidate Ba_{3}CuSb_{2}O_{9}. The transverse thermal conductivity shows a power-law temperature dependence below 50 K, where a spin gap opens. We suggest that because of the very low longitudinal thermal conductivity and the thermal Hall signals, a phonon Hall effect is induced by strong phonon scattering of orphan Cu^{2+} spins formed in the random domains of the Cu^{2+}-Sb^{5+} dumbbells in Ba_{3}CuSb_{2}O_{9}.

Strong Suppression of the Spin Hall Effect in the Spin Glass State.

We have measured spin Hall effects in spin glass metals, CuMnBi alloys, with the spin absorption method in the lateral spin valve structure. Far above the spin glass temperature T(g) where the magnetic moments of Mn impurities are randomly frozen, the spin Hall angle of a CuMnBi ternary alloy is as large as that of a CuBi binary alloy. Surprisingly, however, it starts to decrease at about 4T(g) and becomes as little as 7 times smaller at 0.5T(g). A similar tendency was also observed in anomalous Hall effects in the ternary alloys. We propose an explanation in terms of a simple model considering the relative dynamics between the localized moment and the conduction electron spin.

Kosterlitz-Thouless-type transition in a charge ordered state of the layered organic conductor α-(BEDT-TTF)2I3.

The current-voltage characteristics in the charge order state of the two-dimensional organic conductor α-(BEDT-TTF)(2)I(3) exhibit power law behavior at low temperatures. The power law is understood in terms of the electric-field-dependent potential between electrons and holes, which are thermally excited from the charge order state. The power law exponent steeply changes from 1 to 3 in the range from 30 to 45 K with decreasing temperature, thereby suggesting the occurrence of a Kosterlitz-Thouless-type transition; many (few) unbound electron-hole pairs are thermally excited above (below) the transition. The effects of the finite size and interlayer coupling on the power law behavior are discussed.

Density-of-state oscillation of quasiparticle excitation in the spin density wave phase of (TMTSF)2ClO4.

Systematic measurements of the magnetocaloric effect, heat capacity, and magnetic torque under a high magnetic field up to 35 T are performed in the spin density wave (SDW) phase of a quasi-one-dimensional organic conductor (TMTSF)2ClO4. In the SDW phase above 26 T, where the quantum Hall effect is broken, rapid oscillations (ROs) in these thermodynamic quantities are observed, which provides clear evidence of the density-of-state (DOS) oscillation near the Fermi level. The resistance is semiconducting and the heat capacity divided by temperature is extrapolated to zero at 0 K in the SDW phase, showing that all the energy bands are gapped, and there is no DOS at the Fermi level. The results show that the ROs are ascribed to the DOS oscillation of the quasiparticle excitation.

Quasi-two-dimensional Fermi surfaces and coherent interlayer transport in KFe2As2.

We report the results of the angular-dependent magnetoresistance oscillations (AMROs), which can determine the shape of bulk Fermi surfaces (FSs) in quasi-two-dimensional (Q2D) systems, in a highly hole-doped Fe-based superconductor KFe2As2 with Tc ≈ 3.7 K. From the AMROs, we determined the two Q2D FSs with rounded-square cross sections, correspond to 12% and 17% of the first Brillouin zone. The rounded-squared shape of the FS cross section is also confirmed by the analyses of the interlayer transport under in-plane fields. From the obtained FS shape, we infer the character of the 3d orbitals that contribute to the FSs.

Development and application of 2.5 GPa-25 T high-pressure high-field electron spin resonance system using a cryogen-free superconducting magnet.

We have developed a high-pressure electron spin resonance probe and successfully installed into the world's highest-field cryogen-free superconducting magnet having a maximum central field of 24.6 T. The high pressure of 2.5 GPa is achieved by the specially designed piston-cylinder pressure cell using THz-wave-transparent components. In the first application of this high-pressure high-field ESR system, we observed that the orthogonal dimer spin system SrCu2(BO3)2 undergoes a quantum phase transition from the dimer singlet ground to the plaquette singlet ground states.

Magnetic field effects of photocarrier generation in bulk heterojunctions at low temperature.

We report an experimental investigation of the magnetic field effect (MFE) in polymer bulk heterojunction devices at temperatures below 10 K using photocarrier extraction by linearly increasing voltages. The examined devices were composed of an active layer of poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester. In the experiments, the delay time (td) dependence of the MFE was investigated in detail. For td < 80 µs, a positive MFE was observed in the field region B < 0.1 T and a negative MFE was observed for B > 0.2 T. For td > 8 ms, only a positive MFE proportional to B2 was observed. For the photocurrent pulse detected immediately after light irradiation, the MFE was negligibly small. In a high magnetic field of 15 T, a significant MFE exceeding 80% was observed at 1.8 K for td = 800 ms. We discuss the results based on a model of triplet-singlet (or singlet-triplet) conversion in the magnetic field and estimate the exchange integral for the charge-transfer exciton in this photovoltaic cell.

Roles of mitogen-activated protein kinase pathways for mediator release from human cultured mast cells.

Human cultured mast cells (HCMC) secrete histamine, sulfidoleukotrienes (LTs), and prostaglandin D(2) (PGD(2)), and produce a variety of cytokines after aggregation of high-affinity receptors for IgE (FcepsilonRI). With respect to the mitogen-activated protein kinase (MAPK) family, extracellular signal-regulated kinases (ERKs), c-Jun NH(2)-terminal kinases (JNKs), and p38 mitogen-activated protein kinase (p38 MAPK) are known. To investigate the roles of these kinase pathways for mediator release from human mast cells, we examined the participation of the activation of these kinases in mediator release, using 1,4-diamino-2, 3-dicyano-1,4-bis(2-aminophenylthio)butadiene (U0126), an ERK pathway inhibitor, and 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imid azo le (SB203580), a p38 MAPK pathway inhibitor. U0126 inhibited ERK activation, LT and PGD(2) release, and granulocyte macrophage-colony stimulating factor (GM-CSF) production after stimulation of HCMC. SB203580, on the other hand, potentiated JNK activation and GM-CSF production. The findings of the present study demonstrated that: (i) the release of arachidonic acid metabolites is mediated by the ERK pathway; (ii) GM-CSF production may be driven by both the ERK and JNK pathways; and (iii) the p38 MAPK pathway negatively regulates the JNK pathway. This suggests that MAPK pathways play important roles in mediator release from human mast cells.

Matrix metalloproteinase expression in cultured human gastric wall fibroblasts--interactions with Helicobacter pylori isolated from patients with ulcers.

BACKGROUND: Matrix metalloproteinases (MMPs), enzymes capable of degrading collagens and other extracellular matrix components, have been implicated in gastric ulcer formation. However, the effect on MMP expression of Helicobacter pylori, also implicated in these lesions, has not been studied to our knowledge. AIM: To seek links between H. pylori and MMP expression likely to affect gastric ulcer formation. After fibroblasts from human gastric wall were cocultured with H. pylori. concentrations of MMP-1 and -2 in the medium were determined by enzyme-linked immunosorbent assays. RESULTS: Whereas MMP-1 was not detected in media from fibroblasts or H. pylori culture alone, MMP-1 was detected in cocultures (P<0.01). Similar amounts of MMP-2 were detected in medium from fibroblasts cultured alone and with H. pylori. No MMP-2 production by H. pylori cultured alone was detected. CONCLUSIONS: MMP-1 appears to be important in gastric ulcer pathogenesis, and MMP-1 induction by H. pylori may impede gastric ulcer healing.

Suppression of natural killer activity in patients treated with cisplatin and methylprednisolone.

The achievable concentrations of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl-3-nitrosourea (ACNU), adriamycin, mitomycin C, vindesine, and epipodophyllotoxin suppressed the natural killer (NK) activity of human peripheral blood lymphocytes in vitro, whereas NK activity was not decreased 24 h after incubation with the maximum achievable concentration of cisplatin (cDDP). NK activity of patients treated with 80 mg per square meter of cDDP alone was not decreased for 3 weeks after cDDP administration. In contrast, NK activity of patients treated with the same dose of cDDP and methylprednisolone was significantly decreased 1 week after cDDP administration. It was concluded that methylprednisolone, used as an antiemetic agent, had an immunosuppressive effect.

Analysis of metastatic spread and growth of tumor cells in mice with depressed natural killer activity by anti-asialo GM1 antibody or anticancer agents.

The mechanism of artificial and spontaneous metastases of tumor was analyzed in B16 melanoma cells and C57BL/6 mice by using anti-asialo GM1 antibody and anticancer agents. Single administrations of 500 micrograms anti-asialo GM1 antibody resulted in significantly decreased NK activity in spleen cells of C57BL/6 mice, lasting 10 days from the day following administration. Treatment with anti-asialo GM1 antibody never decreased the function of T lymphocytes measured by blastogenesis with phytohemagglutinin or T cell growth factor. The tumoricidal functions of activated macrophages but not of resident macrophages were decreased by in vivo treatment with anti-asialo GM1 antibody. The anti-asialo GM1 antibody was evaluated in terms of the enhancing effect on pulmonary metastases with regard to the timing of administration. Treatment with anti-asialo GM1 antibody 1 day before or on the day of tumor inoculation resulted in a substantial increase in the number of artificial pulmonary metastases. In the experimental system of spontaneous metastases, anti-asialo GM1 antibody most effectively increased the number of pulmonary metastases when administered 1-2 weeks before the removal of primary tumor, when the tumor cells are thought to be released into blood circulation from the primary site. In addition, accelerated growth of transplanted tumors at the primary site was observed in mice treated with anti-asialo GM1 antibody. These results strongly suggest that anti-asialo GM1 antibody enhances the incidence of in vivo tumor metastases and the growth of transplanted tumor mainly by suppressing the function of NK cells. The maximum effective dose (MED) of mitomycin C or its derivative (M-83) suppressed NK activity significantly, and pretreatment with these anticancer agents enhanced the growth of the artificial pulmonary and liver metastases. In contrast, the MED of cDDP showed no effect on the NK activity or the numbers of pulmonary and liver metastases. These results indicate that the depression of NK activity induced by chemotherapy results in the promotion of metastatic disease. From these studies it can be concluded that NK cells have a key role in the control of metastases of malignant disease, and that support of NK activity is very important for the prevention of metastases.

Selective potentiation of IGE-dependent histamine release from rat peritoneal mast cells by stem cell factor.

Effect of stem cell factor on histamine release from rat peritoneal mast cells was studied. Although stem cell factor did not evoke histamine release by itself, it clearly potentiated histamine release from sensitized mast cells caused by antigen, anti-IgE and concanavalin A. However, stem cell factor did not affect histamine release caused by compound 48/80, calcium ionophore A23187 and substance P. Although maximum potentiation of antigen-induced histamine release by stem cell factor was accomplished after 1-10 minute-preincubation, potentiation was decline after a longer incubation period. Potentiation of histamine release by phosphatidylserine and non-mast cells in the rat peritoneal cavity was incubation time-dependent. Potentiation by stem cell factor was additive to that by phosphatidylserine or non-mast cells. These results indicate that stem cell factor selectively potentiates IgE-dependent histamine release from rat peritoneal mast cells, and suggest that the mechanism involved is distinct from that of phosphatidylserine or non-mast cells in the rat peritoneal cavity.

Laparoscopic wedge resection of gastric submucosal tumors.

Minimally invasive surgery has revolutionized the treatment of gastrointestinal tumors. Submucosal tumors (SMTs) of the stomach can be resected using laparoscopic techniques. Between 1993 and 1997, laparoscopic wedge resection was performed in 34 patients with an SMT of the stomach. The tumors ranged from 8 to 60 mm in diameter. All surgical margins were clear. The average operative time was 131 minutes. Most of the patients began eating on the first postoperative day and were discharged within 5 to 7 days. Histopathologic examination of the tumors showed gastrointestinal stromal tumor (n = 14), ectopic pancreas (n = 7), leiomyosarcoma (n = 4), schwannoma (n = 3), carcinoid (n = 2), leiomyoma (n = 2), an inflammatory lesion caused by parasites (n = 1), and cyst (n = 1). No recurrences were observed over the 5-year follow-up period. A solid SMT of the stomach larger than 20 mm in diameter can be treated using laparoscopic wedge resection.

[Double-blind comparison of L-keflex and cephalexin (Keflex) in dental infections (author's transl)].

In order to evaluate efficacy and safety of L-Keflex (granule form of sustained release cephalexin), a double blind study comparing it with Keflex (capsule of regular cephalexin) was conducted in dental infections. Evaluable cases in adults for efficacy of the drugs were 196 consisting of 97 for L-Keflex and 99 for Keflex. Those in children were 19 (8 for L-Keflex and 11 for Keflex). There were no significant differences in background of the patients and severity of the diseases between both groups (L-Keflex and Keflex groups). The daily doses used in both groups were 1,000 mg in adults and 500 mg in children, respectively. The dose was given in two divided doses for L-Keflex group and in four divided doses for Keflex group. Following are evaluation by the committee members for the study: Adults 1. Clinical response rate at final therapy day was 93.8% in L-Keflex group and 92.9% in Keflex group, showing no significant difference between both groups. 2. No significant difference in severity of subjective and objective symptoms between both groups was observed at each therapy day. 3. Side effects were found in 6.7% of 105 patients receiving L-Keflex and in 5.6% of 107 patients with Keflex, and there was no significant difference between both groups. As the side effects, gastrointestinal symptoms, rash and itching were observed, but no any other side effects were found in both groups. Children 1. As shown in the above, number of the cases enough to evaluate statistically was not obtained, but all of both groups clinically responded to the drugs. 2. As for side effects diarrhea was observed in only one patient of Keflex group consisting of 12 patients. In the patient, however, discontinuation of the drug was not required and the side effect disappeared during the therapy. From the above results, L-Keflex (granule) is judged to have more convenience than Keflex (capsule) in that (1) it can be administered with b.i.d. regimen and (2) it can be easily taken in dental patients such as patients having difficulty in opening mouth of swallowing pain.

[Analysis of the mechanism of cancer metastasis by using anticancer agents].

For the analysis of the mechanism of cancer metastasis, effects of anticancer agents on the NK activity of spleen cells and on the artificial metastasis of B-16 melanoma cells were comparatively studied. The inhibitory effect of these anticancer agents on the growth of B-16 melanoma inoculated to foot pad of C57/BL6 mice was also examined. The growth of B-16 melanoma was inhibited by intravenous administration of 6 mg/kg of MMC, 18 mg/kg of KW-2083 and 5 mg/kg of CDDP, but not of 6 mg/kg of KW-2083. The NK activities in spleen cells of C57/BL6 mice administered with 6 mg/kg of MMC and 18 mg/kg of KW-2083 were decreased, but they were not decreased in mice administered with 6 mg/kg of KW 2083 and 5 mg/kg of CDDP. Significant increases in the number of artificial pulmonary and liver metastasis were observed in mice administered with 6 mg/kg of MMC and 18 mg/kg of KW-2083. It is suggested that the depression of NK activity induced by anticancer agents results in the promotion of metastatic disease.

[Effect of CDDP administration on NK activity of human peripheral lymphocytes and its modification by corticosteroid as anti-emetic agent].

The effect of cDDP (cis-diamminedichloroplatinum) on NK (natural killer) activity of peripheral blood lymphocytes in 12 patients (7 primary lung cancer, 3 metastatic pulmonary tumor and 2 malignant mediastinal tumor) was examined with emphasis on the combination of corticosteroid. To all patients, 80 mg/m2 of CDDP was administered intravenously every 3 weeks. Four patients were treated with CDDP alone, and 8 patients received 375 mg of methylprednisolone on the same day of CDDP administration and 125 mg on each of following consecutive 5 days respectively. 1) NK activity was not suppressed for 3 weeks after CDDP administration, in the group of 4 patients without receiving corticosteroid. 2) Significant NK suppression was found 1 week after CDDP administration, and recovered 2 weeks later, in the group of 8 patients who were treated for their emesis by corticosteroid. It can be concluded that 80 mg/m2 of CDDP does not reduce NK activity at all. However, the additional administration of corticosteroid strongly inhibited NK activity. Therefore, one should be very careful when combines the corticosteroid in order to relieve emesis induced by CDDP treatment, even if it has some antiemetic effect.

Cleft lip in oculodentodigital dysplasia suggests novel roles for connexin43.

Oculodentodigital Dysplasia (ODDD) is a rare syndrome involving anomalies in eye, tooth, and digit formation, caused by mutations in CX43/GJA1. In addition to classic dental features, ODDD includes oral and craniofacial accessory symptoms such as characteristic facial appearance and cleft palate. However, there have been no reports of ODDD accompanied by cleft lip. Herein we report, for the first time, a male, sporadic, Asian proband presenting bilateral cleft lip. By direct sequence analysis, our proband was diagnosed as having ODDD with a heterozygous mutation, codon 142 G>A in GJA1 and CX43E48K. We excluded the possibility of pathogenic mutations in B3GALTL, BMP4, TFAP2A, PVRL1, IRF6, and MSX1. To address how CX43/GJA1 is related to cleft lip, we performed immunohistochemistry using mouse and human mid-facial tissue. CX43 expression was detected in the nasal compartment and nasal and maxillary processes at murine developmental stage E12.5. Furthermore, CX43 expression was found in the epithelial tissue inside the human subepithelial cleft lip that completes epithelial fusion. Therefore, we suggest that CX43/GJA1 is involved in lip formation. Our case report of ODDD with a bilateral cleft lip suggests that CX43/GJA1 might be a novel candidate gene for syndromic cleft lip.