Giant magneto-optical responses in magnetic Weyl semimetal Co3Sn2S2.

The Weyl semimetal (WSM), which hosts pairs of Weyl points and accompanying Berry curvature in momentum space near Fermi level, is expected to exhibit novel electromagnetic phenomena. Although the large optical/electronic responses such as nonlinear optical effects and intrinsic anomalous Hall effect (AHE) have recently been demonstrated indeed, the conclusive evidence for their topological origins has remained elusive. Here, we report the gigantic magneto-optical (MO) response arising from the topological electronic structure with intense Berry curvature in magnetic WSM Co3Sn2S2. The low-energy MO spectroscopy and the first-principles calculation reveal that the interband transitions on the nodal rings connected to the Weyl points show the resonance of the optical Hall conductivity and give rise to the giant intrinsic AHE in dc limit. The terahertz Faraday and infrared Kerr rotations are found to be remarkably enhanced by these resonances with topological electronic structures, demonstrating the novel low-energy optical response inherent to the magnetic WSM.

Topological Kagome Magnet Co3Sn2S2 Thin Flakes with High Electron Mobility and Large Anomalous Hall Effect.

Magnetic Weyl semimetals attract considerable interest not only for their topological quantum phenomena but also as an emerging materials class for realizing quantum anomalous Hall effect in the two-dimensional limit. A shandite compound Co3Sn2S2 with layered kagome-lattices is one such material, where vigorous efforts have been devoted to synthesize the two-dimensional crystal. Here, we report a synthesis of Co3Sn2S2 thin flakes with a thickness of 250 nm by chemical vapor transport method. We find that this facile bottom-up approach allows the formation of large-sized Co3Sn2S2 thin flakes of high-quality, where we identify the largest electron mobility (∼2600 cm2 V-1 s-1) among magnetic topological semimetals, as well as the large anomalous Hall conductivity (∼1400 Ω-1 cm-1) and anomalous Hall angle (∼32%) arising from the Berry curvature. Our study provides a viable platform for studying high-quality thin flakes of magnetic Weyl semimetal and stimulate further research on unexplored topological phenomena in the two-dimensional limit.

Topological transitions among skyrmion- and hedgehog-lattice states in cubic chiral magnets.

Manipulating topological spin textures is a key for exploring unprecedented emergent electromagnetic phenomena. Whereas switching control of magnetic skyrmions, e.g., the transitions between a skyrmion-lattice phase and conventional magnetic orders, is intensively studied towards development of future memory device concepts, transitions among spin textures with different topological orders remain largely unexplored. Here we develop a series of chiral magnets MnSi1-xGex, serving as a platform for transitions among skyrmion- and hedgehog-lattice states. By neutron scattering, Lorentz transmission electron microscopy and high-field transport measurements, we observe three different topological spin textures with variation of the lattice constant controlled by Si/Ge substitution: two-dimensional skyrmion lattice in x = 0-0.25 and two distinct three-dimensional hedgehog lattices in x = 0.3-0.6 and x = 0.7-1. The emergence of various topological spin states in the chemical-pressure-controlled materials suggests a new route for direct manipulation of the spin-texture topology by facile mechanical methods.

Large magneto-thermopower in MnGe with topological spin texture.

Quantum states characterized by nontrivial topology produce interesting electrodynamics and versatile electronic functionalities. One source for such remarkable phenomena is emergent electromagnetic field, which is the outcome of interplay between topological spin structures with scalar spin chirality and conduction electrons. However, it has scarcely been exploited for emergent function related to heat-electricity conversion. Here we report an unusually enhanced thermopower by application of magnetic field in MnGe hosting topological spin textures. By considering all conceivable origins through quantitative investigations of electronic structures and properties, a possible origin of large magneto-thermopower is assigned to the strong energy dependence of charge-transport lifetime caused by unconventional carrier scattering via the dynamics of emergent magnetic field. Furthermore, high-magnetic-field measurements corroborate the presence of residual magnetic fluctuations even in the nominally ferromagnetic region, leading to a subsisting behavior of field-enhanced thermopower. The present finding may pave a way for thermoelectric function of topological magnets.

[A Case of central venous catheter-related infection with Malassezia sympodialis].

We report a 63-year-old male with central venous catheter-related infection caused by Malassezia sympodialis after total gastrectomy for a gastric cancer. He had fever and his leukocyte counts and C-reactive protein were elevated 14 days after his operation. After his central venous hyperalimentation catheter was removed, the inflammatory signs immediately disappeared, suggesting an intravenous catheter-related infection. A yeast-like fungus was cultured in brain-heart infection semi-solid agar ten days later, and was diagnosed morphologically as Malassezia sp. This strain was identified as M. sympodialis by Tween assimilation test and was confirmed by whole-sequence of internal transcribed spacer 1 regions (ITS1). This is the first report of catheter-related infection caused by M. sympodialis. This strain grew and was subcultured on CHROMagar Candida, potato dextrose agar and Sabouraud agar. There have been no reports of such a lipid-independent Malassezia sp. except for M. pachydermatis. The mechanism of lipid independence of this strain is undetermined and future work is needed. Malassezia sp. is receiving increased attention as an etiologic pathogen of catheter-related fungemia in clinical microbiology laboratories and infectious disease sections.

Cold crucible levitation melting of biomedical Ti-30 wt%Ta alloy.

Recently, titanium-tantalum alloys have been studied as implant materials for dental and orthopedic surgery. However, titanium and tantalum are difficult to mix by common arc melting and induction melting, because of their high melting point and the marked difference between their densities (Ti: 1,680 degrees C, 4.5 g/cm3, Ta: 2,990 degrees C, 16.6 g/cm3). Thus, the Cold Crucible Levitation Melting (CCLM) method was chosen to produce a Ti-30 wt%Ta binary alloy in the present study. The CCLM furnace, with 1 kg capacity, consisted of a water-cooled crucible comprising oxygen-free high purity copper segments and coils wrapped around the crucible and connected to a frequency inverter power supply. A qualified ingot of 1.0 kg of Ti-30 wt%Ta alloy was obtained. The ingot was characterized from the surface quality, chemical composition distribution and microstructure, and finally the melting process was discussed.

Preparation and compressive strength of alpha-tricalcium phosphate/gelatin gel composite cement.

A novel alpha-tricalcium phosphate (TCP) and gelatin gel composite cement was prepared, and the effects of gelatin content, liquid/powder ratio, setting time, and additives (rod-like hydroxyapatite and CaTiO3 particles) on the microstructure and compressive strength of the setting product were investigated. Addition of gelatin gel to alpha-TCP cement resulted in the formation of a porous solid possessing pores of 20-100 microm in diameter whose pore diameter increased with increasing gelatin gel content. The compressive strength of alpha-TCP cement after 1 week increased from 9.0 to 14.1 MPa with increasing gelatin gel content up to 5 wt % and thereafter decreased. The compressive strength of the cement containing 5 wt % gelatin gel increased with time up to 35 MPa after 1 month whereas without gelatin gel it was approximately 20 MPa. Dispersion of 5 wt % of rod-like hydroxyapatite and CaTiO3 powders with alpha-TCP cement containing 5 wt % gelatin gel increased the compressive strength after 1 week from 14.1 to 31.3 and 34.8 MPa, respectively.

Coating of hydroxyapatite on various substrates via hydrothermal reactions of Ca(edta)2- and phosphate.

Hydroxyapatite was coated on various substrates such as 12 mol % ceria-doped tetragonal zirconia (12Ce-TZP), 3 mol % yttria-doped tetragonal zirconia (3Y-TZP), alumina, monetite coated titanium (Ti/CaHPO4) and calcium titanate coated titanium (Ti/CaTiO3) via hydrothermal reactions of Ca(edta)2- and 0.05 M NaH2PO4 at initial pH 6 and 160-200 degrees C for 0.5-6 h. Rod-like particles of hydroxyapatite precipitated to form film on the substrates above 160 degrees C. The morphology of the film changed significantly depending on the characteristics of substrate, i.e. hydroxyapatite entirely coated the surfaces of 12Ce-TZP, Ti/CaHPO4 and Ti/CaTiO3 plates, but sparsely deposited on 3Y-TZP and Al2O3 plates. Film thickness increased with time (ca. 20 and 90 microm on 12Ce-TZP plates for 0.5 and 6 h, respectively, at pH 6 and 200 degrees C). The adhesive strength of the film for the substrate was in the order, 12Ce-TZP/hydroxyapatite(28 MPa) > Ti/CaTiO3/hydroxyapatite (22 MPa) > Ti/CaHPO4/hydroxyapatite (9 MPa).

Lightning injury as a blast injury of skull, brain, and visceral lesions: clinical and experimental evidences.

The present study attempts to better understand the mechanism of injuries associated with direct lightning strikes. We reviewed the records of 256 individuals struck by lightning between 1965 and 1999, including 56 people who were killed. Basal skull fracture, intracranial haemorrhage, pulmonary haemorrhage, or solid organ rupture was suspected in three men who died. Generally these lesions have been attributed to current flow or falling after being struck. However, examination of surface injuries sustained suggested that the true cause was concussion secondary to blast injury resulting from vaporization of water on the body surface by a surface flashover spark. To investigate this hypothesis, an experimental model of a lightning strike was created in the rat. Saline-soaked blotting paper was used to simulate wet clothing or skin, and an artificial lightning impulse was applied. The resultant lesions were consistent with our hypothesis that the blast was reinforced by the concussive effect of water vaporization. The concordance between the clinical and experimental evidence argues strongly for blast injury as an important source of morbidity and mortality in lightning strikes.

Lineage-specific regulation of the murine RAG-2 promoter: GATA-3 in T cells and Pax-5 in B cells.

Recombination activating gene-1 (RAG-1) and RAG-2 are expressed in lymphoid cells undergoing the antigen receptor gene rearrangement. A study of the regulation of the mouse RAG-2 promoter showed that the lymphocyte-specific promoter activity is conferred 80 nucleotide (nt) upstream of RAG-2. Using an electrophoretic mobility shift assay, it was shown that a B-cell-specific transcription protein, Pax-5, and a T-cell-specific transcription protein, GATA-3, bind to the -80 to -17 nt region in B cells and T cells, respectively. Mutation of the RAG-2 promoter for Pax-5- and GATA-3-binding sites results in the reduction of promoter activity in B cells and T cells. These results indicate that distinct DNA binding proteins, Pax-5 and GATA-3, may regulate the murine RAG-2 promoter in B and T lineage cells, respectively. (Blood. 2000;95:3845-3852)

Lactate dehydrogenase A-dependent surface expression of immature thymocyte antigen-1: an implication for a novel trafficking function of lactate dehydrogenase-A during T cell development.

A possible involvement of lactate dehydrogenase A (LDHA) in the translocation of a thymic differentiation antigen, immature thymocyte antigen-1 (IMT-1), from cytoplasm to cell surface membrane during thymocyte differentiation is described. Transfection of cDNA for LDHA, but not LDHB, into EL4 cells, which expressed IMT-1 in the cytoplasm but not on the cell surface, induced the expression of IMT-1 on the cell surface. This translocation process seemed to be dependent on the translation of LDHA cDNA in EL4 cells, as well as the native structure of LDHA composing of coenzyme binding domain, catalysis domain, and subunit contact domain. Immunoprecipitation analysis revealed that LDHA could be co-precipitated with IMT-1 from the cell surface of EL4 cells that had been transfected with LDHA cDNA, suggesting that some of LDHA is associated with cell surface IMT-1 on the transfectants. Flow cytometry analysis of thymocyte subpopulations showed that some thymocytes at the CD4(-)CD8(-) double negative stage express both IMT-1 and LDHA on their surface. These data indicate that LDHA, in addition to its function in the metabolism in the glycolytic pathway, may have a novel function in the expression of a cell surface antigen during T cell development.

Correlation between magnetic resonance imaging and histopathology of an amputated forearm after an electrical injury.

A 53-year-old man sustained a 50 Hz, 60 kV electrical injury. The current flowed between his right hand and both feet. There was necrosis of the distal portion of the right forearm, and the fourth and fifth toes on the right foot. The skin on the amputated right upper extremity appeared normal except for an ulcer in the antecubital fossa and some blister scars. However, most of the muscles of the arm at the elbow were necrosed and partially replaced by fatty tissue or fibrosis. These necrotic areas corresponded to minimally increased signal intensities on T1-weighted MRI, and high signal intensities on T2-weighted images. MRI may be employed to predict amputation level after electrical injury.

Coating of CaTiO3 on titanium substrates by hydrothermal reactions using calcium-ethylene diamine tetra acetic acid chelate.

Titanium plates were treated in [Ti(O2)EDTA]2- -Ca(EDTA)2- mixed solutions and/or Ca(EDTA)2- solutions (where EDTA is ethylene diamine tetra acetic acid) at pH 9-13 and 150-250 degrees C for 0.5-12 h. The film, about 50 microm thick, and consisting of mixtures of CaTiO3 and TiO2 was formed in 0.01 M [Ti(O2)EDTA]2- - 0.01 M Ca(EDTA)2- mixed solution at pH 13 and 250 degrees C for 6 h. The film consisted of large icosahedral and hexagonal particles, of about 10 microm diameter, and small aggregated particles, of about 1 microm diameter. On the other hand, the film, about 20 microm thick, consisted of hexagonal plate-like CaTiO3 particles, of about 1 microm diameter, was formed in 0.01 M Ca(EDTA)2- solution at pH 13 and 250 degrees C for 6 h. The thickness of both films increased with time, where the film formation rate in 0.01 M [Ti(O2)EDTA]2- - 0.01 M Ca(EDTA)2- mixed solution was much faster. The CaTiO3 film formed on the surface of titanium promoted the precipitation of hydroxyapatite on the substrate by the hydrothermal reactions in Ca(EDTA)2- -PO(4)3- mixed solutions.

Polidocanol sclerotherapy for simple renal cysts.

Simple renal cysts were treated by aspiration and injection of the sclerosing agent 3% polidocanol (Aetoxisclerol) in 15 patients. All patients were followed up by ultrasound for 1-24 months. The age ranged from 35 to 81 years. There was 1 recurrence at 1 month. The efficacy of this treatment was 93%. Fourteen cysts completely disappeared, and no recurrence occurred after 1 year. Complications, such as microscopic hematuria, fever and infection, were not observed. The technique of polidocanol sclerotherapy was effective and safe.

Primary adenocarcinoma in the urethrorectal fistula.

A 60-year-old Japanese man was hospitalized because of urinary leakage from the anus on October 3, 1994. Retrograde urethrography detected a fistula between the bulbous urethra and the rectum. Urethrocystoscopy revealed a tumor on the urethrorectal fistula. Tumor biopsy showed a well differentiated adenocarcinoma. Cystourethrectomy with fistulectomy, and ileal conduit urinary diversion were performed. Pathological examination revealed primary adenocarcinoma in the fistula with invasion to the prostatic urethra and bladder wall. The patient showed no evidence of a recurrence as of August, 1996.

Quantitative rates of in vivo bone generation for Bioglass and hydroxyapatite particles as bone graft substitute.

Rates of in vivo bone generation were characterized by point-counting analysis of particulate Bioglass and synthetic hydroxyapatite (HA) in rabbit femora. New bony tissue was observed in approximately 20% of the image area around Bioglass particles at 1 wk, and the degree of trabecular bone growth increased with time. The interparticle space of Bioglass was filled by 80% bonding bone between 6 and 12 wk. The rate constants of trabecular bone growth in the presence of Bioglass were approximately 10.9x10(-3) d(-1) at the periphery of the implantation site. HA particles led to smaller rate constants of approximately 4.6x10(-3) d(-1) at the periphery, and the HA particles developed very small amounts of bridging bone. The quantitative rate of bone growth matched well with previously measured bioactive indices of the materials.

Etoposide, epirubicin and carboplatin in hormone-refractory prostate cancer.

Twelve patients with hormone-refractory prostate cancer were treated with combination chemotherapy of etoposide, epirubicin and carboplatin (EEC). At relapse, all patients had metastases to the bone and/or soft tissues. The median number of courses was 3 (range 1-10). Epirubicin was not administered in 6 patients because of heart disease. Three patients (25%) had a partial response and 8 (67%) showed no change. The overall response rate was 92%. Pain relief was observed in 4 patients (44%). Four patients were still alive after a mean observation period of 18 months (range 4-36 months), while 8 died with a mean survival period of 11 months (range 7-15 months). Nausea, appetite loss, and alopecia were observed in some patients. All except one patient experienced bone marrow suppression, 5 of whom were treated with granulocyte-colony stimulating factor. EEC chemotherapy in hormone-refractory prostate cancer is considered to be more effective than other kinds of chemotherapy, whereas it frequently induces bone marrow suppression.

Effect of varicocele on fertility potential: comparison between impregnating and nonimpregnating groups.

Sixty patients with varicocele, complaining of infertility, underwent a corrective operation. Eighteen (30%) of the 60 patients impregnated their mates (impregnating group). Sperm concentration significantly increased after the operation in the impregnating group (p < .05), but not in the patients who failed to impregnate their mates (nonimpregnating group). Sperm motility was not altered after the operation in these two groups. Sperm velocity significantly increased postoperatively in the impregnating group (p < .05), while linearity was not altered in either group. Sperm swelling significantly increased postoperatively in the impregnating group (p < .05), but not in the nonimpregnating group. Preoperative sperm parameters were not different between the two groups. Varicocele may disturb sperm function including sperm motion besides spermatogenesis and may impair the fertility potential. However, a prospective large-scale controlled study is required to obtain a definitive conclusion.

[Studies of transrectal prostatic ultrasonography on patients with male infertility].

The diagnostic significance of transrectal prostatic ultrasonography for chronic prostatitis and varicocele was evaluated in 380 male infertility patients. Of 20 patients with pyospermia, thought to be mainly caused by chronic prostatitis, 10.0 percent showed heterogeneous echo pattern of the prostate, while 25.0 percent showed capsular irregularity. Since 285 patients with non-infected semen showed similar sonographic findings, it is concluded that prostatic ultrasonography has little value in the diagnosis of chronic prostatitis in infertile patients. Enlarged periprostatic echo-free zone, thought to coincide with the dilatation of the Santrini's plexus, was found in 42.9 and 42.7 percent of patients with chronic prostatitis and varicocele, respectively, in contrast to 34.0 percent of patients without either diseases. Twelve percent of patients with varicocele showed highly enlarged echo-free zone, which was significantly more frequent compared to 5.0 percent in normal patients. Moreover, follow up of 4 patients with varicocele pre- and post-operatively found 2 of them to show a great improvement in the enlargement of the zone. These results suggest that varicocele may cause the dilation of the Santrini's plexus through a venous anastomosis in some patients and transrectal ultrasonography may be a useful tool in detecting small varicoceles in such patients.

Sclerotherapy of hydroceles with polidocanol.

Fifteen patients with hydroceles of the testis or spermatic cord were treated by aspiration and injection of the sclerosant solution polidocanol. The cure rate of hydroceles after one sclerotherapy session was 73%, and the overall cure rate using the procedure was 87%. No patient experienced pain during or after the procedure, which was conducted without anaesthesia. No complications were observed. It is concluded that sclerotherapy of hydroceles with polidocanol may be a useful alternative to open operation, due to its ease of administration, low frequency of complications, and high rate of effectiveness, and that this agent is preferable to certain other drugs in that it causes no pain during or after the injection.