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We demonstrated the generation of the intense radially polarized mid-infrared optical vortex at a wavelength of 10.6 µm by use of a passive axially symmetric zinc selenide (ZnSe) waveplate with high energy pulse throughput. The phase of the radially polarized optical vortex with the degree of polarization of 0.95 was spirally distributed in regard to the angle. The converted laser beam energy of about 2.6 mJ per pulse was obtained at the input pulse energy of 4.9 mJ, corresponding to the energy conversion efficiency of 56%. [ABSTRACT FROM AUTHOR]

We have succeeded in growing the ZnO microspheres by a simple laser ablation in the air, and we have obtained UV whispering-gallery-mode (WGM) lasing from the sphere under pulsed laser excitation. In this study, we observed resonances of WGM in visible region under cw laser pumping. In addition, possible refractive index of the ZnO microsphere was estimated from the WGM peaks. Furthermore, we obtained room-temperature electroluminescence from the ZnO microsphere/p-GaN heterojunction under forward bias. [ABSTRACT FROM AUTHOR]

The (Pr1-yYy)0.7Ca0.3CoO3 (y ≥ 0.0625) compounds show a first-order metal-insulator (MI) transition and simultaneous spin-state (SS) transition upon a change in the temperature. We have measured the electrical resistivity of the samples with y = 0.075 (the transition temperature, TMI = 64 K) and 0.10 (TMI = 93 K) in ultrahigh magnetic fields of up to 120 T using a contactless radio-frequency transmission technique. We observed a magnetic-field-induced insulator-metal (IM) transition with large hysteresis below TMI and obtained the temperature-magnetic field phase diagrams. A possible mechanism of the field-induced IM and SS transitions is discussed. [ABSTRACT FROM AUTHOR]

Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50-200 lmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10-50 lm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs. [ABSTRACT FROM AUTHOR]

In-stent restenosis (ISR) is a prevalent problem following stenting of femoropopliteal lesions. A potential novel treatment modality for ISR including excimer laser atherectomy (ELA) has become available. We performed ELA for in-stent chronic total occlusion (CTO) of femoropopliteal lesions and evaluated lesion morphology before and after ELA by angioscopy in 2 patients. The angioscopic findings clearly showed removal of in-stent thrombi after ELA. Thus, ELA may be effective for in-stent CTO of femoropopliteal lesions. This is the first report describing the direct visualization of ELA effect for vaporization of thrombi in femoropopliteal in-stent lesions by angioscopy. [ABSTRACT FROM AUTHOR]

Aminated cellulose nanofibers (CNFs) were prepared by attaching diaminoethane or polyethyleneimine onto microfibrillated CNFs and used for the selective removal of endotoxins (lipopolysaccharides; LPSs) from acidic protein solutions. The adsorption of the LPSs was measured at pH 7.0 and an ionic strength (®) of 0.2. The diaminoethane-immobilized CNFs (amino group content of 0.9 meq g-1) selectively removed LPSs from protein solutions (isoelectric point (pI) 4.9-11.0) without adsorption of the proteins. [ABSTRACT FROM AUTHOR]

We have succeeded in controlling growth density of the ZnO nanowires by introduction of a ZnO buffer layer. Low-density hexagonal cone-shape ZnO cores are formed on the buffer layer, and vertically-aligned ZnO nanowires are grown on the cores. The density of the nanowires was decreased by laser irradiation to the buffer layer before growth of the ZnO nanowires. In addition, periodic growth of ZnO nano-crystals was demonstrated using four beam interference patterning. [ABSTRACT FROM AUTHOR]

We have succeeded in synthesizing ZnO nano/microspheres by a simple laser ablation method in the air and demonstrated whispering-gallery-mode (WGM) lasing from the ZnO sphere excited by a pulsed-ultraviolet laser beam. The spheres with diameters of up to 10μm were simply prepared by laser ablation of a ZnO sintered target by a Q-switched Nd:YAG laser in the air. In this study, we succeeded synthesizing large microspheres with diameters of larger than 20μm by the Nd:YAG laser without Q-switching. The mode spacing of the large sphere was in good agreement with the WGM theory. [ABSTRACT FROM AUTHOR]

A magneto-optical survey was conducted for HgCr2O4 powder samples under pulsed high magnetic fields of up to 55 T. Intensity changes in magnetic fields observed for the exciton-magnon-phonon optical transition spectra coincide well with those of magnetization, lattice distortion from X-ray diffraction, and electron-magnetic resonances. The lastordered phase was detected prior to the fully polarized magnetic phase, similarly to the other chromium spinel oxide, ZnCr2O4 and CdCr2O4. [ABSTRACT FROM AUTHOR]

Laser-assisted doping combined with annealing technique is used in selective areas to form a p–n junction on a SiC thin film grown by the pulsed laser deposition on a Si substrate at a temperature of 800 °C. This approach in an aluminum chloride solution and a phosphoric solution has resulted in p-SiC/n-Si and n-SiC/p-Si hetero-structures, respectively. Further, a functional in-plane p–n junction is realized side-by-side on the post-deposited SiC thin film. I–V characteristics by two probe technique showed the p–n diode characteristics. Blue light (400 nm) electroluminescence from the p–n junction on SiC thin film was observed in the forward biased condition. Further, an improvement in the I–V reverse characteristics was observed by illuminating the p–n SiC thin film with green/blue light. [ABSTRACT FROM AUTHOR]

Ultra-thick TaC-coated graphite prepared via a novel process was verified for use as a highly durable heater material in high-temperature and highly corrosive process environments such as those for SiC, GaN, and AlN bulk/epitaxial growth. As fundamental data for heater design, the temperature dependence of the electrical resistivity of the ultra-thick TaC layer was assessed. Estimation based on resistivity data indicates that the TaC-coated graphite heater element requires a slightly higher electrical current than that for conventional heaters. A coil-shaped ultra-thick TaC-coated heater for a MOCVD GaN growth system was fabricated using the proposed process. It was found to successfully heat the system to the target temperature for GaN epilayer growth. The quality of the MOCVD-grown GaN epilayers obtained with the TaC-coated heater was confirmed to be almost identical to that of those obtained with a conventional heater in terms of crystallinity, thickness homogeneity, intrinsic defects, impurity incorporation, and contamination. [ABSTRACT FROM AUTHOR]

We describe the production of mid-infrared (mid-IR) short carbon dioxide (CO2) laser pulses with variable durations from 3 to 15 ns at a maximum pulse energy of 150 mJ/pulse using a germanium (Ge) substrate semiconductor switch and a multipass amplifier. The results clearly show the spectral profiles possess all of the desired characteristics as well as the possibility of obtaining an energy conversion efficiency close to the theoretical upper limit. It is also shown that it is necessary to irradiate with pulse durations less than 10 ns to optimize efficient EUV emission using Sn and Gd targets. [ABSTRACT FROM AUTHOR]

It is expected that 2020 Tokyo Olympic and Paralympic Games will be held in hot and humid environment. However, athletes need to maximize their athletic performance in the Olympic and Paralympic Games regardless of whether condition. In this symposium, we introduced our ongoing special research project for 2020 Tokyo Olympic and Paralympic Games at JISS, and especially this time, we would like to present our research on caffeine's ergogenic effects on exercise performance in hot and humid environments. Caffeine is widely known for its ergogenic effects on exercise performance. To date, many scientific researches have demonstrated ergogenic effects of caffeine on athletic performances in thermo-neutral condition. However, to date, there is little evidence of an ergogenic effect of caffeine in hot and humid environment. Thus, we investigated the effect of low dose of caffeine on intermittent sprint cycle performance. There was a significant main effect of the condition on total power output (caffeine vs placebo, p< 0.05). Moreover, seven out of eight subjects increased total mean power by caffeine ingestion compared to the control condition. In conclusion, there is a possibility that caffeine intake prior to prolonged intermittent exercise is useful for countermeasures for who want to maximize their performance in hot and humid environments. [ABSTRACT FROM AUTHOR]

The magnetization processes of the spin-3/2 antiferromagnet LiInCr4O8 comprising a "breathing" pyrochlore lattice, which is an alternating array of small and large tetrahedra, are studied under ultrahigh magnetic fields of up to 130 T using state-of-the-art pulsed magnets. A half magnetization plateau is observed above 90 T to 130 T, suggesting that LiInCr4O8 has a strong spin-lattice coupling, similar to conventional chromium spinel oxides. The magnetization of LiGa0.125In0.875Cr4O8, in which the structural and magnetic transitions at low temperatures have been completely suppressed, shows a sudden increase above 13 T, indicating that a spin gap of 2.2 meV exists between a tetramer singlet ground state and an excited state with total spin 1, with the latter being stabilized by the application of a magnetic field. The breathing pyrochlore antiferromagnet is found to be a unique frustrated system with strong spin-lattice coupling and bond alternation. [ABSTRACT FROM AUTHOR]

Here, we propose a halogen-free vapor phase epitaxy (HF-VPE) technique to grow bulk GaN single crystals. This technique employs the simplest reaction for GaN synthesis (reaction of Ga vapor with NH3) and can potentially achieve a high growth rate, a prolonged growth duration, a high crystal quality, and a low cost. The analyses of thick HF-VPE-GaN layers grown under optimized growth conditions revealed that high-quality crystals, both in terms of dislocation density and impurity concentration, are obtained at high growth rates of over 100 µm/h. [ABSTRACT FROM AUTHOR]

We succeeded in synthesizing antimony (Sb)-doped zinc oxide (ZnO) microspheres by ablating a sintered ZnO target containing Sb in air. The structural properties of the microspheres were investigated by Raman scattering studies. The Zn–Sb related local vibrational mode (LVM) was detected around 238 cm−1. Room-temperature photoluminescence (PL) properties of the microspheres were investigated under cw and pulsed laser excitations, and ultraviolet (UV) emission and whispering-gallery-mode (WGM) lasing were observed from the microspheres. Furthermore, a p–n heterojunction was formed between a single Sb-doped ZnO microsphere and an n-Al-doped ZnO thin film, and a good rectifying property with a turn-on voltage of approximately 1.8 V was observed in the current–voltage (I–V) characteristics across the junction. [ABSTRACT FROM AUTHOR]

Adult T cell leukemia/lymphoma (ATL) is an aggressive peripheral T cell neoplasm with very poor prognosis. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been reported as a curative treatment modality for ATL. However, there are no reports comparing chemotherapy alone with allo-HSCT in ATL. In this report, we retrospectively analyzed data for patients treated with (n = 29, median age 55 years) or without allo-HSCT (n = 37, median age 58 years) for ATL in Kagoshima University Hospital, located in one of the most endemic areas of human T cell lymphotropic leukemia virus type 1 infection. Forty patients (61%) started coordination for allo-HSCT. Ten patients (34.4%) received allo-HSCT while in complete remission (CR), whereas the others were not in CR. Twenty-five patients (86.2%) received reduced-intensity conditioning, and the others received myeloablative conditioning. With a median follow-up period for survivors of 41 months (range, 5 to 125 months), the 3-year overall survival (OS) rate from first chemotherapy for all patients (with or without allo-HSCT) was 35.2%. The 3-year OS from first chemotherapy for patients who received allo-HSCT or only chemotherapy was 44.9% and 27.7%, respectively. Univariate analyses revealed that high serum soluble IL-2 receptor (sIL-2R) levels (≥2000 U/mL) just before the conditioning regimen and progressive disease (PD) status at HSCT (according to Japan Clinical Oncology Group Study 0907 criteria) were significant risk factors for OS in the allo-HSCT group. Multivariate analyses revealed that PD status was a significant risk factor for OS in the allo-HSCT group. In the chemotherapy-only group, the 3-year OS rate was 61.5% (95% CI, 30.8% to 81.8%) in patients with serum sIL-2R levels < 2000 U/mL for >3 months. In contrast, the 3-year OS rate was 5.7% (95% CI, .4% to 22.4%) in patients who did not achieve serum sIL-2R levels < 2000 U/mL for >3 months. Our single-center cohort experience indicates that chemosensitivity is the most important prognostic factor for OS in ATL patients and the use of allo-HSCT is limited in chemorefractory patients with aggressive ATL disease. In the chemosensitive patients, allo-HSCT demonstrated a tendency toward better OS. Further clinical studies are warranted to determine optimal treatments for patients who are less sensitive to conventional chemotherapy. [ABSTRACT FROM AUTHOR]

The magnetic phases of a triangular-lattice antiferromagnet CuCrO2 were investigated in magnetic fields along the c axis, H∥[001], up to 120 T. Faraday rotation and magnetoabsorption spectroscopy were used to unveil the rich physics of magnetic phases. An up-up-down (UUD) magnetic structure phase was observed around 90-105 T at temperatures around 10 K. Additional distinct anomalies adjacent to the UUD phase were uncovered and the Y-shaped and the V-shaped phases are proposed to be viable candidates. These ordered phases emerged as a result of the interplay of geometrical spin frustration, single-ion anisotropy, and thermal fluctuations in an environment of extremely high magnetic fields. [ABSTRACT FROM AUTHOR]