Laser-based angle-resolved photoemission spectroscopy with micrometer spatial resolution and detection of three-dimensional spin vector.

We have developed a state-of-the-art apparatus for laser-based spin- and angle-resolved photoemission spectroscopy with micrometer spatial resolution (µ-SARPES). This equipment is realized by the combination of a high-resolution photoelectron spectrometer, a 6 eV laser with high photon flux that is focused down to a few micrometers, a high-precision sample stage control system, and a double very-low-energy-electron-diffraction spin detector. The setup achieves an energy resolution of 1.5 (5.5) meV without (with) the spin detection mode, compatible with a spatial resolution better than 10 µm. This enables us to probe both spatially-resolved electronic structures and vector information of spin polarization in three dimensions. The performance of µ-SARPES apparatus is demonstrated by presenting ARPES and SARPES results from topological insulators and Au photolithography patterns on a Si (001) substrate.

Publisher Correction: A weak topological insulator state in quasi-one-dimensional bismuth iodide.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A weak topological insulator state in quasi-one-dimensional bismuth iodide.

The major breakthroughs in understanding of topological materials over the past decade were all triggered by the discovery of the Z2-type topological insulator-a type of material that is insulating in its interior but allows electron flow on its surface. In three dimensions, a topological insulator is classified as either 'strong' or 'weak'1,2, and experimental confirmations of the strong topological insulator rapidly followed theoretical predictions3-5. By contrast, the weak topological insulator (WTI) has so far eluded experimental verification, because the topological surface states emerge only on particular side surfaces, which are typically undetectable in real three-dimensional crystals6-10. Here we provide experimental evidence for the WTI state in a bismuth iodide, ß-Bi4I4. Notably, the crystal has naturally cleavable top and side planes-stacked via van der Waals forces-which have long been desirable for the experimental realization of the WTI state11,12. As a definitive signature of this state, we find a quasi-one-dimensional Dirac topological surface state at the side surface (the (100) plane), while the top surface (the (001) plane) is topologically dark with an absence of topological surface states. We also find that a crystal transition from the ß-phase to the α-phase drives a topological phase transition from a nontrivial WTI to a normal insulator at roughly room temperature. The weak topological phase-viewed as quantum spin Hall insulators stacked three-dimensionally13,14-will lay a foundation for technology that benefits from highly directional, dense spin currents that are protected against backscattering.

Rotatable high-resolution ARPES system for tunable linear-polarization geometry.

A rotatable high-resolution angle-resolved photoemission spectroscopy (ARPES) system has been developed to utilize tunable linear-polarization geometries on the linear undulator beamline (BL-1) at Hiroshima Synchrotron Radiation Center. By rotating the whole ARPES measurement system, the photoelectron detection plane can be continuously changed from parallel to normal against the electric field vector of linearly polarized undulator radiation. This polarization tunability enables us to identify the symmetry of the initial electronic states with respect to the mirror planes, and to selectively observe the electronic states based on the dipole selection rule in the photoemission process. Specifications of the rotatable high-resolution ARPES system are described, as well as its capabilities with some representative experimental results.

Multiband One-Dimensional Electronic Structure and Spectroscopic Signature of Tomonaga-Luttinger Liquid Behavior in K_{2}Cr_{3}As_{3}.

We present angle-resolved photoemission spectroscopy measurements of the quasi-one-dimensional superconductor K_{2}Cr_{3}As_{3}. We find that the Fermi surface contains two Fermi surface sheets, with linearly dispersing bands not displaying any significant band renormalizations. The one-dimensional band dispersions display a suppression of spectral intensity approaching the Fermi level according to a linear power law, over an energy range of ∼200 meV. This is interpreted as a signature of Tomonoga-Luttinger liquid physics, which provides a new perspective on the possibly unconventional superconductivity in this family of compounds.

Thinning of articular cartilage after joint unloading or immobilization. An experimental investigation of the pathogenesis in mice.

OBJECTIVE: Moderate mechanical stress generated by normal joint loading and movement is essential for the maintenance of healthy articular cartilage. However, the effects of reduced loading caused by the absence of weight bearing or joint motion on articular cartilage and subchondral bone is still poorly understood. We aimed to characterize morphological and metabolic responses of articular cartilage and subchondral bone to decreased mechanical stress in vivo. METHODS: Mice were subjected to periods of hindlimb unloading by tail suspension or external fixation of the knee joints. The articular surface was observed with digital microscope and the epiphyseal bone was assessed by micro-CT analysis. Articular cartilage and subchondral bone were further evaluated by histomorphometric, histochemical, and immunohistochemical analyses. RESULTS: The joint surface was intact, but thickness of both the total and uncalcified layer of articular cartilage were decreased both after joint unloading and immobilization. Subchondral bone atrophy with concomitant marrow expansion predisposed osteoclast activity at bone surface to invade into cartilaginous layer. Uncalcified cartilage showed decreased aggrecan content and increased aggrecanase expression. Alkaline phosphatase (ALP) activity was increased at uncalcified cartilage, whereas decreased at calcified cartilage. The distributions of hypertrophic chondrocyte markers remained unchanged. CONCLUSION: Thinning of articular cartilage induced by mechanical unloading may be mediated by metabolic changes in chondrocytes, including accelerated aggrecan catabolism and exquisitely modulated matrix mineralization, and cartilage matrix degradation and resorption by subchondral osteoclasts. Cartilage degeneration without chondrocyte hypertrophy under unloading condition indicate the possible existence of mechanism which is different from osteoarthritis pathogenesis.

High-energy anomaly in the band dispersion of the ruthenate superconductor.

We reveal a "high-energy anomaly" (HEA) in the band dispersion of the unconventional ruthenate superconductor Sr2RuO4, by means of high-resolution angle-resolved photoemission spectroscopy (ARPES) with tunable energy and polarization of incident photons. This observation provides another class of correlated materials exhibiting this anomaly beyond high-T(c) cuprates. We demonstrate that two distinct types of band renormalization associated with and without the HEA occur as a natural consequence of the energetics in the bandwidth and the energy scale of the HEA. Our results are well reproduced by a simple analytical form of the self-energy based on the Fermi-liquid theory, indicating that the HEA exists at a characteristic energy scale of the multielectron excitations. We propose that the HEA universally emerges if the systems have such a characteristic energy scale inside of the bandwidth.

Hexagonally deformed Fermi surface of the 3D topological insulator Bi2Se3.

A hexagonal deformation of the Fermi surface of Bi2Se3 has been for the first time observed by angle-resolved photoemission spectroscopy. This is in contrast to the general belief that Bi2Se3 possesses an ideal Dirac cone. The hexagonal shape is found to disappear near the Dirac node, which would protect the surface state electrons from backscattering. It is also demonstrated that the Fermi energy of naturally electron-doped Bi2Se3 can be tuned by 1% Mg doping in order to realize the quantum topological transport.

Interplay among Coulomb interaction, spin-orbit interaction, and multiple electron-boson interactions in Sr2RuO4.

Using polarization- and hν-dependent angle-resolved photoemission spectroscopy, we uncovered the fine details of a quasiparticle's dynamics of a typical multiband superconductor, Sr2RuO4. We found strong hybridization between the in-plane and out-of-plane quasiparticles via the Coulomb and spin-orbit interactions. This effect enhances the quasiparticle mass due to the inflow of out-of-plane quasiparticles into the two-dimensional Fermi surface sheet, where the quasiparticles are further subjected to the multiple electron-boson interactions. We suggest that the spin-triplet p-wave superconductivity of Sr2RuO4 is phonon mediated.

Isotopic fingerprint of electron-phonon coupling in high-Tc cuprates.

Angle-resolved photoemission spectroscopy with low-energy tunable photons along the nodal direction of oxygen isotope substituted Bi(2)Sr(2)CaCu(2)O(8+delta) reveals a distinct oxygen isotope shift near the electron-boson coupling "kink" in the electronic dispersion. The magnitude (a few meV) and direction of the kink shift are as expected due to the measured isotopic shift of phonon frequency, and are also in agreement with theoretical expectations. This demonstrates the participation of the phonons as dominant players, as well as pinpointing the most relevant of the phonon branches.

Electronic structure of charge- and spin-controlled Sr(1-(x+y))La(x+y)Ti(1-x)Cr(x)O3.

We present the electronic structure of Sr(1-(x+y))La(x+y)Ti(1-x)Cr(x)O3 investigated by high-resolution photoemission spectroscopy. In the vicinity of the Fermi level, it was found that the electronic structure was composed of a Cr 3d local state with the t(2g)3 configuration and a Ti 3d itinerant state. The energy levels of these Cr and Ti 3d states are well interpreted by the difference of the charge-transfer energy of both ions. The spectral weight of the Cr 3d state is completely proportional to the spin concentration x irrespective of the carrier concentration y, indicating that the spin density can be controlled by x as desired. In contrast, the spectral weight of the Ti 3d state is not proportional to y, depending on the amount of Cr doping.

Improved simultaneous nitrification and denitrification in a single reactor by using two different immobilization carriers with specific oxygen transfer characteristics.

To maximize nitrogen utilization rates during nitrification and denitrification in a simultaneous reaction for direct nitrogen removal from ammonia-nitrogen in a single reactor, two different carriers were applied that immobilized nitrifiers and denitrifiers separately. With the optimized DO concentration and mixing ratio of immobilization carriers, ammonium-nitrogen was successfully removed as designed until the middle phase of treatment where nitrogen removal rate was higher than 83% of the theoretical value, although an imbalance between nitrification and denitrification occurred at a later phase of treatment where residual nitrate-nitrogen concentration was less than 2 mg/l. The new approach using two different carriers to immobilize nitrifiers and denitrifiers separately was proved useful for controlling both nitrification and denitrification rates, enabling the utilization of maximum treatment ability of both nitrifiers and denitrifiers in a single reactor for direct nitrogen removal from ammonium-nitrogen.

Generalized synchronization of chaos in He-Ne lasers.

We experimentally demonstrate synchronization of chaos in one-way coupled He-Ne lasers with optical feedback. We observe different types of synchronization such as identical synchronization, inverse synchronization, and random amplification. These dynamics are maintained only for a short duration of several hundred milliseconds. We also observe generalized synchronization of chaos by using one master and two slave lasers. The generalized synchronization is achieved for a long duration of tens of seconds under injection locking. The generalized synchronization is always maintained while the injection locking is achieved.

[Serial changes in body composition in patients with chronic renal failure on peritoneal dialysis].

Nutritional status is one of the most important factors affecting mortality and morbidity in chronic dialysis patients. There are, however, few data on serial body composition changes in these patients. To investigate serial changes in body composition in patients on peritoneal dialysis, we measured intracellular fluid volume(ICF), extracellular fluid volume(ECF), body protein volume(BPV), body fat volume(BFV) and bone mineral content(BMC) using multifrequency bioelectrical impedance analysis (MF-BIA). MF-BIA was performed in 35 patients, consisting of 21 men and 14 women with a mean age of 51.3 +/- 10.9 years, before and after one year of observation. At the baseline in male patients, ICF was 37.0 +/- 3.4%, ECF 19.7 +/- 1.6%, BPV 20.7 +/- 1.7%, BFV 18.1 +/- 6.6% and BMC 4.5 +/- 0.4% of body weight, and in female patients ICF was 34.4 +/- 2.6%, ECF 17.8 +/- 1.9% BPV 19.0 +/- 1.6%, BFV 24.4 +/- 6.2% and BMC 4.5 +/- 0.4% of body weight. In the group of patients whose body weight increased more than 3 kilograms(n = 9), the increase rate of BFV was 32.3 +/- 20.2%, significantly higher than that of the other segments(p < 0.001). On the other hand, in the group of patients whose body weight decreased more than 3 kilograms(n = 5), each segment showed the same extent of decrease and there was no significant difference in the decrease rates among each segment. In the group of patients whose body weight was stable(n = 21), changes in each body composition segment were extremely small. It could be concluded that the body weight increase is due mainly to increase in BFV and body weight decrease results from a concurrent decrease in each body composition segment in peritoneal dialysis patients.

[Therapeutic outcome of spasmodic torticollis].

We investigated 117 patients with spasmodic torticollis who had visited us to seek for appropriate treatment in these 14 years. They were 71 men and 46 women, aged 44 +/- 14 (mean +/- SD) years, and suffered from this disorder during 4 +/- 5 years, maximum 26 years. Involuntary abnormal head positions, not only torticollis but also laterocollis and antero- or retrocollis, were contained in this study. Most of them were torticollis due to idiopathic focal dystonia. One or more courses of alcoholization therapy was accomplished in 82 patients who wished to be done. This therapy course consisted of about ten times totally of 99% ethanol injection to the motor point of two most hypertonic neck muscles, either side of the sternocleidomastoideus and the opposite side of the splenius in most cases, repeated every 2 or 3 weeks. One patient received as many as 98 times of this injection and resolved completely. Training to reinforce antagonistic muscles was also instructed. Twenty-one patients (26%) were resolved completely after this treatment. Fifty-four patients (66%) were ameliorated and satisfied partially, but 18 of them relapsed in 1 to 4 years after the treatment and were obliged to repeat one more course of this treatment. On the other hand, in five patients their torticollis improved under certain drug therapy alone. Sixteen patients (14%) gave up to continue the treatment within two months, and 14 patients (12%) dropped out before starting the therapy. This alcoholization therapy resulted in amelioration of torticollis in about 90% of the patients with a long effective period. Nevertheless, this alcohol injection is painful, and requires 5 to 6 months to be completed. In 2 patients who had already received many times of this injection, sudden hoarseness occurred one day immediately after the alcohol injection to the sternocleidomastoideus. This complication was presumably brought about by the unexpected infiltration of alcohol to the laryngeal area, located posterior to that muscle. They recovered in two months, but careful attention should be paid to the adverse effects. If botulinum toxin be available also in our country, we will be able to have another choice of therapy and the treatment of this disorder will become easier.

[Nerve conduction velocity of repeater F-waves is identical to that of M-waves].

F-wave normally varies in latency and waveform from one response to the next. But the number of identical responses in a series of F-waves may be increased with neurogenic atrophy consistent with a decreased number of motoneurons capable of responding to antidromic stimulation. They are called "repeater F-waves". We herein demonstrate some repeater F-waves observed in three patients with moderate or slight diabetic polyneuropathy. In their motor nerve conduction studies on the peroneal nerve the maximum conduction velocity was 33 m/sec in patient 1, 36 m/sec in patient 2 and 48 m/sec in patient 3. A total of 6 delayed indirect potentials were repeatedly evoked after nerve trunk stimulation. They fulfilled the characteristics of F-wave. Their conduction velocities in the leg segment were 27, 26, 23 m/sec in patient 1, 34, 33 m/sec in patient 2 and 46 m/sec in patient 3. Repeater F-waves are occasionally observed in patients with amyotrophic lateral sclerosis, cervical spondylosis or entrapment neuropathies, in which the number of motoneuron is decreased. In diabetic polyneuropathy some repeater F-waves were also observed in patients not only with moderate to severe neuropathy but also with normal nerve conduction. F-waves are generated by an antidromic backfiring of motor neurons, and they occur preferentially in large motor neurons. Larger motor neurons inhibit smaller axons through the activation of Renshaw cells. In our 3 patients conduction velocities of the repeated F-waves were all identical to the main component of M-wave. These observations reconfirmed the hypothesis that relatively large motor neurons generating F-waves are preferentially activated also in repeater F-waves.

[Serial change of TL/BMIPP dual SPECT myocardial scintigram in patients with acute myocardial infarction; meaning of chronic mismatch phenomenon].

This study was aimed to elucidate the serial changes and clinical significance of accumulation mismatch with TL and BMIPP dual SPECT myocardial scintigraphy during 6 months in patients with acute myocardial infarction (AMI). The dual SPECT scintigraphy was performed at one, three and six months after onset of AMI in 46 patients who underwent reperfusion therapy. Long axis fractional shortening in infarct-related area and left ventricular end-diastolic volume index (LVEDVI) were measured by left ventriculography performed immediately after reperfusion and at one, six months after onset of AMI. The patients were divided into two groups: those with mismatch (Group (+)) and those without (Group (-)) at one month after reperfusion. Group (+) was subdivided into three groups according to duration of persistence of mismatch; one month persistence (1 M), three months (3 M) and six months (6 M). Improvement of wall motion abnormality (WMA) in infarct-related area was seen at one month after reperfusion in group 1 M and group 3 M, while group 6 M showed no apparent change in WMA throughout the study period. LVEDI did not change at six months after reperfusion in group 1 M and 3 M, while significant increase was seen in group 6 M. It is concluded that the case with disappearance of mismatch between TL and BMIPP until three months after reperfusion indicates myocardial stunning while in the case with long-standing mismatch left ventricular remodeling is suggested.

[Comparative antimicrobial activity of RP 59,500 (quinupristin-dalfopristin), the first semisynthetic injectable streptgramin, against gram-positive cocci and other recent clinical pathogens].

RP 59,500 (Quinupristin-Dalfopristin) is the first semisynthetic injectable streptogramin antimicrobial agent, which is a combination of quinupristin and dalfopristin in a 30:70 ratio. The components of RP 59,500 act synergically to provide bactericidal activity through action at different sites on bacterial ribosomes. In the present study, the antimicrobial activity of RP 59,500 was compared with those of four macrolides (erythromycin, clarithromycin, azithromycin, roxithromycin). Susceptibility testing was carried out by microdilution method on 303 strains of 10 species, especially antibiotic-resistant Gram-positive cocci. RP 59,500 was active against a wide range of Gram-positive cocci including methicillin-resistant Staphylococci and penicillin-resistant Streptococcus pneumoniae. The MICs90 of RP 59,500 against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis were both 0.25 microgram/ml, although those of four macrolides were higher than 32 micrograms/ml. The MICs90 of RP 59,500 against penicillin-sensitive, -intermediate and -resistant S. pneumoniae were all 0.5 microgram/ml, although those of four macrolides against penicillin-resistant S. pneumoniae were higher than 32 micrograms/ml. RP 59,500 also exhibited equivalent activities to the four macrolides against strains of Streptococcus pyogenes. Streptococcus agalactiae and Moraxella catarrhalis. RP 59,500 exhibited the highest activities against Enterococcus faecalis, Enterococcus faecium and Enterococcus avium strains which are intrinsically resistant to most antimicrobial agents. No cross-resistance was observed between RP 59,500 and the four macrolides, which will merit attention in future clinical trials of the agent. The effect of human serum on the MIC of RP 59,500 was studied with strains of S. aureus, S. epidermidis and E. faecalis. The presence of 20% (V/V) serum had little or no effect on the MIC, although 50% (V/V) serum increased MICs by 4-8 folds. Laboratory-induced resistance to RP 59,500 occurred in a stepwise fashion in broth cultures of S. aureus, S. epidermidis and E. facalis strains and the induction rate was slow and no more than four fold increases were observed. Population analysis was performed on RP 59,500 and the reference macrolides against S. aureus ATCC 25,923 strain. Although low frequencies (less than 0.01%) of resistant sub-population were detected with EM, CAM, AZM and RXM, no RP 59,500-resistant sub-population was detected in this study.

Two unusual cases of a foreign body in the oral cavity caused by eating raw squid.

Foreign bodies are often encountered by otolaryngologists, but the oral cavity is considered a place where foreign bodies are rare because of its structural and functional features. We here present 2 cases with a foreign body in the oral cavity resulting from eating raw squid. In one of these 2 cases endoscopic examination revealed a gastric foreign body. The foreign bodies in the oral cavity were removed using forceps, together with surrounding mucous membrane. These foreign bodies were identified as sperm bulbs and discharging tube of sogittated calamary (Todarodes pacificus Steenstrup). Larva migrans of anisakiasis are to be differentiated from sperm bulbs; it is important to distinguish between the shape and size of the foreign body in our cases. If sperm bulbs are stuck in the oral cavity, it is necessary to remove them completely to ensure that inflammation is prevented. We stress the importance of checking not only anisakiasis but also sperm bulbs in humans who like eating raw squid.