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.

Monitoring of hemostatic abnormalities in major orthopedic surgery patients treated with edoxaban by APTT waveform.

INTRODUCTION: An analysis of the activated partial thromboplastin time (APTT) in major orthopedic surgery patients receiving edoxaban for the prevention of venous thromboembolism (VTE) was carried out. METHODS: The APTT waveform was analyzed in the above patients to monitor edoxaban administration. RESULTS: Of these 99 patients, 12 exhibited deep vein thrombosis, and 25 had massive bleeding. An increased biphasic pattern of the APTT waveform was observed after the administration of edoxaban, but there were no significant differences between the patients with and without complications. The peak times of acceleration, velocity, and 1/2 fibrin formation were significantly prolonged after the administration of edoxaban, especially in patients with massive bleeding, and were moderately correlated with the anti-Xa activity. While the heights of velocity and acceleration peak 2 were lower in patients receiving warfarin treatment than in those receiving edoxaban, the widths of these parameters were significantly longer. The height of 1/2 fibrin formation and the width of acceleration peaks 1 and 2 and the velocity were significantly increased after the administration of edoxaban. CONCLUSION: The peak time of the APTT waveform was significantly prolonged after the administration of edoxaban. The analysis of the APTT waveform may therefore be useful for the prediction of the risk of massive bleeding.

Uniaxial stress control of skyrmion phase.

Magnetic skyrmions, swirling nanometric spin textures, have been attracting increasing attention by virtue of their potential applications for future memory technology and their emergent electromagnetism. Despite a variety of theoretical proposals oriented towards skyrmion-based electronics (that is, skyrmionics), few experiments have succeeded in creating, deleting and transferring skyrmions, and the manipulation methodologies have thus far remained limited to electric, magnetic and thermal stimuli. Here, we demonstrate a new approach for skyrmion phase control based on a mechanical stress. By continuously scanning uniaxial stress at low temperatures, we can create and annihilate a skyrmion crystal in a prototypical chiral magnet MnSi. The critical stress is merely several tens of MPa, which is easily accessible using the tip of a conventional cantilever. The present results offer a new guideline even for single skyrmion control that requires neither electric nor magnetic biases and consumes extremely little energy.

Efficiency of diversion of the first aliquot of blood and prestorage leukoreduction for preventing bacterial contamination in red blood cell concentrates assessed using a rapid polymerase chain reaction-based bacterial detection system.

OBJECTIVES: Sepsis caused by the bacterial contamination of blood products is a major infection risk associated with blood transfusion. Diversion of the initial 25 mL of blood and prestorage leukoreduction were implemented in Japan in 2007 for all donated blood products. We assessed the efficacy of these new collection procedures in preventing bacterial contamination of red blood cell (RBC) concentrates. METHODS: Broad-range 16S ribosomal RNA polymerase chain reaction was used to determine bacterial contamination in segment samples of RBCs before and after implementation of the new collection procedures. To evaluate whether these new procedures reduced bacterial contamination, we compared bacterial contamination rates of blood samples from diversion pouches with those of segment samples from the same donor's RBCs. RESULTS: The rate of bacterial contamination of RBCs before implementation of the new collection procedures was 1.27%. Most of the isolated bacteria were Staphylococcus epidermidis or Propionibacterium acnes. After implementation, this rate was significantly reduced to 0.10%. Of the 233 whole blood samples obtained from the Mie Red Cross Blood Center, 1.72% of blood samples from diversion pouches were contaminated, but no bacterial contamination was detected in segment samples from the same donor's RBCs after prestorage leukoreduction. CONCLUSIONS: The new collection procedure significantly reduced bacterial contamination of RBC concentrates.

Quantized hyperfine field at an implanted micro+ site in PrPb3: interplay between localized f electrons and an interstitial charged particle.

The local effect of an interstitial hydrogenlike particle on localized f electrons was studied in PrPb3 by means of micro+ spin rotation and relaxation. Spontaneous micro+ spin precession with harmonic frequencies was observed for the first time in f electron compounds. We demonstrate that the signal is derived from a coupling between the micro+ spin and the hyperfine-enhanced nuclear spin of nearest neighbor (NN) 141Pr with Ising-like anisotropy. The signal also suggests a marked suppression of spin dynamics of the NN 141Pr in comparison with that of the bulk 141Pr. These facts strongly indicate modification of the f electronic state due to the interstitial charged particle.

Coherence factors in a high-tc cuprate probed by quasi-particle scattering off vortices.

When electrons pair in a superconductor, quasi-particles develop an acute sensitivity to different types of scattering potential that is described by the appearance of coherence factors in the scattering amplitudes. Although the effects of coherence factors are well established in isotropic superconductors, they are much harder to detect in their anisotropic counterparts, such as high-superconducting-transition-temperature cuprates. We demonstrate an approach that highlights the momentum-dependent coherence factors in Ca2-xNaxCuO2Cl2. We used Fourier-transform scanning tunneling spectroscopy to reveal a magnetic-field dependence in quasi-particle scattering interference patterns that is sensitive to the sign of the anisotropic gap. This result is associated with the d-wave coherence factors and quasi-particle scattering off vortices. Our technique thus provides insights into the nature of electron pairing as well as quasi-particle scattering processes in unconventional superconductors.

Isolation and characterization of aminopeptidase from Capnocytophaga granulosa ATCC 51502.

There is evidence that enzymes from the genus Capnocytophaga play a role in dental calculus formation. Although most of the species in the genus produce aminopeptidases, there is a paucity of data on the purification and characterization of the enzyme, except in the case of Capnocytophaga gingivalis. The aim of this study was to purify aminopeptidase from culture supernatant of Capnocytophaga granulosa ATCC 51502, a new species of the genus. Purification was performed using ammonium sulfate fractionation and two chromatographic steps. The aminopeptidase was purified 158,433-fold with a yield of 12.0%. The enzyme appeared to be a trimer with a molecular mass of 270 kDa. The optimal pH of the aminopeptidase was 6.5 and its activity was completely inhibited by incubation at 50 degrees C for 10 min. The enzyme showed maximum specificity for basic amino acids (Arg and Lys) and also hydrolyzed noncharged amino acids (Met, Leu and Ala). Ca(2+), Zn(2+) and Fe(3+) activated the enzyme, while EDTA, Ag(+), Hg(+) and Cu(2+) inhibited it. These results suggest that aminopeptidase of C. granulosa is different from that of C. gingivalis but similar to aminopeptidase B.

Staggered magnetism in LiV(2)O(4) at low temperatures probed by means of the muon Knight shift.

We report on measurement of the muon Knight shift in single crystals of LiV(2)O(4). Contrary to what is anticipated for the heavy fermion state based on the Kondo mechanism, the presence of inhomogeneous local magnetic moments is demonstrated by the broad distribution of the Knight shift at temperatures well below the presumed 'Kondo temperature' ([Formula: see text] K). Moreover, a significant fraction ([Formula: see text]) of the specimen gives rise to a second component which is virtually non-magnetic. These observations strongly suggest that the anomalous properties of LiV(2)O(4) originate from frustration of local magnetic moments.

Muonium as a shallow center in GaN.

A paramagnetic muonium (Mu) state with an extremely small hyperfine parameter was observed for the first time in single-crystalline GaN below 25 K. It has a highly anisotropic hyperfine structure with axial symmetry along the <0001> direction, suggesting that it is located either at a nitrogen-antibonding or a bond-centered site oriented parallel to the c axis. Its small ionization energy (

Elimination of chrysanthemum stunt viroid from an infected chrysanthemum cultivar by shoot regeneration from a leaf primordium-free shoot apical meristem dome attached to a root tip.

In this research we eliminated chrysanthemum stunt viroid (CSVd) from a highly infected chrysanthemum cultivar using a newly established method. 'Piato' is one of the most difficult cultivars in which to obtain CSVd-free plants by conventional methods. Leaf primordium-free shoot apical meristems (LP-free SAMs) of 'Piato' plants were dissected and attached to CSVd-free chrysanthemum or cabbage root tips. As shown by nested-PCR, CSVd was not detected in some shoots regenerated on both types of root tip. The production rates of CSVd-free plants using chrysanthemum and cabbage root tips were 14% and 3%, respectively. Regeneration of plants from LP-free SAMs of chrysanthemum plants by attaching these SAMs to root tips is an efficient method of generating CSVd-free chrysanthemum plants.

Time-reversal symmetry-breaking superconductivity in heavy-fermion PrOs4Sb12 detected by muon-spin relaxation.

We report on muon-spin relaxation measurements of the 4f(2)-based heavy-fermion superconductor filled-skutterudite Pr(Os4Sb12. The results reveal the spontaneous appearance of static internal magnetic fields below the superconducting transition temperature, providing unambiguous evidence for the breaking of time-reversal symmetry in the superconducting state. A discussion is made on which of the spin or orbital component of Cooper pairs carries a nonzero momentum.

Notch signalling in hematopoiesis.

The Notch pathway is a widely utilized, evolutionarily conserved regulatory system that plays a central role in the fate decisions of multipotent precursor cells. Notch often acts by inhibiting differentiation along a particular pathway while permitting or promoting self-renewal or differentiation along alternative pathways. Haematopoietic cells and stromal cells express Notch receptors and their ligands, and Notch signalling affects the survival, proliferation, and fate choices of precursors at various stages of haematopoietic development, including whether haematopoietic stem cells self-renew or differentiate, common lymphoid precursors undergo T or B cell differentiation, or monocytes differentiate into macrophage or dendritic cells. These findings suggest that the Notch pathway plays a fundamental role in regulating haematopoietic development.

The notch pathway: modulation of cell fate decisions in hematopoiesis.

The hematopoietic system is maintained by a rare population of hematopoietic stem cells (HSC) that are thought to undergo self-renewal as well as continuously produce progeny that differentiate into the various hematopoietic lineages. However, the mechanisms regulating cell fate choices by HSC and their progeny have not been understood. Results of most studies support a stochastic model of cell fate determination in which growth factors support only the survival or proliferation of the progeny specified along a particular lineage. In other developmental systems, however, Notch signaling has been shown to play a central role in regulating fate decisions of numerous types of precursors, often inhibiting a particular (default) pathway while permitting self-renewal or differentiation along an alternative pathway. There is also accumulating evidence that the Notch pathway affects survival, proliferation, and cell fate choices at various stages of hematopoietic cell development, including the decisions of HSC to self-renew or differentiate and of common lymphoid precursors to undergo T- or B-cell differentiation. These data suggest that the Notch pathway plays a fundamental role in the development and maintenance of the hematopoietic system.

Efficient ex vivo generation of human dendritic cells from mobilized CD34+ peripheral blood progenitors.

We tried to efficiently generate human dendritic cells (DCs) from CD34+ peripheral blood hematopoietic progenitor cells mobilized by high-dose chemotherapy and subsequent administration of granulocyte colony-stimulating factor, using a liquid suspension culture system. Among various combinations, the combination of c-kit ligand, flt-3 ligand, c-mpl ligand (TPO), and interleukin (IL)-4 most potently generated the number of CD1a+CD14- DCs in cultures containing granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor alpha (TNF-alpha). The delayed addition of IL-4 on day 6 of culture gave rise to an additional increase in the yield of CD1a+CD14-DCs that were characterized by the expression of HLA-ABC, HLA-DR, CD80, CD86, and CD83. The majority of the sorted CD1a-CD14+ cells derived from 6-day culture of CD34+ cells gave rise to CD1a+CD14- DCs and CD1a-CD14+ macrophages on day 12 of culture in the presence and absence of IL-4, respectively. These findings suggest that IL-4 promotes the differentiation of CD1a- CD14+ cells derived from mobilized CD34+ peripheral blood hematopoietic progenitors to CD1a+ CD14- DCs. The majority of these DCs expressed CD68 but not the Langerhans-associated granule antigen, a finding that suggests they emerge through the monocyte differentiation pathway. The addition of TPO and IL-4 to cultures did not affect the potential of DCs to stimulate the primary allogeneic T-cell response. These findings demonstrated that the combination of c-kit ligand plus flt-3 ligand plus TPO with GM-CSF plus TNF-alpha, followed by IL-4, is useful for ex vivo generation of human DCs from mobilized CD34+ peripheral blood progenitors.

Dominant effect of supplemented-sucrose on the low protein diet-induced increase in blood pressure of Sprague-Dawley rats.

A low-protein diet (LPD) is known to affect the regulation of hemodynamics, and could contribute to the genesis of hypertension. We investigated the mechanism for the LPD-induced elevation of blood pressure in 52 Sprague-Dawley rats. Rats fed the LPD for 8 weeks showed a significantly higher blood pressure than those fed on a normal-protein diet (NPD) when the LPD included sucrose as a predominant component of carbohydrate (LPD with a high sucrose content, 135 +/- 2 mmHg; NPD, 124 +/- 2 mmHg; p<0.05). However, LPD with a low sucrose content, in which corn starch was the main component of carbohydrate, did not have a hypertensive effect (125 +/- 2 mmHg). Urinary epinephrine and norepinephrine excretion was significantly higher in the LPD high-sucrose group than in the NPD and LPD low-sucrose groups, and there was a significant positive correlation between urinary norepinephrine excretion and systolic blood pressure. Urinary nitric oxide excretion was no different between these groups, and 2 % L-arginine administration exerted no antihypertensive effect on the LPD-induced elevation of blood pressure. Sodium restriction also did not attenuate the LPD-induced elevation of blood pressure. These results suggest that the effect of LPD on blood pressure could be interpreted as the effect of the high sucrose content supplemented to the LPD rather than the direct effect of protein restriction, and that the stimulation of sympathetic nervous activity was associated with this elevation of blood pressure.

Microdialysis measurement of ascorbic acid in rabbit vitreous after photodynamic reaction.

A method for long-term intravitreous microdialysis was used to measure endogenous reduced ascorbic acid in the vitreous of rabbits by HPLC-ECD before and after exposure to intense visible light in the presence of fluorescein. Cellulose microdialysis probes were implanted into the vitreous humor of each eye and after stabilization ascorbic acid measurements were recorded over a 14 day period. Under this experimental condition, normal ascorbic acid concentrations in vitreous varied from 98.0 +/- 9.8 to 106.9 +/- 20.3 microM(mean +/- S.D.). The eyes received light irradiation (25 000 lux) for 2 hr and fluorescein was used as the photosensitizer once or twice. No immediate effects on ascorbic acid concentrations could be observed in the eyes irradiated twice without fluorescein i.v. injections and in the twice fluorescein injected without irradiation. However, in the eyes irradiated once with fluorescein (30 mg kg(-1)), ascorbic acid concentration after irradiation significantly decreased from day 2 and continued over a period of 10 days compared with that before irradiation and maximal reduction was 32.6% (P < 0.005) on day 6 after irradiation. By day 13, the ascorbic acid concentration returned to control levels (P > 0.01). In the eyes irradiated twice with fluorescein injections, ascorbic acid concentration after irradiation decreased even more over the experimental period and the maximal reduction was 65.5% (P < 0.005) on day 5 after irradiation and did not recover over the next 9 days. In the eyes irradiated twice with fluorescein injections plus administration of ascorbic acid (150 mg kg(-1)) 30 min before irradiation, a significant increase (52.5%) of ascorbic acid (P < 0.005) was found on day 1 and control levels of ascorbic acid were maintained from day 2 onward. The protective role of ascorbic acid in the vitreous humor against photodynamic reaction is suggested.