Regulation of growth-defense balance by the JASMONATE ZIM-DOMAIN (JAZ)-MYC transcriptional module

The plant hormone jasmonate (JA) promotes the degradation of JASMONATE ZIM-DOMAIN (JAZ) proteins to relieve repression on diverse transcription factors (TFs) that execute JA responses. However, little is known about how combinatorial complexity among JAZ-TF interactions maintains control over myriad aspects of growth, development, reproduction, and immunity. We used loss-of-function mutations to define epistatic interactions within the core JA signaling pathway and to investigate the contribution of MYC TFs to JA responses in Arabidopsis thaliana. Constitutive JA signaling in a jaz quintuple mutant (jazQ) was largely eliminated by mutations that block JA synthesis or perception. Comparison of jazQ and a jazQ myc2 myc3 myc4 octuple mutant validated known functions of MYC2/3/4 in root growth, chlorophyll degradation, and susceptibility to the pathogen Pseudomonas syringae. We found that MYC TFs also control both the enhanced resistance of jazQ leaves to insect herbivory and restricted leaf growth of jazQ. Epistatic transcriptional profiles mirrored these phenotypes and further showed that triterpenoid biosynthetic and glucosinolate catabolic genes are up-regulated in jazQ independently of MYC TFs. Our study highlights the utility of genetic epistasis to unravel the complexities of JAZ-TF interactions and demonstrates that MYC TFs exert master control over a JAZ-repressible transcriptional hierarchy that governs growth-defense balance.

Comparative genomics of the tardigrades Hypsibius dujardini and Ramazzottius varieornatus

Tardigrada, a phylum of meiofaunal organisms, have been at the center of discussions of the evolution of Metazoa, the biology of survival in extreme environments, and the role of horizontal gene transfer in animal evolution. Tardigrada are placed as sisters to Arthropoda and Onychophora (velvet worms) in the superphylum Panarthropoda by morphological analyses, but many molecular phylogenies fail to recover this relationship. This tension between molecular and morphological understanding may be very revealing of the mode and patterns of evolution of major groups. Limnoterrestrial tardigrades display extreme cryptobiotic abilities, including anhydrobiosis and cryobiosis, as do bdelloid rotifers, nematodes, and other animals of the water film. These extremophile behaviors challenge understanding of normal, aqueous physiology: how does a multicellular organism avoid lethal cellular collapse in the absence of liquid water? Meiofaunal species have been reported to have elevated levels of horizontal gene transfer (HGT) events, but how important this is in evolution, and particularly in the evolution of extremophile physiology, is unclear. To address these questions, we resequenced and reassembled the genome of H. dujardini, a limnoterrestrial tardigrade that can undergo anhydrobiosis only after extensive pre-exposure to drying conditions, and compared it to the genome of R. varieornatus, a related species with tolerance to rapid desiccation. The 2 species had contrasting gene expression responses to anhydrobiosis, with major transcriptional change in H. dujardini but limited regulation in R. varieornatus. We identified few horizontally transferred genes, but some of these were shown to be involved in entry into anhydrobiosis. Whole-genome molecular phylogenies supported a Tardigrada+Nematoda relationship over Tardigrada+Arthropoda, but rare genomic changes tended to support Tardigrada+Arthropoda.

Production of rice straw hydrolysis enzymes by the fungi Trichoderma reesei and Humicola insolens using rice straw as a carbon source

Rice straw was evaluated as a carbon source for the fungi, Trichoderma reesei and Humicola insolens, to produce enzymes for rice straw hydrolysis. The enzyme activity of T. reesei and H. insolens cultivated in medium containing non-treated rice straw were almost equivalent to the enzyme of T. reesei cultivated in Avicel medium, a form of refined cellulose. The enzyme activity of T. reesei cultivated in medium containing NH₄OH-treated rice straw was 4-fold higher than enzyme from cultures grown in Avicel medium. In contrast, H. insolens enzyme from cultures grown in NH₄OH-treated rice straw had significantly lower activity compared with non-treated rice straw or Avicel. The combined use of T. reesei and H. insolens enzymes resulted in a significant synergistic enhancement in enzymatic activity. Our data suggest that rice straw is a promising low-cost carbon source for fungal enzyme production for rice straw hydrolysis.

Electron Number-Based Phase Diagram of Pr_{1-x}LaCe_{x}CuO_{4-δ} and Possible Absence of Disparity between Electron- and Hole-Doped Cuprate Phase Diagrams

We performed annealing and angle resolved photoemission spectroscopy studies on electron-doped cuprate Pr_{1-x}LaCe_{x}CuO_{4-δ} (PLCCO). It is found that the optimal annealing condition is dependent on the Ce content x. The electron number (n) is estimated from the experimentally obtained Fermi surface volume for x=0.10, 0.15 and 0.18 samples. It clearly shows a significant and annealing dependent deviation from the nominal x. In addition, we observe that the pseudo-gap at hot spots is also closely correlated with n; the pseudogap gradually closes as n increases. We established a new phase diagram of PLCCO as a function of n. Different from the x-based one, the new phase diagram shows similar antiferromagnetic and superconducting phases to those of hole doped ones. Our results raise a possibility for absence of disparity between the phase diagrams of electron- and hole-doped cuprates.

House dust mite sublingual tablet is effective and safe in patients with allergic rhinitis

BACKGROUND

House dust mite (HDM) is the major indoor allergen for allergic diseases such as allergic rhinitis (AR) and asthma. Although sublingual immunotherapy is a curative treatment for HDM-induced AR, data from large-scale studies are limited. We evaluated the efficacy and safety of HDM tablets in adolescent and adult patients (aged 12-64 years) with HDM-induced AR with or without intermittent asthma.

METHODS

In a double-blind trial in Japan, 968 subjects were randomized 1 : 1 : 1 to 300 index of reactivity (IR), 500 IR, or placebo groups. The primary endpoint was the Average Adjusted Symptom Score (AASS) in the last eight weeks of the 52-week treatment. Secondary endpoints included individual nasal and ocular symptom scores, rescue medication use, and the Japanese Rhinoconjunctivitis Quality of Life Questionnaire (JRQLQ) scores.

RESULTS

The AASS in the last eight weeks of treatment significantly improved in both the 300 IR and the 500 IR groups compared to that in the placebo group (P < 0.001). In the 300 IR group, the onset of action occurred at week 8-10. All four nasal symptoms significantly improved in both active treatment groups; rescue medication use and JRQLQ outcome improved in the 300 IR group. Most adverse events (AEs) were mild, and 16 serious AEs (SAEs) were reported; however, none of them were drug-related.

CONCLUSIONS

One-year treatment with 300 IR and 500 IR HDM tablets was effective without major safety concerns. The recommended therapeutic dose for AR is 300 IR.

Frameshift Mutation Confers Function as Virulence Factor to Leucine-Rich Repeat Protein from Acidovorax avenae

Many plant pathogens inject type III (T3SS) effectors into host cells to suppress host immunity and promote successful infection. The bacterial pathogen Acidovorax avenae causes brown stripe symptom in many species of monocotyledonous plants; however, individual strains of each pathogen infect only one host species. T3SS-deleted mutants of A. avenae K1 (virulent to rice) or N1141 (virulent to finger millet) caused no symptom in each host plant, suggesting that T3SS effectors are involved in the symptom formation. To identify T3SS effectors as virulence factors, we performed whole-genome and predictive analyses. Although the nucleotide sequence of the novel leucine-rich repeat protein (Lrp) gene of N1141 had high sequence identity with K1 Lrp, the amino acid sequences of the encoded proteins were quite different due to a 1-bp insertion within the K1 Lrp gene. An Lrp-deleted K1 strain (KΔLrp) did not cause brown stripe symptom in rice (host plant for K1); by contrast, the analogous mutation in N1141 (NΔLrp) did not interfere with infection of finger millet. In addition, NΔLrp retained the ability to induce effector-triggered immunity (ETI), including hypersensitive response cell death and expression of ETI-related genes. These data indicated that K1 Lrp functions as a virulence factor in rice, whereas N1141 Lrp does not play a similar role in finger millet. Yeast two-hybrid screening revealed that K1 Lrp interacts with oryzain α, a pathogenesis-related protein of the cysteine protease family, whereas N1141 Lrp, which contains LRR domains, does not. This specific interaction between K1 Lrp and oryzain α was confirmed by Bimolecular fluorescence complementation assay in rice cells. Thus, K1 Lrp protein may have acquired its function as virulence factor in rice due to a frameshift mutation.

Hydrolytic Stability of Self-etch Adhesives Bonded to Dentin

Functional monomers chemically interact with hydroxyapatite that remains within submicron hybrid layers produced by mild self-etch adhesives. The functional monomer 10-MDP interacts most intensively with hydroxyapatite, and its calcium salt appeared most hydrolytically stable, as compared with 4-MET and phenyl-P. We investigated the hypothesis that additional chemical interaction of self-etch adhesives improves bond stability. The micro-tensile bond strength (μTBS) of the 10-MDP-based adhesive did not decrease significantly after 100,000 cycles, but did after 50,000 and 30,000 cycles, respectively, for the 4-MET-based and the phenyl-P-based adhesives. Likewise, the interfacial ultrastructure was unchanged after 100,000 thermocycles for the 10-MDP-based adhesive, while that of both the 4-MET- and phenyl-P-based adhesives contained voids and less-defined collagen. The findings of this study support the concept that long-term durability of adhesive-dentin bonds depends on the chemical bonding potential of the functional monomer.

Development of a Self-etch Adhesive for Resin-modified Glass Ionomers

The favorable self-adhesiveness of resin-modified glass ionomers (RMGIs) might be even further improved if the time-consuming and technically sensitive etch-and-rinse pre-treatment step with polyalkenoic acids could be avoided. We undertook this study to assess the effectiveness of an experimental self-etch adhesive for RMGIs that does not need to be rinsed off. Ultrastructural analysis and micro-tensile bond strength testing to enamel and dentin of a RMGI restorative material and a RMGI adhesive were performed after 4 different surface pre-treatments: no conditioning; 25% polyalkenoic acid; an experimental self-etch adhesive; and 37.5% phosphoric acid followed by the experimental self-etch adhesive. The use of an experimental self-etch adhesive increased the bond strength of RMGIs, especially after an additional conditioning step. Interfacial analysis showed the formation of a thin hydroxyapatite-containing hybrid layer. The self-etch technique enhances the user-friendliness of RMGIs and lowers their technique-sensitivity, while maintaining desirable characteristics of the conventional etch-and-rinse approach with polyalkenoic acids.

Gel Phase Formation at Resin-modified Glass-ionomer/Tooth Interfaces

Ionic bonding between polyalkenoic acid and hydroxyapatite may explain the excellent bonding retention of glass-ionomers in clinical trials. We have here investigated the extent to which the self-adhesiveness of resin-modified glass-ionomers (RMGIs) can be attributed to this chemical bonding capacity. Therefore, the interaction of 3 RMGIs with tooth substrates was comprehensively characterized, with electron and atomic force microscopy correlated with x-ray photoelectron spectroscopy (XPS). Interfacial ultrastructural analysis for 2 RMGIs disclosed a shallow hybridization of hydroxyapatite-coated collagen, on which a submicron gel phase was deposited through reaction of the polyalkenoic acid with calcium extracted from the dentin surface. One RMGI, however, bonded to dentin without hybrid layer or gel phase formation. XPS indicated that polycarboxylic acids included in the RMGIs electrostatically interacted with hydroxyapatite. We conclude that the self-adhesiveness of RMGIs should be attributed to ionic bonding to hydroxyapatite around collagen, and to micro-mechanical interlocking for those RMGIs that additionally hybridize dentin.

Comparative Study on Adhesive Performance of Functional Monomers

Mild self-etch adhesives demineralize dentin only partially, leaving hydroxyapatite around collagen within a submicron hybrid layer. We hypothesized that this residual hydroxyapatite may serve as a receptor for chemical interaction with the functional monomer and, subsequently, contribute to adhesive performance in addition to micro-mechanical hybridization. We therefore chemically characterized the adhesive interaction of 3 functional monomers with synthetic hydroxyapatite, using x-ray photoelectron spectroscopy and atomic absorption spectrophotometry. We further characterized their interaction with dentin ultra-morphologically, using transmission electron microscopy. The monomer 10-methacryloxydecyl dihydrogen phosphate (10-MDP) readily adhered to hydroxyapatite. This bond appeared very stable, as confirmed by the low dissolution rate of its calcium salt in water. The bonding potential of 4-methacryloxyethyl trimellitic acid (4-MET) was substantially lower. The monomer 2-methacryloxyethyl phenyl hydrogen phosphate (phenyl-P) and its bond to hydroxyapatite did not appear to be hydrolytically stable. Besides self-etching dentin, specific functional monomers have additional chemical bonding efficacy that is expected to contribute to their adhesive potential to tooth tissue.

Spontaneous decays of magneto-elastic excitations in non-collinear antiferromagnet (Y,Lu)MnO3

Magnons and phonons are fundamental quasiparticles in a solid and can be coupled together to form a hybrid quasi-particle. However, detailed experimental studies on the underlying Hamiltonian of this particle are rare for actual materials. Moreover, the anharmonicity of such magnetoelastic excitations remains largely unexplored, although it is essential for a proper understanding of their diverse thermodynamic behaviour and intrinsic zero-temperature decay. Here we show that in non-collinear antiferromagnets, a strong magnon–phonon coupling can significantly enhance the anharmonicity, resulting in the creation of magnetoelastic excitations and their spontaneous decay. By measuring the spin waves over the full Brillouin zone and carrying out anharmonic spin wave calculations using a Hamiltonian with an explicit magnon–phonon coupling, we have identified a hybrid magnetoelastic mode in (Y,Lu)MnO₃ and quantified its decay rate and the exchange-striction coupling term required to produce it.

The properties of magnetic, crystalline solids can be described in terms of quantum particles of spin-wave and lattice-vibration energy, known as magnons and phonons respectively. Here, the authors show that strong magnon-phonon coupling in a noncollinear antiferromagnet can create magnetoelastic excitations.

Rewiring of jasmonate and phytochrome B signalling uncouples plant growth-defense tradeoffs

Plants resist infection and herbivory with innate immune responses that are often associated with reduced growth. Despite the importance of growth-defense tradeoffs in shaping plant productivity in natural and agricultural ecosystems, the molecular mechanisms that link growth and immunity are poorly understood. Here, we demonstrate that growth-defense tradeoffs mediated by the hormone jasmonate are uncoupled in an Arabidopsis mutant (jazQ phyB) lacking a quintet of Jasmonate ZIM-domain transcriptional repressors and the photoreceptor phyB. Analysis of epistatic interactions between jazQ and phyB reveal that growth inhibition associated with enhanced anti-insect resistance is likely not caused by diversion of photoassimilates from growth to defense but rather by a conserved transcriptional network that is hardwired to attenuate growth upon activation of jasmonate signalling. The ability to unlock growth-defense tradeoffs through relief of transcription repression provides an approach to assemble functional plant traits in new and potentially useful ways.

Type 2 diabetic patients with diabetic retinopathy and concomitant microalbuminuria showed typical diabetic glomerulosclerosis and progressive renal dysfunction

AIMS

To determine whether or not diabetic retinopathy (DR) in type 2 diabetic patients can predict the renal functional decline.

METHODS

We examined 32 normo-microalbuminuric type 2 diabetic patients by renal biopsy (23 men, age 49±10yrs) divided into two groups according to the presence (n=19) or absence (n=13) of DR. Electron microscopic morphometry including mesangial fractional volume [Vv(Mes/glom)] were performed and light microscopic tissues were categorized as: C1, normal/near normal renal structure; C2, typical diabetic glomerulopathy; C3, atypical injury patterns. Patients were followed up for 7.1±3.8years, and glomerular filtration rate (GFR) and urinary albumin excretion (UAE) measurements were taken annually.

RESULTS

Vv(Mes/glom) was larger in DR+ than that in DR-. Vv(Mes/glom) positively correlated with the UAE if patients had DR. The patients with DR had a significant higher rate of C2 pattern compared to those in DR-. Among patients with DR and C2, GFR in microalbuminuria (n=7) decreased while GFR in normoalbuminuria (n=5) did not change during the observation.

CONCLUSIONS

Type 2 diabetic patients with DR and C2 showed progressive renal dysfunction after they had microalbuminuria. DR and albuminuria should be considered to determine renal function decline in type 2 diabetic patients.

Role of Mfa5 in Expression of Mfa1 Fimbriae in Porphyromonas gingivalis

Fimbriae are protein-based filamentous appendages that protrude from the bacterial cell surface and facilitate host adhesion. Two types of fimbriae, FimA and Mfa1, of the periodontal pathogen Porphyromonas gingivalis are responsible for adherence to other bacteria and to host cells in the oral cavity. Both fimbrial forms are composed of 5 proteins, but there is limited information about their polymerization mechanisms. Here, the authors evaluated the function of Mfa5, one of the Mfa1 fimbrial accessory proteins. Using mfa5 gene disruption and complementation studies, the authors revealed that Mfa5 affects the incorporation of other accessory proteins, Mfa3 and Mfa4, into fibers and the expression of fimbriae on the cell surface. Mfa5 is predicted to have a C-terminal domain (CTD) that uses the type IX secretion system (T9SS), which is limited to this organism and related Bacteroidetes species, for translocation across the outer membrane. To determine the relationship between the putative Mfa5 CTD and the T9SS, mutants were constructed with in-frame deletion of the CTD and deletion of porU, a C-terminal signal peptidase linked to T9SS-mediated secretion. The ∆CTD-expressing strain presented a similar phenotype to the mfa5 disruption mutant with reduced expression of fimbriae lacking all accessory proteins. The ∆porU mutants and the ∆CTD-expressing strain showed intracellular accumulation of Mfa5. These results indicate that Mfa5 function requires T9SS-mediated translocation across the outer membrane, which is dependent on the CTD, and subsequent incorporation into fibers. These findings suggest the presence of a novel polymerization mechanism of the P. gingivalis fimbriae.

Effects of Cold Stimulation on Mitochondrial Activity and VEGF Expression in vitro

We aimed to clarify the effects of cold stimulation at various temperatures on mitochondrial activity and vascular endothelial growth factor (VEGF) expression in vitro. Human fibroblast, human mesenchymal stem cell, and rat skeletal muscle myoblast cell lines were used. For each cell type, cells were divided into 4 groups and stimulated in various cold temperatures (0, 4, 17 and 25°C) 3 times for 15 min each by placement on crushed ice or floating on cold water set at each temperature. Control cells were subjected to warm water at 37°C. Factors related to mitochondrial activity, mitochondrial DNA copy numbers, and VEGF expression were analyzed 24 h after the last cold stimulation. In all cell types, significant increases of factors related to mitochondrial activity and mitochondrial DNA copy numbers were seen in the 4°C and 17°C-stimulated cells compared with control cells. In rat skeletal muscle cells stimulated at 4°C, VEGF expression significantly increased compared to the control cells. Our data suggest that cold stimulation at certain temperatures promotes mitochondrial activity, biogenesis and VEGF expression.

A model of plasma current through a hole of Rogowski probe including sheath effects

In TST-2 Ohmic discharges, local current is measured using a Rogowski probe by changing the angle between the local magnetic field and the direction of the hole of the Rogowski probe. The angular dependence shows a peak when the direction of the hole is almost parallel to the local magnetic field. The obtained width of the peak was broader than that of the theoretical curve expected from the probe geometry. In order to explain this disagreement, we consider the effect of sheath in the vicinity of the Rogowski probe. A sheath model was constructed and electron orbits were numerically calculated. From the calculation, it was found that the electron orbit is affected by E × B drift due to the sheath electric field. Such orbit causes the broadening of the peak in the angular dependence and the dependence agrees with the experimental results. The dependence of the broadening on various plasma parameters was studied numerically and explained qualitatively by a simplified analytical model.

Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus-the 'D-shuttle' project

Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter 'D-shuttle' for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the terrestrial background radiation level of other regions/countries.

Screening out the non-Arrhenius behaviour of nematic-isotropic transition by room temperature ionic liquid

Differential Scanning Calorimetry (DSC) and optical polarization microscopy of a mixture of the liquid crystalline material (N-(4-methoxybenzylidene)-4-butylaniline, MBBA) and a Fe-based room temperature ionic liquid 1-ethyl-3-methylimidazolium tetrachloroferrate ([Emim](+) [FeCl4](-), EMIF) indicate a decrease in the nematic-isotropic (N-I) phase transition temperature (T(NI)) with an increase in EMIF concentration, explained by a proposed model of Coulomb "screening" of MBBA quadrupoles by the EMIF ions along with ionic "self screening." DSC studies of EMIF-MBBA and pure EMIF and comparison with pure MBBA results show that the major transitions in pure EMIF have Arrhenius behaviour, but more importantly the previously found convex Arrhenius behaviour of the pristine MBBA [K. Dan et al., Europhys. Lett. 108, 36007 (2014)] becomes Arrhenius in the mixture, indicating a conversion of the entropic N-I activation barrier to an enthalpic one. In presence of EMIF, a drastic decrease in the intensity of out-of-plane distortions of benzene rings in MBBA is found from Fourier transform infrared spectroscopy, consistent with significant reduction in the conformational states of MBBA. This suppression of large amplitude motion is again consistent with a Coulomb screening and gives a molecular basis for the entropic-to-enthalpic conversion of the N-I activation barrier.

Sphingosine kinase 1 is upregulated with lysophosphatidic acid receptor 2 in human colorectal cancer

AIM: To examine the expression of SphK1, an oncogenic kinase that produces sphingosine 1-phosphate (S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid (LPA) receptor overexpressed in various cancers, in human colorectal cancer.

METHODS: Real-time reverse-transcription polymerase chain reaction was used to measure the mRNA expression of SphK1, LPAR2, and the three major S1P receptors in 27 colorectal cancer samples and corresponding normal tissue samples. We also examined the correlation between the expression of SphK1 and LPAR2.

RESULTS: Colorectal cancer tissue in 22 of 27 patients had higher levels of SphK1 mRNA than in normal tissue. In two-thirds of the samples, SphK1 mRNA expression was more than two-fold higher than in normal tissue. Consistent with previous reports, LPAR2 mRNA expression in 20 of 27 colorectal cancer tissue samples was higher compared to normal tissue samples. Expression profiles of all three major S1P receptors, S1PR1, S1PR2, and S1PR3, varied without any trend, with no significant difference in expression between cancer and normal tissues. A highly significant positive correlation was found between SphK1 and LPAR2 expression [Pearson’s correlation coefficient (r) = 0.784 and P < 0.01]. The mRNA levels of SphK1 and LPAR2 did not correlate with TNM stage.

CONCLUSION: Our findings suggest that S1P and LPA may play important roles in the development of colorectal cancer via the upregulation of SphK1 and LPAR2, both of which could serve as new therapeutic targets in the treatment of colorectal cancer.

Recent developments of ion sources for life-science studies at the Heavy Ion Medical Accelerator in Chiba (invited)

With about 1000-h of relativistic high-energy ion beams provided by Heavy Ion Medical Accelerator in Chiba, about 70 users are performing various biology experiments every year. A rich variety of ion species from hydrogen to xenon ions with a dose rate of several Gy/min is available. Carbon, iron, silicon, helium, neon, argon, hydrogen, and oxygen ions were utilized between 2012 and 2014. Presently, three electron cyclotron resonance ion sources (ECRISs) and one Penning ion source are available. Especially, the two frequency heating techniques have improved the performance of an 18 GHz ECRIS. The results have satisfied most requirements for life-science studies. In addition, this improved performance has realized a feasible solution for similar biology experiments with a hospital-specified accelerator complex.

Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification

We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, and fullerene-chlorine-iron.

Development of a compact ECR ion source for various ion production

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.

Standardized Prevalence Ratios for Atrial Fibrillation in Adult Dialysis Patients in Japan

Background

While it is assumed that dialysis patients in Japan have a higher prevalence of atrial fibrillation (AF) than the general population, the magnitude of this difference is not known.

Methods

Standardized prevalence ratios (SPRs) for AF in dialysis patients (n = 1510) were calculated compared to data from the general population (n = 26 454) living in the same area.

Results

The prevalences of AF were 3.8% and 1.6% in dialysis patients and the general population, respectively. In male subjects, these respective values were 4.9% and 3.3%, and in female subjects they were 1.6% and 0.6%. The SPRs for AF were 2.53 (95% confidence interval [CI], 1.88–3.19) in all dialysis patients, 1.80 (95% CI, 1.30–2.29) in male dialysis patients, and 2.13 (95% CI, 0.66–3.61) in female dialysis patients.

Conclusions

The prevalence of AF in dialysis patients was twice that in the population-based controls. Since AF strongly contributes to a higher risk of cardiovascular mortality and morbidity in the general population, further longitudinal studies should be conducted regarding the risk of several outcomes attributable to AF among Japanese dialysis patients.

Raman and fluorescence characteristics of resonant inelastic X-ray scattering from doped superconducting cuprates

Measurements of spin excitations are essential for an understanding of spin-mediated pairing for superconductivity; and resonant inelastic X-ray scattering (RIXS) provides a considerable opportunity to probe high-energy spin excitations. However, whether RIXS correctly measures the collective spin excitations of doped superconducting cuprates remains under debate. Here we demonstrate distinct Raman- and fluorescence-like RIXS excitations of Bi_1.5Pb_0.6Sr_1.54CaCu₂O_8+δ. Combining photon-energy and momentum dependent RIXS measurements with theoretical calculations using exact diagonalization provides conclusive evidence that the Raman-like RIXS excitations correspond to collective spin excitations, which are magnons in the undoped Mott insulators and evolve into paramagnons in doped superconducting compounds. In contrast, the fluorescence-like shifts are due primarily to the continuum of particle-hole excitations in the charge channel. Our results show that under the proper experimental conditions RIXS indeed can be used to probe paramagnons in doped high-T_c cuprate superconductors.

Characteristics of C6-7 myelopathy: assessment of clinical symptoms and electrophysiological findings

STUDY DESIGN

This is a single-center retrospective study.

OBJECTIVES

The objective of this study was to study the clinical symptoms and electrophysiological features of C6-7 myelopathy.

SETTING

This study was conducted at the Department of Orthopedic surgery, Yamaguchi University Graduate school of medicine, Japan.

METHODS

A total of 20 patients with cervical compressive myelopathy were determined by spinal cord-evoked potentials or a single level of obvious magnetic resonance imaging (MRI)-documented cervical spinal cord compression. Neurological examinations included manual muscle testing and investigation of deep tendon reflex, including Hoffmann sign, and of sensory disturbance areas. Motor-evoked potentials (MEPs), compound muscle action potentials (CMAPs) and F-wave were recorded from bilateral abductor digit minim and abductor halluces muscles. Central motor conduction time was calculated as follows: MEPs latency-(CMAPs latency+F latency-1)/2 (ms).

RESULTS

Eighteen patients (90%) had negative Hoffmann sign. Eight patients (40%) had no sensory disturbance in the upper limbs and 8 patients (40%) had no muscle weakness in the upper limbs. We determined that patients had cervical myelopathy when their central motor conduction time measured in abductor digit minim was longer than 6.76 ms (+2 s.d.). Using this definition, the sensitivity for myelopathy was 42.8%.

CONCLUSION

Patients with C6-7 myelopathy may lack clinical symptoms in their hands and central motor conduction time measured in abductor digit minim tended to be less prolonged, and it only showed symptoms in their lower limbs as gait disturbance. Surgeons should bear in mind the possibility of disorders of caudal C6-7 when they encounter patients with no or few symptoms in their hands and with leg weakness or numbness.

Structural and Chemical Analysis of the Zirconia–Veneering Ceramic Interface

The interfacial interaction of veneering ceramic with zirconia is still not fully understood. This study aimed to characterize morphologically and chemically the zirconia–veneering ceramic interface. Three zirconia-veneering conditions were investigated: 1) zirconia–veneering ceramic fired on sandblasted zirconia, 2) zirconia–veneering ceramic on as-sintered zirconia, and 3) alumina–veneering ceramic (lower coefficient of thermal expansion [CTE]) on as-sintered zirconia. Polished cross-sectioned ceramic–veneered zirconia specimens were examined using field emission gun scanning electron microscopy (Feg-SEM). In addition, argon-ion thinned zirconia–veneering ceramic interface cross sections were examined using scanning transmission electron microscopy (STEM)–energy dispersive X-ray spectrometry (EDS) at high resolution. Finally, the zirconia–veneering ceramic interface was quantitatively analyzed for tetragonal-to-monoclinic phase transformation and residual stress using micro-Raman spectroscopy (µRaman). Feg-SEM revealed tight interfaces for all 3 veneering conditions. High-resolution transmission electron microscopy (HRTEM) disclosed an approximately 1.0-µm transformed zone at sandblasted zirconia, in which distinct zirconia grains were no longer observable. Straight grain boundaries and angular grain corners were detected up to the interface of zirconia– and alumina–veneering ceramic with as-sintered zirconia. EDS mapping disclosed within the zirconia–veneering ceramic a few nanometers thick calcium/aluminum-rich layer, touching the as-sintered zirconia base, with an equally thick silicon-rich/aluminum-poor layer on top. µRaman revealed t-ZrO2-to- m-ZrO2 phase transformation and residual compressive stress at the sandblasted zirconia surface. The difference in CTE between zirconia– and the alumina–veneering ceramic resulted in residual tensile stress within the zirconia immediately adjacent to its interface with the veneering ceramic. The rather minor chemical elemental shifts recorded in the veneering ceramic did not suffice to draw definitive conclusions regarding potential chemical interaction of the veneering ceramic with zirconia. Sandblasting damaged the zirconia surface and induced phase transformation that also resulted in residual compressive stress. Difference in CTE of zirconia versus that of the veneering ceramic resulted in an unfavorable residual tensile stress at the zirconia–veneering ceramic interface.

Porosity dependency of an optimized stent design for an intracranial aneurysm

BACKGROUND

Optimal design of stents for a cerebral aneurysm is desired for efficient flow reduction in the aneurysm.

OBJECTIVE

In this study, we aimed to optimize stent design at several porosities, estimate the influence of stent design on aneurysm flow, and evaluate the ability of stents to reduce flow.

METHODS

Stent models were constructed as sets of squares or rectangles in the necks of a two-dimensional (2D) and realistic aneurysm. Then, automated optimization was performed using a combination of simulated annealing and lattice Boltzmann flow simulation.

RESULTS

By simulated annealing, stents were gradually modified to reduce the average velocity in an aneurysm. As a result of optimization, stents of all porosities demonstrated an inhomogeneous distribution with dense struts in the inflow area. Flow reduction was increased compared with the initial stent. Under the condition of high porosity, flow reduction by the stent drastically increased as porosity decreased. Under low porosity, the increase of velocity reduction was moderate even as porosity decreased.

CONCLUSIONS

Optimization can enhance flow reduction by stents. However, the increase in reduction associated with decreasing porosity is moderate under lower-porosity conditions. This threshold may help in the choice of stent porosity for each specific aneurysm.