Nanoscale defect evaluation framework combining real-time transmission electron microscopy and integrated machine learning-particle filter estimation

Observation of dynamic processes by transmission electron microscopy (TEM) is an attractive technique to experimentally analyze materials’ nanoscale phenomena and understand the microstructure-properties relationships in nanoscale. Even if spatial and temporal resolutions of real-time TEM increase significantly, it is still difficult to say that the researchers quantitatively evaluate the dynamic behavior of defects. Images in TEM video are a two-dimensional projection of three-dimensional space phenomena, thus missing information must be existed that makes image’s uniquely accurate interpretation challenging. Therefore, even though they are still a clustering high-dimensional data and can be compressed to two-dimensional, conventional statistical methods for analyzing images may not be powerful enough to track nanoscale behavior by removing various artifacts associated with experiment; and automated and unbiased processing tools for such big-data are becoming mission-critical to discover knowledge about unforeseen behavior. We have developed a method to quantitative image analysis framework to resolve these problems, in which machine learning and particle filter estimation are uniquely combined. The quantitative and automated measurement of the dislocation velocity in an Fe-31Mn-3Al-3Si autunitic steel subjected to the tensile deformation was performed to validate the framework, and an intermittent motion of the dislocations was quantitatively analyzed. The framework is successfully classifying, identifying and tracking nanoscale objects; these are not able to be accurately implemented by the conventional mean-path based analysis.

Performance Evaluation for Repair of HSGc-C5 Carcinoma Cell Using Geant4-DNA

Track-structure Monte Carlo simulations are useful tools to evaluate initial DNA damage induced by irradiation. In the previous study, we have developed a Gean4-DNA-based application to estimate the cell surviving fraction of V79 cells after irradiation, bridging the gap between the initial DNA damage and the DNA rejoining kinetics by means of the two-lesion kinetics (TLK) model. However, since the DNA repair performance depends on cell line, the same model parameters cannot be used for different cell lines. Thus, we extended the Geant4-DNA application with a TLK model for the evaluation of DNA damage repair performance in HSGc-C5 carcinoma cells which are typically used for evaluating proton/carbon radiation treatment effects. For this evaluation, we also performed experimental measurements for cell surviving fractions and DNA rejoining kinetics of the HSGc-C5 cells irradiated by 70 MeV protons at the cyclotron facility at the National Institutes for Quantum and Radiological Science and Technology (QST). Concerning fast- and slow-DNA rejoining, the TLK model parameters were adequately optimized with the simulated initial DNA damage. The optimized DNA rejoining speeds were reasonably agreed with the experimental DNA rejoining speeds. Using the optimized TLK model, the Geant4-DNA simulation is now able to predict cell survival and DNA-rejoining kinetics for HSGc-C5 cells.

Acetic-acid-induced jasmonate signaling in root enhances drought avoidance in rice

Conferring drought resistant traits to crops is one of the major aims of current breeding programs in response to global climate changes. We previously showed that exogenous application of acetic acid to roots of various plants could induce increased survivability under subsequent drought stress conditions, but details of the metabolism of exogenously applied acetic acid, and the nature of signals induced by its application, have not been unveiled. In this study, we show that rice rapidly induces jasmonate signaling upon application of acetic acid, resulting in physiological changes similar to those seen under drought. The major metabolite of the exogenously applied acetic acid in xylem sap was determined as glutamine-a common and abundant component of xylem sap-indicating that acetic acid is not the direct agent inducing the observed physiological responses in shoots. Expression of drought-responsive genes in shoot under subsequent drought conditions was attenuated by acetic acid treatment. These data suggest that acetic acid activates root-to-shoot jasmonate signals that partially overlap with those induced by drought, thereby conferring an acclimated state on shoots prior to subsequent drought.

Experimental study on monitoring system of clinical beam purity in multiple-ion beam operation for heavy-ion radiotherapy

The National Institute of Radiological Sciences has investigated multiple-ion therapy using energetic beams of helium, carbon, oxygen, and neon ions, to improve treatment outcomes of refractory cancer. For this therapy, it is necessary to ensure the helium-ion beam purity to avoid irradiation by unwanted ions. Here, we develop a measurement method for monitoring beam purity. This method can measure the charge number of the ions in a high-purity beam using an ionization chamber and Faraday cup. In addition, it can be used to detect the contamination of the clinical helium-ion beam. We perform beam experiments to evaluate our beam-purity monitoring method and predict that our method is capable of detecting contamination below 1%.

Effect of External Magnetic Fields on Biological Effectiveness of Proton Beams

PURPOSE

The purpose is to verify experimentally whether application of magnetic fields longitudinal and perpendicular to a proton beam alters the biological effectiveness of the radiation.

METHODS AND MATERIALS

Proton beams with linear energy transfer of 1.1 and 3.3 keV/μm irradiated human cancer and normal cells under a longitudinal (perpendicular) magnetic field of B_L (B_P) = 0, 0.3, or 0.6 T. Cell survival curves were constructed to evaluate the effects of the magnetic fields on the biological effectiveness. The ratio of dose that would result in a survival fraction of 10% without the magnetic field D_wo to the dose with the magnetic field D_w, R₁₀ = D_wo/D_w, was determined for each cell line and magnetic field.

RESULTS

For cancer cells exposed to the 1.1- (3.3-) keV/μm proton beams, R₁₀s were increased to 1.10 ± 0.07 (1.11 ± 0.07) and 1.11 ± 0.07 (1.12 ± 0.07) by the longitudinal magnetic fields of B_L = 0.3 and 0.6 T, respectively. For normal cells, R₁₀s were increased to 1.13 ± 0.06 (1.17 ± 0.06) and 1.17 ± 0.06 (1.30 ± 0.06) by the B_Ls. In contrast, R₁₀s were not changed significantly from 1 by the perpendicular magnetic fields of B_P = 0.3 and 0.6 T for both cancer and normal cells exposed to 1.1- and 3.3-keV/μm proton beams.

CONCLUSIONS

The biological effectiveness of proton beams was significantly enhanced by longitudinal magnetic fields of B_L = 0.3 and 0.6 T, whereas the biological effectiveness was not altered by perpendicular magnetic fields of the same strengths. This enhancement effect should be taken into account in magnetic resonance imaging guided proton therapy with a longitudinal magnetic field.

Effects of Magnetic Field Applied Just Before, During or Immediately after Carbon-Ion Beam Irradiation on its Biological Effectiveness

Previously reported studies have revealed that the application of a magnetic field longitudinal to a carbon-ion beam enhances its biological effectiveness. Here we investigated how timing of the magnetic field application with respect to beam irradiation influenced this effect. Human cancer cells were exposed to carbon-ion beams with linear energy transfer (LET) of 12 and 50 keV/µm. The longitudinal magnetic field of 0.3 T was applied to the cells just before, during or immediately after the beam irradiation. The effects of the timing on the biological effectiveness were evaluated by cell survival. The biological effectiveness increased only if the magnetic field was applied during beam irradiation for both LETs.

Influence of a perpendicular magnetic field on biological effectiveness of carbon-ion beams

Purpose: Our previous study revealed that the application of a magnetic field longitudinal to a carbon-ion beam of 0.1 ≤ B_//≤ 0.6 T enhances the biological effectiveness of the radiation. The purpose of this study is to experimentally verify whether the application of a magnetic field perpendicular to the beam also alters the biological effectiveness. Methods and materials: Most experimental conditions other than the magnetic field direction were the same as those used in the previous study to allow comparison of their results. Human cancer and normal cells were exposed to low (12 keV/μm) and high (50 keV/μm) linear energy transfer (LET) carbon-ion beams under the perpendicular magnetic fields of B⊥ = 0, 0.15, 0.3, or 0.6 T generated by a dipole magnet. The effects of the magnetic fields on the biological effectiveness were evaluated by clonogenic cell survival. Doses that would result in the survival of 10%, D₁₀s, were determined for the exposures and analyzed using Student's t-tests. Results: For both cancer and normal cells treated by low- and high-LET carbon-ion beams, the D₁₀s measured in the presence of the perpendicular magnetic fields of B⊥ ≥ 0.15 T were not statistically different (p ≫ .05) from the D₁₀s measured in the absence of the magnetic fields, B⊥ = 0 T. Conclusions: Exposure of human cancer and normal cells to the perpendicular magnetic fields of B⊥ ≤ 0.6 T did not alter significantly the biological effectiveness of the carbon-ion beams, unlike the exposure to longitudinal magnetic fields of the same strength. Although the mechanisms underlying the observed results still require further exploration, these findings indicate that the influence of the magnetic field on biological effectiveness of the carbon-ion beam depends on the applied field direction with respect to the beam.

Pathophysiological characteristics of non-alcoholic steatohepatitis-like changes in cholesterol-loaded type 2 diabetic rats

Spontaneously Diabetic Torii (SDT) fatty rats, a new obese diabetic model, reportedly presented with features of non-alcoholic steatohepatitis (NASH) after 32 weeks of age. We tried to accelerate the onset of NASH in SDT fatty rats using dietary cholesterol loading and noticed changes in the blood choline level which is expected to be a NASH biomarker. Body weight and biochemical parameters were measured from 8 to 24 weeks of age. At 16, 20, 24 weeks, pathophysiological analysis of the livers were performed. Hepatic lipids, lipid peroxides, and the expression of mRNA related to triglyceride (TG) synthesis, inflammation, and fibrosis were evaluated at 24 weeks. Hepatic fibrosis was observed in SDT fatty rats fed cholesterol-enriched diets (SDT fatty-Cho) from 16 weeks. Furthermore, hepatic lipids and lipid peroxide were significantly higher in SDT fatty-Cho than SDT fatty rats fed normal diets at 24 weeks. Hepatic mRNA expression related to TG secretion decreased in SDT fatty-Cho, and the mRNA expression related to inflammation and fibrosis increased in SDT fatty-Cho at 24 weeks. Furthermore, SDT fatty-Cho presented with increased plasma choline, similar to human NASH. There were no significant changes in the effects of feeding a cholesterol-enriched diet in Sprague-Dawley rats. SDT fatty-Cho has the potential to become a valuable animal model for NASH associated with type 2 diabetes and obesity.

Pathophysiological analysis of the progression of hepatic lesions in STAM mice

Nonalcoholic steatohepatitis (NASH) is a current health issue since the disease often leads to hepatocellular carcinoma; however, the pathogenesis of the disease has still not been fully elucidated. In this study, we investigated the pathophysiological changes observed in hepatic lesions in STAM mice, a novel NASH model. STAM mice, high fat-diet (HFD) fed mice, and streptozotocin (STZ) treated mice were prepared, and changes over time, such as biological parameters, mRNA expression, and histopathological findings, were evaluated once animal reached 5, 7, and 10 weeks of age. STZ mice presented with hyperglycemia and an increase in oxidative stress in immunohistochemical analyses of Hexanoyl-lysine: HEL from 5 weeks, with fibrosis in the liver also being observed from 5 weeks. HFD mice presented with hyperinsulinemia from 7 weeks and the slight hepatosteatosis was observed at 5 weeks, with changes significantly increasing until 10 weeks. STAM mice at 10 weeks showed significant hepatic changes, including hepatosteatosis, hypertrophic hepatocytes, and fibrosis, indicating pathological changes associated with NASH. These results suggested that the increase in oxidative stress with hyperglycemia triggered hepatic lesions in STAM mice, and insulin resistance promoted lesion formation with hepatic lipid accumulation. STAM mice may be a useful model for elucidating the pathogenesis of NASH with diabetes.

Association Between the Fertile Period and Live Birth Post-Kidney Transplantation: A Retrospective Single-Center Cohort Study

BACKGROUND

Despite restoration of fertility after kidney transplantation, the benefit is limited in female kidney recipients. Our objective is to determine the reasons for this discrepancy.

METHODS

We evaluated 315 women who underwent kidney transplantation from 1983 to 2015 (a median of age at transplantation [10th-90th percentile] of 32 years [7-55 years]); 230 recipients between the ages of 15 to 49 years old as of March 2016 were observed.

RESULTS

We experienced 10 abortions and 21 live births from our 23 recipients and 2 abortions and 7 live births in 7 recipients from other transplant center. The live birth rate was 8.9 per 1000 female transplant recipients of childbearing age. Seven recipients received either treatments of artificial insemination or in vitro fertilization. Average age at pregnancy was 33.2 ± 3.2 years old, and the fertile period post-transplantation was longer in recipients with live births than those without live births (14.1 ± 7.1 vs 9.9 ± 7.3 years, P < .05). In 42.9% of recipients with live birth, pregnancy-induced hypertension was observed in the last trimester. The gestational age and the average birth weight were 32.8 ± 5.0 months and 2184 ± 632 g, respectively. During follow-up of 14.5 years, there was one case of graft loss, which is a rate of 2.5 per 1000 female recipients.

CONCLUSION

Although pregnancy complications are often observed in kidney recipients, graft survival is less influenced by pregnancy. Importantly, kidney disease at childbearing age disrupts pregnancy even after kidney transplantation.

Pharmacokinetic Profile of Twice- and Once-daily Tacrolimus in Pediatric Kidney Transplant Recipients

BACKGROUND

The aim of this study was to assess the differences in pharmacokinetic (PK) profiles after the 1:1 ratio-based conversion from a twice-daily to a once-daily tacrolimus formulation (TD-TAC and OD-TAC, respectively) in pediatric recipients of kidney transplants.

METHODS

TD-TAC was initially administered to 29 pediatric patients who underwent kidney transplantations between April 2010 and September 2015 and were then subsequently switched to OD-TAC. The switch dose ratio was 1:1, and the 24-hour complete PK parameter assessment was performed before and after the regimen was changed from TD-TAC to OD-TAC.

RESULTS

The mean total daily dose at baseline was 5.5 ± 2.9 mg (0.18 ± 0.10 mg/kg body weight). Consecutive PK studies revealed no significant difference in the mean time to achieve maximum concentrations and the area under the concentration-time curve from 0 to 24 hours (AUC_0-24) of both drug formulations. However, the mean trough concentration (C_min) and the maximum concentration of OD-TAC were 22% and 6% lower and higher, respectively, than those of TD-TAC. Therefore, a better correlation was observed between the AUC_0-24 and C_min of OD-TAC than between those of TD-TAC.

CONCLUSIONS

After the change from TD-TAC to OD-TAC, the AUC_0-24 values were equivalent despite a 22% reduction in C_min. C_min may therefore be an excellent predictor in the therapeutic drug monitoring of OD-TAC because of its superior correlation with AUC_0-24.

Similar Anemic Control Between Chronic Kidney Diseases in Patients With and Without Transplantation on Entry to Dialysis

BACKGROUND

Transplant recipients are supposedly in a more anemic, catabolic, and even inflammatory state at re-entering hemodialysis due to chronic rejection. The goal of this study was to clarify how transplant recipients can re-enter dialysis safely by focusing on control of anemia.

METHODS

From 2012 to 2014, a total of 29 transplant recipients re-entered hemodialysis because of chronic rejection (ie, the chronic kidney disease with transplant [CKDT] group). At the same time, in 2014, a total of 30 patients with chronic kidney disease without transplantation entered dialysis as the control group (ie, the CKD group). CKDT recipients (mean ± standard deviation age, 41.9 ± 11.8 years; 18 male subjects, 10 female subjects; frequency of diabetes, 10%; duration of graft survival, 12.5 ± 4.3 years) were younger and fewer had diabetes compared with the CKD group (age, 53.2 ± 10.5 years; 21 male subjects, 9 female subjects; frequency of diabetes, 36%). Patient characteristics at entering dialysis in both groups were analyzed according to retrospective chart review.

RESULTS

At entering dialysis, there were no significant differences between the CKD and CKDT groups in terms of the following: dose of darbepoetin; concentrations of hemoglobin, albumin, and C-reactive protein; cardiothoracic ratio; blood urea nitrogen and creatinine levels; estimated glomerular filtration rate; initial ultrafiltration; and duration of hospitalization for initiation of dialysis. The only difference between groups was mean weight at entry to dialysis (CKDT group, 58.5 ± 15.1 kg; CKD group, 67.1 ± 14.8 kg; P = .03). The darbepoetin dose per kilogram of weight did not differ between groups (CKDT, 2.28 ± 2.03 μg/kg; CKD, 2.12 ± 1.6 μg/kg; P = .95) in the final month before entry to dialysis.

CONCLUSIONS

Safe re-initiation of dialysis is important for recipient survival. Although anemia is supposedly higher in transplant recipients due to immunosuppression, this single-center analysis found no difference in anemia in CKD with or without transplantation, caused by good use of erythropoietin-stimulating agents in both groups.

Overexpression of TIFY genes promotes plant growth in rice through jasmonate signaling

Because environmental stress can reduce crop growth and yield, the identification of genes that enhance agronomic traits is increasingly important. Previous screening of full-length cDNA overexpressing (FOX) rice lines revealed that OsTIFY11b, one of 20 TIFY proteins in rice, affects plant size, grain weight, and grain size. Therefore, we analyzed the effect of OsTIFY11b and nine other TIFY genes on the growth and yield of corresponding TIFY-FOX lines. Regardless of temperature, grain weight and culm length were enhanced in lines overexpressing TIFY11 subfamily genes, except OsTIFY11e. The TIFY-FOX plants exhibited increased floret number and reduced days to flowering, as well as reduced spikelet fertility, and OsTIFY10b, in particular, enhanced grain yield by minimizing decreases in fertility. We suggest that the enhanced growth of TIFY-transgenic rice is related to regulation of the jasmonate signaling pathway, as in Arabidopsis. Moreover, we discuss the potential application of TIFY overexpression for improving crop yield.

First results of the 2.45 GHz Oshima electron cyclotron resonance ion source

A new electron cyclotron resonance ion source has been constructed at Oshima College with a 2.45 GHz magnetron microwave source and permanent magnets employed as the main components. In addition, a solid-state power amplifier with a frequency range of 2.5-6.0 GHz was installed to study two-frequency plasma heating. Three solenoid coils were set up for adjusting the axial magnetic fields. Argon plasma generation and ion beam production have been conducted during the first year of operation. Ion current densities in the ECR plasma were measured using a biased disk. For 2.45 and 4.65 GHz two-frequency plasma heating, the ion density was approximately 1.5 times higher than that of 2.45 GHz single-frequency heating.

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.

Production of multicharged metal ion beams on the first stage of tandem-type ECRIS

Multicharged metal ion beams are required to be applied in a wide range of fields. We aim at synthesizing iron-endohedral fullerene by transporting iron ion beams from the first stage into the fullerene plasma in the second stage of the tandem-type electron cyclotron resonance ion source (ECRIS). We developed new evaporators by using a direct ohmic heating method and a radiation heating method from solid state pure metal materials. We investigate their properties in the test chamber and produce iron ions on the first stage of the tandem-type ECRIS. As a result, we were successful in extracting Fe(+) ion beams from the first stage and introducing Fe(+) ion beams to the second stage. We will try synthesizing iron-endohedral fullerene on the tandem-type ECRIS by using these evaporators.

Experimental results of superimposing 9.9 GHz extraordinary mode microwaves on 2.45 GHz ECRIS plasma

Efficient production of multicharged ions has been investigated on the tandem-type ECRIS in Osaka University. According to the consideration of the accessibility conditions of microwaves to resonance and cutoff regions, it was suggested that the upper hybrid resonance (UHR) heating contributed to enhancement of ion beam intensity. In order to enhance multicharged ion beams efficiently, injecting higher frequency microwave with extraordinary (X-mode) toward UHR region has been tried. In this study, 2.45 GHz frequency microwaves are used for conventional ECR discharge, and 9.9 GHz frequency microwaves with X-mode are superimposed for UHR heating. The effects of additive microwave injection are investigated experimentally in terms of plasma parameters and electron energy distribution function (EEDF) measured by Langmuir probe and ion beam current. As the results show, it is confirmed that the electrons in the high energy region are affected by 9.9 GHz X-mode microwave injection from the detailed analysis of EEDF.

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.

A singly charged ion source for radioactive ¹¹C ion acceleration

A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive (11)C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

Producing multicharged fullerene ion beam extracted from the second stage of tandem-type ECRIS

We have been constructing the tandem-type electron cyclotron resonance ion source (ECRIS). Two ion sources of the tandem-type ECRIS are possible to generate plasma individually, and they also confined individual ion species by each different plasma parameter. Hence, it is considered to be suitable for new materials production. As the first step, we try to produce and extract multicharged C60 ions by supplying pure C60 vapor in the second stage plasma because our main target is producing the endohedral fullerenes. We developed a new evaporator to supply fullerene vapor, and we succeeded in observation about multicharged C60 ion beam in tandem-type ECRIS for the first time.

Comparison of plant-type phosphoenolpyruvate carboxylases from rice: identification of two plant-specific regulatory regions of the allosteric enzyme

Phosphoenolpyruvate carboxylase (PEPC) is a key enzyme of primary metabolism in bacteria, algae and vascular plants, and it undergoes allosteric regulation by various metabolic effectors. Rice (Oryza sativa) has five plant-type PEPCs, four cytosolic and one chloroplastic. We investigated their kinetic properties using recombinant proteins and found that, like most plant-type PEPCs, rice cytosolic isozymes were activated by glucose 6-phosphate and by alkaline pH. In contrast, no such activation was observed for the chloroplastic isozyme, Osppc4. In addition, Osppc4 showed low affinity for the substrate phosphoenolpyruvate (PEP) and very low sensitivities to allosteric inhibitors aspartate and glutamate. By comparing the isozyme amino acid sequences and three-dimensional structures simulated on the basis of the reported crystal structures, we identified two regions where Osppc4 has unique features that can be expected to affect its kinetic properties. One is the N-terminal extension; replacement of the extension of Osppc2a (cytosolic) with that from Osppc4 reduced the aspartate and glutamate sensitivities to about one-tenth of the wild-type values but left the PEP affinity unaffected. The other is the N-terminal loop, in which a conserved lysine at the N-terminal end is replaced with a glutamate-alanine pair in Osppc4. Replacement of the lysine of Osppc2a with glutamate-alanine lowered the PEP affinity to a quarter of the wild-type level (down to the Osppc4 level), without affecting inhibitor sensitivity. Both the N-terminal extension and the N-terminal loop are specific to plant-type PEPCs, suggesting that plant-type isozymes acquired these regions so that their activity could be regulated properly at the sites where they function.

Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron

The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C(4+) ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C(4+), for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.

Operation status of the electron cyclotron resonance ion source at Gunma University

An ECR ion source of Gunma University Heavy Ion Medical Center, so-called KeiGM [M. Muramatsu, A. Kitagawa, Y. Sakamoto, S. Sato, Y. Sato, H. Ogawa, S. Yamada, H. Ogawa, Y. Yoshida, and A. G. Drentje, Rev. Sci. Instrum. 76, 113304 (2005)], has been operated for cancer therapy and physical/biological experiment since 2010. KeiGM produces typically 230 μA of 10 keV/u C(4+) ions from CH4 gases. The vacuum pressure is kept between 1.2 × 10(-4) and 1.7 × 10(-4) Pa so as to suppress the pulse-to-pulse current fluctuation within ±10%. The extraction electrode is cleaned every 6-8 months in order to remove deposited carbon, which increases the leak current and discharge. In order to investigate the possibility of long-term operation without such maintenances, oxygen aging for the cleaning of the extraction electrode has been tested in the test bench. The same-designed ion sources at National Institute of Radiological Sciences and SAGA Heavy Ion Medical Accelerator in Tosu (SAGA-HIMAT) are also operated with stable C(4+) current, which are suitable for the continuous operation for cancer therapy.

Synthesis of endohedral iron-fullerenes by ion implantation

In this paper, we discuss the results of our study of the synthesis of endohedral iron-fullerenes. A low energy Fe(+) ion beam was irradiated to C60 thin film by using a deceleration system. Fe(+)-irradiated C60 thin film was analyzed by high performance liquid chromatography and laser desorption/ ionization time-of-flight mass spectrometry. We investigated the performance of the deceleration system for using a Fe(+) beam with low energy. In addition, we attempted to isolate the synthesized material from a Fe(+)-irradiated C60 thin film by high performance liquid chromatography.

A study on prevention of an electric discharge at an extraction electrode of an electron cyclotron resonance ion source for cancer therapy

A compact ECR ion source has utilized for carbon radiotherapy. In order to increase beam intensity with higher electric field at the extraction electrode and be better ion supply stability for long periods, electric geometry and surface conditions of an extraction electrode have been studied. Focusing attention on black deposited substances on the extraction electrode, which were observed around the extraction electrode after long-term use, the relation between black deposited substances and the electrical insulation property is investigated. The black deposited substances were inspected for the thickness of deposit, surface roughness, structural arrangement examined using Raman spectroscopy, and characteristics of electric discharge in a test bench, which was set up to simulate the ECR ion source.

(11)CH4 molecule production using a NaBH4 target for (11)C ion acceleration

Solid-state materials suitable for use as proton irradiation targets were investigated for producing high-purity (11)CH4 molecules for heavy-ion cancer therapy. The radioactivity of gas produced by proton irradiation was measured for several target materials. Also, the radioactive molecular species of the produced gas were analyzed by radio gas chromatography. We found that 5 × 10(12) (11)C molecules could be collected by proton irradiation on a NaBH4 target. We also found that the (11)CH4 molecules were produced and collected directly from the irradiated target, owing to the hydrogen atoms bound in the solid-state NaBH4.

Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide band-width (17.1-18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1-18.5 GHz), and the effect of this frequency on the HCI-production rate was examined under several operation conditions. As an overall result, new beam records of highly charged argon, krypton, and xenon beams were obtained at the NIRS-HEC ion source by this high-power two-frequency operation mode.

Status of the Bio-Nano electron cyclotron resonance ion source at Toyo University

In the paper, the material science experiments, carried out recently using the Bio-Nano electron cyclotron resonance ion source (ECRIS) at Toyo University, are reported. We have investigated several methods to synthesize endohedral C60 using ion-ion and ion-molecule collision reaction in the ECRIS. Because of the simplicity of the configuration, we can install a large choice of additional equipment in the ECRIS. The Bio-Nano ECRIS is suitable not only to test the materials production but also to test technical developments to improve or understand the performance of an ECRIS.

Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source

A synthesis technology of endohedral fullerenes such as Fe@C60 has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C60 was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction.

Thigh muscularity and strength in teenage soccer players

This study examined the thigh muscularity and strength capability in early adolescent soccer players. The cross-sectional areas (CSAs) of the thigh muscles and dynamic strength during knee extension and flexion at 1.05 rad/s were determined twice at an interval of 6 months in 24 male soccer players aged 12-13 years and 11 age- and body height-matched non-athletes. After 6 months, muscle CSA and dynamic strength increased without significant interaction of time and group. Thigh total muscle CSA was not significantly affected by group, but the value relative to either thigh CSA or body mass was higher in soccer players. While knee flexion strength was similar between the 2 groups, knee extension strength was greater in soccer players than in non-athletes, even in terms of strength relative to CSA. The current results indicate that, compared with age- and body height-matched non-athletes, early adolescent soccer players are characterized by higher relative distribution of muscle mass within the thigh and higher knee extension strength relative to the quadriceps CSA. During the growth stage in which body height begins to increase markedly, however, participation in competitive soccer training does not increase the rate of development in thigh muscularity and strength.

Perceived chewing ability and need for long-term care in the elderly: a 5-year follow-up study

Increasing need for long-term care in older adults is expected with the ageing of Japan's population. The aim of the present study was to show the relationship between perceived chewing ability and long-term care needs for over 5 years in elderly persons. The chewing ability of 812 elderly persons living independently was evaluated at baseline using self-assessed masticatory ability, and it was classified into one of three categories: ability to chew all foods (good masticatory ability), ability to chew only slightly hard food (fair masticatory ability), and ability to only chew soft or pureed food (poor masticatory ability). Participants' care needs were then followed through Japan's long-term care insurance system for over 5 years. The log-rank test and Cox proportional hazard model were used to examine statistical differences in the frequency of care-needs certification between participants with good and fair or poor masticatory ability. Among participants aged 65-79 years, the frequency of care-needs certification was significantly higher in those with fair or poor masticatory ability than in those with good masticatory ability, and the relative hazard ratio was significantly higher in those with fair or poor masticatory ability than in those with good masticatory ability, after adjusting for age, gender, current employment status, educational background, social interaction, chronic medical conditions and dentition status. These relationships were not found among those aged 80-93 years. Impairment in perceived chewing ability may be associated with higher incidence of certification in Japan's long-term care insurance system among elderly persons aged 65-79.

Factors associated with self-assessed masticatory ability among community-dwelling elderly Japanese

Self-assessed masticatory ability has been shown to be significantly related to general health among elderly persons.

OBJECTIVE

To identify oral factors associated with the self-assessed masticatory ability.

BASIC RESEARCH DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 736 community-dwelling elderly persons.

MAIN OUTCOME MEASURES

Data on background factors and the self-assessed masticatory ability were collected by questionnaire. An intraoral examination examined the pattern of posterior occluding pairs of natural teeth (POPs), the WHO Community Periodontal Index of Treatment Needs (CPI) and denture-related factors such as use of dentures, pain when using dentures and stability and retention of dentures. Chi-squared tests examined the relationships between the self-assessed masticatory ability and the background factors and oral conditions. Ordinal regression models were constructed with the self-assessed masticatory ability as the dependent variable and oral conditions as the principal independent variables, to adjust for the potential confounding variables.

RESULTS

Self-assessed impairment of masticatory ability was associated with lost POPs (p < 0.001) and CPI (p = 0.012). In the participants with lost POPs, self-assessed impairment of masticatory ability was associated with not using dentures and pain when using dentures (p < 0.001). In the totally edentulous subjects, impairment of masticatory ability was not associated with stability and retention of dentures (p = 0.070).

CONCLUSIONS

Factors affecting self-assessed masticatory ability include the pattern of POPs, periodontal status, denture use and pain when using dentures.

Low energy Fe+ beam irradiation to C60 thin film

We have developed an electron cyclotron resonance ion source apparatus, which is designed for the production of endohedral fullerene. In this study, we irradiated the Fe(+) beam to the C(60) thin film. We changed the experimental condition of the dose and the ion energy. We could observe the Fe + C(60) peak by analysis of the time-of-flight mass spectrometry. The highest intensity of the Fe + C(60) peak was observed at the ion energy of 200 eV. The Fe + C(60) peak intensity tended to become high in the case of long irradiation time and large dose.

A review of ion sources for medical accelerators (invited)

There are two major medical applications of ion accelerators. One is a production of short-lived isotopes for radionuclide imaging with positron emission tomography and single photon emission computer tomography. Generally, a combination of a source for negative ions (usually H- and/or D-) and a cyclotron is used; this system is well established and distributed over the world. Other important medical application is charged-particle radiotherapy, where the accelerated ion beam itself is being used for patient treatment. Two distinctly different methods are being applied: either with protons or with heavy-ions (mostly carbon ions). Proton radiotherapy for deep-seated tumors has become widespread since the 1990s. The energy and intensity are typically over 200 MeV and several 10(10) pps, respectively. Cyclotrons as well as synchrotrons are utilized. The ion source for the cyclotron is generally similar to the type for production of radioisotopes. For a synchrotron, one applies a positive ion source in combination with an injector linac. Carbon ion radiotherapy awakens a worldwide interest. About 6000 cancer patients have already been treated with carbon beams from the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan. These clinical results have clearly verified the advantages of carbon ions. Heidelberg Ion Therapy Center and Gunma University Heavy Ion Medical Center have been successfully launched. Several new facilities are under commissioning or construction. The beam energy is adjusted to the depth of tumors. It is usually between 140 and 430 MeV∕u. Although the beam intensity depends on the irradiation method, it is typically several 10(8) or 10(9) pps. Synchrotrons are only utilized for carbon ion radiotherapy. An ECR ion source supplies multi-charged carbon ions for this requirement. Some other medical applications with ion beams attract developer's interests. For example, the several types of accelerators are under development for the boron neutron capture therapy. This treatment is conventionally demonstrated by a nuclear reactor, but it is strongly expected to replace the reactor by the accelerator. We report status of ion source for medical application and such scope for further developments.

Effect of pulse-modulated microwaves on fullerene ion production with electron cyclotron resonance ion source

Fullerene plasmas generated by pulse-modulated microwaves have been investigated under typical conditions at the Bio-Nano electron cyclotron resonance ion source. The effect of the pulse modulation is distinct from that of simply structured gases, and then the density of the fullerene plasmas increased as decreasing the duty ratio. The density for a pulse width of 10 μs at the period of 100 μs is 1.34 times higher than that for CW mode. We have studied the responses of fullerene and argon plasmas to pulsed microwaves. After the turnoff of microwave power, fullerene plasmas lasted ∼30 times longer than argon plasmas.

Improvement of efficiency and temperature control of induction heating vapor source on electron cyclotron resonance ion source

An electron cyclotron resonance ion source (ECRIS) is used to generate multicharged ions for many kinds of the fields. We have developed an evaporator by using induction heating method that can generate pure vapor from solid state materials in ECRIS. We develop the new matching and protecting circuit by which we can precisely control the temperature of the induction heating evaporator. We can control the temperature within ±15 °C around 1400 °C under the operation pressure about 10(-4) Pa. We are able to use this evaporator for experiment of synthesizing process to need pure vapor under enough low pressure, e.g., experiment of generation of endohedral Fe-fullerene at the ECRIS.

Status of ion sources at National Institute of Radiological Sciences

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.

Study on the beam transport from the Bio-Nano ECRIS

The beam transport of N(+) ion and C(60)(+) ion in the Bio-Nano ECRIS with min-B configuration was investigated based on the ion beam profiles. The N(+) beam could be focused under the low-beam current conditions. Also the C(60)(+) beam could be focused in spite of the large space-charge effect which will lead the divergence of the beam. We confirmed that our beam transport system works well even for the C(60)(+) ion beam. We estimated the highest C(60)(+) beam current with the focused beam profile by comparing the N(+) ion beam.

Overexpression of a rice TIFY gene increases grain size through enhanced accumulation of carbohydrates in the stem

Screening of rice full-length cDNA overexpressing (FOX) lines allowed the identification of a TIFY gene, TIFY11b, as a growth-promoting gene whose overexpression increased plant height and seed size. The grains of TIFY11b-overexpressing plants exceeded those of non-transformants in length, width and thickness, resulting in 9-21% increases in grain weight. The increase was achieved by overexpressing the gene in the whole plant body, but not by seed-restricted expression, indicating that seed enlargement is attributable to overexpression in vegetative organs such as the leaf. The whole-body overexpressing plants developed longer leaves along with higher levels of starch and sucrose in the leaf sheath and culm at the heading stage than the non-transformants. Although overexpression of TIFY11b did not alter the photosynthetic rate per leaf area before and after heading, it caused an accumulation of higher levels of the carbohydrate assimilate, probably due to increased photosynthesis per plant, suggesting that the increase in grain size and weight is attained by enhanced accumulation and translocation of the carbohydrate in the culms and leaf sheaths of the transgenic plants. Thus, TIFY11b is a novel grain-size increasing gene.

Acclimation to high-light conditions in cyanobacteria: from gene expression to physiological responses

Photosynthetic organisms have evolved various acclimatory responses to high-light (HL) conditions to maintain a balance between energy supply (light harvesting and electron transport) and consumption (cellular metabolism) and to protect the photosynthetic apparatus from photodamage. The molecular mechanism of HL acclimation has been extensively studied in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Whole genome DNA microarray analyses have revealed that the change in gene expression profile under HL is closely correlated with subsequent acclimatory responses such as (1) acceleration in the rate of photosystem II turnover, (2) downregulation of light harvesting capacity, (3) development of a protection mechanism for the photosystems against excess light energy, (4) upregulation of general protection mechanism components, and (5) regulation of carbon and nitrogen assimilation. In this review article, we survey recent progress in the understanding of the molecular mechanisms of these acclimatory responses in Synechocystis sp. PCC 6803. We also briefly describe attempts to understand HL acclimation in various cyanobacterial species in their natural environments.

The combined impact of 12 common variants on hypertension in Japanese men, considering GWAS results

Genome-wide association studies have identified several polymorphisms that appear to be on hypertension-susceptible regions. We performed the current replication study in order to evaluate the association of these loci with hypertension in healthy Japanese males and then examined the combined effect of 12 independent variants. Overall, 735 Japanese men from two independent cohorts were recruited. Association with hypertension was assessed in 16 polymorphisms on 12 genes and 12 were chosen to evaluate the combined impact. Polymorphisms on the COMT, ATP2B1, CYP11A1 and the CSK genes were confirmed to be associated with hypertension and blood pressure (BP). Current findings also replicated previous results for the CYP11B2 and PTGIS genes. Although there were no significant associations found for other variants, our results suggested there was a combined impact for 12 loci. Individuals carrying more risk alleles had a higher risk of hypertension (P for the slope=0.002). Blood pressures also increased in conjunction with an increasing risk allele score (P for trend=7.84 × 10(-6) and 1.85 × 10(-5) for SBP and DBP, respectively). Our results confirmed the associations between hypertension or blood pressure and four gene variants. We also found a significant combined effect of the 12 gene loci.

Associations between self-assessed masticatory ability and higher brain function among the elderly

Among the elderly, the quality of higher brain function is a contributing factor in performing activities of daily living. The aim of the study is to elucidate, epidemiologically, associations between mastication and higher brain function. A total of 208 community-dwelling elderly persons, aged 70-74 years, were enrolled. Self-assessed masticatory ability (masticatory ability) was classified into one of three categories: ability to chew all kinds of food, ability to chew only slightly hard food, or ability to chew only soft or pureed food. Brain function was assessed by four neuropsychological tests: Raven's Colored Progressive Matrices (RCPM) test, the Verbal Paired Associates 1 (VerPA) task and the Visual Paired Associates 1 task (from the Wechsler Memory Scale Revised Edition), and the Block Design subtest (from the Wechsler Adult Intelligence Scales-Third Edition). Correlations between masticatory ability and each test were examined using Spearman rank correlation coefficients. Multinominal logistic regression models were conducted with the neuropsychological tests as the dependent variables and masticatory ability as the principal independent variable to adjust for age, gender, educational background, social activity, drinking/smoking habits, chronic medical conditions and dental status. Significant correlations were found between the RCPM test, the VerPA task, the Block Design test and masticatory ability. In multinominal logistic regression models, poor masticatory ability was significantly and independently related to the categories under the mean-s.d. points compared with those of the mean ± s.d. ranges for RCPM test and the VerPA task. Significant associations may exist between mastication and higher brain function among the elderly.

Contribution of trunk muscularity on sprint run

This study aimed to investigate how the trunk muscularity is related to sprint running performance. In 23 youth soccer players, the cross-sectional images at the mid level of each of L1-L2, L2-L3, L3-L4, L4-L5, and L5-S1 were obtained using magnetic resonance imaging to determine the cross-sectional areas (CSAs) of rectus abdominis, oblique, psoas major, quadratus lumborum and erector spinae muscles. The times taken to sprint over 20 m were measured, and the mean velocity of running was calculated for each of the 2 distances (V (10 m) and V (20 m)) and for the distance from 10 m to 20 m (V (10-20 m)). The CSA values of the 5 slice levels for all muscles except for the quadratus lumborum and those of the 3 slice levels (L1-L2, L2-L3 and L3-L4) for the quadratus lumborum were averaged and expressed relative to the two-third power of body mass (CSA/BM (2/3)). The CSA/BM (2/3) values of the erector spinae and quadratus lumborum were selected as significant contributors to predict V (10 m) ( R(2)=0.450), V (20 m) ( R(2)=0.504) and V (10-20 m) ( R(2)=0.420). The current results indicate that the muscularity of the erector spinae and quadratus lumborum contributes to achieving a high performance in sprint running over distances of less than 20 m.