Search

A new subassembly type passive reactor shutdown device is proposed to expand the diversity and robustness of core disruptive accident prevention measures for sodium-cooled fast reactors (SFRs). The device contains pins with a fuel material that is in a solid state during normal operation but melts and fluidizes during an unprotected loss of flow (ULOF) or unprotected transient overpower (UTOP) accident. By rapidly transferring the liquefied device fuel into the lower plenum region of the pins via gravitation alone, the device passively provides high negative reactivity to the core. This study evaluated the nuclear and thermal properties of the device subassembly with metallic fuel to determine the device specifications for proper device operation during ULOF and UTOP accidents. The results of the transient analysis of the ULOF initiating phase in a 750-MWel-class mixed-oxide-fueled SFR core confirmed that a conventional homogeneous core maintains stable cooling of the core before coolant boiling in the driver fuel subassemblies. In contrast, the negative reactivity required to terminate the event by device operation was slightly higher in the low sodium void reactivity core than in the conventional homogeneous core.

Following the Fukushima Nuclear Power Plant accident in 2011, it has become increasingly important for reactor safety designs to consider measures that can prevent the occurrence of severe accidents. This report proposes a novel subassembly-type passive reactor shutdown device that expands the diversity and robustness of core disruptive accident (CDA) prevention strategies for sodium-cooled fast reactors. The developed device contains pins with a fuel material that is in the solid state during normal operation but melts into a liquid when the temperature exceeds a certain value (i.e., during a potential accident). When an unprotected loss of flow (ULOF) or unprotected transient overpower (UTOP) accident occurs, the device can passively provide significant negative reactivity by rapidly transferring liquefied device fuel into the lower plenum region of the pins via gravitation alone. The reactors containing some of the proposed devices in place of original fuel subassemblies become subcritical before the driver fuels are damaged, even if ULOF or UTOP transient events occur. The present study evaluates candidate materials for device fuels (e.g., metallic alloy, chloride), optimal device pin structures for liquefied fuel relocation, and nuclear and thermal-hydraulic characteristics of the device-loaded core under accident conditions to demonstrate the engineering applicability of the proposed device. This report discusses preliminary results regarding the nuclear requirements for inducing negative reactivity to achieve reactor shutdown under the expected device conditions during an accident.

A new subassembly-type passive reactor shutdown device is proposed to expand the diversity and robustness of core disruptive accident prevention measures for sodium-cooled fast reactors (SFRs). The device contains pins with a fuel material that is in a solid state during normal operation but melts and fluidizes during an unprotected loss of flow (ULOF) or unprotected transient overpower (UTOP) accident. By rapidly transferring the liquefied device fuel into the lower plenum region of the pins via gravitation alone, the device can passively provide a large negative reactivity to the core. In this study, the nuclear and thermal properties of the device subassembly with metallic fuel were evaluated to determine the basic device specifications for proper device operation during ULOF and UTOP accidents. The results of the transient analysis of the ULOF initiating phase in a 750-MWe-class MOX-fueled SFR core showed that a conventional homogeneous core can maintain stable cooling of the core prior to coolant boiling in the driver fuel subassemblies. On the other hand, the negative reactivity required to terminate the event by device operation was found to be slightly larger in the low sodium void reactivity core than in the conventional homogeneous core.

In a severe accident of a nuclear power reactor, coolant channel blockage by solidified molten core debris may significantly influence the core degradations that follow. The moving particle semi-implicit (MPS) method is one of the Lagrangian-based particle methods for analyzing incompressible flows. In the study described in this paper, a novel solidification model for analyzing melt flowing channel blockage with the MPS method has been developed, which is suitable to attain a sufficient numerical accuracy with a reasonable calculation cost. The prompt velocity diffusion by viscosity is prioritized over the prompt velocity correction by the pressure term (for assuring incompressibility) within each time step over the “mushy zone” (between the solidus and liquidus temperature) for accurate modeling of solidification before fixing the coordinates of the completely solidified particles. To sustain the numerical accuracy and stability, the corrective matrix and particle shifting techniques have been applied to correct the discretization errors from irregular particle arrangements and to recover the regular particle arrangements, respectively. To validate the newly developed algorithm, 2-D benchmark analyses are conducted for steady-state freezing of the water in a laminar flow between two parallel plates. Furthermore, 3-D channel blockage analyses of a boiling water reactor (BWR) fuel support piece have been performed. The results show that a partial channel blockage develops from the vicinity of the speed limiter, which does not fully develop into a complete channel blockage, but still diverts the incoming melt flow that follows to the orifice region.

In order to clarify the cesium iodide (CsI) transport behavior with a focus on the mechanisms of gaseous iodine formation in the reactor coolant system of light water reactor (LWR) under a severe accident condition, a reproductive experiment of CsI transport behavior was conducted using a facility equipped with a thermal gradient tube. Various analyses on deposits and airborne materials during transportation could elucidate two mechanisms for the gaseous iodine formation. One was the gaseous phase chemical reaction in Cs-I-O-H system at relatively high-temperature region, which led to gaseous iodine transport to the lower temperature region without any further changes in gas species due to the kinetics limitation effects. The other one was the chemical reactions related to condensed phase of CsI, namely those of CsI deposits on walls with surface of stainless steel to form Cs2CrO4 compound and CsI aerosol particles with steam, which were newly found in this study.

After the Fukushima NPP accident in 2011, it has become increasingly important for reactor safety design to consider design measures to prevent the occurrence of severe accidents. In this study, a new subassembly-type passive reactor shutdown device is proposed to enhance the diversity and robustness of prevention measures for core disruptive accidents in sodium-cooled fast reactors. The proposed device contains pins with a fuel material that is kept in the solid state during normal operation but melts into the liquid when its temperature exceeds a prescribed value under the accidents. When a ULOF (unprotected loss of flow) or UTOP (unprotected transient overpower) accident occurs, the device can provide large negative reactivity passively by the relocation of liquefied device fuel into the lower plenum region of the pins by gravitation alone in a short time. The reactor, in which part of usual fuel subassemblies is replaced with the proposed devices, becomes subcritical before driver fuels are damaged, even if ULOF or UTOP transient occurs. In the present study, candidate materials for device fuel such as metallic alloy and chloride, optimum device pin structure for liquefied fuel relocation, and nuclear and thermal-hydraulic characteristics of the device-loaded core under accident conditions will be mainly investigated to demonstrate engineering feasibility of the proposed device. This paper describes the project overview and discusses preliminary results on nuclear requirements for negative reactivity to be inserted for reactor shutdown under expected device conditions.

Data on the clinical effectiveness of the novel anti-influenza drug baloxavir marboxil (baloxavir) in children remain limited. We conducted an observational study to compare the duration of fever and symptoms between baloxavir- and oseltamivir-treated children infected with influenza A and B. In total, 159 outpatients with influenza A(H1N1)pdm09 or B/Victoria-lineage infections, aged19 years, during the 2019-2020 influenza season in Japan were enrolled and assessed the duration of fever and symptoms using the Kaplan-Meier method and a multivariate Cox proportional hazard regression model. Polymerase acidic (PA) variants were examined before and after baloxavir treatment. In the multivariable analysis, the duration of fever and symptoms was unaltered between the A(H1N1)pdm09 (n = 116) and B/Victoria-lineage (n = 43) groups. Conversely, the fever duration was marginally longer in the oseltamivir-treated group (n = 59) than in the baloxavir group (n = 100) (hazard ratio (HR) = 0.67, p = 0.05); however, the duration of symptoms was unaltered between the two groups (HR = 0.74, p = 0.11). No patient presented PA reduced susceptibility marker(s) before baloxavir treatment in the analyzed groups. The PA/E23K variant was detected in one case (1.5%, 1/66) of A(H1N1)pdm09 after baloxavir treatment. One case (2.0%, 1/50) of A(H1N1)pdm09 with an N295S substitution in neuraminidase was detected following oseltamivir treatment. These results suggested that the duration of fever was likely to be shorter with baloxavir than with oseltamivir, but the difference between influenza A (H1N1)pdm09 and B/Victoria-lineage was unclear. It is important to continue evaluating the clinical effectiveness of baloxavir and monitoring its drug susceptibility to the influenza virus.

Aims Although shortening of the corrected QT interval (QTc) is a key finding in the diagnosis of short QT syndrome (SQTS), there may be overlap of the QTc between SQTS patients and normal subjects in childhood and adolescence. We aimed to investigate electrocardiographic findings for differentiation of SQTS patients. Methods and results The SQTS group comprised 34 SQTS patients Conclusion A QTcB

In order to improve LWR source term under severe accident conditions, the first version of a fission product chemistry database named ‘ECUME’ was developed. The ECUME is intended to include several...

Perinatal immunization education is important for improving the immunization outcomes of infants; however, the content of educational materials used at each perinatal period has not been carefully evaluated. We hypothesized that stepwise education offered at different perinatal periods would improve infant immunization status and enhance maternal immunization knowledge.In this cluster-randomized controlled trial, pregnant women were recruited from nine obstetric sites in Niigata, Japan. The intervention group received a stepwise, interactive education intervention (prenatally, postnatally, and 1month after birth). The control group received a leaflet containing general information on immunization. Infant immunization status was evaluated at 6months of age, and maternal immunization knowledge was evaluated by a written survey after each intervention.Among 188 study participants, 151 (80.3%) replied to the final post-intervention survey. At 6months of age, the percentage of children who completed three doses of inactivated polio, diphtheria, tetanus toxoid, and acellular pertussis (DTaP-IPV) vaccine was higher in the intervention group than in the control (p=0.04); however, no differences between groups were observed for the Haemophilus influenzae type b (Hib) (p=0.67) or 13-valent pneumococcal conjugate (PCV13) vaccines (p=0.20). The duration to the completion of the third dose of the DTaP-IPV, Hib, and PCV13 vaccines was shorter in the intervention group than in the control (p=0.03, p0.01, and p0.01, respectively). Furthermore, maternal knowledge scores exhibited significantly greater improvement in the intervention group over time compared with those of the control group (p=0.02).Stepwise perinatal immunization education improved immunization schedule adherence for required vaccines and improved maternal immunization knowledge.

Baloxavir marboxil has been used for influenza treatment since March 2018 in Japan. After baloxavir treatment, the most frequently detected substitution is Ile38Thr in polymerase acidic protein (PA/I38T), and this substitution reduces baloxavir susceptibility in influenza A viruses. To rapidly investigate the frequency of PA/I38T in influenza A (H1N1)pdm09 and A (H3N2) viruses in clinical samples, we established a rapid real-time system to detect single nucleotide polymorphisms in PA, using cycling probe real-time PCR. We designed two sets of probes that were labeled with either 6-carboxyfluorescein (FAM) or 6-carboxy-X-rhodamine (ROX) to identify PA/I38 (wild type strain) or PA/I38T, respectively. The established cycling probe real-time PCR system showed a dynamic linear range of 101 to 106 copies with high sensitivity in plasmid DNA controls. This real-time PCR system discriminated between PA/I38T and wild type viruses well. During the 2018/19 season, 377 influenza A-positive clinical samples were collected in Japan before antiviral treatment. Using our cycling probe real-time PCR system, we detected no (0/129, 0.0%) influenza A (H1N1)pdm09 viruses with PA/I38T substitutions and four A (H3N2) (4/229, 1.7%) with PA/I38T substitution prior to treatment. In addition, we found PA/I38T variant in siblings who did not received baloxavir treatment during an infection caused by A (H3N2) that afflicted the entire family. Although human-to-human transmission of PA/I38T variant may have occurred in a closed environment, the prevalence of this variant in influenza A viruses was still limited. Our cycling probe-PCR system is thus useful for antiviral surveillance of influenza A viruses possessing PA/I38T.

We report five cases of community- and hospital-acquired infections with oseltamivir- and peramivir-resistant A(H1N1)pdm09 viruses possessing the neuraminidase (NA) H275Y mutation during January–February 2016 in Japan. One case was hospitalized and was receiving oseltamivir for prophylaxis. The remaining four cases were not taking antiviral drugs at the time of sampling. These cases were geographically distant and epidemiologically unrelated. The five viruses showed ~300-fold rise in IC50 values against oseltamivir and peramivir, defined as highly reduced inhibition according to the WHO definition. Overall, the prevalence of the H275Y A(H1N1)pdm09 viruses was 1.8 % (5/282). The resistant viruses possessed the V241I, N369 K, and N386 K substitutions in the NA that have been previously reported among A(H1N1)pdm09 to alter transmission fitness. Analysis of Michaelis constant (Km) revealed that two of the isolates had reduced NA affinity to MUNANA, while the other three isolates displayed a slightly decreased affinity compared to the sensitive viruses. Further studies are needed to monitor the community spread of resistant viruses and to assess their transmissibility. Electronic supplementary material The online version of this article (doi:10.1007/s11262-016-1396-9) contains supplementary material, which is available to authorized users.

Transport behavior of CsI in the heating test, which simulated a BWR severe accident, was investigated by hard X-ray photoelectron spectroscopy (HAXPES) with an emphasis on the chemical effect of boron vapors. CsI deposited on metal tube at temperatures ranging from 150 °C to 750 °C was reacted with vapor/aerosol B 2 O 3 , and the chemical form of reaction products on the sample surface was examined from the HAXPES spectra of core levels, e.g., Ni 2p, Cs 3d and I 3d levels, and valence band. For the samples at ∼300 °C, while the chemical form of major product on the sample surface without an exposure to B 2 O 3 was suggested to be CsI from the HAXPES spectra, an intensity ratio of Cs/I was dramatically reduced at the sample surface after the reaction with B 2 O 3 . The results suggest the possibility of significant decomposition of deposited CsI induced by the chemical reaction with B 2 O 3 at specific temperatures.

In order to obtain the release rate coefficients from fuels for fast reactors (FRs), heating tests and the subsequent analyses of the fission products (FPs) and actinides that are released were carried out using samples of uranium-plutonium mixed oxide (MOX) fuel pellets irradiated at the experimental fast reactor Joyo. Three heating tests targeting temperatures of 2773, 2973 and 3173 K were conducted using an FP release behavior test apparatus equipped with a high-frequency induction furnace and solid FP sampling systems consisting of a thermal gradient tube (TGT) and filters. Irradiated fuel pellets were placed into a tungsten crucible, then loaded into the induction furnace. The temperature was raised continuously at a heating rate of 10 K/s to the targeted temperature and maintained for 500 s in a flowing argon gas atmosphere. The FPs and actinides released from the MOX fuels and deposited in the TGT and filters were quantified by gamma-ray spectrometry and inductively coupled plasma mass spectrometry analysis. Based on the analysis, the release rates of radionuclides from MOX fuels for FRs were obtained and compared with literature data for light water reactor (LWR) fuels. The release rate coefficients of FPs obtained in this study were found to be similar to or lower than the literature values for LWR fuels. It was also found that the release rate coefficient data for actinides were within the range of variation of literature values for LWR fuels.

Experiments simulating overheating conditions of fast reactor severe accidents have been previously carried out with irradiated fuels. For the present study, the chemical forms of the fission products (FPs) included in the irradiated fuels were evaluated by thermochemical equilibrium calculations. At temperatures of 2773 K and 2973 K, the most stable forms of Cs, I, Te, Sb, Pd and Ag are gaseous compounds, and their fractions are about 100% in an oxygen partial pressure range between 10−5 and 103 Pa. Cs and Sb detected in the thermal gradient tube (TGT) in the experiments can take gaseous chemical forms of elemental Cs, CsI, Cs2MoO4, CsO and elemental Sb, SbO, SbTe, respectively. The chemical forms of Cs and Mo are sensitive to the oxygen partial pressure. By comparing experimental results and the estimations, it is seen CsI thermochemically behaves in a manner that traps it in the TGT, while elemental Cs trends to move as fine particles. The moving behavior of the gaseous FPs will obey not only thermochemical principles, but also those of particle dynamics.

In order to evaluate influence of B on the release and transport of Cs and I during severe accidents, basic experiments have been performed on the interaction between deposited Cs/I compounds and vapor/aerosol B compounds. CsI and B2O3 were utilized as a Cs/I compound and a B compound, respectively. Deposited CsI on the thermal gradient tube (TGT) at temperatures ranging from 423 K to 1023 K was reacted with vapor/aerosol B2O3, and then observed how it changed Cs/I deposition profiles. As a result, vapor/aerosol B2O3 stripped a portion of deposited CsI within a temperature range from 830 K to 920 K to make gaseous CsBO2 and I2. In addition, gaseous I2 was re-deposited at a temperature range from 530 K to 740 K, while CsBO2 travelled through the sampling tubes and filters without deposition. It is evident that B enables Cs compounds such as CsBO2 to transport Cs to the colder regions.

Polycrystalline specimens of americium-containing barium plutonate have been prepared by mixing the appropriate amounts of (Pu0.91Am0.09)O2 and BaCO3 powders followed by reacting and sintering at 1...

This study examined the effects of providing vaccination education during the perinatal period on Japanese parents' knowledge, attitudes, and beliefs about childhood vaccination. A cluster-randomized controlled-trial method was used on a sample of 160 pregnant women recruited from 9 obstetrical sites in Niigata, Japan. The treatment group received a stepwise interactive education intervention, while the control group received a general vaccination leaflet. Changes in parental attitudes toward and beliefs about infant vaccination were assessed on the child's one-month and 6-month birthdays using paper questionnaires. Of the initial 188 participants, 160 (90.4%) completed the final post-survey questionnaire. Scores on injunctive social norms (a morally neutral perception of the behavior of the majority) and descriptive social norms (a moral perception of what individuals should do) significantly increased in the treatment group (p = .02 and p = .01, respectively). There was a significant difference between the 2 groups over time in terms of perceived benefit (efficacy of available preventive actions) (p = .03), but no significant differences in perceived severity (seriousness of a disease outcome), perceived susceptibility (likelihood of getting a disease), perceived benefits, perceived behavioral control, or descriptive social norms between the groups at any time point or in the patterns of change over time (p > .31). Thus, stepwise perinatal vaccination education was found to positively influence maternal attitudes and beliefs about infant vaccination. This study suggests the importance of vaccination education during the perinatal period.

Penetration behavior of radionuclides such as 137Cs into dried concrete material, dried mortar material and epoxy paint for a few dozen days was observed using a solution containing fission products extracted from irradiated fuels to obtain fundamental information on the radionuclide penetration rate and depth. Hardly any radionuclides could penetrate into the epoxy paint. The radionuclide solution penetrated into concrete and mortar materials to a depth of a few millimeters for a few dozen days. The penetration behavior observed near the surface of concrete and mortar materials was similar to the diffusion of nuclides in media such as water-saturated concrete, bentonite and cement materials.

Since the start of the severe accidents at the Fukushima Daiichi Nuclear Power Plant in March 2011, concrete surfaces within the reactor buildings (RBs) have been exposed to radioactive contaminant...

As a first step for obtaining experimental data on the effects of high-temperature chemical interaction on fission product release behavior, we focused on the dissolution of irradiated uranium plut...

Background: We estimated influenza vaccine effectiveness (VE) in 2015–2016 season against medically attended, laboratory-confirmed influenza, when quadrivalent inactivated vaccine (IIV4) was first introduced in Japan, using test-negative case-control design. Influenza A(H1N1)pdm09 cocirculated with B/Yamagata and B/Victoria during the study period in Japan. Method: We based our case definition on two laboratory tests, real-time reverse transcription polymerase chain reaction (RT PCR), and virus isolation and compared VEs based on these tests. In addition, VE was evaluated by rapid diagnostic test (RDT). Nasopharyngeal swabs were collected from outpatients who visited clinics with influenza-like illness (ILIs) in Hokkaido, Niigata, Gunma and Nagasaki prefectures. Results: Among 713 children and adults enrolled in this study, 578 were influenza positive by RT PCR including, 392 influenza A and 186 influenza B, while 135 were tested negative controls. The adjusted VE by RT PCR for all ages against any influenza was low protection of 36.0% (95% confidence interval [CI], 3.1% to 58.6%), for influenza A was 30.0% (95% CI: −10.0% to 55.5%), and influenza B was moderate 50.2% (95% CI: 13.3% to 71.4%). Adjusted VE for virus isolation for A(H1N1)pdm09 was 37.1% (95% CI: 1.7% to 59.7%), Yamagata lineage 51.3% (95% CI: 6.4% to 74.7%) and Victoria lineage 21.3% (95% CI: −50.0% to 58.9%). VE was highest and protective in 0–5 years old group against any influenza and influenza A and B/Yamagata, but the protective effect was not observed for other age groups and B/Victoria. RDT demonstrated concordant results with RT PCR and virus isolation. Sequencing of hemagglutinin gene showed that all A(H1N1)pdm09 belong to clade 6B including 31 strains (88.6%), which belong to clade 6B.1 possessing S162N mutations that may alter antigenicity and affect VE for A(H1N1)pdm09. Conclusions: IIV4 influenza vaccine during 2015–2016 was effective against A(H1N1)pdm09 and the two lineages of type B. Younger children was more protected than older children and adults by vaccination. Keywords: Influenza, Influenza vaccine, Vaccine effectiveness, Quadrivalent inactivated vaccine (IIV4), Test negative case-control design, Japan

No agglomeration of pure indium particles by the treatment with soaking in the solvent such as acetone or MEK has achieved. This is due to formation of indium-complex covering on the surface of particles. Furthermore we also have found out that a new pure indium particle works as well as conventional materials in terms of soldering properties.

The release behavior of Pu and Am was investigated under the reducing atmosphere expected in sodium cooled fast reactor severe accidents. Irradiated Pu and U mixed oxide fuels were heated at maximum temperatures of 2773 K and 3273 K. EPMA, γ-ray spectrometry and α-ray spectrometry for released and residual materials revealed that Pu and Am can be released more easily than U under the reducing atmosphere. The respective release rate coefficients for Pu and Am were obtained as 3.11 × 10 −4 min −1 and 1.60 × 10 −4 min −1 at 2773 K under the reducing atmosphere with oxygen partial pressure less than 0.02 Pa. Results of thermochemical calculations indicated that the main released chemical forms would likely be PuO for Pu and Am for Am under quite low oxygen partial pressure.

A simple formula is developed for the evaluation of the helium production amount in fast reactor minor actinide (MA) containing uranium–plutonium mixed oxide (MOX) fuel. For the subroutine use in the existing fuel behavior analysis code, the formula is designed putting emphasis on simplicity and quickness rather than accuracy. The accuracy of the formula is confirmed by comparing with the detailed calculation with SWAT code, and also with the post irradiation examination (PIE) results of the fuel pin irradiated at the experimental fast reactor JOYO. As a result, it is found that the formula evaluates the helium production amount with the difference of less than about 10% from the detailed calculation and the PIE results, when the MA isotope content is less than 5 wt.%. Based on these results, the formula is installed in the fuel behavior analysis code for the simulation of helium behavior in fast reactor fuels.

A novel X-ray source based on parametric X-ray radiation (PXR) has been put into practical use at the Laboratory for Electron Beam Research and Application (LEBRA), Nihon University, Japan. The PXR beam has been generated from a Si single crystal irradiated by a 100-MeV electron beam from a linac at the LEBRA. In this study, phase-contrast imaging experiments using a diffraction-enhanced imaging (DEI) method have been carried out by using the parametric X-rays at an energy of 17.5 keV. The successful images obtained by the DEI method have shown detailed inner structures of soft biological tissues more clearly as compared with those by conventional absorption radiography. Given the significant properties of the LEBRA PXR source, i.e., compact system, large X-ray beam irradiation field of approximately 80 mm in diameter and quasi-monochromaticity, the result suggests a possible construction of a compact linac-driven PXR-DEI device and application to medical diagnoses. Copyright © 2012 John Wiley & Sons, Ltd.

Polycrystalline specimens of strontium plutonate, SrPuO 3 , have been prepared by mixing the appropriate amounts of PuO 2 and SrCO 3 powders followed by reacting and sintering at 1600 K under the flowing gas atmosphere of dry-air. The sintered specimens had a single phase of orthorhombic perovskite structure and were crack-free. The elastic moduli of SrPuO 3 were determined from the longitudinal and shear sound velocities. The Debye temperature was also determined from the sound velocities and lattice parameter measurements. The thermal conductivity of SrPuO 3 was calculated from the measured density at room temperature, literature values of heat capacity, and thermal diffusivity measured by laser flash method in vacuum. Although the thermal conductivity of SrPuO 3 slightly decreased with increasing temperature to 800 K, the range of change was extremely narrow and the temperature dependence did not completely follow the 1/ T law. The thermal conductivity of SrPuO 3 was lower than those of other perovskite type oxides.

The clinical effectiveness of the newly released neuraminidase inhibitors (NAIs) laninamivir and peramivir has not been sufficiently evaluated in influenza-infected patients in clinical and practical settings. In this study, we analyzed the clinical data of 211 patients infected with influenza A virus subtype H3N2 (A(H3N2)) and 45 patients infected with influenza A virus subtype H1N1pdm (A(H1N1)pdm09) who received the NAIs oseltamivir, zanamivir, laninamivir, or peramivir during the 2010-2011 influenza season. The duration of fever from the first dose of the NAI to fever alleviation to

Although multi-sized particles slurries are transported in practical pipelines, most reported correlations were proposed for single-size slurries. If the average diameter of solids is used to estimate the drag coefficient of multi-sized particles slurries, the hydraulic gradients with these correlations lead to considerable scatter of data . Kazanskij , Moro , and STSJ (Slurry Transport Society of Japan) [4] summarised some empirical equations of hydraulic gradient of slurry flow with experimental data. The Wasp method [5] recommended by Liu [6] has been used by designers of pipeline systems for predicting hydraulic gradient of compound slurries of homogeneous and heterogeneous flows. However, the method is limited for application to a wide range of transport conditions. Kaushal et al. [7] also discussed the limitations and attempted to modify the method. They concluded that the Wasp method provided reasonable accurate results at limited low concentrations. The purpose of this paper is to discuss the limitations of application of other researchers' correlations and to develop innovated models, based on the single-size slurry model of Seitshiro et al. [8] The analytical models depend on particle size distribution: (1) coarse-coarse model; for a slurry consisting of two fine particles in high concentration. The fine solids are defined as particles with sizes smaller than the critical diameter [9] in this study. For both models, it is assumed that the coarse solids in the slurry do not hinder each other's movements. Experiments were performed in a 1-inch transparent pipe with sand-bakelite mixed slurries. The data of Shook et al. , Boothroyde et al. , and that of this study were used to verify the application of the models. The analytical results suggest that the innovated models can be effective for designing slurry pipelines.

The melting temperatures of FBR MOX fuels with Pu content of 28–30 wt.% irradiated to from 22.5 to 112.5 MWd kg−1 were measured using a rhenium inner capsule to hold the specimens. The rhenium inner capsule could prevent chemical reactions between fuels and tungsten materials which decrease the melting temperature. The melting temperatures were about 30 K higher than the previous data using tungsten capsules. The melting temperature decreases in a linear manner with burnup due to solid solution of fission products in fuels. However, the slopes of the lines plotting melting temperature versus burnup are almost similar to the previous data.

Behavior of helium and fission gases in irradiated mixed oxide (MOX) fuels was investigated by pin puncture and heating tests by quantitatively measuring amounts of helium and fission gases in a fuel pin irradiated in JOYO to ∼50 MW d kg−1 as a whole pin average burnup. While the fission gas releases were 47% and 48% for Kr and Xe respectively, all helium generated during irradiation was released (∼100%), and the helium released during the heating test was derived from α-decay after irradiation. The release profile during the heating test indicated that helium gas release onset temperature was below 1173 K at an isothermal condition, but during irradiation, the helium release behavior could be understood by taking its high diffusion coefficient into consideration. The different release behavior of helium and fission is mainly explained by their different mobility in the fuel.

Polycrystalline specimens of barium plutonate, BaPuO3, have been prepared by mixing the appropriate amounts of PuO2 and BaCO3 followed by reacting and sintering at 1600 K under the flowing gas atmosphere of dry-air. The sintered specimens had a single phase of orthorhombic perovskite structure and were crack-free. The Debye temperature of BaPuO3 was determined from the sound velocity and lattice parameter measurements. The elastic moduli were also determined from the longitudinal and shear sound velocity. The thermal conductivity of BaPuO3 was calculated from the measured density at room temperature, literature values of heat capacity, and thermal diffusivity measured by a laser flash method in vacuum. The thermal conductivity of BaPuO3 was roughly independent of the temperature and was almost the same magnitude as that of BaUO3. This was markedly lower than the conductivities of other perovskite type oxides and was about one-tenth that of UO2 around room temperature. The temperature dependence of the thermal conductivity of BaPuO3 was found to be quite similar to that of BaUO3.

The transport conditions of solids in slurry pipelines cause the flow behavior of solid-liquid mixture to vary strongly and affect the hydraulic gradients in the systems. Since any transport design or correlation for slurry transport should be confirmed by a wide range of data, experiments in various flow regimes have been carried out over the years by different researchers. This study was, therefore, aimed at developing a slurry transport database for accumulation, input, editing, sorting, storing of the data available in literature and displaying the results in graphical form for comparison. A basic processing procedure was adopted for the design of the program. Then a flowchart of the program was developed to process the data. The flowchart consisted of three subflowcharts: input-for the input and addition of data; editing-for modifying and standardizing all the data into the Excel CSV form; and graph displays of the data-for comparison of the researchers' data on log-log graphs. Star graphs were used to give a clear description of the transport conditions for each researcher. The database was applied for the verification of proposed correlations for predicting the hydraulic gradients of slurry flow in pipes.

Neuraminidase inhibitors are agents used against influenza viruses; however, the emergence of drug-resistant strains is a major concern. Recently, the prevalence of oseltamivir-resistant seasonal influenza A (H1N1) virus increased globally and the emergence of oseltamivir-resistant pandemic influenza A (H1N1) 2009 viruses was reported. In this study, we developed a cycling probe real-time PCR method for the detection of oseltamivir-resistant seasonal influenza A (H1N1) and pandemic influenza A (H1N1) 2009 viruses. We designed two sets of primers and probes that were labeled with 6-carboxyfluorescein or 6-carboxy-X-rhodamine to identify single nucleotide polymorphisms (SNPs) that correspond to a histidine and a tyrosine at position 275 in the neuraminidase protein, respectively. These SNPs confer susceptibility and resistance to oseltamivir, respectively. In the 2007-2008 season, the prevalence of oseltamivir-resistant H1N1 viruses was 0% (0/72), but in the 2008-2009 season, it increased to 100% (282/282). In the 2009-2010 season, all of the pandemic influenza A (H1N1) 2009 viruses were susceptible to oseltamivir (0/73, 0%). This method is sensitive and specific for the screening of oseltamivir-resistant influenza A (H1N1) viruses. This method is applicable to routine laboratory-based monitoring of drug resistance and patient management during antiviral therapy.

Tooth enamel is composed of nano-scale, needle-like biological apatite crystallites. These crystallites constitute the enamel prisms. The generally accepted Meckel's model of arrangement of crystallites in enamel prism might be slightly revised according to the variations in tooth enamel chemical composition and structures. An x-ray diffraction method was proposed to survey the three-dimensional crystallite orientation instead of electron microscopy. Preliminary results showed clear difference in the convergence and broadening of enamel crystallite orientations of human tooth enamel. This method has high potential in analyzing partial deviation in crystallite orientation as well as easy sample preparation and operation.

Parametric X-ray (PXR) is a new type of radiography with variable monochrome wavelength and high coherent characteristics. The Laboratory for Electron Beam Research and Application (LEBRA) at Quantum Science Institute, Nihon University generated LEBRA-PXR, a system that irradiates Si crystal with electron accelerated by linear accelerator (LINAC). LEBRA-PXR is uniquely developed for world-wide application experiment. X-ray images of tooth samples were taken with flat panel detector using LEBRA-PXR. As a result, images were captured as short as 1 sec. LEBRA-PXR uses LINAC with micro-macro pulse electron beam structure. Imaging time of 1 sec is equivalent to about 0.025 msec when x-ray is converted to actual radiation exposure. The effective dose point estimates of x-rays were about 1 μ Sv/5 sec. Results show that LEBRA-PXR can be used to generate low dose x-ray imaging advocating the possibility of its application in biological studies and medical treatment.