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The target vessel, which enclosing liquid mercury, for the pulsed spallation neutron source at the J-PARC is severely damaged by cavitation caused by proton beam-induce pressure waves in mercury. To mitigate the cavitation damage, we adopted a double-walled structure with a narrow channel for the mercury at the beam window of the target vessel. The narrow channel disturbs the growth of cavitation bubbles due to the pressure gradient. In addition, gas microbubbles are injected into the mercury to suppress the pressure waves. After finishing service operation, the front end of the target vessel was cut out to inspect the effect of those cavitation damage mitigation technologies on the interior surface. The damage depth of the cutout specimens for the original design type and double-walled target vessels were quantitatively investigated by the replica method. The results showed that the double-walled target facing mercury with gas microbubbles operate 1812 MWh for an average power of 434 kW is equivalent to the damage of original design target operated 1048 MWh for average power of 181 kW. The erosion depth due to cavitation in the narrow channel is clearly smaller than on the wall facing bubbly mercury.

Neutron flux per pulse reached world record at neutron source in Japan Proton Accelerator Research Complex (J-PARC). In the J-PARC, mercury target system is used as a spallation neutron source. A t...

A mercury target vessel made of 316L SS is damaged due to the cavitation caused by the pressure waves in mercury. Cavitation damage reduces the structural integrity of the target front, called "beam window", being major factor to determine the lifetime of target vessel. Aiming at mitigating the cavitation damage by faster mercury flow in narrow channel, we employed a target vessel with a double-walled structure at the beam window along with a gas microbubbles injection. After operating the double-walled target vessel with a beam power of 300 to 500 kW, we cut out the beam window using an annular cutter to examine the damage inside it, and found that damages with maximum pit depth of approximately 25 $\mu$m distributed in a belt on the specimen facing narrow channel. Furthermore, numerical simulation result showed that the distribution of negative pressure period from beam injection to 1 ms was correlated with the damage distribution in the narrow channel. It was suggested that the cavitation induced by relatively short negative pressure period contributed to the damage formation., J-PARCの核破砕中性子源の水銀ターゲット容器(SUS316L製)は、ビーム窓と呼ばれる厚さ3mmの先端部分が、陽子線励起圧力波よるキャビテーションにより壊食損傷する。この損傷は容器の構造健全性を低下させ、容器の寿命の決定因子となっている。我々は、2014年からキャビテーション損傷及びそれを誘発する圧力波を低減するために、気泡注入に加えて狭隘流路を設置することで、ビーム窓の水銀流速を速める2重壁構造を採用し、300$\sim$500kWの強度で運転を行った。使用済みの容器を切断し、内壁を観察した結果、狭隘流路の内側で最大深さ約25$\mu$mの帯状の損傷が観測された。この原因を調べるために、負圧の持続時間に着目した圧力波伝ぱ解析を実施した結果、ビーム入射直後から1msまでに生じる負圧の持続する時間をマッピングした結果と、形成された損傷の分布がよく対応しており、比較的短時間の負圧によって生じるキャビテーションが損傷形成に寄与していることを示唆した。

An examination of the structural integrity and defects of a fabricated mercury target vessel for Japan Proton Accelerator Research Complex (J-PARC) spallation neutron source is presented. Ultrasonic testing (UT) and radiographic testing (RT) were employed as nondestructive inspection methods. The mercury target vessel is composed of SUS316L stainless steel and was designed with multi-walled structures consisting of double-guard vessels with thin walls of 3-mm thickness and assembled by tungsten inert gas welding. The mercury target vessel has complex characteristic, and the weld defect for the thin walls is often very difficult to detect using conventional UT techniques. To overcome this barrier, we employed two new UT techniques, namely 1) immersion ultrasonic with a 50-MHz ultrasonic probe and 2) phased arrays ultrasonic with the full matrix capture (FMC) and the total focusing method (TFM). The examination revealed the formation of small defects and cracks wherein the wall thickness was less than 6 mm. Therefore, new UT techniques are useful for evaluating the structural integrity and defects of the new fabricated mercury vessels. The design and the fabrication process of the mercury target vessel was also evaluated and improved in this study. The use of wire electric discharge machining (EDM) in the fabrication process is desirable to reduce the amount of welding and subsequent welding deformation. The roughness and chemical compositions of the processed surface layer by wire EDM were also examined. The oxide layer was perfectly removed by two-step chemical polishing, and the chemical composition of the layer was analyzed using energy dispersive X-ray spectrometry. In addition, the surface roughness was reduced after polishing to enhance fatigue life and minimize internal defects caused by welding.

The spallation neutron source at the Japan Proton Accelerator Research Complex (J-PARC) mercury target vessel is used for various materials science studies, work is underway to achieve stable operation at 1 MW. This is very important for enhancing the structural integrity and durability of the target vessel, which is being developed for 1 MW operation. In the present study, to reduce thermal stress and relax stress concentrations more effectively in the existing target vessel in J-PARC, an optimization approach called the Taguchi method (TM) is applied to thermo-mechanical analysis. The ribs and their relative parameters, as well as the thickness of the mercury vessel and shrouds, were selected as important design parameters for this investigation. According to the analytical results of 18 model types designed using the TM, the optimal design was determined. It is characterized by discrete ribs and a thicker vessel wall than the current design. The maximum thermal stresses in the mercury vessel and the outer shroud were reduced by 14% and 15%, respectively. Furthermore, it was indicated that variations in rib width, left/right rib intervals, and shroud thickness could influence the maximum thermal stress performance. It is therefore concluded that the TM was useful for optimizing the structure of the target vessel and to reduce the thermal stress in a small number of calculation cases.

A silver-indium-cadmium (Ag-In-Cd, or AIC) alloy with a 1 eV high neutron cut-off energy was originaly developed as a decoupler to provide a narrow neutron pulse width with a short tail for the J-PARC 1-MW short-pulsed spallation neutron source. As a result of later studies, gold (Au) was chosen as a substitute for Ag for the production of spare decoupled moderators and reflector in order to reduce residual radioactivity thus easing handling and disposal of the spent moderator and reflector. The decoupler material Au-In-Cd (AuIC) was therefore investigated and developed. To implement it into an actual moderator-reflector assembly many critical engineering issues needed to be resolved with regard to large-sized bonding between AuIC and aluminum alloy A5083 by the hot isostatic pressing process (HIP). The HIP process for AuIC and aluminum was investigated in terms of surface condition, size, and heat capacity. Implementation of an AuIC decoupler into a spare reflector assembly was successfuly achieved and will result in a remarkable reduction of radioactivity compared to AIC without sacrificing neutronic performance.

This study explores high-energy neutron components of the extracted neutron beam at J-PARC pulsed neutron source using the foil activation method with threshold reactions. Foils of aluminum, gold, bismuth, niobium, and thulium were used to cover the neutron energy range from 0.3 MeV to 79.4 MeV. The experiment was performed using neutron beams of BL10 (NOBORU). The foils were irradiated by a neutron beam at 13.4 m from the moderator. To characterize high-energy neutron fields for irradiation applications, reaction rates in three different configurations with and without B 4 C slit and Pb filter were examined. To compare the experiments with calculations given for the user, reaction rates for corresponding reactions were calculated by the PHITS code with the JENDL-3.2 cross sections and the JENDL dosimetry file. Although there was a systematic tendency in C/E (Calculation/Experiment) ratios for different threshold energies, which C/E ratio decreased as threshold energy increased up to 100 MeV, all C/E ratios were in the range of 1.0 ± 0.2. This indicated that high-energy neutron calculations were adequate for the analysis of experimental data for NOBORU users.

Japan Proton Accelerator Research Complex experienced failures of two mercury targets, which were Target #5 and #7, in 2015 when the facility was operating with a proton beam power of 500 kW. The failures involved coolant water leak from the water shroud. In this paper, we investigate the root cause of the Target #5 failure. The results of the visual inspections, mockup tests, and analytical evaluations suggested that the water leak was caused by the possible combination of two incidents. One was the diffusion bonding failure due to the large thermal stress induced by welding of the bolt head during the fabrication process, and the other was the thermal fatigue failure of the seal weld due to the repetitive beam shutdown during beam operation. Though the investigation into the root cause of the Target #7 failure is still going on, these target failures point to the importance of eliminating initial defects and the need to secure the rigidity and stability of welded structures. The next mercury tar...

Mercury target vessel in the JSNS, which is made of 316L SS, is damaged owing to the pressure wave-induced cavitation resulting from the proton beam bombardment. The cavitation damage decreases the structural integrity of the target vessel and is currently a dominant factor to decide the service life in compared with the radiation damage. Injecting microbubbles into mercury is one of the prospective techniques to mitigate the pressure waves and cavitation damage. In the JSNS, a microbubble generator with a gas circulation system was installed and has been operated since October 2012. The effects of microbubble injection into mercury on pressure wave mitigation were studied using a laser Doppler vibrometer. The result showed that the vibrational velocity of the target vessel is clearly reduced according to the increase of void fraction. An average peak vibrational velocity under 340 kW operation with the void fraction of 0.1\% was reduced to 1/4 of that without injecting microbubbles., J-PARCの核破砕中性子源(JSNS)水銀ターゲット容器は、陽子線入射励起圧力波により励起されるキャビテーションによる損傷を受ける。キャビテーションによる損傷は、容器の構造健全性を低下させるため現在のところ容器の交換寿命を決める支配因子となっている。圧力波及びキャビテーションによる損傷を低減するためには、水銀中にガスマイクロバブルを注入することが効果的な手法である。JSNSでは、ガスマイクロバブルを注入するためのシステムを2012年10月に設置し、レーザードップラー振動計を用いて容器の振動をモニタリングすることによって水銀中へのバブル注入の効果をした。その結果、振動速度は気泡注入量の増加に伴って減少することを確認した。また長期間の運転では、気泡注入によって平均でバブル注入無しの1/4程度の振動速度を維持した。

AIM: To investigate the occurrence and severity of pruritus in chronic hepatitis C patients treated with or without interferon (IFN) therapy. METHODS: A total of 89 patients with chronic hepatitis C and 55 control (non-hepatitis) patients were asked to rate their experience of diurnal and nocturnal pruritus in the preceding week using a visual analogue scale (VAS) and a five-point scale, respectively. Blood samples were taken and serum thymus and activation-regulated chemokine (TARC) levels were measured by enzyme-linked immunosorbent assay. RESULTS: A significantly greater proportion of chronic hepatitis C patients experienced nocturnal pruritus compared with control (58.4% vs 5.5%, P < 0.0001). Chronic hepatitis C patients also had more severe pruritus compared with control patients, indicated by the higher mean VAS scores in both the IFN-treated and non-IFN-treated groups. In particular, patients who received combined peginterferon alfa-2b and ribavirin had significantly higher mean VAS scores than those receiving peginterferon alfa-2a or no IFN treatment. Serum TARC levels did not correlate with pruritus scores, and no significant differences in TARC levels were observed between the IFN-treated and non-IFN-treated groups. CONCLUSION: Patients with chronic hepatitis C experience pruritus more than those without. Serum TARC levels do not correlate with pruritus severity in chronic hepatitis C patients.

At the Japan Proton Accelerator Research Complex (J-PARC), a pulsed spallation neutron source provides neutrons with high intensity and narrow pulse width pulse to promote researches on a variety of science in the Materials and Life Science Experimental Facility (MLF). It was designed to be driven by a proton beam with an energy of 3 GeV, a power of 1 MW at a repetition rate of 25 Hz, that is world’s highest power level. It is still on the way towards the goal to accomplish the operation with a 1 MW proton beam. In this review, distinctive features of the target-moderator-reflector system of the pulsed spallation neutron source are presented.

In Japan Spallation Neutron Source (JSNS) in Japan Proton Accelerator Research Complex (J-PARC), a fabrication of the second moderator from 2013 is planned. Invar ducts having a low-thermal expansion coefficient are used as the moderator piping. For the fabrication, examinations of the Invar duct were carried out; tensile tests of dissimilar joints by friction welding, a bending test by a bender and a welding test by TIG welding. As the results, it was found that bonding strengths of the Invar dissimilar joints at 77 K were larger than those at room temperature. It was also found that the dissimilar joints of Invar-A6061-T6 and Invar-SS316L have larger bonding strengths than base materials. The Invar ducts of 22 mm in diameter could be bent into an elbow with 44 mm in radius with slow speed after pre-cooling at 77 K. There wasn’t any failure in butt welding testes by TIG-welding. These results indicate that the Invar duct is available as the moderator piping of the second moderators.

The Materials and Life Science Experimental Facility (MLF) in J-PARC is a facility which generates neutron and muon beams by injecting highly intense pulsed proton beams into targets and supplies them to user experimental instruments. In the MLF, an interlock system (MLF-IL) is running to keep safety operations of the facility in various situations such as beam irradiations and target maintenances. Since the first proton beam injection in 2008, the MLF-IL has been operated stably without any serious troubles in spite of the device upgrades in the target systems and the increase of user instruments. This paper describes the design concept, the operation and the modification of the MLF-IL.

Background/Aims:To compare the use of protein induced by vitamin K absence or antagonist II( PIVKA-II) measured conventionally with the ratio between PIVKA-II measured using P-11 and P-16 antibodies(NX-PVKA) and PIVKA-II measured conventionally (NX-PVKA-R) in terms of false-positive resultsfor hepatocellular carcinoma( HCC). Methodology:Subjects comprised 318 patients with chronic liver disease,including 8 patients receiving warfarin treatment, which can result in false-positive results for HCC.HCC was present in 65 patients (HCC group) and absent in 253 (non-HCC group). PIVKA-II was measuredconventionally. NX-PVKA-R was calculated as PIVKA-II/NX-PVKA. Results:Both PIVKA-II andNX-PVKA-R were significantly higher in the HCC group than in the non-HCC group (p

Microfluidics is a rapidly growing field in which small volumes of liquid are moved through channels in a large variety of applications. Fabricating such channels can be expensive. Here, we describe an inexpensive method for making 3D channels in fluidic chips by using a sacrificial template made of coated metal wire or metal tubes. A 3D template is embedded in polymer or glass and then dissolved, leaving channels in the chip, without the need for expensive instruments. By changing the mold, chips of various shapes can be made.

69 歳,女性.2004 年に他院耳鼻科にてシェーグレン症候群と診断され治療中であった.2010 年5月に肝機能障害を指摘されたために当科を受診した.初診時に両側上眼瞼の腫脹と両側耳下腺の腫大(約1 cm)を認めた.血液生化学検査では胆道系酵素の上昇を認め,またIgG は2308 mg/dl,IgG4 は498 mg/dl と高値を呈した.造影CT では膵はびまん性に腫大していた.内視鏡的逆行性膵胆管造影で膵管に特徴的な狭細像を認めたため自己免疫性膵炎と診断した.本症例の眼瞼腫脹と顎下腺腫脹は現在の診断基準ではMikulicz 病と診断が可能である.Mikulicz 病と自己免疫性膵炎の合併は少なくないものの,本邦における文献報告例は本例で11 例目である., A 69-year-old woman presented with a chief complaintof liver dysfunction in May 2010. Both palpebrae superiorand the parotid gland had been swollen for six years. Bloodtests showed increased levels of biliary system enzymesand serum IgG and IgG4. Enhanced computed tomographyrevealed a diffusely enlarged pancreas. A narrowed pancreaticduct revealed by endoscopic retrograde cholangio-pancreatographywas diagnosed as autoimmune pancreatitis.The swollen eyelid and enlarged submandibular gland indicateda diagnosis of Mikulicz's disease. Case reports of Mikulicz'sdisease complicated with autoimmune pancreatitisare very rare.

The J-PARC 1 MW pulsed spallation neutron source JSNS was successfully launched on 30th of May 2008. To demonstrate the unique features of the moderator design and the neutronic performance of JSNS the neutron spectral intensity, absolute neutron flux, and time structure of the neutron pulse shapes etc. have been measured using several neutron instruments since then. The measured energy spectra clearly revealed the feature of the para-hydrogen, as expected when designing the moderator. The measured neutron flux below 0.4 eV agreed with the corresponding design value within ±20%, thus suggesting that the JSNS design calculations to have been reliable. World-class high-resolution diffraction data could be recorded due to the suitability of design of the moderators and the instruments. Another world-class high-intensity neutron flux was also capable of being demonstrated due to the unique design of the large cylindrical coupled moderator.

An off-gas processing system was installed in the J-PARC spallation neutron source to reduce radioactivity of xenon-127 and tritium contained in a helium cover gas in a surge tank of a mercury circulation system to obey the regulation by law. In addition to this role it has been utilized to a purging process before the target vessel replacement and an air-flow control procedure to minimize uncontrollable radioactivity release during the replacement. An standard and urgent model plans of the off-gas processing system operation were established indicating that 31 days were required at least to replace the target vessel.

In recent years, there have been various problems in medical treatments, of which human error by the surgeon in an operation is one of the most serious. In order to minimize human error in an operation, we need a medical training system by which inexperienced surgeons can try operating again and again to improve their skill. In this research, we construct a system of modeling a virtual dense elastic object, and deforming that object using a haptic device called PHANToM. In the system which we construct, we use two PCs to distribute the process of calculation, and SCRAMNet+ is used to connect each PC. PHANToM is used to operate on the object and to express the force which is generated from the deformation of the object. We represent the dense object by using voxels and tetrahedrons, and the elastic object by using a spring-mass model. A virtual dense elastic object is obtained by computed tomography (CT) or magnetic resonance imaging (MRI) to express the patient’s organs.

The most updated version of the JENDL high-energy file, JENDL/HE-2007, was validated with a focus on heavy elements of W, Pb, and Hg through analyses of spallation experiments using thick targets at incident proton energies from 0.5 to 2.83 GeV. For this purpose, the processing of the PHITS code system was adjusted to simulate nucleon transport phenomena using only a cross-section library including pionproduction data up to 3 GeV with the aid of an intranuclear cascade evaporation model to treat reactions induced by accompanied pions. It was found that the data up to 3 GeV in JENDL/HE-2007 predict the neutron spectra produced in thick targets with energies lower than 15MeV with good accuracy while they underestimate those from 20 to 100MeV by a factor of 0.4 to 0.5. It is also confirmed from analyses of the reaction rates in thick targets that the cross-section data of the dosimetry reactions of 93Nb(n,4n)90Nb and 59Co(n,4n)56Co for high-energy neutron field are reasonable. The present benchmark is the fi...

A lot of even and uneven settlement is expected to occur due to the heavy weight of the buildings and shields located at the Materials and Life Science Experimental Facility (MLF) and in the proton beam line (3NBT) that runs from the 3 GeV Rapid-Cycling Synchrotron (RCS) to the neutron target at the Japan Proton Accelerator Research Complex (J-PARC). Because of this, and in order to achieve the necessary alignment of less than 1 mm in precision, the settlement that has occurred with the MLF building and the 3NBT tunnel has been periodically surveyed (level measurement) since June 2004 until now when the MLF building has been completed. The survey results were used in determining the levels at which the beam line components were installed. The survey results indicated that the values of the settlement that had taken place were almost proportional to the located weight and could be used in estimating the settlement that would take place in the future. These results were reflected in the alignment of the proton and beam line components.

Aim: In patients with hepatitis C virus (HCV)-associated chronic liver diseases, especially in those with liver cirrhosis, accurate evaluation of their protein nutrition status is very important to improve their quality of life. Whereas the serum albumin level is commonly used to evaluate patients' protein nutrition status, in the present study, the serum amino acid levels were measured, as they also provide valuable information. Methods: Serum albumin levels and branched-chain amino acids (BCAA) to tyrosine ratio (BTR) were determined in 447 patients with HCV-associated chronic liver diseases (313 with chronic hepatitis and 134 with liver cirrhosis). Results: Chronic hepatitis progressed to liver cirrhosis, serum albumin and serum BTR levels decreased significantlyas chronic hepatitis progressed to liver cirrhosis. Hypoalbuminemia was significantly more common in patients with liver cirrhosis than in those with chronic hepatitis; however, the incidence of an amino acid imbalance was significantly higher than that of hypoalbuminemia in patients with liver cirrhosis. The presence of an amino acid imbalance was associated with a reduction in the serum albumin level 1 year later. Conclusions: It is important to evaluate serum albumin levels and the BTR in patients with HCV-associated chronic liver diseases.

The monitoring and operation (MO) system for the general control system (GCS) of the Materials and Life Science Experimental Facility (MLF) was upgraded. The MLF-GCS comprises programmable logic controllers (PLCs), operator interfaces (OPIs) for integral control and interlock systems, and shared servers. The system controls various components of the pulsed spallation neutron source such as a mercury target and hydrogen moderators. The MO system is used for monitoring, alarm notification and remote control from the MLF control room. The upgraded MO system operates with the EPICS framework, the OPI of Control System Studio (CSS), and the server software of PostgreSQL. The upgraded system has been operating since January 2014 without serious trouble. This paper describes an overview of the work experience upgraded MO system.

The facility has resumed since 17th February 2014 after reformation of operation safety system required from the new regulation because of the accident in the Hadron Facility in May 2013. During eight-month shutdown period various hardware components have been improved; such as installation of additional RFQs in Linac to increase its energy to achieve higher power, repairing and replacement on the mercury (Hg) cooling loops of the neutron target, improvement on the cryogenic system for stable operation, etc. In order to mitigate the pitting damage on the Hg-target container we have been injecting helium micro bubbles in the target. The laser Doppler vibrometory showed us that vibration on the proton bombardment has been drastically reduced by the injection. Twenty one instruments have been already installed. Sixteen instruments are operated for user program and four instruments are under either commissioning or construction. Now the experimental hall is almost full with instruments, leaving only 2 ports available for the future use. Operational time for user program in JFY2014 was about 170 days, and we received more than 700 general experimental proposals from users. World-class scientific outputs have been being created in various scientific fields, ranging from Li-battery science to bio-molecular science. Since J-PARC is internationally open for users, we have got experimental proposals from abroad, which are more than 15% of the whole proposals. More than 20% of proposals have come from industries and a half of them are proprietary use. This fact has revealed a new horizon has come in the neutron scattering science in the 21 century.

Myostatin (Mstn) is a member of the transforming growth factor-β (TGF-β) family that inhibits muscle differentiation. In this study, we aimed to identify the relationships between Mstn, thyroid hormone receptor alpha (TRα), and myosin heavy chain (MyHC) isoform expression during early postnatal development.We investigated the expression of Mstn, TRα, and MyHCs (embryonic, slow, IIa, IIb, and IIx) using quantitative real-time RT-PCR and ELISA (Mstn) in postnatal mouse muscles between day 0 and day 10. We also examined the correlations between Mstn, TR and MyHCs during the early development of mouse masseter muscle (MM) and rectus femoris muscle (RFM).Distinct Mstn mRNA expression patterns were observed in the two muscles despite nearly non-significant changes in the Mstn protein abundance in MM. The expression pattern of the TRα mRNA in the MM differed from that observed in the RFM. The expression of MyHC IIa, IIb and IIx mRNAs increased in the MM and decreased in the RFM from day 0 to day 10, whereas embryonic fiber MyHC mRNA expression was similar in both muscle types. Principal component analysis showed the existence of a correlation between: (1) TRα and MyHC, (2) Mstn and MyHC, and (3) TRα and Mstn in MM. The correlations were different in RFM and MM. Cluster analyses identified the distinct clusters: cluster 1, days 0-4 for the MM and day 0 for the RFM; cluster 2, day 6 for the MM and day 2 for the RFM; and cluster 3, days 8-10 for the MM and days 4-10 for the RFM.These data suggest that TRα influences MyHC expression in both muscle types. In addition, Mstn has a limited effect in the MM related to the expression of individual MyHCs, as opposed to its role in the RFM, at early postnatal developmental stages. TRα could be involved in regulating both the temporal expression of MyHCs and Mstn at the early postnatal stages in the MM and RFM.

In the present study, a sooting flame was formed in a reduced-pressure combustion chamber using the vitiated coflow burner with a premixed flame of methane and oxygen for the surrounding flame and premixed flame of toluene, methane and oxygen for the center flame. Collected soot samples were analyzed using the high performance liquid chromatography (HPLC) and a gas chromatography to determine the fullerene content of soot and the species of PAHs under various conditions. Effects of pressure and equivalence ratio to the formation of the PAHs and fullerenes and the branching mechanism between fullerene and soot were discussed. When the fullerene content in soot samples was relatively high, the fractions of anthracene and benzo [a] anthracene were relatively high. When the fullerene content in soot samples was relatively low, the fractions of phenanthrene, flouranthene and pyrene were relatively high. Under the same pressure condition, there was an optimal flow rate of toluene in the center flame for formation of C60 and C70 of which range became wider with the decrease of pressure condition.

A ceramic micro fabrication process has been developed for the 1-3 piezo-electric composites which is suitable for high frequency, wideband ultrasonic transducer. This process employs synchrotron radiation (SR) lithography and a micro molding process. This process realized an array of lead zirconate titanate (PZT) rods whose cross section is 25 microns. The material is expected to improve the resolution of the ultrasonic diagnosis, because composites can transmit a short ultrasonic pulse and have high sensitivity. In addition, when circular shape PZT rods is arranged at the apex of the regular triangle, the internal resonant mode became clear to be suppressed.

In December 2001, we measured the in beam high-energy neutron intensities on several of the beamlines at the spallation neutron source at the Lujan Center, Los Alamos, USA. This effort was then followed by a comparison of these measurements with Monte Carlo transport simulations. In this paper we present the results of these simulations and their comparison with the measurements.

A neutronic benchmark experiment on a simulated spallation neutron target assembly was conducted by using the Alternating Gradient Synchrotron at Brookhaven National Laboratory and was analyzed to investigate the prediction capability of Monte Carlo simulation codes used in neutronic designs of spallation neutron sources. The target assembly consisting of a mercury target, a light water moderator, and a lead reflector was bombarded by 1.94-, 12-, and 24-GeV protons, and the fast neutron flux distributions around the target and the spectra of thermal neutrons leaking from the moderator were measured in the experiment. In this study, the Monte Carlo particle transport simulation codes NMTC/ JAM, MCNPX, and MCNP-4A with associated cross-section data in JENDL and LA-150 were verified based on benchmark analysis of the experiment. As a result, all the calculations predicted the measured quantities adequately; calculated integral fluxes of fast and thermal neutrons agreed approximately within ±40% with the experiments although the overall energy range encompassed more than 12 orders of magnitude. Accordingly, it was concluded that these simulation codes and cross-section data were adequate for neutronics designs of spallation neutron sources.

We have measured neutronic performance of the moderators at the Manuel Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory in order to provide the neutron beam characteristics for the neutron scattering experiments at the Lujan Center as well as to study the validity of neutronic calculation codes. The absolute neutron intensities, the energy spectra, and the neutron pulse shapes (neutron emission time distributions) were measured for the H2O coupled moderator, the high-intensity H2O decoupled moderator, the high-resolution H2O decoupled moderator, and the partially coupled liquid-hydrogen moderator. The overall characteristics of the moderators were found to agree with the designed performance.

BACKGROUND There has been recent interest in the importance of visceral fat (VF) for the development of atherosclerosis. The purpose of this study was to examine associations between VF and multiple risk factors as well as the prevalence of carotid atherosclerosis in chronic haemodialysis patients. METHODS We classified 77 non-diabetic haemodialysis patients into 'low VF', 'middle VF' and 'high VF' groups after determining VF area using computed tomography. Systemic atherosclerosis was assessed from intima-media thickness (IMT), plaque score (PS) and stiffness parameter beta (stiffness-beta) measured by high-resolution B-mode ultrasonography. RESULTS Compared with the low VF group, the high VF group exhibited (i) significantly higher fasting plasma insulin (11.0 +/- 6.8 vs 7.1 +/- 2.9 micro U/ml, P = 0.0061); (ii) significantly higher plasma triglycerides (141.8 +/- 94.0 vs 86.5 +/- 32.5 mg/dl, P = 0.0032); and (iii) significantly lower plasma high-density lipoprotein cholesterol (42.1 +/- 14.5 vs 53.0 +/- 15.7mg/dl, P = 0.0134). Moreover, the high VF group had a higher prevalence and extent of carotid atherosclerosis: IMT was 0.69 +/- 0.13 vs 0.61 +/- 0.12 mm (P = 0.0239), PS was 4.8 +/- 3.2 vs 2.4 +/- 3.6 (P = 0.0236) and stiffness-beta was 11.4 +/- 3.1 vs 8.5 +/- 3.0 (P = 0.0082) in the high and low VF groups, respectively. CONCLUSION We show that VF is associated with the prevalence of carotid atherosclerosis as well as with hyperinsulinaemia and lipid abnormalities in chronic haemodialysis patients.