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Background: Recently, endoscopic biliary sphincterotomy (EBS) followed by large-diameter balloon dilation has been used for the removal of large bile duct stones. A limitation is the need for 2 accessories: a sphincterotome and a dilating balloon. Objective: To evaluate a new device, a combination of a large-diameter dilating balloon and sphincterotome (LDDBS). Design: Retrospective study. Setting: University hospital. Patients: Eighteen patients with large bile duct stones. Interventions: After performing EBS by using the LDDBS, the catheter was then advanced into the bile duct and balloon dilation was performed by gradual inflation with diluted contrast medium under endoscopic and fluoroscopic guidance until it reached a diameter adequate to allow stone removal. Main Outcome Measurements: Feasibility and efficacy of stone removal by using an LDDBS. Results: Technical success of large-diameter balloon dilation after EBS was achieved in all cases. Bile duct clearance was accomplished in 94% (17/18) of cases in the first session. Bile duct clearance was eventually completed in all patients. Mechanical lithotripsy was required in 4 patients (22%). There were no major intraprocedural or postprocedural complications. Limitations: Single-institution study, small sample size. Conclusions: The prototype LDDBS is safe and effective to facilitate the removal of large bile duct stones by using one accessory. [ABSTRACT FROM AUTHOR]

Abstract: Coefficients of friction were measured at elevated temperatures using a hot flat strip drawing test machine newly developed by the authors for the purpose of confirming the coefficients of friction used for the FEM simulation of hot stamping. To examine the functions of the tribo-simulator, the coefficients of friction are measured using hot rolling oil with an emulsion, which is supplied continuously, while varying the drawing speed, drawing pressure and temperature. From the experimental results, it was shown that the coefficient of friction in hot stamping can be measured using this tribo-simulator. The measured coefficients of friction can be used as values in the FEM simulation of hot stamping. Moreover, the tribological behavior at the interface between the die and strip in hot stamping can be evaluated from the coefficient of friction, because it is one of the quantitative values used to represent the tribological behavior between the die and blank. [Copyright &y& Elsevier]

BACKGROUND: Endoscopic papillectomy (EP) has been recognized as a safe and reliable treatment for tumor of the duodenal papilla. For complete resection, precise assessment of not only the intraductal extent but also the lateral margins of the tumor is mandatory before resection. OBJECTIVE: Our purpose was to prospectively assess the enhancement of the lateral margins of tumor of the duodenal papilla for the treatment of EP by comparing narrow-band imaging (NBI) and indigo carmine (IC) chromoendoscopy. DESIGN: Prospective study. SETTING: This procedure was performed in Tokyo Medical University Hospital. PATIENTS: Fourteen consecutive cases of tumors of the major duodenal papilla. INTERVENTION: All patients underwent EP after evaluation by NBI and IC. MAIN OUTCOME MEASUREMENT: Histologic evaluation of diagnosis of NBI and IC by comparison with en bloc tissue. RESULTS: In all lesions, either IC or NBI were superior to conventional white-light imaging except in 1 IC case. The ability of NBI observation to emphasize the tumor margin was statistically significantly better than IC observation (P< .05). The en bloc EP was endoscopically successful in all cases, without fatal adverse events. En bloc tissue revealed 13 adenomas and 1 adenoma with focal adenocarcinoma. There was no residual adenoma in lateral margin specimens, either endoscopically or histologically. LIMITATIONS: The lesions resected were all relatively small. This was not a blinded randomized study. CONCLUSION: This study demonstrated the feasibility and a certain degree of efficacy of NBI for enhancement of the tumor margin of duodenal papilla. Further blinded randomized studies involving large duodenal papillary tumors are required. [ABSTRACT FROM AUTHOR]

BACKGROUND: In patients with acute cholecystitis and at high risk for surgery, decompression of the gallbladder by percutaneous transhepatic gallbladder drainage (PTGBD) or aspiration (PTGBA) is needed as salvage therapy. However, we sometimes encounter patients in whom puncture cannot be performed for several reasons. Recently, endoscopic transpapillary gallbladder drainage (ETGD) has been reported to be safe and effective for acute cholecystitis. OBJECTIVE: Our purpose was to evaluate the clinical efficacy and safety of ETGD for acute cholecystitis in which a percutaneous transhepatic approach is contraindicated or anatomically impossible. DESIGN: Retrospective case study. SETTING: This procedure was performed in Tokyo Medical University Hospital. PATIENTS: Forty-three patients with acute cholecystitis, including 32 patients taking anticoagulation or antiplatelet drugs, 4 cases of Chilaiditi syndrome, 2 each of acute leukemia, marked ascites, and anatomic abnormality, and 1 case of hemophilia A. INTERVENTION: All patients underwent ETGD. A 5F nasobiliary-drainage catheter was placed into the gallbladder. In case of failed ETGD, PTGBD or PTGBA was performed subsequently. MAIN OUTCOME MEASUREMENT: Efficacy and safety of this technique. RESULTS: ETGD was achieved in 36 patients (84%) without any serious procedure-related complications. A clinically favorable response for ETGD was seen in 35 patients (97%). In 7 patients in whom ETGD was unsuccessful and 1 patient in which it was ineffective, a percutaneous transhepatic approach was performed with severe hemorrhage biloma in the former and uncontrolled hemorrhage cholecystitis, leading to death in the latter. LIMITATIONS: Difficulty of maneuvering the guidewire and drainage tube into the gallbladder. CONCLUSIONS: Although comparative studies are needed to define the appropriate role of ETGD and percutaneous transhepatic approach, ETGD can be useful in patients with acute cholecystitis in which a percutaneous transhepatic approach is contraindicated or anatomically impossible. [ABSTRACT FROM AUTHOR]

BACKGROUND: Endoscopic nasobiliary drainage (NBD) for the treatment of acute cholangitis is an accepted method. A recently developed ultrathin transnasal videoendoscope is minimally invasive, even for patients who are critically ill. OBJECTIVE: To evaluate the clinical efficacy and safety of 1-step NBD by transnasal videoendoscopy (TNE). DESIGN: Prospective case study. SETTING: This study was performed at Tokyo Medical University Hospital. PATIENTS: Twenty patients with acute cholangitis who had previously undergone an endoscopic sphincterotomy (ES); including 10 with bile-duct stones, 8 with pancreatic cancers, 1 with chronic pancreatitis, and 1 with benign biliary stricture, were enrolled in this study. An indwelling self-expandable metallic stent (SEMS) was placed in all patients with pancreatic cancers. INTERVENTION: All patients underwent NBD via front-viewing TNE. A 5F NBD catheter was placed into the bile duct. MAIN OUTCOME MEASUREMENT: The efficacy and safety of this technique. RESULTS: The transnasal insertion of TNE was feasible in all patients, and none had epistaxis. Abdominal pain, fever, and jaundice were improved at 24 hours after the procedure in the majority of patients. The mean procedural time was 18.1 minutes. One patient pulled out the NBD catheter. None of the patients died. TNE-NBD was achieved in 19 patients (95%). LIMITATIONS: Maneuverability of the TNE, limited to patients with a previous ES or the placement of an SEMS. CONCLUSIONS: NBD that uses TNE may be a useful and novel technique for the treatment of acute cholangitis in patients with previous ES. [ABSTRACT FROM AUTHOR]

BACKGROUND: Endoscopic biliary drainage has been established as providing effective treatment for acute obstructive jaundice and cholangitis. A recently developed ultrathin transnasal videoendoscope is less invasive, even for patients who were critically ill, and can be performed without conscious sedation. OBJECTIVE: To evaluate the clinical efficacy and safety of biliary drainage (BD) by using transnasal videoendoscopy (TNE) without conscious sedation. DESIGN: Case series. SETTING: This procedure was performed at Tokyo Medical University Hospital. PATIENTS: Three patients with bile-duct stones and acute cholangitis and with a previous biliary endoscopic sphincterotomy (ES) were included in this study. INTERVENTION: All patients underwent BD by using a front-viewing TNE. Two 5F stents were placed into the bile duct across the major papilla. MAIN OUTCOME MEASUREMENT: The efficacy and safety of the TNE technique. RESULTS: Transnasal insertion of a TNE endoscope was feasible in all patients, without epistaxis. TNE BD was achieved in all patients. Abdominal pain, fever, and jaundice improved 24 hours after the procedure in all patients. Despite the absence of intravenous conscious sedation, all patients would agree to undergo the procedure again, if necessary. LIMITATIONS: Maneuverability of the TNE endoscope; limited to patients with a previous ES. CONCLUSIONS: In this small series, unsedated TNE can be used to successfully drain the biliary system in patients with a previous ES. Additional studies to validate this hypothesis are needed. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is very important to determine the extent of intraductal mucinous neoplasms (IPMNs), because this can greatly affect the determination of the indications of surgery. Peroral pancreatovideoscopy (POPS) has been recognized as a new diagnostic tool for clear imaging of IPMN. Recently, narrow-band imaging (NBI) has made it possible to emphasize certain image features, such as mucosal structures and capillary vessels. OBJECTIVE: To evaluate the clinical usefulness of POPS by using NBI for the diagnosis of IPMN. DESIGN: Case reports. SETTING: This procedure was performed at Tokyo Medical University Hospital. PATIENTS: Three patients with IPMN. INTERVENTION: All patients underwent POPS with NBI. MAIN OUTCOME MEASUREMENT: Efficacy and safety of this technique. RESULTS: POPS with NBI was performed in 3 patients, without procedure-related complications. Identification of the surface structure and the capillary vessels by NBI observation was better than by conventional observation. Furthermore, NBI identified skip tumor lesions in the tail of pancreas, which were not detected by conventional POPS. LIMITATIONS: Because none of the patients in the 3 cases underwent surgical resection, a comparison to clarify total agreement between the preoperative POPS findings and the resected specimen was not possible. CONCLUSIONS: POPS with NBI may facilitate the observation of both fine mucosal structures and capillary vessels in patients with IPMN, although further study is necessary to fully establish the clinical benefit. [ABSTRACT FROM AUTHOR]

Abstract: Positronium time of flight (Ps-TOF) was measured by implanting slow positron pulses at variable energies into a nano-architectural silica thin film with two-dimensionally connected cage-like pores to investigate a continuity of the self-organized extremely thin diffusion barrier between the pores. By comparing a capped and open-pored low-k film, we found a Ps-TOF spectrum with positron implantation energy of 0.2keV that reflects the sample structure is consistent with an open pore fraction η <1.7·×10−6 of the diffusion barrier. [Copyright &y& Elsevier]

Abstract: Equivalent insulation test voltage at room temperature of high temperature superconducting (HTS) power apparatus with coil structure for power frequency withstand voltage tests is discussed based on medium factors of insulation weak parts in electrical insulation elements of the HTS power apparatus. Uniform and non-uniform field gaps, triple junction and solid insulator surface are selected as the insulation weak parts, and their medium factors are theoretically and experimentally calculated as the ratio of partial discharge (PD) inception or direct-breakdown voltages in liquid nitrogen or cryogenic nitrogen gas to those in atmospheric air at room temperature. The results show that the type of insulation weak part affects the relationships between the medium factor and the gap length between electrodes as well as the state of cryogenic surrounding medium. These medium factors are compared with the medium factor of a coil-to-coil insulation element of HTS pancake coils that contains some of the insulation weak parts, and it is verified that the medium factor of the coil-to-coil insulation element can be obtained by using that of triple junction or solid insulator surface. Finally, a selection method of a significant unique medium factor is discussed to determine the equivalent insulation test voltage at room temperature for the confirmation of the insulation reliability of all the parts of the HTS apparatus. [Copyright &y& Elsevier]

This paper deals with the determination method of the equivalent insulation test voltage at room temperature that secures the reliability of the cryogenic electrical insulation of the high temperature superconducting (HTS) power apparatus. The high voltage test is related to the apparatus with coil structure at the stages of its development, manufacturing and shipment. In the test method, the equivalent insulation test voltage at room temperature is derived from the standard test voltage at cryogenic temperature, based on the idea that the HTS power apparatus should be operated without partial discharges (PDs). The conversion factor between the two voltages is given by the product of the two medium factors, i.e. the one relating to the potential distribution along the coil winding and the other relating to the PD inception condition at the weakest part in the electrical insulation system. In order to determine the latter factor concerned with the non-linear phenomena against electrical stresses, the PD inception voltages at cryogenic and room temperatures are theoretically and experimentally estimated for modeled turn-to-turn insulation system. The results show that both estimated and measured values are in fairly good agreement and the proposed method is useful for the equivalent high voltage test at room temperature for the HTS power apparatus. [Copyright &y& Elsevier]

Abstract Cholangitis is a major complication following transplantation. We report a living donor liver transplant (LDLT) patient with cholangitis due to multiple stones in the intrahepatic bile duct during hepaticojejunostomy anastomosis, who was successfully treated with the rendezvous technique using double balloon endoscope. A 64-year-old woman underwent LDLT with right lobe graft and hepaticojejunostomy for Wilson disease. There was bile leakage with biliary peritonitis, which was treated conservatively after transplant. Two years after surgery, she developed reiterated cholangitis due to stenosis of hepaticojejunostomy anastomosis and multiple stones in the intrahepatic bile ducts. Percutaneous transhepatic biliary drainage was performed. The size of the drainage tube was increased, and the anastomotic area was dilated in a stepwise manner using a balloon catheter. The stones were crushed and lithotomy was performed using electronic hydraulic lithotripsy through cholangioscopy. Finally, lithotomy was performed for the remaining stones through endoscopic retrograde cholangiography with the rendezvous technique using the double balloon endoscope. Rendezvous approach with percutaneous transhepatic biliary drainage and double balloon endoscopic retrograde cholangiography was an effective treatment for the multiple intrahepatic stones in hepaticojejunostomy following LDLT with right lobe graft. [ABSTRACT FROM AUTHOR]

Aim: To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Materials and methods: Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Results: Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30min after exercise. Conclusion: Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles. [Copyright &y& Elsevier]

A new positron lifetime spectrometer has been constructed and tested. It consists of a state-of-the-art digital oscilloscope (LeCroy Wavepro 960) and scintillation detectors based on Hamamatsu H3378 (R2083Q) photomultiplier tubes and BaF2 scintillators. A very good time resolution is obtained with scintillators of commonly used sizes (28 mm in diameter, 10–20 mm thick) and wide energy window settings (40–50%). The time resolution of 144 ps full-width at half-maximum (FWHM) is achieved for the positron lifetime measurement, in which time differences are measured between the arrivals of a 1.27 MeV γ-ray from 22Na and one of the two positron annihilation γ-rays of 0.511 MeV. The time resolution is further improved with a ‘double-stop’ setup, where timing information carried by the positron annihilation γ-ray pair is combined to determine the time of the annihilation. The time resolution with this setup is 119 ps FWHM. This improvement is interpreted in terms of the energy deposit in the scintillation detectors by γ-rays. Applications of the new spectrometer to other scintillation timing measurements are also described. [Copyright &y& Elsevier]

An 8-MeV linear proton medical accelerator designed with a high RF duty operation is being developed at Ibaraki Neutron Medical Research Center for iBNCT (Ibaraki - Boron Neutron Capture Therapy). The reliability and stability of the cooling water control system has become one of the most important issues in realizing the medical application of the accelerator, which is designed considering high performance and low costs. However the previous cooling water control system with a commercial PID (Proportional–Integral–Differential) controller could not meet the operation requirements of the medical accelerator. Therefore, a new intelligent cooling water controller is successfully developed by application of Fast Feed-forward for Future (FFF). The detailed design of the intelligent cooling water control system and its great efficacy in improving accelerator operation is described in this paper. The stability of the cooling water temperature is improved greatly from the previous ± 0. 30 ° C to the current ± 0. 03 ° C. Moreover, the response time of cooling water control is decreased dramatically from the previous 5 min to approximately 20 s. Precise operation and an excellent auto-tuning of the RFQ (Radio Frequency Quadrupole LINAC) cavity are realized by using this stable and intelligent water control system. The beam transmittance is also improved slightly after a fine scan experiment with different settings of RF devices under stable acceleration operation. Finally, the RF startup time is also reduced by using this intelligent cooling water control system. Now the iBNCT accelerator operation is greatly improved with a very high reliability and stability. The accelerator will be operated as a practical medical therapy in late 2019. The technology developed in this intelligent cooling water control system will be very useful for the development of similar accelerators with high performance and low cost. [ABSTRACT FROM AUTHOR]

Abstract At Ibaraki Neutron Medical Research Center, an 8-MeV proton linear accelerator is being developed for iBNCT (Ibaraki - Boron Neutron Capture Therapy), with the aim of achieving the highest possible performance at a low cost. In this accelerator, there are two RF cavities driven by only one high-power klystron as the RF source. A digital low-level RF system has been successfully implemented for the iBNCT accelerator, with very good RF field regulation. An effective multipurpose and smart tuner controller was also developed. Finally, a novel auto-startup technology for two cavities with one RF source was successfully developed. The time required for the RF startup process is greatly reduced from the conventional time of 30 min, to less than 1 min. The good stability and fast response achieved by using this technology make it suitable for the medical use of iBNCT accelerators. This technology will be extremely useful in the development of similar accelerators. [ABSTRACT FROM AUTHOR]

In boron neutron capture therapy, it is important to evaluate the dose administered to a patient's body outside the tumour area. The exposure dose is evaluated by calculation; however, the calculated value must be validated using a measured value. The dose evaluations based on the measured neutron spectrum are investigated. Multi-foil activation, combined with a LiCaAlF 6 scintillation detector and an imaging plate, is proposed as a measurement method. The proposed method can measure the neutron spectrum at various points quickly. [ABSTRACT FROM AUTHOR]