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Funding Acknowledgements Type of funding sources: None. Background There are limited clinical studies on recurrent atrial fibrillation (AF) mechanisms after initial cryoballoon ablation (CBA). Purpose We aimed to elucidate the mechanisms of AF recurrence after CBA based on electrophysiological findings obtained during the second ablation and the response to treatment. Methods Of 885 patients who underwent CBA at our hospital between 2016 and 2022, 50 (5.7%) patients (age 68 ± 9.2 years, 62% male, 52 % paroxysmal AF, body mass index (BMI) 25 ± 3.8 kg/m2, left atrial diameter (LAD) 44 ± 5.9mm, left ventricular ejection fraction (LVEF) 66 ± 11%, CHADS2 score 1.9 ± 1.4) were included. All the patients were treated with an Arctic Front Advance™ in the initial CBA. Each pulmonary vein (PV) was treated with a target time of 180 sec. Routine left atrial roof line and posterior wall isolation was not created. However, tricuspid valve isthmus isolation (CTI) and superior vena cava (SVC) isolation were added as required. The findings obtained with the 3D-mapping system during the second ablation were analyzed. Furthermore, the contents of the second ablation and the clinical outcomes were investigated. Results The first ablation successfully isolated PVs in all patients, and additional radiofrequency ablations were CTI ablation in 28 patients and superior vena cava (SVC) isolation in 6 patients. The second ablation was done after 24±16 months. At recurrence, persistent AF was 24%. Furthermore, atrial flutter was recorded in 16% of the 50 cases. The 3D-mapping systems used for guidance were RHYTHMIA HDx™ in 42 cases, CART-XP™ in 5 cases and EnSite NavX™ in 3 cases. Electrical reconnection of PV was detected in 14 patients. They included seven left-superior PVs, two left-inferior PVs, two left-common PVs, four right-superior PVs and five right-inferior PVs. There were 11 cases of conduction only in the carina area, five with left-sided and six with right-sided. All second ablations were treated with high-frequency irrigation catheters. The treatments were PV re-isolation in 14 patients, isolation area expanding in 43 patients, SVC isolation in 24 patients, CTI ablation in 3 patients, and mitral isthmus ablation in 2 patients. After 24.8 ± 14.9 months, treatment outcomes were as follows; AF was completely cured in 23 patients, anti-arrhythmic drugs were required in 23 patients, and no effects in 4 patients. Comparing the completely cured patients’ group (23 patients) with the other (27 patients), age (65.1 ± 9.3 years vs 70.5 ± 8.6 years, p < 0.05) and CHADS2 score (1.5 ± 1.3 vs 2.3 ± 1.3, p < 0.05) have significant differences. There were no differences in the presence of PV reconnection, BMI, LAD, LVEF and second ablation contents. Conclusion In patients with recurrent AF after CBA, less than 30% had PV-reconnection, and its disappearance was not associated with AF disappearance. Non-PV foci, except SVC origin, might cause recurrent AF after CBA.

Background Molecular hydrogen (H2) has protective effects against ischemia-reperfusion injury in various organs. Because they are easier to transport and safer to use than inhaled H2, H2-rich solutions are suitable for organ preservation. In this study, we examined the protective effects of an H2-rich solution for lung preservation in a canine left lung transplantation (LTx) model. Methods Ten beagles underwent orthotopic left LTx after 23 hours of cold ischemia followed by reperfusion for 4 hours. Forty-five minutes after reperfusion, the right main pulmonary artery was clamped to evaluate the function of the implanted graft. The beagles were divided into two groups: control group (n = 5), and H2 group (n = 5). In the control group, the donor lungs were flushed and immersed during cold preservation at 4°C using ET-Kyoto solution, and in the H2 group, these were flushed and immersed using H2-rich ET-Kyoto solution. Physiologic assessments were performed during reperfusion. After reperfusion, the wet-to-dry ratios were determined, and histology examinations were performed. Results Significantly higher partial pressure of arterial oxygen and significantly lower partial pressure of carbon dioxide were observed in the H2 group than in the control group (P = .045 and P Conclusions Our results demonstrated that the H2-rich preservation solution attenuated ischemia-reperfusion injury in a canine left LTx model.

Amyotrophic lateral sclerosis (ALS) is a progressive debilitating neurodegenerative disease with a life expectancy of 3-5 years from initial symptoms. We report a case of ALS who received autologous adipose-derived mesenchymal stem cells (ADSC) and was followed up for 7 years.A 46-year-old man noticed weakness of his legs, difficulties on going down the stairs and coughing during eating in 2009. After complete workout, a diagnosis of ALS was confirmed. His ALS Functional Rating Scale-R (ALSFS-R) was 43. Symptoms rapidly progressed and he coughed and choked during eating. Starting in 2013, the patient received a total of six intravenous infusions of autologous ADSC. Changes in electromyogram, nerve conduction, and ALSFS-R were assessed.Soon after the administration, he noticed that he did not cough during conversation or eating food. Although he had difficulty in walking down the stairs, he remained well without coughing, dysarthria, or dysphagia. His ALSFS-R increased up to 45. Fascicular potentials were not detected in any muscles examined including trapezius muscle and rectus femoris muscles. The patient was well for 7 years after ADSC therapy by the time of this report and more than 10 years from the time of onset.The present case suggests that autologous ADSC can be administered safely and may be potentially useful in patients with ALS. Further investigations are warranted in order for the results to be generalized to other ALS patients.

BACKGROUND We have developed a novel method for native upper lobe–sparing living-donor lobar lung transplantation (LDLLT) to overcome a small-for-size graft in standard LDLLT with acceptable results. We hypothesized that grafts implanted with this procedure might work more efficiently than those in standard lobe transplantation. METHODS Bilateral LDLLT was performed in 31 patients with a functional graft matching of less than 60% at our institution between August 2008 and December 2015. Of these, 22 patients were available for evaluation of pulmonary function more than 1 year later: 15 undergoing standard LDLLT with less than 60% functional matching and 7 undergoing native upper lobe–sparing LDLLT. RESULTS Overall survival at 2 years was 87.5% in the lobe-sparing LDLLT patients and 79.0% in the standard LDLLT patients (p = 0.401). The median forced vital capacity size–matching levels were 50.7% ± 1.6% in the standard LDLLT and 45.2% ± 2.3% in the sparing LDLLT group (p = 0.074). The 1-year and 2-year post-operative volume ratios of inspiration to expiration were significantly different between the 2 groups, at 1.76 and 1.45 after standard LDLLT (p = 0.019) vs 2.41 and 2.23 after lobe-sparing LDLLT (p = 0.015). CONCLUSIONS The grafts in lobe-sparing LDLLT functioned more effectively than those in standard LDLLT. This advantage was associated with the improvement of pulmonary functions.

A 1280×960 floating diffusion storage global shutter image sensor is implemented in a 3D stacked back illuminated indirect time of flight sensor (iToF). The sensor, achieves 18,000e- full well capacity and 32% quantum efficiency (QE) with a pyramid surface for diffraction (PSD) structure [1], utilizing a 3.5µm pixel. Low power consumption is also achieved, due to low leakage current for the iToF pixel and low resistance Cu-Cu connection metal wiring. These device architectures enable high resolution and wide dynamic range 3D depth sensing for both near and far objects.

Background Geriatric nutritional risk index (GNRI) was developed as a “nutrition-related” risk index and was reported in different populations as associated with the risk of all-cause and cardiovascular morbidity and mortality. Purpose The purpose of this study was to assess the associations of GNRI with mortality and amputation free survival in patients with peripheral artery disease (PAD). Methods From January 2011 to June 2016, 295 consecutive patients (73.3±9.2 years; 75.6% male) with PAD undergoing endovascular treatment (EVT) in our hospital were retrospectively examined. The GNRI on admission was calculated as follows: 14.89 × serum albumin (g/dl) + 41.7 × body mass index (BMI)/22. Characteristics and mortality were compared between 2 groups: low GNRI ( Results The median follow up period was 39.4±26.4months. There were 85 deaths (28.8%) and 13 major amputation (4.4%) during the follow-up. Patients in the low-GNRI group were more often higher age, non-ambulatory state, hemodialysis and critical limb ischemia. BMI, serum hemoglobin, albumin, low-density lipoprotein were significantly lower, whereas serum C-reactive protein was significantly higher in the low-GNRI group than the high-GNRI group (P Conclusion The low GNRI is associated with an increased risk of mortality and limb events in patients with PAD. Amputation-free survival (Kaplan-Meier) Funding Acknowledgement Type of funding source: None

Background While it is generally accepted that cardiac autonomic nervous system (CANS) plays an important role in atrial fibrillation (AF) and pulmonary vein isolation (PVI) by radiofrequency catheter ablation modifies the ganglionated plexi (GP), the alterations of CANS after PVI are not clarified. Purpose The objective of this study was to investigate the alteration of CANS after conventional cryoballoon ablation (CBA) by using a non-invasive examination method of measuring resting heart rate (R-HR) and coefficient of variation of R-R interval (CVR-R) which is a representative parameter of heart rate viability. CVR-R reflects R-R interval variation affected by respiration. It is calculated from the R-R interval of consecutive 100 heart beats of sinus rhythm recorded at rest. Declines of CVR-R indicate the parasympathetic dysfunction and the normal range of it varies depend on the age. As age increases from 30s to 70s, the average value of CVR-R decreases from 4.0% to 2.4%. Methods Consecutive patients of paroxysmal AF treated with initial CBA in our institute participated. Subjects were limited to the patients who maintained sinus rhythm through the study and whose prescription had not been changed after procedure. All patients recorded 12-lead electrocardiogram to measure R-HR and CVR-R before and the day after the procedure. We compared R-HR and CVR-R of all patients before and after CBA. And in addition, we compared them in each of two groups whose pre-procedural H-RH were under 50 bpm (Group-U50) and over 70 bpm (Group-O70). All procedures were performed with second generation 28mm cryoballoon (CB)s under the conscious sedation with Dexmedetomidine. CB temperature was down to a minimum of -60°C and target application time was 180 seconds. Results In the procedure of all 105 patients (male gender, 54%; age, 66.9 ± 10.4years; CHADS2score, 1.15 ± 1.04; diabetes mellitus,14%; beta-blocker therapy, 16%), 1 of touch-up for PVI, 6 of supra vena cava isolation and 21 of cavotricuspid isthmus linear ablations with radiofrequency catheter were added. In all patients, R-HR increased from 58.9 ± 9.2bpm to 72.4 ± 9.5bpm (P Conclusions After CBA, R-HR increment and CVR-R decrement were significantly observed. CVR-R was halved regardless of pre–procedural R-HR. Damages to GP by CBA would be reflected as denervation of vagus nerves in CANS. R-HR increase might be associated with parasympathetic suppression of CANS.

Remaining lung tissue after pulmonary resection can expand without decline in structural complexity and compensate for functional loss, showing morphological and functional reserves. However, the distribution of these reserves is unknown. This study examined the heterogeneity of morphological and functional reserves of the remaining lung tissue.We retrospectively analyzed 53 donors who underwent right lower lobectomy for living-donor lobar lung transplantation. We examined morphometric changes in computed tomography images from 3 to 12 months after lobectomy. We assessed lung volume and structural complexity expressed as the fractal dimension. We also assessed effective lung volume (the volume of the lung with intermediate density) and volumetric fluctuation during respiration. Changes were compared between the right upper lobe, middle lobe, and left lung.The expansion of lung tissue was greater in the middle lobe (130.9% ± 19.7%) than in the upper lobe (109.7% ± 9.2%; P .001). The fractal dimension declined in the upper lobe (P .001) but was maintained in the middle lobe (P = .39). The increase in effective lung volume was larger in the middle lobe (97.2 ± 73.5 mL) than in the upper lobe (62.7 ± 87.1 mL; P .001), but not significantly different from that of the left lung (55.8 ± 186.3 mL; P = .052). A similar pattern was seen in respiratory fluctuation.Morphological and functional changes in lung tissue remaining after pulmonary resection were heterogeneous. The right middle lobe demonstrated morphological and functional reserves after right lower lobectomy.

A real-time data display and storage device was developed for neutron scattering experiments. The device contains two sets of field programmable gate arrays and onboard microcomputers for data display and storage. The developed device can determine the time-of-flight and time- resolved neutron position data with a time range from 0 to 40 ms using a beam of pulsed neutrons at 25 Hz. It was confirmed by an operation test using burst and continuous test pulses that the device exhibited a pulse pair resolution of less than 1 μs and a counting rate capability of more than 1 Mcps.

We have successfully improved the scaling of Cu-Cu hybrid bonding. In this study, 3 $\mu {\mathrm{ m}}$-pitch and 3M Cu-Cu connections with sufficient electrical properties and reliabilities were achieved. The ultra-fine pitch Cu-Cu connections correspond to the 0.75x scaling of conventional Cu-Cu hybrid bonding that we previously reported. Our high density 3D chip stacking technology is expected to enhance not only the function of back-illuminated CMOS image sensors (BI-CIS) but also that of coming 3D stacked semiconductor devices.

Purpose In lung transplantation, ischemia-reperfusion injury (IRI) plays a critical role in the development of primary graft dysfunction. Among cell deaths induced by IRI, regulated necrosis has been garnering much attention. Above all, necroptosis is well known, and there are some reports on necroptosis inhibition attenuated IRI improvement in solid organ transplantation. However, there are few reports about mixed lineage kinase domain-like protein (MLKL), which is proposed as a crucial mediator of necroptosis. The purpose of this study was to verify the hypothesis that the MLKL inhibitor necrosulfonamide, (NSA) attenuates IRI. Methods Male Lewis rats were heparinized and subjected to left thoracotomy under the anesthetization. Then, the left hilum was clamped for 90 min, followed by reperfusion for 120 min (rat hilar clamp model). NSA 0.5 mg and the solvent were intraperitoneally administered 30 min before ischemia in the NSA group and the vehicle group, respectively (n = 8, for both). After reperfusion, arterial blood gas analysis, physiological data (dynamic compliance, mean, and peak airway pressure), lung wet-to-dry weight ratio (W/D), and histological findings (extravascular red blood cell and neutrophil count and vascular edema) were evaluated under the right hilum occlusion. Results The NSA group had higher arterial oxygenation than the vehicle group (p = 0.0009). Dynamic compliance was higher and peak and mean airway pressures were lower in the NSA group than in the vehicle group (p = 0.0356, p = 0.0181, and p = 0.0394, respectively). W/D ratio was also significantly improved in NSA group (p = 0.0136). Histologically, hemorrhage and neutrophil in alveolar or interstitial space were significantly lower in the NSA group (p = 0.0357, p = 0.0157, respectively). Perivascular edema evaluated by vascular cuff was also ameliorated in the NSA group as well W/D ratio (p = 0.000155). Conclusion Our results suggested that NSA alleviated lung IRI via necroptosis inhibition in rat lung.

A novel ceramic-insulated detector element was developed for two-dimensional neutron measurement, and an irradiation experiment was performed using a Cf-252 neutron source. The element consisted of a ceramic insulator and a ball-shaped anode. It is estimated that a ceramic insulator can suppress the background noise caused by unintentionally scattered neutrons. An electrical field of 1.60×107 V/m was obtained based on a calculation at the top of the ball-shaped anode. Neutron signals were clearly observed using the detector element, thus validating its operation.

Neutron devices such as neutron detectors, optical devices including supermirror devices and 3He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.

Pacemaker mechanisms in the heart of the primitive crustacean Triops longicaudatus were examined electrophysiologically. The heart is tubular and the heart wall consists of a single layer of myocardial cells. No nerve cells were found in the heart, either with methylene blue vital staining or by light microscopy of serial sec- tions. The heart beats rhythmically at a frequency of 120 to 240 beats/min, and each beat is associated with a slow membrane potential change in the heart muscle. The am- plitude of the slow potential varies widely and no spikes appear on it. The heart muscle cells are electrically cou- pled with each other and generate synchronous slow po- tentials. No localized portion of the heart exhibited a frequency that always preceded the others. The muscle activity could be phase-shifted by injection of a single brief current pulse and could be entrained to a lower or higher frequency by repeated brief current pulses injected into the muscle cell. The frequency of muscle activity could be changed by the injection of DC current into the muscle cell, and the change in frequency was linearly related to the intensity of the current. When the intensity of hyperpolarizing DC current exceeded a certain value, the muscle activity disappeared abruptly, and the heart stopped beating completely. These results show clearly that the heartbeat of Triops is myogenic. The heart is diffusely myogenic and should be regarded as a single muscle oscillator.

Posterior reversible encephalopathy syndrome is a neurological complication associated with calcineurin inhibitors. There is no consensus regarding the continuation of calcineurin inhibitors in the event of posterior reversible encephalopathy syndrome. We report 3 cases of posterior reversible encephalopathy syndrome among 155 lung transplant recipients (1.9%). The calcineurin inhibitor trough level exceeded the therapeutic range in only 1 case. Our findings demonstrate that temporary cessation of calcineurin inhibitors and administration of basiliximab may be effective strategies for managing posterior reversible encephalopathy syndrome.

A neutron-sensitive ZnS/10B2O3 ceramic scintillator detector was developed as an alternative to a 3He-gas-based detector for use in a plutonium canister assay system. The detector has a modular structure, with a flat ZnS/10B2O3 ceramic scintillator strip that is installed diagonally inside a light-reflecting aluminium case with a square cross-section, and where the scintillation light is detected using two photomultiplier tubes attached at both ends of the case. The prototype detectors, which have a neutron-sensitive area of 30 mm×250 mm, exhibited a sensitivity of 21.7–23.4±0.1 cps/nv (mean±SD) for thermal neutrons, a 137Cs gamma-ray sensitivity of 1.1–1.9±0.2×10−7 and a count variation of less than 6% over the detector length. A trial experiment revealed a temperature coefficient of less than −0.24±0.05%/°C over the temperature range of 20–50 °C. The detector design and the experimental results are presented.

Purpose Lung transplantation is an effective therapy for end-stage patients with chronic respiratory failure due to various benign lung diseases. The organ shortage crisis is a serious problem, so it is required to develop alternative therapies. There have been reports of organ organoids ameliorating organ function but there have been few reports of lung organoids being capable of restoring respiratory function. We therefore hypothesized that immature mouse fetal lungs would ameliorate severe respiratory failure and connect the airways between recipient and donor lungs. Methods Lungs from the fetuses of pregnant GFP-C57BL/6 mice at 13.5 days gestation were injected into the left lungs of recipient mice. Severe lung injury was induced by paraquat, and we analyzed survival rate, pulmonary function, PaO2/FiO2, lung cytokine levels and pathohistological findings with light-sheet microscopy after 1 month. Results At 4 weeks after orthotopic implantation histopathological findings showed that there was no airway connection between recipient lung and immature fetal lungs of mice. However, hematoxylin and eosin staining showed reduced lung inflammatory cells, reduced lung edema, and active cell proliferation of fetal lung cells. Maximum airway pressures of the sham, vehicle and therapy groups (n=3, 1 and 6 respectively) were 8.91±1.47, 9.75, and 9.21±1.22 mmHg after one month. The airway compliance of the sham, vehicle and therapy groups were 0.041±0.017, 0.036 and 0.037±0.008 mmHg. The arterial partial blood pressures in the left ventricle of the sham, vehicle and therapy groups under FiO2 1.0 were 449±13.4, 516 and 427±28.4 mmHg. The survival rate of the therapy group increased from 5.9% to 39%, compared with that of the vehicle group (p=0.0338 by log-rank test). There was no difference of lung cytokine levels between the vehicle and therapy groups. The low number of mice and the high standard deviation affected the results of lung cytokine levels. The level of cytokines of some treated mice showed severe lung injury, however, other mice showed decreased cytokine levels. Conclusion Immature fetal lungs did not self-organize airway structures, however, they improved the survival rate of mice with paraquat-induced severe lung injury.

Purpose Molecular hydrogen (H2) has been reported as having protective effects on ischemia-reperfusion injury (IRI) in various organs. However, most of the reports are on inhalation of H2. Our group has previously reported the protective effects of H2-rich solution on lung IRI in a rat hilar-clamp model (Takahashi M, et al. Eur J Cardiothorac Surg 2017; 51: 442-448.) and the protective effects of hydrogen-rich preservation solution on lung preservation in a rat left lung transplant (LTx) model (Saito M, et al. J Heart Lung Transplant 2018; 37: S226). In this study, we examined the protective effects of hydrogen-rich preservation solution on lung preservation in a canine left LTx model. Methods TOYO beagles underwent orthotopic left LTx after cold ischemia followed by reperfusion (RP) for 4 hours. Forty-five minutes after RP, the right main pulmonary artery was clamped for evaluating the implanted graft function. Beagles were divided into two groups: control group (CON, n=4) and hydrogen group (H2, n=4). In the CON groups, donor lungs were flushed and immersed for 23 hours cold preservation at 4 °C by the preservation solution (ET-Kyoto Solution). In the H2 groups, donor lungs were flushed and immersed by the hydrogen-rich ET-Kyoto Solution. Arterial blood gas analysis, lung mechanics, and pulmonary vascular resistance (PVR) were evaluated during RP. After RP, wet-to-dry ratio (W/D) was evaluated. Results Compared with the CON group, significantly higher partial pressure of arterial oxygen (Figure A) and significantly lower partial pressure of carbon dioxide in the H2 group was observed 4 hours after RP. Although not statistically significant, dynamic lung compliance was better and PVR was lower in the H2 group than in the CON group (Figure B, C). Furthermore, W/D in the H2 group was significantly lower than that in the CON group (Figure D). Conclusion Our results indicated that hydrogen-rich preservation solution attenuated IRI in a canine left LTx model.

Purpose To evaluate the effects of pathogenic bacteria (PB) in the respiratory tract, we investigated perioperative airway pathogens of recipients and donors in living-donor lobar lung transplantation (LDLLT) and cadaveric lung transplantation (CLT). Methods Between Jun. 2008 and Sep. 2018, 193 lung transplants (LTxs) were performed at our institution. There were 85 LDLLTs involving 156 living donors, while there were 108 CLTs involving 104 brain-dead donors. We investigated PB in the respiratory tract of the recipients before LTx and within 1 month after LTx. Furthermore, we also investigated PB in the respiratory tract of the donors before LTx. Results In LDLLT, PB were found in 19 recipients (22.4%) before LTx, while PB were found only in 3 living donors (1.9%). In CLT, PB were found in 28 recipients (25.9%) before LTx and PB were found in 71 cadaveric donors (65.7%). There were no recipients who died of the infectious disease caused by PB derived from donors. The existence of PB both in recipient and donor (R+/D+) showed the worst survival, but there was no significant difference in comparison with other groups (R+/D-, R-/D+, R-/D-, Fig. 1). Of note, quite a few PB, which were derived neither from recipients nor donors, was detected in the recipient's airway within 1 month after LTx. PB was found from sputum culture in 45 recipients (52.9%) in LDLLT and in 50 recipients (46.2%) in CLT, respectively. However, no recipients died of infection caused by newly detected PB after LTx. On the other hand, patients whose PB was not found postoperatively had a better 5-year survival compared to patients whose PB were found (76.2% vs. 63.9%, p=0.031: Fig. 2). Conclusion Graft lungs of living donors were significantly cleaner than those of cadaveric donors microbiologically. Regardless of LDLLT or CLT, respiratory tract of the recipients were exposed to a variety of PB derived from neither donors nor recipients. Although PB were not the cause of death in early time after TLx, PB may influence long-term clinical course.

A multiwire-type two-dimensional neutron detector system with a sensitive area of 128×128 mm 2 is developed for use in the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex. The system can achieve a short response time and high spatial resolution using the individual line readout method. Optical devices have been incorporated in the system for long-distance signal transmission and insulation between a detector head in the neutron shielding and signal processing circuits in the data acquisition room. The detector system exhibits a pulse-pair resolution of 1 μs, an average spatial resolution of less than 2 mm full width at half-maximum in the sensitive region, and a two-dimensional homogeneity of 8.3% in all pixels.

A scintillator-based gamma-ray detection system that uses a radiation-resistant optical fiber was developed. The system consisted of two radiation-resistant optical fibers—one, a fiber with a scintillator, and the other, a fiber without a scintillator—which were used to obtain the gamma-ray dose rate at the measurement point. This system demonstrated a linear response with respect to the gamma-ray dose rate from 0.005 to 1.5 Gy/h and a good radiation resistance over an absorbed dose of more than 300 kGy.

A ceramic-insulated ball-anode (CiB) element that consists of a ceramic insulator, cathode lines, ball-shaped anodes, and anode lines was developed, and an irradiation experiment was performed using a Cf-252 neutron source. An electric field simulation of CiB element was conducted and strong electric fields of more than 107 V/m was obtained by the calculation using the finite element method. The neutron-induced signals of all pixels were observed using 8 × 8 ch small-sized test element under Cf-252 neutron irradiation.

Background. Early diagnosis of unilateral chronic lung allograft dysfunction (CLAD) is difficult because the unaffected contralateral lung functions as a reservoir in bilateral living-donor lobar lung transplantation (LDLLT). We previously reported the usefulness of 133Xe ventilation scintigraphy for detection of unilateral change, but the supply of 133Xe has been stopped globally. The present study aimed to examine the usefulness of inspiratory and expiratory computed tomography (I/E CT) volumetry for detection of unilateral change in CLAD patients. Methods. This was a retrospective single-center, observational study using prospectively collected data. A total of 58 patients who underwent bilateral LDLLT from August 2008 to February 2017 were analyzed. Respiratory function tests, I/E CT were prospectively conducted. ΔLung volume was defined as the value obtained by subtracting expiratory lung volume from inspiratory lung volume. Results. Fourteen (24%) cases were clinically diagnosed with CLAD, of which 10 (71%) were diagnosed as unilateral CLAD. ΔLung volume of bilateral lungs strongly correlated with forced vital capacity (r = 0.92, P < 0.01) and forced expiratory volume in 1 second (r = 0.80, P < 0.01). Regardless the phenotypes (bronchiolitis obliterans syndrome or restrictive allograft syndrome) of CLAD, Δlung volume onset/baseline significantly decreased compared with that in the non-CLAD group. Among the 10 unilateral CLAD patients, 3 with clinically suspected unilateral rejection yet did not show a 20% decline in forced expiratory volume in 1 second. In 2 of these, Δlung volume of unilateral lungs on the rejection side decreased by 20% or more. Conclusions. Our findings suggest that I/E CT volumetry may be useful for assessment and early diagnosis of unilateral CLAD after bilateral LDLLT.

A neutron-detection element using circular cathode bumps was developed for two-dimensional neutron measurement, and an irradiation experiment was performed using a Cf-252 neutron source. The element has triangularly arranged small-sized circular cathode bumps, and the bumps are linked together in the x- and y-directions for the detection of incident neutrons. Preliminary irradiation experiments for the developed element were performed using a neutron-detection system consisting of a pressure vessel, amplifier-shaper-discriminator boards, optical signal transmission devices, position encoders, and a data acquisition device. The element was arranged in the pressure vessel with a fill gas of composition He/(15%)CF4 at 0.7 MPa. The detector system exhibited a two-dimensional uniformity with a response of 10.1%. The average intrinsic spatial resolution was 1.89 mm full width at half maximum in the sensitive region, calculated by taking into account the track lengths of the secondary particles.

A gas-based neutron detection system with individual readout method and comprising a micro-pixel detector head was constructed, and preliminary experiments were conducted under neutrons irradiation. The detection system also consisted of a micro-pixel detector head, a gas chamber that had feedthrough lines of 541 channels, amplifier-shaper-discriminator boards, position encoders with field programmable gate arrays, and a device capable of fast data acquisition. The micro-pixel detector head exhibited a fast response time, and the full width at half maximum of the response time was 160 ns. Its gas gain was about 50 at an anode-cathode voltage of 560 V and a gas pressure of 0.5 MPa (0.45 MPa for He and 0.05 MPa for CF 4 ). Signal pulse peaks of neutrons could be identified and their output voltages at an anode and a cathode were 2.4 and 5.3 mV, respectively; on the other hand, the output voltage of all the anodes was 105 mV. The neutron detection system could easily distinguish neutron signals from the background noise, and the gas gain of the micro-pixel detector head did not changed.

A gas-based neutron imaging detector with individual read-outs with high spatial and temporal resolutions was developed for thermal neutron scattering experiments. The compact detector comprises a gas vessel that can withstand 11 atm, which feeds 541 signal lines to multichannel signal amplifier boards located close by to ensure a high signal-to-noise ratio and fast detector response. The performances of prototype detectors employing multiwire (MW) and microstrip (MS) detector heads were evaluated using a collimated cold-neutron beam. The MW detector system, which has a sensitive area of 40×40 mm2 with a wire pitch of 1 mm in each dimension (40×2 channels of read-outs), exhibited an average spatial resolution of 1.5 mm for 6.8-atm helium with 1.2-atm CF4. The MS detector system, which has a sensitive area of 51×51 mm2 with a strip pitch of 0.4 mm in each dimension (128×2 channels of read-outs), exhibited an average spatial resolution of 1.1 mm under the same gas conditions. The developed detector system exhibited position sensitivity that was linear to within 1% and a pulse-pair resolution of less than 1 μs.

Cyclic-tension fatigue of aluminum alloy, Al-4Cu-1Mg, was determined by an analysis of diffracted SH and SV waves, passing through the surface and reflecting the bottom of the specimen, respectively. The propagation time of SH waves and the internal friction of SV waves begins to decrease and increase from fatigue damage ratio (¼ N=Nf ) of 0.5, respectively, suggesting noticeable increase of movable dislocation. From the analysis of SH waves along the direction to the loading axis, the damping ratio decreases and the phase advances with increasing of the degree of fatigue. Assumed from SH wave flux model, the former behavior correlates well with increasing of the residual stress by cyclic tension. The latter may be characterized by viscoelasticity. These results show that ultrasonic transmission method is useful probe for evaluation of fatigue in aluminum alloy. [doi:10.2320/matertrans.48.550]

A two-dimensional gas-based neutron detector system that can be operated under high-pressure was developed, and an irradiation experiment was performed using a Cf-252 neutron source. The signals from neutrons clearly observed and can be discriminated from background signals such as gamma-ray and electrical noises. The flat-field image showed good homogeneity and an average gain spread of approximately 7.7%. The system exhibits a gamma-ray sensitivity of 1.1 × 10−7.

We have been developing a two-dimensional microstrip gas chamber for neutron scattering experiments such as reflectometer and small-angle neutron scattering for the intense pulsed neutron source at JSNS. Our detection system comprises a gas vessel that can operate up to 10 atm, four amplifier-shaper-discriminator boards that provide 128 × 128 individual readouts, an encoding system to determine neutron incident positions, and a data display device. The developed system digitally calculates the incident position of a neutron as the centroid of the “hit-channels” to ensure fast neutron counting and imaging. To examine the performance of the developed detector system, the total range of the secondary particles emitted by the nuclear reaction between neutrons and 3He nuclei was evaluated by irradiating a detection area of 5 × 5 cm 2 under the gas condition of 6.6-atm helium (partial pressure of helium-3 is 0.5-atm, the rest is helium-4) with 1.4-atm CF4. We confirmed that the measured hit-channel distribution agreed with the Monte Carlo-simulated results. The detector exhibited a spatial resolution of 1.5 mm in each axis direction, as measured using the collimated cold-neutron beam.

We have been developing a Micro-Strip Gas Chamber (MSGC) with individual readouts for neutron scattering experiments. Performance requirements of a two-dimensional position sensitive neutron imaging detector for detecting an accurate Bragg-peak from a sample target include high spatial resolution, high detection efficiency, fast temporal response, and low gamma-ray sensitivity. To meet these specifications in addition to achieving a compact size in spite of the multi-channels in the gas based detector, we constructed a detector system that has a gas vessel with 541 channel feedthrough directly connecting to the data processing circuits. The developed detector system exhibited a pulse pair resolution of less than 1 mus, a spatial resolution of about 0.8 mm in full width at half maximum and good agreement between the position of incident neutron and measured peak position

We evaluated the neutron-detection performance of a capillary plate under high-pressure 3 He in terms of the gas gain and the distribution of pulse heights, with the aim of using the device as a neutron detector and a gas preamplification device. The capillary plate exhibited a gas gain of more than 1000 up to a gas pressure of 6 atm. with a 5% mixture of ethane, confirming an adequate gas gain as a neutron detector. It was also found that the pulse shape of the induced-signal pulses were correlated with the emission angle of the secondary particles, protons and tritons, thereby providing useful information for developing a system with position-sensitive readouts with a high spatial resolution and a low background.

The microstrip gas chamber (MSGC) with an individual read-out and using two-level discriminators for each strip is proposed for neutron detection with a high spatial resolution. The system identifies secondary particles—protons and tritons—created in the nuclear reaction 3 He+n→p+T based on the difference in their track lengths, and determines the incident position of neutrons using suprathreshold signals from tritons. The new system selects the appropriate suprathreshold signals for proper identification from two-level discriminators according to the emission angles of the secondary particles. The calculated spatial resolution of the detector system using the two-level discriminators (Hi-InSPaD) was 0.5 mm in full width at half maximum when the MSGC was operated in a gas condition of a mixture of 20% argon with helium-3 at 0.5 MPa, when the strip pitches were 0.4 mm in both x and y axes. The calculated spatial response of the detector to the point-incident neutrons was superior to a standard InSPaD system that uses one level of threshold discrimination, in terms of the peak counts (about twofold higher) and the peak shape and width.

A microstrip gas chamber (MSGC) with a capability of track discrimination for neutron detection was developed whilst ensuring the stability of the MSGC and fulfilling the specifications required for detectors used in high-flux reactors and high-intensity pulsed-neutron sources. The developed two-dimensional detector system comprises an MSGC with individual signal channel read-outs and a new instrument system with a capability of secondary-particle discrimination (InSPaD). The InSPaD identifies the particles—proton and triton—created in the nuclear reaction 3He+n→p+T by a simple, fast and cost-effective method using the difference in the track length, and it allows using a small amount of heavy gas such as C2H6 with helium-3 as the filling gas for achieving a high spatial resolution. We describe the concept and design of the developed detector system and show some basic experimental results supporting the feasibility of the detector system with the InSPaD, including the gas gain of the MSGC, spatial uniformity of the gas gain, and pulse-height distribution along the tracks of the secondary particles created in neutron events.

A new instrument system with the capability of secondary-particle discrimination (InSPaD) was studied for the development of two-dimensional (2D) neutron detectors (NDs) filled with helium-3 gas and with high spatial resolution. The InSPaD can discriminate between tracks of a proton and a triton created in the nuclear reaction 3He(n,p)T by simply setting the level of the discriminator appropriately in each signal channel, and the system exhibits a high spatial resolution, high counting rate, low background, and stability. The InSPaD identifies the tracks of a proton and a triton on the basis of the length of the tracks, identifies the secondary particles, and calculates the incident positions of neutrons accurately in real time. Simulations of the 2D ND equipped with InSPaD revealed spatial resolutions of 0.46 mm in full width at half maximum for a 10% mixture of C2H6 with helium-3 at 0.3 MPa, and of 0.52 mm for a 20% mixture of argon with helium-3 at 0.5 MPa. The simulated results of the ranges of second...

A micro-strip gas chamber (MSGC) has been under development as a two-dimensional position sensitive detector for neutron scattering experiments at the high-intensity proton accelerator facilities. The MSGC requirements as a neutron detector are high counting rate, high detection efficiency, high positional resolution, stability and large area coverage. The purpose of this paper is to verify the properties of Gadolinium as a MSGC converter. The arrangements of a capillary plate and MSGC gas pressure have been optimized by simulation of a Gadolinium converter. As a result of that, a position resolution of 160 μm and n/γ ratio of 200 were obtained at the gas pressure of 0.02 atm. In view of γ-ray sensitivity, the further improvement is required for practical applications.