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Cigarette smoking, alcohol consumption, and Lugol-voiding lesions (LVLs) are the major causative risk factors of esophageal squamous cell carcinoma (ESCC); however, reports on ESCC cases unrelated to these risk factors are very limited. Here, we investigated the clinicopathological features and etiology of such cases. We retrospectively analyzed 704 consecutive superficial ESCC tumors of 512 patients who were treated with endoscopic submucosal dissection. The enrolled patients were divided into two groups—the very low-risk (VLR)-group and risk (R)-group—based on the presence of the abovementioned risks. Clinical, endoscopic, and pathological characteristics and genetic findings were assessed in both groups. The VLR-group consisted of 21 (4.1%) patients, who were characteristically female. Patients in the VLR-group presented gastroesophageal reflux disease (GERD), hiatal hernia, and non-open-type atrophic gastritis, and were negative for Helicobacter pylori. We found unique endoscopic features—frequently observed in the posterior wall of the middle thoracic esophagus—with a linear shape that closely resembled the erosion-like form of GERD. Additionally, histopathological examination showed that these tumors presented atypical nuclei limited to the basal and parabasal layer, sequential to the surrounding changes that presented pathological chronic inflammation of esophagitis. Evaluation of somatic mutations in cancer-related genes using next-generation sequencing revealed that the positive carcinogenic potential (TP53 mutation) of the tumors was relatively frequent in the VLR-group. Our study suggests that ESCC without major causative factors is related to GERD, with no remarkable oncogenic difference.

Superficial nonampullary duodenal epithelial tumors (SNADETs) have become frequently detected and referred for endoscopic resection (ER). However, optimal treatment methods and long-term outcomes after ER of SNADETs have not been fully elucidated. We aimed to clarify them by analyzing our large cohort of patients with SNADETs.We enrolled 190 consecutive tumors from 189 patients undergoing ER between January 2004 and September 2019. Cases were stratified into endoscopic submucosal dissection (ESD), conventional endoscopic mucosal resection, (CEMR) and underwater endoscopic mucosal resection (UEMR). Baseline characteristics and short-term outcomes were compared between the groups. Long-term outcomes were also investigated with a median follow-up of 36 months.ESD significantly exceeded CEMR (96.4% vs. 52.9%;While tumors ≤10 mm seem to be good indications for endoscopic mucosal resection, ESD should be considered for larger tumors to better achieve complete resection. Patients with submucosal invasive carcinomas have a great risk of cancer death. Therefore, a close follow-up and an additional treatment are desirable.

BACKGROUND Postoperative delayed bleeding (PDB) after gastric endoscopic submucosal dissection (ESD) is the most common adverse event in patients receiving antithrombotics even with second-look endoscopy. Moreover, with the increasing prevalence of cardiovascular and cerebrovascular diseases in an aging population with associated lifestyle-related diseases, an increasing number of patients receive antithrombotics. Several attempts have been made to prevent PDB in aging population; however, a consensus has yet to be reached. AIM To examine the efficacy of third-look endoscopy (TLE) for PDB prevention. METHODS One hundred patients with early gastric neoplasms receiving antithrombotics were prospectively enrolled and subjected to ESD with TLE between February 2017 and July 2019. The primary endpoint was PDB rate, which was compared with our preset threshold. Furthermore, we divided the bleeding period into early-and late-onset PDB (E-PDB and L-PDB, respectively) and analyzed its rate. As a secondary analysis, we compared PDB rates with those of a historical control group, using propensity score matching, and calculated the PDB rates per antithrombotic agent use in each group. RESULTS In total, 96 patients and 114 specimens were finally evaluated. The overall PDB rate was 7.9% (9/114) [90%CI: 4.7-13.1, P = 0.005], while the late-and early-onset PDB rates (L-PDB and E-PDB) were 5.3% [90%CI: 2.7-9.9, P < 0.0001] and 2.6% [90%CI: 1.1-6.4, P = 0.51], respectively. Propensity score matching generated 58 matched pairs for TLE and control groups. No differences were found in overall PDB incidence (10.3% vs 20.7%, P = 0.12), whereas L-PDB occurrence significantly differed (5.2% vs 17.2%, P = 0.04) between groups. Considering antithrombotics’ use, the overall PDB rate was higher for direct oral anticoagulants and multiple antithrombotics in the control group, while L-PDB incidence was lower in the TLE group for these agents (8.7% vs 23.1% and 5.0% vs 29.4%, respectively). CONCLUSION TLE for gastric ESD reduces overall PDB, and especially L-PDB incidence, among patients receiving antithrombotics.

OBJECTIVES Clinicopathologic characteristics and treatment outcomes of mixed-histological-type (MT) early gastric cancers (EGCs) treated with endoscopic submucosal dissection (ESD) have not been sufficiently elucidated. We aimed to clarify them in comparison with pure-histological-type EGCs. METHODS We used 3022 consecutive EGCs in 2281 patients treated with ESD from our prospectively maintained database. Cases were stratified into four groups according to the final diagnosis of the resected specimen are as follows: 2780 pure differentiated-type (DT), 127 DT-predominant MT (D-MT), 87 pure undifferentiated-type (UDT), and 28 UDT-predominant MT (U-MT). Clinicopathologic characteristics and treatment outcome were compared between pure DT and D-MT, and between pure UDT and U-MT separately. Risk factors for deep submucosal invasion, lymphovascular invasion, and a final diagnosis of MT were identified using multivariate analysis. RESULTS Both D-MT (41.7 vs. 92.0%; P

Objective This study compared the clinicopathological features and treatment outcomes of patients with primary early gastric cancers (EGCs) who had undergone Helicobacter pylori eradication and endoscopic submucosal dissection (ESD) with those of patients who were H. pylori-positive and had undergone ESD. Additionally, we investigated the incidence of metachronous cancer in these patients. Methods We retrospectively analyzed 1849 EGCs in 1407 patients who underwent ESD whom 201 primary EGCs were detected after H. pylori eradication (eradication group) and 1648 primary EGCs were detected in patients infected with H. pylori (infection group). We evaluated the clinicopathological features and treatment outcomes of the first ESD. We next divided 938 patients whose follow-up periods were >1 year into three groups, an eradication group (n = 61), an infection group (n = 562), and an eradication after ESD group (n = 315). The groups' cumulative metachronous occurrence rates were determined. Results The eradication group's median tumor size was significantly smaller, and the tumors were significantly more likely to be flat/depressed than those in the infection group. The groups did not differ regarding the treatment outcomes. The cumulative incidence of metachronous cancer was significantly higher in the eradication group than in the eradication after ESD group (P = 0.0454) and in the infection group than in the eradication after ESD group (P = 0.0233). Conclusion The treatment outcomes for EGC in the eradication group were favorable. The higher incidence of metachronous cancer in the eradication group suggests that careful endoscopic follow-up examinations are required.

Clinicopathological features of early gastric cancers arising in Helicobacter pylori uninfected patients

Thrombotic microangiopathy (TMA) is a serious complication following kidney transplantation. Although intestinal TMA is a major organ injury and causes abdominal pain, diarrhea and bloody stools, the clinical and endoscopic characteristics of small intestinal TMA remain unclear. Here, we report a drug-induced small intestinal TMA, which did not meet the laboratory-defined TMA criteria but was diagnosed by balloon-assisted enteroscopy (BAE). A 32-year-old woman who underwent kidney transplantation at the age of 10 years complained of abdominal pain, diarrhea and bloody stools one month after starting everolimus (EVE) as an immunosuppressant. Although she did not meet the diagnostic criteria for TMA serologically, BAE revealed a circumferential ulcer in the jejunum, and the pathological findings of a biopsy specimen showed microvascular thrombi, compatible with intestinal TMA. Her symptoms improved upon the discontinuation of EVE, demonstrating that EVE can cause drug-induced intestinal TMA. The present case suggests that BAE should be performed when abdominal pain, diarrhea, and bloody stools occur in patients receiving immunosuppressive medication following kidney transplantation, even if there is no evidence of TMA according to the laboratory definition.

Background In chronic lateral ankle instability (CLAI), the instability of the ankle joint results in repeated microtrauma to the articular cartilage. How the lesion condition or stage is affected by the presence of lateral instability in medial osteochondral lesions of the talus (OLT) is unclear. We aimed to examine whether CLAI is associated with the size and staging of medial OLT on radiographs, magnetic resonance (MR) images, and arthroscopy. Methods Forty-five patients with medial OLTs in 45 ankles were reviewed. Radiographs were assessed for damage and lesion classification. The tibio-talar tilting angle (TTA) was measured. The patients were divided into two groups: the CLAI group and the stable group. The lesion classification on radiographs, MR images, and arthroscopy, and size on MR images were statistically compared. Results The CLAI group had a mean TTA of 8.15 ± 3.41°, whereas the stable group had a mean TTA of 2.24 ± 1.64°. The CLAI group had a lower clinical score than the stable group at the initial visit to our clinic. The CLAI group presented with lesions of significantly shorter longitudinal and transverse diameters. Stages of medial OLT on radiographs, MR images, and arthroscopic evaluation were earlier in the CLAI group than those in the stable group. Conclusions Patients with CLAI presented in the early stages of OLT and had significantly smaller lesions than those without CLAI. The patients without CLAI may be selected for surgery at an early phase.

Introduction Calcaneal pitch angle and Meary’s angle are commonly used to assess longitudinal foot arches on lateral-view radiographs. However, the methods used to obtain the talar, first metatarsal, calcaneal, and plantar axes differ across multiple reports, and no study has evaluated the reproducibility of these approaches. The aim of this study was to determine the most reproducible methods for radiographically evaluating longitudinal axes. Methods Standing radiographic images of 40 feet from 21 consecutive outpatients were obtained to measure longitudinal axes of the talus, first metatarsal, calcaneus and plantar surface, which were defined using six, five, four and three different methods, respectively, selected from previous reports. Intraobserver and interobserver correlation coefficients were calculated. Results The best intraobserver and interobserver correlation coefficients for the talar, first metatarsal, and calcaneal axes were obtained using methods involving a line bisecting the angle formed by the lines tangential to the superior and inferior margins of the talus, a line connecting the centre of the first metatarsal head and the midpoint of the visualized base of the first metatarsal, and a line drawn tangential to the inferior surface of the calcaneus, respectively. For the plantar axis, a method that used the horizontal plane (as a reference axis) was regarded as the best approach, although intraobserver and interobserver correlation coefficients could not be calculated because all values were zero. Conclusions The aforementioned methods were considered to be optimal for the radiographic assessment of longitudinal foot arches. This study could contribute to more accurate assessments of foot deformities.

BACKGROUND AND AIM Endoscopic resection is feasible for superficial tumors in patients with ulcerative colitis; however, endoscopic resection options have not been evaluated comprehensively. We evaluated the efficacy and safety of endoscopic submucosal dissection and endoscopic mucosal resection, and decision making regarding endoscopic resection options for patients with ulcerative colitis. METHODS Endoscopically treated tumors from patients with ulcerative colitis were analyzed retrospectively. We evaluated en bloc and R0 resection, adverse events, local tumor recurrence, and metachronous lesion occurrence rates. RESULTS We examined 102 tumors (mean size, 12 mm; non-polypoid, 55 tumors) from 74 patients with ulcerative colitis, of whom, 39 and 63 underwent endoscopic submucosal dissection and endoscopic mucosal resection, respectively. The R0 resection rate was significantly higher for endoscopic submucosal dissection (97%) than for endoscopic mucosal resection (80%) (P = 0.0015). For 11-20-mm tumors, the R0 resection rate was significantly higher for endoscopic submucosal dissection (94%) than for endoscopic mucosal resection (55%) (P = 0.0027); the endoscopic submucosal dissection and endoscopic mucosal resection R0 rates did not differ for ≤ 10-mm tumors. The non-polypoid tumor R0 resection rates were significantly higher for endoscopic submucosal dissection (100%) than for endoscopic mucosal resection (65%) (P

BACKGROUND The undifferentiated-type (UDT) component profoundly affects the clinical course of early gastric cancers (EGCs). However, an accurate preoperative diagnosis of the histological types is unsatisfactory. To date, few studies have investigated whether the UDT component within mixed-histological-type (MT) EGCs can be recognized preoperatively. AIM To clarify the histopathological characteristics of the endoscopically-resected MT EGCs for investigating whether the UDT component could be recognized preoperatively. METHODS This was a single-center retrospective study. First, we attempted to clarify the histopathological characteristics of the endoscopically-resected MT EGCs with emphasis on the UDT component. Histopathological examination investigated each lesion’s UDT component: (1) Whole mucosal layer occupation of the UDT component; (2) UDT component exposure to the surface of the mucosa; and (3) existence of a clear border between the differentiated-type and UDT components. Then, preoperative endoscopic images with magnifying endoscopy with narrow-band imaging (ME-NBI) were examined to identify whether the endoscopic UDT component finding was recognizable within the area where it was present in the histopathological examination. The preoperative biopsy results and comparative relationships between endoscopic and histopathological findings were also examined. RESULTS In the histopathological examination, the whole mucosal layer occupation of the UDT component and exposure of the UDT component to the mucosal surface were observed in 67.3% (33/49) and 79.6% (39/49) of samples, respectively. A clear distinction of the border between the differentiated-type and UDT components could not be drawn in 65.3% (32/49) of MT lesions. In the endoscopic examination, the preoperative endoscopic images showed that only 24.5% (12/49) of MT EGCs revealed the UDT component within the area where it was present histopathologically. Histopathological UDT predominance was the single significant factor associated with the presence of the endoscopic UDT component finding (61.5% vs 11.1%, P = 0.0009). Only 26.5% (13/49) of the lesions were diagnosed from the pretreatment biopsy as having a UDT component. Combined results of the pretreatment biopsy and ME-NBI showed the preoperative presence of the UDT component in 40.8% (20/49) of MT EGCs. CONCLUSION Recognition of a UDT component within MT EGCs is difficult even when pretreatment biopsy and ME-NBI are combined. Endoscopic resection plays a significant role in both treatment and diagnosis.

A TE31,11 mode gyrotron has being developed to improve the output power for the ITER electron cyclotron (EC) system. Strong mode competition having counter-rotating modes in both the high and/or low field sides is, in general, the typical issue for high order mode oscillations. Active anode voltage control and beam radius control were introduced to overcome this issue and obtain stable 1 MW oscillation. The TE31,11 mode was oscillated in a hard-self excitation region and the efficiency was improved up to 50%. Long pulse operation of output power of 1 MW with total efficiency of 46% for 230 s was also performed. Oscillations of over–1 MW power of 1.1 MW and 1.2 MW for 2 s pulse were achieved.

A new fast directional switch for high power millimeter waves without frequency modulation was proposed. The principle is a triangle ring resonator of circular corrugated waveguides with a vibrating reflector. The switching frequency was obtained up to 300 Hz by a single vibration reflector. The deformed waveforms of the output powers were observed at large amplitude vibrations of a reflector.

For successful tokamak operation with adequate mode selection of the electron cyclotron wave, launching wave polarization should be accurately controlled. In this study, a new method is proposed to efficiently identify the response of polarizers using a geometric approach in the Stokes space, focusing on the fact that polarization can be represented as a vector in Stokes space and the response of a polarizer can be described as a rotation. The proposed methods are intended (i) to determine the response parameters of a polarizer or (ii) to determine the response parameters of two polarizers simultaneously. A simple measurement system was prepared to observe the polarizers’ output polarization in the 110/138 GHz transmission line. The determined response parameters of two polarizers can reproduce measured polarizations with sufficient accuracy above 99%. The direction of an output polarization circularity, the only feature of a polarization that could not be directly known from the prepared measurement, could also be determined with sufficient accuracy.

Background and Aims Colorectal neoplasms with submucosal fibrosis are the most challenging targets of endoscopic resection. Water pressure endoscopic submucosal dissection (WP-ESD) is a recently introduced procedure that has several advantages over conventional endoscopic submucosal dissection (C-ESD). This study aimed to assess the efficacy and safety of WP-ESD for fibrotic colorectal neoplasms. Methods This retrospective observational study investigated 133 colorectal neoplasms expected to have submucosal fibrosis that were resected by WP-ESD or C-ESD between April 2012 and April 2020. Eighty-seven lesions after endoscopic or surgical treatment, 18 with biopsy scar with fold convergence and 28 in patients with ulcerative colitis, were included. The differences in treatment outcomes, including procedure time and adverse event proportions, between the WP-ESD and C-ESD groups were analyzed. The clinical course after perforation using WP-ESD was also evaluated, including postprocedural multidetector CT findings obtained immediately after WP-ESD. Results Severe submucosal fibrosis was observed in 96 lesions (72.2%). The median procedure time was significantly shorter in the WP-ESD group than in the C-ESD group (43.5 minutes [interquartile range {IQR}, 32.8-73] vs 72 minutes [IQR, 45-105]; P = .0041). The multivariate analysis revealed WP-ESD as an independent factor for a short procedure time (odds ratio, 2.90; 95% confidence interval, 1.28-6.55). The proportions of post-ESD electrocoagulation syndrome (11.6% vs 13.1%) and perforation (20.4% vs 22.8%) were similar between the groups. Four of 11 patients with perforation who underwent WP-ESD showed fluid collection on postprocedural multidetector CT images. Conclusions WP-ESD can shorten procedure time for treating fibrotic colorectal neoplasms.

A diplexer to be used as a fast switching device of high power millimeter wave for an electron cyclotron current drive system has been developed. The operation frequency of the device is tunable by controlling the thermal expansion of the cavity using a precision chiller. The tunable range of the diplexer is about 225 MHz at the frequency band of 170 GHz. The temperature dependence of the resonant frequency shift in the ring resonator diplexer is −3.4 to −3.9 MHz/K, which agrees with the theoretical prediction. The switching operation is confirmed up to rf power of 260 kW, a pulse duration of 100 ms, and a frequency of 170 GHz.

The ITER EC system includes both an equatorial port launcher and upper port launchers as RF power injection devices, The waveguide switch in the transmission line (TL) is used to select the operating launcher. Its operation is required even during plasma operation, primarily for the mid-pulse switch operation. Changing the waveguide switch requires that the gyrotron stop RF power during the switch operation since the direction is changed by mechanical movement of the mirror position which takes a few seconds. Since the ITER EC system is based on a multi-subsystem concept, each subsystem has its own subsystem control unit (SCU). The EC main controller supervises all subsystem controllers. Hence, cooperative operation requires the sharing of the information of both RF power status and switch status between the gyrotron SCU and TL SCU via the main controller. Since the design of the inter-subsystem control scheme is a key issue for ITER EC system control, its evaluation is required. At QST, the gyrotron and ITER-relevant TL test stand were utilized for demonstration of mid-pulse switch operation. For this purpose, SCUs for each subsystem and the main controller were developed using the ITER-relevant control system. The operation of the mechanical switch during gyrotron pulse was demonstrated. During the 150 s operation of the high power gyrotron at 400 kW level, the waveguide switch in the TL was operated to change the direction of RF power. The time duration for the switch operation with inter-subsystem control scheme took 1.5 s in total. The synchronizing of RF power suspend and resume with switch motion has therefore been realized, and RF power direction control during the gyrotron operation was successfully demonstrated.

Although magnifying endoscopy with narrow-band imaging (ME-NBI) can help identify the horizontal margin (HM) of early gastric cancer (EGC), little is known about the factors that can clarify the HM by using ME-NBI. We aimed to characterize the pathological features of lesions in which the HM was identified using ME-NBI. The HMs of 639 differentiated-type EGCs treated with endoscopic submucosal dissection or surgery were analyzed using conventional endoscopy and ME-NBI. The number and width of the intervening parts (IP) and the number, width, and depth of the subepithelial capillaries (SEC) in cancerous and noncancerous areas were measured. In 13 lesions (2.0%), more than 90% of the HM was not recognized with conventional endoscopy, but 11 of these lesions were detectable with ME-NBI (NBI group). The HMs of the other 626 lesions were mostly recognized using conventional endoscopy (WLI/CE group). In the NBI group, the IP width, standard deviation (SD), and number of IPs did not significantly differ between the cancerous and noncancerous areas. However, the SEC number was significantly larger and the depth was shallower in cancerous areas. In the WLI/CE group, the IP width and SD were significantly larger, but the IP number was significantly smaller in cancerous areas. The SEC depth was significantly shallower in cancerous areas. Differences of IP width, SD, and IP number may be factors for identifying HMs with conventional endoscopy. Because NBI can better visualize vessel structures, the increased SEC number and shallow SECs may clarify the HM.

The development of high-power gyrotrons needs matched loads with good performance capable of absorbing and measuring powers as high as 1 MW in the International Thermonuclear Experimental Reactor (ITER) and higher (up to two times) in the future devices, such as the DEMOnstrating fusion power reactor. At Istituto di Fisica del Plasma - Consiglio Nazionale delle Ricerche IFP-CNR (Milan), several spherical loads were developed, all with identical absorbing geometry but different heat removal systems for operations with pulselengths (PLs) from a few milliseconds to continuous wave (CW). A dummy load designed for 2-MW CW 170-GHz operations has been constructed in the frame of the development program of the European gyrotron for ITER. The first prototype hemisphere of this load, joined with an uncoated one, has been successfully tested with long pulses and under vacuum using the gyrotron for ITER of the National Institutes for Quantum and Radiological Science and Technology in Naka. The symmetry of the system is such that the equivalent power (EP) load of the absorbing (coated) hemisphere is doubled when the second one is reflective (uncoated), with an almost unchanged distribution with respect to a fully coated load. The tests demonstrate the capability of the IFP-CNR load to withstand and measure radiation at an EP in an excess of 1.5MW. Experiments involving gyrotron pulses with increasing power and PL have been performed in the load and are reported. The maximum EP load reached in the tests was $\approx 1.8$ MW for 15 s while the longest pulse was 300 s, at $\approx 1$ MW. During the experiments, the temperatures of either the load or the preload were monitored using thermocouples and multiple infrared cameras, while a pressure sensor and a hydrophone have been used for the monitoring of cavitation phenomena and water boiling in the cooling circuits. The results achieved in the tests are described in this paper.

Background Endoscopic resection is recommended for non-ampullary duodenal neuroendocrine tumors (NAD-NETs) ≤10 mm in diameter and confined to the submucosal layer, without lymph node or distant metastasis. However, the efficacy and safety of endoscopic submucosal dissection (ESD) for NAD-NET remains unclear. The aim of this study was to assess the short-term efficacy and safety and the long-term outcomes of ESD for NAD-NET. Methods Eight patients with 8 NAD-NETs who underwent ESD between 2015 and 2018 were included. The indications for ESD were: i) tumor ≤10 mm in diameter; ii) NET G1; iii) confined to the submucosal layer; and iv) without lymph node or distant metastasis. We retrospectively assessed the short- and long-term outcomes and safety. Results The median patient age was 69 (48-76) years. All tumors were located in the duodenal bulb and showed 0-Is morphology. The median size was 6.4 (3-9.3) mm. The rates of en bloc resection, histologically free horizontal and vertical margins, and curative resection were 100%, 88%, and 88%, respectively. Intraoperative and postoperative perforation each occurred in 13% of patients, all of whom were treated conservatively and avoided emergent surgery. Delayed bleeding was not observed. No local, lymph node or distant recurrence was observed during a median follow-up period of 34 (18.5-62.5) months. Conclusions The rates of en bloc and curative resection, and histologically free margins were sufficiently high. Although intraoperative and postoperative perforations occurred, emergency surgery was not needed. The results show that ESD is an efficacious and safe treatment for NAD-NET.

Although colorectal endoscopic submucosal dissection (ESD) has become a standardized procedure worldwide, the difficulty of the procedure is well known. However, there have been no studies assessing the causes of treatment interruption. The present study aimed to evaluate the factors involved in the interruption of colorectal ESD. We retrospectively analyzed 1116 consecutive superficial colorectal neoplasms of 1012 patients who were treated with ESD between August 2008 and September 2018. The clinicopathological characteristics and treatment outcomes were analyzed. Interrupted ESD was reported in 14 lesions (1.3%) of the total study population. Univariate analysis of clinical characteristics indicated that age, 0–I macroscopic-type tumor, and tumor location on the left side colon were risk factors for interruption. Multivariate analysis revealed that 0–I macroscopic-type tumor was the sole preoperative independent risk factor for interruption. Univariate analysis revealed that the presence of muscle-retracting sign (MRS), deep submucosal tumor invasion, and intermediate invasive growth pattern represented the etiology of interruption. Multivariate analysis indicated that MRS can be a sole key sign for the interruption. Additionally, the resectability and curability of 0–I type tumors were significantly inferior to those of predominantly lateral spreading tumors. Observations of 0–I macroscopic-type tumors, MRS, and submucosal deep invasion were significantly more frequent in interrupted cases. Conventional endoscopic images without magnification endoscopy were more associated with interruption than irregular surfaces or Vi pit patterns in cases with 0–I type tumors. ESD of 0–I type tumors is highly disruptive, and undiagnosable submucosal infiltration can reduce the curability.

Stomach cancer rarely develops in patients with familial adenomatous polyposis (FAP), and Helicobacter pylori infection may increase the risk of FAP-related gastric cancer. We describe the case of a 64-year-old woman who developed multiple synchronous early gastric cancers without H. pylori infection. Nine cancer lesions were successfully treated by endoscopic submucosal dissection. An immunohistochemical analysis revealed that the tumors were positive for mucin (MUC)2, MUC6, and CDX2, but negative for MUC5AC, suggesting that the tumors were gastrointestinal mixed type. Periodical endoscopic surveillance is important for the detection of cancers at an early stage.

Background Metatarsus primus elevatus (MPE), a dorsal elevation of the first metatarsal in relation to the lesser metatarsals on lateral-view radiographs, is an indicator of hallux rigidus. The angle between the articular surfaces of the base of the first metatarsal and the anterior part of the medial cuneiform (M1C1A) reflects the sagittal instability of the first tarsometatarsal (TMT) joint. MPE may also indicate instability of the first metatarsal. The purpose of this study was to identify the influence of hallux valgus (HV) and flatfoot (FF) deformities on measurements obtained from first metatarsal-related radiographic images. Methods Standing radiographic images of 134 feet were investigated. In dorsoplantar-view radiographs, HV and intermetatarsal angles were evaluated. The position of the medial sesamoid was classified with a grading system (Hardy score). In lateral-view radiographs, MPE, M1C1A, and Meary's angle were measured. The subjects were divided into 4 groups: the normal group (G1), HV(−)FF(−); the HV group (G2), HV(+)FF(−); the FF group (G3), HV(−)FF(+); and the dual group (G4), HV(+)FF(+). The radiographic parameters were compared among the groups. Results MPE in the HV patients (G2 and G4) was less than that in the non-HV participants (G1 and G3). MPE in G4 was less than that in G3. The odds ratios of the Hardy score were higher in G2, G3 and G4 than in G1. The ratios were higher in the FF patients (G3 and G4) than in the non-FF participants (G1 and G2) and were higher in G4 than in G2. Conclusions FF affects sesamoid dislocation, and the combination of HV and FF further increases sesamoid dislocation. Combined with M1C1A and the Hardy score, MPE may be a useful indicator of three-dimensional instability of the first TMT joint. First TMT joint-related operations may be considered for severe HV treatment in G4 patients.

Introduction Calcaneal pitch angle and Meary’s angle are commonly used to assess longitudinal foot arches on lateral-view radiographs. The aim of this study was to examine and evaluate the radiographic longitudinal foot arch measurement methods with the best intraobserver and interobserver reliabilities for patients with (1) severe cavus deformity and (2) severe flatfoot deformity. Methods Standing radiographic images of 22 feet with severe cavus foot deformity and 49 feet with severe flatfoot deformity were obtained to measure the longitudinal axes of the talus, first metatarsal, calcaneus and plantar surface, which were defined using six, five, four and three different methods, respectively, selected from previous reports. Intraobserver and interobserver correlation coefficients were calculated. Results The results are generally consistent with those of Part 1. The best intraobserver and interobserver correlation coefficients for the tarsal axes were obtained using methods involving a line bisecting the angle formed by the lines tangential to the superior and inferior margins of the talus, a line connecting the centre of the first metatarsal head and the midpoint of the visualized base of the first metatarsal, and a line drawn tangential to the inferior surface of the calcaneus. For the plantar axis, a method that used the horizontal plane (as a reference axis) was regarded as the best approach. Conclusions The aforementioned methods were considered to be optimal for the radiographic assessment of longitudinal foot arches in patients with severe cavus or flatfoot deformity. This study may contribute to the more accurate assessment of any foot deformity.

Mechanical and quasi-optical design of an electron cyclotron heating/current drive launcher for JT-60SA is in progress. A full-scale mock-up of the steering structure, which enables linear and rotation motions of the first mirror of the launcher, has been fabricated for cyclic test of the bellows part. Moreover, an improved design enables easy replacement of the bellows for rotation for maintenance. Quasi-optical characteristics of the antenna mirrors have been studied to evaluate its transmission efficiency and beam focusing property. In calculation, it was found that the antenna is applicable to two frequency operation at 110 GHz and 138 GHz. It was quantitatively shown that the transmission efficiency of ∼99% (not including Ohmic loss) is obtained even with the higher order mode (LP11even) fraction of 10% by optimizations of the shape of the first mirror. These results contribute to optimization/finalization of the launcher design toward fabrication of the launcher for JT-60SA.

The ITER electron cyclotron system is designed to inject a 20 MW RF beam by using twenty-four 170 GHz/1 MW gyrotrons. JAEA is currently developing a gyrotron having a high-order mode (TE31,11) to reduce the heat load in the cavity resonator and achieve an output power greater than 1 MW. The measured radiation profile at the front of the diamond window agreed with the results of the calculation. In order to suppress RF loss in the equatorial and upper port launchers, a high-quality HE11 mode is required at the exit of the matching optics unit (MOU). An HE11 mode purity of 96% was achieved by finely adjusting the two mirrors in the MOU. During the oscillation start-up phase, mode competition with counter-rotating TE29,12 mode was observed on the higher magnetic field side which caused arcing and pressure increase in the gyrotron. To avoid the counter-rotating TE29,12 mode from being excited, a start-up scenario that controls the voltage between the anode and cathode electrodes at the initial phase of operation was introduced, which was able to achieve a stable start-up of TE31,11 mode. A 1.2 MW output power having a total electric efficiency of 43% was obtained in high-power experiments. In steady-state operation, a 1000 s oscillation length and output power of 0.51 MW was achieved.

The design modification of the ITER equatorial electron cyclotron (EC) launcher to enhance off-axis current drive performance, changing the steering capability of injection beams from toroidal to poloidal, is described. The modification requirement impacts the design of all 3 millimeter wave beam paths transmitted through the port plug and blanket shield modules (BSMs) installed in front. The optimized configuration of the mm wave design consisting of both steering and fixed mirrors, beam ducts between the waveguide outlet and BSM openings are successfully developed. Assuming a 100% pure HE 11 mode propagated at the waveguide output, a 99% transmission efficiency from the waveguide outlet to the BSM output is obtained. This modification ensures that mm wave beams from both middle and bottom beam row pass through the same BSM opening and will lead to the increase of neutron shielding potential. The configurations of BSMs are also modified maintaining the structural design concept of each module. The preliminary result of electromagnetic analysis shows that induced force and momentum torque on the modified BSMs are below the mechanical criteria of the BSMs’ support structure.

Background. Vonoprazan affords more clinical benefits than proton pump inhibitors (PPIs) during the healing of gastroduodenal ulcers. However, it remains controversial whether vonoprazan is more effective than PPIs when used to heal artificial ulcers arising after endoscopic submucosal dissection (ESD). Aim. This study investigated the effects of vonoprazan compared with esomeprazole on the healing of post-ESD artificial ulcers. Methods. Sixty patients who underwent gastric ESD between May 2015 and May 2017 were randomized to treatment with vonoprazan (V group) or esomeprazole (E group) for 8 weeks. Upper endoscopy was performed at 4 and 8 weeks after ESD, and drug effects were estimated based on the ulcer healing rates and shrinkage rates. Results. Fifty-three patients were analyzed. The respective 4- and 8-week ulcer healing rates did not differ significantly between V and E groups (8.0 versus 11.5%, P=0.669; 88.9 versus 84.6%, P=0.420). Similarly, the respective 4- and 8-week ulcer shrinkage rates did not differ significantly between V and E groups (96.8 versus 97.5%, P=0.656; 100 versus 100%, P=0.257). Conclusion. The healing of artificial ulcers after ESD did not differ using vonoprazan or esomeprazole. Both vonoprazan and esomeprazole were effective when used to promote artificial ulcer healing after ESD.

Background and study aims Endoscopic submucosal dissection (ESD) is used to treat superficial colorectal tumors. Previous studies have reported the efficacy of ESD for treating residual or local recurrent colorectal tumors. This study sought to evaluate the efficacy of ESD in treating these lesions and to assess factors that prevent successful ESD. Methods This retrospective study assessed 25 cases of residual or local recurrent lesions that were previously treated using EMR (18 lesions), TEM (5 lesions), ESD (1 lesion) or surgery (1 lesion), and 459 primary lesions treated using ESD between April 2008 and September 2015. Clinicopathological characteristics, treatment outcome and adverse events were compared between groups with or without scar tissue. Factors related to perforation and a prolonged treatment time, which indicate the likelihood of technical difficulties, were identified using multiple logistic regression analysis. Results In residual or local recurrent lesions groups, patients experienced more perforations (32 % vs 4 %, P Conclusions ESD for residual or local recurrent colorectal tumors is a technically challenging, but effective and minimally invasive treatment. When performed carefully with sufficient proficiency, it is a useful treatment option.

Recent progress of QST high power high frequency gyrotrons is reported. Main motivation of the high power gyrotron is the application to the plasma heating and current drive and control of the magnetic confinement fusion devices. Using a multi-frequency operation, 1 MW Gaussian beam output was obtained at four frequencies; 203 GHz (TE37,13), 170 GHz (TE31,11), 137 GHz (TE25,9), 104 GHz (TE19,7). In particular, the achievement of 203 GHz 1 MW output at 50 % will give a strong impact on the DEMO (Demonstration power plant) design. In parallel, a high frequency oscillation up to 300 GHz was studied using a short pulse gyrotron under collaboration with University of Tsukuba. In this gyrotron, 300 GHz/ 0.6 MW (TE 31 , 18 ), 240 GHz/ 0.35 MW (TE 28 , 14 ) oscillations were demonstrated.

Background and Aims Several reports have described major adverse events after endoscopic submucosal dissection (ESD), such as perforation or bleeding. However, few studies have discussed the occurrence of post-ESD electrocoagulation syndrome (PEECS) after colorectal ESD. In addition, the occurrence of fever without abdominal pain in patients requires postoperative management similar to that required for PEECS. Therefore, we have defined post-ESD inflammatory syndrome (PEIS) composed of both PEECS and fever without abdominal pain. This study aimed to evaluate the correlation between the findings of multi-detector computed tomography (MDCT) imaging and PEIS in patients. Methods Between January 2015 and October 2015, we performed colorectal ESD in 100 patients; after this, all patients underwent abdominal examinations by MDCT scans. Nine patients who experienced intraoperative perforations or penetrations were excluded; 91 patients were enrolled in our prospective study. MDCT findings in patients were classified according to the amount of extraluminal gas. The patients were divided into 2 groups based on the presence or absence of extraluminal gas and were assessed for co-occurring PEIS. Results Among the 91 patients, extraluminal gas was observed in 31 (34%); of these, PEIS occurred in 14 (15%) patients. Patients with extraluminal gas had increased incidence of PEIS compared with patients without extraluminal gas (29% vs 8%, P = .014). Conclusions Extraluminal gas was detected by MDCT in many cases and significantly correlated with the occurrence of PEIS, even in cases without obvious intraoperative perforation or penetration. MDCT findings after ESD may be useful for predicting PEIS and appropriate perioperative management.

This study presents a new method to identify parameters representing cutting process and transfer function of flexible mechanical structures mounted on a traveling stage by utilizing only internal information of computerized numerical control (CNC) system. Disturbance force input to CNC is estimated by disturbance observer and cutting force is estimated based on cutting force model. Analyzing influence of the estimated cutting force on the disturbance force, parameters used in the assumed models of cutting process and structural dynamics are identified in quasi-real-time. Least square method (LSM) is utilized for the parameter identification. Face turning experiment using an ultra-precision machine tool was conducted to verify feasibility of the proposed method. Experimental results clarified that the cutting force coefficient and the modal parameters representing the dynamic characteristics of the force transfer function can be identified accurately by the proposed method.

In this paper we present results that demonstrate the utility of a continuously frequency-tunable 0.4 THz-gyrotron in a dynamic nuclear polarization (DNP)-enhanced solid-state NMR (SSNMR) spectroscopy at one of the highest magnetic fields, B0 = 14.1 T (600 MHz for 1H Larmor frequency). Our gyrotron called FU CW VI generates sub-mm wave at a frequency near 0.4 THz with an output power of 4–25 W and a tunability over a range of more than 1 GHz by sweeping the magnetic field at the gyrotron cavity. We observed overall down shifting of the central frequency by up to ~1 GHz at high radiation duty factors and beam current, presumably due to the cavity thermal expansion by a heating, but the tunable range was not significantly changed. The frequency tunability facilitated the optimization of the DNP resonance condition without time-consuming field-sweep of the high-resolution NMR magnet, and enabled us to observe substantial enhancement of the SSNMR signal (eDNP = 12 at 90 K).

The measurement of the ion velocity distribution is especially important in reactor relevant plasmas. The collective Thomson scattering (CTS) is one of the most promising methods for evaluating the ion velocity distribution function. In spite of its potential, this method had long been suffered from the absence of adequate power sources. Recent development in the higher power, and higher frequency range of the gyrotron and the transmission technique enabled to realize the measurement of not only the bulk but also high energy component of the ion velocity distribution function. One of the newly installed 77 GHz gyrotrons in LHD that can generate more than 1 MW over 5 s and is connected to one of the Gaussian mirror beam launching antenna sets is used as a probing beam for CTS. A heterodyne receiver system of a fundamental mixer with fixed frequency local oscillator was installed on the upstream of the transmission line. The probe beam is 100% power modulated at 50 Hz to separate the scattering component from background ECE. Signals that can be attributed to the CTS were obtained and the analysis method of these data are developed (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A high frequency gyrotron with a 15 T superconducting magnet named Gyrotron FU CW VI has achieved continuous frequency tuning through the relatively wide range of 1.5 GHz near 400 GHz. The operation is at the fundamental cyclotron resonance of the TE06 cavity mode with many higher order axial modes. The output power measured at the end of the circular waveguide system ranges from 10 to 50 watts at the low acceleration voltage of 12 kV for beam electrons. The beam current is also low. It is around 250 mA. This gyrotron is designed as a demountable radiation source for the 600 MHz DNP-NMR spectroscopy. The design and operation results of the gyrotron FU CW VI are presented.

Investigation of experimental configuration for the electron Bernstein wave (EBW) heating by using the existing electron cyclotron heating (ECH) antennas on LHD was performed. By using an antenna installed in the lower port, direct oblique launching of the extraordinary (X-) mode from the high magnetic field side (HFS) is available. Since the parallel component of the refractive index (N||) varies during propagation because of the inhomogeneity of the magnetic field, N|| can be zero when the launched X-mode crosses the fundamental electron cyclotron resonance (ECR) layer even N|| is noonzero initially. In such a condition, if the electron density is above a certain level the obliquely launched X-mode can pass the fundamental ECR layer without being damped out and can be mode-converted to EBW that is absorbed at the Doppler shifted ECR layer. By using an antenna installed in the horizontal port, oblique launching from the lower magnetic field side (LFS) toward the over-dense plasma is available. Excitation of EBW via the mode conversion process of ordinary mode(O)-extraordinary mode(X)-electron Bernstein wave (B) is expected with the O-mode launching toward an appropriate direction. The O-X-B mode conversion rate and the region of power deposition were surveyed by varying the magnetic field strength and the launching direction. The results of the survey suggest that efficient heating in the core region is difficult by using the existing antenna. Rearrangement of the final mirror of the launching antenna may be needed.

A fatigue testing machine for thin sheet specimens was developed to clarify the crystallographic orientation dependence on fatigue fracture behavior in magnesium single crystals. The size of the thin sheet specimen was 3mm in width and 0.3mm in thickness. One end of the thin sheet specimen was fixed at a voice coil of a loudspeaker and the other end was set free. A bending mode resonance occurs in the specimen due to forced vibration at the fixed end. To estimate stress amplitude, the displacement of the free end of the specimen was measured with a laser displacement meter. The stress amplitude was evaluated as the bending stress in the single cantilever. Fatigue tests were carried out with stress ratio R = –1 at room temperature in laboratory air and the frequency of the cyclic stress was 981Hz. In A-specimen whose surface plane and loading direction were (0001) and [1120], a fatigue crack propagated along [1100] at higher stress level while a crack propagated along [1210] at lower stress level. In B-specimen whose surface and loading direction were (1120) and [1100], a crack propagated partially along {1012} twin interface. As a result, fatigue life of the B-specimen was longer than that of the A-specimen. The fatigue limits of the A- and B-specimens were nearly the same, and it was estimated as 45MPa at 106∼108 cycles. The fatigue testing machine developed in this study showed the crystallographic orientation dependence on fatigue fracture behavior in magnesium single crystals.

A short pulse high order mode gyrotron for 300 GHz oscillation was tested. The designed oscillation mode is TE 32,18 and the gyrotron is operated with a 13T superconducting magnet. The output RF power and its frequency was measured. In the preliminary experiment, the 520 kW power was obtained at 299.85 GHz which corresponds to designed oscillation mode.

High-power, long-pulse operations of a gyrotron for JT-60SA (Super-Advanced) have been carried out at 110 GHz (1 MW/100 s) and 138 GHz (1 MW/100 s). These results fully satisfied the requirements of the electron cyclotron heating and current drive (ECH/CD) system in JT-60SA. It was experimentally shown that the higher power operation at each frequency is expected to be acceptable for this gyrotron from the viewpoint of heat load at the cavity resonator, collector, and stray radiation absorbers. An oscillation of 1 MW for 1 s at 82 GHz has been demonstrated as an additional frequency of the same gyrotron. Experiments toward 1.5 MW or higher at 110 GHz and 138GHz are ongoing.

For the Electron cyclotron resonance heating and current drive (ECH&CD) system on fusion DEMO reactor, the high power mm-wave of 200 GHz ∼300 GHz is expected. To increase the gyrotron frequency, extremely high-order oscillation mode should be adopted to suppress the Ohmic loss on the resonator wall less than ∼20 MW/m2. Here, we designed and fabricated a 300 GHz gyrotron of TE 32,18 mode oscillation and started a short pulse experiment to investigate the oscillation characteristics of the high order mode at ∼300 GHz. As a preliminary result, we demonstrated the power generation of ∼0.5 MW at ∼300 GHz oscillation at the oscillation mode of TE 32,18 , and other modes.

A mode conversion miter-bend with angle controllable mirror was developed. By changing mirror angle, RF beam angle in the miter bend is controlled and transmission mode contents (LP01 and LP11 modes) are controlled. The miter bend was tested at 170 GHz mW-class low power RF system. The dependence of miter bend mirror angle and ratio of LP01 and LP11 modes was acquired. The concept of mode conversion system was validated.

In JAEA, development of high power gyrotron is underway. One activity is a 1 MW/170 GHz gyrotron development for ITER application and another is a dual frequency (138GHz/110GHz) gyrotron for JT-60U. The advanced mode TE 31,11 was adopted for high power generation and multi-frequency operation. Up to now, 1.24 MW/2sec was obtained with DC input of 50 kV×55A, which is available by ITER power supply. In the multi-frequency operation, 1MW oscillation was obtained at three frequencies: 170 GHz, 137 GHz and 104 GHz. And, high efficiency long distance power transmission from the gyrotron window to the end of the 40 m transmission line were demonstrated: 91 %, 89 % and 84 %, respectively. On the other hand, in the dual frequency gyrotron development, the power output of 1 MW/100 s, which is the target of the JT-60SA, were achieved for both frequencies (138 GHz/110 GHz).

Recently carbon-11 acetate (AC) positron emission tomography (PET) has been reported to be of clinical value for the diagnosis of cancer that is negative on fluorine-18 fluorodeoxyglucoce (FDG) PET. We investigated the uptake of AC in lung cancer to determine whether this tracer is of potential value for tumour detection and characterisation, and to compare AC PET imaging with FDG PET and technetium-99m sestamibi (MIBI) single-photon emission tomography (SPET). Twenty-three patients with 25 lung cancers underwent AC and FDG PET. Twenty of 23 patients were also investigated with MIBI SPET. Dynamic images were acquired for 26 min after the injection of 555 MBq of AC. Standardised uptake values (SUVs) and/or tumour to non-tumour activity ratios (T/N) for each tumour were investigated at 10–20 min after AC administration, 40–60 min after administration of 185 MBq FDG and 15–45 min after administration of 555 MBq MIBI. Twenty lung cancers were resected surgically, and the degree of tracer uptake in the primary lesion was correlated with histopathological features (cell dedifferentiation and aggressiveness) and prognosis. Rapid uptake of AC followed by extremely slow clearance was observed. For the purpose of tumour identification, AC PET was inferior to FDG PET in 8 of 25 (32%) lung cancers, and the T/N of AC was lower than that of FDG. However, AC PET was superior to FDG PET in the identification of a slow-growing tumour (bronchiolo-alveolar carcinoma). There was a positive correlation between AC uptake (T/N) and MIBI uptake (T/N) (r=0.799, P

18F-fluorodeoxyglucose (FDG) PET imaging provides physiologic and metabolic information that characterizes lesions that are indeterminate by CT. FDG PET imaging is sensitive to the detection of lung cancer in patients who have indeterminate lesions on CT, whereas low grade malignancy such as bronchioloalveolar carcinoma and carcinoid may be negative on FDG PET. The specificity of PET imaging is less than its sensitivity because some inflammatory processes, such as active granulomatous infections, avidly accumulate FDG. This possibility should be kept in mind in the analysis of PET studies of glucose metabolism aimed at differentiating malignant from benign solitary pulmonary nodules. FDG uptake is considered to be a good marker of cell differentiation, proliferative potential, aggressiveness, and the grade of malignancy in patients with lung cancer. FDG PET accurately stages the distribution of lung cancer. Several studies have documented the increased accuracy of PET compared with CT in the evaluation of the hilar and mediastinal lymphnode status in patients with lung cancer. Whole-body PET studies detect metastatic disease that is unsuspected by conventional imaging. Management changes have been reported in up to 41% of patients on the basis of the results of whole-body studies. Whole-body FDG PET is also useful for the detection of recurrence. Several studies have indicated that the degree of FDG uptake in primary lung cancer can be used as an independent prognostic factor. Thus, whole-body FDG PET is clinically very useful in the management of lung cancer.

The development of high power gyrotrons needs matched loads with good performance capable of absorbing and measuring powers as high as 1 MW in ITER and higher (up to two times) in future devices like DEMO. At IFP-CNR (Milano), several spherical loads were developed with identical absorbing geometry but different heat removal systems for operation with pulse lengths from a few ms to CW. A dummy load designed for 170 GHz/2 MW has been constructed in the frame of the development programme of European gyrotron for ITER. The first prototype hemisphere of this load, joined with an uncoated one, has been successfully tested with long pulses and under vacuum using the JAEA gyrotron for ITER in Naka. The symmetry of the system is such that the equivalent power load of the absorbing (coated) hemisphere is doubled when the second one is reflective (uncoated), with almost unchanged distribution with respect to a fully coated load. The tests demonstrate the capability of the IFP-CNR load to withstand and measure radiation at an equivalent power in excess of 1.5 MW. Gyrotron pulses with increasing power and pulse length have been performed in the load and are reported. The maximum equivalent power load reached in the tests was ∼ 1.8 MW for 15 s while the longest pulse was 300 s, at ∼ 1 MW. During the experiments, the temperatures of either the load or the preload were monitored using thermocouples and multiple infrared cameras. The results of the tests are described in the paper.