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Esophagogastroduodenoscopy (EGD) is an aerosol-generating procedure. A major challenge in the COVID-19 era is how to prevent the spread of aerosols and droplets in endoscopic units. We evaluated the effectiveness of an extraoral suction device in preventing indoor aerosol diffusion and droplet exposure for examiners. The study involved 61 patients who underwent EGD at our institution from 1 February to 31 March 2022. To determine whether aerosol spread increases before or after EGD examination with an extraoral suction device located in front of the patient’s mouth, aerosols of 0.3, 0.5, 1, 3, 5, and 10 μm were measured with a handheld particle counter. The degree of contamination of the plastic gowns on the examiners was assessed using the rapid adenosine triphosphate test. The extraoral suction device significantly reduced the diffusion of large particles (3, 5, and 10 μm) after finishing the EGD examination. However, the diffusion of small particles (0.3 and 0.5 μm) was significantly increased. This extraoral suction device was effective in reducing large particle diffusion during EGD examination but was limited for minimizing small particle diffusion or droplet exposure to the examiner.

Background The recently developed endoscopic full-thickness resection technique requires reliable closure. The main closure methods are the purse-string suture (PSS) technique and over-the-scope clip (OTSC) technique; however, basic data on the closure strength of each technique are lacking. This study was performed to compare the closure strengths of these two methods in an ex vivo porcine model. Methods In the traction test, a virtual 5-cm full-thickness closure line was closed by the following six methods three times each: conventional hemoclips, mucosal PSS, seromuscular PSS, mucosal OTSC, seromuscular OTSC, and surgical suture. The primary endpoint was the tension at the starting point of dehiscence, measured in Newtons (N) by an automatic traction machine. In the leak test, a 15-mm gastric full-thickness defect was closed by PSS or OTSC six times each, and the closed stomach was then pressurized in a water container. The primary endpoint was the leak pressure when air bubbles appeared. The secondary endpoints were the procedure time and presence of complete inverted closure. Results The mean tension was 2.16, 3.68, 5.15, 18.30, 19.30, and 62.40 N for conventional hemoclips, mucosal PSS, seromuscular PSS, mucosal OTSC, seromuscular OTSC, and surgical suture, respectively. Complete inverted closure was observed for seromuscular PSS, seromuscular OTSC, and surgical suture. The mean leak pressure was 13.7 and 24.8 mmHg in the PSS and OTSC group, respectively (P Conclusion The OTSC, which allows complete inverted closure, showed greater closure strength than PSS. Considering the size limitation suitable for single OTSC, a therapeutic strategy for closing the larger size is further warranted.

The management of postoperative bleeding, after gastric endoscopic submucosal dissection (ESD), has become particularly important because of the recent increase in antithrombotic use. Endoscopic shielding with polyglycolic acid (PGA) sheets has been shown to be effective. However, shrinkage and early displacement of the sheet remain challenges. This study aimed to determine the efficacy and safety of our developed method, named wafer paper and ring-mounted PGA sheet (WaRP).Twenty-four patients with antithrombotic uptake who underwent the WaRP method following gastric ESD were retrospectively examined. This involved the delivery of a PGA sheet wrapped in wafer paper with ring-thread, and its fixation on the gastric floor using hemoclips. The primary outcome was the technical success rate of the WaRP, and several secondary outcomes were evaluated.The technical success rate of WaRP was 100%. The procedure lasted a mean of 10.5 min (SD 6.7 min). The prevalence of complete retention at follow-up endoscopy was 83.3% (20/24). There were no WaRP-associated complications, but post-ESD hemorrhage occurred in two patients undergoing hemodialysis (8.3%).The WaRP method is a simple and reliable means of PGA sheet delivery and placement that reduces the incidence of post-ESD hemorrhage.

Background and study aims Exposed endoscopic full-thickness resection (EFTR) enables the operator to obtain a sufficient surgical margin. However, insufflation leakage and secure endoscopic full-thickness closure (EFTC) remain problematic. This study aimed to evaluate the safety and feasibility of a new exposed EFTR. Patients and methods Exposed EFTR was performed for 2-cm virtual lesions in different locations of the upper stomach in four dogs. EFTR mainly involved half-circumferential EFTR of the endpoint and clip-line traction. Pulley traction was applied with the forward approach for the greater curvature. EFTC involved endoscopic ligation with O-ring closure to diminish insufflation leakage, followed by over-the-scope clip closure. Results Complete resection and technical success were achieved in all four cases. One case of intraoperative bleeding was endoscopically managed. No postoperative complications occurred in any cases. The median maximum resected size was 27.5 mm. The median procedure time of the total operation, EFTR, and EFTC was 76, 37, and 35.5 minutes, respectively. The 1-month survival rate was 100 %. Conclusions This therapeutic strategy may lead to the establishment of exposed EFTR.

Background We examined the efficacy of a novel endoscopic ligation technique with O-ring closure (E-LOC) to prevent bleeding after gastric endoscopic submucosal dissection (ESD) under antithrombotic therapy. Methods This single-center prospective study involved consecutive patients who were taking antithrombotic agents and underwent gastric ESD. E-LOC was performed by anchoring the nylon loop with hemoclips on both defect edges and/or the exposed muscle layer, and using O-ring band ligation around these deployed clips. The primary outcome was post-ESD bleeding rate. Secondary outcomes were complete closure rate, procedure time, sustained closure rate, and complications. Results 48 patients were finally analyzed. The post-ESD bleeding rate was 0 %, the complete closure rate was 97.9 %, and the mean closure time was 29.9 minutes. The sustained closure rate was 95.8 % at postoperative day 2–3 and 33.3 % at postoperative day 10–11. No complications occurred. Conclusion E-LOC may be an effective option for closing mucosal defects after gastric ESD under antithrombotic therapy. However, the preventive effect on post-ESD bleeding should be further investigated in high risk groups.

Esophagogastroduodenoscopy (EGD) has a high risk of virus transmission during the current coronavirus disease 2019 era, and preventive measures are under investigation. We investigated the effectiveness of a newly developed patient-covering negative-pressure box system (Endo barrier®) (EB) for EGD. Eighty consecutive unsedated patients who underwent screening EGD with EB use were prospectively enrolled. To examine the aerosol ratio before, during, and after EGD, 0.3- and 0.5-μm aerosols were measured every 60 s using an optical counter. Moreover, the degree of contamination of the examiners’ goggles and vinyl gowns was assessed before and after EGD using a rapid adenosine triphosphate (ATP) test for simulated droplets. Data were available in 73 patients and showed that 0.3- and 0.5-μm particles did not increase in 95.8% (70/73) and 94.5% (69/73) of patients during EGD under EB. There were no significant differences in the total 0.3- or 0.5-μm particle counts before versus after EGD. The difference in the ATP levels before and after EGD was −0.6 ± 16.6 relative light units (RLU) on goggles and 1.59 ± 19.9 RLU on gowns (both within the cutoff value). EB use during EGD may provide a certain preventive effect against aerosols and droplets, decreasing examiners’ exposure to viruses.

Pooled gastric residues involving blood clots and food interrupt appropriate endoscopic intervention, leading to poor outcomes in endoscopic hemostasis and lifesaving. However, procedures and devices that enable the effective removal of gastrointestinal residues remain unsatisfactory. This study aimed to evaluate the efficacy and safety of our developed suction method in ex vivo and in vivo studies. We created a hand-made device with a large suction diameter, consisting of a balloon overtube and an ultrathin endoscope for navigation. In the ex vivo study, we compared the success rate and the suctioning time for four types of simulated residue between a standard endoscope and our device. Our device had s significantly higher suction ability and a shorter procedure time than the standard endoscope. The subsequent in vivo animal study involved five beagle dogs that were administered with food jelly to mimic gastric residue. Suction was performed twice for five dogs (ten attempts). The outcome measure was the successful procedure rate, secondary outcomes were procedure-associated complications and procedure time. The procedure was successful in all attempts, without any complications. The mean procedure time was 5 min. This novel method enabled the efficient and safe removal of gastric residue, and our findings will likely lead to the development of the instrument.

The Over-The-Scope Clip (OTSC) can effectively treat refractory gastrointestinal diseases. However, most reports have focused on short-term effectiveness. We examined clinical outcomes of the deployed clips and long-term characteristics.Of 47 patients with OTSC treatment, 35 with follow-up periods of ≥3 months were retrospectively examined. The indications were 11 bleedings, 17 perforations, and seven fistulas. The observation period was defined as medium-term (3 to12 months) or long-term (≥12 months). The primary outcome was the clinical success rate without disease recurrence. The secondary outcomes were the complication rate, survival duration, and clip retention rate.The medium- and long-term clinical success rates were 100% during the observation period (median, 44 months; range, 3-78 months). The complication rate was 2.9% (Regardless of clip detachment, the OTSC can be effective in long-term.

The Over-the-scope clip (OTSC) has been recently introduced for multiple purposes, including refractory bleeding, perforation, fistula, and anastomotic dehiscence of the gastrointestinal tract. However, no easy access techniques for delivering OTSCs to distant sites have been described. Therefore, we have developed a simple and safe guidewire-assisted OTSC delivery (GOD) method for use on the distal intestine. This study aimed to investigate the technical feasibility and safety of the method.Between June 2018 and April 2019, all eight patients who underwent the GOD method were retrospectively examined. The primary outcome was the successful rate of OTSC delivery to the lesion without complications. The secondary outcomes were GOD procedure time, total procedure time, technical and clinical OTSC success rates, and GOD- and OTSC-associated complications.The rate of successful OTSC delivery was 100%. The median procedure time of GOD was 21 min (range 8-29). The median total procedure time was 38.5 min (range 26-41). The technical and clinical success rates of OTSC were 100% and 75% (6/8), respectively. No GOD- or OTSC-associated complications occurred.The GOD method is a feasible and safe technique for delivering OTSC toward the small and proximal large intestine.

Background Endoscopic submucosal tunnel dissection (ESTD) has recently been an effective procedure for resecting large early esophageal neoplasm. However, excessive dissection beyond the distal limit may occur because the prepared distal end often cannot be distinguished through the tunnel. This study aimed to assess the efficacy and safety of a novel crystal violet navigation (CVN) for identifying the distal end. Material and methods In the observational case series study, all 22 patients who underwent esophageal ESTD using the CVN were included. When setting the distal end, the distal incision line was dyed purple using a crystal violet solution. The rates of purple color identified via the tunnel, successful tunnel penetration without extra dissection, en bloc and curative resection, procedure time for ESTD and CVN, and procedure-associated complications were evaluated. Results The rates of purple color and successful tunnel penetration were both 100%. En bloc and curative resection were 100%, and 86%, respectively. The mean total procedure time was 103.9 ± 46.2 (mean ± SD) minutes, while the mean time for the CVN was 14.1 ± 3.44 s. No complications were observed. Conclusions The simple CVN method can be a navigation tool for identifying the distal end during the ESTD procedure.

In all endoscopic ultrasound (EUS) examinations performed at our hospital, the heart, vasculature, and mediastinal lymph nodes from the esophagus are observed after checking for gastrointestinal pathologies. Since the introduction of EUS using a convex linear-array echoendoscope at our hospital in April 2015, EUS examinations have been performed in 371 cases for examining pancreaticobiliary diseases, submucosal tumors, and other pathologies during the 3-year period, till March 2018. We diagnosed 2 patients with asymptomatic cardiovascular disease while observing the mediastinum during EUS examination to examine identified pancreaticobiliary disease. No subjective symptoms associated with cardiovascular disease were observed and the respective conditions had not been identified previously in either case. One case involved a left atrial myxoma while the other involved a saccular aortic aneurysm in the thoracic aorta. A left atrial tumor resection and aortic replacement surgery were performed in each case. Their postoperative courses have been favorable. As cardiovascular diseases are often life-threatening, as in the present 2 cases, observational screening of the cardiovascular system from the esophagus should also be performed during EUS examinations just as the pharyngeal region is examined during upper gastrointestinal endoscopy.

We attempted to detect a typical driver's surprised state based on blood pressure using a driving simulator. The results show that the driver's systolic blood pressure after a child and a bicycle rushed out on the road is higher than that before child and bicycle rushed out, and these two data are statistically significant. This means that the systolic blood pressure became high when the bicycle rushed out, thus suggesting that the feeling of “traffic near-miss” (surprised) can be detected via blood pressure. In addition that, systolic blood pressure is more adequate index to detect driver's surprised state than LF/HF, which is generally used to detect or estimate driver's surprised state.

Traffic accidents caused by fatigue and/or overwork driving on driving for ling-time never ceased and we are attempting to evaluate and estimate fatigue. 3 participants drove on a highway course consisted of a slow lane and a passing lane for about an hour and were measured their R-R interval. Their fatigue level was analyzed based on LF/HF, which is calculated by Fast-Fourier-Transformed (FFT) R-R interval. From experiment and data analysis, 2 participants were seemed to get to be fatigue state judging from increasing of LF/HF.

To realize driving support systems friendly to drivers, it is important to detect the driver states (consciousness degradation, inattention etc.). This paper describes the development of a technique to detect the gaze direction of a driver during driving by the time-varying image processing. In this method, the facial direction and the gaze direction can be detected separately. The verification experiments proved that the developed method is applicable for the detection of inattention.

The schlieren photographs of in-cylinder processes in a spark-ignited premixed charge gasoline engine were observed via a transparent collimating cylinder and were presented in comparison with a pressure analysis. The schlieren photographs of the spark, the initial flame and the unburned gas ejection from the piston crevice, which is unable to be observed by direct photography, were clearly taken. It shows that the small difference in the initial combustion process among cycles is intensified by the movement of the piston during the expansion stroke. Finally, this difference appears as the cycle by cycle variation in the pressure and the rate of heat release. The observed flame size increased faster and was larger than the burned gas estimated from the pressure. The difference between them is large enough and can not be explained without considering the mixing of burned and unburned gases inside the flame front.

The number of deaths from traffic accidents in Japan has been reduced for this 13 consecutive years. One of the reasons is that the collision prevention safety devices for vehicle are developed and equipped many vehicles and it is needed to detect the state of drivers in order to reduce the number of traffic accident more. We are trying to develop this system based on blood pressure and show the efficacy of estimation driver’s state based on blood pressure. As a feasibility study, we attempted to estimate driver’s state that transits from calm to surprising, which is typical driver’s state, based on blood pressure using driving simulator. As a result of experiment, the systolic blood pressure after bicycle rushed out is higher than that before bicycle rushed out and these two data are statistically significant. This means that the systolic blood pressure get to be high when bicycle rushed out thus the feeling of “traffic near-miss” (surprising) can be detected from blood pressure.

Novel methods to recognize license plates robustly are presented. A sensing system with a wide dynamic range has been developed to acquire fine images of vehicles under varied illumination conditions. The developed sensing system can expand the dynamic range of the image by combining a pair of images taken under different exposure conditions. In order to avert blurring of images against fast passing vehicles, a prism beam splitter installed a multilayered filter, and two charge-coupled devices are utilized to capture those images simultaneously. Furthermore, to extend the flexibility of camera placement, a recognition algorithm that can be applied to inclined plates has been developed. The performance of recognizing registration numbers on license plates has been investigated on real images of about 1000 vehicles captured under various illumination conditions. Recognition rates of over 99% (conventional plates) and over 97% (highly inclined plates) showed that the developed system is quite effective for license-plate recognition.

In this paper a gate access control system using a microwave identification (ID) tag system is presented. A read/write microwave ID tag system powered by a battery has been developed. The main features of this ID tag system as a stand alone tag are high data transmission rate (2.4kbytes/sec) and low power consumption. A prototype gate access control system using this ID tag system at automobile assembly plants has been developed. For this system, 120 byte data transmission has been typically attained at vehicle speed of 50km/h. This system was applied to the traffic control of delivery trucks in automobile assembly plants. The system has been successfully stood various tests for 1 year. The data retransmission of the system was 0.25% of 15, 000 access but there was no transmission error, thus the prototype system is effective for gate access control in plants.

This paper presents novel methods of recognizing vehicle license plates robustly. To acquire fine images of quickly passing vehicles under a wide range of illumination conditions, we developed a sensing system having superb characteristics. We expanded the dynamic range and eliminated the blurring of images of fast moving vehicles by synthesizing a pair of images with different intensities. Furthermore, to extend the flexibility of the positioning of the TV camera, we propose a recognition algorithm which can be applied to much inclined plates. The performance of the integrated system was investigated on real images of highly inclined plates captured under various illumination conditions. The recognition rates of over 99% (conventional plates) and about 97% (highly inclined plates) show that the developed system is effective for license plate recognition.

This paper presents novel methods of recognizing license plates of passing vehicles outdoors. In particular, the proposed method is very robust for inclined plates caused by changes of camera placement. To acquire fine images of quickly passing vehicles under a wide range of illumination conditions, we developed a sensing system with superb characteristics. We expanded the dynamic range and eliminated the blurring of images of fast moving vehicles by synthesizing a pair of synchronized images with different intensities. Furthermore, to extend the flexibility of the positioning of the TV camera, we propose a recognition algorithm that can be applied to inclined plates. The performance of the integrated system was investigated on real images of vehicles captured under various illumination conditions. The recognition rates of over 99% (conventional plates) and over 97% (highly inclined plates) shows that the developed system is effective for license plate recognition.

A single cylinder visualization engine with the TCC (transparent collimating cylinder) was applied to the study of a direct-injection gasoline engine. Fuel sprays, mixture forma-tion and combustion process in the cylinder were observed using the schlieren method. The schlieren images were analyzed by image analysis technique. The shapes of the fuel spray are drastically changed with the injection timing ; namely oval shaped when in-jecting during the suction stroke, conical shaped when injecting near BDC, and bell shaped when injecting during the compression stroke. The fuel/air mixture formations also change with the injection timing. When the injection timing is late, the mixing of fuel and air is also late and the luminous region in the schlieren image of the mixture be-comes clear. In the case of the injection timing of 60 deg. before TDC, the injected fuel spray impinges on the top of the piston and the fuel/air mixture exists around the top of the piston, so that miss fire and abnormal combustion occur.

The purpose of this paper is to clarify the air motion of swirl flow in a reciprocating engine. The swirl velocities under motoring conditions were measured by a back scattered LDV using a bottom-view research engine. Experiments were conducted with three different combustion chambers having the same compression ratios. The results are as follows: (1) The swirl velocity in the cylinder increases in proportion to the engine speed. (2) The swirl velocity at the compression stroke increases due to the fact that the swirl flow is pushed into the cavity on the piston top. (3) At the compression TDC, the swirl ratio of a deep dish chamber is higher than the ratios of a pancake and a shallow dish chamber.

The magnetostatic resonance absorptions for an axially magnetized single crystal of YIG rod, [110] oriented, are observed in a waveguide and a cavity at 9.45 GHz. For the applied magnetic field ranging from 2800 to 3400 Oe resonance absorptions due to the dominant and third modes are observed but the second mode is not excited. The separation of these modes is conducted by comparing the transmitted power with the reflected microwave power pattern. For the dominant and third modes the relations between the field deviation, ΔH, from the cutoff field and the standing wave number n for each absorption are in good agreement between the theoretical and experimental values in a wide range of dc magnetic field. When the entire rod is inserted into the center of a waveguide or a cavity only the absorptions due to modes associated with an odd number, n, are observed for both dominant and third modes

Instabilities of spin waves in an axially magnetized YIG rod are studied in the volume magnetostatic and magnetoelastic regions using a spectrum analyzer. In the magnetoelastic region, the strength of the static magnetic field at which the resonance absorption occurs decreases with increasing input microwave power. When the input power reaches a threshold value, each absorption peak shows an abrupt jump and instabilities appear with oscillation frequencies of 300 kHz to 10 MHz. Instabilities may attribute to the second-order parametric process of the volume magnetostatic waves. In the magnetoelastic region, the intensities of the spectrum in lower sidebands are much larger than those in higher sidebands. However, in the volume magnetostatic region, the intensities of the spectrum in lower and higher sidebands have nearly equal amplitudes.

A square piston engine and a side-view collimating (SVC) cylinder engine are developed for side-view schlieren visualization of in-cylinder processes. The square piston engine has a square cylinder with two flat quartz windows permitting optical access to the entire cylinder volume. Compression sealing is provided by three polyimide ring assemblies which maintain the windows clean during the actual observational. In contrast with the square piston engine, the SVC cylinder engine permits to take schlieren photographs in practical engine geometries. This is made possible by designing the SVC cylinder so that it does not disperse parallel light rays.