On March 11, 2011, a massive earthquake (magnitude 9.0) and accompanying tsunami hit the Tohoku region of eastern Japan. Since then, the Fukushima Daiichi Nuclear Power Plants have been facing a ...crisis due to the loss of all power that resulted from the meltdown accidents. Three buildings housing nuclear reactors were seriously damaged from hydrogen explosions, and, in one building, the nuclear reactions became out of control. It was too dangerous for humans to enter the buildings to inspect the damage because radioactive materials were also being released. In response to this crisis, it was decided that mobile rescue robots would be used to carry out surveillance missions. The mobile rescue robots needed could not be delivered to the Tokyo Electric Power Company (TEPCO) until various technical issues were resolved. Those issues involved hardware reliability, communication functions, and the ability of the robots' electronic components to withstand radiation. Additional sensors and functionality that would enable the robots to respond effectively to the crisis were also needed. Available robots were therefore retrofitted for the disaster reponse missions. First, the radiation tolerance of the electronic componenets was checked by means of gamma ray irradiation tests, which were conducted using the facilities of the Japan Atomic Energy Agency (JAEA). The commercial electronic devices used in the original robot systems operated long enough (more than 100 h at a 10% safety margin) in the assumed environment (100 mGy/h). Next, the usability of wireless communication in the target environment was assessed. Such tests were not possible in the target environment itself, so they were performed at the Hamaoka Daiichi Nuclear Power Plants, which are similar to the target environment. As previously predicted, the test results indicated that robust wireless communication would not be possible in the reactor buildings. It was therefore determined that a wired communication device would need to be installed. After TEPCO's official urgent mission proposal was received, the team mounted additional devices to facilitate the installation of a water gauge in the basement of the reactor buildings to determine flooding levels. While these preparations were taking place, prospective robot operators from TEPCO trained in a laboratory environment. Finally, one of the robots was delivered to the Fukushima Daiichi Nuclear Power Plants on June 20, 2011, where it performed a number of important missions inside the buildings. In this paper, the requirements for the exploration mission in the Fukushima Daiichi Nuclear Power Plants are presented, the implementation is discussed, and the results of the mission are reported.
Background
Mycobacterium chelonae
, a nontuberculous mycobacterium, commonly causes skin, soft tissue, eye, pulmonary, catheter-related, and post-surgical infections in patients with ...immunosuppression or trauma.
M. chelonae
breast infections are rare, and most cases occur following cosmetic surgery. Here, we report the first case of spontaneous breast abscess due to
M. chelonae
.
Case presentation
A 22-year-old Japanese woman presented at our hospital with swelling and pain in the right breast for the past 2 weeks without any fever. She had a 19-month-old child and stopped breastfeeding 1 month after giving birth. The patient had no history of trauma or breast surgeries, no family history of breast cancer, and was not immunocompromised. Breast ultrasonography revealed a heterogeneous hypoechoic lesion with multiple fluid-filled areas suspected to be abscesses. Dynamic contrast-enhanced magnetic resonance imaging revealed a 64 × 58 × 62 mm, ill-defined, high-signal-intensity lesion with multiple ring enhancements in the upper half of the right breast. The first diagnosis was inflammatory breast cancer or granulomatous mastitis with abscess. A core needle biopsy led to drainage of pus. Gram staining did not reveal any bacteria in the pus, but the colonies from the biopsy grew on blood and chocolate agar cultures. Mass spectrometry detected
M. chelonae
in these colonies. Histopathological findings revealed mastitis without malignancy. The patient's treatment regimen was oral clarithromycin (CAM) based on susceptibility. Three weeks later, although the pus had reduced, the induration in the breast did not resolve; therefore, multidrug antibiotic treatment was initiated. The patient received amikacin and imipenem infusion therapy for 2 weeks, followed by continuation of CAM. Three weeks later, tenderness in the right breast recurred with slight pus discharge. Hence, minocycline (MINO) was added to the treatment. The patient stopped CAM and MINO treatment 2 weeks later. There was no recurrence 2 years after treatment.
Conclusion
We report a case of
M. chelonae
breast infection and abscess formation in a 22-year-old Japanese woman without obvious risk factors.
M. chelonae
infection should be considered in cases of intractable breast abscess, even in patients without immunosuppression or trauma.
We describe a case of cardiac compression caused by an esophageal hiatal hernia that resulted in circulatory failure and cardiac arrest. Computed tomography revealed gastric herniation into the ...mediastinum, with marked cardiac compression. Cardiopulmonary resuscitation was performed, and a nasogastric tube was inserted for gastric decompression, which resulted in the return of spontaneous circulation and subsequent hemodynamic stabilization.
Background
Esophageal hiatal hernia is commonly encountered in clinical practice. We describe a case of cardiac compression caused by an esophageal hiatal hernia that resulted in circulatory failure and cardiac arrest.
Case Presentation
An 82‐year‐old woman presented to our hospital with vomiting, which progressed to cardiac arrest in the emergency room after computed tomography (CT) imaging. CT revealed gastric herniation into the mediastinum, with marked cardiac compression. Cardiopulmonary resuscitation was performed, and a nasogastric tube was inserted for gastric decompression, which resulted in the return of spontaneous circulation and subsequent hemodynamic stabilization. However, the patient died of aspiration pneumonia 4 days later.
Conclusion
Gastric decompression can lead to rapid improvements in respiration and circulation in patients with an esophageal hiatal hernia. Nonetheless, to prevent complications, such as those observed in our patient, definitive surgical treatment is warranted.
The patient was a 67-year-old man who had undergone sigmoid colectomy for sigmoid colon cancer 20 years ago. Six years after the operation, subtotal stomach-preserving pancreaticoduodenectomy ...(gastropancreatic anastomosis) was performed for recurrence in pancreatic head lymph nodes. He was hospitalized for pancreatitis, but hematemesis appeared after admission and endoscopy was performed. The gastric mucosa turned black, suggesting gastric ischemia. Contrast-enhanced CT revealed poor contrast in the stomach, pancreas and spleen, and emergency surgery was performed for suspected multi-organ necrosis. However, no necrosis was observed, so an intestinal fistula was constructed and the operation was completed. CT on day 20 of illness revealed a gastrosplenic fistula and splenic abscess. We attempted conservative treatment and performed CT-guided drainage for splenic abscess. The splenic abscess shrank, but the fistula remained and did not improve easily. On day 79, gastrosplenic fistula closure and splenectomy were performed, and the patient was discharged on day 122. We report this case as a rare example of gastrosplenic fistula, since only one previous case of this condition has been reported in the Central Medical Journal.
A 79-year-old man visited our hospital due to melena. He had undergone low anterior resection for rectal cancer ten years ago. Abdominal contrast-enhanced CT revealed arteriovenous malformation (AVM) ...in the pelvis. Colonoscopy showed bleeding at the previous anastomotic site. Interventional radiology (IVR) was performed for treatment. Angiography of the right common iliac artery revealed AVM of the internal iliac artery region. Embolization of the main feeding artery was performed. After the procedure, melena stopped and the patient was discharged, but was then readmitted due to re-bleeding on the next day. Transanal suture of the bleeding site was performed. Based on a tentative conclusion that the bleeding had stopped, the patient was transferred to an IVR specialty facility for curative treatment of AVM. Hemostasis was obtained by embolizing multiple inflow arteries and outflow veins. There has been no recurrence for two years after treatment.
This letter describes a wall deadlock evasion method for tracked vehicles. Wall deadlock is a phenomenon where the robot cannot rotate to the commanded direction when it collides with a wall, because ...the motion is restricted by the wall. The key idea behind solving this problem involves an adjustment of the rotation radius to generate sufficient rotational moment. There are several approaches to generate a rotational moment; however, no previous solution has been established to address this problem by adjusting the rotation radius based on the dynamics of wall deadlock. In this letter, the authors propose a new wall deadlock evasion method based on the sufficient rotation radius estimation. Experimental results show that the robot can generate rotational motion that satisfies conditions expected by the model. The wall deadlock evasion method is implemented and shows improved performance in terms of reproducibility of motion compared with the different approach proposed in our previous work. Wall deadlock evasion provides more choices of motion such as being as close to the obstacles as possible and ensures that the robot can continue locomotion after such motion. By handling wall deadlock, the robots can utilize surrounding walls for motion in situations such as relative positioning or driving in fixed lanes.
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