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Presents a study that developed a novel ridge waveguide laser diode in which the ridge is buried in a newly developed polyimide with a low thermal expansion coefficient. Examples of index-guided laser structure; Uses of a polymide; Details of the fabrication process.

Investigates the reduction of aluminum-gallium arsenide growth temperature by employing migration enhanced epitaxy (MEE). Information on the MEE method; Details on the experiment; Conclusion.

Resonant tunneling and accompanying negative differential resistance are observed at 85 K in Al0.4Ga0.6As/GaAs triple barrier diodes, where two GaAs wells are separated by three AlGaAs barriers. Five resonance peaks, one small peak for one bias polarity, one medium and one large peak for each bias polarity, are observed. These are the resonance current peaks from the ground level of a populated well to the ground, the first excited or the second excited level of an adjoining unpopulated well. These are the direct electrical observations of the resonant tunneling between confined electron states in two potential wells of a semiconductor multiheterostructure. [ABSTRACT FROM AUTHOR]

A short-period (AlGaAs)m(GaAs)n superlattice has been applied to the barrier layers in a single and a multiple quantum well structure prepared by molecular beam epitaxy in order to improve the interface quality. With a 38 Å thin GaAs quantum well without employing aluminum, a low threshold current density of 260 A/cm2, a high characteristic temperature (T0) of 205 K, and a high differential quantum efficiency of 75% have been achieved in a double quantum well ridge waveguide laser diode emitting at 780 nm. [ABSTRACT FROM AUTHOR]

AlGaAs layers with a featureless specular surface morphology were grown successfully on an exactly (111)B oriented GaAs substrate by migration-enhanced epitaxy (MEE) even at growth temperatures below 500 °C. We have also observed reflection high-energy electron diffraction (RHEED) intensity oscillation of AlGaAs on a (111)B oriented substrate by MEE. The single quantum well (SQW) is prepared by MEE on a (111)B and a (100) substrate simultaneously, and the photoluminescence intensity from (111) SQW is shown to be about 50 times higher than that from (100) SQW. [ABSTRACT FROM AUTHOR]

A woman in her 90s underwent laparoscopic hernia repair for a recurrent left inguinal hernia with abdominal wall defect 2 years ago. She came to our department with a complaint of a mass in the hernia wound, which was suspected to be a skin cancer, and the pathology diagnosis was adenocarcinoma. A colonoscopy was performed and she was diagnosed with sigmoid rectal cancer with only skin metastasis and the operation was performed. Laparoscopic anterior resection of the rectum, excision of the skin tumor, mesh removal, and rectus abdominis skin grafting were performed, and these were radical surgery. Simultaneous cutaneous metastasis of rectal cancer is extremely rare, being part of the 2.0% of other sites, and is reported with some literature review.

A 78-year-old man who was diagnosed as having hepatocellular carcinoma(segment 4/8)underwent laparoscopic hepatectomy. About 5 hours after the start of the operation, SpO2 and systolic blood pressure suddenly dropped to 87% and 40 mmHg. EtCO2 level decreased to 8 mmHg and PaCO2 was 48.5 mmHg. Based on the discrepancy between the PaCO2 and EtCO2, the patient was diagnosed as having pneumoperitoneum-induced carbon dioxide embolism. The surgical procedure was immediately interrupted and the patient was hyperventilated with pure oxygen. After surgical interruption, general status was recovered to the normal condition. We carefully restarted the operation and completed it laparoscopically. The patient was discharged from the hospital on the 15th day without any postoperative complications. Carbon dioxide embolization is a serious life-threatening complication that requires careful monitoring.

A woman in her 80s, had undergone radical surgery for an endometrial carcinoma 9 years earlier, and her 5-year postoperative follow-up had been completed without recurrence. She consulted an orthopedic surgeon with a chief complaint of a mass in the left inguinal region, and was referred to surgery after MRI scan revealed lymph node metastases in the left inguinal and external iliac region and a sigmoid colon tumor. Due to postoperative adhesion of the uterine cancer, the colonoscope could not be inserted to the tumor, and no tissue diagnosis was made. CT and PET scans revealed a sigmoid colon tumor plus periungual lymph node metastasis, and it was determined that radical surgery was possible, and the patient underwent resection. Surgery was performed by laparoscopic resection of the sigmoid colon and lymphadenectomy, with R0 resection. The sigmoid colon tumor and lymph nodes were of the same histology as the 9-year-old endometrial carcinoma, leading to the diagnosis of colon and lymph node recurrence 9 years after endometrial carcinoma surgery.

A 64-year-old woman underwent right hemicolectomy for transverse colon cancer. Histopathological findings revealed T, type 2, 24×22 mm, tub2, pT2N1a(1/23)M0, and pStage Ⅲa. Postoperative adjuvant chemotherapy was not administered at the patient's request. One year after surgery, carcinoembryonic antigen(CEA)level was elevated, and Gd-EOB-DTPA- enhanced MRI revealed a nodule in segment 2 and 4/8 of the liver. Based on the diagnosis of hepatic metastasis, laparoscopic partial hepatectomy was performed. Three years after hepatectomy, CEA level was found to be elevated again, and chest CT showed a solitary pulmonary nodule in segment 7 of the right lung. With a diagnosis as pulmonary metastasis, FOLFIRI plus bevacizumab was performed. After 41 courses of FOLFIRI plus bevacizumab, the pulmonary nodule decreased in size, and no new lesions appeared. The chemotherapy was terminated at the patient's request. Six months later, the pulmonary nodule increased in size, and thoracoscopic partial pulmonary resection was performed. Hepatic and pulmonary resection specimens were histopathologically consistent as metastasis of colorectal cancer. The patient has been alive without recurrence for about 4 years after final surgery(pulmonary resection)without postoperative adjuvant chemotherapy. We report a case of long-term survival with metachronous hepatic and pulmonary metastases from transverse colon cancer by multidisciplinary treatment.

Our patient was a man in his 70s who underwent proximal gastrectomy with double tract reconstruction in 2013. He was diagnosed with cStage Ⅳ unresectable remnant gastric cancer with paraaortic lymph node metastases in 2021. He was treated with 5 courses of S-1 plus oxaliplatin therapy. Computed tomography revealed that the lymph node metastases had decreased in size after treatment. We performed conversion surgery and achieved R0 resection. Furthermore, the elevated jejunum was preserved and total gastrectomy was possible without re-anastomosis. Postoperative adjuvant chemotherapy with S-1 was started and he remains alive without recurrence at 6 months postoperative.

The patient was 40s male, who underwent laparoscopic low anterior resection for his upper rectal cancer with final pathology results of tub2, pT3(SS), no lymph metastasis and fStage Ⅱ. He was followed up without adjuvant chemotherapy. Half a year after surgery, tumor marker was elevated and CT scan revealed multiple liver metastases. He was treated with oxaliplatin, irinotecan, Leucovorin and 5-fluorouracil(FOLFOXIRI)plus bevacizumab because of RAS mutant type. In the third courses, he has pain in the lower extremities and was diagnosed with acute lower extremity arterial occlusion. Subsequently, chemotherapy was resumed with the exception of bevacizumab, in combination with DOAC, which resulted in tumor shrinkage and allowed resection of the liver metastases.

Case 1 is a 56-year-old man. During postoperative adjuvant chemotherapy for pancreatic cancer, weakness in the right upper and lower limbs appeared, and a head CT scan was performed, but no abnormal findings were noted. Diffusion- weighted MRI scan of the head showed multiple cerebral infarcts, and a diagnosis of Trousseau syndrome was made. Case 2 is an 86-year-old man. During chemotherapy for postoperative recurrence of distal bile duct carcinoma, he developed weakness in the right upper and lower limbs, and a head MRI scan was performed. Diffusion-weighted MRI showed scattered high-signal areas, and a diagnosis of Trousseau syndrome was made. Trousseau syndrome is a condition in which stroke is caused by hypercoagulability associated with malignant tumor. The initial symptoms of cerebral infarction in patients with cancer are similar to those of chemotherapy-induced adverse events and brain metastases, and therefore, a head MRI scan is recommended even if there is no obvious abnormality on head CT scan.

The patient was a 74 year-old woman. She came to the hospital with the chief complaint of vomiting, difficulty walking, and disorientation. The MRI study showed increased FLAIR and DWI signals in the bilateral medial thalamus. Abdominal enhanced CT scan showed a 2.4 cm tumor in the jejunum. And ileus due to small intestinal tumor was observed. She diagnosed Wernicke's encephalopathy associated with gastrointestinal transit disorder. Vitamin B1 300 mg/day for 3 days was started, and eye movements and disorientation improved on the day following the start of administration. On the 10th day after admission, partial resection of the small intestine was performed for a small intestinal tumor. She was diagnosed as small intestinal cancer. She was transferred to the hospital on the 20th postoperative day.

Introduction: Control of postoperative gastroesophageal reflux (GER) is a critical consideration for patients who undergo proximal gastrectomy. This report describes a new and simple reconstruction method by esophagogastrostomy with placement of the remnant stomach into the lower mediastinum (EG-PRIME). This approach not only suppresses postoperative GER, but it can also be easily performed by total laparoscopy. Detailed herein are the methods for EG-PRIME and the results for three patients with cancer of the upper gastric body., Materials and Surgical Technique: At the start of the EG-PRIME surgical procedure, a pseudo-fornix and lozenge-shaped gastric conduit were made by cutting the stomach diagonally. Next, the pseudo-fornix was inserted into the esophageal hiatus to form a new angle of His. Then overlap anastomosis was performed and the entry site was closed longitudinally. The outcomes assessed were operative time, intraoperative blood loss, postoperative complications and GER according to 24-hour pH monitoring., Discussion: The operative times were 339, 288 and 236 minutes; in two patients, intraoperative blood loss was 260 and 343 mL, and in the third, blood loss was minimal. No postoperative complications were observed in any of the three patients. The degree of the GER resulting in fraction time pH<4 was 9.0%, 0.3%, and 2.9%, respectively. No esophagitis by upper gastrointestinal endoscopy was observed in any patient. This EG-PRIME method was technically feasible for reconstruction after proximal gastrectomy by total laparoscopy. This approach may be as simple and useful as esophagogastrostomy for preventing postoperative GER, but more experience with this method is required., (© 2020 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.)

We report a case of gastrointestinal submucosal tumor with an intraluminal growth pattern resected by laparoscopic wedge resection. A 62-year-old man was admitted because of melena. Upper gastrointestinal endoscopy revealed gastrointestinal submucosal tumor with an intraluminal growth pattern just below the gastric junction, and the pathological diagnosis was GIST. A laparoscopic wedge resections(percutaneous endoscopic intragastric surgery)was performed by a single access port. After laparotomy 5 cm above the umbilicus, the anterior wall of the middle part of the stomach was incised and fixed to the skin, and the tumor was dissected with a linear stapler. The final pathology result showed a high risk GIST of 70×40 mm with 110 mitotic images/50 HPF, and the patient was treated with imatinib mesylate adjuvant chemotherapy. There were no complications, including postoperative transit disturbances, and there were no local or distant metastatic recurrences.

Background: Since delirium has various adverse effects in patients with malignant tumors, it is important to eliminate the cause. We investigated delirium in patients with malignant tumors., Method: Seventy seven malignant tumor patients who admitted to palliative care unit from May 2015 to March 2016 were subjected to a retrospective analysis of delirium., Results: Delirium was present in 17 patients(22.1%)on admission, and in 38 patients(49.4%)before discharge. After hospitalization, delirium improved without relapse in 5 patients(29%)and the onset of delirium was avoided in 34 patients(57%). Factors of delirium at admission were nausea and day/night reversal, factors of delirium at discharge were dementia, pain, and day/night reversal., Conclusions: In the present study, we investigated the causes and course of delirium in patients with malignant tumors.

A 60-year-old female visited our hospital due to anorexia and jaundice in March 2016. She underwent pancreatoduodenectomy( PD)and was diagnosed with distal bile duct cancer. The histopathological diagnosis was distal bile duct cancer, tub2, pT3aN1M0, pStage ⅡB. Postoperatively, she received S-1 therapy as adjuvant chemotherapy. One year after surgery, abdomi- nal enhanced CT and EOB-MRI revealed a liver metastasis(S3; 20mm). After 4courses of gemcitabine(GEM)/cisplatin(CDDP) combination therapy, there was no new lesion; thus, we performed partial hepatectomy(S3)in July 2017. The histopathology findings revealed well differentiated adenocarcinoma that was similar to the primary lesion, and the tumor was confirmed as a recurrence of bile duct cancer. She remains alive without second recurrence for 2 years since the tumor resection(about 3 years since PD). Surgical intervention might be beneficial in selected patients with recurrent bile duct cancer.