Combinatorial MAB-Based Joint Channel and Spreading Factor Selection for LoRa Devices.

Long-Range (LoRa) devices have been deployed in many Internet of Things (IoT) applications due to their ability to communicate over long distances with low power consumption. The scalability and communication performance of the LoRa systems are highly dependent on the spreading factor (SF) and channel allocations. In particular, it is important to set the SF appropriately according to the distance between the LoRa device and the gateway since the signal reception sensitivity and bit rate depend on the used SF, which are in a trade-off relationship. In addition, considering the surge in the number of LoRa devices recently, the scalability of LoRa systems is also greatly affected by the channels that the LoRa devices use for communications. It was demonstrated that the lightweight decentralized learning-based joint channel and SF-selection methods can make appropriate decisions with low computational complexity and power consumption in our previous study. However, the effect of the location situation of the LoRa devices on the communication performance in a practical larger-scale LoRa system has not been studied. Hence, to clarify the effect of the location situation of the LoRa devices on the communication performance in LoRa systems, in this paper, we implemented and evaluated the learning-based joint channel and SF-selection methods in a practical LoRa system. In the learning-based methods, the channel and SF are decided only based on the ACKnowledge information. The learning methods evaluated in this paper were the Tug of War dynamics, Upper Confidence Bound 1, and ϵ-greedy algorithms. Moreover, to consider the relevance of the channel and SF, we propose a combinational multi-armed bandit-based joint channel and SF-selection method. Compared with the independent methods, the combinations of the channel and SF are set as arms. Conversely, the SF and channel are set as independent arms in the independent methods that are evaluated in our previous work. From the experimental results, we can see the following points. First, the combinatorial methods can achieve a higher frame success rate and fairness than the independent methods. In addition, the FSR can be improved by joint channel and SF selection compared to SF selection only. Moreover, the channel and SF selection dependents on the location situation to a great extent.

Appendiceal Perforation due to Migration of a Dental Instrument.

A 40-year-old male without any past medical history accidentally swallowed a titanium dental instrument (reamer) for root canal treatment. A cathartic was prescribed at a local hospital, and the course was observed. However, since the reamer was not excreted in feces, he was referred to our hospital. After admission, CT, lower gastrointestinal endoscopy, and barium enema revealed the migration of a foreign body into the appendix and its protrusion into the intraperitoneal cavity. As an emergency operation, laparoscopic appendectomy including the foreign body was performed. The following course was favorable without postoperative complications, and he was discharged on the 2nd hospital day. We report a patient with appendiceal perforation due to a foreign body (dental instrument for root canal treatment) in the appendix.

Results of pancreaticojejunal end-to-side anastomosis using the invagination method without a pancreatic stenting tube.

BACKGROUND/AIMS: Perioperative management of pancreaticoduodenectomy (PD) is a constant dilemma and challenging for gastrointestinal surgeons. Postoperative pancreatic fistula (POPF) and delayed gastric emptying (DGE) are of particular concern, and the onset of these conditions indicates a prolonged postoperative stay (POS). The procedure and postoperative outcomes of pancreaticojejunostomy performed at our hospital are reported. METHODOLOGY: POPF, DGE, and POS were investigated in 54 patients who had undergone PD at our hospital since June 2007. Pancreaticojejunal end-to-side anastomosis using the invagination method without a stenting tube and without duct-to-mucosa anastomosis was performed in all patients, regardless of pancreatic duct diameter. RESULTS: There were 26 patients (48.2%) without POPF, 24 (44.4%) with grade A, 4 (7.4%) with grade B, and none with grade C. The mean POS was 28.3 days. DGE was observed in 4 patients (7.4%) who underwent pylorus-preserving PD (PpPD). There were 34 patients with a soft pancreas. None of the patients experienced intraperitoneal bleeding or abscess, and no surgery-related deaths occurred. CONCLUSIONS: The reconstructive pancreaticojejunostomy procedure performed at our hospital appears to be safe and convenient, and we plan to collect additional data, including assessments of the function of the remaining pancreas, in the future.

Two cases of primary small cell carcinoma of the breast showing non-mass-like pattern on diagnostic imaging and histopathology.

Primary small cell carcinoma of the breast is a rare breast cancer. We report two cases of this entity showing a non-mass-like pattern on multimodality images and histopathology. Both women presented with a breast mass, and one had axillary lymphadenopathy. Both cases revealed fine calcification on mammography (MMG) and an irregularly shaped, hypoechoic lesion on ultrasonography. Computed tomography (CT) and magnetic resonance imaging (MRI) showed non-mass-like enhancement in both cases. Dynamic MRI showed medium initial enhancement followed by persistent delayed enhancement in one patient, whereas rapid initial enhancement with plateau delayed enhancement was observed in the other. The breast lesions showed very high signal intensity on diffusion-weighted MRI. Positron emission tomography showed moderate accumulation of 2-fluoro-2-deoxyglucose in the breast tumor and lymph node metastasis. The non-mass-like enhancement on CT and MRI and the segmental fine calcification on MMG indicate the abundance of components of ductal carcinoma in situ and the breast origin of the small cell carcinoma.

A case of perforated sigmoid diverticulitis in which gram staining of ascitic fluid was useful for diagnosis.

An 85-year-old woman was admitted to our hospital for steroid therapy for relapsing nephrotic syndrome. During hospitalization, she complained of sudden epigastric pain at night. Although there were signs of peritoneal irritation, CT showed a large amount of ascitic fluid, but no free intraperitoneal gas. Gram staining of ascitic fluid obtained by abdominal paracentesis showed Gram-negative rods, which raised a strong suspicion of gastrointestinal perforation and peritonitis. Therefore, emergency surgery was performed. Exploration of the colon showed multiple sigmoid diverticula, one of which was perforated. The patient underwent an emergency Hartmann's procedure. Imaging studies failed to reveal any evidence of gastrointestinal perforation, presenting a diagnostic challenge. However, a physician performed rapid Gram staining of ascitic fluid at night when laboratory technicians were absent, had a strong suspicion of gastrointestinal perforation, and performed emergency surgery. Gram staining is superior in rapidity, and ascitic fluid Gram staining can aid in diagnosis, suggesting that it should be actively performed. We report this case, with a review of the literature on the significance of rapid diagnosis by Gram staining.

Omental Infarction due to Omental Torsion.

Omental torsion is a rare cause of acute abdomen and sometimes requires surgery. Recently, we encountered a case of omental torsion diagnosed as omental infarction preoperatively. An 18-year-old male presented to our emergency room with a chief complaint of lower abdominal pain since previous 2 days. Because of his history of Down syndrome, an abdominal examination was very difficult. Plain abdominal computed tomography (CT) suggested omental hernia adhering to the right paracolic gutters. Two days after hospital admission, symptoms did not improve, and contrast-enhanced abdominal CT suggested omental infarction. We performed an emergency surgery. Upon exploration of the abdominal cavity, the greater omentum was found to be twisted four times and adhered to the right paracolic gutters. We performed a partial omentectomy. He was discharged 9 days after the surgery. There was no cause of omental torsion in the abdominal cavity, and he was diagnosed as having idiopathic omental torsion. In cases wherein the cause of acute abdomen cannot be detected, omental torsion should be considered, and abdominal CT could be helpful for the diagnosis.

Superior mesenteric vein thrombosis as a complication of acute appendicitis : report of a case.

Since superior mesenteric vein thrombosis (SMVT) is a relatively rare disease and shows no specific symptom, its diagnosis tends to be delayed. In this report, we present a patient in whom acute appendicitis was complicated by SMVT and portal vein thrombosis (PVT). A definitive diagnosis could be made by abdominal contrast-enhanced CT, and acute appendicitis was surgically treated. Anticoagulant therapy was continued for about half a year after surgery. Abdominal contrast-enhanced CT after discharge showed no recurrence of SMVT or PVT. We consider that acute appendicitis induced SMVT or PVT caused by the effect of inflammation. There is the possibility that these conditions lead to intestinal congestion or necrosis and liver dysfunction; appropriate diagnosis and treatment are necessary.

Detecting KRAS mutations in peripheral blood of colorectal cancer patients by peptide nucleic acid clamp PCR.

We investigated the effectiveness of peptide nucleic acid (PNA) clamp PCR for detecting KRAS mutations in peripheral blood samples of colorectal cancer (CRC) patients. We compared KRAS point mutations between tumour tissue and blood samples. Forty-two patients were included in this study. We observed KRAS mutations in formalin-fixed, paraffin-embedded tissues by PCR direct sequencing and in blood samples by PNA clamp PCR. KRAS point mutations were detected in primary tumour tissue samples of 13 patients (31.0%) and in peripheral blood samples of 10 patients (23.8%). KRAS point mutations were detected in both samples for 8 patients (19.0%). The sensitivity, specificity and accuracy for detecting KRAS mutations in peripheral blood and tumour tissue samples were 61.5, 93.1 and 83.3%, respectively. The positive and negative predictive values were 80.0 and 84.4%, respectively. Five patients with mutant KRAS in their plasma preoperatively, did not exhibit KRAS mutations postoperatively. Our method detected KRAS point mutations in peripheral blood samples of CRC patients, which contained extremely small amounts of mutant cells. This method is helpful for identifying metastatic CRC patients in whom metastases will respond to EGFR-targeted monoclonal antibody therapy.

The efficacy of intraoperative ultrasonography during laparoscopic cholecystectomy.

BACKGROUND/AIMS: Intraoperative ultrasonography (IOUS) has been used to delineate anatomy during laparoscopic cholecystectomy (LapC) and screen for common bile duct stones (CBDS), however no consensus about its efficacy has been reached in Japan. In this study, we compared and evaluated the performance of intraoperative cholangiography(IOC) and IOUS during LapC. METHODOLOGY: We evaluated 295 cases of cholecystolithiasis that underwent surgery from 2005- 2009 at our hospital. Frequency of CBDS and duration of surgery was examined in cases with IOC alone or IOC and IOUS in combination. RESULTS: There were 5 cases (1.7%) in which IOUS or IOC detected CBDS that had not been detected by preoperative evaluation using abdominal CT, abdominal ultrasonography or MRCP. Out of 62 LapC cases involving both IOC and IOUS, 60 cases showed the same findings, i.e. no false-negative results, indicating that IOUS is a trustworthy examination method. The mean duration of surgery involving IOUS alone was 135 minutes while a longer mean time of 163 minutes was found for that involving IOC alone or IOC and IOUS in combination. CONCLUSIONS: This study shows that IOC can be considered useful as it did not produce any false-negative results in screening CBDS and it also shortened the operation time. We also found some problems associated with IOC, such as small calculi falling within the gallbladder during examination procedures and the irradiation of patients and staff.

IgG4-related tumour-forming mastitis with histological appearances of granulomatous lobular mastitis: comparison with other types of tumour-forming mastitis.

AIMS: Sometimes, mastitis needs to be differentiated from carcinoma because of its association with induration and with ultrasound findings (such as low-echo lesions) that resemble those in carcinoma. The aim was to define this type of mastitis and to examine 18 cases to clarify its clinicopathological features. METHODS AND RESULTS: All cases were categorized into three types: non-specific mastitis with neutrophilic infiltration (n = 7); non-specific mastitis with lymphoplasmacytic infiltration (n = 9); and granulomatous lobular mastitis (n = 2). The three types of mastitis presented similar ultrasound findings and shared certain histological features including fibrosis and diffuse or lobulocentric inflammation. Granulomatous lobular mastitis showed specific clinicopathological features including lobulocentric inflammation with giant cells, diffuse IgG4+ plasma cells, and also a high level of serum IgG4. CONCLUSIONS: Granulomatous lobular mastitis could be categorized into IgG4-related and non-IgG4-related granulomatous lobular mastitis. IgG4 immunohistochemistry serum IgG4 might be useful for diagnosis of IgG4-related granulomatous lobular mastitis and could help to avoid overtreatment such as wide excision.

[A case of recurrent breast cancer responding to vinorelbine/trastuzumab combination therapy].

A 60-year-old woman with Stage II, ER-positive, PgR-positive, HER2 (2+) cancer in the right breast underwent right mastectomy with right axillary dissection after chemotherapy with EC followed by docetaxel (DOC) alone. Exemestane was used for postoperative adjuvant treatment. She underwent a right chest wall tumor resection for local recurrence. Hormone therapy was continued with toremifene in place of exemestane. In December 2007, two years after the second surgery, CEA was elevated and PET showed a local recurrence in the right chest wall and metastases to the right axillary nodes and liver. The tumor was ER-positive, PgR-negative and HER2 (3+) at recurrence, and vinorelbine/trastuzumab combination was initiated as first-line chemotherapy for the recurrent lesion and liver metastasis. All lesions in the right chest wall, right axillary nodes and liver disappeared from PET and CT images after five courses of the regimen, resulting in clinical CR. Vinorelbine combined with trastuzumab appears to be a useful therapy for HER2-positive recurrent breast cancer.

[A patient with recurrent rectal cancer in whom pulmonary metastasis disappeared by FOLFOX 4 therapy].

We performed FOLFOX 4 therapy in a patient with lung metastasis (a 62-year-old woman) after surgery for rectal cancer and observed both normalization of tumor markers and disappearance of the metastasis. Low anterior resection was performed for progressive rectal cancer, and treatment with UFT and folinate was started one month after surgery. However, tumor markers increased after 2 months of treatment and CT scans showed metastases to both lungs. FOLFOX 4 therapy was started, and tumor markers became normal after four courses, while the lung metastases disappeared after 10 courses. The dosage of FOLFOX 4 was reduced after three courses due to neutropenia and diarrhea. This treatment appeared to be effective for the inhibition of lung metastasis associated with colorectal cancer.

Massive melena caused by a carcinoid of the small intestine: report of a case.

We report a case of massive melena caused by a carcinoid of the small intestine. A 28-year-old woman was admitted to our department after presenting with massive melena. The source of the bleeding could not be localized by upper or lower gastrointestinal endoscopy, computed tomography (CT), or labeled red blood cell scintigraphy. Enteroscopy allowed visualization only up to the jejunum, and we could not localize the lesion. The melena subsided with conservative treatment, but the patient was readmitted 4 months later when she suffered another episode of massive melena. A contrast CT scan performed immediately showed extravascular leakage and the retention of contrast medium in the ileum. Thus, she underwent an emergency surgery, during which endoscopy confirmed a small ileal tumor accompanied by pulsating bleeding from the exposed blood vessels at its center. The small intestine was partially resected, including the swollen lymph nodes, the size of small beans. Pathological examination confirmed a carcinoid tumor 1 cm in diameter, with an arterial rupture at its center and lymph node metastasis.

Development of an automated water toxicity biosensor using Thiobacillus ferrooxidans for monitoring cyanides in natural water for a water filtering plant.

An on-line biosensor consisting of immobilized Thiobacillus ferrooxidans and an oxygen electrode was developed for automated monitoring of acute toxicity in water samples. T. ferrooxidans is an obligatory acidophilic, autotrophic bacterium and derives its energy by the oxidation of ferrous ion, elemental sulfur, and reduced sulfur compounds including metal sulfides. The assay is based on the monitoring of a current increase by addition of toxicoids, which is caused by the inhibition of bacterial respiration and decrease in oxygen consumption. Optimum cell number on the membrane was 5.0 x 10(8) cells. The steady-state current was obtained when concentration of FeSO4 was above 3.6 mM at pH 3. The sensor response of T. ferrooxidans immobilized membrane for 5.0 microM KCN was within an error of 10% for 30 membranes. A linear relationship was obtained at KCN concentration in the range of 0.5-3.0 microM in a flow-type monitoring system. Minimum detectable concentrations of KCN, Na2S, and NaN3 were 0.5, 1.2, and 0.07 microM, respectively. The monitoring system contained two biosensors and these sensors were cleaned with sulfuric acid (pH 1.5) twice a day. This treatment could remove fouling on microbial immobilized membrane by natural water and ferrous precipitation in the flow cell. This flow-type monitoring sensor was operated continuously for 5 months. Also, T. ferrooxidans immobilized membrane can be stored for one month at 4 degrees C when preserved with wet absorbent cotton under argon gas.