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The accuracy of attitude and heading measurement, as well as the system real-time performance are basic indicators used to evaluate an attitude and heading reference system (AHRS). In order to improve the attitude and heading measurement accuracy under dynamic complex environment, the AHRS system should also have numerical stability and calculation robustness. The AHRS system based on MEMS multi-sensor fusion can realize fusion processing of data measured by multiple sensors, so as to calculate and obtain the optimal carrier attitude and heading information, conduct real-time output, and improve the accuracy and reliability of attitude and heading measurement. For the AHRS system consisting of MEMS gyroscope, accelerometer and triaxial magnetometer, attitude and heading detection principle and algorithm based on MEMS multi-sensor fusion were proposed in this study: The information of the system itself was firstly used to discriminate motion state of the carrier within the filtering cycle, and then Kalman filtering was conducted using different measured information according to motion state to correct the attitude error angle caused by gyroscopic drift. On this basis, an attitude fusion algorithm based on extended Kalman filtering technology was designed for time update process of Kalman filtering, output information of accelerometer was taken as observed quantity under certain conditions to realize measurement updating process of Kalman filtering, and then attitude angle was calculated. In an optical fiber attitude and heading system project in practical engineering, a vehicle field test analysis was carried out simultaneously with the system using ordinary attitude algorithm, and the results showed that the extended Kalman filtering algorithm designed according to the simulation results could realize multi-sensor information fusion, improve measurement accuracy and realize accurate attitude positioning, so as to provide simpler and more flexible criteria for carrier motion status. The results have verified the accuracy and reliability of the algorithm, so it is feasible in practical engineering.

Rationale:Rectal neuroendocrine tumor is a rare disease that is difficult to diagnose by clinical and imageological examinations. The treatment of rectal neuroendocrine tumors is still controversial.Patient concerns:A 50-year-old woman complained of abdominal pain beneath the xiphoid process for 1 day. Physical checkup revealed tenderness at the right upper abdomen. A fecal occult blood test was positive. MRI showed an occupation lesion in the right lobe of the liver. Colonoscopy examination showed a lesion at the lower rectum with an ulcerated surface that was tough in texture. No abnormality was found in the tumor markers.Diagnosis:Rectal neuroendocrine tumor (G3) with liver metastasis.Interventions:Neoadjuvant chemotherapy followed by laparoscopic surgery was given.Outcomes:The patient followed up regularly in the outpatient department for 13 months after surgery, and no sign of recurrence was found.Lessons:Neoadjuvant chemotherapy followed by laparoscopic surgery is a new idea for the treatment of rectal neuroendocrine carcinoma with distant metastasis, which offers favorable conditions for saving the anus during the surgery to enhance the patient's quality of life.

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The incidence of appendiceal stump leakage (ASL) is extremely low and heterogeneous, which has been reported to be approximately 0.5%–1.0%. It is a catastrophic complication with high mortality rate despite its low morbidity. Once it occurs, it will put the doctor in a passive position because dealing with the leakage is much more cumbersome than appendectomy. We extensively reviewed the literature on ASL, focusing on the management and prognosis. Unsurprisingly, all of the physicians advocated extended resection, which apparently gave them sufficient confidence. However, partial cecum resection, cecostomy, or terminal ileectomy is extremely invasive and destructive. So, the patients had to experience great mental and physical trauma, longer hospital stays, higher rates of wound infection, more costs, and even a third surgery. Therefore, are there any better approaches for ASL? In this article, we report a case of ASL who successfully underwent endoscopic treatment. A 70-year-old male was admitted with gangrenous perforated appendicitis with a large iliopsoas abscess. Appendectomy, iliopsoas abscess debridement and sufficient drainage, appendicular stump repair and closure, and terminal ileostomy were performed. Three months later, the patient was readmitted and the stoma reversal was performed as scheduled. Seven days later, ASL was found when a liquid diet was applied routinely due to right lower quadrant pain and low fever. Finally, with the periappendiceal abscess completely drained, we clamped the appendiceal orifice with five titanium clips under an electronic colonoscope, which eventually sealed the leakage and avoided extended resection.