Pancreatic neuroendocrine carcinoma in a pregnant woman:A case report and review of the literature

BACKGROUND Portal venous thromboembolism caused by malignant pancreatic neuroendocrine tumor metastasis,as the initial presentation of portal hypertension and upper gastrointestinal bleeding,is a rare entity.To our knowledge,there are no reports of this entity in pregnant women.We describe a case of pancreatic neuroendocrine carcinoma during pregnancy with hematemesis and hematochezia as the initial presentation and review the literature to analyze the demographic,clinical,and pathological features to provide a reference for clinical diagnosis and treatment.CASE SUMMARY A 40-year-old woman presented with hematemesis and hematochezia at 26-wk gestation;she had no other remarkable medical history.The physical examination revealed normal vital signs,an anemic appearance,and lower abdominal distension.Abdominal color Doppler ultrasonography showed portal vein thrombosis,splenomegaly,intrauterine pregnancy,and intrauterine fetal death.Esophagogastroduodenoscopy revealed esophageal and gastric varicose veins and portal hypertensive gastropathy.Contrast-enhanced computed tomography demonstrated multiple emboli formation in the portal and splenic veins,multiple round shadows in the liver with a slightly lower density,portal vein broadening,varicose veins in the lower esophagus and gastric fundus,splenomegaly,bilateral pleural effusion,ascites and pelvic effusion,broadening of the common bile duct,and increased uterine volume.According to the results of Positron emission tomography-computed tomography and immunohistochemical staining,the final diagnoses were that the primary lesion was a pancreatic neuroendocrine tumor and that there were secondary intrahepatic metastases and venous cancer thrombogenesis.CONCLUSION Upper gastrointestinal bleeding in a pregnant woman may be caused by portal hypertension due to a malignant pancreatic neuroendocrine tumor.

Synthesis and Characterization of UPPE-PLGA-rhBMP2 Scaffolds for Bone Regeneration

A novel unsaturated polyphosphoester(UPPE) was devised in our previous research,which is a kind of promising scaffold for improving bone regeneration.However,the polymerization process of UPPE scaffolds was unfavorable,which may adversely affect the bioactivity of osteoinductive molecules added if necessary,such as recombinant human bone morphogenetic protein-2(rhBMP2).The purpose of this study was to build a kind of optimal scaffold named UPPE-PLGA-rhBMP2(UPB) and to investigate the bioactivity of rhBMP2 in this scaffold.Furthermore,the cytotoxicity and biocompatibility of UPB scaffold was assessed in vitro.A W1/O/W2 method was used to fabricate PLGA-rhBMP2 microspheres,and then the microspheres were added to UPPE for synthesizing UPB scaffold.The morphological characters of PLGA-rhBMP2 microspheres and UPB scaffolds were observed under the scanning electron microscopy and laser scanning confocal microscopy.The cumulative release of UPB scaffolds was detected by using ELISA.The cytotoxicity and biocompatibility of UPB scaffolds were evaluated through examining the adsorption and apoptosis of bone marrow stromal cells(bMSCs) seeded on the surface of UPB scaffolds.The bioactivity of rhBMP2 in UPB scaffolds was assessed through measuring the alkaline phosphates(ALP) activity in bMSCs seeded.The results showed that UPB scaffolds sequentially exhibited burst and sustained release of rhBMP2.The cytotoxicity was greatly reduced when the scaffolds were immersed in buffer solution for 2 h.bMSCs attached and grew on the surface of soaked UPB scaffolds,exerting well biocompatibility.The ALP activity of bMSCs seeded was significantly enhanced,indicating that the bioactivity of rhBMP2 remained and still took effect after the unfavorable polymerization process of scaffolds.It was concluded that UPB scaffolds have low cytotoxicity,good biocompatibility and preserve bioactivity of rhBMP2.UPB scaffolds are promising in improving bone regeneration.

Flexible assistance strategy of lower limb rehabilitation exoskeleton based on admittance model

Exercise training based on exoskeleton is an effective rehabilitation method for stroke patients. However, some rehabilitation exoskeletons still have poor wearable performance and obvious human-robot impedance during training, which easily cause secondary injuries to the patients. In this study, a variable admittance control strategy is proposed to improve the operator's wearable comfort, which can adapt to different operators by regulating admittance parameters. The admittance controller has two feedback loops: the position inner-loop and the admittance outer-loop. Meanwhile, the exoskeleton Lagrange model is constructed with unknown friction disturbance. By using Lyapunov technique and backstepping with state observer, the joint position error of exoskeleton is convergence into a zero neighborhood. The effectiveness of the proposed admittance controller is verified by both simulation and experiment. The tracking error of hip and knee joint is less than 4 degrees while the human-robot interaction torque is constrained in a tolerable range of the operator.

Gas Leakage Detection and Pressure Difference Identification by Asymmetric Differential Pressure Method

Currently,the measurement methods for pneumatic system leakage include bubbling,ultrasonic,and pressure detection methods.These methods are sensitive to high-precision sensors,long detection times,and stable external environments.The traditional differential pressure method involves severe differential pressure fluctuations caused by environmental pressure fluctuations or electromagnetic noise interference of sensors,leading to inaccurate detection.In this paper,a differential pressure fitting method for an asymmetric differential pressure cylinder is proposed.It overcomes the limitation of the detection efficiency caused by the asynchronous temperature recovery of the two chambers in the asymmetric differential pressure method and uses the differential pressure substitution equation to replace the differential calculation of the differential pressure.The improved differential pressure method proposes an innovation based on the detection principle and calculation method.Additionally,the influence of the parameters in the differential pressure substitution equation on the leakage calculation results was simulated,and the specific physical significance of the parameters of the differential pressure substitution equation was explained.The experiments verified the fitting effect and proved the accuracy of this method.Compared with the traditional differential pressure method,the maximum leakage deviation of inhibition was 0.5 L/min.Therefore,this method can be used to detect leaks in air tanks.

Application of dynamic recrystallization model in AZ12 magnesium alloy rolling process

To deeply understand the dynamic recrystallization behavior of as-cast AZ12 magnesium alloy in deformation process,the uniaxial hot compression experiments were implemented through systematic isothermal compression experiments.The true strain of thermal compression experiments was set to 50%with temperatures of 200,250,300,350,400℃and the strain rates of 0.001,0.01,0.1,1 s^(-1).The Dynamic Recrystallization(DRX)kinetic model of AZ12 magnesium alloy was established and the accuracy of this model was verified.The model is used to predict the volume fraction of the sheet obtained by rolling through different rolling passes under the condition of consistent total reduction(50%).And the predicted results are in good agreement with the experimental results.

Highly fluorescence Ta_(4)C_(3) MXene quantum dots as fluorescent nanoprobe for heavy ion detection and stress monitoring of fluorescent hydrogels

Compared with other transition metal Mxene derived quantum dots(MQD_(S)),Ta-based Mxene quantum dots have good functionality,but Ta-based Mxene quantum dots and their applications have not been studied so far.In this paper,we report for the first time the synthesis of high fluorescence quantum yield(QY) N-doped Ta_(4)C_(3) quantum dots(N-MQDs) using Ta_(4)C_(3) quantum dots in acid reflux damaged Ta_(4)C_(3) nanosheets as precursors and ethylenediamine as nitrogen source.The prepared N-MQDs have excellent blue photoluminescence(PL) properties,particle size is only 2.60 nm,QY is up to 23.4%,and good stability.In addition,it has been reported that N-MQDs can be used as fluorescent probe for detection of Fe;and remote force sensing analysis In liquid ion sensing,N-MQDS shows a unique selective quenching of Fe;with a detection limit as low as 2 μmol/L,and has great potential as a fast and super-sensitive fluorescent probe for the detection of heavy ion.More importantly,in solid mechanics sensing,the introduction of N-MQDs into self-healing hydrogels can be developed into a fluorescent hydrogel that can be used for accurate remote force measurement and applied in the field of mechanical sensing analysis.Therefore,Ta-based N-MQDs show excellent potential in the field of fluorescence sensing,which provides a door for multi-dimensional sensing of new materials in the future.