Preliminary exploration of animal models of congenital choledochal cysts

BACKGROUND Various animal models have been used to explore the pathogenesis of choledochal cysts(CCs),but with little convincing results.Current surgical techniques can achieve satisfactory outcomes for treatment of CCs.Consequently,recent studies have focused more on clinical issues rather than basic research.Therefore,we need appropriate animal models to further basic research.AIM To establish an appropriate animal model that may contribute to the investigation of the pathogenesis of CCs.METHODS Eighty-four specific pathogen-free female Sprague-Dawley rats were randomly allocated to a surgical group,sham surgical group,or control group.A rat model of CC was established by partial ligation of the bile duct.The reliability of the model was confirmed by measurements of serum biochemical indices,morpho-logy of common bile ducts of the rats as well as molecular biology experiments in rat and human tissues.RESULTS Dilation classified as mild(diameter,≥1 mm to<3 mm),moderate(≥3 mm to<10 mm),and severe(≥10 mm)was observed in 17,17,and 2 rats in the surgical group,respectively,while no dilation was observed in the control and sham surgical groups.Serum levels of alanine aminotransferase,aspartate aminotrans-ferase,total bilirubin,direct bilirubin,and total bile acids were significantly elevated in the surgical group as compared to the control group 7 d after surgery,while direct bilirubin,total bilirubin,and gamma-glutamyltransferase were further increased 14 d after surgery.Most of the biochemical indices gradually decreased to normal ranges 28 d after surgery.The protein expression trend of signal transducer and activator of transcription 3 in rat model was consistent with the human CC tissues.CONCLUSION The model of partial ligation of the bile duct of juvenile rats could morphologically simulate the cystic or fusiform CC,which may contribute to investigating the pathogenesis of CC.

An X-Ray Burst Associated with FRB 200428 from a Magnetar-asteroid Impact

Fast radio bursts(FRBs)are extragalactic radio transients with millisecond duration and brightness temperature.An FRB-associated X-ray burst(XRB)was recently found to arise from the Galactic magnetar SGR J1935+2154.Following the model of Dai,in which an FRB may originate from a magnetar encountering an asteroid,we focus on explaining the spectrum of the XRB associated with FRB 200428 from SGR J1935+2154.Collisions between asteroidal fragments and the magnetar surface produce a fireball,which further expands relativistically.Due to the velocity difference among some shells in the fireball,internal shocks would form far away from the magnetar,and further emit X-ray emission.We propose that the FRB-associated XRB can be produced by synchrotron emission from the internal shocks,and then constrain the physical parameters by the observed XRB spectrum.

Value of circulating cell-free DNA in diagnosis of hepatocelluar carcinoma

AIM:To investigate the value of combined detection of circulating cell-free DNA(cfDNA),a-fetal protein(AFP) and a L-fucosidase(AFU) for diagnosis of hepatocellular carcinoma(HCC).METHODS:Serum samples from 39 HCC patients and 45 normal controls were collected.Branched DNA(bDNA) was used to detect the level of cfDNA,and a receiver operating characteristic curve was employed to evaluate the diagnostic sensitivity,specificity,accuracy,positive predictive value,negative predictive value,positive likelihood ratio,negative likelihood ratio and Youden index,and to assess the diagnostic efficiency and their correlations with the clinicopathological features.AFP and AFU were detected by chemiluminescence and colorimetry,respectively.The significance of combined detection of the three biomarkers was discussed.RESULTS:cfDNA level was increased in 22 of the 39 HCC samples and in 2 of the 45 normal controls.cfDNA level in HCC samples was significantly higher than that in normal controls(P < 0.05).There were significant differences in sex and extra-and intrahepatic metastasis(P < 0.05).There was no significant correlation between cfDNA,AFP and AFU in the detection of HCC.The sensitivity of combined detection of cfDNA with one marker(AFP or AFU) and cfDNA with two markers(AFP and AFU) was 71.8%,87.2% and 89.7% vs 56.4%,53.8% and 66.7% for cfDNA,AFP and AFU used alone,respectively,the difference being statistically significant(P < 0.05).CONCLUSION:Quantitative analysis of cfDNA is sensitive and feasible,and the combined detection of cfDNA with AFP or AFU or both could improve the diagnostic sensitivity for HCC.

Cell-permeable Tat-NBD peptide attenuates rat pancreatitis and acinus cell inflammation response

AIM: To investigate the effects of Tat-NEMO-binding domain (NBD) peptide on taurocholate-induced pancreatitis and lipopolysaccharide (LPS)-stimulated AR42J acinus cells inflammatory response in rats. METHODS: Sodium taurocholate (5%) was used to induce the pancreatitis model. Forty-eight rats from the taurocholate group received an intravenous bolus of 13 mg/kg Tat-NBD (wild-type, WT) peptide, TatNBD (mutant-type, MT) peptide, NBD peptide or Tat peptide. The pancreatic histopathology was analyzed by hematoxylin staining. LPS was added to the culture medium to stimulate the AR42J cells. For pretreatment, cells were incubated with different peptides for 2 h before LPS stimulation. Expression of IL-1β and TNF-α mRNA was analyzed using a semi-quantitative reverse-transcript polymerase chain reaction (RT-PCR) method. IL-1β and TNF-α protein in culture medium were detected by enzyme linked immunosorbent assay (ELISA). NF-κB DNA-binding in pancreas was examined by electrophoretic mobility shift assays. P65 expression of AR42J was determined by Strept Actividin-Biotin Complex (SABC) method. RESULTS: Pretreatment with Tat-NBD (WT) peptide at a concentration of 13 mg/kg body wt showed beneficial effect in pancreaitis model. LPS (10 mg/L) resulted in an increase of IL-1β mRNA, IL-1β protein, TNF-α mRNA and TNF-α protein, whereas signifi cantly inhibitory effects were observed when cells were incubated with Tat-NBD (WT). Consisting with p65 expression decrease analyzed by SABC method, NF-κB DNA-binding activity significantly decreased in Tat-NBD (WT) pretreatment group, especially at the largest dose. No significant changes were found in the control peptide group. CONCLUSION: Our result supports that active NF-κB participates in the pathogenesis of STC-induced acute pancreatitis in rats. Tat-NBD (WT) peptide has anti-inflammatory effects in this model and inhibits the inflammation of acinus simulated by LPS.

Stability and control of dynamic walking for a five-link planar biped robot with feet

在两足动物机器人的动态走期间，在旋转激活下面，自由度(DOF ) 出现在支持英尺和地面之间，它做两足动物模型混血儿和尺寸变体。这篇论文为 dimension-varianthybrid 系统(DVHS ) 探讨 asymptotic 轨道稳定性。基于概括 Poincare 地图，为 DVHS 的稳定性标准也是介绍，并且结果然后被用来学习的动态走有脚的一个五连接的平面两足动物机器人。时间不变的步法为与扁平的脚的动态走计划和非线性的控制策略也被介绍。模拟结果显示动态走的一个 asymptotically 稳定的限制周期被建议方法完成。

Rotor Optimization for Synchronous Reluctance Motors

Rotor of Synchronous reluctance motor(SynRM)usually has multiple flux barrier structure for the purpose of higher electromagnetic torque and lower torque ripple.Two different strategies are used in this paper for rotor structure optimization and a compromised strategy for fully squeeze the potential of each related parameters is developed.Performance of resulted rotor structure is evaluated to verify the optimization procedure.

Method for Visual Localization of Oil and Gas Wellhead Based on Distance Function of Projected Features

A localization method based on distance function of projected features is presented to solve the accuracy reduction or failure problem due to occlusion and blurring caused by smog, when dealing with vision based localization for target oil and gas wellhead(OGWH). Firstly, the target OGWH is modeled as a cylinder with marker, and a vector with redundant parameter is used to describe its pose. Secondly, the explicit mapping relationship between the pose vector with redundant parameter and projected features is derived. Then, a 2D-point-to-feature distance function is proposed, as well as its derivative. Finally, based on this distance function and its derivative, an algorithm is proposed to estimate the pose of target OGWH directly according to the 2D image information, and the validity of the method is verified by both synthetic data and real image experiments. The results show that this method is able to accomplish the localization in the case of occlusion and blurring, and its anti-noise ability is good especially with noise ratio of less than 70%.