A mechanics-based model for predicting flexible needle bending with large curvature in soft tissue.

Percutaneous insertion is one of the most common minimally invasive procedures. Compared with traditional straight rigid needles, bevel-tipped flexible needle can generate curved trajectories to avoid obstacles and sensitive organs. However, the nonlinear large deflection problem challenges the bending prediction of the needle, which dramatically influences the surgical success rate. This paper analyzed the mechanism of needle-tissue interaction, and established a mechanics-based model of the needle bending during an insertion. And then, a discretization of the bending model was adopted to accurately predict the large bending of the needle in soft tissue. Insertion experiments were conducted to validate the bending prediction model. The results showed that the large needle bending was predicted with the mean/RMSE/maximumu error of 0.42 mm / 0.26 mm / 1.08 mm, which was clinically acceptable. This proved the rationality and accuracy of the proposed model.

Metabolic disorder of fatty acids and bile acids caused by organochlorine pesticides:research progress / 中国药理学与毒理学杂志

Organochlorine pesticides(OCP)exist widely in the environment,which may threaten human health and cumulate for years once absorbed in the body.OCP metabolites in the body are associated with metabolic disorders.In vivo and in vitro exposure of OCP could enhance hepatic fatty acid synthesis, and interfere in the β-oxidation of fatty acids by impairing the function and structure of mitochondria in hepatocytes. Moreover, OCP can increase secondary bile acid formation by modulating of gut microbiota and reduceing ileal bile acid re-absorption,resulting in compensatory increase of hepatic bile acid synthesis. This review summarizes the mechanism of fatty acid and bile acid metabolic abnormalities caused by OCP.

Development of a coordinated controller for robot-assisted shape memory alloy actuated needle for prostate brachytherapy.

This paper deals with the development of a coordinated control system for a robot and robot-driven shape memory alloy (SMA) actuated needle to follow a curvilinear path for percutaneous intervention. The robot driving the needle is considered as the outer loop and the non-linear SMA actuated flexible needle system forms the inner loop. The two feedback control loops are coordinated in such a way that the robot drives the needle considering the needle's actual deflection so that the needle tip reaches the target location with an acceptable accuracy. Simulation results are presented to verify the efficacy of the controller for tracking the overall desired trajectory which includes the combined trajectory of the robot and the needle.

Path planning for robot-assisted active flexible needle using improved Rapidly-Exploring Random trees.

In robot-assisted needle-based medical procedures, path planning for a flexible needle is challenging with regard to time consumption and searching robustness for the solution due to the nonholonomic motion of the needle tip and the presence of anatomic obstacles and sensitive organs in the intended needle path. We propose a novel and fast path planning algorithm for a robot-assisted active flexible needle. The algorithm is based on Rapidly-Exploring Random Trees combined with reachability-guided strategy and greedy heuristic strategy. Linear segments are taken into consideration to the paths, and insertion orientations are relaxed by the introduction of the linear segments. The proposed algorithm yields superior results as compared to the commonly used algorithm in terms of computational speed, form of path and robustness of searching ability, which potentially can make it suitable for the real-time intraoperative planning for clinical procedures.

Study on the characteristics of inheritance and epidemiology in one pedigree with gallstone disease / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the characteristics of inheritance and epidemiology of gallstone disease in one pedigree.</p><p><b>METHODS</b>A gallbladder disease-specific questionnaire was administered to all family members to ascertain histories of cholecystectomy and other medical conditions as well as anthropometrical data. Laboratory examination and ultrasonography were performed to determine the existence of gallstone.</p><p><b>RESULTS</b>One hundred and thirteen members of four generations in the index family were enrolled in the study. The prevalence of gallstone in females (34.48%) was higher than in males (23.64%) but with no significant difference. The prevalence in the second and third generations (52%) was higher than in others (20%) (P < 0.05). The heritability and standard error showed as 86.38% +/- 46.46% in I generations. Body mass index, histories of hypertension, hyperlipidemia and blood glucose were positively related to gallstone disease (P = 0.012, < 0.01, 0.017, 0.043, respectively) in this family. Gallstone disease was not significantly related to history of diabetes, daily alcohol or diet habit. Plasma cholesterol and triglyceride levels were not correlated with gallstone disease.</p><p><b>CONCLUSION</b>Gallstone disease presented aggregation in the family and was in accordance with the characteristics of autosomal dominant inheritance. Being female, obesity, hypertension and history of hyperlipidemia might serve as risk factors to this family.</p>

Expression of liver receptor homolog 1 gene in patients with cholesterol gallstone disease / 中华消化杂志

Objective To investigate the mRNA expression of liver receptor homolog 1 (LRH-1) gene in patients with cholesterol gallstone disease so that to elucidate the biomolecular pathogenesis of gallstone for- mation.Methods Twenty-seven patients with cholesterol gallstone (CGS) and 14 controls were included in this study.Biliary composition was assayed and mRNA expression of hepatic LRH 1 gene was determined by real time polymorphism chain reaction.Results In CGS patients,expression of LRH-1 was significantly higher than that in controls (14.18?9.37 vs 7.86?6.19,P＜0.05),and cholesterol of bile was oversaturated (1.17?0.27).Conclusion The formation of CGS may be related to increased expression of hepatic LRH-1 gene.