Simulation and Experiment Analysis of Driveshaft

A driveshaft is a small spring coil less than 1mm in diameter, composed of several stainless-steel wire filaments. In intervention, the driveshaft is used to transmit force and motion to the inside body through the existing micro channels (such as arteries, veins, and gastrointestinal tract). The performance of the driveshaft determines the efficiency, stability, and accuracy of force and motion transitions, the ability to pass through tortuous microchannels, and the damage to healthy tissues. To determine the influence of fabrication parameters (filament, wire diameter, and outer diameter) on the mechanical properties (such as bending stiffness and natural frequency) of the driveshaft, a simulation was established in ABAQUS to calculate the deformation displacement under 0.0098N and first-order natural frequency. Then, the bending stiffness is calculated. The results show that the bending stiffness and the first-order natural frequency of the driveshaft increase with the increase of the filament number and wire diameter, and with the outer diameter of the driveshaft increases, the bending stiffness increases, while the first-order natural frequency decreases. Finally, the simulation model is verified by measuring the deformation displacement in the experiment. This study provides a methodology for designing and selecting the driveshaft in Interventional therapy

Recent advances in optical aptasensors for biomarkers in early diagnosis and prognosis monitoring of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) accounts for approximately 90% of all primary liver cancers and is one of the main malignant tumor types globally. It is essential to develop rapid, ultrasensitive, and accurate strategies for the diagnosis and surveillance of HCC. In recent years, aptasensors have attracted particular attention owing to their high sensitivity, excellent selectivity, and low production costs. Optical analysis, as a potential analytical tool, offers the advantages of a wide range of targets, rapid response, and simple instrumentation. In this review, recent progress in several types of optical aptasensors for biomarkers in early diagnosis and prognosis monitoring of HCC is summarized. Furthermore, we evaluate the strengths and limitations of these sensors and discuss the challenges and future perspectives for their use in HCC diagnosis and surveillance

Chemical Constituents and Antioxidant Properties of Phyllostachys prominens Gramineae (W Y Xiong ) Leaf Extracts

Purpose: To isolate and identify chemical components of Phyllostachys prominens (Poaceae) leaf extracts, and measure their antioxidant activities.Methods: Ethanol extracts of P. prominens leaves were subjected to different chromatographic methods: macroporous resin column chromatography, Sephadex LH-20 column chromatography, and semi-preparative, reversed-phase (RP) high performance liquid chromatography (HPLC). Plant extract components were identified by ultraviolet spectroscopy (UV), mass spectrometry (MS), and nuclear magnetic resonance spectroscopy (NMR). DPPH (1,1-diphenyl 2-picrylhydrazyl) assay was used to measure the radical scavenging activity of the compounds .Results: We isolated fourteen compounds including six flavonoids, two lignans, two phenolic glycosides, a phenolic acid, a phenylpropanoid, a monoterpene glycoside, and amarusine from the leaves of Phyllostachys prominens. The DPPH assay showed that eleven compounds (compounds 1, 4, 6, 7, 8, 9, 10, 11, 12, 13, and 14) exhibited radical scavenging activity. (The half maximal inhibitory concentration ranged from 33.52 to 100.58 μg/mL). The half maximal inhibitory concentration (IC50) values of compounds 1, 4, 6 and 7 were 33.52, 40.61, 47.10, and 35.84 μg/mL respectively, while the IC50 of the positive control, butylated hydroxytoluene, was 46.32 μg/mL.Conclusion: Fourteen compounds have been successfully all isolated from Phyllostachys prominens for the first time. Eleven of the compounds have radical scavenging activity.Keywords: Phyllostachys prominens, Phytochemicals, Flavonoids, Lignans, Antioxidant activit