Development and Validation of a Low-Cost and Simple Simulator for Microlaryngeal Surgery

Pengcheng Yu,Jia Luan,Xidong Cui,Xumao Li,Xinqi Hu,Guangbin Sun 대한이비인후과학회 2020 Clinical and Experimental Otorhinolaryngology Vol.13 No.1

Objectives. The simulation of microlaryngeal skills is rarely seen in surgical training, but it is particularly important in phonomicrosurgery. This study described and validated the laryngeal surgical simulator through surgical training. Methods. A simple and low-cost simulator was developed for the fixation of the suspension laryngoscope and porcine larynges. Twenty participants with work skills and experience did preparation before training, and performed suture and carbon dioxide (CO2) laser cordectomy for simulator evaluation. The results were proposed by the aspects of time taken for each procedure, the global rating scale, a procedure-specific assessment, and a post-simulation questionnaire. Results. All participants completed the preparation within 9 minutes and reached the conclusion that the microlaryngeal surgical simulator was helpful in improving their surgical skills. The performance of experts was superior to that of novices in both suture and CO2 laser cordectomy. Conclusion. This simulator could be easily assembled and was successfully validated by microlaryngeal surgical training both subjectively and objectively. It may be helpful to clinicians in microlaryngeal skills.

Trajectory Synthesis and Optimization of an Underactuated Microrobotic System with Dynamic Constraints and Couplings

Pengcheng Liu,Hongnian Yu,Shuang Cang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5

Motivated by the desire to optimally control the friction-induced stick-slip locomotion and sufficiently improve the energy efficacy, a novel trajectory synthesis and optimization scheme is proposed in this paper for a underactuated microrobotic system with dynamic constraints and couplings. The nonlinear microrobotic model utilizes combined tangential-wise and normal-wise vibrations for underactuated locomotion, which features a generic significance for the studies on microrobotic systems. Specifically, an analytical two-stage velocity trajectory is constructed under control indexes and physical constraints. Subsequently, the dynamic coupling behavior and the qualitative variation laws are characterized through rigorous bifurcation analysis. The synthesized trajectory is optimized and tuned via rigorous analysis based on the robot dynamics. The proposed trajectory planning mechanism provides a promising approach in determining the optimal viscoelastic parameters and trajectory parameters such that the optimal locomotion indexes can be met. Simulation results are presented to demonstrate the efficacy and feasibility of the proposed scheme.

Erdheim-Chester Disease with Emperipolesis: A Unique Case Involving the Heart

Pengcheng Zhu,Naping Li,Lu Yu,Mariajose Navia Miranda,Guoping Wang,Yaqi Duan 대한암학회 2017 Cancer Research and Treatment Vol.49 No.2

Histiocytosis is an uncommon disease characterized by excessive accumulation of histiocytes. Here, we report a rare case of non-Langerhans-cell histiocytosis in a 51- year-old woman who presented with severe symptoms of pericardial effusion. Radiologic investigation also detected multiple bone (lower limbs, vertebrae, ribs, and ilium) lesions. Resected pericardium showed abundant mono- or multi-nucleated non-foamy histiocytes (CD68+/CD163+/S-100+/CD1/langerin) in a fibroinflammatory background. The histiocytes demonstrated emperipolesis of lymphocytes, a hallmark feature of Rosai-Dorfman disease (RDD). However, molecular analysis revealed a BRAF V600E mutation of the proliferating histiocytes, highlighting the neoplastic features frequently observed in another non-Langerhans-cell histiocytosis known as Erdheim- Chester Disease (ECD). We consider this case to be a unique presentation of ECD harboring some RDD-like cells with emperipolesis, but not a case of RDD with a BRAF mutation concerning its clinical manifestation (involvement of the heart and bones) and neoplastic features.

DC-Link Capacitor Voltage Balanced Modulation Strategy Based on Three-Level Neutral-Point-Clamped Cascaded Rectifiers

Pengcheng Han,Xiaoqiong He,Zhiqin Zhao,Haolun Yu,Yi Wang,Xu Peng,Zeliang Shu 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

This study proposes a new modulation strategy to deal with unbalanced output voltage that is based on three-levelneutral-point-clamped cascaded rectifiers. The fundament idea is to reallocate the value of the voltage levels generated by each ofthe modules on the basis of space vector pulse width modulation. This proposed modulation strategy can reduce the switchingfrequency while maintaining the mutual-module voltage balance. First, an analysis of unbalanced output voltage is reflected. Then a new modulation strategy is introduced in detail. Internal module capacitor voltages are balanced by the selection ofredundant vectors. Moreover, the voltage balance ability is calculated. Finally, the feasibility of this modulation strategy isverified through experimental results.

Micro-/Nanocombined Gas Sensors With Functionalized Mesoporous Thin Film Self-Assembled in Batches Onto Resonant Cantilevers

Haitao Yu,Pengcheng Xu,Xiaoyuan Xia,Dong-Weon Lee,Xinxin Li IEEE 2012 IEEE transactions on industrial electronics Vol.59 No.12

<P>This paper reports a novel top-down/bottom-up combined resonant microcantilever chemical sensor, where the nanosensing material of a functionalized mesoporous thin film (MTF) is directly self-assembled on the sensing region of the integrated microcantilever. By using the batch-producible nano-on-micro construction technique, a large number of such sensors can be batch fabricated with uniform performance and low cost. More importantly, the sensing molecule terminals can be simultaneously constructed at the pore inner surface when the MTF is directly grown on the cantilever. With -NH<SUB>2</SUB>-group-functionalized MTF directly grown onto the surface of the cantilever free end, the micro-/nanocombined gravimetric sensor has experimentally exhibited quick response and highly sensitive detection of CO<SUB>2</SUB> gas.</P>

Code development on steady-state thermal-hydraulic for small modular natural circulation lead-based fast reactor

Zhao, Pengcheng,Liu, Zijing,Yu, Tao,Xie, Jinsen,Chen, Zhenping,Shen, Chong Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.12

Small Modular Reactors (SMRs) are attracting wide attention due to their outstanding performance, extensive studies have been carried out for lead-based fast reactors (LFRs) that cooled with Lead or Lead-bismuth (LBE), and small modular natural circulation LFR is one of the promising candidates for SMRs and LFRs development. One of the challenges for the design small modular natural circulation LFR is to master the natural circulation thermal-hydraulic performance in the reactor primary circuit, while the natural circulation characteristics is a coupled thermal-hydraulic problem of the core thermal power, the primary loop layout and the operating state of secondary cooling system etc. Thus, accurate predicting the natural circulation LFRs thermal-hydraulic features are highly required for conducting reactor operating condition evaluate and Thermal hydraulic design optimization. In this study, a thermal-hydraulic analysis code is developed for small modular natural circulation LFRs, which is based on several mathematical models for natural circulation originally. A small modular natural circulation LBE cooled fast reactor named URANUS developed by Korea is chosen to assess the code's capability. Comparisons are performed to demonstrate the accuracy of the code by the calculation results of MARS, and the key thermal-hydraulic parameters agree fairly well with the MARS ones. As a typical application case, steady-state analyses were conducted to have an assessment of thermal-hydraulic behavior under nominal condition, and several parameters affecting natural circulation were evaluated. What's more, two characteristics parameters that used to analyze natural circulation LFRs natural circulation capacity were established. The analyses show that the core thermal power, thermal center difference and flow resistance is the main factors affecting the reactor natural circulation. Improving the core thermal power, increasing the thermal center difference and decreasing the flow resistance can significantly increase the reactor mass flow rate. Characteristics parameters can be used to quickly evaluate the natural circulation capacity of natural circulation LFR under normal operating conditions.

Self-assembly and sensing-group graft of pre-modified CNTs on resonant micro-cantilevers for specific detection of volatile organic compound vapors

Xu, Pengcheng,Li, Xinxin,Yu, Haitao,Liu, Min,Li, Jungang IOP 2010 JOURNAL OF MICROMECHANICS AND MICROENGINEERING - Vol.20 No.11

<P>This paper reports MWCNT (multi-wall carbon nano-tube)-modified resonant micro-cantilever chemical sensors for detection of trinitrotoluene (TNT) vapor. The MWCNTs are pre-modified and then area-selectively self-assembled at the free-end gold pad of a micro-cantilever, in which a resonance-exciting heater and a signal-readout piezoresistive Wheatstone bridge are integrated. Featuring a high specific surface area, the MWCNTs are further functionalized with TNT-sensitive groups by grafting onto the sidewalls of the MWCNTs. To lower the non-specific absorption of water and other small organic molecules, the SiO<SUB>2</SUB> surface of the micro-cantilever was also pre-treated for hydrophobicity and oleophobicity by self-assembling a monolayer of heptadecafluorodecyltrimethoxysilane. The results of our sensing experiments have shown a capability to rapidly detect ppb-level TNT vapor, and a high specificity of the functionalized groups to TNT molecules. The experiment has also confirmed a good long-term stability in detecting sensitivity.</P>

Lactobacillus delbrueckii ssp. lactis R4 Prevents Salmonella typhimurium SL1344-Induced Damage to Tight Junctions and Adherens Junctions

Qinghua Yu,Liqi Zhu,Zhisheng Wang,Pengcheng Li,Qian Yang 한국미생물학회 2012 The journal of microbiology Vol.50 No.4

Cell junctions are the gatekeepers of the paracellular route and defend the mucosal barrier. Several enteropathogenic bacteria can invade intestinal epithelial cells by targeting and damaging cell junctions. It is not well understood how Salmonella typhimurium is able to overcome the intestinal barrier and gain access to the circulation, nor is it understood how Lactobacillus prevents the invasion of S. typhimurium. Therefore, we sought to determine whether infection with S. typhimurium SL1344 could regulate the molecular composition of cell junctions and whether Lactobacillus delbrueckii ssp. lactis R4 could affect this modification. Our data demonstrated that infection of Caco-2 cells with S. typhimurium over 2 h resulted in a redistribution of claudin-1, ZO-1, occluding,and E-cadherin. Western blot analysis of epithelial cell lysates demonstrated that S. typhimurium could decrease the expression of cell junction proteins. However, L. delbrueckii ssp. lactis R4 ameliorated this destruction and induced increased expression of ZO-1, occludin, and E-cadherin relative to the levels in the control group. The results of these experiments implied that S. typhimurium may facilitate its uptake and distribution within the host by regulating the molecular composition of cell junctions. Furthermore,Lactobacillus may prevent the adhesion and invasion of pathogenic bacteria by maintaining cell junctions and the mucosal barrier.

DC-Link Capacitor Voltage Balanced Modulation Strategy Based on Three-Level Neutral-Point-Clamped Cascaded Rectifiers

Han, Pengcheng,He, Xiaoqiong,Zhao, Zhiqin,Yu, Haolun,Wang, Yi,Peng, Xu,Shu, Zeliang The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

This study proposes a new modulation strategy to deal with unbalanced output voltage that is based on three-level neutral-point-clamped cascaded rectifiers. The fundament idea is to reallocate the value of the voltage levels generated by each of the modules on the basis of space vector pulse width modulation. This proposed modulation strategy can reduce the switching frequency while maintaining the mutual-module voltage balance. First, an analysis of unbalanced output voltage is reflected. Then a new modulation strategy is introduced in detail. Internal module capacitor voltages are balanced by the selection of redundant vectors. Moreover, the voltage balance ability is calculated. Finally, the feasibility of this modulation strategy is verified through experimental results.

Astragaloside IV reversed the autophagy and oxidative stress induced by the intestinal microbiota of AIS in mice

Nan Xu,Pengcheng Kan,Xiuhua Yao,Ping Yang,Jiwei Wang,Lei Xiang,Yu Zhu 한국미생물학회 2018 The journal of microbiology Vol.56 No.11

Acute ischaemic stroke (AIS) seriously affects patient quality of life. We explored the role of the intestinal microbiota on oxidative stress and autophagy in stroke, and Astragaloside IV (AS-IV) reversed the changes induced by intestinal microbiota. We determined the characteristics of the intestinal microbiota of AIS and transient ischaemic attack (TIA) patients by 16S sequencing and found that the structure and diversity of the intestinal microbiota in patients with AIS and TIA were significantly different from those in healthy subjects. Specifically, the abundance of genus Bifidobacterium, Megamonas, Blautia, Holdemanella, and Clostridium, content of homocysteine and triglyceride was increased significantly, thus it may be as a potential mechanism of AIS and TIA. Furthermore, germ-free mice were infused intracolonically with fecal supernatants of TIA and AIS with/without feed AS-IV for 12 weeks, and we found that the feces of AIS up-regulated the autophagy markers Beclin-1, light chain 3 (LC3)-II and autophagy-related gene (Atg)12, and the expression of reactive oxygen species (ROS) and NADPH oxidase 2/4 (NOX2/4), malondialdehyde (MDA), however, the expression of total antioxidant capacity (T-AOC) and activity of superoxide dismutase (SOD) and glutathione (GSH) was down-regulated in brain tissue, the content of homocysteine and free fatty acids (FFA) in serum of the mice. Meanwhile, AS-IV could reverse the above phenomenon, however, it does not affect the motor function of mice. AS-IV reversed these changes and it may be a potential drug for AIS therapeutics.