Cardiac-derived stem cell engineered with constitutively active HIF-1a gene enhances blood perfusion of hindlimb ischemia

Xing Pei,Jiyoung Shin,김희정,Nana Wang,Chaewon Seo,Miyun Yoon,Xiongwen Chen,Jianqing Gao,Victor C. Yang,Huining He,Seungjin Lee 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

Stem cell-based therapeutic approach provides a possible treatment for critical limb ischemia (CLI) byinducing revascularization and regenerating ischemic tissue. However, the clinical benefit is modestdue to low cell survival and limited efficacy after transplantation. Cardiac-derived stem cells (CSCs) mightbe a novel cell source for CLI treatment owing to their superb endothelial differentiation potential andangiogenic paracrine functions. In this study, the angiogenic ability of CSCs was maximized by geneticengineering with constitutively active form of hypoxia-inducible factor-1a (CA-HIF-1a), resistant tooxygen-dependent degradation. CSCs transfected with CA-HIF-1a (CA-HIF-CSCs) promoted supplementaryexpression of proangiogenic factors including VEGF, bFGF, Ang-1 and PDGF-B, along with enhancedangiogenic function including migratory effect, tube formation and endothelial differentiation potential. In the mouse CLI model, CA-HIF-CSCs transplanted into the ischemic region using fibrin gel as cell deliveryvehicle, improved blood perfusion and limb functional recovery with minimal incidence of foot necrosisand limb loss by promoting new vessel formation. Histological evidence further confirmed that CAHIF-CSC/gel treatment markedly alleviated muscle degeneration and fibrosis. CSCs genetically engineeredwith constitutively active HIF-1a provide a novel therapeutic modality in CLI combining stem cell andgene therapy.

Effects of Oxygen Content on the Simultaneous Microbial Removal of SO2 and NOx in Biotrickling Towers

Xing Chun Wang,Xiao Yi Bi,Pei Shi Sun,Jin Quan Chen,Ping Zou,Xiao Ming Ma,Jing Zhang,Hai Yu Wang,Xiao Yi Xu 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.5

This study uses microbial methods to research the influence of oxygen (O2) content on the removal efficiency of sulfur dioxide (SO2) and nitrogen oxides (NOx) in a tandem twin-towers desulfurization and denitrification process system. Oxygen can play a significant role in biotrickling towers. Other important factors had already been optimized prior to the study, including inlet concentration, gas flow rate, and temperature. SO2 and NOx were prepared by a chemical method. A gas flow meter was used to regulate nitrogen (N2) that had been stored in steel cylinders. In this way, the O2 content was adjusted in the biotrickling towers by controlling the N2 flow rate. Five gradients of O2 content were selected for investigation, namely 4, 8, 12, 16, and 20%. Results indicated that the SO2 removal efficiency from mixed gas (SO2 and NOx) can reach 100%, from all of the five O2 gradients, in biotrickling towers. In a tandem twin-towers desulfurization and denitrification process system, the NOx removal efficiency and the inlet concentration of nitrogen dioxide (NO2) gradually increased as the O2 content increased. Specifically, the average removal efficiency of NOx increased from 49.28 to 80.85% as the O2 content changed from 4 to 20%. The oxygen levels influenced the removal of NOx but the SO2 removal efficiency in mixed gas was always stable.

Optical Design of an Off-axis Five-mirror-anastigmatic Telescope for Near Infrared Remote Sensing

Xing long Li,Min Xu,Yun tian Pei 한국광학회 2012 Current Optics and Photonics Vol.16 No.4

This paper described an off-axis five-mirror-anastigmatic telescope. It is composed of three aspheric surfaces and one spherical surface while the third mirror and fifth mirror have the same parameters at the same place. This configuration is useful for having wide field of view. The strip full field of view for the near infrared telescope is 20°×0.2°. The entrance pupil is located in front of the first mirror. There is an intermediate image between the second mirror and the third mirror. The entrance pupil diameter is 100 mm and the effective focal length is 250 mm. The spectral range is 0.85 -1.75 μm. The pixel pitch is 15 μm. The image quality is near the diffraction limit. Some methods were used to restrain the stray light such as a field stop near the intermediate image, the baffle, the narrow-band pass filter and a stop in front of the focal plane.

Shear behavior of multi-hole perfobond connectors in steel-concrete structure

Xing Wei,Lin Xiao,Shiling Pei 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.56 No.6

This study focuses on the load carrying capacity and the force transfer mechanism of multi-hole perfobond shear connectors in steel-concrete composite structure. The behavior of multi-hole perfobond shear connector is more complicated than single-hole connector cases. 2 groups push-out tests were conducted. Based on the test results, behavior of the connection was analyzed and the failure mechanism was identified. Simplified iterative method and analytic solution were proposed based on force equilibrium for analyzing multi-hole perfobond shear connector performance. Finally, the sensitivity of design parameters of multi-hole perfobond shear connector was investigated. The results of this research showed that shear force distribution curve of multi-hole perfobond shear connector is near catenary. Shear forces distribution were determined by stiffness ratio of steel to concrete member, stiffness ratio of shear connector to steel member, and number of row. Efficiency coefficient was proposed to should be taking into account in different limit state.

Servo control strategy for uni-axial shake tables using long short-term memory networks

Pei-Ching Chen,Kui-Xing Lai 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.32 No.6

Servo-motor driven uniaxial shake tables have been widely used for education and research purposes in earthquake engineering. These shake tables are mostly displacement-controlled by a digital proportional-integral-derivative (PID) controller; however, accurate reproduction of acceleration time histories is not guaranteed. In this study, a control strategy is proposed and verified for uniaxial shake tables driven by a servo-motor. This strategy incorporates a deep-learning algorithm named Long Short-Term Memory (LSTM) network into a displacement PID feedback controller. The LSTM controller is trained by using a large number of experimental data of a self-made servo-motor driven uniaxial shake table. After the training is completed, the LSTM controller is implemented for directly generating the command voltage for the servo motor to drive the shake table. Meanwhile, a displacement PID controller is tuned and implemented close to the LSTM controller to prevent the shake table from permanent drift. The control strategy is named the LSTM-PID control scheme. Experimental results demonstrate that the proposed LSTM-PID improves the acceleration tracking performance of the uniaxial shake table for both bare condition and loaded condition with a slender specimen.

Distribution of shear force in perforated shear connectors

Xing Wei,M. Shariati,Y. Zandi,Shiling Pei,Zhibin Jin,S. Gharachurlu,M.M. Abdullahi,M.M. Tahir,M. Khorami 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.27 No.3

A perforated shear connector group is commonly used to transfer shear in steel–concrete composite structures when the traditional shear stud connection is not strong enough. The multi-hole perforated shear connector demonstrates a more complicated behavior than the single connector. The internal force distribution in a specific multi-hole perforated shear connector group has not been thoroughly studied. This study focuses on the load-carrying capacity and shear force distribution of multi-hole perforated shear connectors in steel.concrete composite structures. ANSYS is used to develop a three-dimensional finite element model to simulate the behavior of multi-hole perforated connectors. Material and geometric nonlinearities are considered in the model to identify the failure modes, ultimate strength, and load–slip behavior of the connection. A three-layer model is introduced and a closed-form solution for the shear force distribution is developed to facilitate design calculations. The shear force distribution curve of the multi-hole shear connector is catenary, and the efficiency coefficient must be considered in different limit states.

Experiment Study on Fatigue Performance of Perforated Shear Connectors

Xing Wei,Lin Xiao,Shiling Pei 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.3

In order to investigate the fatigue behavior of perforated shear connection in steel-concrete composite bridges, 24 connection specimens with different geometric configurations were subjected to static and fatigue testing protocols. Using the design shear resistance of perforated shear connectors obtained from static push-out tests as a reference load level, numbers of fatigue cycles under different cyclic load levels were determined. Accumulated relative slip between steel and concrete components was used to characterize and track fatigue damage accumulation. The relationship between cycle numbers and accumulated relative slip between steel and concrete was established. Test results revealed that the fatigue damage of perforated shear connectors can be divided into three stages, and fatigue life of perforated shear connectors can be evaluated by the accumulated slip, which depends on the maximum shear stress and stress range.

An Optical Design of Off-axis Four-mirror-anastigmatic Telescope for Remote Sensing

Xing long Li,Min Xu,Xian dong Ren,Yun tian Pei 한국광학회 2012 Current Optics and Photonics Vol.16 No.3

An off-axis four-mirror-anastigmatic telescope is presented here which is composed of two aspheric surfaces and two spherical surfaces. The entrance pupil diameter is 290 mm and the stop is located at the primary mirror. The effective focal length is 900 mm. The strip field of view for the telescope is 15° × 0.2° and if the telescope is launched into an orbit about 400 km altitude, the observed range width will be more than 105 km within a scene without any other auxiliary scanning instrument. The spectral range can be as wide as from visual wave band to infrared wave band in the mirror system. This telescope can be used for environmental monitoring with different detectors whose pixel is adapted to the optical resolution. In this paper, the spectral range is chosen as 3.0 -5.0 μm, and center distance of the pixel is 30 μm. And the image quality is near the diffraction limit.

Applying the OMOP Common Data Model to Facilitate Benefit-Risk Assessments of Medicinal Products Using Real-World Data from Singapore and South Korea

Hui Xing Tan,Desmond Chun Hwee Teo,이동윤,김청수,Jing Wei Neo,Cynthia Sung,Haroun Chahed,Pei San Ang,Doreen Su Yin Tan,박래웅,Sreemanee Raaj Dorajoo 대한의료정보학회 2022 Healthcare Informatics Research Vol.28 No.2

Objectives: The aim of this study was to characterize the benefits of converting Electronic Medical Records (EMRs) to acommon data model (CDM) and to assess the potential of CDM-converted data to rapidly generate insights for benefitriskassessments in post-market regulatory evaluation and decisions. Methods: EMRs from January 2013 to December 2016were mapped onto the Observational Medical Outcomes Partnership-CDM (OMOP-CDM) schema. Vocabulary mappingswere applied to convert source data values into OMOP-CDM-endorsed terminologies. Existing analytic codes used in a priorOMOP-CDM drug utilization study were modified to conduct an illustrative analysis of oral anticoagulants used for atrialfibrillation in Singapore and South Korea, resembling a typical benefit-risk assessment. A novel visualization is proposed torepresent the comparative effectiveness, safety and utilization of the drugs. Results: Over 90% of records were mapped ontothe OMOP-CDM. The CDM data structures and analytic code templates simplified the querying of data for the analysis. Intotal, 2,419 patients from Singapore and South Korea fulfilled the study criteria, the majority of whom were warfarin users. After 3 months of follow-up, differences in cumulative incidence of bleeding and thromboembolic events were observable viathe proposed visualization, surfacing insights as to the agent of preference in a given clinical setting, which may meaningfullyinform regulatory decision-making. Conclusions: While the structure of the OMOP-CDM and its accessory tools facilitatereal-world data analysis, extending them to fulfil regulatory analytic purposes in the post-market setting, such as benefit-riskassessments, may require layering on additional analytic tools and visualization techniques.

Generator Bearing Fault Diagnosis Based on Analytic Hierarchy Process and Binary-tree Support Vector Machine

ZHANG Xing-yuan,CHEN Minye,XU Hai-rong,LI Pei-qi 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.8

Binary-tree support vector machine (SVM) has such advantages as small repeated operation workload, fast classification speed and dead zone inexistence, but the structural design can influence the classification accuracy thereof. In order to rationally design the structure of the binary-tress SVM, a multi-classification algorithm (AHP-BSVM) combining analytic hierarchy process (AHP) and binary-tree SVM is proposed in this paper. Firstly, the analytic hierarchy process is adopted to establish the evaluation system model so as to comprehensively evaluate multiple influencing factors for determining the weight values of various faults; then, the faults are ordered by the weight values and the structure of the binary-tree SVM is determined according to the fault sequence; finally, the proposed algorithm is adopted for fault diagnosis and analysis. The simulation experiment shows: compared with other algorithms, the proposed algorithm has higher recognition accuracy and higher classification accuracy, and is applicable to multi-classification, thus having good promotion prospect.