A comparative study to measure the sagittal condylar inclination using mechanical articulator, virtual articulator and jaw tracking device

Liya Ma,Fei Liu,Jiansong Mei,Jiarui Chao,Zhenyu Wang,Jiefei Shen 대한치과보철학회 2023 The Journal of Advanced Prosthodontics Vol.15 No.1

Purpose. To compare the sagittal condylar inclination (SCI) in dentate individuals measured by the different methods with mechanical articulator (MA), virtual articulator (VA), and a jaw tracking device (JTD) system. Materials and methods. A total of 22 healthy dentate participants were enrolled in this study. For MA workflow, the SCI was obtained by a semi-adjustable articulator with protrusive interocclusal records. The SCI was also set on a VA by aligning intraoral scan (IOS) with cone beam computed tomography (CBCT) and facial scan (FS), respectively. These virtual workflows were conducted in a dental design software, namely VAIOS-CBCT and VAIOS-FS. Meanwhile, a JTD system was also utilized to perform the measurement. Intraclass correlation was used to assess the repeatability within workflows. The bilateral SCI values were compared by Wilcoxon matched-pairs signed rank test for each workflow, and Kruskal-Wallis test and post hoc p-value Bonferroni correction were used to compare the differences among four workflows. The agreement of VAIOS-CBCT, VAIOS-FS, and JTD compared with MA was evaluated by Bland-Altman analysis. Results. Intraclass correlation of the SCI revealed a high degree of repeatability for each workflow. There were no significant differences between the left and right sides (P > .05), except for VAIOS-CBCT (P = .028). Significant differences were not found between MA and VAIOS-FS (P > .05). Bland-Altman plots indicated VAIOS-CBCT, VAIOS-FS, and JTD were considered to substitute MA with high 95% limits of agreement. Conclusion. The workflow of VAIOS-FS provided an alternative approach to measure the SCI compared with MA.

CCL12 induces trabecular bone loss by stimulating RANKL production in BMSCs during acute lung injury

Ma Chao,Gao Juan,Liang Jun,Wang Feizhen,Xu Long,Bu Jinhui,He Bo,Liu Guangpu,Niu Ru,Liu Guangwang 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

In the last three years, the capacity of health care systems and the public health policies of governments worldwide were challenged by the spread of SARS-CoV-2. Mortality due to SARS-CoV-2 mainly resulted from the development of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Moreover, millions of people who survived ALI/ARDS in SARS-CoV-2 infection suffer from multiple lung inflammation-induced complications that lead to disability and even death. The lung-bone axis refers to the relationship between lung inflammatory diseases (COPD, asthma, and cystic fibrosis) and bone diseases, including osteopenia/osteoporosis. Compared to chronic lung diseases, the influence of ALI on the skeleton has not been investigated until now. Therefore, we investigated the effect of ALI on bone phenotypes in mice to elucidate the underlying mechanisms. In vivo bone resorption enhancement and trabecular bone loss were observed in LPS-induced ALI mice. Moreover, chemokine (C-C motif) ligand 12 (CCL12) accumulated in the serum and bone marrow. In vivo global ablation of CCL12 or conditional ablation of CCR2 in bone marrow stromal cells (BMSCs) inhibited bone resorption and abrogated trabecular bone loss in ALI mice. Furthermore, we provided evidence that CCL12 promoted bone resorption by stimulating RANKL production in BMSCs, and the CCR2/Jak2/STAT4 axis played an essential role in this process. Our study provides information regarding the pathogenesis of ALI and lays the groundwork for future research to identify new targets to treat lung inflammation-induced bone loss.

Prediction of Venous Trans-Stenotic Pressure Gradient Using Shape Features Derived From Magnetic Resonance Venography in Idiopathic Intracranial Hypertension Patients

Ma Chao,Zhu Haoyu,Liang Shikai,Chang Yuzhou,Mo Dapeng,Jiang Chuhan,Zhang Yupeng 대한영상의학회 2024 Korean Journal of Radiology Vol.25 No.1

Objective: Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology associated with venous sinus stenosis. This study aimed to develop a magnetic resonance venography (MRV)-based radiomics model for predicting a high trans-stenotic pressure gradient (TPG) in IIH patients diagnosed with venous sinus stenosis. Materials and Methods: This retrospective study included 105 IIH patients (median age [interquartile range], 35 years [27– 42 years]; female:male, 82:23) who underwent MRV and catheter venography complemented by venous manometry. Contrast enhanced-MRV was conducted under 1.5 Tesla system, and the images were reconstructed using a standard algorithm. Shape features were derived from MRV images via the PyRadiomics package and selected by utilizing the least absolute shrinkage and selection operator (LASSO) method. A radiomics score for predicting high TPG (≥ 8 mmHg) in IIH patients was formulated using multivariable logistic regression; its discrimination performance was assessed using the area under the receiver operating characteristic curve (AUROC). A nomogram was constructed by incorporating the radiomics scores and clinical features. Results: Data from 105 patients were randomly divided into two distinct datasets for model training (n = 73; 50 and 23 with and without high TPG, respectively) and testing (n = 32; 22 and 10 with and without high TPG, respectively). Three informative shape features were identified in the training datasets: least axis length, sphericity, and maximum three-dimensional diameter. The radiomics score for predicting high TPG in IIH patients demonstrated an AUROC of 0.906 (95% confidence interval, 0.836– 0.976) in the training dataset and 0.877 (95% confidence interval, 0.755–0.999) in the test dataset. The nomogram showed good calibration. Conclusion: Our study presents the feasibility of a novel model for predicting high TPG in IIH patients using radiomics analysis of noninvasive MRV-based shape features. This information may aid clinicians in identifying patients who may benefit from stenting.

Robust Stability Analysis of Time-varying Delay Systems via an Augmented States Approach

Chao-Yang Dong,Ming-Yu Ma,Qing Wang,Si-Qian Ma 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

This paper focuses on the robust stability analysis of linear systems with time varying delays. The second derivative of the state is used to construct a novel Lyapunov-Krasovskii functional (LKF). Then, both the integrals and derivatives of the states along with the delayed states could be taken into consideration in handling of the LKF. We introduce these augmented variables and establish correlations between them. Moreover, our approach makes it available that quadratic convex combination can be applied not only to the time delay, but also to the derivative of it. Robust stability criteria are presented, and numerical examples illustrate that the methods are less conservative.

Radian of the vault influencing the seismic performances of straight wall arch underground structures

Chao Ma,Dechun Lu,Chengzhi Qi,Xiuli Du 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.5

Great efforts have been conducted to investigate the seismic performances of the arch and rectangular underground structures, however, the differences between seismic responses of these two types of underground structures, especially the vault radian influencing the seismic responses of arch structures are not clarified. This paper presents a detailed numerical investigation on the seismic responses of arch underground structures with different vault radians, and aims to illustrate the rule that vault radian affects the seismic responses of underground structures. Five arch underground structures are built for nonlinear soil-structure interaction analysis. The internal forces of the structural components of the underground structures only under gravity are discussed detailedly, and an optimum vault radian for perfect load-carrying functionality of arch underground structures is suggested. Then the structures are analyzed under seven scaled ground motions, amounting to a total of 35 dynamic calculations. The numerical results show that the vault radian can have beneficial effects on the seismic response of the arch structure, compared to the rectangular underground structures, causing the central columns to suffer smaller axial force and horizontal deformation. The conclusions provide some directive suggestions for the seismic design of the arch underground structures.

Force identification technique by the homotopy method

Ma Chao,Hua Hongxing 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

Force identification problem is a well-known ill-posed problem because of the inversion process involved and the noise included in themeasured data. In this paper, a homotopy method based on L-curve criterion is proposed to deal with this issue. The validity of themethod is illustrated by both the linear and nonlinear systems in the numerical examples. Moreover, the accuracy and efficiency of theproposed method are compared with those of the traditional one and Tikhonov technique by L-curve criterion. Results show that theproposed method gives more reliable results than the other two methods.

The Forecasting of Weekly Tourists Visiting a Scenic Area in Off-Season by Using Goodness of Fit Weight

Ma Yin-chao,Liang Chang-yong,Lu Cai-hong 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.3

REGENERATIVE BRAKING CONTROL STRATEGY BASED ON MULTI-SOURCE INFORMATION FUSION UNDER ENVIRONMENT PERCEPTION

Chao Ma 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.3

In this paper, regenerative braking control of electric vehicles is investigated based on multi-source information such as image recognition, GPS and vehicle running parameters. Firstly, the fast normalized cross-correlation (FNCC) algorithm is applied to identify the speed limit traffic signs. Then the vehicle speed is intelligently controlled under the fusion of the detected traffic signs and road slope prediction information. Secondly, an adaptive regenerative braking energy recovery strategy based on multi-source information fusion is designed. The adaptive control strategy can automatically adjust under different braking conditions, so the motor can work at the high-efficiency points. The adaptive control strategy provides the possibility to realize the efficient recovery of braking energy. Finally, the effectiveness of the strategy is verified by MATLAB/ Simulink and Prescan co-simulation. Specially, a regenerative braking proportional coefficient K under the multi-source information fusion is proposed. The K can optimize the braking torque distribution and improve the motor high-efficiency operating range. Compared with the traditional series control strategy and fuzzy control strategy, the adaptive control strategy improves the energy recovery rate by 11.9 % and 5.3 % respectively.

Development of Control Strategy and Energy Management for Plug-in HEV

Chao Ma,Jian Ji(지건),Hyunsoo Kim(김현수) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

Plug-in Hybrid Electric Vehicle (PHEV) is considered as the next design objective of hybrid electric vehicle (HEV). It combines the advantages of electric vehicle (EV) and HEV. PHEV has full electric drive mode which can be applied in relative short distance and HEV mode which can be used for long distance. In this paper, the powertrain model of the PHEV is obtained. Based on the analysis of the powertrain model, the control strategy and energy management strategy of PHEV are developed. The PHEV simulator is constructed MATLAB/Simulink. Using the powertrain model and the control strategies, simulations are performed and the simulation results are analyzed. Finally, the plug-in Prius simulator is validated by using the PSAT. It is expected that the PHEV performance can be used for the designers to develop a PHEV.

A meso-scale approach to modeling thermal cracking of concrete induced by water-cooling pipes

Chao Zhang,Wei Zhou,Gang Ma,Chao Hu,Shaolin Li 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.15 No.4

Cooling by the flow of water through an embedded cooling pipe has become a common and effective artificial thermal control measure for massive concrete structures. However, an extreme thermal gradient induces significant thermal stress, resulting in thermal cracking. Using a mesoscopic finite-element (FE) mesh, three-phase composites of concrete namely aggregate, mortar matrix and interfacial transition zone (ITZ) are modeled. An equivalent probabilistic model is presented for failure study of concrete by assuming that the material properties conform to the Weibull distribution law. Meanwhile, the correlation coefficient introduced by the statistical method is incorporated into the Weibull distribution formula. Subsequently, a series of numerical analyses are used for investigating the influence of the correlation coefficient on tensile strength and the failure process of concrete based on the equivalent probabilistic model. Finally, as an engineering application, damage and failure behavior of concrete cracks induced by a water-cooling pipe are analyzed in-depth by the presented model. Results show that the random distribution of concrete mechanical parameters and the temperature gradient near water-cooling pipe have a significant influence on the pattern and failure progress of temperature-induced micro-cracking in concrete.