MiRNA320a Inhibitor-Loaded PLGA-PLL-PEG Nanoparticles Contribute to Bone Regeneration in Trauma-Induced Osteonecrosis Model of the Femoral Head

Zhang Ying,Li Chuan,Wei Qiushi,Yuan Qiang,He Wei,Zhang Ning,Dong Yiping,Jing Zhenhao,Zhang Leilei,Wang Haibin,Cao Xiangyang 한국조직공학과 재생의학회 2024 조직공학과 재생의학 Vol.21 No.1

BACKGROUND: This study aimed to explore the effect of a nanomaterial-based miR-320a inhibitor sustained release system in trauma-induced osteonecrosis of the femoral head (TIONFH). METHODS: The miR-320a inhibitor-loaded polyethylene glycol (PEG)- Poly(lactic-co-glycolic acid) (PLGA)- Poly-L-lysine (PLL) nanoparticles were constructed using the double emulsion method. The TIONFH rabbit model was established to observe the effects of miR-320a inhibitor nanoparticles in vivo. Hematoxylin–eosin staining and microcomputed tomography scanning were used for bone morphology analysis. Bone marrow mesenchymal stem cells (BMSCs), derived from TIONFH rabbits, were used for in vitro experiments. Cell viability was determined using the MTT assay. RESULTS: High expression of miR-320a inhibited the osteogenic differentiation capacity of BMSCs in vitro by inhibiting the expression of the osteoblastic differentiation markers ALP and RUNX2. MiR-320a inhibitor-loaded PEG-PLGA-PLL nanoparticles were constructed with a mean loading efficiency of 1.414 ± 0.160%, and a mean encapsulation efficiency of 93.45 ± 1.24%, which released 50% of the loaded miR-320a inhibitor at day 12 and 80% on day 18. Then, inhibitor release entered the plateau. After treatment with the miR-320a inhibitor nanoparticle, the empty lacunae were decreased in the femoral head tissue of TIONFH rabbits, and the osteoblast surface/bone surface (Ob.S/BS), osteoblast number/bone perimeter (Ob.N/B.Pm), bone volume fraction, and bone mineral density increased. Additionally, the expression of osteogenic markers RUNX2 and ALP was significantly elevated in the TIONFH rabbit model. CONCLUSION: The miR-320a inhibitor-loaded PEG-PLGA-PLL nanoparticle sustained drug release system significantly contributed to bone regeneration in the TIONFH rabbit model, which might be a promising strategy for the treatment of TIONFH. BACKGROUND: This study aimed to explore the effect of a nanomaterial-based miR-320a inhibitor sustained release system in trauma-induced osteonecrosis of the femoral head (TIONFH). METHODS: The miR-320a inhibitor-loaded polyethylene glycol (PEG)- Poly(lactic-co-glycolic acid) (PLGA)- Poly-L-lysine (PLL) nanoparticles were constructed using the double emulsion method. The TIONFH rabbit model was established to observe the effects of miR-320a inhibitor nanoparticles in vivo. Hematoxylin–eosin staining and microcomputed tomography scanning were used for bone morphology analysis. Bone marrow mesenchymal stem cells (BMSCs), derived from TIONFH rabbits, were used for in vitro experiments. Cell viability was determined using the MTT assay. RESULTS: High expression of miR-320a inhibited the osteogenic differentiation capacity of BMSCs in vitro by inhibiting the expression of the osteoblastic differentiation markers ALP and RUNX2. MiR-320a inhibitor-loaded PEG-PLGA-PLL nanoparticles were constructed with a mean loading efficiency of 1.414 ± 0.160%, and a mean encapsulation efficiency of 93.45 ± 1.24%, which released 50% of the loaded miR-320a inhibitor at day 12 and 80% on day 18. Then, inhibitor release entered the plateau. After treatment with the miR-320a inhibitor nanoparticle, the empty lacunae were decreased in the femoral head tissue of TIONFH rabbits, and the osteoblast surface/bone surface (Ob.S/BS), osteoblast number/bone perimeter (Ob.N/B.Pm), bone volume fraction, and bone mineral density increased. Additionally, the expression of osteogenic markers RUNX2 and ALP was significantly elevated in the TIONFH rabbit model. CONCLUSION: The miR-320a inhibitor-loaded PEG-PLGA-PLL nanoparticle sustained drug release system significantly contributed to bone regeneration in the TIONFH rabbit model, which might be a promising strategy for the treatment of TIONFH.

Evaluation of structural safety reduction due to water penetration into a major structural crack in a large concrete project

Xiangyang Zhang,Vahid Bayat,Mohammadreza Koopialipoor,Danial Jahed Armaghani,Weixun Yong,Jian Zhou 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.3

Structural damage to an arch dam is often of major concern and must be evaluated for probable rehabilitation to ensure safe, regular, normal operation. This evaluation is crucial to prevent any catastrophic or failure consequences for the life time of the dam. If specific major damage such as a large crack occurs to the dam body, the assessments will be necessary to determine the current level of safety and predict the resistance of the structure to various future loading such as earthquakes, etc. This study investigates the behavior of an arch dam cracked due to water pressure. Safety factors (SFs), of shear and compressive tractions were calculated at the surfaces of the contraction joints and the cracks. The results indicated that for cracking with an extension depth of half the thickness of the dam body, for both cases of penetration and non-penetration of water load into the cracks, SFs only slightly reduces. However, in case of increasing the depth of crack extension into the entire thickness of the dam body, the friction angle of the cracked surface is crucial; however, if it reduces, the normal loading SFs of stresses and joints tractions reduce significantly.

Service Quality, Customer Satisfaction and Customer Loyalty of Mobile Communication Industry in China

Zhang, Ruijin,Li, Xiangyang,Zhang, Yunchang Korean Academy of Marketing Science 2010 마케팅과학연구 Vol.20 No.3

Previous studies have shown that the most important factor affecting customer loyalty in the service industry is service quality. However, on the subject of whether service quality has a direct or indirect effect on customer loyalty, scholars' views apparently vary. Some studies suggest that service quality has a direct and fundamental influence on customer loyalty (Bai and Liu, 2002). However, others have shown that service quality not only directly affects customer loyalty, it also has an indirect impact on customer loyalty by influencing customer satisfaction and perceived value (Cronin, Brady, and Hult, 2000). Currently, there are few domestic articles that specifically address the relationship between service quality and customer loyalty in the mobile communication industry. Moreover, research has studied customer loyalty as a whole variable, rather than breaking it down further into multiple dimensions. Based on this analysis, this paper summarizes previous study results, establishes an effect mechanism model among service quality, customer satisfaction, and customer loyalty in the mobile communication industry, and presents a statistical test on model assumptions by using customer investigation data from Heilongjiang Mobile Company. It provides theoretical guidance for mobile service management based on the discussion of the hypothesis test results. For data collection, the sample comprised mobile users in Harbin city, and the survey was taken by random sampling. Out of a total of 300 questionnaires, 276 (92.9%) were recovered. After excluding invalid questionnaires, 249 remained, for an effective rate of 82.6 percent for the study. Cronbach's ${\alpha}$ coefficient was adapted to assess the scale reliability, and validity testing was conducted on the questionnaire from three aspects: content validity, construct validity. and convergent validity. The study tested for goodness of fit mainly from the absolute and relative fit indexes. From the hypothesis testing results, overall, four assumptions have not been supported. The ultimate affective relationship of service quality, customer satisfaction, and customer loyalty is demonstrated in Figure 2. On the whole, the service quality of the communication industry not only has a direct positive significant effect on customer loyalty, it also has an indirect positive significant effect on customer loyalty through service quality; the affective mechanism and extent of customer loyalty are different, and are influenced by each dimension of service quality. This study used the questionnaires of existing literature from home and abroad and tested them in empirical research, with all questions adapted to seven-point Likert scales. With the SERVQUAL scale of Parasuraman, Zeithaml, and Berry (1988), or PZB, as a reference point, service quality was divided into five dimensions-tangibility, reliability, responsiveness, assurance, and empathy-and the questions were simplified down to nineteen. The measurement of customer satisfaction was based mainly on Fornell (1992) and Wang and Han (2003), ending up with four questions. Based on the study’s three indicators of price tolerance, first choice, and complaint reaction were used to measure attitudinal loyalty, while repurchase intention, recommendation, and reputation measured behavioral loyalty. The collection and collation of literature data produced a model of the relationship among service quality, customer satisfaction, and customer loyalty in mobile communications, and China Mobile in the city of Harbin in Heilongjiang province was used for conducting an empirical test of the model and obtaining some useful conclusions. First, service quality in mobile communication is formed by the five factors mentioned earlier: tangibility, reliability, responsiveness, assurance, and empathy. On the basis of PZB SERVQUAL, the study designed a measurement scale of service quality for the mobile communications industry, and obtained th ?有文?表明, 影?服???客忠?的最重要因素是服??量. 然而, 在服??量是直接?是?接影??客忠?方面, ?者?的?点有着明?的分?. 目前, 中???????移?通信行?服??量??客忠?之??系的文章?少. 此外, 以往相?文?多是??客忠?作?一?整??量?行?究, ?有?一步?其?分?多??度. 基于此, 本文?通????究?探析移?通信?服??量各?度??客忠?各?度之?的直接和?接影?机理, 其中???客?意作?二者?系的中介?量, 希望?究??能???移?通信企?的服?管理提供有效的理?指?. ?了使搜集到的?据有效, 本次??范??限于黑?江哈??市, ???象?移?通信公司的用?. 本次??采取?机抽?的方式, 共?放?卷350?, 收回?卷325?, 回收率? 92.9%. 剔除无效?卷, 有效?卷?289?, ?有效回收率?82.6%. 本文借???外?有文?所使用的量表, ?些量表已?在???究中得到??. 本文提出六?假?, ??而言, 只有四?假??有得到支持. ?了??服??量?成要素量表的合理性, 本文?289?有效?本?行探索性因子分析. 同?, ??客忠?的?度?行??. 本?究采用Cronbach's ${\alpha}$系???价量表的信度. 本?究??容效度, ??效度和聚合效度三方面??卷?行效度??. 本?究??据和模型的?合?度?行??, 以提高假???的准?程度. 通?文??料的收集, 整理及?据?理, 本文提出了服??量五?度模型以及服??量??客忠?度之?相互?系模型, 通???分析??了有形性, 可?性, 反?性, 保?性和??性是服??量的五??成要素, ??了PZB?于服??量的SERVQUAL的?量方法, ?究了移?通信服??量各?度??客忠?各?度的直接影?机理, 以及服??量各?度如何通??客?意?一中介?量??客忠?各?度的?接影?机理, 建立了相?的?系模型,??用??方程分析方法,?模型?行????, 得出如下?究??: 第一, 移?通信服??量由有形性, 可?性, ??性, 保?性和移情性五?要素?成, ?客忠?由?度忠?和行?忠????度?成. 在PZB??的SERVQUAL量表基?上, 本文??移?通信行???了服??量?量量表, 通?探索性因子分析得出五?因子. ?五?因子?五?成要素基本一致, ?明服??量五要素?念适用于移?通信行?. 同?, ??客忠?量表?行因子分析, 得出??因子, ?本文中的?度忠?和行?忠?相一致. 第二, 移?通信服??量??客忠?存在直接和?接的正向影?作用. 其中, 服??量??度忠?有直接和?接的正向作用, ?接作用是通??客?意?一中介?量影?的; 服??量?行?忠?有直接和?接的正向作用, ?接作用是通??客?意和?度忠????中介?量影?的. ??明移?通信服??量越好, ?客的?意度越高, 其?服?提供商的?度就越??, 在行?上就越容易表?出?服?提供商的忠?. 而且, 服??量各?度??客忠?各?度的影?机理是不同的, 比如: 有形性??客?意有直接的正向作用, 但??客忠?却?有?著的直接作用; 保?性??客?意?有?著的直接作用, 但??客忠?有直接和?接的正向作用. 第三, ?客?意在移?通信服??量??度忠?, 行?忠?之?的具有?著的中介作用, ??明服??量的提高可以增加?客的?意度, 而?意的?客更容易成?忠?的?客; 而?度忠?在移?通信服??量?行?忠?之?的具有?著的中介作用,

Rolling bearing fault convolutional neural network diagnosis method based on casing signal

Xiangyang Zhang,Guo Chen,Tengfei Hao,Zhiyuan He 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

Affected by the transmission path, it is very difficult to diagnose the vibration signal of the rolling bearing on the aircraft engine casing. A fault diagnosis method based on convolutional neural network is proposed for the weak vibration signal of the casing under the excitation of rolling bearing fault. Firstly, the processing method of vibration signal is studied. Through comparison and analysis, it is found that the fault characteristics of rolling bearing are more easily expressed by continuous wavelet scale spectrum, and a better recognition rate is obtained. Finally, the experiment was carried out with an aero-engine rotor tester with a casing, and the method based on wavelet scale spectrum and convolutional neural network was used for diagnosis. The results were compared with the support vector machine method. The results show that the method has a high recognition rate for the weak fault signals of different fault types collected on the aero engine case, and its fault recognition rate reaches 95.82 %, which verifies the superiority and potential of the method for rolling bearing fault diagnosis.

The drag characteristics prediction of multi-plate frictional wet clutches in vehicle transmissions

Minghui Zhang,Yanfang Liu,Tianyan Liu,Xiangyang Xu,Jin Xu,Yudong Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

The multi-plate frictional wet clutch is one of the most important components in automatic transmissions. With the increasing of the rotational speed, the phenomena is tested that the drag torque firstly increases to the peak torque, and then decreases to a lower level and maintains within a certain range, and finally increases rapidly again. A fluid-structure coupled model of the whole wet clutch was established. The simulation results show that the pressure distribution is obviously nonuniform either on the frictional surface or between two sides of the clutch plate. The nonuniform pressure would cause the axial and deflection motion and so the impact would occur, which is the main reason for the drag torque’s increasing under high rotational speed. Based on the simulated results, a prediction model was built with the direct artificial neural network method. The test results show that the drag characteristics prediction model is effective and fast.

Long term structural health monitoring for old deteriorated bridges: a copula-ARMA approach

Yi Zhang,Chul-Woo Kim,Lian Zhang,Yongtao Bai,Hao Yang,Xiangyang Xu,Zhenhao Zhang 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.3

Long term structural health monitoring has gained wide attention among civil engineers in recent years due to the scale and severity of infrastructure deterioration. Establishing effective damage indicators and proposing enhanced monitoring methods are of great interests to the engineering practices. In the case of bridge health monitoring, long term structural vibration measurement has been acknowledged to be quite useful and utilized in the planning of maintenance works. Previous researches are majorly concentrated on linear time series models for the measurement, whereas nonlinear dependences among the measurement are not carefully considered. In this paper, a new bridge health monitoring method is proposed based on the use of long term vibration measurement. A combination of the fundamental ARMA model and copula theory is investigated for the first time in detecting bridge structural damages. The concept is applied to a real engineering practice in Japan. The efficiency and accuracy of the copula based damage indicator is analyzed and compared in different window sizes. The performance of the copula based indicator is discussed based on the damage detection rate between the intact structural condition and the damaged structural condition.

The drag characteristics prediction of multi-plate frictional wet clutches in vehicle transmissions

Minghui Zhang,Tianyan Liu,Yanfang Liu,Xiangyang Xu,Jin Xu,Yudong Zhang 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

The drag characteristics prediction of multi-plate frictional wet clutches in vehicle transmissions

Minghui Zhang,Tianyan Liu,Yanfang Liu,Xiangyang Xu,Jin Xu,Yudong Zhang 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

Service Quality, Customer Satisfaction and Customer Loyalty of Mobile Communication Industry in China

Ruijin Zhang,Xiangyang Li,Yunchang Zhang 한국마케팅과학회 2010 마케팅과학연구 Vol.20 No.3

Previous studies have shown that the most important factor affecting customer loyalty of service industry is service quality. However, on the part whether service quality has a direct or indirect affect on customer loyalty, the scholars’ views vary apparently. Some studies suggest that service quality has a direct and fundamental influence on customer loyalty (Bai Changhong and Liu Zhi, 2002) ; but some studies have shown that service quality not only directly affects customer loyalty, but also indirectly impacts customer loyalty by influencing customer satisfaction and perceived value(Cronin et al., 2000) .Currently, there are less domestic articles specifically on the relationship between service quality and customer loyalty of mobile communication industry. Besides, literatures studied customer loyalty as a whole variable, not further breaking down into multiple dimensions. Based on this, this paper summarized previous study results, established an effect mechanism model among service quality, customer satisfaction and customer loyalty of mobile communication industry, and did a statistical test on model assumptions by using customer investigation data of Heilongjiang Mobile Company, which provides theoretical guidance for mobile service management based on the discussion of the hypothesis test results. For data collection, the sample was comprised of Harbin city, and the targets are mobile users. The survey is taken by random sampling. A total of 300 questionnaires were delivered, and 276 questionnaires were recovered, with a recovery rate of 92.9%. Excluding invalid questionnaires, 249 questionnaires were valid, which means the effective rate was 82.6%. This study adapted Cronbach's α coefficient to assess the scale reliability. This study conducted validity test on the questionnaire from three aspects: content validity, construct validity and convergent validity. This study tested goodness of fit mainly from the absolute and relative fit indexes. The hypotheses testing results of the study are shown . Overall, four assumptions have not been supported .The ultimate affective relationship of service quality, customer satisfaction and customer loyalty is demonstrated on figure 2. On the whole, the service quality of communication Industry not only has a direct positive significant affect on customer loyalty, but also has an indirect positive significant affect on customer loyalty by service quality; the affective mechanism and extent of customer loyalty are different which is affected by each dimension of service quality. This paper uses the questionnaires of existing literature from home and abroad, which have been tested in empirical research. All questions adapted seven points Liker-type. This article made reference to PZB SERVQUAL scale. Service quality is divided into five projects: tangibility, reliability, responsiveness, assurance and empathy, and questions are simplified into nineteen. The measurement of customer satisfaction mainly made reference to Fornell (1992) and Han Xiaoyun (2003) scale, and finally chose four questions. Based on the reference of Gronholdt (2000) and Wang Chunxiao (2004) scale, this paper chose three indicators such as price tolerance, first choice, and complaint reaction of to measure attitudinal loyalty, and chose three indicators such as repurchase intention, recommendation, and reputation to measure behavioral loyalty. Through collection and collation of literature data, this paper built a model of the relationship among service quality, customer satisfaction and customer loyalty of mobile communication, and took China Mobile in Harbin in Heilongjiang as conducting an empirical test on the model and obtaining some useful conclusions: First, service quality of mobile communication is formed by five factors: Tangibility, Reliability, Responsiveness, Assurance and Empathy.

Running safety of metro train over a high-pier bridge subjected to fluctuating crosswind in mountain city

Yunfei Zhang,Jun Li,Zhaowei Chen,Xiangyang Xu 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.2

Due to the rugged terrain, metro lines in mountain city across numerous wide rivers and deep valleys, resulting in instability of high-pier bridge and insecurity of metro train subjected to fluctuating crosswind. To ensure the safe operation in metro lines in mountain cities, running safety of the metro train over the high-pier bridge under crosswind is analyzed in this paper. Firstly, the dynamic model of the wind-train-bridge (WTB) system is built, in which the speed-up effect of crosswind is fully considered. On the basis of time domain analysis, the basic characteristics of the WTB system with high-pier are analyzed. Afterwards, the dynamic responses varies with train speed and wind speed are calculated, and the safety zone of metro train over a high-pier bridge subjected to fluctuating crosswind in mountain city is determined. The results indicate that, fluctuating crosswind triggers drastic vibration to the metro train and high-pier bridges, which in turn causes running instability of the train. For this reason, the corresponding safety zone for metro train running on the high-pier is proposed, and the metro traffic on the high-pier bridge should be closed as the mean wind speed of standard height reaches 9 m/s (15.6 m/s for the train).