D-RADA16-RGD-Reinforced Nano-Hydroxyapatite/Polyamide 66 Ternary Biomaterial for Bone Formation

Bo Qiao,Bin He,Ao Zhou,Yuling Li,Xiaojun Chen,Qiming Yang,Beike Chen,Bo Qiao,Dianming Jiang 한국조직공학과 재생의학회 2019 조직공학과 재생의학 Vol.16 No.2

BACKGROUND: Nano-hydroxyapatite/polyamide 66 (nHA/PA66) is a composite used widely in the repair of bone defects. However, this material is insufficient bioactivity. In contrast, D-RADA16-RGD self-assembling peptide (DRADA16- RGD sequence containing all D-amino acids is Ac-RADARADARADARADARGDS-CONH2) shows admirable bioactivity for both cell culture and bone regeneration. Here, we describe the fabrication of a favorable biomaterial material (nHA/PA66/D-RADA16-RGD). METHODS: Proteinase K and circular dichroism spectroscopy were employed to test the stability and secondary structural properties of peptide D-RADA16-RGD respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the surface of these materials. Confocal laser scanning (CLS), cell counting kit-8 tests (CCK-8), alizarin red S staining, cell immunofluorescence analysis and Western blotting were involved in vitro. Also biosafety and bioactivity of them have been evaluated in vivo. RESULTS: Proteinase K and circular dichroism spectroscopy demonstrated that D-RADA16-RGD in nHA/PA66 was able to form stable-sheet secondary structure. SEM and TEM showed that the D-RADA16-RGD material was 7–33 nm in width and 130–600 nm in length, and the interwoven pore size ranged from 40 to 200 nm. CLS suggests that cells in nHA/PA66/ D-RADA16-RGD group were linked to adjacent cells with more actin filaments. CCK-8 analysis showed that nHA/PA66/ D-RADA16-RGD revealed good biocompatibility. The results of Alizarin-red S staining and Western blotting as well as vivo osteogenesis suggest nHA/PA66/D-RADA16-RGD exhibits better bioactivity. CONCLUSION: This study demonstrates that our nHA/PA66/D-RADA16-RGD composite exhibits reasonable mechanical properties, biocompatibility and bioactivity with promotion of bone formation.

Achieving controllable degradation of a biomedical magnesium alloy by anodizing in molten ammonium bifluoride

Jiang, Heng Bo,Wu, Guosong,Lee, Sang-Bae,Kim, Kwang-Mahn Elsevier 2017 Surface & coatings technology Vol.313 No.-

<P><B>Abstract</B></P> <P>Magnesium (Mg) and its alloys as biodegradable metallic materials have attracted fundamental research in the field of orthopedics and cardiovascular materials. However, magnesium implants exhibit poor corrosion resistance, especially in the physiological environment, which limits medical applications. To improve the corrosion resistance of the Mg, anodization was applied to an ultra-high concentration of fluoride electrolyte. Then, surface morphology, coating thickness and composition were determined, and the corrosion behavior of anodized Mg alloys was evaluated. The results of coating by anodization showed that a porosity structure with a pore size of 600–900nm and thickness of 1–14μm is generated on the Mg alloy substrate, and this coating component is magnesium fluoride. In electrochemical corrosion tests and immersion corrosion tests, the anodized Mg alloy was tested, and the anodized Mg alloy shows significantly improved corrosion resistance compared with untreated Mg alloy in simulated body fluid (SBF).</P> <P><B>Highlights</B></P> <P> <UL> <LI> A porous MgF<SUB>2</SUB> coating is created on Mg alloy by anodization in molten fluoride salt. </LI> <LI> The anodizing time is <30s. </LI> <LI> Corrosion resistance of the anodized Mg alloy is obviously improved. </LI> </UL> </P>

Microstructural Characterization and Softening Mechanism of Ultra-Low Carbon Steel and the Control Strategy in Compact Strip Production Process

Bo Jiang,Xuewen Hu,Guoning He,Huan Peng,Haibo Wang,Yazheng Liu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.9

In this paper, the microstructures and properties of hot rolled ultra-low carbon steel sheet produced by different compact stripproduction (CSP) processes were investigated. The softening mechanism was also discussed and the control strategy wasproposed in order to obtain optimum properties. Result showed that the average ferrite grain sizes of austenite rolling sheetand multiphase rolling sheet were 31.0 μm and 74.6 μm, respectively. The sheet after austenite rolling had a slightly higheryield and tensile strength while had a 6.3% higher elongation than that of the sheet after multiphase rolling. The higher dislocationin the sheet after multiphase rolling increased the strength while decreased the elongation. The softening mechanismof the sheet after multiphase rolling was the coarsening of ferrite grain. The combined role of {001} and {111} orientationresulted in a slight increase of the r and ̄rvalue in the sheet after multiphase rolling. It was a wise choice to conduct rollingat the Ac1temperature in CSP process to increase the grain size and decrease the dislocation density. Then, the strength ofthe sheets could be further reduced and the elongation could also be improved.

Prediction Model of Austenite Growth and the Role of MnS Inclusions in Non- Quenched and Tempered Steel

Bo Jiang,Meng Wu,He Sun,Zhilin Wang,Zhigang Zhao,Yazheng Liu 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.1

The austenite growth behavior of non-quenched and tempered steels (casted by continuous casting and moldingcasting processes) was studied. The austenite grain size of steel B casted by continuous casting process is smallerthan that of steel A casted by molding casting process at the same heating parameters. The abnormal austenitegrowth temperature of the steels A and B are 950 °C and 1000 °C, respectively. Based on the results, the models forthe austenite grain growth below and above the abnormal austenite growth temperature of the investigated steelswere established. The dispersedly distributed fine particles MnS in steel B is the key factor refining the austenitegrain by pinning the migration of austenite grain boundary. The elongated inclusions MnS are ineffective in preventingthe austenite grain growth at high heating temperature. For the non-quenched and tempered steel, the continuouscasting process should be adopted and the inclusion MnS should be elliptical, smaller in size anddistributed uniformly in order to refine the final microstructure and also improve the mechanical properties.

On equivalence of predictors/estimators under a multivariate general linear model with augmentation

Bo Jiang,Yongge Tian 한국통계학회 2017 Journal of the Korean Statistical Society Vol.46 No.4

Assume that a true multivariate general linear model for an observed random matrix is over-parameterized by adding some new regressors due to model uncertainty. Then predictors and estimators of parameter spaces in the true and over-parameterized models are not necessarily the same. In this article, we study the comparison problem of predictors/ estimators of parameter spaces under the two models. In particular, we derive necessary and sufficient conditions for the best linear unbiased predictors/best linear unbiased estimators of the parameter spaces to be equivalent under the two models.

A Study on the Influence of Personality Traits of College Students on the Way of Coping with Employment Stress and Entrepreneurial Intention in the Post-Epidemic Era

Jiang-Bo Yan,Ya-Li Fang,Chi Gong 사회혁신기업연구원 2023 혁신기업연구 Vol.8 No.2

With the arrival of the "post-epidemic era", the impact of multiple factors such as the epidemic and domestic and foreign economic weakness on the employment and entrepreneurship of graduates is still continuing and deepening, and youth employment has become a worldwide problem. Self-employment has gradually become a new employment channel, and self-employment of college students not only provides a large number of new jobs for the society, but also helps to alleviate the social employment pressure and the severe employment situation of college students. At present, exploring the factors influencing college students' entrepreneurial intention has become a hot topic in the field of entrepreneurship research. In this study, it is important to study the mechanism of each factor by constructing a model of the influencing factors of college students' entrepreneurial intention. The main conclusions from the study are as follows. First, all four personality traits have a significant positive influence on entrepreneurial intention, and college students with the above personality traits are more likely to have entrepreneurial intention, and the way of coping with employment pressure plays a mediating role in the relationship between personality traits and entrepreneurial intention. Based on this, the study provides valuable theoretical implications for research in this area and practical implications for how schools can improve students' entrepreneurial awareness.

Effect of Transformation Temperature on the Ferrite–Bainite Microstructures, Mechanical Properties and the Deformation Behavior in a Hot-Rolled Dual Phase Steel

Bo Jiang,Xuewen Hu,Leyu Zhou,Haibo Wang,Yazheng Liu,Fugang Gou 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.2

The ferrite–bainite microstructures and mechanical properties in a hot-rolled dual phase steel with different transformationtemperatures were investigated in this paper. The deformation behavior of bainite and ferrite was analyzed by using in situscanning electron microscope. The results showed that the ferrite and bainite can be refined and the volume fraction of bainitecan be slightly increased by 5% by decreasing the ferrite transformation temperature from 690 to 635 °C and increasing thebainite transformation temperature from 400 to 450 °C. The strengthening mechanism was dislocation difference in polygonaland acicular ferrite and then the grain size difference of ferrite. The hole expansion ratio increased from 52.9 to 83.7% withthe ferrite transformation temperature decreasing. The cracks or voids were smaller in size and also the number in steel withthe lower ferrite transformation temperature after expanding. The microstructure separation along the boundary betweenbainite and ferrite and the slip band in the ferrite appeared at the non-uniform deformation stage. However, fewer appearedin the microstructure of steel with lower ferrite transformation temperature. Cooperative deformation of ferrite and bainiteand finer microstructure in steel with lower ferrite transformation temperature were the mechanisms why the cracks couldnot easily nucleated and propagated, respectively. Thus this was also why there was a better hole expansion ratio.

Isolation, Culture and Identification of Porcine Skeletal Muscle Satellite Cells

Bo-jiang Li,Ping-hua Li,Rui=hua Huang,Wen-xing Sun,Han Wang,Qi-fa Li,Jie Chen,Wang Jun Wu,Honglin Liu 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.8

The objective of this study was to establish the optimum protocol for the isolation and culture of porcine muscle satellite cells. Mononuclear muscle satellite cells are a kind of adult stem cell, which is located between the basal lamina and sarcolemma of muscle fibers and is the primary source of myogenic precursor cells in postnatal muscle. Muscle satellite cells are a useful model to investigate the mechanisms of muscle growth and development. Although the isolation and culture protocols of muscle satellite cells in some species (e.g. mouse) have been established successfully, the culture system for porcine muscle satellite cells is very limited. In this study, we optimized the isolation procedure of porcine muscle satellite cells and elaborated the isolation and culture process in detail. Furthermore, we characterized the porcine muscle satellite cells using the immunofluorecence. Our study provides a reference for the isolation of porcine muscle satellite cells and will be useful for studying the molecular mechanisms in these cells.

융해용착모델링 기반 3D 프린팅 공정의 품질 지배인자 도출에 관한 실험적 연구

Jiang Bo,남정수(Jung Soo Nam),김정섭(Jung Sub Kim),이상원(Sang Won Lee) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.5

Design and Implementation of Transfusion Auxiliary Device by Patient Manual Control Dressing Change

Jiang Jin-gang,Shen Rui-chao,Wang Bao-fu,Gu Bo-yang,Tang Hai-bo,Jiang Ze-hao 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.11

Transfusion auxiliary device by patient manual control dressing is proposed. It is realized by one-way rotation ratchet mechanism, which is consistent of slider-crank mechanism and double pawl ratchet mechanism. Dressing change is automatically realized by patient manual control rope. This reduces the labor intensity of the medical staff, shortens the waiting time of the patients. This device has the advantage of low cost, large market space.