Degradation and Drug-release Behavior of Polylactic Acid (PLA) Medical Suture Coating with Tea Polyphenol (TP) -Polycaprolactone (PCL)/Polyglycolide (PGA)

Shuqiang Liu,Gaihong Wu,Xiaofang Zhang,Juanjuan Yu,Mingfang Liu,Yao Zhang,Peng Wang,Xiaolong Yin 한국섬유공학회 2019 Fibers and polymers Vol.20 No.2

The drug-release time of suture should meet with the healing time of wound, so it is needed to control the drugrelease performance of polylactic acid (PLA) suture. In this paper, two biodegradable polymers with different degradation rates, such as polycaprolactone (PCL) and polyglycolide (PGA), were applied to carry the drug of tea polyphenol (TP). The drug-loading finishing solution which is made of PCL/PGA carriers and TP, was coated on the PLA suture. The drug-release rate and time of PLA suture could be regulated by adjusting the proportion of PCL/PGA carriers. The results indicate that thesurface of drug-loaded PLA suture becomes rough. There is no obvious chemical reaction among the drug, carriers and PLA suture, just physical adhesion. With the increasing of PCL in drug-carriers, the strength of suture gradually increases. At 70/30 of PCL/PGA, the fracture elongation of suture reaches the highest point. In process of degradation, the surface of drugloaded PLA suture appears some holes after 25 weeks. The strength of sutures decreases gradually during degradation, and the effective strength time of sutures with various proportions of PCL/PGA is different. The drug-release rate of the suture isfast at early stage and slow at later stage and the higher the PGA proportion is, the faster the drug-release rate of the suture is.

Removal of Co(II) from aqueous solutions by sulfonated magnetic multi-walled carbon nanotubes

Juanjuan Yang,Yunhui Dong,Jun Li,Zhengjie Liu,Fanlian Min,Yueyun Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.11

Sulfonated magnetic multi-walled carbon nanotubes (SMMWCNTs) were applied in the sorption of Co(II) from aqueous solutions. The SMMWCNTs were prepared and characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR), and X-ray diffractometer (XRD) test. A large number of influencing factors to the sorption process were investigated, such as pH, ionic strength, contact time, cations, anions, humic acid (HA), fulvic acid (FA) and temperature. The results indicated that the Co(II) sorption was strongly controlled by the pH and ionic strength. Moreover, foreign anions, such as F−, Cl− and Br−, had an obvious effect on the sorption process, which depended on the electronegativity of the anions. On the other hand, cations restrained sorption strongly, such as Mg2+ and Ca2+. The existence of HA/FA enhanced sorption process at pH<8 while weakened at pH>8. As revealed by the sorption results, the Langmuir adsorption model was more favorable than the Freundlich adsorption model, and the pseudo-second-order model could fit the data much better than the pseudo-first-order. The thermodynamic analysis suggested that sorption was spontaneous and endothermic. What’s more, the stability experiments of the SMMWCNTs showed that SMMWCNTs could maintain excellent magnetic stability and dispersion stability. Thus, this SMMWCNTs sorbent was believed to be a promising material for the selective removal of Co(II) from heavy metal-containing wastewater.

The relationship of Rockfall Scars Structure with Magnitude - Cumulative - Frequency

( Juanjuan Sun ),( Xueliang Wang ),( Haiyang Liu ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

Rockfalls are exist universally in mountain regions, steep cliffs and rock slopes with a high risk of personal safety and severely destructive of property or infrastructures. The rock mass instability and different magnitude rockfalls frequency are closely related to the rock mass structural geometry character. With the development of three - dimension rockfall modeling algorithms and tools during the last decade, we could see more about bedrock failure mechanisms and rockfall frequency under the control of rockfall scars geometry. Based the three-dimensional real scene model data of UAV point cloud, block size, volumetric joint count, joints spacing and average length of joints are carried out with statistical analysis. In this paper, we discuss cumulative frequency relation of the block size, volumetric joint count, and joints spacing, found that the block size and the volumetric joint count are follow power law distribution, with the exponent b adjusted in the range of 0.5~0.9 and 0.4~0.6, respectively. We establish the relationship of rockfall scars structure with rockfall frequency, assess its suitability. The relation can be used as a preliminary method to estimate the rockfall frequency.

Contribution of Shear Reinforcements and Concrete to the Shear Capacity of Interfaces between Concretes Cast at Different Times

Jie Liu,Yangmin Bu,Juanjuan Chen,Qing Wang 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.6

Currently, shear transfer models have diverse assumptions about the contribution of shear reinforcements and concrete to the shear capacity of interfaces between concretes cast at different times (that is, cold joints). Furthermore, the knowledge about the effect of high–strength shear reinforcements (HSSR) having a nominal yield strength exceeding 414 MPa (60 ksi), is still limited. This study aims to determine the extent to which shear reinforcements and concrete contribute to the shear capacity of cold joints and explore the effect of HSSR on shear transfer behavior. To this end, nine cold joint push–off specimens were tested to investigate the effects of yield strength of shear reinforcement (YSSR) and concrete compressive strength (CCS) on the interface shear strength and stiffness. In addition, code provisions evaluation was used to identify the degree of concrete contribution, based on a database of 108 cold joint push–off test results established in this study. Test results indicate that the increase of YSSR (rising from 400 MPa to 600 MPa) has no evident effect on the shear strength and stiffness of cold joints, whereas the increase of CCS can significantly increase them. Moreover, when CCS rises from 20 MPa to 50 MPa, the interface shear capacity of push–off specimens increases by approximately 110%, i.e., from 103.5 kN to 217.5 kN. Hence, concrete has a considerable contribution, whereas the contribution of shear reinforcements is not as great as expected. Code provisions evaluation results also indicate that concrete considerably contributes to the shear capacity in the form of cohesion. On the basis of these findings and current design equations, a shear capacity equation, which accounts for the effect of CCS and the limited participation of shear reinforcements, is proposed. This equation is found to provide reasonable prediction of cold joint shear capacity, especially for the cold joint composed of high–strength concrete.

Stackelberg Strategy of Two-player Stochastic Difference Game With Time Delay

Jingmei Liu,Wei Wang,Juanjuan Xu,Huanshui Zhang 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.9

In this paper, we study the open-loop Stackelberg strategy of the stochastic Stackelberg game with time delay. The main contribution is to give the explicit Stackelberg strategy in terms of Riccati equations. The key to solving the problem is the explicit solvability of the forward and backward stochastic difference equations (FBSDEs). Moreover, the optimal costs are indicated by using the initial value of the state.

CUSTOMER ENGAGEMENT AND ITS OUTCOMES: THE ROLES OF SERVICE ENVIRONMENT AND BRAND EQUITY

Ou Juanjuan,IpKin Anthony Wang,Matthew Tingchi Liu 글로벌지식마케팅경영학회 2018 Global Marketing Conference Vol.2018 No.07

Engineering Bifunctional Antibodies with Constant Region Fusion Architectures

Du, Juanjuan,Cao, Yu,Liu, Yan,Wang, Ying,Zhang, Yong,Fu, Guangsen,Zhang, Yuhan,Lu, Lucy,Luo, Xiaozhou,Kim, Chan Hyuk,Schultz, Peter G.,Wang, Feng American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.51

<P>We report a method to generate bifunctional antibodies by grafting full-length proteins into constant region loops of a full-length antibody or an antigen-binding fragment (Fab). The fusion proteins retain the antigen binding activity of the parent antibody but have an additional activity associated with the protein insert. The engineered antibodies have excellent <I>in vitro</I> activity, physiochemical properties, and stability. Among these, a Her2 × CD3 bispecific antibody (BsAb) was constructed by inserting an anti-Her2 single-chain variable fragment (ScFv) into an anti-CD3 Fab. This bispecific antibody efficiently induces targeted cell lysis in the presence of effector cells at as low as sub-picomolar concentrations <I>in vitro</I>. Moreover, the Her2 × CD3 BsAb shows potent <I>in vivo</I> antitumor activity in mouse Her2<SUP>2+</SUP> and Her2<SUP>1+</SUP> xenograft models. These results demonstrate that insertion of a full-length protein into non-CDR loops of antibodies provides a feasible approach to generate multifunctional antibodies for therapeutic applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2017/jacsat.2017.139.issue-51/jacs.7b09641/production/images/medium/ja-2017-09641x_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja7b09641'>ACS Electronic Supporting Info</A></P>

Stability criterion and its calculation for sail-assisted ship

Yihuai Hu,Juanjuan Tang,Shuye Xue,Shewen Liu 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.1

Stability criterion and its calculation are the crucial issue in the application of sail-assisted ship. However, there is at present no specific criterion and computational methods for the stability of sail-assisted ship. Based on the stability requirements for seagoing ships, the stability criterion of the sail-assisted ships is suggested in this paper. Furthermore, how to calculate the parameters and determine some specific coefficients for the ship stability calculation, as well as how to redraw stability curve are also discussed in this paper. Finally, to give an illustration, the proposed method is applied on a sail assisted-ship model with comments and recommendations for improvement.

Finite Element Analysis and Dynamics Simulation of Mechanical Flux-Varying PM Machines with Auto-Rotary PMs

Huang, Chaozhi,Zhang, Zhixuan,Liu, Xiping,Xiao, Juanjuan,Xu, Hui The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3

A new type of auto-rotary PM mechanical flux-varying PM machine (ARPMMFVPMM) is proposed in this paper, which can overcome the problem where the air-gap magnetic field of a PM machine is difficult to freely adjust. The topology structures of the machine and the mechanical flux-adjusting device are given. In addition, the operation principle of flux-adjusting is analyzed in detail. Furthermore, the deformation of a spring with the speed variation is obtained by virtual prototype technology. Electromagnetic characteristics including the flux distribution, air gap flux density, flux linkage, electromagnetic-magnetic-force (EMF), and flux weakening ability are computed by 2D finite element method (FEM). Results show that the machine has some advantages such as the good field control ability.

Stability criterion and its calculation for sail-assisted ship

Hu, Yihuai,Tang, Juanjuan,Xue, Shuye,Liu, Shewen The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.1

Stability criterion and its calculation are the crucial issue in the application of sail-assisted ship. However, there is at present no specific criterion and computational methods for the stability of sail-assisted ship. Based on the stability requirements for seagoing ships, the stability criterion of the sail-assisted ships is suggested in this paper. Furthermore, how to calculate the parameters and determine some specific coefficients for the ship stability calculation, as well as how to redraw stability curve are also discussed in this paper. Finally, to give an illustration, the proposed method is applied on a sail assisted-ship model with comments and recommendations for improvement.