Polyetheretherketone implants with hierarchical porous structure for boosted osseointegration

Zhiyong Chen,Yu Chen,Yang Wang,JiaJia Deng,Xin Wang,Qingqing Wang,Yuehua Liu,Jiandong Ding,Lin Yu 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Good osseointegration is the key to the long-term stability of bone implants. Thermoplastic polyetheretherketone (PEEK) has been widely used in orthopedics; however, its inherent biological inertia causes fibrous tissue to wrap its surface, which leads to poor osseointegration and thus greatly limits its clinical applications. Methods Herein, we developed a facile yet effective surface modification strategy. A commonly used sulfonation coupled with “cold pressing” treatment in the presence of porogenic agent formed a three-dimensional hierarchical porous structure on PEEK surface. Subsequently, the effects of porous surface on the in vitro adhesion, proliferation and differentiation of rat bone marrow-derived mesenchymal stem cells (BMSCs) were evaluated. Finally, the osteoinduction and osseointegration of surface-porous PEEK implant were examined in the rat distal femoral defect model. Results In vitro results showed that the surface modification did not significantly affect the mechanical performance and cytocompatibility of PEEK substance, and the porous structure on the modified PEEK substrate provided space for cellular ingrowth and enhanced osteogenic differentiation and mineralization of BMSCs. In vivo tests demonstrated that the surface-porous PEEK implant could effectively promote new bone formation and had higher bone-implant contact rate, thereby achieving good bone integration with the surrounding host bone. In addition, this modification technique was also successfully demonstrated on a medical PEEK interbody fusion cage. Conclusion The present study indicates that topological morphology plays a pivotal role in determining implant osseointegration and this facile and effective modification strategy developed by us is expected to achieve practical applications quickly.

Ordered Arrays of Dual-Diameter Nanopillars for Maximized Optical Absorption

Fan, Zhiyong,Kapadia, Rehan,Leu, Paul W.,Zhang, Xiaobo,Chueh, Yu-Lun,Takei, Kuniharu,Yu, Kyoungsik,Jamshidi, Arash,Rathore, Asghar A.,Ruebusch, Daniel J.,Wu, Ming,Javey, Ali American Chemical Society 2010 Nano letters Vol.10 No.10

<P>Optical properties of highly ordered Ge nanopillar arrays are tuned through shape and geometry control to achieve the optimal absorption efficiency. Increasing the Ge materials filling ratio is shown to increase the reflectance while simultaneously decreasing the transmittance, with the absorbance showing a strong diameter dependency. To enhance the broad band optical absorption efficiency, a novel dual-diameter nanopillar structure is presented, with a small diameter tip for minimal reflectance and a large diameter base for maximal effective absorption coefficient. The enabled single-crystalline absorber material with a thickness of only 2 μm exhibits an impressive absorbance of ∼99% over wavelengths, λ = 300−900 nm. These results enable a viable and convenient route toward shape-controlled nanopillar-based high-performance photonic devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2010/nalefd.2010.10.issue-10/nl1010788/production/images/medium/nl-2010-010788_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl1010788'>ACS Electronic Supporting Info</A></P>

Consensus of Multi-agent Systems with Feedforward Nonlinear Dynamics and Digraph

Shuzhen Yu,Haijun Jiang,Zhiyong Yu,Cheng Hu 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

This paper considers a high-order consensus problem of multi-agent system with feedforward nonlinear and time-varying input delay in a directed network. In order to achieve the consensus, we propose a low gain distributed protocol which can get rid of impacts of feedforward nonlinearity and an arbitrarily bounded input delay on the consensus problem. Moreover, for any upper bound time-varying delay and strongly connected diagraph, the proposed controller can solve the consensus problem of multi-agent systems with feedforward nonlinearity if the designed parameter q is great than the threshold value. Finally, several numerical simulations are presented to demonstrate the validity of the theoretical results.

Feeling In Control : Design Tangible Self-Health Management Service Touch-Points For The Elderly With Holistic Experience

Zhiyong Fu,Dandan Yu,Shuangshuang Zhang 한국HCI학회 2013 한국HCI학회 학술대회 Vol.2013 No.1

This paper presents how to improve the holistic user experience for the elderly with chronic disease by designing the new self-health management service based on multi-screen platform and tangible touch points. As the connected touch point, Med-Cube is designed to help the elderly feel in control when they handle with the complicated multi-screen devices, like TV, tablet PC and mobile phone. In order to create seamless connection between the elderly and the multi-screen service system, we designed the context aware interaction flow based on the elderly’s common experience and behavior of everyday self-health management, such as recording, reminding and navigating. This selfhealth service system helps the elderly to create integrated user experience between virtual online world and physical world as well. The self-health service system also links the elderly with family, friends and doctors by cross-media platform and social network. Our vision in this study is to give the elderly independent, healthy, self-controlled life by providing service from the tangible touch points and holistic cross-media interaction mode.

Fabrication of 30 nm pitch imprint moulds by frequency doubling for nanowire arrays

Yu, Zhaoning,Wu, Wei,Jung, Gun-Young,Olynick, D L,Straznicky, J,Li, Xuema,Li, Zhiyong,Tong, William M,Liddle, J A,Wang, Shih-Yuan,Stanley Williams, R IOP Pub 2006 Nanotechnology Vol.17 No.19

<P>We report the fabrication of 30 nm pitch nanowire array imprint moulds by spatial frequency doubling a 60 nm pitch array generated by electron beam lithography. We have successfully fabricated nanowire arrays at a 30 nm pitch, which is targeted for the year 2020 by the International Technology Roadmap for Semiconductors, with an average line-width of 17 nm and a 3σ line width roughness (LWR) of 4.0 nm. In contrast to previously reported procedures, our spatial frequency doubling technique produces electrically isolated nanowires that are appropriate for crossbar circuits. </P>

STABLE AND ROBUST ℓ_p-CONSTRAINED COMPRESSIVE SENSING RECOVERY VIA ROBUST WIDTH PROPERTY

Yu, Jun,Zhou, Zhiyong Korean Mathematical Society 2019 대한수학회지 Vol.56 No.3

We study the recovery results of ${\ell}_p$-constrained compressive sensing (CS) with $p{\geq}1$ via robust width property and determine conditions on the number of measurements for standard Gaussian matrices under which the property holds with high probability. Our paper extends the existing results in Cahill and Mixon from ${\ell}_2$-constrained CS to ${\ell}_p$-constrained case with $p{\geq}1$ and complements the recovery analysis for robust CS with ${\ell}_p$ loss function.

Effects of raw meat and process procedure on N^ε-carboxymethyl-lysine and N^ε-carboxyethyl-lysine formation in meat products

Yu, Ligang,Gao, Chang,Zeng, Maomao,He, Zhiyong,Wang, Linxiang,Zhang, Shuang,Chen, Jie 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.4

This work aimed to investigate the effects of stored raw meat and process procedures on $N^{\varepsilon}$-carboxymethyl-lysine (CML) and $N^{\varepsilon}$-carboxyethyl-lysine (CEL) generation in meat products. Meat products of raw pork were sterilized and pasteurized at different storage times (0-4 months) and the CML/CEL contents were determined. The results showed that the extent of lipid and protein oxidation of raw pork increased with increasing storage time. A linear correlation was found between thiobarbituric acid-reactive substances value/carbonyl content and CML/CEL in sterilized meat products, indicating that stored raw pork could promote CML/CEL formation under high temperature processing. Furthermore, mild heating temperatures seemed to favor CML formation, while high temperature could accelerate CEL generation. Therefore, formation kinetics of CML and CEL might be different for different process procedures. These results suggested that stored raw meat and processing temperature could significantly affect CML and CEL generation in meat products.

Enhanced Curdlan Production in Agrobacterium sp. ATCC 31749 by Addition of Low-polyphosphates

Lijun Yu,Jianrong Wu,Jia Liu,Xiaobei Zhan,Zhiyong Zheng,Chi Chung Lin 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.1

A large amount of adenosine triphosphate with high energy phosphate bonds is required for uridine triphosphate regeneration during curdlan biosynthesis by Agrobacterium sp. ATCC 31749. To supply high energy for curdlan synthesis, three low-polyphosphates (Na_4P_2O_7,Na_5P_3O_10, and (NaPO_3)_6) with higher energy phosphate bonds were employed to substitute for KH_2PO_4-K_2HPO_4in fermentation medium. Two genes encoding the polyphosphate metabolizing enzymes, polyphosphate kinase and exopolyphosphatase, were amplified and showed 95%homology to those in Agrobacterium sp. C58 by sequence analysis. The curdlan yields were enhanced by 23 and 134% when phosphate concentrations 0.024 mol/L of Na_5P_3O_10 and 0.048 mol/L of (NaPO_3)_6 respectively, were added in the medium. The maximum curdlan yield of 30 ±1.02 g/L was obtained with the addition of 0.048 mol/L of (NaPO_3)_6 with 5 g/L CaCO_3 in the medium. When CaCO_3 was removed from the culture and the three lowpolyphosphates were added, the pH and biomass yield dropped remarkably and little or no curdlan was produced. The culture containing 0.048 mol/L of (NaPO_3)_6 was mixed with KH_2PO_4-K_2HPO_4 and CaCO_3 in the medium,but showed no effect on curdlan production. However,curdlan yield was improved by 49 ~ 60% when CaCO_3was removed from the medium and KH_2PO_4-K_2HPO_4acted as a buffer. It appears that the positive effect of (NaPO_3)_6 on curdlan production required the buffering capacity of CaCO_3 and the absence of KH_2PO_4-K_2HPO_4competing as a phosphate supplier.

Attack Graph Algorithm in the Application of Intrusion Detection System

Luo Zhiyong,You Bo,Xu Jiazhong,Yu Guixin,Liu Yahui 보안공학연구지원센터 2013 International Journal of Security and Its Applicat Vol.7 No.5

The Research of the Recommendation Algorithm in Online Learning

Ruiguo Yu,Zhiyong Cai,Xiuping Du,Muwen He,Zan Wang,Binlan Yang,Peng Chang 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.4

Recommendation algorithm is a kind of method in information filtering and has been widely applied on Internet. Collaborative filtering is widely used in the recommendation systems and has turned out to be successful. With the growth of the resources, it is difficult for users to find learning resources that suit for themselves. The recommendation algorithm is required to analyze the behavior of the users and then recommend object of learning. Online judge is a kind of the online learning. People can evaluate their programming ability through online judge. The performance of the different recommendation algorithms is analyzed in this paper and it is proposed that the item-based collaborative filtering recommendation algorithms should be applied into the online learning system. Based on the algorithm, we propose that by pre-processing the data and using user data that have solve large number of problems, we can get a better recommendation result.