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.

Examining Stock Volatility in the Segmented Chinese Stock Markets: A SWARCH Approach

ZHUO QIAO,WEIWEI QIAO,Wing-Keung Wong 연세대학교 동서문제연구원 2010 Global economic review Vol.39 No.3

This study adopts the SWARCH model to examine the volatile behavior and volatility linkages among the four major segmented Chinese stock indices.We find strong evidence of a regime shift in the volatility of the four markets, and the SWARCH model appears to outperform standard generalized autoregressive conditional heteroskedasticity (GARCH) family models. The evidence suggests that, compared with the A-share markets, B-share markets stay in a high-volatility state longer and are more volatile and shift more frequently between high- and low-volatility states. In addition, the relative magnitude of the high-volatility compared with that of the low-volatility state in the B-share markets is much greater than the case in the two A-share markets. B-share markets are found to be more sensitive to international shocks, while A-share markets seem immune to international spillovers of volatility. Finally, analyses of the volatility spillover effect among the four stock markets indicate that the A-share markets play a dominant role in volatility in Chinese stock markets.

Knockdown of the M2 Isoform of Pyruvate Kinase (PKM2) with shRNA Enhances the Effect of Docetaxel in Human NSCLC Cell Lines In Vitro

Tiankui Qiao,Tiankui Qiao,Xibing Zhuang,Wei Chen,Na Xing,Qi Zhang 연세대학교의과대학 2016 Yonsei medical journal Vol.57 No.6

Purpose: The aim of our study was to explore the relationships between the M2 isoform of pyruvate kinase (PKM2) and the sensitivityof human non-small cell lung cancer (NSCLC) cells to docetaxel in vitro. Materials and Methods: With the method of plasmid transfection, we silenced the expression of PKM2 successfully in A549 and H460 cells. Western blotting and real-time PCR were applied to detect PKM2 expression at protein and gene levels. Cell viability was examined by CCK8 assay. Cell cycle distribution and apoptosis were examined by flow cytometry. P21 and Bax were detected. Results: Expression of PKM2 mRNA and protein were significantly decreased by shRNA targeting PKM2. Silencing of PKM2 increaseddocetaxel sensitivity of human NSCLC A549 and H460 cells in a collaborative manner, resulting in strong suppression of cell viability. The results of flow cytometric assays suggested that knockdown of PKM2 or docetaxel treatment, whether used singlyor in combination, blocked the cells in the G2/M phase, which is in consistent with the effect of the two on the expression of p21. Cells with PKM2 silencing were more likely to be induced into apoptosis by docetaxel although knockdown of PKM2 alone can’t induce apoptosis significantly, which is in consistent with the effect of the two on Bax expression. Conclusion: The results suggest that PKM2 knockdown could serve as a chemosensitizer to docetaxel in non-small lung cancer cells through targeting PKM2, leading to inhibition of cell viability, increase of cell arrest of G2/M phase and apoptosis.

Examining the Day-of-the-Week Effects in Chinese Stock Markets: New Evidence from a Stochastic Dominance Approach

ZHUO QIAO,WEIWEI QIAO,Wing-Keung Wong 연세대학교 동서문제연구원 2011 Global economic review Vol.40 No.3

Many researchers have investigated the existence of day-of-the-week effects in different financial markets. However, they have usually adopted a parametric approach, which is known to have a few limitations. This paper adopts a non-parametric stochastic dominance (SD) approach to examine the day-of-the-week effects in Chinese stock markets. In contrast to the extensive evidence of day-of-the-week effects disclosed by a parametric mean-variance (MV) approach, our SD tests show that the day-of-the-week effect is much weaker. We find that there are only Wednesday effects in Chinese A-share and B-share stock markets.

Ceratovacuna atrovirensa Qiao, a new species from China (Aphididae: Hormaphdinae)

Jiang Li-Yun,Chen Jing,Xu Ying,Qiao Ge-xia 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.3

Ceratovacuna atrovirensa Qiao sp.n., a woolly aphid on Indocalamus tessellatus from China, is described and illustrated. The new species is supported by both morphological and molecular data. An updated key to apterous viviparous females of Ceratovacuna is provided. The type specimens are deposited in the National Zoological Museum of China, Institute of Zoology, the Chinese Academy of Sciences, Beijing, China and the Natural History Museum, London, United Kingdom.

A Simplified Friction Model for Tripod Constant Velocity Joint

Qiao-Chu Cai,Chul-Hee Lee 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

As the tripod constant velocity (TCV) joint offer the lower plunge resistance compared to the ball joint, it has good behavior in noise and vibration performance. But the plunge friction inside the TCV joint will generate an unexpected axial force, which usually causes the vibration and noise. In this present work, a phenomenological TCV joint friction model was used in the numerical models of TCV joint based on ADAMS. This friction model incorporates the change of friction coefficient during the plunge-in and plunge-out motion and describes the rolling and slip friction situation in the TCV joint. So the friction at every parts of the TCV joint can be totally defined. The calculation results from traditional model and the simplified model were compared. The efficiency and accuracy of the simplified model was proved. Since then, the simplified TCV joint model can be used to predict generated axial force of TCV joint and vibration analysis. It will also make effect on the complex system analysis which contains the TCV joint

The Last Tear

Qiao Luo 한국콘텐츠학회 2018 ICCC International Digital Design Invitation Exhib Vol.2018 No.5

Space-Time Pattern of Ion Flow Under AC/DC Hybrid Overhead Lines and Its Application

Qiao, Ji,Zou, Jun,Zhang, Jiangong,Lu, Yao,Lee, Jaebok,Ju, Mun-No IEEE 2018 IEEE transactions on power delivery Vol.33 No.5

<P>Building HVdc and HVac transmission lines in the same corridor or even on the same tower is an attractive way to extend electricity transport capacity where getting the new right of way is difficult. The resulting hybrid lines produce a new corona performance, such as ground-level hybrid electric field and ion current density, which are quite different from those of pure ac or dc lines. In this paper, inherent space-time pattern and characteristics of the information propagation in Lagrangian description are presented for the ion transport problem, that is, the ion density at a certain point has a direct relationship with its drift time. Based on this, the theoretical explanation is provided for the decoupling algorithm, by which the ground-level dc component can be solved with the ac conductors assumed to be at zero potential and vice versa. The simulation results show that the sinusoidal ac field has negligible influence on the dc ion drift time from conductor surface to ground, whereas stationary electric field generated by the grounded ac lines has a dominant effect. Therefore, ac energization has a rather low impact on ground-level quantities and the simplification of grounded ac conductors is quite reasonable.</P>

Clonal Spread of Carbapenem Non-susceptible Acinetobacter baumannii in an Intensive Care Unit in a Teaching Hospital in China

Qiao Zhong,Weidong Xu,Yuanjian Wu,Hongxing Xu 대한진단검사의학회 2012 Annals of Laboratory Medicine Vol.32 No.6

Background: This study was aimed to investigate the genetic diversity and antibiotic resistance profile of the nosocomial infection agent Acinetobacter baumannii from a medical intensive care unit (ICU) in a teaching hospital in Suzhou, China. Methods: The genetic relationship among A. baumannii isolates in an ICU was investigated using multilocus sequence typing (MLST). The antibiotic resistance pattern was determined by performing an antibiotic susceptible test, which included an agar dilution method and an E-test method. Resistant determinants, e.g., carbapenemase genes, metallo-β- lactamases, and class 1 integron, were analyzed by specific PCR and DNA sequencing. Results: In the present study, 33 non-duplicate isolates were identified as 5 existing sequence types (STs) (ST92, ST75, ST112, ST145, and ST345) and 1 new sequence type STn, which has a G-A mutation at nt268 on ropD40 of ST251. These results reveal limited diversity in carbapenem non-susceptible A. baumannii (CNSAb) isolates in our ICU, which are comprised of only 2 distinct STs, with ST92 and ST75 clustering into a clonal complex (CC) 92. Most CNSAb isolates (94.4%, 17/18) harbored the OXA-23 gene, while no carbapenem-susceptible A. baumannii (CSAb) isolates harbored it. In addition, 66.7% (22/33) isolates were positive for class 1 integrase, and gene cassette analysis showed there are 3 gene arrays among them, i.e., aacA4-catB8-aadA1 (77.3%, 17/22), aacA4 (22.7%, 5/22), and aacC1-orfX-orfX’-aadA1 (4.5%, 1/22). Conclusions: When all these data are combined, the antibiotic resistance and wide distribution of CNSAb isolates in our ICU are probably caused by expansion of the CC92 clone. Background: This study was aimed to investigate the genetic diversity and antibiotic resistance profile of the nosocomial infection agent Acinetobacter baumannii from a medical intensive care unit (ICU) in a teaching hospital in Suzhou, China. Methods: The genetic relationship among A. baumannii isolates in an ICU was investigated using multilocus sequence typing (MLST). The antibiotic resistance pattern was determined by performing an antibiotic susceptible test, which included an agar dilution method and an E-test method. Resistant determinants, e.g., carbapenemase genes, metallo-β- lactamases, and class 1 integron, were analyzed by specific PCR and DNA sequencing. Results: In the present study, 33 non-duplicate isolates were identified as 5 existing sequence types (STs) (ST92, ST75, ST112, ST145, and ST345) and 1 new sequence type STn, which has a G-A mutation at nt268 on ropD40 of ST251. These results reveal limited diversity in carbapenem non-susceptible A. baumannii (CNSAb) isolates in our ICU, which are comprised of only 2 distinct STs, with ST92 and ST75 clustering into a clonal complex (CC) 92. Most CNSAb isolates (94.4%, 17/18) harbored the OXA-23 gene, while no carbapenem-susceptible A. baumannii (CSAb) isolates harbored it. In addition, 66.7% (22/33) isolates were positive for class 1 integrase, and gene cassette analysis showed there are 3 gene arrays among them, i.e., aacA4-catB8-aadA1 (77.3%, 17/22), aacA4 (22.7%, 5/22), and aacC1-orfX-orfX’-aadA1 (4.5%, 1/22). Conclusions: When all these data are combined, the antibiotic resistance and wide distribution of CNSAb isolates in our ICU are probably caused by expansion of the CC92 clone.

Modeling of {10-12}-{10-12} secondary twinning in pre-compressed Mg alloy AZ31

Qiao, H.,Guo, X.Q.,Hong, S.G.,Wu, P.D. Elsevier 2017 Journal of alloys and compounds Vol.725 No.-

<P><B>Abstract</B></P> <P>The deformation characteristics of rolled Mg alloy AZ31, which was previously compressed along the rolling direction and then re-compressed along the transverse direction, have been numerically investigated. Secondary/double twinning is allowed in the current EVPSC-TDT model, and {10-12}-{10-12} secondary twinning is found to play an important role in reproducing the experimental data. The deformation behavior of the pre-compressed materials associated with primary and secondary twining has been interpreted in terms of the predicted activities, twin volume fractions and texture evolutions. The {10-12}-{10-12} secondary twinning in the previously twinned region is most active for the 9% pre-compressed material while primary twinning within the residual un-twinned domain dominates twinning behavior for the 3% pre-compressed material.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The EVPSC model is first extended to simulate the {10-12}-{10-12} twinning. </LI> <LI> The deformation behavior of the pre-compressed materials has been interpreted. </LI> <LI> {10-12}-{10-12} twinning plays a key role in reproducing the experimental data. </LI> </UL> </P>