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.

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 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.

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.

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.

STABILITY OF MULTI–STAGE ACTIVE VIBRATION ISOLATION

Qiao Sun 한국소음진동공학회 2008 한국소음진동공학회 국제학술대회논문집 Vol.2008 No.7

Preparation of 2D/2D g-C3N4/Ti3C2 MXene composites by calcination synthesis method for visible light photocatalytic degradation of tetracycline

Qiao Le-Le,Zhang Feng-Jun,Kai Chun-Mei,Liu Chao,Wang Ying-Rui,Oh Won-Chun 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.5

In this work, an ultrathin 2D/2D g-C3N4/Ti3C2 heterojunction was synthesized by direct calcination of a mixture of urea and multilayer Ti3C2 for photocatalytic degradation of tetracycline. Among them, urea is the precursor for the generation of g-C3N4 and generates gas to peel the multilayer Ti3C2 into fewer layers while reacting, solving the problem of low yield for the preparation of fewer layers of Ti3C2. The experimental results of tetracycline degradation under visible light showed that pure g-C3N4 (UCN) exhibited weak photoactivity; however, its photocatalytic performance was enhanced when Ti3C2 was coupled with g-C3N4. The best sample (5TC) could degrade 90.1% of tetracycline within 30 min. After four cycles of stability test, the photocatalytic performance did not change significantly, indicating that the prepared 2D/2D g-C3N4/Ti3C2 heterojunction possesses strong photocatalytic performance along with good stability.

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>

Event-Triggered Robust Optimized Scheme with Impulse Control for DFIG Based Wind Turbine

Qiao Yanping,Guo Donghui 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5

This paper proposes an event-triggered impulse optimized control strategy for a model-free doubly-fed induction generator (DFIG) based wind turbine. Ignite from the Hamilton–Jacobi–Bellman (HJB) optimal control conditions, the stable and robust controls of DFIG under various uncertain conditions, covering generator parameters altering or grid perturbations, are realized. Bypassing the knotty model, a model-free local rotor current loop control model is proposed. Time-varying perturbations in the current (state) and voltage (control signal) of both single-cage and double-cage generators (SCIG and DCIG) are employed in simulating unstructured uncertainties to improve control performance. Unlike the traditional event-triggered optimization control, besides the general robust control conditions of the model-free DFIG, the accurate impulse compensation is synchronously derived with the adaptive neural network of the HJB optimization. Therefore, computation and transmission costs are minimized without affecting the system's stability, and adaptive impulse control is implemented for real-time tuning. Finally, the performance of the proposed controller is verified with a 1.5-MW DFIG model. Superior to proportional-integral resonant control and sliding mode control, better dynamic performance and anti-interference ability, and improved robustness under divergent uncertain conditions such as generator parameter changes or grid disturbances are comprehensively demonstrated.

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.