Do Foreign Investors Monitor Managers in Merger and Acquisition? Evidence from China

Chao Xu,Xiaofang Zhao,Hao Yang,Shiqing Li 한국증권학회 2022 Asia-Pacific Journal of Financial Studies Vol.51 No.1

Using foreign investors’ shareholding to proxy for foreign investors’ monitoring effect in the Chinese stock market, we find that those acquirers exhibit higher announcement returns with higher shareholding, and this effect is stronger when acquirers are private firms. We provide price efficiency and corporate governance channels through which foreign investors play a monitoring role in mergers and acquisitions. Finally, foreign investors decrease the likelihood that managers will conduct mergers in the future and significantly improve long-run performance. Our study provides new insights into the real effects of foreign investors on acquisition performance and the economy.

Effects of strain on the optical and magnetic properties of Ce-doped ZnO

Zhenchao Xu,Qingyu Hou,Feng Guo,Xiaofang Jia,Cong Li,Wenling Li 한국물리학회 2018 Current Applied Physics Vol.18 No.12

The magnetic and optical properties of Ce-doped ZnO systems have been widely demonstrated, but the effects of different strains of Ce-doped ZnO systems remain unclear. To solve these problems, this study identified the effects of biaxial strain on the electronic structure, absorption spectrum, and magnetic properties of Ce-doped ZnO systems by using a generalized gradient approximation + U (GGA + U) method with plane wave pseudopotential. Under unstrained conditions, the formation energy decreased, the system became stable, and the doping process became easy with the increase in the distances between two Ce atoms. The band gap of the systems with different strains became narrower than that of undoped ZnO without strain, and the absorption spectra showed a red shift. The band gap narrowed, and the red shift became weak with the increase of compressive strain. By contrast, the band gap widened, and the red shift became significant with the increase of tensile strain. The red shift was significant when the tensile strain was 3%. The systems with −1%, 0%, and 1% strains were ferromagnetic. For the first time, the magnetic moment of the system with −1% strain was found to be the largest, and the system showed the greatest beneficial value for diluted magnetic semiconductors. The systems with −3%, −2%, 2%, and 3% strains were non-magnetic, and they had no value for diluted magnetic semiconductors. The ferromagnetism of the system with −1% strain was mainly caused by the hybrid coupling of Ce-4f, Ce-5d, and O-2p orbits. This finding was consistent with Zener's Ruderman–Kittel–Kasuya–Yosida theory. The results can serve as a reference for the design and preparation of new diluted magnetic semiconductors and optical functional materials.

SOME CLASSES OF REPEATED-ROOT CONSTACYCLIC CODES OVER Fpm + uFpm + u2Fpm

Xiusheng Liu,Xiaofang Xu 대한수학회 2014 대한수학회지 Vol.51 No.4

Constacyclic codes of length ps over R = Fpm + uFpm + u2Fpm are precisely the ideals of the ring R[x]/(xps −1). In this paper, we investigate constacyclic codes of length ps over R. The units of the ring R are of the forms γ, α+uβ, α+uβ +u2γ and α+u2γ, where α, β and γ are nonzero elements of Fpm . We obtain the structures and Hamming distances of all (α+uβ)-constacyclic codes and (α+uβ+u2γ)-constacyclic codes of length ps over R. Furthermore, we classify all cyclic codes of length ps over R, and by using the ring isomorphism we characterize γ-constacyclic codes of length ps over R.

SOME CLASSES OF REPEATED-ROOT CONSTACYCLIC CODES OVER _p_m+u_p_m+u²_p_m

Liu, Xiusheng,Xu, Xiaofang Korean Mathematical Society 2014 대한수학회지 Vol.51 No.4

Constacyclic codes of length $p^s$ over $R=\mathbb{F}_{p^m}+u\mathbb{F}_{p^m}+u^2\mathbb{F}_{p^m}$ are precisely the ideals of the ring $\frac{R[x]}{<x^{p^s}-1>}$. In this paper, we investigate constacyclic codes of length $p^s$ over R. The units of the ring R are of the forms ${\gamma}$, ${\alpha}+u{\beta}$, ${\alpha}+u{\beta}+u^2{\gamma}$ and ${\alpha}+u^2{\gamma}$, where ${\alpha}$, ${\beta}$ and ${\gamma}$ are nonzero elements of $\mathbb{F}_{p^m}$. We obtain the structures and Hamming distances of all (${\alpha}+u{\beta}$)-constacyclic codes and (${\alpha}+u{\beta}+u^2{\gamma}$)-constacyclic codes of length $p^s$ over R. Furthermore, we classify all cyclic codes of length $p^s$ over R, and by using the ring isomorphism we characterize ${\gamma}$-constacyclic codes of length $p^s$ over R.

RhGLP-1 (7-36) protects diabetic rats against cerebral ischemia-reperfusion injury via up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD

Yi Fang,Xiaofang Liu,Libo Zhao,Zhongna Wei,Daoli Jiang,Hua Shao,Yannan Zang,Jia Xu,Qian Wang,Yang Liu,Ye Peng,Xiaoxing Yin 대한약리학회 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.5

The present study aimed to explore the neuroprotective effect and possible mechanisms of rhGLP-1 (7-36) against transient ischemia/reperfusion injuries induced by middle cerebral artery occlusion (MCAO) in type 2 diabetic rats. First, diabetic rats were established by a combination of a high-fat diet and low-dose streptozotocin (STZ) (30 mg/kg, intraperitoneally). Second, they were subjected to MCAO for 2 h, then treated with rhGLP-1 (7-36) (10, 20, 40 μg/kg i.p.) at the same time of reperfusion. In the following 3 days, they were injected with rhGLP-1 (7- 36) at the same dose and route for three times each day. After 72 h, hypoglycemic effects were assessed by blood glucose changes, and neuroprotective effects were evaluated by neurological deficits, infarct volume and histomorphology. Mechanisms were investigated by detecting the distribution and expression of the nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) in ischemic brain tissue, the levels of phospho-PI3 kinase (PI3K)/PI3K ratio and heme-oxygenase-1 (HO-l), as well as the activities of superoxide dismutase (SOD) and the contents of malondialdehyde (MDA). Our results showed that rhGLP-1 (7-36) significantly reduced blood glucose and infarction volume, alleviated neurological deficits, enhanced the density of surviving neurons and vascular proliferation. The nuclear positive cells ratio and expression of Nrf2, the levels of P-PI3K/PI3K ratio and HO-l increased, the activities of SOD increased and the contents of MDA decreased. The current results indicated the protective effect of rhGLP-1 (7-36) in diabetic rats following MCAO/R that may be concerned with reducing blood glucose, up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD.

Lotus-Like Nano-Architectures Constructed from Self-Assembled Micelles via Hierarchical Assembly

Rongli Zhang,Xiaoxia Fan,Xiaofang Xu,Jingjing Lv,Zhenzhen Jin,Hui Hao,Cuige Zhang 한국고분자학회 2018 Macromolecular Research Vol.26 No.1

Dopamine modified γ-polyglutamic acid (γ-PGA-DA) copolymer and melamine (Mel) can self-assemble into Mel/γ-PGA-DA micelles via weak intermolecular interactions in aqueous solution containing small amount of methanol. When Mel/γ-PGA-DA micellar solution was cast on the surface of formvar stabilized with carbon support films, the lotus-like nano-architectures were formed on the surface of substrate via hierarchical assembly of micelles. The size of lotus-like nanoarchitectures was approximately 200 nm×500 nm. The possible driving forces for hierarchical assembly of micelles were the solution fluid and interaction between micelles. The hierarchical assembly of micelles was similar to the fractal aggregation of inorganic particles and a possible reason was discussed.

Contrast Induced Nephropathy and 2-Year Outcomes of Iso-Osmolar Compared with Low-Osmolar Contrast Media after Elective Percutaneous Coronary Intervention

Mengyang Du,Lin Jiang,Xiaofang Tang,Zhan Gao,Bo Xu,Jinqing Yuan 대한심장학회 2021 Korean Circulation Journal Vol.51 No.2

Background and Objectives: This study investigated the relative incidence of contrast induced nephropathy (CIN) and long-term outcomes between iso-osmolar contrast media (IOCM) and low-osmolar contrast media (LOCM) undergoing elective percutaneous coronary intervention (PCI). Methods: A total of 9,431 patients receiving elective PCI were enrolled in the cohort. The patients were divided into IOCM group and LOCM group. Propensity score matching (PSM) was applied to minimize the selection bias between groups. Results: The multivariate analysis showed that the use of IOCM compared with LOCM did not affect the CIN incidence (odds ratio [OR], 0.912; 95% confidence interval [CI], 0.576–1.446; p=0.696). After PSM, the incidence of CIN was 1.5% and 4.0% in IOCM group (n=979) and LOCM group (n=979), respectively, p=0.001. IOCM significantly reduced the incidence of CIN compared with LOCM (OR, 0.393; 95% CI, 0.214–0.722; p=0.003). After 2 years of follow-up, the all-cause mortality was higher in IOCM group than LOCM group (2.1% vs. 0.9%, p<0.001). Cox regression analysis showed IOCM was not independent risk factor of 2-years all-cause mortality (OR, 0.849; 95% CI, 0.510–1.412; p=0.528). After PSM, the difference of all-cause death between groups disappeared (1.7% vs. 1.9%, p=0.739). Cox regression analysis showed that the use of IOCM compared with LOCM did not affect the incidence of 2-year all-cause mortality (OR, 1.037; 95% CI, 0.534–2.014; p=0.915). Conclusions: Compared with LOCM, IOCM significantly reduced the incidence of CIN after elective PCI, but had no significant effect on 2-year all-cause mortality.

Ferroptosis: A Novel Anti-tumor Action for Cisplatin

Jipeng Guo,Bingfei Xu,Qi Han,Hongxia Zhou,Yun Xia,Chongwen Gong,Xiaofang Dai,Zhenyu Li,Gang Wu 대한암학회 2018 Cancer Research and Treatment Vol.50 No.2

Purpose Ferroptosis is a new mode of regulated cell death, which is completely distinct from other cell death modes based on morphological, biochemical, and genetic criteria. This study evaluated the therapeutic role of ferroptosis in classic chemotherapy drugs, including the underlying mechanism. Materials and Methods Cell viability was detected by using the methylthiazoltetrazlium dye uptake method. RNAi was used to knockout iron-responsive element binding protein 2, and polymerase chain reaction, western blot was used to evaluate the efficiency. Intracellular reduced glutathione level and glutathione peroxidases activity were determined by related assay kit. Intracellular reactive oxygen species levels were determined by flow cytometry. Electron microscopy was used to observe ultrastructure changes in cell. Results Among five chemotherapeutic drugs screened in this study, cisplatin was found to be an inducer for both ferroptosis and apoptosis in A549 and HCT116 cells. The depletion of reduced glutathione caused by cisplatin and the inactivation of glutathione peroxidase played the vital role in the underlying mechanism. Besides, combination therapy of cisplatin and erastin showed significant synergistic effect on their anti-tumor activity. Conclusion Ferroptosis had great potential to become a new approach in anti-tumor therapies and make up for some classic drugs, which open up a new way for their utility in clinic.

RhGLP-1 (7-36) protects diabetic rats against cerebral ischemia-reperfusion injury via up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD

Fang, Yi,Liu, Xiaofang,Zhao, Libo,Wei, Zhongna,Jiang, Daoli,Shao, Hua,Zang, Yannan,Xu, Jia,Wang, Qian,Liu, Yang,Peng, Ye,Yin, Xiaoxing The Korean Society of Pharmacology 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.5

The present study aimed to explore the neuroprotective effect and possible mechanisms of rhGLP-1 (7-36) against transient ischemia/reperfusion injuries induced by middle cerebral artery occlusion (MCAO) in type 2 diabetic rats. First, diabetic rats were established by a combination of a high-fat diet and low-dose streptozotocin (STZ) (30 mg/kg, intraperitoneally). Second, they were subjected to MCAO for 2 h, then treated with rhGLP-1 (7-36) (10, 20, $40{\mu}g/kg$ i.p.) at the same time of reperfusion. In the following 3 days, they were injected with rhGLP-1 (7-36) at the same dose and route for three times each day. After 72 h, hypoglycemic effects were assessed by blood glucose changes, and neuroprotective effects were evaluated by neurological deficits, infarct volume and histomorphology. Mechanisms were investigated by detecting the distribution and expression of the nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) in ischemic brain tissue, the levels of phospho-PI3 kinase (PI3K)/PI3K ratio and heme-oxygenase-1 (HO-l), as well as the activities of superoxide dismutase (SOD) and the contents of malondialdehyde (MDA). Our results showed that rhGLP-1 (7-36) significantly reduced blood glucose and infarction volume, alleviated neurological deficits, enhanced the density of surviving neurons and vascular proliferation. The nuclear positive cells ratio and expression of Nrf2, the levels of P-PI3K/PI3K ratio and HO-l increased, the activities of SOD increased and the contents of MDA decreased. The current results indicated the protective effect of rhGLP-1 (7-36) in diabetic rats following MCAO/R that may be concerned with reducing blood glucose, up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD.

Promoting effect of Mn and Ti on the structure and performance of Co3O4 catalysts for oxidation of dibromomethane

Jian Mei,Zan Qu,Songjian Zhao,Xiaofang Hu,Haomiao Xu,Naiqiang Yan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

Co3O4 catalysts modified with Mn and Ti, prepared by co-precipitation method, were used for catalytic oxidation of dibromomethane (CH2Br2), a model molecule for brominated volatile organic compounds (BVOCs). Addition of Ti or Ti + Mn distorted the crystal structure and led to the formation of a Co–O–Ti solid solution. The addition of Mn further enhanced the surface acidity and redox ability of the catalysts. Co–Mn–Ti exhibited the highest activity with a T90 of approximately 234 °C and the highest selectivity to CO2 at low temperatures. Additionally, Co–Mn–Ti showed good stability for at least 30 h at 500 ppm CH2Br2, 0 or 2 vol% H2O, 0 or 500 ppm p-xylene (PX), and 10% O2 at a gas hourly space velocity of 60,000 h−1, and the final products were COx, Br2, and HBr, without the formation of other Br-containing organic byproducts. This high catalytic activity was attributed to its high specific area, high surface acidity, and strong redox property. Furthermore, the synergetic effect of Co, Mn, and Ti made it superior for CH2Br2 oxidation. A plausible reaction mechanism for CH2Br2 oxidation over Co–Mn–Ti catalysts was proposed based on the analysis of the products and in situ diffuse-reflectance infrared Fourier transform spectroscopy results.