Innovation and organizational performance: A perspective among Chinese enterprises.

The influence of innovation on the performance of Chinese enterprises still remains inconclusive in the literature of innovation management. The aim of this research therefore is to examine the link between innovation and performance of Chinese enterprises, and explore the influence of sentiment expressed by investors in this relationship. The data for our study are drawn from 3,500 Chinese listed firms, operating within the periods, 2009-2017. Panel autoregressive models (fixed and random effects) are employed in our empirical analyses. We further performed Hausman tests in order to ascertain which of the models is more suitable for our dataset. Results from the analysis show that innovation significantly influences the performance of Chinese enterprises and it is moderated by sentiment expressed by investors. Specifically, it is found that Chinese enterprises tend to be innovative as feedback to sentiment expressed by investors and this consequently results in higher performance.

Accuracy analysis of an orthogonally arranged four-camera 3D digital image correlation system.

To reduce the uncertainty region of a three-dimensional (3D) position, a four-camera 3D digital image correlation (3D-DIC) system was built by orthogonally arranging two sets of two-camera DIC systems. The theoretical model proposed herein revealed the relationship between 3D coordinates and system parameters and the propagation of the matching error to the position error. Numerical simulation and experiment were conducted to verify the theory. The simulation and experimental results indicated that the 3D position error of the four-camera system was smaller than that of the two-camera DIC system. The present contribution proves the feasibility of using four-camera DIC systems to improve measurement accuracy.

SERPINA3K plays antioxidant roles in cultured pterygial epithelial cells through regulating ROS system.

We recently demonstrated that SERPINA3K, a serine proteinase inhibitor, has antioxidant activity in the cornea. Here we investigated the antioxidant effects of SERPINA3K on the pterygial, which is partially caused by oxidative stress in pathogenesis. The head part of primary pterygial tissue was dissected and then cultured in keratinocyte serum-free defined medium (KSFM). The cultured pterygial epithelial cells (PECs) were treated with SERPINA3K. The cell proliferation and migration of PECs were measured and analyzed. Western blot and quantitative real-time polymerase chain reaction (PCR) assay were performed. It showed that SERPINA3K significantly suppressed the cell proliferation of PECs in a concentration-dependent manner, compared with cultured human conjunctival epithelial cells. SERPINA3K also inhibited the cell migration of PECs. Towards its underlying mechanism, SERPINA3K had antioxidant activities on the PECs by significantly inhibiting NADPH oxidase 4 (NOX4), which is an important enzyme of ROS generation, and by elevating the levels of key antioxidant factors of ROS: such as NAD(P)H dehydrogenase (quinone 1) (NQO1), NF-E2-related factor-2 (NRF2) and superoxide dismutases (SOD2). Meanwhile, SERPINA3K down-regulated the key effectors of Wnt signaling pathway: ß-catenin, nonphospho-ß-catenin, and low-density lipoprotein receptor-related protein 6 (LRP6). We provided novel evidence that SERPINA3K had inhibitory effects on pterygium and SERPINA3K played antioxidant role via regulating the ROS system and antioxidants.

Serine Proteinase Inhibitor SERPINA3K Suppresses Corneal Neovascularization via Inhibiting Wnt Signaling and VEGF.

Purpose: To evaluate the anti-neovascularization effects and investigate the possible mechanisms of SERPINA3K, a member of serine proteinase inhibitor family, using a specific rat model of suture-induced corneal neovascularization. Methods: A rat corneal suture model was set up and SERPINA3K was topically administered three times daily for 7 days. The clinical indications were evaluated on day 2, 5 and 7, including area of neovascularization and inflammation index. The eyeballs were collected after day 7 and the following examinations were performed: histological investigation, immunostaining, western blot and quantitative real-time polymerase chain reaction (PCR) assay. Wnt3a, a Wnt pathway ligand, was added to cultured Human Umbilical Vein Endothelial Cells (HUVEC), followed by detecting cell migration and western blot. Meanwhile, an in vitro VEGF165-stimulated HUVEC model was applied and the following measurements were conducted: cell proliferation, cell migration and tube formation. Results: SERPINA3K significantly suppressed corneal neovascularization and inhibited corneal inflammation. SERPINA3K downregulated the levels of ß-catenin, non-pi-ß-catenin and transcription factor 4 (TCF4), but upregulated the level of pi-ß-catenin of the corneas induced by suture. SERPINA3K also decreased the gene expression and protein level of VEGF. Meanwhile, induction of Wnt3a increased the cell migration, activated the Wnt signaling and upregulated VEGF in cultured HUVEC, which were antagonized by SERPINA3K. In addition, SERPINA3K significantly inhibited VEGF165-induced cell proliferation and migration of HUVEC, SERPINA3K also specifically suppressed the VEGF165-induced tube formation of HUVEC. Conclusions: SERPINA3K has therapeutic potential for corneal neovascularization. The underlying mechanism may be through inhibiting Wnt signaling pathway and VEGF.

SERPINA3K protects against oxidative stress via modulating ROS generation/degradation and KEAP1-NRF2 pathway in the corneal epithelium.

PURPOSE: We recently reported that SERPINA3K (SA3K), a member of the serine proteinase inhibitor (SERPIN) family, has antiangiogenic and anti-inflammatory activities. Here we investigated the antioxidant effects of SA3K in the corneal epithelium and the mechanism underlying its action. METHODS: We established the oxidative stress models induced by hydrogen peroxide (H2O2) in cultured human corneal epithelial (HCE) cells and in rat corneal epithelium in vivo. Cell viability, flow cytometry, and TUNEL analysis were conducted to detect viable cells and cell death; reactive oxygen species (ROS) and 3-Nitrotyrosine fluorescent assay was applied to measure ROS levels. Activity assay, immunostaining, Western blot, and quantitative RT-PCR were performed to analyze the factors of the ROS generation/degradation system and pathway. RESULTS: SA3K protected the HCE cells from H2O2-induced oxidative stress in a dose- and time-dependent manner. SA3K also significantly reduced the production of ROS. Regarding the mechanism underlying these effects, SA3K downregulated ROS generation by inhibiting NOX4 and upregulated ROS degradation by increasing the activity of superoxide dismutases and catalase. Furthermore, H2O2 induced activation of the Kelch-like ECH-associated protein 1 (KEAP1)/NF-E2-related factor-2 (NRF2) pathway, while SA3K inhibited H2O2-induced activation of KEAP1 and NRF2 and their downstream factors, including NAD(P)H quinone oxidoreductase and glutathione S-transferase. In the H2O2-induced rat corneal epithelium, SA3K alleviated the oxidative stress and downregulated NOX4 and NRF2. CONCLUSIONS: Collectively, SA3K protects against oxidative stress by targeting the ROS generation/degradation system and modulating the KEAP1-NRF2 signaling pathway.