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Open access

Haiyan Wang, Lei Zhang, Shuiyuan Cheng, Fan Feng and Wei Liu

Open access

Qijie Xu, Lei Zhang, Wenzhong Shi and Yuanchen Cui

Catalytic performances of cross-linking humic acids supported Pd/Ni bimetallic catalyst for heck reaction

The cross-linking humic acids (CL-HAs), epichlorohydrin as the cross-linking reagent and the supported Pd/Ni bimetallic catalysts (CL-HAs-Pd/Ni) were prepared and characterized by IR, AAS, XPS, TEM. The effects of reaction time, temperature, base, solvent and the amount of catalyst on the properties of the catalyst were studied. These catalysts could catalyze the Heck reaction of aryl halides and substituted aryl halides with acrylic acids or styrene successfully; the yields were all above 95%.

Open access

Kun Lei, Hongfang Ma, Haitao Zhang, Weiyong Ying and Dingye Fang

Abstract

The present work was a study on global reaction rate of methanol synthesis. We measured experimentally the global reaction rate in the internal recycle gradientless reactor over catalyst SC309. The diffusion-reaction model of methanol synthesis was suggested. For model we chose the hydrogenation of CO and CO2 as key reaction. CO and CO2 were key components in our model. The internal diffusion effectiveness factors of CO and CO2 in the catalyst were calculated by the numerical integration. A comparison with the experiment showed that all the absolute values of the relative error were less than 10%. The simulation results showed that decreasing reaction temperature and catalyst diameter were conducive to reduce the influence of the internal diffusion on the methanol synthesis.

Open access

Xia Cuijuan, Liu Wei and Zhang Lei

Abstract

Linked data is becoming a mature technology as a lightweight realization of the Semantic Web, as well as a way of facilitating knowledge reorganization and discovery. As a use case and start point, based on linked data technology, a genealogy knowledge service platform was implemented by the Shanghai Library for providing knowledge discovery and open data services. This article explains the design and development of the Genealogy Knowledge Service Platform, describes the method and process of the implementation, and introduces four examples of how the platform helps users to discover questions, raise questions, and solve questions for their research, to explain how Linked Data can be used in Digital Humanities.

Open access

Lei Feng, Xiaoping Zhang, Hui Hua, Liying Qiu, Lianfen Zhang and Zhongwei Lv

Abstract

Background: Study of antiangiogenic drugs is one of the cutting-edge fields in new antitumor drug development. However, system studies on Vaccaria segetalis extract as an inhibitor of tumor-induced neovascularization have not been published yet. In the current study, we performed a preliminary investigation of the antiangiogenic effect of Vaccaria segetalis extract on angiogenesis.

Objective: We studied the inhibitory effect of Vaccaria segetalis extract on neovascularization.

Methods: The effects of Vaccaria segetalis extract on in vitro proliferation, migration, and tube formation of human mammary endothelial cells (HMECs) were determined by 3 - (4,5) - dimethylthiahiazo (-z-y1) - 3, 5 -diphenytetrazoliumromide (MTT) assay and Matrigel plug assay. The antiangiogenic effect of Vaccaria segetalis extract was observed on the chick chorioallantoic-membrane (CAM) angiogenesis model. The CD31 expression on HMECs was detected by immunohistochemical staining. The therapeutic effect of Vaccaria segetalis extract on the metastasis of Lewis lung cancer was also observed in the mouse model.

Results: The proliferation and migration of human mammary epithelial cells (HMECs) were inhibited significantly by Vaccaria segetalis extract in a dose-dependent manner (IC50 = 50 μg/mL). Angiogenesis was also inhibited in the Matrigel-plug mouse model and the chick chorioallantoic-membrane model. The Vaccaria segetalis extract treatment reduced the expression of CD31 in HMECs and inhibited the growth and metastasis of Lewis lung carcinoma cells in the mouse model.

Conclusion: The Vaccaria segetalis extract, which can obviously inhibit angiogenesis, could be developed as a promising new antiangiogenic drug.

Open access

Tu Hong-Sheng, Tu Shi-Hao, Zhang Cun, Zhang Lei and Zhang Xiao-Gang

Abstract

A steep seam similar simulation system was developed based on the geological conditions of a steep coal seam in the Xintie Coal Mine. Basing on similar simulation, together with theoretical analysis and field measurement, an in-depth study was conducted to characterize the fracture and stability of the roof of steep working face and calculate the width of the region backfilled with gangue in the goaf. The results showed that, as mining progressed, the immediate roof of the steep face fell upon the goaf and backfilled its lower part due to gravity. As a result, the roof in the lower part had higher stability than the roof in the upper part of the working face. The deformation and fracture of main roof mainly occurred in the upper part of the working face; the fractured main roof then formed a “voussoir beam” structure in the strata’s dip direction, which was subjected to the slip- and deformation-induced instability. The stability analysis indicated that, when the dip angle increased, the rock masses had greater capacity to withstand slip-induced instability but smaller capacity to withstand deformation-induced instability. Finally, the field measurement of the forces exerted on the hydraulic supports proved the characteristics of the roof’s behaviors during the mining of a steep seam.

Open access

Zhitao Xiao, Lei Pei, Fang Zhang, Ying Sun, Lei Geng, Jun Wu and Jun Tong

Abstract

In this paper, a new method based on phase congruency is proposed to measure pitch lengths and surface braiding angles of two-dimensional biaxial braided composite preforms. Lab space transform and BM3D (block-matching and 3D filter) are used first to preprocess the original acquired images. A corner detection algorithm based on phase congruency is then proposed to detect the corners of the preprocessed images. Pitch lengths and surface braiding angles are finally measured based on the detected corner maps. Experimental results show that our method achieves the automatic measurement of pitch lengths and the surface braiding angles of biaxial braided composite preforms with high accuracy.

Open access

Lei Zhang, Zhiwei Ye, Jun Tang, Dingyi Hao and Cun Zhang

Abstract

As a kind of associated geological gas, coalbed methane (CBM) is mainly adsorbed in the coal seam. The coal-methane adsorption phenomenon can be described by Langmuir monolayer adsorptio n model, BET multilayer adsorption model and the Theory of Volume Filling of Micropore (TVFM), whereas the binary gas adsorption phenomenon can be described by the extended Langmuir Model. For the CBM in the low permeability coal seam, the amount of gas released by direct drainage is relatively limited, which cannot eliminate the gas explosion and outburst hazards. Gas injection is an effective method to promote methane drainage. In this paper, the free desorption and nitrogen injection displacement experiments are comparatively analyzed, which allows verifying the effectiveness of nitrogen injection’s enhancement to gas drainage. The experiment of injecting nitrogen gas into the coal body shows that the coal fracture can be maintained or expanded by the injected gas pressure so that more methane can be released. The nitrogen injection has a higher time efficiency than that of free desorption as well. The displacement ratio of N2/CH4 is in the range of 1-3. Both the injection pressure and confining pressure affect the displacement ratio. The analysis of the desorbed gas components shows that the relationship between the methane component and gas flooding time is an “inverted S” shape curve, and the appropriate time for the methane collection can be inferred by the time interval of the rapid decline of the curve.

Open access

Dansheng Lei, Guanhui Zhang, Jian Fan, Jing Yu and Shaoqing Hu

Abstract

Background: Ficolins are lectins that have been demonstrated to play an important role in innate immune response in a variety of diseases. Mycobacterium tuberculosis (M.tb) infection can trigger a series of changes in the host. However, the role of ficolin in tuberculosis is still unclear.

Objective: We investigated the expression of ficolin in peripheral blood mononuclear cell (PBMC) in TB patients and healthy control.

Methods: Using semi-quantitative RT-PCR, western blotting, and flow cytometry, we compared the expression of M-ficolin, L-ficolin, and H-ficolin in the peripheral blood mononuclear cell (PBMC), purified monocytes, and cultured dendritic cells of TB patients with healthy volunteers as controls.

Results: M-ficolin expression in PBMC was significantly lower at both mRNA and protein levels in TB patients as compared to healthy controls. The lower M-ficolin level in TB patient PBMCs may be attributed to its lower level in monocytes. The expression levels of H-ficolin and L-ficolin in both healthy controls and TB patients were very low and they had no significant differences between the two groups.

Conclusions: Compared to healthy controls, M-ficolin expression is significantly lower in TB patients. Measurement of M-ficolin may be a potential auxiliary tool to diagnose TB infection.