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Search Results: 1 - 10 of 83261 matches for " Lan Chen "
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Active ingredients of Plastrum Testudinis inhibit epidermal
Lan Chen
Zhong Xi Yi Jie He Xue Bao , 2011,
Abstract: Objective: To investigate the effects of active ingredients of Plastrum Testudinis (PT) on serum deprivation-induced apoptosis of epidermal stem cells (ESCs).Methods: ESCs were isolated from the back skin of fetal Sprague-Dawley rats with 2 weeks of gestational age and were divided into normal group (10% fetal bovine serum), control group (serum-deprived culture) and groups treated with serum deprivation plus active ingredients of PT, including ethyl acetate extract (2B), stearic acid ethyl ester (S6), tetradecanoic acid sterol ester (S8) and (+)-4-cholesten-3-one (S9). The vitality of ESCs after 24, 48 and 72 h of culture was measured with MTT method; apoptotic ESCs double-stained with Annexin V-FITC and propidium iodine were detected by flow cytometry (FCM); Bcl-2 and caspase-3 expressions were measured by Western blotting.Results: MTT results indicated that the vitality of ESCs in the active ingredients of PT groups at 48 h was increased compared with the control group and 2B had better effects than the others. FCM results indicated that 2B had the most significant anti-apoptotic effect compared with the control as well as S6, S8 and S9. Western blot results indicated that 2B, S6, S8 and S9 up-regulated the expression of Bcl-2 protein and down-regulated the expression of caspase-3 protein compared with the control.Conclusion: Ethyl acetate extract of Plastrum Testudinis inhibits epidermal stem cell apoptosis in serum-deprived culture by regulating the expressions of Bcl-2 and caspase-3 proteins and has a stronger anti-apoptotic effect than its constituents S6, S8 and S9.
The Reaction Sequence and Dielectric Properties of BaAl2Ti5O14 Ceramics  [PDF]
Xiaogang Yao, Wei Chen, Lan Luo
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24B008
Abstract: To investigate the correct reaction sequence of BaO-Al2O3-5TiO2 system, powders calcined at different temperatures are analyzed by x-ray diffraction. The results show that the source phase BaCO3 decomposes below 800°C, TiO2 and Al2O3 start to consume at 900 and 1100°C, respectively. BaTi4O9 phase appears at 1000°C while BaAl2Ti5O14 phase starts to reveal at 1200°C. As the temperature increases, the density, dielectric constant and quality factor of the BaAl2Ti5O14 ceramic increase and keep unchanged at 1350°C. The dielectric properties of BaAl2Ti5O14 ceramic sintered at 1350°C for 3h are: εr=35.8, Q×f=5130GHz, τf=-6.8ppm/°C.
The Impact of Global Financial Crisis on Health Status in the Chinese Mainland*  [PDF]
Chen Li, Yao Lan, Jiang Hong
Chinese Studies (ChnStd) , 2013, DOI: 10.4236/chnstd.2013.23023
Abstract: Nowadays, globalization increases the integration between countries, leading to the emergence of a global marketplace or a single world market. And, no country or region can develop in self-seclusion. The financial crisis is unprecedented because it comes at a time of radically increased interdependence. What is more, financial turmoil is contagious, moving rapidly from one country to another and spreading very quickly from one economic sector to many others. Since the reform and opening up, China has made remarkable economic achievements. Especially in the economic globalization trend, the financial sector has developed rapidly and its influence on economy is also growing fast. However, along with the rapid development of economy and the outbreak of financial crisis, economic factors play an important role in modern society. Due to the influence of the current global financial and economic crisis, efforts to reach health-related MDGs are confronted with daunting challenges. Public health departments of all countries are faced with increased demand for their services(Liu Zhenmin,2009), the risk of lower services quality, contraction of financial resources as well as a higher risk of a “brain drain” of health professionals. Hence, this paper aims to analyze the impact of the global recession on the health of people in the Chinese mainland and sum up a series of measures to ensure the steady growth of national economy and safeguard the social harmony and stability.
An Uncertain Programming Model for Competitive Logistics Distribution Center Location Problem  [PDF]
Bingyu Lan, Jin Peng, Lin Chen
American Journal of Operations Research (AJOR) , 2015, DOI: 10.4236/ajor.2015.56042
Abstract:

We employ uncertain programming to investigate the competitive logistics distribution center location problem in uncertain environment, in which the demands of customers and the setup costs of new distribution centers are uncertain variables. This research was studied with the assumption that customers patronize the nearest distribution center to satisfy their full demands. Within the framework of uncertainty theory, we construct the expected value model to maximize the expected profit of the new distribution center. In order to seek for the optimal solution, this model can be transformed into its deterministic form by taking advantage of the operational law of uncertain variables. Then we can use mathematical software to obtain the optimal location. In addition, a numerical example is presented to illustrate the effectiveness of the presented model.

Mechanism and Regulation of Nucleocytoplasmic Trafficking of Smad
Xiaochu Chen, Lan Xu
Cell & Bioscience , 2011, DOI: 10.1186/2045-3701-1-40
Abstract: Cytokines of the TGF-β superfamily are critically involved in embryonic development and adult tissue homeostasis [1]. Aberrant TGF-β signaling is a major contributing factor in the pathogenesis of diseases including cancer and tissue fibrosis [2]. Therefore, there has been tremendous interest in understanding how these extracellular factors control gene expression and cellular properties. Genetics identified cell surface TGF-β receptor kinases and intracellular Smad proteins as the critical components of the signaling mechanism [3]. The landmark finding came in the mid 1990s that revealed Smads as transcription factors and that their activities are turned on by direct phosphorylation by the TGF-β receptor kinases [4-7]. These Smads include Smad1, 2, 3, 5 and 8, which are commonly referred to as R-Smad (i.e. receptor-activated Smad). It was immediately realized that R-Smad activation upon TGF-β stimulation is accompanied by their cytoplasm-to-nucleus translocation [5,6]. In this way, the access of Smads to their large number of target genes is strictly signal-dependent, making Smad nuclear translocation an essential step in TGF-β signal transduction into the nucleus.The nuclear envelope restricts the movement of macromolecules between cytoplasm and nucleus, and the exchange of proteins or RNAs between the two compartments is exclusively through the nuclear pore complex (NPC) [8,9]. The prevailing model posits that for proteins to enter or exit the nucleus, they need carrier proteins called karyopherins [9,10]. The association of nuclear import cargoes with their karyopherins (i.e. importins) is disrupted by the small GTPase Ran in its GTP bound form [11]. On the other hand, for karyopherins specialized in nuclear export (i.e. exportins), its binding to cargoes is enhanced by RanGTP [12]. Interestingly Ran GTP is exclusively localized in the nucleus since the Ran GTP exchange factor (i.e. RCC1) is present only in the nucleus. This asymmetric distribution of RanGTP vs.
Hybrid spectrum arrangement and interference mitigation for coexistence between LTE macrocellular and femtocell networks
Yong Bai and Lan Chen
EURASIP Journal on Wireless Communications and Networking , 2013, DOI: 10.1186/1687-1499-2013-56
Abstract: When deploying two-tier LTE cellular networks with coexistence of macrocells and underlaid femtocells, the strategies of spectrum arrangement need to be investigated to efficiently utilize the scarce spectrum resource. Co-channel spectrumusage and dedicated-channel spectrum usage are two traditional strategies of spectrum arrangement. Nevertheless, there are pros and cons of them from the perspective of achievable network capacity in two-tier LTE network as they result in different amounts of available spectrum at each tier and disparate cross-tier interferences. To improve overall spectrum utilization, we propose a novel approach of spectrum arrangement, which is called hybrid spectrum arrangement, to take advantage of their merits. In our proposal, an underlaid femtocell can select its spectrum usage modeaccording to a criterion aiming to benefit both macrocell and femtocell in terms of achieved capacities. Consequently, the femtocells embedded in macrocell are self-organized as inner and outer femtocells, which operate in dedicated-channel spectrum usage and co-channel spectrum usage, respectively. Then, we examine distinct characteristics of cross-tier interferences in the context of hybrid spectrum arrangement and present corresponding schemes to mitigate the residual significant interferences. Analysis and system level simulation are given to validate the effectiveness of our proposed methods for two-tier LTE cellular network.
Combined Expression Trait Correlations and Expression Quantitative Trait Locus Mapping.
Lan,Chen,Flowers,Yandell
PLOS Genetics , 2006,
Abstract: Coordinated regulation of gene expression levels across a series of experimental conditions provides valuable information about the functions of correlated transcripts. The consideration of gene expression correlation over a time or tissue dimension has proved valuable in predicting gene function. Here, we consider correlations over a genetic dimension. In addition to identifying coregulated genes, the genetic dimension also supplies us with information about the genomic locations of putative regulatory loci. We calculated correlations among approximately 45,000 expression traits derived from 60 individuals in an F(2) sample segregating for obesity and diabetes. By combining the correlation results with linkage mapping information, we were able to identify regulatory networks, make functional predictions for uncharacterized genes, and characterize novel members of known pathways. We found evidence of coordinate regulation of 174 G protein-coupled receptor protein signaling pathway expression traits. Of the 174 traits, 50 had their major LOD peak within 10 cM of a locus on Chromosome 2, and 81 others had a secondary peak in this region. We also characterized a Riken cDNA clone that showed strong correlation with stearoyl-CoA desaturase 1 expression. Experimental validation confirmed that this clone is involved in the regulation of lipid metabolism. We conclude that trait correlation combined with linkage mapping can reveal regulatory networks that would otherwise be missed if we studied only mRNA traits with statistically significant linkages in this small cross. The combined analysis is more sensitive compared with linkage mapping alone.
A New Method For Industrial Production of 2,3-Butanediol  [PDF]
Lan Ge, Xiaomin Wu, Jianwen Chen, Jialin Wu
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2011, DOI: 10.4236/jbnb.2011.23041
Abstract: A new industrial production method of 2, 3-butanediol is discussed in this paper. C2-4 bio-polyol is prepared by combining biological fermentation and chemical cleavage, with corn starch as raw material. In this industrial method, high purity 2,3-butanediol can be obtained after distillation and purification. Low production cost of this method provides an effective support for 2, 3-butanediol large-scaled application.
Safety Distance Determination for 500 kV AC Transmission Line’s Helicopter Inspection  [PDF]
Shuwei Wan, Xingming Bian, Lan Chen, Liming Wang, Zhicheng Guan
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B219
Abstract: As an efficient and advanced line inspection method, helicopter line patrol is gradually more and more used in transmission lines inspection, promoting the elaborate operation of transmission lines and reducing the management cost. However, as a 'floating-potential conductor' near to a high-voltage transmission line, the helicopter would be at a high electric field region; and bring security risk to equipment and operating personnel. In this paper, the electric field strength near the cabin at locations of different distance from transmission lines is investigated by calculation, and the field in the helicopter cabin is also calculated with finite element method (FEM). The result indicates that the potential difference becomes higher with the decrease of the distance between the helicopter and transmission line. Considering the discharge energy and the guarantee of the persons’ safety, the safety distance is determined as d≥15 m.
Hexavalent Chromium Removal from Water Using Heat-Acid Activated Red Mud  [PDF]
Min Ma, Yifeng Lu, Rongzhi Chen, Lan Ma, Ying Wang
Open Journal of Applied Sciences (OJAppS) , 2014, DOI: 10.4236/ojapps.2014.45027
Abstract: This study investigated the heat-acid activated red mud used for hexavalent chromium (Cr6+) removal from aqueous solution. The results showed that the heat-acid activated red mud enhanced hexavalent chromium removal capacity from 0.003 to 0.015 mg·g﹣1. Adsorption experiments were conducted as a function of adsorbent dosage, contact time, pH and reaction temperature. The removal efficiency was found to increase gradually when solution pH decreased and maximum removal was achieved at pH 2. The physico-chemical characteristics of heat-acid activated red mud were studied by using instrumental technique like Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and X-ray fluorescence spectrometry (XRF). The experimental data fitted well to Langmuir isotherm model. Thermodynamic parameters indicated the adsorption process was exothermic reaction. The cost-effective performance and, simple operation suggest the heat-acid activated red mud can be taken as a promising sorbents for removal of Cr6+ from wastewater.
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