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Search Results: 1 - 10 of 62739 matches for " Sun Jun "
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Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases Are Essential for the Inflammatory Response in Cancer Cells
Jun Sun
Journal of Signal Transduction , 2010, DOI: 10.1155/2010/985132
Abstract: Inflammation plays a critical role in the development of cancer. Matrix Metalloproteinase (MMP) functions in the remodeling of the extracellular matrix that is integral for many normal and pathological processes such as morphogenesis, angiogenesis, tissue repair, and tumor invasion. The tissue inhibitor of metalloproteinases (TIMPs) family regulates the activity of multifunctional metalloproteinases. In this paper, we discuss the role and mechanism of MMP and TIMP in regulating inflammation responses in solid tumors. We discuss the mechanism of MMP and inflammation in melanoma, colon cancer, breast cancer, and prostate cancer. We highlight the roles of the TIMP-2 in modulating the proinflammatory NF- B pathway in melanoma and lung caner cells. Based on the molecular mechanisms of TIMPs and MMPs in inflammation and cancer, we can design new strategies for cancer therapy. 1. Introduction MMPs belong to a family of structurally related proteolytic enzymes that mediate degradation of the extracellular matrix and the basement of membranes [1–3]. High levels of MMP activity have been linked to tumor growth, invasion, and angiogenesis inflammation and may even work in a nonproteolytic manner [4, 5]. The tissue inhibitor of metalloproteinases family, including TIMP-1, 2, 3, and 4, regulates the activity of multifunctional metalloproteinases [6, 7]. Among TIMP members, TIMP-2 is most frequently investigated because it is a unique member of the TIMP family and involved in cancer progression and metastasis. Recent studies have begun to unravel molecular pathways linking inflammation and cancer [8, 9]. Inflammatory conditions can initiate or promote oncogenic transformation and genetic and epigenetic changes in malignant cells. An inflammatory microenvironment further supports tumor progression [10–12]. Cancer-associated inflammation is marked by the presence of specific inflammatory cells and inflammatory mediators, including cytokines and chemokines. Nuclear factor- B (NF- B) transcription factor plays an essential role in innate and adaptive immune responses, cell proliferation, apoptosis, and tumorigenesis [13–15]. Constitutive activation of NF- B has been directly implicated in tumorigenesis of various cancer types [16–18]. Recent evidence also suggests a crucial role for signal transducer and activator of transcription (STAT) family in selectively inducing and maintaining a procarcinogenic inflammatory microenvironment, both at the initiation of malignant transformation and during cancer progression [11]. The targeting of inflammatory mediators (chemokines
Enteric Bacteria and Cancer Stem Cells
Jun Sun
Cancers , 2011, DOI: 10.3390/cancers3010285
Abstract: Intestinal bacteria can contribute to cell proliferation and cancer development, particularly in chronic infectious diseases in which bacteria and/or bacterial components might interfere with cell function. The number of microbial cells within the gut lumen is estimated to be 100 trillion, which is about 10-times larger than the number of eukaryotic cells in the human body. Because of the complexity of the gut flora, identifying the specific microbial agents related to human diseases remains challenging. Recent studies have demonstrated that the stemness of colon cancer cells is, in part, orchestrated by the microenvironment and is defined by high Wnt activity. In this review article, we will discuss recent progress with respect to intestinal stem cells, cancer stem cells, and the molecular mechanisms of enteric bacteria in the activation of the Wnt pathway. We will also discuss the roles of other pathways, including JAK-STAT, JNK, and Notch, in regulating stem cell niches during bacterial infections using Drosophila models. Insights gained from understanding how host-bacterial interaction during inflammation and cancer may serve as a paradigm for understanding the nature of self-renewal signals.
PKreport: report generation for checking population pharmacokinetic model assumptions
Xiaoyong Sun, Jun Li
BMC Medical Informatics and Decision Making , 2011, DOI: 10.1186/1472-6947-11-31
Abstract: The work described in this paper is about a new R package called PKreport, which is able to generate a collection of plots and statistics for testing model assumptions, visualizing data and diagnosing models. The metric system is utilized as the currency for communicating between data sets and the package to generate special-purpose plots. It provides ways to match output from diverse software such as NONMEM, Monolix, R nlme package, etc. The package is implemented with S4 class hierarchy, and offers an efficient way to access the output from NONMEM 7. The final reports take advantage of the web browser as user interface to manage and visualize plots.PKreport provides 1) a flexible and efficient R class to store and retrieve NONMEM 7 output, 2) automate plots for users to visualize data and models, 3) automatically generated R scripts that are used to create the plots; 4) an archive-oriented management tool for users to store, retrieve and modify figures, 5) high-quality graphs based on the R packages, lattice and ggplot2. The general architecture, running environment and statistical methods can be readily extended with R class hierarchy. PKreport is free to download at http://cran.r-project.org/web/packages/PKreport/index.html webcite.The application of population pharmacokinetic (PopPK) modeling in the drug development has grown in this decade. It has numerous advantages over non-compartmental analysis: incorporating unbalanced designs, modeling sparse data [1-3] and quantifying individual variability. However, these advantages increase the complexity of model bringing additional consideration to the results, and more difficulties in checking how well the model fits the data. This paper describes an R package for generating reports for PopPK models, that contain comprehensive summary statistics and graphics. Graphics play an important and unique role in PopPK model building through exploring hidden structure among data before modeling, evaluating model fit, and va
The Risk Study and Control in Investment Decision
Jun Li,Yanbin Sun
International Journal of Business and Management , 2009, DOI: 10.5539/ijbm.v3n7p140
Abstract: We give the descriptions of the concepts of investment and risk related to investment first. Then, we consider how to measure the rates of return and the risk for alternative investments, and what factors determine an investor’s required rate of return on an investment in the second section. In order to control the risk systematically, the portfolio control process is proposed in section 3. Section 4 describes in detail the three major composite equity portfolio performance measures that combine risk and return performance into a single value. We describe each measure and its intent, and then demonstrate how to compute it and interpret the results. We also compare two of the measures and discuss how they differ and why they rank portfolios differently. The real application on the risk study and control in investment is discussed at the end.
QoS Aware Query Processing Algorithm for Wireless Sensor Networks
Jun-Zhao Sun
Journal of Computers , 2008, DOI: 10.4304/jcp.3.11.32-41
Abstract: In sensor networks, continuous query is commonly used for collecting periodical data from the objects under monitoring. This sort of queries needs to be carefully designed, in order to minimize the power consumption and maximize the lifetime of the sensor nodes. Data reduction techniques can be employed to decrease the size and frequency of data to be transferred in the network, and therefore save energy. This paper presents a novel method for optimizing sliding window based continuous queries. In particular, we deal with two categories of aggregation operations: stepwise aggregation (e.g. MAX, MIN, SUM, COUNT, AVERAGE, etc.) and direct aggregation (e.g. MEDIAN). Our approach is, by using packet merging or compression techniques, to reduce the data size to the best extent, so that the total performance is optimal. A QoS weight item is specified together with a query, in which the importance of the four factors, power, delay, accuracy and error rate can be expressed. Then an optimal query plan can be obtained by studying all the factors simultaneously, leading to the minimum cost. System models for energy and time consumptions of communication are created. Problem is formalized and algorithm is described in detail. Finally, experiments are conducted to validate the effectiveness of the proposed method.
Study on the Transaction Patterns based on the Characteristics of Transactions between Agricultural Enterprises and Farmers
Jun Zhang,Jian Sun
Journal of Modern Agriculture , 2013,
Abstract: In this article, 417 copies of peasant household survey data has been utilized to analyze the impact of transaction characteristics and trading patterns on flexible and sales performance of trading by means of multiple regression model. The results show that there has a positive impact seller's asset specificity makes on performance of both flexibility and sales, compared to the insignificant impact buyer’s asset specificity makes; in addition, transaction uncertainty and trading frequency have a positive impact on flexibility and sales performance, respectively; while market-practice in trading patterns is contributive to both flexible and sales performance, however, the pattern of explicit contract trading only has a contribution to flexible performance, in contrast with vertically integrated trading pattern which has little contribution to flexible and sales performance. In conclusion, it has been pointed out that these measurement should be taken such as the decline of transaction cost in the trade of agricultural resources; the improvement for farmers both in the awareness of systematism as well as in the specificity of their assert; and the encouragement on the application of modern trade devices.
Access to Collective Litigations in China: A Tough Work
Jun Xie,Lijuan Sun
Journal of Politics and Law , 2010, DOI: 10.5539/jpl.v3n1p45
Abstract: Since the legislation of the China’s 1991Civil Procedure Law (CPL), which explicitly permits three types of collective actions, multi-plaintiff groups have brought suits seeking compensation. With the high tempo in economy and the social reform, disputes related to collective parties arise rapidly, class rushes to China’s courtrooms. The increasing number of collective actions is one of the remarkable aspects of the civil litigation explosion in resent years in China. Series of “Judicial Interpretations” issued by the Supreme People’s Court (SPC) which show SPC’s hostile attitude to the collective litigation have triggered the fire among the scholars. To release heavy pressure in the collective litigation, the SPC and the local courts turn to alternative resolutions, such as the mediation and the test case device. Attention should be paid to the SPC’s policies and their impact to the multi-plaintiff disputes so as to get a deep understanding about the collective litigation in China. The purpose of this article is to set forth that claimants’ access to collective litigation a very tough work under the SPC’s policies and other related guidelines.
Multi-Threshold Based Data Gathering Algorithms for Wireless Sensor Networks
Jun-Zhao Sun
Journal of Networks , 2009, DOI: 10.4304/jnw.4.1.30-41
Abstract: Sensor networks have recently attracted significant attention for many military and civil applications, such as environment monitoring, target tracking, and surveillance. A high-level abstraction of sensor networks forms the distributed database view, in which query is adopted to retrieve data from the network. Continuous query is an important approach that is commonly used for collecting real-time data. Sensor nodes have limited energy resources and their functionality continues until their energy drains. Therefore, query for sensor networks, and especially continuous query, should be wisely designed to extend the lifetime of sensors. This paper presents a query optimization method for continuous data gathering in sensor networks. The method is based on the flexible setting of thresholds and the analysis on the content to be sent over the network. Thresholds represent the accuracy requirement of the application issuing the queries. Thus at each single sensor node, instead of direct delivery of each result data, data communication is needed only when the current data is out of the range constrained by the thresholds. A series of static and dynamic algorithms are proposed for the flexible setting of threshold values. In particular, the paper studies deeply the situation where phenomena under monitoring appear a periodical feature. An initiative data model is first created, and then at each single sensor node, instead of direct delivery of each result data, data communication is needed only when the current data is out of the range constrained by the periodical data model. The performance of the proposed algorithms shows that the proposed methods can achieve better performance than without performing the optimization.
Determination of fast electron energy dependence of magic angles in electron energy loss spectroscopy for anisotropic systems
Yuekui Sun,Jun Yuan
Physics , 2004,
Abstract: We present an accurate determination of the magic angle conditions at which the sample-orientation induced fine structure variation is eliminated in the core-level electron energy loss spectroscopy of anisotropic systems. Our result paves the way for the application of magic angle electron energy loss spectroscopy (MAEELS) in material characterization. It also highlights, for the first time, the importance of the quantum interference effect between longitudinal and transverse interactions for medium energy fast electrons, and its connection with the anisotropy of the electron transition.
A remark on a Bernstein type theorem for entire Willmore graphs in R^3
Yong Luo,Jun Sun
Mathematics , 2011,
Abstract: In this note we prove that every two-dimensional entire Willmore graph in $R^3$ with square integrable mean curvature is a plane.
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