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Search Results: 1 - 10 of 28418 matches for " Dongquan Sun "
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Sedimentary Characteristics of Stromatolites in Cambrian Strata in Songzi Liujiachang Area and Its Paleoenvironmental Significance  [PDF]
Mei Chen, Chuantao Xiao, Jun Cheng, Xilin Hu, Dongquan Sun
Open Journal of Yangtze Oil and Gas (OJOGas) , 2018, DOI: 10.4236/ojogas.2018.32007
Abstract: Stratiform, irregularly stratiform and columnar stromatolites are found in the third section of Qingjiamiao Group, while columnar and hemispherical stromatolites are found in Sanyoudong Group in Cambrian strata in Songzi Liujiachang area. 1) From the stratiform and columnar stromatolites to hemispherical stromatolites, the internal plaster content is decreasing. And from obvious layer characteristics to intermittent layer characteristics, they reflect that the hydrodynamic conditions are strengthening gradually. 2) From the perspective of sedimentary petrology and the classification of stromatolites, it is concluded that the combinations of stromatolites in different sedimentary environments are different and the main sedimentary facies of different types are different: a) Stratiform (including irregularly statiform) and columnar stromatolites are mainly distributed in the upper tidal zone; columnar and hemispherical stromatolites mainly distribute in the intertidal zone. b) The stratiform stromatolites are mainly found in the upper tidal zone with weak hydrodynamic conditions, while the columnar and hemispherical stromatolites are mainly found in powerful hydrodynamic conditions of the lower intertidal zone. 3) A mass extinction of part of the metazoan is the main reason for the growth of stromatolites in Cambrian strata in Songzi.
Gene expression profiling in soybean under aluminum stress: genes differentially expressed between Al-tolerant and Al-sensitive genotypes  [PDF]
Dechassa Duressa, Khairy M. Soliman, Dongquan Chen, Robert W. Taylor
American Journal of Molecular Biology (AJMB) , 2011, DOI: 10.4236/ajmb.2011.13016
Abstract: It is well documented that aluminum (Al) toxicity is the most important constraint to crop production on acid soils and soybean is one of the most Al sensitive plant species. To advance our understanding of the molecular and genetic mechanisms of Al-tolerance in soybean we compared root tip (1 cm long) transcriptome profiles of an Al-tolerant (PI 416937) and Al-sensitive (Young) soybean genotypes using a combination of DNA microarrays and quantitative real-time PCR gene expression profiling technologies, in a time-course experiment (2, 12, 48, 72 h post Al treatment). We observed many genes differentially expressed between the two genotypes in constitutive and non-constitutive manner. The most likely candidate Al-tolerance genes expressed at high level include the previously reported transcription factors, auxin down regulated-like protein (ADR6-like) and, basic leucine zipper (bZIP 94), sulfur transmembrane transport protein and lipid transfer protein; and several novel genes that include rare cold inducible protein (RCI2B ), GPI-transamidase, malonyl-COA: Isoflavone 7-O-glucoside-6"-O-malontransferase, a cell proliferation protein (WPP2), oleosin protein, pectinestrease inhibitor, and impaired sucrose induction1; whereas genes negatively correlated with Al-tolerance, namely cellulose synthase and calcium transporters were down regulated in Al-tolerant PI 416937 compared to the Al-sensitive Young. The possible mechanisms of how these genes contribute to Al-tolerance trait are discussed. In conclusion, transcriptome profile comparisons of Al-tolerant and Al-sensitive soybean genotypes revealed novel putative Al-tolerance genes. These genes deserve further functional characterization for eventual utilization in developing soybean germplasm adapted to high aluminum soils.
Identification of Aluminum Responsive Genes in Al-Tolerant Soybean Line PI 416937
Dechassa Duressa,Khairy Soliman,Dongquan Chen
International Journal of Plant Genomics , 2010, DOI: 10.1155/2010/164862
Abstract: Soybean is one of the most aluminum (Al) sensitive plants. The complex inheritance of Al tolerance trait has so far undermined breeding efforts to develop Al-tolerant soybeans. Discovering the genetic factors underlying the Al tolerance mechanisms would undoubtedly accelerate the pace of such endeavor. As a first step toward this goal, we analyzed the transcriptome profile in roots of Al-tolerant soybean line PI 416937 comparing Al-treated and untreated control plants using DNA microarrays. Many genes involved in transcription activation, stress response, cell metabolism and signaling were differentially expressed. Patterns of gene expression and mechanisms of Al toxicity and tolerance suggest that Cys2His2 and ADR6 transcription activators, cell wall modifying enzymes, and phytosulfokines growth factor play role in soybean Al tolerance. Our data provide insights into the molecular mechanisms of soybean Al tolerance and will have practical value in genetic improvement of Al tolerance trait. 1. Introduction Aluminum (Al) toxicity is a major constraint of crop production on acid soils. In view of the fact that 40% of world’s arable land is acidic [1, 2], Al toxicity remains a major hurdle for increasing world food, fiber, and fuel production particularly via expansion of cultivation into acid soils. Aluminum inflicts a wide range of cellular injuries in plants that ultimately result in reduced root growth, nutrient and water uptake, and productivity [1, 2]. Plants possess some degree of tolerance to Al toxicity that varies among species and genotypes [1, 3–6]. Al tolerance mechanisms include exclusion and internal detoxification. Al exclusion via rhizosphere Al-organic acid anion complex formation is the most widely documented physiological mechanism of Al tolerance in cultivated and wild plants alike [1, 7]. Root-exuded citrate, malate, and oxalate are the key organic acid anions involved in such mechanism. Genes involved in Al-induced root exudation of malate and citrate have been cloned in wheat [8] and sorghum [5], and their variants are being discovered in several plant species. Internal detoxification mechanisms involve the formation of Al complexes with organic acids, acidic polypeptides, and/or proteins and subsequent sequestration of Al in organelles away from sensitive sites in the cell [9, 10]. The genetic components of the internal detoxification pathways are yet to be elucidated. In soybean, Al tolerance is a complex trait perhaps involving several genes and pathways [11, 12]. Quantitative trait loci (QTL) mapping in a population derived from
TOPOLOGICAL CONDITIONS FOR SOLVABILITY OF PSEUDO-TEARING SUBNETWORK
拟裂子网络可解性的拓扑条件

Huang Dongquan,
黄东泉

电子与信息学报 , 1989,
Abstract: The problem for the solvability of pseudo-tearing subnetwark is one of essential investigations of network theory. The results presented would be not only a mathematical conditions, but also a topological conditions for subnetwork solvability. It should guide intuitively to the design of accessible nodes.
Impacts of Urban Transportation Mode Split on CO2 Emissions in Jinan, China
Dongquan He,Fei Meng,Michael Q. Wang,Kebin He
Energies , 2011, DOI: 10.3390/en4040685
Abstract: As the world’s largest developing country, China currently is undergoing rapid urbanization and motorization, which will result in far-reaching impacts on energy and the environment. According to estimates, energy use and carbon emissions in the transportation sector will comprise roughly 30% of total emissions by 2030. Since the late 1990s, transportation-related issues such as energy, consumption, and carbon emissions have become a policy focus in China. To date, most research and policies have centered on vehicle technologies that promote vehicle efficiency and reduced emissions. Limited research exists on the control of greenhouse gases through mode shifts in urban transportation—in particular, through the promotion of public transit. The purpose of this study is to establish a methodology to analyze carbon emissions from the urban transportation sector at the Chinese city level. By using Jinan, the capital of China’s Shandong Province, as an example, we have developed an analytical model to simulate energy consumption and carbon emissions based on the number of trips, the transportation mode split, and the trip distance. This model has enabled us to assess the impacts of the transportation mode split on energy consumption and carbon emissions. Furthermore, this paper reviews a set of methods for data collection, estimation, and processing for situations where statistical data are scarce in China. This paper also describes the simulation of three transportation system development scenarios. The results of this study illustrate that if no policy intervention is implemented for the transportation mode split (the business-as-usual (BAU) case), then emissions from Chinese urban transportation systems will quadruple by 2030. However, a dense, mixed land-use pattern, as well as transportation policies that encourage public transportation, would result in the elimination of 1.93 million tons of carbon emissions—approximately 50% of the BAU scenario emissions.
Molecular profiling of the developing mouse axial skeleton: a role for Tgfbr2 in the development of the intervertebral disc
Philip Sohn, Megan Cox, Dongquan Chen, Rosa Serra
BMC Developmental Biology , 2010, DOI: 10.1186/1471-213x-10-29
Abstract: Lists of IVD and vertebrae enriched genes were generated. Expression patterns for several genes were verified either through in situ hybridization or literature/database searches resulting in a list of genes that can be used as markers of IVD. Cluster analysis using genes listed under the Gene Ontology terms multicellular organism development and pattern specification indicated that mutant IVD more closely resembled vertebrae than wild type IVD. We also generated lists of genes regulated by TGF-β or BMP4 in cultured sclerotome. As expected, treatment with BMP4 resulted in up-regulation of cartilage marker genes including Acan, Sox 5, Sox6, and Sox9. In contrast, treatment with TGF-β1 did not regulate expression of cartilage markers but instead resulted in up-regulation of many IVD markers including Fmod and Adamtsl2.We propose TGF-β has two functions in IVD development: 1) to prevent chondrocyte differentiation in the presumptive IVD and 2) to promote differentiation of annulus fibrosus from sclerotome. We have identified genes that are enriched in the IVD and regulated by TGF-β that warrant further investigation as regulators of IVD development.The vertebral column develops from somites (Reviewed in [1-3]. In response to signals from the notochord and floor plate of the neural tube, the maturing somites will undergo a dorsal-ventral compartmentalization establishing the dermamyotome and sclerotome, the latter forming the future axial skeleton. The ventral part of the sclerotome gives rise to the vertebral bodies and IVD [4]. Due to resegmentation of sclerotome during the formation of the vertebrae, each vertebrae will eventually form from the caudal portion of one somite and the rostral portion of the adjacent somite [5]. The IVD will form at the border of the rostral and caudal domains [6]. IVD are derived from both sclerotome and notochord [7-9]. The outer layer of the IVD, the annulus fibrosus (AF) is derived from sclerotome and provides the structural propertie
GenDrux: A biomedical literature search system to identify gene expression-based drug sensitivity in breast cancer
Chiquito Crasto, Dajie Luo, Feliciano Yu, Andres Forero, Dongquan Chen
BMC Medical Informatics and Decision Making , 2011, DOI: 10.1186/1472-6947-11-28
Abstract: GenDrux, a pilot system, is developed in the domain of breast cancer and can be accessed at http://www.microarray.uab.edu/drug_gene.pl webcite. GenDrux can be queried based on drug, gene and/or disease name. From over 8,000 relevant abstracts from the biomedical literature related to breast cancer, we have archived a corpus of more than 4,000 articles that depict gene expression-drug activity relationships for breast cancer and related cancers. The archiving process has been automated.The successful development, implementation, and evaluation of this and similar systems when created may provide clinicians with a tool for literature management, clinical decision making, thus setting the platform for personalized therapy in the future.Typically, diagnoses for most diseases often result from recognizing disease phenotypes, though these phenotypes might arise from a range of gene expression profiles [1]. Treatment modalities for cancer such as chemotherapy can be personalized to the gene expression profile of a patient, if sensitivity of a pharmaceutical product can be associated specific genes, treating the underlying cause that stems from a patient's specific genotype. This is one of the means by which the eventual goals of personalized medicine, recognition of disease-gene relationships, gene-drug relationships [2], and the disease-gene-drug nexus [3], may be achieved. Table 1 represents salient examples of an increasing number of studies that have shown that recognizing gene-drug and disease-gene relationships can be potentially useful to clinicians. A search in PubMed using the phrase "breast cancer and drug" results in nearly 57,000 abstracts returned, of which nearly 10% are between 2009 and 2010. This is indicative of a greater emphasis on increasing recent work on gene expression contributions to disease within the research and clinical communities. References to new discoveries of these relationships are often available only in the non-annotated, free text of
Personalized online information search and visualization
Dongquan Chen, Helmuth F Orthner, Susan M Sell
BMC Medical Informatics and Decision Making , 2005, DOI: 10.1186/1472-6947-5-6
Abstract: We developed such a database that stored searching terms, journals and et al., and implement a piece of software for searching the medical subject heading-indexed sources such as the Medline and other online sources automatically. The returned information were stored locally, as is, on a server and visible through a Web-based interface. The search was performed daily or otherwise scheduled and the users logon to the website anytime without typing any words. The system has potentials to retrieve similarly from non-medical subject heading-indexed literature or a privileged information source such as a clinical information system. The issues such as security, presentation and visualization of the retrieved information were thus addressed. One of the presentation issues such as wireless access was also experimented. A user survey showed that the personalized online searches saved time and increased and relevancy. Handheld devices could also be used to access the stored information but less satisfactory.The Web-searching software or similar system has potential to be an efficient tool for both bench scientists and clinicians for their daily information needs.The rapid growth of publications available in the Medline and other sources raises the question how to search efficiently while maintaining acceptable relevancy. Without the assistance from domain experts such as medical professionals or librarians, retrieving relevant information from the Internet remains a difficult task. For bench scientists, it is important to monitor articles in their fields constantly on a weekly if not daily basis. For a clinician, it is important to access the patient records anywhere and anytime.These searching procedures often involve relatively simple and similar procedures. For example, they go to certain websites such as the Medline, type in certain words or terms, and then search accordingly using the search engine of that site. Different words or combination reflect different research
INTERVAL ANALYSIS OF ADEQUATE SELEC-TION OF ACCESSIBLE NODES IN A TOLERANCE NETWORK
容差网络可及点合理选择的区间分析法

Cai Jinding,Huang Dongquan,
蔡金锭
,黄东泉

电子与信息学报 , 1995,
Abstract: 本文应用一个新兴的数学分支——区间分析,作为容差网络故障诊断的工具,对子网络级故障诊断中面临的可及点选择问题进行研究。这是工程实际中遇到的一个关键问题。
Vapor Phase Sensing Using Metal Nanorod Thin Films Grown by Cryogenic Oblique Angle Deposition
Piyush Shah,Dongquan Ju,Xiaoxu Niu,Andrew M. Sarangan
Journal of Sensors , 2013, DOI: 10.1155/2013/823041
Abstract: We demonstrate the chemical sensing capability of silver nanostructured films grown by cryogenic oblique angle deposition (OAD). For comparison, the films are grown side by side at cryogenic (~100 K) and at room temperature (~300 K) by e-beam evaporation. Based on the observed structural differences, it was hypothesized that the cryogenic OAD silver films should show an increased surface enhanced Raman scattering (SERS) sensitivity. COMSOL simulation results are presented to validate this hypothesis. Experimental SERS results of 4-aminobenzenethiol (4-ABT) Raman test probe molecules in vapor phase show good agreement with the simulation and indicate promising SERS applications for these nanostructured thin films. 1. Introduction The detection and identification of hazardous chemical and biological agents is important for several areas of defense and security as well as in other industries that deal with hazardous chemicals [1]. Gas chromatography has the advantage of providing quick and accurate detection capability; however cost, size, and lack of portability have limited its widespread use [2]. Ion-mobility spectrometer is another popular technique for chemical sensing; however the level of information that can be extracted is not comparable to most vibrational spectroscopy techniques [3]. Surface enhanced Raman scattering (SERS) has shown the ability to detect the presence of very low concentrations of chemical agents quickly [1, 4–6]. Several groups have also demonstrated a portable Raman setup for chemical and biosensing applications [7, 8]. In many of these applications, colloidal silver nanoparticles are used as the SERS substrates, which limits these to only liquid phase applications [9]. On the other hand, silver nanostructured SERS substrates have the flexibility to work with liquids or vapors. Some of the earlier literature on SERS-based vapor sensing includes simulants for highly toxic chemicals such as nerve and mustard agents [7]. Most of these used electrochemically roughened silver substrates or silver film over nanosphere substrates. All of these techniques are limited by the available surface area for the vapor molecules to bind and adsorb onto. On the other hand, nanorod-based substrates can offer a significantly greater surface area for the same foot print area. Oblique angle physical vapor deposition technique has led to the evolution of a new class of thin films with very large effective surface areas. The technique is based on atomistic level self-shadowing. Whereas in typical thin film deposition setups the substrate is held
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