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Search Results: 1 - 10 of 23018 matches for " Youjia Liang "
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An Integrated Modelling Approach Inmountainous Watershed of Heihe River Basin, Northwest China  [PDF]
Youjia Liang, Lijun Liu, Zhongmin Xu
Natural Resources (NR) , 2014, DOI: 10.4236/nr.2014.53010
Abstract:

An integrated modelling approach is developed to simulate ecological economics processes of mountainous watershed of Heihe river basin, northwest China. The objectives are 1) a hydrologic unit model HLM_HMU was developed; 2) the impacts of LUCC on the hydrological processes based on different scenarios were simulated respectively; and 3) the Payment for Ecosystem Services (PES) curve of prohibition grazing is given. The hydrological results show that the observed and simulated data have a good fit, in which the Nash–Sutcliffe efficiency, balance error, and explained variance are 0.69, -0.13, and 0.62, respectively; the model can simulate the majority of peaks well; the source code of Spatial Modelling Environment (SME) needs to be deeply understood to improve the algorithms of interpolation and conflux; the PES result shows that prohibition grazing will occur completely when the price of PES reached to 17.42 yuan, and the increased amount of ecosystem services is 2.13 × 108 m3.The main purpose of this paper is to build a better understanding of developing a meaningful integrated model in the study area to solve its ecological and economic problems.

An integrated analysis approach to LUCC at regional scale: A case study in the Ganzhou District of Zhangye City, China

YouJia Liang,ZhongMin Xu,

寒旱区科学 , 2012,
Abstract:
Rapid Determination of Low Molecular Weight Aldehydes in Air by Gas Chromatography
气相色谱法快速测定空气中低分子量醛

Ren Qing,Guo Youjia,
任清
,郭友嘉

色谱 , 1997,
Abstract: This paper reports a method for determination of low molecular weight aldehydes in polluted air by GC-FID using a GDX-401 packed column (3 mm x 3 m). The advantages of this method are simple, rapid, accurate and sensitive. The method requires only 8 minutes for the whole analysis. In the concentration range of 1.7-442.4 mg/m3 for formaldehyde and 0.5-680 mg/m3 for acetaldehyde and propionaldehyde the calibration curves are linear. The minimun detectable amounts are 3.5 ng, 1 ng and 1 ng, and the average recoveries (n=5) are 89.4%, 89.6%, 88.1% for formaldehyde, acetaldehyde and propionaldehyde respectively. The quantitative determination is performed by external standard calibration method. The results of sample analysis are satisfactory.
Robust Facial Features Localization on Rotation Arbitrary Multi-View face in Complex Background
Youjia Fu,He Yan,Jianwei Li,Ruxi Xiang
Journal of Computers , 2011, DOI: 10.4304/jcp.6.2.337-342
Abstract: Focused on facial features localization on multi-view face arbitrarily rotated in plane, a novel detection algorithm based improved SVM is proposed. First, the face is located by the rotation invariant multi-view (RIMV) face detector and its pose in plane is corrected by rotation. After the searching ranges of the facial features are determined, the crossing detection method which uses the brow-eye and nose-mouth features and the improved SVM detectors trained by large scale multi-view facial features examples is adopted to find the candidate eye, nose and mouth regions,. Based on the fact that the window region with higher value in the SVM discriminant function is relatively closer to the object, and the same object tends to be repeatedly detected by near windows, the candidate eyes, nose and mouth regions are filtered and merged to refine their location on the multi-view face. Experiments show that the algorithm has very good accuracy and robustness to the facial features localization with expression and arbitrary face pose in complex background.
Aristolochic Acid I Induced Autophagy Extenuates Cell Apoptosis via ERK 1/2 Pathway in Renal Tubular Epithelial Cells
Youjia Zeng, Xiao Yang, Juan Wang, Jinjin Fan, Qingyu Kong, Xueqing Yu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0030312
Abstract: Autophagy is a lysosomal degradation pathway that is essential for cell survival and tissue homeostasis. However, limited information is available about autophagy in aristolochic acid (AA) nephropathy. In this study, we investigated the role of autophagy and related signaling pathway during progression of AAI-induced injury to renal tubular epithelial cells (NRK52E cells). The results showed that autophagy in NRK52E cells was detected as early as 3–6 hrs after low dose of AAI (10 μM) exposure as indicated by an up-regulated expression of LC3-II and Beclin 1 proteins. The appearance of AAI-induced punctated staining of autophagosome-associated LC3-II upon GFP-LC3 transfection in NRK52E cells provided further evidence for autophagy. However, cell apoptosis was not detected until 12 hrs after AAI treatment. Blockade of autophagy with Wortmannin or 3-Methyladenine (two inhibitors of phosphoinositede 3-kinases) or small-interfering RNA knockdown of Beclin 1 or Atg7 sensitized the tubular cells to apoptosis. Treatment of NRK52E cells with AAI caused a time-dependent increase in extracellular signal-regulated kinase 1 and 2 (ERK1/2) activity, but not c-Jun N-terminal kinase (JNK) and p38. Pharmacological inhibition of ERK1/2 phosphorylation with U0126 resulted in a decreased AAI-induced autophagy that was accompanied by an increased apoptosis. Taken together, our study demonstrated for the first time that autophagy occurred earlier than apoptosis during AAI-induced tubular epithelial cell injury. Autophagy induced by AAI via ERK1/2 pathway might attenuate apoptosis, which may provide a protective mechanism for cell survival under AAI-induced pathological condition.
Identification of critical residues of influenza neuraminidase in viral particle release
Jennifer R Tisoncik, Ying Guo, Katie S Cordero, Jia Yu, Jianwei Wang, Youjia Cao, Lijun Rong
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-14
Abstract: In this report, we established a pseudoviral particle release assay to study NA function, which is based on lentiviral particles pseudotyped with influenza glycoproteins HA and NA as a surrogate system. Through an extensive molecular analysis, we sought to characterize important residues governing NA function. We identified five residues of NA, 234, 241, 257, 286 and 345, four of which (except 345) map away from the active site of NA when projected onto the three-dimensional structure of avian influenza H5N1 NA, and substitutions of these residues adversely affected the NA-mediated viral particle release, suggesting that these residues are critical for NA enzymatic activity.Through extensive chimeric and mutational analyses, we have identified several residues, which map away from the active site and are critical for NA function. These findings provide new insights into NA-mediated pseudoviral particle release and may have important implications in drug design and therapeutics against influenza infection.Influenza virus causes acute respiratory infections resulting in an estimated 300,000 deaths worldwide each year, of which approximately 36,000 deaths occur in the United States alone. Equally concerning is the emergence of new viral strains in the human population, including the ongoing H5N1 epizootic and swine-origin H1N1 pandemic[1-8]. While influenza vaccines are available, they must be reformulated annually to control for antigenic drift and shift of the two major envelope glycoproteins, hemagglutinin (HA) and neuraminidase (NA). HA binds N-acetyl neuraminic acid (Neu5Ac) mediating virus entry, whereas NA catalyzes Neu5Ac receptor removal facilitating viral particle release. The abundance of Neu5Ac on the cellular surface can impede influenza egress making NA critical for sustained virus infection. NA is one example where an enveloped virus has evolved a mechanism to promote influenza virus release, making optimal influenza virus spread and infection [9,10].Sev
Photostimulation activates restorable fragmentation of single mitochondrion by initiating oxide flashes
Yintao Wang,Hao He,Shaoyang Wang,Yaohui Liu,Minglie Hu,Youjia Cao,Chingyue Wang
Quantitative Biology , 2015,
Abstract: Mitochondrial research is important to ageing, apoptosis, and mitochondrial diseases. In previous works, mitochondria are usually stimulated indirectly by proapoptotic drugs to study mitochondrial development, which is in lack of controllability, or spatial and temporal resolution. These chemicals or even gene techniques regulating mitochondrial dynamics may also activate other inter- or intra-cellular processes simultaneously. Here we demonstrate a photostimulation method on single-mitochondrion level by tightly-focused femtosecond laser that can precisely activate restorable fragmentation of mitochondria which soon recover their original tubular structure after tens of seconds. In this process, series of mitochondrial reactive oxygen species (mROS) flashes are observed and found very critical to mitochondrial fragmentation. Meanwhile, transient openings of mitochondrial permeability transition pores (mPTP), suggested by oscillations of mitochondrial membrane potential, contribute to the scavenging of redundant mROS and recovery of fragmented mitochondria. Those results demonstrate photostimulation as an active, precise and controllable method for the study of mitochondrial oxidative and morphological dynamics or related fields.
miRConnect: Identifying Effector Genes of miRNAs and miRNA Families in Cancer Cells
Youjia Hua, Shiwei Duan, Andrea E. Murmann, Niels Larsen, J?rgen Kjems, Anders H. Lund, Marcus E. Peter
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026521
Abstract: micro(mi)RNAs are small non-coding RNAs that negatively regulate expression of most mRNAs. They are powerful regulators of various differentiation stages, and the expression of genes that either negatively or positively correlate with expressed miRNAs is expected to hold information on the biological state of the cell and, hence, of the function of the expressed miRNAs. We have compared the large amount of available gene array data on the steady state system of the NCI60 cell lines to two different data sets containing information on the expression of 583 individual miRNAs. In addition, we have generated custom data sets containing expression information of 54 miRNA families sharing the same seed match. We have developed a novel strategy for correlating miRNAs with individual genes based on a summed Pearson Correlation Coefficient (sPCC) that mimics an in silico titration experiment. By focusing on the genes that correlate with the expression of miRNAs without necessarily being direct targets of miRNAs, we have clustered miRNAs into different functional groups. This has resulted in the identification of three novel miRNAs that are linked to the epithelial-to-mesenchymal transition (EMT) in addition to the known EMT regulators of the miR-200 miRNA family. In addition, an analysis of gene signatures associated with EMT, c-MYC activity, and ribosomal protein gene expression allowed us to assign different activities to each of the functional clusters of miRNAs. All correlation data are available via a web interface that allows investigators to identify genes whose expression correlates with the expression of single miRNAs or entire miRNA families. miRConnect.org will aid in identifying pathways regulated by miRNAs without requiring specific knowledge of miRNA targets.
Role of IRAK-M in Alcohol Induced Liver Injury
Yipeng Wang, Youjia Hu, Chen Chao, Muhammed Yuksel, Isabelle Colle, Richard A. Flavell, Yun Ma, Huiping Yan, Li Wen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0057085
Abstract: Increasing evidence suggests that innate immunity plays an important role in alcohol-induced liver injury and most studies have focused on positive regulation of innate immunity. The main objective of this study was to investigate the negative regulator of innate immunity, IL-1/Toll-like receptor (TLR) signaling pathways and interleukin receptor-associated kinase-M (IRAK-M) in alcoholic liver injury. We established an alcohol-induced liver injury model using wild type and IRAK-M deficient B6 mice and investigated the possible mechanisms. We found that in the absence of IRAK-M, liver damage by alcohol was worse with higher alanine transaminase (ALT), more immune cell infiltration and increased numbers of IFNγ producing cells. We also found enhanced phagocytic activity in CD68+ cells. Moreover, our results revealed altered gut bacteria after alcohol consumption and this was more striking in the absence of IRAK-M. Our study provides evidence that IRAK-M plays an important role in alcohol-induced liver injury and IRAK-M negatively regulates the innate and possibly the adaptive immune response in the liver reacting to acute insult by alcohol. In the absence of IRAK-M, the hosts developed worse liver injury, enhanced gut permeability and altered gut microbiota.
The Role of Space Dimension on the Blow up for a Reaction-Diffusion Equation  [PDF]
Zhilei Liang
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.25076
Abstract: This paper deals with the doubly degenerate reaction-di?usion equation where , , and B(0,1) denotes a unit ball in RN with the center in origin. We prove that the blow up phenomenon can be restrained if the space dimension N is taken su?ciently large. Moreover, the critical condition guaranteeing the absence (or occurrence) of the blow up is achieved.
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