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Search Results: 1 - 10 of 32014 matches for " FANG Qiang-En "
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Evolutionary response of staminal lever mechanism of different species in Salvia to spatial variation in pollinators
鼠尾草属不同物种的雄蕊杠杆机制对传粉者空间变异的进化响应

ZHANG Bo,SUN Shan,FANG Qiang-En,BAI Xiao-Ming,
张勃
,孙杉,方强恩,白小明

植物生态学报 , 2012,
Abstract: Aims Floral diversification in animal-pollinated species was widely believed to be driven by pollinator-mediated natural selection in response to the geographical mosaic of pollinators. Our objective was to explore the evolutionary response of staminal lever mechanism in Salvia to variation in pollinator assemblage in a spatial context. Methods We employed three species (four populations) and conducted comparative studies on pollinator-flower interactions in different populations through investigating pollinator assemblage and measuring floral traits and body size of pollinators. Important findings Floral traits investigated, including corolla length, staminal lever length and other structural traits, exhibited distinct differences among populations. These corresponded with variations in composition of pollinators and the main pollinator and its body size in each population. The two types of pollination modes in each population were ventral pollination and dorsal pollination, which was the effective one. The main pollinator’s body length was significantly positively correlated with staminal lever length and negatively correlated with corolla length in spatial context. Both corolla entrance height and stigma height were related to variation in body thickness of the main pollinator among populations. In conclusion, the vulnerability of lever-like stamens and other relevant floral traits to the geographical mosaic of pollinators implies the key role that the staminal lever plays in pollination, and its high evolutionary plasticity might have contributed to adaptive radiation of species in Salvia.
GRB 121027A: long-lasting, energetic X-ray flares and clues to radiation mechanism and progenitor star
Fang-kun Peng,You-Dong Hu,Shao-Qiang Xi,Xiang-Gao Wang,Rui-Jing Lu,En-Wei Liang,Bing Zhang
Physics , 2013,
Abstract: GRB 121027A is un-usual with its extremely long-lasting, energetic X-ray flares. The total energy release in X-ray flares is about one order of magnitude higher than prompt gamma-rays, making it special from most long GRBs. We show that while the prompt gamma-ray emission satisfies the empirical E_{iso}-E_{p} relation of typical long GRBs, the X-ray flares, whose spectra can be fit with a cutoff-power-law model with well-constrained E_p, significantly deviate from such a relation. Nonetheless, a time-resolved spectral analysis of X-ray flares suggest that the X-ray emission is consistent with the L_{iso}-E_{p} relation of long GRBs. We constrain the minimum Lorentz factor of the X-ray flares to be ~14, which is consistent with the Gamma-L_{iso} relation. Our results imply that prompt gamma-ray emission and late X-ray flares share the similar radiation mechanism, but originate from the outflows with different Lorentz factors. We search for similar GRBs from the Swift GRB archives, and find that the z=6.29 GRB 050904 is a carbon copy of GRB 121027A. The long-lasting, energetic X-ray flares in these GRBs demand significant accretion at late times, which point towards a large-radius progenitor star.
Internal Energy Dissipation of Gamma-Ray Bursts Observed with Swift: Precursors, Prompt Gamma-rays, Extended emission and Late X-ray Flares
You-Dong Hu,En-Wei Liang,Shao-Qiang Xi,Fang-Kun Peng,Rui-Jing Lu,Lian-Zhong LV,Bing Zhang
Physics , 2014, DOI: 10.1088/0004-637X/789/2/145
Abstract: We jointly analyze the gamma-ray burst (GRB) data observed with BAT and XRT on board the Swift mission to present a global view on the internal energy dissipation processes in GRBs, including precursors, prompt gamma-ray emission, extended soft gamma-ray emission, and late X-ray flares. The Bayesian block method is utilized to analyze the BAT lightcurves to identify various emission episodes. Our results suggest that these emission components likely share a same physical origin, which is repeated activation of the GRB central engine. What we observe in the gamma-ray band may be the tip-of-iceberg of more extended underlying activities. The precursor emission, which is detected in about 10% of {\em Swift} GRBs, is preferably detected in those GRBs that have a massive star core-collapse origin. The soft extended emission (EE) tail, on the other hand, is preferably detected in those GRBs that have a compact star merger origin. Bright X-ray emission is detected during the BAT quiescent phases prior to subsequent gamma-ray peaks, implying that X-ray emission may be detectable prior the BAT trigger time. Future GRB alert instruments with soft X-ray capability would be essential to reveal the early stage of GRB central engine activities, sheding light into jet composition and jet launching mechanism in GRBs.
Photosphere emission in the X-Ray Flares of Swift Gamma-Ray Bursts and Implications for the Fireball Properties
Fang-Kun Peng,En-Wei Liang,Xiang-Yu Wang,Shu-Jin Hou,Shao-Qiang Xi,Rui-Jing Lu,Jin Zhang,Bing Zhang
Physics , 2014, DOI: 10.1088/0004-637X/795/2/155
Abstract: X-ray flares of gamma-ray bursts (GRBs) are usually observed in the soft X-ray range and the spectral coverage is limited. In this paper, we present an analysis of 32 GRB X-ray flares that are simultaneously observed by both BAT and XRT on board the Swift mission, so a joint spectral analysis with a wider spectral coverage is possible. Our results show that the joint spectra of 19 flares are fitted with the absorbed single power-law or the Band function models. More interestingly, the joint spectra of the other 13 X-ray flares are fitted with the absorbed single power-law model plus a black body (BB) component. Phenomenally, the observed spectra of these 13 flares are analogous to several GRBs with a thermal component, but only with a much lower temperature of $kT=1\sim 3$ keV. Assuming that the thermal emission is the photosphere emission of the GRB fireball, we derive the fireball properties of the 13 flares that have redshift measurements, such as the bulk Lorentz factor $\Gamma_{\rm ph}$ of the outflow. The derived $\Gamma_{\rm ph}$ range from $50$ to $150$ and a relation of $\Gamma_{\rm ph}$ to the thermal emission luminosity is found. It is consistent with the $\Gamma_0-L_{\rm iso}$ relation that are derived for the prompt gamma-ray emission. We discuss the physical implications of these results within the content of jet composition and radiation mechanism of GRBs and X-ray flares.
MiRNA profile in esophageal squamous cell carcinoma: Downregulation of miR-143 and miR-145
Bing-Li Wu, Li-Yan Xu, Ze-Peng Du, Lian-Di Liao, Hai-Feng Zhang, Qiao Huang, Guo-Qiang Fang, En-Min Li
World Journal of Gastroenterology , 2011,
Abstract: AIM: To investigate the expression profile of miRNA in esophageal squamous cell carcinoma (ESCC).METHODS: The expression profile of miRNA in ESCC tissues was analyzed by miRNA microarray. The expression levels of miR-143 and miR-145 in 86 ESCC patients were determined by real-time polymerase chain reaction (PCR) using TaqMan assay. The mobility effect was estimated by wound-healing using esophageal carcinoma cells transfected with miRNA expression plasmids.RESULTS: A set of miRNAs was found to be deregulated in the ESCC tissues, and the expression levels of miR-143 and -145 were significantly decreased in most of the ESCC tissues examined. Both miR-143 and miR-145 expression correlated with tumor invasion depth. The transfection of human esophageal carcinoma cells with miR-143 and miR-145 expression plasmids resulted in a greater inhibition of cell mobility, however, the protein level of the previously reported target of miR-145, FSCN1, did not show any significant downregulation.CONCLUSION: These findings suggest that the deregulation of miRNAs plays an important role in the progression of ESCC. Both miR-143 and miR-145 might act as anti-oncomirs common to ESCC.
A Unified Approach of Observability Analysis for Airborne SLAM
Qiang Fang,Xinsheng Huang
Computer Science , 2012,
Abstract: Observability is a key aspect of the state estimation problem of SLAM, However, the dimension and variables of SLAM system might be changed with new features, to which little attention is paid in the previous work. In this paper, a unified approach of observability analysis for SLAM system is provided, whether the dimension and variables of SLAM system are changed or not, we can use this approach to analyze the local or total observability of the SLAM system.
Iterated Logarithm Laws on GLM Randomly Censored with Random Regressors and Incomplete Information  [PDF]
Qiang Zhu, Zhihong Xiao, Guanglian Qin, Fang Ying
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.23043
Abstract: In this paper, we define the generalized linear models (GLM) based on the observed data with incomplete information and random censorship under the case that the regressors are stochastic. Under the given conditions, we obtain a law of iterated logarithm and a Chung type law of iterated logarithm for the maximum likelihood estimator (MLE) in the present model.
Organochlorines in sediments and mussels collected from coastal sites along the Pearl River Delta,South China
FANG Zhan-qiang,
FANG
,Zhan-qiang

环境科学学报(英文版) , 2004,
Abstract: The level and pattern of residues of organochlorine pesticide and polychlorinated biphenyls (PCBs) wereanalyzed in sediment and mussel( Perna viridis) samples from ten coastal sites along the Pearl River Delta, SouthChina. The range of total HCH was < 0.01 to 0.29 ng/g freeze-dried weight in sediment, and < 0.01 to 1.35 ng/glipid weight in mussels. Average total DDTs concentrations ranged from < 0.01 to 1.04 ng/g in sediment, and< 0.01 to 148.5 ng/g in mussels. Average total PCB concentrations ranged from 16.4 to 198.6 ng/g in sediment,and from 41 to 729.2 ng/g in mussels. Organochlorine pesticide and PCBs in mussels and sediments presentedsimilar distribution patterns. The regression analysis indicated that PCBs concentrations in mussels were significantlycorrelated ( p < 0.01 ) with concentrations in sediments. However, their concentrations in mussels were several timeshigher than the concentration detected in surrounding sediments. The major fraction of DDT related compoundsmeasured in mussels and sediments was DDD. Based on average PCB concentrations, penta-, hexa-, andtetrachlorobiphenyls were preferentially accumulated by mussels as compared to the average sediment composition.According to the present results, three organochlorine polluted "hot spot" sites, including Victoria Harbour, LingdingYang and Huangmao Sea, were found in the Pearl River estuarine zone. HCHs, DDTs and PCBs in all musselsamples were below the limits of 2, 0.2 and 5.0 μg/g wet weight recommended by the Technical Group ofGuangdong Coastal Zone Resource Comprehensive Survey and U. S. Food and Drug Administration.
Transformation, Deformation and Microstructure Characteristics of Ru50Ta50 High Temperature Shape Memory Alloy
Zhirong HE,Fang WANG,Jing''''en ZHOU,
Zhirong
,HE,Fang,WANG,Jing'en,ZHOU

材料科学技术学报 , 2006,
Abstract: The basic martensitic transformation(MT)properties of Ru50Ta50 alloy, i.e. MT temperature(MTT), temperature hysteresis(△T), and MT heat(△H)were investigated in this paper. The effects of heat treatment and thermal cycling on MT behavior of Ru50Ta50 alloy, the deformation and microstructure characteristics of Ru50Ta50 alloy were also studied for its engineering application as high temperature actuator/sensor materials by means of differential scanning calorimetry, X-ray diffraction, transmission electron microscope, optical microscope, and hardness test. The results showed that a two-stage reversible MT takes place in Ru50Ta50 alloy.The two-stage MT starting temperatures(M1s, M2s)and the temperature hysteresis(△T1, △T2)are 1047,784 and 11, 14℃, respectively. No significant effect of aging treatment and thermal cycling on MTT and △T of Ru50Ta50 alloy were observed, but △H decreases slowly with increasing thermal cycles. The hardness and brittleness of Ru50Ta50 alloy are high. The deformation mode of RuTa alloys is twinning.
New endoscopic classification of achalasia for selection of candidates for peroral endoscopic myotomy
Hui-Kai Li,En-Qiang Linghu
World Journal of Gastroenterology , 2013, DOI: 10.3748/wjg.v19.i4.556
Abstract: AIM: To propose a new endoscopic classification of achalasia for selecting patients appropriate for undergoing peroral endoscopic myotomy (POEM). METHODS: We screened out the data of patients with achalasia examined from October 2000 to September 2011 at our Digestive Endoscopic Center with endoscopic pictures clear enough to reveal the morphology of middle and lower esophagus. After analyzing the correlation between the endoscopic morphology of the esophageal lumen and POEM, we proposed a new endoscopic classification (Ling classification) of achalasia according to three kinds of endoscopically viewed structures: multi-ring structure, crescent-like structure and diverticulum structure. There were three types based on the criteria of Ling classification: type I, smooth without multi-ring, crescent-like structure or diverticulum structure; type II, with multi-ring or crescent-like structure but without diverticulum structure; and type III, with diverticulum structure. Type II was classified into three subtypes: Ling IIa, Ling IIb and Ling IIc; and type III also had three subtypes: Ling IIIl, Ling IIIr and Ling IIIlr. Two endoscopists made a final decision upon mutual agreement through discussion if their separately recorded characteristics were different. RESULTS: Among the 976 screened patients with achalasia, 636 patients with qualified endoscopic pictures were selected for the analysis, including 405 males and 231 females. The average age was 42.7 years, ranging from 6 to 93 years. Type I was the most commonly observed type of achalasia, accounting for 64.5% (410/636), and type III was the least commonly observed type of achalasia, accounting for 2.8% (18/636). And type II accounted for 32.7% (208/636) and subtype of Ling IIa, Ling IIb and Ling IIc accounted for 14.6% (93/636), 9.9% (63/636) and 8.2% (52/636), respectively. And subtype of Ling IIIl, Ling IIIr and Ling IIIlr accounted for 0.8% (5/636), 0.3% (2/636) and 1.7% (11/636), respectively. CONCLUSION: A new endoscopic classification of achalasia is proposed that might help in determining the proper candidates for POEM.
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