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Search Results: 1 - 10 of 27607 matches for " Hu Junfei "
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A Sensitivity-based Approach for Identification of Flexible Design Opportunities in Engineering System Design
Junfei Hu,Kim-Leng Poh
Lecture Notes in Engineering and Computer Science , 2011,
Designing Flexible Engineering System Using a Sensitivity-based Method
Junfei Hu,Kim-Leng Poh
Engineering Letters , 2012,
Humanization and Characterization of an Anti-Ricin Neutralization Monoclonal Antibody
Wei-Gang Hu, Junfei Yin, Damon Chau, Laurel M. Negrych, John W. Cherwonogrodzky
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045595
Abstract: Ricin is regarded as a high terrorist risk for the public due to its high toxicity and ease of production. Currently, there is no therapeutic or vaccine available against ricin. D9, a murine monoclonal antibody developed previously in our laboratory, can strongly neutralize ricin and is therefore a good candidate for humanization. Humanization of D9 variable regions was achieved by a complementarity-determining region grafting approach. The humanized D9 (hD9) variable regions were further grafted onto human heavy and light chain constant regions to assemble the complete antibody gene. A foot-and-mouth-disease virus-derived 2A self-processing sequence was introduced between heavy and light chain DNA sequences to cleave the recombinant protein into a functional full-length antibody molecule from a single open reading frame driven by a single promoter in an adenoviral vector. After expression in mammalian cells and purification, the hD9 was demonstrated to have equimolar expression of the full-length antibody heavy and light chains. More importantly, the hD9 exhibited high affinity to ricin with KD of 1.63 nM, comparable to its parental murine D9 (2.55 nM). In a mouse model, intraperitoneal (i.p.) administration of hD9, at a low dose of 5 μg per mouse, 4 hours after the i.p. challenge with 5×LD50 ricin was found to rescue 100% of the mice. In addition, administered 6 hours post-challenge, hD9 could still rescue 50% of the mice. The hD9 has the potential to be used for prophylactic or therapeutic purposes against ricin poisoning.
PFP-RFSM: Protein fold prediction by using random forests and sequence motifs  [PDF]
Junfei Li, Jigang Wu, Ke Chen
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.612145

Protein tertiary structure is indispensible in revealing the biological functions of proteins. De novo perdition of protein tertiary structure is dependent on protein fold recognition. This study proposes a novel method for prediction of protein fold types which takes primary sequence as input. The proposed method, PFP-RFSM, employs a random forest classifier and a comprehensive feature representation, including both sequence and predicted structure descriptors. Particularly, we propose a method for generation of features based on sequence motifs and those features are firstly employed in protein fold prediction. PFP-RFSM and ten representative protein fold predictors are validated in a benchmark dataset consisting of 27 fold types. Experiments demonstrate that PFP-RFSM outperforms all existing protein fold predictors and improves the success rates by 2%-14%. The results suggest sequence motifs are effective in classification and analysis of protein sequences.


Liquid-state fermentation with Bacillus subtilis Bs-07 to enhanceanticoagulant function of Auricularia auricula polysaccharide
Zhang Zhi, Liu Dongmin, Xu Bingxin, Hu Junfei, Liu QiGuo Yong, Liang Zhuoran, Lu Xiangni, Zhao Zichen, Wang Zhenyu
- , 2015, DOI: 10.3969/j.issn.1003-7985.2015.01.024
Abstract: In order to improve the anticoagulant function of Auricularia auricula, Auricularia auricula polysaccharide(AAP)was converted into its derivatives by the microbial fermentation method and then polysaccharide derivatives with stronger anticoagulant activity were prepared. The optimal conditions for fermenting the polysaccharide from A. auricula were examined and the in vitro anticoagulant activities of transformed and untransformed polysaccharides were compared. Response surface tests and an orthogonal experiment indicated that the best conditions for microbial conversion of AAP3 were an AAP3 concentration of 4.0 mg/mL, a ratio of substrate(AAP3)to donor(p-hydroxybenzoic acid)of 40∶1, and a pH of 6.0. Bacillus subtilis Bs-07 was inoculated and then placed on a rotary shaker(120 r/min), followed by fermentation for 48 h at 35 ℃.The conversion rate was found to be greater than 40%. The result of in vitro anticoagulant activity showed that the transformed polysaccharide improved activated partial thromboplastin time, prothrombin time, and thrombin time values and greatly enhanced anticoagulant activity compared to the untransformed polysaccharide.
SPI-based Regional Drought Prediction Using Weighted Markov Chain Model
Junfei Chen,Yang Yang
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: Drought is one of the most serious natural disasters in China. Drought disasters occur frequently and caused huge economic loss in recently. In this paper, a drought prediction model based on weighted Markov Chain is put forward. An application is demonstrated by Anhui province of Huaihe River in China. Based on the precipitation data during 1958-2006 at monthly scale, the different time scales Standardized Precipitation Index (SPI) is computed and the occurrence frequency of extreme drought, severe drought, moderate drought, slight drought and non-drought is obtained. The prediction of SPI is conducted by weighted Markov Chain model and the prediction accuracy is computed for the SPI of different time scales. The results show that weighted Markov Chain model is an effective tool for drought prediction and can provide decision-making for regional drought management.
A QoS Guarantee Strategy for Multimedia Conferencing based on Bayesian Networks
Junfei Huang,Guochu Shou
Computer Science , 2015,
Abstract: Service Oriented Architecture (SOA) is commonly employed in the design and implementation of web service systems. The key technology to enable media communications in the context of SOA is the Service Oriented Communication. To exploit the advantage of SOA, we design and implement a web-based multimedia conferencing system that provides users with a hybrid orchestration of web and communication services. As the current SOA lacks effective QoS guarantee solutions for multimedia services, the user satisfaction is greatly challenged with QoS violations, e.g., low video PSNR (Peak Signal-to-Noise Ratio) and long playback delay. Motivated by addressing the critical problem, we firstly employ the Business Process Execution Language (BPEL) service engine for the hybrid services orchestration and execution. Secondly, we propose a novel context-aware approach to quantify and leverage the causal relationships between QoS metrics and available contexts based on Bayesian networks (CABIN). This approach includes three phases: (1) information discretization, (2) causal relationship profiling, and (3) optimal context tuning. We implement CABIN in a real-life multimedia conferencing system and compare its performance with existing delay and throughput oriented schemes. Experimental results show that CABIN outperforms the competing approaches in improving the video quality in terms of PSNR. It also provides a one-stop shop controls both the web and communication services.
Improving the Luminescence Efficiency of Power White LEDs with Slurry

Li Junfei,Rao Haibo,Hou Bin,Hu Yue,Shen Fahua,

半导体学报 , 2008,
Abstract: The slurry method based on water soluble PVA is discussed.A controlled phosphor layer is obtained by the slurry method on the surface of blue LED chips.Due to the absorption of Cr3+,the luminous intensity of white LEDs can be improved by decreasing the concentration of ADC or increasing the concentration of phosphor in the slurry.The stand-time of slurry for 3~5h was optimized in a darkroom.The hue of output light moved to the blue-light zone and the luminous flux increased from 44.8~59 lm to 79.4~84.9 lm after the silica gel was coated on the LED coated phosphor particles.
Slow Drag in 2D Granular Media
Junfei Geng,R. P. Behringer
Physics , 2004,
Abstract: We study the drag force experienced by an object slowly moving at constant velocity through a 2D granular material consisting of bidisperse disks. The drag force is dominated by force chain structures in the bulk of the system, thus showing strong fluctuations. We consider the effect of three important control parameters for the system: the packing fraction, the drag velocity and the size of the tracer particle. We find that the mean drag force increases as a power-law (exponent of 1.5) in the reduced packing fraction, $(\gamma - \gamma_c)/\gamma_c$, as $\gamma$ passes through a critical packing fraction, $\gamma_c$. By comparison, the mean drag grows slowly (basically logarithmic) with the drag velocity, showing a weak rate-dependence. However, the system nevertheless exhibits strong statistical invariance in the sense that many physical quantities collapse onto a single curve under appropriate scaling. We also show that the system can be understood using simple failure models, which reproduce many experimental observations. These experimental data and simulations indicate that fluctuations in the drag force seem to be associated with the force chain formation and breaking in the system. Moreover, our simulations suggest that the logarithmic increase of the mean drag force with rate can be accounted for if slow relaxation of the force chain networks is included.
Statistical Uncertainty Estimation Using Random Forests and Its Application to Drought Forecast
Junfei Chen,Ming Li,Weiguang Wang
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/915053
Abstract: Drought is part of natural climate variability and ranks the first natural disaster in the world. Drought forecasting plays an important role in mitigating impacts on agriculture and water resources. In this study, a drought forecast model based on the random forest method is proposed to predict the time series of monthly standardized precipitation index (SPI). We demonstrate model application by four stations in the Haihe river basin, China. The random-forest- (RF-) based forecast model has consistently shown better predictive skills than the ARIMA model for both long and short drought forecasting. The confidence intervals derived from the proposed model generally have good coverage, but still tend to be conservative to predict some extreme drought events.
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