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Now showing items 49 - 64 of 121

  • Lossless and Content-based Hidden Transmission for Biometric Verificaion

    Lu, Yinghua   Li, Xiaolu   Qi, Miao   Li, Jinsong   Fu, Yao   Kong, Jun  

    This paper presents a novel lossless and content-based hidden transmission method of biometric images to improve the security and secrecy of biometric verification. Chaos is used to encrypt the watermark. The secret keys which called biokey are generated from the biometric image and used as the parameter value and initial condition of the chaotic map. The digital watermark embedded losslessly in the region of interest (ROI) of palmprint is used to recognize the paImprint has been destroyed or not and regarded as a user information index for verification. The watermarked ROI is hidden in the general public image using content-based steganography technology and transmitted secretly in case of attracting the attackers' attention. Our method can overcome the disadvantage of block-based steganographic techniques. Experimental results show that the security and performance of the proposed scheme are high.
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  • Day-Ahead Wind Speed Forecasting Using Relevance Vector Machine

    Sun, Guoqiang   Chen, Yue   Wei, Zhinong   Li, Xiaolu   Cheung, Kwok W.  

    With the development of wind power technology, the security of the power system, power quality, and stable operation will meet new challenges. So, in this paper, we propose a recently developed machine learning technique, relevance vector machine (RVM), for day-ahead wind speed forecasting. We combine Gaussian kernel function and polynomial kernel function to get mixed kernel for RVM. Then, RVM is compared with back propagation neural network (BP) and support vector machine (SVM) for wind speed forecasting in four seasons in precision and velocity; the forecast results demonstrate that the proposed method is reasonable and effective.
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  • Structure mediation and ductility enhancement of poly(L-lactide) by random copolymer poly(D-lactide-co-epsilon-caprolactone)

    Zhang, Xiuqin   Yin, Yongai   Song, Yan   Li, Xiaolu   Dong, Zhenfeng   Wang, Rui   Wang, De-Yi  

    Two types of random copolymer poly(D-lactide-co-epsilon-caprolactone) (PDLA-r-PCL) were added into poly(L-lactide) (PLLA) matrix by melt blending. The structure and property of PLLA/PDLA-r-PCL blends were investigated by thermal gravimetric analysis, differential scanning calorimetry, scanning electron microscopy, wide-angle X-ray diffraction, and mechanical measurement. The results suggested that PDLA-r-PCL had little effect on the thermal property of PLLA. PDLA-r-PCL uniformly dispersed in PLLA matrix, which contributed to the improvement of stretching properties. During stretching at 25 degrees C, with the increased content of PDLA-r-PCL, the elongation at break of PLLA increased and the strength decreased. The degree of decrease in fracture strength was related to the molecular structure of PDLA-r-PCL. When a small amount of stereocomplex crystals (SC) were formed in PLLA/PDLAr-PCL blends, the strength was maintained or slightly enhanced even though the elongation at break of the blends was significantly improved by soft chains of PCL. It might be caused by the synergistic effects of SC crystals and plasticization of PCL chains.
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  • Hydrogen peroxide-inactivated bacteria induces potent humoral and cellular immune responses and releases nucleic acids

    Fan, Yingzi   Mu, Yandong   Lu, Lian   Tian, Yaomei   Yuan, Fengjiao   Zhou, Bailing   Yu, Chaoheng   Wang, Zhenling   Li, Xiaolu   Lei, Song   Xu, Ying   Wu, Dongming   Yang, Li  

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  • Rational design of a novel turn-on fluorescent probe for the detection and bioimaging of hydrazine with barbituric acid as a recognition group

    Du, Junli   Li, Xiaolu   Ruan, Songsong   Li, Yingchun   Ren, Fan   Cao, Yanjun   Wang, Xiaoqing   Zhang, Yongmin   Wu, Shaoping   Li, Jianli  

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  • Study on Injection Characteristics of Diesel and DME

    Li, Xiaolu   Chen, Zichen   Xu, Lijun  

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  • Information Literacy Education for Improving Innovative Ability of Postgraduate in China

    Wang, Xu   Li, Xiaolu  

    Cultivating the innovative abilities of postgraduates is the key for promoting the quality education comprehensively; and also is the main content in the postgraduate education in China. By listing and explaining the disadvantages of the innovation capacity of postgraduate in China; this paper points out that the information literacy education is one of the most important measures in advancing their innovative abilities. The postgraduates should possess these information competences during their innovative ability cultivation; such as acquiring the needed information effectively and efficiently; incorporating selected information into knowledge base; using information effectively to accomplish a specific purpose; and having good information ethics. After analyzing the states of the information literacy education of postgraduates in China; such as lack of information literacy courses; outdated teaching methods and content; lack of information education resources in universities; and lack of the competent teachers for the postgraduate information education; some measures are put forward to improve the postgraduate information literacy; such as constructing a digitized learning environment by building the digital campus and digital library; speeding up the reform of the courses; making use of the information sources to improve the information literacy education and media literacy education; teaching on-line; directing the postgraduates in developing the information literacy.
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  • A Novel Hidden Transmission of Biometric Images Based on Chaos and Image Content

    Kong, Jun   Yang, Zhiqiang   Qi, Zhi   Li, Xiaolu  

    This paper presents a novel hidden transmission method of biometric images base on chaos and image content to improve the security and secrecy of biometric verification. In our scheme, chaos is used to encrypt the watermark. The secret keys which called biokey are generated from the biometric image and used as the parameter value and initial condition of the chaotic map. The digital watermark embedded in the region of interest (ROI) of palmprint is used to recognize the palmprint has been destroyed or not and regarded as a user information index for verification. The watermarked ROI is hidden in the general public image using content-based steganography technology and transmitted secretly in case of attracting the attackers’; attention. ; ;Our method can overcome the disadvantage of block-based steganographic techniques. Experimental results show that the security and performance of the proposed scheme are high.
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  • Inhibition of neuroblastoma proliferation by PF-3758309, a small-molecule inhibitor that targets p21-activated kinase 4.

    Li, Zhiheng   Li, Xiaolu   Xu, Lixiao   Tao, Yanfang   Yang, Chun   Chen, Xiaolan   Fang, Fang   Wu, Yi   Ding, Xin   Zhao, He   Li, Mei   Qian, Guanghui   Xu, Yunyun   Ren, Junli   Du, Weiwei   Wang, Jian   Lu, Jun   Hu, Shaoyan   Pan, Jian  

    Neuroblastoma is the most common extracranial solid childhood tumor. Despite the availability of advanced multimodal therapy, high-risk patients still have low survival rates. p21-activated kinase4 (PAK4) has been shown to regulate many cellular processes in cancer cells, including migration, polarization and proliferation. However, the role of PAK4 in neuroblastoma remains unclear. In the present study, we demonstrated that PAK4 was overexpressed in neuroblastoma tissues and was correlated with tumor malignance and prognosis. To investigate the function of PAK4 in neuroblastoma, we used a small-molecule inhibitor that targets PAK4, that is, PF-3758309. Our results showed that PF-3758309 significantly induced cell cycle arrest at the G1phase and apoptosis in neuroblastoma cell lines. Meanwhile, the inhibition of PAK4 by PF-3758309 increased the expression of CDKN1A, BAD and BAK1 and decreased the expression of Bcl-2 and Bax. In addition, we screened the target genes of PAK4 by PCR array and found that 23genes were upregulated (including TP53I3, TBX3, EEF1A2, CDKN1A, IFNB1 and MAPK8IP2) and 20genes were downregulated (including TNFSF8, Bcl2-A1, Bcl2L1, SOCS3, BIRC3 and NFKB1) after PAK4 inhibition by PF-3758309. Moreover, PAK4 was found to regulate the cell cycle and apoptosis via the ERK signaling pathway. In conclusion, the present study demonstrated, for the first time, the expression and function of PAK4 in neuroblastomas and the inhibitory effect of PF-3758309, which deserves further investigation as an alternative strategy for neuroblastoma treatment.=20
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  • Structure Mediation and Properties of Poly(l-lactide)/Poly(d-lactide) Blend Fibers

    Yang, Bo   Wang, Rui   Ma, Hui-Ling   Li, Xiaolu   Brunig, Harald   Dong, Zhenfeng   Qi, Yue   Zhang, Xiuqin  

    Poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) blend as-spun fibers (50/50, wt.%) were prepared by melt spinning. Structure mediation under temperature and stress and properties of poly(l-lactic acid)/poly(d-lactic acid)(PLLA/PDLA) as-spun fibers were investigated by wide-angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC). The results show that highly oriented stereocomplex (SC) crystals can be formed in PLLA/PDLA blend fibers drawn at 60 degrees C and annealed at 200 degrees C. However, at drawn temperature of 80 degrees C, only lower oriented SC crystals can be formed. For PLLA/PDLA blend fibers drawn twice at 60 degrees C (PLLA/PDLA-60-2), the crystallinity of SC crystals increases with annealing temperature in the range of 200 to 215 degrees C, while the degree of orientation decreases slightly. When the annealing temperature is 210 degrees C, the crystallinity and orientation of SC crystals in PLLA/PDLA-60-2 fibers reach 51% and -0.39, respectively. Moreover, PLLA/PDLA-60-2-210 fibers exhibit excellent heat-resistant property even at 200 degrees C. The results indicate that the oriented PLLA/PDLA blend fibers with high SC crystals content can be regulated in a short time.
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  • Signal-to-noise ratio analysis of all-fiber common-path optical coherence tomography RID A-3228-2010

    Li, Xiaolu   Han, Jae-Ho   Liu, Xuan   Kang, Jin U.  

    We present theoretical analysis and experimental verification of the signal to noise ratio (SNR) of a common-path interferometer-based optical coherence tomography (OCT) system. Based on fully integrated all-fiber implementation of a common-path time-domain OCT system, we derived the SNR of the system including the effect of beat noise, which turns out to be twice as large as the excess noise term. We verified the theoretical SNR through a series of experiments, utilizing both controlled phantom and biological samples such as a rat brain with tumor and a frog retina. The results showed that the source power and the reference reflectivity can be easily controlled to optimize the SNR of OCT imaging. We have also analyzed the effect of the fiber delays and the offset in the fiber autocorrelator of the common-path OCT system on the overall SNR. (C) 2008 Optical Society of America
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  • A novel hidden transmission of biometric images base on chaos and image content

    Li, Xiaolu   Qi, Zhi   Yang, Zhiqiang   Kong, Jun  

    This paper presents a novel hidden transmission method of biometric images base on chaos and image content to improve the security and secrecy of biometric verification. In our scheme, chaos is used to encrypt the watermark. The secret keys which called biokey are generated from the biometric image and used as the parameter value and initial condition of the chaotic map. The digital watermark embedded in the region of interest (ROI) of palmprint is used to recognize the paimprint has been destroyed or not and regarded as a user information index for verification. The watermarked ROI is hidden in the general public image using content-based steganography technology and transmitted secretly in case of attracting the attackers' attention. Our method can overcome the disadvantage of block-based steganographic techniques. Experimental results show that the security and performance of the proposed scheme are high.
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  • Target Elucidation by Cocrystal Structures of NADH-Ubiquinone Oxidoreductase of Plasmodium falciparum (PfNDH2) with Small Molecule To Eliminate Drug-Resistant Malaria

    Yang, Yiqing   Yu, You   Li, Xiaolu   Li, Jing   Wu, Yue   Yu, Jie   Ge, Jingpeng   Huang, Zhenghui   Jiang, Lubin   Rao, Yu   Yang, Maojun  

    Drug-resistant malarial strains have been continuously emerging recently, which posts a great challenge for the global health. Therefore, new antimalarial drugs with novel targeting mechanisms are urgently needed for fighting drug-resistant malaria. NADH-ubiquinone oxidoreductase of Plasmodium falciparum (PfNDH2) represents a viable target for antimalarial drug development. However, the absence of structural information on PfNDH2 limited rational drug design and further development. Herein, we report high resolution crystal structures of the PfNDH2 protein for the first time in Apo-, NADH-, and RYL-552 (a new inhibitor) bound states. The PfNDH2 inhibitor exhibits excellent potency against both drug -resistant strains in vitro and parasite-infected mice in vivo via a potential allosteric mechanism. Furthermore, it was found that the inhibitor can be used in combination with dihydroartemisinin (DHA) synergistically. These findings not only are important for malarial PfNDH2 protein-based drug development but could also have broad implications for other NDH2-containing pathogenic microorganisms such as Mycobacterium tuberculosis.
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  • Lipid Production from Dilute Alkali Corn Stover Lignin by Rhodococcus Strains

    He, Yucai   Li, Xiaolu   Ben, Haoxi   Xue, Xiaoyun   Yang, Bin  

    Biotransformation of lignin to lipids is challenging due to lignin's recalcitrant nature as a phenolic heteropolymer with a nonuniform structure that imparts rigidity and recalcitrance of plant cell walls. In this study, wild and engineered Rhodococcus strains (R. opacus PD630 and R jostii RHA1 VanA(-))with lignin degradation and/or lipid biosynthesis capacities were selected to establish fundamental understanding of the pathways and functional modules necessary to enable a platform for biological conversion of biomass-derived lignin to lipids. Degradation of lignin (39.6%, dry weight) was achieved by performing cofermentation with wild type R opacus PD630 and engineered R. jostii RHA1 VanA(-). Co-fermentation of these two strains produced higher lipids yield than single strain fermentation. Profiles of metabolites produced by the Rhodococcus strains while growing on alkali technical lignin suggested that lignin was depolymerized to reactive intermediates, such as vanillin, 2,3-dihydrobenzofuran, 2-methoxy-4-vinylphenol, and 3-hydroxy-4-methoxy-benzaldehyde, for lipid biosynthesis. Additionally, fatty acids (C13-C24), especially palmitic acid (C16:0; 35.8%) and oleic acid (C18:1; 47.9%), were accumulated in cells of R opacus PD630 and R jostii RHAl VanA(-) with lignin as the sole carbon source. Results suggest that the cofermentation strategy can depolymerize lignin into aromatics and promote the lipid production. The lipids produced during cofermentation of lignin by opacus PD630 and R jostii RHA1 VanA(-) showed promising potential in biofuel production.
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  • Community knowledge and experience of mosquitoes and personal prevention and control practices in Lhasa, Tibet.

    Liu, Xiaobo   Wan, Fangjun   Cirendunzhu   Cirenwangla   Bai, Li   Pengcuociren   Zhou, Lin   Baimaciwang   Guo, Yuhong   Dazhen   Xu, Junfang   Sang, Shaowei   Li, Xiaolu   Gu, Shaohua   Wu, Haixia   Wang, Jun   Dawa   Xiraoruodeng   Liu, Qiyong  

    Since 2009, great public attention has been paid in Lhasa City (Tibet, China) to mosquito bites and accompanying inflammatory complications. However, the potential contribution of knowledge levels, experiences, disease control and preventive practices (KEP) towards mosquitoes has not received much attention. To investigate community KEP concerning mosquitoes in Lhasa, a cross-sectional survey was undertaken in four sub-districts of urban Lhasa in 2012. Questionnaires were designed to collect information regarding socio-demographics and KEP concerning the harmful effects of mosquitoes on participants. The scoring for KEP was developed after consultation of literature. A total of 591 eligible questionnaires were examined. The majority of respondents were female (61.8%) with a mean age of 46 years. Nearly all of the respondents were of Tibetan nationality (97.4%) and living in registered native households (92.7%), who have less than primary school education. The averages of overall score, knowledge score, experience score, and practice score were 9.23, 4.53, 1.80, 2.90, respectively. The registered household with the highest overall score, knowledge score and practice score was non-native. Female subjects with monthly incomes between 1000 and 3000 RMB had higher experience scores. The correlation analysis revealed that significant positive linear correlations existed between knowledge and experience, knowledge and practices, and experience and practices towards mosquitoes. Past experiences with mosquitoes can result in a better knowledge of effective mosquito control practices in the present and the future. Though the average of overall scores related to mosquitoes is high among the participants in Lhasa, however, the knowledge about the ecological habits of mosquitoes should be strengthened. The findings in this study may help to develop strategies and measures of mosquito and mosquito-borne diseases in the future, not only in Lhasa, but also in similar altitude, latitude and longitude regions worldwide. =20
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  • Lab-built terrestrial laser scanner self-calibration using mounting angle error correction

    Li, Xiaolu   Li, Yunye   Xie, Xinhao   Xu, Lijun  

    Systematic errors generated from internal misalignments of a lab-built terrestrial laser scanner (TLS) need to be calibrated to improve the positional accuracy of point-cloud. Hence, an angle measurement error model was established by the ray-tracing method involving five types of mounting angle errors, which were estimated by two-face method and network method. Experimental results show that the two errors including mirror tilt error and vertical index offset error are regarded as main systematic errors for lab-built TLS, and consequently the positional accuracy of the point-cloud can be improved in horizontal and vertical directions. The proposed self-calibration method can be used for other TLS by adjusting the angle measurement error model. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
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