Jian Li

Beijing University of Posts and Telecommunications, Peping, Beijing, China

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Publications (35)23.93 Total impact

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    ABSTRACT: We propose a novel photonic downconversion method based on optical carrier reusing. In the proposed system, the phase modulator (PM) is placed between two narrowband fiber Bragg gratings (FBGs), which are designed to reflect the optical carrier and transmit the optical sidebands. The optical carrier is modulated in the PM in two directions and is not injected into the photodetector (PD). Thus, the utilization ratio of the optical carrier is enhanced and the power saturation in the PD is avoided. Consequently, the system gain can be improved. In addition, a 2×2 optical coupler is cooperated with a balanced PD behind these two FBGs. Resulting from the subtle design of the phase difference, gain is furthermore doubled and intensity noise can be reduced simultaneously. In the experiments, 29 dB gain improvement is measured compared with the traditional dual-series intensity modulators method. The noise floor is reduced by 12.1 dB.
    Optics Letters 09/2014; 39(17). · 3.39 Impact Factor
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    ABSTRACT: RNA-Seq, a high-throughput (HT) sequencing technique, has been used effectively in large-scale transcriptomic studies, and is particularly useful for improving gene structure information and mining of new genes. In this study, RNA-Seq HT technology was employed to analyze the transcriptome of yak ovary. After Illumina-Solexa deep sequencing, 26826516 clean reads with a total of 4828772880 bp were obtained from the ovary library. Alignment analysis showed that 16992 yak genes mapped to the yak genome and 3734 of these genes were involved in alternative splicing. Gene structure refinement analysis showed that 7340 genes that were annotated in the yak genome could be extended at the 5' or 3' ends based on the alignments been the transcripts and the genome sequence. Novel transcript prediction analysis identified 6321 new transcripts with lengths ranging from 180 to 14884 bp, and 2267 of them were predicted to code proteins. BLAST analysis of the new transcripts showed that 1200?4933 mapped to the non-redundant (nr), nucleotide (nt) and/or SwissProt sequence databases. Comparative statistical analysis of the new mapped transcripts showed that the majority of them were similar to genes in Bos taurus (41.4%), Bos grunniens mutus (33.0%), Ovis aries (6.3%), Homo sapiens (2.8%), Mus musculus (1.6%) and other species. Functional analysis showed that these expressed genes were involved in various Gene Ontology (GO) categories and Kyoto Encyclopedia of Genes and Genomes pathways. GO analysis of the new transcripts found that the largest proportion of them was associated with reproduction. The results of this study will provide a basis for describing the normal transcriptome map of yak ovary and for future studies on yak breeding performance. Moreover, the results confirmed that RNA-Seq HT technology is highly advantageous in improving gene structure information and mining of new genes, as well as in providing valuable data to expand the yak genome information.
    Science China. Life sciences. 06/2014;
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    ABSTRACT: Capripox viruses are economically important pathogens in goat and sheep producing areas of the world, with specific focus on goat pox virus (GTPV), sheep pox virus (SPPV) and the Lumpy Skin Disease virus (LSDV). Clinically, sheep pox and goat pox have the same symptoms and cannot be distinguished serologically. This presents a real need for a rapid, inexpensive, and easy to operate and maintain genotyping tool to facilitate accurate disease diagnosis and surveillance for better management of Capripox outbreaks. A LAMP method was developed for the specific differential detection of GTPV and SPPV using three sets of LAMP primers designed on the basis of ITR sequences. Reactions were performed at 62[degree sign]C for either 45 or 60 min, and specificity confirmed by successful differential detection of several GTPV and SPPV isolates. No cross reactivity with Orf virus, foot-and-mouth disease virus (FMDV), A. marginale Lushi isolate, Mycoplasma mycoides subsp. capri, Chlamydophila psittaci, Theileria ovis, T. luwenshuni, T. uilenbergi or Babesia sp was noted. RFLP-PCR analysis of 135 preserved epidemic materials revealed 48 samples infected with goat pox and 87 infected with sheep pox, with LAMP test results showing a positive detection for all samples. When utilizing GTPV and SPPV genomic DNA, the universal LAMP primers (GSPV) and GTPV LAMP primers displayed a 100% detection rate; while the SPPV LAMP detection rate was 98.8%, consistent with the laboratory tested results. In summary, the three sets of LAMP primers when combined provide an analytically robust method able to fully distinguish between GTPV and SPPV. The presented LAMP method provides a specific, sensitive and rapid diagnostic tool for the distinction of GTPV and SPPV infections, with the potential to be standardized as a detection method for Capripox viruses in endemic areas.
    BMC Microbiology 01/2014; 14(1):10. · 2.98 Impact Factor
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    ABSTRACT: A method to realize a highly linear microwave photonics link is proposed based on the dual-drive dual-parallel Mach-Zehnder modulator (MZM). The scheme theoretically eliminates third-order intermodulation distortion (IMD3) completely by taking all the sidebands in the optical spectrum that cause IMD3 into consideration. Without digital linearization and other optical processors, the method utilizes simple electrical signal phase control. Microwave signals are symmetrically single sideband modulated in the two MZMs. IMD3 suppression of approximately 30 dB is experimentally demonstrated, and the spurious-free dynamic range is improved by 12 dB·Hz<sup>2/3</sup>.
    Optics Letters 11/2013; 38(21):4285-7. · 3.39 Impact Factor
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    ABSTRACT: A low complexity scheme is proposed for direct detection orthogonal frequency division multiple access passive optical network, based on optical single sideband modulation and polarisation multiplexing. By utilising Hermitian symmetry mapping and Hilbert transformation, the hardware requirement is reduced. Theoretical expressions are presented to explain the cross-polarisation interference, and a channel estimation algorithm is proposed for polarisation crosstalk. In addition, system parameters are discussed to optimise the performance of the proposed scheme. Copyright © 2013 John Wiley & Sons, Ltd.
    Transactions on Emerging Telecommunications Technologies. 08/2013;
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    ABSTRACT: Abstract Abnormal epigenetic reprogramming of the donor nucleus after somatic cell nuclear transfer (SCNT) is thought to be the main cause of low cloning efficiency. Following SCNT, the donor nucleus often fails to express early embryonic genes and establish a normal embryonic pattern of chromatin modification. Therefore, in this study, we have attempted to improve epigenetic reprogramming of the donor nucleus and cloned embryos with Zebularine and Scriptaid. Yak fibroblasts were treated with 20 μM Zebularine alone or 20 μM Zebularine plus 0.5 μM Scriptaid for 24 h, whereas yak cloned embryos were treated exclusively with 0.5 μM Scriptaid for 12 h. There was no effect on cellular viability and proliferation after drug treatment. The treatment of fibroblasts with Zebularine or Zebularine plus Scriptaid increased histone acetylation of histone 3 lysine 9 (H3K9), but decreased the level of DNA methylation of Oct-4 and Sox-2 promoter regions. When donor cells were used after Zebularine plus Scriptaid treatment to reconstruct cloned embryos and then treated with Scriptaid, the developmental competence and cryosurvival of embryos were improved significantly. In addition, the relative expression of Oct-4 and Sox-2 were increased significantly. The expression levels of Dnmt-1 and Hdac-1 were significantly decreased when fibroblasts and cloned embryos were treated with Zebularine or Scriptaid. This work provides functional evidence that treatment with Zebularine and Scriptaid modifies the epigenetic status of yak fibroblasts, subsequently enhancing in vitro developmental potential and the quality of yak cloned embryos.
    Cellular reprogramming. 06/2013;
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    ABSTRACT: The local intestinal mucosa, the largest mucosal immune system in animals, plays an important role in resistance against intestinal pathogen infection. However, the molecular antiviral mechanisms of the intestinal mucosa remain poorly understood. In this study, we screened and identified differentially expressed transcripts in (PSV) porcine intestinal epithelial cells (IPEC-J2) infected with porcine sapelovirus using microarray analysis. A total of 2298 differentially expressed genes were screened at four time points during PSV infection. These genes were involved in numerous physical systems and molecular pathways, and particularly, some innate immune-associated pathways were significant. The results showed that large amounts of type I interferon were induced, and the related interferon effect pathway was activated when IPEC-J2 cells were infected with PSV. Three pathways of innate immune receptors, including Toll-like, NOD-like, and RIG-I-like receptors, were also activated. The antigen was then processed and presented through the MHCI and MHCII pathways. Interestingly, we found that the secretion network of IgA was activated in the early stage of PSV infection. Two exogenous and endogenous apoptosis pathways were also activated during PSV infection. The results revealed changes in gene transcription, particularly those of innate immune pathway genes that were associated with PSV infection in IPEC-J2 cells.
    Archives of Virology 02/2013; · 2.03 Impact Factor
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    ABSTRACT: Based on phase modulator, balanced photodetector, and fiber Bragg grating, we present a novel microwave downconversion method using direct-detection and post digital signal processing (DSP) to improve the gain and dynamic range of the link theoretically and experimentally. Both the reflection and transmission spectrum are used to increase the system gain. Experimental results show that this method increased the gain by 6 dB. In addition, the linearity of the system is improved by a simple strategy in the DSP module. This suppresses the third-order intermodulation by without sacrificing system gain. The experimental results show that the third-order limited spurious-free dynamic range increases by 5 dB.
    IEEE Photonics Technology Letters 01/2013; 25(20):2010-2013. · 2.04 Impact Factor
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    ABSTRACT: To improve spectrum efficiency (SE) of minimum-shift keying (MSK) in orthogonal frequency-division multiplexing (OFDM) system, MSK is extended to a continuous-phase frequency-shift-keying (CPFSK) scheme with multiple modulation indices h in this paper. We theoretically prove that the available h for the proposed multiple- h OFDM-CPFSK scheme is only the multiple of 1/2. Subsequently, a simple triple- h OFDM-CPFSK scheme with h = 0, 1/2, 1 is demonstrated as an example of the proposed multiple- h OFDM-CPFSK scheme. In our proof-of-concept experiment, a 10-Gb/s triple- h OFDM-CPFSK signal and a 10-Gb/s OFDM-MSK signal are successfully transported over 1000-km standard single-mode fiber. Electrical spectrum shows that the SE of the triple- h OFDM-CPFSK scheme is about twice as much as that of OFDM-MSK. Bit-error-rate performance of the 10-Gb/s triple- h OFDM-CPFSK signal and the 10-Gb/s OFDM-MSK signal after 300- and 1000-km transmissions demonstrates a robust performance of the triple- h OFDM-CPFSK scheme in long-haul high-speed transmission.
    IEEE Photonics Journal 01/2013; 5(6):7902607-7902607. · 2.36 Impact Factor
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    ABSTRACT: A simple photonic downconversion method using digital signal processing (DSP) in phase modulation link to suppress intermodulation distortion (IMD3) is proposed and experimentally demonstrated. The experimental results show that the IMD3 is suppressed by 17dB.
    Photonics Conference (IPC), 2013 IEEE; 01/2013
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    ABSTRACT: In microwave photonics links (MPLs), the multicarrier microwave signals are subjected to intermodulation distortion (IMD) and degrades the linearity of the MPL significantly. A linearization scheme is presented with an integrated parallel Mach-Zehnder modulator (MZM), without requiring optical/electrical filters and optical delays. In addition, to reduce the requirements on the electrical and optical components for the high-frequency applications, frequency doubling is designed in this linearization scheme. Theoretical expressions are presented to analyze this scheme. Experimental and numerical results show that the main IMD2 products are suppressed by more than 35 dB.
    IEEE Photonics Journal 01/2013; 5(4):5501108-5501108. · 2.36 Impact Factor
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    ABSTRACT: Goatpox is an economically important disease in goat and sheep-producing areas of the world. Many vaccine strategies developed to control the disease are not yet completely successful. Hairpin expression vectors have been used to induce gene silencing in a large number of studies on viruses. However, none of these studies has been attempted to study GTPV. In the interest of exploiting improved methods to control goat pox, it is participated that RNAi may provide effective protection against GTPV. In this study we show the suppression of Goatpox virus (GTPV) replication via knockdown of virion core protein using RNA interference. Four short interfering RNA (siRNA) sequences (siRNA-61, siRNA-70, siRNA-165 and siRNA-296) against a region of GTPV ORF095 were selected. Sense and antisense siRNA-encoding sequences separated by a hairpin loop sequence were designed as short hairpin RNA (shRNA) expression cassettes under the control of a human U6 promoter. ORF095 amplicon was generated using PCR, and then cloned into pEGFP-N1 vector, named as p095/EGFP. p095/EGFP and each of the siRNA expression cassettes (p61, p70, p165 and p296) were co-transfected into BHK-21 cells. Fluorescence detection, flow cytometric analysis, retro transcription PCR (RT-PCR) and real time PCR were used to check the efficiency of RNAi. The results showed that the ORF095-specific siRNA-70 effectively down-regulated the expression of ORF095. When Vero cells were transfected with shRNA expression vectors (p61/GFP, p70/GFP, p165/GFP and p296/GFP) and then infected with GTPV, GTPV-ORF095-70 was found to be the most effective inhibition site in decreasing cytopathic effect (CPE) induced by GTPV. The results presented here indicated that DNA-based siRNA could effectively inhibit the replication of GTPV (approximately 463. 5-fold reduction of viral titers) on Vero cells. This study demonstrates that vector-based shRNA methodology can effectively inhibit GTPV replication on Vero cells. Simultaneously, this work represents a strategy for controlling goatpox, potentially facilitating new experimental approaches in the analysis of both viral and cellular gene functions during of GTPV infection.
    Virology Journal 02/2012; 9:48. · 2.09 Impact Factor
  • Yan Lin, You Zhou, Jian Li
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    ABSTRACT: With the rapid development of real estate market, more and more explorers prefer to choose the market outsourcing to speed up marketing and realize the rapid return of the capital. Risk will happen inevitably in the process of outsourcing. This paper summarizes and analyzes the risk produced in the process of real estate market outsourcing by using the qualitative research method of induction and deduction based on the life-cycle theory, constructs risk assessment model by using the risk matrix and Voting Theory. Taking a typical real estate marketing outsourcing project for example, it applies risk matrix model to assess the key risk. The result of assessment is conformed to the realistic situation, which means risk matrix model has strong practicability and provides the basis to the further risk control.
    01/2011;
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    ABSTRACT: This study was carried out to investigate the biological characteristics of the foot-and-mouth disease (FMD) virus strain Asia-1 China/2005, which is responsible for the 2005 epidemic in China. The result showed that this strain is not host restricted, and could not only cause FMD in cattle and sheep but also in pigs by either inoculation or direct contact.
    Research in Veterinary Science 11/2008; 85(2):368-71. · 1.77 Impact Factor
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    ABSTRACT: The Single-granularity Automatically Switched Optical Network (SASON) has been extensively researched in recent years. Yet little work has been done in the research of integrating multi-granularity Optical Cross-Connects (OXCs) with ASON architecture, that is Multi-granularity ASON (MASON). In this paper, Generalised Multi-Protocol Label Switching (GMPLS) controlled MASON is evaluated through simulations. For the first time MASON is compared with SASON. The results reveal that MASON is more scalable and does better in cost saving. But its advantages are at the expenses of longer connection setup time, worse blocking performance and more sensitivity to the inaccuracy of the routing information. Copyright © 2007 John Wiley & Sons, Ltd.
    European Transactions on Telecommunications 01/2008; 19:39-46. · 1.05 Impact Factor
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    ABSTRACT: T-MPLS is regarded as one of the most important transport technologies in the next generation network, it a connection oriented packet transport technology develop from MPLS techniques, now defined by ITU-T SG13 & SG15. In this paper, we analyze the architecture of the transport MPLS networks, the most important building blocks for the modular design of the common T-MPLS equipment are introduced. And based on the functional blocks, a four-layer simulation T-MPLS node structure is developed. And the simulation environment is introduced. Many kinds of research can be done using this T-MPLS simulation tool, such as the research of the feasibility T-MPLS design, the inter-working between the T-MPLS and the PWE.
    Proc SPIE 12/2007;
  • Journal of Optical Communications 06/2007; 28(2):136-139.
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    ABSTRACT: p-cycle provides a new protection scheme which provides fast protection switching time as that in ring networks and high resource efficiency as that in mesh networks. Extensive research has shown that the concept of p-cycle can also be applied to Automatically Switched Optical Network (ASON), which is the direction of the next generation optical network. This paper proposes a novel dynamic p-cycle algorithm in ASON named Routing in Spare plus Protecting Capacity Dynamic p-cycle Algorithm (RSPC-DP). Different from traditional dynamic p-cycle algorithms, the proposed algorithm takes traffic forecast matrix into account, and it is capable of tracing the changes of network environment and dynamic traffic matrix on-line. Extensive simulation results show that the proposed algorithm outperforms the existing algorithms significantly.
    Proc SPIE 10/2006;
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    ABSTRACT: We study and test several P-Cycle generation algorithms from different strategies. The basic approach of P-Cycle algorithm is to identify an elementary cycle-set firstly, and then to search for improvements on this set through different strategies to create the final P-Cycle-set with higher efficiency. The P-Cycle generation algorithms which are presented in this paper are in terms of three aspects that are elementary cycle-set generation, expansion strategies and expansion times. At last simulation and analysis with these different algorithms will be presented.
    Proc SPIE 10/2006;
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    ABSTRACT: This paper focuses on the survival mechanisms against single link failure for optical QoS services in ASON (Automatically Switched Optical Network). The new protection and restoration methods and optical QoS services enabled by ASON also bring new requirements. Correspondingly, the component functions in ASON control plane, such as Connections Controller, Link Resource manager and Routing Controller are extended. According to the survival level of the QoS service requested, we divide the traffic into five types, viz. 1+1, 1:1, shared-mesh, rerouting and extra traffic. Optical QoS services and resource preemption are realized in our simulation platform. Extensive simulations are performed concerning failure localization time, failure recovery time, recovery success ratio and network resource utilization.
    Proc SPIE 10/2006;