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VEGF-specific siRNAs modified with 2′-deoxy effectively suppress VEGF expression and inhibit growth of nasopharyngeal carcinoma xenograft in a mouse model

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science china(life sciences) 2008年第2期51卷 104-110页

作者： CHEN ShanYi1, GAO GuoFeng1, CHEN Wei1, Lü Qing2, TANG Shen2, HUA Zhong2, YE WenBin2, GU DaYong2, WANG ShaYan1 & ZHANG YaOu2 1 shenzhen People’s Hospital, Clinical Medical College of Jinan university, shenzhen 518020, china 2.life science division, graduate school at shenzhen, tsinghua university, shenzhen 518055, china 1. shenzhen People’s Hospital Clinical Medical College of Jinan University Shenzhen 518020 China 2. life science division Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China

Vascular endothelial growth factor (VEGF) is up-regulated in the vast majority of human tumors. The up-regulation of VEGF not only plays important roles in tumor angiogenesis, but also provides a target for tumor treatment with small interfering RNA (siRNA) that targets VEGF; however, it is unclear whether a quite high up-regulation of VEGF will affect the efficiency of RNA interference strategies targeting VEGF. A high level expression of VEGF was found in CNE cells from a nasopharyngeal carcinoma cell line. In this study, we investigate whether VEGF-specific siRNAs can effectively suppress VEGF expression in CNE cells, and study the methods for the use of VEGF-specific siRNAs as potential therapeutic agents. CNE cells with high VEGF expression induced by hypoxia were transfected with VEGF-specific siRNAs. The expression of VEGF was effectively suppressed by VEGF-specific siRNAs, measured by ELISA, Western blot analysis and RT-PCR. Furthermore, experiments in nude mice bearing nasopharyngeal carcinoma xenograft were initiated 5 d after injection of CNE cells. VEGF-specific siRNAs were modified with 2′-deoxy, then injected into the tumors, and a liposome-mediated siRNA transfection system and ultrasound exposure were used to help delivery of the siRNAs. Tumor growth was reduced significantly after 3 weeks' treatment. These studies suggest that VEGF-specific siRNAs still can effectively suppress VEGF expression even in tumor cell lines with a relatively high level of VEGF expression, such as CNE, and VEGF-specific siRNAs modified with 2′-deoxy can be used as potential agents for tumor therapy.

关键词： small interfering RNA vascular endothelial growth factor (VEGF) nasopharyngeal carcinoma 2′-deoxy modification ultrasound

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Fluorescence fluctuation spectroscopy and its artifacts:simulations and tests

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science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 336-344页

作者： MENG Fanbo 1 , CHEN Bo 1 , LIU Guang 1 , DING Jianying 1 & MA Hui 2,1 1. Department of Physics and Key Laboratory of Atomic and Molecular Nano sciences, Ministry of Educa- tion, tsinghua university, Beijing 100084, china 2. graduate school at shenzhen, tsinghua university, shenzhen 518055, china 1. Department of Physics and Key Laboratory of Atomic and Molecular Nano sciences Ministry of Education Tsinghua University 100084 Beijing China 2. graduate school at shenzhen Tsinghua University 518055 Shenzhen China

Fluorescence fluctuation spectroscopy (FFS) technique is capable of monitoring changes in concentration, mass, size and structure of fluorescent-labeled bio-molecules in microscopic volume and is suitable for measuring biological interactions in living cells. FFS data may be affected by many experimental factors in complicated biological systems. Using a Monte Carlo approach, we generate fluorescence fluctuation data for different experimental systems. This approach helps to separate the contributions by different experimental factors in a complicated fluorescence fluctuation spectrum. It also helps to validate new theoretical models and new fitting formulations. We describe the algorithm of the simulation program and tests on its statistical performance. The program is then used successfully to study the effects of several experimental factors on FFS detection.

关键词： fluorescence fluctuation spectroscopy, fluorescence correlation spectroscopy, Monte Carlo simulation.

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Electric-stimulus rate encoding algorithm of Mandarin tonal information in cochlear implant

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Progress in Natural science:Materials International 2006年第12期16卷 1315-1321页

作者： GUAN Tian~1, GONG Qin~1 and YE Datian~2**(1. Department of Biomedical Engineering, tsinghua university, Beijing 100084, china 2. Research Center of Biomedical Engineering, graduate school at shenzhen, tsinghua university, shenzhen 518055, china) [a]Department of Biomedical Engineering Tsinghua University Beijing China [b]Research Center of Biomedical Engineering Graduate School at Shenzhen Tsinghua University Shenzhen China

The modern multi-channel cochlear implants usually extract and encode the temporal envelope cues. This kind of algorithms can hardly satisfy the users who speak tonal languages, such as Mandarin. Many studies have tried to enhance the recognition ability of Mandarin through encoding tonal information and made suggestions to frequency-modulate the fixed pulse-rate carrier with the extracted tonal information based on the rate-pitch theory in electric hearing. However, how to encode and deliver the tonal information such as F_0by changing electric-stimulus rate has not got further study in clinical electric-stimulus mode. The present paper focuses on this matter by piecewise calculating the appreciable electric-stimulus rates. Then an electric-stimulus encoding algorithm of Mandarin tone is brought forward and testified through acoustic simulations. Such conclusion can be drawn that this algorithm of electric-stimulus rate could convey tonal information well and help to enhance the Mandarin speech recognition ability.

关键词： cochlear implant tone fundamental frequency electric-stimulus rate.

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Generation of pancreatic islet cells from human embryonic stem cells

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science china(life sciences) 2009年第7期52卷 615-621页

作者： ZHANG DongHui1,2,JIANG Wei1,SHI Yan2 & DENG HongKui1,2 1 Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education,College of life sciences,Peking university,Beijing 100871,china 2 Laboratory of Chemical Genomics,shenzhen graduate school of Peking university,shenzhen 518055,china Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education College of Life Sciences Peking University Beijing 100871 China Laboratory of Chemical Genomics Shenzhen Graduate School of Peking University Shenzhen 518055 China

Efficiently obtaining functional pancreatic islet cells derived from human embryonic stem(hES) cells not only provides great potential to solve the shortage of islets sources for type I diabetes cell therapy,but also benefits the study of the development of the human pancreas and diabetes *** 2001,hES cells were reported to have the capacity to generate insulin-producing cells by spontaneous differentiation in *** then,many strategies(such as overexpression of key transcription factors,delivery of key proteins for pancreatic development,co-transplantation of differentiated hES cells along with fetal pancreas,stepwise differentiation by mimicking in vivo pancreatic development) have been employed in order to induce the differentiation of pancreatic islet cells from hES ***,patient-specific induced pluripotent stem(iPS) cells can be generated by reprogramming somatic *** cells have characteristics similar to those of ES cells and offer a new cell source for type I diabetes cell therapy that reduces the risk of immunologic *** this review,we summarize the recent progress made in the differentiation of hES and iPS cells into functional pancreatic islet cells and discuss the challenges for their future study.

关键词： human embryonic stem(hES) pancreatic islet cells differentiation induced pluripotent stem(iPS) cells

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Aging assessment of large generator insulation based on PD measurements

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Progress in Natural science:Materials International 2005年第11期15卷 1035-1043页

作者： YUE Bo, CHEN Xiaolin, CHENG Yonghong and XIE Hengkun (State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong university, Xi'an 710049, china graduate school at shenzhen, tsinghua university, shenzhen 518055, china Department of Electrical Engineering, tsinghua university, Beijing 100084, china) State Key Laboratory of Electrical Insulation and Power Equipment Xi''an Jiaotong University Xi''an 710049 China. graduate school Shenzhen Tsinghua University Shenzhen 518055 China. Department of Electrical Engineering Tsinghua University Beijing 100084 China

The statistical parameters of phase resolved partial discharge (PD) distribution and ultra-wideband (UWB) characteristics of PD pulse are proposed for aging assessment of large generator insulation. Multi-stress aging tests of the model generator stator bar specimens were performed and PD measurements were conducted using both digital PD detector with frequency ranging from 40 kHz to 400 kHz and UWB PD detector with bandwidth from 10 MHz to 3 GHz at different aging stages. The test results show that the skewness and UWB frequency characteristics of PD can be taken as the characterization parameters for aging assessment of generator insulation. Furthermore, the measurement results of real generator stator bars show that these methods based on statistical parameters and UWB characteristics of PD are prospective for aging assessment and residual lifetime estimation of large generator stator insulation.

关键词： partial discharge stator insulation multi-stress accelerated aging statistical parameters ultra-wideband aging assessment.

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Antisense expression of a rice cellular apoptosis susceptibility gene (OsCAS} alters the height of transgenic rice

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Progress in Natural science:Materials International 2007年第1期17卷 39-43页

作者： XU Chunxiao and HE Chaozu ( National Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of sciences, Beijing 100080, china graduate university of Chinese Academy of sciences, Beijing 100039, china shenzhen Laboratory of Superhybrid Rice Research, graduate school at shenzhen, tsinghua university, shenzhen 518055, china) [a]National Key Laboratory of Plant Genomics Institute of Microbiology Chinese Academy of Sciences Beijing China [b]graduate university of Chinese Academy of sciences Beijing China

Cellular apoptosis susceptibility (CAS) gene plays important roles in mitosis, development and export of importin a from the nucleus, but its function in plant is unknown. In this study, a rice CAS ortholog (OsCAS), which encodes a predicted protein of 983 amino acids with 62% similarity to human CAS, was identified. DNA gel blot analysis revealed a single copy of OsCAS in the rice genome. A 973 bp fragment at the 3' end of OsCAS cDNA was cloned from rice cDNA library and transferred into rice in the antisense direction under the control of CaMV 35S promoter via Agrobacterium-mediated transformation method, 105 transgenic lines were obtained. Expression of OsCAS was suppressed in the antisense transgenic lines as revealed by semi-quantitative RT-PCR. The antisense transgenic lines showed dwarf phenotypes. The results indicated that OsCAS was involved in culm development of rice.

关键词： antisense dwarf ortholog OsCAS rice.

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Effective use of the spectral information in speech processing of cochlear implant

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Progress in Natural science:Materials International 2007年第3期17卷 334-339页

作者： GUAN Tian, GONG Qin and YE Datian ( Joint Research Centre for Biomedical Engineering, Department of Electronic Engineering, The Chinese university of Hong Kong, Hong Kong, china Research Centre of Biomedical Engineering, graduate school at shenzhen, tsinghua university, shenzhen 518055, china) [a]Joint Research Centre for Biomedical Engineering Department of Electronic Engineering The Chinese University of Hong Kong Hong Kong China [b]Research Centre of Biomedical Engineering Graduate School at Shenzhen Tsinghua University Shenzhen China

Based on the results of the acoustic research on Mandarin, two novel algorithms using the spectral information in speech processing of cochlear implants are purposed and certified effectively by the spectral information of tonal language in acoustic simulation experiments. We bring forward novel algorithms conveying the spectral information based on the choices of the frequency bands. These new algorithms can not only improve the speech recognition ability of cochlear implant users in the noisy environments but also reduce the complexity of computing and the memory occupied, and make it more suitable to be carried out in clinical practice.

关键词： cochlear implant speech signal processing signal processing.

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A novel synthetic route for lifePO_4/C cathode materials by addition of starch for lithium-ion batteries

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Chinese Chemical Letters 2007年第2期18卷 237-240页

作者： Shao Hua Luo, Zi Long Tang, Jun Biao Lu, Zhong Tai Zhang State Key Laboratory of New Ceramics and Fine Processing, Department of Materials science and Engineering, tsinghua university, Beijing 100084, china graduate school at shenzhen, tsinghua university, shenzhen 518055, china [a]State Key Laboratory of New Ceramics and Fine Processing Department of Materials Science and Engineering Tsinghua University Beijing 100084 China [b]graduate school at shenzhen Tsinghua University Shenzhen 518055 China

lifePO4/Carbon composite cathode material was prepared using starch as carbon source by spray-pelleting and subsequent pyrolysis in N2. The samples were characterized by XRD, SEM, Raman, and their electrochemical performance was investigated in terms of cycling behavior. There has a special micro-morphology via the process, which is favorable to electrochemical properties. The discharge capacity of the lifePO4.C composite was 170 mAh g-1, equal to the theoretical specific capacity at 0.1 C rate. At 4 C current density, the specific capacity was about 80 mAh g-1, which can satisfy for transportation applications if having a more flat discharge flat.

关键词： Lithium-ion batteries Cathode material Carbon coated lifePO4 Spray-pelleting

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Positioning localities from spatial assertions based on Voronoi neighboring

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science china(Technological sciences) 2010年第S1期53卷 143-149页

作者： GONG YongXi 1,2,3,LI GuiCai 1,LIU Yu 2 & YANG Jian 1 1 shenzhen Key Lab of Recycling Economy,Peking university shenzhen graduate school,shenzhen 518055,china 2Institute of Remote Sensing and Geographical Information Systems,Peking university,Beijing 100871,china 3College of Urban and Environmental science,Peking university,Beijing 100871,china Peking Univ Shenzhen Grad Sch Shenzhen Key Lab Recycling Econ Shenzhen 518055 Peoples R China Peking Univ Inst Remote Sensing & Geog Informat Syst Beijing 100871 Peoples R China Peking Univ Coll Urban & Environm Sci Beijing 100871 Peoples R China

With the rapid development of Internet,much spatial information contained in non-structured or semi-structured documents is available on the World Wide *** such documents,localities are always textually described using spatial relationships and named places,instead of numerical ***,extracting positional information from locality descriptions is an important *** this paper,we bridge two aspects of locality descriptions,namely generating locality descriptions and positioning localities,and provide a method to compute probability density according to the selection probability of a reference object to describe the position of the target *** operation on uncertainty field is used to deal with locality description involving multiple reference *** metrics are introduced to measure the results of positioning *** choose the mixed selection probability function based on Euclidean distance and Voronoi stolen-area to compute probability density ***,we use three cases to demonstrate the proposed methods.

关键词： geographic information science positioning locality Voronoi neighboring probability density function

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The performance of ultra wideband acquisition system based on energy detection over IEEE 802.15.3a channel

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science china(Information sciences) 2011年第2期54卷 360-370页

作者： YANG ZhiHua, ZHANG QinYu, ZHANG NaiTong & WANG Ye Communication Engineering Research Center, shenzhen graduate school, Harbin Institute of Technology, shenzhen 518055, china 1. Communication Engineering Research Center Shenzhen Graduate School Harbin Institute of Technology Shenzhen 518055 China

In this paper, we propose a theoretical framework to analyze the performance of ultra wideband acquisition (UWB) system based on energy detection (ED) over IEEE 802.15.3a channel. The proposed framework enables to calculate probability density function (PDF) of square-sum of multipath components (MPCs) gain collected by receiver, and the averaged criteria. In particular, the expectation and variance of the sum variant characterized approximately by log-normal distribution are expressed in a closed form based on cluster point process. Moreover, the calculating methods of averaged criteria, through Markov chain model and signal flow graph, are clearly demonstrated for different applicable scenarios. The proposed framework is well consistent with simulation results with respect to each calculation method.

关键词： UWB energy detection unconditional criterion cluster point process

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