51 research outputs found

    Advances in flower genetic engineering

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    近十余年来,花卉基因工程取得了较大的进展,许多种花都已获得转基因植株,有的已进入商品化生产阶段.本文就基因工程在花卉方面的研究和应用作一综述.Important progress in flower genetic engineering, including improvement of the color, shape, flowering time and so on, has been made in the past ten years. Some transgenic flowers have been commercially released. Advances in this field have been due to the isolation and cloning of many important regarding genes and the development of a range of plant transformation technology, along with appropriate tissue culture techniques for regenerating whole plants.福建省科委资助项目(99-Z-115)

    Fine estimation of timing offset for OFDM

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    基于时域的帧同步估计算法在通过高斯信道和多径衰落信道时,其时间测度由于循环前缀的影响有峰值平台,难于准确的判定帧到达的时刻。文中提出了一种低复杂度的符号定时估计算法,利用简化的时间测度函数检测峰值来实现同步。分析了该算法的性能,并在各种信道中进行了性能分析,给出了了仿真结果。结果表明,该算法具有较高的精度和较低的计算复杂度。Symbol synchronization estimation based on time domain correlation is a problem of timing metric plateau in an AWGN channel and estimation error in multipath fading channel due to cyclic prefix.This paper proposes a novel low complex timing metric using a simple timing metric to achieve symbol synchronization.Performance of the algorithm is analyzed.The results show that the algorithm has high precision and low computation complexity.国家自然科学基金资助项目(60572106

    Advances in preparation of mesoporous silica nanoparticles and its use as different functional drug

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    近年来,有越来越多的文献报道关于介孔二氧化硅纳米粒(mesoporous silica nanoparticles,MSN)作药物载体的研究。本文结合近几年国内外的相关文献,介绍了由Mobli公司合成的M41S系列,圣巴巴拉大学合成的SBA系列,以及中空介孔二氧化硅纳米粒这3种最常见的MSN的特点及制备方法,并举例介绍了MSN作为药物速释载体的相关研究,同时从p H敏感型、热敏型、光响应型三方面介绍了MSN作为药物控释载体的研究。从相关研究结果可以看出,将MSN作为药物的载体,鉴于其独特的介孔孔径、可调节的纳米孔道结构、易于功能化修饰的表面等特点,可以实现对药物的速释、缓释及控释释放。由此可见,选择将MSN作为药物的载体具有广阔的应用前景。In the past a few years, mesoporous silica nanoparticles (MSN) have attracted more and more attention for their application in drug delivery. The recent relative literature was used for reference to introduce the characteristics and preparation of M41S series MSN (synthesized by Mobil Corporation), the SBA series MSN (synthesized by Santa Barbara University), and hollow mesoporous silica nanoparticles. Examples were presented to introduce the use of MSN as immediate drug delivery carrier. The use of MSN as controlled drug delivery carrier (CDDC) was illustrated via pH-responsive CDDC, temperature-sensitive CDDC, and light-triggered CDDC. MSN showed great properties in immediate/sustained/controlled drug delivery system, in view of their unique mesoporous pore diameter, adjustable nano-channel, and surface easily to be modified. The selection of MSN as drug carrier has a broad application prospect. ? 2017, Chinese Journal of New Drugs Co. Ltd. All right reserved.福建省科技计划重点项目(2013Y0074

    Preparation of mesoporous silica nanoparticles in different pore size and its use in the solidification of sirolimus loaded self-microemulsifying drug delivery system

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    研究制备了不同孔径的介孔二氧化硅纳米粒及西罗莫司自微乳。使用扫描电镜、透射电镜、小角度X-射线衍射、氮气吸附-脱附表征制得的介孔二氧化硅纳米粒,发现其为有序的纳米孔道结构,孔径分别为6.3、8.1和10.8 nm,通过粒径测定仪测得西罗莫司自微乳粒径为20.6±1.3 nm。通过搅拌法制备载西罗莫司自微乳介孔二氧化硅纳米粒。研究发现,当西罗莫司自微乳与介孔二氧化硅纳米粒质量比2∶1时为最佳比例,载药量约为0.83%,且固体粉末流动性良好。采用差示扫描量热法表明,西罗莫司以非晶体或无定形存在于载体材料中,重分散性良好。孔径大小对于载西罗莫司自微乳介孔二氧化硅纳米粒在250 m L水中2 h的释放终点并没有显著影响,但对于最初40 min释放结果影响较大。综上,介孔二氧化硅纳米粒有望成为一种新型的自微乳吸附剂。The mesoporous silica nanoparticles (MSN) in different pore size and sirolimus (SRL) loaded self-microemulsifying drug delivery system (SMEDDS) were prepared. The results in morphology were collected by scanning electron microscope, transmission electron microscope, small-angle X-ray diffraction, and N2 adsorption-desorption. The results showed that the prepared MSN has ordered nanochannels with a pore size of 6.3, 8.1, 10.8 nm, respectively. The particle size of SRL-SMEDDS were measured by particle sizing system, which was 20.6 ± 1.3 nm. The stirring method was developed to prepare SRL-SMEDDS-MSN. It was found that the optimal ratio of SRL-SMEDDS to MSN was 2: 1, while the drug loading rate was near 0.83%, and the flow properties of SRL-SMEDDS-MSN were of good condition. The differential scanning calorimetry results proving a molecular or amorphous dispersed state of SRL in MSN while the suspension experiment has shown great reconstitution properties of SRL-SMEDDS-MSN. There is no significant influence on maximum drug release rate of different pore size of SRL-SMEDDS-MSN in 250 mL water within 2 h, while the results of the first 40 min have an obvious difference. Above all, MSN might provide a new strategy for the solidification of SMEDDS.福建省科技计划重点资助项目(2013Y0074

    Phytoplankton biomarkers in surface seawater from the northern South China Sea in summer 2009 and their potential as indicators of biomass/community structure

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    生物标志物已被广泛应用于重建浮游植物生产力和群落结构变化。该方法假设之一是生标的含量可以反映表层海水的浮游植物生物量,但这个假设还缺乏现场观测的充分验证。对2009年冬季南海北部表层海水颗粒物中主要生标做了分析,利用其含量及比值研究浮游植物的生物量及群落结构的分布。生标含量表明硅藻、甲藻、颗石藻的高值区位于珠江口南部及广东沿岸,在陆坡区也有高值。生标比值显示硅藻在3个类群中的相对比例最高。其中,甲藻/硅藻比值高值区位于陆坡区,这与大洋水(黑潮)的入侵,带来大量暖水性甲藻有很大关系;颗石藻/硅藻比值总体趋势与生物量的分布相反,在近岸少数站位有高值,向外海逐渐增加,主要是因为颗石藻更适于寡营养盐的环境。生标结果所指示的生物量及群落结构的空间分布与前人的调查结果类似,为利用生标重建此区域的浮游植物生产力和群落结构变化提供了依据。Biomarkers have been widely used to reconstruct phytoplankton productivity based on the assumption that biomarker contents could reflect phytoplankton productivity in the surface seawater.However,this hypothesis has not been validated with modern survey.In this study,the contents and ratios of three phytoplankton biomarkers in the surface seawater of the northern South China Sea in winter 2009 were analyzed,to indicate spatial distributions of phytoplankton biomass and community structure.The results show high values for diatoms,dinoflagellates and coccolithophorids near the Pearl River Estuary and Guangdong coastal areas.The community structure indicates diatoms are the dominant phytoplankton species in winter.High values of dinoflagellate/diatom ratio occur near the slope area owing to intrusion of the Kuroshio,which favors the growth of dinoflagellates.The coccolithophorid/diatom ratio displays an increasing trend from the Pearl River Estuary to offshore region due to the advantage of coccolithophorids in oligotrophic environment,which is opposite to the productivity pattern of all biomarkers.These results are consistent with previous studies using phytoplankton cell and pigments,which provides support for the use of biomarker to reconstruct phytoplankton productivity and community structure in the SCS.国家重点基础研究发展计划项目(2007CB815934、2009CB421201);国家自然科学基金项目(40776029

    Function of a methyl-accepting chemotaxis protein Tlp1 in Azorhizobium caulinodans ORS571

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    【目的】考察茎瘤固氮根瘤菌中趋化基因簇上游的受体蛋白Tlp1编码基因的突变表型,初步探究其功能机理。【方法】利用同源重组和三亲本接合转移的方法构建突变株,在TY培养基中测定生长情况,半固体平板法观察趋化圈,刚果红固体培养基观察胞外多糖和次生代谢产物的分泌,乙炔还原法测定菌株的固氮酶活性。【结果】与野生型菌株相比,tlp1突变株的生长速率没有影响。在以甘油为碳源的L3半固体平板上突变株的趋化圈变小,其回补菌株能部分回补趋化能力。突变株的胞外多糖分泌与野生型没有区别,但其次生代谢产物黑色素出现的时间比野生型稍早。在固氮酶活性测定中,发现突变株酶活性明显比野生型降低,回补菌株能够部分回补。【结论】茎..

    ST段抬高型急性心肌梗死院前溶栓治疗中国专家共识

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    急性心肌梗死仍然严重威胁我国人民健康,在我国广大城乡地区,形势更为严峻[1,2]。及时救治急性心肌梗死患者,降低死亡率和保护心脏功能刻不容缓。鉴于我国的实际情况,院前溶栓治疗在大城市以外的城乡地区具有重要意义。为此,中国医师协会胸痛专业委员会及中国医学救援协会心血管急救分会专门组织有关专家制订了本共识,旨在帮助院前医疗急救人员对急性心肌梗死患者选择最佳

    Studies on TI Gene Transformation to the Tobacco Plants

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    实验用携带质粒pAM194/TI的根癌农杆菌LBA4404转化烟草,通过筛选,共获得35株卡那霉素抗性苗.GUS组织染色、PCR检测及抗虫试验表明胰蛋白酶抑制剂抗虫基因已经成功地整合进再生植株染色体基因组中,有些已正确表达.A sweet potato trypsin inhibitor(TI) gene was introduced into tobacco plants(Nicotiana tabaccu)by Agrobacterium tumefaciens-mediated leaf disc transformation.By plant tissue culturing and differentiation induction,35 kanamycin-resistant tobacco plant individuals were selected.GUS expression test and PCR amplification analysis showed that GUS reported gene and TI gene were successfully integrated into genome of all 35 independent kanamycin-resistant tobacco plant individuals and were normally expressed.In insecticidal bioassays of TI-transgenic tobacco plants,larval,the tobacco cutworm,was severely retarded while the control plants were vulnerable to it.This observation implied that Agrobacterium tumefaciens-mediated transformation and expression of sweet potato trypsin inhibitor can provide an efficient method for tobacco crop protection and production.福建省科技项目(99 Z 105)资

    Resolution-assignable DEM Generalization Based on

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    DEM的尺度效应研究需要分辨率连续变化的,空间定位基础一致的DEM数据作为数据源.针对这种需求,本文基于采样定理与分数进制小波变换,探讨了一种由较高分辨率DEM生成较低分辨率DEM的有效综合方法.首先基于采样定理分析了DEM分辨率与最高频率的关系,提出了通过降低DEM有效最高频率获得分辨率指定的DEM的新思路;然后基于该思路,探讨了分数进制小波变换自由精细的时频分解性能,以及对各分解部分的基于能量的阈值处理过程,进而实现了一种分辨率可指定的DEM综合方法;最后,对所指定的分辨率的合理性、空间定位的一致性、所生成DEM的综合效果进行了实验论证,并将所得DEM与由地形图派生的DEM以及由常规方法所得的DEM进行了对比分析,结果验证了该方法的有效性</span

    塔里木河下游荒漠河岸林群落最小取样面积

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    选择塔里木河下游退化程度不同的3个典型断面,采用相邻样方格子法,调查荒漠河岸林群落的种-面积关系,利用种-面积饱和曲线方程拟合的方法对群落的最小取样面积进行研究。结果表明,3个断面的群落最小面积分别设为1500、2000和2500m2可以满足精度为60%~80%的研究要求,满足精度为90%研究要求的群落最小面积分别为2500、3600和4500m2;群落最小面积呈现随植被退化程度加重而逐渐增大的趋势,而地下水埋深对群落最小面积的影响并不明显;种-面积饱和曲线针对塔里木河下游荒漠河岸林群落最小面积拟合的效果较好
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