66 resultados para Aretino, Pietro, 1492-1556.


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含有功能侧基生物降解聚合物的制备在近几年中受到广大研究者的极大关注[1,2].目前已经通过环状碳酸酯与丙交酯(LA)和ε-己内酯(CL)等共聚的方法合成了带有羧基[3~5]和羟基[6,7]等的脂肪族聚酯,并在靶向载体、药物控释及组织工程方面得到了应用[2,8].但有关含侧链氨基的聚合物研究的报道很少,且主要集中在氨基酸NCA单体与LA的嵌段共聚方面[9,10],很少得到侧链氨基的无规共聚物.本文通过丙交酯(LA)与环状碳酸酯单体共聚的方法制备了一种侧链带有溴原子的脂肪族聚酯,并将溴原子用叠氮基团取代,通过Cu(Ⅰ)催化的Click反应将其氨基化,得到了侧链带有氨基的脂肪族聚酯.

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Blue, yellow and white light emissive LaOCl:Tm3+, LaOCl:Dy3+ and LaOCl: Tm3+, Dy3+ nanocrystalline phosphors were synthesized through the Pechini-type sol-gel process. X-Ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), photoluminescence (PL) and cathodoluminescence (CL) spectra were used to characterize the samples. Under UV radiation (229 nm) and low-voltage electron beam (0.5-5 kV) excitation, the Tm3+-doped LaOCl phosphor shows a very strong blue emission corresponding to the characteristic transitions of Tm3+ (D-1(2), (1)G(4) -> F-3(4), H-3(6)) with the strongest emission at 458 nm. The cathodoluminescent color of LaOCl:Tm3+ is blue to the naked eye with CIE coordinates of x = 0.1492, y = 0.0684. This phosphor has better CIE coordinates and higher emission intensity than the commercial product Y2SiO5:Ce3+.

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SrLa1-xRExGa3O7 (RE = EU3+, Tb3+) phosphor films were deposited on quartz glass substrates by a simple Pechim sol-gel method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy, field-emission scanning electron microscopy, photoluminescence spectra, and lifetimes were used to characterize the resulting films. The results of XRD indicated that the films began to crystallize at 700 degrees C and crystallized fully at 900 degrees C. The results of FNR spectra were in agreement with those of XRD. Uniform and crack-free films annealed at 900 degrees C were obtained with average grain size of 80 nm, root mean square roughness of 46 nm and thickness of 130 nm The RE ions showed their characteristic emission in crystalline SrLa1-xRExGa3O7 films, i.e., Eu3+ D-0-F-7(J) (J = 0, 1, 2, 3, 4), Tb3+5D4 -(7) F-J (J = 6, 5, 4, 3) emissions, respectively. The optimum concentrations (x) of Eu3+ and Tb3+ were determined to be 50, and 80 mol% in SrLa(1-x)RE(x)GGa(3)O(7) films, respectively.

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We synthesized a kind of gold nanoparticle protected by a synthetic lipid (didodecyidimethylammonium bromide, DDAB). With the help of these gold nanoparticles, hemoglobin can exhibit a direct electron transfer (DET) reaction. The formal potential locates at -169 mV vs. Ag/AgCl. Spectral data indicated the hemoglobin on the electrode was not denatured. The lipid-protected gold nanoparticles were very stable (for at least 8 months). Their average diameter is 6.42 nm. It is the first time to use monolayer-protected nanoparticles to realize the direct electrochemistry of protein.

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Nanometer-scale plowing friction and wear of a polycarbonate thin film were directly measured using an atomic force microscope (AFM) with nanoscratching capabilities. During the nanoscratch tests, lateral forces caused discrepancies between the maximum forces for the initial loadings prior to the scratch and the unloading after the scratch. In the case of a nanoscratch test performed parallel to the cantilever probe axis, the plowing friction added another component to the moment acting at the cantilevered end compared to the case of nanoindentation, resulting in an increased deflection of the cantilever. Using free-body diagrams for the cases of nanoindentation and nanoscratch testing, the AFM force curves were analyzed to determine the plowing friction during nanoscratch testing. From the results of this analysis, the plowing friction was found to be proportional to the applied contact force, and the coefficient of plowing friction was measured to be 0.56 +/- 0.02. Also, by the combination of nanoscratch and nanoindentation testing, the energetic wear rate of the polycarbonate thin film was measured to be 0.94 +/- 0.05 mm(3)/(N m).

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稀土毒理学以及稀土离子作为钙离子的探针的研究受到普遍关注,人们对稀土离子的生物化学性质进行了广泛研究.作者曾报到了金属离子对DPPC脂质体的极性头构象的影响.鞘磷脂是神经组织细胞膜的重要磷脂组分,和DPPC有相似的极性头.本文利用核磁共振结合Raman光谱研究了金属离子对鞘磷脂脂双层的极性头构象的影响.1 材料和方法

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桥联双环戊二烯基稀土化合物的合成已有不少报道。但双碳桥联双环戊二烯基稀土化合物至今未见任何报道。我们以(CH_3)_4C_2(C_5H_4MgCl)_2·4THF(Ⅰ)与无水三氯化稀土反应,通过控制两者的比例合成了两类双碳桥联二环戊二烯基稀土氯化物,(CH_3)_4C_2(C_5H_4)_2LnCl_2·Mg_2Cl_3·nTHF(Ⅱ)和(CH_3)_4C_2(C_5H_4LnCl_2·MgCl_2)_2·nTHF(Ⅲ),并对这两类化合物进行了表征,证实了这两类化合物的存在。

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乙腈是一种给电子能力很弱的配体。过渡金属乙腈阳离子型配合物是一类均相催化剂,可催化烯烃、环烯烃聚合、异构化等反应。1986年Thomas等将金属Eu和NOBF_(?)在CH_3CN中反应制得了合乙腈的稀土阳离子型配合物[Eu(CH_3CN)_3(BF_4)_3]_(?),并指出这一配

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BACKGROUND: Previously, tachyplesin gene (tac) has been successfully transferred into Undaria pinnatifida gametophytes using the method of microprojectile bombardment transformation. The objectives of this study were to compare and evaluate the performance of bubble-column and airlift bioreactors to determine a preferred configuration of bioreactor for vegetative propagation of transgenic U. pinnatifida gametophytes, and to then investigate the influence of light on vegetative propagation of these gametophytes, including incident light intensity, photoperiod and light quality to resolve the problems of rapid vegetative propagation within the selected bioreactor. RESULTS: Experimental results showed that final dry cell density in the airlift bioreactor was 12.7% higher than that in the bubble-column bioreactor under the optimal aeration rate of 1.2 L air min(-1) L-1 culture. And a maximum final dry cell density of 2830 mg L-1 was obtained within the airlift bioreactor using blue light at 40 mu mol m(-2) s(-1) with a light/dark cycle of 14/10 (h). Polymerase chain reaction (PCR) analysis indicated that genes (bar and tac) were not lost during rapid vegetative propagation within the airlift bioreactor. CONCLUSION: The airlift bioreactor was shown to be much more suitable for rapid vegetative propagation of transgenic U. pinnatifida gametophytes than the bubble-column bioreactor in the laboratory. The use of blue light allows improvement of vegetative propagation of transgenic U. pinnatifida gametophytes. (C) 2009 Society of Chemical Industry

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本论文采用扩增片段长度多态性(AFLP)技术对牙鲆Paralichthys olivaceus群体和夏鲆Paralichthys dentaus 群体进行了种群鉴定和遗传结构分析。共用8 对引物对两个群体(每个群体30 个个体)进行了分析。总共产生了379 个条带,条带大小在60-1000bp。牙鲆与夏鲆的遗传多态性分别为53.83%和22.22%。牙鲆群体的多态位点数显著低于夏鲆群体。牙鲆群体和夏鲆群体种的特异条带分别为27.3% 和 29.61%。两群体平均杂和度分别为0.0701 和 0.1556,香农氏多态指数分别为0.1044 和0.2387。群体内平均遗传距离分别为0.0705 (0.0214 到0.1377)和0.1656 (0.0629 到 0.2338),两群体间的平均遗传距离为0.6328。 AFLP 技术是进行种间群体结构分析的一个很好的分子标记方法,对牙鲆和夏鲆亲本群体进行遗传背景析为今后的杂交育种阐明种间杂交的遗传机理奠定基础。 在本论文中我们采用5×8 因子交配设计建立了牙鲆P. olivaceus(♀)× 夏鲆P. dentaus(♂)杂交家系,对生长相关性状的遗传力进行分析。所有家系都混合养殖在同一养殖池中,40 日龄,在养殖池中随机采集600 个个体,测量体长,体宽,体重等数量性状;然后提取杂交子代DNA 进行家系的鉴定。首先从牙鲆的微卫星中筛选了在牙鲆、夏鲆以及杂交子代扩增多态性较好的10 对微卫星引物(Po1, Po13, Po20, Po35, Po42, Po48, Po56, Po58, Po91, Poli 23TUF)。我们采用了三对引物对600 个个体进行了家系鉴定,共有400 多个体鉴定出自己的亲本,成功率达到80%以上。基于以上结果我们认为微卫星标记可以做为一个有效的标记来代替现实的物理标记,并且可以在子代的早期进行亲本的鉴定。 在养殖过程中,我们对自交和杂交家系生长状况进行了跟踪分析,在181刘清华 牙鲆(♀)×夏鲆(♂)分子遗传学及数量遗传学研究 博士学位论文II日龄之前杂交鲆体长和体重均为未表现出杂种优势,杂种优势率值始终为负值,但是绝对值在逐渐减小。从196 日龄之后杂交鲆杂种优势开始表现出来,并且在196 日龄之后杂种优势率显著的增加。256 日龄体长杂种优势率为14.29%,体重杂种优势率为59.78%, 271 日龄体长杂种优势率达到27.36%,体重杂种优势率为 102.32%。 本研究对杂交鲆在40 日龄的体长,体高、尾柄长、尾柄高,以及全长和体重的遗传力进行了估计,5 个性状的体长半同胞遗传力h2 S 为0.00146-0.719,5个性状的全同胞遗传力h2D 为0.00121-0.632,5 个性状的半同胞和全同胞的平均遗传力h2SD 为0.001335-0.6755。其中全长的遗传力最大。实验结果说明对早期幼鱼进行体长、体重等性状实施选育策略可能会显著影响后期杂交鲆的生长。

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2005年6月,中法国际合作在西太平洋海域执行IMAGES XII-MD147 Micro Polo1航次科学考察时,由法国极地研究所R/V Marine Dufresne极地考察船利用Calypso重力取样器于冲绳海槽南部钻取了34.2米长MD05-2908柱状样。本文利用AMS14C测年数据建立了该孔的年代模型,对该孔的浮游有孔虫动物群落进行了分析,并利用FP-12E浮游有孔虫转换函数和Q型因子分析方法对该孔浮游有孔虫数据进行了研究,对全新世以来的黑潮流系演化和古环境记录进行了讨论。 结果表明,中晚全新世存在着5次洪水爆发期,洪水爆发期与当时温暖气候相对应,而高海平面对洪水的爆发也产生了影响。进入全新世以来的6790~4000a B.P.期间,黑潮流一直有稳步增强的趋势,黑潮流始终位于冲绳海槽内;4000~3000a B.P.期间,黑潮强度减弱或者发生明显东偏,冲淡水影响增强;3000a B.P.以后黑潮强度逐渐增强,1650~0a B.P.为中晚全新世以来黑潮活动最强的时期,在600a B.P.和140a B.P.左右存在低值,黑潮强度短暂减弱。普林虫低值事件在MD05-2908孔中有很好的体现,对该事件进行了进一步定年,其发生时间为3900~2800a B.P.,持续时间为1100a,该事件的发生可能与东亚冬季风加强有关。 冲绳海槽中晚全新世气候变化可以分为四个阶段: 6790~4800a B.P.低温阶段,4800~4100a B.P.高温阶段,4100~2400a B.P.低温阶段,2400~0a B.P.波动高温阶段。通过与中国及世界其它地方对比可以识别出6.3~5.9、5.5、4.6~4.2、3.6~3.0、2.9~2.4、1.3~1.0、0.5~0.1ka B.P.六个降温事件,为全新世气候波动在深海高分辨率沉积记录中的响应提供了有力支持。该孔SST频谱分析结果显示,存在着3008a、1061a这种千年尺度的周期,以及215a、123a、103~107a、81~78a以及73~71a等周期,表明该孔SST变化与太阳活动强度是密切相关的。 中晚全新世以来,黑潮流在冲绳海槽逐步加强,到4000aB.P.左右达到最大,然后4000~3000a B.P.期间,黑潮强度明显减弱或者发生东偏,3000aB.P.以后,黑潮强度持续增强,在近1000aB.P.波动较大。 对冲绳海槽地区14个柱状样氧同位素以及P.obliquiloculata丰度进行研究,发现LGM以来,黑潮流可能仍然在冲绳海槽地区活动,并没有移出海槽外,但是由于其强度减弱,其流径发生了很大变化。