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91.
基于功率型LED的在体整体荧光光学成像 总被引:1,自引:1,他引:1
用发光二极管(LED)替代常用的荧光激发光源汞灯,以实现基于LED的整体荧光光学成像(简称整体成像)。首先通过光谱计算分析,探讨了在不同波段与汞灯激发的荧光量相当时LED需要输出的光通量。以此为依据选择LED,构建了基于功率型LED的整体成像系统,用其动态监测绿色荧光蛋白(GFP)标记的肿瘤在裸鼠体内生长和药物治疗过程。实验表明,功率型LED可在类似于整体成像需要较大光功率的场合中应用。光源替代时,若两光源的光谱在选择的波段内分布不一样,则有必要考虑不同波长的光激发荧光效率差异的影响。 相似文献
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乙肝病毒衣壳蛋白成功组装成衣壳二十面体的过程是病毒前基因组RNA逆转录形成成熟DNA的必要步骤。衣壳结构的轻微改变或破坏能对病毒子代传播产生巨大影响。应用透射电子显微镜研究发现小分子抗病毒化合物(heteroaryldihvdropyrimidine,HAP)BAY41.4109在与衣壳蛋白二聚体摩尔浓度比达到1:2时,能干扰乙肝病毒衣壳蛋白组装成衣壳二十面体。在BAY41—4109的作用下,衣壳蛋白发生错误组装,形成不规则球体、平面片状结构和管状结构。应用图像处理技术对管状结构进行分析,发现它是衣壳蛋白重新装配形成的具有螺旋对称性的规则组装体,衣壳蛋白按六角晶格方式排列,其最小组成单位是衣壳蛋白的二聚体。 相似文献
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Linqing Li Megan E. Griebel Marina Uroz Saniya Yesmin Bubli Keith A. Gagnon Britta Trappmann Brendon M. Baker Jeroen Eyckmans Christopher S. Chen 《Advanced functional materials》2024,34(17):2309567
Although tissue culture plastic has been widely employed for cell culture, the rigidity of plastic is not physiologic. Softer hydrogels used to culture cells have not been widely adopted in part because coupling chemistries are required to covalently capture extracellular matrix (ECM) proteins and support cell adhesion. To create an in vitro system with tunable stiffnesses that readily adsorbs ECM proteins for cell culture, a novel hydrophobic hydrogel system is presented via chemically converting hydroxyl residues on the dextran backbone to methacrylate groups, thereby transforming non-protein adhesive, hydrophilic dextran to highly protein adsorbent substrates. Increasing methacrylate functionality increases the hydrophobicity in the resulting hydrogels and enhances ECM protein adsorption without additional chemical reactions. These hydrophobic hydrogels permit facile and tunable modulation of substrate stiffness independent of hydrophobicity or ECM coatings. Using this approach, it is shown that substrate stiffness and ECM adsorption work together to affect cell morphology and proliferation, but the strengths of these effects vary in different cell types. Furthermore, it is revealed that stiffness-mediated differentiation of dermal fibroblasts into myofibroblasts is modulated by the substrate ECM. The material system demonstrates remarkable simplicity and flexibility to tune ECM coatings and substrate stiffness and study their effects on cell function. 相似文献
96.
Inkjet Printing of Self‐Assembled 2D Titanium Carbide and Protein Electrodes for Stimuli‐Responsive Electromagnetic Shielding 下载免费PDF全文
Mert Vural Abdon Pena‐Francesch Joan Bars‐Pomes Huihun Jung Hemanth Gudapati Christine B. Hatter Benjamin D. Allen Babak Anasori Ibrahim T. Ozbolat Yury Gogotsi Melik C. Demirel 《Advanced functional materials》2018,28(32)
2D titanium carbides (MXene) possess significant characteristics including high conductivity and electromagnetic interference shielding efficiency (EMI SE) that are important for applications in printed and flexible electronics. However, MXene‐based ink formulations are yet to be demonstrated for proper inkjet printing of MXene patterns. Here, tandem repeat synthetic proteins based on squid ring teeth (SRT) are employed as templates of molecular self‐assembly to engineer MXene inks that can be printed as stimuli‐responsive electrodes on various substrates including cellulose paper, glass, and flexible polyethylene terephthalate (PET). MXene electrodes printed on PET substrates are able to display electrical conductivity values as high as 1080 ± 175 S cm?1, which significantly exceeds electrical conductivity values of state‐of‐the‐art inkjet‐printed electrodes composed of other 2D materials including graphene (250 S cm?1) and reduced graphene oxide (340 S cm?1). Furthermore, this high electrical conductivity is sustained under excessive bending deformation. These flexible electrodes also exhibit effective EMI SE values reaching 50 dB at films with thicknesses of 1.35 µm, which mainly originate from their high electrical conductivity and layered structure. 相似文献
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Managing the Public Sphere: Journalistic Construction of the Great Globalization Debate 总被引:2,自引:0,他引:2
W. Lance Bennett Victor W. Pickard David P. Iozzi Carl L. Schroeder Taso Lagos C. Evans Caswell 《The Journal of communication》2004,54(3):437-455
There is little consensus on what constitutes open, deliberative media discourse. We offer a simple, measurable, and comparative model based on 3 aspects of source and issue construction in news accounts: access, recognition, and responsiveness. The model is applied to coverage of 2001–2003 World Economic Forum (WEF) meetings and protests against the organization's role in global economic policies. Both demonstrators and WEF participants were granted news access, but WEF actors were recognized more formally and given greater input in news content, including ownership claims to many activist issue positions. Journalistic deference to the WEF communication agenda limited mutual responsiveness. The journalistic process systematically managed the debate about globalization on terms that favored elites over citizen-activists. 相似文献
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Zhanwei Zhou Yadong Liu Minghua Zhang Chenzi Li Ruoxi Yang Jing Li Chenggen Qian Minjie Sun 《Advanced functional materials》2019,29(39)
Protein‐based theranostic agents (PBTAs) exhibit superior performance in the diagnosis and therapy of cancers. However, the in vivo applications of PBTA are largely limited by undesired accumulation, penetration, or selectivity. Here, an ATP‐supersensitive protein cluster is fabricated for promoting PBTA delivery and enhancing magnetic resonance imaging (MRI)‐guided tumor photothermal therapy. Gd3+‐ and CuS‐coloaded small bovine serum albumin nanoparticles (GdCuB) are synthesized as the model protein with a size of 9 nm and are encapsulated into charge switchable polycations (DEP) to form DEP/GdCuB nanoclusters of 120 nm. In blood circulation, DEP/GdCuB significantly extends the half‐lifetime and thereby enhances the tumor accumulation of GdCuB. When the clusters reach the tumor site, the extracellular adenosine triphosphate (ATP) can effectively trigger the release of GdCuB, resulting in tumoral deep penetration as well as the activation of T1‐weighted MRI (r1 value switched from 2.8 × 10?3 to 11.8 × 10?3 m ?1 s?1). Furthermore, this delivery strategy also improves the tumoral photothermal therapy efficacy with the MRI‐guided therapy. The study of ATP‐activated nanoclusters develops a novel strategy for tumor deep penetration and on/off imaging of PBTA by size switchable technology, and reveals the potential for MRI‐guided therapy of cancers. 相似文献
100.
光电极是研究光遗传学不可或缺的工具之一。波长为460nm的蓝光可以对ChR2神经蛋白产生刺激,而波长为580nm的黄光可以刺激NpHR神经蛋白,对生物体的反应产生抑制。目前,蓝光波段的光电极具有很高的功率密度,可以满足光遗传学的研究,而黄光波段半导体发光器件的发光效率较低,因此对黄光波段的光电极研究较少。在蓝宝石衬底蓝光光电极研制的基础上,通过激发黄色荧光粉和量子点两种形式获得黄光,并通过沉积SiO2/TiO2分布式布拉格反射镜(DBR)有效滤除了蓝光波段的激发光,最后通过沉积Ag金属反射镜增强黄光信号,制备出荧光粉基和量子点基黄光光电极。与荧光粉基黄光光电极相比,量子点基黄光光电极具有更高的功率密度、更窄的光谱半宽和更薄的厚度。在1~10mA的注入电流下,量子点基黄光光电极的功率密度为4.46~15.37mW/mm2,满足刺激NpHR神经蛋白的要求。 相似文献