941 resultados para dye intercalation
A new fluorescent quantitative PCR-based in vitro neutralization assay for white spot syndrome virus
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A fluorescent quantitative PCR (FQ-PCR) assay utilizing SYBR green I dye is described for quantitation of white spot syndrome virus (WSSV) particles isolated from infected crayfish, Cambarus clarkii. For this assay, a primer set was designed which amplifies, with high efficiency and specificity, a 129 bp target sequence within ORF167 of the WSSV genome. Conveniently, WSSV particles can be added into the FQ-PCR assay with a simple and convenient method to release its DNA. To establish the basis for an in vitro neutralization test, primary cultures of shrimp cells were challenged with WSSV that had been incubated with a polyclonal anti-WSSV serum or with control proteins. The number of WSSV particles released from the cells after these treatments were assayed by FQ-PCR. This test may serve as a method to screen monoclonal antibody pools or recombinant antibody pools for neutralizing activity prior to in vivo animal experiments. (c) 2007 Elsevier B.V. All rights reserved.
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The RNA helicase Vasa is a germ cell marker in animals, and its homolog in vertebrates to date has been limited to bisexual reproduction. We cloned and characterized CagVasa, a Vasa homolog from the gibel carp, a fish that reproduces bisexually or gynogenetically. CagVasa possesses 14 RGG repeats and eight conserved motifs of Vasa proteins. In bisexually reproducing gibel carp, vasa is maternally supplied and its zygotic expression is restricted to gonads. By in situ hybridization on testicular sections, vasa is low in spermatogonia, high in primary spermatocytes, reduced in secondary spermatocytes, but disappears in spermatids and sperm. In contrast, vasa persists throughout oogenesis, displaying low-high-low levels from oogonia over vitellogenic oocytes to maturing oocytes. A rabbit anti-Vasa antibody (alpha Vasa) was raised against the N-terminal CagVasa for fluorescent immunohistochemistry. On testicular sections, Vasa is the highest in spermatogonia, reduced in spermatocytes, low in spermatids, and absent in sperm. In the ovary, Vasa is the highest in oogonia but persists throughout oogenesis. Subcellular localization of vasa and its protein changes dynamically during oogenesis. The aVasa stains putative primordial germ cells in gibel carp fry. It detects gonadal germ cells also in several other teleosts. Therefore, Cagvasa encodes a Vasa ortholog that is differentially expressed in the testis and ovary. Interestingly, the alpha Vasa in combination with a nuclear dye can differentiate critical stages of spermatogenesis and oogenesis in fish. The cross-reactivity and the ability to stain stage-specific germ cells make this antibody a useful tool to identify fish germ cell development and differentiation. (c) 2005 Wiley-Liss, Inc.
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Hybrid bulk heterojunction solar cells based on blend of poly(3-hexylthiophene) (P3HT) and TiO2 nanotubes or dye(N719) modified TiO2 nanotubes were processed from solution and characterized to research the nature of organic/inorganic hybrid materials. Compared with the pristine polymer P3HT and TiO2 nanoparticles/P3HT solar cells, the TiO2 nanotubes/P3HT hybrid solar cells show obvious performance improvement, due to the formation of the bulk heterojunction and charge transport improvement. A further improvement in the device performance can be achieved by modifying TiO2 nanotube surface with a standard dye N719 which can play a role in the improvement of both the light absorption and charge dissociation. Compared with the non-modified TiO2 nanotubes solar cells, the modified ones have better power conversion efficiency under 100 mW/cm(2) illumination with 500W Xenon lamp. (C) 2008 Elsevier B. V. All rights reserved.
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The transient optical nonlinearity of a nematic liquid crystal doped with azo-dye DR19 is examined. The optical reorientation threshold of a 25-mu m-thick planar-aligned sample of 5CB using a 50 ns pulse duration 532 nm YAG laser pulse is observed to decrease from 800 mJ/mm(2) to 0.6 mJ/mm(2) after the addition of 1 vol% azo dopant, a reduction of three orders of magnitude. When using a laser pulse duration of 10 ns, no such effect is observed. Experimental results indicate that the azo dopant molecules undergo photoisomerization from trans-isomer to cis-isomer under exposure to light, and this conformation change reorients the 5CB molecules via intermolecular coupling between guest and host. This guest-host coupling also affects the azo photoisomerization process.
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Background: Subretinal microphotodiode array (MPDA) is a type of visual prosthesis used for the implantation in the subretinal space of patients with progressive photoreceptor cell loss. The present study aimed to evaluate the effect of materials for MPDA on the viability, apoptosis and barrier function of cultured pig retinal pigment epithelium (RPE) cells.Methods: Primary culture of pig RPE cells was performed and 24 pig eyes were used to start RPE culture. The third passage of the cultures was plated on different materials for MPDA and MPDAs. The tetrazolium dye-reduction assay (MTT) was used to determine RPE cell viability. Flow cytometry was measured to indicate the apoptosis rates of RPE cells on different materials. RPE cells were also cultured on microporous filters, and the transepithelial resistance and permeability of the experimental molecule were measured to determine the barrier function.Results: The data from all the methods indicated no significant difference between the materials groups and the control group, and the materials tested showed good biocompatibility.Conclusions: The materials for MPDA used in the present study had no direct toxicity to the RPE cells and did not release harmful soluble factors that affected the barrier function of RPE in vitro.
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Naphthalocyanine-sensitized multi-walled carbon nanotube (NaPc-MWNT) composites have been synthesized through the pi-stacking between naphthalocyanine (NaPc) and carbon nanotubes. The resultant nanocomposites were characterized with a scanning electron microscope (SEM), a transmission electron microscope (TEM), and by UV - vis absorption and photocurrent spectra. The long-range ordering was observed in the NaPc - MWNT composites by using a TEM. The enhancement in the absorption intensity and the broadening of the absorption wavelength observed in the composite films, which were due to the attachment of NaPc on the MWNT surface, is discussed based on the measured UV - vis absorption spectra. Furthermore, the photoconductivity of the poly( 3-hexylthiophene)(PAT6) - NaPc - MWNT composite film was found to increase remarkably in the visible region and broaden towards the red regions. These new phenomena were ascribed to the larger donor/acceptor (D/A) interface and the formation of a biconsecutive D/A network structure, as discussed in consideration of the photoinduced charge transfer between PAT6 and NaPc - MWNT.
Valence band offset of MgO/TiO2 (rutile) heterojunction measured by X-ray photoelectron spectroscopy
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The valence band offset (VBO) of MgO/TiO2 (rutile) heterojunction has been directly measured by Xray photoelectron spectroscopy. The VBO of the heterojunction is determined to be 1.6 +/- 0.3 eV and the conduction band offset (CBO) is deduced to be 3.2 +/- 0.3 eV, indicating that the heterojunction exhibits a type-I band alignment. These large values are sufficient for MgO to act as tunneling barriers in TiO2 based devices. The accurate determination of the valence and conduction band offsets is important for use of MgO as a buffer layer in TiO2 based field-effect transistors and dye-sensitized solar cells.
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In this paper, bulk heterojunction photovoltaic devices based on the poly[2-methoxy-5-(3',7'-dimethyloctyloxy)- 1,4-phenylenevinylene] (MDMO-PPV):Bi2S3 nanorods hybrid material were present. To optimize the performance of the devices, the interface modification of the hybrid material that has a significant impact on the exciton dissociation efficiency was studied. An improvement in the device performance was achieved by modifying the Bi2S3 surface with a thin dye layer. Moreover, modifying the Bi2S3 surface with anthracene-9-carboxylic acid can enhance the performance further. Compared with the solar cells with Bi2S3 nanorods hybrid with the MDMO-PPV as the active layer, the anthracene-9carboxylic acid modified devices are better in performance, with the power conversion efficiency higher by about one order in magnitude.
Silver nanocrystals modified microstructured polymer optical fibres for chemical and optical sensing
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In-fibre chemical and optical sensors based on silver nanocrystals modified microstructured polymer optical fibres (MPOFs) were demonstrated. The silver nanocrystals modified MPOFs were formed by direct chemical reduction of silver ammonia complex ions on the templates of array holes in the microstructure polymer optical fibres. The nanotube-like and nanoisland-like Ag-modified MPOFs could be obtained by adjusting the conditions of Ag-formation in the air holes of MPOFs. SEM images showed that the higher concentration of the reaction solution (silver ammonia 0.5 mol/L, glucose 0.25 mol/L), gave rise to a tubular silver layer in MPOF, while the lower concentration (silver ammonia 0.1 M, glucose 0.05 M) produced an island-like Ag nanocrystal modified MPOF. The tubular Ag-MPOF composite fibre was conductive and could be directly used as array electrodes in electrochemical analyses. It displayed high electrochemical activity on sensing nitrate or nitrite ions. The enhanced fluorescence of dye molecules was observed when the island-like Ag-modified MPOF was inserted into a fluorescent dye solution. (C) 2007 Elsevier B.V. All rights reserved.
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A kind of optical pH sensor was demonstrated that is based on a pH-sensitive fluorescence dye-doped (eosin) cellulose acetate (CA) thin-film modified microstructured polymer optical fiber (MPOF). It was obtained by directly inhaling an eosin-CA-acetic acid mixed solution into array holes in a MPOF and then removing the solvent (acetic acid). The sensing film showed different fluorescence intensities to different pH solutions in a pH range of 2.5-4.5. Furthermore, the pH response range could be tailored through doping a surfactant, hexadecyl trimethyl ammonium bromide (CTAB), in the sensing film. (c) 2007 Optical Society of America.
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自20世纪60年代发展到现在,激光技术发展的速度十分惊人,应用的范围不断拓展,近年来随着有机/聚合物电致发光材料在有机发光二极管上的应用以及有机晶体管和有机太阳能电池的研制成功,科学家们开始了有机/聚合物材料放大自发发射和激光发射行为的研究。到目前为止,已经开发出了这种廉价、可以大面积成膜的、具有更广泛应用范围的有机/聚合物固体激光材料及光泵浦激光器。有机/聚合物激光器的出现不仅向传统激光理论提出了新的挑战,而且具有诸多潜在的应用价值。可以断言,在21世纪知识经济的大潮中,有机/聚合物激光器的研究必将推动传统学科的发展和新兴学科形成,也必将为人类带来巨大的经济效益。新的有机激光材料不断涌现、器件结构不断推陈出新、新的激发原理不断提出并得到修正已经成为有机/聚合物固体激光研究领域的三大特点。本论文进行了利用Förster能量传递对荧光染料DCJTB放大自发发射行为的优化、基于放大自发发射的红光染料DCJTB掺杂聚合物薄膜的白光发射、多孔结构对荧光染料放大自发发射行为的优化以及基于纳米结构的荧光染料DCJTB掺杂聚合物薄膜的激光行为等方面的研究工作,具体研究内容如下: 1、利用Förster能量传递理论,系统地研究了两种或三种染料共掺杂聚合物薄膜的放大自发发射(ASE)行为。研究表明,两种染料共掺杂显著改善了掺杂聚合物薄膜的ASE阈值、增益和损耗特性,而三种染料共掺杂,由于更多的Förster能量传递,使掺杂聚合物薄膜的ASE阈值、增益和损耗性能得到了进一步的改善。将Alq3和C545T两种绿光染料同时掺杂到DCJTB:PS中,通过利用Alq3和C545T同时的能量传递效应,已经使Alq3:C545T:DCJTB:PS薄膜的阈值、增益和损耗分别达到了0.007 mJ/pulse、52 cm-1和7 cm-1。 2、将红色荧光染料DCJTB掺杂到蓝色聚合物PFO中,通过控制DCJTB在PFO中的浓度,我们获得了具有放大自发发射的白光发射,当DCJTB在PFO的掺杂浓度为0.3%时显示了最好的白光ASE特性, 白光中DCJTB和PFO发射的阈值、增益和损耗分别达到了0.072 mJ pulse-1,0.035 mJ pulse-1;36.3 cm-1,22.35 cm-1和7.39 cm-1,15.88 cm-1。我们的结果表明,DCJTB掺杂聚合物PFO体系是实现ASE白光发射的有效方法,拓展了ASE的应用范围。 3、开发出了二维多孔SBA-15和三维TiO2反蛋白石光子晶体两种实现有机ASE有效发射的两种结构,通过利用有序结构的SBA-15的量子限域效应优化了蓝光染料C151的ASE阈值、增益和损耗特性,而通过利用三维TiO2反蛋白石光子晶体的量子限域效应,也使包埋其中的绿光染料C545T的ASE特性得到了明显改善。研究表明,无论是二维SBA-15多孔结构还是三维TiO2反蛋白石光子晶体结构,通过其量子限域效应都能很好地优化包埋其中的荧光染料的ASE特性,为进一步优化有机半导体的ASE特性提供了新的思路。 4、将聚苯乙烯纳米球分散到DCJTB:PS薄膜中和把DCJTB:PS薄膜旋涂在ZnO纳米柱阵列上两种方法,我们已经成功地研制出了多模随机有机激光发射器件。详细研究表明,多模随机有机激光发射特性显著地与聚苯乙烯纳米球的尺寸和浓度以及ZnO纳米柱的疏密程度密切相关,优化后的聚苯乙烯纳米球掺杂DCJTB:PS薄膜的阈值已经达到了0.06 mJ pulse-1cm-2,而ZnO纳米柱包埋DCJTB:PS薄膜的阈值达到了0.375 mJ pulse-1cm-2。我们的结果表明,聚苯乙烯纳米球和ZnO纳米柱都是实现随机有机激光的非常好的散射介质材料。
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近年来,由于有机和无机成分在纳米尺寸上的结合而带来的优异性能使得聚合物/蒙脱土纳米复合材料得到广泛关注。在诸多方法中,因能够使用传统的聚合物熔融挤出、共混等加工设备而无需额外的设备投资,投资低、见效快而且对周围环境没有污染等优点,熔融插层法倍受青睐。然而,通常认为亲油性聚合物无法直接插层蒙脱土,而需要预先用插层剂处理蒙脱土。大多数聚合物是亲油性的,这将大大增加制备材料的成本和工艺的复杂性,并因引入了小分子插层剂而有损材料性能的提高,从而阻碍了该技术的应用和推广。本文从理论上研究了插层剂用量对有机化蒙脱土及聚合物/蒙脱土纳米复合材料微观结构的影响,探索一种无需改性蒙脱土或用很少插层剂改性蒙脱土的制备聚合物/蒙脱土纳米复合材料的方法。1.系统地改变插层剂用量,制备不同的有机化蒙脱土。通过广角X射线衍射、热失重分析、索氏抽提器抽提、差热分析和付立叶红外分析等表征手段,研究了插层剂插层机理以及插层剂在蒙脱土层间的排列方式,为进一步研究有机化蒙脱土在聚合物树脂中的分散奠定基础。结果表明,插层剂插层蒙脱土机理和在蒙脱土层间的排列方式随着插层剂用量的变化而不同。2.用不同的亲油性聚合物熔融插层有机化蒙脱土以制备相应的聚合物/蒙脱土纳米复合材料。用广角嘴射线衍射仪和透射电子显微镜分析研究了蒙脱土在聚合物/蒙脱土纳米复合材料中分散状态。结果表明,随着插层剂用量的减少,蒙脱土片层在聚合物树脂中的分散逐渐由插层型过渡到剥离型,即减少改性蒙脱土时插层剂用量有利于蒙脱土在纳米尺寸上分散于聚合物树脂中。3.用不同的亲油性聚合物直接熔融插层未改性的蒙脱土,广角X射线衍射仪和透射电子显微镜表征结果表明,与蒙脱土片层有相互作用的亲油性聚合物能够直接熔融插层未改性的蒙脱土,获得剥离或插层型聚合物/蒙脱土纳米复合材料,这对于蒙脱土在聚合物改性中的应用具有重要的实际意义和理论意义。4.用共同的母料制备聚丙烯/酸配化聚丙烯/蒙脱土纳米复合材料和尼龙12/酸醉化聚丙烯/蒙脱土纳米复合材料,用广角X射线衍射仪和透射电子显微镜对比分析蒙脱土在聚合物中分散的差异,从而了解聚丙烯与酸配化聚丙烯之间的增容作用对蒙脱土在聚丙烯树脂中分散的影响;同时,用尼龙11和酸配化聚丙烯共插层蒙脱土制备聚丙烯/蒙脱土纳米复合材料,并探讨其增容机理。
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The photocatalytic degradation performance of photocatalysts TiO2 supported on 13-X, Na-Y, 4A zeolites with different loading content was evaluated using the photocatalytic oxidation of dyes direct fast scarlet 4BS and acid red 3B in aqueous medium. The results showed that the best reaction dosage of TiO2-zeolite catalysts is about 2 g/l and the photocatalytic kinetics follows first order for all supported catalysts. The photocatalytic activity order of the three series catalysts is 13X type >Y type >4A type. The physical state of titanium dioxide on the supports is evaluated by X-ray photoelectron spectra (XPS), powder X-ray diffraction (XRD), BET, and FTIR. (C) 2000 Elsevier Science Ltd. All rights reserved.
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染料废水成分复杂,色度高,是主要的环境污染源之一。应用微生物对染料废水脱色具有处理费用低和操作管理方便等优势,具有较好的发展前景。 本文采用筛选到一株短刺小克银汉霉(Cuuninghamella echinulata) KM3及一株红酵母(Rhodotorula sp.)YR-1分别对偶氮染料刚果红废水和酸性红废水进行了脱色研究,同时利用KM3及YR-1组成的复合菌种脱色体系对酸性红废水进行了脱色实验,为染料脱色真菌的应用奠定了基础。 KM3形成的菌丝球对多种染料具有较好脱色效果。KM3最适菌丝球形成条件:pH6-7、装液量90ml、孢子悬液浓度105个/ml (接种5ml)、摇床转速120rpm、培养温度30℃、培养时间72h;成球机理为凝聚型发育。KM3菌丝球对刚果红最佳脱色条件为:染料溶液初始pH值7.0,温度为33℃,摇床转速为120rpm。在刚果红50~200mg/l 浓度范围内, KM3菌丝球对刚果红吸附脱色动力学可用拟二级动力学方程描述。菌丝球对刚果红的吸附行为符合Langmuir和Freundlich 等温方程模型,Langmuir方程能更好的描述菌丝球对刚果红的吸附行为。丙酮对刚果红的解吸率最高,其解吸动力学过程符合二级动力学方程。将KM3应用在真菌生物滤床反应器中,在非灭菌和灭菌情况下接种孢子悬液后处理刚果红废水的过程中,均需长时间挂膜,处理效果一般。反应器中投加菌丝球后处理刚果红废水在3小时内达到92%以上的脱色效果。 YR-1对酸性红脱色机制属于降解脱色。YR-1对酸性红的最佳脱色培养条件为:初始pH 5.0、接种量5%、温度30℃;最佳碳源是葡萄糖,其次是蔗糖;最佳氮源是酵母膏或蛋白胨。在替换分批脱色实验和连续补料脱色实验中,脱色率一直保持在75%以上,显示YR-1在上述脱色体系中均具有良好适应性。 在三种复合菌种对酸性红的脱色体系中,体系Ⅲ(菌丝球与海藻酸钠固定化的酵母细胞混合培养)的脱色效果可达98%以上。对该体系而言,3种粒径固定化酵母小球(Ø1.1mm、1.8mm、3.1mm)中Ø1.8mm、3.1mm小球脱色率较为理想,而酵母细胞初始密度对脱色效果的影响不大。 KM3、YR-1分别具有处理刚果红废水和酸性红废水的应用前景,而KM3与YR-1联合应用对酸性红的脱色效果更好。