94 resultados para methylene diphosphate
Resumo:
合成了具有大π共轭性的对称型芴类衍生物9,9-二(2-乙基已基)-2,7-(2-(4-甲氧基)苯-2,1-乙烯基)芴(简写为MO-F1u—MO)。通过元素分析、质谱、紫外-可见光谱和红外光谱对其进行了表征。测试了该染料在乙腈、二氯甲烷、四氢呋喃和正己烷4种不同极性溶剂中的线性吸收光谱和单光子荧光谱。结果发现溶剂效应对吸收光谱和荧光光谱表现出不同程度的影响,对产生这些光谱行为的主要原因进行了讨论。
Resumo:
A novel wideband sensitive dry holographic photopolymer sensitized by rose bengal (RB) and methylene blue (MB) is fabricated, the holographic storage characteristics of which are investigated under different exposure wavelengths. The result shows that the sensitive spectral band exceeds 200 nm in visible light range, the maximum diffraction efficiency under different exposure wavelengths is more than 40% and decreases with the decrease of exposure wavelength, the exposure sensitivity is not change with the exposure wavelength. This photopolymer is appropriate for wavelength multiplexing or multi-wavelength recording in digital holographic storage.
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报道了一种新型、双染料共同敏化的光致聚合物材料,该材料以丙稀酰胺和双丙稀酰胺作为单体,聚乙烯醇为聚合物基质,两种染料曙红Y和亚甲基蓝作为光引发剂.实验结果表明,该材料在四种波长的激光照射下,其最大衍射效率均不低于25%,最大可达54.8%.通过采用多波长存储技术,分别利用四种不同波长的光在该聚合物膜上同一位置存储了四幅不同的图像,取得一定的效果.
Resumo:
Riboflavin is employed as the photosensitizer of a novel photopolyrner material for holographic recording, This material has a broad absorption spectrum range (More than 200nm) due to the addition of this dye. The experimental results show that our material has high diffraction efficiency and large refractive index modulation. The maximum diffraction efficiency of the photopolymer is about 56%. The digital data pages are stored in this medium and the reconstructed data page has a good fidelity, with the bit-error-ratio of about 1.8 X 10(-4). it is found that the photopolymer material is suitable for high-density volume holographic digital storage.
Resumo:
青蒿素是从中国传统药用植物青蒿(Artemisia annua L.)中提取的新型抗疟特效药。青蒿素在国际市场上供不应求,而青蒿植株中青蒿素的含量很低,因此如何提高青蒿素的产量成为近年来研究的热点。通过基因工程获得转基因青蒿高产株系是提高青蒿素产量的最有潜力的途径之一。 对不同基因型青蒿进行不同的激素浓度配比的比较研究,得到丛生芽诱导率较高、生根诱导率较高的激素配比,从而建立了青蒿高效再生体系。然后系统地分析了青蒿丛生芽诱导、丛生芽生长、丛生芽生根诱导对Kan的敏感性。对影响根癌农杆菌介导青蒿转化的转化效率的两个主要因素,即农杆菌类型和青蒿基因型,以及其它影响因素,即预培养时间、侵染液的组成、共培养的方式和时间进行比较研究,建立了根癌农杆菌介导的青蒿高效转化体系。本高效转化和再生体系的转基因植株的得率为4%至10%,而且转基因植株再生周期短,再生能力强。 通过基因工程,在青蒿高产株系中过量表达本实验室从青蒿中克隆的FPS基因,结果转基因青蒿中FPS的酶活性是非转基因青蒿的2-3倍;转基因青蒿的青蒿素含量最高可达0.9%(DW),是非转基因青蒿中青蒿素含量的1.34倍。这些结果进一步论证了FPS在青蒿素生物合成代谢中的调控作用。
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磷脂酰甘油(phosphatidylglycerol, PG)是类囊体膜(也叫光合膜)中唯一的一种磷脂。在蓝藻中,PG的合成途径为:磷脂酸(phosphatidic acid, PA)胞嘧啶双磷酸-二酰基甘油 (cytidine diphosphate diacylglycerol, CDP-DAG) 磷酸磷脂酰甘油 (phosphatidylglycerol phosphate, PGP)PG。其中最后一步反应是由PGP去磷酸化而生成PG,催化该反应的是PGP磷酸酶。然而迄今为止,PGP磷酸酶还没有在蓝藻和高等植物中得到克隆和鉴定。本工作在鱼腥藻Anabaena sp. PCC7120中通过将一个可能编码PGP磷酸酶的基因(alr1715)进行突变,获得缺失PG的突变体。与野生型相比,该突变体PG的含量降低了30%左右。突变后的蓝藻藻丝发黄、生长缓慢,叶绿素含量降低。整体细胞的光合作用活性、光系统II(photosystem II,PSII)的放氧活性以及PSII反应中心的光能转化效率显著下降,传递给PSII的激发能减少。
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Aim: To characterize the functional and pharmacological features of a symmetrical 1-pyrrolidineacetamide, N,N'-(methylene-di-4,1-phenylene) bis-1-pyrrolidineacetamide, as a new anti-HIV compound which could competitively inhibit HIV-1 integrase (IN) bindi
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A simple, rapid and sensitive on-line method for simultaneous determination of four endocrine disruptors (17 beta-estradiol, estriol, bisphenol A and 17 alpha-ethinylestradiol) in environmental waters was developed by coupling in-tube solid-phase microextraction (SPME) to high-performance liquid chromatography (HPLC) with fluorescence detection (FLD). A poly(acrylamide-vinylpyridine-NAP-methylene bisacrylamide) monolith, synthesized inside a polyether ether ketone (PEEK) tube, was selected as the extraction medium. To achieve optimum extraction performance, several parameters were investigated, including extraction flow-rate, extraction time, and pH value, inorganic salt and organic solvent content of the sample matrix. By simply filtered with nylon membrane filter and adjusting the pH of samples to 6.0 with phosphoric acid, the sample solution then could be directly injected into the device for extraction. Low detection limits (S/N = 3) and quantification limits (S/N = 10) of the proposed method were achieved in the range of 0.006-0.10 ng/mL and 0.02-0.35 ng/mL from spiked lake waters, respectively. The calibration curves of four endocrine disruptors showed good linearity ranging from quantification limits to 50 ng/mL with a linear coefficient R-2 value above 0.9913. Good method reproducibility was also found by intra- and inter-day precisions, yielding the RSDs less than 12 and 9.8%, respectively. Finally, the proposed method was successfully applied to the determination of these compounds in several environmental waters. (c) 2006 Elsevier B.V. All rights reserved.
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环境突发污染事故给人民生活、经济发展和生态环境造成重大影响,研究污染物泄漏造成河流突发污染事故的应急处理方法十分必要。本论文选取苯酚、苯胺和亚甲基蓝等典型污染物为实验对象,采用吸附容量大、密度与水接近的活性炭纤维(ACF)为吸附剂。在自制的河流模型中,研究了ACF以苯酚、苯胺和亚甲基蓝为典型污染物的吸附过程,考察了吸附剂投加量、污染物浓度、吸附剂比表面积、吸附剂投加方式、水流速度与水质等对吸附速率与吸附效果的影响。实验结果表明,ACF能以较快的速率吸附苯酚、苯胺和亚甲基蓝,吸附率都在95%以上; ACF投加量是影响吸附速率最重要的因素,当一次性投加ACF质量之比为 1:2:4时,吸附速率常数之比近似为1:2:4;污染物浓度对吸附速率的影响显著,浓度较低时吸附速率较高。苯酚初始浓度为7mg·L-1时,经过86分钟的吸附,处理后的浓度可以达到地表水Ⅴ类水中挥发酚的限值要求(0.1mg·L-1);在吸附11分钟左右追加适量的ACF,能够明显提高吸附速率;河水流速和河流中的天然有机物、浊度、河水硬度对ACF吸附都不产生显著影响,这说明ACF作为河流突发污染事故应急处理的吸附剂,有广泛的适应性。在实际河水中,ACF对苯酚的吸附过程与在模拟河水中相似,吸附效果显著。实验结果还表明,ACF对苯酚的吸附是放热反应,符合Freundlich模型和Langmuir模型。事故应急处理后,应该及时将吸附了污染物的ACF打捞上来,有利于进行后续处理。 Emergency environmental pollution accidents pose significant impacts on our living, economic development and ecological environment. The study on the approach of emergency control for the contingency caused by leakage of pollutants in rivers is very necessary. In the experiment, phenol, aniline and methylene blue were selected as representative pollutant and activated carbon fiber (ACF) was selected as adsorbent, which has strong adsorption capacity and similar density to water. In the self-made river model, the effects of ACF dosage, pollutant concentration, ACF surface area, ACF adding ways, water flow rate and water quality on adsorption courses were investigated. The experimental results showed that ACF could adsorb pollutant quickly and effectively. The ACF dosage was the most important factor that affected adsorption rate .When the ACF dosage rate was 1:2:4, the constants of adsorption rate was approximately 1:2:4. The effect of pollutant concentrations on the adsorption rate was notable. Faster adsorption rates were achieved at low pollutant concentrations. Phenol concentration reached the limits of volatile phenol in Category Ⅴ surface water (0.1 mg·L-1) after 86 minutes of adsorption with initial phenol concentration of 7 mg·L-1. After 11 minutes of adsorption, certain amount of ACF was added and the adsorption rate was improved significantly. River flow rate and water quality have little effect on the adsorption rate. The adsorption results obtained in actual river water were comparable with that in simulating river water. The results also showed that, ACF on the absorption of phenol is exothermic reaction, witch matched with the Freundlich model and the Langmuir model. After emergency treatment, the ACF absorbed pollutants should be promptly salvaged for follow-up treatment.
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Methyl radicals are generated by pyrolysis of azomethane, and the condition for achieving neat adsorption on Cu(110) is described for studying their chemisorption and reaction characteristics. The radical-surface system is examined by X-ray photoemission spectroscopy, ultraviolet photoemission spectroscopy, temperature-programmed desorption, low-energy electron diffraction (LEED), and high-resolution electron energy loss spectroscopy under ultrahigh vacuum conditions. It is observed that a small fraction of impinging CH3 radicals decompose into methylene possibly on surface defect sites. This type of CH2 radical has no apparent effect on CH3(ads) surface chemistry initiated by dehydrogenation to form active CH2(ads) followed by chain reactions to yield high-mass alkyl products. All thermal desorption products, such as H-2, CH4, C2H4, C2H6, and C3H6, are detected with a single desorption peak near 475 K. The product yields increase with surface coverage until saturation corresponding to 0.50 monolayer of CH3(ads). The mass distribution is, however, invariant with initial CH3(ads) coverage, and all desorbed species exhibit first-order reaction kinetics. LEED measurement reveals a c(2 x 2) adsorbate structure independent of the amount of gaseous exposure. This strongly suggests that the radicals aggregate into close-packed two-dimensional islands at any exposure. The islanding behavior can be correlated with the reaction kinetics and is deemed to be essential for the chain propagation reactions. Some relevant aspects of the CH3/Cu(111) system are also presented. The new results are compared with those of prior studies employing methyl halides as radical sources. Major differences are found in the product distribution and desorption kinetics, and these are attributed to the influence of surface halogen atoms present in those earlier investigations.
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The surface properties, porosities, and adsorption capacities of activated carbons (AC) are modified by the oxidation treatment using concentrated H2SO4 at temperatures 150-270 degreesC. The modified AC was characterized by N-2 adsorption, base titration, FTIR, and the adsorption of iodine, chlorophenol, methylene blue, and dibenzothiophene. The treatment of AC with concentrated H2SO4 at 250 degreesC greatly increases the mesoporous volume from 0.243 mL/g to 0.452 mL/g, specific surface areas from 393 m(2)/g to 745 m(2)/g, and acidic surface oxygen complexes from 0.071 meq/g to 1.986 meq/g as compared with the unmodified AC. The base titration results indicate that the amount of acidic surface oxygen groups on the modified AC increases with increasing the treatment temperatures and carboxyls and phenols are the most abundant carbon-oxygen functional groups. The carboxyl groups, COO- species, and hydroxyl groups are detected mainly for the sample treated at 250 degreesC. The mesoporous properties of the AC modified by concentrated H2SO4 were further tested by the adsorption of methylene blue and dibenzothiophene. The AC modified by concentrated H2SO4 at 250 degreesC has much higher adsorption capacities for large molecules (e.g., methylene blue and dibenzothiophene) than the unmodified AC but less adsorption capacities for small molecules (e.g., iodine). The adsorption results from aqueous solutions have been interpreted using Freundlich adsorption models.
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Glucose is an important regulator of cell growth and metabolism. Uridine diphosphate sugars (UDP-sugars), as the intermediate products of metabolism, play pivotal roles as precursors in the synthesis of complex carbohydrates and glycolipids as well as lectose. It is very important to study their metabolism in cells in clinical biochemistry. A capillary electrophoretic method has been developed for the analysis of UDP-sugars and nucleotides, By using an uncoated capillary (70cm x 50 mu m) and 20 mmol/L borax buffer (pH 9), 4 important UDP-sugars can be analyzed in 15 min at 22 kV with satisfactory precision and sensitivity. The developed method has been applied to analyze UDP-sugars concentrations in lymphocytes, fibroblasts and mesangial cells, and the results show it not only is much better than HPLC method, but also can be used to measure the energy charge of cells.