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61.
荧光探针标记操作简单且荧光的检测灵敏度比紫外-可见光谱等传统方法高3~4个数量级,故本实验借助荧光探针测定并分析不同聚合度壳寡糖单体在小鼠体内的吸收分布。制备异硫氰酸荧光素标记的壳寡糖单体并灌胃小鼠,借助小动物活体光学成像系统和荧光定量检测,分析聚合度2~5的壳寡糖单体在小鼠体内吸收分布的差异性。结果显示,荧光标记的壳寡糖单体灌胃小鼠1 h后,在小鼠体内的荧光信号达到最大分布,壳寡糖能吸收入血,并跨过血脑屏障分布到脑组织中,主要分布在肾和肝脏中,其次分布在心和脾,少量分布在肺和脑;不同聚合度壳寡糖单体在肾和肝的分布量与聚合度呈正相关,而在血清、心、脾、肺和脑中的峰值分布量为壳二糖最多,壳四糖其次,壳五糖最少。明确不同聚合度壳寡糖单体的体内吸收分布的差异性,对于壳寡糖功能活性的构效关系研究具有一定的指导意义,能为壳寡糖的功能活性机制研究以及加快壳寡糖在食品功能性食品的开发和应用提供参考。 相似文献
62.
Ayako Kitazawa Yukie Naka Hiroko Yamaguchi Norio Shimizu 《Journal of Bioscience and Bioengineering》2010,110(2):238-241
Nanoscale magnetic beads coated with nerve growth factor (NGF) allow us to accumulate neurons differentiated from mouse ES cells in a selected area of the culture plate surface using a magnet. Neurons with neurite outgrowths within a particular area expressed TrkA and incorporated beads in the soma. 相似文献
63.
64.
荧光素掺杂的溶胶凝胶SiO2/甲基硅油复合薄膜的制备和光谱特性 总被引:1,自引:0,他引:1
采用溶胶-凝胶(Sol-Gel)法制备了掺杂荧光素(FL)的SiO2/甲基硅油(MSO)复合薄膜,并且测定了这种薄膜的光谱特性.实验表明,荧光素掺杂的SiO2薄膜在350nm-450nm波长范围内激发,在520nm附近有最强的荧光发射峰;与常规SiO2膜相比较,SiO2/甲基硅油(MSO)复合薄膜的荧光发射强度可增加50%;在70℃下的加速老化实验表明,常规SiO2薄膜20天后开始出现严重的荧光猝灭现象,而复合膜放置一个月后荧光强度仅下降了15%. 相似文献
65.
66.
Emulsification is used to generate spherical particles or droplets of immiscible liquids, while block copolymer self-assembly yields a wide variety of nanostructures. The combination of these two methodologies can yield a variety of structures that would not be otherwise observed. The emulsification/solvent evaporation process provides a powerful means to direct block copolymer assembly. Various factors arising from the emulsification can direct the block copolymer assembly, such as confinement effects, interfacial tension, as well as other conditions. In this review, various emulsification techniques are discussed, such as oil-in-water emulsions, double emulsions, as well as the use of microfluidic devices. While emulsification-induced self-assembly may be used to control internal morphologies as well as overall shapes of particles, it also lends a convenient method for controlling surface structures. Examples of exotic structures that may be obtained through the use of these techniques will be described. Also, ways in which morphologies may be controlled using these methods will be discussed. 相似文献
67.
Abstract: We investigated the development of antioxidant activity relative to the change of pH, fluorescent intensity, ultraviolet (UV) absorbance (A294), browning (A420), and alpha‐dicarbonyl compounds in sugar‐amino acid Maillard reaction (MR) model systems comprising fructose, glucose, or ribose each with glycine (Fru‐Gly, Glu‐Gly, and Rib‐Gly) or lysine (Fru‐Lys, Glu‐Lys, and Rib‐Lys), respectively, which were heated at 121 °C for 5 to 90 min. For hexose models, the change in pH was shown to fit a second‐order polynomial regression with A294 and A420. Antioxidant activity was significantly and positively correlated with UV absorbance (r = 0.905, P < 0.001) and browning products (r = 0.893, P < 0.001) rather than with fluorescent products or the alpha‐dicarbonyl compounds. Type of sugar was most important in evoking a change in UV absorbance, browning, alpha‐dicarbonyl compounds, and antioxidant activity of MR products (MRPs). In conclusion, the antioxidant activity of MRPs in six model systems was more closely associated with products derived at the intermediate‐to‐late stages of the reaction and influenced mostly by the type of sugar. Practical Application: We report on the different factors and their interactions that are important for understanding the functional attributes of food components that comprise the generation of Maillard browning products and the associated antioxidant activities generated during high‐temperature food processing. 相似文献
68.
Purpose
To describe a new methodology for tear-film dynamics assessment by observing fluorescein decay rate over time and to understand the relationship between the newly defined tear fluorescein washout rate (TFWR) and other measures of the tear film behaviour.Methods
Forty subjects (24F/16M) aged (mean ± standard deviation) 31.8 ± 14.2 years volunteered for the study. It consisted of the review of medical history, McMonnies questionnaire (McMQ), slit lamp examination, and TFWR using a newly-developed fluorescein profilometry. The repeatability of TFWR measurements was assessed. TFWR estimates were contrasted against patient age, McMQ score, daytime, fluorescein tear film break-up time (FTBUT), tear meniscus height (TMH) and blink frequency.Results
Mean repeatability of the method was 28.13 ± 9.59%. The group mean TFWR was 39 ± 23% at 30-s mark after the beginning of measurements, ranging from 1.4% to 83%. This indicates that TFWR is highly subject-dependent. Statistically significant correlations were found between the percentage TFWR and McMQ score (r2 = 0.214, p = 0.001) as well as FTBUT (r2 = 0.136, p = 0.009). No statistically significant correlations were found between TFWR and age, daytime, TMH, and blink frequency.Conclusions
Fluorescein profilometry allows clinicians to follow dynamic changes in the tear film on the entire ocular surface and may be used for qualitative assessment of the tear film dynamics. 相似文献69.
Bing-Hung Chen Mei-Huei HungJeff Yi-Fu Chen Hsueh-Wei ChangMeng-Lung Yu Lei WanFuu Jen Tsai Tzu-Pin WangTzu-Fun Fu Chien-Chih Chiu 《Food chemistry》2012,132(2):968-974
Grapeseed extract (GSE) is a rich source of natural phenolic compounds and possesses various pharmacological activities, including antioxidant, anticarcinogenic and anti-inflammatory properties. However, effects of GSE on immunoglobulin (Ig) E-mediated allergic responses still remain elusive. In the present study, the effects of GSE on activation and degranulation of RBL-2H3 mast cells were investigated. GSE pretreatments (20-100 μg/ml) reduced IgE-antigen mediated release of β-hexosaminidase and histamine in RBL-2H3 cells. Additionally, GSE reversibly inhibited expression of FcεRI on RBL-2H3 cells. GSE treatments caused a significant elevation of intracellular cAMP levels, whereas the Ca2+ influx upon antigen stimulation was inhibited. Suppression on FcεRI expression together with decreased calcium uptake and increased cAMP level might be involved in attenuated degranulation of mast cells by GSE treatment. Our results suggest a possible pharmaceutical application of GSE in treating type I allergic diseases. 相似文献
70.
E. M. M. Manders 《Journal of microscopy》1997,185(3):321-328
Multicolour confocal microscopy has proven to be a successful technique for the analysis of the spatial relationship between different biological structures in the same preparation. However, when the positions of objects are compared, e.g. co-localization and distance measurements, any positional shift that arises between the colour components is clearly unacceptable. This paper presents a simple technique for measuring with high accuracy the positional shifts that occur between the colour components of an image. Multi-labelled microbeads were scanned using two or three different detection channels. The position of each microbead was calculated separately for each detection channel. In general, the two calculated positions of the same microbead (one for each channel) are slightly different. This difference is a measure of the positional shift between the colours. This method enables the measurement of shift with a high accuracy (20 nm), and it has been applied to images from several experiments. The results of these experiments will give the reader an impression of typical contributions of different effects (such as chromatic aberration, misalignment of optical components and inaccuracy of the scanning unit) on the amount of positional shift. 相似文献