排序方式: 共有26条查询结果,搜索用时 4 毫秒
21.
Gulliksen A Solli LA Drese KS Sörensen O Karlsen F Rogne H Hovig E Sirevåg R 《Lab on a chip》2005,5(4):416-420
A general multipurpose microchip technology platform for point-of-care diagnostics has been developed. Real-time nucleic acid sequence-based amplification (NASBA) for detection of artificial human papilloma virus (HPV) 16 sequences and SiHa cell line samples was successfully performed in cyclic olefin copolymer (COC) microchips, incorporating supply channels and parallel reaction channels. Samples were distributed into 10 parallel reaction channels, and signals were simultaneously detected in 80 nl volumes. With a custom-made optical detection unit, the system reached a sensitivity limit of 10(-6) microM for artificial HPV 16 sequences, and 20 cells microl(-1) for the SiHa cell line. This is comparable to the detection limit of conventional readers, and clinical testing of biological samples in polymer microchips using NASBA is therefore possible. 相似文献
22.
West J Karamata B Lillis B Gleeson JP Alderman J Collins JK Lane W Mathewson A Berney H 《Lab on a chip》2002,2(4):224-230
Continuous flow microreactors with an annular microchannel for cyclical chemical reactions were fabricated by either bulk micromachining in silicon or by rapid prototyping using EPON SU-8. Fluid propulsion in these unusual microchannels was achieved using AC magnetohydrodynamic (MHD) actuation. This integrated micropumping mechanism obviates the use of moving parts by acting locally on the electrolyte, exploiting its inherent conductive nature. Both silicon and SU-8 microreactors were capable of MHD actuation, attaining fluid velocities of the order of 300 microm s(-1) when using a 500 mM KCl electrolyte. The polymerase chain reaction (PCR), a thermocycling process, was chosen as an illustrative example of a cyclical chemistry. Accordingly, temperature zones were provided to enable a thermal cycle during each revolution. With this approach, fluid velocity determines cycle duration. Here, we report device fabrication and performance, a model to accurately describe fluid circulation by MHD actuation, and compatibility issues relating to this approach to chemistry. 相似文献
23.
This study calculates the surface energy of polystyrene tissue culture plastic, silicon, silicon dioxide and indium tin oxide, all of which have applications in tissue culture. The adhesion molecules: collagen, fibronectin, poly-L-ornithine and poly-D-lysine, were coated onto these various surfaces, and the surface energy of the coated substrates calculated. Coating with fibronectin was found to produce a monopolar acidic surface while poly-D-lysine, poly-L-ornithine and collagen coatings were found to produce monopolar basic surfaces. The calculated surface energy components of the coated materials were then used to give a quantitative determination of the magnitude of their hydrophobicity. It was concluded that collagen, polylysine and polyornithine could provide a hydrophobic or hydrophilic surface depending on the underlying substrates they were coated on. The measurement obtained for fibronectin, unlike the other adhesion molecules, was independent of the underlying surface and remained hydrophobic on all substrates tested. Wetting experiments were carried out on the coated substrates, using the tissue culture medium Dulbeccos modified eagles medium, both containing and not containing serum proteins, and saline solution. These liquids that are commonly used in tissue culture, were then used to provide information how these liquids behave on various substrates coated with the adhesion molecules. Results show that fibronectin coated surfaces represent the most phobic surface for all three liquids. The findings of this study can be used in cell manipulation studies and provide a valuable data set for the biomedical and research industries. 相似文献
24.
The time-dependent chemisorption of 2-chlorophenol on a fumed silica surface was studied in situ from 200 to 500 degrees C using a temperature-controlled dosing cell and FTIR absorption spectroscopy. 2-Chlorophenol was found to chemisorb at isolated and geminal surface hydroxyl sites. 2-Chlorophenol chemisorption and subsequent surface oxidation resulted in a mixture of chlorophenolate and partial oxidation products, such as formates and acetates. The rates of chemisorption were measured, and the activation energy of adsorption was found to be 15 +/- 4 kJ mol(-1) for a fast, initial reaction and 22 +/- 2 kJ mol(-1) for a slower reaction at higher surface coverage. This work was motivated by the observation that combustion-generated fly ash mediates the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) at temperatures between 250 and 450 degrees C. Although transition metals such as copper are known to catalyze or mediate this reaction, silica is the major component of fly ash and chemisorption at higher concentration surface sites of silica must have a significant impact on the surface-mediated PCDD/F formation on fly ash surfaces. 相似文献
25.
On-chip definition of picolitre sample injection plugs for miniaturised liquid chromatography 总被引:1,自引:0,他引:1
O'Neill AP O'Brien P Alderman J Hoffman D McEnery M Murrihy J Glennon JD 《Journal of chromatography. A》2001,915(1-2):259-263
High-speed counter-current chromatography was applied to the preparative separation and purification of naphthopyranone glycosides from a crude 70% ethanolic extract of the capitula of Paepalanthus microphyllus. The solvent system used was composed of water-ethanol-ethyl acetate-hexane (10:4:10:4, v/v). This technique led to the separation of four different naphthopyranone glycosides in pure form in only 7 h. 相似文献
26.
Aasvang GM Øverland B Ursin R Moum T 《The Journal of the Acoustical Society of America》2011,129(6):3716-3726
The aim of this study was to explore and compare the effect of noise from railway and road traffic on sleep in subjects habitually exposed to nocturnal noise. Forty young and middle aged healthy subjects were studied with polysomnography (PSG) during two consecutive nights in their own bedroom. Noise measurements and recordings were conducted concurrently outside of the bedroom fac?ade as well as inside the bedroom of each participant. Different noise exposure parameters were calculated (L(p,A,eq,night), L(p,A,Fmax,night), and L(AF5,night)) and analyzed in relation to whole-night sleep parameters. The group exposed to railway noise had significantly less Rapid eye movement, (REM) sleep than the group exposed to road traffic noise. A significant association was found between the maximum level (L(p,A,Fmax,night)) of railway noise and time spent in REM sleep. REM sleep was significantly shorter in the group exposed to at least a single railway noise event above 50 dB inside the bedroom. These results, obtained in an ecological valid setting, support previous laboratory findings that railway noise has a stronger impact than road traffic noise on physiological parameters during sleep, and that the maximum noise level is an important predictor of noise effects on sleep assessed by PSG, at least for railway noise. 相似文献