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51.
Definable surface chemistry is essential for many applications of microfluidic polymer systems. However, small cross-section channels with a high surface to volume ratio enhance passive adsorption of molecules that depletes active molecules in solution and contaminates the channel surface. Here, we present a one-step photochemical process to coat the inner surfaces of closed microfluidic channels with a nanometer thick layer of poly(ethylene glycol) (PEG), well known to strongly reduce non-specific adsorption, using only commercially available reagents in an aqueous environment. The coating consists of PEG diacrylate (PEGDA) covalently grafted to polymer surfaces via UV light activation of the water soluble photoinitiator benzoyl benzylamine, a benzophenone derivative. The PEGDA coating was shown to efficiently limit the adsorption of antibodies and other proteins to <5% of the adsorbed amount on uncoated polymer surfaces. The coating could also efficiently suppress the adhesion of mammalian cells as demonstrated using the HT-29 cancer cell line. In a subsequent equivalent process step, protein in aqueous solution could be anchored onto the PEGDA coating in spatially defined patterns with a resolution of <15 μm using an inverted microscope as a projection lithography system. Surface patterns of the cell binding protein fibronectin were photochemically defined inside a closed microfluidic device that was initially homogeneously coated by PEGDA. The resulting fibronectin patterns were shown to greatly improve cell adhesion compared to unexposed areas. This method opens for easy surface modification of closed microfluidic systems through combining a low protein binding PEG-based coating with spatially defined protein patterns of interest. 相似文献
52.
Morten B. Randers Jannick Marschall Tina-Thea Nielsen Andreas Møller Mette K. Zebis Peter Krustrup 《Sportwissenschaft》2018,48(2):211-217
Street soccer has been shown to be effective in improving cardiovascular and musculoskeletal fitness in homeless men, due to high heart rate (HR) and multiple intense actions. The purpose of this study was to investigate HR, movement pattern, rating of perceived exertion (RPE), flow and worry during street soccer for homeless women. Fifteen homeless women (30.3?±?5.0?years [± standard deviation, SD], 1.65?±?0.08?m, 65.1?±?11.0?kg, 5?±?4?years football experience) from three countries participated in 4?a-side street soccer games in Women’s Homeless World Cup 2015. Mean and peak HR were 174?±?7 and 188?±?10?beats per minute (bpm), respectively, and >160 bpm 76?±?23% of the playing time (11.1?±?2.6?min). Distance covered per minute was 68.6?±?8.9?m of which 82?±?14, 15?±?6 and 3?±?3% were covered with low- (0–9?km/h), moderate- (9–13?km/h) and high-speed (>13?km/h) running, respectively. The 43?±?5, 45?±?3 and 12?±?3% of the distance were covered running forward, sideways, and backward, respectively. Player Load was 9.2?±?1.7?arbitrary units (AU) per minute and the number of accelerations >1.5?ms–2 was 15.3?±?2.7 per minute. The score for flow was high (5.5?±?0.8), whereas rating of perceived exertion (RPE) values (4.8?±?2.5) and the score for worry (4.6?±?1.3) were moderate. Street soccer for homeless women elicits high HR and a movement pattern comparable and for some parameters even higher than street soccer and recreational football for homeless and untrained men. Street soccer may be a suitable training intervention for homeless women, and especially moderate RPE and high flow score speaks in favour of an expectation of high participation and adherence. 相似文献
53.
Christopher Cox Christina Dideriksen Tamar Keren-Portnoy Andreas Roepstorff Morten H. Christiansen Riccardo Fusaroli 《Child development》2023,94(6):1672-1696
This study compared the acoustic properties of 26 (100% female, 100% monolingual) Danish caregivers' spontaneous speech addressed to their 11- to 24-month-old infants (infant-directed speech, IDS) and an adult experimenter (adult-directed speech, ADS). The data were collected between 2016 and 2018 in Aarhus, Denmark. Prosodic properties of Danish IDS conformed to cross-linguistic patterns, with a higher pitch, greater pitch variability, and slower articulation rate than ADS. However, an acoustic analysis of vocalic properties revealed that Danish IDS had a reduced or similar vowel space, higher within-vowel variability, raised formants, and lower degree of vowel discriminability compared to ADS. None of the measures, except articulation rate, showed age-related differences. These results push for future research to conduct theory-driven comparisons across languages with distinct phonological systems. 相似文献