A hybrid microfluidic platform for cell-based assays via diffusive and convective trans-membrane perfusion     

Elizaveta Vereshchagina  Declan Mc Glade  Macdara Glynn  Jens Ducrée 《Biomicrofluidics》2013,7(3)

We present a novel 3D hybrid assembly of a polymer microfluidic chip with polycarbonate track-etched membrane (PCTEM) enabling membrane-supported cell culture. Two chip designs have been developed to establish either diffusive or convective reagent delivery using the integrated PCTEM. While it is well suited to a range of cell-based assays, we specifically employ this platform for the screening of a common antitumor chemotoxic agent (mitomycin C – MMC) on the HL60 myeloid leukemia cell line. The toxic activity of MMC is based on the generation of severe DNA damage in the cells. Using either mode of operation, the HL60 cells were cultured on-chip before, during, and after exposure to MMC at concentrations ranging from 0 to 50 μM. Cell viability was analysed off-chip by the trypan blue dye exclusion assay. The results of the on-chip viability assay were found to be consistent with those obtained off-chip and indicated ca. 40% cell survival at MMC concentration of 50 μM. The catalogue of capabilities of the here described cell assay platform comprises of (i) the culturing of cells either under shear-free conditions or under induced through-membrane flows, (ii) the tight time control of the reagent exposure, (iii) the straightforward assembly of devices, (iv) the flexibility on the choice of the membrane, and, prospectively, (v) the amenability for large-scale parallelization.  相似文献   

Effects of acute exercise,dehydration and rehydration on cognitive function in well-trained athletes     

Christopher Irwin  Nadia Campagnolo  Elizaveta Iudakhina  Gregory R. Cox  Ben Desbrow 《Journal of sports sciences》2018,36(3):247-255

This study investigated the effects of aerobic exercise, fluid loss and rehydration on cognitive performance in well-trained athletes. Ten endurance-trained males (25 ± 5 years; 175 ± 5 cm; 70.35 ± 5.46 kg; VO_2max, 62.95 ± 7.20 ml · kg.min^?1) lost ~2.5 ± 0.6% body mass via continuous cycling exercise at ~65% peak sustainable power output (60 min duration) before consuming different beverages (Water = W1 and W2, Sustagen Sport = SS, Powerade = PD) and food ad libitum on four separate occasions. Cognitive function using a four-choice reaction time task (CRT), body mass, fluid consumption volumes, urine samples and subjective ratings (alertness, concentration, energy) were obtained before and after exercise, and hourly during recovery (for 4 h). CRT latency was significantly reduced immediately after exercise compared to pre-exercise measures for all trials (W1 = ?16 ± 18 ms, W2 = ?22 ± 21 ms, PD = ?22 ± 22 ms, SS = ?19 ± 26 ms). However, this effect was short-lived with subsequent measures not different from pre-exercise values. No difference in CRT accuracy was observed at any time across all trials. Subjective ratings were not different at any time across all trials. Aerobic exercise, hypohydration or an interaction between these two may provide a small cognitive performance benefit. However, these effects are temporary and confined to the immediate post-exercise period.  相似文献   

Investigating the relationship between quality,format and delivery of feedback for written assignments in higher education     

Elizaveta Sopina 《Assessment & Evaluation in Higher Education》2015,40(5):666-680

Feedback can have a great impact on student learning. However, in order for it to be effective, feedback needs to be of high quality. Electronic marking has been one of the latest adaptations of technology in teaching and offers a new format of delivering feedback. There is little research investigating the impact the format of feedback has on quality of feedback and subsequently on student learning. This study sets out to investigate the impact paper-based and electronic methods of assignment submission and return have on students’ and markers’ perceived quality of feedback. Students and markers on an undergraduate course were asked to complete an anonymous online survey investigating their perceptions of quality, format and timeliness of feedback delivered electronically and on paper. The results showed that marking and providing feedback electronically was an acceptable method for markers, reporting improved speed and consistency of marking. There was no increase or decrease in satisfaction with the feedback received. Overall, electronic marking was found to be an acceptable method of delivery of feedback on written assignments by both students and markers. The findings of this study suggest that electronic marking can result in more timely feedback for students without impacting on quality.  相似文献