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821.
Crispin Szydzik Khashayar Khoshmanesh Arnan Mitchell Christian Karnutsch 《Biomicrofluidics》2015,9(6)
Microfluidic based blood plasma extraction is a fundamental necessity that will facilitate many future lab-on-a-chip based point-of-care diagnostic systems. However, current approaches for providing this analyte are hampered by the requirement to provide external pumping or dilution of blood, which result in low effective yield, lower concentration of target constituents, and complicated functionality. This paper presents a capillary-driven, dielectrophoresis-enabled microfluidic system capable of separating and extracting cell-free plasma from small amounts of whole human blood. This process takes place directly on-chip, and without the requirement of dilution, thus eliminating the prerequisite of pre-processed blood samples and external liquid handling systems. The microfluidic chip takes advantage of a capillary pump for driving whole blood through the main channel and a cross flow filtration system for extracting plasma from whole blood. This filter is actively unblocked through negative dielectrophoresis forces, dramatically enhancing the volume of extracted plasma. Experiments using whole human blood yield volumes of around 180 nl of cell-free, undiluted plasma. We believe that implementation of various integrated biosensing techniques into this plasma extraction system could enable multiplexed detection of various biomarkers. 相似文献
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823.
Tania Gallo Stuart Cormack Tim Gabbett Morgan Williams Christian Lorenzen 《Journal of sports sciences》2015,33(5):467-475
The relationship between external training load and session rating of perceived exertion (s-RPE) training load and the impact that playing experience, playing position and 2-km time-trial performance had on s-RPE training load were explored. From 39 Australian Football players, 6.9 ± 4.6 training sessions were analysed, resulting in 270 samples. Microtechnology devices provided external training load (distance, average speed, high-speed running distance, player load (PL) and player loadslow (PLslow)). The external training load measures had moderate to very large associations (r, 95% CI) with s-RPE training load, average speed (0.45, 0.35–0.54), high-speed running distance (0.51, 0.42–0.59), PLslow (0.80, 0.75–0.84), PL (0.86, 0.83–0.89) and distance (0.88, 0.85–0.90). Differences were described using effect sizes (d ±95% CL). When controlling for external training load, the 4- to 5-year players had higher s-RPE training load than the 0- to 1- (0.44 ± 0.33) and 2- to 3-year players (0.51 ± 0.30), ruckmen had moderately higher s-RPE training load than midfielders (0.82 ± 0.58), and there was a 0.2% increase in s-RPE training load per 1 s increase in time-trial (95% CI: 0.07–0.34). Experience, position and time-trial performance impacted the relationship between external training load and s-RPE training load. This suggests that a given external training load may result in different internal responses between athletes, potentially leaving individuals at risk of overtraining or failing to elicit positive adaptation. It is therefore vital that coaches and trainers give consideration to these mediators of s-RPE training load. 相似文献
824.
Hans-Ulrich Wagner 《Media History》2015,21(4):443-458
Following the end of the Second World War, the ideals of public service broadcasting that had first been exemplified by the BBC came to lay the groundwork for a new type of broadcasting system in Northern Germany. This led to intensive discussions between British Military Officers and their German counterparts about the principles of public service broadcasting. Repatriated Germans came to play a crucial role. Having worked for the BBC German Service during their years of exile, some of them helped to nurture a new generation of democratic journalists. Focusing on these men, this article reveals the difficulties in transferring and adapting public service ideals. Making use of a wide range of sources, we highlight the multifaceted roles of the repatriated Germans, as both intermediaries and transmitters of public service broadcasting. We show how many of them came to play a pivotal role in resisting pressure from conservative forces in West German society. 相似文献
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826.
Karen Christian 《International Journal of Science Education》2013,35(14):2231-2255
The central goal of the present exploratory study was to investigate the nature of the content-related interactions in study groups independently organized by college organic chemistry students. We were particularly interested in the identification of the different factors that affected the emergence of opportunities for students to co-construct understanding and engage in higher levels of cognitive processing. Our results are based on the analysis of in situ observations of 34 self-initiated study sessions involving over a 100 students in three academic semesters. The investigation revealed three major types of social regulation processes, teaching, tutoring, and co-construction in the observed study sessions. However, the extent to which students engaged in each of them varied widely from one session to another. This variability was mostly determined by the specific composition of the study groups and the nature of the study tasks in which they were engaged. Decisions about how to organize the study session, the relative content knowledge and conceptual understanding expressed by the participants, as well as the cognitive level of the problems that guided group work had a strong impact on the nature of student interactions. Nevertheless, group talk in the observed study groups was mostly focused on low-level cognitive processes. The results of our work provide insights on how to better support students' productive engagement in study groups. 相似文献
827.
This study examines how the teaching staff composition with respect to certification affects student achievement in compulsory Swedish schools. We apply an instrumental variable to estimate the effect of the share of non-certified teachers on student achievement (measured by grade point average, GPA). We find statistically significant negative effects on the GPA. The effect is stronger for students with highly educated parents. A one percentage point increase in the share of non-certified teachers is expected to decrease student's GPA by, on average, 1.8 standard deviations per year. This is a substantial effect considering the large differences in the shares of non-certified teachers across schools and municipalities. 相似文献
828.
This article discusses conceptual and empirical elements concerning the development of cognitive processes that function as precursors of reading, and their association with the acquisition of reading skills in an adult population participating in literacy courses. It connects emergent literacy research with historical–cultural and bioecological concepts. Subsequently, it focuses on the problem of the development of profiles of cognitive reading precursors. A sample of 63 Chilean adults was studied through a growth/learning curves approach. The study replicated previous results indicating the existence of three major profiles of these cognitive precursors. Together, these precursors are associated with significantly different learning curves beyond the effect of each precursor considered separately. In addition, it established a negative association between initial phonological awareness and the rate of reading acquisition during the course. It has been claimed that an individual's participation in specific cultural activities throughout his/her life influences the development of the precursors of reading. Based on a complementary biographical study of a subsample of participants, preliminary evidence is presented that supports this link. 相似文献
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830.
Informal learning is becoming a standard format in companies' training and development (T&D) activities. It requires a specific learning competence comprising cognitive, metacognitive, and motivational dimensions. In the present study, it was investigated whether learning-competence variables predict success in informal learning. Given the ageing of the workforce, we also explored age differences in learning competence in an online survey of 470 workers in three age groups (17–35, 36–50, and 51–65 years old) at a German mail-order company. Learning competence predicted success in informal learning independent of worker age, but was partially mediated by memory self-efficacy, which might induce second-order age effects under unfavourable T&D conditions. 相似文献