Hydrodynamic self-focusing in a parallel microfluidic device through cross-filtration

The flow focusing is a fundamental prior step in order to sort, analyze, and detect particles or cells. The standard hydrodynamic approach requires two fluids to be injected into the microfluidic device: one containing the sample and the other one, called the sheath fluid, allows squeezing the sample fluid into a narrow stream. The major drawback of this approach is the high complexity of the layout for microfluidic devices when parallel streams are required. In this work, we present a novel parallelized microfluidic device that enables hydrodynamic focusing in each microchannel using a single feed flow. At each of the parallel channels, a cross-filter region is present that allows removing fluid from the sample fluid. This fluid is used to create local sheath fluids that hydrodynamically pinch the sample fluid. The great advantage of the proposed device is that, since only one inlet is needed, multiple parallel micro-channels can be easily introduced into the design. In the paper, the design method is described and the numerical simulations performed to define the optimal design are summarized. Moreover, the operational functionality of devices tested by using both polystyrene beads and Acute Lymphoid Leukemia cells are shown.     

Tracking of physical activity in pubertal boys with different BMI over two-year period

We examined the tracking of physical activity (PA) measured by accelerometers and subjective self- and parental reports in normal weight and overweight and obese pubertal boys over two-year period. In total, 156 boys with mean (±SD) age of 11.53 ± 0.76 at baseline and with mean age of 13.94 ± 0.74 at 2 year follow-up were studied. At baseline and approximately two years later, the boys completed self-report questionnaire and wore an accelerometer for seven consecutive days. On the basis of first year assessment’s body mass index (BMI), the children were grouped as normal weight and overweight and obese groups according to BMI cut-offs. Tracking correlations of objectively measured PA and subjectively measured PA were fairly similar across the 12–14 year-old-boys weight groups over two year period. Tracking correlations of objectively measured PA and subjectively measured PA were not significantly different over two-year period between both BMI groups. The results of the study show that pubertal boys objectively measured PA decreased over two-year period and so the boys started to be less active in their pubertal period.     

The use of spatial manipulation to examine goalkeepers’ anticipation

This study investigated whether anticipation and search strategies of goalkeepers are influenced by temporally and spatially manipulated video of a penalty. Participants were clustered into three groups depending on skill: goalkeepers (n = 17), field players (n = 20) and control group (n = 20). An eye tracker was worn whilst watching 40 videos of a striker kicking to four corners of a goal in random order. All 40 videos were temporally occluded at foot-to-ball contact, and the non-kicking leg of 20 videos was spatially manipulated. Results showed that goalkeepers had significantly better predictions than the two groups with no differences between the two testing conditions. According to effect size, the percentage of fixation location and viewing time of the kicking leg and ball were greater for the goalkeepers and field players group than the control group irrespective of testing conditions. The fixations on the kicking leg and ball in conjunction with comparable predictions between spatially manipulated and control conditions suggest that goalkeepers may not rely on the non-kicking leg. Furthermore, goalkeepers appear to use a global perceptual approach by anchoring on a distal fixation point/s of the penalty taker whilst using peripheral vision to obtain additional information.     

‘The Product of the Town Itself’: Community Representation and the Stanley Cup Hockey Challenges of the Kenora Thistles, 1903–1907

This case study of community representation in Canadian hockey analyzes media accounts of four Stanley Cup hockey series played by the Kenora Thistles between 1903 and 1907. It examines newspaper coverage of the Thistles hockey club as it moved from an amateur team represented by players with roots in their home community to a professional aggregation that included paid imports from outside the town. The essay explores the relationship between sport and civic identity during a key time of change in top-level hockey. The dominant narrative surrounding the Thistles portrayed players as true ‘members’ of the town of Kenora. Even after the turn to professionalism, narratives of small-town, amateur purity and close connections to the community characterized coverage of the Thistles as they pursued the Stanley Cup. At the same time, however, a growing emphasis on securing the personnel that could ensure victory led to praise for the club’s efforts to please its supporters, or ‘customers’. As a result, this study of notions of civic representation in early hockey provides insight into the process by which sports teams came to be viewed as symbolic representatives of their communities.     

Osmotically driven drug delivery through remote-controlled magnetic nanocomposite membranes

Implantable drug delivery systems can provide long-term reliability, controllability, and biocompatibility, and have been used in many applications, including cancer pain and non-malignant pain treatment. However, many of the available systems are limited to zero-order, inconsistent, or single burst event drug release. To address these limitations, we demonstrate prototypes of a remotely operated drug delivery device that offers controllability of drug release profiles, using osmotic pumping as a pressure source and magnetically triggered membranes as switchable on-demand valves. The membranes are made of either ethyl cellulose, or the proposed stronger cellulose acetate polymer, mixed with thermosensitive poly(N-isopropylacrylamide) hydrogel and superparamagnetic iron oxide particles. The prototype devices'' drug diffusion rates are on the order of 0.5–2 μg/h for higher release rate designs, and 12–40 ng/h for lower release rates, with maximum release ratios of 4.2 and 3.2, respectively. The devices exhibit increased drug delivery rates with higher osmotic pumping rates or with magnetically increased membrane porosity. Furthermore, by vapor deposition of a cyanoacrylate layer, a drastic reduction of the drug delivery rate from micrograms down to tens of nanograms per hour is achieved. By utilizing magnetic membranes as the valve-control mechanism, triggered remotely by means of induction heating, the demonstrated drug delivery devices benefit from having the power source external to the system, eliminating the need for a battery. These designs multiply the potential approaches towards increasing the on-demand controllability and customizability of drug delivery profiles in the expanding field of implantable drug delivery systems, with the future possibility of remotely controlling the pressure source.     

Core-shell hydrogel beads with extracellular matrix for tumor spheroid formation

Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since they may provide a better model of the tumor than conventional monolayer culture. Moreover, tumor cell interaction with the extracellular matrix can determine cell organization and behavior. In this work, a microfluidic system was used to form cell-laden core-shell beads which incorporate elements of the extracellular matrix and support the formation of multicellular spheroids. The bead core (comprising a mixture of alginate, collagen, and reconstituted basement membrane, with gelation by temperature control) and shell (comprising alginate hydrogel, with gelation by ionic crosslinking) were simultaneously formed through flow focusing using a cooled flow path into the microfluidic chip. During droplet gelation, the alginate acts as a fast-gelling shell which aids in preventing droplet coalescence and in maintaining spherical droplet geometry during the slower gelation of the collagen and reconstituted basement membrane components as the beads warm up. After droplet gelation, the encapsulated MCF-7 cells proliferated to form uniform spheroids when the beads contained all three components: alginate, collagen, and reconstituted basement membrane. The dose-dependent response of the MCF-7 cell tumor spheroids to two anticancer drugs, docetaxel and tamoxifen, was compared to conventional monolayer culture.     

心的中心地位:道家之间的论战

心与身体其他感觉器官的关系问题,备受先秦两汉所有重要思想流派的争议。众所周知,传统儒家认为心是主"情"的器官,并具有分析其他感官之间差异的能力1。对于孟子来说,"四端"学说就是关于"心"的内容,最为显著的是恻隐之心,它能促进人们德性的成长2。对于儒家来说,与其他自然的感觉器官相比,"心"是较为高级的。因为它不仅具有思考的能力,而且能评估人们所遇之事;而其他感知器官,仅仅是在于接触其他事物3。"心"比其     

Library as a Partner in Co-Designing Learning Spaces: A Case Study at Tampere University of Technology,Finland

This article presents a case of co-designed temporary learning spaces at a Finnish academic library, together with the results of a user-survey. The experimental development of the multifunctional spaces offered an opportunity for the library to collaborate with its parent organisation thus broadening the role of the library. Hence, library can be seen as a third player facilitating learning spaces. Additionally, the library's own expertise was strengthened through successful cooperation with the undergraduate students and other actors. The results support prior research, where studying in the library is target-oriented differing from other learning spaces in providing support and resources.     

Imagining the Journalist of the Future: Technological Visions of Journalism Education and Newswork

Digitization has resulted in great uncertainty for journalism, leading to disruption of business models, revenue streams, media distinctions, and production practices. This uncertainty has led to many articles, reports, blog posts, and general commentary discussing the future of both journalism and the skills required by journalists to succeed in this environment. This essay analyzes these discourses, focusing specifically on the nature of technology as the sole determiner of journalism’s future, with interventions aimed at journalism education and the structure of newswork. An idealized notion of the technologically adept journalist, ready to usher in digital stability, emerges as the object of these debates and, thanks in large part to the limited scope and ahistorical character of digital discourse, obscures more persistent, systemic critiques of technology and journalism.     

Flipping the classroom to teach systematic reviews: the development of a continuing education course for librarians

Objective:The researchers used the flipped classroom model to develop and conduct a systematic review course for librarians.Setting:The research took place at an academic health sciences library.Method:A team of informationists developed and conducted a pilot course. Assessment informed changes to both course components; a second course addressed gaps in the pilot.Conclusion:The flipped classroom model can be successful in developing and implementing a course that is well rated by students.