Enhanced single-cell printing by acoustophoretic cell focusing

Recent years have witnessed a strong trend towards analysis of single-cells. To access and handle single-cells, many new tools are needed and have partly been developed. Here, we present an improved version of a single-cell printer which is able to deliver individual single cells and beads encapsulated in free-flying picoliter droplets at a single-bead efficiency of 96% and with a throughput of more than 10 beads per minute. By integration of acoustophoretic focusing, the cells could be focused in x and y direction. This way, the cells were lined-up in front of a 40 μm nozzle, where they were analyzed individually by an optical system prior to printing. In agreement with acoustic simulations, the focusing of 10 μm beads and Raji cells has been achieved with an efficiency of 99% (beads) and 86% (Raji cells) to a 40 μm wide center region in the 1 mm wide microfluidic channel. This enabled improved optical analysis and reduced bead losses. The loss of beads that ended up in the waste (because printing them as single beads arrangements could not be ensured) was reduced from 52% ± 6% to 28% ± 1%. The piezoelectric transducer employed for cell focusing could be positioned on an outer part of the device, which proves the acoustophoretic focusing to be versatile and adaptable.     

Introducing novel approaches for examining the variability of individuals’ physical activity

Tudor-Locke and colleagues previously assessed steps/day for 1 year. The aim of this study was to use this data set to introduce a novel approach for the investigation of whether individual’s physical activity exhibits periodicity fluctuating round a mean and, if so, the degree of fluctuation and whether the mean changes over time. Twenty-three participants wore a pedometer for 365 days, recorded steps/day and whether the day was a workday. Fourier transform of each participant’s daily steps data showed the physical activity had a periodicity of 7 days in half of the participants, matching the periodicity of the workday pattern. Activity level remained stable in half of the participants, decreased in ten participants and increased in two. In conclusion, the 7-day periodicity of activity in half of the participants and correspondence with the workday pattern suggest a social or environmental influence. The novel analytical approach introduced herein allows the determination of the periodicity of activity, the degree of variability in activity that is tolerated during day-to-day life and whether the activity level is stable. Results from the use of these methodologies in larger data sets may enable a more focused approach to the design of interventions that aim to increase activity.     

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 Dutch motor skills assessment as tool for talent development in table tennis: a reproducibility and validity study

A motor skills assessment could be helpful in talent development by estimating essential perceptuo-motor skills of young players, which are considered requisite to develop excellent technical and tactical qualities. The Netherlands Table Tennis Association uses a motor skills assessment in their talent development programme consisting of eight items measuring perceptuo-motor skills specific to table tennis under varying conditions. This study aimed to investigate this assessment regarding its reproducibility, internal consistency, underlying dimensions and concurrent validity in 113 young table tennis players (6–10 years). Intraclass correlation coefficients of six test items met the criteria of 0.7 with coefficients of variation between 3% and 8%. Cronbach’s alpha valued 0.853 for internal consistency. The principal components analysis distinguished two conceptually meaningful factors: “ball control” and “gross motor function.” Concurrent validity analyses demonstrated moderate associations between the motor skills assessment’s results and national ranking; boys r = ?0.53 (P < 0.001) and girls r = ?0.45 (P = 0.015). In conclusion, this evaluation demonstrated six test items with acceptable reproducibility, good internal consistency and good prospects for validity. Two test items need revision to upgrade reproducibility. Since the motor skills assessment seems to be a reproducible, objective part of a talent development programme, more longitudinal studies are required to investigate its predictive validity.     

Argentina and the 1984 Los Angeles Olympics

The election of Raúl Alfonsín in October of 1983 represented the return of democracy to Argentina after more than seven years of a military dictatorship that left the country in a terribly distressed state. Since the dictatorship had joined the boycott of the 1980 Moscow Olympics led by the USA, for Argentina, the 1984 Los Angeles Olympics meant both coming back to the Olympic fold and the first such festival under the new democratic government. This paper explores Argentina's trajectory towards, and construction of, its participation in the country's first post-dictatorship Olympics. In doing so, this paper reveals why participation in the 1984 Los Angeles Olympics was not a priority for the incoming administration and why such participation was not conceived as a potential emissary capable of reaffirming on the global Olympic stage the hard fought, yet still emerging, democracy of Argentina. In addition, it reveals not only the determination of the Alfonsín administration to make his sport policy work but also its aspirations, complexity and ambiguities.     

Making It Fit: Reshaping Library Services and Spaces for Today's Students

University course assignments increasingly focus on group work and group projects to help students collaboratively discover more about their fields of study. The Thomas G. Carpenter Library realized the need to investigate means for reimagining itself to better accommodate today's researchers. The complex process of planning for the redesign of both services and space undertaken by the library is described and explained in this first of a planned series of articles.     

How Custom Agents Really Detect Lies

Research has found discrepancies among folk beliefs about lie detection, deception cue utility, and retrospective accounts of detected lies. Elite customs agents (N = 37) were surveyed regarding their overall beliefs about how to detect lies (general strategy), their opinions about best practices (best strategy), and about a successfully detected lie (actual strategy). Responses were coded in three nonexclusive broad categories: (a) behavioral cues, (b) communication content and evidence, and (c) interactive-questioning approaches. Behavioral cues, especially nonverbal cues, were listed most frequently as general beliefs. Opinions about the best approach were evenly split across the three categories. Communication content and evidence was the most frequently reported actual detection method and was mentioned in 97% of the responses. The results are discussed in relation to Truth-Default Theory and their implications for lie detection practice.