28 research outputs found
Lifting Gate Polydimethylsiloxane Microvalves and Pumps for Microfluidic Control
No full textWe describe the development and characterization of pneumatically
actuated “lifting gate” microvalves and pumps. A fluidic
layer containing the gate structure and a pneumatic layer are fabricated
by soft-lithography in PDMS and bonded permanently with an oxygen
plasma treatment. The microvalve structures are then reversibly bonded
to a featureless glass or plastic substrate to form hybrid glass-PDMS
and plastic-PDMS microchannel structures. The break-through pressures
of the microvalve increase linearly up to 65 kPa as the closing pressure
increases. The pumping capability of these structures ranges from
the nanoliter to microliter scale depending on the number of cycles
and closing pressure employed. The micropump structures exhibit up
to 86.2% pumping efficiency from flow rate measurements. The utility
of these structures for integrated sample processing is demonstrated
by performing an automated immunoassay. These lifting gate valve and
pump structures enable facile integration of complex microfluidic
control systems with a wide range of lab-on-a-chip substrates
Conceptual framework of active transportation and health.
No full textConceptual framework of active transportation and health.</p
Number of deaths (95% confidence intervals) avoided or postponed per year and Number of deaths avoided or postponed per year per 100,000 travellers who shifted modes (95% confidence intervals).
No full textNumber of deaths (95% confidence intervals) avoided or postponed per year and Number of deaths avoided or postponed per year per 100,000 travellers who shifted modes (95% confidence intervals).</p
Sensitivity analysis. Number of deaths avoided or postponed per year by 100,000 travellers who shifted modes.
No full textA: Cyclist increment; B: Pedestrians increment. “Linear RR for PA”: Using a linear relative risk function for physical activity (for cycling or walking) as reported by kahlmeier S, et al, 2011; “50% of the trips coming from car trips”: Assume that half of the trips substituted in each scenario come from car trips; “Safety in numbers”: Assuming a fatal accident reduction associated with the increment of the number of pedestrians or cyclist; “Fatal accident risk of the reference city”: Assuming a fatal accident risk similar to the reference city for the scenarios A (fatal accident risk of cyclist in Copenhagen) and B (fatal accident risk of pedestrians in Paris); “European RR function for PM2.5”: Using a relative risk function of PM2.5 and all cause mortality reported in ESCAPE project (Beelen R, et al, 2014); “Fivefold toxicity of PM2.5”: Assuming a fivefold toxicity of PM2.5 from the traffic sources.</p
Baseline data and key assumptions used in the model.
No full textBaseline data and key assumptions used in the model.</p
Number of deaths and Number of deaths adjusted by 100,000 travellers who shifted modes per year, by heath exposure.
No full textScenarios. A: 35% of all trips by bicycle; B: 50% of all trips walking.</p
Evaluating different recruitment methods in a longitudinal survey: Findings from the pan-European PASTA project (Preprint)
No full textSufficient sample size and minimal sample bias are core requirements in
empirical data analyses. Combining opportunistic recruitment with an online survey and data
collection platform yields new benefits compared to traditional recruitment approaches.
Objective: The objective of this paper is to report on the success of different recruitment
methods to obtain participants’ characteristics, participation behavior, recruitment rates, and
representativeness of the sample.
Methods: A longitudinal online survey was implemented as part of the European PASTA
project, which was online between November 2014 and December 2016. During this period
participants in seven European cities were recruited on a rolling basis. For all cities to reach a
sufficient number of adult participants a standardized guide on recruitment strategy was
developed. In order to make use of the strengths and to minimize weakness a combination of
different opportunistic recruitment methods was applied. In addition, the city of Oerebro
applied random sampling approach. In order to reduce attrition rate and improve real-time
monitoring the online platform featured a participant and a researchers` user interface and
dashboard.
Results: A total of 10,691 participants were recruited. Most people found out about the
survey through their workplace or employer (21.5 %), outreach promotion (20.8 %), and
social media (17.4 %). The average number of questionnaires filled-in per participant varied
between the cities, with the highest number in Zurich (11.0 ± 0.33) and the lowest in
Oerebro (4.8 ± 0.17). Collaboration with local organizations, the use of Facebook and mailing
lists, and direct street recruitment were the most effective approaches in reaching a high
share of participants (p = <.001). Under consideration of invested working hours Facebook (p
= <.001) was one of the most time-efficient methods. Compared to the cities census data,
the composition of study participants was broadly representative in terms of gender
distribution, however included younger and better educated participants.
Conclusions: We observed that offering a mixed recruitment approach was very effective in
achieving a high participation rate. The highest attrition rate and the lowest average number
of questionnaires filled-in per participant were observed in Oerebro, who also recruited
participants through random sampling. The findings suggest that people that are more
interested in the topic are more willing to participate and to stay in a survey than those who
are selected randomly and may not have a strong connection to the research topic. Whereas
direct face-to-face contacts were very effective with respect to the number of recruited
participants; recruiting people through social media was not only effective, but also very
time-efficient. The collected data is based on one of the largest recruited longitudinal
samples with a common recruitment strategy in different European cities
Additional file 2: of Physical Activity through Sustainable Transport Approaches (PASTA): protocol for a multi-centre, longitudinal study
No full textThe full questionnaire of the PASTA longitudinal survey is provided as supplemental material, and is also available from http://pastaproject.eu/fileadmin/editor-upload/sitecontent/City_survey/PASTA-questionnaires.pdf . (PDF 3792 kb
