Viscous hydrophilic injection matrices for serial crystallography

Serial (femtosecond) crystallography at synchrotron and X-ray free-electron laser (XFEL) sources distributes the absorbed radiation dose over all crystals used for data collection and therefore allows measurement of radiation damage prone systems, including the use of microcrystals for room-temperature measurements. Serial crystallography relies on fast and efficient exchange of crystals upon X-ray exposure, which can be achieved using a variety of methods, including various injection techniques. The latter vary significantly in their flow rates – gas dynamic virtual nozzle based injectors provide very thin fast-flowing jets, whereas high-viscosity extrusion injectors produce much thicker streams with flow rates two to three orders of magnitude lower. High-viscosity extrusion results in much lower sample consumption, as its sample delivery speed is commensurate both with typical XFEL repetition rates and with data acquisition rates at synchrotron sources. An obvious viscous injection medium is lipidic cubic phase (LCP) as it is used for in meso membrane protein crystallization. However, LCP has limited compatibility with many crystallization conditions. While a few other viscous media have been described in the literature, there is an ongoing need to identify additional injection media for crystal embedding. Critical attributes are reliable injection properties and a broad chemical compatibility to accommodate samples as heterogeneous and sensitive as protein crystals. Here, the use of two novel hydro­gels as viscous injection matrices is described, namely sodium carb­oxy­methyl cellulose and the thermo-reversible block polymer Pluronic F-127. Both are compatible with various crystallization conditions and yield acceptable X-ray background. The stability and velocity of the extruded stream were also analysed and the dependence of the stream velocity on the flow rate was measured. In contrast with previously characterized injection media, both new matrices afford very stable adjustable streams suitable for time-resolved measurements

Multi-laboratory efforts for the standardization of performance assessment of diffuse optics instruments - The BitMap Exercise

A multi-laboratory exercise, involving 29 diffuse optical instruments, aimed at performance assessment of diffuse optics instruments on standardized protocols is presented. The overarching methodology and future actions will also be discussed

A multi-laboratory comparison of photon migration instruments and their performances – the BitMap Exercise

Performance assessment and standardization are indispensable for instruments of clinical relevance in general and clinical instrumentation based on photon migration/diffuse optics in particular. In this direction, a multi-laboratory exercise was initiated with the aim of assessing and comparing their performances. 29 diffuse optical instruments belonging to 11 partner institutions of a European level Marie Curie Consortium BitMap1 were considered for this exercise. The enrolled instruments covered different approaches (continuous wave, CW; frequency domain, FD; time domain, TD and spatial frequency domain imaging, SFDI) and applications (e.g. mammography, oximetry, functional imaging, tissue spectroscopy). 10 different tests from 3 well-accepted protocols, namely, the MEDPHOT2, the BIP3, and the nEUROPt4 protocols were chosen for the exercise and the necessary phantoms kits were circulated across labs and institutions enrolled in the study. A brief outline of the methodology of the exercise is presented here. Mainly, the design of some of the synthetic descriptors, (single numeric values used to summarize the result of a test and facilitate comparison between instruments) for some of the tests will be discussed.. Future actions of the exercise aim at deploying these measurements onto an open data repository and investigating common analysis tools for the whole dataset

How science informs engineering, education, and enforcement: A message for driving instructors

The aim of this chapter is to illustrate to driving instructors how science contributes to cumulative knowledge on road safety. We do this by reviewing a scientific study for each of the three classical Es of road safety: (1) education, (2) enforcement, and (3) engineering.Regarding education, we review the DeKalb experiment from the 1980s, which was a largesample randomized controlled trial that studied the effect of driver education on postlicense crash rates. The DeKalb experiment showed that participants who were assigned to a state-of-the-art driver education program performed better on theory and road tests, and became licensed sooner than control participants who did not receive formal driving instruction. Although the state-of-the-art education improved these target outcomes, there is no consistent evidence that it reduced crash risk. The recent consensus is that theoretical knowledge and skillful maneuvering alone are not sufficient for safe driving. Drivers should also have postlicense on-road experience and the lifestyle and attitudes that contribute to a safe driving style.Regarding enforcement, we describe a UK study from the late 1990s on the statistical reliability of the formal road test. In this study, driving test candidates were asked to retake the test with a different examiner. The results showed surprisingly low consistency between the two tests, indicating that an assessment of a 30-minute drive might not be trustworthy. We provide several recommendations (such as increasing the test duration and implementing standardized routes and checklists) for improving the reliability of road testing. Furthermore, the value of computerized testing (e.g., hazard perception testing) and long-term data collection (e.g., in-vehicle driver state monitoring) is addressed.Regarding engineering, the growing prevalence of active safety systems in vehicles has raised the question of how to treat such technologies in driver education curricula. A study on electronic stability control (ESC) was reviewed to illustrate how advances in technology improve road safety and affect elements of on-road training. In the case of ESC, skid training has become less relevant, but it is unknown whether learner drivers should experience critical driving situations during which the ESC gets activated. This may foster their overconfidence

A literature review on human factors research using motorcycle simulators

Biomechanical EngineeringMechanical, Maritime and Materials Engineerin

A literature review on human factors research using motorcycle simulators (poster)

Biomechanical EngineeringMechanical, Maritime and Materials Engineerin

Riding performance on a conventional bicycle and a pedelec in low speed exercises: Objective and subjective evaluation of middle-aged and older persons

This study investigated cycling performance of middle-aged (30–45 years old; n = 30) versus older (65+ years; n = 31) participants during low-speed tasks for which stabilization skills are known to be important. Additionally, participants’ self-ratings of their cycling skills and performance were assessed. Participants rode once on a conventional bicycle and once on a pedelec, in counterbalanced order. Three standardized tasks were performed: (1) low-speed cycling, (2) acceleration from a standstill, and (3) shoulder check. During Tasks 1 and 3, the mean absolute steering angle (a measure of the cyclist's steering activity) and the mean absolute roll rate (a measure of the amount of angular movement of the frame) were significantly greater for older participants than for middle-aged participants. These large lateral motions among older cyclists may indicate a difficulty to control the inherently unstable system. Comparing the conventional bicycle and the pedelec, participants reached a 16 km/h threshold speed in Task 2 sooner on the pedelec, an effect that was most pronounced among the older participants. Correlations between skills assessed with the Cycling Skill Inventory and actual measures of cycling performance were mostly not statistically significant. This indicates that self-reported motor-tactical and safety skills are not strongly predictive of measures of actual cycling performance. Our findings add to the existing knowledge on self-assessment of cycling skills, and suggest that age-related changes in psychomotor and sensory functions pose hazards for cycling safety.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent Vehicles & Cognitive RoboticsBiomechatronics & Human-Machine ControlTransport and Plannin