167 research outputs found

    Gender differences in cyclists\u2019 crashes: an analysis of routinely recorded crash data

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    Previous research on gender differences in road crashes has focussed uniquely on car drivers and there has been little research examining such differences among cyclists. In this study, we investigated gender differences in bicycle crashes, using routinely recorded crash data. The present paper focussed on characteristics related to the type of crashes (type of collision and opponent vehicle), the infrastructure (road type and type of road segment), the environmental (season, road surface condition and weather) and time period (time of the day and day of the week). Results revealed that, compared to women cyclists, men cyclists were more likely to be involved in a crash regardless the cyclists\u2019 age. Moreover, we found gender differences in terms of type of road segment, type of opponent vehicle, type of manoeuvre of the opponent vehicle and of the cyclists, type of collision, time of the day, day of the week and season

    Commentary: Principles, Approaches and Challenges of Applying Big Data in Safety Psychology Research

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    This commentary builds upon the recent theoretical paper by Kang et al. (2019) to advance the debate currently going on about psychology and big data. The aim is to discuss the feasibility of extending the conceptualization proposed by the authors\u2014i.e., Big Data of Safety Psychology (BDSP)\u2014to other branches of psychology going beyond the only safety domain, ultimately pointing out a big data of whatever psychology scenario. This will lead to suggest a perspective enrichment from a solely big data applied to psychology paradigm toward a much less advocated psychology applied to big data

    Ultra-Stable and Robust Response to X-Rays in 2D Layered Perovskite Micro-Crystalline Films Directly Deposited on Flexible Substrate

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    2D layered hybrid perovskites have recently attracted an increasing interest as active layers in LEDs and UV–Vis photodetectors. 2D perovskites crystallize in a natural self-assembled quantum well-like structure and possess several interesting features among which low-temperature (<100 °C) synthesis and low defect density. Here are presented solid-state ionizing radiation direct detectors based on the 2D layered hybrid perovskite PEA2PbBr4 (PEA = C6H5C2H4NH3+) deposited from solution using scalable techniques and directly integrated onto a pre-patterned flexible substrate in the form of micro-crystalline films displaying crystal-like behavior, as evidenced by the ultra-fast (sub-microsecond) and good detection performances under UV light. The effective detection of X-rays (up to 150 kVp) is demonstrated with sensitivity values up to 806 µC Gy−1 cm−2 and Limit of Detection of 42 nGy s−1, thus combining the excellent performance for two relevant figures of merit for solid-state detectors. Additionally, the tested devices exhibit exceptionally stable response under constant irradiation and bias, assessing the material robustness and the intimate electrical contact with the electrodes. PEA2PbBr4 micro-crystalline films directly grown on flexible pre-patterned substrate open the way for large-area solid-state detectors working at low radiation flux for ultra-fast X-ray imaging and dosimetry

    A Cluster Analysis of Cyclists in Europe: Common Patterns, Behaviours, and Attitudes

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    This study uses cluster analysis on a sample of regular cyclists from six European countries (the U.K., the Netherlands, Sweden, Hungary, Italy, and Spain) to shed light on common cycling patterns, demographic characteristics, and attitudes. Participants completed an online survey on cycling behaviour, attitudes towards cycling, discomfort while cycling in mixed traffic, cycling environment and comparative cycling risk perception. A two-step cluster analysis was performed to identify segments of cyclists based on cycling patterns, and a multinomial logistic regression analysis was used to profile the segments. The two-step cluster analysis yielded three components. Leisure-time cyclists cycled almost exclusively for leisure/training, had a clear preference for car use relative to bicycle, and low riding frequency. Resolute Cyclists were characterised by a high variety of cycling trip purpose, a clear preference for bicycle use relative to the car, and high riding frequency. Convenience Cyclists were characterised by cycling for personal business or leisure/training but not for commuting, no evident preference for bicycle vs car, and medium riding frequency. The value of the present study is to highlight commonalities in patterns, characteristics, and attitudes of cyclists in Europe. Our study showed that cycling patterns and habits are linked to psychosocial variables such as attitudes and the cycling environment, explicitly highlighting the importance of discomfort in mixed traffic and the relationship with cycling culture

    Organic Electrochemical Transistors as Versatile Analytical Potentiometric Sensors

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    Potentiometric transduction is an important tool of analytical chemistry to record chemical signals, but some constraints in the miniaturization and low-cost fabrication of the reference electrode are a bottleneck in the realization of more-advanced devices such as wearable and lab-on-a-chip sensors. Here, an organic electrochemical transistor (OECT) has been designed with an alternative architecture that allows to record the potentiometric signals of gate electrodes, which have been chemically modified to obtain Ag/AgnX interfaces (X = Cl−, Br−, I−, and S2−), without the use of a reference electrode. When the OECT is immersed in a sample solution, it reaches an equilibrium state, because PEDOT:PSS exchanges charges with the electrolyte until its Fermi level is aligned to the one of Ag/AgnX. The latter is controlled by Xn− concentration in the solution. As a consequence, in this spontaneous process, the conductivity of PEDOT:PSS changes with the electrochemical potential of the modified gate electrode without any external bias. The sensor works by applying only a fixed drain current or drain voltage and thus the OECT sensor operates with just two terminals. It is also demonstrated that, in this configuration, gate potential values extracted from the drain current are in good agreement with the ones measured with respect to a reference electrode being perfectly correlated (linear slope equal to 1.00 ± 0.03). In the case of the sulfide anion, the OECT performance overcomes the limit represented by the Nernst equation, with a sensitivity of 0.52 V decade−1. The presented results suggest that OECTs could be a viable option to fabricate advanced sensors based on potentiometric transduction

    Textile chemical sensors based on conductive polymers for the analysis of sweat

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    Wearable textile chemical sensors are promising devices due to the potential applications in medicine, sports activities and occupational safety and health. Reaching the maturity required for commercialization is a technology challenge that mainly involves material science because these sensors should be adapted to flexible and light-weight substrates to preserve the comfort of the wearer. Conductive polymers (CPs) are a fascinating solution to meet this demand, as they exhibit the mechanical properties of polymers, with an electrical conductivity typical of semiconductors. Moreover, their biocompatibility makes them promising candidates for effectively interfacing the human body. In particular, sweat analysis is very attractive to wearable technologies as perspiration is a naturally occurring process and sweat can be sampled non-invasively and continuously over time. This review discusses the role of CPs in the development of textile electrochemical sensors specifically designed for real-time sweat monitoring and the main challenges related to this topic

    Selective detection of liposoluble vitamins using an organic electrochemical transistor

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    Accurate quantification of vitamins content is essential in food analysis, with direct impact on the quality of our diet and, therefore, on our health. Current research interest is devoted to the design of robust and versatile devices able to perform real-time analyses that do not strictly rely on laboratory facilities. Here, we report the first organic electrochemical transistor (OECT) based sensor working in organic environment for the detection of a fat-soluble vitamin (Vitamin A). The OECT behaviour in organic solvents was thoroughly characterized and its structure was optimised allowing both potentiostatic and potentiodynamic detections. On one hand, the potentiostatic approach provided a gain of 100 and the detection limit was as low as 115 nM, but it did not address selectivity issues. On the other hand, the potentiodynamic approach showed a higher detection limit, but allowed the selective detection of Vitamin A in the presence of & alpha;-Tocopherol. Analyses of randomized solutions revealed that a pre-calibrated sensor can estimate Vitamin A concentration with a 3% error. Moreover, the robustness of our sensor was demonstrated by analysing commercial food fortifiers without any sample pretreatment

    Gender differences in cycling patterns and attitudes towards cycling in a sample of European regular cyclists

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    Previous research has shown that men cycle more than women and women tent to report less favourable perceptions and attitudes towards cycling than men. Gender differences in perceptions and attitudes towards cycling may be influenced by such difference in bicycle use. Attitudinal differences concerning cycling between male and female may be the consequence and not only the cause of gender imbalance in bicycle use. To our knowledge, no previous research has focused on gender differences in perceptions and attitudes towards cycling involving a sample with gender balance in bicycle use (e.g. regular cyclists). In our study, we investigated gender differences in attitudes towards cycling and towards cycling infrastructure, purpose of cycling, risk perception, and exposure to severe crashes in a large sample of regular cyclists. Following a cross-sectional design, we collected data from 2417 participants from Hungary, Italy, Spain, Sweden, Netherlands, and United Kingdom. A survey was administered to an online panel of respondents. Gender differences in attitudes towards cycling were small in terms of effect size or non-significant, with women having more positive attitudes in personal benefits rather than mobility benefits. Women reported gender-stereotyped reasons for cycling more than men, except for social activities. Also, women showed higher discomfort than men cycling in mixed traffic and higher risk perception than men. Furthermore, men reported higher exposure to severe crashes than women. We contend that bicycle use and gender role (i.e. society's shared beliefs concerning a range of attitudes, norms, and behaviours that are generally considered appropriate or desirable for individuals based on their actual or perceived sex) can affect differences between male and female cyclists in perceptions, attitudes towards cycling, and cycling behaviours

    Two-dimensional electron gas formation in undoped In[0.75]Ga[0.25]As/In[0.75]Al[0.25]As quantum wells

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    We report on the achievement of a two-dimensional electron gas in completely undoped In[0.75]Al[0.25]As/In[0.75]Ga[0.25]As metamorphic quantum wells. Using these structures we were able to reduce the carrier density, with respect to reported values in similar modulation-doped structures. We found experimentally that the electronic charge in the quantum well is likely due to a deep-level donor state in the In[0.75]Al[0.25]As barrier band gap, whose energy lies within the In[0.75]Ga[0.25]As/In[0.75]Al[0.25]As conduction band discontinuity. This result is further confirmed through a Poisson-Schroedinger simulation of the two-dimensional electron gas structure.Comment: 17 pages, 6 figures, to be published in J. Vac. Sci. Technol.

    A wearable electrochemical gas sensor for ammonia detection

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    The next future strategies for improved occupational safety and health management could largely benefit from wearable and Internet of Things technologies, enabling the real-time monitoring of health-related and environmental information to the wearer, to emergency responders, and to inspectors. The aim of this study is the development of a wearable gas sensor for the detection of NH3 at room temperature based on the organic semiconductor poly(3,4-ethylenedioxythiophene) (PEDOT), electrochemically deposited iridium oxide particles, and a hydrogel film. The hydrogel composition was finely optimised to obtain self-healing properties, as well as the desired porosity, adhesion to the substrate, and stability in humidity variations. Its chemical structure and morphology were characterised by infrared spectroscopy and scanning electron microscopy, respectively, and were found to play a key role in the transduction process and in the achievement of a reversible and selective response. The sensing properties rely on a potentiometric-like mechanism that significantly differs from most of the state-of-the-art NH3 gas sensors and provides superior robustness to the final device. Thanks to the reliability of the analytical response, the simple two-terminal configuration and the low power consumption, the PEDOT:PSS/IrOx Ps/hydrogel sensor was realised on a flexible plastic foil and successfully tested in a wearable configuration with wireless connectivity to a smartphone. The wearable sensor showed stability to mechanical deformations and good analytical performances, with a sensitivity of 60 ± 8 µA decade−1 in a wide concentration range (17–7899 ppm), which includes the safety limits set by law for NH3 exposure
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