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Siebert FW, Riis C, Janstrup KH, Lin H, Hüttel FB. Computer vision-based helmet use registration for e-scooter riders - The impact of the mandatory helmet law in Copenhagen. J Safety Res 2023; 87:257-265. [PMID: 38081699 DOI: 10.1016/j.jsr.2023.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 08/13/2023] [Accepted: 09/21/2023] [Indexed: 12/18/2023]
Abstract
PROBLEM E-scooters are a new form of mobility used more frequently in urban environments worldwide. As there is evidence of an increased risk of head injuries, helmets are recommended and (less frequently) legislated. Denmark has enacted mandatory e-scooter helmet use legislation from January 1, 2022. So far, it is unclear how this newly implemented law influenced helmet use of e-scooter riders in Denmark immediately after its implementation. METHOD In this observational study, we register and compare e-scooter helmet use before the mandatory helmet use legislation (December 2021) and after (February 2022). As observational survey data collection in the field can be highly time-consuming, we conducted a video-based observation survey. We trained and applied a computer vision algorithm to automatically register e-scooter helmet use in the video data. RESULTS The trained algorithm produces accurate helmet use data, which does not differ significantly from human-registered helmet use. In applying the algorithm to video data collected in December 2021 and February 2022, we register an overall e-scooter helmet use of 4.4% in n = 1054 riders. Splitting the observation between the time before and after the implementation of the helmet use law reveals a significant increase in helmet use from 1.80% to 5.56%. DISCUSSION In this study, we successfully train and apply an object detection algorithm to register accurate helmet use data in videos collected in Copenhagen, Denmark. Using this algorithm, we find a significant impact of a new mandatory e-scooter helmet use law on e-scooter riders' helmet use behavior. Limitations of the study as well as future research needs, are discussed. PRACTICAL APPLICATIONS Computer vision algorithms can be used for accurate e-scooter helmet assessments. Implementing a mandatory helmet use law can increase helmet use of e-scooters at specific observation sites.
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Affiliation(s)
- Felix Wilhelm Siebert
- DTU Management, Technical University of Denmark, Bygningstorvet 116, Kgs. Lyngby 2800, Denmark.
| | - Christoffer Riis
- DTU Management, Technical University of Denmark, Bygningstorvet 116, Kgs. Lyngby 2800, Denmark
| | - Kira Hyldekær Janstrup
- DTU Management, Technical University of Denmark, Bygningstorvet 116, Kgs. Lyngby 2800, Denmark
| | - Hanhe Lin
- School of Science and Engineering, University of Dundee, Nethergate, Dundee DD1 4HN, Scotland, United Kingdom
| | - Frederik Boe Hüttel
- DTU Management, Technical University of Denmark, Bygningstorvet 116, Kgs. Lyngby 2800, Denmark
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Lima AT, Hofmann A, Reynolds D, Ptacek CJ, Van Cappellen P, Ottosen LM, Pamukcu S, Alshawabekh A, O'Carroll DM, Riis C, Cox E, Gent DB, Landis R, Wang J, Chowdhury AIA, Secord EL, Sanchez-Hachair A. Environmental Electrokinetics for a sustainable subsurface. Chemosphere 2017; 181:122-133. [PMID: 28433930 DOI: 10.1016/j.chemosphere.2017.03.143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 06/07/2023]
Abstract
Soil and groundwater are key components in the sustainable management of the subsurface environment. Source contamination is one of its main threats and is commonly addressed using established remediation techniques such as in-situ chemical oxidation (ISCO), in-situ chemical reduction (ISCR; most notably using zero-valent iron [ZVI]), enhanced in-situ bioremediation (EISB), phytoremediation, soil-washing, pump-and-treat, soil vapour extraction (SVE), thermal treatment, and excavation and disposal. Decades of field applications have shown that these techniques can successfully treat or control contaminants in higher permeability subsurface materials such as sands, but achieve only limited success at sites where low permeability soils, such as silts and clays, prevail. Electrokinetics (EK), a soil remediation technique mostly recognized in in-situ treatment of low permeability soils, has, for the last decade, been combined with more conventional techniques and can significantly enhance the performance of several of these remediation technologies, including ISCO, ISCR, EISB and phytoremediation. Herein, we discuss the use of emerging EK techniques in tandem with conventional remediation techniques, to achieve improved remediation performance. Furthermore, we highlight new EK applications that may come to play a role in the sustainable treatment of the contaminated subsurface.
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Affiliation(s)
- A T Lima
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, Canada; Department of Environmental Engineering, Universidade Federal do Espírito Santo, Vitória, ES, Brazil.
| | - A Hofmann
- University of Lille, CNRS, UMR 8187, LOG, Laboratoire d'Océanologie et de Géosciences, 59655 Villeneuve d'Ascq, France
| | - D Reynolds
- Geosyntec Consultants, Waterloo, Ontario, Canada
| | - C J Ptacek
- Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, Canada
| | - P Van Cappellen
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, Canada
| | - L M Ottosen
- Department of Civil Engineering, Technical University of Denmark, Lyngby, Denmark
| | - S Pamukcu
- Department of Civil and Environmental Engineering, Lehigh University, Bethlehem, PA, USA
| | - A Alshawabekh
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, USA
| | - D M O'Carroll
- Department of Civil and Environmental Engineering, University of Western Ontario, London, ON, Canada; School of Civil and Environmental Engineering, Connected Water Initiative, University of New South Wales, Manly Vale, NSW, 2093, Australia
| | - C Riis
- NIRAS, Sortemosevej 19, 3450 Alleroed, Denmark
| | - E Cox
- Geosyntec Consultants, Waterloo, Ontario, Canada
| | - D B Gent
- Environmental Laboratory, USACE Engineer Research and Development Center, Vicksburg, MS, USA
| | - R Landis
- RichLand Consulting, LLC, Wilmington, DE, USA
| | - J Wang
- Geosyntec Consultants, Waterloo, Ontario, Canada
| | - A I A Chowdhury
- Department of Civil and Environmental Engineering, University of Western Ontario, London, ON, Canada
| | - E L Secord
- Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, Waterloo, Canada
| | - A Sanchez-Hachair
- University of Lille, CNRS, UMR 8187, LOG, Laboratoire d'Océanologie et de Géosciences, 59655 Villeneuve d'Ascq, France
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Johansen P, Riis C, Hasenkam JM, Paulsen PK, Nygaard H. A new method for quantitative evaluation of perceived sounds from mechanical heart valve prostheses. Proc Inst Mech Eng H 2000; 214:121-8. [PMID: 10718056 DOI: 10.1243/0954411001535291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Closing clicks from mechanical heart valve prostheses are transmitted to the patient's inner ear mainly in two different ways: as acoustically transmitted sound waves, and as vibrations transmitted through bones and vessels. The purpose of this study was to develop a method for quantifying what patients perceive as sound from their mechanical heart valve prostheses via these two routes. In this study, 34 patients with implanted mechanical bileaflet aortic and mitral valves (St Jude Medical and On-X) were included. Measurements were performed in a specially designed sound insulated chamber equipped with microphones, accelerometers, preamplifiers and a loudspeaker. The closing sounds measured with an accelerometer on the patient's chest were delayed 400 ms, amplified and played back to the patient through the loudspeaker. The patient adjusted the feedback sound to the same level as the 'real-time' clicks he or she perceived directly from his or her valve. In this way the feedback sound energy includes both the air- and the bone-transmitted energies. Sound pressure levels (SPLs) were quantified both in dB(A) and in the loudness unit sone according to ISO 532B (the Zwicker method). The mean air-transmitted SPL measured close to the patient's ear was 23 +/- 4 dB(A). The mean air- and bone-transmitted sounds and vibrations were perceived by the patients as an SPL of 34 +/- 5 dB(A). There was no statistically significant difference in the perceived sound from the two investigated bileaflet valves, and no difference between aortic and mitral valves. The study showed that the presented feedback method is capable of quantifying the perceived sounds and vibrations from mechanical heart valves, if the patient's hearing is not too impaired. Patients with implanted mechanical heart valve prostheses seem to perceive the sound from their valve two to three times higher than nearby persons, because of the additional bone-transmitted vibrations.
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Affiliation(s)
- P Johansen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Skejby Sygehus, Denmark
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Nygaard H, Johansen P, Riis C, Hasenkam JM, Paulsen PK. Assessment of perceived mechanical heart valve sound level in patients. J Heart Valve Dis 1999; 8:655-61. [PMID: 10616244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
BACKGROUND AND AIM OF THE STUDY When mechanical heart valves close, they generate an impulse that is transmitted to the patient's inner ear by two routes: (i) As acoustically transmitted sound waves; and (ii) as vibrations transmitted through bones and vessels. The aim of this study was to quantitate what patients perceive as sound from their mechanical heart valve prostheses - including both air-transmitted sound waves and bone-transmitted vibrations. METHODS Thirty-four patients with implanted mechanical bileaflet aortic and mitral valves (St. Jude Medical and On-X) were included in the study. Measurements were performed in a specially designed sound-insulated chamber equipped with microphones, accelerometers, preamplifiers and a loud-speaker. The closing sounds measured by an accelerometer on the patient's chest were delayed 400 ms, amplified and played back to the patient through the loudspeaker. The patient adjusted the feedback sound to the same level as the 'real-time' clicks they perceived directly from their valve. In this way the feedback sound energy includes both the air- and bone-transmitted energies. Sound pressure levels (SPL) were quantitated in both dB(A) and in loudness units (sones) according to ISO 532B (Zwicker method). RESULTS The mean air-transmitted SPL measured close to the patient's ear was 23 +/- 4 dB(A). The total air-and bone-transmitted sounds and vibrations were perceived by the patients as a SPL of 34 +/- 5 dB(A). There was no statistically significant difference in perceived sound from the two bileaflet valves investigated, and no difference between aortic and mitral valves. CONCLUSIONS The study showed that the presented feedback method is capable of quantitating the perceived sounds and vibrations from mechanical heart valves, if the patient's hearing is not too impaired. Patients with implanted mechanical heart valve prostheses seem to perceive the sound from their valve two to four times higher than nearby persons, because of the additional bone-transmitted vibrations.
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Affiliation(s)
- H Nygaard
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Skejby Sygehus, Denmark
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Kleine P, Perthel M, Nygaard H, Hansen SB, Paulsen PK, Riis C, Laas J. Medtronic Hall versus St. Jude Medical mechanical aortic valve: downstream turbulences with respect to rotation in pigs. J Heart Valve Dis 1998; 7:548-55. [PMID: 9793855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
BACKGROUND AND AIMS OF THE STUDY Turbulences downstream of mechanical aortic valves are known to contribute to most valve-related complications such as thrombosis, embolization or damage to blood components. In vitro studies have demonstrated the impact of the orientation of prostheses on transvalvular energy loss. This study evaluates the influence of valve orientation on turbulences in the supravalvular aorta in pigs. METHODS A rotation device which could carry a Medtronic Hall (MH) or St. Jude Medical (SJM) aortic valve prosthesis (23 mm) was constructed and implanted into four healthy pigs. Turbulence measurements using pulsed Doppler ultrasonography were carried out 3 cm downstream of the valve, while the prostheses were rotated in 45 degrees steps. Reynold's normal stress values (RNS) were calculated as key markers for turbulent stresses. RESULTS Turbulences downstream of MH and SJM valves demonstrated a significant change with rotation. The MH valve showed minimum RNSmean values with orientation of the large orifice to the right posterior aortic wall, which is the area of highest velocities during ejection. With this orientation, aortic flow almost complied with physiologic conditions. Increase of turbulence was observed with any other position. The SJM valve revealed significant turbulent flow at any orientation. Minimum RNSmean values were also measured with one orifice facing the right posterior wall of the aorta. CONCLUSION With optimum orientation (major orifice facing the right posterior aortic wall) the MH valve matches the aortic flow pattern to near-normal physiology. The flow patterns of the SJM valve are less susceptible to rotation, but cannot attain the optimum RNS values of the MH prosthesis.
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Affiliation(s)
- P Kleine
- Department of Thoracic and Cardiovascular Surgery, Herz-Kreislauf-Klinik Bevensen, Bad Bevensen, Germany
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Hasenkam JM, Nygaard H, Terp K, Riis C, Paulsen PK. Hemodynamic evaluation of a new bileaflet valve prosthesis: an acute animal experimental study. J Heart Valve Dis 1996; 5:574-80. [PMID: 8953434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND AIMS OF THE STUDY A newly developed heart valve (Medtronic Parallel) was tested in an acute animal experimental model. METHODS Five prototype valves were implanted in the aortic position in seven 90 kg pigs to enable acute evaluation of the hemodynamic performance in terms of turbulent stresses and transvalvular pressure drop. Turbulent stresses in the ascending aorta were measured using a 10 MHz perivascular Doppler echocardiographic transducer designed to measure the radical velocity component at 17 different points covering the aortic cross-sectional area. RESULTS The drop in transvalvular peak pressure measured with fluid-filled catheters showed a non-linear relationship with cardiac output and was always < 12 mmHg. The Reynolds normal stresses were < 60 N/m2 in systole within 50 ms time windows, which is insufficient to cause mechanical damage of the formed elements of the blood. CONCLUSIONS From a hemodynamic point of view the performance of the Medtronic Parallel aortic valve is fully acceptable and within the range of other similar, currently available mechanical valves.
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Affiliation(s)
- J M Hasenkam
- Department of Cardiothoracic and Vascular Surgery, Skejby Sygehus, Aarhus University Hospital, Denmark
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