| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Abbafati, Cristiana, et al.
(författare)
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- 2020
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Ho, Hung Chak, et al.
(författare)
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“Planned greenspace” or “natural greenspace” in a high-density city with compact environment? An empirical study of osteoporosis among senior population
- 2022
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 219
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Tidskriftsartikel (refereegranskat)abstract
- Osteoporosis is a major physical health issue in healthy ageing among urban populations. However, few studies have investigated how greenspace can influence osteoporosis, especially to those who lived in a compact city with high-density living environment. Furthermore, no studies have investigated how “planned greenspace” and “natural greenspace” can separately influence osteoporosis among senior population. We hereby conducted an empirical study to evaluate the relationship between osteoporosis, “planned greenspace” and “natural greenspace”, based on the use of land use data derived from local geospatial information and satellite images. Our results showed that seniors who were 1) aged, 2) female, 3) less educated, 4) smokers, and 5) with chronic respiratory diseases were associated with osteoporosis. Considering factors of greenspace, a higher percentage of planned greenspace surrounding the residence may be a protective factor while natural greenspace did not influence the individuals. Specifically, a 10% increase of planned greenspace within the 600-m radius area surrounding the residence was negative associated with osteoporosis (−2.8% [-5.1%, −0.5%]). Based on our results, development of planned greenspace may be necessary, as compact built environment of a high-density city often resulted in a lack of planned greenspace for physical activities. Along with the World Health Organization (WHO) guidelines for an age-friendly city, our findings suggest that improving the planned greenspace in a walkable distance around one's neighboring environment is a potential strategy for prevention of osteoporosis and related physical health issues as well as for life quality improvement among the senior population.
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| 4. |
- Ho, Hung Chak, et al.
(författare)
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Systematic identification of heat events associated with emergency admissions to enhance the heat-health action plan in a subtropical city: a data-driven approach
- 2022
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Ingår i: Environmental Science and Pollution Research. - : Springer Nature. - 0944-1344 .- 1614-7499. ; 29:59, s. 89273-89282
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Tidskriftsartikel (refereegranskat)abstract
- According to the United Nations Office for Disaster Risk Reduction (UNDRR), a heat-health action plan should address various impacts of hazards at different levels, including an early warning system to monitor risks and behaviour enhancement to increase disaster preparedness. It is necessary to comply with guidelines regarding heat duration/intensity. In this study, we developed a data-driven approach to rapidly and systematically estimate the impacts of various heat events on emergency admissions among the adult population (n = 7,086,966) in Hong Kong in order to enhance the heat-health action plan. Immediate, short-term, and long-term impacts determined by 1-day, 4-day, and 8-day windows were estimated to identify specific heat events suitable for early warnings. In addition, underestimated risk, determined by a continuous increase in heat risk after days without significant emergency admissions, was estimated to evaluate potential maladaptive behaviours among a specific subpopulation. Based on age- and gender-specific analyses, 1D, 1D1N, and 2D2N were observed to have a stronger immediate impact on emergency admissions. 1D1N and 2D2N also showed notable short-term and long-term impacts. Based on heat vulnerability factors (age and gender), 2D2N was a higher-priority extreme heat event for early warning measures than 1D1N. Furthermore, men aged 19 to 64 had the highest underestimated risk. Specifically, they had IRR values of 1.113 [1.087, 1.140], 1.061 [1.035, 1.087], and 1.069 [1.043, 1.095] during lag days 3-5 of 3D2N, respectively, possibly due to a lack of adaptive behaviour. By adopting our approach, the duration of heat events with significant health impacts can be identified in order to further enhance relevant heat stress information. This framework can be applied to other cities with a similar background for rapid assessment.
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| 5. |
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| 6. |
- Zhao, Shuangming, et al.
(författare)
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How do taxi drivers expose to fine particulate matter (PM2.5) in a Chinese megacity : a rapid assessment incorporating with satellite-derived information and urban mobility data
- 2024
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Ingår i: International Journal of Health Geographics. - 1476-072X. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Taxi drivers in a Chinese megacity are frequently exposed to traffic-related particulate matter (PM2.5) due to their job nature, busy road traffic, and urban density. A robust method to quantify dynamic population exposure to PM2.5 among taxi drivers is important for occupational risk prevention, however, it is limited by data availability. Methods: This study proposed a rapid assessment of dynamic exposure to PM2.5 among drivers based on satellite-derived information, air quality data from monitoring stations, and GPS-based taxi trajectory data. An empirical study was conducted in Wuhan, China, to examine spatial and temporal variability of dynamic exposure and compare whether drivers’ exposure exceeded the World Health Organization (WHO) and China air quality guideline thresholds. Kernel density estimation was conducted to further explore the relationship between dynamic exposure and taxi drivers’ activities. Results: The taxi drivers’ weekday and weekend 24-h PM2.5 exposure was 83.60 μg/m3 and 55.62 μg/m3 respectively, 3.4 and 2.2 times than the WHO’s recommended level of 25 µg/m3. Specifically, drivers with high PM2.5 exposure had a higher average trip distance and smaller activity areas. Although major transportation interchanges/terminals were the common activity hotspots for both taxi drivers with high and low exposure, activity hotspots of drivers with high exposure were mainly located in busy riverside commercial areas within historic and central districts bounded by the “Inner Ring Road”, while hotspots of drivers with low exposure were new commercial areas in the extended urbanized area bounded by the “Third Ring Road”. Conclusion: These findings emphasized the need for air quality management and community planning to mitigate the potential health risks of taxi drivers.
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