| 1. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)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. |
- Lynch, Christopher D, et al.
(author)
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Attitudes of some European dental undergraduate students to the placement of direct restorative materials in posterior teeth
- 2010
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In: Journal of Oral Rehabilitation. - : Blackwell Publishing Ltd. - 1365-2842 .- 0305-182X. ; 37:12, s. 916-926
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Journal article (peer-reviewed)abstract
- Summary The aim of this article was to report on the attitudes, opinions and confidences of final year dental students in three European schools towards the restoration of posterior teeth and in particular towards the use of amalgam and resin composite. One hundred and twenty-eight pre-piloted questionnaires were distributed to final year dental students in Cardiff, Dublin and Malmö. The questionnaire sought information relating to various opinions and attitudes towards the use of amalgam and resin composite in posterior teeth. Information was returned anonymously. Ninety-one completed questionnaires were returned (response rate = 71%; Cardiff: n = 40, Dublin: n = 24, Malmö: n = 27). Ninety-three per cent of Malmö students (n = 24), 67% of Dublin students (n = 16) and 60% of Cardiff students (n = 24) reported that they feel confident when placing posterior resin composites. One hundred per cent of Malmö students (n = 27), 75% of Cardiff students (n = 30) and 33% of Dublin students (n = 8) would prefer to have a resin composite rather than amalgam, placed in one of their own posterior teeth. Eighty-five per cent of Malmö students (n = 23), 30% of Cardiff students (n = 12) and 25% of Dublin students (n = 6) perceive amalgam as being harmful to the environment. For the restoration of a posterior tooth in a pregnant female, 44% of students (n = 40) would place a resin composite restoration, and 7% (n = 6) would place an amalgam restoration, while 32% (n = 29) would place a temporary restoration. Students at Malmö report that they place more posterior resin composites and have greater confidence at placing posterior resin composites than students at Cardiff or Dublin. There was confusion relating to the choice of restorative materials for pregnant females. Large variations in restorative strategies among graduates must be considered as dental professionals can practice in all countries within the European Union.
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