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- 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. |
- Chen, Liangkai, et al.
(författare)
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Physical frailty, adherence to ideal cardiovascular health and risk of cardiovascular disease : a prospective cohort study
- 2023
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Ingår i: Age and Ageing. - : Oxford University Press. - 0002-0729 .- 1468-2834. ; 52:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: longitudinal evidence concerning frailty phenotype and the risk of cardiovascular disease (CVD) remained insufficient, and whether CVD preventive strategies exert low CVD risk on frail adults is unclear.Objectives: we aimed to prospectively evaluate the association of frailty phenotype, adherence to ideal cardiovascular health (CVH) and their joint associations with the risk of CVD.Methods: a total of 314,093 participants from the UK Biobank were included. Frailty phenotype was assessed according to the five criteria of Fried et al.: weight loss, exhaustion, low physical activity, slow gait speed and low grip strength. CVH included four core health behaviours (smoking, physical activity and diet) and three health factors (weight, cholesterol, blood pressure and glycaemic control). The outcome of interest was incident CVD, including coronary heart disease, heart failure and stroke.Results: compared with the non-frail people whose incident rate of overall CVD was 6.54 per 1,000 person-years, the absolute rate difference per 1,000 person-years was 1.67 (95% confidence interval, CI: 1.33, 2.02) for pre-frail and 5.00 (95% CI: 4.03, 5.97) for frail. The ideal CVH was significantly associated with a lower risk of all CVD outcomes. For the joint association of frailty and CVH level with incident CVD, the highest risk was observed among frailty accompanied by poor CVH with an HR of 2.92 (95% CI: 2.68, 3.18).Conclusions: our findings indicate that physical frailty is associated with CVD incidence. Improving CVH was significantly associated with a considerable decrease in CVD risk, and such cardiovascular benefits remain for the frailty population.
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