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- 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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- Janaudis-Ferreira, Tania, et al.
(author)
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Relationship and responsiveness of three upper-limb tests in patients with chronic obstructive pulmonary disease
- 2013
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In: Physiotherapy Canada. - : University of Toronto Press Inc. (UTPress). - 0300-0508 .- 1708-8313. ; 65:1, s. 40-43
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Journal article (peer-reviewed)abstract
- Purpose: To determine (1) the relationship among three common upper-limb tests for patients with chronic obstructive pulmonary disease (COPD): unsupported upper limb exercise test (UULEX), 6-minute pegboard and ring test (6PBRT), and a muscle-strength test using a hand-held dynamometer; and (2) the responsiveness of these three tests to changes after pulmonary rehabilitation that included a resistance arm-training programme.Methods: The study was a secondary analysis of a randomized controlled trial (RCT). The UULEX and the 6PBRT were used to measure peak arm exercise capacity and arm function, respectively. A handheld dynamometer was used to measure elbow and shoulder flexion force. We analyzed baseline data for all participants in the ACT, as well as baseline and post-PR data for those who completed 6-week follow-up testing.Results: 36 patients with COPD (mean forced expiratory volume in 1 second [FEV1] = 35% [SD 15%] predicted; age 66 [9] y) participated, of whom 13 completed an arm-training programme. The correlations among the test results ranged from 0.41 to 0.81 (p < 0.0001). Standardized response means were 1.0 for muscle force of elbow flexion, 1.2 for shoulder flexion, and 1.8 for the 6PBRT and UULEX.Conclusions: Although the three tests (UULEX, 6PBRT, and muscle-strength test using a hand-held dynamometer) are intended to measure different constructs, they were moderately to highly correlated with one another. The 6PBRT, UULEX, and muscle-strength test were demonstrated to be responsive to the resistance arm-training programme.
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- Janaudis-Ferreira, Tania, 1976-, et al.
(author)
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Resistance arm training in patients with chronic obstructive pulmonary disease : a randomized controlled trial
- 2011
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In: Chest. - : American College of Chest Physicians. - 0012-3692 .- 1931-3543. ; 139:1, s. 151-158
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Journal article (peer-reviewed)abstract
- BACKGROUND: The study aimed to evaluate the effect of upper extremity resistance training for patients with COPD on dyspnea during activity of daily living (ADL), arm function, arm exercise capacity, muscle strength and health related quality of life (HRQL)METHODS: Patients were randomly assigned to an intervention or control group. The intervention group underwent arm resistance training. The control group performed a sham. Both groups exercised 3 times a week for 6 weeks. Dyspnea during ADL and HRQL were measured using the chronic respiratory disease questionnaire (CRDQ). Arm function and exercise capacity were measured using the 6-minute pegboard and ring test (6PBRT) and the unsupported upper limb exercise test (UULEX), respectively. Muscle strength for the biceps, triceps, anterior and middle deltoids was obtained using an isometric dynamometer.RESULTS: Thirty-six patients with COPD (66 +/- 9 yrs) participated in the study. Compared with the control group, the magnitude of change in the intervention group was greater for the 6PBRT (p = 0.03), UULEX (p = 0.01) and elbow flexion force (p = 0.01); elbow extension force (p = 0.02), shoulder flexion force (p = 0.029) and shoulder abduction force (p = 0.01). There was no between-group difference in dyspnea during ADL, HRQL or symptoms during the 6PBRT or UULEX (all p values greater than 0.08).CONCLUSIONS: Resistance based arm training improved arm function, arm exercise capacity and muscle strength in patients with COPD. No improvement in dyspnea during ADL, HRQL or symptoms was demonstrated.
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