| 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. |
- Lakens, Daniel, et al.
(författare)
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Justify your alpha
- 2018
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Ingår i: Nature Human Behaviour. - : Nature Publishing Group. - 2397-3374. ; 2:3, s. 168-171
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Tidskriftsartikel (refereegranskat)abstract
- In response to recommendations to redefine statistical significance to P ≤ 0.005, we propose that researchers should transparently report and justify all choices they make when designing a study, including the alpha level.
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| 3. |
- Morais, Caio C. A., et al.
(författare)
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High Positive End-Expiratory Pressure Renders Spontaneous Effort Noninjurious
- 2018
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Ingår i: American Journal of Respiratory and Critical Care Medicine. - : AMER THORACIC SOC. - 1073-449X .- 1535-4970. ; 197:10, s. 1285-1296
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: In acute respiratory distress syndrome (ARDS), atelectatic solid-like lung tissue impairs transmission of negative swings in pleural pressure (Ppl) that result from diaphragmatic contraction. The localization of more negative Ppl proportionally increases dependent lung stretch by drawing gas either from other lung regions (e.g., nondependent lung [pendelluft]) or from the ventilator. Lowering the level of spontaneous effort and/or converting solid-like to fluid-like lung might render spontaneous effort noninjurious.Objectives: To determine whether spontaneous effort increases dependent lung injury, and whether such injury would be reduced by recruiting atelectatic solid-like lung with positive end-expiratory pressure (PEEP).Methods: Established models of severe ARDS (rabbit, pig) were used. Regional histology (rabbit), inflammation (positron emission tomography; pig), regional inspiratory Ppl (intrabronchial balloon manometry), and stretch (electrical impedance tomography; pig) were measured. Respiratory drive was evaluated in 11 patients with ARDS.Measurements and Main Results: Although injury during muscle paralysis was predominantly in nondependent and middle lung regions at low (vs. high) PEEP, strong inspiratory effort increased injury (indicated by positron emission tomography and histology) in dependent lung. Stronger effort (vs. muscle paralysis) caused local overstretch and greater tidal recruitment in dependent lung, where more negative Ppl was localized and greater stretch was generated. In contrast, high PEEP minimized lung injury by more uniformly distributing negative Ppl, and lowering the magnitude of spontaneous effort (i.e., deflection in esophageal pressure observed in rabbits, pigs, and patients).Conclusions: Strong effort increased dependent lung injury, where higher local lung stress and stretch was generated; effort-dependent lung injury was minimized by high PEEP in severe ARDS, which may offset need for paralysis.
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| 4. |
- Santos, Reginaldo, et al.
(författare)
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Binder Identification Using Pattern Recognition on Phantom Measurements
- 2016
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456. ; 65:3, s. 522-534
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes an automatic method for the identification of twisted pairs (TPs) sharing the same binder, based on the analysis of phantom circuit measurements. This type of circuit is often used for improving data transmission rates in communication systems, but in this paper, phantoming is used to reveal if a four-wire loop composed of two TPs is close enough and well balanced in order to be considered in the same binder. The method uses four features extracted from scattering parameter measures in phantom-mode between two TPs. These features are related to the presence of periodicities and impedance mismatch between the measurement device and the four-wire transmission line. The identification is done via application of two pattern recognition techniques, support vector machines and K-means, on scattering parameter obtained from the phantom-mode measurement of two TPs. This paper also describes a method to determine the length of the two TPs that share the same binder. Laboratory results confirm the accuracy of the proposed methods.
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