| 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. |
- Sheng, Renwang, et al.
(författare)
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Material stiffness in cooperation with macrophage paracrine signals determines the tenogenic differentiation of mesenchymal stem cells
- 2023
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Ingår i: Advanced Science. - : John Wiley & Sons. - 2198-3844. ; 10:17
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Tidskriftsartikel (refereegranskat)abstract
- Stiffness is an important physical property of biomaterials that determines stem cell fate. Guiding stem cell differentiation via stiffness modulation has been considered in tissue engineering. However, the mechanism by which material stiffness regulates stem cell differentiation into the tendon lineage remains controversial. Increasing evidence demonstrates that immune cells interact with implanted biomaterials and regulate stem cell behaviors via paracrine signaling; however, the role of this mechanism in tendon differentiation is not clear. In this study, polydimethylsiloxane (PDMS) substrates with different stiffnesses are developed, and the tenogenic differentiation of mesenchymal stem cells (MSCs) exposed to different stiffnesses and macrophage paracrine signals is investigated. The results reveal that lower stiffnesses facilitates tenogenic differentiation of MSCs, while macrophage paracrine signals at these stiffnesses suppress the differentiation. When exposed to these two stimuli, MSCs still exhibit enhanced tendon differentiation, which is further elucidated by global proteomic analysis. Following subcutaneous implantation in rats for 2 weeks, soft biomaterial induces only low inflammation and promotes tendon-like tissue formation. In conclusion, the study demonstrates that soft, rather than stiff, material has a greater potential to guide tenogenic differentiation of stem cells, which provides comprehensive evidence for optimized bioactive scaffold design in tendon tissue engineering.
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| 3. |
- Chen, Chi Kuang, et al.
(författare)
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From quality control to TQM, service quality and service sciences : a 30-year review of TQM literature
- 2022
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Ingår i: International Journal of Quality and Service Sciences. - : EMERALD GROUP PUBLISHING LTD. - 1756-669X .- 1756-6703. ; 14:2, s. 217-237
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Forskningsöversikt (refereegranskat)abstract
- Purpose: This paper aims to review total quality management (TQM) literature in the past three decades to identify the quality related key terms, to analyse their linkage among the identified key terms and their developmental trends. Design/methodology/approach: Bibliometric and statistical methods are used to analyse article titles published in the Total Quality and Business Excellence journal during 1990–2019. The current research is based on a search from the ProQuest academic database and the journal’s website, resulting in 2,452 articles collected. The VOSviewer and Microsoft Excel were then used for the analyses. Findings: A total of 52 key terms were extracted from the journal’s 2,452 article titles, the top three key terms in terms of occurrences were “quality,” “total quality management” and “service quality.” Five themes were then proposed from clustering the 52 key terms: “frameworks/models,” “essentials/enablers,” “methods/techniques,” “culture/characteristics” and “effects/results.” Trend analyses were also conducted regarding the five themes in an attempt to highlight the patterns of research publications from 1990 to 2019. It is found that the research publications for “essentials/enablers,” “methods and techniques” and “effects/results” have steadily increased during the analysis period, while “frameworks/models” and “culture/characteristic” have slightly decreased. These insights provide implication for the historical evolution of quality from “quality control,” “total quality management” and “service quality,” combining with the development of “service sciences.” Originality/value: This paper highlights the concept of quality since its meaning has changed and evolved over time from quality control, TQM to service quality. And it is emerging in the present and future development of service sciences because of both of TQM and service sciences having the same nature of multidisciplinary background and characteristics. Also the authors can conclude that quality and service sciences are in fact two sides of the same coin because both of them having the same duality of “tangible-intangible” and “physical-virtual” faces which are the important topics that TQM should focus on.
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