Robust estimation of bacterial cell count from optical density

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

Angiomyolipoma with epithelial cyst (AMLEC): A rare variant of fat poor angiomyolipoma mimicking malignant cystic mass on MR imaging

PubMed ID: 25921627Angiomyolipoma (AML) of the kidney is the most common benign neoplasm encountered indaily clinical practice. Typical AMLs comprise three elements: mature adipose tissue, bloodvessels, and smooth muscle. Since classic AMLs contain considerable amount of adiposetissue, they are easily recognized on computed tomography (CT) and magnetic resonanceimaging (MRI) [1]. On the other hand, some AMLs comprise too little fat to be detected withunenhanced CT. These lesions are called ''fat poor AMLs'' that may be misdiagnosed asrenal cell carcinoma (RCC) on cross sectional imaging [2,3]. Angiomyolipoma with epithelialcysts (AMLEC) is an extremely rare subtype of fat poor AML, which contains epithelial-linedcysts. According to best of our knowledge imaging findings of AMLEC is very scarce and onlya total of 18 cases have been reported so far [4-8]. Herein, we aimed to report the MRIfeatures of AMLEC that resembles Bosniak category III lesion on MRI and emphasize thepotential role of dual gradient-echo imaging in detecting small amount of fat in AMLEC. © 2015 Published by Elsevier Masson SAS on behalf of the Editions francaises de radiologie

Hybrid foetus with an FE head for a pregnant occupant model for vehicle safety investigations

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.‘Expecting’, a computational pregnant occupant model, developed to simulate the dynamic response to crash impacts, possesses anthropometric properties of a fifth percentile female at around the 38th week of pregnancy. The model is complete with a finite element uterus and a multi-body foetus which is a novel feature in models of this kind. In this paper, the effect of incorporating a foetus with a finite element head into ‘Expecting’ is investigated. The finite element head was developed using detailed anatomic geometry and projected material properties. Then it was integrated with the ‘Expecting’ model and validated using the lap belt loading and the rigid bar impact tests. The model is then used to simulate frontal impacts at a range of crash severities with seatbelt and airbag, seatbelt only, airbag only as well as no restraint cases to investigate the risk of placental abruption and compare it with the model featuring the original multi-body foetus. The maximum strains developed in the utero-placental interface are used as the main criteria for foetus safety. The results show comparable strain levels to those from the multi-body foetus. It is, therefore, recommended to use the multi-body foetus in simulations as the computation time is more favourable