Development of an optical system for the non-invasive tracking of stem cell growth on microcarriers

The emergence of medicinal indications for stem cell therapies has seen a need to develop the manufacturing capacity for adherent cells such as mesenchymal stem cells (MSCs). One such development is in the use of microcarriers, which facilitate enhanced cell densities for adherent stem cell cultures when compared with 2D culture platforms. Given the variety of stem cell expansion systems commercially available, novel methods of non-invasive and automated monitoring of cell number, confluence, and aggregation, within disparate environments, will become imperative to process control, ensuring reliable and consistent performance. The in situ epi-illumination of mouse embryonic fibroblasts and human mesenchymal stem cells attached to Cytodex 1 and 3 microcarriers was achieved using a bespoke microscope. Robust image processing techniques were developed to provide quantitative measurements of confluence, aggregate recognition, and cell number, without the need for fluorescent labeling or cell detachment. Large datasets of cells counted on individual microcarriers were statistically analyzed and compared with NucleoCounter measurements, with an average difference of less than 7 observed from days 0 to 6 of a 12-day culture noted, prior to the onset of aggregation. The developed image acquisition system and post-processing methodologies were successfully applied to dynamically moving colonized microcarriers. The proposed system offers a novel method of cell identification at the individual level, to consistently and accurately assess viable cell number, confluence, and cell distribution, while also minimizing the variability inherent in the current invasive means by which cells adhered to microcarriers are analyzed. Biotechnol. Bioeng. 2017;9999: 1–11. © 2017 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc

A computational framework for particle and whole cell tracking applied to a real biological dataset

Cell tracking is becoming increasingly important in cell biology as it provides a valuable tool for analysing experimental data and hence furthering our understanding of dynamic cellular phenomena. The advent of high-throughput, high-resolution microscopy and imaging techniques means that a wealth of large data is routinely generated in many laboratories. Due to the sheer magnitude of the data involved manual tracking is often cumbersome and the development of computer algorithms for automated cell tracking is thus highly desirable. In this work, we describe two approaches for automated cell tracking. Firstly, we consider particle tracking. We propose a few segmentation techniques for the detection of cells migrating in a non-uniform background, centroids of the segmented cells are then calculated and linked from frame to frame via a nearest-neighbour approach. Secondly, we consider the problem of whole cell tracking in which one wishes to reconstruct in time whole cell morphologies. Our approach is based on fitting a mathematical model to the experimental imaging data with the goal being that the physics encoded in the model is reflected in the reconstructed data. The resulting mathematical problem involves the optimal control of a phase-field formulation of a geometric evolution law. Efficient approximation of this challenging optimal control problem is achieved via advanced numerical methods for the solution of semilinear parabolic partial differential equations (PDEs) coupled with parallelisation and adaptive resolution techniques. Along with a detailed description of our algorithms, a number of simulation results are reported on. We focus on illustrating the effectivity of our approaches by applying the algorithms to the tracking of migrating cells in a dataset which reflects many of the challenges typically encountered in microscopy data

An examination of the self-referent executive processing model of test anxiety: control, emotional regulation, self-handicapping, and examination performance

According to the self-referent executive processing (S-REF) model, test anxiety develops from interactions between three systems: executive self-regulation processes, self-beliefs, and maladaptive situational interactions. Studies have tended to examine one system at a time, often in conjunction with how test anxiety relates to achievement outcomes. The aim of this study was to enable a more thorough test of the S-REF model by examining one key construct from each of these systems simultaneously. These were control (a self-belief construct), emotional regulation through suppression and reappraisal (an executive process), and self-handicapping (a maladaptive situational interaction). Relations were examined from control, emotional regulation, and self-handicapping to cognitive test anxiety (worry), and subsequent examination performance on a high-stakes test. Data were collected from 273 participants in their final year of secondary education. A structural equation model showed that higher control was indirectly related to better examination performance through lower worry, higher reappraisal was indirectly related to worse examination performance through higher worry, and higher self-handicapping was related to worse examination performance through lower control and higher worry. These findings suggest that increasing control and reducing self-handicapping would be key foci for test anxiety interventions to incorporate. © 2018 The Author(s

A study of the rise and decline of selected Labour halls in the Greater London area 1918-1979

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

[[alternative]]The natural medications for wound healing - Curcumin, Aloe-Vera and Ginger - do not induce a significant effect on the migration kinematics of cultured fibroblasts

[[abstract]]Curcumin, Aloe-vera and Ginger are popular natural medications (NMs) for treating wounds, however, the mechanisms by which these NMs apparently accelerate wound healing remain largely unknown. From a biomechanical perspective, it is specifically unclear whether fibroblast motility improves in the presence of any of these NMs. Here we use our recently developed quantitative high-precision automated assay for cell migration (Topman et al., 2012b) which is based on image processing of time lapse micrographs to determine whether kinematic parameters e.g. the maximum and average migration rates of en mass fibroblast colonies are influenced by treating the cells with the above NMs. We found no evidence that Curcumin, Aloe-vera and Ginger directly influence the en mass fibroblast migration kinematics in vitro post infliction of localized mechanical damage to the cultures. However, due to the complexity of a wound healing process in vivo, these NMs may still influence the healing through other pathways

A new technique for studying directional cell migration in a hydrogel-based three-dimensional matrix for tissue engineering model systems

[[abstract]]Cell migration has a key role in biological processes e.g. malignancy, wound healing, immune response and morphogenesis. Studying migration and factors that influence it is beneficial e.g. for developing drugs to suppress metastasis, heal wounds faster or enhance the response to infection. Though the majority of the literature describes two-dimensional (2D) migration studies in culture dishes, a more realistic approach is to study migration in three-dimensional (3D) constructs. However, simple-to-implement, straight-forward standardized quantitative techniques for analysis of migration rates of cell colonies in 3D are still required in the field. Here, we describe a new model system for quantifying directional migration of colonies in a hyaluronic acid (oxi-HA) and adipic acid dihydrazide (ADH) hydrogel-based 3D matrix. We further demonstrate that our previously-reported image processing technique for measuring migration in 2D (Topman et al., 2011; 2012) is extendable for analyzing the rates of migration of cells that directionally migrate in the hydrogel and are fluorescently-stained with a 4’,6-diamidino-2-phenylindole (DAPI) nuclear stain. Together, the present experimental setup and image processing algorithm provide a standard test bench for measuring migration rates in a fully-automated, robust assay which is useful for high-throughput screening in large-scale drug evaluations, where effects on migration in a 3D matrix are sought

The influence of ischemic factors on the migration rates of cell types involved in cutaneous and subcutaneous pressure ulcers

[[abstract]]A pressure ulcer (PU) is a localized injury to the skin and/or to underlying tissues, typically over a weight-bearing bony prominence. PUs often develop in ischemic tissues. Other than being relevant to the etiology of PUs, ischemic factors such as glucose levels, acidity and temperature could potentially affect healing processes as well, particularly, the rate of damage repair. Using an in vitro cell culture model, the goal of the present study was to determine the influence of ischemic factors: low temperature (35 °C), low glucose (1 g/L) and acidic pH (6.7) on the migration rate of NIH3T3 fibroblasts, 3T3L1 preadipocytes and C2C12 myoblasts, which could all be affected by PUs. Cell migration into a local damage site, produced by crushing cells under a micro-indentor, was monitored over ~16 h under controlled temperature and pH conditions. We found that in the NIH3T3 cultures, acidosis significantly hindered the migration rate as well as delayed the times for onset and end of mass cell migration. The effects of temperature and glucose however were not significant. Additionally, under control conditions (temperature 37 °C, glucose 4.5 g/L, pH 7.6), migration rates and times differed significantly across the different cell types. The present findings motivate further studies related to the effects of pH levels on migration performances, particularly in PU where bacterial contamination-associated with an acidic environment-is involved

A study of the rise and decline of selected Labour halls in the Greater London area 1918-1979

This thesis contributes to the existing knowledge and understanding of Greater London local labour movement history, by considering it from the perspective of the meeting spaces, the labour halls, which provided a focal point for a range of activities between 1918 and 1979. Evidence, drawn from fifteen selected labour halls, illuminates a diverse range of themes, including the role of political and industrial organisations; the provision of leisure and working class education; the representation of women and the nature of gender-specific organisation; the increasing non-political usage of the premises and the diverse range of associations which using the halls. Furthermore, financial necessity precipitated a certain degree of pragmatism in the management of the halls, as evidenced by the hiring of rooms to organisations such as the Communist Party of Great Britain and the frequent sale of alcohol on the premises. Comparative studies centred upon Cambridge, Sheffield and Newport, South Wales, established that there was no indication of a specific and unique "Greater London Labour Hall" identity. The reasons for the decline of the 15 halls were more complex and extensive than the existing literature on the post-war Labour Party implies. The lack of reform at Constituency Labour Party level, the cost of maintaining the premises, and the rise of alternative meeting venues contributed to the decline of the selected premises as political spaces

Accounting Conservatism and Firm Structure in Nigeria: Evidence from Publicly Listed Manufacturing Firms

This paper assessed the relation between accounting conservatism and firm structure in Nigeria. The expo facto research design was adopted and a sample of thirty-eight (38) publicly listed manufacturing firms was employed. Data of accounting conservatism (earnings accrual) and firm structure (equity-to-asset and asset tangibility ratios) were obtained from 2012-2020. The Fixed (FE) and Random effects (RE) regression statistical technique was used. We find evidence that a firm with more conservative financial disclosure of its earnings accrual adjusts its asset structure towards the companies target more rapidly; this in particular is common for publicly listed manufacturing firms that rely on external financing for adjustment. Moreover, we found that the level of accounting conservatism positively and significantly affects the firm structure and this effect arises due to debt issuance. Overall, the paper suggests that the level of accounting conservatism plays a vital role in enhancing under-levered firms’ adjustment of asset structure of publicly listed manufacturing firms in Nigeria