Frontal Cryosectioning: An Improved Protocol for Sectioning Large Areas of Fibrous Scaffolds

Fibrous tissue engineering scaffolds, such as those produced by electrospinning, cannot achieve their clinical potential until deep cell-scaffold interactions are understood. Even the most advanced imaging techniques are limited to capturing data at depths of 100 µm due to light scatter associated with the fibers that compose these scaffolds. Conventional cross-sectional analysis provides information on relatively small volumes of space and frontal sections are difficult to generate. Current understanding of cellular penetration into fibrous scaffolds is limited predominantly to the scaffold surface. Although some information is available from cross-sections, sections vary in quality, can distort spatial scaffold properties, and offer virtually no spatial cues as to what scaffold properties instigate specific cellular responses. Without the definitive ability to understand how cells interact with the architecture of an entire scaffold it is difficult to justify scaffold modifications or in-depth cell penetration analyses until appropriate techniques are developed. To address this limitation we have developed a cryosectioning protocol that makes it possible to obtain serial frontal sections from electrospun scaffolds. Microscopic images assembled into montage images from serial sections were then used to create three-dimensional (3D) models of cellular infiltration throughout the entire scaffold

Tissue Engineering Scaffold Fabrication and Processing Techniques to Improve Cellular Infiltration

Electrospinning is a technique used to generate scaffolds composed of nano- to micron-sized fibers for use in tissue engineering. This technology possesses several key weaknesses that prevent it from adoption into the clinical treatment regime. One major weakness is the lack of porosity exhibited in most electrospun scaffolds, preventing cellular infiltration and thus hosts tissue integration. Another weakness seen in the field is the inability to physically cut electrospun scaffolds in the frontal plane for subsequent microscopic analysis (current electrospun scaffold analysis is limited to sectioning in the cross-sectional plane). Given this it becomes extremely difficult to associate spatial scaffold dynamics with a specific cellular response. In an effort to address these issues the research presented here will discuss modifications to electrospinning technology, cryosectioning technology, and our understanding of cellular infiltration mechanisms into electrospun scaffolds. Of note, the hypothesis of a potentially significant passive phase of cellular infiltration will be discussed as well as modifications to cell culture protocols aimed at establishing multiple passive infiltration phases during prolonged culture to encourage deep cellular infiltration

Integrated Fiber Electrospinning: Creating Spatially Complex Electrospun Scaffolds With Minimal Delamination

Tissue engineering scaffolds come in many shapes and sizes, however, due to difficulty manufacturing the microstructure architecture required in tissue engineering, most scaffolds are architecturally non-dynamic in nature. Because the microstructural architecture of all biological tissues is inherently complicated, non-dynamic tissue engineering scaffolds tend to be a poor platform for tissue regeneration. The current method for manufacturing dynamic tissue engineering scaffolds involves electrospinning successive layers of different fibers, an approach that exhibits no fiber transition between layers and subsequent delamination problems. In this study we aim to address the design challenges of tissue engineering scaffolds through our novel integrated fiber electrospinning technique. Developed in our lab, this electrospinning technique makes it possible to manufacture complex electrospun scaffolds tailorable to specific tissue engineering needs while minimizing delamination tendencies. Our goal is to enhance the capabilities of the tissue engineering field by increasing the manufacturable scaffold complexity and overall structural integrity of electrospun scaffolds

MO0NFALL: The Great Filter and Exo-Moon Occurrence

We observe neither life beyond Earth, nor moons around exoplanets, despite the prevalence of Earth-like planets across the galaxy. We suggest Moonfall as a possible mechanism to explain both simultaneously

Pesticide-related illness reported to and diagnosed in Primary Care: implications for surveillance of environmental causes of ill-health

BACKGROUND: In Great Britain (GB), data collected on pesticide associated illness focuses on acute episodes such as poisonings caused by misuse or abuse. This study aimed to investigate the extent and nature of pesticide-related illness presented and diagnosed in Primary Care and the feasibility of establishing a routine monitoring system. METHODS: A checklist, completed by General Practitioners (GP) for all patients aged 18+ who attended surgery sessions, identified patients to be interviewed in detail on exposures and events that occurred in the week before their symptoms appeared. RESULTS: The study covered 59320 patients in 43 practices across GB and 1335 detailed interviews. The annual incidence of illness reported to GPs because of concern about pesticide exposure was estimated to be 0.04%, potentially 88400 consultations annually, approximately 1700 per week. The annual incidence of consultations where symptoms were diagnosed by GPs as likely to be related to pesticide exposure was 0.003%, an annual estimate of 6630 consultations i.e. about 128 per week. 41% of interviewees reported using at least one pesticide at home in the week before symptoms occurred. The risk of having symptoms possibly related to pesticide exposure compared to unlikely was associated with home use of pesticides after adjusting for age, gender and occupational pesticide exposure (OR = 1.88, 95% CI 1.51 - 2.35). CONCLUSION: GP practices were diverse and well distributed throughout GB with similar symptom consulting patterns as in the Primary Care within the UK. Methods used in this study would not be feasible for a routine surveillance system for pesticide related illness. Incorporation of environmental health into Primary Care education and practice is needed

‘Remembering as Forgetting’: Organizational commemoration as a politics of recognition

This paper considers the politics of how organizations remember their past through commemorative settings and artefacts. Although these may be seen as ‘merely’ a backdrop to organizational activity, they form part of the lived experience of organizational spaces that its members enact on a daily basis as part of their routes and routines. The main concern of the paper is with how commemoration is bound up in the reflection and reproduction of hierarchies of organizational recognition. Illustrated with reference to two commemorative settings, the paper explores how organizations perpetuate a narrow set of symbolic ideals attributing value to particular forms of organizational membership while appearing to devalue others. In doing so, they communicate values that undermine attempts to achieve equality and inclusion. Developing a recognition-based critique of this process, the discussion emphasizes how commemorative settings and practices work to reproduce established patterns of exclusion and marginalization. To this end, traditional forms of commemorative portraiture that tend to close off difference are contrasted with a memorial garden, in order to explore the potential for an alternative, recognition-based ethics of organizational commemoration that is more open to the Other

Pushing the Boundaries of Amnesia and Myopia: A Critical Review of the Literature on Identity in Management and Organization Studies

The aim of this article is to review a selection of the literature on identity at work in Management and Organization Studies (MOS) in order to raise critical questions concerning what we see as the dangers of a certain amnesia and myopia. Insofar as some of the contemporary literature neglects to engage with the historical and multidisciplinary past and present, there is a tendency to leave common-sense understandings of identity unexamined, thereby reproducing everyday preoccupations with securing the self. By contrast with such rational individualism, we seek a more embodied understanding of identity, where it is a means of building our ethical engagements and capacities for community living. By failing to problematize identity, there is little recognition of how attempts to secure the self are invariably self-defeating if only because they are necessarily contingent on the other who is unpredictable and uncontrollable. The main contribution of the article is to show how this failure to interrogate identity is far from benign since it often results in reinforcing everyday preoccupations with the self that can turn into narcissism, and deflect and curtail alternative practices of embodied engagement. We trust that our deliberations will be helpful in advancing the ‘road less travelled’, where studies advance beyond taking identity for granted, and move instead towards more embodied understandings of ethical engagement