Illumination uniformity in endoscopic imaging

Standardised endoscopic digital images were taken and analysed using an image analysis software (National Instruments Vision Assistant version 7.1.1). The luminance plane was extracted and the pixel intensity distribution was determined along a horizontal line at the position of highest average intensity (centroid). The data was exported to MS Excel and the pixel intensity (y-axis) was plotted against pixel position (x-axis). A trendline using a 2nd order polynomial curve was fitted to each data set. The resultant equation for each curve was compared with equations obtained from other images taken under various illumination conditions and settings

Development of Longitudinal Split Failure in White-Rotted Aspen (Populus Tremuloides Michx.)

Longitudinal splits and associated smooth fracture planes were often noted along the growth ring boundaries of aspen, Populus tremuloides Michx., which were impact-loaded on the tangential plane, after decay by Trametes versicolor (L.: Fr.) Pilat, and Bjerkandera adusta (Willd.: Fr.) Karst. To characterize this failure pattern, scanning (SEM) and transmission (TEM) electron microscopy were employed. Results showed that this failure is a result of longitudinal fracture lines that cut through the parenchyma cell-wall layers (transwall failure) and opened the lumens. These parenchyma cells were preferentially invaded by fungal hyphae early (weight loss = 10%) in the degradation process. Prominent on the fracture planes was evidence of parenchyma cross walls perpendicular to the fiber axis, fungal hyphae, and associated hyphal sheaths. Localized fracturing along the parenchyma cells suggests that fungal invasion and degradation patterns influence the development and morphology of longitudinal fracture in wood

Sequential simulation (SqS) of clinical pathways: a tool for public and patient engagement in point-of-care diagnostics

Objectives: Public and patient engagement (PPE) is fundamental to healthcare research. To facilitate effective engagement in novel point-of-care tests (POCTs), the test and downstream consequences of the result need to be considered. Sequential simulation (SqS) is a tool to represent patient journeys and the effects of intervention at each and subsequent stages. This case study presents a process evaluation of SqS as a tool for PPE in the development of a volatile organic compound-based breath test POCT for the diagnosis of oesophagogastric (OG) cancer. Setting: Three 3-hour workshops in central London. Participants: 38 members of public attended a workshop, 26 (68%) had no prior experience of the OG cancer diagnostic pathway. Interventions: Clinical pathway SqS was developed from a storyboard of a patient, played by an actor, noticing symptoms of oesophageal cancer and following a typical diagnostic pathway. The proposed breath testing strategy was then introduced and incorporated into a second SqS to demonstrate pathway impact. Facilitated group discussions followed each SqS. Primary and secondary outcome measures: Evaluation was conducted through pre-event and postevent questionnaires, field notes and analysis of audiovisual recordings. Results: 38 participants attended a workshop. All participants agreed they were able to contribute to discussions and like the idea of an OG cancer breath test. Five themes emerged related to the proposed new breath test including awareness of OG cancer, barriers to testing and diagnosis, design of new test device, new clinical pathway and placement of test device. 3 themes emerged related to the use of SqS: participatory engagement, simulation and empathetic engagement, and why participants attended. Conclusions: SqS facilitated a shared immersive experience for participants and researchers that led to the coconstruction of knowledge that will guide future research activities and be of value to stakeholders concerned with the invention and adoption of POCT

Gold nanorod reshaping in vitro and in vivo using a continuous wave laser

Funding for this project was provided by ERC grant 242991 (D. Elson), and by Cancer Research UK via the CRUK Cancer Imaging Centre at the Institute of Cancer Research (ICR) to J. Bamber. We acknowledge an ERC starting grant (project number 257182) to A. Porter, and BRC funding (project number P46143) to A. Porter, D. Elson and P. Ruenraroengsak. We acknowledge NHS funding to the NIHR Biomedical Research Centre at The Royal Marsden (J. Bamber) and at Imperial College London, as well as support provided by the Cancer Research UK Imperial Centre.Gold nanorods (GNRs) are increasingly being investigated for cancer theranostics as they possess features which lend themselves in equal measures as contrast agents and catalysts for photothermal therapy. Their optical absorption spectral peak wavelength is determined by their size and shape. Photothermal therapy using GNRs is typically established using near infrared light as this allows sufficient penetration into the tumour matrix. Continuous wave (CW) lasers are the most commonly applied source of near infrared irradiation on GNRs for tumour photothermal therapy. It is perceived that large tumours may require fractionated or prolonged irradiation. However the true efficacy of repeated or protracted CW irradiation on tumour sites using the original sample of GNRs remains unclear. In this study spectroscopy and transmission electron microscopy are used to demonstrate that GNRs reshape both in vitro and in vivo after CW irradiation, which reduces their absorption efficiency. These changes were sustained throughout and beyond the initial period of irradiation, resulting from a spectral blue-shift and a considerable diminution in the absorption peak of GNRs. Solid subcutaneous tumours in immunodeficient BALB/c mice were subjected to GNRs and analysed with electron microscopy pre- and post-CW laser irradiation. This phenomenon of thermally induced GNR reshaping can occur at relatively low bulk temperatures, well below the bulk melting point of gold. Photoacoustic monitoring of GNR reshaping is also evaluated as a potential clinical aid to determine GNR absorption and reshaping during photothermal therapy. Aggregation of particles was coincidentally observed following CW irradiation, which would further diminish the subsequent optical absorption capacity of irradiated GNRs. It is thus established that sequential or prolonged applications of CW laser will not confer any additional photothermal effect on tumours due to significant attenuations in the peak optical absorption properties of GNRs following primary laser irradiation.Publisher PDFPeer reviewe

Real-Time Studies of Iron Oxalate-Mediated Oxidation of Glycolaldehyde as a Model for Photochemical Aging of Aqueous Tropospheric Aerosols

The complexation of iron (III) with oxalic acid in aqueous solution yields a strongly absorbing chromophore that undergoes efficient photodissociation to give iron (II) and the carbon dioxide anion radical. Importantly, iron (III) oxalate complexes absorb near-UV radiation (λ > 350 nm), providing a potentially powerful source of oxidants in aqueous tropospheric chemistry. Although this photochemical system has been studied extensively, the mechanistic details associated with its role in the oxidation of dissolved organic matter within aqueous aerosol remain largely unknown. This study utilizes glycolaldehyde as a model organic species to examine the oxidation pathways and evolution of organic aerosol initiated by the photodissociation of aqueous iron (III) oxalate complexes. Hanging droplets (radius 1 mm) containing iron (III), oxalic acid, glycolaldehyde, and ammonium sulfate (pH ~ 3) are exposed to irradiation at 365 nm and sampled at discrete time points utilizing field-induced droplet ionization mass spectrometry (FIDI-MS). Glycolaldehyde is found to undergo rapid oxidation to form glyoxal, glycolic acid, and glyoxylic acid, but the formation of high molecular weight oligomers is not observed. For comparison, particle-phase experiments conducted in a laboratory chamber explore the reactive uptake of gas-phase glycolaldehyde onto aqueous seed aerosol containing iron and oxalic acid. The presence of iron oxalate in seed aerosol is found to inhibit aerosol growth. These results suggest that photodissociation of iron (III) oxalate can lead to the formation of volatile oxidation products in tropospheric aqueous aerosols