The structure and mechanics of Moso bamboo material

Bamboo has been used structurally for thousands of years. Recently, structural bamboo products analogous to wood products have become of interest both commercially and academically. This file contains original experimental results of an investigation of both the microstructure and mechanical properties of natural Moso bamboo (Phyllostachys pubescens). One of the primary aims of the investigation is to contribute data and knowledge in order to facilitate the design of products and structures with bamboo. The authors of the dataset hope making the data available allows for easy comparison and combination with others’ results, thusly furthering this goal. The raw experimental data contained in this file is the dataset presented in the article “The Structure and Mechanics of Moso Bamboo Material” in Journal of the Royal Society Interface, with which the dataset shares a name. The data is also used in “Understanding the Structural Properties of Moso Bamboo to Engineer Sustainable Structural Bamboo Products” in the 2014 World Conference Engineering Timber Engineering Proceedings. Bamboo is known to have radial and longitudinal density gradients in the tissue. In this study, the microstructural and mechanical aspects of these gradients are the primary focus. Internodes from a single culm of Moso bamboo, obtained from Bamboo Craftsman Company (Portland, Oregon), are used. Microstructural images obtained with scanning electron microscopy (SEM) are used to determine volume fractions and solid fractions of the parenchyma and vascular bundles. These images are given in this dataset. The mechanical properties measured are: the axial Young's modulus in bending, axial modulus of rupture (in bending), axial compressive strength, and radial and tangential compressive strengths. Small mechanical test specimens (for every test type) are cut at different longitudinal (internodes) and radial positions to assess the gradients’ effects on mechanical properties. Raw data from these tests with dimensions, as well as density-property summary files are given in this file. Several readme files are present within the file to explain the structure and organization of the file.This dataset is based upon work supported by the National Science Foundation OISE: 1258574

The elastic and plastic behaviour of cellular materials

Cellular materials are widespread. Some, like wood and bone, occur in nature, while others, like polymeric foams, are manmade. Because of their cellular structure, they have unusual mechanical properties: they can be stiff, yet light, and they are capable of absorbing large deflections and thus large amounts of energy. Yet their mechanical behaviour has hardly been studied: no comprehensive attempt to relate mechanical properties to structure exists. In this thesis, we have attempted to do this. We first model a cellular material as a simple, two-dimensional array of hexagonal cells and identify and analyze the mechanisms by which it deforms. From this we calculate the elastic moduli and the elastic and plastic collapse stresses for ideal two-dimensional cellular materials. The results (which we have experimentally verified) show that each of these properties depends on three parameters: a solid cell wall material property, a geometric constant, and the relative density of the cellular material raised to the power two or three. We then examine three-dimensional cellular materials. Because their geometry is irregular and very complicated, no exact analysis of their behaviour is possible. But, with our understanding of two dimensional cellular materials and how they deform, we can use dimensional arguments to analyze three-dimensional cellular materials. The results of this analysis agree well with experimental data. Finally, we have applied our understanding of cellular materials to two case studies. In the first, we have examined the structure of cork, a quasi- two-dimensional cellular material, and explained some of its mechanical properties. The second case study analyzes the problem of material selection in packaging.This work was supported by the Commonwealth Scholarship Commission

Potentially serious incidental findings in the UK Biobank Imaging Study

The increased use of imaging across research, clinical and commercial contexts has generated debate and calls for evidence on the benefits and harms of incidental findings (defined as those which are unrelated to the purpose of imaging) to inform policy and practice. Evidence on clearly non-serious incidental findings is of limited clinical usefulness; this thesis therefore focuses on potentially serious incidental findings (PSIFs), defined as those which may indicate the possibility of a condition which, if it was confirmed, would carry a real prospect of seriously threatening life span, or of having a substantial impact on major body functions or quality of life. In 2014, the UK Biobank Imaging Study began performing brain, cardiac and body magnetic resonance imaging (MRI), dual-energy X-ray absorptiometry and carotid Doppler ultrasound, and aims to image 100,000 of its population-based participants. The imaging data can be combined with extensive sociodemographic, lifestyle, physical measures, biochemical, genetic and linked healthcare data, to generate a research resource which will facilitate studies into a wide range of diseases. Due to the scale of the UK Biobank Imaging Study, PSIFs are a particularly pertinent issue. UK Biobank therefore evaluates the impact of its protocol for handling PSIFs, the data from which form the basis of this thesis. This thesis aims to provide empirical data on seven themes relating to PSIFs: their prevalence and nature; follow-up and final diagnoses; factors associated with PSIFs and with serious final diagnoses; participants’ understanding of consent to feedback of PSIFs; nonmedical impacts of feedback of PSIFs; opinions of receiving feedback of PSIFs; and the economic impact of feedback of PSIFs on hospital services. Chapter 1 outlines the scale of the challenge of incidental findings, and summarises current literature and gaps in our knowledge relating to each of the seven themes on PSIFs. Chapter 2 reviews systematically and meta-analyses published studies of brain and body MRI of apparently asymptomatic adults. Chapter 3 introduces the UK Biobank, the UK Biobank Imaging Study, and the rationale behind and protocol used to handle PSIFs in 100,000 largely asymptomatic participants: radiographer flagging of concerning images for a radiologist to review. Chapter 4 presents a study comparing two protocols to handle PSIFs in the first 1,000 imaged UK Biobank participants: radiographer flagging versus systematic radiologist review of all images. Chapter 5 investigates the factors associated with PSIFs and with serious final diagnoses. Chapter 6 examines the economic impact of feedback of PSIFs on hospital services, using linked routinely collected healthcare data. In the systematic review, pooled prevalences of PSIFs on brain, thorax, abdominal and brain and body MRI were: 1.4–1.7%; 1.3–3.0%; 1.9–4.5%; and 3.9–12.8% respectively, the upper estimates reflecting the inclusion of indeterminate findings. There was substantial heterogeneity, but few informative data on potential sources of this. Around half of PSIFs were suspected malignancies. Based on the first 7,334 participants in the UK Biobank Imaging Study (283 of whom had PSIFs), the PSIFs protocol had the largest influence on the prevalence of PSIFs and serious final diagnoses of any of the investigated factors: systematic radiologist review resulted in around 13 times more PSIFs and around four times more serious final diagnoses compared to radiographer flagging. A lower proportion of PSIFs detected by radiologists were finally diagnosed as serious compared to radiographer flagging (12% and 32% [Chapter 4 and 5]). Feedback of PSIFs resulted in substantial impacts in terms of: clinical assessments (all participants visited their general practitioner, and 90% underwent some form of other clinical assessment, mostly imaging or referral to a specialist [Chapter 4]); non-medical impacts on participants (including on emotional wellbeing, insurance and finances and work and activities in 17%, 9% and 6% respectively [Chapter 4]); and hospital service use and cost (81% of cases with PSIFs generated some hospital use and costs, which had increased compared to controls, and to cases’ hospital use and costs during the year before feedback of a PSIF [Chapter 6]). Importantly, as around 80% of PSIFs turned out not to be serious (Chapters 2, 4 and 5), many of these impacts may be unnecessary. Despite these negative impacts, the vast majority of participants were glad to have received feedback of a PSIF and to have taken part in the imaging study (98% and 99% respectively), although almost a quarter changed their minds over time about whether or not feedback should always be given. Around a quarter of participants incorrectly thought they could choose to receive feedback and UK Biobank has improved its consent materials accordingly (Chapter 4). Feedback of PSIFs impacts on participants and publicly-funded health services (and in turn patients in need); most PSIFs turn out not to be serious and many of these impacts may be unnecessary. Researchers can substantially influence these impacts via IFs policies, which must be designed to minimise unnecessary harms, and be clearly explained to participants to facilitate informed consent. These, and other implications of this thesis are further described in Chapter 7, which also discusses the results in the context of the broader literature, outlines the strengths and limitations of this thesis, and suggests directions for future work

MENISCUS SMC dataset

The study took place in four secondary schools in Entebbe sub-district, Uganda. Acceptability, perceptions and knowledge of safe male circumcision were assessed through a cross-sectional quantitative survey of 210 participants recruited from Forms 2 and 3. The dataset contains records of male students (one record per row), aged 13-25 (median ages 16-17 years) recruited in October and November 2015. It encompasses enrolment, treatment process (including therapy quality), clinical/other outcome data, and cost-effectiveness data

A protocol for a systematic review of clinical guidelines and published systematic reviews on the early detection of oral cancer

Background: The predicted increase in incidence of oral cavity cancer (OCC) coupled with high mortality and poor prognosis – particularly when diagnosed at a late/advanced stage – highlights the need for prevention and early detection/screening to reverse these trends. Dental healthcare professionals in primary care settings have a pivotal role in this effort. Aim: The aim of this protocol is to detail the process for assessing the evidence for the best practice and methods of early detection/screening for OCC in primary care dental settings by undertaking a systematic review of global clinical guidelines and published systematic reviews. Method: Searches for clinical guidelines and systematic reviews will be conducted in the following databases: Cochrane library, Medical Literature Analysis and Retrieval System Online (Ovid), Excerpta Medical dataBASE, PubMed, Turning Research into Practice, SCOPUS and Web of Science Core Collection. Our search will extend to include Google Scholar and international professional organizations/associations websites. In addition, we will handsearch the bibliographies and undertake citation searches of the selected papers. Quality appraisal will be undertaken using the Appraisal of Guidelines for Research and Evaluation version II instrument for the clinical guidelines and both A MeaSurement Tool to Assess Systematic Reviews and Risk of Bias in Systematic Reviews tools for the systematic reviews. A narrative synthesis approach will be used to assess the evidence of extracted data, primarily taking account of quality appraisal and recency of publication. Discussion: The synthesis of evidence will determine best practice for OCC early detection/screening by primary care dental healthcare professionals and will evaluate the relationship between clinical guidelines and the evidence base available from systematic reviews in this area

Towards equality: gender representation at the Royal College of Radiologists’ Annual Scientific Meeting 2014-2021

Background: Conferences facilitate career advancement, but gender imbalances in public fora may negatively impact both women and men, and society. We aimed to describe the gender distribution of presenters at the UK’s 2014-2021 Royal College of Radiologists’ (RCR) Annual Scientific Meeting. Methods: We extracted data on presenter name, role and session type from meeting programmes. We classified gender as male or female using names, records or personal pronouns, accepting the limitations of these categories. We classified roles by prestige: lead, other (speakers and workshop faculty), proffered paper or poster presenters. We calculated odds ratios (OR) and 95% confidence intervals (CI) for associations between gender and binary outcomes using logistic regression.  Results: Women held 1,059 (37.5%) of 2,826 conference roles and presented 9/27 keynotes. Compared to men, women were less likely to hold other roles such as speakers and workshop faculty (OR 0.72 95% CI 0.61-0.83), and more likely to present posters (OR 1.49 95% CI 1.27-1.76). There were 60 male-only and eight women-only multi-presenter sessions. Sessions led by women had higher proportions of women speakers. The odds of roles being held by women increased during online meetings during COVID in 2020 and 2021 (OR 1.61, 95% CI 1.36-1.91) compared to earlier years. Conclusion: The proportion of women presenters and keynote speakers reflects that of RCR membership, but not of wider society. Disadvantage starts from the earliest career stages, prejudicing career opportunities. Efforts to improve inclusion and diversity are needed; focusing on lead roles and hybrid online/in-person formats may accelerate change

Validation of the posttraumatic stress disorder checklist - 5 (PCL-5) in a primary care population with high HIV prevalence in Zimbabwe.

BACKGROUND: There is a dearth of validated tools measuring posttraumatic stress disorder (PTSD) in low and middle-income countries in sub-Saharan Africa. We validated the Shona version of the PTSD Checklist for DSM-5 (PCL-5) in a primary health care clinic in Harare, Zimbabwe. METHOD: Adults aged 18 and above attending the clinic were enrolled over a two-week period in June 2016. After obtaining written consent, trained research assistants administered the tool to eligible participants. Study participants were then interviewed independently using the Clinician Administered PTSD Scale (CAPS-5) as the gold standard by one of five doctors with training in mental health. RESULT: A total of 204 participants were assessed. Of these, 91 (44.6%) were HIV positive, 100 (49%) were HIV negative, while 13 (6.4%) did not know their HIV status. PTSD was diagnosed in 40 (19.6%) participants using the gold standard procedure. Using the PCL-5 cut-off of ≥33, sensitivity and specificity were 74.5% (95%CI: 60.4-85.7); 70.6% (95%CI: 62.7-77.7), respectively. The area under the ROC curve was 0.78 (95%CI: 0.72-0.83). The Shona version of the PCL-5 demonstrated good internal consistency (Cronbach's alpha = 0.92). CONCLUSION: The PCL-5 performed well in this population with a high prevalence of HIV. There is need to explore ways of integrating screening tools for PTSD in interventions delivered by lay health workers in low and middle-income countries (LMIC)

Development and mechanical characterization of novel ceramic foams fabricated by gel-casting

Porous ceramic materials are of considerable interest for a variety of chemical and industrial applications in extremely harsh conditions, particularly at very high temperatures for long time periods. A combined gel-casting-fugitive phase process employing agar as a natural gelling agent and polyethylene spheres as pore formers was exploited to produce porous ceramic bodies. Alumina and alumina–zirconia powders were used to prepare samples having a porosity of about 65–70–75 vol%. The composite powder was produced by a surface modification route, i.e. by coating a well-dispersed alpha-alumina powder with a zirconium chloride aqueous solution. On thermal treatment, ultra-fine tetragonal zirconia grains were formed on the surface of the alumina particles. SEM observations and image analysis were used to characterize the microstructure of porous samples and uniaxial compressive tests were carried out to measure their mechanical behavior

Prevalence and correlates of probable common mental disorders in a population with high prevalence of HIV in Zimbabwe

BackgroundIn 2014 close to 10 million people living with HIV (PLWH) in sub-Saharan Africa were on highly active anti-retroviral therapy (HAART). The incidence of non-communicable diseases has increased markedly in PLWH as mortality is reduced due to use of HAART. Common mental disorders (CMD) are highly prevalent in PLWH. We aimed to determine factors associated with probable CMD and depression, assessed by 2 locally validated screening tools in a population with high prevalence of HIV in Harare, Zimbabwe.MethodsWe carried out a cross-sectional survey of a systematic random sample of patients utilizing the largest primary health care facility in Harare. Adults aged ≥18years attending over a 2-week period were eligible, excluding those who were critically ill or unable to give written informed consent. Two locally validated screening tools the Shona symptom questionnaire (SSQ-14) and the Patient Health Questionnaire (PHQ-9) were administered by trained research assistants to identify probable CMD and depression.ResultsOf the 264 participants, 165 (62.5%) were PLWH, and 92% of these were on HAART. The prevalence of probable CMD (SSQ14 > = 9) and depression (PHQ9 > = 11) were higher among people living with HIV than among those without HIV (67.9 and 68.5% vs 51.4 and 47.2% respectively). Multivariable analysis showed female gender and recent negative life events to be associated with probable CMD and depression among PLWH (gender: OR = 2.32 95 % CI:1.07–5.05; negative life events: OR = 4.14; 95 % CI 1.17–14.49) and with depression (gender: OR = 1.84 95 % CI:0.85–4.02; negative life events: OR = 4.93.; 95 % CI 1.31–18.50)ConclusionElevated scores on self-report measures for CMD and depression are highly prevalent in this high HIV prevalence population. There is need to integrate packages of care for CMD and depression in existing primary health care programs for HIV/AIDS

The effect of pore size on cell adhesion in collagen-GAG scaffolds.

The biological activity of scaffolds used in tissue engineering applications hypothetically depends on the density of available ligands, scaffold sites at which specific cell binding occurs. Ligand density is characterized by the composition of the scaffold, which defines the surface density of ligands, and by the specific surface area of the scaffold, which defines the total surface of the structure exposed to the cells. It has been previously shown that collagen-glycosaminoglycan (CG) scaffolds used for studies of skin regeneration were inactive when the mean pore size was either lower than 20 microm or higher than 120 microm (Proc. Natl. Acad. Sci., USA 86(3) (1989) 933). To study the relationship between cell attachment and viability in scaffolds and the scaffold structure, CG scaffolds with a constant composition and solid volume fraction (0.005), but with four different pore sizes corresponding to four levels of specific surface area were manufactured using a lyophilization technique. MC3T3-E1 mouse clonal osteogenic cells were seeded onto the four scaffold types and maintained in culture. At the experimental end point (24 or 48 h), the remaining viable cells were counted to determine the percent cell attachment. A significant difference in viable cell attachment was observed in scaffolds with different mean pore sizes after 24 and 48 h; however, there was no significant change in cell attachment between 24 and 48 h for any group. The fraction of viable cells attached to the CG scaffold decreased with increasing mean pore size, increasing linearly (R2 = 0.95, 0.91 at 24 and 48 h, respectively) with the specific surface area of the scaffold. The strong correlation between the scaffold specific surface area and cell attachment indicates that cell attachment and viability are primarily influenced by scaffold specific surface area over this range (95.9-150.5 microm) of pore sizes for MC3T3 cells