637 research outputs found

    Crossing Conceptual Boundaries XII, 2022

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    ISSN: 2041-9090 Crossing Conceptual Boundaries PhD Annual Yearbook New Series Volume XII A peer-reviewed graduate publication, School of Education & Communities, UEL, U

    Validation of low-dose lung cancer PET-CT protocol and PET image improvement using machine learning

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    PURPOSE: To conduct a simplified lesion-detection task of a low-dose (LD) PET-CT protocol for frequent lung screening using 30% of the effective PETCT dose and to investigate the feasibility of increasing clinical value of low-statistics scans using machine learning. METHODS: We acquired 33 SD PET images, of which 13 had actual LD (ALD) PET, and simulated LD (SLD) PET images at seven different count levels from the SD PET scans. We employed image quality transfer (IQT), a machine learning algorithm that performs patch-regression to map parameters from low-quality to high-quality images. At each count level, patches extracted from 23 pairs of SD/SLD PET images were used to train three IQT models - global linear, single tree, and random forest regressions with cubic patch sizes of 3 and 5 voxels. The models were then used to estimate SD images from LD images at each count level for 10 unseen subjects. Lesion-detection task was carried out on matched lesion-present and lesion-absent images. RESULTS: LD PET-CT protocol yielded lesion detectability with sensitivity of 0.98 and specificity of 1. Random forest algorithm with cubic patch size of 5 allowed further 11.7% reduction in the effective PETCT dose without compromising lesion detectability, but underestimated SUV by 30%. CONCLUSION: LD PET-CT protocol was validated for lesion detection using ALD PET scans. Substantial image quality improvement or additional dose reduction while preserving clinical values can be achieved using machine learning methods though SUV quantification may be biased and adjustment of our research protocol is required for clinical use

    The Induction of IgM and IgG Antibodies against HLA or MICA after Lung Transplantation

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    The production of IgG HLA antibodies after lung transplantation (LTx) is considered to be a major risk factor for the development of chronic rejection, represented by the bronchiolitis obliterans syndrome (BOS). It has recently been observed that elevated levels of IgM HLA antibodies also correlates with the development of chronic rejection in heart and kidney transplantation. This study investigates the relationship between IgM and IgG antibodies against HLA and MICA after lung transplantation. Serum was collected from 49 patients once prior to transplantation and monthly for up to 1 year after lung transplantation was analyzed by Luminex to detect IgM and IgG antibodies against HLA and MICA. The presence of either IgM or IgG HLA and/or MICA antibodies prior to or after transplantation was not related to survival, gender, primary disease, or the development of BOS. Additionally, the production of IgG alloantibodies was not preceded by an increase in levels of IgM, and IgM levels were not followed by an increase in IgG. Under current immune suppressive regimen, although the presence of IgM antibodies does not correlate with BOS after LTx, IgM high IgG low HLA class I antibody titers were observed more in patients with BOS compared to patients without BOS

    Clinical and Epidemiological Characteristics of 1,420 European Patients with mild-to-moderate Coronavirus Disease 2019

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    Background: The clinical presentation of European patients with mild-to-moderate Covid-19 infection is still unknown. Objective: To study the clinical presentation of Covid-19 in Europe. Methods: Patients with positive diagnosis of Covid-19 were recruited from 18 European hospitals. Epidemiological and clinical data were obtained through a standardized questionnaire. Bayesian analysis was used for analyzing the relationship between outcomes. Results: 1,420 patients completed the study (962 females, 30.7% of health care workers). The mean age of patients was 39.17\ub112.09 years. The most common symptoms were headache (70.3%), loss of smell (70.2%), nasal obstruction (67.8%), cough (63.2%), asthenia (63.3%), myalgia (62.5%), rhinorrhea (60.1%), gustatory dysfunction (54.2%) and sore throat (52.9%). Fever was reported by on 45.4%. The mean duration of Covid-19 symptoms of mild-to-moderate cured patients was 11.5\ub15.7 days. The prevalence of symptoms significantly varied according to age and sex. Young patients more frequently had ear, nose, and throat complaints, whereas elderly individuals often presented fever, fatigue and loss of appetite. Loss of smell, headache, nasal obstruction and fatigue were more prevalent in female patients. The loss of smell was a key symptom of mild-to-moderate Covid19 patients and was not associated with nasal obstruction and rhinorrhea. Loss of smell persisted at least 7 days after the disease in 37.5% of cured patients. Conclusion: The clinical presentation of mild-to-moderate Covid-19 substantially varies according to the age and the sex characteristics of patients. Olfactory dysfunction seems to be an important underestimated symptom of mild-to-moderate Covid-19 that needs to be recognized as such by the WHO

    Two-Week versus Six-Month Sampling Interval in a Short-Term Natural History Study of Oral HPV Infection in an HIV-Positive Cohort

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    BACKGROUND: Oral HPV infections detected six-months apart were compared to those detected bi-weekly, in an HIV-positive cohort, during the intervening months to elucidate systematic biases introduced into natural history studies by sampling interval. METHODS: Fourteen consecutive oral rinse samples were collected every two weeks for six months from an HIV-positive cohort (n = 112) and evaluated for the presence of 37 HPV types. The cumulative probability of type-specific HPV detection at visits 1 through 14 was determined as a function of infection categorized at visits 1 and 14 as persistent, newly detected, cleared or absent. Transition models were used to evaluate the effect of HPV viral load (measured by RT-PCR for HPV 16, 18, 31, 33, 35) on infection persistence. RESULTS: The average point prevalence of oral HPV infection was similar at two-week and six-month sampling intervals (45% vs. 47%, p = 0.52), but cumulative prevalence was higher with the former (82% vs. 53%, p<0.001) as was the cumulative prevalence of type-specific infections (9.3% vs 3.8%, p<0.0001). Type-specific infections persistent under a six-month sampling interval had a high probability (0.93, 95%CI 0.83-0.98) of detection at 50% or more of the intervening visits and infections that were absent had a high probability (0.94, 95% CI 0.93-0.95) of no interval detection. The odds of detection at any visit significantly increased for each unit increase in HPV viral load at the previous visit. CONCLUSIONS: Six-month sampling is appropriate to model factors associated with type-specific oral HPV infection persistence but may misclassify HPV-exposed individuals as unexposed

    Paradox in the pursuit of a critical theorization of the development of self in family relationships

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    This article starts with my dissatisfaction with the post-structuralist treatment of the production of subjectivity within regulatory discourses and practices due to its neglect of psychological processes. Taking starting points from within the history set out in the previous article, it highlights the paradox for critical psychologists like myself involved in both applying a post-structuralist critique to 'psy' discourses and trying to theorize subjectivity in a way that goes beyond the dualism of individual and society, of psychology and sociology. The relational, or intersubjective, approach to self that originates in object relations psychoanalysis as it emerged in the mid-20th-century UK is central to both of these activities; object of the former and resource for the latter. I explore the paradox that this creates for critical psychology, both epistemological and ontological. In aiming to provide a psycho-social account of self in family relationships, I deploy the radical conceptualisation of intersubjectivity initiated in British object relations theory as a way of going beyond both the individualized self and the neglect of psychological processes in constructionist theorizing subjectivity

    HPV-Associated Head and Neck Cancer: Molecular and Nano-Scale Markers for Prognosis and Therapeutic Stratification

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    Over the last 10 years, it has become clear that patients with head and neck cancer can be stratified into two distinct subgroups on the basis of the etiology of their disease. Patients with human papillomavirus-related cancers have significantly better survival rates and may necessitate different therapeutic approaches than those with tobacco and/or alcohol related cancers. This review discusses the various biomarkers currently in use for identification of patients with HPV-positive cancers with a focus on the advantages and limitations of molecular and nano-scale markers
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