112 research outputs found

    Integration of domain and resource-based reasoning for real-time control in dynamic environments

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    A real-time software controller that successfully integrates domain-based and resource-based control reasoning to perform task execution in a dynamically changing environment is described. The design of the controller is based on the concept of partitioning the process to be controlled into a set of tasks, each of which achieves some process goal. It is assumed that, in general, there are multiple ways (tasks) to achieve a goal. The controller dynamically determines current goals and their current criticality, choosing and scheduling tasks to achieve those goals in the time available. It incorporates rule-based goal reasoning, a TMS-based criticality propagation mechanism, and a real-time scheduler. The controller has been used to build a knowledge-based situation assessment system that formed a major component of a real-time, distributed, cooperative problem solving system built under DARPA contract. It is also being employed in other applications now in progress

    Behavioral Analysis of the Escape Response in the Juvenile Lobster Homarus Americanus Over the Molt Cycle

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    1. Components of the escape response of the American lobster were compared over the molt cycle. Number of tailflips, frequency, duration and distance were measured. Velocity, acceleration, force and work were computed from the above measurements, using time-lapse video-recordings of escaping lobsters. 2. Soft-shelled postmolt lobsters (stage B) traveled further, spent more time tailflipping and performed a larger number of tailflips than hard-shelled premolt lobsters (stage D). Hard-shelled lobsters had a more forceful initial power swim, achieved a higher overall velocity and acceleration and, therefore, produced more forceful swims with greater energy expenditure (measured by work output) than soft-shelled animals. 3. Among hard-shelled lobsters, velocity, acceleration, force and work fell off markedly in the latter part of their subsequent swims as a consequence of the prolonged duration and reduced frequency of these swims. Soft-shelled lobsters sustained their swimming velocity, acceleration, force and work for their entire subsequent swimming response. 4. There are likely to be large molt-related differences in energy metabolism, endocrinology and nerve and muscle physiology which lead to the observed differences in the escape response

    A proteomic time course through the differentiation of human induced pluripotent stem cells into hepatocyte-like cells.

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    Numerous in vitro models endeavour to mimic the characteristics of primary human hepatocytes for applications in regenerative medicine and pharmaceutical science. Mature hepatocyte-like cells (HLCs) derived from human induced pluripotent stem cells (hiPSCs) are one such in vitro model. Due to insufficiencies in transcriptome to proteome correlation, characterising the proteome of HLCs is essential to provide a suitable framework for their continual optimization. Here we interrogated the proteome during stepwise differentiation of hiPSCs into HLCs over 40 days. Whole cell protein lysates were collected and analysed using stabled isotope labelled mass spectrometry based proteomics. Quantitative proteomics identified over 6,000 proteins in duplicate multiplexed labelling experiments across two different time course series. Inductive cues in differentiation promoted sequential acquisition of hepatocyte specific markers. Analysis of proteins classically assigned as hepatic markers demonstrated trends towards maximum relative abundance between differentiation day 30 and 32. Characterisation of abundant proteins in whole cells provided evidence of the time dependent transition towards proteins corresponding with the functional repertoire of the liver. This data highlights how far the proteome of undifferentiated precursors have progressed to acquire a hepatic phenotype and constructs a platform for optimisation and improved maturation of HLC differentiation

    Functional and structural brain network correlates of visual hallucinations in Lewy body dementia

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    Visual hallucinations are a common feature of Lewy body dementia. Previous studies have shown that visual hallucinations are highly specific in differentiating Lewy body dementia from Alzheimer’s disease dementia and Alzheimer-Lewy body mixed pathology cases. Computational models propose that impairment of visual and attentional networks is aetiologically key to the manifestation of visual hallucinations symptomatology. However, there is still a lack of experimental evidence on functional and structural brain network abnormalities associated with visual hallucinations in Lewy body dementia. We used EEG source localisation and Network Based Statistics to assess differential topographical patterns in Lewy body dementia between 25 participants with visual hallucinations and 17 participants without hallucinations. Diffusion tensor imaging was used to assess structural connectivity between thalamus, basal forebrain and cortical regions belonging to the functionally affected network component in the hallucinating group, as assessed with Network Based Statistics. Number of white matter streamlines within the cortex and between subcortical and cortical regions was compared between hallucinating and not hallucinating groups and correlated with average EEG source connectivity of the affected subnetwork. Moreover, modular organisation of the EEG source network was obtained, compared between groups, and tested for correlation with structural connectivity. Network analysis showed that compared to non-hallucinating patients, those with hallucinations feature consistent weakened connectivity within the visual ventral network, and between this network and default mode and ventral attentional networks, but not between or within attentional networks. The occipital lobe was the most functionally disconnected region. Structural analysis yielded significantly affected white matter streamlines connecting the cortical regions to the nucleus basalis of Meynert and the thalamus in hallucinating compared to not hallucinating patients. The number of streamlines in the tract between the basal forebrain and the cortex correlated with cortical functional connectivity in non-hallucinating patients, whilst a correlation emerged for the white matter streamlines connecting the functionally affected cortical regions in the hallucinating group. This study proposes, for the first time, differential functional networks between hallucinating and not hallucinating Lewy body dementia patients, and provides an empirical evidence for existing models of visual hallucinations. Specifically, the outcome of the present study shows that the hallucinating condition is associated with functional network segregation in Lewy body dementia and supports the involvement of the cholinergic system as proposed in the current literature

    Experiences and perceptions of people with headache: a qualitative study

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    BACKGROUND: Few qualitative studies of headache have been conducted and as a result we have little in-depth understanding of the experiences and perceptions of people with headache. The aim of this paper was to explore the perceptions and experiences of individuals with headache and their experiences of associated healthcare and treatment. METHODS: A qualitative study of individuals with headache, sampled from a population-based study of chronic pain was conducted in the North-East of Scotland, UK. Seventeen semi-structured interviews were conducted with adults aged 65 or less. Interviews were analysed using the Framework approach utilising thematic analysis. RESULTS: Almost every participant reported that they were unable to function fully as a result of the nature and unpredictability of their headaches and this had caused disruption to their work, family life and social activities. Many also reported a negative impact on mood including feeling depressed, aggressive or embarrassed. Most participants had formed their own ideas about different aspects of their headache and several had searched for, or were seeking, increased understanding of their headache from a variety of sources. Many participants reported that their headaches caused them constant worry and anguish, and they were concerned that there was a serious underlying cause. A variety of methods were being used to manage headaches including conventional medication, complementary therapies and self-developed management techniques. Problems associated with all of these management strategies emerged. CONCLUSION: Headache has wide-ranging adverse effects on individuals and is often accompanied by considerable worry. The development of new interventions or educational strategies aimed at reducing the burden of the disorder and associated anxiety are needed

    Randomised controlled trial of school-based humanistic counselling for emotional distress in young people: Feasibility study and preliminary indications of efficacy

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    The purpose of this study was to test the feasibility of a randomised controlled trial comparing six weeks of humanistic school-based counselling versus waiting list in the reduction of emotional distress in young people, and to obtain initial indications of efficacy. Following a screening procedure, young people (13 - 15 years old) who experienced emotional distress were randomised to either humanistic counselling or waiting list in this multi-site study. Outcomes were assessed using a range of self-report mental health measures, with the emotional symptoms subscale of the Strengths and Difficulties Questionnaire (SDQ) acting as the primary outcome indicator. Recruitment procedures were successful, with 32 young people consenting to participate in the trial and 27 completing endpoint measures. Trial procedures were acceptable to all involved in the research. No significant differences were found between the counselling and waiting list groups in reductions in levels of emotional symptoms (Hedges' g = 0.03), but clients allocated to counselling showed significantly greater improvement in prosocial behaviour (g = 0.89) with an average effect size (g) across the nine outcome measures of 0.25. Participants with higher levels of depressive symptoms showed significantly greater change. This study suggested that a randomised controlled trial of counselling in schools is acceptable and feasible, although initial indications of efficacy are mixed

    A qualitative study of patients' views on quality of primary care consultations in Hong Kong and comparison with the UK CARE Measure

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    <b>Background</b> Patients' priorities and views on quality care are well-documented in Western countries but there is a dearth of research in this area in the East. The aim of the present study was to explore Chinese patients' views on quality of primary care consultations in Hong Kong and to compare these with the items in the CARE measure (a process measure of consultation quality widely used in the UK) in order to assess the potential utility of the CARE measure in a Chinese population.<p></p> <b>Methods</b> Individual semi-structured interviews were conducted on 21 adult patients from 3 different primary care clinics (a public primary healthcare clinic, a University health centre, and a private family physician's clinic). Topics discussed included expectations, experiences, and views about quality of medical consultations. Interviews were typed verbatim, and a thematic approach was taken to identify key issues. These identified issues were then compared with the ten CARE measure items, using a CARE framework: Connecting (Care Measure items 1–3), Assessing (item 4), Responding (items 5,6), and Empowering (items 7–10).<p></p> <b>Results</b> Patients judged doctors in terms of both the process of the consultation and the perceived outcomes. Themes identified that related to the interpersonal process of the consultation fitted well under the CARE framework; Connecting and communicating (18/21 patients), Assessing holistically (10/21 patients), Responding (18/21 patients) and Empowering (19/21 patients). Patients from the public clinic, who were generally of lower socio-economic status, were least likely to expect holistic care or empowerment. Two-thirds of patients also judged doctors on whether they performed an adequate physical examination, and three-quarters on the later outcomes of consultation (in terms of relief or cure and/or side-effects of prescribed drugs).<p></p> <b>Conclusion</b> These findings suggest that Chinese patients in Hong Kong value engaged, empathic primary care doctors and judge the quality of consultations largely on these human skills and the attitudes and values that underpin them, as well as on the perceived outcomes of treatment. The match between themes relating to consultation process and the CARE Measure items suggests utility of this measure in this population, but further quantitative validation is required

    Standardization of natural mycolic acid antigen composition and production for use in biomarker antibody detection to diagnose active tuberculosis

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    This research article published by Elsevier B.V., 2016Mycobacterium tuberculosis, the causative agent of tuberculosis, is characterized by the abundance of species specific, antigenic cell wall lipids called mycolic acids. These wax-like molecules all share an identical, amphiphilic mycolic motif, but have different functional groups in a long hydrophobic hydrocarbon mero-chain that divide them into three main classes: alpha-, keto- and methoxy-mycolic acids. Whereas alpha-mycolic acids constitutively maintain an abundance of around 50%, the ratio of methoxy- to keto-mycolic acid types may vary depending on, among other things, the growth stage of M. tuberculosis. In human patients, antibodies to mycolic acids have shown potential as diagnostic serum biomarkers for active TB. Variations in mycolic acid composition affect the antigenic properties and can potentially compromise the precision of detection of anti-mycolic acids antibodies in patient sera to natural mixtures. We demonstrate this here with combinations of synthetic mycolic acid antigens, tested against TB patient and control sera. Combinations of methoxy- and α-mycolic acids are more antigenic than combinations of keto- and α-mycolic acids, showing the former to give a more sensitive test for TB biomarker antibodies. Natural mixtures of mycolic acids isolated from mature cultures of M. tuberculosis H37Rv give the same sensitivity as that with synthetic methoxy- and α-mycolic acids in combination, in a surface plasmon resonance inhibition biosensor test. To ensure that the antigenic activity of isolates of natural mycolic acids is reproducible, we cultured M. tuberculosis H37Rv on Middlebrook 7H10 solid agar plates to stationary growth phase in a standardized, optimal way. The proportions of mycolic acid classes in various batches of the isolates prepared from these cultures were compared to a commercially available natural mycolic acid isolate. LC-MS/MS and NMR data for quantitation of mycolic acids class compositions show that the variation in batches is small, suggesting that the quality of the results for anti-mycolic acid antibody detection in the TB patients should not be affected by different batches of natural mycolic acid antigens if prepared in a standard way

    SARS-CoV-2 Vaccine Immunogenicity in Patients with Gastrointestinal Cancer Receiving Systemic Anti-Cancer Therapy.

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    INTRODUCTION: Patients with gastrointestinal (GI) cancers have an increased risk of serious complications and death from SARS-CoV-2 infection. The immunogenicity of vaccines in patients with GI cancers receiving anti-cancer therapies is unclear. We conducted a prospective study to evaluate the prevalence of neutralizing antibodies in a cohort of GI cancer patients receiving chemotherapy following SARS-CoV-2 vaccination. MATERIALS AND METHODS: Between September 2020 and April 2021, patients with cancer undergoing chemotherapy were enrolled. At baseline (day 0), days 28, 56, and 84, we assessed serum antibodies to SARS-CoV-2 spike (anti-S) and anti-nucleocapsid (anti-NP) and concomitantly assessed virus neutralization using a pseudovirus neutralization assay. Patients received either the Pfizer/BioNTech BNT162b2, or the Oxford/AstraZeneca ChAdOx1 vaccine. RESULTS: All 152 patients enrolled had a prior diagnosis of cancer; colorectal (n = 80, 52.6%), oesophagogastric (n = 38, 25.0%), and hepato pancreatic biliary (n = 22, 12.5%). Nearly all were receiving systemic anti-cancer therapy (99.3%). Of the 51 patients who did not receive a vaccination prior to, or during the study, 5 patients had detectable anti-NP antibodies. Ninety-nine patients received at least one dose of vaccine prior to, or during the study. Within 19 days following the first dose of vaccine, 30.0% had anti-S detected in serum which increased to 70.2% at days 20-39. In the 19 days following a second dose, anti-S positivity was 84.2% (32/38). However, pseudovirus neutralization titers (pVNT80) decreased from days 20 to 39. CONCLUSION: Despite the immunosuppressive effects of chemotherapy, 2 doses of SARS-CoV-2 vaccines are able to elicit a protective immune response in patients' ongoing treatment for gastrointestinal cancers. Decreases in pseudoviral neutralization were observed after 20-39 days, re-affirming the current recommendation for vaccine booster doses. CLINICAL TRIAL REGISTRATION NUMBER: NCT04427280
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