90 research outputs found

    H∞ filtering for uncertain stochastic time-delay systems with sector-bounded nonlinearities

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    This is the post print version of the article. The official published version can be obtained from the link - Copyright 2008 Elsevier Ltd.In this paper, we deal with the robust H∞ filtering problem for a class of uncertain nonlinear time-delay stochastic systems. The system under consideration contains parameter uncertainties, Itô-type stochastic disturbances, time-varying delays, as well as sector-bounded nonlinearities. We aim at designing a full-order filter such that, for all admissible uncertainties, nonlinearities and time delays, the dynamics of the filtering error is guaranteed to be robustly asymptotically stable in the mean square, while achieving the prescribed H∞ disturbance rejection attenuation level. By using the Lyapunov stability theory and Itô’s differential rule, sufficient conditions are first established to ensure the existence of the desired filters, which are expressed in the form of a linear matrix inequality (LMI). Then, the explicit expression of the desired filter gains is also characterized. Finally, a numerical example is exploited to show the usefulness of the results derived.This paper was not presented at any IFAC meeting. This paper was recommended for publication in revised form by Associate Editor Tongwen Chen under the direction of Editor Ian Petersen. This work was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) of the UK under Grant GR/S27658/01, an International Joint Project sponsored by the Royal Society of the UK and the NSFC of China, the Alexander von Humboldt Foundation of Germany, the Natural Science Foundation of Jiangsu Province of China under Grant BK2007075, the Natural Science Foundation of Jiangsu Education Committee of China under Grant 06KJD110206, the National Natural Science Foundation of China under Grants 60774073 and 10671172, and the Scientific Innovation Fund of Yangzhou University of China under Grant 2006CXJ002

    MARCKS phosphorylation is modulated by a peptide mimetic of MARCKS effector domain leading to increased radiation sensitivity in lung cancer cell lines

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    Lung cancer is the leading cause of cancer-associated mortality in the United States. Kinase hyperactivation is a known mechanism of tumorigenesis. The phosphorylation status of the plasma membrane-associated protein myristoylated alanine rich C-kinase substrate (MARCKS) effector domain (ED) was previously established as being important in the sensitivity of lung cancer to radiation. Specifically, when MARCKS ED was in a non-phosphorylated state, lung cancer cells were more susceptible to ionizing radiation and experienced prolonged double-strand DNA breaks. Additional studies demonstrated that the phosphorylation status of MARCKS ED is important for gene expression and in vivo tumor growth. The present study used a peptide mimetic of MARCKS ED as a therapeutic intervention to modulate MARCKS phosphorylation. Culturing A549, H1792 and H1975 lung cancer cell lines with the MARCKS ED peptide led to reduced levels of phosphorylated MARCKS and phosphorylated Akt serine/threonine kinase 1. Further investigation demonstrated that the peptide therapy was able to reduce lung cancer cell proliferation and increase radiation sensitivity. In addition, the MARCKS peptide therapy was able to prolong double-strand DNA breaks following ionizing radiation exposure. The results of the present study demonstrate that a peptide mimetic of MARCKS ED is able to modulate MARCKS phosphorylation, leading to an increase in sensitivity to radiation. Keywords: lung cancer, myristoylated alanine rich C-kinase substrate, radiation sensitivity, effector domain, peptide mimeti

    Using historical documentary methods to explore the history of occupational therapy

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    peer-reviewed.Introduction: Historical research can benefit health professions by providing a basis for understanding how current beliefs and practices developed over time. From an occupational therapy perspective, a need for deeper critical understandings of the profession has been identified; historical research can facilitate this process. Documentary research is a significant methodology in historical inquiry, but there is a dearth of guidance for occupational therapists wishing to employ this method. Method: A conceptual literature review was conducted to describe how to use documentary sources to understand the development of the profession, drawing on literature from the disciplines of history and occupational therapy. Results: The stages of historical documentary research are described: choosing a topic, sourcing and selecting evidence, and managing sources. How to consider the authenticity, credibility and representativeness of historical material is discussed. Various means to determine the meaning of historical evidence are considered, with chronological, thematic and theoretical approaches proposed. Conclusion: Methodological transparency is central to the process of historical documentary research. To enhance understanding of the quality of historical source material, adoption of the guidelines outlined is recommended. Adopting a clearly defined questioning perspective promotes more substantial conclusions and professional understandingspeer-reviewe

    The United Kingdom and British Empire: A Figurational Approach

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    Drawing upon the work of Norbert Elias and the process [figurational] sociology perspective, this article examines how state formation processes are related to, and, affected by, expanding and declining chains of international interdependence. In contrast to civic and ethnic conceptions, this approach focuses on the emergence of the nation/nation-state as grounded in broader processes of historical and social development. In doing so, state formation processes within the United Kingdom are related to the expansion and decline of the British Empire. That is, by focusing on the functional dynamics that are embedded in collective groups, one is able to consider how the UK’s ‘state’ and ‘imperial’ figurations were interdependently related to changes in both the UK and the former British Empire. Consequently, by locating contemporary UK relations in the historical context of former imperial relationships, nationalism studies can go ‘beyond’ the nation/nation-state in order to include broader processes of imperial expansion and decline. Here, the relationship between empire and nationalism can offer a valuable insight into contemporary political movements, especially within former imperial groups

    An engineering perspective of vacuum assisted delivery devices in obstetrics: A review

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    Complications during childbirth result in the need for clinicians to use ‘assisted delivery’ in over 12% of cases (UK). After more than 50 years in clinical practice, vacuum assisted delivery (VAD) devices remain a mainstay in physically assisting child delivery; sometimes preferred over forceps due to their ease of use and reduced maternal morbidity. Despite their popularity and enduring track-record, VAD devices have shown little evidence of innovation or design change since their inception. In addition, evidence on the safety and functionality of VAD devices remains limited but does present opportunities for improvements to reduce adverse clinical outcomes. Consequently in this review we examine the literature and patent landscape surrounding VAD biomechanics, design evolution and performance from an engineering perspective, aiming to collate the limited but valuable information from a disparate field and provide a series of recommendations to inform future research into improved, safer, VAD systems

    Gastrointestinal symptoms, inflammation and hypoalbuminemia in chronic kidney disease patients: a cross-sectional study

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    BACKGROUND: Few studies have focused on investigating hypoalbuminemia in patients during earlier stages of chronic kidney disease (CKD). In particular, little is known about the role of gastrointestinal (GI) symptoms. Our goal in this paper is to study how GI symptoms relate to serum albumin levels in CKD, especially in the context of and compared with inflammation. METHODS: We performed a cross-sectional study of 3599 patients with chronic kidney disease enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study. All subjects were asked to complete the Modification of Diet in Renal Disease (MDRD) study patient symptom form. Our main predictor is GI symptom score. Serum level of C-reactive protein (CRP) was measured as well. Main outcome measures are serum albumin levels and prevalence of hypoalbuminemia. RESULTS: Of the participants assessed, mean serum albumin was 3.95 ± 0.46 g/dL; 12.7 % had hypoalbuminemia. Patients with lower estimated glomerular filtration rate (eGFR) were likely to have more GI symptoms (apparent at an eGFR <45 ml/min/1.73 m(2)). Patients with worse GI symptoms had lower dietary protein intake. GI symptoms, like inflammation, were risk factors for lower serum albumin levels. However, adding GI symptom score or CRP into the multivariable regression analysis, did not attenuate the association between lower eGFR and lower albumin or hypoalbuminemia. CONCLUSIONS: Increased prevalence of GI symptoms become apparent among CKD patients at relatively high eGFR levels (45 ml/min/1.73 m(2)), long before ESRD. Patients with more severe GI symptoms scores are more likely to have hypoalbuminemia. But our data do not support GI symptoms/decreased protein intake or inflammation as being the main determinants of serum albumin level in CKD patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12882-015-0209-z) contains supplementary material, which is available to authorized users

    Politics, 1641-1660

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    Travel Writing and Rivers

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    Curriculum Evaluation Using the IFNA Generalist Competencies for Family Nursing Practice

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    Using a blueprint based on program evaluation theory, the program was assessed based on the key concepts identified in the IFNA Position Statement on Generalist Competencies for Family Nursing Practice. A survey instrument based on the five IFNA competencies was created and applied to each course in the program. In addition, lead faculty were surveyed. The program’s philosophy, course syllabi, readings, clinical evaluation instruments and other assignments were examined for the key concepts. Implications for curriculum/program revision, challenges and further nursing research will be presented

    Curriculum Evaluation Using the IFNA Generalist Competencies for Family Nursing Practice

    No full text
    Using a blueprint based on program evaluation theory, the program was assessed based on the key concepts identified in the IFNA Position Statement on Generalist Competencies for Family Nursing Practice. A survey instrument based on the five IFNA competencies was created and applied to each course in the program. In addition, lead faculty were surveyed. The program’s philosophy, course syllabi, readings, clinical evaluation instruments and other assignments were examined for the key concepts. Implications for curriculum/program revision, challenges and further nursing research will be presented
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