346 research outputs found

    End of OSLER test sessions in Parkinson’s disease do not correspond to true sleep onset: results from an exploratory study

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    Copyright © 2015 Neutel, Peralta, Pires, Bentes and Ferreira. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.The aim of the present study was to evaluate the correlation between the end of an Oxford sleep resistance (OSLER) test session and a neurophysiological marker of sleep onset in Parkinson's disease (PD) patients. Single center study was conducted in PD patients with excessive daytime sleepiness [Epworth sleepiness scale (ESS) >9]. The OSLER test was conducted with a concomitant electroencephalography (EEG), electromyography (mentalis), right and left electroculogram, and video monitoring. Neurophysiological (NP) sleep onset was defined according to AASM criteria (2005). Five PD patients with mean ESS of 14 (10-16) were included. OSLER test duration was shorter than 40 min in all patients (mean duration 20 min and 39 s). No patient fulfilled neurophysiological criteria to sleep onset at the time of OSLER test termination. In 13 OSLER sessions that ended before 40 min, eight had microsleeps in the last 30 s before the end of the test. NP monitoring showed signs of sleepiness in all patients. In PD patients, the early termination of an OSLER test session may not correspond to NP criteria of sleep onset. However, in all PD patients with abnormal OSLER results, there were EEG signs of sleepiness, which do not exclude the potential utility of OSLER test to evaluate the risk of falling asleep.info:eu-repo/semantics/publishedVersio

    End of OSLER test sessions in Parkinson’s disease do not correspond to true sleep onset: results from an exploratory study

    Get PDF
    Copyright © 2015 Neutel, Peralta, Pires, Bentes and Ferreira. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.The aim of the present study was to evaluate the correlation between the end of an Oxford sleep resistance (OSLER) test session and a neurophysiological marker of sleep onset in Parkinson's disease (PD) patients. Single center study was conducted in PD patients with excessive daytime sleepiness [Epworth sleepiness scale (ESS) >9]. The OSLER test was conducted with a concomitant electroencephalography (EEG), electromyography (mentalis), right and left electroculogram, and video monitoring. Neurophysiological (NP) sleep onset was defined according to AASM criteria (2005). Five PD patients with mean ESS of 14 (10-16) were included. OSLER test duration was shorter than 40 min in all patients (mean duration 20 min and 39 s). No patient fulfilled neurophysiological criteria to sleep onset at the time of OSLER test termination. In 13 OSLER sessions that ended before 40 min, eight had microsleeps in the last 30 s before the end of the test. NP monitoring showed signs of sleepiness in all patients. In PD patients, the early termination of an OSLER test session may not correspond to NP criteria of sleep onset. However, in all PD patients with abnormal OSLER results, there were EEG signs of sleepiness, which do not exclude the potential utility of OSLER test to evaluate the risk of falling asleep.info:eu-repo/semantics/publishedVersio

    Towards a new philosophy of engineering: structuring the complex problems from the sustainability discourse

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    This dissertation considers three broad issues which emerge from the sustainability discourse. First is the nature of the discourse itself, particularly the underlying philosophical positions which are represented. Second, is the nature of the highly complex types of problem which the discourse exposes. And third is whether the engineering profession, as it is practised currently, is adequate to deal with such problems. The sustainability discourse exposes two distinct, fundamentally irreconcilable philosophical positions. The first, “sustainable development”, considers humanity to be privileged in relation to all other species and ecosystems. It is only incumbent upon us to look after the environment to the extent to which it is in our interests to do so. The second, “sustainability”, sees humanity as having no special moral privilege and recognises the moral status of other species, ecosystems, and even wilderness areas. Thus, sustainability imposes upon us a moral obligation to take their status into account and not to degrade or to destroy them. These two conflicting positions give rise to extremely complex problems. An innovative taxonomy of problem complexity has been developed which identifies three broad categories of problem. Of particular interest in this dissertation is the most complex of these, referred to here as the Type 3 problem. The Type 3 problem recognises the systemic complexity of the problem situation but also includes differences of the domain of interests as a fundamental, constituent part of the problem itself. Hence, established systems analysis techniques and reductionist approaches do not work. The domain of interests will typically have disparate ideas and positions, which may be entirely irreconcilable. The dissertation explores the development of philosophy of science, particularly in the last 70 years. It is noted that, unlike the philosophy of science, the philosophy of engineering has not been influenced by developments of critical theory, cultural theory, and postmodernism, which have had significant impact in late 20th-century Western society. This is seen as a constraint on the practice of engineering. Thus, a set of philosophical principles for sustainable engineering practice is developed. Such a change in the philosophy underlying the practice of engineering is seen as necessary if engineers are to engage with and contribute to the resolution of Type 3 problems. Two particular challenges must be overcome, if Type 3 problems are to be satisfactorily resolved. First, issues of belief, values, and morals are central to this problem type and must be included in problem consideration. And second, the problem situation is usually so complex that it challenges the capacity of human cognition to deal with it. Consequently, extensive consideration is given to cognitive and behavioural psychology, in particular to choice, judgement and decision-making in uncertainty. A novel problem-structuring approach is developed on three levels. A set philosophical foundation is established; a theoretical framework, based on general systems theory and established behavioural and cognitive psychological theory, is devised; and a set of tools is proposed to model Type 3 complex problems as a dynamic systems. The approach is different to other systems approaches, in that it enables qualitative exploration of the system to plausible, hypothetical disturbances. The problem-structuring approach is applied in a case study, which relates to the development of a water subsystem for a major metropolis (Sydney, Australia). The technique is also used to critique existing infrastructure planning processes and to propose an alternative approach

    ATENA–A Novel Rapidly Manufactured Medical Invasive Ventilator Designed as a Response to the COVID-19 Pandemic: Testing Protocol, Safety, and Performance Validation

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    Background: The urgent need for mechanical ventilators to support respiratory insufficiency due to SARS-CoV-2 led to a worldwide effort to develop low-cost, easily assembled, and locally manufactured ventilators. The ATENA ventilator project was developed in a community-based approach targeting the development, prototyping, testing, and decentralized manufacturing of a new mechanical ventilator. Objective: This article aims to demonstrate ATENA's adequate performance and safety for clinical use. Material: ATENA is a low-cost ventilator that can be rapidly manufactured, easily assembled, and locally produced anywhere in the world. It was developed following the guidelines and requirements provided by European and International Regulatory Authorities (MHRA, ISO 86201) and National Authorities (INFARMED). The device was thoroughly tested using laboratory lung simulators and animal models. Results: The device meets all the regulatory requirements for pandemic ventilators. Additionally, the pre-clinical experiences demonstrated security and adequate ventilation and oxygenation, in vivo. Conclusion: The ATENA ventilator had a good performance in required tests in laboratory scenarios and pre-clinical studies. In a pandemic context, ATENA is perfectly suited for safely treating patients in need of mechanical ventilation.Financial support and sponsorship by CEiiA, INOV4COVID program, donations from scientific patronage, and commercial sales

    Changes in and predictors of length of stay in hospital after surgery for breast cancer between 1997/98 and 2004/05 in two regions of England: a population-based

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    BACKGROUND Decreases in length of stay (LOS) in hospital after breast cancer surgery can be partly attributed to the change to less radical surgery, but many other factors are operating at the patient, surgeon and hospital levels. This study aimed to describe the changes in and predictors of length of stay (LOS) in hospital after surgery for breast cancer between 1997/98 and 2004/05 in two regions of England. METHODS Cases of female invasive breast cancer diagnosed in two English cancer registry regions were linked to Hospital Episode Statistics data for the period 1st April 1997 to 31st March 2005. A subset of records where women underwent mastectomy or breast conserving surgery (BCS) was extracted (n = 44,877). Variations in LOS over the study period were investigated. A multilevel model with patients clustered within surgical teams and NHS Trusts was used to examine associations between LOS and a range of factors. RESULTS Over the study period the proportion of women having a mastectomy reduced from 58% to 52%. The proportion varied from 14% to 80% according to NHS Trust. LOS decreased by 21% from 1997/98 to 2004/05 (LOSratio = 0.79, 95%CI 0.77-0.80). BCS was associated with 33% shorter hospital stays compared to mastectomy (LOSratio = 0.67, 95%CI 0.66-0.68). Older age, advanced disease, presence of comorbidities, lymph node excision and reconstructive surgery were associated with increased LOS. Significant variation remained amongst Trusts and surgical teams. CONCLUSION The number of days spent in hospital after breast cancer surgery has continued to decline for several decades. The change from mastectomy to BCS accounts for only 9% of the overall decrease in LOS. Other explanations include the adoption of new techniques and practices, such as sentinel lymph node biopsy and early discharge. This study has identified wide variation in practice with substantial cost implications for the NHS. Further work is required to explain this variation

    Sheldon Spectrum and the Plankton Paradox: Two Sides of the Same Coin : A trait-based plankton size-spectrum model

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    The Sheldon spectrum describes a remarkable regularity in aquatic ecosystems: the biomass density as a function of logarithmic body mass is approximately constant over many orders of magnitude. While size-spectrum models have explained this phenomenon for assemblages of multicellular organisms, this paper introduces a species-resolved size-spectrum model to explain the phenomenon in unicellular plankton. A Sheldon spectrum spanning the cell-size range of unicellular plankton necessarily consists of a large number of coexisting species covering a wide range of characteristic sizes. The coexistence of many phytoplankton species feeding on a small number of resources is known as the Paradox of the Plankton. Our model resolves the paradox by showing that coexistence is facilitated by the allometric scaling of four physiological rates. Two of the allometries have empirical support, the remaining two emerge from predator-prey interactions exactly when the abundances follow a Sheldon spectrum. Our plankton model is a scale-invariant trait-based size-spectrum model: it describes the abundance of phyto- and zooplankton cells as a function of both size and species trait (the maximal size before cell division). It incorporates growth due to resource consumption and predation on smaller cells, death due to predation, and a flexible cell division process. We give analytic solutions at steady state for both the within-species size distributions and the relative abundances across species

    Prostate cancer, treatment modalities and complications: an evaluation of the scientific literature

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    Prostate (PR) cancer (CA) is one of the most common malignant neoplasms in men all over the world. In general, if prostate cancer (PC) is detected early, treatment usually involves either surgical removal of the prostate or radiotherapy (RT). Hormone Therapy (HT) or chemotherapy (CH) is the preferred treatment for more advanced cases of PC or if CA spreads beyond the PT. A number of complications, such as urinary incontinence (IU) or erectile dysfunction (ED), can be associated with some modalities of treatment of the PC. The aim of this work is to evaluate, in PubMed, the number of publications related with prostate cancer and the main modalities of treatment, as well as some clinical complications. The searches were performed in PubMed (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) in the period 1950 to 2008 using the words: (i) CA, (ii) CA and PR or penis or testis, (iii) CA and PR and RT, CA and PR and surgery (SU), CA and PR and CH and, CA and PR and HT and (iv) CA and PR and RT and IU or ED, CA and PR and SU and IU or ED, CA and PR and CH and IU or ED and, CA and PR and HT and CH and IU or ED, and (V) PC and the same modalities of treatment. The data was obtained on July 20th, 2008. PC, as expected has been cited extensively and surgery has been identified as the most widely referenced modality of treatment. Furthermore, urinary incontinence and erectile dysfunction are important complications that have attracted significant scientific interest. In conclusion, these findings have shown the relevance of the PubMed to analyze quantitatively the publications in cancer and this information could be worthwhile in aiding the comprehension of some clinical aspects related with PC, as well as the development of preventative actions. The analysis of the scientific interest, considering the number of publications in the PubMed, reveals research trends in the field and demonstrates the importance of the surgical procedures in the treatment of the prostate cancer. Moreover, this finding is relevant due to the fact that surgery is the treatment of choice when early detection of PC is achieved. However, it is important to consider clinical complications related to such procedures, such as urinary incontinence and erectile dysfunctions that can reduce the quality of life of the patient

    Inherent directionality explains the lack of feedback loops in empirical networks

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    We explore the hypothesis that the relative abundance of feedback loops in many empirical complex networks is severely reduced owing to the presence of an inherent global directionality. Aimed at quantifying this idea, we propose a simple probabilistic model in which a free parameter γ controls the degree of inherent directionality. Upon strengthening such directionality, the model predicts a drastic reduction in the fraction of loops which are also feedback loops. To test this prediction, we extensively enumerated loops and feedback loops in many empirical biological, ecological and socio-technological directed networks. We show that, in almost all cases, empirical networks have a much smaller fraction of feedback loops than network randomizations. Quite remarkably, this empirical finding is quantitatively reproduced, for all loop lengths, by our model by fitting its only parameter γ. Moreover, the fitted value of γ correlates quite well with another direct measurement of network directionality, performed by means of a novel algorithm. We conclude that the existence of an inherent network directionality provides a parsimonious quantitative explanation for the observed lack of feedback loops in empirical networks
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