4,026 research outputs found

    Towards automatic classification within the ChEBI ontology

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    *Background*
Appearing in a wide variety of contexts, biochemical 'small molecules' are a core element of biomedical data. Chemical ontologies, which provide stable identifiers and a shared vocabulary for use in referring to such biochemical small molecules, are crucial to enable the interoperation of such data. One such chemical ontology is ChEBI (Chemical Entities of Biological Interest), a candidate member ontology of the OBO Foundry. ChEBI is a publicly available, manually annotated database of chemical entities and contains around 18000 annotated entities as of the last release (May 2009). ChEBI provides stable unique identifiers for chemical entities; a controlled vocabulary in the form of recommended names (which are unique and unambiguous), common synonyms, and systematic chemical names; cross-references to other databases; and a structural and role-based classification within the ontology. ChEBI is widely used for annotation of chemicals within biological databases, text-mining, and data integration. ChEBI can be accessed online at "http://www.ebi.ac.uk/chebi/":http://www.ebi.ac.uk/chebi/ and the full dataset is available for download in various formats including SDF and OBO.

*Automated Classification*
The selection of chemical entities for inclusion in the ChEBI database is user-driven. As the use of ChEBI has grown, so too has the backlog of user-requested entries. Inevitably, the annotation backlog creates a bottleneck, and to speed up the annotation process, ChEBI has recently released a submission tool which allows community submissions of chemical entities, groups, and classes. However, classification of chemical entities within the ontology is a difficult and niche activity, and it is unlikely that the community as a whole will be able or willing to correctly and consistently classify each submitted entity, creating required classes where they are missing. As a result, it is likely that while the size of the database grows, the ontological classification will become less sophisticated, unless the classification of new entities is assisted computationally. In addition, the ChEBI database is expecting substantial size growth in the next year, so automatic classification, which has up till now not been possible, is urgently required. Automatic classification would also enable the ChEBI ontology classes to be applied to other compound databases such as PubChem. 

*Description Logic Reasoning*
Description logic based reasoning technology is a prime candidate for development of such an automatic classification system as it allows the rules of the classification system to be encoded within the knowledgebase. Already at 18000 entities, ChEBI is a fair size for a real-world application of description logic reasoning technology, and as the ontology is enhanced with a richer density of asserted relationships, the classification will become more complex and challenging. We have successfully tested a description logic-based classification of chemical entities based on specified structural properties using the hypertableaux-based HermiT reasoner, and found it to be sufficiently efficient to be feasible for use in a production environment on a database of the size that ChEBI is now. However, much work still remains to enrich the ChEBI knowledgebase itself with the properties needed to provide the formal class definitions for use in the automated classification, and to assess the efficiency of the available description logic reasoning technology on a database the size of ChEBI's forecast future growth.

*Acknowledgements*
ChEBI is funded by the European Commission under SLING, grant agreement number 226073 (Integrating Activity) within Research Infrastructures of the FP7 Capacities Specific Programme, and by the BBSRC, grant agreement number BB/G022747/1 within the “Bioinformatics and biological resources” fund

    Observations Outside the Light-Cone: Algorithms for Non-Equilibrium and Thermal States

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    We apply algorithms based on Lieb-Robinson bounds to simulate time-dependent and thermal quantities in quantum systems. For time-dependent systems, we modify a previous mapping to quantum circuits to significantly reduce the computer resources required. This modification is based on a principle of "observing" the system outside the light-cone. We apply this method to study spin relaxation in systems started out of equilibrium with initial conditions that give rise to very rapid entanglement growth. We also show that it is possible to approximate time evolution under a local Hamiltonian by a quantum circuit whose light-cone naturally matches the Lieb-Robinson velocity. Asymptotically, these modified methods allow a doubling of the system size that one can obtain compared to direct simulation. We then consider a different problem of thermal properties of disordered spin chains and use quantum belief propagation to average over different configurations. We test this algorithm on one dimensional systems with mixed ferromagnetic and anti-ferromagnetic bonds, where we can compare to quantum Monte Carlo, and then we apply it to the study of disordered, frustrated spin systems.Comment: 19 pages, 12 figure

    Tobacco Harm Reduction and Nicotine Containing Products: Research Priorities and Policy Directions

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    Developments in tobacco harm reduction (HR) and the proliferation of nicotine containing products (NCPs) have important implications for tobaco control (TC). This report sets out a research agenda which will help map and examine these implications

    Britain's efforts to reduce smoking are becoming a cash cow for big tobacco

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    First paragraph: It all began so well. A decade ago a heartfelt concern about the addictiveness of nicotine, and the enormous difficulties this presented for would-be quitters, led to an unprecedented investment in intensive smoking cessation services. Beyond Smoking Kills proudly proclaimed year-on-year increases in funding for stop-smoking services and the establishment of centres throughout the country. Access this article on The Conversation website: https://theconversation.com/britains-efforts-to-reduce-smoking-are-becoming-a-cash-cow-for-big-tobacco-2533

    The marketing of e-cigarettes: a quick snapshot

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    First paragraph: The electronic cigarette (e-cigarette) was launched as a new consumer product in the UK eight years ago.ii Sales now exceed half a million per year and analysts predict the e-cigarette industry, which is worth £150 million in the UK,iii will continue to grow as usage among smokers has more than doubled in two years.iv At present, they are not classed as tobacco products or medicines in the UK and are therefore only regulated under Trading Standards legislation. The situation may change if the health regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), enforces tighter regulations - a decision on whether e-cigarettes require marketing authorisation to prove safety and efficacy is imminent

    Testing three hypotheses about effects of sensitive-insensitive parenting on telomeres.

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    Telomeres are the protective DNA-protein sequences appearing at the ends of chromosomes; they shorten with each cell division and are considered a biomarker of aging. Shorter telomere length and greater erosion have been associated with compromised physical and mental health and are hypothesized to be affected by early life stress. In the latter case, most work has relied on retrospective measures of early life stressors. The Dutch research (n = 193) presented herein tested 3 hypotheses prospectively regarding effects of sensitive-insensitive parenting during the first 2.5 years on telomere length at age 6, when first measured, and change over the following 4 years. It was predicted that (1) less sensitive parenting would predict shorter telomeres and greater erosion and that such effects would be most pronounced in children (2) exposed to prenatal stress and/or (3) who were highly negatively emotional as infants. Results revealed, only, that prenatal stress amplified parenting effects on telomere change-in a differential-susceptibility-related manner: Prenatally stressed children displayed more erosion when they experienced insensitive parenting and less erosion when they experienced sensitive parenting. Mechanisms that might initiate greater postnatal plasticity as a result of prenatal stress are highlighted and future work outlined. (PsycINFO Database Record (c) 2020 APA, all rights reserved)

    Promotion of electronic cigarettes: tobacco marketing reinvented?

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    Electronic cigarettes are not subject to the same marketing controls as tobacco products. Marisa de Andrade, Gerard Hastings, and Kathryn Angus argue that their advertising is likely to appeal to young people and undermine tobacco control policy

    Comparison Of Abdominal Compression Devices In Persons With Abdominal Paralysis Due To Spinal Cord Injury

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    Comparison of abdominal compression devices in persons with abdominal paralysis due to spinal cord injury. Michaela de Groot, MA, SPT; Jennifer Swartz, MA, SPT; Jennifer Hastings PT, PhD, NCS University of Puget Sound, Tacoma WA Objective: In the United States the incidence of spinal cord injury (SCI) is approximately 17,000 new cases a year and there are estimated to be 282,000 persons living with SCI. Approximately 80% of those injured sustain neurologic lesions that impair the function of the abdominal musculature. In the non-disabled population it is well understood that the strength of the abdominal wall is key to prevention of musculoskeletal pain and improving postural control. The abdominal wall functions to maintain intra-abdominal cavity pressure which in a healthy system works in coordination with intra-thoracic cavity pressure. Paralysis of the abdominal musculature impairs the function of the diaphragm. Use of an abdominal binder is a common intervention following acute SCI.However, the long term daily use of abdominal binders is not common among individuals living with SCI. The purpose of this study is to compare the effectiveness and usability of alternative commercial abdominal compression garments with the usual medical device. Design/Methods: This study follows a single subject design with 5 participants. Inclusion: SCI T6 or above, currently using abdominal binder when seated in the wheelchair, able to don the binder independently or with caregiver assistance. Exclusion: Unable to speak English and communicate either written or electronically, or current skin breakdown. Data was collected over 3 periods of 1 week at a time; participants wore the compression garment for 5 days followed by a rest period of 2 days. In week 1, the participant wore their current abdominal binder. In weeks 2 and 3, an alternative compression device was worn. The alternatives were a compressive tank top and a compressive unisuit (shorts and tank). Physiological measurements and photographs were taken with the current binder, then after a 5 minute acclimation period each without any binder and then the alternative garment. Outcome measures: blood pressure, blood oxygen saturation, forced exhalation volume in 1 second, and heart rate. A daily log was completed twice daily for 5 days per garment with questions asking about participants’ experience. Results: The use of a personal binder resulted in significant increases in systolic blood pressure (SBP) and forced expiratory volume in 1 second (FEV1). The other parameters were not significantly different with or without the personal binder. There was no difference in SBP between the test garments and the personal binders, but the test garments’ support of FEV1 was significantly less. Graphic analysis of experiential trends will be presented. Conclusion: Abdominal compression improves respiratory function and supports BP. The alternative devices provided similar BP support, but less respiratory support. Alternative devices required caregiver assistance. Lack of full UE ROM made the tank option unfeasible. The unisuit offended sensibilities and therefore is not an acceptable device. Support: This study received support from the University of Puget Sound

    Tobacco harm reduction: the devil is in the deployment

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    First paragraph: The idea of tobacco harm reduction -- that smokers who cannot wean themselves off nicotine should be encouraged to adopt less harmful ways of consuming it -- has much to recommend it. It avoids the trap of making the excellent (complete cessation) the enemy of the good (reduced harm) and provides a way forward where otherwise there is only a cruel impasse. It also provides a clear focus on disease and premature death -- rather than tobacco addiction or corporate power -- and this enemy, like so many medical problems before it, will be defeated with rigorous evidence, effective medicines, and skilled treatment
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