168 research outputs found

    Fast relational learning using bottom clause propositionalization with artificial neural networks

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    Relational learning can be described as the task of learning first-order logic rules from examples. It has enabled a number of new machine learning applications, e.g. graph mining and link analysis. Inductive Logic Programming (ILP) performs relational learning either directly by manipulating first-order rules or through propositionalization, which translates the relational task into an attribute-value learning task by representing subsets of relations as features. In this paper, we introduce a fast method and system for relational learning based on a novel propositionalization called Bottom Clause Propositionalization (BCP). Bottom clauses are boundaries in the hypothesis search space used by ILP systems Progol and Aleph. Bottom clauses carry semantic meaning and can be mapped directly onto numerical vectors, simplifying the feature extraction process. We have integrated BCP with a well-known neural-symbolic system, C-IL2P, to perform learning from numerical vectors. C-IL2P uses background knowledge in the form of propositional logic programs to build a neural network. The integrated system, which we call CILP++, handles first-order logic knowledge and is available for download from Sourceforge. We have evaluated CILP++ on seven ILP datasets, comparing results with Aleph and a well-known propositionalization method, RSD. The results show that CILP++ can achieve accuracy comparable to Aleph, while being generally faster, BCP achieved statistically significant improvement in accuracy in comparison with RSD when running with a neural network, but BCP and RSD perform similarly when running with C4.5. We have also extended CILP++ to include a statistical feature selection method, mRMR, with preliminary results indicating that a reduction of more than 90 % of features can be achieved with a small loss of accuracy

    Prenylated flavonoids as evolutionary indicators in the genus Dahlstedtia.

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    Abstract: Three chalcones, two beta-hydroxychalcones, four flavanones, six flavones, four flavonols, one rotenoid and one pterocarpan were isolated from the roots of Dahlstedtia pinnata and D. pentaphylla. With the exception of the pterocarpan, all the compounds exhibit prenylation in the A ring, a characteristic of flavonoids produced by species of the Tephrosieae. Of the 21 flavonoids identified, five (2 flavanones and 3 flavones) are new as naturally occurring compounds. A neat distinction in the biosynthetic capability of the two species, leading to the production of flavanones and flavonols in D. pentaphylla, but not in D. pinnata, is observed. In this latter species, biosynthesis is totally oriented toward dehydrogenation, producing flavones. By both criteria-higher oxidation state and suppression of enzyme systems-D. pinnata is the more advanced species

    Efeito alelopático do extrato bruto de Brachiaria decumbens na germinação e no vigor de sementes e de plântulas de Brachiaria brizantha.

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    Objetivou-se identificar os possíveis efeitos alelopáticos produzidos pelo extrato bruto de um acesso da coleção de Brachiaria spp da Embrapa Gado de Corte, denominado Brachiaria decumbens BRA001996 na germinação, no vigor de sementes e no vigor de plântulas de três cultivares de B. brizantha (cvs. Marandu, BRS Piatã e Xaraés). As sementes das cultivares foram semeadas em papel germitest, colocadas em gerbox e incubadas em câmara climática com fotoperíodo controlado. Utilizaram-se quatro repetições de 100 sementes para os testes de germinação e vigor e 25 sementes para o teste de vigor de plântulas. O extrato bruto foi obtido das folhas da gramínea, por meio de técnica laboratorial utilizada para detecção e quantificação de avaliação de saponinas esteroidais. Foram avaliadas duas testemunhas: uma somente com água destilada e outra com água destilada e acrescida de 1% de DMSO e quatro concentrações: 1,85g/mL (10%); 3,7g/mL (20%); 5,55g/mL (30%) e 9,25 mg/mL (50%), totalizando seis tratamentos. Observou-se efeito ?dose-resposta? inibitório significativo (P<0,05) em todos as variáveis avaliadas, nas sementes das três cultivares estudadas. Sabendo-se que os compostos hormonais agem estimulando ou inibindo o metabolismo celular, sugere-se que os efeitos alelopáticos observados no presente trabalho possam estar relacionados ao efeito direto das saponinas esteroidais nas células das sementes e das plântulas das B. brizantha avaliadas. Conclui-se que o extrato bruto de Brachiaria decumbens BRA001996 reduz o vigor e a germinação das sementes, bem como o vigor das plântulas de Brachiaria brizantha, cultivares Xaraés, Piatã e Marandu.bitstream/item/68749/1/DOC188.pd

    Specialist Peri-Operative Allergy Clinic Services in the UK 2016: Results from the Royal College of Anaesthetists Sixth National Audit Project (NAP6)

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    BACKGROUND: Guidelines for investigation of perioperative drug allergy exist, but the quality of services is unknown. Specialist perioperative anaphylaxis services were surveyed through the Royal College of Anaesthetists 6(th) National Audit Project. OBJECTIVES: We compare self-declared UK practice in specialist perioperative allergy services with national recommendations. METHODS: A SurveyMonkey(™) questionnaire was distributed to providers of allergy services in the UK. Responses were assessed for adherence to the best practice recommendations of the British Society for Allergy and Clinical Immunology, the Association of Anaesthetists of Great Britain and Ireland and the National Institute for Health and Care Excellence (NICE) Guidance on Drug Allergy - CG183. RESULTS: Over 1200 patients were evaluated in 44 centres annually. Variation in workload, waiting times, access, staffing and diagnostic approach was noted. Paediatric centres had the longest routine waiting times (most wait >13 weeks) in contrast to adult centres (most wait <12 weeks). Service leads are allergists/immunologists (91%) or anaesthetists (7%). Potentially important differences were seen in: testing repertoire [10/44 (23%) lacked BSACI compliant NMBA panels and 17/44 (39%) lacked a NAP6-defined extended panel; many failed to screen all cases for chlorhexidine 19/44 (43%) or latex 21/44 (48%)], staffing [only 26/44 (59%) had specialist nurses and 18/44 (41%) an anaesthetist], and provision of information [18/44 (41%) gave immediate information in clinic, and 5/44 (11%) on support groups]. Most centres were able to provide diagnostic challenges to antibiotics [40/44 (91%]) and local anaesthetics [41/44 (93%)]. CONCLUSIONS AND CLINICAL RELEVANCE: Diagnostic testing is not harmonised, with marked variability in the NMBA panels used to identify safe alternatives. Chlorhexidine and latex are not part of routine testing in many centres. Poor access to services and patient information provision require attention. Harmonisation of diagnostic approach is desirable, particularly with regard to a minimum NMBA panel for identification of safe alternatives. This article is protected by copyright. All rights reserved

    Positive correlation between fluoride release and acid erosion of restorative glass-ionomer cements.

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    OBJECTIVE: The aim of this study was to determine whether there is a correlation between acid erosion and fluoride release of conventional glass ionomer cements. METHODS: Ten specimens for each material were prepared for fluoride release tests and five for acid erosion tests separately. After placed in pH cycling solution, concentration of fluoride was measured by a fluoride-ion selective electrode each day for 15 days. For the acid erosion test, specimens were immersed in a lactic acid solution and their depth measured with a spring-loaded dial gauge. The data were submitted to 3-way ANOVA, followed by Tukey's test (p0.05). The highest acid erosion values were registered for Magic Glass, Ion Z, VitroFil and Maxxion R, which exceeded the maximum stipulated by the relevant ISO test (ISO 9917-1). A positive linear correlation (r2=0.4886) was found for both properties, i.e., higher fluoride release is related to higher acid erosion. SIGNIFICANCE: Acid erosion and fluoride release are related properties of GICs, though factors such as pH and P/L ratio lead to differences between actual values for individual brands of these materials

    An observational national study of anaesthetic workload and seniority across the working week and weekend in the UK in 2016: the 6th National Audit Project (NAP6) Activity Survey

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    BACKGROUND: UK national anaesthetic activity was studied in 2013 but weekend working was not examined. Understanding changes since 2013 in workload and manpower distribution, including weekends, would be of value in workforce planning. METHODS: We performed an observational survey of NHS hospitals' anaesthetic practice in October 2016 as part of the 6th National Audit Project of the Royal College of Anaesthetists (NAP6). All cases cared for by an anaesthetist during the study period were included. Patient characteristics and details of anaesthetic conduct were collected by local anaesthetists. RESULTS: Responses were received from 342/356 (96%) hospitals. In total, 15 942 cases were reported, equating to an annual anaesthetic workload of ≈3.13 million cases. Approximately 95% (9888/10 452) of elective and 72% (3184/4392) of emergency work was performed on weekdays and 89% (14 145/15 942) of activity was led by senior (consultant or career grade) anaesthetists and 1.1% (180/15942) by those with <2 yr anaesthetic experience. During weekends case urgency increased, the proportion of healthy patients reduced and case mix changed. Cases led by senior anaesthetists fell to 80% (947/1177) on Saturday and 66% (342/791) on Sunday. Senior involvement in obstetric anaesthetic activity was 69% (628/911) during the week and 45% (182/402) at weekends, compared with 93% (791/847) in emergency orthopaedic procedures during the week and 89% (285/321) at weekends. Since 2013, the proportion of obese patients, elective weekend working, and depth of anaesthesia monitoring has increased [12% (1464/12 213) vs 2.8%], but neuromuscular monitoring has not [37% (2032/5532) vs 38% of paralysed cases]. CONCLUSIONS: Senior clinicians deliver most UK anaesthesia care, including at weekends. Our findings are important for any planned workforce reorganisation to rationalise 7-day working

    Anaesthesia, surgery, and life-threatening allergic reactions: epidemiology and clinical features of perioperative anaphylaxis in the 6th National Audit Project (NAP6)

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    BACKGROUND: Anaphylaxis during anaesthesia is a serious complication for patients and anaesthetists. METHODS: The 6th National Audit Project (NAP6) on perioperative anaphylaxis collected and reviewed 266 reports of Grades 3-5 anaphylaxis over 1 yr from all NHS hospitals in the UK. RESULTS: The estimated incidence was ≈1:10 000 anaesthetics. Case exclusion because of reporting delays or incomplete data means true incidence might be ≈70% higher. The distribution of 199 identified culprit agents included antibiotics (94), neuromuscular blocking agents (65), chlorhexidine (18), and Patent Blue dye (9). Teicoplanin comprised 12% of antibiotic exposures, but caused 38% of antibiotic-induced anaphylaxis. Eighteen patients reacted to an antibiotic test dose. Succinylcholine-induced anaphylaxis, mainly presenting with bronchospasm, was two-fold more likely than other neuromuscular blocking agents. Atracurium-induced anaphylaxis mainly presented with hypotension. Non-depolarising neuromuscular blocking agents had similar incidences to each other. There were no reports of local anaesthetic or latex-induced anaphylaxis. The commonest presenting features were hypotension (46%), bronchospasm (18%), tachycardia (9.8%), oxygen desaturation (4.7%), bradycardia (3%), and reduced/absent capnography trace (2.3%). All patients were hypotensive during the episode. Onset was rapid for neuromuscular blocking agents and antibiotics, but delayed with chlorhexidine and Patent Blue dye. There were 10 deaths and 40 cardiac arrests. Pulseless electrical activity was the usual type of cardiac arrest, often with bradycardia. Poor outcomes were associated with increased ASA, obesity, beta blocker, and angiotensin-converting enzyme inhibitor medication. Seventy per cent of cases were reported to the hospital incident reporting system, and only 24% to Medicines and Healthcare products Regulatory Agency via the Yellow Card Scheme. CONCLUSIONS: The overall incidence of perioperative anaphylaxis was estimated to be 1 in 10 000 anaesthetics

    Cross-sectional study of perioperative drug and allergen exposure in UK practice in 2016: the 6th National Audit Project (NAP6) Allergen Survey.

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    BACKGROUND: Details of the current UK drug and allergen exposure were needed for interpretation of reports of perioperative anaphylaxis to the 6th National Audit Project (NAP6). METHODS: We performed a cross-sectional survey of 356 NHS hospitals determining anaesthetic drug usage in October 2016. All cases cared for by an anaesthetist were included. RESULTS: Responses were received from 342 (96%) hospitals. Within-hospital return rates were 96%. We collected 15 942 forms, equating to an annual caseload of 3.1 million, including 2.4 million general anaesthetics. Propofol was used in 74% of all cases and 90% of general anaesthetics. Maintenance included a volatile agent in 95% and propofol in 8.7%. Neuromuscular blocking agents were used in 47% of general anaesthetics. Analgesics were used in 88% of cases: opioids, 82%; paracetamol, 56%; and non-steroidal anti-inflammatory drugs, 28%. Antibiotics were administered in 57% of cases, including 2.5 million annual perioperative administrations; gentamicin, co-amoxiclav, and cefuroxime were most commonly used. Local anaesthetics were used in 74% cases and 70% of general anaesthetics. Anti-emetics were used in 73% of cases: during general anaesthesia, ondansetron in 78% and dexamethasone in 60%. Blood products were used in ≈3% of cases, gelatin <2%, starch very rarely, and tranexamic acid in ≈6%. Chlorhexidine and povidone-iodine exposures were 74% and 40% of cases, and 21% reported a latex-free environment. Exposures to bone cement, blue dyes, and radiographic contrast dye were each reported in 2-3% of cases. CONCLUSIONS: This survey provides insights into allergen exposures in perioperative care, which is important as denominator data for the NAP6 registry

    Anaesthesia, surgery, and life-threatening allergic reactions: management and outcomes in the 6th National Audit Project (NAP6)

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    BACKGROUND: Anaphylaxis during anaesthesia is a serious complication for patients and anaesthetists. There is little published information on management and outcomes of perioperative anaphylaxis in the UK. METHODS: The 6th National Audit Project of the Royal College of Anaesthetists (NAP6) collected and reviewed 266 reports of Grade 3-5 anaphylaxis from all UK NHS hospitals over 1 yr. Quality of management was assessed against published guidelines. RESULTS: Appropriately senior anaesthetists resuscitated all patients. Immediate management was 'good' in 46% and 'poor' in 15%. Recognition and treatment of anaphylaxis were prompt in 97% and 83% of cases, respectively. Epinephrine was administered i.v. in 76%, i.m. in 14%, both in 6%, and not at all in 11% of cases. A catecholamine infusion was administered in half of cases. Cardiac arrests (40 cases; 15%) were promptly treated but cardiac compressions were omitted in half of patients with unrecordable BP. The surgical procedure was abandoned in most cases, including 10% where surgery was urgent. Of 54% admitted to critical care, 70% were level 3, with most requiring catecholamine infusions. Ten (3.8%) patents (mostly elderly with cardiovascular disease) died from anaphylaxis. Corticosteroids and antihistamines were generally administered early. We found no clear evidence of harm or benefit from chlorphenamine. Two patients received vasopressin and one glucagon. Fluid administration was inadequate in 19% of cases. Treatment included sugammadex in 19 cases, including one when rocuronium had not been administered. Adverse sequelae (psychological, cognitive, or physical) were reported in one-third of cases. CONCLUSIONS: Management of perioperative anaphylaxis could be improved, especially with respect to administration of epinephrine, cardiac compressions, and i.v. fluid. Sequelae were common
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