10 research outputs found
DYNAMIC THRESHOLDING GA-BASED ECG FEATURE SELECTION IN CARDIOVASCULAR DISEASE DIAGNOSIS
No full textElectrocardiogram (ECG) data are usually used to diagnose cardiovascular disease (CVD) with the help of a revolutionary algorithm. Feature selection is a crucial step in the development of accurate and reliable diagnostic models for CVDs. This research introduces the dynamic threshold genetic algorithm (DTGA) algorithm, a type of genetic algorithm that is used for optimization problems and discusses its use in the context of feature selection. This research reveals the success of DTGA in selecting relevant ECG features that ultimately enhance accuracy and efficiency in the diagnosis of CVD. This work also proves the benefits of employing DTGA in clinical practice, including a reduction in the amount of time spent diagnosing patients and an increase in the precision with which individuals who are at risk of CVD can be identified
DYNAMIC THRESHOLDING GA-BASED ECG FEATURE SELECTION IN CARDIOVASCULAR DISEASE DIAGNOSIS
No full textElectrocardiogram (ECG) data are usually used to diagnose cardiovascular disease (CVD) with the help of a revolutionary algorithm. Feature selection is a crucial step in the development of accurate and reliable diagnostic models for CVDs. This research introduces the dynamic threshold genetic algorithm (DTGA) algorithm, a type of genetic algorithm that is used for optimization problems and discusses its use in the context of feature selection. This research reveals the success of DTGA in selecting relevant ECG features that ultimately enhance accuracy and efficiency in the diagnosis of CVD. This work also proves the benefits of employing DTGA in clinical practice, including a reduction in the amount of time spent diagnosing patients and an increase in the precision with which individuals who are at risk of CVD can be identified
The inadequacy of consumer protection in the UAE: the need for reform
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis addresses the consumer protection regime in the United Arab Emirates (UAE) against damages posed by defective industrial products, unfair business practices and misleading advertising. Nowadays, unfair and deceptive practices such as the selling of defective or sub-standard goods, the charging of exorbitant prices, misrepresentation of the efficacy or usefulness of goods, and negligence as to safety standards have become rampant. Accordingly, it has become necessary to promote the development and refinement of statutory measures, even in developed countries, to make producers/traders more accountable to consumers. This thesis examines the legal grounds on which consumer protection stands within the newly enacted legal framework for consumer protection in the UAE. In addition, this thesis elaborates upon relevant regulations provided by UAE legislators as well as related laws in selected Arab countries. It further investigates the adequacy of administrative authorities’ measures in the UAE, and explains whether respective administrative rules are capable of compensating consumers for material and physical damages incurred. It also explores the inadequacies of the administration’s measures and rules, and highlights the importance of integration between administrative bodies in achieving a sufficient level of protection for consumers.
The findings of this thesis are based on a detailed review of specific issues in consumer protection models in the Shari’a law and the United Kingdom (UK) model. Thus, it will refer to solutions devised by Islamic Shari’a law and the UK legal system to provide more comprehensive protection to consumers and strengthen their position in relation to that of traders. The study suggests that there is a need to amend the consumer protection in the UAE. It indicates a need for the unified, effective and meaningful implementation of consumer protection legal and administrative procedures in the UAE, and emphasizes that the non-governmental consumer protection association must be given a wider and legal role in supporting the governmental bodies. These findings may help in improving the current consumer protection regime in the UAE as well as reducing infringements committed by traders. This thesis concludes by making recommendations for drafting a comprehensive set of rules in the UAE in the hopes that such recommendations will contribute effectively toward the development of a consumer protection regime in the UAE.Dubai Police Headquarter
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
No full textBackground: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030. Funding: Wellcome Trust
Surgical site infection after gastrointestinal surgery in children: An international, multicentre, prospective cohort study
No full textSurgical site infection (SSI) is one of the most common healthcare-associated infections (HAIs). However, there is a lack of data available about SSI in children worldwide, especially from low-income and middle-income countries. This study aimed to estimate the incidence of SSI in children and associations between SSI and morbidity across human development settings
Use of Telemedicine for Post-discharge Assessment of the Surgical Wound: International Cohort Study, and Systematic Review with Meta-analysis
No full textObjective: This study aimed to determine whether remote wound reviews using telemedicine can be safely upscaled, and if standardised assessment tools are needed. Summary background data: Surgical site infection is the most common complication of surgery worldwide, and frequently occurs after hospital discharge. Evidence to support implementation of telemedicine during postoperative recovery will be an essential component of pandemic recovery. Methods: The primary outcome of this study was surgical site infection reported up to 30-days after surgery (SSI), comparing rates reported using telemedicine (telephone and/or video assessment) to those with in-person review. The first part of this study analysed primary data from an international cohort study of adult patients undergoing abdominal surgery who were discharged from hospital before 30-days after surgery. The second part combined this data with the results of a systematic review to perform a meta-analysis of all available data conducted in accordance with PRIMSA guidelines (PROSPERO:192596). Results: The cohort study included 15,358 patients from 66 countries (8069 high, 4448 middle, 1744 low income). Of these, 6907 (45.0%) were followed up using telemedicine. The SSI rate reported using telemedicine was slightly lower than with in-person follow-up (13.4% vs. 11.1%, P<0.001), which persisted after risk adjustment in a mixed-effects model (adjusted odds ratio: 0.73, 95% confidence interval 0.63-0.84, P<0.001). This association was consistent across sensitivity and subgroup analyses, including a propensity-score matched model. In nine eligible non-randomised studies identified, a pooled mean of 64% of patients underwent telemedicine follow-up. Upon meta-analysis, the SSI rate reported was lower with telemedicine (odds ratio: 0.67, 0.47-0.94) than in-person (reference) follow-up (I2=0.45, P=0.12), although there a high risk of bias in included studies. Conclusions: Use of telemedicine to assess the surgical wound post-discharge is feasible, but risks underreporting of SSI. Standardised tools for remote assessment of SSI must be evaluated and adopted as telemedicine is upscaled globally
Exploring the cost-effectiveness of high versus low perioperative fraction of inspired oxygen in the prevention of surgical site infections among abdominal surgery patients in three low- and middle-income countries
No full textBackground: This study assessed the potential cost-effectiveness of high (80–100%) vs low (21–35%) fraction of inspired oxygen (FiO2) at preventing surgical site infections (SSIs) after abdominal surgery in Nigeria, India, and South Africa. Methods: Decision-analytic models were constructed using best available evidence sourced from unbundled data of an ongoing pilot trial assessing the effectiveness of high FiO2, published literature, and a cost survey in Nigeria, India, and South Africa. Effectiveness was measured as percentage of SSIs at 30 days after surgery, a healthcare perspective was adopted, and costs were reported in US dollars (216 compared with 6 (95% confidence interval [CI]: −1) difference in costs. In India, the average cost for high FiO2 was 195 for low FiO2 leading to a −15 to −1164 compared with 93 (95% CI: −65) difference in costs. The high FiO2 arm had few SSIs, 7.33% compared with 8.38% for low FiO2, leading to a −1.05 (95% CI: −1.14 to −0.90) percentage point reduction in SSIs. Conclusion: High FiO2 could be cost-effective at preventing SSIs in the three countries but further data from large clinical trials are required to confirm this
Producción y caracterización de un material compuesto a base de partículas de magnetita y matrices de caucho nitrilo butadieno
No full textEste trabajo describe la fabricación de compuestos conformados a partir de matrices de nitrilo butadieno reforzadas con partículas de magnetita sintética o mineral en diferentes cantidades. Para después, estudiar sus propiedades morfológicas, estructurales, térmicas, eléctricas, magnéticas y de blindaje electromagnético. Materiales compuestos de esta clase son empleados en la producción de componentes electrónicos, polímeros con memoria de forma, y fundamentalmente para la producción de atenuadores de radiación electromagnética en aplicaciones de defensa militar pasiva, construcción de edificios, barcos, aviones y otros vehículos de transporte.
Los compuestos se fabricaron empleando el método de estado fundido. Los refuerzos de magnetita mineral o sintética, según el caso, fueron adicionados en diferentes proporciones 5, 10, 20, 30 y 40 phr. Se utilizó una prensa vulcanizadora con el fin de curar los compuestos y moldearlos según la geometría requerida. El estudio de las propiedades de los materiales fabricados se llevó a cabo a través de difracción de rayos X (DRX), microscopía electrónica FESEM-FIB, espectroscopía fotoelectrónica de rayos X (XPS), análisis termogravimétrico (TGA), calorimetría diferencial de barrido (DSC), espectroscopía Raman, resistividad superficial, estudios de magnetización en función de la temperatura y el campo aplicado, así como estudios de blindaje electromagnético.
La información obtenida de la caracterización DRX permite establecer la transición estructural amorfo-cristalina que experimentan los compuestos al incrementarse la cantidad de magnetita adicionada en la matriz de caucho nitrilo butadieno. El análisis morfológico llevado a cabo por medio de la microscopía electrónica permite establecer las diferencias de aspecto y forma de los refuerzos. Estas diferencias repercuten en la dispersión de los precursores al interior de la matriz y consecuentemente afectan las propiedades de los compuestos.
A través de la espectroscopía Raman se estudió los cambios estructurales en los compuestos debido a las interacciones entre los refuerzos y las cadenas poliméricas de la matriz. Con la técnica XPS se ejecutó el análisis elemental de los precursores y los compuestos, pero sobre todo fue empleada para identificar las posibles interacciones en la interfaz matriz-refuerzo o entre los diferentes elementos que componen los materiales. Dichas interacciones tienen su origen en la reactividad superficial de la magnetita. El análisis térmico de los diferentes materiales compuestos a partir de las técnicas TGA y DSC, permitió identificar como la estabilidad térmica aumenta y la temperatura de transición vítrea de los materiales pasa a menores temperaturas al ser mayores las cantidades de magnetita adicionadas.
Las medidas de resistividad eléctrica permitieron observar una reducción en la resistividad superficial de los materiales con 20 phr de magnetita de hasta dos órdenes de magnitud, respecto a los materiales con menor contenido de ferrita. Las propiedades de apantallamiento electromagnético fueron evaluadas en la banda X de frecuencia (8-12 GHz) y banda K (18-27 GHz), observándose atenuaciones superiores a los 34 dB para los compuestos con mayor cantidad de magnetita. Finalmente, las propiedades magnéticas de los compuestos muestran como la magnetización de saturación y de remanecía, al igual que la susceptibilidad y la permeabilidad magnética son dependientes de la cantidad de magnetita adicionada en la matriz. Siendo en todos los casos estas variables superiores en los materiales constituidos por magnetita artificial, debido a su mejor dispersión y homogeneidad al interior de la matriz de caucho.This work describes the production of a composite material made up of from a nitrile butadiene matrix reinforced with particles of synthetic or mineral magnetite in different quantities, in order to evaluate its structural, morphological, thermal, electrical, magnetic and electromagnetic shielding properties. Composite materials of this type are used for electronic components manufacturing, shape memory polymers and especially for the production of electromagnetic shielding materials in passive military defense applications, building construction, ships, airplanes and other vehicles.
Composite materials were manufactured following the melt mixing method. Magnetite reinforcements fillers were added in different ratios 5, 10, 20, 30 and 40 phr. Composite materials with natural magnetite and synthetic magnetite have been considered separately. After the composites production, a vulcanizing press machine was used in order to cure the samples according to the required geometry. Composites characterization was carried out through X-ray diffraction studies, field emission scanning electron microscopy, Raman spectroscopy, X-ray photoelectronic spectroscopy, differential scanning calorimetry, thermogravimetric analysis, resistivity, magnetization and electromagnetic shielding studies.
The results obtained by DRX show an amorphous-crystalline structural transition between the samples with the increase in the magnetite filler added to the butadiene nitrile rubber matrix. The morphological analysis allows to establish the differences in size and shape between both kinds of magnetite fillers (synthetic and mineral). These differences influence its dispersion within the matrix and consequently affect the composite properties.
Structural changes in the composites due to the interactions between fillers and the polymeric chains of the matrix were studied through Raman spectroscopy. X-ray photoelectronic spectroscopy (XPS) was used for the elemental analysis of the composites and reagents. Also, with this technique it was possible to the identify the possible interactions in the matrix-reinforcement interface or between the fillers. These interactions were created due to the high surface reactivity of magnetite. The composites thermal analysis was carried out through thermogravimetry studies and differential scanning calorimetry; both techniques allowed to identify how the thermal stability increases and the glass transition temperature moves towards lower temperatures as the magnetite within the matrix increases.
The electrical resistivity measurements show a drop in the surface resistivity of the samples of up to three orders of magnitude in the composites reinforced with 20 phr of synthetic magnetite and two orders of magnitude in the composites reinforced with 20 phr of mineral magnetite. The analysis of the magnetic properties of the composites show how the saturation magnetization, remanence magnetization, susceptibility and permeability are directly related with the amount of magnetite within the matrix. The composites reinforced with artificial magnetite has better magnetic properties due to its better dispersion and homogeneity. The electromagnetic shielding properties were evaluated in the X band of frequency (8-12 GHz) and K band (18-27 GHz). It is possible to identify in the composites with the highest amounts of magnetite attenuations greater than 34 dB.Línea de Investigación: Nuevos materiales: Materiales Compuestos de Matriz PoliméricaDoctorad
Global warming and malaria: a call for accuracy
No full textFor more than a decade, malaria has held a prominent place in speculations on the impacts of global climate change. Mathematical models that “predict? increases in the geographic distribution of malaria vectors and the prevalence of the disease have received wide publicity. Efforts to put the issue into perspective1, 2, 3, 4 and 5 are rarely quoted and have had little influence on the political debate. The model proposed by Frank C Tanser and colleagues6 in The Lancet and the accompanying Commentary by Simon Hales and Alistair Woodward7 are typically misleading examples.The relation between climate and malaria transmission is complex and varies according to location,2 yet Tanser et al base their projections on thresholds derived from a mere 15 African locations. Slight adjustments of values assigned to such thresholds and rules can influence spatial predictions strongly.8 The authors invest considerable effort in assessing the sensitivity of their model to climate change scenarios but do not report the internal sensitivities to thresholds and rules. The predictive skill of their model is low (63% sensitivity, 95% CI 61–65%) but they consider projections acceptable if prevalence is projected “to within a month? (presumably +/- 1 month?), thereby biasing their model towards success. A model covering an entire year in a parasite-positive site would always be correct, although in such areas it would be relatively insensitive to climate. By contrast, sites in which transmission is seasonal would provide a more reliable test of accuracy, but estimation is more difficult because climate sensitivity is greater. Furthermore, because parasite clearance in communities is not instantaneous,9 spot samples of parasitaemia on survey dates are not a suitable indicator of the duration of the transmission season. Lastly, “person/months? are unsuitable as a measure of transmission: an extension of season from 1 to 4 months will have more impact than from 10 to 12 months. According to their model, an extension of transmission from 11 to 12 months results in 106 more person/months in a population of 106 people, whereas an extension from 1 to 5 months gives the same increase in a population of 250·000.What Tanser and colleagues have modelled is merely the duration of the transmission season, which they interpret as “heightened transmission? and increased incidence. A greater failing is their reliance on “parasite-ratio studies?. The relations between transmission season and parasite prevalence, and parasite prevalence and clinical disease, are unclear but unlikely to be linear. Moreover, they use 1995 data for human populations, although these are projected to double by 2030. In addition, the proportion living in urban areas—with a specific climate10 and orders of magnitude less malaria transmission11 and 12—is projected to rise from 37% to 53%.13 For all these reasons, we do not accept the model as a “baseline against which interventions can be planned?.It is regrettable that many involved in this debate ignore the rich heritage of literature on the subject. For example, in 1937, in his classic textbook,14 L W Hackett stated: “Everything about malaria is so moulded and altered by local conditions that it becomes a thousand different diseases and epidemiological puzzles. Like chess, it is played with a few pieces, but is capable of an infinite variety of situations?. A pressing question in Hackett's time was the changing distribution of the disease in Europe. On the role of climate, he wrote: “Certainly, climate lays down the broad lines of malaria distribution…Nevertheless, although this is a very simple and plausible explanation…even the early malariologists felt that there was something unsatisfactory about it…malaria has not so much receded as it has contracted, oftentimes toward the north…Thus in Germany it is the northern coast which is still malarious, the south is free…There is, therefore, no climatic reason why (malaria) should have abandoned south Germany or the French Riviera?.We quote Hackett because we feel that the classic components of science—unbiased observation and systematic experimentation—cannot be sidestepped with models that omit many of his chess pieces. Yet Hales and Woodward7 begin by stating: “The present geographical distribution of malaria is explained by a combination of environmental factors (especially climate) and social factors (such as disease-control measures)?. In our opinion, “even the early malariologists? would surely disagree: much of the decline of malaria in Europe took place without control measures during a period when the climate was warming.The text by Hales and Woodward that follows displays a lack of knowledge. Thus, “Most people at risk of malaria live in areas of stable transmission…? is simply wrong. It is true that in many parts of the world malaria is termed “stable? because transmission remains relatively constant from year to year, the disease is endemic, the collective immunity is high, and epidemics are uncommon. However, in many other regions, the disease is endemic but “unstable? because annual transmission varies considerably, and the potential for epidemics is great. Climatic factors, particularly rainfall, are sometimes, but by no means always, relevant.15Again, “On the fringes of endemic zones, where transmission is limited by rainfall…there are strong seasonal patterns, and occasional major epidemics? is also wrong. In many regions, far from any “fringes?, malaria is endemic, stable, but highly seasonal. For example, in semi-arid regions of Mali, transmission is restricted to the rainy season, from July to September. The same 3 months constituted the transmission season for Plasmodium falciparum in Italy before it was eliminated.16 Paradoxically, in parts of the Sudan, rainfall is restricted to a month at most, but malaria is transmitted throughout the year. Female Anopheles gambiae survive drought and heat by resting in dwellings and other sheltered places.17 Blood feeding and transmission continue, but the mosquitoes do not develop eggs until the rains return. This phenomenon, termed gonotrophic dissociation, is remarkably similar to the winter survival strategy of Anopheles atroparvus, the principal vector of malaria in Holland until the mid 20th century.16By contrast, malaria is unstable in many regions that normally have abundant rainfall, and epidemics occur during periods of drought. An illustrative example is the catastrophic 1934–35 epidemic in Ceylon (now Sri Lanka), estimated to have killed 100·000 people.18 Worst hit was the south-western quadrant of the country, where average annual rainfall is greater than 250 cm, and malaria was endemic, but unstable and relatively infrequent. The dominant vector, Anopheles culicifacies, breeds along the banks of rivers and tends to be scarce in normal years. In the years 1928–33 there was abundant rainfall, river flow was high, A culicifacies was rare, and the human population was exceptionally malaria-free. However, after failure of two successive monsoons, the drying rivers produced colossal numbers of A culicifacies, and the resulting epidemic was exacerbated by the low collective immunity. In the drier parts of the island, where A culicifacies was dominant but transmission was more stable, immunity protected the population from the worst ravages of the disease.Hales and Woodward state that “the underlying problem? of the future “extension of seasonality? of malaria is “pollution of the atmosphere?, and call for rich countries to “recognise their obligations to the poorest by substantially reducing fossil-fuel consumption?. We understand public anxiety about climate change, but are concerned that many of these much-publicised predictions are ill informed and misleading. We urge those involved to pay closer attention to the complexities of this challenging subject. <br/
