923 resultados para Pt-based nanoparticles
Resumo:
The Routines-Based Interview (RBI) is useful for developing functional outcomes/goals, for establishing strong relationships with families, and for assessing the family’s true needs. In this study, the authors investigated the psychometric properties of the RBI Implementation Checklist, conducted by 120 early intervention professionals, specifically looking at the probability of correct responses on the items as a logistic function of the difference between the person and the item parameters.We selected Rasch analysis (Rasch, 1980) for this study so we could answer questions about both how themeasure performed and how the interviewers performed and we related these performances to one another. Results indicate that scores on the RBI Implementation Checklist were reliable. The checklist could possibly benefit from more difficult items to measure the true performance of the few people who had scores higher than the most difficult items and also from additional items that focus on the family.
Resumo:
A method provided for the deposition of nanostructured ZnO on cotton fabric to introduce antibacterial functionality was presented in this article. This strategy enabled fabric to be coated with inorganic-based functional materials through in situ synthesis of nanoparticles using ultrasonic irradiation. The amino-terminated silicon sol (AEAPTS) was employed to generate nanostructured ZnO, and the mechanism of the ultrasound-assisted coating was proposed. Antibacterial activities, UV protection and other properties of ZnO-loaded cotton characterized by SEM, FTIR, XRD and TGA were investigated. The results indicated that ZnO-loaded cotton exhibited excellent UV protective property, efficient antibacterial activities, well water-resistant effect, together with moderate cytotoxicity against L929 and lower tensile strength. The developed method provides not only a facile way for in situ synthesis of ZnO on textile but also the production of antibacterial materials for healthcare applications.
Resumo:
Biofilm bacteria are more resistant to antibiotics than planktonic cells. Propolis possesses antimicrobial activity. Generally, nanoparticles containing heavy metals possess antimicrobial and antibiofilm properties. In this study, the ability of adherence of Methicillin Resistant Strains of Staphylococcus aureus (MRSA) to catheters treated with magnetite nanoparticles (MNPs), produced by three methods and functionalized with oleic acid and a hydro-alcoholic extract of propolis from Morocco, was evaluated. The chemical composition of propolis was established by gas chromatography mass spectrometry (GC-MS), and the fabricated nanostructures characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Mossbauer spectroscopy and Fourrier transform infrared spectroscopy (FTIR). The capacity for impairing biofilm formation was dependent on the strain, as well as on the mode of production of MNPs. The co-precipitation method of MNPs fabrication using Fe(3+) and Na₂SO₃ solution and functionalized with oleic acid and propolis was the most effective in the impairment of adherence of all MRSA strains to catheters (p < 0.001). The adherence of the strain MRSA16 was also significantly lower (p < 0.001) when the catheters were treated with the hybrid MNPs with oleic acid produced by a hydrothermal method. The anti-MRSA observed can be attributed to the presence of benzyl caffeate, pinocembrin, galangin, and isocupressic acid in propolis extract, along with MNPs. However, for MRSA16, the impairment of its adherence on catheters may only be attributed to the hybrid MNPs with oleic acid, since very small amount, if any at all of propolis compounds were added to the MNPs.
Resumo:
The use of biological processes with the aim of the recovery of gold from low-concentration solutions derived from leaching of secondary sources is gaining increasing importance owing to the scarcity of the primary resources and the economic and environmental advantages usually presented by these methods. Thus, the addition in batch and continuous processes of different solutions containing biogenic sulphide, which was generated by the activity of sulphate-reducing bacteria (SRB), to gold(III) solutions was investigated for that purpose. In the batch experiments, AuS nanoparticles with sizes of between 6 and 14 nm were obtained (corresponding to 100% removal of Au(III) from solution) if the biogenic sulphide was generated in a typical nutrient medium for SRB, whereas Au(0) nanoparticles with sizes of below 8 nm were obtained (corresponding to 62% removal of Au(III)) if effluent from a SRB bioremediation process for treating acid mine drainage (AMD) was used instead. These results stimulated the development of a continuous process of addition, in which two sulphide-rich effluents, which resulted from a SRB bioremediation process for treating two types of AMD (from a uranium mine and a polysulphide mine), were tested. In both cases, Au(0) nanoparticles with sizes of between 6 and 15 nm were mainly obtained, and the percentage removal of Au(III) from solution ranged from 76% to 100%. The processes described allow the simultaneous treatment of AMD and recovery of metallic gold nanoparticles, which are a product with a wide range of applications (e.g., in medicine, optical devices and catalysis) and high economic value. The synthesis process described in this work can be considered as novel, because it is the first time, to our knowledge, that the use of effluent from a SRB bioremediation process has been reported for the recovery of gold(III) as gold(0) nanoparticles.
Resumo:
OBJECTIVES: The aims of this study were to establish a Colombian smoothed centile charts and LMS tables for tríceps, subscapular and sum tríceps+subscapular skinfolds; appropriate cut-offs were selected using receiver operating characteristic analysis based in a populationbased sample of schoolchildren in Bogota, Colombia and to compare them with international studies. METHODS: A total of 9 618 children and adolescents attending public schools in Bogota, Colombia (55.7% girls; age range of 9–17.9 years). Height, weight, body mass index (BMI), waist circumference, triceps and subscapular skinfold measurements were obtained using standardized methods. We have calculated tríceps+subscapular skinfold (T+SS) sum. Smoothed percentile curves for triceps and subscapular skinfold thickness were derived by the LMS method. Receiver operating characteristics curve (ROC) analyses were used to evaluate the optimal cut-off point of tríceps, subscapular and sum tríceps+subscapular skinfolds for overweight and obesity based on the International Obesity Task Force (IOTF) definitions. Data were compared with international studies. RESULTS: Subscapular, triceps skinfolds and T+SS were significantly higher in girls than in boys (P <0.001). The median values for triceps, subscapular as well as T+SS skinfold thickness increased in a sex-specific pattern with age. The ROC analysis showed that subscapular, triceps skinfolds and T+SS have a high discrimination power in the identification of overweight and obesity in the sample population in this study. Based on the raw non-adjusted data, we found that Colombian boys and girls had high triceps and subscapular skinfolds values than their counterparts from Spain, UK, German and US. CONCLUSIONS: Our results provide sex- and age-specific normative reference standards for the triceps and subscapular skinfold thickness values in a large, population-based sample of 3 schoolchildren and adolescents from an Latin-American population. By providing LMS tables for Latin-American people based on Colombian reference data, we hope to provide quantitative tools for the study of obesity and its complications.
Resumo:
The International FItness Scale (IFIS) is a self-reported measure of physical fitness that could easily. This scale has been validated in children, adolescents, and young adults; however, it is unknown whether the IFIS represents a valid and reliable estimate of physical fitness in Latino-American youth population. In the present study we aimed to examine the validity and reliability of the IFIS on a population-based sample of schoolchildren in Bogota, Colombia. Participants were 1,875 Colombian youth (56.2% girls) aged 9 to 17.9 years old. We measured adiposity markers (body fat, waist-to-height ratio, skinfold thicknesses and BMI), blood pressure, lipids profile, fasting glucose, and physical fitness level (self reported and measured). Also, a validated cardiometabolic risk index was used. An age- and sex-matched sample of 229 Schoolchildren originally not included in the study sample fulfilled IFIS twice for reliability purposes. Our data suggest that both measured and self-reported overall fitness were associated inversely with adiposity indicators and a cardiometabolic risk score. Overall, schoolchildren who self-reported “good” and “very good” fitness had better measured fitness than those who reported “very poor” and “poor” fitness (all p<0.001). Test–retest reliability of IFIS items was also good, with an average weighted Kappa of 0.811. Therefore, our findings suggest that self-reported fitness, as assessed by IFIS, is a valid, reliable, and health-related measure, and it can be a good alternative for future use in large studies with Latin-schoolchildren from Colombia.
Resumo:
The search for cleaner processes is one of the major challenges in modern chemical industries. In this context clay derived materials are environmentally friendly catalysts that can be easily tailored to optimize their catalytic activity for a precise reaction of interest. Furthermore, clay-based catalysts can be easily separated, recovered and reused and their versatility, low cost, high catalytic activity and/or selectivity render them very attractive materials. Considering that the stability towards water vapour is a crucial aspect for catalytic performance and reuse of the catalysts, we present a study of the pore structure stability, in the presence of water vapour, of clay catalysts prepared by acid activation with HCl solutions and ion-exchange with sodium, aluminium and iron, from a natural clay collected at Serra de Dentro (Porto Santo Island, Portugal) [1]. For elucidating the influence of water vapour on the pore structure stability, water vapour adsorption- -desorption isotherm, at 298 K, was determined on each sample by gravimetric method as well as n-pentane adsorption−desorption isotherms, at 298 K, which were determined before and after the corresponding water adsorption-desorption isotherms. Prior to the measurements, the samples were outgassed during 5 h at 473 K and the adsorptives were outgassed by repeated freeze–thaw cycles. The results to be reported in the communication allow us to state that, upon contact with water vapour, the less acid activated catalysts suffered some reduction in pore volume reflecting changes in the pore structure, while the more acid activated catalysts and those prepared by ion-exchange presented excellent stability upon one cycle of water vapour adsorption-desorption. The results are corroborated by nitrogen adsorption-desorption isotherms determined, at 77 K, before and after the water and n-pentane adsorption-desorption measurements.
Resumo:
The length of stay of preterm infants in a neonatology service has become an issue of a growing concern, namely considering, on the one hand, the mothers and infants health conditions and, on the other hand, the scarce healthcare facilities own resources. Thus, a pro-active strategy for problem solving has to be put in place, either to improve the quality-of-service provided or to reduce the inherent financial costs. Therefore, this work will focus on the development of a diagnosis decision support system in terms of a formal agenda built on a Logic Programming approach to knowledge representation and reasoning, complemented with a case-based problem solving methodology to computing, that caters for the handling of incomplete, unknown, or even contradictory in-formation. The proposed model has been quite accurate in predicting the length of stay (overall accuracy of 84.9%) and by reducing the computational time with values around 21.3%.
Resumo:
The nosocomial infections are a growing concern because they affect a large number of people and they increase the admission time in healthcare facilities. Additionally, its diagnosis is very tricky, requiring multiple medical exams. So, this work is focused on the development of a clinical decision support system to prevent these events from happening. The proposed solution is unique once it caters for the explicit treatment of incomplete, unknown, or even contradictory information under a logic programming basis, that to our knowledge is something that happens for the first time.
Resumo:
Due to the high standards expected from diagnostic medical imaging, the analysis of information regarding waiting lists via different information systems is of utmost importance. Such analysis, on the one hand, may improve the diagnostic quality and, on the other hand, may lead to the reduction of waiting times, with the concomitant increase of the quality of services and the reduction of the inherent financial costs. Hence, the purpose of this study is to assess the waiting time in the delivery of diagnostic medical imaging services, like computed tomography and magnetic resonance imaging. Thereby, this work is focused on the development of a decision support system to assess waiting times in diagnostic medical imaging with recourse to operational data of selected attributes extracted from distinct information systems. The computational framework is built on top of a Logic Programming Case-base Reasoning approach to Knowledge Representation and Reasoning that caters for the handling of in-complete, unknown, or even self-contradictory information.
Resumo:
Waiting time at an intensive care unity stands for a key feature in the assessment of healthcare quality. Nevertheless, its estimation is a difficult task, not only due to the different factors with intricate relations among them, but also with respect to the available data, which may be incomplete, self-contradictory or even unknown. However, its prediction not only improves the patients’ satisfaction but also enhance the quality of the healthcare being provided. To fulfill this goal, this work aims at the development of a decision support system that allows one to predict how long a patient should remain at an emergency unit, having into consideration all the remarks that were just stated above. It is built on top of a Logic Programming approach to knowledge representation and reasoning, complemented with a Case Base approach to computing.
Resumo:
Thrombophilia stands for a genetic or an acquired tendency to hypercoagulable states that increase the risk of venous and arterial thromboses. Indeed, venous thromboembolism is often a chronic illness, mainly in deep venous thrombosis and pulmonary embolism, requiring lifelong prevention strategies. Therefore, it is crucial to identify the cause of the disease, the most appropriate treatment, the length of treatment or prevent a thrombotic recurrence. Thus, this work will focus on the development of a diagnosis decision support system in terms of a formal agenda built on a logic programming approach to knowledge representation and reasoning, complemented with a case-based approach to computing. The proposed model has been quite accurate in the assessment of thrombophilia predisposition risk, since the overall accuracy is higher than 90% and sensitivity ranging in the interval [86.5%, 88.1%]. The main strength of the proposed solution is the ability to deal explicitly with incomplete, unknown, or even self-contradictory information.
Resumo:
It is well known that rib cage dimensions depend on the gender and vary with the age of the individual. Under this setting it is therefore possible to assume that a computational approach to the problem may be thought out and, consequently, this work will focus on the development of an Artificial Intelligence grounded decision support system to predict individual’s age, based on such measurements. On the one hand, using some basic image processing techniques it were extracted such descriptions from chest X-rays (i.e., its maximum width and height). On the other hand, the computational framework was built on top of a Logic Programming Case Base approach to knowledge representation and reasoning, which caters for the handling of incomplete, unknown, or even contradictory information. Furthermore, clustering methods based on similarity analysis among cases were used to distinguish and aggregate collections of historical data in order to reduce the search space, therefore enhancing the cases retrieval and the overall computational process. The accuracy of the proposed model is satisfactory, close to 90%.
Resumo:
This paper aims to establish possible tourism demand scenarios of European travellers to Portugal based on the relationship with changing population structures. A combination of the EuROBAROMETER report 370 (“Attitudes of Europeans towards Tourism in 2013”) and the cohort-component method for population projections will allow the development of different possible tourism demand scenarios. Following the European report, individuals who travelled in 2013 were most likely to live in a household with two or more individuals. Thus, if elderly couples are together till later in their life and in better physiological shape, it is possible that the number of elderly individuals travelling for tourism purposes will increase in the near future. If we can expect tourists from developing countries to be younger due to their demographic dynamics than those from developed countries, where the ageing population is growing fast, we can expect that the percentage of the elderly among tourists will increase. Furthermore, the 2013 European report found that the combination of socio-demographic variables, such as, age, population, gender, household dimension, country of residence and trip purpose explained tourism demand scenarios for Portugal, confirming that seniors and families evidence a paramount sense of importance for the destination. In the literature there is a lack of discussion about the effects of demography in the future and the role of an ageing population in tourism demand choice patterns. We aim to contribute to filling this gap. Consequently, we strongly believe that this paper contributes to the literature by introducing a new field of discussion about the importance of demographic changes in shaping travel trends.
Reductive dechlorination of TCE and cis-DCE by zero-valent iron and iron-based bimetallic reductants
Resumo:
CEs are the most frequently detected pollutants in groundwater. Several studies have been shown iron-based bimetallic reductants as a good method toward to chlorinated ethylenes degradation. However, many fundamental issues surrounding the chemistry of this phenomena remains elusive. In this study, kinetics and compound specific isotope analysis for reductive dechlorination of TCE and cis-DCE by unamended iron and iron-based bimetal reductants was evaluated. Generally, all the bimetals reductants tested revealed to increase the reactivity of the degradation, in which palladium and nickel were the additional metals more reactive. Ethene and ethane were the major products of TCE degradation. It is supported the simultaneous hydrogenolysis and β-elimination reaction hypothesis, however, the first step of TCE degradation by Au/Fe undergoes preferably by β-elimination, while by unamended iron, Pt/Fe and Co/Fe goes preferably by hydrogenolysis. No apparent elucidation was obtained to explain the high reactivity on bimetals systems; Degradação do TCE e cis-DCE por ferro de valência zero e redutores bimetálicos à base de ferro Resumo: Etilenos clorados são os poluentes mais frequentemente detetados na água subterrânea. Vários estudos têm mostrado que redutores bimetálicos à base de ferro são um bom método para a degradação dos etilenos clorados. Porém, muitas questões fundamentais acerca da química deste fenómeno permanecem elusivas. Neste estudo foi avaliada a cinética e a análise isotópica de compostos específicos para a degradação do TCE e cis-DCE por ferro e redutores bimetálicos à base de ferro. Genericamente, os redutores bimetálicos mostraram aumentar a reatividade da degradação, sendo paládio e níquel os metais adicionais mais reativos. Os produtos principais da degradação do TCE foram eteno e etano. É apoiada a hipótese da simultaneidade de hidrogenólise e β-eliminação, porém, o primeiro passo da degradação do TCE por Au/Fe é realizada preferencialmente por β-eliminação, enquanto por ferro, Pt/Fe e Co/Fe é realizada preferencialmente por hidrogenólise. Não houve uma elucidação aparente para explicar a reatividade nos sistemas bimetálicos.