2,457 research outputs found

    Vis LED Photo-Fenton Degradation of 124-Trichlorobenzene at a Neutral pH Using Ferrioxalate as Catalyst

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    Chlorinated organic compounds (COCs) are among the more toxic organic compounds frequently found in soil and groundwater. Among these, toxic and low-degradable chlorobenzenes are commonly found in the environment. In this work, an innovative process using hydrogen peroxide as the oxidant, ferrioxalate as the catalyst and a visible light-emitting diode lamp (Vis LED) were applied to successfully oxidize 124-trichlorobenzene (124-TCB) in a saturated aqueous solution of 124-TCB (28 mg L−1) at a neutral pH. The influence of a hydrogen peroxide (HP) concentration (61.5–612 mg L−1), Fe3+ (Fe) dosage (3–10 mg L−1), and irradiation level (Rad) (I = 0.12 W cm−2 and I = 0.18 W cm−2) on 124-TCB conversion and dechlorination was studied. A D–Optimal experimental design combined with response surface methodology (RSM) was implemented to maximize the quality of the information obtained. The ANOVA test was used to assess the significance of the model and its coefficients. The maximum pollutant conversion at 180 min (98.50%98.50%) was obtained with Fe = 7 mg L−1, HP = 305 mg L−1, and I = 0.12 W cm−2. The effect of two inorganic anions usually presents in real groundwater (bicarbonate and chloride, 600 mg L−1 each) was investigated under those optimized operating conditions. A slight reduction in the 124-TCB conversion after 180 min of reaction was noticed in the presence of bicarbonate (8.31%) and chloride (7.85%). Toxicity was studied with Microtox® (Azur Environmental, Carlsbad, CA, USA) bioassay, and a remarkable toxicity decrease was found in the treated samples, with the inhibition proportional to the remaining 124-TCB concentration. That means that nontoxic byproducts are produced in agreement with the high dechlorination degrees noticed.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEUnión EuropeaComunidad de MadridMinisterio de Ciencia, Innovaciónpu

    An Experience in Integrated Knowledge about Manufacturing Technologies for Students of the Grades of Industrial Engineering

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    AbstractIn the development of the specific skills in the field of industrial engineering, the transversality of the contents of each area of knowledge must be considered. This paper shows how the integration of the contents of different areas (such as materials, manufacturing, design, etc.) is performed in order to allow students to enhance their transversal skills. For this, a specific product is proposed as “learning object”. The analysis, to be made by the students, includes all the aspects regarding technical and economic feasibility, and manufacturing optimization of the product. The article also shows the analysis of the work environment and the established methodology by an interdisciplinary group of university teachers from different areas: materials, manufacturing and design who have contributed with their knowledge in the specific problem

    A two years simulation using a real data cellular automaton: A predictive case study with the schistosomiasis expansion process along the coastline of Brazil

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    This work presents a Cellular Automata model to characterize the social and environmental factors which contribute for the analysis of the expansion process of Schistosoma mansoni infection in Pernambuco - Brazil. The model has been experimented with a set of two years real data from a study area at North Coast of Pernambuco – Brazil. The main constraint equations, the modelling process and the results obtained until now with the simulating scenarios generated are presented here. The results identify, as in field works, endemic areas and human risk infection areas. Furthermore, predictive scenarios for a look ahead with a perspective into fifteen years are also presented.Peer ReviewedPostprint (published version

    New arthroscopic portal for performing tenotomy/tenodesis procedures on the long head of the biceps brachii tendon

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    AbstractBackgroundShoulder arthroscopy is the standard technique for performing procedures involving the intertubercular groove. Current techniques continue to produce excessive soft tissue manipulation and neurovascular injury.Materials and methodsA cross-sectional, observational and descriptive study was conducted on a cohort of 24 shoulders following the standard surgical protocol and using punch dissection. The neurovascular structures with risk of damage by the standard lateral portal were evaluated during the study to establish a secure area for a new arthroscopic portal. Finally, the safety of the new proposed site was evaluated.ResultsThe presence of 24 venous structures, with a mean diameter was 1.05mm (SD: 0.71) was documented. A tendency was observed in locating these structures in the lower half of the dissecting field for the left shoulders and a hypovascular area between the 7 and 10h circle dissected relative to the right shoulder. The new site was determined at a point 1.5cm anterolateral to the anterolateral border of the acromion at an angle of 60° to the horizontal axis of the acromion and towards the intertubercular groove of the humerus.ConclusionsThe methodology used in this study is innovative, reproducible and applicable for the study of all existing shoulder arthroscopic portals procedures, as well as any joint. The results provided by this study will be helpful for clinicians to improve tenotomy/tendon tenodesis procedures of the long head of the biceps brachii tendon

    Uma compreensão etnometodológica de aprendizagem e proficiência em língua adicional

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    Descrevemos ações que configuram o trabalho de aprender espanhol como língua adicional e o trabalho de ser membro em entrevista de proficiência oral em português como língua adicional em duas sequências de fala-em-interação, segmentadas de dois corpora: 24 horas de gravações audiovisuais de aulas de espanhol como língua adicional em uma escola de línguas no Brasil (ABELEDO, 2008) e 10 horas de gravações em áudio de entrevistas de proficiência oral em português como língua adicional do exame Celpe-Bras (FORTES, 2010). Essas análises, representativas de coleções de ambos os corpora, mostram que os participantes utilizam práticas de descrição e categorização (SACKS, 1992; SCHEGLOFF, 2007a) aceitáveis e compreensíveis para manter a sua intersubjetividade (GARFINKEL, 1967), orientando-se para as práticas de descrição e categorização da língua adicional como sendo não apenas aceitáveis, mas preferíveis. A atribuição e a ratificação de categorias de pertencimento (SACKS, 1992; SCHEGLOFF, 2007a) entre os participantes também são comuns a ambos os corpora: para o trabalho de aprender, os participantes atribuem e ratificam categorias institucionais (SCHEGLOFF, 1992) enquanto demonstram copertencimento na comunidade de práticas linguísticas que eles simultaneamente instauram, reorganizando, portanto, a sua participação (GOODWIN; GOODWIN, 2004); para o trabalho de ser membro competente em entrevistas de teste de proficiência linguística, os participantes conferem uns aos outros categorizações localmente relevantes em torno de [ser daqui] e [ser de lá]. Os resultados da análise nos permitem conceber a aprendizagem de língua adicional como trabalho interacional constante que é inseparável da participação. A análise dos dados de entrevistas de proficiência oral aponta para a necessidade de parâmetros de avaliação de proficiência oral em língua adicional cada vez mais válidos e coerentes com a visão de que o uso da linguagem serve para ação no mundo (CLARK, 1996)

    Conduits for myocardial revascularization grafts: the importance of morphology and imaging

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    The therapeutic options for patients with multivessel coronary artery disease, consist of pharmacological treatment, percutaneous coronary intervention and coronary artery bypass graft surgery. The ultimate goal of this surgery is to achieve complete revascularization with conduits that remain permeable for the remainder of the life of the patient. Some of the conduits used in this type of surgery, are the great saphenous vein, the internal thoracic artery, the radial artery and the ulnar artery. For a vascular conduit to be selected as a coronary revascularization graft, it must exhibit the following characteristics: sufficient length, lumen diameter and thickness of the vessel wall. It must also have minimal in situ ischemic consequences and an acceptable permeability over time of the conduit. Recent literatures of these conduits, as well as the importance of morphological and imaging studies are reviewed in this article

    LED visible light assisted photochemical oxidation of HCHs in aqueous phases polluted with DNAPL

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    This work focuses on removing hexachlorocyclohexanes (HCHs) found in groundwater polluted with dense non-aqueous phase liquids (DNAPLs) by photo-oxidation with hydrogen peroxide or persulfate using LED visible light and ferrioxalate as the catalyst. Single oxidation tests were also performed to evaluate the contribution of LED-vis light on HCHs removal. Results show that it is possible to attain the degradation of HCHs up to 85% in 420 min with persulfate, whereas percentages lower than 40% are obtained when using hydrogen peroxide. Using both oxidants in the presence of ferrioxalate and LED visible light promotes the generation of hydroxyl and sulfate radicals under circumneutral pH values, which are the main responsible species for HCHs removal. Specifically, an oxidant conversion higher than 50% was achieved during the photochemical treatment with both oxidants, whereas conversions below 20% were obtained in the absence of LED visible light irradiation. On the other hand, DNAPL produced as liquid residuum of lindane production contains other chlorinated organic compounds (COCs), which are susceptible to being oxidized by hydroxyl and sulfate radicals, generating competitive oxidation reactions. The final conversion of chlorbenzenes reaches values close to 100% and HCHs are only effectively removed when persulfate is used as the oxidant. This better performance indicates that the photo-oxidation of DNAPL polluted groundwater with LED-vis light should be carried out with persulfate to ensure the removal of more dangerous COCs. This confirms the excellent ability of sulfate radicals for C-Cl bond breakdown

    Enhanced remediation of a real HCH-polluted soil by the synergetic alkaline and ultrasonic activation of persulfate

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    The desorption of hydrophobic organic compounds (HOCs) and limited mass transfer in soil systems is a significant challenge for efficient soil remediation by oxidation treatments. The utilization of sonochemistry is a promising technology to enhance the decontamination of HOCs-polluted soils. In this work, ultrasound (US) was coupled to NaOH for activating persulfate (PS) to enhance the remediation of a real soil polluted with hexachlorocyclohexanes (HCHs) (ΣHCHs = 404 mg kg− 1 ). Batch experiments (mass aqueous/soil ratio, VL/WS = 2) were performed to evaluate the effect of US on HOCs desorption and oxidation. Moreover, the influence of US power (0–245 W, corresponding to 0–91 W L-1 of US power density) and the initial oxidant concentration (CPS = 10–60 g L-1) on pollutants abatement, dechlorination degree, and oxidant consumption have been studied. Scanning electron microscopy (SEM) images verified that the US facilitates the breakdown of soil aggregates, enhancing the desorption of trichlorobenzenes (TCBs) (generated from HCHs alkaline hydrolysis) from the soil. Moreover, their subsequent oxidation is favouring because of higher radical species concentrations and the temperature rise. An increase in the US power up to 165 W accelerates the production rate of radicals, improving the pollutants’ degradation. The difference between pollutant oxidation and dechlorination decreases with increasing US power, associated with a lower concentration of intermediate chlorinated compounds. In the same way, the initial oxidant concentration plays a fundamental role in the remediation treatment. At the selected operating conditions (CPS = 60 g L-1, NaOH/PS = 2, 165 W), a pollutants degradation and dechlorination of 0.94 and 0.74, respectively, were achieved in just 3 h of reaction time

    DNA methylation in genes of longevity‐regulating pathways: association with obesity and metabolic complications

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    Aging is the main risk factor for most chronic diseases. Epigenetic mechanisms, such as DNA methylation (DNAm) plays a pivotal role in the regulation of physiological responses that can vary along lifespan. The aim of this research was to analyze the association between leukocyte DNAm in genes involved in longevity and the occurrence of obesity and related metabolic alterations in an adult population. Subjects from the MENA cohort (n=474) were categorized according to age () and the presence of metabolic alterations: increased waist circumference, hypercholesterolemia, insulin resistance, and metabolic syndrome. The methylation levels of 58 CpG sites located at genes involved in longevity‐regulating pathways were strongly correlated (FDR‐ adjusted< 0.0001) with BMI. Fifteen of them were differentially methylated (p<0.05) between younger and older subjects that exhibited at least one metabolic alteration. Six of these CpG sites, located at MTOR (cg08862778), ULK1 (cg07199894), ADCY6 (cg11658986), IGF1R (cg01284192), CREB5 (cg11301281), and RELA (cg08128650), were common to the metabolic traits, and CREB5, RELA, and ULK1 were statistically associated with age. In summary, leukocyte DNAm levels of several CpG sites located at genes involved in longevity‐ regulating pathways were associated with obesity and metabolic syndrome traits, suggesting a role of DNAm in aging‐related metabolic alterations
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