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Electrochemical treatment of shrimp farming effluent: role of electrocatalytic material Texto completo
2017
de Menezes, Francisco Leonardo Gomes | da Silva, André Jailson Cabral | Martínez-Huitle, Carlos Alberto | Zanta, Carmem Lúcia Paiva Silva | Alves, Janete Jane Fernandes | Castro, Suely Souza Leal
This study investigated the electrochemical oxidation of organic matter present in shrimp farming effluent using three types of electrocatalytic materials: Ti/Ru₀.₃₄Ti₀.₆₆O₂, Ti/Pt, and boron-doped diamond (BDD). An electrochemical cell with 300 mL under stirring agitation was used by applying 20, 40, and 60 mA cm⁻². A Ti/Ru₀.₃₄Ti₀.₆₆O₂ anode showed a reduction of chemical oxygen demand (COD) about 84 % after 1 h of electrolysis, while at the same time, 71 % of COD decay was achieved at Ti/Pt. Conversely, only 71 % of COD was removed after 2 h with a BDD anode. Regarding the temperature effect, BDD showed better performances than those achieved for Ti/Ru₀.₃₄Ti₀.₆₆O₂ and Ti/Pt anodes during an electrochemical treatment of a shrimp farming effluent, obtaining 72 % of COD removal by applying 20 mA cm⁻² at 40 °C after 15 min. Energy consumption and cost were estimated in order to established the engineering applicability of this alternative process.
Mostrar más [+] Menos [-]Photodegradation of ethylene by use of TiO2 sol-gel on polypropylene and on glass for application in the postharvest of papaya fruit Texto completo
2017
Lourenço, Ruth Evelyn R. S. | Linhares, Amanda A. N. | de Oliveira, André Vicente | da Silva, Marcelo Gomes | de Oliveira, Jurandi Gonçalves | Canela, Maria Cristina
The papaya is a commercially important fruit commodity worldwide. Being a climacteric fruit, it is highly perishable. Thus, for the transportation of papaya fruit for long distances without loss of quality, it is necessary to avoid the autocatalytic effect of ethylene in accelerating the ripening of the fruit. This work addresses the application of heterogeneous photocatalysis to the degradation of ethylene. A TiO₂ sol-gel supported on polypropylene (PP) and on glass was used as the catalytic material, and a UV-A lamp was employed as the radiation source. Initially, a concentration of 500 ppbv ethylene was exposed to the catalyst material irradiated by UV-A radiation. A sensitive photoacoustic spectrometer was used to monitor the photocatalytic activity. The TiO₂ sol-gel supported on the glass substrate was more efficient than on the PP in degrading the ethylene. Under direct UV-A exposure, the skin appearance of ‘Golden’ papaya was damaged, depreciating the fruit quality and thus preventing its commercialization. However, the feasibility of the heterogeneous photocatalysis to preserve the fruit quality was achieved when ethylene was removed from the storage ambient using fans, and then, this plant hormone was degraded by a reactor set apart in a ventilation closed system.
Mostrar más [+] Menos [-]Tracking fluorescent components of dissolved organic matter from soils in large-scale irrigated area Texto completo
2017
Pan, Hongwei | Yu, Huibin | Song, Yonghui | Zhu, Lin | Liu, Ruixia | Du, Erdeng
Combination of fluorescence excitation-emission matrix spectroscopy with parallel factor analysis (PARAFAC) and principal component analysis (PCA) was engaged to track fluorescent components of dissolved organic matter (DOM) extracted from soils, to seek potential factors, and to reveal their correlations with physico-chemical properties of soils. Soil samples at different depths were collected in Hetao irrigated area of Inner Mongolia, China. Five fluorescent components (C1 to C5) were identified by PARAFAC modeling of DOM extracted from the soil samples. C1 was referred as fulvic-like fluorescent component, by which DOM was dominated in the whole soil samples. C2 was associated with salinity and agriculture, which was similar to marine humic-like fluorescent component. C3 was assigned as traditional humic-like fluorescent component. The three components were of the terrestrial origin. C4 was involved in tryptophan-like fluorescent component, which was autochthonous productions of biological degradation. C5 might be a polycyclic aromatic hydrocarbon contaminant, which could be relative to anthropogenic sources of pesticides. The C1, C2, and C3 were the potential factors of characterizing DOM fractions using PCA on fluorescent components and physico-chemical parameters. Moreover, DOM might restrained by exchangeable sodium percentage, and its formation and decomposition might be influenced by soil moisture.
Mostrar más [+] Menos [-]Detoxification effects of phytonutrients against environmental toxicants and sharing of clinical experience on practical applications Texto completo
2017
Chung, Raymond Tsz Man
According to the Food and Health Bureau and Trade and Industry Department of the Hong Kong Government, 90 % of the total food supply in Hong Kong was imported from the Mainland China. In addition, the hidden or illegal use of prohibited pesticides, food adulteration (e.g., using industrial salt in food processing, using gutter oil as cooking oil), and pollutions were periodically reported by the media. Excessive exposure to toxic heavy metals or persistent organic pollutants (POPs) from diet or environmental is inevitable amid industrialization and pollution. Understanding of the detoxification ability among nutrients in plant-based food (i.e., phytonutrients in green tea, onion, garlic, coriander, and turmeric) offers therapeutic and preventive effects against the poisoning effects due to these pollutants. Oxidative stress and pro-inflammatory actions are the common mechanisms for heavy metals or POPs toxicities, while phytonutrients counteracts these cellular insults by anti-oxidation, upregulation of anti-inflammatory pathways, and chelation.
Mostrar más [+] Menos [-]Multivariate analysis and geochemical approach for assessment of metal pollution state in sediment cores Texto completo
2017
Jamshidi-Zanjani, Ahmad | Saeedi, Mohsen
Vertical distribution of metals (Cu, Zn, Cr, Fe, Mn, Pb, Ni, Cd, and Li) in four sediment core samples (C₁, C₂, C₃, and C₄) from Anzali international wetland located southwest of the Caspian Sea was examined. Background concentration of each metal was calculated according to different statistical approaches. The results of multivariate statistical analysis showed that Fe and Mn might have significant role in the fate of Ni and Zn in sediment core samples. Different sediment quality indexes were utilized to assess metal pollution in sediment cores. Moreover, a new sediment quality index named aggregative toxicity index (ATI) based on sediment quality guidelines (SQGs) was developed to assess the degree of metal toxicity in an aggregative manner. The increasing pattern of metal pollution and their toxicity degree in upper layers of core samples indicated increasing effects of anthropogenic sources in the study area.
Mostrar más [+] Menos [-]Can toxicants used against cotton mealybug Phenacoccus solenopsis be compatible with an encyrtid parasitoid Aenasius bambawalei under laboratory conditions? Texto completo
2017
Badshah, Hayat | Ullah, Farman | Calatayud, Paul Andre | Ullah, Hidayat | Ahmad, Bashir
The cotton mealybug, Phenacoccus solenopsis Tinsley (Sternorrhyncha: Pseudococcidae) is a serious pest of various cultivated plants in Pakistan. Recent reports show that the parasitoid Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) is a good biocontrol agent of the pest. Compatibleness is important in any IPM programme, and the insecticide used must have little or no effects on the biological control agent. This study investigated the compatibility of neem treatments and a commercial insecticide, imidacloprid on A. bambawalei. Bioassays were laid out in a completely randomized design (CRD) under laboratory conditions. Results showed that the adult stage of the parasitoid was more susceptible to the commercial insecticide imidacloprid than the concealed pupal stage. Moreover, on the basis of the International Organization for Biological Control (IOBC) toxicity categories of the commercial insecticide, imidacloprid was moderately toxic throughout the study period (Ex >80%) while neem was slightly toxic after 24 h of use (Ex <80%). Results also suggest that A. bambawalei release should be delayed for at least 1 week after neem treatments. Because imidacloprid destroys A. bambawalei, it might cause resurgence of P. solenopsis; thus, farmers should avoid integrating the insecticide in the control of P. solenopsis.
Mostrar más [+] Menos [-]Comparison of the trapping effect and antioxidant enzymatic activities using three different light sources in cockchafers Texto completo
2017
Gao, Yan | Li, Ganghua | Li, Kebin | Lei, Chaoliang | Huang, Qiuying
Light traps have been widely used for controlling underground pests. However, very little is known regarding the relationship between trapping effect and antioxidant enzymatic activities using light irradiation in underground pests. Thus, we determined the trapping effect of three light sources of the frequoscillation pest-killing lamp on two species of cockchafers, Serica orientalis Motschulsky (Coleoptera: Melolonthidae) and Anomala corpulenta Motschulsky (Coleoptera: Rutelidae), and evaluated the effect of the same three light sources on the activities of their antioxidant enzymes. The catches of S. orientalis were significantly higher compared to A. corpulenta using light source A in peanut fields in China. After irradiation by light source A, the malondialdehyde (MDA) contents and activities of superoxide dismutase (SOD) and glutathione S-transferases (GST) in S. orientalis were significantly and marginally significantly lower compared to A. corpulenta. Taken together, these results indicated a weaker antioxidant enzyme activity response to light stress and a larger quantity of trapping catches using light irradiation in cockchafers. Thus, we proposed a potential negative relationship between trapping effect and antioxidant enzymatic activities in response to light irradiation in cockchafers.
Mostrar más [+] Menos [-]Multibiomarker responses in aquatic insect Belostoma elegans (Hemiptera) to organic pollution in freshwater system Texto completo
2017
Lavarías, S. | Ocon, C. | van Oosterom, V López | Laino, A. | Medesani, D. A. | Fassiano, A. | Garda, H. | Donadelli, J. | de Molina, M Ríos | Capítulo, A Rodrigues
The present study analyzes a battery of biomarkers in the water bug Belostoma elegans from a stream polluted with organic matter (OMS), and another one considered as reference site (RS) during spring-summer season (December to March). Biochemical parameters of glucidic, lipidic and oxidative metabolic pathways were analyzed in males and females of this insect. In general, no significant differences were observed in all biomarkers assayed between both sexes, except lactate concentration which was higher in males than in females (p < 0.0006) in the first three months. About carbohydrate metabolism parameters, only pyruvate-kinase showed significant differences between insects collected in both streams (p < 0.05) during December. However, the total lipid content, saturated fatty acid, and mainly triacylglycerol were higher in insects from RS compared to those from OMS (p < 0.002) in all sampled months. Levels of lipoperoxidation, protein oxidation, reduced glutathione and glutathione-S-transferase activity showed no differences between insects collected from both streams. Nevertheless, the significant increase observed in superoxide dismutase and catalase activities (p < 0.004) could be due to the elevated oxidative metabolism in insects from RS compared to those from OMS with lower dissolved oxygen. Regarding those responding parameters, males accounted for the differences between the two sites during the study period. In conclusion, our results support that lipidic energetic reserves and antioxidant enzyme activities in B. elegans could be used as biomarkers of environmental pollution by organic matter.
Mostrar más [+] Menos [-]Extraction and representation of common feature from uncertain facial expressions with cloud model Texto completo
2017
Wang, Shuliang | Chi, Hehua | Yuan, Hanning | Geng, Jing
Human facial expressions are key ingredient to convert an individual’s innate emotion in communication. However, the variation of facial expressions affects the reliable identification of human emotions. In this paper, we present a cloud model to extract facial features for representing human emotion. First, the uncertainties in facial expression are analyzed in the context of cloud model. The feature extraction and representation algorithm is established under cloud generators. With forward cloud generator, facial expression images can be re-generated as many as we like for visually representing the extracted three features, and each feature shows different roles. The effectiveness of the computing model is tested on Japanese Female Facial Expression database. Three common features are extracted from seven facial expression images. Finally, the paper is concluded and remarked.
Mostrar más [+] Menos [-]Does trade matter for carbon emissions in OECD countries? Evidence from a new trade openness measure Texto completo
2017
Gözgor, Giray
This paper analyzes the impacts of the per capita income, the per capita energy consumption, and the trade openness on the level of per capita carbon emissions in the panel dataset of 35 Organization for Economic Cooperation and Development (OECD) countries over the period 1960–2013. Along with the nominal trade openness, the paper uses a different trade openness measure, so called as the “trade potential index” (TPI). To the best of our knowledge, this is the first paper that uses the TPI in the empirical environmental Kuznets curve (EKC) hypothesis literature. The paper finds that the EKC hypothesis is valid and there is an “inverted-U” relationship between the income and the carbon emissions. In addition, the paper observes that there is a positive effect of the energy consumption on the carbon emissions. Furthermore, the results indicate that both trade openness measures are negatively associated with the carbon emissions in the OECD countries in the long run.
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