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The aim of this work was to study the degradation of three azo dyes, Orange II, Methyl red and Biebrich Scarlet by electro-Fenton and the effect of the electrochemical pretreatment on the biodegradability of the solutions. The electrochemical pretreatment showed that an electrochemical reduction on the carbon felt electrode was mainly responsible for the decolorization of the azo dyes. Indeed, the electrochemical behaviour of the azo dyes highlighted their electroactivity; electrolysis with and without ferric ions led to the same decolorization yield, namely 99 % at 15 min for Methyl red, and stable chemical oxygen demand (COD) values were recorded during decolorization. In a second step and owing to the absence of by-product electroactivity in reduction, the formation of hydroxyl radicals by the Fenton reaction led to the oxidation of by-products from the electrochemical reduction. It was illustrated by the decrease recorded for the COD values. The results also showed that the azo bond cleavage occurring during the electrochemical reduction was not sufficient to significantly reduce recalcitrance, as shown from biological oxygen demand (BOD)5/COD ratio examination below the limit of biodegradability (0.4). Contrarily, a positive trend was recorded for Orange II during the electro-Fenton reaction, with a BOD5/COD ratio of 0.81 after 28 h of pretreatment. 相似文献
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Saravana Periaswamy Sivagnanam Shipeng Yin Jae Hyung Choi Yong Beom Park Hee Chul Woo Byung Soo Chun 《Marine drugs》2015,13(6):3422-3442
The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO2 (SC-CO2) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO2 method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO2 (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO2 oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO2. The acetone–methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO2 extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process. 相似文献
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Jayanthi Marappan Balasubramaniam Ambattaiyanpatti Anathaikamatchi Suryaprakash Sakkarai Ravisankar Thiagarajan Duraisamy Muthusamy Manimaran Kuppusamy Muralidhar Moturi Aritra Bera Puthiavan Ramasamy Sivagnanam Shanmugam 《Aquaculture Research》2020,51(5):2112-2124
The selection of aerators and correct numbers can play an essential role in reducing the cost of production in aquaculture. The new generation aerators, namely spiral leaf, air‐jet, submersible and impeller, used in aquaculture, were assessed for its aeration efficiency and energy cost compared with the commonly used paddle wheel aerator. Of the aerators tested, the impeller had the highest aeration efficiency of 2.098 kg O2/kW hr, followed by paddle wheel with 1.436 kg O2/kW hr at 20‰ salinity. The spiral and air‐jet aerators had maximum aeration efficiency of 1.326 and 1.419 kg O2/kW hr, respectively, at 35‰ salinity. The submersible aerator was not efficient as its maximum efficiency was 0.380 kg O2/kW hr. The water flow by paddle wheel was 3 ft/sec and also provides better coverage than other types of aerators. The efficiency of aerators was high in optimum salinities (20‰ and 35‰) than the low or high saline condition. The average energy cost of shrimp pond aeration per hectare was lowest for impeller, followed by paddle wheel aerator. The study provided economic comparisons of vannamei culture using different aeration systems by keeping a uniform set of economic assumptions. Shrimp farms with impellors can give 14%–25% high returns across salinities, whereas spiral leaf can provide 5% high returns at 35‰ salinity. The combination of the type of aerators and the calculated use based on the salinity of the culture systems can result in energy‐saving and also a reduction in the production cost. 相似文献
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Effects of native medicinal herbs (Alternanthera sessilis,Eclipta alba and Cissus quadrangularis) on growth performance,digestive enzymes and biochemical constituents of the monsoon river prawn Macrobrachium malcolmsonii 
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下载免费PDF全文 S. Radhakrishnan P. Saravana Bhavan C. Seenivasan T. Muralisankar R. Shanthi 《Aquaculture Nutrition》2015,21(4):496-506
The medicinal herbs such as Alternanthera sessilis, Eclipta alba and Cissus quadrangularis were used to assess the growth promoting ability, enhancement of muscle biochemical constituents and profiles of amino acid in the freshwater prawn, Macrobrachium malcolmsonii. The herbal powders were separately incorporated with basal diet, and these diets were fed to M. malcolmsonii postlarvae for a period of 90 days. At the end of experiments, the survival of prawn significantly improved in herbal incorporated feed. In addition, the growth parameters, such as weight gain, specific growth rate and protein efficiency rate were significantly (P < 0.05) higher in herbal diets fed groups when compared with control. The activities of digestive enzyme, biochemical constituents, profile of amino acid, energy utilization parameters, concentrations of vitamin C and E were significantly (P < 0.05) elevated in experimental diets fed groups when compared with control. The profiles of essential amino acids were also found elevated in herbal incorporated diets fed PL. Among the three herbs tested, C. quadrangularis incorporated diet fed group showed better performance followed by the E. alba and A. sessilis. The present study suggests that these herbs can be incorporated in artificial feed formulations for Macrobrachium culture. 相似文献
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Ben J Hayes Thomas Gitterle Gopalapillay Gopikrishna Chavali Gopal Gopal Krishna Shrivinas Jahageerdar Carlos Lozano Shankar Alavandi Sivagnanam Paulpandi Pitchaiyappan Ravichandran Morten Rye 《Aquaculture Research》2010,41(11):e872-e877
There has been a highly detrimental impact of the white spot syndrome virus (WSSV) on black tiger shrimp (Penaeus monodon) aquaculture in India. Currently, no cost‐effective measures are available for controlling the disease. One alternative is to improve WSSV resistance through a selective breeding programme for disease‐resistant shrimp, provided that genetic variation exists for this trait. The aim of this study was to evaluate the evidence for genetic variation in resistance to WSSV in P. monodon sourced from Indian populations. Post‐larval shrimp (n=1950) from 54 full‐sibling families were challenged with WSSV using WSSV‐infected mince meat. The heritability was estimated using four different statistical models fitted to the resulting time to death data, including two linear models and two Weibull proportional hazard frailty models. None of the estimated heritabilities were significantly different from zero. We suggest three possible explanations for these results: there actually is very little variation between P. monodon in WSSV resistance and all individuals are highly susceptible to the disease; there is genetic variation in resistance to WSSV in P. monodon but we did not find it in our experiment because the level of challenge in the experiment was too high to allow genetic differences to be expressed; the variation is due to mutations conferring resistance, which are at a low frequency in the population, and we did not sample a broad enough genetic base to capture these mutations. 相似文献
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Growth performance,muscle biochemical constituents,amino acid and fatty acid compositions of the giant freshwater prawn,Macrobrachium rosenbergii,fed with herb‐incorporated diet 下载免费PDF全文
下载免费PDF全文 T. Muralisankar P. Saravana Bhavan S. Radhakrishnan P. Santhanam R. Jayakumar 《Aquaculture Nutrition》2017,23(4):766-776
This study was conducted to evaluate the influence of herbs such as Ocimum sanctum, Phyllanthus amarus and Solanum trilobatum on the freshwater prawn, Macrobrachium rosenbergii, postlarvae (PL). These herbs were powdered and incorporated at 5% with the basal diet separately and in a combination. The M. rosenbergii was fed with these feeds for a period of 90 days. Results indicated that significant (P < 0.05) improvements were observed in the survival, nutritional indices (weight gain, specific growth rate and protein efficiency ratio), proximate muscle biochemical constituents (total protein, amino acid, carbohydrate and lipid), profiles of essential amino acids and fatty acids of prawns fed with herb‐incorporated feeds. Among these herbs supplemented, P. amarus produced significantly (P < 0.05) better performance followed by S. trilobatum and O. sanctum. However, prawns fed with these herbs combination showed an insignificant (P > 0.05) improvement in survival and growth performance when compared to individual supplementation. Hence, this study suggests that the herbs (O. sanctum, P. amarus and S. trilobatum) can be used as a supplementary feed for a sustainable development of freshwater prawn culture. 相似文献
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Maize stalk has become one of the major sources of fibers from the agricultural residues. Use of these fibers as a reinforcement in the polymer is described in this paper. The present work is focused on establishing the properties such as physical, chemical, morphological structure and thermal properties of maize stalk fiber using different characterization techniques. Simple hand layup method was followed for processing the composite material. Chemical treatments of fibers were carried out to study the interaction of fibers with the matrix. The results revealed that maize fibers can also be used as a traditional fiber as reinforcement in a natural fiber reinforced composite materials. 相似文献
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S. Radhakrishnan P. Saravana Bhavan C. Seenivasan R. Shanthi R. Poongodi 《Aquaculture International》2014,22(2):551-572
To assess the growth-promoting potential of three medicinal herbs, Alteranthera sessilis, Eclipta alba and Cissus quadrangularis, a 90-day feeding trial was conducted on Macrobrachium rosenbergii post-larvae (PL) fed with these herb-incorporated feeds. The growth parameters (survival rate, weight gain, specific growth rate and protein efficiency ratio) were significantly (P < 0.05) higher in experimental-diets-fed PL when compared with control. These herbs have acted as appetizer and significantly enhanced the activities of digestive enzymes (protease, amylase and lipase). This in turn significantly (P < 0.05) influenced the parameters of energy utilization (feeding rate, absorption rate, conversion rate, metabolic rate and NH3 excretion rate), which ultimately reflected on significant (P < 0.05) increases in concentrations of biochemical constituents (total protein, amino acid, carbohydrate and lipid, and essential amino acids and unsaturated fatty acids). Therefore, it was believed that synthesis of protein was activated due to the active principles of these herbs and resulted in growth promotion. In this study, the higher (P < 0.05) minerals (Na+ and K+) recorded indicate the fact that their balance was maintained. Similarly, the non-enzymatic antioxidants (vitamin-C and -E) status were also improved significantly (P < 0.05) due to herbal incorporation, which provide additional protection. Further, the haemocytes count and population was also found to be higher (P < 0.05), which ensures prevalence of good host-defence mechanisms in herb-incorporated-feeds-fed PL. Among three herbs tested, C. quadrangularis-incorporated-feed-fed PL showed the best survival, growth and protection as well as production followed by E. alba and A. sessilis. Therefore, these herbs can be incorporated in artificial feed formulations for sustainable development of Macrobrachium culture. 相似文献
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