Search results for: impurity concentration
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 4972

Search results for: impurity concentration

3832 Bioremediation of Polychlorinated Biphenyl (PCBS) Contaminated Soils: A Case Study from Rietvlei Farm at Borehole No. 11, Limpopo Province, South Africa

Authors: D. Sengani, N. Potgieter, P. E. L. Mojapelo

Abstract:

Three bacteria species which comprise of Gram negative and Gram positive microorganisms were isolated and identified on the basis of morpho-cultural study, catalase tests, oxidase tests and biochemical characteristics were found belonging to different genera including Burkholderia cepacia, Pasteurella pneumotropica and Enterococcus faecalis. The main objective of this study was to isolate and identify PCB degrading bacteria from PCB contaminated soils and test them for their degradation ability of PCBs in natural habitat conditions. The results indicated an overall decrease of PCB concentration level with the gradient average ranging from 1.5 to 1.8 respectively. Enterococcus faecalis removed as much as 32% of PCBs in the contaminated soil samples. Whereas Pasteurella pneumotropica could remove 24% of PCBs, Burkholderia cepacia 21% of PCBs and the mixed culture removed 23%. Data showed that the three bacterial strains could tolerate high concentration of PCBs. The results provided the evidence that naturally occurring bacteria in soil contaminated with PCBs have the potential to degrade PCBs. Statistical analysis showed that there was a significant positive correlation between bacteria growth and treatment with a coefficient of (r) =0.1459 and p value < 0.001.

Keywords: bacteria, bioaccumulation, biodegradation, bioremediation, polychlorinated biphenyls

Procedia PDF Downloads 227
3831 Effects of Organic Fertilizer and Azotobacter and Azospirillum Bacteria on Concentration and Composition of Essential Oil of Coriander (Coriandrum Sativum L.)

Authors: M. T. Darzi, M. Shirkhodaei, M. R. Haj Seyed Hadi

Abstract:

The main objective of this study was to determine the effects of organic fertilizer and azotobacter and azospirillum bacteria on concentration and composition of essential oil in the coriander essential oil content, essential oil yield, linalool percent, alpha pinene percent and cymene percent in essential oil. The experiment was carried out as factorial experiment in the base of randomized complete blocks design with eight treatments and three replications at research field of Agriculture Company of Ran in Firouzkuh of iran in 2012. The factors were Vermicompost in four levels (0, 3, 6 and 9 ton/ha) and biofertilizer, mixture of Azotobacter chroococcum and Azospirillum lipoferum in two levels (non-inoculated and inoculated seeds). The present results have shown that vermicompost had significant effects on evaluated traits except linalool percent in essential oil, as the highest essential oil content, essential oil yield and alpha pinene percent in essential were obtained after applying 6 ton/ha vermicompost. The minimum cymene percent in essential oil were obtained after applying 6 ton/ha vermicompost. Biofertilizer also showed significant effects on essential oil yield only. The highest essential oil yield were obtained by using the biofertilizer (inoculated seeds).

Keywords: coriander, vermicompost, biofertilizer, essential oil

Procedia PDF Downloads 296
3830 Spectrophotometric Determination of Photohydroxylated Products of Humic Acid in the Presence of Salicylate Probe

Authors: Julide Hizal Yucesoy, Batuhan Yardimci, Aysem Arda, Resat Apak

Abstract:

Humic substances produce reactive oxygene species such as hydroxyl, phenoxy and superoxide radicals by oxidizing in a wide pH and reduction potential range. Hydroxyl radicals, produced by reducing agents such as antioxidants and/or peroxides, attack on salicylate probe, and form 2,3-dihydroxybenzoate, 2,4-dihydroxybenzoate and 2,5-dihydroxybenzoate species. These species are quantitatively determined by using HPLC Method. Humic substances undergo photodegradation by UV radiation. As a result of their antioxidant properties, they produce hydroxyl radicals. In the presence of salicylate probe, these hydroxyl radicals react with salicylate molecules to form hydroxylated products (dihidroxybenzoate isomers). In this study, humic acid was photodegraded in a photoreactor at 254 nm (400W), formed hydroxyl radicals were caught by salicylate probe. The total concentration of hydroxylated salicylate species was measured by using spectrophotometric CUPRAC Method. And also, using results of time dependent experiments, kinetic of photohydroxylation was determined at different pHs. This method has been applied for the first time to measure the concentration of hydroxylated products. It allows to achieve the results easier than HPLC Method.

Keywords: CUPRAC method, humic acid, photohydroxylation, salicylate probe

Procedia PDF Downloads 190
3829 Physico-Chemical Basis of Thermal Destruction of Benzo(a)Pyrene and Reducing Their Concentration in the Gas Phase

Authors: K. A. Kemelov, Z. K. Maymekov, D. A. Sambaeva, W. Frenzel

Abstract:

Benzo(a)pyrene is widespread carcinogenic and mutagenic environmental pollutant, which is formed in combustion processes of carbonaceous materials at high temperature and still health safety problem related benz(a)pyrene continues to remain actual. At the moment the mechanisms of formation of benzo(a)pyrene are not studied in detail, there is not concrete certain full scheme of synthesis of benzo(a)pyrene. Studies in this area are mainly dedicated to development of measuring tools and chemical reactions analyzes, or to obtain specific evidence of a large group of polycyclic aromatic hydrocarbons (PAHs). Consequently in this study we try to create physical and chemical model of oxidation and thermo destruction processes of benzo(a)pyrene, using critical thermodynamical parameters in order to estimate theoretical derivatives of benzo(a)pyrene and which conditions benzo(a)pyrene degraded into more harmful substances. According to this physical and chemical modeling of thermal destruction process of benzo(a)pyrene in wide ranges of change of temperature value were calculated. C20H12 - H2O-O2 system was taken for modeling of thermal destruction process of benzo(a)pyrene in order to establish distribution range of equilibrium structures and concentrations of molecules in a gas phase. Also technological ways of reduction of concentration of benzo(a)pyrene in a gas phase were supposed.

Keywords: benzo(a)pyrene, emission, PAH, thermodynamic parameters

Procedia PDF Downloads 281
3828 The Extraction and Stripping of Hg(II) from Produced Water via Hollow Fiber Contactor

Authors: Dolapop Sribudda, Ura Pancharoen

Abstract:

The separation of Hg(II) from produced water by hollow fiber contactors (HFC) was investigation. This system included of two hollow fiber modules in the series connecting. The first module used for the extraction reaction and the second module for stripping reaction. Aliquat336 extractant was fed from the organic reservoirs into the shell side of the first hollow fiber module and continuous to the shell side of the second module. The organic liquid was continuously feed recirculate and back to the reservoirs. The feed solution was pumped into the lumen (tube side) of the first hollow fiber module. Simultaneously, the stripping solution was pumped in the same way in tube side of the second module. The feed and stripping solution was fed which had a counter current flow. Samples were kept in the outlet of feed and stripping solution for 1 hour and characterized concentration of Hg(II) by Inductively Couple Plasma Atomic Emission Spectroscopy (ICP-AES). Feed solution was produced water from natural gulf of Thailand. The extractant was Aliquat336 dissolved in kerosene diluent. Stripping solution used was nitric acid (HNO3) and thiourea (NH2CSNH2). The effect of carrier concentration and type of stripping solution were investigated. Results showed that the best condition were 10 % (v/v) Aliquat336 and 1.0 M NH2CSNH2. At the optimum condition, the extraction and stripping of Hg(II) were 98% and 44.2%, respectively.

Keywords: Hg(II), hollow fiber contactor, produced water, wastewater treatment

Procedia PDF Downloads 386
3827 Development of a Framework for Assessing Public Health Risk Due to Pluvial Flooding: A Case Study of Sukhumvit, Bangkok

Authors: Pratima Pokharel

Abstract:

When sewer overflow due to rainfall in urban areas, this leads to public health risks when an individual is exposed to that contaminated floodwater. Nevertheless, it is still unclear the extent to which the infections pose a risk to public health. This study analyzed reported diarrheal cases by month and age in Bangkok, Thailand. The results showed that the cases are reported higher in the wet season than in the dry season. It was also found that in Bangkok, the probability of infection with diarrheal diseases in the wet season is higher for the age group between 15 to 44. However, the probability of infection is highest for kids under 5 years, but they are not influenced by wet weather. Further, this study introduced a vulnerability that leads to health risks from urban flooding. This study has found some vulnerability variables that contribute to health risks from flooding. Thus, for vulnerability analysis, the study has chosen two variables, economic status, and age, that contribute to health risk. Assuming that the people's economic status depends on the types of houses they are living in, the study shows the spatial distribution of economic status in the vulnerability maps. The vulnerability map result shows that people living in Sukhumvit have low vulnerability to health risks with respect to the types of houses they are living in. In addition, from age the probability of infection of diarrhea was analyzed. Moreover, a field survey was carried out to validate the vulnerability of people. It showed that health vulnerability depends on economic status, income level, and education. The result depicts that people with low income and poor living conditions are more vulnerable to health risks. Further, the study also carried out 1D Hydrodynamic Advection-Dispersion modelling with 2-year rainfall events to simulate the dispersion of fecal coliform concentration in the drainage network as well as 1D/2D Hydrodynamic model to simulate the overland flow. The 1D result represents higher concentrations for dry weather flows and a large dilution of concentration on the commencement of a rainfall event, resulting in a drop of the concentration due to runoff generated after rainfall, whereas the model produced flood depth, flood duration, and fecal coliform concentration maps, which were transferred to ArcGIS to produce hazard and risk maps. In addition, the study also simulates the 5-year and 10-year rainfall simulations to show the variation in health hazards and risks. It was found that even though the hazard coverage is very high with a 10-year rainfall events among three rainfall events, the risk was observed to be the same with a 5-year and 10-year rainfall events.

Keywords: urban flooding, risk, hazard, vulnerability, health risk, framework

Procedia PDF Downloads 57
3826 Optimization of Sucrose Concentration, PH Level and Inoculum Size for Callus Proliferation and Anti-bacterial Potential of Stevia Rebaudiana Bertoni

Authors: Inayat Ur Rahman Arshad

Abstract:

Stevia rebaudiana B. is a shrubby perennial herb of Asteraceae family that possesses the unique ability of accumulative non caloric sweet Steviol Glycosides (SGs). The purpose of the study is to optimize sugar concentration, pH level and inoculum size for inducing the callus with optimum growth and efficient antibacterial potential. Three different experiments were conducted in which Callus explant from three-months-old already established callus of Stevia reabudiana of four different sizes were inoculated on Murashige and Skoog (MS) basal medium supplemented with five different sucrose concentration and pH adjusted at four different levels. Maximum callus induction 100, 87.5 and 85.33% was resulted in the medium supplemented with 30g/l sucrose, pH maintained at 5.5 and inoculated with 1.25g inoculum respectively. Similarly, the highest fresh weight 65.00, 75.50 and 50.53g/l were noted in medium fortified with 40g/l sucrose, inoculated 1.25g inoculum and 6.0 pH level respectively. However, the callus developed in medium containing 50g/l sucrose found highly antibacterial potent with 27.3 and 26.5mm inhibition zone against P. vulgaris and B. subtilize respectively. Similarly, the callus grown on medium inoculated with 1.00g inoculum resulted in maximum antibacterial potential against S. aureus and P. vulgaris with 25 and 23.72mm inhibition zones respectively. However, in the case of pH levels the medium maintained at 6.5pH showed maximum antibacterial activity against P. vulgaris, B.subtilis and E.coli with 27.9, 25 and 23.72mm respectively. The ethyl acetate extract of Stevia callus and leaves did not show antibacterial potential against Xanthomonas campestris and Clavebactor michiganensis. In the entire experiment the standard antibacterial agent Streptomycin showed the highest inhibition zones from the rest of the callus extract, however the pure DMSO (Dimethyl Sulfoxide) caused no inhibitory zone against any bacteria. From these findings it is concluded that among various levels sucrose at the rate of 40g L-1, pH 6.0 and inoculums 0.75g was found best for most of the growth and quality attributes including fresh weight, dry weight and antibacterial activities and therefore can be recommended for callus proliferation and antibacterial potential of Stevia rebaudiana

Keywords: Steviol Glycosides, Skoog, Murashige, Clavebactor michiganensis

Procedia PDF Downloads 73
3825 Evaluation of Nanoparticle Application to Control Formation Damage in Porous Media: Laboratory and Mathematical Modelling

Authors: Gabriel Malgaresi, Sara Borazjani, Hadi Madani, Pavel Bedrikovetsky

Abstract:

Suspension-Colloidal flow in porous media occurs in numerous engineering fields, such as industrial water treatment, the disposal of industrial wastes into aquifers with the propagation of contaminants and low salinity water injection into petroleum reservoirs. The main effects are particle mobilization and captured by the porous rock, which can cause pore plugging and permeability reduction which is known as formation damage. Various factors such as fluid salinity, pH, temperature, and rock properties affect particle detachment. Formation damage is unfavorable specifically near injection and production wells. One way to control formation damage is pre-treatment of the rock with nanoparticles. Adsorption of nanoparticles on fines and rock surfaces alters zeta-potential of the surfaces and enhances the attachment force between the rock and fine particles. The main objective of this study is to develop a two-stage mathematical model for (1) flow and adsorption of nanoparticles on the rock in the pre-treatment stage and (2) fines migration and permeability reduction during the water production after the pre-treatment. The model accounts for adsorption and desorption of nanoparticles, fines migration, and kinetics of particle capture. The system of equations allows for the exact solution. The non-self-similar wave-interaction problem was solved by the Method of Characteristics. The analytical model is new in two ways: First, it accounts for the specific boundary and initial condition describing the injection of nanoparticle and production from the pre-treated porous media; second, it contains the effect of nanoparticle sorption hysteresis. The derived analytical model contains explicit formulae for the concentration fronts along with pressure drop. The solution is used to determine the optimal injection concentration of nanoparticle to avoid formation damage. The mathematical model was validated via an innovative laboratory program. The laboratory study includes two sets of core-flood experiments: (1) production of water without nanoparticle pre-treatment; (2) pre-treatment of a similar core with nanoparticles followed by water production. Positively-charged Alumina nanoparticles with the average particle size of 100 nm were used for the rock pre-treatment. The core was saturated with the nanoparticles and then flushed with low salinity water; pressure drop across the core and the outlet fine concentration was monitored and used for model validation. The results of the analytical modeling showed a significant reduction in the fine outlet concentration and formation damage. This observation was in great agreement with the results of core-flood data. The exact solution accurately describes fines particle breakthroughs and evaluates the positive effect of nanoparticles in formation damage. We show that the adsorbed concentration of nanoparticle highly affects the permeability of the porous media. For the laboratory case presented, the reduction of permeability after 1 PVI production in the pre-treated scenario is 50% lower than the reference case. The main outcome of this study is to provide a validated mathematical model to evaluate the effect of nanoparticles on formation damage.

Keywords: nano-particles, formation damage, permeability, fines migration

Procedia PDF Downloads 602
3824 Optimization of Sucrose Concentration, pH Level and Inoculum Size for Callus Proliferation and Anti-Bacterial Potential of Stevia rebaudiana Bertoni

Authors: Inayat Ur Rahman Arshad

Abstract:

Background: Stevia rebaudiana B. is a shrubby perennial herb of Asteraceae family that possesses the unique ability of accumulative non-caloric sweet steviol glycosides (SGs). Purpose: The purpose of the study is to optimize sugar concentration, pH level, and inoculum size for inducing the callus with optimum growth and efficient antibacterial potential. Method: Three different experiments were conducted in which Callus explant from three-months-old already established callus of Stevia reabudiana of four different sizes was inoculated on Murashige and Skoog (MS) basal medium supplemented with five different sucrose concentration and pH adjusted at four different levels. Results: Maximum callus induction 100, 87.5, and 85.33% resulted in the medium supplemented with 30 g/l sucrose, pH maintained at 5.5, and inoculated with 1.25g inoculum, respectively. Similarly, the highest fresh weights 65.00, 75.50, and 50.53 g/l were noted in a medium fortified with 40 g/l sucrose, inoculated 1.25g inoculum, and 6.0 pH level, respectively. However, the callus developed in a medium containing 50 g/l sucrose was found to be highly antibacterial potent with 27.3 and 26.5 mm inhibition zone against P. vulgaris and B. subtilis, respectively. Similarly, the callus grown on a medium inoculated with 1.00 g inoculum resulted in maximum antibacterial potential against S. aureus and P. vulgaris with 25 and 23.72 mm inhibition zone, respectively. However, in the case of pH levels, the medium maintained at 6.5 pH showed maximum antibacterial activity against P. vulgaris, B.subtilis, and E.coli with 27.9, 25, and 23.72 mm, respectively. The ethyl acetate extract of Stevia callus and leaves did not show antibacterial potential against Xanthomonas campestris and Clavebactor michiganensis. In the entire experiment, the standard antibacterial agent Streptomycin showed the highest inhibition zones among the rest of the callus extract; however, the pure dimethyl sulfoxide (DMSO) caused no inhibitory zone against any bacteria. Conclusion: From these findings, it is concluded that among various levels, sucrose @ 40 g L⁻¹, pH 6.0, and inoculums at 0.75 g were found best for most of the growth and quality attributes, including fresh weight, dry weight, and antibacterial activities and therefore can be recommended for callus proliferation and antibacterial potential of Stevia rebaudiana.

Keywords: Stevia rebaudiana, Steviol Glycosides, callus, Xanthomonas campestris

Procedia PDF Downloads 68
3823 The Effect of Excess Sulphur on Najdi Sheep

Authors: Fatima Al-Humaid

Abstract:

This research work was done to investigate the cause of paralysis in Najdi lambs born in certain farms where the drinking water and diet contained high concentrations of sulphur. The drinking water in these farms was obtained from deep bore wells drilled in the farm. The lambs developed paralysis of the hind limbs at the age of 4-6 weeks and their condition deteriorated continuously until they finally died. The appetite and suckling ability remained good throughout the course of the disease but when the lambs were completely unable to move and reach for the udder, feed and water they died. Postmortem examination of the brain of paralyzed lambs showed that it was liquefied. When the brain was examined histologically, a liquefactive necrosis was seen in the form of cavities in the nervous tissue. Similar histologic picture was seen in the spinal cord of the affected lambs. Analysis for the mineral content of the fodder showed that the concentration of sulphur was 21.6 3.4 g/kg DM which is considered very high for the nutrition of sheep. Analysis for the concentration of copper and selenium in the feed showed that the concentrations of both were normal. This excluded diseases such as swayback which is caused by copper deficiency and white muscle disease, which caused by selenium deficiency. Both of these two last diseases are characterized by paralysis of lambs.

Keywords: brain histology, sulphur poisoning, Najdi sheep, veterinary medicine

Procedia PDF Downloads 587
3822 Effect of Microfiltration on the Composition and Ripening of Iranian Fetta Cheese

Authors: M. Dezyani, R. Ezzati belvirdi, M. Shakerian, H. Mirzaei

Abstract:

The effect of Microfiltration (MF) on proteolysis, hardness, and flavor of Feta cheese during 6 mo of aging was determined. Raw skim milk was microfiltered two-fold in two cheese making trials. In trial 1, four vats of cheese were made in 1 d using unconcentrated milk (1X), 1.26X, 1.51X, and 1.82X Concentration Factors (CF). Casein-(CN)-to-fat ratio was constant among treatments. Proteolysis during cheese aging decreased with increasing CF due to either limitation of substrate availability for chymosin due to low moisture in the nonfat substance (MNFS), inhibition of chymosin activity by high molecular weight milk serum proteins, such as α2-macroglobulin, retained in the cheese or low residual chymosin in the cheese. Hardness of fresh cheese increased, and cheese flavor intensity decreased with increasing CF. In trial 2, the 1X and 1.8X CF were compared directly. Changes made in the cheese making procedure for the 1.8X CF (more chymosin and less cooking) increased the MNFS and made proteolysis during aging more comparable for the 1X and 1.8X cheeses. The significant difference in cheese hardness due to CF in trial 1 was eliminated in trial 2. In a triangle test, panelists could not differentiate between the 1X and 1.8X cheeses. Therefore, increasing chymosin and making the composition of the two cheeses more similar allowed production of aged Fetta cheese from milk concentrated up to 1.8X by MF that was not perceived as different from aged feta cheese produced without MF.

Keywords: feta cheese, microfiltration, concentration factor, proteolysis

Procedia PDF Downloads 398
3821 Evaluation Of In Vitro Antioxidant Potential of Camellia Sinensis Leaves Extract

Authors: Jirathan Pongchababnapa

Abstract:

Polyphenols are the most common antioxidant found in plants and are efficient in capturing oxidative free radicals. Antioxidants are substances found in medicinal plants which may have a protective role to play in certain conditions such as heart disease, stroke and some cancers. By relying on these benefits, we have traced out the presence of antioxidant in Camellia sinensis leaves extract. This study aims to evaluate flavonoids content in C. sinensisextract and investigate antioxidant activities by using DPPH and ABTS radical scavenging capacity assay. The total flavonoid content of C. Sinensis extract was determined and expressed as quercetin equivalents (QE)/g measured by the aluminum chloride colorimetric method. The results showed that the IC₅₀ of C. Sinensis leaves extract were 40.90 μg/mL ± 0.755 and32.96 μg/mL ± 0.679 for DPPH and ABTS, respectively. C. Sinensis extract at increasing concentration showed antioxidant activities as a concentration dependent manner. In the DPPH assay, vitamin C was used as a positive control, whereas Trolox was used as a positive control in the ABTS assay. In conclusion, C. Sinensis extract consisted of a high amount of flavonoids content which possesses potent antioxidant activity. However, further investigation on the identification of pure compound of this plant and molecular antioxidant assays are still required.

Keywords: ABTS assay, antioxidant, camellia sinensis, DPPH assay, total flavonoid content

Procedia PDF Downloads 190
3820 The Effect of Yb3+ Concentration on Spectroscopic properties of Strontium Cerate Doped with Tm3+ and Yb3+

Authors: Yeon Woo Seo, Haeyoung Choi, Jung Hyun Jeong

Abstract:

Recently, the UC phosphors have attracted much attention owing to their wide applicability in areas such as biological fluorescence labeling, three-dimensional color displays, temperature sensor, solar cells, white light emitting diodes (WLEDs), fiber optic communication, anti-counterfeiting and other areas. The UC efficiency is mainly dependent on the host lattice and the interaction between the host lattice and doped ions. Up to date, various host matrices, such as oxides, fluorides, vanadates and phosphates, have been investigated as efficient UC luminescent hosts. Recently, oxide materials with low phonon energy have been investigated as the host matrices of UC materials due to their high chemical durability and physical stability. A series of Sr2CeO4: Tm3+/Yb3+ phosphors with different concentrations of Yb3+ ions have been successfully prepared using the high-energy ball milling method. In this study, we reported the UC luminescent properties of Tm3+/Yb3+ ions co-doped Sr2CeO4 phosphors under an excitation wavelength of 975 nm. Furthermore, the structural and morphological characteristics, as well as the UC luminescence mechanism were investigated in detail. The X-ray diffraction patterns confirmed their orthorhombic structure. Under 975 nm excitation, the emission peaks were observed at 478 nm (blue) and 652 nm (red), corresponding to the 1G4 → 3H6 and 1G4 → 3F4 transitions of Tm3+, respectively. The optimized doping concentration of Yb3+ ion was 10 mol%.

Keywords: Strontium Cerate, up-conversion, luminescence, Tm3+, Yb3+

Procedia PDF Downloads 248
3819 Biological Activity of Bilberry Pomace

Authors: Gordana S. Ćetković, Vesna T. Tumbas Šaponjac, Sonja M. Djilas, Jasna M. Čanadanović-Brunet, Sladjana M. Stajčić, Jelena J. Vulić

Abstract:

Bilberry is one of the most important dietary sources of phenolic compounds, including anthocyanins, phenolic acids, flavonol glycosides and flavan-3-ols. These phytochemicals have different biological activities and therefore may improve our health condition. Also, anthocyanins are interesting to the food industry as colourants. In the present study, bilberry pomace, a by-product of juice processing, was used as a potential source of bioactive compounds. The contents of total phenolic acids, flavonoids and anthocyanins in bilberry pomace were determined by HPLC/UV-Vis. The biological activities of bilberry pomace were evaluated by reducing power (RP) and α-glucosidase inhibitory potential (α-GIP), and expressed as RP0.5 value (the effective concentration of bilberry pomace extract assigned at 0.5 value of absorption) and IC50 value (the concentration of bilberry pomace extract necessary to inhibit 50% of α-glucosidase enzyme activity). Total phenolic acids content was 807.12 ± 25.16 mg/100 g pomace, flavonoids 54.36 ± 1.83mg/100 g pomace and anthocyanins 3426.18 ± 112.09 mg/100 g pomace. The RP0.5 value of bilberry pomace was 0.38 ± 0.02 mg/ml, while IC50 value was 1.82 ± 0.11 mg/ml. These results have revealed the potential for valorization of bilberry juice production by-products for further industrial use as a rich source of bioactive compounds and natural colourants (mainly anthocyanins).

Keywords: bilberry pomace, phenolics, antioxidant activity, reducing power, α-glucosidase enzyme activity

Procedia PDF Downloads 580
3818 Effect of Chemical Concentration on the Rheology of Inks for Inkjet Printing

Authors: M. G. Tadesse, J. Yu, Y. Chen, L. Wang, V. Nierstrasz, C. Loghin

Abstract:

Viscosity and surface tension are the fundamental rheological property of an ink for inkjet printing. In this work, we optimized the viscosity and surface tension of inkjet inks by varying the concentration of glycerol with water, PEDOT:PSS with glycerol and water, finally by adding the surfactant. The surface resistance of the sample was characterized by four-probe measurement principle. The change in volume of PEDOT:PSS in water, as well as the change in weight of glycerol in water has got a great influence on the viscosity on both temperature dependence and shear dependence behavior of the ink solution. The surface tension of the solution changed from 37 to 28 mN/m due to the addition of Triton. Varying the volume of PEDOT:PSS and the volume of glycerol in water has a great influence on the viscosity of the ink solution for inkjet printing. Viscosity drops from 12.5 to 9.5 mPa s with the addition of Triton at 25 oC. The PEDOT:PSS solution was found to be temperature dependence but not shear dependence as it is a Newtonian fluid. The sample was used to connect the light emitting diode (LED), and hence the electrical conductivity, with a surface resistance of 0.158 KΩ/square, was sufficient enough to give transfer current for LED lamp. The rheology of the inkjet ink is very critical for the successful droplet formation of the inkjet printing.

Keywords: shear rate, surface tension, surfactant, viscosity

Procedia PDF Downloads 160
3817 Spray Drying and Physico-Chemical Microbiological Evaluation of Ethanolic Extracts of Propolis

Authors: David Guillermo Piedrahita Marquez, Hector Suarez Mahecha, Jairo Humberto Lopez

Abstract:

The propolis are substances obtained from the beehive have an action against pathogens, prooxidant substances and free radicals because of its polyphenols content, this has motivated the use of these compounds in the food and pharmaceutical industries. However, due to their organoleptic properties and their ability to react with other compounds, their application has been limited; therefore, the objective of this research was to propose a mechanism to protect propolis and mitigate side effects granted by its components. To achieve the stated purpose ethanolic extracts of propolis (EEP) from three samples from Santander were obtained and their antioxidant and antimicrobial activity were evaluated in order to choose the extract with the biggest potential. Subsequently mixtures of the extract with maltodextrin were prepared by spray drying varying concentration and temperature, finally the yield, the physicochemical, and antioxidant properties of the products were measured. It was concluded that Socorro propolis was the best for the production of microencapsulated due to their activity against pathogenic strains, for its large percentage of DPPH radical inactivation and for its high phenolic content. In spray drying, the concentration of bioactive had a greater impact than temperature and the conditions set allowed a good performance and the production of particles with high antioxidant potential and little chance of proliferation of microorganisms. Also, it was concluded that the best conditions that allowed us to obtain the best particles were obtained after drying a mixture 1:2 ( EEP: Maltodextrin), besides the concentration is the most important variable in the spray drying process, at the end we obtained particles of different sizes and shape and the uniformity of the surface depend on the temperature. After watching the previously mentioned microparticles by scanning electron microscopy (SEM) it was concluded that most of the particles produced during the spray dry process had a spherical shape and presented agglomerations due to the moisture content of the ethanolic extracts of propolis (EEP), the morphology of the microparticles contributed to the stability of the final product and reduce the loss of total phenolic content.

Keywords: spray drying, propolis, maltodextrin, encapsulation, scanning electron microscopy

Procedia PDF Downloads 274
3816 Antimicrobial Activity of Ilex paraguariensis Sub-Fractions after Liquid-Liquid Partitioning

Authors: Sabah El-Sawalhi, Elie Fayad, Roula M. Abdel-Massih

Abstract:

Ilex paraguariensis (Yerba Mate) is a medium to large tree commonly consumed by South Americans. Its leaves and stems are associated with different biological activities. The purpose of this study was to evaluate the antibacterial activity of Yerba Mate against Gram-positive and Gram-negative bacterial strains and its action against some resistant bacteria with different resistance profiles. Yerba Mate aqueous extracts were prepared at 70°C for 2 hrs, and the microdilution method was used to determine the minimum inhibitory concentration (MIC). Gram-positive bacteria exhibited a stronger antibacterial activity (MIC ranged between 0.468 mg/mL and 15 mg/mL) than Gram-negative bacteria. Yerba Mate was also extracted with acetone: water (1:1) and then further sub-fractionated with hexane, chloroform, and ethyl acetate. MIC values against Staphylococcus aureus ranged from 0.78 to 2.5 mg/ml for the chloroform fraction, from 1.56 to 3.75 mg/ml for the ethyl acetate fraction, and 0.78 to 1.87 mg/ml for the water fraction. The water fraction also exhibited antibacterial activity against Salmonella species (MIC ranged from 1.56 mg/ml to 3.12 mg/ml). The water fraction exhibited the highest antibacterial activity among all the fractions obtained. More studies are needed to determine the molecule or molecules responsible for this activity.

Keywords: antibacterial activity, bacterial resistance, minimum inhibitory concentration, yerba mate

Procedia PDF Downloads 120
3815 Evaluation of Collagen Synthesis in Macrophages/Fibroblasts Co-Culture Using Polylactic Acid Particles as Stimulants

Authors: Feng Ju Chuang, Yu Wen Wang, Tai Jung Hsieh, Shyh Ming Kuo

Abstract:

Polylactic acid is a synthetic polymer with good biocompatibility and degradability, is widely used in clinical applications. In this study, we utilized Polylactic acid particles as stimulants for macrophages and the collagen synthesis of co-cultured fibroblasts was evaluated. The results indicated that Polylactic acid particles were nontoxic to cells from 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. No obvious inflammation effect was observed (under the PLLA concentration of 1 mg/mL) after 24-h co-culture of Raw264.7 and NIH3T3 cells (from TNF-α assay). The addition of PLLA particles to the Raw264.7 and NIH3T3 co-cultures increased the synthesis of collagen, the highest collagen synthesis from the fibroblast was the 0.2 mg/mL (approximately 60% increased as compared with without addition Polylactic acid particles). Moreover, a co-axial atomization delivery device was used to percutaneously introduce Polylactic acid particles into the dermis layer and stimulating macrophages to secrete growth factors promoting fibroblasts to produce collagen. The preliminary results demonstrated the synthesis of collagen was increased mildly after the introduction of Polylactic acid particles for 28-d post implantation. The Polylactic acid particles could be successfully introduced into the dermis layer from H&E staining examination, however, the optimum concentration of Polylactic acid particles and the time-period for collagen synthesis still need to be evaluated.

Keywords: collagen synthesis, macrophage, NIH3T3 cells, polylactic acid particles

Procedia PDF Downloads 91
3814 Effect of pH-Dependent Surface Charge on the Electroosmotic Flow through Nanochannel

Authors: Partha P. Gopmandal, Somnath Bhattacharyya, Naren Bag

Abstract:

In this article, we have studied the effect of pH-regulated surface charge on the electroosmotic flow (EOF) through nanochannel filled with binary symmetric electrolyte solution. The channel wall possesses either an acidic or a basic functional group. Going beyond the widely employed Debye-Huckel linearization, we develop a mathematical model based on Nernst-Planck equation for the charged species, Poisson equation for the induced potential, Stokes equation for fluid flow. A finite volume based numerical algorithm is adopted to study the effect of key parameters on the EOF. We have computed the coupled governing equations through the finite volume method and our results found to be in good agreement with the analytical solution obtained from the corresponding linear model based on low surface charge condition or strong electrolyte solution. The influence of the surface charge density, reaction constant of the functional groups, bulk pH, and concentration of the electrolyte solution on the overall flow rate is studied extensively. We find the effect of surface charge diminishes with the increase in electrolyte concentration. In addition for strong electrolyte, the surface charge becomes independent of pH due to complete dissociation of the functional groups.

Keywords: electroosmosis, finite volume method, functional group, surface charge

Procedia PDF Downloads 401
3813 Investigating the Process Kinetics and Nitrogen Gas Production in Anammox Hybrid Reactor with Special Emphasis on the Role of Filter Media

Authors: Swati Tomar, Sunil Kumar Gupta

Abstract:

Anammox is a novel and promising technology that has changed the traditional concept of biological nitrogen removal. The process facilitates direct oxidation of ammonical nitrogen under anaerobic conditions with nitrite as an electron acceptor without the addition of external carbon sources. The present study investigated the feasibility of anammox hybrid reactor (AHR) combining the dual advantages of suspended and attached growth media for biodegradation of ammonical nitrogen in wastewater. The experimental unit consisted of 4 nos. of 5L capacity AHR inoculated with mixed seed culture containing anoxic and activated sludge (1:1). The process was established by feeding the reactors with synthetic wastewater containing NH4-H and NO2-N in the ratio 1:1 at HRT (hydraulic retention time) of 1 day. The reactors were gradually acclimated to higher ammonium concentration till it attained pseudo steady state removal at a total nitrogen concentration of 1200 mg/l. During this period, the performance of the AHR was monitored at twelve different HRTs varying from 0.25-3.0 d with increasing NLR from 0.4 to 4.8 kg N/m3d. AHR demonstrated significantly higher nitrogen removal (95.1%) at optimal HRT of 1 day. Filter media in AHR contributed an additional 27.2% ammonium removal in addition to 72% reduction in the sludge washout rate. This may be attributed to the functional mechanism of filter media which acts as a mechanical sieve and reduces the sludge washout rate many folds. This enhances the biomass retention capacity of the reactor by 25%, which is the key parameter for successful operation of high rate bioreactors. The effluent nitrate concentration, which is one of the bottlenecks of anammox process was also minimised significantly (42.3-52.3 mg/L). Process kinetics was evaluated using first order and Grau-second order models. The first-order substrate removal rate constant was found as 13.0 d-1. Model validation revealed that Grau second order model was more precise and predicted effluent nitrogen concentration with least error (1.84±10%). A new mathematical model based on mass balance was developed to predict N2 gas in AHR. The mass balance model derived from total nitrogen dictated significantly higher correlation (R2=0.986) and predicted N2 gas with least error of precision (0.12±8.49%). SEM study of biomass indicated the presence of the heterogeneous population of cocci and rod shaped bacteria of average diameter varying from 1.2-1.5 mm. Owing to enhanced NRE coupled with meagre production of effluent nitrate and its ability to retain high biomass, AHR proved to be the most competitive reactor configuration for dealing with nitrogen laden wastewater.

Keywords: anammox, filter media, kinetics, nitrogen removal

Procedia PDF Downloads 370
3812 Optimization of Parameters for Electrospinning of Pan Nanofibers by Taguchi Method

Authors: Gamze Karanfil Celep, Kevser Dincer

Abstract:

The effects of polymer concentration and electrospinning process parameters on the average diameters of electrospun polyacrylonitrile (PAN) nanofibers were experimentally investigated. Besides, mechanical and thermal properties of PAN nanofibers were examined by tensile test and thermogravimetric analysis (TGA), respectively. For this purpose, the polymer concentration, solution feed rate, supply voltage and tip-to-collector distance were determined as the control factors. To succeed these aims, Taguchi’s L16 orthogonal design (4 parameters, 4 level) was employed for the experimental design. Optimal electrospinning conditions were defined using the signal-to-noise (S/N) ratio that was calculated from diameters of the electrospun PAN nanofibers according to "the-smaller-the-better" approachment. In addition, analysis of variance (ANOVA) was evaluated to conclude the statistical significance of the process parameters. The smallest diameter of PAN nanofibers was observed. According to the S/N ratio response results, the most effective parameter on finding out of nanofiber diameter was determined. Finally, the Taguchi design of experiments method has been found to be an effective method to statistically optimize the critical electrospinning parameters used in nanofiber production. After determining the optimum process parameters of nanofiber production, electrical conductivity and fuel cell performance of electrospun PAN nanofibers on the carbon papers will be evaluated.

Keywords: nanofiber, electrospinning, polyacrylonitrile, Taguchi method

Procedia PDF Downloads 191
3811 Malate Dehydrogenase Enabled ZnO Nanowires as an Optical Tool for Malic Acid Detection in Horticultural Products

Authors: Rana Tabassum, Ravi Kant, Banshi D. Gupta

Abstract:

Malic acid is an extensively distributed organic acid in numerous horticultural products in minute amounts which significantly contributes towards taste determination by balancing sugar and acid fractions. An enhanced concentration of malic acid is utilized as an indicator of fruit maturity. In addition, malic acid is also a crucial constituent of several cosmetics and pharmaceutical products. An efficient detection and quantification protocol for malic acid is thus highly demanded. In this study, we report a novel detection scheme for malic acid by synergistically collaborating fiber optic surface plasmon resonance (FOSPR) and distinctive features of nanomaterials favorable for sensing applications. The design blueprint involves the deposition of an assembly of malate dehydrogenase enzyme entrapped in ZnO nanowires forming the sensing route over silver coated central unclad core region of an optical fiber. The formation and subsequent decomposition of the enzyme-analyte complex on exposure of the sensing layer to malic acid solutions of diverse concentration results in modification of the dielectric function of the sensing layer which is manifested in terms of shift in resonance wavelength. Optimization of experimental variables such as enzyme concentration entrapped in ZnO nanowires, dip time of probe for deposition of sensing layer and working pH range of the sensing probe have been accomplished through SPR measurements. The optimized sensing probe displays high sensitivity, broad working range and a minimum limit of detection value and has been successfully tested for malic acid determination in real samples of fruit juices. The current work presents a novel perspective towards malic acid determination as the unique and cooperative combination of FOSPR and nanomaterials provides myriad advantages such as enhanced sensitivity, specificity, compactness together with the possibility of online monitoring and remote sensing.

Keywords: surface plasmon resonance, optical fiber, sensor, malic acid

Procedia PDF Downloads 364
3810 Cellular Energy Metabolism Decreases with Age in the Trophocytes and Oenocytes of Honeybees (Apis Mellifera)

Authors: Chin-Yuan Hsu, Yu-Lung Chuang

Abstract:

The expression, concentration, and activity of mitochondrial energy-utilized molecules and cellular energy-regulated molecules decreased with age in the trophocytes and oenocytes of honeybees (Apis mellifera), but those of cellular energy-metabolized molecules is unknown. In this study, the expression, concentration, and activity of cellular energy-metabolized molecules were assayed in the trophocytes and fat cells of young and old worker bees by using the techniques of cell and biochemistry. The results showed that (i) the •-hydroxylacyl-coenzyme A dehydrogenase (HOAD) activity/citrate synthase (CS) activity ratio, non-esterified fatty acids concentrations, the expression of eukaryotic initiation factor 4E, and the expression of phosphorylated eIF4E binding protein 1 decreased with age; (ii) fat and glycogen accumulation increased with age; and (iii) the pyruvate dehydrogenase (PDH) activity/citrate synthase (CS) activity ratio was not correlated with age. These finding indicated that •-oxidation (HOAD/CS) and protein synthsis decreased with age. Glycolysis (PDH/CS) was unchanged with age. The most likely reason is that sugars are the vital food of worker bees. Taken together these data reveal that young workers have higher cellular energy metabolism than old workers and that aging results in a decline in the cellular energy metabolism in worker honeybees.

Keywords: aging, energy, honeybee, metabolism

Procedia PDF Downloads 455
3809 The Effect of Four Local Plant Extract on the Control of Rice Weevil, Sitophilus oryzae L.

Authors: Banaz Sdiq Abdulla

Abstract:

Four local species (Allium sativum, Capsicum annum, Anethum graveolens, and Ocimum basilicum) were evaluated in the laboratory of Biolog Department, College of Education, for their ability to protect stored rice from the infection by weevil Sitophilus oryzae. Aqueous extracts of the plant species were applied as direct admixture of three concentrations levels of 1%, 2.5%, and 5% (W/V) to assess for mortality, adult emergence, and repellency and weight losses. The results showed that Al. sativum extracts was the most effective as it gave the highest mortality (90%)at 5% concentration followed by Capsicum annum (80%) on the 4th day post treatment, the result showed that the plant extract of different concentrations exhibited different level of reduction in adult emergence and different repellency of adults of Sitophilus oryzae. Allium sativum recorded the lowest mean number of adult emergence (8) followed by Capsicum annum (10) at 5% concentration, while Capsicum annum was found to be revealed complete repellent agent (100%) repellency on the 6th hours against Sitophilus oryzae followed by Allium sativum and Anethum graveolens (81.8%). There was a significant (P>0.05) reduction in the weight lossed by the weevils with less damaged recorded on grain treated with Allium sativum and Capsicum annum (1.6%) and (2.3%) respectively.

Keywords: plant extraction, rice, protectant, pest

Procedia PDF Downloads 416
3808 Reverse Impact of Temperature as Climate Factor on Milk Production in ChaharMahal and Bakhtiari

Authors: V. Jafari, M. Jafari

Abstract:

When long-term changes in normal weather patterns happen in a certain area, it generally could be identified as climate change. Concentration of principal's greenhouse gases such as carbon dioxide, nitrous oxide, methane, ozone, and water vapor will cause climate change and perhaps climate variability. Main climate factors are temperature, precipitation, air pressure, and humidity. Extreme events may be the result of the changing of carbon dioxide concentration levels in the atmosphere which cause a change in temperature. Extreme events in some ways will affect the productivity of crop and dairy livestock. In this research, the correlation of milk production and temperature as the main climate factor in ChaharMahal and Bakhtiari province in Iran has been considered. The methodology employed for this study consists, collect reports and published national and provincial data, available recorded data on climate factors and analyzing collected data using statistical software. Milk production in ChaharMahal and Bakhtiari province is in the same pattern as national milk production in Iran. According to the current study results, there is a significant negative correlation between milk production in ChaharMahal and Bakhtiari provinces and temperature as the main climate change factor.

Keywords: Chaharmahal and Bakhtiari, climate change, impacts, Iran, milk production

Procedia PDF Downloads 143
3807 Development of Non-Point Pollutants Removal Equipments Using Media with Bacillus sp.

Authors: Han-Seul Lee, Min-Koo Kang, Sang-Ill Lee

Abstract:

This study was conducted to reduce runoff by rainwater infiltration facility using attached growth with Bacillus sp., which are reported to remove nitrogen and phosphorus, as well as organic matter effectively. This study was investigated non-point pollutants removal efficiency of organic, nitrogen, and phosphorus in column using the media attached growth with Bacillus sp. To compare attached growth with bacillus sp. and detached media, two columns filled with perlite, zeolite, vermiculite, pumice, peat-moss was installed. In A column (attached growth with bacillus sp.), in case of infiltration velocity 30 mm/hr in high concentration of influent, it showed the removal efficiency (after aging term) is SS (suspended solid) 85.8±1.2 %, T-P (total phosphorus) 67.0±8.1 %, T-N (total nitrogen) 66.0±4.9 %, COD (chemical oxygen demand) 73.6±2.9 %, NH4+-N 72.7±3.0 %. In B column (detached media), in case of infiltration velocity 30 mm/hr in high concentration of influent, it showed the removal efficiency (after aging term) is SS 86.0±2.2 %, T-P 62.5±11.3 %, T-N 53.3±3.9 %, COD 34.6±3.7 %, NH4+-N 61.5±2.8 %. Removal efficiency of A column is better than B column. As the result from this study, using media with Bacillus sp. can improve an effective removal of non-point source pollutants.

Keywords: non-point source pollutants, Bacillus sp., rainwater, infiltration facility

Procedia PDF Downloads 310
3806 The Impact of HKUST-1 Metal-Organic Framework Pretreatment on Dynamic Acetaldehyde Adsorption

Authors: M. François, L. Sigot, C. Vallières

Abstract:

Volatile Organic Compounds (VOCs) are a real health issue, particularly in domestic indoor environments. Among these VOCs, acetaldehyde is frequently monitored in dwellings ‘air, especially due to smoking and spontaneous emissions from the new wall and soil coverings. It is responsible for respiratory complaints and is classified as possibly carcinogenic to humans. Adsorption processes are commonly used to remove VOCs from the air. Metal-Organic Frameworks (MOFs) are a promising type of material for high adsorption performance. These hybrid porous materials composed of metal inorganic clusters and organic ligands are interesting thanks to their high porosity and surface area. The HKUST-1 (also referred to as MOF-199) is a copper-based MOF with the formula [Cu₃(BTC)₂(H₂O)₃]n (BTC = benzene-1,3,5-tricarboxylate) and exhibits unsaturated metal sites that can be attractive sites for adsorption. The objective of this study is to investigate the impact of HKUST-1 pretreatment on acetaldehyde adsorption. Thus, dynamic adsorption experiments were conducted in 1 cm diameter glass column packed with 2 cm MOF bed height. MOF were sieved to 630 µm - 1 mm. The feed gas (Co = 460 ppmv ± 5 ppmv) was obtained by diluting a 1000 ppmv acetaldehyde gas cylinder in air. The gas flow rate was set to 0.7 L/min (to guarantee a suitable linear velocity). Acetaldehyde concentration was monitored online by gas chromatography coupled with a flame ionization detector (GC-FID). Breakthrough curves must allow to understand the interactions between the MOF and the pollutant as well as the impact of the HKUST-1 humidity in the adsorption process. Consequently, different MOF water content conditions were tested, from a dry material with 7 % water content (dark blue color) to water saturated state with approximately 35 % water content (turquoise color). The rough material – without any pretreatment – containing 30 % water serves as a reference. First, conclusions can be drawn from the comparison of the evolution of the ratio of the column outlet concentration (C) on the inlet concentration (Co) as a function of time for different HKUST-1 pretreatments. The shape of the breakthrough curves is significantly different. The saturation of the rough material is slower (20 h to reach saturation) than that of the dried material (2 h). However, the breakthrough time defined for C/Co = 10 % appears earlier in the case of the rough material (0.75 h) compared to the dried HKUST-1 (1.4 h). Another notable difference is the shape of the curve before the breakthrough at 10 %. An abrupt increase of the outlet concentration is observed for the material with the lower humidity in comparison to a smooth increase for the rough material. Thus, the water content plays a significant role on the breakthrough kinetics. This study aims to understand what can explain the shape of the breakthrough curves associated to the pretreatments of HKUST-1 and which mechanisms take place in the adsorption process between the MOF, the pollutant, and the water.

Keywords: acetaldehyde, dynamic adsorption, HKUST-1, pretreatment influence

Procedia PDF Downloads 222
3805 Chaotic Analysis of Acid Rains with Times Series of pH Degree, Nitrate and Sulphate Concentration on Wet Samples

Authors: Aysegul Sener, Gonca Tuncel Memis, Mirac Kamislioglu

Abstract:

Chaos theory is one of the new paradigms of science since the last century. After determining chaos in the weather systems by Edward Lorenz the popularity of the theory was increased. Chaos is observed in many natural systems and studies continue to defect chaos to other natural systems. Acid rain is one of the environmental problems that have negative effects on environment and acid rains values are monitored continuously. In this study, we aim that analyze the chaotic behavior of acid rains in Turkey with the chaotic defecting approaches. The data of pH degree of rain waters, concentration of sulfate and nitrate data of wet rain water samples in the rain collecting stations which are located in different regions of Turkey are provided by Turkish State Meteorology Service. Lyapunov exponents, reconstruction of the phase space, power spectrums are used in this study to determine and predict the chaotic behaviors of acid rains. As a result of the analysis it is found that acid rain time series have positive Lyapunov exponents and wide power spectrums and chaotic behavior is observed in the acid rain time series.

Keywords: acid rains, chaos, chaotic analysis, Lypapunov exponents

Procedia PDF Downloads 131
3804 Potential Cross-Protection Roles of Chitooligosaccharide in Alleviating Cd Toxicity in Edible Rape (Brassica rapa L.)

Authors: Haiying Zong, Yi Yuan, Pengcheng Li

Abstract:

Cadmium (Cd), one of the toxic heavy metals, has high solubility and mobility in agricultural soils and is readily taken up by roots and transported to the vegetative and reproductive organs which can cause deleterious effects on crop yield and quality. Excess Cd in plants can interfere with many metabolic processes, such as photosynthesis, transpiration, respiration or nutrients homeostasis. Generally, the main methods to reduce Cd accumulation in plants are to decrease the concentration of Cd in the soil solution through reduction of Cd influx into the soil system, site selection, and management practices. However, these approaches can be very costly and consume a lot of energy Therefore, it is critical to develop effective approaches to reduce the Cd concentration in plants. It is proved that chitooligosaccharide (COS) can enhance the plant's tolerance to abiotic stress including drought stress, salinity stress, and toxic metal stress. However, so far little information is known about whether foliar application with COS modulates Cd-induced toxicity in plants. The metal detoxification processes of plants treated with COS also remain unclear. In this study, edible rape (Brassica rapa L.), one of the most widely consumed leafy vegetables, was selected as an experimental mode plant. The effect of foliar application with COS on reducing Cd accumulation in edible rape was investigated. Moreover, Cd subcellular distribution pattern in response to Cd stress in the rape plant sprayed with COS was further tested in order to explore the potential detoxification mechanisms in plants. The results demonstrated that spraying COS at different concentrations (25, 50,100 and 200 mg L-1) possess diverse functions including growth-promoting,chlorophyll contents-enhancing, malondialdehyde (MDA) level-decreasing in leaves, Cd2+ concentration-decreasingin shoots and roots of edible rape under Cd stress. In addition, it was found that COS can also dramatically improve superoxide dismutase (SOD) activity, catalase (CAT) activity and peroxidase (POX) activity of edible rape leaves. The relievingeffect of COS was related to theconcentration and COS with 50-100 mg L-1 displayed the best activity. Furtherly, theexperiments results exhibitedthat COS could decrease the proportion of Cd in the organelle fraction of leaves by 40.1% while enhance the proportion of Cd in the soluble fraction by 13.2% at the concentration of 50 mg L-1. The above results showed that COS may have thepotential to improve plant resistance to Cd via promoting antioxidant enzyme activities and altering Cd subcellular distribution. All the results described here open up a new way to study the protection role of COS in alleviating Cd tolerance and lay the foundation for future research about the detoxification mechanism at subcellular level.

Keywords: chitooligosaccharide, cadmium, edible rape (Brassica rapa L.), subcellular distribution

Procedia PDF Downloads 281
3803 PBI Based Composite Membrane for High Temperature Polymer Electrolyte Membrane Fuel Cells

Authors: Kwangwon Seo, Haksoo Han

Abstract:

Al-Si was synthesized and introduced in poly 2,2’-m-(phenylene)-5,5’-bibenzimidazole (PBI). As a result, a series of five Al-Si/PBI composite (ASPBI) membranes (0, 3, 6, 9, and 12 wt.%) were developed and characterized for application in high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). The chemical and morphological structure of ASPBI membranes were analyzed by Fourier transform infrared spectroscopy, X-ray diffractometer and scanning electron microscopy. According to the doping level test and thermogravimetric analysis, as the concentration of Al-Si increased, the doping level increased up to 475%. Moreover, the proton conductivity, current density at 0.6V, and maximum power density of ASPBI membranes increased up to 0.31 Scm-1, 0.320 Acm-2, and 0.370 Wcm-2, respectively, because the increased concentration of Al-Si allows the membranes to hold more PA. Alternatively, as the amount of Al-Si increased, the tensile strength of PA-doped and -undoped membranes decreased. This was resulted by both excess PA and aggregation, which can cause serious degradation of the membrane and induce cracks. Moreover, the PA-doped and -undoped ASPBI12 had the lowest tensile strength. The improved performances of ASPBI membranes imply that ASPBI membranes are possible candidates for HT-PEMFC applications. However, further studies searching to improve the compatibility between PBI matrix and inorganic and optimize the loading of Al-Si should be performed.

Keywords: composite membrane, high temperature polymer electrolyte membrane fuel cell, membrane electrode assembly, polybenzimidazole, polymer electrolyte membrane, proton conductivity

Procedia PDF Downloads 515