Combination Of Response Surface Methodology Research Articles

Optimization of HS-SPME Using Artificial Neural Network and Response Surface Methodology in Combination with Experimental Design for Determination of Volatile Components by Gas Chromatography-Mass Spectrometry in Korla Pear Juice

In this study, the effects of five fibers on volatile compounds of Korla pear (Pyrus bretschneideri rehd) juice were studied. Four main extraction parameters of headspace solid-phase micro-extraction, namely, sample amount, extraction temperature, extraction time, and salt addition, were optimized for the first time using response surface methodology (RSM) and artificial neural network-genetic algorithm (ANN-GA). The prediction and the generalization ability of RSM and ANN models using the same experimental design were compared. The absolute average deviations of the ANN and RSM models were 0.458 and 0.313, and the correlation coefficients were 0.927 and 0.978, respectively. These results indicated that 65-μm PDMS/DVB fiber is the best extraction fiber of SPME for the volatile compounds of Korla pear juice. The ANN model exhibited more accurate prediction and better generalization capabilities than the RSM model, and the optimum conditions obtained by GA were more accurate than those of RSM. The optimum sample amount, extraction temperature, extraction time, and salt addition were 5.33 g, 45 °C, 25 min, and 11.8% of the amount of SPME of the Korla pear juice sample, respectively. Under the optimum conditions, the content of nine volatile compounds, including propanoic acid ethyl ester, 1-hexanal, butanoic acid ethyl ester, 1-hexanol, (E)-2-hexenal, hexanoic acid ethyl ester, 2-hexenal, 1-nonanal, and acetic acid ethyl ester, was 3.37 ± 0.23 μg/g.

Green synthesis of copper nanoparticles by fruit extract of Ziziphus spina-christi (L.) Willd.: Application for adsorption of triphenylmethane dye and antibacterial assay

One of the main subjects in nanoscience is the integration of green chemistry principles to nanotechnology. Recently the ever-increasing need to develop eco-friendly metal nanoparticle synthesis processes is observed. In this research, the ability of the fruit extracts of Ziziphus spina-christi (L.) Willd. was examined as novel reducing agents for the green synthesis of copper nanoparticles (Cu-NPs). Biosynthesized Cu-NPs were characterized by UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). It was found that the as-prepared Cu-NPs can be used as an efficient adsorptive nanomaterial to remove crystal violet (CV), from aqueous solution. The effects of independent variables such as pH, initial dye concentration, adsorbent dosage and stirring time on CV removal were studied using central composite design (CCD). Optimization of the variables for maximum adsorption of target dye was performed using desirability function (DF) combined response surface methodology (RSM). The results showed that 95% of CV with a high adsorption capacity (37.5mgg−1) was removed with a little amount of adsorbent (80mg) in a short time (7.5min). In addition, antibacterial activity of the Cu-NPs was studied on two different (g− and g+) bacteria; Escherichia coli and Staphylococcus aureus.

Non-destructive evaluation of nano silica-modified roller-compacted rubbercrete using combined SonReb and response surface methodology

Roller-compacted concrete (RCC) is being widely used in highway construction industry (for pavement applications) due to its enormous advantages over conventional concrete rigid pavement. However, the major problems related to RCC pavement are the rigidity and relative tendency to crack due to low tensile strength. To address this problem, crumb rubber (CR) can be added as partial replacement of fine aggregate. High elastic and deformation properties of CR will increase the ductility of RCC pavement to absorb the deformation and strain energy caused by traffic loads. However, incorporating CR to RCC pavement leads to a reduction in mechanical properties which needs to be addressed for proper utilisation. Therefore, in this study, roller-compacted rubbercrete (RCR) was produced by partially replacing fine aggregate with CR. Nano silica was used as an additive to cement to mitigate the loss of mechanical properties in RCR caused by incorporation of CR. The non-destructive tests, that is, rebound hammer test and ultrasonic pulse velocity (UPV) were used to evaluate the performance of RCR. Response surface methodology was then used to develop models for predicting the 28 days UPV and rebound number (RN) of RCR. Combined UPV–RN (SonReb) models for predicting the 28 days strength of RCR based on combining UPV and RN were developed using multivariable regression (double power, bilinear, and double exponential models). From the combined SonReb models formulated, it is concluded that the double exponential model has better accuracy for predicting the 28 days compressive strength of RCR compared to the double power models recommended by RILEM 43-CND for conventional concrete.

Optimization of culture media for extracellular expression of streptokinase in Escherichia coli using response surface methodology in combination with Plackett-Burman Design

Purpose: To investigate the enhancement of streptokinase extracellular expression in Escherichia coli by adjusting culture media.Methods: Screening of 10 chemical factors (EDTA, peptone, glycine, triton X-100, glycerol, K2HPO4, KH2PO4, Ca2+ (calcium chloride), yeast and NaCl) in order to increase the secretion of extracellular protein was carried out by response surface methodology (RSM). The method was also employed to optimize the concentrations of critical factors that had been determined in the screening step.Results: The results indicate that glycine, triton X-100 and Ca2+ were the most effective chemical factors in terms of increase in extracellular expression of streptokinase with optimum levels of 0.878, 0.479 and 0.222 %, respectively. Expression of streptokinase under optimum concentrations of critical permeabilizing factors led to a 7-fold increase in the quantity of secreted recombinant protein (5824 U/mL) compared to the initial level (802 U/mL).Conclusion: The results show that medium optimization using RSM is effective in improving extracellular streptokinase expression. The optimization medium is considered fundamental and useful for efficient production of streptokinase on a large scale.Keywords: Streptokinase, Response surface methodology, Membrane permeabilization, Extracellular secretion

Green Synthesized Silver Nanoparticles and Their Impact on the Antioxidant Response and Histology of Indian Major Carp Labeo rohita, with Combined Response Surface Methodology Analysis

Biosynthesis of silver nanoparticles has received considerable attention due to their cost-effective, eco-friendly and medicinal values. In this study, silver nanoparticles (Ag NPs) were synthesised using the aqueous leaf extracts of Piper nigrum. TEM images revealed that the particle is spherical with 20–50 nm in size. Furthermore, to evaluate the toxicity of synthesized Ag NPs, fish Labeo rohita were exposed to two different concentrations (2.5 µg/L as the treatment I and 5 µg/L as treatment II) for 35 days, and antioxidant parameters and histology of gill, liver and kidney were examined. A biphasic response in the activity of glutathione S-transferases (GST) was observed in gill and liver of fish. GST activity in the kidney of fish was significantly increased when compared to control group. Glutathione reductase (GR) activity in organs/tissue of fish were found to be increased while peroxidase (POD) activity was significantly decreased. Histopathological changes such as hyperplasia, proliferation of epithelial cells and fusion of lamellae were observed in both the concentrations. In liver, necrosis, nuclear degeneration and dilation of sinusoids were observed. Subsequently, the representative effects of POD activity were assessed based on the Box–Behnken Equation, 3-D contour plot and ANOVA analysis through response surface methodology analysis.

Efficient preparation of narcissin from Opuntia ficus-indica fruits by combination of response surface methodology and high-speed countercurrent chromatography

Background: Narcissin is well known for their various biological activities. Objective: To recover narcissin from the Opuntia ficus-indica fruits (OFIF), an efficient method was developed by a combination of response surface methodology (RSM) and high-speed countercurrent chromatography (HSCCC). Materials and Methods: Optimization of extraction conditions of narcissin from OFIF was determined using RSM with three-level-three-factor Box-Behnken design (BBD). Then, a rapid and efficient method for the isolation of narcissin from the rich narcissin extracts was developed using HSCCC. Results: Regression analysis showed a good fit of the experimental data and the optimal condition was obtained as extraction time (X1), 6.02 h; solvent to material ratio (X2), 8.16 mL/g; and ethanol concentration (X3), 93.48%. Then, the rich narcissin extracts were separated by HSCCC with a two-phase solvent system composed of n-hexane: ethyl acetate: methanol: water (1.5:5:5:1.5, v/v/v/v) in one step within 60 min. As a result, 12 mg of narcissin was isolated from 100 mg of crude extract with purities of 98.5%, as determined by high-performance liquid chromatography (HPLC). Conclusion: This study can be useful to the development of industrial extraction processes, including further studies concerning the optimal number of sequential steps to enhance the efficacy of a large-scale extraction system. Abbreviations used: BBD: Box-Behnken design; HPLC: High-performance liquid chromatography; HSCCC: High-speed countercurrent chromatography; OFIF: Opuntia ficus-indica fruits; RSM: Response surface methodology

Modeling and Optimum Extraction of Multiple Bioactive Exopolysaccharide from an Endophytic Fungus of Crocus sativus L.

Background:Crocus sativus L. (saffron) is a scarce plant that has been used as food flavoring agent, coloring agent, and traditional herbal medicine.Methods:The bioactivity of exopolysaccharide (EPS) extracted from an endophytic fungus of C. sativus was examined for the first time by antioxidative, antitumor, and antibacterial assays. The extraction conditions for EPS were optimized by combining the response surface methodology with Box-Behnken design.Results:EPS exhibited excellent scavenging activities against 1,1-diphenyl-2-picrylhydrazyl, hydroxyl and superoxide anion radicals, and moderate cytotoxicities against K562, A549, HL-60, and HeLa cells. The optimum extraction conditions for EPS were as follows: precipitation time of 16 h, precipitation temperature of 3.7°C, pH 7.2, and ratio of ethanol to fermented broth of 5:1 (L/L). Under the optimized conditions, the yield of EPS reached 162 ± 6 μg/L which was close to the predicted one (165 μg/L). Moreover, high-performance liquid chromatography of monosaccharide composition showed that EPS comprised mannose, glucose, galactose xylose, and arabinose in a molar ratio of 25.6:16.5:1.0:3.8:5.4.Conclusion:EPS may be an eligible substitute for C. sativus and a potential bioactive source applicable to pharmaceutical and food industries.SUMMARY Exopolysaccharide (EPS) from endophytic fungus of Crocus sativus was studied for the first timeEPS extraction was optimized by combining response surface methodology with Box-Behnken designMonosaccharide composition and EPS structure were identified by high-performance liquid chromatography and Fourier-transform infrared spectroscopy. Abbreviations used: EPS: Exopolysaccharide, RSM: Response surface methodology, BBD: Box-Behnken design, DPPH: 1,1-diphenyl-2-picrylhydrazyl, VC: Ascorbic acid, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, LB: Luria Bertani, DMSO: dimethyl sulfoxide, PMP: 1-phenyl-3-methyl-5-pyrazolone, FT-IR: Fourier transform-infrared, HPLC: High-performance liquid chromatography, 3D: Three-dimensional, 2D: Two-Dimensional.

Optimisation of EDM process for MRR, TWR and radial overcut of D2 steel: a hybrid RSM-GRA and entropy weight-based TOPSIS approach

In this research, a distinct combination of response surface methodology (RSM), gray relational analysis (GRA) with Shannon's entropy measurement-based technique for order preference by similarity to ideal solution (TOPSIS) method has been suggested to assess, improve and estimate the influence of the process parameters on responses characteristics. The electrical discharge machining (EDM), parameters pulse current (Ip), pulse duration (Ton), duty cycle (Tau) and discharge voltage (V) were input, and, material removal rate (MRR), tool wear rate (TWR) and radial overcut or gap (G) were considered as output parameters. The R2 value for the relative closeness was found to be 96.83%. The ANOVA reveals that Ip is the most influencing parameter with 46.49% contribution followed by Ton, Tau and V with 13.92%, 7.35% and 2.8%, respectively. The interaction of parameters contributes 15.26%. This study can be used as a scientific source for parameter optimisation in concerned manufacturing processes.

Optimisation of EDM process for MRR, TWR and radial overcut of D2 steel: a hybrid RSM-GRA and entropy weight-based TOPSIS approach

In this research, a distinct combination of response surface methodology (RSM), gray relational analysis (GRA) with Shannon's entropy measurement-based technique for order preference by similarity to ideal solution (TOPSIS) method has been suggested to assess, improve and estimate the influence of the process parameters on responses characteristics. The electrical discharge machining (EDM), parameters pulse current (Ip), pulse duration (Ton), duty cycle (Tau) and discharge voltage (V) were input, and, material removal rate (MRR), tool wear rate (TWR) and radial overcut or gap (G) were considered as output parameters. The R2 value for the relative closeness was found to be 96.83%. The ANOVA reveals that Ip is the most influencing parameter with 46.49% contribution followed by Ton, Tau and V with 13.92%, 7.35% and 2.8%, respectively. The interaction of parameters contributes 15.26%. This study can be used as a scientific source for parameter optimisation in concerned manufacturing processes.

Optimization the machining parameters by using VIKOR Method during EDM process of Titanium alloy

The objective of this work is to estimate the optimised Electrical discharge machining (EDM) parameters for maximum productivity and minimum surface integrity using combined RSM (Response Surface Methodology) and VIKOR method. The effect of four process parameters; namely Pulse on time (Ton), Peak current (Ip) Duty Cycle (Tau), and Supply Voltage (V) on the responses such as Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) have been considered. Thirty experiments were conducted on Ti-6Al-4V (Titanium alloy) work piece with copper tool using Central Composite Design (CCD).The optimal Condition of experiment were determine using the Pi value obtained from VIKOR method, a multi criteria decision making method which determines the raking list based on the particular measure of closeness to ideal solution. From the analysis it is found that the Ip = 12A, Ton=100μsec, Tau=18%, V=30V provides highest Pi values.so found to better best equilibrium. As per the Computed means of VIKOR index Ip is the most vital parameter followed by Tau, Ton, and V respectively. The result is confirmed by conducting conformation test and found to be comparable with the result. The findings of the study provides the valuable information regarding the regulate the machining parameters, the responses and confirm higher MRR and accuracy of the EDMed products.

Optimization of rhamnolipid biosurfactant production from Serratia rubidaea SNAU02 under solid-state fermentation and its biocontrol efficacy against Fusarium wilt of eggplant

Abstract This work was aimed to explore rhamnolipid production under solid state fermentation using a potential substrate mahua oil cake and to evaluate the biocontrol efficacy of rhamnolipid against Fusarium wilt of eggplant. The combination of Response Surface Methodology and Central Composite Design was employed to optimize higher biosurfactant production. Therefore, four factors viz., substrate concentration, inoculum size, pH and temperature were selected for optimization of rhamnolipid production. The results revealed that the optimum conditions for reduction of surface tension were mahua oil cake 7.78 g, 2.4 ml inoculum size (1 × 108 cells/ml), pH 7 and 30° C temperature. To evaluate the biocontrol efficacy the application of rhamnolipid at various concentrations (0, 100, 250 and 500 μg/ml) by soil and foliar application were employed in the pot culture assay. In vitro study indicated that rhamnolipid producing strain SNAU02 was the most effective antagonist against Fusarium oxysporum f. sp. melongenae and used for pot culture study. On the basis of economic analysis, treatment T9 (Fusarium oxysporum f. sp. Melongenae ( × 106 spores/ml) + 50 ml of 250 μg biosurfactant/ml to soil + foliar spraying of biosurfactant (250 μg/ml) ranked among the efficacious treatments and was just as effective as a synthetic fungicide. In control treatment, occurrence of disease severity and disease incidence was observed from early stage of crop growth until harvest stage. The pot experiment results indicated that SNAU02 rhamnolipid could be a promising agent in the biocontrol of Fusarium wilt of eggplant, which might help to minimize the yield loss of eggplant.

Modelling hydrolysis of leaf litter by digestive enzymes of the snail Melanopsis praemorsa: combination of response surface methodology and in vitro assays

The objective of the present study was to test the application of an in vitro assay simulating the digestive hydrolysis of leaf litter by the freshwater snail M. praemorsa, as well as to determine the possible influence of different factors in the efficiency of such process to release biologically available C and N under the forms of reducing sugars and amino acids from two different substrates. A novel approach to construct a model explaining the effect of three main factors (temperature, total reaction time and enzyme:substrate ratio) in the digestive hydrolysis of cellulose and protein present in leaf litter of different nutritive value is used. The methodology combines a factorial design based in the response surface methodology (RSM) and in vitro digestibility assays adapted to the physiology of both plant substrates used (alder and poplar leaves). The model revealed a different influence of the factors in the hydrolysis of two plant substrates, poplar and alder leaves and the main effect was produced by the time available for hydrolysis. A compensation response based in a longer gut retention time for the lower quality substrate was observed in the feeding assays. The use of in vitro assays and RSM provides a useful insight on the effect of factors and mechanisms underlying the observed differences in nutritional value of leaf litter for an aquatic invertebrate, being such differences linked to the whole bioavailability of carbon and nitrogen in headwater streams.

Optimization and kinetic study of CaO nano-particles catalyzed biodiesel production from Bombax ceiba oil

An attempt has been made to optimize biodiesel production from Bombax ceiba oil (BCO) through calcium oxide nanoparticles (CaO-NPs) catalyzed transesterification. Characterization of CaO-NPs synthesised by solution combustion method was carried out using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Brunauer-Emmett Teller (BET) and Thermogravimetric analysis (TGA). The influence of reaction parameters was studied and optimized by using Response Surface Methodology (RSM) in combination with central composite design (CCD). Two-stage transesterification technique was employed for biodiesel production and 96.2% yield of Bombax ceiba methyl ester (BCME) was achieved under optimum conditions. The CaO-NPs were reused up to 5 cycles with appreciable loss of yield. From the kinetic study performed at different reaction temperatures (55 °C, 60 °C and 65 °C) Ea = 35.99 kJ/mol was obtained. Fuel properties of produced methyl ester were also determined and compared with ASTM standards for biodiesel.

Green synthesized iron nanoparticles supported on pH responsive polymeric membrane for nitrobenzene reduction and fluoride rejection study: Optimization approach

Iron nanoparticles (NPs) were prepared via Clove extract mediated green synthesis. Iron NPs were immobilized in flat asymmetric polymeric pH responsive PVDF-co-HFP membranes prepared by blending of Polyethylene glycol methyl ether (PEGME)(Mw = 5000 g/mol) and Humic acid (HA). Iron NPs dispersed in pH responsive polymeric membrane in different weight percentage (0.01, 0.1 and 1) imparted catalytic effect in reducing nitrobenzene to aniline as well as enhanced fluoride rejection by dead end filtration experiment. Both the process of NB reduction and fluoride rejection was dependent on pH responsiveness of the membrane. High performance liquid chromatography (HPLC) analysed formation of aniline and nitrobenzene at different ultra-filtration time. Aniline formation of 15 ppm was found to be highest at pH3 and lowest of 12.8 ppm at pH7 for 0.01 wt% iron NPs impregnated membrane at end of 50 min. Aniline formation increased for pH12 than pH7 due to pH responsiveness. Fluoride rejection was studied on optimized wt% of iron NPs from NB reduction experiments with different pH of fluoride solutions. In order to maximize the Aniline formation and Nitrobenzene reduction, the variables (time, pH and wt% of NPs) was optimized using Design expert software 9.0 TRIAL through ANOVA (analysis of variance) using the combination of response surface methodology (RSM) and central composite design (CCD). The optimization study showed negligible error with experimentally obtained values at optimized conditions for maximizing NB reduction (error 3.37%) and aniline formation (error 3.93%).

Multi-Objective Parameter Optimization for Cross-Sectional Deformation of Double-Ridged Rectangular Tube in Rotary Draw Bending by Using Response Surface Methodology and NSGA-II

Cross-sectional deformation of double-ridged rectangular tube (DRRT) inevitably occurs due to the inhomogeneous deformation induced by external boundary conditions in rotary draw bending (RDB). Unreasonable factor combination would aggravate the cross-sectional deformation of DRRT. So, a powerful and efficient method combining Response Surface Methodology (RSM) and Non-Sorted Genetic Algorithm II (NSGA-II) was proposed to optimize the factors to control the cross-sectional deformation of DRRT in RDB. Firstly, an orthogonal experiment was used to screen out the important factors. It was obtained that three factors—clearance between DRRT and mandrel, clearance between DRRT and bending die, and boosting of pressure die—have an important influence on the cross-sectional deformation of DRRT. It can also be observed that the variation trend of flange sagging (FS) is always consistent with that of space deformation between ridges (SDR) with the changing of factors. RSM based on a Box-Behnken design was then used to establish response surface models. The proposed response surface models were used to analyze the relationship of the important parameters to the responses, such as space deformation between ridges, and width deformation of outer and inner ridge grooves (WDO and WDI). Finally, multi-objective parameter optimization for the cross-sectional deformation of DRRT in RDB was performed by using the established model and NSGA-II algorithm. The interaction of responses was revealed and the value range of each response in the space of Pareto optimal solutions was determined. It can be observed that there is always an evident conflict between SDR and WDO in the space of Pareto optimal solutions. By using this optimization method, the absolute values of SDR and WDI were significantly reduced—by 13.17% and 17.97%, respectively—compared with those before optimization, while WDO just increase only a little.

Investigation of anti-corrosion ability of nano mixed metal oxide pigment dispersed alkyd coating and its optimization for A36 steel

This paper describes the mechanism behind the anti-corrosion behavior of mixed metal oxide (MMO) dispersed alkyd resin coating obtained via high energy ball milling. MMOs such as TiO2·Fe2O3 TiO2·ZnO and TiO2·NiO are prepared by adopting sol-gel and gel combustion techniques. The crystallite size and the morphology of the MMO pigments are analyzed using XRD and FESEM respectively. The XRD pattern reveals that the synthesized pigments are highly crystalline in nature. The composition and purity of the pigments are analyzed by EDX analysis. 20 wt. % of prepared MMO is dispersed in alkyd resin along with suitable non-toxic additives to prepare alkyd coating. The obtained suspension is coated and dried over A36 structural steel by brushing method. The corrosion inhibition properties of the coating are studied by potentiodynamic polarization measurements and wet corrosion techniques. The specimens coated with alkyd resin containing MMO pigments exhibit higher corrosion protection efficiencies of 98.18% (TiO2·Fe2O3), 99.19% (TiO2·ZnO) and 86.15% (TiO2·NiO) respectively in different acid media. Response surface methodology in combination with the Box-Behnken design is used to optimize the best corrosion inhibitive pigment in the coating in different kinds of acid. ANOVA indicates the influencing factor with a confidence level of 0.991 by comparing the F-value obtained with F-test value. The optimized results show that the coating consisting of TiO2·ZnO displays minimum weight loss (2.4 mg in 0.1 N HNO3), with high inhibition efficiency (99.48%) and lower corrosion rate (2.34 mpy).

Effect of Polyethylene glycol methyl ether blend Humic acid on poly (vinylidene fluoride-co-hexafluropropylene) PVDF-HFP membranes: pH responsiveness and antifouling behavior with optimization approach

Flat sheet asymmetric membranes were fabricated with homogeneous solution of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) using N-methyl-2-pyrrolidone (NMP) as solvent via phase inversion method. PEGME (Poly ethylene glycol methyl ether) (Mn 5000) blend Humic Acid (HA), of different mole ratio was used as additive. Characterization of the membranes was done by Field emission scanning electron microscope (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, Atomic force microscopy (AFM) and Differential scanning calorimetry (DSC) studies. Liquid-liquid displacement porosimetry (LLDP) study evaluated the morphological parameters, average pore size and pore size distribution. Bovine serum albumin (BSA) (MW - 68,000 Da) was used to study the antifouling effect and pore blocking mechanism of the membranes. The pure water flux (PWF), solute rejection and flux recovery ratio drastically increases for the PEGME blended HA membranes whereas the water contact angle decreases significantly. The pH responsiveness character of the prepared membranes altered the hydraulic permeability and rejection % at different pH. Finally, optimization of the variables contributing towards the PWF and BSA rejection of the desired membrane was performed using Design expert software 9.0 TRIAL through ANOVA (analysis of variance) using the combination of response surface methodology (RSM) and central composite design (CCD).

Estimating the effect of different factors on the digestive bioaccessibility of protein by the Senegalese sole (Solea senegalensis); combination of response surface methodology and in vitro assays

The present work uses a novel approach to develop a mathematical model explaining the effect of three main factors - temperature, total reaction time and enzyme:substrate ratio - in the hydrolysis of protein by the intestinal enzymes of the Senegalese sole. The methodology combines a factorial design based in the Response Surface Methodology and in vitro digestibility assays adapted to the physiology and culture conditions of the species. The model revealed that, within the physiological ranges considered in the study, the efficiency of protein hydrolysis by the intestinal enzymes of the sole was linearly correlated to two of the selected factors; directly to incubation time and inversely to the amount of substrate. The effect of temperature was not linear but quadratic, hence showing a maximum at 23°C. The information obtained can be used as a tool to maximize the biological response under variable conditions and may orientate some on-farm feeding practices.

Development of aminated poly(glycidyl methacrylate) nanosorbent by green gamma radiation for phenol and malathion contaminated wastewater treatment

Green gamma (γ) radiation technology is used for the synthesis of quaternary amine-functionalized polymeric (NPGMA) nanosorbent resin from the reaction of glycidyl methacrylate (GMA) monomer and triethylamine precursors. Response surface methodology (RSM) in combination with regression modeling and ANOVA statistics were used to evaluate and optimize the NPGMA adsorption conditions for phenol and malathion pollutants from artificial wastewater containing inorganic constituents of an actual water system. The pseudo-second-rate equation assisted by surface diffusion with a monolayer and endothermic processes described the mechanism of phenol and malathion adsorption by NPGMA nanosorbent well. The selectivity coefficient of NPGMA towards malathion is found to be higher than phenol by 34–46 times with optimum capacities of 47.26mg/g and 66.83mg/g for phenol and malathion and good reusability. An increasing of divalent inorganic moieties including SO42− group is found to have a low antagonistic effect on the adsorption capacity by NPGMA. Further, the total treatment cost can be estimated to be 2.91–3.19$/cubic meter of wastewater containing concentrated 100mg/L of phenol and malathion contaminants, assuming that the NPGMA sorbent is reused three times successively. Overall, it can be inferred that the prepared NPGMA nanosorbent by gamma radiation can efficiently treat both industrial and agricultural wastewaters for better control of water pollutions.

Application of central composite design for methyl red dispersive solid phase extraction based on silver nanocomposite hydrogel: Microwave assisted synthesis

In this study microwave irradiation was used to synthesis the silver nanocomposite hydrogel and the usefulness as an adsorbent for the preconcentration, extraction and determination of methyl red (MR) from water by dispersive solid phase extraction method was evaluated. For this purpose, silver nanocomposite hydrogel (SNH) was synthesized and characterized by thermo-gravimetric (TG) analysis, FT-IR, TEM and SEM images. The effects of some important variables such as centrifuge time (min), the pH of the methyl red solution, amount of adsorbent (g), acetone volume (mL) and chloroform volume (mL) on methyl red removal were studied using central composite design (CCD) and the optimum experimental conditions were evaluated by the desirability function (DF) combined response surface methodology (RSM). Under the optimal experimental conditions, the detection limit was found to be 1.4μgmL−1 for MR adsorption. The limit of quantification and the linear range of calibration curve were 4.6μgmL−1 and 0.1–25μgmL−1, respectively.