Optimization of Extraction Process of Clerodendrum philippinum Schauer var. simplex Mlodenke Total Flavonoids(CPTF) by Central Composite Design-Response Surface Methodology

[Objectives] The research aimed to optimize extraction process of Clerodendrum philippinum Schauer var. simplex Mlodenke total flavonoids( CPTF),and provide reference for its development and utilization. [Methods] Based on single-factor test,ethanol concentration,extraction temperature and extraction time were taken as independent variables,and total flavonoids yield was taken as dependent variable. The test was conducted according to central composite design principle. Multivariate linear regression and binomial equation fitting of the result were conducted,and extraction process of CPTF was optimized by using response surface methodology. [Results]The optimal extraction process of CPTF was as below: ethanol concentration 54. 76%,extraction temperature 83. 92℃,extraction time 102. 64 min,solid-liquid ratio 1:20,extraction for twice. [Conclusions] The extraction process of CPTF by central composite design-response surface methodology was simple and feasible,with reliable prediction result,which was suitable for industrial production.

Optimization of Extraction Process of Total Flavonoids from Akebia trifoliata (Thunb.) Koidz. by Central Composite Design-Response Surface Methodology

[Objectives]To optimize extraction process of total flavonoids from Akebia trifoliata( Thunb.) Koidz.,so as to provide references for development and use of Akebia trifoliata( Thunb.) Koidz. [Methods]The extraction rate of total flavonoids of Akebia trifoliata( Thunb.)Koidz. was taken as observation indicator. On the basis of single factor experiment,central composite design( CCD) was used to evaluate the effects of the extraction temperature,extraction time,and ethanol concentration on the extraction process. Multiple linear regression and binomial fitting were used,and response surface methodology( RSM) was used to select the optimum extraction process. [Results] The optimum extraction process conditions for total flavonoids of Akebia trifoliata( Thunb.) Koidz. was extraction temperature: 83. 92 ℃; extraction time:96. 47 min; ethanol concentration: 63. 92%; extraction times: two times; solid to liquid ratio: 1 ∶ 20; extraction rate of total flavonoids:4. 55%. [Conclusions] The central composite design-response surface methodology( CCD-RSM) is simple,convenient,and feasible for extraction of total flavonoids from Akebia trifoliata( Thunb.) Koidz.,and the prediction results are reliable.

Response Surface Methodology-Based SERS for Determination of Gymnodimine

Gymnodimine (GYM), a fast-acting marine toxin, is destructive to aquaculture and human health through contaminated shellfish. The current detection methods in GYM have definite drawbacks in operation, such as the demand for delicate instruments and the consumption of time. Therefore, silver colloid was utilized as a surface-enhanced Raman scattering (SERS) desirable substrate for sensitive and rapid detection of GYM in lake and shellfish samples. The theoretical spectrum of GYM is calculated by density functional theory (DFT), and the substrate performance is evaluated by a rhodamine 6 G probe. Under the optimal SERS experimental condition calculated by the response surface methodology, the low limit of detection of 0.105 μM with R2 of 0.9873 and a broad linearity range of 0.1 - 10 μM was achieved for GYM detection. In addition, the substrate was satisfyingly applied to detect gymnodimine in the lake and shellfish matrix samples with LOD as low as 0.148 μM and 0.170 μM, respectively. These results demonstrated a promising SERS platform for detecting marine toxins in seafood for food safety and pharmaceutical research.

Optimizing electrocoagulation process for the treatment of biodiesel wastewater using response surface methodology

The production of biodiesel through a transesterification method produces a large amount of wastewater that contains high levels of chemical oxygen demand （COD） and oil and grease （O＆G）. Currently, flotation is the conventional primary treatment for O＆G removal prior to biological treatments. In this study, electrocoagulation （EC） was adopted to treat the biodiesel wastewater. The effects of initial pH, applied voltage, and reaction time on the EC process for the removal of COD, O＆G, and suspended solids （SS） were investigated using one factor at a time experiment. Furthermore, the Box-Behnken design, an experimental design for response surface methodology （RSM）, was used to create a set of 15 experimental runs needed for optimizing of the operating conditions. Quadratic regression models with estimated coefficients were developed to describe the pollutant removals. The experimental results show that EC could effectively reduce COD, O＆G, and SS by 55.43%, 98.42%, and 96.59%, respectively, at the optimum conditions of pH 6.06, applied voltage 18.2 V, and reaction time 23.5 min. The experimental observations were in reasonable agreement with the modeled values.

Deformation prediction and analysis of underground mining during stacking of dry gangue in open-pit based on response surface methodology

Deformation prediction and the analysis of underground goaf are important to the safe and efficient recovery of residual ore when shifting from open-pit mining to underground mining.To address the comprehensive problem of stability in the double mined-out area of the Tong-Lv-Shan(TLS)mine,which employed the dry stacked gangue technology,this paper applies the function fitting theory and a regression analysis method to screen the sensitive interval of four influencing factors based on single-factor experiments and the numerical simulation software FLAC3D.The influencing factors of the TLS mine consist of the column thickness(d),gob area span(D),boundary pillar thickness(h)and height of tailing gangue(H).The fitting degree between the four factors and the displacement of the gob roof(W)is reasonable because the correlation coefficient(R2)is greater than0.9701.After establishing29groups that satisfy the principles of Box-Behnken design(BBD),the dry gangue tailings process was re-simulated for the selected sensitive interval.Using a combination of an analysis of variance(ANOVA),regression equations and a significance analysis,the prediction results of the response surface methodology(RSM)show that the significant degree for the stability of the mined-out area for the factors satisfies the relationship of h>D>d>H.The importance of the four factors cannot be disregarded in a comparison of the prediction results of the engineering test stope in the TLS mine.By comparing the data of monitoring points and function prediction,the proposed method has shown promising results,and the prediction accuracy of RSM model is acceptable.The relative errors of the two test stopes are1.67%and3.85%,respectively,which yield satisfactory reliability and reference values for the mines.

Optimization of a fermented pumpkin-based beverage to improve Lactobacillus mali survival and-glucosidase inhibitory activity:A response surface methodology approach

The aim of this research was to develop an optimum fermentation and composition model for a new fermented pumpkin-based beverage with high probiotic survival and-glucosidase inhibitory activity.Relationship between fermentation temperature,inoculum and ingredient concentration with response variables(fermentation time at the fermentation endpoint pH 4.5,survival rate of Lactobacillus mali K8 in pumpkin-based beverage treated with simulated gastrointestinal tract enzyme fluids,-glucosidase inhibitory activity and sensory overall acceptability after 4 weeks of refrigerated storage)was investigated using response surface methodology.Optimal formulation was obtained at an approximation of 40%pumpkin puree concentration,8 Log CFU/mL inoculum and at 35℃.The product derived from this optimum formula reached the fermentation endpoint after 28.34±0.10 h and the quality change during 4 weeks storage was studied.The product achieved 88.56±0.67%of L.mali survival after treatment with simulated gastric and intestinal juices;demonstrated 95.89±0.30% α-glucosidase inhibitory activity,as well as scored 6.99±0.40 on sensory overall acceptability after 4 weeks of storage.These findings illustrated that the model is effective in improving probiotic survival and α-glucosidase inhibitory activity with excellent sensory acceptability,thus may offer a dietary means for the management of hyperglycaemia.

Comparison of Response Surface Methodology and Artificial Neural Network in Predicting the Microwave-Assisted Extraction Procedure to Determine Zinc in Fish Muscles

In this paper, the estimation capacities of the response surface methodology (RSM) and artificial neural network (ANN), in a microwave-assisted extraction method to determine the amount of zinc in fish samples were investigated. The experiments were carried out based on a 3-level, 4-variable Box–Behnken design. The amount of zinc was considered as a function of four independent variables, namely irradiation power, irradiation time, nitric acid concentration, and temperature. The RSM results showed the quadratic polynomial model can be used to describe the relationship between the various factors and the response. Using the ANN analysis, the optimal configuration of the ANN model was found to be 4-10-1. After predicting the model using RSM and ANN, two methodologies were then compared for their predictive capabilities. The results showed that the ANN model is much more accurate in prediction as compared to the RSM.

Multiple-response optimization for melting process of aluminum melting furnace based on response surface methodology with desirability function

To reduce the fuel consumption and emissions and also enhance the molten aluminum quality, a mathematical model with user-developed melting model and burning capacity model, were established according to the features of melting process of regenerative aluminum melting furnaces. Based on validating results by heat balance test for an aluminum melting furnace, CFD （computational fluid dynamics） technique, in association with statistical experimental design were used to optimize the melting process of the aluminum melting furnace. Four important factors influencing the melting time, such as horizontal angle between burners, height-to-radius ratio, natural gas mass flow and air preheated temperature, were identified by PLACKETT-BURMAN design. A steepest descent method was undertaken to determine the optimal regions of these factors. Response surface methodology with BOX-BEHNKEN design was adopted to further investigate the mutual interactions between these variables on RSD （relative standard deviation） of aluminum temperature, RSD of furnace temperature and melting time. Multiple-response optimization by desirability function approach was used to determine the optimum melting process parameters. The results indicate that the interaction between the height-to-radius ratio and horizontal angle between burners affects the response variables significantly. The predicted results show that the minimum RSD of aluminum temperature （12.13%）, RSD of furnace temperature （18.50%） and melting time （3.9 h） could be obtained under the optimum conditions of horizontal angle between burners as 64°, height-to-radius ratio as 0.3, natural gas mass flow as 599 m3/h, and air preheated temperature as 639 ℃. These predicted values were further verified by validation experiments. The excellent correlation between the predicted and experimental values confirms the validity and practicability of this statistical optimum strategy.

Optimization of High-Gravity Chelated Iron Process for Removing H_2S Based on Response Surface Methodology

By using a mixture of N2 and H2S as the simulated APG(associated petroleum gas), the desulfurization experiment was performed in a cross-flow rotating packed bed(RPB) based on the chelated iron oxidation-reduction method. In order to determine the operating conditions of the system, the effects of the concentration of Fe3+ ions(ranging from 0.1 to 0.2 mol/L), the liquid-gas volume ratio(ranging from 15 to 25 L/m3) and the high gravity factor(ranging from 36 to 126) on the removal of H2 S were studied by means of the Box-Behnken design(BBD) under response surface methodology(RSM). The overall results have demonstrated that the BBD with an experimental design can be used effectively in the optimization of the desulfurization process. The optimal conditions based on both individualized and combined responses(at a Fe3+ ion concentration of 0.16 mol/L, a liquid-gas volume ratio of 20.67 L/m3 and a high gravity factor of 87) were found. Under this optimum condition, the desulfurization efficiency could reach 98.81% when the H2 S concentration was 7 g/m3 in APG. In this work, the sulfur product was analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM) and the energy dispersive X-ray spectrometer(EDX). The results of analysis show that the sulfur is made of the high-purity orthorhombic crystals, which are advantageous to environmental conservation.

Optimization of Extraction Process and Determination of Total Triterpenoids from Semen Trichosanthis by Response Surface Methodology

[Objectives] To optimize the extraction process and determine the total triterpenoids from Semen Trichosanthis.[Methods]The Box-behnken response surface methodology was applied to optimize the extraction conditions of total triterpenoids in Semen Trichosanthis.And the spectrophotometry was used to determine the content of total triterpenoids in Semen Trichosanthis.[Results] The optimal extraction conditions were solid to liquid ratio of 40∶ 1,ultrasonic time of 20 min,and ultrasonic power of 100 W.Under these conditions,the content of total triterpenoids in Semen Trichosanthis was significantly different among the 10 production areas,among which the No.9 production area(Anhui 1) had the highest total triterpenoids content of 45.71 mg/g,while No.7 production area(Shandong) had the lowest total triterpenoids content of 15.22 mg/g.[Conclusions]The Box-behnken response surface methodology is reliable for the extraction of total triterpenoids in Semen Trichosanthis,and the spectrophotometry is proper for determining the content of total triterpenoids in Semen Trichosanthis.There are large differences in the content of total triterpenoids in Semen Trichosanthis produced in different areas.

Removal of Mercury(Hg(Ⅱ)) from Seaweed Extracts by Electrodialysis and Process Optimization Using Response Surface Methodology

In this work,response surface methodology(RSM)was employed to model and optimize electrodialysis process for mercury(Hg(II))removal from seaweed extracts.Box-Behnken design(BBD)was utilized to evaluate the effects and the interaction of influential variables such as operating voltage,influent flow rate,initial concentration of Hg(II)on the removal rate of Hg(II).The developed regression model for removal rate response was validated by analysis of variance,and presented a good agreement of the experimental data with the quadratic equation with high value coefficient of determination value(R2=0.9913,RAdj 2=0.9678).The optimum operating parameters were determined as 7.17V operating voltage,72.54L h−1 influent flow rate and 5.04mgL−1 initial concentration of mercury.Hg(II)removal rate of 76.45%was acquired under the optimum conditions,which showed good agreement with model-predicted(75.81%)result.The results revealed that electrodialysis can be considered as a promising strategy for removal of Hg(II)from seaweed extracts.

Optimization of Rhododendri Daurici oil liposome by Box-Behnken design and response surface method

Objective:To prepare the liposomes of mangrove oil,Optimization of the formulation of mangrove oil liposomes by Box Behnken response surface methodology.Methods:Preparation of Rhododendron oil liposomes by ethanol injection probe ultrasound,Determination of gemacrone by HPLC.The ratio of lecithin to cholesterol(X1),drug lipid ratio(X2)and phospholipid concentration(X3)were used as independent variables,and encapsulation efficiency(Y)was used as dependent variable,the formulation was optimized by Box Behnken response surface method,and the entrapment efficiency was predicted.The entrapment efficiency,particle size,polydispersity index(PDI),Zeta potential and drug loading of the optimized liposomes were evaluated.Results:The optimal prescription and preparation of Folium Rhododendri Daurici oil liposome was confirmed as follows:X1=7.28:1、X2=11.34:1、X3=9.32mg·mL-1,the encapsulation efficiency was(82.55±1.66)%,the particle size was(130.531±46)nm,the polydispersity index was 0.185±05,Zeta potential was(21.970±36)mV,the drug loading was(5.941±0.12)%.Conclusion:The Box Behnken response surface method is accurate to obtain the optimal formulation of mangrove oil liposomes,it has high precision and good prediction effect.And the preparation process of mangrove oil liposomes is stable and feasible.

Optimization of DsbA Purification from Recombinant Escherichia coli Broth Using Box-Behnken Design Methodolog

Disulfide bond formation protein A （DsbA） is one of the important helper proteins for folding in protein synthesis in vivo. In this study, purification of recombinant DsbA was investigated by examining four important factors with Box-Behnken design method, a statistic-based design of experiments. The optimal operation conditions were obtained by adopting the effectiveness coefficient method on the multi-objective problem, which takes the protein recovery, purification efficiency and throughput of ion-exchange chromatography into account. After the optimization, protein recovery of 96.8% and purity higher than 95% DsbA was achieved, and the productivity was （377.9±1.7） mg soluble DsbA per liter broth. The purified protein was identified by peptide mass fingerprinting matching the record of gil2624856, a mutant of DsbA. The DsbA was preliminarily applied to the refolding of denatured lysozyme in vitro.

The Adsorption of Pb(II)Using Silica Gel Synthesized from Chemical Bottle Waste:Optimization Using Box-Behnken Design

The adsorption of Pb(II)on silica gel synthesized from chemical glass bottle waste has been studied.The effect of independent variables(adsorbent dose,initial concentration of Pb(II),contact time,and pH)on the Pb(II)removal from water was evaluated and optimized using the Response Surface Methodology(RSM).Under optimized conditions(adsorbent dose:20 mg;contact time:30 min;initial Pb(II)concentration:120 mg.L^(−1);and pH:8),the removal of Pb(II)was 99.77%.The adsorption equilibrium data obtained from the batch experiment were investigated using different isotherm models.The Langmuir isotherm model fits the experimental data.This shows that the surface of the silica gel synthesized from chemical bottles waste was covered by a Pb(II)monolayer.XRF analysis showed that the synthesized silica gel had a SiO_(2) content of 75.63%.Amorphous silica was observed from XRD analysis.SEM-EDX characterization showed that Pb was adsorbed on the silica gel surface.SEM analysis showed that silica gel has irregular particles with a surface area of 297.08 m2.g^(−1) with a pore radius of 15.74 nm calculated from BET analysis.

Phenol contaminated municipal wastewater treatment using date palm frond biochar:Optimization using response surface methodology

Phenol is classified as an emerging contaminant which can be very toxic even at low concentrations and should be removed from wastewaters before reaching the environment.In this study date palm frond and leaf were pyrolyzed at different temperatures to identify the best adsorbent(feedstock)and pyrolysis temperature to remove phenol from aqueous solutions.Date palm frond pyrolyzed at 600℃,termed DPF600,achieved the highest phenol removal rates of 64%and adsorption capacity of 15.93 mg/g.Response surface methodology approach using Box-Behnken design was implemented to obtain the optimal pH(6),contact time(20 h)and dosage(0.1 g)for the maximum phenol adsorption.A predicted adsorption capacity was found as 16.62 mg/g which was in close agreement with the experimental adsorption capacity of 17.38 mg/g.Isotherm and kinetic models in both linear and non-linear forms indicated that Freundlich model(R^(2)=0.99,χ^(2)=0.02,RMSE=1.09)and pseudo-second order model(R^(2)=0.99,χ^(2)=0.85,RMSE=5.41)fit best the obtained experimental data.Thermodynamics calculations affirmed that the adsorption of phenol onto DPF600 biochar was endothermic and spontaneous.The point of zero charge was found to be at 6.5 for DPF600 biochar.Scanning electron microscopy coupled with energy dispersive X-ray,Fourier transform infrared spectroscopy and X-ray diffraction confirmed adsorption of phenol onto DPF600 biochar.Application of DPF600 biochar to remove phenol from synthetic primary and secondary treated wastewater samples achieved 60 and 85%removal rates and 241 mg/g and 22.28 mg/g adsorption capacities,respectively.Regeneration studies showed promising adsorption capacities indicating the efficacy of DPF600 for the removal of phenol from wastewater.

Assessment of dead layers thickness of an HPGe detector after an extended operating period using response surface methodology and Box–Behnken design

Purpose This work aims to study the increase in dead layer thickness of an HPGe N-type detector during its operational period from 2012 to 2018.Methods The dead layer was examined along three Ge-crystal surfaces,such as outer frontal,outer lateral,and inner lateral.These parameters were optimized using response surface methodology(RSM)with a Box–Behnken design(BBD).The Monte Carlo calculations using the GAMOS(Geant4-based Architecture for Medicine-Oriented Simulations)code were performed to evaluate the detector’s efficiency at different values of the inactive germanium layer.Results and conclusion The optimal combination of dead layer thickness has been identified using the desirability function approach,which is a useful tool to optimize multi-response problems.To find the variation in dead layer thickness over the operational period,the optimization procedure was reiterated for both experimental efficiencies measured in 2012 and 2018.The obtained results show that dead layers thickness has increased from 0.6141 mm to 0.7447 mm,0.0803 mm to 2.2721 mm,and 1.5012 mm to 1.6091 mm for the outer frontal,outer lateral,and inner lateral surfaces,respectively.

Optimization and characterization of nimesulide bilayer tablets by response surface methodology

The objectives of this present investigation were to develop and formulate nimesulide bilayer tablets by using different polymer combinations and fillers, to optimize the formulations for different drug release variables by orthogonal design and central composite design-surface methodology and to evaluate drug release pattern of the optimized product. The bilayer tablet containing a fast release layer（FRL） and a sustained release layer（SRL） provided an initial burst release of nimesulide, followed by the sustained release for a period of time. The optimal formulation obtained was as follows：（I） the formulation of FRL： nimesulide, 50 mg; lactose, 92 mg; starch, 22 mg; CCMC-Na, 14 mg; PVP K30, 1 mg; micronized silica gel, 1 mg; magnesium stearate, 0.9 mg; and iron oxide red, 0.1 mg; and（II） the formulation of SRL： nimesulide, 150 mg; HPMC K100LV, 26 mg; HPMC K4M, 33 mg; lactose, 54 mg; PVP K30, 1 mg; micronized silica gel, 1 mg; and magnesium stearate, 0.9 mg. According to the optimal formulation, the biphasic type of release was identified. The in vitro drug dissolution from the bilayer tablets was sustained for about 16 h after releasing 15% of drug in the first 10 min. The developed nimesulide bilayer tablets with improved efficacy can perform therapeutically better than the conventional tablets.

Fluoride removal from secondary effluent of the graphite industry using electrodialysis:Optimization with response surface methodology

Response surface methodology was utilized to model and optimize the operational variables for defluoridation using an electrodialysis process as the treatment of secondary effluent of the graphite industry. Experiments were conducted using a Box-Behnken surface statistical design in order to evaluate the effects and the interaction of the influential variables including the operational voltage, initial fluoride concentration and flow rate. The regression models for defluoridation and energy consumption responses were statistically validated using analysis of variance (ANOVA);high coefficient of determination values (R^2 = 0.9772 and R^2 = 0.9814;respectively) were obtained. The quadratic model exhibited high reproducibility and a good fit of the experimental data. The optimum values of the initial fluoride concentration, voltage and flow rate were found to be 13.9 mg/L, 13.4 V, 102.5 L/h, respectively. A fluoride removal efficiency of 99.69% was observed under optimum conditions for the treatment of the secondary effluent of the graphite industry.

Experimental design for optimization of 4-nitrophenol reduction by green synthesized CeO2/g-C3N4/Ag catalyst using response surface methodology

In this study,the enhancement of catalytic activity of ceria when modified with co-catalysts such as graphitic carbon nitride and silver was establishe d.The material was synthe sized using phytogenic combustion method,a green alternative to the traditional preparative routes.The catalyst was characterized using XRD,FTIR,SEM,EDX,XPS and TEM techniques.The synergistic effect of the composite CeO2/g-C3 N4/Ag was tested for catalytic reduction of 4-nitrophenol in the prese nce of sodium borohydride.The reaction was carried out at room tempe rature without any light source or exte rnal stirring.The individual and combined effects of four parameters,viz.,concentration of 4-NP,amount of catalyst,amount of NaBH4 and time for the reduction of reduction 4-NP were investigated using Box-Behnken design of response surface methodology(RSM).This statistical model was used to optimize the reaction conditions for maximum reduction of 4-NP.The optimum conditions for the reduction reaction are found to be 0.01 mmol/L 4-NP,15 mg catalyst,20 mg NaBH4 and 13.7 min time interval.

Optimization of Cultivation Conditions for Exopolysaccharide and Mycelial Biomass by Clitocybe sp. Using Box-Behnken Design

Response surface (RSM) methodology based on a three-level three-factor Box-Behnkendesign of experiment was used to optimize the exopolysaccharide content (EPC) and themycelium biomass in submerged cultivation by Clitocybe sp. AS 5.112. The criticalfactors selected for the investigation were cultivation temperature, time and volume ofmedium, based on the results of previous Plackett-Burman design. By analyzing theresponse surface plots, the optimum ranges of cultivation temperature, time and mediumvolume for obtaining over 1 253.00gmL-1 of EPC lie in 24.325.8℃, 9.710.2d and 76.090.0mL, respectively. While for obtaining over 8.32 mg mL-1 of dry cell weight (DCW), theabove variables would be in the range of 23.824.8℃, 9.610.3d and 71.098.0mL,respectively. By solving the inverse matrix from the quadratic regression equations, theoptimal conditions to gain 1 265.45gmL-1 of EPC were 25.0℃, 9.9d and 83.4mL, to gain8.50mg mL-1 of DCW were 24.4℃, 9.9d and 87.1mL. In order to obtain the maximum yield ofEPC and DCW at the same time, the above conditions would be 24.5℃, 9.9d and 84.7mL,respectively, in this situation, the maximum predicted EPC and DCW were 1 261.60gmL-1and 8.47mgmL-1, respectively. The experimental data under various conditions have validatedthe theoretical values.