جستجوی مقالات مرتبط با کلیدواژه « response surface methodology » در نشریات گروه « پزشکی »

At present study, the removal of p-nitrophenol (PNP) by a newly designed mesoporous organocarbon, monolayers of ß-cyclodextrine (CD) on oxidzed ordered nanoporous carbon (OX-ONC) via 1,4-phenylene diisocyanate (PDI) linking denoted as CD-ONC was optimized. Furthermore, Au-doped mesoporous carbon CMK-3 denoted as Au-OCMK-3 was synthesized by using SBA-15. Au-OCMK-3 has been studied for removal of dibenzothiphene (DBT) and carbazole (CA) from n-hexane. Also the functionalization of SBA-16 mesoporous with sulfonic acid for arsenic (As (V)) and copper (Cu (II)) removal were carried out (SBA-16-SO3H). Maximum absorption capacity of CD-ONC was 100 mg/g. Dubinin–Radushkevich isotherm was applied to describe the nature of PNP uptake and it was found that it occurred physically (E = 0.07 KJ/mol, CD-ONC). Value for Temkin’s heat of adsorption is positive for PNP (157.87 J/mol, CD-ONC). There are two physisorption models of PNP with the surface C=O groups of ONC (H-bond and dispersion effect between phenolic ring and π electrons). The overall PNP adsorption process was exothermic and spontaneous in nature according to thermodynamics parameters (free energy (ΔGo), enthalpy (ΔHo), and entropy (ΔSo)). We demonstrate that functionalization of CMK-3 with gold is possible (qm value for DBT: 15.33 mg/g and for CA: 13.00 mg/g). The adsorption capacity for As (V) on SBA-16- SO3H reaches 92.63 mg/g. The high removal of As equilibrium time of 90 minutes can be explained in terms of a strong electrostatic attraction that occurred between the SO3H and As. Maximum absorption capacity was 92.63 mg/g for As(V) was and 13.00 mg/g for Cu(II).

 The N-terminal domain of the myelin oligodendrocyte glycoprotein (MOG) has been shown to generate experimental autoimmune encephalomyelitis (EAE), an animal model of MS. A considerable amount of MOG must be accessible for EAE induction. Here, for the first time, Response Surface Methodology-Box-Behnken (RSM-BBD) was employed to identify the ideal culture conditions for causing Escherichia coli (E. coli) BL21 to overproduce the Thioredoxin-MOG (Trx-MOG) fusion protein. The RSM method is a powerful, efficient, and reliable alternative to the One-Factor-At-A-Time (OFAT) method in optimizing process variables, allowing for a smaller number of experimental runs, investigating variable interaction, and being cheaper and less time-consuming.

 Here, using the 29 experimental assays, the direct and indirect effects of factors including post-induction time, IPTGinducer concentration, pre-induction optical density, and post-induction temperature on the protein expression level content were evaluated.

 The proposed quadratic model demonstrated a significant effect of the two variables A (time) and C (temperature) on protein synthesis. An inducer concentration of 0.491 mM, the pre-induction optical density (OD600) of 0.8, and a temperature of 23 °C for 23.878 hours were found to be the best growth conditions for high yield Trx-MOG synthesis. The optimum protein concentration was attained (163.96 µg/mL) and was within the range of (200.04 µg/mL), which was the value predicted.

 The study concluded that RSM optimization effectively increased the production of Trx-MOG in E. coli, which could have the potential for large-scale fermentation.

Astragalus fasciculifolius Boiss is one of the native medicinal plants of Iran that has a special place in Iranian medicine. We investigated the phenolic compounds profile of ethanolic gum extracts, antimicrobial activity (MIC and MBC), and modeling and optimization of Clostridium perfringens growth dynamics in meat matrices. The results showed that the highest phenolic composition in the ethanolic extract was hesperidin (17.61%). Ethanolic A. fasciculifolius gum extract had antimicrobial activity. The MIC and MBC of Clostridium perfringens were reported as 156 and 78 (mg/g extract). The ethanolic gum extract caused shrinkage and changes in bacterial membranes. Dynamic modeling of bacterial growth in the meat matrix in the presence of the ethanolic A. fasciculifolius gum extract was performed as a quadratic equation. It was found that the lowest number of bacteria would be observed at 7200.8 ppm of extract, a storage time of 14.29 hours, and a storage temperature of 4.00 °C. This study showed that A. fasciculifolius gum has important active ingredients that can be used in the food, cosmetics, and drug industries.

This study aimed to produce gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the nervous system, from Lactobacillus brevis IBRC 10818 using microbial biosynthesis and ultrasonic shock. Microbial biosynthesis is one of the best production methods compared to chemical synthesis. The response surface methodology (RSM) was used to optimize and model the GABA production under the influence of four shock factors: ultrasonic intensity, ultrasonic time, incubation period, and monosodium glutamate (MSG) concentration. The shock was applied during the lag phase. The optimal conditions for maximum GABA production were predicted to be 2.98 % MSG, 70.8 h incubation time, 6.30 min shock time, and 33 kHz frequency. Under these conditions, the GABA production was 266.19 mg/L, which was close to the predicted value of 212.2 mg/L. The model prediction was suitable with a high coefficient of determination (R2=0.96).

Anthocyanins are the largest group of water-soluble plant pigments with significant health-promoting activities, and can be used as natural colorants in food systems. The overall purpose of the current study was to optimize the methanol-water solvent extraction of Roselle anthocyanin using three independent variables: extraction time (2 to 6 h), extraction temperature (20 to 40⁰C), and Roselle petal to solvent weight ratio (2 to 6 g). According to the results, the amount of extracted anthocyanin from Roselle petals ranged from 123.85 to 270.49 mg/L. An increase in extraction time, extraction temperature, and petal: solvent ratio could significantly increase the anthocyanin extraction efficiency (P≤0.05), as the highest anthocyanin content (270.490 mg/L) was obtained in the following extraction conditions: extraction temperature of 40⁰C for 4 h and petal: solvent ratio of 6. Optimal conditions for maximum anthocyanin extraction from Roselle petals were predicted to be extraction temperature of 40⁰C, extraction time of 5.71 h, and petal: solvent ratio of 6. Under these conditions, the amount of extracted anthocyanin was 266.19 mg/L, indicating the suitability of the model prediction (R2=0.96).

Several isolated species from symptomatic frozen leaves and soil produce ice nucleation proteins and have been exploited for their Ice Nucleation Activity (INA). Ice nucleation proteins can be employed as promising substances for biotechnological applications such as artificial snow-making, cryopreservation of tissues, and the condensation of ice nuclei in clouds. Considering INA has a direct relationship with bacterial growth, optimization of the culture medium seems indispensable. In this study, the INA of a newly isolated Pseudomonas sp. IRL.INP1 was evaluated. Plackett–Burman was applied for screening several cost-effective carbon and nitrogen sources affecting bacterial growth and INA. The response surface method was employed for medium optimization. Moreover, biomass, whole-cell protein, specific growth rate, and INA were estimated. Rice bran, ammonium sulfate, temperature, and olive oil had significant effects on the INA of Pseudomonas sp. IRL.INP1. Results demonstrated that 5% rice bran, 31 °C, 1.0% olive oil, and 6 g/L ammonium sulfate led to the best INA. The final optical density at 600 nm was 2.3. Also, 1.94 g/L biomass, 1.75 µg/µl whole-cell protein, and 0.26 specific growth rate (day-1) were obtained, and INA was observed after 5 sec at -5 °C. The present research is the first study using agricultural waste for INA optimization. Since rice bran is a cost-effective agro-waste and a qualified replacement for glucose, it can be utilized as a promising substrate for bacterial growth and INA.

The use of synthetic additives is one of the main approaches for preventing microbial growth and oxidative reactions in meat products. These preservatives were recently marked as unhealthy to humans; therefore, the consumers demand for fresh, natural, and negligibly processed products with lower content of artificial additives is increasing.

Experimental:  

The effect of Satureja bachtiarica Bunge essential oil (EO) and tomato powder (TP) to optimize sausage formulation with reduced nitrite content was investigated. Response surface methodology (RSM) was used to investigate the effects of different levels of EO (200-400 ppm), TP (5-15%) as Hurdles, and sodium nitrite (SN) (0-300 ppm) in sausage formulation during storage (0- 24 days). Dependent variables including residual nitrite, pH, color indices, microbial load, and hardness were investigated and finally model optimization and validation were conducted.

The results showed that residual nitrite was strongly depending on initial added nitrite and storage time (p<0.001), so the use of nitrite substituent was undeniable to have an improved sausage formulation without microbial defect. RSM represented a quadratic model for all responses except in texture which was linear and the pH and microbial load showed interaction. The optimized predicted values for SN, EO and TP were 56 ppm, 378 ppm and 5%, respectively. The model validation revealed that the results of the experiments were in good agreement with the predicted values.

Recommended applications/industries:

 The results of the present study can be useful for consideration in meat products industry to reduce the nitrite level in sausage formulation.

Production of functional recombinant antibody fragments in the periplasm of E. coli isa prerequisite step to achieve sufficient reagent for preclinical studies. Thus, the cost-effectiveand lab-scale production of antibody fragments demands the optimization of culture conditions.

The culture conditions such as temperature, optical density (OD600) at induction,induction time, and IPTG concentration were investigated to optimize the functional expressionof a phage-derived scFv molecule using a design of experiment (DoE). Additionally, the effectsof different culture media and osmolyte supplements on the expression yield of scFv wereexamined.

The developed 2FI regression model indicated the significant linear effect of theincubation temperature, the induction time, and the induction OD600 on the expression yieldof functional scFv. Besides, the statistical analysis indicated that two significant interactions ofthe temperature/induction time and the temperature/induction OD600 significantly interplay toincrease the yield. Further optimization showed that the expression level of functional scFvwas the most optimal when the cultivation was undertaken either in the TB medium or in thepresence of media supplements of 0.5 M sorbitol or 100 mM glycine betaine.

In the present study, for the first time, we successfully implemented DoE tocomprehensively optimize the culture conditions for the expression of scFv molecules in aphage antibody display setting, where scFv molecules can be isolated from a tailor-made phageantibody library known as “Human Single Fold scFv Library I.”

Opportunistic fungi are known as important causes of nosocomial infections. Since drug resistance is one of the main problems when treating the infections, many efforts have been made to develop alternative drugs – herbal compounds, in particular. Dracocephalum kotschyi is a medicinal plant widely used in traditional medicine, which also shows sufficient antifungal activities against different species of Candida. This study aimed to optimize condition for extraction of bioactives from D. Kotschyi and achieve the maximum antifungal properties by adopting response surface methodology (RSM).

A three-factor-five-level central composite rotatable design (CCRD) was employed to determine the effects of extraction time (1-12 hours), temperature (40-80°C), and plant powder to solvent (PP/S) ratio (0.2-0.8%) on well diffusion method (WDM), minimum fungicidal concentration (MFC), and minimum inhibitory concentration (MIC). The methanol extracts were prepared using Soxhlet apparatus, and the antifungal activities against ATCC 1677s Candida albicans were evaluated.

The results showed that the P values of the model for WDM, MFC, and MIC were 0.0062, 0.0111, and 0.0278, respectively. The determination coefficient for WDF, MFC, and MIC were 0.853, 0.770, and 0.721, respectively. In addition, the lack of fit for all responses was non-significant (P value ˃0.05). The optimal extraction parameters included the extraction time of 3.23 hours, PP/S ratio of 0.68 mg/ mL, and temperature of 68˚C.

In sum, RSM with CCRD was found to be an efficient method for designing and optimizing the extraction process. The optimized extracts exhibited an acceptable antifungal effect compared to the predicted effects against C. albicans.

Monascus is one of the fungi that can be used to produce red pigments with food grades. In this study, Monascus purpureus ATCC 16362 was used to produce red pigments in date waste substrates, using submerged fermentation. Response surface methodology was used to optimize three significant factors of date waste sugar concentration (20–60 g.l-1), NaCl (6–12 g.l-1) and initial pH (6–9). The, effects of independent variables on red pigment and biomass content were assessed. Concentrations of 20 g.l-1 date waste sugar and 6 g.l-1 NaCl and pH 9 resulted in the maximum yield of red pigments of 6.05±0.04 AU.ml-1 and biomass of 7.2 g.l-1. Furthermore, substrate conversion, yield of red Monascus pigments on biomass and the volumetric productivity included 82%, 10.42 AU pigment g-1 biomass and 5.36 g.l-1.day-1, respectively. Therefore, from the results of this study, date waste can be used as a low-cost substrate for the production of red pigments in large-scale studies.

 Overexpression of CD20 protein on the surface of B cells in lymphoma can be targeted by several anti-CD20 molecules. The development of accessible interactive epitopes is more favorable than the full-length transmembrane CD20 in the affinity assessment of anti-CD20 monoclonal antibodies (mAbs).

 The sequence of these epitopes was extracted, and the effects of different linker peptides and the location of histidine (His)-tag were computationally analyzed. The impact of thioredoxin (Trx)-tag on the folding of the selected construct and its interaction with rituximab was further investigated. The two final expression cassettes were expressed in Escherichia coli after optimization of culture conditions for incubation temperature, post-induction time, optical density at the induction time, and concentration of the inducer. ELISA evaluated the binding affinity of rituximab towards the recombinant proteins.

 By homology modeling studies, C-terminal His-tagged structures represented more desirable folded structures. Validation of the models revealed that CD20 extracellular domain linked by the G4S polypeptide had better stereochemical quality and structural compatibility. It was selected due to its more effective interaction with rituximab showing the highest dissociation constant of 5.8E-09M, which improved after the fusion of Trx-tag (7.1E-10M). The most influential parameters in the expression of the two selected proteins were post-induction temperature and optical density at the induction time. Homemade ELISA assays revealed a slightly higher affinity of rituximab towards the Trx-CD20 protein than the CD20/G4S molecule.

 Experimental in vitro studies confirmed the computationally calculated affinity of rituximab towards the two designed CD20 constructs. Also, the cell-based binding assessment of anti-CD20 mAbs could be substituted by the engineered extracellular domain of human CD20 protein.

The increasing trend of petroleum production in Iran and lack of proper and systematic management of waste products in the deposition of petroleum storage tanks have made the existing hydrocarbons as a major hazards to the environment. In this study, the ozonation process was used to remove the petroleum deposits.

In this experimental study, effects of pH, ozone dose, and petroleum hydrocarbons (PHCs) concentration were evaluated. In order to measure the PHCs, using the n-pentanes, the hydrocarbons were first extracted from the environment followed by detection using the GC-FID. The response surface methodology (RSM) was used to evaluate the effect of independent variables on response function.

In this study, the efficiency was calculated 45.47% in the optimal conditions of removing PHCs with respect to the optimal energy consumption for the process. Analysis of variance and regression showed that the fitted model had good agreement with the laboratory results.

The results demonstrated that the advanced oxidation process (AOP) of ozone at high pH levels could be a useful method for the degradation and reduction of heavy hydrocarbons in petroleum waste. However, regarding the energy consumption, it is suggested to use less costly reactions as pretreatment or final treatment steps.