Enhanced fatty acid storage combined with the multi-factor optimization of fermentation for high-level production of docosahexaenoic acid in Schizochytrium sp

Schizochytrium sp. hasreceived much attention for itsability to synthesize and accumulate high-level docosahexaenoic acid (DHA), which can reach nearly 40 % of total fatty acids. In this study, the titer of DHA in Schizochytrium sp. was successfully improved by enhancing DHA storage through overexpressing the diacylglycerol acyltransferase (ScDGAT2C) gene, as well as optimizing the supply of precursors and cofactors required for DHA synthesis by response surface methodology. Notably, malic acid, citric acid, and biotin showed synergistic and time-dependent effects on DHA accumulation. The maximum lipid and DHA titers of the engineered Schizochytrium sp. strain reached 84.28 ± 1.02 g/L and 42.23 ± 0.69 g/L, respectively, with the optimal concentration combination (1.62 g/L malic acid + 0.37 g/L citric acid + 8.28 mg/L biotin) were added 48 h after inoculation. This study provides an effective strategy for improving lipid and DHA production in Schizochytrium sp.

Response surface methodology to optimize the sterilization process of slightly acidic electrolyzed water for Chinese shrimp (Fenneropenaeus chinensis) and to investigate its effect on shrimp quality

Chinese shrimps are popular among consumers for their delicious taste and high nutritional value, but they are highly susceptible to deterioration due to microbial contamination with degradation of texture, color and flavor. The aim of this study was to evaluate the effects of available chlorine concentration (ACC), processing time and material-liquid ratio on the bacterial inhibition rate of shrimp treated with slightly acidic electrolyzed water (SAEW). The effective parameters were optimized by response surface methodology to the optimal bactericidal conditions: ACC 88 mg/L, processing time 12 min, and material-liquid ratio 1:4. The actual bactericidal inhibition rate of shrimp under these conditions was 37.60 %. On this basis, the quality, color difference and textural changes of shrimp treated with SAEW, sodium hypochlorite and alkaline electrolytic water were compared and investigated during storage at 4 °C. The combined results showed that the SAEW treatment could extend the shelf-life by more than 2 d.

Investigating the characteristics of biomass wastes via particle feeder in downdraft gasifier

Particle feeding plays a crucial role in the gasifier due to its effects on the efficiency and performance metrics of the thermochemical process. Investigating particle size distribution's impact on downdraft gasification reactor performance, this study delves into the significance of feedstock characteristics (moisture, volatile matter, fixed carbon, and ash contents) during the particle feeding stage. Various biomass wastes (date palm waste, olive pomace and sewage sludge) at diverse compositions and sizes are subjected to empirical determination of mass flow rates (MFR), power ratings, and storage times for each feedstock. The preheating process in the gasifier is considered, employing both an approximation and analytical solution. In addition, the influence of the equivalence ratio (ER) on the syngas yield is analyzed. The collected data reveals that for average particle size of 200 μm, the highest MFR (in g/min) are 0.518 ± 0.033, 7.691 ± 0.415, and 16.111 ± 1.050, for palm wood biomass, olive pomace and sewage sludge, respectively. Smaller particles (80 μm) led to extended storage times. Moreover, the lumped capacitance approximation method consistently underestimates preheating time, with a percentage error of 6.26%-17.08%. Response surface methodology (RSM) optimization analysis provides optimal gasification conditions for palm wood biomass, olive pomace, and sewage sludge with maximum cold gas efficiencies (CGEs) of 58.01%, 63.29%, and 52.27%. The peak conversion was attained at gasification temperatures of 1089.83 °C, 1151.93 °C, and 1102.91 °C for palm wood biomass, olive pomace, and sewage sludge, respectively. In addition, gasification equilibrium model determined optimal gasification temperatures as 1150 °C for palm biomass, 1200 °C for olive pomace, and 1150 °C for sewage sludge with respective syngas efficiencies of 59.62%, 64.13%, and 53.66%. Consequently, the examination of the dosing procedure, preheating dynamics, particle dimensions, ER, storage time, and their combined impacts offer practical insights to effectively control downdraft gasifiers in handling a variety of feedstocks.

Electrocatalysis coupled heterogeneous electro-Fenton like treatment of coal gasification wastewater using tourmaline as catalyst: process parameters and response surface

Coal gasification technology is essential for realizing clean and efficient conversion of coal, as well as for reducing carbon emissions. However, coal gasification technology is accompanied by a large amount of coal gasification wastewater that is biodegradable. In this work, tourmaline was applied as a catalyst in electro-Fenton like process for treating coal gasification wastewater. The optimal applied parameters of coal gasification wastewater were investigated as follows: current density of 90 mA cm-2, tourmaline dosage of 8 g L-1, electrode gap of 1 cm, and temperature at 25 °C; the COD removal ratio reached 91.24% after 240-min treatment. In addition, the current density and tourmaline dosage were further optimized by response surface method. The result was about current density with 82.4 mA cm-2 and catalyst with 7.57 g L-1; the predicted COD removal efficiency was 86.91%. Under the optimal parameters the actual COD removal efficiency was 88.25% a little high than the predicted value. To explore the reusability of tourmaline as Fenton reaction catalyst, five cycles of experiments were carried out. The result demonstrated that tourmaline could be used as catalyst for treating coal gasification wastewater by electro-Fenton like process.

Optimization of ultrasonic-assisted supramolecular solvent microextraction of coumarins from Cortex fraxini using response surface methodology combined with artificial neural network-genetic algorithm

A simple, fast, and efficient ultrasonic-assisted supramolecular solvent microextraction combined with high performance liquid chromatography method was developed for the determination of coumarins in Cortex fraxini, including esculin, esculetin and fraxetin. In this study, a novel supramolecular solvent was prepared with 1-octanol, tetrahydrofuran and water for the first time, and its composition, viscosity, density, structure, and micromorphology were characterized. The prepared supramolecular solvent exhibited vesicular structures and had the characteristics of low viscosity. Through single-factor experiments, response surface methodology and artificial neural network-genetic algorithm, the optimal extraction conditions were obtained as follows: NaCl concentration of 1 mol mL-1, pH value of 10, solid-liquid ratio of 10:1, vortex time of 30 s, ultrasonic power of 100 W, ultrasonic temperature of 60 °C, ultrasonic time of 15 min, centrifugation speed of 5000 rpm, and centrifugation time of 1 min. The results demonstrated that the artificial neural network model exhibited maximum R-values of 0.98703, 0.97440, 0.99836, and 0.95447 for training, testing, validation, and all dataset, respectively. The minimum mean square errors were 0.75, 10.15, 1.99, and 2.63, respectively. This indicated that the predicted values were almost consistent with the actual values. Under the optimal conditions, the total extraction yields of target analytes reached 2.80 %. The calibration curves for each analyte exhibited excellent linearity within the linear range (r > 0.9993). The limits of detection and quantification ranged from 4.87 to 6.55 ng mL-1 and 16.24 to 21.84 ng mL-1, respectively. The recoveries ranged from 98.71 % to 111.01 % with relative standard deviations of less than 3.6 %. The present method had the advantages of short extraction time (15 min) and less solvent consumption (0.5 mL). The prepared supramolecular solvent was proved to have great potential in extracting coumarins from medicinal plants.

Adsorption performance of Ni(II) by KOH-modified biochar derived from different microalgae species

Microalgae biochar is potential adsorbents to remove heavy metals from wastewater due to abundant functional groups, high porosity and wide sources, but performance is not fully developed since it depends on microalgae species attributing to distinct morphology and biomass compositions. Here, two microalgae species Chlorella Pyrenoidosa and Scenedesmus Obliquus were used for biochar preparation via KOH-modification, biochar properties and their influences on Ni(II) adsorption were investigated. Ni(II) adsorption performances responding to biochar properties and operating conditions were upgraded via progressive optimization and response surface methodology. Together, adsorption isotherms and kinetics were analyzed to obtain significant factors for Ni(II) removal. As results, 100 % of Ni(II) removal was achieved under 100 mg/L initial Ni(II) concentration as pH was higher than the biochar zero-charge point of 6.87 with low biochar dosage (0.5 g/L), which provides an efficient approach for heavy metal removal from wastewater with microalgae biochar.

The effects of Trametes versicolor fermented Rosa roxburghii tratt and coix seed quild on the nutrition, sensory characteristics and physical and chemical parameters of yogurt

Trametes versicolor can produce aromatic flavor in growth and development, widely used in food fermentation. This study used a One-Factor-at-a-Time (OFAT) test and response surface analysis to study the optimum fermentation parameters of Rosa roxburghii tratt and coix seed yogurt by Trametes versicolor. The best fermentation process is as follows: skim milk powder 17 %, sucrose content 4 %, Rosa roxburghii tratt and coix seed liquid 36 %, fermentation temperature 39 °C, inoculum 2 %, strain ratio 2:1:1(LB12: BLH1: Q-1), fermentation time 9.5 h. Under this fermentation process, the sensory score was 82.11, the contents of vitamin C, GABA, and total live bacteria in this yogurt were 13.89, 2.58, and 1.02 times higher than in common yogurt. Correlation analyses showed a significant contribution of the leavening agent to the GABA content of yogurt. This study provides a foundation for producing Rosa roxburghii tratt and coix seed yogurt with high sensory and nutritional value.

Ultrasound assisted wall-breaking extraction and primary structures, bioactivities, rheological properties of novel Exidia yadongensis polysaccharide

New natural multifunctional polysaccharide and its innovatory extraction technology may be urgently needed for food industries. Our aims were to establish new extraction method and investigate the primary structures, bioactivities and rheological properties of novel E. yadongensis polysaccharide (EYP). Ultrasound assisted mechanical wall-breaking extraction (MAUE) was successfully established for the EYP extraction from a new E. yadongensis. Based on the MAUE with RSM, the polysaccharide yield of 17.92 ± 0.56 % with the optimal parameters of five extraction factors were obtained, and current MAUE was characterized by its high yield, low extraction temperature and short ultrasound time. After the isolation and purification, the EYP as a protein-bound polysaccharide was obtained. FT-IR and NMR analysis showed that the main backbone of the EYP comprised of (1 → 4)-β-D-glucopyranosyl and (1 → 6)-ɑ-D-mannopyranosyl groups; EYP exhibited significant antioxidant, antibacterial, antitumor, antidiabetic activities, and good viscoelastic properties in low pH solutions (P < 0.05). The EYP may be used as a natural functional and cohesive agent in food industries.

Optimizing the photon ratio of red, green, and blue LEDs for lettuce seedlings: a mixture design approach

BACKGROUND

Light control technology has been developed and studied for decades in controlled environment agriculture (CEA) for successful crop production. The effects of the light spectrum on plant growth can vary because plants have spectral specific responses, and mixed light elicits interactive combination effects. Response surface methodology (RSM) can be utilized with the design of experiments to optimize a response influenced by multiple inputs with limited data. In this study, we aimed to identify the optimal photon ratio in combination of red (R), green (G), and blue (B) light-emitting diodes (LEDs) for growing lettuce seedlings using RSM and a seedling-indicating parameter by performing a similarity analysis of response surfaces that elucidated the response tendency of different factors, such as light quality.

RESULTS

The highest shoot fresh weight was obtained from the R treatment (red LED 100%) at the end of the seedling stage. However, the RGB141 (photon ratio of R:G:B = 1:4:1) treatment during the seedling stage resulted in the highest shoot fresh weight at the final harvest. The value of the leaf area multiplied by the leaf chlorophyll concentration (SPAD) was selected as the seedling-indicating parameter. The optimal RGB photon ratio that maximized this parameter was R:G:B = 30.6:44.0:25.4, and this ratio was verified by conducting identical cultivation experiments. During the first 6 days after transplanting, SPAD gradually increased in R-treated seedlings, while the optimal treatment maintained the value at a higher constant level, which supported our result of shoot fresh weight at harvest.

CONCLUSIONS

Thus, we confirmed that the mixture design method allowed us to optimize the combined RGB photon ratios for the seedling stage in order to maximize the growth index of mature lettuce plants and to select an appropriate seedling-indicating parameter that represents the final harvest results to benefit crop production in CEA.

Numerical optimization of hydrothermal liquefaction process for the production of bio-oil and bio-char from Citrus maxima peel waste and product characterization

This research study aims to potential utilization of Citrus maxima peel waste and optimize the hydrothermal liquefaction process for the production of bio-oil (BO) and bio-char (BC). The effect of several HTL processing variables on BO yield (%) and BC yield (%), including temperature, retention period, and slurry concentration, has been examined using central composite design (CCD) (a three-level three-factor design). The optimized values of HTL process variables were found to be 240 °C (temperature), 52 min (retention time), and 7% (slurry concentration) and the corresponding responses were 5.794% (BO yield) and 29.450% (BC yield). The values obtained from the RSM-CCD model as the predicted values agreed with the experimental values (5.93% and 30.14%). Further the BO and BC obtained under optimized conditions and CPP were analyzed to identify the variations by 1H-NMR, GC-MS, FT-IR, and CHNO-S.

Standardized ileal digestible tryptophan and lysine affects the eating and sleeping behavior of 15-30 kg barrows

The objective of this study was to evaluate the effect of standardized ileal digestible (SID) tryptophan (Trp) and lysine (Lys) levels on eating and sleeping behavior and the respective feed intake of barrows. Sixty-four pigs, averaging 15.00 ± 1.63 kg of initial body weight, were used and distributed in a randomized blocks design, in a 4 × 4 factorial scheme, consisting of four levels of SID Trp (0.155, 0.185, 0.215, 0.245%) and four levels of SID Lys (0.972, 1.112, 1.252, and 1.392%). Behavior evaluation was performed by an instantaneous sampling using 10-min intervals during 24 h, at each 7 days (days 7, 14, and 21), and each day was divided into four times of 6 h each one (08:30-14:20, 14:30-20:20, 20:30-02:20, and 02:30-08:20 h), during all the experimental period, yielding a total of 3 × 24 h behavior recordings (72 h) × 6 10-min intervals, totalizing 432 observations per animal. Data were analyzed by classifying behavior into eating or sleeping. All these behaviors were measured in order to obtain the estimated frequency of the eating and sleeping behaviors. Changes were observed (P<0.05) for all the behavioral parameters during the starting phase. SID Trp and SID Lys showed an interactive positive effect on the estimated frequency of eating behavior, and mainly SID Trp increased the estimated frequency of the sleeping behavior of starting pigs in the nocturnal time. Pig diets with increasing levels of SID Trp and SID Lys until 0.245 and 1.392%, respectively, increased the average daily feed intake, and the interaction of the amino acids increased the estimated frequency of eating behavior during all the starting phase, and mainly the increasing levels of SID Trp increased the estimated frequency of sleeping behavior of pigs from the middle to the end of the starting phase, from 2:30 to 8:20 h.

Preparation and comprehensive characterization of C16MImCl/MT for adsorbing cationic dyes

Dyeing wastewater in various industries poses a great threat to the environment. Montmorillonite (MT) is widely used in wastewater treatment because of its abundant reserves and strong exchange capacity. However, natural MT has low affinity for organic pollutants and needs to be organically modified. In order to improve the adsorption capacity of MT to cationic dyes [Congo red (CR)], using ionic liquid [1-hexadecyl-3-methylimidazolium chloride (C₁₆MImCl)] as organic modifier, the optimal preparation process of C₁₆MImCl/MT was determined by response surface methodology. The C₁₆MImCl/MT was comprehensively characterized by utilizing the techniques of XRD, FTIR, TG, BET, SEM, and molecular dynamics simulation. All the research results showed that C₁₆MImCl is successfully inserted into the layers of MT, and the basal interplanar spacing and average pore size of MT are obviously increased. The C₁₆MImCl/MT is a mesoporous material, which shows strong adsorption capacity for CR, and its CR unit adsorption capacity (CRUAC) could reach 940.200 mg/g, which is about three times that of magnetic graphene oxide and bentonite/expanded graphite.

Ultrasonic-microwave-assisted extraction for enhancing antioxidant activity of Dictyophora indusiata polysaccharides: The difference mechanisms between single and combined assisted extraction

The purpose of this study is to investigate the effects of different extraction methods (hot water-assisted extraction (HWE), microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), and ultrasonic-microwave- assisted extraction (UAME)) on the yield, chemical structures and antioxidant activity of Dictyophora indusiata polysaccharides (DPs). The research results showed that UMAE treatment had greater degree of damage to the cell wall of DPs and better comprehensive antioxidant capacity. Different extraction methods had no obvious effect on the types of glycosidic bonds and sugar rings, similar chemical composition and monosaccharide composition, with different absolute molecular weight (Mw) and molecular conformation. In particular, DPs for UMAE method had the highest polysaccharides yield, which was related to the conformational stretching and degradation avoidance of DPs in the higher molecular weight components under the simultaneous action of microwave and ultrasonic. These findings suggest that the UMAE technology has good potential for modification and application of DPs in the functional food industry.

Optimization of cacao beans fermentation by native species and electromagnetic fields

Acid and bitter notes of the cocoa clone Cacao Castro Naranjal 51 (CCN 51) negatively affect the final quality of the chocolate. Thence, the fermentative process of cocoa beans using native species and electromagnetic fields (EMF) was carried out to evaluate the effect on the yield and quality of CCN 51 cocoa beans. The variables magnetic field density (D), exposure time (T), and inoculum concentration (IC) were optimized through response surface methodology to obtain two statistically validated second-order models, explaining 88.39% and 92.51% of the variability in the yield and quality of the beans, respectively. In the coordinate: 5 mT(D), 22.5 min (T), and 1.6% (CI), yield and bean quality improved to 110% and 120% above the control (without magnetic field). The metagenomic analysis showed that the changes in the microbial communities favored the aroma profile at low and intermediate field densities (5-42 mT) with high yields and floral, fruity, and nutty notes. Conversely, field densities (80 mT) were evaluated with low yields and undesirable notes of acidity and bitterness. The findings revealed that EMF effectively improves the yield and quality of CCN 51 cocoa beans with future applications in the development and quality of chocolate products.

Data from the batch adsorption of ciprofloxacin and lamivudine from synthetic solution using jamun seed (Syzygium cumini) biochar: Response surface methodology (RSM) optimization

This dataset expresses the experimental data on the batch adsorption of ciprofloxacin and lamivudine from synthetic solution using jamun seed (JS) (Syzygium cumini) biochar. Independent variables including concentration of pollutants (10-500 ppm), contact time (30-300 min), adsorbent dosage (1-1000 mg), pH (1-14) and adsorbent calcination temperature (250,300, 600 and 750 °C) were studied and optimized using Response Surface Methodology (RSM). Empirical models were developed to predict the maximum removal efficiency of ciprofloxacin and lamivudine, and the results were compared with the experimental data. The removal of polutants was more influenced by concentration, followed by adsorbent dosagage, pH, and contact time and the maximum removal reached 90%.

Statistical optimization and characterization of fucose-rich polysaccharides extracted from pumpkin (Cucurbita maxima) along with antioxidant and antiviral activities

Biologically active phytochemicals from pumpkin reveal versatile medical applications, though little is known about their antiviral activity. The fucose-rich polysaccharide extraction conditions were optimized through Box-Behnken design and purified by column chromatography. The purified fucose-rich polysaccharide was characterized through SEM, FT-IR, ¹H NMR, XRD, TGA, and GS-MS. The analysis results revealed an irregular and porous surface of the purified polysaccharide with high fucose, rhamnose, galactose, and glucose contents. The tested fucose-rich polysaccharides revealed significant antioxidant and anti-inflammatory activity at very low concentrations. The purified fucose-rich polysaccharides exerted a broad-spectrum antiviral activity against both DNA and RNA viruses, accompanied by high safety toward normal cells, where the maximum safe doses (EC₁₀₀) were estimated to be about 3-3.9 mg/mL for both Vero and PBMC cell lines. Treatment of HCV, ADV7, HSV1, and HIV viruses with the purified polysaccharides showed a potent dose-dependent inhibitory activity with IC₅₀ values of 95.475, 20.96, 5.213, and 461.75 μg/mL, respectively. This activity was hypothesized to be through inhibiting the viral entry in HCV infection and inhibiting the reverse transcriptase activity in HIV. The current study firstly reported the antioxidant, anti-inflammatory, and antiviral activities of Cucurbita maxima fucose-rich polysaccharide against several viral infections.

Modeling biosurfactant production from agroindustrial residues by neural networks and polynomial models adjusted by particle swarm optimization

Biosurfactants are molecules with wide application in several industrial processes. Their production is damaged due to inefficient bioprocessing and expensive substrates. The latest developments of strategies to improve and economize the biosurfactant production process use alternative substrates, optimization techniques, and different scales. This paper presents a study to compare the performances of classical (polynomial models) and modern tools, such as artificial intelligence to aid optimization of the alternative substrate concentration (alternative based on beet peel and glycerol) and process parameters (agitation and aeration). The evaluation was developed in two different scales: Erlenmeyer flask (100 mL) and bioreactor (7 L). The intelligent models were implemented to verify the ability to predict the emulsification index and biosurfactant concentration in smaller scale and the biosurfactant concentration and the superficial tension reduction (STR) in bigger scale, resulting in four different situations. The overall results of the predictions led to artificial neural networks as the best performing modeling tool in all four situations studied, with R² values ranging from 0.9609 to 0.9974 and error indices close to 0. Also, four different models (Wu, Contois, Megee, and Ghose-Tyagi) were adjusted by particle swarm optimization (PSO) in order to describe the kinetics of biosurfactant production. Contois model was the only one to present R² ≥ 0.97 for all monitored variables. The findings described in this work present an adjusted model for the prediction of biosurfactant production and also state that the most adjusted kinetic model for further studies on this process is Contois model, leading to the conclusion that biomass growth is limited by a single substrate, considering only glucose.

Contrasting toxicity of polystyrene nanoplastics to the rotifer Brachionus koreanus in the presence of zinc oxide nanoparticles and zinc ions

Emerging contaminants such as nanoplastics and nanoparticles likely experience similar environmental behaviours, fate and effects but our knowledge of their combined toxicity is scanty. This study, therefore, investigated the joint toxicity of polystyrene nanoplastics (PNPs) and zinc oxide nanoparticles (ZnO-NPs) to an ecologically important rotifer Brachionus koreanus, and compared with the joint toxicity of PNPs and Zn ions (Zn-IONs from ZnSO₄·7H₂O). With increasing concentration, ZnO-NPs formed significant agglomeration with PNPs for up to 1.3 times of the original hydrodynamic size of ZnO-NPs, alongside doubling in their sedimentation and thereby losing 58% of their released Zn ions. In contrast, the availability of Zn-IONs was less affected by the agglomeration and sedimentation of PNPs, with only a loss of 18% of Zn ions at the highest concentration of PNPs. Consequently, as suggested by Concentration Addition and Independent Action models and the Model Deviation Ratios, ZnO-NPs and PNPs exerted an antagonistic interaction whereas Zn-IONs and PNPs exhibited an additive effect. We also advocate the use of the Nonparametric Response Surface method, which is more useful to predict the toxicity of chemical mixtures with interacting effects. Our findings suggested a potential difference between particle-particle and particle-ion interactions, especially at higher test concentrations, which may eventually affect their toxicity. We, therefore, call for a more systematic evaluation of commonly coexisting chemical mixtures which consist of nanoplastics and manufactured nanomaterials.

Optimization of the Duration and Intensity of UV-A Radiation to Obtain the Highest Free Phenol Content and Antioxidant Activity in Sprouted Sorghum (Sorghum bicolor L. Moench)

Technologies such as UV-A radiation applied to sprouted sorghum can stimulate the synthesis or release of phenolic compounds. Since the optimal conditions for stimulating the formation of these compounds in sorghum sprouts are unknown, we used the response surface methodology to identify the optimal conditions of irradiation duration and intensity to obtain the highest free phenol content and antioxidant activity in sprouted sorghum. The results showed that, compared with nonirradiated sorghum sprouts, sprouts irradiated under the optimal duration of 11.7 h and the optimal intensity of 5.4 µW/cm² had a significantly higher phenol content (26.3%) and antioxidant activity as measured by DPPH (28.3%) and TEAC (21.1%) assays. Our findings suggest that UV-A radiation can help develop sorghum sprouts with high biological potential that can be used to produce healthy foods for human consumption.

Co/La modified Ti/PbO2 anodes for chloramphenicol degradation: Catalytic performance and reaction mechanism

Chloramphenicol (CAP) is widely used in daily life, and its abuse hurts human health, so a suitable method is needed to solve the problem. In this study, the Ti/PbO₂ electrodes prepared by the electroplating method were characterized. The CAP degradation effect and mechanism were investigated. It was shown that the electrode surface had a dense plating with a characteristic peak of β-PbO₂ as the active component. The electrode had an oxygen precipitation potential of 1.695 V and a corrosion potential of 0.553 V, and a long service life (505.4 d). The degradation of CAP at Ti/PbO₂ electrode followed a first-order kinetic reaction. The optimal degradation conditions (current density of 12.97 mA cm^-2, electrolyte concentration of 50 mM, and solution pH of 6.38) were obtained by the response surface curve method. The degradation rate of CAP was 99.0% at 60 min. The results showed that the reactive groups leading to CAP degradation were mainly ·OH and SO₄^2-, and only a tiny portion of CAP was directly oxidized on the electrode surface. The addition of Cl^- favored the degradation of CAP, but reduced the mineralization rate. LC-MS analysis showed that ·OH mainly attacked the asymmetric centers (C1, C2) of weakly bound hydrogen atoms, resulting in underwent addition and substitution reactions. CAP was converted into two substances with m/z = 306 and m/z = 165. Finally, inorganic substances such as CO₂ and H₂O were generated. This study provided a new idea for preparing Ti/PbO₂ electrode with high performance and the safe and efficient degradation of CAP.

Sources of PM2.5 and its responses to emission reduction strategies in the Central Plains Economic Region in China: Implications for the impacts of COVID-19

The Central Plains Economic Region (CPER) located along the transport path to the Beijing-Tianjin-Hebei area has experienced severe PM_2.5 pollution in recent years. However, few modeling studies have been performed on the sources of PM_2.5, especially the impacts of emission reduction strategies. In this study, the Nested Air Quality Prediction Model System (NAQPMS) with an online tracer-tagging module was adopted to investigate source sectors of PM_2.5 and a series of sensitivity tests were conducted to investigate the impacts of different sector-based mitigation strategies on PM_2.5 pollution. The response surfaces of pollutants to sector-based emission changes were built. The results showed that resident-related sector (resident and agriculture), fugitive dust, traffic and industry emissions were the main sources of PM_2.5 in Zhengzhou, contributing 49%, 19%, 15% and 13%, respectively. Response surfaces of pollutants to sector-based emission changes in Henan revealed that the combined reduction of resident-related sector and industry emissions efficiently decreased PM_2.5 in Zhengzhou. However, reduced emissions in only the Henan region barely satisfied the national air quality standard of 75 μg/m³, whereas a 50%-60% reduction in resident-related sector and industry emissions over the whole region could reach this goal. On severely polluted days, even a 60% reduction in these two sectors over the whole region was insufficient to satisfy the standard of 75 μg/m³. Moreover, a reduction in traffic emissions resulted in an increase in the O₃ concentration. The results of the response surface method showed that PM_2.5 in Zhengzhou decreased by 19% in response to the COVID-19 lockdown, which approached the observed reduction of 21%, indicating that the response surface method could be employed to study the impacts of the COVID-19 lockdown on air pollution. This study provides a scientific reference for the formulation of pollution mitigation strategies in the CPER.

Response surface methodology (RSM) to evaluate both the extraction of triterpenes and sterols from jackfruit seed with supercritical CO2 and the biological activity of the extracts

Jackfruit seeds are an underestimate residue having important biological activity such as anti-inflammatory, cytotoxicity and antimicrobial effects. However few researches have been done for this material using alternative extraction technologies, so this study aimed to evaluate the extraction of triterpenes and sterols from jackfruit seed by applying high- and low-pressure techniques. Response surface methodology (RSM) was used to determine the best conditions of pressure, temperature and CO2 flow rate for extraction with supercritical CO2. The yield and profile of these compounds were compared with the low pressure technique, which was considered as a reference. In vitro biological tests of anti-inflammatory activity and cytotoxicity in L929 and RAW 264.7 cells were also performed. The best extraction conditions in SFE for sterols were 40 °C/20 MPa/4 mL min-1 (0.832 ± 0.007 mgSR g-1 sample) and 40 °C/20 MPa/3 mL min-1 (0.800 ± 0.009 mgSR g-1 sample), for triterpenes were 50 °C/12 MPa/4 mL min-1 (1.501 ± 0.004 mgTT g-1 sample) and 45 °C/9.3 MPa/3.5 mL min-1 (1.485 ± 0.004 mgTT g-1 sample). No cytotoxic activity was detected in L929 cells in the extracts obtained from ethanol up to concentration of 100 μg mL-1 of extract. The Pearson's coefficient indicated that the reduction in cell viability was related to the concentration of triterpenes. Anti-inflammatory assays showed that some extracts could inhibit the inflammatory action induced in RAW 264.7 cells at concentration of 30 μg mL-1 of extract. Our results justify the further exploration of these characteristics to obtain natural products for the pharmaceutical and food industries.

NOx emission from the combustion of mixed fuel pellets of Fenton/CaO-conditioned municipal sludge and rice husk

Sludge incineration technology is facing the problem of gaseous pollutant discharge. The control of NOx emissions is the key to reducing the impact of sludge combustion on environmental pollution. In this study, Fenton/CaO was used to condition municipal sludge, which was subsequently mixed with rice husk to fabricate briquette fuel for combustion experiments. The effects of the conditioner dosages, mass ratios of the rice hull to sludge, and the combustion temperatures on NO_x emissions from briquette combustion were studied. The results showed that the NO_x emissions decreased with increasing doses of conditioned sludge. In addition, with an increase in the rice husk ratio in the briquette, the NO_x emissions decreased and the conversion rate increased. Additionally, with an increasing combustion temperature, the combustion of molded fuel became more complete. The NO_x emission of conditioned sludge combustion was reduced by approximately 1.3 times compared with that of the sludge alone. Using the response surface methodology, the optimized conditions were obtained as follows: the rice husk mixing ratio is 43.8%, the Fenton/CaO conditioner dosage is 220 mg/g, and the temperature is 829 °C. The minimum NO_x emission concentration was predicted to be 0.845 mg/g. The NO_x emission laws observed from the combustion of mixed fuel pellets are believed to provide basic data for a new sludge treatment method.

Optimal extraction, purification and antioxidant activity of total flavonoids from endophytic fungi of Conyza blinii H. Lév

Background

Flavonoids are widely used in the market because of their antibacterial, antiviral, and antioxidant activities. But the production speed of flavonoids is limited by the growth of plants. CBL9 (Chaetomium cruentum) is a flavonoid-producing endophytic fungi from Conyza blinii H. Lév, which has potential to produce flavonoids.

Methods

In this study, we isolated total flavonoids from endophytic fungus CBL9 of Conyza blinii H. Lév using macroporous resin D101. The process was optimized by response surface and the best extraction process was obtained. The antioxidant activities of total flavonoids were analyzed in vitro.

Results

It was found that the best parameters were 25 °C pH 2.80, 1.85 h, and the adsorption ratio reached (64.14 ± 0.04)%. A total of 60% ethanol was the best elution solvent. The elution ratio of total flavonoid reached to (81.54 ± 0.03)%, and the purity was 7.13%, which was increased by 14.55 times compared with the original fermentation broth. Moreover its purity could rise to 13.69% after precipitated by ethanol, which is very close to 14.10% prepared by ethyl acetate extraction. In the antioxidant research, the clearance ratio of L9F-M on DPPH, ABTS, •OH, •O²⁻, (96.44 ± 0.04)% and (75.33 ± 0.03)%, (73.79 ± 0.02)%, (31.14 ± 0.01)% at maximum mass concentration, was higher than L9F.

Conclusion

The result indicated using macroporous resin in the extraction of total flavonoid from endophytic fungus is better than organic solvents with higher extraction ratio, safety and lower cost. In vitro testing indicated that the flavonoid extracted by macroporous resin have good antioxidant activity, providing more evidence for the production of flavonoid by biological fermentation method.

A finite element-guided mathematical surrogate modeling approach for assessing occupant injury trends across variations in simplified vehicular impact conditions

A finite element (FE)-guided mathematical surrogate modeling methodology is presented for evaluating relative injury trends across varied vehicular impact conditions. The prevalence of crash-induced injuries necessitates the quantification of the human body's response to impacts. FE modeling is often used for crash analyses but requires time and computational cost. However, surrogate modeling can predict injury trends between the FE data, requiring fewer FE simulations to evaluate the complete testing range. To determine the viability of this methodology for injury assessment, crash-induced occupant head injury criterion (HIC₁₅) trends were predicted from Kriging models across varied impact velocities (10-45 mph; 16.1-72.4 km/h), locations (near side, far side, front, and rear), and angles (-45 to 45°) and compared to previously published data. These response trends were analyzed to locate high-risk target regions. Impact velocity and location were the most influential factors, with HIC₁₅ increasing alongside the velocity and proximity to the driver. The impact angle was dependent on the location and was minimally influential, often producing greater HIC₁₅ under oblique angles. These model-based head injury trends were consistent with previously published data, demonstrating great promise for the proposed methodology, which provides effective and efficient quantification of human response across a wide variety of car crash scenarios, simultaneously. This study presents a finite element-guided mathematical surrogate modeling methodology to evaluate occupant injury response trends for a wide range of impact velocities (10-45 mph), locations, and angles (-45 to 45°). Head injury response trends were predicted and compared to previously published data to assess the efficacy of the methodology for assessing occupant response to variations in impact conditions. Velocity and location were the most influential factors on the head injury response, with the risk increasing alongside greater impact velocity and locational proximity to the driver. Additionally, the angle of impact variable was dependent on the location and, thus, had minimal independent influence on the head injury risk.

A novel magnesium-rich tricalcium aluminate for simultaneous removal of ammonium and phosphorus: Response surface methodology and mechanism investigation

Coexisting ammonium (NH₄⁺-N) and phosphate (PO₄^3--P) in wastewater is one of the main causes of eutrophication, which poses severe risks to aquatic ecosystem and human health worldwide. Herein, magnesium-rich tricalcium aluminate (Mg/C₃A), which was constructed by incorporating Mg into cement-based material C₃A via solid-state reaction, was employed in the simultaneous removal of NH₄⁺-N and PO₄^3--P. Considering the wastewater with unbalanced N/P ratio and fluctuant pH, the effect of multiple factors (Mg/C₃A dosage, pH, initial contaminant concentration, and temperature) on the removal of both ions were systematically investigated by employing response surface methodology technique. The results demonstrated that the impact order of the factors on the NH₄⁺ removal by Mg/C₃A was: temperature > Mg/C₃A dosage > initial NH₄⁺ concentration > pH > initial PO₄^3- concentration; the impact order on the PO₄^3- removal was: initial PO₄^3- concentration > Mg/C₃A dosage > temperature > pH > initial NH₄⁺ concentration. The maximum removal amount of NH₄⁺ (54.13 mg g^-1) and PO₄^3- (56.47 mg g^-1) were obtained at: Mg/C₃A dosage = 3 g L^-1, initial NH₄⁺ concentration = 160 mg L^-1, initial PO₄^3- concentration = 160 mg L^-1, temperature = 308 K, and pH = 7. In addition, the possible interactive influence mechanisms were elucidated in depth. Mg²⁺ played a major role in the PO₄^3- removal by forming struvite (MgNH₄PO₄·6H₂O) and newberyite (MgHPO₄·3H₂O). OH^- released from Mg/C₃A hydration mainly contributed to NH₄⁺ removal. This work showed that Mg-rich C₃A is a promising candidate for simultaneous removal of NH₄⁺ and PO₄^3-, shedding light on practical water remediation.

Optimize the preparation of Fe3O4-modified magnetic mesoporous biochar and its removal of methyl orange in wastewater

In this paper, Eichhornia Crassipes stems were used as biomass feedstock, and Fe²⁺ was used as the precursor solution to prepare Fe₃O₄-modified magnetic mesoporous biochar (Fe₃O₄@BC). By using Box-Behnken design (BBD) response surface methodology, the influences of three preparation parameters (X₁ = Fe²⁺ concentration, X₂ = pyrolysis temperature and X₃ = pyrolysis time) on the adsorption of methyl orange (MO) by Fe₃O₄@BC were investigated, and a reliable response surface model was constructed. The results show that X₁X₂ and X₁X₃ have a significant influence on the adsorption of MO by Fe₃O₄@BC. The surface area and pore volume of Fe₃O₄@BC are controlled by all preparation parameters. The increase of pyrolysis time will significantly reduce the -OH on the surface of Fe₃O₄@BC and weaken its MO adsorption capacity. Through the numerical optimization of the constructed model, the optimal preparation parameters of Fe₃O₄@BC can be obtained as follows: Fe²⁺ concentration = 0.27 mol/L, pyrolysis temperature = 405 °C, and pyrolysis time = 3.2 h. The adsorption experiment shows that the adsorption of Fe₃O₄@BC to MO is a spontaneous exothermic process, and the adsorption capacity is maximum when pH = 4. The adsorption kinetics and adsorption isotherms of Fe₃O₄@BC to MO conform to the pseudo-second-order kinetics and Sips model, respectively. Mechanism analysis shows that electrostatic interaction and H bond formation are the main forces for Fe₃O₄@BC to adsorb MO. This research not only realizes a new way of resource utilization of Eichhornia Crassipes biomass but also enriches the preparation research of magnetic biochar.

Dietary branched-chain amino acid assessment in broilers from 22 to 35 days of age

Background

Valine and isoleucine are similar in chemical structure and their limitation in broiler chicken diets. To evaluate their limitation and interactive effects, multivariate assessment nutrition studies for the branched-chain amino acids (BCAA) are needed. A three level (− 1, 0, + 1), three-factor Box-Behnken design study was conducted to assess dietary BCAA ratios to lysine of 65, 75, and 85 for valine, 58, 66, and 74 for isoleucine, and 110, 130, and 150 for leucine in male and female Lohman Indian River broilers from 22 to 35 d of age.

Results

Live performance of male broilers was not affected by BCAA level. However, male broilers fed increasing isoleucine had improved (P = 0.07) carcass yield as leucine and valine were reduced. Female broilers had improved body weight gain (P = 0.05) and feed conversion (P = 0.003) when leucine and isoleucine were at their lowest levels, independent of valine, but increasing leucine impaired live performance and warranted concomitant increases in isoleucine to restore responses. Increasing dietary isoleucine and valine in female broilers increased breast meat yield (P = 0.05), but increasing leucine tended to diminish the response.

Conclusion

The female Lohman Indian River broiler is more sensitive to BCAA diet manipulation than males. Specifically, as dietary leucine is increased in female broilers, dietary isoleucine increases were needed to offset the negative effects. Both increases in dietary valine and isoleucine improved breast meat yield in female broilers, but only when birds were fed the lowest dietary leucine.

Green coagulants recovering Scenedesmus obliquus: An optimization study

The recovery of microalgae by means of coagulation-flocculation is efficient, simple and low operating costs. The addition of coagulants makes it possible to destabilize the microalgae surface loads and recover their biomass. Chemical coagulants can contaminate the environment and negatively affect human health. Thus, the exploration of natural coagulants, such as Moringa oleifera and Guazuma ulmifolia, are innovative. Thus, this study aimed to evaluate the efficiency of biomass separation from the microalgae Scenedesmus obliquuos by means of coagulation-flocculation. M. oleifera and G. ulmifolia were used in order to optimize the variables dose, pH and settling time, through a central composite rotational design, which presented recovery efficiencies above 80.0% and 60.0%, respectively. In relation to M. oleifera, optimum regions were obtained for biomass recovery at both pH 4.0 with a dose of 40.0 mg L^-1 and pH 9.0 with a dose of 80.0 mg L^-1, both in 30 min of settling times. For G. ulmifolia, an optimum dose of 30.0 mg L^-1 at pH 4.0 with a 3 min settling time demonstrated that this new coagulant for microalgae recovery has potential for application. Thus, these natural coagulants are promising and can be used in coagulation-flocculation to recover biomass from Scenedesmus obliquuos and, thus, minimize the use of synthetic or metallic products.

In-situ fabrication of a spherical-shaped Zn-Al hydrotalcite with BiOCl and study on its enhanced photocatalytic mechanism for perfluorooctanoic acid removal performed with a response surface methodology

Perfluorooctanoic acid (PFOA), a widely used compound, is harmful to the environment and human health. In this study, a facile one pot solvothermal method of integrating BiOCl with Zn-Al hydrotalcite to form spherical-shaped BiOCl/Zn-Al hydrotalcite (B-BHZA) sample is reported. The characteristics and main factors affecting photocatalytic PFOA and photocatalytic mechanism of BiOCl/Zn-Al hydrotalcite (B-BHZA) are systematically investigated. It is found that spherical-shaped B-BHZA possesses abundant defects and a larger surface area of 64.4 m² g^-1. The factors affecting photocatalytic removal PFOA (e.g., time, pH, initial concentration and dosage) are investigated by modeling the 3D surface response. The removal rate of PFOA is over 90 % in 6 h under UV light at an optimal pH of 2, an initial concentration of 500 μg/L and a dose of dosage 0.5 g/L. The main mechanism occurs by photo-generated h⁺ oxidation and synergistic effects from the photocatalysis process. Though investigating the intermediates of PFOA degradation and F^-, a possibility was proposed that h⁺ initiated the rapidly decarboxylation of PFOA. The unstable perfluoroheptyl group is formatted and further conversed to short chain perfluorocarboxylic acid. This study provides a new insight for the preparation of highly efficient photocatalysts to the treatment of halogenated compounds in UV system.

Methodology for vehicle safety development and assessment accounting for occupant response variability to human and non-human factors

The use of standardized anthropomorphic test devices and test conditions prevent current vehicle development and safety assessments from capturing the breadth of variability inherent in real-world occupant responses. This study introduces a methodology that overcomes these limitations by enabling the assessment of occupant response while accounting for sources of human- and non-human-related variability. Although the methodology is generic in nature, this study explores the methodology in its application to human response in far-side motor vehicle crashes as an example. A total of 405 human body model simulations were conducted in a mid-sized sedan vehicle environment to iteratively train two neural networks to predict occupant head excursion and thoracic injury as a function of occupant anthropometry, impact direction and restraint configuration. The neural networks were utilized in Monte Carlo simulations to calculate the probability of head-to-intruding-door impacts and thoracic AIS 3+ as a function of the restraint configuration. This analysis indicated that the vehicle used in this study would lead to a range of 667 to 2,448 head-to-intruding-door impacts and a range of 3,041 to 3,857 cases of thoracic AIS 3+ in the real world, depending on the seatbelt load limiter. These real-world results were later successfully validated using United States field data. This far-side assessment illustrates how the methodology incorporates the human and non-human variability, generates response surfaces that characterize the effects of the variability, and ultimately permits vehicle design considerations and injury predictions appropriate for real-world field conditions.

Optimization of isolation and transfection conditions of maize endosperm protoplasts

BACKGROUND

Endosperm-trait related genes are associated with grain yield or quality in maize. There are vast numbers of these genes whose functions and regulations are still unknown. The biolistic system, which is often used for transient gene expression, is expensive and involves complex protocol. Besides, it cannot be used for simultaneous analysis of multiple genes. Moreover, the biolistic system has little physiological relevance when compared to cell-specific based system. Plant protoplasts are efficient cell-based systems which allow quick and simultaneous transient analysis of multiple genes. Typically, PEG-calcium mediated transfection of protoplast is simple and cost-effective. Notably, starch granules in cereal endosperm may diminish protoplast yield and integrity, if the isolation and transfection conditions are not accurately measured. Prior to this study, no PEG-calcium mediated endosperm protoplast system has been reported for cereal crop, perhaps, because endosperm cells accumulate starch grains.

RESULTS

Here, we showed the uniqueness of maize endosperm-protoplast system (EPS) in conducting endosperm cell-based experiments. By using response surface designs, we established optimized conditions for the isolation and PEG-calcium mediated transfection of maize endosperm protoplasts. The optimized conditions of 1% cellulase, 0.75% macerozyme and 0.4 M mannitol enzymolysis solution for 6 h showed that more than 80% protoplasts remained viable after re-suspension in 1 ml MMG. The EPS was used to express GFP protein, analyze the subcellular location of ZmBT1, characterize the interaction of O2 and PBF1 by bimolecular fluorescent complementation (BiFC), and simultaneously analyze the regulation of ZmBt1 expression by ZmMYB14.

CONCLUSIONS

The described optimized conditions proved efficient for reasonable yield of viable protoplasts from maize endosperm, and utility of the protoplast in rapid analysis of endosperm-trait related genes. The development of the optimized protoplast isolation and transfection conditions, allow the exploitation of the functional advantages of protoplast system over biolistic system in conducting endosperm-based studies (particularly, in transient analysis of genes and gene regulation networks, associated with the accumulation of endosperm storage products). Such analyses will be invaluable in characterizing endosperm-trait related genes whose functions have not been identified. Thus, the EPS will benefit the research of cereal grain yield and quality improvement.

Efficient optimization of high-dose formulation of novel lyophilizates for dry powder inhalation by the combination of response surface methodology and time-of-flight measurement

Inhalation of proteins/peptides has recently received attention as various biopharmaceuticals have emerged on the market. Novel lyophilisates for dry powder inhalation (LDPIs), which are aerosolized by air impact, have been reported and LDPIs are considered an attractive option for the pulmonary administration of biopharmaceuticals. However, desirable disintegration and aerosolization properties have been unavailable in high-dose formulations, which has been a critical issue. This study aimed to investigate high-dose LDPIs and their optimization. In the present study, lysozyme (Lysoz) was used as a stable model protein and formulated with various amino acids. Furthermore, response surface methodology (RSM) and time-of-flight measurement were applied for efficient optimization. Superior disintegration and aerosolization properties were confirmed in the LDPIs with phenylalanine (Phe) and leucine (Leu). RSM results revealed that 0.5 mg/vial of Phe and 1.0 mg/vial of Leu are the optimal quantities for high-dose formulation. Based on these optimum quantities, high-dose LDPI formulations were prepared and the maximum formulable quantity of Lysoz with acceptable inhalation performance was confirmed to be 3.0 mg/vial. The results suggest that LDPI can cover the milligram-order pulmonary administration of proteins/peptides. LDPIs are expected to have biopharmaceutical applications.

A multivariate statistical strategy to adjust musculoskeletal models

In musculoskeletal modelling, adjusting model parameters is challenging. This paper proposes a multivariate statistical methodology to adjust muscle force-generating parameters optimally. Dynamic residuals are minimized as muscle force-generating parameters are varied (maximal isometric force, optimal fiber length, tendon slack length and pennation angle).First, a sensitivity and a Pareto analyses are carried out in order to sort out and screen the set of parameters having the greatest influence regarding the dynamic residuals. These parameters are then used to create a response surface following a Design of Experiments (DoE) approach. Finally, this surface is used to determine the optimum levels of the design variables (muscle force-generating parameters). The proposed methodology is illustrated by the adjustment of a three-dimensional musculoskeletal model of a sheep forelimb. After adjustment, the reserve actuator values of the elbow and wrist joints were reduced, on average, by 18%, and 16%, respectively. These results demonstrate that the use of multivariate statistical strategies is an effective way to adjust model parameters optimally while reducing dynamic inconsistencies. This study constitutes a step towards a more robust methodology in musculoskeletal modelling, focusing on muscular parameter tuning.

Selective pressurized hot water extraction of nutritious macro-nutrients vs. micro-nutrients in Moringa oleifera leaves-a chemometric approach

Moringa oleifera leaves are widely used in traditional medicine as a food supplement because they are high in essential and nutritious content. Pressurized hot water extraction (PHWE), which is a green approach, was used for the recovery of the macro-nutrient and micro-nutrient elements from dried leaf powder of Moringa oleifera. In this study, response surface methodology was applied to assess the influence of temperature (50-200 °C) and time (5-60 min) on the extractability pattern of macro-nutrient and micro-nutrient elements from the leaves of Moringa oleifera when processed by PHWE. The quantification of macro-nutrient elements such as Ca, K and Mg and micro-nutrient elements like Al, Co, Cr, Cu, Fe, Ni and Zn from the leaves was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Obtained results revealed that the extraction of macro-nutrient elements from the Moringa oleifera leaves was enhanced by increasing the extraction time more than the extraction temperature. On the contrary, the amounts of extractable micro-nutrient elements were increased by increasing the extraction temperature. Hence, the recovery for macro-nutrient elements ranged from 88 to 98% while for micro-nutrients it ranged from 21 to 46%. This implies that macro-nutrient elements are extracted with relatively high selectivity in relation to micro-nutrient elements in Moringa dried leaf powder using the PHWE technique.

Variation in mycorrhizal growth response influences competitive interactions and mechanisms of plant species coexistence

Plant species vary in their growth response to arbuscular mycorrhizal (AM) fungi, with responses ranging from negative to positive. Differences in response to AM fungi may affect competition between plant species, influencing their ability to coexist. We hypothesized that positively responding species, whose growth is stimulated by AM fungi, will experience stronger intraspecific competition and weaker interspecific competition in soil containing AM fungi, while neutrally or negatively responding species should experience weaker intraspecific and stronger interspecific competition. We grew Plantago lanceolata, which responds positively to AM fungi, and Bromus inermis, which responds negatively to AM fungi, in an additive response surface competition experiment that varied the total density and relative frequency of each species. Plants were grown in sterilized background soil that had been inoculated with whole soil biota, which includes AM fungi, or a microbial wash, that contained other soil microbes but no AM fungi, or in sterilized soil that contained no biota. The positively responding P. lanceolata was more strongly limited by intraspecific than interspecific competition when AM fungi were present. By contrast, the presence of AM fungi decreased the strength of intraspecific competition experienced by the negatively responding B. inermis. Because AM fungi are almost always present in soil, strong intraspecific competition in positively responding species would prevent them from outcompeting species that respond neutrally or negatively to AM fungi. The potential for increased intraspecific competition to offset growth benefits of AM fungi could, therefore, be a stabilizing mechanism that promotes coexistence among plant species.

Efficient Optimization of Process Strategies with Model-Assisted Design of Experiments

Conventional design of experiments (DoE) methods require expert knowledge about the investigated factors and their boundary values and mostly lead to multiple rounds of time-consuming and costly experiments. The combination of DoE with mathematical process modeling in model-assisted DoE (mDoE) can be used to increase the mechanistic understanding of the process. Furthermore, it is aimed to optimize the processes with respect to a target (e.g., amount of cells, product titer), which also provides new insights into the process. In this chapter, the workflow of mDoE is explained stepwise including corresponding protocols. Firstly, a mathematical process model is adapted to cultivation data of first experimental data or existing knowledge. Secondly, model-assisted simulations are treated in the same way as experimentally derived data and included as responses in statistical DoEs. The DoEs are then evaluated based on the simulated data, and a constrained-based optimization of the experimental space can be conducted. This loop can be repeated several times and significantly reduces the number of experiments in process development.

The influence of phytase, pre-pellet cracked maize and dietary crude protein level on broiler performance via response surface methodology

Background

The reduction of crude protein levels in diets for broiler chickens may generate economic, environmental and flock welfare and health benefits; however, performance is usually compromised. Whole grain feeding and phytase may improve the utilization of reduced crude protein diets.

Results

The effects of pre-pellet cracked maize (0, 15% and 30%) and phytase (0, 750 and 1500 FTU/kg) in iso-energetic maize-soy diets with three levels of crude protein (22%, 19.5% and 17%) were evaluated via a Box-Behnken response surface design. Each of 13 dietary treatments were offered to 6 replicate cages (6 birds/cage) of male Ross 308 broiler chicks from 7 to 28 d post-hatch. Model prediction and response surface plots were generated from experimental data via polynomial regression in R and only significant coefficients were included and discussed in the predicted models. Weight gain, feed intake and FCR were all influenced by pre-pellet cracked maize, phytase and crude protein level, where crude protein level had the greatest influence. Consequently, the reduction from 22% to 17% dietary crude protein in non-supplemented diets reduced weight gain, feed intake, relative gizzard weight, relative gizzard content and relative pancreas weight but improved FCR. However, the inclusion of 30% cracked maize to 17% crude protein diets restored gizzard weight and 1500 FTU phytase inclusion to 17% crude protein diets increased relative gizzard contents and pancreas weights. Cracked maize and phytase inclusion in tandem to 17% crude protein diets increased weight gain, feed intake and FCR; however, this FCR was still more efficient than broilers offered the non-supplemented 22% crude protein diet. Broilers offered the pre-pellet cracked maize and phytase inclusions reduced AME in 22% crude protein diets but improved AME by 2.92 MJ (14.16 versus 11.24 MJ; P < 0.001) in diets containing 17% crude protein. Ileal N digestibility was greater in broilers offered diets with 17% crude protein than those offered the 22% crude protein diet; irrespective of phytase and pre-pellet cracked maize.

Conclusion

Pre-pellet cracked maize and phytase inclusions will improve the performance of broilers offered reduced crude protein diets.

Effects of ionic interactions on protein stability prediction using solid-state hydrogen deuterium exchange with mass spectrometry (ssHDX-MS)

Deuterium incorporation in solid-state hydrogen deuterium exchange with mass spectrometry (ssHDX-MS) has been correlated with protein aggregation on storage in sugar-based solid matrices. Here, the effects of sucrose, arginine and histidine buffer on the rate of aggregation of a lyophilized monoclonal antibody (mAb) were assessed using design of experiments (DoE) and response surface methodology. Lyophilized formulations were characterized using ssHDX-MS and Fourier transform infrared spectroscopy (ssFTIR) to assess potential correlation with stability in solid state. The samples were subjected to storage stability at 5 °C and stressed stability at 40 °C/75% RH for 6 months, and the aggregation rate was measured using size exclusion chromatography (SEC). Different levels of arginine had no significant effect on deuterium uptake in ssHDX-MS, although stability studies showed that aggregation rate decreased with increasing arginine concentration. Similarly, when histidine buffer was replaced with phosphate buffer at the same pH and molarity, ssHDX-MS showed no differences in deuterium uptake, but storage stability studies showed a significant increase in aggregation rate. The results suggest that proteins can be stabilized in amorphous solids by ionic interactions which ssHDX-MS does not detect, an important indication of the limitations of the method.

Modelling strategies for assessing and increasing the effectiveness of new phenotyping techniques in plant breeding

New types of phenotyping tools generate large amounts of data on many aspects of plant physiology and morphology with high spatial and temporal resolution. These new phenotyping data are potentially useful to improve understanding and prediction of complex traits, like yield, that are characterized by strong environmental context dependencies, i.e., genotype by environment interactions. For an evaluation of the utility of new phenotyping information, we will look at how this information can be incorporated in different classes of genotype-to-phenotype (G2P) models. G2P models predict phenotypic traits as functions of genotypic and environmental inputs. In the last decade, access to high-density single nucleotide polymorphism markers (SNPs) and sequence information has boosted the development of a class of G2P models called genomic prediction models that predict phenotypes from genome wide marker profiles. The challenge now is to build G2P models that incorporate simultaneously extensive genomic information alongside with new phenotypic information. Beyond the modification of existing G2P models, new G2P paradigms are required. We present candidate G2P models for the integration of genomic and new phenotyping information and illustrate their use in examples. Special attention will be given to the modelling of genotype by environment interactions. The G2P models provide a framework for model based phenotyping and the evaluation of the utility of phenotyping information in the context of breeding programs.

Investigation of CoCrMo material loss in a novel bio-tribometer designed to study direct cell reaction to wear and corrosion products

Wear and corrosion in total hip replacement negatively impact implant service-life and patient well-being. The aim of this study was to generate a statistical response surface of material loss using an apparatus, capable of testing the effect of wear and corrosion products in situ on cells, such as macrophages. The test chamber of a ball-on-flat tribometer operating inside a CO₂ incubator was integrated with an electrochemical setup and adapted for cell culture work. A 20-test series, following a 2-level 3-factor design of experiments, was performed with a ceramic head in reciprocating rotational motion against a CoCrMo-alloy disc, under constant load. The lubricant was cell culture medium (RPMI-1640+10vol% bovine serum). Response surfaces were generated, which statistically showed the influence of motion amplitude, load, and potential on the total mass loss and wear scar volume of the metallic discs. Potential had the highest impact on the total mass loss, while motion amplitude and load significantly influenced the wear scar volume. The concentrations of the alloy elements found in the lubricants reflected the bulk-alloy stoichiometry. The total concentration of Co released into the lubricant (2.3-63 ppm by total mass loss, 1.5 to 62 ppm by ICP-MS) corresponded well with the known range to trigger cell response. Tribocorrosion tests in the presence of cells and tissues, such as macrophages, lymphocytes and/or synovium, will be carried out in the future.

Implications of crop model ensemble size and composition for estimates of adaptation effects and agreement of recommendations

Climate change is expected to severely affect cropping systems and food production in many parts of the world unless local adaptation can ameliorate these impacts. Ensembles of crop simulation models can be useful tools for assessing if proposed adaptation options are capable of achieving target yields, whilst also quantifying the share of uncertainty in the simulated crop impact resulting from the crop models themselves. Although some studies have analysed the influence of ensemble size on model outcomes, the effect of ensemble composition has not yet been properly appraised. Moreover, results and derived recommendations typically rely on averaged ensemble simulation results without accounting sufficiently for the spread of model outcomes. Therefore, we developed an Ensemble Outcome Agreement (EOA) index, which analyses the effect of changes in composition and size of a multi-model ensemble (MME) to evaluate the level of agreement between MME outcomes with respect to a given hypothesis (e.g. that adaptation measures result in positive crop responses). We analysed the recommendations of a previous study performed with an ensemble of 17 crop models and testing 54 adaptation options for rainfed winter wheat (Triticum aestivum L.) at Lleida (NE Spain) under perturbed conditions of temperature, precipitation and atmospheric CO2 concentration. Our results confirmed that most adaptations recommended in the previous study have a positive effect. However, we also showed that some options did not remain recommendable in specific conditions if different ensembles were considered. Using EOA, we were able to identify the adaptation options for which there is high confidence in their effectiveness at enhancing yields, even under severe climate perturbations. These include substituting spring wheat for winter wheat combined with earlier sowing dates and standard or longer duration cultivars, or introducing supplementary irrigation, the latter increasing EOA values in all cases. There is low confidence in recovering yields to baseline levels, although this target could be attained for some adaptation options under moderate climate perturbations. Recommendations derived from such robust results may provide crucial information for stakeholders seeking to implement adaptation measures.

Coconut milk beverage fermented by Lactobacillus reuteri: optimization process and stability during refrigerated storage

This study aimed to establish the optimal conditions of temperature (31-43 °C) and coconut pulp concentration in water 1:3-1:9 (w/v) for the growth of Lactobacillus reuteri LR 92 or DSM 17938 in coconut milk beverage, using a central composite face centered design. The optimized conditions were used for analysis of the viability during the fermentation process, pH, production of sugars and organic acids by High Performance Liquid Chromatography (HPLC) and reuterin production. Coconut milk provided adequate substrate for L. reuteri growth without supplementation. The optimal parameters for L. reuteri viability were: concentration 1:3 (w/v) and 37 °C for LR 92 and concentration 1:3 (w/v) and 34 °C for DSM 17938. Chemical analysis showed that the naturally occurring sucrose in the matrix (ca. 4.4 g/L) was used for cell multiplication and the strains differed in the production and content of organic acids. After fermentation until pH 4.5 ± 0.1, the samples were stored at 4 °C for 30 days and the final cell viability in coconut milk was 7.55 ± 0.07 log CFU/mL for L. reuteri LR 92 and 8.57 ± 0.09 log CFU/mL for DSM 17938. It was detected 0.15 ± 0.03 mM and 0.14 ± 0.04 mM of reuterin produced by DSM 17938 and LR 92, respectively. L. reuteri DSM 17938 presented a great decrease of pH and post acidification after storage. The LR 92 strain showed low post acidification. These results showed that coconut milk provides adequate matrix for the development of new fermented functional beverages.

Effect of culture condition on the growth, biochemical composition and EPA production of alkaliphilic Nitzschia plea isolated in the Southeast of China

To overcome the contamination in open pond, microalgal strain selection should focus on species with tolerability to extreme environments. In this study, a native alkaliphilic algae, diatom Nitzschia plea was obtained in Southeast of China, which could tolerate high concentration of NaHCO₃ (0.15 mol/L) and high pH (> 10). The effects of initial pH, light intensity and temperature on cell growth, biochemical composition and fatty acid profile of N. plea were investigated. Results indicated its specific growth rate could reach 1.2 day^-1, lipid content was in the range 14.6-30.2% of dry weight, eicosapntemacnioc acid (EPA, C20:5) accounted for around 15% of total fatty acids. Alkalic condition benefited for both cell growth and EPA synthesis. Appropriately increasing light intensity and temperature could improve cell growth rate and lipid synthesis, although the proportion of EPA in total fatty acids decreased slightly. The optimal culture condition (pH 9.00, temperature 35.0 °C, light intensity 158.6 µmol/m²s) was suggested for maximum yield of EPA based on the response surface model. The overall biomass productivity and EPA productivity were 0.301 g/L/day and 7.43 mg/L/day, respectively. In conclusion, alkalic environment was helpful for the steady operation of open pond cultivation of N. plea with the characteristics of fast growth rate and high EPA content, which exhibited its commercial value.

Combined effects of binary antibiotic mixture on growth, microcystin production, and extracellular release of Microcystis aeruginosa: application of response surface methodology

The interactive effects of binary antibiotic mixtures of spiramycin (SP) and ampicillin (AMP) on Microcystis aeruginosa (MA) in terms of growth as well as microcystin production and extracellular release were investigated through the response surface methodology (RSM). SP with higher 50 and 5% effective concentrations in MA growth was more toxic to MA than AMP. RSM model for toxic unit approach suggested that the combined toxicity of SP and AMP varied from synergism to antagonism with SP/AMP mixture ratio decreasing from reversed equitoxic ratio (5:1) to equitoxic ratio (1:5). Deviations from the prediction of concentration addition (CA) and independent action (IA) model further indicated that combined toxicity of target antibiotics mixed in equivalent ratio (1:1) varied from synergism to antagonism with increasing total dose of SP and AMP. With the increase of SP/AMP mixture ratio, combined effect of mixed antibiotics on MA growth changed from stimulation to inhibition due to the variation of the combined toxicity and the increasing proportion of higher toxic component (SP) in the mixture. The mixture of target antibiotics at their environmentally relevant concentrations with increased total dose and SP/AMP mixture ratio stimulated intracellular microcystin synthesis and facilitated MA cell lysis, thus leading to the increase of microcystin productivity and extracellular release.

Relationships between response surfaces for tablet characteristics of placebo and API-containing tablets manufactured by direct compression method

In this study, we evaluated the correlation between the response surfaces for the tablet characteristics of placebo and active pharmaceutical ingredient (API)-containing tablets. The quantities of lactose, cornstarch, and microcrystalline cellulose were chosen as the formulation factors. Ten tablet formulations were prepared. The tensile strength (TS) and disintegration time (DT) of tablets were measured as tablet characteristics. The response surfaces for TS and DT were estimated using a nonlinear response surface method incorporating multivariate spline interpolation, and were then compared with those of placebo tablets. A correlation was clearly observed for TS and DT of all APIs, although the value of the response surfaces for TS and DT was highly dependent on the type of API used. Based on this knowledge, the response surfaces for TS and DT of API-containing tablets were predicted from only two and four formulations using regression expression and placebo tablet data, respectively. The results from the evaluation of prediction accuracy showed that this method accurately predicted TS and DT, suggesting that it could construct a reliable response surface for TS and DT with a small number of samples. This technique assists in the effective estimation of the relationships between design variables and pharmaceutical responses during pharmaceutical development.

Oxidative stress prediction: A preliminary approach using a response surface based technique

A response surface was built to predict the lipid peroxidation level, generated in an iron-ascorbate in vitro model, of any organ, which is correlated with the oxidative stress injury in biological membranes. Oxidative stress studies are numerous, usually performed on laboratory animals. However, ethical concerns require validated methods to reduce the use of laboratory animals. The response surface described here is a validated method to replace animals. Tissue samples of rabbit liver, kidney, heart, skeletal muscle and brain were oxidized with different concentrations of FeCl₃ (0.1 to 8mM) and ascorbate (0.1mM), during different periods of time (0 to 90min) at 37°C. Experimental data obtained, with lipid content and antioxidant activity of each organ, allowed constructing a multidimensional surface capable of predicting, by interpolation, the lipid peroxidation level of any organ defined by its antioxidant activity and fat content, when exposed to different oxidant conditions. To check the predictive potential of the technique, two more experiments were carried out. First, in vitro oxidation data from lung tissue were collected. Second, the antioxidant capacity of kidney homogenates was modified by adding melatonin. Then, the response surface generated could predict lipid peroxidation levels produced in these new situations. The potential of this technique could be reinforced using collaborative databases to reduce the number of animals in experimental procedures.

Optimization and validation of a rapid liquid chromatography method for determination of the main polyphenolic compounds in table olives and in olive paste

A high performance liquid chromatography method, coupled to diode-array and fluorescence detectors, with a previous solid-liquid extraction, has been developed for the simultaneous detection and quantification of polyphenolic compounds in table olives and in olive paste. The effects of extraction variables have been studied by response surface methodology. The best conditions were extraction with 100% methanol (2mM NaF) during 30min for table olives, and 91% methanol (2mM NaF) during 40min for olive paste. Chromatographic separation of 26 polyphenols from different families was optimized. This method provides high linearity, in all cases higher than 98.65%, and high sensitivity whose detection limits ranged between 0.08 and 1.11μg/mL. The validated method has been applied for the determination of polyphenols in table olive and olive paste samples. The intra-day and inter-day assay repeatability, in the analysis of real samples was less than 7.6 and 11%, respectively.

Designing and fabrication of curcumin loaded PCL/PVA multi-layer nanofibrous electrospun structures as active wound dressing

Active wound dressings play a significant role in burn and chronic wound treatment. In this study, electrospinning process is used to fabricate a novel three-layer active wound dressing based on ε-polycaprolactone (PCL), polyvinylalcohol (PVA), and curcumin (CU) as a biologically active compound. The main purpose for developing such a system is to control wound exudates, which remains a challenge, as well as enjoying the anti-bacterial property. Electrospinning process parameters are optimized by response surface methodology to achieve appropriate nanofibrous electrospun mats, and then, a three-layer dressing has been designed in view of water absorbability, anti-bacterial, and biocompatibility characteristics of the final dressing. The results illustrate that a three-layer dressing based on PCL/curcumin containing PVA as a middle layer with optimized thickness which is placed over the incision, absorbs three times exudates in comparison with pristine dressing. Anti-bacterial tests reveal that the dressing containing 16% curcumin exhibits anti-bacterial activity without sacrificing the acceptable level of cell viability.

Confidence sets for optimal factor levels of a response surface

Construction of confidence sets for the optimal factor levels is an important topic in response surfaces methodology. In Wan et al. (2015), an exact (1-α) confidence set has been provided for a maximum or minimum point (i.e., an optimal factor level) of a univariate polynomial function in a given interval. In this article, the method has been extended to construct an exact (1-α) confidence set for the optimal factor levels of response surfaces. The construction method is readily applied to many parametric and semiparametric regression models involving a quadratic function. A conservative confidence set has been provided as an intermediate step in the construction of the exact confidence set. Two examples are given to illustrate the application of the confidence sets. The comparison between confidence sets indicates that our exact confidence set is better than the only other confidence set available in the statistical literature that guarantees the (1-α) confidence level.