Impact of surface ultraviolet radiation intensity on hospital admissions for ischemic and hemorrhagic stroke: A large-scale database study using distributed lag nonlinear analysis, 2015-2022, in Harbin, China.

OBJECTIVES: Our aim is to evaluate the impact of surface ultraviolet radiation intensity on hospital admissions for stroke and to compare the correlation and differences among different subtypes of strokes. MATERIALS AND METHODS: We collected daily data on surface ultraviolet radiation intensity, temperature, air pollution, and hospital admissions for stroke in Harbin from 2015 to 2022. Using a distributed lag non-linear model, we determined the correlation between daily surface ultraviolet radiation intensity and the stroke admission rate. Relative risks (RR) with 95% confidence intervals (CI) and attributable fractions (AF) with 95% CI were calculated based on stroke subtypes, gender, and age groups. RESULTS: A total of 132,952 hospitalized stroke cases (including hemorrhagic and ischemic strokes) were included in the study. We assessed the non-linear effects of ultraviolet intensity on hospitalized patients with ischemic and hemorrhagic strokes. Compared to the maximum morbidity benchmark ultraviolet intensity (19.2 × 10^5 for ischemic stroke and 20.25 for hemorrhagic stroke), over the 0-10 day lag period, the RR for extreme low radiation (1st percentile) was 0.86 (95% CI: 0.77, 0.96), and the RR for extreme high radiation (99th percentile) was 0.86 (95% CI: 0.77, 0.96). In summary, -4.842% (95% CI: -7.721%, -2.167%) and -1.668% (95% CI: -3.061%, -0.33%) of ischemic strokes were attributed to extreme low radiation intensity with a lag of 0 to 10 days and extreme high radiation intensity with a lag of 0 to 5 days, respectively. The reduction in stroke hospitalization rates due to low or high ultraviolet intensity was more pronounced in females and younger individuals compared to males and older individuals. None of the mentioned ultraviolet intensity intensities and lag days had a statistically significant impact on hemorrhagic stroke. CONCLUSIONS: Our study fundamentally suggests that both lower and higher levels of surface ultraviolet radiation intensity in Harbin, China, contribute to a reduced incidence of ischemic stroke, with this effect lasting approximately 10 days. This finding holds significant potential for public health and clinical relevance.

In-depth discovery and taste presentation mechanism studies on umami peptides derived from fermented sea bass based on peptidomics and machine learning.

Umami peptides originating from fermented sea bass impart a distinctive flavor to food. Nevertheless, large-scale and rapid screening for umami peptides using conventional techniques is challenging because of problems such as prolonged duration and complicated operation. Therefore, we aimed to screen fermented sea bass using peptidomics and machine learning approaches. The taste presentation mechanism of umami peptides was assessed by molecular docking of T1R1/T1R3. Seventy umami peptides identified in fermented sea bass predominantly originated from 28 precursor proteins, including troponin, myosin, motor protein, and creatine kinase. Six umami peptides with the lowest energies formed stable complexes by binding to T1R3. SER170, SER147, GLN389, and HIS145 are critical binding sites for T1R1/T1R3. Four dominant interacting surface forces were identified: aromatic interactions, hydrogen bonding, hydrophilic bonds, and solvent-accessible surfaces. Our study unveils a method to screen umami peptides efficiently, providing a basis for further exploration of their flavor in fermented sea bass.

The relationship of exercise and cancer-related fatigue in patients with advanced liver cancer: a cross-sectional study.

There is increasing interest in understanding exercise as a potential treatment for cancer-related fatigue (CRF); however, rarely research has been conducted on more aggressive cancers with short survival, such as liver cancer. The purpose of this study was to provide educational ideas for insufficient exercise and provide clues for the design of effective and safe exercise intervention programs with high compliance in patients of advanced liver cancer in the future. Participants were recruited from a tertiary cancer hospital using convenience sampling. All participants were asked to complete self-report questionnaires that assessed their medical and demographic variables, exercise habits and CRF during their hospitalization in the interventional department. Spearman's correlation analysis and Nonparametric test was used to explore correlations between exercise subgroups and CRF. The Baron and Kenny's Approach was used to investigate the mediating effect of exercise index between P-EX and CRF. 207 out of 255 participants were enrolled in this study, with an average age of 55.4 years. The CRF score was 33 (28, 36), and 93.2% had insufficient exercise. Exercise frequency (≥ 3 Times/week) (Z = 4.34, p = 0.037) and maintaining exercise trend (Z = 15.85, p = 0.001) had a positive effect on CRF. P-EX had a great impact on exercise index and affecting CRF directly. Participants in the study showed serious fatigue and insufficient exercise. Exercise education can be initiated earlier, particularly those without regular exercise experience. Sustained light exercise, compliant with exercise habits and interests, three times a week may be a practical way to reduce the risk of CRF in advanced liver cancer.

Cooperative combination of non-targeted metabolomics and targeted taste analysis for elucidating the taste metabolite profile and pathways of traditional fermented golden pompano.

Fermentation plays a key role in taste formation in traditional fermented golden pompano and involves a series of complex metabolic reactions. Indeed, the taste profile of fermented golden pompano exhibits remarkable variation during early fermentation. Herein, nutritional fingerprinting (proteins, amino acids, lipids, etc.) was applied to discriminate the various biomolecular changes involved in golden pompano fermentation. Among the differential metabolites, amino acids, small peptides, lipids, and nucleotides were considered taste-related compounds. An increase in the amino acid content was observed during fermentation, while the peptide content decreased. Glutamic acid, alanine, and lysine had the highest taste activity values and were the main contributors to taste formation. Metabolic pathway enrichment analysis revealed that taste formation was primarily associated with alanine, aspartate, and glutamate metabolism. These findings provide a deeper understanding of taste mechanisms and establish a basis for the targeted regulation of taste formation in the fermented fish industry.

Novel iron-chelating peptide from egg yolk: Preparation, characterization, and iron transportation.

In this work, an egg yolk protein hydrolysate (EYPH) with a high iron-chelating ability (87.32%) was prepared. The fractionation using 60% (v/v) ethanol concentration (E3 fraction) led to the efficiently accumulating the iron-chelating peptides in EYPH. The characterization results showed that iron mainly chelated with carboxyl, amino and phosphate groups of peptides. From E3 fraction, six iron-chelating peptides with MW ranging from 1372.36 to 2937.04 Da were identified and a hypothesized molecular model of DDSSSpSpSpSpSpSVLSK-Fe was simulated. In vitro stability determination showed that E3-Fe chelate owned a good heat, alkalinity and digestion tolerance, but a relatively bad acid tolerance. Finally, iron transport analysis showed that iron in the E3-Fe would be absorbed in caco-2 cell membrane more effectively than that of iron salts, indicating that it was possible to apply the E3-Fe complex as iron supplements.

A novel antioxidant protein of non-phycobiliprotein family derived from marine red alga Porphyra haitanensis.

BACKGROUND: Oxidation has been reported as the one of the deterioration reactions of proteins in aquatic products. Searching for new bioactive substances from marine algae has been one of the main areas in food science and additives. RESULTS: In this study, a novel protein from the red alga Porphyra haitanensis was determined after ammonium sulfate precipitation and gel filtration chromatography. It closely corresponded to the antioxidant activity and was identified as an uncharacterized protein with a molecular mass of 43 kDa, designated Ph43. Bioinformatic analysis revealed that Ph43 is a novel protein of non-phycobiliprotein family with putative chordin domains and rich in α-helical conformation. Recombinant protein (rPh43) was expressed in Escherichia coli as a Hig-tagged protein using a pET-22b vector system and purified by affinity high-performance liquid chromatography. Spectroscopy analysis revealed that there were no structural differences between rPh43 and natural recovered Ph43. Moreover, rPh43 showed equal/higher antioxidant activity compared with Ph43. rPh43 has the potential for application as a natural antioxidant for food stabilization. CONCLUSION: Our results identified a novel antioxidant protein with molecular mass of 43 kDa derived from Porphyra haitanensis that belongs to the non-phycobiliprotein family. © 2023 Society of Chemical Industry.

Alkenyl Thioetherification Enabled by Nickel Catalysis.

This paper describes an efficient strategy to promote alkenyl thioetherifications via the Ni-catalyzed cross-coupling of inactivated or ß-aryl-substituted (E)-alkenyl halides with thio-alcohols/phenols. The present strategy with easy-to-operate reaction conditions represents one of the most effective alkenyl C(sp2)-S bond-forming methods via readily accessible nickel catalysis. Notably, the mildly basic conditions employed facilitate access to a broad scope including protected amino acids, saccharides, and heterocycles. Moreover, this work presents its attractive usefulness by the application in late-stage modifications of several structurally complex natural products and pharmaceuticals.

Copper chelating peptides derived from tilapia (Oreochromis niloticus) skin as tyrosinase inhibitor: Biological evaluation, in silico investigation and in vivo effects.

Binuclear copper ions at the active site determine the catalysis of tyrosinase (TYR)1 whose activity can be inhibited by copper's chelation with other compounds. In this study, tilapia (Oreochromis niloticus) skin was used to generate TYR-inhibitory peptides after being treated by different enzymes and 4 h-Alcaline protease hydrolysate exhibited the highest TYR inhibition and copper chelation. Immobilized metal affinity chromatography was used for purifying copper chelating peptides, among which PFRMY (IC50: 0.43 ± 0.08 mg/mL) and RGFTGM (IC50: 1.61 ± 0.04 mg/mL) exhibited the highest TYR-inhibitory capacity and the lowest docking energy. Both two peptides inhibited TYR in a mixed manner and interacted with key residues binding to copper ions within TYR mainly by hydrogen bonds and hydrophobic forces, while PFRMY had a more compact and stable conjugation with TYR. Zebrafish assay revealed that PFRMY reduced not only melanin synthesis but in vivo TYR activity.

Antioxidant Activity of Gracilaria lemaneiformis Polysaccharide Degradation Based on Nrf-2/Keap-1 Signaling Pathway in HepG2 Cells with Oxidative Stress Induced by H2O2.

The objective of this research was to investigate the antioxidant activity of Gracilarialemaneiformis polysaccharide degradation and its underlying mechanism involved in the Nrf-2/Keap-1 signaling pathway in HepG2 cells with oxidative stress induced by H2O2. The result of the scavenging ability of free radicals showed that GLP-HV (polysaccharide degraded by H2O2-vitamin C (Vc)) performed a better scavenging ability than GLP (G.lemaneiformis polysaccharide). Moreover, the scavenging ability of polysaccharide to these free radicals from strong to weak was as follows: superoxide radical, ferric ion, ABTS+, and DPPH radical, and their IC50 values were 3.56 ± 0.0028, 4.97 ± 0.18, 9.62 ± 0.35, and 23.85 ± 1.78 mg/mL, respectively. Furthermore, GLP-HV obviously relieved oxidative stress in HepG2 cells, which strengthened the activity of T-AOC, CAT, GSH-PX, and SOD, and diminished the intensity of MDA, intracellular ROS, and calcium ion based on the Nrf-2/Keap-1 signaling pathway. The PCR result revealed that polysaccharide upregulated the expression of the genes Nrf-2, HO-1, NQO-1, and ZO-1 and downregulated Keap-1. The correlation between chemical properties and antioxidant mechanism of GLP-HV was evaluated via a heat map. The results illustrated that reducing sugar and active groups presented a positive correlation, and molecular weight and viscosity exhibited a negative relation with antioxidant activity.

Nickel-catalyzed cross-electrophile allylation of vinyl bromides and the modification of anti-tumour natural medicine ß-elemene.

Herein, we present a facile and efficient allylation method via Ni-catalyzed cross-electrophile coupling of readily available allylic acetates with a variety of substituted alkenyl bromides using zinc as the terminal reductant. This Ni-catalyzed modular approach displays excellent functional group tolerance and a broad substrate scope, which the creation of a series of 1,4-dienes including several structurally complex natural products and pharmaceutical motifs. Moreover, the coupling strategy has the potential to realize enantiomeric control. The practicality of this transformation is demonstrated through the potent modification of the naturally antitumor active molecule ß-elemene.

Taste mechanism of umami peptides from Chinese traditional fermented fish (Chouguiyu) based on molecular docking using umami receptor T1R1/T1R3.

Umami peptides formed during fermentation of Chouguiyu contribute to its unique taste. In this study, the umami taste of peptide extract from Chouguiyu was improved after fermentation, as determined by sensory evaluation. After umami peptide identification using peptidomics, molecular docking with T1R1/T1R3 was used to evaluate the likely taste mechanism. There were 400 umami peptides identified in Chouguiyu, most of which were significantly enhanced after fermentation. These peptides were hydrolyzed from 77 precursor proteins, mainly including myosin, troponin, and titin, at multiple locations. The umami structures in the six core umami peptides with the lowest binding energy were easy to connect with Ser, Glu, His, Gln, Arg and Lys residues in T1R3 through hydrogen bond and salt bridge. The hydrogen bond, hydrophilcity, aromatic interaction, and solvent accessible surface were the main interaction surface forces. This study provides important information of the unique taste formation in Chouguiyu based on umami peptides.

Enzymatically synthesized γ-[Glu](n≥1)-Gln as novel calcium-binding peptides to deliver calcium with enhanced bioavailability.

Novel γ-[Glu](n≥1)-Gln-Ca chelates were prepared by using γ-[Glu](n≥1)-Gln (mixture peptides containg γ-Glu-Gln, γ-Glu-Glu-Gln, γ-Glu-Glu-Glu-Gln, γ-Glu-Glu-Glu-Glu-Gln, γ-Glu-Glu-Glu-Glu-Glu-Gln) which were synthesized by glutaminase. Based on single factor and orthogonal array experiments, the optimal calcium-chelation conditions were as follows: 30 min chelation at 70 °C; peptide concentration, 0.15 g/mL; mixture peptides-to-calcium mass ratio, 25:1. The particle size of chelates was 743.6 ± 64.2 nm and the chelates appeared stable neutral molecular entities with 91.33% of chelation rate and 35.2 mg/g of calcium, also with higher thermostability. Chelated calcium ions might be surrounded by coordination bonds linking to two or more connecting points: oxygen atoms (carboxyl oxygen, hydroxyl oxygen and oxygen of peptide bonds) and nitrogen atoms (amino nitrogen). The chelates could be used for food/nutraceutical applications, as no toxicity at 0.125-10 mg/mL and enhanced efficiency in calcium release (releasing percentage over 85% at pH 8.0), transport and uptake compared with CaCl2 were detected in Caco-2 cells.

Next-generation sequencing identification and multiplex RT-PCR detection for viruses infecting cigar and flue-cured tobacco.

BACKGROUND: Early, precise and simultaneous identification of plant viruses is of great significance for preventing virus spread and reducing losses in agricultural yields. METHODS AND RESULTS: In this study, the identification of plant viruses from symptomatic samples collected from a cigar tobacco planting area in Deyang and a flue-cured tobacco planting area in Luzhou city, Sichuan Province, China, was conducted by deep sequencing of small RNAs (sRNAs) through an Illumina sequencing platform, and plant virus-specific contigs were generated based on virus-derived siRNA sequences. Additionally, sequence alignment and phylogenetic analysis were performed to determine the species or strains of these viruses. A total of 27930450, 21537662 and 28194021 clean reads were generated from three pooled samples, with a total of 105 contigs mapped to the closest plant viruses with lengths ranging from 34 ~ 1720 nt. The results indicated that the major viruses were potato virus Y, Chilli veinal mottle virus, tobacco vein banding mosaic virus, tobacco mosaic virus and cucumber mosaic virus. Subsequently, a fast and sensitive multiplex reverse transcription polymerase chain reaction assay was developed for the simultaneous detection of the most frequent RNA viruses infecting cigar and flue-cured tobacco in Sichuan. CONCLUSIONS: These results provide a theoretical basis and convenient methods for the rapid detection and control of viruses in cigar- and flue-cured tobacco.

Improving the color and functional properties of seabuckthorn seed protein with phytase treatment combined with alkaline solubilization and isoelectric precipitation.

BACKGROUND: Reducing anti-nutritional factors like phytates in seed protein products requires an ongoing effort. This study was the first to investigate the phytic acid content in seabuckthorn seed protein (SSP) and its reduction by an exogenous phytase during protein isolation from seabuckthorn seed meal through the common alkaline solubilization-isoelectric precipitation process. RESULTS: The additional phytase treatment could reduce the content of phytic acid from 22.46 to 13.27 g kg-1 , leading to SSP products with lighter color (lower ΔE* ), higher protein solubility, higher in vitro digestibility, but lower phenolic antioxidant content (including flavonoids and procyanidins) and some beneficial ions like Ca, Fe, Mg, and Zn. The Fourier transform infrared (FTIR) results indicated that the secondary structure of protein changed under the treatment with phytase. Correlation analysis showed that L* was significantly negatively correlated with TP, TPC and TF (P < 0.001), while a* and b* were significantly positively correlated with them (P < 0.001). CONCLUSIONS: There may be a trade-off between protein functionalities and other health-promoting components when a phytase treatment is included in SSP isolation. © 2021 Society of Chemical Industry.

Branched-Chain Amino Acids Catabolism Pathway Regulation Plays a Critical Role in the Improvement of Leukopenia Induced by Cyclophosphamide in 4T1 Tumor-Bearing Mice Treated With Lvjiaobuxue Granule.

Background: Cyclophosphamide is a common tumor chemotherapy drug used to treat various cancers. However, the resulting immunosuppression leads to leukopenia, which is a serious limiting factor in clinical application. Therefore, the introduction of immunomodulators as adjuvant therapy may help to reduce the hematological side effects of cyclophosphamide. Lvjiaobuxue granule has been widely used in the clinical treatment of gynecological diseases such as anemia and irregular menstruation. Recently, it has been found to increase the function of white blood cells, but its mechanism of action is still unclear. We aimed to reveal the mechanisms of Lvjiaobuxue granule against acute leukopenia by an integrated strategy combining metabolomics with network pharmacology. Methods: Subcutaneously inoculated 4T1 breast cancer cells to prepare tumor-bearing mice, intraperitoneal injection of cyclophosphamide to establish a 4T1 tumor-bearing mice leukopenia animal model, using pharmacodynamic indicators, metabolomics, network pharmacology and molecular biology and other technical methods. To comprehensively and systematically elucidate the effect and mechanism of Lvjiaobuxue granule in improving cyclophosphamide-induced leukopenia in 4T1 tumor-bearing mice. Results: Lvjiaobuxue granule can improve the blood routine parameters and organ index levels of the leukopenia model of 4T1 tumor-bearing mice. Metabolomics studies revealed that 15 endogenous metabolites in the spleen of mice were considered as potential biomarkers of Lvjiaobuxue granule for their protective effect. Metabonomics and network pharmacology integrated analysis indicated that Lvjiaobuxue granule exerted the leukocyte elevation activity by inhibiting the branched-chain amino acids (BCAAs) degradation pathway and increasing the levels of valine, leucine and isoleucine. The results of molecular biology also showed that Lvjiaobuxue granule can significantly regulate the key enzymes in the catabolism of BCAAs, which further illustrates the importance of BCAAs in improving leukopenia. Conclusion: Lvjiaobuxue granule exerts obvious pharmacological effects on the leukopenia model of 4T1 tumor-bearing mice induced by cyclophosphamide, which could be mediated by regulating the branched-chain amino acid degradation pathway and the levels of valine, leucine and isoleucine.

Iron-Catalyzed α,ß-Dehydrogenation of Carbonyl Compounds.

An iron-catalyzed α,ß-dehydrogenation of carbonyl compounds was developed. A broad spectrum of carbonyls or analogues, such as aldehyde, ketone, lactone, lactam, amine, and alcohol, could be converted to their α,ß-unsaturated counterparts in a simple one-step reaction with high yields.

Essential Oil of Acorus tatarinowii Schott Ameliorates Aß-Induced Toxicity in Caenorhabditis elegans through an Autophagy Pathway.

BACKGROUND: Acorus tatarinowii Schott [Shi Chang Pu in Chinese (SCP)] is a traditional Chinese medicine frequently used in the clinical treatment of dementia, amnesia, epilepsy, and other mental disorders. Previous studies have shown the potential efficacy of SCP against Alzheimer's disease (AD). Nevertheless, the active constituents and the modes of action of SCP in AD treatment have not been fully elucidated. PURPOSE: The aim of this study was to investigate the protective effects of SCP on abnormal proteins and clarify its molecular mechanisms in the treatment of AD by using a Caenorhabditis elegans (C. elegans) model. METHODS: This study experimentally assessed the effect of SCP-Oil in CL4176 strains expressing human Aß in muscle cells and CL2355 strains expressing human Aß in pan-neurons. Western blotting, qRT-PCR, and fluorescence detection were performed to determine the oxidative stress and signaling pathways affected by SCP-Oil in nematodes. RESULTS: SCP-Oil could significantly reduce the deposition of misfolded Aß and polyQ proteins and improved serotonin sensitivity and olfactory learning skill in worms. The analysis of pharmacological action mechanism of SCP-Oil showed that its maintaining protein homeostasis is dependent on the autophagy pathway regulated partly by hsf-1 and sir-2.1 genes. CONCLUSION: Our results provide new insights to develop treatment strategy for AD by targeting autophagy, and SCP-Oil could be an alternative drug for anti-AD.

Experimental study on diesel engine exhaust gas recirculation performance and optimum exhaust gas recirculation rate determination method.

In order to study the exhaust gas recirculation (EGR) performance of marine diesel engines, a venturi high-pressure EGR device was established to overcome the exhaust gas reflow problem based on a certain type of turbocharged diesel engine. The EGR performance test is accomplished and an optimal EGR decision-making optimization method based on grey correlation coefficient modified is proposed. The results show that the venturi tube EGR can basically meet the injection requirements of high-pressure exhaust gas and achieve good results. Through the venturi tube EGR, the NO X emissions reduce significantly with the maximum drop of 30.6%. The explosive pressure in cylinder reduces with the EGR rate increases and the cylinder pressure curve shows a single peak at low-speed conditions and double peaks at high-speed condition. However, the fuel consumption rate, NO X and smoke have been negatively affected. Due to small samples, the traditional evaluation method is difficult to determine the optimal EGR rate reasonably, while the proposed method can effectively solve this problem. It can weaken the shortcomings of subjective judgement and greatly improve the rationality of decision-making results.

Metabolomics studies on corticosterone-induced PC12 cells: A strategy for evaluating an in vitro depression model and revealing the metabolic regulation mechanism.

There are three types of differentiated (un-, poorly- and well-differentiated) PC12 cells, which have been widely used as a model system for depression studies after the administration of corticosterone (CORT). In order to investigate the underlying metabolic profiles of CORT-induced PC12 cells and evaluate the suitable differentiated types of PC12 cells for use in depressive studies, proton nuclear magnetic resonance (1H NMR) metabolomics coupled with network analysis approaches were employed. The results showed that CORT induced metabolic alterations in PC12 cells. There were 8 and 13 common differential metabolites in intracellular and extracellular extracts, respectively, of the three types of differentiated PC12 cells in response to CORT treatment, and the perturbed metabolic pathways were involved in amino acid metabolism, glutathione metabolism, pyruvate metabolism and inositol phosphate metabolism. Eighteen protein targets of depression were identified from the five different metabolic pathways from metabolomics and network analysis among the three types of CORT-induced differentiated PC12 cells, and these proteins were all found in the pathways that were perturbed by CORT treatment of poorly-differentiated PC12 cells. These results may indicate that the metabolism of CORT-induced PC12 cells is similar to the pathogenesis of depression, and poorly-differentiated PC12 cells are the most suitable cells for depressive research among the distinct types of differentiated PC12 cells. Thus, an effective predicative strategy to evaluate the in vitro disease models could be referenced.

Optimized modelling and application of exhaust gas recirculation performance evaluation of turbocharged diesel engine.

Aimed at the problem of exhaust gas recirculation (EGR) performance evaluation and optimal EGR rate determination of turbocharged diesel engines, an optimized decision-making method, based on grey theory and entropy weight, was proposed. The internal combustion pressure, fuel consumption rate, NOX, CO and smoke were selected as the decision-making targets and the initial decision-making model was established based on the traditional grey decision-making theory. According to the characteristics and optimization requirements of EGR, the optimal compromise between combustion and emission performance is proposed to transform into decision-making target weighting problem, then an optimized subjective weighting method based on expert scoring and grey relational analysis is proposed. Finally, the entropy weight method was used to solve the objective weight and the optimized multi-objective grey decision-making model was established, which can not only weaken the human error of subjective empowerment, but also fully explore the intrinsic relationship of the evaluation indexes. At last, an optimization simulation platform for EGR performance evaluation based on MATLB/GUIDE was designed and established. The results show that the optimization simulation platform can effectively improve the efficiency of simulation calculation, which is more convenient for practical engineering applications. The optimized method can successfully realize EGR performance evaluation and optimal EGR rate determination under different working conditions. The decision-making result was consistent with the present EGR control strategies, which provide a new research idea for EGR performance optimization.