The Enrichment of Docosahexaenoic Acid from Microalgal Oil by Urea Complexation via Rotary-evaporation Crystallization.

Urea complexation is a widely used method for enriching polyunsaturated fatty acids, and cooling is the traditional approach for urea crystallization. This study aimed to investigate the potential of rotary-evaporation under vacuum as an alternative method for urea crystallization in urea complexation to enrich docosahexaenoic acid (DHA). DHA-containing microalgal oil was converted to ethyl esters (EE) as the raw material. In comparison to cooling, rotary-evaporation crystallization, as a post-treatment method for urea complexation, led to higher DHA contents in the non-urea included fractions. The ratios of urea to EE converted from DHA-containing microalgal oil was found to be the primary factors influencing urea complexation when using rotary-evaporation crystallization. Through an orthogonal test, optimal process conditions were determined, including a urea/EE ratio of 2, an ethanol/urea ratio of 7, and a rotary-evaporation temperature of 75℃. Under these conditions, a concentrate containing more than 90% DHA could be obtained.

Low Fatization of High-Fat Surimi-Based Products: Optimization of the Application of Protein Matrix Fat Substitution Methods.

The low fatization of high-fat foods is a significant trend that will impact the future developments of food products. Consumers have regarded health attributes as a critical indicator for purchasing food. In this study, enzyme-modified soy protein isolate, sea fish collagen, and ovalbumin were used to prepare the composite fat substitute for the protein matrix. This matrix was applied to the traditional surimi-based product Nemipterus virgatus fish sausage to replace the exogenous fat, and a new type of low-fat fish sausage was developed. This change is expected to reduce the exogenous fat in the traditional fish sausage without reducing the flavor and sensory quality of the original product. The results showed that taking the sensory evaluation and gel strength value of the product as indicators, the optimal ratio of compound fat substitute (enzyme-modified soy protein isolate:sea fish collagen:ovalbumin) was 2:1:3 when using the orthogonal test method for the first time. In the next step, with compound fat substitutes, exogenous fats and transglutaminase as the main factors, single factor and response surface method were used to explore the best formula of new low-fat Nemipterus virgatus fish sausage. The results showed that the best gel strength and sensory evaluation scores were obtained when the compound fat substitute, TGase, and exogenous fat were 0.59 g, 0.245 g, and 8.03 g, respectively. The optimal formulation of the low-fat Nemipterus virgatus fish sausage was obtained as follows: surimi, 67.52%; complex fat substitute, 0.66%; TGase, 0.28%; fat, 9.04%; starch, 6.75%; sugar, 3.94%; salt, 2.25%; monosodium glutamate, 0.23%; I&G, 0.34%; and water, 9%. Compared with the traditional fish sausage, the content of exogenous fat in the new, low-fat Nemipterus virgatus fish sausage was reduced by 54.8%. Meanwhile, the sensory score of fish sausage was increased by 21.79%, maintaining its good flavor and sensory quality. This study provides an important reference value for developing new low-fat surimi-based products.

Study on prevention and control measures of sandstone geothermal reinjection plugging.

In the process of geothermal tailwater reinjection of sandstone, the problem of plugging has been seriously restricting the continuous development of geothermal reinjection for many years, and the problems of plugging are complex and changeable. The plugging in the process of reinjection can be divided into physical plugging, chemical plugging, microbial plugging and gas plugging. Given these four types of blocking, according to the mechanism characteristics of the blocking caused by them, this paper puts forward corresponding blocking prevention measures and solves the current blocking problems by filtering, adding a scale inhibitor, intermittent reinjection, adding chlorine dioxide and regular lifting. In addition, the existing reinjection process and the equipment flow are relatively simple and cannot achieve the goal of efficient reinjection. Therefore, a complete set of reinjection processes is designed to ensure the efficient reinjection of sandstone geothermal tailwater.

Tribological Performance of Diamond Films with Different Roughnesses of Silicon Nitride Substrates and Carbon Source Concentrations.

Diamond films were deposited on silicon nitride (Si3N4) substrates with three different roughnesses using the method of hot-filament chemical vapor deposition (HFCVD). The tribological properties of the film were studied by changing the deposition time, deposition distance, and methane (CH4) concentration. The friction coefficient, delamination threshold load, and wear rate of the diamond films were tested and calculated using the reciprocating friction and wear test under dry friction conditions. The results show that, when the deposition time is 12 h, the bonding force of the film is the lowest and the friction coefficient is the largest (0.175, 0.438, and 0.342); the deposition distance has little effect on the friction performance. The friction coefficients (0.064, 0.107, and 0.093) of nano-diamond films (NCD) prepared at a 40 sccm CH4 concentration are smaller than those of micro-diamond films (MCD) prepared at a 16 sccm CH4 concentration. The load thresholds before delamination of Ra 0.4 µm substrate diamond film are as high as 40 N and 80 N, whereas the diamond films deposited on Ra 0.03 µm substrates have lower wear rates (4.68 × 10-4 mm3/mN, 5.34 × 10-4 mm3/mN) and low friction coefficients (0.119, 0.074, 0.175, and 0.064). Within a certain load range, the deposition of a diamond film on a Ra 0.03 µm Si3N4 substrate significantly reduces the friction coefficient and improves wear resistance. Diamond film can improve the friction performance of a workpiece and prolong its service life.

Detection and correlation analysis of shellfish pathogens in Dadeng Island, Xiamen.

Food poisoning is caused by pathogenic bacteria in water and aquatic products, especially bivalves (e.g., oysters, clams), which can bioaccumulate pathogenic bacteria. Polluted water and aquatic products thus pose a serious threat to human health and safety. In this study, the types of pathogenic bacteria in water samples and shellfish collected from the Dadeng offshore area in Xiamen were examined. We also analyzed the relationships between dominant pathogens and major climate and water quality parameters. Our objective was to provide reference data that may be used to help prevent bacterial infections and to improve aquatic food hygiene in Xiamen and its surrounding areas to safe levels, thus ensuring the health of Xiamen residents. We found that the main pathogenic bacteria were Vibrio and Bacillus, with the dominant pathogen being Vibrio parahaemolyticus. Physical and chemical indexes (water temperature, salinity, pH, dissolved oxygen, and turbidity) of water bodies and the 3-day accumulated rainfall were found to be important factors affecting the occurrence and abundance of V. parahaemolyticus.

Plasma titanium level is positively associated with metabolic syndrome: A survey in China's heavy metal polluted regions.

OBJECTIVE: Several heavy metals have been reported to be associated with metabolic syndrome(MetS) in general population, while effects of multiple metals exposure on MetS in residents living in heavy metal polluted regions have not been investigated. We aimed to assess the association of 23 metal levels and MetS among population living in China's heavy metal polluted regions. METHODS: From August 2016 to July 2017, a total of 2109 eligible participants were consecutively enrolled in our study in Hunan province, China. The levels of plasma and urine metals were measured by inductively coupled plasma mass spectrometer (ICP-MS). MetS was defined by the criteria of the International Diabetes Federation. Multivariable regression models were applied to analysis the potential relationship. RESULTS: In the overall population, crude model showed positive relationship of plasma titanium (Ti) with MetS and negative association of urine vanadium, iron, and selenium with MetS. After adjusted for potential confounders, only plasma Ti was positive associated with MetS (adjusted OR for Q4 versus Q1: 1.46; 95% CI: 1.06-1.99), and this positive correlation was explained by abdominal obesity (OR = 1.84, 95% CI: 1.41-2.39) and high triglycerides (OR = 2.23, 95% CI: 1.68-2.96). Further linear regression analysis revealed significant association of plasma Ti levels with waist circumference (ß = 0.0056, 95% CI: 0.0004-0.0109, P = 0.036) and triglycerides (ß = 0.0012, 95% CI: 0.0006-0.0019, P < 0.001), respectively. CONCLUSION: High plasma Ti level was associated with increased risk of MetS via increasing waist circumference and triglycerides in people under high metal exposure.

Distinct uric acid trajectories are associated with incident diabetes in an overweight Chinese population.

AIM: To explore uric acid (UA) trajectories in different body mass index (BMI) populations and to determine their associations with incident diabetes. METHODS: A total of 4566 adults without diabetes in 2011 were enrolled. All participants underwent a medical examination every year until 2016, and were classified into three subgroups based on BMI: non-obese (BMI<24kg/m2); overweight (BMI ≥24kg/m2 but<28kg/m2); and obese (BMI ≥28kg/m2). Distinct UA trajectories were identified through group-based trajectory modelling (GBTM). Cox proportional-hazards models were applied to evaluate the associations between UA trajectories and risk of incident diabetes. RESULTS: UA trajectories were identified in the three BMI subgroups: 'low' (42.4% in non-obese, 22.1% in overweight, 22.0% in obese); 'moderate' (32.5%, 41.1%, 34.8%); 'moderate-high' (18.6%, 29.5%, 30.8%); and 'high' (6.5%, 7.3%, 12.4%). After a 5-year follow-up, 170 (3.7%) participants had developed diabetes. The prevalence of new-onset diabetes increased progressively with the higher UA trajectories in the BMI groups (P values<0.05). Whereas compared with the low trajectory, a significant association between a high UA trajectory and incidence of diabetes was observed only in the overweight population [hazard ratio (HR): 6.95, 95% confidence interval (CI): 1.90-25.45], with no significant associations found in either the non-obese (HR: 0.67, 95% CI: 0.13-3.52) or obese (HR: 0.40, 95% CI: 0.06-2.64) populations, in the fully adjusted model. CONCLUSION: Higher UA trajectories are significantly associated with an increased risk of incident diabetes, thereby suggesting that monitoring UA trajectories over time may assist in the identification of prediabetes and diabetes, particularly in the overweight population.

Gender-specific associations between apolipoprotein A1 and arterial stiffness in patients with nonalcoholic fatty liver disease.

BACKGROUND: Lipid metabolism factors may play an important role in the progression of nonalcoholic fatty liver disease (NAFLD) and its related cardiovascular dysfunctions. The study aims to assess whether Apolipoprotein A-1 (ApoA1) was associated with vascular stiffness in NAFLD patients. METHODS: From 2012 to 2013, we included 2,295 non-alcohol users with fatty liver disease (1,306 male patients) and completely excluded subjects who drank any alcohol ever to eliminate the effect of alcohol intake. The serum ApoA1 levels and the brachial-ankle pulse wave velocity (baPWV) were measured. RESULTS: The baPWV in men was much higher than in female patients (1,412.79 cm/s vs. 1,358.69 cm/s, P < 0.001). ApoA1 level was positively associated with baPWV odd ratio (OR), 4.18; 95% confidence interval (CI) [1.16-15.1], P < 0.05) in patients with AST/ALT < 1 and (OR, 4.70; 95% CI [1.36-16.23], P < 0.05) in patients with AST/ALT ≥ 1 respectively. Only arterial stiffness in men was associated with ApoA1 (OR, 3.96; 95% CI [1.29-12.30], P < 0.05) in logistics regression models adjusted for age, gender, body mass index, education attainment, physical activity, smoking, history of hypertension and high-density lipoprotein. The relationship between ApoA1 and baPWV in male NAFLD patients remained significant (confidence, 156.42; 95% CI [49.34-263.50], P < 0.05) in the fully adjusted linear regression model. CONCLUSION: The serum ApoA1 was associated with arterial stiffness in male NAFLD patients. Increased ApoA1 level should be considered as an independent risk factor for arterial stiffness in male NAFLD patients, suggesting that NAFLD may alter arterial stiffness by "ApoA1-related" mechanism in men.

Elevated triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio increased risk of hyperuricemia: a 4-year cohort study in China.

PURPOSE: Previous studies revealed that high serum uric acid (SUA) levels correlated with increased triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio. However, evidence is lacking regarding whether TG/HDL-C is an independent risk factor or just a simple marker of hyperuricemia. We aimed to investigate the relationship between TG/HDL-C and the risk of hyperuricemia in Chinese population. METHODS: This retrospective cohort study involved 15,198 subjects (43.14 ± 13.13 years, 54.9% men) who were free of hyperuricemia at baseline. The association between TG/HDL-C and the risk of hyperuricemia, in the total sample and stratified by subgroups, was examined by multiple logistic regression analyses. RESULTS: During 4 years follow-up, hyperuricemia occurred in 2365 (15.6%) participants. The cumulative incidence of hyperuricemia was significantly elevated with increasing TG/HDL-C quartiles (5.9, 10.8, 18.4, and 27.5%, respectively). After multivariate adjustment, the odds ratio for hyperuricemia in the highest compared with the lowest quartile of TG/HDL-C was 1.80 (95% confidence interval [CI] 1.49, 2.18), and each SD increment of TG/HDL-C ratio caused a 10% additional risk for hyperuricemia. Moreover, subgroup analyses showed that the association between TG/HDL-C and the risk of hyperuricemia was more pronounced in women and normal-weight adults. The results were consistent when analyses were restricted to participants without metabolic syndrome. CONCLUSIONS: TG/HDL-C ratio was positively related to the risk of hyperuricemia in Chinese population, particularly in women and normal-weight individuals. These findings suggested the potential of TG/HDL-C ratio to serve as an independent risk indicator in the prevention of hyperuricemia.

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The incidence of non-alcohol fatty liver disease (NAFLD) is increasing year by year, and the relevant cardiovascular events have become a major problem in chronic diseases management. The activation of innate immunity is closely related to the development of NAFLD. The immune cells include Kupffer cells, neutrophils, dendritic cells, and natural killer T cells, which acts through the activation of innate immunity-related signals mediated by pattern recognition receptors.

Association of lipid accumulation product trajectories with 5-year incidence of type 2 diabetes in Chinese adults: a cohort study.

BACKGROUND: Lipid accumulation product (LAP) is an index describing the overaccumulation of lipid. Baseline LAP was used for type 2 diabetes (T2D) prediction in previous studies. But the longitudinal trajectories of LAP, which reflect the efficacy of patients' lipid-lowering treatment and lifestyle improvement, have rarely been studied. The aim of this study is to explore the association of lipid accumulation product trajectories with 5-year incidence of type 2 diabetes. METHODS: This cohort study included 4508 non-diabetic participants with a median age of 42 years. Using the group-based trajectory modeling (GBTM), LAP from 2011 to 2016 were determined and identified as three trajectories: low (n = 3639), moderate (n = 800), and high (n = 69). Baseline LAP was divided into groups by percentiles and tertiles respectively for the comparison of LAP trajectories. The associations between 5-year T2D incidence and LAP trajectories and baseline LAP were both assessed by generalized linear models. RESULTS: From 2011 to 2016, 169 participants developed T2D (the 5-year incidence of 3.8%). For participants with low, moderate, and high trajectories, the incidence of T2D was 2.1, 10.0, and 15.9%, respectively. A significant trend was observed in the relative risks (RRs) of 5-year incident T2D in participants with moderate (RR, 1.95; 95% CI: 1.41-2.70) and high LAP trajectory (RR, 2.20; 95% CI: 1.12-4.30) in the fully adjusted model (p for trend< 0.001). However, there were no statically significant trends in RRs in different tertiles of baseline LAP found after full adjustments. CONCLUSION: The trajectories of LAP has an independent effect on 5-year T2D incidence beyond LAP measured at baseline.

Determination of fucoxanthinol in rat plasma by liquid chromatography-tandem mass spectrometry.

Previous studies have indicated that dietary fucoxanthin is mainly converted into fucoxanthinol (the deacetylated form) in mammals, but the pharmacokinetics of fucoxanthinol remains unknown. In this study, after intravenous (i.v.) and intragastric gavage (i.g.) administration of fucoxanthinol to rats at 0.8 and 20 mg/kg respectively, one-step protein precipitation with methanol was employed to prepared plasma samples, and an accurate and precise liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method was developed to determine fucoxanthinol. Plasma samples were resolved by LC-MS/MS on a reverse-phase SB-C18 column equilibrated and eluted with acetonitrile (A, 0.1% formic acid) and water (B, 0.1% formic acid) (A:B = 92:8, v/v) at a flow rate of 0.5 mL/min and the injection volume was 5 µL. Analytes were monitored by Selected-reaction monitoring in positive electrospray ionization mode. The calibration curves for fucoxanthinol were linear over the range 1.17-300 ng/mL. The inter-day and intra-day accuracy and precision were within 1.55%-7.90%. The method was applied successfully in a pharmacokinetic study of fucoxanthinol and the resulting bioavailability was calculated.

Improved hydrogen production with expression of hemH and lba genes in chloroplast of Chlamydomonas reinhardtii.

The coding region of both the ferrochelatase gene, hemH, from Bradyrhizobium japonicum, and the leghemoglobin gene, lba, from Glycine max, were transferred into chloroplast of Chlamydomonas reinhardtii. As a result, transgenic C. reinhardtii cultures more rapidly consumed O(2) and increased H(2) output compared with controls in both sulfur-free and sulfur-containing medium. H(2) production of the transgenic algal cultures in sulfur-free medium was 4-fold greater than that of control cultures, approximately 3.3mlbottle(-1). Maximum expression of the hemH-lba fusion protein on day 5 coincided with the lowest levels of O(2) content and the highest H(2) evolution rate detected over 7 days of anaerobic induction in sulfur-free medium. When the concentration of sulfate in the growth medium was restored to 12.5 or 50microM, O(2) consumption and H(2) yield decreased more slowly in the transgenic algal cultures than in the control cultures. These results demonstrate that expression of the hemH-lba fusion protein in chloroplast of C. reinhardtii improved their H(2) yield by decreasing O(2) content in the medium, thereby representing the potential for H(2) production in green algae to be improved.

Heavy-metal removal from aqueous solution by fungus Mucor rouxii.

Biosorption of lead, cadmium, nickel and zinc by live and dead Mucor rouxii biomass treated with NaOH was studied over a range of pH. In the case of dead biomass, low pH resulted in a decrease in the biosorption capacity. At pH 3.0 or less, the inhibition of biosorption of metal ions took place. At pH 4.0 or higher, the biosorption of metal ions increased sharply. Ho's pseudo-second-order model described the biosorption kinetics better than the Lagergren model. Live biomass had high biosorption capacity, i.e. 35.69, 11.09, 8.46 and 7.75 mg/g at pH 5.0 for Pb(2+), Ni(2+), Cd(2+) and Zn(2+), respectively. The dead biomass adsorbed metal ions in the order of Pb(2+), Zn(2+), Cd(2+) and Ni(2+), with the biosorption capability of 25.22, 16.62, 8.36 and 6.34 mg/g at pH 5.0, respectively. At pH 6.0, the capacity of the dead biomass increased to 53.75, 53.85, 20.31 and 20.49 mg/g, respectively. For bi- or multi-metal ion adsorption, biosorption capacity of individual metal ion was reduced in the presence of other metal ions, but the total biosorption capacity increased, indicating the capability of M. rouxii biomass in adsorbing multi-metal ions. In addition, M. rouxii biomasses cultured with different media exhibited the same level of capacity to bind metal ions. Metal ions adsorbed by the biomass could be eluted effectively with HNO(3), while distilled water demonstrated negligible metal elution capability. Regeneration of the biomass with NaOH regained or enhanced the biosorption capacity even after five cycles of adsorption-elution-regeneration.