Surface change of microplastics in aquatic environment and the removal by froth flotation assisted with cationic and anionic surfactants.

Microplastics (MPs) are increasingly released into the environment due to the widespread usage and improper management of plastics. Considerable research efforts have been devoted to the remediation of MPs. Froth flotation has been demonstrated as an effective method to remove MPs in water and sediment. However, there is a lack of knowledge on the regulation of the hydrophobicity/hydrophilicity of MPs surfaces. We found that exposure to the natural environment resulted in the increased hydrophilicity of MPs. The flotation efficiencies of polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), and polyethylene glycol terephthalate (PET) MPs decreased to zero after six months of natural incubation in rivers. According to various characterizations, the hydrophilization mechanism is mainly correlated with surface oxidation and the deposition of clay minerals. Inspired by surface wettability conversion, we applied surfactants (collectors) to enhance MPs hydrophobicity and flotation efficiency. Anionic sodium oleate (NaOL) and cationic dodecyl trimethyl ammonium chloride (DTAC) were used to regulate surface hydrophobicity. The effects of collector concentration, pH, conditioning time, and metal ions on MPs flotation were thoroughly elucidated. Characterizations and adsorption experiments were performed to describe the heterogeneous adsorption of surfactants on MPs surfaces. The interaction between surfactants and MPs was explained through density functional theory (DFT) simulations. The dispersion energy between hydrophobic hydrocarbon chains attracts collectors on the MPs surface, and the collector molecules wrap and laminate to MPs surfaces. Flotation using NaOL exhibited a higher removal efficiency, and NaOL was environmentally friendly. Subsequently, we investigated the activation of Ca2+, Fe3+, and Al3+ to further improve the collecting efficiency of NaOL. Under the optimized conditions, MPs in natural rivers could be removed by froth flotation. This study shows the great promise of froth flotation for the application of MPs removal.

Insight into the microplastics release from disposable face mask: Simulated environment and removal strategy.

The fight against the COVID-19 epidemic significantly raises the global demand for personal protective equipment, especially disposable face masks (DFMs). The discarded DFMs may become a potential source of microplastics (MPs), which has attracted much attention. In this work, we identified the detailed source of MPs released from DFMs with laser direct infrared spectroscopy. Polypropylene (PP) and polyurethane (PU) accounted for 24.5% and 57.1% of released MPs, respectively. The melt-blown fabric was a dominant MPs source, however, previous studies underestimated the contribution of mask rope. The captured polyethylene terephthalate (PET), polyamide (PA), polyethylene (PE), and polystyrene (PS) in airborne only shared 18.4% of released MPs. To deepen the understanding of MPs release from medical mask into the aquatic environment, we investigated the effects of environmental factors on MPs release. Based on regression analysis, the effects of temperature, incubation time, and wearing time significantly affect the release of MPs. Besides, acidity, alkalinity, sodium chloride, and humic acid also contributed to the MPs release through corroding, swelling, or repulsion of fibers. Based on the exposure of medical mask to simulated environments, the number of released MPs followed the order: seawater > simulated gut-fluid > freshwater > pure water. Considering the risk of MPs released from DFMs to the environment, we innovatively established a novel flotation removal system combined with cocoamidopropyl betaine, achieving 86% removal efficiency of MPs in water. This work shed the light on the MPs release from DFMs and proposed a removal strategy for the control of MPs pollution.

Stepwise flotation separation of WEEE plastics by polymeric aluminum chloride towards source control of microplastics.

The mismanagement of waste electrical and electronic equipment (WEEE) resulted in numerous discarded plastics in the natural environment, and these waste plastics might experience aging, breaking, and migration, which becomes a crucial microplastic source. Sustainable management of WEEE plastics presents a considerable opportunity for resource recovery and microplastic pollution prevention. Flotation separation is a significant process of mechanical recycling, while most flotation methods can only deal with binary plastic mixtures. In this work, an advanced, stepwise, and sustainable flotation method was advocated to separate multi-plastics by polymeric aluminum chloride (PAC) modification. The abundant hydrophilic groups and environmental friendliness of PAC prompted us to further investigate the wetting effect. PAC had varied hydrophilization effects on acrylonitrile butadiene styrene (ABS) and polystyrene (PS) surfaces, but polyethylene terephthalate (PET) retained hydrophobicity. Treatment conditions, including PAC dosage, temperature, time, and pH were optimized. 100% of PET could be purified after primary separation, and the purities of ABS and PS could reach 100% and 97.4% after secondary separation, respectively. The strength of the interaction was determined by the different surface potentials and functional groups. In PAC solution, long-chain molecules or ions might interact with plastic surfaces electrostatically, and Al3+ could bridge long-chain molecules and plastic surfaces, thereby strengthening the polymer hydrophilicity. We further improved the PAC treatment process, and the reuse of PAC reduced modifier usage to 84.4 g/ton waste plastics, which was cost-effective in industrial applications. A preliminary evaluation of the energy consumption and environmental impact indicated that PAC treatment was superior to other modification methods. This work is an initial attempt at the stepwise separation of waste plastic and shows promising prospects for recycling plastic waste.

Association of Serum Magnesium with Insulin Resistance and Type 2 Diabetes among Adults in China.

Magnesium is an essential mineral for the human body and a cofactor or activator for more than 300 enzymatic reactions, including blood glucose control and insulin release. Diabetes is a well-known global burden of disease with increasing global prevalence. In China, the prevalence of diabetes in adults is higher than the global average. Evidence shows that magnesium is a predictor of insulin resistance and diabetes. However, the majority of studies focus on dietary magnesium instead of serum magnesium concentration. We study the correlation of serum magnesium levels with insulin resistance and Type 2 diabetes. In this prospective cohort study, we included 5044 participants aged 18 years and older without insulin resistance (IR) and diabetes at the baseline from China Health and Nutrition Survey (CHNS). A fasting blood sample was taken for the measurement of both types of magnesium, fasting blood glucose, hemoglobin A1c (HbA1c), and fasting insulin. The homeostatic model (HOMA-IR) was calculated. Demographic characteristics of participants, and risk factors such as intensity of physical activities, smoking status, drinking habit, and anthropometric information were recorded. IR was defined as HOMA-IR ≥ 2.5, and Type 2 diabetes mellitus was defined as fasting plasma glucose ≥ 7.0 mmol/L or HbA1c ≥ 6.5%, or a self-reported diagnosis or treatment of diabetes. A total of 1331 incident insulin resistance events and 429 incident diabetic events were recorded during an average follow-up of 5.8 years. The serum magnesium concentration was categorized into quintiles. After adjusting for relevant covariates, the third quintile of serum magnesium (0.89−0.93 mmol/L) was correlated with 29% lower risk of incident insulin resistance (hazard ratio = 0.71, 95% CI 0.58, 0.86) and with a lower risk of Type 2 diabetes. Multivariable-adjusted hazard ratios (95% confidence intervals) for insulin resistance were compared with the lowest quintile of serum magnesium (<0.85). We found similar results when evaluating serum magnesium as a continuous measure. Restricted cubic spline (RCS) curves showed a nonlinear dose−response correlation in both serum magnesium levels and insulin resistance, and in serum magnesium levels and Type 2 diabetes. Lower serum magnesium concentration was associated with a higher risk of insulin resistance and diabetes.

[Snacking behaviors of Chinese female adults aged 18 to 49 years old in 2004-2015].

OBJECTIVE: To describe shift in snacking behavior among Chinese female adults aged 18 to 49 years old in 2004-2015, and to analyze the contribution of snacks to energy and nutrients among them. METHODS: The present study used data from "China Health and Nutrition Health" where a multistage stratified cluster design was employed to select a stratified probability sample. A total of 12 523 female participants aged 18-49 years old who participated in surveys conducted in 2004-2015 with completed data of demographic characteristics and dietary measurementswere selectedas subjects. There were 2376, 2149, 2142, 2844 and 3012 subjects in waves of 2004, 2006, 2009, 2011, and 2015, respectively. Multivariate Logistic regression model was used to analyze the relationship between socioeconomic factors and snack consumption. Generalized linear model was used to analyze the energy and nutrient intake of snack consumers and non-snack consumers, as well as the contribution of snacks to energy and nutrients. RESULTS: The consumption rate of snacking for women aged 18 to 49 years old had an increasing trend over time(P<0.05), and the rate was 14.24% in 2015, 3.5 times as high as that in 2004. Participants aged 18 to 29 years old whose snake consumption rates were relatively higher compared to those of other aged groups in general waves; also, female adults from the higher education group, the higher yearly income group, and the higher urbanicity index group, and those with the history of smoking or the alcohol use tended to consumed snacks. The change of the influential factors in relation to the consumption of the participant's snack was observed, and age, income level, education level, living area, and the behavior of smoking and drinking were all important factors of snacking. The daily energy and nutrient intake of female snack consumers aged 18 to 49 years old was higher than that of non-snack consumers. The contribution rate of snacks to energy and nutrients varies significantly between survey years; and the contribution of snacks to energy and main nutrients was more than 20% in 2011. CONCLUSION: Snacks have become an important part of the diet of Chinese women aged 18 to 49 years old. Future health promotion programs should be targeted on nutrition education and intervention to guide a reasonable diet structure.

A comparison of the Mini-Mental State Examination (MMSE) with the Montreal Cognitive Assessment (MoCA) for mild cognitive impairment screening in Chinese middle-aged and older population: a cross-sectional study.

BACKGROUND: The Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) are the most commonly used scales to detect mild cognitive impairment (MCI) in population-based epidemiologic studies. However, their comparison on which is best suited to assess cognition is scarce in samples from multiple regions of China. METHODS: We conducted a cross-sectional analysis of 4923 adults aged ≥55 years from the Community-based Cohort Study on Nervous System Diseases. Objective cognition was assessed by Chinese versions of MMSE and MoCA, and total score and subscores of cognitive domains were calculated for each. Education-specific cutoffs of total score were used to diagnose MCI. Demographic and health-related characteristics were collected by questionnaires. Correlation and agreement for MCI between MMSE and MoCA were analyzed; group differences in cognition were evaluated; and multiple logistic regression model was used to clarify risk factors for MCI. RESULTS: The overall MCI prevalence was 28.6% for MMSE and 36.2% for MoCA. MMSE had good correlation with MoCA (Spearman correlation coefficient = 0.8374, p < 0.0001) and moderate agreement for detecting MCI with Kappa value of 0.5973 (p < 0.0001). Ceiling effect for MCI was less frequent using MoCA versus MMSE according to the distribution of total score. Percentage of relative standard deviation, the measure of inter-individual variance, for MoCA (26.9%) was greater than for MMSE (19.0%) overall (p < 0.0001). Increasing age (MMSE: OR = 2.073 for ≥75 years; MoCA: OR = 1.869 for≥75 years), female (OR = 1.280 for MMSE; OR = 1.163 for MoCA), living in county town (OR = 1.386 and 1.862 for MMSE and MoCA, respectively) or village (OR = 2.579 and 2.721 for MMSE and MoCA, respectively), smoking (OR = 1.373 and 1.288 for MMSE and MoCA, respectively), hypertension (MMSE: OR = 1.278; MoCA: OR = 1.208) and depression (MMSE: OR = 1.465; MoCA: OR = 1.350) were independently associated with greater likelihood of MCI compared to corresponding reference group in both scales (all p < 0.05). CONCLUSIONS: MoCA is a better measure of cognitive function due to lack of ceiling effect and with good detection of cognitive heterogeneity. MCI prevalence is higher using MoCA compared to MMSE. Both tools identify concordantly modifiable factors for MCI, which provide important evidence for establishing intervention measures.

A clean and efficient flotation towards recovery of hazardous polyvinyl chloride and polycarbonate microplastics through selective aluminum coating: Process, mechanism, and optimization.

Polyvinyl chloride (PVC) and polycarbonate (PC) microplastics are major sources of hazardous chlorine and bisphenol A, threatening the ecosystem and environment. Plastic recycling can control the source of microplastics pollution, but the recycling of PVC and PC will be prevented by invalid separation. We established a novel and clean flotation method to separate PVC and PC microplastics by using aluminum coating. Trace amounts of Al(OH)3 can selectively coat the PVC microplastics surface due to its strong affinity for PVC. The contact angle of PVC decreases by 24° due to abundant hydroxyl groups of Al(OH)3 coating, whereas PC remained hydrophobic. Response surface methodology (RSM) combining Box-Behnken design (BBD) is used to optimize modification. A quadratic model is established to predict PC purity, explore the interaction between pH, aluminum chloride concentration, and ultrasonic duration. The recovery and purity of microplastics can exceed 99.65% with parameter optimization. The effects of multi-component, brand, shape, size, and mass ratio of plastics are utilized to evaluate the application potential. The suitable situations and limits of this method are disclosed. The aluminum coating offers significant benefits over other modifications in terms of reaction temperature, treatment time, and pollution prevention. Flotation based on aluminum coating provides a new insight for separating and recycling microplastics.

Hydrophilic modification of polycarbonate surface with surface alkoxylation pretreatment for efficient separation of polycarbonate and polystyrene by froth flotation.

Waste polystyrene (PS) and polycarbonate (PC) are crucial components arising from mixtures of plastic products, whose recycling is significantly limited by separation efficiency. In this work, to assist the flotation separation of PC and PS, we proposed a novel modification technology of surface alkoxylation pretreatment (SAP) where PC surface reacted with glycerol and urea. The SAP could selectively transform the hydrophobic PC into hydrophilic plastic, while the PS remained its hydrophobic surface owing to the exclusion from SAP process. Benefiting from the hydrophilic PC, the separation efficiency of PS and PC could reach the maximum of 99.34% under optimum conditions (urea dosage of 5 g, pretreatment temperature of 130 °C, pretreatment time of 10 min, flotation time of 2.5 min, frother concentration of 16.5 mg/L, and airflow rate of 7.2 mL/min). The mechanism of SAP was systematically analyzed by wettability, surface morphology, molecular weight, and chemical reactions. Compared with PS plastic, the pretreated PC presented better wettability, rougher surface, and significantly reducing molecular weight. The improvement of PC hydrophilicity can be attributed to the cleavage of ester bonds on backbone chains and the introduction of hydrophilic hydroxyl groups. The effective SAP process proves that chemical recycling of waste plastic can provide a novel strategy for surface modification and flotation separation of PS and PC.

[Perceived stress level and its related factors in Chinese adult residents aged 18-65 in 15 provinces (autonomous regions and municipalities) in 2015].

OBJECTIVE: To investigate the perceived stress prevalence of adult residents aged 18-65 in 15 provinces(autonomous regions and municipalities) and its related factors. METHODS: Adults aged 18 to 65 years, with middle school education or above and complete demographic and socioeconomic characteristics, lifestyle, disease history and physical measurements were selected as study subjects from the database of Nutritional Status and Health Transition of Chinese Residents Project in 2015. Chinese perceived stress scale(CPSS) was used to evaluate the perceived stress level of participants, and percentile regression model was used to analyze the correlation between related factors and perceived stress. RESULTS: A total of 6679 subjects were enrolled in this study. The mean and median of perceived stress scores were 22. 6 and 24. 0, respectively. The percentile regression model showed that age was positively associated with perceived stress in the 5 th, 25 th, 50 th and 95 th percentiles, and the difference between the two groups decreased with the increase of perceived stress score(P5, ß=1. 31, 95%CI 0. 38-2. 24; P25, ß=0. 91, 95%CI 0. 28-1. 53). Compared with the control group, adults with junior high school education had a high level of perceived stress in higher percentiles(P50, ß=0. 81, 95%CI 0. 32-1. 30; P75, ß=0. 42, 95%CI 0. 11-0. 72; P95, ß=0. 62, 95%CI 0. 06-1. 18). Perceived stress levels in the 50 th, 75 th and 95 th percentiles were lower in the married adults than in the control group(P50, ß=-0. 81, 95%CI-1. 40--0. 23; P75, ß=-0. 39, 95%CI-0. 68--0. 10; P95, ß=-0. 95, 95%CI-1. 79--0. 12). In the 5 th, 25 th, 50 th and 75 th percentiles, the perceived stress level of no workers is higher than that of workers, and the difference decreases with the increase of perceived stress score(P5, ß=1. 31, 95%CI 0. 32-2. 31; P75, ß=0. 53, 95%CI 0. 35-0. 71). Income level showed a positive association with perceived stress across the entire conditional perceived stress distribution(P<0. 05). People with low levels of physical activity had higher levels of perceived stress in the 25 th, 50 th, and 75 th percentiles than the control group(P25, ß=1. 15, 95%CI 0. 41-1. 90; P50, ß=1. 09, 95%CI 0. 62-1. 56; P75, ß=0. 28, 95%CI 0. 07-0. 49). Urbanization level and alcohol consumption and other factors had influence on perceived stress in different percentile(P<0. 05). No significant correlation was found between housing ownership, smoking, sleep duration and perceived stress. CONCLUSION: The perceived stress level of adult residents aged 18 to 65 in 15 provinces of China is on the high level on the whole, which is correlated with age, marital state employment, annual per capita income, physical activity level and other factors.

[Effect of dietary cholesterol intake on stroke incidence among Chinese adults: evidence from China Health and Nutrition Survey].

OBJECTIVE: To examine the longitudinal association between dietary cholesterol intake and stroke incidence in Chinese adults. METHODS: The data were from 5833 non-stroke participants aged 30-98 in 1997 and more than one repeated measurements in the following five waves (2000, 2004, 2006, 2009 and 2011) of the China Health and Nutrition Survey. 5805 participants were included eventually after removing those with abnormal dietary cholesternul intake. Dietary cholesterol and energy intake was assessed with 3 d - 24 h dietary recalls in all the waves. Self-reported hypertension, diabetes mellitus, alcohol drinking, smoking, and standardized measurement of waist circumstance were collected also. Time-dependent Cox proportional hazard regression models were constructed to estimate relative risks (RR) with 95% confidence intervals (CI). RESULTS: During the mean 11. 3 years follow-up, 198 stroke events of 5805 participants were ascertained. The quintiles dietary cholesterol intake were 70.0, 146.9, 218.3, 297.8 and 425.9 mg/d. After adjusted for potential confounders, the time-dependent cholesterol intake, baseline cholesterol intake and the mean cholesterol intake during 1997-2011 were insignificantly associated with stroke. The relative risks and 95% confidence intervals were 1. 000 (0.999 - 1.001), 1.000 (0.999 - 1.001 ) and 0.999 (0.998 - 1.001) respectively. The cholesterol intake quintiles were insignificantly associated with stroke incidence. The relative risks and 95% confidence intervals versus lowest quintile were 0.812 (0.504 - 1.310), 0.644 (0.389 - 1.066) 0.913 (0.576 - 1.446) and 0.692 (0.416 - 1.152) respectively. CONCLUSION: Effect of dietary cholesterol intake on stroke incidence might was insignificant in Chinese adults.

[Analysis of physical activity and sedentary behaviors in children and adolescents from 12 provinces/municipalities in China].

OBJECTIVE: To evaluate the pattern and level of physical activity (PA) and sedentary behaviors in Chinese children and adolescents. METHODS: The data of present study were derived from China Health and Nutrition Survey in 2011. Subjects aged 7-18 years with completed demographic, PA and sedentary behavior data were included to analyze the proportions of participations in PA outside school, PA in school, domestic PA, PA in travel and sedentary behaviors. In subjects with PA and sedentary behaviors, PA and sedentary behavior levels were estimated by age, gender, residence areus and household income. RESULTS: Amony the five types of activities studies, the proportion of children and adolescents with sedentary behaviors was highest (97.9%), while that of PA outside school was lowest (33.6%), the distribution of participations of various PA and sedentary behaviors were similor regardless of age and gender. The median levels of PA outside school and sedentary behaviors in children and adolescents having corresponding activities were the highest, 39.9 and 36.1 MET-h/week, respectively, which suggested that the time on sedentary behaviors was long. The differences in levels of various PA and sedentary behaviors by age, gender and residence were observed (all P < 0.05). CONCLUSION: In general, PA is deficient in Chinese children and adolescents. The promotion programmes to increas PA level need to be strengthened.

Combined effects of cyclooxygenase-1 and cyclooxygenase-2 selective inhibitors on ovarian carcinoma in vivo.

The present study was designed to investigate the combined effects of cyclooxygenase (COX)-1 and COX-2 selective inhibitors on human ovarian SKOV-3 carcinoma cells xenograft-bearing mice. The animals were treated with 3 mg/kg SC-560 (a COX-1 selective inhibitor) alone, 25 mg/kg celecoxib (a COX-2 selective inhibitor) alone, or SC-560/celecoxib by gavage, twice a day for three weeks. To test the mechanism of inhibition of tumor growth by COX selective inhibitors, the index of proliferating cells in tumor tissues was determined by immunostaining and the index of apoptotic cells by the terminal-deoxynucleotidyl-transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) method. The inhibitory rate on tumor growth in the combination group was 35.54% which is significant statistically compared with that of the control group (P < 0.05). In the combination group, the index of cell proliferation and apoptosis were 12.40% and 51.03% respectively, which are significant statistically compared with those of the control group (22.56%, 19.07%, all P < 0.05). These studies indicate that synergism between two COX inhibitors and inhibitor combination treatment has particular potential for chemoprevention of ovarian cancer growth.

Cyclin D1 expression and the inhibitory effect of celecoxib on ovarian tumor growth in vivo.

The report aims to investigate the relationship between the expression of cyclin D1 and Cyclooxgenase-2 (COX-2), thus to explore the molecular mechanisms of the antitumor efficacy of Celecoxib, a COX-2 inhibitor. Human ovarian SKOV-3 carcinoma cell xenograft-bearing mice were treated with Celecoxib by infusing gaster (i.g.) twice/day for 21 days. The mRNA levels of COX-2 and cyclin D1 were determined by RT-PCR. The expression of cyclin D1 at the protein level was detected by immunohistochemistry, while COX-2 protein expression was determined by Western blot. A high-dose of Celecoxib (100 mg/kg) significantly inhibited tumor growth (P < 0.05), and the expression of cyclin D1 was reduced by 61%. Celecoxib decreased the proliferation cell index by 40% (P < 0.001) and increased apoptotic index by 52% (P < 0.05) in high-dose Celecoxib treated group. Our results suggest that the antitumor efficacy of Celecoxib against ovarian cancer in mice may in part be mediated through suppression of cyclin D1, which may contribute to its ability to suppress proliferation.

Effects of a selective cyclooxygenase-1 inhibitor in SKOV-3 ovarian carcinoma xenograft-bearing mice.

To evaluate the effect of a cyclooxygenase-1 (COX-1) inhibitor, SC-560, on the growth inhibition of s.c. human ovarian SKOV-3 carcinoma and on angiogenesis. Human ovarian SKOV-3 carcinoma cells xenograft-bearing mice were treated with SC-560, a COX-1-selective inhibitor, 6 mg/kg alone i.g. daily, and i.p. injections of cisplatin 3 mg/kg every other day for 21 days. Prostaglandin E(2) (PGE(2)) levels were determined by ELISA. Microvessel density (MVD) of ovarian carcinoma was determined with anti-CD(34) as the label by immunohistochemistry. In addition, the expression of COX-1 at protein levels in the control group was detected by immunohistochemistry. SC-560 reduced the growth of tumors when SKOV-3 cells were xenografted in nude female mice. The inhibitory rates in SC-560 group and cisplatin group were 47.1% and 51.7%, respectively, which is significant statistically compared to that of control group (all, P < 0.05). In treatment groups, SC-560 significantly reduced intratumor PGE(2) levels (P < 0.01). MVDs in SC-560 group were 35.73 +/- 9.87, which are significant statistically compared to that of control group (74.33 +/- 9.50) (P < 0.01). COX-1, not COX-2, protein levels are elevated in tumor tissues. These findings may implicate COX-1 as a suitable target for the treatment of ovarian cancer and that antiangiogenic therapy can be used to inhibit ovarian cancer growth.