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If there was abundant fluorine in shotcrete, it might leach out and pollute the soil or migrate to corrode the reinforcement.Therefore, this research mainly investigated the basic properties of high-fluorine alkali free liquid accelerator (HF-AFA) and its occurrence forms in cement hydration products.The macro-test results showed that with the increase of HF-AFA dosage, it appeared excellent coagulation promoting property. However, when the HF-AFA dosage exceeded 7.0%, the 1d compressive strength of mortar was lower than 7.0 MPa. In addition, by measuring the early hydration heat of cement, C3A, C3S, C2S and C4AF pastes with and without HF-AFA, and combining XRD and SEM micro-analysis, the occurrence forms of fluorine in different clinker minerals were obtained.The final analysis results indicated that fluorine mainly existed in the form of CaF2, CaAlF5 and Ca2AlF7 crystals in C3A and C3S minerals, while only little CaF2 crystals appeared in C2S and C4AF minerals. [ABSTRACT FROM AUTHOR]

Interests in evaluation of the effect of air pollution and weather conditions on cardiovascular disease have increased. However, the relationship between short-term particulate matter (PM) exposure and first incident ST-elevation myocardial infarction (STEMI) remains unclear. Medical records were collected from December 2013 to December 2016. A total of 1354 patients with first incident STEMI were included. The daily average of air pollution and weather conditions were calculated. In this case-crossover study, conditional logistic regression was performed to assess the association between daily concentrations of PM and first incident STEMI. The daily average of PM2.5 and PM10 were 58.9 μg/m3 and 80.2 μg/m3, respectively. In this case-crossover study, single-pollutant models showed that each 10 μg/m3 increase in PM2.5 was associated with a percent change of 3.36, 95% confidence interval (CI): (1.01–5.77), or in PM10 percent change of 2.1%, 95%CI: (0.2–4.04) for patients with first incident STEMI. The association remained stable after adjusting for ozone (O3). The results from subgroup analysis showed the association slightly enhanced in women, elder patients, patients with history of diabetes, patients without history of smoking, and cold seasons. The p values were not significant between these strata, which may be due to small sample size. This investigation showed that short-term PM exposure associated with first incident STEMI in Suzhou. Given the effect of PM on the first incident STEMI, strategies to decrease PM should be considered. [ABSTRACT FROM AUTHOR]

Due to the rapid economic development and acceleration of industrialization, most cities in China are experiencing severe air pollution. Exposure to fine particulate matter (PM2.5) has been associated with acute lower respiratory tract infection (ALRI). To estimate associations between short-term exposure to PM2.5 and ALRI hospitalization in Yancheng City, China. This was a 6-year time-series study from 2014 to 2019. Data on hospitalization were collected from four high-ranked general hospitals, including for community-acquired pneumonia (CAP), acute exacerbation of chronic bronchitis (AECB), acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and acute exacerbation of bronchiectasis (AEB), and the sum was termed total ALRIs. We obtained pollutant exposure data from five fixed monitoring stations. The association between PM2.5 and ALRI hospitalization was estimated using the generalized linear model with quasi-Poisson regression. Two-pollutant models were applied to test the robustness of the observed correlations. Subgroup analyses included sex, age, and season. During the study period, a total of 43,283 cases of total ALRIs were recorded. The average annual mean PM2.5 concentration was 45.4 ± 32.3 μg/m3. A 10-μg/m3 increase in PM2.5 concentration (lag 0) was significantly associated with increases in hospitalizations for total ALRIs (at 0.73%; 95% CI: 0.40%, 1.06%), in CAP (at 0.80%; 95% CI: 0.02%, 1.57%), in for AECOPD (1.08%; 95% CI: 0.38%, 1.78%), and AECB (0.67%; 95% CI: 0.23%, 1.11%). The estimated effects for total ALRIs and AECB were relatively robust with adjustment for other air pollutants. Associations between PM2.5 and total ALRIs were stronger in females, in the elderly, and in the cold season. PM2.5 exposure was significantly associated with ALRI morbidity, and females and older people were more susceptible to PM2.5 air pollution, especially in the cold season. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) in natural environments have attracted lots of attention. Although the quantity of MPs present in terrene is much higher than that in aquatic environment, few studies have investigated the chemical behavior of MPs in terrestrial environment. This study investigate the Cu2+ (as a model heavy metal) adsorption capacity of six kinds of MPs (polyamide-6 (PA), polyethylene (PE), polystyrene (PS), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA)) in batch adsorption experiments and the effects of different soil environmental factors, including pH and the presence of cations and low-molecular-weight organic acids (LMWOAs), as well as ultraviolet (UV) aging. The Cu2+ adsorption capacities of PA and PMMA were higher than those of other MPs and their maximum equilibrium adsorption capacities (estimated by the Langmuir adsorption equation) were 323.6 μg/g ± 38.2 and 41.03 ± 1.78 μg/g, respectively. The Cu2+ adsorption on MPs was affected by pH, and the greatest amount of Cu2+ adsorbed on PA and PMMA was observed at pH = 6 and pH = 7, respectively. The presence of Ca2+ or Mg2+ inhibited Cu2+ adsorption by MPs, due to competition for the adsorption sites. Moreover, Cu2+ adsorption by MPs was affected by various types of LMWOAs. The Cu2+ adsorption on PA was significantly reduced by citric acid, followed by oxalic acid, and oxalic acid was particularly evident for Cu2+ adsorption on PMMA. UV aging (200 h) had different effect on Cu2+ adsorption on MPs and it depends on the change of carbonyl index. Results demonstrate that soil environmental factors can change the ability of different MPs to adsorb Cu2+ and affect the transport of pollutants as carriers. [ABSTRACT FROM AUTHOR]

Limited information about the sludge quality is a major constraint for its usage and proper disposal. This study investigated the occurrence of 49 elements in sludge from 11 wastewater treatment plants (WWTPs) in Chongqing and Xiamen cities of China. The concentration of 46-detected elements ranged from 16.2 μg kg−1 (Pt) to 55.0 g kg−1 (Al) on dry solid basis in the sludge. The enrichment factor of most of the elements was > 1.5, indicating their possible anthropogenic origin. The precious metals had considerably higher enrichment factor ranging from 56.3 to 200,000. Principal component analysis clustered the samples from Chongqing and Xiamen separately to suggest strong spatial variations. Contamination factor, pollution loading index, and integrated pollution degree were calculated to evaluate the elemental pollution risk. The pollution loading index indicated unpolluted to highly polluted levels of the elements in the sludge. In addition, results from the ecotoxicological risk index showed an individual low to very high ecotoxicological risk posed by eight metal(loid)s (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in the WWTPs. [ABSTRACT FROM AUTHOR]

Cigarette smoke causes insulin resistance, which is associated with type 2 diabetes mellitus (T2DM). However, the mechanism by which this occurs remains poorly understood. Because the involvement of microRNAs (miRNAs) in the development of insulin resistance is largely unknown, we investigated, in hepatocytes, the roles of miR-191 in cigarette smoke extract (CSE)-induced insulin resistance. In L-02 cells, CSE not only decreased glucose uptake and glycogen levels but also reduced levels of insulin receptor substrate-1 (IRS-1) and Akt activation, effects that were blocked by SC79, an activator of Akt. CSE also increased miR-191 levels in L-02 cells. Furthermore, the inhibition of miR-191 blocked the decreases of IRS-1 and p-Akt levels, which antagonized the decreases of glucose uptake and glycogen levels in L-02 cells induced by CSE. These results reveal a mechanism by which miR-191 is involved in CSE-induced hepatic insulin resistance via the IRS-1/Akt signaling pathway, which helps to elucidate the mechanism for cigarette smoke-induced T2DM. [ABSTRACT FROM AUTHOR]

Type 2 diabetes (T2D) is a chronic disease caused by pancreatic β-cell dysfunction and insulin resistance. Exposure to smoke is a risk factor for diabetes; however, its mechanisms are unclear. In an epidemiological study, we determined the relationship between cigarette smoking and β-cell function. T2D patients had a history of heavier smoking than people without T2D, and heavy smokers had more abnormal glucose metabolism. For various smoking populations, there was a dose-effect relationship between decreases of homeostatic model assessment (HOMA)-β levels or the increases of HOMA-insulin resistance (IR) levels and amount of smoking (pack-years), which indicated that smoking induced β-cell dysfunction. For MIN6 cells, cigarette smoke extract (CSE) decreased insulin secretion and content; enhanced apoptosis, as illustrated by decreases of BCL-2 levels, increases of BAX and cleaved caspase-3 levels, and an increased apoptotic index; and activated the p38 MAPK pathway. For MIN6 cells, inhibition of p-p38 MAPK by SB203580 prevented enhanced apoptosis and the dysfunction of insulin secretion induced by CSE. In sum, activation of p38 MAPK is involved in the apoptosis of pancreatic β-cells induced by cigarette smoking, which is a possible mechanism for induction of T2D by cigarette smoke. [ABSTRACT FROM AUTHOR]