Various ratios of beta-Bi.sub.2O.sub.3/Bi.sub.2O.sub.2CO.sub.3 composites were successfully synthesized through solvothermal method which were characterized by XRD, UV-Vis DRS, SEM and XPS. The ...photocatalytic degradation of bisphenol A (BPA) demonstrated that both solvothermal and calcination temperatures significantly affected the photocatalytic activity of the prepared composites. The optimal photocatalytic performance was achieved at a solvothermal temperature of 180°C and a calcination temperature of 300°C under simulated sunlight irradiation with a 500 W xenon lamp. The characterization of the photocatalysts revealed that beta-Bi.sub.2O.sub.3/Bi.sub.2O.sub.2CO.sub.3 with diverse solvothermal temperatures exhibited a rose-like structure, and almost all materials possessed a wide absorption range from UV to visible light. A larger specific surface area is expected to provide more active sites and improve the photocatalytic activity of the materials. A narrower band gap would expedite the combination of e.sup.- and h.sup.+ and inhibit the photocatalytic process. The high photocatalytic activity of beta-Bi.sub.2O.sub.3/Bi.sub.2O.sub.2CO.sub.3 is primarily attributed to the phase transition from Bi.sub.2O.sub.2CO.sub.3 to beta-Bi.sub.2O.sub.3. In addition, the active species were detected by ESR with DMPO as a trap, and simultaneous trapping experiments were performed. The comprehensive analysis suggested that both h.sup.+ and ·O.sub.2.sup.- were the photocatalytically active species. The photocatalytic mechanism is proposed that the p-n heterojunction structure of beta-Bi.sub.2O.sub.3/Bi.sub.2O.sub.2CO.sub.3 accelerates the transfer of e.sup.- and h.sup.+.
The secondary-proton polarization and differential cross sections for the (p, p') inelastic reaction on sup.28Si and sup.56Fe nuclei at the initial proton energy of 1 GeV were measured over a wide ...range of the scattered-proton momenta at a laboratory angle of 0 = 21degrees. Scattered protons were detected by means of a magnetic spectrometer equipped with a polarimeter based on multiwire proportional chambers and a carbon analyzer. A structure in the polarization and cross section data, which is probably related to quasielastic scattering off nucleon correlations in the sup.28Si and sup.56Fe nuclei, was observed as earlier in the analogous data for sup.12C and sup.40Ca nuclei. Momentum intervals within which cross- section ratios for nuclei did not depend on the scattered-proton momentum were found. DOI: 10.1134/S1063778818030171
The possibility of removing bisphenol A and its five potential substitutes (bisphenols S, F, AF, E, and B) was tested using microorganism consortia from river water and activated sludge from ...municipal and rural wastewater treatment plants. For most bisphenols, biodegradation with activated sludge was faster than with river water and a greater extent of biodegradation was also achieved. However, only bisphenol A and bisphenol F underwent 100% primary biodegradation while other bisphenols degraded no more than about 50% which has some important implications in case of their increased usage. Metabolic activity in biodegradation liquors was also tested and it showed higher activity in the tests with activated sludge than with river water. However, there was no clear connection between the decline of metabolic activity and the extent of biodegradation as decreased activity was observed for two easily degrading bisphenols and two others with little biodegradability. It can be assumed that two different phenomena are involved in this process including depletion of nutrients for easily degradable bisphenol A and absence of nutrients for bacteria incapable of primary degradation of bisphenol AF and bisphenol S.
We study the Cauchy problem of the quasilinear evolution equations in L.sup.P.sub.mu-spaces. Based on the theories of maximal L.sup.p-regularity of sectorial operators, interpolation spaces, and ...time-weighted L.sup.p-spaces, we establish the local posedness for a class of abstract quasilinear evolution equations with lower regular initial data. To illustrate our results, we also deal with the second-order parabolic equations and the Navier-Stokes equations in L.sup.p,q-spaces with temporal weights.
•Low-dose BPA exposure caused adverse reproductive effects in animal model.•Emerging evidence indicate BPA analogs exert unique reproductive toxicity in animal model.•Knowledge gaps and research ...needs have been identified for risk assessment.
Known endocrine disruptor bisphenol A (BPA) has been shown to be a reproductive toxicant in animal models. Its structural analogs: bisphenol S (BPS), bisphenol F (BPF), bisphenol AF (BPAF), and tetrabromobisphenol A (TBBPA) are increasingly being used in consumer products. However, these analogs may exert similar adverse effects on the reproductive system, and their toxicological data are still limited. This mini-review examined studies on both BPA and BPA analog exposure and reproductive toxicity. It outlines the current state of knowledge on human exposure, toxicokinetics, endocrine activities, and reproductive toxicities of BPA and its analogs. BPA analogs showed similar endocrine potencies when compared to BPA, and emerging data suggest they may pose threats as reproductive hazards in animal models. While evidence based on epidemiological studies is still weak, we have utilized current studies to highlight knowledge gaps and research needs for future risk assessments.
•A reliable method was developed for the analysis of four bisphenols in foodstuffs.•Plackett-Burman design and response surface methodology were used to determine the optimal conditions.•Dietary ...exposure assessment was performed combining the contamination monitoring data and daily food consumption.
An effective method has been developed for the simultaneous determination of four bisphenols (bisphenol A, S, F and B) in various foodstuffs. The contaminants were extracted by QuEChERS-based strategy and subjected to ion-exchange solid-phase extraction for further clean-up. The critical variables were screened by Plackett-Burman design and then optimized by central composite design. Under the optimized conditions, satisfactory accuracy (recoveries 76%–116%) and precision (RSDs < 12%) were achieved. The established method was then used to assess the contamination status of 379 real samples. Bisphenol A was demonstrated to be the predominant bisphenol with highest incidence (79.7%) and average concentration (14.3 μg/kg). The positive rates (mean concentration) of bisphenol S, F and B were 37.7% (1.6 μg/kg), 26.9% (1.4 μg/kg) and 0.0% (not detected), respectively. Finally, the daily dietary intakes of ∑4bisphenolsfor adult residents were estimated (55.9–76.1 ng/kg bw/day) according to the contamination concentrations and the daily recommended intakes.
Diet is regarded as the main source of bisphenol A (BPA) exposure, but comparatively little is known about dietary sources of BPA-alternatives. Here we measured exposure of BPA and BPA-alternatives ...among pregnant women in Canada, estimated their 24-h intakes and examined the importance of various dietary sources. Free and total BPA, bisphenol S (BPS) and bisphenol F (BPF) were measured in 467 second trimester maternal urine samples, and in 455 paired samples collected at three months postpartum. Linear regression was used to evaluate associations between urinary concentrations of bisphenols and 24-h dietary recall data. The geometric means of total BPA in second trimester and postpartum urine (1.2 and 0.95 ng/mL, respectively) were 5–7 times higher than corresponding total BPS (0.16 and 0.17 ng/mL). The detection frequency of BPF was only 9% (i.e. >1.0 ng/mL). However, at both time points 95th percentiles of total BPF (7.3 and 4.2 ng/mL, respectively) were similar to total BPA (8.2 and 5.0 ng/mL). Free BPS and BPF were detected in <2% of samples, but were detectable when total BPS or BPF concentrations were highest, always at <1% of the total concentration. The tolerable daily intake for total BPA (i.e. 18 nmol/kg BW/d) was not exceeded, but for BPS the estimated 24-h intake was as high as 14 nmol/kg BW/d (95th percentile: 0.12 nmol/kg BW/d), and for BPF was even higher among the highest centile of exposure (maximum and 95th percentile: 30, 0.81 nmol/kg BW/d). Canned food consumption was associated with higher total BPA, but was not associated with BPS. For BPF, mustard consumption may be an important exposure source, particularly among the highest exposed. Relatively high exposure to BPS and BPF in a minority of pregnant women highlights the need to better understand the associated health risks and exposure sources of BPA-alternatives.
•In highly exposed women, free BPS or BPF accounts for <1% of total BPS and BPF.•Highest estimated 24-h intake of BPS and BPF approach or exceed the TDI for total BPA.•Canned food consumption is associated with higher total BPA, but not so for BPS.•Mustard consumption may be an important exposure source for BPF.
•Exposures to BPA analogues in associations with serum hormones were examined.•Higher BPF and BPS exposures were associated with lower E2 levels and E2/T ratio.•Higher BPS exposure was associated ...with lower SHBG levels.•Age and BMI had modifying effects on these associations.
Bisphenol A (BPA) as an endocrine disrupting chemical has been shown to alter reproductive endocrine function, but little is known on its analogues such as bisphenol F (BPF) and bisphenol S (BPS) with increasing usage and exposure.
To explore the associations between exposures to BPA, BPF and BPS and serum reproductive hormones among reproductive-aged Chinese men.
We measured BPA, BPF and BPS concentrations in repeated urine samples and multiple reproductive hormones in the serum samples collected from 462 men attending an infertility clinic in Wuhan, China. Linear regression models were applied to assess the associations between averaged urinary BPA, BPF and BPS levels and serum hormone concentrations, and restricted cubic spline (RCS) models were further utilized to explore potential non-linear associations. We also examined potential modifying effects by age and body mass index (BMI).
There was little evidence of associations between BPA exposure and altered reproductive hormones. However, we found that elevated BPF and BPS exposures were in negative associations with estrogen (E2) levels and E2/T (total testosterone) ratio (all P for trends < 0.05), and that elevated BPS exposure was negatively associated with SHBG levels (P for trend = 0.09). Based on the RCS models, these linear negative associations except that between BPS exposure and E2/T ratio were further confirmed. In stratified analyses, BPF and BPS exposures in relation to reduced E2 and E2/T ratio were more pronounced among men aged > 30 years, whereas their associations with reduced SHBG levels were more pronounced among men aged ≤ 30. Also, BPS exposure in negative association with FSH only emerged among men with BMI ≥ 24 kg/m2 (P for interaction = 0.03).
BPF and BPS exposures were negatively associated with male serum E2, E2/T ratio and SHBG levels, and these associations varied by age and BMI.
A simply and sensitively electroanalytical method for determination of bisphenol A (BPA) using poly(amidoamine) (PAMAM) and Fe sub(3)O sub(4) magnetic nanoparticles modified glassy carbon electrode ...(GCE) was presented. Compared with bare electrode, PAMAM-Fe sub(3)O sub(4) modified electrode not only significantly enhanced the oxidation peak current of BPA, but also lowered the oxidation overpotential, suggesting that the modified electrode can remarkably improve the determining sensitivity of BPA. Factors influencing the detection processes were optimised and kinetic parameters were calculated. Under the optimal conditions, the oxidation current increased linearly with increasing the concentration of BPA in the range of 1 x 10 super(-8)-3.07 x 10 super(-6) M with the correlation coefficient of 0.9996 and the detection limit of 5 x 10 super(-9) M. The current reached 95% of the steady-state current within about 6 s. The proposed method was successfully applied to determine BPA in milk samples and satisfactory results were obtained.
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