In this work, reduced graphene oxide coated with ZnO (RGO-ZnO) nanocomposites was synthesized by a hydrothermal reduction strategy. The presence of ZnO was characterized by Fourier transform infrared spectroscopy (FT-...
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In this work, reduced graphene oxide coated with ZnO (RGO-ZnO) nanocomposites was synthesized by a hydrothermal reduction strategy. The presence of ZnO was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Subsequently, RGO-ZnO was used as a dispersive solid-phase extraction (DSPE) sorbent for the enrichment of eight organophosphorus pesticides (OPs) in apple, cucumber and water samples prior to their determination by gas chromatography-mass spectrometry (GC-MS). Several experimental parameters affecting the extraction efficiencies, including the amount of RGO-ZnO, extraction time, and the pH of the sample solution, as well as the type and volume of eluent solvent, were investigated and optimized in this work. Under the optimal experimental conditions, good linearity existed in the range of 0.5-200.0 ng g(-1) for all the analytes with the correlation coefficients (R-2) ranging from 0.9894 to 0.9983. The limits of detection (S/N = 3) of the method for the compounds were between 0.01 and 0.05 ng g(-1). Good reproducibilities were acquired with the relative standard deviations (RSDs) below 8.6% for both intra-day and inter-day precision. The recoveries of the method were in the range of 75.0% to 104.2%.
The measurement of volume pulse waves may be easily affected based on the measured position (different fingers or toes), body posture, as well as other factors. Therefore, interferences during measurement need to be r...
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The measurement of volume pulse waves may be easily affected based on the measured position (different fingers or toes), body posture, as well as other factors. Therefore, interferences during measurement need to be removed. For this study, relevant parameters of volume pulse wave were obtained by changing the affecting factors. The data were analyzed in order to indicate the differences in volume pulse wave parameters among different fingers and toes in four postures. Results showed that when subjects were lying, inclined or in a sitting posture, volume pulse wave parameters of the index finger, middle finger and ring finger on both hands displayed no apparent differences. When subjects were in a sitting posture, volume pulse wave parameters of the big, second and third toes on both feet showed no significant differences.
Thallium (Tl) is a trace metal of severe toxicity. Its health concerns via consumption of contaminated vegetables have often been overlooked or underestimated. This study was designed to gain insight into the actual l...
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Thallium (Tl) is a trace metal of severe toxicity. Its health concerns via consumption of contaminated vegetables have often been overlooked or underestimated. This study was designed to gain insight into the actual level and distribution characteristics of Tl and metal (loid)s (Pb, Cd, Cr, Sb, Mn, Cu, Zn, Ni, and Co) in agricultural soils and common vegetables cultivated in different zones (upstream, midstream, and downstream) of a densely populated residential area in a typical mine city, which has been open-pit exploiting Tl-bearing pyrite minerals since 1960s. The results show that most of the agricultural soils exhibit contaminated levels of Tl, with Tl contents (upstream: 1.35-4.31 mg/kg, midstream: 2.43 -5.19 mg/kg, and downstream: 0.65-233 mg/kg) mostly exceeding the maximum permissible level (MPL) for agricultural land use (1 mg/kg). Sequential extraction procedure indicates that even Tl is predominantly retained in the residual fraction, significant levels of Tl are still present in the geochemically mobile fractions. Besides, metals like Cu, Cd, Mn, and Co are mostly distributed in the labile fractions. Almost all metal (loid)s in edible parts of the vegetables exceed their corresponding MPL for consumption. The chronic daily intake (CDI) and hazard quotient (HQ) values calculated for inhabitants at different ages indicate non-negligible Tl risks via consumption of local vegetables, especially for children. Therefore, it is critical to establish effective measures for hazardous waste management and enforceable regulations in Tl-polluted area to mitigate potential severe impacts of Tl on human health through food chain. (C) 2019 Elsevier Ltd. All rights reserved.
BACKGROUND: Gestational diabetes mellitus (GDM) is not easily detected. The difficulty in detecting GDM is largely due to the late onset of clinical symptoms as well as the various complications that result from GDM [...
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BACKGROUND: Gestational diabetes mellitus (GDM) is not easily detected. The difficulty in detecting GDM is largely due to the late onset of clinical symptoms as well as the various complications that result from GDM [1]. OBJECTIVE: GDM greatly influences both mother and child. Therefore, the purpose of this study was to reduce the morbidity of GDM. METHODS: In this study, risk factors that influence GDM were selected through statistical analysis. Multivariable logistic regression analysis was used to obtain the regression equation and Odds Ratio (OR) value. The risk score of each factor was obtained according to the OR value. RESULTS: The score of every pregnant woman could be very intuitively used to show the risk of getting GDM. CONCLUSION: Through the above methods, a comprehensive risk evaluation method of detecting GDM was developed.
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