Effects of 1.8 GHz radiofrequency field on microstructure and bone metabolism of femur in mice.

To investigate the effects of 1.8 GHz radiofrequency (RF) field on bone microstructure and metabolism of femur in mice, C57BL/6 mice (male, age 4 weeks) were whole-body exposed or sham exposed to 1.8 GHz RF field. Specific absorption rates of whole body and bone were approximately 2.70 and 1.14 W/kg (6 h/day for 28 days). After exposure, microstructure and morphology of femur were observed by microcomputed tomography (micro-CT), Hematoxylin and Eosin (HE) and Masson staining. Subsequently, bone parameters were calculated directly from the reconstructed images, including structure model index, bone mineral density, trabecular bone volume/total volume, connectivity density, trabecular number, trabecular thickness, and trabecular separation. Biomarkers that reflect bone metabolism, such as serum total alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase 5b (TRACP-5b), were determined by biochemical assay methods. Micro-CT and histology results showed that there was no significant change in bone microstructure and the above parameters in RF group, compared with sham group. The activity of serum ALP and BALP increased 29.47% and 16.82%, respectively, in RF group, compared with sham group (P < 0.05). In addition, there were no significant differences in the activity of serum TRACP-5b between RF group and sham group. In brief, under present experimental conditions, we did not find support for an effect of 1.8 GHz RF field on bone microstructure; however, it might promote metabolic function of osteoblasts in mice. Bioelectromagnetics. 39:386-393, 2018. © 2018 Wiley Periodicals, Inc.

[Characteristics of Atmospheric Dry and Wet Deposition of Trace Metals in the Hinterland of the Three Gorges Reservoir, China].

In order to investigate the characteristics of atmospheric trace metals deposition in the hinterland of the Three Gorges Reservoir, the wet and dry deposition samples were collected at an urban area sampling site in Wanzhou during January to June 2014. Besides, the samples were collected at five other sampling sites in April 2014 for comparative analysis, including factory region, town suburb, nature reserve, county suburb, and rural area. pH, conductivity, and trace metals (Al, As, B, Ba, Bi, Cd, Co, Cr, Cu, Fe, Li, Mn, Pb, Ni, Sb, Sr, Sn, Ti, Zn, V) were analyzed. In urban area, the acid rain frequency was 48.44% , and the acid rain occurred mainly in the period of January to April. The order of acid rain frequency in various functional areas was factory region > urban area > county suburb > town suburb > nature reserve > county rural area. All of the trace metals in wet deposition during the sampling period were lower than the National Environmental Quality Standard for Surface Water Standard of Class III. Cd, Cu, Ph and Zn were found exceeding the standard of class I , and the pollution in factory region was more serious compared to other functional areas. The extract pH of dry deposition in urban area was in the range of 4.91-6.74, with an average value of 5.79. The order of dry deposition in various functional areas was factory region > county suburb > urban area > county rural area > town suburb > nature reserve, which was exactly the same as that of the wet deposition, indicating the similar sources of dry and wet deposition. In urban area, the contents of Ba, Co, Cu, Cr, Li, Mn, Ni, Sr, Zn in dry deposition were greater than those in wet deposition, but the contents of Al, As, B, Bi, Cd, Fe, Ph, Sb, Sn, Ti, V showed the opposite trend. Analysis of the enrichment factors showed that Al was in moderate enrichment, while Bi and Cd were significantly enriched.

[Seasonal Variation and Source Analysis of the Water-soluble Inorganic Ions in Fine Particulate Matter in Suzhou].

A total of 87 daily PM2.5 samples were collected in the urban area of Suzhou city during 2015, representing spring, summer, autumn, winter, respectively. Mass concentration of PM2.5 was analyzed gravimetrically. Water-soluble inorganic ions, including F-, Cl-, NO3-, SO42-, Na+, NH4+, K+, Mg2+and Ca2+, were determined by ion chromatography. The average mass concentration of PM2.5 was (74.26±38.01) µg·m-3. The seasonal variations of PM2.5 concentrations decreased in the order of winter > spring > autumn > summer. The average total mass concentrations of 9 ions was (43.95±23.60) µg·m-3, and the order of concentration of ions was NO3- > SO42- > NH4+ > Na+ > Cl- > K+ > Ca2+ > F- > Mg2+. Seasonal variation of ion concentrations was significant, with the highest concentration observed in winter and the lowest in summer. The secondary inorganic species, including SO42-, NO3- and NH4+ (SNA) were the major components of the water-soluble ions in PM2.5. SNA's correlations with each other were significant. SO42-, NO3- and NH4+ were probably in the form of NH4NO3 and (NH4)2SO4. The [NO3-]/[SO42-] ratio approaching to 1 implied that mobile sources were as important as stationary sources. Ion balance calculations indicated strong correlations between anion and cation equivalents. The PM2.5 was acidic. Industrial emission, combustion process, secondary formation and fugitive dust were the major sources of the water-soluble ions in PM2.5..

Mechanisms of interaction between polycyclic aromatic hydrocarbons and dissolved organic matters.

Binding of phenanthrene and fluorene to a number of humic and fulvic substances isolated from various sources as well as a commercially available humic acid, was investigated using a fluorescence quenching approach. The observed fluorescence quenching indicated by linear Stern-Volmer plots and high bimolecular quenching rate constant was induced by a static interaction process. A significant correlation of binding constants with aromaticity and polarity of dissolved organic matter (DOM) was observed. It is hypothesized that the binding of polycyclic aromatic hydrocarbons (PAHs) by DOM is due to both π-π interactions and hydrophobic interactions. In addition, energy transfer from PAHs to DOM occurs because of the significant overlap between the absorbance spectra of DOM and emission spectra of PAHs. Thus, dipole-dipole interaction may also play an important role in the binding mechanism between PAHs and DOM.

[Analysis of three-dimensional fluorescence overlapping spectra using differential spectra and independent component analysis].

The analysis of multi-component three-dimensional fluorescence overlapping spectra is always very difficult. In view of the advantage of differential spectra and based on the calculation principle of two-dimensional differential spectra, the three-dimensional fluorescence spectra with both excitation and emission spectra is fully utilized. Firstly, the excitation differential spectra and emission differential spectra are respectively computed after unfolding the three-dimensional fluorescence spectra. Then the excitation differential spectra and emission differential spectra of the single component are obtained by analyzing the multicomponent differential spectra using independent component analysis. In this process, the use of cubic spline increases the data points of excitation spectra, and the roughness penalty smoothing reduces the noise of emission spectra which is beneficial for the computation of differential spectra. The similarity indices between the standard spectra and recovered spectra show that independent component analysis based on differential spectra is more suitable for the component recognition of three-dimensional fluorescence overlapping spectra.

Hydrothermal synthetic mercaptopropionic acid stabled CdTe quantum dots as fluorescent probes for detection of Ag⁺.

Mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs) with particle size 3 nm have been successfully synthesized in aqueous medium by hydrothermal synthesis method. And the effects of different metal ions on MPA capped CdTe QDs fluorescence were studied using fluorescence spectrometry. The results demonstrated that at the same concentration level, Ag(+) could strongly quench CdTe QDs fluorescence, and the other metal ions had little effect on CdTe QDs fluorescence except Cu(2+). On the basis of this fact, a rapid, simple, highly sensitive and selective method based on fluorescence quenching principle for Ag(+) detection in aqueous solution was proposed. Under optimal conditions, the quenched fluorescence intensity (F(0)-F) increased linearly with the concentration of Ag(+) ranging from 4 × 10(-7) to 32 × 10(-7)mol L(-1). The limit of detection for Ag(+) was 4.106 × 10(-8)mol L(-1). The obtained plot of F(0)/F versus [Ag(+)] was an upward curvature, concave towards the y-axis, rather than a straight line. The modified form of the Stern-Volmer equation was third order in Ag(+) concentration. According to the modified Stern-Volmer equation, it can be inferred that dynamic quenching and static quenching simultaneously occurred when Ag(+) interacted with MPA capped CdTe QDs. At the same time other factors might also influence the quenching process. Based on this study, hydrothermal synthesized MPA capped CdTe QDs with particle size 3 nm may be used as a novel fluorescence probe to quantificationally and selectively detect Ag(+).

Application of excitation-emission matrix fluorescence combined with second-order calibration algorithm for the determination of five polycyclic aromatic hydrocarbons simultaneously in drinking.

Direct determination of five polycyclic aromatic hydrocarbons including fluorene, anthracene, phenanthrene, pyrene and fluoranthene was accomplished by excitation-emission matrix fluorescence coupled with chemometric methods based on an alternating trilinear decomposition (ATLD) algorithm. A uniform design and orthogonal design are proposed for the creation of the calibration set. Results showed that no significant difference in the recoveries for each of the PAHs was observed. Thus, both of the designs can be used for the calibration set. In addition, some statistical parameters and figures of merit, such as average recovery, root-mean-square error of prediction, sensitivity, and selectivity were investigated to evalute the performance of the proposed method. The results showed that fluoranthene was the most selective, whereas fluorene was more sensitive than any other compound. This method was also employed for the determination of samples of drinking water spiked with all these PAHs. It can be observed that the results were not as satisfying as those in synthetic samples due to the negative effects of humic acid or fulvic acid in drinking water.

[Excitation-emission fluorescence characterization study of the three phenolic compounds].

The fluorescence intensity information was collected by scanning its fluorescence spectra at different excitation wavelengths. Based on its high sensitivity and selectivity, excitation-emission fluorescence can be widely used for detection of pollutants in the environment. The characterizations of the three phenolic compounds were investigated by this method, and the fluorescence peaks of phenol, m-cresol and thymol were confirmed at 272/300 nm, 274/300 nm and 276/304 nm when the excitation and emission wavelength were set in the range of 240-360 nm and 260-500 nm respectively. The excitation and emission spectra of the three phenolic compounds are very similar because of their analogical structure. The intensity of the spectrum has a good linear relationship with the concentration when the solution concentration is between 0.02 and 1.0 mg x L(-1), and the limits of detection can reach at 1 microg x L(-1). Results show that the three compounds can be analyzed qualitatively and quantitatively by excitation-emission fluorescence.