There are many noise signals in original laser induced breakdown spectroscopy (LIBS) spectra.To explore the effect of spectral pretreatment on LIBS information by different filter methods, the LIBS spectra of Pb-polluted cabbage in wavelength range of 400.45-410.98 nm was investigated and preprocessed by adjacent averaging, Savitzky-Golay (S-G) and fast Fourier transformation (FFT).Then partial least square (PLS) model was established for evaluating the spectral treatment effect.The result showed that the root mean square error of prediction (RMSEP) and average relative error of S-G method were 0.26 and 3.7%, suggesting a superior smoothing effect than other methods.Experimental results indicated that an appropriate filtering method could help to improve the spectral quality and raise the precision of model checkout.

Endemic arsenicosis is a kind of endemic diseases, which is caused by chronic arsenic exposure and is seriously harmful to human health. Skin is the important target organ of endemic arsenicosis. Clinical diagnosis for this endemic disease mainly depends on the cutaneous triad (hyperkeratosis on the palms and soles, cutaneous hyper-pigmentation and hypo-pigmentation).But the pathogenesis of this disease is still unclear.In-depth understanding of the skin lesions and the pathogenesis is greatly significant for the scientific explanation of endemic arsenicosis. Although there are some studies on the skin lesions caused by endemic arsenicosis, a systematic review is still lacking. In this paper, the epidemiology, pathological changes and pathogenesis of skin lesions caused by endemic arsenicosis are summarized. Here we expect this summarization will deepen the understanding on skin lesions caused by endemic arsenicosis and provide some new ideas and clues for other researchers.

Keratinocytes are the main constituent cells of the skin epidermis and the main target cells of arsenic act on the skin as well.Although it has been epidemiologically clarified that arsenic can cause palmoplantar hyperkeratosis and skin cancer,yet the mechanism is unclear and there's no ideal animal models so far.Currently,the studies of skin lesions induced by arsenic mainly focus on keratinocytes in vitro.In this paper,we summarize the related literatures and review the effects of arsenic on proliferation,differentiation,oxidative stress,DNA damage,apoptosis,epigenetic changes,and cancer stem cell activation of keratinocytes.We hope to deepen the understanding of skin lesions induced by arsenic and provide more basis and ideas for understanding the mechanism of endemic aRSenicosis.

Objective:To explore whether autophagy is involved in dysfunction of vascular endothelial induced by sodium arsenite (NaAsO 2). Methods:Human primary umbilical vein endothelial cells were isolated and cultured. The cells were treated with different levels of NaAsO 2 [0 (control)), 2, 5, 10, 20, 30, 50 μmol/L] for 24 h, and cell viability was determined using CCK8. According to the results of CCK8, the levels of arsenite used in subsequent experiments were determined, intracellular nitric oxide (NO) content (incubated by NaAsO 2 for 4 h) was detected by flow cytometry, LC3 levels (incubated by NaAsO 2 for 0, 6, 12 and 24 h) was detected using Western blotting, and autophagosome (incubated by NaAsO 2 for 12 h) was observed by electron microscope. At the same time, human primary umbilical vein endothelial cells were pretreated with 0.1 mmol/L 3-MA (autophagy inhibitor) for 2 h, and induced by 30 μmol/L NaAsO 2, and the above detection indicators were compared with those of the 30 μmol/L NaAsO 2 group. Results:Human primary umbilical vein endothelial cells were successfully isolated and cultured. Compared with the control group [cell viability: (99.97 ± 5.33)%, NO content: 42 048.34 ± 789.61], the cell viability [(73.00 ± 0.86)%] and NO content (23 353.97 ± 971.85) of 30 μmol/L NaAsO 2 group were remarkably lower, and the differences were statistically significant ( P < 0.01). Incubated with 30 μmol/L NaAsO 2 at different time points 6, 12, 24 h, LC3Ⅱ levels (5.782 ± 2.789, 9.692 ± 2.222, 5.573 ± 2.941) were significantly elevated than those of control group (1.000 ± 0.383, P < 0.05), and the LC3 Ⅱ level was the highest at 12 h. After treatment with 30 μmol/L NaAsO 2 for 12 h, the number of autophagosome in cells observed under electron microscope was significantly higher than that of the control group. Compared with 30 μmol/L NaAsO 2 group [cell viability: (68.78 ± 1.55)%, LC3 Ⅱ level: 5.680 ± 0.545, NO content: 13 025.78 ± 962.61], cell viability [ (79.54 ± 4.99) %] in 3-MA+ NaAsO 2 group was increased, the LC3Ⅱ level (3.956 ± 0.398) was decreased, and the differences were statistically significant ( P < 0.05); intracellular NO content (13 988.51 ± 1 671.07) increased, whereas the difference was not statistically significant ( P > 0.05). Conclusion:Autophagy is involved in the vascular endothelial dysfunction induced by arsenic.

Objective:To establish a method for preparing urine arsenic quality control samples and verify its uniformity and stability.Methods:Urine samples of healthy adults were collected, concentrated and then freeze-dried using a freeze dryer. The freeze-dried samples were subjected to atomic fluorescence spectrophotometry to determine the arsenic content. The method was verified from the uniformity, stability, determination of different detection methods, and the fixed value of urine arsenic content.Results:The linear correlation coefficient of the standard curve of the method was 0.999 7. The variation coefficients of arsenic content after freeze-dried of urine samples were all < 5%. The uniformity test results showed that there was no statistically significant difference in the arsenic content between bottles of low and high concentration samples ( t = 1.09, 1.53, P > 0.05), and the sample uniformity was good. The stability test results show that the decline rate of the freeze-dried samples of high and low concentrations stored ≤360 days was less than 10%, and the stability was good at room temperature. Atomic fluorescence spectrophotometry and inductively coupled plasma mass spectrometry(ICP-MS) were used for the arsenic content determination of high and low concentration samples, and there was no significant difference between the two methods ( P > 0.05). The results of determination of arsenic content in urine of 14 provinces and 86 cities and counties showed that the low concentration was (0.028 ± 0.002) mg/L and the high concentration was (0.113 ± 0.008) mg/L. Conclusion:The uniformity and stability of the freeze-dried urine arsenic quality control samples can meet the external quality control requirements of the laboratory in endemic disease prevention and monitoring.