OBJECTIVETo investigate the permance index ofof portable X-ray fluorescence spectrometer in the determination of lead on filter membrane and to provide data for the determination of lead in workplace air.

METHODSIrradiated with X-ray, the lead would emit specific X-ray fluorescence during the process from the excited state back to the ground state. Rapid determination of lead was completed using fluorescence energy and wave length for qualitative analysis and fluorescence intensity for quantitative measurement. Under set conditions, a series of customized calibration samples were measured to create a standard curve for quantitative analysis of lead on filter membrane.

RESULTSThe regression equation obtained using a portable X-ray fluorescence spectrometer to determine the lead on filter membrane was y=0.004x-0.182 (r2= 0.9999). The linear range was 0.00 -10.40 mg/m3, the minimum detectable concentration was 0.53 µg/m3, and the minimum quantifiable concentration was 1.76µg/m3. The relative standard deviation (RSD) of within-run precision of samples with different concentrations was 0.48%-6.22%, the RSD of between-run precision was 2.51%-5.09%, and the degree of accuracy was in the calibration range of standard samples.

CONCLUSIONPortable X-ray fluorescence spectrometry is a simple, rapid, repeatable, and accurate method for the determination of lead on filter membrane.

Air Pollutants, Occupational ; analysis ; Lead ; analysis ; Spectrometry, X-Ray Emission ; Workplace

Objective To investigate the effect of SP600125 on the proliferation, cell cycle, apoptosis and invasion of human cervical cancer HeLa cells. Methods CCK-8 method was used to detect the proliferation of HeLa cells treated with different concentrations of SP600125 at different time points. The 20 μmol/L of SP600125 was determined for subsequent experiments. Cell proliferation ability was detected using plate clone formation assay; nuclear morphology was observed by DAPI staining; cell cycle and apoptosis were measured by flow cytometry; cell migration and invasion were detected by cell scratch and Transwell methods; the mRNA and protein levels of p53, Mad2L1 and CDC20 were measured by qRT-PCR and Western blot after SP600125 treatment at different time points. Results Compared with control group (0.1%DMSO), cells proliferative activity were reduced by 10, 20, 30, 40 and 50 μmol/L SP600125 treatment for 24h. Compared with control group, the rate of apoptosis was significantly increased in SP600125 treatment groups, and the cell proportion in G₂/M phase increased (P < 0.001), while the cell proportion in G₀/G₁ phases cells was reduced after SP600125 treatment for 24h and 48h (P < 0.001), and the clonal number, migration and invasion ability of HeLa cells also decreased significantly (P < 0.001). qRT-PCR and Western blot results showed a significant decrease in Mad2L1 mRNA and protein expression (P < 0.05) and a significant increase in p53 and CDC20 mRNA and protein expression (P < 0.01). Conclusion SP600125 can induce cell cycle arrest of cervical cancer HeLa cells in G₂/M phase by upregulating p53 and CDC20 and downregulating Mad2L1 expression, and promote cell apoptosis to inhibit cell proliferation, migration and invasion.

Objective: To explore the relationship between lifestyle and myopia and depressive symptoms comorbidity among primary and secondary school students in Nanjing, so as to provide a scientific basis for developing effective prevention measures. Methods: In October 2022, a stratified cluster random sampling method was used to select primary and secondary school students aged 9-19 years in 4 urban and 4 suburban districts in Nanjing as the research subjects. A total of 10 498 students were included for physical examination and questionnaire survey by using the student health condition and influencing factors questionnaire. Chisquare test was used for univariate analysis, and multifactor Logistic regression analysis was used to analyze the relationship between students lifestyle and the cooccurrence of myopia and depressive symptoms. Results: The prevalence of comorbidity of screening positive myopia and depression among primary and secondary school students in Nanjing was 18.11%. The prevalence of comorbidity was higher in girls (20.97%) than in boys (15.47%), higher in boarding students (31.31%) than in nonboarding students (16.51%), and higher in high school students than in middle and primary school students (28.63%, 19.10%, 7.76%), with statistically significant differences (χ2=53.49, 149.31, 522.55, P<0.01). Multivariate Logistic regression results showed that smoking (OR=1.51), drinking (OR=2.36), looking at electronic screens in dim conditions (OR=2.40), screen time ≥2 h/d(OR=1.50), afterschool homework time ≥2 h/d(OR=1.48) were positively correlated with the prevalence of comorbidity of screening positive myopia and depressive symptoms, healthy diet (OR=0.67), outdoor activities during breaks (OR=0.80), sufficient sleep (OR=0.64), meeting physical activity standards (OR=0.74) and outdoor activity time ≥2 h/d(OR=0.84) were negatively correlated with the prevalence of comorbidity of screening positive of myopia and depressive symptoms (P<0.05). Conclusions The lifestyle of primary and secondary school students in Nanjing is related to the comorbidity of myopia and depressive symptoms. Schools and families should carry out relevant education and intervention measures to promote students to develop good living habits and jointly prevent the occurrence of myopia and depressive symptoms.

To improve the yield of sucrose isomerase from Pantoea dispersa UQ68J, we studied the effect of different signal peptides and fermentation conditions on sucrose isomerase expression in Escherichia coli. The gene of sucrose isomerase was optimized and expressed in E. coli BL21 (DE3) with native signal peptide which was named as ORI strain. The total and extracellular enzyme activity was 85 and 65 U/mL in the flask, respectively. The mature protein, which started from the 22th amino acid, was connected with the PelB and OmpA signal peptide to construct P22 and O22 strain, respectively. The total activity of P22 reached 138 U/mL, which was 1.6 times of ORI strain. The total activity of O22 strain was similar to that of ORI strain. Induced by 3.0 g/L lactose, the total activity of P22 strain increased to 168 U/mL. In 3 L fermentor, the effects of glycine concentration and induction time were studied. Induction when the DCW reached 18 g/L (OD₆₀₀=30), with 0.5% glycine, the extracellular enzyme activity reached 1 981 U/mL, and the total enzyme activity reached 2 640 U/mL, which is the highest activity of sucrose isomerase that was expressed in recombinant E. coli.
Bacterial Proteins ; biosynthesis ; Bioreactors ; Escherichia coli ; metabolism ; Fermentation ; Gene Expression ; Glucosyltransferases ; biosynthesis ; Lactose ; Pantoea ; enzymology ; Protein Sorting Signals ; Recombinant Proteins ; biosynthesis

Objective To explore the biological mechanisms of electroacupuncture (EA) for depression. Methods Forty male adult Sprague-Dawley rats were randomly divided into control group (n=8), model group (n=8), EA group (n=8) and fluoxetine group (n=8). Depressive models were established with lonely raising and chronic unpredictable mild stress. They were tested with Open-field Test, and the expression of phosphodiesterase 4 (PDE4)A and PDE4D in hippocampus was detected with RT-PCR. Results The cross and rear scores were significantly lower in the model group than in the control group (P<0.001), while it increased in the EA group and the fluoxetine group (P<0.001). Compared with the model group, the expression of PDE4A and PDE4D decreased in the EA group (P<0.001). Conclusion Electroacupuncture may relieve depression through inhibiting the expression of PDE4A and PDE4D.