Xiaohong Lin

The heavy metal content of particulate matter was investigated in the city of Guangzhou in southern China. Samples of urban foliage near 36 pedestrian bridges were analyzed to determine their Zn, Pb, Cu, Cr, V, Ni, and Co contents after digestion in a mixture of strong acids composed of HNO3, HCl, HF, and HClO4. The results revealed a severe heavy metal pollution compared with the background levels in Chinese soils, except for Co and V. The mean concentrations of Zn (1,024 mg kg−1), Pb (233 mg kg−1), Cu (203 mg kg−1), Cr (118 mg kg−1), V (41.9 mg kg−1), Ni (41.4 mg kg−1), and Co (11.3 mg kg−1) in urban dust were higher than the reference levels, and were highest in samples located near high-traffic areas. Multivariate statistical methods (correlation analysis, principal-components analysis, and clustering analysis) were used to identify the possible sources of the metals. Three main pollutant sources are assigned: Zn, Cu and Ni levels were strongly correlated and were possibly related to combustion processes and vehicles; Pb, Cr and Co were mainly derived from traffic sources, combined with soil sources; and V mainly originated from natural sources.

For deceptive jamming against Synthetic Aperture Radar (SAR), generating jamming signal of large scene is difficult, due to its huge computation. However, it is acceptable to generate jamming signal in real-time but in low precision. Based on inverse Range Doppler algorithm (IRDA), a realtime deceptive jamming method for large scene is proposed in this paper. An analysis of the degradation of jamming image caused by an approximation in the method is done. Simulation results verify the rationality of the approximation and the effectiveness of this method.

BACKGROUND: Human papillomavirus (HPV) is the leading cause of cervical cancer with more than 200 genotypes. Different genotypes have different potentials in causing premalignant lesions and cervical cancers. In this study, we investigated the age-specific prevalence and genotype distribution of HPV genotypes in Northwest China. MATERIALS AND METHODS: We recruited 145,918 unvaccinated women from Northwest China for population-based HPV DNA screening test during June 2015 to December 2020. And a lab-based test was performed for each volunteer by flow fluorescent technology to identify the genotypes of HPV. RESULTS: The overall infection rate of HPV was 22.97%. With the participants divided into 12 groups according to age, a bimodal curve of infection rate was obtained. And the two peaks appeared in the younger than 20 group and 61-65 group, respectively. The five most common HPV genotypes included HPV 16, 58, 52, 53 and 61 in all participants, which were in descending order of frequency. Among women younger than 25 years old, HPV 6 and 11 were more common and even higher than some genotypes mentioned above. Among women older than 65 years old, HPV 18 and 66 were more common than or as high as the six most common genotypes in all populations. Additionally, the distribution of single and multiple infections in each age group was also different. CONCLUSION: The baseline prevalence and genotype distribution of HPV in Northwest China was uncovered for the first time. Age was related to the epidemiology of different HPV genotypes. All the results would be of great significance for future healthcare services.

Based on the typhoon track and intensity data and the precipitation data of typhoon in China during 1961–2020, the overall characteristics of the rainstorm in Fujian caused by typhoon passing though Taiwan Island were studied. More than 80 percent of typhoons passing though the Taiwan Island can bring heavy rain to Fujian. There are 1.5 events of typhoon rainstorm in Fujian every year, and the average annual impact days are 3.0. In terms of spatial distribution, the frequency and intensity of cross-island typhoon rainstorm decrease rapidly from the coastal areas of Fujian to the inland areas, and Zherong, Changle and Jiu xianshan stations in the coastal areas are the high value centers. The typhoon paths of cross-island typhoon rainstorm in Fujian are mainly divided into three categories: landing-Fujian type (including landing-Fujian northeast turning, landing-Fujian middle northbound and landing-Fujian south westbound), landing-Guangdong and Zhejiang type and offshore turning type, among which landing-Fujian type typhoon has the most significant influence(only the landing-Fujian type appears the rainstorm of ≥50 mm·(24 h)−1), and the rainstorm intensity, influence range and asymmetrical structure of the rainstorm are the strongest, the most extensive and the most significant in the landing-Fujian middle northbound path. Based on the NCEP reanalysis data, the comparative analysis of the environmental fields causing the difference of precipitation intensity between the two typhoons landing-Fujian middle northbound and landing-Fujian south westbound shows that: To the landing-Fujian middle northbound track, strong wind speed area on the north side of the typhoon center leads to strong onshore winds, in the role of mountain terrain, piedmont has better convergence and very strong deep vertical upward movement, with better moisture conditions, it can send low high-energy water vapor to the middle, the precipitation dynamics and water vapor conditions are significantly stronger than the landing-Fujian south westbound track, resulting in more typhoon heavy rain.