Spatial patterns and the associated factors for breast cancer hospitalization in the rural population of Fujian Province, China.

BACKGROUND: Despite the known increasing incidence of breast cancer in China, evidence on the spatial pattern of hospitalization for breast cancer is scarce. This study aimed to describe the disparity of breast cancer hospitalization in the rural population of Southeast China and to explore the impacts of socioeconomic factors and heavy metal pollution in soil. METHODS: This study was conducted using the New Rural Cooperative Medical Scheme (NRCMS) claims data covering 20.9 million rural residents from 73 counties in Southeast China during 2015-2016. The associations between breast cancer hospitalization and socioeconomic factors and soil heavy metal pollutants were evaluated with quasi-Poisson regression models and geographically weighted Poisson regressions (GWPR). RESULTS: The annual hospitalization rate for breast cancer was 101.40/100,000 in the studied area and the rate varied across different counties. Overall, hospitalization for breast cancer was associated with road density (ß = 0.43, P = 0.02), urbanization (ß = 0.02, P = 0.002) and soil cadmium (Cd) pollution (ß = 0.01, P = 0.02). In the GWPR model, a stronger spatial association of Cd, road density and breast cancer hospitalization was found in the northeast regions of the study area while breast cancer hospitalization was mainly related to urbanization in the western regions. CONCLUSIONS: Soil Cd pollution, road density, and urbanization were associated with breast cancer hospitalization in different regions. Findings in this study might provide valuable information for healthcare policies and intervention strategies for breast cancer.

Inferior alveolar canal segmentation based on cone-beam computed tomography.

PURPOSE: The shape and position of the inferior alveolar canal (IAC) are analyzed to effectively reduce the risk of iatrogenic injury based on cone-beam computer tomography (CBCT). To assist dental clinicians to make better use of the IAC information, we propose an IAC segmentation method based on CBCT images. METHODS: In this paper, CBCT images are first preprocessed by the Hounsfield unit values clipping and gray normalization. Secondly, based on the multi-plane reconstruction (MPR) and curved surface reconstruction, the curved MPR image sets are generated by the smooth dental arch curve with a sampling distance of 1.00 pixels. Then, the K-means clustering algorithm is used to cluster the texture parameters of the gray level-gradient co-occurrence matrix enhanced by the gradient directions to improve the image contrast of the IAC. Finally, the IAC edges are roughly segmented by the 2D line-tracking method, and smoothed by the fourth-order polynomial to obtain the final segmentation result. RESULTS: Twenty-one real clinical dental CBCT datasets were used to test the proposed method. The manual segmentation results of two specialized dental clinicians were used as quantitative evaluation criteria. The dice similarity index (DSI), average symmetric surface distance (ASSD), and mean curve distance (MCD) of the left IAC are 0.93 (SD = 0.01), 0.16 mm (SD = 0.05 mm), and 1.59 mm (SD = 0.25 mm), respectively; the DSI, ASSD, and MCD of the right IAC are 0.93 (SD = 0.02), 0.16 mm (SD = 0.05 mm), and 1.60 mm (SD = 0.30 mm), respectively. CONCLUSIONS: The proposed method provides an effective image enhancement and segmentation solution to analyze the shape and position of the IAC. Experimental results show that the relationships between the IAC and other structures can be accurately reflected in the panoramic images without superimposition and geometric distortion, and the smooth edges of the IAC can be segmented.

Spatial and temporal variations of land use and vegetation cover in Southwest China from 2000 to 2015.

Southwestern China is an important ecologically resource area and ecologically fragile area in China, which plays an important role in the national project of "Clear Waters and Green Mountains". Based on land use data set with a 1 km spatial resolution and combined with land use transfer matrix, we analyzed the characteristics and driving forces of land use change in Southwest China from 2000 to 2015. Based on the MODIS remote sensing index, we calculated the vegetation coverage in Southwest China using the dimidiate pixel model, and analyzed the changes of the normalized vegetation index (NDVI) and vegetation coverage. Results showed that the main land types were woodland, cropland and grassland. The built-up land area increased by 5874 km2(55.8%), the cropland area decreased by 6211 km2, and grassland decreased by 2099 km2. From 2000 to 2015, the area that had been changed to built-up land was the largest, mainly from cropland (contributed 68.2%), woodland (contributed 19.2%) and grassland (contributed 13.1%). The transformed areas were mostly close to urban area. The area and rate for the transformation of cropland were 7079 km2 and 2.2% respectively, accounting for 46.0% of all the transferred out areas. Most of the woodland were transformed from grassland (61.8%), mainly distributed in central and southern Guizhou and western Yunnan. Both NDVI and vegetation coverage were significantly increased, indicating that the whole region was greening. NDVI of both natural vegetation and cropland increased significantly, while the NDVI of areas with expanded build-up land decreased. Therefore, natural vegetation and cropland dominated the vegetation change in this region. Results of the resi-dual analysis showed that both climate change and human activities contributed significantly to the greening trend.

Reconstruction of cropland cover changes in the Shandong Province over the past 300 years.

To advance global change research, it is essential to reconstruct changes in historical cropland coverage on a regional scale in China. This paper presents data collected from 244 local gazetteers, government statistical records and remote-sensing land cover data from the Shandong Province. The study reconstructed the spatial distribution of the rate of reclaimed land at the county level and compared this map with a map of the current spatial distribution of suitable cropland. The following conclusions were drawn: (i) The rate of cultivated land grew exponentially. The extent of reconstruction in cropland areas during the 17(th) century, 18(th)~19(th) centuries, the beginning of the 20(th) century, the 1980 s, and the beginning of the 20(th) century are 4.51 mha, 6.51 mha, 7.52 mha, 8.53 mha and 11.80-12.00 mha, respectively. (ii) Several agricultural centers formed during the late 17(th) century. Until the beginning of the 20(th) century, the reclamation rate increased rapidly near the four southern lakes, which are located in the Zaozhuang and Linyi regions. (iii) Most reclamation activities before the 19(th) century occurred in suitable agricultural areas, and the cultivated land was already reclaimed by the beginning of the 20(th) century.