Climatically driven formation of the Tangxian planation surface in North China: An example from northwestern Zhongtiao Shan of the Shanxi Graben System

The development of planation surfaces requires stable tectonic and climatic conditions. However, it is difficult to discuss in detail how tectonic movement and/or climate change affects erosion, deposition, and uplift associated with the development, formation, and disintegration of planation surface. This article presents a case study on the development and formation of the Tangxian planation surface (TXPS) by establishing the magnetostratigraphy of one piedmont deposition section related to planation, and combining the depositional sequence overlying TXPS and basin sediments. Further, we discuss the role of tectonics and climate change in the geomorphic evolution of the TXPS during the late Cenozoic and revise the final formation age to be ca. 3.1 Ma by the relative deposition process. The vertical rates of the main fault constrained by different geomorphic surfaces and stable deposition in the basin show stable and moderate tectonic activity in the study area since the Pliocene, and a series of sedimentary records reveal that the climate in North China was stably warm-humid from the late Miocene to early Pliocene. Stable tectonic activity and stable climate were important bases for pediment development; however, abrupt climatic changes during the late Pliocene might be the main driving force of the final formation of the TXPS in North China.ISSN:1941-8264ISSN:1947-425

Detection of HPV DNA in esophageal cancer specimens from different regions and ethnic groups: a descriptive study

Abstract Background HPV has been found repeatedly in esophageal carcinoma tissues. However, reported detection rates of HPV DNA in these tumors have varied markedly. Differences in detection methods, sample types, and geographic regions of sample origin have been suggested as potential causes of this discrepancy. Methods HPV L1 DNA and HPV genotypes were evaluated in 435 esophageal carcinoma specimens collected from four geographic regions with different ethnicities including Anyang in north China, Shantou in south China, Xinjiang in west China, and the United States. The HPV L1 fragment was detected using SPF1/GP6+ primers. HPV genotyping was performed using genotype specific PCR. Results Two hundred and forty four of 435 samples (56.1%) tested positive for HPV L1. Significant differences in detection rate were observed neither among the three areas of China nor between China and the US. HPV6, 16, 18, 26, 45, 56, 57, and 58 were identified in L1 positive samples. HPV16 and 57 were the most common types in all regions, followed by HPV26 and HPV18. Conclusions HPV infection is common in esophageal carcinoma independent of region and ethnic group of origin. Findings in this study raise the possibility that HPV is involved in esophageal carcinogenesis. Further investigation with a larger sample size over broader geographic areas may be warranted.</p