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Myanmar is the principal provider country of high-quality jadeite jade in the world, including so-called primary and secondary stones. The secondary stones occur as rounded pebbles, boulders, and blocks in eluvium–alluvium and often hold varying degrees of weathering. Unlike common rocks, such as granite, gabbro, schist, gneiss, and amphibolite, secondary jadeite stones frequently have weathered cortexes that vary in appearance, depth, texture, and mineral components compared with those of inner primary bodies. In this study, representative samples of secondary eluvial–deluvial jadeite stones with varying weathered cortexes were selected, and their appearances, textures, mineral components, and chemical composition features were analyzed. Their weathered cortexes were red, yellow, white, or black, and were 0.01–1.80 cm thick. The cortexes were opaque, often with soil luster and a fansha phenomenon. The body of the jade was usually translucent, and green and white in color. Along the border between the weathered cortex and the body of a certain jade stone, the textures were the same for the successive grain sizes. The only difference was that there were more cracks, cleavage planes, and fissures in the cortex. Jadeite was the main mineral component of both; however, minor late-stage supergene minerals (such as gibbsite, kaolinite, and halloysite) and Fe-bearing colloidal minerals were identified along the grain boundaries in the cortex. Studies of the textures and mineral components of weathered cortexes have gemmological applications including the identification and grading raw jadeite, as well as its design and carving. Moreover, such studies might provide information for improving our understanding of the unique weathering processes of monomineralic aggregates relative to multiple-mineral rocks, as well as gambling jadeite jade pieces through analyzing their cortex. [ABSTRACT FROM AUTHOR]

Background: Imported COVID-19 patients posed great challenges to border areas' COVID-19 control. However, research was scarce to reveal epidemiological characteristics of COVID-19 in border areas. This study aimed to explore the detailed transmission chains, and reveal epidemiological and clinical characteristics of the largest COVID-19 outbreak caused by Delta variant of concern (VOC) occurred in the China-Myanmar border area., Methods: During the outbreak from July to September, 2021 in Ruili City, Yunnan Province, China, epidemiological investigation data and clinical-related data pertaining to confirmed COVID-19 patients were collected. Patients' contact history data and viral gene sequencing were used for inference of transmission chains. Sociodemographic and epidemiological characteristics, cycle threshold (Ct) value, and antibodies level were compared between patients who were vaccinated against COVID-19 or not., Results: A total of 117 COVID-19 patients were confirmed during the outbreak, among which 86 (73.5%) were breakthrough infections. These patients evenly split between Chinese and Myanmar people (50.4% vs. 49.6%). Most of these patients were mild (45.3%) or moderate (48.7%) infections with no death reported. Multi-source of infection led to 16 transmission chains with a maximum of 45 patients in one chain. Patients vaccinated against COVID-19 before infection had relatively higher antibodies (IgM and IgG) levels and more rapid response to infection than non-vaccinated patients ( p < 0.05)., Conclusion: Land border areas have greater risks of imported COVID-19 and more complicated epidemics. It should be cautious in formulating entry and exit requirements for border areas. The immune effect of COVID-19 vaccines and related mechanism should be further explored., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yan, Hao, Wang, Wang, Zhang, Li, Jia, Chang, Zhang and Shui.)