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Medium-coarse-crystalline dolomite is a major variant of dolomite, and its structural heterogeneity inside and outside the crystals makes it an ideal vehicle for studies of dolomite genesis, fluid evolution and elemental migration. In this paper, the medium-coarse crystalline dolomite from the fifth section of the Majiagou Formation of the Lower Ordos Basin was systematically studied by petrographic, cathodoluminescence and related geochemical methods. The rock is developed in the context of mud powder crystal dolomite and granular dolomite, possessing significant ring band structure, fluorite and quartz intergrowth. Compared with other dolomites, it is characterized by Fe and Mn enrichment and low Na and Sr contents, as well as a negative δEu anomaly and a strong negative δ18 O offset. Combined with the evolutionary history of diagenesis, it is believed that the medium-coarse-crystal dolomite is the end product of a series of diagenetic effects such as early dolomitization-atmospheric freshwater leaching-secondary burial recrystallization-deep burial dissolution. Electron microprobe analysis reveals the structural and compositional heterogeneity inside and outside the crystals. The formation of mediumcoarse- crystalline dolomite is associated with an increase in Fe-Mn content, a rise in the Mn/Sr ratio, a decrease in Sr, and a first rise and then a fall in Na concentration. This study provides a valuable reference for further research on the genesis of the medium-coarse crystalline dolomite. [ABSTRACT FROM AUTHOR]

The bursa of Fabricius plays an essential role in B lymphocyte development, which is controlled not only by proteins but by noncoding RNA. Circular RNA (circRNA) are expressed in diverse tissues in eukaryotes. To acquire a deeper perception of the molecular mechanism of bursal development, RNA sequencing was used to identify the circRNA during varied evolving stages of the chicken bursa of Fabricius. We identified 13,689 circRNA. All these circRNA were originated from 4565 chicken genes. Among them, only 1 circRNA was yielded from those 4131 parental genes, and 2 or more circular isoforms were generated from the remaining genes. There were 27 circRNA found to be differentially expressed between the embryonic day 20 and day 2 developmental stages. The 5 isoforms of immunoglobulin lambda-like polypeptide 1 circRNA were tested to validate the RNA sequencing data, and their targeted genes were also analyzed with quantitative reverse transcription PCR. These data indicate that cirRNA are abundant and essential during bursal development and may play essential roles in the development of bursa of Fabricius. [ABSTRACT FROM AUTHOR]