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35 results on '"Zhou, Haobo"'

10. FOXL2regulates RhoAexpression to change actin cytoskeleton rearrangement in granulosa cells of chicken pre-ovulatory follicles†

Author

Li, Xuelian, Du, Hongting, Zhou, Haobo, Huang, Ying, Tang, Shuixin, Yu, Chengzhi, Guo, Yan, Luo, Wei, and Gong, Yanzhang

Abstract

Forkhead box L2 (FOXL2) is an indispensable key regulator of female follicular development, and it plays important roles in the morphogenesis, proliferation, and differentiation of follicle granulosa cells, such as establishing normal estradiol signaling and regulating steroid hormone synthesis. Nevertheless, the effects of FOXL2on granulosa cell morphology and the underlying mechanism remain unknown. Using FOXL2 ChIP-seq analysis, we found that FOXL2 target genes were significantly enriched in the actin cytoskeleton-related pathways. We confirmed that FOXL2inhibited the expression of RhoA, a key gene for actin cytoskeleton rearrangement, by binding to TCATCCATCTCT in RhoApromoter region. In addition, FOXL2overexpression in granulosa cells induced the depolymerization of F-actin and disordered the actin filaments, resulting in a slowdown in the expansion of granulosa cells, while FOXL2silencing inhibited F-actin depolymerization and stabilized the actin filaments, thereby accelerating granulosa cell expansion. RhoA/ROCK pathway inhibitor Y-27632 exhibited similar effects to FOXL2overexpression, even reversed the actin polymerization in FOXL2silencing granulosa cells. This study revealed for the first time that FOXL2regulated granulosa cell actin cytoskeleton by RhoA/ROCK pathway, thus affecting granulosa cell expansion. Our findings provide new insights for constructing the regulatory network of FOXL2and propose a potential mechanism for facilitating rapid follicle expansion, thereby laying a foundation for further understanding follicular development.FOXL2regulates actin cytoskeleton rearrangement of granulosa cells (GCs) through RhoA/ROCK pathway, thus affecting GC expansion of pre-ovulatory follicles in chicken.Graphical Abstract

Published
2024
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28. A new utility calculation model for axial flow of non-Newtonian fluid in concentric annuli

Author

Zhou Haobo, Zhai Yinghu, Fan Honghai, and Peng Qi

Subjects
General Chemical Engineering, Reynolds number, Herschel–Bulkley fluid, Geometry, Mechanics, Non-Newtonian fluid, Pipe flow, Physics::Fluid Dynamics, symbols.namesake, Generalized Newtonian fluid, Newtonian fluid, Fluid dynamics, symbols, Shear flow, Mathematics
Abstract

A new utility approach that is independent of the rheological model is presented for the flow of non-Newtonian fluids in concentric annulus. The novel model was developed without assuming that the generalised flow index remains constant over all shear rate ranges. Based on the slot model, the flow rate expressions for all common rheological models flowing in annuli were obtained, such as the Herschel–Bulkley model, the Robertson–Stiff model, and the Four-parameter model, and they all can be solved numerically to obtain accurate wall shear rate and shear stress. Following Metzner and Reed's study, we defined a generalised flow index for non-Newtonian fluid flow in annuli. Through a theoretical analysis, we also defined a new effective diameter for non-Newtonian fluid flow in annuli, which accounts for the effects both of annulus geometry and fluid rheology but which is different from that was proposed by Reed and Pilehvari. Through the generalised effective diameter we linked non-Newtonian annular flow with Newtonian pipe flow. A general annular Reynolds number expression was derived from this method for conditions under which the generalised flow index is variable. A theoretical calculation method for the generalised flow index and a uniform pressure loss calculation model for non-Newtonian flow in concentric annuli were developed, which are applicable to all time-independent non-Newtonian fluid. The predictions of this model have been compared with an extensive set of data from the literature. The comparisons of different fluids in different size annuli show very good agreement over the entire range of flow types.

Published
2014

35. Application prospect of MPD technology in shale gas drilling.

Author

TANG Shoubao, LU Qian, SONG Yilei, LI Mingjian, and ZHOU Haobo

Abstract

As the exploration and development of domestic shale gas continue, the complex incidents we encountered during drilling are also increasingly prominent. For the shale formations which is leaky and have complex lithology in South China, MPD is necessary to learn to drill through the complicated shale interval in a fast, safe and efficient manner and to break these common technical challenges of drilling. Currently, southern Yangtze region mainly develops two sets of shale formations, Silurian Longmaxi and Cambrian Niutitang. However, there are less pure shale section, complicated lithology and serious fragmentation. According to the data of shale gas drilling, the limy, silty and siliceous shale is often met during drilling, frequently accompanied with overflow and lost circulation. For the target interval with thickly developed shale bed, the density window of drilling fluid is small and the well wall is extremely unstable. According to the lithologic development of shale bed, technical characteristics of MPD, lab analysis, current MPD supporting equipment and other relevant factors, the MPD in bottom hole constant pressure method can be used to drill through the large and complicated shale interval. [ABSTRACT FROM AUTHOR]

Published
2014
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