An invasive podosome-like structure promotes fusion pore formation during myoblast fusion

An F-actin–enriched protrusion resembling an invasive podosome promotes fusion pore formation between muscle founder cells and fusion-competent myoblasts

Preparation of MOF-Based Core-Shell Gel Particles with Catalytic Activity and Their Plugging Performance

Drilling fluid systems for deep and ultra-deep wells are hampered by both high-temperature downhole environments and lengthy cycle periods. Suppose that the gel particle-plugging agent, the primary treatment agent in the system, fails to offer durable and stable plugging performance. In such a scenario, the borehole wall is susceptible to instability and landslide after prolonged immersion, leading to downhole accidents. In this study, novel core-shell gel particles (modified ZIF) with ZIF particles employed as the core material and organosilicon-modified polyethylene polyamine (PEPA) as the polymer shell were fabricated using PEPA, in-house synthesized (3-aminopropyl) triethoxysilane (APTS), and the ZIF-8 metal-organic framework (MOF) as the raw materials to enhance the long-term plugging performance of gel plugging agents. The modified ZIF particles are nanoscale polygonal crystals and differ from conventional core-shell gel particles in that they feature high molecular sieve catalytic activity due to the presence of numerous interior micropores and mesopores. As a result, modified ZIF exhibits the performance characteristics of both rigid and flexible plugging agents and has an excellent catalytic cross-linking effect on the sulfonated phenolic resin (SMP-3) and sulfonated lignite resin (SPNH) in drilling fluids. Consequently, a cross-linking reaction occurs when SMP-3 and SPNH flow through the spacings in the plugging layer formed by the modified ZIF particles. This increases the viscosity of the liquid phase and simultaneously generates an insoluble gel, forming a particle-gel composite plugging structure with the modified ZIF and significantly enhancing the long-term plugging performance of the drilling fluid

Mitogen-Activated Protein Kinases and Hypoxic/Ischemic Nephropathy

Tissue hypoxia/ischemia is a pathological feature of many human disorders including stroke, myocardial infarction, hypoxic/ischemic nephropathy, as well as cancer. In the kidney, the combination of limited oxygen supply to the tissues and high oxygen demand is considered the main reason for the susceptibility of the kidney to hypoxic/ischemic injury. In recent years, increasing evidence has indicated that a reduction in renal oxygen tension/blood supply plays an important role in acute kidney injury, chronic kidney disease, and renal tumorigenesis. However, the underlying signaling mechanisms, whereby hypoxia alters cellular behaviors, remain poorly understood. Mitogen-activated protein kinases (MAPKs) are key signal-transducing enzymes activated by a wide range of extracellular stimuli, including hypoxia/ischemia. There are four major family members of MAPKs: the extracellular signal-regulated kinases-1 and -2 (ERK1/2), the c-Jun N-terminal kinases (JNK), p38 MAPKs, and extracellular signal-regulated kinase-5 (ERK5/BMK1). Recent studies, including ours, suggest that these MAPKs are differentially involved in renal responses to hypoxic/ischemic stress. This review will discuss their changes in hypoxic/ischemic pathophysiology with acute kidney injury, chronic kidney diseases and renal carcinoma

Major Differences in Hypoxia Tolerance and P38 Regulation Among Different Renal Cells

Background/Aims: Mitogen-activated protein kinases (MAPKs) are involved in the cellular response to hypoxia and their dysregulation may contribute to the progression and pathology of diverse human renal diseases. Recent studies suggest that the regulation of MAPK responses to hypoxic stress may be different in different cells, even within the same organ. However, it is unclear if MAPKs are differentially regulated in different renal cells in hypoxia. This work was carried out to clarify this fundamental issue. Methods: We cultured normal rat kidney epithelial (NRK-52E) cells, human kidney epithelial (HK-2) cells and human renal cell adenocarcinoma (769-P) cells simultaneously under normoxia and hypoxia (1% O2) for 24-72 hours. The protein levels of P-ERK1/2, ERK1/2, P-p38, p38 and eEF2K were detected by western blotting. The morphology of all cells was examined using light microscopy. Results: Under the same hypoxic condition, P-ERK1/2 was up-regulated in all renal cells. Meanwhile,P-p38 in NRK-52E cells was markedly increased after hypoxia for 24-72 hours, while it appeared to show no appreciable change in HK-2 and 769-P cells exposed to hypoxia for 24-48 hours and significantly decreased in these cells after 72 hours hypoxia. On the other hand, hypoxia markedly down-regulated the expression of eukaryotic elongation factor-2 kinase (eEF2K) in all three cells. Under microscopy, NRK-52E cells had no visible injury after 72 hours hypoxia, while HK-2 and 769-P cells were mostly damaged under the same condition. Conclusions: Our data suggest that in response to prolonged hypoxic stress, ERK1/2 and p38 are differentially regulated in three renal cells, while eEF2K is largely down-regulated in all of these cells

Accommodation of Two-Dimensional SiO_<i>x</i> in a Point-to-Plane Conductive Network Composed of Graphene and Nitrogen-Doped Carbon for Robust Lithium Storage

Silicon oxides (SiOx) are one of the most promising anode materials for next-generation lithium-ion batteries owing to their abundant reserve and low lost and high reversible capacity. However, the practical application of SiOx is still hindered by their intrinsically low conductivity and huge volume change. In this regard, we design a novel anode material in which sheet-like SiOx nanosheets are encapsulated in a unique point-to-plane conductive network composed of graphene flakes and nitrogen-doped carbon spheres. This unique composite structure demonstrates high specific capacity (867.7 mAh g–1 at 0.1 A g–1), superior rate performance, and stable cycle life. The electrode delivers a superior reversible discharge capacity of 595.8 mAh g–1 after 200 cycles at 1.0 A g–1 and 287.5 mAh g–1 after 500 cycles at 5.0 A g–1. This work may shed light on the rational design of SiOx-based anode materials for next-generation high-performance lithium-ion batteries