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Taking the rotor system supported by angular contact ball bearing as the research object, the dynamic model of rotor bearing system is established by using Lagrange equation. Based on the Archard wear model, the calculation model of wear depth of bearing raceways considering lubrication effects is presented. The wear depth is introduced into the system dynamics model as the bearing clearance. The dynamic characteristics of rotor-bearing system and the evolution of bearing wear are carefully analyzed taking into account the rotor speed, bearing preload and disc position. The results show that the influence of bearing wear on dynamic characteristics of rotor-bearing system is closely related to rotor speed and bearing preload. Changing disc position does not lead to the significant variation of dynamic characteristics of rotor-bearing system with wear depth of bearing raceways. The rotor speed significantly affects the bearing wear, the bearing preload has very limited effect on bearing wear, and the variation of the disc position results in the weak difference of wear depth of bearings.

The precise disconnection of one type of chemical bond in polymers realizes high-yield recovery of valuable chemicals. In this study, we demonstrate a sustainable and efficient strategy to selectively cleave the specific sp3C–sp3N bond of a thermoset melamine–formaldehyde foam, by which valuable melamine of 99.5% purity was obtained with a yield of 95.3%. [ABSTRACT FROM AUTHOR]

As a kind of super stable thermoset resin, phenolic epoxy vinyl ester resin (PEVER) is widely applied as a solvent and corrosion resistant material. However, its highly cross-linked three-dimensional network challenges its degradation and recycling. In this study, we report an efficient catalytic system of KOH/C2H5OH–H2O to degrade PEVER under a mild reaction condition of 160 °C. It is discovered that the efficiency of KOH for degrading PEVER resulted from the high affinity of K+ to PEVER. Besides the resin, K+ shows good affinity to other organic substances, such as ethyl acetate, toluene, and petroleum ether, and it surpassed largely Na+ (NaOH) in the affinity to organic substances. The NMR and FT-IR characterizations indicated the degradation of PEVER via the hydrolysis of ester bonds, by which high value-added copolymer of styrene and methacrylic acid (SMAA), potassium salt of SMAA (SMAA-K), and novolac glycidyl ether (NOGE) were obtained. SMAA-K can be used as an interface modifier owing to its surface activity. The modified filter paper prepared by SMAA has high hydrophobicity. NOGE can be recycled to prepare a new polyurethane material. This study provides a new strategy for the chemical degradation and recycling of thermoset PEVER waste. [ABSTRACT FROM AUTHOR]

Background: Urine-derived stem cells (USCs) were considered to be an ideal source of stem cells for repairing urological diseases. However, the proliferative ability of USCs significantly decreased when cultured on plastic dishes, which limited their clinical application. It was found that collagen gels could promote the proliferation of USCs, but the underlying molecular mechanisms were unclear., Objective: The study aims to investigate the role of the mechanically activated cation channel Piezo1 and the transcriptional coactivator YAP in the regulation of proliferation of USCs on collagen gels., Methods: USCs were cultured on collagen gels (group COL), or plastic dishes (group NON). MTT assay, Scratch assay, EDU staining, and immunofluorescence (IF) of Ki67 were performed to evaluate the proliferation of USCs; IF of YAP was conducted to observe its nuclear localization; calcium imaging experiment was executed to evaluate the function of Piezo1; western blot was used to compare changes in protein expression of YAP, LATS1, ERK1/2, and p-ERK1/2. In addition, the regulatory effect of YAP on the proliferative capacity of USCs was confirmed by intervening YAP with its inhibitor verteporfin (VP); and the inhibitor or activator of Piezo1, GsMTx4 or Yoda1 was used to explore the effect of Piezo1 on the nuclear localization of YAP, the proliferation of USCs and the regeneration of injured bladder., Results: The results showed that cell proliferation was significantly enhanced in USCs in the COL group with the nuclear accumulation of YAP compared with the NON group and VP attenuated these effects. The expression and function of Piezo1 were higher in the COL group compared with the NON group. Blockage of Piezo1 by GsMTx4 decreased nuclear localization of YAP, the proliferation of USCs, and caused the failure of bladder reconstruction. Activation of Piezo1 by Yoda1 increased the nuclear expression of YAP, and the proliferation of USCs, which further improved the regeneration of the injured bladder. Finally, the ERK1/2 rather than LATS1 was revealed to participate in the Piezo1/YAP signal cascades of USCs proliferation., Conclusion: Taken together, Piezo1-ERK1/2-YAP signal cascades were involved in regulating the proliferation ability of USCs in collagen gels which would be beneficial for the regeneration of the bladder., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Introduction: Acute kidney injury (AKI) was a disease with a high mortality mainly caused by renal ischemia/reperfusion injury (I/R). Although the current non-targeted administration of vascular endothelial growth factor (VEGF) for AKI had been revealed to facilitate the recovery of renal I/R, how to targeted deliver VEGF and to retain it efficiently in the ischemic kidney was critical for its clinical application., Methods: In present study, bi-functional KIT-PR1P peptides were constructed which bond VEGF through PR1P domain, and targeted ischemic kidney through KIT domain to interact with biomarker of AKI-kidney injury molecule-1 (Kim-1). Then the targeted and therapeutic effects of KIT-PR1P/VEGF in AKI was explored in vitro and in vivo ., Results: The results showed KIT-PR1P exhibited better angiogenic capacity and targeting ability to hypoxia HK-2 cells with up-regulated Kim-1 in vitro . When KIT-PR1P/VEGF was used for the treatment of renal I/R through intravenous administration in vivo , KIT-PR1P could guide VEGF and retain its effective concentration in ischemic kidney. In addition, KIT-PR1P/VEGF promoted angiogenesis, alleviated renal tubular injury and fibrosis, and finally promoted functional recovery of renal I/R., Conclusion: These results indicated that the bi-functional KIT-PR1P peptides combined with VEGF would be a promising strategy for the treatment of AKI by targeting to Kim-1., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© 2023 The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.)