27 research outputs found

    A Review of Surface Treatments for Sliding Bearings Used at Different Temperature

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    The boundary lubrication and dry friction of plain bearings at different work temperature are unable to be avoided under the start and stop condition. The poor lubrication is one reason of bearing broken. In order to improve the tribological properties and select the best treatment for different bearings used at different temperature, the studies of different treatment technologies are reviewed in this paper. The review shows that the shortages of bonding fiber woven materials, inlaying solid lubricating materials, electro plating and magnetron sputtering are poor temperature resistance, low load capacity, environment pollution and low production efficiencies respectively. Based on the analyses and summaries, the liquid dope spraying and thermal powder spraying are suggested to deposit coating on the surface of bearing which working temperature is lower than 200 and above 800°C respectively. However, the technology processes, the mechanisms of spraying and self-lubrication materials should be studied further and deeply

    Single-Cell Transcriptome Analyses Reveal Signals to Activate Dormant Neural Stem Cells

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    SummaryThe scarcity of tissue-specific stem cells and the complexity of their surrounding environment have made molecular characterization of these cells particularly challenging. Through single-cell transcriptome and weighted gene co-expression network analysis (WGCNA), we uncovered molecular properties of CD133+/GFAP− ependymal (E) cells in the adult mouse forebrain neurogenic zone. Surprisingly, prominent hub genes of the gene network unique to ependymal CD133+/GFAP− quiescent cells were enriched for immune-responsive genes, as well as genes encoding receptors for angiogenic factors. Administration of vascular endothelial growth factor (VEGF) activated CD133+ ependymal neural stem cells (NSCs), lining not only the lateral but also the fourth ventricles and, together with basic fibroblast growth factor (bFGF), elicited subsequent neural lineage differentiation and migration. This study revealed the existence of dormant ependymal NSCs throughout the ventricular surface of the CNS, as well as signals abundant after injury for their activation

    Some inequalities involving the polygamma functions

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    Abstract Let ψn(x)=(−1)n−1ψ(n)(x) ψn(x)=(−1)n−1ψ(n)(x)\psi _{n}(x)=(-1)^{n-1}\psi ^{(n)}(x), where ψ(n)(x) ψ(n)(x)\psi ^{(n)}(x) are the polygamma functions. We determine necessary and sufficient conditions for the monotonicity and convexity of the function F(x;α,β)=ln(exp(αψ(x+β))ψn(x))−ln(n−1)!,x>max(0,−β), F(x;α,β)=ln⁡(exp⁡(αψ(x+β))ψn(x))−ln⁡(n−1)!,x>max⁡(0,−β), F(x;\alpha ,\beta )=\ln \bigl(\exp \bigl(\alpha \psi (x+\beta )\bigr)\psi _{n}(x) \bigr)- \ln (n-1)!, \quad x>\max (0,-\beta ), for α and β∈R β∈R\beta \in \mathbb{R}, where ψ(x) ψ(x)\psi (x) is the psi function. Consequently, this yields not only some new inequalities for the polygamma functions, but also new star-shaped and superadditive functions involving them. In addition, we improve a well-known mean-value inequality for the polygamma functions

    110th Anniversary

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    MiR-373-3p Promotes Invasion and Metastasis of Lung Adenocarcinoma Cells

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    Background and objective Lung cancer is the leading cause of cancer-related deaths worldwide, and metastasis is the major cause of death in lung cancer patients. MiR-373 is closely associated with invasion and metastasis in other tumor cells. This study explored the expression of miR-373-3p in non-small cell lung cancer (NSCLC) and its effect on the invasive and metastatic capabilities of lung adenocarcinoma cells, as well as their mechanisms of action. Methods The expression of miR-373-3p in NSCLC tissues and lung adenocarcinoma cell lines was detected by quantitative reverse transcription polymerase chain reaction. The roles of miR-373-3p in regulating lung adenocarcinoma cell invasion and metastatic properties were analyzed with miR-373-3p mimic/inhibitor-transfected cells via Transwell chamber assay. Matrix metalloproteinase MMP-9 and MMP-14 protein levels were detected by Western blot in lung cancer cells after transfection. Results MiR-373-3p was upregulated in 51 NSCLC tissues and 5 NSCLC cell lines. Gain-of-function and loss-of-function studies showed that overexpression of miR-373-3p promoted H1299 cell migration and invasion, which resulted in upregulation of MMP-9 and MMP-14. By contrast, miR-373-3p knockdown inhibited these processes in A549 cells and downregulated the expression of MMP-9 and MMP-14. Conclusion Our results demonstrated that miR-373-3p participated in the invasion and metastasis of lung adenocarcinoma cells, partly by upregulation of MMP-9 and MMP-14

    Highly soluble organic nitrate additives for practical lithium metal batteries

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    Abstract The stability of lithium metal anodes essentially dictates the lifespan of high‐energy‐density lithium metal batteries. Lithium nitrate (LiNO3) is widely recognized as an effective additive to stabilize lithium metal anodes by forming LiNxOy‐containing solid electrolyte interphase (SEI). However, its poor solubility in electrolytes, especially ester electrolytes, hinders its applications in lithium metal batteries. Herein, an organic nitrate, isosorbide nitrate (ISDN), is proposed to replace LiNO3. ISDN has a high solubility of 3.3 M in ester electrolytes due to the introduction of organic segments in the molecule. The decomposition of ISDN generates LiNxOy‐rich SEI, enabling uniform lithium deposition. The lifespan of lithium metal batteries with ISDN significantly increases from 80 to 155 cycles under demanding conditions. Furthermore, a lithium metal pouch cell of 439 Wh kg−1 delivers 50 cycles. This work opens a new avenue to develop additives by molecular modifications for practical lithium metal batteries
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