Leaves Based Lubricant Additive Towards Improving Tribological Properties

Three kinds of crop leaf-surface waxes were extracted from wheat,corn and broomcorn leaves,respectively.The crop leaf-surface waxes as lubricant additives were added to synthetic ester and the friction and wear properties of prepared lubricants for steel-aluminum and steel-copper friction pair were investigated in detail.The scanning electron microscopy(SEM)and secondary ion mass spectrometry(SIMS)were employed to explore the friction mechanisms.The results show that crop leaf-surface waxes could successfully reduce the friction and wear of steel-aluminum and steel-copper sliding friction pairs as compared with pure synthetic ester.For example,when the concentration of wheat leaf-surface wax as additive was 2%,the COFs was decreased by 58%;the four additives can be ranked by the anti-wear capability as follows:Corn>Wheat>Glycerol>Broomcorn to steel-aluminum sliding friction pairs.The SIMS spectra of positive and negative ions on the worn surfaces have reduced the exposure of Al and increased short chain ions counts.The good friction reduction and antiwear abilities are attributed to the adsorption or reaction films formed by leafsurface wax on worn surface.

The First Crested Duck Genome Reveals Clues to Genetic Compensation and Crest Cushion Formation

The Chinese crested(CC)duck is a unique indigenous waterfowl breed,which has a crest cushion that affects its survival rate.Therefore,the CC duck is an ideal model to investigate the genetic compensation response to maintain genetic stability.In the present study,we first generated a chromosome-level genome of CC ducks.Comparative genomics revealed that genes related to tissue repair,immune function,and tumors were under strong positive selection,indicating that these adaptive changes might enhance cancer resistance and immune response to maintain the genetic stability of CC ducks.We also assembled a Chinese spot-billed(Csp-b)duck genome,and detected the structural variations(SVs)in the genome assemblies of three ducks(i.e.,CC duck,Csp-b duck,and Peking duck).Functional analysis revealed that several SVs were related to the immune system of CC ducks,further strongly suggesting that genetic compensation in the anti-tumor and immune systems supports the survival of CC ducks.Moreover,we confirmed that the CC duck originated from the mallard ducks.Finally,we revealed the physiological and genetic basis of crest traits and identified a causative mutation in TAS2R40 that leads to crest formation.Overall,the findings of this study provide new insights into the role of genetic compensation in adaptive evolution.

A synergetic strategy based on laser surface texturing and lubricating grease for improving the tribological and electrical properties of Ag coating under current-carrying friction

Herein,a series of Ag coatings with different micro‐dimples were fabricated on copper surfaces by laser surface texturing(LST)and magnetron sputtering.Multilayer graphene lubricating grease(MGLG)was prepared using multilayer graphene as an additive.The textured Ag coatings and MGLG were characterized.Moreover,the tribological and electrical performances of the textured Ag coatings under MGLG lubrication were investigated in detail.Results demonstrated that the textured Ag coating with an appropriate dimple diameter could exhibit improved tribological and electrical properties when compared to the non‐textured Ag coating under MGLG lubrication.The characterization and analysis of the worn surfaces suggest that the synergetic effect of LST and MGLG contributes to these excellent tribological and electrical properties.

Establishment and Characterization of a Cell Based Artificial Antigen-Presenting Cell for Expansion and Activation of CD8^+ T Cells Ex Vivo

Artificial antigen-presenting cells are expected to stimulate the expansion and acquisition of optimal therapeutic features of T cells before infusion. Here CD32 that binds to a crystallizable fragment of IgG monoclonal antibody was genetically expressed on human K562 leukemia cells to provide a ligand for T-cell receptor. CD86 and 4-1BBL, which are ligands of co-stimulating receptors of CD28 and 4-1BB, respectively, were also expressed on K562 cells. Then we accomplished the artificial antigen-presenting cells by coupling K32/CD86/4-1BBL cell with OKT3 monoclonal antibody against CD3, named K32/CD86/4-1BBL/OKT3 cells. These artificial modified cells had the abilities of inducing CD8^＋ T cell activation, promoting CD8^＋ T cell proliferation, division, and long-term growth, inhibiting CD8^＋ T cell apoptosis, and enhancing CD8^＋ T cell secretion of IFN-T and perforin. Furthermore, antigen-specific cytotoxic T lymphocytes could be retained in the culture stimulated with K32/CD86/4-1BBL/OKT3 cells at least within 28 days. This approach was robust, simple, reproducible and economical for expansion and activation of CD8^＋ T cells and may have important therapeutic implications for adoptive immunotherapy. Cellular ＆ Molecular Immunology.

Nano-montmorillonite-doped lubricating grease exhibiting excellent insulating and tribological properties

Three types of nano-montmorillonite were doped as additives to afford lubricating greases.The physicochemical,insulating,and tribological performances of the obtained lubricating greases were investigated in detail.Furthermore,the tribological action mechanisms were analyzed by high magnification optical microscope,Raman spectroscopy,and energy dispersive X-ray spectroscope (EDS).The results show that the inorganic modification montmorillonite (IOMMT) can significantly increase the number of electron traps in the base grease,leading to excellent insulating performances.Moreover,IOMMT as a novel lubricant additive (1.5 wt％ in grease) significantly enhances the friction reducing and anti-wear abilities for steel/steel contact that comprises a unique layered structure to prevent friction between the contact pairs and the protective tribofilm generated by physical adsorption and chemical reaction.