Co-doping of hydroxyapatite with zinc and fl uoride improves mechanical and biological properties of hydroxyapatite

Hydroxyapatite(HA) co-doped with Zn2+ tand F- ions was synthesized by precipitation method for the first time in this study.FTIR spectroscopy revealed Zn2+ tand F ions incorporation into HA structure.Co-doping of Zn2+ tand F- ions decreased unit cell volume of HA and decreased grain sizes.Zn2+ tor 5 mol% F addition into HA significantly improved its density.Microhardness was increased with Zn2+ taddition and further increase was detected with F co-doping.Zn2+ tand F co-doped samples had higher fracture toughness than pure HA.Zn2+ tincorporation to the structure resulted in an increase in cell proliferation and ALP activity of cells,and further increase was observed with 1 mol%F addition.With superior mechanical properties and biological response 2Zn1 F is a good candidate for biomedical applications.     

A central role for JNK in obesity and insulin resistance

Obesity is closely associated with insulin resistance and establishes the leading risk factor for type 2 diabetes mellitus, yet the molecular mechanisms of this association are poorly understood. The c-Jun amino-terminal kinases (JNKs) can interfere with insulin action in cultured cells and are activated by inflammatory cytokines and free fatty acids, molecules that have been implicated in the development of type 2 diabetes. Here we show that JNK activity is abnormally elevated in obesity. Furthermore, an absence of JNK1 results in decreased adiposity, significantly improved insulin sensitivity and enhanced insulin receptor signalling capacity in two different models of mouse obesity. Thus, JNK is a crucial mediator of obesity and insulin resistance and a potential target for therapeutics.