The instability of wrist joint and total wrist replacement.

Total wrist arthroplasty are not used as widely as total knee and hip replacement. The functional hands are requiring surgeons to design a durable and functional satisfying prosthesis. This article will list the main reasons that cause the failure of the prosthesis.

[Method development for analysis of short-and long-chain perfluorocarboxylates in sewage].

A method using weak anion exchange cartridge for solid phase extraction before high performance liquid chromatography-negative electronspray ionization-tandem mass spectrometry [WAX-SPE + HPLC-ESI(-)-MS/MS] detection has been developed to measure C2-C14 perfluorocarboxylates (PFCAs) in sewages. When the weak anion exchange (WAX) cartridges were used for solid phase extraction (SPE), the better recoveries of short- and long-chain PFCAs (C2-C14) were achieved as the sewage samples were acidified to pH = 3.0 by formic acid, 2% formic acid was used for washing solvent and 1% ammonium hydroxide in methanol was used for elution solvent.