Preparation and application of hydroxyapatite（HA） nanoparticles/NR2B-siRNA complex

Hydroxyapatite（HA） nanoparticles were prepared by coprecipitation-hydrothermal synthesis and their exosyndrome was estimated via transmission electron microscopy. Agarose gel electrophoresis and ultraviolet spectrophotometry were used to evaluate the ability of HA to bind NR2B-siRNA at different pH values and at different HA：NR2B-siRNA ratios. And the stability of the complex in saline was also evaluated. The effect of HA/NR2B-siRNA complex on chronic inflammatory pain was evaluated in vivo, in mice. Transmission electron microscopy（TEM） reveals that HA nanoparticles are thin strips or short rod in shape and thc one-dimensional particle size of HA nanoparticles is 40-50 nm. Under the acid or neutral condition, the Zeta potential of HA is positive; nanoparticles can completely bind NR2B-siRNA when the HA：NR2B-siRNA ratio is at or larger than 35：1; while under the alkaline condition, the affinity of HA to NR2B-siRNA is rather weak. HA/NR2B-siRNA complex is not dissociated when being resuspended in saline. The nociception of the tonic phase induced by formalin is significantly reduced in the HA：NR2B-siRNA treated mice as compared with the. controls. Therefore, HA may be a new siRNA nano-vector material.     

Solid-phase extraction of trace Au（Ⅲ） with SDG and determination by the catalytic spectrophotometric method

The new catalytic kinetic spectrophotometric method for Au(III) determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate ((NH4)2S2O8) with nitrilo triacetic acid as an activator in mi- croemulsion and H2SO4 medium. Under optimum conditions, there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au(III) at 520 nm. The relative standard deviation was 3.0% with a correlation coefficient of 0.9986. The detection limit achieved was 9.75 × 10-5 μg/mL. A new method using a column packed with sulfhydryl dextrose gel (SDG) as a solid-phase extractant has been developed for the preconcentration and separation of Au(III) ions. The method has been applied to the determination of trace gold with satisfactory results.     

Effects of rare earth La on the microstructure and melting property of（Ag-Cu28）-30Sn alloys prepared by mechanical alloying

To obtain novel intermediate temperature alloy solders with a melting temperature of 400-600°C,nominal(Ag-Cu28)-30Sn alloys without or with a trace addition(0.5 or 1.0 wt.%) of rare earth(RE) element La were prepared by mechanical alloying.The aim of this research is to investigate the effects of the addition of La on the microstructures,alloying process and melting properties of(Ag-Cu28)-30Sn alloys.The results show that the addition of La produces no new phase.A trace amount of La addition can effectively refine the grain size,but the excessive addition of 1.0 wt.% La inhibits the alloying process.The influence of La on the melting temperatures of solder alloys is negligible.However,the trace addition of 0.5 wt.% La can distinctly reduce the fusion zone and improve the melting property of(Ag-Cu28)-30Sn alloys.