Objective To investigate the NOx(nitrogen oxides,esp.NO2) output of household ozone generator and the control method.Methods Ion chromatogram,pH detection and iodine titration were used to study the outputs of ozone and the by-product,NOx,generated by some certain household ozone generator in normal operation condition.The method of controlling NO2 simply by pure water absorption was also studied.Results At about 15 min,the ozone generator produced NO2 and turned into NO3-,the amount increased along with the operating time.After 60 min,the NO3-was almost in proportion to the operating time,the pH value decreased clearly.pH value was a proper and simple substitute parameter to display the generation and accumulation of NO2.NO2 could be efficiently controlled by pure water absorption.NO3-absorbed in a 0.1 mol/L NaOH solution was less than 0.01 mg/L after a pure water absorber which had an effective depth of 12cm,with little influence of ozone production.Conclusion NO2 will be generated inevitably and the amount of the by-product increases with the running time of the household ozone generator.Pure water absorption is efficient to control NO2 generation.

Objective: To investigate the mechanical property,biocompatibility,and osteogenic differentiation ability of chitosan-β-TCP( CS-β-TCP) scaffold,meanwhile,to study the possibility of the composite as a scaffold to repair bone defect. Methods: Briefly,the CS-β-TCP composite scaffold was fabricated utilizing bidirectional lyophilization technique. Then,the scaffold micro-structure was observed by scanning electron microscopy( SEM),X-ray diffraction( XRD) and energy disperse spectroscopy( EDS) were employed to analyze the ingredients and elements distribution of scaffold,respectively. Additionally,the compression strength of the scaffold was tested by mechanical universal testing machine. The biocompatibility of the scaffold and the cell viability research were characterized via CCK-8 assay and Live/Dead staining,respectively,and the cell adhesion was studied by DPAI/Phalloidine fluorescence staining. qRT-PCR was employed to investigate the expression level of osteogenic-related gene such as BMP2,RUNX2 and COL1. ALP staining was carried out to measure the osteogenic differentiation effect of BMSCs. Results: The CS-β-TCP scaffold was comprised of bulk parallel,aligned and thin lamellas with many porous structures. β-TCP particles were evenly distributed over CS framework layers and the CS-β-TCP scaffold possess excellent elastic property and biocompatibility,moreover,the cell seeded on scaffold revealed high cell viability and continuous proliferation. qRT-PCR and ALP staining results demonstrated that the CS-β-TCP scaffold could induce osteogenic differentiation of BMSC. Conclusion To sum up,the CS-β-TCP scaffold expressed desired mechanical and biological properties,and could induce BMSC differentiate into osteoblast,the composite scaffold provided a promising strategy for bone defect regeneration.