ABSTRACT
Objective To develop a N95 filter device for medical gas terminal to remove bacteria,viruses,particles and impurities from medical gas so as to purify medical gas to sterile grade.Methos The device was composed of a filter element and a shell,and the two parts were gifted with cylindrical shape to enlarge filtration area and reduce airflow resistance.The filter element had its length being 110 mm and diameter being 40 mm,and was composed of a tubular plastic frame and high-performance N95 filter cotton with high filtration rate.The top of the filter element was fixed to the inlet end of the device,and the bottom was fastened to the outlet end by splicing.The device with a total length of 150 mm had its shell and joint made of plastics,and was 110-mm long at the inlet end and 60-mm long at the outlet end.The outside diameter of the device was 60 mm,the connection thread at the middle of the device was 20-mm long,and the cones at the two ends had a 30-mm diameter.The joints at the ends had their sizes being 5 mm according to industrial standard,which were used to connect the device with the oxygen tube.Results The device had the filtration rate being higher than 99.9％ for both particle filtration efficiency and bacterial filtration efficiency,and the desired requirements were met.Conclusion The device gains advantages when filtering bacteria,virus and particles,and thus is worthy promoting clinically.
ABSTRACT
<p><b>OBJECTIVE</b>To determine the effects of KH2PO4 on the odonto- and osteogenic differentiation potential of human stem cells from apical papillae (SCAP) in vitro.</p><p><b>METHODS</b>SCAP were isolated and cultured respectively in alpha minimum essential medium (α-MEM) or α-MEM containing 1.8 mmol/L KH2PO4. Alkaline phosphatase (ALP) activity, alizarin red staining, real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting were used to examine the odonto and osteogenic potential of SCAP in the two media.</p><p><b>RESULTS</b>SCAP cultured in α-MEM containing 1.8 mmol/L KH2PO4 exhibited a higher ALP activity [(0.370 ± 0.013) Sigma unit×min(-1)×mg(-1)] at day 3 than control group [(0.285 ± 0.008) Sigma unit×min(-1)×mg(-1)] and KH2PO4-treated SCAP formed more calcified nodules at day 5 [(0.539 ± 0.007) µg/g] and day 7 [(1.617 ± 0.042) µg/g] than those in normal medium [(0.138 ± 0.037) µg/g, P < 0.01]. The expression of odonto- and osteogenic markers were significantly up-regulated after the stimulation of KH2PO4 at day 3 and 7 respectively, as compared with control group.</p><p><b>CONCLUSIONS</b>1.8 mmol/L KH2PO4 can promote the odonto and osteogenic differentiation potential of human SCAP.</p>