ABSTRACT
Objective To find a new material for biomedical scaffold.Methods Composite films from poly-L-lactic acid(PLLA)and opal powder were fabricated.Osteoblasts seeded on the composite films and control ones were examined.Cell densities and morphologies on these films were studied by scanning electron microscopy(SEM).Cell growth and differential function were assessed by 3-(4,5-dimethyltyiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT)test.Results SEM study showed that the addition of powder could improve the adhesion between osteoblasts and the composite films.MTT test proved that cell proliferation was improved when opal powder was added.This improvement came from the negative ion given off by the opal powder.The negative ions either accumulate at the cell membrane or enter into the cells.Accumulation of negative ions at the cell membrane leads to a change of electric potential difference across the cell membrane which should be in a proper range for the cells to perform their normal physiological function.If the negative ions enter the cells,they may take part in biochemical reactions whenever possible.In this way,the ions also affect the cell normal metabolism.Conclusion Osteoblasts grow well on opal/PLLA composites and the negative ion from opal powder is responsible for the enhancement of cell growth.This study provides a new material for biomedical scaffold.
ABSTRACT
It is believed that one of the principal effects of negative air ion is refreshing human psychological condition. Negative air ion can be observed in natural environments such as forest, fountain, and hot spring. In order to elucidate scientific reason of psychological effects by negative air ions, quantifying psychological effects will be important.<br>Healthy sixteen examinees (8 young candidates around 20 years, 8 old candidates around 60 years) are tested by SRS-18, blood pressure, questionnaire, and electroencephalogram. SRS-18, blood pressure, questionnaire was performed before and after experiment. Electroencephalogram was continuously measured during whole experiment and used for emotional spectrum analysis method (ESAM) calculation. Experiment was divided into three conditions (initial normal condition, negative air ion boosted condition at middle concentration, after ventilated condition) and three phases (accommodation, rest, calculation) at each condition.<br>At young group, excessive negative air ions increased human psychological concentration which is calculated by ESAM. At calculation phase, psychological concentration has a positive correlation with psychological stress (correlation factor 0.505). Otherwise at old aged group, no significant change was observed. It shows that sensitivity of negative air ions at old persons will be reduced. It also suggests that human sensitivity for negative air ion decreases with aging.<br>At rest phase of young group in negative air ion boosted condition, elementary emotions are balanced at ESAM. This shows that balancing among four elementary emotions is related with psychological effects of negative air ions.