Marker Pen Device with Concentration Gradient Nib for Antibiotic Susceptibility Testing

BACKGROUND: Pen-based devices have emerged as useful tools for measuring pH and glucose, and for fabricating microchannels and microarrays. Pen-based devices take advantage of flexible patterning, inexpensive costs, and small volumes, thereby saving time and increasing efficiency. We have developed a gradient nib marker pen device that generated simultaneously different antibiotic concentrations in bacteria antibiotic susceptibility testing (AST). METHODS: The device can deposit on the target surface with the antibiotic gradient. The designed polyester fiber nibs are a highly uniform porosity with unidirectional orientation and produce a visible gradient pattern. RESULTS: We have demonstrated and quantitatively analyzed bacterial growth after antibiotic marking. The antibiotic marking produces an inhibition zone of bacterial growth. The inhibition zones of bacterial growth are captured and converted to 8-bit grayscale images, and then quantified by gray values using the Image J program. A profile of the inhibition zone showed different gray values in response to bacterial viability. CONCLUSION: The gradient nib marker pen device can be used to determine the quantitative antibiotic concentration based on the relationship between gray values and bacterial density conveniently without requiring a series of dilution tubes, including nutrient medium, and diversely diluted antibiotics.

Effects of Nutritional Education Program through Discretional Activities in Middle School Students

The effects of a nutritional education program for first grade middle school students were evaluated from August to December, 2006. The study subjects were 82 boys and 90 girls, residing in Gwangju, Korea. To assess the effects of the nutritional education program, pre- and post-questionnaires examining nutritional knowledge, dietary attitudes, and dietary habits were developed. Paired t-test and repeated measures ANOVA were used to evaluate the effects of the nutritional education program. In the general subject, the main after-school activities were studying, watching TV, and using computer (85.5%), and sports (9.3%), suggesting their low physical activity. Parents (46.5%) were indicated as the source of nutritional education rather than teachers (13.4%). Twenty-five percent of girl students had diet experience of skipping meals (54.6%), suggesting the need of proper nutritional education for adolescents' health care. In dietary attitudes, both genders showed some improvement of recognition after education. In the changes in dietary habits, both genders had a significant effect on 'three meals a day, eating breakfast, and regular meal' after education. After education, the rate of having breakfast everyday increased from 52.4% to 65.9% for boys and from 33.3%to 57.8% for girls. In the changes in nutritional knowledge, the appreciation of the importance of school meals increased in both genders from 50.6% to 80.8% after education. The nutritional knowledge, scores of regular eating and well-mannered eating increased in both genders regardless of the students' characteristics. The study results revealed that this education provided an important motivation to improve basic nutritional knowledge and dietary habit. It is recommended to develop systematic and various educational programs and learning materials tailored to subjects before nutritional education.

Pulp response of mineral trioxide aggregate, calcium sulfate or calcium hydroxide / 대한치과보존학회지

This study was performed to verify the possibility of MTA and calcium sulfate as a pulp capping agent through comparing the dental pulp response in dogs after capping with MTA, calcium sulfate, and calcium hydroxide. 24 teeth of 2 dogs, 8 month old, were used in this study. Under general anesthesia, cervical cavities were prepared and pulp was exposed with sterilized #2 round bur in a high speed handpiece. MTA, calcium hydroxide, and calcium sulfate were applied on the exposed pulp. Then the coronal openings were sealed with IRM and light-cured composite. Two months after treatment, the animals were sacrificed. The extracted teeth were fixed in 10% neutral-buffered formalin solution and were decalcified in formic acid-sodium citrate. They were prepared for histological examination in the usual manner. The sections were stained with haematoxylin and eosin. In MTA group, a hard tissue bridges formation and newly formed odontoblasts layer was observed. There was no sign of pulp inflammatory reaction in pulp tissue. In calcium hydroxide group, there was no odontoblast layer below the dentin bridge. In pulpal tissue, chronic inflammatory reaction with variable intensity and extension occurred in all samples. In calcium sulfate group, newly formed odontoblast layer was observed below the bridge. Mild chronic inflammation with a few neutrophil infiltrations was observed on pulp tissue. These results suggest that MTA is more biocompatible on pulp tissue than calcium hydroxide or calcium sulfate.