The purposes of this study were to evaluate the effects on cell growth and migration of fibroblasts derived from human dental pulp by lasers using three-dimensional (3-D) cell culture system, and to compare the results with those from conventional methods using a two-dimensional (2-D) cell culture system. After extirpation from twenty freshly extracted human third molars showing no clinical sign of caries, pulp tissues were cultured in Minimum Essential Medium using a conventional 2-D cell culture. The cells between 5 and 18 passages were used for this experiment, and collagen gel (1 mg/ml) was used for the 3-D cell culture system. The energy densities used were 0.52 and 1.04 J/cm2 for the gallium aluminum arsenide (GaA1As) diode laser emitting at 830 nm, and 0.1 and 1.0 J/cm2 for the argon (Ar)-dye laser emitting at 632 nm. After laser irradiation, cells were counted at 2, 4, 6, and 8 days, and observed at 3 days by stereomicroscopy. There was no significant difference in cell count between the control groups and the laser-irradiated groups (both lasers) on any day using the 2-D cell culture system (p > 0.01). However, there were significant differences in cell count between the control groups and the laser-irradiated groups (both lasers) at 8 days using the 3-D cell culture (p < 0.01). Cell migration appeared more accelerated by laser in 3-D cell culture than in the 2-D system. These results suggest that the 3-D cell culture system is useful for the evaluation of potential stimulative effects of lasers.

Okra germplasm collected from different locations around the world were screened at AVRDC(The World Vegetable Center) in 2011 and 2012 to identify germplasm resistant to the melon aphid (Aphis gossypii) for use in sub-Saharan Africa. A total of 260 okra accessions and varieties were screened (150 at AVRDC Taiwan and 110 at AVRDC Cameroon), which included four varieties commercially available in Cameroon. The experiments were conducted under natural infestation in Shanhua, Taiwan, and at Yaoundé, Cameroon. Since the preliminary screening trials were conducted in Taiwan and Cameroon, the aphid populations in these two countries were compared. A total of 60 insects was used for cytochrome c oxidase I (COI) gene sequencing and phylogenetic analysis. The nucleotide sequences of all the populations showed 100 % similarity and the phylogenetic analysis confirmed the genetic similarity of A. gossypii in Taiwan and Cameroon. Results of the screening trials showed that three accessions (VI033805, VI036213 and VI051114) were resistant to A. gossypii. The basis of resistance of the three okra accessions was elucidated by studying their biochemical and biophysical properties. There was no significant difference between the susceptible and resistant okra accessions in terms of leaf tannins, free amino acids, total sugars and total phenols. Only total nitrogen was significantly different between the susceptible and the two resistant okra accessions with the lowest aphid infestation (VI033805 and VI036213). Thus, higher leaf nitrogen content seems to favour the aphid infestation on okra. For physical parameters, there was no significant difference among the accessions in trichome density of bottom and middle leaves, and leaf toughness. However, trichome density in the younger leaves of resistant VI033805 was significantly higher than susceptible VI057245. Studies on settling behaviour showed that aphids did not discriminate between the susceptible and resistant okra accessions for oviposition and feeding 72 h after release.