Effects of Wood Density on Aquatic Insect Communities in a Cuban Montane Rainforest Stream.

We tested whether hardness or different wood carbon densities, considered as the concentration of carbon structural compounds, influence functional feeding groups and species richness of aquatic insects in a tropical stream. We expected that harder woods would harbor aquatic insect communities with species richness and functional food group profile different from softwoods. We also expected that collector-gatherers and collector-filterers will be more abundant in softwood because harder woods are less substrate suitable for biofilm production. Aquatic insects associated with the following plants were analyzed: Gomidesia lindeniana with high-density, Psychotria grandis with medium-density, and Meriania leucantha with low-density wood. Diptera and Ephemeroptera were the most abundant groups sampled in the woods. Psychotria grandis shows higher concentrations of lignin, cellulose, and hemicellulose, followed by G. lindeniana and M. leucantha. Breakdown rates are different among plant species with M. leucantha having four times highest breakdown rates and on average three more species in the species richness value. We did not find significant differences in the composition of insect species associated with the plants. We found evidence that the richness and functional organization of aquatic insect communities were mostly related to the breakdown rates and lignin amount of the woods. Plants that decompose faster on average have three more species and two more insect functional groups. Our findings suggest that the loss of high carbon density trees in tropical forests can affect aquatic biodiversity.

Prospective study of hair reduction by diode laser (800 nm) with long-term follow-up.

BACKGROUND: Multiple laser systems are available for the purpose of hair removal. OBJECTIVE: The purpose of this study was to determine the safety and long-term efficacy of the 800 nm, pulsed diode laser at reducing hair count. METHODS: Fifty volunteers, primarily Fitzpatrick skin types II and III, with dark brown or black hair, were treated with a diode laser (800 nm, 10-40 J/cm2, 5-30 msec, 9 mm 9 mm, 5 degrees C chilled handpiece). Each subject had eight treatment sites at varying fluences and pulse durations, as well as a varying number of treatments and pulses. Hair counts were obtained at each site at baseline, 1, 3, 6, 9, and an average of 20 months after treatment. RESULTS: After one treatment, hair regrowths ranged from 22 to 31% at the 1-month follow-up visit, then remained stable between 65 and 75% from the 3-month to the averaged 20-month follow-up. After two treatments there were relatively longer growth delays, with hair regrowths plateauing beginning at 6 months after treatment and ranging from 47 to 66% for the remainder of the follow-up evaluations. Side effects were limited to pigmentary changes, transient in subjects with skin types II and III. CONCLUSIONS: This 800 nm diode laser with a chilled sapphire tip and variable pulse duration is safe and effective for long-term hair reduction in individuals with skin types II and III.

Effects of topical vitamin K and retinol on laser-induced purpura on nonlesional skin.

BACKGROUND: Pulsed dye laser treatments usually result in purpura. Any topical application that eliminates or shortens the duration of purpura would be extremely useful. OBJECTIVE: The purpose of this prospective study was to determine the safety and efficacy of topical vitamin K cream in shortening the duration of laser-induced purpura. METHODS: Twenty adult subjects were enrolled. Each subject had five 1.5 cm sites treated with a pulsed dye laser at 585 nm, 450 nsec, 7 mm spot size at each subject's respective threshold fluence. Each subject had a control site where no topical application was used and four other sites where a different formulation was applied to each for 2 weeks before and for 2 weeks after laser irradiation. Five vitamin K formulations with or without retinol were studied: 3% vitamin K in acrylates copolymer cream, 5% vitamin K in acrylates copolymer cream, 1% vitamin K and 0.3% retinol in acrylates copolymer cream, 1% vitamin K and 0.15% retinol in acrylates copolymer cream, 1% free vitamin K cream. Purpuric discoloration at each site was rated on days 0, 1, 3, 7, 10, and 14 after laser treatment on a quartile scale. Each site was assigned 100% discoloration on day 0 after laser irradiation. RESULTS: Laser-induced purpuric discoloration resolved faster with 1% vitamin K and 0.3% retinol in acrylates copolymer cream than with no topical application. The difference is statistically significant from day 3 onward. CONCLUSION: A combination of 1% vitamin K and 0.3% retinol in acrylates copolymer cream hastened the resolution of laser-induced purpura.