Objective: To test the hypothesis that picosecond laser pulses are more effective than nanosecond domain pulses in clearing of tattoos.Design: Intratattoo comparison trial of 2 laser treatment modalities.Setting: A large interdisciplinary biomedical laser laboratory on the campus of a tertiary medical center.Patients: Consecutive patients with black tattoos were enrolled; all 16 patients completed the study.Intervention: We treated designated parts of the same tattoo with 35-picosecond and 10-nanosecond pulses from 2 neodymium:YAG lasers. Patients received a total of 4 treatments at 4-week intervals. All laser pulse parameters were held constant except pulse duration. Radiation exposure was 0.65 J/cm 2 at the skin surface. Biopsies were performed for routine microscopic and electron microscopic analysis at the initial treatment session and 4 weeks after the final treatment in 8 consenting patients. Also, ink samples were irradiated in vitro. Main Outcome Measures:In vivo, on the completion of treatment, a panel of dermatologists not associ-

We studied transient cavitation bubble formation and acoustic emission around individual laser-heated microparticles using subnanosecond time-resolved microscopy. Microcavitation bubbles were observed as early as 0.5 ns after the particles were heated by a 30 ps laser pulse. The bubbles expanded to a few micrometers in size and collapsed on the time scale of 0.1–1 μsec. We discuss microcavitation as the origin of anomalously large photoacoustic effects and nonlinear optical responses observed in laser-heated colloidal suspensions, as well as a mechanism for cellular damage in biologic tissue containing pigment particles.

This study assessed the medication administration practices of school nurses. From a random sample of 1,000 members of the National Association of School Nurses, 649 (64.9%) completed the survey developed for the study. These school nurses report that during a typical day, 5.6% of children receive medication in school, with 3.3% receiving medications for ADHD. Almost all the school nurses follow written guidelines for administering medication. Potential problems were identified in documenting side effects of medications, storage of medications, student self-administration practices, and appropriate authorization of nonprescription drug use. Most nurses (75.6%) delegate medication administration to unlicensed assistive personnel (UAP), with secretaries (66.2%) the most common UAP. Discomfort with delegation and confusion over state nurse practice laws were noted. Errors in administering medications were reported by 48.5% of the school nurses, with missed dose (79.7%) the most common error. Factors identified as contributing to errors included use of UAP and responsibility for large numbers of students.

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