Is Ablative Fractional CO2 Lasering Effective at Reducing the Appearance of Moderate to Severe Atrophic Acne Scars As Per Patient Reports?

Objective: Is ablative fractional CO2 lasering effective at reducing the appearance of moderate to severe atrophic acne scars? Study Design: Review of published articles including one randomized controlled trial with blinded response evaluation, one randomized split-faced clinical study and one clinical trial were used for this review and were selected based on their relevance to the clinical question. Data Source: The most recent trials examining ablative fractional CO2 lasering for the treatment of moderate to severe atrophic acne scars were found using PubMed. Outcome Measured: Patient reported reduction in the appearance of atrophic acne scars was the outcome measured. Results: Hedelund et al. demonstrated that postoperatively the laser treated skin appeared more even and smooth compared to untreated controlled sites. Patients were satisfied with treatments and satisfaction scores were similar at 1 month, 3 months and 6 months postoperatively p=0.117. Scar texture was evaluated by patients to be mild to moderately improved at 1 month, 3 months and 6 months postoperatively and the scores were not statistically different over time p=0.629. Qian et al. demonstrated that at 12 months after fractional CO2 laser treatment 12.9% of patients had an excellent response, while 38.71% showed a good to fair response. Zhang et al. demonstrated that both fractional CO2 laser treatment and fractional microplasma RF treatment had an equivalent effect. After treatment with fractional CO2 laser 60.6% of patients were very satisfied to satisfied, while after fractional microplasma RF laser treatment 66.7% of patients were very satisfied to satisfied. Conclusions: As per patient reports, atrophic acne scarring can be mildly to moderately improved with the use of ablative CO2 fractional laser treatment

Molecular dynamics of flows in the Knudsen regime

Novel technological applications often involve fluid flows in the Knudsen regime in which the mean free path is comparable to the system size. We use molecular dynamics simulations to study the transition between the dilute gas and the dense fluid regimes as the fluid density is increased.Comment: REVTeX, 15 pages, 4 EPS figures, to appear in Physica