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Biomedical subjects

B C Stuart

Publications and source records attributed to B C Stuart.

7 recordsLinked to original sources
PubMed1997

Ablation of human nail by pulsed lasers.

BACKGROUND AND OBJECTIVE: The hard and resistant structure of the nail plate forms a natural barrier that limits the penetration of topical drugs. To overcome this barrier, the use of pulsed laser systems has been suggested. The purpose of this study was to evaluate the effect of four laser systems on nail plate ablation rates, ablation efficiencies, and subsequent craters morphology. STUDY DESIGN/MATERIAL AND METHODS: Solid state Er:YAG (2.94 microns, 250 microseconds), a Ho:YSGG (2.08 microns, 250 microseconds), a XeC1 Excimer (308 nm, 15 ns), and a novel solid-state ultrashort pulse laser (1.05 microns, 350 fs) were used. Ablation rates, surface morphology, and extent of collateral damage were evaluated using light and electron microscopy. RESULTS: Best ablation efficiencies were demonstrated with the ultrashort pulsed laser (1 micron/mJ), whereas maximum material removal per pulse was obtained with the Er:YAG laser (80 microns/ pulse). Scanning electron microscopy showed cracking damage with both Ho:YSGG and Er:YAG. XeC1 and the ultrashort pulse system left tissue surfaces free of cracks or thermal damage. CONCLUSION: With its minimal acoustical and mechanical impact, high efficiency, and negligible collateral damage, the ultrashort pulse laser at 3 J/cm2 was found to be the optimal laser system for nail ablation.

Humans↗
PubMed1994

Assessment and control of nonresponse bias in a survey of medicine use by the elderly.

Health services research based on survey data is subject to potentially serious selection bias because observations are typically available only for survey respondents. This study describes a method of assessing and controlling for selection bias in the context of a survey of prescription and over-the-counter drug use by the elderly. A random sample of 6,500 Pennsylvania Medicare enrollees was sent a questionnaire regarding medicine use, insurance coverage, and health status in 1990. Applying a two-stage, limited dependent variable selection model developed by Heckman to baseline Medicare enrollment and utilization data for both respondents (70%) and nonrespondents (30%) allowed us to detect and control for negative and significant nonresponse bias in estimates of prescription drug use. Purchase of over-the-counter medication was free of such bias. The report describes how the Heckman method can be applied in other cases where health services survey samples are generated from program or organizational files that contain person-level data on all members of the sample frame.

Age Factors↗
PubMed1987

A micro-computer based approach to curriculum evaluation.

The wide range of content appropriate to graduate study in health administration calls for an effective means to analyze the structure and content of the graduate program curriculum. This article presents a curriculum analysis matrix approach to curriculum evaluation. The matrix approach uses spreadsheet software to carry the analysis through several iterations, involving faculty throughout the process. A case illustration is presented. This approach is deemed relevant to accreditation self-studies and to any other periodic curriculum reviews.

Computers↗
PubMed1986

Reimbursement and access to physicians' services under Medicaid.

Several recent studies have shown that physician participation in state Medicaid programs is directly related to the generosity of their reimbursement levels. The implication is that when states reduce fees, Medicaid eligibles suffer because their access to physicians' services is thereby limited. The results presented in this paper do not support this implication. Multivariate analyses of utilization and site-of-visit patterns among non-elderly Medicaid eligibles indicate that stringent physician reimbursement practices do not impede access to ambulatory care when all sites at which a doctor may be seen are considered.

Adult↗