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Biomedical subjects

M D Feit

Publications and source records attributed to M D Feit.

12 recordsLinked to original sources
PubMed2005

Radiation produced by femtosecond laser-plasma interaction during dielectric breakdown.

Optical breakdown by femtosecond and nanosecond laser pulses in transparent dielectrics produces an ionized region of dense plasma confined within the bulk of the material. This ionized region is responsible for broadband radiation that accompanies the breakdown process. Spectroscopic measurements of the accompanying light have been used to show that, depending on the laser parameters, the spectra may originate from plasma-induced second-harmonic generation, supercontinuum generation, or thermal emission by the plasma. By monitoring the emission from the ionized region, one can ascertain the predominant breakdown mechanism and the morphology of the damage region.

Journal Article↗
PubMed2004

Localized dynamics during laser-induced damage in optical materials.

Laser-induced damage in wide band-gap optical materials is the result of material modifications arising from extreme conditions occurring during this process. The material absorbs energy from the laser pulse and produces an ionized region that gives rise to broadband emission. By performing a time-resolved investigation of this emission, we demonstrate both that it is blackbody in nature and that it provides the first direct measurement of the localized temperature of the material during and following laser damage initiation for various optical materials. For excitation using nanosecond laser pulses, the plasma, when confined in the bulk, is in thermal equilibrium with the lattice. These results allow for a detailed characterization of temperature, pressure, and electron densities occurring during laser-induced damage.

Journal Article↗
PubMed2001

Influence of pulse duration on ultrashort laser pulse ablation of biological tissues.

Ablation characteristics of ultrashort laser pulses were investigated for pulse durations in the range of 130 fs-10 ps. Tissue samples used in the study were dental hard tissue (dentin) and water. We observed differences in ablation crater morphology for craters generated with pulse durations in the 130 fs-1 ps and the 5 ps-10 ps range. For the water experiment, the surface ablation and subsequent propagation of stress waves were monitored using Mach-Zehnder interferometry. For 130 fs-1 ps, energy is deposited on the surface while for longer pulses the beam penetrates into the sample. Both studies indicate that a transition occurs between 1 and 5 ps.

Differential Threshold↗
PubMed2001

A life cycle model of public policy issues in health care: the importance of strategic issues management.

Public policy affects health and social services organizations. Senior management has a responsibility to prevent inappropriate demands of stakeholders from predominating and to influence the outcome of public policy to the benefit of their organization through the strategic issues management process. This article presents a public policy issue life cycle model, life-cycle stages and suggested strategies, paths issues can take in the life cycle, and factors that affect issue paths. An understanding of these dynamics can aid senior managers in shaping and changing public policy issues and lessening external environment threats to their organization.

Decision Making, Organizational↗
PubMed1999

Screening of substance abuse in public welfare and child protective service clients: a comparative study of rapid assessment instruments vs. the SASSI.

In light of new welfare reforms, it is essential that public welfare workers move individuals from welfare to work in an expedient fashion. Client alcohol and/or drug use/abuse is one barrier that may inhibit this process. The following study (N = 93) administered both the Hudson Index of Alcohol Involvement, the Hudson Index of Drug Involvement (rapid assessment instruments) and the Miller Substance Abuse Subtly Screening Inventory (SASSI) to public welfare and Child Protection system clients. Results indicated that the two rapid assessment measures strongly correlated with the advanced, commonly used SASSI measure. It is suggested that public welfare workers should institute these rapid assessment instruments at intake to screen clients for alcohol and drug use/abuse. When indicated, the client could then be referred to the appropriate agency for further assessment and treatment, to better prepare them for employment as mandated by new welfare reforms. The rapid assessment instruments were found to be shorter than the SASSI, easily administered, and able to detect alcohol and/or drug use/abuse effectively and efficiently in these populations.

Adult↗
PubMed1990

A proposed cost effectiveness method for use in policy formulation in human service organizations.

This article builds on a previous publication and presents additional information on how cost effectiveness analysis may be used by policy and decision-makers in human service organizations (HSO's). It presents a brief history of the use of cost effectiveness analysis to demonstrate its efficacy in assisting policy makers in a variety of fields. It then comparatively describes two of the best known cost effective methods--cost benefit analysis (CBA) and cost effective analysis (CEA), and argues that the latter is the more appropriate method to be used to effect policy decisions in HSO's. The discussion centres around refining the limitations of the CEA method and proposes a simple model for use in this regard. Recommendations and implications are directed toward managers, administrators and decision-makers of HSO's. Finally, the article is attempting to fill a distinct void in the literature in this field and also suggests the use of more meaningful policy formulation and analyses methods in HSO's.

Cost-Benefit Analysis↗
PubMed1989

Using cost-effectiveness analysis in policy formulation in human service organizations.

This article describes how decision-makers may use a relatively simple cost-effectiveness analysis (CEA) method in policy formulation in human service organizations. The main contention of this article is that decision-makers need to know how to better effect policy decisions based on quantitative data. CEA is a decision-making tool which has been used sparingly in human service organizations, even though it is considered to be extremely useful in developing rational, cost-effective programs for the future. The paper describes the CEA model in a sequential step-by-step fashion and discusses its analytic processes and how it measures the costs and effects of human service programs. The conclusions and recommendations are targeted at decision-makers in human service organizations and stress the importance of obtaining accurate, reliable and useful cost-effectiveness data.

Cost-Benefit Analysis↗
PubMedDate not supplied

An analysis of federal narcotic detoxification policy: implications for rehabilitation.

The current federal narcotic detoxification policy, limiting such treatment to 21 d, is analyzed with respect to its impact on the success rate for complete withdrawal. Data are drawn from an historical review of American Medical Association statements on narcotic addiction and a review of empirical data on short- and long-term detoxification. The 3-week limit is shown to interfere with achieving successful detoxification rates, although it continues to guide federal detoxification policy. Empirical evidence supports long-term detoxification that recognizes other factors as also having a therapeutic effect. It is time to revise the current federal policy to more accurately reflect the progress made in long-term care.

Drug and Narcotic Control↗