Biomedical subjects

B Galle

Publications and source records attributed to B Galle.

10 recordsLinked to original sources

PubMed2001

Measurements of methane emissions from landfills using a time correlation tracer method based on FTIR absorption spectroscopy.

Methane is an important climate gas contributing significantly to global warming. A large part of the anthropogenic emissions of methane comes from landfills. Due to the biogenic origin of these emissions and the inhomogeneous characteristics of landfills and their soil cover, these emissions show large spatial variation. Thus, development of reliable and cost-effective methods for measurements of these emissions is an important task and a challenge to the scientific community. Traditionally, field chamber methods have been used but also different area integrating methods based on downwind plume measurements. These measurements have been supported by meteorological data either directly from local measurements or by controlled release of tracer gas from the landfill providing the dispersion characteristics of the plume. In this paperwe describe a method,the Time Correlation Tracer method, combining controlled tracer gas release from the landfill with time-resolved concentration measurements downwind the landfill using FTIR absorption spectroscopy. The method has been tested and used on measurements at a landfill in southern Sweden over the past 1.5 years. The method has proven to be a usable method for measurements of total methane emission from landfills, and under favorable meteorological conditions we estimate an achievable accuracy of 15-30%. The real time analysis capability of the FTIR makes it possible to judge the success of the measurement already on site and to decide whether more measurements are necessary. The measurement strategy is relatively simple and straightforward, and one person can make a measurement from a medium sized landfill (1-4 ha) within a few days to a week depending on the meteorological situation.

Air Pollutants↗

PubMed2001

Microencapsulation of carbon particles used as oxygen sensors in EPR oximetry to stabilize their responsiveness to oxygen in vitro and in vivo.

The electron paramagnetic resonance (EPR) spectra of some paramagnetic materials exhibit a pO2 (partial pressure of oxygen)-dependent linewidth. By recording the EPR linewidth in vivo using low-frequency EPR spectrometers, it is possible to measure the partial pressure of oxygen in tissues. It has been found, however, that some of the paramagnetic materials with optimal spectroscopic properties in vitro may lose or change their responsiveness to oxygen in tissues. The aim of this study was to microencapsulate paramagnetic particles by biopolymers in order to stabilize their responsiveness to oxygen. Carbohydrate char particles (Bubinga) were encapsulated with different biopolymers: cellulose acetate or cellulose triacetate, silicone and polyurethane. The performance of the materials was evaluated in vitro and in vivo. X-band EPR spectroscopy was used to test the variation of the calibration curve (EPR linewidth as a function of the pO2) after incubation in saline and after prolonged residence in tissues. The stability of the responsiveness to PO2 in vivo was carried out by L-band EPR spectroscopy using mice that received injection of the oxygen sensors in the muscles. After residence in saline and prolonged residence in tissues, only the calibration curve of the silicone-coated (coating weight of 0.5% (w/w)) paramagnetic materials remained unchanged, while those of oxygen sensors coated with cellulose acetate, cellulose triacetate and polyurethane changed.

Animals↗

PubMed2001

Continuing medical education. What do Minnesota physicians want?

CONTEXT: Continuing medical education (CME) is necessary for ongoing licensure and is critical in maintaining professional expertise. However, educators may not always consider their students preferences when developing new programs. OBJECTIVE: To determine physician preference for the format of CME programs and to learn what factors contribute to selecting a CME activity. DESIGN: Survey with 12 multiple response items pertaining to educational objectives, past educational experiences, and demographic information. PARTICIPANTS: A total of 1,967 Minnesota physicians were sent the survey; 385 physicians returned surveys within 2 months of mailing date (20% return rate). RESULTS: The vast majority of respondents reported participating in traditional CME programs during the preceding two years, and most said they planned to attend a traditional program in the next two years. CONCLUSIONS: Minnesota physicians overwhelmingly prefer attending traditional CME programs to participating in more interactive, technology-based activities. Before new technology such as the Internet can be widely used in CME, it must be made attractive to the practicing physician.

Attitude of Health Personnel↗

PubMed2000

Assessment of terpene levels and workers' exposure in sawmills with Long Path FTIR.

This study focuses on the assessment of airbone terpene levels in the saw shed of a sawmill. It describes results and practical aspects concerning the indoor use of a Long Path FTIR measurement technique that was primarily developed for emission monitoring in outdoor applications. The results from FTIR sampling are compared with results from personal adsorbent samples and a point monitoring PID instrument. The Long Path FTIR light path covered the entire length of the saw shed in the mill. This enabled measurement of real-time, path integrated concentrations along the beam path. The four monoterpenes alpha-pinene, beta-pinene, delta 3-carene, and limonene were identified along with ethanol. Quantification was achieved by using a classical least square evaluation software. The limit of detection of the individual terpenes was 1.5 mg/m3, or 0.27 ppm. The terpene levels in the sawmill fluctuated significantly and the average concentrations exceeded the Swedish 8-hour PEL (150 mg/m3, 25 ppm). Peak levels were recorded near the Swedish short-term exposure limit (300 mg/m3, 50 ppm). Results from simultaneous sampling with personal adsorbents, analyzed by GC, showed good agreement with the long path FTIR sampling (r = 0.98, n = 7). The FTIR application described is general in nature and offers a stable and convenient form for continuous monitoring over extended periods of times, and the conclusions drawn from this study may well be applied in other similar surveys.

Air Pollutants, Occupational↗

PubMed1993

Prescribing for unlabeled indications.

Little is known about the practice of physicians prescribing drugs for unlabeled (off-label) indications (prescribing approved drugs for indications not listed/approved in the FDA New Drug Application). In order to learn more about this practice, a 17-item questionnaire was administered to 251 physicians, many of whom practiced in some form of managed care setting. Respondents were asked for which of several indications they would prescribe five specific drugs. Some of these indications were labeled (approved by the FDA) while others were not. In addition, respondents were asked to list drugs they thought were commonly used for unlabeled indications. Results indicated that 88% of the physicians used drugs for unlabeled indications. Nearly 25% prescribed off-label daily. Correlations between demographics and prescribing practices were conducted, and descriptive data on sources of information used for new drug uses are described. Efficacy and payment considerations make this subject important for policy and practice decisions.

Adult↗

PubMed1987