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The use of exhaled breath as a biological monitoring tool is still not widely used. Although there are now commercially available kits, there are limited data on biological guidance values for all but a few substances for breath monitoring. The study investigated the possibility of using an indirect breath sampler to measure the levels of nitrous oxide in the exhaled breath of midwives at a midpoint during their shift. Levels of nitrous oxide in file exhaled breath were measured at (0-727 ppm) with a mean level of 64 ppm. The correlation between the established personal environmental monitoring and exhaled breath monitoring was generally poor as was the correlation between duration of nitrous oxide exposure and levels in the exhaled breath. Clearly the use of exhaled breath as a tool for biological monitoring is more appropriate than other invasive procedures. The breath sampler used has been a readily acceptable tool for occupational hygiene monitoring in a busy hospital ward. [ABSTRACT FROM AUTHOR]

Discusses the gas dynamics of ethylene oxide (EO) during sterilization using a microwave spectrometer. Description of gas penetration, gas sorption and chemical reaction processes by diffusion equation; Effect of load density on gas penetration; Tendency of polymeric materials to absorb more EO.

Reports on the update in the design of a microwave spectrometer for measuring concentrations of ethylene oxide gas during sterilization. Specificity of the measurement using the spectrometer; Accuracy of the spectrometer; Interpretation of real time measurement data during sterilization.

Reports quantitative measurement of concentrations of water vapor and ethylene oxide in different gas mixtures by means of microwave spectrometer. Problem of absorption line broadening; Gas memory problem inherent in the quantitative analysis of gases; Calibration of ethylene oxide.

Reports on a microwave spectrometer with a novel technique of locking a frequency 'scanning window' in the radiation source to a microwave rotation absorption peak. Locking of the center of the scanning window to the resonant frequency; Input of microwaves to a resonant gas cell containing the analyte gas.

This paper reports a novel modulation technique, namely, cavity modulation coupled with asynchronous source modulation, employed in a simple microwave cavity spectrometer system. The feasibility of the technique was successfully demonstrated by determining the output of the system whilst examining one of the absorption peaks of ethylene oxide gas (with centre frequency F0 = 24.923 GHz for the level transition 202 to 211). The variation in the output signal with frequency was as expected to within a standard error of 8.3%. Also, a good linear correlation was demonstrated between the magnitude of the output signal and the concentration of ethylene oxide gas in the gas cell (to within a standard error of 4%). The operation of this system is such that the microwave source frequency, F, sweeps across a given range (F1 to F2) which contains one of the absorption peaks of the analyte gas whilst the cavity resonant frequency, Fr, is oscillated within the profile of the absorption peak. Signal enhancement is achieved by adding a relatively small magnitude high-frequency 'dither' signal to the source frequency sweep pattern. The salient information of the gas absorption due to the oscillation of the resonant frequency of the cavity is carried by the 'dither' signal and then amplified and extracted by a series of tuned amplifiers and demodulators. [ABSTRACT FROM PUBLISHER]

Background: During the influenza outbreak of 1999/2000, in the United Kingdom between weeks 49/99 and 06/00. We set out to prospectively recruit all adult patients with respiratory symptoms admitted to the largest non-teaching hospital in the country. Methods: All patients 18 years and older admitted with acute respiratory symptoms to a large district general hospital, serving a population of 190,000, during a period of influenza activity, were seen and if they fulfilled the case definition criteria for the study were recruited. Details were recorded of their age, chronic disease status, smoking behaviour, alcohol consumption, influenza and pneumococcal vaccination status. Each was matched with community controls for family physician, age, sex, socio-economic and chronic disease status. In addition, the study generated a 2:1 pool of unmatched controls to cases. Using case-control methodology, we set out to estimate the clinical effectiveness of influenza vaccination in preventing hospitalisation and the risks associated with chronic disease, alcohol consumption, smoking behaviour and previous hospitalisation. Presented here are the results for the matched subjects. Results: 346 cases were recruited, 89% with pre-existing chronic disease, matched community controls were found for 326 (95%). In total, the study generated 725 unmatched controls. Matched pair analysis revealed that vaccination protects against hospitalisation with an Odds Ratio of 0.38 (95% CI 0.25 to 0.51) indicating a strong protective effect, giving vaccine effectiveness of 62±13% in preventing hospitalisations. Overwhelmingly previous hospitalisation for respiratory disease (OR 7.6) contributed the greatest risk of being hospitalised with influenza, yet only 33% of cases in recommended groups received vaccination. Conclusions: This study has advantages over some other studies and again shows the benefits of vaccination and reinforces the contribution chronic ill health contributes to the complications of influenza infection and the missed opportunities for protection. [Copyright &y& Elsevier]

Background: This paper describes the personal and societal impact of a small outbreak of influenza in the United Kingdom over the winter 1999/2000. Methods: All adults hospitalised with acute respiratory symptoms were recruited into a case control study to examine the effectiveness of the influenza vaccination. All patients were admitted to a large district general hospital, serving a population of 190,000. Details were recorded of age, chronic disease, smoking behaviour, alcohol consumption, influenza and pneumococcal vaccination status. While in hospital, utilisation of hospital facilities, length of stay, use of critical care facilities and fatality were recorded. Clinical specimens were taken for serology and chest X-ray findings recorded. These individuals and community controls were followed up for an addition 2 years to compare their pre- and post-influenza morbidity and health-seeking behaviour. Results: Case recruitment occurred from week 51/99 to week 5/00 when influenza was circulating in the community. A total of 186 women and 160 men were recruited with an average age of 68.6 years. Eighty-nine percent had pre-existing chronic disease, stayed on average at least 10 days, the length of stay increasing dramatically with extreme age; 11% of the cases received intensive or critical care during the admission and, overall, the case fatality rate was 15%, 23% in the over-65 age group while hospitalised. Only 33% of the patients with pre-existing chronic disease received the influenza vaccination and only 21% pneumococcal. Follow-up of cases over a further 2 years showed that 94 (28%) had died compared to 25 (3.8%) of the matched controls. They suffered an increased number of hospital admissions, poorer heath and increased morbidity and mortality. Conclusions: Even small outbreaks of influenza have a profound impact on the lives of individuals and society. This study reinforces the need for increased efforts to improve vaccine uptake in those most at risk and the consequences for not taking such action. [Copyright &y& Elsevier]

Abstract: The first part of this paper presents a review of the problems that constrain the reliability of radiocarbon-based age models with particular focus on those used to underpin marine records. The reasons why radiocarbon data-sets need to be much more comprehensive than has been the norm hitherto, and why age models should be based on calibrated data only, are outlined. The complexity of the probability structure of calibrated radiocarbon data and the advantages of a Bayesian statistical approach for constructing calibrated age models are illustrated. The second part of the paper tests the potential for reducing the uncertainties that constrain radiocarbon-based age models using tephrostratigraphy. Fine (distal) ash layers of Holocene age preserved in Adriatic prodelta sediments are analysed geochemically and compared to tephras preserved in the Lago Grande di Monticchio site in southern Italy. The Monticchio tephras have been dated both by radiocarbon and varve chronology. The importance of basing such comparisons on standardised geochemical and robust statistical procedures is stressed. In this instance, both the Adriatic and Monticchio geochemical measurements are based on wavelength dispersive spectrometry, while discriminant function analysis is employed for statistical comparisons. Using this approach, the ages of some of the Adriatic marine ash layers could be estimated in Monticchio varve years, circumventing some of the uncertainty of radiocarbon-based age models introduced by marine reservoir effects. Fine (distal) ash layers are more widespread and better preserved in Mediterranean marine sequences than realised hitherto and may offer much wider potential for refining the dating and correlation of Mediterranean marine sequences as well as marine-land correlations. [Copyright &y& Elsevier]