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Biomedical subjects

S R Sutton

Publications and source records attributed to S R Sutton.

At least 19 recordsLinked to original sources
PubMed2006

Spatial and temporal variability of arsenic solid-state speciation in historically lead arsenate contaminated soils.

The arsenic (As) solid-state speciation (i.e., oxidation state, precipitates, and adsorption complexes) is one of the most important factors controlling dissolved As concentrations at As contaminated sites. In this case study, two representative subsurface samples (i.e., oxidized and semi-reduced sites) from former lead arsenate contaminated soils in the northeastern United States were chosen to investigate the effects of aging on As retention mechanisms using multiscale spectroscopic techniques. X-ray powder diffraction (XRD), synchrotron based microfocused (micro) XRD, in situ micro-synchrotron based X-ray fluorescence spectroscopy (SXRF), and micro-X-ray absorption near edge structure (XANES) spectroscopy were used to compliment the final bulk X-ray absorption spectroscopy (XAS) analyses. In the sample from an oxic area, As is predominantly (approximately 71%) present as As(V) adsorbed onto amorphous iron oxyhydroxides with a residue (approximately 29%) of an original contaminant, schultenite (PbHAsO4). Contrarily, there is no trace of schultenite in the sample from a semi-reduced area. Approximately 25% of the total As is present as adsorbed phases on amorphous iron oxyhydroxide and amorphous orpiment (As2S3). The rest of the fractions (approximately 46%) were identified as As(V)-Ca coprecipitates. This study shows that aging effects can significantly alter the original chemical constituent (schultenite) in soils, resulting in multi and site-specific As solid-state speciation. The variability in spatial and temporal scale may be important in assessing the environmental risk and in developing in situ remediation technologies.

Arsenates↗
PubMed2006

micro-XANES and micro-XRF investigations of metal binding mechanisms in biosolids.

Micro-X-ray fluorescence (micro-XRF) microprobe analysis and micro-X-ray absorption near-edge structure (micro-XANES) spectroscopy were employed to identify Fe and Mn phases and their association with selected metals in two biosolids (limed composted [LC] and Nu-Earth) before and after treatment to remove organic carbon (OC). Spatial correlations derived from elemental mapping of XRF images showed strong correlations between Fe and Cd, Cr, Pb, or Zn (r2= 0.65-0.92) before and after removal of most of the OC. The strong correlation between Fe and Cu that was present in intact samples disappeared after OC removal, suggesting that Cu was associated with OC coatings that may have been present on Fe compounds. Except for Fe and Cr, the spatial correlations of metals with Mn were improved after treatment to remove OC, indicating that the treatment may have altered more than the OC in the system. The Fe micro-XANES spectra of the intact biosolids sample showed that every point had varying mixtures of Fe(II and III) species and no two points were identical. The lack of uniformity in Fe species in the biosolids sample illustrates the complexity of the materials and the difficulty of studying biosolids using conventional analytical tools or chemical extraction techniques. Still, these microscopic observations provide independent information supporting the previous laboratory and field hypothesis that Fe compounds play a major role in retention of environmentally important trace elements in biosolids. This could be due to co-precipitation of the metals with Fe, adsorption of metals by Fe compounds, or a combination of both mechanisms.

Fluorescence↗
PubMed2006

How do patients who participate in cancer support groups differ from those who do not?

Research has shown that cancer patients in general benefit from support group participation. However, few patients attend such groups. This study investigated differences between participants of a community cancer support group and a random selection of non-participants from the Cancer Registry. Data were collected through mail survey, and included variables identified through past research and variables derived from Leventhal's self-regulatory model of illness representations and the theory of planned behaviour. Sixty-three support group participants and 44 comparison sample respondents were recruited. Support group participants were more likely to be female, without a partner, younger, and to have more education and formal support than non-participants. They held more favourable views of support groups, believed that significant others were favourable towards participation, and perceived less difficulty in joining a group. They furthermore used more active, adaptive coping strategies and felt more control over their cancer, but were more distressed and anxious. Non-participants reported more support from a special person. A multivariate logistic regression analysis showed only psychosocial variables to be independent predictors of participation. As psychological variables are amenable to change, increase of appropriate support group participation should be possible, for instance by addressing patients' beliefs about support groups.

Adaptation, Psychological↗
PubMed2001

Chromium diffusion and reduction in soil aggregates.

The distribution of metal contaminants such as chromium in soils can be strongly localized by transport limitations and redox gradients within soil aggregates. Measurements of Cr(VI) diffusion and reduction to Cr(III) were obtained in soil columns representing transects into soil aggregates in order to quantify influences of organic carbon (OC) and redox potentials on Cr transport distances and microbial community composition. Shifts in characteristic redox potentials, and the extent of Cr(VI) reduction to Cr(III) were related to OC availability. Depth profiles of Cr(VI, III) obtained with micro X-ray absorption near edge structure (micro-XANES) spectroscopy reflected interdependent effects of diffusion and spatially dependent redox potentials on reduction kinetics and microbial community composition. Shallow diffusion depths (2-10 mm) and very sharply terminated diffusion fronts in columns amended with OC (80 and 800 ppm) reflected rapid increases in Cr reduction kinetics over very short (mm) distances. These results suggest that Cr contamination in soils can be restricted to the outsides of soil aggregates due to localized transport and rapid reduction and that bulk sample characterization is inadequate for understanding the controlling biogeochemical processes.

Chromium↗
PubMed2000

Hospitalization in the Program of All-Inclusive Care for the Elderly (PACE): rates, concomitants, and predictors.

BACKGROUND: The Program of All-Inclusive Care for the Elderly (PACE) replicates the model of comprehensive, community-based geriatric care pioneered by On Lok, that enrolls frail older adults who meet states' criteria for nursing home care, and that uses interdisciplinary teams to assess the participants and to deliver care in appropriate settings. As managed care, PACE receives capitated payment from Medicare and Medicaid. Thus, PACE's fiscal incentives are thought to be aligned with the goals of optimizing health, function, and quality of life through the delivery of effective primary, preventive, restorative, supportive, and palliative care and through the avoidance of inappropriate and expensive hospital and nursing home utilization. OBJECTIVES: To describe short-term hospital utilization, hospital discharge diagnoses, time from enrollment to first hospitalization and its clinical predictors, and hospitalization in relation to mortality among PACE participants. METHODS: Data on short-term hospitalization and participants were recovered from PACE's minimum data set. Bed use was evaluated in annual cross-sections of current participants. Primary hospital discharge diagnoses were available for discharges from September 1, 1993 through March 31, 1997. The time from enrollment to hospitalization was calculated for the participants (n = 5478) who were admitted between January 1, 1990 and March 31, 1997. The characteristics of this inception cohort were used to develop a Cox regression model of hospitalization. All PACE deaths were identified and the place of death was recovered, together with the medical records used in the hospital during PACE enrollment or 6 months before death. RESULTS: Bed-days per 1,000 PACE participants per year were comparable with the general Medicare (fee-for-service) population, at 2,046 (in 1998) versus 2014 (in 1997) despite the greater morbidity and disability for PACE participants, as reflected in their enrollment characteristics and primary hospital discharge diagnoses. The time to hospitalization was 773 days (median); 95% confidence interval, 725, 814, and was predicted by disease, treatment, social and demographic factors. Whereas 8% of PACE deaths occurred in acute hospitals, less than one-third of the decedents spent any time in the hospital in the 6-month interval before death. CONCLUSIONS: Overall, short-term hospital utilization among PACE participants is low in contrast with that for other older and disabled populations. Participant predictors of hospitalization in PACE are generally consistent with other studies in older clinical and community populations. Both utilization and risk vary considerably across PACE sites, independent of participant-level risk factors, hence suggesting that further investigation is required to study PACE's management of acute illness and hospitalization decisions. Critical to maintaining PACE's success is an understanding of the independent impact of the organization and the environment of health care on this management.

Activities of Daily Living↗
PubMed1998

Stage theories of health behavior: conceptual and methodological issues.

Despite growing interest in stage theories of health behavior, there is considerable confusion in the literature concerning the essential characteristics of stage theories and the manner in which such theories should be tested. In this article, the 4 key characteristics of a stage theory-a category system, an ordering of categories, similar barriers to change within categories, and different barriers to change between categories--are discussed in detail. Examples of stage models of health behavior also are described. Four major types of research designs that might be used for testing stage theories are examined, including examples from the empirical literature. The most commonly used design, which involves cross-sectional comparisons of people believed to be in different stages, is shown to have only limited value for testing whether behavior change follows a stage process.

Attitude to Health↗
PubMed1995

Distribution of moderately volatile trace elements in fine-grained chondrule rims in the unequilibrated CO3 chondrite, ALH A77307.

The concentrations of Ni, Cu, Zn, Ga, Ge, and Se in five, fine-grained chondrule rims in the highly unequilibrated CO3 chondrite ALH A77307 (3.0) have been determined for the first time by synchrotron X-ray fluorescence (SXRF) microprobe at Brookhaven National Laboratory. These elements are especially useful for tracing the role of condensation and evaporation processes which occurred at moderate temperatures in the solar nebula. Understanding the distribution of moderately volatile elements between matrix and chondrules is extremely important for evaluating the different models for the volatile depletions in chondritic meteorites. The data show that the trace element chemistry of rims on different chondrules is remarkably similar, consistent with data obtained for the major and minor elements by electron microprobe. These results support the idea that rims are not genetically related to individual chondrules, but all sampled the same reservoir of homogeneously mixed dust. Of the trace elements analyzed, Zn and Ga show depletions relative to CI chondrite values, but in comparison with bulk CO chondrites all the elements are enriched by approximately 1.5 to 3.5 x CO. The abundance patterns for moderately volatile elements in ALH A77307 chondrule rims closely mimic those observed in the bulk chondrite, indicating that matrix is the major reservoir for these elements. The close matching of the patterns for the volatile depleted bulk chondrite and enriched matrix is especially striking for Na, which is anomalously depleted in ALH A77307 in comparison with average CO chondrite abundances. The depletion in Na is probably attributable to the effects of leaching in Antarctica. With the exception of Na, the volatile elements show a relatively smooth decrease in abundance as a function of condensation temperature, indicating that their behavior is largely controlled by their volatility.

Electron Probe Microanalysis↗
PubMed1991

Great expectations: some suggestions for applying the balanced placebo design to nicotine and smoking.

There are a number of methodological problems with the traditional placebo-controlled design used to investigate the effects of nicotine in human subjects. For example, the experimental instructions may create a 'guessing set' in the participants such that they search for possible clues to try to identify which condition they are in. If they guess correctly, the internal validity of the design may be threatened. Furthermore, by attempting to control for the effect of subjects' expectancies, the traditional placebo design precludes any estimate of expectancy effects. Continued use of this methodology in the smoking field is likely to lead to an overemphasis on pharmacological factors in smoking and a corresponding underemphasis on cognitive factors and nicotine-expectancy interactions. These problems can be overcome by the use of the balanced placebo design which orthogonally manipulates instructions (Told Nicotine versus Told Placebo) and nicotine (Received Nicotine versus Received Placebo). The balanced placebo design offers a powerful methodology for studying many aspects of smoking behaviour and nicotine effects, and three examples are given to illustrate its potential in this field: nicotine titration, nicotine and performance, and priming effects in smoking relapse.

Clinical Trials as Topic↗
PubMed1987

Experimental evaluation of the BBC TV series "So You Want To Stop Smoking?".

This paper reports a controlled evaluation of the six-part BBC TV series "So You Want To Stop Smoking?" which aimed to give advice and encouragement to smokers who wanted to stop. In an experimental design, 134 cigarette smokers in two firms were shown either the first two programs in the series or a control film of the same length. Smokers in the former group were asked to watch the remaining four programs at home on their own television sets. Questionnaires were sent to participants four months and one year later, and claims of abstinence were validated biochemically. The results did not provide clear evidence that the BBC series was more effective in encouraging smokers to try to stop and helping them to succeed than the control film. For comparison with our own results, we also abstract some findings from an uncontrolled but larger-scale evaluation conducted by the BBC's research department.

Adult↗
PubMed1985

Trying to stop smoking: effects of perceived addiction, attributions for failure, and expectancy of success.

This paper reports the results of a postal questionnaire completed by 2343 smokers who had contacted a television company for help with stopping smoking. Of these, 1848 (78.9%) completed a follow-up questionnaire 1 year later. This indicated that 797 had tried to stop, 709 had tried to cut down, and 164 had become abstinent. Analyses show that the intention to try to stop smoking was dependent not only on the perceived health benefit, but also on the subjects' confidence that they would succeed if they tried to stop. As predicted by Weiner's [(1979). J. Educ. Psychol. 71: 3-25] model of achievement motivation, those who attributed other smokers' failures at quitting to stable factors had lower expectancies of success, as had those who saw themselves as more addicted. When the follow-up data are considered, reported attempts at quitting were strongly related to previously declared intentions, and reported abstinence was related to previous confidence (expectancy of success) and perceived addiction. There is no support for hypotheses concerning self-other differences in attribution, or defensive attribution, in subjects' attributions for their own failures at cessation. Implications for antismoking interventions are discussed.

Adult↗
PubMed1984

The effect of fear-arousing communications on cigarette smoking: an expectancy-value approach.

This paper describes a model, derived from subjective expected utility ( SEU ) theory, which attempts to explain the effects of a fear-arousing communication about smoking and lung cancer on smokers' decisions to try to stop smoking. According to the model, the strength of the smoker's intention to try to stop smoking will depend on three factors: (1) the utility of lung cancer; (2) the perceived reduction in the risk of getting lung cancer that follows from successfully stopping smoking (probability difference); and (3) the subjective probability of successfully stopping smoking, or confidence. The usefulness of this model vis-á-vis one based on the amount of fear aroused by the communication was investigated in two experimental studies conducted in the field in which smokers watched either a videotape about smoking or one on a different health topic. The smoking videotape influenced not only attitudes and beliefs measured immediately after exposure but also subsequent self-reports of behavior (whether or not the subject tried to stop smoking or to cut down in the 3-month period following exposure to the videotape). In accordance with predictions, the three variables specified by the model together affected intention to try to stop smoking, which in turn affected behavior. The effect of confidence on intention was relatively large. There was no evidence for the multiplicative combination of utilities and subjective probabilities predicted by a strict SEU model. Contrary to the predictions of the model, but consistent with previous research, the amount of fear aroused by the videotape had an independent effect on intention, suggesting that explanations of the effects of fear-arousing communications will have to incorporate both cognitive and emotional mediation processes.

Cognition↗
PubMed1980

Smokers' response to shortened cigarettes: dose reduction without dilution of tobacco smoke.

This study was designed to examine the response of smokers to shortening their usual brand of cigarettes. The shortening reduces the dose of smoke available from each cigarette without affecting concentration and therefore differs from dose reduction by dilution, which occurs when smokers switch to cigarettes with lower tar and nicotine deliveries. Measures of smoking behavior (e.g., cigarette consumption, puff rate), mouth-level nicotine intake (calculated from butt content), and intake to the lungs (plasma nicotine and COHb) were made in 10 smokers after 48 hr ad libitum smoking of full, three-quarter, and half-length cigarettes in a Latin square design. Mouth-level smoke intake was maintained on shortened cigarettes due to a combination of 2 types of compensatory maneuver: (1) by increasing the intensity of puffing and thereby extracting proportionately more of the smoke available from each cigarette and (2) by smoking more cigarettes. The amount of smoke inhaled, on the other hand, was only partially maintained (58% compensation). This was achieved by increase in cigarette consumption alone. There was achieved by increase in cigarette consumption alone. There was no evidence of any compensatory increase in the amount of smoke inhaled from each cigarette. Increase in consumption was thus the only maneuver that contributed to maintaining smoke intake at lung level; mouth-level intake was regulated by increasing intake per cigarette as well as consumption.

Adult↗