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At least 397 records · Page 22Linked to original sources
PubMed1995

Magnetically enhanced protection of bone marrow from beta particles emitted by bone-seeking radionuclides: theory of application.

Utilization of radiopharmaceuticals that directly target radioactivity to tumors for treatment has a great deal of promise. Ideally, lethal doses of radiation could be delivered precisely to areas of disease, while, for the most part, sparing normal tissues. This potential, however, has not yet been fully realized. Current limitations of this approach are low tumor uptake of radiopharmaceuticals and dose-limiting radiotoxicity. In an effort to offset low uptake, radionuclides that emit high average-energy electrons have been proposed. Unfortunately, use of these radionuclides increases myelosuppression on a per decay basis. In order to allow for the utilization of high doses of this class of high-energy beta emitters, we propose the application of a strong static homogeneous magnetic field to constrain the beta particles. Monte Carlo computer simulations indicate that application of a 10 T magnetic field can decrease the total radiation dose from bone-avid tracers to marrow located in shafts of human long bones by 14%. More significantly, however, the penetration depth of high-energy electrons from the bone surface into the marrow can be reduced by up to 74.6%. Preservation of marrow in areas distal to the bone has previously been shown to facilitate relatively rapid recovery from pancytopenia produced by radiation damage to trabecular marrow (without marrow transplantation). Magnetically enhanced protection of bone marrow, therefore, may allow administered doses of high-energy beta-emitting radionuclides to be increased. By raising the limits on injected quantities of such highly ionizing radionuclides, amounts of the radiation dose absorbed by both soft and calcified tissue tumors will be increased, compared to conventional treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta Particles↗
PubMed2006

Psychiatric nurses' perceptions of the constituents of the therapeutic relationship: a grounded theory study.

Psychiatric nursing is invariably linked with a therapeutic role; however, the question remains unanswered in relation to the extent psychiatric nurses perceive the importance of the constituents of the therapeutic relationship. The aim of this research is to ascertain the nature and comprehension psychiatric nurses assign the development of this therapeutic relationship. Grounded theory methodology was utilized to develop these conceptualizations to elicit a theory relating to what comprises the therapeutic relationship. Semi-structured depth interviews were conducted with 6 registered psychiatric nurses who have 2-10 years of experience. The main findings of the research related to how psychiatric nurses learn to form these relationships and what skills are utilized within the relationship. The research discovered that the therapeutic relationship is therapeutic, but the degree of positive change is difficult to measure. The results of the study indicate that the process of developing therapeutic relationships is a combination of a learned experience through the acquiring of interpersonal skills; however, these skills are redundant if the individual has not acquired sufficient life experience to intuitively appreciate the therapeutic aspect of the relationship.

Attitude of Health Personnel↗
PubMed2006

Autonomy and control: augmenting the validity of the theory of planned behaviour in predicting exercise.

This study examined the utility of the theory of planned behaviour (TPB) along with additional constructs in predicting exercise, and explored the motivational antecedents of exercise intentions. Participants included 162 Canadian University College students (61% females). Measures of TPB, autonomous and controlling intention, perceived autonomy support and core autonomous intention were completed during phase 1 of data collection. Two and three weeks later behaviour was assessed. Hierarchical regression analyses revealed that: (a) attitude and perceived behavioural control significantly predicted TPB intention and core autonomous intention; (b) subjective norm predicted controlling intention; and (c) perceived autonomy support predicted autonomous and core autonomous intention. TPB intention significantly predicted behaviour. TPB is a fairly useful model for predicting behaviour and important information can be gained when other measures of intention are explored.

Adult↗
PubMed2000

[Fuzzy space based segmentation algorithm on periosteum medical image processing].

Object description in medical image often has the property of fuzziness, and with the development of computing, fuzzy logical theories are progressively used in medical image processing. Color medical images differ in spacial presentation and fuzzy description from grey-scale images and must be analyzed by special methods. In this paper, a new method of bone cell segmentation based on fuzzy logical theories is presented. With the utilization of fuzzy set theories in the steps of color enhancing, feature extraction and automatical segmentation, bone cells are detected from the background. The method has the advantages of high accuracy and flexibility to many situations. Experiments of bone cell images have proved that it is a fast and effective method.

Algorithms↗
PubMed1993

Adolescent suicide and families: an ecological approach.

Suicide is an issue of increasing concern for professionals who work with adolescents and their families. Over the past three decades, the rate of suicide has increased dramatically among 15- to 24-year-olds and is the third leading cause of death in this age group. Previous theoretical approaches to understanding adolescent suicide (i.e., Durkheim's sociological theory of suicide, social learning theory, psychological theory, and family systems theory) are reviewed, and the utilization of human ecological theory is proposed. Factors associated with adolescent suicide at the organism (individual), microsystem, mesosystem, exosystem, and macrosystem levels are examined. Finally, examples of prevention and intervention at each level are presented.

Adolescent↗
PubMed1992

Practitioners' use of theory: examples from a workgroup.

There is a continuing discussion within the field of health education about the relationship between theory and practice. Much of this discussion, particularly that which appears in professional journals, has been developed by academicians and is prescriptive. That is, it identifies ways in which theory should be used by practitioners. The purpose of this article is to facilitate this ongoing discussion by providing descriptive information on how theory is used by a group of health educators who work for the same organization. This information is used as a springboard for discussion more generally about the nature of theory in health education. This article represents the thinking and experiences of a dozen health professionals, in reaction to the question. "How do you use theory in your practice?" The authors believe this information will be useful in helping theoreticians develop more useful theory and helping practitioners increase their understanding of the utility of good theory. The division between theory and practice in the field of health education represents a significant opportunity and challenge to the discipline if energy can be redirected from criticism of the other "camp" to effective collaboration and enhanced effectiveness of health education efforts.

Attitude of Health Personnel↗
PubMed1979

Adults' drug use: relationship to perceived drug use of parents, friends while growing up, and present friends.

Results from a random household survey of the Boston Standard Metropolitan Statistical Area show a consistent and relatively strong association of adults' use of coffee, tobacco, alcohol, tranquilizers, and marijuana with their perceptions of present friends' use. Associations with parents' and past adolescent friends' use are much weaker. The results support efforts to explain illicit drug use with general theories of behavior acquisition and cast doubt on the utility of deviance theories.

Adolescent↗
PubMedDate not supplied

Psychosocial factors associated with young elementary school children's intentions to consume legumes: a test of the theory of reasoned action.

OBJECTIVE: The purpose of this study was to test the utility of the Theory of Reasoned Action (TRA) in explaining young elementary school children's intention to consume legumes. METHODS: A survey was conducted with children in an urban, multicultural community in Massachusetts. A total of 336 children participated. Logistic regression analysis was used to assess the strength of the relationship between attitude and subjective norm and intention. RESULTS: Although attitude was significantly associated with intention, the pseudo-R2 for the regression model that included only the TRA constructs was extremely low (.01). Adding demographic factors and preference improved the model's predictive ability, but attitude was no longer significant. CONCLUSION: The results of this study do not provide support for the predictive utility of the TRA with young elementary school children for this behavior, when demographic factors are accounted for. Hedonic factors, rather than reasoned judgments, may help drive children's intentions.

Attitude↗
PubMed2006

Application of the vacancy solution theory to describe the enthalpic effects accompanying mixed-gas adsorption.

The possibility of utilizing vacancy solution theory (VST) to study the enthalpic effects accompanying mixed-gas adsorption equilibria is presented. Besides heterogeneity, the interaction effects by using the regular adsorbed solution, Flory-Huggins, and Wilson models of nonideality in the adsorbed phase are taken into account. To predict adsorption phase diagrams and calorimetric effects in the mixed-gas adsorption system, only a knowledge of the single-gas adsorption isotherms and accompanying calorimetric effects is required. The possibility of simplification of the obtained theoretical expressions is shown. The obtained agreement between theory and experiment is very satisfactory.

Journal Article↗
PubMed1999

A motivational message, external barriers, and mammography utilization.

Based on a theory of behavior, the interaction of a motivational message and external barriers on mammography utilization was tested. Participants (N = 101) had not had mammograms annually, and were identified from an urban clinic serving a disproportionally high percentage of indigent clients. Fifty-five percent were Caucasian; 45% were African-American. In an experimental design, half of the sample received a telephone discussion about rationale, feelings, and beliefs regarding mammograms, and half did not receive this contact. Four months later, nurses assessed women's recent mammography utilization and external barriers (e.g., affordability and accessibility). A logistic regression revealed an interaction between the intervention and barriers on postintervention mammography utilization (odds ratio: 2.12; p < 0.05). As proposed, the intervention was associated with a 64% rate of mammography utilization among women without barriers, but only a 26% rate among women with barriers. Not only should clinicians offer motivational messages about mammography, but also administrators should address external barriers to maximize mammography among socioeconomically disadvantaged groups.

Aged↗
PubMed2006

Benchmarking the performance of density functional theory based Green's function formalism utilizing different self-energy models in calculating electronic transmission through molecular systems.

Electronic transmission through a metal-molecule-metal system is calculated by employing a Green's function formalism in the scattering based scheme. Self-energy models representing the bulk and the potential bias are used to describe electron transport through the molecular system. Different self-energies can be defined by varying the partition between device and bulk regions of the metal-molecule-metal model system. In addition, the self-energies are calculated with different representations of the bulk through its Green's function. In this work, the dependence of the calculated transmission on varying the self-energy subspaces is benchmarked. The calculated transmission is monitored with respect to the different choices defining the self-energy model. In this report, we focus on one-dimensional model systems with electronic structures calculated at the density functional level of theory.

Journal Article↗
PubMedDate not supplied

Dissemination and utilization of health promotion and disease prevention knowledge: theory, research and experience.

We review the theoretical and research foundations of knowledge dissemination and utilization. We examine first the features that describe the typical pattern of the spread and adoption of ideas in populations. A second level of theory examines the forces that explain and predict the diffusion of health promotion and disease prevention knowledge and innovations in two spheres, the public sphere and te professional sphere. A third level of theory produces models to guide the planning and evaluation of dissemination efforts and advocacy for policies to support the application of knowledge. We trace major research traditions through the literature of various disciplines of professions that have studied diffusion. We then outline some key issues related to knowledge dissemination and utilization in the fields of health promotion and disease prevention.

Ethics, Professional↗
PubMed1999

Quantitative tools for comparing animal communication systems: information theory applied to bottlenose dolphin whistle repertoires.

Comparative analysis of nonhuman animal communication systems and their complexity, particularly in comparison to human language, has been generally hampered by both a lack of sufficiently extensive data sets and appropriate analytic tools. Information theory measures provide an important quantitative tool for examining and comparing communication systems across species. In this paper we use the original application of information theory, that of statistical examination of a communication system's structure and organization. As an example of the utility of information theory to the analysis of animal communication systems, we applied a series of information theory statistics to a statistically categorized set of bottlenose dolphin Tursiops truncatus, whistle vocalizations. First, we use the first-order entropic relation in a Zipf-type diagram (Zipf 1949 Human Behavior and the Principle of Least Effort) to illustrate the application of temporal statistics as comparative indicators of repertoire complexity, and as possible predictive indicators of acquisition/learning in animal vocal repertoires. Second, we illustrate the need for more extensive temporal data sets when examining the higher entropic orders, indicative of higher levels of internal informational structure, of such vocalizations, which could begin to allow the statistical reconstruction of repertoire organization. Third, we propose using 'communication capacity' as a measure of the degree of temporal structure and complexity of statistical correlation, represented by the values of entropic order, as an objective tool for interspecies comparison of communication complexity. In doing so, we introduce a new comparative measure, the slope of Shannon entropies, and illustrate how it potentially can be used to compare the organizational complexity of vocal repertoires across a diversity of species. Finally, we illustrate the nature and predictive application of these higher-order entropies using a preliminary sample of dolphin whistle vocalizations. The purpose of this preliminary report is to re-examine the original application of information theory to the field of animal communication, illustrate its potential utility as a comparative tool for examining the internal informational structure of animal vocal repertoires and their development, and discuss its relationship to behavioural ecology and evolutionary theory. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1995

The predictive capacity of the theory of reasoned action and the theory of planned behavior in exercise research: an integrated literature review.

Although the association between habitual exercise and health benefits has been well documented, physical activity levels in the United States are lower than is necessary to reach the nation's health potential. Beliefs that people hold can be a motivating factor in engaging in exercise. A critical review of the literature was conducted to assess the efficacy of using the Theory of Reasoned Action and the Theory of Planned Behavior with respect to exercise. Evidence for the predictive utility of the theories was found. The Theory of Planned Behavior is a more promising framework for the study of exercise because it includes beliefs about control of factors that would facilitate or inhibit carrying out exercise. Strategies for use of the theories in planning exercise programs are provided and suggestions for future research discussed.

Behavior↗
PubMed1995

A program plan addressing carpal tunnel syndrome: the utility of King's goal attainment theory.

1. Today's nurse is prepared to address the needs of groups of individuals who share common characteristics or risks (aggregates). Program planning skills and ability to use nursing theory can enhance the nurse's effectiveness in addressing the needs of such aggregates. 2. Carpal tunnel syndrome and other repetitive stress injuries are very costly to industry, both in terms of monetary loss and lost work hours. Such injuries can be reduced in the workplace through careful observation and communication of trends by the nurse. 3. The systems perspective of King's goal attainment theory guided the nurse in problem solving and facilitating the development of a workplace capable of responding to trends as they occur.

Carpal Tunnel Syndrome↗