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PubMed2001

Sliding drops in the diffuse interface model coupled to hydrodynamics.

Using a film thickness evolution equation derived recently combining long-wave approximation and diffuse interface theory [L. M. Pismen and Y. Pomeau, Phys. Rev. E 62, 2480 (2000)] we study one-dimensional surface profiles for a thin film on an inclined plane. We discuss stationary flat film and periodic solutions including their linear stability. Flat sliding drops are identified as universal profiles, whose main properties do not depend on mean film thickness. The flat drops are analyzed in detail, especially how their velocity, advancing and receding dynamic contact angles and plateau thicknesses depend on the inclination of the plane. A study of nonuniversal drops shows the existence of a dynamical wetting transition with hysteresis between droplike solutions and a flat film with small amplitude nonlinear waves.

Journal Article↗
PubMed1991

Promoting comprehensive school health programs through summer health promotion conferences.

This study reports on the evaluation of the second North Carolina Healthful Living Institute (HLI), a statewide conference to promote comprehensive school health education. A comparison of year one and year two evaluation results is included. Based on a theoretical framework derived from the theory of diffusion of innovations within organizations, the impact of the HLI was assessed by studying characteristics of school districts sending representatives to the HLI and the composition of teams from each school district, and using pretest and posttest measures of participants' perceptions of the importance of health as a content area and participants' perceptions of the importance of the various components of comprehensive school health. Results indicate the effect of school health promotion conferences is linked to characteristics of school district teams, with the Institute needing to attract more varied teams, and teams from smaller, rural districts.

Adult↗
PubMed1978

Synaptic delay in the heart: an ionophoretic study.

1. Neurotransmitters were applied ionophoretically to spontaneously beating clusters of ventricular muscle cells cultured from neonatal rats. 2. Acetylcholine or its analogue carbachol produced hyperpolarization and decreased the rate of spontaneous beating. These responses had minimum latencies of about 250 msec and total durations of 6-12 sec. 3. Noradrenaline, adrenaline or isoprenaline increased the rate of spontaneous beating. The minimum latency for this effect was 3-6 sec. Following a single brief pulse the rate remained elevated for 2 min or more. 4. Chronotropic responses of intact atria from adult rats to stimulation of the autonomic nerves were of similar time course to responses of the cultured muscle cells. 5. Calculations based on the theory of diffusion showed that access of drugs to their receptors could not be rate-limiting for the observed responses, unless a diffusion barrier of rather special properties was postulated. A number of other explanations for the long latencies have been ruled out; these are most likely to be due to some physical or chemical process occurring in or under the cell membrane. 6. Attempts to mimic responses to catecholamines by intracellular application of cyclic AMP were unsuccessful, perhaps because the release of nucleotide from the pipettes was insufficient. A theoretical treatment suggests that ionophoretic efflux of anions might be greatly diminished by the opposing electro-osmotic flux.

Acetylcholine↗
PubMed1996

Effect of macroscopic deformation on lung microstructure.

Using an anisotropic theory of diffuse light scattering in lungs, we measured the fractional changes in geometric mean linear intercepts in orthogonal directions when freshly excised rabbit lungs were subjected to isovolume uniaxial strains. Results from the optical technique were compared with morphometric estimates of fractional changes in mean linear intercepts from the same strained and unstrained (control) lobes, with the conclusion that diffuse light scattering is adequate to estimate changes in mean free paths in different directions. We compared optical estimates of fractional changes in mean linear intercepts with the macroscopic strain field measured by displacements of pleural markers; this relationship did not significantly differ from the line of identity. We conclude that the microscopic strain field is closely matched to the macroscopic strain field during uniaxial distortion. This suggests that surface reorientation may not play a large role in the origin of the low shear modulus of the lung, but this cannot be definitively stated without comparison of these experimental results to specific model predictions of the changes in mean linear intercepts in shear deformation.

Animals↗
PubMed1993

Effect on single-breath washout and lung function of elastase-induced emphysema in rats.

Lung volumes, diffusing capacity (DLCO), quasi-static pressure-volume curves (P-V), forced expiration (FE) and He-SF6 single-breath washout (SBW) were performed in Wistar rats with emphysema induced by different doses of pancreatic elastase in saline, instilled intratracheally 6 wk prior to the tests. Emphysema was quantitatively assessed by mean linear intercept (Lm) measurements on 5-microns lung sections. Lung volume, P-V curve, and FE dependence on Lm, as well as the nonsignificant dependence of DLCO on Lm, are generally similar to results reported by others. The most interesting observation concerns the SBW: N2 slopes of the alveolar plateau, compared for identical lung volumes, did not change with the degree of emphysema. By contrast, the He-SF6 slope difference did depend significantly on the degree of emphysema. Based on the diffusion front theory, the present work suggests that in rats with elastase-induced emphysema, the phase III slope modifications relate mainly to elastic and not to structural alterations.

Analysis of Variance↗
PubMed1995

New drug adoption models: a review and assessment of future needs.

New drug products today are the key to survival in the pharmaceutical industry. However, the new product development process in the pharmaceutical industry also happens to be one of the riskiest and most expensive undertakings because of the huge research and development costs involved. Consequently market forecasting of new pharmaceutical products takes on added importance if the formidable investments are to be recovered. New drug adoption models provide the marketer with a means to assess new product potential. Although several adoption models are available in the marketing literature for assessing potential of common consumer goods, the unique characteristics of the prescription drug market makes it necessary to examine the current state of pharmaceutical innovations. The purpose of this study, therefore, is to: (1) review new drug adoption models in the pharmaceutical literature, (2) evaluate the existing models of new drug adoption using the ten criteria for a good model as prescribed by Zaltman and Wallendorf (1983), and (3) provide an overall assessment and a ¿prescription¿ for better forecasting of new drug products.

Decision Theory↗
PubMed2000

Theory of a fixed scatterer embedded in a turbid medium: numerical results.

Based on a previous theory of diffuse photon density waves by Furutsu [J. Opt. Soc. Am. A 15, 1371 (1998)], several sets of figures are prepared to detect a fixed scatterer (object) embedded in a turbid layer, such as a tumor in tissue, with a source and a detector placed independently along the boundaries on different sides. The relative total intensity of the wave is introduced such that it is reduced to 1 in the case of no scatterer and usually less than that, owing to a shadowing by the scatterer. Sets of curves are presented to demonstrate shadow images of the scatterer observed along the layer boundaries depending on the scatterer's location.

Models, Theoretical↗
PubMed2004

Infant HIV infection: acceptability of preventive strategies in central Tanzania.

Safe, cost-effective interventions are being developed to reduce HIV transmission to children, suitable for lower income countries such as Tanzania. The interventions include Nevirapine treatment, replacement feeding, exclusive breast-feeding and heat-treating breast milk. This article reports on research to explore factors, which may influence the acceptability of these interventions. Data collection methods used were qualitative in-depth interviews with 12 health workers and focus group discussions with five community groups. Findings are presented with reference to the theory of diffusion of innovation, which seeks to explain how new ideas and products are disseminated through a community. Respondents describe the factors that may help and hinder this process. They propose ways to maximize this diffusion, such as integrating HIV and antenatal services, encouraging male participation, community-wide education, offering free HIV testing, and training health workers as change agents.

Adult↗
PubMed1981

Adoption of innovations from applied behavioral research: "Does anybody care?".

Applied behavioral researchers develop useful innovative technologies experimentally, and yet few of these technologies enjoy widespread adoption by our society. This paper analyzes several instances in which government agencies adopted behavioral technology, identifies 10 manipulable variables that could increase the rate of adoption of such technological innovations, and relates them to the field of knowledge diffusion. Unifying theory and experimental analysis are lacking in that field, yet an implicit technology may exist.

Journal Article↗
PubMed1996

Pain relief by various kinds of interference stimulation applied to the peripheral skin in humans: pain-related brain potentials following CO2 laser stimulation.

Pain perception is changed by various kinds of interference stimulation applied to the peripheral skin in humans. We investigated pain-related somatosensory evoked brain potentials (pain SEPs) following CO2 laser stimulation applied to the hand or foot in normal subjects, to elucidate the underlying mechanisms. A pain visual analogue scale (VAS) was also scored to determine the degree of subjective feeling of painful sensation. The following stimulations were applied as the interference: (1) vibration, (2) active and passive movements of the hand or foot, (3) noxious warming by hot water (46 degrees C) and (4) noxious cooling by ice water (0 degrees C). These interference stimulations were applied not only to the same hand or foot as the laser stimuli but also to the contralateral hand or foot. Significant changes in the amplitude of pain SEPs and VAS score were observed to some degree for each type of interference, and we concluded that gate control theory and diffuse noxious inhibitory control were the most appropriate hypotheses to account for this particular phenomenon of pain relief. Some movement-related cortical activities were also considered to be an important factor. These findings could not be accounted for by simple changes in the subjects' attention. Pain relief was more prominent at the second pain ascending through C fibers than that of the first pain ascending through Adelta fibers. The responsible sites for this phenomenon are considered to be the dorsal horn of the spinal cord, the brainstem and some parts of the brain such as the second sensory cortex and the cingulate cortex.

Brain↗
PubMed2001

[Bioethics and andrology].

In the present article the Author examines the relationship between Andrology and Bioethics. He takes into consideration the historical context in which the two new disciplines were born. They are practically coeval, being both come to the light about at the 60th years of XXth Century. He analyses the clinical problems of the sexuality and some diagnostic and therapeutic potentialities of the Andrology in connection with the implications of moral order. After synthetically outlining the most diffuse Bioethics' theories, and later outlining a scheme of methodological approach, he reaches the conclusions inclining for a personalist vision of the moral problems and he is wishing a theoretical and practical attitude by Andrology specialist doctor in conformity with virtues' ethics.

Andrology↗
PubMed2005

Using feedback to raise the quality of primary care computer data: a literature review.

BACKGROUND: Primary care is recognised as a medical specialty and its unique information needs justify the existence of its own health informatics sub-specialty: primary care informatics (PCI). A challenge for PCI is how to raise the standard of computerised medical records so that meaningful conclusions can be drawn from them. In the UK the Primary Care Data Quality (PCDQ) programme has eight years experience of using feedback in an educational context to improve data quality. OBJECTIVE: This literature review set out to define the characteristics of a feedback process most likely to achieve change; the principles of which could be applied to PCDQ or to other data quality initiatives. METHOD: A literature review of the major medical bibliographical databases, and the websites and working groups of the international medical informatics associations. RESULTS: There are generalisable lessons for primary care derived from the literature about implementing best evidence, feedback and the theory of diffusion of innovation. The principles identified are: (1) Engage and support local innovators - i.e. those most likely to adopt change, demonstrate the evidence-base for the intervention and the form of feedback most acceptable to them (2) Model the clinical context in which quality improvement is required; (3) Develop an understanding of the health system, its culture and management system; and, (4) Identify and address technical issues relating to computer use and coding. CONCLUSIONS: Feedback is most effective when: clinically relevant, educationally orientated, given by peers, and sensitive to the socio-technical context.

Feedback↗
PubMed2006

From the laboratory to the operatory.

The market for dental technology is expected to continue its growth, but to change in direction toward products based on biology. As the dental industry considers potential new technologies, it must consider the following components in the development process: patent protection of concepts, the clinical relevance of innovations, an overall business plan, the regulatory environment, manufacturing issues, testing required by the Food and Drug Administration, and marketing. The theory of diffusion of innovations proposed by Everett Rogers can be used to predict characteristics of technologies that will diffuse quickly and those users who will adopt innovations quickly or reluctantly.

Dental Instruments↗
PubMed1980

Diffusion control of the binding of carcinoembryonic antigen (CEA) with insoluble anti-CEA antibody.

Analysis of the kinetics of CEA binding to rabbit anti-CEA antibody insolubilized on filter paper discs provided six lines of evidence indicating diffusion control of this reaction: 1) The observed forward rate constant, k1obs, decreased when solvent viscosity was increased with sucrose or Ficoll. 2) k1obs per receptor site increased from 1.2 x 10(4) M-1 sec-1 to 2.6 x 10(4) M-1 sec-1 as receptor site density on immunosorbent discs decreased from 5.2 x 10(-13) to 2.1 x 10(-13) moles/disc. 3) Stirring the reacting mixture of CEA and insoluble anti-CEA increased k1obs from 1.2 x 10(4) M-1 sec-1 to 3.4 x 10(4) M-1 sec-1. 4) The activation energy for CEA-insoluble anti-CEA binding was indistinguishable (p greater than 0.1 by t-test) from 4.1 Kcal/mole expected for diffusion controlled reactions. 5) Bimolecular reaction theory predicted a diffusion limited forward rate constant, k1max, for CEA binding to insoluble anti-CEA, which was consistent with our observed k1 of 1.2 x 10(4) M-1 sec-1. 6) k1obs for CEA binding to soluble rabbit anti-CEA antibody was 6.4 x 10(4) M-1 sec-1, 5 times faster than the k1obs of the heterogeneous phase reaction for receptor site density of 5.2 x 10(-13) moles/disc. Diffusion control of ligand binding to insoluble receptors, as exemplified by the CEA-insoluble anti-CEA model system, may be a very general biologic phenomenon.

Animals↗