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Biomedical subjects

M L Johns

Publications and source records attributed to M L Johns.

27 records · Page 2Linked to original sources
PubMed1990

The CIO and IRM (information resources management) alliance: maneuvering for the competitive edge in hospital information management.

In 1986, Johns noted that "The hospital industry was caught unprepared for the external demands and information needs required in a case-mix reimbursement environment." Lack of a data-processing philosophy and inattention to external forces were cited as having hampered technology upgrade and integration of financial and clinical databases. The intervening years have witnessed a growth of information dissemination in the health care industry concerning information value and resource management. The frequency of appearance of articles on information management in the professional literature and the number of workshops and professional meetings addressing the topic attest to the current visibility of the information resource. Despite this flurry of interest, the industry has not developed its own models of information resources management nor validated its information evolution with accepted management information systems models. While interest in health care information resource management exists, understanding of the complex issues in this area has not developed as one would expect. While there are a myriad of reasons for this, a contributing factor is the lack of a research foundation for development and application of theory and models. Even though various graduate programs exist in medical informatics and biomedical computing, few concentrate on the study of health information resource management from an organizational perspective. Because of this, academic research in the area has been minimal. The scarcity of graduate-level programs has also meant that few individuals have been educated to deal with the challenges of managing the many disparate functional activities associated with health care information resource management. Due to a variety of internal and external forces, extreme demands were placed on the hospital information resource during the past decade.(ABSTRACT TRUNCATED AT 250 WORDS)

Hospital Administrators↗
PubMed1980

Evaluation of malonyl-CoA in the regulation of long-chain fatty acid oxidation in the liver. Evidence for an unidentified regulatory component of the system.

Palmitate oxidation by liver mitochondria from fed and starved rats exhibited markedly different sensitivities to inhibition by malonyl-CoA. In the mitochondrial system from fed rats, 50% inhibition required 19 muM-malonyl-CoA, whereas the mitochondria from starved rats were by comparison refractory to malonyl-CoA. Inhibition by malonyl-CoA was completely reversed by increasing the molar ratio of fatty acid to albumin. Results indicate that the potential effectiveness of malonyl-CoA as an inhibitor of fatty acid oxidation in the liver is dependent on an unidentified regulatory component of the system. The functional activity of this component is modified by the nutritional state, and its site of action is at the mitochondrial level.

Acyl Coenzyme A↗
PubMedDate not supplied

Magnetic resonance imaging study of complex fluid flow in porous media: flow patterns and quantitative saturation profiling of amphiphilic fracturing fluid displacement in sandstone cores.

Magnetic resonance imaging is used to follow the removal process of a visco-elastic surfactant (VES) fracturing fluid in Bentheimer sandstone cores at typical reservoir temperatures (T=333 K). Two displacing fluids were investigated, a Gadolinium doped water phase (1M NaCl solution), and a Gadolinium doped hydrocarbon phase (Mineral Spirits). In addition to flow characteristics obtained by conventional core-flooding, i.e., the macroscopically averaged volumetric flow rates and differential pressures, we have also measured the saturation profiles and characteristic displacement patterns during all stages of the removal process. To acquire these data we have used quantitative one-dimensional chemically specific profiling along with fast two-dimensional imaging experiments while flooding Bentheimer sandstone cores in situ in the spectrometer. Our results show that both displacement processes (complex fluid displaced by water or hydrocarbon phase) are dominated by the large viscosity contrasts present. However, distinct differences were found between the displacement characteristics of water and hydrocarbon, which confirmed the sensitivity of the complex fracturing fluid to the displacing fluid.

Gadolinium↗
PubMedDate not supplied

Magnetic resonance studies of dissolving particulate solids.

Magnetic resonance methods have been used to elucidate the internal pore structure of particulate solids, in particular detergent tablets. Such information is essential to a comprehensive understanding of the dissolution characteristics of these materials and how this property is related to processing conditions during tablet formation. In particular 3-D images of porosity are produced and 2-D self-diffusion maps are acquired as a function of observation time, which enables pore size to be quantified as a function of position via the extracted surface-to-volume ratio of the pore space. These properties are determined as a function of processing parameters, in particular the compression force used in tablet formation.

Detergents↗
PubMedDate not supplied

MRI study of non-aqueous phase liquid extraction from porous media.

Magnetic resonance imaging is used to investigate, at the pore scale, the dissolution and mobilisation of discrete non-aqueous phase liquid (octanol) ganglia trapped within porous media by capillary forces, by a mobile aqueous phase. Dissolution is observed to be described by a mass-transfer limited model. Mobilisation of entrapped ganglia commences at lower flowrates when a surfactant is introduced into the mobile aqueous phase.

1-Octanol↗
PubMedDate not supplied

Visualisation of structure and flow in packed beds.

Magnetic resonance imaging (MRI) volume- and velocity-measurement techniques are used to probe structure-flow correlations within the interparticle space of a packed bed of ballotini. Images of the three mutually orthogonal components of the velocity field are obtained in axial and radial image slices within a bed of 5-mm-diameter ballotini, packed within a glass column of internal diameter 4.6 cm. A three-dimensional volume image of the bed is also obtained and analysed to partition the interparticle space into individual pores and determine the location of pore necks. Significant heterogeneity in the flow is observed; in one slice approximately 8% of the pores carry 40% of the volume flow. The characteristics of pores carrying anomalously high values of fluid flow rate and velocity are investigated.

Humans↗
PubMedDate not supplied

Magnetic resonance imaging studies of diffusion in polymers.

For a number of polymer/penetrant systems, for example fatty foods in direct contact with plastic wrapping, the migration of substances from the polymer is governed by the amount of penetrant entering the polymer. For food packaging this means that the rate of migration of substances into the food can be governed by the uptake of food into the packaging itself. To develop predictive models of migration under various conditions there is therefore a need to understand the mechanism of the penetration of the food into the packaging. In this paper a summary of recent Magnetic Resonance Imaging (MRI) studies is reported. Uptake of simulant, as measured by MRI, is quantitative and agrees well with gravimetric uptake data. Data are shown for a comparison of olive oil and isooctane penetration into low density polyethylene at various temperatures. Further, the rate of ingress of isooctane into a variety of commercial polyethylene plaques has been shown to differ widely. These data also allow us to probe the molecular interactions between polymer and penetrant. Finally MRI is combined with a Pulsed Gradient Spin Echo (PGSE) technique to provide spatially resolved measurements of penetrant diffusivity within a polymer. Diffusivity as a function of volume fraction of penetrant can also be measured. These data provide invaluable insights into diffusion in polymers which will aid development of more accurate models of polymer/penetrant interactions and small molecule mobility.

Diffusion↗