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Microbial growth in a mixture of hyperbaric bupivacaine and fentanyl prepared in a multi-dose syringe in the operating theatre environmentMorgan, Gwen 24 January 2013 (has links)
Introduction
A protocol has been devised in which a 20ml mixture of hyperbaric bupivacaine and fentanyl is prepared in a multi-dose syringe, from which aliquots are withdrawn into individual sterile syringes for use in spinal anaesthesia. The risk of microbial contamination of these multi-dose syringes is unknown and this study was designed to assess such risk.
Methodology
In this pilot study, each syringe was prepared using non-aseptic technique to contain a mixture comprising Fentanyl 10 μg.ml-1, Bupivacaine 4mg.ml-1and Dextrose 64mg.ml-1, with a total volume of 20ml. Syringes were then allocated to pairs. Aliquots were withdrawn hourly from one syringe of each pair for a twelve-hour study period, whilst the other syringe was sampled only at the beginning and end of the same period. All aliquots were withdrawn using standard aseptic technique in an operating theatre environment. For each syringe pair, both samples from the control syringe and four of the samples from the multi-dose syringe were submitted for microbiological culture.
Results
Of the 120 samples taken, one sample was excluded. Of the remaining 119 samples submitted for microbiological investigation, only one yielded growth. This sample had been taken from a multi-dose syringe at the beginning of the study period. Subsequent samples withdrawn from the same syringe were found to be sterile. The organism which had been cultured from this sample was Staphylococcus aureus (S. aureus).
Conclusion
It is possible that the culture medium which yielded the microbial growth was contaminated, which would explain why subsequent samples from the same syringe were sterile. Alternatively, bupivacaine is known to be strongly antimicrobial against some pathogens and it is conceivable that there may have been initial contamination of the syringe by S. aureus, which was inhibited by the bupivacaine to produce subsequent sterile samples. Whilst this may suggest that the use of multi-dose syringes for spinal anaesthesia could be safe, in light of the inconclusive result, further investigation is warranted.
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Analytical and numerical continuation methods for conductive temperature fieldsEggers, Dwight Edward 17 July 1975 (has links)
The continuation of conductive temperature fields is being
considered. The continuation of a field involves the extrapolation of a
field known over a limited domain to an adjacent domain in such a way
that it satisfies the heat conduction differential equation and other
imposed constraints. Continuations forward in time and toward the
interior of the space from the constraining initial and boundary conditions
are expressed analytically as convolution integrals. Solutions
are approximated using linear filter methods in real and transform
spaces. The inverse problems of continuation toward the constraining
conditions are expressed in real space as power series of derivatives.
Solutions are approximated as convolution filtering operations.
Variational methods are also used to solve problems which do not
yield to convolution filtering operations. The suitability of these
approximation methods is shown in two ways: (1) the frequency
response of the derived convolution coefficients are compared with the
analytic transfer functions; and (2) the methods are applied to artificial
test cases.
These field continuation methods provide a tool for the
interpretation of observational temperature data. Several examples
of field data are treated using these techniques; (1) A case of the
temperature inversion observed in a geothermal borehole is explained
by a transient flow of thermal water along a narrow horizontal fracture;
(2) Soil temperature data are treated to determine the in situ
thermal diffusivity and show that departures from conductive conditions
are accounted for by evaporative effects; (3) Shallow borehole
temperature data which exhibit the nonstationary effects of the annual
cycle are shown to be influenced by convective effects in the soil. / Graduation date: 1976
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Etude ab initio de la résistivité de l'aluminium, le sodium, le plomb et le manganèse en phase liquideKnider, Fatima Hugel, Joseph. January 2007 (has links) (PDF)
Thèse de doctorat : Physique : Metz : 2007. / Thèse soutenue sur ensemble de travaux. Bibliogr. f. 123-124. Acronymes f. 5.
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Flow through thin triangular sectionsMarburger, Ivan Lloyd, 1931- January 1960 (has links)
No description available.
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Transient heat conduction in infinite plates situated in a fourth-power radiative environmentCrawford, Martin 12 1900 (has links)
No description available.
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The measurement of thermal conductivity at high temperaturesBowen, Mack Donald 05 1900 (has links)
No description available.
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The prediction of heat transfer in rough pipesMcAndrew, Murray Alexander January 1962 (has links)
An evaluation of methods for predicting turbulent heat transfer in rough pipes has been made with the intention of obtaining a better understanding
of the transfer processes involved and of providing a general design equation, valid for all types of roughness shapes and distributions. The equations of Martinelli, Nunner, and Mattioli, along with an empirical method suggested by Epstein, have been tested using the available experimental data. In addition, particular attention has been given to a proposed method which makes use of the velocity profile equations of Rouse and von Karman in Lyon's fundamental equation for the Nusselt number.
The results indicate that the proposed method is not successful, largely because of ignorance of velocity conditions near the walls of rough pipes. Mattioli's equation also does not give a satisfactory correlation of experimental results. Epstein's empirical method, which, in the pertinent dimensionless groups, uses friction velocity and equivalent sand-roughness height of the roughness elements in place of the average fluid velocity and the pipe diameter, respectively, shows promise but requires further investigation. Nunner's equation and Martinelli's (simplified) equation give good prediction of the experimental results and are recommended for use at present, providing 0.5 < Pr < 1.0. The success of these latter equations gives support to the hypothesis that the fluid adjacent to a rough wall is probably in laminar motion.
Using Nunner's model of the flow conditions in rough pipes, equations have been derived for predicting temperature profiles from velocity profile data. Generally, the absolute agreement between predicted profiles and Nunner’s experimental profiles is good, but the influences of Re and especially f are not too well accounted for. Nunner's conclusion that temperature and velocity profiles in rough pipes are not similar is substantiated by the results. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate
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Certain steady state and transient time phenomena in heat conductionHadley, Charles Wendell. January 1940 (has links)
LD2668 .T4 1940 H34 / Master of Science
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Heat conduction in polycrystalline metal films鍾業華, Chung, Yip-wah. January 1973 (has links)
published_or_final_version / Physics / Master / Master of Philosophy
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Metal-insulator-metal electron emitters and their applications in surface chemistrySharpe, Robert George January 1994 (has links)
No description available.
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