| 11. |
- Newman, J. D., et al.
(author)
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Biosensors for monitoring glucose
- 2004
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In: Sensors in medicine and health care. - : Wiley-VCH Verlagsgesellschaft. - 3527295569 - 9783527295562 ; , s. 45-78
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Book chapter (peer-reviewed)abstract
- Due to remarkable developments in the field of sensors along with miniaturization, sophisticated microsensors are part of many aspects of 21st century medicine and health care. Turning sensor inputs of all kinds into defined electrical signals that can be interpreted and acted upon by both stationary and portable medical equipment as well as implants, sensors find many applications monitoring blood pressure, heart rates, glucose levels and many other parameters by which human health can be evaluated. They also serve as key components in modern imaging equipment as well as operating equipment for minimally invasive surgery, catheters and other applications. Taken as a whole, Sensors Applications covers all major fields of application for commercial sensors, as well as their manufacturing techniques and major types. Strong emphasis is placed on microsensors, microsystems and integrated electronic sensor packages rather than bulk equipment. Each of the individual volumes is tailored to the needs and queries of readers from the relevan branches of industry and research.
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| 12. |
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| 13. |
- Pavlou, AK, et al.
(author)
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An intelligent rapid odour recognition model in discrimination of Helicobacter pylori and other gastroesophageal isolates in vitro
- 2000
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In: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 15:08-jul, s. 333-342
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Journal article (peer-reviewed)abstract
- Two series of experiments are reported which result in the discrimination between Helicobacter pylori and other bacterial gastroesophageal isolates using a newly developed odour generating system, an electronic nose and a hybrid intelligent odour recognition system. In the first series of experiments, after 5 h of growth (37 degreesC), 53 volatile sniffs were collected over the headspace of complex broth cultures of the following clinical isolates: Staphylococcus aureus, Klebsiella sp., H. pylori, Enterococcus faecalis (10(7) ml(-1)), Mixed infection (Proteus mirabilis, Escherichia coli, and E. faecalis 3 x 10(6) mi each) and sterile cultures. Fifty-six normalised variables were extracted from 14 conductive polymer sensor responses and analysed by a 3-layer back propagation neural network (NN). The NN prediction rate achieved was 98% and the test data (37.7% of all data) was recognised correctly. Successful clustering of bacterial classes was also achieved by discriminant analysis (DA) of a normalised subset of sensor data. Cross-validation identified correctly seven unknown samples. In the second series of experiments after 150 min of microaerobic growth at 37 degreesC, 24 volatile samples were collected over the headspace of H. pylori cultures in enriched (HPP) and normal (HP) media and 11 samples over sterile (N) cultures. Forty-eight sensor parameters were extracted from 12 sensor responses and analysed by a 3-layer NN previously optimised by a genetic algorithm (GA). GA-NN analysis achieved a 94% prediction rate or unknown data. Additionally the genetically selected 16 input neurones were used to perform DA-cross validation that showed a clear clustering of three groups and reclassified correctly nine sniffs. It is concluded that the most important factors that govern the performance of an intelligent bacterial odour detection system are: (a) an odour generation mechanism, (b) a rapid odour delivery system similar to the mammalian olfactory system, (c) a gas sensor array of high reproducibility and (d) a hybrid intelligent model (expert system) which will enable the parallel use of GA-NNs and multivariate techniques. (C) 1999 Elsevier Science S.A. All rights reserved.
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| 14. |
- Pavlou, AK, et al.
(author)
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Use of an electronic nose system for diagnoses of urinary tract infections
- 2002
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In: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 17:10, s. 893-899
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Journal article (peer-reviewed)abstract
- The use of volatile production patterns produced by bacterial contaminants in urine samples were examined using electronic nose technology. In two experiments 25 and 45 samples from patients were analysed for specific bacterial contaminants using agar culture techniques and the major UTI bacterial species identified. These samples were also analysed by incubation in a volatile generation test tube system for 4-5 h. The volatile production patterns were then analysed using an electronic nose system with 14 conducting polymer sensors. In the first experiment analysis of the data using a neural network (NN) enabled identification of all but one of the samples correctly when compared to the culture information. Four groups could be distinguished, i.e. normal urine, Escherichia coli infected, Proteus spp. and Staphylococcus spp. In the second experiment it was again possible to use NN systems to examine the volatile production patterns and identify 18 of 19 unknown UTI cases. Only one normal patient sample was mis-identified as an E coli infected sample. Discriminant function analysis also differentiated between normal urine samples, that infected with E coli and with Staphylococcus spp. This study has shown the potential for early detection of microbial contaminants in urine samples using electronic nose technology for the first time. These findings will have implications for the development of rapid systems for use in clinical practice. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 15. |
- Sandström, K. J. Mattias, et al.
(author)
-
A gas-phase biosensor for environmental monitoring of formic acid: laboratory and field validation
- 2003
-
In: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 5:3, s. 477-482
-
Journal article (peer-reviewed)abstract
- In order to encourage more exposure measurements to be performed, a formic acid gas-phase biosensor has been developed for this purpose. In the present paper, an enzyme based biosensor has been validated with respect to analyte selectivity and on-site use. To ensure that the sampler developed measures the compound of interest the biosensor was exposed to three near structural homologues to formic acid, i.e. acetic acid, methanol and formaldehyde. These vapours were generated with and without formic acid and the only compound that was found to have an effect on the performance of the biosensor, albeit a small one, was acetic acid. The field test was performed in a factory using formic acid-containing glue for glulam products. In parallel to the measurements with the biosensor a well defined reference method was used for sampling and analysing formic acid. It was found that the biosensor worked satisfactorily in this environment when used in a stationary position. It was also shown that the biosensor could determine formic acid vapour concentrations down to 0.03 mg m(-3).
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| 16. |
- Sandström, K. J. Mattias, et al.
(author)
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Amperometric biosensor for formic acid in air
- 2000
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In: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 70:1–3, s. 182-187
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Journal article (peer-reviewed)abstract
- The possibility of developing a simple, inexpensive and specific personal passive “real-time” air sampler incorporating a biosensor for formic acid was investigated. The sensor is based on the enzymatic reaction between formic acid and formate dehydrogenase (FDH) with nicotinamide adenine dinucleotide (NAD+) as a co-factor and Meldola's blue as mediator. An effective way to immobilise the enzyme, co-factor and Meldola's blue on screen-printed, disposable, electrodes was found to be in a mixture of glycerol and phosphate buffer covered with a gas-permeable membrane. Steady-state current was reached after 4–15 min and the limit of detection was calculated to be below 1 mg/m3. However, the response decreased by 50% after storage at −15°C for 1 day.
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| 17. |
- Sandström, K. J. Mattias, et al.
(author)
-
Multivariate evaluation of factors influencing the performance of a formic acid biosensor for use in air monitoring
- 2001
-
In: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 126:11, s. 2008-2014
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Journal article (peer-reviewed)abstract
- A formic acid biosensor for air monitoring has been evaluated using chemometric methods. Using experimental design eleven factors that could influence the performance of the biosensor were examined. The response matrices consisted of six parameters (steady state currents at three different formic acid concentrations and response rates during changes in formic acid concentrations) describing the performance of the biosensor. The data were evaluated using a combination of principal component analysis (PCA) and multiple linear regression (MLR). To confirm the conclusions from the PCA-MLR partial least squares (PLS) was also used. The most important factor for the biosensor performance was found to be the enzyme concentration. Using the information from the chemometric analyses the optimum operation conditions for the biosensor were determined. The steady state currents were increased by 18-30% and the initial two response rates increased by 47-89% compared with a biosensor that had not been optimised.
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| 18. |
- Turner, C, et al.
(author)
-
Supercritical fluid extraction and chromatography for fat-soluble vitamin analysis.
- 2001
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In: Journal of Chromatography A. - 0021-9673. ; 936:1, s. 37-215
-
Journal article (peer-reviewed)abstract
- Extraction and chromatographic separation of fat-soluble vitamins is a challenging task, due to the sensitivity of these compounds towards light, oxygen, heat and pH. In light of this, supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) are attractive techniques as they function at considerably milder conditions than conventional solvent-based analytical techniques. Moreover, supercritical techniques consume much less amounts of organic solvents than conventional ones. This review gives a brief description of suitable supercritical media as well as basic theory on SFE and SFC processes. Furthermore, guidelines are provided for optimizing the important extraction and separation parameters to facilitate a successful method development. Finally, applications employing SFE and/or SFC for fat-soluble vitamin enrichment and final determination are reviewed.
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| 19. |
- Turner, J. Rodney, et al.
(author)
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communication and co-operation on projects between the project owner as principal and the project manager as agent
- 2004
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In: European Management Journal. - : Elsevier BV. - 0263-2373. ; 22:3, s. 327-336
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Journal article (peer-reviewed)abstract
- Research shows the best project performance is obtained when there is high collaboration between client and project manager, and medium levels of structure, when the project manager and project owner work together in partnership, and the manager is empowered. Unfortunately, this is not how it happens on many projects. There is mistrust, even conflict, between owner and manager, and the owner sets tight constraints within which the manager must work. Project owners mouth partnership and empowerment, but implement conflict and tight control. In this paper, we offer the principal-agency relationship between client and project manager as one reason for this. However, we offer communication between the client and project manager as a way of reducing this problem. We suggest what communication the client needs from the project manager, and what communication the project manager needs from the client to minimize the impact of the principal-agency relationship. We report the results of an international study into communication needs on projects. We establish that the communication needs of project participants are best served by a mixture of formal and informal communication, and of written and verbal communication. We also establish that communication and emotion are closely linked on projects.
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| 20. |
- Turner, J. Rodney, et al.
(author)
-
On the nature of the project as a remporary organization
- 2003
-
In: International Journal of Project Management. - 0263-7863. ; 21:1, s. 1-8
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Journal article (peer-reviewed)abstract
- The nature of the project as a temporary organization is analysed from the perspective of organizational theory. This leads to a reassessment of the definition of a project. It is suggested that classical definitions of projects are not wrong, just incomplete. The project as a temporary organization is viewed here as a production function, as an agency for assigning resources to the management of change within the functional organization, and as an agency for managing uncertainty. The role of the project manager is also considered. The project manager is chief executive of the temporary organization, and thus their roles in objective setting and motivating team members are emphasized over their role in planning and executing work. Second, as manager of the agency, they are the agent of the owner (principal) and so a second hierarchy of management and control must be put in place to monitor their performance. These agency costs add to the cost of the project, but may also explain why professional recognition is so important to project managers.
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