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- Christiansson, Lennart, et al.
(författare)
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A new method of intrathecal PO2, PCO2, and pH measurements for continuous monitoring of spinal cord ischemia during thoracic aortic clamping in pigs
- 2000
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Ingår i: Surgery. - : Elsevier BV. - 0039-6060 .- 1532-7361. ; 127:5, s. 571-576
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Impaired spinal cord circulation during thoracic aortic clamping may result in paraplegia. Reliable and fast responding methods for intraoperative monitoring are needed to facilitate the evaluation of protective measures and efficiency of revascularization.METHODS: In 11 pigs, a multiparameter PO2, PCO2, and pH sensor (Paratrend 7, Biomedical Sensors Ltd, United Kingdom) was introduced into the intrathecal space for continuous monitoring of cerebrospinal fluid (CSF) oxygenation during thoracic aortic cross-clamping (AXC) distal to the left subclavian artery. A laser-Doppler probe was inserted into the epidural space for simultaneous measurements of spinal cord flux. Registrations were made before and 30 minutes after clamping and 30 and 60 minutes after declamping. The same measuring points were used for systemic hemodynamic and metabolic data acquisition.RESULTS: The mean CSF PO2 readings of 41 mm Hg (5.5 kPa) at baseline decreased within 3 minutes to 5 mm Hg (0.7 kPa) during AXC (P < .01). Spinal cord flux measurement responded immediately in the same way to AXC. Both methods indicated normalization of circulation during declamping. Significant (P < .01) changes were also observed in the CSF metabolic parameters PCO2 and pH.CONCLUSIONS: In this experimental model of spinal ischemia by AXC, online monitoring of intrathecal PO2, PCO2, and pH showed significant changes and correlated well with epidural laser-Doppler flowmetry (P < .01).
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| 4. |
- Grip, Helena, et al.
(författare)
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Classification of Neck Movement Patterns Related to Whiplash-Associated Disorders Using Neural Networks
- 2003
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Ingår i: IEEE transactions on information technology in biomedicine. - : IEEE. - 1089-7771 .- 1558-0032. ; 7:4, s. 412-418
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a new method for classification of neck movement patterns related to Whiplash-associated disorders (WAD) using a resilient backpropagation neural network (BPNN). WAD are a common diagnosis after neck trauma, typically caused by rear-end car accidents. Since physical injuries seldom are found with present imaging techniques, the diagnosis can be difficult to make. The active range of the neck is often visually inspected in patients with neck pain, but this is a subjective measure, and a more objective decision support system, that gives a reliable and more detailed analysis of neck movement pattern, is needed. The objective of this study was to evaluate the predictive ability of a BPNN, using neck movement variables as input. Three-dimensional (3-D) neck movement data from 59 subjects with WAD and 56 control subjects were collected with a ProReflex system. Rotation angle and angle velocity were calculated using the instantaneous helical axis method and motion variables were extracted. A principal component analysis was performed in order to reduce data and improve the BPNN performance. BPNNs with six hidden nodes had a predictivity of 0.89, a sensitivity of 0.90 and a specificity of 0.88, which are very promising results. This shows that neck movement analysis combined with a neural network could build the basis of a decision support system for classifying suspected WAD, even though further evaluation of the method is needed.
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| 5. |
- Ihs, Anita, et al.
(författare)
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Vägytans inverkan på körkomforten : bilisters monetära värdering av komfort
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The decision support system for the maintenance of paved roads, PMS, of theSwedish National Road Administration comprises a number of models forestimating the costs of road management authorities, road users and societyat large. In 1998 VTI was commissioned by the Road Administration to carryout a comprehensive project with the objective of revising and augmentingthese traffic effect models. The project is entitled "Traffic effects of theroad surface" and has comprised a number of subprojects. The primary aim ofthis study has been to investigate, in a field study, the relationshipbetween the roughness of the road surface (expressed in terms of theInternational Roughness Index IRI, with the units mm/m) and the perceiveddriving comfort of motorists, as well as their willingness to pay forimproved driving comfort. 50 test subjects were asked to drive a car overnine 500 m long sections with different surface standards. The mean of themeasured IRI on these road sections varies from 0.8 mm/m on the smoothestsection to 10.5 mm/m on the roughest. In conjunction with the investigation,the test subjects were interviewed by a test leader. During the interview,they were asked which factors are significant for driving comfort and howthey perceived driving comfort on the different sections. The state/conditionof the asphalt surfacing was considered to have the greatest significance,followed by the car and the behaviour of other road users. Density of trafficwas considered to have the least significance. The test subjects were alsoasked to say what significance different defects in the surfacing had ondriving comfort. What is most important for a comfortable car journey is thatthere are no holes/depressions in the surfacing. This is followed by ruts,roughness that causes vibrations, and bumps and subsidence. The test subjectswere asked to make a general assessment of driving comfort on a five-degreescale during their drive over the nine sections. A clear relationship wasfound between the assessment that the test subjects made and the measuredIRI, i.e. the higher the IRI, the worse driving comfort was judged to be.The physical impact caused by the different surface standards of the testsections was also investigated by placing a dummy equipped with triaxialaccelerometers in the passenger seat of the car that drove over the testsections. The willingness of the test subjects to pay for improved comfortassociated with the condition of the road surface was also investigated bythree methods: Stated Preference (Choice) and Contingent Valuation Method(driving comfort versus petrol price and trip time). A relatively highwillingness to pay was obtained, but the methods gave very different results.It has therefore been impossible to posit a comfort cost model on the basisof these. This requires further studies and development of the methods.
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| 7. |
- Sanchez-Agudo, M, et al.
(författare)
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3p -> 3d resonant photoemission spectroscopy of a TiO2 sub-monolayer grown on Al2O3
- 2004
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Ingår i: Proceedings of the 22nd European Conference on Surface Science (Surface Science). - : Elsevier BV. - 0039-6028. ; 566-68:Part 1, s. 515-519
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Konferensbidrag (refereegranskat)abstract
- The valence band resonant photoemission spectra of a TiO2 sub-monolayer grown on an Al2O3 substrate have been measured throughout the Ti 3p absorption edge, i.e. at photon energies between 40 and 60 eV. The resonance process has been analysed in terms of constant initial state (CIS) curves, showing a peak at 49.5 eV photon energy, corresponding to a Fano-like resonant process. The Ti 3d contribution to the valence band shows a significant energy shift with respect to bulk TiO2. These results are compared to cluster model calculations for a TiO6 cluster. (C) 2004 Elsevier B.V. All rights reserved.
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| 8. |
- Wiklund, Stefan, et al.
(författare)
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Vibrational analysis of the C 1s photoemission spectra from pure ethylidyne and ethylidyne coadsorbed with carbon monoxide on Rh (111)
- 2000
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Ingår i: Surface Science. - 0039-6028. ; 461:1-3, s. 107-117
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution core-level photoemission with a resolution better than the intrinsic width of the C 1s level has been used to study pure and coadsorbed ethylidyne overlayers on Rh(111). Components due to excitation of the C-H stretch vibration are clearly resolved in the C 1s spectra. In addition, a component due to the C-C vibration of the ethylidyne molecules is identified. The asymmetry parameter is found to be similar for the two carbon atoms of the C2H3 molecule, indicating similar densities of states at the Fermi level for the two atoms. Coadsorption of ethylidyne with CO is found to induce a large C 1s binding-energy shift of the outer carbon atom of the ethylidyne. The remaining lineshape parameters, including the energy splits and intensity ratios of the C-H vibrational progressions, are similar for the pure and coadsorbed ethylidyne.
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| 9. |
- Wågberg, Lars-Göran, et al.
(författare)
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Litteraturstudie av däckdubbars effekt på vägslitage, väglag, trafiksäkerhet och miljö
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Detta notat är en sammanställning av en litteraturstudie av effekter av dubbdäcksanvändning. Studerade effekter omfattar slitage friktion, väglag, säkerhet och miljö. Studien har genomförts under kort tid, ungefär en månad, vilket innebär att den inte kunnat bli fullständig och heltäckande. Värdering av effekter har inte ingått i studien. Studien har alltså haft begränsad omfattning och värdering av effekter har inte kartlagts. Det medför att det inom ramen för denna studie inte finns utrymme för att genomföra en analys av olika åtgärder för att minska dubbdäcksanvändningen.
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| 10. |
- Öhberg, Fredrik, et al.
(författare)
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Chronic Whiplash Associated Disorders and Neck Movement Measurements : An Instantaneous Helical Axis Approach
- 2003
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Ingår i: IEEE transactions on information technology in biomedicine. - : IEEE. - 1089-7771 .- 1558-0032. ; 7:4, s. 274-282
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an assessment tool for objective neck movement analysis of subjects suffering from chronic whiplash-associated disorders (WAD). Three-dimensional (3-D) motion data is collected by a commercially available motion analysis system. Head rotation, defined in this paper as the rotation angle around the instantaneous helical axis (IHA), is used for extracting a number of variables (e.g., angular velocity and range, symmetry of motion). Statistically significant differences were found between controls and subjects with chronic WAD in a number of variables.
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