| 1. |
- Alfredson, Håkan, et al.
(författare)
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In vivo investigation of ECRB tendons with microdialysis technique--no signs of inflammation but high amounts of glutamate in tennis elbow.
- 2000
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Ingår i: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 71:5, s. 475-479
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Tidskriftsartikel (refereegranskat)abstract
- We used the microdialysis technique to study concentrations of substances in the extensor carpi radialis brevis (ECRB) tendon in patients with tennis elbow. In 4 patients (mean age 41 years, 3 men) with a long duration of localized pain at the ECRB muscle origin, and in 4 controls (mean age 36 years, 2 men) with no history of elbow pain, a standard microdialysis catheter was inserted into the ECRB tendon under local anesthesia. The local concentrations of the neurotransmitter glutamate and prostaglandin E2 (PGE2) were recorded under resting conditions. Samplings were done every 15 minutes during a 2-hour period. We found higher mean concentrations of glutamate in ECRB tendons from patients with tennis elbow than in tendons from controls (215 vs. 69 micromoL/L, p < 0.001). There were no significant differences in the mean concentrations of PGE2 (74 vs. 86 pg/mL). In conclusion, in situ microdialysis can be used to study certain metabolic events in the ECRB tendon of the elbow. Our findings indicate involvement of the excitatory neurotransmitter glutamate, but no biochemical signs of inflammation (normal PGE2 levels) in ECRB tendons from patients with tennis elbow.
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| 2. |
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| 3. |
- Persson, Magnus, et al.
(författare)
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Predicting the dielectric constant-water content relationship using artificial neural networks
- 2002
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Ingår i: Soil Science Society of America Journal. - : Wiley. - 0361-5995. ; 66:5, s. 1424-1429
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Tidskriftsartikel (refereegranskat)abstract
- Accurate measurements of soil water content (theta) are important in various applications in hydrology and soil science. The time domain reflectometry (TDR) technique has been widely used for theta measurements during the last two decades. The TDR utilizes the apparent dielectric constant (K-s) for estimations of theta. The K-a-theta relationship has been described using both empirical and physical models. Universal calibration equations that fit a wide range of different soil types have been developed. However, to achieve high accuracy, a soil-specific calibration needs to be conducted. In the present study, we use an artificial neural network(ANN) to predict the K-a-theta relationship using soil physical parameters for ten different soil types. The parameters that give the most significant reduction in the root mean square error (RMSE) are bulk density, clay content, and organic matter content. The K-a-theta relationship for each soil type is predicted using the other nine for calibration. It is shown that ANN predictions are as good as a soil specific calibration with comparable coefficient of determination and RMSE. Thus, by using ANN, highly accurate data can be obtained without need for elaborate soil specific calibration experiments.
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| 4. |
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| 5. |
- Sivakumar, B, et al.
(författare)
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Is correlation dimension a reliable indicator of low-dimensional chaos in short hydrological time series?
- 2002
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Ingår i: Water Resources Research. - 0043-1397. ; 38:2
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Tidskriftsartikel (refereegranskat)abstract
- The reliability of the correlation dimension estimation in short hydrological time series is investigated using an inverse approach. According to this approach, first predictions are made using the phase-space reconstruction technique and the artificial neural networks. The correlation dimension is estimated next independently and is compared with the prediction results. A short hydrological series, monthly runoff series of 48 years (with a total of only 576 values) observed at the Coaracy Nunes/Araguari River watershed in northern Brazil, is studied. The correlation dimension results are in reasonably good agreement with the optimal embedding dimension obtained from the phase-space method and the optimal number of inputs from the neural networks. No underestimation of the correlation dimension is observed due to the small data size, rather there seems to be a slight overestimation due to the presence of noise in the data. The results indicate that the accuracy of the correlation dimension may not be judged on the basis of the length of the time series but on whether the time series is long enough to reasonably represent the dynamical changes in the system. Such an observation suggests that the correlation dimension could indeed be a reliable indicator of low-dimensional chaos even in short hydrological time series, which is certainly encouraging news for hydrologists who often have to deal with short time series.
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| 6. |
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| 7. |
- Sivakumar, B., et al.
(författare)
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Preuve de l’0existence de chaos dans le processus pluie-débit
- 2001
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 46:1, s. 131-145
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Tidskriftsartikel (refereegranskat)abstract
- The transformation of rainfall into runoff is one of the most important processes in hydrology. In the past few decades, a wide variety of automated or computer-based approaches have been applied to model this process. However, many such approaches have an important limitation in that they treat the rainfall-runoff process as a realization of only a few parameters of linear relationships rather than the process as a whole. What is required, therefore, is an approach that can capture not only the overall appearance but also the intricate details of the nonlinear behaviour of the process. The purpose of this study is to investigate the possibility of understanding the dynamics of the rainfall-runoff process from a new perspective, as a chaotic process. The possible existence of chaotic behaviour in the rainfall-runoff process is studied by investigating the rainfall and runoff time series: (a) separately; and (b) jointly (using the runoff coefficient). Monthly rainfall and runoff observed over a period of 131 years (January 1807-December 1937) at the Göta River basin in the south of Sweden are analysed. The correlation dimension method is employed to identify the presence of chaos. The correlation dimensions obtained for the rainfall and runoff time series are 6.4 and 5.5, respectively. The finite dimensions obtained for the rainfall and runoff time series indicate the possible existence of chaos in these processes, implying that the joint rainfall-runoff process might also exhibit chaotic behaviour. The correlation dimension of about 7.8 obtained for the runoff coefficient also indicates the possible presence of chaos and supports the above results.
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| 8. |
- Svedhem, V, et al.
(författare)
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Disseminated infection with Encephalitozoon intestinalis in AIDS patients: Report of 2 cases
- 2002
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 34:9, s. 703-705
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Tidskriftsartikel (refereegranskat)abstract
- Microsporidiosis must be regarded as a late opportunistic infection when HIV is advanced. In this article we describe 2 cases of disseminated infection with Encephalitozoon intestinalis. The first case had a local intestinal infection for > 1 y before it disseminated and microsporidia were found intracellularly in sputum. In the second case, spores were initially found in conjunctival cells, sinus lavage, sputum and urine. This patient had clinical symptoms and radiological findings from the central nervous system. Signs of cerebral lymphoma developed after treatment of the opportunistic microsporidial infection.
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