| 1. |
- Ridefelt, Peter, et al.
(författare)
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Diurnal variability of total calcium during normal sleep and after an acute shift of sleep
- 2012
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 50:1, s. 147-151
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Tidskriftsartikel (refereegranskat)abstract
- Background: Serum total calcium is becoming a widely used test when screening for hyperparathyroidism (HPT) and other causes of hypercalcemia, even if serum calcium is tightly regulated in the body it is unclear whether the reference values are correct for tests taken at different times of the day or for individuals with altered sleep patterns. Thus, the aim was to investigate how timing of testing and sleep affects serum calcium. Methods: The diurnal variation of total calcium in serum during night-time and day-time conditions was studied in seven healthy volunteers. Serum samples for calcium measurements were collected every hour (48 samples per individual) to evaluate the effect of sampling times, sleep and food intake on the test results. Results: The median intra-individual coefficients of variations for calcium were 3.3% during night-time sleep and 2.8% during day-time sleep conditions. There was a clear diurnal variation in serum calcium, with a trough at 08.00 h in the morning after night-time sleep and a difference of approximately 0.07 mmol/L between trough and peak. Calcium was lower around the end of the sleep periods, for both night-time and day-time sleep. Food intake did not affect calcium concentrations. Conclusions: Evaluation of serum calcium results should take diurnal variation into account and allow slightly higher calcium values in the afternoon in comparison with samples collected in the morning.
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| 2. |
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| 3. |
- Holmer, Mattias, et al.
(författare)
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Heart Rate Estimation from Dual Pressure Sensors of a Dialysis Machine
- 2015
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Ingår i: 2015 Computing in Cardiology Conference (CinC). - 2325-8861. ; 42, s. 29-32
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Konferensbidrag (refereegranskat)abstract
- Dialysis patients often suffer from cardiovascular dis- eases, motivating the use of continuous monitoring of car- diac activity in clinical routine. Cardiac pressure pulses propagate through the vascular system and enter the ex- tracorporeal blood circuit of a dialysis machine, where the pulses are captured by pressure sensors. The cardiac pulses are obscured by the much stronger pressure pulses originating from the peristaltic blood pump. We have pre- viously shown that a cardiac signal can be extracted from the venous pressure signal. However, that method has been found to perform less well at very low cardiac pressure pulse amplitudes. In the present study, we propose a novel method which addresses this issue by using the signals from both the arterial and the venous pressure sensors. The method is compared to the previous method on clini- cal data using a photoplethysmogram as reference. The re- sults suggests that heart rate can be estimated more accu- rately from pressure signals with lower cardiac signal am- plitude when both arterial and venous pressure are used, compared to when only the venous signal is used.
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| 4. |
- Suntornwipat, Nattakarn, et al.
(författare)
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Magnetotransport study of valley-polarized electrons in synthetic diamond
- 2016
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Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 94:3
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that the highly stable valley-polarized electron states in ultrapure single-crystalline diamond allow for investigation of charge transport, magnetoresistivity, and determination of the dominant scattering mechanism. The Hall effect gives rise to nonisotropic contributions in the mobility tensor that were measured at a temperature of 70 K in a time-of-flight setup with an added magnetic field. The observations of the magnetotransport of valley-polarized electrons in diamond are compared with both Monte Carlo simulations and an analytical model based on the Boltzmann transport equation. We establish that acoustic phonon scattering is the dominant electron scattering mechanism at 70 K for each of the valley polarizations in the investigated samples.
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| 5. |
- Schmallegger, Doris, et al.
(författare)
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Tourist populations and local capital
- 2011
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Ingår i: Demography at the edge. - Farnham : Ashgate. - 9780754679622 - 9780754699156 ; , s. 271-288
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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