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- Hedner, Jan A, 1953, et al.
(author)
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A novel adaptive wrist actigraphy algorithm for sleep-wake assessment in sleep apnea patients
- 2004
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In: Sleep. ; 27:8
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Journal article (peer-reviewed)abstract
- STUDY OBJECTIVES: Current actigraphic algorithms are relatively less accurate in detecting sleep and wake in sleep apnea patients than in people without sleep apnea. In the current study, we attempted to validate a novel automatic algorithm, which was developed for actigraphic studies in normal subjects and patients with obstructive sleep apnea by comparing it on an epoch-by-epoch basis to standard polysomnography. DESIGN: Prospective cohort study. SETTING: Multicenter, university hospital, sleep laboratories. PARTICIPANTS: A total of 228 subjects from 3 different sleep centers (Skara, Boston, Haifa) participated. INTERVENTION AND MEASUREMENTS: Simultaneous recording of polysomnography and Watch_PAT100, an ambulatory device that contains a built-in actigraph. The automatic sleep/wake algorithm is based on both the quantification of motion (magnitude and duration) and the various periodic movement patterns, such as those occurring in patients with moderate to severe obstructive sleep apnea. RESULTS: The overall sensitivity and specificity to identify sleep was 89% and 69%, respectively. The agreement ranged from 86% in the normal subjects to 86%, 84%, and 80% in the patients with mild, moderate, and severe obstructive sleep apnea, respectively. There was a tight agreement between actigraphy and polysomnography in determining sleep efficiency (78.4 +/- 9.9 vs 78.8 +/- 13.4%), total sleep time (690 +/- 152 vs 690 +/- 154 epochs), and sleep latency (56.8 +/- 31.4 vs 43.3 +/- 45.4 epochs). While for most individuals the difference between the polysomnography and actigraphy was relatively small, for some there was a substantial disagreement. CONCLUSIONS: We conclude that this actigraphy algorithm provides a reasonably accurate estimation of sleep and wakefulness in normal subjects and patients with obstructive sleep apnea on an epoch-by-epoch basis. This simple method for assessment of total sleep time may provide a useful tool for the accurate quantification of obstructive sleep apnea in the home environment.
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| 2. |
- Liu, Bingbing, et al.
(author)
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Synthesis and characterization of single-walled nanotubes produced with Ce as catalyst
- 2000
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In: Molecular Materials: Molecular Crystals and Liquid Crystals Section C, vol. 13. - : Overseas Publishers Association N.V.. ; , s. 75-80
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Conference paper (peer-reviewed)abstract
- We have studied the effect of using rare-earth elements C (typically +4 oxide state) and Eu (typically +2 oxide state) together with nanometer Ni as catalysts to synthesize SWNT in high yield by arc evaporation. A black collar deposit containing mainly SWNT was formed in the presence of Ce/Ni while only nanometer carbon particles were formed using Eu/Ni, as identified by SEM, TEM and Raman spectra. The Raman spectra of our SWNT mats show difference from spectra shown in the literature in a low frequency range, indicating that our mats contain chiral tubes. The temperature dependent resistance of SWNT mats was also measured. A semiconducting behaviour was observed with a negative dR/dT and no resistance minimum from 2 to 350 K. The resistance follows a 2D variable range hopping behaviour.
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| 5. |
- Vidal, D., et al.
(author)
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Modelling coating structure development : Monte-Carlo deposition of particles with irregular shapes
- 2004
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In: Nordic Pulp and Paper Research Journal. - 0283-2631. ; 19:4, s. 420-427
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Journal article (peer-reviewed)abstract
- There is an increasing interest in enhancing coated paper performance by combining the unique properties of various pigments, i.e. developing multi-pigment coating formulations. An understanding of the synergy between pigments of different sizes and shapes is therefore becoming critical. The literature on this subject is rather empirical and fragmentary. In this report, we introduce an improved 3D Monte-Carlo deposition model to simulate coating structure development for irregularly shaped particles. The model relies on the minimization of the total energy of the particle system, which is defined as a sum of three terms: a pair interaction that accounts for collisional interactions, a gravitational potential energy, and a drag potential energy that takes into account the drainage rate of the colour. The model predicts that pigments with higher aspect ratios give a more porous structure and a smoother surface when applied at high solids content. Coating at low solids content (<45-55%) is shown to produce “looser” and more disordered structures, especially in the case of platelet pigments like clay. These results agree with practical and experimental observations. When blending clays with calcium carbonates, the model predicts the occurrence of maximum pore volume and surface micro-roughness at specific mixing ratios. The location of these maxima varies significantly with the particle’s aspect ratio, the relative size of the blended pigments, and the solids content of the suspension. With further experimental validation, this model has the potential of being used as a tool for designing and optimizing coating formulations.
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| 6. |
- Zou, X D, et al.
(author)
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TRICE - A program for reconstructing 3D reciprocal space and determining unit-cell parameters
- 2004
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In: Ultramicroscopy. - : Elsevier BV. - 0304-3991 .- 1879-2723. ; 98:2-4, s. 187-193
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Journal article (peer-reviewed)abstract
- A program system-Trice-for reconstructing the 3D reciprocal lattice from an electron diffraction tilt series is described. The unit-cell parameters can be determined from electron diffraction patterns directly by Trice. The unit cell can be checked and the lattice type and crystal system can be determined from the 3D reciprocal lattice. Trice can be applied to all crystal systems and lattice types.
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