interferometry
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The aim of this study is to consider the relevance of in situ measurements of bovine serum film thickness in the optical test device that could be related to the function of the artificial hip joint. It is mainly focussed on the effect of the hydrophobicity or hydrophilicity of the transparent surface and the effect of its geometry. Film thickness measurements were performed using ball-on-disc and lens-on-disc configurations of optical test device as a function of time. Chromatic interferograms were recorded with a high-speed complementary metal-oxide semiconductor digital camera and evaluated with thin film colorimetric interferometry. It was clarified that a chromium layer covering the glass disc has a hydrophobic behaviour which supports the adsorption of proteins contained in the bovine serum solution, thereby a thicker lubricating film is formed. On the contrary, the protein film formation was not observed when the disc was covered with a silica layer having a hydrophilic behaviour. In this case, a very thin lubricating film was formed only due to the hydrodynamic effect. Metal and ceramic balls have no substantial effect on lubricant film formation although their contact surfaces have relatively different wettability. It was confirmed that conformity of contacting surfaces and kinematic conditions has fundamental effect on bovine serum film formation. In the ball-on-disc configuration, the lubricant film is formed predominantly due to protein aggregations, which pass through the contact zone and increase the film thickness. In the more conformal ball-on-lens configuration, the lubricant film is formed predominantly due to hydrodynamic effect, thereby the film thickness is kept constant during measurement.
- MeSH
- adsorpce MeSH
- biomechanika MeSH
- hydrofobní a hydrofilní interakce MeSH
- interferometrie metody MeSH
- kyčelní protézy * MeSH
- lubrikanty chemie MeSH
- sérum chemie MeSH
- skot MeSH
- smáčivost MeSH
- testování materiálů metody MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Úvod: Cílem naší práce bylo srovnat výsledky pachymetrie a keratometrie rohovky na třech různých oftalmologických přístrojích s touto funkcí a zjistit, zda jsou tyto přístroje v praxi vzájemně zastupitelné. Metodika: Do studovaného souboru bylo zařazeno 43 zdravých osob s normálním očním nálezem (29 žen a 14 mužů, průměrný věk 25 let ± 3,5). Centrální tloušťka rohovky (CCT) byla měřena na přístroji Pentacam HR, Allegro BioGraph a pomocí ultrazvukové pachymetrie na přístroji OcuScan RxP. Zakřivení rohovky ve dvou hlavních meridiánech (K1, K2) bylo měřeno na přístrojích Pentacam HR, Allegro BioGraph a pomocí automatického keratometru. Výsledky: Průměrný rozdíl v hodnotě K1 mezi Biographeem a autokeratometrem byl 0,01 ± 0,31 D, mezi BioGraphem a Pentacamem 0,06 ± 0,23 D a mezi autokeratometrem a Pentacamem 0,05 ± 0,34 D. Průměrný rozdíl v hodnotě K2 mezi BioGraphem a autokeratometrem byl 0,29 ± 0,45 D, mezi BioGraphem a Pentacamem 0,11 ± 0,28 D a mezi autokeratometrem a Pentacamem 0,19 ± 0,44 D. Zjištěné rozdíly v keratometrii byly ve všech případech statisticky významné (p < 0,05). Průměrný rozdíl v CCT mezi BioGraphem a ultrazvukem byl 4,57 ± 7,84 μm, mezi BioGraphem a Pentacamem 4,33 ± 7,55 μm a mezi ultrazvukem a Pentacamem 8,90 ± 7,49 μm. Rozdíly v tloušťce rohovky byly rovněž statisticky významné (p < 0,05). Závěr: Podle našich výsledků se mohou hodnoty keratometrie a CCT mezi testovanými přístroji významně lišit a nejsou tedy v praxi vzájemně zastupitelné.
Introduction: The aim of our study was to compare keratometry and central corneal thickness measurements obtained with three different ophthalmic devices and to decide if they can be used interchangeably in clinical practice. Methods: 43 healthy persons were included in the study (29 women and 14 men, average age 25 ± 3.5 years). Central corneal thickness (CCT) was measured with the Scheimpflug HR imaging system (Pentacam), Allegro BioGraph and with ultrasound pachymetry (RXP OcuScan). Keratometry in two main meridians of the cornea (K1, K2) was measured with Pentacam, Allegro BioGraph and automated keratometry. Results: The mean difference in K1-readings was 0.01 ± 0.31 D for BioGraph vs. automated keratometry, 0.06 ± 0.23 D for BioGraph vs. Pentacam and 0.05 ± 0.34 D for automated keratometry and Pentacam. The mean difference in K2-readings was 0.29 ± 0.45 D for BioGraph vs. automated keratometry, 0.11 ± 0.28 D for BioGraph vs. Pentacam and 0.19 ± 0.44 D for automated keratometry and Pentacam. The interdevice differences were in all cases statistically significant (p < 0.05). The mean difference in CCT was 4.57 ± 7.84 μm for BioGraph vs. ultrasound, 4.33 ± 7.55 μm for BioGraph vs. Pentacam and 8.90 ± 7.49 μm for ultrasound vs. Pentacam. The interdevice differences in CCT were also statistically significant (p < 0.05). Conclusion: Our results suggest that the measurements of keratometry and CCT may differ significantly between the tested machines and therefore should not be used interchangeably in clinical practice.
- Klíčová slova
- CCT, Pentacam, BioGraph,
- MeSH
- dospělí MeSH
- interferometrie přístrojové vybavení využití MeSH
- lidé MeSH
- odchylka pozorovatele MeSH
- reprodukovatelnost výsledků MeSH
- rohovka anatomie a histologie patologie MeSH
- rohovková topografie metody přístrojové vybavení statistika a číselné údaje MeSH
- ultrasonografie metody přístrojové vybavení MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- srovnávací studie MeSH
Principles of coherent and non-coherent double exposure Speckle photography are presented with evaluation of shift changes in continuous and discrete areas. The aim of this work is to demonstrate that this computer method can be also employed in medical research. It may be transformed for the study of small deformations of the specimens of lumbar spines during applications of different physical strains.•Incoherent computer speckle interferometry was used to visualize small changes in the assessment of lumbar spine surgical fixation.•Vertebral movement is contactless monitored by two cheap CCD cameras and evaluated using computer technology.•The results obtained were verified on a cadaveric sample of human spine.
- Publikační typ
- časopisecké články MeSH
