- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Thickness-Dependent Swelling Behavior of Vapor-Deposited Smart Polymer Thin Films
摘要： In this contribution, the temperature-dependent swelling behavior of vapor-deposited smart polymer thin films is shown to depend on cross-linking and deposited film thickness. Smart polymers find application in sensor and actuator setups and are mostly fabricated on delicate substrates with complex nanostructures that need to be conformally coated. As initiated chemical vapor deposition (iCVD) meets these specific requirements, the present work concentrates on temperature-dependent swelling behavior of iCVD poly(N-isopropylacrylamide) thin films. The transition between swollen and shrunken state and the corresponding lower critical solution temperature (LCST) was investigated by spectroscopic ellipsometry in water. The films’ density in the dry state evaluated from X-ray reflectivity could be successfully correlated to the position of the LCST in water and was found to vary between 1.1 and 1.3 g/cm3 in the thickness range 30?330 nm. This work emphasizes the importance of insights in both the deposition process and mechanisms during swelling of smart polymeric structures.
关键词： X-ray reflectivity,spectroscopic ellipsometry,vapor-deposited,smart polymers,iCVD,LCST,film thickness,swelling behavior,cross-linking
更新于2025-09-11 14:15:04
-
Spectral Domain Optical Coherence Tomography Assessment of Macular and Optic Nerve Alterations in Patients with Glaucoma and Correlation with Visual Field Index
摘要： Introduction. To evaluate the sectorial thickness of single retinal layers and optic nerve using spectral domain optic coherence tomography (SD-OCT) and highlight the parameters with the best diagnostic accuracy in distinguishing between normal and glaucoma subjects at di?erent stages of the disease. Material and Methods. For this cross-sectional study, 25 glaucomatous (49 eyes) and 18 age-matched healthy subjects (35 eyes) underwent a complete ophthalmologic examination including visual ?eld testing. Sectorial thickness values of each retinal layer and of the optic nerve were measured using SD-OCT Glaucoma Module Premium Edition (GMPE) software. Each parameter was compared between the groups, and the layers and sectors with the best area under the receiver operating characteristic curve (AUC) were identi?ed. Correlation of visual ?eld index with the most relevant structural parameters was also evaluated. Results and Discussion. All subjects were grouped according to stage as follows: Controls (CTRL); Early Stage Group (EG) (Stage 1 + Stage 2); Advanced Stage Group (AG) (Stage 3 + Stage 4 + Stage 5). mGCL TI, mGCL TO, mIPL TO, mean mGCL, cpRNFLt NS, and cpRNFLt TI showed the best results in terms of AUC according classi?cation proposed by Swets (0.9 < AUC < 1.0). These parameters also showed signi?cantly di?erent values among group when CTRL vs EG, CTRL vs AG, and EG vs AG were compared. SD-OCT examination showed signi?cant sectorial thickness di?erences in most of the macular layers when glaucomatous patients at di?erent stages of the disease were compared each other and to the controls.
关键词： glaucoma,spectral domain optical coherence tomography,macular thickness,optic nerve,visual field index
更新于2025-09-11 14:15:04
-
LIGHT-CURING DISTANCE AND RESIN THICKNESS EFFECTS ON THE SHORTFIBER–REINFORCED RESIN COMPOSITES’ DEPTH OF CURE
摘要： This study evaluated the light-curing distance and resin thickness effects on the depth of cure of short fiber–reinforced resin composites (SFRCs). Methods: Fifteen SFRC specimens with a diameter of 6 mm and thickness of 4 mm were divided into groups (n=5) with light-curing distances of 0, 2, and 4 mm. Another 15 specimens with a diameter of 6 mm and thicknesses of 3, 4, and 5 mm (n=5) were subjected to a 0-mm light-curing distance. Microhardness tests were conducted using a Vickers hardness tester (load: 200 g; dwell time: 15 s), and the depth of cure was assessed by calculating the hardness ratio of the bottom to the top surface (%). Statistical tests included one-way analysis of variance (ANOVA) followed by Fisher’s LSD tests. Results: The depths of cure with 0-, 2-, and 4-mm light-curing distances were 79.0±0.7%, 77.0±0.6%, and 75.0±0.8%, while those with thicknesses of 3, 4, and 5 mm were 81.0±1.0%, 78.2±1.0%, and 34.4±2.0%, respectively. Significant differences (p<0.05) in the depth of cure were found in all groups. Conclusion: A depth of cure >80% was only attained with a 3-mm resin thickness and 0-mm light-curing distance.
关键词： Light-curing distance,Short fiber–reinforced resin composite,Depth of cure,Resin thickness
更新于2025-09-11 14:15:04
-
Optical coherence tomography angiography analysis of changes in the retina and the choroid after haemodialysis
摘要： The purpose of this study is to evaluate the effect of haemodialysis on perfused vessel density, choroidal thickness (CT), and retinal thickness in end-stage renal disease (ESRD) using swept-source optical coherence tomography angiography (SS-OCTA). We studied twenty-nine eyes of 29 ESRD patients by ophthalmologic examination and SS-OCTA before and after haemodialysis. The colour-coded perfusion density maps were generated and perfused vessel density was calculated. Changes in systemic and other ocular parameters such as retinal and choroidal thickness were measured and analysed. Total perfused vessel density decreased significantly after haemodialysis in the choriocapillaris; it was not significantly different in the superficial capillary plexus (SCP) and the deep capillary plexus (DCP). Total CT decreased significantly, but total retinal thickness was not significantly different. There was no significant correlation between choriocapillaris perfused vessel density and CT. The reduction in choriocapillaris perfused vessel density correlated with the decrease in systolic and mean arterial blood pressures. The decrease in CT correlated with the ultrafiltration volume. There were no significant systemic and ocular factors affecting change in retinal thickness and perfused vessel density of SCP and DCP. This is the first study to assess the effect of haemodialysis on blood flow changes using SS-OCTA; changes may be more prominent in the choroidal compared to the retinal layer.
关键词： angiography,choroidal thickness,haemodialysis,Optical coherence tomography,end-stage renal disease,perfused vessel density,retinal thickness
更新于2025-09-10 09:29:36
-
Effects of Cataract Extraction on the Outcomes of Automated Perimetry and Retinal Nerve Fiber Layer Thickness Measurements by Optical Coherence Tomography in Primary Angle Closure Glaucoma
摘要： Objective: To evaluate the effect of cataract extraction on both visual field and retinal nerve fiber layer thickness measurements in primary angle closure glaucoma (PACG) eyes. Methods: Retrospective cohort study on 30 PACG eyes underwent cataract extraction. Changes in RNFL thickness and visual field parameters including mean deviation (MD), visual field index (VFI) and pattern standard deviation (PSD) were analyzed within 6 months before and after cataract extraction. Results: Overall, MD (p=0.003) and VFI (p=0.004) improved significantly after cataract extraction, whereas PSD showed no significant change (p=0.6). In the 10 eyes with MD worse than -20 dB, mean MD improved by 3.4 ± 3.56 dB (from -24.36 ± 3.06 dB to -20.96 ± 5.06 dB, p=0.01) and mean VFI improved by 16.25 ± 15.66% (from 23.38 ± 9.65% to 39.63 ± 20.83%, p=0.02). PSD showed no significant change after cataract extraction (p=0.07). In the 20 eyes with MD better than -20 dB, MD and VFI also improved postoperatively, but the changes did not reach statistical significance: mean MD improved by 1.64 ± 3.65 dB (from -11.57 ± 5.57 dB to -9.92 ± 5.36 dB, p=0.05) whilst mean VFI improved by 4.57 ± 12.29% (from 74.95 ± 17.95% to 79.52 ± 17.26%, p=0.07). RNFL thickness did not show any significant changes after cataract extraction (p=0.13). Conclusions: Both MD and VFI improved after cataract extraction, especially in eyes with pre-operative MD worse than -20 dB. PSD and RNFL thickness showed no significant change after cataract extraction.
关键词： Perimetry,Visual field,Extraction,Retinal nerve fiber layer thickness,Optical coherence tomography,Primary angle closure glaucoma,Cataract
更新于2025-09-10 09:29:36
-
Directional, Horizontal Inhomogeneities of Cloud Optical Thickness Fields Retrieved from Ground-Based and Airborne Spectral Imaging
摘要： Clouds exhibit significant horizontal inhomogeneities of their optical and microphysical properties, which complicate their realistic representation in weather and climate models. In order to investigate the directional, horizontal structure of cloud inhomogeneities, two-dimensional (2D) horizontal fields of optical thickness of subtropical cirrus and Arctic stratus with a spatial resolution of <10 m are investigated. The cloud optical thickness fields were derived from downward (transmitted) solar spectral radiance measurements from the ground beneath four cirrus clouds, and upward (reflected) radiances measured from aircraft above ten Arctic stratus clouds. The data were collected during the two major field campaigns Clouds, Aerosol, Radiation, and tuRbulence in the trade wInd regime over BArbados (CARRIBA) and VERtical Distribution of Ice in Arctic clouds (VERDI). Scalar one-dimensional (1D) and 2D autocorrelation functions, as well as power spectral densities are derived from the retrieved τ fields. Decorrelation lengths and scale breaks are identified and used to characterize the size range of the inhomogeneities and their influence on three-dimensional (3D) radiative effects. These studies reveal that there are considerable directional cloud inhomogeneities along and across the prevailing cloud structures. Therefore it is not sufficient to quantify horizontal cloud inhomogeneities by scalar 1D inhomogeneity parameters; 2D parameters are necessarily required.
关键词： power spectral densities,spectral imaging,autocorrelation functions,scale breaks,cloud optical thickness,decorrelation lengths,horizontal inhomogeneities,3D radiative effects
更新于2025-09-10 09:29:36
-
Thickness Measurement and Three-Dimensional Structure Imaging of Oil Slick on Water by Optical Coherence Tomography
摘要： Spectral Domain Optical Coherence Tomography (SD-OCT) with 1300 nm wavelength is employed to detect three-dimensional (3-D) volumetric structure, surficial characteristic and thickness of oil slicks on water surface. The results show that petroleum slick possesses bigger diffusion area but much thinner than diesel slick at the same volume on water. Through reconstructing the thickness of oil slick by single-pixel optical intensity of SD-OCT structure image, the axial depth accuracies of reconstructed dataset image with 2.2 μm in petroleum slick and 2.6 μm in diesel slick were obtained, respectively. To our knowledge, it is the first time to obtain 3-D structure and surficial characteristic of oil slick on water by using SD-OCT imaging, and employing single-pixel optical intensity for reconstructing the thickness of oil slick with higher accuracy.
关键词： Oil slick,Reconstruction thickness,3-D image,SD-OCT
更新于2025-09-10 09:29:36
-
Foveal structure during the induction phase of anti-vascular endothelial growth factor therapy for occult choroidal neovascularization in age-related macular degeneration
摘要： Purpose: To evaluate the efficacy of monthly injections of aflibercept and ranibizumab on foveal structure after three months, for the treatment of occult choroidal neovascularization (CNV) in age-related macular degeneration (AMD). Methods: We retrospectively studied 103 eyes with treatment-na?ve neovascular AMD with occult and no classic CNV. Seventy-four of 103 eyes were treated with ranibizumab (intravitreal ranibizumab injection [IVR] group); 29 eyes were treated with aflibercept (intravitreal aflibercept injection [IAI] group). The best-corrected visual acuity and the retinal and choroidal structure at the fovea were evaluated using optical coherence tomography. Results: The total foveal thickness, the height of serous retinal detachments, and subfoveal choroidal thickness were compared with baseline, and the incidence of retinal pigment epithelial elevation significantly decreased in the IAI group compared with the IVR group. In contrast, the thickness of the sensory retina at the fovea significantly decreased in the IVR group when compared with the IAI group. The logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity improved more significantly in the IVR group (?0.085±0.164) than in the IAI group (?0.020±0.125) at 3 months (P=0.017). Conclusion: After intravitreal injection, aflibercept more rapidly reduced subretinal fluid and subfoveal choroidal thickness. In contrast, ranibizumab decreased the sensory retinal thickness compared with aflibercept. The responses of the retinal and choroidal tissue to these anti-VEGF agents may be different during the induction phase for eyes with occult CNV secondary to neovascular AMD.
关键词： occult,neovascular age-related macular degeneration,outer nuclear layer,aflibercept,retinal thickness,ranibizumab
更新于2025-09-10 09:29:36
-
Comparison of Reliability in Diabetic Macular Edema Estimates between Two Image Analysis Algorithms
摘要： Purpose: To evaluate segmentation reliability in diabetic macular edema (DME) estimates between a CirrusTM HD-OCT image analysis algorithm and an Iowa reference algorithm, which are an automatic segmentation software. Methods: Thirty eyes from 23 patients diagnosed with DME were included and underwent spectral-domain optical coherence scans (CirrusTM HD-OCT). Central foveal thickness (CFT) and ganglion cell layer-inner plexiform layer segmentation data were compared with those produced by the CirrusTM HD-OCT segmentation algorithm and Iowa reference algorithm. Measurement agreement was assessed using intraclass correlation (ICC) and segmentation errors were confirmed by 2 ophthalmologists. Results: The mean CFT in the 1-mm central area determined by the manufacturer-supplied Cirrus software and Iowa reference algorithm was 512.07 ± 182.35 μm and 476.53 ± 32.36 μm, respectively (p < 0.05). The mean paired difference was 35.53 ± 92.46 μm (ICC, 0.929). Segmentation errors were demonstrated in eyes with a CFT less than 400 μm, specifically for 45% of scans obtained by the Cirrus algorithm and 9% from the Iowa algorithm; in eyes with a CFT equal to or higher than 400 μm, the error rates were 95% and 42%, respectively. Conclusions: CFT measurement in eyes with diabetic macular edema using the Cirrus algorithm and Iowa algorithm showed relatively high degrees of agreement and significant correlation. In eyes with a CFT equal to or higher than 400 μm, the Iowa algorithm showed higher reliability in retinal segmentation than the Cirrus algorithm.
关键词： Reliability,Segmentation algorithm,Diabetic macular edema,Optical coherence tomography,Central foveal thickness
更新于2025-09-10 09:29:36
-
The Repeatability of Retinal Layer Thickness Measurements with Spectral-Domain Optical Coherence Tomography in Normal Eyes
摘要： Purpose: To evaluate the repeatability of retinal layer thickness measurements in normal eyes imaged using spectral domain optical coherence tomography (SD-OCT). Methods: Sixty-eight eyes of 34 healthy subjects were enrolled in this study. Imaging was performed 4 times using 9 × 9 mm macular scans with SD-OCT (RS 3000 Advance HD OCT, NIDEK, Gamagori, Japan) at the same visit by an experienced examiner. After automatic retinal segmentation (layering) in 5 layers, the thickness of each layer was calculated. Macular thickness of 9 Early Treatment of Diabetic Retinopathy Study (ETDRS)–like regions was obtained. Repeatability for each of the 9 subfield areas was calculated by their repeatability coefficients and intraclass correlation coefficients (ICCs). Results: There was no significant difference in average retinal thickness and each retinal layer thickness between all measurements acquired by the experienced examiner. The ICCs of retinal layer thickness ranged from 0.826 to 0.847 for the ganglion cell layer + inner plexiform layer, inner nuclear layer + outer plexiform layer and outer nuclear layer + external limiting membrane in the fovea. The ICCs were greater than 0.909 for the other intra-retinal layers in all 9 ETDRS subfield thickness between all measurement pairs. Conclusions: Excellent repeatability was observed for SD-OCT retinal segmented layer thickness measurements in healthy subjects.
关键词： Repeatability,Spectral domain optical coherence tomography,Retinal layer thickness,Automated segmentation,Intraclass correlation coefficients
更新于2025-09-10 09:29:36