Acrylate-based
photo-cross-linked poly(ε-caprolactone) (PCL)
tends to show low elongation and strength. Incorporation of osteo-inductive
hydroxyapatite (HAp) further enhances this effect, which limits its
applicability in bone tissue engineering. To overcome this, the thiol–ene
click reaction is introduced for the first time in order to photo-cross-link
PCL composites with 0, 10, 20, and 30 wt % HAp nanoparticles. It is
demonstrated that the elongation at break and ultimate strength increase
10- and 2-fold, respectively, when the photopolymerization mechanism
is shifted from a radical chain-growth (i.e., acrylate cross-linking)
toward a radical step-growth polymerization (i.e., thiol–ene
cross-linking). Additionally, it is illustrated that osteoblasts can
attach to and proliferate on the surface of the photo-cross-linked
PCL-HAp composites. Finally, the incorporation of HAp nanoparticles
is shown to reduce the ALP activity of osteoblasts. Overall, thiol–ene
cross-linked PCL-HAp composites can be considered as promising potential
materials for bone tissue engineering.
The use of high quality facemasks is indispensable in the light of the current COVID pandemic. This study proposes a fully automatic technique to design a face specific mask. Through the use of stereophotogrammetry, computer-assisted design and three-dimensional (3D) printing, we describe a protocol for manufacturing facemasks perfectly adapted to the individual face characteristics. The face specific mask was compared to a universal design of facemask and different filter container’s designs were merged with the mask body. Subjective assessment of the face specific mask demonstrated tight closure at the nose, mouth and chin area, and permits the normal wearing of glasses. A screw-drive locking system is advised for easy assembly of the filter components. Automation of the process enables high volume production but still allows sufficient designer interaction to answer specific requirements. The suggested protocol can be used to provide more comfortable, effective and sustainable solution compared to a single use, standardized mask. Subsequent research on printing materials, sterilization technique and compliance with international regulations will facilitate the introduction of the face specific mask in clinical practice as well as for general use.
Post-processing analysis can provide valuable information for diagnosis and planning of orbital disorders. This cross-sectional study aims to evaluate the reliability of semi-automatic, orbital fat volumetry using magnetic resonance imaging (MRI). Two observers assessed the orbital fat volume using a standard MRI protocol (3T, T1w sequence) in 12 orbits diagnosed with Graves' orbitopathy (GO) and 10 healthy control orbits. MRI and computed tomography (CT) based analysis were compared. Intra-observer variability was good (intraclass correlation coefficient (ICC) 0.88; 95% confidence interval (CI) [0.70, 0.95]) and interobserver agreement was moderate (ICC 0.55; 95% CI [À0.09, 0.81]), which corresponds to a mean percentage difference of 1.3% and 17.9% of the total orbital fat volume. Mean differences between MRI and CT measurements were, respectively, 1.1 cm 3 (P= 0.064, 95% CI [À0.20, 2.43]) and 1.4 cm 3 (P=0.016, 95% CI [0.21, 2.56]) for the control and the GO group. MRI volumetry was strongly correlated with CT (Pearson's r= 0.7, P<0.001). We conclude that orbital fat volumetry is feasible with a semi-automatic segmentation procedure and standard MRI protocol. Correlation with CT volumetry is good, but considerable bias may derive from observer variability and these errors should be taken into account for the purpose of volumetric analysis. Better definition of error sources may increase measurement accuracy.
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