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Seaweeds as Sustainable Sources for Food Packaging
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Y. S. M. Senarathna, I. Wickramasinghe, S. B. Navaratne
Alginate-based films exhibit good flexibility, transparency, gel formation capability with low water vapor and oxygen permeability (Shahabi-Ghahfarrokhi et al. 2020; Santos et al. 2021). Along with better organoleptic properties of films formulated with alginates such as relatively good taste and odorless properties, it makes more applicable in edible packaging (Puscaselu et al. 2019). However, relatively lower mechanical strength, thermal stability, high water sensitivity and non-antibacterial properties of alginate films make its packaging applications limited (Hou et al. 2019; Chen et al. 2021).
The Delivery of Oxygen to the Myocardium
Published in Samuel Sideman, Rafael Beyar, Analysis and Simulation of the Cardiac System — Ischemia, 2020
Carl A. Goresky, Colin P. Rose
Do you think that oxygen permeability may be a rate-limiting factor under extreme conditions? The other question relates to heterogeneity. Is there any evidence to suggest heterogeneity in the permeability or transport of oxygen?
Placental Nutrient Metabolism and Transport
Published in Emilio Herrera, Robert H. Knopp, Perinatal Biochemistry, 2020
The regulation of nutrient uptake and transfer across the placenta by uterine and/or umbilical blood flow is dependent primarily on the placental permeability of each substrate and secondarily on the interaction between substrates.5 With respect to permeability, substrates such as water and oxygen to which the placenta is freely permeable are dependent largely on blood flow to maintain their supply and thus rate of placental uptake and transfer. Such substrates are subject to flow-limited clearance. In the nonstressed, nonanesthetized pregnant sheep, Wilkening, et al. have shown that placental oxygen transfer to the fetus is curvilinearly related to uterine blood flow and that a significant reduction in placental oxygen transfer does not occur until uterine flow is much less than 50% below normal (Figure 13).155 In other words, in spite of major decreases in oxygen delivery, the transplacental driving force (which is the transplacental PO2 gradient) and placental oxygen permeability are sufficiently large enough that transfer is maintained.
Efficacy of two silicone-hydrogel bandage contact lenses after corneal crosslinking
Published in Clinical and Experimental Optometry, 2021
Deniz Ozarslan Ozcan, Sait Coskun Ozcan
Corneal epithelial healing is often supported with the use of bandage contact lenses in clinical practice. A constant supply of oxygen is required to ensure the health and repair of the corneal epithelium. Extended wear contact lenses should have a value of approximately 125 oxygen transmissibility (Dk/t) to prevent corneal anoxia.16 SiH contact lenses provide a high Dk/t with a range of 110 to 175 due to their silicone component content. Soft lenses have beneficial properties such as covering the entire corneal surface and providing patient comfort with their soft structure. In addition to these properties considerably high oxygen permeability is the most important advantage of the silicone hydrogel lenses in therapeutic use. Taneri et al.17 showed that soft contact lenses had clinically meaningful therapeutic effects on epithelial healing, pain perception, visual recovery and haze formation after PRK.
Novel daily disposable therapeutic contact lenses based on chitosan and regenerated silk fibroin for the ophthalmic delivery of diclofenac sodium
Published in Drug Delivery, 2020
Rachasit Jeencham, Manote Sutheerawattananonda, Saowaluk Rungchang, Waree Tiyaboonchai
The CS/RSF films were prepared following the optimum condition in our previous study (Jeencham et al., 2019). The resulting CS/RSF films have met the material standards for daily disposable contact lenses requirement. The films possessed smooth surface with a high visible light transparency (> 90%) and high water content (59–65% by weight). They were also easy to handle with Young’s modulus and elongation at break in the range of 6.4–7.2 MPa and 70–100%, respectively, and showed no degradation in STF containing lysozyme for 24 h. The films also showed high ion permeability of 11 × 10−3 mm2/min and oxygen permeability of 22–26 Barrers. Thus we further explored the possibility of using CS/RSF films as biomaterials for contact lenses based ophthalmic delivery of diclofenac sodium.
Graft versus host disease: a pediatric perspective
Published in Expert Review of Ophthalmology, 2019
Simon SM Fung, Uri Elbaz, Kamiar Mireskandari, Asim Ali
Therapeutic contact lenses are a useful tool in reducing friction-related pain and evaporation from the inflamed ocular surface. Soft silicone hydrogel lenses have high oxygen permeability, and can be used as bandage contact lenses since they can be worn over an extended period of time [29]. Rigid gas permeable scleral lenses, including the Prosthetic Replacement of Ocular Surface Ecosystem (PROSE, BostonSight, Needham, MA), provide a tear reservoir in front of the corneal and conjunctival surfaces. Therefore, the ocular surface is protected from physical trauma and desiccation and is constantly lubricated. Any irregularities of the ocular surface could also be smoothened over by the tear reservoir, enhancing visual function [29,68,69]. Magro and colleagues studied the use of scleral contact lenses in 60 patients with severe chronic oGVHD, with the youngest being 6 years old [69]. Scleral contact lenses helped to significantly improve patients’ OSDI, best corrected visual acuity (BCVA), and corneal fluorescein staining. The authors’ experience is similarly positive. However, scleral lenses are relatively expensive and fitting expertise is limited to a number of specialty centers.