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Infertility Diagnosis and Treatment
Published in Sujoy K. Guba, Bioengineering in Reproductive Medicine, 2020
In Contact Thermography temperature sensing is done using liquid crystals. Liquid crystals are materials so named because they have some mechanical properties similar to liquids and at the same time have optical properties shown by crystalline forms in solids. The optical properties include light scattering in symmetrical patterns and frequency selective reflection of light. The properties vary under the influence of temperature. When a film of liquid crystal is illuminated with white light spectral density of light reflected from different regions will depend upon the temperature conditions in that particular region and a color pattern indicative of the temperature of the underlying substrate is seen. Cholesteric liquid crystals are one class of liquid crystals. Cholesterol itself does not have a liquid phase and cholesteric compound are mixed together in specific proportions to manifest color sensitivity in specific ranges. For biological work where temperatures around 37°C are of interests a mixture of cholesteryl chloride, cholesteryl nonanoate and cholesteryl oleyl carbonate can give red (cold) to blue (hot) color change.
Predicting Stability in Rheologically Modified Systems
Published in Laba Dennis, Rheological Proper ties of Cosmetics and Toiletries, 2017
Recently, differential thermal analysis (DTA) has become a practical screen for structural changes in mixtures. Differential scanning calorimetry (DSC) is the form of DTA that is most widely applied, although some applications of differential volume have been fruitful. Differential calorimetry has identified isomorphs of triglycerides in creams, and liquid crystalline mesophases. DSC provides an excellent evaluation method for stress-induced changes, and can even provide an early warning for stability problems. It cannot, however, supplant accelerated stress testing. Phase transitions are easily identified in both quantitative heat energy (latent heat of melting) and temperature of phase change. Liquid crystal phases are easily identified this way.
Liquid Crystals as Drug Delivery Systems for Skin Applications
Published in Andreia Ascenso, Sandra Simões, Helena Ribeiro, Carrier-Mediated Dermal Delivery, 2017
Liquid crystals can be classified in lyotropic or thermotropic liquid crystalline phases when the formation of the systems is induced by the addition of a solvent or by temperature, respectively. For drug delivery purposes, the most used systems are the lyotropic liquid crystalline phases, which are formed by polar lipids in contact with water [2,4,5].
The Effects of Binocular Visual Function Training after Concomitant Exotropia Surgery
Published in Current Eye Research, 2023
Jing Chen, Jin Xu, Huili Jia, Jing He, Zhengyang Tao, Ping Huang, Huahong Zhong, Hongwei Deng
The advanced 4D digital strabismus correction system that the authors employed for in-hospital training was developed according to high-tech three-dimensional (3D) multi-dimensional digital new media technology, based on the cognitive theory of visual attention in modern neuropsychology, and the principle of the synaptic plasticity-change mechanism in neurobiology. It is an approach that includes deinhibition training, abnormal retina-corresponding training, a fusion perceptual function training system, and a 3D spatial perceptual function training system, enabling it to provide targeted, individualized, and quantitative training to maximize visual stimulation according to individual patient visual function status. Moreover, it can also quantitatively provide simultaneous perceptual training for perception fusion, particularly fusion function training using random-dot stereograms. Because it can accurately capture the breakpoint of binocular single vision, it has better operability and practicality for detecting and training the fusion function using random-dot stereograms. Finally, the use of polarized light and liquid-crystal switching stereo imaging technology can be maximized for the inspection and training of stereoscopic vision. Patients were trained according to the film content and the range of the Arcsecond. Interesting training games can be developed according to different levels of stereoscopic acuity, thereby providing a diversified range of training modes and short treatment times, which can greatly improve the treatment compliance of children.
Ocular lamellar crystalline gels for sustained release and enhanced permeation of resveratrol against corneal neovascularization
Published in Drug Delivery, 2021
Minshu Li, Xiang Yu, Lin Zhu, Yiguang Jin, Zhihong Wu
Lyotropic liquid crystals have recently attracted attention for mucosal drug delivery due to their long retention time at administrated sites and high permeability across biological barriers. Lyotropic liquid crystals have been used as transdermal delivery carriers for the treatment of skin diseases. Mitoxantrone-loaded cubic lyotropic liquid crystal gels have been fabricated for the topical treatment of melanomas (Yu et al., 2016) and capsaicin transdermal cubic crystal gels have been developed to alleviate skin inflammations (Peng et al., 2010). In our preliminary studies, cubic crystals with high viscosity and low resveratrol loading were not suitable for ocular resveratrol delivery. In contrast, lamellar liquid crystals, a type of lyotropic liquid crystals, have suitable fluidity, and high drug loading (Iwata et al., 2004). In this study, we used resveratrol-loaded ocular lamellar crystalline gel (ROLG) for the treatment of CNV.
Some observations on the liquid crystalline and gel behaviors of aqueous dispersions of a prodrug
Published in Drug Development and Industrial Pharmacy, 2019
Li Tao, Jinjiang Li, Swathi Pinamanenni, Krishnaswamy Raghavan
Formation of liquid crystalline phases (LCPs) by active pharmaceutical ingredients (APIs) has been previously reported, especially regarding their impact to drug product development [1–4]. Both thermotropic-sensitive to temperature and lyotropic-sensitive to solvent liquid crystals were discovered for pharmaceutical materials [1,5]. Thermotropic LCPs are usually formed from APIs under heating while lyotropic liquid crystalline phases appear when compounds are dissolved or suspended in solution [3]. Furthermore, lyotropic liquid crystalline (LLC) phases are frequently used for controlling the release of drugs. Examples include that propranolol hydrochloride dispersions (a smectic phase) are administered for treating cardiac symptom [6,7,8]. In particular, drug delivery systems with lamellar phases were reported in literature [9,10]. Mechanistically, formation of LLC phases is strongly influenced by both molecular properties of drugs and the solvent properties of the media dispersed [2,11].