A novel pH-sensitive hydrogel system consisting of poly(methacrylic acid-g-ethylene glycol) (P(MAA-g-EG)) and acryloyl group modified-cholesterol-bearing pullulan (CHPOA) nanogels was developed for the controlled delivery of an anticonvulsant drug, pregabalin (PGB). Here, the hydrophilic hydrogel network provides the pH-sensitive swelling behavior, whereas nanogel components form separate reservoirs for the delivery of drugs with different hydrophobicities. These nanocarrier-integrated hybrid gels were synthesized through both surface-initiated and bulk photopolymerization approaches. The swelling and drug release behavior of these pH-responsive hydrogels synthesized by different photopolymerization approaches at visible and UV light wavelenghts were studied at acidic and basic pH values. Nanogel-integrated hydrogels exhibited higher swelling behavior compared to plain hydrogels in reversible swelling experiments. Similarly, the presence of nanogels in hydrogel network enhanced the loading and release percentages of PGB and the release was analyzed to describe the mode of transport through the network. In vitro cytotoxicity assay suggests that hydrogels in altered groups are nontoxic. This is the first report about the visible light-induced synthesis of a pH-responsive network incorporated CHPOA nanogels. Responsive and multifunctional properties of this system could be used for pH-triggered release of therapeutic molecules for clinical applications.

: Temperature heavily affects the behavior of any energy storage chemistries. In particular, lithium-ion batteries (LIBs) play a significant role in almost all storage application fields, including Electric Vehicles (EVs). Therefore, a full comprehension of the influence of the temperature on the key cell components and their governing equations is mandatory for the effective integration of LIBs into the application. If the battery is exposed to extreme thermal environments or the desired temperature cannot be maintained, the rates of chemical reactions and/or the mobility of the active species may change drastically. The alteration of properties of LIBs with temperature may create at best a performance problem and at worst a safety problem. Despite the presence of many reports on LIBs in the literature, their industrial realization has still been difficult, as the technologies developed in different labs have not been standardized yet. Thus, the field requires a systematic analysis of the effect of temperature on the critical properties of LIBs. In this paper, we report a comprehensive review of the effect of temperature on the properties of LIBs such as performance, cycle life, and safety. In addition, we focus on the alterations in resistances, energy losses, physicochemical properties, and aging mechanism when the temperature of LIBs are not under control.

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Rendering tactile effects on a touch screen via electrovibration has many potential applications. However, our knowledge on tactile perception of change in friction and the underlying contact mechanics are both very limited. In this study, we investigate the tactile perception and the contact mechanics for a step change in friction under electrovibration during a relative sliding between a finger and the surface of a capacitive touchscreen. First, we conduct magnitude estimation experiments to investigate the role of normal force and sliding velocity on the perceived tactile intensity for a step increase and decrease in friction, called rising friction (RF) and falling friction (FF). To investigate the contact mechanics involved in RF and FF, we then measure the frictional force, the apparent contact area, and the strains acting on the fingerpad during sliding at a constant velocity under three different normal loads using a custom-made experimental set-up. The results show that the participants perceived RF stronger than FF, and both the normal force and sliding velocity significantly influenced their perception. These results are supported by our mechanical measurements; the relative change in friction, the apparent contact area, and the strain in the sliding direction were all higher for RF than those for FF, especially for low normal forces. Taken together, our results suggest that different contact mechanics take place during RF and FF due to the viscoelastic behavior of fingerpad skin, and those differences influence our tactile perception of a step change in friction.