Importance of the field-The advancement in material design and engineering has led to the rapid development of novel materials with increasing complexity and functions. Both non-degradable and degradable polymers have found wide applications in the controlled delivery field. Studies on drug release kinetics provide important information into the function of material systems. To elucidate the detailed transport mechanism and the structure-function relationship of a material system, it is critical to bridge the gap between the macroscopic data and the transport behavior at the molecular level.Areas covered in this review-The structure and function information of selected nondegradable and degradable polymers have been collected and summarized from literatures published after 1990s. The release kinetics of selected drug compounds from various material systems will be discussed in case studies. Recent progresses in the mathematical models based on different transport mechanisms will be highlighted.What the reader will gain-This article aims to provide an overview of structure-function relationships of selected non-degradable and degradable polymers as drug delivery matrices.Take home message-Understanding the structure-function relationship of the material system is key to the successful design of a delivery system for a particular application. Moreover, developing complex polymeric matrices requires more robust mathematical models to elucidate the solute transport mechanisms.
Transformation of greenhouse gas CO2 and renewable H2 into fuels and commodity chemicals is recognized as a promising route to store fluctuating renewable energy. Although several C1 chemicals, olefins, and gasoline have been successfully synthesized by CO2 hydrogenation, selective conversion of CO2 and H2 into aromatics is still challenging due to the high unsaturation degree and complex structures of aromatics. Here we report a composite catalyst of ZnAlOx and H-ZSM-5 which yields high aromatics selectivity (73.9%) with extremely low CH4 selectivity (0.4%) among the carbon products without CO. Methanol and dimethyl ether, which are synthesized by hydrogenation of formate species formed on ZnAlOx surface, are transmitted to H-ZSM-5 and subsequently converted into olefins and finally aromatics. Furthermore, 58.1% p-xylene in xylenes is achieved over the composite catalyst containing Si-H-ZSM-5. ZnAlOx&H-ZSM-5 suggests a promising application in manufacturing aromatics from CO2 and H2.
Abstract-Endothelial nitric oxide synthase (eNOS) plays a central role in maintaining cardiovascular homeostasis by controlling NO bioavailability. The activity of eNOS in vascular endothelial cells (ECs) largely depends on posttranslational modifications, including phosphorylation. Because the activity of AMP-activated protein kinase (AMPK) in ECs can be increased by multiple cardiovascular events, we studied the phosphorylation of eNOS Ser633 by AMPK and examined its functional relevance in the mouse models. Shear stress, atorvastatin, and adiponectin all increased AMPK Thr172 and eNOS Ser633 phosphorylations, which were abolished if AMPK was pharmacologically inhibited or genetically ablated. The constitutively active form of AMPK or an AMPK agonist caused a sustained Ser633 phosphorylation. Expression of gain-/loss-of-function eNOS mutants revealed that Ser633 phosphorylation is important for NO production. The aorta of AMPK␣2 Ϫ/Ϫ mice showed attenuated atorvastatin-induced eNOS phosphorylation. Nano-liquid chromatography/tandem mass spectrometry (LC/MS/MS) confirmed that eNOS Ser633 was able to compete with Ser1177 or acetyl-coenzyme A carboxylase Ser79 for AMPK␣ phosphorylation. Nano-LC/MS/MS confirmed that eNOS purified from AICAR-treated ECs was phosphorylated at both Ser633 and Ser1177. Our results indicate that AMPK phosphorylation of eNOS Ser633 is a functional signaling event for NO bioavailability in ECs.
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