Attractive System Research Articles

Enhancing Efficiency of Low-Grade Heat Harvesting by Structural Vibration Entropy in Thermally Regenerative Electrochemical Cycles.

The majority of waste-heat energy exists in the form of low-grade heat (<100°C), which is immensely difficult to convert into usable energy using conventional energy-harvesting systems. Thermally regenerative electrochemical cycles (TREC), which integrate battery and thermal-energy-harvesting functionalities, have been considered an attractive system for low-grade heat harvesting. Herein, we investigate the role of structural vibration modes in enhancing the efficacy of TREC systems. We analyze how changes in bonding covalency, influenced by the amount of structural water molecules, impact the vibration modes. We discover that even small amounts of water molecules can induce the A1g stretching mode of cyanide ligands with strong structural vibration energy, which significantly contributes to a larger temperature coefficient (ɑ) in a TREC system. Leveraging these insights, we have designed and implemented a highly efficient TREC system using a sodium-ion-based aqueous electrolyte. Our study provides valuable insights into the potential of TREC systems, offering a deeper understanding of the intrinsic properties of Prussian Blue analogues (PBAs) regulated by structural vibration modes. These insights open up new possibilities for enhancing the energy-harvesting capabilities of TREC systems. This article is protected by copyright. All rights reserved.

Exploring multivalent protein-glycosensitizer interaction with phenalenone derivatives in mixed micelles

Carbohydrates are involved in several biological processes, and they have been widely used in several technological applications. Carbohydrate-based surfactants have low toxicity, and they are environmental friendly, however, their physicochemical properties restrict their use in potential applications. Mixed micelles are an attractive model system to use for carbohydrate–based surfactants since their physical properties may be easily modulated with simple changes in the surfactants mixture ratio.In this study, we design a mixed micelle system composed by new synthesized glycolipids bearing a photosensitizer in their hydrophobic moiety. We hypothesize that this system would have two main functions a) singlet oxygen generation and b) multivalent capability to interact with lectins. These combined capabilities will permit the generation of the short-lived excited oxygen neighboring the targets to be oxidized.In this design, non-ionic mixed micelles were used to modify the interfacial properties and to improve the solubility in water of the synthesized glycosensitizers.In summary, our results show that both glycolipids retain their capability to generate singlet oxygen in homogeneous media and the mixed micelles behave as an adequate multivalent system to interact with Con A. We provide a promising system to be successfully employed in antibacterial photodynamic therapy.

Chitosan-based hydrogel system for efficient removal of Cu[II] and sustainable utilization of spent adsorbent as a catalyst for environmental applications

The growing requirement for clean potable water requires sustainable methods of eliminating heavy metal ions and other organic contaminants. Herein, we synthesized a novel dual-purpose magnetically separable chitosan-based hydrogel system (CSGO-R@IO) that can efficiently remove toxic Cu2+ pollutants from water. FT-IR, XRD, SEM-EDX, VSM, XPS analyses were used to characterize the synthesized hydrogel. The CSGO-R@IO hydrogel showed high swelling capacity (1036.06 %), prominent adsorption capacity for Cu2+ ions (119.5 mg/g), and good recyclability up to four cycles. The adsorption data of Cu+2 ions on hydrogel fitted better to the Langmuir isotherm model (R2 = 0.9942), indicating spontaneous monolayer adsorption of Cu2+ ions on a homogenous surface. The adsorption kinetic studies fitted better with the pseudo-second-order model (R2 = 0.9992), suggesting that the adsorption process was controlled by chemisorption. We also showed a sustainable way to convert harmful Cu2+ pollutants into valuable Cu nanoparticles for catalysis, and Cu nanoparticles loaded hydrogel (CSGO-R@IO/Cu) had high catalytic activity. Hence, building attractive multipurpose hydrogel systems will give us new ideas about how to design and use new adsorbents to clean water in real life. They will also help in recycle metals (copper and maybe others) to conserve resources.

Polysaccharide-based (kappa carrageenan/carboxymethyl chitosan) nanofibrous membrane loaded with antifibrinolytic drug for rapid hemostasis- in vitro and in vivo evaluation

This work aimed to establish a novel membrane consisting of hemostatic polysaccharides, kappa-carrageenan (KC), and carboxymethyl chitosan (CMC) in tandem with polyvinyl alcohol that spun together as a matrix and loaded with tranexamic acid (TXA) as antifibrinolytic agent for further coagulation effect during and after oral surgeries. The electrospinning of KC was done for the first time and in comparison of CMC has better hemostatic efficacy. The effect of the hemostat was investigated by its surface morphology (SEM), FTIR/ATR analysis, swelling behavior in both PBS and blood, hydrophilicity, porosity, mechanical properties, and cumulative release rate. The effect of materials and the drug concentration ratio were considered. The effect of acetic acid percent in aqueous solutions of CMC/PVA and KC/PVA on morphology was investigated. The cell culture assay showed that all membranes interacted well (98 %) with fibroblast cells attached and grown on the fabricated substrate. Furthermore, the membranes are evaluated by clotting time, whole blood clotting, hemocompatibility, and platelet and RBC adhesion tests. Also, the hemostatic performance of the membrane was analyzed in vivo, using the tail and liver bleeding model in rats.Therefore, TXA loading into CMC and KC dressing could be an attractive hemostatic system for various clinical applications.

Intrinsic vacancy in 2D defective semiconductor In2S3 for artificial photonic nociceptor

It is crucial to develop an advanced artificially intelligent optoelectronic information system that accurately simulates photonic nociceptors like the activation process of a human visual nociceptive pathway. Visible light reaches the retina for human visual perception, but its excessive exposure can damage nearby tissues. However, there are relatively few reports on visible light–triggered nociceptors. Here, we introduce a two-dimensional natural defective III–VI semiconductor β-In2S3 and utilize its broad spectral response, including visible light brought by intrinsic defects, for visible light–triggered artificial photonic nociceptors. The response mode of the device, under visible light excitation, is very similar to that of the human eye. It perfectly reproduces the pain perception characteristics of the human visual system, such as ‘threshold,’ ‘relaxation,’ ‘no adaptation’, and ‘sensitization’. Its working principle is attributed to the mechanism of charge trapping associated with the intrinsic vacancies in In2S3 nanosheets. This work provides an attractive material system (intrinsic defective semiconductors) for broadband artificial photonic nociceptors.

Graphene quantum dots as sulfiphilic and lithiophilic mediator toward high stability and durable life lithium-sulfur batteries

The development of lithium-sulfur (Li-S) battery as one of the most attractive energy storage systems among lithium metal batteries is seriously hindered by low sulfur utilization, poor cycle stability and uneven redeposition of Li anode. It is necessary to propose strategies to address the problems as well as improve the electrochemical performance. One of the effective solutions is to improve the sulfiphilicity of sulfur cathode and the lithiophilicity of the Li anode. Herein, we reported that a synergistic functional separator (graphene quantum dots (GQDs)-polyacrylonitrile (PAN) @polypropylene (PP) separator) improved the electrochemical activity of sulfur cathode as well as the stability of Li anode. GQDs induced uniform Li+ nucleation and deposition, which slowed down the passivation of Li anode and avoided short-circuit. Further, three-dimensional network constructed by electrospinning nanofibers and the polar functional groups of GQDs could both effectively inhibit the shuttle of LiPSs and improve the sulfur utilization. The stability of Li-S battery was improved by the synergistic effect. In addition, GQDs and electrospinning nanofibers protector increased lifetime of separators. Benefiting from the unique design strategy, Li//Li symmetric battery with GQDs-PAN@PP separators exhibited stably cycling for over 600 h. More importantly, the Li-S full batteries based GQDs-PAN@PP separators enabled high stability and desirable sulfur electrochemistry, including high reversibility of 558.09 mA h g−1 for 200 cycles and durable life with a low fading rate of 0.075% per cycle after 500 cycles at 0.5 C. Moreover, an impressive areal capacity of 3.23 mA h cm−2 was maintained under high sulfur loading of 5.10 mg cm−2. This work provides a new insight for modification separator to improve the electrochemical performance of Li-S/Li metal batteries.

An Extended Membrane System with Monodirectional Tissue-like P Systems and Enhanced Particle Swarm Optimization for Data Clustering

In order to establish a highly efficient P system for resolving clustering problems and overcome the computation incompleteness and implementation difficulty of P systems, an attractive clustering membrane system, integrated with enhanced particle swarm optimization (PSO) based on environmental factors and crossover operators and a distributed parallel computing model of monodirectional tissue-like P systems (MTP), is constructed and proposed, which is simply named ECPSO-MTP. In the proposed ECPSO-MTP, two kinds of evolution rules for objects are defined and introduced to rewrite and modify the velocity of objects in different elementary membranes. The velocity updating model uses environmental factors based on partitioning information and randomly replaces global best to improve the clustering performance of ECPSO-MTP. The crossover operator for the position of objects is based on given objects and other objects with crossover probability and is accomplished through the hybridization of the global best of elementary membranes to reject randomness. The membrane structure of ECPSO-MTP is abstracted as a network structure, and the information exchange and resource sharing between different elementary membranes are accomplished by evolutional symport rules with promoters for objects of MTP, including forward and backward communication rules. The evolution and communication mechanisms in ECPSO-MTP are executed repeatedly through iteration. At last, comparison experiments, which are conducted on eight benchmark clustering datasets from artificial datasets and the UCI Machine Learning Repository and eight image segmentation datasets from BSDS500, demonstrate the effectiveness of the proposed ECPSO-MTP.

Experimental and Computational Mechanisms that Govern Long-Term Stability of CO2-Adsorbed ZIF-8-Based Porous Liquids.

Porous liquids (PLs) based on the zeolitic imidazole framework ZIF-8 are attractive systems for carbon capture since the hydrophobic ZIF framework can be solvated in aqueous solvent systems without porous host degradation. However, solid ZIF-8 is known to degrade when exposed to CO2 in wet environments, and therefore the long-term stability of ZIF-8-based PLs is unknown. Through aging experiments, the long-term stability of a ZIF-8 PL formed using the water, ethylene glycol, and 2-methylimidazole solvent system was systematically examined, and the mechanisms of degradation were elucidated. The PL was found to be stable for several weeks, with no ZIF framework degradation observed after aging in N2 or air. However, for PLs aged in a CO2 atmosphere, formation of a secondary phase occurred within 1 day from the degradation of the ZIF-8 framework. From the computational and structural evaluation of the effects of CO2 on the PL solvent mixture, it was identified that the basic environment of the PL caused ethylene glycol to react with CO2 forming carbonate species. These carbonate species further react within the PL to degrade ZIF-8. The mechanisms governing this process involves a multistep pathway for PL degradation and lays out a long-term evaluation strategy of PLs for carbon capture. Additionally, it clearly demonstrates the need to examine the reactivity and aging properties of all components in these complex PL systems in order to fully assess their stabilities and lifetimes.

Cytotoxic T Lymphocytes Control Growth of B16 Tumor Cells in Collagen-Fibrin Gels by Cytolytic and Non-Lytic Mechanisms.

Cytotoxic T lymphocytes (CTLs) are important in controlling some viral infections, and therapies involving the transfer of large numbers of cancer-specific CTLs have been successfully used to treat several types of cancers in humans. While the molecular mechanisms of how CTLs kill their targets are relatively well understood, we still lack a solid quantitative understanding of the kinetics and efficiency by which CTLs kill their targets in vivo. Collagen-fibrin-gel-based assays provide a tissue-like environment for the migration of CTLs, making them an attractive system to study T cell cytotoxicity in in vivo-like conditions. Budhu.et al. systematically varied the number of peptide (SIINFEKL)-pulsed B16 melanoma cells and SIINFEKL-specific CTLs (OT-1) and measured the remaining targets at different times after target and CTL co-inoculation into collagen-fibrin gels. The authors proposed that their data were consistent with a simple model in which tumors grow exponentially and are killed by CTLs at a per capita rate proportional to the CTL density in the gel. By fitting several alternative mathematical models to these data, we found that this simple "exponential-growth-mass-action-killing" model did not precisely describe the data. However, determining the best-fit model proved difficult because the best-performing model was dependent on the specific dataset chosen for the analysis. When considering all data that include biologically realistic CTL concentrations (E≤107cell/mL), the model in which tumors grow exponentially and CTLs suppress tumor's growth non-lytically and kill tumors according to the mass-action law (SiGMA model) fit the data with the best quality. A novel power analysis suggested that longer experiments (∼3-4 days) with four measurements of B16 tumor cell concentrations for a range of CTL concentrations would best allow discriminating between alternative models. Taken together, our results suggested that the interactions between tumors and CTLs in collagen-fibrin gels are more complex than a simple exponential-growth-mass-action killing model and provide support for the hypothesis that CTLs' impact on tumors may go beyond direct cytotoxicity.

Assessing passenger preferences for Bus Rapid Transit characteristics: A discrete choice experiment among current and potential Dutch passengers

To gain ridership, bus services need to offer more than just high frequencies. An attractive system design for Bus Rapid Transit (BRT) is a result of various configurational choices concerning infrastructure, rolling stock and operations. To find out which configurations are preferred by potential and current passengers, a Discrete Choice Experiment was carried out in The Netherlands. For this study, eight BRT characteristics were included. Results (n = 1019) show that four characteristics are valued the most: frequency, service hours, reliability and stop spacing. The attractiveness of three different service formulas or configurations is evaluated. The more conventional bus configuration is preferred by the majority of the respondents. However, a considerable amount (25%) of respondents that prefer this configuration does not consider using this service formula. Configurations that either address offering more passenger comfort or higher capacity, do seem to be attractive to distinct passenger segments who are more likely to actually use the service. These appealing BRT configurations address different types of passenger segments and therefore could coexist on certain routes.

Rational Design of a High-Loading Polysulfide Cathode and a Thin-Lithium Anode for Developing Lean-Electrolyte Lithium-Sulfur Full Cells.

Lithium-sulfur cells are attractive energy-storage systems because of their high energy density and the electrochemical utilization rates of the high-capacity lithium-metal anode and the low-cost sulfur cathode. The commercialization of high-performance lithium-sulfur cells with high discharge capacity and cyclic stability requires the optimization of practical cell-design parameters. Herein, a carbon structural material composed of a carbon nanotube skeleton entrapping conductive graphene is synthesized as an electrode substrate. The carbon structural material is optimized to develop a high-loading polysulfide cathode with a high sulfur loading capacity (6-12mg cm-2 ), rate performance (C/10-C/2), and cyclic stability for 200 cycles. A thin lithium anode based on the carbon structural material is developed and exhibits long lithium stripping/plating stability for ≈2500h with a lithium-ion transference number of 0.68. A lean-electrolyte lithium-sulfur full cell with a low electrolyte-to-sulfur ratio of 6µL mg-1 is constructed with the designed high-loading polysulfide cathode and the thin lithium anode. The integration of all the critical cell-design parameters endows the lithium-sulfur full cell with a low negative-to-positive capacity ratio of 2.4, while exhibiting stable cyclability with an initial discharge capacity of 550 mAh g-1 and 60% capacity retention after 200 cycles.

Synthesis and evaluation of Fmoc-amino esters and amides bearing a substrate like quaternary ammonium group as selective butyrylcholinesterase inhibitors

The depletion of the neurotransmitter acetylcholine has been suggested to contribute to the reduced cognitive function observed in individuals suffering from neurodegenerative diseases such as Alzheimer’s Disease (AD). For the two major cholinesterases, butyrylcholinesterase (BChE) and acetylcholinesterase (AChE), increased BChE activity observed in individuals with AD has been suggested to deplete acetylcholine levels. To reduce acetylcholine degradation and help restore the pool of the neurotransmitter, specific and potent BChE inhibitors are sought. Our previous findings have identified 9-fluorenylmethoxycarbonyl (Fmoc) amino acid-based inhibitors as effective BChE inhibitors. The amino acid-based compounds offered the opportunity to survey a range of structural features to enhance interactions with the enzyme active site. As enzymes interact with features of their substrates, incorporation of substrate-like features was predicted to lead to better inhibitors. Specifically, incorporation of a trimethylammonium moiety to mimic the cationic group of acetylcholine may lead to increased potency and selectivity. To test this model, a series of inhibitors bearing a cationic trimethylammonium group were synthesized, purified, and characterized. While the Fmoc-ester derivatives inhibited the enzyme, additional experiments showed the compounds acted as substrates and were enzymatically hydrolyzed. Inhibition studies with the Fmoc-amide derivatives showed that the compounds do not act as substrates and selectively inhibit BChE with IC50 values in the 0.06–10.0 µM range. Computational docking studies suggest that the inhibitors can interact with cholinyl binding site and peripheral site. Overall, the results suggest that introducing substrate-like characteristics within the Fmoc-amino acid-based background increases their potency. The versatile and ready access to amino acid-based compounds offers an attractive system to further our understanding of the relative importance of protein-small molecule interactions while guiding the development of better inhibitors.

Green Synthesis and the Evaluation of a Functional Amphiphilic Block Copolymer as a Micellar Curcumin Delivery System.

Polymer micelles represent one of the most attractive drug delivery systems due to their design flexibility based on a variety of macromolecular synthetic methods. The environmentally safe chemistry in which the use or generation of hazardous materials is minimized has an increasing impact on polymer-based drug delivery nanosystems. In this work, a solvent-free green synthetic procedure was applied for the preparation of an amphiphilic diblock copolymer consisting of biodegradable hydrophobic poly(acetylene-functional carbonate) and biocompatible hydrophilic polyethylene glycol (PEG) blocks. The cyclic functional carbonate monomer 5-methyl-5-propargyloxycarbonyl-1,3-dioxane-2-one (MPC) was polymerized in bulk using methoxy PEG-5K as a macroinitiator by applying the metal-free organocatalyzed controlled ring-opening polymerization at a relatively low temperature of 60 °C. The functional amphiphilic block copolymer self-associated in aqueous media into stable micelles with an average diameter of 44 nm. The copolymer micelles were physico-chemically characterized and loaded with the plant-derived anticancer drug curcumin. Preliminary in vitro evaluations indicate that the functional copolymer micelles are non-toxic and promising candidates for further investigation as nanocarriers for biomedical applications.

Incorporation of Heteroatomic Fe Activates Rapid Catalytic Behaviors of Co3O4 Hollow Nanoplates Toward Advanced Lithium–Sulfur Batteries

AbstractLithium–sulfur (Li–S) battery is a highly attractive energy storage system due to its high capacity and great affordability. However, the parasitic shuttle effect and sluggish redox kinetics are perplexing the fulfillment of efficient battery electrochemistry. To tackle these challenges, herein, a hierarchical and hollow nanoplate assembled by Fe‐doped Co3O4 nanosheets (Fe–Co3O4 HHNPs) is meticulously designed as an advanced sulfur nanoreactor. The interlaced nanosheets establish a robust and porous network for fast charge transfer and efficient active site exposure. More importantly, the heteroatomic Fe incorporation tailors the electronic structure via local structure distortion and electron redistribution, contributing to massive active sites that lower the energy barrier for sulfur conversions. The resulting sulfur adsorption and catalyzation endow the Li–S cells with minimum capacity decay of 0.08% per cycle over 500 cycles and decent rate performance up to 5 C. Moreover, a high areal capacity of 9.0 mAh cm−2 after 55 cycles is also achievable under raised sulfur loading of 11 mg cm−2 and limited electrolyte (E/S = 3.9 µL mg−1). This work provides an elaborate and instructive paradigm for designing catalytic nanoreactors toward superior Li–S electrochemistry.

FoxO and rotund form a binding complex governing wing polyphenism in planthoppers

Wing polyphenism is found in a variety of insects and offers an attractive model system for studying the evolutionary significance of dispersal. The Forkhead box O (FoxO) transcription factor (TF) acts as a wing-morph switch that directs wing buds developing into long-winged (LW) or short-winged morphs in wing-dimorphic planthoppers, yet the regulatory mechanism of the FoxO module remains elusive. Here, we identified the zinc finger TF rotund as a potential wing-morph regulator via transcriptomic analysis and phenotypic screening in the brown plathopper, Nilaparvata lugens. RNA interference-mediated knockdown of rotund antagonized the LW development derived from in the context of FoxO depletion or the activation of the insulin/insulin-like growth factor signaling cascade, reversing long wings into intermediate wings. Invitro binding assays indicated that rotund physically binds to FoxO to form the FoxO combinatorial code. These findings broaden our understanding of the complexity of transcriptional regulation governing wing polyphenism in insects.

Long-term Outcome of Sound Localization with Baha® Attract System.

Spatial hearing is a critical feature in daily life. However, there is quite a range in hearing loss patients regarding the effect of bone conduction device on localization performance. To analyze the localization performance in patients with bilateral conductive or mixed hearing loss fitted with one Baha® Attract system. This prospective study included 12 patients who had followed up for more than one year. The parameters analyzed included (1) audiological results: sound field threshold, speech discrimination scores (SDSs), and sound localization test, and (2) functional results: scores for the Speech, Spatial and Qualities of Hearing Scale (SSQ) and the Chinese translation of the Spatial Hearing Questionnaire (C-SHQ). The audiological assessments showed a reduction of 28.5 dB in the mean sound field thresholds and improvements of 61.7% in the SDSs for disyllabic words. The root mean square error improved slightly with the Baha® Attract system. Patients showed promising results in the functional questionnaire assessments, with significant improvements in the SSQ and C-SHQ scores. Although most patients were not able to localize sound accurately after surgery, the change in the scores of the SSQ and C-SHQ indicated that the Baha® Attract system could improve spatial hearing.

Porphyrins-mediated interfacial charge modulation to enhance aggregation-induced electrochemiluminescence of iridium complex for ultrasensitive bioassay

Iridium (III) complexes have attracted much attention as electrochemiluminescence (ECL) luminophores, but their inferior ECL efficiency (ΦECL) in the aqueous solutions has impeded further applications. Herein, meso-tetra (4-carboxyphenyl) porphine (TCPP) was developed as interfacial charge mediator to dramatically enhance aggregation-induced electrochemiluminescence (AIECL) of tris (2-phenylpyridine) iridium(Ⅲ) (Ir(ppy)3), thus improving its ΦECL. As an interfacial charge mediator, TCPP can efficiently accelerate the electrooxidation of Ir(ppy)3 through higher hole transport kinetics. Meanwhile, it is found that its rigid structure can suppress the motions of Ir(ppy)3 to elevate radiative transition efficiency in emission process. Thus, a significantly enhanced AIECL was achieved for aggregation-induced emission luminogens (AIEgens) Ir(ppy)3 @TCPP. Compared to monomer Ir(ppy)3, Ir(ppy)3 @TCPP increased ECL efficiency by 18 times. Ir(ppy)3 @TCPP served as AIEgens to construct ECL biosensor for detecting miRNA-126. Strand-displacement amplification (SDA) coupled with rolling-circle amplification (RCA) for improving the conversion efficiency of target miRNA-126. The integration of excellent AIECL characteristics of Ir(ppy)3 @TCPP and outstanding amplification efficiency of SDA-RCA endowed sensing system with high sensitivity. The limit of detection (LOD) was as low as 17 aM. This work creatively exploited interfacial charge modulation as an effective way to enhance AIECL efficiency. The prepared Ir(ppy)3 @TCPP provided much attractive ECL system for bioanalysis.

In Operando Photoswitching of Cu Oxidation States in Cu-Based Plasmonic Heterogeneous Photocatalysis for Efficient H2 Evolution.

Metal nanoparticles (NP) supported on TiO2 are known to be efficient photocatalysts for solar-to-chemical energy conversion. While TiO2 decorated with copper NPs has the potential to become an attractive system, the poor oxidative stability of Cu severely limits its applicability. In this work, we demonstrate that, when Cu NPs supported on TiO2 nanobelts (NBs) are engaged in the photocatalytic generation of H2 from water under light illumination, Cu is not only oxidized in CuO but also dissolved under the form of Cu+/Cu2+ ions, leading to a continuous reconstruction of nanoparticles via Ostwald ripening. By nanoencapsulating the CuOx (Cu/CuO/Cu2O) NPs by a few layers of carbon supported on TiO2 (TC@C), Ostwald ripening can be suppressed. Simultaneously, the resulting CuOx@C NPs are photoreduced under light illumination to generate Cu@C NPs. This photoswitching strategy allows the preparation of a Cu plasmonic photocatalyst with enhanced activity for H2 production. Remarkably, the photocatalyst is even active when illuminated with visible light, indicating a clear plasmonic enhancement of photocatalytic activity from the surface plasmonic resonance (SPR) effect of Cu NPs. Three-dimensional electromagnetic wave-frequency domain (3D-EWFD) simulations were conducted to confirm the SPR enhancement. This advance bodes for the development of scalable multifunctional Cu-based plasmonic photocatalysts for solar energy transfer.

Incorporation of Resveratrol in Polymeric Nanogel for Improvement of Its Protective Effects on Cellular and Microsomal Oxidative Stress Models.

Nanogels are attractive drug delivery systems that provide high loading capacity for drug molecules, improve their stability, and increase cellular uptake. Natural antioxidants, especially polyphenols such as resveratrol, are distinguished by low aqueous solubility, which hinders therapeutic activity. Thus, in the present study, resveratrol was incorporated into nanogel particles, aiming to improve its protective effects in vitro. The nanogel was prepared from natural substances via esterification of citric acid and pentane-1,2,5-triol. High encapsulation efficiency (94.5%) was achieved by applying the solvent evaporation method. Dynamic light scattering, atomic force microscopy, and transmission electron microscopy revealed that the resveratrol-loaded nanogel particles were spherical in shape with nanoscopic dimensions (220 nm). In vitro release tests showed that a complete release of resveratrol was achieved for 24 h, whereas at the same time the non-encapsulated drug was poorly dissolved. The protective effect of the encapsulated resveratrol against oxidative stress in fibroblast and neuroblastoma cells was significantly stronger compared to the non-encapsulated drug. Similarly, the protection in a model of iron/ascorbic acid-induced lipid peroxidation on rat liver and brain microsomes was higher with the encapsulated resveratrol. In conclusion, embedding resveratrol in this newly developed nanogel improved its biopharmaceutical properties and protective effects in oxidative stress models.

Interfacial origin of dielectric constant enhancement in high-temperature polymer dilute nanocomposites

The origin of dielectric constant enhancement in high-temperature (high glass transition temperature Tg) polymer dilute nanocomposites is investigated via Infrared (IR) Spectroscopy applied through Atomic Force Microscope (AFM) and density functional theory (DFT) calculations. The dielectric constant can be greatly enhanced by trace nanofiller loadings (&amp;lt;0.5 vol. %) in a broad class of high-temperature polymers without affecting or even with a positive influence on breakdown strength and dielectric loss. This avenue provides attractive polymer systems for high-performance polymer-based capacitive energy storage in a wide temperature range. In the dilute nanocomposites, the interface regions between the polymers and trace nanofillers are the key to the observed dielectric constant enhancement. This Letter employs AFM-IR to study chain packing in the interface regions of polyetherimide (PEI) dilute nanocomposites. The experimental results and DFT calculations indicate that flexible linkages, i.e., ether groups in PEI, play a crucial role in inducing heterogeneous morphologies in the interface regions. These results are confirmed by studies of PI(PDMA/ODA) and other dilute polymer nanocomposites in the literature as well as by lack of dielectric constant enhancement in PI(Matrimid® 5218) that does not contain flexible linkages.