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The hierarchical porous structure has garnered considerable attention as a multiscale engineering strategy to bring unforeseen synergistic effects in a vast variety of functional materials. Here, we demonstrate a "microporous covalent organic framework (COF) net on mesoporous carbon nanotube (CNT) net" hybrid architecture as a new class of molecularly designed, hierarchical porous chemical trap for lithium polysulfides (Li2Sx) in Li-S batteries. As a proof of concept for the hybrid architecture, self-standing COF-net on CNT-net interlayers (called "NN interlayers") are fabricated through CNT-templated in situ COF synthesis and then inserted between sulfur cathodes and separators. Two COFs with different micropore sizes (COF-1 (0.7 nm) and COF-5 (2.7 nm)) are chosen as model systems. The effects of the pore size and (boron-mediated) chemical affinity of microporous COF nets on Li2Sx adsorption phenomena are theoretically investigated through density functional theory calculations. Benefiting from the chemical/structural uniqueness, the NN interlayers effectively capture Li2Sx without impairing their ion/electron conduction. Notably, the COF-1 NN interlayer, driven by the well-designed microporous structure, allows for the selective deposition/dissolution (i.e., facile solid-liquid conversion) of electrically inert Li2S. As a consequence, the COF-1 NN interlayer provides a significant improvement in the electrochemical performance of Li-S cells (capacity retention after 300 cycles (at charge/discharge rate = 2.0 C/2.0 C) = 84% versus 15% for a control cell with no interlayer) that lies far beyond those accessible with conventional Li-S technologies.
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Forthcoming flexible/wearable electronic devices with shape diversity and mobile usability garner a great deal of attention as an innovative technology to bring unprecedented changes in our daily lives. From the power source point of view, conventional rechargeable batteries (one representative example is a lithium-ion battery) with fixed shapes and sizes have intrinsic limitations in fulfilling design/performance requirements for the flexible/wearable electronics. Here, as a facile and efficient strategy to address this formidable challenge, we demonstrate a new class of printable solid-state batteries (referred to as "PRISS batteries"). Through simple stencil printing process (followed by ultraviolet (UV) cross-linking), solid-state composite electrolyte (SCE) layer and SCE matrix-embedded electrodes are consecutively printed on arbitrary objects of complex geometries, eventually leading to fully integrated, multilayer-structured PRISS batteries with various form factors far beyond those achievable by conventional battery technologies. Tuning rheological properties of SCE paste and electrode slurry toward thixotropic fluid characteristics, along with well-tailored core elements including UV-cured triacrylate polymer and high boiling point electrolyte, is a key-enabling technology for the realization of PRISS batteries. This process/material uniqueness allows us to remove extra processing steps (related to solvent drying and liquid-electrolyte injection) and also conventional microporous separator membranes, thereupon enabling the seamless integration of shape-conformable PRISS batteries (including letters-shaped ones) into complex-shaped objects. Electrochemical behavior of PRISS batteries is elucidated via an in-depth analysis of cell impedance, which provides a theoretical basis to enable sustainable improvement of cell performance. We envision that PRISS batteries hold great promise as a reliable and scalable platform technology to open a new concept of cell architecture and fabrication route toward flexible power sources with exceptional shape conformability and aesthetic versatility.
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Bulk-type all-solid-state lithium batteries (ASLBs) are considered a promising candidate to outperform the conventional lithium-ion batteries. Unfortunately, the current technology level of ASLBs is in a stage of infancy in terms of cell-based (not electrode-material-based) energy densities and scalable fabrication. Here, we report on the first ever bendable and thin sulfide solid electrolyte films reinforced with a mechanically compliant poly(paraphenylene terephthalamide) nonwoven (NW) scaffold, which enables the fabrication of free-standing and stackable ASLBs with high energy density and high rate capabilities. The ASLB, using a thin (â¼70 µm) NW-reinforced SE film, exhibits a 3-fold increase of the cell-energy-density compared to that of a conventional cell without the NW scaffold.
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Small gold nanoparticles (AuNPs) that possess interfacial methyl-2-(diphenylphosphino)benzoate moieties have been successfully synthesized (Staudinger-AuNPs) and characterized by multi-nuclear MR spectroscopy, transmission electron microscopy (TEM), UV-Vis spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS). In particular, XPS was remarkably sensitive for characterization of the novel nanomaterial, and in furnishing proof of its interfacial reactivity. These Staudinger-AuNPs were found to be stable to the oxidation of the phosphine center. The reaction with benzyl azide in a Staudinger-Bertozzi ligation, as a model system, was investigated using (31)P NMR spectroscopy. This demonstrated that the interfacial reaction was clean and quantitative. To showcase the potential utility of these Staudinger-AuNPs in bioorganic chemistry, a AuNP bioconjugate was prepared by reacting the Staudinger-AuNPs with a novel azide-labeled CRGDK peptide. The CRGDK peptide could be covalently attached to the AuNP efficiently, chemoselectively, and with a high loading.
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Benzoatos/química , Ouro/química , Nanopartículas/química , Fosfinas/química , Azidas/química , Metilação , Nanopartículas/ultraestrutura , Oligopeptídeos/química , Tamanho da Partícula , Espectroscopia Fotoeletrônica , TermogravimetriaRESUMO
The rapidly approaching smart/wearable energy era necessitates advanced rechargeable power sources with reliable electrochemical properties and versatile form factors. Here, as a unique and promising energy storage system to address this issue, we demonstrate a new class of heterolayered, one-dimensional (1D) nanobuilding block mat (h-nanomat) battery based on unitized separator/electrode assembly (SEA) architecture. The unitized SEAs consist of wood cellulose nanofibril (CNF) separator membranes and metallic current collector-/polymeric binder-free electrodes comprising solely single-walled carbon nanotube (SWNT)-netted electrode active materials (LiFePO4 (cathode) and Li4Ti5O12 (anode) powders are chosen as model systems to explore the proof of concept for h-nanomat batteries). The nanoporous CNF separator plays a critical role in securing the tightly interlocked electrode-separator interface. The SWNTs in the SEAs exhibit multifunctional roles as electron conductive additives, binders, current collectors and also non-Faradaic active materials. This structural/physicochemical uniqueness of the SEAs allows significant improvements in the mass loading of electrode active materials, electron transport pathways, electrolyte accessibility and misalignment-proof of separator/electrode interface. As a result, the h-nanomat batteries, which are easily fabricated by stacking anode SEA and cathode SEA, provide unprecedented advances in the electrochemical performance, shape flexibility and safety tolerance far beyond those achievable with conventional battery technologies. We anticipate that the h-nanomat batteries will open 1D nanobuilding block-driven new architectural design/opportunity for development of next-generation energy storage systems.
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This study investigates the relationship between political orientation, government change, and public satisfaction with food policies in the Republic of Korea. Utilizing data from the Consumer Behavior Survey for Foods (CBSF) conducted by the Korea Rural Economic Institute from 2020 to 2021, we employ fixed effects models to examine the impact of political orientation, the presence of a conservative government, and their interactions on satisfaction across various dimensions of food policy. We also analyze the change in satisfaction levels from 2020 to 2021 based on shifts in political orientation. The results reveal complex dynamics between political alignment, government performance, and public perceptions. While conservatives and liberals exhibit higher satisfaction with labeling policies, they show lower satisfaction with safety and redress policies. The presence of a conservative government is associated with higher satisfaction in specific policy areas but lower overall satisfaction. Changes in political orientation significantly influence policy satisfaction, with shifts away from conservatism and towards liberalism leading to decreased satisfaction. The findings highlight the importance of understanding the nuanced preferences of different political groups and the need for responsive and transparent food policy frameworks. This study advances the theoretical understanding of the political economy of policy satisfaction and provides novel policy implications for effective governance.
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Coupling thin Li metal anodes with high-capacity/high-voltage cathodes such as LiNi0.8Co0.1Mn0.1O2 (NCM811) is a promising way to increase lithium battery energy density. Yet, the realization of high-performance full cells remains a formidable challenge. Here, we demonstrate a new class of highly coordinated, nonflammable carbonate electrolytes based on lithium bis(fluorosulfonyl)imide (LiFSI) in propylene carbonate/fluoroethylene carbonate mixtures. Utilizing an optimal salt concentration (4 M LiFSI) of the electrolyte results in a unique coordination structure of Li+-FSI--solvent cluster, which is critical for enabling the formation of stable interfaces on both the thin Li metal anode and high-voltage NCM811 cathode. Under highly demanding cell configuration and operating conditions (Li metal anode = 35 µm, areal capacity/charge voltage of NCM811 cathode = 4.8 mAh cm-2/4.6 V, and anode excess capacity [relative to the cathode] = 0.83), the Li metal-based full cell provides exceptional electrochemical performance (energy densities = 679 Wh kgcell-1/1,024 Wh Lcell-1) coupled with nonflammability.
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The detailed synthetic protocols for the preparation of phosphoramidite reagents compatible with standard, automated oligonucleotide synthesis for the 2'-deoxy- and ribo-6-phenylpyrrolocyitidine are reported. Each protocol starts with the parent nucleoside and prepares the 5'-O-dimethoxytrityl-N4 -benzoyl-5-iodocytosine derivative for the nucleobase modification chemistry. The key step is the direct formation of 6-phenylpyrrolocytosine aglycon via a sequential, one-pot Pd-catalyzed Sonogashira-type cross- coupling followed by a 5-endo-dig cyclization. Subsequent standard transformations provide the deoxy- and 2'-O-tert-butyldimethysilyl protected ribo- nucleoside phosphoramidite reagents. © 2019 by John Wiley & Sons, Inc.
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Citidina/análogos & derivados , Corantes Fluorescentes/química , Nucleosídeos/química , Pirróis/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Citidina/química , Compostos Organofosforados/química , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
BACKGROUND: Neuroblastoma, a frequently occurring solid tumour in children, remains a therapeutic challenge as existing imaging tools are inadequate for proper and accurate diagnosis, resulting in treatment failures. Nanoparticles have recently been introduced to the field of cancer research and promise remarkable improvements in diagnostics, targeting and drug delivery. Among these nanoparticles, quantum dots (QDs) are highly appealing due to their manipulatable surfaces, yielding multifunctional QDs applicable in different biological models. The biocompatibility of these QDs, however, remains questionable. RESULTS: We show here that QD surface modifications with N-acetylcysteine (NAC) alter QD physical and biological properties. In human neuroblastoma (SH-SY5Y) cells, NAC modified QDs were internalized to a lesser extent and were less cytotoxic than unmodified QDs. Cytotoxicity was correlated with Fas upregulation on the surface of treated cells. Alongside the increased expression of Fas, QD treated cells had increased membrane lipid peroxidation, as measured by the fluorescent BODIPY-C11 dye. Moreover, peroxidized lipids were detected at the mitochondrial level, contributing to the impairment of mitochondrial functions as shown by the MTT reduction assay and imaged with confocal microscopy using the fluorescent JC-1 dye. CONCLUSION: QD core and surface compositions, as well as QD stability, all influence nanoparticle internalization and the consequent cytotoxicity. Cadmium telluride QD-induced toxicity involves the upregulation of the Fas receptor and lipid peroxidation, leading to impaired neuroblastoma cell functions. Further improvements of nanoparticles and our understanding of the underlying mechanisms of QD-toxicity are critical for the development of new nanotherapeutics or diagnostics in nano-oncology.
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We examine the impact of current and future climate on crop mixes over space in the US. We find using historical data that temperature and precipitation are among the causal factors for shits in crop production location and mixes, with some crops being more sensitive than others. In particular, we find that when temperature rises, cotton, rice, sorghum and winter wheat are more likely to be chosen. We also find that barley, sorghum, winter wheat, spring wheat and hay are more likely to be chosen as regions become drier, and corn, cotton, rice and soybeans are more likely to be selected in wetter regions. Additionally, we assess how much of the observed crop mix shifts between 1970 and 2010 were contributed to by climate change. There we find climate explains about 7-50% of the shift in latitude, 20-36% in longitude and 4-28% of that in elevation. Finally, we estimate climate change impacts on future crop mix under CMIP5 scenarios. There we find shifts in US production regions for almost all major crops with the movement north and east. The estimates describe how the farmers respond to altering climate and can be used for planning future crop allocations.
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Quantum dots (QDs) are luminescent nanoparticles with unique optical properties that have been exploited for single-cell and whole-animal imaging. When coated with proteins or biocompatible polymers, QDs are not deleterious to cells and organisms. However, when QDs are retained in cells or accumulated in the body for a long period of time, their coatings may be degraded, yielding "naked" QDs. Here, we show that "naked" QDs induce damage to the plasma membrane, mitochondrion, and nucleus, leading to cell death. Reactive oxygen species (ROS) are important players in mediating QD-induced cellular damage. QD-induced cytotoxicity can be reduced or even eliminated without covalent binding of protective agents to the QD surface. Results from these studies suggest the critical role of several subcellular compartments in QD-induced cytotoxicity and point toward multiple molecular targets in nonclassical apoptosis.
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Compostos de Cádmio/química , Compostos de Cádmio/farmacologia , Organelas/efeitos dos fármacos , Organelas/patologia , Pontos Quânticos , Espécies Reativas de Oxigênio/metabolismo , Telúrio/química , Telúrio/farmacologia , Acetilcisteína/farmacologia , Caspases/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Citocromos c/metabolismo , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Organelas/metabolismoRESUMO
Silica solid substrates such as fused silica, silicon wafers with a natural oxide layer, and glass were treated with aziridine to produce reactive primary amine groups on the top surface. We found that the hydroxyl group on the substrate was able to initiate the ring-opening polymerization of aziridine, resulting in highly branched poly(ethyleneimine) on the surface. In dichloromethane, the thickness of the organic film reached 25 A in 20 h and the absolute density of the primary amine group on the surface was 23 amines/nm(2). Atomic force microscopy shows an embossed morphology after the polymerization in dichloromethane, while use of toluene gives a rather smooth surface. The resulting organic layer shows high thermal and pH stability.
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The first synthesis of a triphenylmethine (TM) library of compounds and screening of their Surface Enhanced Raman Scattering (SERS) capability was carried out to identify novel Raman reporters with high sensitivity. We identified three novel SERS reporters (B2, B7, and C7) with higher signal intensity than that of commonly used crystal violet (CV). These reporters may find potential applications in developing sensitive SERS based biosensors.
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Técnicas Biossensoriais/métodos , Técnicas de Química Combinatória/métodos , Microscopia de Varredura por Sonda/métodos , Compostos de Terfenil/síntese química , Estrutura Molecular , Análise Espectral Raman , Propriedades de Superfície , Compostos de Terfenil/químicaRESUMO
Several studies suggested that the cytotoxic effects of quantum dots (QDs) may be mediated by cadmium ions (Cd2+) released from the QDs cores. The objective of this work was to assess the intracellular Cd2+ concentration in human breast cancer MCF-7 cells treated with cadmium telluride (CdTe) and core/shell cadmium selenide/zinc sulfide (CdSe/ZnS) nanoparticles capped with mercaptopropionic acid (MPA), cysteamine (Cys), or N-acetylcysteine (NAC) conjugated to cysteamine. The Cd2+ concentration determined by a Cd2+-specific cellular assay was below the assay detection limit (<5 nM) in cells treated with CdSe/ZnS QDs, while in cells incubated with CdTe QDs, it ranged from approximately 30 to 150 nM, depending on the capping molecule. A cell viability assay revealed that CdSe/ZnS QDs were nontoxic, whereas the CdTe QDs were cytotoxic. However, for the various CdTe QD samples, there was no dose-dependent correlation between cell viability and intracellular [Cd2+], implying that their cytotoxicity cannot be attributed solely to the toxic effect of free Cd2+. Confocal laser scanning microscopy of CdTe QDs-treated cells imaged with organelle-specific dyes revealed significant lysosomal damage attributable to the presence of Cd2+ and of reactive oxygen species (ROS), which can be formed via Cd2+-specific cellular pathways and/or via CdTe-triggered photoxidative processes involving singlet oxygen or electron transfer from excited QDs to oxygen. In summary, CdTe QDs induce cell death via mechanisms involving both Cd2+ and ROS accompanied by lysosomal enlargement and intracellular redistribution.
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Compostos de Cádmio/química , Pontos Quânticos , Telúrio/química , Cádmio/química , Cádmio/farmacologia , Compostos de Cádmio/toxicidade , Cátions Bivalentes/química , Sobrevivência Celular/efeitos dos fármacos , Humanos , Nanopartículas/química , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Telúrio/toxicidade , Fatores de TempoRESUMO
Anti-glycation activity of our anti-oxidant quinone library was measured and several 2,3-dimethoxy-5-methyl-1,4-benzoquinones and 2-methyl-1,4-naphthoquinones were identified as novel inhibitors of glycation, of which 2,3-dimethoxy-5-methyl-1,4-benzoquinones 13b is the most potent glycation inhibitor with around 50 microM of the IC(50) value.
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Benzoquinonas/síntese química , Glicosilação/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Naftoquinonas/síntese química , Animais , Antioxidantes/síntese química , Antioxidantes/farmacologia , Benzoquinonas/farmacologia , Produtos Finais de Glicação Avançada/antagonistas & inibidores , Humanos , Concentração Inibidora 50 , Naftoquinonas/farmacologia , Relação Estrutura-AtividadeRESUMO
Novel hydroxypyrazoline derivatives of tetracycline and minocycline have been synthesized through the reaction of these tetracyclines with hydrazine. The formation of a new chiral center at C12 is stereospecific to give 12S-12-hydroxy-1,12-pyrazolinotetracycline. A reaction mechanism for the formation of these novel tetracycline derivatives has been proposed. Hydroxypyrazolinotetracyclines exhibit no binding to Mg2+ and Zn2+, features that are required for antibiotic activity and matrix metalloproteinase (MMP) inhibitions, respectively. The modification toward their hydroxypyrazolino derivatives significantly improved the antioxidant activities of tetracycline and minocycline, as shown by three commonly used assays (DPPH, ABTS+, and superoxide scavenging). 12S-Hydroxy-1,12-pyrazolinominocycline is a promising tetracycline-based antioxidant devoid of antibiotic properties and MMP inhibitory activity, which could be beneficial in the treatment of complications related to oxidative stress.