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In this work, in order to intensify the oxidation of starch with sodium hypochlorite, mechanical activation of starch suspension in a rotor-stator device (RSD) was used for the first time. Activation of starch suspension (concentrations of 10, 20, 30 and 40%) before oxidation was carried out for 10, 20, and 30 s in two ways: either before the introduction of the oxidizing agent (A-OS) or after its introduction (AOS). The activation of starch in RSD for 10–30 s increased the rate of oxidant consumption during subsequent oxidation. The oxidized starches were analyzed by scanning electron microscopy (SEM), X-ray diffraction, and FTIR spectroscopy. Mechanical activation caused erosion of starch granules, increased porosity and specific surface areas.The mechanical activation of the starch increased the content of carbonyl groups in the range 46–61% and that of carboxyl groups in the range 60–100%, compared with the oxidation without activation (OS). In the case of (AOS), a higher yield of carbonyl and carboxyl groups was achieved compared to (A-OS). It was found that the effective viscosity and consistency coefficient of the starch hydrogels monotonically decrease as the duration of preactivation of the starch suspensions increased. Mechanical activation in RSD can be used to improve the oxidizing degree of oxidized starch or to reduce process time on a large scale.

Neurodegenerative disorders, including Tauopathies that involve tau protein, base their pathological mechanism on forming proteinaceous aggregates, which has a deleterious effect on cells triggering an inflammatory response. Moreover, tau inhibitors can exert their mechanism of action through noncovalent and covalent interactions. Thus, Michael’s addition appears as a feasible type of interaction involving an α, β unsaturated carbonyl moiety to avoid pathological confirmation and further cytotoxicity. Moreover, we isolated three compounds from Antarctic lichens Cladonia cariosa and Himantormia lugubris: protolichesterinic acid (1), fumarprotocetraric acid (2), and lichesterinic acid (3). The maleimide cysteine labeling assay showed that compounds 1, 2, and 3 inhibit at 50 µM, but compounds 2 and 3 are statistically significant. Based on its inhibition capacity, we decided to test compound 2 further. Thus, our results suggest that compound 2 remodel soluble oligomers and diminish β sheet content, as demonstrated through ThT experiments. Hence, we added externally treated oligomers with compound 2 to demonstrate that they are harmless in cell culture. First, the morphology of cells in the presence of aggregates does not suffer evident changes compared to the control. Additionally, the externally added aggregates do not provoke a substantial LDH release compared to the control, indicating that treated oligomers do not provoke membrane damage in cell culture compared with aggregates alone. Thus, in the present work, we demonstrated that Michael’s acceptors found in lichens could serve as a scaffold to explore different mechanisms of action to turn tau aggregates into harmless species.

Oil oxidation in an oil-rich system was used to investigate the effect on acrylamide formation. Three kinds of common oil, soybean oil, olive oil, and palm oil, were preheated at different temperatures (120, 150, 180, and 210°C) for different times (0, 5, 10, 15, and 20 h). The oil-rich model systems were composed of pretreated oil and asparagine. Acid value, peroxide value, p-anisidine value, and carbonyl group value were used to monitor the degree of lipid oxidation in the model system. Our results showed that the content of acrylamide increased with oil preheat time and temperature. The highest yield of acrylamide in soybean oil was 0.26 ± 0.012 μg/mL after 20 h of incubation at 210°C. Oil oxidation indices correlated significantly with the content of acrylamide. The peroxide value could provide more information for references about acrylamide formation in soybean and olive oil systems.

Carbon nanotubes (CNTs) were considered a promising activator for persulfates due to their high electrical conductivity, large specific surface area and low toxicity. The functional groups and surface defects of CNTs could significantly affect their activation performance. In this study, CNTs with high C=O ratio and defect density (CNT-O-H) were prepared through a facile treatment of raw CNTs with HNO3 oxidation followed by calcination at 800 °C under an argon atmosphere. X-ray photoelectron spectroscopy (XPS) and Raman results showed that the C=O proportion and defect degree (ID/IG) rose to 75% and 1.53, respectively. The obtained CNT-O-H possessed a superior performance towards peroxydisulfate (PDS) activation, and the degradation efficiency of tetracycline (TC) in the CNT-O-H/PDS system was increased to 75.2% from 56.2% of the raw CNTs/PDS system within 40 min. Moreover, the activity of CNT-O-H after use could be easily recovered with re-calcination. In addition, the CNT-O-H/PDS system exhibited high adaptabilities towards wide solution pH (2–10), common coexisting substances and diverse organic pollutants. Singlet oxygen (1O2) was confirmed to be the dominant reactive oxygen species (ROS) generated in the CNT-O-H/PDS system. It was inferred that surface C=O groups and defects of CNTs were the key site to activate PDS for TC degradation.

Nanozymes with superoxide dismutase (SOD)-like activity have attracted increasing interest due to their ability to scavenge superoxide anion, the origin of most reactive oxygen species in vivo. However, SOD nanozymes reported thus far have yet to approach the activity of natural enzymes. Here, we report a carbon dot (C-dot) SOD nanozyme with a catalytic activity of over 10,000 U/mg, comparable to that of natural enzymes. Through selected chemical modifications and theoretical calculations, we show that the SOD-like activity of C-dots relies on the hydroxyl and carboxyl groups for binding superoxide anions and the carbonyl groups conjugated with the π-system for electron transfer. Moreover, C-dot SOD nanozymes exhibit intrinsic targeting ability to oxidation-damaged cells and effectively protect neuron cells in the ischemic stroke male mice model. Together, our study sheds light on the structure-activity relationship of C-dot SOD nanozymes, and demonstrates their potential for treating of oxidation stress related diseases. Superoxide dismutase (SOD) nanozymes show mitigating effect on oxidative stress-related diseases, but are limited by their modest activity. Here, the authors report a carbon dot SOD nanozyme with catalytic activity matching natural enzymes and unveil its catalytic mechanism.

Self-repairable materials strive to emulate curable and resilient biological tissue; however, their performance is currently insufficient for commercialization purposes because mending and toughening are mutually exclusive. Herein, we report a carbonate-type thermoplastic polyurethane elastomer that self-heals at 35 °C and exhibits a tensile strength of 43 MPa; this elastomer is as strong as the soles used in footwear. Distinctively, it has abundant carbonyl groups in soft-segments and is fully amorphous with negligible phase separation due to poor hard-segment stacking. It operates in dual mechano-responsive mode through a reversible disorder-to-order transition of its hydrogen-bonding array; it heals when static and toughens when dynamic. In static mode, non-crystalline hard segments promote the dynamic exchange of disordered carbonyl hydrogen-bonds for self-healing. The amorphous phase forms stiff crystals when stretched through a transition that orders inter-chain hydrogen bonding. The phase and strain fully return to the pre-stressed state after release to repeat the healing process. Self-healing materials strive to emulate curable and resilient biological tissue but their performance is often insufficient for commercial applications because self-healing and toughening are mutually exclusive properties. Here, the authors report a tough and strong carbonate-type thermoplastic polyurethane elastomer that self-heals at ambient temperature.

The continuous increase in manufacturing coupled with the difficulty of recycling of plastic products has generated huge amounts of waste plastics. Most of the existing chemical recycling and upcycling methods suffer from harsh conditions and poor product selectivity. Here we demonstrate a photocatalytic method to oxidize polystyrene to aromatic oxygenates under visible light irradiation using heterogeneous graphitic carbon nitride catalysts. Benzoic acid, acetophenone, and benzaldehyde are the dominant products in the liquid phase when the conversion of polystyrene reaches >90% at 150 °C. For the transformation of 0.5 g polystyrene plastic waste, 0.36 g of the aromatic oxygenates is obtained. The reaction mechanism is also investigated with various characterization methods and procedes via polystyrene activation to form hydroxyl and carbonyl groups over its backbone via C–H bond oxidation which is followed by oxidative bond breakage via C–C activation and further oxidation processes to aromatic oxygenates. There is a real need to create materials capable of plastic recycling and upcycling. Here, the authors report a heterogeneous carbon nitride photocatalyst which efficiently converts polystyrene plastics into aromatic oxygenates, such as benzoic acid.

The development of azide migration reactions is a formidable challenge due to potential competition from side processes driven by the release of molecular nitrogen. Here, we show a novel neighbouring carbonyl group-assisted sequential 1,2-azide and 1,4-oxygen migration reaction of α-vinyl azides for the efficient preparation of a range of α-azido ketones. This represents the first transformation of α-vinyl azides into α-azido ketones. Notable features of this method are its high efficiency, broad substrate scope, excellent functional group compatibility, and high yields. The computational studies gave a key insights into the regioselective 1,2-azide and 1,4-oxygen migrations assisted by the neighbouring carbonyl group. Further conversions into a variety of nitrogen-containing compounds demonstrated the synthetic utility of the α-azido ketone products. Preliminary mechanistic studies disclosed a novel reaction mechanism involving neighbouring carbonyl group-assisted sequential 1,2-azide and 1,4-oxygen migrations.

Circumventing the conventional two-electron oxygen reduction pathway remains a great problem in enhancing the efficiency of H 2 O 2 photosynthesis. A promising approach to achieve outstanding photocatalytic activity involves the utilization of redox intermediates. Here, we engineer a polyimide aerogel photocatalyst with photoreductive carbonyl groups for non-sacrificial H 2 O 2 production. Under photoexcitation, carbonyl groups on the photocatalyst surface are reduced, forming an anion radical intermediate. The produced intermediate is oxidized by O 2 to produce H 2 O 2 and subsequently restores the carbonyl group. The high catalytic efficiency is ascribed to a photocatalytic redox cycle mediated by the radical anion, which not only promotes oxygen adsorption but also lowers the energy barrier of O 2 reduction reaction for H 2 O 2 generation. An apparent quantum yield of 14.28% at 420 ± 10 nm with a solar-to-chemical conversion efficiency of 0.92% is achieved. Moreover, we demonstrate that a mere 0.5 m 2 self-supported polyimide aerogel exposed to natural sunlight for 6 h yields significant H 2 O 2 production of 34.3 mmol m −2 . The photocatalytic redox cycle mediated by the anion radical intermediate promotes oxygen adsorption and lowers the energy barrier of O2 reduction reaction, thereby significantly improving the efficiency of H2O2 photosynthesis.

Organic light-emitting diodes (OLEDs) exploiting simple binary emissive layers (EMLs) blending only emitters and hosts have natural advantages in low-cost commercialization. However, previously reported OLEDs based on binary EMLs hardly simultaneously achieved desired comprehensive performances, e.g., high efficiency, low efficiency roll-off, narrow emission bands, and high operation stability. Here, we report a molecular-design strategy. Such a strategy leads to a fast reverse intersystem crossing rate in our designed emitter h -BNCO-1 of 1.79×10 5  s −1 . An OLED exploiting a binary EML with h -BNCO-1 achieves ultrapure emission, a maximum external quantum efficiency of over 40% and a mild roll-off of 14% at 1000 cd·m −2 . Moreover, h -BNCO-1 also exhibits promising operational stability in an alternative OLED exploiting a compact binary EML (the lifetime reaching 95% of the initial luminance at 1000 cd m −2 is ~ 137 h). Here, our work has thus provided a molecular-design strategy for OLEDs with promising comprehensive performance. Multi-resonance thermally activated delayed fluorescent emitters composed of only period-2 elements are important for achieving comprehensive performances. Here, authors report hybridization of organoboron-nitrogen and carbonyl groups in the emitter to achieve a long device operational stability.