Overlooked role of void-nanoconfined effect in emerging pollutant degradation: Modulating the electronic structure of active sites to accelerate catalytic oxidation.

The efficient removal of emerging pollutant from water is the ultimate frontiers of advanced oxidation processes (AOPs), yet it is challenging to obtain higher catalytic activity and oxidation rate. Herein, a sustainable solution was proposed by optimizing the curvature of confined structure to modulate the electronic state of the active sites in nanochannels for improving the catalytic activity. In addition, the confined effect can enhance the oxidation rate by shorting the mass transfer of active species and pollutants. A void-nanoconfined nanoreactor was prepared by loading Fe2O3 into the nanochannels (<5 nm) of the hollow carbon sphere. An enhancement of 3 orders of magnitude was obtained in the degradation rate constant of void-nanoconfined catalytic system toward sulfamethoxazole (SMX) (6.25 min-1) compared with the non-confined system. The kinetics enhancement was attributed to the larger electron potential difference between the outer and inner nanochannel caused by the curvature increase of carbon sphere, accelerating the electron transfer, so that the energy barrier of SMX degradation reaction was reduced by 31 kcal/mol with the assistance of confinement energy. Importantly, the NC-IN/PDS system exhibited outstanding removal efficiency for the actual river water using a continuous flow reactor. This work provides a new insight into designing an efficient and stable catalytic nanoreactor, enriching the domain of advanced wastewater treatment strategies.

Facilitating Proton Coupled Electron Transfer Reaction through the Interfacial Micro Electric Field with Fe─N4 ─C in FeMOFs Glass.

The proton-coupled electron transfer(PCET) reaction plays a crucial role in the chemical transformation process andhas become one of the most concerned elementary reactions. However, the complex kinetics of PCET reaction, which requires the simultaneous transfer of protons and electrons, leads to the dilemma that thermodynamics and kinetics cannot bebalanced and restricts its further development. In this, an interface micro-electric field (IMEF) basedon Fe─N4 in FeMOFs (Fe-Based Metal-Organic Frameworks) glass is designed tosynchronize proton/electron interface behavior for the first time to realizeefficient PCET reaction and optimize reaction thermodynamics and kinetics. The IMEF facilitates the separation of photogenerated electrons and holes, and accelerates Fe(III)/Fe(II) cycle. Driven by near-surface electric field force, the protons near surfacemigrate to Fe sites and participate in Fe(IV)═O formation and reaction, lowering the reaction energy barrier. Based on the interface regulation ofIMEF, a high-efficiency PCET reaction is realized, and kinetic reactionrate constant of photocatalytic oxidation of emerging contaminants is increasedby 3.7 times. This study highlights a strategy for IMEFs to modulate PEC Treactions for a wide range of potential applications, including environmental and ecological applications.

A Bioorthogonal Decaging Chemistry of N-Oxide and Silylborane for Prodrug Activation both In Vitro and In Vivo.

Bioorthogonal decaging chemistry with both fast kinetics and high efficiency is highly demanded for in vivo applications but remains very sporadic. Herein, we describe a new bioorthogonal decaging chemistry between N-oxide and silylborane. A simple replacement of "C" in boronic acid with "Si" was able to substantially accelerate the N-oxide decaging kinetics by 106 fold (k2: up to 103 M-1 s-1). Moreover, a new N-oxide-masked self-immolative spacer was developed for the traceless release of various payloads upon clicking with silylborane with fast kinetics and high efficiency (>90%). Impressively, one such N-oxide-based self-assembled bioorthogonal nano-prodrug in combination with silylborane led to significantly enhanced tumor suppression effects as compared to the parent drug in a 4T1 mouse breast tumor model. In aggregate, this new bioorthogonal click-and-release chemistry is featured with fast kinetics and high efficiency and is perceived to find widespread applications in chemical biology and drug delivery.

Lipid-based nanoparticles for cancer immunotherapy.

As the fourth most important cancer management strategy except surgery, chemotherapy and radiotherapy, cancer immunotherapy has been confirmed to elicit durable antitumor effects in the clinic by leveraging the patient's own immune system to eradicate the cancer cells. However, the limited population of patients who benefit from the current immunotherapies and the immune related adverse events hinder its development. The immunosuppressive microenvironment is the main cause of the failure, which leads to cancer immune evasion and immunity cycle blockade. Encouragingly, nanotechnology has been engineered to enhance the efficacy and reduce off-target toxicity of their therapeutic cargos by spatiotemporally controlling the biodistribution and release kinetics. Among them, lipid-based nanoparticles are the first nanomedicines to make clinical translation, which are now established platforms for diverse areas. In this perspective, we discuss the available lipid-based nanoparticles in research and market here, then describe their application in cancer immunotherapy, with special emphasis on the T cells-activated and macrophages-targeted delivery system. Through perpetuating each step of cancer immunity cycle, lipid-based nanoparticles can reduce immunosuppression and promote drug delivery to trigger robust antitumor response.

Unraveling the single-atom Fe-N4 catalytic site selectivity generate singlet oxygen via activation of persulfate: Polarizing electric fields changes the electron transfer pathway.

Single-atom catalysts have been proved to be an effective material for the removal of organic pollutants from water and wastewater, and yet, the relationship between their internal structures and their roles still remains elusive. In this work, a catalyst Fe (MIL)-SAC with single-atom Fe-N4 active site was prepared. Fe (MIL)-SAC/Peroxydisulfate (PDS) system was able to achieve complete degrade of the Sulfamethoxazole (SMX) with kobs at 0.466 min-1, which was faster than the Fenton system under the same conditions (kobs = 0.422 min-1) and 16 times faster than Fe (MIL) (kobs = 0.029 min-1). Density functional calculations reveal that the Fe-N4 structure will affect the electron transport path and lead to selective generation of 1O2 by triggering S-O breakage and O-O polarization in PDS. Furthermore, Fe (MIL)-SAC/PDS system exhibits strong resistance to common influencing factors and has good application prospects. This work provides a new approach for the selectively generation of 1O2 for the efficient treatment of organic pollutants in aqueous environment.

Multi-omic analysis of the extension of broccoli quality during storage by folic acid.

INTRODUCTION: Folic acid (FA) is a critical metabolite in all living organisms and an important nutritional component of broccoli. Few studies have been conducted on the impact of an exogenous application of FA on the postharvest physiology of fruits and vegetables during storage. In this regard, the mechanism by which an exogenous application of FA extends the postharvest quality of broccoli is unclear. OBJECTIVE: This study utilized a multicomponent analysis to investigate how an exogenous application of FA effects the postharvest quality of broccoli. METHODS: Broccoli was soaked in 5 mg/L FA for 10 min and the effect of the treatment on the appearance and nutritional quality of broccoli was evaluated. These data were combined with transcriptomic, metabolomic, and DNA methylation data to provide insight into the potential mechanism by which FA delays senescence. RESULTS: The FA treatment inhibited the yellowing of broccoli during storage. CHH methylation was identified as the main type of methylation that occurs in broccoli and the FA treatment was found to inhibit DNA methylation, promote the accumulation of endogenous FA and chlorophyl, and inhibit ethylene biosynthesis in stored broccoli. The FA treatment also prevented the formation of off-odors by inhibiting the degradation of glucosinolate. CONCLUSIONS: FA treatment inhibited the loss of nutrients during the storage of broccoli, delayed its yellowing, and inhibited the generation of off-odors. Our study provides deeper insight into the mechanism by which the postharvest application of FA delays postharvest senescence in broccoli and provides the foundation for further studies of postharvest metabolism in broccoli.

Whole-transcriptome RNA sequencing reveals changes in amino acid metabolism induced in harvested broccoli by red LED irradiation.

Whole-transcriptomic profiling combined with amino acid analysis were conducted in order to gain a better understanding of global changes in amino acid metabolism induced in broccoli by red LED irradiation. The results showed that the contents of almost all 16 amino acids in postharvest broccoli were maintained under red LED illumination. The red LED irradiation enhanced the anabolism of amino acid, including the biosynthesis of aromatic amino acids by upregulating the genes' expression in the shikimate pathway, as well as by upregulating the genes' expression which encoding biosynthetic enzymes in the branched-chain amino acid biosynthesis pathway. Red LED irradiation induced the expression of genes encoding aspartate aminotransferase, which plays a role in Asp synthesis, aspartate kinase, which functions in aspartate metabolism, and a cytoplasmic aspartate aminotransferase that converts 2-Oxoglutarate into Glu. Genes encoding imidazole glycerol-phosphate synthase and histidinol-phosphatase, which function in the His biosynthesis pathway, were also upregulated. According to our results, red LED irradiation delays broccoli's yellowing and senescence by regulating amino acid metabolism. These results enhance our understanding of the role of amino acid metabolism in the senescence of broccoli and the mechanism of red LED irradiation to alter amino acid metabolism in harvested broccoli.

Dichloromethanol but not difluoromethanol as a viable surrogate of carbon monoxide for prodrug design.

Herein, we demonstrate that dichloromethanol but not difluoromethanol is a viable surrogate of carbon monoxide for prodrug design. A proof of concept was established by the successful development of a ROS-responsive carbon monoxide prodrug, presenting specific CO release in response to endogenous ROS in cells.

Photoclick and Release: Co-activation of Carbon Monoxide and a Fluorescent Self-reporter, COS or Sulfonamide with Fast Kinetics.

Bioorthogonal prodrugs with both fast reaction kinetics and multiple outputs are highly desirable but are only found sporadically. Herein, we report a novel photoclick-and-release strategy for the co-activation of carbon monoxide and a self-reporter, carbonyl sulfide, or sulfonamide with fast reaction kinetics (k: 1.4-22.6 M-1 s-1 ). Such a photoclick-and-release strategy was successfully applied in live cells to deliver carbon monoxide and a fluorescent self-reporter, both of which exhibited pronounced antiproliferative activity against 4T1 cancer cells. It is conceivable that this photoclick-and-release strategy could find applications in other fields, in which a controlled bond cleavage is preferred.

Exploring degradation properties and mechanisms of emerging contaminants via enhanced directional electron transfer by polarized electric fields regulation in Fe-N4-Cx.

Heterogeneous catalysis offers an opportunity to overcome the low efficiency and secondary pollution limitations of emerging contaminants (ECs) purification technologies, but it is still challenging to regulate electron directed transport for achieving high catalysis efficiency and selectivity due to insufficient understanding of the electron transfer pathways and behavioral mechanisms during its catalysis. Here, by tuning the defects of the C-N coordination of the support, the polarized electric field (PEF) characteristics are changed, which in turn affects the electron transport behavior. The results show that the charge offset on Fe-N4-Cx forms a PEF, which will induce directional electron transport. After the quantitative structure-activity relationship (QSAR) fitting analysis, the greater the degree of C-N defects, the higher the intensity of the PEF, which in turn enhances the electron transport and promotes the catalytic behavior. In addition, the surface pyrrole N site can adsorb enrofloxacin (ENR) and enrich it on the surface. This can reduce the transport distance of reactive oxygen species (ROS) to synergize catalysis and adsorption, resulting in rapid degradation of ECs. Combined with liquid chromatograph mass spectrometer (LC-MS) results and theoretical calculations, five degradation pathways of ENR were speculated, mainly including the oxidation of piperazine and the cleavage of the quinolone ring. This work proposes a novel PEF regulation strategy and explores its mechanism for safe treatment of ECs.

A novel polydopamine-modified metal organic frameworks catalyst with enhanced catalytic performance for efficient degradation of sulfamethoxazole in wastewater.

In this study, a novel polydopamine (PDA)-modified metal organic frameworks (MOFs) catalyst (MIL/PDA) was successfully fabricated to activate persulfate (PS) for the degradation of sulfamethoxazole (SMX) in wastewater. The experimental results indicated that PDA-modified catalyst exhibited superior catalytic performance and enhanced the degradation of SMX (91.5%) compared to pure MOFs. The physical-chemical properties of the MIL/PDA catalyst were comprehensively characterized, and the applications in the catalytic degradation of SMX were evaluated. It was found that the modification of PDA enhanced the electron transfer, while promoting the redox cycle of Fe(III)/Fe(II), which in turn boosted the production of active oxygen species. Furthermore, MIL/PDA showed high stability and reusable performance over multiple cycles. Both radical and non-radical pathways were jointly involved in the activation process of PS were confirmed by quenching experiments combined with electron paramagnetic resonance (EPR). Based on this, the possible mechanism of the catalytic reaction was investigated. Finally, five degradation pathways of SMX degradation were proposed according to the results of liquid chromatography-mass spectrometry (LC-MS). This work provided a new insight into the design of novel and efficient heterogeneous catalysts for advanced wastewater treatment.

Modulated construction of Fe-based MOF via formic acid modulator for enhanced degradation of sulfamethoxazole：Design, degradation pathways, and mechanism.

Metal-organic frameworks (MOFs) have attracted more attention because of their excellent environmental catalytic capabilities. Modulation approach as an advanced assistant strategy is vital essential to enhancing the performance of MOFs. In this study, the modulated method was used to successfully synthesize a group of Fe-based MOFs, with formic acid as the modulator on the synthesis mixture. The most modulated sample Fe-MOFs-2 exhibit high specific surface areas and higher catalytic activity, which could effectively degrade SMX via PS activation, with almost 95% removal efficiency within 120 min. The results revealed that the % RSE of modulated Fe-MOFs-2 increased from 2.31 to 3.27 when compared with the origin Fe-MOFs. This may be due to the addition of formic acid induces the formation of more coordinatively unsaturated metal sites in the catalyst, resulting in structural defects. In addition, the quenching experiment and EPR analysis verified SO4-·and·OH as the major active free radicals in the degradation process. Modulated Fe-MOFs-2 demonstrated good reusability and stability under fifth cycles. Finally, four possible degradation pathways and catalytic mechanism of Fe-MOFs-2 was tentatively proposed. Our work provides insights into the rational design of modulated Fe-MOFs as promising heterogeneous catalysts for advanced wastewater treatment.

Targeted degradation of TBBPA using novel molecularly imprinted polymer encapsulated C-Fe-Nx nanocomposite driven from MOFs.

To improve the efficacy of organic pollutant removal using sulfate radicals, we designed MIP@C-Fe-Nx, a molecularly imprinted material capable of targeting the degradation of tetrabromobisphenol A (TBBPA), which can be used as both adsorbent and catalyst to recognize and degrade Tetrabromobisphenol A (TBBPA) accurately, and the final removal rate of TBBPA can reach 104.6 mg·g-1. Based on the synergistic effects of MIP@C-Fe-Nx on the excellent organic pollutant recognition and catalytic performance, low concentrations of TBBPA can be pre-targeted, concentrated, and fixed on the surface of MIP, and degraded simultaneously in-situ by·OH and SO4•- which are produced by activating PS with C-Fe-Nx. Recognition experiments demonstrated that MIPs had perfect performance in recognizing and adsorbing TBBPA and debromination intermediates. The DFT calculations and HPLC-MS analysis indicated that MIP@C-Fe-Nx had a targeted recognition and accumulation for TBBPA and debromination intermediates, for example, dibromobisphenol A, monobromobisphenol A, and bisphenol A, thus avoid the formation of toxic intermediates causing secondary contamination.

Fe-N-C catalyst with Fe-NX sites anchored nano carboncubes derived from Fe-Zn-MOFs activate peroxymonosulfate for high-effective degradation of ciprofloxacin: Thermal activation and catalytic mechanism.

Developing high-efficient catalysts is crucial for activating peroxymonosulfate (PMS). Fe-N-C catalysts exhibit excellent performance for PMS activation because of the contribution of doped N, Fe-Nx and Fe3C sites. In our work, a series of Fe-N-C catalysts with high-performance was obtained by pyrolyzing Fe-Zn-MOFs precursors. During pyrolysis process, the change of chemical bonds and formation of active sites in the precursor were elucidated by characterization analysis and related catalytic experiments. Graphitic N, Fe-Nx and Fe3C were confirmed to activate PMS synergistically for ciprofloxacin (CIP) degradation. Besides, the catalytic performance was proportional to the amount of doped iron and calcination temperature. Moreover, the Fe-N-C-3-800/PMS system not only displayed good recycling performance, but also had high anti-interference ability. Integrated with quenching and electron paramagnetic resonance (EPR) experiments, a non-radical pathway dominated by 1O2 was proposed. Furthermore, PMS could bond to Fe-N-C-3-800 to form intermediate for charge transfer, thus accelerate electron transfer between CIP and PMS to realize degradation of CIP. Six main pathways of CIP degradation were proposed, which include bond fission of N-C on piperazine ring and direct oxidation of CIP. This study provided a new idea for the design of heterogeneous carbon catalysts in advanced oxidation field.

Enhanced electro-Fenton catalytic performance with in-situ grown Ce/Fe@NPC-GF as self-standing cathode: Fabrication, influence factors and mechanism.

Heterogeneous electro-Fenton (E-F) is considered as an attractive technique for efficient removal of refractory organic pollutants in wastewater. The regeneration of FeII and catalyst reusability are key issues for effective and sustainable degradation. Developing binder-free iron phase/carbon composite cathode is a feasible strategy. In this work, the stable Ce/Fe-nanoporous carbon modified graphite felt electrode (Ce/Fe@NPC-GF) was fabricated using in situ solvothermal method and subsequent carbonization treatment, which worked as the cathode in a heterogeneous electro-Fenton system to degrade sulfamethoxazole. The electrocatalytic activity was significantly improved with doping of Ce. It was found that mesoporous Ce/Fe@NPC-GF cathode demonstrated high oxygen reduction activity and low resistance. The co-existence of FeⅡ/FeⅢ and CeⅢ/CeⅣ redox couples enhanced remarkably interfacial electron transfer, promoting in-situ H2O2 generation and decomposition, sequentially boosting the production of reactive radicals (·OH and ·O2-). Under 20 mA and pH 3, Sulfamethoxazole (SMX) was basically degraded in 120 min, and the removal rate was satisfactory in wide pH (2-6). After 8 cycles, the electrode could still maintain high stability and outstanding catalytic capacity. This work displayed a novel in-situ preparation method of composite cathode with excellent catalytic performance in E-F system, which offered inspiration for developing efficient heterogeneous electro-Fenton cathode material.

Effect of folic acid on the postharvest physiology of broccoli during storage.

The objective of the present study was to explore the effect of folic acid on the postharvest physiology of broccoli placed in storage. Broccoli heads were immersed in 5 mg L-1 folic acid for 10 min, then stored at 20 ± 1 °C for 4 days. Results indicated that the postharvest treatment of broccoli with folic acid decreased the rate of flower opening and yellowing, inhibited weight loss, reduced the level of respiration, as well as ethylene generation. Folic acid-treated broccoli maintained their level of chlorophyll, total soluble solids, vitamin C, total phenolics, flavonoids, glucosinolate, and folic acid. Treated broccoli also exhibited reduced accumulation of malondialdehyde (MDA) and reactive oxygen species (ROS). Concomitantly, antioxidant enzyme activity and corresponding gene expression were also enhanced. In contrast, chlorophyll-degrading enzyme gene expression was suppressed. These results indicated that folic acid treatment of broccoli could be used to prolong shelf-life.

Role of Nanocrystallites of Al-Based Glasses and H2O2 in Degradation Azo Dyes.

Al-based metallic glasses have a special atomic structure and should have a unique degradation ability in azo dye solutions. The Al88Ni9Y3 (Y3), Al85Ni9Y6 (Y6) and Al82Ni9Y9 (Y9) glassy ribbons are melt spun and used in degrading methyl orange (MO) azo dye solution with adding H2O2. With increasing cY, the as-spun ribbons have an increasing GFA (glass formability) and gradually decreased the degradation rate of MO solution. TEM (transmission electron microscopy) results show that the Y3 ribbon has nano-scale crystallites, which may form the channels to transport elements to the surface for degrading the MO solution. After adding H2O2, the degradation efficiency of Al-based glasses is improved and the Y6 ribbon has formed nano-scale crystallites embedded in the amorphous matrix and it has the largest improvement in MO solution degradation. These results indicate that forming nano-scale crystallites and adding H2O2 are effective methods to improve the degradation ability of Al-based glasses in azo dye solutions.

High MB Solution Degradation Efficiency of FeSiBZr Amorphous Ribbon with Surface Tunnels.

The as spun amorphous (Fe78Si9B13)99.5Zr0.5 (Zr0.5) and (Fe78Si9B13)99Zr1 (Zr1) ribbons having a Fenton-like reaction are proved to bear a good degradation performance in organic dye wastewater treatment for the first time by evaluating their degradation efficiency in methylene blue (MB) solution. Compared to the widely studied (Fe78Si9B13)100Zr0 (Zr0) amorphous ribbon for degradation, with increasing cZr (Zr atomic content), the as-spun Zr0, Zr0.5 and Zr1 amorphous ribbons have gradually increased degradation rate of MB solution. According to δc (characteristic distance) of as-spun Zr0, Zr0.5 and Zr1 ribbons, the free volume in Zr1 ribbon is higher Zr0 and Zr0.5 ribbons. In the reaction process, the Zr1 ribbon surface formed the 3D nano-porous structure with specific surface area higher than the cotton floc structure formed by Zr0 ribbon and coarse porous structure formed by Zr0.5 ribbon. The Zr1 ribbon's high free volume and high specific surface area make its degradation rate of MB solution higher than that of Zr0 and Zr0.5 ribbons. This work not only provides a new method to remedying the organic dyes wastewater with high efficiency and low-cost, but also improves an application prospect of Fe-based glassy alloys.

Effect of methyl jasmonate on the quality of harvested broccoli after simulated transport.

The effect of simulated transport vibration on the quality of broccoli and the ability of methyl jasmonate (MeJA) to ameliorate vibration damage in broccoli were investigated. Results indicated that transport injury, simulated by vibrational stress, promoted the deterioration in broccoli quality during subsequent storage. Treatment of broccoli with methyl jasmonate (MeJA), however, effectively ameliorated the impact of vibrational injury, maintained the appearance quality and delayed the yellowing and senescence of florets after simulated transportation stress. The effect of the MeJA may be related to of its ability to suppress the accumulation of reactive oxygen species, enhance vitamin C content, and induce antioxidant gene expression and enzyme activity, as well as suppress chlorophyll-degrading enzyme activity and gene expression. Overall, the MeJA treatment inhibited the adverse physiological changes that occur in broccoli as a result of vibrational and mechanical injury. Thus, MeJA has the potential to be used to decrease stress-induced reductions in the postharvest quality of horticultural crops that occur during transport and storage, thus, prolonging their shelf life.

Integrated Analysis of Transcriptomic and Metabolomic Data Reveals the Mechanism by Which LED Light Irradiation Extends the Postharvest Quality of Pak-choi (Brassica campestris L. ssp. chinensis (L.) Makino var. communis Tsen et Lee).

Low-intensity (10 µmol m-2 s-1) white LED (light-emitting diode) light effectively delayed senescence and maintained the quality of postharvest pakchoi during storage at 20 °C. To investigate the mechanism of LED treatment in maintaining the quality of pakchoi, metabolite profiles reported previously were complemented by transcriptomic profiling to provide greater information. A total of 7761 differentially expressed genes (DEGs) were identified in response to the LED irradiation of pak-choi during postharvest storage. Several pathways were markedly induced by LED irradiation, with photosynthesis being the most notable. More specifically, porphyrin and chlorophyll metabolism and glucosinolate biosynthesis were significantly induced by LED irradiation, which is consistent with metabolomics reported previously. Additionally, chlorophyllide a, chlorophyll, as well as total glucosinolate content was positively induced by LED irradiation. Overall, LED irradiation delayed the senescence of postharvest pak-choi mainly by activating photosynthesis, inducting glucosinolate biosynthesis, and inhibiting the down-regulation of porphyrin and chlorophyll metabolism pathways. The present study provides new insights into the effect and the underlying mechanism of LED irradiation on delaying the senescence of pak-choi. LED irradiation represents a useful approach for extending the shelf life of pak-choi.