Mechanism of extracellular electron transport and reactive oxygen mediated Sb(III) oxidation by Klebsiella aerogenes HC10.

Microbial oxidation and the mechanism of Sb(III) are key governing elements in biogeochemical cycling. A novel Sb oxidizing bacterium, Klebsiella aerogenes HC10, was attracted early and revealed that extracellular metabolites were the main fractions driving Sb oxidation. However, linkages between the extracellular metabolite driven Sb oxidation process and mechanism remain elusive. Here, model phenolic and quinone compounds, i.e., anthraquinone-2,6-disulfonate (AQDS) and hydroquinone (HYD), representing extracellular oxidants secreted by K. aerogenes HC10, were chosen to further study the Sb(III) oxidation mechanism. N2 purging and free radical quenching showed that oxygen-induced oxidation accounted for 36.78% of Sb(III) in the metabolite reaction system, while hydroxyl free radicals (·OH) accounted for 15.52%. ·OH and H2O2 are the main driving factors for Sb oxidation. Radical quenching, methanol purification and electron paramagnetic resonance (EPR) analysis revealed that ·OH, superoxide radical (O2•-) and semiquinone (SQ-•) were reactive intermediates of the phenolic induced oxidation process. Phenolic-induced ROS are one of the main oxidants in metabolites. Cyclic voltammetry (CV) showed that electron transfer of quinone also mediated Sb(III) oxidation. Part of Sb(V) was scavenged by the formation of the secondary Sb(V)-bearing mineral mopungite [NaSb(OH)6] in the incubation system. Our study demonstrates the microbial role of oxidation detoxification and mineralization of Sb and provides scientific references for the biochemical remediation of Sb-contaminated soil.

Underlying mechanism of Dendrobium huoshanense resistance to lead stress using the quantitative proteomics method.

Lead affects photosynthesis and growth and has serious toxic effects on plants. Here, the differential expressed proteins (DEPs) in D. huoshanense were investigated under different applications of lead acetate solutions. Using label-free quantitative proteomics methods, more than 12,000 peptides and 2,449 proteins were identified. GO and KEGG functional annotations show that these differential proteins mainly participate in carbohydrate metabolism, energy metabolism, amino acid metabolism, translation, protein folding, sorting, and degradation, as well as oxidation and reduction processes. A total of 636 DEPs were identified, and lead could induce the expression of most proteins. KEGG enrichment analysis suggested that proteins involved in processes such as homologous recombination, vitamin B6 metabolism, flavonoid biosynthesis, cellular component organisation or biogenesis, and biological regulation were significantly enriched. Nearly 40 proteins are involved in DNA replication and repair, RNA synthesis, transport, and splicing. The effect of lead stress on D. huoshanense may be achieved through photosynthesis, oxidative phosphorylation, and the production of excess antioxidant substances. The expression of 9 photosynthesis-related proteins and 12 oxidative phosphorylation-related proteins was up-regulated after lead stress. Furthermore, a total of 3 SOD, 12 POD, 3 CAT, and 7 ascorbate-related metabolic enzymes were identified. Under lead stress, almost all key enzymes involved in the synthesis of antioxidant substances are up-regulated, which may facilitate the scavenging of oxygen-free radical scavenging. The expression levels of some key enzymes involved in sugar and glycoside synthesis, the phenylpropanoid synthesis pathway, and the terpene synthesis pathway also increased. More than 30 proteins involved in heavy metal transport were also identified. Expression profiling revealed a significant rise in the expression of the ABC-type multidrug resistance transporter, copper chaperone, and P-type ATPase with exposure to lead stress. Our findings lay the basis for research on the response and resistance of D. huoshanense to heavy metal stress.

Harnessing in vivo synthesis of bioactive multiarylmethanes in Escherichia coli via oxygen-mediated free radical reaction induced by simple phenols.

BACKGROUND: Xanthenes and multi-aryl carbon core containing compounds represent different types of complex and condensed architectures that have impressive wide range of pharmacological, industrial and synthetic applications. Moreover, indoles as building blocks were only found in naturally occurring metabolites with di-aryl carbon cores and in chemically synthesized tri-aryl carbon core containing compounds. Up to date, rare xanthenes with indole bearing multicaryl carbon core have been reported in natural or synthetic products. The underlying mechanism of fluorescein-like arthrocolins with tetra-arylmethyl core were synthesized in an engineered Escherichia coli fed with toluquinol remained unclear. RESULTS: In this study, the Keio collection of single gene knockout strains of 3901 mutants of E. coli BW25113, together with 14 distinct E. coli strains, was applied to explore the origins of endogenous building blocks and the biogenesis for arthrocolin assemblage. Deficiency in bacterial respiratory and aromatic compound degradation genes ubiX, cydB, sucA and ssuE inhibited the mutant growth fed with toluquinol. Metabolomics of the cultures of 3897 mutants revealed that only disruption of tnaA involving in transforming tryptophan to indole, resulted in absence of arthrocolins. Further media optimization, thermal cell killing and cell free analysis indicated that a non-enzyme reaction was involved in the arthrocolin biosynthesis in E. coli. Evaluation of redox potentials and free radicals suggested that an oxygen-mediated free radical reaction was responsible for arthrocolins formation in E. coli. Regulation of oxygen combined with distinct phenol derivatives as inducer, 31 arylmethyl core containing metabolites including 13 new and 8 biological active, were isolated and characterized. Among them, novel arthrocolins with p-hydroxylbenzene ring from tyrosine were achieved through large scale of aerobic fermentation and elucidated x-ray diffraction analysis. Moreover, most of the known compounds in this study were for the first time synthesized in a microbe instead of chemical synthesis. Through feeding the rat with toluquinol after colonizing the intestines of rat with E. coli, arthrocolins also appeared in the rat blood. CONCLUSION: Our findings provide a mechanistic insight into in vivo synthesis of complex and condensed arthrocolins induced by simple phenols and exploits a quinol based method to generate endogenous aromatic building blocks, as well as a methylidene unit, for the bacteria-facilitated synthesis of multiarylmethanes.

Biochemical foundation of the aroma and antioxidant activity of Indian traditional rice landrace Maharaji and the effect of radiation-induced mutagenesis on its metabolome.

Maharaji rice, an aromatic variety with medium slender grains, is traditionally cultivated in the central regions of India. This study aimed to identify the biochemical compounds responsible for Maharaji rice's distinctive fragrance and enhance its agro-morphological traits through mutation breeding. Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) analysis, forty major metabolites were identified which may be responsible for its characteristic aroma. The bioactive compounds included terpenes, flavonoids, and amino acids. Maharaji brown rice extract exhibited potent radical scavenging activity. Radiation-induced mutation breeding improved the agro-morphological traits and also triggered biochemical diversification in different mutants. Maharaji Mutant-2 exhibited improved aroma due to higher abundance of aromatic compounds, improved yield and morphological characters as compared to the parent. This study, for the first time identifies the compounds associated with the characteristic aroma of Maharaji rice. Global metabolomics may, therefore, expedite the selection of mutants with suitable aroma and desirable biological properties.

Postoperative Intimal Hyperplasia: Review from My Research.

Postoperative intimal hyperplasia is the major cause of the vein graft occlusion. It is very important to establish an animal model for the start of research. After my vascular surgery residency in Japan, I started my research work on postoperative intimal hyperplasia at the University of Wisconsin-Madison. My research showed that endothelial injury and monocyte infiltration is the key for postoperative intimal hyperplasia, which is very similar to Ross' pathogenesis of atherosclerosis as an inflammatory disease. Focusing on postoperative intimal hyperplasia as an inflammatory disease, especially on tumor necrosis factor-α, FR-167653 (tumor necrosis factor-α suppressive agent, inhibitor of p 38 mitogen-activated protein kinase; Fujisawa Pharmaceutical Co., Ltd., Japan) is found to suppress postoperative intimal hyperplasia in a rat model by reducing serum monocyte chemoattractant protein-1 levels. However, FR-167653 is not commercially available today. Because endothelial injury is the first step of postoperative intimal hyperplasia, I investigated whether the free radical scavenger, edaravone (Radicut, Mitsubishi Tanabe Pharma Co., Japan), which alleviates the endothelial injury in vitro , can also suppress postoperative intimal hyperplasia. Moreover, the free radical scavenger edaravone (Radicut®, Mitsubishi Tanabe Pharma Co.) is also found to suppress postoperative intimal hyperplasia, by alleviating endothelial injury. In clinical settings, it is very important to detect postoperative intimal hyperplasia before its establishment. Hepatocyte growth factor is not only a hepatic growth factor but also a vascular endothelial growth factor. Recently, serum hepatocyte growth factor level was found to be a candidate biomarker for postoperative intimal hyperplasia in our rat model.

Nanoscale zero-valent iron/biochar composites containing persistent free radicals (PFRs) for degradation of p-nitrophenol.

Despite the vital roles of Fe0/biochar composites in the Fenton-like systems for eliminating pollutants that have been recognized, the contributions of persistent free radicals (PFRs) of carbon-based materials are typically overlooked. In this study, the high-PFR-containing biochar nanoiron composites were prepared (nZVI/500), and the in situ generation of hydroxyl radicals (·OH) and degradation of p-nitrophenol (PNP) were investigated. The results showed that nZVI/500 could effectively remove PNP in solution within the pH range of 3-8. Quantitative experiments of ·OH presented that, compared with low PFRs-containing composites, nZVI/500 could generate 64.6 µM ·OH in 60 min without any extra energy consumption. Mechanistic studies revealed that (1) both PFRs and Fe0 are able to utilize dissolved oxygen to generate H2O2 in situ; (2) PFRs can promote the cycling of Fe3+/Fe2+ in the system due to their strong electron exchange ability; and (3) PFRs directly transfer electrons to H2O2; therefore, the presence of PFRs accelerates the generation of ·OH in the system and facilitates the removal of PNP. This study provides an important theoretical basis and technical reference for expanding the application of PFR-rich carbon-based materials to remove environmental pollutants.

Free radical fragmentation and oxidation in the polar part of lysophospholipids: Results of the study of blood serum of healthy donors and patients with acute surgical pathology.

The interaction of reactive oxygen species with cell membrane lipids is usually considered in the context of lipid peroxidation in the nonpolar component of the membrane. In this work, for the first time, data were obtained indicating that damage to human cell membranes can occur in the polar part of lysophospholipids at the interface with the aqueous environment due to free radical fragmentation (FRF) processes. FRF products, namely 1-hexadecanoyloxyacetone (PAc) and 1-octadecanoyloxyacetone (SAc), were identified in human serum, and a GC-MS method was developed to quantify PAc and SAc. The content of FRF products in serum samples of 52 healthy donors was found to be in the range of 1.98-4.75 µmol/L. A linear regression equation, CPAc&SAc (µmol/L) = 0.51 + 0.064 × years, was derived to describe the relationship between age and content of FRF products. In 70 patients with acute surgical pathology in comparison with the control group of healthy donors, two distinct clusters with different concentration levels of FRF products were revealed. The first cluster: groups of 43 patients with various localized inflammatory-destructive lesions of hollow organ walls and bacterial translocation (septic inflammation) of abdominal cavity organs. These patients showed a 1.5-1.9-fold (p = 0.012) decrease in the total concentration of PAc and SAc in serum. In the second cluster: groups of 27 patients with ischemia-reperfusion tissue damage (aseptic inflammation), - a statistically significant increase in the concentration of FRF products was observed: in 2.2-4.0 times (p = 0.0001). The obtained data allow us to further understand the role of free-radical processes in the damage of lipid molecules. FRF products can potentially be used as markers of the degree of free-radical damage of hydroxyl containing phospholipids.

Reduction of oxidative damage in prostate tissue caused by radiation and/or chloroquine by apocynin.

Prostate damage can occur in men due to age and genetic factors, especially when exposed to external factors. Radiation (RAD) is a prominent factor leading to oxidative stress and potential prostate damage. Additionally, chloroquine (CQ), used in malaria treatment, can induce oxidative stress in a dose-dependent manner. Therefore, reducing and preventing oxidative damage in prostate tissue caused by external factors is crucial. Rats used in the study were divided into seven groups, CQ, apocynin (APO), RAD, CQ + APO, CQ + RAD, APO + RAD, CQ + APO + RAD. Subsequently, in vivo biochemical parameters of prostate tissues were examined, including reduced glutathione, lipid peroxidation, superoxide dismutase, glutathione reductase, glutathione peroxidase, glutathione-S-transferase activities, and total antioxidant status, total oxidant status, reactive oxygen species, oxidative stress index, advanced oxidation protein products and histologically. The in vivo results presented in our study showed that APO reduced oxidative stress and had a protective effect on prostate tissue in the CQ, RAD, and CQ + RAD groups as a results of biochemical and histological experiments. Additionally, in silico studies revealed a higher binding affinity of diapocynin to target proteins compared to APO. As a histological results, RAD and CQ alone or in combination did not induce damage in prostate tissues, whereas mild histopathological findings such as hyperemia and haemorrhage were observed in all APO-treated groups. The results suggest that the use of APO for the treatment of oxidative damage induced by CQ and RAD in rats.

The biochemical and histological experiments showed that apocynin (APO) has reducing effects of oxidative stress in prostate tissue caused by radiation and radiation + chloroquine.In silico models presented to possible inhibitory effects of APO for enzymes which are reason to the production of free radical.

Insights into free radicals scavenging, α-Amylase inhibition, cytotoxic and antifibrotic activities unveiled by Peganum harmala extracts.

BACKGROUND: Peganum harmala L. is used in traditional medicine to treat several health ailments. Hence, the present work aimed to investigate the DPPH free radical scavenging, α-amylase, cytotoxic, and antifibrotic effects of the hydrophilic extract and fixed oil obtained from P. harmala seeds. METHODS: The hydrophilic extract and fixed oil of P. harmala were assessed for their abilities to scavenge DPPH free radicals and inhibit α-amylase using reference bioassays. The cytotoxicity was assessed on several cancer and normal cell lines, including B16F1, Caco-2, COLO205, HeLa, Hep 3B and Hep G2, MCF-7, and HEK-293 T cells. The MTS assay was used to evaluate the antifibrotic capabilities utilizing the human hepatic stellate (LX-2) cell line. RESULTS: P. harmala plant fixed oil has potent DPPH free radical scavenging activity with an IC50 dose of 79.43 ± 0.08 µg/ml. Besides, the hydrophilic extract has a poor anti-α-amylase effect compared with the antidiabetic drug Acarbose, with IC50 doses of 398 ± 0.59 and 25.11 ± 1.22 µg/ml, respectively. In addition, the growth of MCF-7, Hep3B, HepG2, HeLa, COLO205, CaCo2, B16F1, and HeK293t was inhibited by P. harmala hydrophilic extract with IC50 doses of 121.34 ± 1.71, 268.3 ± 0.75, 297.20 ± 1.00, 155.60 ± 1.14, 150.01 ± 0.51, 308.35 ± 0.53, 597.93 ± 1.36, and 5.38 ± 0.99 µg/ml, respectively. In addition, at 1000 µg/ml, 5-Fluorouracil reduced fibrosis cells by 0.089%, while the hydrophilic extract decreased the number of LX-2 cells by 5.81%. CONCLUSION: P. harmala plant-fixed oil exhibits potential antioxidant properties. While the hydrophilic extract showed limited effectiveness as an anti-α-amylase agent and demonstrated notable cytotoxic effects against various tested cancer cell lines. Furthermore, this extract significantly reduces the number of LX-2 fibrotic cells. These findings emphasize the therapeutic potential of these products in managing various health disorders and warrant further investigation into their mechanisms of action and clinical applications.

Antioxidant properties of α-amino acids: a density functional theory viewpoint.

The antioxidant properties of 21 proteinogenic amino acids (AAs) and 3,4-dioxophenylanine (DOPA) have been studied in implicit water using density functional theory (DFT). All the calculations have been performed according to three oxidation mechanisms: (1) hydrogen-atom transfer (HAT); (2) single electron transfer followed by proton transfer (SET-PT); and (3) sequential proton-loss electron transfer (SPLET). As a result, five AAs with the highest antioxidant capacity have been established: DOPA, selenocysteine (Sec), tyrosine (Tyr), cysteine (Cys), and tryptophan (Trp). Also, global reactivity in terms of hardness/softness has been evaluated, as well as Fukui indices of local reactivity. Trp has been determined as the most reactive molecule, whereas selenium atom of Sec has been established as the most reactive atom. All the findings are in agreement with the recent literature on both experimental and theoretical studies of amino acids antioxidant activity. However, to the best of my knowledge, the calculations for one electron redox reactions of zwitterionic amino acids in implicit water have been performed for the first time.

Efficient Light-Based Bioprinting via Rutin Nanoparticle Photoinhibitor for Advanced Biomedical Applications.

Digital light processing (DLP) bioprinting, known for its high resolution and speed, enables the precise spatial arrangement of biomaterials and has become integral to advancing tissue engineering and regenerative medicine. Nevertheless, inherent light scattering presents significant challenges to the fidelity of the manufactured structures. Herein, we introduce a photoinhibition strategy based on Rutin nanoparticles (Rnps), attenuating the scattering effect through concurrent photoabsorption and free radical reaction. Compared to the widely utilized biocompatible photoabsorber tartrazine (Tar), Rnps-infused bioink enhanced printing speed (1.9×), interlayer homogeneity (58% less overexposure), resolution (38.3% improvement), and print tolerance (3× high-precision range) to minimize trial-and-error. The biocompatible and antioxidative Rnps significantly improved cytocompatibility and exhibited resistance to oxidative stress-induced damage in printed constructs, as demonstrated with human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs). The related properties of Rnps facilitate the facile fabrication of multimaterial, heterogeneous, and cell-laden biomimetic constructs with intricate structures. The developed photoinhibitor, with its profound adaptability, promises wide biomedical applications tailored to specific biological requirements.

Free radical mechanisms of ammonium sulfate as intensively used industrial materials on suppressing organic pollutants.

Organic free radicals are critical intermediates for the generation and inhibition of organic pollutants during industrial processes. Clarifying the free radical mechanism of pollutant inhibition is significant for their efficient control. Ammonium sulfate is intensively used in industrial materials to suppress organic pollutants. In this study, organic free radical intermediate species in metal-catalyzed reactions inhibited by ammonium sulfate were identified using continuous-wave electron paramagnetic resonance (EPR) spectroscopy, providing direct evidence for the free radical mechanisms of organic pollutants inhibition. The transverse (T2) and longitudinal (T1) relaxation time variations catalyzed by different metal catalysts in the presence of ammonium sulfate were compared using pulsed-wave EPR. Consequently, after the addition of ammonium sulfate, the observed increase in T2 suggests that ammonium sulfate leads to radical concentration reduction. A decrease in the T1 relaxation time suggests the enhanced interaction between organic radicals and metals, which is an obstacle to subsequent radical reactions. Therefore, ammonium sulfate dominantly changed the free radical intermediates species, concentrations, and their reactivity, and then inhibited the organic pollutants formations. The inhibition mechanisms of ammonium sulfate on metal-catalyzed pollutants were then proposed combining EPR analysis, X-ray characterization, and high-resolution mass spectrometry screening. As a result, (1) occupying the active sites of metal catalysis and (2) inhibiting free radical intermediates are the two main intrinsic inhibition mechanisms of ammonium sulfate. The findings provide new perspectives on the efficient inhibition of organic pollutants in industrial processes involving various metal catalysts.

Ozone-Assisted Cu-Based Catalysts for the Efficient Electro-Reforming Glycerol to Formic Acid.

Glycerol electrooxidation reaction (GOR) to produce value-added chemicals, such as formic acid, could make more efficient use of abundant glycerol and meet future demand for formic acid as a fuel for direct or indirect formic acid fuel cells. Non-noble metal Cu-based catalysts have great potential in electro-reforming glycerol to formic acid. However, the high activity, selectivity and stability of Cu based catalysts in GOR cannot be achieved simultaneously. Here, we used ozone-assisted electrocatalyst to convert glycerol to formic acid under alkaline conditions, the onset potential was reduced by 60 mV, the Faraday efficiency (FE) reached 95%. The catalyst has excellent stability within 300 h at the current density of 10 mA cm-2. The electron spin resonance proved that ozone produced superoxide anion during the GOR. In situ Raman spectroscopy, electrochemical studies showed that glycerol can be activated with ozone in GOR, and the C-C bond can be broken to reduce the polymerization of glycerol on the catalyst surface, so as to produce more formic acid at a lower voltage. Moreover, the removal of dissolved O3 from water can be up to 100% after 30 minutes of GOR reaction at a solubility of 50 mg L-1 as measured by UV-VIS spectrophotometry.

Nitrogen-doped carbon dots derived from ellagic acid and L-tyrosine for photothermal anticancer and anti-inflammation.

Photothermal therapy (PTT) of tumor would ineluctably cause oxidative stress and related inflammation in adjacent normal tissues, leading to a discounted therapeutic outcome. To address this issue, herein an innovative therapeutic strategy that integrates photothermal anticancer and normal cell protection is developed. A new type of nitrogen-doped carbon dot (ET-CD) has been synthesized in one step by hydrothermal method using ellagic acid and L-tyrosine as reaction precursors. The as-prepared ET-CD exhibits high photothermal conversion efficiency and good photothermal stability. After intravenous injection, ET-CD can accumulate at the tumor site and the hyperthermia generated under near infrared laser irradiation effectively ablates tumor tissues, thereby significantly inhibiting tumor growth. Importantly, owing to the inherited antioxidant activity from ellagic acid, ET-CD can remove reactive oxygen and nitrogen species produced in the body and reduce the levels of inflammatory factors induced by oxidative stress, so as to alleviate the damage caused by heat-induced inflammation to normal cells and tissues while photothermal anticancer. These attractive features of ET-CD may open the exploration of innovative therapeutic strategies to promote the clinical application of PTT.

Ca2+-promoted free radical grafting of whey protein to EGCG: As a novel nanocarrier for the encapsulation of apigenin.

Whey protein (WP) is often used as a delivery carrier due to its superior biological activity and nutritional value. Covalent binding of WP to epigallocatechin gallate (EGCG) can significantly improve the performance of WP in encapsulated materials. Nevertheless, the preparation of WP-EGCG covalent complexes still suffers from low grafting rates. Studies have shown that calcium ions (Ca2+) can modify the structure of proteins. We therefore explored the effect of calcium chloride (CaCl2) on the free radical grafting of EGCG and WP. The experimental results showed that the grafting rate of free radicals increased by 17.89% after adding Ca2+. Furthermore, the impact of WP-EGCG-Ca2+ covalent complex on the entrapment efficiency of apigenin (AP) was further examined, and the results revealed that the entrapment rate could reach 93.66% at an apigenin concentration of 0.2 mg/mL. Simulated gastrointestinal digestion showed that WP-EGCG-Ca2+ covalent complex could significantly improve the bioavailability of AP. The study provides new ideas to broaden the application of WP as a carrier for delivering bioactive substances.

Recent Progress in Free Radical Transformations of Allenamides.

Allenamides are special allenes, and the unique reactivity, selectivity (both stereoselective and regionally selective) and stability of allenamides have been widely studied. In this review, the development of the free radical transformation of allenamides over the last few years will be summarized. This review discusses in detail in three parts: intermolecular radical addition to C- X (X = N, S, O, Se) bonds, metal salt mediated cyclization of allenamides, and photocatalytic cyclization of allenamides. In addition, reasonable details of the mechanisms are provided for the vast majority of these transformations.

DMF-DMA catalyzed Synthesis, molecular docking, in-vitro, in-silico design, and binding free energy studies of novel thiohydantoin derivatives as antioxidant and antiproliferative agents targeting EGFR tyrosine kinase and aromatase cytochrome P450 enzyme.

A set of novels 2-thiohydantoin derivatives were synthesized and enaminone function was discussed at position 5 using DMFDMA catalyst which result in formation of pyrazole, isoxazole, benzoxazepine by using reagents such as hydrazine, hydroxylamine and 2-aminothiophenol. These newly synthesized compounds were evaluated for their antioxidant and antiproliferative activity. In vitro studies on the effect of 2-thiohydantoin on scavenging 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) confirmed the free radical scavenging and antioxidant activity of 2-thiohydantoin. The synthesized compounds show significant antioxidant activity. The in vitro antitumor activity of 2-thiohydantoin on MCF7 (breast) and PC3 cells (prostate) was evaluated using MTT assay. Some of the synthesized compounds show significant to moderate antiproliferative properties compared to reference drug erlotinib. Among all, compound 4a exhibit potent antitumor properties against MCF7 and PC3 cancer cell lines with IC50 = 2.53 ± 0.09 /ml & with IC50 = 3.25 ± 0.12 µg/ml respectively and has potent antioxidant activity with IC50 = 10.04 ± 0.49 µg/ml.

Efficient Transformation of Water Vapor into Hydrogen by Dielectric Barrier Discharge Loaded with Bamboo Carbon Bed Structured by Fibrous Material.

A new method of efficiently transforming water vapor into hydrogen was investigated by dielectric barrier discharge (DBD) loaded with bamboo carbon bed structured by fibrous material in an argon medium. Hydrogen productivity was measured in three different reactors: a non-loaded DBD (N-DBD), a bamboo carbon (BC) bed DBD (BC-DBD), and a quartz wool (QW)-loaded BC DBD (QC-DBD). The effects of the quality ratio of BC to QW and relative humidity on hydrogen productivity were also investigated in QC-DBD at various flow rates. The reaction process and mechanism were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy, N2 physisorption experiments, infrared spectroscopy, and optical emission spectroscopy. A new reaction pathway was developed by loading BC into the fibrous structured material to activate the reaction molecules and capture the O-containing groups in the DBD reactor. A hydrogen productivity of 17.3 g/kWh was achieved at an applied voltage of 5 kV, flow rate of 4 L/min, and 100% relative humidity (RH) in the QC-DBD with a quality ratio of BC to QW of 3.0.

Physical properties and antioxidant activity of curcumin­zinc metal-organic frameworks.

Metal-organic frameworks (MOFs) offer diverse applications in the food industry, facilitating loading, protection, and controlled release of functional ingredients despite encountering loading capacity and functional activity limitations. This study focuses on curcumin­zinc MOFs, harnessing curcumin's renowned health benefits and zinc to enhance pharmacological properties. We evaluated their synthesis efficiency, stability under varying conditions (pH, salt concentration, temperature), loading and antioxidant capacity. The results showed that microwave synthesis yielded MOFs with a 23.2 ± 4.5% yield, stable within pH 4-10, gradually decomposing in PBS. DPPH, ABTS, and H2O2 assays revealed varying free radical scavenging abilities. MOFs disintegrate in either acidic environments or contain H2O2 (at a concentration threshold of 10 µM). Post-disintegration, these MOFs significantly inhibiting the secretion of TNF-α by RAW264.7 cells induced by LPS. These findings highlight the potential of novel curcumin­zinc MOF materials for nutrient delivery, addressing challenges in effectively delivering functional ingredients.

Dual-Temperature/pH-Sensitive Hydrogels with Excellent Strength and Toughness Crosslinked Using Three Crosslinking Methods.

Hydrogels are widely used as excellent drug carriers in the field of biomedicine. However, their application in medicine is limited by their poor mechanical properties and softness. To improve the mechanical properties of hydrogels, a novel triple-network amphiphilic hydrogel with three overlapping crosslinking methods using a one-pot free-radical polymerization was synthesized in this study. Temperature-sensitive and pH-sensitive monomers were incorporated into the hydrogel to confer stimulus responsiveness, making the hydrogel stimuli-responsive. The successful synthesis of the hydrogel was confirmed using techniques, such as proton nuclear magnetic resonance spectroscopy (1H NMR), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). In order to compare and analyze the properties of physically crosslinked hydrogels, physically-chemically double-crosslinked hydrogels, and physically-chemically clicked triple-crosslinked hydrogels, various tests were conducted on the gels' morphology, swelling behavior, thermal stability, mechanical properties, and drug loading capacity. The results indicate that the triple-crosslinked hydrogel maintains low swelling, high mechanical strength, and good thermal stability while not significantly compromising its drug delivery capability.