An insight into the antioxidant activities and the exploration of record high quantities of quercetin and luteolin in the plant parts of Myxopyrum smilacifolium (wall.) Blume.

This study attempts to reveal antioxidants in the plant parts of Myxopyrum smilacifolium (Wall.) Blume using antioxidant assays and LC-MS/MS analysis. Methanol is the most effective solvent for collecting antioxidants. The roots-derived methanol extract demonstrates the greatest antioxidant activity, corresponding to the extremely low IC50 values of 16.39 µg/mL and 19.80 µg/mL for DPPH and ABTS radicals, respectively. The high phenolic and flavonoid contents are the primary reason for outstanding total antioxidant capacity (TAC; i.e. 247.73 ± 1.62 mg GA/g or 163.93 ± 0.83 mg AS/g) of the root extract. LC-MS/MS quantification of five phenolic compounds reveals exceptionally high amounts of quercetin and luteolin in the root extract, ranging from 238.86 ± 5.74 to 310.99 ± 1.44 µg/g and from 201.49 ± 7.84 to 234.10 ± 2.54 µg/g, respectively, in the root-derived methanol extract. The achievement highlights M. smilacifolium as a promising source of natural antioxidants for large-scale medical applications.

A glucose-assisted redox hydrothermal route to prepare a Mn-doped CeO2 catalyst for the total catalytic oxidation of VOCs.

In this study, a novel glucose-assisted redox hydrothermal method has been presented to prepare an Mn-doped CeO2 catalyst (denoted as Mn-CeO2-R) for the first time. The obtained catalyst contains uniform nanoparticles with a small crystallite size, a large mesopore volume, and rich active surface oxygen species. Such features collectively contribute to improving the catalytic activity for the total catalytic oxidation of methanol (CH3OH) and formaldehyde (HCHO). Interestingly, the large mesopore volume feature of the Mn-CeO2-R samples could be considered an essential factor to eliminate the diffusion limit, favoring the total oxidation of toluene (C7H8) at high conversion. Therefore, the Mn-CeO2-R catalyst outperforms both bare CeO2 and conventional Mn-CeO2 catalysts with T 90 values of 150 °C and 178 °C for HCHO and CH3OH, respectively, and 315 °C for C7H8, at a high GHSV of 60 000 mL g-1 h-1. Such robust catalytic activities signify a potential utilization of Mn-CeO2-R for the catalytic oxidation of volatile organic compounds (VOCs).

An overview on recent progress in photocatalytic air purification: Metal-based and metal-free photocatalysis.

Air pollution is becoming a distinctly growing concern and the most pressing universal problem as a result of increased energy consumption, with the multiplication of the human population and industrial enterprises, resulting in the generation of hazardous pollutants. Among these, carbon monoxide, nitrogen oxides, Volatile organic compounds, Semi volatile organic compounds, and other inorganic gases not only have an adverse impact on human health both outdoors and indoors, but have also substantially altered the global climate, resulting in several calamities around the world. Thus, the purification of air is a crucial matter to deal with. Photocatalytic oxidation is one of the most recent and promising technologies, and it has been the subject of numerous studies over the past two decades. Hence, the photocatalyst is the most reassuring aspirant due to its adequate bandgap and exquisite stability. The process of photocatalysis has provided many benefits to the atmosphere by removing pollutants. In this review, our work focuses on four main themes. Firstly, we briefly elaborated on the general mechanism of air pollutant degradation, followed by an overview of the typical TiO2 photocatalyst, which is the most researched photocatalyst for photocatalytic destruction of gaseous VOCs. The influence of operating parameters influencing the process of photocatalytic oxidation (such as mass transfer, light source and intensity, pollutant concentration, and relative humidity) was then summarized. Afterwards, the progress and drawbacks of some typical photoreactors (including monolithic reactors, microreactors, optical fiber reactors, and packed bed reactors) were described and differentiated. Lastly, the most noteworthy coverage is dedicated to different types of modification strategies aimed at ameliorating the performance of photocatalysts for degradation of air pollutants, which were proposed and addressed. In addition, the review winds up with a brief deliberation for more exploration into air purification photocatalysis.

Recent progress on elemental sulfur based photocatalysts for energy and environmental applications.

The growing needs of the rising population and blatant misuse of resources have contributed enormously to environmental problems. Among the various methods, photocatalysis has emerged as one of the effective remediation methods. The continuous search for effective photocatalysts that can be made from abundant, cheap, non-toxic materials is going on. Although sulfur is a known insulator, recent sulfur use as a visible light photocatalyst has ushered a new era in this direction. Sulfur is a non-toxic, cheap, and abundant photocatalyst, exhibiting significant photocatalytic properties. But, hydrophobicity, poor light-harvesting and high recombination rate of charge carriers in elemental sulfur photocatalyst are some of the major drawbacks of the elemental sulfur photocatalyst. The photocatalytic activity of sulfur as a single element was low, but various methods such as nanoscaling, heterojunction formation, doping and surface modifications have been used to enhance it. The review highlights sulfur's crystal structure, electronic and optical properties, and morphological changes, making it an excellent visible light photocatalyst. The article points to the limitations of sulfur as a single photocatalyst and various strategies to improve the shortcomings. More recently, there has been an emphasis on the synthesis of metal-free photocatalysts. This review provides its readers with a comprehensive detail of sulfur being used as a dopant in improving the photocatalytic properties of metal-free photocatalysts and their environmental remediation use. Finally, the conclusion and future perspectives for sulfur-based nanostructures are presented.

Structural Characterization of Mannoglucan Isolated from Ophiocordyceps sobolifera and Its Antioxidant Activities.

A novel polysaccharide structure (PS-T80) was collected from Ophiocordyceps sobolifera biomass and characterized via a combination of chemical and spectral analyses. Employing high-performance gel permeation chromatography (HPGPC), the average molecular weight is proven to be 7.4 × 104 Da. Furthermore, a sugar composition analysis of the obtained polysaccharide suggests two main sugars, ß-d-glucose and α-d-mannose, at a molar ratio of 2:1, respectively, in the backbone. The structure analysis unveils that PS-T80 is a mannoglucan, possessing the repeating unit of [→3)-ß-d-Glcp-(1 → 3)-α-d-Manp-(1 → 3)-ß-d-Glcp-(1→] n . Such a configuration could be considered a novel polysaccharide. Impressively, in vitro antioxidant tests revealed that PS-T80 has a promising antioxidant activity. These results demonstrate that the obtained PS is a potential bioactive material for biomedical applications.

Graphitic carbon nitride based immobilized and non-immobilized floating photocatalysts for environmental remediation.

In solar photocatalysis, light utilization and recycling of powder from reaction solution are the main obstructions that hinder the photocatalytic efficacy of any photocatalyst. In this respect, a floatable system is effective for efficient solar photocatalysis by light utilization. Due to the maximum solar light absorption property, floating nanocomposite photocatalyst is an appealing substitute for effective wastewater treatment. Floating photocatalysts are a non-oxygenated and non-stirred solution that is a good light harvester, stable, non-toxic, biodegradable, naturally abundant in nature. They also have low density, a simple preparation process, no need to stir, and high porosity. Due to these characteristics, floating photocatalysts are widely favored and ideal candidates for practical environmental remediation. Several researchers have come up with new and innovative ways for immobilizing capable photocatalyst on a floatable substrate to produce floating nanocomposite photocatalytic material. In recent decades, g-C3N4-based floating photocatalysts have gained a lot of attention as g-C3N4 is a visible light active photocatalyst with unique and exceptional properties. It also has good photocatalytic activity in waste water treatment and environmental remediation. Many previous reports have studied the logical design and manufacturing method for heterojunction floating photocatalysts and immobilized floating photocatalysts. Based on those studies, we have focused on the g-C3N4 based immobilized and non-immobilized floating photocatalysts for pollutant degradation. We have also categorized immobilized floating photocatalyst based on several lightweight substrates such as expanded perlite and glass microbead. In addition, future challenges have been discussed to maximize solar light absorption and to improve the efficiency of broadband response floating photocatalysts. Floating photocatalysis is an advanced technique in energy conversion and environmental remediation thus requires special consideration.

Rich d-Fructose-Containing Polysaccharide Isolated from Myxopyrum smilacifolium Roots toward a Superior Antioxidant Biomaterial.

The presented study attempts to unveil and evaluate the antioxidant activity of a novel heteropolysaccharide separated from the roots of Myxopyrum smilacifolium (denoted as PS-MSR). The molecular weight of PS-MSR is found to be 1.88 × 104 Da and contains two principal sugars, which are d-glucose and d-fructose, in the backbone. Decoding the structure of the obtained PS-MSR sample has disclosed a novel polysaccharide for the first time. Indeed, the PS-MSR is composed of (1 → 3)-linked glucosyl units and (2 → 3)-linked fructosyl units. In addition, the 1D and 2D NMR spectra of the PS-MSR sample display the repeating unit of the isolated polysaccharide, [→3)-α-d-Glcp-(1 → 3)-ß-d-Frucf-(2 → 3)-ß-d-Frucf-2 → 3)-)-ß-d-Frucf-ß-(2→] n . Interestingly, the PS-MSR sample exhibits outstanding antioxidant activity, signifying the potential utilization of the explored polysaccharide for antioxidant-based material.

Novel cryptomelane nanosheets for the superior catalytic combustion of oxygenated volatile organic compounds.

This work offers a novel pathway to prepare cryptomelane manganese oxides nanosheets as an superior catalyst for the catalytic combustion of oxygenated volatile organic compounds. The tunnel cryptomelane manganese oxides nanosheets were prepared from layered birnessite via simultaneously tuning pH and molar ratio (ROK) of the redox-precipitation between oxalic acid and KMnO4. Thus, few-layered cryptomelane nanosheets possessing the most predominantly exposed (211) facet are generated at low pH (5.2-5.6), which intensifies the surface area of thin crystal cryptomelane nanosheets up to 177 m2g-1 and weakens Mn-O bonds. Moreover, high ROK results in low manganese average oxidation state (AOS), greater oxygen vacancies and better low-temperature reduction and oxygen mobility. Such features significantly maneuver the catalytic activity of the cryptomelane nanosheets catalysts for the complete oxidation of oxygenated volatile organic compound (e.g., 2-propanol, acetone) at low temperature (170-230 °C). Moreover, the catalysts show high stability for 48 h. The presented catalyst discloses an avenue to address current obstacles in the catalytic oxidation of volatile organic compounds.

Recent Progress in Carbon Nanotube Polymer Composites in Tissue Engineering and Regeneration.

Scaffolds are important to tissue regeneration and engineering because they can sustain the continuous release of various cell types and provide a location where new bone-forming cells can attach and propagate. Scaffolds produced from diverse processes have been studied and analyzed in recent decades. They are structurally efficient for improving cell affinity and synthetic and mechanical strength. Carbon nanotubes are spongy nanoparticles with high strength and thermal inertness, and they have been used as filler particles in the manufacturing industry to increase the performance of scaffold particles. The regeneration of tissue and organs requires a significant level of spatial and temporal control over physiological processes, as well as experiments in actual environments. This has led to an upsurge in the use of nanoparticle-based tissue scaffolds with numerous cell types for contrast imaging and managing scaffold characteristics. In this review, we emphasize the usage of carbon nanotubes (CNTs) and CNT-polymer composites in tissue engineering and regenerative medicine and also summarize challenges and prospects for their potential applications in different areas.

Synergistic Effect of Fe Doping and Plasmonic Au Nanoparticles on W18O49 Nanorods for Enhancing Photoelectrochemical Nitrogen Reduction.

Photoelectrochemical (PEC) nitrogen fixation has opened up new possibilities for the production of ammonia from water and air under mild conditions, but this process is confronted by the inherent challenges associated with theoretical and experimental works, limiting the efficiency of the nitrogen reduction reaction. Herein, we report for the first time a novel and efficient photoelectrocatalytic system, which has been prepared by assembling plasmonic Au nanoparticles with Fe-doped W18O49 nanorods (denoted as WOF-Au). (i) The introduction of exotic Fe atoms into nonstoichiometric W18O49 can eliminate bulk defects of the W18O49 host, which resulted in narrowing bandgap energy and facilitating electron-hole separation and transportation. (ii) Meanwhile, Au nanoparticles combined with a semiconductor induce the localized surface plasmon resonance and generate energetic (hot) electrons, increasing electron density on W18O49 nanorods. Consequently, this plasmonic WOF-Au system shows an NH3 production yield of 9.82 µg h-1 cm-2 at -0.65 V versus Ag/AgCl, which is ∼2.5-folds higher than that of the WOF (without Au loading), as well as very high stability, and no NH3 formation was found for the bare W18O49 (WO). This high activity can be associated with the synergistic effects between the Fe dopant and plasmonic Au NPs on the host semiconductor W18O49. This work can bring some insights into the target-directed design of efficient plasmonic hybrid systems for N2 fixation and artificial photocatalysis.

Novel Exopolysaccharide Produced from Fermented Bamboo Shoot-Isolated Lactobacillus Fermentum.

This study aimed at providing a route towards the production of a novel exopolysaccharide (EPS) from fermented bamboo shoot-isolated Lactobacillus fermentum. A lactic acid bacteria strain, with high EPS production ability, was isolated from fermented bamboo shoots. This strain, R-49757, was identified in the BCCM/LMG Bacteria Collection, Ghent University, Belgium by the phenylalanyl-tRNA synthetase gene sequencing method, and it was named Lb. fermentum MC3. The molecular mass of the EPS measured via gel permeation chromatography was found to be 9.85 × 104 Da. Moreover, the monosaccharide composition in the EPS was analyzed by gas chromatography-mass spectrometry. Consequently, the EPS was discovered to be a heteropolysaccharide with the appearance of two main sugars-D-glucose and D-mannose-in the backbone. The results of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance spectroscopy analyses prove the repeating unit of this polysaccharide to be [→6)-ß-D-Glcp-(1→3)-ß-D-Manp-(1→6)-ß-D-Glcp-(1→]n, which appears to be a new EPS. The obtained results open up an avenue for the production of novel EPSs for biomedical applications.

Novel Architecture Titanium Carbide (Ti3C2Tx) MXene Cocatalysts toward Photocatalytic Hydrogen Production: A Mini-Review.

Low dimensional transition metal carbide and nitride (MXenes) have been emerging as frontier materials for energy storage and conversion. Ti3C2Tx was the first MXenes that discovered and soon become the most widely investigated among the MXenes family. Interestingly, Ti3C2Tx exhibits ultrahigh catalytic activity towards the hydrogen evolution reaction. In addition, Ti3C2Tx is electronically conductive, and its optical bandgap is tunable in the visible region, making it become one of the most promising candidates for the photocatalytic hydrogen evolution reaction (HER). In this review, we provide comprehensive strategies for the utilization of Ti3C2Tx as a catalyst for improving solar-driven HER, including surface functional groups engineering, structural modification, and cocatalyst coupling. In addition, the reaming obstacle for using these materials in a practical system is evaluated. Finally, the direction for the future development of these materials featuring high photocatalytic activity toward HER is discussed.

Synthesis of Diatomite-Based Mesoporous Wool-Ball-Like Microspheres and Their Application for Toluene Total Oxidation Reaction.

Diatomite (DE) has attracted considerable attention owing to its abundance, low cost, and potential for a wide variety of applications. This work reports the development of mesoporous wool-ball-like (WBL) microspheres from natural DE through a simple hydrothermal treatment. We discovered that the presence of cetyltrimethylammonium bromide is a prerequisite for generating monodispersed WBL microspheres. The mechanism for the transformation of pristine DE into mesoporous microspheres through dissolution-recrystallization was clearly investigated. Interestingly, the microspheres exhibited a specific surface area 25-60 times larger than that of the pristine DE. The application of WBL microsphere DE as an effective support for metallic catalysts in the toluene total oxidation reaction was demonstrated.

Decoding the Capability of Lactobacillus plantarum W1 Isolated from Soybean Whey in Producing an Exopolysaccharide.

This study aims at producing exopolysaccharides (EPS) from a lactic acid bacterial strain. The soybean whey-isolated Lactobacillus plantarum W1 (EPS-W1), which belongs to genus Lactobacillus, is identified using the phenylalanyl-tRNA sequencing method. Of all the examined strains, R-49778 (as numbered by BCCM/LMG Bacteria Collection, Ghent University, Belgium) showed the highest capability of producing exopolysaccharides. Structural characterization revealed a novel exopolysaccharide consisting of repeating units of →6)-d-Glcp-(1→; →3)-d-Manp-(1→; →3)-d-Glcp-(1→ and a branch of →6)-d-Manp-(1→; →2)-d-Glcp-(1→. This discovery opens up avenues for the production of EPS for food industries, functional foods, and biomedical applications.

Synthesis of g-C3 N4 Nanosheets by Using a Highly Condensed Lamellar Crystalline Melamine-Cyanuric Acid Supramolecular Complex for Enhanced Solar Hydrogen Generation.

A highly condensed lamellar melamine-cyanuric acid supramolecular (MCS) complex was synthesized in an autoclave at high pressure as a precursor for preparing g-C3 N4 nanosheets. Given the distinctive properties of the prepared MCS complex, an efficient g-C3 N4 nanosheet photocatalyst can be obtained by heat treatment of this MCS complex under Ar followed by calcination in air at 400 °C. The resulting nanosheets with in-plane nanoholes showed an extremely high specific surface area (≈270 m2 g-1 ) and significantly enhanced light absorption in the visible region. This phenomenon is observed for the first time in carbon nitride nanosheets. The enhanced light absorption results from the sizeable conjugated system of tri-striazine units in the carbon nitride framework, coupled with the structural defects arising from the presence of oxygen-containing groups induced during the synthesis. Consequently, the obtained carbon nitride nanosheets exhibited excellent performance for hydrogen generation under sunlight and especially under visible light. Its quantum efficiency (QE) of 20.9 % at 420 nm is one of the highest reported values for carbon nitride materials. A QE of 3.5 % could be observed even at 590 nm. The integrated QE of this material in the visible region (420-600 nm) is approximately 1 %. To the best of our knowledge this is the highest value compared to all other the carbon nitride nanosheet materials reported previously.

Materials and Mechanisms of Photo-Assisted Chemical Reactions under Light and Dark Conditions: Can†Day-Night Photocatalysis Be Achieved?

The photoassisted catalytic reaction, conventionally known as photocatalysis, is expanding into the field of energy and environmental applications. It is widely known that the discovery of TiO2 -assisted photochemical reactions has led to several unique applications, such as degradation of pollutants in water and air, hydrogen production through water splitting, fuel conversion, cancer treatment, antibacterial activity, self-cleaning glasses, and concrete. These multifaceted applications of this phenomenon can be enriched and expanded further if this process is equipped with more tools and functions. The term "photoassisted" catalytic reactions clearly emphasizes that photons are required to activate the catalyst; this can be transcended even into the dark if electrons are stored in the material for the later use to continue the catalytic reactions in the absence of light. This can be achieved by equipping the photocatalyst with an electron-storage material to overcome current limitations in photoassisted catalytic reactions. In this context, this article sheds lights on the materials and mechanisms of photocatalytic reactions under light and dark conditions. The manifestation of such systems could be an unparalleled technology in the near future that could influence all spheres of the catalytic sciences.

Ni supported CdIn2S4 spongy-like spheres: a noble metal free high-performance sunlight driven photocatalyst for hydrogen production.

Nickel supported CdIn2S4 (Ni-CIS) spongy-like spheres have been developed using alcoholysis followed by a sulfidation process. The formation of nanocrystalline-single phase CdIn2S4 was confirmed using X-ray diffraction studies. Electron microscopy images showed that the spongy-like spheres are composed of CdIn2S4 nanoparticles with average sizes of around 25 nm. X-ray photoelectron spectra indicated the presence of elements with their respective stable oxidation states that led to the formation of single phase CdIn2S4 with enhanced structural integrity and chemical composition. The absorption spectra indicated the visible light activity of the material and the band gap energy is deduced to be 2.23 eV. The photocatalytic efficiency of the synthesized Ni-CIS in relation to its ability to produce hydrogen under solar light irradiation is estimated to be 1060 µmol g-1 h-1, which is around 5.5 and 3.6 fold higher than that of Pt-CIS (180 µmol g-1 h-1) and Pd-CIS (290 µmol g-1 h-1), respectively, as obtained in this study. Accordingly, the mechanism of the observed efficiency of the Ni-CIS nanoparticles is also proposed. The recyclability test showed consistent hydrogen evolution efficiency over 3 cycles (9 h), which essentially revealed the excellent photo- and chemical-stability of the photocatalyst. The strategy to utilize non-noble metals such as Ni, rather than noble-metals, as a co-catalyst opens up a new possibility to develop low cost and high-performance sunlight-driven photocatalysts as achieved in this study.