An X-ray analysis of exfoliated MoS2, produced by means of microwave-assisted liquid-phase exfoliation (LPE) from bulk powder in 1-methyl-2-pyrrolidone (NMP) or acetonitrile (ACN) + 1-methyl-2-pyrrolidone (NMP) solvents, has revealed distinct structural differences between the bulk powder and the microwave-exfoliated samples. Specifically, we performed X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements to identify the elements of our exfoliated sample deposited on a Si substrate by drop-casting, as well as their chemical state and its structural crystalline phase. In the exfoliated sample, the peaks pattern only partially resemble the theoretical Miller indices for MoS2. In contrast, the bulk powder\'s spectrum shows the characteristic peaks of the 2H polytype of MoS2, but with some broadening. Notable is the retention of partial crystallinity in the post-exfoliation phases, specifically in the normal-to-plane orientation, thus demonstrating the effectiveness of microwave-assisted techniques in producing 2D MoS2 and attaining desirable properties for the material. XPS measurements confirm the success of the exfoliation procedure and that the exfoliated sample retains its original structure. The exfoliation process has been optimized to maintain the structural integrity of MoS2 while enhancing its surface area and electrochemical performance, thereby making it a promising material for advanced electronic and optoelectronic applications ranging from energy storage to sensing devices under ambient conditions.

Microwaves have become an essential part of the modern kitchen, but their potential as a reservoir for bacterial colonization and the microbial composition within them remain largely unexplored. In this study, we investigated the bacterial communities in microwave ovens and compared the microbial composition of domestic microwaves, microwaves used in shared large spaces, and laboratory microwaves, using next-generation sequencing and culturing techniques. The microwave oven bacterial population was dominated by Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes, similar to the bacterial composition of human skin. Comparison with other environments revealed that the bacterial composition of domestic microwaves was similar to that of kitchen surfaces, whereas laboratory microwaves had a higher abundance of taxa known for their ability to withstand microwave radiation, high temperatures and desiccation. These results suggest that different selective pressures, such as human contact, nutrient availability and radiation levels, may explain the differences observed between domestic and laboratory microwaves. Overall, this study provides valuable insights into microwave ovens bacterial communities and their potential biotechnological applications.

As one of the crucial components of the food system, starch can be hydrolyzed into glucose after gastrointestinal digestion, so regulating its digestive properties is vital for maintaining health. Microwaves can promote the rearrangement of intramolecular structure of starch, thus improving its physicochemical properties, enhancing its slowly digestible features, and expanding its scope of application. This review zooms in describing recent research results concerning the effects of microwave treatment on the multi-scale structure and physicochemical properties of starch and summarizing the patterns of these changes. Furthermore, the changes in starch structure, resistant starch content, and glycemic index after digestion are pointed out to gain an insight into the enhancement of starch slowly digestible properties by microwave treatment. The resistance of starch to enzymatic digestion may largely hinge on the specific structures formed during microwave treatment. The multi-level structural evolutions of starch during digestion endow it with the power to resist digestion and lower the glycemic index. The properties of starch dictate its application, and these properties are highly associated with its structure. Consequently, understanding the structural changes of microwave-modified starch helps to prepare modified starch with diversified varieties and functional composites.

Microwave gas sensors have garnered attention for their high sensitivity and selectivity in the detection of volatile organic compounds (VOCs). However, traditional gas sensors generally rely on sensitive materials that degrade over time and are easily affected by the environment, compromising their stability and accuracy. This study proposes a microwave VOC gas sensor based on the condensation effect. The sensor adopts a novel design without sensitive materials, utilizing the condensation effect to detect acetone gas. The sensor system consists of a microwave sensor and a temperature control device. As the sensor temperature is lowered below the boiling point of acetone, the condensation of acetone gas on the sensor surface is achieved, enabling accurate detection of acetone gas. Experimental results indicate that the accumulated amount of acetone on the sensor surface is positively correlated with its response, with the maximum response of 3000 ppm acetone gas reaching 0.34 dB. Additionally, this study investigated the detection mechanism of the sensor after adding the sensitive material MXene and compared the performance of the sensor at different temperatures (-10 °C, 0 °C, and 60 °C). The results show that at -10 °C the sensor mainly captures acetone through physical adsorption, while at 25 and 60 °C, it primarily responds through chemical adsorption, with a maximum response of 0.29 dB. The VOC sensor based on the condensation effect without sensitive materials not only achieves the same sensitivity as traditional microwave sensors but also demonstrates stronger stability and anti-interference capabilities.

There are many different applications of heterocyclic molecules in the pharmaceutical and materials science fields, which make them an important family of compounds. Among these heterocyclic compounds, nitrogen-containing heterocyclic (N-heterocyclic) compounds have attracted a lot of interest among researchers due to their various applications across a wide variety of fields. Many studies have been performed over the past few years to study the synthesis of N-heterocycles under different reaction conditions, such as solvent-free, catalytic, reactants immobilized on a solid support, one-pot synthesis, and microwave irradiation. It has been demonstrated by our research group that microwaves can be utilized for rapid and efficient synthesis of biologically active compounds. In this review, we provide an overview of the microwave-assisted non-catalytic and catalytic preparation of nitrogen-containing heterocycles, mostly polycyclic N-heterocycles, five-membered N-heterocycles, six-membered N-heterocycles, and fused N-heterocycles. Mostly in this article, we explore the microwave-assisted preparation of biologically important compounds, such as pyrimidines, thiazoles, imines, tetrazoles, steroidal derivatives, quinolines, indolizine, triazoles, beta-lactams, pyrroles and quinoxalines.

Microalgae are increasingly recognized as promising sources of natural bioactive compounds. However, traditional extraction methods using volatile organic solvents (VOCs) pose environmental risks. This study explores renewable deep eutectic solvents (DES) as sustainable alternatives for extracting bioactive compounds from microalgae biomass, focusing on Chlorella vulgaris and Scenedesmus incrassatulus. Four DES systems, comprising choline chloride (ChCl) and glycerol, citric acid, urea, and glucose, were compared with three conventional solvents (ethanol, methanol, and water). Extraction efficiency was assessed based on total phenolic content (TPC), flavonoid content, and tannin content, followed by antioxidant activity evaluation using DPPH, CAT, and FRAP assays. Additionally, antibacterial activity of the DES extracts was determined against Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 29213), and Bacillus subtilis (ATCC 3366) using disc diffusion and microplate dilution methods to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results reveal that DES, particularly choline chloride: citric acid, outperform conventional solvents in terms of polyphenol extraction efficiency, antioxidant activity, and antibacterial activity against both Gram-negative and Gram-positive bacteria. For instance, the citric acid-based DES (SIDES2) showed a TPC of 4.98 mg/g, while the conventional solvent ethanol exhibited a TPC of 3.27 mg/g. Additionally, SIDES2 exhibiting the highest DPPH scavenging activity of 75 %, compared to 60 % for ethanol. Furthermore, SIDES2 showed an MIC of 0.5 mg/ml against Staphylococcus aureus. This study underscores the potential of DES for sustainable extraction of natural antioxidants from microalgae biomass, contributing to the development of environmentally friendly extraction processes in various industries.

Objectives: In this work we demonstrate the first laboratory study results of lens fragmentation with low-energy picosecond ultrashort laser pulses after artificial induction of cataract with microwave radiation on an ex vivo animal model. Background: This method will be evaluated with regard to the further development of lens fragmentation with novel ultrashort picosecond laser systems instead of ultrasonic phacoemulsification or the significantly more complex femtosecond laser fragmentation. Methods: As samples we used postmortem porcine eyes. The lenses were dissected and then irradiated in a microwave oven for artificial cataract induction. Subsequent computer-driven lens fragmentation was performed with a 12 ps, 1064 nm pulsed laser source with 100 µJ pulse energy, and 10 kHz pulse repetition rate. Results: Both the artificial cataract induction and the lens fragmentation were demonstrated. When inducing cataract, different degrees/stages of opaqueness and hardness could be achieved with different irradiation times and methods. The fragmentation with 12 ps pulses led to good results with regard to ablation depth and rate, especially for the softer lenses. Conclusions: As could be shown, low-energy picosecond ultrashort laser pulses are feasible for cataractous lens fragmentation on an ex vivo animal model with artificial cataract induction. Thus, this technique may influence future cataract surgeries by possibly being an alternative or extension to state-of-the-art methods. This will be evaluated with further tests and studies.

Herein, a microwave promoted tandem reaction of free primary arylamines with diazo compounds in water for clean synthesis of 2,2-disubstituted 3-oxindoles is present. Water plays important roles in the whole cascade process: O-H insertion to diazo, air oxidation, ortho C-H functionalization, cyclization and 1,2-ester migration. In particular, water plays a mediation role in the site selective ortho-C-H addition.

New vinegar needs a long maturing time to improve its poor flavor before sale, which greatly increases its production cost. Therefore, it is urgent to explore regulation technologies to accelerate vinegar flavor maturation. Based on literature and our research, this review introduces the latest advances in flavor regulation technologies of vinegar including microbial fortification/multi starters fermentation, key production processes optimization and novel physical processing technologies. Microbial fortification or multi starters fermentation accelerates vinegar flavor maturation via enhancing total acids, esters and aroma precursors content in vinegar. Adjusting raw materials composition, fermentation temperature, and oxygen flow reasonably increase alcohols, organic acids, polyphenols and esters levels via generating more corresponding precursors in vinegar, thereby improving its flavor. Furthermore, novel processing technologies greatly promote conversion of alcohols into acids and esters in vinegar, shortening flavor maturation time for over six months. Meanwhile, the corresponding mechanisms are discussed and future research directions are addressed.

Two microwave (MW) responsive heterojunction nanocomposite catalysts, i.e., α-Bi2O3/CoFe2O4 (BO/CFO) and ZnO/CoFe2O4 (ZO/CFO), with weight% ratio of 70/30, 50/50, 30/70 were synthesized by sequential thermal decomposition and co-precipitation methods, and used for the degradation of tetracycline (TC) under MW irradiation. The formation of desired catalysts was confirmed through the characterization results of XRD, FT-IR, SEM, VSM, UV-DRS, XPS, BET, etc. Using batch MW experiments, the catalyst dose, pH, initial TC concentration, reaction temperature, and MW power were optimized for TC removal. Under the following reaction conditions: catalyst dose ∼1 g/L, initial TC concentration ∼1 mg/L, temperature ∼90 °C, MW ∼450 W, BO/CFO, and ZO/CFO showed ∼97.55% and 88.23% TC degradation, respectively, after 5 min. The difference in the catalytic response against TC degradation indicated the difference in reflective loss (RL) between these two catalysts. The presence of other competitive anions has affected the removal efficiency of TC due to the scavenging effect. The radical trapping study revealed the significant contribution of TC degradation by hydroxyl radicals in the case of ZO/CFO, whereas for BO/CFO, superoxide (●O2-) and hydroxyl radicals (●OH) both played influential roles. The Z-scheme heterojunction of BO/CFO allowed the formation of ●O2- but the same was inhibited in type-II heterojunction of ZO/CFO due to the valance band position. The dielectric loss, magnetic loss, interfacial polarization, and high electrical conductivity, \'hotspots\' were produced over the catalyst surface alongside electron-hole separation at heterojunctions, which were responsible for the generation of reactive oxygen species. In addition, Co3+/Co2+ and Fe3+/Fe2+ redox cycles have promoted ●O2- and sulfate radical production during persulfate application. Among the two MW responsive catalysts, BO/CFO could be a potential material for rapidly destroying emerging organic pollutants from wastewater without applying other oxidative chemicals under MW irradiation.