Search Results (2,651)

In order to investigate the most extreme conditions in which materials potentially applicable in reusable thermal shields can be operated, ultra-high-temperature ZrB₂ ceramics with 20 vol.% MoSi₂ were prepared using two different techniques, cold isostatic pressing (CIP) and robocasting (RC, an additive manufacturing technique), followed by consolidation using pressureless spark plasma sintering (SPS). The oxidation behavior of the resulting materials was analyzed in low-pressure dissociated air at three different temperatures, namely 1800, 2000 and 2200 K. Using XRD and surface and cross-section SEM (coupled with EDS), zirconia was found to form at all three temperatures, while silica was only present at 1800 K, with gaseous SiO forming at a higher temperature. The elaboration technique influences the density of the ceramic, and less dense materials undergo deeper oxidation. This investigation suggests that 2000 K is already beyond the maximum temperature threshold at which damage to ceramics is limited by the formation of protective silica. This study confirms that the selected material is a promising candidate for thermal protection applications. Full article

Systems for reusing packaging (e.g., refillable bottles for laundry detergent) have the potential to reduce plastic waste and lower the environmental impact of delivering products to consumers. However, despite the potential of reusable packaging, uptake of reuse systems is typically low and so the present research investigated whether informing consumers about these benefits increases their willingness to engage with reuse systems. A total of 969 participants were asked to imagine buying consumer products, such as laundry detergent in refillable bottles, and were then randomly allocated to either receive information on the potential environmental benefit of (i) their using the scheme, (ii) the scheme as a whole, or (iii) no information. The findings suggested that the information increased consumers’ awareness of the environmental impact of reuse systems but did not increase their willingness to use such systems. This finding underscores the need for strategies that go beyond mere dissemination of information, to circumvent obstacles that prevent willing consumers from enacting desirable behaviours. Full article

The reduction of CO₂ is an important method to produce chemicals such as methanol, formic acid, formaldehyde, etc. In general, the reduction of CO₂ is carried out at high temperatures and pressures with precious metals as catalysts, which is not favorable for industrial procedures. Thus, it will be very useful if researchers can find cost-effective catalysts for industrial application in CO₂ reduction. In this work, commercially available ethylenediaminetetraacetic acid (EDTA) was tested as a cheap, non-toxic, and recyclable catalyst to initiate the N-carbonylation reaction of CO₂ with amines. After screening various reaction parameters, including temperature, pressure, time, solvent, and reducing agent, the optimal reaction conditions were obtained: 80 °C, 2 MPa, 6 h, 50 mmol% catalyst dosage, 1 mL DMSO, and 1:1 molar ratio of amine to reducing agent. Notably, further studies confirmed that EDTA could also be effective for N-formylation even under ambient conditions (0.1 MPa and room temperature). The suitability of the catalyst for 26 kinds of substrates (including aliphatic amines, aromatic amines, and alicyclic amines) and its reusability were also investigated, with satisfactory results. Scale-up research has been performed effectively with a high conversion of amine (83%) to obtain the mono-formylated product selectively. Finally, the mechanism of the reaction between amine and CO₂ has been proposed via control experiments and compared with results in the literature. Full article

Adeno-associated viruses (AAVs) have emerged as promising tools for gene therapy due to their safety and efficacy in delivering therapeutic genes or gene editing sequences to various tissues and organs. AAV serotype 9 (AAV9), among AAV serotypes, stands out for its ability to efficiently target multiple tissues, thus holding significant potential for clinical applications. However, existing methods for purifying AAVs are cumbersome, expensive, and often yield inconsistent results. In this study, we explore a novel purification strategy utilizing Dynabeads™ CaptureSelect™ magnetic beads. The AAV9 magnetic beads capture AAV9 with high specificity and recovery between 70 and 90%, whereas the AAVX magnetic beads did not bind to the AAV9. Through continuous interaction with AAVs in solution, these beads offer enhanced clearance of genomic DNA and plasmids even in the absence of endonuclease. The beads could be regenerated at least eight times, and the used beads could be stored for up to six months and reused without a significant reduction in recovery. The potency of the AAV9-purified vectors in vivo was comparable to that of iodixanol purified vectors. Full article

Green synthesis using L-proline as an organocatalyst is crucial due to its reusability, mild conditions, clean reactions, easy workup, high purity, short reaction times, and high yields. However, existing methods often involve harsh conditions and longer reaction times. In this study, 2-cyano-N’-(2-cyanoacetyl)acetohydrazide (3) was prepared and condensed with various benzaldehyde derivatives to yield 2-cyano-N’-(2-cyano-3-phenylacryloyl)-3-phenylacrylohydrazide derivatives (5a–e, 7a,b) using a grinding technique with moist L-proline. Additionally, three 2-cyano-N’-(2-cyano-3-heterylbut-2-enoyl)-3-heterylbut-2-enehydrazides (9, 11, 13) were synthesized by condensing compound 3 with respective (heteraryl)ketones (8, 10, 12) following the same method. The synthesized compounds were characterized using IR, NMR, and MS spectroscopy. L-proline’s reusability was confirmed for up to four cycles without significant yield loss, showcasing the protocol’s efficiency and sustainability. The new compounds were screened for anticancer activities against the HCT-116 colon carcinoma cell line using the MTT assay. Molecular docking studies revealed the binding conformations of the most potent compounds to the target protein (PDB ID 6MTU), correlating well with in vitro results. In silico ADMET analysis indicated favorable pharmacokinetic properties, highlighting these novel compounds as promising targeted anti-colon cancer agents. Full article

The study focuses on harnessing recycled materials to create sustainable and efficient composites, addressing both environmental issues related to waste management and industrial requirements for materials with improved vibration damping properties. The research involves the analysis of the physico-mechanical properties of the obtained composites and the evaluation of their performance in practical applications. Composite materials were tested in terms of their tensile strength and vibration damping capabilities, considering stress–strain diagrams, vibration amplitudes, frequency response functions (FRFs) and vibration modes. The research results have shown that by adding PVC and FA to the rubber-based matrix composition, the stiffness decreases and elasticity increases. The use of FA in the structure of composite materials causes an increase in the vibration damping possibilities due to the fact that it contributes to the chemical properties of the analyzed composite materials. Additionally, the use of PVC results in increased material elasticity, as evidenced by the higher damping factor compared to materials containing only rubber. Simultaneously, the addition of FA and PVC in specific proportions (60 phr) can lead to a decrease in stiffness and a greater increase in the damping factor. The incorporation of PVC and fly ash (FA) particles into rubber-based matrix composites reduces their stiffness and increases their elasticity. These effects are due to the fact that FA particles behave as extensions of chemical bonds during traction, which contributes to the increase in yield elongation. In addition, the use of flexible PVC increases the elasticity of the material, which is evidenced by the increase in the damping factor. Full article

In this paper, a new method involving a wear-resistant and reusable template is proposed for the preparation of high-mechanical-strength superhydrophobic polymer film based on wire electrical discharge machining (WEDM). A solid−liquid-contact-angle simulation model was established to obtain surface-texture types and sizes that may achieve superhydrophobicity. The experimental results from template preparation show that there is good agreement between the simulation and experimental results for the contact angle. The maximum contact angle on the template can reach 155.3° given the appropriate triangular surface texture and WEDM rough machining. Besides, the prepared superhydrophobic template exhibits good wear resistance and reusability. PDMS superhydrophobic polymer films were prepared by the template method, and their properties were tested. The experimental results from the preparation of superhydrophobic polymer films show that the maximum contact angle of the polymer films can be up to 154.8° and that these films have good self-cleaning and anti-icing properties, wear resistance, bending resistance, and ductility. Full article

Flexible manufacturing cells provide significant advantages in low-volume mass-customization production but also induce added complexity and technical challenges in terms of integration, control, and extensibility. The variety of closed-source industrial protocols, the heterogeneous equipment, and the product’s manufacturing specifications are main points of consideration in the development of such a system. This study aims to describe the approach, from concept to implementation, for the development of the controller for a flexible manufacturing cell consisting of heterogeneous equipment in terms of functions and communication interfaces. Emphasis is put on the considerations and challenges for effective integration, extensibility, and interoperability. Scheduling and monitoring performed by the developed controller are demonstrated for a manufacturing cell producing microfluidic devices (bioMEMS) that consists of six workstations and a robot-based handling system. Communication between the system controller and the workstations was based on open-source technologies instead of proprietary software and protocols, to support interoperability and, to a considerable extent, code reusability. Full article

This study explores the potential of MoS₂ monolayers as heavy metal sensors for As, Cd, Hg, and Pb using density functional theory (DFT) and Non-Equilibrium Green’s Function (NEGF) simulations. Our findings reveal that As and Pb adsorption significantly alters the surface structure and electronic properties of MoS₂, introducing impurity levels and reducing the band gap. Conversely, Cd and Hg exhibit weaker interactions with the MoS₂ surface. The MoS₂ monolayer sensors demonstrate exceptional sensitivity for all four target heavy metals, with values reaching 126,452.28% for As, 1862.67% for Cd, 427.71% for Hg, and 83,438.90% for Pb. Additionally, the sensors demonstrate selectivity for As and Pb through distinct response peaks at specific bias voltages. As and Pb adsorption also induces magnetism in the MoS₂ system, potentially enabling magnetic sensing applications. The MoS₂ monolayer’s moderate adsorption energy facilitates rapid sensor recovery at room temperature for As, Hg, and Cd. Notably, Pb recovery time can be significantly reduced at elevated temperatures, highlighting the reusability of the sensor. These results underscore the potential of MoS₂ monolayers as highly sensitive, selective, and regenerable sensors for real-time heavy metal detection. Full article

Timely and accurate detection of viruses is crucial for infection diagnosis and treatment. However, it remains a challenge to develop a portable device that meets the requirement of being portable, powerless, user-friendly, reusable, and low-cost. This work reports a compact ∅30 × 48 mm portable powerless isothermal amplification detection device (material cost ∼$1 USD) relying on LAMP (Loop-Mediated Isothermal Amplification). We have proposed chromatographic-strip-based microporous permeation technology which can precisely control the water flow rate to regulate the exothermic reaction. This powerless heating combined with phase-change materials can maintain a constant temperature between 50 and 70 °C for a duration of up to 49.8 min. Compared with the conventional methods, it avoids the use of an additional insulation layer for heat preservation, greatly reducing the size and cost. We have also deployed a color card and a corresponding algorithm to facilitate color recognition, data analysis, and storage using a mobile phone. The experimental results demonstrate that our device exhibits the same limit of detection (LOD) as the ProFlex PCR for SARS-CoV-2 pseudovirus samples, with that for both being ${10}^3$ copies/μL, verifying its effectiveness and reliability. This work offers a timely, low-cost, and easy way for respiratory infectious disease detection, which could provide support in curbing virus transmission and protecting the health of humans and animals, especially in remote mountainous areas without access to electricity or trained professionals. Full article

Covalent cross-linked hydrogels based on chitosan and poly(maleic acid-alt-vinyl acetate) were prepared as spherical beads. The structural modifications of the beads during the preparation steps (dropping in liquid nitrogen and lyophilization, thermal treatment, washing with water, and treatment with NaOH) were monitored by FT-IR spectroscopy. The hydrogel beads have a porous inner structure, as shown by SEM microscopy; moreover, they are stable in acidic and basic pH due to the covalent crosslinking. The swelling degree is strongly influenced by the pH since the beads possess ionizable amine and carboxylic groups. The binding capacity for Cu²⁺ ions was examined in batch mode as a function of sorbent composition, pH, contact time, and the initial concentration of Cu²⁺. The kinetic data were well-fitted with the pseudo-second-order kinetic, while the sorption equilibrium data were better fitted with Langmuir and Sips isotherms. The maximum equilibrium sorption capacity was higher for the beads obtained with a 3:1 molar ratio between the maleic copolymer and chitosan (142.4 mg Cu²⁺ g⁻¹), compared with the beads obtained using a 1:1 molar ratio (103.7 mg Cu²⁺ g⁻¹). The beads show a high degree of reusability since no notable decrease in the sorption capacity was observed after five consecutive sorption/desorption cycles. Full article

The energy sector is the sector that generates the highest amount of environmental contamination, especially in water sources, mostly in the case of coal-based energy production. The aim of this study was to examine a significant contamination source, heavy metal contamination, in coal mining effluents. The current investigation introduces an MOF platform based on zirconium clusters and isophthalic acid with NH₂-MIP-SO₃H mixed amine and sulfonic acid functional groups in order to remove the most common heavy metal ions in coal mining effluents, including Hg, Cd, Pb, and Cu ions. The water matrix and the operational conditions were identified to be very influential in the removal process, such as the pH of water, the initial metal concentration and operating time. NH₂-MIP-SO₃H offers a great removal efficiency of metals starting from 745.83 mg/g for Cd, 673.67 mg/g for Cu, 589.85 mg/g for Hg, and 481.66 mg/g for Pb ions, with the Langmuir equation for equilibrium and pseudo-second-order equation for kinetics being the ideal models to express the equilibrium and kinetic data, respectively. A significant impact of water pH was found to occur, with the NH₂-MIP-SO₃H platform performing best at pH 6. Reuse of NH₂-MIP-SO₃H demonstrates excellent reusability, sustaining 90% of initial performance over eight regeneration cycles. The interaction of functional group-functional metal was the dominant mechanism in the removal process. The NH₂-MIP-SO₃H unique approach to heavy metal removal provides a very hopeful outlook for additional investigations in larger-scale studies. Full article

With the rapid development of modern industry, it is urgently needed to measure the biotoxicity of complex chemicals. Microbial electrochemical biotoxicity sensors are an attractive technology; however, their application is usually limited by their stability and reusability after measurements. Here, we improve their performance by encapsulating the electroactive biofilm with polydopamine (PDA), and we evaluate the improvement by different concentrations of heavy metal ions (Cu²⁺, Ag⁺, and Fe³⁺) in terms of inhibition ratio (IR) and durability. Results indicate that the PDA-encapsulated sensor exhibits a more significant detection concentration than the control group, with a 3-fold increase for Cu²⁺ and a 1.5-fold increase for Ag⁺. Moreover, it achieves 15 more continuous toxicity tests than the control group, maintaining high electrochemical activity even after continuous toxicity impacts. Images from a confocal laser scanning microscope reveal that the PDA encapsulation protects the activity of the electroactive biofilm. The study, thus, demonstrates that PDA encapsulation is efficacious in improving the performance of microbial electrochemical biotoxicity sensors, which can extend its application to more complex media. Full article

Photocatalytic methods have been popular in energy production and environmental remediation. Designing high-efficiency photocatalysts is still challenging in converting solar energy into chemical fuels. Herein, a series of surfactant-assisted ZnIn₂S₄ (ZIS) photocatalysts were synthesized by utilizing the one-pot hydrothermal method. Photocatalytic methane production from an acetic acid solution was carried out under LED light (450 nm) irradiation, and the evolved gas was analyzed by the GC-FID system. Reaction factors (surfactant amount, catalyst dose, reaction temperature, substrate concentration, and reaction pH) were optimized for photocatalytic production. With the increase in cetyltrimethylammonium bromide (CTAB) amount, CH₄ production gradually increased. The ZIS-3.75 photocatalyst exhibited the highest photocatalytic CH₄ production rate (0.102 µmol g⁻¹·h⁻¹), which was approximately 1.8 times better than that of pure ZIS (0.058 µmol g⁻¹·h⁻¹). The presence of CTAB reduced the charge transfer resistance and improved photocurrent response efficiency. Structure and morphology were characterized by XRD, FTIR, SEM, TEM, and N₂ adsorption–desorption isotherm analysis. Optical properties were investigated by UV-DRS and PL spectroscopic techniques. The electrochemical evaluation was measured through EIS, Mott–Schottky, and transient photocurrent response analysis. The CTAB-modified catalyst showed excellent stability and reusability, even after five irradiation cycles. Methane production was enhanced by lowering the photogenerated charge transfer resistance and boosting the dispersion of ZIS-3.75 under visible light (450 nm) irradiation. Full article

Developing reusable and easy-to-operate biocatalysts is of significant interest in biodiesel production. Here, magnetic whole-cell catalysts constructed through immobilizing recombinant Escherichia coli cells (containing MAS1 lipase) into Fe₃O₄–chitosan magnetic microspheres (termed MWCC@MAS1) were used for fatty acid methyl ester (FAME) production from waste cooking oil (WCO). During the preparation process of immobilized cells, the effects of chitosan concentration and cell concentration on their activity and activity recovery were investigated. Optimal immobilization was achieved with 3% (w/v) chitosan solution and 10 mg wet cell/mL cell suspension. Magnetic immobilization endowed the whole-cell catalysts with superparamagnetism and improved their methanol tolerance, enhancing the recyclability of the biocatalysts. Additionally, we studied the effects of catalyst loading, water content, methanol content, and reaction temperature on FAME yield, optimizing these parameters using response surface methodology and Box–Behnken design. An experimental FAME yield of 89.19% was gained under the optimized conditions (3.9 wt% catalyst loading, 22.3% (v/w) water content, 23.0% (v/w) methanol content, and 32 °C) for 48 h. MWCC@MAS1 demonstrated superior recyclability compared to its whole-cell form, maintaining about 86% of its initial productivity after 10 cycles, whereas the whole-cell form lost nearly half after just five cycles. These results suggest that MWCC@MAS1 has great potential for the industrial production of biodiesel. Full article