Search Results (6,093)

This research is concerned with design optimization of control systems. Our case study deals with magnetic levitation, in which an essential part is a solenoid. Its dimensions, along with controller parameters, form the optimization variables. We present a novel way of writing the explicit expression of the solenoid’s force acting on a magnetic dipole, as well as its first derivatives. Numerical tests using non-gradient search algorithms show the difference in optimal designs provided by these methods. Since such optimization depends on output signals, a comparison of step response analysis methods is presented. Full article

Traditional hydrogel preparation methods typically require multiple steps and certain external stimuli. In this study, rapid and stable gelation of polyvinyl alcohol (PVA)-tannic acid (TA)-based hydrogels was achieved through the regulation of hydrogen bonds. The cross-linking between PVA and TA is triggered by the evaporation of ethanol. Rheological testing and analysis of the liquid-solid transformation process of the hydrogel were performed. The gelation onset time (GOT) could be tuned from 10 s to over 100 s by adjusting the ethanol content and temperature. The addition of polyhydroxyl components (e.g., glycerol) significantly enhances the hydrogel’s water retention capacity (by 858%) and tensile strain rate (by 723%), while concurrently increasing the gelation time. Further studies have shown that the addition of alkaline substances (such as sodium hydroxide) promotes the entanglement of PVA molecular chains, increasing the tensile strength by 23% and the fracture strain by 41.8%. The experimental results indicate that the optimized PVA-TA hydrogels exhibit a high tensile strength (>2 MPa) and excellent tensile properties (~600%). Moreover, the addition of an excess of weakly alkaline substances (such as sodium acetate) reduces the degree of hydrolysis of PVA, enabling the system to form a hydrogel with extrudable characteristics before the ethanol has completely evaporated. This property allows for patterned printing and thus demonstrates the potential of the hydrogel in 3D printing. Overall, this study provides new insights for the application of PVA-TA based hydrogels in the fields of rapid prototyping and strength optimization. Full article

As an efficient clean energy technology, water electrolysis for hydrogen production has its efficiency limited by the sluggish oxygen evolution reaction (OER) kinetics, which drives the demand for the development of high-performance anode OER catalysts. This work constructs bimetallic (Al, Mn) co-doped nanoporous spinel CoFe₂O₄ (np-CFO) with a tunable structure and composition as an OER catalyst through a simple two-step dealloying strategy. The as-formed np-CFO (Al and Mn) features a hierarchical flaky configuration; that is, there are a large number of fine nanosheets attached to the surface of a regular micron-sized flake, which not only increases the number of active sites but also enhances mass transport efficiency. Consequently, the optimized catalyst exhibits a low OER overpotential of only 320 mV at a current density of 10 mA cm⁻², a minimal Tafel slope of 45.09 mV dec⁻¹, and exceptional durability. Even under industrial conditions (6 M KOH, 60 °C), it only needs 1.83 V to achieve a current density of 500 mA cm⁻² and can maintain good stability for approximately 100 h at this high current density. Theoretical simulations indicate that Al and Mn co-doping could indeed optimize the electronic structure of CFO and thus decrease the energy barrier of OER to 1.35 eV. This work offers a practical approach towards synthesizing efficient and stable OER catalysts. Full article

Divinylisoprene rubber, a copolymer of butadiene and isoprene, is used as raw material for rubber technical products, combining isoprene rubber’s elasticity and butadiene rubber’s wear resistance. These properties depend quantitatively on the copolymer composition, which depends on the kinetics of its synthesis. This work aims to theoretically describe how the monomer mixture composition in the butadiene–isoprene copolymerization affects the activity of the TiCl₄–Al(i-C₄H₉)₃ catalytic system (expressed by active sites concentration) via kinetic modeling. This enables development of a reliable kinetic model for divinylisoprene rubber synthesis, predicting reaction rate, molecular weight, and composition, applicable to reactor design and process intensification. Active sites concentrations were calculated from experimental copolymerization rates and known chain propagation constants for various monomer compositions. Kinetic equations for active sites formation were based on mass-action law and Langmuir monomolecular adsorption theory. An analytical equation relating active sites concentration to monomer composition was derived, analyzed, and optimized with experimental data. The results show that monomer composition’s influence on active sites concentration is well described by a two-step kinetic model (physical adsorption followed by Ti–C bond formation), accounting for competitive adsorption: isoprene adsorbs more readily, while butadiene forms more stable active sites. Full article

Stress granule formation is a type of liquid–liquid phase separation in the cytoplasm, leading to RNA–protein condensates that are associated with various cellular stress responses and implicated in numerous pathologies, including cancer, neurodegeneration, inflammation, and cellular senescence. One of the key components of mammalian stress granules is the DEAD-box RNA helicase DDX3, which unwinds RNA in an ATP-dependent manner. DDX3 is involved in multiple steps of RNA metabolism, facilitating gene transcription, splicing, and nuclear export and regulating cytoplasmic translation. In this study, we investigate the role of the RNA helicase DDX3’s enzymatic activity in shaping the RNA content of ribonucleoprotein (RNP) condensates formed during arsenite-induced stress by inhibiting DDX3 activity with RK-33, a small molecule previously shown to be effective in cancer clinical studies. Using the human osteosarcoma U2OS cell line, we purified the RNP granule fraction and performed RNA sequencing to assess changes in the RNA pool. Our results reveal that RK-33 treatment alters the composition of non-coding RNAs within the RNP granule fraction. We observed a DDX3-dependent increase in circular RNA (circRNA) content and alterations in the granule-associated intronic RNAs, suggesting a novel role for DDX3 in regulating the cytoplasmic redistribution of non-coding RNAs. Full article

Rapid screening of foodborne pathogens is critical for food safety, yet current detection techniques often suffer from low efficiency and complexity. In this study, we developed a sliding microfluidic colorimetric biosensor for the fast, sensitive, and multiplex detection of Salmonella. First, the target bacteria were specifically captured by antibody-functionalized magnetic nanoparticles in the microfluidic chip, forming magnetic bead–bacteria complexes. Then, through motor-assisted sliding of the chip, manganese dioxide (MnO₂) nanoflowers conjugated with secondary antibodies were introduced to bind the captured bacteria, generating a dual-antibody sandwich structure. Finally, a second sliding step brought the complexes into contact with a chromogenic substrate, where the MnO₂ nanoflowers catalyzed a colorimetric reaction, and the resulting signal was used to quantify the Salmonella concentration. Under optimized conditions, the biosensor achieved a detection limit of 10 CFU/mL within 20 min. In spiked pork samples, the average recovery rate of Salmonella ranged from 94.9% to 125.4%, with a coefficient of variation between 4.0% and 6.8%. By integrating mixing, separation, washing, catalysis, and detection into a single chip, this microfluidic biosensor offers a user-friendly, time-efficient, and highly sensitive platform, showing great potential for the on-site detection of foodborne pathogens. Full article

Tryptophan is synthesized in microorganisms via a five-step enzymatic pathway originating from chorismate, which is a product of the shikimate pathway. As a biosynthetic precursor to a wide range of high-value compounds such as indole-3-acetic acid, indigo, indirubin, and violacein, this pathway has been a central target for metabolic engineering to enhance microbial production. Anthranilate phosphoribosyltransferase (AnPRT) catalyzes the second step of the pathway by transferring a phosphoribosyl group from PRPP to anthranilate, forming phosphoribosyl anthranilate (PRA). AnPRT, the sole member of class IV phosphoribosyltransferases, adopts a unique fold and functions as a homodimer. While the structural basis of AnPRT activity has been elucidated in several organisms, thermostable variants remain underexplored despite their relevance for high-temperature bioprocessing. In this study, the crystal structure of AnPRT from the thermophilic archaeon Methanocaldococcus jannaschii (MjAnPRT) was determined at a 2.16 Å resolution. The enzyme exhibits a conserved dimeric architecture and key catalytic motifs. Comparative structural analysis with mesophilic and hyper thermophilic homologs revealed that MjAnPRT possesses enhanced local stability in catalytically important regions and strengthened inter-subunit interactions. These features likely contribute to its thermostability and provide a valuable framework for the rational design of robust AnPRTs for industrial and synthetic biology applications. Full article

Ribosome biogenesis is a highly coordinated, multi-step process that assembles the ribosomal machinery responsible for translating mRNAs into proteins. It begins with the rate-limiting step of RNA polymerase I (Pol I) transcription of the 47S ribosomal RNA (rRNA) genes within a specialised nucleolar region in the nucleus, followed by rRNA processing, modification, and assembly with ribosomal proteins and the 5S rRNA produced by Pol III. The ribosomal subunits are then exported to the cytoplasm to form functional ribosomes. This process is tightly regulated by the PI3K/RAS/MYC oncogenic network, which is frequently deregulated in many cancers. As a result, ribosome synthesis, mRNA translation, and protein synthesis rates are increased. Growing evidence supports the notion that dysregulation of ribosome biogenesis and mRNA translation plays a pivotal role in the pathogenesis of cancer, positioning the ribosome as a promising therapeutic target. In this review, we summarise current understanding of dysregulated ribosome biogenesis and function in cancer, evaluate the clinical development of ribosome targeting therapies, and explore emerging targets for therapeutic intervention in this rapidly evolving field. Full article

Oral delivery of hydrophobic compounds remains challenging due to their poor aqueous solubility and the potential toxicity associated with conventional surfactant-based emulsions. To address these issues, we present a surfactant-free encapsulation strategy using electrosprayed alginate hydrogel beads for the stable and controlled delivery of hydrophobic oils. Hydrophobic compounds were dispersed in high-viscosity alginate solutions without surfactants via ultrasonication, forming kinetically stable oil-in-water dispersions. These mixtures were electrosprayed into calcium chloride baths, yielding monodisperse hydrogel beads. Higher alginate concentrations improved droplet sphericity and suppressed phase separation by enhancing matrix viscosity. The resulting beads exhibited stimuli-responsive degradation and controlled release behavior in response to physiological ionic strength. Dense alginate networks delayed ion exchange and prolonged structural integrity, while elevated external ionic conditions triggered rapid disintegration and immediate payload release. This simple and scalable system offers a biocompatible platform for the oral delivery of lipophilic active compounds without the need for surfactants or complex fabrication steps. Full article

Metabolic dysfunction-associated steatotic liver disease (MASLD) is one of the most prevalent chronic diseases in the world, lacking specific pharmacological interventions or well-established treatments. MASLD involves intricate pathological mechanisms characterized by oxidative stress and robust inflammatory responses. Selenium, an essential trace element, plays a critical role in antioxidation, regulation of inflammation, anticancer activity, and so on. Recent studies have reported that supplementation with selenium could alleviate MASLD and associated hepatic disorders, while excessive consumption may result in insulin resistance or even selenosis. Therefore, supranutritional selenium supplementation can be more suitable for the therapy and prevention of MASLD. This paper comprehensively reviews research about selenium and MASLD to highlight the potential applications and risks of supranutritional selenium supplementation in MASLD, following three steps: conducting a search, reviewing research articles and reviews, and discussing results. The keywords for the search include but are not limited to selenium, MASLD, supranutritional, hepatic diseases, selenoproteions, and selenium nanoparticles (SeNPs). We have reached the following conclusions: supranutritional selenium supplementation exhibits promising potential as a strategy to treat MASLD, but there are still some risks, depending on the dose and form of selenium; evaluating MASLD severity and selenium nutritional status accurately, as well as supplementing with superior forms of selenium (e.g., organic selenium and SeNPs), can further ensure the safety and efficacy of selenium supplementation. However, relationships between selenium homeostasis disorders and the occurrence and development of MASLD have not been fully elucidated. Methods for comprehensively assessing selenium status and mechanisms of selenosis require further investigation and research. Full article

This paper evaluates the synergistic effect of polyvinyl alcohol (PVA) fibers and nanosilica (nS) on the mechanical behavior and deformation properties of engineered cementitious composites (ECCs). ECCs have gained a reputation for high ductility, crack control, and strain-hardening behavior. Nevertheless, the next step is to improve their performance even more through nano-modification and fine-tuning of fiber dosage—one of the major research directions. In the experiment, six types of ECC mixtures were made by maintaining constant PVA fiber content (0.5, 1.0, 1.5, and 2.0%), while the nanosilica contents were varied (0, 1, 2, 3, and 5%). Stress–strain tests carried out in the form of compression, together with unrestrained shrinkage measurement, were conducted to test strength, strain capacity, and resistance to deformation, which was highest at 80 MPa, recorded in the concrete with 2% nS and 0.5% PVA. On the other hand, the mixture of 1.5% PVA and 3% nS had the highest strain result of 2750 µm/m, which indicates higher ductility. This is seen to be influenced by refined microstructures, improved fiber dispersion, and better fiber–matrix interfacial bonding through nS. In addition to these mechanical modifications, the use of nanosilica, obtained from industrial byproducts, provided the possibility to partially replace Portland cement, resulting in a decrease in the amount of CO₂ emissions. In addition, the enhanced crack resistance implies higher durability and reduced long-term maintenance. Such results demonstrate that optimized ECC compositions, including nS and PVA, offer high performance in terms of strength and flexibility as well as contribute to the sustainability goals—features that will define future eco-efficient infrastructure. Full article

Aluminothermic reduction is an alternative processing route for the circular economy because Al is produced electrochemically in the Hall–Héroult process with minimal CO₂ emissions if the electricity input is sourced from non-fossil fuel energy sources. This circular processing option attracts increased research attention in the aluminothermic production of manganese and silicon alloys. The Al₂O₃ product must be recycled through hydrometallurgical processing, with leaching as the first step. Recent work has shown that the NaAlO₂ compound is easily leached in water. In this work, a suitable slag formulation is applied in the aluminothermic reduction of manganese ore to form a Na₂O-based slag of high Al₂O₃ solubility to effect good alloy–slag separation. The synergistic effect of carbon and silicon reductants with aluminium is illustrated and compared to the test result with only carbon reductant. The addition of small amounts of carbon reductant to MnO₂-containing ore ensures rapid pre-reduction to MnO, facilitating aluminothermic reduction. At 1350 °C, a loosely sintered mass formed when carbon was added alone. The alloy and slag chemical analyses are compared to the thermochemistry predicted phase chemistry. The alloy consists of 66% Mn, 22–28% Fe, 2–9% Si, 0.4–1.4% Al, and 2.2–3.5% C. The higher %Si alloy is formed by adding Si metal. Although the product slag has a higher Al₂O₃ content (52–55% Al₂O₃) compared to the target slag (39% Al₂O₃), the fluidity of the slags appears sufficient for good alloy separation. Full article

Using common corn stalks as raw materials, a functional dense-structured carbon microsphere with good elastic deformation and certain rigid support was modified from biomass through a step-by-step hydrothermal method. The composition, thermal stability, fluid-loss reduction performance, and reservoir protection performance of the modified carbon microspheres were studied. Research indicates that after hydrothermal treatment, under the multi-level structural action of a small amount of proteins in corn stalks, the naturally occurring cellulose, polysaccharide organic compounds, and part of the ash in the stalks are adsorbed and encapsulated within the long-chain network structure formed by proteins and cellulose. By attaching silicate nanoparticles with certain rigidity from the ash to the relatively stable chair-type structure in cellulose, functional dense-structured carbon microspheres were ultimately prepared. These carbon microspheres could still effectively reduce fluid loss at 200 °C. The permeability recovery value of the cores treated with modified biomass carbon microspheres during flowback reached as high as 88%, which was much higher than that of the biomass itself. With the dense network-like chain structure supplemented by small-molecule aldehydes and silicate ash, the subsequent invasion of drilling fluid was successfully prevented, and a good sealing effect was maintained even under high-temperature and high-pressure conditions. Moreover, since this functional dense-structured carbon microsphere achieved sealing through a physical mechanism, it did not cause damage to the formation, showing a promising application prospect. Full article

In this study, the design and synthesis of a novel series of cinnamic acid and 1,2,4-triazole hybrids were reported, aiming to enhance antioxidant and lipoxygenase inhibitory activities through pharmacophore combination. Cinnamic acid derivatives and 1,2,4-triazoles exhibit a broad spectrum of biological activities; therefore, by synthesizing hybrid molecules, we would like to exploit the beneficial characteristics of each scaffold. The general synthetic procedure comprises three synthetic steps, starting from the reaction of appropriate substituted cinnamic acid with hydrazine monohydrate in acetonitrile with cyclohexane and resulting in the formation of hydrazides. Consequently, the hydrazides reacted with phenylisothiocyanate under microwave irradiation conditions. Then, cyclization proceeded to the 1,2,4-triazole after the addition of NaOH solution and microwave irradiation. All the synthesized derivatives have been studied for their ability (a) to interact with the free radical DPPH, (b) inhibit lipid peroxidation induced by AAPH, and (c) inhibit soybean lipoxygenase. The synthesized derivatives have shown significant antioxidant activity and have been proved to be very good lipoxygenase inhibitors. Compounds 4b and 4g (IC₅₀ = 4.5 μM) are the most potent within the series followed by compound 6a (IC₅₀ = 5.0 μM). All the synthesized derivatives have been subjected to docking studies related to soybean lipoxygenase. Compound 4g exhibited a docking score of −9.2 kcal/mol and formed hydrophobic interactions with Val126, Tyr525, Lys526, Arg533, and Trp772, as well as a π−cation interaction with Lys526. Full article

Extant core metabolic cycles such as the TCA cycle and its related analog pathways utilize carboxylic acids as metabolites, with thioesters playing a key role. We examine if sugars from the potentially autocatalytic formose reaction can be converted to carboxylic acids in the absence of enzymes by calculating the thermodynamics and kinetics of such pathways. We zero in on a mechanism involving the addition of a thiol to an aldehyde, followed by intramolecular disproportionation to form a thioester that can be hydrolyzed into its carboxylic acid. This route is thermodynamically favorable but can have kinetic bottlenecks. We find that elimination of H₂O or H₂S is often the rate-determining step, and that alpha di-carbonyl reactants that do not require such a step are more feasible in the absence of catalysts. Full article