Search Results (791)

Dye-sensitized solar cells (DSSCs) remain attractive as low-cost photovoltaic devices; however, their practical efficiency is still constrained by electron-transport losses, interfacial recombination, and incomplete light harvesting in conventional titanium dioxide (TiO₂) photoanodes. The effects of TiO₂ film thickness, multi-walled carbon nanotube (MWCNT) incorporation, and multilayer oxide interface engineering on DSSC performance were examined. Degussa P25-TiO₂ photoanodes were first optimized with respect to thickness, after which controlled MWCNT loadings and sequential compact sol–gel TiO₂ and tin dioxide (SnO₂) sublayers were introduced. The optimum pristine P25-TiO₂ photoanode thickness was 9.11 μm, yielding an open-circuit voltage of 0.74 ± 0.01 V, a short-circuit current density of 14.10 ± 0.40 mA/cm², a fill factor of 56.24 ± 1.00%, and a power-conversion efficiency of 5.93 ± 0.20%. The incorporation of 0.025 wt% MWCNTs increased the efficiency to 6.04 ± 0.20%, corresponding to an absolute gain of 0.11 percentage points. The best performance was obtained with the sol–gel SnO₂/sol–gel TiO₂/P25-CNT multilayer photoanode, which delivered 0.74 ± 0.02 V, 16.22 ± 0.40 mA/cm², 57.59 ± 1.00%, and 6.89 ± 0.30%, respectively. FE-SEM, EIS, XRD, Heated Ultrasonic Cleaner and UV–visible analyses indicate that the multilayer architecture preserves porosity, enhances light harvesting, and suppresses interfacial recombination, while the CNT network facilitates charge transport. Full article

Conventional chemical gel plugging materials often suffer from poor high-temperature stability and inadequate mechanical properties. To address these issues, this study developed a high-performance composite gel material using a multi-component hybrid crosslinking strategy. The material employs γ-methacryloxypropyltrimethoxysilane (MPTMS) as the silica source, which hydrolyzes in situ to generate SiO₂, thereby enhancing temperature resistance. Laponite nanoplatelets are incorporated as a toughening agent and physical crosslinking points, while a self-synthesized reactive microgel (BWL) serves as the organic crosslinking core. Through copolymerization with monomers such as acrylamide (AM) and methacrylic acid (MAA), a triple-crosslinked network structure is constructed. Compared with conventional gels, the synthesized hybrid crosslinked composite gel maintains a high storage modulus and loss modulus after aging at 140 °C and exhibits excellent tensile and compressive properties. Furthermore, the gel was processed into particle-based lost circulation materials with different particle sizes. High-temperature and high-pressure plugging experiments demonstrate that when using a mixed system of 40–60 mesh, 20–40 mesh, and 10–20 mesh gel particles with a total concentration of 2%, it can effectively seal highly permeable sand beds and fractures with apertures up to 5 mm. This meets the engineering requirements for lost circulation materials with high strength and high stability in deep, high-temperature formations. Full article

Neurodegenerative diseases arise when normally functional aggregation-prone proteins transition into stable cross-β amyloid fibrils. Although these fibrils share a conserved architecture, the pathways that lead to fibrillation vary across proteins and cellular environments. Liquid–liquid phase separation is now recognized as a central organizer of intracellular biochemistry that modulates protein aggregation. Physiological condensation can buffer aggregation by maintaining macromolecular solubility and providing partner interactions that compete against pathological protein–protein interactions. However, condensates can transform and age into gel-like states that can favor the emergence of β-rich oligomers and solid-state fibrils. Across six disease-linked proteins that include Tau, α-synuclein, amyloid-β, TDP-43, FUS, and hnRNPA1, we compare how sequence-encoded interaction motifs, cellular cofactors, and interfacial microenvironments shape the balance between physiological condensates and pathological amyloids. Here, we highlight the unifying drivers of aggregation and intervention points that preserve native function while limiting toxic amyloid formation. Full article

Dry electroencephalography (EEG) electrodes enable rapid, gel-free setups, which are crucial for point-of-care diagnostics, but often face challenges with comfort and signal quality—especially in a clinical context. Novel “flower” dry electrodes are a special type of reusable scalp electrodes for dry EEG, featuring a distinct flower-like shape with angled pins in three intertwined layers. While the new electrode design has been validated in an in vivo study on healthy volunteers, we tested its clinical applicability in a proof-of-concept study involving three patients diagnosed with epilepsy and delirium. The recordings were of high diagnostic quality, enabling the reliable identification of pathological patterns, such as generalized spike–wave complexes and intermittent delta activity, with a signal-to-noise ratio comparable to prior reports for sponge-based EEG systems (limited case series). The signal-to-noise ratio (SNR) proved to be sufficiently high for clinical diagnostic purposes, resulting in visually clear and interpretable EEG data that enabled effective assessment of patients’ neurophysiological signals. Consequently, our findings demonstrate that the comfortable flower-electrode design is a viable and effective tool for epilepsy diagnostics, extended recording, and clinical neurophysiology. It represents a significant step towards patient-centered and gel-free EEG technology, specifically in point-of-care and emergency applications, without compromising the diagnostic quality of the recordings. Full article

The primary objective of this study is to investigate the effect and mechanism of replacing limestone powder with red mud as a filler on asphalt aging resistance. The microstructure and porosity characteristics of limestone powder, Bayer process red mud, and sintered red mud were analyzed. Asphalt mastics were then prepared using these fillers. The effect of red mud on the aging resistance of asphalt was evaluated by comparing the conventional physical properties, rheological behavior, and functional groups of the asphalt mastics before and after aging. Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and ultraviolet-visible spectroscopy (UV-Vis) were further employed to elucidate the underlying anti-aging mechanisms. The results indicate that the asphalt mastic containing 4% sintered red mud exhibits the strongest resistance to both thermo-oxidative and UV aging. It shows the lowest increments in softening point, viscosity aging index, and complex modulus aging index, with performance comparable to a commercial anti-aging agent. FTIR and GPC analyses reveal that sintered red mud selectively adsorbs light asphalt components, thereby inhibiting their conversion into heavier fractions during thermo-oxidative aging. UV-vis analysis demonstrates that sintered red mud provides effective UV shielding within the asphalt mastic, substantially mitigating UV-induced damage. In summary, the incorporation of 4% sintered red mud can significantly delay both thermo-oxidative and UV aging processes in asphalt mastics, thereby effectively enhancing the aging resistance of asphalt pavement. Full article

As global oil and gas exploration extends to deep and ultra-deep wells, high bottom-hole temperature is prone to deteriorating the gelation and rheological properties of water-based drilling fluids, which manifests as undesirable thickening or thinning at elevated temperatures. Therefore, the development of high-temperature resistant and stable drilling fluids is crucial for ensuring safe and efficient drilling operations, and the enhancement of high-temperature performance is typically achieved by adding drilling fluid treatment agents. The main objective of this study is to apply sodium acetate (SA) to drilling fluid systems, developing an economical and efficient non-polymer treatment agent with dual functions as a composite sodium-modifier and a rheological regulator. By-product sodium acetate (TRSA) is adopted to provide better cost-effectiveness while maintaining equivalent performance, and its universality across seven types of bentonites is verified. Three grades of sodium acetate were added to the bentonites as either composite sodium-modifiers or rheological regulators. After high-temperature aging, rheological parameters, including mud density, plastic viscosity (PV), yield point (YP), and gel strength, were measured in accordance with standard API methods. The results indicate that adding 2 wt.% TRSA to drilling fluid and subjecting it to hot rolling at 180 °C for 16 h keeps the viscosity at a high shear rate (1022 s⁻¹) nearly unchanged (from 36 mPa·s to 37.5 mPa·s), while increasing the viscosity at a low shear rate (5.11 s⁻¹) from 250 mPa·s to 1400 mPa·s, thereby effectively improving the shear thinning effect of the sodium-modified calcium-based bentonite water-based drilling fluid. Although TRSA increases the filtration loss from 21.8 mL to 30 mL, this can be reduced to 20–25 mL by co-extrusion sodium modification with sodium carbonate or by adding additional TRSA to sodium-modified bentonite. This study provides a novel perspective for significantly improving the gelation characteristics and rheological properties of bentonite suspensions at high temperatures through a special inorganic substance, while realizing resource reuse and cost reduction. Full article

The sustainable valorization of citrus processing by-products represents a key challenge for the food industry, aiming to reduce waste while recovering valuable bioactive compounds. In this study, a cloud point extraction strategy was developed using soy lecithin as a natural, food-grade surfactant to isolate phenolic antioxidants from orange juice industry residues. Response Surface Methodology was applied to two streams of orange juice by-products, to evaluate the combined effects of pH, NaCl concentration, and lecithin content on extraction efficiency, with total polyphenolic content, DPPH radical scavenging activity, and ferric reducing antioxidant power serving as response variables. Partial Least Squares (PLS) analysis was additionally employed to integrate all antioxidant responses and identify a multivariate optimum. The optimized conditions (pH 3.4, 12% NaCl, 11% lecithin) enabled maximal recovery of antioxidant constituents, highlighting the effectiveness of lecithin-based micellar systems. To assess practical applicability, the optimized extract from the oil emulsion residue (Stream A) was incorporated into tsipouro, a traditional Greek distillate, and its stability was monitored under controlled light and temperature conditions for 30 days at three concentration levels. Results demonstrated that both environmental factors significantly influenced antioxidant retention and physical stability, underscoring the importance of formulation design. Specifically, high gel concentration at 2% w/v, low temperature at 20 °C and light exposure provided the highest overall desirability for TPC, FRAP, and DPPH responses. Overall, this work introduces a green, scalable, and food-compatible extraction approach that not only supports circular economy principles but also opens new opportunities for the development of functional alcoholic beverages enriched with natural antioxidants. Full article

Real-time PCR (qPCR) is today’s definitive quantitative technology in molecular biology and diagnostics. Until 30 years ago, PCR product analyses were generally performed after amplification using gel-based methods. Quantification typically relied on visual inspection or densitometry of end-point products and was therefore relatively unreliable and poorly suited to high-throughput automation. To celebrate real-time PCR’s 30-year anniversary of commercial availability, Professor Stephen Bustin, Guest Editor for the special edition, “Advancing Molecular Science Through Reproducible qPCR: MIQE Guidelines and Beyond,” asked Russell Higuchi to give a historical account on how his idea of real-time PCR was conceived and brought to fruition. Dr. Higuchi then asked his collaborator, Lincoln McBride, who drove the development of the ABI 7700—the high-throughput real-time PCR instrument that gave researchers access to this technology—to co-author this dual memoir. This story is told from the perspectives of the two scientists most directly responsible for making real-time PCR practical and widely accessible. Taking turns, Russell Higuchi describes the conceptual and experimental steps at Cetus and then Roche that led from homogeneous PCR detection to continuous fluorescence monitoring, whilst Lincoln McBride details ABI’s parallel efforts to commercialize Russ’s invention. Together, they trace how experimental insight, engineering constraints, product development, and commercial decision-making shaped the Applied Biosystems 7700 Sequence Detection System and established real-time PCR as a practical and reliable quantitative technology. Their team’s efforts persevered through technological uncertainty and within a complex corporate collaboration. They share key historical documents in their original form. Their accounts show how the 7700 system emerged as the convergence of chemistry, optics, software, and product development. The eventual global reliance on real-time PCR during the COVID-19 pandemic demonstrated, at unprecedented scale, the profound and enduring impact of these early technical and organizational choices. Full article

In this study, by using four different silicon sources obtained from Konya, Turkey, and its surroundings and employing the sol–gel method, we aim to synthesize silica-based aerogel, characterize it, and improve the use of the innovative building material as a thermal insulator in architectural applications. In this direction, silica aerogel production was carried out using four different starting materials (commercial casting sand, waste casting sand, radiolarite, and quartz) and five different pH values (2–4–6–8–9) by the sol–gel method. The produced silica aerogels were subjected to a surface modification process with Trimethylchlorosilane (TMCS), a modification chemical, and then superhydrophobic silica aerogel powder was obtained. In terms of characterization of the obtained final silica aerogels, XRF, XRD, ICP-OES, density study, FT-IR, BET, FESEM, and contact angle studies were performed. In terms of application of the architectural building material, plasterboard experimental samples were produced using low reinforcement rates (0 wt%, 0.5 wt%, 1 wt%, 2 wt%, and 5 wt%) of silica aerogel. To determine the mechanical and physical properties of the produced silica-aerogel-reinforced plasterboard samples, three-point bend (flexural) strength, compressive strength, thermal conductivity, and water absorption tests were applied. After surface modification, the lowest density value was 0.340 g/cm³, the highest surface area was 311.161 m²/g, and the lowest thermal conductivity coefficient was 0.29 W/mK in silica aerogel material containing radiolarite. In addition to high reinforcement contents in the literature, when it comes to silica aerogel low-reinforcement material and mechanical properties, it can be stated that increasing reinforcement contents negatively affects the mechanical behavior of the material after a certain value. Full article

Polylactide (PLA) has become widely adopted across biomedical, packaging, and manufacturing sectors due to its biodegradability and renewable sourcing. However, the rapid growth in PLA consumption has created urgent challenges related to waste management and the cleaning of processing equipment. This study investigates glycolysis as a promising chemical depolymerization pathway for PLA recycling and in situ reactor cleaning. A systematic analysis of four glycolysis agents (GA) (ethylene glycol, diethylene glycol, propylene glycol, and glycerol) was performed across molar PLA:GA ratios from 1:0.125 to 1:4 at 220 °C, targeting the efficient conversion of high-molecular-weight PLA (Mn ≈ 165 kDa) into low-molecular-weight oligomers. Gel permeation chromatography (GPC) demonstrated that propylene glycol exhibited the highest depolymerization efficiency, yielding oligomers with Mn as low as 200 g·mol⁻¹ even at minimal glycolysis agent ratios, while glycerol produced hydroxyl-rich oligomers optimal for subsequent lactide synthesis. Hydroxyl value (HV) measurements showed excellent agreement with theoretical values (<5% deviation), allowing us to make an assumption about an approximate, close to near-quantitative con-version. Glycolysis products with Mw below 400 g·mol⁻¹ displayed excellent water solubility, making them particularly attractive for reactor cleaning applications. Using glycerol-derived (GL) oligomers (PLA:GL = 1:0.25), purified L-lactide with a melting point of 98.1 °C and high purity (>99%) was obtained through thermocatalytic depolymerization and five recrystallization cycles, as confirmed by ¹H nuclear magnetic resonance (¹H NMR) and differential scanning calorimetry (DSC) analyses. The recovered lactide’s high purity renders it suitable for ring-opening polymerization, enabling closed-loop PLA recycling schemes. Overall, glycolysis emerges as a highly promising chemical recycling route complementary to hydrolysis and pyrolysis: propylene glycol maximizes depolymerization efficiency for cleaning applications, while glycerol optimizes oligomer functionality for lactide recovery and advanced material synthesis. Our results provide practical guidelines for selecting glycolysis agents and conditions for cleaning and recycling applications. Full article

The design of new medical devices in biomedical engineering often necessitates the control of microbial load at the point of application, making antibacterial action valuable for numerous applications in the biomedical field. Nanotechnology products, such as silver nanoparticles (AgNPs), represent highly promising yet underexplored bioactive and antimicrobial agents that have attracted researchers’ interest for integration into medical devices. This study focuses on stable suspensions of silver nanoparticles, characterized by using a range of complementary physicochemical techniques as well as bacterial cell cultures, while also demonstrating controlled entrapment of the nanoparticles in collagen-based gels. The findings reveal that highly stable suspensions of negatively charged AgNPs (~6 nm in size) consistently exhibit broad-spectrum antimicrobial activity against both Gram-negative and Gram-positive bacteria, with minimum inhibitory concentration values of 10–20 ppm, whilst, importantly, close contact between the nanoparticles and bacterial cells turns out to be essential for their antibacterial action. Controlled entrapment of the nanoparticles in collagen-based gels enables regulation of nanoparticle release and their antimicrobial efficacy. This work highlights the promising prospects of silver nanoparticles in designing novel biomedical engineering products, while underscoring the need for a more comprehensive understanding of their biological activity to ensure optimal utilization. Full article

Barite sag remains a persistent challenge in water-based drilling fluids, particularly in high-pressure, high-temperature and deviated wellbores where density variations can compromise well control, hole cleaning, well stability and operational safety. Conventional weighting materials often fail to maintain suspension stability under such demanding conditions, highlighting the need for anti-sag solutions. This study presents a systematic evaluation of in-house synthesized barite nanoparticles (26.9–63.2 nm) manufactured using ball milling and incorporated into drilling fluids at concentrations of 0%, 3%, and 5% across densities of 9, 12, and 15 ppg. Using standardized API procedures, the fluids were assessed for rheology, filtration behavior, and sag tendency under both dynamic and static HPHT conditions to mimic realistic drilling environments. Results show that a 5% nanoparticle concentration significantly enhances drilling fluid performance, improving plastic viscosity (up to 50%), yield point (up to 51%), and gel strength (up to 80%), while also reducing fluid loss by 9–10% and mud cake thickness by up to 16%. Moreover, barite sag was substantially mitigated, with dynamic sag reductions of 10–50% and static sag reductions of up to 21% in inclined HPHT conditions. The novelty of this work lies in the comprehensive testing approach, from a practical perspective, covering the effect of an engineered barite nanoparticle to demonstrate a scalable and practical method to enhance sag resistance, suspension stability, and overall drilling efficiency. Full article

Growing demand for low-sodium surimi products has driven the search for safe salt alternatives. Anionic peptides (APPs) and cationic peptides (CPPs) were isolated from sheepskin collagen via Diethylaminoethyl (DEAE) chromatography. CPPs contained higher arginine (46.11%) and lysine (4.64%) than APPs (40.57% and 3.99%, respectively), while APPs were enriched in acidic amino acids like glutamic acid (3.88%). Comprehensive evaluations of low-salt silver carp surimi gels showed both peptides significantly improved gel strength and water-holding capacity (WHC). The water-holding capacity increased from 60.68% in the blank control group to 74.31% in the CPP-treated group, while that in the APP-treated group was 66.86%. Cooking loss was significantly reduced, decreasing from 40.64% in the blank control group to 28.57% in the CPP-treated group and 34.52% in the APP-treated group. The samples achieved a quality comparable to that of the NaCl-supplemented group, with CPP outperforming APP in terms of hardness and gel network density. The LF-NMR confirmed enhanced water retention by reducing free water (T₂₂) and increasing bound water (T₂b). The FTIR indicated a conformational shift from α-helix to β-sheet, and the SEM revealed denser networks with fewer large voids. The SDS-PAGE demonstrated enhanced myosin heavy chain (MHC) cross-linking, more pronounced in the CPP-treated samples. CPPs exerted stronger electrostatic attraction with negatively charged surimi proteins (isoelectric point 5.5), while APPs chelated Ca²⁺ to activate transglutaminase. These findings validate APPs and CPPs as promising salt substitutes, enabling low-sodium surimi production and high-value utilization of sheepskin by-products. Full article

According to the EFSA Report on Zoonoses (2024), yersiniosis was classified as the fourth most commonly reported zoonosis in humans in 2023, with a 13.5% increase in yersiniosis infections compared to 2022. In 2024, the findings were consistent with the 2020–2023 trend. Isolation and identification of enteropathogenic Yersinia is difficult and time consuming, especially when examining food and environmental samples. Among them, Y. pseudoturbeculosis poses a challenge due to the lack of a single selective medium for all bioserotypes. Therefore, faster methods for the detection of Yersinia spp. need to be implemented into the praxis. Rapid identification of pathogens in food or at the time and location of the epidemiological outbreak (point-of-care testing) enables either prevention of the outbreak or early stage diagnosis and prompt decisions. The loop-mediated isothermal amplification (LAMP) is increasingly coming to scientists’ attention as a robust and rapid methodology for pathogen detection in laboratories with limited resources and equipment. The aim of current study is to evaluate, for the first time, the sensitivity of the LAMP protocol based on colorimetric detection in the visible spectrum in comparison with that of the digital droplet PCR (ddPCR). For this aim, a series of decimal logarithmic dilutions of the pathogen Y. pseudotuberculosis in artificially contaminated raw goat milk was used. One commercial LAMP kit with two different dyes (one dsDNA-binding and one Mg²⁺-sensitive) was compared to the sensitivity of the detection to ddPCR. The results obtained revealed a high sensitivity of the kit for detection of DNA isolated from artificially contaminated milk samples in the following range: visible detection based on visible color change—3.1 × 10⁴ mL (violet dye) and 3.4 × 10³/mL (blue dye); detection with gel electrophoresis—2.0 × 10¹/mL (violet dye) and 3.4 × 10²/mL (blue dye). The enumeration of the DNA copies in the same samples was performed with ddPCR, with a detection limit of 2.0 × 10¹/mL. Our results indicate the potential and the possible applicability of the LAMP method for rapid and sensitive visual detection of Y. pseudotuberculosis in raw goat milk. The presented ddPCR protocol can be used for highly sensitive identification and enumeration of Y. pseudtuberculosis in raw goat milk. In conclusion, the conducted comparison is of importance for future implementation of LAMP protocols for on-field analysis near the sampling site and point-of-care or laboratory diagnostics of Y. pseudtuberculosis after the successful validation procedure of an appropriate LAMP protocol. Full article

The growing demand for clean-label plant-based cheese alternatives underscores the need for products with desirable properties. A key technological challenge is replicating the firmness of traditional cheese without synthetic additives. This study explores lactic acid bacteria (LAB) fermentation as a natural texturizing method for clean-label plant-based cheeses. We investigated the link between LAB metabolic traits and the firmness of three substrates: cashew, soybean, and sunflower seed. A strong correlation (r ≈ −0.88) was found between final pH and firmness in cashew paste, where strains achieving a pH of ~4.0–4.5 (near the protein isoelectric point) produced the firmest gels (up to 3.35 N). Lactiplantibacillus plantarum 729/23 and Lacticaseibacillus helveticus NK-1 were most effective. Soybean paste firmness increased moderately (to 1.93 N), while sunflower seed paste showed no significant improvement (≤1.14 N) despite active acidification, indicating substrate-specific limitations. This study, supported by a comprehensive analysis of the literature on firmness measurement in plant-based cheeses, demonstrates the potential of targeted selection of natural starter cultures to create clean-label products with minimal ingredients. Full article