Search Results (8,830)

The transition from conventional silica nanoparticle (SiNP) production based on purified alkoxysilanes and high-temperature flame hydrolysis of silicon tetrachloride to renewable and waste-derived silicon resources requires more than precursor substitution. It requires a mechanistic understanding of how feedstock mineralogy, silicon speciation, impurity chemistry, and processing history propagate through dissolution, nucleation, condensation, gelation, aging, drying, and pore evolution to determine material performance, environmental burden, and manufacturing feasibility. Although previous reviews have established the technical feasibility of producing silica from secondary resources, their predominant organization by feedstock, synthesis route, or application provides limited ability to explain why nominally similar processes generate materials with markedly different structural and functional properties. This review addresses these through a resource-pull, feedstock-to-function framework that links resource chemistry and process design to critical material attributes, application-specific specifications, sustainability, and scale-up requirements. Agricultural residues, industrial by-products, geothermal resources, waste glass, and fluorosilicate streams are critically compared according to silicon form and phase, reactivity, impurity profile, compositional variability, purification demand, and attainable product quality. Particular attention is given to waste-derived alkaline silicate systems, in which molecular, oligomeric, and colloidal silica coexist and therefore require characterization beyond bulk SiO₂ concentration. Established and emerging processing strategies, including controlled combustion and alkaline extraction, alkali fusion, ambient-pressure drying, microwave and mechanochemical activation, biogenic and biomimetic templating, and continuous processing, are evaluated according to their mechanistic effects, technological maturity, structural control, and demands for energy, reagents, water, solvents, effluent treatment, and capital. Across these routes, gelation and aging emerge as critical transfer stages through which feedstock composition is translated into network connectivity, pore architecture, shrinkage behavior, and ultimately functional performance. Evidence from secondary-source aerogels further shows that properly controlled waste-derived systems can attain BET surface areas of approximately 350–500 m² g⁻¹, within the textural range of many alkoxide-derived materials, indicating that feedstock variability, impurity management, and process control are more important constraints than an inherently lower performance ceiling. On this basis, this review proposes a minimum evidence framework comprising feedstock traceability, intermediate-speciation and colloidal characterization, silicon mass balance, gelation and aging metrics, application-specific qualification criteria, performance-normalized life cycle and techno-economic assessment, process analytical control, and staged pilot validation. Collectively, these principles provide a mechanistically grounded basis for moving sustainable silica synthesis beyond isolated proof-of-concept demonstrations toward reproducible, scalable, application-matched, and commercially credible manufacturing platforms. Full article

This study evaluates the effects of hydrogen enrichment of compressed natural gas (HCNG, CNG) on particle number emissions and particle size distribution in a dual-fuel compression-ignition (CI) engine. The experiments were conducted using a Fiat 1.3 MultiJet engine operated with conventional diesel fuel, diesel–CNG, and diesel–hydrogen-enriched CNG. Measurements were performed over a range of engine speeds, loads, and energy-substitution conditions. The hydrogen volume fraction in the gaseous fuel ranged from 5–10 vol.% to 53 vol.%. Particle size distributions were measured using an ELPI+ impactor. The use of CNG and hydrogen generally reduced soot-particle emissions in the accumulation mode, particularly within the particle-diameter range of approximately 0.03–0.2 µm. However, under some operating conditions, the number of ultrafine particles increased, particularly in the sub-23 nm range. This finding indicates a transition from a particle-formation mechanism dominated by soot formation and agglomeration to one dominated by nucleation and condensation. This phenomenon is associated with suppressed soot-precursor formation, enhanced soot oxidation by OH radicals, and a reduction in the surface area available for the condensation of volatile components. The effect of hydrogen depended on the engine operating point (EOP) and did not always scale linearly with hydrogen concentration. The results confirm that evaluating alternative fuels solely on the basis of particulate mass is insufficient. Particle number, particle size distribution, and the sub-23 nm fraction must also be considered. Full article

Epilobium parviflorum Schreb. is a medicinal plant used traditionally against inflammatory disorders whose cytotoxic potential is still incompletely revealed. The current study investigates the phytochemical composition and in vitro cytotoxic activity of four hydroalcoholic extracts prepared from the aerial parts of E. parviflorum by using maceration and Soxhlet extraction. The extracts were characterized in terms of total phenolic, flavonoid and tannins composition and LC-MS was used to identify its individual polyphenols. Their biological effects were assessed against four cancer cell lines (A375 melanoma, HT-29 colorectal adenocarcinoma, PANC-1 pancreatic carcinoma and SK-OV-3 ovarian adenocarcinoma cells), while using HaCaT keratinocytes as healthy cells in order to assess selectivity. Cell viability, cytoskeletal and nuclear morphology, mitochondrial respiration and network pharmacology were further investigated. A complex phenolic profile was revealed, with hyperoside being identified as the main component in all extracts while the extraction parameters strongly influenced the recovery of various phenolic compounds. All extracts reduced cancer cell viability in a dose-dependent manner after 24 h exposure, with the most pronounced effects observed at 720 and 1000 μg/mL, while HaCaT cells were left relatively unaffected. The morphological assessment indicated nuclear condensation, fragmentation and cytoskeletal disruption following the application of extracts. Moreover, high-resolution respirometry showed reduced oxidative phosphorylation and electron transfer system capacity thus indicating that early mitochondrial dysfunction may contribute to the cytotoxic effects. Network pharmacology revealed that ERBB2, CTNNB1, HSP90AA1 and HDAC6 might act as molecular targets in melanoma. Thus, these findings support the hypothesis that E. parviflorum hydroalcoholic extracts, particularly the 40% ethanol Soxhlet extract, may serve as important sources of bioactive phytocompounds with antiproliferative and apoptotic properties. Full article

To address the limited cooling range of ventilation in deep, high-temperature development headings and the lack of coordinated design between coil-based cooling and the ventilation system, this study proposes a coupled “twin-forcing–coil” cooling scheme. Building on conventional overlap (forcing–exhausting) ventilation, a rear-mounted second forcing duct is added to the conventional overlap (force–exhaust combined) auxiliary ventilation system, forming a dual-duct forcing, single-exhausting configuration—hereafter termed the “twin-forcing–single-exhausting” (TFSE) system—that provides a booster (relay) air supply to mitigate the along-path attenuation of cooling capacity and the short-circuiting of cold air; an in situ heat-exchange coil wall further provides supplementary cooling where ventilation-based temperature control weakens. Using a development heading at the 790 m level of a metal mine in Yunnan as the engineering background, a three-dimensional numerical model coupling the roadway, ventilation system, and coil wall was established and validated against nine field monitoring points, showing average relative errors of approximately 1% for temperature and 2–3% for humidity, comparable to the measurement uncertainty of the field instrumentation. Because the numerical model does not account for evaporative and condensation phase-change processes, two supplementary development headings with standing water at the face were used for validation; results showed that model error increases with water accumulation and heading length, indicating the model’s applicability is limited to conditions with intact surrounding rock and minimal seepage. Six operating cases were designed with duct placement and coil spacing as variables. Results show that single-duct ventilation cooling decays markedly beyond 30 m from the face, whereas twin-forcing booster (relay) air supply effectively extends the cooling range, reducing the 30–70 m section temperature by 2.7–2.9 K; the second duct should be positioned where the first duct’s cooling capacity begins to attenuate but is not yet depleted. Based on only two spacing configurations tested (10 m and 15 m), coil-staggered spacing showed limited effect on cooling performance under the field conditions examined; this preliminary finding requires validation across a broader range of spacings. Among the chilled-water conditions tested, an inlet temperature of 280.65 K and a flow velocity of 0.5 m/s offered a reasonable trade-off between cooling uniformity and economic efficiency. Under the boundary conditions and equipment parameters of this case, energy consumption estimates further indicate that the cooling effect per unit electricity consumption of twin-forcing ventilation is roughly 6–8 times that of coil-based cooling, primarily due to pumping losses over the ~240 m chilled-water delivery distance. This energy penalty indicates that coil-based cooling is better suited as a localized, short-distance supplementary measure rather than as a means of extending the cooling range over long distances. Full article

Mobile robots and autonomous vehicles require tightly regulated direct current (DC) power under rapidly varying load conditions, motivating control strategies that combine fast nonlinear regulation with predictive optimization. This paper proposes a Hybrid Sliding Mode Control and Model Predictive Control (Hybrid SMC + MPC) strategy for a DC-DC buck converter supplying a representative mobile-robot mission load. The controller employs a cascade SMC structure for fast inner-loop regulation and an MPC component that provides finite-horizon duty-cycle correction using planned load information. The MPC problem is formulated in condensed form and solved analytically without an external optimization solver. A Lyapunov-based analysis establishes a sufficient reaching condition for the sliding variable under the ideal averaged-model assumptions, and the condition is verified for the simulated mission. The proposed approach is evaluated in MATLAB using a 10-phase, 10 s load profile with resistance varying from 7 Ω to 100 Ω and is compared with SMC-only, MPC-only, PID, constant-duty, and reconstructed fuzzy-logic benchmarks. In the averaged-model study, the Hybrid SMC + MPC achieves a maximum absolute voltage deviation of 0.388 V, an RMSE of 0.0115 V, and a final-phase mean absolute error of 0.0076 V. It provides the lowest maximum voltage deviation among the principal closed-loop controllers, while PID achieves the lowest RMSE and final-phase error and SMC-only exhibits the shortest mean settling time. Relative to MPC-only, the Hybrid controller reduces the maximum voltage deviation by approximately 43.6% and the mean settling time by approximately 66.1%. An ablation study shows that the MPC contribution substantially improves overall and steady-state regulation accuracy, while load preview primarily reduces the worst-case voltage deviation. Switching-level MATLAB/Simulink validation with explicit 20 kHz PWM and converter parasitics confirms that the output remains within ±2% of the 25 V reference throughout the complete mission, with a maximum absolute deviation of 0.443 V and a maximum steady-state switching ripple of 21.6 mV peak-to-peak. These results demonstrate that the proposed Hybrid SMC + MPC architecture provides a favorable balance between worst-case transient regulation, steady-state accuracy, and predictive control capability for dynamically varying robotic power loads. Full article

Protein intrinsically disordered regions (IDRs) play important biological roles despite lacking stable structures. IDRs drive the formation of both biomolecular condensates via liquid–liquid phase separation (LLPS) and solid fibrous amyloid aggregates. Amyloids can be pathogenic and may exhibit self-perpetuating (prion) properties. Relationships between LLPS and the amyloid-forming and prion-propagating abilities of IDRs remain poorly understood. The N-proximal IDR of the yeast translation termination factor eRF3 (Sup35) can form both liquid condensates and heritable amyloid-based prions and serves as a powerful model for investigating these phenomena due to the availability of simple phenotypic, cytological and biochemical assays. Deletion analysis demonstrates that the N-proximal prion domain (Sup35N) of Sup35 is sufficient for chaperone-dependent prion propagation and that various regions of this domain show differential impacts on LLPS, amyloid aggregation, and prion inheritance. Specifically, the N-terminal NQ-rich stretch and the region of oligopeptide repeats are the most important contributors to the LLPS and formation of amyloid fibrils, while oligopeptide repeats and the C-terminal region of Sup35N are crucial for prion inheritance. Contrary to previous reports, the NQ-rich stretch is not required for prion formation and inheritance in yeast. Our data indicate that, in addition to amino acid composition, specific sequence motifs control reversible and heritable assemblies of Sup35. Full article

As crucial weather-scale systems widely affecting the global marine-atmospheric boundary layer, cyclones exert a regulatory effect on aerosols in the marine boundary layer through interrelated physical and chemical processes, including dynamic uplift, strong wind forcing, precipitation scavenging, and cloud microphysical interactions. Following an overview of aerosol properties in the marine boundary layer and synoptic cyclone characteristics, this paper reviews the full-process regulation mechanisms and mutual feedback effects of tropical and extratropical cyclones on aerosol generation, long-range transport, and removal, integrating the latest advances in observational, numerical, and theoretical studies. Cyclone-driven aerosol generation has two key pathways: mechanical fragmentation of sea surfaces in cyclones’ strong wind cores, emitting sea salt aerosols of varying particle sizes, and cyclone-induced disturbances triggering photochemical and heterogeneous reactions that accelerate secondary aerosol formation. Cyclone movement, with strong advection and updrafts, enables cross-ocean long-distance transport and upper troposphere injection of aerosols in the marine boundary layer, altering their global distribution. Wet deposition (rainout and washout) is the dominant removal mechanism, eliminating aerosols and mediating the cyclone–aerosol–cloud feedback loop, where aerosols as cloud condensation nuclei or ice nuclei regulate cyclone intensity, precipitation, and cloud cover. Current challenges (e.g., emission quantification uncertainties, incomplete microphysical understanding, model limitations) and prospects (e.g., enhanced long-term observations, improved model parameterization) are discussed. This review provides a scientific basis for aerosol-climate effect studies under extreme weather and references for related fields. Full article

Wood vinegar (WV), also known as pyroligneous acid, is the aqueous condensate produced during lignocellulosic biomass pyrolysis, generated alongside biochar and non-condensable gases. In forest biorefineries, it represents a promising value-added coproduct capable of transforming forestry and agroforestry residues into a multifunctional bioproduct. Its composition, dominated by water, organic acids, phenolic compounds, aldehydes, and ketones, confers antimicrobial, antioxidant, biostimulant, herbicidal, and preservative properties. This review critically examines WV production, chemical composition, purification strategies, mechanisms of action, and applications, explicitly distinguishing evidence-based uses from prospective ones. Current evidence supports applications in agriculture, wood preservation, environmental management, and forestry, including forest nursery production and clonal propagation of Eucalyptus and Pinus. However, the literature remains fragmented by compositional variability, non-standardized terminology, limited mechanistic understanding, and scarce long-term toxicological and techno-economic assessments. WV holds significant potential for sustainable biomass valorization and circular bioeconomy strategies. Realizing this potential requires harmonized analytical protocols, standardized formulations, rigorous mechanistic studies, life-cycle assessments, and regulatory frameworks that support the transition of this heterogeneous pyrolysis byproduct into a reliable commodity within integrated forest biorefineries. Full article

Mechanical force offers a distinctive nonequilibrium mode of energy input for lignocellulosic biomass valorization through localized, transient action. This review systematically examines the multiscale physicochemical effects of mechanical force, its synergistic coupling with chemical pretreatments, and its role in enhancing enzymatic hydrolysis. The principal contribution of mechanical force is not merely particle-size reduction, but the exposure of active sites and improvement in substrate accessibility at the molecular level. Coupling mechanical force with chemical pretreatment enables the efficient component fractionation under mild conditions while mitigating irreversible lignin condensation. In high-solids enzymatic hydrolysis, a periodic mechanical energy input can tear fiber bundles, release constrained water, and renew reaction interfaces, thereby allowing enzymes to sustain a high catalytic efficiency at extremely low liquid-to-solid ratios and reducing the dependence on large amounts of free water. An economic analysis indicates that feedstock and enzyme costs dominate the overall process economics. Accordingly, mechanical-force strategies should prioritize the maximized sugar yield and reduced enzyme loading under a controlled energy input. Future research should focus on continuous operation, the balance between mechanical deconstruction and lignin structural integrity, and multidimensional evaluation frameworks that integrate the energy consumption, sugar yield, enzyme dosage, and full-process energy balance. Full article

Nuclear relaxation, $1/T_1$, is a very robust probe of electronic excitations in superconducting materials above and below the critical temperature of superconductivity, $T_{\mathrm{c}}$. Here, a relaxation phenomenology of hole-doped cuprate superconductors is presented based on the majority of the available literature data from the CuO₂ plane, without assumptions with respect to a hyperfine scenario, form factors, or particular theoretical models. Below a temperature similar to the pseudogap temperature, Heitler–Teller-type relaxation is uncovered universally; i.e., the nuclear spin relaxation above $T_{\mathrm{c}}$ is only determined by the absolute temperature, $1/T_1\propto T$. All materials condense out of this metal at $T_{\mathrm{c}}$, below which relaxation drops even faster, as expected from conventional superconductors, albeit without a Hebel–Slichter peak. It is a ’hidden metal’ in the sense that it has a vanishing uniform response and thus hardly affects the NMR shifts; it is also not seen in planar O relaxation. The hidden metal causes a temperature-independent but material-dependent planar Cu relaxation anisotropy that is strongly correlated with the size of $T_{\mathrm{c}}$. Moreover, the rate measured with the field in the CuO₂ plane is nearly the same for all cuprates: $1/{{}^{63}T}_{1\perp }T\approx 25/$Ks, where $1/{{}^{63}T}_{1\Vert }$ is mainly responsible for the change in anisotropy. Above the hidden metal, the relaxation behavior changes and can be described by an ordinary but renormalized metal, with a reduced Cu relaxation anisotropy. The relaxation phenomenology, which should hold clues to the so-called strange metal, is also discussed in the context of the two spin components previously uncovered in the shifts, as well as the pseudogap and relation to other probes. This new phenomenology should give a better foundation for the understanding of the cuprates. Full article

Novel and efficient total syntheses of the nonsteroidal anti-inflammatory drugs Pelubiprofen and Loxoprofen via a photo-Favorskii rearrangement are reported herein. The key photochemical transformation was optimized under both batch and continuous-flow conditions using a suitably functionalized chloro-phenylpropan-1-one derivative, affording the target 2-arylpropionic acid in excellent yield. Implementation under continuous-flow conditions increased process productivity and enabled gram-scale operation. Aerobic oxidation of the benzylic position to the corresponding aldehyde, followed by Claisen–Schmidt condensation with cyclohexanone, afforded Pelubiprofen in 35% overall yield. Alternatively, condensation with cyclopentanone afforded the corresponding α,β-unsaturated enone intermediate, whose selective reduction under flow conditions enabled access to Loxoprofen in 28% overall yield. The versatility of the methodology was further demonstrated through the synthesis of Carprofen, highlighting the broader applicability of the photo-Favorskii rearrangement to the synthesis of APIs through previously unreported synthetic routes. Full article

Highly pathogenic RNA viruses, such as Ebola, SARS-CoV-2, and influenza, cause severe disease in humans. High mutation rates, which enable RNA viruses to evade immunity and escape antivirals, and their ability to spread from animals to humans and cause pandemics and outbreaks, make RNA viruses significant threats to public health. Diseases caused by Ebola, SARS-CoV-2, and influenza are prevented and treated with only a limited number of approved antiviral drugs, the effectiveness of which is limited by mutations in the viral targets. It is crucial to understand the structural determinants, molecular mechanisms, and host interactions of pathogenic RNA viruses to develop effective antiviral strategies. In this review, we discuss selected RNA viruses, focusing on the structure of their RNA polymerases and interactions with host factors during the different stages of the viral lifecycle, as well as the traditional antivirals targeting these structures and pathways. Furthermore, emerging concepts such as liquid–liquid phase separation and biomolecular condensates, and novel promising antiviral strategies are discussed. Understanding shared and distinct structures, molecular mechanisms, and host interactions across highly pathogenic RNA viruses enables the discovery of new and more effective antiviral strategies, ultimately improving clinical outcomes against evolving RNA viruses. Full article

Punica granatum L. (pomegranate) is one of the oldest medicinal plants known to humankind, valued across ancient civilisations for treating parasitic, microbial, and metabolic diseases. Its exceptionally rich phytochemical composition, dominated by punicalagins, ellagic acid, anthocyanins, flavonoids, piperidine alkaloids, and the unique conjugated fatty acid punicic acid, confers a remarkably broad spectrum of biological activities of direct relevance to contemporary veterinary medicine. While human-health applications have been extensively reviewed, a comprehensive synthesis of veterinary evidence across multiple species remains lacking. This review consolidates current preclinical and field knowledge on the pharmacological effects of pomegranate preparations in poultry, ruminants, swine, fish, companion animals, and laboratory models. In poultry—the most extensively studied taxon—dietary inclusion of pomegranate peel powder or extract consistently enhances growth performance, antioxidant status, and humoral immunity while exerting meaningful anticoccidial activity. The antiparasitic properties are compellingly supported by evidence against gastrointestinal nematodes of ruminants, tapeworms, schistosomes, and protozoa including Giardia, Cryptosporidium, and Leishmania spp., as well as monogenean fish parasites. Broad-spectrum antimicrobial activity extends to major veterinary pathogens such as Salmonella, Escherichia coli, Staphylococcus aureus (including MRSA), and Clostridium perfringens. Rodent models have validated antidiabetic, hepatoprotective, nephroprotective, and reproductive benefits, including improved post-thaw sperm quality and enhanced litter size. The safety profile is generally favourable at conventional doses, although high dietary inclusion elicits anti-nutritional effects from condensed tannins, and potential drug interactions via cytochrome P450 inhibition warrant clinical caution. Despite this substantial evidence, significant translational barriers persist, including extract heterogeneity, absence of pharmacokinetic data in target species, and scarcity of controlled clinical trials. By providing a species- and pathology-driven synthesis, this review identifies critical research priorities and highlights the immense potential of this ancient, accessible, and economically viable phytobiotic as a natural alternative to antibiotic growth promoters and synthetic antiparasitics in veterinary practice. Full article

Enhanced circular tubes are widely employed in shell-and-tube heat exchangers, power-generation condensers, chemical reactors, refrigeration systems, and air-cooled heat exchangers, where improved convective performance can reduce the heat-transfer area required for a specified thermal duty. Helical screw tapes (HSTs) are passive inserts that promote sustained swirling motion and enhance convective heat transfer within such tubes. Although helical screw tapes and multiple-insert arrangements have been investigated previously, the combined thermohydraulic and second-law effects of increasing the number of co-rotating HSTs under fixed geometric ratios remain insufficiently quantified. In this investigation, turbulent airflow in a heated round tube was numerically investigated to examine the effect of tape number on heat transfer, pressure drop, thermal performance, total entropy generation (S_total), and exergy destruction (Ex_D). Six HST configurations containing one to six tapes were examined over a Reynolds-number range of Re = 5000–20,000 in a circular tube with an inner diameter of D_T = 31 mm, which was also adopted as the characteristic length for the Reynolds number, Nusselt number, and friction factor. The helical pitch P, screw diameter D_s, tape width W, and tape thickness t were 60 mm, 30 mm, 4.5 mm, and 0.2 mm, respectively, giving a pitch ratio of P/D_s = 2.0 and a width ratio of W/D_s = 0.15. A plain tube (PT) served as the baseline case. The results show that increasing the number of tapes intensifies swirl flow and enhances heat transfer but also leads to a continuous increase in pressure loss. For the optimum three-tape arrangement, the Nusselt number is increased by 126.0–158.8% and the thermal performance factor by 4.5–19.5% relative to the plain tube, while the total entropy generation and exergy destruction are simultaneously reduced by 7.9–61.0%. Among the configurations examined, HST-P2.0-W0.150-3, comprising three tapes at a pitch ratio of P/D_s = 2.0 and a width ratio of W/D_s = 0.15, achieved the best overall performance by delivering the highest thermal performance factor and the lowest total entropy generation and exergy destruction among the HST cases. Full article

Biomolecular condensates are dynamic membraneless organelles composed of proteins and RNAs that assemble through multivalent interactions and provide cells with powerful means to regulate gene expression in space and time. Different epitranscriptomic marks such as m⁶A, m¹A, and m⁵C can reshape RNA structure—binding interfaces and multivalency and, in this manner, tuning which transcripts nucleate or partition into specific condensates and influencing their material state. This review summarizes how individual RNA modifications and their associated proteins regulate the formation and function of BMCs such as stress granules, P-bodies, nuclear bodies and disease-linked condensates in cancer and neurodegeneration. It highlights emerging concepts of combinatorial “epitranscriptomic codes” and bidirectional feedback between condensates and RNA-modifying enzymes and discusses the current experimental and technical gaps that still limit our understanding of modification crosstalk and condensate topology. Full article