Search Results (674)

Coastally Trapped disturbances (CTDs) are shifts in wind direction from the pre-dominant direction to equatorward to poleward for a period of time. These CTDs occur during the warm season off the California coast and impact coastal weather conditions and planned offshore wind plants. This study assesses the characteristics of CTD events as observed by lidar and other offshore buoys, then evaluates the ability of modeling systems to capture the correct characteristics, leveraging model output from the High-Resolution Rapid Refresh (HRRR) operational modeling system and the NOW-23 (National Offshore Wind) model dataset. CTDs were analyzed for October 2020 and May through to October of 2021, identifying 18 unique CTD events, confirmed by a nearby National Data Buoy Center (NDBC) buoy. The HRRR model captured most of these events, but the NOW-23 model output contained only 12 events. Composites of the wind, temperature, and pressure perturbations pre-, during, and post-event demonstrated the diminishment in wind speed, particularly for the alongshore component. Although the NOW-23 model captured the alongshore wind component and pressure perturbations well, the cross-shore wind component and temperature perturbations varied substantially. When the turbulent kinetic energy deviation and wind shear was positive across all levels pre-event, the NOW-23 modeling system was less likely to capture the CTD event. In contrast, the events that were captured by the model tended to have negative wind shear aloft pre-event. Full article

Electrohydrodynamic effects can significantly alter transport processes in reacting flows, even when the plasma is weakly ionized. However, predictive modeling of such plasma–flame interactions remains challenging due to the multiscale coupling among charge transport, fluid motion, and chemical kinetics. This study presents a charge-transport closure model to investigate electrohydrodynamic influences on laminar non-premixed flames. A two-dimensional computational framework in cylindrical coordinates is used to simulate plasma-assisted methane–air diffusion flames under weak electric-field conditions representative of practical combustion environments. To represent plasma–flow coupling in a computationally feasible yet physically consistent manner, a charge-transport formulation based on the drift–diffusion approximation is employed. The model solves transport equations for representative positive and negative charge carriers coupled with Poisson’s equation for the electric potential to obtain a self-consistent electric field. This formulation assumes a weakly ionized regime for low-temperature plasma-assisted combustion, in which neutral species dominate the mass and momentum transport, while ionization chemistry is simplified and charge transport primarily influences the flow through electrohydrodynamic body forces and Joule heating. Assuming a weak electric field, the steady flamelet model is applied, in which plasma effects primarily influence scalar transport and local thermal balance rather than inducing significant bulk ionization dynamics. The governing equations are discretized using a high-order compact finite-difference scheme that provides improved resolution of steep gradients in temperature, species concentration, and space-charge density near thin reaction zones. The canonical laminar flame model configuration was validated using the established laminar methane–air diffusion flame benchmark, and steady-state spatial profiles of key transport properties were evaluated. Two-dimensional analysis identified the discharge coupling location as an important factor. The application of discharge in the fuel-air mixing region leads to a clear restructuring of the flame. When the discharge is activated, electrohydrodynamic forcing and ion-driven momentum transfer produce a highly localized, columnar flame with sharp gradients and a confined reaction zone. Compared with the baseline case, the plasma-assisted flame localizes the OH-rich reaction zone, confines the high-temperature region into a narrow column, and enhances downstream H₂O formation. Full article

This study addressed the issue of insufficient activity in CALB lipase during the catalytic synthesis of key chiral intermediates for moxifloxacin. A structure-guided protein engineering strategy was employed to systematically modify its functional domains. Through molecular dynamics simulations of CALB-I189K, multiple regions exhibiting high conformational flexibility were preliminarily identified. Subsequently, by integrating 3D structural alignment with active site pocket distance analysis, the functionally most critical region (143–146) was selected. A site-directed saturation mutation library was constructed specifically targeting this region. Building upon the previously reported CALB-I189K, a mutant I189K/L144R/A146K was ultimately obtained through high-throughput screening combined with chiral HPLC validation. This mutant maintains excellent stereoselectivity (E = 206.52) while enhancing catalytic efficiency (k_cat/Κ_m) to 273.73 min⁻¹·mM⁻¹, approximately 4.5-fold that of I189K. At a substrate concentration of 1 M, it achieves 50% conversion within 2.6 h, demonstrating kinetic resolution capabilities approaching industrial standards. Molecular simulation analysis indicates that the L144R and A146K mutations synergistically enhance catalytic performance primarily by optimizing spatial distances between catalytic residues. This study not only provides a high-performance catalyst for the efficient biosynthesis of moxifloxacin chiral intermediates but also offers new insights for enzyme rational design based on dynamic structural information. Full article

Background/Objectives: Synthetic stimulants represent the most prevalent subclass on the new psychoactive substances (NPSs) market. However, the toxicokinetic properties of M-ALPHA, a regioisomer of MDMA and N-methyl-cyclazodone a pemoline derivative, are not yet characterized. Methods: Therefore, this study investigated the metabolism of both NPSs in pooled liver S9 fraction and rat urine, characterized cytochrome P450 (CYP) kinetics and plasma protein binding (PPB), and assessed the CYP inhibition potential of M-ALPHA, using high-performance liquid chromatography coupled to high resolution tandem mass spectrometry (HPLC-HRMS/MS). Results: Four metabolites of M-ALPHA were detected including one phase I and three phase II metabolites, resulting from demethylenation followed by subsequent methylation or glucuronidation. For N-methyl-cyclazodone, one phase I metabolite formed via N-demethylation was identified. The primary enzymes involved in M-ALPHA metabolism were CYP2B6 and CYP2D6. Notably, M-ALPHA inhibited these enzymes to a strong or moderate extent, respectively. In contrast, the metabolism of N-methyl-cyclazodone was primarily mediated by CYP2A6. PPB studies indicated low-to-moderate binding for both compounds, suggesting that significant protein-binding interactions are unlikely. Conclusions: As M-ALPHA only formed metabolites that overlapped with those of MDMA, differing only by minor retention time shifts, reliable HPLC-HRMS/MS-based identification may be challenging in clinical and forensic toxicology settings as well as doping analysis. Furthermore, drug–drug interactions following polydrug use cannot be excluded for either NPS, particularly when co-ingested with other CYP substrates metabolized by the same isoforms. Full article

Driven by the demand for miniaturization, high capacitance, and enhanced reliability in high-performance multilayer ceramic capacitors (MLCCs), the continuous thinning of inner electrode layers imposes increasingly stringent requirements on the size, distribution, morphology, and dispersion of nano-nickel powders. We systematically investigate how functional additives regulate the nucleation, growth, and microstructural evolution of nano-nickel synthesized via hydrazine-driven liquid-phase reduction of nickel sulfate. The results demonstrate that the alkanolamine complexing agent (TAC) significantly refines the average particle size and morphology of the nano-nickel through coordination effects. Furthermore, inorganic sulfur salts (ISP), acting via surface adsorption to passivate growth sites and provide catalytic effects, enable a precise and continuous reduction in the average particle diameter from 330 nm down to 60 nm at a mere trace dosage of ~10⁻⁷ mol/L. Regarding dispersion optimization, highly dispersed face-centered cubic (FCC) nano-nickel was successfully prepared by introducing multidentate carboxylate (NNA). High-resolution transmission electron microscopy (HRTEM) was employed to unveil, for the first time, the crystallographic origin of the anomalous surface protrusions typically observed in conventional reaction systems. We confirmed that the family of $\left\{10\overline{1}0\right\}$ crystal planes within these regions, which exhibits interfacial angles of 58.7° and 58.3°, corresponds to a thermodynamically metastable hexagonal close-packed (HCP) nickel phase originating from atomic stacking faults induced by rapid growth kinetics. To address this microstructural defect, a thioether-based amino acid (TAA) was introduced. TAA effectively suppresses the anisotropic growth of the metastable HCP phase through the strong steric hindrance of its long side chains and its selective adsorption onto high-energy facets. Full article

Exercise adaptation and training maladaptation arise from overlapping metabolic, redox, inflammatory, endocrine, and tissue-remodeling processes, so the translational question is not whether biomarkers change but when, where, and for which decision they become informative. This narrative review develops a decision-linked framework for minimally invasive biomarkers across the recovery–overload continuum and treats biomarker meaning as a molecule–matrix–time–decision relationship rather than as a stand-alone peak. The framework is organized around five coupled layers: stimulus architecture, signaling and release biology, sampling matrix and pre-analytics, bout-relative kinetics, and the monitoring decision to be supported. Current evidence indicates that no single biomarker reliably separates productive remodeling from delayed recovery, tissue strain, non-functional overreaching, or early maladaptation. Classical chemistry remains useful for bounded tasks, especially delayed tissue strain and stress reactivity; cfDNA appears promising for rapid load sensitivity; targeted metabolite panels are strongest for recovery phenotyping; and circulating RNAs and extracellular-vesicle cargo add mechanistic depth but remain constrained by pre-analytical fragility and incomplete standardization. The central practical implication is that overload is better interpreted as progressive loss of signal resolution than as threshold-crossing and that sparse temporally staggered panels are more likely to aid monitoring decisions than isolated markers or untimed high-dimensional profiles. Progress will depend on purpose-specific panels, transparent analytical standards, and prospective validation against symptoms, performance, and established measures across sex, hormonal, circadian, and training contexts. Full article

The Temporal Analysis of Products (TAP) pulse response technique provides valuable insights into catalytic function and reaction kinetics. However, complex fragmentation patterns in the TAP mass spectrometry signals can complicate precise quantification, particularly when analyzing transient gas flux data typical of TAP experiments. This work demonstrates a standard defragmentation method that deconvolves transient TAP signals while maintaining the temporal resolution of the experiment. First, the integrals of calibration gas fluxes are used to determine the fingerprint fragmentation pattern and construct a fragmentation matrix. This matrix is then used to defragment experimental flux data at each recorded time point via a non-negative least squares regression. The effectiveness of this method is demonstrated using virtual data and control experiments with a TAP reactor system. The defragmentation is then applied to the more complex propane dehydrogenation reaction on a chromia/alumina catalyst, which can contain up to ten significant gas species in the reactor outlet. Initial propane pulsing reveals an induction period during which propane is fully oxidized to CO_2, followed by partial reduction to CO. Afterwards, there is a transition in chemistries towards coking and propylene production. Our example illustrates a practical method for the accurate determination of the time-dependent reactant/product concentrations and rates for a thorough analysis of the propane dehydrogenation kinetics. This approach can be broadly applied to any transient mass spectrometry experiment for a better understanding of catalyst-reaction dynamics. Full article

Background/Objectives: Although Drosophila melanogaster is widely used in genetics and nutrition research, developmental kinetics are rarely analyzed using formal mathematical modeling. Most dietary studies present developmental curves without rigorous fitting, limiting quantitative interpretation. This study applies and compares three primary models, as well as develops secondary models, to characterize the effects of high-sugar diets on egg-to-adult (life cycle) development. Methods: Standardized husbandry and an embryo-to-pupa feeding assay were performed across 11 sucrose concentrations. Synchronized embryo collection and high-resolution monitoring were used for this assay. Three primary models—dose–response, Gompertz, and logit-based linearization—were fitted to developmental curves to extract timing (t_mid) and synchrony (s_dvp) parameters. Secondary modeling was used to evaluate how these parameters change with respect to sucrose concentration. Results: Increasing sucrose concentration markedly delayed pupariation and reduced viability at the highest levels. All models showed increasing t_mid and decreasing s_dvp with rising sugar concentration, with the Gompertz model providing the best overall performance. Secondary modeling revealed a consistent bilinear response with a breakpoint at 0.52–0.62 M, separating low-, medium-, and high-sucrose conditions. Reduced sampling frequency decreased model robustness, while twice-daily observations remained sufficient. Conclusions: Mathematical modeling provides a robust, practical framework for quantifying the effects of diet on D. melanogaster development. The Gompertz model provided the best fit and yielded biologically interpretable parameters. The bilinear secondary model effectively captured sucrose-dependent stress responses and quantified plasticity through environment-dependent changes in developmental timing and synchrony. Overall, this work establishes a quantitative practical framework for modeling developmental kinetics under nutritional perturbations, and the approach can be extended with additional secondary environmental factors to improve predictive analyses of nutritional effects. Full article

Isothermal dispatch models for battery energy storage systems (BESSs) systematically underestimate degradation costs because dispatch-induced Joule heating elevates cell temperature and accelerates ageing through Arrhenius-type kinetics. This paper proposes three integrated contributions. First, a thermal–electrochemical coupling loop embeds a first-order lumped thermal model within the dispatch simulation: cell temperature is updated from I²R heat generation and Newton cooling at each time step, and the resulting temperature trajectory feeds into the Arrhenius stress factors of a semi-empirical degradation model combining $\sqrt{\Delta t}$-based calendar ageing with Rainflow-based cycle ageing, enabling the optimiser to discover thermally self-regulating strategies. This coupling is critical because, as the results demonstrate, ignoring it leads to systematic underestimation of degradation costs by up to 13%. Second, the resulting four-objective problem (negative profit, thermally coupled degradation cost, SOC deviation, and CVaR imbalance penalty) is solved by a hypervolume-contribution-enhanced NSGA-III (HVC-NSGA-III), which augments reference-point selection with an archive pruned by removing the solution of the smallest individual hypervolume contribution, concentrating Pareto resolution in the knee region. Third, an SOH-adaptive knee-point selection assigns the degradation weight as a monotone function of ageing degree $(1-\mathrm{SOH})/(1-{\mathrm{SOH}}_{\mathrm{EOL}})$, automatically tightening dispatch conservatism as remaining useful life diminishes. Simulations on ENTSO-E data over 96 h show the following: (i) thermal coupling shifts the Pareto front by 8–15% in the degradation dimension with temperature excursions up to 7 K; (ii) HVC-NSGA-III improves hypervolume by 8.7% over standard NSGA-III; (iii) SOH-adaptive selection reduces capacity loss by 27.4% at only 9.1% revenue cost; and (iv) ablation confirms Rainflow (24.8%) and thermal coupling (13.1%) as the two largest contributors. Full article

This study addresses challenges in fluid catalytic cracking (FCC) units, including inaccurate quantification of carbon emissions, difficulties in implementing low-carbon operational optimization, and low computational efficiency in solving complex process kinetics. A low-carbon operation optimization method based on physics-informed neural networks (PINNs) is proposed. First, a unit-level carbon footprint assessment model is established using process life cycle assessment (PLCA) to achieve high-resolution quantification of both direct and indirect carbon emissions. Second, a multi-objective low-carbon operation optimization model is developed considering carbon tax scenarios, incorporating carbon emissions and corresponding carbon tax costs into the optimization objectives to achieve economic and low-carbon synergistic optimization. Finally, a PINN-assisted surrogate model is designed by embedding material balance constraints into the neural network training process, enabling efficient approximation of complex product yield kinetics and improving optimization solution efficiency and predictive reliability. The proposed method is applied to optimize the operation of an FCC unit at a refinery site. The results indicate an increase of 12,048.851 CNY/h in profit, a reduction of 1088.921 kgCO₂eq/h in CO₂ emissions, and a decrease of 324.281 m³/h in steam consumption. Meanwhile, the PINN model exhibits excellent performance in product yield prediction, with an average $R^2$ of 0.9968 and an average RMSE of 0.1482, outperforming conventional data-driven methods. The proposed approach balances carbon emission quantification accuracy, physical consistency in yield prediction, and optimization solution efficiency, providing a systematic and implementable technical framework for low-carbon operation optimization of FCC units. Full article

Low-temperature methanation technology offers a promising pathway for carbon recycling and sustainable energy storage by enabling near-equilibrium CO₂ conversion under atmospheric pressure. However, efficiently activating CO₂ at low temperatures remains a significant challenge due to the kinetic limitations of hydrogenation intermediates. We construct a composite oxide–metal interface structure by anchoring highly dispersed CeCrO_x nanoclusters onto metallic nickel via an ion-exchange method. This catalyst exhibits superior activity compared to conventional Ni/oxide catalysts with identical composition. Under atmospheric pressure at 220 °C, it achieves nearly 80% CO₂ conversion with over 99% methane selectivity and maintains excellent catalytic performance and structural stability during a 240-h continuous test. Systematic characterizations, including high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, CO₂ temperature-programmed desorption, and in situ DRIFTS reflectance infrared Fourier-transform spectroscopy, reveal that the synergistic modification by CeO₂ and Cr₂O₃ not only optimizes the electronic structure of Ni to promote CO₂ adsorption and activation, but also enhances H₂ dissociation and intermediate conversion by regulating oxygen vacancy concentration and alkaline site distribution. Mechanistic studies indicate that the reaction follows a synergistic mechanism dominated by the formate pathway and assisted by the CO pathway. Moreover, the interfacial structure effectively stabilizes active sites and inhibits carbon deposition from CH₄ decomposition. This study provides a universal and effective strategy for designing Ni-based CO₂ conversion catalysts suited for mild reaction conditions and characterized by high energy efficiency. Full article

This study investigates the electrostatic and electrochemical behavior of polyaniline (PANI) and its composite with amine-functionalized multi-walled carbon nanotubes (PANI/MWCNT–NH₂) to elucidate the mechanisms governing ammonia (NH₃) sensing. High-resolution atomic force microscopy (AFM) coupled with electrostatic force microscopy (EFM) demonstrates that pristine PANI forms granular macroaggregates with localized charge distribution, whereas MWCNT incorporation promotes worm-like percolative networks that enhance charge delocalization and conductivity. Electrochemical characterization by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) corroborates these nanoscale observations, revealing significantly improved interfacial electron transfer kinetics in the composite. Upon exposure to NH₃, pristine PANI undergoes rapid de-doping and nonlinear signal suppression, while the composite exhibits a more progressive electrochemical modulation. Overall, the results demonstrate that NH₃ sensing in PANI-based films is governed not solely by electroactive material content but by the interplay between nanoscale morphology, electrostatic heterogeneity, and charge transport topology. The nanotube-mediated formation of delocalized and percolative conductive pathways provides structural and electrochemical robustness, enabling tunable, high-sensitivity operation suitable for next-generation, low-power ammonia sensing platforms. Full article

Background/Objectives: Eudesmin is a tetrahydrofurofuranoid lignan known for its diverse pharmacological activities, including anti-tumor, anti-inflammatory, and neuroprotective effects. However, its metabolism has not been well characterized. Methods: This study examined the in vitro metabolism of eudesmin using human and mouse hepatocytes, human liver microsomes, and recombinant drug-metabolizing enzymes. Liquid chromatography–high-resolution mass spectrometry combined with ion identity molecular networking enabled the comprehensive visualization and annotation of eudesmin metabolites. Results: Eudesmin exhibited moderate metabolic stability in human and mouse hepatocytes, with half-lives of 181.0 min and 132.9 min, and intrinsic clearance values of 27.7 mL/min/kg and 154.0 mL/min/kg, respectively. Incubation of eudesmin with human hepatocytes resulted in the formation of 13 metabolites, including five phase I metabolites (M1–M5) and eight phase II conjugates. Phase I metabolism was dominated by O-demethylation of the 3,4-dimethoxyphenyl moieties, yielding mono-O-demethylated (M1 and M2) and di-O-demethylated metabolites (M3 and M4), as well as a hydroxylated metabolite (M5). Enzyme phenotyping, kinetic analyses, and chemical inhibition experiments identified cytochrome P450 2C9 (CYP2C9) as the major contributor to O-demethylation, with additional contributions from CYP2C19, CYP2C8, CYP3A4, and CYP3A5, whereas hydroxylation was mediated primarily by CYP3A4 and CYP3A5. The O-demethylated metabolites subsequently underwent phase II metabolism, forming glucuronide conjugates of M1–M4 and sulfate conjugates of M1–M3, including a disulfate of M3. Uridine 5′-diphospho-glucuronosyltransferase and sulfotransferase screening revealed the involvement of multiple conjugative enzymes, indicating extensive and distributed phase II metabolism. Specifically, di-O-demethylated metabolites and their conjugates were detected in human hepatocytes but not in mouse hepatocytes, suggesting that the sequential O-demethylation pathway is limited in mice. Conclusions: This study characterizes eudesmin metabolism, with CYP2C9-mediated O-demethylation and significant species differences between humans and mice, and provides a basis for its further pharmaceutical development. Full article

Temozolomide and dacarbazine are untargeted anticancer prodrugs that have been widely employed in the treatment of melanoma and glioblastoma. These agents decompose into a short-lived monomethyl triazene intermediate, culminating in the release of a methyl diazonium cation that serves as the DNA-alkylating species responsible for tumour destruction. However, due to their high chemical lability, these agents have been associated with chemotherapy resistance, mutagenicity, tumour relapse, and significant off-target toxicity. One promising strategy towards the resolution of these limitations involves the design of arylmethyl triazene prodrugs, which enable targeted tumour-specific drug delivery. This review explores the various approaches used to selectively deliver alkyl aryl triazenes as alternatives to current therapies. It highlights early chemical strategies such as N-acylation and etherification of monomethyl triazenes, along with associated kinetic studies. The selective activation of novel triazenes in murine and human melanoma cells through a tyrosinase-responsive promoiety is discussed. Recent progress in nitroaromatic-based prodrugs designed to exploit the hypoxic microenvironment of glioblastoma is also examined. Additionally, we summarise the development of combi-triazenes and their underlying chemistries, which enable the simultaneous release of two active therapeutic agents. Full article

Hexagonally ordered mesoporous carbon was ozonized, and the oxidized carbonaceous material was modified with L-arginine. The ozonized and L-arginine-modified carbons were extensively characterized and tested as Pb(II) ion adsorbents, with optimization of Pb(II) solution pH, exposure time, Pb(II) ion concentration and the presence of concurrent ions. Pb(II) adsorption equilibrium was achieved within 5 min at optimal pH = 2.6 or 5.3 for the oxidized and L-arginine-modified carbonaceous materials, respectively. The adsorption kinetics of both investigated materials were best described by the pseudo-first-order model. The maximum adsorption capacity for Pb(II) ions was determined to be 16 mg g⁻¹ (ozonized material) or 45 mg g⁻¹ (L-arginine-modified material). The Langmuir model provided the best fit for the adsorption isotherm data. Fe(III) ions mostly hindered the Pb(II) adsorption (up to 60%) on the L-arginine-modified carbon material. L-arginine-modified carbon was used to enrich Pb(II) from simulated urban roof runoff and its determination using the slurry sampling high-resolution continuum-source graphite furnace atomic absorption spectrometry technique. The developed analytical procedure was characterized by a limit of quantification of 2.63 µg L⁻¹, an enrichment factor of 50, and a recovery rate of 94.8%. Full article