A sensitive HPLC method for quantitative determination of oxytetracycline and its structural analogues to support residue monitoring in disease-managed crops.

Objectives Amantadine (AMD) is an antiviral and antiparkinsonian drug with a narrow therapeutic window and a recognized risk of severe intoxication. Interpretation of postmortem drug concentrations is complicated by postmortem redistribution (PMR), yet systematic toxicokinetic and multi-tissue PMR data for amantadine remain limited. Methods An integrated investigation of amantadine toxicokinetics and postmortem redistribution was conducted in male rats. For toxicokinetic assessment, a single oral dose of 450 mg/kg (LD50) was administered, and concentrations were quantified in blood and nine tissues over a 96-h period. For the PMR study, rats received low (42 mg/kg), medium (LD50), and high (2 × LD50) doses, followed by controlled postmortem storage at 4 °C and 20 °C for up to 96 h. Amantadine concentrations were determined using validated HPLC–MS/MS methods and analyzed by pharmacokinetic and statistical approaches. Results Amantadine was rapidly absorbed and widely distributed, exhibiting pronounced tissue-specific heterogeneity. The liver and kidney showed the highest exposure, whereas accumulation in the brain and testis was limited. Postmortem redistribution was substantial and tissue dependent, and was strongly influenced by dose, postmortem interval, and storage temperature. Blood concentrations were unstable over time, while solid organs, particularly the liver and spleen, exhibited higher and more sustained postmortem concentrations. Notably, selected inter-tissue concentration ratios (e.g., liver-to-lower limb muscle and spleen-to-brain) displayed consistent, dose-dependent trends across postmortem conditions. Conclusions This study provides a comprehensive characterization of amantadine toxicokinetics and postmortem redistribution across multiple biological matrices. The findings underscore the limitations of relying solely on postmortem blood concentrations and support the complementary use of selected tissues and inter-tissue concentration ratios as comparative indicators in toxicological interpretation. These results offer mechanistic insight into postmortem drug dynamics and provide practical reference data to improve the interpretation of suspected amantadine intoxication.

This study assessed temporal variations of Total Petroleum Hydrocarbons (TPH) in water, sediment, Periwinkle (Tympanotonos fuscatus) and Oyster (Crassostrea gasar) from the Iwofe River, Niger Delta. Samples collected bimonthly from July 2018 to May 2019 were analyzed using gas chromatography. Sediment recorded consistently higher TPH concentrations than water, peaking in January (8.89 mg/kg), while water values remained low (0.01–0.02 mg/L). Oyster accumulated higher and more variable TPH levels (0.002–0.029 mg/kg) than Periwinkle (0.003–0.005 mg/kg), with significant temporal changes observed only in Oyster. Seasonal comparisons showed no significant difference for Oyster but a minor yet significant variation for Periwinkle. The overall pattern confirmed a clear accumulation hierarchy of sediment > Oyster > Periwinkle > water. These findings highlight sediments and Oysters as sensitive indicators of petroleum contamination and the importance of using multiple matrices to better understand hydrocarbon dynamics in polluted coastal ecosystems. The elevated sediment and Oyster concentrations underscore potential ecological risks and reinforce the need for continuous monitoring and improved management in oil-impacted environments such as the Niger Delta.

Data representation is a critical foundation of machine learning, as it determines how raw information is structured, stored, and transformed into mathematical forms that algorithms can process. The effectiveness of representation directly influences the accuracy, efficiency, and interpretability of models. This paper investigates the role of data representation using a student dataset as a case study. The dataset includes both numerical features, such as hours studied, attendance percentage, and exam scores, as well as categorical features, including gender and extracurricular participation. These diverse attributes provide an ideal context for demonstrating multiple representation techniques, including vectors, matrices, tensors, one-hot encoding, and dimensionality reduction. The study applies regression, classification, and neural network models to the dataset, highlighting how proper representation improves predictive performance. For example, logistic regression achieved significantly higher accuracy when categorical variables were encoded using one-hot representation compared to raw categorical labels. Principal Component Analysis (PCA) reduced dimensionality while retaining over 95% of the variance, thereby simplifying training and improving computational efficiency. Neural networks using dense embeddings further enhanced prediction accuracy, demonstrating the importance of advanced representation methods

Luffa cylindrica, a plant from the Cucurbitaceae family, is abundant but remains underutilized. Its simple fiber extraction and high cellulose content make it a potential eco-friendly reinforcement material for composites. This study examines the effect of silane concentration on the interfacial shear strength (IFSS) and wettability of Luffa cylindrica fibers. The fibers were treated with silane solutions at concentrations of 0.5%, 1%, and 1.5%. Tests included IFSS, wettability, and SEM analysis. Results show that silane treatment improves both IFSS and wettability, with the highest values obtained at 0.5% concentration (3.68 MPa and 43.94 mN/m, respectively). SEM observations confirmed better fiber–matrix adhesion at this concentration, where multiple matrices were attached and embedded on the fiber surface. These findings highlight the potential of silane-treated Luffa cylindrica fibers as effective reinforcements for composites

Development and validation of an analytical method for determining triflumezopyrim residues in multiple paddy field matrices (Paddy Water, Paddy Soil, Brown Rice, Rice Husk, and Rice Straw) using GC-ECD and GC-MS.

A comprehensive workflow for resolving Gryllidea phylogeny using universal single-copy orthologs.

Background: Emerging endocrine-disrupting chemicals (EDCs) in food pose a growing challenge to chemical food safety because they interfere with hormonal regulation. These compounds are detected in multiple food matrices and food-contact materials, including plastics and metal can coatings. Chronic exposure, even at trace concentrations, has been associated with metabolic, reproductive, and neurodevelopmental outcomes. Moreover, replacing bisphenol A (BPA) with structural analogues (BPF, BPS, BPAF) and epoxy derivatives such as BADGE has raised concerns about regrettable substitution, since several alternatives show comparable endocrine activity. Methods: A systematic review was conducted following PRISMA guidelines. Searches in PubMed, ScienceDirect, MDPI Journals, SciELO, and Frontiers identified original experimental studies on chemical detection and toxicological relevance of EDCs in foods and food-contact materials. Eligible studies applied validated analytical techniques, including LC–MS/MS, UHPLC–MS/MS, often combined with QuEChERS, SPE, or SPME. After screening and eligibility assessment, 20 experimental articles were included. Results: Most studies employed chromatography coupled to mass spectrometry, enabling trace-level quantification, frequently in the ng/kg range. Multiclass methods simultaneously determined bisphenols, phthalates, parabens, epoxy-related migrants, and non-intentionally added substances (NIAS). Bisphenols were consistently detected in processed foods, canned products, and dairy matrices. Migration was strongly influenced by packaging composition, temperature, and contact time, and endocrine-active compounds were reported even in materials labeled as BPA-free. Discussion & Conclusion: High-resolution chromatographic–spectrometric advances have strengthened EDC monitoring in food systems. However, challenges remain regarding methodological harmonization, evaluation of substitutes and NIAS, and integration of analytical results with toxicological interpretation. This supports improved health.

This research detailed a hydrochemical investigation and spatial variability examination of the groundwater quality at five principal sites in the Kano Region, Nigeria, namely Hotoro, Kano Municipal, Kumbotso, Kofar Fada, and Gezawa, with a total of Fifty-one (51) water samples collected. Physical, chemical, and biological parameters assessed in the water samples were Electrical Conductivity, Hardness, pH, Total Dissolved Solids (TDS), Temperature, Turbidity, Dissolved Oxygen (DO), major cations (Na+, K +, Mg2+, Ca2+ ), and trace metals (Cr, As, Fe, Zn, Cu, Ni, Pb, Cd). The data demonstrated a high level of spatial heterogeneity that should be considered when examining not only natural geological structures but also anthropogenic factors, particularly in urbanised and peri-urban districts of Kano and certain parts of the surroundings, where elevated Conductivity, TDS, Hardness, and several ion concentrations were observed. The pH was usually in the slightly acidic to slightly alkaline range, with low levels of Dissolved Oxygen indicating possible impacts from organic contaminants or eutrophication. Two multivariate visualisations (box plots, Scatter plots, multiple correlation matrices, PCA, and Piper diagrams) help clarify the complex correlations among the constituents of water quality. The Piper diagram revealed unique hydrochemical facies, primarily Sodium-Chloride and Calcium-Magnesium Bicarbonate, which combined the natural geochemistry of sediments with urban anthropogenic effects. The concentrations of Trace metals were generally low, with little acute risk identified, but periodic increases in iron and Zinc indicated localised areas of potential concern. The inter-area differences were strongly supported by statistical testing, indicating the need for specific water resource management approaches and pollution control strategies. The statistical testing strongly indicated an inter-area difference, necessitating specific approaches to water resources management and pollution control strategies. Overall, the synthesis of spatially resolved hydrochemical measurements with spatial data and its processing has the potential to make an essential contribution to the sustainable monitoring of water quality and environmental management in the Kano region, and to support sound decisions to preserve the health of the overall population and water bodies. In general, the combination of spatially addressed hydrochemical observations with spatial data and its analysis presents an opportunity for a crucial contribution to sustainable monitoring of water quality and environmental management in the Kano area, and to rational decisions to preserve the health of the general population and aquatic ecosystems.

We analyze a varying-coefficient spatial autoregressive model with spatial fixed effects. One salient feature of the model is the incorporation of multiple spatial weight matrices through their linear combinations with varying coefficients, which help solve the problem of choosing the most “correct” one for applied econometricians who often face the availability of multiple expert spatial weight matrices. We estimate and make inferences on the model coefficients and coefficients in basis expansions of the varying coefficients through penalized estimations, establishing the oracle properties of the estimators and the consistency of the overall estimated spatial weight matrix, which can be time-dependent. We further consider two applications of our model in change point detections in spatial autoregressive models, providing theoretical justifications in consistent change point locations estimation and practical implementations. Simulation experiments demonstrate the performance of our proposed methodology, and real data analyses are also carried out.

N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6-PPD), a tire rubber antioxidant, and its oxidation product 6-PPD-quinone (6-PPDQ) have raised environmental and health concerns due to their widespread occurrence and toxicity. This study aimed to develop and validate a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of 6-PPD and 6-PPDQ in murine tissues. The method showed excellent linearity (r ≥ 0.9977), low detection limits (0.056-0.967 ng/mL), and high accuracy and precision across multiple tissue matrices, enabling reliable quantification at trace levels. Following repeated intratracheal administration in mice, both analytes were detected in the liver, lungs, and kidneys, but not in the spleen. Notably, 6-PPDQ exhibited marked dose-dependent accumulation in the lungs, whereas 6-PPD remained at low levels, suggesting strong pulmonary retention. In contrast, trace levels of 6-PPD and a dose-dependent increase in 6-PPDQ were found in the kidneys, indicating renal elimination as a clearance route. These results reveal selective organ distribution, with the lung as the primary deposition site, and highlight 6-PPDQ as a potential multi-organ toxicant. The validated LC-MS/MS method provides a valuable analytical platform for future toxicokinetic, biomonitoring, and mechanistic studies of tire-derived contaminants.

The co-design problem of dual event-triggered (DET) mechanism and polynomial dynamic output-feedback (PDOF) controller is investigated for positive polynomial fuzzy systems (PPFSs) with uncertainty and disturbance constraints. Specifically, a 1-norm DET mechanism compatible with the positivity of PPFSs is proposed to asynchronously update measurement outputs and PDOF control signals. However, synthesizing this DET-PDOF controller proves challenging due to the coupling of multiple unknown PDOF controller gain matrices within the positivity and stability conditions, which results in complex nonconvex terms. By introducing auxiliary variables and constraints, sufficient conditions for DET-PDOF controller solution are given to ensure both the $L_{1}$ -gain performance and strict positivity of PPFSs with uncertainty and disturbance. Moreover, existing stability analysis results that ignore membership functions (MFs) tend to be conservative, implying that the obtained DET-PDOF controller is effective only within a limited triggered threshold range, leading to worse transmission performance. Therefore, a multivariate optimization method based on an improved genetic algorithm (IGA), which accounts for the system states and PDOF controller variables, is developed to substantially expand the admissible DET threshold range while effectively suppressing dual-triggering frequencies. Finally, a numerical example and a two-linked tank system with parameter uncertainty are provided to validate the feasibility of the proposed scheme.

Abstract Whilst molecular methods for plant virus detection are usually based on PCR amplification, loop mediated isothermal amplification (LAMP) is a rapid and sensitive molecular diagnostic tool increasingly used for plant virus detection, particularly in field conditions and resource-limited laboratories. In this study, a novel LAMP primer set (ID: 334) was developed for the specific detection of Potato virus Y (PVY), a globally significant pathogen responsible for yield losses of up to 80% in potatoes. Primer set 334 was designed based on conserved regions identified across 30 complete PVY genomes. It was evaluated against 33 PVY isolates representing 5 strain groups. The assay demonstrated 100% inclusivity, successfully detecting all isolates, including both recombinant and non-recombinant strains. Specificity testing confirmed no cross amplification with related potyviruses (Potato virus A (PVA) and Potato virus V (PVV)) or unrelated potato viruses (Potato virus X (PVX), Potato leafroll virus (PLRV), and Potato mop-top virus (PMTV)), further validating the exclusiveness of the assay. Moreover, the assay was validated on multiple host matrices, including leaves and tuber tissues of potato. Compared to a previously published LAMP assay, primer set 334 exhibited 2.6-fold greater sensitivity, detecting PVY at four orders of magnitude lower concentrations, with performance comparable to qPCR but with faster time-to-result. This improved LAMP assay provides a rapid, specific, and sensitive tool for PVY detection in leaves and tubers, supporting both laboratory, field, and post-harvest diagnostics.

This article considers matrix multiplication in the problem of finding the transitive closure of a binary relation with the transitivity property, as well as in the construction of the reachability and counter-reachability matrices in general graphs. An analysis of approaches to practical implementation for finding the transitive closure of a binary relation is presented: the Floyd-Warshall algorithm and raising the adjacency matrix to a power until it stabilises. The problem of processing large (thousands to millions of elements) graph diagrams of parallel algorithms on a processor (CPU), and the primary methods for optimising matrix calculations at both the software (algorithmic) and hardware levels, are considered. The main types of digital devices based on the parallel-pipeline data-processing principle are identified, and their advantages and disadvantages are outlined. A specialised computing device for fast multiplication of square binary matrices of size n × n is considered, whose distinctive feature is pipelining the data read operation from a specialised multiport memory. A mathematical model and a method for organising the parallel-pipeline memory of a specialised square binary matrix multiplication device are presented. An estimate of the matrix-processing time and hardware complexity for the developed and prototype devices is presented. Computational experiments showed that, despite a slightly higher hardware complexity (up to 8.8×) than the prototype device, the proposed device multiplies square binary matrices of size n ≤ 512 up to 52.4× faster. This represents a significant advantage when implemented in a semi-custom design using field-programmable gate arrays or a custom design based on application-specific integrated circuits. In this paper, we present a novel systolic device whose core innovation is a pipelined multiport memory architecture. By ensuring a continuous, high-bandwidth data flow to the processing elements, our contribution enables the systolic array to operate at its theoretical peak performance.

Engineering Fe-doped carbon-based nanozyme from novel source for chemiluminescence/colorimetric dual-mode microplate sensing of the anticancer drug raloxifene in different matrices.

Eigenvalue bounds for preconditioned symmetric multiple saddle-point matrices

Abstract Typhlocybinae is one of the most diverse groups of leafhoppers, constituting an important component of phytophagous insect diversity. The traditional tribal‐level phylogenetic relationships within this subfamily remain contentious, with differing hypotheses implying distinct evolutionary histories. This study contributes to resolving these controversies using phylogenomics. We newly sequenced low‐coverage whole genomes for 54 species spanning the six classic tribes of Typhlocybinae. From these data, we extracted thousands of universal single‐copy orthologs (USCOs) and ultraconserved elements (UCEs). Robust tribal‐level phylogenies were reconstructed using multiple dataset matrices (USCO50, USCO70, USCO90, USCO_fna, ClipKIT_USCO70, UCE_fna) and tree‐building strategies, including partitioned maximum likelihood with homogeneous models, unpartitioned heterogeneous mixture models and the multi‐species coalescent (MSC) model. A particular focus was placed on elucidating the complex taxonomic status between Zyginellini and Typhlocybini, integrating molecular results with morphological evidence. Our findings indicate that the choice of molecular marker type and modelling methods can influence the inferred tribal‐level relationships. Data filtering improves tribal‐level support. The final analyses reveal that Zyginellini is not monophyletic but is intermixed with Typhlocybini, although some Zyginellini lineages appear to have originated earlier than the Old World Typhlocybini. The other four tribes of Typhlocybinae are all monophyletic. The tribal‐level phylogenetic relationship is: ((Zyginellini_Typhlocybini) + (Dikraneurini + Erythroneurini)) + (Alebrini + Empoascini). Furthermore, integrating wing venation morphology with previous molecular evidence, we propose the Eualebrina subtribe nov. of Typhlocybini (sensu lato). This study provides unprecedented genomic‐scale data for Typhlocybinae and offers a framework to address similar phylogenetic challenges in other organisms.

Constructing atomically dispersed Fe-anchored Nanoislands on nitrogen-doped carbon catalysts for synergistic enhancing Fenton-like reaction dominated by singlet oxygen and high-valent metal‑oxygen species.

In this article, a robust adaptive tracking control scheme is developed for fully actuated systems (FASs) in the presence of nonlinear uncertainties, input disturbances, and multiplicative input matrices perturbation, capable of achieving the adjustable transient and steady-state performance. In comparison with the conventional and finite-time prescribed performance control (PPC) methods subject to the initial value constraint, the proposed prescribed-time PPC scheme blends the FAS approach with the speed transformation, guaranteeing the full-state asymptotic tracking with prescribed-time prescribed performance. First, a basic fully actuated controller is introduced, yielding a closed-loop tracking error system with a linear dominant part. Second, the speed transformation is applied to the closed-loop system, converting the initial PPC problem into the asymptotic convergence problem of the transferred error system and completely eliminating the initial value constraint. Third, the auxiliary control input and adaptive law embedded with positive integrable time-varying functions are devised, ensuring the boundedness of all closed-loop signals and the desired performance. Simulation studies are conducted to demonstrate the effectiveness and superiority of the presented control strategy.

Differential associations of PFAS in follicular fluid and serum with reproductive hormones: Insights from a Chinese IVF cohort GIVES.