Search Results (1,548)

Dopamine is a key neurotransmitter and neuromodulator that regulates many critical brain functions. Accurate monitoring of its level is essential for neuroscience as well as the diagnosis and treatment of many brain diseases. In this work, we developed a new electrochemical sensor, comprising phosphorus-doped graphitic carbon nitride (P-g-C₃N₄) and zeolitic imidazolate framework 67 (ZIF-67), for dopamine detection. In this composite electrode material, ZIF-67 provides numerous adsorption and sensing sites, while P-g-C₃N₄ enhances overall electrical conductivity and stability. Cyclic voltammetry tests reveal the redox behavior of dopamine at the surface of the composite electrode across various pH values and scan rates. Using differential pulse voltammetry, the sensitivity and selectivity of this dopamine sensor were assessed, identifying a limit of detection of 0.39 nM. Further successful quantification of dopamine in urine samples suggests the potential practical use of this new composite electrochemical sensor for detecting dopamine and/or other neurotransmitters. Full article

Planar microwave (MW) sensors offer high-resolution, non-invasive technology for monitoring critical soil properties, serving as a support for modern precision agriculture. While laboratory studies confirm their exceptional sensitivity, the widespread adoption of these sensors is severely impeded by critical translational challenges that constitute a defining “lab-to-field gap”. These barriers include high sensor-to-sensor variability, debilitating thermal cross-sensitivity, soil heterogeneity necessitating unique site-specific calibration, and the enduring tension between high-performance and cost-effective scaling. This review systematically synthesizes the current state of planar permittivity MW technology, moving beyond technical mechanisms to critically assess these operational limitations. We detail advanced architectural strategies designed to bridge this gap, focusing particularly on the transition toward more robust solutions. The key strategies analyzed include the adoption of differential sensor designs using microstrip patch antennas to mitigate common-mode environmental errors, the integration of ultra-compact metamaterial structures such as split-ring resonators (SRRs) and complementary split-ring resonators (CSRRs) for enhanced field robustness and deep soil sensing, and the necessity of multi-parameter sensing capabilities (moisture, pH, and salinity). By establishing a comprehensive roadmap that prioritizes field stability, cost efficiency, and seamless IoT integration, this review demonstrates that planar MW sensors are poised to become reliable and scalable tools. Addressing these critical translational hurdles will ensure optimal resource management, significantly enhance crop productivity, and enable sustainable practices within smart farming ecosystems. Full article

Polarimetric high-resolution range profiles (HRRPs) contain rich amplitude and phase information scattered from targets, making them essential for radar remote sensing applications. However, current HRRP imaging methods still face challenges in achieving precise full-polarization measurements. In addition, they are either affected by off-grid errors thus introducing spurious scattering centers (SCs), fail to utilize polarimetric priors from the channels, or encounter high computational complexity. Some of these issues limit the quality of polarimetric HRRPs, while others result in excessive computational load, hindering their application on orbital remote sensing platforms. This paper proposes a fast gridless polarimetric HRRP imaging method. First, we introduce the novel virtual full polarization sparse stepped-frequency waveforms (VFP-SSFW) to improve channel isolation, in which each pulse is transmitted with either horizontal (H) or vertical (V) polarization, selected uniformly at random. Then, we propose a polarimetric atomic norm minimization (P-ANM)-based imaging framework formulated within distributed compressed sensing (DCS), which fully exploits the joint sparsity across polarization channels while inherently eliminating off-grid errors. Additionally, we develop a fast algorithm based on alternating direction method of multipliers (ADMM) to enable efficient implementation. The proposed method can circumvent transmission channel crosstalk and can efficiently yield high-quality polarimetric HRRPs with co-registered SCs . The validity of the proposed method is demonstrated through simulated, electromagnetic, and measured experimental results. Full article

Carbon quantum dots (CQDs) and stimuli-responsive hydrogels are advanced functional materials whose hybridization yields CQD-enhanced stimuli-sensitive hydrogels, opening new interdisciplinary avenues for smart material applications. This review systematically summarizes the latest advances in these composites, focusing on synthetic strategies, structure–property modulation mechanisms, and practical applications. Distinct from existing reviews that either investigate CQDs or hydrogels independently or discuss their composites in a single research field, this work features core novelties in integration strategy, application scope and critical analysis: it systematically compares the advantages, limitations and applicable scenarios of three typical CQD–hydrogel integration approaches (physical entrapment, in situ synthesis, covalent conjugation), comprehensively covers the multi-field application progress of the composites and conducts in-depth cross-field analysis of their common scientific issues and technical bottlenecks. By incorporating CQDs, the composites achieve remarkable performance optimizations: 40% improved mechanical toughness, sub-ppm-level heavy metal-sensing sensitivity, and over 80% organic dye photocatalytic degradation efficiency, addressing pure hydrogels’ inherent limitations of insufficient strength and single functionality. These enhancements enable sophisticated applications in biomedical field (real-time biosensing, controlled drug delivery), environmental remediation (pollutant detection/degradation), energy storage, and flexible electronics. The synergistic interplay between CQDs and hydrogels facilitates precise single/multi-stimulus responsiveness (pH, temperature, light), a pivotal advance for precision medicine and intelligent environmental monitoring. Despite promising progress, the large-scale practical application of CQD–hydrogel composites still faces prominent challenges: the difficulty in scalable fabrication with the uniform dispersion of CQDs in hydrogel matrices, poor long-term stability of most composites under physiological cyclic stress (service life < 6 months in practical tests), and low accuracy in discriminating multi-stimuli in complex real-world matrices. Future research should prioritize biomass-based eco-friendly CQD synthesis, machine learning-aided multimodal responsive systems, and 3D bioprinting for scalable manufacturing. Full article

The development of effective fluorescent probes for the detection of acids and bases, both in solution and in the solid state, is of particular interest worldwide, due to the possibility of preventing hazardous consequences for human health and the environment. In the present work, the synthesis of a 1,8-naphthalimide derivative, designed as a “fluorophore-receptor₁-spacer-receptor₂” model, is considered. The compound contains two receptors for analytes in one molecule and can operate as a fluorescent probe via PET and ICT mechanisms. The photophysical behavior of the synthesized derivative in solution, on strip paper, and in thin film was investigated. It was found that the transition from acidic to alkaline medium in solution is associated with a change in color that is visible with the naked eye (yellow–orange-red–blue). The change in fluorescence, both in solution and spread on a supporting surface (strip paper and thin film), can be spectrophotometrically observed. The influence of various volatile acids on the sensing activity of the synthesized compound in solution and deposited on a solid support was investigated. It was found that with increasing acid strength, the fluorescence intensity increases. The strip paper and thin film obtained with the synthesized compound show reversible switching between the “off” and “on” states of fluorescence. The strip paper exhibited good cycling under acid–base vapor stimulation. The results obtained demonstrate the possibility of application of the synthesized compound as a colorimetric and fluorescent probe for determination of pH in solution, and detection of acids, bases, and their vapors in indoor and outdoor residential and industrial premises, as well as in the environment. Full article

A high-fat (HF) diet disrupts metabolic homeostasis and impairs peripheral circadian rhythms in key metabolic tissues. β-Hydroxybutyrate (BHB), a major circulating ketone body, functions not only as an energy substrate but also as a signaling metabolite regulating nutrient-sensing and inflammatory pathways. However, its role in modulating metabolic–circadian interactions under conditions of nutrient excess remains unclear. In this study, we investigated whether BHB supplementation influences metabolic signaling and circadian clock oscillations in liver, skeletal muscle and adipose tissue under chow and HF conditions. Male C57BL/6 mice were fed chow or HF with or without BHB supplementation (500 mg/kg body weight in the diet) for 7 weeks. Metabolic parameters were assessed by indirect calorimetry, and tissues were collected every 4 h across the circadian cycle. HF feeding increased body weight and adiposity (p < 0.01), reduced AMPK activation, enhanced AKT/mTOR signaling, elevated NF-κB levels and dampened clock gene rhythmicity. BHB supplementation significantly decreased food intake in HF-fed mice (p < 0.01) and partially reversed several molecular alterations in a tissue-specific manner. In skeletal muscle and adipose tissue, BHB increased AMPK activation and reduced mTOR and NF-κB signaling (p < 0.05), whereas hepatic effects were more modest. Notably, BHB modulated circadian gene expression, restoring aspects of rhythmic amplitude and/or phase, particularly in adipose tissue. These findings may indicate that BHB supplementation modulates nutrient-sensing pathways and partially restores peripheral circadian rhythms under HF conditions. While some effects may be influenced by reduced energy intake, BHB may serve as a metabolic signal linking nutrient status to circadian regulation. Full article

Owing to the high stability and low cost of nanozymes, they have been extensively investigated and reported. In this work, highly active CeO₂ nanoflowers were first prepared and then different metal elements were doped into the CeO₂ nanoflower matrix via a novel synthesis method to fabricate M-CeO₂ (M = Cu, Fe, Co, Mn, La) nanomaterials. Mn-CeO₂ with the highest peroxidase-like activity was selected via systematic screening, the as-prepared Mn-CeO₂ nanocomposites exhibited enhanced enzyme-like activity due to the strong metal-support interaction. This article explored the effects of doping ratio, pH, temperature, reaction time, and material concentration on its activity. A simple sensitive and selective colorimetric method was established and successfully used to detect hydrogen peroxide and ascorbic acid sensitively. When the hydrogen peroxide (H₂O₂) concentration is within the 2.0–120.0 μM range, the UV-visible absorbance at 652 nm was associated linearly with the H₂O₂ concentration, R² = 0.9959, LOD = 1.7 μM (S/N = 3). The absorbance of the reaction system showed a good linear relationship with the ascorbic acid (AA) concentration (1.0–40.0 μM, R² = 0.992), LOD = 0.98 μM (S/N = 3). This study provides an effective way to construct efficient nanozymes and their potential applications in sensing and detection. Full article

Plant architecture-related traits are key agronomic traits affecting crop growth and yield. To unravel the genetic architecture of plant height (PH), ear height (EH), tassel length (TL), and tassel primary branch number (TPBN), 379 DH lines derived from 21 maize hybrids were used for genome-wide association study (GWAS) and genomic selection (GS) analyses. Although plant architecture-related traits were significantly influenced by genotype and genotype-by-environment interactions, moderate to high broad-sense heritability was observed for PH (81.3%), EH (79.6%), TL (86.4%), and TPBN (82.5%). Using six different models for GWAS, seven unique SNPs on chromosomes 1, 2, and 3 were identified for PH, 92 unique SNPs located on chromosomes 1 to 9 were identified for EH, three unique SNPs on chromosome 6 were detected for TL, and 18 unique SNPs located on chromosomes 1, 4, 5, 8, and 10 were identified for TPBN at the p-value threshold of 7.42 × 10⁻⁶. A few hotspot genomic regions conferring plant architecture-related traits were identified, located in bins 2.07, 4.07, 8.03, 6.01, and 10.00. A total of 144 putative candidate genes were identified, which were enriched in endocytosis and lipid biosynthetic process, electron carrier activity, chloroplast stroma, and plastid stroma. The prediction accuracy evaluated through 5-fold cross-validation was 0.44 for PH, 0.43 for EH, 0.31 for TL, and 0.30 for TPBN. When the training population size (TPS) reached 60–70% or marker density (MD) reached 3000, the prediction accuracy tends to stabilize, indicating that the optimum size of TPS and MD were 60–70% and 3000 for GS, respectively. The highest prediction accuracy evaluated by using 30–5000 significant SNPs corresponding to the lowest p-value was 0.70 for PH, 0.85 for EH, 0.58 for TL, and 0.75 for TPBN, with an increase in accuracy of 59.1% to 150.0%. These results demonstrate that integrating GS with a subset of highly significant SNPs can substantially enhance prediction efficiency, thereby facilitating the selection of superior genotypes and accelerating the breeding of maize varieties with optimized plant architecture. This study has further elucidated the genetic basis of maize architecture-related traits and provided valuable information on how to implement GS to breed novel maize varieties with optimized plant types. Full article

Recent evidence suggests that Helicobacter pylori can act outside stomach by influencing the gut microbiome. We hypothesize that interactions between H. pylori and the gut microbiome, and the resulting changes in the gut chemicals (bile acids and bacterial signaling molecules involved in quorum sensing, e.g., autoinducer-2/AI-2), influence pathogen survival, antibiotic response, and disease progression. Our gut microbiome, bile acid, and AI-2 analyses showed that H. pylori patients had decreased alpha diversity (p = 0.05), increased AI-2 concentration (p = 0.019), decreased taurine-conjugated bile acids, and increased unconjugated bile acids. A co-occurring module of Prevotella, Holdemanella, and Subdoligranulum, was higher in patients (p = 0.04) and relative abundance of Allisonella was positively associated with levels of unconjugated bile acids, chenodeoxycholic acid, and cholic acid (p = 0.05 and 0.02, respectively). Our study is the first to characterize the gut microbiome-metabolome signature (bile acids and AI-2) in H. pylori patients. Abundance of certain bacteria that deconjugate bile acids along with increased AI-2 possibly gives selective advantage for H. pylori growth, further reducing microbial diversity. Taurine-conjugated bile acids inhibit H. pylori growth. We propose a model describing interplay of these factors in H. pylori disease progression, suggesting therapeutic targets worth exploring with rising antibiotic resistance. Full article

Unpolluted water, both freshwater and saltwater, is essential for achieving several United Nations Sustainable Development Goals, particularly SDGs 6, 3, 2, 14, and 15. This study maps emerging water-quality monitoring technologies at intermediate technological readiness levels (TRLs 4–5) and their potential patent markets (TRL 9). A total of 40,469 patent families were retrieved from the Espacenet worldwide database using IPC G01N33/18 and used to analyze sensing parameters. A subset of 2146 water-pollution-related patents was analyzed in detail. The analysis covered sensing parameters, temporal trends, compound annual growth rates (CAGR), legal status, geographic distribution of patent origins and markets, and the technological landscape, including application domains and niche clusters. The results show pronounced exponential growth in patent filings since 2014 and a high share of active documents, indicating sustained global investment. Innovation leadership is concentrated in China, South Korea, India, the United States, and Japan, with export-oriented patents largely held by transnational corporations, while African participation remains limited. Technological trends prioritize multiparameter environmental and biological sensing, addressing pH, temperature, turbidity, dissolved oxygen, nutrients, heavy metals, polycyclic aromatic hydrocarbons (PAHs), and oxidation–reduction potential. Emerging solutions integrate autonomous platforms, remote sensing, Internet-of-Things architectures, and machine-learning-based analytics. Persistent bottlenecks include sensor robustness in harsh aquatic environments and the reliable discrimination between background variability and early pollution signals. Strengthening low-cost and scalable deployment remains essential to ensure water quality, support environmental sustainability, and minimize risks. Full article

Responsive photonic crystals, as a class of intelligent photonic materials that can generate optical signals in response to external stimuli including temperature, pH, humidity, electric fields, magnetic fields, and specific molecules, exhibit great application potential in sensing and detection, drug delivery, environmental monitoring, and other fields. This is attributed to their unique tunable photonic band gaps and visual sensing characteristics. In this paper, we systematically review the main preparation methods, including the sol–gel method, photolithography, electrochemical deposition, self-assembly, and 3D printing, and compare the advantages and limitations of each method in terms of key performance indicators, cost, applicable material systems, and scalability for large-scale production. The design strategies of photonic crystals based on different response mechanisms are discussed in detail, revealing the structure–activity relationship between external stimuli and the modulation of photonic band gaps. Meanwhile, the typical applications of responsive photonic crystals in the sensing field are comprehensively summarized, with an emphasis on the latest advances in biomedical sensing, environmental monitoring, and intelligent detection. Finally, in view of the current challenges facing responsive photonic crystals, future development directions are prospected, which provides a reference for promoting the translation of responsive photonic crystals from laboratory research to industrial applications. Full article

Siderophores are high-affinity iron-chelating metabolites that underpin microbial survival in iron-limited environments and play central roles in metal homeostasis, ecological competition, and pathogenesis. Traditionally viewed as dedicated Fe(III) scavengers, siderophores are now recognized as structurally and functionally versatile coordination agents whose donor-set architectures—particularly catecholate and α-hydroxycarboxylate motifs—permit conditional interactions beyond iron. In iron- and boron-rich niches, especially marine and mildly alkaline systems where borate availability increases, certain siderophores are chemically capable of forming reversible borate complexes through cis-diol coordination. Although Fe(III) exhibits substantially higher thermodynamic affinity and remains the primary biological target, boron binding represents a predictable secondary property arising from shared oxygen-donor chemistry. This dynamic interplay allows siderophores to cycle between iron-bound, boron-bound, and apo states depending on local redox conditions, pH, and metal availability. Here, we synthesize current knowledge on the structural classes of microbial siderophores, their transport and regulatory mechanisms, and emerging evidence for boron coordination within catecholate and carboxylate systems. By integrating coordination chemistry with microbial ecology, we propose an expanded model in which siderophores function not only as iron acquisition molecules but also as modulators of boron speciation and environmental sensing. This functional plasticity positions siderophores at the intersection of iron and boron biogeochemical cycles and highlights new directions for understanding microbial adaptation in complex metal-rich environments. Full article

Background/Objectives: Plant architecture is a critical determinant of high-density tolerance and yield potential in maize (Zea mays L.), yet the genetic networks orchestrating these complex traits require deeper elucidation. Methods: In this study, we utilized a Multi-parent Advanced Generation Inter-cross (MAGIC) population comprising 935 recombinant inbred lines (RILs) derived from 16 diverse elite founders. A comprehensive phenotypic characterization of six pivotal architectural traits—plant height (PH), ear height (EH), ear leaf length (LL), ear leaf width (LW), tassel main axis length (TL), and tassel branch number (TBN)—was conducted across three distinct agro-ecological environments. Results: Phenotypic analysis revealed substantial natural variation and high broad-sense heritability (H² ranging from 60% to 86%), with TBN exhibiting the most pronounced variability. Correlation architecture demonstrated a strong coupling between vertical growth traits (PH and EH, r = 0.73), while lateral leaf expansion (LW) and tassel complexity (TBN) showed significant genetic independence. Using a mixed linear model (MLM) for genome-wide association studies (GWAS), we identified 21 significant SNP–trait associations, including distinct chromosomal clusters on chromosome 8 for EH and chromosome 7 for TBN. By integrating genomic intervals with tissue-specific expression profiling, 23 core candidate genes were prioritized. Notably, Zm00001d042528 (FAS1), involved in chromatin assembly, was implicated in modulating meristematic cell division for plant stature. Other key regulators included Zm00001d020537 (O5) and Zm00001d025360 (F-box protein), which were associated with reproductive organ development and leaf elongation, respectively. Conclusions: These results indicate that maize plant architecture is regulated by a modular genetic framework, with specific loci independently regulating canopy structure and source–sink components. It should be noted that the findings of this study are based solely on statistical models identifying significant associations between genetic loci and phenotypes; the biological regulatory functions of the candidate genes have not yet been experimentally validated. Nevertheless, this study provides new insights into the molecular mechanisms underlying maize morphogenesis and lays a solid theoretical foundation for molecular design breeding aimed at developing high-yielding varieties tolerant of high planting densities. Full article

Soil salinity and nutrient availability are major constraints affecting crop productivity, soil quality, and agroecosystem sustainability, particularly in coastal regions vulnerable to seawater intrusion. This study provides a comprehensive spatial and temporal assessment of soil properties and quality dynamics on Hainan Island by integrating field observations and multi-temporal remote sensing (RS) datasets. In 2024, a total of 152 sampling sites were surveyed, with three topsoil soil samples collected at each location. Multi-year RS data (2024–2021), including soil salinity reflectance indices (SRSI and SI), the Normalized Difference Vegetation Index (NDVI), and land use and land cover (LULC), were analyzed to evaluate temporal and spatial variability. The soil fertility index was calculated using alkali-hydrolyzed nitrogen (AN), available phosphorus (AP), available potassium (AK), soil pH, and soil organic matter (SOM). The soil quality index was calculated using the same parameters with the addition of chromium (Cr) to account for potential heavy metal contamination. Furthermore, in this study the Inverse Distance Weighting (IDW) method was used for spatial distribution maps of soil properties and other indices. The results indicated that soils were predominantly acidic (pH < 6.0) with generally low electrical conductivity (0.01–0.53 mS cm⁻¹) across inland areas, whereas higher salinity levels (2.28–5.31 mS cm⁻¹) were observed in southern and eastern coastal zones, suggesting potential seawater intrusion. Nutrient concentrations ranged from 60.1 to 150 mg kg⁻¹ (AN), 4 to 332 mg kg⁻¹ (AP), and 50.1 to 100 mg kg⁻¹ (AK). NDVI values (0.70–0.94) indicated high vegetation density over most agricultural landscapes. Significant positive correlations were observed between soil EC and the SRSI (r = 0.781) and SI (r = 0.663; p < 0.01), demonstrating the reliability of RS-derived indices for salinity assessment. The integrated indicator-based framework developed in this study provides a scientific basis for precision agriculture, soil health monitoring, and sustainable land management in coastal agroecosystems. Full article

The use of agro-industrial waste to obtain biochar has emerged as an environmentally friendly, low-cost, effective, profitable, and sustainable strategy for the removal of aflatoxin B1 (AFB1), a highly toxic and carcinogenic mycotoxin of importance in poultry production systems because it can cause serious economic losses, affect hatchability, egg production, and the growth of birds, and can cause their death. In this sense, the objective of the present study was to obtain a sustainable and low-cost biochar derived from agro-industrial coconut shell waste (BCS) and evaluate its AFB1 adsorption capacity using a conventional method based on buffer solutions and an in vitro avian digestion model that simulates the conditions of the gastrointestinal tract of the broiler chicken. The results showed that the adsorption capacity of BCS on AFB1 (250 ng/mL) at both pH 5.0 and 1.2 was close to 100%, while at pH 6.8, the adsorption of AFB1 was 86.24%. However, in the in vitro avian digestibility model, the adsorption capacity of BSC on AFB1 was 32.96%, thus highlighting the importance of considering factors that can affect the adsorption capacity of materials before in vivo studies, as this can lead to overestimations of results and, therefore, ineffective treatments or unexpected results in animals. Full article