Search Results (7,172)

Donor–π–acceptor (D–π–A) dyes have garnered significant attention due to their unique optical properties and potential applications in various fields, including optoelectronics, chemical sensing and bioimaging. This study presents the design, synthesis, and comprehensive photophysical investigation of a series of ionic dyes incorporating five- and six-membered heterocyclic rings as electron-donating and electron-withdrawing units, respectively. The influence of the dye structure, i.e., (a) the systematically varied heteroatom (NMe, S and O) in donor moiety, (b) benzannulation of the acceptor part and (c) position of the donor vs. acceptor, on the photophysical properties was evaluated by steady-state and time-resolved spectroscopy across solvents of varying polarity. To probe solvatochromic behavior, the Reichardt parameters and the Catalán four-parameter scale, including polarizability (SP), dipolarity (SdP), acidity (SA) and basicity (SB) parameters, were applied. Emission dynamics were further analyzed through time-resolved fluorescence spectroscopy employing multi-exponential decay models to accurately describe fluorescence lifetimes. Time-dependent density functional theory (TDDFT) calculations supported the experimental findings by elucidating electronic structures, charge-transfer character, and dipole moments in the ground and excited states. The experimental results show the introduction of O or S instead of NMe causes substantial hypsochromic shifts in the absorption and emission bands. Benzannulation enhances the photoinduced charge transfer and causes red-shifted absorption spectra to be obtained without deteriorating the emission properties. Hence, by introducing an appropriate modification, it is possible to design materials with tunable photophysical properties for practical applications, e.g., in opto-electronics or sensing. Full article

Fast and precise monitoring of soil organic matter (SOM) during maize growth periods is crucial for real-time assessment of soil quality. However, the big challenge we usually face is that many agricultural soils are covered by crops or snow, and the bare soil period is short, which makes reliable SOM prediction complex and difficult. In this study, an unmanned aerial vehicle (UAV) was utilized to acquire multi-temporal hyperspectral images of maize across the key growth stages at the field scale. The auxiliary predictors, such as spectral indices (I), field management (F), plant characteristics (V), and soil properties (S), were also introduced. We used stepwise multiple linear regression, partial least squares regression (PLSR), random forest (RF) regression, and XGBoost regression models for SOM prediction, and the results show the following: (1) Multi-temporal remote sensing information combined with multi-source predictors and their combinations can accurately estimate SOM content across the key growth periods. The best-fitting model depended on the types of models and predictors selected. With the I + F + V + S predictor combination, the best SOM prediction was achieved by using the XGBoost model (R² = 0.72, RMSE = 0.27%, nRMSE = 0.16%) in the R3 stage. (2) The relative importance of soil properties, spectral indices, plant characteristics, and field management was 55.36%, 26.09%, 9.69%, and 8.86%, respectively, for the multiple periods combination. Here, this approach can overcome the impact of the crop cover condition by using multi-temporal UAV hyperspectral images combined with valuable auxiliary variables. This study can also improve the field-scale farmland soil properties assessment and mapping accuracy, which will aid in soil carbon sequestration and soil management. Full article

Background: The Tibetan Plateau, which is known for its high elevation and low oxygen levels, presents a challenging environment for its inhabitants. To adapt to these hypoxic conditions, species of Schizothoracine, a subfamily of Cyprinidae, have developed unique physiological mechanisms and functions. Transforming growth factor-β (TGF-β) is a multifunctional cytokine involved in the regulation of cell growth, differentiation, apoptosis, and the cellular immune response. However, its specific role in adaptation to hypoxia remains poorly understood. Methods: In this study, we aimed to characterize the TGF-β1 gene in Gymnocypris dobula (Gd) and Schizothorax prenanti (Sp) and to test whether TGF-β1 contributes to hypoxia adaptation in plateau Schizothoracine fish. The predicted protein for Gd-TGF-β1 contains several primary domains, including cwf21 (cdc5 protein 21), GYF (Glycine-Tyrosine-Phenylalanine), FN1 (Fibronectin 1), a conservative domain, and a signal peptide. Results: The results of tissue distribution revealed that the mRNA level of TGF-β1 in brain, heart, muscle, skin, gills, and spleen—which are key tissues involved in oxygen sensing, transport, and physiological adaptation to hypoxic environments—was significantly lower in G. dobula than that in S. prenanti. Western blotting analysis revealed that the expression of activated TGF-β1 in G. dobula was significantly higher than that in S. prenanti. To investigate whether TGF-β1 in G. dobula possesses hypoxic adaptive features, Gd-TGF-β1 and Sp-TGF-β1 were cloned into an expression vector and transfected into 293-T cells, which are widely used due to their ease of culture, high transfectability, and well-characterized properties. We found that the survival rate of cells transfected with Gd-TGF-β1 was significantly higher than that of cells transfected with Sp-TGF-β1 after hypoxia treatment. Conclusions: These findings suggest that G. dobula may promote hypoxic adaptation through the activation and increased expression of TGF-β1. Changes in TGF-β1 expression may play a role in the adaptation of G. dobula to hypoxic conditions. Full article

Metal–organic frameworks (MOFs) are a class of highly ordered nanoporous crystals that possess a designable framework and unique chemical versatility. MOF thin films are ideal for nanotechnology-enabling applications, such as optoelectronics, catalytic coatings, and sensing. Mg-MOF-74 has been drawing increasing attention due to its remarkable CO₂ uptake capacity among MOFs and other commonly used CO₂ absorbents. Mg-MOF-74 thin films are currently fabricated by immersing selected substrates in precursor solutions, followed by a traditional solvothermal synthesis process. Herein, we introduce a rapid, easy, and cost-effective synthesis protocol to fabricate MOF thin films in an additive manner. In this work, the controllable synthesis of Mg-MOF-74 thin films directly on optical supports is reported for the first time. Dense, continuous, and uniform Mg-MOF-74 thin films are successfully fabricated on bare glass slides, with an average growth rate of up to 85.3 nm min⁻¹. The structural and optical properties of the resulting Mg-MOF-74 thin films are characterized using X-ray diffraction, atomic force microscopy, scanning electron microscopy, UV-Vis-NIR spectroscopy, and Fourier Transform Infrared Spectroscopy (FTIR). The CO₂ adsorption performance of the resulting Mg-MOF-74 thin films is studied using FTIR for the first time, which demonstrates that, as per the length of the light path for gas absorption, 1 nm Mg-MOF-74 thin film could provide 400.9 ± 18.0 nm absorption length for CO₂, which is achieved via the extraordinary CO₂ adsorption by Mg-MOF-74. The synthesis protocol enables the rapid synthesis of MOF thin films, highlighting Mg-MOF-74 in more CO₂-related applications, such as enhanced CO₂ adsorption and MOF-enhanced infrared gas sensing. Full article

The electromagnetic density of states (EM-DOS) plays a crucial role in understanding light–matter interactions, especially at metal–dielectric interfaces. This study explores the impact of interface geometry, material properties, and nanostructures on EM-DOS, with a focus on surface plasmon polaritons (SPPs) and evanescent waves. Using a combination of analytical and numerical methods, the behavior of EM-DOS is analyzed as a function of distance from metal–dielectric interfaces, showing exponential decay with penetration depth. The influence of different metals, including copper, gold, and silver, on EM-DOS is examined. Additionally, the effects of dielectric materials, such as Ti${\mathrm{O}}_2$, PMMA, and ${\mathrm{Al}}_2$${\mathrm{O}}_3$, on the enhancement of electromagnetic field confinement are discussed. The study also investigates the effect of nanostructures, like nanohole and nanopillar arrays, on EM-DOS by calculating effective permittivity and analyzing the interaction of quantum emitters with these structures. Results show that nanopillar arrays enhance EM-DOS more effectively than nanohole arrays, especially in the visible spectrum. The findings provide insights into optimizing plasmonic devices for applications in sensing, quantum technologies, and energy conversion. Full article

Diketopiperazines (DKPs) are biologically important cyclic dipeptides widespread in nature, associated primarily with microorganisms. This is the case for the 2,5-DKP derivative cyclo(L-Leu-L-Pro) (cLP), also known as gancidin W or PPDHMP, identified from a variety of bacteria and fungi, and occasionally found in food products. The present review retraces the discovery of cLP, its identification in living species, its chemical syntheses, and its biochemical properties. In bacteria, cLP is often associated with other DKPs to serve as a defense element against other microorganisms and/or as a regulator of bacterial growth. cLP plays a role in quorum-sensing and functions as an anticariogenic and antifungal agent. The antimicrobial mechanism of action and molecular targets of cLP are evoked. The interest in cLP for combatting certain parasitic diseases, such as malaria, and cancers is discussed. The capacity of cLP to interact with CD151 and to down-regulate the expression of this tetraspanin can be exploited to reduce tumor dissemination and metastases. The review sheds light on the pharmacology and specific properties of cyclo(L-Leu-L-Pro), which can be useful for the development of a novel therapeutic approach for different human pathologies. It is also of interest to help define the bioactivity and mechanisms of action of closely related DKP-based natural products. Full article

Most biomarkers exhibit abnormal expression in more than one disease, making conventional single-biomarker detection strategies prone to false-negative results. Detecting multiple biomarkers associated with a single disease can therefore substantially improve diagnostic accuracy. Accordingly, recent research has focused on precise multiplex detection, leading to the development of sensors employing various readout methods, including electrochemical, fluorescence, Raman, and colorimetric approaches. This review focuses on optical sensing applications, such as fluorescence, Raman spectroscopy, and colorimetry, which offer rapid and straightforward detection and are well suited for point-of-care testing (POCT). These optical sensors exploit nanoscale phenomena derived from the intrinsic properties of nanomaterials, including metal-enhanced fluorescence (MEF), Förster resonance energy transfer (FRET), and surface-enhanced Raman scattering (SERS), which can be tailored through modifications in material type and structure. We summarize the types and properties of commonly used nanomaterials, including plasmonic and carbon-based nanoparticles, and provide a comprehensive overview of recent advances in multiplex biomarker detection. Furthermore, we address the potential of these nanosensors for clinical translation and POCT applications, highlighting their relevance for next-generation disease diagnostic platforms. Full article

Nickel oxide (NiO), a wide bandgap p-type semiconductor, has emerged as a promising material for electrochemical sensing owing to its excellent redox properties, chemical stability, and facile synthesis. Its strong electrocatalytic activity enables effective detection of diverse analytes, including glucose, hydrogen peroxide, environmental pollutants, and biomolecules. Advances in nanotechnology have enabled the development of NiO-based nanostructures such as nanoparticles, nanowires, and nanoflakes, which offer enhanced surface area and improved electron transfer. Integration with conductive materials like graphene, carbon nanotubes, and metal–organic frameworks (MOFs) further enhance sensor performance through synergistic effects. Innovations in synthesis techniques, including hydrothermal, sol–gel, and green approaches, have expanded the applicability of NiO in next-generation sensing platforms. This review summarizes recent progress in the structural engineering, composite formation, and electrochemical mechanisms of NiO-based materials for advanced electrochemical sensing applications. Full article

Dental materials are well-established, with stainless steel 316L (SS) still being a common choice for components such as pediatric crowns and abutments. However, SS has some drawbacks, particularly in terms of mechanical properties and, more importantly, aesthetics, due to its metallic gray color. In this sense, PEEK (polyetheretherketone) has emerged as a promising material for dental applications, combining good mechanical properties with improved aesthetic features. This study compared the cytocompatibility of PEEK TiO₂ composite and SS using human fetal osteoblasts (hFOB) and human gingival fibroblasts (HGF). Cytocompatibility was evaluated over 1–7 days through metabolic activity and alkaline phosphatase (ALP) assays. Additionally, bacterial adhesion was assessed using Staphylococcus aureus and Pseudomonas aeruginosa in both monoculture and co-culture. The results showed that both materials were non-cytotoxic and supported cell growth. Notably, after 7 days of culture, PEEK TiO₂ surfaces promoted approximately 7% higher ALP activity than stainless steel, demonstrating a significantly enhanced osteogenic response (p < 0.01). Moreover, at day 7, PEEK TiO₂ promoted ~25% higher metabolic activity in HGF cells compared to SS. Regarding the bacterial adhesion, it was consistently low in PEEK TiO₂ for both S. aureus and P. aeruginosa, with a marked reduction (~50%) observed for P. aeruginosa under co-culture conditions. PEEK TiO₂ demonstrated enhanced biological performance and lower bacterial adhesion compared with SS, highlighting its potential as a biocompatible and aesthetically promising option for dental applications, including pediatric crowns. Full article

High-resolution three-dimensional (3D) Inverse Synthetic Aperture Radar (ISAR) imaging is essential for the characterization of target scattering in various environments. The practical application of this technique is frequently impeded by the lengthy measurement time necessary for comprehensive data acquisition with turntable-based systems. Sub-sampling the aperture can decrease acquisition time; however, traditional reconstruction algorithms that utilize matched filtering exhibit significantly impaired imaging performance, often characterized by a high peak side-lobe ratio. A methodology is proposed that integrates compressed sensing(CS) theory with sparse-aperture optimization to achieve high-fidelity 3D imaging from sparsely sampled data. An optimized sparse sampling aperture is introduced to systematically balance the engineering requirement for efficient, continuous turntable motion with the low mutual coherence desired for the CS matrix. A deep Bayesian optimization framework was developed to automatically identify physically realizable optimal sampling trajectories, ensuring that the sensing matrix retains the necessary properties for accurate signal recovery. This method effectively addresses the high-sidelobe problem associated with traditional sparse techniques, significantly decreasing measurement duration while maintaining image quality. Quantitative experimental results indicate the method’s efficacy: the optimized sparse aperture decreases the number of angular sampling points by roughly 84% compared to a full acquisition, while reconstructing images with a high correlation coefficient of 0.98 to the fully sampled reference. The methodology provides an effective solution for rapid, high-performance 3D ISAR imaging, achieving an optimal balance between data acquisition efficiency and reconstruction fidelity. Full article

The responsibility for risk assessment and user safety in forested and recreational areas lies with the property owner. This study shows that unmanned aerial vehicles (UAVs), combined with remote sensing and GIS analysis, effectively support the identification of high-risk trees, particularly those with reduced structural stability. UAV-based surveys successfully detect 78% of dead or declining trees identified during ground inspections, while significantly reducing labor and enabling large-area assessments within a short timeframe. The study covered an area of 6.69 ha with 51 reference trees assessed on the ground. Although the multispectral camera also recorded the red-edge band, it was not included in the present analysis. Compared to traditional ground-based surveys, the UAV-based approach reduced fieldwork time by approx. 20–30% and labor costs by approx. 15–20%. Orthomosaics generated from images captured by commercial multispectral drones (e.g., DJI Mavic 3 Multispectral) provide essential information on tree condition, especially mortality indicators. UAV data collection is fast and relatively low-cost but requires equipment capable of capturing high-resolution imagery in specific spectral bands, particularly near-infrared (NIR). The findings suggest that UAV-based monitoring can enhance the efficiency of large-scale inspections. However, ground-based verification remains necessary in high-traffic areas where safety is critical. Integrating UAV technologies with GIS supports the development of risk management strategies aligned with the principles of precision forestry, enabling sustainable, more proactive and efficient monitoring of tree-related hazards. Full article

The increasing demand for reliable, sensitive, and cost-effective gas sensors drives ongoing research in this field. Ideal gas sensors must demonstrate high sensitivity and selectivity, stability, rapid response and recovery times, energy efficiency, and affordability. One-dimensional (1D) metal oxide semiconductors (MOSs) are prominent candidates due to their excellent sensing properties and straightforward fabrication processes. The sensing efficacy of 1D MOSs is heavily dependent on their surface area and porosity, which influence gas interaction and detection efficiency. Polymeric templates serve as effective tools for enhancing these properties by enabling the creation of uniform, porous nanostructures with high surface area, thereby improving gas adsorption, sensitivity, and dynamic response characteristics. This review systematically examines the role of polymeric templates in the construction of 1D MOSs for gas sensing applications. It discusses critical factors influencing polymer template selection and how this choice affects key microstructural parameters, such as grain size, pore distribution, and defect density, essential to sensor performance. The recent literature highlights the mechanisms through which polymer templates facilitate the fine-tuning of nanostructures. Future research directions include exploring novel polymer architectures, developing scalable synthesis methods, and integrating these sensors with emerging technologies. Full article

Background: currently, there is a growing trend toward multifunctional cosmetics, which combine several active ingredients in a single product to enhance efficacy and user convenience. As ingredients may influence one another, it is important to study the behavior of mixing multiple compounds in complex formulations, especially regarding their interaction with the skin. Piceatannol, for instance, is a naturally occurring stilbene recognized for its in vitro potent antioxidant, anti-inflammatory, and anti-aging activities, making it a promising candidate for dermocosmetic use in suncare. But despite its beneficial biological activities, its cutaneous permeation remains poorly understood, particularly when delivered from complex formulations containing multiple ingredients. Objectives: in this sense, this study aimed to evaluate the in vitro skin diffusion profile of piceatannol from a passion fruit seed extract (P_ext) incorporated into a topical base (B_em) or an organic sunscreen emulsion (O_em), with or without a spilanthol-rich Acmella oleracea extract (J_ext) used as a natural permeation enhancer. Methods: due to ethical and variability issues with human and animal skins, the Strat-M™ synthetic membrane was chosen as a standardized model for the in vitro skin permeation assays. Piceatannol localization within membrane layers was examined by confocal Raman microscopy (CRM), while compound identification in donor and receptor compartments was performed via UHPLC-DAD. Results: piceatannol from B_em was detected up to 140 µm from the Strat-M™ surface and exceeded 180 µm in depth when J_ext and organic sunscreens were included in the formulation. Notably, formulations containing J_ext and those based on O_em promoted enhanced accumulation in both the stratum corneum and deeper skin layers, suggesting an improved delivery potential in lipid-rich vehicles. Conclusions: even though some instability issues were observed, piceatannol penetration into Strat-M™ from the proposed formulations was confirmed, and the results provide a foundation for further research on its topical delivery, supporting the rational development of formulations capable of harnessing its demonstrated biological properties. Full article

Background/Objectives: Psychoanalytic theories of destructiveness highlight its deep, unconscious origins tied to primal emotional and motivational mechanisms. Traditional psychiatric models of suicidal risk assessment focus on classic risk factors, limiting diagnostic and intervention approaches. This study examines the neuropsychoanalytic foundations of destructive tendencies, integrating sublimation and evolutionary motivational systems, redefining their role in the destruction process. Methods: A total of 480 AI-generated illustrations were assessed for interpretative accuracy. The final set was used in an online projection task with 204 respondents. Analyses included factorial exploration of the structure of the tool, assessment of psychometric properties (Cronbach α, ROC, AUC), logistic regression and analysis of intergroup differences. Results: Factor analysis identified eight subscales. Six of the eight factors showed thematic resemblance to Panksepp’s emotional systems, although this interpretation remains theory-driven and requires empirical validation. The remaining two—pursuit of destruction and its sublimation—extend beyond natural evolutionary mechanisms. Destructiveness was best explained by depression and psychological pain (OR = 1.39, 95% CI [1.26–1.52]), aggression and impulsivity (OR = 1.68, 95% CI [1.36–2.06]), and anxiety and a sense of threat (OR = 1.55, 95% CI [1.27–1.90]). Key predictors of destruction sublimation were curiosity (OR = 3.15, 95% CI [2.43–4.09]), closeness and love (OR = 3.43, 95% CI [2.48–4.76]), and pleasure and fun (OR = 3.08, 95% CI [2.26–4.20]). Analyses showed higher levels of destructiveness in individuals receiving psychological or psychiatric support, those with prior diagnoses, and students compared to employed individuals. Conclusions: Results indicate high reliability (Cronbach’s α > 0.87) and discrimination among internal subscale-defined groups (ROC > 0.7), supporting the tool’s potential in assessing destructive and sublimation tendencies within a neuropsychoanalytic framework. Future studies will explore its external validity and clinical applications. Full article

Forests play a crucial role in climate regulation through atmospheric CO₂ sequestration. However, disturbances like wildfires can severely compromise this function. This study assesses the ecological and economic consequences of a 2018 wildfire in The Roaches Nature Reserve, UK, focusing on post-fire carbon dynamics. A mixed woodland dominated by Pinus sylvestris L. and Larix decidua Mill. was evaluated via satellite imagery (remote sensing indices), dendrochronological analysis (wood cores sampling), and soil properties analyses. Remote sensing revealed areas of high fire severity and progressive vegetation decline. Tree-ring data indicated near-total mortality of L. decidua, while P. sylvestris showed greater post-fire resilience. Soil properties (e.g., soil organic carbon, biomass and microbial indices, etc.) assessed at a depth of 0–5 cm showed no significant changes. The analysis of CO₂ sequestration trends revealed a marked decline in burned areas, with post-fire sequestration reduced by approximately 70% in P. sylvestris and nearly 100% in L. decidua, in contrast to the stable patterns observed in the control stands during the same period. To estimate this important ecosystem service, we developed a novel CO₂ Sequestration Loss (CSL) index, which quantified the reduction in forest carbon uptake and underscored the impaired sequestration capacity of burned area. The decrease in CO₂ sequestration also resulted in a loss of regulating ecosystem service value, with burned areas showing a marked reduction compared to pre-fire conditions. Finally, a carbon loss of ~208 Mg ha⁻¹ was estimated in the burnt area compared to the control, mainly due to tree mortality rather than shallow soil carbon stock. Overall, our findings demonstrate that wildfire can substantially compromise the climate mitigation potential of temperate forests, highlighting the urgency of proactive management and restoration strategies. Full article