Search Results (118)

Intensive irrigated agriculture relies heavily on nitrogen fertilization, which may cause ammonium accumulation, highly detrimental to sensitive seedlings. Silicon application has emerged as a potential strategy to mitigate this stress, although the underlying mechanisms remain poorly understood. To evaluate this effect, maize seedlings were grown in nutrient solution under five N concentrations (1.4, 3.6, 7.1, 14.3, and 28.6 mmol L⁻¹), applied in the presence or absence of silicon (1.8 mmol L⁻¹ Si). The nitrogen source was a mixture of nitrate and ammonium in a N-NO₃⁻: N-NH₄⁺ ratio of 4:5. Silicon was supplied as monosilicic acid (H₂SiO₃). Plant growth, leaf area, root morphology (length, diameter, density), N and Si accumulation, uptake and utilization efficiency, SPAD index, nitrate reductase activity, and proline content were evaluated. Silicon supplementation enhanced nitrate reductase activity, SPAD values, leaf area, and root traits, reduced proline in roots and shoots, and improved N uptake and partitioning. Among the tested N concentrations, 14.3 mmol L⁻¹ achieved the highest efficiency of nutrient absorption and biomass production, highlighting silicon as a sustainable strategy to mitigate ammonium stress in maize seedlings. Full article

Triple-negative breast cancer (TNBC) is known for being aggressive and potentially resistant to chemotherapy. This means that new ways to improve cancer treatments are a priority. So, the anticancer effect of binary combinations of fucoidan (FuLt) and the chemotherapeutic agents doxorubicin, paclitaxel, and 5-fluorouracil was evaluated. The Chou-Talalay combination index method was used to do this. This method allows the assessment of interactions between products by determining synergism, additive effect and antagonism with combination index <1, =1 and >1, respectively. Synergistic indices (SIs) were selected and applied to 4T1 homotypic spheroids. Oxidative stress caused by SIs was determined after 72 h by measuring the production of ROS and NO in both homotypic and heterotypic spheroids. Three SIs with an inhibitory effect of at least ≥ 0.50 and a dose reduction index > 1 were selected. Considering the experimental and simulated SI, twelve, nineteen, and seven SIs were found for FuLt with doxorubicin, paclitaxel, and 5-fluorouracil, respectively. The highest levels of ROS and NO occurred at 12 and 72 h, respectively, in homotypic and heterotypic spheroids, indicating an immunomodulatory effect in heterotypic spheroids. These results suggest that the synergistic combination of FuLt with chemotherapeutic agents improves drug efficacy and modulates redox dynamics in 4T1 spheroids. Furthermore, FuLt alone exhibits cytotoxic properties. Full article

Silicon (Si) is a beneficial element that alleviates the adverse effects of salinity in plants. Despite extensive evidence of Si-mediated stress alleviation in other crops, information for tropical fruit species such as Passiflora edulis remains limited, especially regarding the efficiency of different application methods. This study evaluated two yellow passion fruit cultivars (BRS Sol do Cerrado and BRS Gigante Amarelo) at the seedling stage under five management conditions: irrigation with 1.2 dS m⁻¹ water (control), 4.0 dS m⁻¹ water (salt stress), and salt stress combined with Si applied via soil, foliar spray, or both (soil + foliar), using silicic acid as the Si source. The experiment was conducted in a completely randomized design in a 2 × 5 factorial arrangement with five replicates. High salinity decreased foliar nutrient concentrations, gas exchange, and seedling quality, whereas Si mitigated these effects depending on the application method and cultivar. Combined soil and foliar application increased nutrient contents, biomass, and the Dickson Quality Index, especially in BRS Gigante Amarelo. These findings provide new insights into Si management for P. edulis and offer practical implications for improving nutrient balance, growth, and seedling performance under saline conditions. Full article

Salt stress is a major form of abiotic stress that disrupts soybean germination and early seedling establishment. In this study, physiological, biochemical, and transcriptomic analyses—including germination index, antioxidant enzyme activity, and RNA-seq profiling—were conducted during soybean germination to elucidate early responses to salt stress and biostimulant treatment. A preliminary screening of six biostimulants (nanoparticle zinc oxide (NP-ZnO), nanoparticle silicon dioxide (NP-SiO₂), silicon dioxide (SiO₂), glucose, humic acid, and fulvic acid) revealed NP-SiO₂ as the most effective in promoting germination under salt stress. Under 150 mM NaCl, NP-SiO₂ increased the germination rate and length of the radicle compared with the control, also enhancing peroxidase and ascorbate peroxidase activities while reducing malondialdehyde accumulation, suggesting alleviation of oxidative stress. RNA sequencing revealed extensive transcriptional reprogramming under salt stress, identifying 4579 differentially expressed genes (DEGs) compared with non-stress conditions, while NP-SiO₂ treatment reduced this number to 2734, indicating that NP-SiO₂ mitigated the transcriptional disturbance caused by salt stress and stabilized gene expression networks. Cluster analysis showed that growth- and hormone-related genes suppressed by salt stress were restored under NP-SiO₂ treatment, whereas stress-responsive genes that were induced by salt were attenuated. Hormone-related DEG analysis revealed that NP-SiO₂ down-regulated the overactivation in the abscisic acid, jasmonic acid, and salicylic acid pathways while partially restoring gibberellin, auxin, cytokinin, and brassinosteroid signaling. Overall, NP-SiO₂ at 100 mg/L mitigated salt-induced oxidative stress and promoted early soybean growth by fine-tuning physiological and transcriptional responses, representing a promising nano-based biostimulant for enhancing salt tolerance in plants. Full article

Understanding the impact of hydric stress on medicinal plants in the context of climate change is becoming increasingly important. This study aimed to assess the quality of a seed lot of Agastache mexicana subsp. mexicana (Amm) through a novel calculation of the Vigour Index on time basis (${VI}_T$). The evaluation was based on relationships among plant height, leaf number, survival time, and plant density across six irrigation regimes, referred to as stages, which differed in the timing and quantity of water, designed to impose water stress from seedling emergence until plant death. To maximise growth and survival time, we utilised two input factors: Artificial Shade Levels (ASLs) of 38%, 87%, and 94%, as well as Silicon Dioxide Levels (SDLs) of 0.0%, 0.2%, 0.4%, and 0.8%. The effects of these treatments were measured using the Survival Index (SI) and the ${VI}_T$. The plants achieved their highest SI and ${VI}_T$ values influenced by minimum mortality and maximum height and leaf number in stage three. This behaviour aligned with the field capacity of the substrate, supporting the evaluation of stages one and two as waterlogging stress, while the remaining stages were classified as drought stress. The ${VI}_T$ results showed statistically significant effects from ASL, particularly at 94%. However, the ${VI}_T$ in relation to SDL was not statistically significant. The ${VI}_T$ measurements were visualised using spline interpolation, a method that provides an effective approach to quantify adverse conditions affecting Amm’s development and that it can support to identify the hydric stresses type. Full article

This treatise studies the thermal sensitivity of the mechanical and optical transmission coefficients of a microoptoelectromechanical (MOEM) accelerometer based on evanescent coupling in a temperature range from minus 40 to plus 125 °C. Two types of optical measuring transducers are considered: based on a directional coupler and a resonator. This analysis covers the optical and mechanical components of the thermal sensitivity of the transmission coefficient. In terms of the mechanical part, the temperature effect induces changes to the linear dimensions of the structure and material characteristics and causes internal mechanical stresses as well. The temperature effect on the optical system of the accelerometer is conditioned by the thermo-optic effect of the materials the optical waveguides are made of. This study includes experiments on the refraction index dependence on the temperature of the optical films that compose the optical system of the MOEM accelerometer. The experiment shows that the refraction index of the films grows with temperature and amounts to 0.12642 ppm/°C for silicon nitride on the SiO₂/Si substrate. For the optical measuring transducer based on a directional coupler, the thermal sensitivity of the accelerometer’s optical transmission coefficient is 580 ppm/°C. For the resonator-based transducer, the thermal sensitivity is 0.33 °C⁻¹. The thermal sensitivity of the normalized mechanical transmission coefficient of the accelerometer is 120 ppm/°C. For optical measuring transducers based on a directional coupler, the contribution of the temperature dependent refraction index alteration to the overall error is 5 times larger than that of the MOEM accelerometer’s mechanical parameters, while for the resonator-based transducer the difference reaches 3000 times. This means its operability is only possible in a thermostatic environment. Full article

Background: Sedentary behavior (SB) is a growing public health concern associated with cardiometabolic risk; yet few studies have assessed integrated physiological responses across the muscle–fat–vascular system. Methods: This retrospective cross-sectional analysis used data from 13,637 participants (≥12 years) in the 2011–2018 National Health and Nutrition Examination Survey (NHANES). Sedentary duration (SD) was self-reported via a validated questionnaire. Outcomes included the sarcopenic index (SI), fat distribution index (FDI), and pulse pressure index (PPI). Associations were examined using multivariable linear regression and restricted cubic spline models, adjusting for sociodemographic and lifestyle factors. Subgroup analyses explored effect modification by body mass index (BMI), sex, race/ethnicity, education, and self-rated health. Results: Each additional hour/day of SD was associated with a lower SI (β = −0.004, 95% CI: −0.005 to −0.002), lower FDI (β = −0.009, 95% CI: −0.012 to −0.007), and higher PPI (β = 0.001, 95% CI: 0.000 to 0.002). The SD–SI association was nonlinear, with a threshold at 10.73 h/day: below this point, the SI declined sharply (β = −0.001, p < 0.001), while above it the slope plateaued or reversed. The FDI showed consistent adverse associations across the SD range, particularly in men and individuals with lower education. The PPI was significantly elevated with SD only among non-Hispanic Black participants. Conclusions: SD is differentially associated with muscle mass, fat distribution, and vascular function, with overlapping inflection points indicating a coordinated multisystem response to sedentary stress. These findings support targeting <10.7 h/day sedentary time as a potential intervention threshold. Full article

Polyphenolic compounds, commonly found in Greek medicinal plants, exhibit promising antiviral and antioxidant properties, making them potential candidates for therapeutic purposes. This study aims to evaluate the antiviral activity of nine selected polyphenols against Dengue virus (DENV) and Yellow Fever virus (YFV) life cycles, alongside their antioxidant capacity determined by the DPPH method and the ABTS assay, and their ability to inhibit DNA strand scission induced by peroxyl radicals. Kaempferol and caffeic acid demonstrated the most potent inhibitory effects on DENV genome replication, while coumaric acid blocked viral entry more effectively. Notably, among the nine compounds, kaempferol exhibited the strongest anti-DENV effect, especially at the level of virus-released infectivity, showing the lowest EC₅₀ (3.55 μΜ) and the highest selectivity index (SI = 25.45). In contrast, none of the compounds showed significant antiviral activity against YFV genome replication. Concomitantly, caffeic acid and kaempferol had the highest radical scavenging activity (DPPH and ABTS assays), highlighting their dual properties. Moreover, DNA scission inhibition assays confirmed the strong antioxidant potential of all tested compounds, with caffeic acid and kaempferol achieving the highest inhibition rate of 98.98% and 97.34% respectively. These findings underscore the potential of specific polyphenols, particularly kaempferol and caffeic acid, as antiviral and antioxidant agents targeting DENV and oxidative stress-related damage. Full article

Optical phase modulation is essential for a wide range of silicon photonic integrated circuits used in communication applications. In this study, an optical phase shifter utilizing photo-elastic effects is proposed, where mechanical stress is induced by electrostatic micro-electro-mechanical systems (MEMS) with actuators arranged in a comb drive configuration. The design incorporates suspended serpentine silicon nitride (SiN) optical waveguides. Through extensive numerical simulations, it is shown that the change in the effective refractive index (n_eff) of the optical waveguide is a function of the voltage applied to the electrostatic actuators and that such n_eff tuning can be achieved for a broad range of wavelengths. Implemented within one arm of an unbalanced Mach–Zehnder interferometer (MZI), the phase shifter achieves a phase change of π when the stressed optical path measures 4.7 mm, and the actuators are supplied with 80 V DC and consume almost no power. This results in a half-wave voltage-length product (V_πL) of 37.6 V·cm. Comparative analysis with contemporary optical phase shifters highlights the proposed design’s superior power efficiency, compact footprint, and simplified fabrication process, making it a highly efficient component for reconfigurable MEMS-based silicon nitride photonic integrated circuits. Full article

Recycled asphalt pavement (RAP) can support traffic loads comparable to those of roads constructed with conventional materials. The structural evaluation of RAP is performed through the deflection generated by vehicles via recoverable deflection in the pavement layers. The deflection record is translated into a curve that geometrically interprets the behavior of the layers that make up the pavement. In this study, a falling weight deflectometer (FWD) was used to emulate transit loads and measure deflection in two models. Both contained 30% RAP, and one of them had fiberglass geogrid in the center of the asphalt layer. Through normalized maximum deflection (limit value based on constant stress), the structural index (SI), and the dynamic stiffness modulus (DSM), the structural behavior of the models under different load levels was evaluated. The pavement structure exhibited similarities in strength for both models subjected to impact. The presence of the geogrid reinforcement (Z1) showed structural index values ranging between 0.17 and 0.54, while the layer without geogrid (Z2) presented structural index values in a range of 0.23 to 0.78. In addition, the dynamic stiffness modulus presented a difference of 10 kN/mm between the maximums of the models in favor of reinforcement with glass fiber geogrid. Therefore, low structural index values are associated with the interaction between RAP and geogrid, highlighting this combination as an innovative and functional system for road surfaces, while the dynamic stiffness modulus indicates the stability and structural integrity of sustainable pavement, which has the potential to extend its lifespan. Full article

Fire retardancy and thermal management are critical for energy-efficient, fire-safe buildings. Natural wood, a mainstream construction material, possesses inherent advantages but lacks such dual functionality. Silicified wood was fabricated via multi-cycle silicification of native wood, where SiO₂ uniformly infiltrates and fills the lumens. The treated wood material displays an improved limiting oxygen index (LOI) from 21.9% to 36.0%, and delayed ignition from 15 s to 50 s, compared to untreated wood. It demonstrates a low thermal conductivity of 0.074 W·m⁻¹·K⁻¹, showing enhanced emissivity. When heated on a 75 °C hot plate, the silicified wood surface reaches ~50 °C after 5 s, versus ~60 °C for native wood. These enhancements collectively improve thermal management performance, achieving insulation through reduced thermal conduction and passive cooling via optimized infrared regulation. Ultimate tensile stress remains nearly unchanged post-treatment, while toughness is significantly improved. This work advances wood as a sustainable building material, with promising potential for fire-safe, energy-efficient construction applications. Full article

Accurate estimation of winter wheat yield under saline stress is crucial for addressing food security challenges and optimizing agricultural management in regional soils. This study proposed a method integrating Sentinel-2 data and field-measured soil salt content (SC) using a random forest (RF) method to improve yield estimation of winter wheat in Kenli County, a typical saline area in China’s Yellow River Delta. First, feature importance analysis of a temporal vegetation index (VI) and salinity index (SI) across all growth periods were achieved to select main parameters. Second, yield models of winter wheat were developed in VI-, SI-, VI + SI-, and VI + SI + SC-based groups. Furthermore, error assessment and spatial yield mapping were analyzed in detail. The results demonstrated that feature importance varied by growth periods. SI dominated in pre-jointing periods, while VI was better in the post-jointing phase. The VI + SI + SC-based model achieved better accuracy (R² = 0.78, RMSE = 720.16 kg/ha) than VI-based (R² = 0.71), SI-based (R² = 0.69), and VI + SI-based (R² = 0.77) models. Error analysis results suggested that the residuals were reduced as the input parameters increased, and the VI + SI + SC-based model showed a good consistency with the field-measured yields. The spatial distribution of winter wheat yield using the VI + SI + SC-based model showed significant differences, and average yields in no, slight, moderate, and severe salinity areas were 7945, 7258, 5217, and 4707 kg/ha, respectively. This study can provide a reference for winter wheat yield estimation and crop production improvement in saline regions. Full article

Alzheimer’s disease (AD) is a complex neurodegenerative disorder characterized by multifactorial pathogenesis, including oxidative stress, cholinergic dysfunction, β-amyloid (Aβ) aggregation, and neuroinflammation. In this study, we investigated the neuroprotective potential of the Pheka capsule (PC) formula, a traditional Thai polyherbal medicine comprising Oroxylum indicum (OI), Zingiber officinale (ZO), and Boesenbergia rotunda (BR). Phytochemical analysis by HPLC confirmed the presence of key bioactive compounds including baicalein, baicalin, oroxylin A, 6-gingerol, 6-shogaol, pinocembrin, and pinostrobin. The PC formula exhibited strong antioxidant activity, highly selective butyrylcholinesterase (BChE) inhibition with a selectivity index (SI) of BChE > 20, suppression of Aβ aggregation, and protection against H₂O₂-induced neuronal damage in vitro. Network pharmacology analysis identified multiple AD-relevant targets and pathways, including APP, GSK3B, CASP3, GAPDH, PTGS2, and PPARG, implicating the PC formula in modulating oxidative stress, apoptosis, and inflammation. Notably, OI emerged as the primary contributor to the formula’s multitargeted actions. These findings support the therapeutic potential of the PC formula as a multitarget agent for AD, aligning with the growing interest in polypharmacological strategies for complex neurodegenerative diseases. Further in vivo and clinical studies are warranted to confirm its efficacy and safety. Full article

Increased global drought severity threatens crop yield and quality. Fulvic acid (FA), a humic acid compound, enhances crop stress tolerance. This study investigated FA application on drought-stressed tomato ‘Provence’ during the seedling and fruiting stages. Seedling-stage drought severely inhibited growth, physiology, biochemistry, and photosynthesis, reducing seedling quality. Subsequent fruiting-stage drought further significantly decreased photosynthetic efficiency and assimilate synthesis, drastically lowering fruit yield and quality. FA application mitigated drought damage, with 400 mg·L⁻¹ being optimal. At this concentration, under seedling drought, Seedling strength index (Si), Photosynthetic efficiency (Pn), and Instantaneous water use efficiency (IWUE) increased significantly by 76.54%, 67.46%, and 36.97%, respectively, with no adverse morphological effects by flowering. Post-drought FA spraying later significantly enhanced leaf photosynthetic enzyme activity and WUE (by 89.16%, 98.48%, 42.20%, and 40%), boosting Pn, promoting assimilate accumulation and transport to fruits. This resulted in significantly improved fruit yield and comprehensive quality. In conclusion, spraying 400 mg·L⁻¹ FA significantly enhances tomato drought tolerance and water use efficiency in arid/semi-arid regions, offering an effective strategy for saving irrigation water and improving crop productivity in water-scarce areas. Full article

The influence of structural water in alumina (Al₂O₃) and silica (SiO₂) coated titanium dioxide (TiO₂) pigments on the photodegradation behavior of polypropylene (PP) composites was investigated. Four commercial rutile TiO₂ pigments with varying surface inorganic coatings were incorporated into PP plaques and subjected to accelerated UV weathering to simulate outdoor exposure. Photodegradation was assessed through gloss retention measurements, the carbonyl index (CI), and stress at break retention, while pigment morphology and composition were analyzed using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Surface charge and water content were determined through the zeta potential (ζ), Karl Fischer titration, thermogravimetric analysis (TGA), and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results showed that low-alumina coating alone led to the lowest photodegradation resistance, the highest CI, and the lowest stress at break retention. In contrast, increasing alumina content enhanced photostability, reaching its maximum for combined alumina–silica coatings, which mitigated electron–hole pair migration. PP composites with high alumina–silica-coated TiO₂ exhibited higher gloss retention (36%) compared to low-alumina samples (21%). Furthermore, statistical analysis using ANOVA revealed significant differences in coating content and ζ potential among the pigment grades. These findings provide novel insights into oxide-water interactions and the impact of structural water on the photodegradation of polymer composites. Full article