Search Results (547)

Currently, the escalating global problem of soil salinization severely limits the yield and quality of processing tomatoes. However, the differential responses and salt-tolerance strategies among processing tomato genotypes with different salt tolerances under salt stress remain largely elusive. Therefore, this study used salt-tolerant genotype ‘S39’ and salt-sensitive genotype ‘S37’ as materials. Seeds were sown in plug trays, and seedlings at the two-leaf-one-heart stage were transplanted into hydroponic containers filled with Hoagland nutrient solution. When seedlings reached the four-leaf-one-heart stage, they were exposed to NaCl treatments of 0 mM (control), 120 mM (Na120), and 180 mM (Na180). Plant samples were collected at 3, 6, and 9 days after treatment to determine growth parameters, physiological indices, and gene expression levels, aiming to reveal the dynamic differential responses to salt stress between the two processing tomato genotypes. The results demonstrated that the inhibitory effect of NaCl on the growth of processing tomatoes was aggravated with increasing NaCl concentration and treatment duration. The most significant difference in salt tolerance between the two genotypes was observed at 9 days under 180 mM NaCl treatment. At this sampling point, the relative salt-stress indices of superoxide dismutase (SOD) activity, peroxidase (POD) activity, soluble sugar content, proline content, chlorophyll a, chlorophyll b, and total chlorophyll (a + b) in ‘S39’ were significantly higher than those in ‘S37’ by 31.55%, 53.40%, 66.70%, 65.07%, 20.80%, 15.74%, and 19.44%, respectively. In addition, Na contents in roots and stems, as well as K contents in stems and leaves, were significantly higher in ‘S39’ than in ‘S37’ by 43.40%, 8.67%, 22.08%, and 21.99%, respectively. In contrast, relative electrolyte leakage and malondialdehyde (MDA) content in ‘S37’ were 15.54% and 12.44% higher than those in ‘S39’. In addition, photosynthetic parameters, including net photosynthetic rate (A_net), stomatal conductance (g_s), intercellular CO₂ concentration (C_i), transpiration rate (E), and chlorophyll fluorescence parameters, were more stable in ‘S39’ than in ‘S37’. In conclusion, ‘S39’ possesses stronger salt tolerance via a multi-level regulatory strategy involving an enhanced antioxidant enzyme system, elevated accumulation of osmoregulatory substances, improved mineral ion balance, and increased stability of the photosynthetic apparatus. This study provides a comprehensive multi-level analysis of the differential salt tolerance mechanisms in processing tomato genotypes with contrasting salt tolerances and lays a theoretical basis for the screening and identification of salt-tolerant germplasm in processing tomatoes. Full article

In the saline–alkaline lake (SAL) systems of the Nhecolândia region, Brazilian Pantanal, soils exhibit complex mineralogical assemblages controlled by sediment inheritance, pedogenesis, and hydrogeochemical gradients. This study investigates the distribution and transformation of 2:1 phyllosilicates along representative SAL toposequences. Soil samples were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), supported by granulometry and adjustment of the FTIR spectra. Mineralogical data were integrated with geochemical (Al, K, Mg, Ca, Na) and pH data and examined using principal component analysis (PCA). Greenish loamy horizons act as key morphological controls on hydrogeochemistry, regulating solute retention along mid- to downslope transitions. Illite is more strongly associated with upslope positions, whereas downslope alkaline environments are associated with smectitic phases (e.g., montmorillonite and Mg-rich varieties such as saponite) and mixed-layer minerals structures (e.g., illite–smectite and montmorillonite–vermiculite structures). These assemblages are consistent with non-linear transformation pathways, with illite as a possible transitional phase between micas and expandable structures. The PCA results suggest a primary mineral distribution structured by fine-material content and depth, while pH and alkalinity emerge as key geochemical controls that differentiate mineral stability fields and reinforce the hydrogeochemical compartmentalization of the profiles. Geochemical data show strong associations of Al, Mg, and K with fine-fraction accumulation. The integration of these approaches highlights that a 2:1 phyllosilicate assemblage results from multiple superimposed pedogenetic pathways, offering a conceptual framework for studying complex soil–lake systems. Full article

Water-based fracturing fluids, which are essential for enhancing oil and gas production, increasingly utilize seawater or produced water as alternatives to freshwater due to scarcity and cost considerations. However, the high salinity of these alternative water sources can compromise fluid stability and induce formation damage. Herein, the rheological behavior of borate-crosslinked hydroxypropyl guar (HPG) fracturing fluids was systematically evaluated in the presence of individual salts to elucidate the effects of ionic composition and concentration. Viscosity measurements at 80 °C and 170 s⁻¹ revealed that Ca²⁺ above 1500 mg/L reduced viscosity to below 50 mPa·s within 50 min, whereas Na⁺, K⁺, Mg²⁺ and SO₄²⁻ up to 10,000 mg/L exhibited no significant influence on viscosity and shear resistance. Among the cations investigated, Fe³⁺ exerted the most severe effect: only 15 mg/L Fe³⁺ caused viscosity to drop below 50 mPa·s within 30 min, far below the requirement for field applications. At elevated concentrations, MgCl₂, CaCl₂ and FeCl₃ compromised gel structural strength, while KCl-containing fluids demonstrated superior elastic resistance compared to NaCl at equivalent high concentrations. Microstructural analysis by SEM revealed that Na⁺, K⁺ and Mg²⁺ enhanced polymer hydration and HPG fiber entanglement, promoting the formation of well-defined network structures. In contrast, Ca²⁺ and Fe³⁺ disrupted the crosslinked gel architecture through complexation and electrostatic interactions with the polymer, resulting in reduced structural integrity. These findings provide critical insights for formulating fracturing fluids using saline or recycled water sources and inform targeted pretreatment strategies for flowback water in hydraulic fracturing operations. Full article

Solid-contact ion-selective electrodes (SC-ISEs) are typically constructed using ion-selective membrane (ISM)-based configurations. However, such structures often suffer from water-layer formation and the weak mechanical stability of the ISM. Herein, we report an ISM-free K⁺-SC-ISE based on a Prussian blue analogue transducer, KMnFe(CN)₆, eliminating the need for a conventional ionophore-based ISM layer. KMnFe(CN)₆ was synthesized via a one-step citrate-assisted co-precipitation method. The material functions as a bifunctional transducer, in which the open framework structure with ion-transport channels enables selective K⁺ recognition, while the redox-active Mn centers facilitate ion-to-electron transduction. The fabricated KMnFe(CN)₆-based K⁺ sensor exhibits a near-Nernstian response with a sensitivity of 52.3 ± 1.0 mV dec⁻¹ and a rapid response time of 25 s. The linear range and limit of detection were determined to 10⁻⁴ to 10⁻¹ M and 5.8 × 10⁻⁵ M, respectively. The sensor also demonstrates selectivity to representative interfering ions, with log K_ij of −2.39 ± 0.12 (Na⁺), −2.86 ± 0.09 (Li⁺), −3.06 ± 0.09 (Ca²⁺), −2.74 ± 0.12 (Mg²⁺) and −0.95 ± 0.08 (NH₄⁺). By eliminating the ISM layer, the water-layer effect is effectively avoided, resulting in excellent long-term stability with a potential drift of 57.2 ± 6.1 μV h⁻¹ over 7 days. The sensor was further applied to the analysis of K⁺ in real lake water samples, where the measured concentration showed good agreement with ion chromatography results. This work provides an ISM-free SC-ISE strategy for ion analysis in water environments. Full article

The electrolytic aluminum industry is facing severe challenges, such as excessive carbon consumption, resulting in more cost and environmental pollution due to the oxidation of carbon anodes. The isothermal oxidation resistance of B₄C-SiO₂-Albite (BSA) composite coating influenced by the in situ formation behavior and self-healing ability of the borosilicate glass at 1173 K was investigated through XRD, TG-DSC, Raman, FTIR spectroscopy, and SEM/EDS in this paper. The results show that the composite coating with 20 wt% B₄C has a relatively low mass gain rate of −0.082% after 24 h at 1173 K. It depends on the in situ formation of the amorphous borosilicate phase layer that can effectively protect the carbon anode from oxidation, which depends on the content of B₄C. The amorphous borosilicate glass forms from the reaction between the SiO₂ and the B₂O_3, from the oxidation of B₄C during exposure. More B₄C promotes the formation and volatilization of B₂O₃, which improves the viscosity and stability of the borosilicate glass by changing the glass network coupled with Na⁺ and Al³⁺ from Albite. It is a feasible strategy for designing durable coatings with appropriate B₄C addition for high-temperature applications. Full article

In biological systems, DNA serves as the primary carrier of genetic information, and the stability of its structure is fundamental to cellular function. Metal ions and temperature are critical environmental factors that modulate DNA conformation and activity. However, the differential morphological effects of alkali, alkaline earth, and transition metal ions, especially when combined with thermal treatment, have not been systematically visualized and quantified. In this work, atomic force microscopy (AFM) was employed to investigate the effects of different metal ions (Na⁺, K⁺, Mg²⁺, Ca²⁺, Cu²⁺) and temperature on DNA structure. The results demonstrated that monovalent ions (Na⁺ and K⁺) neutralized the negative charges on the DNA backbone, thereby reducing intermolecular electrostatic repulsion and promoting DNA aggregation into dendritic structures. Divalent ions (Mg²⁺ and Ca²⁺) not only provided more effective charge screening but also formed ion bridges between DNA strands, leading to more compact and cross-linked networks. In contrast, Cu²⁺ ions directly coordinated with DNA bases, causing local structural distortion and strand scission. Elevated temperatures induced DNA melting, with distinct morphological transitions from extended double strands to condensed single-stranded globules observed at temperatures exceeding the melting point ($T_m$). These findings elucidate the mechanisms by which environmental factors govern DNA morphology, providing insights relevant to nanotechnology and molecular biology applications. Full article

Background: Arginine and related amino acids are widely used to suppress protein aggregation, thereby affecting stability, manufacturability, and therapeutic performance. However, their effectiveness remains limited, necessitating the exploration of alternative strategies. Previous studies have shown that N-acetyl-L-arginine (NA-Arg) can improve protein stability; however, the potential of other N-acetylated amino acids has not been fully explored. Methods: This study aimed to investigate the effects of multiple N-acetylated amino acids as alternative excipients on aggregation, colloidal stability, and viscosity in intravenous immunoglobulin (IVIG) formulations. Dynamic light scattering (DLS) was used to evaluate diffusion behavior and aggregation tendencies, while complementary analyses were performed using size-exclusion chromatography (SEC) and flow-imaging microscopy (FI). Results: Overall, N-acetylation of amino acids improved colloidal stability, shifting the kD values from −5.87 to 6.83 mL/g for arginine and from −8.17 to 16.22 mL/g for histidine, and increased the aggregation onset temperature (Tagg) to above 60 °C. Among the tested compounds, N-acetyl-L-histidine (NA-His) showed the most favorable results, increasing the monomer proportion by approximately 4%, reducing high-molecular-weight species to below 2%, and producing a greater than 10-fold decrease in subvisible particles relative to histidine hydrochloride after 5 days of agitation. At 50 mM, both NA-His and NA-Arg reduced the viscosity of highly concentrated 200 mg/mL IVIG formulations, with NA-His exhibiting the lowest viscosity (7.24 ± 0.12 mPa·s). Protein–protein interaction and surface charge analyses indicated improved colloidal stability relative to parent amino acids, attributable to the presence of the acetyl group. Conclusions: These findings support the potential of N-acetylation as a strategy to modulate interaction-driven instability and suggest NA-His as a promising candidate excipient for stabilizing highly concentrated therapeutic proteins at acidic pH. Full article

Low-noise and high-stability constant-current drivers are critical components in precision electronic and optoelectronic systems, as current fluctuations directly limit the achievable system performance. This work presents a low-noise constant-current driver based on a current-sensing architecture combined with a parameters adjustable closed-loop control scheme, enabling effective suppression of current noise over a wide frequency range. The electrical performance of the proposed driver is first characterized at the circuit level. At an output current of 300 mA, a current noise spectral density of 15.22 $\mathrm{nA}/\sqrt{\mathrm{Hz}}@1 \mathrm{kHz}$ is achieved, corresponding to an integrated RMS current noise of 942.88 nA over the 1 Hz–1 MHz bandwidth and a relative current fluctuation of 4.6 ppm. To further evaluate system-level performance, the driver is tested using a laser-based load, where current-induced noise is converted into measurable phase and frequency fluctuations through optical beat-note operation.The experimental results demonstrate that this design effectively suppresses current-induced noise and improves system stability. Owing to its low noise performance, this design provides a practical solution for precision electronic and optoelectronic applications requiring low-noise current power supply. Full article

This study explored the physiological responses and gene expression profiles of the Manila clam (Ruditapes philippinarum) and the hard clam (Mercenaria mercenaria) under heat and hyposaline stress. Experimental conditions involved increasing the temperature from 25 °C to 35 °C and decreasing salinity from 25 ppt to 15 ppt over a 6 h acclimation period, followed by 72 h exposure. Key physiological and immune indicators, including filtration rate, oxygen consumption rate, ammonia excretion rate, and the expression of related genes, were measured. Under heat stress, R. philippinarum exhibited higher filtration, oxygen consumption, and ammonia excretion rates than M. mercenaria at most sampling time points. The expression of fatty acid desaturase (Δ6FAD) and heat shock protein (HSP70) genes increased and then decreased for both species, whereas superoxide dismutase (Cu/Zn SOD) gene expression gradually decreased over time. Furthermore, the expression levels of all three genes were generally significantly higher in M. mercenaria compared to R. philippinarum. Under hyposaline stress, R. philippinarum exhibited significantly higher filtration, oxygen consumption, and ammonia excretion rates than M. mercenaria between 24 h and 72 h. Expression levels of the Na⁺-K⁺-ATPase (NKAα), HSP70, and Cu/Zn SOD genes remained higher in M. mercenaria compared to R. philippinarum. Overall, the present study indicates that M. mercenaria maintains relative stability and R. philippinarum exhibits greater physiological fluctuation under both heat and hyposaline stress. This study highlights bivalve species-specific responses to environmental stressors and provides valuable insights for aquaculture planning and ecological management in different environmental regions, particularly in the context of global climate change. Full article

G-quadruplexes (G4s) are noncanonical nucleic acid structures involved in gene regulation and genome stability. Among them, the telomeric repeat-containing RNA (TERRA) forms biologically relevant RNA G4s (rG4s) that participate in telomere maintenance and genome stability. Although many ligands targeting DNA G4s have been reported, the recognition and modulation of RNA G4 topologies remain less explored. In this work, we investigated the interaction between TERRA and the spermine-functionalized Zn(II) porphyrin, ZnTCPPSpm4, using UV–vis absorption, fluorescence, resonance light scattering (RLS), and circular dichroism (CD) spectroscopy. In K⁺, where TERRA adopts a parallel G4 conformation, ZnTCPPSpm4 binds through a stepwise mechanism involving external end-stacking, forming discrete supramolecular complexes without altering the native topology. In contrast, under Na⁺ conditions, ZnTCPPSpm4 induces a gradual conformational rearrangement of TERRA from the antiparallel to a parallel-like G4 topology. A CD melting study showed that ZnTCPPSpm4 stabilizes the parallel RNA G4, while slightly destabilizing the antiparallel topology. Overall, our results demonstrate that ZnTCPPSpm4 is not a simple G4 binder, but a topology-selective ligand capable of remodeling TERRA G4 structures, highlighting the potential of metalloporphyrins as RNA G4-targeting scaffolds. Full article

Elaeagnus mollis oilseed (EMO) meal is a protein-rich by-product that may serve as a novel source of food-derived α-glucosidase inhibitory peptides. This study aimed to obtain EMO peptide fractions with enhanced α-glucosidase inhibition and to clarify the activity, stability and mechanism of the most active fraction. Fourteen proteases were compared, and 3.350 acidic protease was selected to establish an optimized hydrolysis process. The resulting EMO hydrolysate showed an IC₅₀ of 9.11 mg/mL against α-glucosidase and no detectable cytotoxicity towards HEK-293T cells at 0.1–12.0 mg/mL. Ultrafiltration yielded four fractions, among which the 3–10 kDa fraction exhibited the highest inhibition and maintained substantial activity under acidic pH (2–6), −20–50 °C, NaCl ≤ 5% and simulated gastrointestinal digestion. Kinetic analysis indicated mixed-type inhibition, while fluorescence, circular dichroism and molecular docking suggested that peptides in this fraction bind near the catalytic site of α-glucosidase and induce local conformational changes. These findings support EMO-derived 3–10 kDa peptides as stable, non-cytotoxic α-glucosidase inhibitors with potential as functional ingredients for dietary management of type 2 diabetes. Full article

Soil salinity severely constrains strawberry production by disrupting ion homeostasis and provoking oxidative injury. This study investigated whether soluble silicon (Si) and activated carbon (AC) act to enhance salt tolerance in strawberry (Fragaria × ananassa). Under NaCl stress, plants showed pronounced growth inhibition, increased Na⁺ accumulation and a deteriorated K⁺/Na⁺ balance, accompanied by elevated reactive oxygen species (ROS) and lipid peroxidation. In contrast, combined AC + Si treatment consistently provided the strongest protection, improving seedling vigor and survival. Relative to NaCl alone, AC + Si increased shoot and root fresh weight by 67.5% and 78.5%, reduced shoot Na⁺ by 59.1%, and lowered shoot H₂O₂ and MDA by 62.6% and 66.5%, respectively, indicating marked improvement in ion–redox homeostasis. Beyond plant responses, AC-containing treatments alleviated salt-induced increases in soil electrical conductivity, coinciding with a clear restructuring of the rhizosphere bacterial community and enrichment of putatively beneficial taxa. Transcriptome profiling further supported coordinated reprogramming of ion transport, redox control and stress-responsive signaling pathways under the AC + Si regime. Collectively, the results indicated that Si and AC co-application enhances strawberry salt tolerance through an integrated soil–plant–microbiome mechanism that stabilizes ion homeostasis and reinforces redox homeostasis. Full article

This study investigated the development of a perlite waste-based geopolymer for stabilizing iron ore tailings byproduct (IOTB) for geotechnical applications. Mixtures containing 70/30 and 80/20 proportions of byproduct and geopolymer were produced using perlite waste as the precursor and NaOH as the alkaline activator through the one-part method. Raw and geopolymer-stabilized IOTB, air-cured for 7, 14, and 28 days, were evaluated by ICP-OES, XRF, pH, geotechnical characterization, compaction, permeability, SEM, and consolidated drained triaxial tests under confining stresses ranging from 250 to 2000 kPa. The selected mixture presented a maximum dry density of 1.8 g/cm³ and optimum moisture content of approximately 14%. XRD results indicated sodium aluminosilicate phases associated with geopolymerization, with mechanical characteristics comparable to feldspar-type structures, while the pH increased from 6.5 to 12.5. Triaxial tests indicated that elastoplastic behavior persisted regardless of the geopolymer addition; however, SEM images confirmed matrix–particle bonding at grain contacts without significant pore filling. The cohesive intercept increased from 0 kPa in the IOTB to 89.1 kPa and 179.2 kPa after 14 and 28 days of curing, respectively, while the friction angle showed a slight increase of up to 7.7%. Deviatoric stress at failure and energy absorption capacity also increased with curing time. Hydraulically, the permeability coefficient remained within the same order of magnitude (10⁻⁴ cm/s), varying from raw IOTB of 2.73 × 10⁻⁴ cm/s to 3.28 × 10⁻⁴ cm/s after 28 days. These results demonstrated that geopolymer stabilization enhanced mechanical performance without compromising drainage capacity, representing a technically viable and socio-environmentally sustainable solution. Full article

Reducing sodium in poultry products often compromises texture and water-holding capacity. This study investigated the interactive effects of shiitake (Lentinula edodes) mushroom extract (SME) and ultrasound (US) on mitigating these defects in reduced-sodium chicken breast. A standard 2.0% NaCl brine served as the control, while reduced-sodium formulations contained 1.4% NaCl supplemented with 0.2% or 0.6% KCl. SME (0.4–1.2%) and probe US (20 kHz, 300 W, 15 min) were applied. Independently, SME increased brine uptake (15% at 1.2% SME), while US accelerated chloride diffusion (~30%) via microstructural disruption. The synergistic treatment combining 0.8% SME with US was identified as the statistical optimum. Simple effect analysis confirmed this combination significantly reduced cooking loss (p < 0.01) and restored comprehensive textural attributes to levels comparable with the 2.0% NaCl control. As confirmed by LF-NMR and microstructural analysis (H&E staining), these macroscopic improvements were highly correlated with optimized immobilized water (P₂₁) proportions and myofibrillar protein-matrix stabilization. Ultimately, this strategy provides a functional and microstructural basis for developing sodium-reduced poultry without compromising critical quality attributes. Full article

Highly polar M-mol-X (M = alkali metal, mol = molecule, X = halogen) insertion complexes have been predicted to offer potential practical applications, including molecular interactions with light, ion-pair induced isomerization, etc. In the present work, the insertion complexes of the seven-membered, fused bicyclic norcaradiene and its monocyclic isomer trapped in Li-I, Na-I, and K-I counterion pairs were investigated using ab initio methods. The structures, stability, polarities, and simulated infrared spectra are analyzed and the effects of the insertion on the norcaradiene to cycloheptatriene isomerization process are examined. Furthermore, an uncommon bond between iodine and a fully substituted carbon atom is reported upon and hypothesized to be catalyzed by the presence of the cation in the insertion complexes. Full article