Search Results (662)

Plasma-activated water (PAW) is enriched with reactive oxygen and nitrogen species (RONS). Application of PAW in plant cultivation demonstrated that RONS promote seed germination and early plant growth, as well as stimulate plant defense mechanisms. The aim of this paper was to investigate the potential of reactive nitrogen species in PAW to partially replace urea fertilizer nitrogen in lettuce cultivation without resulting in a negative effect on growth and mineral composition. Lettuce was grown under two treatments: urea only and a combined treatment in which 10% of the urea-derived nitrogen was replaced by an equivalent amount of nitrogen supplied via plasma-activated water (PAW). Plant growth parameters of lettuce (number of leaves, head weight, rosette diameter and height, and dry matter weight) were measured. Concentrations of 21 elements in the plants were analyzed using inductively coupled plasma optical emission spectroscopy (ICP—OES). Results showed no significant difference in growth parameters between the two treatments, as well as no significant difference between treatments in the concentrations of most elements except magnesium, boron and sodium. The results demonstrate that PAW reactive nitrogen can partially substitute for nitrogen from synthetic fertilizer without negative effects on the growth and nutritional content of lettuce. The study contributes to the development of sustainable horticultural fertilization practices and the adoption of environmentally friendly technologies. Full article

Cold stress is a major limiting factor for growth and quality in chrysanthemum. Enhancing cold tolerance helps plants better cope with low-temperature stress, increase antioxidant enzyme activity, and effectively inhibit excessive accumulation of reactive oxygen species (ROS). This study identifies the transcription factor DgWRKY6 as a key positive regulator in chrysanthemum’s cold response. DgWRKY6 is localized in the nucleus and shows high expression levels in leaf tissue, which is strongly induced by cold stress. Cold treatment also activates its promoter region. Physiological assays demonstrate that overexpression of DgWRKY6 enhances ROS scavenging, reduces membrane damage, and improves cold tolerance by increasing the activities of glutathione S-transferase (GST) and peroxidase (POD), whereas DgWRKY6 knockout lines exhibit the opposite phenotype. Real-time quantitative PCR (RT-qPCR), yeast one-hybrid (Y1H), dual-luciferase reporter assays (Dual-LUC), and chromatin immunoprecipitation-qPCR (ChIP-qPCR) confirmed that DgWRKY6 directly binds to the W-box element and activates DgGST transcription. In conclusion, DgWRKY6 plays a positive regulatory role in enhancing cold tolerance in chrysanthemum by activating DgGST transcription in response to cold stress, ultimately increasing GST activity, reducing ROS accumulation, and enhancing antioxidant responses under low temperatures. This finding provides a valuable molecular target for cold tolerance breeding in chrysanthemum and other related horticultural crops. Full article

This study examined the geopolymerization behavior of granite waste powder and reactive silica powder (GWS), utilizing granite waste powder as a sustainable precursor material, to develop an environmentally friendly substitute for Ordinary Portland cement. To obtain this objective, a total of three different mixes of calcined granite waste with reactive silica (1:1, 3:2, 7:3) were cast to evaluate the aim of this study. Due to low inherent reactivity of granite waste powder, the alkali activation was achieved using a combined solution of alkali activators consisting of 8 mol/L concentration of NaOH and Na₂SiO₃ solution at mass ratio of 1:1.2 prepared 24 h in advance to ensure complete dissolution and stabilization prior to pouring it into the GWS paste. The finest particle size distribution for optimal reactivity performance was achieved by choosing lowest median particles size from 4.0 μm–4.2 μm among all mixtures. ICP-MS analysis of granite waste and reactive silica showed the presence of silica (0.11% and 0.26% respectively) and calcium (49.61% and 38.92% respectively) content adequate for effective geopolymerization of the paste. The elemental composition, new phase formation and microstructural analysis were examined using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) techniques and Scanning Electron Microscopy (SEM) analysis. XRD analysis revealed that all GWS mixes were predominantly amorphous, with crystalline quartz, feldspar and minor α-cristobalite peaks diminishing from GWS50 to GWS70 confirming increased reactivity due to enormous reactive silica content. FTIR spectra of GWS mixes displayed characteristics of O-H (3375 cm⁻¹), H-O-H (1645 cm⁻¹), and Si-O-T (982–1000 cm⁻¹) bands, with the main Si-O-T peak shifting to higher wavenumbers from GWS50 to GWS70 due to increased GW content, indicating reduced geopolymerization effect in GWS50. SEM analysis revealed that among all mixes, GWS70 exhibited the most ideal dense matrix with increasing content of granite waste along with strong N-A-S-H gel formation. Compressive strength at 28 days increased from 11.2 MPa for GWS50 to 14.2 MPa for GWS60 and 13.8 MPa for GWS70, demonstrating that higher reactive silica powder content significantly enhanced the mechanical performance of the alkali-activated paste. These findings demonstrated that alkali-activated geopolymers of GSW offer a viable alternative to Ordinary Portland cement with optimized mixes by valorizing industrial waste and reducing reliance on high-carbon cement production. Full article

Amidst rapid urbanization, fine particulate matter (PM_2.5) has emerged as a critical environmental challenge in China, posing substantial health risks due to its complex composition and diverse sources. This study provides a seasonally resolved analysis of PM_2.5 composition and multi-faceted toxicity in Hefei, a major Chinese manufacturing center. PM_2.5 samples collected across four seasons were chemically characterized for water-soluble ions, carbonaceous components, metals, and polycyclic aromatic hydrocarbons (PAHs) and derivatives. Their toxicological effects were evaluated through oxidative potential (OP), cytotoxicity, and reactive oxygen species (ROS) generation in the human bronchial epithelial cell line BEAS-2B. The results reveal significant seasonal variations in PM_2.5 concentration and composition. Winter exhibited the highest PM_2.5 levels (68.31 ± 17.12 μg/m³), with enrichment of secondary inorganic aerosols (SIAs), toxic metals (Pb, Cd, As), and high-molecular-weight PAHs. Spring showed elevated crustal elements (Al, Fe, Mn), while summer had the lowest pollutant concentrations. Toxicity assays reflected the following patterns: winter PM_2.5 demonstrated the highest OP (0.1423 ± 0.0368 nmol DTT/min/μg), strongest cytotoxicity (51.85% cell viability), and greatest ROS induction (2.28-fold increase). Statistical analyses identified distinct toxicity drivers: OP was associated with SIA (NO₃⁻, NH₄⁺) and redox-active metals (Cu, Zn); cytotoxicity correlated with toxic metals and PAHs; whereas ROS showed weaker compositional correlations. This integrated “composition–toxicity” assessment reveals that the elevated health risk in winter stems from a synergistic mix of secondary aerosols and combustion-derived toxicants, urging a shift toward component-specific, risk-based air quality management strategies. Full article

A new category of polyphenolic compounds, like flavonoids, phenolic acids, phenylpropanoids, terpenoids, and others, referred to as food nutrients, may counteract the harmful effects of micro- and nanoplastics (MNPs) by enhancing cellular stress resilience response and overall human health. These compounds found in functional food help mitigate the cellular damage, inflammation, and oxidative stress caused by MNP exposure, which can contribute to pathological conditions, including diabetes. Importantly, specific food nutrients are able to activate, at the minimum dose, the nuclear factor erythroid-derived 2-like 2 (Nrf2) to prevent or block MNP-induced damage. The Nfe2l2 gene encodes the Nrf2 transcription factor, acting as a master regulator of redox homeostasis by inducing antioxidant response element (ARE)-driven resilience genes, which in turn, promote the expression of detoxification enzymes like heme oxygenase-1 (HO-1), NAD(P)H: quinone oxidoreductase 1 (NQO1), and glutathione S-transferase (GST) to scavenge reactive oxygen species (ROS) and shield cells from environmental damage and toxicity. Deregulation of the Nfe2l2 gene due to the accumulation of MNP pollutants may exacerbate the inflammatory conditions associated with diabetes and its chronic complications by rendering cells more sensitive to oxidative stress, apoptosis, and pyroptosis. Furthermore, epigenetic modifications influence gene regulation; chromatin remodeling directly impacts DNA accessibility, allowing or limiting transcription factor access to regulate gene expression. This mechanism may also play a pivotal role in the progression of oxidative stress-related diseases, as it modulates the Nrf2 pathway and the expression levels of its target genes. In contrast to the current literature, which has only addressed the pathological mechanisms induced by MNPs, this research explores, for the first time, how food nutrients interacting with the Nfe2l2 gene can combat or reverse the toxic effects of MNPs in cells, tissues, and organs. The goal is to improve health by attenuating MNP toxicity, which is influenced by individual genetic variations and cellular stress resilience. Full article

The Zhundong coalfield in Xinjiang contains vast reserves and is a crucial source of thermal coal. However, the Zhundong coal has a high content of alkali and alkaline earth metals, which makes it prone to ash deposition and slagging in boilers, thereby limiting its large-scale utilization. Fluidized-bed preheating is an emerging clean combustion technology that can reduce the slagging and fouling risks associated with high-alkali coal by modifying its fuel properties. This study employs circulating fluidized-bed preheating technology to treat high-alkali coal, with a focus on investigating the effect of the preheated air equivalence ratio on fuel preheating modification. Through microscopic characterization of both the raw coal and preheated char, the release and transformation behaviors of elements and substances during the preheating process are revealed. The results demonstrate that fluidized preheating promotes alkali metal precipitation, and increasing the preheated air equivalence ratio (λ_Pr) enhances gas production and elemental release, with a volatile fraction mass conversion of up to 84.57%. As the λ_Pr value increased from 0.28 to 0.40, the average temperature in the preheater riser increased from 904 °C to 968 °C. Compared to the raw coal, the specific surface area of the preheated char was enhanced by a factor of 3.6 to 9.1 times, with a more developed pore structure and less graphitization, thus enhancing the surface reactivity of the preheated char. The increase in λ_Pr also facilitated the conversion from pyrrolic nitrogen to pyridinic nitrogen, thus improving combustion performance and facilitating subsequent nitrogen removal. These findings provide essential data support for advancing the understanding of preheating characteristics in high-alkali coal and for promoting the development of efficient and clean combustion technologies tailored for high-alkali coal. Full article

The relevance of this study is determined by the need for new technological solutions to enhance the productivity of wells producing heavy and highly viscous crude oil. The work investigates multicomponent Al–Ga–In–Sn alloys as reactive systems capable of generating heat and hydrogen upon contact with water. The focus is placed on optimizing melting parameters and assessing how alloy composition and structural features affect reactivity. Phase composition was analyzed by X-ray diffraction, microstructure by SEM-EDX, and elemental composition by XRF. The results show that the hydrogen generation rate and heat release depend on melting temperature, holding time, and ratios of activating metals, as well as the physicochemical properties of the formation water, particularly salinity and pH. Reaction enthalpy and conversion efficiency were quantified. The highest hydrogen output and thermal effect were observed for the following compositions—90 wt.% Al, 5 wt.% Ga, 2.5 wt.% In, 2.5 wt.% Sn; and 85 wt.% Al, 5 wt.% Ga, 5 wt.% In, 5 wt.% Sn (825 °C, 30 min). Rapid heat and gas release is attributed to the eutectic structure and micro-galvanic interaction, which eliminate the induction period. These findings demonstrate the potential of such alloys for in situ heating, enhanced oil recovery, and autonomous hydrogen-energy applications. Full article

The growing prevalence of multidrug-resistant (MDR) Candida spp. necessitates the development of new antifungal strategies. Photodynamic therapy (PDT), already widely used in the treatment of various oral infections, is based on the synergistic interaction of three key elements: a photosensitizer capable of selectively binding to microbial cells, a light source with the appropriate wavelength, and the presence of molecular oxygen. This interaction results in the production of singlet oxygen and reactive oxygen species, responsible for the selective destruction of microorganisms. In recent years, numerous natural compounds have been explored as potential photosensitizers. Olive oil, a cornerstone of the Mediterranean diet, was recently recognized by the U.S. Food and Drug Administration as a medicinal substance thanks to its soothing, immunomodulatory, and antimicrobial properties, which have also been documented in regard to oral administration. Materials and Methods: The aim of this in vitro study was to evaluate the efficacy of activated olive oil as a novel photosensitizer in PDT against Candida species. Oral MDR clinical isolates of C. albicans, C. krusei, and C. glabrata were analyzed using the Kirby–Bauer method according to EUCAST protocols. Six different experimental conditions were considered for each strain: (i) 100 μL of extra-virgin olive oil (EVOO); (ii) 100 μL of EVOO pre-activated with 3% H₂O₂ (EVOO-H); (iii) 100 μL of EVOO irradiated for 5 min with polarized light (480–3400 nm, 25 W); (iv) 100 μL of EVOO-H subjected to the same polarized light; (v) 100 μL of EVOO irradiated for 5 min with a 660 nm diode laser (100 mW); and (vi) 100 μL of EVOO-H irradiated with the same laser. All plates were incubated at 37 °C for 48 h. Results: The results showed a variable response among the different Candida species. C. glabrata showed sensitivity to all experimental conditions, with a 50% increase in the diameter of the inhibition zone in the presence of polarized light. C. krusei showed no sensitivity under any of the conditions tested. C. albicans showed antifungal activity exclusively when EVOO-H was activated by light. In particular, activation of EVOO and EVOO-H with polarized light resulted in the largest inhibition zones. Conclusions: In conclusion, olive oil, both alone and pre-activated with hydrogen peroxide, can be considered an effective photosensitizer against drug-resistant Candida spp., especially when combined with polarized light. Full article

Cannabinoids can bind to several cannabinoid receptors and modulate cellular signaling and gene expression relevant to inflammation and lipid homeostasis. Likewise, several vitamin E analogs can modulate inflammatory signaling and foam cell formation in macrophages by antioxidant and non-antioxidant mechanisms. We analyzed the regulatory effects on the expression of genes involved in cellular lipid homeostasis (e.g., CD36/FAT cluster of differentiation/fatty acid transporter and scavenger receptor SR-B1) and inflammation (e.g., inflammatory cytokines, TNFα, IL1β) by cannabinoids (cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC)) in human THP-1 macrophages with/without co-treatment with natural alpha-tocopherol (RRR-αT), natural RRR-αTA (αTAn), and synthetic racemic all-rac-αTA (αTAr). In general, αTAr inhibited both lipid accumulation and the inflammatory response (TNFα, IL6, IL1β) more efficiently compared to αTAn. Our results suggest that induction of CD36/FAT mRNA expression after treatment with THC can be prevented, albeit incompletely, by αTA (either αTAn or αTAr) or CBD. A similar response pattern was observed with genes involved in lipid efflux (ABCA1, less with SR-B1), suggesting an imbalance between uptake, metabolism, and efflux of lipids/αTA, increasing macrophage foam cell formation. THC increased reactive oxygen species (ROS), and co-treatment with αTAn or αTAr only partially prevented this. To study the mechanisms by which inflammatory and lipid-related genes are modulated, HEK293 cells overexpressing cannabinoid receptors (CB1 or TRPV-1) were transfected with luciferase reporter plasmids containing the human CD36 promoter or response elements for transcription factors involved in its regulation (e.g., LXR and NFκB). In cells overexpressing CB1, we observed activation of NFκB by THC that was inhibited by αTAr. Full article

This study investigated the effect of mechanical activation on the physicochemical properties of lepidolite and the leaching behavior of mechanically activated samples in sulfuric acid (H₂SO₄). Lepidolite was mechanically activated using a high-energy planetary ball mill (PBM) at 400 RPM with a 20:1 ball-to-feed weight ratio (BFR, g:g) and the samples activated for different durations were characterized for amorphous phase content, particle size, and morphology using various solid analyses. X-ray diffraction (XRD) revealed the progressive amorphization of lepidolite, with the amorphous fraction increased from 34.1% (unactivated) to 81.4% after 60 min of mechanical activation. Scanning electron microscopy (SEM) showed that mechanically activated particles became fluffy and rounded, whereas unactivated particles retained lamellar and angular shapes. The reactivity of minerals after mechanical activation was evaluated through a 2 M H₂SO₄ leaching test at different leaching temperatures (25–80 °C) and time periods (30–180 min). Although the leaching efficiencies of Li and Al slightly improved at higher leaching temperatures and longer leaching times, the leaching of these metals was primarily governed by the mechanical activation time. The highest Li and Al leaching efficiencies—87.0% for Li and 79.4% for Al—were obtained from lepidolite that was mechanically activated for 60 min under leaching conditions of 80 °C and a 10% (w/v) solid/liquid (S/L) ratio for 30 min. The elemental mapping images of leaching feed and residue produced via energy dispersive spectroscopy (EDS) indicated that unactivated particles in the leaching residue had much higher metal content than mechanically activated particles. Kinetic analysis further suggested that leaching predominantly occurs at mechanically activated sites and the apparent activation energies calculated in this study (<3.1 kJ·mol⁻¹) indicate diffusion-controlled behavior with weak temperature dependence. This result confirmed that mechanical activation significantly improves reactivity and that the residual unleached fraction can be attributed to unactivated particles. Full article

Quercetin (Q), a bioactive flavonoid, exerts potent antioxidant and redox-modulating effects by activating the nuclear factor erythroid 2-related factor 2/antioxidant response Element (Nrf2/ARE) pathway and upregulating endogenous antioxidant defenses, including enzymatic antioxidants such as superoxide dismutase (SOD) and catalase (CAT), as well as non-enzymatic glutathione (GSH) and lipid peroxidation (MDA). Gemcitabine (Gem), a widely used antimetabolite chemotherapeutic, often shows limited efficacy under hypoxic and oxidative stress conditions driven by hypoxia-inducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF)-mediated angiogenesis. This study investigated the redox-mediated synergistic effects of Q and Gem in MDA-MB-231 human breast cancer cells. Combination treatment significantly reduced cell viability beyond the expected Bliss value, indicating a synergistic interaction and enhanced apoptosis compared with single-agent treatments. Increased reactive oxygen species (ROS) production was accompanied by depletion of GSH and accumulation of MDA, establishing a pro-apoptotic oxidative stress environment. Q alone enhanced SOD and CAT activities, whereas the combination induced exhaustion of antioxidant defenses under oxidative load, reflecting a redox-adaptive response. Molecular analyses revealed downregulation of HIF-1α and VEGF, alongside upregulation of Bax and Caspase-3, confirming suppression of hypoxia-driven survival and activation of the intrinsic apoptotic pathway. Transcriptomic and enrichment analyses further identified modulation of oxidative stress- and apoptosis-related pathways, including phosphoinositide-3-kinase–protein kinase B/Akt (PI3K/Akt), HIF-1 and VEGF signaling. Collectively, these results indicate that Q potentiates Gem cytotoxicity via redox modulation, promoting controlled ROS elevation and apoptosis while suppressing hypoxia-induced survival mechanisms, highlighting the therapeutic potential of redox-based combination strategies against chemoresistant breast cancer. Full article

Drought events intensified by climate change severely compromise the physiological stability and productivity of Coffea arabica, particularly in rainfed systems, underscoring the need to identify cultivars with greater functional resilience. This study evaluated the physiological, nutritional and biochemical responses of seedlings from ten cultivars subjected to adequate irrigation (AW), severe water deficit (SWD) and rehydration (RI). Water potential, gas exchange, oxidative stress markers, stomatal traits and foliar macro- and micronutrients were quantified. Most cultivars exhibited pronounced reductions in the pre-dawn leaf water potential (Ψ_pd), photosynthesis (A), stomatal conductance (g_s) and transpiration (E), together with increases in oxidative stress indicators under SWD. In contrast, Obatá amarillo, Castillo, and Arará maintained greater hydraulic stability, more efficient stomatal regulation, higher water-use efficiency, and lower oxidative stress, accompanied by a more effective post-stress recovery after RI. Regarding nutrient dynamics, Geisha, Castillo, and Arará showed higher K⁺ accumulation, while Catimor bolo presented elevated Ca²⁺, P, and Fe²⁺ contents, elements associated with metabolic reactivation and structural recovery after stress. Geisha and Marsellesa displayed an adaptive, recovery-driven resilience strategy following drought stress. Overall, the findings identify Obatá amarillo, Castillo, and Arará as the most drought-tolerant cultivars, highlighting their potential relevance for breeding programs aimed at improving drought resilience in coffee. Full article

Low-frequency alternating-current (LFAC) transmission has attracted significant attention for medium- and long-distance offshore wind integration due to its ability to mitigate the substantial charging currents and reactive power burdens associated with long submarine cables. This paper investigates the frequency-dependent electrothermal behaviors of a 500 kV three-core XLPE submarine cable using a coupled electromagnetic–thermal finite-element model. The simulation framework evaluates the current distribution, power losses in metallic components, temperature rise, and ampacity across various frequency regimes. To validate the numerical model, a thermal-circuit approach based on the IEC 60287 standard is developed, with comparisons confirming that deviations remain within acceptable engineering margins. The study reveals that operating at lower frequencies effectively mitigates skin and proximity effects, leading to reduced conductor and sheath losses. Quantitative results demonstrate that reducing the operating frequency from 50 Hz to 5 Hz results in a 30.6% reduction in total power losses and a 14.2% increase in current-carrying capability. These findings confirm that LFAC transmission offers a viable pathway to enhance the efficiency and capacity of submarine power transmission systems. Full article

12-oxo-phytodienoic acid reductase (OPR) is a core component of the jasmonic acid (JA) biosynthetic pathway and participates in JA synthesis by catalyzing the reduction in the precursor 12-oxo-phytodienoic acid (OPDA), as well as broadly regulating plant development, stress response, and hormone signaling networks. This study analyzed the OPR gene family using 28 soybean genomes. A total of 15 OPR gene family members in soybean were identified, including 14 core genes and one variable gene. Analysis of gene duplication types showed that whole-genome duplication (WGD)/segmental duplication was the main mode of duplication in GmOPRs. The phylogenetic tree constructed from multiple species showed that the OPRs in subgroup VII were functionally important OPR genes and that the OPRs underwent Leguminosae and Cruciferae divergence, and large-scale duplication occurred in Leguminosae. Analysis of natural selection pressures on 28 soybean accessions indicated that the overall evolutionary pressures on GmOPRs were dominated by purifying selection, but there were also potential positive selection signals. Analysis of cis-acting elements revealed a large number of light- and hormone-responsive cis-acting elements in the GmOPRs. Some specific cis-acting elements were only present in a few genes or accessions. The protein interaction network consisted of 12 GmOPR proteins, 4 allene oxide synthase (AOS) proteins, and 6 allene oxide cyclase (AOC) proteins, where AOCs interact with GmOPRs and AOSs. Tissue transcriptome expression profiling showed that GmOPR3, GmOPR7, and GmOPR15 were specifically expressed in roots, whereas GmOPR2, GmOPR10, and GmOPR14 were specifically expressed in leaves, suggesting that these genes play an important role in the growth and development of the tissues. Moreover, GmOPRs usually responded to salt stress, and GmOPR3, GmOPR8, GmOPR9, GmOPR10, and GmOPR11 were significantly up-regulated in roots and leaves under salt stress. This suggests that these genes may be involved in biological processes such as osmoregulation, ion homeostasis, and scavenging of reactive oxygen species, thus helping soybeans to resist salt stress. This study comprehensively analyzed the OPR gene family in soybean based on the 28 soybean accessions and clarified the salt stress response pattern, which provides a new and more effective and reliable way to analyze the soybean gene family. Full article

Copper and nickel ions play pivotal, albeit distinct, roles as essential trace elements in living systems, and primarily serve as co-factors for a range of enzymes. However, as with all trace metal ions, excessive concentrations can exert adverse toxicological properties. Interestingly, the incorporation of these in cell culture media can establish novel chemical interactions, with their speciation status markedly influencing characteristics, including cell maturation, and cellular uptake mechanisms. Thus, the primary objective of this study was to investigate and determine the speciation status (i.e., complexation) of nickel(II) and copper(II) ions by biomolecules present in RPMI 1640 mammalian cell culture medium using virtually non-invasive high-resolution proton NMR analysis, an investigation of much relevance to now routine studies of their toxicological actions towards cultured cells. Samples of the above aqueous culture medium were ¹H NMR-titrated with increasing added concentrations of 71–670 µmol/L Ni(II)(aq.), and 0.71–6.7, 7.1–67 and 71–670 µmol/L Cu(II)(aq.), in duplicate or triplicate. ¹H NMR spectra were acquired on a JEOL ECZ-600 spectrometer at 298 K. Results demonstrated that addition of increasing concentrations of Ni(II) and Cu(II) ions to the culture medium led to the selective broadening of a series of biomolecule resonances, results demonstrating their complexation by these agents. The most important complexants for Ni(II) were histidine > glutamine > acetate ≈ methionine ≈ lysine ≈ threonine ≈ branched-chain amino acids (BCAAs) > asparagine ≈ aspartate > tyrosine ≈ tryptophan, whereas for Cu(II) they were found to be histidine > glutamine > phenylalanine ≈ tyrosine ≈ nearly all remaining aliphatic metabolites (particularly the wealth of amino acids detectable) > 4-hydroxyphenylacetate (trace culture medium contaminant), in these orders. However, Cu(II) had the ability to influence the linewidths of these signals at much lower added levels (≤7 µmol/L) than that of Ni(II), the broadening effects of the latter occurring at concentrations which were approximately 10-fold greater. Virtually all of these added metal ion-induced resonance modifications were, as expected, reversible on addition of equivalent or excess levels of the chelator EDTA. From this study, changes in the co-ordination sphere of metal ions in physiological environments can give rise to marked modifications in their physicochemical properties (e.g., redox potentials, electronic charges, the potential catalytic generation of reactive oxygen species (ROS), and cell membrane passages). Moreover, given that the above metabolites may also function as potent hydroxyl radical (^●OH) scavengers, these findings suggest that generation of this aggressively reactive oxidant directly from Cu(II) and Ni(II) ions in physiologically-relevant complexes may be scavenged in a ‘site-dependent’ manner. This study is of further relevance to trace metal ion research in general since it enhances our understanding of the nature of their interactions with culture medium biomolecules, and therefore provides valuable information regarding their overall chemical and biological activities, and toxicities. Full article