Search Results (195)

Chronic kidney disease (CKD) affects approximately 700 million people worldwide and is a major contributor to end-stage renal disease (ESRD), cardiovascular morbidity, and premature mortality. Although oxidative stress has long been considered central to CKD progression, conventional antioxidant strategies have not consistently improved clinical outcomes, suggesting that excess reactive oxygen species (ROS) alone cannot fully account for the underlying disease pathophysiology. Emerging evidence supports a broader paradigm of redox network failure, characterized by the disruption of coordinated signaling among ROS, nitric oxide (NO), and reactive sulfur species (RSS). Within this framework, hydrogen sulfide (H₂S), a major endogenous RSS, functions as a key regulator of renal redox homeostasis. CKD is consistently associated with systemic and renal H₂S deficiency, accompanied by downregulation of cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST), as well as impaired transsulfuration and disrupted mitochondrial sulfide oxidation. Importantly, this deficiency cannot be explained solely by reduced renal function but instead reflects active suppression of H₂S biosynthesis. Uremic toxins, particularly indoxyl sulfate (IS), contribute to this process through activation of the aryl hydrocarbon receptor (AhR), which inhibits specificity protein 1 (Sp1)-dependent transcription of H₂S-producing enzymes. This IS–AhR–Sp1 axis provides a mechanistic link between toxin accumulation and disruption of the sulfur arm of the redox network, amplifying oxidative stress, endothelial dysfunction, mitochondrial impairment, ferroptotic vulnerability, and fibrotic remodeling. Beyond H₂S itself, downstream RSS, including persulfides, polysulfides, and thiosulfate, may represent the principal bioactive mediators of sulfur-dependent redox signaling, and their coordinated depletion in CKD may impair redox buffering capacity beyond what H₂S measurement alone reflects. This review integrates current evidence to propose a conceptual model in which CKD progression involves failure of coordinated redox signaling—characterized by feed-forward network collapse and threshold-dependent transition to a self-sustaining high-ROS state—with H₂S deficiency representing one mechanistically supported component of this broader network disruption. This framework highlights the therapeutic potential of targeting redox network restoration rather than isolated oxidative pathways in CKD. Full article

Soil quality is a critical determinant of crop productivity. This study assessed the soil quality of 61 barley farmlands in central and northern Hubei Province based on ten soil chemical properties: pH, soil organic matter (SOM), ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N), hydrolyzable nitrogen (HN), available phosphorus (AP), available potassium (AK), exchangeable calcium (Exc-Ca), exchangeable magnesium (Exc-Mg), and available sulfur (AS). A total of 68.85% of the farmlands were acidic (pH < 6.5). The average levels of SOM, NH₄⁺-N, NO₃⁻-N, and HN were deficient, while AP was moderate, according to the Second State Soil Survey of China (SSSSC). AK, Exc-Ca, Exc-Mg, and AS were, on average, at moderate-to-abundant levels. Differences in preceding crops led to significant differences in pH and SOM between paddy and dryland fields. A minimum data set was established using six soil properties (HN, AS, AK, Exc-Ca, Exc-Mg, and NH₄⁺-N) to calculate the soil quality index (SQI). SQI ranged from 0.27 to 0.69, with an average of 0.45, indicating overall low soil quality in the region. Both accuracy importance and R²-weighted importance revealed that HN was the most influential factor driving SQI variation among the soil properties examined. This study elucidates the status of soil nutrients, offering a diagnostic basis for developing targeted fertilization strategies for barley in this region. Full article

Hydrogen peroxide (H₂O₂) is widely regarded as a clean and high-value chemical; however, its conventional industrial production remains both energy-intensive and environmentally unsustainable. In this study, sulfur-deficient ZnIn₂S₄ (denoted SDZIS) was developed as an efficient photocatalyst for H₂O₂ generation through oxygen reduction under visible-light irradiation. SDZIS photocatalysts with controllable sulfur-vacancy concentrations were synthesized via a one-step citric-acid-assisted hydrothermal process combined with NaOH etching. The results of transient photocurrent response and electrochemical impedance spectroscopy show that the separation efficiency of charge carriers has been improved. Compared with pristine ZnIn₂S₄, the optimized SDZIS catalyst achieved a nine-fold enhancement in the H₂O₂ production rate, reaching 2711.81 μmol g⁻¹ h⁻¹. Results of experimental and density functional theory calculations suggest that sulfur vacancies can modulate the catalyst work function and the adsorption energy of O₂. Comparative experiments indicate that an appropriate concentration of sulfur vacancies can lead to a high H₂O₂ yield. Combined with scavenger tests, DMPO-EPR, and rotating ring disk electrode measurements, these results support a sulfur-vacancy-associated enhancement in charge separation and a tendency toward a superoxide-involved 2e⁻ ORR pathway for H₂O₂ production. Full article

The detection of sulfur hexafluoride (SF₆) decomposition products is critical for diagnosing insulation faults in gas-insulated switchgear (GIS). In this study, a vanadium-doping strategy was incorporated into the graphene/MoS₂ (GM) heterojunction to design a vanadium-doped graphene/MoS₂ (GMV) heterojunction material. Leveraging first-principles density functional theory (DFT), the adsorption behaviors of five characteristic SF₆ and its decomposition gases (H₂S, SO₂, SOF₂, SO₂F₂) on intrinsic GM and GMV were systematically investigated to evaluate their potential for gas sensing applications. Computational results reveal that intrinsic GM exhibits only weak physical adsorption toward all target molecules, with low adsorption energies and negligible charge transfer, which fails to meet practical application requirements. In contrast, GMV demonstrates significantly enhanced adsorption energies for H₂S, SO₂, and SOF₂ at vanadium sites (with a maximum value of −0.388 eV for SO₂) and shorter adsorption distances, while SO₂F₂ and SF₆ preferentially adsorb near electron-deficient carbon regions. Intrinsic GMV displays semimetallic properties, with a Fermi level at 0.126 eV and a band gap of 0.0017 eV. Upon adsorption of H₂S, SOF₂, SO₂F₂, or SF₆, the Fermi level undergoes a moderate shift (ranging from −1.083 eV to +0.349 eV), with minimal changes in the band gap. Conversely, SO₂ adsorption induces a substantial downward shift of the Fermi level to −1.732 eV, accompanied by the emergence of a sharp partial density of states (PDOS) peak near the Fermi level (0–1.5 eV), indicating strong orbital coupling and significant charge transfer. Furthermore, recovery times calculated using classical formulas show that at room temperature and a frequency of 1 × 10⁶ Hz, the recovery time of GMV for SO₂ is 2.43 s, outperforming the other four gases and satisfying practical gas sensing requirements. Through comprehensive analysis of adsorption distances, electronic structure changes, and recovery times, GMV exhibits higher selectivity toward SO₂. Thus, GMV can serve as a sensing material for detecting GIS insulation faults associated with elevated SO₂ concentrations, offering a viable strategy for advancing online monitoring technologies in power systems. Full article

The aim of this study was to investigate how delayed fertilization with individual macronutrients (N, P, K, Ca, Mg, and S) affects the growth, yield components, biomass, and spectrophotometric indicators of spring wheat grown under controlled hydroponic conditions. Nutrient deprivation was initiated at BBCH stage 23 and maintained for 21, 28, 35, or 133 days, corresponding to BBCH stages 30, 32, 37, and 99, respectively. In selected treatments, the complete nutrient solution was subsequently restored until harvest to evaluate recovery potential. N, P, and Ca deprivation exerted the strongest negative effects on biomass accumulation across all deprivation durations. Compared to the fully supplied control, biomass was reduced by 60% under N deprivation and by 44.5% under P deprivation after 21 days. After 35 days, calcium deprivation resulted in a 97.7% reduction in biomass. Following 133 days of deprivation, biomass was reduced by 98%, 96.8%, and 95.9% under N, calcium, and P deficiencies, respectively. Root mass followed a similar pattern: after 21 days, it decreased by 52.46% (N) and 36.44% (P); after 28 days—by 57.4% (N) and 52.7% (P); after 35 days—by 90.7% (Ca), 66% (N), and 59.1% (P); and after 133 days—by 95.1–90.1% (Ca, N, P). Magnesium deprivation caused substantial reductions in growth parameters, reflecting its central role in chlorophyll structure and photosynthetic efficiency. Sulfur deprivation resulted in moderate but consistent biomass suppression and spectral divergence, indicating its importance in protein synthesis and redox regulation. Short-term deficiencies allowed partial recovery of growth and productivity, whereas long-term deprivation induced pronounced morphological alterations linked to stress adaptation. These effects were further confirmed through in vivo spectral reflectance measurements compared to healthy control plants. Full article

Frataxin is a conserved mitochondrial protein essential for cellular iron–sulfur (Fe–S) cluster biogenesis and oxidative balance, with its deficiency causing Friedreich’s ataxia in humans. The hypomagnetic field (HMF), an environmental stressor known to influence oxidative stress and neurodevelopment, may interact with such inherent metabolic vulnerabilities. This study investigated whether HMF exposure exacerbates Fe–S homeostasis and oxidative disruption in a Drosophila melanogaster model of frataxin deficiency. Using synchrotron radiation-based X-ray fluorescence (SR-XRF) spectroscopy for in situ elemental analysis in live tissues, we found that HMF significantly altered iron distribution and content in a tissue-specific manner. In frataxin-silenced brains, HMF decreased iron distribution but increased total iron content, whereas in eyes it reduced iron content. Sulfur content decreased in frataxin-deficient eyes but increased in brains under HMF, though its spatial distribution was unchanged. Critically, HMF elevated reactive oxygen species (ROS) in frataxin-deficient brains. Transcriptomic analysis identified 202 differentially expressed genes under HMF in frataxin-silenced flies, including key regulators of iron metabolism and oxidative stress pathways. These findings demonstrate that HMF disrupts tissue-specific iron and sulfur homeostasis and intensifies oxidative stress in a frataxin-deficient insect system, underscoring its role as an environmental factor capable of aggravating metabolic fragility. Full article

Postmenopausal osteoporosis is an age-related condition in which estrogen deficiency drives low-grade inflammation and oxidative stress, disrupting the homeostatic balance between bone formation and resorption. Since osteopenia represents a critical intermediate stage, preventive strategies are essential to mitigate its progression. Preclinical studies suggest that hydrogen sulfide (H₂S), a gaseous mediator with antioxidant properties, protects bone metabolism by supporting osteoblast function and suppressing osteoclast activity. Building on this evidence, we conducted the first exploratory clinical trial assessing the effects of inhalation therapy with sulfurous mineral waters on systemic biomarkers in postmenopausal women with osteopenia. Thirty-eight eligible participants underwent a daily inhalation of sulfurous waters (14.6 mg/L sulfide) for 12 consecutive days. Biomarkers of oxidative stress, inflammation, and bone turnover were assessed at baseline, immediately post-treatment, and five days after cessation in the serum of patients. The treatment was well tolerated and did not cause any early adverse effect. Serum H₂S levels, measured in a subset of participants, significantly increased, confirming systemic bioavailability. Sulfurous water inhalation induced a marked change in oxidative stress, with malondialdehyde levels declining by up to 37% from baseline. Pro-inflammatory cytokines, particularly IL-8 and MIP-1α, were significantly decreased (up to 50–70%) at the end of the treatment. Reference bone turnover markers P1NP and CTX-1 did not show significant changes; however, BALP exhibited a significant increase, suggesting the activation of pathways linked to biomineralization. These findings provide preliminary human evidence that inhaled sulfurous waters enhance systemic H₂S bioavailability and modulate redox and inflammatory pathways associated with bone remodeling in osteopenic women, supporting the rationale for further controlled pharmacodynamic investigations evaluating the potential of H₂S in bone health. Full article

Over the past five decades, cereal production has increased largely through fertilizer-driven yield gains to meet rising global food demand. Sulphur (S) is an essential macronutrient required for plant growth and development, although its role in crop production has often been underemphasized compared with other major nutrients. Unintentional sulfur accumulation from atmospheric deposition has traditionally been sufficient for most crops, but recent trends indicate a steady decline in soil sulfur levels worldwide. This decline is largely attributable to reductions in atmospheric sulfur deposition, the widespread use of sulfur-free high-NPK fertilizers, and increased sulfur uptake by high-yielding crop varieties. Despite increasing yield losses associated with sulfur deficiency, sulfur fertilization remains inadequately adopted in many crop production systems. In cereals, sulfur deficiency not only reduces growth and yield but also alters the synthesis of sulfur-containing amino acids and storage proteins, thereby weakening grain processing, baking, and nutritional quality. Additionally, sulfur deficiency in cereal grains has emerged as a notable health concern. Nevertheless, sulfur fertilization alone may not effectively mitigate these challenges, as optimal sulfur uptake, distribution, and assimilation depend on precise synchronization with plant developmental stages through complex physiological processes. Further research on the genetic regulation of these physiological mechanisms is critical to enhancing sulfur use efficiency and sustaining cereal crop production systems in the coming years. Full article

The Jiaodong gold-mineralized area is one of the most significant gold districts in China. The newly discovered Moshan gold deposit is hosted in the Late Jurassic Queshan granite, previously considered a prospecting blind zone. In this study, pyrite from the Moshan gold deposit is examined as the primary research subject. To elucidate the ore-forming processes and genetic mechanisms of this deposit, we conducted a comprehensive mineralogical and geochemical study on pyrite, the principal gold-bearing mineral. EPMA and LA-MC-ICP-MS analyses reveal that the pyrite is slightly sulfur-deficient (average S/Fe ratio of 1.976) and exhibits trace element variations (As, Co, and Ni) strongly correlated with distinct metallogenic stages. Gold occurs in various forms, including visible inclusion gold, fracture gold, and invisible nano-particulate gold (Au⁰). The in situ sulfur isotope δ³⁴S values range from 7.11‰ to 9.40‰ (average 8.00‰), displaying high homogeneity and a positive deviation from the troilite in the Canyon Diablo iron meteorite. By integrating pyrite S-Fe relationships, Co-Ni-As systematics, and sulfur isotope characteristics, the study indicates that the Moshan gold deposit originates from a magmatic-hydrothermal source. The ore-forming materials predominantly derive from Mesozoic granite-derived magmatic-hydrothermal fluids, with a minor contribution from crustal basement materials. The depth of mineralization is interpreted as mid-shallow. These findings not only highlight the metallogenic potential of the Queshan granite and clarify the genetic relationship between the Moshan gold deposit and other regional gold deposits but also provide a novel theoretical foundation and technical support for deep gold exploration in the Jiaodong region. Full article

Autotrophic denitrification using sulfur compounds is considered an alternative to heterotrophic denitrification for the treatment of organic carbon-deficient wastewaters. However, the stoichiometric characteristics of denitrification using different sulfur species, particularly thiocyanate (SCN⁻) and sulfite (SO₃²⁻), remain poorly understood. Here, partial autotrophic denitrification driven by thiocyanate or sulfite was studied in two batch reactors. The stoichiometry of thiocyanate-oxidizing denitrification was assessed based on valence and ultimate product analysis. No nitrate removal was observed in the sulfite-fed system, indicating that sulfite could not serve as an effective electron donor for autotrophic denitrification under the tested conditions. In contrast, simultaneous removal of SCN⁻ and NO₃⁻ was achieved in the thiocyanate-fed system, with removal efficiencies of 100% and 92.5 ± 3.6%, respectively. After 36 h, total nitrogen removal reached 63.3%, with nitrite identified as the dominant intermediate product (26.7%). NO₂⁻ and NH₄⁺ accumulated during the process could be further removed through anaerobic ammonium oxidation. Thiocyanate sulfur was primarily oxidized to sulfate via elemental sulfur as a transient intermediate. These findings provide a theoretical basis for applying thiocyanate-driven partial autotrophic denitrification to nitrogen removal from industrial wastewaters, particularly those generated via coal gasification and cyanide-utilizing gold mining processes. Full article

The anammox technology, as an efficient and energy-saving denitrification method, has been widely used in the field of wastewater treatment. Nevertheless, this process faces two key challenges in actual operation, namely the fluctuation of nitrite substrate supply and the residual nitrate, which greatly limits its promotion and application in a wider range. Although the traditional combined process of partial denitrification/anammox (PD/A) can generate nitrite substances, the coexistence of heterotrophic microorganisms and organic carbon sources in the system may have a significant inhibitory effect on the proliferation of Anammox bacteria. The sulfur-oxidizing bacteria (SOB) involved in the sulfur autotrophic denitrification process (SAD) have overlapping ecological niches with Anammox microorganisms and have stable nitrite enrichment characteristics. In view of this, sulfur-oxidizing bacteria are regarded as a potential candidate for combining with the Anammox process. However, the denitrification efficiency of this process is often restricted by the low solubility and poor bioavailability of substrates. At the same time, there are significant research gaps and data deficiencies regarding the key operating parameters for autotrophic short-range denitrification using elemental sulfur to achieve nitrite accumulation and the coupling application of this process with other wastewater treatment technologies. In view of this, this study is committed to comprehensively sorting out and evaluating the existing optimization methods of the elemental sulfur autotrophic denitrification process, while providing an in-depth analysis of its mechanism of action and environmental control factors. At the same time, this study also carried out innovative exploration on the modification process of the sulfur element from the frontier perspective of materials science and pointed out the key directions for subsequent optimization of the construction path of the elemental sulfur autotrophic denitrification system and for improving the denitrification process efficiency. In summary, this study systematically discusses the mechanism of action, practical application, and improvement scheme of PS⁰AD. Full article

Pursuing the so-defined biorefinery approach, residual biomass, such as agro-industrial wastes, should first be exploited for the extraction and production of high-value-added products and then processed for energy valorisation through anaerobic digestion (AD). However, the treatments applied to achieve the first goal could impact biogas yield. This problem can be solved by co-digesting the treated biomass with others. In this study, Brewery’ Spent Grain (by itself, a good biogas producer) was treated with an ionic liquid (IL) composed of triethylamine and sulfuric acid [TEA][HSO₄] for lignin removal. The residual biomass (pulp, BSGp) was then used for biogas production. The tests revealed a marked reduction in the total quantity of biomethane (per unit of volatile solid—VS). In detail, 6.82 × 10⁻⁴ Nm³CH₄/gVS of biomethane was produced with BSGp, against 1.31 × 10⁻³ Nm³CH₄/gVS with BSG. The lack of organic nitrogen after the IL-based treatment prevented biogas production, resulting in a shorter production period. To compensate for the nitrogen deficiency and restore the optimal C/N ratio, BSGp was mixed with Lemna minor (LM), an aquatic weed with a high nitrogen content. By itself, LM cannot be considered a good biogas producer as proven in this study. However, the co-digestion of LM with BSGp extended the production period and kept the daily production close to that registered in test made with the sole BSGp, thus achieving a total biomethane production equal to 1.83 × 10⁻³ Nm³CH₄/gVS, even higher than the one registered with untreated BSG. Full article

Molybdenum disulfide (MoS₂) films are promising solid lubricants for aerospace and other advanced applications, yet their tribological performance is highly sensitive to environmental conditions. To enhance environmental adaptability, Zr-doped MoS₂ composite films were prepared by magnetron co-sputtering, and their composition, microstructure, mechanical properties, and tribological behavior were systematically investigated. The results showed that the as-deposited MoS₂ films exhibited a nearly stoichiometric sulfur-to-molybdenum ratio (S/Mo ≈ 2), while the Zr-doped MoS₂ composite films showed sulfur-deficient, sub-stoichiometric ratios (S/Mo < 2). Pure MoS₂ films displayed a porous columnar structure, whereas with the incorporation of Zr, the columnar structure becomes progressively more compact. Moreover, the film structure transitions from a purely crystalline form to a two-phase structure with both crystalline and amorphous phases coexisting. The hardness and elastic modulus of the films increased with the addition of Zr, mainly due to the densification of the structure and the disorder introduced in the film. Moderate Zr doping markedly improved the friction and wear performance of composite films across vacuum, atmospheric, and humid environments. The optimal film achieved a coefficient of friction (COF) of 0.02 and wear rate of 6.23 × 10⁻⁸ mm³/N·m in vacuum and COFs of 0.10 with low wear rates in both atmospheric and humid conditions. By adjusting the Zr target power to modulate Zr content, the crystallographic orientation and microstructure of MoS₂-Zr composite films could be tailored, thereby regulating their mechanical and tribological properties. This study provides theoretical guidance for the application of metal-doped MoS₂ composite films under alternating environmental conditions. Full article

Sulfur-based autotrophic denitrification (SAD) is limited by low efficiency and poor stability in carbon-deficient photovoltaic (PV) wastewater treatment. This study developed four sulfur-based composite fillers (S⁰-CFs) comprising 75% elemental sulfur and mineral additives (boron mud, magnesite, and/or siderite) fabricated via melt mixing–jet granulation. Lab-scale operation showed that at a hydraulic retention time (HRT) of 1 h, all S⁰-CFs achieved high TN removal (89.1–93.8%) with effluent NO₃⁻-N below 1.5 mg/L (>93% nitrate removal efficiency) and stable pH. Although effluent COD increased with a short HRT (1 h) due to biofilm detachment, no leaching of organic or inorganic pollutants from the fillers was observed, and TP was consistently removed. 16S rRNA sequencing confirmed enrichment of autotrophic denitrifiers Thiobacillus and Sulfurimonas, verifying SAD as the dominant pathway. In a 270-day pilot-scale operation, nitrate removal varied with temperature (7.3–27.2 °C) and HRT, reaching 88.2% on average (range: 86.6–90.0%) at 1 h HRT during warm periods (25.8–27.2 °C), dropping to 13.5–38.1% under cold conditions (7.3–16.0 °C) at 0.5 h HRT, and then stabilizing at 64.1% by adjusting HRT to 1 h. Fluoride was removed at 0.51–1.49 mg/L. Additionally, operational cost was 34.5% lower than heterotrophic denitrification. These results demonstrated that S⁰-CF enabled efficient, stable, and cost-effective nitrogen removal, making SAD more suitable for low-carbon industrial wastewater treatment. Full article

Rice (Oryza sativa L.) readily accumulates cadmium (Cd), posing dietary exposure risks in populations dependent on rice-based diets. This study investigated how sulfur (S) redox processes regulate Cd mobility in S-deficient, Cd-contaminated paddy soil under waterlogged conditions. A pot experiment was conducted with two S treatments (−S and +S, 30 mg kg⁻¹) throughout the rice growing season. S addition markedly increased pore water S²⁻ concentrations during early growth (tillering) and mid-season (booting) and suppressed the diffusion of SO₄²⁻ from non-rhizosphere to rhizosphere at later stages (filling–maturity). Consequently, Cd in soil pore water was significantly lower in +S than −S treatments at all stages. Sulfur-amended soil showed a redistribution of Cd from labile fractions (exchangeable and carbonate-bound) to more stable fractions (Fe/Mn oxide-bound). Sulfur application also altered the rhizosphere microbiome: the relative abundance of sulfate-reducing bacteria (SRB) increased at the booting and filling stages, while sulfur-oxidizing bacteria (SOB) became more dominant at maturity. Additionally, +S enhanced Cd sequestration on rice root iron plaque by 32–67% during the grain-filling and maturity stages compared to −S. Throughout the rice growing period, redox-driven shifts in the S²⁻/SO₄²⁻ ratio emerged as a key control on Cd behavior, with low pe + pH (strongly reducing conditions) promoting Cd sulfide precipitation and high pe + pH (more oxidizing conditions) causing Cd remobilization. Full article