Sulfur Research Articles

Understanding the Dynamics of Sulfur Droplets Formation in Lean-Electrolyte and Low-Temperature Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) afford great promises as the next-generation rechargeable batteries due to the high energy density and low cost of sulfur cathodes. Lean-electrolyte condition constitutes the prerequisite for high-energy LSBs, but the insulating sulfur particles hinder capacity utilization, especially at low temperatures. Here, the electrochemical generation of liquid sulfur droplets in the LSB system are studied and elucidate the polysulfide oxidation reaction (SOR) kinetics under different electrolyte/sulfur (E/S) ratios and low-temperature conditions. The real-time observations under in situ optical and Raman microscopies indicate that the formation of liquid sulfur during SOR is independent of the E/S ratio and can be preserved over a wide range of operating temperatures. Quantification of the polysulfide reactant concentrations and the amounts of the liquid sulfur product under different charging conditions reveal pseudo-zero-order kinetics and E/S ratio-dependent reaction constants for the SOR process. In addition, under extreme conditions of -20°C and E/S ratio of 5µLmg-1, liquid sulfur can still be preserved by following the rapid SOR kinetics. These findings provide new insights into the liquid sulfur generation dynamics in Li─S chemistry, which enables a deeper understanding of the effects of the E/S ratio and working temperature on the oxidation kinetics in LSBs.

Integrating genomic evidence for an updated taxonomy of the bacterial genus Spiribacter

The genus Spiribacter encompasses halophilic bacteria widely distributed in hypersaline environments worldwide. Despite their ecological significance, initially isolating Spiribacter species under laboratory settings was challenging due to the lack of knowledge of their growth and cultivation requirements. However, with improved understanding of their ecological niche and metabolic pathways, additional species of Spiribacter have been successfully isolated and identified from diverse locations around the globe. Enriched media with sodium pyruvate as carbon source facilitated the isolation of twelve new strains closely related to the genus Spiribacter from hypersaline environments in Spain. Genome sequencing and analysis of these new strains and previously described Spiribacter species provided insights into their genomic features and phylogenomic relationships, supporting the delineation of three distinct new species within this genus, designated as Spiribacter insolitus sp. nov., Spiribacter onubensis sp. nov., and Spiribacter pallidus sp. nov. In Spiribacter species, streamlined genomes enhance survival in hypersaline environments by reducing non-essential genes and optimizing resource utilization. Key genes involved in osmoprotectant mechanisms, including those for the metabolism of myo-inositol, hydroxyproline, and L-proline, were identified and numerous transporters were noted, ensuring efficient nutrient acquisition and osmotic balance. Notably, these new species, along with other Spiribacter strains, exhibit metabolic diversity in utilizing inorganic sulfur compounds, including thiosulfate and tetrathionate, for energy production and adaptation to hypersaline environments. The presence of thiosulfate dehydrogenase (TsdA) genes suggests their capability to oxidize thiosulfate to tetrathionate, potentially influencing both aerobic and anaerobic respiration. Furthermore, the prevalence of the sqr gene indicates a role for sulfide oxidation in Spiribacter metabolism, underlining their metabolic versatility in saline habitats. These adaptations allow Spiribacter to thrive in nutrient-limited, high-salinity habitats. Moreover, genome mining analysis and physiological disparities observed in the already described species Spiribacter halobius raise significant challenges to its classification within the genus Spiribacter.

Effects of exogenous selenium application on quality characteristics, selenium speciation, and in vitro bioaccessibility of rice pancakes

Selenium is an essential trace element for human health. To date, a hotspot of functional foods is strengthening the content of organic Se in food using biological Se enrichment. Herein, Se-enriched rice pancakes were produced by directly adding different sodium selenite concentrations into the fermentation process. The effects of sodium selenite addition on the texture properties, structure, and Se species of rice pancakes were investigated. Meanwhile, the bioaccessibility of Se and the changes of Se species in Se-enriched rice pancakes were determined by digestion experiments in vitro. The results showed significant differences in hardness, adhesiveness, chewiness, porosity, and flavor substances of Se-enriched rice pancakes after adding sodium selenite (p < 0.05). In Se-enriched rice pancakes, selenocystine (SeCys2) and methylselenocysteine (MeSeCys) are the main Se species. When sodium selenite was added at 3.3 μg/ml, the maximum values of SeCys2 and MeSeCys were 328.35 ± 33.43 and 311.11 ± 49.48 μg/kg, respectively. Se bioaccessibility was negatively correlated with sodium selenite content. The electronic nose results of Se-enriched rice pancakes showed that the sulfur compounds, nitrogen substances, alcohol substances, alkane substances, alcohols, aldehydes, and ketones in rice pancakes significantly increased following sodium selenite addition. The results can provide a significant basis for developing high efficiency Se-enriched fermented food and the processing of Se-enriched rice pancakes.

S-allylmercaptocysteine inhibits TLR4-mediated inflammation through enhanced formation of inhibitory MyD88 splice variant in mammary epithelial cells

Mastitis is an inflammatory disease affecting mammary tissues caused by bacterial infection that negatively affects milk quality and quantity. S-Allylmercaptocysteine (SAMC), a sulfur compound in aged garlic extract (AGE), suppresses lipopolysaccharide (LPS)-induced inflammation in mouse models and cell cultures. However, the mechanisms underlying this anti-inflammatory effect remain unclear. In this study, we demonstrated that oral administration of AGE suppressed the LPS-induced immune response in a mastitis mouse model and that SAMC inhibited LPS-induced interleukin-6 production and nuclear factor κB p65 subunit activation in HC11 mammary epithelial cells. Global phosphoproteomic analysis revealed that SAMC treatment downregulated 910 of the 1,304 phosphorylation sites upregulated by LPS stimulation in mammary cells, including those associated with toll-like receptor 4 (TLR4) signaling. Additionally, SAMC decreased the phosphorylation of 26 proteins involved in pre-mRNA splicing, particularly the U2 small nuclear ribonucleoprotein complex. Furthermore, we found that SAMC increased the production of the myeloid differentiation factor 88 short form (MyD88-S), an alternatively spliced form of MyD88 that negatively regulates TLR4 signaling. These findings suggest that SAMC inhibits TLR4-mediated inflammation via alternative pre-mRNA splicing, thus promoting MyD88-S production in mammary epithelial cells. Therefore, SAMC may alleviate various inflammatory diseases, such as mastitis, by modulating immune responses.

TREATMENT OF EFFLUENTS OF TEXTILE INDUSTRIES TO REDUCE POLLUTANTS INGRESS INTO SURFACE WATERS

Technological schemes of processing textile materials with special chemicals are considered. A method of reducing the concentration of heavy metal ions in waste water of textile manufacturing enterprises based on the combination of effluents from different technological lines is proposed. To reduce the degree of oxidation of chromium (Cr6+ to Cr3+), as well as to transfer salts of copper, cobalt, nickel and other metals from a liquid to a solid state, it is recommended to mix such wastewater with effluents containing sodium or potassium sulfide. The method can be used at enterprises of the chemical, printing, and paint industries. To reduce the content of sulfides of various metals in wastewater and obtain colloidal sulfur, a method of oxidation of such salts by ozonation using a special ozonator is proposed. Ozonation also makes it possible to reduce the content of organic substances in the total volume of effluents to standardized indicators.

Ammonia Emissions from Swiss Agriculture and their Effects on Atmospheric Chemistry and Ecosystems

Ammonia (NH3) is an important atmospheric pollutant due to its contribution to secondary inorganic aerosol formation and its deposition and impacts on (semi-)natural ecosystems. Therefore various efforts have been made to limit emissions to the atmosphere. The predominant emission source in Switzerland is livestock agriculture, wherein NH3 is volatilised from ammonium contained in animal manure. While modelled NH3 emissions based on agricultural activity data indicate a minor decrease since 2000, concentration measurements do not reflect this trend. This can at least partly be attributed to a decline in the transformation of NH3 to particulate ammonium due to significantly decreased emission of oxidised nitrogen and sulfur compounds in the past decade. The partitioning between the gaseous and the particulate phase also determines the deposition pathway (dry or wet deposition) and thus the average lifetime and transport distance in the atmosphere. Gaseous NH3 is subject to fast dry deposition and is deposited preferentially to ecosystems close to the source. Once deposited into an ecosystem, NH3 leads to eutrophication and acidification of water and soils, which change the plant community composition and microbial functioning, especially in N-sensitive ecosystems. Although NH3 can also cause direct toxicity to plants, assessments of ecosystem impacts are generally collated using the critical load approach, which includes the input of all N compounds. These reveal that in 2020, 87% of forests, 94% of raised bogs, 74% of fens, and 42% of dry mountain grasslands likely experienced adverse impacts from N exceedances in Switzerland. To improve this situation, considerable NH3 emission abatement efforts are needed in the future.

From Biofilm to Breath: The Role of Lacticaseibacillus paracasei ET-22 Postbiotics in Combating Oral Malodor.

Previous studies demonstrated that sufferers with halitosis can be significantly improved with Lacticaseibacillus paracasei ET-22 (ET-22) postbiotics intervention. The objectives of this investigation were to identify the primary components responsible for inhibiting oral malodor. This study demonstrated that cell-free supernatants (CFSs) were more effective in inhibiting production of volatile sulfur compounds (VSCs). Untargeted metabolomics identified CFSs as primarily consisting of organic acids, lipids, peptides, and nucleotides. Among the potential active components, phenyllactic acid (PLA) and peptide GP(Hyp)GAG significantly inhibited microbial-induced VSCs production, with VSC concentrations reduced by 42.7% and 44.6%, respectively. Given the correlation between biofilms and halitosis, microstructural changes in biofilms were examined. PLA suppressed the biomass of the biofilm by 41.7%, while the biofilm thickness was reduced from 202.3 to 70.0 μm. GP(Hyp)GAG intervention reduced the abundance of Fusobacterium nucleatum and Streptococcus mutans within the biofilm, and the expression of biofilm-forming genes FadA and Gtfb were also suppressed by 41.8% and 59.4%. Additionally, the VSC production capacities were reduced due to the decrease in VSC producing bacteria (F. nucleatum, Prevotella intermedia, and Solobacterium moorei) and down-regulation of Cdl and Mgl genes. Collectively, the current study proved that PLA and GP(Hyp)GAG may be the main contributors to halitosis inhibition by ET-22 postbiotics.

Sulfur in Tephra of Opala Volcano Eruption ca. 1500 years ago, Kamchatka

Sulfur-bearing compounds of Plinian-type volcanic eruptions can be transferred with ash particles of distal tephra over considerable distances. Average sulfur content in tephra of Opala volcano (Kamchatka, eruption ca. 1500 years ago) comprises 310 ppm with maximum concentration up to 800 ppm. Connection detected between sulfur content in bulk samples and the particle size distribution – sulfur is predominantly contained in the fraction 0.25‒0.50 mm represented by elongated ash particles with elongated gas pores 1.0‒10.0 mkm in diameter. The most likely reason for the dependence of sulfur content on the texture of ash particles is preservation of sulfur compounds of the water-soluble complex inside gas pores. Sulfur-containing compounds deposited on the surface of ash particles were removed by precipitation in the process of existing tephra in continental environment. Ingress of ash particles into bottom sediments containing sulfur compounds on the inner surface of gas pores during plinian type eruptions similar to the eruption of Opala volcano ca. 1500 years ago, may influence the geochemistry of lithogenesis and lead to redistribution of elements sensitive to the presence of acid-forming agents in the sediment at the stage of diagenesis.

Effectiveness of a combination of laccase and green coffee extract on oral malodor: a comparative, randomized, controlled, evaluator-blind, parallel-group trial

Oral malodor negatively impacts a person's quality of life and may affect up to 50% of the population. The aim of this randomized, placebo and no-product controlled, evaluator-blind, proof-of-concept study was to evaluate the effectiveness and safety of the single use of two experimental lozenges containing the laccase enzyme and green coffee extract (with and without flavor) in reducing intrinsic oral malodor. Following 12-16 h of avoidance of oral hygiene,156 generally healthy subjects presented at screening and baseline visits with a mean organoleptic odor intensity (OI) score of ⩾2 and an OralChromaTMreading of ⩾125 parts per billion (ppb) hydrogen sulfide (H2S) gas and were randomly assigned to receive either one of the two experimental lozenges, a placebo lozenge, or no-product. Following the supervised use of the assigned products, subjects' oral malodor was evaluated using OI assessments and OralChromaTMmeasurement for volatile sulfur compounds (VSCs) immediately following product use (approximately 5 min), and at 30 min, 1 h, 2 h, 3 h and 4 h. The two experimental lozenges, with and without flavor, showed significant reductions in OI scores compared with the placebo and no-product groups at all time points (p< 0.001). At 5 min post-product use, the experimental lozenges, with and without flavor, were significantly better than the no-product group in reducing the VSCs (p< 0.04). The results of individual VSC components (hydrogen sulfide, methyl mercaptan and dimethyl sulfide) were variable; both experimental lozenges notably reduced hydrogen sulfide and methyl mercaptan levels in most post-use assessments. Four minor adverse events were reported, none of which were directly linked to the product. In conclusion, the experimental lozenges, whether flavored or not, were safe and effective in reducing oral malodor over a span of 4 h, based on organoleptic OI scores.Clinical Trial No: NCT05950529.

Innovative research on one-step regeneration and reduction of saturated desulfurization coke: Reactivating desulfurization performance and sulfur recovery

Current advancements in flue gas desulfurization have highlighted the efficacy of activated coke (AC) as an SO2 adsorbent, leveraging sulfur resources. Despite its success, challenges such as lengthy processing and logistics for sulfuric acid storage and transport limit its widespread use. This research explores an innovative approach: powder saturated AC (SAC) achieves rapid temperature rise and one-step regeneration coupled reduction in a drop-tube reactor. Findings reveal that SAC undergoes primary regeneration at 450–650 ℃, converting adsorbed sulfur compounds into gaseous SO2. However, issues like incomplete active site recovery and surface oxidation reduce the re-adsorption capacity of regenerated AC. At 750–950 ℃, a concurrent regeneration and reduction phase converts desorbed SO2 into elemental sulfur. Carbothermal reduction during this phase enhances microporous structure development, lowers oxygen content, increases edge defects, promotes sulfur doping, and boosts SO2 re-adsorption efficiency. This study provides practical insights and a conceptual framework to refine desulfurization processes and optimize resultant products.

Sulfur-functionalized rice straw biochar for enhanced cadmium sorption: Spectroscopic, kinetic and computational insights

Cadmium (Cd) contamination necessitates effective remediation approaches. This study valorizes rice straw biochar by enhancing its Cd sorption capacity through sulfur functionalization. Biochar was functionalized with sulfur compounds (H2SO4, Na2S, and Na2S2O3) to introduce Lewis soft base characteristics for improved affinity towards Cd(II), a Lewis soft acid. Characterization confirmed successful grafting of various sulfur groups, increasing the sulfur content from 0.33% to 13.27% and boosting oxygen-containing functional groups. The sulfur-functionalized biochar demonstrated significantly enhanced Cd(II) sorption compared to pristine biochar, with a maximum capacity of 34.40 mg g−1 at pH 5.0 – a 17.3-fold increase – and reduced equilibrium time from 8 h to 5–10 min. Density functional theory calculations suggested that sulfur doping facilitated Cd-S bond formation and modulated the electronic properties of the biochar-Cd systems, contributing to the superior sorption performance. Sulfur functionalization offers a cost-effective, eco-friendly method for enhanced Cd(II) removal, validated by experiments and theory.

YeeE-like bacterial SoxT proteins mediate sulfur import for oxidation and signal transduction

Many sulfur-oxidizing prokaryotes oxidize sulfur compounds through a combination of initial extracytoplasmic and downstream cytoplasmic reactions. Facultative sulfur oxidizers adjust transcription to sulfur availability. While sulfur-oxidizing enzymes and transcriptional repressors have been extensively studied, sulfur import into the cytoplasm and how regulators sense external sulfur are poorly understood. Addressing this gap, we show that SoxT1A and SoxT1B, which resemble YeeE/YedE-family thiosulfate transporters and are encoded alongside sulfur oxidation and transcriptional regulation genes, fulfill these roles in the Alphaproteobacterium Hyphomicrobium denitrificans. SoxT1A mutants are sulfur oxidation-negative despite high transcription levels of sulfur oxidation genes, showing that SoxT1A delivers sulfur to the cytoplasm for its further oxidation. SoxT1B serves as a signal transduction unit for the transcriptional repressor SoxR, as SoxT1B mutants are sulfur oxidation-negative due to low transcription unless SoxR is also absent. Thus, SoxT1A and SoxT1B play essential but distinct roles in oxidative sulfur metabolism and its regulation.

State of the Art and Challenges in Complete Benzene Oxidation: A Review.

Increased levels and detrimental effects of volatile organic compounds (VOCs) on air quality and human health have become an important issue in the environmental field. Benzene is classified as one of the most hazardous air pollutants among non-halogenated aromatic hydrocarbons with toxic, carcinogenic, and mutagenic effects. Various technologies have been applied to decrease harmful emissions from various sources such as petrochemistry, steel manufacturing, organic chemical, paint, adhesive, and pharmaceutical production, vehicle exhausts, etc. Catalytic oxidation to CO2 and water is an attractive approach to VOC removal due to high efficiency, low energy consumption, and the absence of secondary pollution. However, catalytic oxidation of the benzene molecule is a great challenge because of the extraordinary stability of its six-membered ring structure. Developing highly efficient catalysts is of primary importance for effective elimination of benzene at low temperatures. This review aims to summarize and discuss some recent advances in catalyst composition and preparation strategies. Advantages and disadvantages of using noble metal-based catalysts and transition metal oxide-based catalysts are addressed. Effects of some crucial factors such as catalyst support nature, metal particle size, electronic state of active metal, redox properties, reactivity of lattice oxygen and surface adsorbed oxygen on benzene removal are explored. Thorough elucidation of reaction mechanisms in benzene oxidation is a prerequisite to develop efficient catalysts. Benzene oxidation mechanisms are analyzed based on in situ catalyst characterization, reaction kinetics, and theoretical simulation calculations. Considering the role of oxygen vacancies in improving catalytic performance, attention is given to oxygen defect engineering. Catalyst deactivation due to coexistence of water vapor and other pollutants, e.g., sulfur compounds, is discussed. Future research directions for rational design of catalysts for complete benzene oxidation are provided.

Physicochemical properties, GC–MS profiling, and antibacterial potential of Allium sativum essential oil: In vitro and in silico approaches

Antibiotic resistance remains a critical challenge for public health. In this study, we investigate the antibacterial potential of Moroccan Allium sativum L. essential oil (EO) through both in vitro and in silico approaches. The EO was extracted using hydrodistillation, and its physicochemical properties were analyzed alongside its chemical composition via gas chromatography-mass spectrometry (GC/MS). We assessed antibacterial efficacy through disk diffusion assays targeting Escherichia coli (E. coli), methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa (P. aeruginosa), and determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Finally, an in silico molecular docking analysis and ADMET (absorption, distribution, metabolism, excretion, and toxicity) prediction were performed. Our analysis identified 13 sulfur-based compounds within the EO, with diallyl disulfide (42.85 %), methylallyl disulfide (18.84 %), methylallyl trisulfide (15.38 %), and diallyl trisulfide (13.11 %) as major constituents. The EO demonstrated robust activity against MRSA, with an inhibition zone of 22 mm and an MIC of 0.75 mg/mL, whereas E. coli exhibited lower sensitivity, with an MIC of 1.51 mg/mL. Molecular docking analysis suggested that the primary sulfur compounds may effectively inhibit bacterial resistance-related enzymes. These findings highlight the potential of Allium sativum L. EO as a natural antibacterial agent, attributed largely to its sulfur compound content. This activity is likely linked with the EO's interaction with the complex structures of bacterial cell membranes, offering promise in combating resistant bacterial strains.

Recent Advances of C-S Coupling Reaction of (Hetero)Arenes by C-H Functionalization.

Organic sulfur compounds encompass a vast and diverse variety of species that possess unique biological activity due to the presence of sulfur atoms or sulfur-containing functional groups. These compounds are widely present in natural products, pharmaceuticals, agricultural chemicals, and functional materials. In recent years, numerous sulfur-containing compounds such as thiols, thioethers, disulfides, thiourea, dimethyl sulfoxide, sulfonates and their derivatives, as well as sulfur-containing inorganic compounds, have been utilized as coupling agents to synthesize (hetero)aryl sulfides via C-H Functionalization. These novel transformations provide effective methods for constructing C-S bond of (hetero)arenes, while also expanding the scope of (hetero)aryl sulfides with the potential biological activity. Therefore, the synthesis of aryl sulfides through C-H bond functionalization has attracted widespread attention. This review mainly focuses on the construction of (hetero)aryl sulfides via C-H bond functionalization since 2015. We hope this review offers a useful conceptual overview and inspires further advancements in the efficient construction of C-S bonds.

Effects of jogi, Micropogonias undulatus, addition on the production of volatile compounds in baechu-kimchi.

Baechu-kimchi is a traditional vegetable fermented food using kimchi cabbage (Brassica rapa) as the main ingredient. A wide variety of ingredients can be used in kimchi depending on the specific region and even household. Although there have been a lot of studies examining various aspects of kimchi, there has been limited research on kimchi with added fish as a minor ingredient. Therefore, in the present work we aimed to assess changes in the volatile compounds of baechu-kimchi with the addition of seafood used as minor ingredients of kimchi. Sulfur compounds were the most commonly detected volatile compounds; 9 categories of volatile components were detected in total. Altogether, 30 sulfur compounds were detected, and among them, five sulfur compounds: (E)-1-(methyltrisulfanyl)prop-1-ene, 1-(methyldisulfanyl)-1-methylsulfanylpropane, (methyltetrasulfanyl)methane, 1-(methyldisulfanyl)-1-[(E)-prop-1-enyl]sulfanylpropane, and 1,1-bis(methyldisulfanyl)propane, were found only in jogi-added kimchi, thus confirming the influence of jogi addition. Principal component analysis revealed clear distinctions in the volatile compounds as a result of jogi addition as fermentation progressed. Moreover, when confirming the correlation with microbial populations, it was evident that the differentiation in volatile compounds was more attributable to jogi addition than microbial impact. In conclusion, the addition of jogi to baechu-kimchi led to an abundance of volatile compounds by the 20th day of fermentation.

Synthesis of Sulfinamidines via Iron-Catalyzed Nitrene Transfer Reaction with Sulfenamides.

An iron-catalyzed nitrene transfer reaction for the rapid synthesis of sulfinamidines from readily available sulfenamides is reported. This method features mild conditions, short reaction times, and a broad substrate scope, allowing the preparation of a variety of sulfinamidines in good to excellent yields. The synthetic utility of the sulfinamidine products was further demonstrated through their conversion to other valuable sulfur(VI) compounds, such as sulfondiimidoyl fluorides, sulfinamidiate esters, and sulfonimidamides. Preliminary efforts in the development of an asymmetric variant showed moderate enantioselectivity.

Rhodobacteraceae are Prevalent and Ecologically Crucial Bacterial Members in Marine Biofloc Aquaculture.

Bioflocs are microbial aggregates primarily composed of heterotrophic bacteria that play essential ecological roles in maintaining animal health, gut microbiota, and water quality in biofloc aquaculture systems. Despite the global adoption of biofloc aquaculture for shrimp and fish cultivation, our understanding of biofloc microbiota-particularly the dominant bacterial members and their ecological functions-remains limited. In this study, we employed integrated metataxonomic and metagenomic approaches to demonstrate that the family Rhodobacteraceae of Alphaproteobacteria consistently dominates the biofloc microbiota and plays essential ecological roles. We first analyzed a comprehensive metataxonomic dataset consisting of 200 16S rRNA gene amplicons collected across three Asian countries: South Korea, China, and Vietnam. Taxonomic investigation identified Rhodobacteraceae as the dominant and consistent bacterial members across the datasets. The predominance of this taxon was further validated through metagenomics approaches, including read taxonomy and read recruitment analyses. To explore the ecological roles of Rhodobacteraceae, we applied genome-centric metagenomics, reconstructing 45 metagenome-assembled genomes. Functional annotation of these genomes revealed that dominant Rhodobacteraceae genera, such as Marivita, Ruegeria, Dinoroseobacter, and Aliiroseovarius, are involved in vital ecological processes, including complex carbohydrate degradation, aerobic denitrification, assimilatory nitrate reduction, ammonium assimilation, and sulfur oxidation. Overall, our study reveals that the common practice of carbohydrate addition in biofloc aquaculture systems fosters the growth of specific heterotrophic bacterial communities, particularly Rhodobacteraceae. These bacteria contribute to maintaining water quality by removing toxic nitrogen and sulfur compounds and enhance animal health by colonizing gut microbiota and exerting probiotic effects.

Halitosis in oral lichen planus patients

To investigate the halitosis level in oral lichen planus (OLP) patients and OLP-free participants. This cross-sectional study recruited 70 participants at the New Zealand's National Centre for Dentistry. Halitosis was determined using the objective measurements (parts per billion (ppb) volatile sulphur compounds (VSCs) in the exhaled air) and subjective measurement (self-reported halitosis questionnaire). The VSCs values of OLP participants (mean ± SD: 144.64 ± 23.85 ppb) were significantly greater than that in the OLP-free participants (105.52 ± 22.31ppb) (mean difference: 39.12 ppb;p< 0.05; 95% CI: 27.95, 50.29). The VSCs value of hyperplastic (mean difference: 34.11; 95% CI: 20.07, 48.15;p< 0.05) and erosive/ulcerative (mean difference: 57.47; 95% CI: 34.19, 80.76;p< 0.05) OLP participants were statistically greater than that of OLP-free participants. No statistical significance was found between hyperplastic and erosive/ulcerative OLP (p> 0.05). 'Type (OLP-free/OLP)' has a significant effect on the dependent variable VSCs. 78.6% of OLP and 90.5% of OLP-free brushed their teeth at least twice daily, with a statistically significant observation (Mean square: 1.61; F: 13.13;p< 0.05). The levels of VSCs were greater in participants with hyperplastic and erosive/ulcerative OLP than that in the OLP-free participants.

Determination of the gas-liquid reaction kinetic for sulfur dioxide absorption in sodium chlorite aqueous solutions

This study is part of the research activities devoted to the development of new gas-cleaning technologies required to minimize the emissions factors of sulfur compounds in chemical industries and power plants. Among flue gas desulfurization (FGD) processes, wet scrubbing with oxidizing chemicals, e.g. sodium chlorite (NaClO2) has appeared as a viable option for different applications. The present work aims to study the absorption kinetics of the gas-liquid reaction between sulfur dioxide (SO2) and NaClO2, in a lab-scale falling-film absorber, investigating the effects of the main process parameters: liquid and gas flow rates, SO2 gas-phase concentration, NaClO2 liquid-phase concentration, solution pH and process temperature. The experimental activity aims to determine the Enhancement Factor (EL) to develop a kinetic model for reactive absorption. To this end, kinetic parameters are calculated from experiments using the Danckwerts equation for a pseudo-second-order reaction kinetic, determining a maximum prediction error of ±20% compared to the experimental data. Experimental data available in the literature on pilot-scale oxidative FGD scrubbers using chlorite are used to test the validity and robustness of the kinetic model. The kinetic model is able to predict the data with good accuracy within a prediction error range of ±30%.