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The chemical engineering community has shown significant interest in investigating methods to decompose hydrogen sulfide into hydrogen and sulfur. However, there is still a lack of detailed experimental data enabling us to choose the optimal catalyst, reaction, and regeneration conditions, as well as the overall process design. The purpose of this work is to synthesize a series of catalysts and compare their catalytic activity under the same conditions, chosen on the basis of a possible large-scale H2S conversion process. To achieve this, the obtained catalysts were characterized by BET, XRD, SEM, TEM, and XPS before and after the reaction. Decomposition was conducted in a laboratory fixed-bed reactor at a temperature of 500 °C, 10 vol% of H2S in the feed, and a GHSV of 540–1000 h−1. DFT calculations evaluated the H2S bond cleavage on various catalyst surfaces. It was shown that the most promising catalyst was Ni3S2, offering an acceptable H2S conversion of 40%. We also observed that Ni3S2 catalyst regeneration could be conducted at much milder conditions compared to those previously reported in the literature. These results highlight the viability of upscaling the process with the selected catalyst. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) is a highly toxic and corrosive gas commonly found in industrial emissions and natural gas processing, posing serious risks to human health and environmental safety even at low concentrations. The early detection of H2S is therefore critical for preventing accidents and ensuring compliance with safety regulations. This study presents the development of porous ZnO/SnO2-nanocomposite gas sensors tailored for the ultrasensitive detection of H2S at sub-ppb levels. Utilizing a screen-printing method, we fabricated five different sensor compositions—ranging from pure SnO2 to pure ZnO—and characterized their structural and morphological properties through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Among these, the SnO2/ZnO sensor with a composition-weight ratio of 3:4 demonstrated the highest response at 325 °C, achieving a low detection limit of 0.14 ppb. The sensor was evaluated for detecting H2S concentrations ranging from 5 ppb to 500 ppb under dry, humid air and N2 conditions. The relative concentration error was carefully calculated based on analytical sensitivity, confirming the sensor's precision in measuring gas concentrations. Our findings underscore the significant advantages of mixture nanocomposites in enhancing gas sensitivity, offering promising applications in environmental monitoring and industrial safety. This research paves the way for the advancement of highly effective gas sensors capable of operating under diverse conditions with high accuracy. [ABSTRACT FROM AUTHOR]

Marginal vitamin B6 (B6) deficiency is common in various segments worldwide. In a super-aged society, sarcopenia is a major concern and has gained significant research attention focused on healthy aging. To date, the primary interventions for sarcopenia have been physical exercise therapy. Recent evidence suggests that inadequate B6 status is associated with an increased risk of sarcopenia and mortality among older adults. Our previous study showed that B6 supplementation to a marginal B6-deficient diet up-regulated the expression of various exercise-induced genes in the skeletal muscle of rodents. Notably, a supplemental B6-to-B6-deficient diet stimulates satellite cell-mediated myogenesis in rodents, mirroring the effects of physical exercise. These findings suggest the potential role of B6 as an exercise-mimetic nutrient in skeletal muscle. To test this hypothesis, we reviewed relevant literature and compared the roles of B6 and exercise in muscles. Here, we provide several pieces of evidence supporting this hypothesis and discuss the potential mechanisms behind the similarities between the effects of B6 and exercise on muscle. This research, for the first time, provides insight into the exercise-mimetic roles of B6 in skeletal muscle. [ABSTRACT FROM AUTHOR]

Many fatal inhalational accidents occurring during construction typically involving confined spaces and structures that confine the atmosphere continue to defy identification. Very little information is available, principally from accident summaries and government reports. Increasingly, these identify CO2 (carbon dioxide) as a probable cause. This article discusses situations identified in accident summaries and worldwide databases. CO2 lacks an odor and other means of identification without the use of monitoring instruments. Emissions typically involve exhaust gases; aerobic and anaerobic respiration in microbiological systems in wastewater and landfills; geological deposits capable of chemical reaction to produce CO2; and unintended discharge from pressurized systems. Emissions can occur continuously or abruptly subject to the type of system and conditions involved. Anaerobic systems that behave as shear-thinning, pseudoplastic, non-Newtonian fluids emit abruptly on the application of a shear force. A lethal concentration can develop almost instantaneously. Upon cessation of the stress, the ambient condition restores rapidly. Chemical and physical processes provide reservoirs for the storage of gas. Very limited methods are available for the prevention of these accidents because of the infrequency and unpredictability of the emission. Preventive measures include mandatory atmospheric monitoring and ventilation at all times, where hazardous conditions can develop, and sometimes the use of high-level respiratory protection. [ABSTRACT FROM AUTHOR]

The kidney is an essential excretory organ that works as a filter of toxins and metabolic by-products of the human body and maintains osmotic pressure throughout life. The kidney undergoes several physiological, morphological, and structural changes with age. As life expectancy in humans increases, cell senescence in renal aging is a growing challenge. Identifying age-related kidney disorders and their cause is one of the contemporary public health challenges. While the structural abnormalities to the extracellular matrix (ECM) occur, in part, due to changes in MMPs, EMMPRIN, and Meprin-A, a variety of epigenetic modifiers, such as DNA methylation, histone alterations, changes in small non-coding RNA, and microRNA (miRNA) expressions are proven to play pivotal roles in renal pathology. An aged kidney is vulnerable to acute injury due to ischemia-reperfusion, toxic medications, altered matrix proteins, systemic hemodynamics, etc., non-coding RNA and miRNAs play an important role in renal homeostasis, and alterations of their expressions can be considered as a good marker for AKI. Other epigenetic changes, such as histone modifications and DNA methylation, are also evident in AKI pathophysiology. The endogenous production of gaseous molecule hydrogen sulfide (H2S) was documented in the early 1980s, but its ameliorative effects, especially on kidney injury, still need further research to understand its molecular mode of action in detail. H2S donors heal fibrotic kidney tissues, attenuate oxidative stress, apoptosis, inflammation, and GFR, and also modulate the renin–angiotensin–aldosterone system (RAAS). In this review, we discuss the complex pathophysiological interplay in AKI and its available treatments along with future perspectives. The basic role of H2S in the kidney has been summarized, and recent references and knowledge gaps are also addressed. Finally, the healing effects of H2S in AKI are described with special emphasis on epigenetic regulation and matrix remodeling. [ABSTRACT FROM AUTHOR]

The action of abscisic acid (ABA) is closely related to its level in plant tissues. Uridine diphosphate-glycosyltransferase71c5 (UGT71C5) was characterized as a major UGT enzyme to catalyze the formation of the ABA-glucose ester (ABA-GE), a reversible inactive form of free ABA in Arabidopsis thaliana (thale cress). UGTs function in a mode where the catalytic base deprotonates an acceptor to allow a nucleophilic attack at the anomeric center of the donor, achieving the transfer of a glucose moiety. The proteomic data revealed that UGT71C5 can be persulfidated. Herein, an experimental method was employed to detect the persulfidation site of UGT71C5, and the computational methods were further used to identify the yet unknown molecular basis of ABA glycosylation as well as the regulatory role of persulfidation in this process. Our results suggest that the linker and the U-shaped loop are regulatory structural elements: the linker is associated with the binding of uridine diphosphate glucose (UPG) and the U-shaped loop is involved in binding both UPG and ABA.It was also found that it is through tuning the dynamics of the U-shaped loop that is accompanied by the movement of tyrosine (Y388) that the persulfidation of cysteine (C311) leads to the catalytic residue histidine (H16) being in place, preparing for the deprotonation of ABA, and then reorientates UPG and deprotonated ABA closer to the 'Michaelis' complex, facilitating the transfer of a glucose moiety. Ultimately, the persulfidation of UGT71C5 is in favor of ABA glycosylation. Our results provide insights into the molecular details of UGT71C5 recognizing substrates and insights concerning persulfidation as a possible mechanism for hydrogen sulfide (H2S) to modulate the content of ABA, which helps us understand how modulating ABA level strengthens plant tolerance. [ABSTRACT FROM AUTHOR]

Vitamin D receptors are expressed in many organs and tissues, which suggests that vitamin D (VD) affects physiological functions beyond its role in maintaining bone health. Deficiency or inadequacy of 25(OH)VD is widespread globally. Population studies demonstrate that a positive association exists between a high incidence of VD deficiency and a high incidence of chronic diseases, including dementia, diabetes, and heart disease. However, many subjects have difficulty achieving the required circulating levels of 25(OH)VD even after high-dose VD supplementation, and randomized controlled clinical trials have reported limited therapeutic success post-VD supplementation. Thus, there is a discordance between the benefits of VD supplementation and the prevention of chronic diseases in those with VD deficiency. Why this dissociation exists is currently under debate and is of significant public interest. This review discusses the downregulation of VD-metabolizing genes needed to convert consumed VD into 25(OH)VD to enable its metabolic action exhibited by subjects with metabolic syndrome, obesity, and other chronic diseases. Research findings indicate a positive correlation between the levels of 25(OH)VD and glutathione (GSH) in both healthy and diabetic individuals. Cell culture and animal experiments reveal a novel mechanism through which the status of GSH can positively impact the expression of VD metabolism genes. This review highlights that for better success, VD deficiency needs to be corrected at multiple levels: (i) VD supplements and/or VD-rich foods need to be consumed to provide adequate VD, and (ii) the body needs to be able to upregulate VD-metabolizing genes to convert VD into 25(OH)VD and then to 1,25(OH)2VD to enhance its metabolic action. This review outlines the association between 25(OH)VD deficiency/inadequacy and decreased GSH levels, highlighting the positive impact of combined VD+LC supplementation on upregulating GSH, VD-metabolizing genes, and VDR. These effects have the potential to enhance 25(OH)VD levels and its therapeutic efficacy. [ABSTRACT FROM AUTHOR]

Both melatonin and hydrogen sulfide (H2S) mitigate chromium (Cr) toxicity in plants, but the specific interaction between melatonin and H2S in Cr detoxification remains unclear. In this study, the interaction between melatonin and H2S in Cr detoxification was elucidated by measuring cell wall polysaccharide metabolism and antioxidant enzyme activity in maize. The findings revealed that exposure to Cr stress (100 μM K2Cr2O7) resulted in the upregulation of L-/D-cysteine desulfhydrase (LCD/DCD) gene expression, leading to a 77.8% and 27.3% increase in endogenous H2S levels in maize leaves and roots, respectively. Similarly, the endogenous melatonin system is activated in response to Cr stress. We found that melatonin had a significant impact on the relative expression of LCD/DCD, leading to a 103.3% and 116.7% increase in endogenous H2S levels in maize leaves and roots, respectively. In contrast, NaHS had minimal effects on the relative mRNA expression of serotonin-Nacetyltransferase (SNAT) and endogenous melatonin levels. The production of H2S induced by melatonin is accompanied by an increase in Cr tolerance, as evidenced by elevated gene expression, elevated cell wall polysaccharide content, increased pectin methylesterase activity, and improved antioxidant enzyme activity. The scavenging of H2S decreases the melatonin-induced Cr tolerance, while the inhibitor of melatonin synthesis, p-chlorophenylalanine (p-CPA), has minimal impact on H2S-induced Cr tolerance. In conclusion, our findings suggest that H2S serves as a downstream signaling molecule involved in melatonin-induced Cr tolerance in maize. [ABSTRACT FROM AUTHOR]

Increasing concern over the safety of consumable products, particularly aquatic products, due to freshness issues, has become a pressing issue. Therefore, ensuring the quality and safety of aquatic products is paramount. To address this, a dual-mode colorimetric–fluorescence sensor utilizing Ce-MOF as a mimic peroxidase to detect H2S was developed. Ce-MOF was prepared by a conventional solvothermal synthesis method. Ce-MOF catalyzed the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to produce blue oxidized TMB (oxTMB). When dissolved, hydrogen sulfide (H2S) was present in the solution, and it inhibited the catalytic effect of Ce-MOF and caused the color of the solution to fade from blue to colorless. This change provided an intuitive indication for the detection of H2S. Through steady-state dynamic analysis, the working mechanism of this sensor was elucidated. The sensor exhibited pronounced color changes from blue to colorless, accompanied by a shift in fluorescence from none to light blue. Additionally, UV–vis absorption demonstrated a linear correlation with the H2S concentration, ranging from 200 to 2300 µM, with high sensitivity (limit of detection, LOD = 0.262 μM). Fluorescence intensity also showed a linear correlation, ranging from 16 to 320 µM, with high selectivity and sensitivity (LOD = 0.156 μM). These results underscore the sensor's effectiveness in detecting H2S. Furthermore, the sensor enhanced the accuracy of H2S detection and fulfilled the requirements for assessing food freshness and safety. [ABSTRACT FROM AUTHOR]

This article aims to investigate the atmospheric corrosion of carbon steel in a marine environment abundant in hydrogen sulfide (H2S) resulting from the decomposition of Sargassum seaweed. To accomplish this, four sites with varying degrees of impact were chosen along the coast of Martinique. The corrosion rates of steel were evaluated through mass loss measurements. After one year of exposure, the corrosion rates were notably high, particularly in atmospheres rich in Cl− ions and H2S, ranging from 107 µm to 983 µm. Complementing these findings, surface and product morphologies were characterized using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). These analyses revealed a significant degradation of the corrosion surface in the most affected atmospheres compared to those unaffected by Sargassum seaweed strandings. Lepidocrocite (γFeOOH) was identified as the predominant product regardless of the exposure atmosphere. However, goethite (αFeOOH) was found to be present in atmospheres most impacted by H2S. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S), previously regarded as a toxic exhaust and atmospheric pollutant, has emerged as the third gaseous signaling molecule following nitric oxide (NO) and carbon monoxide (CO). Recent research has revealed significant biological effects of H2S in a variety of systems, such as the nervous, cardiovascular, and digestive systems. Additionally, H2S has been found to impact reproductive system function and may have therapeutic implications for reproductive disorders. This paper explores the relationship between H2S and male reproductive disorders, specifically erectile dysfunction, prostate cancer, male infertility, and testicular damage. Additionally, it examines the impact of H2S regulation on the pathophysiology of the female reproductive system, including improvements in preterm birth, endometriosis, pre-eclampsia, fetal growth restriction, unexplained recurrent spontaneous abortion, placental oxidative damage, embryo implantation, recovery of myometrium post-delivery, and ovulation. The study delves into the regulatory functions of H2S within the reproductive systems of both genders, including its impact on the NO/cGMP pathway, the activation of K+ channels, and the relaxation mechanism of the spongy smooth muscle through the ROCK pathway, aiming to broaden the scope of potential therapeutic strategies for treating reproductive system disorders in clinical settings. [ABSTRACT FROM AUTHOR]

Cysteine and its derivatives, including H2S, can influence bacterial virulence and sensitivity to antibiotics. In minimal sulfate media, H2S is generated under stress to prevent excess cysteine and, together with incorporation into glutathione and export into the medium, is a mechanism of cysteine homeostasis. Here, we studied the features of cysteine homeostasis in LB medium, where the main source of sulfur is cystine, whose import can create excess cysteine inside cells. We used mutants in the mechanisms of cysteine homeostasis and a set of microbiological and biochemical methods, including the real-time monitoring of sulfide and oxygen, the determination of cysteine and glutathione (GSH), and the expression of the Fur, OxyR, and SOS regulons genes. During normal growth, the parental strain generated H2S when switching respiration to another substrate. The mutations affected the onset time, the intensity and duration of H2S production, cysteine and glutathione levels, bacterial growth and respiration rates, and the induction of defense systems. Exposure to chloramphenicol and high doses of ciprofloxacin increased cysteine content and GSH synthesis. A high inverse relationship between log CFU/mL and bacterial growth rate before ciprofloxacin addition was revealed. The study points to the important role of maintaining cysteine homeostasis during normal growth and antibiotic exposure in LB medium. [ABSTRACT FROM AUTHOR]

Leaf senescence is the terminal stage of leaf development, and its initiation and progression are closely controlled by the integration of a myriad of endogenous signals and environmental stimuli. It has been documented that WRKY transcription factors (TFs) play essential roles in regulating leaf senescence, yet the molecular mechanism of WRKY-mediated leaf senescence still lacks detailed elucidation in crop plants. In this study, we cloned and identified a tobacco WRKY TF gene, designated NtWRKY70b, acting as a positive regulator of natural leaf senescence. The expression profile analysis showed that NtWRKY70b transcript levels were induced by aging and hydrogen peroxide (H2O2) and downregulated upon hydrogen sulfide (H2S) treatment. The physiological and biochemical assays revealed that overexpression of NtWRKY70b (OE) clearly promoted leaf senescence, triggering increased levels of reactive oxygen species (ROS) and decreased H2S content, while disruption of NtWRKY70b by chimeric repressor silencing technology (SRDX) significantly delayed the onset of leaf senescence, leading to a decreased accumulation of ROS and elevated concentration of H2S. The quantitative real-time PCR analysis showed that the expression levels of various senescence-associated genes and ROS biosynthesis-related genes (NtRbohD and NtRbohE) were upregulated in OE lines, while the expression of H2S biosynthesis-related genes (NtDCD and NtCYSC1) were inhibited in OE lines. Furthermore, the Yeast one-hybrid analysis (Y1H) and dual luciferase assays showed that NtWRKY70b could directly upregulate the expression of an ROS biosynthesis-related gene (NtRbohD) and a chlorophyll degradation-related gene (NtPPH) by binding to their promoter sequences. Accordingly, these results indicated that NtWYKY70b directly activated the transcript levels of NtRbohD and NtPPH and repressed the expression of NtDCD and NtCYCS1, thereby promoting ROS accumulation and impairing the endogenous H2S production, and subsequently accelerating leaf aging. These observations improve our knowledge of the regulatory mechanisms of WRKY TFs controlling leaf senescence and provide a novel method for ensuring high agricultural crop productivity via genetic manipulation of leaf senescence in crops. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) has been recently recognized as an important gasotransmitter with cardioprotections, and iron is vital for various cellular activities. This study explored the regulatory role of H2S on iron metabolism and mitochondrial functions in cultured rat cardiac cells. Rotenone, a mitochondrial complex I inhibitor, was used for establishing an in vitro model of ischemic cell damage. It was first found that rotenone induced oxidative stress and lipid peroxidation and decreased mitochondrial membrane potential and ATP generation, eventually causing cell death. The supplement of H2S at a physiologically relevant concentration protected from rotenone-induced ferroptotic cell death by reducing oxidative stress and mitochondrial damage, maintaining GPx4 expression and intracellular iron level. Deferiprone, an iron chelator, would also protect from rotenone-induced ferroptosis. Further studies demonstrated that H2S inhibited ABCB8-mediated iron efflux from mitochondria to cytosol and promoted NFS1-mediated Fe-S cluster biogenesis. It is also found that rotenone stimulated iron-dependent H2S generation. These results indicate that H2S would protect cardiac cells from ischemic damage through preserving mitochondrial functions and intracellular Fe-S cluster homeostasis. [ABSTRACT FROM AUTHOR]

The organic sulfur-containing compounds glucosinolates (GSLs) and the novel gasotransmitter H2S are known to have cardioprotective effects. This study investigated the antioxidant effects and H2S-releasing potential of three GSLs ((3E)-4-(methylsulfanyl)but-3-enyl GSL or glucoraphasatin, 4-hydroxybenzyl GSL or glucosinalbin, and (RS)-6-(methylsulfinyl)hexyl GSL or glucohesperin) in rat cardiac cells. It was found that all three GSLs had no effect on cardiac cell viability but were able to protect against H2O2-induced oxidative stress and cell death. NaHS, a H2S donor, also protected the cells from H2O2-stimulated oxidative stress and cell death. The GSLs alone or mixed with cysteine, N-acetylcysteine, glutathione, H2O2, iron and pyridoxal-5′-phosphate, or mouse liver lysates did not induce H2S release. The addition of GSLs also did not alter endogenous H2S levels in cardiac cells. H2O2 significantly induced cysteine oxidation in the cystathionine gamma-lyase (CSE) protein and inhibited the H2S production rate. In conclusion, this study found that the three tested GSLs protect cardiomyocytes from oxidative stress and cell death but independently of H2S signaling. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) belongs to the family of gasotransmitters and can modulate a myriad of biological signaling pathways. Among others, its cardioprotective effects, through antioxidant, anti-inflammatory, anti-fibrotic, and proangiogenic activities, are well-documented in experimental studies. Cardiorespiratory failure, predominantly cardiomyopathy, is a life-threatening complication that is the number one cause of death in patients with Duchenne muscular dystrophy (DMD). Although recent data suggest the role of H2S in ameliorating muscle wasting in murine and Caenorhabditis elegans models of DMD, possible cardioprotective effects have not yet been addressed. In this review, we summarize the current understanding of the role of H2S in animal models of cardiac dysfunctions and cardiac cells. We highlight that DMD may be amenable to H2S supplementation, and we suggest H2S as a possible factor regulating DMD-associated cardiomyopathy. [ABSTRACT FROM AUTHOR]

H2S, a gasotransmitter that can be produced both via the transsulfuration pathway and non-enzymatically, plays a key role in vasodilation and angiogenesis during pregnancy. In fact, the involvement of H2S production on plasma levels of sFLT1, PGF, and other molecules related to preeclampsia has been demonstrated. Interestingly, we have found that maternal fructose intake (a common component of the Western diet) affects tissular H2S production. However, its consumption is allowed during pregnancy. Thus, (1) to study whether maternal fructose intake affects placental production of H2S in the offspring, when pregnant; and (2) to study if fructose consumption during pregnancy can increase the risk of preeclampsia, pregnant rats from fructose-fed mothers (10% w/v) subjected (FF) or not (FC) to a fructose supplementation were studied and compared to pregnant control rats (CC). Placental gene expression, H2S production, plasma sFLT1, and PGF were determined. Descendants of fructose-fed mothers (FC) presented an increase in H2S production. However, if they consumed fructose during their own gestation (FF), this effect was reversed so that the increase disappeared. Curiously, placental synthesis of H2S was mainly non-enzymatic. Related to this, placental expression of Cys dioxygenase, an enzyme involved in Cys catabolism (a molecule required for non-enzymatic H2S synthesis), was significantly decreased in FC rats. Related to preeclampsia, gene expression of sFLT1 (a molecule with antiangiogenic properties) was augmented in both FF and FC dams, although these differences were not reflected in their plasma levels. Furthermore, placental expression of PGF (a molecule with angiogenic properties) was decreased in both FC and FF dams, becoming significantly diminished in plasma of FC versus control dams. Both fructose consumption and maternal fructose intake induce changes in molecules that contribute to increasing the risk of preeclampsia, and these effects are not always mediated by changes in H2S production. [ABSTRACT FROM AUTHOR]

A discharge-flow reactor combined with modulated molecular beam mass spectrometry technique was employed to determine the rate constants of H-atom reactions with hydrogen sulfide and thiirane. The rate constants for both reactions were determined at a total pressure of 2 Torr from 220 to 950 K under pseudo-first-order conditions by monitoring either consumption of H atoms in excess of H2S (C4H4S) or the molecular species in excess of atomic hydrogen. For H + H2S reaction, a suggested previously strong curvature of the Arrhenius plot was confirmed: kl = 8.7 × 10−13 × (T/298)2.87 × exp(−125/T) cm3 molecule−1 s−1 with a conservative uncertainty of 15% at all temperatures. Non-Arrhenius behavior was also observed for the reaction of H-atom with C2H4S, with the experimental rate constant data being best fitted to a sum of two exponential functions: k2 = 1.85 × 10−10 exp(−1410/T) + 4.17 × 10−12 exp(−242/T) cm3 molecule−1 s−1 with an independent of temperature uncertainty of 15%. [ABSTRACT FROM AUTHOR]

A hybrid desulfurization process combining a physical filtration stage on cellular concrete (CC abiotic filter, called CCAF) and a biotrickling filter (called BTF) filled with expanded schist as packing material was used to remove high H2S concentrations from a synthetic gas containing dinitrogen (N2), dioxygen (O2) and H2S without the addition of a nutritive solution. Provided that small amounts of oxygen are present in the gas (1.2 ± 0.1% in volume), the global removal efficiency was 100%, and the global removal capacity reached 35 ± 2 gH2S m−3 h−1 for a total empty bed residence time (EBRT) of 120 s (CCAF + BTF). The resilience of the desulfurization process was demonstrated by applying severe changes in the H2S concentrations, from 160 to 1150 ± 20 mg m−3 for an EBRT = 120 s. According to the performances of the abiotic filter, which can decline over time due to the lifetime of the cellular concrete (137 days), the biotrickling filter reacted either as a refining system or as an efficient system able to treat significant H2S loading rates (up to 45 ± 3 gH2S m−3 h−1). Depending on the operating conditions, the increase in the pressure drops of the biotrickling filter (from 45 ± 3 to 234 ± 8 Pa m−1) highlighted biomass accumulation, especially extremophilic Acidithiobacillus sp. Considering the cellular concrete abiotic filter alone, removal capacities of up to 56 ± 3 gH2S m−3 h−1 were recorded for an EBRT of 60 s, demonstrating that gases such as landfill biogas or household biogas could be efficiently treated using this simple technique. [ABSTRACT FROM AUTHOR]

Modulation of mitochondrial K channels represents a pharmacological strategy to promote cardioprotective effects. Isothiocyanates emerge as molecules capable of releasing hydrogen sulfide (H2S), an endogenous pleiotropic gasotransmitter responsible for anti-ischemic cardioprotective effects also through the involvement of mitoK channels. Erucin (ERU) is a natural isothiocyanate resulting from the enzymatic hydrolysis of glucosinolates (GSLs) present in Eruca sativa Mill. seeds, an edible plant of the Brassicaceae family. In this experimental work, the specific involvement of mitoKATP channels in the cardioprotective effect induced by ERU was evaluated in detail. An in vivo preclinical model of acute myocardial infarction was reproduced in rats to evaluate the cardioprotective effect of ERU. Diazoxide was used as a reference compound for the modulation of potassium fluxes and 5-hydroxydecanoic acid (5HD) as a selective blocker of KATP channels. Specific investigations on isolated cardiac mitochondria were carried out to evaluate the involvement of mitoKATP channels. The results obtained showed ERU cardioprotective effects against ischemia/reperfusion (I/R) damage through the involvement of mitoKATP channels and the consequent depolarizing effect, which in turn reduced calcium entry and preserved mitochondrial integrity. [ABSTRACT FROM AUTHOR]

Biomass exploitation is a global trend due to the circular economy and the environmentally friendly spirit. Numerous applications are now based on the use of biomass-derived products. Hydrogen sulfide (H2S) is a highly toxic and environmentally hazardous gas which is emitted from various processes. Thus, the efficient removal of this toxic hazardous gas following cost-effective processes is an essential requirement. In this study, we present the synthesis and characterization of biomass-derived activated carbon/zinc oxide (ZnO@AC) composites from different biomass sources as potential candidates for H2S sorption. The synthesis involved a facile method for activated carbon production via pyrolysis and chemical activation of biomass precursors (spent coffee, Aloe-Vera waste leaves, and corncob). Activated carbon production was followed by the incorporation of zinc oxide nanoparticles into the porous carbon matrix using a simple melt impregnation method. The synthesized ZnO@AC composites were characterized using X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and nitrogen porosimetry. The H2S removal performance of the ZnO@AC composites was evaluated through sorption experiments using a handmade apparatus. Our findings demonstrate that the Aloe-Vera-, spent coffee-, and corncob-derived composites exhibit superior H2S sorption capacity up to 106 mgH2S/gads., 66 mgH2S/gads., and 47 mgH2S/gads., respectively. [ABSTRACT FROM AUTHOR]

Traditional treatment methods for tumors are inefficient and have severe side effects. At present, new therapeutic methods such as phototherapy, chemodynamic therapy, and gasodynamic therapy have been innovatively developed. High concentrations of hydrogen sulfide (H2S) gas exhibit cancer-suppressive effects. Herein, a Prussian blue-loaded tetra-sulfide modified dendritic mesoporous organosilica (PB@DMOS) was rationally constructed with glutathione (GSH)-triggered/photothermal-enhanced H2S signaling molecule release properties for gas therapy. The as-synthesized nanoplatform confined PB nanoparticles in the mesoporous structure of organosilica silica due to electrostatic adsorption. In the case of a GSH overexpressed tumor microenvironment, H2S gas was controllably released. And the temperature increases due to the photothermal effects of PB nanoparticles, further enhancing H2S release. At the same time, PB nanoparticles with excellent hydrogen peroxide catalytic performance also amplified the efficiency of tumor therapy. Thus, a collective nanoplatform with gas therapy/photothermal therapy/catalytic therapy functionalities shows potential promise in terms of efficient tumor therapy. [ABSTRACT FROM AUTHOR]

A two-dimensional (2D) van der Waals material composed only of tellurium (Te) atoms—tellurene—is drawing attention because of its high intrinsic electrical conductivity and strong interaction with gas molecules, which could allow the development of high-performance chemiresistive sensors. However, the correlation between the morphologies and gas detection properties of tellurene has not yet been studied in depth, and few reports exist on tellurene-based hydrogen sulfide (H2S) chemiresistive sensors in spite of their strong interaction with H2S molecules. Here, we investigate the morphology-dependent H2S gas detection properties of tellurene synthesized using a hydrothermal method. To tailor the morphologies of tellurene, the molecular weight of the surfactant was controlled, revealing that a 1D or 2D form was synthesized and also accompanied with the high crystallinity. The 1D tellurene-based chemiresistive sensor presented superior H2S detection properties compared to the 2D form, achieving a gas response (Rg/Ra) of ~38, even at room temperature. This outstanding performance was attributed to the high intrinsic electrical conductivity and high specific surface area of the resultant 1D tellurene. [ABSTRACT FROM AUTHOR]

Understanding the reduction of CO2 and the origin and evolution of early life on Earth is an important research endeavor. Pyrite, due to its semiconductor properties, is believed to play a pivotal role as a reactant or catalyst in converting reducing gases, such as CO2, into organic matter. In this study, we employed density functional theory (DFT) to investigate the reduction of CO2 in the presence of H2S on the surface of pyrite. Our findings reveal that the presence of sulfur vacancies enhances the adsorption of H2S and CO2 molecules onto the pyrite surface. Interestingly, we observed the generation of the HCOOH molecule on the defective pyrite surface. Additionally, the transition state analysis indicates that H2S and CO2 molecules require the overcoming of an energy barrier (Ea) of 36.93 kJ/mol to form the HCOOH molecule. This study sheds light on the role of pyrite in the early creation of life on Earth by elucidating its impact on the reduction of carbon dioxide. [ABSTRACT FROM AUTHOR]

Blue holes are submarine karst cavities with chemical and physical characteristics of the water column completely different from those in the surrounding environment. In this study a multi-parameter probe was used, for the first time, to characterise the water column of the Blue Hole of Faanu Madugau (Ari Atoll, Maldives, 3°55.799′ E 72°56.469′ N), the only blue hole described in the Indian Ocean up to date. Measurements of the temperature, salinity, dissolved oxygen, turbidity, chlorophyll-α, photosynthetically active radiation, potential density, pH, and H2S were obtained with a high detail. Three distinct physical–chemical layers were identified from the surface up to 70 m depth. An intermediate and turbid layer, located between 40 m and 46 m depth, sharply separates the upper layer displaying water characteristics equal to those of the outside environment from the deep and more characteristic layer of the blue hole, where a unique environment can be observed. Waters are oxygenated, warm, and rich in chlorophyll-α in the upper layer, whilst waters are anoxic, colder, denser, and completely dark, with low pH values and high H2S content in the deep layer. The Blue Hole of the Maldives represents an extreme environment from a geological, oceanographic, biological, and ecological point of view. Further investigations will be thus required to understand the origin of the Blue Hole waters, the mechanisms that keep it isolated from the external environment, the influence of weather and marine forcing on it, and how climate change may impact it. [ABSTRACT FROM AUTHOR]

Vacuolar H+-translocating ATPase (V-ATPase) is a proton pump crucial for plant growth and survival. For this reason, its activity is tightly regulated, and various factors, such as signaling molecules and phytohormones, may be involved in this process. The aim of this study was to explain the role of jasmonic acid (JA) in the signaling pathways responsible for the regulation of V-ATPase in cucumber roots and its relationship with other regulators of this pump, i.e., H2S and H2O2. We analyzed several aspects of the JA action on the enzyme, including transcriptional regulation, modulation of protein levels, and persulfidation of selected V-ATPase subunits as an oxidative posttranslational modification induced by H2S. Our results indicated that JA functions as a repressor of V-ATPase, and its action is related to a decrease in the protein amount of the A and B subunits, the induction of oxidative stress, and the downregulation of the E subunit persulfidation. We suggest that both H2S and H2O2 may be downstream components of JA-dependent negative proton pump regulation. The comparison of signaling pathways induced by two negative regulators of the pump, JA and cadmium, revealed that multiple pathways are involved in the V-ATPase downregulation in cucumber roots. [ABSTRACT FROM AUTHOR]

In order to cope with increased demands for energy and metabolites as well as to enhance stress resilience, tumor cells develop various metabolic adaptations, representing a hallmark of cancer. In this regard, the dysregulation of sulfur metabolism that may result in elevated levels of volatile sulfur compounds (VSCs) in body fluids, breath, and/or excretions of cancer patients has recently gained attention. Besides hydrogen sulfide (H2S), methanethiol is the predominant cancer-associated VSC and has been proposed as a promising biomarker for non-invasive cancer diagnosis. Gut bacteria are the major exogenous source of exposure to this foul-smelling toxic gas, with methanethiol-producing strains such as Fusobacterium nucleatum highly abundant in the gut microbiome of colorectal carcinoma (CRC) patients. Physiologically, methanethiol becomes rapidly degraded through the methanethiol oxidase (MTO) activity of selenium-binding protein 1 (SELENBP1). However, SELENBP1, which is considered a tumor suppressor, is often downregulated in tumor tissues, and this has been epidemiologically linked to poor clinical outcomes. In addition to impaired removal, an increase in methanethiol levels may derive from non-enzymatic reactions, such as a Maillard reaction between glucose and methionine, two metabolites enriched in cancer cells. High methionine concentrations in cancer cells may also result in enzymatic methanethiol production in mitochondria. Moreover, enzymatic endogenous methanethiol production may occur through methyltransferase-like protein 7B (METTL7B), which is present at elevated levels in some cancers, including CRC and hepatocellular carcinoma (HCC). In conclusion, methanethiol contributes to the scent of cancer as part of the cancer-associated signature combination of volatile organic compounds (VOCs) that are increasingly being exploited for non-invasive early cancer diagnosis. [ABSTRACT FROM AUTHOR]

The saphenous vein is the conduit of choice for bypass grafting. Unfortunately, the hemodynamic stress associated with the arterial environment of the bypass vein graft leads to the development of intimal hyperplasia (IH), an excessive cellular growth and collagen deposition that results in restenosis and secondary graft occlusion. Hydrogen sulfide (H2S) is a ubiquitous redox-modifying gasotransmitter that inhibits IH. H2S is produced via the reverse trans-sulfuration pathway by three enzymes: cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). However, the expression and regulation of these enzymes in the human vasculature remains unclear. Here, we investigated the expression of CSE, CBS and 3-MST in segments of native human saphenous vein and large arteries. Furthermore, we evaluated the regulation of these enzymes in vein segments cultured under static, venous (7 mmHg pressure) or arterial (100 mmHg pressure) pressure. CSE was expressed in the media, neointima and intima of the vessels and was negatively regulated by arterial shear stress. Adenoviral-mediated CSE overexpression or RNA interference-mediated CSE knock-down revealed that CSE inhibited primary human VSMC migration but not proliferation. We propose that high shear stress in arteriovenous bypass grafts inhibits CSE expression in both the media and endothelium, which may contribute to increased VSMC migration in the context of IH. [ABSTRACT FROM AUTHOR]

Chemiresistive gas sensors were produced by functionalizing graphene with a ~3 nm layer of mixed oxide xCu2O⸱yMnO using pulsed laser deposition (PLD) from a hopcalite CuMn2O4 target. Sensor response time traces were recorded for strongly oxidizing (NO2, O3) and reducing (NH3, H2S) poisonous gases at ppb and ppm levels, respectively. The morphology of the MOX layer was modified by growth temperature during PLD, resulting in the optimization of the sensor response. Differences in decomposition or oxidation rates on catalytically active metal oxide (MOX) were utilized to achieve partial selectivity for pairs of gases that have similar adsorption and redox properties. The predominant selectivity towards ozone in most samples at different measuring conditions remained difficult to suppress. A distinct selectivity for H2S emerged at higher measurement temperatures (100–150 °C), which was assigned to catalytic oxidation with O2. Several gas–MOX interaction mechanisms were advanced to tentatively explain the sensor behavior, including reversible electron transfer in the simplest case of NO2, decomposition via ionic transients for O3, and complex catalytic oxidative transformations for NH3 and H2S. [ABSTRACT FROM AUTHOR]

Peripheral artery disease (PAD) affects more than 230 million people worldwide. PAD patients suffer from reduced quality of life and are at increased risk of vascular complications and all-cause mortality. Despite its prevalence, impact on quality of life and poor long-term clinical outcomes, PAD remains underdiagnosed and undertreated compared to myocardial infarction and stroke. PAD is due to a combination of macrovascular atherosclerosis and calcification, combined with microvascular rarefaction, leading to chronic peripheral ischemia. Novel therapies are needed to address the increasing incidence of PAD and its difficult long-term pharmacological and surgical management. The cysteine-derived gasotransmitter hydrogen sulfide (H2S) has interesting vasorelaxant, cytoprotective, antioxidant and anti-inflammatory properties. In this review, we describe the current understanding of PAD pathophysiology and the remarkable benefits of H2S against atherosclerosis, inflammation, vascular calcification, and other vasculo-protective effects. [ABSTRACT FROM AUTHOR]

The ability of hydrogen sulfide (H2S) to protect bacteria from bactericidal antibiotics has previously been described. The main source of H2S is the desulfurization of cysteine, which is either synthesized by cells from sulfate or transported from the medium, depending on its composition. Applying electrochemical sensors and a complex of biochemical and microbiological methods, changes in growth, respiration, membrane potential, SOS response, H2S production and bacterial survival under the action of bactericidal ciprofloxacin and bacteriostatic chloramphenicol in commonly used media were studied. Chloramphenicol caused a sharp inhibition of metabolism in all studied media. The physiological response of bacteria to ciprofloxacin strongly depended on its dose. In rich LB medium, cells retained metabolic activity at higher concentrations of ciprofloxacin than in minimal M9 medium. This decreased number of surviving cells (CFU) by 2–3 orders of magnitude in LB compared to M9 medium, and shifted optimal bactericidal concentration (OBC) from 0.3 µg/mL in M9 to 3 µg/mL in LB. Both drugs induced transient production of H2S in M9 medium. In media containing cystine, H2S was produced independently of antibiotics. Thus, medium composition significantly modifies physiological response of E. coli to bactericidal antibiotic, which should be taken into account when interpreting data and developing drugs. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) is a colourless, odourless, and toxic gas. Long-term exposure to high concentrations of CO causes poisoning and even death; therefore, CO removal is particularly important. Current research has focused on the efficient and rapid removal of CO via low-temperature (ambient) catalytic oxidation. Gold nanoparticles are widely used catalysts for the high-efficiency removal of high concentrations of CO at ambient temperature. However, easy poisoning and inactivation due to the presence of SO2 and H2S affect its activity and practical application. In this study, a bimetallic catalyst, Pd-Au/FeOx/Al2O3, with a Au:Pd ratio of 2:1 (wt%) was formed by adding Pd nanoparticles to a highly active Au/FeOx/Al2O3 catalyst. Its analysis and characterisation proved that it has improved catalytic activity for CO oxidation and excellent stability. A total conversion of 2500 ppm of CO at −30 °C was achieved. Furthermore, at ambient temperature and a volume space velocity of 13,000 h−1, 20,000 ppm CO was fully converted and maintained for 132 min. Density functional theory (DFT) calculations and in situ FTIR analysis revealed that Pd-Au/FeOx/Al2O3 exhibited stronger resistance to SO2 and H2S adsorption than the Au/FeOx/Al2O3 catalyst. This study provides a reference for the practical application of a CO catalyst with high performance and high environmental stability. [ABSTRACT FROM AUTHOR]

In this work, we present an analysis of the antibacterial activity of TiS3 nanostructures in water and 0.9% NaCl solution suspensions. TiS3 nanoribbons 1–10 µm long, 100–300 nm wide, and less than 100 nm thick were produced by the direct reaction of pure titanium powder with elemental sulphur in a quartz tube sealed under vacuum. For the toxicity test of a bioluminescent strain of E. coli we used concentrations from 1 to 0.0001 g L−1 and also studied fresh suspensions and suspensions left for 24 h. The strongest toxic effect was observed in freshly prepared water solutions where the luminescence of bacteria decreased by more than 75%. When saline solution was substituted for water or when the solutions were stored for 24 h it resulted in a considerable decrease in the TiS3 antibacterial effect. The toxicity of TiS3 in water exceeded the toxicity of the reference TiO2 nanoparticles, though when saline solution was used instead of water the opposite results were observed. In addition, we did not find a relationship between the antibacterial activity of water suspensions of nanoribbons and the stability of their colloidal systems, which indicates an insignificant contribution to the toxicity of aggregation processes. In 0.9% NaCl solution suspensions, toxicity increased in proportion to the increase in the zeta potential. We suppose that the noted specificity of toxicity is associated with the emission of hydrogen sulphide molecules from the surface of nanoribbons, which, depending on the concentration, can either decrease or increase oxidative stress, which is considered the key mechanism of nanomaterial cytotoxicity. However, the exact underlying mechanisms need further investigation. Thus, we have shown an important role of the dispersion medium and the period of storage in the antibacterial activity of TiS3 nanoribbons. Our results could be used in nanotoxicological studies of other two-dimensional nanomaterials, and for the development of novel antibacterial substances and other biomedical applications of this two-dimensional material. [ABSTRACT FROM AUTHOR]

The atmospheric corrosion of copper exposed in Martinique (Caribbean Sea) for 1 year was reported. This island suffered the stranding of sargassum algae, which decompose and release toxic gases such as hydrogen sulfide (H2S) or ammonia (NH3). Four sites in Martinique (France) more or less impacted by sargassum algae strandings were selected. The corrosion rate was studied via mass loss determination. The morphology and properties of the corrosion products were determined using Scanning Electron Microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The samples were exposed for up to 12 months. The mass loss results after 1-year exposure were from 4.8 µm for the least impacted site to 325 µm for the site most affected by sargassum algae. This very high value proves that the presence of sargassum algae caused a significant degradation of copper. The morphological structures and properties of the corrosion products obtained at the impacted and non-impacted sites differed significantly. In the absence of sargassum algae, classical corrosion products of copper were reported such as Cu2O and Cu2Cl(OH)3. In the sites near the stranding of the sargassum algae, the CuS product is the main corrosion product obtained, but copper hydroxylsulfate is created. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) detection is extremely necessary due to its hazardous nature. Thus, the design of novel sensors to detect H2S gas at low temperatures is highly desirable. In this study, a series of nanocomposites based on MoS2 octahedrons and ZnO-Zn2SnO4 nanoparticles were synthesized through the hydrothermal method. Various characterizations such as X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectrum (XPS) have been used to verify the crystal phase, morphology and composition of synthesized nanocomposites. Three gas sensors based on the nanocomposites of pure ZnO-Zn2SnO4 (MS-ZNO-0), 5 wt% MoS2-ZnO-Zn2SnO4 (MS-ZNO-5) and 10 wt% MoS2-ZnO-Zn2SnO4 (MS-ZNO-10) were fabricated to check the gas sensing properties of various volatile organic compounds (VOCs). It showed that the gas sensor of (MS-ZNO-5) displayed the highest response of 4 to 2 ppm H2S and fewer responses to all other tested gases at 30 °C. The sensor of MS-ZNO-5 also displayed humble selectivity (1.6), good stability (35 days), promising reproducibility (5 cycles), rapid response/recovery times (10 s/6 s), a limit of detection (LOD) of 0.05 ppm H2S (Ra/Rg = 1.8) and an almost linear relationship between H2S concentration and response. Several elements such as the structure of MoS2, higher BET-specific surface area, n-n junction and improvement in oxygen species corresponded to improving response. [ABSTRACT FROM AUTHOR]

Effects of hydrogen sulfide (H2S) on the browning and quality maintenance of fresh-cut peach fruit were studied. The results showed that H2S treatment repressed the development of surface browning, suppressed the increase in respiration rate and weight loss, and delayed the decline of firmness while soluble solids content (SSC) and microbial growth were unaffected during storage. H2S treatment maintained higher contents of phenolic compounds, especially neo-chlorogenic acid, catechin, and quercetin, and delayed the degradation of phenolic compounds by enhancing the activities of phenolic biosynthesis-related enzymes and inhibiting the oxidative activities of polyphenol oxidase (PPO) in comparison with control. Moreover, H2S stimulated the accumulation of amino acids and their derivatives including proline, γ-aminobutyric acid (GABA), and polyamines (PAs) via enhancing biosynthesis and repressing degradation compared to control. These results suggested that H2S treatment enhanced the accumulation of phenolic, amino acids, and their derivatives by modulating phenolic and amino acids metabolisms, which contributed to the higher antioxidant activity and membrane integrity maintenance, ultimately repressing browning development and maintaining the quality. Therefore, the current study speculated that H2S might be a promising approach for browning inhibition and quality maintenance in fresh-cut peach fruit. [ABSTRACT FROM AUTHOR]

Kidney extraction time has a detrimental effect on post-transplantation outcome. This study aims to improve the flush-out and potentially decrease ischemic injury by the addition of hydrogen sulphide (H2S) to the flush medium. Porcine kidneys (n = 22) were extracted during organ recovery surgery. Pigs underwent brain death induction or a Sham operation, resulting in four groups: donation after brain death (DBD) control, DBD H2S, non-DBD control, and non-DBD H2S. Directly after the abdominal flush, kidneys were extracted and flushed with or without H2S and stored for 13 h via static cold storage (SCS) +/− H2S before reperfusion on normothermic machine perfusion. Pro-inflammatory cytokines IL-1b and IL-8 were significantly lower in H2S treated DBD kidneys during NMP (p = 0.03). The non-DBD kidneys show superiority in renal function (creatinine clearance and FENa) compared to the DBD control group (p = 0.03 and p = 0.004). No differences were seen in perfusion parameters, injury markers and histological appearance. We found an overall trend of better renal function in the non-DBD kidneys compared to the DBD kidneys. The addition of H2S during the flush out and SCS resulted in a reduction in pro-inflammatory cytokines without affecting renal function or injury markers. [ABSTRACT FROM AUTHOR]

The presented work is devoted to the preparation of nanocomposites based on multiwall carbon nanotubes (MWCNTs) and copper (Cu) nanoparticles by a simple chemical method, and to study their sensing properties to hydrogen sulfide (H2S) gas. The Cu decorated multiwall carbon nanotubes (MWCNTs/Cu) were prepared by the deposition of very thin Cu layers on the pristine and functionalized multiwall carbon nanotubes (f-MWCNTs) using both physical (electron beam evaporation (EBE)) and chemical (electrochemical deposition) methods. MWCNTs/Cu prepared in the two above-mentioned ways, their sensing properties were studied, and the results were comparatively analyzed. The effect of the chemical functionalization of MWCNTs by oxygen-containing groups on the sensing properties of these f-MWCNT/Cu nanocomposites has been investigated. All the prepared sensors demonstrated high sensitivity and selectivity to H2S in the air at room temperature. The f-MWCNT/Cu structure obtained by the chemical method demonstrated about 5 times (~400%) higher sensitivity (∆R/R0) to H2S gas compared to the similar structure obtained by the physical method. The temperature effect on sensory characteristics (response and self-recovery time) of the f-MWCNTs/Cu structure was also studied. [ABSTRACT FROM AUTHOR]

High temperature corrosion poses a great threat to boiler water wall safe operation. To investigate the corrosion root cause, a 300 MW level boiler water wall high temperature H2S corrosion case was reported. The typical hydrogen sulfide H2S corrosion feature was large amounts of sulfur which could be found in the cut down sample tube corrosion layer, with a thickness of 482 μm. In addition, huge amounts of lead (Pb) could be found in the corrosion layer, which resulted from the lead sulfide (PbS) deposition when the high temperature flue gas condensed at the water wall tubes. Meanwhile, the sulfur in the corrosion layer was closely related to the H2S concentration in the water wall ambience. The related ambience test showed that the H2S could achieve up to 1000 ppm when the boiler was in operation, far larger than the suggested reference value of 100 ppm. Hence, the overlarge H2S concentration was a vital factor for the tube corrosion. To further investigate the reason why the H2S was kept in such high concentration in the boiler long term operation, and the reasons for the over-high sulfur content in the coal and the over-large diameter of the imaginary circle of primary air (DICPA), two factors were obtained. The peak sulfur content reached 2.5% and the suggested sulfur content was below 1%. The DICPA was so large (1580 mm) that the pulverized coal easily scoured the water wall tubes, which would boost the thinning process of the tubes. To relieve the high temperature corrosion, improve the coal qualities, decrease the DICPA, adjust the operation diameter and adopt a coating technology four measures were suggested. [ABSTRACT FROM AUTHOR]

Simple Summary: Lupus nephritis is a severe and fatal immune-associated nephritis. The molecular mechanisms underlying lupus nephritis development remain largely unknown. Renal hydrogen sulfide can be produced mainly via two synthetases and is involved in many pathological and physiological processes. Herein, we sought to investigate the roles of renal hydrogen sulfide and its synthetase in lupus nephritis pathogenesis. We found that the expression of two hydrogen sulfide synthetases was downregulated in renal tissues of lupus nephritis patients and lupus mice, which were associated with poor renal outcomes. Moreover, exogenous hydrogen sulfide attenuated renal damage in two mouse models with lupus nephritis. In addition, we further confirmed the increase of renal key transcription factors and T-lymphocyte infiltration in lupus nephritis, which were mitigated after treatment with hydrogen sulfide donors. Our composite data indicated that reduced renal two hydrogen sulfide synthetases contribute to the progress of lupus nephritis, and exogenous hydrogen-sulfide-attenuated renal damage of lupus nephritis may partly be through inhibiting the expression of T-lymphocyte-associated transcription factors. The molecular mechanisms underlying lupus nephritis (LN) pathogenesis are not fully understood. Hydrogen sulfide (H2S) is involved in many pathological and physiological processes. We sought to investigate the roles of H2S in LN pathogenesis. H2S synthase cystathionine–lyase (CSE) and cystathionine–synthetase (CBS) expression was downregulated in renal tissues of patients with LN and their levels were associated with LN's prognosis using the Nephroseq database. Reduced CSE and CBS protein expression in kidney tissues of LN patients and MRL/lpr mice were confirmed by immunohistochemistry. CSE and CBS mRNA levels were reduced in MRL/lpr and pristine- and R848-induced lupus mice. Given that H2S exerts an anti-inflammatory role partly via regulating inflammatory transcription factors (TFs), we analyzed hub TFs by using a bioinformatics approach. It showed that STAT1, RELA, and T-cell-related signaling pathways were enriched in LN. Increased STAT1 and RELA expression were confirmed in renal tissues of LN patients. Treatment of MRL/lpr and pristine mice with H2S donors alleviated systemic lupus erythematosus (SLE) phenotypes and renal injury. H2S donors inhibited RELA level and T-cell infiltration in the kidneys of MRL/lpr and pristine mice. Our data indicated that CSE/CBS/H2S contributes to LN pathogenesis. Supplementation of H2S would be a potential therapeutic strategy for LN. [ABSTRACT FROM AUTHOR]

Because hydrogen sulfide (H2S) is classified as a gaseous signaling molecule, protein S-sulfhydration is known to be one of the mechanisms by which H2S signals are conducted. PTP1B, a negative regulator in insulin signaling, has been found to be S-sulfhydrated at Cys215-SH to form Cys215-SSH in response to endoplasmic reticulum (ER) stress. Therefore, we aimed to understand the change in PTP1B S-sulfhydration and cellular redox homeostasis in response to insulin stimulation. We demonstrated a feasible PEG-switch method to determine the levels of PTP1B S-sulfhydration. According to the results obtained from HEK293T and MDA-MB-231 cells, insulin induced a change in PTP1B S-sulfhydration that was similar to the change in Insulin receptor substrate 1 (IRS1) phosphorylation in both cell lines. However, insulin-induced PTP1B S-sulfhydration and IRS1 phosphorylation were only significantly affected by metformin in HEK293T cells. Insulin also induced an increase in reactive oxygen species (ROS) in both cell lines. However, the level of H2S, GSH, and GSSG was only significantly affected by insulin and metformin in HEK293T cells. HEK293T cells maintained high levels of H2S and cysteine, but low levels of GSSG and GSH in general compared to MDA-MB-231 cells. From these findings, we suggest that PTP1B activity is modulated by H2S and redox-regulated S-sulfhydration during insulin signaling. [ABSTRACT FROM AUTHOR]

Intestinal dysbiosis plays an important role in the pathogenesis of colitis (UC). Schizonepetae Herba can achieve anti-inflammatory effects as a medicine and food homologous vegetable. Luteolin, eriodictyol, fisetin, and kaempferol are the main anti-inflammatory active compounds obtained through mass spectrometry from the methanol extract of Schizonepetae Spica (JJSM). JJSM intervention resulted in attenuated weight loss, high disease-activity-index score, colon length shortening and colonic pathological damage in DSS-induced colitis mice. Interestingly, hydrogen sulfide (H2S) was inhibited remarkably, which is helpful to elucidate the relationship between active substance and intestinal flora. Furthermore, JJSM administration improved intestinal flora with down-regulating the abundance of harmful bacteria such as Clostridiales and Desulfovibrio and up-regulating the abundance of beneficial bacteria such as Muribaculaceae and Ligolactobacillus and enhanced the production of SCFAs. It is worth noticing that Desulfovibrio is related to the production of intestinal gas H2S. The elevated levels of Desulfovibrio and H2S will hasten the onset of colitis, which is a crucial risk factor for colitis. The results displayed that JJSM could considerably ameliorate colitis by rebuilding H2S-related intestinal flora, which provides a new therapeutic strategy for Schizonepetae Spica to be utilized as a functional food and considered as an emerging candidate for intestinal inflammation. [ABSTRACT FROM AUTHOR]

Endogenously produced hydrogen sulfide (H2S) is critical for cardiovascular homeostasis. Therapeutic strategies aimed at increasing H2S levels have proven cardioprotective in models of acute myocardial infarction (MI) and heart failure (HF). The present study was undertaken to investigate the effects of a novel H2S prodrug, SG-1002, on stress induced hypertrophic signaling in murine HL-1 cardiac muscle cells. Treatment of HL-1 cells with SG-1002 under serum starvation without or with H2O2 increased the levels of H2S, H2S producing enzyme, and cystathionine β-synthase (CBS), as well as antioxidant protein levels, such as super oxide dismutase1 (SOD1) and catalase, and additionally decreased oxidative stress. SG-1002 also decreased the expression of hypertrophic/HF protein markers such as atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), galectin-3, TIMP1, collagen type III, and TGF-β1 in stressed HL-1 cells. Treatment with SG-1002 caused a significant induction of cell viability and a marked reduction of cellular cytotoxicity in HL-1 cells under serum starvation incubated without or with H2O2. Experimental results of this study suggest that SG-1002 attenuates myocardial cellular oxidative damage and/or hypertrophic signaling via increasing H2S levels or H2S producing enzymes, CBS, and antioxidant proteins. [ABSTRACT FROM AUTHOR]

Obesity, along with type 2 diabetes mellitus (T2DM), is a major contributor to hypertension. The renin-angiotensin-aldosterone system is involved in the occurrence of diabetes and hypertension. However, the mechanism by which obesity is related to T2DM induced hypertension is unclear. In this study, we observed that blood pressure and serum renin content were increased in patients with diabetes and hypertension. Hydrogen sulfide (H2S), as an endogenous bioactive molecule, has been shown to be a vasodilator. Db/db mice, characterized by obesity and T2DM, and juxtaglomerular (JG) cells, which line the afferent arterioles at the entrance of the glomeruli to produce renin, treated with glucose, palmitic acid (PA) and oleic acid (OA), were used as animal and cellular models. NaHS, the H2S donor, was administered to db/db mice through intraperitoneal injection. NaHS significantly alleviated blood pressure in db/db mice, decreased the renin content in the serum of db/db mice and reduced renin secretion from JG cells. NaHS modulated renin release via cAMP and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), including synaptosome-associated protein 23 (SNAP23) and vesicle-associated membrane protein 2 (VAMP2), which mediate renin exocytosis. Furthermore, NaHS increased the levels of autophagy-related proteins and colocalization with EGFP-LC3 puncta with renin-containing granules and VAMP2 to consume excessive renin to maintain intracellular homeostasis. Therefore, exogenous H2S attenuates renin release and promotes renin-vesicular autophagy to relieve diabetes-induced hypertension. [ABSTRACT FROM AUTHOR]

The slight but cumulative influence of impurity gases in air poses a great threat to the long-term stability of room-temperature gas sensors. Room-temperature hydrogen-sensitive Pt–SnO2 composite nanoceramics of 5 wt% Pt were prepared through pressing and sintering. The response of a sample was over 10,000 after being exposed to 500 ppm H2S–20% O2–N2 at room temperature, and the room-temperature hydrogen sensing capacity was seriously degraded even for samples that had aged dozens of days since H2S exposure. Mild heat treatments such as 160 °C for 10 min were found able to fully activate those H2S-exposed samples. As the peak of S 2p electron was clearly detected in H2S-exposed samples, it was proposed that for room-temperature hydrogen-sensitive Pt–SnO2 composite nanoceramics, H2S exposure induced degradation results from the poisoning of Pt by H2S deposited on it, which can be removed through a mild heat treatment. Periodic mild heat treatment should be a convenient and effective measure for room-temperature metal oxide gas sensors to achieve long-term stability through preventing the accumulation of impurity gases in air deposited on them. [ABSTRACT FROM AUTHOR]

Reaction F + H2S→SH + HF (1) is an effective source of SH radicals and an important intermediate in atmospheric and combustion chemistry. We employed a discharge-flow, modulated molecular beam mass spectrometry technique to determine the rate coefficient of this reaction and that of the secondary one, F + SH→S + HF (2), at a total pressure of 2 Torr and in a wide temperature range 220–960 K. The rate coefficient of Reaction (1) was determined directly by monitoring consumption of F atoms under pseudo-first-order conditions in an excess of H2S. The rate coefficient of Reaction (2) was determined via monitoring the maximum concentration of the product of Reaction (1), SH radical, as a function of [H2S]. Both rate coefficients were found to be virtually independent of temperature in the entire temperature range of the study: k1 = (1.86 ± 0.28) × 10−10 and k2 = (2.0 ± 0.40) × 10−10 cm3 molecule−1 s−1. The kinetic data from the present study are compared with previous room temperature measurements. [ABSTRACT FROM AUTHOR]

Malus is an economically important plant that is widely cultivated worldwide, but it often encounters saline–alkali stress. The composition of saline–alkali land is a variety of salt and alkali mixed with the formation of alkaline salt. Hydrogen sulfide (H2S) has been reported to have positive effects on plant responses to abiotic stresses. Our previous study showed that H2S pretreatment alleviated the damage caused by alkaline salt stress to Malus hupehensis Rehd. var. pingyiensis Jiang (Pingyi Tiancha, PYTC) roots by regulating Na+/K+ homeostasis and oxidative stress. In this study, transcriptome analysis was used to investigate the overall mechanism through which H2S alleviates alkaline salt stress in PYTC roots. Simultaneously, differentially expressed genes (DEGs) were explored. Transcriptional profiling of the Control-H2S, Control-AS, Control-H2S + AS, and AS-H2S + AS comparison groups identified 1618, 18,652, 16,575, and 4314 DEGs, respectively. Further analysis revealed that H2S could alleviate alkaline salt stress by increasing the energy maintenance capacity and cell wall integrity of M. hupehensis roots and by enhancing the capacity for reactive oxygen species (ROS) metabolism because more upregulated genes involved in ROS metabolism and sulfur-containing compounds were identified in M. hupehensis roots after H2S pretreatment. qRT-PCR analysis of H2S-induced and alkaline salt-response genes showed that these genes were consistent with the RNA-seq analysis results, which indicated that H2S alleviation of alkaline salt stress involves the genes of the cell wall and sulfur-containing compounds in PYTC roots. [ABSTRACT FROM AUTHOR]

Urotensin II (UII) could increase blood pressure and heart rate via increased central reactive oxygen species (ROS) levels. We reported previously that hydrogen sulfide (H2S) exerts an antihypertensive effect by suppressing ROS production. The aim of the current study is to further examine the effects of endogenous and exogenous H2S on UII-induced cardiovascular effects by using an integrated physiology approach. We also use cell culture and molecular biological techniques to explore the inhibitory role of H2S on UII-induced cardiovascular effects. In this study, we found that cystathionine-β-synthase (CBS), the main H2S synthesizing enzyme in CNS, was expressed in neuronal cells of the rostral ventrolateral medulla (RVLM) area. Cellular distribution of CBS and urotensin II receptor (UT) in SH-SY5Y cells that are confirmed as glutamatergic were identified by immunofluorescent and Western blots assay. In Sprague–Dawley rats, administration of UII into the RVLM resulted in an increase in mean arterial pressure (MAP), heart rate (HR), ROS production, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and phosphorylation of p47phox, extracellular signal-regulated protein kinase (ERK)1/2 and p38MAPK, but not stress-activated protein kinase/Jun N-terminal kinase (SAPK/JNK). These effects of UII were attenuated by application into the RVLM of endogenous (L-cysteine, SAM) or exogenous (NaHS) H2S. These results were confirmed in SH-SY5Y cells. UII-induced cardiovascular effects were also significantly abolished by pretreatment with microinjection of Tempol, Apocynin, SB203580, or PD98059 into the RVLM. Preincubated SH-SY5Y cells with Apocynin before administration of UII followed by Western blots assay showed that ROS is in the upstream of p38MAPK/ERK1/2. Gao activation assay in SH-SY5Y cells suggested that H2S may exert an inhibitory role on UII-induced cardiovascular effects by inhibiting the activity of Gαo. These results suggest that both endogenous and exogenous H2S attenuate UII-induced cardiovascular effects via Gαo-ROS-p38MAPK/ERK1/2 pathway. [ABSTRACT FROM AUTHOR]

Cystathionine-γ-lyase (CSE) is expressed in various tissues and generates H2S via an alternative desulfuration reaction. We sought to explore the functions of skeletal muscle CSE using skeletal muscle conditional knockout CSE (MCSEKO) mice. It was found that body weight, muscle morphology, and exercise capacity were not altered in MCSEKO mice compared with littermate wild-type mice. RNA-seq-based transcriptome analysis showed that 275 genes were differentially regulated in skeletal muscle and multiple signaling pathways including insulin signaling and mTOR, PI3K-AKT, and cGMP-PKG signaling pathways were enriched in MCSEKO mice. The intraperitoneal glucose tolerance test and insulin tolerance test showed that glucose tolerance and insulin sensitivity were reduced in MCSEKO mice. Glucose transporter 4 (GLU4) and PKG-1 expression levels and insulin receptor substrate-1(IRS1)/PI3K/Akt signaling pathway were downregulated whilst the mTOR/S6K/S6 pathway was enhanced in MCSEKO mice. These effects were reversed by the H2S supplement. Aerobic treadmill training significantly promoted glucose tolerance and insulin sensitivity and improved GLU4 and PKG-1 levels, promoted IRS1/PI3K/Akt signaling and suppressed mTOR/S6K/S6 signaling pathway in MCSEKO mice. Our data suggest that skeletal muscle CSE/H2S signaling is critical for the maintenance of insulin sensitivity, which is associated with maintaining the balance in PKG, PI3K/Akt, and mTOR/S6K/S6 signaling pathways in skeletal muscle. [ABSTRACT FROM AUTHOR]