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Diaryldithiocarbamate complexes, [Fe(S[sub.2]CNAr[sub.2])[sub.3]], have been prepared and their structure, reactivity, and thermal degradation to afford iron sulfide nanomaterials have been investigated. The addition of three equivalents of LiS[sub.2]CNAr[sub.2] to FeCl[sub.2]·4H[sub.2]O in water-air affords dark red [Fe(S[sub.2]CNAr[sub.2])[sub.3]] in high yields. All show magnetic measurements consistent with a predominantly high-spin electronic arrangement at room temperature. The molecular structure of [FeS[sub.2]C(N-p-MeOC[sub.6]H[sub.4])[sub.2][sub.3]] reveals the expected distorted octahedral geometry, but Fe-S distances are more consistent with a low-spin electronic configuration, likely a result of the low temperature (120 K) of the data collection. The thermal stability of [FeS[sub.2]C(N-p-MeC[sub.6]H[sub.4])[sub.2][sub.3]] has been investigated. TGA shows that it begins to decompose at a significantly lower temperature (ca. 160 °C) than previously observed for [Fe(S[sub.2]CNEt[sub.2])[sub.3]], and this is further lowered (to ca. 100 °C) in oleylamine. The decomposition of [FeS[sub.2]C(N-p-MeC[sub.6]H[sub.4])[sub.2][sub.3]] in oleylamine, via either a heat-up or hot injection process, affords nanoparticles of Fe[sub.3]S[sub.4] (greigite), while in contrast, dry heating at 450 °C affords FeS (troilite) as large agglomerates.

Hydrogen sulphide (H₂S) is an endogenously produced gasotransmitter that has rapidly emerged as an active signalling component of several plant processes, stomatal movement regulation among them. The guard cells (GCs), pairs of cells that neighbour the stomatal pores, transduce endogenous and environmental signals, through signalling network, to control stomatal pore size. In this complex network, which has become a model system for plant signalling, few highly connected components form a core that links most of the pathways. The evidence summarized in this insight, on the interplay between H₂S and different key components of the GC networks, points towards H₂S as a regulator of the GC core signalling pathway.

• Hydrogen sulphide (H₂S) has been proposed as the third gasotransmitter. In animal cells, H₂S has been implicated in several physiological processes. H₂S is endogenously synthesized in both animals and plants by enzymes with l‐Cys desulphydrase activity in the conversion of l‐Cys to H₂S, pyruvate and ammonia. • The participation of H₂S in both stomatal movement regulation and abscisic acid (ABA)‐dependent induction of stomatal closure was studied in epidermal strips of three plant species (Vicia faba, Arabidopsis thaliana and Impatiens walleriana). The effect of H₂S on stomatal movement was contrasted with leaf relative water content (RWC) measurements of whole plants subjected to water stress. • In this work we report that exogenous H₂S induces stomatal closure and this effect is impaired by the ATP‐binding cassette (ABC) transporter inhibitor glibenclamide; scavenging H₂S or inhibition of the enzyme responsible for endogenous H₂S synthesis partially blocks ABA‐dependent stomatal closure; and H₂S treatment increases RWC and protects plants against drought stress. • Our results indicate that H₂S induces stomatal closure and participates in ABA‐dependent signalling, possibly through the regulation of ABC transporters in guard cells.

The extent to which sulfur dissolves in silicate melts saturated in an immiscible sulfide phase is a fundamental question in igneous petrology and plays a primary role in the generation of magmatic ore deposits, volcanic degassing, and planetary differentiation. In igneous systems, sulfide melts can be described as FeS-NiS-CuS0.5 solutions with Fe/(Fe+Ni+Cu) significantly less than 1. Despite the presence of Ni and Cu in the sulfide, however, most experimental studies to date have concentrated on the effects of silicate melt composition on sulfur solubility and have used essentially pure FeS as the sulfide liquid. We have carried out 49 new experiments at pressures of 1.5-24 GPa and temperatures of 1400 to 2160 °C to investigate the effects of sulfide composition on sulfur solubility as well as extending the pressure and temperature ranges of the available data on sulfide saturation. We find that in the compositional range of most igneous sulfide melts [Fe/(Fe+Ni+Cu) > 0.6] sulfur solubility decreases linearly with Fe content such that at Fe/(Fe+Ni+Cu) of 0.6 the sulfur content at saturation is 0.6 times the value at pure FeS saturation. At lower values of Fe/(Fe+Ni+Cu), however, deviations from this ideal solution relationship need to be taken into consideration. We have treated these non-idealities by assuming that FeS-NiS-CuS0.5 liquids approximate ternary regular solutions.We have fitted our data, together with data from the literature (392 in total), to equations incorporating the effects of silicate melt composition, sulfide liquid composition, and pressure on the solubility of sulfur at sulfide saturation ([S]SCSS). The temperature dependence of [S]SCSS was assumed either to be an unknown or was taken from 1 bar thermodynamic data. The most important best-fit silicate melt compositional term reflects the strongly positive dependence of [S]SCSS on the FeO content of the silicate melt. The best-fit value of this parameter is essentially independent of our assumptions about temperature dependence of [S]SCSS or the solution properties of the sulfide. All natural compositions considered here exhibit positive dependences of [S]SCSS on temperature and negative dependences on pressure, in accord with previous studies using smaller data sets.

Microbial inoculation is a commonly applied approach in composting to enhance organic matter biodegradation and reduce odor emissions. However, the different characteristics of bacteria in terms of temperature can be considered to optimize their effect during different phases of composting. A mesophilic bacterium, namely Aquamicrobium lusatiense NLF 2–7, was evaluated to mitigate odor emissions and enhance the bacterial community under mesophilic composting. Two different treatments were designed: treatment 1 with a single inoculation on the initial day and treatment 2 with split inoculation at the initial and after 2 weeks. Results show that the treatments improve organic matter decomposition by 17.7–28.6% and significantly reduce volatile sulfur compound emissions, especially dimethyl sulfide (DMS) and hydrogen sulfide (H 2 S) during the initial phase of composting. DMS emissions were mostly emitted in the first week, with reduction rates of 60.3% and 61.5% in both treatments, respectively. Additionally, mean phenol emissions were reduced by 7.9% in treatment 1 and 11.7% in treatment 2. The dominant bacterial phyla during composting were Bacillota , Pseudomonadota , Bacteroidota , and Actinomycetota , comprising 74 to 95% of the total population. This experiment suggests that A. lusatiense NLF 2–7, which is known for reducing sulfur emissions, can also enhance organic matter decomposition. Split inoculation appears more beneficial, with an initial inoculation managing sulfur emissions early on, followed by a second inoculation after the thermophilic phase to control phenol emissions throughout the composting process.

Abnormal sulfide catabolism, especially the accumulation of hydrogen sulfide (H2S) during hypoxic or inflammatory stresses, is a major cause of redox imbalance-associated cardiac dysfunction. Polyhydroxynaphtoquinone echinochrome A (Ech-A), a natural pigment of marine origin found in the shells and needles of many species of sea urchins, is a potent antioxidant and inhibits acute myocardial ferroptosis after ischemia/reperfusion, but the chronic effect of Ech-A on heart failure is unknown. Reactive sulfur species (RSS), which include catenated sulfur atoms, have been revealed as true biomolecules with high redox reactivity required for intracellular energy metabolism and signal transduction. Here, we report that continuous intraperitoneal administration of Ech-A (2.0 mg/kg/day) prevents RSS catabolism-associated chronic heart failure after myocardial infarction (MI) in mice. Ech-A prevented left ventricular (LV) systolic dysfunction and structural remodeling after MI. Fluorescence imaging revealed that intracellular RSS level was reduced after MI, while H2S/HS− level was increased in LV myocardium, which was attenuated by Ech-A. This result indicates that Ech-A suppresses RSS catabolism to H2S/HS− in LV myocardium after MI. In addition, Ech-A reduced oxidative stress formation by MI. Ech-A suppressed RSS catabolism caused by hypoxia in neonatal rat cardiomyocytes and human iPS cell-derived cardiomyocytes. Ech-A also suppressed RSS catabolism caused by lipopolysaccharide stimulation in macrophages. Thus, Ech-A has the potential to improve chronic heart failure after MI, in part by preventing sulfide catabolism.

With the rapid development of nanotechnology, metal sulfide nanoparticles have been widely detected in the environment including water, soils and sediments. Metal sulfides are considered as stable species in the environment, while transformation and risk of nanoparticles have attracted increasing attention due to their specific physicochemical properties compared to bulk materials. Here we review aggregation, sedimentation, chemical and biological transformations, and potential risk of silver sulfide (Ag2S), zinc sulfide (ZnS), copper sulfide (CuS), cadmium sulfide (CdS) and lead sulfide nanoparticles, and quantum dots such as ZnS and CdS. The review shows that both stability and risk of metal sulfide nanoparticles are highly dependent on environmental factors such as pH, inorganic salts and natural organic matter.

Growth media have been developed to facilitate the enrichment and isolation of acidophilic and acid-tolerant sulfate-reducing bacteria (aSRB) from environmental and industrial samples, and to allow their cultivation in vitro. The main features of the ‘standard’ solid and liquid devised media are as follows: (i) use of glycerol rather than an aliphatic acid as electron donor; (ii) inclusion of stoichiometric concentrations of zinc ions to both buffer pH and to convert potentially harmful hydrogen sulphide produced by the aSRB to insoluble zinc sulphide; (iii) inclusion of Acidocella aromatica (an heterotrophic acidophile that does not metabolize glycerol or yeast extract) in the gel underlayer of double layered (overlay) solid media, to remove acetic acid produced by aSRB that incompletely oxidize glycerol and also aliphatic acids (mostly pyruvic) released by acid hydrolysis of the gelling agent used (agarose). Colonies of aSRB are readily distinguished from those of other anaerobes due to their deposition and accumulation of metal sulphide precipitates. Data presented illustrate the effectiveness of the overlay solid media described for isolating aSRB from acidic anaerobic sediments and low pH sulfidogenic bioreactors. The paper describes how bacteria that live in acidic environments, and that form hydrogen sulphide from sulfate, may be isolated and grown in the laboratory. Graphical Abstract Figure. The paper describes how bacteria that live in acidic environments, and that form hydrogen sulphide from sulfate, may be isolated and grown in the laboratory.

Central nervous system (CNS)-related conditions are currently the leading cause of disability worldwide, posing a significant burden to health systems, individuals and their families. Although the molecular mechanisms implicated in these disorders may be varied, neurological conditions have been increasingly associated with inflammation and/or impaired oxidative response leading to further neural cell damages. Therefore, therapeutic approaches targeting these defective molecular mechanisms have been vastly explored. Hydrogen sulphide (H2S) has emerged as a modulator of both inflammation and oxidative stress with a neuroprotective role, therefore, has gained interest in the treatment of neurological disorders. H2S, produced by endogenous sources, is maintained at low levels in the CNS. However, defects in the biosynthetic and catabolic routes for H2S metabolism have been identified in CNS-related disorders. Approaches to restore H2S availability using H2S-donating compounds have been recently explored in many models of neurological conditions. Nonetheless, we still need to elucidate the potential for these compounds not only to ameliorate defective biological routes, but also to better comprehend the implications on H2S delivery, dosage regimes and feasibility to successfully target CNS tissues. Here, we highlight the molecular mechanisms of H2S-dependent restoration of neurological functions in different models of CNS disease whilst summarising current administration approaches for these H2S-based compounds. We also address existing barriers in H2S donor delivery by showcasing current advances in mediating these constrains through novel biomaterial-based carriers for H2S donors.

Experimental studies on binary, ternary and quaternary Cu–Fe–Ni–S systems are fundamental for the investigation of magmatic sulfide deposits, the main source of Ni, Co and platinum group elements (PGE). Previous experimental studies successfully formulated our general understanding of the evolution of magmatic sulfide systems but, yet, in many cases could not explain some of the key geological, mineralogical and geochemical features of sulfide ore deposits. The challenges are imposed by not well-defined solidus of the Cu-rich sulfide melts, yet poorly constrained phase stability at subliquidus conditions, and poorly resolved subsolidus evolution of magmatic sulfide phases. In this study we aim at better understanding how base metal sulfides crystallize from the evolving sulfide liquid during cooling from superliquidus to room temperatures. We report on controlled cooling (15 °C/day) experiments from 1100 to 25 °C in evacuated silica tubes of a single composition of the quaternary Cu–Ni–Fe–S system similar to the Merensky Reef sulfide ore. Run products were sampled at various temperatures along the cooling path and examined on the microscopic scale by back scattered electron imaging and on the nanometer scale by transmission electron microscopy. The compositions of coexisting phases were analysed using electron microprobe. We show that the sulfide melt (SM) coexists with monosulfide solid solution (MSS) above 950 °C and persists to 700 ± 25 °C before it crystallizes to intermediate solid solution (ISS). The transition to subsolidus state is clearly traced by abrupt change in the Cu/(Fe + Ni) distribution between MSS and Cu-rich phase (either SM or ISS) and in the composition of SM or ISS. The compositional jump at ca. 700 °C is also accompanied by the inverse change in the proportions of coexisting phases indicating significant subsolidus reactions and evolution with decreasing temperature. Pentlandite commences crystallization around MSS grains between 550 and 450 °C and coarsens to a granular-type pentlandite at 450 °C by diffusion of nano pentlandite exsolutions from MSS. Pentlandite exsolves and grows as “flames” and “brushes” in both MSS and ISS at lower temperatures (< 250 °C). Mass balance calculations suggest that 32% of pyrrhotite and 7% of pentlandite in magmatic deposits like the Merensky Reef exsolve from ISS. Results imply that magmatic sulfide systems evolve to lower temperatures than previously thought, leading to significant ore metal fractionation and redistribution. Base metal sulfide phases re-equilibrate extremely fast during cooling, ensuring that primary phase compositions and textures are inevitably and completely eradicated during cooling histories even as short as a few days. The sulfide mineral assemblage, texture and modal abundance of magmatic sulfide phases could be used as a proxy for the reconstruction of the parent sulfide liquid evolution in the deposit. The newly established mechanism and timing of base metal sulfides crystallization provides possible explanation of PGE distribution in base metal sulfides.