Role Of Sulfur Research Articles

Biological and Structural Evaluation of 10R- and 10S-Methylthio-DDACTHF Reveals a New Role for Sulfur in Inhibition of Glycinamide Ribonucleotide Transformylase

Glycinamide ribonucleotide transformylase (GAR Tfase) is a folate-dependent enzyme in the de novo purine biosynthesis pathway, which has long been considered a potential target for development of anti-neoplastic therapeutics. Here we report the biological and X-ray crystallographic evaluations of both independent C10 diastereomers, 10S- and 10R-methylthio-DDACTHF, bound to human GAR Tfase, including the highest-resolution apo GAR Tfase structure to date (1.52 Å). Both diastereomers are potent inhibitors (Ki = 210 nM for 10R, and Ki = 180 nM for 10S) of GAR Tfase and exhibit effective inhibition of human leukemia cell growth (IC₅₀ = 80 and 50 nM, respectively). Their inhibitory activity was surprisingly high, and these lipophilic C10-substituted analogues show distinct advantages over their hydrophilic counterparts, most strikingly in retaining potency in mutant human leukemia cell lines that lack reduced folate carrier protein activity (IC₅₀ = 70 and 60 nM, respectively). Structural characterization reveals a new binding mode for these diastereoisomers, in which the lipophilic thiomethyl groups penetrate deeper into a hydrophobic pocket within the folate-binding site. In silico docking simulations of three other sulfur-containing folate analogues also indicate that this hydrophobic cleft represents a favorable region for binding lipophilic substituents. Overall, these results suggest sulfur and its substitutions play an important role in not only the binding of anti-folates to GAR Tfase but also the selectivity and cellular activity (growth inhibition), thereby presenting new possibilities for the future design of potent and selective anti-folate drugs that target GAR Tfase.

Effect of sulfur and copper amounts in sol–gel precursor solution on the growth, crystal properties, and optical properties of Cu2ZnSnS4 films

Cu2ZnSnS4 (CZTS) thin films were deposited by sol–gel spin coating using precursor solutions prepared with copper acetate, zinc acetate, tin chloride, and thiourea in methanol and ethylenediamine followed by sulfurization. Sol–gel precursor solutions were prepared with different amounts of sulfur and copper, and their effects on film growth, crystal properties, and optical properties of CZTS films were investigated. CZTS film thickness increased with the amount of metal salt in the precursor solution. This is attributed to an increase in solution viscosity and a decrease in the solution density/viscosity ratio. All CZTS thin films exhibited kesterite structures with absorption coefficients larger than 104 cm−1 in the visible region. Band gap energy increased with increasing amounts of sulfur and decreasing amounts of copper. The blue shift of the band gap is attributed to changes in the degree of p–d hybridization related to Cu d- and S p-levels. The role of sulfur and copper on Hall mobility and carrier concentration was investigated. By optimizing the metal salt ratio in the precursor, CZTS film with a resistivity of 5.3 × 10−2 Ωcm were prepared.

Chemical species of sulfur in prostate cancer cells studied by XANES spectroscopy

The role of sulfur in prostate cancer progression may be significant for understanding the process of carcinogenesis. This work, based on X-ray Absorption Near Edge Structure (XANES) spectroscopy, is focused on determination of sulfur chemical species occurring in prostate cancer cell lines. The experimental material consisted of four commercially available cell lines: three from metastasized prostate cancer (PC3, LNCaP, and DU145) and one, used as a control, from the non-tumourigenic peripheral zone of the prostate (PZ-HPV-7). The experiment was performed at the SUL-X beamline of the synchrotron radiation source ANKA, Karlsruhe (Germany). The K-edge XANES spectra of sulfur were analyzed by deconvolution in order to establish sulfur species that occur in prostate cancer cells and to find out whether there are any differences in their content between various cell lines. Experimental spectra were fitted in two ways: with two Gaussian peaks and one arctangent step function, and additionally by a Linear Combination Fit with spectra of reference compounds in order to obtain quantitative chemical information. All fitting procedures were performed with the Athena code (Ravel and Newville, 2005) and the results of deconvolution were used to determine the fraction of each sulfur form. The results of data analysis showed that cell lines from different metastasis had different ratio of reduced to oxidized sulfur species. The LCF analysis demonstrated that the highest content of GSH, one of the most important sulfur-bearing compounds in cells, was observed in DU145 cells. These findings may confirm the hypothesis of changes in redox balance in case of cancer initiation and progression.

Thermal features and physical properties of sulfur modified barium vanadate glasses

Differential scanning calorimetry (DSC) and XRD were used to investigate the role of sulfur in the network of V2O5–Fe2O3–BaO glasses. The crystallization kinetics of the glasses were investigated under non-isothermal conditions applying the formal theory of transformations for heterogeneous nucleation to the experimental data obtained by DSC. The activation energy for the glass transition (E g) was derived from dependence of the glass-transition temperature (T g) on the heating rate. Similarly the activation energy of the crystallization (E c) and the frequency factor (K 0) were determined. The results reveal the increase of the activation energy for glass transition was attributed to the increase in the rigidity and the cross-link density of these composites. The evaluated thermal stability decreases with increasing sulfur content. The phases of BaFe2O4, V2O5 and FeVO4 micro-crystallites in the remaining amorphous matrix have been identified by X-ray diffraction.

Mild and Selective Organocatalytic Iodination of Activated Aromatic Compounds

We describe an organocatalytic iodination of activated aromatic compounds using 1,3-diiodo-5,5-dimethylhydantoin (DIH) as the iodine source with thiourea catalysts in acetonitrile. The protocol is applicable to a number of aromatic substrates with significantly different steric and electronic properties. The iodination is generally highly regioselective and provides high yields of isolated products. NMR kinetic investigations conducted in THF-d 8 indicate the role of sulfur in the thiourea motif as a nucleophile that is assisted by H-bonding in the key steps of the reaction.

Synthesis, crystal structures and non-bonded S···S contacts with O‒H···O/O‒H···S hydrogen bonds in isomeric hydroxyphenyl-1,3-dithianes

The synthesis of isomeric hydroxyphenyl-1,3-dithianes and the role of sulfur in them to generate different engineered solids based on non-bonded O···S contacts and O‒H···S hydrogen bonds are presented. With an increasing number of OH groups and dithiane rings (e.g. 2, 3), the role of O‒H···S interactions becomes less prominent and the strong O‒H···O hydrogen bonds along with C‒H···π and π–π stacking interactions dominate the packing arrangement of the hydroxyphenyl-1,3-dithianes.

The solubility of palladium and ruthenium in picritic melts: 2. The effect of sulfur

The platinum-group elements (PGE) are exceptional tracers of planetary differentiation and therefore are useful discriminants of different high-temperature processes. Many of the initial efforts to understand how PGE behave during mantle melting involved experiments where PGE solubility in silicate melt was measured. The results of these experiments showed that PGE dissolve in silicate melts as oxide species, and that their saturation depends on oxygen partial pressure (pO2). However, the majority of these experimental studies were conducted on FeO and sulfur-free melt compositions that little resemble natural magmas. In particular, the role of sulfur has been downplayed because of its lower availability as a ligand to the PGE in silicate melt when compared to oxygen. However, magmatic sulfides from oceanic basalts and layered intrusions are greatly enriched in the PGE relative to the silicate melts in equilibrium with them, suggesting that the PGE are strongly chalcophile. The question then is whether the PGE are actively scavenged into sulfide melt after it exsolves from a silicate melt; or if the PGE are already associated with S2− in a silicate melt prior to sulfide saturation.Here we report the results of experiments where the solubilities of Ru and Pd have been measured in natural picritic melt, as a function of pO2 and in the presence of sulfur. Results show that the presence of sulfur in the silicate melt enhances the solubility of Ru in picrite by over an order of magnitude. These results can be used to quantify the preference that PGE have to associate with sulfur relative to oxygen. For example, Ru was found to be 880±410 times more likely to associate with sulfur than with oxygen at pO2 around the fayalite–magnetite–quartz redox equilibrium. The preferential association of the PGE with S2− ligand indicates that once a sulfide melt exsolves, it will already be enriched in PGE precluding the need for it to actively scavenge PGE from a silicate melt.

Role of Sulfur on the Transition from Graphite to Cementite Eutectic in Cast Iron

In the current study, an analytic solution is considered to explain the influence of sulfur on the transition from graphite to cementite eutectic in cast iron. The outcome from the current study indicates that this transition can be related to (a) the graphite nucleation potential (directly characterized by the cell count and indirectly by the nucleation coefficients; (b) the eutectic graphite growth rate coefficient; (c) the temperature range between the equilibrium temperature for graphite eutectic and the formation temperature for cementite eutectic; and (d) the liquid volume fraction, after pre-eutectic austenite solidification. In addition, the absolute and the relative chilling tendencies, as well as critical cooling rates including the chill width of the cast iron can be predicted from the current study. The analytic model was experimentally verified for castings with various sulfur contents. It is found that the main role of sulfur on the transition from graphite to cementite eutectic is through its effect on lowering the growth coefficient, and hence, the graphite eutectic growth rate. In addition, it is found that with the increasing sulfur content, the critical cooling rate is significantly reduced, thus increasing the absolute and the relative chilling tendency values, including the chill width.

Oxide Trapping in the InGaAs–$\hbox{Al}_{2} \hbox{O}_{3}$ System and the Role of Sulfur in Reducing the $ \hbox{Al}_{2}\hbox{O}_{3}$ Trap Density

Trap spectroscopy by charge injection and sensing method was applied to the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX"> $\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}{-}\hbox{Al}_{2}\hbox{O}_{3}$</tex></formula> system, yielding the spatial and energetic distribution of the traps inside the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{Al}_{2}\hbox{O}_{3}$ </tex></formula> layer. The trap density inside the atomic-layer-deposited (ALD) <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX"> $\hbox{Al}_{2}\hbox{O}_{3}$</tex></formula> layer was found to be significantly reduced by <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$(\hbox{NH}_{4})_{2}\hbox{S}$</tex></formula> treatment of the InGaAs surface prior to the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{Al}_{2}\hbox{O}_{3}$</tex></formula> deposition. Indium concentration inside the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{Al}_{2}\hbox{O}_{3}$</tex></formula> layer was found to be reduced once the InGaAs surface is <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$(\hbox{NH}_{4})_{2}\hbox{S}$</tex> </formula> treated prior to the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{Al}_{2}\hbox{O}_{3}$</tex></formula> deposition as measured by time-of-flight secondary ion mass spectroscopy, indicating indium as a possible origin of the oxide traps. The results suggest a new mechanism for the sulfur action at the InGaAs surface, which might be responsible for the transistor performance improvements observed after <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$( \hbox{NH}_{4})_{2}\hbox{S}$</tex></formula> passivation. This mechanism involves sulfur as an indium diffusion/segregation barrier stabilizing the InGaAs surface during the ALD <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$ \hbox{Al}_{2}\hbox{O}_{3}$</tex></formula> deposition, lowering the oxide trap density. This, in turn, improves the electron mobility through a reduction in the Coulomb scattering of the carriers due to border traps and improves the device drive current.

The Role of Sulfur in Solution‐Processed Cu2ZnSn(S,Se)4 and its Effect on Defect Properties

AbstractUnderstanding the electrically active defects in kesterite Cu2ZnSn(S,Se)4(CZTSSe) is critical for the continued development of solar cells based on this material, but challenging due to the complex nature of this polycrystalline multinary material. A comparative study of CZTSSe alloys with three different bandgaps, made by introducing different fractions of sulfur during the annealing process, is presented. Using admittance spectroscopy, drive level capacitance profiling, and capacitance‐voltage profiling, the dominant defect energy level present in the low sulfur content device is determined to be 0.134 eV above the valence band maximum, with a bulk defect density of 8 × 1014 cm−3, while the high sulfur content device shows a deeper defect energy level of 0.183 eV and a higher bulk defect density, 8.2 × 1015 cm−3. These findings are consistent with the current density–voltage characteristics of the resulting solar cells and their external quantum efficiency. It suggests that as the sulfur content increases, the bandgap of the absorber is enlarged, leading to an increasing open‐circuit voltage (Voc), that is accompanied by stronger recombination due to the higher defect density of the sulfur‐rich absorber. This is reflected in large Voc deficit and poor carrier collection of the high sulfur content device.

On the Organocatalytic Activity of N-Heterocyclic Carbenes: Role of Sulfur in Thiamine

The reaction energy profiles of the benzoin condensation from three aldehydes catalyzed by imidazol-2-ylidene, triazol-3-ylidene, and thiazol-2-ylidene have been investigated computationally. The barriers for all steps of all investigated reactions have been found to be low enough to indicate the viability of the mechanism proposed by Breslow in the 1950s. The most remarkable difference in the catalytic cycles has been the increased stability of the Breslow intermediate in case of thiazol-2-ylidene (by ca. 10 kcal/mol) compared to the other two carbenes, which results in lower energy for the coupling of the second aldehyde molecule, thus, increasing the reversibility of the reaction. Since the analogous transketolase reaction, being involved in the carbohydrate metabolism of many organisms, requires an initial decoupling-a reverse benzoin condensation-this difference provides a reasonable explanation for the presence of a thiazolium ring in thiamine instead of the otherwise generally more available imidazole derivatives. The "resting intermediate" found by Berkessel and co-workers for a triazole-based catalyst was found more stable than the Breslow intermediate for all of the systems investigated. The (gas phase) proton affinities of several carbenes were compared, the relative trends being in agreement with the available (in aqueous solution) data. The hydrolytic ring-opening reaction of the thiazole-based carbene was shown to be different from that of imidazole-2-ylidenes.

Measurement of Near Ultrafine S Aerosol at a Semiarid Region in India

The sulphur containing particles play an important role in climate change, radiative forcing, global warming and public health. The present investigation deals with measurements of near ultrafine sulphur particles viz., sulphur as SO4 2− and free sulphuric acid at Dayalbagh, Agra which is a suburban site in India to assess the role of sulphur containing nanoparticles. The concentration of near ultrafine SO4 2− and free H2SO4 are 530 and 40 ng m−3, respectively. The contribution of ultrafine sulphate is 25 % towards total sulphate in ambient aerosol of this region while ultrafine free sulphuric acid contributes about 16.6 % towards total free sulphuric acid. Atmospheric ultrafine S particles (UFP) are formed from gases by a homogeneous oxidation of sulphur dioxide to sulphuric acid. Although the UFP mass fraction is usually very small but because of their increased number and surface area these ultrafine particles are particularly important in atmospheric processes.

Separation of Molybdenum and Copper in Porphyry Deposits: The Roles of Sulfur, Redox, and pH in Ore Mineral Deposition at Bingham Canyon

The giant Bingham Canyon porphyry Cu-Mo-Au deposit (Utah) is associated with Eocene subvolcanic intrusions. It shows a distinct metal zonation above a barren core, with dominantly shallow Cu-Au mineralization (Cu stage) following the early quartz monzonite porphyry (QMP) intrusion, and spatially deeper Mo mineralization (Mo stage) occurring in a separate vein set exclusively after a late quartz latite porphyry (QLP) intrusion that truncates earlier Cu-Au veins. To understand this metal separation and the geochemical process of molybdenite mineralization, we investigated fluid inclusions by microthermometry, Raman spectroscopy, and laser ablation inductively couple plasma mass spectrometry (LA-ICP-MS) microanalysis in low- and high-grade quartz veins of both mineralization stages. In deep, low-grade quartz veins interpreted to represent the root zone of the Cu stage we found high concentrations of Cu, S, and Mo in the fluid inclusions, whereas in low-grade Mo-stage veins, we found lower Cu, but similar concentrations of S and Mo, compared to the inferred input fluids to the Cu stage. Sulfur and copper concentrations were similar in intermediate-density-type fluid inclusions in deep low-grade Cu-stage samples, whereas intermediate-density-type inclusions in low-grade Mo-stage veins have S contents that exceed their Cu contents. In high-grade Mo-stage vein, we found large variations of Mo concentrations in coexisting brine and vapor inclusions. Compared to the P-T conditions of the Cu precipitation stage (90–260 bars and 320°–430°C), the Mo-precipitating fluids were trapped at higher pressures and temperatures of 140 to 710 bars and 360° to 580°C. Mass-balance calculation based on the compositions of intermediate-density inclusions and brine + vapor assemblages, interpreted to be derived by phase separation during decompression of the ascending single-phase intermediate-density fluid, indicate that the mass of vapor phase exceeded that of brine by about 9:1 in both mineralization stages. Combining this mass balance with the analyzed vapor/brine partitioning data indicates that more than 70% of Mo and S (by mass) in the deposit were deposited from the vapor phase. Earlier Cu-Au deposition was similarly dominated by vapor, but recently published data about postentrapment Cu diffusion in and out of fluid inclusions cast doubt on previous quantifications, suggesting that almost none of the copper was deposited by brine. Mo is less likely to be modified by selective diffusion, and high Mo contents (max 0.0054 Mo/Na in intermediate density; 380 μ g/g Mo in brine) in the hydrothermal fluids were maintained from the early Cu stage to the late Mo stage. This indicates that Mo concentration was not the decisive factor for separate precipitation of late Mo ore at Bingham Canyon. Instead, the metal separation may be explained by a reduction in redox potential and an increase in acidity in the evolving source region of the fluids, i.e., a large subvolcanic magma reservoir. This is indicated by the stoichiometry of chalcopyrite and molybdenite precipitation reactions, a tentative difference in the Fe/Mn ratio in fluids of both veining stages, incipient muscovite alteration along high-temperature molybdenite veins, and an increasing tendency for Mo to fractionate from brine to vapor. We suggest that the early Cu-stage fluids were slightly more oxidized and neutral, allowing Cu-Fe sulfides to saturate first, while molybdenite saturation was suppressed and Mo was lost from the early ore stage. By contrast during the later Mo stage, the fluids were more reduced and acidic, thereby allowing selective saturation of molybdenite as the first precipitating sulfide in the cooling and expanding two-phase fluid, consistent with textural observations. This interpretation may imply more generally that small differences in redox potential and acid/base balance of the magmatic source of porphyry-mineralizing systems may be decisive in the temporal and spatial separation of the two metals.

A one-pot hydrothermal synthesis of tunable dual heteroatom-doped carbon microspheres

In terms of broadening the potential application range of carbon based materials, heteroatom doping provides a useful tool to moderate their physical and chemical properties. While nitrogen doped carbons have been extensively researched, the reports for sulfur, and especially nitrogen/sulfur dual-doped materials is far less exhaustive. We present a one-pot synthesis of dual nitrogen/sulfur doped materials which is based on sustainable carbohydrate and amino acid precursors and enables tailoring of the final material's physicochemical properties. The addition of cysteine gives rise to pending sulfur functionalities, while addition of thienyl-cysteine results in structurally bound sulfur within the carbonaceous framework. Post pyrolysis offers an additional tool for controlling the material stability and results in microporosity as well as superior conductivity relative to undoped carbon microspheres from glucose. Nitrogen doping levels of about 4 wt% and sulfur doping levels of 3 wt% to 12 wt% could be achieved. The samples were, amongst other methods, characterized by XPS, 13C MAS solid state NMR and both N2 and CO2 sorption isotherms. Since this is the first report on heteroatom doped, sulfur containing carbon materials obtained via hydrothermal carbonization, we anticipate our work to be a starting point for more sophisticated studies concerning the role of sulfur (and nitrogen) on the physicochemical properties of hydrothermal carbon.

Tomography: A window on the role of sulfur in the structure of micrometeorites

Abstract– To determine the role played by sulfides in the formation of vesicles and FeNi metal beads, we mapped the locations and tabulated the numbers of sulfides, metal beads, and vesicles in 1583 sectioned micrometeorites (MMs) using conventional microscopy and in 190 whole MMs using synchrotron computed microtomography (SCMT). Both the section and the SCMT images show that sulfides melt, coalesce, and migrate to the MMs surface. The decomposition of sulfides may occur during all these stages. Given the sulfide morphologies and compositions that we see in section, we think the breakdown of Ni sulfides produces the FeNi beads. The SCMT images show that metal beads are common in melted MMs, &gt;50% have them. Vesicles in porphyritic and scoriaceous MMs are also probably formed as sulfides decompose. Not only do sulfides abut the vesicles but also the temperatures at which sulfides decompose overlap those at which MM surfaces first melt and temporarily seal, suggesting that S gases could produce most of these vesicles. As the vesicle shapes and patterns of distribution differ among MM classes, tomography can be used to nondestructively screen for specific types of MMs. Tomography is a powerful tool for visualizing the three‐dimensional distribution of metal beads, sulfides, mean densities, and vesicles in MMs.

Role of Sulfur and Its Diffusion in Silicate Glass Melts

Sulfur diffusion DS is reported on a technical alkali‐poor barium alumoborosilicate glass melt at 900–1400°C and on three further Na2O‐modified glass melts at 900°C, using a radioactive tracer method. Whereas DS for the base glass melt amounts to ≈1 × 10−15m2/s at 900°C, it increases nearly exponentially with increasing Na2O content from 0 to 15 mol% by almost three orders of magnitude. Similar to other glass melts, the sulfur diffusion obtained in these melts is also closely related to the Eyring diffusivity Dn derived from viscosity. The diffusion controlling species in oxidized melts seems to be SO42−, in reduced melts S2−. SO32− does obviously not play any role in this transport process.

Enhancement of Copper Availability and Microbial Community Changes in Rice Rhizospheres Affected by Sulfur

The role of sulfur on the availability of Cu and the bacterial community in rice rhizospheres was investigated by pot experiments. With sulfur addition, pH in rhizosphere soil decreased and Mg(NO3)2 extractable Cu increased significantly. The bacterial community composition also changed with sulfur addition. Some specific clones having high similarity to Thiobacillus, which indicated that sulfur oxidation in the rice rhizosphere could increase the availability of Cu. These results suggested that sulfur source which could provide substrate to sulfur oxidizing bacteria and enhance the availability of Cu was not a suitable sulfur fertilizer for Cu polluted soil.

Experimental Studies on Sulfur Solubility in Silicate Melts at Near-Atmospheric Pressure

Various experimental studies in silicate melts have been performed to understand the dependence of sulfur solubility on melt composition and experimental conditions. These experiments were motivated by glass technologists due to the role swulfur compounds play in fining (Muller-Simon 2011, this volume) and coloring (Falcone et al. 2011, this volume) melts. In particular, the risk of foaming in the glass tank and rejects in the glass production due to discoloration and bubbles demand a systematic approach for sulfur solubility in silicate melts. Also sulfur solubility experiments have been conducted by metallurgists, whose interest is centered on the interaction of metal and slag melts to desulfurize steel products (Lehmann and Nadif 2011, this volume). Besides technical applications, sulfur solubility experiments at atmospheric pressure are of importance to geoscientists in modelling near-surface conditions such as sulfur degassing from volcanoes (Oppenheimer et al. 2011, this volume) and the role of sulfur in the formation of ore deposits (Simon and Ripley 2011, this volume). In order to study the effect of polymerization of the silicate network on sulfur solubility, melt compositions were varied in the experiments across broad limits. It has been shown that the solubility generally increases with increasing network modifier to network former ratio (Baker and Moretti 2011, this volume). This supports the idea that the presence of free volume and cationic charge compensators in the network structure promote incorporation and mobility of anionic sulfur species (Behrens and Stelling 2011, this volume). Sulfur speciation is also responsible for the strong dependence of sulfur solubility on oxygen fugacity as reported by Baker and Moretti (2011, this volume) and Muller-Simon (2011, this volume) for natural and technical melts, respectively. Sulfur was found to be stable in these melts as sulfide S2− under reducing conditions …

Sulfur in Extraterrestrial Bodies and the Deep Earth

Research Article| January 01, 2011 Sulfur in Extraterrestrial Bodies and the Deep Earth Denton S. Ebel Denton S. Ebel Department of Earth and Planetary Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, U.S.A., debel@amnh.org Search for other works by this author on: GSW Google Scholar Reviews in Mineralogy and Geochemistry (2011) 73 (1): 315–336. https://doi.org/10.2138/rmg.2011.73.11 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Denton S. Ebel; Sulfur in Extraterrestrial Bodies and the Deep Earth. Reviews in Mineralogy and Geochemistry 2011;; 73 (1): 315–336. doi: https://doi.org/10.2138/rmg.2011.73.11 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyReviews in Mineralogy and Geochemistry Search Advanced Search This chapter reviews the origin and fate of sulfur (S) in silicate melts in the solar system, experiments bearing on the role of S in element partitioning among melts and solids in planets, and finally our current understanding of silicate melts and the role of sulfur in planetary evolution. Sulfur is an important component of undifferentiated meteorites that are precursors to planets. When planetary bodies differentiated into cores and mantles, metal and/or sulfides were removed from silicates. This process can be traced. Then, iron-sulfide cores differentiated into metal and metal-sulfide fractions, some of which are preserved as iron meteorites. The... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Chromate toxicity and the role of sulfur

The molecular mode(s)-of-action of the toxic metal chromium has yet to be fully resolved. This Mini review focuses on interactions between chromate and sulfur in biological systems. Cr binds sulfur ligands, with cysteine and glutathione having the capacity to aggravate or ameliorate Cr toxicity. Competition between chromate and sulfate for uptake and in metabolism provokes sulfur starvation, which can be growth limiting. Recent data indicate that sulfur deficiency determines protein damage-related Cr toxicity, due to mRNA mistranslation caused by Cr-induced S limitation. Sulfur deprivation could contribute to additional aspects of Cr toxicity, including oxidative DNA damage and Cr related disease.