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1
Vicente, C. P., P. Zancan, L. L. Peixoto, R. Alves-Sá, F. S. Araújo, P. A. S. Mourão, and M. S. G. Pavão. "Unbalanced Effects of Dermatan Sulfates with Different Sulfation Patterns on Coagulation, Thrombosis and Bleeding." Thrombosis and Haemostasis 86, no. 11 (2001): 1215–20. http://dx.doi.org/10.1055/s-0037-1616054.
Анотація:
SummaryWe compared the anticoagulant, antithrombotic and bleeding effects of highly sulfated dermatan sulfates from invertebrates and their mammalian counterpart. An invertebrate dermatan sulfate containing 2-O-sulfated α-L-iduronic acid and 4-O-sulfated N-acetyl-β-D-galactosamine residues is a potent anticoagulant due to a high heparin cofactor II activity. It inhibits thrombin due to the formation of a covalent complex with heparin cofactor II, as in the case of mammalian dermatan sulfate, but the effect occurs at lower concentrations for the invertebrate polysaccharide. Surprisingly, the invertebrate dermatan sulfate has a lower potency to prevent thrombus formation on an experimental model and a lower bleeding effect in rats than the mammalian dermatan sulfate. In contrast, another invertebrate dermatan sulfate, also enriched in 2-O-sulfated α-L-iduronic acid, but in this case sulfated at O-6 position of the N-acetyl-β-D-galactosamine units, has no in vitro or in vivo anticoagulant activity, does not prevent thrombus formation but shows a bleeding effect similar to the mammalian glycosaminoglycan. Overall, these results demonstrate unbalanced effects of dermatan sulfates with different sulfation patterns on coagulation, thrombosis and bleeding, and raise interesting questions concerning the relationship among these three biological actions of sulfated polysaccharides.
2
Chambers, W. H., and T. N. Oeltmann. "The effects of hexose 6-O-sulfate esters on human natural killer cell lytic function." Journal of Immunology 137, no. 5 (September 1, 1986): 1469–74. http://dx.doi.org/10.4049/jimmunol.137.5.1469.
Анотація:
Abstract Natural cell-mediated cytotoxicity (NCMC) is inhibited by some neutral hexoses and hexose phosphates at 25 to 100 mM concentrations. In this study we describe the effects of hexose 6-O-sulfate esters on NCMC against K-562 target cells. Mannose 6-sulfate, galactose 6-sulfate, N-acetylglucosamine 6-sulfate, and N-acetylgalactosamine 6-sulfate inhibit NCMC in a dose-dependent manner at concentrations of 10 mM and below. Inhibitory effects of mannose 6-sulfate and galactose 6-sulfate were evident at concentrations as low as 1.25 mM. The neutral forms of these sugars, glucose and glucose 6-sulfate, did not inhibit NCMC over this range of concentrations. Comparison of the inhibitory effects of sulfated and phosphorylated forms of mannose and galactose indicated that the sulfated forms are much more potent inhibitors. Formation of effector cell:target cell conjugates was unaffected by the presence of sugar sulfates. Calcium pulse experiments demonstrated that inhibitory effects of sugar sulfates were exerted after the Ca++-dependent triggering step in the NK lytic process. Kinetic studies showed that addition of sugars as long as 60 min after initiation of cultures yielded potent inhibitory effects. Sugar sulfates were not toxic for effector cell populations and effectors were not refractory for lytic function after removal of sugars. Sugar sulfates were inhibitory against multiple tumor types in both human and murine NK lytic assays. These results suggest that the sugar sulfates inhibit NK cells at a postconjugation, posttriggering step involving lectin-like receptors or lectin-like molecules.
3
Brandan, E., M. Maldonado, J. Garrido, and N. C. Inestrosa. "Anchorage of collagen-tailed acetylcholinesterase to the extracellular matrix is mediated by heparan sulfate proteoglycans." Journal of Cell Biology 101, no. 3 (September 1, 1985): 985–92. http://dx.doi.org/10.1083/jcb.101.3.985.
Анотація:
Heparan sulfate and heparin, two sulfated glycosaminoglycans (GAGs), extracted collagen-tailed acetylcholinesterase (AChE) from the extracellular matrix (ECM) of the electric organ of Discopyge tschudii. The effect of heparan sulfate and heparin was abolished by protamine; other GAGs could not extract the esterase. The solubilization of the asymmetric AChE apparently occurs through the formation of a soluble AChE-GAG complex of 30S. Heparitinase treatment but not chondroitinase ABC treatment of the ECM released asymmetric AChE forms. This provides direct evidence for the vivo interaction between asymmetric AChE and heparan sulfate residues of the ECM. Biochemical analysis of the electric organ ECM showed that sulfated GAGs bound to proteoglycans account for 5% of the total basal lamina. Approximately 20% of the total GAGs were susceptible to heparitinase or nitrous acid oxidation which degrades specifically heparan sulfates, and approximately 80% were susceptible to digestion with chondroitinase ABC, which degrades chondroitin-4 and -6 sulfates and dermatan sulfate. Our experiments provide evidence that asymmetric AChE and carbohydrate components of proteoglycans are associated in the ECM; they also indicate that a heparan sulfate proteoglycan is involved in the anchorage of the collagen-tailed AChE to the synaptic basal lamina.
4
Hobkirk, R., and Catherine A. Cardy. "The in vitro formation of sulfates and glucuronides of estrogens by adult and fetal ovine tissues." Canadian Journal of Biochemistry and Cell Biology 63, no. 8 (August 1, 1985): 785–91. http://dx.doi.org/10.1139/o85-100.
Анотація:
Incubation of nanomolar concentrations of [3H]estrone with ovine liver slices from adult and fetal animals demonstrated, in particular, the production of estrogen sulfates together with smaller amounts of glucuronides, even although microsomal estrogen glucuronyltransferase (GT) and sulfatase activities were high, especially in adult tissue. [3H]Estriol was conjugated almost exclusively as sulfate under the same experimental conditions. Slices of maternal and fetal kidney medulla were also strikingly active in promoting estrogen sulfate production as were slices of fetal kidney cortex. Adult kidney cortex conjugated estrogen only in the glucuronide form. These data indicate the possibility that maternal and fetal liver and kidney might contribute to the high circulating level of estrone sulfate in the pregnant sheep. Through the use of [3H]estrone and [3H]estrone sulfate as substrates, it was possible to demonstrate that adult slices of kidney medulla possessed relatively low sulfatase, considerable sulfotransferase (ST), and virtually no GT activity, whereas cortex had high sulfatase, little or no ST, and low, though demonstrable, GT activity. The ST activity of kidney high-speed supernatants was stimulated by the presence of sulfhydryl groups, whereas that in liver was not. Enzymic reduction of estrone and (or) estrone sulfate by liver and kidney slices indicated that, in the former, 17α-reduction prevailed and, in the latter with the exception of the maternal medulla, 17β-reduction was the main pathway, particularly in the fetus.
5
St. John, Thomas W. "Geotechnical characterization of sulfur species in UK Jurassic mudrocks." Quarterly Journal of Engineering Geology and Hydrogeology 53, no. 4 (February 26, 2020): 598–608. http://dx.doi.org/10.1144/qjegh2019-148.
Анотація:
Weathering of pyritic mudrocks results in the oxidation of sulfides and generation of sulfates in concentrations potentially hazardous to civil engineering works. Geochemical and petrographic analyses undertaken on samples from sites underlain by the Kimmeridge Clay Formation and Oxford Clay Formation proved three distinct zones: an upper sulfur-leached zone, an intermediate weathered zone with sulfate-rich horizons and a lower relatively unweathered zone of low-sulfate, high-sulfide material. It was found that water-soluble sulfate and total potential sulfate may vary by up to 1500 mg SO42− l−1 and 8% SO42− respectively, over a depth interval of only 0.2 m. A targeted sampling strategy and ground aggressivity assessment approach can be applied to these formations based upon the sulfur species zones identified.
6
PAVÃO, MAURO S. G. "Structure and anticoagulant properties of sulfated glycosaminoglycans from primitive Chordates." Anais da Academia Brasileira de Ciências 74, no. 1 (March 2002): 105–12. http://dx.doi.org/10.1590/s0001-37652002000100007.
Анотація:
Dermatan sulfates and heparin, similar to the mammalian glycosaminoglycans, but with differences in the degree and position of sulfation were previously isolated from the body of the ascidian Styela plicata and Ascidia nigra. These differences produce profound effects on their anticoagulant properties. S. plicata dermatan sulfate composed by 2-O-sulfatedalpha-L-iduronic acid and 4-O-sulfated N-acetyl-beta-D-galactosamine residues is a potent anticoagulant due to a high heparin cofactor II activity. Surprisingly, it has a lower potency to prevent thrombus formation on an experimental model and a lower bleeding effect in rats than the mammalian dermatan sulfate. In contrast, A. nigra dermatan sulfate, also enriched in 2-O-sulfated alpha-L-iduronic acid, but in this case sulfated at O-6 of the N-acetyl-beta-D-galactosamine units, has no in vitro or in vivo anticoagulant activity, does not prevent thrombus formation but shows a bleeding effect similar to the mammalian glycosaminoglycan. Ascidian heparin, composed by 2-O-sulfated alpha-L-iduronic acid, N- and 6-O-sulfated glucosamine (75%) and alpha-L-iduronic acid, N- and 6-O-sulfated glucosamine (25%) disaccharide units has an anticoagulant activity 10 times lower than the mammalian heparin, is about 20 times less potent in the inhibition of thrombin by antithrombin, but has the same heparin cofactor II activity as mammalian heparin.
7
Li, L., Z. M. Chen, Y. H. Zhang, T. Zhu, J. L. Li, and J. Ding. "Kinetics and mechanism of heterogeneous oxidation of sulfur dioxide by ozone on surface of calcium carbonate." Atmospheric Chemistry and Physics Discussions 6, no. 1 (January 17, 2006): 579–613. http://dx.doi.org/10.5194/acpd-6-579-2006.
Анотація:
Abstract. Sulfate particles play a key role in the air quality and the global climate, but the heterogeneous formation mechanism of sulfates on surfaces of atmospheric particles is not well established. Carbonates, which act as a reactive component in mineral dust due to their special chemical properties, may contribute significantly to the sulfate formation by heterogeneous processes. This paper presents a study on the oxidation of SO2 by O3 on CaCO3 particles. Using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), the formation of sulfite and sulfate on the surface was identified, and the roles of O3 and water in oxidation processes were determined. The results showed that in the presence of O3, SO2 can be oxidized to sulfate on the surface of CaCO3 particles. The reaction is first order in SO2 and zero order in O3. The reactive uptake coefficient for SO2 oxidation by O3 was determined to be (1.4±0.3)×10−7 using the BET area as the reactive area and (7.7±1.6)×10−4 using the geometric area. A two-stage mechanism that involves adsorption of SO2 followed by O3 oxidation is proposed and the adsorption of SO2 on the CaCO3 surface is the rate-determining step. The proposed mechanism can well explain the experiment results. The atmospheric implications were explored based on a box model calculation. It was found that the heterogeneous reaction might be an important pathway for sulfate formation in the atmosphere.
8
Attal, A., M. Brigodiot, P. Camacho, and J. Manem. "Biological Mechanisms of H2S Formation in Sewer Pipes." Water Science and Technology 26, no. 3-4 (August 1, 1992): 907–14. http://dx.doi.org/10.2166/wst.1992.0471.
Анотація:
The purpose of this study is to gain a better understanding of the biological phenomena involved in the production of hydrogen sulfide in urban wastewater (UWW) systems. It is found that the UWW itself naturally possesses the biomass needed to consume the sulfates. These heterotrophic sulfate-reducing bacteria populations, though immediately active in strict anaerobic conditions, are present only in very low concentrations in the UWW. A concentration of them was studied within the pressure pipes, in the form of deposits, and this justifies the high concentrations of sulfides measured in certain wastewater networks. There are two reasons why the ferrous sulfate used as a treatment in any wastewater networks should not cause the production of additional sulfides. Firstly, the sulfate consumption kinetics are always too slow, relative to the residence time of the water in the pipe, for all of the sulfates to be consumed anyway. Secondly, the amount of assimilable carbon, soluble carbon, and carbon from suspended solid (SS) hydrolysis is insufficient.
9
Li, L., Z. M. Chen, Y. H. Zhang, T. Zhu, J. L. Li, and J. Ding. "Kinetics and mechanism of heterogeneous oxidation of sulfur dioxide by ozone on surface of calcium carbonate." Atmospheric Chemistry and Physics 6, no. 9 (June 29, 2006): 2453–64. http://dx.doi.org/10.5194/acp-6-2453-2006.
Анотація:
Abstract. Sulfate particles play a key role in the air quality and the global climate, but the heterogeneous formation mechanism of sulfates on surfaces of atmospheric particles is not well established. Carbonates, which act as a reactive component in mineral dust due to their special chemical properties, may contribute significantly to the sulfate formation by heterogeneous processes. This paper presents a study on the oxidation of SO2 by O3 on CaCO3 particles. Using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), the formation of sulfite and sulfate on the surface was identified, and the roles of O3 and water in oxidation processes were determined. The results showed that in the presence of O3, SO2can be oxidized to sulfate on the surface of CaCO3 particles. The reaction is first order in SO2 and zero order in O3. The reactive uptake coefficient for SO2 [(0.6–9.8)×1014 molecule cm-3] oxidation by O3 [(1.2–12)×1014 molecule cm-3] was determined to be (1.4±0.3)×10-7 using the BET area as the reactive area and (7.7±1.6)×10-4 using the geometric area. A two-stage mechanism that involves adsorption of SO2 followed by O3 oxidation is proposed and the adsorption of SO2 on the CaCO3 surface is the rate-determining step. The proposed mechanism can well explain the experiment results. The atmospheric implications were explored based on a box model calculation. It was found that the heterogeneous reaction might be an important pathway for sulfate formation in the atmosphere.
10
Sheng, Juzheng, Renpeng Liu, Yongmei Xu, and Jian Liu. "The Dominating Role of N-Deacetylase/N-Sulfotransferase 1 in Forming Domain Structures in Heparan Sulfate." Journal of Biological Chemistry 286, no. 22 (March 28, 2011): 19768–76. http://dx.doi.org/10.1074/jbc.m111.224311.
Анотація:
Heparan sulfate (HS) is a highly sulfated polysaccharide participated in essential physiological functions from regulating cell growth to blood coagulation. HS contains sulfated domains known as N-S domains and low sulfate domains known as N-Ac domains. The distribution of the domain structures is likely governed by the action of glucosaminyl N-deacetylase/N-sulfotransferase (NDST). Here, we sought to determine the substrate specificity of NDST using model substrates and recombinant NDST protein. We discovered that NDST-1 carries out the modification in a highly ordered fashion. The enzyme sulfates the substrate from the nonreducing end toward the reducing end consecutively, leading to the product with a cluster of N-sulfo glucosamine residues. Furthermore, a preexisting N-sulfo glucosamine residue prevents the action of NDST-1 at the residues immediately located at the nonreducing end, allowing the formation of an N-Ac domain. Our results provide the long sought evidence for understanding the formation of sulfated versus nonsulfated domains in the HS isolated from cells and tissues. The study demonstrates the regulating role of NDST-1 in mapping the sulfation patterns of HS.
11
Zvir, G. І., O. М. Moroz та S. O. Hnatush. "Dissimilatory sulfate reduction in bacteria Desulfovibrio desulfuricans ІМV К-6 upon influence of Uragan and Raundup herbicides". Visnyk of Dnipropetrovsk University. Biology, medicine 6, № 1 (26 лютого 2015): 40–44. http://dx.doi.org/10.15421/021508.
Анотація:
Objects of the study were sulfate-reducing bacteria Desulfovibrio desulfuricans ІМV К-6, isolated from Yavorivske lakе. This strain is kept in the collection of microorganisms at the Department of Microbiology of Ivan Franko National University. Bacteria were grown in the Kravtsov-Sorokin’s liquid medium with the following composition (g/l): Na2SO4 × 10H2O – 0.5, NaH2PO4 – 0.3, K2HPO4 – 0.5, (NH4)2SO4 – 0.2, MgSO4 × 7H2O – 0.1, C3H5O3Na – 2.0. The bacteria were grown for 10 days at 30 °C under anaerobic conditions. In order to study the sensitivity of the sulfate reducing bacteria to action of Uragan and Raundup herbicides, the cells of D. desulfuricans ІМV К-6 were grown at the concentrations of herbicides as follows: 0,28 mМ, 2,8 mМ (concentration recommended for use) and 5,6 mM. Biomass was determined by photometric method. Concentration of hydrogen sulfide in the culture medium was determined by photo-colorimetric method. Concentration of sulfate-ions in the medium was determined by turbidimetric method. Capacity of sulfate reducing bacteria D. desulfuricans ІМV K-6 to grow, reducing sulfates to hydrogen sulfide upon influence of Uragan and Raundup herbicides was studied. Accumulation of bacterial biomass in the control and upon influence of herbicides was the highest on the fourth-sixth day of cultivation, and after that the stationary growth phase began. It was shown that sulfate reducing bacteria upon influence of herbicides grew more intensively compared with the control. It was discovered that the level of biomass changed depending on the increasing concentration of Uragan or Raundup herbicides in the medium. Sulfate reducing bacteria D. desulfuricans ІМV K-6 could reduce sulfates to hydrogen sulfide in the presence of sulfates and organic compounds in the medium (dissimilatory sulfate reduction). Stimulatory influence of Uragan and Raundup on the dissimilatory sulfate reduction process of D. desulfuricans ІМВ К-6 has been discovered. The formation of hydrogen sulfide correlates with the usage of sulfatе ions. The capacity of sulfate reducing bacteria D. desulfuricans ІМV K-6 to grow, reducing sulfate ions to hydrogen sulfide upon influence of Uragan and Raundup may be caused by presence of inert components (sulfates) in these herbicides that can be used by microorganisms as electron acceptors during sulfate respiration.
12
Chinchón-Payá, S., A. Aguado, H. W. Nugterenc, and S. Chinchón. "External sulfate attack in dam concretes with thaumasite formation." Materiales de Construcción 65, no. 317 (January 26, 2015): e042. http://dx.doi.org/10.3989/mc.2015.10513.
13
Taherdangkoo, Reza, Miaomiao Tian, Ali Sadighi, Tao Meng, Huichen Yang, and Christoph Butscher. "Experimental Data on Solubility of the Two Calcium Sulfates Gypsum and Anhydrite in Aqueous Solutions." Data 7, no. 10 (October 16, 2022): 140. http://dx.doi.org/10.3390/data7100140.
Анотація:
Calcium sulfate exists in three forms, namely dihydrate or gypsum (CaSO4·2H2O), anhydrite (CaSO4), and hemihydrate or bassanite (CaSO4·0.5H2O) depending on temperature, pressure, pH, and formation conditions. The formation of calcium sulfates occurs widely in nature and in many engineering settings. Herein, a dataset containing the experimental solubility data of calcium sulfate minerals, i.e., gypsum and anhydrite, in aqueous solutions is presented. The compiled dataset contains calcium sulfates solubility values extracted from 42 papers published between 1906 and 2019. The dataset can be used for various scientific and engineering purposes such as environmental applications (e.g., gas treatment, wastewater treatment, and chemical disposal), geotechnical applications (e.g., clay-sulfate rock swelling), separation processes (e.g., crystallization, extractive distillation, and seawater desalination), and electrochemical processes (e.g., corrosion and electrolysis).
14
Yang, Wangjin, Jiawei Ma, Hongxing Yang, Fu Li, and Chong Han. "Photoenhanced sulfate formation by the heterogeneous uptake of SO2 on non-photoactive mineral dust." Atmospheric Chemistry and Physics 24, no. 11 (June 12, 2024): 6757–68. http://dx.doi.org/10.5194/acp-24-6757-2024.
Анотація:
Abstract. Heterogeneous uptake of SO2 on mineral dust is a predominant formation pathway of sulfates, whereas the contribution of photo-induced SO2 oxidation to sulfates on the dust interfaces still remains unclear. Here, we investigated heterogeneous photochemical reactions of SO2 on five mineral oxides (SiO2, kaolinite, Al2O3, MgO, and CaO) without photocatalytic activity. Light enhanced the uptake of SO2, and its enhancement effects negatively depended on the basicity of mineral oxides. The initial uptake coefficient (γ0,BET) and the steady-state uptake coefficient (γs,BET) of SO2 positively relied on light intensity, relative humidity (RH), and O2 content, while they exhibited a negative relationship with the initial SO2 concentration. Rapid sulfate formation during photo-induced heterogeneous reactions of SO2 with all mineral oxides was confirmed to be ubiquitous, and H2O and O2 played key roles in the conversion of SO2 to sulfates. In particular, triplet states of SO2 (3SO2) were suggested to be the trigger for photochemical sulfate formation. Atmospheric implications supported a potential contribution of interfacial SO2 photochemistry on non-photoactive mineral dust to atmospheric sulfate sources.
15
Kurmangalieva, Anna I., Lyubov' A. Anikanova, Ol'ga V. Volkova, Alexandr I. Kudyakov, Yurij S. Sarkisov, and Yurij A. Abzaev. "ACTIVATION OF HARDENING PROCESSES OF FLUOROGYPSUM COMPOSITIONS BY CHEMICAL ADDITIVES OF SODIUM SALTS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, no. 8 (June 24, 2020): 73–80. http://dx.doi.org/10.6060/ivkkt.20206308.6137.
Анотація:
The article is devoted to modifications of fluorogypsum compositions by chemical additives of sodium salts in the form of sulfate, sulfite and sodium sulfide, as well as their combined effect on the kinetics of structure formation processes. Technological, ecological and technical aspects of utilization of fluorogypsum compositions activated by additives were investigated. Experiments have shown that an up to 3% increase in the amount of sodium sulfite additive leads to an increase in the compressive strength of samples at early stages of hardening (up to 14 days), whereas utilization of sodium sulfate additive forms a crystallization structure at later stages. Therefore, it is rational to combine sulfate and sodium sulfite additives in an amount not exceeding 3% of the binder’s weight. The binder hardening structure formation with sodium sulfide addition at early stages results in production of additional structure-forming substances such as calcium sulfide. The mechanism of differentiated application of individual sulfate and sodium sulfite additives allowed to suggest that combined sulfate and sulfite additives utilization seems to be the most rational decision, due to the fact that it is not a mere individual additives’ combination, but a buffer mixture, which means that the mechanism of such mixtures influence will be subject to the buffer action. The system will maintain a strictly defined pH range constancy, which determines stability of new growths, forming the hardening structure. However, using sodium sulfide as an additive and studying its impact on fluoroanhydrate compositions structure formation in both individual and combined with sodium sulfite and sodium sulfate forms appears to be as much reasonable. The combined Na2SO3-Na2SO4 additive activates hardening processes both at early and late stages. At the same time, columnar structures growing from the center to the periphery are formed, as indicated by electron-microscopic studies. Their growth stems from concentration gradient of SO42-- and SO32-- ions, which is in complete agreement with the other research data and is typical for both metal melts and cement systems solidification process.
16
NAHAR, Syeda Jabun, Syed M. HAQUE, and Shimasaki KAZUHIKO. "Application of Chondroitin Sulfate on Organogenesis of Two Cymbidium spp. under Different Sources of Lights." Notulae Scientia Biologicae 8, no. 2 (June 17, 2016): 156–60. http://dx.doi.org/10.15835/nsb829801.
Анотація:
The aim of this study was to present chondroitin sulfate as a plant growth regulator and to give an overview about light effects on PLBs (protocorm like bodies) culture of Cymbidium dayanum and Cymbidium finlaysonianum cultured in vitro. Chondroitin sulfate is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars N-acetylgalactosamine and glucuronic acid. It is widely used as a material for food ingredients, cosmetics and medicine. PLBs were cultured on modified MS medium containing different concentration of chondroitin sulfate (0, 0.1, 1 and 10 mg/l), under four sources of lights: conventional white fluorescent tube, red LED, green LED and blue LED. In C. dayanum, 100% PLBs formation rate was observed at 0.1 mg/l chondroitin sulfate with modified MS medium under green LED and 1 mg/l chondroitin sulfate under blue LED; the maximum shoots and roots formation were observed under green LEDs (93% and 80% respectively) when media contained 0.1 mg/l chondroitin sulfate. In C. finlaysonianum, every concentrations of chondroitin sulfate enhanced the growth rate of PLBs when compared to control treatment, under all four sources of lights. The highest values were recorded with 0.1 mg/l chondroitin sulfate which induced 100% PLBs formation under blue LED, while 10 mg/l chondroitin sulfate had induced 100% PLBs formation under green LED. The highest percentage of shoots (73%) was initiated in the medium containing 10 mg/l chondroitin sulfate under green LED. Plant development was strongly influenced by the light quality and plant growth regulator functions as chemical messengers for intercellular communication of plant. The results demonstrated that low concentrations of chondroitin sulfate could promote PLBs, shoots and roots formation of Cymbidium spp. under green and blue LED.
17
Farzan, Michael, Christine E. Schnitzler, Natalya Vasilieva, Doris Leung, Jens Kuhn, Craig Gerard, Norma P. Gerard, and Hyeryun Choe. "Sulfated Tyrosines Contribute to the Formation of the C5a Docking Site of the Human C5a Anaphylatoxin Receptor." Journal of Experimental Medicine 193, no. 9 (May 7, 2001): 1059–66. http://dx.doi.org/10.1084/jem.193.9.1059.
Анотація:
The complement anaphylatoxin C5a and its seven-transmembrane segment (7TMS) receptor play an important role in host defense and in a number of inflammation-associated pathologies. The NH2-terminal domain of the C5a receptor (C5aR/CD88) contributes substantially to its ability to bind C5a. Here we show that the tyrosines at positions 11 and 14 of the C5aR are posttranslationally modified by the addition of sulfate groups. The sulfate moieties of each of these tyrosines are critical to the ability of the C5aR to bind C5a and to mobilize calcium. A C5aR variant lacking these sulfate moieties efficiently mobilized calcium in response to a small peptide agonist, but not to C5a, consistent with a two-site model of ligand association in which the tyrosine-sulfated region of the C5aR mediates the initial docking interaction. A peptide based on the NH2 terminus of the C5aR and sulfated at these two tyrosines, but not its unsulfated analogue or a doubly sulfated control peptide, partially inhibited C5a association with its receptor. These observations clarify structural and mutagenic studies of the C5a/C5aR association and suggest that related 7TMS receptors are also modified by functionally important sulfate groups on their NH2-terminal tyrosines.
18
Chu, Biwu, Yali Wang, Weiwei Yang, Jinzhu Ma, Qingxin Ma, Peng Zhang, Yongchun Liu, and Hong He. "Effects of NO<sub>2</sub> and C<sub>3</sub>H<sub>6</sub> on the heterogeneous oxidation of SO<sub>2</sub> on TiO<sub>2</sub> in the presence or absence of UV–Vis irradiation." Atmospheric Chemistry and Physics 19, no. 23 (December 9, 2019): 14777–90. http://dx.doi.org/10.5194/acp-19-14777-2019.
Анотація:
Abstract. The heterogeneous reactions of SO2 in the presence of NO2 and C3H6 on TiO2 were investigated with the aid of in situ diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) under dark conditions or with UV–Vis irradiation. Sulfate formation with or without the coexistence of NO2 and/or C3H6 was analyzed with ion chromatography (IC). Under dark conditions, SO2 reacting alone resulted in sulfite formation on TiO2, while the presence of parts per billion (ppb) levels of NO2 promoted the oxidation of SO2 to sulfate. The presence of C3H6 had little effect on sulfate formation in the heterogeneous reaction of SO2 but suppressed sulfate formation in the heterogeneous reaction of SO2 and NO2. UV–Vis irradiation could significantly enhance the heterogeneous oxidation of SO2 on TiO2, leading to copious generation of sulfate, while the coexistence of NO2 and/or C3H6 significantly suppressed sulfate formation in experiments with UV–Vis lights. Step-by-step exposure experiments indicated that C3H6 mainly competes for reactive oxygen species (ROS), while NO2 competes with SO2 for both surface active sites and ROS. Meanwhile, the coexistence of NO2 with C3H6 further resulted in less sulfate formation compared to introducing either one of them separately to the SO2–TiO2 reaction system. The results of this study highlighted the complex heterogeneous reaction processes that take place due to the ubiquitous interactions between organic and inorganic species and the need to consider the influence of coexisting volatile organic compounds (VOCs) and other inorganic gases in the heterogeneous oxidation kinetics of SO2.
19
Borzenko, Svetlana. "Geochemical transformations of sulfur in salt lakes (Transbaikalia)." E3S Web of Conferences 411 (2023): 02009. http://dx.doi.org/10.1051/e3sconf/202341102009.
Анотація:
The water column in brackish and saline lakes hosts various forms of sulfur including sulfide (hydrosulfide), elemental, thiosulfate, and sulfate sulfur. The unequal distribution of these reduced sulfur species indicates the presence of two opposing processes - sulfate reduction and oxidation of newly formed hydrogen sulfide. The scale of these processes varies among lakes, resulting in differing proportions of reduced sulfur forms. The bacterial reduction of sulfate ions is confirmed by a significant separation of sulfur isotopes into sulfide and sulfate ions, with the lighter isotope accumulating in the former and heavier isotope in the latter. In most soda, chloride, brackish, and salt lakes, sulfate reduction is the principal process responsible for relatively low sulfate ion content. Additionally, the presence of an oxidizing environment and sulfides in host rocks provide additional sources for sulfates, leading to the formation of sulfate-type lakes. The formation of specific types and subtypes of brackish and salt lakes is determined by processes such as water evaporation, dissolution of aluminosilicates, sulfate reduction, and oxidation of sulfides. The dominance of these processes contributes to the geochemical diversity of lakes.
20
Thornton, Mark, Laura Barkley, Justin C. Mason, and Sunil Shaunak. "Anti-Kaposi’s Sarcoma and Antiangiogenic Activities of Sulfated Dextrins." Antimicrobial Agents and Chemotherapy 43, no. 10 (October 1, 1999): 2528–33. http://dx.doi.org/10.1128/aac.43.10.2528.
Анотація:
ABSTRACT Delivery of the sulfated polysaccharide dextrin 2-sulfate by the intraperitoneal route to the lymphatic circulation resulted in a clinically significant improvement in Kaposi’s sarcoma in three patients. Our in vitro studies show that although sulfated dextrins do not interfere with the growth of isolated human umbilical vein endothelial cells, they do inhibit the morphological differentiation of endothelial cells into tubes as well as reduce new vessel formation in a placental angiogenesis assay. The antiangiogenic effect of dextrin 6-sulfate is greater than that of dextrin 2-sulfate and is independent of their anti-human immunodeficiency virus type 1 activities.
21
Zarubica, Aleksandra, Branislav Jovic, Aleksandar Nikolic, Paula Putanov, and Goran Boskovic. "Temperature imposed textural and surface synergism affecting the isomerization activity of sulfated zirconia catalysts." Journal of the Serbian Chemical Society 74, no. 12 (2009): 1429–42. http://dx.doi.org/10.2298/jsc0912429z.
Анотація:
Using sulfuric acid as the sulfating agent, two catalyst series were obtained from hydroxide and nitrate precursor with a sulfate loading identical to commercial sulfated hydroxide, i.e., 4.2 mass%. After calcination at 500, 600 and 700?C, all nine samples had various contents of residual sulfates depending on the origin of the catalyst. Accordingly, their surface properties were different, which, together with various textural properties, govern the formation of the active phase and their catalytic activity in the n-hexane isomerization reaction. The dominant activity and yield of mainly mono-branched isomers were attained in reaction at 200?C with a commercially sulfated zirconia catalyst calcined at 500?C. Among the SZ catalyst series synthesized from hydroxide and nitrate, the second according to its activity profile was similar to that of the commercially sulfated one, while samples originating from hydroxide showed some activity only after calcination at 600?C. This is due to the poorer textural properties of the hydroxide series, necessitating a higher calcination temperature in order to promote the simultaneous decomposition of S-containing species and their re-adsorption into the zirconia matrix following interaction and active phase formation. It seems that the tetragonal zirconia phase was not responsible for the catalytic activity but a synergistic effect of the textural properties of the samples and the sulfate loadings, which determine different acid strengths on the catalyst surface.
22
Baustian, K. J., M. E. Wise, and M. A. Tolbert. "Depositional ice nucleation on solid ammonium sulfate and glutaric acid particles." Atmospheric Chemistry and Physics 10, no. 5 (March 5, 2010): 2307–17. http://dx.doi.org/10.5194/acp-10-2307-2010.
Анотація:
Abstract. Heterogeneous ice nucleation on solid ammonium sulfate and glutaric acid particles was studied using optical microscopy and Raman spectroscopy. Optical microscopy was used to detect selective nucleation events as water vapor was slowly introduced into an environmental sample cell. Particles that nucleated ice were dried via sublimation and examined in detail using Raman spectroscopy. Depositional ice nucleation is highly selective and occurred preferentially on just a few ammonium sulfate and glutaric acid particles in each sample. For freezing temperatures between 214 K and 235 K an average ice saturation ratio of S = 1.10±0.07 for solid ammonium sulfate was observed. Over the same temperature range, S values observed for ice nucleation on glutaric acid particles increased from 1.2 at 235 K to 1.6 at 218 K. Experiments with externally mixed particles further show that ammonium sulfate is a more potent ice nucleus than glutaric acid. Our results suggest that heterogeneous nucleation on ammonium sulfate may be an important pathway for atmospheric ice nucleation and cirrus cloud formation when solid ammonium sulfate aerosol particles are available for ice formation. This pathway for ice formation may be particularly significant near the tropical tropopause region where sulfates are abundant and other species known to be good ice nuclei are depleted.
23
Baustian, K. J., M. E. Wise, and M. A. Tolbert. "Depositional ice nucleation on solid ammonium sulfate and glutaric acid particles." Atmospheric Chemistry and Physics Discussions 9, no. 5 (October 5, 2009): 20949–77. http://dx.doi.org/10.5194/acpd-9-20949-2009.
Анотація:
Abstract. Heterogeneous ice nucleation on solid ammonium sulfate and solid amorphous glutaric acid particles was studied using optical microscopy and Raman spectroscopy. Optical microscopy was used to detect selective nucleation events as water vapor was slowly introduced into an environmental sample cell. Particles that nucleated ice were dried via sublimation and examined in detail using Raman spectroscopy. Depositional ice nucleation occurred preferentially on just a few ammonium sulfate and glutaric acid particles in each sample. For freezing temperatures between 214 K and 235 K average ice saturation ratios of S=1.10±0.07 for solid ammonium sulfate and S=1.39±0.16 for solid amorphous glutaric acid particles were determined. Experiments with externally mixed particles further show that ammonium sulfate is a more potent ice nucleus that glutaric acid. Our results suggest that heterogeneous nucleation on ammonium sulfate may be an important pathway for atmospheric ice nucleation and cirrus cloud formation when solid aerosol particles are available for ice formation. This pathway for ice formation may be particularly significant near the tropopause region where sulfates are abundant and other species known to be good ice nuclei are depleted.
24
Semenyuk, Pavel, Lidia Kurochkina, Kseniya Barinova, and Vladimir Muronetz. "Alpha-Synuclein Amyloid Aggregation Is Inhibited by Sulfated Aromatic Polymers and Pyridinium Polycation." Polymers 12, no. 3 (February 28, 2020): 517. http://dx.doi.org/10.3390/polym12030517.
Анотація:
The effect of a range of synthetic charged polymers on alpha-synuclein aggregation and amyloid formation was tested. Sulfated aromatic polymers, poly(styrene sulfonate) and poly(anethole sulfonate), have been found to suppress the fibril formation. In this case, small soluble complexes, which do not bind with thioflavin T, have been formed in contrast to the large stick-type fibrils of free alpha-synuclein. Sulfated polysaccharide (dextran sulfate), as well as sulfated vinylic polymer (poly(vinyl sulfate)) and polycarboxylate (poly(methacrylic acid)), enhanced amyloid aggregation. Conversely, pyridinium polycation, poly(N-ethylvinylpyridinium), switched the mechanism of alpha-synuclein aggregation from amyloidogenic to amorphous, which resulted in the formation of large amorphous aggregates that do not bind with thioflavin T. The obtained results are relevant as a model of charged macromolecules influence on amyloidosis development in humans. In addition, these results may be helpful in searching for new approaches for synucleinopathies treatment with the use of natural polymers.
25
Sotiriadis, Konstantinos, and Michal Hlobil. "Prediction of Sulfate Attack Products in Portland-Limestone Cements: The Effect of Cation Type and Concentration." Solid State Phenomena 325 (October 11, 2021): 28–33. http://dx.doi.org/10.4028/www.scientific.net/ssp.325.28.
Анотація:
Portland-limestone cement materials are susceptible to sulfate attack at low temperature and high humidity, because such conditions facilitate the formation of thaumasite, detriment to the structural integrity of calcium silicate hydrates (C─S─H). In this work, the effect of the cation associated with sulfates, concentration of sulfate solution, and limestone content in cement, were thermodynamically simulated. MgSO4 solution is of higher risk, degrading extensively the structural integrity of C─S─H. Although this phase is partially preserved under the effect of Na2SO4 and K2SO4 solutions, extensive expansion and thaumasite formation occur. The sulfate content of the corrosive solution and the limestone content in cement are the factors mostly intensifying the attack caused by MgSO4 and Na2SO4/K2SO4 solutions, respectively.
26
Kr�mer, Michael, and Heribert Cypionka. "Sulfate formation via ATP sulfurylase in thiosulfate- and sulfite-disproportionating bacteria." Archives of Microbiology 151, no. 3 (February 1989): 232–37. http://dx.doi.org/10.1007/bf00413135.
27
Colman, Charlotte, David Bulteel, Sébastien Rémond, Zengfeng Zhao, and Luc Courard. "Valorization of Fine Recycled Aggregates Contaminated with Gypsum Residues: Characterization and Evaluation of the Risk for Secondary Ettringite Formation." Materials 13, no. 21 (October 30, 2020): 4866. http://dx.doi.org/10.3390/ma13214866.
Анотація:
Fine recycled aggregates (FRA) (0/4 mm) are up to now not valorized on a high enough level because of characteristics like an elevated water absorption, higher fines content, and the presence of contaminations. Leftover gypsum residues from the construction site can cause internal sulfate attack when FRA are incorporated into new structures. Concern about this deteriorating reaction plays an important role in the rejection of FRA. In this study, samples of FRA from different recycling centers were characterized and incorporated into mortars. They were then subjected to swelling tests in order to evaluate the development of sulfate attack. Reference materials with different amounts of sulfates were used as a comparison. Results showed a variable sulfate content in industrial FRA, depending heavily on the source of the materials. In all but one case, the total amounts surpassed the acceptable sulfate contents specified in the European standard EN 206, meaning the FRA would be rejected for reuse in concrete. Nevertheless, swelling tests demonstrated that these contamination levels did not pose a risk for sulfate attack. These results indicated that the incorporation of FRA leads to acceptable mechanical performances and that the sulfate limit could be reviewed to be less strict.
28
Bednarchuk, Tamara J., Vasyl Kinzhybalo, and Adam Pietraszko. "Synthesis, structure and characterization of five new organically templated metal sulfates with 2-aminopyridinium." Acta Crystallographica Section C Structural Chemistry 72, no. 5 (April 21, 2016): 432–41. http://dx.doi.org/10.1107/s2053229616006458.
Анотація:
The chemistry of organically templated metal sulfates has attracted interest from the materials science community and the development of synthetic strategies for the preparation of organic–inorganic hybrid materials with novel structures and special properties is of current interest. Sulfur–oxygen–metal linkages provide the possibility of using sulfate tetrahedra as building units to form new solid-state materials. A series of novel organically templated metal sulfates of 2-aminopyridinium (2ap) with aluminium(III), cobalt(II), magnesium(II), nickel(II) and zinc(II) were obtained from the respective aqueous solutions and studied by single-crystal X-ray diffraction. The compounds crystallize in centrosymmetric triclinic unit cells in three structure types: type 1 for 2-aminopyridinium hexaaquaaluminium(III) bis(sulfate) tetrahydrate, (C5H7N2)[Al(H2O)6](SO4)2·4H2O, (I); type 2 for bis(2-aminopyridinium) tris[hexaaquacobalt(II)] tetrakis(sulfate) dihydrate, (C5H7N2)2[Co(H2O)6]3(SO4)4·2H2O, (II), and bis(2-aminopyridinium) tris[hexaaquamagnesium(II)] tetrakis(sulfate) dihydrate, (C5H7N2)2[Mg(H2O)6]3(SO4)4·2H2O, (III); and type 3 for bis(2-aminopyridinium) hexaaquanickel(II) bis(sulfate), (C5H7N2)2[Ni(H2O)6](SO4)2, (IV), and bis(2-aminopyridinium) hexaaquazinc(II) bis(sulfate), (C5H7N2)2[Zn(H2O)6](SO4)2, (V). The templating role of the 2ap cation in all of the reported crystalline substances is governed by the formation of characteristic charge-assisted hydrogen-bonded pairs with sulfate anions and the presence of π–π interactions between the cations. Additionally, both coordinated and uncoordinated water molecules are involved in hydrogen-bond formation. As a consequence, extensive three-dimensional hydrogen-bonding patterns are formed in the reported crystal structures.
29
Fang, Yanhua, Chunxiang Ye, Junxia Wang, Yusheng Wu, Min Hu, Weili Lin, Fanfan Xu, and Tong Zhu. "Relative humidity and O<sub>3</sub> concentration as two prerequisites for sulfate formation." Atmospheric Chemistry and Physics 19, no. 19 (October 2, 2019): 12295–307. http://dx.doi.org/10.5194/acp-19-12295-2019.
Анотація:
Abstract. Sulfate formation mechanisms have been discussed extensively but are still disputed. In this work, a year-long particulate matter (PM2.5) sampling campaign was conducted together with measurements of gaseous pollutant concentrations and meteorological parameters in Beijing, China, from March 2012 to February 2013. The sulfur oxidation ratio (SOR), an indicator of secondary sulfate formation, displayed a clear summer peak and winter valley, even though no obvious seasonal variations in sulfate mass concentration were observed. A rapid rise in the SOR was found at a relative humidity (RH) threshold of ∼45 % or an O3 concentration threshold of ∼35 ppb, allowing us to first introduce the idea that RH and O3 concentrations are two prerequisites for rapid sulfate formation via multiphase reactions. In the case of the RH threshold, this is consistent with current understanding of the multiphase formation of sulfate, since it relates to the semisolid-to-liquid phase transition of atmospheric aerosols. Correlation analysis between SOR and aerosol water content (AWC) further backed this up. In the case of the O3 concentration threshold, this is consistent with the consumption of liquid oxidants in multiphase sulfate formation. The thresholds introduced here lead us to a better understanding of the sulfate formation mechanisms and sulfate formation variations. H2O2 might be the major oxidant of sulfate formation, since another liquid-phase oxidant, O3, has previously been shown to be unimportant. The seasonal variations in sulfate formation could be accounted for by variations in the RH and O3 prerequisites. For example, over the year-long study, the fastest SO2-to-sulfate conversion occurred in summer, which was associated with the highest values of O3 (and also H2O2) concentration and RH. The SOR also displayed variations with pollution levels; i.e. the SOR increased with PM2.5 in all seasons. Such variations were primarily associated with a transition from the slow gas-phase formation of sulfate to rapid multiphase reactions, since RH increased higher than its prerequisite value of around 45 % as pollution evolved. In addition, the self-catalytic nature of sulfate formation (i.e. the formation of hydrophilic sulfate aerosols under high RH conditions results in an increase in aerosol water content, which results in greater particle volume for further multiphase sulfate formation) also contributed to variations among the pollution scenarios.
30
Troshina, M. A. "ABOUT COMPLEX FORMATION IN THE “CHROMIC SULFATE (III) – ALUMINUM SULFATE – TITANYL SULFATE – WATER” SYSTEM." Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta, no. 1 (2017): 23–29. http://dx.doi.org/10.18323/2073-5073-2017-1-23-29.
31
McDonald, Robbie G., Jian Li, and Peter J. Austin. "High Temperature Pressure Oxidation of a Low-Grade Nickel Sulfide Concentrate with Control of the Residue Composition." Minerals 10, no. 3 (March 9, 2020): 249. http://dx.doi.org/10.3390/min10030249.
Анотація:
High temperature pressure oxidation of a low-grade nickel concentrate was examined to demonstrate the potential benefits and shortcomings of this approach. The high iron sulfide content ensured that acid generation was much greater than for higher grade concentrates. This results in the formation of basic iron sulfate phases and a significant amount of sulfuric acid. Kinetic sampling during pressure oxidation tests also demonstrated the transformation of sulfide minerals, including the oxidative transformations of pentlandite to violarite and then to vaesite, the latter phase not previously noted in studies of this kind. Finally, addition of a divalent metal sulfate buffer, here magnesium sulfate, mitigates the formation of basic iron sulfates but with greater generation of sulfuric acid in the leach liquor. Under the conditions employed in this study, this acid could be employed to leach other nickel-containing materials such as nickel laterites.
32
Lim, Yong Bin, Hwajin Kim, Jin Young Kim, and Barbara J. Turpin. "Photochemical organonitrate formation in wet aerosols." Atmospheric Chemistry and Physics 16, no. 19 (October 11, 2016): 12631–47. http://dx.doi.org/10.5194/acp-16-12631-2016.
Анотація:
Abstract. Water is the most abundant component of atmospheric fine aerosol. However, despite rapid progress, multiphase chemistry involving wet aerosols is still poorly understood. In this work, we report results from smog chamber photooxidation of glyoxal- and OH-containing ammonium sulfate or sulfuric acid particles in the presence of NOx and O3 at high and low relative humidity. Particles were analyzed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). During the 3 h irradiation, OH oxidation products of glyoxal that are also produced in dilute aqueous solutions (e.g., oxalic acids and tartaric acids) were formed in both ammonium sulfate (AS) aerosols and sulfuric acid (SA) aerosols. However, the major products were organonitrogens (CHNO), organosulfates (CHOS), and organonitrogen sulfates (CHNOS). These were also the dominant products formed in the dark chamber, indicating non-radical formation. In the humid chamber (> 70 % relative humidity, RH), two main products for both AS and SA aerosols were organonitrates, which appeared at m ∕ z− 147 and 226. They were formed in the aqueous phase via non-radical reactions of glyoxal and nitric acid, and their formation was enhanced by photochemistry because of the photochemical formation of nitric acid via reactions of peroxy radicals, NOx and OH during the irradiation.
33
Lam, Hoi Ki, Kai Chung Kwong, Hon Yin Poon, James F. Davies, Zhenfa Zhang, Avram Gold, Jason D. Surratt, and Man Nin Chan. "Heterogeneous OH oxidation of isoprene-epoxydiol-derived organosulfates: kinetics, chemistry and formation of inorganic sulfate." Atmospheric Chemistry and Physics 19, no. 4 (February 26, 2019): 2433–40. http://dx.doi.org/10.5194/acp-19-2433-2019.
Анотація:
Abstract. Acid-catalyzed multiphase chemistry of epoxydiols formed from isoprene oxidation yields the most abundant organosulfates (i.e., methyltetrol sulfates) detected in atmospheric fine aerosols in the boundary layer. This potentially determines the physicochemical properties of fine aerosols in isoprene-rich regions. However, chemical stability of these organosulfates remains unclear. As a result, we investigate the heterogeneous oxidation of aerosols consisting of potassium 3-methyltetrol sulfate ester (C5H11SO7K) by gas-phase hydroxyl (OH) radicals at a relative humidity (RH) of 70.8 %. Real-time molecular composition of the aerosols is obtained by using a Direct Analysis in Real Time (DART) ionization source coupled to a high-resolution mass spectrometer. Aerosol mass spectra reveal that 3-methyltetrol sulfate ester can be detected as its anionic form (C5H11SO7-) via direct ionization in the negative ionization mode. Kinetic measurements reveal that the effective heterogeneous OH rate constant is measured to be 4.74±0.2×10-13 cm3 molecule−1 s−1 with a chemical lifetime against OH oxidation of 16.2±0.3 days, assuming an OH radical concentration of 1.5×106 molecules cm−3. Comparison of this lifetime with those against other aerosol removal processes, such as dry and wet deposition, suggests that 3-methyltetrol sulfate ester is likely to be chemically stable over atmospheric timescales. Aerosol mass spectra only show an increase in the intensity of bisulfate ion (HSO4-) after oxidation, suggesting the importance of fragmentation processes. Overall, potassium 3-methyltetrol sulfate ester likely decomposes to form volatile fragmentation products and aqueous-phase sulfate radial anion (SO4⚫-). SO4⚫- subsequently undergoes intermolecular hydrogen abstraction to form HSO4-. These processes appear to explain the compositional evolution of 3-methyltetrol sulfate ester during heterogeneous OH oxidation.
34
Svensson, Fredric G., and Lars Österlund. "Adsorption and Photo-Degradation of Organophosphates on Sulfate-Terminated Anatase TiO2 Nanoparticles." Catalysts 13, no. 3 (March 4, 2023): 526. http://dx.doi.org/10.3390/catal13030526.
Анотація:
The adsorption and photocatalytic degradation of trimethyl phosphate (TMP) and triethyl phosphate (TEP), two environmentally relevant model pollutants, have been studied on commercial anatase TiO2 and sulfate-terminated anatase TiO2 nanoparticles by means of operando diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and 2D correlation spectroscopy (2D COS). It is concluded that both TMP and TEP adsorb dissociatively on anatase TiO2, while on the sulfate-terminated anatase TiO2, TMP and TEP adsorb associatively. Upon UV illumination, TMP and TEP are completely oxidized on sulfate-terminated anatase TiO2, as evidenced by the evolution of the IR bands characteristic for water and carbon dioxide. In contrast, on anatase TiO2, UV illumination leads to the formation of stable surface-coordinated carboxylate products, which impedes complete oxidation. 2D COS analysis suggests that parallel reaction pathways occur during oxidation under UV illumination, viz. methoxide/ethoxide (ads) → carboxylates (ads) and methoxide/ethoxide (ads) → aldehydes (ads) → carboxylates (ads). A parallel reaction occurs on sulfated TiO2 that yields CO2 and H2O by direct radical reactions with the methoxide groups with little, or no, formation of surface-coordinated intermediates. Sulfated TiO2 favor the formation of aldehyde intermediates, with reaction rates 10 times and 30 times faster for TMP and TEM, respectively, compared with commercial anatase TiO2. About 37% (33%) and 32% (24%) of TMP (TEP) were degraded on sulfated-terminated TiO2 and pure TiO2, respectively, after the first 9 min of UV illumination. We show that the sulfate-functionalization of TiO2 has two main functions. First, it prevents the formation of strongly bonded bridging carboxylates, thereby alleviating deactivation. Second, it promotes full oxidation of the organic side-chains into carbon dioxide and water. Improved electron-hole separation by the electrophilic S(VI) in combination with the blocking of bridging reaction intermediates is proposed to contribute to the improved activity. The presented results give insights into how acidic surface modifications change adsorbate surface chemistries, which can be used to increase the sustained activity of low-temperature photocatalysts.
35
Krysenko, G. F., D. G. Epov, M. A. Medkov, and E. B. Merkulov. "Studying of possibility for breakdown of ilmenite concentrate with ammonium sulphate." Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 4, no. 312 (June 15, 2020): 22–30. http://dx.doi.org/10.31643/2020/6445.03.
Анотація:
The data on investigation of the possibility of breakdown of ilmenite concentrate of the Ariadnensky deposit in Primorsky Krai with ammonium sulfate are presented in the article. For study the ilmenite concentrate and ammonium sulfate interaction, the concentrate and (NH4)2SO4 were mixed based on the formation of sulfates of the main components of the concentrate and then double sulfates of the components of the concentrate and ammonium. The interaction was carried out in glassy carbon crucibles, which were placed in a muffle furnace controller company Nabertherm GmbH (Germany). The weight of sample was 10–40 g. Thermogravimetry, X-ray diffraction and atomic absorption analyses were used in the study. It was found that when the temperature of thermal decomposition of (NH4)2SO4 (3000С) is reached, the interaction of the main components of the concentrate with (NH4)2SO4 begins and proceeds in the temperature range of 300-3600С with the formation of a mixture of double salts well soluble in water - ammonium sulfate and iron compounds (NH4)2Fe2(SO4)3 and NH4Fe(SO4)2 and ammonium sulfate and titanyl of the composition (NH4)2TiO(SO4)2. The interaction at a temperature above 3600С leads to thermal decomposition of the formed double sulfates of ammonium and titanyl and ammonium and iron to sulfates and then oxides. It was shown that water leaching of the product of the interaction of ilmenite concentrate with (NH4)2SO4 at 3600С allows to extract practically all titanium and the bulk of iron to water in the form of well soluble double salts. The conditions for the titanium dioxide separation in the form of anatase from the water leaching solution were found.
36
Sinha, B. W., P. Hoppe, J. Huth, S. Foley, and M. O. Andreae. "Sulfur isotope analysis of individual aerosol particles – a new tool for studying heterogeneous oxidation processes in the marine environment." Atmospheric Chemistry and Physics Discussions 9, no. 1 (February 2, 2009): 3307–65. http://dx.doi.org/10.5194/acpd-9-3307-2009.
Анотація:
Abstract. Understanding the importance of the different oxidation pathways of sulfur dioxide (SO2) to sulfate is crucial for an interpretation of the climate effects of sulfate aerosols. Sulfur isotope analysis of atmospheric aerosol is a well established tool for identifying sources of sulfur in the atmosphere and assessment of anthropogenic influence. The power of this tool is enhanced by a new ion microprobe technique that permits isotope analysis of individual aerosol particles as small as 0.5 μm diameter. With this new single particle technique, different types of primary and secondary sulfates are first identified based on their chemical composition, and then their individual isotopic signature is measured. Our samples were collected at Mace Head, Ireland, a remote coastal station on the North Atlantic Ocean. Sea-salt-sulfate (10–60%), ammonium sulfate/sulfuric acid particles (15–65%), and non-sea-salt-sulfate (nss-sulfate) on aged salt particles all contributed significantly to sulfate loadings in our samples. The isotopic composition of secondary sulfates depends on the isotopic composition of precursor SO2 and the oxidation process. The fractionation with respect to the source SO2 is poorly characterized. In the absence of conclusive laboratory experiments, we consider the kinetic fractionation of −9‰ during the gas phase oxidation of SO2 by OH as suggested by Saltzman et al. (1983) and Tanaka et al. (1994) to be the most reasonable estimate for the isotope fractionation during gas phase oxidation of SO2 (αhom=0.991) and the equilibrium fractionation for the uptake of SO2(g) into the aqueous phase and the dissociation to HSO3− of +16.5‰ measured by Eriksen (1972a) to be the best approximation for the fractionation during oxidation in the aqueous phase (αhet=1.0165). The sulfur isotope ratio of secondary sulfate particles can therefore be used to identify the oxidation pathway by which this sulfate was formed. However, the fraction of heterogeneous and homogeneous oxidation pathway calculated is very sensitive to the isotope fractionation assumed for both pathways. Particles with known oxidation pathway (fine mode ammonium sulfate) are used to estimate the isotopic composition of the source SO2. It ranged from δ34SVCDT=0±3‰ to δ34SVCDT=(14±3)‰ under clean conditions and δ34SVCDT=(3±1)‰ under polluted condition. Condensation of H2SO4(g) onto sea salt aerosol produces an isotopic ratio that, when plotted against the sea-salt-sulfate content of the sample, lies on a mixing line between sea salt and ammonium sulfate. The contribution of heterogeneous oxidation is estimated based on the deviation of non-sea-salt-sulfate from this isotopic mixing line. The contribution of heterogeneous oxidation to nss-sulfate formation on aged sea salt sodium sulfate, magnesium sulfate gypsum and mixed sulfate particles under clean conditions is on average 10% for coarse and 25% for fine mode particles. Under polluted conditions, the contribution of heterogeneous oxidation to nss-sulfate formation increased to 60% on coarse mode and 75% on fine mode particles. However, large day-to-day variations in the contribution of heterogeneous oxidation to nss-sulfate formation occurred. Our results suggest that a~significant portion of SO2 in coastal regions is converted to fine mode ammonium sulfate/sulfuric acid particles (40–80% of nss-sulfate) and that condensation of H2SO4(g) contributes significantly even to the nss-sulfate in aged sea salt particles (20–85%).
37
Liu, Pengfei, Can Ye, Chaoyang Xue, Chenglong Zhang, Yujing Mu, and Xu Sun. "Formation mechanisms of atmospheric nitrate and sulfate during the winter haze pollution periods in Beijing: gas-phase, heterogeneous and aqueous-phase chemistry." Atmospheric Chemistry and Physics 20, no. 7 (April 7, 2020): 4153–65. http://dx.doi.org/10.5194/acp-20-4153-2020.
Анотація:
Abstract. A vast area in China is currently going through severe haze episodes with drastically elevated concentrations of PM2.5 in winter. Nitrate and sulfate are the main constituents of PM2.5, but their formations via NO2 and SO2 oxidation are still not comprehensively understood, especially under different pollution or atmospheric relative humidity (RH) conditions. To elucidate formation pathways of nitrate and sulfate in different polluted cases, hourly samples of PM2.5 were collected continuously in Beijing during the wintertime of 2016. Three serious pollution cases were identified reasonably during the sampling period, and the secondary formations of nitrate and sulfate were found to make a dominant contribution to atmospheric PM2.5 under the relatively high RH condition. The significant correlation between NOR, NOR = NO3-/(NO3-+NO2), and [NO2]2 × [O3] during the nighttime under the RH≥60 % condition indicated that the heterogeneous hydrolysis of N2O5 involving aerosol liquid water was responsible for the nocturnal formation of nitrate at the extremely high RH levels. The more often coincident trend of NOR and [HONO] × [DR] (direct radiation) × [NO2] compared to its occurrence with [Dust] × [NO2] during the daytime under the 30 % < RH < 60 % condition provided convincing evidence that the gas-phase reaction of NO2 with OH played a pivotal role in the diurnal formation of nitrate at moderate RH levels. The extremely high mean values of SOR, SOR = SO42-/(SO42-+SO2), during the whole day under the RH≥60 % condition could be ascribed to the evident contribution of SO2 aqueous-phase oxidation to the formation of sulfate during the severe pollution episodes. Based on the parameters measured in this study and the known sulfate production rate calculation method, the oxidation pathway of H2O2 rather than NO2 was found to contribute greatly to the aqueous-phase formation of sulfate.
38
Mészáros, A., and E. Mészáros. "Sulfate Formation on Elemental Carbon Particles." Aerosol Science and Technology 10, no. 2 (January 1989): 337–42. http://dx.doi.org/10.1080/02786828908959270.
39
Niedermeyer, Inge, Susanne Biedlingmaier, and Ahlert Schmidt. "Derepression of Arylsulfatase Activity by Sulfate Starvation in Chlorella fusca." Zeitschrift für Naturforschung C 42, no. 5 (May 1, 1987): 530–36. http://dx.doi.org/10.1515/znc-1987-0507.
Анотація:
Abstract Arylsulfatase activity was detected in the green alga Chlorella fusca 211-8b during sulfur starvation. No activity was present during growth on sulfate, whereas activity was found with sulfur sources as growth-limiting factor including L-cysteine and L-methionine. Arylsulfatase activity was found after transfer to sulfate starvation conditions after a lag-period of about 3 h; addition of cycloheximide prevented arylsulfatase formation, suggesting the participation of protein synthe sis. Addition of sulfate to cultures with active arylsulfatase led to a decay of this enzyme, whereas addition of sulfate and cycloheximide prevented this decay suggesting that protein synthesis is also needed for degradation of arylsulfatase activity. The Km for p-nitrophenyl sulfate was determined to be 0.8 mм. The activity of the arylsulfatase is not affected by sulfate or phosphate, however it is inhibited strongly by sulfite, cyanide and boric acid and therefore is classified according to Dogson and Spencer (Meth. Biochem. Anal. 4, 211-254 (1957) as an arylsulfatase of type I.
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Purnamaningsih, Nur'aini, Endah Retnaningrum, and Wahyu Wilopo. "PEMANFATAAN KONSORSIUM BAKTERI PEREDUKSI SULFAT DAN ZEOLIT ALAM DALAM PENGENDAPAN LOGAM Mn." Jurnal Penelitian Saintek 22, no. 1 (August 28, 2017): 37. http://dx.doi.org/10.21831/jps.v22i1.15311.
Анотація:
Tujuan dari penelitian ini adalah untuk mengetahui pengaruh penambahan zeolit alam Wonosari terhadap aktivitas Bakteri Pereduksi Sulfat dalam pengendapan logam Mn skala continous culture dan mengidentifikasi karakter biofilm Bakteri Pereduksi Sulfat oleh aktivitas konsorsium Bakteri Pereduksi Sulfat pada zeolit alam dalam skala continous culture. Tahap penelitian meliputi aktivasi zeolit, pengujian aktivitas konsorsium Bakteri Pereduksi Sulfat dalam skala continous culture; serta karakterisasi biofilm konsorsium Bakteri Pereduksi Sulfat. Konsorsium Bakteri Pereduksi Sulfat yang digunakan berasal dari kotoran kambing. Zeolit yang digunakan pada pengujian aktivitas konsorsium Bakteri Pereduksi Sulfat adalah zeolit alam Wonosari yang berukuran 0,8-1,2 cm. Hasil penelitian menunjukkan bahwa konsorsium Bakteri Pereduksi Sulfat pada bioreaktor dengan penambahan zeolit mempunyai aktivitas yang lebih efektif dibandingkan dengan bioreaktor tanpa penambahan zeolit, dimana pH meningkat menjadi pH 6,9; efisiensi pengendapan logam Mn sebesar 61,16%, serta nilai MPN yang lebih tinggi. Zeolit dalam bioreaktor dengan waktu pembentukan biofilm 5 hari dan 9 hari terlihat adanya biofilm konsorsium Bakteri Pereduksi Sulfat yang tumbuh melekat pada permukaan zeolit. The objective of this study were determining the effects of natural zeolite from Wonosari on the activites of Sulfate Reducing Bacteria in Mangan (Mn) sedimentation of continous culture scale, and identifying the biofilm character of Sulfate Reducing Bacteria on consortium activites on natural zeolite using continous culture scale. The first studies was activation of zeolites, followed by testing the activity of consortium activities of Sulfate Reduction Bacteria in continuous culture scales; and biofilm characterization of Sulfate Reducing Bacteria consortium. The consortium of Sulfate Reducing Bacteria derived from goat feces. The size of zeo natural zeolites used in the consortium activity test of Sulfate Reducing Bacteria in Mangan sedimentation was 0.8 to 1.2 cm. The results showed that the consortium of Sulfate Reducing Bacteria in the bioreactor with the addition of zeolite had an activity that was more effective than the bioreactor without the addition of zeolite, where the pH was increased to pH 6.9; Mangan sedimentation was 61,16%, and the higher MPN index. Zeolite in a bioreactor with biofilm formation in 5th days and 9th days seems that there were biofilm consortium of Sulfate Reducing Bacteria growing attached to the surface of the zeolite.
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Manktelow, P. T., K. S. Carslaw, G. W. Mann, and D. V. Spracklen. "Variable CCN formation potential of regional sulfur emissions." Atmospheric Chemistry and Physics Discussions 9, no. 1 (January 29, 2009): 3095–112. http://dx.doi.org/10.5194/acpd-9-3095-2009.
Анотація:
Abstract. Aerosols are short lived so their geographical distribution and impact on climate depends on where they are emitted. Previous model studies have shown that the mass of sulfate aerosol produced per unit sulfur emission (the sulfate burden potential) and the associated direct radiative forcing vary regionally because of differences in meteorology and photochemistry. Using a global model of aerosol microphysics, we show that the total number of aerosol particles produced per unit sulfur emission (the aerosol number potential) has a different regional variation to that of sulfate mass. The aerosol number potential of N. American and Asian emissions is calculated to be a factor of 3 to 4 times greater than that of European emissions, even though Europe has a higher sulfate burden potential. Pollution from North America and Asia tends to reach higher altitudes than European pollution so forms more new particles through nucleation. These regional differences in particle production mean that sulfur emissions from N. America and E. Asia produce cloud condensation nuclei up to 70% more efficiently than Europe. Taking account of the higher sulfate burden potential of Europe in these simulations shows that E. Asian sulfate produces CCN twice as effectively as European sulfate. The impact of regional sulfur emissions on particle concentrations is also much more widely spread than the impact on sulfate mass, due to efficient particle production in the free troposphere during long range transport. These results imply that regional sulfur emissions will have different climate forcing potentials through changes in cloud drop number.
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Maccarana, Marco, Sebastian Kalamajski, Mads Kongsgaard, S. Peter Magnusson, Åke Oldberg, and Anders Malmström. "Dermatan Sulfate Epimerase 1-Deficient Mice Have Reduced Content and Changed Distribution of Iduronic Acids in Dermatan Sulfate and an Altered Collagen Structure in Skin." Molecular and Cellular Biology 29, no. 20 (August 17, 2009): 5517–28. http://dx.doi.org/10.1128/mcb.00430-09.
Анотація:
ABSTRACT Dermatan sulfate epimerase 1 (DS-epi1) and DS-epi2 convert glucuronic acid to iduronic acid in chondroitin/dermatan sulfate biosynthesis. Here we report on the generation of DS-epi1-null mice and the resulting alterations in the chondroitin/dermatan polysaccharide chains. The numbers of long blocks of adjacent iduronic acids are greatly decreased in skin decorin and biglycan chondroitin/dermatan sulfate, along with a parallel decrease in iduronic-2-O-sulfated-galactosamine-4-O-sulfated structures. Both iduronic acid blocks and iduronic acids surrounded by glucuronic acids are also decreased in versican-derived chains. DS-epi1-deficient mice are smaller than their wild-type littermates but otherwise have no gross macroscopic alterations. The lack of DS-epi1 affects the chondroitin/dermatan sulfate in many proteoglycans, and the consequences for skin collagen structure were initially analyzed. We found that the skin collagen architecture was altered, and electron microscopy showed that the DS-epi1-null fibrils have a larger diameter than the wild-type fibrils. The altered chondroitin/dermatan sulfate chains carried by decorin in skin are likely to affect collagen fibril formation and reduce the tensile strength of DS-epi1-null skin.
43
MATSUI, Hiroshi, Kayoko AMITA, Genzo HASHIZUME, Gin-ya ADACHI, and Jiro SHIOKAWA. "The formation of needlelike .ALPHA.-calcium sulfate hemihydrate from calcium sulfite hemihydrate." NIPPON KAGAKU KAISHI, no. 12 (1987): 2279–85. http://dx.doi.org/10.1246/nikkashi.1987.2279.
44
Tiwari, Vaibhav, Gerdy B. ten Dam, Beatrice Y. J. T. Yue, Toin H. van Kuppevelt, and Deepak Shukla. "Role of 3-O -sulfated heparan sulfate in virus-induced polykaryocyte formation." FEBS Letters 581, no. 23 (August 24, 2007): 4468–72. http://dx.doi.org/10.1016/j.febslet.2007.08.029.
45
Wang, Gehui, Renyi Zhang, Mario E. Gomez, Lingxiao Yang, Misti Levy Zamora, Min Hu, Yun Lin, et al. "Persistent sulfate formation from London Fog to Chinese haze." Proceedings of the National Academy of Sciences 113, no. 48 (November 14, 2016): 13630–35. http://dx.doi.org/10.1073/pnas.1616540113.
Анотація:
Sulfate aerosols exert profound impacts on human and ecosystem health, weather, and climate, but their formation mechanism remains uncertain. Atmospheric models consistently underpredict sulfate levels under diverse environmental conditions. From atmospheric measurements in two Chinese megacities and complementary laboratory experiments, we show that the aqueous oxidation of SO2by NO2is key to efficient sulfate formation but is only feasible under two atmospheric conditions: on fine aerosols with high relative humidity and NH3neutralization or under cloud conditions. Under polluted environments, this SO2oxidation process leads to large sulfate production rates and promotes formation of nitrate and organic matter on aqueous particles, exacerbating severe haze development. Effective haze mitigation is achievable by intervening in the sulfate formation process with enforced NH3and NO2control measures. In addition to explaining the polluted episodes currently occurring in China and during the 1952 London Fog, this sulfate production mechanism is widespread, and our results suggest a way to tackle this growing problem in China and much of the developing world.
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Marriott, Robert A., Payman Pirzadeh, Juan J. Marrugo-Hernandez, and Shaunak Raval. "Hydrogen sulfide formation in oil and gas." Canadian Journal of Chemistry 94, no. 4 (April 2016): 406–13. http://dx.doi.org/10.1139/cjc-2015-0425.
Анотація:
Hydrogen sulfide (H2S) can be a significant component of oil and gas upstream production, where H2S can be naturally generated in situ from reservoir biomass and from sulfate-containing minerals through microbial sulfate reduction and (or) thermochemical sulfate reduction. On the other hand, the technologies employed in oil and gas production, especially from unconventional resources, also can contribute to generation or delay of appearance of H2S. Steam-assisted gravity drainage and hydraulic fracturing used in production of oil sands and shale oil/gas, respectively, can potentially convert the sulfur content of the petroleum into H2S or contribute excess amounts of H2S during production. A brief overview of the different classes of chemical reactions involved in the in situ generation and release of H2S is provided in this work. Speciation calculations and reaction mechanisms are presented to explain why thermochemical sulfate reduction progresses at faster rates under low pH. New studies regarding the degradation of a hydraulic fracture fluid additive (sodium dodecly sulfate) are reported for T = 200 °C, p = 17 MPa, and high ionic strengths. The absence of an ionic strength effect on the reaction rate suggests that the rate-limiting step involves the reaction of neutral species, such as elemental sulfur. This is not the case with other thermochemical sulfate reduction studies at T > 300 °C. These two different kinetic regimes complicate the goal of extrapolating laboratory results for field-specific models for H2S production.
47
Hocking, D., T. J. Ferro, and A. Johnson. "Dextran sulfate and heparin sulfate inhibit platelet-activating factor-induced pulmonary edema." Journal of Applied Physiology 72, no. 1 (January 1, 1992): 179–85. http://dx.doi.org/10.1152/jappl.1992.72.1.179.
Анотація:
We tested the hypothesis that dextran sulfate and heparin sulfate inhibit platelet-activating factor- (PAF) induced pulmonary edema in the isolated perfused guinea pig lung via a charge-dependent mechanism. Dextran sulfate prevented the changes in pulmonary capillary pressure (Ppc, 7.8 +/- 0.9 vs. 14.0 +/- 0.7 cmH2O), lung weight gain (dW, +0.48 +/- 0.29 vs. +8.41 +/- 2.07 g), and pulmonary edema formation or wet-to-dry weight ratio [(W-D)/D, 6.5 +/- 0.3 vs. 13.2 +/- 2.6] occurring 60 min after PAF infusion (10(-11) M) into an isolated lung. The unsulfated form of dextran had no protective effect [Ppc, dW, and (W-D)/D, 11.9 +/- 1.4 cmH2O, +5.33 +/- 2.18 g, and 11.2 +/- 3.2, respectively]. The unrelated anionic compound, heparin sulfate, also inhibited the PAF response [Ppc, dW, and (W-D)/D, 7.0 +/- 0.5 cmH2O, +0.61 +/- 0.32 g, and 6.1 +/- 0.2, respectively], whereas the partially desulfated form of heparin was not effective in inhibiting PAF-induced edema [Ppc, dW, and (W-D)/D, 15.1 +/- 0.7 cmH2O, +6.07 +/- 1.58 g, and 10.0 +/- 1.2, respectively]. When the metachromatic dye crystal violet was used as an indicator of charge interactions, the sulfated compounds interacted with PAF in vitro. The data indicate that PAF-induced pulmonary edema is inhibited by sulfated polysaccharides, possibly via a charge interaction between negatively charged compounds and PAF.
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Li, Chang Cheng, Yan Yao, and Ling Wang. "Accelerate Thaumasite Formation in Cement-Limestone Powder Paste by Internal Adding Method." Advanced Materials Research 250-253 (May 2011): 22–27. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.22.
Анотація:
Cement-limestone powder pastes added with 10% magnesium sulfate, sodium sulfate, and calcium sulfate respectively were stored in water at (5±2) °C to accelerate thaumasite formation. The pastes were inspected visually at intervals. And the formation of thaumasite was identified and confirmed by X-ray diffraction (XRD), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). The results show that internal adding sulfate in cement-limestone powder paste is an efficient way to accelerate thaumasite formation, and the accelerated effect is magnesium sulfate> sodium sulfate> calcium sulfate. Cement-limestone paste containing 10% magnesium sulfate totally turns into grey-white mushy materials after 6 months immersion, and products are mainly thaumasite and gypsum. In addition, the amount of thaumasite increases along with time of internal sulfate attack in 15 months. XRD, IR, and NMR are powerful and reliable tools for identification of thaumasite in cement-based materials.
49
Halkjær Nielsen, Per. "Sulfur Sources for Hydrogen Sulfide Production in Biofilms from Sewer Systems." Water Science and Technology 23, no. 7-9 (April 1, 1991): 1265–74. http://dx.doi.org/10.2166/wst.1991.0578.
Анотація:
The relative significance of different inorganic and organic sulfur compounds on the sulfide production in anaerobic biofilms grown on domestic wastewater was investigated. The objective was to improve the understanding of microbial processes in dynamic systems and to evaluate the equations used to predict sulfide formation in pressure mains. Biofilms originally grown on domestic wastewater with sulfate as the only electron acceptor were also able to reduce sulfite and thiosulfate. The bacteria preferred thiosulfate to sulfate if both were present and the sulfide production rates increased with a factor of 1.5. Disproportionation of thiosulfate to equal amounts of sulfide and sulfate was demonstrated to take place in the biofilms but only at low concentrations of organic substrates. Some sulfide production from the organic sulfur compounds cysteine and methionine was observed. The rates were, however, insignificant compared to sulfide production from sulfate reduction in wastewater. Biofilm activity measured as the zero order volume constant (kof) was around 0.18 mg SO4-S cm−3 h−1 at 20 °C. If the biofilms were grown on domestic wastewater enriched with sulfite or thiosulfate, kof increased around two times. The sulfide production rate from both sulfite and thiosulfate was found to be considerably higher than the rate from sulfate in these biofilms. The results were modeled using biofilm kinetics which showed that the presence of sulfite or thiosulfate in the wastewater strongly affected the potential sulfide production and could in some cases be a limiting compound besides organic matter. Knowledge about the presence of sulfur compounds other than sulfate in wastewater, e.g. from industrial sources, may therefore be very important to forecast sulfide buildup in sewer systems.
50
Li, Guohui, Naifang Bei, Junji Cao, Rujin Huang, Jiarui Wu, Tian Feng, Yichen Wang, et al. "A possible pathway for rapid growth of sulfate during haze days in China." Atmospheric Chemistry and Physics 17, no. 5 (March 7, 2017): 3301–16. http://dx.doi.org/10.5194/acp-17-3301-2017.
Анотація:
Abstract. Rapid industrialization and urbanization have caused frequent occurrence of haze in China during wintertime in recent years. The sulfate aerosol is one of the most important components of fine particles (PM2. 5) in the atmosphere, contributing significantly to the haze formation. However, the heterogeneous formation mechanism of sulfate remains poorly characterized. The relationships of the observed sulfate with PM2. 5, iron, and relative humidity in Xi'an, China have been employed to evaluate the mechanism and to develop a parameterization of the sulfate heterogeneous formation involving aerosol water for incorporation into atmospheric chemical transport models. Model simulations with the proposed parameterization can successfully reproduce the observed sulfate rapid growth and diurnal variations in Xi'an and Beijing, China. Reasonable representation of sulfate heterogeneous formation in chemical transport models considerably improves the PM2. 5 simulations, providing the underlying basis for better understanding the haze formation and supporting the design and implementation of emission control strategies.