Littérature scientifique sur le sujet « Sulfate groups »
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Articles de revues sur le sujet "Sulfate groups"
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Arnoštová, Libuše, Ivan Černý, Vladimír Pouzar et Pavel Drašar. « Synthesis of 5α-Cholestane Type Glycoside Sulfates ». Collection of Czechoslovak Chemical Communications 58, no 5 (1993) : 1180–90. http://dx.doi.org/10.1135/cccc19931180.
Texte intégralRésumé :
Synthesis of steroid glycoside sulfates sulfated both on the steroid skeleton and in sugar part are presented. Sodium salts of 5α-cholestane-3β,6α-diol 6-β-D-glucoside 3-sulfate V and 3-β-D-glucoside 6-sulfate XI were prepared from 3β-(2-tetrahydropyranyloxy)-5α-cholestan-6α-ol (I) using acetyl and methoxymethyl groups for temporary protection. Sulfation in the sugar part was at first checked in pregnane series and triethylammonium salts of 3β-(β-D-glucopyranosyloxy)pregn-5-en-20-one 6'-sulfate (XXVI) and 4'-sulfate 2',3'-diacetate XXVII were prepared. Application of the method on cholestane derivatives gave triethylammonium salt of 5α-cholestan-3β-yl β-D-glucopyranoside-6-sulfate (XXXI).
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Reinehr, Thomas, Alberto Sánchez-Guijo, Nina Lass et Stefan A. Wudy. « Higher steroid sulfation is linked to successful weight loss in obese children ». Endocrine Connections 7, no 10 (octobre 2018) : 1020–30. http://dx.doi.org/10.1530/ec-18-0233.
Texte intégralRésumé :
Objective Little information is available on the steroid sulfates profile in obese children. Therefore, we examined whether sulfated steroids are linked with weight status and associated comorbidities in obese children. Methods We analyzed 66 obese children (mean age 10.5 ± 2.5 years, 57.6% female, 53.9% prepubertal, mean BMI 27.0 ± 4.6 kg/m2, 50% with BMI-SDS reduction >0.5, 50% without BMI-SDS reduction) who participated in an outpatient 1-year intervention program based on exercise, behavior and nutrition therapy. We measured intact sulfated steroids (cholesterol sulfate (CS), pregnenolone sulfate (PregS), 17αOH pregnenolone sulfate (17OH-PregS), 16αOH dehydroepiandrosterone sulfate (16OH-DHEAS), DHEAS, androstenediol-3-sulfate, androsterone sulfate and epiandrosterone sulfate) by LC–MS/MS, and insulin resistance index HOMA, lipids, blood pressure at baseline and 1 year later. Results All sulfated steroids except 17OH-PregS, 16OH-DHEAS, androsterone sulfate and epiandrosterone sulfate were higher in boys compared to girls. Concentrations of CS before intervention were higher in children who lost weight. After 1 year of treatment, both groups showed increased levels of DHEAS, 16OH-DHEAS and androstenediol-3-sulfate, but PregS was only increased in children with weight loss. None of the steroid sulfates was significantly related to cardiovascular risk factors or HOMA except 17OH-PregS, which was associated with systolic blood pressure both in cross-sectional (β-coefficient: 0.09 ± 0.07, P = 0.020) and longitudinal analyses (β-coefficient: 0.06 ± 0.04, P = 0.013) in multiple linear regression analyses. Conclusions Since higher steroid sulfation capacity was associated with successful weight intervention in children disruption of sulfation may be associated with difficulties to lose weight. Future studies are necessary to prove this hypothesis.
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Hobkirk, R., et 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 (1 août 1985) : 785–91. http://dx.doi.org/10.1139/o85-100.
Texte intégralRésumé :
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.
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Drouet, B., S. Matou, P. A. S. Mourão, A. Bros, D. Letourneur, A. M. Fischer et J. Tapon-Bretaudière. « Modulation of Vascular Human Endothelial and Rat Smooth Muscle Cell Growth by a Fucosylated Chondroitin Sulfate from Echinoderm ». Thrombosis and Haemostasis 84, no 08 (2000) : 332–37. http://dx.doi.org/10.1055/s-0037-1614016.
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SummaryFucosylated chondroitin sulfate is a glycosaminoglycan extracted from the sea cucumber Ludwigothurea grisea. This polysaccharide has the same structure as a mammalian chondroitin sulfate but some of the glucuronic acid residues display sulfated fucose branches. Anticoagulant and antithrombotic properties of fucosylated chondroitin sulfate have already been described. In order to further investigate its potential therapeutic use as an antithrombotic agent, we studied its effect on vascular smooth muscle cell (SMC) proliferation and endothelial cell proliferation, migration and Tissue Factor Pathway Inhibitor (TFPI) release. The experiments were performed on SMC from rat thoracic aorta and on human umbilical vein endothelial cell (HUVEC) in culture with or without added fibroblast growth factors (FGF-1 and FGF-2). Our results showed that: (i) fucosylated chondroitin sulfate had a strong inhibitory effect on SMC proliferation (IC50 =10 ± 5 µg/ml) and (ii) no effect on HUVEC proliferation and migration assays, in the absence of exogenous FGF, while heparin had inhibitory effects; (iii) fucosylated chondroitin sulfate (10 µg/ml) enhanced FGF-1 and FGF-2 induced HUVEC proliferation by 45% (145.4 ± 7.2%) and 27% (126.9 ± 4.2%), respectively; (iv) on FGF-induced HUVEC migration, fucosylated chondroitin sulfate (10 µg/ml) had a strong enhancing effect with FGF-1, +122% (222.2 ± 15.8%), three times higher than that of heparin, and a lower enhancing effect with FGF-2, +43% (142.7 ± 4.6%), whereas heparin had no effect; (v) fucosylated chondroitin sulfate stimulated TFPI release, mainly on the free form, +98% (198.2 ± 25.%). In addition, the structural features of the polysaccharide associated with its biological activity were resolved using chemically modified fucosylated chondroitin sulfates. Sulfated fucose branches groups are essential to the potentiating effect of the polysaccharide on HUVEC proliferation and migration. Surprisingly, removal of fucose branches from the fucosylated chondroitin sulfate did not abolish TFPI release. Finally, partial reduction of the glucuronic acid carboxyl groups limited the potentiating effect on HUVEC proliferation and migration but did not affect TFPI release. In conclusion, this fucosylated chondroitin sulfate from invertebrate origin reveals useful properties for an antithrombotic agent: inhibition of SMC proliferation, enhancement of endothelium wound repair and TFPI release. These properties on vascular cells, associated with a low bleeding tendency and an antithrombotic activity, strongly suggest its potential use as a new therapeutic agent in arterial thrombosis and restenosis, with a more favorable effect than heparin.
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Fishbain, Susan, Jesse G. Dillon, Heidi L. Gough et David A. Stahl. « Linkage of High Rates of Sulfate Reduction in Yellowstone Hot Springs to Unique Sequence Types in the Dissimilatory Sulfate Respiration Pathway ». Applied and Environmental Microbiology 69, no 6 (juin 2003) : 3663–67. http://dx.doi.org/10.1128/aem.69.6.3663-3667.2003.
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ABSTRACT Diversity, habitat range, and activities of sulfate-reducing prokaryotes within hot springs in Yellowstone National Park were characterized using endogenous activity measurements, molecular characterization, and enrichment. Five major phylogenetic groups were identified using PCR amplification of the dissimilatory sulfite reductase genes (dsrAB) from springs demonstrating significant sulfate reduction rates, including a warm, acidic (pH 2.5) stream and several nearly neutral hot springs with temperatures reaching 89�C. Three of these sequence groups were unrelated to named lineages, suggesting that the diversity and habitat range of sulfate-reducing prokaryotes exceeds that now represented in culture.
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Kazachenko, Aleksandr S., Natalia Yu Vasilieva, Yaroslava D. Berezhnaya, Olga Yu Fetisova, Valentina S. Borovkova, Yuriy N. Malyar, Irina G. Sudakova et al. « Sulfation of Birch Wood Microcrystalline Cellulose with Sulfamic Acid Using Ion-Exchange Resins as Catalysts ». Polymers 15, no 5 (23 février 2023) : 1116. http://dx.doi.org/10.3390/polym15051116.
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Cellulose sulfates are important biologically active substances with a wide range of useful properties. The development of new methods for the production of cellulose sulfates is an urgent task. In this work, we investigated ion-exchange resins as catalysts for the sulfation of cellulose with sulfamic acid. It has been shown that water-insoluble sulfated reaction products are formed in high yield in the presence of anion exchangers, while water-soluble products are formed in the presence of cation exchangers. The most effective catalyst is Amberlite IR 120. According to gel permeation chromatography, it was shown that the samples sulfated in the presence of the catalysts KU-2-8, Purolit s390 plus, and AN-31 SO42− underwent the greatest degradation. The molecular weight destribution profiles of these samples are noticeably shifted to the left towards low-molecular-weight compounds with an increase in fractions in the regions Mw ~2.100 g/mol and ~3.500 g/mol, indicating the growth of microcrystalline cellulose depolymerization products. The introduction of a sulfate group into the cellulose molecule is confirmed using FTIR spectroscopy by the appearance of absorption bands at 1245–1252 cm−1 and 800–809 cm−1, which correspond to the vibrations of the sulfate group. According to X-ray diffraction data, amorphization of the crystalline structure of cellulose is observed during sulfation. Thermal analysis has shown that with an increase in the content of sulfate groups in cellulose derivatives, thermal stability decreases.
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Kazachenko, Aleksandr Sergeyevich, Vladimir Aleksandrovich Levdansky, Aleksandr Vladimirovich Levdansky et Boris Nikolayevich Kuznetsov. « MATHEMATICAL OPTIMIZATION OF THE PROCESS OF BIRCH WOOD XYLAN SULFATION BY SULFAMIC ACID IN N, N-DIMETHYLFORMAMIDE MEDIUM ». chemistry of plant raw material, no 2 (10 juin 2021) : 87–94. http://dx.doi.org/10.14258/jcprm.2021027558.
Texte intégralRésumé :
The effect of temperature and duration of sulfation of birch wood xylan by sulfamic acid in N, N-dimethylformamide (DMF) medium in the presence of urea on the yield of sulfated xylan and on the sulphur content was studied. By mathematical optimization, the sulfation conditions have been established allowing to achieve a high yield of the obtained xylan sulfates with a high sulphur content. Under optimal sulfation conditions: temperature 100±3 °C, duration 1.5 hours, the yield of sulfated xylan reaches to 63% mas. and the content of sulfur – 17.6% mas. The presence of sulfate groups in sulfated xylan samples obtained under optimal conditions was confirmed by elemental analysis and FTIR and 13C NMR spectroscopy.
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Kazachenko, Aleksandr S., Yuriy N. Malyar et Anna S. Kazachenko. « Synthesis of Galactomannan Sulfate-Citrate ». Materials Science Forum 1049 (11 janvier 2022) : 218–23. http://dx.doi.org/10.4028/www.scientific.net/msf.1049.218.
Texte intégralRésumé :
Sulfated derivatives of polysaccharides have anticoagulant, hypolipedimic and other biological activity. In this work, a complex mixed ester of galactomannan, its sulfate-citrate, was obtained for the first time. The introduction of citrate and sulfate groups was proved by FTIR spectroscopy by the appearance of corresponding absorption bands. It was shown by X-ray diffraction that the introduction of the citrate group leads to the amorphization of the galactomannan structure.
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Kim, B. Moon, et K. Barry Sharpless. « Cyclic sulfates containing acid-sensitive groups and chemoselective hydrolysis of sulfate esters ». Tetrahedron Letters 30, no 6 (1989) : 655–58. http://dx.doi.org/10.1016/s0040-4039(01)80274-4.
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Farzan, Michael, Christine E. Schnitzler, Natalya Vasilieva, Doris Leung, Jens Kuhn, Craig Gerard, Norma P. Gerard et 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 (7 mai 2001) : 1059–66. http://dx.doi.org/10.1084/jem.193.9.1059.
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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.
Thèses sur le sujet "Sulfate groups"
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Mandarini, Elisabetta. « Decoding the role of HSPGs in tumor onset and progression through use of branched peptide probe ». Doctoral thesis, Università di Siena, 2020. http://hdl.handle.net/11365/1094789.
Texte intégralRésumé :
Heparan sulfate Proteoglycans (HSPGs) play a number of signaling and structural roles in tumor progression and metastasis spread. The biological function of HSPGs resides in their ability of interaction with many different types of ligands like growth factors, morphogens, chemokines and proteins of extracellular matrix (ECM). These bindings activate signaling pathways that modulate major transformations of cancer cells, leading to tumor growth, migration, invasion and metastasis. HSPGs are over-expressed on cancer cell membranes. The tetra-branched peptide NT4 binds with high selectivity to different human cancer cells and tissues. Its ability to discriminate between tumor and healthy tissues resides in the high-affinity binding to HSPGs and can be exploited by conjugating NT4 with different functional units, like chemotherapeutical drugs and tracers for cancer cell imaging and therapy. In this work, we test NT4 ability to interfere with processes mediated by HSPGs in tumor cell adhesion, migration and matrix invasiveness. Since HSPGs modulate also neo-angiogenesis, because of their expression by endothelial cells of microvessels that generate new vasculature, we focus also on NT4 role in endothelial cell proliferation, migration and tube formation, in the presence of Fibroblast Growth Factor-2 (FGF-2). Since the internalization and trafficking behaviour of HSPGs seems to reveal a clathrin and caveolin- independent, but dynamin-dependent endocytic pathway, we investigate
the pathway used by NT4 to enter cells. Last, but not least, we radiolabel NT4 with 18F in order to measure tumor uptake and whole-body biodistribution in a mouse model of breast cancer, using in vivo PET imaging. NT4-HSPG interactions and consequent modulation of signaling pathways can prove the importance of NT4 peptide as a specific tool to enlighten the role of HSPG in tumor onset and progression.
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Ahmed, Yassir Ahmed Mohmed Ali. « Heparan sulfate-protein interactions : evidence for sulfate group-dependent selectivity ». Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539728.
Texte intégralRésumé :
Heparan sulfates (HS) are a family of structurally diverse, sulfated polysaccharides located at the cell surface and in the extracellular matrix. They are distributed widely in virtually all metazoan organisms. The structural diversity occurs via variability in the positions of sulfation along the HS chain and in (l L-iduronic acid and D› glucuronic acid substitutions. There is now strong evidence that these molecules perform diverse functions in vivo through their ability to regulate the activity of different proteins. A wide variety of proteins have been found to be ligands for liS, including growth factors, cytokines, receptors, adhesion and matrix molecules, enzymes, coagulation factors and a variety of bacterial and viral coat proteins. Hence, there is a very significant need to determine the molecular basis of HS activity and HS-protein interactions, addressing important issues such as the degree of molecular selectivity. In this study, two model protein systems were selected to test the hypothesis that selective saccharide sequence and sulfation patterns regulate protein binding and activity. In the first model, heparin and chemically modified heparin saccharides were screened for Slit and Robo binding and activity, as signalling by Slit requires two receptors, Robo transmembrane proteins and HS. How liS controls Slit-Robo signalling is unclear. Competition and direct enzyme linked immunoassay (ELISA) data showed that heparin derivatives enhance the affinity of Slit-Robo binary and ternary complexes. Analytical gel filtration chromatography demonstrated that Slit associates with a soluble Robo fragment and heparin derivatives to form a ternary complex. Furthermore, retinal growth cone collapse triggered by Slit requires cell surface HS or exogenously added heparin derivatives. The data indicate a complex relationship between HS binding and Slit-Robo proteins, which support selectivity in regulation of signalling responses, but do not suggest requirement for strictly defined sequence. In the second model, HS saccharides were prepared by heparinase treatment of porcine mucosal HS and purified by size-exclusion and SAX-IIPLC chromatography. Purified or semi-purified complex sulfated HS 6-mer and 8-mer sequences were prepared. This library was screened for binding to FGF-l and FGF-2 using a competition ELISA, and for corresponding bioactivity (regulation of FGF-l and FGF-2 signalling using a BaF3 cell assay with defined FGF receptors). This screen identified fractions that bound and activated these ligands, and ones that did not. Selected structures were subjected to activity analysis after further separation using ion-pairing reverse phase (IPRP-HPLC). Structures with similar or identical size and sulfation content, but distinct sulfation sequences, differed widely in their bioactivity, though binding data alone did not necessarily predict activity. The results provided information that supports the view that a significant degree of specificity for activation of FGF biological activity is encoded in the complex sulfation sequences observed in lIS chains. However, is not simply related to sulfation pattern. Over~ll: the results from these two model protein systems suggest that the degree of selectiVIty or specificity of HS structures for regulation of biological activity is complex, and varies according to the proteins involved. Nevertheless, they provide the basis for lIS to act as an important modulator of protein function in a wide variety of biological systems.
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Proud, Andrew D. « Development of a protecting group for sulfate esters ». Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/12804.
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This work describes the development of a protecting group for sulfate monoesters in carbohydrates. After initial trial studies, the trifluoroethyl ester was selected as a suitable protecting group. The ester was formed from the sulfate by treatment with trifluoro diazoethane. This protection method is shown to be compatible with other common protecting groups used in carbohydrate chemistry. The protecting group is proven to be stable to the manipulations of many other protecting groups. The utility of monosaccharides incorporating protected sulfate esters in synthesis has been examined. It has been proven that they are useful and versatile building blocks in the synthesis of more complex structures. Selective cleavage of the trifluoroethyl ester was achieved with potassium tert-butoxide. The mechanism for this deprotection reaction has been studied and this investigation has led to the advancement of alternative deprotection methods.
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Arai, Milton Hideaki. « Papel da atividade física regular realizada durante vários anos na função imune do idoso ». Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/5/5144/tde-14102014-093413/.
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A proposta principal deste estudo foi de avaliar o efeito da prática regular de atividade física por longos anos na imunossenescência, isto é, nas alterações que o sistema imune sofre com o envelhecimento. Para tal, comparou-se os resultados dos exames imunológicos de 20 idosos praticantes de corrida (idade média = 67 anos) aos de 20 idosos sedentários (idade média = 66 anos) e 10 jovens sedentários (idade média = 26 anos). Os idosos corredores eram praticantes da modalidade em média nos últimos 23 anos e vinham percorrendo uma distância semanal média de 39 quilômetros. O consumo máximo de oxigênio (VO2 max) deles foi 52% maior do que o dos idosos sedentários, atingindo valores similares aos dos jovens. Os parâmetros imunológicos analisados foram: contagem de linfócitos e seus subtipos, resposta proliferativa dos linfócitos T a mitógenos, atividade citotóxica das células natural killer e produção de citocinas (interleucinas 2, 3, 4, 6, 10 e 12). A dosagem das mesmas citocinas no soro também foi realizada, porém somente nos dois grupos de idosos. Os idosos corredores apresentaram resposta proliferativa dos linfócitos T a OKT-3 e produção de interleucina-2 significativamente maiores do que as dos idosos sedentários. Eles apresentaram também uma produção de interleucina-3 significativamente menor do que a dos seus pares sedentários. Por outro lado, não apresentaram diferença significativa destes parâmetros em relação aos jovens. Os níveis séricos das interleucinas 3, 6 e 12 dos idosos corredores foram significativamente menores do que os dos idosos sedentários. A influência da prática de atividade física regular sobre os níveis séricos do hormônio de crescimento, da testosterona e da dehidroepiandrosterona sulfato (DHEAS), que sofrem redução com o envelhecimento (\"endocrinossenescência\"), também foi estudada. Não houve diferença significativa entre os níveis séricos destes hormônios anabólicos dos idosos corredores e dos idosos sedentários. O efeito da atividade física regular sobre a beta-endorfina também foi avaliado. Os idosos corredores não apresentaram diferença significativa nos níveis séricos deste neuropeptídeo em relação aos idosos sedentários. Em virtude do possível envolvimento do sistema endócrino na imunossenescência, avaliou-se a correlação entre os hormônios anabólicos e as citocinas. Não se constatou correlação relevante entre eles, especialmente entre a DHEAS e a interleucina-6. Os resultados indicam que a prática regular de atividade física por longos anos tem o potencial de desacelerar a imunossenescênciaThe main objective of this study was to assess the effect of regular practice of physical activity on immunosenescence, that is, the changes that occur when the immune system is affected by aging. The results of immune tests conducted on 20 elderly runners (mean age = 67 years) were compared to those of 20 elderly sedentary individuals (mean age = 66 years) and to those of 10 young sedentary individuals (mean age = 26 years). On average, the elderly runners had practiced this activity for the last 23 years, running a mean weekly distance of 39 kilometers. Their maximum oxygen consumption (VO2 max) was 52% higher than that of sedentary elderly group, and similar to that of the group of younger individuals. The immune parameters studied were: lymphocyte and lymphocyte subtype counts, the proliferative response of T-lymphocytes to mitogens, cytotoxic activity of natural killer cells and production of cytokines (interleukins 2, 3, 4, 6, 10 and 12). The same cytokines were measured in serum, but only in the two groups of elderly people. Elderly runners presented a significantly higher proliferative response of T-lymphocytes to OKT-3 as well as interleukin-2 production than the sedentary group. The production of interleukin-3 was also significantly lower in the group of runners. On the other hand, the results of these parameters did not differ significantly from those of young subjects. Serum levels of interleukins 3, 6, and 12 were significantly lower in elderly runners than in sedentary individuals. The impact of regular physical activity on serum levels of growth hormone, testosterone, and dehydroepiandrosterone sulfate (DHEAS), which are affected by aging (\"endocrinosenescence\"), was also studied. The serum levels of these anabolic hormones did not differ significantly between the groups of elderly runners and the elderly sedentary individuals. When the impact of regular physical activity on beta-endorphin was studied, again no significant difference in the serum levels of this neuropeptide was found between the two elderly groups. Owing to the possible involvement of the endocrine system in immunosenescence, the correlation between anabolic hormones and cytokines was assessed. No relevant correlation was found, especially between DHEAS and interleukin-6. The results indicate that the regular practice of physical activity for several years may delay immunosenescence
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Kotler, Julia Michelle. « Biosignature storage in sulfate minerals- synthetic and natural investigations of the jarosite group minerals ». The University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-08062009-143516/.
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The discovery of jarosite on Mars in 2004 generated increased interest in the properties of the mineral related to the search for life on other planets. Several studies indicate that the formation of jarosite can be linked to biological activity on Earth and biomolecules such as amino acids have been found associated with terrestrial jarosite samples. A series of natural and synthetic investigations using different jarosite end-members has been conducted and is presented in this dissertation to investigate the possibility that jarosite can store biosignatures. Natural samples were analyzed by x-ray diffraction, elemental carbon analysis and laser-desorption Fourier transform mass spectrometry (LD-FTMS) and were found to contain the amino acid glycine. Synthetic experiments were conducted in which the different end-members were synthesized in the presence of glycine as well as the amino acid alanine and the amino acid breakdown product methylamine. These samples were analyzed by x-ray diffraction, neutron diffraction, LD-FTMS and thermogravimetric analysis (TGA) techniques. Results of these experiments show that the detection of the biosignature and the effect that biomolecule has on the jarosite minerals is dependent on the end-member and indicate that the jarosite minerals are an excellent target for detecting potential signs of past life on other planets.
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Katragkou, Eleni. « Aircraft based measurements of atmospheric sulfur dioxide and ground based measurements of gaseous sulfur (VI) in the simulated internal flow of an aircraft engine implications for atmospheric aerosol formation / ». [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969654588.
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Matthews, Richard P. « Ion Pairing in Aqueous Metal Sulfates and Platinum Group Metal Ammonium Solutions ». Doctoral thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/6330.
Texte intégralRésumé :
The structure and dynamics of ions and ion pairs in solution play an integral part in several biological and chemical processes. Historically the calculation of ion pair association constants from computer simulations has been complicated due to the difficulty in validating metal ion force fields for solution simulations. In this thesis a force field for divalent metal ions in metal sulfate solutions (i.e. Mg2+SO4 2-, Ca2+SO4 2-, Mn2+SO4 2-, Fe2+SO4 2-, Co2+SO4 2-, Ni2+SO4 2-, Cu2+SO4 2- and Zn2+SO4 2-) important in physical and biophysical experiments is produced. Potential of mean force calculations are used to provide ion pair free energy profiles and free energy perturbation calculations are used to calibrate the potential of mean force (PMF) from which association constants for ion pairs can be produced for these metal sulfate solutions. The calibrated free energy profiles result in calculated association constants that are in excellent agreement with available experimental data where available. Consequently the force field has been shown to be accurate for simulations of biophysical and physical systems. Furthermore the method, proposed in this thesis, for calibrating PMFs and calculating detailed association constants from those curves can most likely be used for complex systems that have previously been computationally inaccessible. Next a detailed account of solvation structures and the nature of ion pair formation mechanisms for important metal sulfates in aqueous media are presented. Radial and spatial distribution functions calculated for several ion pair species reveal that the transition from free ions to contact ion pairs involves the loss of between one to two water molecules from the cation depending on the cation size. This is correlated with the experimental hydration numbers calculated for metal sulfate electrolyte solutions at several concentrations using density and ultrasonic velocity measurements. These experiments reveal a decrease in hydration number with an increase in concentration, which can be attributed to the formation of ion pairs. A more complex metal system is the industrially important platinum group metal (PGM) chloro-anion one. Their industrial importance relates to the search for a Green Chemistry Process for the separation of PGM chloro complexes that have been extracted from the mined ore into an acidic aqueous media. This requires a PGM separation process in water. Here an understanding of the hydration structure about the iii PGM chloro-anion complexes and the role that ammonium counter-ions play in disrupting that solvent structure when ammonium PGM salts are formed, is critical in the process design. To this end a solution force field, inclusive of the majority of PGM chloro-anion complexes (i.e. (Y)2[PtCl4]2-, (Y)2[PdCl4]2-, (Y)2[PtCl6]2-, (Y)2[PdCl6]2-, (Y)2[IrCl6]2-, (Y)2[OsCl6]2-, (Y)2[RuCl6]2-, (Y)3[IrCl6]3-, (Y)3[RhCl6]3- and (Y)3[RuCl6]3- , where Y = NH4 +) arising in acidic aqueous media, parameterised from experimental and quantum mechanically derived properties, was developed. Nanosecond atomistic molecular dynamics simulations were then performed for the PGM chloro-anion complexes. Analysis of the solvation structure using radial and spatial distribution functions revealed two distinct solvent structures corresponding to the square planar and octahedral species. The formation of ion pairs disrupts the solvent structure where the hydration shells about the bivalent hexachlorometallates are more affected compared with the trivalent hexachlorometallates and these first shell waters in turn are more affected than those in the bivalent tetrachlorometallates. Finally to inform the design of a separation process transport properties such as diffusion coefficients, ion hydration numbers and water residence times for the PGM chloro-anion complexes were calculated. It is observed that the diffusion rates of PGM chloro-anion complexes are strongly correlated to their ion hydration numbers as calculated by Voronoi tessellation of the simulation cell, such that a larger hydration shell volume results in a slower PGM chloro-anion diffusion rate.
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Wuerch, Helmuth Victor. « Diagenesis and Water Chemistry of the Woodbine Group in the East Texas Basin ». DigitalCommons@USU, 1986. https://digitalcommons.usu.edu/etd/6685.
Texte intégralRésumé :
Petrographic and SEM study of flu vial-deltaic sections of the Woodbine Group in the East Texas Basin indicates that authigenic mineral suites are controlled, in part, by the presence of organic-rich matrix.
During early, precompaction diagenesis, organic matter supplied the metabolic fuel required by sulfate-reducing bacteria to reduce sulfate in depositional waters ultimately to pyrite. With burial the sulfate supply was ultimately exhausted, and bicarbonate activity thereafter controlled the precipitation of siderite and Fe-calcite.
Matrix material supplied the components and reaction sites for the most import ant porosity-occluding reaction: kaolinite --> Fe,M g chlorite. Matrix physically inhibited the growth of quartz overgrowths, yet, through compaction and as a product of the above reaction, provided a supply of silica for quartz cementation. Dissolution of salt dome cap rock has played a minor role in the cementation of the Woodbine in the East Texas Basin. Pore-filling calcite, barite, and pyrite were observed in the Woodbine where the Woodbine is in direct hydraulic communication with salt dome cap rock.
In the deep, central portion of the basin Na-Cl brine resulting from salt-dome dissolution is evolving toward a Na-Ca(Mg)-Cl brine. The evolution of the brine chemistry may be the result of cation exchange on clay minerals, albitization of plagioclase feldspars, or the dissolution of magnesium - and calcium- chloride-rich phases. The present study could not confirm any of these reactions.
WATEQF was used to calculate mineral-saturation states in Woodbine waters. Program output appears to represent accurately in situ individual mineral-saturation states at measured pH, as confirmed by petrographic and SEM identification of authigenic minerals. Relative stability between mineral pairs can be tested with thermodynamically-derived activity diagrams for the mineral pairs.
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Abdellatif, Mohamed Moustafa. « Poly(arylene ether)s with Truly Pendant Benzene Sulfonic Acid Groups ». Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1222544981.
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Mulwanda, James. « Recovery of dissolved platinum group metals from a pregnant copper sulphate leach solution by precipitation ». Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86538.
Texte intégralRésumé :
Thesis (MEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: In Base Metal Refineries (BMRs), the copper sulphate leach solution produced during the final pressure leaching stage contains impurities such as selenium and tellurium, as well as other precious metals (OPMs, namely Rh, Ru, and Ir). Se and Te are removed by precipitation with sulphur dioxide prior to electrowinning of Cu. While a small percentage of the dissolved OPMs precipitate with the Se and Te, the largest portion remains in solution and is recycled to the first stage leach. If a larger portion of the OPMs in solution can be recovered in the Se/Te precipitation stage, OPM losses and the OPM inventory of the plant can be reduced. The aim of this project was to determine operating conditions that would allow maximum OPM recovery with minimal Cu and Ni co-precipitation in the Se/Te removal section of a BMR. The effects that the operating temperature, pressure, stirring rate, reagent type, and reagent quantity have on the metal precipitation behavior and precipitate characteristics were determined experimentally. Thio-urea and sulphurous acid were evaluated as precipitation reagents for temperatures of 80°C and 160°C, stirring rates of 250 rpm and 500 rpm, and pressures equal to ambient pressure and 7 bar. 200 % and 320 % excess thio-urea and 720 % and 960 % excess sulphur dioxide were used. The precipitation of OPMs with sulphur dioxide was generally poor; the maximum percentage Rh, Ru, and Ir precipitated were 35 %, 18 %, and 20 %, respectively. It was, however, found that the OPM precipitation increased as the reagent amount was increased. Increasing the temperature further increased Rh and Ir precipitation but affected the Ru precipitation negatively. Thio-urea precipitated virtually all of the Rh contained in the solution irrespective of the values of the process variables studied. As was the case with sulphur dioxide, increasing the amount of thio-urea added resulted in increased Ru and Ir precipitation, while higher temperatures favored Ir precipitation but not Ru precipitation. The maximum percentage Ru and Ir precipitation achieved with thio-urea were 87 % and 60 %, respectively. Complete Se precipitation was observed at all process conditions, while Te precipitation increased as the operating temperature and the reagent quantity were increased. Maximum Te precipitation of 98 % and 90 % were achieved when using 320 % excess thio-urea and 960 % sulphurous acid quantities, respectively, at 160°C and a stirring rate of 250 rpm. Increasing the reagent quantity and temperature did, however, also result in increased copper and nickel precipitation. The statistical analysis of the results allowed regression models to be fitted to predict the percentage metal precipitation as a function of the investigated process variables. These models were used to define an objective function to determine the optimal operating conditions. A temperature of 80oC, a pressure of 7 bar, and 200 % excess thio-urea were proposed as the optimum operating conditions that would yield 98 % Rh, 75 % Ru, and 48 % Ir precipitation with less than 5 % Cu and Ni co-precipitation. Experimental validation tests confirmed the model predicted values and proved repeatability of the experimental data.
AFRIKAANSE OPSOMMING: Die kopersulfaat logingsoplossing wat tydens die finale drukloging stadium in Basis Metaal Raffinaderye (BMRe) produseer word, bevat onsuiwerhede soos selenium en tellurium sowel as ander edelmetale (AEMe, naamlik Rh, Ru, en Ir). Se en Te word voor Cu elektrowinning verwyder deur middel van presipitasie met swaweldioksied. Alhoewel ʼn klein persentasie van die opgeloste AEMe saam met die Se en Te presipiteer, bly die grootste gedeelte in oplossing en word gevolglik na die eerste loging stadium hersirkuleer. AEM verliese en die AEM inventaris van die aanleg kan verminder word indien ʼn groter gedeelte van die AEMe in die Se/Te presipitasie stadium herwin kan word. Die doel van hierdie projek was om bedryfstoestande te bepaal om maksimum AEM herwinning met minimale Cu en Ni kopresipitasie in die Se/Te verwyderingseksie van ʼn BMR te behaal. Die effekte wat bedryfstoestande soos temperatuur, druk, roerder tempo, tipe reagens, en hoeveelheid reagens op die metaal presipitasiegedrag en presipitaat eienskappe het, is eksperimenteel bepaal. Tio-ureum en swaweligsuur is evalueer as presipitasie reagense vir temperature van 80°C en 160°C, roerder tempo’s van 250 rpm en 500 rpm, en drukke gelyk aan omgewingsdruk en 7 bar. 200 % en 320 % oormaat tio-ureum en 720 % en 960 % oormaat swaweldioksied is gebruik. Die presipitasie van AEMe met swaweldioksied was swak in die algemeen; die maksimum persentasie Rh, Ru, en Ir presipitasie wat behaal is, is 35 %, 18 %, en 20 %, onderskeidelik. Daar is egter gevind dat die AEM presipitasie toeneem indien die hoeveelheid reagens toeneem. ʼn Toename in die temperatuur het verder tot ʼn toename in Rh en Ir presipitasie gelei, maar dit het Ru presipitasie negatief affekteer. Tio-ureum het basies al die Rh in oplossing laat presipiteer, ongeag die waardes van die ander prosesveranderlikes wat ondersoek is. Soos wat die geval vir swaweldioksied was, het ʼn toename in die hoeveelheid tio-ureum ʼn toename in die Ru en Ir presipitasie tot gevolg gehad, terwyl hoër temperature Ir presipitasie bevoordeel en Ru presipitasie benadeel het. Die maksimum persentasie Ru en Ir presipitasie wat met tio-ureum behaal is, is 87 % en 60 %, onderskeidelik. Volledige Se presipitasie is by alle proses toestande waargeneem, terwyl Te presipitasie toegeneem het soos wat die temperatuur en die hoeveelheid reagens toegeneem het. Maksimum Te presipitasie van 98 % en 90 % is behaal toe 320 % oormaat tio-ureum en 960 % oormaat swaweligsuur, onderskeidelik, by 160°C en ʼn roerder tempo van 250 rpm gebruik is. ʼn Toename in die hoeveelheid reagens en die temperatuur het egter ook meer koper en nikkel presipitasie tot gevolg gehad. Die statistiese analise van die resultate het dit moontlik gemaak om regressie modelle te pas om die persentasie metaal presipitasie as ʼn funksie van die ondersoekte veranderlikes te voorspel. Hierdie modelle is gebruik om ʼn doelfunksie te definieer ten einde die optimale bedryfstoestande te bepaal. ʼn Temperatuur van 80°C, ʼn druk van 7 bar, en 200 % oormaat tioureum is voorgestel as die optimale bedryfstoestande wat 98 % Rh, 75 % Ru, en 48 % Ir presipitasie met minder as 5 % Cu en Ni kopresipitasie tot gevolg sal hê. Eksperimentele geldigheidsbepalingtoetse het die waardes wat deur die modelle voorspel is bevestig en die herhaalbaarheid van die eksperimentele data bewys.
Livres sur le sujet "Sulfate groups"
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Motov, David Lazarevich. FLUORIC, SULFATIC and FLUOROSULFATIC COMPOUNDS of GROUP IV ELEMENTS : FORMING & PROPERTIES. St. Petersburg : Nauka, 2009.
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Godneva, Marii︠a︡ Moiseevna. Khimii︠a︡ podgruppy titana : Sulʹfaty, ftoridy, ftorosulʹfaty iz vodnykh sred. Moskva : Nauka, 2006.
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Motov, David Lazarevich. Fiziko-khimii︠a︡ i sulʹfatnai︠a︡ tekhnologii︠a︡ titano-redkometallʹnogo syrʹi︠a︡ = Physico-chemistry and sulphate technology of titanium-rare metal raw materials. Apatity : Institut khimii i tekhnologii redkikh ėlementov i mineralʹnogo syrʹi︠a︡ im. I.V. Tananaeva KNT︠S︡ RAN, 2002.
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Group, Thaumasite Expert. The thaumasite form of sulfate attack : Risks, diagnosis, remedial works and guidance on new construction : report of the Thaumasite Expert Group. London : Department of the Environment, Transport and the Regions, 1999.
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Bill, Behymer, INEEL Oversight Program et Idaho National Engineering and Environmental Laboratory., dir. Concentrations of chloride, nitrate, sulfate, and tritium in the Snake River Plain Aquifer at the Idaho National Engineering and Environmental Laboratory, Idaho, 1949 to 1996. [Boise, Idaho] : State of Idaho INEEL Oversight Program, 1999.
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Gwin, Janice L. Effect of ionizable surface groups on the adsorption of linear alkyl sulfates on polystyrene latex surfaces. 1988.
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7
Isbell, R. Australian Soil Classification. CSIRO Publishing, 2016. http://dx.doi.org/10.1071/9781486304646.
Texte intégralRésumé :
The Australian Soil Classification provides a framework for organising knowledge about Australian soils by allocating soils to classes via a key. Since its publication in 1996, this book has been widely adopted and formally endorsed as the official national system. It has provided a means of communication among scientists and land managers and has proven to be of particular value in land resource survey and research programs, environmental studies and education.
Classification is a basic requirement of all science and needs to be periodically revised as knowledge increases. This Second Edition of The Australian Soil Classification includes updates from a working group of the National Committee on Soil and Terrain (NCST), especially in regards to new knowledge about acid sulfate soils (sulfidic materials). Modifications include expanding the classification to incorporate different kinds of sulfidic materials, the introduction of subaqueous soils as well as new Vertosol subgroups, new Hydrosol family criteria and the consistent use of the term reticulate. All soil orders except for Ferrosols and Sodosols are affected by the changes.
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(Editor), M. D. Prendergast, et M. J. Jones (Editor), dir. Magmatic Sulphides-The Zimbabwe Volume. Inst of Mining & Metallurgy, 1989.
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9
Frawley, Geoff. Mucopolysaccharidoses. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199764495.003.0064.
Texte intégralRésumé :
The mucopolysaccharidoses (MPS) are a group of seven chronic progressive diseases caused by deficiencies of 11 different lysosomal enzymes required for the catabolism of glycosaminoglycans (GAGs). Hurler syndrome (MPS IH) is an autosomal recessive storage disorder caused by a deficiency of α-L-iduronidase. Hunter syndrome (MPS II) is an X-linked recessive disorder of metabolism involving the enzyme iduronate-2-sulfatase. Many of the MPS clinical manifestations have potential anesthetic implications. Significant airway issues are particularly common due to thickening of the soft tissues, enlarged tongue, short immobile neck, and limited mobility of the cervical spine and temporomandibular joints. Spinal deformities, hepatosplenomegaly, airway granulomatous tissue, and recurrent lung infections may inhibit pulmonary function. Odontoid dysplasia and radiographic subluxation of C1 on C2 is common and may cause anterior dislocation of the atlas and spinal cord compression.
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Li, Chusi. A quantitative model for the formation of sulfide ores at Sudbury and a study on the distributions of platinum-group elements in the strathcona copper-rich zones, Sudbury, Ontario. 1993.
Trouver le texte intégralChapitres de livres sur le sujet "Sulfate groups"
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Westerduin, Peter, et Constant A. A. van Boeckel. « Synthesis of Newmyo-Inositol Derivatives Containing Phosphate, Sulfate, and Sulfonamido Groups ». Dans ACS Symposium Series, 111–21. Washington, DC : American Chemical Society, 1991. http://dx.doi.org/10.1021/bk-1991-0463.ch008.
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Ranalli, Giancarlo, et Elisabetta Zanardini. « The Role of Microorganisms in the Removal of Nitrates and Sulfates on Artistic Stoneworks ». Dans Microorganisms in the Deterioration and Preservation of Cultural Heritage, 263–79. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69411-1_12.
Texte intégralRésumé :
AbstractThis chapter will focus on the role of microorganisms in the removal of nitrates and sulfates on artistic stoneworks. The main groups of microbes and their metabolisms involved in bioremoval methods for the preservation and protection of cultural artifacts are reported. The aim is to offer a comprehensive view on the role and potentiality of virtuous microorganisms in the biocleaning and bioremoval of black crusts and salts altering CH stoneworks. We highlight the importance of the use of the selected microorganisms and the adoption of adequate carriers for the anaerobic metabolism of nitrate and sulfate reducers to be applied on the altered stone surfaces. The following characteristics of the delivery system are of great importance: the ability to guarantee water content for microbes, the absence of toxicity for the environment, no negative effects to the stone surfaces, easy to prepare, to apply, and to remove from different stone surfaces at the end of the treatment. We report an overview of the last 30 years on the biocleaning processes including diagnostic studies of the alterations, the assessment of associated risks, the effectiveness and efficacy of the proposed method, and the evaluation in terms of economic and environmental sustainability.
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Naldrett, Anthony J. « Platinum group element (PGE) deposits ». Dans Magmatic Sulfide Deposits, 481–612. Berlin, Heidelberg : Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-08444-1_9.
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Beatson, R. P. « Determination of Sulfonate Groups and Total Sulfur ». Dans Methods in Lignin Chemistry, 473–84. Berlin, Heidelberg : Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-74065-7_33.
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Möller, Martin, Jürgen Omeis et Elke Mühleisen. « Association and Gelation of Polystyrenes via Terminal Sulfonate Groups ». Dans Reversible Polymeric Gels and Related Systems, 87–106. Washington, DC : American Chemical Society, 1987. http://dx.doi.org/10.1021/bk-1987-0350.ch007.
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Christen, Dines. « Molecular constants of PtS X0+ platinum sulfide ». Dans Landolt-Börnstein - Group II Molecules and Radicals, 832–35. Berlin, Heidelberg : Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-62327-5_258.
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Christen, Dines. « Molecular constants of RhS X4Σ– rhodium sulfide ». Dans Landolt-Börnstein - Group II Molecules and Radicals, 837–38. Berlin, Heidelberg : Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-62327-5_260.
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Christen, Dines. « Molecular constants of STi X3Δ titanium sulfide ». Dans Landolt-Börnstein - Group II Molecules and Radicals, 855–59. Berlin, Heidelberg : Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-62327-5_265.
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Christen, Dines. « Molecular constants of NiS X3Σg– nickel sulfide ». Dans Landolt-Börnstein - Group II Molecules and Radicals, 637–39. Berlin, Heidelberg : Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-62327-5_192.
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Christen, Dines. « Molecular constants of STa X2Δ tantalum sulfide ». Dans Landolt-Börnstein - Group II Molecules and Radicals, 848–52. Berlin, Heidelberg : Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-62327-5_263.
Texte intégralActes de conférences sur le sujet "Sulfate groups"
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Casu, B., L. Marchese, A. Naggi, G. Torri, J. Fareed, A. Racanelli et J. M. Walenga. « INFLUENCE OF THE SULFATION PATTERN ON CERTAIN BIOLOGICAL PROPERTIES OF GALACTOSAMINOGLYCANS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643251.
Texte intégralRésumé :
In order to investigate the influence of charge distribution and chain length on the biological properties of sulfated polysaccharides, additional sulfate groups were introduced into the galactosaminoglycans, chondriotin sulfate and dermatan sulfate. Using a flexible method (with sulfuric acid and chlorosulfonic acid) for concurrent sulfation and controlled depolymerization, numerous products were obtained and characterized by chemical, enzymatic and nuclear magnetic resonance spectroscopic methods. The biologic actions of these products were profiled in both in vitro and in vivo assays for antithrombotic activity. Despite a weaker in vitro anticoagulant activity, low molecular weight over sulfated galactosaminoglycans produced significant dose-dependent antithrombotic actions in animal models which were similar to the actions observed with oversulfated low molecular weight heparins. These results suggest that a significant antithrombotic activity can be elicited through non-specific interactions of polysulfates with cellular and plasma components, and that clusters of sulfate groups such as the 4-6 disulfate group on D-galactosaminoglycan residues may be important for these interactions. Furthermore, these results, also suggest that supersulfation of glycosaminogly-cans results in products with biologic activity distinct from the native material.
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Mardiguian, J., M. Corgier et M. Jouany. « STRUCTURE ACTIVITY RELATIONSHIPS OF DERMATAN SULFATE : EFFECT OF MOLECULAR SIZE AND CARBOXYL GROUP ESTERIFICATION ON HEPARIN C0FACT0R-II ACTIVATION ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644354.
Texte intégralRésumé :
Dermatan is a high molecular weight glycosaminoglycan which has been shown to enhance the inhibition of thrombin by heparin-cofactor II. The aim of this study was to establish the influence of the molecular size and the role of the carboxyl group on the in vitro activity of Dermatan Sulfate. Pig skin Dermatan Sulfate was fractionated according to molecular size by gel-chromatography on Ultrogel Ac 44. Each fraction was characterized by its sulfur content and by its mean molecular weight measured on a TSK - 4000 column in reference to standard heparin fractions. Methyl esters of the unfractionated Dermatan Sulfate with varying degree of esterification, where prepared via activation of the carboxyl groups with a carbodiimide and reaction with methanol. The results of this study show that the heparin - cofactor II mediated anti-thrombin activity of Dermatan Sulfate is increasing with the molecular weight and is abolished by esterification of the carboxyl groups. Moreover, it can be speculated that each fraction contains the same amount of high affinity fraction and that, like heparin, the potency of the high affinity component is increasing with the molecular weight.
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Eldor, A., M. Bar-Ner, L. Wasserman, Y. matzner, Z. Fuks et I. Viodavsky. « HEPARIN AND NON-ANTICOAGULANT HEPARINS INHIBIT HEPARANASE ACTIVITY IN NORMAL AND MALIGNANT CELLS:POSSIBLE THERAPEUTIC USE IN PREVENTION OF EXTRAVASATION AND DISSEMINATION OF BLOOD BORNE CELLS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643664.
Texte intégralRésumé :
Degradation of vascular subendothelium occurs in_vivo during the process of inflammation and tumor invasion. Various observations suggest that the capacity of some blood-borne cells to extravasate may depend in part on their ability to express hepara-nase activity. Incubation of human platelets, human nc-utrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase mediated release of labeled heparan sulfate cleavage fragments (0.5<Kav<0.85 on Sepharose 5B) (J. Clin.Invest. 74: 1842 and 76: 1306; Cancer Res. 43: 2704). The present study was undertaken to test the heparanase inhibitory effect of heparin and non-anticoagulant species of heparin that might havea potential therapeutic use in preventing heparanase mediated extravasation ofblood-borne cells. We prepared totallyor N-desulfated heparins which were either left with their N-position exposed or were subsequently N-acetylated or N-resulfated. These heparins exhibited less than 5% of the anticoagulant activityof native heparin. It was found that total desulfation of heparin abolished its heparanase inhibitory activity whether desulfation was followed by N-acetylation or not. Inhibitory effect was restored by resulfation of the N-position. When only the N-sulfate group was desulfated, inhibitory activity was lost but could be restored by acetylation of the N-position. These results indicate that N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the 0-sulfate groups are retained. Low Mr heparins (main Mr species of 2500 and 4500 daltons) and heparin fragments as small as the tetrasaccharide inhibited degradation of heparan sulfate in the ECM, albeit to a lower extent than native heparin. Similar effects of the different heparins were observed with heparanase activities from platelets, neutrophils and lymphoma cells. Preliminary in vivo experiments suggest that non-anticoagulant heparins interfere with tumor metastasis and experimental autoimmune diseases (some heparins were kindly provided by Inst. Choay, Paris and Kabi Vitrum, Stockholm).
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Petitou, M., J. C. Lormeau et J. Choay. « AT III BINDING SITE OF HEPARIN. DETERMINATION OF THE ROLE OF SULFATE GROUPS AT THE REDUCING-END DISACCHARIDE THROUGH NEW SYNTHETIC PENTASACCHARIDES ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642826.
Texte intégralRésumé :
A unique sequence is required in heparin for binding to antithrombin III (AT III) and eliciting anti-factor Xa activity. We have previously synthesized a pentasaccharide containing all the structural features of this sequence. It binds to AT III with the same affinity as high affinity heparin. The complex thus formed has a high anti-factor Xa activity. We have now synthesized a new series of α-methylated pentasaccharides which better mimic the naturally occurring configuration at C1 of the reducing-end glucosamine unit. The synthesis of the inactive pentasaccharide II allowed us to confirm in this series the essential role of the 3-sulfate group borne by glucosamine unit F. Wehave also particularly addressed the still unanswered question regarding the role of the 2-sulfate group borne by iduronic acid G and of the 6-sulfate group borne by glucosamine unit H. Pentasaccharides III and IV elicit the same anti-factor Xa activity which is substantially decreased as compared to I. A similar decrease has been recently reported for pentasaccharide V (T. Beetz & C.A.A. van Boeckel, Tetrahedron Lett., 1986, 27, 5889). We therefore conclude that the presence of both these sin fate groups is required for full expression of the antifactor Xa activity.
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Morani, A., F. Gianese et P. Bianchini. « KINETICS OF EXPERIMENTAL ANTITHROMBOTIC ACTIVITY OF MF 701 DERMATAN SULFATE ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643244.
Texte intégralRésumé :
In order to evaluate the intensity and duration of the prophylactic activity of dermatan sulfate against thrombosis induced by ligature of the inferior vena cava (Reyers'model), we treated 6 groups of rats at increasing intervals of time before ligature (1 min, 30 min, 45 min, 2 h, 16 h). Within each group the rats were injected subcutaneously with saline solution (controls) or increasing doses (2.5, 5, 10 and 20 mg/kg) of MF 701, dermatan sulfate (Mediolanum Farmaceutici, Milan, Italy). Two hours after ligature the presence of thrombi and their weight were recorded.A significant, dose-dependent antithrombotic effect was observed for all the treatment times. The maximum effect occured when the compound was administered 45 min before ligature (total abolition of thrombosis at the dose of 5 or more mg/kg). Total inhibition was also observed at 2 h (with 10 mg/kg) and at 4 h (with the same dose). A significant antithrombotic effect, over 50% com pared with the controls, was still found at 16 h at the dose of 20 mg/kg.These results confirm the experimental antithrombotic efficacy of dermatan sulfate already reported in a different animal model by F. Fernandez et al. (Br J. Haematol. 64, 309, 1986) and demonstrate the long duration of the prophylactic effect of the compound.
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Ihekoronye, Kingsley Kelechi, Hussein Mohammed et Pius Chukwuebuka Onuorah. « Application of Sodium Lauryl Sulfate for Enhanced Oil Recovery of Medium Crude Oil in the Niger Delta Fields ». Dans SPE Nigeria Annual International Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/211978-ms.
Texte intégralRésumé :
Abstract This research work focuses on the performance of sodium lauryl sulfate as surfactant in enhanced oil recovery of medium crude oil in the Niger Delta fields. Characterization of the sodium lauryl sulfate (surfactant) was carried out to determine the functional groups and morphology of the sample. Different tests such as interfacial tension reduction and adsorption test were conducted to evaluate the effectiveness of the sample in enhanced oil recovery. Core-flooding experiment was performed using the sample to determine the potency of sodium lauryl sulfate in enhanced oil recovery process. The results from this work showed that incremental oil recoveries of 47.8 %, 54.6 % and 56.1 % using Berea core sample (C1F) and 49.3 %, 57.6 % and 58.5 % for core sample (C2F) was observed. The results showed that sodium lauryl sulfate achieve macroscopic sweep displacement efficiency via interfacial tension reduction between the surfactant slugs and the trapped oil which helps to improve oil production.
7
Aydar, S., S. Alataş, L. Numanoğlu et A. Sönmezdağ. « EFFECT OF ORAL ANTICOAGULANTS ON STABLE ROSETTE FORMATION ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643271.
Texte intégralRésumé :
Human peripheral blood T lymphacytes when cultered in the presence of mitogen Phytohemogglutinin (PHA) acquire the capacity to form E rosettes with sheep erythrocytes that are resistant to incubation at 37° C. Whereas human thymus lymphocytes form 37° C stable E rosettes. On the other hand, it is shown that the use of anticoagulants can prevent cancer metastases which brings forth the importance of explaining the relationship between the lymphocyte functions and anticoagulant action mecha-nismus. In order to investigate this relationship, we did a group af experiments with lymphocytes of normal children and of children with severe burn wounds. Peripheral blood lymphocytes were seperated by “Lymphoprep” centrifugation technique. The lymphocytes of normal children and patients with burn were divided in two groups: A-Activated lymphocytes: 1×106 /ml lymphocytes were cultured and activated by PHAfor 48 hours at 37° C in RPMI 1640. B-Non activated lymphocytes were in culture witout PHA. 1×10™6 M/ml warfarin sulfate was added to some of the cultures of each group prior to the culture conditions. At the end of the 48 hour incubation, heat stable rosette formation was determined by the method of Wauve and co-workers. Significantly elevated levels of heat stable rosette forming cells were found in the PHA activated culture treated with warfarin sulfate in normals and patients with burn. Although the blastic transformation of T lymphocytes was found to be depressed, heat stable rosette formation of warfarin sulfate treated lymphocytes abtained from burn patients was observed to be significantly elevated. It is concluded that warfarin sulfate increases the activity of T lymphocytes by interfering with the resynthesis of heai stable E receptors.
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Choay, J., M. Petitou, B. Perly, B. Casu, M. Ragazzi et D. Ferro. « MOLECULAR CONFORMATION OF THE PENTASACCHARIDE CORRESPONDING TO THE BINDING SITE OF HEPARIN TO ANTITHROMBIN III ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642828.
Texte intégralRésumé :
The knowledge of the tridimensional structure of the sequence required in heparin for binding to anti thrombin III (AT) is essential for the understanding of the molecular basis of the anticoagulant and antithrombotic activity of this glycosamino-glycan. This problem was approached by a combined experimental (chemical synthesis and Nuclear Magnetic Resonance, "NMR") and theoretical (force field calculations) study of the pentasaccharide I reproducing the minimal sequence for high affinity binding to AT.NMR data (interproton coupling constants and nuclear-Over-hauser-enhancement) were used to test a number of possible conformation of I proposed on the basis of-molecular energy calculation. In particular, these studies, confirming the results obtained by force field calculations, showed that the sulfated iduronic residue (Is) conformation is an equilibrium between the chair 4C4 and the skew boat2S0, and permitted to discard models with the Is residue in the alternate chair 4C1. It is of interest that the relative population of the 4C4 and 2S0 conformers of IS in sequence I (40:60) is reversed with respect to that found for the same residue in the regular sequences of heparin (60:40), such a reversal being largely associated with electrostatic interactions caused by the unique 3-0-sulfo group ot the preceding amino sugar residue. The most favoured models of I are characterized by a cluster of anionic groups including all the sulfate groups proposed as essential for full expression of the activity (full line square on the formula) but one (dotted line square on the formula), plus the carboxylate group of the glucuronic acid residue.
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Alsakkaf, Sarah, Sahar Al-Dosary, Hesham El-Komy et Mona Al. Ahmadi. « Effect of Different Nanoparticles Silver, Iron Oxide and Titanium Oxide to Control Corrosion by Desulfovibrio Sp.Isolated from Oil Fields ». Dans International Petroleum Technology Conference. IPTC, 2022. http://dx.doi.org/10.2523/iptc-22588-ms.
Texte intégralRésumé :
Abstract Microbiologically influenced corrosion (MIC), or biocorrosion is a corrosion of metals in environment containing microorganism. The microorganisms can initiate corrosion or accelerate by their metabolic activities. Recently, MIC problems common in oil recovery which depend on seawater injection. Many of researchers have been investigated that Sulfate-reducing bacteria (SRB) is the major groups of microorganisms that cause corrosion. Pitting corrosion and sulfide generation in oil and gas fields are correlated to presence of SRB. Last decade, nanotechnology is alternative biocide of chlorine-free. Metal nanoparticles improve the antimicrobial activity of the metals. The biocidal activity of AgNPs, Fe2O3NPs and TiO2NPs against Desulfovibrio sp. (St.7) at 1 ppm, 50 ppm and 100 ppm concentrations as estimated by cell growth and H2S production was examined. AgNPs and Fe2O3NPs had no significant effect at a low concentration, 1 ppm, on both bacterial growth and sulfide production. Whereas, increasing NPs concentration to 50 ppm and 100 ppm led to a complete inhibition of both growth and sulfide production. TiO2NPs gave complete inhibitory effect on both growth and H2S production by Desulfovibrio sp. (St.7) at all the tested concentrations (1ppm, 50ppm, 100ppm). The study supports the use of such nanoparticles as a green biocide and safe method to control corrosion problem caused by sulphate reducing bacteria.
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Kim, Ki Young, Ki-Taek Byun et Ho-Young Kwak. « The Mesoscopic Simulation on the Structures of the Surfactant Solution Using Dissipative Particle Dynamics ». Dans ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80702.
Texte intégralRésumé :
With a simple model of surfactant which consists of hydrophilic head group and hydrophobic tail groups connected by harmonic springs, structural change of the association structures of surfactant in an aqueous solution was studied using the dissipative particle dynamics (DPD) simulation. The effect of the hydrophilic interaction between the head and water molecules and the hydrophobic interaction between the tail and water molecules and the head and tail on the structural change of the association structures was studied. Simulations show that proper value of these interaction parameters could yield desirable change of the association structure depending on the concentration of the surfactant. For example, a hexagonal structure appears when the volume fraction of surfactant of SDS (sodium dodecyl sulfate) becomes 25% in aqueous solution, which is in good agreement with observation.
Rapports d'organisations sur le sujet "Sulfate groups"
1
Gadd, M. G., J. M. Peter et D. Layton-Matthews. Genesis of hyper-enriched black shale Ni-Mo-Zn-Pt-Pd-Re mineralization in the northern Canadian Cordillera. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/328013.
Texte intégralRésumé :
Polymetallic (Ni-Mo-Zn-Pt-Pd-Au-Re) hyper-enriched black shales in the northern Canadian Cordillera consist of thin, semi-massive sulfides interbedded with black shale. We studied HEBS deposits at Nick, Peel River, Monster River, and Moss in northern Yukon, and at a single locality underlying the Cardiac Creek Pb-Zn-Ag deposit in northeastern British Columbia. High-grade mineralization contains up to 7.4 weight per cent Ni, 2.7 weight per cent Zn, 0.38 weight per cent Mo, 400 ppb Pt, 250 ppb Pd, 160 ppb Au, and 58.5 ppm Re. Sulfide mineralization formed during syngenesis to later diagenesis. Analyses by LA-ICP-MS indicate that pyrite is the principal host of platinum-group elements, Au, and Re. Mineralization and sedimentation were coeval based on the overlap between Re-Os geochronology of HEBS at Nick and Peel River (390.7 ± 5.1 and 387.3 ± 4.4 Ma, respectively) and conodont biostratigraphic ages of sedimentary host rocks. Bulk S isotope composition of HEBS is uniformly negative, indicating that bacterial reduction of seawater sulfate generated sulfur to precipitate sulfide minerals. The initial Os ratios at Peel River (0.25 ± 0.07) and Nick (0.32 ± 0.20) overlap with Middle Devonian seawater, suggesting that elemental enrichment was derived from seawater.
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Martin, P. F. C., et R. O. Lokken. Characterization of phosphate/sulfate waste grout cores. Office of Scientific and Technical Information (OSTI), septembre 1993. http://dx.doi.org/10.2172/10191613.
Texte intégral
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Kingston, A. W., O. H. Ardakani et R A Stern. Tracing the subsurface sulfur cycle using isotopic and elemental fingerprinting : from the micro to the macro scale. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329789.
Texte intégralRésumé :
Hydrogen sulfide (H2S) is a toxic and corrosive gas that commonly occurs in deeply buried sedimentary systems. Understanding its distribution is paramount to creating safe and effective models of H2S occurrence aiding in the identification of high-risk areas. Characterizing subsurface sulfur sources and H2S formation pathways would enhance these models leading to more accurate predictions of potential high H2S regions. However, gaps remain in our understanding of the dominant formation processes and migration pathways of key ingredients for H2S production in the Lower Triassic Montney Formation of the Western Canada Sedimentary Basin (WCSB). Essential to this is assessing the reactants necessary for H2S production, potential pathways for fluid migration, diagenetic history, and changes in redox conditions through time. The Montney Formation has undergone several phases of diagenesis related to post-depositional alteration and multiple cycles of tectonic burial and uplift. Early chemical alteration includes dolomitization and, in some cases, microbial reduction of porewater sulfate to sulfide that occurred prior to significant burial (Davies et al., 1997; Vaisblat et al., 2021; Liseroudi et al., 2020, 2021). The most recent tectonic-related burial during the Laramide Orogeny resulted in burial depths in excess of 3-5 km (Ness, 2001; Ducros et al., 2017) leading to significant thermal and barometric alteration. Associated with this orogenic activity was the reactivation of underlying faults (O'Connell et al., 1990) and development of fractures especially near the deformation front. These fractures provide conduits for fluid migration into the Montney that combined with heat and pressure resulting in hydrocarbon generation, migration, and development of overpressure, notably in the western margin of the basin. In addition, high temperatures resulted in thermochemical sulfate reduction (TSR) leading to the formation of H2S and subsequently pyrite. We present an interpretation of the Montney subsurface sulfur cycle through the use of petrography, micro- and macro-scale geochemical analysis (isotopic and elemental) to illustrate the complexity of this system. This work relies heavily on previous studies within and outside our research group and incorporates new analytical techniques to expand the toolbox. We aim to guide future research directions and activities by addressing issues related to sampling and data quality issues, analytical approaches, and highlight knowledge gaps.
4
Shenker, Moshe, Paul R. Bloom, Abraham Shaviv, Adina Paytan, Barbara J. Cade-Menun, Yona Chen et Jorge Tarchitzky. Fate of Phosphorus Originated from Treated Wastewater and Biosolids in Soils : Speciation, Transport, and Accumulation. United States Department of Agriculture, juin 2011. http://dx.doi.org/10.32747/2011.7697103.bard.
Texte intégralRésumé :
Beneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levelsBeneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levels that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction.
5
Serne, R. J., W. J. Martin, V. L. LeGore, C. W. Lindenmeier, S. B. McLaurine, P. F. C. Martin et R. O. Lokken. Leach tests on grouts made with actual and trace metal-spiked synthetic phosphate/sulfate waste. Office of Scientific and Technical Information (OSTI), octobre 1989. http://dx.doi.org/10.2172/5391748.
Texte intégral
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Sams, T. L., E. W. McDaniel, O. K. Tallent, C. L. Francis et F. A. Washburn. Formulation studies and grout development for fixation of variable phosphate/sulfate waste, Milestone 195. Office of Scientific and Technical Information (OSTI), février 1988. http://dx.doi.org/10.2172/5196817.
Texte intégral
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Serne, R. J., W. J. Martin, S. B. McLaurine, S. P. Airhart, V. L. LeGore et R. L. Treat. Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment. Office of Scientific and Technical Information (OSTI), décembre 1987. http://dx.doi.org/10.2172/5534671.
Texte intégral
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Langton, C., et D. Stefanko. BLENDED CALCIUM ALUMINATE-CALCIUM SULFATE CEMENT-BASED GROUT FOR P-REACTOR VESSEL IN-SITU DECOMMISSIONING. Office of Scientific and Technical Information (OSTI), mars 2011. http://dx.doi.org/10.2172/1011327.
Texte intégral
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Evans, D. T. W., et B. F. Kean. Geology of the Jacks Pond Volcanogenic Sulfide Prospects, Victoria Lake Group, Central Newfoundland. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1986. http://dx.doi.org/10.4095/121083.
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Bosse, J., S. Paradis et M. Gauthier. L'amas sulfure de champagne : un gîte exhalatif dans les argilites Ordoviciennes du groupe de Magog, Appalaches du Québec. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1991. http://dx.doi.org/10.4095/132594.
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