Interaction of chelating agents with cadmium in mice and rats

International Nuclear Information System (INIS)

Eybl, V.; Sykora, J.; Koutensky, J.; Caisova, D.; Schwartz, A.; Mertl, F.

1984-01-01

The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl 2 and on the whole body retention and tissue distribution of cadmium after the IV application of /sup 115mCdCl 2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatement of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl 2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of /sup 115m/Cd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes

Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

International Nuclear Information System (INIS)

Hunt, F.C.; Maddalena, D.J.

1982-01-01

The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo. (U.K.)

Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

International Nuclear Information System (INIS)

Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K.

1996-03-01

The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates

Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

Energy Technology Data Exchange (ETDEWEB)

Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K. [Pacific Northwest National Lab., Richland, WA (United States)

1996-03-01

The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates.

Interaction of chelating agents with cadmium in mice and rats.

Science.gov (United States)

Eybl, V; Sýkora, J; Koutenský, J; Caisová, D; Schwartz, A; Mertl, F

1984-01-01

The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl2 and on the whole body retention and tissue distribution of cadmium after the IV application of 115mCdCl2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatment of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination of the retention and distribution of Cd in mice, it was demonstrated that the combined application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of 115mCd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes. PMID:6734561

On-load chelating agent treatments for conventional and nuclear power stations

International Nuclear Information System (INIS)

Turner, D.J.

1978-01-01

The paper is concerned with the application of on-load chelating agent treatments to those types of water circuit for which they are not currently available: high pressure drum boilers, sub-critical once-through boilers and water reactors. An attempt was made to see whether the most thermally stable types of chelating agent are likely to be sufficiently strong chelating agents either to dissolve established Fe 3 O 4 deposits or to prevent their precipitation from solution. It seems likely that they are strong enough to prevent Fe 3 O 4 depositing in a once-through boiler, through some may require that mildly reducing conditions are maintained. They would not be effective in a high pressure drum boiler (at 350 0 C) unless much more strongly reducing conditions could be maintained. For such boilers it would probably be better to seek multidentate ligands of less than maximum thermal stability. There are some indications that chelating agents based on carbon chains are more stable than NTA or EDTA so that citric acid or some of the unidentified chelating agents recently found to be produced radiolytically may have potential in the treatment of high pressure drum boilers. The prospects for periodic full-load cleaning seem less good for both types of boiler. There may also be a role for radiolytically produced chelating agents in alleviating some of the problems caused by the deposition of radioactive corrosion products in water reactor circuits. The chances for successful development fall from quite good to very low down the series SGHWR moderator circuit, PWR primary circuit, ammonia dosed BWR, neutral chemistry BWR (including SGHWR). (author)

Searching for new aluminium chelating agents: a family of hydroxypyrone ligands.

Science.gov (United States)

Toso, Leonardo; Crisponi, Guido; Nurchi, Valeria M; Crespo-Alonso, Miriam; Lachowicz, Joanna I; Mansoori, Delara; Arca, Massimiliano; Santos, M Amélia; Marques, Sérgio M; Gano, Lurdes; Niclós-Gutíerrez, Juan; González-Pérez, Josefa M; Domínguez-Martín, Alicia; Choquesillo-Lazarte, Duane; Szewczuk, Zbigniew

2014-01-01

Attention is devoted to the role of chelating agents in the treatment of aluminium related diseases. In fact, in spite of the efforts that have drastically reduced the occurrence of aluminium dialysis diseases, they so far constitute a cause of great medical concern. The use of chelating agents for iron and aluminium in different clinical applications has found increasing attention in the last thirty years. With the aim of designing new chelators, we synthesized a series of kojic acid derivatives containing two kojic units joined by different linkers. A huge advantage of these molecules is that they are cheap and easy to produce. Previous works on complex formation equilibria of a first group of these ligands with iron and aluminium highlighted extremely good pMe values and gave evidence of the ability to scavenge iron from inside cells. On these bases a second set of bis-kojic ligands, whose linkers between the kojic chelating moieties are differentiated both in terms of type and size, has been designed, synthesized and characterized. The aluminium(III) complex formation equilibria studied by potentiometry, electrospray ionization mass spectroscopy (ESI-MS), quantum-mechanical calculations and (1)H NMR spectroscopy are here described and discussed, and the structural characterization of one of these new ligands is presented. The in vivo studies show that these new bis-kojic derivatives induce faster clearance from main organs as compared with the monomeric analog. © 2013.

Enhancement of 67Ga tumor-to-blood ratios by chelating agent

International Nuclear Information System (INIS)

Saji, Hideo; Yokoyama, Akira; Hata, Naotaka; Misaki, Atsushi; Tanaka, Hisashi.

1980-01-01

Chelating agent, such as, CaEDTA, CaDTPA, D-penicillamine, DMSA, desferoxamine, NTA, cysteine ethyl ester, BAL, α-MPG, phthalein complexone, were tested as a possible contrast enhancing agent for tumor imaging with 67 Ga-citrate. The intravenous administration of a chelating agent to Ehrlich's tumor bearing mice, one hour after the injection of 67 Ga-citrate, accelerated the blood clearance with only a very slight change of activity in the target, increasing the tumor-to-blood ratio, and consequently achieving a better visualization. Among the tested chelating agents, D-penicillamine showed the highest target-to-nontarget ratio at a shorter time: a good tumor-to-blood ratio, performed after 24 hr with non-treated animals, was achieved in only 1-3 hr with post-treated animals. Thus, D-penicillamine hold a considerable promise as a contrast enhancing agent for future clinical use. (author)

Decorporation of metal ions by chelating agents

International Nuclear Information System (INIS)

Koenig, T.

1978-01-01

Simple model designs to simulate the effect of therapeutical chelating agents on the behaviour of metals in mammal organisms with and without excretion have been derived and analytical solutions given for the corresponding differential equations. The possibilities of these models in the short-term description of plasma kinetics of various metals, the competition of the therapeutical ligands with proteins for the metal and of the metabolism of chelating agents were tested and the properties applying extreme conceivable parameters were analyzed. The simple models were successsively expanded in logical sequence, so that it was possible to qualitatively well describe over a long period of time, the metallic kinetics in plasma, organs and urine, the retention of the ligands and their effect on the metal excretion. Two suggestions were given to describe the so-called after-effect, an increased excretion of the metal at times when the ligand is almost completely excreted and their different behaviour after injecting the metal chelate is given. Calculations on the therapy with several ligand data as well as on dose fractionation are described resting on the ratios in the plutonium-239 chosen model parameters and the determining mechanisms analyzed. (orig./MG) [de

Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

Energy Technology Data Exchange (ETDEWEB)

Fatimah, Soja Siti, E-mail: soja-sf@upi.edu [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Bahti, Husein H.; Hastiawan, Iwan [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Permanasari, Anna [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia)

2016-02-08

The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, ({sup 1}H, and {sup 13}C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

Science.gov (United States)

Fatimah, Soja Siti; Bahti, Husein H.; Hastiawan, Iwan; Permanasari, Anna

2016-02-01

The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, (1H, and 13C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

Rates of nickel(II) capture from complexes with NTA, EDDA, and related tetradentate chelating agents by the hexadentate chelating agents EDTA and CDTA: Evidence of a "semijunctive" ligand exchange pathway

Science.gov (United States)

Boland, Nathan E.; Stone, Alan T.

2017-09-01

Many siderophores and metallophores produced by soil organisms, as well as anthropogenic chelating agent soil amendments, rely upon amine and carboxylate Lewis base groups for metal ion binding. UV-visible spectra of metal ion-chelating agent complexes are often similar and, as a consequence, whole-sample absorbance measurements are an unreliable means of monitoring the progress of exchange reactions. In the present work, we employ capillary electrophoresis to physically separate Ni(II)-tetradentate chelating agent complexes (NiL) from Ni(II)-hexadentate chelating agent complexes (NiY) prior to UV detection, such that progress of the reaction NiL + Y → NiY + L can be conveniently monitored. Rates of ligand exchange for Ni(II) are lower than for other +II transition metal ions. Ni(II) speciation in environmental media is often under kinetic rather than equilibrium control. Nitrilotriacetic acid (NTA), with three carboxylate groups all tethered to a central amine Lewis base group, ethylenediamine-N,N‧-diacetic acid (EDDA), with carboxylate-amine-amine-carboxylate groups arranged linearly, plus four structurally related compounds, are used as tetradentate chelating agents. Ethylenediaminetetraacetic acid (EDTA) and the structurally more rigid analog trans-cyclohexaneethylenediaminetetraacetic acid (CDTA) are used as hexadentate chelating agents. Effects of pH and reactant concentration are explored. Ni(II) capture by EDTA was consistently more than an order of magnitude faster than capture by CDTA, and too fast to quantify using our capillary electrophoresis-based technique. Using NiNTA as a reactant, Ni(II) capture by CDTA is independent of CDTA concentration and greatly enhanced by a proton-catalyzed pathway at low pH. Using NiEDDA as reactant, Ni(II) capture by CDTA is first order with respect to CDTA concentration, and the contribution from the proton-catalyzed pathway diminished by CDTA protonation. While the convention is to assign either a disjunctive

Study of chelating agent as a surface modifier for retarding corrosion attack on ferrous metal

International Nuclear Information System (INIS)

Nur Ubaidah Saidin; Muhamad Daud; Siti Radiah Mohd Kamarudin; Zaifol Samsu; Azali Muhamad; Rusni Rejab; Mohd Saari Ripin; Mohd Shariff Sattar

2010-01-01

A different concentration of chelating agents in electrolyte of 3.5 % NaCl was applied to bare ferrous metal and tested for their effectiveness as a corrosion retardant. The performance of the samples was measured using corrosion measurement system. The results indicated that the contribution of chelating agent was expediting the reduction of the passive film. The anodic behavior was clearly found to be influenced by the concentration of the chelating agent. It was also found that some of the corrosion was apparently converted to protective layer over a period of time. Excessive moisture caused breakdown of film by removing the unreacted chelating agent and causing regrowth of the existing rust. (author)

Multiple-heteroatom-containing sulfur compounds in a high sulfur coal

International Nuclear Information System (INIS)

Winans, R.E.; Neill, P.H.

1990-01-01

Flash vacuum pyrolysis of a high sulfur coal has been combined with high resolution mass spectrometry yielding information on aromatic sulfur compounds containing an additional heteroatom. Sulfur emission from coal utilization is a critical problem and in order to devise efficient methods for removing organic sulfur, it is important to know what types of molecules contain sulfur. A high sulfur Illinois No. 6 bituminous coal (Argonne Premium Coal Sample No. 3) was pyrolyzed on a platinum grid using a quartz probe inserted into a modified all glass heated inlet system and the products characterized by high resolution mass spectrometry (HRMS). A significant number of products were observed which contained both sulfur and an additional heteroatom. In some cases two additional heteroatoms were observed. These results are compared to those found in coal extracts and liquefaction products

A study on the adsorption and subsurface transport of radioactive solutes in the presence of chelating agents

International Nuclear Information System (INIS)

Baik, Min Hoon

1994-02-01

In this study, adsorption and transport models were developed to analyze the effect of chelating agents on the adsorption and subsurface transport of radioactive solutes. The effect of chelating agents on the adsorption of radioactive solutes was analyzed by developing an adsorption model based upon the extended concept of distribution coefficient reflecting the presence of chelating agents. Also, a batch adsorption experiment was conducted in order to validate the developed adsorption model and to investigate the effect of chelating agent on the adsorption of radioactive metal solutes. In this experiment, a Cobalt(II)/EDTA/Bentonite system was considered as a representative chelation/adsorption system. It was found from the results that the presence of chelating agents significantly reduced the adsorbing capacity of geologic media such as clay minerals and soils. Thus it was concluded that the presence of chelating agents even in a small amount could contribute to the mobilization of radioactive solutes from radioactive waste burial sites by reducing the adsorbing capacity of geologic media. The effect of chelating agents on the transport of radioactive solutes in subsurface porous media was analyzed by formulating an advective-dispersive transport model which incorporated chelate formation, adsorption, decay, and degradations and by introducing the concept of a tenad. Particularly the governing equation for the tenad of radioactive solutes, M, was presented as a linear partial differential form by introducing the extended distribution coefficient, K D . The calculated results from the model showed that the transport rate of the chelated radionuclides was much greater than that of the free ionic radionuclides. This much faster transport of the chelated radionuclides was found to be due to the lower retardation factor of the chelated radionuclides than the free ionic radionuclides. The effect of parameters on the transport of radioactive solutes was also analyzed

Studies of the competition for thorium ion between chelating agents and bovine serum albumin

International Nuclear Information System (INIS)

Luo Meichu; Zhang Meizhen; Sun Meizhen; Chen Shijie

1995-01-01

Fourteen chelation agents (polyaminopolcarboxylate type--TTHA, DTPA, EDTA; phenolicpolycarboxylate type--811, 8102, 7601, 7602, 7603, 7616, 7711, 7724, 7803, 7804, 8307) were studied their competitive ability to mobilize the thorium with bovine serum albumin (BSA). The experimental results showed that the competitive ability of TTHA, 8102, 811 to chelate Thorium with BSA were the strongest, and EDTA was the worst in all chelating agents. The measured order of the competitive ability of chelators is basically consistent with animal experimental results in vivo. The parameter F is defined as the competitive ability of chelators. F is taken as a screening criterion for de-corporate thorium which is simple, quick and effective method in vitro

AAZTA: an ideal chelating agent for the development of {sup 44}Sc PET imaging agents

Energy Technology Data Exchange (ETDEWEB)

Nagy, Gabor; Szikra, Dezso; Trencsenyi, Gyoergy [Scanomed Ltd., Debrecen (Hungary); University of Debrecen, Medical Imaging Clinic (Hungary); Fekete, Aniko [University of Debrecen, Medical Imaging Clinic (Hungary); Garai, Ildiko [Scanomed Ltd., Debrecen (Hungary); Giani, Arianna M.; Negri, Roberto [Dipartimento di Scienze del Farmaco, Universita del Piemonte Orientale, Novara (Italy); Masciocchi, Norberto [Dipartimento di Scienza e Alta Tecnologia e To.Sca.Lab, Universita degli Studi dell' Insubria, Como (Italy); Maiocchi, Alessandro; Uggeri, Fulvio [Bracco Imaging spa, Bracco Research Centre, Colleretto Giacosa (Italy); Toth, Imre [Department of Inorganic and Analytical Chemistry, University of Debrecen (Hungary); Aime, Silvio [Dipartimento di Biotecnologie Molecolari e Scienze della Salute, Centro di Imaging Molecolare e Preclinico, Universita degli Studi di Torino (Italy); Giovenzana, Giovanni B. [Dipartimento di Scienze del Farmaco, Universita del Piemonte Orientale, Novara (Italy); CAGE Chemicals srl, Novara (Italy); Baranyai, Zsolt [Bracco Imaging spa, Bracco Research Centre, Colleretto Giacosa (Italy); Department of Inorganic and Analytical Chemistry, University of Debrecen (Hungary)

2017-02-13

Unprecedented fast and efficient complexation of Sc{sup III} was demonstrated with the chelating agent AAZTA (AAZTA=1,4-bis(carboxymethyl)-6-[bis(carboxymethyl)] amino-6-methylperhydro-1,4-d iazepine) under mild experimental conditions. The robustness of the {sup 44}Sc(AAZTA){sup -} chelate and conjugated biomolecules thereof is further shown by in vivo PET imaging in healthy and tumor mice models. The new results pave the way towards development of efficient Sc-based radiopharmaceuticals using the AAZTA chelator. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Mercury removal in utility wet scrubber using a chelating agent

Science.gov (United States)

Amrhein, Gerald T.

2001-01-01

A method for capturing and reducing the mercury content of an industrial flue gas such as that produced in the combustion of a fossil fuel or solid waste adds a chelating agent, such as ethylenediaminetetraacetic acid (EDTA) or other similar compounds like HEDTA, DTPA and/or NTA, to the flue gas being scrubbed in a wet scrubber used in the industrial process. The chelating agent prevents the reduction of oxidized mercury to elemental mercury, thereby increasing the mercury removal efficiency of the wet scrubber. Exemplary tests on inlet and outlet mercury concentration in an industrial flue gas were performed without and with EDTA addition. Without EDTA, mercury removal totaled 42%. With EDTA, mercury removal increased to 71%. The invention may be readily adapted to known wet scrubber systems and it specifically provides for the removal of unwanted mercury both by supplying S.sup.2- ions to convert Hg.sup.2+ ions into mercuric sulfide (HgS) and by supplying a chelating agent to sequester other ions, including but not limited to Fe.sup.2+ ions, which could otherwise induce the unwanted reduction of Hg.sup.2+ to the form, Hg.sup.0.

Glyphosate, a chelating agent-relevant for ecological risk assessment?

Science.gov (United States)

Mertens, Martha; Höss, Sebastian; Neumann, Günter; Afzal, Joshua; Reichenbecher, Wolfram

2018-02-01

Glyphosate-based herbicides (GBHs), consisting of glyphosate and formulants, are the most frequently applied herbicides worldwide. The declared active ingredient glyphosate does not only inhibit the EPSPS but is also a chelating agent that binds macro- and micronutrients, essential for many plant processes and pathogen resistance. GBH treatment may thus impede uptake and availability of macro- and micronutrients in plants. The present study investigated whether this characteristic of glyphosate could contribute to adverse effects of GBH application in the environment and to human health. According to the results, it has not been fully elucidated whether the chelating activity of glyphosate contributes to the toxic effects on plants and potentially on plant-microorganism interactions, e.g., nitrogen fixation of leguminous plants. It is also still open whether the chelating property of glyphosate is involved in the toxic effects on organisms other than plants, described in many papers. By changing the availability of essential as well as toxic metals that are bound to soil particles, the herbicide might also impact soil life, although the occurrence of natural chelators with considerably higher chelating potentials makes an additional impact of glyphosate for most metals less likely. Further research should elucidate the role of glyphosate (and GBH) as a chelator, in particular, as this is a non-specific property potentially affecting many organisms and processes. In the process of reevaluation of glyphosate its chelating activity has hardly been discussed.

Inositol hexa-phosphate: a potential chelating agent for uranium

International Nuclear Information System (INIS)

Cebrian, D.; Tapia, A.; Real, A.; Morcillo, M.A.

2007-01-01

Chelation therapy is an optimal method to reduce the radionuclide-related risks. In the case of uranium incorporation, the treatment of choice is so far i.v infusion of a 1.4% sodium bicarbonate solution, but the efficacy has been proved to be not very high. In this study, we examine the efficacy of some substances: bicarbonate, citrate, diethylenetriamine pentaacetic acid (DTPA), ethidronate (EHBP) and inositol hexa-phosphate (phytic acid) to chelate uranium using a test developed by Braun et al. Different concentrations of phytic acid, an abundant component of plant seeds that is widely distributed in animal cells and tissues in substantial levels, were tested and compared to the same concentrations of sodium citrate, bicarbonate, EHBP and DTPA. The results showed a strong affinity of inositol hexa-phosphate for uranium, suggesting that it could be an effective chelating agent for uranium in vivo. (authors)

New method for studying the efficiency of chelating agents of the polyamine acid series for internal decontamination

International Nuclear Information System (INIS)

Lafuma, J.; Nenot, J.C.; Morin, M.

1968-01-01

We followed the biological fate of a complex formed on one side with either a rare earth (cerium-144) or a transuranium element (plutonium-239), and on the other side with a chelating agent of the polyamino acid series (EDTA, BAETA, DTPA, TTHA). This method allowed to study: 1 - the in vivo stability of the various complexes and to compare them; 2 - the stability of the complexes as a function of the isotope - chelating agent weight relationships; 3 - the metabolism of the chelating agents resulting in stable complexes, i. e. DTPA and TTHA mainly. This simple method brought out the higher efficiency, of DTPA in chelating rare earths and plutonium and for therapeutic purposes. (authors) [fr

Preparation of Ga-67 labeled monoclonal antibodies using deferoxamine as a bifunctional chelating agent

International Nuclear Information System (INIS)

Endo, K.; Furukawa, T.; Ohmomo, Y.

1984-01-01

Ga-67 labeled monoclonal IgG or F(ab')/sub 2/ fragments against α-fetoprotein and β-subunit of human choriogonadotropin (HCG), were prepared using Deferoxamine (DFO) as a bifunctional chelating agent. DFO, a well-known iron chelating agent, was conjugated with monoclonal antibodies (Ab) by a glutaraldehyde two step method and the effect of conjugation on the Ab activities was examined by RIA and Scatchard plot analysis. In both monoclonal Ab preparations, the conjugation reaction was favored as the pH increased. However, Ab-binding activities decreased as the molecular ratios of DFO to Ab increased. Preserved Ab activities were observed when Ab contained DFO per Ab molecule less than 2.1. At a ratio of over 3.3 DFO molecules per Ab, the maximal binding capacity rather than the affinity constant decreased. The inter-molecular cross linkage seemed to be responsible for the deactivation of binding activities. The obtained DFO-Ab conjugates, were then easily labeled with high efficiency and reproducibility and Ga-67 DFO-Ab complexes were highly stable both in vitro and in vivo. Thus, biodistribution of Ga-67 labeled F(ab')/sub 2/ fragments of monoclonal Ab to HCG β-subunit was attempted in nude mice transplanted with HCG-producing human teratocarcinoma. Tumor could be visualized, in spite of relatively high background imaging of liver, kidney and spleen. The use of DFO as a bifunctional chelating agent provided good evidence for its applicability to labeling monoclonal Ab with almost full retention of Ab activities. Further, availability of Ga-68 will make Ga-68 DFO-monoclonal Ab a very useful tool for positron tomography imaging of various tumors

Treating agent for urea containing radioactive materials

International Nuclear Information System (INIS)

Ogawa, Hiroshi; Maki, Kentaro.

1973-01-01

Object: To add a coagulant into urea containing radioactive material to precipitate and remove the radioactive material in the urea. Structure: Iodosalt is added into urea and next, a mixed reagent in which silver ion or silver acetic ion and iron hydroxide precipitation or ferrite ion coexist is added therein. The urea is treated to have a sufficient alkaline, after which it is introduced into a basket type centrifuge formed with a filter layer in combination of an upper glass fiber layer and a lower active carbon layer. The treating agent can uniformly remove radioactive ion and radioactive chelate within urea containing inorganic salt and various metabolites. (Nakamura, S.)

Method of processing liquid wastes containing radioactive materials

International Nuclear Information System (INIS)

Matsumoto, Kaname; Shirai, Takamori; Nemoto, Kuniyoshi; Yoshikawa, Jun; Matsuda, Takeshi.

1983-01-01

Purpose: To reduce the number of solidification products by removing, particularly, Co-60 that is difficult to remove in a radioactive liquid wastes containing a water-soluble chelating agent, by adsorbing Co-60 to a specific chelating agent. Method: Liquid wastes containing radioactive cobalt and water-soluble chelating agent are passed through the layer of less water-soluble chelating agent that forms a complex compound with cobalt in an acidic pH region. Thus, the chelating compound of radioactive cobalt (particularly Co-60) is eliminated by adsorbing the same on a specific chelating agent layer. The chelating agent having Co-60 adsorbed thereon is discarded as it is through the cement- or asphalt-solidification process, whereby the number of solidification products to be generated can significantly be suppressed. (Moriyama, K.)

Chelation Therapy for Mercury Poisoning

Directory of Open Access Journals (Sweden)

Rong Guan

2009-01-01

Full Text Available Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role of chelating agents against mercury poisoning, which provides a promising research direction for broader application of chelation therapy in prevention and treatment of mercury poisoning.

Sulfur containing nanoporous materials, nanoparticles, methods and applications

Science.gov (United States)

Archer, Lynden A.; Navaneedhakrishnan, Jayaprakash

2018-01-30

Sulfur containing nanoparticles that may be used within cathode electrodes within lithium ion batteries include in a first instance porous carbon shape materials (i.e., either nanoparticle shapes or "bulk" shapes that are subsequently ground to nanoparticle shapes) that are infused with a sulfur material. A synthetic route to these carbon and sulfur containing nanoparticles may use a template nanoparticle to form a hollow carbon shape shell, and subsequent dissolution of the template nanoparticle prior to infusion of the hollow carbon shape shell with a sulfur material. Sulfur infusion into other porous carbon shapes that are not hollow is also contemplated. A second type of sulfur containing nanoparticle includes a metal oxide material core upon which is located a shell layer that includes a vulcanized polymultiene polymer material and ion conducting polymer material. The foregoing sulfur containing nanoparticle materials provide the electrodes and lithium ion batteries with enhanced performance.

Detoxication and removal of uranium by phenolic chelating agents

International Nuclear Information System (INIS)

Luo Meichu; Chen Guibao; Li Landi

1992-01-01

The use of phenolic chelating agents for detoxication and removal of uranyl nitrate in mice and rats is reported. Antidotal test: 8102, 7601 and 811 were given 2 mM/kg subcutaneously to mice and 1 mM/kg intramuscularly to rats when the animals were injected i.p. with different doses (100-500 mg/kg) of uranyl nitrate. The results showed that the antidotal effects of 8102 and 7601 were better than 811 in augmenting survival, survival time (day) and renal factor (kidney weight/body weight x100). 8102 was superior to 7601 against higher dose of uranyl nitrate intoxication. Removal test: five phenolic chelating agents (8102, 7601, 811, 7603 and 8307) were studied in rats. The results obtained demonstrated that 8102 and 7601 were better than 811, 7603 and 8307 in increasing U excretion in the urine after acute uranyl nitrate intoxication. The effects of different doses (300-1000 μM/kg) of 8102 was superior to 7601 in increasing U excretion in the urine and decreasing U deposition in the tissues. The toxicity and dose of 8102 in treating uranium intoxication are discussed

Chelating impact assessment of biological ad chemical chelates on metal extraction from contaminated soils

International Nuclear Information System (INIS)

Manwar, S.; Iram, S.

2014-01-01

Soil contamination is the result of uncontrolled waste dumping and poor practices by humans. Of all the pollutants heavy metals are of particular concern due to their atmospheric deposition, leaching capacity and non-biodegradability. Heavy metal containing effluent is discharged into the agricultural fields and water bodies. This results in the accumulation of heavy metals in soil and the crops grown on that soil. Studies have revealed detrimental impacts on soil fertility and the poor health of animals and humans. Phytoextraction is widely researched for remediation of heavy metal contaminated soil. To enhance the effect of phytoextraction heavy metals have to be available to the plants in soluble form. In this study the potential of different chelating agents was assessed in solubilizing the heavy metals making easy for plants to uptake them. For this purpose efficient chemical and biological chelating agent had to be identified. Along with that an optimum dose and application time for chemical chelating agent was determined. Ethylenediamine tetraacetic acid (EDTA), Diethylene triamine pentaacetic acid (DTPA), Nitriloacetic acid (NTA) were applied to the soil, containing Pb, Cr, Cu and Cd, at different concentrations and application time. Aspergillus niger and Aspergillus flavus were incubated in soil for different time periods. In correspondence with findings of the study, Pb and Cr were best solubilized by 5mM EDTA. For Cd and Cu 5mM DTPA carried out efficient chelation. NTA showed relatively inadequate solubilisation, although for Cr it performed equal to EDTA. A. niger and A. flavus instead of solubilizing adsorbed the metals in their biomass. Adsorption was mainly carried out by A. niger. (author)

Iron-chelating agents never suppress Fenton reaction but participate in quenching spin-trapped radicals

International Nuclear Information System (INIS)

Li Linxiang; Abe, Yoshihiro; Kanagawa, Kiyotada; Shoji, Tomoko; Mashino, Tadahiko; Mochizuki, Masataka; Tanaka, Miho; Miyata, Naoki

2007-01-01

Hydroxyl radical formation by Fenton reaction in the presence of an iron-chelating agent such as EDTA was traced by two different assay methods; an electron spin resonance (ESR) spin-trapping method with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and high Performance liquid chromatography (HPLC)-fluorescence detection with terephthalic acid (TPA), a fluorescent probe for hydroxyl radicals. From the ESR spin-trapping measurement, it was observed that EDTA seemed to suppress hydroxyl radical formation with the increase of its concentration. On the other hand, hydroxyl radical formation by Fenton reaction was not affected by EDTA monitored by HPLC assay. Similar inconsistent effects of other iron-chelating agents such as nitrylotriacetic acid (NTA), diethylenetriamine penta acetic acid (DTPA), oxalate and citrate were also observed. On the addition of EDTA solution to the reaction mixture 10 min after the Fenton reaction started, when hydroxyl radical formation should have almost ceased but the ESR signal of DMPO-OH radicals could be detected, it was observed that the DMPO-OH· signal disappeared rapidly. With the simultaneous addition of Fe(II) solution and EDTA after the Fenton reaction ceased, the DMPO-OH· signal disappeared more rapidly. The results indicated that these chelating agents should enhance the quenching of [DMPO-OH]· radicals by Fe(II), but they did not suppress Fenton reaction by forming chelates with iron ions

Chelation Therapy for Mercury Poisoning

OpenAIRE

Rong Guan; Han Dai

2009-01-01

Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role o...

f-Element Ion Chelation in Highly Basic Media

International Nuclear Information System (INIS)

Paine, R.T.

2000-01-01

A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelators for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

High-performance lithium-rich layered oxide materials: Effects of chelating agents on microstructure and electrochemical properties

International Nuclear Information System (INIS)

Li, Lingjun; Xu, Ming; Chen, Zhaoyong; Zhou, Xiang; Zhang, Qiaobao; Zhu, Huali; Wu, Chun; Zhang, Kaili

2015-01-01

The mechanisms and effects of three typical chelating agents, namely glucose, citric acid and sucrose on the sol-gel synthesis process, electrochemical degradation and structural evolution of 0.5Li 2 MnO 3 ·0.5LiNi 0.5 Co 0.2 Mn 0.3 O 2 (LLMO) materials are systematically compared for the first time. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis indicate that the sample synthesized from sucrose owns well structure, homogenous distribution, low Ni 3+ concentration and good surface structural stability during cycling, respectively. Electrochemical tests further prove that the LLMO material obtained from sucrose maintains 258.4 mAh g −1 with 94.8% capacity retention after 100 cycles at 0.2 C. The superior electrochemical performance can be ascribed to the exceptional complexing mechanism of sucrose, compared to those of the glucose and citric acid. Namely, one mole sucrose can be hydrolyzed into two different monosaccharides and further chelates three M (Li, Ni, Co and Mn) ions to form a more uniform ion-chelated matrix during sol-gel process. This discovery is an important step towards understanding the selection criterion of chelating agents for sol-gel method, that chelating agent with excellent complexing capability is beneficial to the distribution, structural stability and electrochemical properties of advanced lithium-rich layered materials

Effects of some chelating agents on the uptake and distribution of 54Mn(II) in the brown trout (Salmo trutta)

International Nuclear Information System (INIS)

Rouleau, C.; Tjaelve, H.; Pelletier, E.; Gottofrey, J.

1994-01-01

The effects of humic acids, which are natural metal-complexing compounds, and potassium ethylxanthate, sodium diethyldithiophosphate, sodium dimethyldithicarbamate, which are sulphur-containing man-made chelating agents, on the uptake and tissue distribution of 54 Mn(II) were studied in brown trout (Salmo trutta). Fish were exposed for 7 days to 0.1 μg Mn(II)x. -2 as NmCl 2 (l μCia 54 Mnxl -1 ) with or without chelat agents. Examination of the partition of Mn between octanol and a Tris-HCl buffer in the presence of these compounds was also performed. Humic acids had only small effects on Mn uptake and distribution in trout, probably because of the low stability of Mn-humate complexes. Partition of Mn in the presence of potassium ethylxanthate, sodium diethyldithiophosphate, sodium dimethyldithiocarbamate, and sodium diethyldithiocarbamate between octanol and Tris-HCl buffer showed formation of lipophilic complex with the latter two compounds, but not with the former. However, these four chelating agents all decreased Mn uptake in the trout by 40-45%. These substances also changed the distribution of Mn within the fish, with a higher proportion of the metal being present in some visceral organs and a smaller proportion being localized in some non-parenchymateous tissues, such as skin, fins and bones. The mechanisms underlying these effects are not known. however, the interaction of chelating agents with the Mn, although weak, may have partially withdrawn the metal from the uptake process inthe gills. The redistribution of Mn in the fish may be due to the binding of the metal to complexing compounds which have reached the intestinal lumen. Previous studies with other metals have shown increased or unchanged metal levels in tissues of fish at exposure together with potasium ethylxanthate, sodium diethyldithiophosphate, sodium dimethyldithiocarbamate, and sodium diethyldithiocarbamate, but decreased metal levels have not been observed before. (au) (37 refs.)

Chelation in Metal Intoxication

Directory of Open Access Journals (Sweden)

Swaran J.S. Flora

2010-06-01

Full Text Available Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications.

Article Commentary: Chelation Therapy for Mercury Poisoning

Directory of Open Access Journals (Sweden)

Rong Guan

2009-01-01

Full Text Available Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role of chelating agents against mercury poisoning, which provides a promising research direction for broader application of chelation therapy in prevention and treatment of mercury poisoning.

Synthesis and spectroscopic investigations of hydroxyapatite using a green chelating agent as template

Science.gov (United States)

Gopi, D.; Bhuvaneshwari, N.; Indira, J.; Kavitha, L.

2013-03-01

Hydroxyapatite [Ca10(PO4)6(OH)2, HAP] particles have been successfully synthesized by a cost-effective, eco-friendly green template method using natural and commercially available sucrose as a chelating agent. The sucrose used in this method has been extracted from various sources, three from natural and one from commercially available sources are exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology. Spectral characterizations involving Fourier transform infrared spectroscopy (FT-IR) for the functional group analysis of sucrose and HAP; carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) for the identification of the carbon atoms in sucrose and in HAP; liquid chromatography/mass spectrometry (LC-MS) for the determination of the hydrolyzed products of sucrose; and X-ray diffraction (XRD) techniques for the phase identification of the HAP particles were performed. The morphology of the HAP particles were assessed thoroughly using a scanning electron microscope (SEM) equipped with energy dispersive X-ray analysis (EDAX). The experimental results indicate that the obtained HAP using the natural sucrose as a chelating agent is of phase pure, with a well defined morphology having discrete particles without any agglomeration than the HAP from commercially available sucrose. Further, the reduced particle size can be achieved from the stem sugarcane extract as the source of the chelating agent.

Synthesis and spectroscopic investigations of hydroxyapatite using a green chelating agent as template.

Science.gov (United States)

Gopi, D; Bhuvaneshwari, N; Indira, J; Kavitha, L

2013-03-01

Hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2), HAP] particles have been successfully synthesized by a cost-effective, eco-friendly green template method using natural and commercially available sucrose as a chelating agent. The sucrose used in this method has been extracted from various sources, three from natural and one from commercially available sources are exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology. Spectral characterizations involving Fourier transform infrared spectroscopy (FT-IR) for the functional group analysis of sucrose and HAP; carbon-13 nuclear magnetic resonance spectroscopy ((13)C NMR) for the identification of the carbon atoms in sucrose and in HAP; liquid chromatography/mass spectrometry (LC-MS) for the determination of the hydrolyzed products of sucrose; and X-ray diffraction (XRD) techniques for the phase identification of the HAP particles were performed. The morphology of the HAP particles were assessed thoroughly using a scanning electron microscope (SEM) equipped with energy dispersive X-ray analysis (EDAX). The experimental results indicate that the obtained HAP using the natural sucrose as a chelating agent is of phase pure, with a well defined morphology having discrete particles without any agglomeration than the HAP from commercially available sucrose. Further, the reduced particle size can be achieved from the stem sugarcane extract as the source of the chelating agent. Copyright © 2012 Elsevier B.V. All rights reserved.

Sulfur equilibrium desulfurization of sulfur containing products of combustion

International Nuclear Information System (INIS)

Woodroffe, J.A.; Abichandani, J.S.

1990-01-01

This patent describes the method for the combustion of a carbon- and sulfur-containing fuel for substantially reducing emission of gaseous sulfur compounds formed during combustion of the fuel in a combustion zone. The zone having one or more fuel inlets and one or more oxidizer inlets, and having a combustion products outlet spaced therefrom, and having one or more inorganic sorbent inlets downstream of the fuel inlet(s) and oxidizer inlet(s) and upstream of the combustion products outlet

Results of Study of Sulfur Oxide Reduction During Combustion of Coal-Water Slurry Fuel Through use of Sulfur Capturing Agents

Directory of Open Access Journals (Sweden)

Murko Vasiliy I.

2016-01-01

Full Text Available It is shown that an effective way of burning high sulfur coal is to burn coal-water slurry fuel (CWF prepared on its basis containing a sulfur capture agent (SCA entered in the slurry at the stage of preparation. The technique of thermodynamic analysis of chemical reactions during CWF burning has been developed including burning in the presence of SCA. Using the developed calculation program, the optimal temperature conditions have been determined as required for the effective reduction of sulfur oxides in flue gases when using different types of SCA. According to the results of calculating the composition of CWF combustion products when entering various substances in the burner space as SCA it has been determined that magnesite, calcite, and dolomite are the most effective natural minerals. The analysis of calculated and experimental data proves the efficiency of SCA addition as well as validity of the obtained results.

Method of removing and recovering elemental sulfur from highly reducing gas streams containing sulfur gases

Science.gov (United States)

Gangwal, Santosh K.; Nikolopoulos, Apostolos A.; Dorchak, Thomas P.; Dorchak, Mary Anne

2005-11-08

A method is provided for removal of sulfur gases and recovery of elemental sulfur from sulfur gas containing supply streams, such as syngas or coal gas, by contacting the supply stream with a catalyst, that is either an activated carbon or an oxide based catalyst, and an oxidant, such as sulfur dioxide, in a reaction medium such as molten sulfur, to convert the sulfur gases in the supply stream to elemental sulfur, and recovering the elemental sulfur by separation from the reaction medium.

Enhanced in vitro activity of tigecycline in the presence of chelating agents.

Science.gov (United States)

Deitchman, Amelia N; Singh, Ravi Shankar Prasad; Rand, Kenneth H; Derendorf, Hartmut

2018-05-01

The lack of availability of novel antibiotic agents and the rise of resistance to existing therapies has led clinicians to utilise combination therapy to adequately treat bacterial infections. Here we examined how chelators may impact the in vitro activity of tigecycline (TIG) against Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae. Minimum inhibitory concentrations (MICs) were determined by broth dilution with and without various combinations of chelators (EDTA and other tetracyclines) and metal ions (i.e. calcium, magnesium). Trimethoprim (TMP) was used as a non-chelating control. Addition of metal ions led to increases in MICs, whilst addition of EDTA led to decreases in MICs. The chelating effects of EDTA were reversed by addition of magnesium and most profoundly calcium. Similar effects of EDTA and calcium were observed for tetracycline (TET) and TMP. When other tetracyclines (TET, oxytetracycline (OXY) and chlortetracycline (CHL)) were used as chelators at concentrations below their MICs, TIG MICs decreased for P. aeruginosa but not for E. coli. Some decreases in TIG MICs were observed for K. pneumoniae when TET and CHL were added. A dose-dependent decrease in TIG MIC was observed for TET and was reversed by the addition of calcium. The presence of effects of EDTA and calcium on TMP MICs indicates that mechanisms outside of TIG chelation likely play a role in enhanced activity. Full characterisation of an unexpected interaction such as TIG-TET with different microorganisms could provide valuable insights into the underlying mechanisms and design of physiologically viable chelators as candidates for future combinations regimens. Copyright © 2018 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

[Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

International Nuclear Information System (INIS)

1991-01-01

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III)

[Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

Energy Technology Data Exchange (ETDEWEB)

1991-12-31

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

(Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents)

Energy Technology Data Exchange (ETDEWEB)

1991-01-01

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

f-Element Ion Chelation in Highly Basic Media - Final Report

International Nuclear Information System (INIS)

Paine, R.T.

2000-01-01

A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelator s for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

XAS studies of the effectiveness of iron chelating treatments of Mary Rose timbers

International Nuclear Information System (INIS)

Berko, A; Schofield, E J; Chadwick, A V; Smith, A D; Jones, A M; Mosselmans, J F W

2009-01-01

The oxidation of sulfur in marine archaeological timbers under museum storage conditions is a recently identified problem, particularly for major artefacts such as historic ships excavated from the seabed. Recent work on the Vasa has stressed the role of iron in catalysing the oxidative degradation of the wood cellulose and the polyethylene glycols used to restore mechanical integrity to the timbers. In developing new treatment protocols for the long term preservation of Henry VIII of England's flagship, the Mary Rose, we are investigating the potential of chelating agents to neutralise and remove the iron products from the ships timbers. We have explored the use of aqueous solutions of chelating agents of calcium phytate, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) and ammonium citrate to extract the iron compounds. All of these solutions exhibit some level of iron removal; however the key is to find the most effective concentration at pH of around 7 of the reagent solution, to minimise the treatment time and find the most cost-effective treatment for the whole of the Mary Rose hull. Fe K-edge XAFS data from samples of Mary Rose timbers, before and after treatment by the chelating agents mentioned has been collected. The data collected provide valuable insights into the effectiveness of the treatment solutions.

[Enhanced phytoextraction of heavy metal contaminated soil by chelating agents and auxin indole-3-acetic acid].

Science.gov (United States)

Zhou, Jian-min; Dang, Zhi; Chen, Neng-chang; Xu, Sheng-guang; Xie, Zhi-yi

2007-09-01

The environmental risk of chelating agents such as EDTA application to the heavy metals polluted soils and the stress on plant roots due to the abrupt increase metals concentration limit the wide commercial use of chelate-induced phytoextraction. Chelating agent ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) and auxin indole-3-acetic acid (IAA) were used for enhancing heavy metals uptake from soils by Zea mays L. (corn) in pot experiments. The metals content in plant tissues was quantified using an inductively coupled plasma mass spectrometer (ICP-MS). The results showed that the combination of IAA and EDTA increased the biomass by about 40.0% and the contents of Cu, Zn, Cd and Pb in corn shoots by 27.0%, 26.8%, 27.5% and 32.8% respectively, as compared to those in EDTA treatment. While NTA&IAA treatment increased the biomass by about 29.9% and the contents of Cu, Zn, Cd and Pb in corn shoots by 31.8%, 27.6%, 17.0% and 26.9% respectively, as compared to those in NTA treatment. These results indicated that corn growth was promoted, and the biomass and the accumulation of heavy metals in plant shoots were increased significantly with the addition of IAA, which probably helps to change the cell membrane properties and the biomass distribution, resulting in the alleviation of the phytotoxicity of metals and the chelating agents.

Leach studies of chelating agents and influence on radionuclide leaching from simulated LLW/ILW cement waste forms

International Nuclear Information System (INIS)

Vejmelka, P.; Koester, R.; Ferrara, D.; Wacks, M.E.

1990-01-01

Leach studies were performed on cemented waste forms containing sodium nitrate, trace amounts of cesium-137, and cobalt-60, and a chelating agent (ethylene diamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), or citric acid). Leaching of the chelates was measured in water and the effect of the chelates on the release of the Cs-137 and Co-60 was studied. The time dependence of the release rate of the chelates is comparable but the chelate concentration in solution and the released fractions are different. EDTA shows the highest release rate followed by NTA and citrate. The release of the non complex forming cesium is not affected by the presence of the chelates. Independent from the strong complex formation of cobalt with EDTA, NTA, and citrate in the alkaline region the cobalt release is also not affected by the presence of the chelates. The high calcium content of the system decreases the stability of the Co complexes in the high pH region (12-13). Experiments were performed to determine the equilibrium concentration of the chelates between liquid and solid phases. The liquid phases were deionized water, saturated sodium chloride, 24 percent magnesium chloride and Q-brine. The equilibrium studies are based on the assumption that in time a stable final condition is to be established in the near field of the waste form in which each compound is at chemical equilibrium between the dissolved and the various solid phases. The total release may be assessed from the concentration in solution and flow rate out of the near field. The fraction of EDTA released from the cement ranged from 0.2 in the Q-brine to 0.5 in the saturated sodium chloride. The concentration of EDSA in solution was dependent on the original amount in the cement sample, but the released fraction was independent of the initial loading. Indicating, EDTA concentration is not affected by solubility limits. 11 refs., 3 figs., 2 tabs

Self-diffusion coefficient of iron as affected by chelating agents using tracer technique

International Nuclear Information System (INIS)

Massoud, M.A.; Abd-El-Sabour, M.F.; Omar, M.A.

1983-01-01

The effect of Fe 2 (So 4 ) 3 , Fe-DTPA, and Fe-EDDHA on the self-diffusion coefficient of Fe in some soils of Egypt was studied. The effect of chelating compounds on the ratio between solid phase fraction of the labile Fe and its concentration in the soil solution (capacity factor) was also studied. The data reveals the following items of more interesting: 1) The use of chelating agents, i.e., DTPA and EDDHA increased the amount of Fe in soil solution, hence the capacity factor was decreased using these compounds. It seems that as the addition of Fe was in the chelated form in soil solution, the slight loss of 59Fe from solution when 59Fe - chelate was used could be attributed to the isotopic exchange with soil Fe. 2) It was found that the addition of either Fe-DTPA or Fe-EDDHA significantly increased the self-diffusion of Fe in soil as compared with Fe 2 (So 4 ) 3 . It was also noticed that the self-diffusion for Fe in the alluvial soil was greater than in the calcareous one due to the instance competition between Ca and Fe for the chelating ligands in the calcareous soil. It was also seen that soil texture affects Fe self-diffusion

Cell-permeable Ln(III) chelate-functionalized InP quantum dots as multimodal imaging agents.

Science.gov (United States)

Stasiuk, Graeme J; Tamang, Sudarsan; Imbert, Daniel; Poillot, Cathy; Giardiello, Marco; Tisseyre, Céline; Barbier, Emmanuel L; Fries, Pascal Henry; de Waard, Michel; Reiss, Peter; Mazzanti, Marinella

2011-10-25

Quantum dots (QDs) are ideal scaffolds for the development of multimodal imaging agents, but their application in clinical diagnostics is limited by the toxicity of classical CdSe QDs. A new bimodal MRI/optical nanosized contrast agent with high gadolinium payload has been prepared through direct covalent attachment of up to 80 Gd(III) chelates on fluorescent nontoxic InP/ZnS QDs. It shows a high relaxivity of 900 mM(-1) s(-1) (13 mM(-1 )s(-1) per Gd ion) at 35 MHz (0.81 T) and 298 K, while the bright luminescence of the QDs is preserved. Eu(III) and Tb(III) chelates were also successfully grafted to the InP/ZnS QDs. The absence of energy transfer between the QD and lanthanide emitting centers results in a multicolor system. Using this convenient direct grafting strategy additional targeting ligands can be included on the QD. Here a cell-penetrating peptide has been co-grafted in a one-pot reaction to afford a cell-permeable multimodal multimeric MRI contrast agent that reports cellular localization by fluorescence and provides high relaxivity and increased tissue retention with respect to commercial contrast agents.

Sulfur polymer cement, a solidification and stabilization agent for hazardous and radioactive wastes

International Nuclear Information System (INIS)

Darnell, G.R.

1992-01-01

Hydraulic cements have been the primary radioactive waste stabilization agents in the United States for 50 years. Twelve years ago, Brookhaven National Laboratory was funded by the Department of Energy's Defense Low-Level Waste Management Program to test and develop sulfur polymer cement (SPC). It has stabilized routine wastes as well as some troublesome wastes with high waste-to-agent ratios. The Department of Energy's Hazardous Waste Remedial Action Program joined the effort by providing funding for testing and developing sulfur polymer cement as a hazardous-waste stabilization agent. Sulfur polymer cement has passed all the laboratory scale tests required by the US Environmental Protection Agency and US Nuclear Regulatory Commission. Two decades of tests by the US Bureau of Mines and private concrete contractors indicate this agent is likely to exceed other agents in longevity. This bulletin provides technical data from pertinent tests conducted by these various entities

Self-diffusion coefficient of iron as affected by chelating agents using tracer technique

Energy Technology Data Exchange (ETDEWEB)

Massoud, M.A.; Abd-El-Sabour, M.F. (Agriculture Dept. for Soil and Water Research, Nuclear Research Centre, A.E.A., Cairo (Egypt)); Omar, M.A. (Ain Shams Univ., Cairo (Egypt). Faculty of Agriculture)

1983-01-01

The effect of Fe/sub 2/(So/sub 4/)/sub 3/, Fe-DTPA, and Fe-EDDHA on the self-diffusion coefficient of Fe in some soils of Egypt was studied. The effect of chelating compounds on the ratio between solid phase fraction of the labile Fe and its concentration in the soil solution (capacity factor) was also studied. The data reveals the following items of more interesting: 1) The use of chelating agents, i.e., DTPA and EDDHA increased the amount of Fe in soil solution, hence the capacity factor was decreased using these compounds. It seems that as the addition of Fe was in the chelated form in soil solution, the slight loss of 59Fe from solution when 59Fe - chelate was used could be attributed to the isotopic exchange with soil Fe. 2) It was found that the addition of either Fe-DTPA or Fe-EDDHA significantly increased the self-diffusion of Fe in soil as compared with Fe/sub 2/(So/sub 4/)/sub 3/. It was also noticed that the self-diffusion for Fe in the alluvial soil was greater than in the calcareous one due to the instance competition between Ca and Fe for the chelating ligands in the calcareous soil. It was also seen that soil texture affects Fe self-diffusion.

Transnitrosation of alicyclic N-nitrosamines containing a sulfur atom.

Science.gov (United States)

Inami, Keiko; Kondo, Sonoe; Ono, Yuta; Saso, Chiharu; Mochizuki, Masataka

2013-12-15

Aromatic and aliphatic nitrosamines are known to transfer a nitrosonium ion to another amine. The transnitrosation of alicyclic N-nitroso compounds generates S-nitrosothiols, which are potential nitric oxide donors in vivo. In this study, certain alicyclic N-nitroso compounds based on non-mutagenic N-nitrosoproline or N-nitrosothioproline were synthesised, and the formation of S-nitrosoglutathione (GSNO) was quantified under acidic conditions. We then investigated the effect of a sulfur atom as the substituent and as a ring component on the GSNO formation. In the presence of thiourea under acidic conditions, GSNO was formed from N-nitrosoproline and glutathione, and an N-nitroso compound containing a sulfur atom and glutathione produced GSNO without thiourea. The quantity of GSNO derived from the reaction of the N-nitrosamines containing a sulfur atom and glutathione was higher than that from the N-nitrosoproline and glutathione plus thiourea. Among the analogues that contained a sulfur atom either in the ring or as a substituent, the thiazolidines produced a slightly higher quantity of GSNO than the analogue with a thioamide group. A compound containing sulfur atoms both in the ring and as a substituent exhibited the highest activity for GSNO formation among the alicyclic N-nitrosamines tested. The results indicate that the intramolecular sulfur atom plays an important role in the transnitrosation via alicyclic N-nitroso compounds to form GSNO. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Intrinsic dependence of the magnetic properties of CoFe{sub 2}O{sub 4} nanoparticles prepared via chemical methods with addition of chelating agents

Energy Technology Data Exchange (ETDEWEB)

Mendonça, E.C. [Núcleo de Pós-Graduação em Física, Campus Prof. José Aluísio de Campos, UFS, 49100-000 São Cristóvão, SE (Brazil); Tenório, Mayara A. [Departamento de Física, Campus Prof. Alberto Carvalho, UFS, 49500-000 Itabaiana, SE (Brazil); Mecena, S.G.; Zucolotto, B.; Silva, L.S. [Núcleo de Pós-Graduação em Física, Campus Prof. José Aluísio de Campos, UFS, 49100-000 São Cristóvão, SE (Brazil); Jesus, C.B.R. [Instituto de Física Gleb Wataghin, UNICAMP, C. P. 6165, 13083-970 Campinas, SP (Brazil); Meneses, C.T. [Núcleo de Pós-Graduação em Física, Campus Prof. José Aluísio de Campos, UFS, 49100-000 São Cristóvão, SE (Brazil); and others

2015-12-01

In this work, the effect of addition of different chelating agents on the magnetic properties of cobalt ferrite nanoparticles produced by the combining of both co-precipitation and hydrothermal methods is reported. The Rietveld analyses of X-ray diffraction patterns reveal that our samples are single phase (space group: Fd-3m) with small average sizes. The weight losses observed in the thermogravimetric measurements together with the M×H curves show that the organic contamination coming from chelating agent decomposition can give rise to misinterpretation of the magnetization measurements. Besides, analyses of the zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurements and the M×H curves measured at room temperature allows us to state that both the average blocking temperature and particles size distribution are sensitive to the kind of chelating agent. - Highlights: Superparamagnetism. Chelating agents. Organic contamination.

Process for removing sulfur from sulfur-containing gases: high calcium fly-ash

Science.gov (United States)

Rochelle, Gary T.; Chang, John C. S.

1991-01-01

The present disclosure relates to improved processes for treating hot sulfur-containing flue gas to remove sulfur therefrom. Processes in accordance with the present invention include preparing an aqueous slurry composed of a calcium alkali source and a source of reactive silica and/or alumina, heating the slurry to above-ambient temperatures for a period of time in order to facilitate the formation of sulfur-absorbing calcium silicates or aluminates, and treating the gas with the heat-treated slurry components. Examples disclosed herein demonstrate the utility of these processes in achieving improved sulfur-absorbing capabilities. Additionally, disclosure is provided which illustrates preferred configurations for employing the present processes both as a dry sorbent injection and for use in conjunction with a spray dryer and/or bagfilter. Retrofit application to existing systems is also addressed.

A neutral polydisulfide containing Gd(III) DOTA monoamide as a redox-sensitive biodegradable macromolecular MRI contrast agent.

Science.gov (United States)

Ye, Zhen; Zhou, Zhuxian; Ayat, Nadia; Wu, Xueming; Jin, Erlei; Shi, Xiaoyue; Lu, Zheng-Rong

2016-01-01

This work aims to develop safe and effective gadolinium (III)-based biodegradable macromolecular MRI contrast agents for blood pool and cancer imaging. A neutral polydisulfide containing macrocyclic Gd-DOTA monoamide (GOLS) was synthesized and characterized. In addition to studying the in vitro degradation of GOLS, its kinetic stability was also investigated in an in vivo model. The efficacy of GOLS for contrast-enhanced MRI was examined with female BALB/c mice bearing 4T1 breast cancer xenografts. The pharmacokinetics, biodistribution, and metabolism of GOLS were also determined in mice. GOLS has an apparent molecular weight of 23.0 kDa with T1 relaxivities of 7.20 mM(-1) s(-1) per Gd at 1.5 T, and 6.62 mM(-1) s(-1) at 7.0 T. GOLS had high kinetic inertness against transmetallation with Zn(2+) ions, and its polymer backbone was readily cleaved by L-cysteine. The agent showed improved efficacy for blood pool and tumor MR imaging. The structural effect on biodistribution and in vivo chelation stability was assessed by comparing GOLS with Gd(HP-DO3A), a negatively charged polydisulfide containing Gd-DOTA monoamide GODC, and a polydisulfide containing Gd-DTPA-bisamide (GDCC). GOLS showed high in vivo chelation stability and minimal tissue deposition of gadolinium. The biodegradable macromolecular contrast agent GOLS is a promising polymeric contrast agent for clinical MR cardiovascular imaging and cancer imaging. Copyright © 2015 John Wiley & Sons, Ltd.

Nature of the bifunctional chelating agent used for radioimmunotherapy with yttrium-88 monoclonal antibodies: critical factors in determining in vivo survival and organ toxicity

Energy Technology Data Exchange (ETDEWEB)

Kozak, R.W.; Raubitschek, A.; Mirzadeh, S.; Brechbiel, M.W.; Junghaus, R.; Gansow, O.A.; Waldmann, T.A. (Center for Biologics Evaluation and Research, FDA, Bethesda, MD (USA))

1989-05-15

One factor that is critical to the potential effectiveness of radioimmunotherapy is the design of radiometal-chelated antibodies that will be stable in vivo. Stability in vivo depends on the condition that both the chelate linkage and radiolabeling procedures not alter antibody specificity and biodistribution. In addition, synthesis and selection of the chelating agent is critical for each radiometal in order to prevent inappropriate release of the radiometal in vivo. In the present study, we compare the in vivo stability of seven radioimmunoconjugates that use different polyaminocarboxylate chelating agents to complex yttrium-88 to the mouse anti-human interleukin-2 receptor monoclonal antibody, anti-Tac. Chelate linkage and radiolabeling procedures did not alter the immunospecificity of anti-Tac. In order to assess whether yttrium was inappropriately released from the chelate-coupled antibody in vivo, iodine-131-labeled and yttrium-88 chelate-coupled antibodies were simultaneously administered to the same animals to correlate the decline in yttrium and radioiodinated antibody activity. The four stable yttrium-88 chelate-coupled antibodies studied displayed similar iodine-131 and yttrium-88 activity, indicating minimal elution of yttrium-88 from the complex. In contrast, the unstable yttrium-88 chelate-coupled antibodies had serum yttrium-88 activities that declined much more rapidly than their iodine-131 activities, suggesting loss of the radiolabel yttrium-88 from the chelate. Furthermore, high rates of yttrium-88 elution correlated with deposition in bone. Four chelating agents emerged as promising immunotherapeutic reagents: isothiocyanate benzyl DTPA and its derivatives 1B3M, MX, and 1M3B.

Chelation studies involving decontamination of light lanthanides by polyaminopolycarboxylic

International Nuclear Information System (INIS)

Hassan, N.E.H.

1985-01-01

The present thesis constitutes chelation studies involving decontamination of light lanthanides, cobalt , and uranium with 2,2-bis-acryloyliminomethylene- acid (BAETA) using the spectrophotometric method. the work carried out aimed to clear up the effectiveness of BAETA as a decontaminating agent for radioactive nuclides from human body . the thesis includes a general introduction , outlines the aim of work and contains three main chapters . the results of the work are discussed at the end of the thesis. the first chapter deals with a comprehensive survey of the relevant literature. this includes the metabolism and toxicity of cerium, uranium, cobalt and Ln +3 elements, general methodologies of internal decontamination, choice and effectiveness of chelating agents

Effect of pH on the release of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resins collected from operating nuclear power stations

International Nuclear Information System (INIS)

McIsaac, C.V.; Akers, D.W.; McConnell, J.W.

1991-06-01

Data are presented on the physical stability and leachability of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small-scale waste--form specimens collected during solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station were leach-tested and subjected to compressive strength testing in accordance with the Nuclear Regulatory Commission's ''Technical Position on Waste Form'' (Revision 1). Samples of untreated resin waste collected from each solidification vessel before the solidification process were analyzed for concentrations of radionuclides, selected transition metals, and chelating agents to determine the quantities of these chemicals in the waste-form specimens. The chelating agents included oxalic, citric, and picolinic acids. In order to determine the effect of leachant chemical composition and pH on the stability and leachability of the waste forms, waste-form specimens were leached in various leachants. Results of this study indicate that differences in pH do not affect releases from cement-solidified decontamination ion-exchange resin waste forms, but that differences in leachant chemistry and the presence of chelating agents may affect the releases of radionuclides and chelating agents. Also, this study indicates that the cumulative releases of radionuclides and chelating agents are similar for waste- form specimens that decomposed and those that retained their general physical form. 36 refs., 60 figs., 28 tabs

Chelating agents improve enzymatic solubilization of pectinaceous co-processing streams

DEFF Research Database (Denmark)

Ravn, Helle Christine; Meyer, Anne S.

2014-01-01

of different levels of ethylene-diaminetetraacetic acid (EDTA), citric acid, oxalic acid, and phosphate was assessed in relation to enzymatic solubilization of isopropanol precipitatable oligo- and polysaccharides from sugar beet pulp, citrus peel, and two types of potato pulp. The two types of potato pulp...... solubilization yields. The effect of the chelating agents correlated to their dissociation constants (pKa values) and calcium binding constants and citric acid and EDTA exerted highest effects. Maximum polysaccharide yield was obtained for FiberBind 400 where the enzymatic treatment in presence of citric acid...

Method of burning sulfur-containing fuels in a fluidized bed boiler

Science.gov (United States)

Jones, Brian C.

1982-01-01

A method of burning a sulfur-containing fuel in a fluidized bed of sulfur oxide sorbent wherein the overall utilization of sulfur oxide sorbent is increased by comminuting the bed drain solids to a smaller average particle size, preferably on the order of 50 microns, and reinjecting the comminuted bed drain solids into the bed. In comminuting the bed drain solids, particles of spent sulfur sorbent contained therein are fractured thereby exposing unreacted sorbent surface. Upon reinjecting the comminuted bed drain solids into the bed, the newly-exposed unreacted sorbent surface is available for sulfur oxide sorption, thereby increasing overall sorbent utilization.

Improving the efficiency of phytoremediation using electrically charged plant and chelating agents.

Science.gov (United States)

Tahmasbian, Iman; Safari Sinegani, Ali Akbar

2016-02-01

The low efficiency of phytoremediation is a considerable problem that limits the application of this environmentally friendly method on heavy metal-polluted soils. The combination of chelate-assisted phytoextraction and electrokinetic remediation could offer new opportunities to improve the effectiveness of phytoextraction. The current experiment aims to investigate the effects of electrical fields and chelating agents on phytoremediation efficiency. In a pot experiment using mine soil, poultry manure extract (PME), cow manure extract (CME), and ethylenediaminetetraacetic acid (EDTA) were applied to soil as chelating agents (2 g kg(-1)) at the beginning of the flowering stage. A week later, Helianthus annuus (sunflower) was negatively charged by inserting a stainless steel needle with 10 and 30 V DC electricity in the lowest part of the stems for 1 h each day for a 14-day period. At the end of the experiment, the shoot and root dry weight, lead (Pb) concentration in plant organs, translocation factor (TF), metal uptake index (UI), and soil available Pb (diethylene triamine pentaacetic acid (DTPA) extractable) were detected. Results indicated that the application of electrical fields had no significant impact on the shoot and root dry weights, while Pb concentration and UI increased in the 10-V EDTA treatment by 500 % compared to control. There was no significant difference between UI in 30- and 10-V EDTA treatments. Soil available Pb significantly increased in the 30-V treated soil. A positive correlation was observed between the available Pb in soil near the root and Pb concentration in shoot, its TF, and UI. In conclusion, a negatively charged plant along with the application of EDTA significantly increased the phytoremediation efficiency.

Chelation in metal intoxication

DEFF Research Database (Denmark)

Aaseth, Jan; Skaug, Marit Aralt; Cao, yang

2015-01-01

The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the incon......The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due...... to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment...... of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new...

Role of different chelating agent in synthesis of copper doped tin oxide (Cu-SnO2) nanoparticles

Science.gov (United States)

Saravanakumar, B.; Anusiya, A.; Rani, B. Jansi; Ravi, G.; Yuvakkumar, R.

2018-05-01

An attempt was made to synthesis the copper doped tin oxide (Cu-SnO2) nanoparticles by adopting different chelating agents (NaOH, KOH and C2H2O4) by Sol-gel process. The synthesized products were characterized by XRD, Photoluminescence (PL), Infra- Red (FTIR) and SEM analysis. The XRD confirms the formation of Cu-SnO2 shows the maximum peak at 33.8° with lattice plane (101). The PL peak at 361 and 382 nm due to the recombination of electron in conduction band to valence band infers the optical properties. The IR spectra correspond to the peak at 551 and 620 cm-1 attributed to the characteristics peak for Cu-SnO2 nanoparticles. The SEM images for all three Cu-SnO2 nanoparticles formed by three chelating agent (NaOH, KOH and C2H2O4) facilitates the formation mechanism and the chelating agent Oxalic acid results in formation of nano flowers with diverse layers orientated in random direction. Further SEM studies reveal that, the Cu-SnO2 nanoparticles formed by oxalic acid could posses high surface area with large number layered structured enables the better electrochemical properties and its applications.

Comparative studies of 111In-labeled monoclonal antibody using spacer-containing and non-spacer bifunctional chelates. 2

International Nuclear Information System (INIS)

Sun, Baofu

1994-01-01

Indium-111-labeled A7 monoclonal antibodies using two spacer-containing chelates, succinimido-EGS-DTPA (EGS-DTPA: diester spacer) and maleimido-C10-Bz-EDTA (C10-Bz-EDTA: hydrocarbon spacer) were investigated in human LS180 colon tumor bearing nude mice and were compared with two non-spacer chelates, cyclic DTPA dianhydride (cDTPAA) and isothiocyanatobenzyl-EDTA (SCN-Bz-EDTA). Compared with immunoconjugates using non-spacer chelates, immunoconjugates using spacer-containing chelates, especially C10-Bz-EDTA-A7 showed lower 111 In activity in normal organs. The radioactivity in the liver for C10-Bz-EDTA-A7 decreased continuously till 96 hrs postinjection, however, this liver radioactivity for EGS-DTPA-A7 showed little change after 24 hrs. Moreover, in liver subcellular distribution study, EGS-DTPA-A7 showed a higher activity retention in mitochondrial fraction which contained lysosome, a place for metabolizing and storing of 111 In labeled antibody, than that of C10-Bz-EDTA-A7. The C10-Bz-EDTA-A7 conjugate demonstrated more preferable tumor-to-non tumor contrast on the scintigrams than that found with other three immunoconjugates. Up to 96 hrs postinjection, tumor bearing nude mice injecting with immunoconjugates using spacer-containing chelates exreted twice radioactivity from whole body than that excreted by using non-spacer chelates. Interestingly, different from other three chelates, C10-Bz-EDTA-A7 were mainly excreted via feces. We conclude that the decrease of radioactivity in normal tissues in the case of EGS-DTPA-A7 was due to the rapid decrease of activity in the blood, while in the case of C10-Bz-EDTA-A7 it was due to the quickly excreted small metabolite through faces. 111 In labeled C10-Bz-EDTA conjugate is superior, at least when conjugated with A7, to other three chelate conjugates used in this study. (author)

Organically complexed copper, zinc, and chelating agents in the rivers of Western Puerto Rico

International Nuclear Information System (INIS)

Montgomery, J.R.; Echevarria, J.E.

1975-01-01

The method for determining soluble chelators gives their concentration in copper-equivalent chelating capacity units in fresh or slightly brackish (less than 3 percent salinity) water. The mean concentration of chelators in the Rio Guanajibo for December 1973 and January 1974 was 0.4 mg of copper per liter of water (N = 21, SD = 0.2) and for February 1974, 0.9 mg/liter (N = 8, SD = 0.4). The combined mean for the Rio Anasco and Culebrinas was 0.5 mg/liter (N = 7, SD = 0.4) in January and February 1974. The mean concentration of ionic copper was 0.5 μg/liter (N = 7, SD = 0.6) and of ionic zinc, 0.2 μg/liter (N = 8, SD = 0.1) in the Rio Guanajibo from November 1972 to February 1973. The concentration of organically bound copper was 0.3 μ/liter (N = 7, SD = 0.2) and that of organically bound zinc was 0.6 μg/liter (N = 8, SD = 0.6); this indicates that there was more than a sufficient quantity of chelator available in the river to complex all the soluble copper. The presence of a high ratio of Ca 2+ to Cu 2+ probably prevents the formation of larger concentrations of organically complexed copper. The mean concentration of chelating agents in the Guanajibo River seems to be directly related to the increased organic input from municipalities and a sugar mill. The concentration of chelators in tropical rivers appears to be higher than that found in Canadian lakes. The mean concentration for particulate organic carbon (POC) was 3653 μg atoms/liter (SD = 3653, N = 29). The dissolved reactive phosphate (DRP) ranged from a mean of 1.1 μg atom/liter. No significant correlation could be found between POC, DRP, and the concentration of chelators

N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases

Directory of Open Access Journals (Sweden)

Andrea Giampreti

2016-01-01

Full Text Available Systemic toxicity associated with cobalt (Co and chromium (Cr containing metal hip alloy may result in neuropathy, cardiomyopathy, and hypothyroidism. However clinical management concerning chelating therapy is still debated in literature. Here are described two metal-on-metal hip-implanted patients in which N-acetyl-cysteine decreased elevated blood metal levels. A 67-year-old male who underwent Co/Cr hip implant in September 2009 referred to our Poison Control Centre for persisting elevated Co/Cr blood levels (from March 2012 to November 2014. After receiving oral high-dose N-acetyl-cysteine, Co/Cr blood concentrations dropped by 86% and 87% of the prechelation levels, respectively, and persisted at these latter concentrations during the following 6 months of follow-up. An 81-year-old female who underwent Co/Cr hip implant in January 2007 referred to our Centre for detection of high Co and Cr blood levels in June 2012. No hip revision was indicated. After a therapy with oral high-dose N-acetyl-cysteine Co/Cr blood concentrations decreased of 45% and 24% of the prechelation levels. Chelating agents reported in hip-implanted patients (EDTA, DMPS, and BAL are described in few cases. N-acetyl-cysteine may provide chelating sites for metals and in our cases reduced Co and Cr blood levels and resulted well tolerable.

Monitoring the effects of chelating agents and electrical fields on active forms of Pb and Zn in contaminated soil.

Science.gov (United States)

Tahmasbian, Iman; Safari Sinegani, Ali Akbar

2013-11-01

The application of electrical fields and chelating agents is an innovative hybrid technology used for the decontamination of soil polluted by heavy metals. The effects of four center-oriented electrical fields and chelating agents on active fractions of lead and zinc were investigated in this pot experiment. Ethylenediaminetetraacetic acid (EDTA) as a synthetic chelator and cow manure extract (CME) and poultry manure extract (PME) as natural chelators were applied to the pots (2 g kg(-1)) 30 days after the first irrigation. Two weeks later, four center-oriented electrical fields were applied in each pot (in three levels of 0, 10, and 30 V) for 1 h each day for 14 days. The soil near the cathode and anodes was collected and analyzed as cathodic and anodic soil, respectively. Results indicated that the soluble-exchangeable fraction of lead and zinc were decreased in the cathodic soil, while the carbonate-bound fractions were increased. In the anodic soil, however, the opposite result was observed. EDTA enhanced the soluble-exchangeable form of the metals in both anodic and cathodic soils. Furthermore, the amounts of carbonate-bound heavy metals were increased by the application of CME in both soils. The organic-bound fraction of the metals was increased by the application of natural chelators, while electrical fields had no significant impacts on this fraction.

Sulfur Fixation by Chemically Modified Red Mud Samples Containing Inorganic Additives: A Parametric Study

Directory of Open Access Journals (Sweden)

Yang Liu

2016-01-01

Full Text Available Sulfur retention ability of Bayer red mud from alumina plant was investigated. Bayer red mud modified by fusel salt and waste mother liquor of sodium ferrocyanide as the main sulfur fixation agent and the calcium based natural mineral materials as servicing additives; the experimental results showed the following: (1 Through 10 wt% waste mother liquor of sodium ferrocyanide modifying Bayer red mud, sulfur fixation rate can increase by 13 wt%. (2 Magnesium oxide can obviously improve the sulfur fixation performance of Bayer red mud and up to a maximum sulfur fixation rate of 47 wt% at adding 1 wt% magnesium oxide. (3 Dolomite enhanced the sulfur fixation performances with the sulfur fixation rate of 68 wt% in optimized condition. (4 Vermiculite dust reduced sulfur dioxide during the fixed-sulfur process of modified Bayer red mud, and the desulphurization ration could reach up to a maximum 76 wt% at 950°C. (5 An advanced three-component sulfur fixation agent was investigated, in which the optimized mass ratio of modified Bayer red mud, dolomite, and vermiculite dust was 70 : 28 : 2 in order, and its sulfur fixation efficiency has reached to a maximum 87 wt% under its 20 wt% dosage in the coal.

Electrical properties of a new sulfur-containing polymer for optoelectronic application

Science.gov (United States)

ElAkemi, ElMehdi; Jaballah, Nejmeddine; Ouada, Hafedh Ben; Majdoub, Mustapha

2015-06-01

An original polythiophene derivative was characterized to develop the optoelectronic properties of sulfur-containing π-conjugated polymer. The optical properties of the polymer were investigated by UV-visible absorption spectroscopy and atomic force microscopy. Investigations of the electrical characteristics of polymer diodes are reported. We present current-voltage characteristics and impedance spectroscopy measurements performed on partially sulfur-containing thin films in sandwich structure ITO/sulfur-containing polymer/Al. The conduction mechanisms in these layers are identified to be a space-charge-limited current. The AC electrical transport of the sulfur-containing polymer is studied as a function of frequency (100 Hz-10 MHz) and temperature in impedance spectroscopy analyses. We interpreted Cole-Cole plots in terms of the equivalent circuit model as a single parallel resistance and a capacitance network in series with a relatively small resistance. The evolution of the electrical parameters deduced from fitting of the experimental data is discussed.

Subcritical wet air oxidation of organic solvents and chelating agents of the nuclear fuel

International Nuclear Information System (INIS)

Bachir, Souley

1999-01-01

This document deals with the environment control, more specially organic solvents and chelating agents destruction, employed in the nuclear industry. This work details the subcritical wet air oxidation process. Another part of the document deals with the possible coupling between this process and the biodegradation technic in the framework of the sewage sludges treatment. (A.L.B.)

Study on the Relation between the Mn/Al Mixed Oxides Composition and Performance of FCC Sulfur Transfer Agent

Directory of Open Access Journals (Sweden)

Ruiyu Jiang

2016-01-01

Full Text Available A sulfur transfer agent in catalysts can effectively reduce the emission of SO2 with minimum adverse effects on the catalytic cracking ability of the primary catalyst. In this paper, the composition and performance of sulfur transfer agents with different oxidative active components (such as Cu, Fe, Ni, Co, Ba, Zn and Cr were prepared by acid peptization technique and characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and N2 adsorption-desorption technique. The relationship between the composition and performance of the new sulfur transfer agents was investigated and the regeneration and recycling of the agents were performed. The results indicates that copper is a very good desulfurization active component. Moreover, the presence of CO has no significant effect on the absorption ability of SO2 by the sulfur transfer agent.

Mechanical properties of styrene-butadiene rubber cured by ionizing radiation in the presence of sulfur and polyfunctional agent

International Nuclear Information System (INIS)

Basfar, A.A.; Al-Harithy, F.A.; Abdel-Aziz, M.M.

1997-01-01

The mechanical Properties of Styrene-Butadiene Rubber (SBR) samples cured by a combination of sulfur and ionizing radiation in the presence of polyfunctional crosslinking agent were studied. SBR formulations containing various concentrations of trimethyl propane triacrylate (TMPTA) were irradiated at absorbed doses in the range of 35-200 kGy. The influence of TMPTA on the mechanical properties, solubility % and swelling % were investigated. The various formulations were compared at the same crosslink density as determined by 200% modulus (i.e. tensile strength at 200% elongation). The increase in TMPTA concentration has led to the decrease in the absorbed dose required to achieve full-cure conditions. Another set of SBR formulations containing partial levels of sulfur in the presence of the same TMPTA concentrations as the earlier formulations were irradiated at the same absorbed dose range. The presence of sulfur has further decreased the absorbed dose required to achieve full-cure conditions. Thermal stability of the two sets of SBR formulations as studied by Thermogravimetric Analyzer (TGA) and Differential Scanning Calorimeter (DSC) remained unchanged over the entire range of absorbed dose

Gadolinium retention after administration of contrast agents based on linear chelators and the recommendations of the European Medicines Agency

International Nuclear Information System (INIS)

Dekkers, Ilona A.; Roos, Rick; Molen, Aart J. van der

2018-01-01

The Pharmacovigilance Risk Assessment Committee (PRAC) of the European Medicines Agency (EMA) earlier this year recommended to suspend some marketing authorisations for Gadolinium Containing Contrast Agents (GCCAs) based on linear chelators due to the potential risk of gadolinium retention in the human body. These recommendations have recently been re-evaluated by EMA's Committee for Medicinal Products for Human Use (CHMP), and confirmed the final opinion of the European Medicines Agency. This editorial provides an overview of the available GCCAs and summarises the recent evidence of gadolinium retention. Moreover, a critical appraisal of the strengths and limitations of the scientific evidence currently available on gadolinium retention is given. (orig.)

Study on the mutagenic effects of a new chelating agent (7603) used for accelerating excretion of radionuclides

International Nuclear Information System (INIS)

Shen Binyuan; Luo Meichu; Zhen Guibao; Ruan Tianming; Feng Jialin; Cao Qunli

1989-01-01

The results of studies on the mutagenic effects of a new chelating agent, Suo An Quan (7603) or 5-methxlene Iminodiaeticaid Vanillin, was reported in this paper. For this agent, no mutagenesis was found by the reverse mutation test of Salmonella typhi munine (Amos test), the test of chromosome aberrations in Chinese hamster oocytes (CHO cells), and the test of micronucleus in polychromatic erythrocytes of the bone marrow in mice

Effect of the ultrasound-Fenton oxidation process with the addition of a chelating agent on the removal of petroleum-based contaminants from soil.

Science.gov (United States)

Li, Ying; Li, Fangmin; Li, Fanxiu; Yuan, Fuqian; Wei, Pingfang

2015-12-01

The effects of ultrasonic irradiation, the chelating agent modified Fenton reaction, and a combination of ultrasound and the Fenton method in removing petroleum contaminants from a soil were studied. The results showed that the contaminant removal rate of the Fenton treatment combined with an oxalic acid chelating agent was 55.6% higher than that without a chelating agent. The average removal rate of the contaminants using the ultrasound-Fenton treatment was 59.0% higher than that without ultrasonic treatment. A combination of ultrasound and an Fe(2+)/Fe(3+)-oxalate complex-modified Fenton reagent resulted in significantly higher removal rates of n-alkanes (C(n)H(2n+2), n Fenton method. The Fenton reaction and the ultrasound-Fenton treatment can unselectively remove multiple components of residual hydrocarbons and a number of benzene rings in polycyclic aromatic hydrocarbons. The chemistry of the heterocyclic compounds and the position and number of substituents can affect the degradation process.

Role of chelates in magnetic resonance imaging studies

Directory of Open Access Journals (Sweden)

Tripathi Laxmi

2009-01-01

Full Text Available Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient′s body. Magnetic resonance imaging (MRI is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

Sequestering agent for uranyl chelation: a new family of CAMS ligands

International Nuclear Information System (INIS)

Leydier, A.; Pellet-Rostaing, S.; Favre-Reguillon, A.; Lemaire, M.; Lecercle, D.; Taran, F.

2008-01-01

The synthesis of new dipodal bis-sulfo-catechol-amide uranophiles is presented. Their binding abilities for uranyl cation were determined by UV spectrophotometry in aqueous media under various pH conditions and further studied by 1 H NMR analysis of the resonance signal of both aromatic protons of the sulfo-catechol-amide groups. The results showed that the efficiency of these hydrosoluble chelating agents depends on the nature of the spacers. Each ligand shows a more or less pronounced affinity for uranium. The best receptor is the ligand CYCAMS 5d obtained as a mixture of cis/trans isomers, which achieves the best compromise between rigidity and steric hindrance. (authors)

Topical efficacy of dimercapto-chelating agents against lewisite-induced skin lesions in SKH-1 hairless mice

Energy Technology Data Exchange (ETDEWEB)

Mouret, Stéphane, E-mail: stephane.mouret@irba.fr [Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, Centre de Recherches du Service de Santé des Armées, 24 avenue Maquis du Grésivaudan, 38700 La Tronche (France); Wartelle, Julien; Emorine, Sandy; Bertoni, Marine; Nguon, Nina; Cléry-Barraud, Cécile [Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, Centre de Recherches du Service de Santé des Armées, 24 avenue Maquis du Grésivaudan, 38700 La Tronche (France); Dorandeu, Frédéric [Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, Centre de Recherches du Service de Santé des Armées, 24 avenue Maquis du Grésivaudan, 38700 La Tronche (France); Ecole du Val-de-Grâce, 1 place Alphonse Laveran, Paris (France); Boudry, Isabelle [Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, Centre de Recherches du Service de Santé des Armées, 24 avenue Maquis du Grésivaudan, 38700 La Tronche (France)

2013-10-15

Lewisite is a potent chemical warfare arsenical vesicant that can cause severe skin lesions. Today, lewisite exposure remains possible during demilitarization of old ammunitions and as a result of deliberate use. Although its cutaneous toxicity is not fully elucidated, a specific antidote exists, the British anti-lewisite (BAL, dimercaprol) but it is not without untoward effects. Analogs of BAL, less toxic, have been developed such as meso-2,3-dimercaptosuccinic acid (DMSA) and have been employed for the treatment of heavy metal poisoning. However, efficacy of DMSA against lewisite-induced skin lesions remains to be determined in comparison with BAL. We have thus evaluated in this study the therapeutic efficacy of BAL and DMSA in two administration modes against skin lesions induced by lewisite vapor on SKH-1 hairless mice. Our data demonstrate a strong protective efficacy of topical application of dimercapto-chelating agents in contrast to a subcutaneous administration 1 h after lewisite exposure, with attenuation of wound size, necrosis and impairment of skin barrier function. The histological evaluation also confirms the efficacy of topical application by showing that treatments were effective in reversing lewisite-induced neutrophil infiltration. This protective effect was associated with an epidermal hyperplasia. However, for all the parameters studied, BAL was more effective than DMSA in reducing lewisite-induced skin injury. Together, these findings support the use of a topical form of dimercaprol-chelating agent against lewisite-induced skin lesion within the first hour after exposure to increase the therapeutic management and that BAL, despite its side-effects, should not be abandoned. - Highlights: • Topically applied dimercapto-chelating agents reduce lewisite-induced skin damage. • One topical application of BAL or DMSA is sufficient to reverse lewisite effects. • Topical BAL is more effective than DMSA to counteract lewisite-induced skin damage.

The attachment of metal-chelating groups to proteins: tagging of albumin by diazonium coupling and use of the products as radiopharmaceuticals

International Nuclear Information System (INIS)

Leung, C.S.H.; Meares, C.F.; Goodwin, D.A.

1978-01-01

The ability to attach firmly chelated metal ions or powerful chelating agents to sites on biological molecules can enhance the utility of a number of physical techniques now used in the study of biological systems. A 'bifunctional' chelating agent, containing both an EDTA group and a diazonium group, has been prepared and coupled to human serum albumin. The extent of labeling under various conditions and the amino-acid sidechains labeled have been investigated. The reaction of protein-bound chelating groups with added metal ions has been studied, with the finding that only about 40-50% of these groups are available to bind metal ions. Proteolysis of the products leads to recovery of full metal-binding capacity. Properties of the products in vivo are discussed. (author)

One-Step Extraction of Antimony in Low Temperature from Stibnite Concentrate Using Iron Oxide as Sulfur-Fixing Agent

Directory of Open Access Journals (Sweden)

Yun Li

2016-07-01

Full Text Available A new process for one-step extraction of antimony in low temperature from stibnite concentrate by reductive sulfur-fixation smelting in sodium molten salt, using iron oxide as sulfur-fixing agent, was presented. The influences of molten salt addition and composition, ferric oxide dosage, smelting temperature and duration on extraction efficiency of antimony were investigated in details, respectively. The optimum conditions were determined as follows: 1.0 time stoichiometric requirement (α of mixed sodium salt (αsalt = 1.0, WNaCl:Wsalt = 40%, αFe2O3 = 1.0, Wcoke:Wstibnite = 40%, where W represents weight, smelting at 850 °C (1123 K for 60 min. Under the optimum conditions, the direct recovery rate of antimony can reach 91.48%, and crude antimony with a purity of 96.00% has been achieved. 95.31% of sulfur is fixed in form of FeS in the presence of iron oxide. Meanwhile, precious metals contained in stibnite concentrate are enriched and recovered comprehensively in crude antimony. In comparison to traditional antimony pyrometallurgical process, the smelting temperature of present process is reduced from 1150–1200 °C (1423–1473 K to 850–900 °C (1123–1173 K. Sulfur obtained in stibnite is fixed in FeS which avoids SO2 emission owing to the sulfur-fixing agent. Sodium salt can be regenerated and recycled in smelting system when the molten slag is operated to filter solid residue. The solid residue is subjected to mineral dressing operation to obtain iron sulfide concentrate which can be sold directly or roasted to regenerate into iron oxide.

Novel chelating agents for iron, manganese, zinc, and copper mixed fertilisation in high pH soil-less cultures.

Science.gov (United States)

López-Rayo, Sandra; Nadal, Paloma; Lucena, Juan J

2016-03-15

Studies about simultaneous fertilisation with several micronutrients have increased in recent years, as Fe, Mn and Zn deficiencies may appear in the same culture conditions. In fertigation, the replacement of sulfates by synthetic chelates is essential in areas with high pH irrigation water and substrates. Ethylenediamine-N-(2-hydroxyphenylacetic acid)-N'-(4-hydroxyphenylacetic acid) (o,p-EDDHA) and ethylenediamine disuccinic acid (EDDS) are novel chelating agents whose efficacy in simultaneous fertilisation of Zn, Mn and Cu is unknown. This work evaluates the effectiveness of both ligands compared to traditional ligands (EDTA, HEEDTA and DTPA) applied as micronutrient chelate mixtures to soybean and navy bean plants grown in soil-less cultures at high pH by analysing the SPAD and micronutrient nutritional status, including the Composition Nutritional Diagnosis (CND) analysis tool. The application of micronutrients using o,p-EDDHA was more effective in providing Mn and Zn than traditional ligands or sulfates. The application using EDDS increased the Zn nutrition. The results are well correlated with the chemical stability of the formulations. The combined application of Mn and Zn as o,p-EDDHA chelates can represent a more effective source than traditional chelates in micronutrient fertiliser mixtures in soil-less cultures at a high pH. © 2015 Society of Chemical Industry.

Reducing the potential for migration of radioactive waste: Aqueous thermal degradation of the chelating agent disodium EDTA

International Nuclear Information System (INIS)

Boles, J.S.; Ritchie, K.; Crerar, D.A.

1987-01-01

Ethylenediaminetetraacetic acid (EDTA), a common component of cleaning solutions used for decontamination of radioactive equipment, has been associated with increased migration of radionuclides into local groundwaters at some radwaste disposal sites. It has been proposed that predisposal thermal degradation of EDTA-containing aqueous solutions may reduce the potential for chelate-enhanced mobilization of radionuclides at these sites. Aqueous thermal degradation experiments with disodium EDTA have shown that the compound degrades rapidly at 200 0 C with an activation energy of 114.3 +- 7.87 kJ/mol, and forms the decomposition product methyliminodiacetic acid (MIDA). A comparison of the values for stability constants of transition metal and actinide complexes with EDTA, MIDA, and two other reported degradation products, indicates that the chelating efficiency of the degradation products is 6 to 22 orders of magnitude lower than that of EDTA at 25 0 C. It is concluded that aqueous thermal degradation should significantly reduce the overall chelating efficiency of EDTA-containing solutions

Effect of the tether on the Mg(II), Ca(II), Cu(II) and Fe(III) stability constants and pM values of chelating agents related to EDDHA.

Science.gov (United States)

Sierra, Miguel A; Gómez-Gallego, Mar; Alcázar, Roberto; Lucena, Juan J; Yunta, Felipe; García-Marco, Sonia

2004-11-07

The effect of the length and the structure of the tether on the chelating ability of EDDHA-like chelates have not been established. In this work, PDDHA (propylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid), BDDHA (butylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid) and XDDHA (p-xylylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid) have been obtained and their chemical behaviour has been studied and compared with that of EDDHA following our methodology. The purity of the chelating agents, and their protonation, Ca(II), Mg(II), Fe(III) and Cu(II) stability constants and pM values have been determined. The stability constants and pM values indicate that EDDHA forms the most stable chelates followed by PDDHA. However, the differences among the pFe values are small when a nutrient solution is used, and in these conditions the XDDHA/Fe(III) chelate is the most stable. The results obtained in this work indicate that all the chelating agents studied can be used as iron chlorosis correctors and they can be applied to soil/plant systems.

Mechanisms of oxide dissolution by acid chelating agents

International Nuclear Information System (INIS)

Blesa, M.A.; Maroto, A.J.G.

1982-01-01

In this paper, the different possible rate controlling processes in the dissolution of metallic oxides are examined. In particular, the following situations are assessed: mass-transfer control; coupling of mass-transfer and reactions at the interface; interface equilibration with the solution; various interface disruption and reconstruction phenomena. For each of the above mentioned cases, the influence of variables such as reagent concentration, temperature, pH, fluid hydrodynamics and general and specific catalysts is discussed. Depending upon the particular situation it is found that a more rational basis for the development of reagent is given by these considerations. The influence of chelating agents on both the thermodynamics and kinetics of the process is discussed, and the results of experimental studies in batch on magnetite and various ferrites are presented and discussed. For this purpose, several reagents were studied, including some very effective ones like thioglycolic acid, and others commonly used in actual decontamination, like ethylenediaminetetraacetic acid and oxalic acid. The relation to other (reductive) chemical decontamination procedures is discussed. The relevance of these studies to decontamination of metallic surfaces is discussed

Feasibility of tetracycline, a common antibiotic, as chelating agent for spectrophotometric determination of UO22+ after cloud point extraction

International Nuclear Information System (INIS)

Esra Bagda; Ebru Yabas; Nihat Karakus

2014-01-01

A cloud point extraction (CPE) procedure was presented for the preconcentration of UO 2 2+ ion in different water samples. Tetracycline (TC) is the second most widely used antibiotics in the world and is used as chelating agent. To the best of our knowledge, this is the first work that an antibiotic is used as a chelating agent for CPE of UO 2 2+ . Besides, the use of TC as complexing agent provides excellent chelating features. TC molecule has large numbers of functional groups (adjacent hydroxyl oxygen atoms and cyclohexanone oxygen atoms, amide groups) which can form stable complex with UO 2 2+ . After complexation with TC, UO 2 2+ ions were quantitatively recovered in Triton X-100 after cooling in the ice bath. 3.0 mL of acetate buffer was added to the surfactant-rich phase prior to its analysis by UV-Vis spectrophotometer. The influence of analytical parameters including pH, buffer volume, TC, Triton X-100 concentrations, bath temperature, incubation time were optimized. The effect of the matrix ions on the recovery of UO 2 2+ ions was investigated. The limit of detection was 0.0746 μg mL -1 along with enrichment factor of 14.3 with a R.S.D. of 3.6 %. The proposed procedure was applied to the analysis of various environmental water samples. On the other hand, the electronic distribution of TC molecule is investigated with their frontier molecular orbital density distributions. (author)

Mustard gas or sulfur mustard: an old chemical agent as a new terrorist threat.

Science.gov (United States)

Wattana, Monica; Bey, Tareg

2009-01-01

Sulfur mustard is a member of the vesicant class of chemical warfare agents that causes blistering to the skin and mucous membranes. There is no specific antidote, and treatment consists of systematically alleviating symptoms. Historically, sulfur mustard was used extensively in inter-governmental conflicts within the trenches of Belgium and France during World War I and during the Iran-Iraq conflict. Longitudinal studies of exposed victims show that sulfur mustard causes long-term effects leading to high morbidity. Given that only a small amount of sulfur mustard is necessary to potentially cause an enormous number of casualties, disaster-planning protocol necessitates the education and training of first-line healthcare responders in the recognition, decontamination, triage, and treatment of sulfur mustard-exposed victims in a large-scale scenario.

Investigation of a potential macromolecular MRI contrast agent prepared from PPI (G = 2, polypropyleneimine, generation 2) dendrimer bifunctional chelates

Science.gov (United States)

Wang, Jianxin Steven

The long-term objective is to develop magnetic resonance (MR) contrast agents that actively and passively target tumors for diagnosis and therapy. Many diagnostic imaging techniques for cancer lack specificity. A dendrimer based magnetic resonance imaging contrast agent has been developed with large proton relaxation enhancements and high molecular relaxivities. A new type of linear dendrimer based MRI contrast agent that is built from the polypropyleneimine and polyamidoamine dendrimers in which free amines have been conjugated to the chelate DTPA, which further formed the complex with Gadolinium (Gd) was studied. The specific research goals were to test the hypothesis that a linear chelate with macromolecular agents can be used in vitro and in vivo. This work successfully examined the adequacy and viability of the application for this agent in vitro and in vivo. A small animal whole body counter was designed and constructed to allow us to monitor biodistribution and kinetic mechanisms using a radioisotope labeled complex. The procedures of metal labeling, separation and purification have been established from this work. A biodistribution study has been performed using radioisotope induced organ/tissue counting and gamma camera imaging. The ratio of percentage of injected dose per gram organ/tissue for kidney and liver is 3.71 from whole body counter and 3.77 from the gamma camera. The results suggested that retention of Gd (III) is too high and a more kinetically stable chelate should be developed. The pharmacokinetic was evaluated in the whole animal model with the whole body clearance, and a kinetics model was developed. The pharmacokinetic results showed a bi-exponential decay in the animal model with two component excretion constants 1.43e(-5) and 0.0038511, which give half-lives of 3 hours and 33.6 days, respectively. Magnetic resonance imaging of this complex resulted in a 52% contrast enhancement in the rat kidney following the agents' administration in

Radiopharmaceutical chelates and method of external imaging

International Nuclear Information System (INIS)

1976-01-01

The preparation of the following chemicals is described: chelates of technetium-99m, cobalt-57, gallium-67, gallium-68, indium-111 or indium-113m and a substituted iminodiacetic acid or an 8-hydroxyquinoline useful as a radiopharmaceutical external imaging agent. The compounds described are suitable for intravenous injection, have an excellent in vivo stability and are good organ seekers. Tin(II) choride or other tin(II) compounds are used as chelating agents

Chelating agent-assisted electrokinetic removal of cadmium, lead and copper from contaminated soils

International Nuclear Information System (INIS)

Giannis, Apostolos; Nikolaou, Aris; Pentari, Despina; Gidarakos, Evangelos

2009-01-01

An integrated experimental program was conducted to remove Cd, Pb and Cu from contaminated soil. The chelate agents nitrilotriacetic acid (NTA), diethylenetriamine pentaacetic acid (DTPA) and ethyleneglycol tetraacetic acid (EGTA) were used as washing solutions under different pH conditions and concentrations. Results showed that the extraction efficiency for Cd in decreasing order was NTA > EGTA > DTPA, while for Pb and Cu it was DTPA > NTA > EGTA. The use of higher chelate concentrations did not necessarily result in greater extraction efficiency. Electrokinetic remediation was applied by conditioning anolyte-catholyte pH to neutral values in order to avoid any potential alterations to the physicochemical soil properties. The removal efficiency for Cd was 65-95%, for Cu 15-60%, but for Pb was less than 20%. The phytotoxicity of the treated soil showed that the soil samples from the anode section were less phytotoxic than the untreated soil, but the phytotoxicity was increased in the samples from the cathode section. - Cadmium, lead and copper were extracted from contaminated soil by integrated electrokinetic and soil washing studies.

Chelating agent-assisted electrokinetic removal of cadmium, lead and copper from contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Giannis, Apostolos, E-mail: apostolos.giannis@enveng.tuc.g [Laboratory of Toxic and Hazardous Waste Management, Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece); Nikolaou, Aris [Laboratory of Toxic and Hazardous Waste Management, Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece); Pentari, Despina [Laboratory of Inorganic and Organic Geochemistry and Organic Petrography, Department of Mineral Resources Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece); Gidarakos, Evangelos, E-mail: gidarako@mred.tuc.g [Laboratory of Toxic and Hazardous Waste Management, Department of Environmental Engineering, Technical University of Crete, Politechnioupolis, Chania 73100 (Greece)

2009-12-15

An integrated experimental program was conducted to remove Cd, Pb and Cu from contaminated soil. The chelate agents nitrilotriacetic acid (NTA), diethylenetriamine pentaacetic acid (DTPA) and ethyleneglycol tetraacetic acid (EGTA) were used as washing solutions under different pH conditions and concentrations. Results showed that the extraction efficiency for Cd in decreasing order was NTA > EGTA > DTPA, while for Pb and Cu it was DTPA > NTA > EGTA. The use of higher chelate concentrations did not necessarily result in greater extraction efficiency. Electrokinetic remediation was applied by conditioning anolyte-catholyte pH to neutral values in order to avoid any potential alterations to the physicochemical soil properties. The removal efficiency for Cd was 65-95%, for Cu 15-60%, but for Pb was less than 20%. The phytotoxicity of the treated soil showed that the soil samples from the anode section were less phytotoxic than the untreated soil, but the phytotoxicity was increased in the samples from the cathode section. - Cadmium, lead and copper were extracted from contaminated soil by integrated electrokinetic and soil washing studies.

Vascular-targeted photodynamic therapy with BF2-chelated Tetraaryl-Azadipyrromethene agents: a multi-modality molecular imaging approach to therapeutic assessment.

LENUS (Irish Health Repository)

Byrne, A T

2009-11-03

Photodynamic therapy (PDT) is a treatment modality for a range of diseases including cancer. The BF(2)-chelated tetraaryl-azadipyrromethenes (ADPMs) are an emerging class of non-porphyrin PDT agent, which have previously shown excellent photochemical and photophysical properties for therapeutic application. Herein, in vivo efficacy and mechanism of action studies have been completed for the lead agent, ADMP06.

Modeling the chelation of As(III) in lewisite by dithiols using density functional theory and solvent-assisted proton exchange.

Science.gov (United States)

Harper, Lenora K; Bayse, Craig A

2015-12-01

Dithiols such as British anti-lewisite (BAL, rac-2,3-dimercaptopropanol) are an important class of antidotes for the blister agent lewisite (trans-2-chlorovinyldichloroarsine) and, more generally, are chelating agents for arsenic and other toxic metals. The reaction of the vicinal thiols of BAL with lewisite through the chelation of the As(III) center has been modeled using density functional theory (DFT) and solvent-assisted proton exchange (SAPE), a microsolvation method that uses a network of water molecules to mimic the role of bulk solvent in models of aqueous phase chemical reactions. The small activation barriers for the stepwise SN2-type nucleophilic attack of BAL on lewisite (0.7-4.9kcal/mol) are consistent with the favorable leaving group properties of the chloride and the affinity of As(III) for soft sulfur nucleophiles. Small, but insignificant, differences in activation barriers were found for the initial attack of the primary versus secondary thiol of BAL and the R vs S enantiomer. An examination of the relative stability of various dithiol-lewisite complexes shows that ethanedithiols like BAL form the most favorable chelation complexes because the angles formed in five-membered ring are most consistent with the hybridization of As(III). More obtuse S-As-S angles are required for larger chelate rings, but internal As⋯N or As⋯O interactions can enhance the stability of moderate-sized rings. The low barriers for lewisite detoxification by BAL and the greater stability of the chelation complexes of small dithiols are consistent with the rapid reversal of toxicity demonstrated in previously reported animal models. Copyright © 2015 Elsevier Inc. All rights reserved.

Quantitative property-property relationship (QPPR) approach in predicting flotation efficiency of chelating agents as mineral collectors.

Science.gov (United States)

Natarajan, R; Nirdosh, I; Venuvanalingam, P; Ramalingam, M

2002-07-01

The QPPR approach has been used to model cupferrons as mineral collectors. Separation efficiencies (Es) of these chelating agents have been correlated with property parameters namely, log P, log Koc, substituent-constant sigma, Mullikan and ESP derived charges using multiple regression analysis. Es of substituted-cupferrons in the flotation of a uranium ore could be predicted within experimental error either by log P or log Koc and an electronic parameter. However, when a halo, methoxy or phenyl substituent was in para to the chelating group, experimental Es was greater than the predicted values. Inclusion of a Boolean type indicative parameter improved significantly the predictability power. This approach has been extended to 2-aminothiophenols that were used to float a zinc ore and the correlations were found to be reasonably good.

The Quantitation of Sulfur Mustard By-Products, Sulfur-Containing Herbicides, and Organophosphonates in Soil and Concrete

Energy Technology Data Exchange (ETDEWEB)

Tomkins, B.A., Sega, G.A. [Oak Ridge National Lab., TN (United States)], Macnaughton, S.J. [Microbial Insights, Inc., Rockford, TN (United States)

1997-12-31

Over the past fifty years, the facilities at Rocky Mountain Arsenal have been used for the manufacturing, bottling, and shipping sulfur- containing herbicides, sulfur mustard, and Sarin. There is a need for analytical methods capable of determining these constituents quickly to determine exactly how specific waste structural materials should be handled, treated, and landfilled.These species are extracted rapidly from heated samples of soil or crushed concrete using acetonitrile at elevated pressure, then analyzed using a gas chromatograph equipped with a flame photometric detector. Thiodiglycol, the major hydrolysis product of sulfur mustard, must be converted to a silylated derivative prior to quantitation. Detection limits, calculated using two statistically-unbiased protocols, ranged between 2-13 micrograms analyte/g soil or concrete.

Gd (III) chelates adsorbed on TiO2 nanoparticles - promising MRI contrast agent

International Nuclear Information System (INIS)

Rehor, Ivan; Lukes, Ivan; Peters, Joop A.; Jirak, Daniel

2009-01-01

Full text: The project deals with a new contrast agent (CA) for magnetic resonance imaging (MRI). The CA consists of two main parts - diamagnetic core (TiO 2 nanoparticle) and Gd (III) chelates grafted on its surface. The presence of the nanoparticle core is responsible for significant increase of r1 millimolar relaxivity (which corresponds to the efficiency of the CA) due to the slowing down the rotation of the complex in solution. It also affects the biodistribution characteristics of the CA - the ability to penetrate through cell membranes is well known for nanoparticles, making them useful for cell labeling. The structure of the chelate is derived from DOTA ligand, whose Gd (III) complexes are commercially used as MRI CA in human medicine. The connection of the complex to the surface is realized via penylphosphonate, which is attached to the pendant arm of the ligand. Strong interaction of the phosphonate with the TiO 2 surface results in the full surface coverage. The complexation and MRI properties of Gd chelate were studied and exhibit analogy to the complexes of DOTA, The millimolar relaxivity (r1) of the Gd (III) complex significantly increases upon adsorption on the TiO 2 nanoparticles. PVA was added to the colloidal solutions of CA to stabilize them under biological conditions and such stabilized CA was utilized for MRI visualization of rat pancreatic islets (P1). The labeled islets were detected on MR images as hyperintense area and therefore our CA seems to be promising material for cellular MRI

Synthesis and Studies of Sulfur-Containing Heterocyclic Molecules for Molecular Electronics

DEFF Research Database (Denmark)

Mazzanti, Virginia

This work describes the synthesis and studies of sulfur containing π conjugated heterocycles, which are considered interesting motifs in the field of molecular electronics. The first project, which is covered in Chapter 1, concerns the functionalization of tetracycle dibenzo[bc,fg][1,4]dithiapent......This work describes the synthesis and studies of sulfur containing π conjugated heterocycles, which are considered interesting motifs in the field of molecular electronics. The first project, which is covered in Chapter 1, concerns the functionalization of tetracycle dibenzo[bc,fg][1......,4]dithiapentalene (DDP). Attempts to prepare the S-O analog are also discussed. Chapter 2, focuses upon the studies performed on DDP and other sulfur containing π conjugated organic molecules. Organic Field Effect Transistor devices were fabricated and their performances were evaluated. Chapter 3 entails...... the synthesis of dimeric structures of redox active system tetrathiafulvalene (TTF). Molecules with different conjugation pathways bridging two TTFs were synthesized and studied using CV and DPV in order to probe the electronic interaction between these two redox units. The last aspect of this thesis, which...

Synthesis of sulfur-containing lubricant additives on the basis of fatty acid ethyl esters

Directory of Open Access Journals (Sweden)

Iurii S. Bodachivskyi

2016-12-01

Full Text Available The study reveals an energy-, resource- and eco-friendly method for preparation of sulfur-containing lubricant additives via interaction of fatty acid ethyl esters of rapeseed oil with elemental sulfur. The structure of synthesized compounds under various reactants ratio (5–50 wt.% of sulfur, duration (30–240 min and temperature of the process (160–215°С was investigated using various analytical techniques. According to the established data, aside from addition to double bonds, the side reaction of hydrogen substitution at α-methylene groups near these bonds occurs and induces the formation of conjugated systems and chromophoric sulfur-rich derivatives. Also, we found that increase of process duration evokes growth of polysulfane chains, in contrast to the raise of temperature, which leads to the formation of sulfur-containing heterocycles and hydrogen sulfide, as a result of elimination. Influence of accelerators on sulfurization of fatty acid ethyl esters was also examined. The most effective among them are mixtures of zinc dibutyldithiocarbamate with zinc oxide or stearic acid, which soften synthesis conditions and doubly decrease duration of the high-temperature stage. In addition, sulfur-containing compositions of ethyl esters and α-olefins, vulcanized esters by benzoyl peroxide, nonylphenols and zinc dinonylphenyldithiophosphate were designed. The study identified that lithium lubricant with sulfurized vulcanized esters provides improved tribological properties, in comparison with base lubricant or lubricant with the non-modified product.

Potent heme-degrading action of antimony and antimony-containing parasiticidal agents.

Science.gov (United States)

Drummond, G S; Kappas, A

1981-02-01

The ability of antimony and antimony-containing parasiticidal agents to enhance the rate of heme degradation in liver and kidney was investigated. Trivalent antimony was shown to be an extremely potent inducer of heme oxygenase, the initial and rate-limiting enzyme in heme degradation, in both organs, whereas the pentavalent form was a weak inducer of this enzyme. The ability of antimony to induce heme oxygenase was dose-dependent, independent of the salt used, and not a result of a direct activation of the enzyme in vitro. Concomitant with heme oxygenase induction by antimony, microsomal heme and cytochrome P-450 contents decreased, the cyto-chrome P-450-dependent mixed function oxidase system was impaired, and delta-ami-nolevulinate synthase (ALAS), the rate-limiting enzyme of heme synthesis, underwent the sequential changes-initial inhibition followed by rebound induction-usually associated with the administration of transition elements such as cobalt. Antimony induction of heme oxygenase however, unlike the enzyme induction elicited by cobalt, was not prevented either by cysteine administered orally or as a cysteine metal complex, or by simultaneous zinc administration. Desferoxamine also did not block heme oxygenase induction by antimony, but this chelator did prevent the rebound increase in ALAS activity associated with antimony or cobalt treatment. Antimony-containing parasiticidal drugs were also potent inducers of heme oxygenase in liver and kidney. The heme degradative action of these drugs may be related in part to the jaundice commonly associated with the prolonged therapeutic use of these agents. The heme-oxygenase-inducing action of antimony-containing parasiticidal drugs is a newly defined biological property of these compounds. The relation between the parasiticidal and the heme-oxygenase-inducing actions of such drugs is unknown. However, certain parasites contain hemoproteins or require heme compounds during their life cycle. It may therefore be

High Mass-Loading of Sulfur-Based Cathode Composites and Polysulfides Stabilization for Rechargeable Lithium/Sulfur Batteries

International Nuclear Information System (INIS)

Hara, Toru; Konarov, Aishuak; Mentbayeva, Almagul; Kurmanbayeva, Indira; Bakenov, Zhumabay

2015-01-01

Although sulfur has a high theoretical gravimetric capacity, 1672 mAh/g, its insulating nature requires a large amount of conducting additives: this tends to result in a low mass-loading of active material (sulfur), and thereby, a lower capacity than expected. Therefore, an optimal choice of conducting agents and of the method for sulfur/conducting-agent integration is critically important. In this paper, we report that the areal capacity of 4.9 mAh/cm 2 was achieved at sulfur mass loading of 4.1 mg/cm 2 by casting sulfur/polyacrylonitrile/ketjenblack (S/PAN/KB) cathode composite into carbon fiber paper. This is the highest value among published/reported ones even though it does not contain expensive nanosized carbon materials such as carbon nanotubes, graphene, or graphene derivatives, and competitive enough with the conventional LiCoO 2 -based cathodes (e.g., LiCoO 2 , <20 mg/cm 2 corresponding to <2.8 mAh/cm 2 ). Furthermore, the combination of sulfur/PAN-based composite and PAN-based carbon fiber paper enabled the sulfur-based composite to be used even in carbonate-based electrolyte solution that many lithium/sulfur battery researchers avoid the use of it because of severer irreversible active material loss than in electrolyte solutions without carbonate-based solutions, and even at the highest mass-loading ever reported (the more sulfur is loaded, the more decomposed sulfides deposit at an anode surface).

Monochloro non-bridged half-metallocene-type zirconium complexes containing phosphine oxide-(thio)phenolate chelating ligands as efficient ethylene polymerization catalysts.

Science.gov (United States)

Tang, Xiao-Yan; Wang, Yong-Xia; Liu, San-Rong; Liu, Jing-Yu; Li, Yue-Sheng

2013-01-14

A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'Zr[X-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)](2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16°] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 °C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study.

Uranium(VI) adsorption properties of a chelating resin containing polyamine-substituted methylphosphonic acid moiety

International Nuclear Information System (INIS)

Matsuda, Masaaki; Akiyoshi, Yoshirou

1991-01-01

Uranium(VI) adsorption and desorption properties of a chelating resin containing polyamine-substituted methylphosphonic acid moiety of 2.29 mmol/g-resin (APA) were examined. Uranium(VI) adsorption properties of several ion exchange resins and extractant agents which were known as excellent adsorbents for uranium(VI), were examined together for a comparison with those of APA. Uranium(VI) adsorption capacity of APA at the concentration of 100 mg·dm -3 -uranium(VI) in 100 g·dm -3 -H 2 SO 4 aq. soln., 190 g·dm -3 -H 3 PO 4 aq. soln. and uranium enriched sea water, was 0.2, 0.05 and 0.05 mmol·g -1 respectively. The adsorption capacity of APA for uranium(VI) in these solutions was larger than that of another adsorbents, except the adsorption of uranium(VI) in enriched sea water on ion exchange resin containing phosphoric acid moiety (adsorption capacity ; 0.2 mmol·g -1 ). Uranium(VI) adsorption rate on APA was high and the relation between treatment time (t : min) and uranium(VI) concentration (y : mg·dm -3 ) in 100 g·dm -3 H 2 SO 4 aq. soln. after treatment, was shown as following equation, y=20 0.048t+1.90 (0≤t≤30). The adsorbed uranium(VI) on APA was able to be eluted with a mixed aq. soln. of hydrogen peroxide and sodium hydroxide and also was able to be eluted with an aq. alkaline soln. dissolved reduction agents such as sodium sulfite and hydrazine. From these results, it was thought that uranium(VI) adsorbed on APA was eluted due to the reduction to uranium(VI) by these eluents. (author)

Use of non-hyperaccumulator plant species for the phytoextraction of heavy metals using chelating agents

Directory of Open Access Journals (Sweden)

Lucas Anjos Souza

2013-08-01

Full Text Available Soil contamination by heavy metals is a challenge faced by many countries, and engineering technologies to solve this problem are expensive and can cause negative impacts on the environment. One way to minimise the levels of heavy metals in the soil is to use plants that can absorb and accumulate heavy metals into harvestable parts, a process called phytoextraction. Typical plant species used in research involving phytoextraction are heavy metal hyperaccumulators, but plants from this group are not good biomass producers and grow more slowly than most species; thus, they have an important role in helping scientists understand the mechanisms involved in accumulating high amounts of heavy metals without developing symptoms or dying. However, because of their slow growth, it is not practical to use these species for phytoextraction. An alternative approach is to use non-hyperaccumulator plants assisted by chelating agents, which may improve the ability of plants to accumulate more heavy metals than they would naturally. Chelating agents can be synthetic or organic acids, and the advantages and disadvantages of their use in improving the phytoextraction potential of non-hyperaccumulator plants are discussed in this article. We hope to draw attention to ways to improve the phytoextraction potential of non-hyperaccumulator plants that produce a large amount of biomass and to stimulate more research on phytoextraction-inducing substances.

Assessment of a gel-type chelating preparation containing 1-hydroxyethylidene-1, 1-bisphosphonate.

Science.gov (United States)

Girard, S; Paqué, F; Badertscher, M; Sener, B; Zehnder, M

2005-11-01

To test an aqueous gel containing 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) regarding its interactions with sodium hypochlorite, its calcium binding capacity, and its potential in preventing the formation of a smear layer when used in conjunction with rotary root canal preparation. The experimental aqueous gel consisted of (w/v) 2% alginate, 3% aerosil, 10% Tween 80 and 18% HEBP. Interactions of gel components with hypochlorite were assessed using iodometric titration and monochromatic ultraviolet spectrometry. Two commercial paste-type chelators containing ethylenediaminetetraacetic acid (EDTA) and peroxide (RC-Prep and Glyde) served as controls. Calcium-binding capacities were measured in mixtures with a Ca2+ standard solution buffered at pH 10 using a calcium-selective measuring chain. Finally, root canals of 16 extracted single-rooted premolars per group were instrumented using ProFile instruments dipped in the experimental gel, RC-Prep, or nothing. Additionally, canals were rinsed with 10 mL of a 1% NaOCl solution during/after preparation. Smear scores in instrumented teeth were monitored using scanning electron microscopy. None of the experimental gel components showed short-term interactions with hypochlorite, whilst EDTA, peroxide, RC-Prep and Glyde immediately reduced the hypochlorite in solution. The experimental gel chelated 30 mg Ca2+ g-1, compared with 16 mg Ca2+ g-1 and 11 mg Ca2+ g-1 chelated by RC-Prep and Glyde respectively. Smear scores obtained with the experimental gel were significantly (P<0.05) lower than with RC-Prep in coronal and middle root thirds, whilst no differences were observed in apical root thirds. Under the conditions of this study, an HEBP gel appeared advantageous over currently available products.

Mesoporous organosilica nanotubes containing a chelating ligand in their walls

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiao; Goto, Yasutomo; Maegawa, Yoshifumi; Inagaki, Shinji, E-mail: inagaki@mosk.tytlabs.co.jp [Toyota Central R and D Laboratories, Inc., Nagakute, Aichi 480-1192 (Japan); Japan Science and Technology Agency (JST)/ACT-C, Nagakute, Aichi, 480-1192 (Japan); Ohsuna, Tetsu [Toyota Central R and D Laboratories, Inc., Nagakute, Aichi 480-1192 (Japan)

2014-11-01

We report the synthesis of organosilica nanotubes containing 2,2′-bipyridine chelating ligands within their walls, employing a single-micelle-templating method. These nanotubes have an average pore diameter of 7.8 nm and lengths of several hundred nanometers. UV-vis absorption spectra and scanning transmission electron microscopy observations of immobilized nanotubes with an iridium complex on the bipyridine ligands showed that the 2,2′-bipyridine groups were homogeneously distributed in the benzene-silica walls. The iridium complex, thus, immobilized on the nanotubes exhibited efficient catalytic activity for water oxidation using Ce{sup 4+}, due to the ready access of reactants to the active sites in the nanotubes.

Regeneration of Three-Way Automobile Catalysts using Biodegradable Metal Chelating Agent – S, S-Ethylenediamine Disuccinic Acid (S, S-EDDS)

Science.gov (United States)

Regeneration of the activity of three-way catalytic converters (TWCs) was tested for the first time using a biodegradable metal chelating agent (S, S. Ethylenediamine disuccinic acid (S, S-EDDS). The efficiency of this novel environmentally friendly solvent in removing various c...

Selectivity in extraction of copper and indium with chelate extractants

International Nuclear Information System (INIS)

Zivkovic, D.

2003-01-01

Simultaneous extraction of copper and indium with chelate extractants (LIX84 and D2E11PA) was described. Stechiometry of metal-organic complexes examined using the method of equimolar ratios resulted in CuR 2 and InR 3 forms of hydrophobic extracting species. A linear correlation was obtained between logarithm of distribution coefficients and chelate agents and pH, respectively. Selectivity is generally higher with higher concentrations of chelate agents in the organic phase, and is decreased with increase of concentration of hydrogen ions in feeding phase. (Original)

Synthesis of novel bifunctional chelators and their use in preparing monoclonal antibody conjugates for tumor targeting

International Nuclear Information System (INIS)

Westerberg, D.A.; Carney, P.L.; Rogers, P.E.; Kline, S.J.; Johnson, D.K.

1989-01-01

Bifunctional derivatives of the chelating agents ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, in which a p-isothiocyanatobenzyl moiety is attached at the methylene carbon atom of one carboxymethyl arm, was synthesized by reductive alkylation of the relevant polyamine with (p-nitrophenyl)pyruvic acid followed by carboxymethylation, reduction of the nitro group, and reaction with thiophosgene. The resulting isothiocyanate derivatives reacted with monoclonal antibody B72.3 to give antibody-chelator conjugates containing 3 mol of chelator per mole of immunoglobulin, without significant loss of immunological activity. Such conjugates, labeled with the radioisotopic metal indium-111, selectively bound a human colorectal carcinoma implanted in nude mice when given intravenously. Uptake into normal tissues was comparable to or lower than that reported for analogous conjugates with known bifunctional chelators. It is concluded that substitution with a protein reactive group at this position in polyaminopolycarboxylate chelators does not alter the chelating properties of these molecules to a sufficient extent to adversely affect biodistribution and thus provides a general method for the synthesis of such chelators

Sulfur-containing components of gamma-irradiated garlic bulbs

International Nuclear Information System (INIS)

Joongho Kwon; Jonguck Choi; Hyungsik Yoon

1989-01-01

Sulfur-containing components associated with garlic flavors were investigated to determine the effect of γ-irradiation at 0.1Gy on the quality of garlic bulbs (Allium sativum L.) during storage at 3±1 0 C and 80±5% RH for 10 months. Irradiation treatment had no influence on the amount of total sulfur and thiosulfinate of stored garlic for 10 months, while the storage period brought about a significant reduction (P < 0.05) in the content of both components after the 6-8th month of storage compared with that at the beginning of storage period. The identity of irradiated alliin (S-allyl-L-cysteine sulfoxide) at sprout-inhibition dose was confirmed according to thin-layer chromatography, i.r. and NMR spectroscopy data. (author)

Sulfur-containing components of gamma-irradiated garlic bulbs

Science.gov (United States)

Kwon, Joong-Ho; Choi, Jong-Uck; Yoon, Hyung-Sik

Sulfur-containing components associated with garlic flavors were investigated to determine the effect of γ-irradiation at 0.1 kGy on the quality of garlic bulbs ( Allium sativum L.) during storage at 3±1°C and 80±5% RH for 10 months. Irradiation treatment had no influence on the amount of total sulfur and thiosulfinate of stored garlic for 10 months, while the storage period brought about a significant reduction ( P<0.05) in the content of both components after the 6-8th month of storage compared with that at the beginning of storage period. The identity of irradiated alliin ( S-allyl- L-cysteine sulfoxide) at sprout-inhibition dose was confirmed according to thin-layer chromatography, i.r. and NMR spectroscopy data.

Effects of solvent and chelating agent on synthesis of solid oxide fuel cell perovskite, La0.8Sr0.2CrO3-δ

International Nuclear Information System (INIS)

Lee, Byoung I.; Gupta, Ravindra K.; Whang, Chin M.

2008-01-01

Effects of solvent and chelating agent on synthesis of La 0.8 Sr 0.2 CrO 3-δ perovskite are reported. Samples are synthesized using a solvent (ethylene glycol or 2-methoxyethanol) and a chelating agent (acetylacetone, citric acid or ethylene diamine tetraacetic acid) by polymeric-gel method, and characterized by X-ray diffractometry and Fourier-transform infrared spectroscopy. Citric acid to metal cations molar ratio (Rc) is varied for ethylene glycol-citric acid system. Samples are mainly orthorhombic perovskite. SrCrO 4 is appeared as a secondary phase and found to be the lowest for ethylene glycol-citric acid combination with Rc equal to 7. Crystallographic parameters of perovskite phase are determined and compared with those of LaCrO 3 . A mechanism employing a partial-charge model, chelating effect and solvent-cage effect is proposed to explain the results. Effect of sintering temperature on phase, relative density and morphology of samples prepared using ethylene glycol and citric acid (Rc = 7) is also reported

Sulfur polymer cement, a solidification and stabilization agent for radioactive and hazardous wastes

International Nuclear Information System (INIS)

Darnell, R.G.

1993-01-01

Sulfur polymer cement (SPC) is made by reacting 95% sulfur with 2.5 % dicyclopentadiene and 2.5% cyclopentadiene oligomers, to produce a product that is much better than unmodified sulfur. SPC is being tested as a solidifying and stabilizing agent for low-level radioactive and hazardous wastes. Heavy loadings (5 wt%) of eight toxic metals were combined individually with SPC and 7 wt% sodium sulfide nonahydrate. The leach rates for mercury, lead, chromium and silver oxides were reduced by six orders of magnitude, while those of arsenic and barium were reduced by four. SPC is good for stabilizing incinerator ash. Ion-exchange resins can be stabilized with SPC after heat treatment with asbestos or diatomite at 220-250 deg C. 19 refs

14 CFR 29.1199 - Extinguishing agent containers.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Extinguishing agent containers. 29.1199....1199 Extinguishing agent containers. (a) Each extinguishing agent container must have a pressure relief to prevent bursting of the container by excessive internal pressures. (b) The discharge end of each...

14 CFR 25.1199 - Extinguishing agent containers.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Extinguishing agent containers. 25.1199....1199 Extinguishing agent containers. (a) Each extinguishing agent container must have a pressure relief to prevent bursting of the container by excessive internal pressures. (b) The discharge end of each...

Characterization of the effect of serum and chelating agents on Staphylococcus aureus biofilm formation; chelating agents augment biofilm formation through clumping factor B

Science.gov (United States)

Abraham, Nabil Mathew

Staphylococcus aureus is the causative agent of a diverse array of acute and chronic infections, and some these infections, including infective endocarditis, joint infections, and medical device-associated bloodstream infections, depend upon its capacity to form tenacious biofilms on surfaces. Inserted medical devices such as intravenous catheters, pacemakers, and artificial heart valves save lives, but unfortunately, they can also serve as a substrate on which S. aureus can form a biofilm, attributing S. aureus as a leading cause of medical device-related infections. The major aim of this work was take compounds to which S. aureus would be exposed during infection and to investigate their effects on its capacity to form a biofilm. More specifically, the project investigated the effects of serum, and thereafter of catheter lock solutions on biofilm formation by S. aureus. Pre-coating polystyrene with serum is frequently used as a method to augment biofilm formation. The effect of pre-coating with serum is due to the deposition of extracellular matrix components onto the polystyrene, which are then recognized by MSCRAMMs. We therefore hypothesized that the major component of blood, serum, would induce biofilm formation. Surprisingly, serum actually inhibited biofilm formation. The inhibitory activity was due to a small molecular weight, heat-stable, non-proteinaceous component/s of serum. Serum-mediated inhibition of biofilm formation may represent a previously uncharacterized aspect of host innate immunity that targets the expression of a key bacterial virulence factor: the ability to establish a resistant biofilm. Metal ion chelators like sodium citrate are frequently chosen to lock intravenous catheters because they are regarded as potent inhibitors of bacterial biofilm formation and viability. We found that, while chelating compounds abolished biofilm formation in most strains of S. aureus, they actually augmented the phenotype in a subset of strains. We

Comparison of comprehensive two-dimensional gas chromatography coupled with sulfur-chemiluminescence detector to standard methods for speciation of sulfur-containing compounds in middle distillates.

Science.gov (United States)

Ruiz-Guerrero, Rosario; Vendeuvre, Colombe; Thiébaut, Didier; Bertoncini, Fabrice; Espinat, Didier

2006-10-01

The monitoring of total sulfur content and speciation of individual sulfur-containing compounds in middle distillates is required for efficient catalyst selection and for a better understanding of the kinetics of the reactions involved in hydrotreament processes. Owing to higher resolution power and enhanced sensitivity, comprehensive two-dimensional gas chromatography (GCxGC) hyphenated to sulfur chemiluminescence detection (SCD) has recently evolved as a powerful tool for improving characterization and identification of sulfur compounds. The aim of this paper is to compare quantitatively GCxGC-SCD and various other methods commonly employed in the petroleum industry, such as X-ray fluorescence, conventional GC-SCD, and high-resolution mass spectrometry, for total sulfur content determination and speciation analysis. Different samples of middle distillates have been analyzed to demonstrate the high potential and important advantages of GCxGC-SCD for innovative and quantitative analysis of sulfur-containing compounds. More accurate and detailed results for benzothiophenes and dibenzothiophenes are presented, showing that GCxGC-SCD should become, in the future, an essential tool for sulfur speciation analysis.

Nature of impurities in fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+) chelates.

Science.gov (United States)

Alvarez-Fernández, Ana; Cremonini, Mauro A; Sierra, Miguel A; Placucci, Giuseppe; Lucena, Juan J

2002-01-16

Iron chelates derived from ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA), ethylenediaminedi(o-hydroxy-p-methylphenylacetic) acid (EDDHMA), ethylenediaminedi(2-hydroxy-5-sulfophenylacetic) acid (EDDHSA), and ethylenediaminedi(5-carboxy-2-hydroxyphenylacetic) acid (EDDCHA) are remarkably efficient in correcting iron chlorosis in plants growing in alkaline soils. This work reports the determination of impurities in commercial samples of fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+). The active components (EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+)) were separated easily from other compounds present in the fertilizers by HPLC. Comparison of the retention times and the UV-visible spectra of the peaks obtained from commercial EDDHSA/Fe(3+) and EDDCHA/Fe(3+) samples with those of standard solutions showed that unreacted starting materials (p-hydroxybenzenesulfonic acid and p-hydroxybenzoic acid, respectively) were always present in the commercial products. 1D and 2D NMR experiments showed that commercial fertilizers based on EDDHMA/Fe(3+) contained impurities having structures tentatively assigned to iron chelates of two isomers of EDDHMA. These findings suggest that current production processes of iron chelates used in agriculture need to be improved.

Synthesis and Odor Evaluation of Five New Sulfur-Containing Ester Flavor Compounds from 4-Ethyloctanoic Acid

Directory of Open Access Journals (Sweden)

Baoguo Sun

2010-07-01

Full Text Available Five sulfur-containing flavor compounds were synthesized for the first time by the reaction of 4-ethyloctanoyl chloride with sulfur-containing alcohols or mercaptans. The synthesized compounds are 3-(methylthiopropyl 4-ethyloctanoate, 2-methyl-3-tetrahydro-furanthiol 4-ethyloctanoate, 4-methyl-5-thiazoleethanol 4-ethyloctanoate, 2-furan-methanethiol 4-ethyloctanoate and 2-methyl-3-furanthiol 4-ethyloctanoate. These five synthetic sulfur-containing ester flavor compounds all have meaty odor and might be used in foods if approved for this purpose in the future.

Synthesis and odor evaluation of five new sulfur-containing ester flavor compounds from 4-ethyloctanoic acid.

Science.gov (United States)

Liu, Yuping; Chen, Haitao; Yin, Decai; Sun, Baoguo

2010-07-29

Five sulfur-containing flavor compounds were synthesized for the first time by the reaction of 4-ethyloctanoyl chloride with sulfur-containing alcohols or mercaptans. The synthesized compounds are 3-(methylthio)propyl 4-ethyloctanoate, 2-methyl-3-tetrahydro-furanthiol 4-ethyloctanoate, 4-methyl-5-thiazoleethanol 4-ethyloctanoate, 2-furan-methanethiol 4-ethyloctanoate and 2-methyl-3-furanthiol 4-ethyloctanoate. These five synthetic sulfur-containing ester flavor compounds all have meaty odor and might be used in foods if approved for this purpose in the future.

Sulfur-containing components of gamma-irradiated garlic bulbs

Energy Technology Data Exchange (ETDEWEB)

Joongho Kwon (Korea Advanced Energy Research Inst., Daeduk (Republic of Korea)); Jonguck Choi; Hyungsik Yoon (Kyungpook National Univ., Taegu (Republic of Korea))

1989-01-01

Sulfur-containing components associated with garlic flavors were investigated to determine the effect of {gamma}-irradiation at 0.1Gy on the quality of garlic bulbs (Allium sativum L.) during storage at 3{plus minus}1{sup 0}C and 80{plus minus}5% RH for 10 months. Irradiation treatment had no influence on the amount of total sulfur and thiosulfinate of stored garlic for 10 months, while the storage period brought about a significant reduction (P < 0.05) in the content of both components after the 6-8th month of storage compared with that at the beginning of storage period. The identity of irradiated alliin (S-allyl-L-cysteine sulfoxide) at sprout-inhibition dose was confirmed according to thin-layer chromatography, i.r. and NMR spectroscopy data. (author).

Chemical and biological properties of toxic metals and use of chelating agents for the pharmacological treatment of metal poisoning

Energy Technology Data Exchange (ETDEWEB)

Sinicropi, Maria Stefania; Caruso, Anna [University of Calabria, Department of Pharmaceutical Sciences, Rende (Italy); Amantea, Diana [University of Calabria, Department of Pharmacobiology, Rende (Italy); Saturnino, Carmela [University of Salerno, Department of Pharmaceutical Sciences, Fisciano (Italy)

2010-07-15

Exposure to toxic metals is a well-known problem in industrialized countries. Metals interfere with a number of physiological processes, including central nervous system (CNS), haematopoietic, hepatic and renal functions. In the evaluation of the toxicity of a particular metal it is crucial to consider many parameters: chemical forms (elemental, organic or inorganic), binding capability, presence of specific proteins that selectively bind metals, etc. Medical treatment of acute and chronic metal toxicity is provided by chelating agents, namely organic compounds capable of interacting with metal ions to form structures called chelates. The present review attempts to provide updated information about the mechanisms, the cellular targets and the effects of toxic metals. (orig.)

Method for the treatment of mining gangue containing sulfuric acid

Energy Technology Data Exchange (ETDEWEB)

Minnick, L J; Smith, C L; Webster, W C

1976-07-01

Mining gangue is often heaped up on large, open-air dumps. By means of extraction and oxidation of the sulfuric elements contained, the environment is being negatively influenced, due to the sulfuric acids occuring. The method described converts the gangue into an ecologically agreeable material which can be used even in road construction. This is achieved by mixing the gangue with lime, a pozzolane active material and water, and by hardening the gangue at atmospheric pressure for several days. This method can be very cost-effective if fly ash is used as pozzolane-active material.

Mesoporous organosilica nanotubes containing a chelating ligand in their walls

Directory of Open Access Journals (Sweden)

Xiao Liu

2014-11-01

Full Text Available We report the synthesis of organosilica nanotubes containing 2,2′-bipyridine chelating ligands within their walls, employing a single-micelle-templating method. These nanotubes have an average pore diameter of 7.8 nm and lengths of several hundred nanometers. UV-vis absorption spectra and scanning transmission electron microscopy observations of immobilized nanotubes with an iridium complex on the bipyridine ligands showed that the 2,2′-bipyridine groups were homogeneously distributed in the benzene-silica walls. The iridium complex, thus, immobilized on the nanotubes exhibited efficient catalytic activity for water oxidation using Ce4+, due to the ready access of reactants to the active sites in the nanotubes.

Augmenting Sulfur Metabolism and Herbivore Defense in Arabidopsis by Bacterial Volatile Signaling

Directory of Open Access Journals (Sweden)

Mina eAziz

2016-04-01

Full Text Available Sulfur is an element necessary for the life cycle of higher plants. Its assimilation and reduction into essential biomolecules are pivotal factors determining a plant’s growth and vigor as well as resistance to environmental stress. While certain soil microbes can enhance ion solubility via chelating agents or oxidation, microbial regulation of plant-sulfur assimilation has not been reported. With an increasing understanding that soil microbes can activate growth and stress tolerance in plants via chemical signaling, the question arises as to whether such beneficial bacteria also regulate sulfur assimilation. Here we report a previously unidentified mechanism by which the growth-promoting rhizobacterium Bacillus amyloliquefaciens (GB03 transcriptionally activates genes responsible for sulfur assimilation, increasing sulfur uptake and accumulation in Arabidopsis. Transcripts encoding for sulfur-rich aliphatic and indolic glucosinolates are also GB03 induced. As a result, GB03-exposed plants with elevated glucosinolates exhibit greater protection against the generalist herbivore, Spodoptera exigua (beet armyworm. In contrast, a previously-characterized glucosinolate mutant compromised in the production of both aliphatic and indolic glucosinolates is also compromised in terms of GB03-induced protection against insect herbivory. As with in vitro studies, soil-grown plants show enhanced glucosinolate accumulation and protection against beet armyworm feeding with GB03 exposure. These results demonstrate the potential of microbes to enhance plant sulfur assimilation and emphasize the sophisticated integration of microbial signaling in plant defense.

Comments on chelation therapy

International Nuclear Information System (INIS)

Wrenn, M.E.

1981-01-01

The primary purpose of actinide chelation is to decrease the risk from radiation-induced cancer. While occupational exposures in the past have mainly involved low specific activity 239 Pu, future exposures will increasingly involve high specific activity plutonium, americium, and curium - all of which clear more rapidly from the lung. This will tend to shift the cancer risk from lung to bone and liver. Although therapy with Ca- or Zn-DTPA rapidly removes 241 Am from the canine, the sub-human primate, and the human liver, improved methods for removal from bone and lung are needed. DTPA can remove 241 Am more easily from the growing skeleton of a child than from the mature skeleton of an adult. Investigators at Karlsruhe are developing chelation agents for oral administration and are investigating the reduction in local dose to bone resulting from chelation therapy

14 CFR 23.1199 - Extinguishing agent containers.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Extinguishing agent containers. 23.1199... Powerplant Fire Protection § 23.1199 Extinguishing agent containers. For commuter category airplanes, the following applies: (a) Each extinguishing agent container must have a pressure relief to prevent bursting of...

Removal and recovery of nitrogen and sulfur oxides from gaseous mixtures containing them

International Nuclear Information System (INIS)

Cooper, H.B.H.

1984-01-01

A cyclic process for removing lower valence nitrogen oxides from gaseous mixtures includes treating the mixtures with an aqueous media including alkali metal carbonate and alkali metal bicarbonate and a preoxygen oxidant to form higher valence nitrogen oxides and to capture these oxides as alkali metal salts, expecially nitrites and nitrates, in a carbonate/bicarbonate-containing product aqueous media. Highly selective recovery of nitrates in high purity and yield may then follow, as by crystallization, with the carbonate and bicarbonate alkali metal salts strongly increasing the selectivity and yield of nitrates. The product nitrites are converted to nitrates by oxidation after lowering the product aqueous media pH to below about 9. A cyclic process for removing sulfur oxides from gas mixtures includes treating these mixtures includes treating these mixtures with aqueous media including alkali metal carbonate and alkali metal bicarbonate where the ratio of alkali metal to sulfur dioxide is not less than 2. The sulfur values may be recovered from the resulting carbonate/bicarbonate/-sulfite containing product aqueous media as alkali metal sulfate or sulfite salts which are removed by crystallization from the carbonate-containing product aqueous media. As with the nitrates, the carbonate/bicarbonate system strongly increases yield of sulfate or sulfite during crystallization. Where the gas mixtures include both sulfur dioxide and lower valence nitrogen oxides, the processes for removing lower valence nitrogen oxides and sulfur dioxide may be combined into a single removal/recovery system, or may be effected in sequence

Metal-oxo containing polymer nanobeads as potential contrast agents for magnetic resonance imaging

Science.gov (United States)

Pablico, Michele Huelar

Magnetic resonance imaging (MRI) has greatly revolutionized the way diseases are detected and treated, as it is a non-invasive imaging modality solely based on the interaction of radiowaves and hydrogen nuclei in the presence of an external magnetic field. It is widely used today for the diagnosis of diseases as it offers an efficient method of mapping structure and function of soft tissues in the body. Most MRI examinations utilize paramagnetic materials known as contrast agents, which enhance the MR signal by decreasing the longitudinal (T1) and transverse (T2) relaxation times of the surrounding water protons in biological systems. This results into increased signal intensity differences thereby allowing better interpretation and analysis of pathological tissues. Contrast agents function by lowering the T1 or lowering the T2, resulting into bright and dark contrasts, respectively. The most common MRI contrast agents that are in clinical use today are gadolinium chelates and superparamagnetic iron oxide nanoparticles, both of which have their own advantages in terms of contrast enhancement properties. In the past few years, however, there has been interest in utilizing metal-containing clusters for MRI contrast enhancement as these materials bridge the gap between the constrained structure and magnetic properties of the gadolinium chelates with the superparamagnetic behavior of the iron oxide nanoparticles. Recently, metallic clusters containing Mn and Fe metal centers have received increased attention mainly because of their potential for high spin states and benign nature. In the quest to further develop novel imaging agents, this research has focused on investigating the use of metal-oxo clusters as potential contrast agents for MRI. The primary goal of this project is to identify clusters that meet the following criteria: high paramagnetic susceptibility, water-soluble, stable, cheap, contain environmentally benign metals, and easily derivatized. This work is

Degradation of the blister agent sulfur mustard, bis(2-chloroethyl) sulfide, on concrete

International Nuclear Information System (INIS)

Brevett, Carol A.S.; Sumpter, Kenneth B.; Wagner, George W.; Rice, Jeffrey S.

2007-01-01

The products formed from the degradation of the blister agent sulfur mustard [bis(2-chloroethyl) sulfide] on concrete were identified using gas chromatography with mass spectrometry detection (GC/MSD), 1 H NMR, 2D 1 H- 13 C NMR and 13 C solid state magic angle spinning (SSMAS) NMR. In situ and extraction experiments were performed. Sulfur mustard was detected in the in situ 13 C SSMAS samples for 12 weeks, whereas less than 5% of the sulfur mustard was detected in extracts from the concrete monoliths after 8 days. Sulfonium ions and (2-chloroethylthio)ethyl ether (T) were observed on the in situ samples after a period of 12 weeks, whereas vinyl species and bis(2-chloroethyl) sulfoxide were observed in the extracts of the concrete monoliths within 24 h. The differences between the extraction and the SSMAS data indicated that the sulfur mustard existed in the concrete in a non-extractable form prior to its degradation. Extraction methods alone were not sufficient to identify the products; methods to identify the presence of non-extractable degradation products were also required

Chelation in root canal therapy reconsidered.

Science.gov (United States)

Zehnder, Matthias; Schmidlin, Patrick; Sener, Beatrice; Waltimo, Tuomas

2005-11-01

The aim of this study was to assess interactions of EDTA and citric acid (CA) with sodium hypochlorite (NaOCl), the indispensable endodontic irrigant. Other chelators were simultaneously evaluated as possible alternatives: sodium triphosphate (STP), amino tris methylenephosphonic acid (ATMA), and 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP). Available chlorine was titrated in chelator-NaOCl solutions. All chelators other than HEBP and STP caused an almost complete, immediate loss of available chlorine in solution. Atomic absorbtion spectrometry and SEM evaluation of root canal walls of instrumented teeth indicated that NaOCl had no negative effect on calcium-complexing ability of chelators. STP was too weak a complexing agent to warrant further studies. Finally, CA-, EDTA-, and HEBP-NaOCl mixtures were evaluated for their antimicrobial capacity. Again, EDTA and CA negatively interfered with NaOCl, while HEBP did not.

Chelating agents related to ethylenediamine bis(2-hydroxyphenyl)acetic acid (EDDHA): synthesis, characterization, and equilibrium studies of the free ligands and their Mg2+, Ca2+, Cu2+, and Fe3+ chelates.

Science.gov (United States)

Yunta, Felipe; García-Marco, Sonia; Lucena, Juan J; Gómez-Gallego, Mar; Alcázar, Roberto; Sierra, Miguel A

2003-08-25

Iron chelates such as ethylenediamine-N,N'-bis(2-hydroxyphenyl)acetic acid (EDDHA) and their analogues are the most efficient soil fertilizers to treat iron chlorosis in plants growing in calcareous soils. EDDHA, EDDH4MA (ethylenediamine-N,N'-bis(2-hydroxy-4-methylphenyl)acetic acid), and EDDCHA (ethylenediamine-N,N'-bis(2-hydroxy-5-carboxyphenyl)acetic acid) are allowed by the European directive, but also EDDHSA (ethylenediamine-N,N'-bis(2-hydroxy-5-sulfonylphenyl)acetic acid) and EDDH5MA (ethylenediamine-N,N'-bis(2-hydroxy-5-methylphenyl)acetic acid) are present in several commercial iron chelates. In this study, these chelating agents as well as p,p-EDDHA (ethylenediamine-N,N'-bis(4-hydroxyphenyl)acetic acid) and EDDMtxA (ethylenediamine-N,N'-bis(2-metoxyphenyl)acetic acid) have been obtained following a new synthetic pathway. Their chemical behavior has been studied to predict the effect of the substituents in the benzene ring on their efficacy as iron fertilizers for soils above pH 7. The purity of the chelating agents has been determined using a novel methodology through spectrophotometric titration at 480 nm with Fe(3+) as titrant to evaluate the inorganic impurities. The protonation constants were determined by both spectrophotometric and potentiometric methods, and Ca(2+) and Mg(2+) stability constants were determined from potentiometric titrations. To establish the Fe(3+) and Cu(2+) stability constants, a new spectrophotometric method has been developed, and the results were compared with those reported in the literature for EDDHA and EDDHMA and their meso- and rac-isomers. pM values have been also determined to provide a comparable basis to establish the relative chelating ability of these ligands. The purity obtained for the ligands is higher than 87% in all cases and is comparable with that obtained by (1)H NMR. No significant differences have been found among ligands when their protonation and stability constants were compared. As expected, no Fe(3

An experimental study on lead removing effect of new chelating agent-FZ-820-4

International Nuclear Information System (INIS)

Feng Jue; Zhang Kangrong; Yin Xieyu; Ji Shaowei

2001-01-01

To evaluate the lead removing effects of F Z-82-4, a new chelating agent, and to compare it with those of DTPA, EDTA, H-73-10 and control group. The experiments are carried out using rats. The Pb-nitrate removing effect of FZ-82-4 was obviously superior to those EDTA, H-73-10 and control group, and equivalent to that of DTPA. According to lead excreting rate of urine in 24 hours. For lead retention rate in bones, liver and kidneys, F Z-82-4 group was lower than control group. The Pb-nitrate removing effect of FZ-82-4 was related to administering time, route and dose

A Universal Strategy To Prepare Sulfur-Containing Polymer Composites with Desired Morphologies for Lithium-Sulfur Batteries.

Science.gov (United States)

Zeng, Shao-Zhong; Zeng, Xierong; Tu, Wenxuan; Huang, Haitao; Yu, Liang; Yao, Yuechao; Jin, Nengzhi; Zhang, Qi; Zou, Jizhao

2018-06-19

Lithium-sulfur (Li-S) batteries are probably the most promising candidates for the next-generation batteries owing to their high energy density. However, Li-S batteries face severe technical problems where the dissolution of intermediate polysulfides is the biggest problem because it leads to the degradation of the cathode and the lithium anode, and finally the fast capacity decay. Compared with the composites of elemental sulfur and other matrices, sulfur-containing polymers (SCPs) have strong chemical bonds to sulfur and therefore show low dissolution of polysulfides. Unfortunately, most SCPs have very low electron conductivity and their morphologies can hardly be controlled, which undoubtedly depress the battery performances of SCPs. To overcome these two weaknesses of SCPs, a new strategy was developed for preparing SCP composites with enhanced conductivity and desired morphologies. With this strategy, macroporous SCP composites were successfully prepared from hierarchical porous carbon. The composites displayed discharge/charge capacities up to 1218/1139, 949/922, and 796/785 mA h g -1 at the current rates of 5, 10, and 15 C, respectively. Considering the universality of this strategy and the numerous morphologies of carbon materials, this strategy opens many opportunities for making carbon/SCP composites with novel morphologies.

Biodegradable gadolinium-chelated cationic poly(urethane amide) copolymers for gene transfection and magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Gao, Xiaolong [Department of Radiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065 (China); Wang, Gangmin [Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040 (China); Shi, Ting [The Institute for Translational Nanomedicine, Shanghai East Hospital, Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Shanghai 200092 (China); Shao, Zhihong [Department of Radiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065 (China); Zhao, Peng; Shi, Donglu [The Institute for Translational Nanomedicine, Shanghai East Hospital, Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Shanghai 200092 (China); Ren, Jie [Institute of Nano and Biopolymeric Materials, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804 (China); Lin, Chao, E-mail: chaolin@tongji.edu.cn [The Institute for Translational Nanomedicine, Shanghai East Hospital, Institute for Biomedical Engineering and Nanoscience, Tongji University School of Medicine, Shanghai 200092 (China); Wang, Peijun, E-mail: tjpjwang@sina.com [Department of Radiology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065 (China)

2016-08-01

Theranostic nano-polyplexes containing gene and imaging agents hold a great promise for tumor diagnosis and therapy. In this work, we develop a group of new gadolinium (Gd)-chelated cationic poly(urethane amide)s for gene delivery and T{sub 1}-weighted magnetic resonance (MR) imaging. Cationic poly(urethane amide)s (denoted as CPUAs) having multiple disulfide bonds, urethane and amide linkages were synthesized by stepwise polycondensation reaction between 1,4-bis(3-aminopropyl)piperazine and a mixture of di(4-nitrophenyl)-2, 2′-dithiodiethanocarbonate (DTDE-PNC) and diethylenetriaminepentaacetic acid (DTPA) dianhydride at varied molar ratios. Then, Gd-chelated CPUAs (denoted as GdCPUAs) were produced by chelating Gd(III) ions with DTPA residues of CPUAs. These GdCPUAs could condense gene into nanosized and positively-charged polyplexes in a physiological condition and, however, liberated gene in an intracellular reductive environment. In vitro transfection experiments revealed that the GdCPUA at a DTDE-PNC/DTPA residue molar ratio of 85/15 induced the highest transfection efficiency in different cancer cells. This efficiency was higher than that yielded with 25 kDa branched polyethylenimine as a positive control. GdCPUAs and their polyplexes exhibited low cytotoxicity when an optimal transfection activity was detected. Moreover, GdCPUAs may serve as contrast agents for T{sub 1}-weighted magnetic resonance imaging. The results of this work indicate that biodegradable Gd-chelated cationic poly(urethane amide) copolymers have high potential for tumor theranostics. - Highlights: • Novel cationic gadolinium-chelated poly(urethane amide)s (GdCPUAs) are prepared. • GdCPUAs can induce a high transfection efficacy in different cancer cells. • GdCPUAs reveal good cyto-compatibility against cancer cells. • GdCPUAs may be applied as T{sub 1}-contrast agents for magnetic resonance imaging. • GdCPUAs hold high potential for cancer theranostics.

Biodegradable gadolinium-chelated cationic poly(urethane amide) copolymers for gene transfection and magnetic resonance imaging

International Nuclear Information System (INIS)

Gao, Xiaolong; Wang, Gangmin; Shi, Ting; Shao, Zhihong; Zhao, Peng; Shi, Donglu; Ren, Jie; Lin, Chao; Wang, Peijun

2016-01-01

Theranostic nano-polyplexes containing gene and imaging agents hold a great promise for tumor diagnosis and therapy. In this work, we develop a group of new gadolinium (Gd)-chelated cationic poly(urethane amide)s for gene delivery and T 1 -weighted magnetic resonance (MR) imaging. Cationic poly(urethane amide)s (denoted as CPUAs) having multiple disulfide bonds, urethane and amide linkages were synthesized by stepwise polycondensation reaction between 1,4-bis(3-aminopropyl)piperazine and a mixture of di(4-nitrophenyl)-2, 2′-dithiodiethanocarbonate (DTDE-PNC) and diethylenetriaminepentaacetic acid (DTPA) dianhydride at varied molar ratios. Then, Gd-chelated CPUAs (denoted as GdCPUAs) were produced by chelating Gd(III) ions with DTPA residues of CPUAs. These GdCPUAs could condense gene into nanosized and positively-charged polyplexes in a physiological condition and, however, liberated gene in an intracellular reductive environment. In vitro transfection experiments revealed that the GdCPUA at a DTDE-PNC/DTPA residue molar ratio of 85/15 induced the highest transfection efficiency in different cancer cells. This efficiency was higher than that yielded with 25 kDa branched polyethylenimine as a positive control. GdCPUAs and their polyplexes exhibited low cytotoxicity when an optimal transfection activity was detected. Moreover, GdCPUAs may serve as contrast agents for T 1 -weighted magnetic resonance imaging. The results of this work indicate that biodegradable Gd-chelated cationic poly(urethane amide) copolymers have high potential for tumor theranostics. - Highlights: • Novel cationic gadolinium-chelated poly(urethane amide)s (GdCPUAs) are prepared. • GdCPUAs can induce a high transfection efficacy in different cancer cells. • GdCPUAs reveal good cyto-compatibility against cancer cells. • GdCPUAs may be applied as T 1 -contrast agents for magnetic resonance imaging. • GdCPUAs hold high potential for cancer theranostics.

Biomolecule conjugation strategy using novel water-soluble phosphine-based chelating agents

Science.gov (United States)

Katti, Kattesh V.; Gali, Hariprasad; Volkert, Wynn A.

2004-08-24

This invention describes a novel strategy to produce phosphine-functionalized biomolecules (e.g. peptides or proteins) for potential use in the design and development of site-specific radiopharmaceuticals for diagnosis or therapy of specific cancers. Hydrophilic alkyl phosphines, in general, tend to be oxidatively unstable. Therefore, incorporation of such phosphine functionalities on peptide (and other biomolecule) backbones, without oxidizing the P.sup.III centers, is difficult. In this context this discovery reports on a new technology by which phosphines, in the form of bifunctional chelating agents, can be directly incorporated on biomolecular backbones using manual synthetic or solid phase peptide synthesis methodologies. The superior ligating abilities of phosphine ligands, with various diagnostically (e.g. TC-99m) or therapeutically (e.g. Re186/188, Rh-105, Au-199) useful radiometals, coupled with the findings that the resulting complexes demonstrate high in vivo stability makes this approach useful in the development of radiolabeled biomolecules for applications in the design of tumor-specific radiopharmaceuticals.

Durability of solid oxide fuel cells using sulfur containing fuels

DEFF Research Database (Denmark)

Hagen, Anke; Rasmussen, Jens Foldager Bregnballe; Thydén, Karl Tor Sune

2011-01-01

The usability of hydrogen and also carbon containing fuels is one of the important advantages of solid oxide fuel cells (SOFCs), which opens the possibility to use fuels derived from conventional sources such as natural gas and from renewable sources such as biogas. Impurities like sulfur compounds...... are critical in this respect. State-of-the-art Ni/YSZ SOFC anodes suffer from being rather sensitive towards sulfur impurities. In the current study, anode supported SOFCs with Ni/YSZ or Ni/ScYSZ anodes were exposed to H2S in the ppm range both for short periods of 24h and for a few hundred hours. In a fuel...

Separation and recovery of uranium ore by chlorinating, chelate resin and molten salt treatment

International Nuclear Information System (INIS)

Taki, Tomohiro

2000-12-01

Three fundamental researches of separation and recovery of uranium from uranium ore are reported in this paper. Three methods used the chloride pyrometallurgy, sodium containing molten salts and chelate resin. When uranium ore is mixed with activated carbon and reacted for one hour under the mixed gas of chlorine and oxygen at 950 C, more than 90% uranium volatilized and vaporization of aluminum, silicone and phosphorus were controlled. The best activated carbon was brown coal because it was able to control the large range of oxygen concentration. By blowing oxygen into the molten sodium hydroxide, the elution rate of uranium attained to about 95% and a few percent of uranium was remained in the residue. On the uranium ore of unconformity-related uranium deposits, a separation method of uranium, molybdenum, nickel and phosphorus from the sulfuric acid elusion solution with U, Ni, As, Mo, Fe and Al was developed. Methylene phosphonic acid type chelate resin (RCSP) adsorbed Mo and U, and then 100 % Mo was eluted by sodium acetate solution and about 100% U by sodium carbonate solution. Ni and As in the passing solution were recovered by imino-diacetic acid type chelate resin and iron hydroxide, respectively. (S.Y.)

Process and system for removing sulfur from sulfur-containing gaseous streams

Science.gov (United States)

Basu, Arunabha; Meyer, Howard S.; Lynn, Scott; Leppin, Dennis; Wangerow, James R.

2012-08-14

A multi-stage UCSRP process and system for removal of sulfur from a gaseous stream in which the gaseous stream, which contains a first amount of H.sub.2S, is provided to a first stage UCSRP reactor vessel operating in an excess SO.sub.2 mode at a first amount of SO.sub.2, producing an effluent gas having a reduced amount of SO.sub.2, and in which the effluent gas is provided to a second stage UCSRP reactor vessel operating in an excess H.sub.2S mode, producing a product gas having an amount of H.sub.2S less than said first amount of H.sub.2S.

Assessment of toxicity on chelating agent DTPA (diethylenetriaminepentaacetic acid)

International Nuclear Information System (INIS)

Fukuda, Satoshi

1989-01-01

DTPA (diethylenetriaminepentaacetic acid) is a very important chelating agent to decorporate the radionuclides such as plutonium and americium from human body. However, before DTPA will be administered to humans, the toxicity should be clarified. This report described the summary on data of DTPA toxicities obtained from animal experiments and assessment on the safety for humans, based on the results that compared their data among animal species. In short, Ca-DTPA is less toxic than Zn-DTPA when it is injected intravenously, while Zn-DTPA is less toxic than Ca-DTPA when it is administered orally. Both DTPAs acted on the serum calcium metabolism and induced the functional damages of cardiovascular system. Particularly, it is stressed that Zn-DTPA by intravenous injection occurred the heart failure, increases of blood pressure and pulse with hypocalcemia in even normal rats and beagle dogs. Other side effects by both DTPAs were also observed in the intestine, liver, kidney and bone. It is estimated that there are almost no species differences on DTPA toxicity between animals and humans. As a result, it is concluded that DTPA should be used very carefully for humans, with reference to the results obtained from animal experiments. (author) 61 refs

Assessment of toxicity on chelating agent DTPA (diethylenetriaminepentaacetic acid)

Energy Technology Data Exchange (ETDEWEB)

Fukuda, Satoshi (National Inst. of Radiological Sciences, Chiba (Japan))

1989-09-01

DTPA (diethylenetriaminepentaacetic acid) is a very important chelating agent to decorporate the radionuclides such as plutonium and americium from human body. However, before DTPA will be administered to humans, the toxicity should be clarified. This report described the summary on data of DTPA toxicities obtained from animal experiments and assessment on the safety for humans, based on the results that compared their data among animal species. In short, Ca-DTPA is less toxic than Zn-DTPA when it is injected intravenously, while Zn-DTPA is less toxic than Ca-DTPA when it is administered orally. Both DTPAs acted on the serum calcium metabolism and induced the functional damages of cardiovascular system. Particularly, it is stressed that Zn-DTPA by intravenous injection occurred the heart failure, increases of blood pressure and pulse with hypocalcemia in even normal rats and beagle dogs. Other side effects by both DTPAs were also observed in the intestine, liver, kidney and bone. It is estimated that there are almost no species differences on DTPA toxicity between animals and humans. As a result, it is concluded that DTPA should be used very carefully for humans, with reference to the results obtained from animal experiments. (author) 61 refs.

Quantitative Determination of NTA and Other Chelating Agents in Detergents by Potentiometric Titration with Copper Ion Selective Electrode.

Science.gov (United States)

Ito, Sana; Morita, Masaki

2016-01-01

Quantitative analysis of nitrilotriacetate (NTA) in detergents by titration with Cu 2+ solution using a copper ion selective electrode was achieved. This method tolerates a wide range of pH and ingredients in detergents. In addition to NTA, other chelating agents, having relatively lower stability constants toward Cu 2+ , were also qualified with sufficient accuracy by this analytical method for model detergent formulations. The titration process was automated by automatic titrating systems available commercially.

Decomposition rates of radiopharmaceutical indium chelates in serum

International Nuclear Information System (INIS)

Yeh, S.M.; Meares, C.F.; Goodwin, D.A.

1979-01-01

The rates at which six small aminopolycarboxylate chelates of trivalent 111 In and three protein-bound chelates of 111 In deliver indium to the serum protein transferrin have been studied in sterile human serum at pH 7.3, 37 deg C. Sterically hindered chelates containing a substituent on an ethylene carbon of EDTA decompose with rates in the range 0.03 to 0.11% per day - one to two orders of magnitude slower than other chelates. Only small differences are observed between rates of decomposition for low-molecular-weight chelates and for protein-bound chelates having analogous structures. (author)

Low-Molecular-Weight Iron Chelates May Be an Alternative to Gadolinium-based Contrast Agents for T1-weighted Contrast-enhanced MR Imaging.

Science.gov (United States)

Boehm-Sturm, Philipp; Haeckel, Akvile; Hauptmann, Ralf; Mueller, Susanne; Kuhl, Christiane K; Schellenberger, Eyk A

2018-02-01

Purpose To synthesize two low-molecular-weight iron chelates and compare their T1 contrast effects with those of a commercial gadolinium-based contrast agent for their applicability in dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging. Materials and Methods The animal experiments were approved by the local ethics committee. Two previously described iron (Fe) chelates of pentetic acid (Fe-DTPA) and of trans-cyclohexane diamine tetraacetic acid (Fe-tCDTA) were synthesized with stability constants several orders of magnitude higher than those of gadolinium-based contrast agents. The T1 contrast effects of the two chelates were compared with those of gadopentetate dimeglumine in blood serum phantoms at 1.5 T, 3 T, and 7 T. For in vivo studies, a human breast cancer cell line (MDA-231) was implanted in five mice per group. The dynamic contrast effects of the chelates were compared by performing DCE MR imaging with intravenous application of Fe-DTPA or Fe-tCDTA on day 1 and DCE MR imaging in the same tumors with gadopentetate dimeglumine on day 2. Quantitative DCE maps were generated with software and were compared by means of a one-tailed Pearson correlation test. Results Relaxivities in serum (0.94 T at room temperature) of Fe-tCDTA (r1 = 2.2 mmol -1 · sec -1 , r2 = 2.5 mmol -1 · sec -1 ) and Fe-DTPA (r1 = 0.9 mmol -1 · sec -1 , r2 = 0.9 mmol -1 · sec -1 ) were approximately twofold and fivefold lower, respectively, compared with those of gadopentetate dimeglumine (r1 = 4.1 mmol -1 · sec -1 , r2 = 4.8 mmol -1 · sec -1 ). Used at moderately higher concentrations, however, iron chelates generated similar contrast effects at T1-weighted MR imaging in vitro in serum, in vivo in blood, and for DCE MR imaging of breast cancer xenografts. The volume transfer constant values for Fe-DTPA and Fe-tCDTA in the same tumors correlated well with those observed for gadopentetate dimeglumine (Fe-tCDTA Pearson R, 0.99; P = .0003; Fe-DTPA Pearson R, 0.97; P

Synergy and antagonism between iron chelators and antifungal drugs in Cryptococcus.

Science.gov (United States)

Lai, Yu-Wen; Campbell, Leona T; Wilkins, Marc R; Pang, Chi Nam Ignatius; Chen, Sharon; Carter, Dee A

2016-10-01

Fungal infections remain very difficult to treat, and developing new antifungal drugs is difficult and expensive. Recent approaches therefore seek to augment existing antifungals with synergistic agents that can lower the therapeutic dose, increase efficacy and prevent resistance from developing. Iron limitation can inhibit microbial growth, and iron chelators have been employed to treat fungal infections. In this study, chequerboard testing was used to explore combinations of iron chelators with antifungal agents against pathogenic Cryptococcus spp. with the aim of determining how disruption to iron homeostasis affects antifungal susceptibility. The iron chelators ethylenediaminetetraacetic acid (EDTA), deferoxamine (DFO), deferiprone (DFP), deferasirox (DSX), ciclopirox olamine and lactoferrin (LF) were paired with the antifungal agents amphotericin B (AmB), fluconazole, itraconazole, voriconazole and caspofungin. All chelators except for DFO increased the efficacy of AmB, and significant synergy was seen between AmB and LF for all Cryptococcus strains. Addition of exogenous iron rescued cells from the antifungal effect of LF alone but could not prevent inhibition by AmB + LF, indicating that synergy was not due primarily to iron chelation but to other properties of LF that were potentiated in the presence of AmB. Significant synergy was not seen consistently for other antifungal-chelator combinations, and EDTA, DSX and DFP antagonised the activity of azole drugs in strains of Cryptococcus neoformans var. grubii. This study highlights the range of interactions that can be induced by chelators and indicates that most antifungal drugs are not enhanced by iron limitation in Cryptococcus. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Identification of novel sulfur-containing steroids in sediments and petroleum: probable incorporation of sulfur into δ 5,7-sterols during early diagenesis

Science.gov (United States)

Sinninghe Damsté, Jaap S.; Schouten, Stefan; de Leeuw, Jan W.; van Duin, Adri C. T.; Geenevasen, Jan A. J.

1999-01-01

A novel sulfur-containing sterane, 4α,7α-epithio-5β-cholestane, has been identified in a sediment extract from the Miocene Northern Apennines marl (Italy) after its isolation by column chromatography and high pressure liquid chromatography. The compound has been characterised by GC-MS and mild Nickel boride desulfurisation and one and two-dimensional 1H NMR techniques. C 27-C 29 homologs have been detected in sediment extracts of three different formations and in one petroleum sample. These sulfur-containing steroids are probably formed by an intramolecular reaction of inorganic sulfides with early diagenetic products of Δ 5,7-sterols.

Inhibition of Enzymatic Browning of Chlorogenic Acid by Sulfur-Containing Compounds

NARCIS (Netherlands)

Kuijpers, T.F.M.; Narvaez Cuenca, C.E.; Vincken, J.P.; Verloop, J.W.; Berkel, van W.J.H.; Gruppen, H.

2012-01-01

The antibrowning activity of sodium hydrogen sulfite (NaHSO3) was compared to that of other sulfur-containing compounds. Inhibition of enzymatic browning was investigated using a model browning system consisting of mushroom tyrosinase and chlorogenic acid (5-CQA). Development of brown color

Synthesis of l-cysteine derivatives containing stable sulfur isotopes and application of this synthesis to reactive sulfur metabolome.

Science.gov (United States)

Ono, Katsuhiko; Jung, Minkyung; Zhang, Tianli; Tsutsuki, Hiroyasu; Sezaki, Hiroshi; Ihara, Hideshi; Wei, Fan-Yan; Tomizawa, Kazuhito; Akaike, Takaaki; Sawa, Tomohiro

2017-05-01

Cysteine persulfide is an L-cysteine derivative having one additional sulfur atom bound to a cysteinyl thiol group, and it serves as a reactive sulfur species that regulates redox homeostasis in cells. Here, we describe a rapid and efficient method of synthesis of L-cysteine derivatives containing isotopic sulfur atoms and application of this method to a reactive sulfur metabolome. We used bacterial cysteine syntheses to incorporate isotopic sulfur atoms into the sulfhydryl moiety of L-cysteine. We cloned three cysteine synthases-CysE, CysK, and CysM-from the Gram-negative bacterium Salmonella enterica serovar Typhimurium LT2, and we generated their recombinant enzymes. We synthesized 34 S-labeled L-cysteine from O-acetyl-L-serine and 34 S-labeled sodium sulfide as substrates for the CysK or CysM reactions. Isotopic labeling of L-cysteine at both sulfur ( 34 S) and nitrogen ( 15 N) atoms was also achieved by performing enzyme reactions with 15 N-labeled L-serine, acetyl-CoA, and 34 S-labeled sodium sulfide in the presence of CysE and CysK. The present enzyme systems can be applied to syntheses of a series of L-cysteine derivatives including L-cystine, L-cystine persulfide, S-sulfo-L-cysteine, L-cysteine sulfonate, and L-selenocystine. We also prepared 34 S-labeled N-acetyl-L-cysteine (NAC) by incubating 34 S-labeled L-cysteine with acetyl coenzyme A in test tubes. Tandem mass spectrometric identification of low-molecular-weight thiols after monobromobimane derivatization revealed the endogenous occurrence of NAC in the cultured mammalian cells such as HeLa cells and J774.1 cells. Furthermore, we successfully demonstrated, by using 34 S-labeled NAC, metabolic conversion of NAC to glutathione and its persulfide, via intermediate formation of L-cysteine, in the cells. The approach using isotopic sulfur labeling combined with mass spectrometry may thus contribute to greater understanding of reactive sulfur metabolome and redox biology. Copyright © 2017 Elsevier Inc

Effect of Chelating Agents on the Stability of Nano-TiO2 Sol Particles for Sol-Gel Coating.

Science.gov (United States)

Maeng, Wan Young; Yoo, Mi

2015-11-01

Agglomeration of sol particles in a titanium alkoxide (tetrabutyl orthotitanate (TBOT), > 97%) solution during the hydrolysis and condensation steps makes the sol solution difficult to use for synthesizing homogeneous sol-gel coating. Here, we have investigated the effect of stabilizing agents (acetic acid and ethyl acetoacetate (EAcAc)) on the agglomeration of Ti alkoxide particles during hydrolysis and condensation in order to determine the optimized conditions for controlling the precipitation of TiO2 particles. The study was conducted at R(AC) ([acetic acid]/[TBOT]) = 0.1-5 and R(EAcAc)([EAcAc]/[TBOT]) = 0.05-0.65. We also studied the effects of a basic catalyst ethanolamine (ETA), water, and HCl on sol stability. The chelating ligands in the precursor sol were analyzed with FT-IR. The coating properties were examined by focused ion beam. The stabilizing agents (acetic acid and EAcAc) significantly influenced the agglomeration and precipitation of TBOT precursor particles during hydrolysis. As R(AC) and R(EAcAc) increased, the agglomeration remarkably decreased. The stability of the sol with acetic acid and EAcAc arises from the coordination of the chelating ligand to TBOT that hinders hydrolysis and condensation. A uniform fine coating (thickness: 30 nm) on stainless steel was obtained by using an optimized sol with R(AC) = 0.5 and R(EAcAc) = 0.65.

Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review

Directory of Open Access Journals (Sweden)

Margaret E. Sears

2013-01-01

Full Text Available Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavy metals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease.

Actual clinical use of gadolinium-chelates for non-MRI applications

Energy Technology Data Exchange (ETDEWEB)

Strunk, Holger M; Schild, H [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, 53105, Bonn (Germany)

2004-06-01

For many years, alternatives to iodinated X-ray contrast media have been sought. Of the contrast media investigated to date, only CO{sub 2} and the gadolinium-chelates have been shown to be viable alternatives for selected X-ray examinations. Therefore, we have reviewed the general literature and that specific for gadopentetate (Magnevist) in particular, since this agent has been studied the most. This review indicates that diagnostic CT examinations can be achieved following the intravenous administration of gadolinium-containing contrast media (CM) for evaluation of aortic abnormalities. Gadolinium-containing CM at the dose approved for MR imaging are not useful for CT evaluation of the abdominal parenchymal organs. Intravenous/intraarterial injections have also been used in a variety of angiographic and interventional procedures. Image quality, however, is generally inferior to iodinated contrast media. Gadolinium-containing CM require no special handling and can be administered by hand injection or via conventional angiographic automated injectors with the same flow rates and pressures as are used with iodinated contrast media. For CT, a peripheral bolus injection of a diluted gadolinium agent (1:1 with saline) of 60-90 ml at 3-5 ml/s is usually performed. Similar to all other gadolinium-chelates, the non-MRI use of gadopentetate (Magnevist) is not approved by regulatory agencies. However, the literature suggests that a dose of 0.3-0.4 mmol/kg b.w. has been safely administered for CT as well as for angiography and interventional procedures intravenously and intraarterially. Even at this dose, though, this results in a relatively small overall volume to be injected, which limits utility somewhat. (orig.)

Actual clinical use of gadolinium-chelates for non-MRI applications

International Nuclear Information System (INIS)

Strunk, Holger M.; Schild, H.

2004-01-01

For many years, alternatives to iodinated X-ray contrast media have been sought. Of the contrast media investigated to date, only CO 2 and the gadolinium-chelates have been shown to be viable alternatives for selected X-ray examinations. Therefore, we have reviewed the general literature and that specific for gadopentetate (Magnevist) in particular, since this agent has been studied the most. This review indicates that diagnostic CT examinations can be achieved following the intravenous administration of gadolinium-containing contrast media (CM) for evaluation of aortic abnormalities. Gadolinium-containing CM at the dose approved for MR imaging are not useful for CT evaluation of the abdominal parenchymal organs. Intravenous/intraarterial injections have also been used in a variety of angiographic and interventional procedures. Image quality, however, is generally inferior to iodinated contrast media. Gadolinium-containing CM require no special handling and can be administered by hand injection or via conventional angiographic automated injectors with the same flow rates and pressures as are used with iodinated contrast media. For CT, a peripheral bolus injection of a diluted gadolinium agent (1:1 with saline) of 60-90 ml at 3-5 ml/s is usually performed. Similar to all other gadolinium-chelates, the non-MRI use of gadopentetate (Magnevist) is not approved by regulatory agencies. However, the literature suggests that a dose of 0.3-0.4 mmol/kg b.w. has been safely administered for CT as well as for angiography and interventional procedures intravenously and intraarterially. Even at this dose, though, this results in a relatively small overall volume to be injected, which limits utility somewhat. (orig.)

Deaths associated with hypocalcemia from chelation therapy--Texas, Pennsylvania, and Oregon, 2003-2005.

Science.gov (United States)

2006-03-03

Chelating agents bind lead in soft tissues and are used in the treatment of lead poisoning to enhance urinary and biliary excretion of lead, thus decreasing total lead levels in the body. During the past 30 years, environmental and dietary exposures to lead have decreased substantially, resulting in a considerable decrease in population blood lead levels (BLLs) and a corresponding decrease in the number of patients requiring chelation therapy. Chelating agents also increase excretion of other heavy metals and minerals, such as zinc and, in certain cases, calcium. This report describes three deaths associated with chelation-therapy--related hypocalcemia that resulted in cardiac arrest. Several drugs are used in the treatment of lead poisoning, including edetate disodium calcium (CaEDTA), dimercaperol (British anti-Lewisite), D-penicillamine, and meso-2,3-dimercaptosuccinic acid (succimer). Health-care providers who are unfamiliar with chelating agents and are considering this treatment for lead poisoning should consult an expert in the chemotherapy of lead poisoning. Hospital pharmacies should evaluate whether continued stocking of Na2EDTA is necessary, given the established risk for hypocalcemia, the availability of less toxic alternatives, and an ongoing safety review by the Food and Drug Administration (FDA). Health-care providers and pharmacists should ensure that Na2EDTA is not administered to children during chelation therapy.

A batch assay to measure microbial hydrogen sulfide production from sulfur-containing solid wastes

International Nuclear Information System (INIS)

Sun, Mei; Sun, Wenjie; Barlaz, Morton A.

2016-01-01

Large volumes of sulfur-containing wastes enter municipal solid waste landfills each year. Under the anaerobic conditions that prevail in landfills, oxidized forms of sulfur, primarily sulfate, are converted to sulfide. Hydrogen sulfide (H 2 S) is corrosive to landfill gas collection and treatment systems, and its presence in landfill gas often necessitates the installation of expensive removal systems. For landfill operators to understand the cost of managing sulfur-containing wastes, an estimate of the H 2 S production potential is needed. The objective of this study was to develop and demonstrate a biochemical sulfide potential (BSP) test to measure the amount of H 2 S produced by different types of sulfur-containing wastes in a relatively fast (30 days) and inexpensive (125 mL serum bottles) batch assay. This study confirmed the toxic effect of H 2 S on both sulfate reduction and methane production in batch systems, and demonstrated that removing accumulated H 2 S by base adsorption was effective for mitigating inhibition. H 2 S production potentials of coal combustion fly ash, flue gas desulfurization residual, municipal solid waste combustion ash, and construction and demolition waste were determined in BSP assays. After 30 days of incubation, most of the sulfate in the wastes was converted to gaseous or aqueous phase sulfide, with BSPs ranging from 0.8 to 58.8 mL H 2 S/g waste, depending on the chemical composition of the samples. Selected samples contained solid phase sulfide which contributed to the measured H 2 S yield. A 60 day incubation in selected samples resulted in 39–86% additional sulfide production. H 2 S production measured in BSP assays was compared with that measured in simulated landfill reactors and that calculated from chemical analyses. H 2 S production in BSP assays and in reactors was lower than the stoichiometric values calculated from chemical composition for all wastes tested, demonstrating the importance of assays to estimate the

Molecular engineering of lanthanide ion chelating phospholipids generating assemblies with a switched magnetic susceptibility.

Science.gov (United States)

Isabettini, Stéphane; Massabni, Sarah; Hodzic, Arnel; Durovic, Dzana; Kohlbrecher, Joachim; Ishikawa, Takashi; Fischer, Peter; Windhab, Erich J; Walde, Peter; Kuster, Simon

2017-08-09

Lanthanide ion (Ln 3+ ) chelating amphiphiles are powerful molecules for tailoring the magnetic response of polymolecular assemblies. Mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine-diethylene triaminepentaacetate (DMPE-DTPA) complexed to Ln 3+ deliver highly magnetically responsive bicelles. Their magnetic properties are readily tuned by changing the bicellar size or the magnetic susceptibility Δχ of the bilayer lipids. The former technique is intrinsically bound to the region of the phase diagram guarantying the formation of bicelles. Methods aiming towards manipulating the Δχ of the bilayer are comparatively more robust, flexible and lacking. Herein, we synthesized a new Ln 3+ chelating phospholipid using glutamic acid as a backbone: DMPE-Glu-DTPA. The chelate polyhedron was specifically engineered to alter the Δχ, whilst remaining geometrically similar to DMPE-DTPA. Planar asymmetric assemblies hundreds of nanometers in size were achieved presenting unprecedented magnetic alignments. The DMPE-Glu-DTPA/Ln 3+ complex switched the Δχ, achieving perpendicular alignment of assemblies containing Dy 3+ and parallel alignment of those containing Tm 3+ . Moreover, samples with chelated Yb 3+ were more alignable than the Tm 3+ chelating counterparts. Such a possibility has never been demonstrated for planar Ln 3+ chelating polymolecular assemblies. The physico-chemical properties of these novel assemblies were further studied by monitoring the alignment behavior at different temperatures and by including 16 mol% of cholesterol (Chol-OH) in the phospholipid bilayer. The DMPE-Glu-DTPA/Ln 3+ complex and the resulting assemblies are promising candidates for applications in numerous fields including pharmaceutical technologies, structural characterization of membrane biomolecules by NMR spectroscopy, as contrasting agents for magnetic resonance imaging, and for the development of smart optical gels.

Comparison of effectiveness of four chelating agents in removing incorporated sup 241 Am

Energy Technology Data Exchange (ETDEWEB)

Mingyue, Lun; Yumin, Wang; Zhikang, Wei [Ministry of Nuclear Industry, Taiyuan, SX (China). Inst. of Radiation Protection; and others

1988-02-01

The effectiveness of four chelating agents (Ca-DTPA, Zn-DTPA, quinamic acid and H-73-10) in removing incorporated {sup 241}Am was studied on 200 rats. The results show that Ca-DTPA and Zn-DTPA are more effective than the others. They decreased the {sup 241}Am contents in the rat liver and skeleton down to only about 5 and 10 per cent of the control values, respectively. Quinamic acid has the same effectiveness in reducing the {sup 241}Am contents in the rat skeleton and liver as that of DTPA, but it leads to the cumulation of {sup 241}Am in the kidney, i. e., the {sup 241}Am content in the kidney is even higher than that in control rats. Although H-73-10 can remove {sup 241}Am from the rat organs, it is much less effective than DTPA.

Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes

Energy Technology Data Exchange (ETDEWEB)

Liu, Huan [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Luo, Guang-Qian; Hu, Hong-Yun [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Qiang; Yang, Jia-Kuan [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yao, Hong, E-mail: hyao@hust.edu.cn [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China)

2012-10-15

Highlights: Black-Right-Pointing-Pointer NH{sub 3}, SO{sub 2}, H{sub 2}S and COS are emitted during different sludge conditioning processes. Black-Right-Pointing-Pointer H{sub 2}S and SO{sub 2} generation increase in the acidic environment created by H{sub 2}SO{sub 4}. Black-Right-Pointing-Pointer Fenton peroxidation facilitates the formation of COS. Black-Right-Pointing-Pointer CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. Black-Right-Pointing-Pointer CaO leads to the conversion of free ammonia or protonated amine to volatile NH{sub 3}. - Abstract: Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH{sub 3}), sulfur dioxide (SO{sub 2}), hydrogen sulfide (H{sub 2}S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO{sub 2} and H{sub 2}S emissions in the H{sub 2}SO{sub 4} conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant

Developing an energy efficient steam reforming process to produce hydrogen from sulfur-containing fuels

Science.gov (United States)

Simson, Amanda

Hydrogen powered fuel cells have the potential to produce electricity with higher efficiency and lower emissions than conventional combustion technology. In order to realize the benefits of a hydrogen fuel cell an efficient method to produce hydrogen is needed. Currently, over 90% of hydrogen is produced from the steam reforming of natural gas. However, for many applications including fuel cell vehicles, the use of a liquid fuel rather than natural gas is desirable. This work investigates the feasibility of producing hydrogen efficiently by steam reforming E85 (85% ethanol/15% gasoline), a commercially available sulfur-containing transportation fuel. A Rh-Pt/SiO2-ZrO2 catalyst has demonstrated good activity for the E85 steam reforming reaction. An industrial steam reforming process is often run less efficiently, with more water and at higher temperatures, in order to prevent catalyst deactivation. Therefore, it is desirable to develop a process that can operate without catalyst deactivation at more energy efficient conditions. In this study, the steam reforming of a sulfur-containing fuel (E85) was studied at near stoichiometric steam/carbon ratios and at 650C, conditions at which catalyst deactivation is normally measured. At these conditions the catalyst was found to be stable steam reforming a sulfur-free E85. However, the addition of low concentrations of sulfur significantly deactivated the catalyst. The presence of sulfur in the fuel caused catalyst deactivation by promoting ethylene which generates surface carbon species (coke) that mask catalytic sites. The amount of coke increased during time on stream and became increasingly graphitic. However, the deactivation due to both sulfur adsorption and coke formation was reversible with air treatment at 650°C. However, regenerations were found to reduce the catalyst life. Air regenerations produce exotherms on the catalyst surface that cause structural changes to the catalyst. During regenerations the

Mixed and chelated waste test programs with bitumen solidification

International Nuclear Information System (INIS)

Simpson, S.I.; Morris, M.; Vidal, H.

1988-01-01

This paper presents the results of bitumen solidification tests on mixed wastes and chelated wastes. The French Atomic Energy Commission (CEA) performed demonstration tests on radioactive wastes contaminated with chelating agents for Associated Technologies, Inc. (ATI). The chelated wastes were produced and concentrated by Commonwealth Edison Co. as a result of reactor decontamination at Dresden Nuclear Station, Unit 1. Law Engineering in Charlotte, N. C. produced samples and performed tests on simulated heavy metal laden radioactive waste (mixed) to demonstrate the quality of the bituminous product. The simulation is intended to represent waste produced at Oak Ridge National Labs operated by Martin-Marietta

Color stabilization of porcine hemoglobin during spray-drying and powder storage by combining chelating and reducing agents.

Science.gov (United States)

Salvador, P; Toldrà, M; Parés, D; Carretero, C; Saguer, E

2009-10-01

This work focuses on the effects of adding a chelating agent - such as nicotinic acid (NA, 2% w/v) or nicotinamide (Nam, 2.5% w/v) - along with glucose as a reducing agent (G, 10% w/v) to fresh porcine hemoglobin in order to stabilize its red color during spray-drying and powder storage at room temperature. Correlations between the CIELAB color parameters and the relative percentages of the different hemoglobin derivatives (liganded and deliganded ferrohemoglobin, and methemoglobin) were analyzed. The results indicate that, although little effects could be observed for any of the combined treatments on fresh hemoglobin, they were effective against pigment autoxidation during dehydration and subsequent storage. From the results, it can also be concluded that glucose was the main contributor to the color stabilization of the hemoglobin powder, probably due to its high water retention capacity.

Chemistry of bifunctional photoprobes. 3 -- Correlation between the efficiency of CH insertion by photolabile chelating agents and lifetimes of singlet nitrenes by flash photolysis: First example of photochemical attachment of 99mTc-complex with human serum albumin

International Nuclear Information System (INIS)

Pandurangi, R.S.; Lusiak, P.; Kuntz, R.R.; Volkert, W.A.; Rogowski, J.; Platz, M.S.

1998-01-01

Systematic functionalization of perfluoroaryl azides with chelating agents capable of complexing transition metals produces a new class of bifunctional photolabile chelating agents (BFPCAs). The strategy is shield the azide functionality from the electronic and steric influence of the electron-rich metal Pd through ester and amide bridges raised CH insertion efficiency to unprecedented levels (>92%) in a model solvent (cyclohexane). In contrast, perfluoroaryl azides attached to chelating agents via hydrazones show no significant CH insertion in cyclohexane upon photolysis. Measurements of the lifetimes of the singlet nitrenes derived from these agents by flash photolysis techniques correlate well with the efficiency of CH insertion by demonstrating longer lifetimes (10--50 times) for singlet nitrenes derived from azidotetrafluorinated esters and amides compared with the related hydrazones, which failed to yield significant CH insertion. A representative BFPCA 12 is chelated to diagnostic radionuclide 99m Tc and covalently attached to human serum albumin via photochemical activation extending the favorable bimolecular insertion characteristics of BFPCA to tracer level concentrations in buffer conditions. Flash photolysis experiments correlate singlet nitrene lifetimes with the efficiency of intermolecular insertion reactions. This work provides new photo-cross-linking technology, useful in radiodiagnostics and radiotherapy in nuclear medicine

Biotransformation of nitrogen- and sulfur-containing pollutants during coking wastewater treatment: Correspondence of performance to microbial community functional structure.

Science.gov (United States)

Joshi, Dev Raj; Zhang, Yu; Gao, Yinxin; Liu, Yuan; Yang, Min

2017-09-15

Although coking wastewater is generally considered to contain high concentration of nitrogen- and sulfur-containing pollutants, the biotransformation processes of these compounds have not been well understood. Herein, a high throughput functional gene array (GeoChip 5.0) in combination with Illumina MiSeq sequencing of the 16S rRNA gene were used to identify microbial functional traits and their role in biotransformation of nitrogen- and sulfur-containing compounds in a bench-scale aerobic coking wastewater treatment system operated for 488 days. Biotransformation of nitrogen and sulfur-containing pollutants deteriorated when pH of the bioreactor was increased to >8.0, and the microbial community functional structure was significantly associated with pH (Mantels test, P functional microbial community structure (P functional genes for biotransformation of nitrogen- and sulfur-containing pollutants. Functional characterization of taxa and network analysis suggested that Burkholderiales, Actinomycetales, Rhizobiales, Pseudomonadales, and Hydrogenophiliales (Thiobacillus) were key functional taxa. Variance partitioning analysis showed that pH and influent ammonia nitrogen jointly explained 25.9% and 35.5% of variation in organic pollutant degrading genes and microbial community structure, respectively. This study revealed a linkage between microbial community functional structure and the likely biotransformation of nitrogen- and sulfur-containing pollutants, along with a suitable range of pH (7.0-7.5) for stability of the biological system treating coking wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dispersive liquid–liquid microextraction using diethyldithiocarbamate as a chelating agent and the dried-spot technique for the determination of Fe, Co, Ni, Cu, Zn, Se and Pb by energy-dispersive X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Kocot, Karina; Zawisza, Beata; Sitko, Rafal

2012-01-01

Dispersive liquid–liquid microextraction (DLLME) using sodium diethyldithiocarbamate (DDTC) as a chelating agent was investigated for the simultaneous determination of iron, cobalt, nickel, copper, zinc, selenium and lead ions in water samples. The procedure was performed using 5 mL of the sample, 100 μL of a 0.5% solution of DDTC, 30 μL of carbon tetrachloride (extraction phase) and 500 μL of methanol (disperser solvent). The experiments showed that Fe, Co, Ni, Cu, Zn and Pb can be simultaneously extracted at a pH of 5 and that Se can be extracted at a pH of 2–3. The results were compared with those obtained using ammonium pyrrolidine dithiocarbamate as a chelating agent. For all analytes, a linear range was observed up to 0.4 μg mL −1 . If Fe and Zn are present in concentrations 10 times higher than those of the other analytes, then the linearity is observed up to 0.2 μg mL −1 . In the present study, the organic phase that contained preconcentrated elements was deposited onto a Millipore filter and measured using energy-dispersive X-ray fluorescence spectrometry. The obtained detection limits were 2.9, 1.5, 2.0, 2.3, 2.5, 2.0 and 3.9 ng mL −1 for Fe, Co, Ni, Cu, Zn, Se and Pb, respectively. This combination of DLLME and the dried-spot technique is promising for multielement analyses using other spectroscopy techniques, such as laser ablation‐inductively coupled plasma‐mass spectrometry, laser-induced breakdown spectroscopy or total-reflection X-ray fluorescence spectrometry. - Highlights: ► Multielement trace analysis using dried-spot technique and dispersive liquid–liquid microextraction. ► Possibility of combination of LPME with EDXRF, LIBS or LA-ICP-MS. ► Comparison of APDC and DDTC as chelating agents.

A batch assay to measure microbial hydrogen sulfide production from sulfur-containing solid wastes

Energy Technology Data Exchange (ETDEWEB)

Sun, Mei, E-mail: msun8@uncc.edu [Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Campus Box 7908, Raleigh, NC (United States); Sun, Wenjie, E-mail: wsun@smu.edu [Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Campus Box 7908, Raleigh, NC (United States); Department of Civil and Environmental Engineering, Southern Methodist University, PO Box 750340, Dallas, TX (United States); Barlaz, Morton A., E-mail: barlaz@ncsu.edu [Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Campus Box 7908, Raleigh, NC (United States)

2016-05-01

Large volumes of sulfur-containing wastes enter municipal solid waste landfills each year. Under the anaerobic conditions that prevail in landfills, oxidized forms of sulfur, primarily sulfate, are converted to sulfide. Hydrogen sulfide (H{sub 2}S) is corrosive to landfill gas collection and treatment systems, and its presence in landfill gas often necessitates the installation of expensive removal systems. For landfill operators to understand the cost of managing sulfur-containing wastes, an estimate of the H{sub 2}S production potential is needed. The objective of this study was to develop and demonstrate a biochemical sulfide potential (BSP) test to measure the amount of H{sub 2}S produced by different types of sulfur-containing wastes in a relatively fast (30 days) and inexpensive (125 mL serum bottles) batch assay. This study confirmed the toxic effect of H{sub 2}S on both sulfate reduction and methane production in batch systems, and demonstrated that removing accumulated H{sub 2}S by base adsorption was effective for mitigating inhibition. H{sub 2}S production potentials of coal combustion fly ash, flue gas desulfurization residual, municipal solid waste combustion ash, and construction and demolition waste were determined in BSP assays. After 30 days of incubation, most of the sulfate in the wastes was converted to gaseous or aqueous phase sulfide, with BSPs ranging from 0.8 to 58.8 mL H{sub 2}S/g waste, depending on the chemical composition of the samples. Selected samples contained solid phase sulfide which contributed to the measured H{sub 2}S yield. A 60 day incubation in selected samples resulted in 39–86% additional sulfide production. H{sub 2}S production measured in BSP assays was compared with that measured in simulated landfill reactors and that calculated from chemical analyses. H{sub 2}S production in BSP assays and in reactors was lower than the stoichiometric values calculated from chemical composition for all wastes tested, demonstrating

Synthesis and evaluation of novel bifunctional chelating agents based on 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid for radiolabeling proteins

International Nuclear Information System (INIS)

Chappell, L.L.; Ma, D.; Milenic, D.E.; Garmestani, K.; Venditto, V.; Beitzel, M.P.; Brechbiel, M.W.

2003-01-01

Detailed synthesis of the bifunctional chelating agents 2-methyl-6-(p-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10 -tetraacetic acid (1B4M-DOTA) and 2-(p-isothiocyanatobenzyl)-5, 6-cyclohexano-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetate (CHX-DOTA) are reported. These chelating agents were compared to 2-(p-isothiocyanatobenzyl)-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (C-DOTA) and 1, 4, 7, 10-Tetraaza-N-(1-carboxy-3-(4-nitrophenyl)propyl)-N', N'', N'''-tris(acetic acid) cyclododecane (PA-DOTA) as their 177 Lu radiolabeled conjugates with Herceptin TM . In vitro stability of the immunoconjugates radiolabeled with 177 Lu was assessed by serum stability studies. The in vivo stability of the radiolabeled immunoconjugates and their targeting characteristics were determined by biodistribution studies in LS-174T xenograft tumor-bearing mice. Relative radiolabeling rates and efficiencies were determined for all four immunoconjugates. Insertion of the 1B4M moiety into the DOTA backbone increases radiometal chelation rate and provides complex stability comparable to C-DOTA and PA-DOTA while the CHX-DOTA appears to not form as stable a 177 Lu complex while exhibiting a substantial increase in formation rate. The 1B4M-DOTAmay have potential for radioimmunotherapy applications. Published by Elsevier Inc. All rights reserved

Iron Chelators and Antioxidants Regenerate Neuritic Tree and Nigrostriatal Fibers of MPP+/MPTP-Lesioned Dopaminergic Neurons.

Directory of Open Access Journals (Sweden)

Pabla Aguirre

Full Text Available Neuronal death in Parkinson's disease (PD is often preceded by axodendritic tree retraction and loss of neuronal functionality. The presence of non-functional but live neurons opens therapeutic possibilities to recover functionality before clinical symptoms develop. Considering that iron accumulation and oxidative damage are conditions commonly found in PD, we tested the possible neuritogenic effects of iron chelators and antioxidant agents. We used three commercial chelators: DFO, deferiprone and 2.2'-dypyridyl, and three 8-hydroxyquinoline-based iron chelators: M30, 7MH and 7DH, and we evaluated their effects in vitro using a mesencephalic cell culture treated with the Parkinsonian toxin MPP+ and in vivo using the MPTP mouse model. All chelators tested promoted the emergence of new tyrosine hydroxylase (TH-positive processes, increased axodendritic tree length and protected cells against lipoperoxidation. Chelator treatment resulted in the generation of processes containing the presynaptic marker synaptophysin. The antioxidants N-acetylcysteine and dymetylthiourea also enhanced axodendritic tree recovery in vitro, an indication that reducing oxidative tone fosters neuritogenesis in MPP+-damaged neurons. Oral administration to mice of the M30 chelator for 14 days after MPTP treatment resulted in increased TH- and GIRK2-positive nigra cells and nigrostriatal fibers. Our results support a role for oral iron chelators as good candidates for the early treatment of PD, at stages of the disease where there is axodendritic tree retraction without neuronal death.

Biomedical tracers: technetium-99 m complexing sulfur polydentate ligands

International Nuclear Information System (INIS)

Bendennoune, A.

1994-01-01

Cyclic and acyclic tetra sulfur ligands have been synthesized and some of them have been labelled with technetium-99m. These works have two different aims: 1- Development of methods permitting to obtain easily potential technetium complexing sulfur polydentate chelates. 2- Research of positive and neutral complexes of this metal likely to replace thalium-201 in the coronary flow estimation and [TcO-HMPAO] sup 0 complex in the cerebral scintigraphy, respectively. In this work, first, different ways for obtaining dithioetherdithiols and cyclic tetrathioethers containing functional groups have been carried out, then complexation of the core of nitrutechnetium (TcN) sup 2+ at tracers scale, by dithioetherdithiols, using exchange reaction with [sup 9 sup 9 sup m TcNCl sub 4 ] sup - ion complex or sup 99 sup m TcN Cl sub 2 [P(CH sub 2 CH sub 2 CN) sub 3 ] sub 2 has been studied. Finally, biological distribution in swiss mouse of these technetiated complexes has been studied. 135 refs., 30 figs., 13 tabs. (F.M.)

Radiopharmaceutical chelates and method of external imaging

International Nuclear Information System (INIS)

Loberg, M.D.; Callery, P.S.; Cooper, M.

1977-01-01

A chelate of technetium-99m, cobalt-57, gallium-67, gallium-68, indium-111 or indium-113m and a substituted iminodiacetic acid or an 8-hydroxyquinoline useful as a radiopharmaceutical external imaging agent. The invention also includes preparative methods therefor

Mechanical and Electrical Properties of Sulfur-Containing Polymeric Materials Prepared via Inverse Vulcanization

Directory of Open Access Journals (Sweden)

Sergej Diez

2017-02-01

Full Text Available Recently, new methods have been developed for the utilization of elemental sulfur as a feedstock for novel polymeric materials. One promising method is the inverse vulcanization, which is used to prepare polymeric structures derived from sulfur and divinyl comonomers. However, the mechanical and electrical properties of the products are virtually unexplored. Hence, in the present study, we synthesized a 200 g scale of amorphous, hydrophobic as well as translucent, hyperbranched polymeric sulfur networks that provide a high thermal resistance (>220 °C. The polymeric material properties of these sulfur copolymers can be controlled significantly by varying the monomers as well as the feed content. The investigated comonomers are divinylbenzene (DVB and 1,3-diisopropenylbenzene (DIB. Plastomers with low elastic content and high shape retention containing 12.5%–30% DVB as well as low viscose waxy plastomers with a high flow behavior containing a high DVB content of 30%–35% were obtained. Copolymers with 15%–30% DIB act, on the one hand, as thermoplastics and, on the other hand, as vitreous thermosets with a DIB of 30%–35%. Results of the thermogravimetric analysis (TGA, the dynamic scanning calorimetry (DSC and mechanical characterization, such as stress–strain experiments and dynamic mechanical thermal analysis, are discussed with the outcome that they support the assumption of a polymeric cross-linked network structure in the form of hyper-branched polymers.

New method for studying the efficiency of chelating agents of the polyamine acid series for internal decontamination; Methode nouvelle d'etude de l'efficacite des chelateurs de la serie des acides polyamines pour la decontamination interne

Energy Technology Data Exchange (ETDEWEB)

Lafuma, J; Nenot, J C; Morin, M [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1968-07-01

We followed the biological fate of a complex formed on one side with either a rare earth (cerium-144) or a transuranium element (plutonium-239), and on the other side with a chelating agent of the polyamino acid series (EDTA, BAETA, DTPA, TTHA). This method allowed to study: 1 - the in vivo stability of the various complexes and to compare them; 2 - the stability of the complexes as a function of the isotope - chelating agent weight relationships; 3 - the metabolism of the chelating agents resulting in stable complexes, i. e. DTPA and TTHA mainly. This simple method brought out the higher efficiency, of DTPA in chelating rare earths and plutonium and for therapeutic purposes. (authors) [French] La methode consiste a suivre le devenir biologique d'un complexe forme d'une part avec une terre rare (cerium 144) ou un transuranien (plutonium 239) et d'autre part avec un chelateur de la serie des acides polyamines (EDTA, BAETA, DTPA, TTHA). Elle permet d'etudier: 1 - la stabilite in vivo des differents complexes, de les comparer; 2 - la stabilite des complexes en fonction des rapports ponderaux isotope - chelateurs; 3 - le metabolisme des chelateurs formant des complexes stables, essentiellement DTPA et TTHA. Cette methode simple degage la suprematie du DTPA en ce qui concerne la chelation des terres rares et du plutonium, et son utilisation a des fins therapeutiques. (auteurs)

Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries

Energy Technology Data Exchange (ETDEWEB)

Liang, Chengdu; Dudney, Nancy J.; Howe, Jane Y.

2017-08-01

The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.

Photo-Fenton treatment of saccharin in a solar pilot compound parabolic collector: Use of olive mill wastewater as iron chelating agent, preliminary results.

Science.gov (United States)

Davididou, K; Chatzisymeon, E; Perez-Estrada, L; Oller, I; Malato, S

2018-03-14

The aim of this work was to investigate the treatment of the artificial sweetener saccharin (SAC) in a solar compound parabolic collector pilot plant by means of the photo-Fenton process at pH 2.8. Olive mill wastewater (OMW) was used as iron chelating agent to avoid acidification of water at pH 2.8. For comparative purposes, Ethylenediamine-N, N-disuccinic acid (EDDS), a well-studied iron chelator, was also employed at circumneutral pH. Degradation products formed along treatment were identified by LC-QTOF-MS analysis. Their degradation was associated with toxicity removal, evaluated by monitoring changes in the bioluminescence of Vibrio fischeri bacteria. Results showed that conventional photo-Fenton at pH 2.8 could easily degrade SAC and its intermediates yielding k, apparent reaction rate constant, in the range of 0.64-0.82 L kJ -1 , as well as, eliminate effluent's chronic toxicity. Both OMW and EDDS formed iron-complexes able to catalyse H 2 O 2 decomposition and generate HO. OMW yielded lower SAC oxidation rates (k = 0.05-0.1 L kJ -1 ) than EDDS (k = 2.21-7.88 L kJ -1 ) possibly due to its higher TOC contribution. However, the degradation rates were improved (k = 0.13 L kJ -1 ) by increasing OMW dilution in the reactant mixture. All in all, encouraging results were obtained by using OMW as iron chelating agent, thus rendering this approach promising towards the increase of process sustainability. Copyright © 2018 Elsevier B.V. All rights reserved.

Efficacy of HOCl scavenging by sulfur-containing compounds: antioxidant activity of glutathione disulfide?

NARCIS (Netherlands)

den Hartog, G.J.M.; Haenen, G.R.M.M.; Vegt, E.; van der Vijgh, W.J.F.; Bast, A.

2002-01-01

Efficacy of HOCl scavenging by sulfur-containing compounds: antioxidant activity of glutathione disulfide? den Hartog GJ, Haenen GR, Vegt E, van der Vijgh WJ, Bast A. Department of Pharmacology and Toxicology, Maastricht University, The Netherlands. Hypochlorous acid (HOCl) is a bactericidal

Quantitative structure-property relationship (correlation analysis) of phosphonic acid-based chelates in design of MRI contrast agent.

Science.gov (United States)

Tiwari, Anjani K; Ojha, Himanshu; Kaul, Ankur; Dutta, Anupama; Srivastava, Pooja; Shukla, Gauri; Srivastava, Rakesh; Mishra, Anil K

2009-07-01

Nuclear magnetic resonance imaging is a very useful tool in modern medical diagnostics, especially when gadolinium (III)-based contrast agents are administered to the patient with the aim of increasing the image contrast between normal and diseased tissues. With the use of soft modelling techniques such as quantitative structure-activity relationship/quantitative structure-property relationship after a suitable description of their molecular structure, we have studied a series of phosphonic acid for designing new MRI contrast agent. Quantitative structure-property relationship studies with multiple linear regression analysis were applied to find correlation between different calculated molecular descriptors of the phosphonic acid-based chelating agent and their stability constants. The final quantitative structure-property relationship mathematical models were found as--quantitative structure-property relationship Model for phosphonic acid series (Model 1)--log K(ML) = {5.00243(+/-0.7102)}- MR {0.0263(+/-0.540)}n = 12 l r l = 0.942 s = 0.183 F = 99.165 quantitative structure-property relationship Model for phosphonic acid series (Model 2)--log K(ML) = {5.06280(+/-0.3418)}- MR {0.0252(+/- .198)}n = 12 l r l = 0.956 s = 0.186 F = 99.256.

Oxidation of refractory sulfur compounds over Ti-containing mesoporous molecular sieves prepared by using a fluorosilicon compound.

Science.gov (United States)

Jeong, Kwang-Eun; Cho, Chin-Soo; Chae, Ho-Jeong; Kim, Chul-Ung; Jeong, Soon-Yong

2010-05-01

Titanium containing mesoporous molecular sieve (Ti-MMS) catalysts were studied for the oxidative desulfurization of refractory sulfur compounds. Ti-MMS catalysts were synthesized from fluorosilicon compounds and Ti with the hydrolysis reaction of H2SiF6 in an ammonia-surfactant mixed solution. The solid products were characterized by XRD, XRF, nitrogen adsorption, and diffuse reflectance UV-vis spectroscopy. Effects of Ti loading and oxidant/sulfur mole ratio, and sulfur species on ODS activity were investigated.

Heavy Metal Displacement in Chelate-Assisted Phytoremediation of Biosolids Soil

Science.gov (United States)

Kirkham, M. B.; Liphadzi, M. S.

2005-05-01

Heavy metals in biosolids (sewage sludge) applied to land contaminate the soil. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with biosolids following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals, as affected by a chelate, in soil (Haynie very fine sandy loam) from a 25-year old sludge farm. Soil columns (105 cm long; 39 cm in diameter) either had a plant (hybrid poplar; Populus deltoides Marsh. x P. nigra L.) or no plant. When the poplars were 144 days old, the tetrasodium salt of the chelating agent EDTA (ethylenediamine-tetraacetic acid) was irrigated onto the soil at a rate of 1 g per kg of soil. Drainage water, soil, and plants were analyzed for three toxic heavy metals (Cd, Ni, Pb) and four essential heavy metals (Cu, Fe, Mn, Zn). Without EDTA, concentrations of the seven heavy metals in the leachate from columns with or without plants were low or below detection limits. With or without plants, the EDTA mobilized all heavy metals and increased their concentration in drainage water. Without plants, the concentrations of Cd, Cu, Fe, Pb, and Zn in the leachate from columns with EDTA were above drinking-water standards. (There is no drinking-water standard for Ni.) The presence of poplar plants in the soil reduced the concentrations of Cu, Fe, and Zn in the leachate so it fell within drinking-water standards. Concentrations of Cd and Pb in the leachate remained above drinking-water standards with or without plants. At harvest (124 days after the EDTA application), total concentration of each heavy metal in the soil at different depths in the columns with EDTA was similar to that in the columns without EDTA. The chelate did not affect the concentration of heavy metals in the roots, stems, or leaves

Self-assembled polymeric chelate nanoparticles as potential theranostic agents

Czech Academy of Sciences Publication Activity Database

Škodová, Michaela; Černoch, Peter; Štěpánek, Petr; Chánová, Eliška; Kučka, Jan; Kálalová, Zuzana; Kaňková, Dana; Hrubý, Martin

2012-01-01

Roč. 13, č. 18 (2012), s. 4244-4250 ISSN 1439-4235 R&D Projects: GA ČR GPP207/10/P054; GA ČR GA202/09/2078; GA ČR GAP304/12/0950 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : chelate s * nanoparticles * polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.349, year: 2012

The use of chelating agents in the remediation of metal-contaminated soils: A review

Energy Technology Data Exchange (ETDEWEB)

Lestan, Domen [Agronomy Department, Centre for Soil and Environmental Science, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana (Slovenia); Luo Chunling [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Li Xiangdong [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)], E-mail: cexdli@polyu.edu.hk

2008-05-15

This paper reviews current remediation technologies that use chelating agents for the mobilization and removal of potentially toxic metals from contaminated soils. These processes can be done in situ as enhanced phytoextraction, chelant enhanced electrokinetic extraction and soil flushing, or ex situ as the extraction of soil slurry and soil heap/column leaching. Current proposals on how to treat and recycle waste washing solutions after soil is washed are discussed. The major controlling factors in phytoextraction and possible strategies for reducing the leaching of metals associated with the application of chelants are also reviewed. Finally, the possible impact of abiotic and biotic soil factors on the toxicity of metals left after the washing of soil and enhanced phytoextraction are briefly addressed. - The use of synthetic chelants for soil washing and enhanced phytoextraction by plants has been well studied for the remediation of metal-contaminated soils in the last two decades.

The use of chelating agents in the remediation of metal-contaminated soils: A review

International Nuclear Information System (INIS)

Lestan, Domen; Luo Chunling; Li Xiangdong

2008-01-01

This paper reviews current remediation technologies that use chelating agents for the mobilization and removal of potentially toxic metals from contaminated soils. These processes can be done in situ as enhanced phytoextraction, chelant enhanced electrokinetic extraction and soil flushing, or ex situ as the extraction of soil slurry and soil heap/column leaching. Current proposals on how to treat and recycle waste washing solutions after soil is washed are discussed. The major controlling factors in phytoextraction and possible strategies for reducing the leaching of metals associated with the application of chelants are also reviewed. Finally, the possible impact of abiotic and biotic soil factors on the toxicity of metals left after the washing of soil and enhanced phytoextraction are briefly addressed. - The use of synthetic chelants for soil washing and enhanced phytoextraction by plants has been well studied for the remediation of metal-contaminated soils in the last two decades

Simultaneous Determination of Chelating Agents by Ion-Suppression and Ion-Pair Chromatography in Wastewater

International Nuclear Information System (INIS)

Dodi, Alain; Bouscarel, Maelle

2008-01-01

This article describes two methods for analysing chelating agents found in nuclear waste. First, ion-suppression chromatography using an anion exchange stationary phase and mobile phase consisting of a nitric acid solution and pure water gradient. UV detection was performed at 330 nm after the reaction with a post-column reagent composed of iron nitrate in perchloric acid. Secondly, ion-pair chromatography with a mobile phase consisting of a mixture of nitric acid, tetra-butyl-ammonium hydrogeno-sulphate, tetra-butyl-ammonium hydroxide and iron chloride. A reversed-phase material was used as a stationary phase and detection was performed by direct measurement of the UV absorption at 260 nm. The quantification limits were lower for ion-pair chromatography than for ion-suppression chromatography. Both methods were easy to implement and allow a multi-element separation in less than 30 min with low detection limits. (authors)

Simultaneous Determination of Chelating Agents by Ion-Suppression and Ion-Pair Chromatography in Wastewater

Energy Technology Data Exchange (ETDEWEB)

Dodi, Alain; Bouscarel, Maelle [Commissariat a l' energie atomique - C.E.A, Centre d' Etude de Cadarache, Laboratoire d' Analyses Radiochimiques et Chimiques, St Paul lez Durance (France)

2008-07-01

This article describes two methods for analysing chelating agents found in nuclear waste. First, ion-suppression chromatography using an anion exchange stationary phase and mobile phase consisting of a nitric acid solution and pure water gradient. UV detection was performed at 330 nm after the reaction with a post-column reagent composed of iron nitrate in perchloric acid. Secondly, ion-pair chromatography with a mobile phase consisting of a mixture of nitric acid, tetra-butyl-ammonium hydrogeno-sulphate, tetra-butyl-ammonium hydroxide and iron chloride. A reversed-phase material was used as a stationary phase and detection was performed by direct measurement of the UV absorption at 260 nm. The quantification limits were lower for ion-pair chromatography than for ion-suppression chromatography. Both methods were easy to implement and allow a multi-element separation in less than 30 min with low detection limits. (authors)

New method for studying the efficiency of chelating agents of the polyamine acid series for internal decontamination; Methode nouvelle d'etude de l'efficacite des chelateurs de la serie des acides polyamines pour la decontamination interne

Energy Technology Data Exchange (ETDEWEB)

Lafuma, J.; Nenot, J.C.; Morin, M. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1968-07-01

We followed the biological fate of a complex formed on one side with either a rare earth (cerium-144) or a transuranium element (plutonium-239), and on the other side with a chelating agent of the polyamino acid series (EDTA, BAETA, DTPA, TTHA). This method allowed to study: 1 - the in vivo stability of the various complexes and to compare them; 2 - the stability of the complexes as a function of the isotope - chelating agent weight relationships; 3 - the metabolism of the chelating agents resulting in stable complexes, i. e. DTPA and TTHA mainly. This simple method brought out the higher efficiency, of DTPA in chelating rare earths and plutonium and for therapeutic purposes. (authors) [French] La methode consiste a suivre le devenir biologique d'un complexe forme d'une part avec une terre rare (cerium 144) ou un transuranien (plutonium 239) et d'autre part avec un chelateur de la serie des acides polyamines (EDTA, BAETA, DTPA, TTHA). Elle permet d'etudier: 1 - la stabilite in vivo des differents complexes, de les comparer; 2 - la stabilite des complexes en fonction des rapports ponderaux isotope - chelateurs; 3 - le metabolisme des chelateurs formant des complexes stables, essentiellement DTPA et TTHA. Cette methode simple degage la suprematie du DTPA en ce qui concerne la chelation des terres rares et du plutonium, et son utilisation a des fins therapeutiques. (auteurs)

Metal regeneration of iron chelates in nitric oxide scrubbing

Science.gov (United States)

Chang, S.G.; Littlejohn, D.; Shi, Y.

1997-08-19

The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

New treating processes for sulfur-containing natural gases

Energy Technology Data Exchange (ETDEWEB)

Kislenko, N.; Aphanasiev, A.; Nabokov, S.; Ismailova, H. [VNIIGAS, Moscow (Russian Federation)

1996-12-31

The traditional method of removing H{sub 2}S from sour natural gases is first to treat the gas with a solvent and then to recover the H{sub 2}S from the sour stream in a Claus plant. This method recovers up to 97% of the sulfur when a three-stage Claus unit is employed. Amine/Claus units have operating difficulties for small sulfur capacities (up to 5 tons/day) because the operation of the fired equipment (reaction furnace) is much more difficult. Therefore, for small scale sulfur recovery plants redox processes which exhibit a significant reduction in investment and operating costs are normally used. Many different factors influence the choice of gas desulfurization technology--composition and gas flow, environmental sulfur recovery requirements and CO{sub 2}/H{sub 2}S ratio.

Degradation of solid oxide fuel cell metallic interconnects in fuels containing sulfur

Energy Technology Data Exchange (ETDEWEB)

Ziomek-Moroz, M.; Hawk, Jeffrey A.

2005-01-01

Hydrogen is the main fuel for all types of fuel cells except direct methanol fuel cells. Hydrogen can be generated from all manner of fossil fuels, including coal, natural gas, diesel, gasoline, other hydrocarbons, and oxygenates (e.g., methanol, ethanol, butanol, etc.). Impurities in the fuel can cause significant performance problems and sulfur, in particular, can decrease the cell performance of fuel cells, including solid oxide fuel cells (SOFC). In the SOFC, the high (800-1000°C) operating temperature yields advantages (e.g., internal fuel reforming) and disadvantages (e.g., material selection and degradation problems). Significant progress in reducing the operating temperature of the SOFC from ~1000 ºC to ~750 ºC may allow less expensive metallic materials to be used for interconnects and as balance of plant (BOP) materials. This paper provides insight on the material performance of nickel, ferritic steels, and nickel-based alloys in fuels containing sulfur, primarily in the form of H2S, and seeks to quantify the extent of possible degradation due to sulfur in the gas stream.

A binder-free sulfur/reduced graphene oxide aerogel as high performance electrode materials for lithium sulfur batteries

Science.gov (United States)

Nitze, Florian; Agostini, Marco; Lundin, Filippa; Palmqvist, Anders E. C.; Matic, Aleksandar

2016-12-01

Societies’ increasing need for energy storage makes it necessary to explore new concepts beyond the traditional lithium ion battery. A promising candidate is the lithium-sulfur technology with the potential to increase the energy density of the battery by a factor of 3-5. However, so far the many problems with the lithium-sulfur system have not been solved satisfactory. Here we report on a new approach utilizing a self-standing reduced graphene oxide based aerogel directly as electrodes, i.e. without further processing and without the addition of binder or conducting agents. We can thereby disrupt the common paradigm of “no battery without binder” and can pave the way to a lithium-sulfur battery with a high practical energy density. The aerogels are synthesized via a one-pot method and consist of more than 2/3 sulfur, contained inside a porous few-layered reduced graphene oxide matrix. By combining the graphene-based aerogel cathode with an electrolyte and a lithium metal anode, we demonstrate a lithium-sulfur cell with high areal capacity (more than 3 mAh/cm2 after 75 cycles), excellent capacity retention over 200 cycles and good sulfur utilization. Based on this performance we estimate that the energy density of this concept-cell can significantly exceed the Department of Energy (DEO) 2020-target set for transport applications.

Toxicology Studies on Lewisite and Sulfur Mustard Agents: Subchronic Toxicity of Sulfur Mustard (HD) In Rats Final Report

Energy Technology Data Exchange (ETDEWEB)

Sasser, L. B.; Miller, R. A.; Kalkwarf, D, R.; Buschbom, R. L.; Cushing, J. A.

1989-06-30

Occupational health standards have not been established for sulfur mustard [bis(2- chlorethyl)-sulfide], a strong alkylating agent with known mutagenic properties. Seventytwo Sprague-Dawley rats of each sex, 6-7 weeks old, were divided into six groups (12/group/ sex) and gavaged with either 0, 0.003 , 0.01 , 0.03 , 0.1 or 0.3 mg/kg of sulfur mustard in sesame oil 5 days/week for 13 weeks. No dose-related mortality was observed. A significant decrease (P ( 0.05) in body weight was observed in both sexes of rats only in the 0.3 mg/kg group. Hematological evaluations and clinical chemistry measurements found no consistent treatment-related effects at the doses studied. The only treatment-related lesion associated with gavage exposure upon histopathologic evaluation was epithelial hyperplasia of the forestomach of both sexes at 0.3 mg/kg and males at 0.1 mg/kg. The hyperplastic change was minimal and characterized by cellular disorganization of the basilar layer, an apparent increase in mitotic activity of the basilar epithelial cells, and thickening of the epithelial layer due to the apparent increase in cellularity. The estimated NOEL for HD in this 90-day study is 0.1 mg/kg/day when administered orally.

Improved paramagnetic chelate for molecular imaging with MRI

International Nuclear Information System (INIS)

Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

2005-01-01

The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent

Improved paramagnetic chelate for molecular imaging with MRI

Science.gov (United States)

Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

2005-05-01

The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS

Energy Technology Data Exchange (ETDEWEB)

Abergel, Rebecca J.; Raymond, Kenneth N.

2011-07-13

The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.

Effects of elemental sulfur and sulfur-containing waste on nutrient ...

African Journals Online (AJOL)

STORAGESEVER

2009-09-15

Sep 15, 2009 ... grown twice on the same soils to determine initial and residual effects of applied S. Results showed that applications of ... Key words: Calcareous soil, plant growth, plant nutrition, sulfur application. ...... Colombia. Can. J. Soil ...

Obligatory reduction of ferric chelates in iron uptake by soybeans.

Science.gov (United States)

Chaney, R L; Brown, J C; Tiffin, L O

1972-08-01

The contrasting Fe(2+) and Fe(3+) chelating properties of the synthetic chelators ethylenediaminedi (o-hydroxyphenylacetate) (EDDHA) and 4,7-di(4-phenylsulfonate)-1, 10-phenanthroline (bathophenanthrolinedisulfonate) (BPDS) were used to determine the valence form of Fe absorbed by soybean roots supplied with Fe(3+)-chelates. EDDHA binds Fe(3+) strongly, but Fe(2+) weakly; BPDS binds Fe(2+) strongly but Fe(3+) weakly. Addition of an excess of BPDS to nutrient solutions containing Fe(3+)-chelates inhibited soybean Fe uptake-translocation by 99+%; [Fe(II) (BPDS)(3)](4-) accumulated in the nutrient solution. The addition of EDDHA caused little or no inhibition. These results were observed with topped and intact soybeans. Thus, separation and absorption of Fe from Fe(3+)-chelates appear to require reduction of Fe(3+)-chelate to Fe(2+)-chelate at the root, with Fe(2+) being the principal form of Fe absorbed by soybean.

Chelation therapy in intoxications with mercury, lead and copper

DEFF Research Database (Denmark)

Cao, yang; Skaug, Marit Aralt; Andersen, Ole

2015-01-01

In the present review we provide an update of the appropriate use of chelating agents in the treatment of intoxications with compounds of mercury, lead and copper. The relatively new chelators meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-propanesulphonate (DMPS) can effectively...... mobilize deposits of mercury as well as of lead into the urine. These drugs can be administered orally and have relatively low toxicity compared to the classical antidote dimercaptopropanol (BAL). d-Penicillamine has been widely used in copper overload, although 2,3-dimercaptosuccinic acid...

Heavy metal displacement in chelate-irrigated soil during phytoremediation

Science.gov (United States)

Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

2003-03-01

Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

The experimental study on protective effects and mechanisms of chelating agents of catechols amino carboxylic acid for radiation injury induced by actimides(Th-234)

International Nuclear Information System (INIS)

Chen, H. H.; Luo, M. C.; Sun, M. Z.; Hu, Y. X.; Wang, Y. H.; Jin, M. Y.; Cheng, W. Y.

2002-01-01

The decorporative efficacy and antioxidative action of prompt and delayed consecutive administration of catecholicpolyaminopolycarboxylate ligands, 7601 and 9501 for radiothorium in mice were investigated. DTPA and Vitamin E were used as positive controls. The competitive abilities of 7601 and 9501 to mobilize the thorium with BSA were studied. Their inhibition effects on superoxide anionas radicals were measured with electron spin resonance. The results showed that 7601 and 9501 are able to effectively prevent the internal radiation injury induced radiothorium, attributing to their double functions of pronounced removal effectiveness and antioxidative action. Their protective effects were better than DTPA and Vitamin E. The mechanisms of protective effects of 7601 and 9501 for internal radiation injury was close related to competitive ability of chelating agent to chelate the thorium with BSA and oxygen free radical scavenging activities

Development of a new radiolabel (lead-203) and new chelating agents for labeling monoclonal anntibodies for imaging

International Nuclear Information System (INIS)

Srivastava, S.C.; Mease, R.C.; Meinken, G.E.; Mausner, L.F.; Steplewski, Z.

1988-01-01

High liver uptake and slow body clearance presently limit the usefulness of 111 In labeled antibodies for tumor imaging. We have investigated 203 Pb as an alternate and better antibody label. The DTPA and cyclohexyl EDTA (CDTA) conjugates of an anticolon carcinoma antibody, 17-1A were labeled (bicyclic anhydride method) with 203 Pb and 111 In with 60 and 90% labeling yields, respectively. The biodistribution of 203 Pb-17-1A conjugates was compared with the corresponding 111 In-labeled preparations and with 203 Pb-DTPA, 203 Pb-nitrate and nonrelevant antibody controls in normal and human tumor (SW948) xenografted nude mice at 24, and 96 hr. Lead-203-labeled CDTA and DTPA antibody conjugates gave similar in vivo distributions. Even though the lead bound to these chelate-antibody conjugates was more labile in serum and in vivo, compared to indium, it cleared much faster from the liver and the whole body. A new series of chelating agents based on the incorporation of a trans-1,2- diaminocyclohexane moiety into the carbon backbone of polyaminocarboxylates is being synthesized. These are expected to provide stronger complexing ability for lead and produce greater in vivo stability. These ligands are also expected to be superior to EDTA and DTPA for labeling antibodies with other radiometals, including indium. 32 refs., 3 tabs

Diagnostic compositions containing a chelate of radioactive indium and 8-hydroxyquinoline

International Nuclear Information System (INIS)

Goedemans, W.T.

1981-01-01

There are disclosed aqueous, radioassaying solutions of a chelate of radioactive indium and an 8-hydroxyquinoline, having an essential absence of an organic solvent, e.g., alcohol or chloroform. The solutions are useful in radioassaying warmblooded animals. (author)

New biodegradable organic-soluble chelating agents for simultaneous removal of heavy metals and organic pollutants from contaminated media

International Nuclear Information System (INIS)

Ullmann, Amos; Brauner, Neima; Vazana, Shlomi; Katz, Zhanna; Goikhman, Roman; Seemann, Boaz; Marom, Hanit; Gozin, Michael

2013-01-01

Highlights: • New soil remediation process using phase transition of partially miscible solvents. • Design and synthesis of new bio-degradable, organic soluble chelating agents. • Feasibility tests of the process on authentically polluted sediments and sludge. • Simultaneous removal of toxic metals and organic pollutants was demonstrated. -- Abstract: Advanced biodegradable and non-toxic organic chelators, which are soluble in organic media, were synthesized on the basis of the S,S-ethylenediamine-disuccinate (S,S-EDDS) ligand. The modifications suggested in this work include attachment of a lipophilic hydrocarbon chain (“tail”) to one or both nitrogen atoms of the S,S-EDDS. The new ligands were designed and evaluated for application in the Sediments Remediation Phase Transition Extraction (SR-PTE) process. This novel process is being developed for the simultaneous removal of both heavy metals and organic pollutants from contaminated soils, sediments or sludge. The new chelators were designed to bind various target metal ions, to promote extraction of these ions into organic solvents. Several variations of attached tails were synthesized and tested. The results for one of them, N,N′-bis-dodecyl-S,S-EDDS (C24-EDDS), showed that the metal-ligand complexes are concentrated in the organic-rich phase in the Phase Transition Extraction process (more than 80%). Preliminary applications of the SR-PTE process with the C24-EDDS ligand were conducted also on actually contaminated sludge (field samples). The extraction of five toxic metals, namely, Cd, Cu, Ni, Pb and Zn was examined. In general, the extraction performance of the new ligand was not less than that of S,S-EDDS when a sufficient ligand-to-extracted ion ratio (about 4:1 was applied

New biodegradable organic-soluble chelating agents for simultaneous removal of heavy metals and organic pollutants from contaminated media

Energy Technology Data Exchange (ETDEWEB)

Ullmann, Amos, E-mail: Ullmann@eng.tau.ac.il [Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Brauner, Neima; Vazana, Shlomi; Katz, Zhanna [Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Goikhman, Roman [The Hebrew University of Jerusalem, The Robert H. Smith, Faculty of Agriculture, Food and Environment, Rehovot (Israel); Seemann, Boaz; Marom, Hanit [School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Gozin, Michael, E-mail: cogozin@gmail.com [School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)

2013-09-15

Highlights: • New soil remediation process using phase transition of partially miscible solvents. • Design and synthesis of new bio-degradable, organic soluble chelating agents. • Feasibility tests of the process on authentically polluted sediments and sludge. • Simultaneous removal of toxic metals and organic pollutants was demonstrated. -- Abstract: Advanced biodegradable and non-toxic organic chelators, which are soluble in organic media, were synthesized on the basis of the S,S-ethylenediamine-disuccinate (S,S-EDDS) ligand. The modifications suggested in this work include attachment of a lipophilic hydrocarbon chain (“tail”) to one or both nitrogen atoms of the S,S-EDDS. The new ligands were designed and evaluated for application in the Sediments Remediation Phase Transition Extraction (SR-PTE) process. This novel process is being developed for the simultaneous removal of both heavy metals and organic pollutants from contaminated soils, sediments or sludge. The new chelators were designed to bind various target metal ions, to promote extraction of these ions into organic solvents. Several variations of attached tails were synthesized and tested. The results for one of them, N,N′-bis-dodecyl-S,S-EDDS (C24-EDDS), showed that the metal-ligand complexes are concentrated in the organic-rich phase in the Phase Transition Extraction process (more than 80%). Preliminary applications of the SR-PTE process with the C24-EDDS ligand were conducted also on actually contaminated sludge (field samples). The extraction of five toxic metals, namely, Cd, Cu, Ni, Pb and Zn was examined. In general, the extraction performance of the new ligand was not less than that of S,S-EDDS when a sufficient ligand-to-extracted ion ratio (about 4:1 was applied.

Concentration of sulfur-containing amino acids at turkey broilers during and after muscle dystrophy, fed with deficient feed supplemented with oxidised fat

Directory of Open Access Journals (Sweden)

K. Stoyanchev

2017-06-01

Full Text Available Abstract. The aim of the present study was to reproduce experimentally muscular dystrophy in 50 broiler turkeys, through early nutrition with a diet deficient in vitamin E, selenium and sulfur-containing amino acids, supplemented with oxidised fat and to study blood plasma sulfur containing amino acids (methionine rd and cysteine. The experiments were conducted with 1 day-old broiler turkeys. By the 3 day of life, they were divided into 40 experimental (II group and 10 control birds (I group; the latter were fed a standard compound feed, whereas the former group received a diet deficient in sulfur-containing amino acids methionine and cysteine (reduced up to 50%, vitamin E, and Se (from 0.2 mg/kg in standard feed to 0.01 mg/kg, further supplemented with oxidized fat containing peroxides and aldehydes with peroxide number of the food 8.0 meq O /kg. The clinical signs of experimental muscle dystrophy in broiler turkeys 2 th appeared first by the 25 day of feeding, when the mild clinical form (II A group and the severe clinical form (II B group werewas established. The results indicated clearly that in turkey broilers suffering from muscle dystrophy, the concentrations of sulfur-containing amino acids cysteine and methionine decreased. After the treatment of turkey broilers withmuscle dystrophy, and supplementation with non-deficient forage with Se, vitamin E, but also with sulfurcontaining amino acids cysteine ormethionine with Seled at a dosage 0.06mg/kg, the plasma levels of sulfur-containing amino acids cysteine andmethionine ® was normalized in the mild clinical form (II A group. The birds affected by the severe clinical form of disease (II B group, which were not treated with Seled and whose deficient feed was not corrected, could not recover and levels of sulfur-containing amino acids cysteine and methionine did not normalize.

Selective chelation-supercritical fluid extraction of metal ions from waste materials

International Nuclear Information System (INIS)

Wai, C.N.; Laintz, K.E.; Yonker, C.R.

1993-01-01

The removal of toxic organics, metals, and radioisotopes from solids or liquids is a major concern in the treatment of industrial and nuclear wastes. For this reason, developing methods for selective separation of toxic metals and radioactive materials from solutions of complex matrix is an important problem in environmental research. Recent developments indicate supercritical fluids are good solvents for organic compounds. Many gases become supercritical fluids under moderate temperatures and pressures. For example, the critical temperature and pressure of carbon dioxide are 31 degrees C and 73 atm, respectively. The high diffusivity, low viscosity, and T-P dependence of solvent strength are some attractive properties of supercritical fluid extraction (SFE). Since CO 2 offers the additional benefits of stability and non-toxicity, the SFE technique avoids generation of organic liquid waste and exposure of personnel to toxic solvents. While direct extraction of metal ions by supercritical fluids is highly inefficient, these ions when complexed with organic ligands become quite soluble in supercritical fluids. Specific ligands can be used to achieve selective extraction of metal ions in this process. After SFE, the fluid phase can be depressurized for precipitation of the metal chelates and recycled. The ligand can also be regenerated for repeated use. The success of this selective chelation-supercritical fluid extraction (SC-SFE) process depends on a number of factors including the efficiencies of the selective chelating agents, solubilities of metal chelates in supercritical fluids, rate of extraction, ease of regeneration of the ligands, etc. In this report, the authors present recent results on the studies of the solubilities of metal chelates in supercritical CO 2 , experimental ions from aqueous solution, and the development of selective chelating agents (ionizable crown ethers) for the extraction of lanthanides and actinides

Sulfur- and nitrogen-containing phenol-formaldehyde co-resites for probing the thermal behaviour of heteroatomic forms in solid fuels

Energy Technology Data Exchange (ETDEWEB)

Ismail, K.; Sirkecioglu, O.; Andresen, J.M.; Brown, S.D.; Hall, P.J.; Snape, C.E. [University of Strathclyde, Glasgow (United Kingdom). Dept. of Pure and Applied Chemistry

1996-09-01

In order to probe the formation of sulfur- and nitrogen-containing gases during the pyrolysis and combustion of coals and other solid fuels, non-softening model substrates are required. In this respect phenol-formaldehyde (PF) resins are ideal since they readily facilitate the incorporation of individual heteroatomic functions into a highly crosslinked matrix. A series of sulfur- and nitrogen-containing co-resites were prepared using phenol with, as the second component, thiophene, dibenzothiophene, diphenylsulfide, benzyl phenyl sulfide, thioanisole, 8-hydroxyquinoline and 2-hydroxycarbazole. A mole ratio of 3:1 (phenol: heteroatom-containing component) was used. Resoles containing diphenyldisulfide were also prepared but, due to the comparable bond strengths of the S-S and C-O linkages, a curing temperature of only 130{degree}C was used to avoid cleavage of the disulfide bond. The virtually complete elimination of ether and methylol functions from the resoles by curing at 200{degree}C was monitored by solid-state {sup 13}C nuclear magnetic resonance spectroscopy. The resultant resites were also characterized by sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy, X-ray photoelectron spectroscopy and differential scanning calorimetry. Simple air oxidation was found to selectively convert the aliphatic-bound sulfur to a mixture of sulfones and sulfoxides. Applications of the resites in fuel science are described.

Specific ability of sulfur-ligands on removal of 203Hg-labeled organomercury from hemoglobin in comparison with nitrogen-ligands

International Nuclear Information System (INIS)

Hojo, Yasuji; Sugiura, Yukio; Tanaka, Hisashi

1975-01-01

Removal of 203 Hg-labeled organomercurials, bound to sulfhydryl groups of hemoglobin, by various chelating agents was investigated by the use of equilibrium dialysis. Organomercurials employed were chlormerodrin, methylmercury, ethylmercury and phenylmercury compounds. Higher and more specific effects of the sulfur-ligands, such as penicillamine and glutathione, on removal of organomercurial were found as compared with those of the nitrogen-ligands such as EDTA, glycine and polymethylenediamines. Linear correlation was observed between the degree of organomercury elimination from hemoglobin and the stability constant (log K 1 ) of 1:1 organomercury complex in both the sulfur- and nitrogen-ligand systems and at the same value of log K 1 , the elimination-effect of sulfur-ligands was extremely greater than that of the nitrogen-ligands. The relationship between the average percentage of removal and the Taft's polar substituent constant of organic moiety of the metal was also linear among the organomercury compounds other than chlormerodrin. The average removal percentage by sulfur-ligands increased in the order, ethylmercury>methylmercury>phenylmercury, while that of the nitrogen-ligands was not different among the organomercurials investigated. In addition, direct ligand-exchange reaction between hemoglobin-SH and the ligand coordinating-atom (S or N) against organomercurials rather than Ssub(N2) reaction via the ternary complex, hemoglobin-S-RHg-ligand, is postulated. (auth.)

In vitro and in vivo evaluation of potential aluminum chelators.

Science.gov (United States)

Graff, L; Muller, G; Burnel, D

1995-10-01

The potential for aluminium (Al) chelation by different compounds was determined using 2 in vitro techniques. The formation of stable complexes with Al in an aqueous solution was evaluated using pulse polarography. This technique allowed the influence of temperature and calcium (Ca) to be studied for each compound. Certain compounds (EDDHA, HAES, citric acid and HBED) showed great chelation in the absence of Ca2+ at a temperature of 37 +/- 1 C. An ultrafiltration technique combined with Al determination by atomic emission spectroscopy allowed the efficiency of different substances to complex Al that were previously bound to serum proteins to be estimated. The kinetics of chelation and minimum efficient concentration have been determined for all products studied. EDDHA had chelation potential similar to DFO. The real efficacies of the compounds were studied in vivo to compare the effectiveness of repeated administrations of the best chelating agents (EDDHA, DFO, HAES and tartaric acid) on the distribution and excretion of Al after repeated i.p. administrations to rats. Intraperitoneal EDDHA significantly increased urinary metal (Al, Ca, Cu, Fe and Zn) excretion. These excretions may be correlated to a renal toxic potential property.

Chelates for Micronutrient Nutrition among Crops

Indian Academy of Sciences (India)

years, it has been recognised that compounds containing che- lated metals could .... when using small amounts and no build up of harmful levels. ... degradation of iron chelates. .... down by soil microorganisms into much smaller units for ab-.

Optimization of isolation of cellulose from orange peel using sodium hydroxide and chelating agents.

Science.gov (United States)

Bicu, Ioan; Mustata, Fanica

2013-10-15

Response surface methodology was used to optimize cellulose recovery from orange peel using sodium hydroxide (NaOH) as isolation reagent, and to minimize its ash content using ethylenediaminetetraacetic acid (EDTA) as chelating agent. The independent variables were NaOH charge, EDTA charge and cooking time. Other two constant parameters were cooking temperature (98 °C) and liquid-to-solid ratio (7.5). The dependent variables were cellulose yield and ash content. A second-order polynomial model was used for plotting response surfaces and for determining optimum cooking conditions. The analysis of coefficient values for independent variables in the regression equation showed that NaOH and EDTA charges were major factors influencing the cellulose yield and ash content, respectively. Optimum conditions were defined by: NaOH charge 38.2%, EDTA charge 9.56%, and cooking time 317 min. The predicted cellulose yield was 24.06% and ash content 0.69%. A good agreement between the experimental values and the predicted was observed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Chiral DOTA chelators as an improved platform for biomedical imaging and therapy applications.

Science.gov (United States)

Dai, Lixiong; Jones, Chloe M; Chan, Wesley Ting Kwok; Pham, Tiffany A; Ling, Xiaoxi; Gale, Eric M; Rotile, Nicholas J; Tai, William Chi-Shing; Anderson, Carolyn J; Caravan, Peter; Law, Ga-Lai

2018-02-27

Despite established clinical utilisation, there is an increasing need for safer, more inert gadolinium-based contrast agents, and for chelators that react rapidly with radiometals. Here we report the syntheses of a series of chiral DOTA chelators and their corresponding metal complexes and reveal properties that transcend the parent DOTA compound. We incorporated symmetrical chiral substituents around the tetraaza ring, imparting enhanced rigidity to the DOTA cavity, enabling control over the range of stereoisomers of the lanthanide complexes. The Gd chiral DOTA complexes are shown to be orders of magnitude more inert to Gd release than [GdDOTA] - . These compounds also exhibit very-fast water exchange rates in an optimal range for high field imaging. Radiolabeling studies with (Cu-64/Lu-177) also demonstrate faster labelling properties. These chiral DOTA chelators are alternative general platforms for the development of stable, high relaxivity contrast agents, and for radiometal complexes used for imaging and/or therapy.

Effect of iron and chromium on the graphitization behaviour of sulfur-containing carbon

International Nuclear Information System (INIS)

Tyumentsev, V.A.; Belenkov, E.A.; Saunina, S.I.; Podkopaev, S.A.; Shvejkin, G.P.

1998-01-01

Process of transition of carbonaceous material, containing structurally incorporated sulfur, into graphite and impact of iron and chromium additions are studied. It is established that carbonaceous material, containing more than 1.5 mass % S and also 1.5 mass % Cr 2 O 3 is heterogeneous after thermal treatment at 1300-1600 deg C. It consists of large and sufficiency complete areas of coherent scattering having graphite structure and ultra-dispersed matrix. The number of graphite crystals formed in the presence of dispersed iron within this temperature range, decreases by two times [ru

Method of distillation of sulfurous bituminous shales

Energy Technology Data Exchange (ETDEWEB)

Hallback, A J.S.; Bergh, S V

1918-04-22

A method of distillation of sulfur-containing bituminous shales is characterized by passing the hot sulfur-containing and oil-containing gases and vapors formed during the distillation through burned shale containing iron oxide, so that when these gases and vapors are thereafter cooled they will be, as far as possible, free from sulfur compounds. The patent contains six more claims.

Tooth bleaching using peroxide-containing agents: current status of safety issues.

Science.gov (United States)

Li, Y

1998-08-01

During the last 10 years, at-home tooth bleaching using peroxide-containing agents has quickly become well accepted. It is one of the most popular cosmetic dental procedures for whitening teeth. Although there are few disputes regarding their efficacy, concerns and debates have continued regarding the safety of peroxide-containing tooth bleaching agents. Potential carcinogenicity and genotoxicity of the peroxides used in bleaching agents are the two most persistent and controversial issues. This article reviews and discusses available information on carcinogenicity and genotoxicity of hydrogen peroxide and the potential risks associated with the use of peroxide-containing bleaching agents. Clinical studies reported after the 1996 international symposium on responses of oral tissues to peroxide-containing bleaching agents are also reviewed. Overall evidence supports the conclusion that the proper use of peroxide-containing at-home tooth bleaching agents is safe. However, potential adverse effects may occur in inappropriate applications, abuses, or the use of inappropriate products. At-home tooth bleaching should be monitored by dental professionals to maximize the benefits while minimizing potential risks.

Metal chelate process to remove pollutants from fluids

Science.gov (United States)

Chang, S.G.T.

1994-12-06

The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO[sub x] and optionally SO[sub 2] from a fluid using a metal ion (Fe[sup 2+]) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution. 26 figures.

3,4,5-trihydroxybenzoic acid as chelating agent

International Nuclear Information System (INIS)

Agrawal, M.D.; Bhandari, C.S.; Dixit, M.K.; Sogani, N.C.

1976-01-01

Stability constants of praseodymium chelates of 3,4,5-trihydroxy sodium benzoate are determined by using Bjerrum-Calvin pH titration techniques at constant ionic strength 0.1M-sodium perchlorate and at 28+-0.1 0 C. Values calculated by different methods are in good agreement. The study reveals that during complexation only one proton of the ligand molecule is replaced by the metal and oxygen of adjacent phenolic group acts as a coordinating atom. IR and NMR spectral studies of the ligand reveal that one of the OH groups (in meta position to carboxylic group) remains free while two other phenolic groups are involved in intramolecular hydrogen bonding. One water molecule is found attached in crystalline gallic acid. (author)

Effect of Surface Modification by Chelating Agents on Fischer- Tropsch Performance of Co/SiO{sub 2} Catalysts

Energy Technology Data Exchange (ETDEWEB)

Bambal, Ashish S.; Kugler, Edwin L.; Gardner, Todd H.; Dadyburjor, Dady B.

2013-11-14

The silica support of a Co-based catalyst for Fischer-Tropsch (FT) synthesis was modified by the chelating agents (CAs) nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA). After the modification, characterization of the fresh and spent catalysts show reduced crystallite sizes, a better-dispersed Co₃O₄ phase on the calcined samples, and increased metal dispersions for the reduced samples. The CA-modified catalysts display higher CO conversions, product yields, reaction rates and rate constants. The improved FT performance of CA-modified catalysts is attributed to the formation of stable complexes with Co. The superior performance of the EDTA-modified catalyst in comparison to the NTA-modified catalyst is due to the higher affinity of the former for complex formation with Co ions.

Adsorption equilibrium of uranium from seawater on chelating resin containing amide oxime group

International Nuclear Information System (INIS)

Hori, Takahiro; Saito, Kyoichi; Furusaki, Shintaro; Sugo, Takanobu; Okamoto, Jiro.

1987-01-01

Chelating resins containing amide oxime group were synthesized by radiation-induced graft polymerization. The amount of the amide oxime groups was controlled below about 0.1 mol per kg of base polymer. The adsorption equilibrium of uranium from seawater on this resin was investigated. It was suggested that two neighboring amide oxime groups on the grafted chain captured one uranyl ion, and that single amide oxime ligand had little capacity for the adsorption of uranium. The adsorption equilibrium was correlated by a Langmuir-type equation. The content of neighboring amide oxime groups was 0.406 x 10 -3 mol per kg of base polymer, which corresponded to 0.39 % of the total amount of amide oxime groups. The apparent stoichiometric stability constant for the complex of uranyl ion with the neighboring amide oxime groups in seawater was calculated to be 10 -21.7 . (author)

The N-terminal domain of human DNA helicase Rtel1 contains a redox active iron-sulfur cluster.

Science.gov (United States)

Landry, Aaron P; Ding, Huangen

2014-01-01

Human telomere length regulator Rtel1 is a superfamily II DNA helicase and is essential for maintaining proper length of telomeres in chromosomes. Here we report that the N-terminal domain of human Rtel1 (RtelN) expressed in Escherichia coli cells produces a protein that contains a redox active iron-sulfur cluster with the redox midpoint potential of -248 ± 10 mV (pH 8.0). The iron-sulfur cluster in RtelN is sensitive to hydrogen peroxide and nitric oxide, indicating that reactive oxygen/nitrogen species may modulate the DNA helicase activity of Rtel1 via modification of its iron-sulfur cluster. Purified RtelN retains a weak binding affinity for the single-stranded (ss) and double-stranded (ds) DNA in vitro. However, modification of the iron-sulfur cluster by hydrogen peroxide or nitric oxide does not significantly affect the DNA binding activity of RtelN, suggesting that the iron-sulfur cluster is not directly involved in the DNA interaction in the N-terminal domain of Rtel1.

The N-Terminal Domain of Human DNA Helicase Rtel1 Contains a Redox Active Iron-Sulfur Cluster

Directory of Open Access Journals (Sweden)

Aaron P. Landry

2014-01-01

Full Text Available Human telomere length regulator Rtel1 is a superfamily II DNA helicase and is essential for maintaining proper length of telomeres in chromosomes. Here we report that the N-terminal domain of human Rtel1 (RtelN expressed in Escherichia coli cells produces a protein that contains a redox active iron-sulfur cluster with the redox midpoint potential of −248 ± 10 mV (pH 8.0. The iron-sulfur cluster in RtelN is sensitive to hydrogen peroxide and nitric oxide, indicating that reactive oxygen/nitrogen species may modulate the DNA helicase activity of Rtel1 via modification of its iron-sulfur cluster. Purified RtelN retains a weak binding affinity for the single-stranded (ss and double-stranded (ds DNA in vitro. However, modification of the iron-sulfur cluster by hydrogen peroxide or nitric oxide does not significantly affect the DNA binding activity of RtelN, suggesting that the iron-sulfur cluster is not directly involved in the DNA interaction in the N-terminal domain of Rtel1.

Associations among hair loss, oral sulfur-containing gases, and gastrointestinal and metabolic linked diseases in Japanese elderly men: pilot study

Directory of Open Access Journals (Sweden)

Hamasaki Tomoko

2009-03-01

Full Text Available Abstract Background Male pattern baldness (MPB, an observable trait, has been reported to be associated with various diseases, such as prostate cancer and cardiovascular disease. Oral sulfur-containing gases have also been suggested to be useful as markers of systemic health condition. However, there are no known reports regarding the associations among MPB, and oral sulfur-containing gases, and systemic health conditions in males. Methods We studied 170 male subjects aged either 60 or 65 years old. The degree of MPB was assessed using the Norwood-Hamilton Baldness scale. Oral sulfur-containing gases were measured using a compact-designed device. All subjects completed physical and laboratory blood examinations, a face-to-face medical questionnaire, and an oral examination. Results There were significant differences between the levels of CH3SCH3 and baldness patterns, independent of age. When we analyzed whether the association was linked to systemic health condition, a strong significant association was observed between the level of CH3SCH3 and severe MPB in subjects with gastrointestinal diseases, hypertension, and hypercholesterolemia. Conclusion These results suggest that MPB is associated with the level of CH3SCH3, a sulfur-containing gas that causes oral malodor, in elderly Japanese males. Further, the association was intensified by the existence of gastrointestinal tract and metabolic disorders.

Sulfur-Kβ /sub emission studies on sulfur-bearing heterocycles

International Nuclear Information System (INIS)

Phillips, D.R.; Andermann, G.G.; Fujiwara, F.

1986-01-01

Sulfur-K/β /sub x-ray fluorescence spectroscopy (XFS) has been used to study the electronic structure and bonding in sulfur-bearing heterocycles. XFS not only has the capability of experimentally measuring valence electron energies in molecular species, but can also provide intensity data which can help define the nature of the molecular orbitals defined by the electrons. This report discusses the feasibility of using XFS as an analytical tool for the determination of total and specific sulfur heterocycle content in samples. A variety of compounds were studied. These include thiophene, thiophene derivatives, tetranydrothiophene, several more complex saturated and unsaturated sulfur heterocycles, and heterocycles containing both sulfur and nitrogen. The sulfur-K/β /sub spectra were obtained using a double crystal spectrometer which provided an instrumental resolution of about 0.7 eV

Harmful impact on presynaptic glutamate and GABA transport by carbon dots synthesized from sulfur-containing carbohydrate precursor.

Science.gov (United States)

Borisova, Tatiana; Dekaliuk, Mariia; Pozdnyakova, Natalia; Pastukhov, Artem; Dudarenko, Marina; Borysov, Arsenii; Vari, Sandor G; Demchenko, Alexander P

2017-07-01

Carbon nanoparticles that may be potent air pollutants with adverse effects on human health often contain heteroatoms including sulfur. In order to study in detail their effects on different physiological and biochemical processes, artificially produced carbon dots (CDs) with well-controlled composition that allows fluorescence detection may be of great use. Having been prepared from different types of organic precursors, CDs expose different atoms at their surface suggesting a broad variation of functional groups. Recently, we demonstrated neurotoxic properties of CDs synthesized from the amino acid β-alanine, and it is of importance to analyze whether CDs obtained from different precursors and particularly those exposing sulfur atoms induce similar neurotoxic effects. This study focused on synthesis of CDs from the sulfur-containing precursor thiourea-CDs (TU-CDs) with a size less than 10 nm, their characterization, and neuroactivity assessment. Neuroactive properties of TU-CDs were analyzed based on their effects on the key characteristics of glutamatergic and γ-aminobutyric acid (GABA) neurotransmission in isolated rat brain nerve terminals. It was observed that TU-CDs (0.5-1.0 mg/ml) attenuated the initial velocity of Na + -dependent transporter-mediated uptake and accumulation of L-[ 14 C]glutamate and [ 3 H]GABA by nerve terminals in a dose-dependent manner and increased the ambient level of the neurotransmitters. Starting from the concentration of 0.2 mg/ml, TU-CDs evoked a gradual dose-dependent depolarization of the plasma membrane of nerve terminals measured with the cationic potentiometric dye rhodamine 6G. Within the concentration range of 0.1-0.5 mg/ml, TU-CDs caused an "unphysiological" step-like increase in fluorescence intensity of the рН-sensitive fluorescent dye acridine orange accumulated by synaptic vesicles. Therefore, despite different surface properties and fluorescent features of CDs prepared from different starting materials

Interaction between synthetic lecithin and various sulfur-containing radioprotectors

International Nuclear Information System (INIS)

Rix-Montel, M.A.; Kranck, H.; Vasilescu, D.

1981-01-01

Interaction of the synthetic lecithin dipalmitoylphosphatidylcholine (DPPC) smectic mesophases with sulfur-containing radioprotectors was investigated by means of spectrophotometric and dielectric measurements. Electrical conductivity behavior indicated in all cases that an electrostatic interaction occurs between DPPC and the antiradiation drugs. This interaction is very strong in the case of the WR 2721 molecule. Thermal transitions of DPPC studied by spectrophotometry and conductivity Arrhenius diagrams showed that although the radio-protectors investigated (except WR 2721) delete the pretransition of the lipid phase, the principal transition is not modified. The observed electrostatic interactions are discussed with regard to ionized sites of the phosphatidylcholine lipid head and those of the radioprotectors. The special cases of WR 2721 and its metabolite, WR 1065, are examined

Thermally induced degradation of sulfur-containing aliphatic glucosinolates in broccoli sprouts (Brassica oleracea var. italica) and model systems.

Science.gov (United States)

Hanschen, Franziska S; Platz, Stefanie; Mewis, Inga; Schreiner, Monika; Rohn, Sascha; Kroh, Lothar W

2012-03-07

Processing reduces the glucosinolate (GSL) content of plant food, among other aspects due to thermally induced degradation. Since there is little information about the thermal stability of GSL and formation of corresponding breakdown products, the thermally induced degradation of sulfur-containing aliphatic GSL was studied in broccoli sprouts and with isolated GSL in dry medium at different temperatures as well as in aqueous medium at different pH values. Desulfo-GSL have been analyzed with HPLC-DAD, while breakdown products were estimated using GC-FID. Whereas in the broccoli sprouts structural differences of the GSL with regard to thermal stability exist, the various isolated sulfur-containing aliphatic GSL degraded nearly equally and were in general more stable. In broccoli sprouts, methylsulfanylalkyl GSL were more susceptible to degradation at high temperatures, whereas methylsulfinylalkyl GSL were revealed to be more affected in aqueous medium under alkaline conditions. Besides small amounts of isothiocyanates, the main thermally induced breakdown products of sulfur-containing aliphatic GSL were nitriles. Although they were most rapidly formed at comparatively high temperatures under dry heat conditions, their highest concentrations were found after cooking in acidic medium, conditions being typical for domestic processing.

Coupling fast water exchange to slow molecular tumbling in Gd3+ chelates: why faster is not always better.

Science.gov (United States)

Avedano, Stefano; Botta, Mauro; Haigh, Julian S; Longo, Dario L; Woods, Mark

2013-08-05

The influence of dynamics on solution state structure is a widely overlooked consideration in chemistry. Variations in Gd(3+) chelate hydration with changing coordination geometry and dissociative water exchange kinetics substantially impact the effectiveness (or relaxivity) of monohydrated Gd(3+) chelates as T1-shortening contrast agents for MRI. Theory shows that relaxivity is highly dependent upon the Gd(3+)-water proton distance (rGdH), and yet this distance is almost never considered as a variable in assessing the relaxivity of a Gd(3+) chelate as a potential contrast agent. The consequence of this omission can be seen when considering the relaxivity of isomeric Gd(3+) chelates that exhibit different dissociative water exchange kinetics. The results described herein show that the relaxivity of a chelate with "optimal" dissociative water exchange kinetics is actually lower than that of an isomeric chelate with "suboptimal" dissociative water exchange. When the rate of molecular tumbling of these chelates is slowed, an approach that has long been understood to increase relaxivity, the observed difference in relaxivity is increased with the more rapidly exchanging ("optimal") chelate exhibiting lower relaxivity than the "suboptimally" exchanging isomer. The difference between the chelates arises from a non-field-dependent parameter: either the hydration number (q) or rGdH. For solution state Gd(3+) chelates, changes in the values of q and rGdH are indistinguishable. These parametric expressions simply describe the hydration state of the chelate--i.e., the number and position of closely associating water molecules. The hydration state (q/rGdH(6)) of a chelate is intrinsically linked to its dissociative water exchange rate kex, and the interrelation of these parameters must be considered when examining the relaxivity of Gd(3+) chelates. The data presented herein indicate that the changes in the hydration parameter (q/rGdH(6)) associated with changing dissociative

Combinational chelation therapy abrogates lead-induced neurodegeneration in rats

International Nuclear Information System (INIS)

Pachauri, Vidhu; Saxena, Geetu; Mehta, Ashish; Mishra, Deepshikha; Flora, Swaran J.S.

2009-01-01

Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril + DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

Polyaminoquinoline iron chelators for vectorization of antiproliferative agents: design, synthesis, and validation.

Science.gov (United States)

Corcé, Vincent; Morin, Emmanuelle; Guihéneuf, Solène; Renault, Eric; Renaud, Stéphanie; Cannie, Isabelle; Tripier, Raphaël; Lima, Luís M P; Julienne, Karine; Gouin, Sébastien G; Loréal, Olivier; Deniaud, David; Gaboriau, François

2012-09-19

Iron chelation in tumoral cells has been reported as potentially useful during antitumoral treatment. Our aim was to develop new polyaminoquinoline iron chelators targeting tumoral cells. For this purpose, we designed, synthesized, and evaluated the biological activity of a new generation of iron chelators, which we named Quilamines, based on an 8-hydroxyquinoline (8-HQ) scaffold linked to linear polyamine vectors. These were designed to target tumor cells expressing an overactive polyamine transport system (PTS). A set of Quilamines bearing variable polyamine chains was designed and assessed for their ability to interact with iron. Quilamines were also screened for their cytostatic/cytotoxic effects and their selective uptake by the PTS in the CHO cell line. Our results show that both the 8-HQ moiety and the polyamine part participate in the iron coordination. HQ1-44, the most promising Quilamine identified, presents a homospermidine moiety and was shown to be highly taken up by the PTS and to display an efficient antiproliferative activity that occurred in the micromolar range. In addition, cytotoxicity was only observed at concentrations higher than 100 μM. We also demonstrated the high complexation capacity of HQ1-44 with iron while much weaker complexes were formed with other cations, indicative of a high selectivity. We applied the density functional theory to study the binding energy and the electronic structure of prototypical iron(III)-Quilamine complexes. On the basis of these calculations, Quilamine HQ1-44 is a strong tridentate ligand for iron(III) especially in the form of a 1:2 complex.

Structural analysis and taste evaluation of γ-glutamyl peptides comprising sulfur-containing amino acids.

Science.gov (United States)

Amino, Yusuke; Wakabayashi, Hidehiko; Akashi, Satoko; Ishiwatari, Yutaka

2018-03-01

The structures, flavor-modifying effects, and CaSR activities of γ-glutamyl peptides comprising sulfur-containing amino acids were investigated. The chemical structures, including the linkage mode of the N-terminal glutamic acid, of γ-L-glutamyl-S-(2-propenyl)-L-cysteine (γ-L-glutamyl-S-allyl-L-cysteine) and its sulfoxide isolated from garlic were established by comparing their NMR spectra with those of authentic peptides prepared using chemical methods. Mass spectrometric analysis also enabled determination of the linkage modes in the glutamyl dipeptides by their characteristic fragmentation. In sensory evaluation, these peptides exhibited flavor-modifying effects (continuity) in umami solutions less pronounced but similar to that of glutathione. Furthermore, the peptides exhibited intrinsic flavor due to the sulfur-containing structure, which may be partially responsible for their flavor-modifying effects. In CaSR assays, γ-L-glutamyl-S-methyl-L-cysteinylglycine was most active, which indicates that the presence of a medium-sized aliphatic substituent at the second amino acid residue in γ-glutamyl peptides enhances CaSR activity.

Solubilidade, fracionamento e fitoextração de metais pesados após aplicação de agentes quelantes Solubility, phytoextraction and fractionation of heavy metals as a function of chelating agents applied to soil

Directory of Open Access Journals (Sweden)

Évio Eduardo Chaves de Melo

2006-12-01

Full Text Available A baixa biodegrabilidade de quelantes sintéticos usados para induzir a fitoextração resulta em alto risco ambiental pela possibilidade de lixiviação de metais pesados. Agentes quelantes naturais, mais rapidamente degradados no solo, podem ser uma alternativa para os quelantes sintéticos. O objetivo deste trabalho foi comparar a performance de ácidos orgânicos naturais (gálico, cítrico e oxálico com ácidos sintéticos (EDTA, DTPA e NTA na fitoextração induzida de metais. O solo foi contaminado com 500, 300 e 200 mg kg-1 de Pb, Zn e Cu, respectivamente, e cultivado com milho (Zea mays e mucuna preta (Stizolobium aterrimum. Os agentes quelantes, na dose de 10 mmol kg-1, foram aplicados no solo sete dias antes da coleta das plantas. Amostras do solo foram submetidas à extração com CaCl2 e fracionamento. Os teores dos metais na solução do solo foram também determinados. Os quelantes sintéticos EDTA, DTPA e NTA foram eficientes na solubilização dos metais pesados no solo. Dentre os ácidos orgânicos naturais, apenas o ácido cítrico foi eficiente na solubilização dos metais nas primeiras vinte e quatro horas após a sua aplicação. A distribuição dos metais entre as frações apresentou a seguinte ordem: Pb: matéria orgânica (MO > óxido de Fe amorfo (OxFeA > trocável (Tr > óxido de Fe cristalino (OxFeC; Cu: MO > Tr > OxFeC > OxFeA; e Zn: MO > Tr > OxFeC > OxFeA. De modo geral, a adição dos quelantes sintéticos provocou aumento nos teores trocáveis de Pb e Cu e redução nos teores de Pb, Cu e Zn nas frações óxidos de Fe amorfo e cristalino. O extrator CaCl2 0,01 mol L-1 pode ser utilizado para predição da concentração de Pb, Cu e Zn na solução do solo.The low biodegradability of synthetic chelating agents used for phytoextraction poses a great environmental risk due to the potential for metal leaching. Natural chelating agents can be an alternative to synthetic chelates due to their rapid biodegrability

F-Element ion chelation in highly basic media. Annual progress report, October 1, 1996 - July 1, 1997

International Nuclear Information System (INIS)

Paine, R.T.

1997-01-01

'The specific fundamental chemical objectives of this project are to: (1) study the chemical speciation of Sr and Ln ions in basic media formed in aqueous solutions with and without classical chelation agents (e.g., EDTA, polyphosphates, and organic carboxylates); (2) prepare pyridine N-oxide phosphonate and phosphonoacetate chelators of the types 1--3 and characterize their ionization properties by titrimetric techniques; (3) study the interactions of 5--7 with soluble oxide-hydroxide metallate species and higher molecular weight sols, gels and precipitates containing Sr and Ln ions, as time permits, interactions with oxide-hydroxide metallates of U, Th, Ba, Al and Fe will also be studied; (4) study the interactions of newly designed phosphonate ligands with oxide-hydroxide metallate species; (5) transfer the fundamental coordination chemistry revealed here to research groups at LANL and PNNL that will utilize the results to improve tank waste treatment protocols.'

Synthesis and photocatalytic application of TiO{sub 2} nanoparticles immobilized on polyacrylonitrile nanofibers using EDTA chelating agents

Energy Technology Data Exchange (ETDEWEB)

Chaúque, Eutilério F.C., E-mail: efchauque@gmail.com [Department of Applied Chemistry, University of Johannesburg, Doornfontein, 2028, Johannesburg (South Africa); Adelodun, Adedeji A., E-mail: aadelodun@uj.ac.za [Department of Applied Chemistry, University of Johannesburg, Doornfontein, 2028, Johannesburg (South Africa); Dlamini, Langelihle N., E-mail: lndlamini@uj.ac.za [Department of Applied Chemistry, University of Johannesburg, Doornfontein, 2028, Johannesburg (South Africa); Greyling, Corinne J., E-mail: GreylingC@cput.ac.za [Technology Station in Clothing and Textiles, Cape Peninsula University of Technology, Symphony Way, Belville, 7535 (South Africa); Ray, Sekhar C., E-mail: raysc@unisa.ac.za [Department of Physics, University of South Africa, Florida, 1710, Johannesburg (South Africa); Ngila, J. Catherine, E-mail: jcngila@uj.ac.za [Department of Applied Chemistry, University of Johannesburg, Doornfontein, 2028, Johannesburg (South Africa)

2017-05-01

The photocatalytic properties of TiO{sub 2} nanoparticles (TNPs) have been widely demonstrated in the literature. Here, we report the chemical attachment of TNPs to the surface of polyacrylonitrile nanofibers (PNFs) using the ethylenediaminetetraacetic acid (EDTA) and ethylenediamine (EDA) as the chelating agents. The composite nanofibers were prepared through the chelation of Ti{sup 4+} ions with surface carboxylic and amine groups followed by self-growth of TiO{sub 2} nanoparticles on the surface of modified PNFs during the incubation process. The fabricated composite nanofibers were stabilized at 240 °C in a tube furnace under N{sub 2} gas. The heat treatment served to simultaneously crystallize the TNPs and enhance robustness of PNFs as cyclization reactions and the cross-linking of adjacent nitrile groups (–C=N−C=N–) usually takes place at temperatures above 200 °C. Characterization techniques included X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman spectroscopy and Brunauer-Emmett-Teller (BET) technique. The chemical impregnation of EDTA-EDA on the surface of PNFs resulted in slight increase in the average nanofiber's diameter. The anatase TiO{sub 2} nanoparticles with average 9.4 nm particle size prepared in situ were immobilized on the surface of pre-functionalized PNFs. The fabricated composite nanofibers were applied in the photocatalytic degradation of methyl orange (MO) in synthetic aqueous solutions. The as-prepared composite nanofibers were reused for five (5) cycles without considerable decline in the MO removal efficiency (i.e. >98% of initial performance). - Highlights: • Electrospun polyacrylonitrile nanofibers (PNFs) were chemically modified with EDTA. • The TiO{sub 2}-EDTA-EDA-PNFs composites were prepared through chelation of Ti{sup 4+} ions. • Composites were calcined for simultaneous crystallization and chemical stability. • Ti

[Oxidation of sulfur-containing substrates by aboriginal and experimentally designed microbial communities].

Science.gov (United States)

Pivovarova, T A; Bulaev, A G; Roshchupko, P V; Belyĭ, A V; Kondrat'eva, T F

2012-01-01

Aboriginal and experimental (constructed of pure microbial cultures) communities of acidophilic chemolithotrophs have been studied. The oxidation of elemental sulfur, sodium thiosulfate, and potassium tetrathionate as sole sources of energy has been monitored. The oxidation rate of the experimental community is higher as compared to the aboriginal community isolated from a flotation concentrate of pyrrhotine-containing pyrite-arsenopyrite gold-arsenic sulfide ore. The degree of oxidation of the mentioned S substrates amounts to 17.91, 68.30, and 93.94% for the experimental microbial community and to 10.71, 56.03, and 79.50% for the aboriginal community, respectively. The degree of oxidation of sulfur sulfide forms in the ore flotation concentrate is 59.15% by the aboriginal microbial community and 49.40% by the experimental microbial community. Despite a higher rate of oxidation of S substrates as a sole source of energy by the experimental microbial community, the aboriginal community oxidizes S substrates at a higher rate in the flotation concentrate of pyrrhotine-containing pyrite-arsenopyrite gold-arsenic sulfide ore, from which it was isolated. Bacterial-chemical oxidation of the flotation concentrate by the aboriginal microbial community allows for the extraction of an additional 32.3% of gold from sulfide minerals, which is by 5.7% larger compared to the yield obtained by the experimental microbial community.

IRON CHELATION THERAPY IN THALASSEMIA SYNDROMES

Directory of Open Access Journals (Sweden)

Paolo Cianciulli

2009-06-01

Full Text Available Transfusional hemosiderosis is a frequent complication in patients with transfusion dependent chronic diseases such as  thalassemias and severe type of sickle cell diseases. As there are no physiological mechanisms to excrete the iron contained in transfused red cells (1 unit of blood contains approximately 200 mg of iron the excess of iron is stored in various organs. Cardiomyopathy is the most severe complication covering more than 70% of the causes of death of thalassemic patients. Although the current reference standard iron chelator deferoxamine (DFO has been used clinically for over four decades, its effectiveness is limited by a demanding therapeutic regimen that leads to poor compliance. Despite poor compliance, because of the inconvenience of subcutaneous infusion, DFO improved considerably the survival and quality of life of patients with thalassemia. Deferiprone since 1998 and Deferasirox since 2005 were licensed for clinical use. The oral chelators have a better compliance because of oral use, a comparable efficacy to DFO in iron excretion and probably a better penetration to myocardial cells. Considerable increase in iron excretion was documented with combination therapy of DFO and Deferiprone. The proper use of the three chelators will improve the prevention and treatment of iron overload, it will reduce  complications, and improve survival and quality of life of transfused patients

[Decorporation agents for internal radioactive contamination].

Science.gov (United States)

Ohmachi, Yasushi

2015-01-01

When radionuclides are accidentally ingested or inhaled, blood circulation or tissue/organ deposition of the radionuclides causes systemic or local radiation effects. In such cases, decorporation therapy is used to reduce the health risks due to their intake. Decorporation therapy includes reduction and/or inhibition of absorption from the gastrointestinal tract, isotopic dilution, and the use of diuretics, adsorbents, and chelating agents. For example, penicillamine is recommended as a chelating agent for copper contamination, and diethylene triamine pentaacetic acid is approved for the treatment of internal contamination with plutonium. During chelation therapy, the removal effect of the drugs should be monitored using a whole-body counter and/or bioassay. Some authorities, such as the National Council on Radiation Protection and Measurements and International Atomic Energy Agency, have reported recommended decorporation agents for each radionuclide. However, few drugs are approved by the US Food and Drug Administration, and many are off-label-use agents. Because many decontamination agents are drugs that have been available for a long time and have limited efficacy, the development of new, higher-efficacy drugs has been carried out mainly in the USA and France. In this article, in addition to an outline of decorporation agents for internal radioactive contamination, an outline of our research on decorporation agents for actinide (uranium and plutonium) contamination and for radio-cesium contamination is also presented.

Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

Science.gov (United States)

Fan, Liren; Song, Jiqing; Bai, Wenbo; Wang, Shengping; Zeng, Ming; Li, Xiaoming; Zhou, Yang; Li, Haifeng; Lu, Haiwei

2016-02-01

A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shell Fe3O4@SiO2 (FS) nanoparticles. These reactions used a silane coupling agent and sodium chloroacetate. The results show that FS@IDA could chelate the heavy metal component of Cd, Zn, Pb, Cu and Ni carbonates, lead sulfate and lead chloride in water-insoluble salt systems. The resulting FS@IDA-Cd and FS@IDA-Pb chelates could be magnetically separated, resulting in removal rates of approximately 84.9% and 72.2% for Cd and Pb, respectively. FS@IDA could not remove the residual heavy metals and those bound to organic matter in the soil. FS@IDA did not significantly alter the chemical composition of the soil, and it allowed for fast chelating capture, simple magnetic separation and facilitated heavy metal elution. FS@IDA could also be easily prepared and reprocessed.

Induction of Cellulase by Gentiobiose and Its Sulfur-Containing Analog in Penicillium purpurogenum

OpenAIRE

Kurasawa, Takashi; Yachi, Makoto; Suto, Manabu; Kamagata, Yoichi; Takao, Shoichi; Tomita, Fusao

1992-01-01

Cellulase induction by β-glucodisaccharides was investigated by using non-cellulase-induced mycelia of Penicillium purpurogenum P-26, a highly-cellulase-producing fungus. Gentiobiose induced significant amounts of cellulase compared with cellobiose when nojirimycin was added to the induction medium to inhibit extracellular β-glucosidase activity. Thiogentiobiose (6-S-β-d-glucopyranosyl-6-thio-d-glucose), a sulfur-containing analog of gentiobiose, was more effective for cellulase induction tha...

The Effect of Extinguishing Agents on Burning Sonobuoys Containing Lithium-Sulfur Dioxide Batteries

Science.gov (United States)

1989-09-01

components and the JP-5. In addition, the types of extinguish- ment materials, such as carbor spheres, that have some degree of success on metal fires , would...NWC TP 6571, publication UNCLASSIFIED.) 8. John F. Riley. "Na-X, a New Fire Extinguishing Agent for Metal Fires ," Fire Technology, Vol. 10, No. 4

Characterizing the biotransformation of sulfur-containing wastes in simulated landfill reactors.

Science.gov (United States)

Sun, Wenjie; Sun, Mei; Barlaz, Morton A

2016-07-01

Landfills that accept municipal solid waste (MSW) in the U.S. may also accept a number of sulfur-containing wastes including residues from coal or MSW combustion, and construction and demolition (C&D) waste. Under anaerobic conditions that dominate landfills, microbially mediated processes can convert sulfate to hydrogen sulfide (H2S). The presence of H2S in landfill gas is problematic for several reasons including its low odor threshold, human toxicity, and corrosive nature. The objective of this study was to develop and demonstrate a laboratory-scale reactor method to measure the H2S production potential of a range of sulfur-containing wastes. The H2S production potential was measured in 8-L reactors that were filled with a mixture of the target waste, newsprint as a source of organic carbon required for microbial sulfate reduction, and leachate from decomposed residential MSW as an inoculum. Reactors were operated with and without N2 sparging through the reactors, which was designed to reduce H2S accumulation and toxicity. Both H2S and CH4 yields were consistently higher in reactors that were sparged with N2 although the magnitude of the effect varied. The laboratory-measured first order decay rate constants for H2S and CH4 production were used to estimate constants that were applicable in landfills. The estimated constants ranged from 0.11yr(-1) for C&D fines to 0.38yr(-1) for a mixed fly ash and bottom ash from MSW combustion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Immersion autometallography: histochemical in situ capturing of zinc ions in catalytic zinc-sulfur nanocrystals.

Science.gov (United States)

Danscher, Gorm; Stoltenberg, Meredin; Bruhn, Mikkel; Søndergaard, Chris; Jensen, Dorete

2004-12-01

In the mid-1980s, two versions of Timm's original immersion sulfide silver method were published. The authors used immersion of tissue in a sulfide solution as opposed to Timm, who used immersion of tissue blocks in hydrogen sulfide-bubbled alcohol. The autometallography staining resulting from the "sulfide only immersion" was not particularly impressive, but the significance of this return to an old approach became obvious when Wenzel and co-workers presented their approach in connection with introduction by the Palmiter group of zinc transporter 3 (ZnT3). The Wenzel/Palmiter pictures are the first high-resolution, high-quality pictures taken from tissues in which free and loosely bound zinc ions have been captured in zinc-sulfur nanocrystals by immersion. The trick was to place formalin-fixed blocks of mouse brains in a solution containing 3% glutaraldehyde and 0.1% sodium sulfide, ingredients used for transcardial perfusion in the zinc-specific NeoTimm method. That the NeoTimm technique results in silver enhancement of zinc-sulfur nanocrystals has been proved by proton-induced X-ray multielement analyses (PIXE) and in vivo chelation with diethyldithiocarbamate (DEDTC). The aims of the present study were (a) to make the immersion-based capturing of zinc ions in zinc-sulfur nanocrystals work directly on sections and slices of fixed brain tissue, (b) to work out protocols that ensure zinc specificity and optimal quality of the staining, (c) to apply "immersion autometallography" (iZnSAMG) to other tissues that contain zinc-enriched (ZEN) cells, and (d) to make the immersion approach work on unfixed fresh tissue.

Combinatorial synthesis by nature: volatile organic sulfur-containing constituents of Ruta chalepensis L.

Science.gov (United States)

Escher, Sina; Niclass, Yvan; van de Waal, Matthijs; Starkenmann, Christian

2006-09-01

Ongoing interest in discovering new natural fragrance and flavor ingredients prompted us to examine a solvent extract of sulfurous-sweaty smelling Ruta chalepensis L. (Rutaceae) plant material more closely. Twenty-one sulfur-containing constituents of similar structures were identified by GC/MS techniques. Amongst them, 14 have never been described to occur in nature. The compounds 1-18 belong to a family of natural flavor and fragrance molecules having a 1,3-positioned O,S moiety in common. The identities of the natural constituents were confirmed by comparison with synthetic reference samples, and the organoleptic properties of the latter were studied. The relative and absolute configurations of the four stereoisomers of 4-methyl-3-sulfanylhexan-1-ol (5) were established by stereoselective synthesis. The natural isomers consisted of a 65 : 35 mixture of (3R,4S)-5 and (3S,4S)-5.

Prebiotics mitigate in vitro sulfur-containing odour generation in caecal content of pigs

Directory of Open Access Journals (Sweden)

Yuan Fan Deng

2015-03-01

Full Text Available The objective of this study was to examine the effects and role of prebiotics, such as inulin, fructo-oligosaccharides (FOS and galactooligosaccharides (GAS, to mitigate sulfur-containing odour gases, hydrogen sulfide (H2S and methyl mercaptan (CH3SH using pigs as in vitro study model. Inocula obtained from pigs were incubated at 39°C for 24 h using 550 mg sterilised substrate (caecal contents supplemented with or without 50 mg prebiotics. Production of total gas, H2S and CH3SH were determined. The results showed that total gas production for the caecal content of pigs was 57.3 mL, and that for H2S and CH3SH was 220.2 and 15.2 μL, respectively. The total gas production increased (P<0.05, whereas concentrations of H2S and CH3SH decreased (P<0.05 with supplementation of prebiotics. Among the prebiotics, inulin was the most effective in mitigating H2S and CH3SH productions, reducing the two malodorous gases by 14.7 and 19.8%, respectively. The reduction of the above two sulfur- containing gases was supported by lower sulfate-reducing bacteria population and higher sulfate radical concentrations in the prebiotics, particularly that of inulin supplementation group.

Bioinspired Interfacial Chelating-like Reinforcement Strategy toward Mechanically Enhanced Lamellar Materials.

Science.gov (United States)

Chen, Ke; Zhang, Shuhao; Li, Anran; Tang, Xuke; Li, Lidong; Guo, Lin

2018-05-22

Many biological organisms usually derived from the ordered assembly of heterogeneous, hierarchical inorganic/organic constituents exhibit outstanding mechanical integration, but have proven to be difficult to produce the combination of excellent mechanical properties, such as strength, toughness, and light weight, by merely mimicking their component and structural characteristics. Herein, inspired by biologically strong chelating interactions of phytic acid (PA) or IP6 in many biomaterials, we present a biologically interfacial chelating-like reinforcement (BICR) strategy for fabrication of a highly dense ordered "brick-and-mortar" microstructure by incorporating tiny amounts of a natural chelating agent ( e. g., PA) into the interface or the interlamination of a material ( e. g., graphene oxide (GO)), which shows joint improvement in hardness (∼41.0%), strength (∼124.1%), maximum Young's modulus (∼134.7%), and toughness (∼118.5%) in the natural environment. Besides, for different composite matrix systems and artificial chelating agents, the BICR strategy has been proven successful for greatly enhancing their mechanical properties, which is superior to many previous reinforcing approaches. This point can be mainly attributed to the stronger noncovalent cross-linking interactions such as dense hydrogen bonds between the richer phosphate (hydroxyl) groups on its cyclohexanehexol ring and active sites of GO, giving rise to the larger energy dissipation at its hybrid interfaces. It is also simple and environmentally friendly for further scale-up fabrication and can be readily extended to other material systems, which opens an advanced reinforcement route to construct structural materials with high mechanical performance in an efficient way for practical applications.

Antibacterial and antibiofilm effects of iron chelators against Prevotella intermedia.

Science.gov (United States)

Moon, Ji-Hoi; Kim, Cheul; Lee, Hee-Su; Kim, Sung-Woon; Lee, Jin-Yong

2013-09-01

Prevotella intermedia, a major periodontopathogen, has been shown to be resistant to many antibiotics. In the present study, we examined the effect of the FDA-approved iron chelators deferoxamine (DFO) and deferasirox (DFRA) against planktonic and biofilm cells of P. intermedia in order to evaluate the possibility of using these iron chelators as alternative control agents against P. intermedia. DFRA showed strong antimicrobial activity (MIC and MBC values of 0.16 mg ml(-1)) against planktonic P. intermedia. At subMICs, DFRA partially inhibited the bacterial growth and considerably prolonged the bacterial doubling time. DFO was unable to completely inhibit the bacterial growth in the concentration range tested and was not bactericidal. Crystal violet binding assay for the assessment of biofilm formation by P. intermedia showed that DFRA significantly decreased the biofilm-forming activity as well as the biofilm formation, while DFO was less effective. DFRA was chosen for further study. In the ATP-bioluminescent assay, which reflects viable cell counts, subMICs of DFRA significantly decreased the bioactivity of biofilms in a concentration-dependent manner. Under the scanning electron microscope, P. intermedia cells in DFRA-treated biofilm were significantly elongated compared to those in untreated biofilm. Further experiments are necessary to show that iron chelators may be used as a therapeutic agent for periodontal disease.

Mixed ligand chelate therapy for plutonium and toxic metals from energy power production. Final report, April 15, 1977-October 14, 1980

International Nuclear Information System (INIS)

Schubert, J.

1980-01-01

The results of experiments are summarized on the ability of combinations of chelating agents to modify the genotoxicity or tissue distributions. The mutagenicities of Cr and of chelating agents were determined. The metals described in the report are Pu(IV), Cd(II), Cr(III), and Cr(VI). Accurate measurements were made of the ability of CaNa 2 EDTA, CaNa 3 DTPA, and DMPS to reduce mortality in mice given doses (i.p.) of CdCl 2 well above the 100% lethal level. The efficacy in terms of the mmoles/kg needed to reduce the mortality was: DTPA > EDTA > DMPS. The combination of DTPA + DMPS proved most promising though little evidence for mixed complex formation was noted. Potentiometric titration studies the case of Pu(IV) a few combinations proved effective, but only when given shortly after Pu administration and then only in the liver but not the skeleton. It is recommended that metabolically stable chelating agents be used in combinations, especially for those combinations which may form very stable mixed ligand chelates

Demetalation of Fe, Mn, and Cu chelates and complexes: application to the NMR analysis of micronutrient fertilizers.

Science.gov (United States)

López-Rayo, Sandra; Lucena, Juan J; Laghi, Luca; Cremonini, Mauro A

2011-12-28

The application of nuclear magnetic resonance (NMR) for the quality control of fertilizers based on Fe(3+), Mn(2+), and Cu(2+) chelates and complexes is precluded by the strong paramagnetism of metals. Recently, a method based on the use of ferrocyanide has been described to remove iron from commercial iron chelates based on the o,o-EDDHA [ethylenediamine-N,N'bis(2-hydroxyphenylacetic)acid] chelating agent for their analysis and quantification by NMR. The present work extended that procedure to other paramagnetic ions, manganese and copper, and other chelating, EDTA (ethylenediaminetetraacetic acid), IDHA [N-(1,2-dicarboxyethyl)-d,l-aspartic acid], and complexing agents, gluconate and heptagluconate. Results showed that the removal of the paramagnetic ions was complete, allowing us to obtain (1)H NMR spectra characterized by narrow peaks. The quantification of the ligands by NMR and high-performance liquid chromatography showed that their complete recovery was granted. The NMR analysis enabled detection and quantification of unknown impurities without the need of pure compounds as internal standards.

STUDIES REGARDING THE CHELATE-INDUCED HYPERACCUMULATION OF CU AND FE USING LOLIUM PERENNE SPECIES IN MINING AREAS

Directory of Open Access Journals (Sweden)

ANCA-DIANA PRICOP

2009-05-01

Full Text Available The plant capacity to absorb high amounts of metal for a short period of time is the major factor that influences the efficiency of phytoextraction. The hyperaccumulating plants uptake high amounts in their tissues correlated to the metal concentrations in soil. Chelating agents have the capacity to induce the metal accumulation in biomass. They increase metal bioavailability for plants by releasing the metal in accessible forms. The present study emphasizes that in the case of EDTA use, the obtained biomass is smaller compared to the other variants, showing a lower tolerance to this chelating agent of Lolium perenne species. Cu and Fe phytoextraction by Lolium perenne species is higher in the case of EDTA use. Cu bioaccumulation has higher values in variants with compost-sterile mixture ratio of 1:4 in comparison with Fe. In the case of the best compost-sterile mixture ratio of 1:3 the highest biomass is obtained in all the variants, biosolids’ effect being stronger compared to the chelating agent.

High precision isotopic ratio analysis of volatile metal chelates

International Nuclear Information System (INIS)

Hachey, D.L.; Blais, J.C.; Klein, P.D.

1980-01-01

High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50 Cr, 60 Ni, and 65 Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60 Ni (0.02-2.15 at. % excess) and 62 Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26 Mg and 44 Ca, was analyzed by EI/MS. 1 figure, 5 tables

Copper chelators: chemical properties and bio-medical applications.

Science.gov (United States)

Tegoni, M; Valensin, D; Toso, L; Remelli, M

2014-01-01

Copper is present in different concentrations and chemical forms throughout the earth crust, surface and deep water and even, in trace amounts, in the atmosphere itself. Copper is one of the first metals used by humans, the first artifacts dating back 10,000 years ago. Currently, the world production of refined copper exceeds 16,000 tons/year. Copper is a micro-element essential to life, principally for its red-ox properties that make it a necessary cofactor for many enzymes, like cytochrome-c oxidase and superoxide dismutase. In some animal species (e.g. octopus, snails, spiders, oysters) copper-hemocyanins also act as carriers of oxygen instead of hemoglobin. However, these red-ox properties also make the pair Cu(+)/Cu(2+) a formidable catalyst for the formation of reactive oxygen species, when copper is present in excess in the body or in tissues. The treatment of choice in cases of copper overloading or intoxication is the chelation therapy. Different molecules are already in clinical use as chelators or under study or clinical trial. It is worth noting that chelation therapy has also been suggested to treat some neurodegenerative diseases or cardiovascular disorders. In this review, after a brief description of the homeostasis and some cases of dyshomeostasis of copper, the main (used or potential) chelators are described; their properties in solution, even in relation to the presence of metal or ligand competitors, under physiological conditions, are discussed. The legislation of the most important Western countries, regarding both the use of chelating agents and the limits of copper in foods, drugs and cosmetics, is also outlined.

Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

Energy Technology Data Exchange (ETDEWEB)

Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K. (Abbott Laboratories, Department 90M, Abbott Park, IL (United States))

1991-01-01

Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.

Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

International Nuclear Information System (INIS)

Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K.

1991-01-01

Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates

REVIEW ARTICLE:Future of Lead Chelation – Distribution and Treatment

Directory of Open Access Journals (Sweden)

Venkatesh Thuppil

2012-01-01

Full Text Available Lead is the major environmental toxin resulting in the ill health and deleterious effect on almost all organs in the human body in a slow and effective manner. The best treatment for lead poisoning is chelation therapy which is next only to prevention. The authors describe the disruption of homeostasis of the human body by lead in various tissues like blood, bones, liver, kidneys and brain; and the ability of lead to enter the cell using calcium channels and calcium receptors like Ca++ dependant K+ ion channels, transient receptor potential channels, T-tubules, calmodulin receptors, inositol trisphosphate receptors and ryanodine receptors. We report a few novel chelating agents like ionophores, decadentate ligands, picolinate ligands, octadentate ligand, allicin, thiamine, that show good potential for being used in chelation therapy. Future of leadpoisoning is a challenge to all and it needs to be meticulously studies to have an economic and health approach.

From biomass to fuels: hydrotreating of oxygen-containing feeds on a CoMo/Al{sub 2}O{sub 3} hydrodesulfurization catalyst

Energy Technology Data Exchange (ETDEWEB)

Viljava, T.-R.

2001-07-01

Biomass is a renewable alternative to fossil raw materials in the production of liquid fuels and chemicals. Liquefied biomass contains an abundance of oxygen-containing molecules that need to be removed to improve the stability of the liquids. A hydrotreating process, hydrodeoxygenation (HDO), is used for the purpose. Hydrodeoxygenation is similar to the hydrodesulfurization (HDS) process used in oil refining, relying upon a presulfided CoMo/{gamma}-Al{sub 2}O{sub 2}; catalyst. The stability of the sulfided catalyst is critical in HDO because biocrudes usually do not contain the sulfur compounds needed to maintain the sulfidation of the catalyst. The aim of this work was to examine the role of sulfur in maintaining the activity of the HDO catalyst. Sulfur was introduced as an organic sulfur-containing co-reactant or as a sulfur substituent in an oxygen-containing reactant molecule as a way of simulating mixed feeds composed of biocrudes and conventional crudes, or it was introduced as a low molecular weight sulfiding agent. In addition, the stability of the sulfided catalyst against changes in the feed composition was studied to find out whether the activity of the catalyst could be maintained by carrying out HDO alternately with HDS. Simultaneous HDO and HDS was studied in a batch reactor with model compounds having a sulfur-containing (inercapto or inethylmercapto) and an oxygen-containing (hydroxyl or inethoxy) substituent in the same molecule, and with binary mixtures of mono-substituted benzene compounds. In both cases, the reactions of the oxygencontaining substituents were strongly suppressed as long as a sulfur-containing functionality was present. HDS reactions of inercapto and inethylinercapto groups were either enhanced or retarded in the presence of oxygen-containing functionality. HDS was enhanced when the oxygen-containing substituent was located in Para-position to the sulfur substituent thereby increasing the electronegativity of the sulfur atom and

Sulfur-containing constituents and one 1H-pyrrole-2-carboxylic acid derivative from pineapple [Ananas comosus (L.) Merr.] fruit.

Science.gov (United States)

Zheng, Zong-Ping; Ma, Jinyu; Cheng, Ka-Wing; Chao, Jianfei; Zhu, Qin; Chang, Raymond Chuen-Chung; Zhao, Ming; Lin, Zhi-Xiu; Wang, Mingfu

2010-12-01

Two sulfur-containing compounds, (S)-2-amino-5-((R)-1-carboxy-2-((E)-3-(4-hydroxy-3-methoxyphenyl)allylthio)ethyl-amino)-5-oxopentanoic acid (1) and (S)-2-amino-5-((R)-1-(carboxymethylamino)-3-((E)-3-(4-hydroxyphenyl)allylthio)-1-oxopropan-2-ylamino)-5-oxopentanoic acid (2), and one 1H-pyrrole-2-carboxylic acid derivative, 6-(3-(1H-pyrrole-2-carbonyloxy)-2-hydroxypropoxy)-3,4,5-trihydroxy-tetrahydro-2H-pyran-2-carboxylic acid (3), together with eighteen known phenolic compounds, were isolated from the fruits of pineapple. Their structures were elucidated by a combination of spectroscopic analyses. Some of these compounds showed inhibitory activities against tyrosinase. The half maximal inhibitory concentration values of compounds 1, 4, 5, 6, 7 are lower than 1 mM. These compounds may contribute to the well-known anti-browning effect of pineapple juice and be potential skin whitening agents in cosmetic applications. Copyright © 2010 Elsevier Ltd. All rights reserved.

Chelate chase of radiopharmaceuticals reversibly bound to monoclonal antibodies improves dosimetry

International Nuclear Information System (INIS)

Goodwin, D.A.; Smith, S.I.; Meares, C.F.; David, G.S.; McTigue, M.; Finston, R.A.

1986-01-01

One hundred micrograms of monoclonal antibody (MoAb) CHA 255 with a binding constant Kb of 4 x 10 9 was complexed with indium-111 labeled BLEDTA II, GLEDTA IV, benzyl EDTA, and an EDTA conjugate of Fab. The 24-hour tumor and organ distribution in BALB/c mice bearing KHJJ tumors was studied for each compound alone, the antibody complex, and 3 hours following a chelate chase of the antibody complex. Whole-body biological half-life was measured for 7 days with and without a chelate chase for each antibody complex. The 24-hour whole-body counts dropped 20-60% within 3 hours of administering the chelate chase. Blood concentration fell over 89% within 3 hours of administering the chase and there was a decrease in concentration in all organs, except the kidneys, of 10 to 85%. Theoretical equivalent human doses were calculated from the 24-hour organ concentrations, effective half-life, and MIRD 11 S values (absorbed dose per cumulated activity). Liver and spleen were the target organs, with the dose ranging from 0.50 to 3.91 rads per millicurie. The reduction in organ radiation dose varied up to 95% following the chelate chase. Rapid selective renal clearance of chelate labeled radiopharmaceuticals by competitive inhibition (chelate chase) of their reversible binding to monoclonal antibodies, greatly improves the radiation dosimetry of tumor imaging agents. 28 references, 5 figures, 5 tables

Effects of iron(III)chelates on the solubility of heavy metals in calcareous soils

Energy Technology Data Exchange (ETDEWEB)

Ylivainio, Kari, E-mail: kari.ylivainio@mtt.f [Department of Applied Chemistry and Microbiology, FIN-00014 University of Helsinki (Finland)

2010-10-15

In this study I evaluated the effects of complexing agents on the solubility of heavy metals in an incubation experiment up to 56 days when complexing agents were applied as Fe-chelates (Fe-EDDS(S,S), Fe-EDDS(mix), Fe-EDTA and Fe-EDDHA) on calcareous soils at a level sufficient to correct Fe chlorosis (0.1 mmol kg{sup -1}). Of these ligands, EDDHA was the most efficient in keeping Fe in water-soluble form, and EDDS increased the solubility of Cu and Zn most, and only EDTA increased the solubility of Cd and Pb. EDTA increased the solubility of Ni steadily during the incubation period, equalling about 5-8% of the added EDTA concentration. [S,S]-EDDS was biodegraded within 56 days, whereas EDDS(mix) was less biodegradable. Ni-chelates were the most recalcitrant against biodegradation. The study shows that even a moderate input of chelates to soil increases the solubility of toxic heavy metals and their risk of leaching. - When correcting Fe chlorosis Fe-EDDS causes lower environmental concern than Fe-EDTA.

Effects of iron(III)chelates on the solubility of heavy metals in calcareous soils

International Nuclear Information System (INIS)

Ylivainio, Kari

2010-01-01

In this study I evaluated the effects of complexing agents on the solubility of heavy metals in an incubation experiment up to 56 days when complexing agents were applied as Fe-chelates (Fe-EDDS(S,S), Fe-EDDS(mix), Fe-EDTA and Fe-EDDHA) on calcareous soils at a level sufficient to correct Fe chlorosis (0.1 mmol kg -1 ). Of these ligands, EDDHA was the most efficient in keeping Fe in water-soluble form, and EDDS increased the solubility of Cu and Zn most, and only EDTA increased the solubility of Cd and Pb. EDTA increased the solubility of Ni steadily during the incubation period, equalling about 5-8% of the added EDTA concentration. [S,S]-EDDS was biodegraded within 56 days, whereas EDDS(mix) was less biodegradable. Ni-chelates were the most recalcitrant against biodegradation. The study shows that even a moderate input of chelates to soil increases the solubility of toxic heavy metals and their risk of leaching. - When correcting Fe chlorosis Fe-EDDS causes lower environmental concern than Fe-EDTA.

Effects of iron(III)chelates on the solubility of heavy metals in calcareous soils.

Science.gov (United States)

Ylivainio, Kari

2010-10-01

In this study I evaluated the effects of complexing agents on the solubility of heavy metals in an incubation experiment up to 56 days when complexing agents were applied as Fe-chelates (Fe-EDDS(S,S), Fe-EDDS(mix), Fe-EDTA and Fe-EDDHA) on calcareous soils at a level sufficient to correct Fe chlorosis (0.1 mmol kg(-1)). Of these ligands, EDDHA was the most efficient in keeping Fe in water-soluble form, and EDDS increased the solubility of Cu and Zn most, and only EDTA increased the solubility of Cd and Pb. EDTA increased the solubility of Ni steadily during the incubation period, equalling about 5-8% of the added EDTA concentration. [S,S]-EDDS was biodegraded within 56 days, whereas EDDS(mix) was less biodegradable. Ni-chelates were the most recalcitrant against biodegradation. The study shows that even a moderate input of chelates to soil increases the solubility of toxic heavy metals and their risk of leaching. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Sulfur removal from low-sulfur gasoline and diesel fuel by metal-organic frameworks

Energy Technology Data Exchange (ETDEWEB)

Hagen, G.; Haemmerle, M.; Moos, R. [Functional Materials, University of Bayreuth, Bayreuth (Germany); Malkowsky, I.M.; Kiener, C. [BASF SE, Ludwigshafen (Germany); Achmann, S.

2010-02-15

Several materials in the class of metal-organic frameworks (MOF) were investigated to determine their sorption characteristics for sulfur compounds from fuels. The materials were tested using different model oils and common fuels such as low-sulfur gasoline or diesel fuel at room temperature and ambient pressure. Thiophene and tetrahydrothiophene (THT) were chosen as model substances. Total-sulfur concentrations in the model oils ranged from 30 mg/kg (S from thiophene) to 9 mg/kg (S from tetrahydrothiophene) as determined by elementary analysis. Initial sulfur contents of 8 mg/kg and 10 mg/kg were identified for low-sulfur gasoline and for diesel fuel, respectively, by analysis of the common liquid fuels. Most of the MOF materials examined were not suitable for use as sulfur adsorbers. However, a high efficiency for sulfur removal from fuels and model oils was noticed for a special copper-containing MOF (copper benzene-1,3,5-tricarboxylate, Cu-BTC-MOF). By use of this material, 78 wt % of the sulfur content was removed from thiophene containing model oils and an even higher decrease of up to 86 wt % was obtained for THT-based model oils. Moreover, the sulfur content of low-sulfur gasoline was reduced to 6.5 mg/kg, which represented a decrease of more than 22 %. The sulfur level in diesel fuel was reduced by an extent of 13 wt %. Time-resolved measurements demonstrated that the sulfur-sorption mainly occurs in the first 60 min after contact with the adsorbent, so that the total time span of the desulfurization process can be limited to 1 h. Therefore, this material seems to be highly suitable for sulfur reduction in commercial fuels in order to meet regulatory requirements and demands for automotive exhaust catalysis-systems or exhaust gas sensors. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Complexation studies of actinides (U, Pu, Am) with linear polyamino-carboxylate ligands and sidero-chelates

International Nuclear Information System (INIS)

Nguyen, L.V.

2010-01-01

As part of our research endeavour aimed at developing and improving decontamination processes of wastewater containing alpha emitters, physico-chemical complexation studies of actinides (U, Pu, Am) with organic open-chain ligands such as poly-aminocarboxylic acids (H 4 EDTA) and sidero-chelates (di-hydroxamic acids and desferrioxamine B) have been carried out. Gaining a clear understanding of the coordination properties of the targeted actinides is an essential step towards the selection of the most appropriate chelating agents that will exhibit high uptake efficiencies. EXAFS (Extended X-ray Absorption Fine Structure) measurements at the ESRF synchrotron enabled to elucidate the coordination scheme of uranium and plutonium complexes. Solution thermodynamic investigations were intended to provide valuable information about the nature and the stability of the uranium(VI) and americium(III) complexes prevailing at a given pH in solution. The set of stability constants determined from potentiometric and UV-visible spectrophotometric titrations, allowed to predict the speciation of the selected actinides in presence of the aforementioned ligands and to determine the pH range required for achieving 'ultimate' decontamination. (author) [fr

Chelating polymeric membranes

KAUST Repository

Peinemann, Klaus-Viktor; Villalobos Vazquez de la Parra, Luis Francisco; Hilke, Roland

2015-01-01

microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

Extracellular gadolinium contrast agents: Differences in stability

International Nuclear Information System (INIS)

Morcos, S.K.

2008-01-01

Extracellular gadolinium contrast agents (Gd-CA) are either linear or macrocyclic chelates available as ionic or non-ionic preparations. The molecular structure whether cyclic or linear and ionicity determines the stability of Gd-CA. Linear chelates are flexible open chains which do not offer a strong binding to Gd 3+ . In contrast, the macrocyclic chelates offer a strong binding to Gd 3+ by the virtue of being preorganized rigid rings of almost optimal size to cage the gadolinium atom. Non-ionic preparations are also less stable in comparison to the ionic ones as the binding between Gd 3+ with the negatively charged carboxyl groups is stronger in comparison to that with amides or alcohol in the non-ionic preparations. According to stability constants and kinetic measurements, the most stable Gd-CM is the ionic-macrocyclic chelate Gd-DOTA and the least stable agents are the non-ionic linear chelates gadodiamide and gadoversetamide. In vivo data confirmed the low stability of non-ionic linear chelates but no significant difference was observed amongst the macrocyclic agents whether ionic (Gd-DOTA) or non-ionic such as Gd-HP-DO3A and Gd-BT-DO3A. The stability of Gd-CA seems to be an important factor in the pathogenesis of the serious complication of nephrogenic systemic fibrosis. Gd-CA of low stability are likely to undergo transmetallation and release free Gd ions that deposit in tissue and attract circulating fibrocytes to initiate the process of fibrosis. No cases of NSF have been observed so far after the exclusive use of the stable macrocyclic Gd-CA

Determination of Ultra-trace Rhodium in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Cloud Point Extraction Using 2-(5-Iodo-2-Pyridylazo)-5-Dimethylaminoaniline as a Chelating Agent.

Science.gov (United States)

Han, Quan; Huo, Yanyan; Wu, Jiangyan; He, Yaping; Yang, Xiaohui; Yang, Longhu

2017-03-24

A highly sensitive method based on cloud point extraction (CPE) separation/preconcentration and graphite furnace atomic absorption spectrometry (GFAAS) detection has been developed for the determination of ultra-trace amounts of rhodium in water samples. A new reagent, 2-(5-iodo-2-pyridylazo)-5-dimethylaminoaniline (5-I-PADMA), was used as the chelating agent and the nonionic surfactant TritonX-114 was chosen as extractant. In a HAc-NaAc buffer solution at pH 5.5, Rh(III) reacts with 5-I-PADMA to form a stable chelate by heating in a boiling water bath for 10 min. Subsequently, the chelate is extracted into the surfactant phase and separated from bulk water. The factors affecting CPE were investigated. Under the optimized conditions, the calibration graph was linear in the range of 0.1-6.0 ng/mL, the detection limit was 0.023 ng/mL for rhodium and relative standard deviation was 3.67% ( c = 1.0 ng/mL, n = 11)．The method has been applied to the determination of trace rhodium in water samples with satisfactory results.

Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract

Science.gov (United States)

DeAlba-Montero, I.; Morales-Sánchez, Elpidio; Araujo-Martínez, Rene

2017-01-01

This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used. PMID:28286459

Comparative studies on sulfur, peroxide, and radiation vulcanization of EFDM rubber

International Nuclear Information System (INIS)

Abdel-Aziz, M.M.; Basfar, A.A.; Mofti, S.

2000-01-01

The temperature and concentration dependence of the vulcanization characteristics and mechanical properties of epdm rubber containing various concentrations of peroxide compounds was studied. The peroxides used are Luperox Di, Luperox 500-40 Ke, peroximon Dc Sc and peroximon Dc 40 Ke. The optimum cure parameters for the different types of peroxides indicated that Luperox Di, relatively, Give the best properties among the studied peroxides. The mechanical properties of EPDM containing different concentrations of Luperox Di and vulcanized at different temperatures were compared with those of either radiation or sulfur-cured EPDM. The modulus stress and tensile strength of the Luperox Di-cured EPDM were found to increase with either increasing the temperature of vulcanization and/ or concentration of the peroxide. Moreover, the tensile strength values are much higher than those of the sulfur-cured samples, except for those with low concentration of peroxide and vulcanized at relatively low temperature. A comparable result to those of the chemically vulcanized samples was attained by the radiation- vulcanized samples containing 1 phr of crosslinking agent and irradiated to 150 KGy

Sequestering agents for the removal of actinides from waste streams

Energy Technology Data Exchange (ETDEWEB)

Raymond, K.N.; White, D.J.; Xu, Jide; Mohs, T.R. [Univ. of California, Berkeley, CA (United States)

1997-10-01

The goal of this project is to take a biomimetic approach toward developing new separation technologies for the removal of radioactive elements from contaminated DOE sites. To achieve this objective, the authors are investigating the fundamental chemistry of naturally occurring, highly specific metal ion sequestering agents and developing them into liquid/liquid and solid supported actinide extraction agents. Nature produces sideophores (e.g., Enterobactin and Desferrioxamine B) to selectivity sequester Lewis acidic metal ions, in particular Fe(III), from its surroundings. These chelating agents typically use multiple catechols or hydroxamic acids to form polydentate ligands that chelate the metal ion forming very stable complexes. The authors are investigating and developing analogous molecules into selective chelators targeting actinide(IV) ions, which display similar properties to Fe(III). By taking advantage of differences in charge, preferred coordination number, and pH stability range, the transition from nature to actinide sequestering agents has been applied to the development of new and highly selective actinide extraction technologies. Additionally, the authors have shown that these chelating ligands are versatile ligands for chelating U(VI). In particular, they have been studying their coordination chemistry and fundamental interactions with the uranyl ion [UO{sub 2}]{sup 2+}, the dominant form of uranium found in aqueous media. With an understanding of this chemistry, and results obtained from in vivo uranium sequestration studies, it should be possible to apply these actinide(IV) extraction technologies to the development of new extraction agents for the removal of uranium from waste streams.

method and container for production of diagnostic scanning agents

International Nuclear Information System (INIS)

Ruddock, C.F.

1979-01-01

The pertechnetate ion containing the technetium-99m isotope has limited applications in diagnostic scanning because it does not readily form complexes with materials which locate in specific parts of the body. Stannous salts have been widely used to reduce the pertechnetate to a form which readily complexes with materials. In the present invention, both a container and a more suitable metal reducing agent are discussed for transforming the technetium in pertechnetate for diagnostic scanning use. The vessel contains tin or a tin-containing alloy as a reducing agent for the pertechnetate and a complexant for the reduced technetium; all contents are sterile and dry. The present invention is advantageous over the stannous salts method since (1) problems of stannous salt instability during production, storage and after labelling are eliminated; (2) production procedures are simplified; (3) it is not essential to nitrogen purge vials before sterilisation; (4) it reduces toxicity; (5) the shelf life of diagnostic scanning kits may be dramatically improved; (6) the metal reducing agent may be sterilised by γ-irradiation without deteriorating; (7) the labelling technique can be performed over a wide pH range; and (8) the technique should be unaffected by technetium-99 in the technetium-99m. (U.K.)

Sulfur polymer cement, a new stabilization agent for mixed and low- level radioactive waste

International Nuclear Information System (INIS)

Darnell, G.R.

1991-01-01

Solidification and stabilization agents for radioactive, hazardous, and mixed wastes are failing to pass governmental tests at alarming rates. The Department of Energy's National Low-Level Waste Management Program funded testing of Sulfur Polymer Cement (SPC) by Brookhaven National Laboratory during the 1980s. Those tests and tests by the US Bureau of Mines (the original developer of SPC), universities, states, and the concrete industry have shown SPC to be superior to hydraulic cements in most cases. Superior in what wastes can be successfully combined and in the quantity of waste that can be combined and still pass the tests established by the US Environmental Protection Agency and the US Nuclear Regulatory Commission

Effects of a diuretic and its combination with chelating agent on the removal of depleted uranium in rats

International Nuclear Information System (INIS)

Ikeda, Mizuyo; Fukuda, Satoshi; Nakamura, Mariko; Yoshida, Hiroki; Yan Xueming; Xie Yuyuan

2008-01-01

We examined the effects of a diuretic, isotonic saline, and chelating agent, catechol-3, 6-bis (methyleimiodiacetic acid) (CBMIDA), on the excretion and prevention of renal damage of depleted uranium (DU). Male Wistar rats (8 weeks old) divided into seven groups were preinjected intraperitoneally with 4 mg/kg DU and then the six groups were injected intraperitoneally with a diuretic, a diuretic plus isotonic saline, 480 mg/kg or 720 mg/kg CBMIDA alone, or 480 mg/kg or 720 mg/kg CBMIDA plus a diuretic and saline for three days, and the one group was as the control (no treatment). The rats were killed 6 days after DU injection. The results indicated that the diuretic alone and the diuretic with isotonic saline were not effective in removing uranium from the body and protecting the renal function, and also did not help to increase significantly the effects of CBMIDA. (author)

Synthesis and chemical characterization of the novel agronomically relevant pentadentate chelate 2-(2-((2-hydroxybenzyl)amino)ethylamino)-2-(2-hydroxyphenyl)acetic acid (DCHA).

Science.gov (United States)

López-Rayo, Sandra; Hernández, Diana; Lucena, Juan J; Escudero, Rosa; Gómez-Gallego, Mar; Sierra, Miguel A

2010-07-14

Iron chelates analogous to o,o-EDDHA/Fe(3+) are the fertilizers chosen to treat iron chlorosis in plants growing on calcareous soil. The isomer o,p-EDDHA/Fe(3+) presents less stability but faster assimilation by the plant than o,o-EDDHA/Fe(3+), because only five coordinating groups are able to complex Fe(3+). The new chelating agent 2-(2-((2-hydroxybenzyl)amino)ethylamino)-2-(2-hydroxyphenyl)acetic acid (DCHA) has been synthesized to obtain an iron fertilizer with intermediate stability between o,o-EDDHA/Fe(3+) and o,p-EDDHA/Fe(3+) and with fast assimilation. Its synthesis has been done starting from phenol, N-acetylethylendiamine, glyoxylic acid, and NaOH in a three-step sequence. The purity of the DCHA chelating agent, its protonation, and Ca(2+), Mg(2+), Fe(3+), and Cu(2+) stability constants, together with its ability to maintain iron in solution in different agronomic conditions, have been determined. The results indicate that the chelate DCHA/Fe(3+) has intermediate stability between those of o,o-EDDHA/Fe(3+) and o,p-EDDHA/Fe(3+) complexes and that it is capable of maintaining the Fe(3+) in agronomic conditions. This new chelating agent may be effective in correcting iron chlorosis in plants.

Profound morphological changes in the erythrocytes and fibrin networks of patients with hemochromatosis or with hyperferritinemia, and their normalization by iron chelators and other agents.

Directory of Open Access Journals (Sweden)

Etheresia Pretorius

Full Text Available It is well-known that individuals with increased iron levels are more prone to thrombotic diseases, mainly due to the presence of unliganded iron, and thereby the increased production of hydroxyl radicals. It is also known that erythrocytes (RBCs may play an important role during thrombotic events. Therefore the purpose of the current study was to assess whether RBCs had an altered morphology in individuals with hereditary hemochromatosis (HH, as well as some who displayed hyperferritinemia (HF. Using scanning electron microscopy, we also assessed means by which the RBC and fibrin morphology might be normalized. An important objective was to test the hypothesis that the altered RBC morphology was due to the presence of excess unliganded iron by removing it through chelation. Very striking differences were observed, in that the erythrocytes from HH and HF individuals were distorted and had a much greater axial ratio compared to that accompanying the discoid appearance seen in the normal samples. The response to thrombin, and the appearance of a platelet-rich plasma smear, were also markedly different. These differences could largely be reversed by the iron chelator desferal and to some degree by the iron chelator clioquinol, or by the free radical trapping agents salicylate or selenite (that may themselves also be iron chelators. These findings are consistent with the view that the aberrant morphology of the HH and HF erythrocytes is caused, at least in part, by unliganded ('free' iron, whether derived directly via raised ferritin levels or otherwise, and that lowering it or affecting the consequences of its action may be of therapeutic benefit. The findings also bear on the question of the extent to which accepting blood donations from HH individuals may be desirable or otherwise.

Adsorption of actinides by chelating agents containing benzene rings, fixed on charcoal

International Nuclear Information System (INIS)

Valentini Ganzerli, M.T.; Crespi Caramella, V.; Maggi, L.

1999-01-01

The focus of this paper is on the analysis of the actinides in the hydrosphere to study their environmental dispersion. The 8-hydroxyquinoline family and the benzohydroxamic acid have a complexing ability towards the actinides, even if in different oxidation states. Taking advantage of this ability, their salts with some organic acids or bases were prepared. In this way compounds were obtained easily incorporated into active charcoal. Only a small amount of the prepared adsorber may be equilibrated with large sample volumes. Subsequently it can be recovered by filtration. The adsorbed ions may be then re-dissolved with a small volume of the appropriate eluting solution. The 8-hydroxy-quinolines and the 8-hydroxyquinoline produced salts with the benzilic acid. These compounds similarly behave and show wide adsorption coefficients for solutions of pH higher than 3. The adsorption takes place by means of the formation of a complex of the actinide ion with the hydroxyquinoline moiety and also with the benzilic anion. Provided that the active extracting agent is not dissolved in a medium but fixed into a solid phase, the whole adsorption process may be regarded as a solvent extraction reaction. The benzohydroxamic acid was treated with the diphenylamine or with the tribenzylamine to obtain salts, later adsorbed into the charcoal. The adsorption of actinide ions seems to take place by means of a precipitation mechanism of the actinide ions with the hydroxamate ions for solution of pH higher than 3.5. Also in this case high values were obtained for the distribution coefficients. The actinide ions act similarly in the +4 or +6 oxidation state towards the prepared adsorber series. Therefore, it is possible to use only one adsorber to concentrate all actinides. Methods of analysis of actinides in the environment may be suitably set up and the concentration step based on these new prepared adsorber may improve the whole procedure. (authors)

Evaluation and improvement of gamma-ray stability of chelating resins containing oxy-acid groups of phosphorus

International Nuclear Information System (INIS)

Jyo, Akinori; Yamabe, Kazunori; Shuto, Taketomi

1998-01-01

Chelating resins containing oxy-acid groups of phosphorus, such as phosphonic and phosphoric acid groups have been studied from the point of view of solvent extraction processes for the separation of nuclear fuel elements as well as of fission product ones. The present work was planned to evaluate the effect of gamma-ray on properties of the resins and to obtain directional information for design of the resins having high stability to gamma-ray. It was clarified that gamma-ray stability of the resins is not high; tolerance limit is ca. 2.3x10 3 C/kg. The present work also clarified that polymers crosslinked with divinylbenzene have much higher gamma-ray stability than ones crosslinked with dimetacrylate esters of oligo (ethylene glycol)s. (J.P.N.)

Genomic Insights into the Sulfur Metabolism of Phototrophic Green Sulfur Bacteria

DEFF Research Database (Denmark)

Frigaard, Niels-Ulrik; Bryant, Donald A.

2008-01-01

Green sulfur bacteria (GSB) utilize various combinations of sulfide, elemental sulfur, thiosulfate, ferrous iron, and hydrogen for anaerobic photoautotrophic growth. Genome sequence data is currently available for 12 strains of GSB. We present here a genome-based survey of the distribution...... and phylogenies of genes involved in oxidation of sulfur compounds in these strains. Sulfide:quinone reductase, encoded by sqr, is the only known sulfur-oxidizing enzyme found in all strains. All sulfide-utilizing strains contain the dissimilatory sulfite reductase dsrABCEFHLNMKJOPT genes, which appear...... to be involved in elemental sulfur utilization. All thiosulfate-utilizing strains have an identical sox gene cluster (soxJXYZAKBW). The soxCD genes found in certain other thiosulfate-utilizing organisms like Paracoccus pantotrophus are absent from GSB. Genes encoding flavocytochrome c (fccAB), adenosine-5...

Mathematical modeling of the effects of aerobic and anaerobic chelate biodegradation on actinide speciation

International Nuclear Information System (INIS)

Banaszak, J.E.; VanBriesen, J.; Rittmann, B.E.; Reed, D.T.

1998-01-01

Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and, hence, the mobility of actinides in subsurface environments. We combined mathematical modeling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bio-utilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modeling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems

Mathematical modelling of the effects of aerobic and anaerobic chelate biodegradation on actinide speciation

International Nuclear Information System (INIS)

Banaszak, J.E.; VanBriesen, J.M.; Rittmann, B.E.; Reed, D.T.

1998-01-01

Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and hence, the mobility of actinides in subsurface environments. We combined mathematical modelling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bioutilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modelling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems. (orig.)

Fabrication and evaluation of tumor-targeted positive MRI contrast agent based on ultrasmall MnO nanoparticles.

Science.gov (United States)

Huang, Haitao; Yue, Tao; Xu, Ke; Golzarian, Jafar; Yu, Jiahui; Huang, Jin

2015-07-01

Gd(III) chelate is currently used as positive magnetic resonance imaging (MRI) contrast agent in clinical diagnosis, but generally induces the risk of nephrogenic systemic fibrosis (NSF) due to the dissociated Gd(3+) from Gd(III) chelates. To develop a novel positive MRI contrast agent with low toxicity and high sensitivity, ultrasmall MnO nanoparticles were PEGylated via catechol-Mn chelation and conjugated with cRGD as active targeting function to tumor. Particularly, the MnO nanoparticles with a size of ca. 5nm were modified by α,β-poly(aspartic acid)-based graft polymer containing PEG and DOPA moieties and, meanwhile, conjugated with cRGD to produce the contrast agent with a size of ca. 100nm and a longitudinal relaxivity (r1) of 10.2mM(-1)S(-1). Such nanoscaled contrast agent integrated passive- and active-targeting function to tumor, and its efficient accumulation behavior in tumor was verified by in vivo distribution study. At the same time, the PEG moiety played a role of hydrophilic coating to improve the biocompatibility and stability under storing and physiological conditions, and especially might guarantee enough circulation time in blood. Moreover, in vivo MRI revealed a good and long-term effect of enhancing MRI signal for as-fabricated contrast agent while cell viability assay proved its acceptable cytotoxicity for MRI application. On the whole, the as-fabricated PEGylated and cRGD-functionalized contrast agent based on ultrasmall MnO nanoparticles showed a great potential to the T1-weighted MRI diagnosis of tumor. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Protection against SR 4233 (tirapazamine) aerobic cytotoxicity by the metal chelators desferrioxamine and tiron

International Nuclear Information System (INIS)

Herscher, L.L.; Krishna, M.C.; Cook, J.A.

1994-01-01

Metal chelating agents and antioxidants were evaluated as potential protectors against aerobic SR 4233 cytotoxicity in Chinese hamster V79 cells. The differential protection of aerobic and hypoxic cells by two metal chelators, desferrrioxamine and Tiron, is discussed in the context of their potential use in the on-going clinical trials with SR 4233. Cytotoxicity was evaluated using clonogenic assay. SR 4233 exposure was done in glass flasks as a function of time either alone or in the presence of the following agents: superoxide dismutase, catalase, 5,5-dimethyl-1-pyrroline, Trolox, ICRF-187, desferrioxamine, Tiron (1,2-dihydroxybenzene-3,5-disulfonate), and ascorbic acid. Experiments done under hypoxic conditions were carried out in specially designed glass flasks that were gassed with humidified nitrogen/carbon dioxide mixture and with a side-arm reservoir from which SR 4233 was added to cell media after hypoxia was obtained. Electron paramagnetic resonance studies were also performed. Electron paramagnetic resonance and spectrophotometry experiments suggest that under aerobic conditions SR 4233 undergoes futile redox cycling to produce superoxide. Treatment of cells during aerobic exposure to SR 4233 with the enzymes superoxide dismutase and catalase, the spin trapping agent DMPO, the water-soluble vitamin E analog Trolox, and the metal chelator ICRF-187 provided little or no protection against aerobic SR 4233 cytotoxicity. However, two other metal chelators, desferrioxamine and Tiron afforded significant protection against minimal protection to hypoxic cells treated with SR 4233. One potential mechanism of aerobic cytotoxicity is redox cycling of SR 4233 with molecular oxygen resulting in several potentially toxic oxidative species that overburden the intrinsic intracellular detoxification systems such as superoxide dismutase, catalase, and glutathione peroxidase. 23 refs., 4 figs., 1 tab

Destruction of chemical agent simulants in a supercritical water oxidation bench-scale reactor

Energy Technology Data Exchange (ETDEWEB)

Veriansyah, Bambang [Supercritical Fluid Research Laboratory, Clean Technology Research Center, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of) and Department of Green Process and System Engineering, University of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)]. E-mail: vaveri@kist.re.kr; Kim, Jae-Duck [Supercritical Fluid Research Laboratory, Clean Technology Research Center, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of) and Department of Green Process and System Engineering, University of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)]. E-mail: jdkim@kist.re.kr; Lee, Jong-Chol [Agency for Defense Development (ADD), P.O. Box 35-1, Yuseong-gu, Daejeon (Korea, Republic of)]. E-mail: jcleeadd@hanafos.com

2007-08-17

A new design of supercritical water oxidation (SCWO) bench-scale reactor has been developed to handle high-risk wastes resulting from munitions demilitarization. The reactor consists of a concentric vertical double wall in which SCWO reaction takes place inside an inner tube (titanium grade 2, non-porous) whereas pressure resistance is ensured by a Hastelloy C-276 external vessel. The performances of this reactor were investigated with two different kinds of chemical warfare agent simulants: OPA (a mixture of isopropyl amine and isopropyl alcohol) as the binary precursor for nerve agent of sarin and thiodiglycol [TDG (HOC{sub 2}H{sub 4}){sub 2}S] as the model organic sulfur heteroatom. High destruction rates based on total organic carbon (TOC) were achieved (>99.99%) without production of chars or undesired gases such as carbon monoxide and methane. The carbon-containing product was carbon dioxide whereas the nitrogen-containing products were nitrogen and nitrous oxide. Sulfur was totally recovered in the aqueous effluent as sulfuric acid. No corrosion was noticed in the reactor after a cumulative operation time of more than 250 h. The titanium tube shielded successfully the pressure vessel from corrosion.

Synthesis of a novel bicyclic bifunctional chelating agent

International Nuclear Information System (INIS)

Sweet, M.P.; Mease, R.C.; Joshi, V.; Srivastava, S.C.

1994-01-01

Semi-rigid ligands such as cyclohexyl EDTA (CDTA) and 4-isothiocyanato-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (4-ICE) form chelates that are more stable in vivo compared to those of EDTA or DTPA. The authors have synthesized a new class of ligands in which the metal-binding polyaminocarboxylate groups are incorporated onto the rigid bicyclo[2.2.2]octane ring system. These ligands are expected to contribute to even higher in vivo stability of radiometal complexes. The synthesis of the first in this series of ligands (2.3-diaminobicyclo[2.2.2]octane-N,N,N',N'-tetraacetic acid, BODTA) began with a Diels-Alder reaction of 1,3-diacetylimidazolin-2-one and 1,3-cyclohexadiene. Base hydrolysis afforded the diamine. Following alkylation of the diamine with ethyl iodoacetate and hydrogenation of the double bond, hydrolysis of the esters gave BODTA. For initial conjugation with proteins, an average of one carboxylic acid of BODTA was converted into an NHS ester. In vivo testing of radioimmunoconjugates, prepared using this method, is in progress

Study on the utilization of a sodium-sulfuric acid solution for the uranium minerals' leaching

International Nuclear Information System (INIS)

Echenique, Patricia; Fruchtenicht, Fernando; Gil, Daniel; Vigo, Daniel; Bouza, Angel; Vert, Gabriela; Becquart, Elena

1988-01-01

Argentine uranium minerals have been leached at bench scale with a different agent trying to reduce sulfuric acid consumption. The leaching agent was a sodium sulfate-sulfuric acid solution and the ore was from Sierra Pintada (San Rafael - Mendoza). The work was performed in stirred vessel at atmospheric pressure. The influence of different variables, pH, temperature, oxidant agent, sodium sulfate concentration and time, in the sulfuric acid consumption and the uranium yield was studied. (Author) [es

Chelating agent-free, vapor-assisted crystallization method to synthesize hierarchical microporous/mesoporous MIL-125 (Ti).

Science.gov (United States)

McNamara, Nicholas D; Hicks, Jason C

2015-03-11

Titanium-based microporous heterogeneous catalysts are widely studied but are often limited by the accessibility of reactants to active sites. Metal-organic frameworks (MOFs), such as MIL-125 (Ti), exhibit enhanced surface areas due to their high intrinsic microporosity, but the pore diameters of most microporous MOFs are often too small to allow for the diffusion of larger reactants (>7 Å) relevant to petroleum and biomass upgrading. In this work, hierarchical microporous MIL-125 exhibiting significantly enhanced interparticle mesoporosity was synthesized using a chelating-free, vapor-assisted crystallization method. The resulting hierarchical MOF was examined as an active catalyst for the oxidation of dibenzothiophene (DBT) with tert-butyl hydroperoxide and outperformed the solely microporous analogue. This was attributed to greater access of the substrate to surface active sites, as the pores in the microporous analogues were of inadequate size to accommodate DBT. Moreover, thiophene adsorption studies suggested the mesoporous MOF contained larger amounts of unsaturated metal sites that could enhance the observed catalytic activity.

Effects of mineral matters on evolution of sulfur-containing gases in pyrolysis and hydropyrolysis

Energy Technology Data Exchange (ETDEWEB)

Chen, H.; Li, B.; Zhang, B. [Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan (China). State Key Lab. of Coal Conversion

1998-07-01

The evolution of sulfur-containing gases were investigated using two Chinese coals with their de-ash and de-pyrite forms in pyrolysis and hydropyrolysis. Mineral matter can not only return H{sub 2}S produced in pyrolysis and hydropyrolysis, but also catalyse hydrodesulfurization and reduce COS formation. Secondary reactions markedly influence COS formation. Mineral matter can reduce CH{sub 3}SH formation, and pyrite shows positive effects on CH{sub 3}SH formation. 7 refs., 6 figs., 1 tab.

Europium(III) chelate-dyed nanoparticles as donors in a homogeneous proximity-based immunoassay for estradiol

International Nuclear Information System (INIS)

Kokko, Leena; Sandberg, Kaisa; Loevgren, Timo; Soukka, Tero

2004-01-01

Nanoparticles containing thousands of fluorescent europium(III) chelates have a very high specific activity compared to traditional lanthanide chelate labels. It can be assumed that if these particles are used in a homogeneous assay as donors, multiple chelates can excite a single acceptor in turns and the energy transfer to the acceptor is increased. The principle was employed in an immunoassay using luminescent resonance energy transfer from a long lifetime europium(III) chelate-dyed nanoparticle to a short lifetime, near-infrared fluorescent molecule. Due to energy transfer fluorescence lifetime of the sensitised emission was prolonged and fluorescence could be measured using a time-resolved detection. A competitive homogeneous immunoassay for estradiol was created using 92 nm europium(III) chelate-dyed nanoparticle coated with 17β-estradiol specific recombinant antibody Fab fragments as a donor and estradiol conjugated with near-infrared dye AlexaFluor 680 as an acceptor. The density of Fab fragments on the surface of the particle influenced the sensitivity of the immunoassay. The optimal Fab density was reached when the entire surface of the particle participated in the energy transfer, but the areas where the energy was transferred to a single acceptor, did not overlap. We were able to detect estradiol concentrations down to 70 pmol l -1 (3xSD of a standard containing 0 nmol l -1 of E2) using a 96-well platform. In this study we demonstrated that nanoparticles containing lanthanide chelates could be used as efficient donors in homogeneous assays

Efficacy of the chelating agent CaEDTA in reversing lead-induced changes in behavior.

Science.gov (United States)

Cory-Slechta, D A; Weiss, B

1989-01-01

The chelating agent CaEDTA has been reported to reverse the deficits in intellectual function and performance associated with Pb (lead) exposure in children. However, such studies have not included rigorous controls for the intervention procedures per se. The experiments reported here examined reversibility of performance changes in a rat model based on behavior sensitive to low-level Pb exposure. Rats were exposed to 50 ppm sodium or Pb acetate in drinking water from weaning. Performance maintained under a Fixed-Interval schedule of food reinforcement began at 55 days of age. Following the onset of the characteristic increase in short interresponse times (IRTs) associated with low-level Pb exposure after 35 experimental sessions, Pb treatment was terminated. Animals within both the control and Pb groups were then matched on the basis of performance indices and injected daily for 5 days with either saline, 75 mg/kg or 150 mg/kg CaEDTA. Subsequent changes in F1 performance were monitored for 35-60 sessions. No consistent effects of CaEDTA were detected in control animals. CaEDTA treatment failed to reverse the behavioral effects in Pb-exposed animals. If anything, it tended to further increase the proportion of short IRTs. These data suggest that better controlled clinical studies are warranted to evaluate the efficacy of CaEDTA in reversing Pb-induced behavioral effects before its application for these purposes becomes widespread.

Characterization of commercial iron chelates and their behavior in an alkaline and calcareous soil.

Science.gov (United States)

Cantera, Rodrigo G; Zamarreño, Angel M; García-Mina, José M

2002-12-18

Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time.

Sulphur-containing Amino Acids: Protective Role Against Free Radicals and Heavy Metals.

Science.gov (United States)

Colovic, Mirjana B; Vasic, Vesna M; Djuric, Dragan M; Krstic, Danijela Z

2018-01-30

Sulphur is an abundant element in biological systems, which plays an important role in processes essential for life as a constituent of proteins, vitamins and other crucial biomolecules. The major source of sulphur for humans is plants being able to use inorganic sulphur in the purpose of sulphur-containing amino acids synthesis. Sulphur-containing amino acids include methionine, cysteine, homocysteine, and taurine. Methionine and cysteine are classified as proteinogenic, canonic amino acids incorporated in protein structure. Sulphur amino acids are involved in the synthesis of intracellular antioxidants such as glutathione and N-acetyl cysteine. Moreover, naturally occurring sulphur-containing ligands are effective and safe detoxifying agents, often used in order to prevent toxic metal ions effects and their accumulation in human body. Literature search for peer-reviewed articles was performed using PubMed and Scopus databases, and utilizing appropriate keywords. This review is focused on sulphur-containing amino acids - methionine, cysteine, taurine, and their derivatives - glutathione and N-acetylcysteine, and their defense effects as antioxidant agents against free radicals. Additionally, the protective effects of sulphur-containing ligands against the toxic effects of heavy and transition metal ions, and their reactivation role towards the enzyme inhibition are described. Sulphur-containing amino acids represent a powerful part of cell antioxidant system. Thus, they are essential in the maintenance of normal cellular functions and health. In addition to their worthy antioxidant action, sulphur-containing amino acids may offer a chelating site for heavy metals. Accordingly, they may be supplemented during chelating therapy, providing beneficial effects in eliminating toxic metals. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Studies on In-situ Chelation/Supercritical Fluid Extraction of Lanthanides and Actinides Using a Radiotracer Technique

International Nuclear Information System (INIS)

Lin, Yuehe; Wu, Hong; Smart, Neil G.; Wai, Chien M.

2001-01-01

Radioisotope tracer techniques were used to study the process of in-situ chelation/supercritical fluid extraction(SFE) of La3+ and Lu3+ from solid matrix using mixed ligand hexafluoroacetylacetone (HFA) and tributylphosphate (TBP) as chelating agents. A lab-built SFE extactor was used in this study and the extractor design was optimized based on the experimental results. Quantitative recovery of La and Lu was achieved when the extrator design was optimized. Extraction of uranium from real world samples was also investigated to demonstrate the capability of this chelation/SFE technology for environmental remediation applications. A novel on-line back extraction technique for the recovery of metal ions and regeneration of ligands is also reported.

Evaluation of the efficacy of chelating agent of catechol amino carboxylic acid for removal of radiothorium

International Nuclear Information System (INIS)

Chen Honghong; Hu Yuxing; Wang Yinghua; Jin Meiying; Luo Meichu; Sun Meizhen

2003-01-01

The efficacy of prompt single and consecutive administration of chelating agent 7601 and 9501 of catechol amino carboxylic acid for the decorporation of 234 Th in rats and mice was investigated. DTPA was used as positive control. The complexing competitive abilities of 7601 and 9501 to mobilize the thorium with bovine serum albumin were studied with gel chromatography in vitro. The inhibition effect of 7601 and 9501 on superoxide anions radicals (O 2 -. ) were measured with electron spin resonance. The results showed that 7601 and 9501 could increase the excretion of 234 Th in urine and faces by 63%-70% and decrease markedly retention of 234 Th in liver and skeleton, which have been proved to be superior to DTPA. Their different bioactivities for decorporation of 234 Th were consistent with their competitive abilities to mobilize the thorium with bovine serum albumin. 7601 and 9501 could directly scavenge O 2 -. . Their effects as an O 2 -. scavenger were very significant and were similar to the of BESOD. The mechanism of protective effects of 7601 and 9501 for internal exposure injury was close related to decorporation effectiveness and the activity of scavenging oxygen free radical

Use of sulfur hexafluoride and perfluorocarbon tracers in plutonium storage containers for leak detection

International Nuclear Information System (INIS)

Kung, J.K.

1998-05-01

This study involves an investigation of the feasibility of a tracer-based leak detection system for long-term interim plutonium storage. In particular, a protocol has been developed based on the use of inert tracers with varying concentrations in order to open-quotes fingerprintclose quotes or open-quotes tagclose quotes specific containers. A particular combination of tracers at specific ratios could be injected into the free volume of each container, allowing for the detection of leaks as well as determination of the location of leaking containers. Based on plutonium storage considerations, sulfur hexafluoride and four perfluorocarbon tracers were selected and should allow a wide range of viable fingerprinting combinations. A open-quotes high-lowclose quotes protocol which uses two distinct chromatographic peak areas or concentration levels, is recommended. Combinations of air exchange rates, detection durations, and detectability limits are examined in order to predict minimum tracer concentrations required for injection in storage containers

Capital cost: high and low sulfur coal plants-1200 MWe. [High sulfur coal

Energy Technology Data Exchange (ETDEWEB)

1977-01-01

This Commercial Electric Power Cost Study for 1200 MWe (Nominal) high and low sulfur coal plants consists of three volumes. The high sulfur coal plant is described in Volumes I and II, while Volume III describes the low sulfur coal plant. The design basis and cost estimate for the 1232 MWe high sulfur coal plant is presented in Volume I, and the drawings, equipment list and site description are contained in Volume II. The reference design includes a lime flue gas desulfurization system. A regenerative sulfur dioxide removal system using magnesium oxide is also presented as an alternate in Section 7 Volume II. The design basis, drawings and summary cost estimate for a 1243 MWe low sulfur coal plant are presented in Volume III. This information was developed by redesigning the high sulfur coal plant for burning low sulfur sub-bituminous coal. These coal plants utilize a mechanical draft (wet) cooling tower system for condenser heat removal. Costs of alternate cooling systems are provided in Report No. 7 in this series of studies of costs of commercial electrical power plants.

Method of removing oxides of sulfur and oxides of nitrogen from exhaust gases

Science.gov (United States)

Walker, Richard J.

1986-01-01

A continuous method is presented for removing both oxides of sulfur and oxides of nitrogen from combustion or exhaust gases with the regeneration of the absorbent. Exhaust gas is cleaned of particulates and HCl by a water scrub prior to contact with a liquid absorbent that includes an aqueous solution of bisulfite and sulfite ions along with a metal chelate, such as, an iron or zinc aminopolycarboxylic acid. Following contact with the combustion gases the spent absorbent is subjected to electrodialysis to transfer bisulfite ions into a sulfuric acid solution while splitting water with hydroxide and hydrogen ion migration to equalize electrical charge. The electrodialysis stack includes alternate layers of anion selective and bipolar membranes. Oxides of nitrogen are removed from the liquid absorbent by air stripping at an elevated temperature and the regenerated liquid absorbent is returned to contact with exhaust gases for removal of sulfur oxides and nitrogen oxides.

Functionalized dithiocarbamate chelating resin for the removal of Co2+ from simulated wastewater

Science.gov (United States)

Shi, Xuewei; Fu, Linwei; Wu, Yanyang; Zhao, Huiling; Zhao, Shuangliang; Xu, Shouhong

2017-12-01

Industrial wastewater that contains trace amounts of heavy metal ions is often seen in petrochemical industry. While this wastewater can not be directly discharged, it is difficult to treat due to the low concentration of metal ions. Introducing chelating reagents into this wastewater for selective ion adsorption, followed by a mechanical separation process, provides an appealing solution. Toward the success of this technology, the development of effective chelating resins is of key importance. In the present work, a chelating resin containing amino and dithiocarbamate groups was reported for the removal of Co(II) metal ions in trace concentrations from simulated wastewater. By investigating the adsorption performance of the chelating resin at different solution pH values, adsorbent dosages, contact time, initial ion concentrations, and adsorption temperatures, the maximum adsorption capacity of the resin for Co(II) was identified to be 24.89 mg g-1 for a 2 g L-1 adsorbent dosage and a pH value of 5. After four adsorption-desorption cycles, 97% of the adsorption capacity of the resin was maintained. The adsorption kinetics and thermodynamics were analyzed and discussed as well.

The use of dihexyldithiocarbamate in reverse-phase HPLC of metal chelates

Science.gov (United States)

Fatimah, S. S.; Bahti, H. H.; Hastiawan, I.; Permanasari, A.

2018-05-01

Dialkyldithiocarbamates have long been used as chelating agents in reverse-phase HPLC of transition metals. In the previous study, an alkyl homolog of this type of ligand, namely dihexyldithiocarbamate (DHDTC), was synthesized and characterized. The use of this particular ligand in the revese-phase HPLC of some selected transition metal ions is now reported for the first time. The mobile phase comprising of the flow rate and of the detection, in the separation of the metal chelates of Cd (II), Fe (III), Cu (II), and Co (III), were investigated on a C-18 column. The results showed that dihexylditiocarbamate could be used for separating Cd (II), Fe(III), Cu(II), and Co(III). Therefore, it could be used in simultaneous analysis.

Quantitative Molecular Imaging with a Single Gd-Based Contrast Agent Reveals Specific Tumor Binding and Retention in Vivo.

Science.gov (United States)

Johansen, Mette L; Gao, Ying; Hutnick, Melanie A; Craig, Sonya E L; Pokorski, Jonathan K; Flask, Chris A; Brady-Kalnay, Susann M

2017-06-06

Magnetic resonance imaging (MRI) has become an indispensable tool in the diagnosis and treatment of many diseases, especially cancer. However, the poor sensitivity of MRI relative to other imaging modalities, such as PET, has hindered the development and clinical use of molecular MRI contrast agents that could provide vital diagnostic information by specifically locating a molecular target altered in the disease process. This work describes the specific and sustained in vivo binding and retention of a protein tyrosine phosphatase mu (PTPμ)-targeted, molecular magnetic resonance (MR) contrast agent with a single gadolinium (Gd) chelate using a quantitative MRI T 1 mapping technique in glioma xenografts. Quantitative T 1 mapping is an imaging method used to measure the longitudinal relaxation time, the T 1 relaxation time, of protons in a magnetic field after excitation by a radiofrequency pulse. T 1 relaxation times can in turn be used to calculate the concentration of a gadolinium-containing contrast agent in a region of interest, thereby allowing the retention or clearance of an agent to be quantified. In this context, retention is a measure of molecular contrast agent binding. Using conventional peptide chemistry, a PTPμ-targeted peptide was linked to a chelator that had been conjugated to a lysine residue. Following complexation with Gd, this PTPμ-targeted molecular contrast agent containing a single Gd ion showed significant tumor enhancement and a sustained increase in Gd concentration in both heterotopic and orthotopic tumors using dynamic quantitative MRI. This single Gd-containing PTPμ agent was more effective than our previous version with three Gd ions. Differences between nonspecific and specific agents, due to specific tumor binding, can be determined within the first 30 min after agent administration by examining clearance rates. This more facile chemistry, when combined with quantitative MR techniques, allows for widespread adoption by academic

Reaction of gadolinium chelates with ozone and hydroxyl radicals.

Science.gov (United States)

Cyris, Maike; Knolle, Wolfgang; Richard, Jessica; Dopp, Elke; von Sonntag, Clemens; Schmidt, Torsten C

2013-09-03

Gadolinium chelates are used in increasing amounts as contrast agents in magnetic resonance imaging, and their fate in wastewater treatment has recently become the focus of research. Oxidative processes, in particular the application of ozone, are currently discussed or even implemented for advanced wastewater treatment. However, reactions of the gadolinium chelates with ozone are not yet characterized. In this study, therefore, rate constants with ozone were determined for the three commonly used chelates Gd-DTPA, Gd-DTPA-BMA, and Gd-BT-DO3A, which were found to be 4.8 ± 0.88, 46 ± 2.5, and 24 ± 1.5 M(-1) s(-1), respectively. These low rate constants indicate that a direct reaction with ozone in wastewater is negligible. However, application of ozone in wastewater leads to substantial yields of (•)OH. Different methods have been applied and compared for determination of k((•)OH+Gd chelate). From rate constants determined by pulse radiolysis experiments (k((•)OH+Gd-DTPA) = 2.6 ± 0.2 × 10(9) M(-1) s(-1), k((•)OH+Gd-DTPA-BMA) = 1.9 ± 0.7 × 10(9) M(-1) s(-1), k((•)OH+Gd-BT-DO3A) = 4.3 ± 0.2 × 10(9) M(-1) s(-1)), it is concluded that a reaction in wastewater via (•)OH radicals is feasible. Toxicity has been tested for educt and product mixtures of both reactions. Cytotoxicity (MTT test) and genotoxicity (micronuclei assay) were not detectable.

Decontamination of chemical warfare sulfur mustard agent simulant by ZnO nanoparticles

Science.gov (United States)

Sadeghi, Meysam; Yekta, Sina; Ghaedi, Hamed

2016-07-01

In this study, zinc oxide nanoparticles (ZnO NPs) have been surveyed to decontaminate the chloroethyl phenyl sulfide as a sulfur mustard agent simulant. Prior to the reaction, ZnO NPs were successfully prepared through sol-gel method in the absence and presence of polyvinyl alcohol (PVA). PVA was utilized as a capping agent to control the agglomeration of the nanoparticles. The formation, morphology, elemental component, and crystalline size of nanoscale ZnO were certified and characterized by SEM/EDX, XRD, and FT-IR techniques. The decontamination (adsorption and destruction) was tracked by the GC-FID analysis, in which the effects of polarity of the media, such as isopropanol, acetone and n-hexane, reaction time intervals from 1 up to 18 h, and different temperatures, including 25, 35, 45, and 55 °C, on the catalytic/decontaminative capability of the surface of ZnO NPs/PVA were investigated and discussed, respectively. Results demonstrated that maximum decontamination (100 %) occurred in n-hexane solvent at 55 °C after 1 h. On the other hand, the obtained results for the acetone and isopropanol solvents were lower than expected. GC-MS chromatograms confirmed the formation of hydroxyl ethyl phenyl sulfide and phenyl vinyl sulfide as the destruction reaction products. Furthermore, these chromatograms proved the role of hydrolysis and elimination mechanisms on the catalyst considering its surface Bronsted and Lewis acid sites. A non-polar solvent aids material transfer to the reactive surface acid sites without blocking these sites.

Chelation therapy after the Trial to Assess Chelation Therapy: results of a unique trial

Science.gov (United States)

Avila, Maria D.; Escolar, Esteban; Lamas, Gervasio A.

2014-01-01

Purpose of review EDTA chelation therapy has been in off-label use for the treatment of atherosclerosis. We review the results of the first large-scale randomized trial of this treatment. Recent findings The trial to assess chelation therapy was a $30 million National Institutes of Health-funded study of the safety and efficacy of EDTA-based chelation infusions in 1708 post-myocardial infarction (MI) patients. The trial to assess chelation therapy demonstrated a significant (P = 0.035) 18% reduction in a combined primary endpoint of death, MI, stroke, coronary revascularization, or hospitalization for angina. In diabetic patients the benefit was more extreme, with a 41% relative reduction in risk (P = 0.0002) and a 43% reduction in total mortality (P = 0.011). Safety data were favorable. A reduction of oxidative stress by chelation of toxic metals has been proposed as a possible mechanism of action. Summary Recent research suggests that EDTA chelation may be a well-tolerated and effective treatment for post-MI patients. Future replication and mechanistic studies are important prior to implementation in all post-MI patients. PMID:25023079

Formation of CuxS Layers on Polypropylene Sulfurized by Molten Sulfur

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Rasa ALABURDAITĖ

2011-11-01

Full Text Available The processes of formation of electrically conductive layers of copper sulfides CuxS by the sorption-diffusion method on polypropylene (PP using molten sulfur as sulfurizing agent was investigated. The amount of sorbed sulfur increased with the increase of the duration of treatment. Copper sulfide layers were formed on the surface of polypropylene after the treatment of sulfurized polymer with Cu(II/I salt solution. The amount of copper sulfide in layer increased with the increase of treatment duration in copper salt solution. XRD spectra of PP films treated for 3 min with molten sulfur and then with Cu(II/I salt solution for the different time showed that the copper sulfide phases, mostly digenite, Cu2-xS and a-chalcocite, Cu2S were formed in the layers. Electromotive force measurement results confirmed the composition of formed CuxS layers on PP. The phase composition of layers also changed after the annealing. The value of electrical resistance of copper sulfide layers on PP varied from 20 W/cm2 to 80 W/cm2 and after annealing at 80 °C - in the interval of 10 W/cm2 - 60 W/cm2.http://dx.doi.org/10.5755/j01.ms.17.4.776

Preparation and Properties of the Chitosan/PVA Blend for Heavy Metals Chelation

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Zuhair Jabbar Abdul Ameer

2016-09-01

Full Text Available Current research based on the use of extracted chitosan mixed with Polyvinyl alcohol to manufacture blend that can been used in water purification from heavy metals such as copper, this due to chitosan properties and its ability to chelation these metals because of the presence of the functional groups in their structure. The blend has been treated with borax to increase the viscosity, and then high density polyethylene granulated coated with polymer solution to increase the surface area for chelation. The ultraviolet test showed the efficiency of blend to chelation of copper ions through lower the copper ions absorbance peak after each stage where the solution of copper ions pass on the polymer blend containing chitosan.

Evaluation of oral abdominal contrast agent containing ferric ammonium citrate

International Nuclear Information System (INIS)

Shiga, Toshiko; Kawamura, Yasutaka; Iwasaki, Toshiko

1991-01-01

We evaluated the effectiveness of oral MRI contrast agent containing ferric ammonium citrate. Twenty patients were arbitrarily divided into 2 groups according to the given dose of 100 and 200 mg Fe of oral MRI contrast agent. MRI was performed before and immediately after ingesting 300 ml solution of oral MRI contrast agent using a 1.5 T superconducting system (GE: Signa). Each dose of 100 and 200 mg Fe of oral MRI contrast agent produced sufficient enhancement of gastrointestinal tract, enough to make clear the pancreatic contour and porta hepatis. There was no significant change in blood and urine analysis observed after taking oral MRI contrast agent. The use of ferric ammonium citrate as an oral MRI contrast agent seems to add valuable information in performing upper abdominal MRI imaging. (author)

Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO2

International Nuclear Information System (INIS)

Brennecke, J.F.; Stadtherr, M.A.

1999-01-01

The overall objectives of this project were to gain a fundamental understanding of the solubility and phase behavior of metal chelates in supercritical CO 2 . Extraction with CO 2 is an excellent way to remove organic compounds from soils, sludges and aqueous solutions, and recent research has demonstrated that, together with chelating agents, it is a viable way to remove metals, as well. In this project the authors sought to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO 2 to separate organics and metal compounds from DOE mixed wastes. The overall program was a comprehensive one to measure, model and compute the solubility of metal chelate complexes in supercritical CO 2 and CO 2 /cosolvent mixtures. Through a combination of phase behavior measurements, spectroscopy and the development of a new computational technique, the authors have achieved a completely reliable way to model metal chelate solubility in supercritical CO 2 and CO 2 /co-contaminant mixtures. Thus, they can now design and optimize processes to extract metals from solid matrices using supercritical CO 2 , as an alternative to hazardous organic solvents that create their own environmental problems, even while helping in metals decontamination

Quantitative on-line analysis of sulfur compounds in complex hydrocarbon matrices.

Science.gov (United States)

Djokic, Marko R; Ristic, Nenad D; Olahova, Natalia; Marin, Guy B; Van Geem, Kevin M

2017-08-04

An improved method for on-line measurement of sulfur containing compounds in complex matrices is presented. The on-line system consists of a specifically designed sampling system connected to a comprehensive two-dimensional gas chromatograph (GC×GC) equipped with two capillary columns (Rtx ® -1 PONA×SGE BPX50), a flame ionization detector (FID) and a sulfur chemiluminescence detector (SCD). The result is an unprecedented sensitivity down to ppm level (1 ppm-w) for various sulfur containing compounds in very complex hydrocarbon matrices. In addition to the GC×GC-SCD, the low molecular weight sulfur containing compounds such as hydrogen sulfide (H 2 S) and carbonyl sulfide (COS) can be analyzed using a thermal conductivity detector of a so-called refinery gas analyzer (RGA). The methodology was extensively tested on a continuous flow pilot plant for steam cracking, in which quantification of sulfur containing compounds in the reactor effluent was carried out using 3-chlorothiophene as internal standard. The GC×GC-FID/-SCD settings were optimized for ppm analysis of sulfur compounds in olefin-rich (ethylene- and propylene-rich) hydrocarbon matrices produced by steam cracking of petroleum feedstocks. Besides that is primarily used for analysis of the hydrocarbon matrix, FID of the GC×GC-FID/-SCD set-up serves to double check the amount of added sulfur internal standard which is crucial for a proper quantification of sulfur compounds. When vacuum gas oil containing 780 ppm-w of elemental sulfur in the form of benzothiophenes and dibenzothiophenes is subjected to steam cracking, the sulfur balance was closed, with 75% of the sulfur contained in the feed is converted to hydrogen sulfide, 13% to alkyl homologues of thiophene while the remaining 12% is present in the form of alkyl homologues of benzothiophenes. The methodology can be applied for many other conversion processes which use sulfur containing feeds such as hydrocracking, catalytic cracking, kerogen

Toxicity of copper chelates of azomethines and amino acids for Chlorella pyrenoidosa

Energy Technology Data Exchange (ETDEWEB)

Barashkov, G.K.; Rukhadze, E.G.; Talyzenkova, G.P.

1979-01-01

The authors have attempted to assess the toxicity of copper-containing compounds from the point of view of their interrelationship with the structural characteristics of the chelate compound and the structure of the ligand. The copper chelates of the azomethines tested may be provisionally divided into three types: A - complexes with N-alkly-azomethines; B - complexes with N-aryl-azomethines; C - binuclear complexes. Consideration was also given to chelates with aromatic and heterocyclic amino acids and to heteroligand chelates in which the copper atom coordinates azomethine and an amino acid simultaneously. Toxicity was determined by the method previously described and expressed as a critical concentration (C/sub cr/, mg Cu/liter) and in relative toxicity units (T/sub c/). The compounds investigated were obtained from the interaction between a bidentant ligand of an azomethine or anamino acid and copper acetate in a water-alcohol medium at pH 6-8. Since they are not very soluble in water, true solutions were obtained by using dimethyl sulfoxide.

Beliefs about chelation among thalassemia patients

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Trachtenberg Felicia L

2012-12-01

Full Text Available Abstract Background Understanding patients’ views about medication is crucial to maximize adherence. Thalassemia is a congenital blood disorder requiring chronic blood transfusions and daily iron chelation therapy. Methods The Beliefs in Medicine Questionnaire (BMQ was used to assess beliefs in chelation in thalassemia patients from North America and London in the Thalassemia Longitudinal Cohort (TLC of the Thalassemia Clinical Research Network (TCRN. Chelation adherence was based on patient report of doses administered out of those prescribed in the last four weeks. Results Of 371 patients (ages 5-58y, mean 24y, 93% were transfused and 92% receiving chelation (26% deferoxamine (DFO; a slow subcutaneous infusion via portable pump, 63% oral, 11% combination. Patients expressed high “necessity” for transfusion (96%, DFO chelation (92% and oral chelation (89%, with lower “concern” about treatment (48%, 39%, 19% respectively. Concern about oral chelation was significantly lower than that of DFO (p Conclusions Despite their requirement for multimodal therapy, thalassemia patients have positive views about medicine, more so than in other disease populations. Patients may benefit from education about the tolerability of chelation and strategies to effectively cope with side effects, both of which might be beneficial in lowering body iron burden. Clinicaltrials.gov identifier NCT00661804

Chelating polymeric membranes

KAUST Repository

Peinemann, Klaus-Viktor

2015-01-22

The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

Danburite decomposition by sulfuric acid

International Nuclear Information System (INIS)

Mirsaidov, U.; Mamatov, E.D.; Ashurov, N.A.

2011-01-01

Present article is devoted to decomposition of danburite of Ak-Arkhar Deposit of Tajikistan by sulfuric acid. The process of decomposition of danburite concentrate by sulfuric acid was studied. The chemical nature of decomposition process of boron containing ore was determined. The influence of temperature on the rate of extraction of boron and iron oxides was defined. The dependence of decomposition of boron and iron oxides on process duration, dosage of H 2 SO 4 , acid concentration and size of danburite particles was determined. The kinetics of danburite decomposition by sulfuric acid was studied as well. The apparent activation energy of the process of danburite decomposition by sulfuric acid was calculated. The flowsheet of danburite processing by sulfuric acid was elaborated.

The effect of sulfur on the inhibition of PCDD/F formation during co-combustion of coal and solid waste

Energy Technology Data Exchange (ETDEWEB)

Palladas, A. [Laboratory of Environmental and Energy Processes, Thermi-Thessaloniki (Greece). Chemical Process Engineering Research Institute; Samaras, P. [TEI of Western Macedonia, Kozani (Greece). Dept. of Environmental Technology; Sakellaropoulos, G. [Aristotle Univ. of Thessaloniki (Greece). Dept. of Chemical Engineering

2004-09-15

Co-combustion of solid wastes with coal is a promising technique used to reduce landfilled wastes, utilizing waste the energy content. However, solid wastes often contain chlorine and other substances, which upon combustion may result in the production of extremely toxic compounds like polychlorinated dibenzo-p-dioxins and dibenzofurans. Various compounds have been proposed for their inhibition ability of PCDD/F formation, including sulphuric and nitrogen containing substances. Sulfur compounds may form some kind of complexes with metal species, reducing thus their ability for catalysing the PCDD/F formation pathways. Sulfur inhibitory capacity has been attributed to reaction with copper catalytic sites, altering their form and presumably their ability to produce Cl{sub 2} through the Deacon process reaction. Another second postulated role of sulfur is to undergo homogeneous reactions, converting the primary chlorinating agent, Cl{sub 2}, into a form (HCl) less likely to undergo aromatic substitution reactions forming PCDD/F precursors. The objectives of this work were the measurement of PCDD/F emissions during co-combustion of different fuel mixtures, and the study of the effect of sulfur addition to the fuel on PCDD/F formation.

Biologically removing sulfur from dilute gas flows

Science.gov (United States)

Ruitenberg, R.; Dijkman, H.; Buisman, C. J. N.

1999-05-01

A biological process has been developed to clean off-gases containing sulfur dioxide from industrial installations. The sulfur dioxide is converted into hydrogen sulfide, which can then be oxidized to elemental sulfur if not used on-site. The process produces no waste products that require disposal and has a low reagent consumption.

Application of Atmospheric Pressure Photoionization H/D-exchange Mass Spectrometry for Speciation of Sulfur-containing Compounds.

Science.gov (United States)

Acter, Thamina; Kim, Donghwi; Ahmed, Arif; Ha, Ji-Hyoung; Kim, Sunghwan

2017-08-01

Herein we report the observation of atmospheric pressure in-source hydrogen-deuterium exchange (HDX) of thiol group for the first time. The HDX for thiol group was optimized for positive atmospheric pressure photoionization (APPI) mass spectrometry (MS). The optimized HDX-MS was applied for 31 model compounds (thiols, thiophenes, and sulfides) to demonstrate that exchanged peaks were observed only for thiols. The optimized method has been successfully applied to the isolated fractions of sulfur-rich oil samples. The exchange of one and two thiol hydrogens with deuterium was observed in the thiol fraction; no HDX was observed in the other fractions. Thus, the results presented in this study demonstrate that the HDX-MS method using APPI ionization source can be effective for speciation of sulfur compounds. This method has the potential to be used to access corrosion problems caused by thiol-containing compounds. Graphical Abstract ᅟ.

Plutonium uptake by plants from soil containing plutonium-238 dioxide particles. Final report

International Nuclear Information System (INIS)

Brown, K.W.; McFarlane, J.C.

1977-05-01

Three plant species--alfalfa, lettuce, and radishes were grown in soils contaminated with plutonium-238 dioxide (238)PuO2 at concentrations of 23, 69, 92, and 342 nanocuries per gram (nCi/g). The length of exposure varied from 60 days for the lettuce and radishes to 358 days for the alfalfa. The magnitude of plutonium incorporation as indicated by the discrimination ratios for these species, after being exposed to the relatively insoluble PuO2, was similar to previously reported data using different chemical forms of plutonium. Evidence indicates that the predominant factor in plutonium uptake by plants may involve the chelation of plutonium contained in the soils by the action of compounds such as citric acid and/or other similar chelating agents released from the plant roots

Efficacy and role of inulin in mitigation of enteric sulfur-containing odor in pigs.

Science.gov (United States)

Deng, Yuan-Fan; Liu, Yuan-Yuan; Zhang, Yi-Tao; Wang, Yan; Liang, Juan-Boo; Tufarelli, Vincenzo; Laudadio, Vito; Liao, Xin-Di

2017-06-01

The efficacy and role of inulin in the mitigation of enteric sulfur-containing odor gases hydrogen sulfide (H 2 S) and methyl mercaptan (CH 3 SH) in pigs were examined in this study. Twelve Duroc × Landrace × Yorkshire male finisher pigs (60.7 ± 1.9 kg), housed individually in open-circuit respiration chambers, were randomly assigned to two dietary groups, namely basal diet (control) and basal diet supplemented with 1% (w/w) inulin. At the end of the 45 day experiment, pigs were slaughtered and volatile fatty acid (VFA) concentration, sulfate radical (SO 4 2 - ) concentration, population of sulfate-reducing bacteria (SRB) and expression of methionine gamma-lyase (MGL) gene were determined in contents from the caecum, colon (two segments) and rectum. Metabonomic analysis was used to compare differences in biochemical composition, and the Illumina MiSeq procedure to investigate differences in bacterial components, in the different parts of the large intestine between inulin-supplemented and inulin-free (control) groups. Inulin decreased (P inulin treatment, whereas valerate concentration and MGL mRNA expression decreased (P inulin-supplemented pigs, suggesting that inulin mitigates H 2 S generation from the SO 4 2 - reduction pathway by reducing the growth of SRB. The results showed that inulin mitigates CH 3 SH generation via three methionine degradation metabolic pathways and H 2 S generation from two cysteine degradation metabolic pathways, thus resulting in increased synthesis of these two sulfur-containing amino acids in the pig large intestine. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Chelating effect of silver nitrate by chitosan on its toxicity and growth performance in broiler chickens

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Yemdjie Mane Divine Doriane

2017-06-01

Full Text Available Objective: This study was conducted to investigate the chelating effect of silver nitrate (AgNO3 by chitosan on growth performances, hematological and biochemical parameters, and the histopathological structure of the liver and the kidney in broiler chicken. Materials and methods: A total of 192 day-old Cobb 500 strain chicks were randomly assigned to 3 treatments of 64 chicks each. Control group was fed on basal diet without supplement (R0 and the two others groups were fed on rations supplemented with 10 mg of unchelated (RAg or chelated (RCs-Ag AgNO3 per Kg of feed, respectively. Parameters that have been studied consisted of feed intake, weight gain, blood and serum biochemical, and histopathological analyses of liver and kidney. Results: Results revealed that chelation of AgNO3 by chitosan did not have any effect on growth performances and hematological parameters in chicken. However, chelated and unchelated AgNO3 increased the serum content in triglyceride, and cholesterol and decreased the serum content in creatinin, albumin and alanine aminotransferase (ALAT. Chelating AgNO3 with chitosan prevented and corrected the toxicity induced on the histological structure of liver and kidney. Conclusion: Chitosan can be used as a chelating agent to alleviate the harmful effects of AgNO3 as silver ion for poultry. [J Adv Vet Anim Res 2017; 4(2.000: 187-193

Preparation and Evaluation of Multiple Nanoemulsions Containing Gadolinium (III) Chelate as a Potential Magnetic Resonance Imaging (MRI) Contrast Agent.

Science.gov (United States)

Sigward, Estelle; Corvis, Yohann; Doan, Bich-Thuy; Kindsiko, Kadri; Seguin, Johanne; Scherman, Daniel; Brossard, Denis; Mignet, Nathalie; Espeau, Philippe; Crauste-Manciet, Sylvie

2015-09-01

The objective was to develop, characterize and assess the potentiality of W1/O/W2 self-emulsifying multiple nanoemulsions to enhance signal/noise ratio for Magnetic Resonance Imaging (MRI). For this purpose, a new formulation, was designed for encapsulation efficiency and stability. Various methods were used to characterize encapsulation efficiency ,in particular calorimetric methods (Differential Scanning Calorimetry (DSC), thermogravimetry analysis) and ultrafiltration. MRI in vitro relaxivities were assessed on loaded DTPA-Gd multiple nanoemulsions. Characterization of the formulation, in particular of encapsulation efficiency was a challenge due to interactions found with ultrafiltration method. Thanks to the specifically developed DSC protocol, we were able to confirm the formation of multiple nanoemulsions, differentiate loaded from unloaded nanoemulsions and measure the encapsulation efficiency which was found to be quite high with a 68% of drug loaded. Relaxivity studies showed that the self-emulsifying W/O/W nanoemulsions were positive contrast agents, exhibiting higher relaxivities than those of the DTPA-Gd solution taken as a reference. New self-emulsifying multiple nanoemulsions that were able to load satisfactory amounts of contrasting agent were successfully developed as potential MRI contrasting agents. A specific DSC protocol was needed to be developed to characterize these complex systems as it would be useful to develop these self-formation formulations.

Isotopic measurement of uranium using NP-type chelate resin beads

International Nuclear Information System (INIS)

Wu Lanbi; Chen Wenpo; Wang Shijun

1994-08-01

NP-type chelate resin beads is used as a carrier of samples in the isotopic measurements of uranium by mass spectrometry. The results show that its absorption efficiency for uranium can be greater than 50%. It is one order magnitude higher than that strong basic anion resin, however, the ionization efficiencies of both are almost the same. Therefore, the amount of uranium required for isotopic analysis can be reduced one order of magnitude. This method has been used for isotopic analysis of uranium in NP-type chelate resin beads contained 10 -9 ∼ 10 -7 g uranium. For standard sample UTB-500, the external precision of measurements are within +-0.2%, for natural uranium samples are within +- 0.5%. The application of NP-type chelate resin beads in the isotopic measurement of uranium is a new creative achievement. It has been used in the depletion test of uranium-atomic vapor laser isotope separation

Reducing surface tension in endodontic chelator solutions has no effect on their ability to remove calcium from instrumented root canals.

Science.gov (United States)

Zehnder, Matthias; Schicht, Olivier; Sener, Beatrice; Schmidlin, Patrick

2005-08-01

The aim of this study was to evaluate the effect of reducing surface tension in endodontic chelator solutions on their ability to remove calcium from instrumented root canals. Aqueous solutions containing 15.5% EDTA, 10% citric acid, or 18% 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP) were prepared with and without 1% (wt/wt) polysorbate (Tween) 80 and 9% propylene glycol. Surface tension in these solutions was measured using the Wilhelmy method. Sixty-four extracted, single-rooted human teeth of similar length were instrumented and irrigated with a 1% sodium hypochlorite solution and then randomly assigned (n = 8 per group) to receive a final one-minute rinse with 5 ml of test solutions, water, or the pure aqueous Tween/propylene glycol solution. Calcium concentration in eluates was measured using atomic absorption spectrometry. Incorporation of wetting agents resulted in a reduction of surface tension values by approximately 50% in all tested solutions. However, none of the solutions with reduced surface tension chelated more calcium from canals than their pure counterparts (p > 0.05).

Electrochemical reduction of sulfur dioxide in sulfolane

Energy Technology Data Exchange (ETDEWEB)

Vorob' ev, A.S.; Gavrilova, A.A.; Kolosnitsyn, V.S.; Nikitin, Yu.E.

1985-09-01

Solutions of sulfur dioxide in aproptic media are promising electrolyte oxidizing agents for chemical current sources with anodes of active metals. This work describes the electrochemical reduction of sulfur dioxide in sulfolane in a lithium halide supporting electrolyte which was investigated by the methods of voltamperometry and chronopotentiometry. The dependence of the current of the cathodic peak on the concentration of the supporting electrolyte salts, sulfur dioxide and water, was studied. On the basis of the data obtained, a hypothesis was advanced on the nature of the limiting step. The investigation showed that at low polarizing current densities, a substantial influence on the reduction of sulfur dioxide in sulfolane in a lithium halide supporting electrolyte is exerted by blockage of the electrode surface by sparingly soluble reaction products.

Sensing sulfur oxides and other sulfur bearing pollutants with solid electrolyte pellets. I. Gas concentration cells

Energy Technology Data Exchange (ETDEWEB)

Chamberland, A M; Gauthier, J M

1977-01-01

A new sensing technique using a solid electrolyte has been demonstrated for sulfur-bearing pollutants. Based on potentiometric measurements across a pellet of potassium sulfate, this sensor allows concentrations of sulfur dioxides, sulfur trioxide, hydrogen sulfide, methyl mercaptan and carbonyl sulfide in air to be measured with accuracy. Its operational concentration range at the present time is 0.1 ppM up to at least 10,000 ppM. The presence of other common pollutants such as carbon dioxide, methane, nitric oxide and nitrogen dioxide does not interfere with the measurement of air samples containing sulfur-bearing pollutants.

Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO2. Annual progress report, September 15, 1996 - September 14, 1997

International Nuclear Information System (INIS)

Brennecke, J.F.; Chateauneuf, J.E.; Stadtherr, M.A.

1997-01-01

'This progress report contains (1) a statement of the objectives of the overall project, (2) a discussion of the results obtained during the first year of the three year grant period, (3) a summary, (4) a description of the future work that will be pursued during the next year, and (5) accounting information. This is followed by the literature cited and the pertinent tables and figures. The overall objectives of this project are to gain a fundamental understanding of the solubility and stability of metal chelates in supercritical CO 2 . Extraction with CO 2 is a excellent way to remove organic compounds from soils, sludges and aqueous solutions and recent research has demonstrated that together with chelating agents it is a viable way to remove metals, as well. The authors seek to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO 2 to separate organics and metal compounds from DOE mixed wastes. The overall program is a comprehensive one to measure local solvation of metal chelates and to determine metal chelate stability in supercritical fluid mixtures using UV-vis and FTIR spectroscopy. The spectroscopic studies provide information on the solution microstructure, which they are using in concert with their own and published solubility data to evaluate and develop thermodynamic models of the solubility behavior. Finally, they are implementing a more reliable computational technique, based on interval mathematics, to compute the phase equilibria using the thermodynamic models. This fundamental information about metal chelate stability and solubility in supercritical CO 2 is important in the design of processes using CO 2 to extract components from mixed wastes and in determining the optimum operating conditions.'

Development of novel processes for Cu concentrates without producing sulfuric acid; Hiryusan hasseigata no atarashii doshigen shori gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Awakura, Y; Hirato, T [Kyoto University, Kyoto (Japan)

1997-02-01

Studies are conducted to develop a new wet method for copper concentrates to replace the conventional dry smelting method for the settlement of problems involving the processing of impurities for environmental protection. A specimen of pyrites polycrystals is subjected to leaching at 80 {degree}C in a strongly acidic cupric solution. Findings are that the element sulfur generated in this process does not impede leaching and only approximately 4% of the sulfur is oxidized into sulfur ions; that the presence of more than 2g/liter of bromide ions produced during bromine-aid leaching of gold changes the structure of sulfur for the inhibition of leaching; that circulation of a bromine-containing leaching liquid is not desired since even a small amount of approximately 0.02mol/liter inhibits the leaching rate. Controlled potential electrolysis is performed for the anode in an acid solution containing CuCl, NaCl, and NaBr, for the observation of oxidation/reduction potentials predicted by Nernst`s equation. It is then disclosed that bromine is more effective than chlorine in gold leaching and that the solution potential during leaching agent regeneration enables the monitoring of solution constitution. 2 refs.

Process for treating the dialyzed spent liquor from sulphonic acid containing sulfur minerals or tar oils or ammonium salts

Energy Technology Data Exchange (ETDEWEB)

Wernicke, E A

1936-08-09

Process for working up the dialyzate from sulfonic acid, sulfur-containing mineral or tar oils, or their ammonium salts, characterized by the combination of known steps, in the dialyzate being reacted with alkaline-earth oxide, hydroxide, or carbonate, and the resulting slightly soluble sulfate being filtered off and evaporated if necessary.

Chemical Agents

Science.gov (United States)

... CR) see Riot Control Agents Digitalis Distilled mustard (HD) see Sulfur mustard E Ethylene glycol F Fentanyls and other opioids H Hydrazine Hydrofluoric acid (hydrogen fluoride) Hydrogen chloride Hydrogen cyanide (AC) Hydrogen ...

The interaction of MRI contrast agents with phospholipids

International Nuclear Information System (INIS)

Jendrasiak, Gordon L.; Smith, Ralph L.; Ribeiro, Anthony A.

2000-01-01

The molecular interactions of three clinically used MRI contrast agents with lipid vesicles, consisting of egg phosphatidylcholine (EPC), have been studied using high-field NMR techniques. At a molar ratio of one contrast agent molecule to five phospholipid molecules, a significant increase in the proton resonance line width occurred for certain lipid head group moieties. A large decrease in the T 1 relaxation times for the head group moieties was also observed. These two effects occurred regardless of the ionic status and the chelate structure of the three contrast agents. The structure of the contrast agents did, however, affect the magnitude of the two NMR parameter changes. These NMR effects also differed in magnitude amongst the various head group entities. The NMR effects were greatest for the head group moieties at or near the vesicle-water interface. The results are discussed in terms of the structure of the phospholipid-water interface. Since the use of contrast agents has become routine in clinical MRI, our results are of importance in terms of the interaction of the agents with physiological surfaces, many of which contain phospholipids. The understanding of such interactions should be of value not only for improved diagnostics, but also in the development of new contrast agents. (author)

Effectively simultaneous naked-eye detection of Cu(II), Pb(II), Al(III) and Fe(III) using cyanidin extracted from red cabbage as chelating agent

Science.gov (United States)

Khaodee, Warangkhana; Aeungmaitrepirom, Wanlapa; Tuntulani, Thawatchai

Simultaneous determination of Cu(II), Pb(II), Al(III) and Fe(III) using cyanidin as a chelating agent was investigated in terms of both quantitative and qualitative detections. Cyanidin was extracted and purified from red cabbage which is a local plant in Thailand. The selectivity of this method was examined by regulating the pH of cyanidin solution operated together with masking agents. It was found that Cu(II), Pb(II), Al(III) and Fe(III) simultaneously responded with the color change at pH 7, pH 6, pH 5 and pH 4, respectively. KF, DMG and the mixture of KF and DMG were used as masking agents for the determination of Fe(III), Al(III) and Pb(II), respectively. Results from naked-eye detection were evaluated by comparing with those of inductively coupled plasma (ICP), and there was no significant difference noticed. Cyanidin using as a multianalyte reagent could be employed for simultaneous determination of Cu(II), Pb(II), Al(III) and Fe(III) at the lowest concentration at 50, 80, 50 and 200 μM, respectively, by slightly varying pHs. Moreover, the proposed method could be potentially applied for real water samples with simplicity, rapidity, low cost and environmental safety.

Extraction of Uranium in The Mixtures of Nitric and Sulfuric Acids With Neutral and Basic Ligands in Kerosene

International Nuclear Information System (INIS)

Nampira, Y; Rahayu Imam, S; Djoyosubroto, H

1998-01-01

The tendency of uranium ion in the mixture of nitric and sulfuric acid's medium is to from uranyl sulphate complex. The compound of uranyl sulphate is containing into the heteropoly compound that has acid property. Regarding to the mentioned property, the U extraction process was carried out using a basic or neutral complexing agent containing a ligand that formed the soluble uranium complex in the organic solvent (kerosene).The use of basic complexing agent such as n,tri-octyl amine is more suitable than that of tri butyl phosphate as a neutral agent. The maximum distribution coefficient of uranium will be reached if the maximum concentration of nitric acid and sulphuric acid can be maintained at 0.3 M and 1.5 M respectively in the organic solvent medium consisted n,tri-octyl amine of 30% volume fraction

Design and Optimization of Gadolinium Based Contrast Agents for Magnetic Resonance Imaging

International Nuclear Information System (INIS)

Pereira, G.A.; Geraldes, C.F.G.C.; University of Coimbra

2007-01-01

The role of Gd 3+ chelates as contrast agents in Magnetic Resonance Imaging is discussed. The theory describing the different contributions to paramagnetic relaxation relevant to the understanding of the molecular parameters determining the relativity of those Gd 3+ chelates, is presented. The experimental techniques used to obtain those parameters are also described. Then, the various approaches taken to optimize those parameters, leading to maximum relativity (efficiency) of the contrast agents, are also illustrated with relevant examples taken from the literature. The various types of Gd 3+ -based agents, besides non-specific and hepatobiliary agents, are also discussed, namely blood pool, targeting, responsive and paramagnetic chemical shift saturation transfer (PARACEST) agents. Finally, a perspective is presented of some of the challenges lying ahead in the optimization of MRI contrast agents to be useful in Molecular Imaging. (author)

A general chelate-assisted co-assembly to metallic nanoparticles-incorporated ordered mesoporous carbon catalysts for Fischer-Tropsch synthesis.

Science.gov (United States)

Sun, Zhenkun; Sun, Bo; Qiao, Minghua; Wei, Jing; Yue, Qin; Wang, Chun; Deng, Yonghui; Kaliaguine, Serge; Zhao, Dongyuan

2012-10-24

The organization of different nano objects with tunable sizes, morphologies, and functions into integrated nanostructures is critical to the development of novel nanosystems that display high performances in sensing, catalysis, and so on. Herein, using acetylacetone as a chelating agent, phenolic resol as a carbon source, metal nitrates as metal sources, and amphiphilic copolymers as a template, we demonstrate a chelate-assisted multicomponent coassembly method to synthesize ordered mesoporous carbon with uniform metal-containing nanoparticles. The obtained nanocomposites have a 2-D hexagonally arranged pore structure, uniform pore size (~4.0 nm), high surface area (~500 m(2)/g), moderate pore volume (~0.30 cm(3)/g), uniform and highly dispersed Fe(2)O(3) nanoparticles, and constant Fe(2)O(3) contents around 10 wt %. By adjusting acetylacetone amount, the size of Fe(2)O(3) nanoparticles is readily tunable from 8.3 to 22.1 nm. More importantly, it is found that the metal-containing nanoparticles are partially embedded in the carbon framework with the remaining part exposed in the mesopore channels. This unique semiexposure structure not only provides an excellent confinement effect and exposed surface for catalysis but also helps to tightly trap the nanoparticles and prevent aggregating during catalysis. Fischer-Tropsch synthesis results show that as the size of iron nanoparticles decreases, the mesoporous Fe-carbon nanocomposites exhibit significantly improved catalytic performances with C(5+) selectivity up to 68%, much better than any reported promoter-free Fe-based catalysts due to the unique semiexposure morphology of metal-containing nanoparticles confined in the mesoporous carbon matrix.

Effects of mineral matter on products and sulfur distributions in hydropyrolysis

Energy Technology Data Exchange (ETDEWEB)

Chen, H.; Li, B.; Zhang, B. [Chinese Academy of Sciences, Taiyuan (China). Inst. of Coal Chemistry

1999-05-01

The effects of the mineral matter on the product yield and sulfur distribution in hydropyrolysis and pyrolysis of Chinese Hongmiao lignite were investigated using a fixed-bed reactor. The volatile sulfur-containing gases (H{sub 2}S, COS, CH{sub 3}SH) were also analyzed as a function of pyrolysis temperature. Coal samples were treated with HCl/HF or HCl/HF and CrCl{sub 2} solution to eliminate minerals and pyrite respectively. In hydropyrolysis, demineralized Hongmiao lignite showed lower yields of tar and water than the raw coal. Demineralization cannot only minimize the fixation effect of basic mineral matter on sulfur-containing gases, but also increase the sulfur distribution of the tar. Further, from the evolution profiles of sulfur-containing gases, it is possible to elucidate the contribution of minerals, pyrite and organic sulfur to the sulfur evolution. Pyrite may not be the only source of COS formation. 32 refs., 14 figs., 3 tabs.

Restraint stress in lactating mice alters the levels of sulfur-containing amino acids in milk.

Science.gov (United States)

Nishigawa, Takuma; Nagamachi, Satsuki; Ikeda, Hiromi; Chowdhury, Vishwajit S; Furuse, Mitsuhiro

2018-03-30

It is well known that maternal stress during the gestation and lactation periods induces abnormal behavior in the offspring and causes a lowering of the offspring's body weight. Various causes of maternal stress during the lactation period, relating to, for example, maternal nutritional status and reduced maternal care, have been considered. However, little is known about the effects on milk of maternal stress during the lactation period. The current study aimed to determine whether free amino acids, with special reference to sulfur-containing amino acids in milk, are altered by restraint stress in lactating mice. The dams in the stress group were restrained for 30 min at postnatal days 2, 4, 6, 8, 10 and 12. Restraint stress caused a reduction in the body weight of lactating mice. The concentration of taurine and cystathionine in milk was significantly higher in the stress group, though stress did not alter their concentration in maternal plasma. The ratio of taurine concentration in milk to its concentration in maternal plasma was significantly higher in the stress group, suggesting that stress promoted taurine transportation into milk. Furthermore, taurine concentration in milk was positively correlated with corticosterone levels in plasma. In conclusion, restraint stress in lactating mice caused the changes in the metabolism and in the transportation of sulfur-containing amino acids and resulted in higher taurine concentration in milk. Taurine concentration in milk could also be a good parameter for determining stress status in dams.

Chemical protection of bacteria and cultured mammalian cells by sulfur--containing compounds

Energy Technology Data Exchange (ETDEWEB)

Antoku, S [Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology

1975-03-01

Protection by sulfur-containing compounds was studied using bacteria E. coli Bsub(H) and cultured mouse leukemic cells, L 5178 Y. The protective mechanisms are discussed. The dose reduction factors of non-sulfhydryl compounds observed in the bacteria were the same as those observed in mammalian cells, and the protective activity of these compounds was proportional to their reaction rates with hydroxyl radicals. On the other hand, sulfhydryl compounds, with the exception of glutathione, offered a much greater protection than was anticipated from their radical scavenging activity. From studies under anoxia, the protection of cysteine was explained by its OH scavenging and competition with oxygen. In addition, for MEA, protection against the direct action of radiation was suggested. This was supported by the significant protection in the frozen state.

Removal of sulfur from process streams

International Nuclear Information System (INIS)

Brignac, D.G.

1984-01-01

A process wherein water is added to a non-reactive gas stream, preferably a hydrogen or hydrogen-containing gas stream, sufficient to raise the water level thereof to from about 0.2 percent to about 50 percent, based on the total volume of the process gas stream, and the said moist gas stream is contacted, at elevated temperature, with a particulate mass of a sulfur-bearing metal alumina spinel characterized by the formula MAl 2 O 4 , wherein M is chromium, iron, cobalt, nickel, copper, cadmium, mercury, or zinc to desorb sulfur thereon. In the sulfur sorption cycle, due to the simultaneous adsorption of water and sulfur, the useful life of the metal alumina spinel for sulfur adsorption can be extended, and the sorbent made more easily regenerable after contact with a sulfur-bearing gas stream, notably sulfur-bearing wet hydrogen or wet hydrogen-rich gas streams

Comparative study of reactions between µ-nitrido- or µ-oxo-bridged iron tetrasulfophthalocyanines and sulfur-containing reductants

Directory of Open Access Journals (Sweden)

Dereven’kov Ilia A.

2013-01-01

Full Text Available A comparative study of reactivity of μ-nitrido- and μ-oxo-dimers of iron tetrasulfophthalocyanine has been performed in aqueous solutions of various acidity. The substantially higher stability of nitrido-bridged structure under both strongly acidic and strongly alkaline environments was demonstrated. Reactions of the complexes with sulfur-containing reductants (sodium dithionite, thiourea dioxide, sodium hydroxymethanesulfinate, L-cysteine has been studied. Differences in reduction processes were explained.

Sulfur contents and sulfur-isotope compositions of thiotrophic symbioses in bivalve molluscs and vestimentiferan worms

Science.gov (United States)

Vetter, R.D.; Fry, B.

1998-01-01

Total sulfur (S(TOT)), elemental sulfur (S??) and sulfur-isotope compositions (??34S) of marine animals were analyzed to determine whether these chemical characteristics could help distinguish animals with a sulfur-based, thiotrophic nutrition from animals whose nutrition is based on methanotrophy or on more normal consumption of phytoplankton-derived organic matter. The presence of S??was almost entirely confined to the symbiont-containing tissues of thiotrophs, but was sometimes undetectable in thiotrophic species where sulfide availability was probably low. When S??contents were subtracted, the remaining tissue-sulfur concentrations were similar for all nutritional groups. ??34S values were typically lower for thiotrophs than for other groups, although there was overlap in methanotroph and thiotroph values at some sites. Field evidence supported the existence of small to moderate (1 to 10???)34S fractionations in the uptake of sulfides and metabolism of thiosulfate. In general, a total sulfur content of >3% dry weight, the presence of elemental sulfur, and ??34S values less than + 5??? can be used to infer a thiotrophic mode of nutrition.

Stress Corrosion Cracking of Ni-base Alloys in Sulfur Containing Solutions at 340 .deg. C

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Hee; Hwang, Seong Sik; Kim, Dong Jin; Kim, Sung Woo [KAERI, Daejeon (Korea, Republic of)

2016-05-15

Sulfur has been identified as one of the major impurities introduced into the secondary water of pressurized water-reactors (PWRs). Sulfur can originate from various sources, such as resin sources, feed water, cooling water in-leakage, and condenser leaks. Many authors have investigated effects of reduced sulfur in a wide pH range with or without additives. The presence of reduced sulfur species on the surfaces of pulled tubes having stress corrosion cracking (SCC) was also identified. In present work, SCC tests were conducted to investigate effects of reduced sulfur species on the SCC behavior of Ni-base Alloys. The Alloy 690 TT showed the most SCC resistant, regardless of the sulfur species. The Cr content and heat treatments of alloys appeared the increase in the SCC resistance.

Induction and repair of DNA cross-links induced by sulfur mustard in the A-549 cell line followed by a comet assay.

Science.gov (United States)

Jost, Petr; Svobodova, Hana; Stetina, Rudolf

2015-07-25

Sulfur mustard is a highly toxic chemical warfare agent with devastating impact on intoxicated tissues. DNA cross-links are probably the most toxic DNA lesions induced in the cell by sulfur mustard. The comet assay is a very sensitive method for measuring DNA damage. In the present study using the A-549 lung cell line, the comet assay protocol was optimized for indirect detection of DNA cross-links induced by sulfur mustard. The method is based on the additional treatment of the assayed cells containing cross-links with the chemical mutagen, styrene oxide. Alkali-labile adducts of styrene oxide cause DNA breaks leading to the formation of comets. A significant dose-dependent reduction of DNA migration of the comet's tail was found after exposing cells to sulfur mustard, indicative of the amount of sulfur mustard induced cross-links. The remarkable decrease of % tail DNA could be observed as early as 5min following exposure to sulfur mustard and the maximal effect was found after 30min, when DNA migration was reduced to the minimum. Sulfur mustard preincubated in culture medium without cells lost its ability to induce cross-links and had a half-life of about 15min. Pre-incubation longer than 30min does not lead to a significant increase in cross-links when applied to cells. However, the amount of cross-links is decreased during further incubation due to repair. The current modification of the comet assay provides a useful tool for detecting DNA cross-links induced by sulfur mustard and could be used for detection of other DNA cross-linking agents such as chemotherapeutic drugs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

To chelate or not to chelate in MDS: That is the question!

Science.gov (United States)

Zeidan, Amer M; Griffiths, Elizabeth A

2018-03-08

Myelodysplastic syndromes (MDS) are a heterogeneous group of hemopathies that exhibit physical manifestations with clinical consequences of bone marrow failure and inherent risk of progression to acute myeloid leukemia. Iron overload (IO) is common in MDS due to chronic transfusion support and disease-related alterations in iron metabolism. IO has been conclusively associated with inferior outcomes among MDS patients. Despite lack of randomized trials showing a survival impact of iron chelation therapy (ICT), ICT is recommended by experts and guidelines for select MDS patients with IO and is often used. The availability of effective oral ICT agents has reignited the controversy regarding ICT use in patients with MDS and IO. Here we summarize the studies evaluating the value of ICT in MDS and suggest a practical approach for use of these therapies. We also highlight controversies regarding use of ICT in MDS and discuss some ongoing efforts to answer these questions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Advanced Sulfur Cathode Enabled by Highly Crumpled Nitrogen-Doped Graphene Sheets for High-Energy-Density Lithium-Sulfur Batteries.

Science.gov (United States)

Song, Jiangxuan; Yu, Zhaoxin; Gordin, Mikhail L; Wang, Donghai

2016-02-10

Herein, we report a synthesis of highly crumpled nitrogen-doped graphene sheets with ultrahigh pore volume (5.4 cm(3)/g) via a simple thermally induced expansion strategy in absence of any templates. The wrinkled graphene sheets are interwoven rather than stacked, enabling rich nitrogen-containing active sites. Benefiting from the unique pore structure and nitrogen-doping induced strong polysulfide adsorption ability, lithium-sulfur battery cells using these wrinkled graphene sheets as both sulfur host and interlayer achieved a high capacity of ∼1000 mAh/g and exceptional cycling stability even at high sulfur content (≥80 wt %) and sulfur loading (5 mg sulfur/cm(2)). The high specific capacity together with the high sulfur loading push the areal capacity of sulfur cathodes to ∼5 mAh/cm(2), which is outstanding compared to other recently developed sulfur cathodes and ideal for practical applications.

The effect of calcium phosphate-containing desensitizing agent on ...

African Journals Online (AJOL)

Objective: The aim of this study was to investigate the effect of calcium phosphate containing desensitizing pretreatments on the microtensile bond strength (MTBS) and microleakage of the multimode adhesive agent to dentin. Materials and Methods: In this study, twelve noncarious, freshly extracted human third molar teeth ...

Comparison between female and male of demand of sulfur-containing amino acid of domestic silk worms

International Nuclear Information System (INIS)

Shinbo, Hiroshi; Inokuchi, Tamio

1977-01-01

Comparison of the demand of sulfur-containing amino acid (methionine and cystine) of young domestic silk worms was made between female and male using amino acid diet, and the relation among growth, blood protein and ninhydrin positive substance concentration was discussed. When 3 mg/g of methionine was added to the diet, the growth promotion effect of cystine was hardly recognized for male, while no addition of cystine showed inferior growth for female, however the normal growth was recognized when more than 1 mg/g was added. Accordingly, it is recognized that the female requires more sulfur-containing amino acid than the male. The relationship between the addition of methionine and cystine and the blood protein concentration showed the tendency to conform to the growth approximately. In the effects of blood protein concentration due to diet condition, the difference between female and male were recognized. The relationship between the addition of methionine and cystine in the diet and the ninhydrin positive substance concentration was high in case of the lack of methionine, but the relationship to cystine addition and the difference between female and male were not clear. As a result of measuring 14 CO 2 exhaled from the young worms injected with DL-cystine-1- 14 C, the resolution of cystine in the living body of female was lower than that of male. (Iwakiri, K.)

Labeling of antibodies with a 67Ga-phenolic aminocarboxylic acid chelate. Pt. 1

International Nuclear Information System (INIS)

Schuhmacher, J.; Matys, R.; Hauser, H.; Maier-Borst, W.; Matzku, S.

1986-01-01

As a chelating agent for labeling antibodies (Abs) with metallic radionuclides, a propionic acid substituted ethylenediamine N, N'-di-[(o-hydroxyphenyl) acetic acid] (P-EDDHA), which tighly complexes 67 Ga, was synthetized. The 67 Ga-P-EDDHA chelate was coupled in aqueous solution to IgG at a molar ratio of 1:1 via carbodiimide. The average coupling yield was 15%. A specific activity of 4 mCi/mg IgG could be obtained with commercially supplied 67 Ga. In vitro stability was evaluated in human serum at 37 0 C and showed a half-life of about 120 h for the release of 67 Ga from the labeled Ab during the initial phase of incubation. This in vitro halflife is similar to that measured for 111 In-DTPA labeled Abs. Because of the high stability of the 67 Ga-P-EDDHA chelate, the in vivo formation of radioactive lebeled transferrin by transchelation, as described for 111 In-DTPA labeled Abs, should, however, be reduced by this labeling technique. (orig.)

Bis-phosphonate sequestering agents. Synthesis and preliminary evaluation for in vitro and in vivo uranium(VI) chelation

Energy Technology Data Exchange (ETDEWEB)

Sawicki, M.; Lecercle, D.; Taran, F. [CEA Saclay, IBiTecS, Serv Chim Bioorgan et Marquage, F-91191 Gif Sur Yvette (France); Grillon, G.; Le Gall, B.; Serandour, A.L.; Poncy, J.L. [CEA, DSV, DRR, Lab Radiotoxicol, F-91680 Bruyeres Le Chatel (France); Bailly, T.; Burgada, R.; Lecouvey, M.; Challeix, V. [CNRS, Lab Chim Struct Biomol, UMR 7033, F-93017 Bobigny (France); Leydier, A.; Pellet-Rostaing, S. [Univ Lyon 1, ICBMS, UMR 5246, Lab Catalyse et Synth Organ, F-69622 Villeurbanne (France); Ansoborlo, E. [CEA, DEN, DRCP, CETAMA, VRH Marcoule, F-30207 Bagnols Sur Ceze (France)

2008-07-01

A library of bis-phosphonate-based ligands was prepared using solution-phase parallel synthesis and tested for its uranium-binding properties. With the help of a screening method, based on a chromo-phoric complex displacement procedure, 23 dipodal and tripodal chelates bearing bis-phosphonate chelating functions were found to display very high affinity for the uranyl ion and were selected for evaluation of their in vivo uranyl-removal efficacy. Among them, 11 ligands induced a huge modification of the uranyl biodistribution by deviating the metal from kidney and bones to liver. Among the other ligands, the most potent was the dipodal bis-phosphonate 3C which reduced the retention of uranyl and increased its excretion by around 10% of the injected metal. (authors)

Value of 1.0-M gadolinium chelates: review of preclinical and clinical data on gadobutrol

International Nuclear Information System (INIS)

Tombach, Bernd; Heindel, Walter

2002-01-01

Several preclinical and clinical studies with the first commercially available highly concentrated Gd-chelate gadobutrol (1 mol/l) are reviewed. Physicochemical, pharmacological, and pharmacokinetic properties, safety analysis, as well as experimental and clinical efficacy studies are highlighted in comparison with 0.5-M Gd-chelates. The 1-mol gadobutrol has been proven to be safe in an examined dose range from 0.04 up to 0.5 mmol/kg body weight (b.w.). Even in patients with chronic renal impairment, including hemodialysis, gadobutrol can safely be applied at doses up to 0.3 mmol/kg b.w. For contrast-enhanced MRI in the equilibrium phase, efficacy data analysis shows comparable results to other commercially available extracellular Gd-chelates with lower Gd-concentrations (0.5 M). Studies focused on the potential benefit of a tighter bolus, such as brain perfusion imaging using T2*-effects, document the superiority of a highly concentrated Gd contrast agent. For contrast-enhanced MRA, clinical studies are still ongoing; therefore, the ultimate potential of a more compact bolus, using 1-M Gd-chelates, for contrast-enhanced MRI, has still to be analyzed, especially for time-resolved magnetic resonance angiography. (orig.)

Transformation of sulfur during pyrolysis and hydropyrolysis of coal

Energy Technology Data Exchange (ETDEWEB)

Chen, H.; Li, B.; Yang, J.; Zhang, B. [Chinese Academy of Sciences, Taiyuan (China). Inst. of Coal Chemistry

1998-05-01

It is reported that the transformation of sulfur during pyrolysis (Py) under nitrogen and hydropyrolysis (HyPy) of Chinese Yanzhou high sulfur bituminous coal and Hongmiao lignite was studied in a fixed-bed reactor. The volatile sulfur-containing products were determined by gas chromatography with flame photometric detection. The sulfur in initial coal and char (mainly aliphatic and thiophenic sulfur forms) was quantitatively analyzed using X-ray photoelectron spectroscopy (XPS). The desulfurization yield was calculated by elemental analysis. The main volatile sulfur-containing gas was H{sub 2}S in both Py and HyPy. Both the elemental analysis and XPS results indicated that more sulfur was removed in HyPy than in Py under nitrogen. Thiophenic sulfur can be partially hydrogenated and removed in HyPy. Pyrite can be reduced to a ferrous sulfide completely even as low as 400{degree}C in HyPy while in Py the reduction reaction continues up to 650{degree}C. Mineral matter can not only fix H{sub 2}S produced in Py and HyPy to form higher sulfur content chars but also catalyses the desulfurization reactions to form lower sulfur content tars in HyPy. 24 refs., 8 figs., 4 tabs.

Impact of educational programme regarding chelation therapy on the quality of life for B-thalassemia major children.

Science.gov (United States)

Abu Samra, Omayma; Auda, Wafaa; Kamhawy, Heba; Al-Tonbary, Youssef

2015-06-01

Objectives Thalassemia is the most common genetic disorder in Egypt, with an estimated carrier rate of 9-10%. It is a genetic blood disorder which can be fatal if proper chelation is not received. The introduction of chelating agents capable of removing excessive iron from the body has dramatically increased life expectancy and improved the overall quality of life. The aim of this study was to assess the impact of educational programmes regarding chelation therapy on the quality of life of thalassemic children. Methods The study was carried out at the Mansoura University Children's Hospital in the period between March 2010 and May 2011. It included 173 B-thalassemia children (84 boys and 89 girls) with age ranging between 8-18 years. The researcher used a predesigned interviewing questionnaire to collect data regarding children's knowledge about thalassemia and its management, especially regarding chelation therapy. The paediatric quality-of-life inventory tool (Peds QL 4.0 generic core) was also used to assess the studied children's quality of life. Results There was a significant statistical difference of the studied children's knowledge regarding chelation therapy and their quality of life. Conclusion There was a positive effect of the educational programme in improving children's knowledge score and their quality of life. Application of educational programmes for thalassemic children and their nurses regarding chelation therapy and its importance in preventing thalassemia complications is established.

Manganese(II) chelate contrast media

International Nuclear Information System (INIS)

Rocklage, S.M.; Quay, S.C.

1994-01-01

New chelate forming compounds for use as contrast media in NMR imaging are described. Especially mentioned are manganese(II) ion chelates of N,N' dipyridoxaldiamine, N,N' diacetic acid, and salts and esters thereof. 1 fig

Synthesis and characterization of porous metal oxides and desulfurization studies of sulfur containing compounds

Science.gov (United States)

Garces Trujillo, Hector Fabian

This thesis contains two parts: 1) synthesis and characterization of porous metal oxides that include zinc oxide and a porous mixed-valent manganese oxide with an amorphous structure (AMO) 2) the desulfurization studies for the removal of sulfur compounds. Zinc oxide with different nano-scale morphologies may result in various porosities with different adsorption capabilities. A tunable shape microwave synthesis of ZnO nano-spheres in a co-solvent mixture is presented. The ZnO nano-sphere material is investigated as a desulfurizing sorbent in a fixed bed reactor in the temperature range 200 to 400 °C and compared with ZnO nanorods and platelet-like morphologies. Fresh and sulfided materials were characterized by X-ray diffraction (XRD), BET specific surface area, pore volume, scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (SEM/EDX), Raman spectroscopy, and thermogravimetric analysis (TGA). The tunable shape microwave synthesis of ZnO presents a high sulfur sorption capacity at temperatures as low as 200 °C which accounts for a three and four fold enhancement over the other preparations presented in this work, and reached 76 % of the theoretical sulfur capacity (TSC) at 300 °C. Another ZnO material with a bimodal micro- and mesopore size distribution investigated as a desulfurizing sorbent presents a sorption capacity that reaches 87% of the theoretical value for desulfurization at 400 °C at breakthrough time. A deactivation model that considers the activity of the solid reactant was used to fit the experimental data. Good agreement between the experimental breakthrough curves and the model predictions are obtained. Manganese oxides are a type of metal oxide materials commonly used in catalytic applications. Little is known about the adsorption capabilities for the removal of sulfur compounds. One of these manganese oxides; amorphous manganese oxide (AMO) is highly promising material for low temperature sorption processes. Amorphous

In situ tribochemical sulfurization of molybdenum oxide nanotubes.

Science.gov (United States)

Rodríguez Ripoll, Manel; Tomala, Agnieszka; Gabler, Christoph; DraŽić, Goran; Pirker, Luka; Remškar, Maja

2018-02-15

MoS 2 nanoparticles are typically obtained by high temperature sulfurization of organic and inorganic precursors under a S rich atmosphere and have excellent friction reduction properties. We present a novel approach for making the sulfurization unnecessary for MoO 3 nanotubes during the synthesis process for friction and wear reduction applications while simultaneously achieving a superb tribological performance. To this end, we report the first in situ sulfurization of MoO 3 nanotubes during sliding contact in the presence of sulfur-containing lubricant additives. The sulfurization leads to the tribo-chemical formation of a MoS 2 -rich low-friction tribofilm as verified using Raman spectroscopy and can be achieved both during sliding contact and under extreme pressure conditions. Under sliding contact conditions, MoO 3 nanotubes in synergy with sulfurized olefin polysulfide and pre-formed zinc dialkyl dithiophosphate tribofilms achieve an excellent friction performance. Under these conditions, the tribochemical sulfurization of MoO 3 nanotubes leads to a similar coefficient of friction to the one obtained using a model nanolubricant containing MoS 2 nanotubes. Under extreme pressure conditions, the in situ sulfurization of MoO 3 nanotubes using sulfurized olefin polysulfide results in a superb load carrying capacity capable of outperforming MoS 2 nanotubes. The reason is that while MoO 3 nanotubes are able to continuously sulfurize during sliding contact conditions, MoS 2 nanotubes progressively degrade by oxidation thus losing lubricity.

SYNTHESIS OF SULFUR-BASED WATER TREATMENT AGENT FROM SULFUR DIOXIDE WASTE STREAMS

Energy Technology Data Exchange (ETDEWEB)

Robert C. Brown; Maohong Fan; Adrienne Cooper

2004-11-01

Absorption of sulfur dioxide from a simulated flue gas was investigated for the production of polymeric ferric sulfate (PFS), a highly effective coagulant useful in treatment of drinking water and wastewater. The reaction for PFS synthesis took place near atmospheric pressure and at temperatures of 30-80 C. SO{sub 2} removal efficiencies greater than 90% were achieved, with ferrous iron concentrations in the product less than 0.1%. A factorial analysis of the effect of temperature, oxidant dosage, SO{sub 2} concentration, and gas flow rate on SO{sub 2} removal efficiency was carried out, and statistical analyses are conducted. The solid PFS was also characterized with different methods. Characterization results have shown that PFS possesses both crystalline and non-crystalline structure. The kinetics of reactions among FeSO{sub 4} {center_dot} 7H{sub 2}O, NaHSO{sub 3} and NaClO{sub 3} was investigated. Characterizations of dry PFS synthesized from SO{sub 2} show the PFS possesses amorphous structure, which is desired for it to be a good coagulant in water and wastewater treatment. A series of lab-scale experiments were conducted to evaluate the performance of PFS synthesized from waste sulfur dioxide, ferrous sulfate and sodium chlorate. The performance assessments were based on the comparison of PFS and other conventional and new coagulants for the removal of turbidity and arsenic under different laboratory coagulant conditions. Pilot plant studies were conducted at Des Moines Water Works in Iowa and at the City of Savannah Industrial and Domestic (I&D) Water Treatment Plant in Port Wentworth, Georgia. PFS performances were compared with those of conventional coagulants. The tests in both water treatment plants have shown that PFS is, in general, comparable or better than other coagulants in removal of turbidity and organic substances. The corrosion behavior of polymeric ferric sulfate (PFS) prepared from SO{sub 2} and ferric chloride (FC) were compared. Results

New 68Ga-PhenA bisphosphonates as potential bone imaging agents

International Nuclear Information System (INIS)

Wu, Zehui; Zha, Zhihao; Choi, Seok Rye; Plössl, Karl; Zhu, Lin; Kung, Hank F.

2016-01-01

Introduction: In vivo positron emission tomography (PET) imaging of the bone using [ 68 Ga]bisphosphonates may be a valuable tool for cancer diagnosis and monitoring therapeutic treatment. We have developed new [ 68 Ga]bisphosphonates based on the chelating group, AAZTA (6-[bis(hydroxycarbonyl-methyl)amino]-1,4-bis(hydroxycarbonyl methyl)-6-methylperhydro-1,4-diazepine). Method: Phenoxy derivative of AAZTA (2,2′-(6-(bis(carboxymethyl)amino)-6-((4-(2-carboxyethyl)phenoxy) methyl)-1,4-diazepane-1,4-diyl)diacetic acid), PhenA, 2, containing a bisphosphonate group (PhenA-BPAMD, 3, and PhenA-HBP, 4) was prepared. Labeling of these chelating agents with 68 Ga was evaluated. Results: The ligands reacted rapidly in a sodium acetate buffer with [ 68 Ga]GaCl 3 eluted from a commercially available 68 Ge/ 68 Ga generator (pH 4, > 95% labeling at room temperature in 5 min) to form [ 68 Ga]PhenA-BPAMD, 3, and [ 68 Ga]PhenA-HBP, 4. The improved labeling condition negates the need for further purification. The 68 Ga bisphosphonate biodistribution and autoradiography of bone sections in normal mice after an iv injection showed excellent bone uptake. Conclusion: New 68 Ga labeled bisphosphonates may be useful as in vivo bone imaging agents in conjunction with positron emission tomography (PET).

Diagnostic agents containing albumin and methods for making same

International Nuclear Information System (INIS)

Saklad, E.L.; Layne, W.W.

1981-01-01

This patent specification outlines a method for providing a diagnostic agent for use in radiological testing, comprising the production of an admixture of a source of radionuclide ion (sup(99m)Tc), a reducing agent (source of stannous ions at a pH below 7) and a stabilized, defatted human albumin being sufficiently purified for an aqueous solution not to become cloudy for at least an hour at a pH of 4 or below. Other aspects of the patent provide for a method of producing a radiodiagnostic kit of the above components, packaged in a sealed sterile non-pyrogenic container, and also a method of concentrating sup(99m)Tc in vivo in a target mammalian tissue, by intravenous administration of a mixture of sup(99m)Tc, a reducing agent, and delipidized serum albumin. (U.K.)

Synthesis of microcapsules containing different extractant agents.

Science.gov (United States)

Alcázar, Ángela; Carmona, Manuel; Borreguero, Ana M; de Lucas, Antonio; Rodríguez, Juan F

2015-01-01

Mercury is one of the most toxic pollutants, with high capacity of accumulation in living organism, causing important human health problems. Therefore, the mercury removal from water is an important research goal. In a previous work, an extractant agent [di(2-ethylhexyl)phosphoric acid] was microencapsulated in poly(styrene-co-divinylbenzene) by means of suspension polymerisation using toluene as diluent. In this study, this recipe has been modified changing the toluene by heptane and extended to four additional extractants (trioctylamine, trioctylmethylammonium chloride [TOMAC], tributyl phosphate and trioctylphosphine oxide). The polluting potential of the waste liquid from the process was measured by total organic carbon and chemical oxygen demand analyses. The morphology, particle size and distribution were studied by scanning electron microscopy and low angle laser light scattering. The amount of extractant agent into the microcapsules and the microencapsulation efficiency were determined by thermogravimetric analysis and the mercury removal capacity by equilibrium studies. Microcapsules containing TOMAC demonstrated to be the best material for the mercury removal and retention.

Process for removal of sulfur oxides from hot gases

International Nuclear Information System (INIS)

Bauerle, G. L.; Kohl, A. L.

1984-01-01

A process for the removal of sulfur oxides from two gas streams containing the same. One gas stream is introduced into a spray dryer zone and contacted with a finely dispersed spray of an aqueous medium containing an absorbent for sulfur oxides. The aqueous medium is introduced at a controlled rate so as to provide water to the gas in an amount to produce a cooled product gas having a temperature at least 7 0 C. above its adiabatic saturation temperature and from about 125-300% of the stoichiometric amount of absorbent required to react with the sulfur oxides to be removed from the gas stream. The effluent from the spray dryer zone comprises a gas stream of reduced sulfur oxide content and contains entrained dry particulate reaction products including unreacted absorbent. This gas stream is then introduced into a particulate removal zone from which is withdrawn a gas stream substantially free of particles and having a reduced sulfur oxide content. the dry particulate reaction products are collected and utilized as a source of absorbent for a second aqueous scrubbing medium containing unreacted absorbent for the sulfur oxides. An effluent gas stream is withdrawn from the aqueous scrubbing zone and comprises a water-saturated gas stream of reduced sulfur oxide content and substantially free of particles. The effluent gas streams from the particulate removal zone and the aqueous scrubbing zone are combined in such proportions that the combined gas stream has a temperature above its adiabatic saturation temperature

Preparation and enhanced electrochemical properties of nano-sulfur/poly(pyrrole-co-aniline) cathode material for lithium/sulfur batteries

International Nuclear Information System (INIS)

Qiu Linlin; Zhang Shichao; Zhang Lan; Sun, Mingming; Wang Weikun

2010-01-01

Poly(pyrrole-co-aniline) (PPyA) copolymer nanofibers were prepared by chemical oxidation method with cetyltrimethyl ammonium chloride (CTAC) as template, and the nano-sulfur/poly(pyrrole-co-aniline) (S/PPyA) composite material in lithium batteries was achieved via co-heating the mixture of PPyA and sublimed sulfur at 160 deg. C for 24 h. The component and structure of the materials were characterized by FTIR, Raman, XRD, and SEM. PPyA with nanofiber network structure was employed as a conductive matrix, adsorbing agent and firm reaction chamber for the sulfur cathode materials. The nano-dispersed composite exhibited a specific capacity up to 1285 mAh g -1 in the initial cycle and remained 866 mAh g -1 after 40 cycles.

Removal of Cr(VI) from aqueous solution by flocculant with the capacity of reduction and chelation

International Nuclear Information System (INIS)

Wang, Gang; Chang, Qing; Han, Xiaoting; Zhang, Mingyue

2013-01-01

Highlights: ► We report a novel flocculant with the properties of reduction and chelation for Cr. ► The removal of Cr(VI) by the flocculant depends highly on pH value. ► Some coexisting ions inhibit Cr (VI) removal, but promote total Cr removal. ► Cr and turbidity can be removed simultaneously in the treated wastewater. ► The interaction mechanism is investigated by FTIR and SEM. -- Abstract: A novel agent polyethyleneimine-sodium xanthogenate (PEX) with the multifunction of reduction, chelation, flocculation and precipitation was synthesized by using polyethyleneimine (PEI), carbon disulfide (CS 2 ), and sodium hydroxide (NaOH). The effects of different important parameters, such as pH value, initial Cr(VI) concentration, coexisting ions and turbidity etc., on the removal of chromium from aqueous solution by PEX were investigated in flocculation experiments. The experiments results demonstrated that PEX could efficiently remove Cr(VI) and total Cr (Cr(VI) + Cr(III)) in strongly acidic media. It was proved that the presence of coexisting ions (Na + , Ca 2+ , F − , Cl − , and SO 4 2− ) in the solution had a little influence on the removal of chromium. Furthermore, it was conformed that Cr(VI) ions and turbidity could be simultaneously removed when water samples contained both Cr(VI) ions and turbidity. Finally, the mechanism of interaction between chromium and PEX was further confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results reveal that dithiocarboxylic acid groups on PEX macromolecule play a major role in Cr(VI) reduction and Cr(III) chelation, and the flocs formation is attributed to the interparticle bridging mechanism of PEX

Identification of the iron-sulfur center of spinach ferredoxin-nitrite reductase as a tetranuclear center, and preliminary EPR studies of mechanism.

Science.gov (United States)

Lancaster, J R; Vega, J M; Kamin, H; Orme-Johnson, N R; Orme-Johnson, W H; Krueger, R J; Siegel, L M

1979-02-25

EPR spectroscopic and chemical analyses of spinach nitrite reductase show that the enzyme contains one reducible iron-sulfur center, and one site for binding either cyanide or nitrite, per siroheme. The heme is nearly all in the high spin ferric state in the enzyme as isolated. The extinction coefficient of the enzyme has been revised to E386 = 7.6 X 10(4) cm-1 (M heme)-1. The iron-sulfur center is reduced with difficulty by agents such as reduced methyl viologen (equilibrated with 1 atm of H2 at pH 7.7 in the presence of hydrogenase) or dithionite. Complexation of the enzyme with CO (a known ligand for nitrite reductase heme) markedly increases the reducibility of the iron-sulfur center. New chemical analyses and reinterpretation of previous data show that the enzyme contains 6 mol of iron and 4 mol of acid-labile S2-/mol of siroheme. The EPR spectrum of reduced nitrite reductase in 80% dimethyl sulfoxide establishes clearly that the enzyme contains a tetranuclear iron-sulfur (Fe4S4) center. The ferriheme and Fe4S4 centers are reduced at similar rates (k = 3 to 4 s-1) by dithionite. The dithionite-reduced Fe4S4 center is rapidly (k = 100 s-1) reoxidized by nitrite. These results indicate a role for the Fe4S4 center in catalysis.

Dynamics of a Novel Class of Polymers: Polymerized Sulfur

Science.gov (United States)

Masser, Kevin; Kim, Jenny; Oleshko, Vladimir; Griebel, Jared; Chung, Woo; Simmons, Adam; Pyun, Jeff; Soles, Christopher

2013-03-01

In this study we investigate the dynamics of a new type of polymer, consisting mainly of sulfur. Room-temperature stable polymerized sulfur samples were prepared by crosslinking the well-known living sulfur polymers formed at elevated temperatures by the addition of a crosslinking agent. This reverse vulcanization process was used to create a series of samples with different amounts of crosslinking agent. These polymers show great promise for use in advanced batteries as cathode materials. Each system exhibits a glassy-state beta relaxation, with the intensity of this relaxation proportional to the crosslinking content. A dynamic glass transition is also observed for each system, and the glass transition temperature/segmental relaxation moves to higher temperatures with increased crosslink content as is typically observed in crosslinked systems. As is typical of polymers, ion motion in these systems is closely coupled to the backbone motion of the host polymer. National Research Council Postdoctoral Fellowship

Photochemical modification of diamond powder with sulfur functionalities and its behavior on gold surfaces

International Nuclear Information System (INIS)

Nakamura, T; Ohana, T; Hagiwara, Y; Tsubota, T

2010-01-01

A useful method of modifying the surface of diamond powders with sulfur-containing functionalities was developed by the use of the photolysis of elemental sulfur. The introduction of sulfur-containing functional groups on the diamond surfaces was confirmed by means of XPS, DRIFT and mass spectroscopy analyses. The sulfur-modified diamond powders exhibited surface-attachment behavior to gold surfaces through the sulfur-containing linkage. In brief, exposure of the modified diamond powders to gold colloids resulted in gold nanoparticles being attached to the diamond powders. Treatment of the modified diamond powders with gold thin film on Si substrate afforded alignment of surface-attached diamond powders through sulfur linkages by self-assembly.

Sulfur isotope in nature. Determination of sulfur isotope ratios in coal and petroleum by mass spectrometry

International Nuclear Information System (INIS)

Derda, M.

1999-01-01

Elementary sulfur or in chemical compounds is one of the elements widespread in the earth's crust and biosphere. Its participation in earth's crust amounts to 0.26 % by weight. Measurement of isotope composition of natural samples can deliver many information about origin, creation and transformation ranges of rocks and minerals. Sulfur isotope ratio contained in minerals is variable and for this reason investigation of isotope sulfur composition can deliver useful information about the geochemistry of each component. Therefore in the investigated sample it is necessary to determine not only the content of sulfur but also the isotope composition of each component. Differentiation of contents of sulfur-34 in natural sulfur compounds can reach up to 110 per mile. So large divergences can be explained by a kinetic effect or by bacterial reduction of sulphates. In this report a wide review of the results of investigations of isotope sulfur compositions in coal and petroleum are presented as well as the methods for the preparation of samples for mass spectrometry analysis are proposed. (author)

Removal of cadmium from fish sauce using chelate resin.

Science.gov (United States)

Sasaki, Tetsuya; Araki, Ryohei; Michihata, Toshihide; Kozawa, Miyuki; Tokuda, Koji; Koyanagi, Takashi; Enomoto, Toshiki

2015-04-15

Fish sauce that is prepared from squid organs contains cadmium (Cd), which may be present at hazardous concentrations. Cd molecules are predominantly protein bound in freshly manufactured fish sauce, but are present in a liberated form in air-exposed fish sauce. In the present study, we developed a new method for removing both Cd forms from fish sauce using chelate resin and a previously reported tannin treatment. Sixteen-fold decreases in Cd concentrations were observed (0.78-0.05 mg/100 mL) following the removal of liberated Cd using chelate resin treatment, and the removal of protein-bound Cd using tannin treatment. Major nutritional components of fish sauce were maintained, including free amino acids and peptides, and angiotensin I-converting enzyme inhibitory and antioxidant activities. Copyright © 2014 Elsevier Ltd. All rights reserved.

Iron chelates: a challenge to chemists and Moessbauer spectroscopists

Energy Technology Data Exchange (ETDEWEB)

Homonnay, Z., E-mail: homonnay@chem.elte.hu; Szilagyi, P. A.; Vertes, A. [Eoetvoes Lorand University, Laboratory of Nuclear Chemistry, Institute of Chemistry (Hungary); Kuzmann, E. [Hungarian Academy of Sciences, Department of Nuclear Chemistry, Chemical Research Center (Hungary); Sharma, V. K. [Florida Institute of Technology (United States); Molnar, G.; Bousseksou, A. [CNRS UPR-8241, Laboratoire de Chimie de Coordination (France); Greneche, J.-M. [Universite du Maine, Laboratoire de Physique de l' Etat Condense, CNRS UMR 6087 (France); Brausam, A.; Meier, R.; Eldik, R. van [University of Erlangen-Nuernberg, Institute for Inorganic Chemistry (Germany)

2008-02-15

The speciation of iron in aqueous solutions containing Fe{sup 3+} and selected chelates such as EDTA, EDDA, CDTA and HEDTA has been studied using transmission {sup 57}Fe Moessbauer spectrometry in frozen solutions. The protonation of various complexes as well as binuclear complex formation could be detected as a function of pH. Autoreduction of Fe{sup 3+} to Fe{sup 2+} was observed in several cases. Reaction with hydrogen peroxide proved to be rather different for the four ligands, while the dihapto complex [XFe({eta}{sup 2}-O{sub 2})]{sup 3-} had surprisingly identical Moessbauer parameters for X = EDTA, CDTA or HEDTA. Paramagnetic spin relaxation observed in the Moessbauer spectra was found to be strongly influenced by the identity of the chelating ligand, despite the basically spin-spin origin of the phenomenon.

Synthesis and characterisation of 8-hydroxyquinoline-bovine serum albumin conjugates as metal ion chelating proteins

International Nuclear Information System (INIS)

Giraudi, G.; Baggiani, C.; Giovannoli, C.; Marletto, C.; Vanni, A.

1999-01-01

A derivative of 8-hydroxyquinoline (8-quinolinol, oxine) with a linking bridge containing a carboxylic group was covalently coupled to bovine serum albumin by the N-hydroxysuccinimide method to obtain stable monomeric conjugates with oxine to protein mole ratios up to 37. These conjugates were characterised spectrophotometrically and their complexation properties were confirmed by spectral analysis with and without the addition of Al(III), Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Ni(II), Pb(II), V(IV), U(VI) and Zn(II) ions added. The maximum number of ions bound by these chelating proteins was determined spectrophotometrically by titration with metal ions at pH 6.0. The conjugates with a substitution ratio (moles of 8-hydroxyquinoline bound/mole of albumin) less than about 8 showed 1:1 binding with metal ions, while conjugates with higher substitution ratios were able to complex with 2:1 ratio of 8-hydroxyquinoline to metal ion. Association and dissociation kinetics of complexation with copper(II) ions showed a complex mechanism. The spectral and binding properties of these metal ion-binding proteins confirm that the coupling of the 8-hydroxyquinoline derivative to bovine serum albumin gives stable, water soluble, macromolecular chelating agents that retain the complexing ability of the original ligand. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Method of making a sodium sulfur battery

Science.gov (United States)

Elkins, Perry E.

1981-01-01

A method of making a portion of a sodium sulfur battery is disclosed. The battery portion made is a portion of the container which defines the volume for the cathodic reactant materials which are sulfur and sodium polysulfide materials. The container portion is defined by an outer metal casing with a graphite liner contained therein, the graphite liner having a coating on its internal diameter for sealing off the porosity thereof. The steel outer container and graphite pipe are united by a method which insures that at the operating temperature of the battery, relatively low electrical resistance exists between the two materials because they are in intimate contact with one another.

Efficacy of a novel chelator BPCBG for removing uranium and protecting against uranium-induced renal cell damage in rats and HK-2 cells

Energy Technology Data Exchange (ETDEWEB)

Bao, Yizhong; Wang, Dan [Institute of Radiation Medicine, Fudan University, Shanghai 200032 (China); Li, Zhiming [Department of Chemistry, Fudan University, Shanghai 200433 (China); Hu, Yuxing; Xu, Aihong [Institute of Radiation Medicine, Fudan University, Shanghai 200032 (China); Wang, Quanrui [Department of Chemistry, Fudan University, Shanghai 200433 (China); Shao, Chunlin [Institute of Radiation Medicine, Fudan University, Shanghai 200032 (China); Chen, Honghong, E-mail: hhchen@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, Shanghai 200032 (China)

2013-05-15

Chelation therapy is a known effective method to increase the excretion of U(VI) from the body. Until now, no any uranium chelator has been approved for emergency medical use worldwide. The present study aimed to evaluate the efficacy of new ligand BPCBG containing two catechol groups and two aminocarboxylic acid groups in decorporation of U(VI) and protection against acute U(VI) nephrotoxicity in rats, and further explored the detoxification mechanism of BPCBG for U(VI)-induced nephrotoxicity in HK-2 cells with comparison to DTPA-CaNa{sub 3}. Chelating agents were administered at various times before or after injections of U(VI) in rats. The U(VI) levels in urine, kidneys and femurs were measured 24 h after U(VI) injections. Histopathological changes in the kidney and serum urea and creatinine and urine protein were examined. After treatment of U(VI)-exposed HK-2 cells with chelating agent, the intracellular U(VI) contents, formation of micronuclei, lactate dehydrogenase (LDH) activity and production of reactive oxygen species (ROS) were assessed. It was found that prompt, advanced or delayed injections of BPCBG effectively increased 24 h-urinary U(VI) excretion and decreased the levels of U(VI) in kidney and bone. Meanwhile, BPCBG injection obviously reduced the severity of the U(VI)-induced histological alterations in the kidney, which was in parallel with the amelioration noted in serum indicators, urea and creatinine, and urine protein of U(VI) nephrotoxicity. In U(VI)-exposed HK-2 cells, immediate and delayed treatment with BPCBG significantly decreased the formation of micronuclei and LDH release by inhibiting the cellular U(VI) intake, promoting the intracellular U(VI) release and inhibiting the production of intracellular ROS. Our data suggest that BPCBG is a novel bi-functional U(VI) decorporation agent with a better efficacy than DTPA-CaNa{sub 3}. - Highlights: ► BPCBG accelerated the urine U(VI) excretion and reduced the tissues U(VI) in rats. �

Microencapsulation of self-healing agents containing a fluorescent dye

Directory of Open Access Journals (Sweden)

J. K. Lee

2013-01-01

Full Text Available Two different self-healing agent candidates, endo-dicyclopentadiene (endo-DCPD and 5-ethylidene-2-norbornene (ENB, containing a fluorescent dye surrounded by a melamine–urea–formaldehyde (MUF shell were microencapsulated by in-situ polymerization and the resulting microcapsules were characterized in this work. The microcapsules showed a narrow size distribution with a spherical shape and rough outer and smooth inner surfaces for both healing agent systems. Shell thicknesses of the microcapsules were ~880±80 nm for endo-DCPD and ~620±60 nm for ENB. The incorporation of a fluorescent dye as tracer into self-healing agents did not disturb the formation of microcapsules. The release of self-healing liquid into the induced crack from ruptured microcapsules in an epoxy coating layer was observed using a fluorescence microscopy. The use of a fluorescent dye is very effective in the observation of a damage site.

Relationship among chelator adherence, change in chelators, and quality of life in thalassemia.

Science.gov (United States)

Trachtenberg, Felicia L; Gerstenberger, Eric; Xu, Yan; Mednick, Lauren; Sobota, Amy; Ware, Hannah; Thompson, Alexis A; Neufeld, Ellis J; Yamashita, Robert

2014-10-01

Thalassemia, a chronic blood disease, necessitates life-long adherence to blood transfusions and chelation therapy to reduce iron overload. We examine stability of health-related quality of life (HRQOL) in thalassemia and adherence to chelation therapy over time, especially after changes in chelator choice. Thalassemia Longitudinal Cohort participants in the USA, UK, and Canada completed the SF-36v2 (ages 14+) and the PF-28 CHQ (parents of children health status) at baseline who made a single change in chelator, but declined among participants with multiple changes and/or high iron burden (worse health status). Mental health improved among participants with lower iron burden, but iron overload was negatively associated with social functioning. Adherence did not significantly change over follow-up except for an increase after a change from deferoxamine (DFO) infusion to oral deferasirox (p = 0.03). Predictors of lower adherence for adults/adolescents at follow-up included side effects, smoking, younger age, problems preparing DFO, increased number of days per week DFO prescribed, and lower physical quality of life . Strategies to balance medical needs with family, work, and personal life may assist in adherence.

High temperature dissolution of ferrites, chromites and bonaccordite in chelating media

Energy Technology Data Exchange (ETDEWEB)

Sathyaseelan, V.S.; Subramanian, H.; Anupkumar, B.; Rufus, A.L.; Velmurugan, S.; Narasimhan, S.V., E-mail: snv@igcar.gov.in [BARC Facilities, Water and Steam Chemistry Div., Tamilnadu (India)

2010-07-01

by the reagents used in chemical decontamination processes. Sample of bonaccordite was prepared by solid state route by heating stoichiometric mixtures of Hematite, Nickel Oxide and Boric acid at 900{sub o}C for 24 Hours. The phase purity of Bonaccordite formed was confirmed by XRD and Laser Raman Spectroscopy. Studies carried out in the Teflon lined autoclave indicated that boron and zinc containing oxides/ ferrites can be dissolved more easily at elevated temperatures (>140{sub o}C) as compared to normal temperatures (80 - 100{sub o}C). The effect of variation of temperature, concentration of chelating agent, presence of reducing agents has also been studied. High temperature corrosion study of carbon steel (CS) and stainless steel in all the above chelating medium in the presence and the absence of reductants has been carried out. About 60% reduction in corrosion rate was observed for CS in NTA medium in the presence of N{sub 2}H{sub 4} at 160{sup o}C and at pH 6.5. However, at the same temperature and pH, in the absence of N{sub 2}H{sub 4}, corrosion rate of CS was decreased drastically. With increase in temperature, dissolution rate of chromium oxide also increased considerably. The effectiveness of high temperature process was substantiated by using oxide covered specimen prepared under simulated BWR water chemistry conditions. (author)

Chelation technology: a promising green approach for resource management and waste minimization.

Science.gov (United States)

Chauhan, Garima; Pant, K K; Nigam, K D P

2015-01-01

Green chemical engineering recognises the concept of developing innovative environmentally benign technologies to protect human health and ecosystems. In order to explore this concept for minimizing industrial waste and for reducing the environmental impact of hazardous chemicals, new greener approaches need to be adopted for the extraction of heavy metals from industrial waste. In this review, a range of conventional processes and new green approaches employed for metal extraction are discussed in brief. Chelation technology, a modern research trend, has shown its potential to develop sustainable technology for metal extraction from various metal-contaminated sites. However, the interaction mechanism of ligands with metals and the ecotoxicological risk associated with the increased bioavailability of heavy metals due to the formation of metal-chelant complexes is still not sufficiently explicated in the literature. Therefore, a need was felt to provide a comprehensive state-of-the-art review of all aspects associated with chelation technology to promote this process as a green chemical engineering approach. This article elucidates the mechanism and thermodynamics associated with metal-ligand complexation in order to have a better understanding of the metal extraction process. The effects of various process parameters on the formation and stability of complexes have been elaborately discussed with respect to optimizing the chelation efficiency. The non-biodegradable attribute of ligands is another important aspect which is currently of concern. Therefore, biotechnological approaches and computational tools have been assessed in this review to illustrate the possibility of ligand degradation, which will help the readers to look for new environmentally safe mobilizing agents. In addition, emerging trends and opportunities in the field of chelation technology have been summarized and the diverse applicability of chelation technology in metal extraction from

Thermodynamic stability and relaxation studies of small, triaza-macrocyclic Mn(II) chelates.

Science.gov (United States)

de Sá, Arsénio; Bonnet, Célia S; Geraldes, Carlos F G C; Tóth, Éva; Ferreira, Paula M T; André, João P

2013-04-07

Due to its favorable relaxometric properties, Mn(2+) is an appealing metal ion for magnetic resonance imaging (MRI) contrast agents. This paper reports the synthesis and characterization of three new triazadicarboxylate-type ligands and their Mn(2+) chelates (NODAHep, 1,4,7-triazacyclononane-1,4-diacetate-7-heptanil; NODABA, 1,4,7-triazacyclononane-1,4-diacetate-7-benzoic acid; and NODAHA, 1,4,7-triazacyclononane-1,4-diacetate-7-hexanoic acid). The protonation constants of the ligands and the stability constants of the chelates formed with Mn(2+) and the endogenous Zn(2+) ion have been determined by potentiometry. In overall, the thermodynamic stability of the chelates is lower than that of the corresponding NOTA analogues (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetate), consistent with the decreased number of coordinating carboxylate groups. Variable temperature (1)H NMRD and (17)O NMR measurements have been performed on the paramagnetic chelates to provide information on the water exchange rates and the rotational dynamics. The values of the (17)O chemical shifts are consistent with the presence of one water molecule in the first coordination sphere of Mn(2+). The three complexes are in the slow to intermediate regime for the water exchange rate, and they all display relatively high rotational correlation times, which explain the relaxivity values between 4.7 and 5.8 mM(-1) s(-1) (20 MHz and 298 K). These relaxivities are higher than expected for Mn(2+) chelates of such size and comparable to those of small monohydrated Gd(3+) complexes. The amphiphilic [Mn(NODAHep)] forms micelles above 22 mM (its critical micellar concentration was determined by relaxometry and fluorescence), and interacts with HSA via its alkylic carbon chain providing a 60% relaxivity increase at 20 MHz due to a longer tumbling time.

Preparation and electrochemical performance of sulfur-alumina cathode material for lithium-sulfur batteries

International Nuclear Information System (INIS)

Dong, Kang; Wang, Shengping; Zhang, Hanyu; Wu, Jinping

2013-01-01

Highlights: ► Micron-sized alumina was synthesized as adsorbent for lithium-sulfur batteries. ► Sulfur-alumina material was synthesized via crystallizing nucleation. ► The Al 2 O 3 can provide surface area for the deposition of Li 2 S and Li 2 S 2 . ► The discharge capacity of the battery is improved during the first several cycles. - Abstract: Nano-sized sulfur particles exhibiting good adhesion with conducting acetylene black and alumina composite materials were synthesized by means of an evaporated solvent and a concentrated crystallization method for use as the cathodes of lithium-sulfur batteries. The composites were characterized and examined by X-ray diffraction, environmental scanning electron microscopy and electrochemical methods, such as cyclic voltammetry, electrical impedance spectroscopy and charge–discharge tests. Micron-sized flaky alumina was employed as an adsorbent for the cathode material. The initial discharge capacity of the cathode with the added alumina was 1171 mAh g −1 , and the remaining capacity was 585 mAh g −1 after 50 cycles at 0.25 mA cm −2 . Compared with bare sulfur electrodes, the electrodes containing alumina showed an obviously superior cycle performance, confirming that alumina can contribute to reducing the dissolution of polysulfides into electrolytes during the sulfur charge–discharge process

Characterization of amorphous yttria layers deposited by aqueous solutions of Y-chelate alkoxides complex

Science.gov (United States)

Kim, Young-Soon; Lee, Yu-Ri; Kim, Byeong-Joo; Lee, Jae-Hun; Moon, Seung-Hyun; Lee, Hunju

2015-01-01

Crack-free amorphous yttria layers were deposited by dip coating in solutions of different Y-chelate alkoxides complex. Three Y-chelate solutions of different concentrations were prepared using yttrium acetate tetrahydrate, yttrium stearic acid as Y source materials. PEG, diethanolamine were used as chelating agents, while ethanol, methanol and tetradecane were used as solvent. Three different combinations of chelating and solvents were used to prepare solutions for Y2O3 dip coating on SUS, electropolished and non-electropolished Hastelloy C-276 substrates. The thickness of the films was varied by changing the number of dipping cycles. At an optimized condition, the substrate surface roughness (rms) value was reduced from ∼50 nm to ∼1 nm over a 10 × 10 μm2 area. After Y2O3 deposition, MgO was deposited using ion-beam assisted deposition (IBAD), then LaMnO3 (LMO) was deposited using sputtering and GdBCO was deposited using reactive co-evaporation by deposition and reaction (RCE-DR). Detailed X-ray study indicates that LMO/MgO/Y2O3 and GdBCO/LMO/MgO/Y2O3 stack films have good out-of-plane and in-plane textures with strong c-axis alignment. The critical current (Ic) of GdBCO/LMO/MgO/Y2O3 multilayer structure varied from 190 to 420 A/cm with different solutions, when measured at 77 K. These results demonstrated that amorphous yttria can be easily deposited by dip coating using Y-chelates complex as a diffusion barrier and nucleation layer.

Synthesis and Characterization of 4-Benzyloxybenzaldehyde-4-methyl-3-thiosemicarbazone (Containing Sulphur and Nitrogen Donor Atoms and Its Cd(II Complex

Directory of Open Access Journals (Sweden)

Lakshmi Narayana Suvarapu

2015-12-01

Full Text Available A chelating agent, 4-benzyloxybenzaldehyde-4-methyl-3-thiosemicarbazone (BBMTSC, containing sulphur and nitrogen donor atoms was synthesized and applied as a ligand for the chelation of Cd(II. Both the BBMTSC and its Cd(II complex were characterized by elemental analysis, UV-Vis absorption spectra, Fourier transform infrared spectroscopy (FT-IR, mass spectra, nuclear magnetic resonance spectroscopy (NMR, X-ray powder diffraction (XRD, and field emission scanning electron microscopy (FESEM. The FTIR spectra confirmed the formation of both BBMTSC and its Cd(II complex. XRD revealed the polycrystalline nature of the synthesized compounds. BBMTSC exhibited a flake-like micro-rod morphology, whereas the Cd(II complex had a flower-like nanorod structure.

Comparison of DOTA and NODAGA as chelators for (64)Cu-labeled immunoconjugates.

Science.gov (United States)

Ghosh, Sukhen C; Pinkston, Kenneth L; Robinson, Holly; Harvey, Barrett R; Wilganowski, Nathaniel; Gore, Karen; Sevick-Muraca, Eva M; Azhdarinia, Ali

2015-02-01

Bifunctional chelators have been shown to impact the biodistribution of monoclonal antibody (mAb)-based imaging agents. Recently, radiolabeled 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA)-peptide complexes have demonstrated improved in vivo stability and performance compared to their 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) counterparts. Here, we investigated if similar utility could be achieved with mAbs and compared (64)Cu-labeled DOTA and NODAGA-immunoconjugates for the detection of epithelial cell adhesion molecule (EpCAM) in a prostate cancer model. DOTA and NODAGA-immunoconjugates of an EpCAM targeting mAb (mAb7) were synthesized and radiolabeled with (64)Cu (DOTA: 40°C for 1hr; NODAGA: 25°C for 1hr). The average number of chelators per mAb was quantified by isotopic dilution, and the biological activity of the immunoconjugates was evaluated by flow cytometry and ELISA. Radioligand assays were performed to compare cellular uptake and determine the dissociation constant (Kd) and maximum number of binding sites (Bmax) for the immunoconjugates using DsRed-transfected PC3-cells. A PC3-DsRed xenograft tumor model was established in nude mice and used to perform biodistribution studies to compare organ uptake and pharmacokinetics. (64)Cu-DOTA-mAb7 and (64)Cu-NODAGA-mAb7 were prepared with chelator/protein ratios of 2-3 and obtained in comparable radiochemical yields ranging from 59 to 71%. Similar immunoreactivity was observed with both agents, and mock labeling studies indicated that incubation at room temperature or 40°C did not affect potency. (64)Cu-NODAGA-mAb7 demonstrated higher in vitro cellular uptake while (64)Cu-DOTA-mAb7 had higher Kd and Bmax values. From the biodistribution data, we found similar tumor uptake (13.44±1.21%ID/g and 13.24±4.86%ID/g for (64)Cu-DOTA-mAb7 and (64)Cu-NODAGA-mAb7, respectively) for both agents at 24hr, although normal prostate tissue was significantly lower for (64)Cu-NODAGA-mAb7

UV absorption cross-sections of selected sulfur-containing compounds at temperatures up to 500°C

DEFF Research Database (Denmark)

Grosch, Helge; Fateev, Alexander; Clausen, Sønnik

2015-01-01

The temperature dependence of the ultraviolet absorption cross-sections of three different sulfur containing compounds, hydrogen sulfide (H2S), carbon disulfide (CS2) and carbonyl sulfide (OCS), are presented between 200nm and 360nm at a resolution of 0.018nm. The absorption cross-sections for each...... compound are initially compared with those available in the literature, followed by the discussion of the measurements and their spectral features at three temperatures up to 500°C/773K. Uncertainties in the measured absorption cross-sections are also addressed....

Magnetic Resonance Imaging Contrast Agents: A Review of Literature

Directory of Open Access Journals (Sweden)

Zahra Sahraei

2015-10-01

Full Text Available  Magnetic Resonance Imaging (MRI contrast agents most commonly agents used in diagnosing different diseases. Several agents have been ever introduced with different peculiar characteristics. They vary in potency, adverse reaction and other specification, so it is important to select the proper agent in different situations. We conducted a systematic literature search in MEDLINE/PUBMED, Web of Science (ISI, Scopus,Google Scholar by using keywords "gadolinium" and "MRI contrast Medias", "Gadofosvest", "Gadobenate" and "Gadoxetate". The most frequent contrast media agents made based on gadolinium (Gd. These are divided into two categories based on the structure of their chelating parts, linear agents and macrocyclic agents. All characteristics of contrast media factors, including efficiency, kinetic properties, stability, side effects and the rate of resolution are directly related to the structure of chelating part of that formulation.In vitro data has shown that the macrocyclic compounds are the most stable Gd-CA as they do not bind to serum proteins, they all possess similar and relatively low relaxivity and the prevalence of Nephrogenic Systemic Fibrosis (NSF has decreased by increasing the use of macrocyclic agents in recent years. No cases of NSF have been recorded after the administration of any of the high-relaxivity protein interacting agents, the vascular imaging agent gadofosveset trisodium (Ablavar, the hepatic imaging agent gadoxetate meglumine (Eovist, and the multipurpose agent gadobenate dimeglumine (MultiHance. In pregnancy and lactating women, stable macrocyclic agent is recommended.

Synthesis and evaluation of a class of 1,4,7-triazacyclononane derivatives as iron depletion antitumor agents.

Science.gov (United States)

Wang, Sheng; Gai, Yongkang; Zhang, Shasha; Ke, Lei; Ma, Xiang; Xiang, Guangya

2018-01-15

Iron depletion has been confirmed as an efficient strategy for cancer treatment. In the current study, a series of 1,4,7-triazacyclononane derivatives HE-NO2A, HP-NO2A and NE2P2A, as well as the bifunctional chelators p-NO 2 -PhPr-NE3TA and p-NH 2 -PhPr-NE3TA were synthesized and evaluated as iron-depleting agents for the potential anti-cancer therapy against human hepatocellular carcinoma. The cytotoxicity of these chelators was measured using hepatocellular cancer cells and compared with the clinically available iron depletion agent DFO and the universal metal chelator DTPA. All these 1,4,7-triazacyclononane-based chelators exhibited much stronger antiproliferative activity than DFO and DTPA. Among them, chelators with phenylpropyl side chains, represented by p-NO 2 -PhPr-NE3TA and p-NH 2 -PhPr-NE3TA, displayed the highest antiproliferative activity against HepG2 cells. Hence, these compounds are attractive candidates for the advanced study as iron depletion agents for the potential anti-cancer therapy, and could be further in conjugation with a targeting moiety for the future development in targeted iron depletion therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environment-Friendly Control of Pear Scab and Rust Using Lime Sulfur

Directory of Open Access Journals (Sweden)

Ju Hoon Cha

2018-03-01

Full Text Available Pear scab and rust are the major diseases causing severe epidemics in organic cultivation of pear trees. Incidences of pear scab and rust were compared in organically managed plots and conventionally managed plots to obtain optimum application schedule of environment-friendly control agents in organically managed plots. Organically cultural practice with 10 time-applications of lime sulfur and Bordeaux mixture showed higher than 40% of control efficacies of pear scab and rust compared to conventionally cultural practice. Organically cultural practice with 8 time-applications of lime sulfur considering weather condition showed higher than 30% of control efficacies of pear scab compared to conventionally cultural practice. The results suggest that proper application of environment-friendly control agents such as lime sulfur considering weather condition will enable effective control of the major diseases for organic cultivation of pear.

Capsaicinoids, chloropicrin and sulfur mustard: Possibilities for exposure biomarkers

Directory of Open Access Journals (Sweden)

Maija Pesonen

2010-12-01

Full Text Available Incapacitating and irritating agents produce temporary disability persisting for hours to days after the exposure. One can be exposed to these agents occupationally in industrial or other working environments. Also general public can be exposed in special circumstances, like industrial accidents or riots. Incapacitating and irritating agents discussed in this review are chloropicrin and capsaicinoids. In addition, we include sulfur mustard, which is an old chemical warfare agent and known to cause severe long-lasting injuries or even death. Chloropicrin that was used as a warfare agent in the World War I is currently used mainly as a pesticide. Capsaicinoids, components of hot pepper plants, are used by police and other law enforcement personnel as riot control agents. Toxicity of these chemicals is associated particularly with the respiratory tract, eyes and skin. Their acute effects are relatively well known but the knowledge of putative long-term effects is almost non-existent. Also, mechanisms of effects at cellular level are not fully understood. There is a need for further research to get better idea of health risks, particularly of long-term and low-level exposures to these chemicals. For this, exposure biomarkers are essential. Validated exposure biomarkers for capsaicinoids, chloropicrin and sulfur mustard do not exist so far. Metabolites and macromolecular adducts have been suggested biomarkers for sulfur mustard and these can already be measured qualitatively, but quantitative biomarkers await further development and validation. The purpose of this review is, based on the existing mechanistic and toxicokinetic information, to shed light on the possibilities for developing biomarkers for exposure biomonitoring of these compounds. It is also of interest to find ideas for early effect biomarkers considering the need for studies on subchronic and chronic toxicity.

The Iron Chelator, Dp44mT, Effectively Inhibits Human Oral Squamous Cell Carcinoma Cell Growth in Vitro and in Vivo

Directory of Open Access Journals (Sweden)

Jehn-Chuan Lee

2016-08-01

Full Text Available Oral squamous cell carcinoma (OSCC is a common malignancy with a growing worldwide incidence and prevalence. The N-myc downstream regulated gene (NDRG family of NDRG1, 2, 3, and mammary serine protease inhibitor (Maspin gene are well-known modulators in the neoplasia process. Current research has considered iron chelators as new anti-cancer agents; however, the anticancer activities of iron chelators and their target genes in OSCC have not been well investigated. We showed that iron chelators (Dp44mT, desferrioxamine (DFO, and deferasirox all significantly inhibit SAS cell growth. Flow cytometry further indicated that Dp44mT inhibition of SAS cells growth was partly due to induction of G1 cell cycle arrest. Iron chelators enhanced expressions of NDRG1 and NDRG3 while repressing cyclin D1 expression in OSCC cells. The in vivo antitumor effect on OSCC and safety of Dp44mT were further confirmed through a xenograft animal model. The Dp44mT treatment also increased Maspin protein levels in SAS and OECM-1 cells. NDRG3 knockdown enhanced the growth of OECM-1 cells in vitro and in vivo. Our results indicated that NDRG3 is a tumor suppressor gene in OSCC cells, and Dp44mT could be a promising therapeutic agent for OSCC treatment.

Digestion of Bangka monazite with sulfuric acid

International Nuclear Information System (INIS)

Riesna Prassanti

2012-01-01

Technology of Bangka monazite processing with alkaline method has been mastered by PPGN BATAN with the product in the form of RE (Rare Earth) which is contain U < 2 ppm and Th 12 - 16 ppm. Hence, as comparator, the research of Bangka monazite processing with acid method using sulfuric acid has been done. The aim of this research is to obtain the optimal condition of Bangka monazite's digestion using sulfuric acid so that all elements contained in the monazite that are U, Th, RE, PO 4 dissolved as much as possible. The research parameter's arc monazite particle's size, sulfuric acid consumption (weight ratio of monazite ore : sulfuric acid), digestion temperature, digestion time and consumption of wash water. The results showed that the optimal conditions of digestion are 250+ 325 mesh of monazite particle's size, 1 : 2.5 of weight ratio of monazite ore: sulfuric acid, 190°C of digestion temperature, 3 hours of digestion time and 8 times of weight monazite's feed of wash water with the recovery of digested U = 99.90 %, Th = 99.44 %, RE = 98.64 % and PO 4 = 99.88 %. (author)

Experimental approbation of a new ultrosound contrast agent based on sulfur geksafluoride in diagnostics of focal liver lesions of inflammatory genesis

Directory of Open Access Journals (Sweden)

S. V. Fomina

2017-01-01

Full Text Available Purpose of the study. Experimental approbation of a new domestic ultrasound contrast agent (UCA based on sulfur hexafluoride in the diagnosis of focal liver lesions of inflammatory genesis.Materials and methods. The investigated ultrasound contrast agent (UCA was a heterogeneous gas-liquid system consisting of micro bubbles of a sparingly soluble gas of sulfur hexafluoride (SF6 surrounded by a flexible mobile membrane of surfactants. Experimental work was carried out on rabbits. The study group included rabbits of males and females with focal liver lesion of inflammatory genesis (n = 12 weighing 1500- 1700 g. UCA was administered to animals in the ear vein. Focal lesions of the liver in animals were created in the experimental laboratory conditions. 14 days after the operation, all animals were subjected to ultrasound examination of the surgical intervention zones by using the Toshiba Aplio 400 scanners (Japan with a 3,5–8 MHz convection sensor. In a natural study, the size, structure and echogenicity of the focus were assessed, the degree of vascularization, the evenness and clarity of the contours were determined. When performing post contrast ultrasound, the time of the onset of contrast enhancement, the total duration of contrast, the changes in the contrast enhancement of the focus in different phases of the study were measured, the dimensions of the focus were measured, and the evenness and acuity of contours were measured. For histological examination, liver fragments and lungs were used. 

Effects of lead and chelators on growth, photosynthetic activity and Pb uptake in Sesbania drummondii grown in soil

International Nuclear Information System (INIS)

Ruley, Adam T.; Sharma, Nilesh C.; Sahi, Shivendra V.; Singh, Shree R.; Sajwan, Kenneth S.

2006-01-01

Effects of lead (Pb) and chelators, such as EDTA, HEDTA, DTPA, NTA and citric acid, were studied to evaluate the growth potential of Sesbania drummondii in soils contaminated with high concentrations of Pb. S. drummondii seedlings were grown in soil containing 7.5 g Pb(NO 3 ) 2 and 0-10 mmol chelators/kg soil for a period of 2 and 4 weeks and assessed for growth profile (length of root and shoot), chlorophyll a fluorescence kinetics (F v /F m and F v /F o ) and Pb accumulations in root and shoot. Growth of plants in the presence of Pb + chelators was significantly higher (P v /F m and F v /F o values of treated seedlings remained unaffected, indicating normal photosynthetic efficiency and strength of plants in the presence of chelators. On application of chelators, while root uptake of Pb increased four-five folds, shoot accumulations increased up to 40-folds as compared to controls (Pb only) depending on the type of chelator used. Shoot accumulations of Pb varied from 0.1 to 0.42% (dry weight) depending on the concentration of chelators used. - Sesbania drummondii tolerates and accumulates high concentrations of Pb

Standard practice for preparing sulfur prints for macrostructural evaluation

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This practice provides information required to prepare sulfur prints (also referred to as Baumann Prints) of most ferrous alloys to reveal the distribution of sulfide inclusions. 1.2 The sulfur print reveals the distribution of sulfides in steels with bulk sulfur contents between about 0.010 and 0.40 weight percent. 1.3 Certain steels contain complex sulfides that do not respond to the test solutions, for example, steels containing titanium sulfides or chromium sulfides. 1.4 The sulfur print test is a qualitative test. The density of the print image should not be used to assess the sulfur content of a steel. Under carefully controlled conditions, it is possible to compare print image intensities if the images are formed only by manganese sulfides. 1.5 The sulfur print image will reveal details of the solidification pattern or metal flow from hot or cold working on appropriately chosen and prepared test specimens. 1.6 This practice does not address acceptance criteria based on the use of the method. ...

Simultaneous removal of nitrogen oxides and sulfur oxides from combustion gases

Science.gov (United States)

Clay, David T.; Lynn, Scott

1976-10-19

A process for the simultaneous removal of sulfur oxides and nitrogen oxides from power plant stack gases comprising contacting the stack gases with a supported iron oxide catalyst/absorbent in the presence of sufficient reducing agent selected from the group consisting of carbon monoxide, hydrogen, and mixtures thereof, to provide a net reducing atmosphere in the SO.sub.x /NO.sub.x removal zone. The sulfur oxides are removed by absorption substantially as iron sulfide, and nitrogen oxides are removed by catalytic reduction to nitrogen and ammonia. The spent iron oxide catalyst/absorbent is regenerated by oxidation and is recycled to the contacting zone. Sulfur dioxide is also produced during regeneration and can be utilized in the production of sulfuric acid and/or sulfur.

Photocatalyzed removal of lead ion from lead-chelator solution

Energy Technology Data Exchange (ETDEWEB)

Cho, Young Hyun; Na, Jung Won; Sung, Ki Woung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-07-01

The present study was undertaken to examine the influence of such chelating agents on the ease and speed of photocatalyzed metal removal and deposition. With excess EDTA, the free EDTA competes with Pb for oxidation, and at a ten fold excess, no lead oxidation (hence removal) occurs. With insufficient EDTA, the corresponding initial concentration of Pb-EDTA is decreased; after its destruction, the remaining Pb{sup 2+} is removed more slowly, at rates found with lead nitrate solution. The net result is that the maximum rate of lead deposition occurs at the stoichiometric ratio of 1:1 EDTA : Pb{sup 2+}.

Sulfur metabolism in phototrophic sulfur bacteria

DEFF Research Database (Denmark)

Frigaard, Niels-Ulrik; Dahl, Christiane

2008-01-01

Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB......). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms...... in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative...

Effectiveness of chelation therapy with time after acute uranium intoxication

International Nuclear Information System (INIS)

Domingo, J.L.; Ortega, A.; Llobet, J.M.; Corbella, J.

1990-01-01

The effect of increasing the time interval between acute uranium exposure and chelation therapy was studied in male Swiss mice. Gallic acid, 4,5-dihydroxy-1,3- benzenedisulfonic acid (Tiron), diethylenetriaminepentaacetic acid (DTPA), and 5-aminosalicylic acid (5-AS) were administered ip at 0, 0.25, 1, 4, and 24 hr after sc injection of 10 mg/kg of uranyl acetate dihydrate. Chelating agents were given at doses equal to one-fourth of their respective LD50 values. Daily elimination of uranium into urine and feces was determined for 4 days after which time the mice were killed, and the concentration of uranium was measured in kidney, spleen, and bone. The excretion of uranium was especially rapid in the first 24 hr. Treatment with Tiron or gallic acid at 0, 0.25, or 1 hr after uranium exposure significantly increased the total excretion of the metal. In kidney and bone, only administration of Tiron at 0, 0.25, or 1 hr after uranium injection, or gallic acid at 1 hr after uranium exposure significantly reduced tissue uranium concentrations. Treatment at later times (4 to 24 hr) did not increase the total excretion of the metal and did not decrease the tissue uranium concentrations 4 days after uranyl acetate administration. The results show that the length of time before initiating chelation therapy for acute uranium intoxication greatly influences the effectiveness of this therapy

One-step chemical bath deposition and photocatalytic activity of Cu2O thin films with orientation and size controlled by a chelating agent

International Nuclear Information System (INIS)

Xu, HaiYan; Dong, JinKuang; Chen, Chen

2014-01-01

Nanocrystalline cuprous oxide (Cu 2 O) thin films were prepared via a one-step chemical bath deposition (CBD) method. The effects of a chelating agent on the orientation, morphology, crystallite size, and photocatalytic activity of the thin films were carefully examined using X-ray diffractometry, scanning electron microscopy, and UV–vis spectrophotometry. The results confirmed that the crystallite size as well as the orientation of the films was dependent on the volume of trisodium citrate (TSC), demonstrating that the band gap ranged from 2.71 eV to 2.49 eV. The morphology and number density of the thin films also depended on the volume of TSC. In addition, the obtained Cu 2 O thin films could degrade methyl orange (MO) efficiently in the presence of H 2 O 2 under visible-light irradiation, and the mechanism for the enhanced photocatalytic activity of the Cu 2 O thin films with the assistance of H 2 O 2 was also explored in detail. - Graphical abstract: Nano-structured Cu 2 O thin films have been prepared by a one-step chemical bath deposition method. The number density, crystallite size, surface morphology and orientation of these thin films could be tailored by chelating agent. The results confirmed that the crystallite size as well as the orientation of the thin films was dependent on the volume of TSC, showed that the band gap ranged from 2.71 eV to 2.49 eV. The formation mechanism of the Cu 2 O particles could be illuminated by an oriented attachment mode. In addition, the obtained Cu 2 O thin films degraded methyl orange efficiently in the presence of H 2 O 2 under the irradiation of visible light, and the mechanism for photocatalytic reaction was also discussed in detail. - Highlights: • Oriented Cu 2 O thin films were prepared by one-step chemical bath deposition. • Orientation and crystallite size were dependent on trisodium citrate volume. • The enhanced visible light degradation mechanism was systematically studied. • Oriented attachment

Iron-montmorillonite clays as active sorbents for the decontamination of hazardous chemical warfare agents.

Science.gov (United States)

Carniato, F; Bisio, C; Evangelisti, C; Psaro, R; Dal Santo, V; Costenaro, D; Marchese, L; Guidotti, M

2018-02-27

A class of heterogeneous catalysts based on commercial bentonite from natural origin, containing at least 80 wt% of montmorillonite clay, was designed to transform selectively and under mild conditions toxic organosulfur and organophosphorus chemical warfare agents into non-noxious products with a reduced impact on health and environment. The bentonite from the natural origin was modified by introducing iron species and acid sites in the interlayer space, aiming to obtain a sorbent with strong catalytic oxidising and hydrolytic properties. The catalytic performance of these materials was evaluated in the oxidative abatement of (2-chloroethyl)ethyl sulfide (CEES), a simulant of sulfur mustard, in the presence of aqueous hydrogen peroxide as an oxidant. A new decontamination formulation was, moreover, proposed and obtained by mixing sodium perborate, as a solid oxidant, to iron-bentonite catalysts. Solid-phase decontamination tests, performed on a cotton textile support contaminated with organosulfide and organophosphonate simulant agents revealed the good activity of the solid formulation, especially in the in situ detoxification of blistering agents. Tests carried out on the real blistering warfare agent, sulfur mustard (HD agent), showed that, thanks to the co-presence of the iron-based clay together with the solid oxidant component, a good decontamination of the test surface from the real warfare agent could be achieved (80% contaminant degradation, under ambient conditions, in 24 h).

Monitoring the progression of calcium and protein solubilisation as affected by calcium chelators during small-scale manufacture of casein-based food matrices.

Science.gov (United States)

McIntyre, Irene; O'Sullivan, Michael; O'Riordan, Dolores

2017-12-15

Calcium and protein solubilisation during small-scale manufacture of semi-solid casein-based food matrices was investigated and found to be very different in the presence or absence of calcium chelating salts. Calcium concentrations in the dispersed phase increased and calcium-ion activity (A Ca ++ ) decreased during manufacture of the matrices containing calcium chelating salts; with ∼23% of total calcium solubilised by the end of manufacture. In the absence of calcium chelating salts, these concentrations were significantly lower at equivalent processing times and remained unchanged as did A Ca ++ , throughout manufacture. The protein content of the dispersed phase was low (≤3% of total protein), but was significantly higher for matrices containing calcium chelating salts. This study elucidates the critical role of calcium chelating salts in modulating casein hydration and dispersion and gives an indication of the levels of soluble calcium and protein required to allow matrix formation during manufacture of casein-based food structures e.g. processed and analogue cheese. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation of novel polyamine-type chelating resin with hyperbranched structures and its adsorption performance

Science.gov (United States)

Zhao, Wei; Wang, Huan; Li, Yuhong; Li, Chenxi

2018-01-01

This paper explored the method of combining atom transfer radical polymerization (ATRP) technology and hyperbranched polymer principle to prepare the high capacity chelating resin. First, surface-initiated atom transfer radical polymerization (SI-ATRP) method was used to graft glycidyl methacrylate (GMA) on chloromethylated cross-linked styrene-divinylbenzene resin, and then the novel polyamine chelating resin with a kind of hyperbranched structure was prepared through the amination reaction between amino group of (2-aminoethyl) triamine and epoxy group in GMA. This resin had a selective effect on As(V) and Cr(VI) at a relatively low pH and can be used for the disposal of waste water containing As(V) and Cr(VI). It had a relatively strong adsorption effect on Cu(II), Pb(II), Cd(II) and Cr(III) and can be used for the disposal of heavy metal ion waste water. The finding was that, the adsorption capacity of resin on the studied heavy metal ions was higher than that of the chelating resin synthesized by traditional technology and also higher than that of the resin modified by ATRP technology and bifunctional chelator, indicating that the combination of ATRP and hyperbranched polymer concept is an effective method to prepare chelating resin with high capacity. PMID:29515875

Preparation of novel polyamine-type chelating resin with hyperbranched structures and its adsorption performance

Science.gov (United States)

Chen, Youning; Zhao, Wei; Wang, Huan; Li, Yuhong; Li, Chenxi

2018-02-01

This paper explored the method of combining atom transfer radical polymerization (ATRP) technology and hyperbranched polymer principle to prepare the high capacity chelating resin. First, surface-initiated atom transfer radical polymerization (SI-ATRP) method was used to graft glycidyl methacrylate (GMA) on chloromethylated cross-linked styrene-divinylbenzene resin, and then the novel polyamine chelating resin with a kind of hyperbranched structure was prepared through the amination reaction between amino group of (2-aminoethyl) triamine and epoxy group in GMA. This resin had a selective effect on As(V) and Cr(VI) at a relatively low pH and can be used for the disposal of waste water containing As(V) and Cr(VI). It had a relatively strong adsorption effect on Cu(II), Pb(II), Cd(II) and Cr(III) and can be used for the disposal of heavy metal ion waste water. The finding was that, the adsorption capacity of resin on the studied heavy metal ions was higher than that of the chelating resin synthesized by traditional technology and also higher than that of the resin modified by ATRP technology and bifunctional chelator, indicating that the combination of ATRP and hyperbranched polymer concept is an effective method to prepare chelating resin with high capacity.

Preparation and electrochemical performance of sulfur-alumina cathode material for lithium-sulfur batteries

Energy Technology Data Exchange (ETDEWEB)

Dong, Kang [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China); Wang, Shengping, E-mail: spwang@cug.edu.cn [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China); Zhang, Hanyu; Wu, Jinping [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China)

2013-06-01

Highlights: ► Micron-sized alumina was synthesized as adsorbent for lithium-sulfur batteries. ► Sulfur-alumina material was synthesized via crystallizing nucleation. ► The Al{sub 2}O{sub 3} can provide surface area for the deposition of Li{sub 2}S and Li{sub 2}S{sub 2}. ► The discharge capacity of the battery is improved during the first several cycles. - Abstract: Nano-sized sulfur particles exhibiting good adhesion with conducting acetylene black and alumina composite materials were synthesized by means of an evaporated solvent and a concentrated crystallization method for use as the cathodes of lithium-sulfur batteries. The composites were characterized and examined by X-ray diffraction, environmental scanning electron microscopy and electrochemical methods, such as cyclic voltammetry, electrical impedance spectroscopy and charge–discharge tests. Micron-sized flaky alumina was employed as an adsorbent for the cathode material. The initial discharge capacity of the cathode with the added alumina was 1171 mAh g{sup −1}, and the remaining capacity was 585 mAh g{sup −1} after 50 cycles at 0.25 mA cm{sup −2}. Compared with bare sulfur electrodes, the electrodes containing alumina showed an obviously superior cycle performance, confirming that alumina can contribute to reducing the dissolution of polysulfides into electrolytes during the sulfur charge–discharge process.

Overview of current chelation practices

Directory of Open Access Journals (Sweden)

Y. Aydinok

2011-12-01

Full Text Available Deferoxamine (DFO is reference standard therapy for transfusional iron overload since the 1980s. Although it is a highly effective iron chelator, the compliance problem to subcutaneous administration of DFO remains as the major problem. The oral chelator Deferiprone (DFP has no marketing licence in North America, however, it has been licensed in India since 1994 and the European Union (EU granted marketing approval for DFP in 1999, specifically for patients with thalassemia major when DFO is inadequate, intolerable or unacceptable. There are still limited data available on the use of DFP in children between 6 and 10 years of age, and no data on DFP use in children under 6 years of age. Subsequently the oral chelator Deferasirox (DFX was approved by FDA and EMA for the treatment of patients with transfusional iron overload -older than 2 years of age- as first line therapy, in 2005 and 2006 respectively. The primary objective of iron chelation is to maintain body iron at safe levels at all times but once iron is accumulated, the objective of iron chelation is to reduce tissue iron to safe levels which is a slow process. The chelation regimen, dose and frequency of administration, of the chelator(s are mainly determined based on body iron burden, presence of myocardial iron and the transfusional iron loading rate. A proper monitoring of chelation is of importance for measuring the response rate to a particular regimen and providing dose adjustments to enhance chelation efficacy and to avoid toxicity. Efficacy of a chelation regimen may exhibit individual variability resulting from factors such as absorbtion and metabolism of the chelator. Tolerability and compliance are also individual variables effecting the response to chelation. Understanding of advantages and limitations of chelators, accurately determining chelation needs of patients with iron overload and designing individualized chelation regimens with less toxicity but optimum efficacy

The future of airborne sulfur-containing particles in the absence of fossil fuel sulfur dioxide emissions.

Science.gov (United States)

Perraud, Véronique; Horne, Jeremy R; Martinez, Andrew S; Kalinowski, Jaroslaw; Meinardi, Simone; Dawson, Matthew L; Wingen, Lisa M; Dabdub, Donald; Blake, Donald R; Gerber, R Benny; Finlayson-Pitts, Barbara J

2015-11-03

Sulfuric acid (H2SO4), formed from oxidation of sulfur dioxide (SO2) emitted during fossil fuel combustion, is a major precursor of new airborne particles, which have well-documented detrimental effects on health, air quality, and climate. Another precursor is methanesulfonic acid (MSA), produced simultaneously with SO2 during the atmospheric oxidation of organosulfur compounds (OSCs), such as dimethyl sulfide. In the present work, a multidisciplinary approach is used to examine how contributions of H2SO4 and MSA to particle formation will change in a large coastal urban area as anthropogenic fossil fuel emissions of SO2 decline. The 3-dimensional University of California Irvine-California Institute of Technology airshed model is used to compare atmospheric concentrations of gas phase MSA, H2SO4, and SO2 under current emissions of fossil fuel-associated SO2 and a best-case futuristic scenario with zero fossil fuel sulfur emissions. Model additions include results from (i) quantum chemical calculations that clarify the previously uncertain gas phase mechanism of formation of MSA and (ii) a combination of published and experimental estimates of OSC emissions, such as those from marine, agricultural, and urban processes, which include pet waste and human breath. Results show that in the zero anthropogenic SO2 emissions case, particle formation potential from H2SO4 will drop by about two orders of magnitude compared with the current situation. However, particles will continue to be generated from the oxidation of natural and anthropogenic sources of OSCs, with contributions from MSA and H2SO4 of a similar order of magnitude. This could be particularly important in agricultural areas where there are significant sources of OSCs.

Comparison of the redox chemistry of sulfur- and selenium-containing analogs of uracil✰

Science.gov (United States)

Payne, N. Connor; Geissler, Andrew; Button, Aileen; Sasuclark, Alexandru R.; Schroll, Alayne L.; Ruggles, Erik L.; Gladyshev, Vadim N.; Hondal, Robert J.

2017-01-01

Selenium is present in proteins in the form of selenocysteine, where this amino acid serves catalytic oxidoreductase functions. The use of selenocysteine in nature is strongly associated with redox catalysis. However, selenium is also found in a 2-selenouridine moiety at the wobble position of tRNAGlu, tRNAGln and tRNALys. It is thought that the modifications of the wobble position of the tRNA improves the selectivity of the codon-anticodon pair as a result of the physico-chemical changes that result from substitution of sulfur and selenium for oxygen. Both selenocysteine and 2-selenouridine have widespread analogs, cysteine and thiouridine, where sulfur is used instead. To examine the role of selenium in 2-selenouridine, we comparatively analyzed the oxidation reactions of sulfur-containing 2-thiouracil-5-carboxylic acid (s2c5Ura) and its selenium analog 2-selenouracil-5-carboxylic acid (se2c5Ura) using 1H-NMR spectroscopy, 77Se-NMR spectroscopy, and liquid chromatography-mass spectrometry. Treatment of s2c5Ura with hydrogen peroxide led to oxidized intermediates, followed by irreversible desulfurization to form uracil-5-carboxylic acid (c5Ura). In contrast, se2c5Ura oxidation resulted in a diselenide intermediate, followed by conversion to the seleninic acid, both of which could be readily reduced by ascorbate and glutathione. Glutathione and ascorbate only minimally prevented desulfurization of s2c5Ura, whereas very little deselenization of se2c5Ura occurred in the presence of the same antioxidants. In addition, se2c5Ura but not s2c5Ura showed glutathione peroxidase activity, further suggesting that oxidation of se2c5Ura is readily reversible, while oxidation of s2c5Ura is not. The results of the study of these model nucleobases suggest that the use of 2-selenouridine is related to resistance to oxidative inactivation that otherwise characterizes 2-thiouridine. As the use of selenocysteine in proteins also confers resistance to oxidation, our findings suggest a

Comparison of the redox chemistry of sulfur- and selenium-containing analogs of uracil.

Science.gov (United States)

Payne, N Connor; Geissler, Andrew; Button, Aileen; Sasuclark, Alexandru R; Schroll, Alayne L; Ruggles, Erik L; Gladyshev, Vadim N; Hondal, Robert J

2017-03-01

Selenium is present in proteins in the form of selenocysteine, where this amino acid serves catalytic oxidoreductase functions. The use of selenocysteine in nature is strongly associated with redox catalysis. However, selenium is also found in a 2-selenouridine moiety at the wobble position of tRNA Glu , tRNA Gln and tRNA Lys . It is thought that the modifications of the wobble position of the tRNA improves the selectivity of the codon-anticodon pair as a result of the physico-chemical changes that result from substitution of sulfur and selenium for oxygen. Both selenocysteine and 2-selenouridine have widespread analogs, cysteine and thiouridine, where sulfur is used instead. To examine the role of selenium in 2-selenouridine, we comparatively analyzed the oxidation reactions of sulfur-containing 2-thiouracil-5-carboxylic acid (s 2 c 5 Ura) and its selenium analog 2-selenouracil-5-carboxylic acid (se 2 c 5 Ura) using 1 H-NMR spectroscopy, 77 Se-NMR spectroscopy, and liquid chromatography-mass spectrometry. Treatment of s 2 c 5 Ura with hydrogen peroxide led to oxidized intermediates, followed by irreversible desulfurization to form uracil-5-carboxylic acid (c 5 Ura). In contrast, se 2 c 5 Ura oxidation resulted in a diselenide intermediate, followed by conversion to the seleninic acid, both of which could be readily reduced by ascorbate and glutathione. Glutathione and ascorbate only minimally prevented desulfurization of s 2 c 5 Ura, whereas very little deselenization of se 2 c 5 Ura occurred in the presence of the same antioxidants. In addition, se 2 c 5 Ura but not s 2 c 5 Ura showed glutathione peroxidase activity, further suggesting that oxidation of se 2 c 5 Ura is readily reversible, while oxidation of s 2 c 5 Ura is not. The results of the study of these model nucleobases suggest that the use of 2-selenouridine is related to resistance to oxidative inactivation that otherwise characterizes 2-thiouridine. As the use of selenocysteine in proteins also confers

Effect of different chelated zinc sources on the growth and yield of maize (Zea mays L.

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M. Tahir

2009-05-01

Full Text Available A field study was conducted at Agronomic Research Area, University of Agriculture, Faisalabad during spring, 2007 to evaluate the effect of different chelated zinc sources on growth and yield of maize (Zea mays L.. Crop was sown on well prepared soil in 1st week of March, 2007. The experiment was laid out according to randomized complete block design. The treatments comprised of different chelated zinc sources: ZnSO4-DTPA, ZnSO4-Fulvate, ZnSO4-Lignosulphonate, ZnSO4-EDTA and ZnSO4-H2O along with control (no zinc, repeated three times. Results showed that number of cobs plant-1, grain rows cob-1 and oil contents did not differ significantly. However, differences among treatments for plant height at harvest (cm, leaf area plant-1 (cm2, stem diameter (cm, cob length (cm, cob diameter (cm, 100-grains weight (g, number of grains cob-1, grains weight cob-1(g, biological yield (tons ha-1, grain yield (tons ha-1 and protein contents (% were significantly higher. Moreover, results also revealed that ZnSO4-DPTA was found the most effective Zn chelated source among all the treatments. Rest of the chelating agents were not too impressive as they showed varied response for different variables. The result of this experiment suggest further experimentation to explore behaviour of Zn-DTPA with other macro and micro nutrients and to calculate cost benefit ratio for use ofZn chelated compounds.

Identification of novel sulphur-containing steroids in sediments and petroleum; Probable incorporation of sulfur into Delta(5,7)-sterols during early diagenesis

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Schouten, S.; Leeuw, J.W. de; Duin, A.C.T. van; Geenevasen, J.A.J.

1999-01-01

A novel sulfur-containing sterane, 4,7-epithio-5-cholestane, has been identified in a sediment extract from the Miocene Northern Apennines marl (Italy) after its isolation by column chromatography and high pressure liquid chromatography. The compound has been characterised by GC-MS and mild Nickel

Effect of Ionic and Chelate Assisted Hexavalent Chromium on Mung Bean Seedlings (Vigna radiata L. wilczek. var k-851 During Seedling Growth

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Mohanty, Monalisa

2013-04-01

Full Text Available The effect of Cr+6 with and without chelating agents were assessed in mung bean seedlings grown hydroponically. It was noted that the growth parameters showed a declining trend with increasing Cr+6 concentrations without chelate application. Among the seedlings grown with chelated chromium complexes, Cr+6–DTPA (10µM showed highest growth rate of roots as well as shoots. At higher concentration of Chromium i.e. Cr+6 (100µM, there exhibited high chlorophyll content in mung bean leaves where the seedlings showed stunted growth. The seedlings treated without and with chelated chromium complexes showed increased proline content as compared to control. The enzymatic study showed that, the catalase activity was maximum in shoots as compared to roots and the reverse is true in the case of peroxidase activity i.e. the roots showed higher value than that of the shoots.

Development of Iron-Chelating Poly(ethylene terephthalate) Packaging for Inhibiting Lipid Oxidation in Oil-in-Water Emulsions.

Science.gov (United States)

Johnson, David R; Tian, Fang; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

2015-05-27

Foods such as bulk oils, salad dressings, and nutritionally fortified beverages that are susceptible to oxidative degradation are often packaged in poly(ethylene terephthalate) (PET) bottles with metal chelators added to the food to maintain product quality. In the present work, a metal-chelating active packaging material is designed and characterized, in which poly(hydroxamic acid) (PHA) metal-chelating moieties were grafted from the surface of PET. Biomimetic PHA groups were grafted in a two-step UV-initiated process without the use of a photoinitiator. Surface characterization of the films by attenuated total reflective Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM) suggested successful grafting and conversion of poly(hydroxyethyl acrylate) (PHEA) to PHA chelating moieties from the surface of PET. Colorimetric (ferrozine) and inductively coupled plasma mass spectroscopy (ICP-MS) assays demonstrated the ability of PET-g-PHA to chelate iron in a low-pH (3.0) environment containing a competitive metal chelator (citric acid). Lipid oxidation studies demonstrated the antioxidant activity of PET-g-PHA films in inhibiting iron-promoted oxidation in an acidified oil-in-water (O/W) emulsion model system (pH 3.0). Particle size and ζ-potential analysis indicated that the addition of PET-g-PHA films did not affect the physical stability of the emulsion system. This work suggests that biomimetic chelating moieties can be grafted from PET and effectively inhibit iron-promoted degradation reactions, enabling removal of metal-chelating additives from product formulations.

Wax solidification of drying agents containing tritiated water

International Nuclear Information System (INIS)

Mishikawa, M.; Kido, H.

1984-01-01

It is necessary to immobilize the tritium not to give any impact on the environmental biosphere because tritium may give profound effects in the metabolic pathway. One of the most probable methods of immobilizing tritium would be incorporation of tritiated water in solid forms. Any drying or dehydration technique would be effective in a tritium cleanup system for off-gas streams containing tritium or tritiated water. Commonly used drying agents such as activated alumina, silica gel, molecular sieves and calcium sulfate are of value for removal of water vapour from air or other gases. For long term tritium storage, however, these adsorptive materials should be enveloped to prevent contact with water or water vapour because the rate of leaching, evaporation or diffusion of tritium from these porous materials is so large. The beeswax solidification method of the packed bed of drying agents adsorbing tritiated water is developed in this study, where the wax solidification procedure is performed by pouring the melt of wax into the void space of the packed bed of the drying agents and successive gradual cooling. The observed values of diffusivity or permeability of tritium in the wax solidified materials are about one-thousandth of those obtained for the cement block. Effect of coating on the rate of leaching is also discussed

Biological behaviour of some 67Ga and 64Cu chelates

International Nuclear Information System (INIS)

Leonovicova, T.; Angelis, B.; Cifka, J.; Cifkova, I.

1984-01-01

Chelates of 67 Ga and 64 Cu with iminodiacetic acid (IDA) and its two phenyl derivatives as well as with nitrilotriacetic acid (NTA) and benzylnitrilotriacetic acid (BNTA) were prepared. All the chelates were found to be negatively charged. A study of the biological distribution of these chelates in rats during time intervals of 3 to 180 min showed that the chelate of 67 Ga with IDA substituted at a phenyl by a hydrophobic substituent is excreted by the kidneys into the urine at a much higher rate than the IDA chelate of 67 Ga. The excretion of NTA and BNTA chelates of 67 Ga is the opposite. Blood clearance of 64 Cu chelates is more rapid than that of 67 Ga chelates. Chelates of 64 Cu accumulate in the liver and with the bile are slowly excreted into the intestines, urinary excretion is negligible. (author)

Schiff bases derived from L-Tyrosine L-Tryptophan and their Cu(II) chelates as effective means for preventive-treatment of radiation injuries

International Nuclear Information System (INIS)

Malakyan, M.H.; Bajinyan, S.A.; Matosyan, V.H.; Tonoyan, V.J.; Babayan, K.N.; Boyajyan, A.S.; Yeghiazaryan, D.E.; Vardevanyan, L.A.; Sorenson, J.R.J.

2008-01-01

Full text: Study on essential metallo element chelates as radioprotectors presents a promising direction in a search for and development of novel anti-radiation agents and offers a new approach to overcome the pathological effects of ionizing radiation. The key idea elucidating the radioprotective effects of metallo element-containing chelates of amino acid derivatives is their role in stimulation of de novo synthesis of metallo element-dependent enzymes required for recovery of hemopoietic activity and immuno competency lost as a consequence of radiation damage. Aimed to develop novel anti-radiation remedies of less toxicity and high efficacy, Schiff bases derived from L-Tyrosine and L-Tryptophan and their Cu(II) chelates were synthesized. In experiments in vitro and in vivo biological and pharmacological properties of the mentioned Schiff Bases and their copper complexes are under study. According to the results obtained, L-Tyrosinate and L-Tryptophanate Schiff bases are low toxic compounds with a weak antioxidant activity and exert radioprotective effects in case of animal X-ray irradiation at a dose level equal or less than LD 50/30 . Unlike Schiff Bases, their appropriate Cu(II) chelates possess high anti radical/antioxidant activity and manifest expressed radio-protective action at LD 100/30 dose of ionizing radiation. Anti-radiation effects of amino acid Schiff bases and their metallo chelates are manifested in case of both subcutaneous and oral single administration to the animal organism at 10, 20, or 40 mg/kg 1, 3, 6, or 24 hours prior to radiation exposure. Conclusions are drawn basing on determinations of survival and average life-span indices of irradiated animals, as well as on studies for their hematological, biochemical, immunological, biophysical indices. It is revealed that on the background of preliminary administration of the compounds studied to the animal organism the characteristics of DNA are significantly improved, the immune status

Studies on derivatives of bat chelates labelled with 67Ca, 113mIn and 201Tl: Pt. 1

International Nuclear Information System (INIS)

Meng Min; Jin Yutai; Liu Boli; Zhu Lin

1989-01-01

The use of 3, 3, 10, 10-tetraethy 1-1, 2-dithio-5, 8-diazacyclodecane (BAT-TE) and 3, 3, 6, 6, 10, 10-hexamethyl-1, 2-dithio-5, 8-diazacy-clodecane (BAT-HM) as new ligands for the preparation of M-BAT-TE (M = Ca 3+ , In 3+ ) and M-BAT-HM (M = Ca 3+ , In 3+ , Tl 3+ ) were investigated. The chelating reactions with high labelling yield are fairly simple and rapid. The biodistribution of BAT derivative chelates in mice exhibited considerable myocardial uptake and good selectivity. Slow washout in heart and high heart-to-blood ratios were observed during the period from 2 min to 30 min after intravenous injection. Based on these experimental results, M-BAT-TE (M = Ca 3+ , In 3+ ) and M-BAT-HM (M = Ca 3+ , IN 3+ , Tl 3+ ) are considered as potential myocardial imaging agents, and particularly Tl-BAT-HM is likely a promising imaging agent

Preparative separation of sulfur-containing diketopiperazines from marine fungus Cladosporium sp. using high-speed counter-current chromatography in stepwise elution mode.

Science.gov (United States)

Gu, Binbin; Zhang, Yanying; Ding, Lijian; He, Shan; Wu, Bin; Dong, Junde; Zhu, Peng; Chen, Juanjuan; Zhang, Jinrong; Yan, Xiaojun

2015-01-09

High-speed counter-current chromatography (HSCCC) was successively applied to the separation of three sulfur-containing diketopiperazines (DKPs) (including two new compounds cladosporin A (1) and cladosporin B (3), and a known compound haematocin (2)) from a marine fungus Cladosporium sp. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at (1:1:1:1, v/v) and (2:1:2:1, v/v), in stepwise elution mode, was used for HSCCC. The preparative HSCCC separation was performed on 300 mg of crude sample yielding 26.7 mg of compound 3 at a purity of over 95%, 53.6 mg of a mixture of compounds 1 and 2, which was further separated by preparative-HPLC yielding 14.3 mg of compound 1 and 25.4 mg of compound 2 each at a purity of over 95%. Their structures were established by spectroscopic methods. The sulfur-containing DKPs suppressed the proliferation of hepatocellular carcinoma cell line HepG2. The present work represents the first application of HSCCC in the efficient preparation of marine fungal natural products.

Preparative Separation of Sulfur-Containing Diketopiperazines from Marine Fungus Cladosporium sp. Using High-Speed Counter-Current Chromatography in Stepwise Elution Mode

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Binbin Gu

2015-01-01

Full Text Available High-speed counter-current chromatography (HSCCC was successively applied to the separation of three sulfur-containing diketopiperazines (DKPs (including two new compounds cladosporin A (1 and cladosporin B (3, and a known compound haematocin (2 from a marine fungus Cladosporium sp. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at (1:1:1:1, v/v and (2:1:2:1, v/v, in stepwise elution mode, was used for HSCCC. The preparative HSCCC separation was performed on 300 mg of crude sample yielding 26.7 mg of compound 3 at a purity of over 95%, 53.6 mg of a mixture of compounds 1 and 2, which was further separated by preparative-HPLC yielding 14.3 mg of compound 1 and 25.4 mg of compound 2 each at a purity of over 95%. Their structures were established by spectroscopic methods. The sulfur-containing DKPs suppressed the proliferation of hepatocellular carcinoma cell line HepG2. The present work represents the first application of HSCCC in the efficient preparation of marine fungal natural products.

Sulfur in human nutrition - effects beyond protein synthesis

NARCIS (Netherlands)

Gertjan Schaafsma

2008-01-01

That sulfur is essential to humans is based on the requirement of S-animo acids for normal growth and maintenance of nitrogen balance and not on the optimization of metabolic proccesses involving the synthesis of non-protein sulphur containing compounds. This paper reviews the significance of sulfur

Chelated Nitrogen-Sulphur-Codoped TiO2: Synthesis, Characterization, Mechanistic, and UV/Visible Photocatalytic Studies

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Hayat Khan

2017-01-01

Full Text Available This study presents in detail the physicochemical, photoluminescent, and photocatalytic properties of carboxylic acid chelated nitrogen-sulphur-codoped TiO2. From the Fourier transform infrared spectroscopic study, it was revealed that the formate group formed bidentate bridging linkage while the acetate group coordinated in a bidentate chelating mode with a titanium precursor. In compliance with X-ray diffraction data, the anatase to rutile transformation temperature was extended due to carboxylic acid chelation and NS codoping. Raman analysis indicated four Raman peaks at 146, 392, 512, and 632 cm−1 for the precalcined chelated TiO2; on incorporation with NS dopants, an increase in Raman intensity for these peaks was recorded, indicating the structure stability of the anatase phase. Furthermore, X-ray photoelectron spectroscopic study revealed the presence of anionic doping of nitrogen and cationic doping of sulphur in the lattice of TiO2. When evaluating the UV-visible photodegradation rate of 4-chlorophenol, the modified TiO2 (NS0.06-TFA showed the highest photocatalytic activity. In connection with the activity tests, several scavenger agents were employed to elucidate the significance of the different reactive oxidizing species during the photocatalytic process. Moreover, the transfer pathways of photogenerated carriers and the photocatalytic reaction mechanism of modified TiO2 were also explained in detail.

Determination of cadmium in seawater by chelate vapor generation atomic fluorescence spectrometry

Science.gov (United States)

Sun, Rui; Ma, Guopeng; Duan, Xuchuan; Sun, Jinsheng

2018-03-01

A method for the determination of cadmium in seawater by chelate vapor generation (Che-VG) atomic fluorescence spectrometry is described. Several commercially available chelating agents, including ammonium pyrrolidine dithiocarbamate (APDC), sodium dimethyl dithiocarbamate (DMDTC), ammonium dibutyl dithiophosphate (DBDTP) and sodium O,O-diethyl dithiophosphate (DEDTP), are compared with sodium diethyldithiocarbamate (DDTC) for the Che-VG of cadmium, and results showed that DDTC and DEDTP had very good cadmium signal intensity. The effect of the conditions of Che-VG with DDTC on the intensity of cadmium signal was investigated. Under the optimal conditions, 85 ± 3% Che-VG efficiency is obtained for cadmium. The detection limit (3σ) obtained in the optimal conditions was 0.19 ng ml- 1. The relative standard deviation (RSD, %) for ten replicate determinations at 2 ng ml- 1 Cd was 3.42%. The proposed method was successfully applied to the ultratrace determination of cadmium in seawater samples by the standard addition method.

f-Element Ion Chelation in Highly Basic Media

International Nuclear Information System (INIS)

Paine, Robert T.

1999-01-01

High-level radioactive waste (HLW) generated in the DOE complex is stored in tanks at several sites, but predominantly it is found at the Hanford reservation. Much of the material has been exposed to high pHs, consequently the waste exists in a complex, poorly understood mixture of solids, gels and solutions. The final waste remediation plan may involve chemical separation of fractions and a suitable, well developed molecular chemistry basis for performing these separations is not available. Indeed, the fundamental chemical behavior of most radioactive nuclides in basic media is not known. The goal of this project is to undertake fundamental studies of the coordination chemistry of f-element species in basic aqueous solutions containing common waste treatment ions (e.g., NO3 -, CO3 2-, organic carboxylates, and EDTA), as well as new waste scrubbing chelators produced in this study. The experimental agenda includes: 1. Studies of the speciation of Sr and Ln ions in basic solutions wit h and without common counterions; 2. Preparations of new multifunctional ligands that may act as strong, ion-specific chelators for Sr and/or Ln ions in basic media; and 3. Studies of the coordination and dissolution behavior of oxide-hydroxide species, as well as in insoluble sols, gels, and precipitates in combination with new chelating ligands. It is anticipated that this coordination chemistry will facilitate the design of advanced separation schemes required for handling the complex waste matrices found at the Hanford HLW facility

Behaviour of organic sulfur compounds in HPLC

International Nuclear Information System (INIS)

Freyholdt, T.

1982-01-01

The retention behaviour of organic sulfur compounds in the reverse-bonded-phase chromatography is characterized by determining the retention indices according to Kovats. The results of these studies show that the solubility of organic compounds in the eluting agent and the molar sorption surfaces of the solutes are the main factors determining the retention behaviour. Knowledge of the retention indices of above-mentioned compounds allows a quick interpretation of chromatograms obtained through a product analysis of γ-irradiated aqueous solutions of organic sulfur compounds. Dithia compounds of the type CH 3 -S-(CH 2 )sub(n)-S-Ch 3 (1 1. 2,4-Dithiapentane (n = 1) however will yield primarily monothio-S-methyl formate as a stable end product. The formation of oxygenic reaction products proceeds via sulfur-centred radical kations. Spin trapping experiments with nitroxyl radicals show that it is possible to trap radiation-chemically produced radicals of sulfurous substrates, but the thus obtained adducts with half-life periods of 4-5 min. cannot be identified by means of NMR, IR or mass spectroscopy. (orig.) [de

The use of auxiliary devices during irrigation to increase the cleaning ability of a chelating agent

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Marina Carvalho Prado

2017-05-01

Full Text Available Objectives This study investigated the cleaning ability of ultrasonically activated irrigation (UAI and a novel activation system with reciprocating motion (EC, EasyClean, Easy Equipamentos Odontológicos when used with a relatively new chelating agent (QMix, Dentsply. In addition, the effect of QMix solution when used for a shorter (1 minute and a longer application time (3 minutes was investigated. Materials and Methods Fifty permanent human teeth were prepared with K3 rotary system and 6% sodium hypochlorite. Samples were randomly assigned to five groups (n = 10 according to the final irrigation protocol: G1, negative control (distilled water; G2, positive control (QMix 1 minute; G3, QMix 1 minute/UAI; G4, QMix 1 minute/EC; G5, QMix 3 minutes. Subsequently the teeth were prepared and three photomicrographs were obtained in each root third of root walls, by scanning electron microscopy. Two blinded and pre-calibrated examiners evaluated the images using a four-category scoring system. Data were statistically analyzed using Kruskal-Wallis and Dunn tests (p < 0.05. Results There were differences among groups (p < 0.05. UAI showed better cleaning ability than EC (p < 0.05. There were improvements when QMix was used with auxiliary devices in comparison with conventional irrigation (p < 0.05. Conventional irrigation for 3 minutes presented significantly better results than its use for 1 minute (p < 0.05. Conclusions QMix should be used for 1 minute when it is used with UAI, since this final irrigation protocol showed the best performance and also allowed clinical optimization of this procedure.

Chelate-assisted phytoextraction of lead from contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Cooper, E.M.; Sims, J.T.; Cunningham, S.D.; Huang, J.W.; Berti, W.R.

1999-12-01

Phytoextraction, a remediation strategy for lead (Pb)-contaminated soils that removes soil Pb through plant uptake and harvest, may be enhanced by use of synthetic chelates. The authors evaluated Pb desorption from four contaminated soils by seven chelates (CDTA, DTPA, EDDHA, EFTA, HEDTA, HEIDA, and NTA) at three rates. The three most effective chelates (CDTA, DTPA, and HEDTA) were used in greenhouse studies with an uncontaminated soil and a Pb-contaminated soil to determine the effect of chelate type and rate on growth, Pb uptake, and plant elemental composition. Lead desorption varied with chelate and soil and increased with chelate rate, averaging 948 mg Pb kg{sup {minus}1} at the 20 mmol kg{sup {minus}1} rate vs. 28 mg Pb kg{sup {minus}1} by the control. The general ranking of chelate effectiveness, based on total Pb desorbed, was HEDTA > CDTA > DTPA > EGTA > HEIDA > EDDHA {approximately} NTA. Plant uptake of Pb from the contaminated soil was enhanced by CDTA, DTPA, and HEDTA, but with even the most effective treatment (corn, high CDTA rate), the amount of Pb extracted by plants was rather low. Lead extractable by the Toxicity Characteristic Leaching Procedure (TCLP) was increased from 9 mg L{sup {minus}1} in the control to from 47 to 174 mg L{sup {minus}1} in soils treated with 20 mmol kg{sup {minus}1} CDTA or DTPA and chelates generally caused a shift in Pb from resistant to more soluble chemical fractions.

Repurposing of Copper(II)-chelating Drugs for the Treatment of Neurodegenerative Diseases.

Science.gov (United States)

Lanza, Valeria; Milardi, Danilo; Di Natale, Giuseppe; Pappalardo, Giuseppe

2018-02-12

There is mounting urgency to find new drugs for the treatment of neurodegenerative disorders. A large number of reviews have exhaustively described either the molecular or clinical aspects of neurodegenerative diseases such as Alzheimer's (AD) and Parkinson's (PD). Conversely, reports outlining how known drugs in use for other diseases can also be effective as therapeutic agents in neurodegenerative diseases are less reported. This review focuses on the current uses of some copper(II) chelating molecules as potential drug candidates in neurodegeneration. Starting from the well-known harmful relationships existing between the dyshomeostasis and mis-management of metals and AD onset, we surveyed the experimental work reported in the literature, which deals with the repositioning of metal-chelating drugs in the field of neurodegenerative diseases. The reviewed papers were retrieved from common literature and their selection was limited to those describing the biomolecular aspects associated with neuroprotection. In particular, we emphasized the copper(II) coordination abilities of the selected drugs. Copper, together with zinc and iron, are known to play a key role in regulating neuronal functions. Changes in copper homeostasis are crucial for several neurodegenerative disorders. The studies included in this review may provide an overview on the current strategies aimed at repurposing copper (II) chelating drugs for the treatment of neurodegenerative disorders. Starting from the exemplary case of clioquinol repurposing, we discuss the challenge and the opportunities that repurposing of other metal-chelating drugs may provide (e.g. PBT-2, metformin and cyclodipeptides) in the treatment of neurodegenerative disease. In order to improve the success rate of drug repositioning, comprehensive studies on the molecular mechanism and therapeutic efficacy are still required. The present review upholds that drug repurposing makes significant advantages over drug discovery since

Screening of chelating ligands to enhance mercury accumulation from historically mercury-contaminated soils for phytoextraction.

Science.gov (United States)

Wang, Jianxu; Xia, Jicheng; Feng, Xinbin

2017-01-15

Screening of optimal chelating ligands which not only have high capacities to enhance plant uptake of mercury (Hg) from soil but also can decrease bioavailable Hg concentration in soil is necessary to establish a viable chemically-assisted phytoextraction. Therefore, Brassica juncea was exposed to historically Hg-contaminated soil (total Hg, 90 mg kg -1 ) to investigate the efficiency of seven chelating agents [ammonium thiosulphate, sodium thiosulphate, ammonium sulfate, ammonium chloride, sodium nitrate, ethylenediaminetetraacetic acid (EDTA), and sodium sulfite] at enhancing Hg phytoextraction; the leaching of bioavailable Hg caused by these chelating agents was also investigated. The Hg concentration in control (treated with double-distilled water) plant tissues was below 1 mg kg -1 . The remarkably higher Hg concentration was found in plants receiving ammonium thiosulphate and sodium sulfite treatments. The bioaccumulation factors and translocation factors of ammonium thiosulphate and sodium sulfite treatments were significantly higher than those of the other treatments. The more efficient uptake of Hg by plants upon treatment with ammonium thiosulphate and sodium sulfite compared to the other treatments might be explained by the formation of special Hg-thiosulphate complexes that could be preferentially taken up by the roots and transported in plant tissues. The application of sulfite significantly increased bioavailable Hg concentration in soil compared with that in initial soil and control soil, whereas ammonium thiosulphate significantly decreased bioavailable Hg concentration. The apparent decrease of bioavailable Hg in ammonium thiosulphate-treated soil compared with that in sodium sulfite-treated soil might be attributable to the unstable Hg-thiosulphate complexes formed between thiosulphate and Hg; they could react to produce less bioavailable Hg in the soil. The results of this study indicate that ammonium thiosulphate may be an optimal chelating

Partial oxidation of jet fuels over Rh/Al_2O_3. Design and reaction kinetics of sulfur-containing surrogates

International Nuclear Information System (INIS)

Baer, Julian Nicolaas

2016-01-01

The conversion of logistic fuels via catalytic partial oxidation (CPOX) on Rh/Al_2O_3 at short contact times is an efficient method for generating hydrogen-rich synthesis gas. Depending on the inlet conditions, fuel, and catalyst, high syngas yields, low by-product formation, and rates of high fuel conversion can be achieved. CPOX is relevant for mobile hydrogen generation, e.g., on board of airplanes in order to increase the fuel efficiency via fuel cell-based auxiliary power units. Jet fuels contain hundreds of different hydrocarbons and a significant amount of sulfur. The hydrocarbon composition and sulfur content of a jet fuel vary depending on distributor, origin, and refinement of the crude oil. Little is known about the influence of the various compounds on the synthesis-gas yield and the impact of sulfur on the product yield. In this work, the influence of three main chemical compounds of a jet fuel (aromatics, alkanes, and sulfur compounds) on syngas selectivity, the catalyst deactivation process, and reaction sequence is unraveled. As representative components of alkanes and aromatics, n-dodecane and 1,2,4-trimethylbenzene were chosen for ex-situ and in-situ investigations on the CPOX over Rh/Al_2O_3, respectively. Additionally, for a fixed paraffin-to-aromatics ratio, benzothiophene or dibenzothiophene were added as a sulfur component in three different concentrations. The knowledge gained about the catalytic partial oxidation of jet fuels and their surrogates is used to identify requirements for jet fuels in mobile applications based on CPOX and to optimize the overall system efficiency. The results show an influence of the surrogate composition on syngas selectivity. The tendency for syngas formation increases with higher paraffin contents. A growing tendency for by-product formation can be observed with increasing aromatics contents in the fuel. The impact of sulfur on the reaction system shows an immediate change in the product distribution. An

One-step chemical bath deposition and photocatalytic activity of Cu{sub 2}O thin films with orientation and size controlled by a chelating agent

Energy Technology Data Exchange (ETDEWEB)

Xu, HaiYan, E-mail: xuhaiyan@ahjzu.edu.cn; Dong, JinKuang, E-mail: dongjinkuang1988@126.com; Chen, Chen, E-mail: 13865901653@139.com

2014-01-15

Nanocrystalline cuprous oxide (Cu{sub 2}O) thin films were prepared via a one-step chemical bath deposition (CBD) method. The effects of a chelating agent on the orientation, morphology, crystallite size, and photocatalytic activity of the thin films were carefully examined using X-ray diffractometry, scanning electron microscopy, and UV–vis spectrophotometry. The results confirmed that the crystallite size as well as the orientation of the films was dependent on the volume of trisodium citrate (TSC), demonstrating that the band gap ranged from 2.71 eV to 2.49 eV. The morphology and number density of the thin films also depended on the volume of TSC. In addition, the obtained Cu{sub 2}O thin films could degrade methyl orange (MO) efficiently in the presence of H{sub 2}O{sub 2} under visible-light irradiation, and the mechanism for the enhanced photocatalytic activity of the Cu{sub 2}O thin films with the assistance of H{sub 2}O{sub 2} was also explored in detail. - Graphical abstract: Nano-structured Cu{sub 2}O thin films have been prepared by a one-step chemical bath deposition method. The number density, crystallite size, surface morphology and orientation of these thin films could be tailored by chelating agent. The results confirmed that the crystallite size as well as the orientation of the thin films was dependent on the volume of TSC, showed that the band gap ranged from 2.71 eV to 2.49 eV. The formation mechanism of the Cu{sub 2}O particles could be illuminated by an oriented attachment mode. In addition, the obtained Cu{sub 2}O thin films degraded methyl orange efficiently in the presence of H{sub 2}O{sub 2} under the irradiation of visible light, and the mechanism for photocatalytic reaction was also discussed in detail. - Highlights: • Oriented Cu{sub 2}O thin films were prepared by one-step chemical bath deposition. • Orientation and crystallite size were dependent on trisodium citrate volume. • The enhanced visible light degradation mechanism

Pengaruh sulfur terhadap sifat fisika campuran pale crepe dan SBR untuk karet tahan panas

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Arum Yuniari

2013-12-01

Full Text Available Sulfur plays an important role in the rubber vulcanization process especially in the formation of crosslinks. Heat resistant rubber made from mixing pale crepe and SBR requires the right amount of sulfur as crosslinking agent. The purpose of the study was to determine the effect of the addition of sulfur on the changes in physical properties before and after aging. Heat resistant rubber was made with variation of pale crepe/SBR: 80/20; 70/30; 60/40; 50/50 phr and sulfur variation of 1; 1.5 phr. The results showed that sulfur was influential in the crosslinks formation. The addition of 1 phr sulfur gave higher physical properties of the vulcanized with 1.5 phr sulfur. The changes of physical properties after aging process of the vulcanized with sulfur 1 phr was lower than the vulcanized with sulfur 1.5 phr. Vulcanized pale crepe/SBR (70/30 with 1 phr sulfur could be applied as heat-resistant rubber products.

[Susceptibility of enterococci to natural and synthetic iron chelators].

Science.gov (United States)

Lisiecki, Paweł; Mikucki, Jerzy

2002-01-01

A total of 79 strains of enterococci belonging to 10 species were tested for susceptibility to natural and synthetic iron chelators. All strains produced siderophores. These enterococci were susceptible to three synthetic iron chelators only: 8-hydroxyquinoline, disodium versenate (EDTA) and o-phenanthroline. They were resistant to all other synthetic chelators: ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA), nitrilotriacetate, 2,2'-bipiridyl, salicylic acid, 8-hydroxy-5-sulphonic acid and to all natural chelators: ovotransferrine, human apotransferrine, horse apoferritine, desferrioxamine B, ferrichrome and rhodotorulic acid. The relations between susceptibility/resistance, iron assimilation and structure and stability constants of iron chelators were discussed.

Mixed ligand chelates of rare earths in aqueous solution

International Nuclear Information System (INIS)

Lakhani, S.U.; Thakur, G.S.; Sangal, S.P.

1981-01-01

Mixed ligand chelates of the 1:1 trivalent lanthanoids-EDTA, HEDTA and NTA chelates-1, 2-Dihydroxybenzene (Pyrocatechol) have been investigated at 35degC and 0.2 M ionic strength maintained by NaC10 4 . The formation of mixed ligand chelates has been found in all cases. The formation of mixed ligand chelates with EDTA shows the coordination number of lanthanoids to be eight, while the mixed ligand chelates with HEDTA and NTA shows the coordination number to be seven and six respectively. The stability constants of mixed ligand chelates are smaller than the binary complexes. The order of stability constants with respect to primary ligands follows the order NTA>HEDTA>EDTA. With respect to metal ions the stability constants increases with the decrease in ionic radii such as Gd< Er< Yb. (author)

Is DTPA a good competing chelating agent for Th(IV) in human serum and suitable in targeted alpha therapy?

Science.gov (United States)

Le Du, Alicia; Sabatié-Gogova, Andrea; Morgenstern, Alfred; Montavon, Gilles

2012-04-01

The interaction between thorium and human serum components was studied using difference ultraviolet spectroscopy (DUS), ultrafiltration and high-pressure-anion exchange chromatography (HPAEC) with external inductively conducted plasma mass spectrometry (ICP-MS) analysis. Experimental data are compared with modelling results based on the law of mass action. Human serum transferrin (HSTF) interacts strongly with Th(IV), forming a ternary complex including two synergistic carbonate anions. This complex governs Th(IV) speciation under blood serum conditions. Considering the generally used Langmuir-type model, values of 10(33.5) and 10(32.5) were obtained for strong and weak sites, respectively. We showed that trace amounts of diethylene triamine pentaacetic acid (DTPA) cannot complex Th(IV) in the blood serum at equilibrium. Unexpectedly this effect is not related to the competition with HSTF but is due to the strong competition with major divalent metal ions for DTPA. However, Th-DTPA complex was shown to be stable for a few hours when it is formed before addition in the biological medium; this is related to the high kinetic stability of the complex. This makes DTPA a potential chelating agent for synthesis of (226)Th-labelled biomolecules for application in targeted alpha therapy. Copyright © 2011 Elsevier Inc. All rights reserved.