Estudo experimental e te��rico das propriedades magn��ticas e supercondutoras dos compostos borocarbetos da s��rie Y(Ni 1-x Mn x) 2 B2 C com x = 0,0, 0,01, 0,025, 0,05, 0,10 e 0,15

Apresentamos neste trabalho os resultados de um estudo experimental e te��rico dos compostos borocarbetos supercondutores da s��rie Y(Ni1-xMnx)2B2C com x = 0; 0,01; 0,025; 0,05; 0,10; 0,15. A principal motiva����o para este trabalho foi investigar a estrutura eletr��nica e a poss��vel forma����o do momento magn��tico sobre os ��tomos de impureza de Mn nos compostos Y(Ni1- xMnx)2B2C. O aparecimento do momento magn��tico localizado no s��tio da impureza possibilitou estudar a influ��ncia do Mn sobre o mecanismo de quebra de pares supercondutores e sobre as propriedades magn��ticas do composto. Os borocarbetos s��o compostos de estrutura cristalina tetragonal de corpo centrado e altamente anisotr��picos (c/a~3). S��o intermet��licos de alta temperatura cr��tica supercondutora Tc, com forte acoplamento el��tron-fonon. Em alguns casos podem apresentar ordem magn��tica, supercondutividade e tamb��m coexist��ncia ou competi����o energ��tica entre ambos. As medidas de transporte eletr��nico, em fun����o da temperatura, foram feitas utilizando-se um detector s��ncroton baseado na t��cnica de quatro pontos operando na faixa de 4,2K at�� 300K. Essas medidas possibilitaram o estudo das propriedades relacionadas ao transporte eletr��nico na fase supercondutora. Na fase normal, extraiu-se a depend��ncia em energia da fun����o espectral de fonons ���� F (��) para alguns compostos da s��rie estudada. As medidas magn��ticas em fun����o da temperatura e do campo magn��tico foram feitas utilizando-se um SQUID (Superconducting Quantun Interference Device ��� Quantun Design Model MPMS XL). Tais medidas permitiram a caracteriza����o das propriedades magn��ticas de nossas amostras. Em particular determinou-se o valor, em regime de satura����o, do momento magn��tico associado ao s��tio cristalino do Mn. Foram determinadas tamb��m as correntes cr��ticas supercondutoras usando o Modelo de estado cr��tico de Bean e a varia����o da temperatura cr��tica supercondutora (Tc) com a mudan��a do campo externo aplicado. As medidas magn��ticas permitiram a obten����o do diagrama que relaciona o campo cr��tico inferior (HC1) e a temperatura, variando-se a concentra����o do ��tomo dopante de mangan��s. Foi feito um esfor��o te��rico no sentido de interpretar os resultados experimentais. Para isso foram usados tr��s modelos: O modelo de estado cr��tico de Bean j�� citado acima e um modelo baseado na f��rmula de Ziman usando uma aproxima����o para a fun����o espectral de fonons para descrever a resistividade no regime de alta temperatura. Al��m disto, usou-se o modelo de duas sub-redes para a descri����o do momento magn��tico das impurezas de Mn, em fun����o da concentra����o, na s��rie Y(Ni ) ( 2 �� �� F 1-xMnx)2B2C.

Self-assembly of metallosupramolecules directed by (N-H)(2)center dot center dot center dot SCN-M (M = Co, Ni), C-H center dot center dot center dot pi and pi-pi synthons

This work deals with the synthesis, spectroscopic and structural investigation of pyrazolyl complexes of the type trans-[M(NCS)(2)(HPz)(4)] {M=Co (1), Ni (2); HPz=pyrazole}. Single crystal X-ray studies on 1 and 2 reveal the formation of similar supramolecular arrangements derived from self-assembly of monomers linked together through intermolecular N-H center dot center dot center dot SCN hydrogen bonds, C-H center dot center dot center dot pi interactions and pi-pi stacking. (c) 2005 Elsevier B.V. All rights reserved.

Ni(II)-doped CsCdBrCl2: Variation of spectral and structural properties via mixed-halide coordination

A new addition to the family of single-molecule magnets is reported: an Fete cage stabilized with benzoate and pyridonate ligands. Monte Carlo methods have been used to derive exchange parameters within the cage, and hence model susceptibility behavior.

Efeito do teor em Y2O3 nos catalisadores suportados de 8%Ni/��-Al2O3 durante a rea����o de oxida����o parcial do Metano para produ����o de Hidrog��nio

Neste trabalho avaliou-se o desempenho de cinco catalisadores de N��quel suportados em ��-Alumina, com diferentes teores em ��tria, durante a rea����o de Oxida����o Parcial do Metano para a produ����o de Hidrog��nio: 8%Ni/��-Al2O3, 8%Ni/2%Y2O3.��-Al2O3, 8%Ni/2,5%Y2O3.��-Al2O3, 8%Ni/5%Y2O3.��-Al2O3 e 8%Ni/Y2O3. Foram realizados testes catal��ticos numa Unidade de Rea����o acoplada a um equipamento de an��lise, microGC. A rea����o decorreu �� temperatura de 800 ��C, num reator laboratorial de quartzo, durante 18 horas, com uma mistura pura de CH4 e O2 (Condi����o Concentrada). Os resultados demonstraram um aumento de atividade para os catalisadores de suporte misto com maior teor em Y2O3. Usando o mesmo procedimento, a rea����o de OPM foi realizada tamb��m para outra mistura reacional de CH4 e O2, mas agora dilu��da em H��lio (Condi����o Dilu��da). Estes resultados permitiram avaliar a velocidade de rea����o e a atividade dos catalisadores (TOF), para diferentes valores de temperatura, numa situa����o inicial de aus��ncia de coque. Numa segunda etapa, avaliou-se o desempenho dos mesmos materiais durante 2 horas de rea����o �� temperatura constante de 800 ���. Finalmente, atrav��s da t��cnica de carateriza����o de XPS, identificaram-se as esp��cies presentes na superf��cie dos catalisadores. Os resultados sugerem que h�� forma����o de um composto intermedi��rio NiYO3 formado entre o metal e o promotor Y2O3, conferindo atividade e estabilidade aos catalisadores e reduzindo a deposi����o de coque. O catalisador com maior teor em Y2O3 (8%Ni/5%Y2O3.��-Al2O3) foi o mais beneficiado com a adi����o do promotor, demonstrando melhor desempenho para a produ����o de H2 na Rea����o de Oxida����o Parcial do Metano.

Potentiometric determination of Nickel (II) ion using 2-hydroxy-1-naphthylidene-N-cyanoacetohydrazone as electroactive material

A potentiometric Nickel sensor was prepared using 2-hydroxy-1-naphthylidene-N-cyanoacetohydrazone as electro-active material and epoxy resin as a binding material. A membrane composed of 40% Schiff's base and 60% epoxy resin exhibited the best performance. The membrane showed excellent response in the concentration range of 0.15 ppm to 0.1 mol L- 1 Ni+2 ions with non-Nernstian slope of 22.0 mV/decade, had a rapid response time (less than 10 s), and can be used for three months without any considerable loss of potential. The sensor was useful within the pH range of 1.3 to 9.6, and was able to discriminate between Ni2+ and a large number of alkaline earth and transition metal ions. The practical utility of the sensor has been demonstrated by using it successfully as an indicator electrode in the potentiometric titration of Ni2+ with EDTA and oxalic acid.

Nouveaux complexes pinces POCOP, NHCCOP, PIMCOP et PIMIOCOP, et complexes cyclom��tall��s de Ni(II) : synth��se, caract��risation et r��activit��.

Cette th��se traite de la chimie des complexes pinces de Ni(II) ainsi que des complexes cyclom��tall��s de Ni(II) comportant au moins un motif phosphinite. Elle se divise en trois parties. La premi��re concerne la synth��se, la caract��risation, le m��canisme de formation et la r��activit�� des complexes pinces de Ni(II) �� base de ligand de type POCOP 1,3-(i-Pr2PO)2C6H4. De nouveaux ligands de type R-(POCOP) = ��P,��C,��P-{Rn-2,6-( R'2PO)2C6H4-n}; Rn = 4-OMe, 4-Me, 4-CO2Me, 3-OMe, 3- CO2Me, 3,5-t-Bu2 ; R' = i-Pr, t-Bu ont ��t�� synth��tis��s suite �� l'addition de chlorophosphine ClPR'2 �� une solution de r��sorcinol ou d��riv��s en pr��sence de base. La synth��se des complexes R-(POCOP)Ni(Br) s'effectue �� partir du ligand correspondant en pr��sence de base, et de {NiBr2(NCiPr)}n. Ce nouveau pr��curseur de nickel est synth��tis�� �� partir de brome de nickel m��tallique dans l'isobutyronitrile. Il est stable sous atmosph��re inerte et sa solubilit�� dans les solvants polaires permet d'��tudier les synth��ses des complexes en milieu homog��ne. Le m��canisme de formation des complexes portant des ligand pinces (PCsp3P) 1,3-(i- Pr2PCH2CH2)2CH2, (POCsp3OP) 1,3-(i-Pr2POCH2)2CH2, (PCsp2P) 1,3-(i- Pr2PCH2)2C6H4, Rn-(POCsp2OP) 1,3-(i-Pr2PO)2C6H4-n via nickellation du lien C-H a ��t�� investigu�� avec une m��thode de r��action de comp��tition. Cette ��tape a ��t�� d��termin��e comme ��tant de nature ��lectrophile. Les complexes r��sultants ont ��t�� compl��tement caract��ris��s. Une corr��lation a notamment ��t�� effectu��e entre le d��placement chimique du Cipso en spectroscopie RMN 13C et le potentiel d'oxydation Eox en voltam��trie cyclique. Une nouvelle m��thode de synth��se directe verte "one pot" a ��t�� mise en place. En faisant r��agir �� 75 ��C un m��lange h��t��rog��ne de II r��sorcinol, de chlorodiisopropylphosphine et de nickel m��tallique en poudre, on obtient le complexes pince (POCOP)Ni(Cl) avec des rendements allant jusqu'�� 93%. La r��activit�� de ces complexes POCOP a ��t�� investigu��e pour des r��actions de fluorination et trifluorom��thylation des halog��nures d'alkyle. La synth��se du (POCOP)Ni(F) a lieu �� partir de pr��curseur (POCOP)Ni(X) (X=Br, Cl), en pr��sence d'un large exc��s de fluorure d'argent AgF. Ce complexe catalyse la fluorination du bromure de benzyle et peut ��tre converti en (POCOP)Ni(CF3) en pr��sence de r��actif du Ruppert, Me3SiCF3. La r��action entre (POCOP)Ni(CF3) et le bromure de benzyle dans les solvants aromatiques m��ne �� la conversion totale du complexe en (POCOP)Ni(Br) et �� l'inattendue benzylation du solvant aromatique utilis��. La seconde partie concerne la synth��se des nouveaux complexes non sym��triques �� base de ligands comportant un motif imidazolo-phosphine (PIMCOP) 3-[2-(R2P)-C3H2N2]-(R2PO)-C6H3, imidazoliophosphine (PIMIOCOP) 3-[2-(R2P)-3- (CH3)-C3H2N2]-(R2PO)-C6H3] et carb��ne N-h��t��rocyclique (NHCCOP). La double d��protonation du 3-hydroxyphenyl-imidazole suivi de l'addition de deux ��quivalents de chlorodiphenylphosphine m��ne �� l'obtention du ligand PIMCOP 3-[3-(CH3)- C3H2N2]-(R2PO)-C6H3. L'��tape de nickellation a lieu comme dans le cas des compos��s (POCOP)Ni. La m��thylation du motif imidazole du (PIMCOP)Ni(Br) par le triflate de m��thyle MeOTf, donne le d��riv�� (PIMIOCOP)Ni(Br). Ce dernier est converti en (NHCCOP)Ni(Br) apr��s l'addition de chlorure de t��tra��thylamonium NEt4Cl. Les analogues i-Pr2P de ces complexes sont synth��tis��s en rempla��ant ClPPh2 par ClPiPr2. On obtient les esp��ces cationiques [(PIMCOP)Ni(NCCH3)][OTf], [(PIMIOCOP)Ni(NCCH3)][OTf]2 et III [(NHCCOP)Ni(NCCH3)][OTf] suite �� l'addition en solution dans l'ac��tonitrile de triflate d'argent AgOTf. Ces esp��ces ont ��t�� utilis��s comme catalyseurs pour la synth��se d'amidine �� partir de benzonitrile et de diverse amines aliphatiques. Enfin des complexes orthonickell��s trans-Ni[(��2-P,C-P(OC6H4)-(iPr2)( iPr2P(OC6H5))]Br �� base de phosphinite ont ��t�� synth��tis��s et caract��ris��s. Les ligands sont synth��tis��s par r��action d'un ph��nol et de chlorodiisopropylphosphine en pr��sence de base. L'ajout de {NiBr2(NCiPr)}n et de tri��thylamine permet l'orthom��tallation via une ��tape de nickellation C-H. Un interm��diaire trans- [NiBr2{PiPr2(OC6H5)}2] de cette r��action a ��t�� isol��. Le complexe dim��re peut r��agir avec des esp��ces ��lectrophiles mener �� l'ortho-fonctionnalisation de la phosphinite.

Dinuclear complexes of M-II thiocyanate (M = Ni and Cu) containing a tridentate Schiff-base ligand: synthesis, structural diversity and magnetic properties

A dinuclear Ni-II complex, [Ni-2(L)(2)(H2O)(NCS)(2)]center dot 3H(2)O (1) in which the metal atoms are bridged by one water molecule and two mu(2)-phenolate ions, and a thiocyanato-bridged dimeric Cull complex, [Cu(L)NCS](2) (2) [L = tridentate Schiff-base ligand, N-(3-aminopropyl)salicylaldimine, derived from 1:1 condensation of salicylaldehyde and 1,3-diaminopropane], have been synthesized and characterized by IR and UV/Vis spectroscopy, cyclic voltammetry and single-crystal X-ray diffraction studies. The structure of 1 consists of dinuclear units with crystallographic C-2 symmetry in which each Ni-II atom is in a distorted octahedral environment. The Ni-O distance and the Ni-O-Ni angle, through the bridged water molecule, are 2.240(11) angstrom and 82.5(5)degrees, respectively. The structure of 2 consists of dinuclear units bridged asymmetrically by di-mu(1,3)-NCS ions; each Cull ion is in a square-pyramidal environment with tau = 0.25. Variable-temperature magnetic susceptibility studies indicate the presence of dominant ferromagnetic exchange coupling in complex 1 with J = 3.1 cm(-1), whereas complex 2 exhibits weak antiferromagnetic coupling between the Cu-II centers with J = -1.7 cm(-1). ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Two new Ni-II complexes with mu(1.5)-dicyanamide as bridging ligand

One 3D and one 2D mu(1,5)-dicyanamide bridged Ni-II complexes having molecular formula [Ni(L1)(dca)(2)] (1) and [Ni-2(L-2)(2)(dca)(4)] (.) 0.5H(2)O (2) (L1 = 4-(2-aminoethyl)-morpholine, L2 = 1-(2-aminoethyl)-piperidine and dca = dicyanamide dianion) have been synthesized. X-ray single crystal analyses and low temperature magnetic measurements were used to characterize the complexes. Complex 1 represents a 3D structure where each metal ion is chelated by morpholine ligand (L1) and connected by four mu(1,5)-dca. Whereas complex 2 shows an undulated 2D structure with grid of (4,4) topology having two crystallographically independent Ni-II centers in similar octahedral environment where each metal center is chelated by one piperidine ligand (L2) and coordinated by four mu(1,5)-dca. Magnetic measurements of both the complexes indicate weak antiferromagnetic interactions through the mu-(1,5)-dca bridging ligands. (c) 2004 Elsevier B.V. All rights reserved.

Gap junction-mediated spontaneous Ca(2+) waves in differentiated cholinergic SN56 cells

Neuronal gap junctions are receiving increasing attention as a physiological means of intercellular communication, yet our understanding of them is poorly developed when compared to synaptic communication. Using microfluorimetry, we demonstrate that differentiation of SN56 cells (hybridoma cells derived from murine septal neurones) leads to the spontaneous generation of Ca(2+) waves. These waves were unaffected by tetrodotoxin (1microM), but blocked by removal of extracellular Ca(2+), or addition of non-specific Ca(2+) channel inhibitors (Cd(2+) (0.1mM) or Ni(2+) (1mM)). Combined application of antagonists of NMDA receptors (AP5; 100microM), AMPA/kainate receptors (NBQX; 20microM), nicotinic AChR receptors (hexamethonium; 100microM) or inotropic purinoceptors (brilliant blue; 100nM) was also without effect. However, Ca(2+) waves were fully prevented by carbenoxolone (200microM), halothane (3mM) or niflumic acid (100microM), three structurally diverse inhibitors of gap junctions, and mRNA for connexin 36 was detected by PCR. Whole-cell patch-clamp recordings revealed spontaneous inward currents in voltage-clamped cells which we inhibited by Cd(2+), Ni(2+) or niflumic acid. Our data suggest that differentiated SN56 cells generated spontaneous Ca(2+) waves which are propagated by intercellular gap junctions. We propose that this system can be exploited conveniently for the development of neuronal gap junction modulators.

Ni catalysts with Mo promoter for methane steam reforming

NiO/Al(2)O(3) catalyst precursors were prepared by simultaneous precipitation, in a Ni:Al molar ratio of 3:1, promoted with Mo oxide (0.05, 0.5, 1.0 and 2.0 wt%). The solids were characterized by adsorption of N(2), XRD, TPR, Raman spectroscopy and XPS, then activated by H(2) reduction and tested for the catalytic activity in methane steam reforming. The characterization results showed the presence of NiO and Ni(2)AlO(4) in the bulk and Ni(2)AlO(4) and/or Ni(2)O(3) and MoO(4)(-2) at the surface of the samples. In the catalytic tests, high stability was observed with a reaction feed of 4:1 steam/methane. However, at a steam/methane ratio of 2: 1, only the catalyst with 0.05% Mo remained stable throughout the 500 min of the test. The addition of Mo to Ni catalysts may have a synergistic effect, probably as a result of electron transfer from the molybdenum to the nickel, increasing the electron density of the catalytic site and hence the catalytic activity. (C) 2009 Elsevier Ltd. All rights reserved.

Spectroscopic studies on glassy Ni(II) and Co(II) polyphosphate coacervates

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

S��ntese e caracteriza����o de compostos de coordena����o do ��cido 4-cloro-2-(2- furilmetilamino)-5- sulfamoil-benz��ico com os ��ons n��quel, cobalto e zinco

This work aimed to promote the synthesis, characterization and propose a plausible molecular structure for coordination compounds involving furosemide (4-Chloro-2-(2- furylmethylamino)-5-sulfamoyl-benzoic acid) with the metal ions Ni+2, Zn+2 and Co+2. The compounds were obtained in methanoic medium by evaporation of the solvent after the synthesis procedure. For characterization of coordination compounds determining the levels of metals by EDTA complexometry, infrared spectroscopy (FTIR), solubility of compounds in various solvents, thermogravimetry (TG), differential scanning calorimetry (DSC), differential thermal analysis were made (DTA), determination of the carbon , hydrogen and nitrogen (CHN). The results of infrared spectroscopy in the region suggest that the organic ligand is coordinated in a bidentate fashion to the metal ions, the metal center interactions to occur by the coordination of the nitrogen atom of the amino group and the oxygen atom of the carboxylic acid of the structure of furosemide. With the results of the levels of metal, elemental analysis (CHN) and thermal analysis has been possible to propose the structure of the ligand. The values of the molar conductivity of the complex in acetonitrile behavior suggest the non acetonitrile electrolyte solution. With the solubility tests it was found that the compounds have high solubility in methanol and acetonitrile, as are partially insoluble in water. From the results of thermal analysis (TG, DSC, DTA), it was possible to obtain the thermal behavior of the compounds as stages of dehydration, thermal stability, decomposition and the energies involved.

LEACHATE TREATMENT PROCESS AT A MUNICIPAL STABILIZED LANDFILL BY CATALYTIC OZONATION: AN EXPLORATORY STUDY FROM TAGUCHI ORTHOGONAL ARRAY

Catalytic ozonation has been recognized in the scientific community as an efficient technique, reaching elevated rates of recalcitrant organic material mineralization, even at the presence of scavenger species of hydroxyl free radicals. This study presents the most significant factors involving the leachate treatment stabilized by the municipal landfill of the city of Guaratingueta, State of Sao Paulo, Brazil, by using a catalytic ozonation activated by metallic ions Fe(3+), Zn(2+), Mn(2+), Ni(2+) and Cr(3+). The Taguchi L(16) orthogonal array and its associated statistical methods were also used in this study. Among the researched ions, the most notable catalysis was obtained with ferric ion, statistically significant in the reduction of COD with a confidence level of 99.5%.

Nickel adsorption in two Oxisols and an Alfisol as affected by pH, nature of the electrolyte, and ionic strength of soil solution

Background, aim, and scope The retention of potentially toxic metals in highly weathered soils can follow different pathways that variably affect their mobility and availability in the soil-water-plant system. This study aimed to evaluate the effects of pH, nature of electrolyte, and ionic strength of the solution on nickel (Ni) adsorption by two acric Oxisols and a less weathered Alfisol. Materials and methods The effect of pH on Ni adsorption was evaluated in surface and subsurface samples from a clayey textured Anionic `Rhodic` Acrudox ( RA), a sandy-clayey textured Anionic `Xantic` Acrudox (XA), and a heavy clayey textured Rhodic Kandiudalf (RK). All soil samples were equilibrated with the same concentration of Ni solution (5.0 mg L(-1)) and two electrolyte solutions (CaCl(2) or NaCl) with different ionic strengths (IS) (1.0, 0.1 and 0.01 mol L(-1)). The pH of each sample set varied from 3 to 10 in order to obtain sorption envelopes. Results and discussion Ni adsorption increased as the pH increased, reaching its maximum of nearly pH 6. The adsorption was highest in Alfisol, followed by RA and XA. Competition between Ni(2+) and Ca(2+) was higher than that between Ni(2+) and Na(+) in all soil samples, as shown by the higher percentage of Ni adsorption at pH 5. At pH values below the intersection point of the three ionic strength curves (zero point of salt effect), Ni adsorption was generally higher in the more concentrated solution (highest IS), probably due to the neutralization of positive charges of soil colloids by Cl(-) ions and consequent adsorption of Ni(2+). Above this point, Ni adsorption was higher in the more diluted solution (lowest ionic strength), due to the higher negative potential at the colloid surfaces and the lower ionic competition for exchange sites in soil colloids. Conclusions The effect of ionic strength was lower in the Oxisols than in the Alfisol. The main mechanism that controlled Ni adsorption in the soils was the ionic exchange, since the adsorption of ionic species varied according to the variation of pH values. The ionic competition revealed the importance of electrolyte composition and ionic strength on Ni adsorption in soils from the humid tropics. Recommendations and perspectives The presence of NaCl or CaCl(2) in different ionic strengths affects the availability of heavy metals in contaminated soils. Therefore, the study of heavy metal dynamics in highly weathered soils must consider this behavior, especially in soils with large amounts of acric components.

Solubility of Epiphany Endodontic Sealer Prepared with Resinous Solvent

Purpose: To evaluate in vitro the solubility of the Epiphany endodontic filling material Epiphany (Pentron Clinical Technologies, Wallingford, CT) prepared with its resinous solvent. Methods: The specimens were prepared in the following experimental conditions: (1) GI, epiphany without photoactivation; (2) GII, Epiphany prepared with resinous solvent without photoactivation; (3) Gill, Epiphany followed by photoactivation; and (4) GIV, Epiphany prepared with resinous solvent followed by photoactivation. Ten specimens of each group were obtained from Teflon molds with 80% reduction in volume of the specimen`s dimensions based on American National Standard Institute/American Dental Association (ANSI/ADA) Specification No. 57. The samples were weighted and immersed in distilled water for 7 days. After this period, they were removed, dried, and weighed again. Solubility was calculated by using samples weight loss (%). The immersion liquid was evaluated through atomic absorption spectrometry. Results: The sealers without photoactivation were statistically similar (p > 0.05) between themselves (GI = 6.93% and GII = 6.39%) and different from the uncured sealers, which were statistically different between themselves (p < 0.05) (GIII = 3.56% and GIV = 0.47%). Only the Epiphany sealer prepared with resinous solvent followed by photoactivation presented solubility values within ANSI/ADA requirements, liberating the following amounts of ions: 114.43 mu g of Ca(2+)/mL, 2.4 mu g of Mg(2+)/mL, 0.33 mu g of Fe(2+)/mL, 0.11 mu 4g of Zn(2+)/mL, 1.31 mu g of Ni(2+)/mL, and 7.1 mu g of Na(+)/mL. Conclusion: The association of resinous solvent to the Epiphany sealer followed by photoactivation resulted in a filling material with low solubility and expressive liberation of calcium ions. (J Endod 2009;35:715-718)