Comparative in vivo study of commercially pure Ti implants with surfaces modified by laser with and without silicate deposition: Biomechanical and scanning electron microscopy analysis

The purpose of this study was to evaluate commercially pure titanium implant surfaces modified by laser beam (LS) and LS associated with sodium silicate (SS) deposition, and compare them with machined surface (MS) and dual acid-etching surfaces (AS) modified. Topographic characterization was performed by scanning electron microscopy-X-ray energy dispersive spectroscopy (SEM-EDX), and by mean roughness measurement before surgery. Thirty rabbits received 60 implants in their right and left tibias. One implant of each surface in each tibia. The implants were removed by reverse torque for vivo biomechanical analysis at 30, 60, and 90 days postoperative. In addition, the surface of the implants removed at 30 days postoperative was analyzed by SEM-EDX. The topographic characterization showed differences between the analyzed surfaces, and the mean roughness values of LS and SS were statistically higher than AS and MS. At 30 days, values removal torque LS and SS groups showed a statistically significant difference (p < 0.05) when compared with MS and AS. At 60 days, groups LS and SS showed statistically significant difference (p < 0.05) when compared with MS. At 90 days, only group SS presented statistically higher (p < 0.05) in comparison with MS. The authors can conclude that physical chemistry properties and topographical of LS and SS implants increases bone-implant interaction and provides higher degree of osseointegration when compared with MS and AS. © 2012 Wiley Periodicals, Inc.

Low temperature X-ray structures of two crystalline forms (I) and (II) of the pyrimidine derivative and sodium channel blocker BW1003C87: 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine

The X-ray crystal structures of two crystalline forms of 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine, C10H7Cl3N4 (code name BW1003C87) (I) and (II), have been carried out at liquid nitrogen temperature. A detailed comparison of the two structures is given. Both are centrosymmetric, with structure (I) in the triclinic space group P (1) over bar unit cell a = 6.4870(10), b = 9.216(2), c = 12.016(2) angstrom, alpha = 75.78(3)degrees, beta = 89.95(3)degrees, gamma = 83.45(3)degrees, V = 691.5(2) angstrom(3), Z = 2 and density (calculated) = 1.544 Mg/m(3); and (II) in the monoclinic space group P2(1)/c, unit cell a = 12.000(2), b = 7.518(2), c = 13.450(3) angstrom, beta = 97.87(3)degrees, V = 1202.0(5) angstrom(3), Z = 4, Density (calculated) = 1.600 Mg/m(3). Structure (I) includes a solvated CH3OH in the lattice. Final R indices [I > 2sigma(I)] are R1 = 0.0427, wR2 = 0.1075 for (I) and R1 = 0.0487, wR2 = 0.1222 for (II). R indices (all data) are R1 = 0.0470, wR2 = 0.1118 for (I) and R1 = 0.0623, wR2 = 0.1299 for (II). 5-Phenyl-2,4 diaminopyrimidine and 6-phenyl-1,2,4 triazine derivatives, which include lamotrigine (3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine), have been investigated for some time for their effects on the central nervous system. Both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW1003C87), the subject of the present study, are anticonvulsant as well as neuroprotective in models of brain ischaemia and in a model of white matter ischaemia. BW1003C87 is a sodium channel blocker which also reduces the release of the neurotransmitter glutamate. The three dimensional structures reported here form part of a newly developed data base for the detailed investigation of members of this drug family and their biological activities.

Influence of enamel matrix derivative (Emdogain((R))) and sodium fluoride on the healing process in delayed tooth replantation: histologic and histometric analysis in rats

Although it has already been shown that enamel matrix derivative (Emdogain((R))) promotes periodontal regeneration in the treatment of intrabony periodontal defects, there is little information concerning its regenerative capacity in cases of delayed tooth replantation. To evaluate the alterations in the periodontal healing of replanted teeth after use of Emdogain((R)), the central incisors of 24 Wistar rats (Rattus norvegicus albinus) were extracted and left on the bench for 6 h. Thereafter, the dental papilla and the enamel organ of each tooth were sectioned for pulp removal by a retrograde way and the canal was irrigated with 1% sodium hypochlorite. The teeth were assigned to two groups:in group I, root surface was treated with 1% sodium hypochlorite for 10 min (changing the solution every 5 min), rinsed with saline for 10 min and immersed in 2% acidulated-phosphate sodium fluoride for 10 min; in group II, root surfaces were treated in the same way as described above, except for the application of Emdogain((R)) instead of sodium fluoride. The teeth were filled with calcium hydroxide (in group II right before Emdogain((R)) was applied) and replanted. All animals received antibiotic therapy. The rats were killed by anesthetic overdose 10 and 60 days after replantation. The pieces containing the replanted teeth were removed, fixated, decalcified and paraffin-embedded. Semi-serial 6-mu m-thick sections were obtained and stained with hematoxylin and eosin for histologic and histometric analyses. The use of 2% acidulated-phosphate sodium fluoride provided more areas of replacement resorption. The use of Emdogain((R)) resulted in more areas of ankylosis and was therefore not able to avoid dentoalveolar ankylosis. It may be concluded that neither 2% acidulated-phosphate sodium fluoride nor Emdogain((R)) were able to prevent root resorption in delayed tooth replantation in rats.

Tb3+ sensitization in a deoxycholate organogel matrix, and selective quenching of luminescence by an aromatic nitro derivative

In this article, we present the discovery of a metallo-organogel derived from a Tb3+ salt and sodium deoxycholate (NaDCh) in methanol. The gel was made luminescent through sensitization of Tb3+ by doping with 2,3-dihydroxynaphthalene (DHN) in micromolar concentrations. Rheological measurements of the mechanical properties of the organogel confirmed the characteristics of a true gel. Significant quenching of Tb3+ luminescence was observed in the deoxycholate gel matrix by 2,4,7-trinitrofluorenone (TNF), but not by several other polynitro aromatics. Microscopic studies (AFM, TEM and SEM) revealed a highly entangled fibrous network. The xerogels retained luminescent properties suggesting the possibility for application in coatings, etc.

Synergistic extraction of rare earths using acid-base coupling extractants of calix[4]arene carboxyl derivative and primary amine N1923

Synergistic effect in the extraction of rare earth (RE) metals by the acid-base coupling (ABC) extractants of calix[4]arene carboxyl derivative Bu-t[4]CH2COOH (H(4)A) and primary amine N1923 (RNH2) has been investigated. The extraction of RE was enhanced by the addition of sodium cations into the aqueous phase not only in the extraction system of Bu-t[4]CH2COOH alone but also in the mixture of Bu-t[4]CH2COOH and N1923. The separation factors (SFs) indicating the extraction selectivity of adjacent RE elements became higher in the mixture system.

Electrochemical recognition of alkali metal ions at the micro-water 1,2-dichloroethane interface using a calix[4]arene derivative

In this paper, a calix[4]arene derivative, 5,11,17,23-butyl-25,26,27,28-tetra-(ethanoxycarbonyl)-methoxy-calix[4]arene (L), is investigated as a host to recognize alkali metal ions (Li+, Na+, K+, Rb+ and Cs+) at the interface between two immiscible electrolyte solutions (ITIES). Well-defined cyclic voltammograms are obtained at the micro- and nano-water \ 1,2-dichloroethane (W \ DCE) interfaces supported at micro- and nano-pipets.

Alkali metal ions transfer across a water/1,2-dichloroethane interface facilitated by a novel monoaza-B15C5 derivative

In this paper, a novel monoaza-B15C5 derivative, N-(2-tosylamino)-isopentyl-monoaza-15-crown-5 (L), is used as an ionophore to facilitate alkali metal cations transfer across a water/1,2-dichloroethane (W/DCE) interface. Well-defined voltammetric behaviors are observed at the polarized W/DCE interfaces supported at micro- and nano-pipets except Cs+. The diffusion coefficient of this ionophore in the DCE phase is calculated to be equal to (3.3+/-0.2) x 10(-6) cm(2) s(-1). The experimental results indicate that a 1:1 (metal: ionophore) complex is formed at the interface with a TIC/TID mechanism. The selectivity of this ionophore towards alkali ions follows the sequence Na+ > Li+ > K+ > Rb+ > Cs+. The logarithm of the association constants (log beta(1)(0)) of the LiL+, NaL+, KL+ and RbL+ complexes in the DCE phase are calculated to be 10.6, 11.6, 9.0 and 7.1, respectively. The kinetic parameters are determined by steady-state voltammograms using nanopipets. The standard rate constants (k(0)) for Li+, Na+, K+ and Rb+ transfers facilitated by L are 0.54+/-0.05, 0.63+/-0.09, 0.51+/-0.04 and 0.46+/-0.06 cm s(-1), respectively. The pH values of aqueous solution have little effect on the electrochemical behaviors of these facilitated processes. The results predicate that this new type of ionophore might be useful to fabricate electrochemical sensor of sodium ion.

SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF A MONOPENTAMETHYLCYCLOPENTADIENYL DERIVATIVE OF GADOLINIUM (NA(MU-2-THF)[(C5ME5)GD(THF)]2(MU-2-CL)3(MU-3-CL)2)2.6THF

The reaction of GdCl3 with 1 equiv of NaC5Me5 generates a neutral complex C5Me5GdCl2(THF)3 and a novel complex {Na(mu-2-THF)[(C5Me5)Gd(THF)]2(mu-2-Cl)3(mu-3-Cl)2}2.6THF whixh recrystallizes from THF in triclinic, the space group P1BAR with unit cell dimentions of a 12.183(4), b 13.638(6), c 17.883(7) angstrom, alpha-110.38(3), beta-94.04(3), gamma-99.44(3)-degrees, V 2721.20 angstrom-3 and D(calc) 1.43 g cm-3 for Z = 1. Least-squares refinement of 2170 observed reflections led to a final R value of 0.047. The title complex consists of two Na(mu-2-THF)[(C5Me5)Gd(THF)]2(mu-3-Cl)3(mu-3-Cl)2 units bridged together via two mu-2-THF to Na coordination. Each Gd ion is surrounded by one C5Me5 ligand, two mu-3-Cl, two mu-2-Cl and one THF in a distorted octahedral arrangement with average Gd-C(ring) 2.686(33), Gd-mu-2-Cl 2.724(7), Gd-mu-3-Cl 2.832(8) and Gd-O 2.407(11) angstrom. The sodium ion coordinates to two bridging THF, two mu-2-Cl and two mu-3-Cl to form a distorted octahedron with average Na-mu-2-O, Na-mu-2-Cl and Na-mu-3-Cl of 2.411(21), 2.807(15) and 2.845(12) angstrom, respectively.

Conformational and hydration effects of site-selective sodium, calcium and strontium ion binding to the DNA Holliday junction structure d(TCGGTACCGA)(4)

The role of metal ions in determining the solution conformation of the Holliday junction is well established, but to date the picture of metal ion binding from structural studies of the four-way DNA junction is very incomplete. Here we present two refined structures of the Holliday junction formed by the sequence d(TCGGTACCGA) in the presence of Na+ and Ca2+, and separately with Sr2+ to resolutions of 1.85 Angstrom and 1.65 Angstrom, respectively. This sequence includes the ACC core found to promote spontaneous junction formation, but its structure has not previously been reported. Almost complete hydration spheres can be defined for each metal cation. The Na+ sites, the most convincing observation of such sites in junctions to date, are one on either face of the junction crossover region, and stabilise the ordered hydration inside the junction arms. The four Ca2+ sites in the same structure are at the CG/CG steps in the minor groove. The Sr2+ ions occupy the TC/AG, GG/CC, and TA/TA sites in the minor groove, giving ten positions forming two spines of ions, spiralling through the minor grooves within each arm of the stacked-X structure. The two structures were solved in the two different C2 lattices previously observed, with the Sr2+ derivative crystallising in the more highly symmetrical form with two-fold symmetry at its centre. Both structures show an opening of the minor groove face of the junction of 8.4degrees in the Ca2+ and Na+ containing structure, and 13.4degrees in the Sr2+ containing structure. The crossover angles at the junction are 39.3degrees and 43.3degrees, respectively. In addition to this, a relative shift in the base pair stack alignment of the arms of 2.3 Angstrom is observed for the Sr2+ containing structure only. Overall these results provide an insight into the so-far elusive stabilising ion structure for the DNA Holliday junction. (C) 2003 Elsevier Science Ltd. All rights reserved.

Synthesis and thermal studies of solid state 2-chloro-benzylidenepyruvic acid and its compounds with sodium, aluminium (III), gallium (III) and indium (III) cations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In vitro antimicrobial efficiency of a mouthwash containing triclosan/gantrez and sodium bicarbonate

Several antiseptic substances have been used as adjuncts to routine mechanical procedures of oral hygiene, based on their antimicrobial effects. The objective of this study was to assess in vitro the antimicrobial efficiency of 2 mouthwash containing Triclosan/Gantrez and sodium bicarbonate in comparison to both positive and negative controls. Standard strain samples of Escherichia coli, Pseudomonas aeruginosa, Actinomyces viscosus and Bacillus subtilis were used. Samples of Streptococcus mutans and Gram-negative bacilli were collected from 20 volunteers (10 with a clinically healthy periodontium and 10 presenting biofilm-associated gingivitis). Evaluation of the antimicrobial activity was performed by determining the minimal inhibitory concentration (MIC). The results indicated that the test solution inhibited the growth of both Gram-negative and Gram-positive microorganisms from the volunteers' saliva as well as that of the standard strains at the MIC dilution of 1:20, whereas the MIC dilution of 0.12% chlorhexidine against the same bacteria was 1:80. Thus, even though the tested mouthrinse solution presented an in-vitro antimicrobial activity superior to that of a placebo, it was inferior to that of chlorhexidine.

Employing perichromism for probing the properties of carboxymethyl cellulose films: an expedient, accurate method for the determination of the degree of substitution of the biopolymer derivative

The properties of films of carboxymethyl cellulose, CMC, of different degree of substitution, DS, have been examined by the use of perichromic indicators (probes). The film properties that have been determined are: empirical polarity, E-T(33); "acidity", alpha; "basicity", beta; and dipolarity/polarizability, pi*. This has been achieved by employing the following perichromic probes: 4-nitroaniline, 4-nitroanisole, 4-nitro-N,N-dimethylaniline, and 2,6-dichloro-4-(2,4,6-triphenyl-pyridinium-1-yl)phenolate, WB. The correlations between both E-T(33)- or pi* and DS were found to be linear; that between beta and DS is a second order polynomial; no obvious correlation was found between alpha and DS. The polarities of CMC films are in the range of those of butyl alcohols. As models for CMC, we have employed cellulose plus CMC of high DS; oxidized cellulose with degree of oxidation = 0.5; sodium glucuronate. The former model behaved akin to CMC, but the plots of the perichromic properties versus DS showed different slopes/intercepts. FTIR data and molecular dynamics simulations on the solvation of WB have shown that this difference can be traced to more efficient hydrogen bonding between the film of the model and the probe. This affects the intra-molecular charge-transfer energy of the latter, leading to different responses to the variation of DS. Based on the excellent linear correlation between E-T(33) and DS, for CMC from different origins, we suggest that perichromism is a simple, accurate, and expedient alternative for the determination of DS of the biopolymer derivative.