Search results for "visual_art"
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Dithiosquarate (dtsq) complexes of nickel(II). Syntheses and crystal structures of [Ni(phen)2(1,2-dtsq)]·3.5H2O, [Ni(phen)2(1,3-dtsq)] and [Ni(tren)(…
2003
Abstract The new nickel(II) complexes [Ni(phen)2(1,2-dtsq)]·3.5H2O (1), [Ni(phen)2(1,3-dtsq)] (2) and [Ni(tren)(1,2-dtsq)] (3) [1,2-dtsq=dianion of 3,4-dimercapto-3-cyclobutene-1,2-dione, 1,3-dtsq=dianion of 3-hydroxy-4-mercapto-2-thioxo-3-cyclobuten-1-one, phen=1,10-phenanthroline and tren=tris(2-aminoethyl)amine] have been synthesized and characterized by single-crystal X-ray diffraction. Their structures are made up of neutral [Ni(phen)2(1,n-dtsq)] [1 (n=2) and 2 n=3)] and [Ni(tren)(1,2-dtsq)] (3) mononuclear units. The nickel atom is six-coordinated in all three cases: four nitrogen atoms from two bidentate phen (1 and 2) or a tetradentate tren (3) groups and either two sulfur (1 and 3)…
Syntheses, structural characterisation and magnetic properties of Fe(ii) and Mn(ii) compounds with the pentacyanopropenido ligand; structural charact…
2006
International audience; Reactions between the metal(II) salts [M(CH3CN)n](BF4)2 (M = Fe, n = 6; M = Mn, n = 4) and some organic anionic polynitriles were studied. With the pentacyanopropenide anion pcp− [pcp− = (NC)2CC(CN)C(CN)2−], were obtained, according to the experimental conditions, the new complexes [M(pcp)2(H2O)4] (1, M = Fe; 2, M = Mn) and [M(pcp)2] (3, M = Fe; 4 = Mn). Use of the hexacyano-3,4-diazahexadienediide anion [(NC)2CC(CN)NNC(CN)C(CN)22−] instead of pcp− did not afford polynitrile metal complexes but led to a new organic derivative 5, of formula C10N8H2. Crystallographic studies indicated that the isostructural compounds 1 and 2 involve discrete monomeric units with pcp li…
Influence of tetrahedral distortion of CuN4 complexes on spectroscopic properties. Synthesis, characterization and crystal structures of [Cu(N-(2-met…
2001
Abstract A series of new N-sulfonamide ligands and their copper(II) complexes, [Cu(N-(2-methylpyridyl)toluenesulfonylamidate)2] (1), [Cu(N-(2-methylpyridyl)benzenesulfonylamidate)2] (2) and [Cu(N-(2-methylpyridyl)naphthalenesulfonylamidate)2] (3), have been synthesized and characterized. Single crystal X-ray analysis of the three complexes revealed that all of them present a tetracoordinate CuN4 chromophore. The ligands act as bidentate, coordinating the metal ion through the pyridine and sulfonamido N atoms. The main structural difference among the compounds is the varied degree of distortion of square-planar stereochemistry. Complex 1 exhibits a regular square-planar geometry. In complexe…
In vitro analysis of the pH stability of dental bleaching gels during in-office procedures
2021
Background Previous studies have shown that acidic bleaching gels could lead to worse collateral effects during an in-office bleaching procedure, while neutral or basic products leads towards a better experience. Considering this fact, the main purpose of this study was to evaluate the pH behavior of 6 in-office bleaching gels, compared to the information provided by their manufacturers. Material and methods Thirty enamel discs of bovine teeth were prepared, the initial colors of which were measured by a spectrophotometer and then divided into 6 groups. A pH meter was used to measure the pH every 30 seconds until the end of each procedure, when a new color evaluation was then made. The Tuke…
Effect of different protective agents on enamel erosion: An in vitro investigation
2019
Background The purpose of this in vitrostudy was to compare the effect of different protective agents on enamel erosion by measuring mean percentage weight loss. Material and Methods Extracted teeth were sectioned into uniform slabs and enamel specimens were randomly distributed to different groups. Initial weight of all enamel specimens was registered. The protective agents used in this study were Tooth Mousse, MI Paste Plus, Remin Pro and Remin Pro Forte. A control group was treated just with tap water. All the specimens were immersed in Coca-Cola for a total of 8 min at room temperature, dried and weighed. Enamel dissolution caused by acidic soft drink was analyzed: specimens were weighe…
Compositional and microhardness findings in tooth affected by X-linked hypophosphatemic rickets
2020
Background This study aimed to evaluate the X-linked hypophosphatemic rickets (XLHR)-related compositional and microhardness tooth aspects. Material and Methods One affected and one non-affected teeth by XLHR were sectioned transversely, and each section was separated for Micro-Raman spectroscopy, Knoop microhardness and scanning electron microscopy with energy dispersive x-ray microanalysis (SEM-EDS). The outcomes of these analyses were assessed. Results Outcomes of Raman analysis of inorganic/organic components (~958/~1250+~1450 cm−1) and carbonate/phosphate (~1070/~958 cm−1) ratios showed areas of altered enamel and dentin (interglobular dentin, calcospherites, and mantle dentin) with an…
Acid-induced rearrangement of epoxygermacra-8,12-olides: synthesis and absolute configuration of guaiane and eudesmane derivatives from artemisiifolin
2010
A study on the acid-induced rearrangement of 4,5-epoxy- and 1,10-epoxygermacra-8,12-olides was carried out. From a 4,5-epoxy derivative, guaianes were obtained, whereas 1,10-epoxy derivatives furnished, depending on the stereochemistry of the C-1/C-10 epoxy ring, trans-5β,10α- or trans-5α,10β-eudesmanolides.
Linking design management skills and design function organization: An empirical study of Spanish and Italian ceramic tile producers
2007
Abstract Design management is an increasingly important concept, research into which is very scarce. This paper deals with the fit between design management skills and design function organization, ranging from solely in-house to solely outsourced and including a mixture of the two. We carried out a survey in the Spanish and Italian ceramic tile industry, to which 177 product development managers responded. Our results revealed that companies have different degrees of design management skills depending on the approach to design function organization. Solely in-house design approach companies are the most skilled firms and solely outsourced ones are the least skilled. Despite the fact that t…
Gas-chromatographic elemental analysis via di(trifluorethyl)dithiocarbamato-chelates
1986
The capillary-gas-chromatographic conditions for the determination of trace metals after extraction from aqueous solution are optimized by coupling of capillaries and improvement of injection technique. Different detectors (FID and ECD) are tested. pH range and buffer systems for extraction of metal chelates are discussed.
The volatile inventory (F, Cl, Br, S, C) of magmatic apatite: An integrated analytical approach
2012
Abstract Apatite is ubiquitous in a wide range of magmatic rocks and its F–Cl–Br–S systematics can be used to decipher e.g., mixing processes within a magmatic complex and may give insights into fluid un-mixing and degassing processes during the emplacement and cooling of plutonic rocks. In this study, we analyzed a F-apatite (Durango, Mexico), a Cl-apatite (Odegarden, Norway) and apatites from five plutonic samples from the alkaline Mt. Saint Hilaire Complex (Canada) by means of Electron Microprobe Analysis (EPMA), Laser Ablation ICP-MS (LA-ICP-MS), Secondary Ion Mass Spectrometry (SIMS), pyrohydrolysis combined with ion chromatography, Fourier Transformed Infrared Spectroscopy (FTIR), Ins…