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Bonding
Kinds of Bonding Terms modified by Bonding Selected AbstractsOPTIONS FOR DENTIN/ENAMEL BONDING: PART IIIJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 3 2010Associate Editor Edward J. Swift Jr. DMD, Author Four categories of resin-based dentin/enamel adhesives are currently available. These include the three-step etch-&-rinse, "one-bottle" etch-&-rinse, two-step self-etch primer systems, and "all-in-one" self-etch adhesives. In consecutive issues of the Journal, the Critical Appraisal series is presenting salient publications on research in each of the categories. The first two installments focused on the etch-&-rinse systems. The series continues with this review of papers on the two-step self-etch primer systems. [source] OPTIONS FOR DENTIN/ENAMEL BONDING: PART IIJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2010Associate Editor, Edward J. Swift Jr., MS Author Four categories of resin-based dentin/enamel adhesives are currently available. These include the three-step etch-and-rinse, "one-bottle" etch-and-rinse, two-step self-etch primer systems, and "all-in-one" self-etch adhesives. In consecutive issues of the journal, the Critical Appraisal series will present salient publications on research in each of the categories. The first installment focused on the three-step etch-and-rinse systems and the series continues with this paper on the one-bottle etch-and-rinse systems. [source] BONDING TO FLUOROSED TEETHJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 4 2009PhD Guest Experts, R. Banu Ermis DDS [source] RESIN BONDING TO CERAMICJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2008PhD Guest Expert, Raymond L. Bertolotti DDS [source] OPTIONS FOR DENTIN BONDINGJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2006Claus-Peter Ernst Prof. Dr. med. dent. First page of article [source] Bonding of fractured permanent central incisor crown following radiographic localization of the tooth fragment in the lower lip: a case reportDENTAL TRAUMATOLOGY, Issue 5 2010Gabriela Ferrari Da Silva Schwengber The trauma also resulted in a cut on his mentum. Radiographic examination revealed the fractured tooth fragment embedded in the lower lip. The fractured tooth, with incomplete root formation, was treated endodontically and received a temporary restoration. After 15 days, the temporary restoration was removed and the fractured tooth fragment was etched with 37% phosphoric acid. A bonding system was then applied to the etched-fractured tooth surface without polymerization. The same bonding procedure was carried out on the tooth fragment. A layer of flowable resin composite was applied to the fragment, which was positioned on the remaining tooth. The resin composite was then polymerized, finished, and polished. [source] Pair Bonding and Multiple Paternity in the Polygamous Common Quail Coturnix coturnixETHOLOGY, Issue 4 2003J. D. Rodríguez-Teijeiro The common quail (Coturnix coturnix) is one of the few species in which mate-switching (when different pair bonds are established within a single breeding attempt), has been recorded. In this study, we report the characteristics of pair bonds (description, number of males per female and duration) by monitoring a wild population of common quail (28 females and 49 males) by radiotracking. 57% of the females studied (n = 14) showed mate-switching, whereas 22% of the males were serially polygynous, successively forming pairs with a series of females. The fitness of females with mate-switching, measured in terms of clutch size and hatching success, did not differ from that of females bonded with one male. The analysis of paternity in three families by multilocus DNA fingerprinting revealed genetic polygamy in two of the nests studied. A male sired offspring with two females, and we obtained genetic evidence for intraspecific brood parasitism. We discuss how these behavioural and ecological observations may relate to the particular mating system of the common quail. [source] New Approaches to 12-Coordination: Structural Consequences of Steric Stress, Lanthanoid Contraction and Hydrogen BondingEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2010Anthony S. R. Chesman Abstract The anionic dinitrile ligand dicyanonitrosomethanide (dcnm), C(CN)2(NO),, and the anion resulting from its addition product with water, carbamoylcyanonitrosomethanide (ccnm), C(CN)(CONH2)(NO),, have been incorporated into lanthanoid complexes and display unusual ,2(N,O) nitroso coordination modes. (Et4N)3[Ln(ccnm)6] (1Ln; 1Ln = 1La, 1Ce, 1Pr, 1Nd, 1Sm) and (Me4N)3[Ln(ccnm)6] (2Ln; 2Ln = 2La, 2Ce, 2Pr, 2Nd) are systems containing 12-coordinate homoleptic trianionic lanthanoidate complexes. The nitroso groups of the ccnm ligands form three-membered ring chelates with the lanthanoid metal centre, with the asymmetry of the nitroso ,2 interactions dependent upon the intramolecular N,H···O=N hydrogen bonding. Additional intermolecular hydrogen bonding interactions exist between adjacent amide and nitrile groups giving rise to 3D ,-Po and 6,8-connected (412.63)(420.68) networks in 1Ln and 2Ln, respectively. The compounds (Me4N)3[Ln(dcnm)6] (3Ln; 3Ln = 3La, 3Ce, 3Nd, 3Sm) also contain a 12-coordinate trianionic lanthanoidate complex with the nitroso group exhibiting a highly symmetrical ,2 interaction. The sterically crowded environments of [Ln(18-crown-6)(dcnm)3] (4Ln; 4Ln = 4La, 4Ce, 4Pr, 4Nd) result in a shift towards a more asymmetric ,2 bonding of the nitroso group with decrease in the Ln3+ radius. There is a corresponding increase of the Ln,O,N angle, and one ligand is ,1(O) binding in 4Nd. The dcnm ligands in the discrete complexes [La(phen)3(dcnm)(3,x)Clx], x , 0.25 (5) (phen = 1,10-phenanthroline), (Et4N)[Ce(phen)2(dcnm)4] (6a/b, 6c) and [Ce(phen)2(dcnm)Cl2H2O] (7) display a variety of coordination modes. Complex 5 has 1D chains formed by ,,, stacking of adjacent phen co-ligands. Complexes 6 contain the monoanionic complex [Ce(phen)2(dcnm)4], with two geometric isomers present in the crystal structure of 6a/b. Complex 7 forms extended 1D chains via hydrogen bonding between coordinated water and chloride atoms and an extensive array of face-to-face , interactions. [source] Aluminium Complexes of a Phenoxyimine Ligand with a Pendant Imidazolium Moiety: Synthesis, Characterisation and Evidence for Hydrogen Bonding in SolutionEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 35 2008Stefano Milione Abstract Novel alkylaluminium complexes (phim)AlMe2 (1) and(phimid)AlR2+Br, [R = Me (2), R = iBu (3)] bearing the Schiff base ligands 3,5- tBu2 -2-(OH)C6H2CH=NiPr (phim -H) and3,5- tBu2 -2-(OH)C6H2CH=NCH2CH2[CH(NCHCHNiPr)]Br(phimid -H·Br) have been prepared and fully characterised. Complexes 1,3 each have a tetrahedral structure, with the aluminium atom surrounded by the oxygen and nitrogen atoms of the chelating ligand and two alkyl groups. The structures of phimid -H·Br and of complex 1 have been determined by X-ray diffraction studies. Investigation of the solution structures of 1,3 by 1H NMR spectroscopy revealed that the coordinated phimid ligand is involved in hydrogen bonding with bromide anion. Treatment of 1 with B(C6F5)3 led smoothly to (phim)Al(C6F5)Me (4) by transfer of a C6F5 group from MeB(C6F5)3, to the initially formed coordinatively unsaturated cationic intermediate. In contrast, treatment of 2 with one equiv. of B(C6F5)3 afforded the cationic monomethyl species (phimid)AlMeBr+,MeB(C6F5)3, (5), stabilised by the coordination of the bromide anion acting as a Lewis base.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Variability in the Structures of Luminescent [2-(Aminomethyl)pyridine]silver(I) Complexes: Effect of Ligand Ratio, Anion, Hydrogen Bonding, and ,-StackingEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2005Rodney P. Feazell Abstract The reaction of 2-(aminomethyl)pyridine (2-amp) with silver(I) salts of triflate (OTf,), trifluoroacetate (tfa,), and tetrafluoroborate (BF4,) produce monomeric, dimeric, bridged, and polymeric structural motifs. The structural characteristics are dependent upon the ratio of ligand/metal in the structure as well as the ability of the anion to coordinate to the metal centers and form hydrogen bonds to the bound ligands. The silver coordination environment takes on several geometries including near linear (6), trigonal (4), tetrahedral (1), and both trigonal-bipyramidal and square-based pyramidal in a single structure (2). Structures 2, 3, and 5 also display short Ag,Ag contacts ranging from 2.8958(3) to 3.0305(4) Å. The species with metal,metal interactions, which are connectively very similar to their metal-isolated counterparts of 1, 4, and 6, are held together only by weak ,-stacking interactions or hydrogen bonds to their respective anions. Low-temperature luminescence spectra were collected for all compounds and are compared. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Novel Bonding Modes between Tetrathiafulvalenes (TTFs) and Transition Metal Centers: ,-Bonding and Covalent TTFSiMe2,MLn Coordination to PlatinumEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2004Mathuresh N. Jayaswal Abstract Two novel strategies for coordinating TTF to transition metal centers have been developed. The reaction of tetrathiafulvalene (TTF) or 3,4-dimethyltetrathiafulvalene (o -Me2TTF) with [Pt(,2 -C2H4)(PPh3)2] leads to the , complexes [Pt(,2 -TTF)(PPh3)2] (1) and [Pt(,2 - o -Me2TTF)(PPh3)2] (2), respectively. An X-ray crystallographic study performed on 2 confirmed, that TTFs act as a , acidic ligand. NMR studies revealed the existence, in solution, of an equilibrium between free and complexed TTF. Dilithiation of o -Me2TTF and subsequent silylation with ClSiMe2H afforded 3,4-dimethyl-3,,4,-(dimethylsilyl)tetrathiafulvalene (3), which has been structurally characterized. 3 reacts by oxidative addition across [Pt(,2 -C2H4)(PPh3)2] to give [Pt{,2 - o -(SiMe2)2TTFMe2}(PPh3)2] (4), in which the TTF ligand is covalently ligated to platinum via SiMe2 bridges. The redox properties of 3 and 4 have been investigated by cyclic voltammetry. Strong cathodic shifts of the two redox processes were observed for 4, implying the TTF core. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Calculated Enthalpies for Dimerisation of Binary, Unsaturated, Main-Group Element Hydrides as a Means to Analyse Their Potential for Multiple BondingEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2003Hans-Jörg Himmel Abstract Herein, the dimerisation of subvalent, binary, main-group element hydrides with the potential for multiple bonding is studied using both hybrid DFT (B3LYP) and ab initio [MP2 and CCSD(T)] methods. The [2+2] cycloaddition is an important and characteristic reaction of derivatives of ethylene. A comparison of dimerisation reactions for several compounds with the potential for multiple bonding should, therefore, shed light on the properties of these species. Our study includes the hydrides E2H2 (E = B, Al, Ga, N P or As), E2H4 (E = C, Si or Ge) and ENH4 (E = B, Al or Ga) and their dimers. Several isomeric forms of the monomers and dimers have to be considered. The trends within a group and a period are established and the factors responsible for them are discussed. It turns out that, generally, the enthalpies for dimerisation increase for heavier homologues, reflecting that the most important factor is the reduced strength of the E,E bonds in the monomers prior to dimerisation and, to some degree, also the reduced ring strain in the cyclic dimers. The exceptions are the dimerisations of B2H2 and Al2H2, both of which lead to the tetrahedral E4H4 species (E = B or Al). Dimerisation of Al2H2 is associated with a smaller enthalpy than that for the dimerisation of B2H2. Comparisons and analyses are made complicated because of the changes in the structures of the isomeric global minima between homologues. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Tailoring Materials Properties by Accumulative Roll Bonding,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Tina Hausöl Accumulative roll bonding (ARB) as a method of severe plastic deformation (SPD) is an interesting established process to produce ultrafine-grained (UFG) sheet materials with high potential for light weight constructions. The ARB process offers a high flexibility for tailored material design. Al2O3 particles, carbon fibers and titanium foils are used as reinforcement of aluminum sheets introduced during accumulative roll bonding. Furthermore multicomponent materials are produced by cladding of different aluminum alloys. These sandwich-like structures allow to combine desired properties of the materials involved. Post-ARB heat treatment offers another possibility for tailoring materials properties of graded structures as shown by formation of TiAl3 in Al/Ti laminates. The tailored materials are investigated by means of SEM, EDX, nanoindentation experiments and tensile testing. [source] Enol Forms of 1,3-Indanedione, Their Stabilization by Strong Hydrogen Bonding, and Zwitterion-Assisted InterconversionEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2010Mark Sigalov Abstract By analyzing NMR spectroscopic data, and supported by IR, UV/Vis, Raman, dielectrometry, and DFT techniques, a comprehensive study of the 1:2 adducts of picolinaldehyde and 1,3-indanediones is presented. The parent indanedione derivative 5 exists in an equilibrium between all-keto and enol forms, the latter being stabilized by an intramolecularO,H···N hydrogen bond. Only the all-keto form was observed in the 5,6-dimethoxy compound 6, whereas solely the enol tautomer was observed with its 5,6-dichloro analogue 7. Polar solvents and low temperatures shift the equilibrium towards the enol tautomer in 5. The structure of adduct 8, formed with isonicotinaldehyde, prevents the formation of intramolecular O,H···N hydrogen bonds and thus it exists in the all-keto form in low polar solvents. However, in DMSO solutions it adopts a zwitterionic form with a strong anionic O,···H···O hydrogen bond. Thus, the enol form in indanedione adducts was unequivocally characterized in solution and the factors that determine the keto,enol tautomerism, namely electronic effects, solvent, temperature, and intramolecular hydrogen bonds, have been methodically studied by spectroscopic and quantum mechanical methods. [source] Bonding of a Silorane-Based Composite System to BoneADVANCED ENGINEERING MATERIALS, Issue 11 2009Xiaohong Wu This work was to analyze by Weibull statistics the shear bond strength of a low-shrink Silorane-based composite system to bone. The etching abilities of the adhesives were investigated by scanning electron microscopy. Results suggest that an effective and reliable bond to bone could be achieved by the Silorane-based composite system, showing the potential of this system to be used as a bone cement. [source] Deslipping of Ester Rotaxanes: A Cooperative Interplay of Hydrogen Bonding with Rotational BarriersEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2003Petra Linnartz Abstract A series of rotaxanes has been synthesized which contain two ester groups in their axles. All rotaxanes bear the same tetralactam wheel. The kinetics of the de-slipping reaction of these rotaxanes were monitored in tetrachloroethane (TCE) and dimethyl sulfoxide (DMSO) resulting in the observation of a significant solvent effect. In TCE, two isomeric rotaxanes that differ merely with respect to the orientation of the ester groups show a remarkable difference in their deslipping behavior. When the ester carbonyl group is directly attached to the axle center piece, the rotaxane decomposes with a half life of ca. 10 h at 100 °C. The reverse orientation with the carbonyl group attached to the stopper blocks deslipping almost completely and a lower limit for the half life at 100 °C of 25,000 h was obtained. These results can be interpreted by inferring a cooperative action of hydrogen bonding between wheel and axle and differences in rotational barriers. Molecular modeling and AM1 calculations support this interpretation. The implications of these results for the determination of steric size and the optimization of molecular machines are discussed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Evaluation of Transient Liquid Phase Bonding Between Titanium and SteelADVANCED ENGINEERING MATERIALS, Issue 7 2009Ahmed Elrefaey An investigation of microstructural development in transient liquid phase (TLP) bonds between commercially pure titanium and low carbon steel is presented in this study. Changes in the joint region and surrounding substrates were examined as a function of holding time at temperatures of 870 and 910 °C. Both interfacial microstructures and mechanical properties of brazed joints were investigated to evaluate joint quality. [source] Enhanced Strength and Ductility in Ultrafine-Grained Aluminium Produced by Accumulative Roll Bonding,ADVANCED ENGINEERING MATERIALS, Issue 9 2004H.W. Höppel Due to a printing error in the Adv. Eng. Mater. 2004, 6, issue 4, this article, originally published on pages 219,222, had to be reprinted. Now the correct references are given to allow all readers the correct access to the literature. The editorial team apologizes for any inconveniences this may have caused. [source] Strong Carbon-Nanotube,Polymer Bonding by Microwave Irradiation,ADVANCED FUNCTIONAL MATERIALS, Issue 12 2007Y. Wang Abstract The vigorous response of multiwalled carbon nanotubes (MWNTs) to microwave irradiation, leading to the release of a large amount of heat, is used to locally melt a plastic matrix adjacent to the nanotubes within a period of seconds. This results in the intercalation of the MWNTs into the polymer matrix at room temperature without any physical damage to the polymer. The so-called "microwave welding" approach creates a new paradigm for the formation of very strong MWNT,polymer bonds without the use of any adhesive, and represents a significant step forward for the fabrication of functional nanotube composites. Here, we demonstrate the implications of the anisotropic alignment of MWNTs in polymers, patterned conductors/resistors for soft electronics, and high-strength composites, where the MWNTs are ,soldered' to flexible polymer substrates. [source] Hydrogen Bonding of Fluorinated Saccharides in Solution: F Acting as H-Bond Acceptor in a Bifurcated H-Bond of 4-Fluorinated Levoglucosans,HELVETICA CHIMICA ACTA, Issue 10 2007Bruno Bernet Abstract 4-Fluorinated levoglucosans were synthesised to test if OH,,,F H-bonds are feasible even when the O,,,F distance is increased. The fluorinated 1,6-anhydro- , - D -glucopyranoses were synthesised from 1,6,:,3,4-dianhydro- , - D -galactopyranose (8). Treatment of 8 with KHF2 and KF gave 43% of 4-deoxy-4-fluorolevoglucosan (9), which was transformed into the 3- O -protected derivatives 13 by silylation and 15 by silylation, acetylation, and desilylation. 4-Deoxy-4-methyllevoglucosan (19) and 4-deoxylevoglucosan (21) were prepared as reference compounds that can only form a bivalent H-bond from HOC(2) to OC(5). They were synthesised from the iPr3Si-protected derivative of 8. Intramolecular bifurcated H-bonds from HOC(2) to FC(4) and OC(5) of the 4-fluorinated levoglucosans in CDCl3 solution are evidenced by the 1H-NMR scalar couplings h1J(F,OH) and 3J(H,OH). The OH,,,F H-bond over an O,,,F distance of ca. 3.0,Å is thus formed in apolar solvents, at least when favoured by the simultaneous formation of an OH,,,O H-bond. [source] Solvent-Assisted Decal Transfer Lithography by Oxygen-Plasma Bonding and Anisotropic SwellingADVANCED MATERIALS, Issue 22 2010Pilnam Kim Solvent-assisted decal transfer lithography (DTL) enables the formation of well-defined micro-/nanostructures over a large area (,4 in. wafer) by combining irreversible oxygen bonding and anisotropic swelling of poly(dimethoxylsiloxane) (PDMS). Such swelling-induced stress gradient allows for cohesion failure of the skin layer upon removal of the stamp, leaving behind a highly uniform layer (,100,nm). [source] Imaging and Spectroscopy of Multiwalled Carbon Nanotubes during Oxidation: Defects and Oxygen Bonding (Adv. Mater.ADVANCED MATERIALS, Issue 19 200919/2009) Photoelectron spectromicroscopy studies revealed the morphology changes and the abundance of various oxygenated functional groups on individual multiwalled carbon nanotubes exposed to oxidizing environments. Alexei Barinov and co-workers show on page 1916 that carbonyl type bonding configurations prevail when fragmentation and extinction of the nanotubes occur. [source] Imaging and Spectroscopy of Multiwalled Carbon Nanotubes during Oxidation: Defects and Oxygen BondingADVANCED MATERIALS, Issue 19 2009Alexei Barinov The gasification process, which increases the number of broken CC bonds and the abundance of particular oxygenated functional groups, is shown to destroy carbon nanotubes (CNTs). The expansion of the defect density and dimensions leads to nonlinear consumption of the CNTs with increasing O dose. Some nanotubes are consumed faster than others, most probably due to higher defect densities. [source] Supramolecular Organization of ssDNA-Templated ,-Conjugated Oligomers via Hydrogen BondingADVANCED MATERIALS, Issue 10-11 2009Mathieu Surin The templated self-assembly of water-soluble ,-conjugated molecules bearing a diaminotriazine moiety H-bonding to a single-strand oligothymine template leads to defined structures. We study these assemblies with molecular modeling, circular dichroism spectroscopy, and scanning probe microscopy, to get a better understanding of the factors governing the supramolecular organization and structural order. [source] Layered Double Hydroxide Surface Modified with (3-aminopropyl)triethoxysilane by Covalent Bonding,ADVANCED MATERIALS, Issue 1 2005A.-Y. Park Interlayer surfaces of layered double hydroxide (LDH) have been functionalized with amine moieties by condensation between the hydroxyl groups and (3-aminopropyl)triethoxysilane (APS) molecules via the covalent oxane bonds M-O-Si (M=Zn and Cr) (see Figure). Since the galleries of the modified LDHs have a hydrophobic field, various functional molecules such as enzymes, catalysts, and organic molecules can be incorporated between the LDH layers. [source] Bonding and correlation analysis of various Si2CO isomers on the potential energy surfaceINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 5 2009Zhong-Jun Zhou Abstract At various levels of theory, singlet and triplet potential energy surfaces (PESs) of Si2CO, which has been studied using matrix isolation infrared spectroscopy, are investigated in detail. A total of 30 isomers and 38 interconversion transition states are obtained at the B3LYP/6-311G(d) level. At the higher CCSD(T)/6-311+G(2d)//QCISD/6-311G(2d)+ZPVE level, the global minimum 11 (0.0 kcal/mol) corresponds to a three-membered ring singlet O-cCSiSi (1A,). On the singlet PES, the species 12 (0.2 kcal/mol) is a bent SiCSiO structure with a 1A, electronic state, followed by a three-membered ring isomer Si-cCSiO (1A,) 13 (23.1 kcal/mol) and a linear SiCOSi 14 (1,+) (38.6 kcal/mol). The isomers 11, 12, 13, and 14 possess not only high thermodynamic stabilities, but also high kinetic stabilities. On the triplet PES, two isomers 31 (3B2) (18.8 kcal/mol) and 37 (3A,) (23.3 kcal/mol) also have high thermodynamic and kinetic stabilities. The bonding natures of the relevant species are analyzed. The similarities and differences between C3O, C3S, SiC2O, and SiC2S are discussed. The present results are also expected to be useful for understanding the initial growing step of the CO-doped Si vaporization processes. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Cover Picture: Bidentate Ligands by Self-Assembly through Hydrogen Bonding: A General Room Temperature/Ambient Pressure Regioselective Hydroformylation of Terminal Alkenes (Adv. Synth.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-13 2005Catal. Abstract The cover picture shows a typical industrial reaction, hydroformylation of terminal alkenes, made possible in a test tube with ambient pressure and room temperature with high regioselectivities. For more details, see the Communication by Wolfgang Seiche, Alexander Schuschkowski, and Bernhard Breit on pages 1488,1494. [source] The Influence of Time Interval between Bleaching and Enamel BondingJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2007Jéfferson Da Silva Machado dds ABSTRACT Objectives:, The purpose of this study was to investigate the penetration of a conventional adhesive material into enamel bleached with 16% carbamide peroxide and 38% hydrogen peroxide using optical light microscopy. Methods:, Extracted human teeth were randomly divided into eight experimental groups with six specimens each, according to the bleaching material and time interval after bleaching and before the bonding procedure. Groups were designated as follows: control group, restorations in unbleached teeth; restorations performed immediately after bleaching; restorations performed 7 days after bleaching; restorations performed 14 days after bleaching; and restorations performed 30 days after bleaching. The length of resin tags was measured with an Axiophot photomicroscope at 400× magnification for the calculation of the proportion of tags of study groups compared to the respective control groups. Analysis of variance was applied for comparison between groups; data were transformed into arcsine (p < 0.05). Results:, The specimens of experimental groups, in which restorations were performed 7, 14, and 30 days after bleaching, showed better penetration of adhesive material into enamel than specimens restored immediately after bleaching. There was no statistically significant difference between the bleaching materials employed or in the interaction between bleaching agent and time interval. Conclusions:, This suggests that a time interval of at least 7 days should be allowed between enamel bleaching and placement of adhesive bonding agents for accomplishment of composite resin restorations. CLINICAL SIGNIFICANCE Establishment of adequate time after bleaching is fundamental to allow the normal penetration of a one-bottle conventional adhesive onto the enamel surface. [source] Parental Bonding and Adult Attachment Styles in Different Types of Stalker,JOURNAL OF FORENSIC SCIENCES, Issue 6 2008Rachel D. MacKenzie D.Psych. Abstract:, Attachment theory is one of the earliest and most vigorously promoted explanations of the psychological processes that underlie stalking behavior. Insecure attachment has been proposed as impairing the management of relationships, thus increasing the propensity to stalk. The current study explored the parental bonding and adult attachment styles of 122 stalkers referred to a specialist forensic clinic. Stalkers were grouped according to two common classification methods: relationship and motivation. Compared to general community samples, stalkers were more likely to remember their parents as emotionally neglectful and have insecure adult attachment styles, with the degree of divergence varying according to stalker type and mode of classification. In offering support for the theoretical proposition that stalking evolves from pathological attachment, these findings highlight the need to consider attachment in the assessment and management of stalkers. Also emphasized is the importance of taking classification methods into account when interpreting and evaluating stalking research. [source] Engineering functional materials by halogen bondingJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2007Pierangelo Metrangolo Abstract Engineering functional materials endowed with unprecedented properties require the exploitation of new intermolecular interactions, which can determine the characteristics of the bulk materials. The great potential of Halogen Bonding (XB), namely any noncovalent interaction involving halogens as electron acceptors, in the design of new and high-value functional materials is now emerging clearly. This Highlight will give a detailed overview on the energetic and geometric features of XB, showing how some of them are quite constant in most of the formed supramolecular complexes (e.g., the angle formed by the covalent and the noncovalent bonds around the halogen atom), while some others depend strictly on the nature of the interacting partners. Then, several specific examples of halogen-bonded supramolecular architectures, whose structural aspects as well as applications in fields as diverse as enantiomers' separation, crystal engineering, liquid crystals, natural, and synthetic receptors, will be fully described. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: PolymChem 45: 1,15, 2007 [source] | |||||||||||||||||||||||||||||||||||||||||||||||||