480 research outputs found
Effect of modifications of dual acid‐etched implant surfaces on peri‐implant bone formation. Part I: organic coatings
No full textThe aim of the present study was to test the hypothesis that peri-implant bone formation can be improved by modifying dual acid-etched (DAE) implant surfaces using organic coatings that enhance cell adhesion and osteogenic differentiation. Ten adult female foxhounds received experimental titanium implants in the mandible 3 months after removal of all premolar teeth. Six types of implants were evaluated in each animal: (i) implants with a machined surface (MS), (ii) implants with a DAE surface topography, (iii) implants with an acid-etched surface coated with RGD peptides, (iv) implants with an acid-etched surface coated with collagen I, (v) implants with an acid-etched surface coated with collagen I and chondroitin sulphate (CS), (vi) implants with an acid-etched surface coated with collagen I and CS and recombinant human bone morphogenetic protein-2. Peri-implant bone regeneration was assessed by histomorphometry after 1 and 3 months in five dogs each by measuring bone implant contact (BIC) and the bone volume density (BVD) of the newly formed peri-implant bone. After 1 month, mean BIC was significantly higher in the coated implants group than in the MS group. There was no significant difference when mean BIC in the DAE group was compared with implants with any of the organic coatings, but the difference was significant when compared with the MS implants. Differences in mean BVD value did not reach significance between any of the surfaces. After 3 months, the same held true for the mean BIC of all the groups except for Coll I. Mean volume density of the newly formed bone was higher in all the surface modifications, albeit without statistical significance. It is concluded that with the exception of Coll I, the tested organic surface coatings on DAE surfaces did not improve peri-implant bone formation when compared with the DAE surfaces but enhanced BIC when compared with the MSs. To cite this article:Schliephake H, Aref A, Scharnweber D, Bierbaum S, Sewing A. Effect of modifications of dual acid-etched implant surfaces on peri-implant bone formation. Part I: Organic coatings.Clin. Oral Impl. Res. 20, 2009; 31-37.BMBF [03N4021
Harald Bierbaum / Peter Euler / Katrin Feld / Astrid Messerschmidt / Olga Zitzelsberger (Hrsg.): Nachdenken in Widersprüchen. Gernot Koneffkes Kritik bürgerlicher Pädagogik. Wetzlar: Büchse der Pandora 2007 (182 S.) [Rezension]
No full textRezension von: Harald Bierbaum / Peter Euler / Katrin Feld / Astrid Messerschmidt / Olga Zitzelsberger (Hrsg.): Nachdenken in Widersprüchen. Gernot Koneffkes Kritik bürgerlicher Pädagogik. Wetzlar: Büchse der Pandora 2007 (182 S.; ISBN 978-3-88178-328-6; 14,00 EUR)
Bierbaum, Harald / Bünger, Carsten / Kehren, Yvonne / Klingovsky, Ulla (Hg.): Kritik – Bildung – Forschung. Pädagogische Orientierungen in widersprüchlichen Verhältnissen. Opladen: Barbara Budrich 2014 [Rezension]
No full textRezension von: Harald Bierbaum / Carsten Bünger / Yvonne Kehren / Ulla Klingovsky (Hrsg.): Kritik – Bildung – Forschung. Pädagogische Orientierungen in widersprüchlichen Verhältnissen. Opladen: Barbara Budrich 2014 (296 S.; ISBN 978-3-8474-0137-7; 38,00 EUR)
The behavioural ecology of optimism: judgement bias and foraging under predation risk in mice
No full textBračić M, Bierbaum L, Peng M, et al. The behavioural ecology of optimism: judgement bias and foraging under predation risk in mice. Animal Behaviour. 2025;219: 122991
Effect of immobilized bone morphogenic protein 2 coating of titanium implants on peri-implant bone formation
No full textThe aim of the present study was to test the hypothesis that immobilization of bone morphogenic protein (BMP2) on the surface of titanium implants can enhance peri-implant bone formation. Ten adult female foxhounds received experimental titanium screw implants in the mandible 3 months after removal of all premolar teeth. Three types of implant surfaces were evaluated in each animal: (i) implants with machined titanium surface, (ii) implants coated with collagen I, (iii) implants coated with collagen I, chondroitin sulphate (CS) and BMP2. Peri-implant bone regeneration was assessed using histomorphometry after 1 and 3 months in five dogs each by measuring bone-implant contact (BIC) and the volume density of the newly formed peri-implant bone (BVD). After 1 month, there was no significant enhancement in BIC values but volume density of the newly formed peri-implant bone was significantly higher in the two groups of coated implants. No significant difference was found between collagen and BMP2 coating. After 3 months, BIC was significantly higher in both collagen and BMP2-coated implants compared with implants with machined surfaces. Peri-implant BVD was also significantly increased in coated implants in comparison with machined surfaces. It was concluded that collagen coating of dental screw implants can enhance BIC and peri-implant bone formation. Addition of BMP2 does not increase peri-implant bone formation in the present application
Leonhardt, George S. (Death, 1905-05-02)
No full textAddress: 1576 Jones St.Age at death: 22 yrs.Pg 57/1905/109/M W S/Ky./Dr. F. H. Bierbaum/Busse & Borgmann/EvergreenOriginal record filed in drawer labeled 'Leonhard-Lewis, P'
Modifications of Hyaluronan Influence the Interaction with Human Bone Morphogenetic Protein-4 (hBMP-4).
No full textn this study, we have demonstrated that the modification of hyaluronan (hyaluronic acid; Hya) with sulfate groups led to different binding affinities for recombinant human bone morphogenetic protein-4 (rhBMP-4). The high-sulfated sHya2.8 (average degree of sulfation (D.S.) 2.8) exhibited the tightest interaction with rhBMP-4, followed by the low-sulfated sHya1.0, as determined with surface plasmon resonance (SPR), ELISA, and competition ELISA. Unmodified Hya, chondroitin-sulfate (CS), and heparan sulfate (HS) showed significantly less binding affinity. SPR data could be fitted to an A + B = AB Langmuir model and binding constants were evaluated ranging from 13 pM to 5.45 microM. The interaction characteristics of the differentially sulfated Hyas are promising for the incorporation of these modified polysaccharides in bioengineered coatings of biomaterials for medical applications
Dissociative excitation transfer in the reaction of O-2(a(1)Delta(g)) with OH-(H2O)(1,2) clusters.
No full textRate constants for the dissociation of OH-(H2O) and OH-(H2O)(2) by transfer of electronic energy from O-2(a(1)Delta(g)) were measured. Values of 1.8x10(-11) and 2.2x10(-11) cm(3) molecule(-1) s(-1), respectively, at 300 K were derived and temperature dependences were obtained from 300 to 500 K for OH-(H2O) and from 300 to 400 K for OH-(H2O)(2). Dissociative excitation transfer with OH-(H2O) is slightly endothermic and the reaction appears to have a positive temperature dependence, but barely outside the uncertainty range. In contrast, the reaction of OH-(H2O)(2) is exothermic and appears to have a negative temperature dependence. The rate constants are analyzed in terms of unimolecular rate theory, which suggests that the dissociation is prompt and is not affected by collisions with the helium buffer gas
Deuterium kinetic isotope effects in the gas-phase S N2 reactions of solvated fluoride ions with methyl halides
No full textRate constants and deuterium kinetic isotope effects (KIEs) are measured for gas-phase nucleophilic substitution (S(N)2) reactions of solvated fluoride ions of F-(methanol) + CH3X (X = Br, I), F-(isopropyl alcohol) + CH3I, and F-(hydrogen fluoride) + CH3I at 300 K. The isotope effects are determined as the rate constant ratio k(H)/k(D) for specifically deuterated reactants, that is, methanol (CH3OH, CD3OH, CH3OD, and CD3OD), isopropyl alcohol (i-C3H7OH and i-C3H7OD), hydrogen fluoride (HF and DF), and methyl halides (CH3X and CD3X). The data reveal identical trends to those previously observed for F-(water) + CH3X (O'Hair, R. A. J.; Davico, G. E.; Hacaloglu, J.; Dang, T. T.; DePuy, C. H.; Bierbaum, V. M. J. Am. Chern. Soc. 1994, 116, 3609). The S(N)2 reactivities decrease as reaction exothermicity decreases (CH3I > CH3Br > CH3Cl) and as the nucleophile is solvated. Moderate inverse kinetic isotope effects (k(H)/k(D) < 1) are observed for the deuteration of the rnethyl halide, whereas substantial inverse KIEs are measured for the deuteration of the hydroxyl group of the solvent (or the deUteration of hydrogen fluoride). Moderate inverse KIEs are also measured for the deuteration of the methyl group in methanol. The observed trends and magnitudes of the isotope effects are rationalized qualitatively in terms of the S(N)2 transition-state structure and bonding interactions analogous to those in the F-(H2O) + CH3X system
- …
