177,233 research outputs found
Dataset supplementing the publication "Spaeth K., Nawaz Q., Schilling T., Goetz-Neunhoeffer F., Detsch R., Boccaccini A. R., Hurle K. - New Insights into application relevant properties of Cu2 - doped brushite cements"
No full textCollectivity of all measured data mentioned in the article “Spaeth, K., Nawaz Q., Schilling T., Goetz-Neunhoeffer F., Detsch R., Boccaccini A. R., Hurle K. - New Insights into application relevant properties of Cu2+- doped brushite cements". Listed are raw data of the following methods: Antibacterial tests (Hemmhof tests), compressive strength measurements, cytotoxicity tests (cell viability by optical density and fluorescence microscopy images), injectability measurements, ionic release by inductively coupled plasma - mass spectrometry, pH measurements, scanning electron microscopy images, setting time measurements and powder X-ray diffraction. Some results are only presented in german
MONOMER AND DIMER 1,3-DIAZA-2-PHOSPHAALLYLLITHIUM COMPLEXES - STRUCTURES AND AMBIDENT REACTIVITY
No full textDETSCH R, NIECKE E, NIEGER M, Schoeller W. MONOMER AND DIMER 1,3-DIAZA-2-PHOSPHAALLYLLITHIUM COMPLEXES - STRUCTURES AND AMBIDENT REACTIVITY. CHEMISCHE BERICHTE-RECUEIL. 1992;125(5):1119-1124.Metallation of the NH-functional amino(imino)phosphanes Mes*NPNHR (R = CPh3, Ad, tBu) 1a-c yields the 1,3-diaza-2-phosphaallyllithium compounds 2a-c. The crystal structure shows an ether-stabilized monomer of 2a and a solvent-free dimer with an eight-membered ring in the case of 2b,c. The reaction of 2b with chlorodiphenylphosphane yields, dependent on the reaction conditions, (phosphanylamino)iminophosphane 3 or bis(imino)phosphanylphosphorane 4. The structural and reactivity is discussed on the basis of ab initio calculations
Waste derived glass ceramic composites prepared by low temperature sintering/sinter-crystallisation
No full textGlass-ceramics based on iron rich wastes were produced by direct sintering and by following an innovative approach, combining direct sintering and sinter-crystallisation processes. According to the second method, a layered tile was manufactured by single firing at 9008C using a selected combination of wastes for both the porous body and the dense coating layer. The coating layer ('glaze') results from the sinter-crystallisation of a waste derived glass mixed with zircon and recycled borosilicate glass. The glaze sealed the porosity of the body and enhanced both mechanical properties and chemical stability. The results show a near to zero water absorption rate, despite a low geometric density (∼2 g cm-3), accompanied by a Young's modulus of ∼40 GPa and a bending strength of ∼30 MPa. The chemical stability of the glass-ceramics thus developed was assessed by the application of a toxicity control leaching procedure. Furthermore, cell culture tests were carried out to evaluate the potential cytotoxicity of the material
FROM COVALENT TO IONIC BONDING - SPONTANEOUS BOND-DISSOCIATION IN OXY-SUBSTITUTED IMINOPHOSPHANES
No full textNIECKE E, DETSCH R, NIEGER M, REICHERT F, Schoeller W. FROM COVALENT TO IONIC BONDING - SPONTANEOUS BOND-DISSOCIATION IN OXY-SUBSTITUTED IMINOPHOSPHANES. BULLETIN DE LA SOCIETE CHIMIQUE DE FRANCE. 1993;130(1):25-31.According to quantum chemical theory, structural changes in the PN double bond of iminophosphanes are strongly influenced by the electronic properties of sigma-push-pull substituents. This concept is strongly operative in oxy-substituted iminophosphanes, RO-P=N-Mes*, 2a-g, (R = silyl, organyl, and organosulfonyloxy; Mes* = 2,4,6-tBu3C6H2), which are synthesized by nucleophilic substitution of the chloro(aryl)iminophosphane 1 and structurally elucidated. The PO bond lengths vary from 1.585 (R = SiMe3) to 1.923 pm (R = CF3CSO2) indicating spontaneous PO bond dissociation in the latter
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
45S5 Bioglass®-derived scaffolds coated with organic–inorganic hybrids containing graphene
No full textHighly porous 45S5 Bioglass®-based scaffolds fabricated by a foam replication technique were coated with electrically conductive organic-inorganic hybrid layers containing graphene by a solution method. α,ω- Triethoxysilane terminated poly (ethylene glycol) and tetraethoxysilane were used as the precursors of the organic-inorganic hybrid coatings, that contained 1.5 wt.% of homogeneously dispersed graphene nanoplatelets. The resulting coated scaffolds retained their original high porosity and interconnected pore structure after coating. The presence of graphene did not impair the bioactivity of the scaffolds in simulated body fluid. Initial tests carried out using MG-63 cells demonstrated that both uncoated scaffolds and scaffolds coated with organic/inorganic hybrids containing graphene offered the cultured cells an adequate surface for cell attachment, spreading and expression of extracellular matrix. The results showed that scaffolds coated with graphene are biocompatible and they can support cellular activity. The electrical conductivity introduced by the coating might have the potential to increase tissue growth when cell culture is carried out under an applied electric field
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Highly Porous Polymer-Derived Bioceramics Based on a Complex Hardystonite Solid Solution
No full textHighly porous bioceramics, based on a complex hardystonite solid solution, were developed from silicone resins and micro-sized oxide fillers fired in air at 950 °C. Besides CaO, SrO, MgO, and ZnO precursors, and the commercial embedded silicone resins, calcium borate was essential in providing the liquid phase upon firing and favouring the formation of an unprecedented hardystonite solid solution, corresponding to the formula (Ca0.70Sr0.30)2(Zn0.72Mg0.15Si0.13) (Si0.85B0.15)2O7. Silicone-filler mixtures could be used in the form of thick pastes for direct ink writing of reticulated scaffolds or for direct foaming. The latter shaping option benefited from the use of hydrated calcium borate, which underwent dehydration, with water vapour release, at a low temperature (420 °C). Both scaffolds and foams confirmed the already-obtained phase assemblage, after firing, and exhibited remarkable strength-to-density ratios. Finally, preliminary cell tests excluded any cytotoxicity that could be derived from the formation of a boro-silicate glassy phase
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