Objective: To elucidate relationships between the dental roots and surrounding tissues in order to prevent complications after placement of a miniscrew. Materials and Methods: Twenty human mandibles and maxillas were used for this study. In the 200 sections of each mandible and maxilla, nine items were measured to investigate the relationships between the dental roots. Results: The interroot distance increased from anterior to posterior teeth and from the cervical line to the root apex in both the maxilla and the mandible. In the maxilla, the greatest interroot distance was between the second premolar and the first molar. In the mandible, the greatest interroot distance was between the first and second molars. The maxillary buccolingual bone width exceeded 10 mm from 7 mm (between canine and first premolar), 5 mm (between second premolar and first molar), and 4 mm (between first and second molars) above the cervical line. The mandibular buccolingual bone width exceeded 10 mm from 7 mm (between second premolar and first molar) and 4 mm (between first and second molars) below the cervical line. Conclusions:The safest zone for placement of a miniscrew in the maxilla was between the second premolar and the first molar, from 6 to 8 mm from the cervical line. The safest zone for placement of a miniscrew in the mandible was between the first and second molars, less than 5 mm from the cervical line. (Angle Orthod. 2009;79:37-45.)

Bimetallic catalysts have been the subject of numerous studies during the last decades (Sachtler et al., 1961). Particularly, it has been interesting when the metal itself active in a catalytic reaction was modified or promoted with a second metal that also had activity in the same reaction. Addition of a small amount of a second metal is a way to increase the selectivity of the system to alkenes (Sarkany et al., 1995; Monteiro et al., 1995). Both the hydrogen availability and the strength of diene complexation can be modified by the addition of a second metal, thereby improving the selectivity of alkene formation and extending the lifetime of the catalyst. The bimetallic catalysts allow a larger degree of freedom to tune the reaction sites for optimum activity and selectivity. The consequent changes in activity and selectivity are explained in terms of different ensemble requirements for paralleVconsecutive reaction paths and also in terms of the so-called ligand effect. As the holes in the d-band of transition metals were assumed to be responsible for adsorption and catalysis by these metals, a filling of these holes by alloying would drastically influence the adsorption capacity of the alloy (Koschel et al., 2000). It is obvious that the changes in selectivity upon alloying cannot simply be accounted for by a decrease in the number of surface atoms exposed to the reactants, and that changes in geometry of the reactive sites and changes in intrinsic activity of the metal surface atoms have to be considered. The electron deficiency character of the metallic centres would increase the strength of their interaction with the electron rich substrates, hindering the subsequent hydrogenation process. As a consequence the metal centres would be covered with the electron-rich substrate, obstructing the adsorption of hydrogen and favouring the isomerization reaction of the 1 -butene with respect to the hydrogenation reaction.On the basis of the above consideration y-alumina supported Cu-Ni catalysts were prepared with the aim of taking advantage of the combination of the properties of the support with those of a bimetallic system. One of the interesting points of this combination i s that Ni and Cu have similar geometric, but very different electronic properties. Both metals have an fcc crystal structure with lattice constants of 3.52 A (nickel) and 3.61 A (copper), respectively. However, their electronic properties are very different. Copper, being a coinage metal, has a completely filled 3d band and therefore no d-states at the Fermi level; in contrast, nickel, being a transition metal, has a partially filled 3d band with a high density of states at the Fermi level. This difference in the electronic structure is Addition of a second metal often improves the selectivity of a supported catalyst for the hydrogenation of 1,3-butadiene. Catalysts containing 15 wt96 Ni and varying amounts of Cu were prepared and characterized by TPR, XRD and XPS. The Cu-Ni interaction affects the reduction behavior of the catalysts. TPR res...

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Parkinson's disease (PD) is pathologically characterized by the accumulation of α-synuclein-positive neuronal cytoplasmic inclusions called Lewy bodies and subsequent nigrostriatal dopaminergic neuronal degeneration [1]. At least 50% loss of the nigral neurons is required to manifest parkinsonian motor symptoms [2]. Even with the relatively high accuracy of current clinical diagnostic criteria of PD [3], early clinical diagnosis is still challenging due to some degree of false-negative and false-positive rates [4]. Therefore, functional