Bonelike apatite formation on niobium metal treated in aqueous NaOH

The essential condition for a biomaterial to bond to the living bone is the formation of a biologically active bonelike apatite on its surface. In the present work, it has been demonstrated that chemical treatment can be used to create a calcium phosphate (CaP) surface layer, which might provide the alkali treated Nb metal with bone-bonding capability. Soaking Nb samples in 0.5 M NaOH, at 25 degrees C for 24 h produced a nano-porous approximately 40 nm thick amorphous sodium niobate hydrogel layer on their surface. Immersion in a simulated body fluid (SBF) lead to the deposition of an amorphous calcium phosphate layer on the alkali treated Nb. The formation of calcium phosphate is assumed to be a result of the local pH increase caused by the cathodic reaction of oxygen reduction on the finely porous surface of the alkali-treated metal. The local rise in pH increased the ionic activity product of hydroxyapatite and lead to the precipitation of CaP from SBF that was already supersaturated with respect to the apatite. The formation of a similar CaP layer upon implantation of alkali treated Nb into the human body should promote the bonding of the implant to the surrounding bone. This bone bonding capability could make Nb metal an attractive material for hard tissue replacements.     

Corrosion behavior of PIRAC nitrided Ti-6Al-4V surgical alloy

Hard titanium nitride (TiN) coatings were obtained on the surface of Ti-6Al-4V alloy using an original PIRAC nitriding method, based on annealing the samples under a low pressure of monatomic nitrogen created by selective diffusion of N from the atmosphere. PIRAC nitrided samples exhibited excellent corrosion resistance in Ringer's solution in both potentiodynamic and potentiostatic tests. The anodic current and metal ion release rate of PIRAC nitrided Ti-6Al-4V at the typical corrosion potential values were significantly lower than those of the untreated alloy. This, together with the excellent adhesion and high wear resistance of the TiN coatings, makes PIRAC nitriding an attractive surface treatment for Ti-6Al-4V alloy surgical implants.     

Does familiarity breed contempt or liking? Comment on Reis, Maniaci, Caprariello, Eastwick, and Finkel (2011).

Reis, Maniaci, Caprariello, Eastwick, and Finkel (see record 2011-04644-001) conducted 2 studies that demonstrate that in certain cases, familiarity can lead to liking—in seeming contrast to the results of our earlier article (see record 2006-23056-008). We believe that Reis et al. (a) utilized paradigms far removed from spontaneous, everyday social interactions that were particularly likely to demonstrate a positive link between familiarity and liking and (b) failed to include and incorporate other sources of data—both academic and real-world—showing that familiarity breeds contempt. We call for further research exploring when and why familiarity is likely to lead to contempt or liking, and we suggest several factors that are likely to inform this debate. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Perceptions of Multicultural Training in Predoctoral Internship Programs: A Survey of Interns and Training Directors.

Multicultural training at internship sites is a critical component in the preparation of doctoral-level psychologists, so the quality of this training is of the utmost importance. In the following study, the authors examine multicultural training from the perspective of predoctoral interns and training directors at counseling center sites that offer a major or minor rotation in multicultural therapy. Results suggest that perspectives vary between interns and training directors and that there is a great difference in the type of criteria used by each site as evidence of a major or minor rotation. The need for more standardized criteria to define major and minor rotations and suggestions for the Association of Psychology Postdoctoral and Internship Centers, internship training directors, and prospective interns are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhanced inactivation of E. coli bacteria using immobilized porous TiO2 photoelectrocatalysis

Immobilized TiO₂ nanotube electrodes with high surface areas were grown via electrochemical anodization in aqueous solution containing fluoride ions for photocatalysis applications. The photoelectrochemical properties of the grown immobilized TiO₂ film were studied by potentiodynamic measurements (linear sweep voltammetry), in addition to the calculation of the photocurrent response. The nanotube electrode properties were compared to mesoporous TiO₂ electrodes grown by anodization in sulfuric acid at high potentials (above the microsparking potential) and to 1 g/l P-25 TiO₂ powder. Photocatalyst films were evaluated by high resolution SEM and XRD for surface and crystallographic characterization. Finally, photoelectrocatalytic application of TiO₂ was studied via inactivation of E. coli. The use of the high surface area TiO₂ nanotubes resulted in a high photocurrent and an extremely rapid E. coli inactivation rate of ∼10⁶ CFU/ml bacteria within 10 min. The immobilized nanotube system is proven to be the most potent electrode for water purification.     

Nonlinear resonances in a general class of granular dimers with no pre-compression

In this work we study the existence of nonlinear resonances in a general 1: $N$ one-dimensional granular dimer chains, i.e., granular chains consisting of periodic sets of ‘heavy’ beads followed and preceded by $N$ ‘light’ beads. Each bead is assumed to be spherical and purely elastic and to interact with its neighbors through Hertzian contact law. In a previous work (Jayaprakash et al. in 112(3):1–17, 2012) we proved the existence of countably infinite families of solitary waves in these systems; these are localized pulses that propagate without distortion of their waveforms through these highly inhomogeneous nonlinear media. We attributed these waves to nonlinear anti-resonance that led to complete elimination of radiating waves in the trail of the propagating localized pulse. Anti-resonances were associated with certain symmetries of the velocity waveforms of the beads of the dimer. In this work we report on the opposite phenomenon, that is, of the breakup of waveform symmetries of the bead responses leading to drastic attenuation of propagating pulses due to energy radiation to the far field by means of nonlinear traveling waves. We use the connotation of resonance to describe this dynamical phenomenon resulting in the maximum amplification of the amplitudes of radiated waves that emanate from the propagating pulse. We study numerically and analytically the nonlinear resonance mechanism in this class of strongly nonlinear periodic media, and demonstrate that it can lead to drastic attenuation of shock-induced pulses propagating in the dimers.     

End-point detection of copper super-filling in small features under a potentiostatic mode of operation

Copper filling of small features using a potential-controlled technique in electrolytic bath containing organic additives in a selected potential range is shown to be highly beneficial. End-points filling detection in features with width of less than 150 nm are observed in the current-time profile. This behavior is obtained once potential is applied in a selected potential range, capable of providing efficient copper deposition suppression on flat wafer surface sites. Thus, achieving a controlled feature filling with a clear end-point of copper super-filling with minimum copper overburden is feasible in a potentiostatic operation mode. Copper filling rate depends primarily on the selected potential value and the feature dimension characteristics (aspect ratio). Selective copper filling during potentiostatic deposition is favorable (over galvanostatic deposition) in high aspect ratio patterned wafers. Illustrations of i-t curve profiles during copper super-filling of complex wafer patterns in a potentiostatic mode are presented.     

Solubility and solution thermodynamic properties of quercetin and quercetin dihydrate in subcritical water

Fundamental physicochemical data is required for the design and optimization of food engineering processes, such as extraction. Flavonoids are present in natural products such as grapes and have numerous health benefits particularly with respect to their reported antioxidant properties. Such flavonoid compounds can be extracted from these natural products using a variety of solvents, among them water. In this study, the aqueous solubilities of 3,3′,4′,5,7-pentahydroxyflavone (quercetin) and its dihydrate were measured at temperatures between 25 and 140 °C using a continuous flow type apparatus. The flow rate of subcritical water was studied at 0.1, 0.2 and 0.5 mL/min to study its effect on quercetin solubility and thermal degradation at temperatures greater than 100 °C. The aqueous solubility of anhydrous quercetin varied from 0.00215 g/L at 25 °C to 0.665 g/L at 140 °C and that of quercetin dihydrate varied from 0.00263 g/L at 25 °C to 1.49 g/L at 140 °C. The aqueous solubility of quercetin dihydrate was similar to that of anhydrous quercetin until 80 °C. At temperatures above or equal to 100 °C, the aqueous solubility of quercetin dihydrate was 1.5–2.5 times higher than that of anhydrous quercetin. The aqueous solubility of quercetin anhydrate and dihydrate at different temperatures was correlated using a modified Apelblat equation. The thermodynamic properties of the solution of quercetin and its dihydrate in water were than estimated from their solubility values. A flow rate effect on the aqueous solubility of quercetin and its dihydrate was not observed until above 100 °C where higher solvent (water) flow rates (>0.1 mL/min) were required to maintain a constant solubility in the saturation cell and with minimal thermal degradation of the solute (quercetin dihydrate). The study of its particle morphology under SEM indicated an aggregation of the crystals of quercetin dihydrate at subcritical water temperatures and at lower flow rates (<0.5 mL/min), thereby inhibiting stable solubility measurements and solvent flow through the saturation cell.