Highly Correlated Size and Composition of Pt/Au Alloy Nanoparticles via Magnetron Sputtering onto Liquid.

Pt/Au alloy nanoparticles (NPs) in a wide composition range have been synthesized by room-temperature simultaneous sputter deposition from two independent magnetron sources onto liquid PEG (MW = 600). The prepared NPs were alloyed with the face-centered cubic (fcc) structure. In addition, the particle sizes, composition, and shape are strongly correlated but can be tailored by an appropriate variation of the sputtering parameters. No individual particle but large agglomerates with partial alloy structure formed at Pt content of less than 16 atom %. Highly dispersed NPs with no agglomeration were observed in PEG when the quantity of Pt is more than 26 atom %. On the other hand, a small amount of Pt could terminate the agglomeration of Au when sputtering on the grids for transmission electron microscope observation. Our experiment and computer simulation carried out by two different methods indicate that the composition-dependent particle size of Pt/Au can be explained by the atomic concentration, formation energy of the cluster, and interaction between different metal atoms and the PEG molecule.

Effect of moderate exercise intensities on the cortical activity in young adults.

[Purpose] To examine the influence of different exercise intensities on cortical activity. [Participants and Methods] Twenty-six healthy adults aged 20-30 years performed exercise at three intensities on a bicycle ergometer as follows: (a) 15-minute exercise at 40% peak oxygen uptake, (b) same as (a) but at 60% peak oxygen uptake, and (c) 15 minutes of rest. The cognitive function of the participants was measured before and after exercise by the Paced Auditory Serial Addition Test (PASAT) under these three conditions. The cerebral blood flow in the left prefrontal and temporal cortices was measured using near-infrared spectroscopy during the PASAT. [Results] The PASAT score was significantly higher after exercise under condition (b) than before exercise (41.4 ± 9.1 vs. 47.7 ± 8.3). The cerebral blood flow in the prefrontal cortex under condition (b) was significantly increased compared to that under condition (c), as determined by the Tukey method (0.019 ± 0.030 vs. -0.008 ± 0.044). Significant differences were not observed in the cerebral blood flow in the temporal cortex under these three conditions. [Conclusion] Cortical activation of the frontal lobe increased after high-intensity aerobic exercise with no change in the cortical activity of the temporal lobe.

Disease state changes and safety of long-term donepezil hydrochloride administration in patients with Alzheimer's disease: Japan-Great Outcome of Long-term trial with Donepezil (J-GOLD).

BACKGROUND: A long-term, large-scale study of donepezil hydrochloride in patients with Alzheimer's disease (AD) was conducted. Previously, two interim reports were published during this study. We have now completed the study and herein present our analysis of the final results. METHODS: The subjects of this study included AD patients who received the drug for the first time (newly treated patients), as well as AD patients who were already receiving the drug at the start of the study (continuously treated patients). The observation period was 48 months. Changes in cognitive function and severity of dementia associated with the drug administration and its safety were assessed. RESULTS: Cognitive function decreased significantly after 24 months in newly treated patients and after 6 months in continuously treated patients, compared with baseline. The percentages of patients whose dementia severity improved or remained the same compared with baseline were 59.27% at 48 months in the newly treated patients and 57.09% at 48 months in the continuously treated patients. There were no major safety problems with the drug. CONCLUSIONS: We conducted a large-scale study of AD patients in Japan. Here, we present our analysis of the final results and describe current clinical practice with the drug, changes in cognitive function and dementia severity associated with long-term administration of the drug, and the drug's safety.

Enhanced hydrogen desorption properties of LiAlH4 by doping lithium metatitanate.

High efficiency catalysts are needed to improve the kinetics of complex hydrides for practical applications. In this study, lithium metatitanate (Li2TiO3) is introduced in lithium alanate (LiAlH4), and the catalytic effect for notable complex/metal hydrides, such as LiAlH4, is investigated. Experiment results indicate that Li2TiO3 improves the kinetics of LiAlH4. In particular, Li2TiO3 dramatically improves the onset temperature of LiAlH4, which decreases to 75 °C and is within the temperature range for use in proton exchange membrane fuel cells. Transmission electron microscopy (TEM) observations help understand the catalytic effect of Li2TiO3 in the nanoscale. First principles calculations also show the improvement of H- and Li+ mobility by doping Li2TiO3, where calculations indicate that the physical origin of the catalytic effect is due to two factors: charge transfer and minor surface relaxation. Thus, experimental and theoretical evidence reveals the catalytic mechanism of Li2TiO3 in LiAlH4.

Hydrogen Absorption of Palladium Thin Films Observed by in Situ Transmission Electron Microscopy with an Environmental Cell.

A window type of the environmental cell system for a high-voltage electron microscope was developed and applied to in situ observation of a palladium (Pd) thin film. For in situ hydrogenation of Pd thin films, the distances of the lattice fringes were 0.20 and 0.23 nm, which correspond to the lattice d spacings of ß-phase (200) and (111) planes. Expansion of the Pd lattice happened as a result of phase transformation from the α phase to the ß phase. In particular, the lattice fringes were clearly distinguished, and the dislocation behavior during Pd hydrogenation was easily recognized according to the corresponding inverse fast fourier transform images. Furthermore, significant growth in the number of dislocations was observed at the grain boundary during increasing hydrogen pressure in the cell.

The effect of point defects on diffusion pathway within α-Fe.

The diffusion mechanism of point defects within α-Fe with a single vacancy is investigated using the density functional theory. Calculation reveals that H has a slight effect towards Fe diffusion to a vacancy. He has a strong binding with a vacancy; therefore, Fe diffusion is unlikely to happen. The diffusion of C and N from a vacancy has a high barrier. However, Fe diffusion to a vacancy decreases if the C and N diffuse from a vacancy. Thus, the effect of interstitial atoms within α-Fe with a single vacancy towards diffusion and a possible diffusion pathway is discussed.

Interaction of electrons with light metal hydrides in the transmission electron microscope.

Transmission electron microscope (TEM) observation of light metal hydrides is complicated by the instability of these materials under electron irradiation. In this study, the electron kinetic energy dependences of the interactions of incident electrons with lithium, sodium and magnesium hydrides, as well as the constituting element effect on the interactions, were theoretically discussed, and electron irradiation damage to these hydrides was examined using in situ TEM. The results indicate that high incident electron kinetic energy helps alleviate the irradiation damage resulting from inelastic or elastic scattering of the incident electrons in the TEM. Therefore, observations and characterizations of these materials would benefit from increased, instead decreased, TEM operating voltage.

Hydrogen-induced change in core structures of {110}[111] edge and {110}[111] screw dislocations in iron.

Employing the empirical embedded-atom method potentials, the evolution of edge and screw dislocation core structure is calculated at different hydrogen concentrations. With hydrogen, the core energy and Peierls potential are reduced for all dislocations. A broaden-core and a quasi-split core structure are observed for edge and screw dislocation respectively. The screw dislocation and hydrogen interaction in body-centred cubic iron is found to be not mainly due to the change of elastic modulus, but the variation of dislocation core structure.

Plastic bag method for active sample loading into transmission electron microscope.

A plastic bag method was developed to observe air-sensitive samples on microstructure and phase distribution without exposure to air during the holder transfer process into the transmission electron microscope (TEM). As an example, a type of lithium aluminum hydride (Li(3)AlH(6)) was observed in the TEM to demonstrate the effectiveness of this method. Results show that the plastic bag method is a simple and practical TEM transfer method utilized to reduce air contact for a series of air-sensitive materials.