Objectives: Excessive adipose tissue, especially in the abdominal area, is associated with increased risk of dementia in older adults. However, the mechanisms underlying this relationship are poorly understood. As increased adiposity is also associated with lower circulating levels of brain-derived neurotrophic factor (BDNF), a key molecule modulating brain plasticity and neuronal regeneration, we hypothesized that the changes in cognition that occur as a result of excessive abdominal adiposity would be driven by lower levels of circulating BDNF. Methods: Fasting blood samples were obtained from 60 participants aged 40–60 years (mean±SD=52.3±5.6) and BDNF levels were assessed with an enzyme linked immunosorbent assay. Abdominal adiposity was measured using a ratio of waist circumference to hip circumference (WHR). Participants also completed a neuropsychological assessment battery to assess executive function. Statistical mediation was assessed using traditional causal steps and nonparametric bootstrapping. Results: Higher WHR was significantly associated with poorer performance on the Controlled Oral Word Association (COWA) letter fluency test (β=−0.489; p=.003) and lower levels of circulating BDNF (β=−0.345; p=.006). Linear regression and bootstrapping methods indicated that BDNF fully mediated the relationship between WHR and performance on the COWA (β=0.60; 95% confidence interval [−3.79, −0.26]). Conclusions: The relationship between higher WHR and verbal fluency was fully statistically mediated by circulating BDNF levels. The BDNF pathway is thus a useful probable mechanism through which executive function decline occurs in individuals with high abdominal adiposity. BDNF enhancing interventions (physical exercise and dietary restriction) could thus be used to improve executive function in these individuals. (JINS, 2016, 22, 1–8)

In order to integrate porous dielectric materials into the next generation of Cu/low-k interconnect, the porous material has to be sealed against metal barrier precursor. We have reported pore sealants which forms ultra-thin (< 3 nm-thick) layer on top of the surface of porous low-k film while the pore sealant does not diffuse into pores. In this study, it was investigated how pore seal layer is formed on the surface of porous material and how pore mouths are sealed by pore seal layer. It was found that 1) thickness of the pore seal layer is well-controlled in the range < 5 nm, by varying spin rate and concentration of solid, 2) minimal thicknesses of the pore seal layer needed to achieve an efficient sealing for porous low-k films whose pore radius is 1.5 nm was 2.6 nm. 3) Larger pores, whose pore radius is 4.2 nm, were sealed completely with an expansion of our technology.

Lattice volume expansion or amorphization renders EuTiO3 ferromagnetic, although the stable phase of crystalline EuTiO3 is an antiferromagnet. The lattice volume expansion is induced into the crystalline EuTiO3 thin film by utilizing the lattice mismatch between the thin film and a substrate. The magnetization at low temperatures monotonically increases with an increase in lattice volume for the crystalline EuTiO3 thin film, coincident with the results of calculations based on the hybrid Hartree–Fock density functional approach. The ferromagnetic interaction between Eu2+ ions is enhanced by the amorphization as well; the amorphous EuTiO3 thin film becomes a ferromagnet, and the Curie temperature is higher for amorphous Eu2TiO4 than for its crystalline counterpart. The phenomenon, that is, the volume expansion- and amophization-induced ferromagnetism, is explained in terms of the competition between ferromagnetic and antiferromagnetic interactions among Eu2+ ions.

Pore sealing has become a critical issue for the implementation of porous low-k dielectrics and for realizing acceptable reliability performance of the interconnect. This study focuses on fabrication of ultra-thin, conformal and plasma resistant pore seal layer and on understanding parameters playing a role in sealing the surfaces of porous low-k films. It was found that 2.5 nm-thick pore seal layer shows a perfect toluene seal property for the porous low-k film whose pore radius is 1.48 nm. The pore seal layer still show a good toluene seal property after irradiation of He plasma at 250°C for 10 sec. The increments of dielectric constant by applying the pore seal layer and by the He plasma irradiation for 10 sec are 0.04 and 0.03, respectively. Interestingly, all of toluene seal property, refractive index of the bottom part of the film and dielectric constant started to deteriorate after irradiation of He plasma for 20 sec. It was suggested that when toluene seal property degrades, plasma would start diffusing into pores and both refractive index of the bottom part of the film and k value start to increase.

It was found for the first time that the control of the size of pore sealant is important to prevent diffusions of pore sealant into pores of porous low-k films and to achieve a good toluene seal property. Two pore sealants (PS-A, B) were prepared and the seal property and porous structure were studied using toluene based ellipsometric porosimetry (EP) measurements. It was revealed that small pore sealant (PS-B) diffuses into pores of porous low-k (PLK) films and did not show any seal property, while large pore sealant (PS-A) does not diffuse into pores of porous low-k films and shows a good toluene seal property. Ellipsometry shows that PS-A forms conformal layer only on the vicinity of surface of porous low-k films, but porous structure of porous low-k films at the bottom part is kept, according the fact that the refractive index did not increase.

Furthermore, we developed a new pore seal material (PS-C) to form ultra-thin conformal layer by a single pass, which shows a good toluene seal property. The dielectric constant increased from 2.10 to 2.25 by covering with PS-C. The obtained layer also shows the effect as the protect layer of porous low-k films from plasma damages.

Bulk EuTiO3 is known as a compound in which spin and soft phonon mode is strongly coupled. Recent theoretical study suggests that application of stress or formation of strain leads to a drastic change in magnetic and dielectric properties of EuTiO3 and that so-called multiferroic properties emerge under such a situation. In the present study, effect of strain induced by a substrate, on which EuTiO3 thin film is deposited, on the magnetic properties of the film has been experimentally examined. By using a pulsed laser deposition method, EuTiO3 thin film has been deposited on different kinds of substrate, i.e., LaAlO3, SrTiO3, and DyScO3; the lattice parameter of these compounds is smaller than, just the same as, and larger than that of EuTiO3, respectively. X-ray diffraction analysis confirms that the strain induced in the plane of as-deposited EuTiO3 thin films on different substrates is coincident with the lattice parameter of the substrate compounds. Also, all the as-deposited EuTiO3 thin films manifest elongation of lattice in a direction perpendicular to the film surface. Temperature dependence of magnetization indicates that all the thin films exhibit ferromagnetic behavior at low temperatures. The magnetization at 2 K under a magnetic field of 100 Oe is the highest for EuTiO3 on DyScO3 and the lowest for EuTiO3 on LaAlO3. The experimental result is coincident with the first-principles calculations which predict that ferromagnetic spin configuration becomes more stable as the lattice volume of EuTiO3is increased.

We focused on detailed evaluations of properties of the ultra-thin pore-seal layer (< 3 nm-thick), such as Cu diffusion barrier property and thermal stability. Cu diffusion into dense thermal silica and porous silica low-k which are covered with the pore seal layer was evaluated using metal-insulator-semiconductor (MIS) capacitors under bias thermal stress (BTS). Triangular voltage sweep (TVS) measurement shows that the ultra-thin layer on dense thermal silica suppresses the drift of Cu ions. The Time-Dependent Dielectric Breakdown (TDDB) lifetime of porous silica low-k covered with the ultra-thin pore seal layer results in a drastic increase of the capacitor lifetime with respect to the no-pore-seal control system (stable at 125 °C at least for 10000 s). Thermal decomposition of bulk material of the pore sealant was measured by thermal gravity (TG) test in nitrogen. Bulk material did not decompose through around 350 °C. The amount of ultra-thin pore seal layer fabricated on silicon wafer after thermal cycle stress in vacuum was measured by x-ray photoelectron spectroscopy (XPS). Amount of pore sealant did not decrease even after 2 cycles of 20 min, at 250 °C. Those results show that the ultra-thin layer, which we propose here, has a potential as a pore seal layer for porous low-k films.

We succeeded in fabricating ultra-thin (<3 nm-thick) layer on top of the surface of porous low-k. The roughness of the surface of porous low-k remains homogeneous even after covering by the thin layer. Furthermore, we found that such ultra-thin layer suppresses the diffusion of metal into porous low-k film. Concerning adhesion property, the abrasion between the thin layer and copper was not detected after annealing at 350 deg C in forming gas. TVS measurement suggested that pH control of solution is the key to reduce damages of porous low-k and mobile ions. We believe that such ultra-thin layer, which we propose here, has a potential as a pore seal layer for porous low-k films.

An innovative exercise machine, which mimics the movement of horseback riding, has been made available in the market. As an initial step in characterizing this device, we determined the cardiovascular and metabolic responses to exercise. Twenty apparently healthy subjects rode the device (Equus) on day 1. The upper body exercises were added on day 2, to see whether cardiac and metabolic demands were further elevated (Equus+aerobics). After 10 min of continuous exercise, oxygen consumption increased significantly. In the Equus+aerobics condition, increase in oxygen consumption was significant as early as 4 min into the graded exercise test. Overall oxygen consumption was greater in the Equus+aerobics condition than in the Equus condition (P < 0.05). Oxygen consumption returned to baseline levels within 1 h after the Equus (190 ± 58–188 ± 50 ml min− 1) and Equus+aerobics (198 ± 54–194 ± 43 ml min− 1) conditions. Heart rates increased gradually during the graded exercise tests in both conditions (64 ± 11–78 ± 15 and 65 ± 11–83 ± 12 bpm in the Equus and Equus+aerobics conditions, respectively). Both systolic and diastolic blood pressure (BP) increased significantly 6 min into the graded exercise tests and remained elevated throughout exercise in both the conditions. There were no significant differences in BP responses between the two conditions. These results indicate that the cardiac and metabolic stresses achieved with this exercise device are small.

A novel process of TMCTS vapor annealing combined with a plasma treatment has been developed for improving the mechanical strength of porous silica films having ultralow dielectric constant. When porous silica films annealed under 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) vapor were treated with argon plasma and then re-treated with TMCTS vapor, the mechanical strength (i.e., elastic modulus, hardness) of the films increased significantly. Results of Fourier transform infrared spectroscopy (FT-IR) suggested an accelerative effect resulted from the plasma treatment on the conversion of Si-CH3 and Si-H groups to Si-OH groups. The latter group appears to react faster with TMCTS from the second annealing to form cross-linked polymer network on the porous silica wall surfaces. The resulting cross-linked network is thought to keep the low permittivity and enhance the mechanical strength of the low-k films.

A novel organosiloxane-vapor-annealing method has been developed for improving the mechanical strength of porous silica films with a low dielectric constant. Treatment of a porous silica film with 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) under atmospheric nitrogen above 350 °C significantly enhanced the mechanical strength (i.e., elastic modulus and hardness) of the film. Results of Fourier transform infrared spectroscopy (FT-IR) and thermal desorption spectroscopy (TDS) suggested the formation of cross-linked poly(TMCTS) network on the porous silica internal wall surfaces by the TMCTS treatment. Such TMCTS cross-linked network is thought to enhance the mechanical strength of the low-k film.

CO2 laser irradiation onto growing a-Si:H surface caused a decrease of the optical bandgap down to 1.63 eV and a significant increase of the photosensivity. Primary effect of the laser irradiation was a conventional substrate heating, while the optical bandgap narrowing could not be explained by heating effect alone.