Coordinated anatomical and functional variability in the human brain during adolescence.

Adolescence represents a time of unparalleled brain development. In particular, developmental changes in morphometric and cytoarchitectural features are accompanied by maturation in the functional connectivity (FC). Here, we examined how three facets of the brain, including myelination, cortical thickness (CT), and resting-state FC, interact in children between the ages of 10 and 15. We investigated the pattern of coordination in these measures by computing correlation matrices for each measure as well as meta-correlations among them both at the regional and network levels. The results revealed consistently higher meta-correlations among myelin, CT, and FC in the sensory-motor cortical areas than in the association cortical areas. We also found that these meta-correlations were stable and little affected by age-related changes in each measure. In addition, regional variations in the meta-correlations were consistent with the previously identified gradient in the FC and therefore reflected the hierarchy of cortical information processing, and this relationship persists in the adult brain. These results demonstrate that heterogeneity in FC among multiple cortical areas are closely coordinated with the development of cortical myelination and thickness during adolescence.

Structural color printing with a dielectric layer coated on a nanotextured metal substrate: simulation and experiment.

The printing of plasmonic structural colors relies on noble metal nanostructures fabricated on Si, glass, or plastic substrates. This paper presents a simple surface structure for producing vivid structural colors directly from common metal substrates. The structure is formed by texturing the surface of stainless steel (STS) via imprinting and coating it with a dielectric layer. Diverse colors are generated simply by varying the thickness of the dielectric layer. The colors arise from surface plasmon resonance and guided-mode resonance of the incident light, which are excited on the textured STS surface and inside the dielectric layer, respectively. A finite-difference time-domain simulation shows that 500 nm is the optimum texture periodicity with regard to the tunability and vividness of the colors. This is experimentally verified by printing many differently colored images on the surface of STS substrates with a texture period of 500 nm. The proposed structure/method does not require a nanofabrication technique such as electron-beam lithography or focused ion beam etching. The results of the study provide a facile route for producing vivid structural colors on metals, which may find various applications, including surface decoration, product identification, anti-counterfeiting, and perfect absorbers.

Fabrication of nano silica dispersed permalloy composite coating.

In aqueous solution, the agglomeration of silica nanopowder is a major problem which causes poor uniformity of electroplated surfaces. Silica surface is susceptible to moisture due to the hydroxyl group on its surface which causes the silica nanopowder to become agglomerated. In this study, silica nanoparticle dispersion in the electroplated layer is reported. From zeta potential analysis, silica nanopowder has a negatively charged surface in an alkaline bath. Silica nanopowder is less agglomerated in an alkaline bath than in an acidic bath due to the surface charge. Additives change the surface morphologies of the electroplated layer as well as the silica nanopowder contents. Comparing an alkaline bath and an acidic bath, the advantage of an additive to the electroplated layer is only observed in an alkaline bath. Types of sonicators and sonication periods are also surveyed for silica nanopowder dispersion. Sonication time can be reduced by a horn-type sonicator, and longer sonication time guaranteed better silica nanopowder dispersion.

Optical properties and spectroscope parameters of Sm(DBM)(3)Phen-doped poly(methyl methacrylate).

Rare-earth complex Sm(DBM)(3)Phen-doped poly(methyl methacrylate) was synthesized and its absorption and luminescence spectra were studied. The relationship between the coordinate environment of rare-earth ions and the Judd-Ofelt intensity parameter Omega(2) was analyzed and the spectroscopic quality factor, Omega(4)/Omega(6), for this material was reported. The oscillator strengths of higher energy levels of Sm(3+) were predicted, which would be useful to assign the closely spaced multiples at higher energies. The radiative properties for fluorescent levels (4)G(4)(7/2), (4)F(3)(3/2) and (4)G(4)(5/2) of Sm(3+) were evaluated. The predicted radiative parameters were compared with the observed luminescence spectrum of Sm(3+) in this system.