Serotonin transporter gene associations with psychopathic traits in youth vary as a function of socioeconomic resources.

Although prior research has examined the genetic correlates of antisocial behavior, molecular genetics influences on psychopathic traits remain largely unknown. Consequently, we investigated the influence of polymorphic variation at the serotonin transporter protein gene (SLC6A4) and socioeconomic resources (SES) on psychopathic traits in youth across two distinct samples in two separate studies. In Study 1, a main effect of serotonin transporter (5-HTTLPR) genotype was associated with the impulsivity dimension of psychopathy. That is, individuals homozygous for the short allele evidenced more impulsivity than did those homozygous for the long allele. In contrast, a gene–environment interaction was associated with the callous-unemotional and narcissistic features of psychopathy. Callous-unemotional and narcissistic traits increased as SES decreased only among youths with the homozygous-long (l/l) genotype, a novel finding replicated and extended in Study 2. These studies provide preliminary results that the l/l genotype confers risk for the emotional deficits and predatory interpersonal traits associated with psychopathy among youths raised in disadvantaged environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factors determining the stability, resolution, and precision of a conventional Raman spectrometer

We verified the performance of a conventional Raman spectrometer, which is composed of a 30 cm single polychromator, a Si based charge-coupled device (CCD) camera, and a holographic supernotch filter. For that purpose, the time change of the peak positions of Raman spectra of naphthalene and fluorescence spectra of ruby (Cr-doped Al(2)O(3)) were monitored continually. A time-dependent deviation composed of two components was observed: a monotonous drift up to 0.4 cm(-1) and a periodic oscillation with a range of 0.15 cm(-1). The former component was stabilized at approximately 2000 s after the CCD detector was cooled, indicating that incomplete refrigeration of the CCD detector induced the drift. The latter component synchronized with the periodic oscillation of the room temperature, indicating that thermal expansion or contraction of the whole apparatus induced this oscillation. The implemental deviation is reduced when measurements are conducted using a sufficiently cooled CCD detector at a constant room temperature. Moreover, the effect of the room temperature oscillation is lowered in a spectrum acquired over a duration that is longer than one cycle of this oscillation. Applying the least squares fitting method to carefully measured spectra enhanced the precision of the determination of the peak position to 0.05 cm(-1) using the spectrometer with pixel resolution of 1.5 cm(-1).     

Plasmonic nanoparticle heterodimers in a semiembedded geometry fabricated by stepwise upright assembly

We report the experimental realization of plasmonic heterodimers, pairs of directly adjacent, interacting metallic nanoparticles. A novel fabrication and positioning approach is utilized for the stepwise assembly of upright nanoparticle pairs, where the first nanoparticle is almost entirely embedded in an elastomeric dielectric medium prior to attachment of the second nanoparticle. The plasmon energies of the embedded nanoparticles are red-shifted, and the strongly anisotropic dielectric environment of the semiembedded nanoparticle pairs effectively transforms the structures into plasmonic heterodimers. The asymmetric hybridization of the plasmon modes of differing energies on the constituent nanoparticles of the heterodimer is clearly observed.     

Nanorice: a hybrid plasmonic nanostructure

We have designed and fabricated a new hybrid nanoparticle that combines the intense local fields of nanorods with the highly tunable plasmon resonances of nanoshells. This dielectric core-metallic shell prolate spheroid nanoparticle bears a remarkable resemblance to a grain of rice, inspiring the name "nanorice". This geometry possesses far greater structural tunability than either a nanorod or a nanoshell, along with much larger local field intensity enhancements and far greater sensitivity as a surface plasmon resonance (SPR) nanosensor than any dielectric-metal nanostructures reported previously. Invoking the plasmon hybridization picture allows us to understand the plasmon resonances of this geometry, as arising from a hybridization of the primitive plasmons of a solid spheroid and an ellipsoidal cavity inside a continuous metal.     

A plasmonic fano switch

Plasmonic clusters can support Fano resonances, where the line shape characteristics are controlled by cluster geometry. Here we show that clusters with a hemicircular central disk surrounded by a circular ring of closely spaced, coupled nanodisks yield Fano-like and non-Fano-like spectra for orthogonal incident polarization orientations. When this structure is incorporated into an uniquely broadband, liquid crystal device geometry, the entire Fano resonance spectrum can be switched on and off in a voltage-dependent manner. A reversible transition between the Fano-like and non-Fano-like spectra is induced by relatively low (～6 V) applied voltages, resulting in a complete on/off switching of the transparency window.     

Graphene-antenna sandwich photodetector

Nanoscale antennas sandwiched between two graphene monolayers yield a photodetector that efficiently converts visible and near-infrared photons into electrons with an 800% enhancement of the photocurrent relative to the antennaless graphene device. The antenna contributes to the photocurrent in two ways: by the transfer of hot electrons generated in the antenna structure upon plasmon decay, as well as by direct plasmon-enhanced excitation of intrinsic graphene electrons due to the antenna near field. This results in a graphene-based photodetector achieving up to 20% internal quantum efficiency in the visible and near-infrared regions of the spectrum. This device can serve as a model for merging the light-harvesting characteristics of optical frequency antennas with the highly attractive transport properties of graphene in new optoelectronic devices.     

Monodisperse, Submicrometer Droplets via Condensation of Microfluidic-Generated Gas Bubbles

Microfluidics (MFs) can produce monodisperse droplets with precise size control. However, the synthesis of monodisperse droplets much smaller than the minimum feature size of the microfluidic device (MFD) remains challenging, thus limiting the production of submicrometer droplets. To overcome the minimum micrometer-scale droplet sizes that can be generated using typical MFDs, the droplet material is heated above its boiling point (bp), and then MFs is used to produce monodisperse micrometer-scale bubbles (MBs) that are easily formed in the size regime where standard MFDs have excellent size control. After MBs are formed, they are cooled, condensing into dramatically smaller droplets that are beyond the size limit achievable using the original MFD, with a size decrease corresponding to the density difference between the gas and liquid phases of the droplet material. Herein, it is shown experimentally that monodisperse, submicrometer droplets of predictable sizes can be condensed from a monodisperse population of MBs as generated by MFs. Using perfluoropentane (PFP) as a representative solvent due to its low bp (29.2 °C), it is demonstrated that monodisperse PFP MBs can be produced at MFD temperatures >3.6 °C above the bp of PFP over a wide range of sizes (i.e., diameters from 2 to 200 μm). Independent of initial size, the generated MBs shrink rapidly in size from about 3 to 0 °C above the bp of PFP, corresponding to a phase change from gas to liquid, after which they shrink more slowly to form fully condensed droplets with diameters 5.0 ± 0.1 times smaller than the initial size of the MBs, even in the submicrometer size regime. This new method is versatile and flexible, and may be applied to any type of low-bp solvent for the manufacture of different submicrometer droplets for which precisely controlled dimensions are required.     

13C CP/MAS NMR study of accommodation of various organic molecules in (±)-[Co(en)3]Cl3 ionic crystal and their local structure

Accommodation of various organic molecules into a one-dimensional nanochannel of tris(ethylenediamine) cobalt(III) chloride, [Co(en)₃]Cl₃, anhydrated racemic crystal was examined using weight increment measurements, thermogravimetric–differential thermal analysis (TG–DTA), powder X-ray diffraction (PXRD) and ¹³C cross-polarization/magic angle sample spinning (CP/MAS) NMR techniques. Results showed that the (±)-[Co(en)₃]Cl₃ ionic crystal accommodates n-alkanes, n-alkylalcohols, n-alkylamines, and acetonitrile in the 1D nanochannel without decomposition of the crystal lattice. The guest molecules are in all-trans conformation in the nanochannel. Furthermore, the activation energies of uni-axial molecular reorientation of n-alkanes and n-alkylalcohols in the nanochannel were determined using temperature dependence of the ¹H spin–lattice relaxation time in the rotating frame (T_1ρ). Results demonstrated that the activation energy per CH₂ unit (6.5 kJ mol^?1) in n-alkylalcohols was twice that in n-alkanes (3.3 kJ mol^?1), implying the possibility of dimer formation of n-alkylalcohols in the nanochannel by hydrogen bonding through OH group. These findings strongly suggest that the (±)-[Co(en)₃]Cl₃ ionic crystal has adsorption ability to various organic molecules. It will open new avenues to explore new types of zeolites that include ionic crystals.