Electro-optical modulation for a boron nitride nanotube probed by first-principles calculations

[[abstract]]The electro-optical modulation effect of a (10,0) boron nitride nanotube is investigated by first-principles, density functional theory calculations. The optical properties of boron nitride nanotubes can be tuned through perturbation by a transverse electric field. Large optical anisotropy in variations of the absorption spectra and refractive indices in response to external electric field is found. In addition, a method called the band-resolved absorption density analysis technique is developed to investigate the detailed optical absorption transition processes. The result is consistent with the recent experimental observation [M. Ishigami et al., Phys. Rev. Lett.94, 56804 (2005)] and suggests that the boron nitride nanotubes can be a promising material for electro-optical modulation device applications.[[notice]]補正完畢[[booktype]]紙本[[booktype]]電子

Dynamics of Order Parameter in Photoexcited Peierls Chain

The photoexcited dynamics of order parameter in Peierls chain is investigated by using a microscopic quantum theory in the limit where the hot electrons may establish themselves into a quasi-equilibrium state described by an effective temperature. The optical phonon mode responsible for the Peierls instability is coupled to the electron subsystem, and its dynamic equation is derived in terms of the density matrix technique. Recovery dynamics of the order parameter is obtained, which reveals a number of interesting features including the change of oscillation frequency and amplitude at phase transition temperature and the photo-induced switching of order parameter.Comment: 5 pages, 3 figure

Pre-clinical development of chimeric virus-like particles based HPV: HIV vaccines by using mammalian cell expression system: limitations and challenges

[eng] HPV and HIV-1 are important public health issues in some developing and industrialized countries, but an effective chimeric HPV:HIV preventive vaccine is still unachievable. We aimed to establish an alternative mammalian (293F) cell expression system combining with chromatographic purification methods to reach an appreciable expression level, purity and recovery rate of chimeric HPV:HIV VLPs. In this study, the chimeric HPV:HIV (L1:P18I10 and L1:T20) immunogens were designed and produced by using 293F expression system. The HPV:HIV VLPs were subsequently purified by a 3-step chromatographic method, including cation (CEC), size exclusion (SEC) and heparin affinity (H-AC) chromatography. Then, the in vitro stability, in vitro self assembly and morphology of purified HPV:HIV VLPs were confirmed by non-reducing SDS-PAGE, molecular mass assay, transmission electron microscopy (TEM) respectively. The sequential and conformational P18I10 and T20 peptides presented on chimeric HPV:HIV VLPs were further characterized by HIV-1 anti-V3 and anti-2F5 monoclonal antibodies in vitro by using Western blot and indirect ELISA. Finally, the immunogenicity of HPV:HIV VLPs were assessed in BALB/c mice model. Because the development and manufacturing of an immunogenic HPV:HIV vaccine is still unachievable, this study provided a baseline strategy that may be worthy to support the global efforts to develop novel chimeric VLP-based vaccines for controlling HPV and HIV-1 infection

Possible pi-phase shift at interface of two pnictides with antiphase s-wave pairing

We examine the nature of Josephson junction between two identical Fe-pnictides with anti-phase s-wave pairing. pi-phase shift is found if the junction barrier is thick and the two Fe-pnictides are oriented in certain directions relative to the interface. Our theory provides a possible explanation for the observed half integer flux quantum transitions in a niobium/polycrystal NdFeAsO loop, and attributes the pi-phase shift to intergrain junctions of Fe-pnictides.Comment: 4 pages, 2 figure

Effectiveness of postharvest sanitation treatments on microbial load of blueberries

The purpose of this study was to determine the quality and microbial load of blueberries at different maturity stages, to develop the effective microbial recovery method and to compare sanitation postharvest treatments on microbial counts of blueberries. The soluble solids and the sugar to acid ratio increased, while pH and TA decreased with maturity. Ripe berries had lower yeast and mold counts (YMC) at other maturity stages, but there were no differences on aerobic plate counts (APC). The medium pH was lower for stomaching and blending than hand massaged samples. This leads to higher recovery of microorganisms by massaging. Sodium hypochlorite at 400 ppm was effective in reducing APC but not YMC. Acidified sodium chloride was very effective, lowering APC and YMC below detectable level. All sanitation treatment did not influence sensory attributes of blueberries

Simulation of a morphological image processor using VHDL - Part I: Mathematical Components

Very high speed integrated circuit Hardware Description Language (VHDL) is utilized in this project to model a Morphological Image Processor (MIP) Array. Both behavioral and structural models have been established at the system level, and the simulation results from both models are consistent with each other. The successful implementation of the models accomplishes our original goal to document the MIP with VHDL. It is observed from the project that VHDL is a powerful language. It is flexible since it can be used to model any level of a system independent of the technology