Combined antenna and localized plasmon resonance in Raman scattering from Random arrays of silver-coated, vertically aligned multiwalled carbon nanotubes

The electric field enhancement associated with detailed structure within novel optical antenna nanostructures is modeled using the surface integral equation technique in the context of surface-enhanced Raman scattering (SERS). The antennae comprise random arrays of vertically aligned, multi-walled carbon nanotubes dressed with highly granular Ag. Different types of "hot-spot" underpinning the SERS are identified, but contrasting characteristics are revealed. Those at the outer edges of the Ag grains are antenna driven with field enhancement amplified in antenna antinodes while intergrain hotspots are largely independent of antenna activity. Hot-spots between the tops of antennae leaning towards each other also appear to benefit from antenna amplification.

Transient receptor potential ankyrin 1 channel localized to non-neuronal airway cells promotes non-neurogenic inflammation

The transient receptor potential ankyrin 1 (TRPA1) channel, localized to airway sensory nerves, has been proposed to mediate airway inflammation evoked by allergen and cigarette smoke (CS) in rodents, via a neurogenic mechanism. However the limited clinical evidence for the role of neurogenic inflammation in asthma or chronic obstructive pulmonary disease raises an alternative possibility that airway inflammation is promoted by non-neuronal TRPA1.

The effect of radiation technique and bladder filling on the acute toxicity of pelvic radiotherapy for localized high risk prostate cancer

Purpose: The goal of this project was to see if using IMRT to deliver elective pelvic nodal irradiation (EPNI) for prostate cancer reduced acute treatment toxicity.

Methods: Two hundred and thirty patients were enrolled into prospective trials delivering EPNI with a concomitant hypofractionated IMRT boost to the prostate. During accrual, the method of EPNI delivery changed as new literature emerged. Three methods were used (1) 4FB, (2) IMRT with 2 cm CTV margins around the pelvic vessels as suggested by Shih et al. (2005) [7] (IMRT-Shih), and (3) IMRT with nodal volumes suggested by the RTOG (IMRT-RTOG). Initially patients were treated with an empty bladder, with the remainder treated with bladder full.

Results: Patients in the 4FB group had higher rates of grade 2 acute GI toxicities compared to the IMRT-Shih and IMRT-RTOG groups (31.9% vs 20.8% vs 7.2%, p = 0.0009). Patients in the 4FB group had higher rates of grade 3 urinary frequency compared to the two IMRT groups (8.5% vs 0% vs 0%, p = 0.027). However, multivariate analysis suggested the factor that most influenced toxicity was bladder filling followed by IMRT.

Conclusions: Bladder filling appeared to be the dominant factor which predicted for acute toxicity, followed by the use of IMRT.

Genomic Analysis of Pseudomonas putida Phage tf with Localized Single-Strand DNA Interruptions

The complete sequence of the 46,267 bp genome of the lytic bacteriophage tf specific to Pseudomonas putida PpG1 has been determined. The phage genome has two sets of convergently transcribed genes and 186 bp long direct terminal repeats. The overall genomic architecture of the tf phage is similar to that of the previously described Pseudomonas aeruginosa phages PaP3, LUZ24 and phiMR299-2, and 39 out of the 72 products of predicted tf open reading frames have orthologs in these phages. Accordingly, tf was classified as belonging to the LUZ24-like bacteriophage group. However, taking into account very low homology levels between tf DNA and that of the other phages, tf should be considered as an evolutionary divergent member of the group. Two distinguishing features not reported for other members of the group were found in the tf genome. Firstly, a unique end structure - a blunt right end and a 4-nucleotide 3'-protruding left end - was observed. Secondly, 14 single-chain interruptions (nicks) were found in the top strand of the tf DNA. All nicks were mapped within a consensus sequence 5'-TACT/RTGMC-3'. Two nicks were analyzed in detail and were shown to be present in more than 90% of the phage population. Although localized nicks were previously found only in the DNA of T5-like and phiKMV-like phages, it seems increasingly likely that this enigmatic structural feature is common to various other bacteriophages.

Dressing Plasmons in Particle-in-Cavity Architectures

Placing metallic nanoparticles inside cavities, rather than in dimers, greatly improves their plasmonic response. Such particle-in-cavity (PIC) hybrid architectures are shown to produce extremely strong field enhancement at the particle cavity junctions, arising from the cascaded focusing of large optical cross sections into small gaps. These simply constructed PIC structures produce the strongest field enhancement for coupled nanoparticles, up to 90% stronger than for a dimer. The coupling is found to follow a universal power law with particle surface separation, both for field enhancements and resonant wavelength shifts. Significantly enhanced Raman signals are experimentally observed for molecules adsorbed in such PIC structures, in quantitive agreement with theoretical calculations. PIC architectures may have important implications in many applications, such as reliable single molecule sensing and light harvesting in plasmonic photovoltaic devices.

METHOD OF DETECTING BIOPRODUCTS USING LOCALIZED SURFACE PLASMON RESONANCE SENSOR OF GOLD NANOPARTICLES

(EN)Disclosed is a method of detecting bioproducts using Localized Surface Plasmon Resonance (LSPR) of gold nanoparticles, which can diagnose bioproducts based on changes in the maximum wavelength occurred by an antigen-antibody reaction after immobilization of the gold nanoparticles onto a glass panel. A sensor using such method exhibits high sensitivity, is low in price, and makes quick diagnosis possible, thereby being applicable to various biological fields associated with environmental contaminants, pathogens and the like, as well as diagnosis of diseases. Further, it provides a technology for manufacturing a sensor having higher sensitivity, low price and quick performance, as compared to conventional methods using SPR.

Constitutive model for localized Lüders-like stress-induced martensitic transformation and super-elastic behaviors of laser-welded NiTi wires

The application of the shape memory alloy NiTi in micro-electro-mechanical-systems (MEMSs) is extensive nowadays. In MEMS, complex while precise motion control is always vital. This makes the degradation of the functional properties of NiTi during cycling loading such as the appearance of residual strain become a serious problem to study, in particular for laser micro-welded NiTi in real applications. Although many experimental efforts have been put to study the mechanical properties of laser welded NiTi, surprisingly, up to the best of our understanding, there has not been attempts to quantitatively model the laser-welded NiTi under mechanical cycling in spite of the accurate prediction required in applications and the large number of constitutive models to quantify the thermo-mechanical behavior of shape memory alloys. As the first attempt to fill the gap, we employ a recent constitutive model, which describes the localized SIMT in NiTi under cyclic deformation; with suitable modifications to model the mechanical behavior of the laser welded NiTi under cyclic tension. The simulation of the model on a range of tensile cyclic deformation is consistent with the results of a series of experiments. From this, we conclude that the plastic deformation localized in the welded regions (WZ and HAZs) of the NiTi weldment can explain most of the extra amount of residual strain appearing in welded NiTi compared to the bare one. Meanwhile, contrary to common belief, we find that the ability of the weldment to memorize its transformation history, sometimes known as ‘return point memory’, still remains unchanged basically though the effective working limit of this ability reduces to within 6% deformation.

1-D constitutive model for evolution of stress-induced R-phase and localized Lüders-like stress-induced martensitic transformation of super-elastic NiTi wires

NiTi alloys have been widely used in the applications for micro-electro-mechanical-systems (MEMS), which often involve some precise and complex motion control. However, when using the NiTi alloys in MEMS application, the main problem to be considered is the degradation of functional property during cycling loading. This also stresses the importance of accurate prediction of the functional behavior of NiTi alloys. In the last two decades, a large number of constitutive models have been proposed to achieve the task. A portion of them focused on the deformation behavior of NiTi alloys under cyclic loading, which is a practical and non-negligible situation. Despite of the scale of modeling studies of the field in NiTi alloys, two experimental observations under uniaxial tension loading have not received proper attentions. First, a deviation from linearity well before the stress-induced martensitic transformation (SIMT) has not been modeled. Recent experiments confirmed that it is caused by the formation of stress-induced R phase. Second, the influence of the well-known localized Lüders-like SIMT on the macroscopic behavior of NiTi alloys, in particular the residual strain during cyclic loading, has not been addressed. In response, we develop a 1-D phenomenological constitutive model for NiTi alloys with two novel features: the formation of stress-induced R phase and the explicit modeling of the localized Lüders-like SIMT. The derived constitutive relations are simple and at the same time sufficient to describe the behavior of NiTi alloys. The accumulation of residual strain caused by R phase under different loading schemes is accurately described by the proposed model. Also, the residual strain caused by irreversible SIMT at different maximum loading strain under cyclic tension loading in individual samples can be explained by and fitted into a single equation in the proposed model. These results show that the proposed model successfully captures the behavior of R phase and the essence of localized SIMT.