High Sensitivity Sensors Made of Perforated Waveguides

Sensors based on surface plasmons or waveguide modes are at the focus of interest for applications in biological or environmental chemistry. Waveguide-mode spectra of 1 μm-thick pure and perforated silica films comprising isolated nanometric holes with great aspect ratio were measured before and after adhesion of streptavidin at concentrations of 500 nM. The shift of the angular position for guided modes was nine times higher in perforated films than in bulk films. Capturing of streptavidin in the nanoholes is at the origin of that largely enhanced shift in the angular position as the amplitude of the guided mode in the waveguide perfectly overlaps with the perturbation caused by the molecules. Hence, the device allows for strongly confined modes and their strong perturbation to enable ultra-sensitive sensor applications

Balloon-expandable Metallic Stents for Airway Diseases

Stent placement is an essential treatment for airway diseases. Although self-expandable metallic stents and silicone stents are commonly applied for the treatment of airway diseases, these stents are unsuitable for the treatment of small airway diseases encountered in pediatric patients and lung transplant recipients with airway complications. Currently, only vascular balloon-expandable metallic stents are available for the treatment of small airway diseases; however, little research has been conducted on the use of these stents in this field. We have launched a prospective feasibility study to clarify the safety and efficacy of balloon-expandable metallic stents for the treatment of airway diseases

Optical pumping NMR in the compensated semiconductor InP:Fe

The optical pumping NMR effect in the compensated semiconductor InP:Fe has been investigated in terms of the dependences of photon energy (E_p), helicity (sigma+-), and exposure time (tau_L) of infrared lights. The {31}P and {115}In signal enhancements show large sigma+- asymmetries and anomalous oscillations as a function of E_p. We find that (i) the oscillation period as a function of E_p is similar for {31}P and {115}In and almost field independent in spite of significant reduction of the enhancement in higher fields. (ii) A characteristic time for buildup of the {31}P polarization under the light exposure shows strong E_p-dependence, but is almost independent of sigma+-. (iii) The buildup times for {31}P and {115}In are of the same order (10^3 s), although the spin-lattice relaxation times (T_1) are different by more than three orders of magnitude between them. The results are discussed in terms of (1) discrete energy spectra due to donor-acceptor pairs (DAPs) in compensated semiconductors, and (2) interplay between {31}P and dipolar ordered indium nuclei, which are optically induced.Comment: 8 pages, 6 figures, submitted to Physical Review

Comparison of Dielectric Properties between Epoxy Composites with Nanosized Clay Fillers Modified by Primary Amine and Tertiary Amine (Final draft (Post-print) version)

Epoxy-based nanocomposites (NCs) were prepared using clay modified by either primary amine or tertiary amine, and the effect of the difference in modifier on the thermal and dielectric properties of the NCs were discussed. The NC with clay fillers modified by the primary amine, 1C, shows a glass transition end temperature (Teg) at a temperature 20°C lower than the neat epoxy (N). This indicates that the resin of 1C is less crosslinked than that of N. On the other hand, the sample 3C, in which the clay was modified by the tertiary amine, shows a DSC spectrum close to that of N. Namely, 3C has a high crosslinking density similar to N. While the three samples show a relaxation peak in their dielectric loss spectra, the peak appears at high frequencies in 1C compared to N and 3C. Moreover, ionic conduction current flows more at high temperatures in 1C than in N or 3C. These facts are ascribable to the difference in their crosslinking densities

Dielectric properties of epoxy/clay nanocomposites : effects of curing agent and clay dispersion method (Final draft (Post-print) version)

Effects of the differences in the curing agent and filler dispersion method on the dielectric properties were examined for epoxy/clay nanocomposites. Irrespective of the clay dispersion method, relative permittivity and electrical conductivity are higher in the samples cured with the amine. Moreover, negative heterocharge accumulates in the vicinity of the anode in the amine-cured samples, whereas positive homocharge accumulates in the acid anhydride-cured samples. From the results of UV photon absorption and PL measurement, the bandgap or the energy at which the photon absorption increases drastically is smaller in the amine-cured samples than in the acid anhydride-cured samples. Ion migration can occur easily in the amine-cured samples whose electrical conductivity and relative permittivity are higher than the acid anhydride-cured samples. The curing agent gives the strongest effect, while the existence of clay affects secondly and the filler dispersion method has the weakest effect

Prevention of esophageal strictures after endoscopic submucosal dissection

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have recently been accepted as less invasive methods for treating patients with early esophageal cancers such as squamous cell carcinoma and dysplasia of Barrett\u27s esophagus. However, the large defects in the esophageal mucosa often cause severe esophageal strictures, which dramatically reduce the patient\u27s quality of life. Although preventive endoscopic balloon dilatation can reduce dysphagia and the frequency of dilatation, other approaches are necessary to prevent esophageal strictures after ESD. This review describes several strategies for preventing esophageal strictures after ESD, with a particular focus on anti-inflammatory and tissue engineering approaches. The local injection of triamcinolone acetonide and other systemic steroid therapies are frequently used to prevent esophageal strictures after ESD. Tissue engineering approaches for preventing esophageal strictures have recently been applied in basic research studies. Scaffolds with temporary stents have been applied in five cases, and this technique has been shown to be safe and is anticipated to prevent esophageal strictures. Fabricated autologous oral mucosal epithelial cell sheets to cover the defective mucosa similarly to how commercially available skin products fabricated from epidermal cells are used for skin defects or in cases of intractable ulcers. Fabricated autologous oralmucosal- epithelial cell sheets have already been shown to be safe

Epithelial-mesenchymal transition-converted tumor cells can induce T-cell apoptosis through upregulation of programmed death ligand 1 expression in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is an aggressive tumor, and it is urgently needed to develop novel therapeutic strategies including immunotherapy. In this study, we investigated the upregulation of the programmed death ligand 1 (PD-L1) due to epithelial-mesenchymal transition (EMT) in ESCC using an in vitro treatment system with the EMT inducer, glycogen synthase kinase (GSK)-3 inhibitor, and we also analyzed the correlation of EMT and PD-L1 expression in the clinical tumor samples of both tissue microarray (TMA) samples (n = 177) and whole tissue samples (n = 21). As a result, the inhibition of GSK-3β induces EMT phenotype with upregulated vimentin and downregulated E-cadherin as well as increased Snail and Zinc finger E box-binding homeobox (ZEB)-1 gene expression. Simultaneously, we showed that EMT-converted ESCC indicated the upregulation of PD-L1 at both protein (total and surface) and mRNA levels. Of importance, we showed that EMT-converted tumor cells have a capability to induce T-cell apoptosis to a greater extent in comparison to original epithelial type tumor cells. Furthermore, the immunohistochemical stains of ESCC showed that PD-L1 expression on tumor cells was positively correlated with EMT status in TMA samples (P = .0004) and whole tissue samples (P = .0029). In conclusion, our in vitro and in vivo study clearly demonstrated that PD-L1 expression was upregulated in mesenchymal type tumors of ESCC. These findings provide a strong rationale for the clinical use of anti-PD- 1/ anti-PD- L1 monoclonal antibodies for advanced ESCC patients

Inverse Proportionality of Thermal Conductivity and Complex Permittivity to Filler-Diameter in Epoxy Resin Composites with Silica

We prepared six kinds of epoxy resin nanocomposites with silica and an epoxy resin with no silica. The nanocomposites contain silica with different diameters (10, 50, and 100 nm) while their silica contents are 1, 5, 10, and 20 vol%. At 25 and 100 °C, the thermal conductivity has a nearly proportional dependence on the silica content and exhibits an almost reciprocal proportionality to the diameter of the silica. The latter result indicates that the interaction at filler-resin interfaces plays a significant role in heat transfer. However, this view contradicts an easy-to-understand thought that the filler-resin interfaces should work as a barrier for heat transfer. This in turn indicates that the interaction at filler-resin interfaces controls the bulk properties of the resin when the filler is in a nm size. Although the dielectric constant increases with the addition of the silica filler, its increment from the resin with no silica is the smallest in the resin with the 10-nm silica. Therefore, the addition of the 10-nm silica is adequate for electrical insulation purposes