A TM-Pass/TE-Stop Polarizer Based on a Surface Plasmon Resonance

A TM-pass/TE-stop polarizer consisting of a metal film sandwiched between dielectric gratings is investigated using the finitedifferencetime-domain method. At normal incidence with respect to the grating plane, a transmissivity of more than 94% anda reflectivity of more than 98% are obtained at λ = 1.55 μm for the TM and TE waves, respectively. The extinction ratio is morethan 17 dB over a wavelength range of 1.50 μm to 1.75μm. A high extinction ratio is maintained at oblique incidence, although thewavelength range shifts towards longer wavelengths. The TM-pass/TE-stop operation is also achieved with a modified structure,in which a dielectric grating is sandwiched between metal films.1. IntroductionThere are a great number of papers devoted to the studyof light propagation in periodic structures [1]. One ofthe important applications of the periodic structures is toconstruct a polarizer, which is used in optical communicationsand sensing devices. Recently, high transmission of thetransverse magnetic (TM) wave through a thin metal filmhas been suggested and discussed [2?4]. The transmission isclosely related to a surface plasmon (SP) resonance [5]. TheSP resonance is realized using a thin metal film sandwichedbetween dielectric gratings. We should also note that recentinterest has been directed toward plasmon waveguidesoperating at λ = 1.55 μm (optical communication band)[6, 7].In this paper, the SP-based enhanced transmissionthrough a thin metal film is investigated in more detail inthe optical communication band. The finite-difference timedomain(FDTD) method is used for the analysis. To obtaina high

Characterizations of a neutralizing antibody broadly reactive to multiple gluten peptide:HLA-DQ2.5 complexes in the context of celiac disease

Abstract In human celiac disease (CeD) HLA-DQ2.5 presents gluten peptides to antigen-specific CD4+ T cells, thereby instigating immune activation and enteropathy. Targeting HLA-DQ2.5 with neutralizing antibody for treating CeD may be plausible, yet using pan-HLA-DQ antibody risks affecting systemic immunity, while targeting selected gluten peptide:HLA-DQ2.5 complex (pHLA-DQ2.5) may be insufficient. Here we generate a TCR-like, neutralizing antibody (DONQ52) that broadly recognizes more than twenty-five distinct gluten pHLA-DQ2.5 through rabbit immunization with multi-epitope gluten pHLA-DQ2.5 and multidimensional optimization. Structural analyses show that the proline-rich and glutamine-rich motif of gluten epitopes critical for pathogenesis is flexibly recognized by multiple tyrosine residues present in the antibody paratope, implicating the mechanisms for the broad reactivity. In HLA-DQ2.5 transgenic mice, DONQ52 demonstrates favorable pharmacokinetics with high subcutaneous bioavailability, and blocks immunity to gluten while not affecting systemic immunity. Our results thus provide a rationale for clinical testing of DONQ52 in CeD

Wogonin Induces Reactive Oxygen Species Production and Cell Apoptosis in Human Glioma Cancer Cells

Glioma is the most common primary adult brain tumor with poor prognosis because of the ease of spreading tumor cells to other regions of the brain. Cell apoptosis is frequently targeted for developing anti-cancer drugs. In the present study, we have assessed wogonin, a flavonoid compound isolated from <em>Scutellaria baicalensis</em> Georgi, induced ROS generation, endoplasmic reticulum (ER) stress and cell apoptosis. Wogonin induced cell death in two different human glioma cells, such as U251 and U87 cells but not in human primary astrocytes (IC 50 > 100 μM). Wogonin-induced apoptotic cell death in glioma cells was measured by propidine iodine (PI) analysis, Tunnel assay and Annexin V staining methods. Furthermore, wogonin also induced caspase-9 and caspase-3 activation as well as up-regulation of cleaved PARP expression. Moreover, treatment of wogonin also increased a number of signature ER stress markers glucose-regulated protein (GRP)-78, GRP-94, Calpain I, and phosphorylation of eukaryotic initiation factor-2α (eIF2α). Treatment of human glioma cells with wogonin was found to induce reactive oxygen species (ROS) generation. Wogonin induced ER stress-related protein expression and cell apoptosis was reduced by the ROS inhibitors apocynin and NAC (<em>N</em>-acetylcysteine). The present study provides evidence to support the fact that wogonin induces human glioma cell apoptosis mediated ROS generation, ER stress activation and cell apoptosis