We present a detailed study of the effect of planar stacking disorder on optical properties of inverted opal photonic crystals. Systems with periodic stacking sequences are first studied that include face centered cubic, hexagonal close-packed, and doubly hexagonal close-packed photonic crystals. For the structures with periodic stacking order, we evaluate the band structure followed by calculation of transmission spectrum along the direction perpendicular to the hexagonal close-packing plane of the structures. Inverted opal photonic crystals with random stacking sequences are then studied by calculating average transmittance of the photonic crystal slabs over various random stacking configurations. The position and width of the lowest stop gap along the direction normal to the hexagonal close-packing plane is found to be invariant, regardless of the stacking sequence in the photonic crystal. We show how the propagation properties at higher frequencies are affected by the stacking configurations (both periodic and disordered stacking sequences), particularly those near the edges of the absolute band gap. The obtained results are directly relevant to transmission/reflection experiments on inverted opal photonic crystals with complete band gap.
In this paper, we propose an object-aware holistic superpixel selection (HPS) method to automatically select the discriminative superpixels of an image for image classification purpose. Through only considering the selected superpixels, the interference of cluttered background on the object can be alleviated effectively and thus the classification performance is significantly enhanced. In particular, for an image, HPS first selects the discriminative superpixels for the characteristics of certain class, which can together match the object template of this class well. In addition, these superpixels compose a class-specific matching region. Through performing such superpixel selection for several most probable classes, respectively, HPS generates multiple class-specific matching regions for a single image. Then, HPS merges these matching regions into an integral object region through exploiting their pixel-level intersection information. Finally, such object region instead of the original image is used for image classification. An appealing advantage of HPS is the ability to alleviate the interference of cluttered background yet not require the object to be segmented out accurately. We evaluate the proposed HPS on four challenging image classification benchmark datasets: Oxford-IIIT PET 37, Caltech-UCSD Birds 200, Caltech 101, and PASCAL VOC 2011. The experimental results consistently show that the proposed HPS can remarkably improve the classification performance.
We have recently reported the growth of freestanding, single-crystal, seamless nanorings of zinc oxide via a spontaneous self-coiling process during the growth of polar-nanobelts [X.Y. Kong et al., Science 303, 1348 (2004)]. The nanoring is made by coaxial and uniradius loop-by-loop winding of a fine ZnO nanobelt. An important fact is that each and every nanoring is made of a nanobelt that contains basal-plane planar defects, which are suggested to be important for leading the fastest growth of the nanobelt as well as lowering its elastic deformation energy. In this paper, high-resolution transmission electron microscopy is applied to investigate the nature of the planar defects in the nanobelts and in nanorings. The planar defects were initiated and formed by single-layer segregation of the doping element, such as indium, which was introduced in the growth process. The accumulation of impurity ions forms two vicinal $\mathrm{In}\mathrm{O}$ octahedral layers parallel to the basal plane. They form ``head-to-head'' and ``tail-to-tail'' polar-inversion domain boundaries. For a nanobelt that self-coils into a nanoring, we found that the head-to-head and tail-to-tail polar-inversion domain boundaries are paired, thus, the polarity of the nanobelt is unchanged. Therefore, our data support the proposed model [X.Y. Kong et al., Science 303, 1348 (2004)] that the nanoring is initiated by circularly folding a nanobelt due to long-range electrostatic interaction between the surface polar charges on the two sides, and a loop-by-loop winding of the nanobelt forms a complete ring.
11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyzes the interconversion of inactive cortisone to active cortisol in a NADPH dependent manner. Excess cortisol or 11β-HSD1 leads to insulin resistance and metabolic syndrome. Inhibition of 11β-HSD1 activity has been pursued vigorously by the pharmaceutical industry as a potential therapeutic strategy for the treatment of type 2 diabetes. As a result, a large number of chemical classes have been identified as potent and selective small molecule inhibitors for 11β-HSD1. Here we review the recent progress in the discovery and development of small molecule inhibitors of 11β-HSD1 by highlighting the medicinal chemistry, SAR, in vivo pharmacodynamic effects and efficacy of a few representative classes of inhibitors in models of diabetes. Furthermore, we also review the structural characteristics of each class of inhibitors by analyzing the inhibitor co-crystal structures of 11β- HSD1. Keywords: 11β-HSD1, 11β-HSD2, metabolic syndrome, type 2 diabetes, sulfonamide, amide, triazole, insulin resistance, SAR, pharmacodynamic effects, efficacy, co-crystal structures, Glucocorticoids, anti-inflammatory hormones
A new chaotic system is built which is consists of two subsystems. A subsystem is analyzed such as equilibrium, eigenvalue, Lyapunov, dimension and Lyapunov exponent. A practical circuit is designed to realize the system and the experimentation is carried out. The manifold chaotic attractor of the two subsystems is observed in the oscillograph, it is good agree with simulation.