Optical Coherence Tomography Implemented by Photonic Crystal Fiber

We report a photonic crystal fiber (PCF)-based optical coherence tomography (OCT) system, in which conventional single-mode fiber for the transmission line and the fiber coupler for the beam splitter/combiner are replaced with PCF and PCF coupler. The PCF coupler fabricated using the fused biconical tapered (FBT) method showed a nearly flat coupling ratio over a broad spectral bandwidth of 400 nm, which provided an axial resolution of 3-μm for OCT imaging. With a white-light source, the 8-μm thick air gap between two stacked cover glasses was measured, and with a conventional superluminecent diode (SLD) source, the in vitro images of rat eye and Misgurnus mizolepis skin were successfully obtained. The PCF and PCF coupler might enable a white-light as the source for the cost effective and high-resolution OCT system.     

Zero path-length difference interferometry using filter response of unbalanced interferometer to an amplified spontaneous emission beat noise spectrum

Zero path-length difference interferometry is demonstrated using the filter response of an unbalanced interferometer to the spontaneous/spontaneous beat noise spectrum of an amplified spontaneous emission source. The method is applicable to path-length differences ranging from a few centimeters to several kilometers.     

Spray dried calcium gelled arabinoxylan microspheres: A novel carrier for extended drug delivery

Arabinoxylan (AX) microspheres were formulated by ionotropic gelation for extended drug delivery. AX from Plantago ovata was tested for gelation with aluminium, barium, calcium, magnesium, and iron(III) chloride. Only calcium was found to lead to weak gelation with AX. The conventional needle extrusion produced fragile AX beads with calcium and hence the spray drying process was adopted for the preparation of metronidazole hydrochloride (MH) loaded AX microspheres. MH loading in AX microspheres was 30.8 mass %, 31.9 mass %, and 29.3 mass % in formulations gelled with 0.05 g, 0.1 g, and 0.15 g of calcium chloride per 100 mL of solution, respectively. Scanning electron microscopy revealed the crystallinity reduction of MH in microspheres. The surface of drug loaded calcium gelled AX microsphere was rougher than that of an ungelled one. Interactions of calcium with AX and the amorphous nature of the drug in the microspheres were evidenced by infrared spectroscopy and X-ray diffraction studies. Calcium-induced gelation can extend the drug release to over 90 min in 0.1 M HCl despite the hydrophilic nature of AX and the high solubility of metronidazole.     

Influence of surface characteristics of carbon blacks on cure and mechanical behaviors of rubber matrix compoundings

In this work, the effect of chemical modification on the surface energetics and cure kinetics of carbon blacks (CBs) modified with KOH and C6H6 was investigated by contact angle and rheometer measurements, respectively. Also, the resulting mechanical properties of the CBs/styrene-butadiene composites were studied in terms of tensile and dynamic mechanical analysis. As experimental results, the polar basic and nonpolar chemical treatments showed an increase of the London dispersive component (gamma(S)(L)) of gamma(S) of the CBs without significantly changing the surface properties and microstructures that resulted from the deaggregation of microstructures and decrease of the swollen weight of the sample in the equilibrium state. Also, it was clearly revealed that the increase of gamma(S) of the CBs could largely affect the vulcanization and mechanical properties of the composites, resulting from the increase in gamma(S)(L) of the CBs. These results were evident that the mechanical properties of the composites were controlled more by the gamma(S)(L) of gamma(S) than by the specific (or polar) component (gamma(S)(SP)), including electron acceptor and donor parameters on CB surfaces in an organic matrix composite system.     

The Incompressible Limits of Viscous Polytropic Fluids with Zero Thermal Conductivity Coefficient

ABSTRACT

We study the singular limit of viscous polytropic fluids without thermal conductivity as the Mach number tends to zero. A uniform existence result for the Cauchy problem in R ³ is proved under the assumption that the initial data belongs uniformly to H ^k (R ³) with k = 2, 3 and is well-prepared in H ¹ (R ³).     

Partial Hölder regularity for elliptic systems with non-standard growth

We study partial Hölder regularity for elliptic systems with non-standard growth. We consider general systems with Orlicz growth and discontinuous coefficient factor, for which we prove that their weak solutions are partially Hölder continuous for any Hölder exponents. In addition, we also obtain a similar result for systems with double phase growth.     

One-pot in situ fabrication of stable nanocaterpillars directly from polyacetylene diblock copolymers synthesized by mild ring-opening metathesis polymerization

We report a direct one-pot route for the preparation of supramolecules from simple polyacetylene diblock copolymers synthesized by mild ring-opening metathesis polymerization of cyclooctatetraene. This in situ nanoparticlization of conjugated polymer (INCP) approach is advantageous over conventional self-assembly processes because this method does not require any tedious postsynthetic treatments. Also, this direct approach provides intriguing supramolecules with a unique nanostructure resembling a caterpillar. Furthermore, the new supramolecules are highly stable adducts because the polyacetylene core block provides an exceptionally strong driving force for the self-assembly. Even though pristine polyacetylene is unstable in air, the polyacetylene segment in the nanocaterpillar is very stable because it is protected within the shell of the supramolecule.     

Highly enantioselective synthesis of (2S)-alpha-(hydroxymethyl)-glutamic acid by the catalytic Michael addition of 2-naphthalen-1-yl-2-oxazoline-4-carboxylic acid tert-butyl ester

[reaction: see text]. Highly enantioselective synthesis of a potent metabotropic receptor ligand, (2S)-alpha-(hydroxymethyl)-glutamic acid (2, HMG) was accomplished by the catalytic Michael addition of 2-naphthalen-1-yl-2-oxazoline-4-carboxylic acid tert-butyl ester (3b), using the phosphazene base, BEMP, in CH(2)Cl(2) at -60 degrees C in the presence of (S)-binaphthyl quaternary ammonium salt 4.