A simple, fast, and easy assay for transition metal-catalyzed coupling reactions using a paper-based colorimetric iodide sensor

A paper-based colorimetric iodide sensor (PBCIS) that consists of filter paper treated with starch and an oxidant is developed. It has been employed as a protocol to obtain the extent of conversion of aryl iodides in C-C, C-N, C-O and C-S bond formations, including polymer-supported Heck reactions, by transition metal catalysts such as palladium, nickel and copper.     

A bi-ligand co-functionalized gold nanoparticles-based calcium ion probe and its application to the detection of calcium ions in serum

In this study, the use of bi-ligand co-functionalized gold nanoparticles in a highly selective and sensitive colorimetric probe for Ca(2+) ions is demonstrated and this probe also determined the concentrations of Ca(2+) ions in serum samples.     

Heat Treatment of the Photonic Crystal Fiber

We report heat treatment of the photonic crystal fiber. As the temperature was increased, the transmission of the photonic crystal fiber was increased, unlike conventional single mode fiber. The transmission increase at short wavelength region was larger than long wavelength region for the various temperatures. After crystallization of the silica glass, the spectra of the photonic crystal fiber were just decreased at all wavelength regions, but, in case of the single mode fiber, the absorption in visible region around 450 nm increased with increasing temperature.     

Novel Optical Delay Line for Optical Coherence Tomography System

A novel all-fiber optical delay line for an advanced optical coherence tomography (OCT) system is proposed. Using the distributed reflectance characteristic of a chirped fiber Bragg grating (CFBG), the optical delay can be obtained without leaving the fiber that forms the system. The proposed delay line consists of a pair of identical CFBGs. The gratings are cascaded in reverse order to cancel the inherent wavelength dependency of CFBGs. Tunable optical delay is obtained by applying small strain on one of the CFBGs through an attached piezo actuator. The small displacement induced by the piezo actuator is amplified by a factor of up to 100 due to the distributed reflectance characteristic of the CFBGs. This principle and characteristics of the proposed optical delay line are analyzed in detail.     

Acoustic hybrid junction in a rectangular waveguide

Acoustic scattering from a hybrid junction in a rectangular waveguide is studied. The Fourier transform and mode matching is used to represent the scattered wave and the simultaneous equations for the modal coefficients are formulated. A residue calculus is utilized to obtain a solution to the simultaneous equations in fast-converging series. Numerical computations are performed to show the behavior of transmission in terms of junction geometry and operating frequency. The utility of acoustic hybrid junction is discussed in terms of its decoupling characteristics.     

Application of Yeast Candida utilis to Ferment Eisenia bicyclis for Enhanced Antibacterial Effect

In this study, fermentation broth of Eisenia bicyclis with Candia utilis YM-1 exhibited enhanced antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) and food-borne pathogenic bacteria. To perform a more detailed investigation on the antibacterial activity, the fermented broth of E. bicyclis was extracted with methanol and further fractionated with organic solvents. After 1-day fermentation, the ethyl acetate (EtOAc)-soluble extract exhibited the highest anti-MRSA activity with minimum inhibitory concentration values ranging from 128 to 512 μg/mL, suggesting that the fermentation of E. bicyclis with C. utilis YM-1 may enhance antibacterial activity against MRSA. This effect was correlated to the result obtained by an increase in total phenolic contents in EtOAc-soluble extract. In addition, high-performance liquid chromatography analysis revealed that eckol, dieckol, dioxinodehydroeckol, and phlorofucofuroeckol-A contents in the EtOAc-soluble extract increased significantly. Thus, these results show that anti-MRSA activity of E. bicyclis fermented with C. utilis most likely originated from phlorotannins and allow the possible application of a variety of seaweed functional foods.     

Coherent Brillouin spectroscopy in a strongly scattering liquid by picosecond ultrasonics

In a modification of a picosecond ultrasonic technique, a short acoustic pulse is launched into a liquid sample by a laser pulse absorbed in a semitransparent transducer film and is detected via coherent Brillouin scattering of a time-delayed probe pulse. With both excitation and probing performed from the transducer side, the arrangement is suitable for in vivo study of biological tissues. The signal is collected from a micrometer-thick layer next to the transducer and is not affected by the diffuse scattering of probe light deeper in the sample. The setup, utilizing a 33 nm thick single crystal SrRuO(3) transducer film, is tested on a full fat milk sample, with 11 GHz acoustic frequency recorded.     

Removal and recovery of mercury from aqueous solution using magnetic silica nanocomposites

Thiol-functionalized magnetic silica nanocomposite was synthesized and tested for its mercury pick-up capability in aqueous solution. Magnetic property was to be utilized upon the collection of the adsorbents and the recovery adsorbed Hg by subsequent separation process. Cobalt ferrite nanoparticle, the core of magnetic silica nanocomposite, was synthesized using a thermal decomposition method and grown to a particle having an average size of 13 nm. The dispersed nanoparticles were then further arranged into spherical groups using a nanoemulsion method to enhance the reactivity toward magnets followed by tetraethyl orthosilicate coating using a modified Stöber method. The pore structure was modified by an additional coating of cetyltrimethylammonium bromide and tetraethyl orthosilicate. Finally, the surface of the magnetic silica nanocomposite was functionalized with thiol group. When tested for mercury adsorption capacity, a sufficiently high Hg adsorption capacity of 19.79 mg per g of adsorbent was obtained at room temperature and a pH of 5.5.