1.625-μm high-power strained multiple quantum well lasers for optical time-domain reflectometers

An optical output power exceeding 210 mW has been achieved using 1.625-μm strained multiple quantum well lasers at a forward current of 800 mA under pulsed operation. We introduced tensile-strained barrier layers to increase internal quantum efficiency. High quantum efficiency is attributed to improved of hole injection efficiency and suppressed electron overflow from wells. The 1.625-μm high-power lasers are expected to be applied to optical time-domain reflectometers, which enable regular communication light to be used.     

ELECTROCHEMICAL ISOMERIZATION OF SULFINE

Abstract

Electrochemical isomerization of 1-phenyl-2, 2-dimethylpropane-1-thione S-oxide (phenyl-t-butylsulfine, E and Z form, 1a and 1b) was studied. Anodic isomerization of 1a gave the two isomers of the sulfine only, but cathodic reductive isomerization of 1a gave pivalophenone and 1-cyano-2-phenyl-3, 3-dimethyl-1-butene in addition to the E and Z isomers. This is the first example of an electrochemical reaction of a sulfine.     

Detection of small RNA molecules by a combination of branched rolling circle amplification and bioluminescent pyrophosphate assay

Polyfluorinated compounds (PFCs) are a relatively new and diverse set of compounds analyzed as contaminants in food. Their unique physical-chemical properties dictate the methods used for their analysis. Current analyses of the more volatile PFCs involve gas chromatography–mass spectrometry; liquid chromatography–tandem mass spectrometry is generally used for the less volatile PFCs. Considerations in the analysis of PFCs in foods include contamination from the widespread presence of materials that contain various PFCs, endogenous interfering compounds, and matrix effects. Future opportunities for research on PFCs in food exist, particularly in the areas of biological molecule–PFC interactions and the effects of food processing on these interactions. Future research will be facilitated by the synthesis of a wider variety of analytical standards.     

Colorimetric sensing of polyhydroxy compounds by an inclusion complex of boronic acid-modified amylose

A novel sensing method for polyhydroxy compounds has been established based on the stimuli-responsive inclusion complex of boronic acid-modified amylose with iodine. An aqueous solution containing the boronic acid-modified amylose and iodine was coloured bluish purple due to encapsulation of iodine within the helical cavity of amylose. When polyhydroxy compounds were added, the solution gradually lost its colour with increasing concentration of polyhydroxy compounds. This colour change was attributed to the dissociation of iodine from the amylose cavity in response to the polyhydroxy compounds. According to detailed examinations, it was concluded that the origin of the responsiveness is derived from an electrostatic repulsion between anionic boronate groups and iodine.     

Exponential homeomorphisms in the category of topological spaces with base point

Topologies on base point preserving function spaces are studied making use of the Brown-Booth-Tillotson C-smash product and the topologies on function spaces defined by the classes C of exponentiable spaces. Some conditions on the classes C are obtained for exponential bijections and exponential homeomorphisms in the category of topological spaces with base point. Conditions for exponential homeomorphisms are obtained for CW-complexes whose cellular structure implies precise results.     

Diastereoselective synthesis of all stereoisomers of beta-methoxytyrosine,a component of papuamides

beta-Methoxytyrosine (beta-OMeTyr) is a stereoundefined component of papuamides A and B, novel cyclodepsipeptides, with anti-HIV and cytotoxic activities. For structural determination and total synthesis of papuamides, all stereoisomers of beta-OMeTyr were stereoselectively prepared from (S)- and (R)-serine, respectively.     

Monoclonal-based enzyme-linked immunosorbent assay and immunochromatographic assay for enrofloxacin in biological matrices

Enrofloxacin has been increasingly used in veterinary medicine to treat microbial infections. A simple and reliable analytical method for this drug is required. The current determination by high performance liquid chromatography (HPLC) is sensitive but labor-intensive. This paper reports an enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody (MAb) and the development of a rapid test kit based on immunochromatography. The detection limits using the ELISA were 10 ppb for chicken liver and muscle, and 1 ppb for cattle milk, respectively. The mean recovery values were 77.3-96.0% for chicken liver, 72.4-92.0% for chicken muscle and 84.0-99.0% for cattle milk. The detection limits using the kit were ca. 100 ppb for chicken muscle and ca. 10 ppb for cattle milk, respectively. All ELISA results for assay of chicken liver, chicken muscle and cattle milk were confirmed using HPLC which is used as the routine assay. The HPLC (x) and ELISA (y) results showed close correlation for chicken liver (y = 8.7 + 0.85x, r2 = 0.99, n = 25), chicken muscle (y = -3.9 + 0.94x, r2 = 0.98, n = 25) and cattle milk (y = 18.4 + 0.92x, r2 = 0.99, n = 25).     

Lemnalol,a new sesquiterpenoid from the soft coral Lemnaliatenuis Verseveldt

The structure and absolute stereochemistry of lemnalol (1), a new ylangene-type sesquiterpenoid isolated from the soft coral $\text{Lemnalia}$$\text{tenuis}$ Verseveldt, has been established by spectroscopic, chemical, and x-ray crystallographic analyses.