Electrical conductance of solutions of lithium nitrate in 1,3-diaminopropane

Electrical conductances and densities of the LiNO₃-1,3-diaminopropane system have been measured as a function of composition and temperature. The results suggest that the solvent molecules may act as bridges between Li⁺ ions at higher concentration of LiNO₃.     

Determination of midodrine in human plasma by high-performance liquid chromatography with fluorescence detection.

A simple and sensitive fluorometric high-performance liquid chromatographic method was developed for the determination of midodrine in human plasma. After liquid-liquid extraction from plasma, the drug and 2-phenylglycinol (internal standard) were convened into the corresponding fluorescent derivatives by reaction with 3,4-dihydro-6,7-dimethoxy-4-methyl-3-oxoquinoxaline-2-carbonyl chloride, a fluorescence derivatization reagent for amines. The derivatives were separated within 30 min on a reversed-phase column using isocratic elution with acetonitrile-methanol-water (10:30:60, v/v) and were detected spectrofluorometrically at 485 nm with excitation at 400 nm. The detection limit for midodrine was 0.3 pmol (76 pg) per mL plasma at a signal-to-noise ratio of 3.     

Simultaneous Measurement of Droplet Size and Three-Components of Velocity in Spray

The combination of the optical diagnostics and image processing technique has produced various methods of practical measurement in engineering. The measurement of size and velocity of droplets in fuel spray is one typical example. In general, the spray is a complicated and three-dimensional two-phase flow; therefore multi-dimensional field measurement of the spray field is indispensable. In the present paper, a technique of simultaneous measurement of droplet size and three-components of velocity is proposed and applied to spray issuing from the swirl nozzle as a practical application. The focused image of glare points is captured by a stereoscopic arrangement, and droplet size and the three-components of velocity are evaluated from the doublet image. Fundamental optical arrangements to capture the image of the glare points with a stereo view are established, and the feasibility and the accuracy of the technique are confirmed. © 2004 The Optical Society of Japan     

Genetically Encoded Bioluminescent Indicator for ERK2 Dimer in Living Cells

In this study, a genetically encoded bioluminescent indicator for ERK2 dimer was developed with the split Renilla luciferase complementation method, in which the formation of ERK2 dimer induces a spontaneous emission of bioluminescence in living cells. In response to extracellular stimuli, such as epidermal growth factor (EGF) or 17β‐estradiol (E2), extracellular signal‐regulated kinase 2 (ERK2) is phosphorylated by its upstream kinase MEK, and also phosphorylates its substrates in various regions of the cell, including the nucleus. Phosphorylated ERK2 is led to form its dimer, thereby transporting itself into the nucleus. We demonstrated with the indicator that stimulation with EGF or E2 induces the formation of ERK2 dimer in living MCF‐7 cells. The dynamics of this dimer formation was examined and discussed.     

Analysis of tetracycline antibiotics using HPLC with pulsed amperometric detection.

The analysis of tetracycline, oxytetracyline, chlortetracycline and doxycycline by high-performance liquid chromatography with pulsed amperometric detection using an anodized boron-doped diamond thin film (BDD) electrode is originally reported. The analyses were carried out using the mobile phase, phosphate buffer (0.01 M, pH 2.5)-acetonitrile (80:20; v/v), on a C18 column (250 x 4.6 mm i.d., 5 microm) at a flow rate of 1.0 mL/min. The optimal PAD waveform parameters at the anodized BDD were 1.5 V (versus Ag/AgCl) detection potential (E(det)) for 290 ms (200 ms delay time and 90 ms integration time), 2.0 V (versus Ag/AgCl) oxidation potential (E(oxd)) for 200 ms oxidation time (t(oxd)) and 0.4 V (versus Ag/AgCI) reduction potential (E(red)) for 200 ms reduction time (t(red)). The proposed method showed the simultaneous determination of tetracycline, oxytetracyline, chlortetracycline and doxycycline with a linear range of 0.1 - 100 microg/mL, detection limits of 0.05 - 0.1 microg/mL and recoveries of 70.8 - 96.0%. The application of this method to real samples was demonstrated and validated using a shrimp sample.     

Preparation and characterization of macroporous polystyrene resins containing ethynyl groups and transition metal acetylide complexes

Ethynylated polystyrene resins were prepared as functionalized polymer supports by the iodination reaction of macroporous polystyrene resins and reacted with transition metal diethynyl complex (Mt = Ni) and metal halides (Mt = Rh, Pd, and Pt) in a basic solvent using cuprous iodide as a catalyst to obtain macroporous polystyrene resins containing organotransition metals. The distribution of the metal acetylide complexes in the modified macroporous resins was determined by an electron probe microanalyzer. A gradient in the transition metal distribution was observed in any case of the modified resins. The stability of the organotransition metal complexes in the polymer matrix could be compared with a low molecular weight analogous complex quantitatively.     

Effect of the pore surface modification of an inorganic substrate on the plasma‐grafting behavior of pore‐filling‐type organic/inorganic composite membranes

We have investigated the effect of the surface state and surface treatment of the pores of an inorganic substrate on the plasma‐grafting behavior of pore‐filling‐type organic/inorganic composite membranes. Shirasu porous glass (SPG) was used as the inorganic substrate, and methyl acrylate was used as the grafting monomer. The grafting rate increased as the density of silanol on the SPG substrate increased. This result suggests that radicals are generated mainly at the silanol groups on the pore surface by plasma irradiation. The SPG substrates were treated with silane coupling agents used to control the mass of organic material bonded to the pore surface. The thickness of the grafted layer became thinner as the mass of organic material bonded to the pore surface of SPG increased. This decrease in the thickness of the grafted layer could be explained by the decrease in the penetration depth of vacuum ultraviolet rays contained in plasma having a wavelength of less than 160 nm that generated radicals in the pores of the substrate. The thickness of the grafted layer inside the SPG substrates could be controlled through the control of the mass of organic material bonded to the pore surface of the SPG substrate. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 846–856, 2006     

Simultaneous imaging of the structure and fluorescence of a supramolecular nanostructure formed by the coupling of π‐conjugated polymer chains in the intermolecular interaction

We fabricated a micrometer‐long supramolecular chain in which π‐conjugated polyrotaxane was coupled. A new experimental setup was designed and constructed, and the simultaneous direct imaging of the structure and fluorescent function was achieved. Furthermore, we identified the formation of a polymer intertwined network and observed novel fluorescence due to a long‐range interaction via this intertwined network over a distance of 5 μm or more without quenching over 15 min in the near field. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 801–809, 2006