Synthesis, Structural Characterization, and Preliminary Biological Characterization of Organotin Polyethers Derived from Hydroquinone and Substituted Hydroquinones

A variety of dibutyltin polyethers have been synthesized employing the interfacial polymerization technique. The products are polymers with degrees of polymerization ranging from 60 to 390. Infrared spectral and mass spectral results are consistent with the proposed structure. The products show good inhibition of a variety of cancer cells including those associated with bone, breast, prostrate, and lung cancers. Some also show good viral inhibition of the HSV-1 (herpes simplex) and Vaccina (small pox) viruses with those derived from electron rich hydroquinone derivative being most active. Hydroquinone-derived polymers containing electron withdrawing groups exhibit inhibition of a variety of gram positive and gram negative bacteria.     

Visual clarity and feeling of contrast

The visual clarity of a lighting environment is significantly affected by changing the general color rendering index (Ra) of its illumination. This effect has been studied by a number of researchers, but the cause of this effect has not been thoroughly studied. In order to clarify this, the mutual relations between visual clarity, lightness perception, and feeling of contrast are analyzed by using object colors under illuminations with various Ra values. the results obtained are as follows. (1) the visual clarity of a lighting environment is different from the lightness perception of the object colors in the environment. (2) the change in visual clarity of a lighting environment is highly correlated to a feeling of contrast between object colors under the illumination. (3) the effect of visual clarity is estimated effectively by assessing the feeling of contrast using a specially selected four-color combination. (4) the illuminance for equal visual clarity for any illumination is predicted by the equality of feeling of contrast under the same illumination specified by the gamut area made by the component colors of the four-color combination in a brightness and colorfulness space. (5) the effect of visual clarity under various illuminations cannot be predicted by using their Ra values.     

Relationship between brightness/luminance ratio and additivity‐law failure

The degree of additivity‐law failure of a mixture color consisting of two component chromatic colors has very complex characteristics depending on the used component colors and their mixing conditions. It is significantly affected by the mixture‐color chromaticity and by the brightness/luminance ratio at the chromaticity. A simple relationship was derived between the following quantities: degree of additivity‐law failure, additivity‐law luminance (luminance of the mixture color derived by postulating additivity law), and brightness/luminance ratio at the chromaticity of the mixture color. This relationship can be applied to any additivity‐law failure experiment and any formula on brightness/luminance ratio. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 185–190, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/col.10045     

Chemical composition of silages treated with some volatile fatty acids,with special reference to the changes in sugars

In eight separate experiments with laboratory silos, silages were prepared with 50 mmol caproic (nC₆), isocaproic (iC₆), valeric (nC₅) and isovaleric (iC₅) acid additions per kg Italian ryegrass or cocksfoot, and stored at 25°C for 70 days. In the nC₆ and iC⁶ treatments, fermentation was consistently inhibited, and also the contents of water-soluble carbohydrates (WSC) were considerably higher in the silages than in the grasses. This increase in WSC was partly explained by the increase in glucose but the difference between WSC and “glucose + fructose” was clearly larger in the silages than in the grasses. In the nC₅ and iC⁵ treatments, various results were obtained; in some cases, presumably due to high dry matter content, fermentation was inhibited and WSC increased, while, in one case, fermentation was improved with higher lactic acid and lower butyric acid production than in the control silage. According to the results of five experiments with bag silos, although the inhibition of fermentation was observed by the treatment with nC₆, little or no increase in WSC during ensilage was found.     

High-performance genetic analysis on microfabricated capillary array electrophoresis plastic chips fabricated by injection molding

We have developed a novel technique for mass production of microfabricated capillary array electrophoresis (mu-CAE) plastic chips for high-speed, high-throughput genetic analysis. The mu-CAE chips, containing 10 individual separation channels of 50-microm width, 50-microm depth, and a 100-microm lane-to-lane spacing at the detection region and a sacrificial channel network, were fabricated on a poly(methyl methacrylate) substrate by injection molding and then bonded manually using a pressure-sensitive sealing tape within several seconds at room temperature. The conditions for injection molding and bonding were carefully characterized to yield mu-CAE chips with well-defined channel and injection structures. A CCD camera equipped with an image intensifier was used to monitor simultaneously the separation in a 10-channel array with laser-induced fluorescence detection. High-performance electrophoretic separations of phiX174 HaeIII DNA restriction fragments and PCR products related to the human beta-globin gene and SP-B gene (the surfactant protein B) have been demonstrated on mu-CAE plastic chips using a methylcellulose sieving matrix in individual channels. The current work demonstrated greatly simplified the fabrication process as well as a detection scheme for mu-CAE chips and will bring the low-cost mass production and application of mu-CAE plastic chips for genetic analysis.     

Remote sensing of mechanical properties of materials using a novel ultrasound transducer and signal processing

An ultrasound-based remote sensing method to evaluate the mechanical properties of materials is presented. This method consists of a disk-shaped, piezoelectric transducer, operating at its resonance frequency, and a phase-shifted, feedback circuit. Mechanical parameters are derived by analyzing the signal contained in the phase-shifted values of the reflected signal. It is concluded that, using this novel transducer system and signal processing, remote mechanical measurements can be made. Such measurements obviate the need to apply the force-deformation approach and may be used to enable stiffness imaging.     

Role of free cadmium and selenium ions in the potential mechanism for the enhancement of photoluminescence of CdSe quantum dots under ultraviolet irradiation

The present study describes an enhancement of the photoluminescence of CdSe quantum dots under long-term ultraviolet irradiation in organic solvents. The photoenhancement effect followed multiexponential kinetics and was found to depend on several factors: intensity of ultraviolet light, polarity of the solvent, presence of capping agents on the nanocrystal surface, and presence of free Cd and Se ions in the solution. High intensity ultraviolet irradiation provoked a rapid enhancement of the photoluminescence of CdSe nanocrystals, reaching the maximum with subsequent photoluminescence decay. Low-intensity ultraviolet irradiation provoked a comparatively slow enhancement of the photoluminescence of CdSe nanocrystals, reaching saturation after 5-6 hours of irradiation in organic solvents (butanol and chloroform). The photoenhancement effect was reversible or irreversible depending on the additional ingredients. The role of free Cd and Se in these processes was clarified. The results are discussed in the context of ultraviolet induced liberation of free Cd and Se ions from the nanocrystal surface and their hypothetical reversible deposition with trapping of the surface holes and influencing the efficiency of radiative versus nonradiative exciton decay during the enhancement of photoluminescence.