Near and vacuum ultraviolet absorption spectra of polycrystalline and amorphous evaporated films of naphthacene,pentacene, perylene and coronene

The near- and vacuum-ultraviolet absorption spectra of polycrystalline and amorphous films of naphthacene, pentacene, perylene evaporated on substrate at room and low temperatures have been measured at room temperature. The changes in the spectra are explained in terms of the loss of molecular orientation and the change in Davydov splitting. The spectra for coronene evaporated at room temperature are also reported.     

Novel drug delivery device using silicone: controlled release of insoluble drugs or two kinds of water-soluble drugs

Drug release mechanism from silicone carrier differs depending on physicochemical properties of the drug. So far, there have been few reports on controlled release of insoluble drug and on simultaneous release of two kinds of water-soluble drugs. The purposes of this study are to establish methods for (1). continuous release of insoluble drug, and (2). release of two kinds of water-soluble drugs from silicone carrier. Polystyrene beads (PSTB) and proteins such as interferon (IFN) and human serum albumin (HSA) were used as model drugs. PSTB was released from silicone only when citric acid (CA) and sodium bicarbonate (SB) existed as additives. The release patterns of IFN and HSA were almost same in the case of matrix and covered-rod formulations, but double-layered formulation released them in different patterns. As far as we are aware, this is the first report on the release of insoluble drug from silicone and the controlled release of two kinds of water-soluble drugs.     

Stereoselectivity in cycloaddition of phenylglyoxylonitrile oxide to 7-substituted norbornadienes and 8-substituted 2-azabicyclo[3.2.1]oct-3,6-dienes

The cycloaddition of phenylglyoxylonitrile oxide to the 7-substituted norbornadienes $\text{1}$a-c gives predominantly the endo isomers, but that to the 8-substituted 2-azabicyclo[3.2.1]oct-3,6-dienes $\text{2}$a,b the exo isomers.     

A self-consistent molecular field theory for aggregates of neutral molecules. I

A self-consistent theory is presented for aggregates of neutral molecules. According to the LCAO Hartree-Fock formalism a set of effective Hartree-Fock equations for molecules in the aggregate is derived. The molecular orbitals of each molecule are to be determined from the effective H-F equation for the molecule in which the interactions between the molecule and the surrounding ones are included as an intermolecular interaction field (molecular field). A self-consistent treatment leads to the molecular orbitals which are self-consistent with the molecular field. By this method, then-molecule problem becomesn times of one-molecule problem.     

Langmuir monolayers and the transferred films of fluorinated amphiphiles containing vinyl groups

The monolayer behavior of long-chain esters of acrylic and methacrylic acids containing perfluoro or partially fluorinated carbon chains at the air/water interface was studied by surface pressure-area isotherm measurements and Brewster angle microscopy. It has been found that a minor change in the chemical structures of these fluorinated amphiphiles, such as a hydrogen substituted at the omega-position of the hydrophobic fluorocarbon tails instead of a fluorine as well as hydrophilic vinyl ester groups inserted between acrylates and methacrylates, induces a drastic change in the isotherms for the monolayers, suggesting different molecular orientation and packing in the films. The monolayers were transferred by horizontal lifting, Langmuir-Blodgett, and surface-lowering methods to give the X-, Y-, and Z-type films, respectively. These films were characterized by scanning probe microscopy, to clarify the mesoscopic surface structures of the molecular films exposed with the hydrophilic or hydrophobic moieties in air, depending upon the dipping methods. The Z-type films with the outermost surface of the fluorinated substituents were examined in relation to the frictional properties that strongly depend upon the fluorine and the hydrogen atoms at the end of the hydrophobic fluorocarbon chains, which is controllable at the atomic level.     

Dimeric copper(II) trimethylsilyl­acetate adducts with pyridine, 2‐­methylpyridine, 3‐methylpyridine and quinoline,and a polymeric copper(II) trimethylsilylacetate

In the crystals of bis(pyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₅H₅N)₂], (I), the dinuclear Cu^II complexes have cage structures with Cu?Cu distances of 2.632 (1) and 2.635 (1) Å. In the crystals of bis(2‐­methylpyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₆H₇N)₂], (II), bis­(3‐methylpyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₆H₇N)₂], (III), and bis(quinoline‐N)­tetrakis(μ‐­trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₉H₇N)₂], (IV), the centrosymmetric dinuclear Cu^II complexes have a cage structure with Cu?Cu distances of 2.664 (1), 2.638 (3) and 2.665 (1) Å, respectively. In the crystals of catena‐poly­[tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II)], [Cu₂(C₅H₁₁O₂Si)₄]_n, (V), the dinuclear Cu^II units of a cage structure are linked by the cyclic Cu—O bonds at the apical positions to form a linear chain by use of a glide translation.     

A Sensitive Colorimetric Method for the Determination of Arsenic in Environmental and Biological Samples

Results of a thorough study and application of leucocrystal violet for the determination of arsenic in parts per million (ppm) levels in environmental and biological samples is described here. The proposed method is based on the reaction of arsenic with potassium iodate to liberate iodine. The liberated iodine selectively oxidises leucocrystal violet to form crystal violet dye in the presence of sodium hydroxide. The dye formed shows maximum absorbance at 592 nm. The detection limit of arsenic is 0.002 μgmL^?1 and the method obeys Beer's law over the concentration range of 0.1 μg - 1.0 μg of per 25 mL of final solution (0.004–0.04 ppm). The molar absorptivity was found to be 1.49 × 10⁶ L mol^?1 cm^?1. The proposed method was successfully applied for the determination of arsenic in various environmental and biological samples. The results are in good agreement with the standard reported method.     

An Integrated Circuit for Two-Dimensional Edge-Detection with Local Adaptation Based on Retinal Networks

We designed an integrated circuit for edge detection of a two-dimensional image based on the vertebrate outer retina, which has wide dynamic range in image processing. The unit circuit is simple, and operates as a current-mode analog metal-oxide-semiconductor (MOS) circuit. In order to extract edges from an image composed of bright and dark domains, the circuit realizes a function called local adaptation in which the sensitivity adapts to local brightness of the image. Simulation results, using the simulation program with integrated circuit emphasis (SPICE), of two-dimensional Gaussian-distributed images in which the intensity ranged over four orders of magnitude, showed the local adaptation. As a result, the intensity of output images was in the range of one order of magnitude. Furthermore, as the simulation result of real images, it was shown that edges in the dark domain, which was five times darker than the bright domain, were successfully detected as the bright domain in which input photocurrents ranged over two orders of magnitude.     

Analog Integrated Circuit for Motion Detection with Simple-Shape Recognition Based on Frog Vision System

We proposed in this research a novel two-dimensional network based on the frog visual system, with a motion detection function and a newly developed simple-shape recognition function, for use in object discrimination by integrated circuits. Specifically, the network mimics the signal processing of the small-field cell in a frog brain, consisting of the tectum and thalamus, which generates signals of the motion and simple shape of an object. The proposed network is constructed from simple analog complementary metal oxide semiconductor (CMOS) circuits; a test chip of the proposed network was fabricated with a 1.2 μm CMOS process. Measurements on the chip clarified that the proposed network can generate signals of the moving direction, velocity, and simple shape, as well as perform information processing of the small-field cell. Results with the simulation program with integrated circuit emphasis (SPICE) showed that the analog circuits used in the network have low power consumption. Applications of the proposed network are expected to realize advanced vision chips with functions such as object discrimination and target tracking.