Modification of Photorefractive Waveguides in Lithium Niobate by Guided Beam for Optical Dynamic Interconnection

We investigate experimentally and numerically a novel method of modifying photorefractive waveguides in a lithium niobate crystal by a guided beam. The guided beam with a strong optical power can change the refractive index of the photorefractive waveguide because of the photorefractive effect. The modification of waveguide structure can be utilized for optical dynamic interconnection. Changes of optical characteristics of a probe beam caused by a modification beam are investigated. Experimental results show that the transmitted power or the peak intensity of the probe beam decreases exponentially as a function of total exposure energy of the modification beam. We also numerically analyze the refractive index change caused by the modification beam in the photorefractive waveguide. The numerical results show good agreement with the experimental results.     

Optical retrieval of encrypted digital holograms for secure real-time display

Secure data transmission by use of encrypted digital holograms and an optical retrieval system for secure real-time display are proposed. Original images are encrypted by a double-random phase encryption technique and then are recorded as digital holograms in a CCD, together with a reference plane wave. This digital hologram of the encrypted image can be transmitted to receivers via any conventional electronic or digital communication channels. The decryption key is also recorded as a digital hologram. At the receiver, the original image can be retrieved by an optical correlation-based reconstruction process. Both encryption and retrieval can be performed by all-optical means, and thus a real-time secure display can be implemented. We demonstrate the proposed system numerically and experimentally.     

Three-dimensional motion-picture imaging of dynamic object by parallel-phase-shifting digital holographic microscopy using an inverted magnification optical system

Optical Review - We constructed a parallel-phase-shifting digital holographic microscopy (PPSDHM) system using an inverted magnification optical system, and succeeded in three-dimensional (3D)...     

Ketene-S,N-acetals as Synthetic Intermediates for Heterocycles. A New Synthesis of 4-Arylaminopyrimidines

Reaction of β-aminothiocarbonyl-α-methylthioenamines (3a-d) derived from ketene-S, N-acetal (1) with benzamidine and guanidine gave 4-arylamino-pyrimidines (4a-d and 5a-d), respectively.     

Correlation analyses on binding affinity of sialic acid analogues and anti-influenza drugs with human neuraminidase using ab initio MO calculations on their complex structures--LERE-QSAR analysis (IV)

We carried out full ab initio fragment molecular orbital (FMO) calculations for complexes comprising human neuraminidase-2 (hNEU2) and sialic acid analogues including anti-influenza drugs zanamivir (Relenza) and oseltamivir (Tamiflu) in order to examine the variation in the observed inhibitory activity toward hNEU2 at the atomic and electronic levels. We recently proposed the LERE (linear expression by representative energy terms)-QSAR (quantitative structure-activity relationship) procedure. LERE-QSAR analysis quantitatively revealed that the complex formation is driven by hydrogen-bonding and electrostatic interaction of hNEU2 with sialic acid analogues. The most potent inhibitory activity, that of zanamivir, is attributable to the strong electrostatic interaction of a positively charged guanidino group in zanamivir with negatively charged amino acid residues in hNEU2. After we confirmed that the variation in the observed inhibitory activity among sialic acid analogues is excellently reproducible with the LERE-QSAR equation, we examined the reason for the remarkable difference between the inhibitory potencies of oseltamivir as to hNEU2 and influenza A virus neuraminidase-1 (N1-NA). Several amino acid residues in close contact with a positively charged amino group in oseltamivir are different between hNEU2 and N1-NA. FMO-IFIE (interfragment interaction energy) analysis showed that the difference in amino acid residues causes a remarkably large difference between the overall interaction energies of oseltamivir with hNEU2 and N1-NA. The current results will be useful for the development of new anti-influenza drugs with high selectivity and without the risk of adverse side effects.     

A novel plant growth regulator from Pholiota lubrica

Nine compounds including a new cinnamamide (1), N-(1-cinnamoylpyrrolidin-2-yl)cinnamamide, and two compounds (8 and 9) first isolated from natural sources, were obtained from the edible mushroom Pholiota lubrica. Their structures were determined by the interpretation of spectroscopic data. Compounds 1, 3 and 9 exhibited the inhibitory activity against lettuce, while compounds 2 and 7 promoted the growth of lettuce.     

Determination of oxycodone and hydrocotarnine in cancer patient serum by high-performance liquid chromatography with electrochemical detection.

We developed an HPLC procedure using electrochemical detection for the quantitation of oxycodone and hydrocotarnine in cancer patients serum. An eluent of methanol:acetonitrile:5 mM pH 8 phosphate buffer (2:1:7) was used for the mobile phase. The calibration curve was linear in the range from 10 ng/mL to 100 ng/mL. The recovery of oxycodone and hydrocotarnine was 97.2% and 90.5%, respectively. The relative standard deviations within-runs and between-runs for the assay of oxycodone or hydrocotarnine were less than 4.8%. The method developed here was better than the method reported previously.     

The reactions of ethyl 3,4-dihydro-4-quinazolylacetate and its derivatives with cyclopentanone. An attempt at the synthesis of the 6,8-diazasteroid system VII

The reaction of ethyl 3,4-dihydro-4-quinazolylacetate ( 1a ) with cyclopentanone in the presence of trifluoroacetic acid gave mainly two decomposition products, carbostyril (VIII) and ethyl 2-aminocinnamate (IX). Two compounds which are suggested to have the 6,8-diazasteroid skeleton were also obtained in poor yield. Ethyl 3,4-dihydro-2-p-methoxyphenyl-4-quinazolylacetate (1b), however, gave 2-p-methoxyphenylquinazoline (XII) as a decomposition product and did not condense with cyclopentanone. Furthermore, two ethyl 3,4-dihydroquinazolylacetates substituted at the 2-position with cyclohexyl (1c) and methyl (1d) groups could not be converted to the expected diazasteroid system.