Near-infrared spectroscopic analysis of aging degradation in antique washi paper using a deuterium exchange method

The diffusion process of deuterated water (D₂O) in washi (Japanese traditional paper) was investigated by means of a deuterium exchange method and Fourier-transform near-infrared (FT-NIR) transmission spectroscopy. The samples were the modern (AD 2003) hand-made washi and those from an archival collection of cultural artifacts (AD 1791 and 1615). Four absorption bands were identified in the NIR spectral range from 7200 to 6000 cm⁻¹ which are due to OH groups in the amorphous, semi-crystalline and two types of crystalline regions of cellulose. The accessibility of D₂O increased with decreasing state of order of cellulose, and the saturation accessibility increased with the age of the samples. It was suggested that during aging hemicellulose, which forms a composite with cellulose in paper, was progressively hydrolyzed, resulting in the expansion of inter-molecular distance between cellulose chains. The oldest sample showed a low diffusion rate compared with the others. SEM observation of the textile structures indicated that the oldest sample had two layers due to beating. It was estimated that the tight surface layer blocked the diffusant in the initial stage of the diffusion process.     

PHOTODYNAMIC ACTIVITIES and SKIN PHOTOSENSITIVITY OF THE bis(DIMETHYLTHEXYLSILOXY)SILICON 2,3-NAPHTHALOCYANINE IN MICE

The photodynamic therapy (PDT) activity of the bis(dimethylthexylsiloxy)silicon 2,3-na-phthalocyanine (SiNc 8 ) was evaluated against the EMT-6 tumor implanted intradermally in BALB/c mice. The SiNc 8 was formulated in aqueous emulsions based on Cremophor EL or Solutol HS 15. The formulation was shown to affect plasma clearance and overall pharmacokinetics. Compared to Cremophor, Solutol promoted rapid plasma clearance and high liver retention of the dye, combined with a slight increase of dye tumor concentrations. The PDT action spectrum for tumor response of SiNc 8 in Cremophor (190 mW cm², 200 J cm², 24 h postinjection [p.i.] of 1 (jimol kg¹) showed a maximum at 780 nm, which corresponds to the absorption maximum of the monomelic dye as well as the in vivo maximum change in the “diffuse optical density” produced by the dye. The extent of tumor necrosis increased with augmented dye and light doses. Regardless of the formulation, at 1 h p.i. of 0.1 μmol kg^?! SiNc 8 , PDT efficiency (190 mW cm'², 400 J cm²) was high but accompanied by severe damage to normal tissues, at 24 h PDT resulted in complete tumor regression in 80% of the animals without adverse effects to adjacent tissues, while at 72 h p.i. PDT induced no tumor response with Cremophor and only a partial response with Solutol. At the latter time point, plasma dye clearance was nearly complete while tumor tissue levels remained high, suggesting that tumor response correlates with plasma rather than tumor dye levels. Skin sensitivity of SKhl mice to solar-simulated radiation was lower with SiNc 8 as compared to Photofrin®. Our data suggest the potential of SiNc 8 as a far-red absorbing photosensitizer in clinical PDT.     

Flow injection spectrophotometric determination of isoproterenol using an avocado (Persea americana) crude extract immobilized on controlled-pore silica reactor

An enzymatic reactor was constructed by the immobilization of polyphenol oxidase (PPO) from avocado (Persea americana) crude extract in an inorganic support of controlled pore silica (CPS), after a previous step of silanization. This inorganic support has been used as an excellent carrier to immobilize this enzyme and the enzymatic reactor was used in a flow injection system for the determination of isoproterenol in pharmaceutical products. The procedure is based on the oxidation reaction of this drug with immobilized PPO and the product obtained was monitored at 492 nm. This system presented an analytical curve from 1.23x10(-4) to 7.38x10(-4) mol l(-1) isoproterenol with a detection limit of 6.25x10(-5) mol l(-1). Recoveries of isoproterenol between 98.5 and 103.1%, a relative standard deviation (R.S.D.) less than 1% (n=10) and 36 determinations per h were obtained.     

A family of 2-weight codes related to BCH-codes

For every prime-power q and every pair of natural numbers m ≤ n′, we construct a q-ary linear code of length q^m (q^n′ − 1)(q^n′ − q^n′−m + 1)/(q − 1) and dimension 3n′, whose only nonzero weights are and . These code parameters and those of the corresponding family of strongly regular graphs are new in odd characteristic. © 1997 John Wiley & Sons, Inc. J Combin Designs 5: 391–396, 1997     

Ultrafast Internal Conversion in a Model Anthocyanin–Polyphenol Complex: Implications for the Biological Role of Anthocyanins in Vegetative Tissues of Plants

The red flavylium cations of anthocyanins form ground‐state charge‐transfer complexes with several naturally occurring electron‐donor copigments, such as hydroxylated flavones and hydroxycinnamic or benzoic acids. Excitation of the 7‐methoxy‐4‐methyl‐flavylium–protocatechuic acid complex results in ultrafast (240 fs) internal conversion to the ground state of the complex by way of a low‐lying charge‐transfer state. Thus, both uncomplexed anthocyanins, whose excited state decays by fast (5–20 ps) excited‐state proton transfer, and anthocyanin–copigment complexes have highly efficient mechanisms of deactivation that are consistent with the proposed protective role of anthocyanins against excess solar radiation in the vegetative tissues of plants.     

Palythine–threonine,a major novel mycosporine-like amino acid (MAA) isolated from the hermatypic coral Pocillopora capitata

Using a high-resolution reverse-phase liquid chromatography method we found that the tissues of the hermatypic coral Pocillopora capitata (collected in Santiago Bay, Mexico) contain a high diversity of primary and secondary mycosporine-like amino acids (MAAs) typical of some reef-building coral species: mycosporine–glycine, shinorine, porphyra-334, mycosporine–methylamine–serine, mycosporine–methylamine–threonine, palythine–serine, palythine and one additional novel predominant MAA, with an absorbance maximum of 320 nm. Here we document the isolation and characterization of this novel MAA from the coral P. capitata. Using low multi-stage mass analyses of deuterated and non deuterated compounds, high-resolution mass analyses (Time of Flight, TOF) and other techniques, this novel compound was characterized as palythine–threonine. Palythine–threonine was also present in high concentrations in the corals Pocillopora eydouxi and Stylophora pistillata indicating a wider distribution of this MAA among reef-building corals. From structural considerations we suggest that palythine–threonine is formed by decarboxylation of porphyra-334 followed by demethylation of mycosporine–methylamine–threonine.     

Projective Planes, Coverings and a Network Problem

A problem concerning packet switched networks leads to a natural combinatorial design problem, whose solution involves (k, n)-arcs in projective planes, 3-dimensional linear codes, the theory of fractional matchings and designs which approximate projective planes.     

The Largest Cap in AG(4, 4) and Its Uniqueness

We show that 40 is the maximum number of points of a cap in AG(4, 4). Up to semi-linear transformations there is only one such 40-cap. Its group of automorphisms is a semidirect product of an elementary abelian group of order 16 and the alternating group A ₅.