Local Structures of Bismuth Ion in Bismuth-Doped Silica Glasses Analyzed Using Bi LIII X-Ray Absorption Fine Structure

Local structures around a bismuth ion in bismuth-doped silica glasses (BiSG) are analyzed using a Bi L_III X-ray absorption fine structure (XAFS). The XAFS spectrum of crystalline α-Bi₂O₃ was also measured for comparison with BiSG whose first peaks are about 0.1 Å less than α-Bi₂O₃ in radial structure functions. According to curve-fitting results using FEFF 8.2, the Bi–O distances of the first and second neighboring coordination spheres are estimated to be 2.1 and 2.3 Å, respectively. The former corresponds to Bi⁵⁺–O bonding and the latter to Bi³⁺–O bonding compared with the Bi–O distances in typical crystals including Bi³⁺ and Bi⁵⁺ ions. The above results show that Bi ions in BiSG exist as both Bi³⁺ and Bi⁵⁺ states, which is also supported by X-ray absorption near the edge structure spectra of BiSG.     

The Introduction of Economic Methods to Scientometrics: The Citing-Cited Table and the Autopoietic Systems of Citations

The paper is introducing an economic method (interindustry relations analysis) into studies of autopoietic systems and shows its application to scientometrics, which can also be regarded as the analysis of autopoietic systems. The merit of the application is discussed, and the outline of the proof of a related theorem is suggested in the appendix.     

Prefabricated free jejunal transfer: a new reconstructive technique for high pharyngeal defects

A new method that uses a prefabricated free jejunal transfer has been applied to three cancer patients with pharyngoesophageal defects with a high pharyngeal deficit extending up to the nasopharynx. In this method, the jejunum harvested in the usual manner is divided into two segments with a single vascular pedicle. Its distal segment is used to reconstruct the cervical esophagus, and its proximal segment is turned over to create a mucosal patch to cover the high pharyngeal defects. The two segments are then co-apted in a side-by-side anastomosis. The esophagus can be reconstructed in a naturally straight shape without a curved portion or blind loop formation, thus leading to good swallowing function. In our series, all grafts survived well and there was no complication directly related to jejunal transfer. All patients could tolerate a soft diet without difficulty. This method is easy to perform and applicable to any shape or size of very high pharyngeal defects that cannot be reconstructed properly by other methods. Although patients with an advanced hypopharyngeal cancer usually have a poor prognosis, this technique allows a better quality of life for a probable short life span.     

Strain-induced crystallization of peroxide-crosslinked natural rubber

Effect of network-chain density (ν) on the strain-induced crystallization of peroxide-crosslinked natural rubber was studied by fast time-resolved synchrotron wide-angle X-ray diffraction. It was observed that the elongation ratio at the onset of strain-induced crystallization (α_c) became smaller with the increase of ν. The difference of the entropy between the undeformed and deformed states at each α_c was nearly equal in spite of the variation of ν. The calculated melting temperature at α_c of the samples was also almost the same regardless of their ν. These observations mean that the strain-induced crystallization occurred when the deformation brought about a definite entropic state for peroxide-crosslinked natural rubber. They agreed with the prediction by Flory and were consistent with the classical theory of rubber elasticity.     

Preparation and properties of fluoroalkyl end-capped oligomer/fluoresceins nanocomposites

Self-assembled fluorinated oligomeric aggregates formed by fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers, N,N-dimethylacrylamide oligomers, and acrylic acid oligomers in methanol could recognize selectively fluoresceins as guest molecules to form a new class of fluorinated aggregates/fluoresceins nanocomposites. These fluorinated fluoresceins nanocomposites were found to exhibit an extraordinarily enhanced light absorption (λ_max: ca. 440 nm) compared to that (λ_maxs: 452 and 480 nm) of the parent fluorescein in the absence of fluorinated aggregates. On the other hand, fluoroalkyl end-capped 2-carboxyethyl acrylate oligomers, which possess no aggregate characteristic in methanol solutions, could not afford such an enhanced light absorption peak under similar conditions. Not only fluorescein but also fluorescein derivatives such fluoresceinamine, carboxyfluorescein, and fluorescein isothiocyanate afforded similar enhanced narrow absorption peaks under similar conditions. Naphthofluorescein was also encapsulated into these fluorinated oligomeric aggregate cores to afford fluorinated aggregates/naphthofluorescein composites, and these fluorinated naphthofluorescein composites afforded an extremely enhanced narrow absorption peak around 520 nm.     

Synthesis of the Optically Active Polymer Consisting of Chiral Phosphorus Atoms and <Emphasis Type="Italic">p</Emphasis>-Phenylene-ethynylene Units

Summary We successfully synthesized optically active polymer 4 by using chiral bisphosphine, (S,S)-1,2-bis(boranato(t-butyl)methylphosphino)ethane (S,S)-1, as a key building block. The structure of the polymer was characterized by ¹H, ¹³C, and ³¹P NMR spectra. According to the CD spectra, the p-phenylene-ethynylene unit in the polymer main chain exhibited Cotton signals around the area of π-π^* transition band.     

Glycosphingolipids with Very Long-Chain Fatty Acids Accumulate in Fibroblasts from Adrenoleukodystrophy Patients

Adrenoleukodystrophy (X-ALD) is an X-linked genetic disorder caused by mutation of the ATP-binding cassette subfamily D member 1 gene, which encodes the peroxisomal membrane protein, adrenoleukodystrophy protein (ALDP). ALDP is associated with the transport of very-long-chain fatty acids (VLCFAs; carbon chain length ≥ 24) into peroxisomes. Defective ALDP leads to the accumulation of saturated VLCFAs in plasma and tissues, which results in damage to myelin and the adrenal glands. Here, we profiled the glycosphingolipid (GSL) species in fibroblasts from X-ALD patients. Quantitative analysis was performed using liquid chromatography–electrospray ionization–tandem mass spectrometry with a chiral column in multiple reaction monitoring (MRM) mode. MRM transitions were designed to scan for precursor ions of long-chain bases to detect GSLs, neutral loss of hexose to detect hexosylceramide (HexCer), and precursor ions of phosphorylcholine to detect sphingomyelin (SM). Our results reveal that levels of C25 and C26-containing HexCer, Hex2Cer, NeuAc-Hex2Cer, NeuAc-HexNAc-Hex2Cer, Hex3Cer, HexNAc-Hex3Cer, and SM were elevated in fibroblasts from X-ALD patients. In conclusion, we precisely quantified SM and various GSLs in fibroblasts from X-ALD patients and determined structural information of the elevated VLCFA-containing GSLs.     

Comparative analysis of a CFo ATP synthase subunit II homologue derived from marine and fresh-water algae

Comparative analysis was performed with a CFo ATP synthase subunit II homologue (CFo-II) derived from marine or fresh-water algae. The marine algae-derived CFo-II-transformed Escherichia coli grew and accumulated ATP more vigorously in NaCl or Cadmium containing medium, suggesting that this gene was useful for the development of stress-tolerant plant.     

Synthesis of cylindrical polyamides from hexakis (4-carboxyphenoxy)cyclotriphosphazene and p-xylyenediamine

Summary The synthesis of cylindrical polyamides by condensation of salts prepared from hexakis(4-carboxyphenoxy)cyclotriphosphazene (2) and diamines was investigated. Among the diamines used, p-xylylenediamine (4) gave the salt (5) composed of 1 : 3 2 – 4. The condensation of 5 at 240 °C for 60 h gave a polyamide (6a) but some carboxyl groups remained without reaction. By adding excess 4 to 5 in a sealed tube, however, polyamide (6b), which showed no significant peak assignable to the carboxyl group in FT-IR and ¹³C-CPMAS spectra, was obtained. X-ray diffraction studies showed that 6a was amorphous but 6b has a high level of crystalline character. From these results and the structural feature of 2, it appears that 6b takes a three-dimensional cylindrical structure. The thermogravimetric analysis of 6b exhibited that the onset temperature of decomposition was 300 °C under both nitrogen and air atmospheres. Received: 29 August 2001/Accepted: 4 October 2001     

Electrochemical detection and control of interactions between DNA and electroactive intercalator using a DNA-alginate complex film modified electrode

The surface of a glassy carbon electrode was modified with a DNA-alginate complex film in which water-soluble DNA was encapsulated into a calcium-alginate gel. The resulting modified electrode (DAFE) was used to detect ethidium bromide (EtBr), after its accumulation on the electrode. The intercalative behavior of EtBr for dsDNA in the film was investigated by measuring the electrode response based on the intercalation of EtBr separated from nonspecific interactions (electrostatic interaction). The accumulation of EtBr in the dsDAF was enhanced by applying a negative potential below -200 mV at the dsDAFE. When a positive potential above +700 mV was applied to the dsDAFE for a constant time with stirring in a Tris buffer solution, the amount accumulated decreased. These results indicate that it is possible to electrochemically control the accumulation and release of EtBr when a dsDAFE is used. In addition, the accumulation and detection of EtBr in spiked river water samples and daunomycin, an antitumor agent, is described.