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.     

Characteristic distribution of gap junctions in rat lacrimal gland in vivo and reconstruction of a gap junction in an in vitro model

We investigated localization of the gap junction in rat lacrimal gland in vivo and in vitro using electron microscopy and immunostaining with anti-connexin32 (Cx32) monoclonal antibody (HAM8). In immunofluorescence study of lacrimal gland tissues, Cx32 protein appeared to exist not only at the intercellular borders of acinar cells, but also in the basal regions, where there apparently was no contact with adjacent acinar cells. Thin sectioning and immunoelectron microscopy revealed that lacrimal acinar cells formed autocellular gap junctions (reflexive gap junctions) in the basal regions and intercellular gap junctions with adjacent acinar cell membranes. In immunofluorescence study of primary culture, Cx32 protein was found on the free surfaces of isolated acinar cells at the early stage of culture. With culturing time, cell aggregates were formed. We observed Cx32 immunoreactivity between acinar cells in these aggregates, but not on their free surface. Electron microscopic study confirmed that these aggregates possessed intercellular gap junctions and morphologically differentiated acinar-like structures. However, reflexive gap junctions were not observed in these aggregates. In conclusion, lacrimal acinar cells form intercellular and reflexive gap junctions in vivo. On the other hand, the existence of an acinar-like structure and intercellular gap junctions indicates that acinar cells differentiated in vitro morphologically. The cells may communicate with each other through these junctions, organizing themselves into an acinar cell network in an in vitro situation.     

Automated affinity capture-release of biotin-containing conjugates using a lab-on-valve apparatus coupled to UV/visible and electrospray ionization mass spectrometry

We report a new method for automated affinity capture and release of biotin-containing conjugates on immobilized streptavidin using a lab-on-valve (LOV) bead injection apparatus. The apparatus is also coupled to UV/visible and electrospray ionization mass spectrometry (ESI-MS) for monitoring the captured and released biotin-containing conjugates. Dissociation rate constants for release from streptavidin of two chromophore-tagged biotin conjugates were measured by UV/visible spectrometry and the dissociation was simultaneously monitored by ESI-MS. The LOV-ESI-MS instrument was also used for repetitive assays of lysosomal beta-galactosidase in human cell homogenates. Fast analysis in 4.5 min/full cycle and robust operation in 60 repetitive analyses are demonstrated that are promising for transfer of the LOV-ESI-MS technology into clinical practice.     

Transmission electron microscopy on thin film of high density magnetic composite prepared by FIB method

A thin specimen of a high density magnetic composite (HDMC), which is a type of powder magnetic cores was prepared for transmission electron microscopy (TEM) using a focused ion beam (FIB) method. A homogeneous thin film containing an insulator boundary between the constituent Fe powders was obtained successfully. Using this thin film, detailed flow of magnetic flux was visualized by electron holography, and the magnetic flux density was estimated to be 1.73 +/- 0.09 T being consistent with that of a bulk HDMC (1.70 T). Moreover, through Lorentz microscopy, the characteristic magnetization process of HDMC was observed by applying the magnetic field up to approximately 8 kA/m.