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Blood compatibility of regenerated silk fibroin was examined by in vivo blood tests. In vivo tests were made by a method of peripheral vein indwelling suture. The coating of sample fibroin on the polyester suture was made by casting either from aqueous or from formic acid solution. The fibroin-coated sutures from aqueous solution were treated with methanolic aqueous solution in order to denature the silk fibroin, and implanted into a jugular and femoral vein of a dog. The results of the test method employed in this work indicate that the regenerated silk fibroin is nonthrombogenic.

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The states of water sorbed on Merino wool fibers, their histological components, and chemically modified wool fibers were investigated by differential scanning calorimetry (DSC) in order to elucidate the amount of bound water on wool fibers, the differences between the histological components of wool fibers, and the effect of polar groups on the states of water sorbed on wool fibers. For the sake of comparison, the states of water sorbed on cotton and silk were also examined. There may exist three different kinds of water sorbed on wool fibers, i.e., free water, freezing bound water, and nonfreezing bound water. The amount of bound water on wool fibers is larger than that on cotton yam and silk. The amount of bound water on cortical cells is about two times higher than that on cuticular cells. The amount of bound water on nonkeratinous cell components is about three times higher than that on keratinous cell components. The cell membrane complex plays an important role in water penetrating to wool fibers, but its contribution to the amount of bound water is negligible. The contribution of polar groups in wool fibers to the amount of bound water is not specific at high water contents, indicating that the peptide groups of the main chain play a significant role as water binding sites at high water contents.Many of excellent properties of wool as a textile fiber are more or less associated with the specific interactions of wool proteins with water. The ability to bind and absorb large amounts of water is one of the characteristics of wool fibers [ 13]. A relatively large number of .papers have examined the interaction of wool fibers with water using water vapor sorption isotherms [5, 14, 30, 32, 331 and basic calorimetric techniques [4, 20, 26]. Workers have established that part of the water sorbed on natural polymers such as keratin proteins and cellulose and silk fibroin has properties that are markedly different from free water. Many different works have substantiated this consideration [8, 10, 18; 19, 21, 22, 24, 34].On the other hand, wool consists of several histological components that are very different in chemical and physical properties [2,13,36]. It is important to elucidate the differences between these histological components and the functions of individual cell components. Numerous efforts have been devoted to this problem [2,11,12,36]. The accessibility of water molecules to individual histological components of wool has also been studied extensively from various points of view [6,7,23,27,28,29,36], but no study has reported so far on the states of water sorbed on the individual histological components of wool fibers.Recently, Nakamura et al. [22] pointed out that there are three different kinds of sorbed water on polymer: free water, freezing bound water, and nonfreezing bound water, based on the studies using differential scanning calorimetry (DSC). Recent developments in microcalorimetry by DSC enable us to evaluate the contents of free and bound water on polymers [22]. It is of interest to exam...

This work deals with the fibrillation of the cortex of Merino wool by successive freezing (freezing followed by thawing) in various swelling liquids. The freezing- thawing experiments were carried out on native and decuticled wool fibers using water, n-propanol/water, dichloroacetic acid, and formic acid as swelling liquid at freezing temperatures of -78°C and -196°C. The results on native wool showed that the fibers were finely cut in round slices under suitable conditions, but no fi brillation of the cortex occurred under the experimental conditions. For decuticled wool, on the other hand, fibrillation of the cortex was caused by repeating the freezing cycles of 200 in dichloroacetic acid or in formic acid. The orthocortical and paracortical cells were separated from the disintegrated cortex by using a difference in density between both cortical cells, and their amino acid compositions were compared with those reported in literature.

A rapid method for predicting the buckwheat flour ratio of dried buckwheat noodles was developed by using the fluorescence fingerprint and partial least squares regression. Fitting the calibration model to validation datasets showed R(2)=0.78 and SEP=12.4%. The model was refined for a better fit by deleting several samples containing additional ingredients. The best fit was finally obtained (R(2)=0.84 and SEP=10.4%) by deleting the samples containing vinegar, green tea, seaweed, polysaccharide thickener, and yam. This result demonstrates that a calibration model with high accuracy could be constructed based on samples similar in material composition. The developed methodology requires no complex preprocessing, enables rapid measurement with a small sample amount, and would thus be suitable for practical application to the food industry.

The mechanism of bilateral staining of the cortex of wool fibers by basic dyes has been investigated in detail. Merino wool fibers were treated with formic acid and pronase, and their behavior in staining with basic dyes such as methylene blue and janus green was examined using light and electron microscopy. Formic acid is known to remove intercellular cement, one of the nonkeratinous proteins, from the cell membrane complex, while pronase removes all nonkeratinous proteins. Bilateral staining was still distinctly observed after cuticle removal, but not for wool fibers treated with pronase, for fiber fragments obtained by treatment with formic acid with stirring, or for cortical cell particles recovered after fibrillation of the cortex in formic acid. The microfibril-matrix structure of the cortex remained unchanged, however, even after treatment with formic acid and with pronase. These results imply that bilateral staining with basic dyes occurs because of the difference in the network structure of nonkeratinous proteins, especially the intercellular cement of the cell membrane complex between the orthocortex and paracortex.The cortex of fine wool fibers consists of two major segments, the orthocortex and the paracortex, and the bilateral arrangement of these two cortices is closely associated with the crimped structure of wool fibers [2,3,12]. Since its discovery by Horio and Kondo [9] and Mercer [ 18], many researchers have studied the differences in the responses of each component of the bilateral cortex to various dyes and metal ions [2]. These differences have been interpreted in terms of differences in the fine structure or the reactivity between orthocortex and paracortex [2,4,9,10,14,18,19,21 ]. There are several possible differences between the two cortices, however, and their behavior in staining is different with ,dyes and metal ions [2]. The detailed mechanism of bilateral staining of the cortex is still open for discussion to some extent. The pioneer works by Horio et al. [9,10] were done with ionic dyes. The staining mechanism with dyes is relatively simple compared to that with metal ions, which is specific to individual ions. A possible interpretation is that the content of charged groups is different for the orthocortex and paracortex. Wool fibers are composed of a number of ceU components, however, and the accessibility of dye molecules to the charged groups is different for different cell components. There is insufficient experimental evidence to explain why large dye molecules can produce a remarkable contrast in staining between the two cortical components.In a previous paper [ 11 ], we reported on the amino acid composition of the isolated orthocortical and paracortical cells. The results showed that there is little difference in the relative content of the charged groups except for cystine. During the course of this study, we also found that bilateral staining does not occur alter fibrillation of the cortex. These results suggest that the nonkeratinous materials [2,24], which may be remove...

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