We analyzed the rearing and fiber spinning behaviors of Rhodinia fugax and compared them with those of other wild silkworms, namely Antheraea pernyi and Antheraea yamamai. The silkworm’s egg weight was about 1/2 that A. pernyi and 1/3 that of A. yamamai. A single cocoon filament was 16 to 27 μm thick. The spinning loop of the cocoon filament measured 6.5 × 1.8 mm. We observed the structure of the microfibrils on the surfaces of degummed cocoon fibers. The silk fibers had FTIR absorption bands at 1639 cm-1 (amide I) and 1512 cm-1 (amide II); these were attributed to the β-sheet structure. On the differential scanning calorimetry curve of the silk fiber, an endothermic peak appeared at about 76 °C. In addition to minor endothermic peak of the silk fibers at 210 °C, broad endothermic peak appeared at 350 °C, which was attributed to thermal decomposition.
A computer simulation experiment was performed to examine the distribution of panel percentage appearances in neatness testing of raw silk. An appearance model was established on the basis of the Poisson distribution. The correspondence between panel percentage appearance in the neatness test and number of appearances in the Poisson distribution was 100% for 0, 95% for 3, 90% for 6, 85% for 9, and so on, and the standard deviation was almost consisted of the actual lot. This sampling model therefore suitably represented the distribution of panel percentage appearances in the neatness test. (E mail: email@example.com)
We examined the characteristics of the Hachioji textile production area in recent years and the status of goods marketed under its regional brand, “Mulberry City Necktie,” in an attempt to understand the future directions of the industry and revitalize this weaving production area. We performed a series of intensive interviews with members of the Hachioji weaving cooperative and with staff of direct management shops and a company. The main results were as follows. Although the Hachioji textile production area has been known for decades as a necktie production area, in recent years this type of production has struggled to survive under the severe conditions resulting from factors such as a weakening production base. The status of regional-brand goods has been very low among major domestic textile production areas, and production of such goods has been decreasing since 2005. We have two proposals for revitalizing the Hachioji textile production area. First, the weaving industry cooperative should endeavor firmly to maintain its traditional technique of necktie production and should act quickly to gain an understanding of consumer needs. Second, the cooperative should find a way of coping more strategically with the problems inherent to the market, and it should especially tap new markets for its brand goods. (E-mail: firstname.lastname@example.org)
Polyester and nylon strings for the koto, a traditional Japanese string instrument, are popular in Japan because of their strength and affordability. However, many players prefer silk strings because of their elongation and tone. We have been attempting to develop highly durable silk strings by using original Japanese silkworm races. Here, we studied the physical properties and durability of silk strings made from the various cocoons. We found significant differences in the physical properties and durability of the strings from different races, including ‘Koishimaru’ and ‘Platinum Boy.’ (E-mail: email@example.com)
To support the survival of local textile production in the Komatsu area, we examined the postwar development of the area and the production strategies of the local weaving industry. We conducted verbal interviews with Komatsu weaving cooperatives and with staff of a representative weaving company. Peak postwar production occurred between 1970 and 1974. From 1975 until now (2009), textile production has been decreasing; in particular, kimono production has been declining and production using synthetic fibers has been slowly increasing. The cooperatives have initiated many activities, such as the Komatsu Fashion Design Contest, to revitalize this textile production area. The production strategy of both the production district and the weaving company has been to maintain small-scale production of a variety of items; nowadays, synthetic fibers are mainly used. We had two points of advice. The first was that textile production needed to change from sovereignty of production to consumer-focused production. The second was that weaving companies needed to try to develop new goods aimed at meeting future consumer demands.
Tussah silk fibroin (TSF) nanofibers from the Antheraea pernyi silkworm were successfully produced by electrospinning from a TSF trifluoroacetic acid (TFA) solution. The optimum concentration for the production of very thin and smooth-surfaced TSF nanofibers ranged from 10 wt% to 12 wt%. The average diameter of TSF nanofibers spun from 10 wt% TSF TFA solutions and prepared by dissolving TSF fibers at 25 °C was 688±178 nm; that at 40 °C was 287±103 nm. The average diameter of TSF nanofibers spun from 12 wt% TSF TFA solutions and prepared by dissolving fibers at 25 °C was 686±185 nm; that at 40°C was 380±102 nm. In both cases the mean diameters of the TSF nanofibers differed significantly (P < 0.01) between the two preparation temperatures. (*: To whom correspondence should be addressed, Tel +81-268-21-5359, E-mail: firstname.lastname@example.org)
We used scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetry (TG) to examine the physical properties of tussah silk fibroin (TSF) nanofibers prepared from the Antheraea pernyi silkworm by using an electrospinning procedure. TSF nanofibers spun from TSF trifluoroacetic acid (TFA) solution possessed an α-helix and random coil conformations and did not take on a β-sheet structure. The TSF nanofibers showed specific FTIR absorption bands at 1199, 1175, 1135, and 1049 cm-1, presumably because of the trace of TFA present in the sample nanofibers at a molecular level. TSF nanofibers showed no clear molecular structural changes upon heat treatment at about 160 °C for 1 h. However, methanol/water vapor annealing crystallized the TSF nanofibers, which clearly changed from randomly coiled conformation to a β-sheet structure. A minor endothermic peak at about 172 °C on the DSC curve of the TSF nanofibers was attributable to removal of TFA from the nanofibers; this peak disappeared after heat treatment at 160 °C for 1 h.
Because it is difficult to control the fineness of thick silk yarn by using conventional contact size detectors for raw silk, we investigated the development of a new contactless sensing system. We developed a system that uses a capacitance sensor to measure the size of thick silk yarn. Good linearity was present between the size and the output voltage of the sensing system. Good repeatability of the system’s output values was obtained when the same yarn sample was measured repeatedly, indicating that the system was useful for controlling the size of thick silk yarn during reeling (E-mail: email@example.com)
We examined the tensile properties of three kinds of transgenic cocoon fibers in which the fibroin contained EGFP or two kinds of spider dragline.derived proteins. The strain and stress values at breaking point and the Young’s modulus of the transgenic fibers containing the spider dragline.derived proteins were significantly higher than those of wild-type, non-transgenic fibers. These results will be useful for designing new transgenic silks with desirable mechanical properties. (*: To whom correspondence should be addressed, E mail: firstname.lastname@example.org)
To control the gelation rate of silk fibroin aqueous solution during the dialysis process, we investigated the effects of pH buffering of the dialysis solution and changes in the concentration of the fibroin aqueous solution. The pH was adjusted with acetate buffer or citric acid . sodium phosphate buffer. The results suggested that control of pH buffering of the dialysis solution and of the protein concentration were important factors in control of the gelation rate of silk fibroin aqueous solution. In addition, the choice of buffer affected the gelation rate. (*: To whom correspondence should be addressed, E mail: email@example.com)
We report a method for dissolving simultaneously both fibroin and sericin from a cocoon by using a pH-adjusted buffered lithium bromide (LiBr) solution. Buffered 9 M LiBr solution at pH 9 was able to dissolve whole cocoon proteins without any breakdown of molecules. The results suggested that it may be possible to separate fibroin and sericin proteins during the dialysis process by using buffered 9 M LiBr solution at pH 5 and 7 to dissolve the whole cocoon proteins. (*: To whom correspondence should be addressed, E-mail: kojikei @affrc.go.jp)
To improve the dyeability of tussah silk, we examined the effect of alkaline pretreatment on the tensile properties of tussah silk. When the sodium hydroxide concentration was below 8 g/l at 30 °C, below 4 g/l at 50 °C, or below 1 g/l at 70 °C, the tensile properties of the tussah silk were almost the same as those of the controls. These parameters therefore appear suitable for brief pretreatment before dyeing. (Tomohiko hananouchi, E-mail: firstname.lastname@example.org)