• Fibers and Polymers
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• 제5권1호
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• pp.44-51
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• 2004

Three bi-functional reactive dyes such as Bis(vinylsulphone) type, Bis(monochlorotriazine) type and Bis(mononicotinotriazine) type were applied to regular viscose rayon and new regenerated cellulosic fiber ($enVix^ⓡ$) which was prepared from cellulose acetate fiber by the hydrolysis of acetyl groups, and their dyeing properties and fastness properties were compared. enVix exhibited better dyeability and fastness than regular viscose rayon and these results were also explained by the differences in the supramolecular structure of these two fibers.

• Fibers and Polymers
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• 제5권3호
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• pp.219-224
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• 2004

The reactive printing properties of regular viscose rayon and a new regenerated cellulosic fiber (en Vix^{\textregistered}$) which was prepared from cellulose acetate fiber was investigated in a comparative manner. From the results, it was found that en Vix exhibited better printing properties than regular viscose rayon. It showed stable final color yields, irrespective of the amount of thickener, hence reproducibility of printing of en Vix is expected to be excellent. In addition, urea requirements were less for the printings on en Vix than for the corresponding printing on viscose rayon. Therefore, en Vix is also expected to reduce the amount of the urea which causes environmental problems in dyehouse effluent.

• KSBB Journal
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• 제4권2호
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• pp.177-184
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• 1989

In separating mycelia from antibiotic fermentation broths, high permeate flux was obtained by cross-flow filtration using modified regenerated cellulose membrane. The flux was increased most effectively by increasing the flow rate. There existed a critical mycelium density (about 20% PMV) at which the highest flux was observed. In a batchwise concentration of the fermentation broth, the system suffered from a severe fouling problem, which was relieved drastically by applying diafiltration technique, although it increased the permeate volume. A combined concentration/diafiltration process was ideal in keeping relatively high flux together with a high product recovery yield. The best result was obtained by starting diafiltration after concentrating the broth to 20% PMV. By doing so, a 98% product recovery yield was achieved in the shortest time while keeping the permeate volume at a minimum level.

• Archives of Plastic Surgery
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• 제39권4호
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• pp.317-321
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• 2012

Background Many topical hemostatics are widely applied for bleeding control. They can be classified into two categories according to their mechanism of action on the clotting cascade in a biologically active or passive manner. Passive hemostatics include cellulose and gelatin. We performed an experimental study to compare the effect of passive hemostatics in wound healing by applying them to a rectus abdominis muscle defect of white mice. Methods Surgicel is a sterile absorbable knitted fabric prepared by the controlled oxidation of regenerated cellulose. Spongostan is an absorbable hemostatic gelatin sponge. In 30 mice, a $1{\times}1$ cm defect was created on the rectus abdominis muscle and the materials were applied in three ways: control group, cellulose (Surgicel) group, gelatin (Spongostan) group. For the histologic analysis, biopsies were performed at 3 and 28 days. Results After 3 days, the cellulose group showed limited granulation formation with acute inflammatory reactions similar to the control group. At the 28th day, moderate amounts of granulation tissue formation was observed with milder inflammatory reactions than the control group. In the gelatin group, after 3 days, gelatin remnants were observed surrounded by severe inflammatory changes. After 28 days, the same quantity of gelatin remnants could be still observed. Conclusions This study suggests that cellulose is associated with minimal morbidity in wound healing, while the use of gelatin shows severe adverse tissue reactions with delayed wound healing. Consequently, cellulose is better than gelatin when considering wound healing.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제36권5호
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• pp.539-543
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• 2012

Cellulose Electro-Active Paper (EAPap) is attractive as a biomimetic actuator because of its merits: it is lightweight, operates in dry conditions, has a large displacement output, has a low actuation voltage, and has low power consumption. Cellulose is regenerated so as to align its microfibrils, which results in a piezoelectric paper. When chemically bonded and mixed with carbon nanotubes, titanium oxide, zinc oxide, tin oxides, the cellulose EAPap can be used as a hybrid nanocomposite that has versatile properties and that can meet the requirements of many application devices. This paper presents trends in recent research on the cellulose EAPap, mainly on material preparation and its use in devices, including biosensors, chemical sensors, flexible transistors, and actuators. This paper also explains wirelessly driving technology for the cellulose EAPap, which is attractive for use in biomimetic robotics and micro-aerial vehicles.

• Textile Coloration and Finishing
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• 제11권1호
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• pp.48-60
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• 1999

In this paper, a new regenerated celluosic fiber, "Tencel" was treated with cellulase enzyme. Also Tencel fabrics were pretreated with NaOH and dyed with various reactive dyes, and subsequently finished with DMDHEU. $\Delta{E}^*_{ab}$ value was calculated by measuring color difference before and after wet abrasion test to rubbing. The fibrillation propensity was estimated on Tencel by means of weight loss, $\Delta{E}^*_{ab}$ value, and SEM observation. Weight loss of NaOH pretreated Tencel fabric is more lower than that of original fabric. The cellulase treatment decreased tensile strength but improved wet abrasion strength, wrinkle recovery, and bending properties. Tendency of fibrillation for Tencel fabric was reduced by NaOH-pretreatment, dyeing with multifunctional reactive dyes, and afterfinishing by DMDHEU.by DMDHEU.

• Journal of the Korean Society of Clothing and Textiles
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• 제24권7호
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• pp.1081-1087
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• 2000

Gromwell colorants were extracted with methanol and dried. Four fractions were obtained by silica gel adsorption column chromatography using step-wise elution method. Relative ratio of four fraction is 1.00:0.07:0.22:0.30(Fl:F2:F3:F4) and gromwell colorants mainly consist of Fl, F3 and F4. IR analysis shows that each fraction has similar structure. Main component of gromwell extracts is acetyl derivative of naphthoquinone, and the rest are isobutyl derivative and isovaleryl derivative etc., in order. Gromwell colorants exhibit relatively good affinity to protein and polyamide fibers, but low affinity to cellulose and regenerated cellulose fibers.

• Applied Chemistry for Engineering
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• 제16권2호
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• pp.257-261
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• 2005

The microbial cellulose is in a form of three dimensional net structures that consists of 20~50 nm fibrils. It possesses high crystallinity and orientation. It is difficult to synthesize large amount of fibrous carbon nanomaterials by the carbonization process using raw materials such as polyacrylonitrile (PAN), regenerated cellulose (Rayon) and pitch. However, it seems possible thru the application of microbial cellulose as raw material. The application of such cellulose can be further extended to the synthesis of highly oriented graphite fiber. Out of three different cellulose-producing strains, G. xylinus ATCC11142 was chosen as it has the highest productivity (0.066 g dried cellulose/15 mL medium). Tar is often produced during the carbonization of cellulose that limits the formation fibrous structure of the carbonized sample. In order to solve such a problem, pre-studied purification methods of carbon nanotube such as liquid phase oxidation, gas phase oxidation and filtration associated with ultrasonication were applied at the carbonized cellulose. In that case. only by filtration associated with ultrasonication, improved the formation of fiber structure of the carbonized cellulose.

• Textile Coloration and Finishing
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• 제20권3호
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• pp.31-38
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• 2008

Regenerated composite fibers were prepared from solution of styela clava tunics(SC) and poly vinyl alchol(PVA) using N-methylmorpholine-N-oxide(NMMO)/water(87/13)(wt%/wt%) as a solvent by dry jet-wet spinning. Structure and physical properties of regenerated composite fibers were investigated through birefrngence, x-ray diffratograms, tenacity, fibrillation and SEM. Optimal blend ratio of SC/PVA for mechanical properties of composite fibers was 70/30 and total weight was 4wt% concentrations in NMMO/$H_2O$ solvent system. Crystallinity index of composite fibers were decreased as the PVA contents increased. Fibrillation of $10{\sim}20wt%$ PVA blended fibers were occurred less than pure SC fiber. Shape of composite fibers were a circle cross section within 10wt% PVA content. But the cross section of fibers were changed as crushed flat with the PVA contents increased.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제20권2호
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• pp.112-126
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• 1998

In dentistry, bony defects can be formed by cyst, tumor, inflammation, trauma and surgery in maxilla and mandible. If the overlying soft tissue invades and preoccupies the jaw bony defects, regenerated bony tissue same as adjacent bone can not replace whole space of the defects, thus preventing osteogenesis from occurring. Guided bone regeneration(GBR) is based on the prevention of overlying soft tissue from entering the bony defect during the initial healing periods. E-polytetrafluoroethylene(e-PTFE) is one of an effective and widely used barrier membrane for GBR, but it has the disadvantages such as surgical removal and high price. To overcome such disadvantages of e-PTFE, many investigators have proposed various absorbable barrier membranes. Inexpensive oxidized cellulose($Surgicel^{(R)}$) membrane was shown to have potential for use as an absorbable barrier membrane for regenerative procedure and it would not require surgical removal. The purpose of this study is to investigate the absorption periods of oxidized cellulose at the implant site and usefulness as a mechanical barrier, preventing the ingrowth of the overlying soft tissue into the bony defects. Two bony defects were made in each tibia of a dog using drill and one defect covered with oxidized cellulose and the other covered with periosteum directly as control. The experimental animals were sacrificed at 1st-7th, 10th, 14th, 21th, 28th day postoperatively, Inspection of the specimens was done to evaluate gross changes. Specimens were examined histopathologically by hematoxylin-eosin and Masson's trichrome staining under light microscope. The results were as follows : 1. There was no significant differences of inflammatory reaction between the experimental and the control group. 2. The resorption of oxidized cellulose was almost completed within 14th day. 3. Histologically, bone formation in the experimental group was somewhat more than that of the control group at 10th, 14th, 21th and 28th day postoperatively. The bone forming pattern of the experimental group was more regular than that of the control group. 4. There was no evidence of soft tissue invasion into the bony defect in the experimental group. In conclusion, oxidized cellulose membrane might be used as an alternative absorbable barrier membrane to prevent overlying soft tissue invasion into the bony defects.