• Restorative Dentistry and Endodontics
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• v.14 no.2
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• pp.49-64
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• 1989

The purpose of this study was to evaluate the effect of several materials on the healing process of apical wound. Sixteen mandibular premolars obtained from 4 healthy dogs were used for this study. Under general anesthesia, the pulpal chamber of each tooth was opened and the pulps were extirpated. The root canals were then instrumented with H-file and irrigated with physiologic saline solution ; the apices were purposely perforated and enlarged with the engine K-reamer. In the experimental groups, apical wounds were filled with one of calcium hydroxide, hydroxylapatite, and tricalcium phosphate materials, mixture of each materials and physiologic saline solution, with a lentulo spiral. In the control group, apical wounds were not filled with any material. All the root canals were filled by the lateral condensation technique with gutta-percha cone and ZOE sealer. The access opening of all the teeth were closed with amalgam. On the 10, 20, 40 and 60th day after experiment, experimental animals were sacrificed. Segments of jaws, each containing one tooth, were fixed in 10% formalin solution and decalcified in Plank-Rychlo solution. The specimens were embedded in paraffin and serially sectioned to an average thickness of $6{\mu}m$. The sections were stained by hematoxylin-eosin and Masson's trichrome stain method and examined under light microscope. The results were as follows : 1. In the experimental groups, the new bone formations were observed in apical wounds. 2. Fourty days later, apical wounds were healed by granulation tissue in the experimental groups, but were not healed by granulation tissue in the control group, and the healing process of experimental groups were more rapid than that of control group. 3. Sixty days later, chronic inflammation disappeared in the experimental groups, and the materials used showed biologic affinity to the periapical tissue. 4. In all the groups, the resorption of cementum appeared on the 10th and 20th day after experiment, and the deposition of cementum appeared on the 40th and 60th day after experiment, especially showing narrowness of apical foramen due to newly formed cementum in calcium hydroxide group. 5. Calcum hydroxide and tricalcium phosphate particles were gradually resolved, but hydroxylapatite particles were not resolved through the experimental period.

• Fibers and Polymers
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• v.6 no.1
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• pp.28-34
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• 2005

The purpose of the research was to examine the effect of three different levels of enzyme treatment on the physical characteristics and the end-use suitability of the lyocell fabrics made with four different types of commercial wood pulp. The appropriate enzyme concentration for obtaining an optimum as well as consistent physical characteristics and fabric hand trait was 3 g/l for the concentration levels tested in the present investigation. Weight loss was more affected by higher enzyme con­centration than other physical properties. H2 was least affected by enzyme treatment for all three physical properties and fab­ric hand. 5 g/l concentration exhibited little difference from 3 g/l in the physical characteristics, whereas the KES-FB values indicated a significant loss of fabric hand in most PHV s with the 5 g/l concentration level. Among different garment parame­ters, all four fabric types were relatively inappropriate for the men's slacks (MS) fabric due to the lower hand value of koshi required by the MS parameter. However, despite the relatively low koshi values, high fukurami values required for men's dress shirt (MWDS) resulted in the highest THV among the four garment parmeters. The four fabric types, which represent the usage of four different wood pulps, in general seem to exhibit a higher applicability to women's winter thin dress (WWTD) than women's winter suit (WWS) garment parameter.

• Journal of the korean academy of Pediatric Dentistry
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• v.2 no.1
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• pp.67-75
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• 1975

The conserative treatment of the necrotic and infected primary molars is often necessary in order to avoid extractions which may lead to inability to masticate or loss of space and subsequent problems concerning the development of the occlusion in the permanent dentition. The purpose of this study was to evaluate the clinical significance of the conservative treatment of the infected primary molars with necrotic pulps employing the formocresol pulpotomy technique same as in vital teeth and surgical intervention in the cases with a parulis, fistula or cellulitis. The materials consisted of 25 primary molars of 9 boys and 4 girls ranging in age from 4 to 7 years. This study included clinical and radiographic observation at 3-month intervals postoperatively. The following results were obtained. 1. Clinically, 20 cases of 25 were successful, exhibiting no clinical problems such as fistula, mobility, toothache and tenderness to percussion, etc. 5 cases were regarded as failures. 2. Radiographiclly, 14 cases revealed normal features, in 6 cases slight rarefaction was observed in the periapical and interradicular region, and marked periapical and interradicular rarefaction was observed in 5 cases. 3. Marked bony deposition was observed in the periapical and interradicular regions in all the remainder except for 5 failurese. 4. Pathologic root resorption was observed in 2 cases. 5. No alveolodental ankylosis was observed. 6. Regeneration of the dental sac of the permanent tooth was observed in 1 case of 2 cases which had revealed loss of the dental sac.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.153-164
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• 1990

Human dental pulps obtained from normal teeth, hypersensitive teeth and teeth with inflamed pulp were studied to measure and to compare the endogenous levels of arachidonic acid metabolites in order to see the relative activities of the different pathways involved in arachidonic acid metabolism. Pulp homogenates were incubated with $^{14}C$-arachidonic acid and lipid solvent extracts were separated by thin layer chromatography (TLC) to be analyzed by autoradiography and TLC analyzer. 1. The most significant metabolite was HETEs showing $96.9{\pm}37.8$pmol/mg tissue protein/hr in normal pulp, $169.2{\pm}76.7$ in hypersensitive pulp and $385.4{\pm}113.2$ in inflamed pulp. In normal pulp $LTB_4$, 6-keto-$PGF_{1\alpha}+PGE_2$, $TXB_2$ and unidentified metabolite were formed in decreasing order. While in hypersensitive and inflamed pulp 6-keto-$PGF_{1\alpha}+PGE_2$, $LTB_4$, $TXB_2$ and unidentified metabolite were formed in decreasing order. 2. In hypersensitive pulp only HETEs were significantly increased when compared with that in normal pulp. The levels of all the converted metabolites in inflamed pulp were significantly increased compared with those in normal pulp. In inflamed pulp, the levels of $TXB_2$ and HETEs were significantly increased compared with those in hypersensitive pulp. 3. The ratio of each metabolites to the total converted metabolites showed an increased value of $TXB_2$ and 6-keto-$PGF_{1\alpha}+PGE_2$, as the degree of inflammation was increased, while that of HETEs decreased both in hypersensitive pulp and inflamed pulp more than in normal pulp. 4. The relative amounts of the total metabolites formed in lipoxygenase pathway to cyclo-oxygenase pathway were 6.8 fold in normal pulp, 4.4 fold in hypersensitive pulp and 3.8 fold in inflamed pulp.

• Restorative Dentistry and Endodontics
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• v.38 no.4
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• pp.210-214
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• 2013

Objectives: This study aimed to evaluate the capacity of 2% chlorhexidine gel associated with 8% papain gel in comparison with 5.25% sodium hypochlorite in bovine pulp tissue dissolution. Materials and Methods: Ninety bovine pulps of standardized sizes were used and fragmented into 5-mm sizes. The fragments were removed from the root middle third region. They were divided into 6 experimental groups (n = 15), 1) 8% papain; 2) 2% chlorhexidine; 3) 2% chlorhexidine associated with 8% papain; 4) 0.9% saline solution; 5) 2.5% sodium hypochlorite; and 6) 5.25% sodium hypochlorite. The pulp fragments were weighed and put into immobile test tubes for dissolution for time intervals of 30, 60, 90, and 120 min. Results: The 5.25% sodium hypochlorite had greater dissolution potential than the pure papain, and when associated with chlorhexidine, both promoted greater dissolution than did the saline solution and 2% chlorhexidine groups (p < 0.05). The 2.5% sodium hypochlorite promoted dissolution to a lesser extent than the groups with papain within a period of 30 min (p < 0.05), but, was comparable to the saline solution and chlorhexidine. After 120 min, the 2.5% and 5.25% sodium hypochlorite promoted dissolution of 100% of the pulp fragments, and papain, 61%, while chlorhexidine associated with papain and chlorhexidine alone dissolved only 55% and 3%, respectively. Conclusions: The 8% papain in gel, both alone and in association with chlorhexidine, was able to dissolve bovine pulp tissue, but to a lesser extent than did 5.25% sodium hypochlorite.

• Journal of Plant Biology
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• v.1 no.1
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• pp.27-37
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• 1958

Durlng various experiments and investigations with antigrowth virus, I studied especially the infective and antiinfective process of it in small animals, and have got following results: 1. The rabbits are easily infected with this virus, having following five stages; incubation period of 2 to 3 days, stage of fever for 2 to 4 day, transient anemic stage, transient fcteric stage and stage of lasting iron-precipitation in the spleen. 2. According to the appearance of icteruis, I have divided the rabbits into following three groups, the first gorup, weighting less than 1000g, died after appearance of icterus, the second group, weighting 1000 to 1500 g. recoy ered after appearance of icterus, and the third group, weighting more than 1500 g. recovered without the appearance of jaundice. 3. In hematological study, marked decrease in R. B. C. and Hb were recognized but various leucocytes except lymphocytes slightly increased. 4. In pathological study, the spleen exhibited marked swelling with abundent blood and indistinct border between trabeculae and pulps at the initial stage of icterus and notable atrophy at the end stage of it. There are few iron-cells in the spleen histologically at the initial stage, but they increased in number with granuar appearance at the end stage. In the first group of rabbits above mentionel, the iron-cells increase suddenly with the death of animal and show diffuse precipitation of iron. The liver and indey have defferent aspects in proportion to icterus. If icterus appears, they show markel changes with turbidity and necrosis, but without icterus they present only slight changes. 5. The neutralining antibody is easily proved in the immunized rabbits for about one year. 6. The passive immunity has the defense immunability until 10\ulcorner 7. Gunia pigs are easily infected with this virus and get the immunity. On fowls this virus can be kept in the blood for about ten days by various inoculating methods, and the fowls obtain the defensive ability by reinoculation, but are unable to succeed this ability from generation to generation. 8. when young swine are infected with this virus, their growth are disturbed and result in atrophied swine. It is therofor presumed that the etiology of the antigrowth of these atrophied swine is similar morphological and functional changes observed in the above rabbits.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.169-179
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• 1994

The purpose of this study was to compare and evaluate the bleaching efficacy of three nonvital bleaching techniques: Walking bleaching, Walking bleaching and heat application, and Walking bleaching and bleaching light application. 36 extracted anterior teeth with intact crowns were immersed in 5 % sodium hypochlorite solution for twenty-four hours to loosen extrinsic debris. Lingual access openings were prepared in all teeth and the pulps were extirpated. The teeth were stored in 5% sodium hypochlorite for twenty-four hours to open the dentinal tubules and they were stained via whole blood. Once the teeth were stained, they were evaluated with Colorimeter. The teeth in each group were ranked from lightest to darkest and divided equally into three experimental groups in which the following bleaching techniques were used. Intracoronal base was placed 2mm below cementoenamel junction. Group 1 Walking bleaching (Superoxol + Sodium perborate) Group 2 Heat application + Walking bleaching (Superoxol+Sodium perborate) Group 3 Light application+Walking bleaching (Superoxol+Sodium perborate) The bleaching agents were changed every 3 days and the teeth were bleached for a total of 14 days. The teeth were evaluated with Colorimeter before the start of any bleaching and on day 14. The results were as follows: 1. At the end of 14 days, all the sample teeth demonstrated the increase of Lightness Index at cervical 1/3 of crown (p<0.05) Lightness Index was significant difference in group 2 and 3, but there were some minor differences among groups (p>0.05). 2. In all groups, there was significant difference in red chromacity (p<0.05), but there were some minor differences among groups (p>0.05). 3. In all groups, there was no significant difference in yellow chromacity (p>0.05).

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.4
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• pp.8-16
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• 2003

The objective of this study was to investigate the potential application of the separated refining system in the papermaking process using cotton pulps. The cotton staple and linter fibers were expected to show a great difference in their refining responses due to their morphological and physical differences. Experiments were conducted to examine the differences in flocculation tendency, CED viscosity, fiber length, handsheet properties and the SEM surface images between staple and linter fibers at a given refining degree. These fibers were also subjected to separated refining in a laboratory-scale beater and in a mill-scale refiner as well. The effect of the separated refining on the refining rates and papermaking properties were evaluated. Results obtained are summarized as follows: 1. Fiber flocculation tendency of cotton staple was estimated to be significantly greater than that of linter fibers; 2. The staple fibers showed higher cellulose DP, longer fiber length and higher sheet strength at a given refining degree compared to linter fibers, but remarkably slower refining rate was observed; 3. The separated refining system exhibited a significant increase in sheet strengths, especiauy in folding endurance, with an increase in the fibrillation on the surface of staple fibers, but slightly lower or comparable fiber length after refining to the mixed refining system; 4. Similar results were also obtained from the machine trial in which about 7-8％ energy saving effects were achived in the separated refining system. On the basis of the results observed in this study, it was concluded that a significant increase in paper strength and a substantial reduction in refining energy consumption could be achieved using the separated refining system for the cotton staple and linter fiber stock refining.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.271-278
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• 2006

We used polymers of alternating cationic and anionic nature to build up shells on fiber surfaces, strengthen the worn-out fibers and improve paper properties made from such fibers. OCC and ONP pulps were either dipped or salted out in the cationic polyallylamine, polyacrylamide and starch solutions. After centrifugal drying, these were followed by treatments in anionic polyacrylic acid, poly-acrylamide, and starch solutions, respectively. The shell-enhanced fibers were formed into handsheets and their physical properties evaluated. The results show that building multiple shells on worn-out fiber surfaces can strengthen the fibers and paper. The simpler and more practical impregnation-centrifuging treatment provided the desired effects, whereas salting out the polymers produced somewhat superior fibers. The latter process, were impractical, however. The first pair of polymeric shells imparted marked strength improvement, whereas later layers had diminishing efficacies. Overall, the methods can improve fiber quality, attaining paper strength requirements without resorting to expensive measures. Alternate cationic polymer and filler powders were also deposited on fiber surface based on the micriparticle system in an anticipation of stiffness gains. Platy minerals, such as montmorillonite, bentonite, sericite, clay and talc were added following cationic PAM. After dewatering of polymer-pigment shelled fiber of one to 3 pairs of layers, handsheets either calendered or uncalendered were evaluated. The results indicate that regardless of calendaring, stiffness of the handsheets did not improve appreciably while certain other strength properties showed gains. We also attempted the novel starch gel filler addition method wherein tapioca starch and filers (PCC, sericite or clay) were mixed at high solids content of 50% and cooked until gelatinized. The filled handsheets were dried under various conditions and then tested for their properties. Improvements in strengths of modified filled paper were observed.

• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.145-162
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• 2019

This study aimed to increase the sugar and ethanol yield from the mengkuang plant biomass through biological and liquid hot water (LHW) pretreatment and their combination. The results showed that biological pretreatments with 5% inoculum of the fungus Trametes versicolor resulted in the highest alpha cellulose content incubated for 30 days, and 10% inoculum resulted in the lowest lignin content. LHW pretreatment decreased the hemicellulose content of pulps from 10.17% to 9.99%. T. versicolor altered the structure of the mengkuang pulp by degrading the lignin and lignocellulose matrix. The resulting delignification and cellulose degradation facilitate the hydrolysis of cellulose into sugars. The alpha cellulose content after biological-LHW pretreatment was higher (78.99%) compared to LHW-biological pretreatment (76.85%). Scanning electron microscopy analysis showed that biological-LHW combinated treatment degrades the cell wall structures. The ethanol yield for biological-LHW pretreated sample was observed 43.86% (13.11 g/L ethanol by weight of the substrate, which is much higher than that of LHW-biological pretreatment (34.02%; 9.097 g/L). The highest reducing sugar content about 45.10% was observed with a resulting ethanol content of 15.5 g/L at LHW pretreatment temperature of $180^{\circ}C$ for 30 min.