• 펄프종이기술
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• 제47권4호
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• pp.88-95
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• 2015

The main sources of recovered paper for newsprint are old newsprint (ONP) and old magazine (OMG). Recently, a lot of advertisement flyers are flowing into bales of ONP and portion of OMG is increasing in recovered paper because the consumption level of coated paper increases. In this study, nonionic surfactant and fatty acid were used as the de-inking agent for froth-flotation process of mixed recovered paper to investigate the effect of increased mixing ratio of OMG. De-inking efficiency of nonionic surfactant decreased as the mixing ratio of OMG increased; ink removal efficiency of froth-flotation is poor, however, the reject ratio increases due to ash from OMG. In comparison with nonionic surfactant, the ash from OMG had a little effect on reject ratio and optical properties of fatty acid applied flotation accept. If nonionic surfactant and fatty acid are added to pulper and flotation cell sequentially, excessive ash from OMG may not give an adverse effect on de-inking efficiency of mixed recovered paper.

• 대한소아치과학회지
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• 제23권3호
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• pp.688-696
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• 1996

Garre's osteomyelitis is a unique form of osteomyelitis characterized rediographically by localized thickening of the periosteum and deposition of laminated subperiosteal bone. The most common inciting factor is a mandibular infection in permanent first molar with necrotic pulp. This disease occurs primarily in children and to date in all instances it has occured only in mandible. It usually results in hard swelling over the jaws, producing facial asymmetry with little or no pain. The overlying skin is normal but can occasionally be inflammed mostly when pain is present. Palpation reveals a usually smooth, bone-hard lesion which feel like an inherent part of the mandible. Unlike other forms of osteomyelitis, there is no marked increase in fever, white bloods cell count, sedimentation rate or alkaline phosphatase value. The treatment of Garre's osteomyelitis usually consist of elimination of the sourses of infection, i.e., either extration of an offending infected teeth or root canal therapy. This treatment almost always results in resolution of the Garre's osteomyelitis. Resistant cases have involved secondary surgery, i.e., decortication and sequestrectomy. This report presents three cases of Garre's osteomyelitis resolved by endodontic treatment. Cliniqtl examination revealed swelling on the face with no tenderness. Periapical radiograph showed deep caries lesion extending into pulp chamber and periapical radiolucency. Occlusal radiograph showed an enlargement of bone and stretching the periosteum. A clinical diagnosis of the Garre's osteomyelitis was made. Endodontic treatment was accomplished with conventional method and restored facial symmetry. Long-term check-ups are necessary to evaluate the results of endodontic treatment.

• Journal of Biosystems Engineering
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• 제38권2호
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• pp.113-120
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• 2013

Purpose: Stem cells provide new opportunities in the regenerative medicine for human or animal tissue regeneration. In this study, we report an efficient method for the modulating behaviors of electro-active stem cells by micro-electric current stimulation (mES) without using chemical agents, such as serum or induction chemicals. Methods: Dental pulp stem cells (DPSCs) were cultured on the tissue culture dish in the mES system. To find a suitable mES condition to promote the DPSC functions, the response surface analysis was used. Results: We found that a working micro-current of 38 ${\mu}A$ showed higher DPSC proliferation compared with other working conditions. The mES altered the expressions of intracellular and extracellular proteins compared to those in unstimulated cells. The mES with 38 ${\mu}A$ significantly increased osteogenesis of DPSCs compared with ones without mES. Conclusions: Our findings indicate that mES may induce DPSC proliferation and differentiation, resulting in applying to DPSCs-based human or animal tissue regeneration.

• Restorative Dentistry and Endodontics
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• 제29권6호
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• pp.498-503
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• 2004

The properties of ideal root canal sealers include the ability of sealing the total root canal system and no toxic effects to periradicular tissues. Cytotoxicity test using cell culture is a common screening method for evaluation of the biocompatibility of root canal sealers. The purpose of this study was to investigate the cytotoxic effect of newly developed resin-based sealer (Adseal 1, 2, and 3) comparing with those commercial resin-based sealers (AH26 and AH Plus), ZOE-based sealers (Tubliseal EWT, Pulp Canal Sealer EWT) and calcium hydroxide based sealer (Sealapex), An indirect contact test of cytotoxicity by agar diffusion was performed according to the international standard ISO 10993-5. L929 fibroblast cells were incubated at $37^{\circ}C$ in humidified 5% $CO_2-containing$ air atmosphere. The freshly mixed test materials were inserted into glass rings of internal diameter 5 mm and height 5 mm placed on the agar. After the 24 hrs incubation period, the decolorization zones around the test materials were assessed using an inverted microscope with a calibrated screen. A Decolorization Index was determined for each specimen. Adseal 1. 2, and 3 did not exert any cytotoxic effects, whereas AH26, AH Plus, Tubliseal EWT, Pulp Canal Sealer EWT, and Sealapex produced mild cytotoxicity.

• Toxicological Research
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• 제13권4호
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• pp.401-408
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• 1997

Adult male ICR mice were exposed to methylmercuric chloride (CH$_3$HgCI) through drinking water for 80 days. The distribution of mercury in the kidney, liver, spleen and cerebellum of the mouse was examined according to a autometallographic silver-enhancement technique based on a physical development process which renders mercury deposit visible. Grains of mercury traces were located in the proximal convoluted tubules. Lesser staining of the grains was seen in the collecting tubules of medulla. The glomerular basement membrane was void. In the liver, mercury accumulations were present primarily in the hepatocytes around portal area containing interlobular bile duct, artery and portal vein. Also grains of mercury traces were accumulated in the white pulp of the spleen and Purkinje cell layer of the cerebellum.

• Restorative Dentistry and Endodontics
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• 제27권1호
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• pp.1-11
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• 2002

Immune responses associated with bacterial infection involve various inflammatory cells. Clinical symptoms and pathologic features are particularly influenced by the predominant cells Among inflammatory cells, T cells have the heterogenity. T cells may develop into the mature cells expressing the cell surface markers with different functions and T helper cells are categorized into Th1 and Th2 cells based on their different patterns of cytokine production. The objective of this study was to investigate the change of expression of surface markers on T cells and the Th1/Th2 immune response in pulpal inflammation associated with specific bacteria. We experimentally induced pulpal inflammation in rat incisors by drilling without coolant and innoculated with Streptococcus mutans (S.M. group), Porphyromonas endodontalis (P.E. group), or only sterile cotton (control group). After 1, 2, and 5 days, mandibular incisors were extracted and the pulp tissues were extirpated The expressions of IL-2 recepters (CD25) and ICAM-1 (CD54) on CD4+ and CD8+ cells in the pulps were determined using a flow cytometer, and the concentration of IL-2, IFN-$\gamma$ and IL-4 was measured by enzyme-linked immunosorbent assay. The results were as follows: 1 In the S.M. group, CD4+ cells were more increased at 2nd day than 1st day and in the P.E. group, CD8+ cells were more increased at 2nd day than 1st day. 2. The percentages of CD4+, CD4+25+ and CD4+54+ cells were decreased in the pulp tissues at 5th day after irritation in all groups. 3. The ratios of CD4+/CD8+, CD4+/CD4+25+ and CD4+/CD4+54+ in the pulps at 2nd day after irritation by P. endodontalis were significantly lower than the other groups. 4. The higher concentrations of IFN-$\gamma$ than IL-4 in the pulps at 2nd day after irritation by P. endodontalis showed that T helper 1 reaction were predominant in the early stage of the pulpal inflammation induced by P. endodontalis. 5. The higher concentrations of IL-4 than IFN-$\gamma$ in the pulps at 1st day and 5th day after irritation by S. mutans were measured but the differences were not significant.

• International Journal of Stem Cells
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• 제15권3호
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• pp.301-310
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• 2022

Background and Objectives: RUNX2 plays an essential role during the odontoblast differentiation of dental pulp stem cells (DPSCs). RUNX2 Exon 5 is an alternative exon and essential for RUNX2 transcriptional activity. This study aimed to investigate the regulatory mechanisms of RUNX2 exon 5 alternative splicing in human DPSCs. Methods and Results: The regulatory motifs of RUNX2 exon 5 were analyzed using the online SpliceAid program. The alternative splicing of RUNX2 exon 5 in DPSCs during mineralization-induced differentiation was analyzed by RT-PCR. To explore the effect of splicing factor YBX1 on exon 5 alternative splicing, gaining or losing function of YBX1 was performed by transfection of YBX1 overexpression plasmid or anti-YBX1 siRNA in DPSCs. Human RUNX2 exon 5 is evolutionarily conserved and alternatively spliced in DPSCs. There are three potential YBX1 binding motifs in RUNX2 exon 5. The inclusion of RUNX2 exon 5 and YBX1 expression level increased significantly during mineralization-induced differentiation in DPSCs. Overexpression of YBX1 significantly increased the inclusion of RUNX2 exon 5 in DPSCs. In contrast, silence of YBX1 significantly reduced the inclusion of exon 5 and the corresponding RUNX2 protein expression level. Knockdown of YBX1 reduced the expression of alkaline phosphatase (ALP) and osteocalcin (OC) and the mineralization ability of DPSCs, while overexpression of YBX1 increased the expression of ALP and OC and the mineralization ability of DPSCs. Conclusions: Human RUNX2 exon 5 is conserved evolutionarily and alternatively spliced in DPSCs. Splicing factor YBX1 promotes the inclusion of RUNX2 exon 5 and improves the mineralization ability of DPSCs.

• Preventive Nutrition and Food Science
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• 제9권1호
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• pp.7-13
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• 2004

Lactic acid fermentation of prickly pear extract (PPE) was performed by Lactobacillus rhamnosus LS, Lactobacillus bulgaricus, and Lactobacillus brevis. The PPE was pasteurized to eliminate indigenous microorganisms as well as to dissolve the partially insoluble pulp. The PPE fermented without yeast extract by L. rhamnosus LS exhibited 0.57％ acidity and 3.5${\times}$10$^{8}$ CFU/mL bacteria count. With the addition of 0.2% edible yeast extract the PPE fermented by L. rhamnosus LS exhibited 1.15％ acidity,2.7${\times}$10$^{9}$ CFU/mL bacteria count and 95.0% retention of red color. When 5％ fructose syrup was added, the PPE fermented by L. rhamnosus LS had 1.09% acidity, 6.5${\times}$10$^{8}$ CFU/mL, and 97.7% retention of red color. With 1∼3% (w/v) concentrations of starter, the PPE fermented by L. bulgaricus and L. brevis showed 0.97% and 0.65% acidities, respectively. The viable cell counts from L. rhamnosus LS fermentation were higher compared with those of other LAB. During cold storage at 4$^{\circ}C$, the viable cell count was well maintained for 3 weeks, but then rapidly decreased. The red pigment was highly stable during cold storage for 4 weeks. The pasteurized PPE fortified with 5% fructose syrup, 0.2% yeast extract, and 0.05% CaCO$_3$ was successfully fermented by inoculating with 3% LAB and incubating at 3$0^{\circ}C$ for 2 days. Both viable cell counts and the red color of the fermented PPE were well maintained during cold storage for 3 weeks.

• 대한치과보철학회지
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• 제24권1호
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• pp.125-138
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• 1986

It is considered that etching solution or material itself of phosphoric ester cement will induce not a little pulpal irritation, if applied directly onto unsealed dentinal tubules. This study was designed to confirm above consideration by comparing two different conditions between $Ca(OH)_2$-based and non-$Ca(OH)_2$-based group. Posterior teeth of 15 male dogs were selected for this experiment. One experimental group was filled with cement after $Ca(OH)_2$-basing and enamel-etching, the other experimental group after enamel etching without $Ca(OH)_2$-basing. And both of two experimental groups were observed at 2 hours, 15 hours, 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks after filling. The findings reached to the following conclusions histologically. 1. In both groups, the damaged odontoblasts were atrophied and eventually disappeared. 2. In non-based group at early stage, odontoblasts were severely atrophied and defective areas were appeared between odontoblast cell layers. However, in based group, the odontoblasts were arranged slight irregularly. 3. In non-based group, a small number of undifferentiated cells below the odontoblast cell layers started to appear at 1 week after filling. However, in based group, the undifferentiated cells were appeared at 15 hours after filling. 4. In non-based group, formation of reparative dentin was not begun until late stage of experiment. However, in based group, formation of reparative dentin matrix was begun at 2 weeks after filling and very thickened reparative dentin was formed at 6 weeks after filling. 5. In odontoblast cell layers of both groups, dilated capillaries were observed. 6. Argyrophilic fibers were reticularly condensed in zone of Weil, and they were connected to the pulp tissue and dentin.

• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.261-276
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• 1993

The purpose of this study was to evaluate for the cytotoxicity of glass-ionomer cement liners(GC liningcement, Ketac-bond, Vitrebond and Fuji lining LC) on the fibroblasts cultured from human pulp. The fibroblasts were cultured in DMEM-10% FBS medium. The measurement of pH, succinate dehydrogenase (SDH) activity test and $^{51}Chromium$ release test were performed. Viable cell count and $^{14}C$-leucine incorporation rate were evaluated following culture time of 2, 4 and 6 days. The results of this study were as follows : 1. The pH in all cements was to be neutralized as time elapsed, and Fuji lining LC was the lowest pH value among them. 2. SDH activity was more inhibited in GC lining cement and Vitrebond than Ketac-bond and Fuji lining LC with the setting process, and GC lining cement and Ketac-bond were reduced after 5 minute's setting and then elevated as time elapsed. 3. In SDH activity test following exposure time, the activity in Vitrebond, GC lining cement and Fuji lining LC was inhibited with increased exposure time, but it was fairly constant in Ketac-bond. 4. Overall the liquid component was more inhibited than the powder component of glass-ionomer cement in SDH activity test. 5. In $^{51}Cr$-release test, Fuji lining LC was the most released of all the cements tested and followed by : Vitrebond, Ketac-bond, GC lining cement. 6. In viable cell count, the number of cells increased as the culture day proceeded in Ketac-bond, but they decreased in GC lining cement. Fuji lining LC was only observed after 2 days culture and there was not observed the whole culture days in Vitrebond. 7. In $^{14}C$-leucine incorporation rate test, protein synthesis was decreased with the number of culture days in GC lining cement, Vitrebond and Fuji lining LC, but it was followed that of control in Ketacbond.