• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.332-337
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• 2016

Paraformaldehyde has been used in the past as a pulpotomy agent. However, it has a severe cytotoxic effect and may cause alveolar bone necrosis. Depulpin, a devitalizing agent containing 49% paraformaldehyde, is no longer used frequently due to its severe side effects. In the two cases described in the present study, Depulpin was used as a devitalizing agent during root canal treatment. It caused a gradual loss of sensibility in adjacent teeth, gingival necrosis, and osteomyelitis. This case report demonstrates the serious side effects of using a paraformaldehyde-containing paste as a devitalizing agent for pulp, particularly mandibular bone necrosis.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.189-189
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• 1982

This study was carried out to determine the possibility of making fiberboard through the dry forming process, utilizing the tannin-like material of the Asplund pulp from the silk worm oak as a binder. The fiberboard was made through paraformaldehyde treatment, spray of NaOH solution and adjustment of mat moisture content, by hot-pressing at $220^{\circ}C$, and 50-6-50kg/$cm^2$ pressure with 6-min. (0.6-1.8-3.6) three-stage pressing cycle. The results are summarized as follows: 1. The modulus of rupture value of fiberboard treated with NaOH solution was greater than that of untreated. The value was increased in proportion to the paraformaldehyde content from I to 5%, but there was no increasing between 5 and 7% paraformaldehyde content. The value became higher along with the increase of mat moisture content from 15% to 25%. 2. The water adsorption of fiberboard treated with NaOH solution was lower than that of untreated. The value was de"creased in proportion to the paraformaldehyde content from 1 to 5%, but there was no decreasing between 5 and 7% paraformaldehyde content.. 3. A good quality fiberboard (modulus of rupture value of about 250kg/$cm^2$) was made through 5% paraformaidehyde treatment and 3% treatment of 10% NaOH solution, when the mat moisture content was 25%. was 25%.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.151-160
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• 2000

The effect of concentration as factor in cytotoxicity, protein synthesis and alkaline phosphatase activity was compared for pulpotomy medicaments (formaldehyde, formocresol, paraformaldehyde, ferric sulfate) Human pulp fibroblasts were exposed to a range of concentrations(0.01, 0.05, 0.10, 0.25, 0.50, $1.00{\mu}l/ml$) of each agents, for period of 24hrs. The cell activities were evaluated by MTT assay, protein assay and alkaline phosphatase activity examination. The results as follows : 1. After 24hrs culture, pulp fibroblasts adding formaldehyde, formocresol and paraformaldehyde were suppressed cell activities with concentration increasing, but, no depression of cell activities by ferric sulfate. No significant difference was in formaldehyde, formocresol and paraformaldehyde. 2. Protein synthesis by pulpotomy agents were not significant difference in pulp fibroblasts but protein synthesis were a little decreased by paraformaldehyde. 3. Alkaline phosphatase activity was a little decreased by pulpotomy medicaments.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.1
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• pp.41-49
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• 1991

The reaction of molten urea with paraformaldehyde in sealed tubes has been examined, and the concentrations of the products obtained from this reaction have been contrasted to previous results from the identical reaction carried out in open beakers. In these studies, high performance liquid chromatography(HPLC) and nuclear magnetic resonance(NMR) spectroscopy were used to analyze the products formed in the reactions. These products were biuret, triuret, dimethylenetriurea, methylenediurea, and biuretmethyleneurea. The results from the HPLC analyses showed that the concentrations of dimethylenetriurea and methylenediurea in the reaction products increased as the amount of the paraformaldehyde starting material increased. However, the amount of biuret formed in the products decreased as the paraformaldehyde concentration was increased in the urea melt. The results from the NMR analyses showed that the $NH_2$ resonance frequencies for urea, methylenediurea, and dimethylenetriurea all occurred at approximately 5.6 ppm, while the $NH_2$ frequencies for biuret and triuret occurred at approximately 6.9ppm. In the case of biuret and triuret, NH protons absorb between 8.5 and 9.5 ppm, whereas the NH protons in methylenediurea and dimethylenetriurea absorb in the 6.5-6.6ppm region. The melt reaction seems to hold promise as a different technique for ureaform preparation in general.

• Journal of Food Hygiene and Safety
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• v.31 no.3
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• pp.216-221
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• 2016

This study was performed to evaluate the bactericidal efficacy of a fumigation disinfectant containing 35% paraformaldehyde against Salmonella Typhimurium (S. Typhimurium). In this study, the efficacy test of a fumigant against S. Typhimurium was carried out according to French standard NF T 72-281. The S. Typhimurium working culture suspension number (N value), all bacteria numbers on the carriers exposed to the fumigant (n1, n2, and n3), the number of bacterial suspensions by the pour plate method (N1), the number of bacterial suspensions by the filter membrane method (N2), and the mean number of bacteria recovered on the control carriers (T value), were obtained from the preliminary test. In addition, the reduction number of S. Typhimurium exposed to the fumigant (d value) was calculated using the T value, the mean number of bacteria in the recovery solution (n'1) and the mean number of bacteria on carriers plated in agar (n'2). The N value was $5.5{\times}10^8$ colony forming units (CFU)/mL, and n1, n2, and n3 were higher than 0.5N1, 0.5N2 and 0.5N1, respectively. Additionally, the T value was $3.5{\times}10^6CFU/carrier$. In terms of the bactericidal effect of the fumigant, the d value was 5.25. According to the French standard for fumigants, the d value for an effective bactericidal fumigant should be greater than 5. The results indicated that the fumigant containing 35% paraformaldehyde had an efficient bactericidal activity against S. Typhimurium, and, therefore, can be used to disinfect food materials and kitchen appliances contaminated with foodborne bacteria.

• Journal of the Korean Wood Science and Technology
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• v.17 no.4
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• pp.26-34
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• 1989

This study was carried out to manufacture bark board from oak bark by new processes and to examine the physical and mechanical properties of the board. This process with no addition of adhesive used higher pressure and temperature than the conventional one and was applied with or without paraformaldehyde. The results are as follows: 1. The new manufacturing process allowed a good bark board with high absorption coefficient. 2. The best manufacturing process for the mechanical properties of bark board was paraformaldehyde 10%-$250^{\circ}C$-100kg/$cm^2$-3 minutes, (bending strength 40kg/$cm^2$, internal bonding strength 2kg/$cm^2$) and the best manufacturing process for both the mechanical properties of bark board and economic point of view was $250^{\circ}C$-100kg/$cm^2$-3 minutes (bending strength 28kg/$cm^2$, internal bonding strength 1.52kg/$cm^2$). 3. Bark board showed specific gravities from 0.94 to 1.03 and air dried moisture content 9.2% to 11.7%, but Bark board needed paraffin wax emusion treatment. 4. The absorption coefficient of bark boards had two peaks along with frequency; one in 200-400 cps, the other 1200-2000 cps. The former was low but the latter great.

• Bulletin of the Korean Chemical Society
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• v.15 no.8
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• pp.692-694
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• 1994

• Applied Biological Chemistry
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• v.24 no.4
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• pp.238-244
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• 1981

The thin Layer chromatographic determination of ${\alpha}-solanine $ in potato tuber was investigated. The solanine was extracted with methanol-chloroform mixture (2 : 1, v/v) and precipitated as the crude glycoalkaloid by the addition of ammonium hydroxide. The solanine in the crude precipitate was separated by TLC using a solvent system of 1% $NH_4OH-absolute$ ethanol-chloroform (1:2:2, v/v). The purity of ${\alpha}-solanine $ was confirmed by infrared spectrophotometry. The ${\alpha}-solanine $ separated by TLC was determined at the wavelength of 310nm after coloration with concentrated sulfuric acid-1% paraformaldehyde, with the molar absorptivity of 2,090.

• Molecules and Cells
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• v.40 no.1
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• pp.24-36
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• 2017

The stability of peptide-MHC complex (pMHC) is an important factor to shape the fate of peptide-specific T cell immune response, but how it influences on T cell activation process is poorly understood. To better understand that, we investigated various T cell activation events driven by $L^d$ MHCI loaded with graded concentrations of P2Ca and QL9 peptides, respectively, with 2C TCR Tg T cells; the binding strength of P2Ca for $L^d$ is measurably weaker than that of QL9, but either peptides in the context of $L^d$ interact with 2C TCR with a similar strength. When their concentrations required for early T cell activation events, which occur within several minutes to an hour, were concerned, $EC_{50}s$ of QL9 were about 100 folds lower than those of P2Ca, which was expected from their association constants for $L^d$. When $EC_{50}s$ for late activation events, which takes over several hours to occur, were concerned, the differences grew even larger (> 300 folds), suggesting that, due to weak binding, $L^d/P2Ca$ dissociate from each other more easily to lose its antigenicity in a short time. Accordingly, fixation of $L^d/P2Ca$ with paraformaldehyde resulted in a significant improvement in its immunogenicity. These results imply that binding strength of a peptide for a MHC is a critical factor to determine the duration of pMHC-mediated T cell activation and thus the attainment of productive T cell activation. It is also suggested that paraformaldehyde fixation should be an effective tool to ameliorate the immunogenicity of pMHC with a poor stability.

• Journal of the Korean Chemical Society
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• v.24 no.4
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• pp.322-328
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• 1980

1,3,5,7-Tetranitro-1,3,5,7-tetraazacyclooctane (homocyclonite) is prepared simultaneously with 1,3,5-trinitro-1,3,5-triazacyclohexane (cyclonite) by nitrolysis of hexamethylenetetramine. The purpose of our study was to detect the existence of intermediate, 1,5-endomethylene-3,7-dinitro-1,3,5,7-tetraazacyclooctane (DPT), by liquid chromatography based on the reaction mechanism, to derive the theoretical equation which is determinated by the ratio of total methylene group vs. amino N, for the proper quantity of paraformaldehyde added in the reaction and to obtain the optimum condition for maximum yield and purity by comparing the experimental results with the theoretical equation.