• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1503-1508
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• 2005

The purpose of the present study was to evaluate the effect of Squalene, Alkoxy Glycerol, Batyl and Chimyl solutions on the production of nitric oxide (NO), tumor necrosis factor-alpha (TNF- $\alpha$ ) and interleukin-6 (IL-6) in RAW 264.7 macrophage cells after treatment of C.albicans. The cytotoxic effects was evaluated by the lactate dehydrogenase (LDH). All solutions did not affect on the LDH and NO production by itself. At 6th hour, the TNF- $\alpha$ and IL-6 production was not affected by each solutions. However, at 24th hour, the TNF- $\alpha$ and IL-6 production was affected by itself (p < 0.05). Each solution in the presence of C. albicans decreased the C. albicans-induced TNF- $\alpha$ and IL-6 production compared with C. albicans only (p < 0.05, p < 0.01). These results suggest that Squalene, Alkoxy Glycerol, Batyl and Chimyl solutions will increase the immune response on the C. albicans-induced damage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.3
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• pp.169-175
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• 1976

A solvent extraction-atomic absorption spectrophotometry for determination of trace amount of cadmium, copper, lead and zinc and a flameless atomic absorption spectrophotometry for mercury in sea water were studied. The optimum pH range for solvent extraction was pH 4-7. A better solvent extraction efficiency was obtained with MIBK solvent than nitrobenzene, benzene, isoamylalcohol, n-buthylacetate. DDTC was more advantageous than APDC as chelating agent. The metals, chelated with DDTC and concentrated into MIBK by solvent extraction with a volume of $1\iota$ of sea water for cadmium, copper and lead, and 200m1 for zinc, were determined simultaneously by atomic absorption spectrophotometry. For mercury determination, 500ml of sea water was digested with permanganate-sulfuric acid and mercury( II ) was reduced by stannous chloride and aerated the solution with air pump until the absorbance reached a constant value. The precisions, in standard deviation, of these methods were 0.058ppb for cadmium, 0.084 ppb for copper, 0.44ppb for lead, 2.49ppb for zinc and 0.08 ppb for mercury. The sensitivities, expressed in $ppb/1\%$ absorption, were 0.058 ppb cadmium, 0. 15 ppb copper, 0.6 ppb lead, 1.2 ppb zinc and 0.01 ppb mercury respectively. No significant adsorption on the wall of polyethylene sample bottle occurred during 30 days of storing by acidification to pH 1.5 with nitric acid except zinc. Poor reproducibility was found for zinc with this method.

• Analytical Science and Technology
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• v.13 no.4
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• pp.446-452
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• 2000

The simulated nuclear spent fuel (SIMFUEL) containing the platinum group elements which will not be dissolved in a nitric acid was completely dissolved with a acid digestion bomb. The metallic elements separated in the SIMFUEL were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). Because the peaks of metallic elements were spectrally interfered by uranium spectrum, uranium and metallic elements were separated by cation exchange resin for Mo, Pd, Rh and Ru and by anion exchange resin for Ba, Ce, La, Nd, Rh, Sr, Y and Zr, respectively. The recovery of Mo, Pd, Rh and Ru after separation by cation exchange chromatography found to be 99-103% and anion exchange separation showed 96.5-107% of recovery except Y with the simulated solution whose concentration was similar to the spent nuclear fuel. The relative standard deviation of this method showed 1.3-6.7% in the SIMFUEL whose concentrations of metallic elements were between several $10^2-10^3$ppm.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.780-788
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• 1995

The purpose of this study was to compare the apical seal following root canal shaping by different methods. From fourty extracted mandibular 1st and 2nd molars, fourty mesial roots whose canals have some degree of curvature were selected. The mesiobuccal root portion including mesiobuccal portion of a crown was sectioned in each molar. After access cavity preparation for the mesiobuccal canal, working length was determined with # 10 K-file. The sectioned roots were implanted in acrylic resin block and randomly divided into four groups. The canals of group I were shaped by step-down/balanced force, group II by stepdown/step-back, group III by step-back and group IV by conventional method. All of the shaped canals were obturated by Thermafil method and access cavities were filled with IRM. The roots were removed from acrylic resin block and placed in 100 % humidity for 7days. Except the root surfaces of apical 2mm, the root surfaces were nail-varnished 3 times. After the roots were placed in 700 torr vacuum pressure for 15 minutes, they were immersed in 2% methylene blue solution for 4 days. Nail varnishes were removed with acetone. After that, the roots were decalcified in 5 % nitric acid and dehydrated with alcohol series. Transparent specimens were made by methyl salicylate and the quality of apical seal was assessed by measuring the leakage linearly. The results were as follows. 1. The leakage in canals shaped by step-down/balanced force method was significantly less than that in canals shaped by step-back method(P<0.05) and was less but not statistically than that in canals shaped by step-down/step-back method (P>0.05). 2. The leakage in canals shaped by step-down/step-back method was less than that in canals shaped by step-back method, but there was no statistical significance(P>0.05). 3. The leakage in canals shaped by conventional method was significantly more than that in canals shaped by step-down/balanced force, step-down/step-back and step-back method (P<0.05).

• Clean Technology
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• v.29 no.1
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• pp.46-52
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• 2023

Oxalic acid has been traditionally obtained via the oxidation of carbohydrates using nitric acid and catalysts. However, this process produces a variety of nitrogen oxides during oxidation and requires a separation process due to its various intermediates. These products and additional steps increase the harmfulness and complexity of the process. Recently, the electrochemical reduction of carbon dioxide into oxalic acid has been suggested as an environmentally friendly and efficient technology for the production of oxalic acid. In this electrochemical conversion system, zinc oxalate (ZnC₂O₄) is obtained by the reaction of Zn²⁺ ions produced by Zn oxidation and oxalate ions produced by CO₂ reduction. ZnC₂O₄ can then be converted to form oxalic acid, but this requires the use of a strong acid and heat. In this study, a system was proposed that can easily convert ZnC₂O₄ to oxalic acid without the use of a strong acid while also allowing for easy separation. In addition, this proposed system can also further convert the products into glycolic acid which is a high-value-added chemical. ZnC₂O₄ was effectively separated into Zn(OH)₂ powder and oxalate solution through a chemical treatment and a vacuum filtration process. Then the Zn(OH)₂ and oxalate were electrochemically converted to zinc and glycolic acid, respectively.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.166-179
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• 1999

Apical sealing is essential for the success of surgical endodontic treatment. Root-end cavity is apt to be contaminated with moisture or blood, and is not always easy to be dried completely. The purpose of this study was to evaluate the influence of dry methods of retrocavity on the apical seal in endodontic surgery. Apical seal was investigated through the evaluation of apical leakage and adaptation of filling material over the cavity wall. To investigate the influence of various dry methods on the apical leakage, 125 palatal roots of extracted human maxillary molar teeth were used. The clinical crown of each tooth was removed at 10 mm from the root apex using a slow-speed diamond saw and water spray. Root canals of the all the specimens were prepared with step-back technique and filled with gutta-percha by lateral condensation method. After removing of the coronal 2 mm of filling material, the access cavities were closed with Cavit$^{(R)}$. Two coats of nail polish were applied to the external surface of each root. Apical three millimeters of each root was resected perpendicular to the long axis of the root with a diamond saw. Class I retrograde cavities were prepared with ultrasonic instruments. Retrocavities were washed with physiologic saline solution and dried with various methods or contaminated with human blood. Retrocavities were filled either with IRM, Super EBA or composite resin. All the specimens were immersed in 2% methylene blue solution for 7 days in an incubator at $37^{\circ}C$. The teeth were dissolved in 14 ml of 35% nitric acid solution and the dye present within the root canal system was returned to solution. The leakage of dye was quantitatively measured via spectrophotometric method. The obtained data were analysed statistically using one-way ANOVA and Duncan's Multiple Range Test. To evaluate the influence of various dry methods on the adaptation of filling material over the cavity wall, 12 palatal roots of extracted human maxillary molar teeth were used. After all the roots were prepared and filled, and retrograde cavities were made and filled as above, roots were sectioned longitudinally. Filling-dentin interface of cut surfaces were examined by scanning electron microscope. The results were as follows: 1. Cavities dried with paper point or compressed air showed less leakage than those dried with cotton pellet in Super EBA filled cavity (p<0.05). However, there was no difference between paper point- and compressed air-dried cavities. 2. When cavities were dried with compressed air, dentin-bonded composite resin-filled cavities showed less apical leakage than IRM- or Super EBA-filled ones (p<0.05). 3. Regardless of the filling material, cavities contaminated with human blood showed significantly more apical leakage than those dried with compressed air after saline irrigation (p<0.05). 4. Outer half of the cavity showed larger dentin-filling interface gap than inner half did when cavities were filled with IRM or Super EBA. 5. In all the filling material groups, cavities contaminated with blood or dried with cotton pellets only showed larger defects at the base of the cavity than ones dried with paper points or compressed air.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.1 no.1
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• pp.11-23
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• 2003

A study on the electrolytic dissolution of SUS-304 and Inconel-600 specimen was carried out in neutral salt electrolyte to evaluate the applicability of electrochemical decontamination process for recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds generated by dismantling a retired uranium conversion plant in Korea. Although the best electrolytic dissolution performance for the specimens was observed in a Na2s04 electrolyte, a NaNO$_3$ neutral salt electrolyte, in which about 30% for SUS-304 and the same for Inconel-600 in the weight loss was shown in comparison with that in a Na$_2$SO$_4$ solution, was selected as an electrolyte for the electrochemical decontamination of metallic wastes with the consideration on the surface of system components contacted with nitric acid and the compatibility with lagoon wastes generated during the facility operation. The effects of current density, electrolytic dissolution time, and concentration of NaNO$_3$ on the electrolytic dissolution of the specimens were investigated. On the basis of the results obtained through the basic inactive experiments, electrochemical decontamination tests using the specimens contaminated with uranium compounds such as UO$_2$, AUC (ammonium uranyl carbonate) and ADU (ammonium diuranate) taken from an uranium conversion facility were performed in 1M NaNO$_3$ solution with the current density or In mA/$\textrm{cm}^2$. it was verified that the electrochemical decontamination of the metallic wastes contaminated uranium compounds was quite successful in a NaNO$_3$ neutral salt electrolyte by reducing $\alpha$ and $\beta$ radioactivities below the level of self disposal within 10 minutes regardless of the type of contaminants and the degree of contamination.

• Tuberculosis and Respiratory Diseases
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• v.41 no.3
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• pp.231-238
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• 1994

Backgroud: Since the demonstration of the fact that vascular relaxation by acetylcholine(Ach) results from the release of relaxing factor from the endothelium, the identity and physiology of this endothelium-derived relaxing factor(EDRF) has been the target for many researches. EDRF has been identified as nitric oxide(NO). With the recent evidences that EDRF is an important mediator of vascular tone, there have been increasing interests in defining the role of the EDRF as a potential mediator of hypoxic pulmonary vasoconstriction. But the role of EDRF in modulating the pulmonary circulation is not compeletely clarified. To investigate the endothelium-dependent pulmonary vasodilation and the role of EDRF during hypoxic pulmonary vasoconstriction, we studied the effects of $N^G$-monomethyl-L-arginine(L-NMMA) and L-arginine on the precontracted pulmonary arterial rings of the rat in normoxia and hypoxia. Mothods: The pulmonary arteries of male Sprague Dawley(300~350g) were dissected free of surrounding tissue, and cut into rings. Rings were mounted over fine rigid wires, in organ chambers filled with 20ml of Krebs solution bubbled with 95 percent oxygen and 5 percent carbon dioxide and maintained at $37^{\circ}C$. Changes in isometric tension were recorded with a force transducer(FT.03 Grass, Quincy, USA) Results: 1) Precontraction of rat pulmonry artery with intact endothelium by phenylephrine(PE, $10^{-6}M$) was relaxed completely by acetylcholine(Ach, $10^{-9}-10^{-5}M$) and sodium nitroprusside(SN, $10^{-9}-10^{-5}M$), but relaxing response by Ach in rat pulmonary artery with denuded endothelium was significantly decreased. 2) L-NMMA($10^{-4}M$) pretreatment inhibited Ach($10^{-9}-10^{-5}M$)-induced relaxation, but L-NMMA ($10^{-4}M$) had no effect on relaxation induced by SN($10^{-9}-10^{-5}M$). 3) Pretreatment of the L-arginine($10^{-4}M$) significantly reversed the inhibition of the Ach ($10^{-9}-10^{-5}M$)-induced relaxation caused by L-NMMA($10^{-4}M$) 4) Pulmonary arterial contraction by PE($10^{-6}M$) was stronger in hypoxia than normoxia but relaxing response by Ach($10^{-9}-10^{-5}M$) was decreased, 5) With pretreatment of L-arginine($10^{-4}M$), pulmonary arterial relaxation by Ach($10^{-9}-10^{-5}M$) in hypoxia was reversed to the level of relaxation in normoxia. Conclusion: It is concluded that rat pulmonary arterial relaxation by Ach is dependent on the intact endothelium and is largely mediated by NO. Acute hypoxic pulmonary vasoconstriction is related to the suppression on NO formation in the vascular endothelium.

• Parasites, Hosts and Diseases
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• v.34 no.3
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• pp.197-206
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• 1996

Water extract of Coix locrvmn seeds (Co-Ex) was separated into several components; dissolved with Tris-Cl buffer and the supernatant (WC 1), ammonium sulfate treatment supernatant (WC2) and the pellet nvc31,9AE column chromatography of WC 1 and the peak portions; WC4, WCS and WC6. Murine peritoneal macrophages in DMEM containing 10% heat-inactivated FCS were infected with tachyzoites of ToxopIQsmc gondii, RH strain, in uifo. By adding modulators such as Co-Ex, WC 1,2,3,4.5,6 and LPS or IFN-γ for 24 hrs . toxoplasmastatic activity of macrophages was examined in relation to nitrite production. Nitrite production of macrophages was enhanced especially in the series of WC2, WC1 and the combination sample (WC1 + WC2 + WC3) by order than other components or fractions (WC4, WC5, WC6) tested . Toxoplasmastatic actions such as percentage of the inacrophages infected by T. gonnii and fold increase of T gondii in macrophages showed retroverse relations with the amount of nitrite production; i.e. as nitric oxide (NO) increased the phagocytic index of macrophages and the fold increase of tachyzoites in macrophages decreased . Nitrite (NO-2) production was increased by adding IFN-γ in all cases together with enhancement of biostatic effects. Through the results obtained, it is speculated that some components other than the non-proteinous and defatted components in Coix lacrwmn seeds may contribute to activate macrophages through induction of NO for the biostatic activity.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.671-677
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• 2016

The impregnated alkali metal (Na, K), and the alkali earth metal (Ca, Mg) activated carbons were produced from the bamboo activated carbon by soaking method of alkali metals and alkali earth metals solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. The specific surface area and the pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of the used activated carbon. Carbon-NO reactions were carried out in the nonisothermal condition (the reaction temperature $20{\sim}850^{\circ}C$, NO 1 kPa) and the isothermal condition (the reaction temperature 600, 650, 700, 750, 800, $850^{\circ}C$, NO 0.1~1.8 kPa). As results, the specific volume and the surface area of the impregnated alkali bamboo activated carbons were decreased with increasing amounts of the alkali. In the NO reaction, the reaction rate of the impregnated alkali bamboo activated carbons was promoted to compare with that of the bamboo activated carbon [BA] in the order of BA(Ca)> BA(Na)> BA(K)> BA(Mg) > BA. Measured the reaction orders of NO concentration and the activation energy were 0.76[BA], 0.63[BA(Na)], 0.77[BA(K)], 0.42[BA(Ca)], 0.30 [BA(Mg)], and 82.87 kJ/mol[BA], 37.85 kJ/mol[BA(Na)], 69.98 kJ/mol[BA(K)], 33.43 kJ/mol[BA(Ca)], 88.90 kJ/mol [BA(Mg)], respectively.