• Applied Chemistry for Engineering
• /
• v.28 no.1
• /
• pp.101-111
• /
• 2017

Mineral carbonation is a technology in which carbonates are synthesized from minerals including serpentine and olivine, and industrial wastes such as slag and cement, of which all contain calcium or magnesium when reacted with carbon dioxide. This study aims to develop the mineral carbonation technology for commercialization, which can reduce environmental burden and process cost through the reduction of carbon dioxide using steel slag and the slag reuse after calcium extraction. Calcium extraction was conducted using NH4Cl solution for air-cooled slag and convert slag, and ${\geq}98%$ purity calcium carbonate was synthesized by reaction with calcium-extracted solution and carbon dioxide. And we conducted experimentally to minimize the quantity of by-product, the slag residue after calcium extraction, which has occupied large amount of weight ratio (about 80-90%) at the point of mineral carbonation process using slag. The slag residue was used to replace silica sand in the manufacture of cement panel, and physical properties including compressive strength and flexible strength of panel using the slag residue and normal cement panel, respectively, were analyzed. The calcium concentration in extraction solution was analyzed by inductively coupled plasma optical emission spectrometer (ICP-OES). Field-emission scanning electron microscope (FE-SEM) was also used to identify the surface morphology of calcium carbonate, and XRD was used to analyze the crystallinity and the quantitative analysis of calcium carbonate. In addition, the cement panel evaluation was carried out according to KS L ISO 679, and the compressive strength and flexural strength of the panels were measured.

• Korean Journal of Ecology and Environment
• /
• v.39 no.2 s.116
• /
• pp.145-156
• /
• 2006

The objective of this study was to evaluate biological health conditions and physicochemical status using multi-metric models at five sites of the Keum-Ho River during August 2004 and June 2005. The research approach was based on a qualitative habitat evaluation index (QHEI), index of biological integrity (IBI) using fish assemblage, and long-term chemical data (1995 ${\sim}$ 2004), which was obtained from the Ministry of Environment, Korea. For the biological health assessments, regional model of the IBI in Korea (An,2003), was applied for this study. Mean IBI in the river was 30 and varied from 23 to 48 depending on the sampling sites. The river health was judged to be "fair condition", according to the stream health criteria of US EPA (1993) and Barbour et al. (1999). According to the analysis of the chemical water quality data of the river, BOD, COD, conductivity, TP, TN, and TSS largely varied epending on the sampling sites, seasons and years. Variabilities of some parameters including BOD, COD, TP, TN, and conductivity were greater in the downstream than in the upstream reach. This phenomenon was evident in the dilution by the rain during the monsoon. This indicates that precipitation is a very important factor of the chemical variations of water quality. Community analyses showed that species diversity index was highest (H=0.78) in the site 1, while community dominance index was highest in the site 3, where Opsariichthys uncirostris largely dominated. In contrast, the proportions of omnivore and tolerant species were greater in the downstream reach, than in the upstream reach. Overall, this study suggests that some sites in the downstream reach may need to restore the aquatic ecosystem for better biological health.

• The Journal of the Korea Contents Association
• /
• v.11 no.5
• /
• pp.252-259
• /
• 2011

To identify the effects of the application of the adaptive statistical iterative reconstruction (ASIR) technique in combination with the other two factors of body mass Index (BMI) and tube potential on radiation dose in cardiac CT. The patient receiving operation the cardiac CT examination was divided four groups into according to kVp.[A group(n=20), Non-ASIR, BMI < 25, 100 kVp; B group(n=20), Non-ASIR, BMI > 25, 120 kVp; C group(n=20), 40% ASIR BMI < 25, 100 kVp; D group(n=20), 40% ASIR, BMI > 25, 120 kVp] After setting up the region of interest in the main artery central part and right coronary artery and left anterior descending artery, the CT number was measured and an average and standard deviation were analyzed. There were A group and the difference which the image noise notes statistically between C. And A group was high so that the noise could note than C group (group A, 494 ${\pm}$ 32 HU; group C, 482 ${\pm}$ 48 HU: P<0.05) In addition, there were B group and the difference noted statistically between D. And B group was high so that the noise could note than D group (group B, 510 ${\pm}$ 45 HU; group D, 480 ${\pm}$ 82 HU: P<0.05). In the qualitative analysis of an image, there was no difference (p>0.05) which a group, B group, C group, and D as to average, A group 4.13${\pm}$0.2, B group 4.18${\pm}$0.1, and C group 4.1${\pm}$0.2 and D group note statistically altogether with 4.15${\pm}$0.1 as a result of making the clinical evaluation according to the coronary artery segments. And the inappropriate image was shown to the diagnosis in all groups. As to the radiation dose, a group 8.6${\pm}$0.9 and B group 14.9${\pm}$0.4 and C group 5.8${\pm}$0.5 and D group are 10.1${\pm}$0.6 mSv.

• Journal of Oral Medicine and Pain
• /
• v.38 no.2
• /
• pp.137-142
• /
• 2013

Oral Medicine includes temporomandibular disorder, orofacial pains such as neuropathic pain, soft tissue diseases, halitosis, laser treatment, snoring, sleep apnea and identification through forensic dentistry etc. Such diseases are relatively common and cause great inconvenience and pain to the patients, as well as incur fatal health scare at times. In terms of oral medicine, the number of orofacial patients is growing due to a change in the life style and an increased stress as time goes in contemporary society and the demand of areas requiring oral medical professionalism, such as soft tissue lesions, snoring and sleep apnea, forensic dentistry evaluation and others are rapidly ascending. Consequently, among the areas in dental science, the calls for the expertism in oral medicine and its role are mounting. Analyzing the distribution according to disease entity, symptoms, duration of disease, and the prehistory courses of new patients visiting the department of oral medicine in a year provides information of the role and the relative importance of oral medicine in prospect and enables effective diagnosis and treatments for the patients. Therefore, in the present study, by analyzing new patients visiting the oral medicine clinic in our dental hospital for a year and by evaluating the role and the professionalism in future oral medicine, the authors concluded the followings: 1. It was founded that new patients to oral medicine mainly had temporomandibular disorders, soft tissue diseases, and neuropathic pains. 2. The number of patients with temporomandibular disorder appeared to be the highest percentage and the order within this was the patients with combined disorders, muscle disorder, and internal derangement of joint disc. 3. The number of patients with xerostomia appeared to be the highest percentage within soft tissue disease, followed by lichen planus and recurrent apthous ulcers. 4. The number of patients with burning mouth syndrome appeared to be the highest percentage within neuropathic pain.

• The Journal of Korean Academy of Prosthodontics
• /
• v.50 no.2
• /
• pp.128-134
• /
• 2012

Purpose: The purpose of this study was to compare the screw joint stability between the CADCAM custom-made implant abutment and the prefabricated implant abutment by measuring the reverse torque value after cyclic loading. Materials and methods: Twelve screw type implants (Implantium, Dentium Co., Seoul, Korea) were embedded in aluminum cylinder with acrylic resin. The implant specimens were equally divided into 3 groups, and connected to the prefabricated titanium abutments (Implantium, Dentium Co., Seoul, Korea), CADCAM custom-made titanium abutments (Myplant, Raphabio Co., Seoul, Korea) and CADCAM custom-made zirconia abutments (Zirconia Myplant, Raphabio Co., Seoul, Korea). The CAD-CAM milled titanium crown (Raphabio Co., Seoul, Korea) was cemented on each implant abutment by resin cement. Before cyclic loading, each abutment screw was tightened to 30 Ncm and the reverse torque value was measured about 30 minutes later. After the crown specimen was subjected to the sinusoidal cyclic loading (30 to 120 N, 500,000 cycles, 2 Hz), postloading reverse torque value was measured and the reverse torque loss ratio was calculated. Kruskal-Wallis test was used for statistical analysis of the reverse torque loss ratio. Results: The CADCAM custom-made titanium abutments presented higher values in reverse torque loss ratio without statistically significant differences than the prefabricated titanium abutments ($P$>.05). Reverse torque loss ratio of the custom-made zirconia abutments was significantly higher compared to that of the prefabricated titanium abutments ($P$=.014). Conclusion: Within the limitation of the present $in-vitro$ study, it was concluded that there was no significant difference in screw joint stability between the CADCAM custom-made titanium abutments and the prefabricated titanium abutments. On the other hand, the CADCAM custom-made zirconia abutments showed lower screw joint stability than prefabricated titanium abutments.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.1
• /
• pp.91-98
• /
• 2007

The aim of this study was to examine the difference of the depth of sedation using the Bispectral index assessment with and without the added submucosal Midazolam to oral Chloral hydrate and Hydroxyzine for pediatric patients. Twenty seven sedation cases were performed in this study Selection criteria included good health(ASA I), 2 to 6 years of age, the need for sedation to receive dental treatment including anesthesia, and restorative procedure over at least two teeth. Patients were randomly classified into one group taking oral Chloral hydrate(60 mg/kg) and Hydroxyzine(1 mg/kg) and the other group recieving Chloral hydrate(60 mg/kg), Hydroxyzine(1 mg/kg) and submucosal Midazolam(0.1 mg/kg). Nitrous Oxide(50%) was used for both group during sedation. Patients were monitored using a pulse oximeter and a Bispectral monitor. A behavior scale was rated as quiet(Q), crying(C), movement(M), or struggling(S) every 2 minutes watching a recorded videotape. Analysis showed a significant difference in mean Bispectral index and SD during sedation across two groups(P<0.001). The group of patients injected with submucosal Midazolam in addition to oral Chloral hydrate and Hydroxyzine showed a lower mean Bispectral index and a narrower SD. PR and SpO2 for both groups remained within the normal values. Submucosal Midazolam improved the sedation quality by deepening sedation depth without compromising safety and enabled the sedation pattern to be kept more stable.

• Sleep Medicine and Psychophysiology
• /
• v.3 no.1
• /
• pp.56-67
• /
• 1996

Objectives : This study was designed to find clinical factors that could be differentiated by the lateralization of lesion and also find clinical factors to predict the lateralization of lesion. Methods : The subjects were 65 cooperative inpatients and outpatients with non-traumatic subcortical cerebrovascular disease without neurologic and psychiatric history from January 1995 to September 1995 ; 48 patients in Kyung Hee University, Oriental Medicine Hospital, 35 patients in Anam Hospital, Korea University were examined as subjects, but authors excluded 20 patients whose data were incomplete or who had uncertain lesions on brain CT or MRI. The 65 patients were divided into three groups-group with left hemispheric lesion, group with right hemispheric lesion, group with both hemispheric lesion-according to the finding of brain imaging study. Their cognitive functions were evaluated by the Benton Neuropsychological Assessment(BNA), their subjective neurobehavioral symptoms by Symptom Check List-90-R(SCL-90-R), their objective neurobehavioral symptoms by Neurobehavioral Rating Scale, and their daily living functions by Geriatric Evaluation by Relative's Rating Instrument(GERRl) and Instrumental Activities of Daily Living Scale(IADLs). Results : The results were as follows : 1) The results of cognitive function test indicated that the group with right hemispheric lesion showed low functions in Tactile Form Perception(left), the group with left hemispheric lesion showed low functions in Finger localization(right), the group with right hemispheric lesion showed low functions in Finger Localization(left). 2) Though, there were little significant differences in subjective neurobehavioral symptoms, the group with right hemispheric lesion showed higher scores in all symptoms except hostility. 3) Though, there were little significant differences in objective neurobehavioral symptoms, the group with both hemispheric lesion showed higher scores in cognition, guilty/disinhibition, the group with left hemispheric lesion showed higher scores in lability of mood, the group with right hemispheric lesion showed highest scores in psychotism, neurotism, agitation-hostility and decreased motivation/emotional withdrawal. 4) There were little significant differences among three groups in Daily Living Functions, but the group with right hemispheric lesion showed the lowest functions in Instrumental Activities of Daily Living. 5) As a result of discriminant analysis on each factor's contribution to the prediction of lesion, Finger Localization(left), Phoneme Discrimination and Tactile Form Perception(right) showed that they had the potentiality to predict lesion. Conclusion : The results suggest that there are little significant differences among the groups of three non-traumatic subcortical cerebrovascular disease in cognitive functions, but the group with right hemispheric lesion showed more serious and various changes in subjective and objective neurobehavioral symptoms, and showed low functions in Instrumental Activities of Daily Living. This results suggest the possibility that the decline of the daily living function in the group with right hemispheric lesion were due to various symptoms, not due to cognitive dysfunction. The confirmation of the possibility should be worked out through the follow-up study of some groups containing cortical lesion. Apart from these findings, Finger Localization, Tactile Form Perception(right) and Phoneme Discrimination suggest that they can be used as clinically valuable cognitive parameters that predict the lateralization of lesion in non-traumatic cerebrovascular disease.

• Survey Research
• /
• v.6 no.1
• /
• pp.1-38
• /
• 2005

Considering the importance of corruption index measurement model and the diffusion of popular awareness about the importance of anti-corruption, this research compared and analyzed existing corruption index measurement models. This paper has selected "Anti-Corruption Index model(ACI model)" that was developed by Seoul Development Institute and "CCEJ's Corruption Index model" which is under use by the Citizens' Coaltion for Economic Justice. These two models were analyzed in terms of appropriateness of 'the indicator and index choice method', 'the research design' and 'the use of statistical data'. This analysis shows that two models have some problems. First, at the level of indicator and index choice method, the indicators of CCEJ's corruption index model is too atomized and redundant. As not putting weight of indicator, it did not consider importance of each indicator. Citizens who evaluated the level of corruption didn't participate in the weight evaluation team, which results in failure of the model to reflect the citizens' opinion. Also, because the question about Seoul Metropolis' corruption level is not included, it is not detected difference between real corruption level and perceptive corruption level. Second, in terms of appropriateness of research design, the sample of the CCEJ' corruption index model is too small to get credibility. The objectivity of research method seems to be low because survey was performed by exit interview. In addition, 38 items are overfull in the questionnire of CCEJ's corruption index model compare to 13 items in ACI model. Also, in making up questions, the terms are redundant and unobvious. Third, in regarding with feasibility of the statistical data, the CCEJ's corruption index model uses regulation data for disciplinary punishment of 25 local governments in Seoul from 1995 to 1999. But, it is common ideas of scholars that statistical data indicates the tip of an iceberg in corruption. So for using a statistical data, it needs a data of enough quantity and has a high level credibility. In addition, objective method of giving weight is not developed. In this point of view, the use of statistical data has some limits. To solve this problem, ① objective data should be included in the indicators, ② various indicators should be developed and ③ a method of giving weight should be improved.

• Tuberculosis and Respiratory Diseases
• /
• v.46 no.6
• /
• pp.846-855
• /
• 1999

Background : Secondary pulmonary hypertension is an important final endpoint in patients with chronic hypoxic lung disease, accompanied by deterioration of pulmonary hemodynamics. The clinical diagnosis of pulmonary hypertension and/or cor pulmonale could be difficult, and simple noninvasive evaluation of pulmonary artery pressures has been an relevant clinical challenge for many years. Doppler echocardiography might to be a more reliable method for evaluating pulmonary hemodynamics in such patients in terms of the accuracy, reproducibility and easiness for obtaining an appropriate echocardiographic window than M-mode echocardiography. The aim of this study was to assess echocardiographic parameters associated with pulmonary arterial hypertension, defined by increasing right ventricular systolic pressure(RVSP), calculated from trans-tricuspid gradient in patients with chronic hypoxic lungs. Method : We examined 19 patients with chronic hypoxic lung disease, suspected pulmonary hypertension under the clinical guidelines by two dimensional echocardiography via the left parasternal and subcostal approach in a supine position. Doppler echocardiography measured RVSP from tricuspid regurgitant velocity in continuous wave with 2.5MHz transducer and acceleration time(AT) on right ventricular outflow tract in pulsed wave for the estimation of pulmonary arterial pressure. Results : On echocardiography, moderate to severe degree of pulmonary arterial hypertension was defined as RVSP more than 40mmHg, presenting tricuspid regurgitation. Increased right ventricular endsystolic diameter and shortened AT were noted in the increased RVSP group. Increased RVSP was correlated negatively with the shortening of AT. Other clinical data, including pulmonary functional parameters, arterial blood gas analysis and M mode echocardiographic parameters were not changed significantly with the increased RVSP. Conclusion : These findings suggest that shortened AT on pulsed doppler can be useful when quantifying pulmonary arterial pressure with increased RVSP in patients with chronic lung disease with hypoxemia. Doppler echocardiography in pulmonary hypertension of chronic hypoxic lungs is an useful option, based on noninvasiveness under routine clinical practice.

• Tuberculosis and Respiratory Diseases
• /
• v.46 no.6
• /
• pp.775-785
• /
• 1999

Background : The herbicide paraquat can cause severe lung injury and fibrosis in experimental animals. In this study we have investigated the changes in lung endothelin-1(Et-1) levels and immunohistochemical localization in relation to treatment with cyclophosphamide and methylprednisolone in paraquat induced pulmonary fibrosis in guinea pigs. Material and methods : 29 male Hartley guinea pigs were divided into 4 groups. Group I was normal control. Paraquat was instilled into the lung of guinea pig of group II, III and IV unilaterally. Group II was treated with cyclophosphamide and methylprednisolone. Group III was treated with methlprednisolone. Group IV was not treated. The degree of fibrosis was evaluated by H-E stains and Masson's trichrome stains and cell activity was assessed by Et-1 immunohistochemical stains. Statistical evaluation was performed using the Kruskawallis oneway analysis. Results : Paraquat induced an increase in numbers of fibroblasts and total amount of lung collagen in Group IV compared to the normal controls. There was no significant difference in total numbers of fibroblasts between any of paraquat instilled groups, but there was significant increase in total amount of collagen in Group IV compared to group II and III (p<0.05). The treatment of cyclophosphamide and methyprednisolone suppressed the growths of both fibroblasts and collagen, but this suppression was stastically significant only in the case of collagen Et-1 immunoreactivities of bronchial epithelium, type II pneumocytes, endothelial cells and fibroblast in group II and III were decreased compared to those in group IV. Conclusion : These results demonstrate that Et-1 is an important contributing factor in the pathogenesis of pulmonary fibrosis. Et-1 is synthesized and released by bronchial epithelium, Type II pneumocyte, endothelial cells, alveolar macrophages and fibroblasts. Especially they are associated with alveolar macrophage and fibroblasts. We conclude that combined therapy of cyclophosphamide and methylprednisolone are more effective in the control of Et-1 expression and collagen deposition.