• Journal of Life Science
• /
• v.30 no.2
• /
• pp.156-161
• /
• 2020

Since industrialization, the production and utilization of various chemicals has contributed to improving the quality of our lives, but the subsequent discharge of massive waste is inevitable, and environmental pollution is becoming more serious every day. Exposure to chemicals as a result of environmental pollution is having a negative effect on human health and the ecosystem, and cleaning up the polluted environment that can affect our lives is a very important issue. Toxic aromatic compounds have been detected frequently in soil, groundwater, and wastewater because of the extensive use of oil products, and phenol, which is used to produce synthetic resins, textiles, and dyes, is one of the major pollutants, along with insecticides and preservatives. Phenol can cause dyspnea, headache, vomiting, mutation, and carcinogenesis. Phenol-degrading bacterium DWB-1-8 was isolated from the activated sludge of textile wastewater; this strain was identified as Comamonas testosteroni by 16S rRNA gene sequencing. The optimal culture conditions for the cell growth and degradation of phenol were 0.7% K₂HPO₄, 0.6% NaH₂PO₄, 0.1% NH₄NO₃, 0.015% MgSO₄·7H₂O, 0.001% FeSO₄·7H₂O, an initial pH of 7, and a temperature of 30℃. The strain was also able to grow by using other toxic compounds, such as benzene, toluene, or xylene (BTX), as the sole source of carbon.

• Childhood Kidney Diseases
• /
• v.14 no.2
• /
• pp.203-209
• /
• 2010

Purpose : It has been a common medical practice to use prophylactic antibiotics to prevent recurrent urinary tract infections (UTI) in high risk situations such as urinary tract obstruction, vesicoureteral reflux, neurogenic bladder, or urinary stones. But sometimes, we meet difficult situation of breakthrough infections (BI) which might cause new or progressive renal scarring. The clinical characteristics of children contracting breakthrough UTI experienced in a single center were studied. Methods : The study was done retrospectively through medical records of 150 pediatric patients who had been cared in pediatric and urologic clinics of Pusan National University Hospital from Jan. 2001 till June 2006 and had prophylactic antibiotics to prevent recurrent UTI. Results : The starting age of prophylactic antibiotics of 150 patient was 1-76 months, and median age was 5 months. The BI developed 61 times in 43 patients (28.7%), 1.5 times per 100 patient-months. The BI occurred more frequently in patients with higher grade of VUR, and in the cases with abnormal DMSA scan. Co-trimoxazole was more effective than 2nd and 3rd generation cephalosporins to prevent UTI. The distribution of causative organisms was more diverse than usual UTI. The causative organisms were sensitive to the antibiotics used for prophylaxis in 29.5%, and resistant in 59.1%. After experience of BI, 40 percents of patients went to the surgical treatment including endoscopic injection of Deflux, 35% to new antibiotics for prophylaxis, 26% remain on the same antibiotics as the previous one. Conclusion : Based on our study results, preexisting renal scar might be one of the factors which should be considered in favor of early surgical interventions of VUR. Poor compliance and wrong selection of antibiotics such as cephalosporins are important underlying causes of breakthrough UTIs.

• Journal of Soil and Groundwater Environment
• /
• v.8 no.2
• /
• pp.62-69
• /
• 2003

The aim of research is the evaluation of the $Cr^{6+}$ emission features of the liquid injection through emission experiments in varying conditions, based on a field-mixing ratio. The results showed that the content of $Cr^{6+}$ content in cement measured had an Ordinary Potland Cement (OPC) of 25.3 mg/kg, which constitute the largest portion among the other materials. Likewise, the emission experiment of homo-gel and sand-gel generally satisfied the standard of KSLT (Korea Standard Leaching Test) in waste of 1.5 mg/L, but in case of the standard of KSLT in soil the emission of OPC $Cr^{6+}$ of 4.85 mg/kg. These conditions is a little exceeded the criteria in the ‘Ga’ area in terms of Korea Soil Environmental Preservation Law. In addition, results generated by the mock-up injection facilities revealed that $Cr^{6+}$ emission increased as Water/Cement and injection pressure increased. At injection pressure higher than 4 kg/㎤, $Cr^{6+}$ emission exceeded the water preservation standard of 0.5 mg/L. Similarly, a pattern experiment of C $r^{6+}$ emission according to pH was conducted, in order to evaluate the $Cr^{6+}$ emission features of grout materials in leachate below pH 5 such as pH 4 acid rain or landfill. Results show that $Cr^{6+}$ emission dramatically increased in high acidic or basic state. It indicates that $Cr^{6+}$ emission will probably increase in an environment where grout materials are injected. On the other hand, concentration of leachate was determined in areas where grout materials are used. The results show that the concentration of emission in an ultra purity condition does not manifest intensity, and is affected in the OPC>MC>SC order. It means that the pollutants or $Cr^{6+}$ emission increases with decreasing concentration. As such, $Cr^{6+}$ emission will probably exceed the countermeasure criteria according to the types of gout materials. Similarly, high pressure or injection will cause increased $Cr^{6+}$ emission. Therefore, the selection of materials or mixing ratio should be considered in general as well as according to specific industries, based on the strength and pH of $Cr^{6+}$ emission.

• Horticultural Science & Technology
• /
• v.32 no.3
• /
• pp.353-358
• /
• 2014

Hot water dipping test was conducted for chicon to restrict red discoloration of its basal part which impairs the product value during sales. Hot water dipping treatment was given to chicon for 4 min and for 8 min at $38^{\circ}C$ and for 2 min and 4 min at $42^{\circ}C$, and for 1 min and 2 min at $45^{\circ}C$, along with control (for one min at $20^{\circ}C$). The red discoloration indices of basal part of chicon during sensory evaluation on the sixth day of storage under the storage temperature at $10^{\circ}C$ was lower at $42^{\circ}C$ for 2 min, $42^{\circ}C$ for 4 min and $45^{\circ}C$ for 1 min treatments. The color change value of the basal part in chicon measured by colorimeter showed that the lowest ${\Delta}a^*$ and ${\Delta}h$ were maintained in the basal part of chicon treated at $42^{\circ}C$ for 2 min. Whereas, color changes in $42^{\circ}C$ for 2 min and $45^{\circ}C$ for 1 min treatments were significantly low as compared with that of control. The contents of total phenolic compounds which are the substances that cause red discoloration of basal part in chicon were lowest at $42^{\circ}C$ for 2 min, $42^{\circ}C$ for 4 min and $45^{\circ}C$ for 1 min treatments. The activity of phenylalanine ammonia lyase (PAL) resposible for in the synthesis of phenolic substances was the least in $42^{\circ}C$ for 2 min treatment. Whereas, PAL activity of the chicons treated a t $42^{\circ}C$ for 2 min and at $45^{\circ}C$ for 1 min were significantly lower than that of control. However, red discoloration was progressed as similar level with that of control in the basal part of chicon at $45^{\circ}C$ for 2 min. The contents of total phenolic compounds and PAL activity in this treatment were not significantly different from those in control. The polyphenol oxidase (PPO) activity which causes red discoloration of cut tissues was low in all the treatments including $42^{\circ}C$ and $45^{\circ}C$ treatment at which no inhibition effects of the red discoloration of basal part of chicon were observed. When the correlation coefficient between each investigated index was tested, most of them showed high correlation except the PPO activity and particularly and the red discoloration index and sensory evaluation ${\Delta}h$ values, and PAL activity and total phenolic compounds content were $r=0.927^{**}$, and $r=0.942^{**}$, respectively.

• Economic and Environmental Geology
• /
• v.50 no.5
• /
• pp.375-387
• /
• 2017

Amphibolite-hosted Fe-Ti mineralization at the Soyeonpyeong Island, located in central western part of the Korean Peninsula is a typical orthomagmatic Fe-Ti oxide deposit in South Korea. The amphibolite intruded into NW-SE trending Precambrian metasedimentary rocks. Lower amphibolite is characterized by igneous layering, consisting of feldspar-dominant and amphibole-Fe-Ti oxide-dominant layers. The igneous layering shows complicated and/or sharp contact. In contrast, upper amphibolite has a more complicated lithofacies (garnet-bearing, coarser, and schistose), and massive Fe-Ti oxide ore alternates with schistose amphibolite. NS- and EW-trending fault systems lead to redistribute upper amphibolite-hosted Fe-Ti orebody and igneous layering of lower amphibolite, respectively. The whole-rock compositions of amphibolite and Fe-Ti oxide ore reflect their constituent minerals. Amphibolite shows significantly positive Eu anomalies whereas Fe-Ti oxide ore has weak negative Eu anomalies. Plagioclase (Andesine to oligoclase) and Fe-Ti oxide minerals have constant composition regardless of their distribution. Amphibole has a compositionally variable but it doesn't reflect the chemical evolution. Mineral compositions within individual layers and successive layers are relatively constant not showing any stratigraphic evolution. This suggests that there are no successive injections of Fe-rich magma or assimilation with Fe-rich country rocks. Contrasting Eu anomalies between amphibolite and Fe-Ti oxide ore also suggest that extensive plagioclase fractionation during early crystallization stage cause increase in $Fe_2O_3/FeO$ ratio and overall Fe contents in the residual magma. Thus, Fe-rich residual liquids may migrate at the upper amphibolite by filter pressing mechanism and then produce sheeted massive Fe-Ti mineralization during late fractional crystallization.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.17 no.3
• /
• pp.227-235
• /
• 2015

Using eddy covariance method, net ecosystem exchange (NEE) of $CO_2$ ($F_{CO_2}$), $H_2O$ (LE), and sensible heat (H) can be approximated as the sum of eddy flux ($F_c$) and storage flux term ($F_s$). Depending on strength and distribution of sink/source of scalars and magnitude of vertical turbulence mixing, the rates of changes in scalars are different with height. In order to calculate $F_s$ accurately, the differences should be considered using scalar profile measurement. However, most of flux sites for agricultural lands in Asia do not operate profile system and estimate $F_s$ using single-level scalars from eddy covariance system under the assumption that the rates of changes in scalars are constant regardless of the height. In this study, we measured $F_c$ and $F_s$ of $CO_2$, $H_2O$, and air temperature ($T_a$) using eddy covariance and profile system (i.e., the multi-level measurement system in scalars from eddy covariance measurement height to the land surface) at the Chengmicheon farmland site in Korea (CFK) in order to quantify the differences between $F_s$ calculated by single-level measurements ($F_s_{-single}$ i.e., $F_s$ from scalars measured by profile system only at eddy covariance system measurement height) and $F_s$ calculated by profile measurements and verify the errors of NEE caused by $F_s_{-single}$. The rate of change in $CO_2$, $H_2O$, and Ta were varied with height depending on the magnitudes and distribution of sink and source and the stability in the atmospheric boundary layer. Thus, $F_s_{-single}$ underestimated or overestimated $F_s$ (especially 21% underestimation in $F_s$ of $CO_2$ around sunrise and sunset (0430-0800 h and 1630-2000 h)). For $F_{CO_2}$, the errors in $F_s_{-single}$ generated 3% and 2% underestimation of $F_{CO_2}$ during nighttime (2030-0400 h) and around sunrise and sunset, respectively. In the process of nighttime correction and partitioning of $F_{CO_2}$, these differences would cause an underestimation in carbon balance at the rice paddy. In contrast, there were little differences at the errors in LE and H caused by the error in $F_s_{-single}$, irrespective of time.

• Korean Journal of Health Education and Promotion
• /
• v.1 no.1
• /
• pp.57-71
• /
• 1983

Sex education is necessary for the youth that they should have an adequate sexual knowledge, attitudes and behaviors in their adolescent period. Four major objectives of this study are as follows; 1. To know the level of sexual knowledge of commercial girl's high school students in Seoul. 2. To know their actual state for the attitudes and behaviors toward sex. 3. To compare the sexual knowledge, attitudes and behaviors of day time school students with those of night time school students. 4. To compare the factors associated with their sexual knowledge, attitudes and behaviors with the individual level. Data were collected on 986 students in Seoul from April 1 to April 10, 1983. As the result of this survey, the following conclusions were obtained. 1. The level of sexual knowledge. (1) The level of knowledge of day time high school students about the physiology of female and pregnancy is shown higher than those of night time students. 64.2% of the respondents are aware of the organ producing ovum. 56.4% the ovulation period. 95.6% the cause of pregnancy. 74.5% the pregnantable period and 12.7% the place of fetilization. (2) Out of 986 respondents. 71.8% knew about contraceptive method correctly, and day time school students knew litter better than night time school students, by showing 73.9% and 69.7% respectively. They knew about contraceptive method with 'oral pills'. 'menstrual cycles', 'condoms'. and 'loops' in the same order. 3) Kinds of veneral disease was correctly known by 37.9%. Day time students knew much better than night time school students. by showing 67.8% and 7.9%. respectively. Transmission method of veneral disease was correctly known by 28.3%. Day time students knew much better than night time students, by showing 51.2% and 5.3%, respectively. (4) The major information source of sexual knowledge was 'book and magazine' (39.9%) and 'friends' (27.4%). 2. Actual state of attitudes and behaviors toward sex. (1) Out of 986 respondents, 84.0% answered that premarital purity should be kept. (2) Out of 986 respondents, 60.8% had an acquaintance of the opposite sex. 45.2% of students with opposite sex reported introduction of their friends as the main channel of making an acquaintance of the opposite sex. (3) Of those who responded to this study 13.8% reported having masturbation, 21.5% kissing, 6.2% petting and 3.7% sex intercourse. (4) 64.8% had sexual problems, which was mensturance (27.2%), aquaintance of the opposite sex (25.4%). The main method to solve the problems were consultation with 'friends' and 'books and magazine' percentage being 39.1% and 30.8%, respectively, whereas very small students discussed with 'teachers' and 'parents' percentages being 0.3% and 5.9%, respectively. (5) Out of 986 respondents, 62.2% had experience in educating about sex, the percentage of day time school was higher than that of night time school. (6) 88.2% of students wanted sex education in school, which were 'general information about sex' (35.4%), 'sexual morality and solution of sexual desire' (18.5%), 'aquaintance of the opposite sex' (13.3%) and 'marriage and role of man and woman' (12.4%) in the same order. They wanted to be instructed about sexes in the lecture of physical education, home economics, biology, military training (59.9%), regular curriculum (17.5%), special lecture (16.9%) and by the counselor or school nurse (5.7%). 3. Analyse concerning the factors about the knowledge, attitudes and behaviors. (1) The better school record was, the higher the level of sexual knowledge. (2) Those who have the religion considered the permarital purity more important than those who have not, the percentage showing 86.7% and 80.7%, respectively. (3) The result of dyad analysis of making acquaintance of the opposite sex in the friendship network showed that a high index of the acquaintance of the opposite sex tends to be a high adoption of making one at the individual level in the group, while the low index tends to be a low adoption of making one in the group.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.29 no.2
• /
• pp.139-145
• /
• 2002

In a primary teeth, dental caries is rapidly advanced the pulp disease, because the primary teeth have the thinner and the weaker enamel layer and the wider pulp chamber than relatively the permanent teeth. And the pulps of primary teeth are exposed during caries removal or even they are exposed by unexpected movement of the children or by trauma. For successive pulp treatment in primary teeth, it is necessary to understand completely about multiple canal morphology, variation of root canal anatomy and specific problem related to root formation and resorption of primary teeth. In upper primary molar, canal configuration of mesial root has the most variation same as upper molar. If not canal treatment is completely, most of all endodontic treatment should be failed. In a clinical case report, upper primary molars existed persistent pain or bleeding during treatment were founded the second MB canal and were performed the endodontic treatment of theirs. As a result, the upper primary molars have no symptom and good prognosis. In the examination of extracted upper primary molar, we found that 8 of 35 teeth(22.8%) in the upper primary first molars and 22 of 33 teeth(66.6%) in the upper primary second molar had the second mesiobuccal canal. It has revealed the high prevalence of two canals in mesiobuccal roots of upper primary molars. The frequency of occurrence of the second mesiobuccal canal must be taken into consideration when endodontic treatment is planned and as a possible cause of otherwise un explained failure.

• Tuberculosis and Respiratory Diseases
• /
• v.59 no.5
• /
• pp.504-509
• /
• 2005

Background : Endobronchial tumors cause life-threatening dyspnea and can lower the quality of life due to central airway obstruction. In those cases with an intraluminal tumor, various bronchoscopic techniques are available for tumor debulking. The therapeutic effect of bronchoscopic electrocautery for palliation in patients with a symptomatic tumor obstruction was studied. Method : Nineteen patients with bronchogenic carcinomas (n=15) and metastatic tumors affecting the bronchi (n=4), between March 2002 and March 2005, were enrolled in this study. Electrocautery was performed under local anesthesia using an electroprobe and diathermic snare. Using flexible bronchoscopy, a follow-up bronchoscopic examination was performed 3-4 days later. Symptom improvement was evaluated by $FEV_1$, FVC and dyspnea score (Modified Borg Category Scale (0~10)), both before and after the electrocautery. Results : The success rate of electrocautery on the follow up examination was 84%. Patients with endoluminal airway lesions had a mean overall decrease in the size of the obstruction to $47.8{\pm}15.7%$. The mean Improvement in the dyspnea score immediately after the endobronchial tumor debulking was $2.78{\pm}1.42$. The average improvements in the $FEV_1$ and FVC after electrocautery were $0.32{\pm}0.19L$ and $0.5{\pm}0.22L$, respectively. There were 2 cases of complications related with electrocautery (one each of pneumothorax and pneumonia). Conclusion : Electrocautery using an electroprobe and diathermic snare was an effective and safe palliative treatment for a symptomatic endoluminal airway obstruction in lung cancer.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.5
• /
• pp.628-636
• /
• 2018

Because large buoys are mainly made of steel, they are heavy and vulnerable to corrosion by sea water. This makes buoy installation and maintenance difficult. Moreover, vessel collision accidents with buoys and damage to vessels due to the material of buoys (e.g., steel) are reported every year. Recently, light buoys adopting eco-friendly and lightweight materials have come into the spotlight in order to solve the previously-mentioned problems. In Korea, a new lightweight buoy with a 7-Nautical Mile lantern adopting expanded polypropylene (EPP) and aluminum to create a buoyant body and tower structure, respectively, was developed in 2017. When these light buoys are operated in the ocean, the visibility and angle of light from the lantern installed on the light buoys changes, which may cause them to function improperly. Therefore, research on the performance of light buoys is needed since the weight distribution and motion characteristics of these new buoys differ from conventional models. In this study, stability estimation and motion analyses for newly-developed buoys under various environmental conditions considering a mooring line were carried out using ANSYS AQWA. Numerical simulations for the estimation of wind and current loads were performed using commercial CFD software, Siemens STAR-CCM+, to increase the accuracy of motion analysis. By comparing the estimated maximum significant motions of the light buoys, it was found that waves and currents were more influential in the motion of the buoys. And, the estimated motions of the buoys became larger as the sea state became worser, which might be the reason that the peak frequencies of the wave spectra got closer to those of the buoys.