• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.1
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• pp.27-36
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• 2019

Purpose: The aims of this study were to evaluate the dentist's awareness and the actual status of infection control of noncritical dental instruments. Materials and Methods: 40 dental clinics in Daejeon, South Chungcheong, North Chungcheong and North Jeolla provinces were surveyed. The questionnaire was delivered to the dentists belonging to those clinics, and the awareness and the practice of infection control were examined. The microbial contamination on the surface of five noncritical instruments (impression gun, light curing unit, 3-way syringe, shade guide, and dental floss dispenser) used by them was measured with an ATP luminometer. Correlation analysis between the awareness and the actual state of infection control was conducted. Results: Awareness and frequency of infection control was highest in the 3-way syringe. Surface disinfection using disinfectant was most frequent in all instruments. 3-way syringes and shade guides were less contaminated than impression guns, light curing units, and dental floss dispensers. Conclusion: 3-way syringes had a significant correlation between user awareness of infection control and surface contamination, and the higher awareness, the lower the contamination measurement was shown.

• Journal of Appropriate Technology
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• v.6 no.2
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• pp.238-255
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• 2020

As COVID-19, which occurred at the end of 2019, has become a global pandemic, it has emerged as an unprecedented event that quickly destroys a nation's medical and healthcare system in both developed and developing countries. In the 21st century, most of the civil society that aimed for hyperconnected society is facing a new crisis that has not been experienced so far. Indeed, lack of personal protective equipment, isolation of clustered communities, disruption of medical systems necessary for diagnosis and treatment, and disruption of educational and economic activities due to social isolation are emerging. Since the COVID-19 has occurred, many of the difficulties that have occurred in the past six months indicate the basic infrastructure a society should have particularly in a pandemic. These include personal protective equipment (PPE), decontamination and quarantine tools essential for effective response, rapid and precise large-scale diagnosis, medical devices required for patient care, and identification and fast and wide on-line networks that can be used in social isolation. In this first part, we would like to introduce some representative examples of 1) personal protective equipment, 2) prevention of personal and community health, 3) social response through big data and networks within the framework of appropriate technology.

• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.232-237
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• 2022

The present study investigated the bactericidal effects of chlorine dioxide (CD) and electrolyzed water (EW) on pathogenic bacteria, such as Bacillus cereus, Staphylococcus aureus, Salmonella Typhimurium, and Escherichia coli O157:H7, by treatment them with CD and EW, respectively, for 0, 2, 4, 6, 8, and 10 min. Additionally, the sensitivities of Gram-positive (B. cereus and S. aureus) and Gram-negative (S. Typhimurium and E. coli O157:H7) to CD and EW were compared, respectively. In CD, the D-values for B. cereus, S. aureus, S. Typhimurium, and E. coli O157:H7 were 1.85±0.64, 2.06±0.85, 2.26±0.89, and 2.59±0.40 min, respectively. In EW, the D-values for B. cereus, S. aureus, S. Typhimurium, and E. coli O157:H7 were 2.13±0.32, 1.64±0.64, 1.71±0.32, and 1.86±0.36 min, respectively. All strains decreased consistently for 10 min in both CD and EW. However, the D-values of each bacterial species did not differ significantly between CD and EW (P>0.05). When comparing the bactericidal effect of CD and EW, no difference in D-value was observed, even though the pH and available chlorine concentration of CD were significantly lower than those of EW. These data could be used for the application of CD and EW in the food industry, considering characteristics such as the selection of optimal disinfectants, determination of optimal concentrations, and sensitivity to disinfection targets.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.37-37
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• 2023

천마(天麻, Gastrodia elata Blume)는 난초과(蘭草科, Orchidaceae)에 속하는 식물로 잎과 뿌리가 없어 탄소동화능력이 없으며, 뽕나무버섯균과 공생하는 기생식물이다. 천마는 노지재배 시 혹한, 폭우 등 기상환경에 따른 연차간 수량성 차가 673~1,175kg/10a로 크고, 연작에 따른 수량성이 연작 1회 시 29%, 연작 2회 시 68%가 감소하는 경향을 보이고 있다. 최근 기후변화 대응으로 비가림시설재배가 이뤄지고 있으나, 비가림 시설재배 또한 연작장해가 발생하고 있다. 따라서, 본 연구는 비가림시설을 활용한 천마 재배의 연작장해 경감을 위해 태양열(6~10월, 비닐피복) 및 토양훈증(메탐소듐, 30 L/1,000 m²)으로 토양소독 처리를 하였고, 윤작(수단그라스)을 대조구로 설정하여 토양 화학성, 미생물상 및 수량성을 분석하였다. 토양소독 전·후 토양내 화학성을 분석한 결과, 비가림시설재배 시 토양 화학성의 변화는 거의 없었다. 토양소독 후 metagenome 분석 결과, JCR21(윤작), JCS21(태양열), JCF21(토양훈증)의 시료로부터 확보한 총 read는 598,425개였으며, 이 중에서 Eukaryota로 분류되지 않은 read는 2,397개(0.4%), no hit, not assign된 read는 17,094개 (2.9%), Bacteria로 분류된 read는 281,391개(47.0%), Eukaryota로 분류된 read는 총 297,543개(49.7%)였다. JCR21은 전체 read의 35.0%, JCS21은 34.0%, JCF21은 31.0%를 차지했고, Eukaryota는 JCR21 대비 JCS21, JCF21에서 각각 9.9%, 18.9% 낮았다. 그리고, Bacteria는 JCR21 대비 JCF21은 5.4% 감소하였으나, JCS21은 1.4% 증가하였다. 이 중 Eukaryota에서 종(species)명까지 정확하게 밝혀진 것은 27종이었고 속(genus) 으로는 18속이었다. JCF21은 전체 read의 30.2%, JCS21은 33.8%, JCR21은 36.0%를 차지했고, JCF21 포장은 토양훈증으로 JCS21에 비해 3.6%, JCR21에 비해 5.8%까지 균수가 감소함을 알 수 있었다. 대체적으로 발견된 균은 고르게 분포하고 있었으나 초작지, 연작 1회지, 연작 2회지에서는 많이 발견되지 않았던 Mucoromycota (41,490 read, 13.9%), Agaricales (10,586 read, 3.6%)가 높은 비율로 분포를 하고 있었다. 토양소독 처리에 따른 10a 당 수량을 살펴본 결과, 윤작 1,309 kg, 태양열소독 1,609 kg, 토양훈증 1,733 kg으로 나타났고, 수량지수가 윤작 처리구 대비 태양열소독은 23%, 토양훈증은 32% 높았다. 성마율은 윤작 51%, 태양열소독 63%, 토양훈증 68%으로 나타났으며, 자마율은 윤작 49%, 태양열소독 37%, 토양훈증 32%으로 나타났다. 괴경썩음 정도는 윤작 30-49%, 태양열소독 10-19%, 토양훈증 5-9%로 나타났다. 따라서, 비가림시설을 활용한 천마 재배 시 토양훈증 소독 처리를 하면 연작이 가능할 것으로 판단되었다.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.8
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• pp.542-548
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• 2014

Effects of bromide ($Br^-$) and iodide ($I^-$) concentrations, chlorine ($Cl_2$) doses, pH, temperature, ammonia nitrogen concentrations, reaction times and water characteristics on formation of iodinated trihalomethanes (I-THMs) during oxidation of iodide containing water with chlorine were investigated in this study. Results showed that the yields of I-THMs increased with the high bromide and iodide level during chlorination. The elevated pH significantly increased the yields of I-THMs during chlorination. The formation of I-THMs was higher at $20^{\circ}C$ than $4^{\circ}C$, $10^{\circ}C$ and $30^{\circ}C$. In chloramination study, addition of ammonium chloride ($NH_4Cl$) markedly increased the formation of I-THMs. Among the water samples collected from seven water sources including wastewater treatment plant (WWTP) effluent water (EfOM water), prepared humic containing water (HA water) and algal organic matter (AOM) containing water (AOM water), EfOM water generated the highest yields of I-THMs ($12.31{\mu}g/mg$ DOC), followed by HA water ($4.96{\mu}g/mg$ DOC), while AOM water produced the lowest yields of I-THMs ($0.99{\mu}g/mg$ DOC). $SUVA_{254}$ values of EfOM water, HA water and AOM water were $1.38L/mg{\cdot}m$, $4.96L/mg{\cdot}m$ and $0.97L/mg{\cdot}m$, respectively. The I-THMs yields had a low correlation with $SUVA_{254}$ values ($r^2$ = 0.002).

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.184-191
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• 2007

Coal-, coconut- and wood-based activated carbons and anthracite were tested for an adsorption and biodegradation performances of nitrogenous chlorinated by-products such as chloropicrin, DCAN, DBAN and TCAN. In early stage of operations, an adsorption performance was a main mechanism for removal of nitrogenous chlorinated by-products, however as increasing populations of attached bacteria, the bacteria played a major role in removing nitrogenous chlorinated by-products in the activated carbon and anthracite biofilter. It was also investigated that the compounds were readily subjected to biodegrade. Whilst the coal- and coconut-based activated carbons were found most effective in adsorption of the compounds, the anthracite was worst in adsorption of the compounds. Highest populations and activity of attached bacteria were shown in the coal-based activated carbon. The populations and activity of attached bacteria decreased in the order: coconut-based activated carbon > wood-based activated carbon > anthracite. The attached bacteria were inhibited for removal of the compounds at temperatures below $10^{\circ}C$. The attached bacteria were more active at higher water temperatures$(20^{\circ}C\;<)$ but less active at love. water temperature$(10^{\circ}C\;>)$. The removal efficiencies of the compounds obtained using coal-, coconut- and wood-based activated carbons and anthracite were directly related to the water temperatures. In particular, water temperature was the most important factor for removal of the compounds in the anthracite biofilter because the removal of the compounds depended mainly on biodegradation. Therefore, the main removal mechanism of the compounds the main mechanism on the removal of the compounds using activated carbon was both adsorption and biodegradation by the attached bacteria. The observation suggests that using coal-based activated carbon is the best for removal of nitrogenous chlorinated by-products in the water treatment.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.347-356
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• 1999

Background: Exit site/tunnel infection causes considerable morbidity and technique failure in CAPD patients. We presently use a unique revision method for the treatment of refractory ESI/TI in CAPD patients and mupirocin prophylaxis for high risk patients. Materials and Methods: We reviewed 139 CAPD patients about the ESI/TI from October 1993 to February 1999 at Yeungnam University Hospital. At the beginning of the ESI. we usually started medications with rifampicin and ciprofloxacin and then changed the antibiotics according to the sensitivity test. If the ESI had persisted and there were TI symptoms (purulent discharge, abscess lesion around exit site). we performed catheter revision(external cuff shaving, disinfection around tunnel and new exit site on opposit direction) with a combination of proper antibiotics. We applied local mupirocin ointment at the exit site three times per week to the 34 patients who had the risk of ESI starting from October 1998. Results: The total follow-up was 2401 patient months(pt. mon). ESI occurred on 105 occasions in 36 out of 139 patients, and peritonitis occurred on 112 occasions in 67 out of 139 patients. The total number of incidences of ESI and peritonitis was 1 per 23.0 pt. mon and 1 per 2l.6 pt.mon. The most common organism responsible for ESI was Staphylococcus aureus (26 of 54 isolated cases, 48%), followed by the Methicillin resistant S. aureus(MRSA) (13 cases, 24%). Seven patients(5: MRSA. 2: Pseudomonas) had to be treated with a revision to control infection. Three patients experienced ESI relapse after revision. One of them improved with antibiotics, while another needed a second revision and the remaining required catheter removal due to persistent MRSA infection with re-insertion at the same time. But, there was no more ESI in these 3 patients who were received management to relapse (The mean duration: 14.0 months). The rates of ESI were significantly reduced after using mupirocin than before(1 per 12.7 vs 34.0 pt.mon, P<0.01). Conclusions: In summary, revision technique can be regarded as an effective method for refractory ESI/TI before catheter removal. Also local mupirocin ointment can play a significant role in the prevention of ESI.

• The Journal of Korean Society for School & Community Health Education
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• v.1 no.2
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• pp.49-71
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• 2000

The purpose of this study was to serve as a basis for school health care of better quality, by making a comparative analysis of the health care satisfaction and attitude of elementary school students in consideration of their general characteristics and the presence or absence of nurse teacher. The subjects in this study were 919 selected six graders in 16 elementary schools in the city of Tongduchun, Koyang and Euijungbu, Yangju-kun and Yeunchun-kun. A survey was conducted with questionnaire designed for measurement of health care satisfaction and attitude. As a result of analyzing the data collected from June 1 through 15, 2000, the conclusions were as follows. 1) As for the general characteristics of the students investigated, the subjects included 513 boys(55.8%) and 406 girls(44.2%). The schools where 390(42.4%) students attended were located in municipal area, and the schools where 529(57.6%) students attended were located in kun area. 608(66.2%) students had a nurse teacher at their schools, while 311(33.8%) students had no nurse teacher. 498(54.2%) had an experience to use the health room this year, but 421(45.8%) had no such an experience. Their mean school life satisfaction was scored $3.42{\pm}.71$, above the average. And their health condition was rated $3.81{\pm}.87$, which implied they tended to be in good health. 2) The mean satisfaction at the health room operation was scored $3.33{\pm}.71$, above the medium level. What they were most satisfied with($4.02{\pm}1.08$) was, among the health room facilities, that there were beds. But they expressed the least satisfaction($2.83{\pm}1.17$) at the location of health room. The presence or absence of nurse teacher made a significant difference to their satisfactionat health room operation, because the students in schools with nurse teacher showed greater satisfaction($3.42{\pm}.72$) than the others in schools with no nurse teacher did($3.15{\pm}.66$). 3) Concerning their attitude to use the health room in case of disease or accident occurrence, a lot of students in schools with a nurse teacher, who had ever suffered from indigestion, headache or traumatic injury, used the health room. In schools with no nurse teacher, there was a tendency to talk to their class teachers(p<.001). The recognition of the necessity for health counseling was generally on a medium level. The counselor whom they wanted to discuss health problem with was family or friend in the largest cases. Few students discussed with class teachers in case there was a nurse teacher in school. Instead, some of them discussed with friend, family or nurse teacher, and there was a significant difference between them(p<.001). 4) The mean satisfaction at health, sanitation and environmental management was rated $3.20{\pm}.90$, above the average. The classroom lighting gave them the best satisfaction with $3.67{\pm}1.07$, but the satisfaction at toilet cleanness and disinfection was not good with $2.83{\pm}1.19$. By the presence or absence of nurse teacher, those who had a nurse teacher expressed better satisfaction at water supply facilities including hot water than the others who had no nurse teacher did(p<.001). But no significant difference was observed in the other items. 5) The health education satisfaction was rated $3.19{\pm}.99$, which was on a medium level. By item, the mean satisfaction level was $3.36{\pm}1.19$ at nurse teacher's explanation about treatment, $3.13{\pm}1.15$ at the frequency of health education, and $3.08{\pm}1.16$ at the explanation on the cause of disease. By the presence or absence of nurse teacher, the students with nurse teacher showed significantly better satisfaction at every factor0(p<.001). 6) Regarding health education attitude, their recognition of the need for school health education was scored $3.89{\pm}.96$. Those who had a nurse teacher felt it more necessary($3.96{\pm}.92$), yet the others who had no nurse teacher felt its necessity a little less($3.74{\pm}1.01$). The most preferred thing for them to learn in health education was first aid, followed by sex education, obesity prevention, safety accident prevention in school and outdoors, smoking-related health, good use of leisure time, and environmental pollution cause in the order named. According to the presence or absence of nurse teacher, there was a significant difference in sex education(p<.01), but no significant disparities were found in the other factors. The most preferred person who would offer health education was a lecturer from the outside(45.8%) and nurse teacher(45.4%). Their preference for class teacher as a person in charge of health education was just 8.8%. But the presence or absence of nurse teacher didn't produce any differences to their preference for a person in charge of health education.

• Analytical Science and Technology
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• v.8 no.1
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• pp.91-99
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• 1995

One of alternative conventional technologies used for treatment of livestock wastes is composting process, and recently some mechanical composting processes are being practiced. It is, however, recognized the composting process also has its own limitations such as longer time requirement, and difficulties to estimate the degree of decomposition, etc. The incomplete compost contains potentially harmful materials to crops and public health due to instabilized organic contents and pathogenic organisms. The purpose of this investigation is to develop an innovative system whereby anxious livestock wastes are thoroughly stabilized and disinfected. Thus the overall management scheme should meet the following requirements. 1. A system should be in a cost-effective and environmentally sound manner. 2. Sludges must be chemically stabilized and bacteriologically safe. 3. Odor-free by product should be applied to crop land. 4. Sludges are sources of fertilizer nutrients and/or soil amendments to enhance crop production. 5. And they can be used as potential pH adjusting agent of the acidified soils. Overall effectiveness of the developed system is experimentally tested to satisfy the preset criteria and requirements. Major experiments are divided into four categories: they are 1. chemical stability test, 2. optimal condition test of stabilization process, 3. bacteriological examination and disinfection tests, and 4. deodorization tests The stabilization process is consisted of the stabilizing reaction process and the drying process. Stabilized wastes is dried by both sun dryer and rotary dryer. It is shown that an additive dosage of about g/kg solid in wastes with a minimum of 5-minutes reaction would be necessary for effective stabilization reaction. The stabilization process is consisted of the stabilizing reaction process and drying process. Stabilized wastes are dried by both sun dryer and rotary dryer. It is shown that an additive dosage of about 300g/kg solid in wastes with a minimum of 5-minutes reaction would be necessary for effective stabilization reaction. In the stabilization reaction process, the pH of wastes is lowered from initial values of 12.3 to 8.6. High pH prevents odor production and kills pathogenic organisms. Organic matter contents in the stabilized wastes are about 50% and the sum of contents of fertilizer elements such as total nitrogen, $P_2O_5$ and $K_2O$ are about 5.3%. The livestock wastes that are stabilized chemically and hygienically can be used as a good soil conditioner and/or organic fertilizer.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.225-236
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• 2005

The protection of public health In wastewater reclamation and reuse is one of the most important issues. Monitoring data of Escherichia coli were collected from paddy rice plots in 2003 and 2004 experiments. Five treatments were used and each one was triplicated to evaluate the changes of E. coli: surface water, biofilter effluent (secondary level), UV-disinfected water and pond treatment. Microbial risk was quantified to assess human health risk by exposure to E. coli in paddy rice plots, which were irrigated with reclaimed wastewater. Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion that may occur to farmer and neighbor children. Monte-Carlo analysis (10,000 trials) was used to estimate the risk characterization of uncertainty. In the following analysis, two scenarios were related to the reduction of risk against direct ingestion and exposure times. Scenarios A and B were assumed that the risk was 1,000 and 10,000 times lower than direct ingestion.'Golfers were assumed to be 0.001 L of reclaimed water by contact with balls and their cloths. Opportunity of contact in paddy rice field with pathogens was more frequent than handing golf balls, because of agricultural activity was practiced in ponded water in paddy rice culture. As a result of microbial risk assessment using total data of experimental period, risk value of E. coli in 2003 and 2004 experiment ranged from $10^{-5}$ to $10^{-8}$ and $10^{-4}$ to $10^{-8}$, respectively. The risk values in biofilter effluent irrigation was the highest, which is $10^{-4}$ in 2003 and $10^{-5}$ in 2004 experiments with scenario A. Ranges of $10^{-6}$ to $10^{-8}$ were considered at reasonable levels of risk for communicable disease transmission from environmental exposure and the risk value above $10^{-4}$ was considered to be attributable to the risk of infection. Irrigation with UV-disinfected water in the paddy field during the agricultural Period showed significantly lower microbial risk than others, and their levels of risk value were within the range of actual paddy rice field with surface water.