• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.903-909
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• 2023

The purpose of this study is to compare and analyze the effect of changes in the patient's central position on the exposure dose and image quality of surrounding organs during a chest lateral examination using an Auto Exposure Control(AEC). The experiment was conducted on a human body phantom. A needle was attached to the lower part of the center of the coronal plane of the phantom, and a lead ruler was attached to the lower part of the detector so that the 50 cm point was located at the lower center of the AEC ion chamber. The exposure conditions were 125 kVp, 320 mA, the distance between the source and the image receptor was 180 cm, and the exposure field size was 14 × 17 inches. Only one AEC ion chamber was used at the bottom center, and the density was set to '0' and sensitivity to 'Middle', and the central X-ray was incident vertically toward the 6th thoracic vertebra. With AEC mode applied, the 50 cm point of the needle and lead ruler were aligned and the phantom was moved 5 cm toward the stomach (F5) and 5 cm toward the back (B5), and the dose factor was analyzed by measuring ESD. The ESD of the thyroid gland according to the change in patient center position was 232.60±2.20 μGy for Center, 231.22±1.53 μGy for F5, and 184.37±1.19 μGy for B5, and the ESD of the breast was 288.54±3.03 μGy for Center, F5 was 260.97±1.93 μGy, B5 was 229.80±1.62 μGy, and the ESD of the center of the lung was 337.02±3.25 μGy for Center, F5 was 336.09±2.29 μGy, and B5 was 261.76±1.68 μGy. As a result of comparing the average values of dose factors between each group, the difference in average values was statistically significant (p<0.01), and each group appeared to be independent. As a result of the study, there was no significant difference in the dose to the thyroid, breast, and center of the lung according to the change in the patient's central position, except for the breast (10%) when the patient moved forward about 5 cm. However, movement of about 5 cm posteriorly resulted in an average dose reduction of 23.7%. Additionally, when the patient's central position was moved to the rear, image quality deteriorated.

• Korean Journal of Culture and Social Issue
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• v.12 no.5_spc
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• pp.133-147
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• 2006

Korean society is rapidly becoming an ageing society. The Korean may have to live longer than did their parents. Increasing life expectancy and changing social structure, Korean people are getting interested in quality of life, and well-being is becoming a matter of concern. And, the Korean is fully aware of the importance of health for well-being or good life. This concern about health may bring about specific behaviors related to health. Although health care expenditures of Korea are currently smaller than those of other developed countries, it is continuously increasing. Large portion of increased amount of health care expenditures is to spend for disease prevention and expansion of long-term care facilities. Constructs of well-being of the Korean, not living in western culture, may be different from those of people living in western society. Health is not top-ranked to importance for quality of life in previous studies. It does not mean health isn't determinant factor for good life or well-being. Health is an essential element for well-being. It has been proved in several researches which examined poor quality of life caused by certain diseases and management of health-related quality of life. Some theories relate to health-seeking behaviors suggested the health belief or the attitude toward health, intention to do health behavior, perceived behavioral control, and self efficacy as important factors which could predict health-related behaviors. With getting older, people decline in physical and physiological functions and become vulnerable to chronic diseases. Quality of life depends on how to adjust to these changes in senescence. Social supports, especially supports from offspring, are very important to quality of life in senescence, because supports from offspring have influence on pride of the older, they may be afraid of disclose the conflict with their offspring. Avoiding self-disclosure exclude other source of social supports and harm individual's health, therefore psychological intervention is needed to. Increasing life expectancy of the Korean, Korean government has to provide numerous long-term care facilities as well as psychosocial supports. The Korean, so far, does not recognize that psychologist could render great service to promoting individual or community health and improving individual's quality of life. It is highly expected that psychologists take actively interested and involve in health related to quality of life.

• Economic and Environmental Geology
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• v.57 no.3
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• pp.281-292
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• 2024

North Korea relies heavily on coal as the primary energy source, playing an important role in all energy demand sectors except for the transportation sector. Approximately half of the total electricity is generated through coal-fired power plants, and coal is used to produce heat and power for all industrial facilities. Furthermore, coal has been a significant contributor to earning foreign currency through long-term exports to China. Nevertheless, since the 1980s, indiscriminate mining activities have led to rapid depletion of coal production in most coal mines. Aging mine facilities, lack of investment in new equipment, shortages of fuel and electricity, difficulties in material supply, and frequent damage from flooding have collectively contributed to a noticeable decline in coal production since the late 1980s. North Korea's coal deposits are distributed in various geological formations from the Proterozoic to the Cenozoic, but the most critical coal-bearing formations are Ripsok and Sadong formations distributed in the Pyeongnam Basin of the Late Paleozoic from Carboniferous to Permian, which are called as Pyeongnam North and South Coal Fields. Over 90% of North Korea's coal is produced in these coal fields. The classification of coal in North Korea differs from the international classification based on coalification (peat, lignite, sub-bituminous coal, bituminous coal, and anthracite). North Korean classification based on industrial aspect is classified into bituminous coal, anthracite, and low-grade coal (Chomuyeontan). Based on the energy factor, it is classified into high-calorie coal, medium calorie coal, and low-calorie coal. In North Korea, the term "Chomuyeontan" refers to a type of coal that is not classified globally and is unique to North Korea. It is a low-grade coal exclusively used in North Korea and is not found or used in any other country worldwide. This article compares North Korea's coal classification and the international coal classification of coal and provides insights into the geological characteristics, reserves, utilization, and research trends of North Korean coal resources. This study could serve as a guide for preparing scientific and industrial agendas related to coal collaboration between North Korea and South Korea.

• Journal of Korean Society of Forest Science
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• v.113 no.3
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• pp.282-291
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• 2024

In Korea, pine forests are continuously declining as they mature. Along with vegetation succession, mushroom succession also occurs. The productivity of pine mushroom, a mycorrhizal species that was introduced as a source of short-term forest income in the late 20th century, is also declining. Although the forest fires was originally blamed as the main cause of pine forests decline, it has not been identified as a significant factor in the decline of pine mushroom productivity. Pine mushrooms are mainly produced in pine-dominant stands ranging in age classes from 3 to 8, with the highest productivity occurring between 4 and 6 classes. Accordingly, the aging of pine forests and their succession to mixed forests were evaluated as the most important factors contributing to the decrease in pine mushroom productivity. Since tending practices in pine mushroom-producing forests contribute to maintaining and increasing the productivity of pine mushrooms in mature pine forests, production can be sustained through proactive forest/soil management. In recent years, attempts have been made to cultivate pine mushrooms. The method of producing a mycorrhizae-infected pine tree by planting a pine in front of a fairy ring of Tricholoma matsutake and then transplanting it to create a new pine mushroom-producing stand has been successful. However, the method may cause damage to the fairy ring and has difficulties to preserve the viability of mycorrhizal fungus during transplantation. Mycorrhizae-inoculated seedling production is proposed as an alternative technology, but difficulties remain in keeping the fungus in the seedling during transplantation. Research on the microbiome of the fairy ring of T. matsutake is being conducted to solve this problem. Bacteria and fungi that contribute to the mycelial growth of T. matsutake have been discovered. It is expected that the era of industrial cultivation of pine mushroom will soon be possible through a microbial ecological approach.

• Journal of the Korean Society of School Health
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• v.2 no.1
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• pp.58-90
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• 1989

This study was attempted to contribute to the development of school health by providing the basic data about the distribution basis and distribution aspect of teachers holding additional school health that are in charge of school health business in parimary schools, middle schools and high schools without any nurse-teacher. This study analyzed literatures about the history, related laws, organization and professional manpower of school health. The emphasis was set on the distribution basis of theachers holding additional school health. The results of this study are as following: 1. The school health of the world dates to the late 18th century in Europe where was free supplying with food for poor children. The school health of Korea orginated from smallpox vaccination which was executed with appearance of modern schools in the late 19th century. 2. The related laws of school health began as a part of Education Law with was constituted in 1949. By the School Health Law constituted in 1967 and the enforcement ordinance of School Health made firm the legal basis of school health. 3. The administrative organs of school health are the Ministry of Education in center and each Board of Education in cities and provinces. For the first time in 1979, the department of school health was established in the organization of the Ministry of Education. And at about the same time of establishment of the department of school health, health section was established in the department of social physical-training in locality. 4. In the manpower of school health which was presented in the related statute of school health, there are the ward chief of education, the superintendent of educational affair, of cities and districts, the mayors, the governors of provinces, the school managers, the principals, the school doctors, the school pharmacists, and the nurse-teachers, including teachers holding additional school health as the practical manpower of school health. 5. In order to get some information on distribution aspect of teachers additional school health, this study made up a questionnaire from August 3 to August 11, 1988. The subjects of this study were 212 leachers who took part in the yearly training for teachers holding additional school health from Kyunggi province, Chungbuk province and Jeonbuk province. The results of the questionnaire are as following: 1. The distribution percentages of teachers holding additional school health according to each Board of Education wich schools are subject to, are as following:70.1% (Kyunggi), 76.5% (Chungbuk), and 81.4% (Jeonbuk). There was a significant difference. The distribution percentages of teachers holding additional school health according to the school levels of 3 provinces are as following: 74.1% (Primary schools), 77.8% (Middle schools), 76.7% (High schools). There were little significant differences. 2. The distribution according to the general characteristics of the subject schools: There were 64.2 percent of primary schools and 35.8 percent of middle schools among 212 schools. 91. 5 percent of schools were located in districts. Public schools formed 55.7% and then national schools were higher in percentage than private schools. 58.5 percent of schools had 1-9 classes, 64.6 percent of schools had 101-500 students, and 90 percents of schools had 1-20 teachers. In considering student sex, the coed school showed the high distribution percentage (Primary schools : 100%, Middle schools: 81.6%). 3. The distribution according to the characteristics of teachers holding additional school health: 93.3 percent of teachers were female, and more than 60 percent of teachers were 20-29 years old. As the age got higher, the percentage became lower. There were little significant differences by marital status. In considering their educational status, 86.8 percent of teachers in primary schools were from teacher's colleges, and 64.5 percent of teachers in middle schools were from education colleges. In considering teaching career, 46.7 percent of teachers had teaching career of less than 2 years. 73.6 percent of teachers had held additional school health for less than one year. More than 80 percent of teachers had participated in the training one time or twice. More than 70 percent of teachers had 1-2 additional jobs except for the school health business. The motivation to hold additional school health is most caused by mandatory order, which accounts for more than 80.0 percent. In considering interesting degree concerning school health, lukewarm answer is the highest of 62.7 percent, followed by affirmative answer of 23.6 percent. In considering their contentment degree respecting additional school health job, "discontent or very discontent"is the highest of 47.6 percent. As a descontent reason of additional school health job, overwork is the highest factor of 37.9 percent. Among addiitional school health job, the most difficult affair is nursing service to be 34.0 percent, followed by health education of 31.6 percent. It testify the need of professional. The source of knowledge about school health has been acquired from masscommunication or private health experience, which account for as much as 56.1 percent. It shows seriousness of lack of professionalism. With regard to neccessity of school health experts, 95.8 percent represents absolute need. With above consideration of study results, I propose as follows : 1. I propose that the authorities concerned unify and improve statute respecting current school health which has not been steadfastly supporting school health business by ambiguity of expression and dualization. 2. I propose that the authorities concerned give the school manager, school staffs and parents of students educational chance with which they can acknowledge the importance of school health and in which they can participate as well as set up alternative policy plan to be albe to vitalize school health committee. 3. I propose that administrative organization practicable to taking totally charge of school health business is established within the Ministry of Education. 4. I propose that the authorities concerned back up and cooperate in an attempt by make school health better and desirable toward development by way of appointing qualitied health teachers on the basis of legally regular teacher staffs.

• Journal of Haehwa Medicine
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• v.8 no.2
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• pp.211-243
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• 2000

This study was performed to investigate the cause, symptom, treatment, medicine of Wei symptom through the literature of oriental and western medicine. The results obtained were as follows: 1. Wei symptom is the symptom that reveals muscle relaxation without contraction and muscle relaxation occures in the lower limb or upper limb, in severe case, leads to death. 2. Since the pathology and etiology of Wei symptom was first described as "pe-yeol-yeop-cho"(肺熱葉焦) in Hung Ti Nei Ching(黃帝內經), for generations most doctors had have accepted it. but after Dan Ge(丹溪), it had been classified into seven causes, damp-heat(濕熱), phlegm-damp(濕痰), deficiency of qi(氣虛), deficiency of blood(血虛), deficiency of yin(陰處), stagnant blood(死血), stagnant food(食積). Chang Gyeng Ag(張景岳) added the cause of deficiency of source qi(元氣). 3. The concept of "To treat Yangming, most of all"(獨治陽明) was emphasized in the treatment of Wei symptom and contains nourishment of middle warmer energy(補益中氣), clearance of yangming-damp-heat(淸化陽明濕熱). 4. Since Nei-ching era(內經時代), Wei and Bi symptom(痺症) is differenciated according to the existence of pain. After Ming era(明代) appeared theory of co-existence of Wei symptom and pain or numbness but they were accepted as a sign of Wei symptom caused by the pathological factor phelgm(痰), damp(濕), stagnancy(瘀). 5. In the western medical point of view, Wei symptom is like paraplegia, or tetraplegia. and according to the causative disease, it is accompanied by dysesthesia, paresthsia, pain. thus it is more recommended to use hwal-hyel-hwa-ae(活血化瘀) method considering damp-heat(濕熱), qi deficiency of spleen and stornach(脾胃氣虛) as pathological basis than to simply differenciate Wei and Bi symptom according to the existence of pain. 6. The cause of Gullian-Barre syndrome(GBS) is consist of two factors, internal and external. Internal factors include asthenia of spleen and stomach, and of liver and kidney. External factors include summur-damp(暑濕), damp-heat(濕熱), cold-damp(寒濕) and on the basis of "classification and treatment according to the symptom of Zang-Fu"(臟腑辨證論治), the cause of GBS is classified into injury of body fluid by lung heat(肺熱傷津), infiltration of damp-heat(濕熱浸淫), asthenia of spleen and kidney(脾腎兩虛), asthenia of spleen and stomach(脾胃虛弱), asthenia of liver and kidney (肝腎兩虛). 7. The cause of GBS is divided by according to the disease developing stage: Early stage include dryness-heat(燥熱), damp(濕邪), phlegm(痰濁), stagnant blood(瘀血), and major treatment is reducing of excess(瀉實). Late stage include deficiency of essence(精虛), deficiency with excess(虛中挾實), and essencial deficiency of liver and kidney(肝腎精不足) is major point of treatment. 8. Following is the herbal medicine of GBS according to the stage. In case of summur-damp(暑濕), chung-seu-iki-tang(淸暑益氣湯) is used which helps cooling and drainage of summer-damp(淸利暑濕), reinforcement of qi and passage of collateral channels(補氣通絡). In case of damp-heat, used kun-bo-hwan(健步丸), In case of cool-damp(寒濕), used 'Mahwang-buja-sesin-tang with sam-chul-tang'(麻黃附子細辛湯合蓼朮湯). In case of asthenia of spleen and kidney, used 'Sam-lyeng-baik-chul san'(蔘笭白朮散), In case of asthenia of liver and kidney, used 'Hojam-hwan'(虎潛丸). 9. Following is the herbal medicine of GBS according to the "classification and treatment according to the symptom of Zang-Fu"(臟腑辨證論治). In the case of injury of body fluid by lung heat(肺熱傷津), 'Chung-jo-gu-pae-tang'(淸燥救肺湯) is used. In case of 'infiltration of damp-heat'(濕熱浸淫), us-ed 'Yi-myo-hwan'(二妙丸), In case of 'infiltration of cool-damp'(寒濕浸淫), us-ed 'Yui-lyung-tang', In case of asthenia of spleen, used 'Sam-lyung-bak-chul-san'. In case of yin-deficiency of liver and kidney(肝腎陰虛), used 'Ji-bak-ji-hwang-hwan'(知柏地黃丸), or 'Ho-jam-hwan'(虎潛丸). 10. Cervical spondylosis with myelopathy is occuered by compression or ischemia of spinal cord. 11. The cause of cervical spondylosis with myelopathy consist of 'flow disturbance of the channel points of tai-yang'(太陽經兪不利), 'stagnancy of cool-damp'(寒濕凝聚), 'congestion of phlegm-damp stagnant substances'(痰濕膠阻), 'impairment of liver and kidney'(肝腎虛損). 12. In treatment of cervical spondylosis with myelopathy, are used 'Ge-ji-ga-gal-geun-tang-gagam'(桂枝加葛根湯加減), 'So-hwal-lack-dan-hap-do-hong-eum-gagam(小活絡丹合桃紅飮加減), 'Sin-tong-chuck-ue-tang-gagam(身痛逐瘀湯加減), 'Do-dam-tang-hap-sa-mul-tang-gagam'(導痰湯合四物湯加減), 'Ik-sin-yang-hyel-guen-bo-tang'(益腎養血健步湯加減), 'Nok-gakyo-hwan-gagam'(鹿角膠丸加減). 13. The cause of muscle dystropy is related with 'the impairement of vital qi'(元氣損傷), and 'impairement of five Zang organ'(五臟敗傷). Symptoms and signs are classified into asthenia of spleen and stomach, deficiency with excess, 'deficiency of liver and kidney'(肝腎不足) infiltration of damp-heat, 'deficiency of qi and blood'(氣血兩虛), 'yang deficiency of spleen and kidney'(脾腎陽虛). 14. 'Bo-jung-ik-gi-tang'(補中益氣湯), 'Gum-gang-hwan'(金剛丸), 'Yi-gong-san-hap-sam-myo-hwan'(異功散合三妙丸), 'Ja-hyel-yang-gun-tang'(滋血養筋湯), 'Ho-jam-hwan'(虎潛丸) are used for muscle dystropy. 15. The causes of myasthenia gravis are classified into 'insufficiency of middle warmer energy'(中氣不足), 'deficiency of qi and yin of spleen and kidney'(脾腎兩處), 'asthenia of qi of spleen'(脾氣虛弱), 'deficiency of qi and blood'(氣血兩虛), 'yang deficiency of spleen and kidney'(脾腎陽虛). 16. 'Bo-jung-ik-gi-tang-gagam'(補中益氣湯加減), 'Sa-gun-ja-tang-hap-gi-guk-yang-hyel-tang'(四君子湯合杞菊地黃湯), 'Sa-gun-ja-tang-hap-u-gyi-eum-gagam'(四君子湯合右歸飮加減), 'Pal-jin-tang'(八珍湯), 'U-gyi-eum'(右歸飮) are used for myasthenia gravis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1561-1579
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• 1969

In Korea, the duty of water in paddy fields was measured at the Agricultural Experimental Station in Suwon about 60 years ago. After that time some testing has been made in several places, but the key points in its experiment were the water depth of evapo-transpiration. Improved breeds, progress in cultivation and management techniques as well as development of measuring apparatus in recent years have necessitated the review of the duty of water in paddy fields. The necessity of reviewing the conventional methods has become even more important, as no source of information has been made available through survey of water utilization on a soil use basis which requires data on peculiar features of the water depth of evapo-transpiration. For example, the duty of water in paddy field is largely affected by the water depth of evapo-transpiration in connection with the wetted paddy field, whereas in connection with the normal paddy fields without this characteristic the vertical percolation become the predominant factor in measuring the decreasing depth of water. Therefore, it becomes important. that not only the water depth of evapotranspiration but also the vertical percolation process should also be observed in order to arrive at a realistic conclusion. As the vertical percolation has aclose relationship to the height of the underground water, the change of the latter can be measured. As the conclusion of this experiment, the following subjects are indicated. 1. In order to determine the economic duty of water in paddy fields on a basis of varying soil features, the varying soil features in the benifited area should be investigated thoroughly. The water depths of evapo-transpiration(ET) ratio to evaporation in the evaporator(V) on a basis of the varying soil features are as follows: clay loam ET/V = 1.11, loam ET/V = 1.64, sandy loam ET.V = 1.63 2. The decreasing depth of water consists of the water depth of evapotranspiration, the vertical per colation and the percolation of foot path. Among these three, the percolation of foot path can be utilized again. 3. As the result of this experiment, it shows the decreasing depth of water as follows. clay loam 9.3 mm/day, loam 13.5mm/daty, sandy loam 15.3mm/day 4. On a basis of the varying soil features and the height of the underground water, the vertical percolation varies. 5. The change of the vertical percolation on a basis of the varying soil features shows as follows: clay loam $1{\sim}2$ mm/day, loam $2{\sim}3$mm/day, sandy loam $3{\sim}4$mm/day 6. The level of the underground water changes sensibly by priority of clay loam, loam, sandy loam. When it rains, the level of the underground water rises fast and falls down slowly. 7. The level of the underground water changes within the scope of 25cm 8. The transpiration ratio is given in table 8 and their value are as follows: clay loam 168.8, loam 255.6, sandy loam 272.5

• Clinical and Experimental Reproductive Medicine
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• v.34 no.1
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• pp.41-48
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• 2007

Objective: To determine whether the presence of Y-chromosome microdeletion affects the outcome of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) program. Methods: Fourteen couples with microdeletion in azoospermic factor (AZF)c region who attempted IVF/ICSI or cryopreserved and thawed embryo transfer cycles were enrolled. All of the men showed severe oligoasthenoteratoazoospermia (OATS) or azoospermia. As a control, 12 couples with OATS or azoospermia and having normal Y-chromosome were included. Both groups were divided into two subgroups by sperm source used in ICSI such as those who underwent testicular sperm extraction (TESE) and those used ejaculate sperm. We retrospectively analyzed our database in respect to the IVF outcomes. The outcome measures were mean number of good quality embryos, fertilization rates, implantation rates, $\beta$-hCG positive rates, early pregnancy loss and live birth rates. Results: Mean number of good quality embryos, implantation rates, $\beta$-hCG positive rates, early pregnancy loss rates and live birth rates were not significantly different between Y-chromosome microdeletion and control groups. But, fertilization rates in the Y-chromosome microdeletion group (61.1%) was significantly lower than that of control group (79.8%, p=0.003). Also, the subgroup underwent TESE and having AZFc microdeletion showed significantly lower fertilization rates (52.9%) than the subgroup underwent TESE and having normal Y-chromosome (79.5%, p=0.008). Otherwise, in the subgroups used ejaculate sperm, fertilization rates were showed tendency toward lower in couples having Y-chromosome microdeletion than couples with normal Y-chromosome. (65.5% versus 79.9%, p=0.082). But, there was no significance statistically. Conclusions: In IVF/ICSI cycles using TESE sperm, presence of V-chromosome microdeletion may adversely affect to fertilization ability of injected sperm. But, in cases of ejaculate sperm available for ICSI, IVF outcome was not affected by presence of Y-chromosome AZFc microdeletion. However, more larger scaled prospective study was needed to support our results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.6
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• pp.511-522
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• 1984

The Nagdong is one of the biggest rivers in Korea, which is very important water source not only for tap water of Pusan city but also for the industrial water. Therefore, authors tried to check the water quality year by year. In this experiment one hundred and twenty water samples collected from August 1983 to July 1984 were analyzed bacteriologically and physiologically. Fifteen sampling stations were established between near Samrangjin and estuary of the river. To evaluate the water quality, temperature, pH, chloride ion, salinity, chemical oxygen demand (COD), electrical conductivity, nutrients, total coliform, fecal coliform, fecal streptococcus, viable cell count and bacterial flora were observed. The variation of water temperature was ranged $-1.5{\sim}29.0^{\circ}C$ (Mean value $13.9{\sim}16.5^{\circ}C$), it in spring was higher as $10{\sim}15^{\circ}C$ about $10^{\circ}C$ than in winter and it in autumm was very stabilized as about $20^{\circ}C$ at each station. The pH variation of the samples was ranged $6.68{\sim}9.15$. The range of concentration of chloride ion and salinity varied $7.4{\sim}l,020.5$ mg/l and $1.05{\sim}33.0\%0$, respectively. Especially, salinity of the 3rd water war was the higher than others as $25.76{\sim}31.58\%0$. COD was ranged $1.45{\sim}14.94$ mg/l and the lower part of the Nagdong River was heavily contaminated by domesitc sewage and waste water from the adjacent factor area. The range of electrical conductivity was $1.360{\times}10^2{\sim}5.650{\times}10^4{\mu}{\mho}/cm$ and that was by far higher the estuary than the upper. Concentration of nutrients were $0.008{\sim}0.040$ mg/l (Mean value $0.019{\sim}0.068$ mg/l) for $NO_2-N,\;0.038{\sim}5.253$ mg/l ($0.351{\sim}2.347$ mg/l) for $NO_3-N,\;0.100{\sim}2.685$ mg/l($0.117{\sim}1.380$ mg/l) for $NH_4-N,\;0.003{\sim}0.084$ mg/l($0.014{\sim}0.065$ mg/l) for $PO_4-P$ and $0.154{\sim}6.123$ mg/l ($1.165{\sim}3.972$ mg/l) for $SiO_2-Si$, respectively. Usually nutrients contents of the water in the upper part(included station 1 to 5) were higher than those of the estuarine area. The bacterial density of the samples ranged 7.3 to 460,000/100 ml for total coliforms, 3.6 to 460,000/100 ml for fecal coliform, $0{\sim}46,000/100ml$ for fecal streptococcus and $<30{\sim}1.2{\times}10^5/ml$ for viable cell count. Composition of coliform was $28\%$ Escherichia coli group, $18\%$ Citrobacter freundii group, $31\%$ Enterobacter aerogenes group and $22\%$ others. Predominant species among the 659 strains isolated from the samples were Pseudomonas spp. ($42\%$), Flavobacterium spp. ($20\%$) and Moraxella spp. ($12\%$).

• Tuberculosis and Respiratory Diseases
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• v.41 no.4
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• pp.379-388
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• 1994

Background : In sleep apnea syndrome, arterial oxygen saturation($SaO_2$) decreases at a variable rate and to a variable degree for a given apneic period from patient to patient, and various kinds of cardiac arrythmia are known to occur. Factors supposed to affect arterial oxygen desaturation during apnea are duration of apnea, lung voulume at which apnea occurs, and oxygen consumption rate of the subject. The lung serves as preferential oxygen source during apnea, and there have been many reports related with the influence of lung volume on $SaO_2$ during apnea, but there are few, if any, studies about the influence of oxygen consumption rate of an individual on $SaO_2$ during breath holding or about the profile of arterial oxygen resaturation after breathing resumed. Methods : To investigate the changes of $SaO_2$ and heart rate(HR) during breath holding(BH) and rebreathing(RB) and to evaluate the physiologic factors responsible for the changes, lung volume measurements, and arterial blood gas analyses were performed in 17 healthy subjects. Nasal airflow by thermistor, $SaO_2$ by pulse oxymeter and ECG tracing were recorded on Polygraph(TA 4000, Gould, U.S.A.) during voluntary BH & RB at total lung capacity(TLC), at functional residual capacity(FRC) and at residual volume(RV), respectively, for the study subjects. Each subject's basal metabolic rate(BMR) was assumed on Harris-Benedict equation. Results: The time needed for $SaO_2$ to drop 2% from the basal level during breath holding(T2%) were $70.1{\pm}14.2$ sec(mean${\pm}$standard deviation) at TLC, $44.0{\pm}11.6$ sec at FRC, and $33.2{\pm}11.1$ sec at RV(TLC vs. FRC, p<0.05; FRC vs. RV, p<0.05). On rebreathing after $SaO_2$ decreased 2%, further decrement in $SaO_2$ was observed and it was significantly greater at RV($4.3{\pm}2.1%$) than at TLC($1.4{\pm}1.0%$)(p<0.05) or at FRC($1.9{\pm}1.4%$)(p<0.05). The time required for $SaO_2$ to return to the basal level after RB(Tr) at TLC was not significantly different from those at FRC or at RV. T2% had no significant correlation either with lung volumes or with BMR respectively. On the other hand, T2% had significant correlation with TLC/BMR(r=0.693, p<0.01) and FRC/BMR (r=0.615, p<0.025) but not with RV/BMR(r=0.227, p>0.05). The differences between maximal and minimal HR(${\Delta}HR$) during the BH-RB manuever were $27.5{\pm}9.2/min$ at TLC, $26.4{\pm}14.0/min$ at RV, and $19.1{\pm}6.0/min$ at FRC which was significantly smaller than those at TLC(p<0.05) or at RV(p<0.05). The mean difference of 5 p-p intervals before and after RB were $0.8{\pm}0.10$ sec and $0.72{\pm}0.09$ sec at TLC(p<0.001), $0.82{\pm}0.11$ sec and $0.73{\pm}0.09$ sec at FRC(p<0.025), and $0.77{\pm}0.09$ sec and $0.72{\pm}0.09$ sec at RV(p<0.05). Conclusion Healthy subjects showed arterial desaturation of various rates and extent during breath holding at different lung volumes. When breath held at lung volume greater than FRC, the rate of arterial desaturation significantly correlated with lung volume/basal metabolic rate, but when breath held at RV, the rate of arterial desaturation did not correlate linearly with RV/BMR. Sinus arrythmias occurred during breath holding and rebreathing manuever irrespective of the size of the lung volume at which breath holding started, and the amount of change was smallest when breath held at FRC and the change in vagal tone induced by alteration in respiratory movement might be the major responsible factor for the sinus arrythmia.