• Title/Summary/Keyword: Physical stress

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A Study on the Investigation into Dental Hygienists' Awareness of Health Impairment Factors by Occupational Diseases (치과위생사의 직업병에 의한 건강장애요인 인식도 조사)

  • Yoon, Mi-Sook;Song, Gui-Sook;Ko, Mi-Hee
    • Journal of dental hygiene science
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    • v.3 no.2
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    • pp.59-66
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    • 2003
  • As a basic research material to make more efficient healthcare and health promotion for dental hygienists, this study intends to determine which factors may affect their awareness of occupational diseases. For this sake, this study attempted to investigate into a variety of literatures and data, and applied a questionnaire survey to 160 dental hygienists for about 5 months(from June to October 2003), who were all employed in domestic dental clinics or offices. As a result of analysis, this study can be concluded as follows: (1) The result of analyzing how dental hygienists recognized their occupational diseases showed that 'stiffness in muscle, neck or shoulder due to intensive use of specific physical regions' and 'stress resulting from the attributes of each task' reached the highest awareness(90.6%) of all, which was followed by 'lower eyesight due to detailed or even sophisticated tasks for many hours(65%)' and 'symptoms of ruptured disk due to standing tasks as dental hygienists do for many hours(62.5%).' (2) The result of analyzing how dental hygienists recognize their occupational diseases showed that their awareness averaged 7.28 points out of 14 points, which implies that their awareness of occupational diseases is not very high. Meanwhile, the result of examining how they recognize detrimental or harmful properties of given materials against human body showed that a majority of total respondents(74.4%) regarded given materials as detrimental to human body. (3) The result of examining how dental hygienists recognize their occupational diseases showed that a majority of total respondents(91.9%) identified their own occupational diseases. Many of total respondents(41.9%) pointed out that environmental improvement around workshop in each clinic or office should be foremost prerequisite to health and welfare for dental hygienists. Next, 34.4% of total respondents pointed out the necessity to perform in-house health diagnosis and examination on a regular basis, and 13.1% of total respondents thought it necessary to carry on healthcare education into harmful properties in the aspect of dental materiology, respectively.

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Etiologic Survey on the Acute Diarrhea of Puppies in Seoul (서울지역에서 문제되고 있는 강아지의 급성설사증에 관한 병인학적 연구)

  • Han Hong-Ryul;Park Hee-Myung;Lee Jin-Hee;Oh Tae-Ho;Jeong Soon-Wuk;Youn Sin-Keun;Park Cheol-Man
    • Journal of Veterinary Clinics
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    • v.10 no.2
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    • pp.171-184
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    • 1993
  • In Seoul area, there are so many kennel clubs, veterinary hospital, pet establishment and breeding confers that various problems have occurred. They are crowed pet houses, poor sanitation, stress to puppies, sudden environmental changes to puppies and unvaccination against parvovirus, canine distemper virus, parainfluenza virus, infectious hepatitis caused by Adenovirus type I and Leptospira. Several studies were made to survey the infectious agents involved in acute diarrhea of poppies in Seoul are, such as history taking, physical examination, complete blood count and serum chemistry, histopathological finding, bacterial isolation and identification, and hemagglutination test in feces and hemagglutination inhibition test in serum against parvovirus, respectively. The results obtained are summarized as followed. 1. The percent of PCV (30.5$\pm$5.6) and concentration of Total protein(5.0$\pm$0.8) resulted from statistical analysis are significantly lower than normal values (p<0.05), respectively. In addition, fibrinogen (505$\pm$326) was significantly higher an normal value (p<0.001), Band neutrophil (22.9$\pm$12.7) showed signifiant difference (P<0.01). decreased monocyte (3.2$\pm$2.1) and eosinophil (0.7$\pm$0.8) values appeared statistically significant (p<0.001), lymphocyte (16.7$\pm$9), as well. 2. The concentrations of calcium .(8.0$\pm$2.8), glucose (40.1$\pm$31.4), and albumin (2.0$\pm$0.39) were lower than normal values (p<0.01, p<0.01, p<0.001), respectively. Also Inorganic phosphate (7.1$\pm$2.4), pH (p<7.9f:0.2), and Blood Urea Nitrogen (40.41=37.1) were significantly higher than normal values (p<0.001, p(0.001, p<0.05), respectively. 3. Simple and mixed infections occupied 18% and 82% in the distribution of causes in puppies with acute diarrhea, respectively. 4. As puppies got older, incidence of acute diarrhea caused by Staphylococcus aureus was decreased to 13% and infection of canine distemper virus was increased to 53%, but E coli and canine parvovirus always showed high frequency of outbreak in the body weight ranged from 35g to 7.8Kg. 5. As showed in table 5, infections of E coli and Canine Parvovirus showed high outbreak regardless of the age which is classified into three stages, 35~50 day, 60 day and 75~day to 1 year, canine distemper virus appeared increased, but in case of Staphylococcus aureus, visa versa. 6. In comparison wi methods for the laboratory diagnosis diagnosis parvovirus, Hemagglutination test showed positive reaction in 25% and mean serum antibody titer measured by Hemagglutination inhibition test showed 2779 (n=20). In addition, positive reaction was 90% (18/20). 7. In histopathological studies, enteritic and pneumonic lesions were indicated in 53.7% and 39.5% of samples, respectively. 8. Etiologic diagnosis based on the history taking, clinical signs and histopathological findings in puppies with acute diarrhea and vomiting indicated that 50% of puppies were infected by canine parvovirus and distemper virus. 9. In the parasitological examination made by simple flotation with saturated zinc sulfate tour parasites found were Isospora canis, Toxocara canis, Ancylostoma spp and Toxocara spp. Isospora canis and Toxocara canis were more frequently found among those parasites of diarrhoeic causes in puppies ranged from 35 days to 1 year. Their infestation rates were 15% and 13% respectively.

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The Effects of Sex Education on the Primary Schooler's Knowledge and Attitude about Sex (성교육이 국민학생의 성지식과 성태도에 미치는 효과)

  • Kim, Jin-Son
    • Women's Health Nursing
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    • v.1 no.2
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    • pp.200-221
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    • 1995
  • The confusion of the sense of value on sex is increasing because of the rapid change in social-cultural environment. Also due to a rise in the standard of living, the age of adolescence is getting lower, and so the second sexual marks appear to primary schoolers. At this time in the aspect of the education for the whole man, it's very important for primary schoolers to acquire right knowledge and desirable attitude on sex so that can overcome psychological instability caused by physical growth, be responsible for their behaviors and lead happy lives. This study was made to find out the effects of sex education for the primary schoolers' knowledge and attitude about sex. The study was designed as simulated control group pretest-posttest design, which only pretest was practiced to control group and after sex education only posttest was practiced to experimental group. The data was collected for 18 days from March 13, 1995 to March 31, 1995. The subjects of this study were 130 six-graders in a private primary school in seoul. The control group and experimental group were composed of 65 pupils, each. Sex education consisted of lecture and discussion and the materials were this researcher's own made, 'How do I grow? and related OHP film and video. This education was practiced 40 minutes at a time, at intervals of 2-4 days' six times during 3weeks. For sex knowledge tools, 20 item questionaries on the base of related reference books and contents of this study were used. For sex attitude tools, this researcher's own made 13 item questionaries were used which were revised and complemented and laying stress on the reference books. The data was analyzed through pc-SAS program. The homogeneity test in terms of the general characteristics of experimental and control group was analyzed through $x^2$-test and t-test. And the difference in the primary schoolers' score on knowledge and attitude about sex before and after the sex education was analyzed through t-test and ANCOVA. The results of this study are as follows : 1. The result of the homogeneity test in terms of the general characteristics of the experimental and control group showed that there were significant differences in economic standard($x^2$=2.92, P=0.052) and brotherly ties($x^2$=3.78, P=0.052). 2. Hypothesis 'After sex education, the score of primary schoolers' sex knowledge will be higher than before. 'showed statistically significant difference.(t=11.99, P=.0001) Sex education was practiced under control over subjective view of economic standard and brotherly ties which showed significant difference at the homogeneity test in terms of the general characteristics between the two groups. After this education, the results of comparing the score of primary schoolers' sex knowledge also showed significant difference between the two groups. So hypothesis I was supported since primary schoolers to have education showed noticeable results in the sex knowledge score. (F=16.52, P=.0001) 3. Hypothesis 'After sex education, primary schooler's sex attitude score will be higher than before' showed statistically significant(t=5.08, P=.0001) Sex education was practiced, too, under control over subjective view of economic standard and brotherly ties which showed significant difference at the homogeneity test in terms of the general characteristics between the two groups. Bat this time the results of comparing the primary schoolers' sex attitude showed no significant difference between the two groups. So hypothesis II was rejected since for primary schoolers to have sex education showed no noticeable results in sex attitude score. (F=3.52, P=.0628) These results of the study show that sex education gives affirmative change to the primary schooler's sex knowledge, bat short periods' sex education doesn't give any change to the sex attitude. For the establishment of the pupils' desirable sex attitude, systematic and concrete sex education fit for the pupils' developing stage should be practiced over a long period of time.

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Comparative Study on Mechanical Properties and Dimensional Stability of Staypak and Wood-Polymer Composites from Populus alba × P. Glandulosa wood (현사시나무로 제조(製造)된 열압축목재(熱壓縮木材)와 목재(木材)-고분자(高分子) 복합체(複合體) 재질(材質)의 비교연구(比較硏究))

  • Pak, Sang-Bum;Ahn, Won-Yung
    • Journal of the Korean Wood Science and Technology
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    • v.13 no.2
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    • pp.14-34
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    • 1985
  • One of the techniques for altering the properties of wood that has received considerable attention in the last twenty years is the formation of a wood-polymer composite (WPC) by irradiation and heat-catalyst polymerization of a monomer incorporated into the wood matrix. Wood-polymer composites are the new products having the superior mechanical and physical properties and the combinated characteristics of wood and plastic. The purpose of this experiment was to obtain the basic data for the improvement of wooden materials by manufacturing WPC and Staypak. The species examined was Hyunsasi-Namoo (Populus alba ${\times}$ P. glandulosa) which had not been utilized yet. Methylmethacrylate (MMA) as monomer, benzoyl peroxide (BPO) as initiator and methyl alcohol as bulking agent were used. The monomer containing BPO was impregnated into wood pieces by the dipping and the vacuum process for 2 hours. After impregnation, the treated samples were polymerized on the hot press with pressure and heat-catalyst methods. The results obtained were summarized as follows 1. The monomer loading into wood by the dipping process was 12.13 percent and 29.99 percent by the vacuum. The polymer loading into wood by the dipping process was 6.79 percent and 15.44 percent by the vacuum. 2. Comparing with Staypak, antishrink efficiency (ASE) of WPC was 12.5 to 13.6 percent on the radial direction and 14.70 to 18.63 percent on the tangential. Antiswelling efficiency (AE) was 14.40 to 17.22 percent on the radial direction and 17.18 to 42.1 8 to 42.14 percent on the tangential. Reduction in water absorptivity (RWA) was 8.19 to 15.5 percent. As a whole, the vacuum process was better than the dipping. 3. The specific gravity of control, Staypak and WPC were 0.44, 0.66 and 0.61 to 0.62, respectively. 4. In the bending strength test, the strength in case that the load direction is on the radial surface was greater than that which the load direction is on the tangential. 5. Increasing rate of stress at proportional limit in compression perpendicular to grain was 72.26 percent in case of WPC by the dipping process, 78.93 percent by the vacuum and 99.09 percent in case of Staypak.

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Inhibitory Effect of Hot-Water Extract of Paeonia japonica on Oxidative Stress and Identification of Its Active Components (백작약 열수추출물의 산화적 스트레스 억제효과 및 유효성분 동정)

  • Jeong, Ill-Yun;Lee, Joo-Sang;Oh, Heon;Jung, U-Hee;Park, Hae-Ran;Jo, Sung-Kee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.5
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    • pp.739-744
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    • 2003
  • This study was carried out to investigate the antioxidative activity and to identify the active components of hot-water extract of Paeoniajaponica (PJ), which was a main ingredient of a herb mixture preparation recently established as a potent candidate of radioprotector in our laboratory. The water extract was fractionated with CHCl$_3$, EtOAc and n-BuOH. The extract and its fractions showed very low activity in hydroxyl radical scavenging test. In lipid peroxidation test, the extract, EtOAc and water fractions showed moderate inhibition with the ratio above 50%. In DPPH radical scavenging test, the extract, EtOAc and water fraction showed high activity with the ratio above 80%, especially. EtOAc fraction scavenged the radicals as much as synthetic antioxidant (BHA), even at low concentration. It is suggested that mai or partition for antioxidative activity of Paeonia japonica was EtOAc fraction. Subsequently, two active compounds (PJE021-1 and JE024-1) from EtOAc fraction were isolated by using MCI gel and silica gel column chromatography The two compounds inhibited remarkedly the $H_2O$$_2$-induced DNA damage in human peripheral blood lymphocytes, measured by single-cell gel electrophoresis (SCGE). PJE021-1 protected the cells to almost negative control level, dose-dependently. PJE024-1 exhibited a potent inhibition with the ratio of 71% at even low concentration (0.5 $\mu\textrm{g}$/$m\ell$). Finally, their chemical structures were identified as gallic acid (PJE021-1) and (+)-catechin (PJE024-1), respectively, on the basis of the speculation of spectral and physical data.

A Study of Home Care Needs of Patients at Discharge and Effects of Home Care -Centered on Patients Discharged from a Rural General Hospilal- (퇴원환자의 가정간호요구와 가정간호사업의 효과 분석 - 일 종합병원을 중심으로)

  • Choi, Yun Soon;Kim, Dai Hyun;Storey, Margaret;Kim, Cho Ja;Kang, Kyu Sook
    • The Korean Nurse
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    • v.31 no.4
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    • pp.77-99
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    • 1992
  • The study was carried out at W. hospital, an affiliated hospital of Y university, involved a total of 163 patients who were discharged from the hospital between May 1990 und March 199J. Data collection was twice, just prior to discharge and a minimum of three months post discharge. Thirty patients who lived within a hour travel time of the hospital received home care during the three months post discharge. Nursing diagnoses and nursing interventions For these patients were analyzed in this study. The results of the study are summarized as follows : 1. Discharge needs for the subjects of the study were analyzed using Gordon's eleven Functional categories and it was found that 48.3% of the total sample had identified nursing needs. Of these, the needs most frequently identified were in the categories of sexuality, 79.3 %, health perception, 68.2 % self concept, 62.5 %, and sleep and rest 62.5 %. Looking ut j he nursing diagnosis that were made for the 30 patients receiving home care, the following diagnoses were the most frequently given; alteration in sexual pattern 79.3%, alterations in health maintenance, 72.6%, alteration in comfort, 68.0%, depression, 64.0%, noncompliance with diet therapy, 6.3.7%, alteration in self concept, 55.6%, and alteration in sleep pattern, 53%. 2. In looking at the effects of home nursing care as demonstrated by changes in the functional categories over the three month period, it was Found that of the 11 functional categories, the need level for health perception, nutrition, activity and self concept decreased slightly over the three month period. On the average sleep patterns improved, but restfulness was slightly less and bowel elimination patterns improved but satisfaction with urinary elimination was slightly less. On the other hand, role enactment, sexuality, stress management and spirituality decreased slightly. The only results that were statistically significant at the 0.05 level were improvement. in digestion and decrease in pain. No statistically significant changes were found in ability related to ADL, the total ADL Score at discharge was $19.78{\pm}8.234, and after 3 months $19.01{\pm}8.12$. Considering that a majority of the patients were over 60 years of age and that many had brain or spinal cord injuries, the fact that their ADL ability did nor deteriorate after discharge can be interpreted as related to a positive impact by the home health care nurses. Similarly there was a slight be not statistically significant decrease in the quality of life scores between the two lest times(l47.83 at discharge and 113.02 at the three month period). Again, when the chronic nature of thee problems facing these patients is considered this maintenance of quality of life can be interpreted as a positive impact by the home health care nurses. 3. One of the home care nursing activities was diagnosis. For this activity it was found that for nine functional health categories(sexuality and spirituality excepted) there were 20 nursing diagnoses. The most frequent were noncompliance, alteration in skin integrity both actual and potential, and impaired physical mobility in that order. 4. Delivery of home health care by the home health nurses included the following nursing activities; assessment, patient education, demonstration of care activities, counselling, direct care to the patient and referrals. Direct care included changing dressings, bladder irrigations, changing Foley catheters, measurement of residual urine, perineal care, position change, back care, oral hygiene, exercise and massage of motion exercises, cleansing enemas, tracheostomy suctioning and tracheostomy care, care of dentures, applications of heat and other similar nursing activities. In conclusion almost 50% of (he sample indicated a need for continued nursing care at the time of discharge and for the patients in the sample who received home care there was a slight decrease in nursing needs but while the patients had chronic and debilitation problems there was ill decrease in ADL abilities or in quality of life. Further study needs Lo be done La increase the reliability and validity of the tool that was used to measure home health care needs. It is also recommended that study by done using a randomized sampling with a control group to compare patients who receive home care with those who do not.

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Disease and Health Behavior of Low-Weight Elderly Living Alone : Focusing on the Community Health Survey 2014 (저체중 독거노인의 질병과 건강행태 : 2014년 지역사회건강조사 자료를 중심으로)

  • Kim, Jong-Im;Kim, Yu-Mi;Nam, Mi-Ra;Choi, Ji-Yeon;Son, Gi-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.479-488
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    • 2018
  • This study was conducted to investigate factors affecting low body weight of solitary elderly people by grasping the illness and health behavior of elderly living alone. Using the raw data of the community health survey from 2014, the data of 922 elderly living alone who are 65 years or older were used for the final analysis. Data were analyzed by technical analysis statistics, The Rao Scott $x^2$ test, and logistic regression analysis using the composite analysis module of the SPSS/WIN 22.0 program. The results of this study showed that elderly living alone had a high percentage of chronic diseases as well as poor health behaviors such as smoking, drinking, lack of exercise, poor eating habits, difficulties in dentistry due to dentures, and poor subjective health status. Result of logistic regression analysis the risk probability of low-weight due to gender of the elderly living alone is as follows. Risk of low body weight because of smoking was 3.004 times among occasional smokers in women and the elderly, while risk of low body weight due to walking amount is less than 3 days the possibility that the person walking is low is 1.420 times significantly higher. When feeling subjective stress, the possibility of low body weight was 2.220 times greater for male elderly and 1.282 times for female elderly. The probability of low body weight for a person with a poor subjective health level was 3.633 times for male elderly and 1.590 times for female elderly. Based on the results of this study, it is necessary to establish appropriate nursing intervention and management strategies to improve health behavior of low body weight elderly living alone. It is also necessary to conduct additional studies considering various variables such as physical, psychological, and social characteristics of low-weight elderly individuals.

A Study on Satisfaction level with Herbal Public Health Services and its Improvement Plans (한방공중보건서비스 만족도와 개선방안)

  • Lee, Jae-Won;Koo, Jin-Suk;Seo, Bu-Il
    • Korean Journal of Oriental Medicine
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    • v.18 no.2
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    • pp.65-89
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    • 2012
  • Objective : In order to investigate and improve public Korean medical health service satisfaction level, this study was designed. Method : A questionnaire has been conducted on 212 patients who received treatments at six public health centers in the northern part of Gyeongbuk during 15 days between Sep. 24 and Oct. 8, 2011. Result : 1. An Investigation on the usage of herbal clinics in public health centers reveals that 63.7% have received three times or more medical treatments previously and 61.8% have had their illness treated at other medical institutions. In regard to illness 32.1% have had arthritis or muscle aches. 50.9% have taken insurance medication after having had treatments at the public health centers. 66% have assessed acupuncture and moxa cautery the most satisfying. 2. To a question regarding whether herbal health treatment costs higher than that of physician's, the highest response at 31.6% is 'No'. And to a question regarding whether herbal medicines administered at public health centers have more side effects than that of physician's, the highest response at 39.6% is 'No'. 3. To a question regarding whether herbal treatment of public health centers has little effect against acute disease, 48.1% of responses are 'Fair'. To a question regarding whether herbal treatments, when compared with physician's treatments, boost better recovery of patients, 48.1% of responses are 'Fair'. To a question regarding whether herbal medicine is unscientific, when compared with that of western medicine, 38.2% of responses are 'Fair', To a question regarding whether herbal medicine has faster effect on disease than western medicine, 41.0% of responses are 'Fair'. To a question regarding whether herbal medicine is more effective on disease prevention and promotion of health than disease treatment, 38.2% of responses are 'Fair'. And to a question regarding whether the lack of various types of physical therapy devices in herbal medicine, when compared with western medicine causes inconvenience in herbal treatment, 42.0% of responses are 'Fair'. Those responses take up highest portion at each questionnaire. 4. A comparative study between herbal treatments and physician's treatments has also been conducted. To questions regarding which one of the two considering types of disease is the better, responses are the latter accounted for 43.9% against 'Cancer', the latter accounted for 45.3% against 'Endocrine disorders', the former accounted for 30.7% against 'Psychiatric disorders', the latter accounted for 38.2% gainst 'Otolaryngological(ENT) disease', the former accounted for 47.6% against 'Post traumatic stress disorder', and the former accounted for 52.4% against 'Muscle-skeletal disease'. 5. An investigation on frequency of patients' visits via (p<0.05) of subjects show a statistically significant difference. 6. First, an investigation on frequency of reasons of medical treatments reveal that age, occupation, monthly income, and insurance type (p<0.05) of subjects show a statistically significant difference. Secondly, an investigation on frequency of subjects taking insurance medicines after herbal health treatments reveal that monthly income (p<0.05) of subject shows a statistically significant difference. 7. First, an investigation on frequency of a claim that herbal treatments of public health center does not have great effect on acute disease reveals that age, education, and insurance type (p<0.05) of subjects show a statistically significant difference. Secondly, an investigation on frequency of analysis that herbal treatments has faster effect on disease compared with western treatments reveals that education level, religion, monthly income, and insurance type (p<0.05) of subjects show a statistically significant difference. 8. When herbal clinics of public health centers and general herbal medicine institutions are compared, a survey on additional treatments that herbal clinics need the most reveals that education level, monthly income, and insurance type (p<0.05) of subjects show a statistically significant difference. Secondly, an investigation on frequency of subjects who want various forms of herbal medicines reveals that occupation and insurance type (p<0.05) of subjects show a statistically significant difference. Conclusion : In order to improve efficiency of treatments and enhance patient's satisfaction level, this study suggests measures such as providing a differentiated acupuncture treatments as a whole, streamlining an reception procedure, adopting more elaborated computer system for a patient to get proper medical attention, standardizing a treatment duration in order for a maximum result, keeping regular office hours, and optimizing a consultation time for a patient.

Chronic Injuries and Types of Injuries Related to Adolescent Taekwondo Athletes (성장기 태권도 선수의 만성 통증과 손상 유형)

  • Kim, Ha-Kyung;Kim, Chang-Yoon;Shim, Hee-Jong;Park, Sung-Min;Bae, Byung-Jo
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.8 no.1
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    • pp.46-50
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    • 2009
  • Purpose: This study was designed to analyze? the chronic pain of adolescent Taekwondo athletes, to research the understanding about chronic pain of coaches and athletes, to? reduce the development of chronic pain. Materials and Methods: From March. 2006 to June 2007, 210 athletics and 12 coaches of elementary, middle and high school in Kwang-ju city were surveyed. They was evaluated by physical examination, simple radiographs and MRI. Results: In 210 athletics, 162(77.1%) athletes had chronic pain. 19(11.7%) athletes had over three regions of pain, 74(45.7%) athletes had two regions of pain, 69(42.6%) athletes had one region of pain. In 274 cases of 164 athletes, the most common region was foot and ankle(145 cases, 52.9%), followed by hand(47 cases, 17.2%) and knee(38 cases,13.9%), hip(25 cases, 9.1%), and lumbar area(19 cases, 6.9%) The chronic pain was classified by injury type. Contusion of foot was 103 cases(most common), sprain of ankles was 40cases, Contusion of hands and wrists was 28 cases, and so on. The etiologies of injury that causes the chronic pain were match injury in training that is most common, intensive exercise and match injury in competition. Conclusion: The chronic pain was common in adolescent Taekwondo athletes. The ankle and foot were the most common region of chronic pain and the match injury was the most common injury, caused the chronic pain. Although athletes had considerable mental stress about chronic pain, the treatment of chronic pain and rest were insufficient. Therefore the variable effort to prevent injury and to treatment injury must be considered importantly.

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Study of Oil Palm Biomass Resources (Part 5) - Torrefaction of Pellets Made from Oil Palm Biomass - (오일팜 바이오매스의 자원화 연구 V - 오일팜 바이오매스 펠릿의 반탄화 연구 -)

  • Lee, Ji-Young;Kim, Chul-Hwan;Sung, Yong Joo;Nam, Hye-Gyeong;Park, Hyeong-Hun;Kwon, Sol;Park, Dong-Hun;Joo, Su-Yeon;Yim, Hyun-Tek;Lee, Min-Seok;Kim, Se-Bin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.48 no.2
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    • pp.34-45
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    • 2016
  • Global warming and climate change have been caused by combustion of fossil fuels. The greenhouse gases contributed to the rise of temperature between $0.6^{\circ}C$ and $0.9^{\circ}C$ over the past century. Presently, fossil fuels account for about 88% of the commercial energy sources used. In developing countries, fossil fuels are a very attractive energy source because they are available and relatively inexpensive. The environmental problems with fossil fuels have been aggravating stress from already existing factors including acid deposition, urban air pollution, and climate change. In order to control greenhouse gas emissions, particularly CO2, fossil fuels must be replaced by eco-friendly fuels such as biomass. The use of renewable energy sources is becoming increasingly necessary. The biomass resources are the most common form of renewable energy. The conversion of biomass into energy can be achieved in a number of ways. The most common form of converted biomass is pellet fuels as biofuels made from compressed organic matter or biomass. Pellets from lignocellulosic biomass has compared to conventional fuels with a relatively low bulk and energy density and a low degree of homogeneity. Thermal pretreatment technology like torrefaction is applied to improve fuel efficiency of lignocellulosic biomass, i.e., less moisture and oxygen in the product, preferrable grinding properties, storage properties, etc.. During torrefacton, lignocelluosic biomass such as palm kernell shell (PKS) and empty fruit bunch (EFB) was roasted under an oxygen-depleted enviroment at temperature between 200 and $300^{\circ}C$. Low degree of thermal treatment led to the removal of moisture and low molecular volatile matters with low O/C and H/C elemental ratios. The mechanical characteristics of torrefied biomass have also been altered to a brittle and partly hydrophobic materials. Unfortunately, it was much harder to form pellets from torrefied PKS and EFB due to thermal degradation of lignin as a natural binder during torrefaction compared to non-torrefied ones. For easy pelletization of biomass with torrefaction, pellets from PKS and EFB were manufactured before torrefaction, and thereafter they were torrefied at different temperature. Even after torrefaction of pellets from PKS and EFB, their appearance was well preserved with better fuel efficiency than non-torrefied ones. The physical properties of the torrefied pellets largely depended on the torrefaction condition such as reaction time and reaction temperature. Temperature over $250^{\circ}C$ during torrefaction gave a significant impact on the fuel properties of the pellets. In particular, torrefied EFB pellets displayed much faster development of the fuel properties than did torrefied PKS pellets. During torrefaction, extensive carbonization with the increase of fixed carbons, the behavior of thermal degradation of torrefied biomass became significantly different according to the increase of torrefaction temperature. In conclusion, pelletization of PKS and EFB before torrefaction made it much easier to proceed with torrefaction of pellets from PKS and EFB, leading to excellent eco-friendly fuels.