• 한국환경생태학회지
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• 제23권3호
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• pp.258-271
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• 2009

외부환경 변화와 천이의 영향으로 쇠퇴현상이 나타나고 있는 서울시 소나무림의 식생환경을 개선하고자 교목층 우점종의 경쟁관계, 하층식생내 경쟁종 출현 유무, 관리정도 등에 근거하여 유형을 구분하고 생태적 관리방안을 제안하였다. 서울시 소나무림을 생태적 특성에 따라 분류하면 소나무순림에 속하는 토지극상림(26.1%)과 소나무순림(21.5%), 소나무와 타 수종이 경쟁하는 소나무-신갈나무림(28.0%), 소나무-리기다소나무림(13.1%), 소나무-상수리나무림(4.2%)등으로 구분되었다. 이들 유형에 대한 정밀한 식생조사 결과, 토지극상, 답압피해, 식생관리로 인해 교목층과 하층에 경쟁종이 출현하지 않아 소나무림 유지가 가능한 4개 군집은 하층식생 보완 등 소극적인 관리가 필요하였다. 반면 교목층과 하층에 소나무와 경쟁수종인 낙엽성 참나무류와 외래종이 출현하는 4개 군집은 생태적 지위가 동일한 경쟁종관리, 하층식생 도입 등 적극적인 관리기법을 적용해야 소나무군집을 유지할 수 있을 것이다.

• Elastomers and Composites
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• 제34권2호
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• pp.156-176
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• 1999

Rubber chemicals such as accelerators, antidegradants, vulcanizing agents, processing agents and retarders are very important to the production and protection of tires and rubber goods. The use of accelerators and antidegradants are evaluated in various tire components. This paper will focus on how to vulcanize tires economically and maintain the physical properties of each tire component without severe degradation due to oxygen, heat and ozone. Also, new non-nitrosoamine accelerators and non-staining antiozonants will be discussed. Lastly, the future requirements of antidegradants and accelerators in the tire industry will be reviewed. Tires have been vulcanized with Sulfenamides as primary accelerators and either Guamdine's or Thiurams as secondary accelerators to achieve proper properties at service conditions. However, interior components such as the carcass can be vulcanized with Thiazoles as a primary accelerator to cure faster than the external components. Using the combination of Sulfenamide with secondary accelerators in a tire tread compound and the combination of a Thiazole and Guanidine in a carcass compound will be presented with performance data. Uniroyal Chemical and another Rubber Chemical Manufacturer have developed, "Tetrabenzyl Thiuram Disulfide," (TBzTD) as a non-Nitrosoamine accelerator, which could replace Nitrosoamine generating Thiurams. This new accelerator has been evaluated in a tread compound as a secondary accelerator. Also, Flexsys has developed N-t-butyl-2-benzothiazole Sulfenamide (TBSI) as a non-Nitrosoamine accelerator which could replace 2-(Morpholinothio) -benzothiazole (MBS), a scorch delayed Sulfendamide accelerator. TBSI has been evaluated in a Natural Rubber (NR) belt skim compound vs. MBS. An optimum low rolling resistant cure system has been developed in a NR tread with Dithiomorpholine (DTDM). Also, future requirements for developing accelerators will be discussed such as the replacement of DTDM and other stable crosslink systems. Antidegradants are divided into two different types for use in tire compounds. Internal tire compounds such as apex, carcass, liner, wire breaker, cushion, base tread and bead compounds are protected by antioxidants against degradation from oxygen and heat due to mechanical shear. The external components such as sidewall, chafer and cap tread com-pounds are protected from ozone by antiozonants and waxes. Various kinds of staining and non-staining antioxidants have been evaluated in a tire carcass compound. Also, various para-phenylene diamine antiozonants have been evaluated in a tire sidewall compound to achieve the improved lifetime of the tire. New non-staining antiozonants such as 2, 4, 6-tris-(N-1, 4-dimethylpentyl-p-phenylene diamine) 1, 3, 5 Trizine (D-37) and un-saturated Acetal (AFS) will be discussed in the tire sidewall to achieve better appearance. The future requirements of antidegradants will be presented to improve tire performance such as durability, better appearance and longer lasting tires.

• Advances in pediatric surgery
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• 제2권1호
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• pp.33-41
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• 1996

This report present the result of the national survey of pediatric surgeons' preferences on diagnosis and treatment of Hirschsprung's disease(HD) carried out in 1993. The questionnaires were sent to twenty-seven members of the Korean Association of Pediatric Surgeons (KAPS) working in twenty-four institutions. The questionnaires were designed to determine the individual surgeon's preference for the methods of diagnosis and treatment of the disease. Twenty-three pediatric surgeons from twenty institutions returned completed forms. The total number of patients diagnosed with HD in 1992 was 190 in this group. The estimated incidence of HD was 1/3,900. The most important symptom was delayed meconium passing and the most preferred diagnostic procedure was barium study. Anorectal manometric examination was carried out by 13 pediatric surgeons and 19 confirmed the diagnosis before operation by rectal biopsy, 12 with full-thickness biopsy and 7 with suction. Frozen section biopsy during operation was done by 22 surgeons. Eight surgeons did one stage operation if the age of the patient is suitable. Definitive operation was usually done at the age of 6 to 11 months. The most preferred operation was Duhamel procedure done by 19. Enterocolitis was the most serious complication of HD. Most of patients had normal continence within 6 to 12 months after operation. The follow-up period was less than 6 years in 16 surgeons. The results were presented at the 9th annual meeting of KAPS in June of 1993. This is the first national survey of HD and it can provide guidelines of diagnosis and treatment of Hirschprung's disease even though it is not a detailed study of patient data.

• 한국자원식물학회지
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• 제21권5호
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• pp.374-387
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• 2008

본 연구는 우리나라 남해안과 제주도 일대 해안사구에 분포하는 유관속식물을 대상으로 2006년 2월부터 11월까지 조사한 결과, 조사지역내에 분포하는 식물은 51과 130속 152종 1품종 18변종 등 총 171분류군으로 관찰되었으며, 주요 출현종은 Calystegia soldanella(갯메꽃), Ischaemum anthephoroides(갯쇠보리), Imperata cylindrica va. koenigii(띠), Vitex rotundifolia(순비가나무), Carex pumila(좀보리사초), Carex kobomugi(통보리사초) 등으로 나타났다. 본 지역에서 조사된 171종류의 식물자원의 유용도를 분석한 결과 총 113종류의 자원식물이 분류되었으며, 식용자원(Edible source, E)은 73종류(40.5%), 약용자원(Medicinal source, M)은 61종류(33.9%), 초지자원(Pasture source, P)은 22종류(12.2%), 관상자원(Ornamental source, O)은 16종류(8.9%), 섬유자원 (Fiber source, F)은 7종류(3.9%), 목재자원(Timber source, T)은 1종류(0.5%)의 순으로 나타났다. 한국특산식물은 1분류군이 조사지역내 분포하며, 식물구계학적 특정식물 중 I III IV V등급 식물은 24과 28속 29분류군으로 소산식물 171분류군의 16.9%로 나타났으며, 귀화식물은 9과 16속 19분류군로 우리나라 전체 귀화식물 271종류의 7.0%이다.

• 한국환경복원기술학회지
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• 제7권2호
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• pp.75-86
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• 2004

This study aims to figure out ecological characteristic of natural forests focusing on vegetation as a way of ecological renovation for the restoration of naturalness for golf courses that were constructed in the Country and to present vegetation models and appropriate tree species for the purpose. The study site is P golf club, which is located in Gapyong-gun, Kyeonggi Province. The site is within a forest where the grade from the natural ecology map is the first one and the level from the green index accounts for the eight, thus showing a typical environment for a golf course in terms of location. The location of the site explains a reason for restoration. The major substance of the study is to conduct ecological evaluation of vegetation structures around and inside the golf course and to present a vegetation model. In order to evaluate the ecological characteristics of the vegetation structures, the analysis of the study covered succession stages, multi-layer vegetation structures and species diversity. Plant communities that have high species diversity were selected for the vegetation model and proper density and species were proposed considering the number of species and individuals and distances between trees. The vegetation restoration model targets succession into an oak forest. Within a unit of 100 $m^2$, the recommended model include a tall-tree layer with 11 trees such as Quercus serrata and Quercus mongolica, a sub-tall-tree layer with 12 trees including Quercus mongolica, Quercus serrata, Prunus sargentii, Fraxinus rhynchophylla and Acer pseudo sieboldianum, a shrub layer with 32 trees from 16 species, and a grass layer with a cover rate of 45 %. The proposed vegetation restoration model needs to apply to : 1) damaged natural forests by the construction of golf courses; 2) boundaries between golf courses and surrounding forests; 3) buffer zones; 4) open spaces in between courses; and 5) areas between greens and tees where open spaces are available in a mass. In conclusion, one of the most important factors in presenting a vegetation model for the restoration of naturalness in the golf course and other damaged forests is to provide multi-layer vegetation structures that are composed of native species. As for the specific application for the site, it is recommended to manage the vegetation in such a way that the environment of the site can have a similar environment to the surrounding forest which is expected to succeed into an oaks-dominant one.

• 한국수정란이식학회지
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• 제31권1호
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• pp.1-7
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• 2016

Xenotransplantation involves multiple steps of immune rejection. The present study was designed to produce nuclear transfer embryos, prior to the production of transgenic pigs, using fibroblasts carrying transgenes human complement regulatory protein hCD59 and interleukin-18 binding protein (hIL-18BP) to reduce hyperacute rejection (HAR) and cellular rejection in pig-to-human xenotransplantation. In addition to the hCD59-mediated reduction of HAR, hIL-18BP may prevent cellular rejection by inhibiting the activation of natural killer cells, activated T-cell proliferation, and induction of $IFN-{\gamma}$. Transgene construct including hCD59 and ILI-18BP was introduced into miniature pig fetal fibroblasts. After antibiotic selection of double transgenic fibroblasts, integration of the transgene was screened by PCR, and the transgene expression was confirmed by RT-PCR. Treatment of human serum did not affect the survival of double-transgenic fibroblasts, whereas the treatment significantly reduced the survival of non-transgenic fibroblasts (p<0.01), suggesting alleviation of HAR. Among 337 reconstituted oocytes produced by nuclear transfer using the double transgenic fibroblasts, 28 (15.3%) developed to the blastocyst stage. Analysis of individual embryos indicated that 53.6% (15/28) of embryos contained the transgene. The result of the present study demonstrates the resistance of hCD59 and IL-18BP double-transgenic fibroblasts against HAR, and the usefulness of the transgenic approach may be predicted by RT-PCR and cytolytic assessment prior to actual production of transgenic pigs. Further study on the transfer of these embryos to surrogates may produce transgenic clone miniature pigs expressing hCD59 and hIL-18BP for xenotransplantation.

• 대한지역사회영양학회지
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• 제19권5호
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• pp.490-498
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• 2014

Objectives: This study was conducted to propose the need of re-establishing the criteria of the body weight classification in the elderly. We compared the Asia-Pacific Region Criteria (APR-C) with Entropy Model Criteria (ENT-C) using Morbidity rate of chronic diseases which correlates significantly with Body Mass Index (BMI). Methods: Subjects were 886 elderly female participating in the 2007-2009 Korea National Health and Nutrition Examination Survey (KNHANES). We compared APR-C with those of ENT-C using Receiver Operating Characteristics (ROC) curve and logistic regression analysis. Results: In the case of the morbidity of hypertension, the results were as follows: Where it was in the T-off point of APR-C, sensitivity was 67.5%, specificity was 43.1%, and Youden's index was 10.6. While in the cut-off point of ENT-C, it was 56.7%, 56.6%, and 13.3 respectively. In the case of the morbidity of diabetes, the results were as follows: In the cut-off point of APR-C, Youden's index was 14.2. While in the cut-off point of ENT-C, it was 17.2 respectively. The Area Under the ROC Curve (AUC) of the subjects who had more than 2 diseases among hypertension, diabetes, and dyslipidemia was 0.615 (95% CI: 0.578-0.652). Compared to the normal group, the odds ratio of the hypertension group which will belong to the overweight or obesity was 1.79 (95% CI: 1.30-2.47) in the APR-C, and 2.04 (95% CI: 1.49-2.80) in the ENT-C (p < 0.001). Conclusions: We conclude that the optimal cut-off point of BMI to distinguish between normal weight and overweight was $24kg/m^2$ (ENT-C) rather than $23kg/m^2$ (APR-C).

• 한국작물학회지
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• 제46권6호
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• pp.473-477
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• 2001

벼-자운영의 연속재배체계 확립을 통해 자운영을 지속적으로 이용하고자 기계이앙 및 직파 파종시기와 재배양식을 달리하여 시험한 결과는 다음과 같다. 1. 자운영의 식물체 무기성분함량은 T-N이 2.92%, P$_2$ $O_{5}$가 0.74%, $K_2$O가 4.28%로 ㏊당 30 ton정도의 녹비가 생산되면 벼 재배시 인산을 제외하고는 표준시비량 이상에 해당되었다. 2. 자운영 녹비의 포장 잔존율은 초기 1주일 이내에 급격히 떨어져 토양에 환원되었고, 무기성분의 잔존율도 같은 경향이었다. 질소성분에 비해 인산과 가리성분의 환원정도가 더 빨랐고, 심토에 비해 표토에서 낮은 결과를 보였다. 3. 무경운 직파재배에서는 5월 25일 이후 파종할 경우 파종 시기에 관계없이 벼 수확후 자연적인 자운영 재입모로 다음해 피복이 가능하였다. 4. 무경운이앙은 자운영의 지상부 예취 없이는 벼 이앙이 불가능하여 농가활용이 곤란하였고, 경운이앙은 5월 25일 이앙시 벼 수확후 자운영의 자연적인 입모가 극히 불량한 반면, 6월 4일 경운후 이앙시 벼의 충분한 생육과 수량이 확보되고 운영의 자연적인 재입모로 다음해에도 자운영 조성이 가능하였다. 5. 자운영포장에 벼 이앙시 결주율은 경운에 비해 무경운에서 높았고 이앙심도도 무경운이앙시 예취된 자운성 때문에 얕아 도복이 우려되었다. 6. 자운영 후작 포장의 벼 수량은 무경운직파의 경우 입모가 불량하여 수량이 낮았으나, 경운이앙의 경우 자운생이 재배되지 않은 대조구에 비해 4~6% 증수되었다.

• 한국치위생학회지
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• 제5권2호
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• pp.171-184
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• 2005

In order to investigate correlation between mother's dental ca re for her children and their dental caries, this study was conducted wi th the dental examination record of 365 children who showed the same number of questionnaires with those examined for dental conditions and questionnaires written by mothers among children between three and six years of age and their mothers in Yeoncheon, Gyeonggi province in June 2004 to estimate frequency and percentage of general properties of subjects and mother's oral health care behaviors for her children by research items, to carry out cross-tabulation analysis and correlation analysis following Chi-square distribution for the presence of dental caries in deciduous teeth and oral health care behaviors, and to use decision tree analysis among data mining techniques for those factors associated with the presence of dental caries in deciduous teeth, and drew the following conclusions. 1. For mother's oral health care behaviors and attitudes for her children, 225 mothers(61.6%) confirmed their children's teeth-brushing; 278(76.2%) used no fluorine; and 286(78.6%) observed their children's teeth, 322 mothers(88.2%) instructed their children in teeth-brushing while 268 (73.4%) provided dental care, 232 mothers(63.7%) treated their children's cavity; 290(79.4%) believed that their children had good dental conditions; and 294(80.5%) answered that they began to provide their children with dental care in deciduous teeth. 2. As for the presence of dental caries in deciduous teeth and dental health care behaviors, there were statistically significant differences in employment, confirmation after teeth-brushing, teeth observation, instruction in time for teeth-brushing, use of fluorine, cavity treatment, time for dental care, and perception of dental conditions(p<0.05). 3. As for correlation between dental caries in deciduous teeth and oral health care behaviors, mothers who worked, who believed that their children didn't have good dental condition, and who thought that it was necessary to begin to provide dental care in permanent teeth were found to get their children to suffer from dental caries in deciduous teeth. Besides, those who failed to confirm teeth-brushing, who used no fluorine, and who failed to observe teeth and gave no instruction in time for teeth-brushing were shown to get their children to suffer from dental caries in deciduous teeth. 4. Variables to determine the presence of dental caries in deciduous teeth were classified by cavity treatment, mother's employment, time for dental care, and observation of children's teeth. The first node to determine the presence of dental caries in deciduous teeth was found to be cavity treatment; the next criteria for classification after cavity treatment were shown to be mother's employment and time for dental care. In case of children with no cavity, they were found to be mother's employment and teeth observation.

• 한국치위생학회지
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• 제11권4호
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• pp.581-593
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• 2011

Objectives : The purpose of this study was to examine the relationship of the work environments of dental hygienists to their occupational diseases in a bid to provide some information on their health care, health promotion and the prevention of occupational diseases. Methods : The subjects in this study were 300 dental hygienists who worked in Seoul, urban communities involving large cities and rural areas. One-on-one interviews and a self-administered survey were implemented with their consent. Results : The findings of the study were as follows: 1. 60 percent of the dental hygienists investigated replied that they had occupation-related physical symptoms. By the length of service, the dental hygienists who worked for six to 10 years had the most symptoms. 2. Out of the occupation-related symptoms, the most prevalent symptom was a pain in the shoulders and neck(41%), followed by a pain in the lower back, a pain in the legs, a pain in the wrists and skin diseases. The most painful parts of the body were hands and arms. 3. In regard to the relationship between the general characteristics and the intensity of pain, the highest group of the dental hygienists in Seoul replied that they had a severe pain, and the lowest number of those in the large cities gave the same answer. 4. Concerning the cause of occupational diseases, 65.7 percent cited the wrong posture. 5. As to relationship between the general characteristics and regular hospital-visit experiences for the prevention of pain during work hours, many of the dental hygienists who were in their 40s and 50s visited hospitals from time to time, and many of those in their 20s never did that. 6. In regard to links between the general characteristics and an opinion on the necessity of regular education, many of the respondents from Seoul and urban regions involving large cities considered it necessary to receive education on a regular basis. By daily work hours, the highest number of those who worked for eight hours or less considered that necessary, and lots of those who worked for 11 hours didn't consent to that. The gaps between them were statistically significant(p<0.05). Conclusions : Given the findings of the study, daily work hours and length of service were two integral factors to affect the regular hospital-visit experiences and pain, and the wrong posture was identified as the most common cause of occupational diseases. To ensure the successful prevention of occupational diseases, dental hygiene students should be taught the importance of occupational disease before they start to work, and supplementary education should be provided for dental hygienists to work in the right posture.