• Journal of Preventive Medicine and Public Health
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• 제2권1호
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• pp.5-22
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• 1969

The urban population of our country is rapidly increasing due to many factors of social structure, and sociologists are predicting that the increase rate of the urban population will be over 50% in 1980's. Above all, the population of the capital city of Seoul, is at present more than four millions. Such centring of people in cities, together with the improvement of the standards of living, caused rapid increase in the amount of fuel consumption, and this consumption of fuels became one of the primary sources of the air pollution in cities. Moreover, the heavy traffic, construction of many tall buildings, and the increasing number of new factories due to the industrial development-all these are contributing to make the matter of air pollution worse and worse in the Metropolitan, whose geographical location is quite unfavorable considered from the view point of air pollution. Most homes in Seoul use briquet as fuel, while oils are used in tall buildings. The CO, $SO_2$, and smoke that come from burning of these fuels are a great threat to the health of the urban population. With the purpose of examining the influence of air pollution upon the public health, written inquiries were made upon respiratory diseases, and the carboxyhemoglobin saturation in the blood was measured to determine whether the air pollution may affect the health of the urban population. Method of Health Examination (1) Investigation of Respiratory Diseases Patients' records were examined to figure out the monthly ambulance rate of respiratory patients to the total number of patients treated. On the other hand, by using the questionnaire form approved by the Medical Research Council's Committee on Research into Chronic Bronchitis, investigators interviewed the examinees and inquired into the respiratory symptoms. (2) Measuring of Carboxyhemoglobin Saturation From the ear lobe of the examinees, with the use of the melangeur for the white blood cell counting, blood was taken, and after diluting it ten times with 0.1% $Na{2}CO_{3}$, again diulting it 20 times with 0.5% $Na_{2}\;CO_{3}$, its absorbancy was measured. The following results are obtained from the investigation. (1) It was found out that 7.7% of the total patients under treatment were suffering from upper respiratory infection, acute or chronic bronchitis, bronchial asthma, pulmonary emphysema and bronchiectasis. Of them all, patients with upper respiratory infection numbered the greatest with 4.8% and patients with acute or chronic bronchitis the next with 2.1%, and their monthly ambulance rate was high from December to February during the winter, and from April to May and from September to October during the changeable seasons. (2) The daily ambulance rate of respiratory patients, it was revealed, had a close connection with the concentration of $SO_2$ and CO in the air. (3) It was found out that men were more subject to respiratory disease than women, and both men and women were more liable to the diseases with the advancing of age. (4) People living at Choong-ku with the heavy traffic and in the industrial zones of Yeungdungpo had high frequency of respiratory symptoms. (5) Considered from the view point of occupations, high frequency was found among those without job, with jobs unknown, merchants and intdustrial workers, whose social status was rather low and traffic policemen who were always exposed to the exhaust gas of cars. As for women, the frequency was detected in the order of those from high to low, housewives who were exposed to briquet gas, women with jobs unknown, women without jobs, whose social status was low. (6) Ex-smokers rather than smokers, of both sexes, had higher frequency. As for men, heavy smokers had high frequency, while in women light smokers had rather high frequency which was presumed to be due to their average old age. (7) Men's average of carboxyhemoglobin saturation was 9.48%, while women's was 11.3%, higher than men's. (p<0.05). Age meant no difference in the case of men, but as for women, the saturation was remarkably high between the ages from 20 to 60. (8) No regional difference was detected in the carboxyhemoglobin saturation. (9) The carboxyhemoglobin saturation was found, in the case of men, in the order of office workers, traffic policemen, students, the unemployed, merchants and industrial workers, drivers; and as for women, the order was housewives, office workers, merchants and industrial workers. (10) No significant correlation was found between the carboxyhemoglobin saturation and the concentration of CO detected in kitchens, or between the carhoxyhemoglobin saturation and the passing of time after exposure to briquet gas. No difference of carboxyhemoglobin saturation was detected between smokers and non-smokers, and the degrees of smoking; only, significant negative correlation was found between the passing of time after smoking and the carboxyhemoglobin saturation. It is ture that air pollution causes or aggravates the respiratory diseases, increases the carboxyhemoglobin saturation in the blood, but what seems to be more hazardous to the health is the air polluted by the briquet gas in the kitchens and on-dol rooms rather than the atmospheric air pollution.

• 한국안전학회지
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• 제33권2호
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• pp.124-131
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• 2018

In consideration of limitations of the classic economic approach to risk evaluation and the psychometric analysis of risk perception, this study applies a facilitated modeling technique to a group of college students in Korea. In this group activities, researchers did not provide a pre-selected list of risk items. Instead, 35 participants had group discussions to generate 63 risk items, to rate their risk level and to evaluate their characteristics in terms of the level of knowledge and dreadfulness. This study also analyzes the influence of mass media, online news papers in particular, on risk perception by counting the number of news articles covering key word corresponding risk items generated. The results show that there are significant differences between the rank order of risk items generated by students and that of statistical or objective risk. Psychometric analyses find that the levels of knowledge and dreadfulness have meaningful correlations with risk level. A well known or a dreadful risk demonstrates a high level of risk. Correlation analyses of media coverage and the risk level also re-confirms strong positive relations. The larger number of news articles a risk issue was covered by, the higher level of risk it showed. It means that college students generated risk items on the basis of what they were exposed by media. The role of mass media in risk perception and the importance of risk communication in risk evaluation are underlined. Implications of research findings and future research are discussed as well.

• Parasites, Hosts and Diseases
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• 제40권1호
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• pp.9-16
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• 2002

The endemic status of clonorchiasis and metagonimiasis along the Geum gang (River) in Okcheon-gun (County) in Korea was examined. From February to December 7000, stools of total 1,081 inhabitants living in 5 villages were examined. Each stool specimen was examined by both the cellophane thick smear method and the formalin-ether sedimentation technique. Egg-positive cases were further analyzed by Stoll's egg-counting technique. and praziquantel was administered to positive cases. The egg-positive rates for Clonorchis sinensis and Metafonimus species were 9.3% and 5.5%, respectively, and the double infection rate was 3.5%. The numbers of eggs per gram (EPG) of feces of C. sinensis and Metafoninus sp. were $918{\pm}1,463$ and $711{\pm}947$, respectively. The egg-positive rates for C. sinensis and Metagoninus sp. in the riverside area were 14.2% and 8.4%, respectively, which were significantly higher than those of the inland area (3.2% and 1.7%. respectively). The egg-positive rates of C. sinensis and Metagoninus sp. in males (16.7% and 10.0%) were significantly higher than those of females (3.5% and 1.8%) However, there were no significant differences of EPG values between localities and sexes. The prevalence of clonorchiasis and metagonimiasis in this survey was significantly lower than that in the previous reports. However. there is still a high prevalence of infection with C. sinensis and Metagoninus sp. in this region. especially in the riverside area.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.275-278
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• 2002

The recognition of the natural background radiation is important not only for radiological education but also for the promotion of people's scientific view about radiation. We made a "room" on the web showing natural background radiation as part of a VRM (Virtual Radiation Museum). The "room" shows the video images of the tracks of charged particles from natural background radiation, alpha and beta ray track from known sources using a Large Scale Diffusion Cloud Chamber. The purpose of this study is to make clear the origin of a kind of track (named A-track) which is thick and easy to recognize with the length less than several cm in the cloud chamber, and to make numerical explanation of its counting rate. The study was carried out using a Large Scale Diffusion Cloud Chamber (Phywe, Germany) installed in the Niigata Science Museum. The Model RNC (Pylon Electronics, Canada) was used as Rn-222 source. Ra-226 activity in RNC was 111.6 Bq calibrated with NIST protocol. Rn-222 gas was injected into the cloud chamber. Continuous video recording with use of Digital Handycam (SONY, Japan) was carried out for 360 min. after injection of Rn-222 gas. The number of alpha-ray track (alpha track) in the video images was analyzed. The growth and decay curve of the total activity of Rn-222 and its alpha emitting progeny were calculated and compared with the count of the alpha tracks. As a result the alpha tracks formed by Rn-222 injection resemble A-Tracks. The relationship between A-track in the cloud chamber and atmospheric Rn is discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.377-379
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• 2007

To reduce the chattering errors of reed switch sensors used for automatic remote measurement of water supply system, a reed switch sensor was analyzed and improved. The operation of reed switch sensors can be described as a mechanical contact by approximation of permanent magnet piece to generate an electrical pulse. The reed switch sensors are used in measurement application by detecting the rotational or translational displacement. To apply for flow measurement devices, the reed switch sensors should keep high reliability. They are applied for the electronic digital type of water flow meters. The reed switch sensor is just installed simply on the mechanical type flow meter. A small magnet is attached on a pointer of the water meter counter rotor. Inside the reed sensor, two steel leaf springs make mechanical contact and apart as rotation of flow meter counter. The counting electrical contact pulses can be converted as the water flow amount. The MCU sends the digital flow rate data to the server using the wireless communication network. But it occurs data difference or errors by chattering noise. The reed switch sensor contains chattering error by it self at the force equivalent position. The vibrations such as passing car near to the switch sensor installed location. In order to reduce chattering error, most system uses just software methods for example using filter and also statistical calibration methods. The chattering errors were reduced by changing leaf spring structure using mechanical hysteresis characteristics.

• Parasites, Hosts and Diseases
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• 제52권1호
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• pp.51-56
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• 2014

The prevalence of helminthic infections was surveyed on a total of 6,178 residents (males 2,549 and females 3,629) in 102 villages of 9 provinces in Lao PDR between 2007 and 2011 under the project of Korea-Laos Collaborative Project for Control of Foodborne Trematode Infections in Lao PDR. Fecal specimens were collected and examined by the Kato-Katz thick smear and Stoll's egg counting techniques. The overall liver/intestinal helminth egg positive rate was 71.9% with a single or mixed infections with Opisthorchis viverrini and minute intestinal flukes (Ov/MIF), Ascaris lumbricoides, hookworms, Trichuris trichiura, Trichostrongylus sp., echinostomes, Taenia spp., and others. Ov/MIF revealed the highest prevalence (55.6%) followed by hookworms (27.8%) and T. trichiura (6.5%). The endemic regions with the highest prevalence of Ov/MIF were Savannakhet, Khammouane, Vientiane (Nam Ngum), Champasak (Khong Island), and Saravane Province. High prevalences of A. lumbricoides (33.8%), hookworms (47.8%), and T. trichiura (32.6%) were observed in Phongsaly, Luang Prabang, and Vientiane (Nam Ngum) areas, respectively. The results of this study highlight helminth parasites of current public health significance in different areas of Lao PDR.

• 대한방사선기술학회지:방사선기술과학
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• 제36권4호
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• pp.291-297
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• 2013

본 연구는 NaI (Tl) 신틸카메라를 이용하여 동적영상 분석에서 계수율 오차가 $T_{1/2}$에 미치는 영향을 알아보고, 이에 대한 점 선원을 이용한 정도관리 방법을 제안하는 것에 목적을 두었다. 18.5 MBq 부터 185 MBq 까지 2 mL 용량의 $^{99m}TcO_4^-$을 주사기에 넣어 점 선원을 제작한 후, Infinia(GE, USA) 감마카메라를 이용하여 10초부터 60초까지 각각 30프레임의 동적영상을 획득하였다. 두 번째 실험으로 5대의 감마카메라(Infinia 2대, Forte 2대, Argus 1대)를 대상으로, 74 MBq의 점 선원으로 90프레임의 동적영상을 획득하였다. 첫 번째 실험의 평균계수율을 10초 단위로 비교한 결과 18.5 MBq부터 92.5 MBq까지의 선원은 10초/프레임에서 60초/프레임까지 평균계수율 간에 유의한 차이를 보이지 않았지만(p>0.05), 111 MBq 이상의 점 선원을 60초/프레임에서 계수율이 유의하게 적게 획득되었다(p<0.01). 이에 따라 5대의 감마카메라에서 90분간 획득한 계수율을 선형 회귀분석한 결과, 4번 감마카메라의 계수 효율은 0.0064%로 가장 낮았고, 경사도와 변동 계수는 각각 0.0042, 0.229로 가장 높게 측정 되었다. 계수율을 카이제곱검정한 결과에서는 비정상적인 요동을 확인하지 못하였고(p>0.02), 분산의 동질성 검정에서 또한 모든 감마카메라의 계수율 간에는 등분산성이 확인되었다(p>0.05). 상관분석에서는 유일하게 계수 효율과 경사도간에 유의한 음의 상관관계가 있는 것으로 분석 되었다(r=-0.90, p<0.05). 마지막으로 -2.5%부터 +2.5%까지 경사도를 변화하여 $T_{1/2}$의 오차를 산출한 결과, $T_{1/2}$이 길수록, 경사도가 높을수록 오차가 커지는 것으로 나타났다. 경사도가 가장 높았던 4번 카메라에서 측정된 수치를 이 결과에 미루어 보았을 때 $T_{1/2}$ 60분까지는 오차가 발생되지 않았다. 결론적으로 의료분야에 사용되는 신틸레이션 감마카메라에 있어 방사선 계수에 대한 엄격한 정도관리가 필요하다고 생각된다. 특히 본 연구에서 계수율이 시간에 따라 변화하는 경향이 파악되었고, 이는 $T_{1/2}$에 영향을 줄 수 있음을 증명하였다. 또한 국내 의료 목적의 신틸레이션 카메라의 계수율에 관한 권고치나 제한치가 없는 점을 미루어 볼 때, 본 연구와 같은 적절한 팬텀 및 관리법의 개발이 필요하다 사료된다.

• Parasites, Hosts and Diseases
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• 제21권2호
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• pp.116-186
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• 1983

An epidemiological study on Clonorchis sinensis infection along the Nam-river (total length ; 186km) flowing in Gyeongsang-nam-do, southern part of Korea, was carried out. Formalin-ether concentration technique and Stoll's egg counting method were employed to figure out the prevalence of C. sinensis infection. For the detection of cercariae from Parafossarulus sp., the snail host of C. sinensis, each snail was placed in aerated tap water, and examined for expelled cercariae. For observing the metacercariae the fresh water fish favorably eaten in raw conditions wore prepared by means of pressing the muscles between two slide glasses and/or by digesting them with artificial gastric juice. The fresh water fish were fed to the rabbits to get the worms and to identify the morphology of adult C. sinensis. The results are summarized as follows: 1. Overall Prevalence of C. sinensis infection was 38.75 from 5,291 examinees; 44.15 (1,408 out of 3,196) in male and 30.4% (637 out of 2,095) in female. 2. The prevalence rates were 42.0% at the upper stream, 41.2% around the vicinity of Jinyanglake, 34.2% at Jinju city, 34.2% at middle stream and 40.3% at down stream regions, respectively. 3. By age, the highest positive rate (53.4∼54.3%) was observed in 30 to 59 years of age. In this age group, the rate in males was 59.7∼62.2%, and in females 42.2∼44.4%, In the age group of less than 19 years it was 7.5∼20.9%. 4. By social strata, the positive rate was 16.5% in the primary school children, 22.6% in school students, 46.2% in teachers and local officers and 49.6% in the general inhabitants. 5. The quantitative examinations with the stool collected from clonorchiasis cases revealed that the light infection (less than 4,000/EPG) was 53.6%, moderate infection (4,001∼10,000 /EPG) 30.3% and heavy infection (more than 10,001/EPG) 16.1%, respectively. More than half of total cases examined were light infection, and 73.2% of female examinees were lightly infected with this cuke. 6. The average value of EPG was 4,963 (male, 6,057; female, 2,557 and the highest value was obtained from the age group of 30 to 59 years (5,240∼6,454). 7. The prevalence of Metagonimus yokogawai infection in humans was 5.5%, and 89.8% of metagonimiasis cases wore double-infected arith C. sinensis. The highest prevalence rate was observed in Jinju city (11.2%). 8. Total of 5,005 Parafossarulus sp., the snail intermediate host of C. sinensis, were examined for the detection of cercariae. The cercarial expulsion rate was 0.34%, and the snails collected in Jin-yang-lake side and in the down stream expelled mainly the cercariae of C, sinensis. 9. About 788 cercariaejday (range: 127∼1,503) were expelled daily from a snail naturally infected with C. sinensis. The snails which released more than 1,000 cercariae/day were 30.8% out of total collected. A snail uniquely released 5,840 cercariae/day in this study. 10. The other trematode cercariae besides C. sinensis were also detected, and the rates out of total snails were the cercariae of Losogenes liberum 6.71%, Cyathocotyle orientalis 0.26%, Notocotylus attenuatus 2.52% and Mucobucaris 0.54%, 11. Ten out of 18 species of fresh water fish caught along the river harbored the metacercariae of C, sinensis. The highest rate of metacercarial infection in fish was detected in Pseudorasbora larva (85.9%). The fish mainly eaten by the inhabitants along the Nam-river, and the metacercarial infection rates were: Zacco platypus 8.0%, Hemibarbus sp. 18.2∼26.7%, Gnathepcgcn sp. 37.5%, Ischikauia steenackeri 42.9% and Pseudogobio esocinus 16.7%. 12. Out of 36 P. larva, the number of metacercariae were about 109 (ranEe; 18∼446) per fish and 27 per gram of flesh. The fish caught in spring harbored the highest number of metacercariae. As indicated above, the prevalence of C. sinensis infection in the inhabitants residing around the Nam-river was relatively high. The farther toward the upper stream areas, the higher was the positive rate of C. sinensis infection, and most of clonorchiasis cases were lightly infected. The snail hosts of C. sinensis distributed all around the Nam-river. Several species of freshwater fish were infected with the metacercariae of C. sinensis and the infection rates were relatively high. To prevent C. sinensis infection in the endemic areas, the effective health education system is suggested as a control measure, although mass treatment is also expected to be useful, using chemotherapeutic agents such as "praziquantel", a recently developed anthelminthic for C. sinensis inftraction.

• Journal of Periodontal and Implant Science
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• 제31권3호
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• pp.513-529
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• 2001

For reconstruction of the bony defect, various artificial substitutes were developed. Among them, there has been a study of calcium phosphate coated bone substitutes for increasing attachment of osteoblasts in vivo. The purpose of this study was to evaluate the effects of serum and platelet-rich plasma (PRP) on calcium phosphate coated culture plate for the initial attachment, proliferation and activity of osteoblasts. After sampling the blood from white rats and concentrating by centrifugation, the amount of attachment of PDGF-BB and $TGF-{\beta}$ on the calcium phosphate coated culture plate was measured. Cultured HOS and ROS 17/2.8 cell was measured on attachment level and proliferation rate of osteoblasts. Alkaline phosphatase activity of HOS and ROS 17/2.8 cell was measured for studying on the activating rate of osteoblast. 1. Counting the amount of platelets of seperated plasma and PRP, the average number of platelets was 177,003 $cell/{\mu}l$ in plasma, and 1,656,062 $cell/{\mu}l$ in PRP, which was about 9 times as high as in plasma. 2. Amount of PDGF-BB deposited at calcium phosphate coated plate had increased by the total amount of plasma and PRP on the culture plate, whereas $TGF-{\beta}$had been deposited on the plate only when treated by $50{\mu}{\ell}$ of PRP(p<0.01). 3. After plating serum and PRP for 3 hours, we attached with HOS and ROS17/2.8 cell for 1 hour and 4 hours. There were no significant difference of the attachment between serum and control group, whereas there were significantly difference of the attachment between depositioning of PRP and control group. 4. After attaching plasma and PRP for 3 hours, cell number has much increased when HOS and ROS17/2.8 cell had been cultured for 48 hours(p<0.05). 5. After attaching plasma and PRP for 3 hours, concentration of alkaline-phosphatase has increased when HOS and ROS17/2.8 cell had been cultured for 48 hours(p<0.01). These results suggested that PRP affected on initial cell attachment rather than proliferation and activation of osteoblasts at calcium phosphate coated plate.

• Archives of Plastic Surgery
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• 제37권6호
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• pp.721-725
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• 2010

Purpose: The survival of composite graft is dependent on three steps, (1) plasmatic imbibitions, (2) inosculation, and (3) neovascularization. Among the many trials to increase the survival rate of composite graft, prostaglandin E1 (PGE1) has beneficial effects on the microcirculatory level with vasodilating, antithrombotic, anti-inflammatory and neoangiogenic properties. Lipo-PGE1 which is lipid microspheres containing PGE1 had developed to compensate the systemic and local side effects of PGE1. This study was proposed to determine whether Lipo-PGE1 administration enhanced the survival of composite graft through neovascularization quantitatively in a rabbit ear model. Methods: Fourteen New Zealand White Rabbits each weighing 3~4 kg were divided in two groups: (1) intravenous Lipo-PGE1 injection group and (2) control group. A $2{\times}1\;cm$ sized, full-thickness rectangular composite graft was harvested in each auricle. Then, the graft was reaaproximated in situ using a 5-0 nylon suture. For the experimental group, $3{\mu}g$/kg/day of Lipo-PGE1 ($5{\mu}g$/mL) was administered intravenously through the marginal vein of the ear for 14 days. The control group was received no pharmacologic treatment. On the 14th postoperative day, composite graft of the ear was harvested and immunochemistry staining used Monoclonal mouse anti-CD 31 antibody was performed. Neoangiogenesis was quantified by counting the vessels that showed luminal structures surrounded by the brown color-stained epithelium and counted from 10 random high-power fields (400x) by independent blinded observer. Statistical analysis (Wilcoxon Signed Ranks test for nonparametric data) was performed using SPSS v12.0, with values of p<0.05 considered significant. Results: The mean number of the microvessels was $15.48{\pm}8.65$ in the experimental group and $9.82{\pm}7.25$ in the control group (p=0.028). Conclusion: The use of Lipo-PGE1 facilitated the neoangiogenesis, resulted in the improvement of the survival rate of graft. On the basis of this results, we could support wider application of Lipo-PGE1 for more effective therapeutic angiogenesis and successful survival in various cases of composite graft in the human.