• Clinical and Experimental Reproductive Medicine
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• v.23 no.1
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• pp.11-24
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• 1996

The number of multifetal pregnancies has increased dramatically as a result of the widespread clinical use of ovulation induction and assisted reproductive technology(ART) in infertile patients. In multifetal pregnancies, the adverse outcome is directly proportional to the number of fetuses within the uterus, primarily because of an increased predisposition to premature delivery. It is extremely difficult to counsel patients about the expected outcome of pregnancies involving three or more fetuses. To increase the chances of delivering infants mature enough to survive without being irreversibly damaged by the sequelae of marked prematurity, selective fetal reduction(SFR) to the smaller number of fetuses should be considered in multifetal pregnancies. From January, 1991 to December, 1992, transabdominal SFR in multifetal pregnancies was performed in 22 patients including 13 triplet, 7 quadruplet, 1 quintuplet and 1 heptuplet pregnancies. Transabdominal SFR using intracardiac KCI injection and aspiration of amniotic fluid was carried out in 8-13 weeks of gestation. After procedure, 20 patients were remained as twin pregnancies, and 2 patients as triplet pregnancies. There have been 11 sets of twin delivery including 2 stillbirths, 2 sets of triplet delivery including 1 stillbirth, and 1 singleton delivery. Six cases were delivered after 37 weeks of gestation, 4 cases in 33 - 37 weeks, and 1 case in 30 weeks. Unfortunately, 3 stillbirths occurred in 20-24 weeks of gestation, and 4 cases were aborted. As 7 losses of pregnanancy including 1 case of septic abortion occurred, the delayed fetal loss rate was 38.9%(7/18) in transabdominal SFR. All babies born after 30 weeks of gestation were healthy, and no fetal anomaly directly related to the procedure was encountered. From July, 1993 to February, 1995, transvaginal SFR was performed in 20 patients including 15 triplet, 4 quadruplet and 1 quintuplet pregnancies. Transvaginal SFR using the same method as transabdominal SFR was carried out in 8-11 weeks of gestation. After procedure, 19 patients were remained as twin pregnancies, and 1 patient as singleton pregnancy. There have been 13 sets of twin delivery including 2 stillbirths, and 1 singleton delivery. Six cases were delivered after 37 weeks of gestation, 5 cases in 36-37 weeks, and 1 case in 30 weeks. Unfortunately, 2 still-births occurred in 20 weeks and 21 weeks of gestation, respectively, and 2 cases were aborted. As 4 losses of pregnancy including 1 case of septic abortion occurred, the delayed fetal loss rate was 25.0%(4/16) in transvaginal SFR. No fetal anomaly directly related to the procedure was encountered. It is suggested that transvaginal SFR could be performed more easily and earlier with the lower fetal loss rate as compared with transabdominal SFR. In conclusion, SFR is a rather safe and ethically justified procedure that may improve the outcome of multifetal pregnancies.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.337-347
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• 1987

Spary and vapor drift injuries of apple, pear, and peach seedling caused by soil-applied oxyfluorfen were studied in a greenhouse. Bud bursting rate of all fruit trees was reduced by both spray and vapor drifts of oxyfluorfen, but reduction in bud bursting rate of pear and peach was greater than that of apple trees. Reduction in the number of leaves per shoot of apple and peach was greater than that of pear trees. Leaf injury of pear was most severe and occurred earliest, but leaves of peach were least injured, Leaf injuries of pear and apple were caused by both spray and vapor drifts, but leaves of peach was injured largely by vapor drift. Reduction in shoot growth of and pear was greater than that of peach trees. Shoot growth of pear was more rapidly retared compared with apple trees. In the field, oxyfluorfen delayed the time of bud bursting in young apple trees. Oxyfluorfen applied between initiation and completion of bud bursting delayed bud bursting more than earlier application although ultimate number of bursted buds was similar to control. The number of leaves per shoot and total length of shoots were lower than control until 40 days after application of oxyfluorfen, and then were similar to control because of vigorous growth after May.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.1
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• pp.26-39
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• 2013

Yield reduction in major cereal grains seems unavoidable with the existing cropping systems under the projected climate change in Korea. Crop models were used to predict the effects of planting date shift on grain yields of rice, winter barley and soybeans at 64 agroclimatic zones in Korea. The shift of planting date by 7, 14, and 21 days before and after the recommended planting dates were incorporated in DSSAT experiment files to simulate growth, development and grain yields of major cereal crops. These included 3 rice cultivars representing early-, medium- and late-maturity groups, 1 winter barley and 1 soybean cultivars. Partial mitigation in yield reduction was found with earlier planting in the early maturing rice cultivar and with delayed planting in the late maturing rice cultivar under the RCP8.5 projected climate change in Korea. Additional yield increase in winter barley was expected by earlier planting treatments. Soybean showed a positive effect on grain yield with earlier planting. However, the rate was much lower than the case with winter barley and delayed planting caused yield reduction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.325-330
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• 2004

This study was carried out to determine adequate planting date, to compare the growth characteristics between early and late maturing cultivars, and to provide the data for the cultivation techniques of soybean [Glycine max (L.) Merr.] in double cropping system with winter crops on paddy field in Korea. Cultivars were planted on 26 May, 16 June, and 7 July with a planting density of $70cm(row\;widtb)\;{\times}\;10cm$ (planting spacing). Seed yield of soybean planted on June 16 and July 7 was approximately $37\%\;and\;53\%$, respectively, less than that of conventional planting date of May 26 in Pungsan-namulkong, and planted on June 16 and July 7 was about $30\%\;and\;37\%$, respectively, less then that of conventional planting date of May 26 in Hanamkong. The number of pods and seeds per plant decreased as planting date delayed. Seed weight increased in Pungsan-namulkong but decreased in Hannamkong as planting date delayed. The flowering date was late in delayed planting plots, but it was shorted for days from emergence to flowering and from emergence to maturity. The plant height of Hannamkong was greater than Pungsan-namulkong from the emergence to flowering stages, but in contrast, it was greater in Pungsan-namulkong than Hannamkong after flowering stage (50d after emergence) when it planted on May 26. There were no significant differences between two soybean cultivars at planting dates of June 16 and July 7. Leaf number, leaf area, and dry matter were also reduced by late planting, and Both of them were shown in high reduction at the later planting. There was a high significant difference at the flowering $(r\;=\;0.87^{**})$ and pod formation $(r\;=\;0.91^{**})$ stages between leaf dry matter and seed yield. Crop growth rate (CGR) was greater at $R2\~R3$ growth stages compared to $R3\~R4\;or\;R4\~R5$ growth stages in two soybean cultivars and the greatest CGR was obtained at planting date of May 26 in two soybean cultivars except for R4-R5 growth stage in Pungsan-namulkong. There was a highly significant positive difference between the seed yield and the leaf area index (LAI) across R3 to R4 and R2 to R3 stages. The photosynthetic rate $(P_N)$ of the uppermost leaf position had no significant difference among planting dates and between two soybean cultivars. However, $P_N$ of the $7^{th}$ leaf position increased as the planting date delayed.

• Journal of Environmental Health Sciences
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• v.47 no.3
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• pp.245-258
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• 2021

Objectives: In many previous studies, endocrine disruptors (EDCs) have been found to affect delays in puberty. Various EDCs have been reported on, but there have been only limited epidemiologic studies on the effects of exposure to environmental heavy metals and pyrethroid pesticides on puberty delay. Therefore, the aim of this study was to investigate the association of exposure to environmental mercury, cadmium, and pyrethroid pesticides with delayed puberty in children based on national survey data that represents Korean children. Methods: We selected 450 children at the ages of 9-11 years old from the third Korean National Environmental Health Survey (3rd KoNEHS). The relations of urinary Hg, Cd, and 3-PBA with pubertal development were evaluated using multiple logistic regression analyses. Results: Urinary Hg levels were significantly associated with delayed puberty in boys [testicle development: OR=0.41 (95% CI: 0.20, 0.84); genitalia development: OR=0.35 (95% CI: 0.15, 0.81)]. Girls with higher Hg levels were more likely to experience delayed menarche [OR=0.23 (95% CI: 0.06, 0.90)]. We observed a significant 49% reduction in odds for menarche per increasing unit of urinary cadmium levels [OR=0.51 (95% CI: 0.24, 1.01)]. In addition, urinary 3-PBA showed a negative association with genitalia development in boys and menarche in girls [genitalia development: OR=0.73 (95% CI: 0.55, 0.96); menarche: OR=0.56 (95% CI: 0.32, 1.00)]. Conclusions: The results of this study support the hypothesis that exposure to environmental mercury, cadmium and pyrethroid pesticides may affect puberty delays. Additional evidence needs to be obtained through further prospective studies.

• Journal of Korean Foot and Ankle Society
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• v.1 no.1
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• pp.51-58
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• 1997

The purpose of this study is to evalute the efficacy af the Ilizarov external fixation for the surgical treatment. of the tibial plafond fractures. We reviewed retrospectively fourteen cases of tibial plafond fractures with moderate to severe soft. tissue damage, which were fixed with Ilizarov external fixator. Using the AO Muler classification, there were four Type C1 fractures, six Type C2 and four Type C3. In most, of the cases, the ankles were operated on with other associated fractures within a few days after injury. We reduced the fracture indirectly by soft issue taxis and fixed externally across the ankle joint. using the circular external fixator with tensioned wires and ankle hinge. In cases of inadequate closed reduction, we applied limited open reduction and internal fixation. Range of motion exercise began immediately. Postoperative follow-up averaged fourteen months (ranges, 8-30 months). Overall clinical results rated good or excellent in 7 cases, fair in 4 and poor in 3. There were three cases of pin tract infection which were resolved with short-term antibiotics and local care; one delayed wound closure in a patient. whose fracture was associated with Type III open wound; one wound slough in a patient associated with Type II open wound, which was closed later by skin graft; and one osteoarthritis. From this review, we concluded that cross-ankle circular external fixation with tensioned wires with or without. limited open reduction is a reasonable alternative for the treatment of the tibial plafond fractures with severe soft tissue damage.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.4
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• pp.419-427
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• 1994

Because of the prominence of the nose and its central location, it is the most frequently encountered fractures in the face. Yet reports about the nasal bone fractures are virtually rare in the oral and maxillofacial surgical literatures. This is a retrospective study on 19 nasal bone fractures treated in Chosun university hospital Department of Oral & Maxillofacial Surgery from Jan. 1991 to Sep. 1993, under admission to our Dept. and the obtained results were as follows. 1. Of the 240 patients with facial bone fractures, 28 patients suffered nasal fractures(12%) and male to female ratio was 5.3:1. 2. The most frequent cause was traffic accidents(39%)m, the next fall down(36%), first blow(4%). 3. The age frequency was the highest in the fifth decade (32%). 4. Clinical classification of nasal fractures was simple fractures(74%), combined fractures(26%), and single fractures(37%), combined fractures(63%). 5. The most frequently combined site was maxilla(50%). 6. Treatments of nasal fractures were closed reduction(63%), open reduction(5%), and secondary rhinoplasty(32%). 7. The initial treatment time from accident was 1.7 days in single fractures, and 3.5 days in combined fractures, and the period of splint retained was about 8.2 days in single fracture, about 8.7 in combined fracture. 8. It was necessary to treat secondarily in delayed treatment, and all treatment methods showed relatively good prognosis. 9. Closed reduction was treated under local anesthesia, but open reduction & secondary rhinoplasty was treated under general anesthesia except 1 case. 10. The complications were disturbance of swellings 5 cases, ethetic problem 5 cases, epiphora 3 cases, abnormal sensation 6 cases in relation with other fractures.

• Clinics in Shoulder and Elbow
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• v.1 no.2
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• pp.230-235
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• 1998

Fractures of the scapula are relatively uncommon injuries and treatment in the vast majority of cases remains nonsurgical and the results have been quite satisfactory. But the scapular fracture itself may be neglected because of its high incidence of many kinds of associated injuries so its delayed treatment sometimes gives bad and unpredictable results. Although open reduction and internal fixation has been accepted as the treatment of choice for displaced intra-articular fractures in many anatomical regions, there has been no definite treatment principles of surgical indications and approaches in the glenohumeral joint. At our institution, II displaced intra-articular fractures of the glenohumeral joint were treated with open reduction and internal fixation from March 1993 to February 1997. This paper reports the results of treating 11 displaced intra­articular fractures of the glenoid by open reduction and internal fixation. There were 10 men and one woman and the fractures were classified according to Ideberg : Type Ⅰa(4), Type Ⅱ(3), Type Ⅲ(1), Type IV(1), Type Va(1), and Type Vc(1).

• Journal of Environmental Impact Assessment
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• v.6 no.2
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• pp.93-102
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• 1997

Acid rain below pH 5.6 is responsible for 40% of annual precipitation in Korea and it is more serious especially in major cites. Because of that, it is urgent to make measures to reduce the emission of $SO_2$, one of the major air pollutants causing acid rain. The national total emission of $SO_2$ in 1994 was estimated as 1.6 million tons. The $SO_2$ emission in 2020, is expected to increase up to 3.2 million tons, about 2 times that of 1994 under Business-As-Usual scenario. We could take various $SO_2$ reduction measures such as installing desulfurization facilities, the supply of low-sulfur oil and clean fuel(LNG), energy savings, upgrading of production process. However, it is necessary to check the economic feasibility and the attainability to reduction target with a dynamic optimization mode, "Global 2100 Model". The cost-benefit analyses for the measures using the revised "Global 2100 Model" clearly revealed that the desulfurization facilities should be introduced to reduce the $SO_2$ concentration to 0.01 ppm with fuel substitution. If the introduction of desulfurization facilities is delayed, We can not attain the goal of Ministry of Environment before the year of 2012, even in the case that almost all the fuels would be substituted with LNG.

• Journal of the Korea Institute of Building Construction
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• v.2 no.2
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• pp.145-150
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• 2002

The hydration of cement paste occurs when the cement is miked with water. During the hydration, hydration heat causes the thermal stress depending on the site of concrete and the cement content. Especially in the high-strength concrete, we must give care to the concrete due to its large cement content. In this study conduction calorimeter and concrete insulation hydration heat meter were used to investigation the hydration heat characteristics of cement and concrete. To reduce hydration heat of high-strength concrete, several types of replacement of fly-ash and blast-furnace slag powder were used in this experiment. As a result of this study, it was found that hydration heat of high-strength concrete was reduced by replacement of fly-ash and blast-furnace slag powder. In case of high-strength concrete using blast-furnace slag powder, the max-heat arrival time was delayed but an effect of heat reduction was lower than a case of high-strength concrete using fly-ash, because it was considered that the heat-dependence property of blast-furnace slag powder was higher than that of fly-ash.