• Clinical and Experimental Reproductive Medicine
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• v.21 no.2
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• pp.201-206
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• 1994

Down syndrome is one of the major chromosomal anomalies in Korea. To decrease incidence of Down syndrome, antenatal diagnosis is essential. At present, antenatal diagnosis of Down syndrome is done by karyotyping from chorionic villus sampling, amniocentesis, and cordocentsis. All these methods have some problems such as a risk of abortion, a long waiting time, difficulties in sampling, and so on. The aim of study was to confirm that PCR(Polymerase Chain Reaction) using D21S11 primer could be a diagnostic tool for Down syndrome. PCR using D21S11 primers with $^{32}P$ labeling at 5' end was done in 21 cases of DNA from 21 Trisomy and 20 cases of DNA from normal karyotype. PCR product was running for 10 hours on the 6% polyacrylamide gel under 1,000 V or for 8 hours under 1,500 V. After X-ray film exposure, it was read by densitometry. Normal group showed 1: 1 band or single band. 21 Trisomy group showed 1.3-2: 1 band or 2.3 times of density compared to normal single band or 3 bands. This method gave the result within 24 hours. It can be an useful diagnostic tool to detect 21 Trisomy antenatally, especially in late pregnancy, and in preimplantation diagnosis.

• Korean Parent-Child Health Journal
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• v.3 no.2
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• pp.41-48
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• 2000

The sleep is the most important problem for new parents. However, there were very rare the study about sleep of normal neonates and early infants in Korea. So we attempted pilot survey study of neonates' sleep pattern. The purpose of this study was to investigate the sleep pattern of normal neonates in Seoul and Kyungki area and to provide for basis for nursing intervention for parents of them. The subjects of this study were 37 normal full-term neonates of 2~3weeks of age who were visited by researcher or assistant at postpartum care unit, health care clinic, outpatient clinic located in Seoul and Kyungki area from April 20, 1999 to March 15, 2000. This study was descriptive survey study under the convenient sampling method. The instrument of this study was the NCASA translated by Korean Parent Child Health Academic Association. The collected data were coded as 1/4hour unit, and analyzed by MS Office Excel program. The result of this study were as followed: 1. The mean amount of total sleep was 15.1hours. The mean amount of daytime sleep was 9.5hours. The mean amount of nighttime sleep was 5.7 hours. The mean amount of longest sleep was 2.9hours. The mean amount of shortest sleep was 0.6hour. 2. The mean amount of total activity was 8.9hours. The mean amount of daytime activity was 6.5 hours. The mean amount of nighttime activity was 2.3hours. The frequency of feeding was 10.4 times a day. The frequency of daytime feeding was 7.3 times. The frequency of nighttime feeding was 3.1 times. It is suggested that various subjects and more data according to age, and comparative study among different cultures are needed for further study in the future.

• Journal of Periodontal and Implant Science
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• v.31 no.3
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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.

• International Journal of Safety
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• v.3 no.1
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• pp.27-31
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• 2004

Some of the petroleum products contain benzene which is well known as a confirmed human carcinogen. For example, gasoline products contain benzene ranging up to several percents by weight. High exposures to the benzene and other organic solvents would be likely to occur during intermittent tasks and or processes rather than continuous jobs such as sampling, repair, inspection, and loading/unloading jobs. The work time for these jobs is various. However, most of work time is very short and the representative time interval is 15 minutes. Thus, it is preferable to do exposure assessment for 15 minute time weighted average which is known as a short time exposure level(STEL) by ACGIH rather than for 8-hours TWA. It is particularly significant to the exposure monitoring for benzene since it has been known that the exposure rate plays an important role to provoke the leukemia. Due to the large variations, a number of processes/tasks, the traditional sampling technique for organic solvents with the use of the charcoal and sampling pumps is not appropriate. Limited number of samples can be obtained due to the shortage of sampling pumps. Passive samplers can eliminate these limitations. However, low sampling rates resulted in collection of small amount of the target analysts in the passive samplers. This is originated the nature of passive samplers. Field applications were made with use of passive samplers to compare with the charcoal tube methods for 15 minutes. Gasoline loading processes to the tank lorry trucks at the loading stations in the petroleum products storage area. Good agreements between the results of passive samplers and those of the charcoal tubes were achieved. However, it was found that special cautions were necessary during the analysis at very low concentration levels.

• Korean Parent-Child Health Journal
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• v.3 no.1
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• pp.60-72
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• 2000

Studies are needed to determine the standard norms for sleep/activity patterns in new born baby and there have been no established reports of discrepancy of sleep/activity patterns in new born baby among various races. The purpose of this study is to determine whether the NCASA(Nursing Child Assessment Sleep Activity Record) would be suitable to evaluate and to provide the basic resources for a Korean model of sleep/activity patterns during the new born baby, and to provide a basis for nursing intervention for mothers of new born baby. The subjects of this study were 38 normal new born baby who visited the postpartum care center and two general hospitals located in pusan from January 1 to April 28, 2000. They all agreed to participate in this study. The method of data collection was through convenient sampling. Data were collected through questionnaires including demographic data, birth hi story, and general informations concerning the infant, mother and family. The instrument of this study was the NCASA translated by the Korean parent Child Health Academic Association. The collected data were analysed by mean. standard deviation, frequency, and percentage by use of SPSS/PC. The conclusions obtained from this study are summarized as follows: 1. The mean amount of daytime sleep was 10.23 hours. The mean amount of nighttime sleep was 5.53 hours. The mean amount of total daily sleep was 15.77 hours. The mean of the longest sleep period was 4.49 hours. The mean regularity of daytime sleep was 49.69%. The mean regularity of nighttime sleep was 66.98%. The mean regularity of total daily sleep was 55.81%. The mean frequency of nighttime wakenings was 3.09 times. 2. The mean amount of daytime awake periods was 6.12 hours. The mean amount of nighttime awake periods was 2.11 hours. The mean amount of daily total awake periods was 8.23 hours. The mean of the longest awake periods was 3.76 hours. 3. The mean frequency of daytime feeding was 5.71 times. The mean frequency of nighttime feeding was 2.65 times. The mean frequency of total daily feeding was 8.36 times. The mean frequency regularity of feeding was 62.50%. 4. The mean amount of a mother's day time was 16.36 hours. The mean amount of a mother's night time was 7.64 hours. In conclusion, The new born baby slept more during the daytime compare than nighttime and more active during the daytime. On the other hand. although nighttime sleeping the length of the mother was normal, but sleep was interrupted by the infant over 3 times on average. Therefore this research study will contribute to nursing practice and nursing research by its implication through postnatal educational nursing programs at hospital and nursing intervention programs that would help individual caring of early infant mothers at home.

• Korean Parent-Child Health Journal
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• v.3 no.1
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• pp.46-59
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• 2000

The purpose of this study is to determine whether the NCASA (Nursing Child Assessment Sleep/Activity Record) would be suitable to evaluate and to provide the basic resources for a Korean model of sleep/activity patterns during the first 6 months Korean infants' lives and to provide a basis for nursing intervention for mothers of early infants. The subjects of this study were 94 normal infants from birth to 6 months of age who visited the postpartum care center and two general hospitals located in Pusan from February 1 to April 28, 2000. The method of data collection was through convenient sampling. The instrument of this study was the NCASA translated by the Korean parent Child Health Academic Association. The collected data were analysed by mean, standard deviation, frequency percentage and ANOVA, Post Hoc test by use of SPSS/PC. The conclusions obtained from this study are summarized as follows: 1. The mean amount of daytime sleep was 8.06 hours. The mean amount of nighttime sleep was 6.31 hours. The mean amount of total daily sleep was 14.37 hours. The mean of the longest sleep period was 5.20 hours. The mean regularity of daytime sleep was 25.84%. The mean regularity of nighttime sleep was 77.69%. The mean regularity of total daily sleep was 42.60%. The mean frequency of nighttime wakenings was 2.33 times. 2. The mean amount of daytime activity was 8.25 hours. The mean amount of nighttime activity was 1.39 hours. The mean amount of daily total activity was 9.64 hours. The mean of the longest activity period was 3.80 hours The mean frequency of daytime feeding was 5.69 times. The mean frequency of nighttime feeding was 2.08 times. The mean frequency of total daily feeding was 7.74 times. The mean frequency regularity of feeding was 54.62%. The mean frequency of wakenings was 5.14 times. The mean frequency of crying was 1.90 times. 3. According to an analysis of sleep patterns based on an infant's age, there were some significant differences in the following factors: amount of daytime sleep(p<.001), amount of night time sleep(p<.05), amount of total daily sleep (p<.001), longest sleep period(p<.001), regularity of daytime sleep(p<.001), regularity of nighttime sleep(p<.01), regularity of total daily sleep(p<.001), frequency of nighttime wakenings(p<.001). 4. According to an analysis of activity patterns based on an infant's age, there were some significant differences in the following factors: amount of daytime activity(p<.001), amount of nighttime activity(p<.01), amount of total daily activity(p<.001), longest activity period(p<.05), frequency of nighttime feeding(p<.01), frequency of wakenings(p<.001). 5. The mean amount of a mother's day time was 16.30 hours. The mean amount of a mother's night time was 7.70 hours. In conclusion, the initial irregular sleeping and activity patterns of the early infant became regurized as the infant grew older and estabilished firmer patterns of sleeping and of activity.

• Environmental Analysis Health and Toxicology
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• v.25 no.4
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• pp.295-306
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• 2010

Objectives : This study was undertaken to examine the metabolomic changes due to gender and diurnal variation at sampling time and to identify an appropriate time point for urine sampling in epidemiologic studies using metabolomic profiles. Methods : Urine samples were collected twice a day (morning and afternoon) from 20 healthy Korean adults after fasting for 8 hours. The metabolomic assay was investigated using $^1H$ NMR spectroscopy coupled with the principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The metabolites responsible for differentiation between groups were identified through the loading plot of PLS-DA and quantified using Chenomx NMR Suite with a 600 MHz library. Results : Metabolites responsible for differentiation in gender and sampling time were creatinine, trimethyl anine oxide (TMAO), hippurate, mannitol, citrate and acetoacetate. Dimethylamine showed difference only as a factor of diurnal time. The level of creatinine was higher in men compared to women, and the levels of citrate, TMAO, hippurate, mannitol, and acetoacetate were higher in women compared to men. The levels of creatinine, TMAO, hippurate, dimethylamine and mannitol were higher in the morning rather than the afternoon while those of citrate and acetoacetate were higher in the afternoon rather than the morning. Conclusions : Since urinary metabolomic profiles varied by gender and diurnal cycle, urine sampling should be performed at the same time point for all participants in epidemiologic studies using metabolomic profiles.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.173-186
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• 1999

To utilize diffuse sampling of formaldehyde in air, a new sampler was designed. A glass fiber filter was impegnated with 2,4-dinitrophenylhydrazine(DNP) and phosphoric acid and mounted 37mm cassette. The formaldehyde vapor was sampled in the dynamic chamber and measured by high performance liquid chromatograph and compared with solid sorbent tube. The results were as follows ; 1. The desorption efficiencies of diffusive sampler between 97.0% and 100%. 2. the sampling rate is constant as in $58{\sim}61.8m{\ell}/min$ when sampling times are between 120 and 360 min. 3. There was a significant relationship between concentrations of diffusive samples and active samples with the coefficient of determination(R2) of 0.92. 4. Desorbed amount of formaldehyde diffusive sampler was increased by high relative humidity. 5. Wheth diffusive samplers were stored at room temperature or at refrigerator there was no statistically significant difference in the accuracy of result. 6. When the diffusive samplers, which collected formaldehyde vapor, were exposed to clean air for three hours, there was no significant loss of formaldehyde due to reverse diffusion. In conclusion, this study suggest that developed diffusive samplers will be a reasonable substitute for the solid sorbent tube for sampling formaldehyde and practical comparative study of developed diffusive sampler should be performed at workplaces of manufacturing industry.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.191-199
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• 2002

Pacific oysters Crassostrea gigas (Thunberg) were collected on April, 1999 and March­September, 2000 from Goseung Bay along the southern coast of Korea. The oysters tested cp;;ected from a depth of 0.5-2 m in which they cultured by a long line hanging method. The oxygen consumption rates (OCR) of oysters held under constant temperature and darkness (CC), were determined using an automatic intermittent-flow-respirometer (AIFR). Depending on holding periods after oyster collection, the experiments were divided into two groups: Group 7-d (held to ambient temperature for ca. 7 days) and Group 2l-d (held to ambient temperature for ca. 21 days). The OCR for Group 7-d single oyster displayed two peaks every day under CC, while Group 2l-d single oyster showed one peak every day. It is likely that the rhythmic patterns 02.6-12.8 hours) of the OCR in the Group 7-d single oyster may have been influenced by tidal currents at the sampling site. The rhythmic patterns (24.3-24.7 hours) in the Group 2l-d single oyster may have been shifted from two peaks to one peak each day under CC. The present study concludes that the OCR rhythm of wild oysters in nature is governed by two lunar-day clocks (24.8 hours); one driving one peak and the other driving the second peak. When oysters are subjected to the long-term CC conditions, one of the two-clock systems is depressed or only intermittently becomes active. Jpwever. the OCR rhythms by two to three oysters occurred arrhythmic patterns during the experiments and exhibited some evidence of weak rhythmicity of compared to those of a single oyster. It could be partly due to differences group effects.

• 월간산업보건
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• s.356
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• pp.16-25
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• 2017

Chromium exists at various valences, including elemental, trivalent, and hexavalent chromium, and undergoes reduction-oxidation reactions in the environment. Since hexavalent chromium is known as a human carcinogen, it is most important to evaluate the oxidationreduction characteristics of the hexavalent chromium species. Although hexavalent chromium can be reduced to trivalent state, the detailed information on this in workplace environments is limited. The purpose of this study was to investigate hexavalent chromium reduction in time in various conditions. A pilot chrome plating operation was prepared and operated in a laboratory for this study. There was evidence that the hexavalent chromium was reduced by time after mist generation. The percentage ratio (with 95% confidence intervals in parentheses) of hexavalent chromium to total chromium was almost 100% (99.1 ; 102.3) immediately after mist generation, and was reduced to 87.4% (84.8 ; 89.9) at 1 hour and 81.0% (78.3 ; 83.5) at 2 hours, respectively. Another test indicated that hexavalent chromium collected on PVC filters was also reduced by time after sampling. Hexavalent chromium was reduced to 90.8% (88.2 ; 93.3) at 2 hours after sampling. It also was found that hexavalent chromium was reduced during storage in air. It is recommended that air samples of hexavalent chromium be protected against reduction during storage.