• Korean Journal of Poultry Science
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• v.21 no.3
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• pp.157-168
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• 1994

This study was carried out to elucidate the time course variation of vitamin $D_{3}$ (V$D_{3}$) and 25-hydroxyvitamin $D_{3}$ [25(OH)$D_{3}$] contents in the liver and skeleton of 3-wk old broiler chicks when treated with different UV irradiation procedure. Day-old Hubbard chicks were fed vitamin D deficient diet for 3 wk and exposed to medium wave ultraviolet(UVB) light with different irradiation procedures. Procedure I was 30 min continuous irradiation(O.204 mJ /$cm^{2}$) and Procedure II was three seperate 10 min irradiation with 12 h intervals, and Procedure III was three seperate 10 min irradiation with 24 h intervals. The liver and skeleton samples were collected at 10 different times between 0000~2400 h after the last irradiation. The V$D_{3}$ and 25(OH)$D_{3}$ fractions wereseparated by Sep-Pak silica cartridge and the concentrations were determined by normal phase HPLC. The mean content of V$D_{3}$ in the liver of the birds treated by Procedure II was 6.68 ng /g, which was higher than 5.60 and 5.30 ng /g from Procedure I and Ill, respectively(P<.O5). With regard to the effect of elapsed time after UVB irradiation on the V$D_{3}$ concentration of the liver, 96 h treatment showed the highest value(13.08 ng/g)(P<.05). There was a significant(P$D_{3}$ were significantly(P$D_{3}$ in the skeleton of tibia and femur, there were no significant differences among Procedure I, II and III, but significant differences were found among those from various elapsed time after irradiation, The highest value was shown at 96 h(O.99 ng /g) treatment, and interaction between irradiation procedure and elapsed time was not significant. With regard to the mean content of 25(OH)$D_{3}$ in bone, the Procedure II(18.79 ng /g) and III(17.73 ng /g) showed higher values than Procedure I did (P<.05), and the 12 h elapsed time showed the highest value(31.17 ng /g) among 10 treatments (P<.05), however, there was no significant interaction between exposing procedure and elapsed time. In conclusion, the Procedure II would he more desirable than Procedure I or III to produce more V$D_{3}$ and 25(OH)$D_{3}$ in the liver and skeleton of birds by exposing to the UVB light. Also, it was verified that 25(OH)$D_{3}$ increases more quickly than V$D_{3}$ in both tissues tested and is utilized more quickly to recover from the rickets of chicks.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.3
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• pp.443-452
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• 1994

This study describes the effects of novel1, 25-dihydroxyvitamin D$_3$ analong[1,25(OH)$_2$-16ene-23yne-26, 27-F6-D$_3$] on proliferation of the human histiocytic lymphoma cell line U937 in vitro. We also examined the expression of c-myc oncogene in U937 cells was apparently inhibited to 62% and 87% of the control level after 4 days in the presence of 10-8M and 10-7 M of this analog, respectively. This compound morpholgically and functionally differentiated U937 cells to nonocyte-macrophage phenotype showing the increase of adherence ability to surface and a decrease of N/C ratio in Giemsa staining . Especially, nonspecific esterase activity which is a marker of cell differentiation to monocyte-macrophage was positive, and production of the positive stained cells increased in a dose dependent fashion . The expression of c-myc oncogene by 1, 25(OH)$_2$D$_3$ analog(10-7 M) was reduced by 60% at the mRNA level as determined by Northern blotting. The effects of this novel analog on cell proliferation and cell differentiation may open op new therapeutic strategies for human disorders such as psoriassis and may provide a tool to understand the mechanism of action of vitamin D$_3$ seco-steroids in malignancy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.967-973
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• 2003

This paper presents a new predistortion method which injects the 2nd low-frequency intermodulation signal of RF signals into the input bias line of the amplifier. New 2nd intermodulation signal extraction circuit is also proposed. We have shown that this method can suppress the 3rd IM apparently and sometimes do the 5th IM, through mathematical analysis, then confirmed it with simulation and verified it on the desk test. When the input signal CDMA IS-95 lFA is applied, measured ACPR improvements are 25 dBc, 22.5 dBc, and 6 dBc at 0.885 MHz, l.25 MHz and 2.25 MHz offset respectively. Also, when applying the CDMA IS-95 3FA, the measured ACPR improvement is 20 dBc at 0.885 MHz offset.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.69-75
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• 2004

This work proposes an 8b 220 MS/s 230 mW 3-stage pipeline CMOS ADC with on-chip filers for temperature- and power- insensitive voltage references. The proposed RC low-pass filters improve switching noise performance and reduce reference settling time at heavy R & C loads without conventional off-chip large bypass capacitors. The prototype ABC fabricated in a 0.25 um CMOS occupies the active die area of 2.25 $\textrm{mm}^2$ and shows the measured DNL and INL of maximum 0.43 LSB and 0.82 LSB, respectively. The ADC maintains the SNDR of 43 dB and 41 dB up to the 110 MHz input at 200 MS/s and 220 MS/s, respectively, while the SNDR at the 500 MHz input is degraded as much as only 3 dB than the SNDR at the 110 MHz input.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1357-1362
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• 2014

Background: Vitamin D deficiency is a potentially modifiable risk factor that may be targeted for breast cancer (BC) prevention. It may also be related to prognosis after diagnosis and treatment. The aim of our study was to determine the prevalence of vitamin D deficiency as measured by serum 25-hydroxy vitamin D (25-OHD) levels in patients with BC and to evaluate its correlations with life-style and treatments. Materials and Methods: This study included 186 patients with stage 0-III BC treated in our breast center between 2010-2013. The correlation between serum baseline 25-OHD levels and supplement usage, age, menopausal status, diabetes mellitus, usage of bisphosphonates, body-mass index (BMI), season, dressing style, administration of systemic treatments and radiotherapy were investigated. The distribution of serum 25-OHD levels was categorized as deficient (<10ng/ml), insufficient (10-24 ng/ml), and sufficient (25-80 ng/ml). Results: The median age of the patients was 51 years (range: 27-79 years) and 70% of them had deficient/insufficient 25-OHD levels. On univariate analysis, vitamin D deficiency/insufficiency was more common in patients with none or low dose vitamin D supplementation at the baseline, high BMI (${\geq}25$), no bisphosphonate usage, and a conservative dressing style. On multivariate analysis, none or low dose vitamin D supplementation, and decreased sun-exposure due to a conservative dressing style were found as independent factors increasing risk of vitamin D deficiency/insufficiency 28.7 (p=0.002) and 13.4 (p=0.003) fold, respectively. Conclusions: The prevalence of serum 25-OHD deficiency/insufficiency is high in our BC survivors. Vitamin D status should be routinely evaluated for all women, especially those with a conservative dressing style, as part of regular preventive care, and they should take supplemental vitamin D.

• Korean Journal of Optics and Photonics
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• v.23 no.1
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• pp.6-11
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• 2012

A bidirectional TDM-PON link to support 2.5 Gb/s upstream signals of 256 ONUs was considered for an extended transmission distance of 50 km. The power budget of the link was 58 dB for the upstream signal and a SOA was applied as a link extender which had a 25 dB gain. Receiver sensitivity of the upstream signal was -25 dBm for -30 dBm input power to the SOA. When the input power was -10 dBm, pulse overshooting caused by gain transient of the SOA was maximum at 45% and the signal performance degradation gave a power penalty of 1.55 dB for $10^{-12}$ BER. However the penalties diminished rapidly and became negligible as the input power went below -15 dBm. So this input power dynamic range of up to -15 dBm means that it is not positively necessary to use gain control methods for the next generation TDM-PON systems.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.16 no.4
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• pp.254-260
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• 2013

Purpose: Recently, vitamin D insufficiency has increased and has been correlated to growth and puberty in children. This study was conducted to find the prevalence of subclinical vitamin D insufficiency and its influence on school-aged children in Korea. Methods: The subjects of this study were 397 children aged 7 to 15 years who had been tested for 25-OH vitamin D3 among the outpatients of the Department of Pediatrics in Eulji General Hospital from March 2007 to February 2011. Data for age, sex, comorbidities, serum 25-OH vitamin D3, height, weight, body mass index (BMI), and sunlight exposure time were collected before and after 3 months of vitamin D administration, retrospectively. Results: Vitamin D insufficiency was present in 343 (86%) of the subjects. In the vitamin D insufficient group, chronological age was $8.96{\pm}1.72$ years, mean height (z-score [z]) was $0.51{\pm}1.26$, mean BMI (z) was $0.81{\pm}2.20$, and bone age was $10.26{\pm}1.75$ years. In the vitamin D sufficient group, chronological age was $9.61{\pm}1.77$ years, mean height (z) was -$0.66{\pm}0.98$, mean BMI (z) was -$0.01{\pm}1.16$, and bone age was $9.44{\pm}2.12$ years. A paired t-test showed that three months after vitamin D administration, the mean 25-OH vitamin D3 level in the insufficient group increased to $24.38{\pm}10.03$ ng/mL and mean BMI (z) decreased to $0.67{\pm}1.06$. Conclusion: In Korean school-aged children, vitamin D insufficiency were relatively higher and may be closely related with higher BMI. Insufficient rise of the level of vitamin D after supplementation suggest the new supplementation guidelines, especially for Korean children.

• Nutrition Research and Practice
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• v.13 no.2
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• pp.115-125
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• 2019

BACKGROUND/OBJECTIVES: Vitamin D plays an important role in skeletal growth and maintenance and in the prevention of various diseases. We investigated the relationship between vitamin D intake and bone mineral density (BMD) in Korean adults aged ${\geq}50$ years using the 2009 Korea National Health and Nutrition Examination Survey data. SUBJECTS/METHODS: This study was conducted in 1,808 subjects aged ${\geq}50$ years with BMD data in Korea. Dietary vitamin D levels were assessed by the 24-hour recall method. BMD was measured using dual-energy X-ray absorptiometry. We investigated general characteristics and the association between these characteristics, vitamin D status, and BMD. RESULTS: Vitamin D intake was significantly lower in the osteoporosis group among women (P < 0.05). Among all subjects, the higher the serum 25(OH)D concentration, the higher the whole-body total BMD (WBT-BMD), femoral total hip BMD, and femoral neck BMD (P < 0.01). In the serum vitamin D-deficient group of both the total population and women, serum 25(OH)D concentration was associated with WBT-BMD (P < 0.05). Among women with a calcium intake < 537.74 mg/day, BMD of those with a vitamin D intake > $2.51{\mu}g/day$ (average intake of women) was higher than that of women with a vitamin D intake ${\leq}2.51{\mu}g/day$ (P < 0.001). CONCLUSIONS: Korean adults should increase their BMD by increasing serum 25(OH)D concentration. Furthermore, increasing vitamin D intake could improve BMD, especially in Korean women who consume less calcium than the estimated average requirement.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.254-260
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• 2017

The primary goals of this research were to evaluate the impact of diet supplemented with 25-hydroxyvitamin $D_3$ ($Hy{\cdot}D(R)$) on sow's body condition and reproduction performance. A total of sixteen multiparous sows [(Landrace ${\times}$ Yorkshire), average parity = $3.79{\pm}0.32$] and their litters were randomly allotted to 2 treatments to give 8 replicates per treatment. Diet treatments were randomized to receive a non-active (ND) or active 25-hydroxyvitamin $D_3$ (AD) diet (0.36 mg cholecalciferol/g) during pregnancy. The results of this experiment were observed at the gestation of d 58 - 75, d 76 - 95, d 96 - 110, and d 111 - 115. A corn-soybean meal-based diet was formulated to meet or exceed the nutrient requirements recommended by NRC (2012). Results indicated that the sows' farrowing duration was shortened (4.71, 5.38 h), and the average number of mummified fetuses decreased significantly (p < 0.05) in AD treatment compared with ND treatment (0.1, 0.5) while birth weight was significantly (p < 0.05) improved (1.44, 1.18 kg). There were no significant effects on body weight, backfat thickness, and fecal score during the gestation of sows in different phases (p > 0.05). And the total birth, stillbirth, live birth, and survival rates of the litter did not change (p > 0.05). The results of this study suggest that the farrowing duration of sow pigs will be shortened and the number of mummies will be decreased while their litters' body weight may be improved, if fed active 25-hydroxyvitamin $D_3$ (0.36 mg/g) during pregnancy phase.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.4
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• pp.403-412
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• 2021

Purpose: This study aimed to determine the serum 25-hydroxy-vitamin D (25(OH)D) status of breastfed infants less than six months old and their mothers, and factors affecting the status. Methods: This cross-sectional study was done on breastfed, term, Filipino infants less than six months old who were seen at local health centers and clinics in an urban area. The serum 25(OH)D levels of these infants and their mothers were determined, and their demographic data, nutritional status, sun exposure behavior, and maternal vitamin D intake were analyzed for correlation using regression models. Results: Among the 131 infants, 101 (77%) had vitamin D deficiency (VDD), which was defined as having 25(OH)D levels <37.5 nmol/L, and 13 (10%) had vitamin D insufficiency (VDI), with levels >37.5-50 nmol/L. Conversely, maternal VDD with levels <50 nmol/L was seen in 31 (24%) mothers and maternal VDI with levels 50-75 nmol/L, in 63 (48%) mothers. Infant age and maternal 25(OH)D status were independent predictors of infant VDD. Infants less than three months old were found to have a six-time increased risk of infant VDD (p=0.004). Infants who had mothers with VDD had a six-time increased risk, whereas those with maternal VDI had a four-time increased risk of infant VDD (p=0.049 and p=0.020, respectively). Conclusion: Both infant and maternal VDD and VDI were seen to be highly prevalent in this tropical, urban community. Young infants and maternal VDD/VDI independently increased the risk of infant VDD, whereas lack of sun exposure of the mothers increased the risk for maternal VDI.