• Clinical and Experimental Pediatrics
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• v.55 no.6
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• pp.206-211
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• 2012

Purpose: The increasing prevalence of breast feeding has led to concerns about vitamin D deficiency (VDD) and iron deficiency anemia (IDA) in children. We evaluated the prevalence of VDD in a population of Korean children with IDA and assessed the risk factors for VDD in these children. Methods: A total of 79 children who were diagnosed with IDA were prospectively surveyed from April 2010 to March 2011. Data were collected by questionnaire, medical assessment, and laboratory tests, including measurement of 25-hydroxyvitamin D (25OHD), hemoglobin, and wrist radiography. Results: The median age was 22 months and 30% of the subjects were female. Over a half of subjects (58%) had subnormal vitamin D level (25OHD<30 ng/mL), and VDD (25OHD<20 ng/mL) was present in 39% of children. There was no difference in serum hemoglobin level between IDA patients with VDD and those without VDD. Most subjects (89%) were currently or had recently been breastfed and almost all subjects (97%) who had VDD received breastfeeding. Children with VDD were more likely to be younger than 2 years, to have been breastfed, and to have been tested in winter or spring. Multivariable analysis indicated seasonal variation was a significant independent risk factor for VDD in our IDA patients. Conclusion: Our results demonstrated that VDD has a high prevalence in Korean children with IDA. Primary care physicians should be aware of the possibility of VDD in children with IDA and should supplement the vitamin D as well as iron.

• Journal of IKEEE
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• v.5 no.2 s.9
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• pp.182-189
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• 2001

Single-pass VDD pacemakers have been used as a result of simple implantation procedures and generally reliable atrial tracking that ensures an A-V sequence pacing. However, there is a controversy over their reliabilities of atrial tracking. As a new sensing method for reliable atrial tracking, a simple automatic pacemaker sensing algorithm was implemented and evaluated to validate its benefits in sensing depolarization waves of Single-pass VDD atrial electrograms. The automatic sensing algorithm had a predetermined sensing dynamic range and the sensitivity level was controlled as 50% of the average of two most recently sensed intrinsic amplitudes. The behavior of the automatic sensing algorithm in the Single-pass VDD atrial electrograms was analyzed and characterized. It was observed that the automatic sensing algorithm was more effective than a conventional fixed threshold method to accurately detect and track p-waves in Single-pass VDD electrograms.

• 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.

• Journal of Nutrition and Health
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• v.46 no.6
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• pp.540-551
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• 2013

Vitamin D deficiency (VDD) is becoming an epidemic and thereby a global health problem. Further, VDD adversely affects calcium metabolism and skeletal health, and is associated with increased risk of several diseases, e.g., autoimmune diseases, several types of cancers, type 2 diabetes mellitus, cardiovascular diseases, infectious diseases, asthma, psoriatic arthritis, and etc. To evaluate the prevalence of VDD in Korea, and then to evaluate the association of several factors with serum 25(OH)D level, the author analyzed the data of 14,456 individuals who were 10 years of age and over from the Fifth Korea National Health and Nutrition Examination Survey 1 & 2 (KNHANES V-1 & 2) conducted by the Korean Centers for Disease Control & Prevention. As a result, among Koreans (age $${\geq_-}$$ 10years), 65.9% of males and 77.7% of females were below optimum blood serum 25(OH)D (20 ng/mL). VDD is more severe in female than in male at all age groups. In addition, the younger generations had less 25(OH)D level than older generations in Korea. The analysis by complex sample general linear model (CSGLM) suggested that blood 25(OH)D concentration was related with gender (p < .001), residence (p = .030), occupation (p < .001), anemia (p < .001) and physical activity (p < .001). In conclusion, VDD is pandemic and it is more severe in younger generations in Korea. Further, from the results by CSGLM, serum 25(OH)D status is closely related with the life style of Koreans.

• Journal of IKEEE
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• v.17 no.3
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• pp.284-293
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• 2013

This paper describes a DC-DC boost converter for thermoelectric energy harvesting. The designed converter boosts the VDD through a start-up block from a low-output voltage of a thermoelectric device and the boosted VDD is used to operate the internal control block. When the VDD reaches a predefined value, a detector circuit makes the start-up block turn off to minimize current consumption. The final boosted VOUT is achieved by alternately operating the DC-DC converter for VDD and the main DC-DC converter for VOUT according to the comparator outputs. Simulation results shows that the designed converter generates 2.65V from an input voltage of 200mV and its maximum power efficiency is 63%. The area of the chip designed using a 0.35um CMOS process is $1.3mm{\times}0.7mm$ including pads.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.6
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• pp.442-446
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• 2003

This paper proposes a new two-stage two-phase VPP charge pump configured in such a manner that body effect and the threshold voltage loss are eliminated. The newly proposed circuit is fabricated using 0.18um triple-well CMOS process and the measurement result shows that the VPP level tracks 3VDD when VDD is above the threshold voltage.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.6
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• pp.664-670
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• 2015

A four-times-VDD switch that supports high and low voltage mode operations is demonstrated in a generic 65 nm logic process. The proposed switch shows the robust operation for supply voltages ranging from VDD to $4{\times}VDD$. A cascaded voltage switch and a voltage doubler based charge pump generate the intermediate supply voltage levels required for the proposed high voltage switch. All the high voltage circuits developed in this work can be implemented using standard logic transistors without being subject to any voltage overstress.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.433-450
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• 2002

The concept of VDD(Virtual Design & Development) based on high performance computing technology is introduced. The whole process of design and development could be carried out in cyber space through VDD technology in which high-precision simulation technology is combined with virtual reality technology. Therefore, time for design and development of a new product can be shorten and quality of product can be also improved. However, efficient simulation technology must be developed and appropriate supercomputing system must be available to realize VDD technology. In this work, several technologies for obtaining cost-effective supercomputing systems for VDD technology are introduced and investigated. The detail informations about optimization technology for PC(Personal Computer) computing, clustering technology, Internet Supercomputing technology, and Piggyback technology are provided and numerical results are also presented.

• Journal of Broadcast Engineering
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• v.14 no.3
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• pp.342-356
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• 2009

This paper presents a vote decision-based deinterlacing scheme for false directional error correction(VDD) to convert interlaced signal into non-interlaced signal using only one fields. The VDD using the vote decision goes through four steps process. The first step extracts regions having doubt of false edge using MM-ELA method. In these regions, the edge direction is decided by the majority vote using upper adjacent pixels's information through the second step. But, we still have undecided directions, which will be decided by the majority vote and the directional average decision at the third step. This step preserves the edge directions and minimizes visual degradation. Finally, the last step interpolates undecided pixels using DOI method which can consider the fine edge direction. Although the VDD with hierarchical structure has a high complexity, it can extract delicate edge compared to other pixel-by-pixel or window-by-window deinterlacing algorithms. Simulation results show that it has significantly improved both the subjective and objective qualities of the reconstructed images.

• Nutrition Research and Practice
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• v.14 no.1
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• pp.12-19
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• 2020

BACKGROUND/OBJECTIVES: Vitamin D is a pleiotropic hormone that affects various body organ systems. We evaluated the prevalence of a vitamin D deficiency (VDD) and its potential role in the clinical condition of critically ill Korean children. SUBJECTS/METHODS: Patients under 18 years old with a 25(OH) vitamin D measurement on the first day of PICU admission were included from among the children admitted to the pediatric intensive care unit (PICU) of our tertiary children's hospital between October 2017 and January 2019. RESULTS: A total of 172 pediatric patients were enrolled. The mean 25(OH) vitamin D level was 17.5 ± 12.8 ng/mL. There was a 65.1% prevalence of VDD (25(OH) vitamin D level < 20 ng/mL). VDD was associated with age at PICU admission, gastrointestinal/hepatobiliary disorders, International Society of Thrombosis and Hemostasis disseminated intravascular coagulation (ISTH DIC) score, pediatric multiple organ dysfunction syndrome (pMODS) score and with several laboratory test findings including hemoglobin, platelet, C-reactive protein, serum albumin, total bilirubin, prothrombin time, and anti-thrombin III levels. Most of these parameters also showed significant linear correlations with the 25(OH) vitamin D level (P < 0.05). However, no statistically meaningful association was found between VDD and other clinical conditions such as the need for a mechanical ventilator, requirement for vasoactive drugs, duration of the PICU and hospital stays, or PICU mortality. CONCLUSION: There is a high prevalence of VDD in critically ill Korean children. There were significant associations between the 25(OH) vitamin D level and gastrointestinal/hepatobiliary disorders, the pMODS score and with coagulation related factors. Further large-scale studies with more specific subgroup analyses are required to more precisely assess the clinical implications of VDD in critically ill pediatric patients.