• Korean Journal of Materials Research
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• v.22 no.1
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• pp.8-15
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• 2012

Silicon-based thin film was prepared at room temperature by an electrochemical deposition method and a feasibility study was conducted for its use as an anode material in a rechargeable lithium battery. The growth of the electrodeposits was mainly concentrated on the surface defects of the Cu substrate while that growth was trivial on the defect-free surface region. Intentional formation of random defects on the substrate by chemical etching led to uniform formation of deposits throughout the surface. The morphology of the electrodeposits reflected first the roughened surface of the substrate, but it became flattened as the deposition time increased, due primarily to the concentration of reduction current on the convex region of the deposits. The electrodeposits proved to be amorphous and to contain chlorine and carbon, together with silicon, indicating that the electrolyte is captured in the deposits during the fabrication process. The silicon in the deposits readily reacted with lithium, but thick deposits resulted in significant reaction overvoltage. The charge efficiency of oxidation (lithiation) to reduction (delithiation) was higher in the relatively thick deposit. This abnormal behavior needs to clarified in view of the thickness dependence of the internal residual stress and the relaxation tendency of the reaction-induced stress due to the porous structure of the deposits and the deposit components other than silicon.

• Environmental Analysis Health and Toxicology
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• v.22 no.3
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• pp.189-196
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• 2007

[ $TiO_2$ ] is widely used because it is non-toxic. Recently, however, nanometer size $TiO_2$ particles (P-25) have been produced and used to increase the photo catalysis efficiency. Nanometer-sized $TiO_2$ is efficient, but due to its small size ($20{\sim}30\;nm$), it can flow into ecosystems and into cells. Thus, it may affect human health. Additionally, $TiO_2$ can produce a second contaminant, OH-radical, which is a health risk for all living organisms during photo degradation reaction. Hence, when nanometer-sized $TiO_2$ flows into natural streams and attaches to living organisms, it will create health risks. We investigated the biological toxicity of this condition in zebrafish embryos. We observed abnormal morphology, hatching rate, and measured the catalase activity to determine anti-oxidation at 100 post fertilization hours. Zebrafish were somewhat affected by $TiO_2$ nanometer sized particles under UV-A (a condition similar to sunlight). Powdered $TiO_2$ is toxic to the zebrafish fly. Even without light, $TiO_2$ particles attached to embryos and flies, having an effect on both.

• Journal of Medicine and Life Science
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• v.18 no.1
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• pp.20-23
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• 2021

Methemoglobin is generated by the oxidation of ferrous iron to ferric iron within a hemoglobin molecule. Methemoglobin is unable to bind and transport oxygen, resulting in methemoglobinemia, which can lead to fatal tissue hypoxia. The most common cause of methemoglobinemia is poisoning by oxidizing agents such as dapsone, benzocaine, and primaquine. However, methemoglobinemia can also be caused by normal dietary sources. We present two cases of methemoglobinemia that developed after a normal diet in two male patients. In this case report, the patients suddenly developed dyspnea and cyanosis after eating the same meal. They had no history of suspected poisoning, such as the use of drugs, exposure to chemicals, or gas inhalation. Their symptoms did not improve even after a high dose of oxygen was administered; further, an abnormal 'oxygen saturation gap' was observed. Because of CO-oximetry, the methemoglobin levels of the patients were 50.0% and 46.6%, respectively. We administered methylene blue (1 mg/kg), and the patients recovered completely without any complications. Emergency physicians should, therefore, be aware that methemoglobinemia can also be caused by normal dietary sources. In addition, if the source and route of contamination are unclear, an epidemiological investigation should be conducted.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.1
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• pp.18-23
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• 2016

Objective: Newborn screening leads to improved treatment and disease outcomes, but false-positive newborn screening results may impact include parental stress and anxiety, perception of child as unhealthy, parent-child relationship dysfunction, and increased infant hospitalizations. The purpose of this study was to investigate of the false positive rates and the causative factors of false positive results in Tandem Mass Spectrometry (TMS) in single center. Methods: Records were reviewed for all 18,872 subjects who were born in Cheill General Hospital, during January 1st, 2012 to December 31st, 2014. 17,292 neonates (91.62%) were tested for tandem mass screening almost in 2-5th day of life. Newborn babies whose first results were abnormal had been tested repeatedly by same methods in 7-14 day. If the results were abnormal again, further evaluation was performed. TMS analysis included data for the 43 disorders screened for using TMS broken down into three categories: fatty acid oxidation disorders, organic acidurias, and aminoacidopathies. The impact of several factors on increased false positive rates was analyzed using a multivariate analysis: time from birth to sample collection, birth weight, birth height, BMI, gender, gestational age, delivery type. Results: Males of the subjects were 8942 (51.7%), female 8350 (48.3%), the mean gestational age was $38.6{\pm}1.7$ weeks, the average birth weight $3,155.6{\pm}502.4g$, the average birth height $49.1{\pm}2.9cm$, and the average BMI $13.0{\pm}3.8(kg/m^2)$. Vaginal delivery cases were 9713 (56.2%), caesarean section 7,579 (43.8%). The average date of the inspection was $2.8{\pm}1.1$ days. 224 cases were identified as TMS positive. All the subjects were false positive (222/17,292, 1.30%) except 2 cases (1 male; benign phenylketonuria and 1 female; Short chain acyl-CoA dehydrogenase deficiency). The false positive rates were 0.61% in fatty acid oxidation disorders, 0.25% in organic acidurias, and 0.45% in aminoacidopathies. In our study, the date of inspection got late, the false positive rates got higher. Because almost the cases of late test date were in treatment in neonatal intensive care unit so their test date was affected by their medical conditions. False positive rate was higher in extreme immaturity${\leq}27$ weeks than newborns of gestational age >27 weeks [OR=6.957 (CI=1.273-38.008), p<0.025] and extremely low birth weight<1,000 g than newborns of birthweight ${\geq}1,000g$ [OR=5.616 (CI=1.134-27.820), p<0.035]. Conclusion: False positive rate of TMS was 1.30% in Cheil General Hospital. Lower gestational age and birth weight impacted on increased false positive rates. Better understanding of factors that influence the reporting of screening tests, and the ability to modify these important factors, may improve the screening process and reduce the need for retesting. of screening tests, and the ability to modify these important factors, may improve the screening process and reduce the need for retesting.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.199-204
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• 2009

Purpose : Seizure associated with fever may indicate the presence of underlying inherited metabolic diseases. The present study was performed to investigate the presence of underlying metabolic diseases in patients with complex febrile seizures, using analyses of urine organic acids. Method : We retrospectively analyzed and compared the results of urine organic acid analysis with routine laboratory findings in 278 patients referred for complex febrile seizure. Results : Of 278 patients, 132 had no abnormal laboratory findings, and 146 patients had at least one of the following abnormal laboratory findings: acidosis (n=58), hyperammonemia (n=55), hypoglycemia (n=21), ketosis (n=12). Twenty-six (19.7 %) of the 132 patients with no abnormal findings and 104 (71.2%) of the 146 patients with statistically significant abnormalities showed abnormalities on the organic acid analysis (P<0.05). Mitochondrial respiratory chain disorders (n=23) were the most common diseases found in the normal routine laboratory group, followed by PDH deficiency (n=2) and ketolytic defect (n=1). In the abnormal routine laboratory group, mitochondrial respiratory chain disorder (n=29) was the most common disease, followed by ketolytic defects (n=27), PDH deficiency (n=9), glutaric aciduria type II (n=9), 3-methylglutaconic aciduria type III (n=6), biotinidase deficiency (n=5), propionic acidemia (n=4), methylmalonic acidemia (n=2), 3-hydroxyisobutyric aciduria (n=2), orotic aciduria (n=2), fatty acid oxidation disorders (n=2), 2-methylbranched chain acyl CoA dehydrogenase deficiency (n=2), 3-methylglutaconic aciduria type I (n=1), maple syrup urine disease (n=1), isovaleric acidemia (n=1), HMG-CoA lyase deficiency (n=1), L-2-hydroxyglutaric aciduria (n=1), and pyruvate carboxylase deficiency (n=1). Conclusion : These findings suggest that urine organic acid analysis should be performed in all patients with complex febrile seizure and other risk factors for early detection of inherited metabolic diseases.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.12
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• pp.105-112
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• 2009

In this paper, we investigated abnormal ESD failure on guard-rings in the smart power IC fabricated with $0.35{\mu}m$ Bipolar-CMOS-DMOS (BCD) technology. Initially, ESD failure occurred below 200 V in the Machine Model (MM) test due to current crowding in the parasitic diode associated with the guard-rings which are generally adopted to prevent latch-up in high voltage devices. Optical Beam Induced Resistance Charge (OBIRCH) and Scanning Electronic Microscope (SEM) were used to find the failure spot and 3-D TCAD was used to verify cause of failure. According to the simulation results, excessive current flows at the comer of the guard-ring isolated by Local Oxidation of Silicon (LOCOS) in the ESD event. Eventually, the ESD failure occurs at that comer of the guard-ring. The modified comer design of the guard-ring is proposed to resolve such ESD failure. The test chips designed by the proposed modification passed MM test over 200 V. Analyzing the test chips statistically, ESD immunity was increased over 20 % in MM mode test. In order to avoid such ESD failure, the automatic method to check the weak point in the guard-ring is also proposed by modifying the Design Rule Check (DRC) used in BCD technology. This DRC was used to check other similar products and 24 errors were found. After correcting the errors, the measured ESD level fulfilled the general industry specification such as HBM 2000 V and MM 200V.

• Journal of the Korean Magnetics Society
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• v.6 no.3
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• pp.158-164
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• 1996

The magnetic and magneto-optical properties of the Tb/Co multilayers as a function of the layer thickness and the ratio of Tb/Co thicknesses were studied. When the thickness of Tb layer was $12{\AA}$, the maximum perpendicular anisotropy energy and the maximum thickness ratio which displays the perpendicular anisotropy were obtained. This result indicated that the Tb-Tb and Co-Co pairs as well as the Tb-Co pairs contribute to the perpendicular anisotropy. The Kerr rotation angle, $({\theta}_k)$ was proportional to the perpendicular anisotropy energy and was inversely proportional to the average spin dispersion angle, $(\alpha)$. The maximum $({\theta}_k)$ of $0.28^{\circ}$ was obtained in the film of $12{\AA}$ Tb and the thickness ratio of 1.55. The abnormal hysteresis loops were appeared during the aging treatment because the coercivity difference between the Co layer and the Tb layer was increased by the preferential oxidation of Tb.

• Molecular & Cellular Toxicology
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• v.4 no.1
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• pp.16-21
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• 2008

Cell death of trophoblast, particularly by abnormal release of physiological nitric oxide (NO) has been known to be a causative factor of pre-eclampsia. In the present study, effects of intracellular calcium increase enhancing the activity of NO synthases (neuronal NO synthase, nNOS in this trophoblast cells) on the cell death were examined in a human placental full-term cell line (HT-1). Furthermore, we analyzed the possible mechanisms underlying the augmentation of $Ca^{++}$-mediated NOS activity mediated by protein kinases like PKC, PKA, or CaM-KII. In experiments for cell toxicity, a calcium ionophore (ionomycin $10{\mu}M$) enhanced cell death confirmed by MTT assay, and increased significantly nNOS activity determined with a hemoglobin oxidation assay. This cell death was partially protected by pre-treatment of 7-nitroindazole (7-NI, $10{\mu}M$ and $100{\mu}M$), a nNOS-specific inhibitor. Additionally, $Ca^{++}$-ionophore -induced increase of nNOS activity also was partially normalized by pre-treatment of specific inhibitors of protein kinases, PKC, PKA or CaM-KII. Therefore, we suggest that an increase of calcium influx, leading to the activation of nNOS activity, which in turn may result in the death of trophoblast cells by involvement of signaling mechanisms of protein kinases.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.12
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• pp.1-9
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• 2003

In this paper, a novel Ni silicide technology with Cobalt interlayer and Titanium Nitride(TiN) capping layer for sub 100 nm CMOS technologies is presented, and the device parameters are characterized. The thermal stability of hi silicide is improved a lot by applying co-interlayer at Ni/Si interface. TiN capping layer is also applied to prevent the abnormal oxidation of NiSi and to provide a smooth silicidc interface. The proposed NiSi structure showed almost same electrical properties such as little variation of sheet resistance, leakage current and drive current even after the post silicidation furnace annealing at $700^{\circ}C$ for 30 min. Therefore, it is confirmed that high thermal robust Ni silicide for the nano CMOS device is achieved by newly proposed Co/Ni/TiN structure.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5205-5210
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• 2015

Background: Acute leukaemia is characterized by fast growth of abnormal clones of haemopoietic precursor cells inside bone marrow leading to undue accumulation in the bone marrow. Acute lymphoblastic leukemia (ALL) is the most common form of childhood cancer. Materials and Methods: The study concerned 50 children diagnosed with ALL (mean age, $8.55{\pm}2.54$) compared to 40 healthy controls (mean age, $8.00{\pm}1.85$). The Hb, serum copper, ceruloplasmin oxidase, advanced oxidation protein products (AOPPs), total antioxidant activity (TAA) and protein were measured in all groups.One proteinous component was isolated by gel filtration chromatography from the precipitate produced by polyethylene glycol. Results: Significantly higher levels of AOPP, copper and decrease in total antioxidant activity were noted in the cases. Statistical analysis also showed a significant increase (p<0.01) in the activity of serum ceruloplasmin oxidase in patients with ALL compared to normal subjects .The maximum velocity (Vmax) and Michaelis constant had values of 104.2 U/L and 11.7 mM, respectively. The ${\Delta}H^*$ values for ceruloplasmin oxidase in ALL patients were positive, confirming the reaction to be endothermic. Conclusions: The results from this study showed a significant increase in AOPP, ceruloplasmine oxidase and decrease in total antioxidant activity .These parameters may play a role in development of DNA damage in childhood patients with acute lymphoblastic leukemia (ALL).The ${\Delta}S^*$ and ${\Delta}G^*$ values were negative, these refer that the reaction of ES formation is spontaneous, but needs energy in a so-called endergonic reaction. Also the negative ${\Delta}S^*$ value of ceruloplasmin oxidase indicates that the complex [$ES^*$] is further modulated through increasing structure arrangement.