• Journal of the Korean institute of surface engineering
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• v.36 no.6
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• pp.491-499
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• 2003

Copper-based leadframe sheets were oxidized in a hot alkaline solution to form brown-oxide layer on the surface and molded with epoxy molding compound (EMC). The brown-oxide-coated leadframe/EMC joints were machined to form sandwiched double-cantilever beam (SDCB) specimens and sandwiched Brazil-nut (SBN) specimens for the purpose of measuring the fracture toughness of leadframe/EMC interfaces. The SDCB and the SBN specimens were designed to measure the fracture toughness of the leadframe/EMC interfaces under nearly mode-I loading and mixed-mode (mode I ＋ mode II) loading conditions, respectively. Fracture surfaces were analyzed by various equipment such as glancing-angle XRD, SEM, AES, EDS and AFM to elucidate failure path. Results showed that failure occurred irregularly in the SDCB specimens, and oxidation time of 2 minutes divided the types of irregular failures into two classes. The failure in the SBN specimens was quite different from that in the SDCB specimens. The failure path in the SBN specimens was not dependent on the phase angle as well as the distance from tips of pre-cracks.

• Journal of Korea Foundry Society
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• v.20 no.2
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• pp.116-121
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• 2000

Interfacial reaction and mechanical properties between Sn-Zn-X ternary alloys(X : 3wt.%In, 4wt.%Bi) and Cu-substrate were studied. Cu/solder joints were subjected to aging treatments for up to 50days to see interfacial reaction at $100^{\circ}C$ and then were examined changes of microstructure and interfacial compound by optical microscopy, SEM and EDS. Cu/solder joints were aged to 30days and then loaded to failure at cross head speed of 0.3 mm $min^{-1}$ to measure tensile strength. According to the results of the solderability test, additions of In and Bi in the Sn-9wt.%Zn solder improve the wetting characteristics of the alloy and lower the melting temperature. Through the EDS and XRD analysis of Cu/Sn-9wt.%Zn solder joint, it was concluded that the intermetallic compound was the ${\gamma}-Cu_5Zn_8$ phase. Cu-Zn intermetallics at Cu/solder interfaces played an important role in both the microstructure evolution and failure of solder joints. Cu/solder joint strength was decreased by aging treatment, and those phenomenon was closely related to the thickening of intermetallic layer at Cu/solder joints.

• Neonatal Medicine
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• v.28 no.2
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• pp.89-93
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• 2021

Nemaline myopathy is a genetically heterogeneous neuromuscular disorder and one of the most common congenital myopathies. The clinical manifestations usually vary depending on the age of onset. Neonatal nemaline myopathy has the worst prognosis, primarily due to respiratory failure. Several genes associated with nemaline myopathy have been identified, including NEB, ACTA1, TPM3, TPM2, TNNT1, CFL2, KBTBD13, KLHL40, KLHL41, LMOD3, and KBTBD13. Here, we report a neonatal Korean female patient with nemaline myopathy carrying compound heterozygous mutations in the gene KLHL40 as revealed using next generation sequencing (NGS). The patient presented with postnatal cyanosis, respiratory failure, dysphagia, and hypotonia just after birth. To identify the genetic cause underlying the neonatal myopathy, NGS-based gene panel sequencing was performed. Compound heterozygous pathogenic variants were detected in KLHL40: c.[1405G>T];[1582G>A] (p. [Gly469cys];[Glu528Lys]). NGS allows quick and accurate diagnosis at a lower cost compared to traditional serial single gene sequencing, which is greatly advantageous in genetically heterogeneous disorders such as myopathies. Rapid diagnosis will facilitate efficient and timely genetic counseling, prediction of disease prognosis, and establishment of treatments.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.22 no.5
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• pp.479-486
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• 2019

Progressive familial intrahepatic cholestasis (PFIC) is a group of severe genetic disorders, inherited in an autosomal recessive manner, causing cholestasis of hepatocellular origin, later progressing to biliary cirrhosis and liver failure. This is the first report of PFIC type 1 with novel compound heterozygous mutations in Korea. The patient was presented with intrahepatic cholestasis, a normal level of serum ${\gamma}-glutamyl$ transferase, steatorrhea, and growth failure. Genetic testing of this patient revealed novel compound heterozygous mutations (p.Glu585Ter and p.Leu749Pro) in the ATP8B1 gene. After a liver transplantation at age 19 months, the patient developed severe post-transplant steatohepatitis.

• Journal of The Korean Society of Clinical Toxicology
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• v.7 no.1
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• pp.32-37
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• 2009

Formic acid or formate is a common industrial compound used in the production of ensilage, disinfectants, decalcifying agents and mainly as a precursor in industrial chemical synthesis. It is also a well-known toxic metabolite produced in methanol poisoning. Thus, formate is a potential source of both accidental and deliberate poisoning. Very few reports have been published thus far, on the toxicology of direct formic acid poisoning. Here, we report a case of a 74-year-old man without a history of depression, who ingested about 30 gm of formic acid. The patient presented with profound high anion gap metabolic acidosis, acute renal failure and esophageal stricture. The patient was successfully treated with hemodialysis and supportive measures. But permanent esophageal stricture was complicated by formic acid burns in the gastrointestinal tract. We discuss the pathophysiology and treatment of this case.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.195-202
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• 2003

In this study, failure mechanisms of Au stud bumps/ACF flip chip joints were investigated underhigh current stressing condition. For the determination of allowable currents, I-V tests were performed on flip chip joints, and applied currents were measured as high as almost 4.2Amps $(4.42\times10^4\;Amp/cm^2)$. Degradation of flip chip joints was observed by in-situ monitoring of Au stud bumps-Al pads contact resistance. All failures, defined at infinite resistance, occurred at upward electron flow (from PCB pads to chip pads) applied bumps (UEB). However, failure did not occur at downward electron flow applied bumps (DEB). Only several $m\Omega$ contact resistance increased because of Au-Al intermetallic compound (IMC) growth. This polarity effect of Au stud bumps was different from that of solder bumps, and the mechanism was investigated by the calculation of chemical and electrical atomic flux. According to SEM and EDS results, major IMC phase was $Au_5Al_2$, and crack propagated along the interface between Au stud bump and IMC resulting in electrical failures at UEB. Therefore. failure mechanisms at Au stud bump/ACF flip chip Joint undo high current density condition are: 1) crack propagation, accompanied with Au-Al IMC growth. reduces contact area resulting in contact resistance increase; and 2) the polarity effect, depending on the direction of electrons. induces and accelerates the interfacial failure at UEBs.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.1103-1110
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• 2020

In this study, a segmented model with Upside-Down bathtub shaped failure intensity for a repairable system are proposed under the assumption that the occurrences of the failures of a repairable system follow the Non-Homogeneous Poisson Process. The proposed segmented model is the compound model of S-PLP and LIP (Segmented Power Law Process and Logistic Intensity Process), that fits the separate failure intensity functions on each segment of time interval. The maximum likelihood estimation is used for estimating the parameters of the S-PLP and LIP model. The case study of system A shows that the S-PLP and LIP model fits better than the other models when compared by AICc (Akaike Information Criterion corrected) and MSE (Mean Squared Error). And it also implies that the S-PLP and LIP model can be useful for explaining the failure intensities of similar systems.

• Childhood Kidney Diseases
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• v.26 no.1
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• pp.63-67
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• 2022

Nephrocalcinosis often occurs in infants and is caused by excessive calcium or vitamin D supplementation, neonatal primary hyperparathyroidism, and genetic disorders. Idiopathic infantile hypercalcemia (IIH), a rare cause of nephrocalcinosis, results from genetic defects in CYP24A1 or SLC34A1. Mutations in CYP24A1, which encodes 25-hydroxyvitamin D 24-hydroxylase, disrupt active vitamin D degradation. IIH clinically manifests as failure to thrive and hypercalcemia within the first year of life and usually remits spontaneously. Herein, we present a case of IIH wih CYP24A1 mutations. An 11-month-old girl visited our hospital with incidental hypercalcemia. She showed failure to thrive, and her oral intake had decreased over time since the age of 6 months. Her initial serum parathyroid hormone level was low, 25-OH vitamin D and 1,25(OH)₂ vitamin D levels were normal, and renal ultrasonography showed bilateral nephrocalcinosis. Whole-exome sequencing revealed compound heterozygous variants in CYP24A1 (NM_000782.4:c.376C>T [p.Pro126Ser] and c.1310C>A [p.Pro437His]). Although her hypercalcemia and poor oral intake spontaneously resolved in approximately 8 months, we suggested that her nephrocalcinosis and renal function be regularly checked in consideration of potential asymptomatic renal damage. Hypercalcemia caused by IIH should be suspected in infants with severe nephrocalcinosis, especially when presenting with failure to thrive.

• Archives of Pharmacal Research
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• v.28 no.1
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• pp.81-86
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• 2005

The hepatoprotective effects of chalcone derivatives were evaluated in D-galactosamine/lipopolysaccharide (D-GaIN/LPS)-induced fulminant hepatic failure in mouse. Thirteen chalcone derivatives were synthesized for study and their hepatoprotective effects were evaluated by assessing aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in serum. Chalcone preparations were injected into mice at 12 hand 1 h before intraperitoneal injection of D-GaIN/LPS. After abdominal administration, changes in AST and ALT between the control and treated groups were observed. Ten of the synthesized chalcone derivatives exhibited inhibitory effects on D-GaIN/LPS-induced levels of AST and ALT in mice. Compounds 2, 3, 8, 9, and 12 markedly reduced serum AST and ALT at 8 h, inhibited hepatocyte necrosis and showed significant hepatoprotective activities. The activity of compound 3 was compared with the bifendate (DDB) through oral administration. Compound 3 showed much higher inhibitory effects than bifendate for decreasing AST and ALT activity. The results indicate that compound 3 has strong hepatoprotective activity through suppression of tumor necrosis factor­alpha (TNF-alpha) preduction, reduction of the histological change in the liver, and attenuated of hepatocyte apoptosis confirmed by DNA fragmentation assay.

• Carbon letters
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• v.10 no.3
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• pp.190-197
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• 2009

Various silanes, amino silane, vinyl silane, sulfur silane (TESPD), and ZS (TESPD/zinc soap complex), are added into chlorinated isobutylene-isoprene copolymer (CIIR)/soft clay/carbon black (CB) and CIIR/hard clay/CB compounds and they are investigated with respect to the vulcanization characteristics, the processability, and the mechanical properties. Comparing hard clay and soft clay filled compounds, hard clay (Suprex) filled system shows a higher die C tear than the soft clay (GK) filled one. The other properties (Mooney, extrusion torque/pressure, torque rise ($M_H-M_L$), modulus at 300%) are close to each other. Among various silanes, the ZS treated hard clay (Suprex) compound shows the highest mechanical property following hard clay(S)/vinyl silane(V) and soft clay(GK)/vinyl silane(V) compounds. The TESPD and the ZS effectively helps a formation of a strong 3-dimensional network structure between silica and CIIR via coupling reaction due to bifunctional nature of TESPD. In addition to that, the ZS added compounds show both a better processability and mechanical properties compared to the S2 ones at low concentration due to improved compatibility between zinc soap and CIIR matrix. Only the ZS added compound shows both improved processabilities (Mooney, Extrusion torque-& pressure) and improved mechanical properties (degree of crosslinking, elongation modulus, tear, and fatigue to failure counts) on both CIIR/hard clay/CB and CIIR/soft clay/CB compounds.