Radiocarbon (14C) in natural samples undergoes changes due to variations in atmospheric CO2 resulting from anthropogenic activities. To analyze the variation of the 14C ratio in atmospheric CO2, deciduous tree leaves were collected in Gyeongju, a popular tourist city in South Korea. Leaf samples were collected from Prunus subg. Cerasus trees at five different sampling points throughout the city over 3 years (2018, 2020, and 2021). The 14C data of the samples were categorized into three groups (downtown, rural, and tourist sites) and analyzed for variations among the different years. The 14C ratio at downtown sites was stable after 2018, the rural site ratio increased between 2018 and 2020 and then decreased between 2020 and 2021, and the tourist site ratio increased after 2018. We theorize that the increased 14C ratio at the tourist site was caused by a decrease in tourism after 2018.

It has not been well established whether dietary folate intake reduces the risk of diabetes development. We aimed to clarify the prospective association between dietary folate intake and type 2 diabetes (T2D) risk among 7333 Korean adults aged 40 years or older who were included in the Multi-Rural Communities Cohort. Dietary folate intake was estimated from all 106 food items listed on a FFQ, not including folate intake from supplements. Two different measurements of dietary folate intake were used: the baseline consumption and the average consumption from baseline until just before the end of follow-up. The association between folate intake and T2D risk was determined through a modified Poisson regression model with a robust error estimator controlling for potential confounders. For 29 745 person years, 319 cases of diabetes were ascertained. In multivariable analyses, dietary folate intake was inversely associated with risk of T2D for women, not for men. For women, the incidence rate ratio of diabetes in the third tertile compared with the first tertile was 0·57 (95 % CI 0·38–0·87, Pfor trend=0·0085) in the baseline consumption model and 0·64 (95 % CI 0·43–0·95, Pfor trend=0·0244) in the average consumption model. These inverse associations was found in both normal fasting blood glucose group and impaired fasting glucose group among women. Among non-users of multinutrients and vitamin supplements, the significant inverse association remained. Thus, higher dietary intake of folate is prospectively associated with lower risk of diabetes for women.

The Sewol ferry disaster is one of the most tragic events in Korea’s modern history. Among the 476 people on board, which included Danwon High School students (324) and teachers (14), 304 passengers died in the disaster (295 recovered corpses and 9 missing) and 172 survived. Of the rescued survivors, 72 were attending Danwon High School, located in Ansan City, and residing in a residence nearby. Because the students were young, emotionally susceptible adolescents, both the government and the parents requested the students be grouped together at a single hospital capable of appropriate psychiatric care. Korea University Ansan Hospital was the logical choice, as the only third-tier university-grade hospital with the necessary faculty and facilities within the residential area of the families of the students. We report the experiences and the lessons learned from the processes of preparing for and managing the surviving young students as a community-based hospital. (Disaster Med Public Health Preparedness. 2017;11:389–393)

A 31-year-old patient previously underwent a Mustard operation presented with palpitations. Atrial tachycardia and paroxysmal atrial fibrillation were documented on the surface electrocardiogram. Under the guidance of a three-dimensional electroanatomic mapping system, ablation of the isolated left-sided pulmonary vein and a cavo-tricuspid isthmus-dependent intra-atrial macro re-entry circuit eliminated atrial tachycardia and paroxysmal atrial fibrillation without the recurrence of atrial tachyarrhythmia.

Blackberry is a fruiting berry species with very high nutrient contents. With the recent increasing consumer demand for blackberries, new sources of germplasm and breeding techniques are required to improve blackberry production. This study was carried out to evaluate the genetic diversity (GD) and relationship among 55 blackberry (Rubus fruticosus) mutants derived from γ-ray treatment (52 lines) and N-methyl-N′-nitrosourea (MNU) treatment (three lines) using an inter-simple sequence repeat marker. A total of 18 bands were amplified with an average of 3.6 bands per primer. Among them, eight bands were identified to be polymorphic with a rate of 44.4%. In addition, the GD information content values were highest in the 60 Gy treatment population and the GD values were higher in the γ-ray treatment populations than in the MNU treatment population. According to a cluster analysis, all the mutant lines can be classified into five categories, and the genetic distance was greatest between the 80 Gy-irradiated population and other populations. These results indicate that mutant lines have high GD and can be effectively utilized for improving blackberry breeding.

Mutation breeding techniques have been used to induce new genetic variations and improve agronomic traits in soybean. In Korea, the Korea Atomic Energy Research Institute (KAERI) has unique radiation facilities to induce plant mutations and has been conducting soybean mutation breeding programmes since the mid-1960s. Until now, the KAERI has developed five soybean mutant cultivars exhibiting early maturity, high yield and seed-coat colour change. In this paper, we review these five mutant cultivars in terms of how to successfully induce unique agronomic characteristics through mutation breeding programmes. A number of induced mutants exhibiting null lipoxygenase enzymes, altered protein patterns or Kunitz trypsin inhibitor activity could serve as genetic resources for the genetic analysis of target genes, and one mutant population has been developed for a reverse genetic study.

The liquid phase plasma reduction method has been applied to prepare silver nanoparticles from a solution of silver nitrate (AgNO3) using a bipolar pulsed electrical discharge system. The excited states of atomic silver, hydrogen and oxygen as well as the molecular bands of hydroxyl radicals were detected in the emission spectra. As the discharge duration increased up to 10 min, silver particle peaks produced by surface plasmon absorption were observed around 430 nm. Both the particle size and the particle numbers were observed to increase with the length of the plasma treatment time and with the initial AgNO3 concentration. Spherical nanoparticles of about 5–20 nm in size were obtained with the discharging time of 5 min, whereas aggregates of nanoparticles of about 10–50 nm in size were mainly produced with the discharging time of 20 min. The cationic surfactant of cetyltrimethylammonium bromide (CTAB) added with the CTAB/AgNO3 molar ratio of 30% was shown to inhibit nanoparticle aggregation.

Here we report an epoch-making simple fabrication for wrinkle formation. The present wrinkle formation process is a solution for controlling the area, shape and direction of wrinkle area by forming wrinkles on the liquid state polydimethylsiloxane directly exposed to sputtered metal particles in the low vacuum plasma chamber in various vacuum states and deposition conditions. Also the process allows us to make extremely flexible metal thin film electrode with approved adhesion. These bring us possibilities of actual electrical and biological applications.

The levels and distribution of polychlorinated biphenyl (PCB) congeners were analysed in fourteen soil and eight lichen (Usnea aurantiaco-atra) samples from King George Island, West Antarctica. A total of 32 PCB congeners were found in five soil samples collected in 2006, and the mean concentration of total PCBs was 20.4 pg g-1 dry weight (range, 8.0−33.8 pg g-1 dry weight). The most abundant PCB isomers in soil samples were di-, tri-, and penta-CBs, which accounted for more than 75% of the total residues. Twelve dioxin-like PCBs were also detected in nine soil and eight lichen samples, and the levels of dioxin-like PCBs were 5-fold higher in lichens than in soil. PCBs were detected at very low levels in most soil and lichen samples. The highest congener concentrations were found for PCB 118 (6.63 and 21.93 pg g-1 in soil and lichen, respectively) among dioxin-like PCBs. PCB levels in air samples were highly correlated with those in soil and lichen samples, as were PCB levels in soil and lichen samples collected at the same site. Long-range atmospheric transport is thought to be the main source of PCBs on King George Island. However, PCB levels in soil and lichen samples were also apparently influenced by local sources of PCBs.

A systematic study on the effect of sputtering deposition parameters on material properties of Al doped ZnO (ZnO:Al) films prepared by an in-line rf magnetron sputtering and on surface morphology of the films after wet etching process was carried out. For application to silicon thin film solar cells as a front electrode, the as-deposited films were surface-textured by a dilute HCl solution to improve the light scattering properties such as haze and angle resolved distribution of scattered light on the film surfaces. The microstructure of as-deposited films is affected significantly by the working pressure and film compactness decreases with increasing working pressure from 1.5 mTorr to 10 mTorr. High quality ZnO:Al films with electrical resistivity of 4.25 × 10-4 Ω cm and optical transmittance of 80% in a visible range are obtained at low working pressure of 1.5 mTorr and substrate temperature of 100℃. Crater-like surface morphologies are observed on the textured ZnO:Al films after wet etching. The size and shape of craters are closely dependent on the microstructure and film compactness of as-deposited films. Haze values of the textured ZnO:Al films are improved in a whole wavelength of 300 – 1100 nm compared to commercial SnO2:F films (Asahi U type) and incident light on the textured films is scattered effectively with 30° angle.

The objective of this study was to determine developmental pattern and cell allocation to the inner cell mass and trophectoderm in haploid and diploid embryos following parthenogenetic activation. In vitro matured porcine oocytes were activated by ethanol treatment and cultured in the presence or absence of cytochalasin B for 5h. The oocytes were then cultured in the NCSU23 for 9 days. The combined treatment with cytochalasin B following ethanol treatment did not increase (p >0.1) the incidence of activation. The incidence of development to the blastocyst stage was higher (p <0.05) in the combined treatments of ethanol and cytochalasin B as compared with ethanol treatment alone. The percentage of oocytes with two female pronuclei was higher (p < 0.01) in oocytes treated with cytochalasin B than that in ethanol treatment alone. Treatment with both ethanol and cytochalasin B increased (p <0.01) the incidence of diploid chromosome spread over just the ethanol treatment alone. The average numbers of total cells and inner cell mass were significantly reduced (p <0.05) in the ethanol treatment alone as compared with the combined cytochalasin B and ethanol treatment. These results suggested that the ploidy may affect blastocoele formation and cell allocation to inner cell mass and trophectoderm in the pig.

We have investigated the shift of threshold voltage in the a-Si:H TFT due to the various negative pulse width stress. The drain bias dependent threshold voltage shift in the pulsed stress of a-Si:H TFT for AMOLED backplane is also measured and analyzed. When a positive gate and drain bias is applied to a-Si:H TFT (W/L = 200/4 Ým), VTH of a-Si:H TFT is increased during the stress time due to the defect state creation and charge trapping. VTH of a-Si:H TFT is increased from 1.645V to 2.53V (δVTH=0.885V) after the DC gate bias stress of VGS=15V, VDS=0V for 20,000sec. When the pulsed negative bias stress is applied to the gate electrode of the current driving a-Si:H TFT with the drain bias, VTH shift is considerably reduced due to the hole trapping into the gate insulator during the stress. When a negative pulse width is 16msec (pulse of 60Hz), the VTH is increased form 1.594V to 2.195V (δVTH=0.601V). When a negative pulse width increases from 16msec to 5sec without drain bias (VDS=0V), VTH is increased from 1.615V to 2.055V (δVTH=0.44V). When a drain bias is increased from 0V to 15V, VTH is slightly decreased from 1.58V to 1.529V (δVTH=-0.051V) due to large (-30V) VGD (VG=-15V, VD=15V) bias, while it is increased from 1.66V to 2.078V (δVTH=0.418V) width DC gate bias stress of VGS=15V, VDS=15V for 20,000sec.

To detect biological events, biosensors require a transducer part where specific biomolecular binding events at a bioreceptor part is converted to measurable quantitative signals. Currently, most of biosensors adopt a fluorescent or radioactive probing technique as a transducer. However, such approaches require expensive and sophisticated analysis procedures with laboratory-based equipment.

In this work, we propose a novel method for optically detecting hybridization results in a deoxyribonucleic acid (DNA) chip using an anchoring transition of liquid crystal (LC) alignment. To investigate the effects of structural changes of DNA on the LC alignment, we used a functional substrate on which single-stranded oligonucleotide DNA (ssDNA) was selectively immobilized to a Biotin Chip substrate. In our experiment, we used a 19-mer oligoDNA or p53 tumor suppressor as a bioreceptor and its complementary partner oligoDNA as a target material.

Before hybridization, surface nematic LC (NLC) molecules on the immobilized ssDNAs are homeotropically aligned by a steric interaction between the freely penetrated NLC molecules and the ssDNA. After hybridization, the penetration of the NLC molecules is hindered by the double strand DNA (dsDNA) due to their increased packing density. Such an interface condition makes the surface ordering of the NLC molecules very weak, as a result, the NLC in the bulk has a planar inhomogeneous orientation. Although hybridization events of the DNA and the subsequent molecular interaction between the immobilized DNA and the NLC molecules takes place within a layer whose thickness is in the tens of nm, such binding events can be communicated to the NLC bulk beyond a distance of tens of μm though the long-range elastic deformation of the NLC molecules. Thus, the hybridization event is converted to amplified optical signals via birefringent nature of the NLC between crossed polarizers. Our NLC-based DNA chip array showed that the extinction ratio of transmitted light depending on the hybridization results was approximately four, which could be read by the naked eye. Since such anchoring behaviors on the immobilized DNA are very similar to those on the conventional amphiphilic homeotropic surfactant of LCs, it is expected that quantitative analysis of hybridization events can be explored with our simple system.

Single-crystalline with good optical properties aligned ZnO nanonails were grown on steel alloy substrate without the use of metal catalyst or additives by the thermal evaporation process using high purity metallic zinc powder and oxygen as source materials for zinc and oxygen, respectively. Detailed morphological studies by FESEM revealed that the obtained nanonails are grown in a high density over the whole substrate surface and are exhibiting perfect hexagonal-shaped caps. The diameters of the nanonails at their tops and bases are ranges from 120∼160nm and 50∼70 nm, respectively. The detailed structural characterizations confirmed that the synthesized nanostructures are single-crystalline and grown along the c-axis direction. Raman scattering and room-temperature photoluminescence studies demonstrated the wurtzite hexagonal phase and good optical properties, respectively for the grown nanonails.