To better investigate the antioxidative property of thermal treatment yam (Dioscorea batatas DECNE.) in Korea, some established methods were used. 70% Methanol, 70% ethanol and chloroform–methanol (CM, 2:1, v/v) extracts were collected. 70% Methanol extract exhibited stronger antioxidative activity evaluated by ferrous ion chelating activity, NO radical scavenging activity and β-carotene bleaching assays. On the contrary, CM extract was the most effective in inhibiting linoleic acid peroxidation. Yam available in Korea was also analyzed for its bioactive compounds such as lycopene, chlorophyll a, b, tannin, phytic acid and total saponin contents. Total saponin was abundant in thermal treatment, which determined to be 42.52±1.88 mg/g. Based on the results obtained from this study, thermal treatment yam could be used as natural antioxidant source due to its high antioxidant activity and bioactive compound contents.

This paper compared the consistency of the Environment Stress(ES) model and the Potential Risk Assessment Model (PARK model, which was developed based on a Korean mariner risk perception) for the Busan adjacent waterway. Evaluation of accuracy and comparison of these two models have been made by Vessel Traffic Service (VTS) officers in the Busan VTS Centre. The assessment results of Busan waterway show that the PARK model is more consistent than the ES model as follows. (1) The difference between assessment results applying ES model and PARK model with risk degree of VTSOs were 34% and 5% respectively in six typical traffic situations. (2) The assessment using PARK model is more suitable and identical with the VTSOs opinion in his or her duty time.

We report results of the performance evaluation of a new hardware correlator in Korea, the Daejeon correlator, developed by the Korea Astronomy and Space Science Institute (KASI) and the National Astronomical Observatory of Japan (NAOJ). We conduct Very Long Baseline Interferometry (VLBI) observations at 22 GHz with the Korean VLBI Network (KVN) in Korea and the VLBI Exploration of Radio Astrometry (VERA) in Japan, and correlated the aquired data with the Daejeon correlator. For evaluating the performance of the new hardware correlator, we compare the correlation outputs from the Daejeon correlator for KVN observations with those from a software correlator, the Distributed FX (DiFX). We investigate the correlated flux densities and brightness distributions of extragalactic compact radio sources. The comparison of the two correlator outputs shows that they are consistent with each other within < 8%, which is comparable with the amplitude calibration uncertainties of KVN observations at 22 GHz. We also find that the 8% difference in flux density is caused mainly by (a) the difference in the way of fringe phase tracking between the DiFX software correlator and the Daejeon hardware correlator, and (b) an unusual pattern (a double-layer pattern) of the amplitude correlation output from the Daejeon correlator. The visibility amplitude loss by the double-layer pattern is as small as 3%. We conclude that the new hardware correlator produces reasonable correlation outputs for continuum observations, which are consistent with the outputs from the DiFX software correlator.

This study was conducted to elucidate the genetic relationships among native Korean cattle breeds by analyzing genetic variations and distances. Relationships among Hanwoo, Korean brindle, Korean black, Jeju black, and Holstein cattle were evaluated using 15 microsatellite markers. Korean brindle and Korean black cattle had the closest relationship based on the lowest genetic distance being observed between these breeds. A Neighbor-Net tree created using the Reynolds distances indicated that Korean brindle and black cattle formed a group separate from the Hanwoo population. However, an Fst pairwise test revealed that Hanwoo, Korean brindle, and Korean black cattle differed significantly (P <0.01). Moreover, the results of this study confirmed that Jeju black cattle became a separate established breed in Korea through a path different from that of cattle from inland regions, even though it is considered to be a Korean native breed. Overall, the results of our study indicate that Korean brindle and black cattle are indeed native Korean breeds that maintain an endangered status.

The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is a species complex, including at least 24 biotypes which express different ecological and physiological characteristics. B. tabaci is one of the most serious pests in the horticultural crops in worldwide level. B. tabaci infests over 600 plant species and also indirectly damages plants by the honeydew excretion. Moreover, whiteflies transmit more than 100 plant viruses, especially begomoviruses. Tomato yellow leaf curl virus (TYLCV) which infested severely in tomato cultivars is transmitted by the vector insect, B. tabaci. Here, we demonstrated whether gene expression of B. tabaci is regulated by the oral ingestion of dsRNA. Double strand RNA (dsRNA) of heat shock protein 70 gene (hsp70) was produced from cDNA by using the specific primer. Whitefly adults were allowed to ingest sugar solution containing dsRNA for 3 hr in the two-layered parafilm feeding tube. Quantitative realtime PCR showed that whiteflies which ingest hsp70 dsRNA completely knockdown its transcript expression. Whiteflies ingestded dsRNA increased mortality by heat shock but not by cold shock. Further research will focus the role of hsp70 in various environmental stresses against insects.

Recent large scale surveys such as Sloan Digital Sky Survey have produced homogeneous samples of multiple-image gravitationally lensed quasars with well-defined selection effects. Statistical analysis on these can yield independent constraints on cosmological parameters. Here we use the image separation statistics of lensed quasars from Sloan Digital Sky Survey Quasar Lens Search (SQLS) to derive constraints on cosmological parameters. Our analysis does not require knowledge of the magnification bias, which can only be estimated from the detailed knowledge on the quasar luminosity function at all redshifts, and includes the consideration for the bias against small image separation quasars due to selection against faint lens galaxy in the follow-up observations for confirmation. We first use the mean image separation of the lensed quasars as a function of redshift to find that cosmological models with extreme curvature are inconsistent with observed lensed quasars. We then apply the maximum likelihood test to the statistical sample of 16 lensed quasars that have both measured redshift and magnitude of lens galaxy. The likelihood incorporates the probability that the observed image separation is realized given the luminosity of the lens galaxy in the same manner as Im et al. (1997). We find that the 95% confidence range for the cosmological constant (i.e., the vacuum energy density) is 0.72 ≤  ≤ 1.0 for a flat universe. We also find that the equation of state parameter can be consistent with −1 as long as the matter density m . 0.4 (95% confidence range). We conclude that the image separation statistics incorporating the brightness of lens galaxies can provide robust constraints on the cosmological parameters.

The purpose of this study was to examine the effect of three cognitive tasks on gait at a preferred walking speed, and at a fast speed, using dual-task methodology. A total of 29 stroke patients participated in the study. All 29 subjects performed 2 motor tasks (10-meter walk task and timed up and go task each at a preferred and a fast speed) and three cognitive tasks [Stroop, word list generation (WLG), serial subtraction (SS)] under dual-task conditions [cognitive-motor interference (CMI)] in a randomized order. Gait speeds were measured in six different conditions. A repeated-measure analysis of variance was employed to compare the results of the Stroop training, WLG, and SS tasks during preferred and fast walking. A Bonferroni adjustment use for post hoc analysis. The level of statistical significance was set at α=.05. A CMI effect occurred for performance of a 10-meter walking task at two different speed and a cognitive task (p＜.05). Stroop had a significantly greater effect than SS and WLG (p＜.05). The timed up and go task was affected when performed with fast walking speed during Stroop cognitive task (p＜.05), but was not affected if performed with preferred walking speed during a cognitive task (p＞;.05). This study showed that CMI of Stroop can be used as a rehabilitation program for stroke patients.

Light scattering enhancement is widely used to enhance the optical absorption efficiency of dye-sensitized solar cells. In this work, we systematically analyzed the effects of spherical voids distributed as light-scattering centers in photoanode films made of an assembly of zinc oxide nanoparticles. Spherical voids in electrode films were formed using a sacrificial template of polystyrene (PS) spheres. The diameter and volume concentration of these spheres was varied to optimize the efficiency of dye-sensitized solar cells. The effects of film thickness on this efficiency was also examined. Electrochemical impedance spectroscopy was performed to study electron transport in the electrodes. The highest power conversion efficiency of 4.07 % was observed with 12μm film thickness. This relatively low optimum thickness of the electrode film is due to the enhanced light absorption caused by the light scattering centers of voids distributed in the film.

Renal dysplasia is a developmental disorder of the renal parenchyma involving anomalous differentiation. It is characterized by persistent metanephric ducts surrounded by primitive mesenchyme, fetal or immature glomeruli, fetal or immature tubules, interstitial fibrosis, and dysontogenic metaplasia involving tissues such as cartilage. Renal dysplasia has been rarely reported in rats. Here, we observed a small left kidney in a rat used in a short-term repeat toxicity study. The rat showed no clinical signs throughout the study. All parameters, including those reflecting kidney functions, were normal upon hematological examination and urinalysis. Grossly, the kidney was small (5 × 8 mm) and its surface appeared normal. Histological examination revealed that the cortex and medulla were poorly demarcated and contained immature/atrophic glomeruli, immature renal tubules, and mesenchymal cells. The cortex contained immature glomeruli, atrophic glomeruli with cystic dilatation of Bowman’s capsular space, and some atypical tubules. Primitive metanephric tubules in the medulla were larger in diameter than normal collecting ducts, lined by a tall columnar epithelium with pale cytoplasm and basal nucleus, and surrounded by loose mesenchymal cells. Occasional tubules contained pale eosinophilic homogenous material in the lumen. Thus, this was diagnosed as a case of renal dysplasia on the basis of histologic features and is the first reported case of renal dysplasia in Sprague Dawley rats.

Aluminum nitride(AlN) films were grown on the C-face and on the Si-face of (0001) silicon carbide(SiC) substrates using plasma-assisted molecular-beam epitaxy(PA-MBE). This study was focused on first-stage growth manipulation prior to the start of AlN growth. Al pre-exposure, N-plasma pre-exposure, and simultaneous exposure(Al and N-plasma) procedures were used in the investigation. In addition, substrate polarity and, first-stage growth manipulation strongly affected the growth and properties of the AlN films. Al pre-exposure on the C-face and on the Si-face of SiC substrates prior to initiation of the AlN growth resulted in the formation of hexagonal hillocks on the surface. However, crack formation was observed on the C-face of SiC substrates without Al pre-exposure. X-ray rocking-curve measurements revealed that the AlN epilayers grown on the Si-face of the SiC showed relatively lower tilt and twist mosaic than did the epilayers grown on the C-face of the SiC. The results from the investigations reported in this paper indicate that the growth conditions on the Si-face of the SiC without Al pre-exposure was highly preferred to obtain the overall high-quality AlN epilayers formed using PA-MBE.