• Journal of Life Science
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• v.18 no.6
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• pp.764-769
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• 2008

Mutations in the human connexin 32 (Cx32) gene are responsible for X-linked Charcot-Marie-Tooth (CMTX) disease. Although over 300 different mutations have been identified the detailed molecular etiology of CMTX disease is poorly understood. Several studies reported that connexin membrane channels share most biophysical properties with their parental gap junction channels. In this study, two connexin mutant membrane channels (one mutant channel called the M34T channel in which the methionine residue at the $34^{th}$ position of the Cx32 protein is replaced with threonine residue and the other mutant channel called the T86C channel in which the threonine residue at the $86^{th}$ position is replaced with cysteine residue) associated with CMTX mutations were characterized at the single-channel level instead of using mutant gap junction channels. The biophysical properties of the M34T channel were very similar to those of the gap junction channel formed by M34T mutation. In addition, the mutant membrane channel study revealed the reversal of the gating polarity, the loss of fast gating and the gain of slow gating. The T86C channel also behaves like its parental wild type Cx32 membrane channel. Taken together, these results suggest that a study using connexin membrane channels is useful to characterize CMTX mutants.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.1-10
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• 2012

This paper presents an experimental result and suggests the confinement effect of headed cross tie in reinforced concrete(RC) columns subjected to cycling horizontal loads under constant axial load. Five RC columns specimens were manufactured, taking confined type of transverse reinforcement, whether or not using cross tie, end detail of cross tie (hooked or headed), and axial stress in column as major variables, Cyclic horizontal load applied to the columns under constant axial stress and the effect of cross tie to structural capacity of column was evaluated from the test. The column without cross tie failed showing bending deformation of hoop with crack in core concrete at low horizontal load while the column with cross tie showed quite improved strength and ductility by suppressing bending deformation of hoop as well as buckling of longitudinal bar at once even after crack in core concrete. At high lateral displacement, the column with hooked cross tie showed the failure pattern loosing the confining force of cross tie since the $90^{\circ}$ hooked part of cross tie was stretched out and the cracked core concrete lumps were came off. However, the column with headed cross tie showed very stable behavior since the head of cross tie effectively confined the hoop and longitudinal bars even at high lateral displacement.

• Journal of Food Hygiene and Safety
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• v.22 no.1
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• pp.1-14
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• 2007

The term, "food safety", has traditionally been viewed as a practical science aimed at assuring the prevention acute illnesses caused by biological microorganisms, and only to a minor extent, chronic diseases cause by chronic low level exposures to natural and synthetic chemicals or pollutants. "food safety" meant to prevent microbiological agents/toxins in/on foods, due to contamination any where from "farm to Fork", from causing acute health effects, especially to the young, immune-compromised, genetically-predisposed and elderly. However, today a broader view must also include the fact that diet, perse (nutrients, vitamins/minerals, calories), as well as low level toxins and pollutant or supplemented synthetic chemicals, can alter gene expressions of stem/progenitor/terminally-differentiated cells, leading to chronic inflammation and other mal-functions that could lead to diseases such as cancer, diabetes, atherogenesis and possibly reproductive and neurological disorders. Understanding of the mechanisms by which natural or synthetic chemical toxins/toxicants, in/on food, interact with the pathogenesis of acute and chronic diseases, should lead to a "systems" approach to "food safety". Clearly, the interactions of diet/food with the genetic background, gender, and developmental state of the individual, together with (a) interactions of other endogenous/exogenous chemicals/drugs; (b) the specific biology of the cells being affected; (c) the mechanisms by which the presence or absence of toxins/toxicants and nutrients work to cause toxicities; and (d) how those mechanisms affect the pathogenesis of acute and/or chronic diseases, must be integrated into a "system" approach. Mechanisms of how toxins/toxicants cause cellular toxicities, such as mutagenesis; cytotoxicity and altered gene expression, must take into account (a) irreversible or reversal changes caused by these toxins or toxicants; (b)concepts of thresholds or no-thresholds of action; and (c) concepts of differential effects on stem cells, progenitor cells and terminally differentiated cells in different organs. This brief Commentary tries to illustrate this complex interaction between what is on/in foods with one disease, namely cancer. Since the understanding of cancer, while still incomplete, can shed light on the multiple ways that toxins/toxicants, as well as dietary modulation of nutrients/vitamins/metals/ calories, can either enhance or reduce the risk to cancer. In particular, diets that alter the embryo-fetal micro-environment might dramatically alter disease formation later in life. In effect "food safety" can not be assessed without understanding how food could be 'toxic', or how that mechanism of toxicity interacts with the pathogenesis of any disease.

• Journal of the Korean Geotechnical Society
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• v.33 no.12
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• pp.7-20
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• 2017

In this study, effects of grain size distribution on the shear strength and rheological properties are investigated for coarse- and fine-grained soils by using direct shear apparatus. Shear strengths are estimated for fine-grained soils with the maximum particle size of 0.075 mm and coarse-grained soils with the maximum particle size of 0.425 mm and fine contents of 17% prepared at dry and liquid limit states. The direct shear tests are conducted under the relatively slow shear velocity, which corresponds to the reactivated landslide or debris flow after collapse according to the landslide classification. In addition, for the evaluation of rheological properties, residual shear strengths for both fine- and coarsegrained soils prepared under liquid limit states are obtained by multiple reversal shear tests under three shear velocities. From the relationship between residual shear strengths and shear rates, Bingham plastic viscosity and yield stress are estimated. The direct shear tests show that cohesions of fine-grained soil are greater than those of coarse-grained soil at both dry and liquid limit states. However, internal friction angles of fine-grained soil are smaller than those of coarse-grained soil. In case of rheological parameters, the plastic viscosity and yield stress of fine-grained soils are greater than those of coarse-grained soils. This study may be effectively used for the prediction of the reactivated landslide or debris flow after collapse.

• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.64-86
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• 1994

The authors have transplanted periodontally involved roots which had been root planed into healthy and periodontally involved extraction sockets, and studied the root resorption patterns as well as its effect on new bone formation and wound healing. Alveolar bone around mandibular premolars of 6 adult dogs has been surgically removed, followed by ligation of orthodontic elastic wires for 8 weeks inducing chronic periodontal disease. After removing the crown portions, roots were extracted, and notches were made on the root surfaces discriminating healthy and periodontally involved areas using burs. Controls and experimental groups were divided as follows. Control I : Transplantation of periodontally involved root into healthy extraction sockets. Control II : Transplantation of periodontally involved root into diseased extraction sockets. Experimental group I : Transplantation of root planed roots into healthy extraction sockets. Experimental group II : Transplantation of root planed roots into diseased extraction sockets. Extraction sockets were sutured after transplantations, completely submerging the roots. Healing progress was histologically observed at 2nd, 8th, 12th, and 20th weeks, and the results were as follows ; 1. No inflammation or infection within the extraction sockets had been observed in all groups throughout the experimental period. 2. Reversal lines were observed at week 2 in all groups, clearly discriminating socket walls and new bone, and numerous blood vessels were observed in the new bone trabeculae. 3. Experimental groups showed markedly less root resorption compared to the controls at week 2, but as time progressed, severe resorptions were present in all groups. 4. Localized areas of new bone ankylosis were observed, and the rest of the areas showed collagen fiber insertion with new bone formation at its periphery. 5. No clear differences were found in healing and alveolar bone regeneration between healthy and diseased extraction sockets. 6. The amount of root resorption and ankylosis had increased up to week 8 and 12, showing ankylosis of new bone and the roots. However, no further increase in ankylosis was observed at week 20. 7. Most of the cementum on healthy roots was directly ankylosed to new bone at week, 2, and were gradually resorbed and replaced by new bone thereafter. These results appear to indicate that root planing may inhibit early root resorption of transplanted roots, but gradual replacement by alveolar bone and collagen fibers eventually occur. Condition of the roots or presence of disease in extraction sockets do not appear to make marked differences in alveolar bone regeneration process.

• Journal of Aquaculture
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• v.10 no.2
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• pp.179-187
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• 1997

Early development growth and sexual phenomena of the hybrid between male spotted flounder (Verasper variegatus) and female olive flounder (Paralichthys olivaceus) were investigated. The hybrid produced was newly called the "Bumnupchi" in Korean name, "Mottled flounder" in English name. Fertilization rate, hatching rate and early survival rate of the mottled flounder were 56.9~72.3%, 86.7~92.5% and 89.1~96.0%, respectively. At 50th day and 240th day after hatching, they were 2.1$\pm0.2cm\;and\;22.9\pm2.1cm\;in\;total\;length, \;0.10\pm0.002g\;and\;179.0\pm38.5g$ in body weight, respectively. Eye position of the mottled flounder was mixed with both dextral (77.7%) and sinistral type (22.3%). Gonads were differentiated into ovarian type and testis type at 80th day after hatching, and its ratio was 1:1 (P>0.05). Most Gonads seemed to be sterile without having germ cell, whereas only 3.6% of investigated indiciduals turned out to have oocytes in the gonad. When the induction of sex reversal were attempted by daily oral administration of $17\beta$-methyltestosterone (0.5mg/kg fish) andestradiol-17$17\beta$(0.5mg/kg fish)from 40th to 100th day after hatching, both testis and ovary type were induced 81.9% and 87.7% of each hormone-treated fish, respectively.fish, respectively.

• Korea journal of population studies
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• v.34 no.1
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• pp.159-178
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• 2011

Korea has been widely recognized as the most successful country for reversal of the rise in sex ratio at birth (from the mid-1980s to the mid-1990s) in a short period of time. However, unusually high sex ratios at birth are still observed in most regions as parity increases. Given that imbalanced sex ratios at high birth orders are mostly due to son-selective abortion, it still remains questionable whether son-selective reproductive behavior has vanished in Korea. The main purpose of this study is to analyze the pattern of changing trends and socioeconomic differentials in sex ratio at birth. Micro-data from birth registration for 2009 are utilized. Attention is focused on analyzing sex ratios at birth in Youngnam region according to age of mother, parity, educational attainment of parents, and occupation of parents. A series of simulations are also conducted in this paper to show how prenatal sex screening and son-selective abortion have affected the level of sex ratio at birth for years 1994, 2005 and 2009.

• Geophysics and Geophysical Exploration
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• v.9 no.2
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• pp.139-147
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• 2006

We had conducted a numerical modeling to investigate seismic properties of gas hydrate with field parameters acquired over the East sea in 1998. We used a 2-D staggered grid finite difference method to generate synthetic elastic seismograms for multi-channel seismic survey, OBC (Ocean Bottom Cable) survey and VCS (Vertical Cable Seismic) survey. The results of this study showed that the method using staggered grid yielded stable results and could be used to seismic imaging. We could find out the high amplitude anomaly and the phase reversal phenomenon of reflection wave at interface between the gas hydrate layer and free gas layer such a BSR (Bottom Simulating Reflector) which is the evidence for existence of gas hydrate in seismic reflection data. And we computed the reflection coefficients at the incident angles corresponding to offset distance with the synthetic seismograms. The reflection coefficients acquired from the numerical modeling were nearly consistent with the reflection coefficient computed by Shuey's equation.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.85-98
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• 2009

The tau-p inversion algorithm is widely employed to generate starting models with most computer programs, which implement refraction tomography. This algorithm emphasises the vertical resolution of many layers, and as a result, it frequently fails to detect even large lateral variations in seismic velocities, such as the decreases which are indicative of shear zones. This study demonstrates the failure of the tau-p inversion algorithm to detect or define a major shear zone which is 50m or 10 stations wide. Furthermore, the majority of refraction tomography programs parameterise the seismic velocities within each layer with vertical velocity gradients. By contrast, the Generalized Reciprocal Method (GRM) inversion algorithms emphasise the lateral resolution of individual layers. This study demonstrates the successful detection and definition of the 50m wide shear zone with the GRM inversion algorithms. The existence of the shear zone is confirmed by a 2D analysis of the head wave amplitudes and by numerous closely spaced orthogonal seismic profiles carried out as part of a later 3D refraction investigation. Furthermore, an analysis of the shot record amplitudes indicates that a reversal in the seismic velocities, rather than vertical velocity gradients, occurs in the weathered layers. The major conclusion reached in this study is that while all seismic refraction operations should aim to provide as accurate depth estimates as is practical, those which emphasise the lateral resolution of individual layers generate more useful results for geotechnical and environmental applications. The advantages of the improved lateral resolution are obtained with 2D traverses in which the structural features can be recognised from the magnitudes of the variations in the seismic velocities. Furthermore, the spatial patterns obtained with 3D investigations facilitate the recognition of structural features such as faults which do not display any intrinsic variation or 'signature' in seismic velocities.

• Journal of Ginseng Research
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• v.38 no.1
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• pp.1-7
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• 2014

Background: Although ginsenosides such as Rg1, Rb1 and Rg3 have shown promise as potential nutraceuticals for cognitive impairment, their use has been limited due to high production cost and low potency. In particular, the process of extracting pure Rg3 from ginseng is laborious and expensive. Methods: We described the methods in preparing ginseol k-g3, an Rg3-enriched fraction, and evaluated its effects on scopolamine-induced memory impairment in mice. Results: Ginseol k-g3 (25-200 mg/kg) significantly reversed scopolamine-induced cognitive impairment in the passive avoidance, but not in Y-maze testing. Ginseol k-g3 (50 and 200 mg/kg) improved escape latency in training trials and increased swimming times within the target zone of the Morris water maze. The effect of ginseol k-g3 on the water maze task was more potent than that of Rg3 or Red ginseng. Acute or subchronic (6 d) treatment of ginseol k-g3 did not alter normal locomotor activity of mice in an open field. Ginseol k-g3 did not inhibit acetylcholinesterase activity, unlike donezepil, an acetylcholinesterase inhibitor. Rg3 enrichment through the ginseol k-g3 fraction enhanced the efficacy of Rg3 in scopolamine-induced memory impairment in mice as demonstrated in the Morris water maze task. Conclusion: The effects of ginseol k-g3 in ameliorating scopolamine-induced memory impairment in the passive avoidance and Morris water maze tests indicate its specific influence on reference or long-term memory. The mechanism underlying the reversal of scopolamine-induced amnesia by ginseol k-g3 is not yet known, but is not related to anticholinesterase-like activity.