• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.397-403
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• 2015

Heavy metals reduce the photosynthetic efficiency and disrupt metabolic reactions in a concentration-dependent manner. Moreover, by replacing the metal ions in metalloproteins that use essential metal ions, such as Cu, Zn, Mn, and Fe, as co-factors, heavy metals ultimately lead to the formation of reactive oxygen species (ROS). These, in turn, cause destruction of the cell membrane through lipid peroxidation, and eventually cause the plant to necrosis. Given the aforementioned factors, this study was aimed to understand the physiological responses of rice to cadmium (Cd) and arsenic (As) toxicity and the effect of essential metal ions on homeostasis. In order to confirm the level of physiological inhibition caused by heavy metal toxicity, hydroponically grown rice (Oryza sativa L. cv. Dongjin) plants were exposed with $0-50{\mu}M$ cadmium (Cd, $CdCl_2$) and arsenic (As, $NaAsO_2$) at 3-leaf stage, and then investigated malondialdehyde (MDA) contents after 7 days of the treatment. With increasing concentrations of Cd and As, the MDA content in leaf blade and root increased with a consistent trend. At 14 days after treatment with $30{\mu}M$ Cd and As, plant height showed no significant difference between Cd and As, with an identical reduction. However, As caused a greater decline than Cd for shoot fresh weight, dry weight, and water content. The largest amounts of Cd and As were found in the roots and also observed a large amount of transport to the leaf sheath. Interestingly, in terms of Cd transfer to the shoot parts of the plant, it was only transported to upper leaf blades, and we did not detect any Cd in lower leaf blades. However, As was transferred to a greater level in lower leaf blades than in upper leaf blades. In the roots, Cd inhibited Zn absorption, while As inhibited Cu uptake. Furthermore, in the leaf sheath, while Cd and As treatments caused no change in Cu homeostasis, they had an antagonist effect on the absorption of Zn. Finally, in both upper and lower leaf blades, Cd and As toxicity was found to inhibit absorption of both Cu and Zn. Based on these results, it would be considered that heavy metal toxicity causes an increase in lipid peroxidation. This, in turn, leads to damage to the conductive tissue connecting the roots, leaf sheath, and leaf blades, which results in a reduction in water content and causes several physiological alterations. Furthermore, by disrupting homeostasis of the essential metal ions, Cu and Zn, this causes complete heavy metal toxicity.

• Journal of Life Science
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• v.21 no.5
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• pp.647-655
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• 2011

The neurotoxicity of aggregated amyloid ${\beta}$ ($A{\beta}$) has been implicated as a critical cause in the pathogenesis of Alzheimer's disease (AD). It can cause neurotoxicity in AD by evoking a cascade of apoptosis to neuron. Here, we investigated the neuroprotective effects of cilostazol, which acts as a phosphodiesterase III inhibitor, on $A{\beta}_{25-35}$-induced cytotoxicity in mouse neuronal cells and cognitive decline in the C57BL/6J AD mouse model via peroxisome proliferator-activated receptor (PPAR)-${\gamma}$ activation. $A{\beta}_{25-35}$ significantly reduced cell viability and increased the number of apoptotic-like cells. Cilostazol treatment recovered cells from $A{\beta}$-induced cell death as well as rosiglitazone, a PPAR-${\gamma}$ activator. These effects were suppressed by GW9662, an antagonist of PPAR-${\gamma}$ activity, indicative of a PPAR-${\gamma}$-mediated signaling. In addition, cilostazol and rosiglitazone also restored PPAR-${\gamma}$ activity levels that had been altered as a result of $A{\beta}_{25-35}$ treatment, which were antagonized by GW9662. Furthermore, cilostazol also markedly decreased the number of apoptotic-like cells and decreased the Bax/Bcl-2 ratio. Intracerebroventricular injection of $A{\beta}_{25-35}$ in C57BL/6J mice resulted in impaired cognitive function. Oral administration of cilostazol (20 mg/kg) for 2 weeks before $A{\beta}_{25-35}$ injection and once a day for 4 weeks post-surgery almost completely prevented the $A{\beta}_{25-35}$-induced cognitive deficits, as did rosiglitazone. Taken together, our findings suggest that cilostazol could attenuate $A{\beta}_{25-35}$-induced neuronal cell injury and apoptosis as well as promote the survival of neuronal cells, subsequently improving cognitive decline in AD, partly because of PPAR-${\gamma}$ activation. The phosphodiesterase III inhibitor cilostazol may be the basis of a novel strategy for the therapy of AD.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.375-383
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• 2023

To determine the cause of the population decline in Gobiobotia naktongensis, substrate preference and burying behaviour were investigated in this study. In general, the species was shown to prefer a substrate size of 1 mm or less, depending on the flow. In addition, the burying depth varied according to the size of the fish and increased with a decrease in water temperature. Our findings showed that the main cause of the population reduction was the physical changes in the substrate structure due to the dams or barrages construction. Notably, the accumulation of silt and mud in the substrate upon the formation of an upstream lentic water region for structural construction and bed armouring caused by scouring and reduced downstream inflow of fine sediment were deterministic in the fish habitat changes, causing problems in burying. As sand substrate structure is critical for the survival and inhabitation of psammophilous species, efficient strategies should be developed with proper habitat management to reduce the anthropogenic damage

• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.22-34
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• 2013

As construction project has been becoming larger, specialized and complicated, it is important to utilize a lot of information that is made by diverse participants. Especially this information is mainly produced in construction site that plays a leading role in construction project. The problem of information exchange between participants of construction site causes decline of construction productivity. So as to resolve this problem, there is a many interest in BIM(Building Information Modeling) that makes and manages a necessary data during building life cycle. But in Korea construction industry, applying BIM in construction phase is less active than in design phase. Through studying previous research, this study classify the main cause of failure related to information exchange in framework construction. And by interviewing expert, it draw a work that is possible to apply BIM. Next through analyzing framework construction site that is applied with BIM, this study proposes specific information flow model for supporting work by BIM.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.249-252
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• 1993

Water culture studies were conducted in the greenhouse with mulberry plants to investigate the nutrient uptake, especially Zn and Cu, under high phosphrous concentration. Mulberry plants were grown with five phosphorus levels(0, 0.2, 0.5, 2.0, 5.0 mM). Leaves and roots were analyzed for water content, total nitrogen, P, K, Ca, Mg, Fe, Mn, total Zn, soluble Zn, Cu, Cl, $NO_3HPO_4$ and $SO_4$. Dry matter increased upto 2.0mM phosphorus level, and then decreased. Water content, total nitrogen, P, K, and Fe in leaves increased with increasing phosphorus level. Total Zn content in leaves showed little change, whereas soluble Zn increased and Cu decreased with increasing phosphorus level. With increasing phosphous level. $SO_4$ and Cl decreased and then sharply increased above 2.0mM phosphorus. Lower uptake of Cu and higher uptake of $SO_4$ and Cl suggest a cause of mulberry yield decline with high accumulation of soil phosphorus.

• Journal of Cadastre & Land InformatiX
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• v.46 no.2
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• pp.57-77
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• 2016

This paper analysis spatial correlation applying commercial activating factor and categories clusters among have homogeneity in garosu street which are rising commercial issue in residential district. Based on this research we can draw several implications. Firstly, Garosu street are forming unique space around fassion feature like clothes and food and Beverage stores are supporting main functions. secondly, in terms of utilization of semi-public space in individual buildings, main Street are using display goods and put product.Also restaurants and cafes are using public space as terrace seats. These results mean principal road emphasizes displaying and passing but inner road emphasizes taking a break and staying. Third, repetitive action between high rising vacancy and new building cause negative effects city decline and lossing identity. So residents and merchants should cooperate and make communities for sustainable district.

• Journal of The Korean Association For Science Education
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• v.24 no.6
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• pp.1256-1271
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• 2004

The importance of science attitudes is more increasing in science education. Science attitudes may influence students' attainment, consistency and quality of classwork as well as their later views of science education and scientific occupations. According to the international comparative researches and longitudinal studies on Korean students' science attitudes, it has shown that the more grade, the less science attitude. This research was survey the science attitudes and learning environment variables, and then make a inquiry that causes of decline of science attitudes. To study this purpose, the participating students in this study will be selected from 3th to 11th grade. 6,925 participants were administered 3 times in questionnaires of science attitudes and learning environment variables during a year. The result of this study showed that science attitude got low after June. Science attitude was changed from 4th grade to 8th grade students. Science attitude much more decrease second semester than first semester, high school students' science attitude fell much. It was experience about science that cause the biggest effect in science attitude and other learning environment variables influence in science attitude change. Learning environment variables made different influence from students of increased and declined science attitude. As category that influence in science attitude, in elementary school were gender, area and grade, in middle school were grade and area, and in high school was area.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.48-67
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• 2021

Plant species exhibit current characteristics as a result of interactions with environmental conditions. The plants of Viola sp. have selected chasmogamous flowers with vigorous vegetative propagation or development of cleistogamous flowers as an adaptation strategy. Viola websteri is distributed on the Korean peninsula and the eastern part of Jilin Province, China. The center and edge of the distribution are expected to exhibit different population-dynamics. It is necessary to investigate the cause of its current limited distribution even though V. websteri has a mixed-mating strategy. Firstly, We examined the vegetation environment of habitats and evaluated its characteristics. Growth characteristics were examined through plant phenology. We then evaluated the population structure, characteristics of chasmogamous flowers, and productivity of cleistogamous flowers. Moreover, we compared population sizes between 2014 and 2018. Most habitats were located in deciduous broadleaf mixed forests adjacent to valleys. V. websteri produced chasmogamous flowers with self-incompatibility in April-May and cleistogamous flowers in June-September. The cleistogamous flower production is a strategy ensuring seed production under uncertain environmental fluctuations; these were approximately twice as numerous as chasmogamous flowers. The population structure was distinguished into stable and very unstable regions. There were sites where the population experienced a sharp decline in the 2018 compared to that of 2014. This large decline was found in the edge populations. The habitats had different microsites depending on the natural disturbances of drought and the matrix constituting the habitat, thus supporting various plants. Ensuring the production of seeds through cleistogamous flowers, it was determined that rapid seedling re-establishment and population replenishment were possible when the natural disturbance factor was removed. Environmental factors did not equally affect all populations or individuals. Therefore, it was expected that it would be able to persisted in a long time, despite the rapid decrease in the number of individuals in the population regionally. Local extinction and re-establishment are likely to repeat according to environmental change. We propose the additional population investigation based on this works are required. We also suggest a need to assess the long-term population dynamics and the genetic characteristics of chasmogamous flowers and cleistogamous flowers to establish and implement effective conservation strategies.

• Journal of The Korean Association For Science Education
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• v.42 no.3
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• pp.325-340
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• 2022

This study attempts to analyze the causes of low affective achievement of elementary, middle, and high school students in Korea in science. To this end, a total of 27 students, three to four students per grade, were interviewed by grade from the fourth grade of elementary school to the first grade of high school, and a total of nine teachers were interviewed by school level. In the interview, related questions were asked in five sub-areas of the 'Indicators of Positive Experiences about Science': 'Science Academic Emotion', 'Science-Related Self-Concept', 'Science Learning Motivation', 'Science-Related Career Aspiration', and 'Science-Related Attitude'. Interview contents were recorded, transcribed, and categorized. As a result of examining the causes of low science academic emotion, it was found that students experienced negative emotions when experiments are not carried out properly, scientific theories and terms are difficult, and recording the inquiry results is burdensome. In addition, students responded that science-related self-concept changed negatively due to poor science grades, difficult scientific terms, and a large amount of learning. The reasons for the decline in science learning motivation were the lack of awareness of relationship between science class content and daily life, difficulty in science class content, poor science grades, and lack of relevance to one's interest or career path. The main reason for the decline in science-related career aspirations was that they feel their career path was not related to science, and due to poor science performance. Science-related attitudes changed negatively due to difficulties in science classes or negative feelings about science classes, and high school students recognized the ambivalence of science on society. Based on the results of the interview, support for experiments and basic science education, improvement of elementary school supplementary textbook 'experiment & observation', development of teaching and learning materials, and provision of science-related career information were proposed.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.9
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• pp.4517-4525
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• 2016

Background: Sperm DNA damage is underlying aetiology of poor implantation and pregnancy rates but also affects health of offspring and may also result in denovo mutations in germ line and post fertilization. This may result in complex diseases, polygenic disorders and childhood cancers. Childhood cancer like retinoblastoma (RB) is more prevalent in developing countries and the incidence of RB has increased more than three fold in India in the last decade. Recent studies have documented increased incidence of cancers in children born to fathers who consume alcohol in excess and tobacco or who were conceived by assisted conception. The aetiology of childhood cancer and increased disease burden in these children is lin ked to oxidative stress (OS) and oxidative DNA damage( ODD) in sperm of their fathers. Though several antioxidants are in use to combat oxidative stress, the effect of majority of these formulations on DNA is not known. Yoga and meditation cause significant decline in OS and ODD and aid in regulating OS levels such that reactive oxygen speues meditated signal transduction, gene expression and several other physiological functions are not disrupted. Thus, this study aimed to analyze sperm ODD as a possible etiological factor in childhood cancer and role of simple life style interventions like yoga and meditation in significantly decreasing seminal oxidative stress and oxidative DNA damage and thereby decreasing incidence of childhood cancers. Materials and Methods: A total of 131 fathers of children with RB (non-familial sporadic heritable) and 50 controls (fathers of healthy children) were recruited at a tertiary center in India. Sperm parameters as per WHO 2010 guidelines and reactive oxygen species (ROS), DNA fragmentation index (DFI), 8-hydroxy-2'-deoxy guanosine (8-OHdG) and telomere length were estimated at day 0, and after 3 and 6 months of intervention. We also examined the compliance with yoga and meditation practice and smoking status at each follow-up. Results: The seminal mean ROS levels (p<0.05), sperm DFI (p<0.001), 8-OHdG (p<0.01) levels were significantly higher in fathers of children with RB, as compared to controls and the relative mean telomere length in the sperm was shorter. Levels of ROS were significantly reduced in tobacco users (p<0.05) as well as in alcoholics (p<0.05) after intervention. DFI reduced significantly (p<0.05) after 6 months of yoga and meditation practice in all groups. The levels of oxidative DNA damage marker 8-OHdG were reduced significantly after 3 months (p<0.05) and 6 months (p<0.05) of practice. Conclusions: Our results suggest that OS and ODD DNA may contribute to the development of childhood cancer. This may be due to accumulation of oxidized mutagenic base 8OHdG, and elevated MDA levels which results in MDA dimers which are also mutagenic, aberrant methylation pattern, altered gene expression which affect cell proliferation and survival through activation of transcription factors. Increased mt DNA mutations and aberrant repair of mt and nuclear DNA due to highly truncatred DNA repair mechanisms all contribute to sperm genome hypermutability and persistant oxidative DNA damage. Oxidative stress is also associated with genome wide hypomethylation, telomere shortening and mitochondrial dysfunction leading to genome hypermutability and instability. To the best of our knowledge, this is the first study to report decline in OS and ODD and improvement in sperm DNA integrity following adoption of meditation and yoga based life style modification.This may reduce disease burden in next generation and reduce incidence of childhood cancers.