• Korean Journal of Environmental Biology
• /
• v.40 no.3
• /
• pp.352-362
• /
• 2022

Photosynthesis and respiration of seagrasses are mainly controlled by water temperature. In this study, the photosynthetic physiology and respiratory changes of the Asian surfgrass Phyllospadix japonicus, which is mainly distributed on the eastern and southern coasts of Korea, were investigated in response to changing water temperature (5, 10, 15, 20, 25, and 30℃) by conducting mesocosm experiments. Photosynthetic parameters (maximum photosynthetic rate, P_max; compensation irradiance, I_c; and saturation irradiance, I_k) and respiration rate of surfgrass increased with rising water temperature, whereas photosynthetic efficiency (α) was fairly constant among the water temperature conditions. The P_max and I_k dramatically decreased under the highest water temperature condition (30℃), whereas the I_c and respiration rate increased continuously with the increasing water temperature. Ratios of maximum photosynthetic rates to respiration rates (P_max : R) were highest at 5℃ and declined markedly at higher temperatures with the lowest ratio at 30℃. The minimum requirement of H_sat (the daily period of irradiance-saturated photosynthesis) of P. japonicus was 2.5 hours at 5℃ and 10.6 hours at 30℃ for the positive carbon balance. Because longer H_sat was required for the positive carbon balance of P. japonicus under the increased water temperature, the rising water temperature should have negatively affected the growth, distribution, and survival of P. japonicus on the coast of Korea. Since the temperature in the temperate coastal waters is rising gradually due to global warming, the results of this study could provide insights into surfgrass responses to future severe sea warming and light attenuation.

• Korean Journal of Environmental Agriculture
• /
• v.19 no.4
• /
• pp.294-299
• /
• 2000

In order to find out the effects of shading and nitrogen fertilization on the accumulation of $NO_3\;^-$ in leaves of lettuce, lettuce plants were cultivated in the pots under glasshouse condition with different rates of shading(0, 50%) and nitrogen fertilization(100, 180, 200, 300, $400\;kg{\cdot}ha^{-1}$). The pH value was lower in soil after experiment than before experiment, whereas, contents of EC and $NO_3-N$ were higher. As the amounts of nitrogen fertilization were increased, pHs were decreased, but EC and the contents of $NO_3-N$ were increased. At the nitrogen fertilizations of 100, 180, 200, 300 and $400\;kg{\cdot}ha^{-1}$, the germination rates of lettuce were decreased to 84, 78, 76, 72 and 74%, and survival rates were also decreased to 94, 94, 90, 60 and 46%, respectively. However, the fresh weight of lettuce was highest at $45\;g{\cdot}plant^{-1}$ in the recommended fertilizer $plot(180\;kg{\cdot}ha^{-1})$ with non-shading condition. The contents of $NO_3\;^-$ in the leaves of lettuce were increased 2.8-4.1 times under 50% shading conditions than that under non-shading condition. It kept increasing up to seven order of growth phase; however, it started to decrease after eight order phase. Nitrate reductase activity of lettuce in non-shading condition was higher than that in 50% shading condition.

• Ecology and Resilient Infrastructure
• /
• v.3 no.1
• /
• pp.22-34
• /
• 2016

We developed a biologically-derived substance naphthoquinone (NQ) derivate for the eco-safe mitigation of harmful cyanobacteria blooms such as Microcystis and Dolichospermum. NQ was reacted with various substituents ($R_n$) to produce different NQ derivatives. We tested a total of 92 algicidal compounds based on the algicidal activity of Microcystis and Dolichospermum. 22 compounds of NQ were selected as candidates (algicidal activity >80% at $1{\mu}M$). Among them, NQ 40 compound showed the highest algicidal activity of 99.6% and 100% at the optimal concentration of $1{\mu}M$ on Microcystis and Dolichospermum, respectively. No algicidal effects of NQ 40 ($1{\mu}M$) were observed against non-target algae such as Stephanodiscus, Cyclotella and Peridinium. According to the results of acute eco-toxicity assessment, the $EC_{50}$ values of NQ 40 compound for Selenastrum capricornutum and Daphnia magna were 3.2 and $14.5{\mu}M$, respectively, and the $LC_{50}$ for Danio rerio was $15.7{\mu}M$. In addition, for D. magna chronic eco-toxicity assessment, no toxicity toward survival, growth and reproduction was observed. Therefore, we suggested the NQ 40 ($1{\mu}M$) compound as an alternative eco-safe algicidal substance to effectively mitigate harmful cyanobacteria blooms.

• Korean Journal of Clinical Laboratory Science
• /
• v.47 no.4
• /
• pp.298-305
• /
• 2015

Stem cell-like tumor cells are reported to be the main reason for tumor recurrence and metastasis. As one of the new approaches to overcome cancer, studies are emerging to inhibit the expressions of stem cell transcriptional factors (Oct4, Sox2, Klf-4, and Lin28) in cancer cells. MicroRNAs are master genetic regulators that can control development and differentiation of stem cells. In this study using various ovarian tumors (Skov3, Ovcar3, Tov112D, Tov21G, PA-1 and Hsc832(c)T), we examined the expressions of stem cell-related transcription factors, and the biological changes in cell survival and growth by miR-126 that targets stem cell transcriptional factors. We observed that treatment of miR-126 induced the morphological changes and cell suspension in most cells. In addition, miR-126 induced gradual regression of cell division except Skov3 cells, especially significant time-dependent reduction in Tov112D, Tov21G and PA-1. When we examined the expression of stem cell transcriptional factors, Sox2 was shown to be down-regulated after miR-126. Our results demonstrate that miR-126 treatment can provide the reversible environment to regulate cell division and to induce cell death of ovarian tumors, suggesting the molecular biological clues for clinical usage.

• Journal of Global Scholars of Marketing Science
• /
• v.8
• /
• pp.341-373
• /
• 2001

Firms are confronting the age of an infinite competition. In order to respond to the rapidly changing business environment and make a success and survival in the international and domestic securities market, firms must take a consideration on the stockholders value-oriented philosophy which has greatly contributed not only to the maximization of corporate profits but also to the stability of financial markets. To pursue stockholders value-oriented philosophy, a firm should build strong relationship with investors by providing exact information of firm's state, financial statement, management policy. Stockholders value-oriented philosophy contributes to long-term growth and development of the firm as well as efficient equity financing and friendship with stockholder. IR is the key factor to attain successful implementation of company's objective. It should be equipped with the most suitable organization and qualified man-power for IR activities. The purpose of this study was to examine the relationship between IR and relationship marketing management. Strategic implications of this study are as follows: First, This study provides a new explanations of IR activities in Relationship Marketing Management. Second, IR activities were key determinants of Trust and Commitment. That means the more a firm does IR activities, the more Trust and Commitment a firm has for their investors. Third, The variables of trust and commitment are highly related to marketing and financial success. IR have a positive effect on a company total value and its cost of capital relative to that of the overall market.

• The Journal of the Korea Contents Association
• /
• v.14 no.11
• /
• pp.695-701
• /
• 2014

The Police force and other public sector organizations do not like non-ethical evaluation of their members and disclosure of evaluation results. However, it is essential for survival and growth of the organization to identify, measure and resolve accurately the non-ethical behaviors of their members. In this study, the dimensions of police officers' unethical behavior were categorized as negligence, personal use, dishonesty, and misconduct of police officers, and the level of those dimensions were measured. After that, the differences due to the individual and work environmental characteristics were explored. The result showed that the level of non-ethical behavior was lowerer than the average. And the differences was statistically significant according to gender, rank of organization, deployed department of the work, and the period of work duration. This implied the necessities of education of police ethics, ethical atmosphere, and establishment of ethical system per differences in individual and work environmental characteristics. Also, considering the fact that the low level of ethical behavior did not lead to ethical action in actual and the inherent problem in research method how frankly the respondents answered the negative self-evaluation, continuous interest in non-ethical behavior and further systemic research are needed in a dimension of personnel management.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.16
• /
• pp.6649-6655
• /
• 2014

Radiation therapy is an important treatment for head and neck squamous cell carcinoma (HNSCC). However, how to promote radiation sensitivity in HNSCC remains a challenge. This study aimed to investigate the radiosensitizing effects of fenofibrate on HNSCC and explore the underlying mechanisms. HNSCC cell lines CNE-2 and KB were subjected to ionizing radiation (IR), in the presence or absence of fenofibrate treatment. Cell growth and survival, apoptosis and cell cycle were evaluated. In addition, CNE-2 cells were xenografted into nude mice and subjected to IR and/or fenofibrate treatment. The expression of cyclinB and CDK1 was detected by Western blotting. Our results showed that fenofibrate efficiently radiosensitized HNSCC cells and xenografts in mice, and induced apoptosis and G2/M arrest via reducing the activity of the CDK1/cyclinB1 kinase complex. These data suggest that fenofibrate could be a promising radiosensitizer for HNSCC radiotherapy.

• Information Systems Review
• /
• v.11 no.2
• /
• pp.45-66
• /
• 2009

A number of companies are considering for merger and acquisition (M&A) as one of business strategies for their growth and survival. However, many of them do not create the synergy they had sought, and failed M&A, often result in negative outcomes in terms of productivity, market share, profitability and turnover of qualified employees. There have been numerous research studies conducted to analyze the factors that determine the success and failure of M&A, and it has been found that with the increasing dependence of many companies on information systems, post-M&A IS (information systems) integration success has a critical effect on the success of M&A. However, there have been very few studies on post-M&A IS integration success, and most have been restricted to integration of IS organizations or physical information systems. In order to conduct a comprehensive research on the factors that affect the success of post-M&A IS integration, this study surveyed preceding researches on not only information systems but also strategic management, economics, finance, HRM (human resource management) and organization management. Based on the findings, a comprehensive and integrated model of the influential factors on post-M&A IS integration has been proposed. The proposed model categorizes the factors into perspectives of M&A, strategy, organization, HRM and IS, and provides an empirical evaluation of each factor on the success of IS integration based on comparative case studies.

• Korean Journal of Food Science and Technology
• /
• v.31 no.5
• /
• pp.1247-1253
• /
• 1999

Yakju(rice wine) was sterilized with high-voltage pulses of short time on a batch pulsed electric field(PEF) system. The initial microbial counts of Yakju were 7.52 X $10^4\;CFU/mL$ for total aerobes, 2.20 X $10^4\;CFU/mL$ for lactic acid bacteria and 7.08 X $10^4\;CFU/mL$ for yeasts. The pH, acidity and electric conductivity of Yakju were 3.36, 0.462% and 1.24 mS/cm, respectively. Yakju was treated with 2-250 of pulses exponential-wave formed electric pulses under the field strength of 12.5-25 kV/cm. The critical strengths of the electrical field for the sterilization of Yakju were 7.5 kV/cm for total aerobes, 8.5 kV/cm for lactic acid bacteria and 6.5 kV/cm for yeasts. Logarithmic survival rates decreased linearly at low pulse number, but curvilinearly at high pulse number. The PEF sterilization kinetics of Yakju could be analysed by In s = In A-k In (n) and the sterilization rate constant increased with electric field strength and the size of target microorganisms. No changed in pH, acidity, and the growth of microorganisms were found in the PEF treated Yakju during the storage for 6 weeks at both $4^{\circ}C$ And $30^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.5
• /
• pp.669-673
• /
• 1999

The effect of delayed initial feeding (1, 3, 5, 7 days) and starvation on morphological change, mortality and cannibalism on larvae of Siniperca scherzeri was examined by laboratory rearing. The larvae of S. scherzeri began to feed on Artemia nauplii at 4 days after hatching. In case of unfed and 7-days delayed groups, all of the larvae died at 12 days after hatching. The larvae of 1 day delayed feeding survived and grew as almost same as the control group, and 3-days delayed groups showed $33\%$ survival rate at the end of experiment (12 days after hatching). In case of the unfed group, total length of the starved larvae showed lower growth rate than the control group, and they did not reached at the same size of the larvae of the control group. Cannibalism were more common in the unfed group and the delayed fed group than the control group. The highest rate of daily mortality caused by cannibalism in the delayed fed group was $23\%$ at 8 days after hatching.