• 한국작물학회지
• /
• 제51권2호
• /
• pp.118-122
• /
• 2006

This experiment was carried out on plastic pots ($40cm{\times}25cm{\times}30cm$) filled with sand soil at greenhouse using two soybean cultivars with small seed; one was Pungsannamulkong (PSNK) recognized as a tolerant cultivar against excessive water stress and the other one was Sobaeknamulkong (SBNK) recognized as a susceptible cultivar. Seed was sown with 30 plants of 2 hills, and the amount of applied fertilizer was N; 3.0 g, P; 3.0 g, and K; 3.4 g per $m^2$ with all basal fertilizations. Plants were grown under photoperiod of natural light with day temperature of $31{\pm}5^{\circ}C$ and night temperature of $22{\pm}1^{\circ}C$. The flooding treatment was done for 3, 5, 7 and 10 days by filling pots with tap water up to 1 cm above the level of the soil surface when plants were 2 days after emerging. Nitrogen uptake by leaves of soybeans decreased significantly by the flooding after 6 days. This significant reduction of N uptake by flooding was evidently recognized from the chlorosis of leaves. The dry matter of flooded soybean seedlings significantly decreased compared to non-flooded soybean seedlings at 10 days. The dry matter of roots also showed similar result of the shoot. Shoots had more N reduction than roots under the flooding. This N reduction was more pronounce in SBNK than in PSNK. Chlorophyll content of flooded soybeans showed decreasing or non-increasing tendency, and the reduction of chlorophyll content was more in SBNK than in PSNK from the flooding stress. Nitrate content of soybean seedlings with flooding stress showed decreasing tendency in shoot and root parts. Ammonium content, however, was higher in flooding stress compared to the non-flooding. Flooding caused a remarkable change in the AA (amino acid) composition and TAA (total amino acid) concentration in the leaves of soybean seedlings.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
• /
• pp.366-372
• /
• 1999

The deformation behavior of commercial stainless steels under hot rolling conditions was investigated by means of hot compression tests performed in the temperature range 800$^{\circ}C$ to 1200$^{\circ}C$. The measured flow stress-strain curves were analyzed by using a simple flow stress model. It was found that the reference strength of stainless steels are much higher than that of carbon steel and that nitrogen and molybdenum alloying greatly increases flow stress of austenitic stainless steel. Ferritic and duplex stainless steel showed comparatively low flow stresses. The flow stress model, which correlates the flow stress with temperature and strain rate, was applied to predict roll forces during hot-plate rolling of stainless steels.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
• /
• pp.72-73
• /
• 2005

Stress behavior was studied to investigate the internal behaviors of boron, carbon, and nitrogen in the 1000${\AA}$-thick tungsten boron carbon nitride (W-B-C-N) thin films. The impurities in the W-B-C-N thin films provide stuffing effects that were very effective for preventing the interdiffusion between interconnection metal and silicon substrate during the subsequent high temperature annealing process. The resistivity of W-B-C-N thin film decreases as an annealing temperature increase. The W-B-C-N thin films have compressive stress, and the stress value decreased up to $4.11\times10^{10}dyne/cm^2$ as an $N_2$ flow rate increases up to 3 sccm.

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2002년도 Current Trends in Toxicological Sciences
• /
• pp.94-94
• /
• 2002

Oxidative stress induced by reactive oxygen and/or nitrogen species has been considered as a major cause of cellular injuries in a variety of neurodegenerative disorders including Alzheimer's disease (AD). Inflammatory as well as oxidative tissue damage has been implicated in pathophysiology of AD, and non-steroidal anti-inflammatory drugs have been reported to have beneficial effects in the treatment or prevention of AD.(omitted)

• 농업과학연구
• /
• 제46권3호
• /
• pp.637-643
• /
• 2019

The aim of the present study was to evaluate the effect of the induced heat stress on physiological response and serum biochemical parameters involving glucose, cholesterol, blood urea nitrogen (BUN), non-esterified fatty acids (NEFA), and cortisol in Holstein calves. Ten calves were kept in a climate controlled room (air temperature $37^{\circ}C$ and 90% humidity from 09:00 to 19:00) for three days. Those animals were given a one-day adaptation period. During the treatment period, we measured the skin temperature six times. Following the treatment periods, blood samples were collected before the experiment began (09:00) and at the end of the stress period (19:00). To aid analysis of the biochemical parameters, also we monitored the rectal temperature. The results, exhibited that both rectal and skin temperature showed increase in the heat stress-induced animals as compared with unstressed animals. Moreover, we noticed that the levels of BUN and NEFA increased in the blood serum of heat stress induced animals when compared with un-stressed ones. From these results, we concluded that the physiological and biochemical changes in the calves were induced by heat stress. Hence, the present study findings could be employed as base line data for development of stress reduction techniques in the dairy industry.

• The Korean Journal of Ecology
• /
• 제15권4호
• /
• pp.377-386
• /
• 1992

Seasonal changes of symbiotic nitrogen-fixation activity and growth characteristics of four different natural populations of kummerowia striata were quantitatively analyzed during the growing period. the nitrogen-fixation activity of root nodules attained the maximum rates of 148, 132, 102 and 100$\muM\;C_2H_4\;\cdot\;g\;fw\;nodule^{-1}\;\cdot\;hr^{-1}$, respectively for sunny, multibranched, shade and unibranched populations at the optimum growth conditions. and the seasonal changes showed fluctuations by environmental conditions such as light, temperature, nutrient contents, water stress and plant ages, etc. The multibranched plant showed the greater amount of leaf and root nodule biomass, and the higher nitrogenase activity than the unibranched plant. the optimum conditions of leaf chloropht11 and water content of each organ indicated the active growth and the maximum fresh biomass of 4 different populations were 1.92, 1.85, 0.97 and 0.56 g $fw\cdotplant^{-1}$ for shade multibranched, sunny and unibranched populations, respectively.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
• /
• pp.542-543
• /
• 2005

In this paper, describes the fabrication and dielectric insulation characteristics experimental results of the model cable for the 22.9kV class HTS power cable. The model cable were tested with partial discharge(PD), AC and impulse withstand voltage in liquid nitrogen($LN_2$) and liquid nitrogen pressure. In these test results, PD inception stress and AC, impulse breakdown strength increase as the pressure of the liquid nitrogen increases.

• Journal of Applied Biological Chemistry
• /
• 제51권6호
• /
• pp.262-271
• /
• 2008

Natural abundances of stable isotopes of nitrogen and carbon (${\delta}^{15}N$ and ${\delta}^{13}C$) are being widely used to study N and C cycle processes in plant and soil systems. Variations in ${\delta}^{15}N$ of the soil and the plant reflect the potentially variable isotope signature of the external N sources and the isotope fractionation during the N cycle process. $N_2$ fixation and N fertilizer supply the nitrogen, whose ${\delta}^{15}N$ is close to 0%o, whereas the compost as. an organic input generally provides the nitrogen enriched in $^{15}N$ compared to the atmospheric $N_2$. The isotope fractionation during the N cycle process decreases the ${\delta}^{15}N$ of the substrate and increases the ${\delta}^{15}N$ of the product. N transformations such as N mineralization, nitrification, denitrification, assimilation, and the $NH_3$ volatilization have a specific isotope fractionation factor (${\alpha}$) for each N process. Variation in the ${\delta}^{13}C$ of plants reflects the photosynthetic type of plant, which affects the isotope fractionation during photosynthesis. The ${\delta}^{13}C$ of C3 plant is significantly lower than, whereas the ${\delta}^{13}C$ of C4 plant is similar to that of the atmospheric $CO_2$. Variation in the isotope fractionation of carbon and nitrogen can be observed under different environmental conditions. The effect of environmental factors on the stomatal conductance and the carboxylation rate affects the carbon isotope fractionation during photosynthesis. Changes in the environmental factors such as temperature and salt concentration affect the nitrogen isotope fractionation during the N cycle processes; however, the mechanism of variation in the nitrogen isotope fractionation has not been studied as much as that in the carbon isotope fractionation. Isotope fractionation factors of carbon and nitrogen could be the integrated factors for interpreting the effects of the environmental factors on plants and soils.

• BMB Reports
• /
• 제35권1호
• /
• pp.67-86
• /
• 2002

Three routes have been identified triggering neuronal death under physiological and pathological conditions. Excess activation of ionotropic glutamate receptors cause influx and accumulation of $Ca^{2+}$ and $Na^+$ that result in rapid swelling and subsequent neuronal death within a few hours. The second route is caused by oxidative stress due to accumulation of reactive oxygen and nitrogen species. Apoptosis or programmed cell death that often occurs during developmental process has been coined as additional route to pathological neuronal death in the mature nervous system. Evidence is being accumulated that excitotoxicity, oxidative stress, and apoptosis propagate through distinctive and mutually exclusive signal transduction pathway and contribute to neuronal loss following hypoxic-ischemic brain injury. Thus, the therapeutic intervention of hypoxic-ischemic neuronal injury should be aimed to prevent excitotoxicity, oxidative stress, and apoptosis in a concerted way.

• Journal of Crop Science and Biotechnology
• /
• 제11권2호
• /
• pp.111-118
• /
• 2008

Soybean is sensitive to waterlogging stress, leading to reduce their growth and yield significantly. The objective of this study was to characterize the relative sensitivities of biomass accumulation and specific nodule activity under waterlogging stress between supernoduating mutants, 'SS2-2' and 'Sakukei 4' and their wild-type soybeans, 'Sinpaldalkong 2' and 'Enrei', respectively. Flooding treatment was performed to soybean plants grown in a pot by waterlogging for 15 days from the beginning bloom(R1) stage under natural light. The nodule number and weight were considerably decreased by waterlogging stress. The bleeding sap rate of waterlogging soybean plants was decreased by 78-80% in supernodulating mutants and 65-74% in their wild types compared to control plants. The relative ureide-N content was also decreased by waterlogging and the reduction was high in supernodulating mutants. This may cause the massive reduction of shoot and root dry weight and leaf area in waterlogged soybean plants. There was a varietal difference in response to the waterlogging stress. During the waterlogging, supernodulating mutants maintained higher spad value than their wild types. Particularly, the difference between soybean varieties was clear in low rank leaves from the top. Also, supernodulating mutants showed a weak waterlogging tolerance than their wild types. Under waterlogging conditions, massive nodules were considerably destroyed and specific nodule activity after waterlogging may not be recovered when compared to their wild-type soybeans. Supernodulating mutants showed lower seed yield than their wild types in waterlogging conditions.