• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.2
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• pp.137-145
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• 1990

In this research, biological uptake of heavy metals(Cd(II), Cu(II), Zn(II)) was measured under various conditions ; pH, initial heavy metal concentration, temperature, contact time and the amount of biomass through batch test. From this research, it was found that heavy metals might be removed through adsorption and accumulation in activated sludge process. Heavy metals were highly concentrated by microbial floc in activated sludge. Also, the removal efficiency was reached up to 80~90% within and after 1 hour the increase of removal efficiency was minimal. The order of accumulation efficiency was Cu(II)>Zn(II)>Cd(II), and the bonding strength between heavy metals and microbial floc may be expressed in order of Cu(II)>Zn(II)>Cd(II).

• Journal of Plant Biology
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• v.22 no.1_2
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• pp.15-20
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• 1979

The present study was carried out to investigate the effects of cadmium(Cd), mercury(Hg) and lead(Pb) on the respiration of the germinating seeds. Two kinds of seeds namely, mungbean (Paseolus radiatus L.) and buckwheat (Fagopyrum esculentum M ench) were used for the plant materials. The concentrations of Cd, Hg, and Pb applied for the treatment were 0.1, 1, 10, 100 and 1,000ppm. The germination test was carried out in the dark at 27$^{\circ}C$. Regardless of the kinds of heavy metals, the respiration of the germinating seeds was greatly increased for 24hrs absorbing the heavy metals, and subsequently the respiration was increased average 0.69mg/g.hr.CO2 for mungbean and 0.7mg/g.hr.CO2 for buckwheat. In the lower concentrations of cadmium and lead than 10ppm the germinating rates, seedling concentraitons. The germinating rates, the seedling growth and the respiration were not increased in ay concentrations of mercury, but were decreased with increase of the mercury concenration. The inhibition of seeds respiration by mercury was 3 times higher than by cadmium, and 5 times higher than that by lead. The toxicity of three heavy metals on the respiration was showed from the highest to the lowest in the order of Hg, Cd, and Pb.

• Environmental Analysis Health and Toxicology
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• v.18 no.4
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• pp.295-303
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• 2003

Physiological cellular activities responses to cadmium (Cd) exposure in green algae with several reductases activities and viability of the cell were examined. The cell division of green algae, Selenastrum capricornutum treated with 5ppm was significantly decreased than that of normal algae. The mean cell number of normal algal culture was as twice much as than that of algae at 6 days after Cd treatment. The cellular viability of algae was analysed by flow-cytometry with fluorescent dye after esterase reaction on cell membrane. The 85.35% of cellular viability of normal culture was decreased to 34.35% when algae was treated with 5 ppm of Cd at 6 days after treatment. It was considered that those method of flow-cytometry is useful tool for toxicity test on micro-organisms in the respect of identifying cellular viability. Also, the activities of both glutathione peroxidase (GPX) and ascorbate peroxidase (APX), which are indirectly react against oxidative stress through reduction of glutathione by Cd were significantly increased with 25%. It is considered that both GPX and APX are involved in the metabolic pathway of Cd -detoxification with similar portion in Selenasturm capricornutum.

• Journal of Korea Foundry Society
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• v.25 no.6
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• pp.233-239
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• 2005

Contact material is widely used in the field of electrical parts. Ag-CdO has a good wear resistance and stable contact resistance. We studied a lifetime of Ag-CdO material because of getting better properties of Ag-CdO using Post-oxidation. The experimental procedure were melting using high frequency induction, heat treatment, rolling and internal oxidation. And we experimented on difference process, Post-oxidaion. Then we tested a lifetime and analysed. We obtained the optimizing oxidation temperature was $750^{\circ}C$. Using Pre-oxidation, coarse oxide and depleted oxidation layer existed but finer oxides were existed and depleted oxidation layer was not using Post-oxidation. In Post-oxidation, The density was 10 $g/cm^{3}$, the hardness was Hv 80 and the adhesive strength was 9000N. The specimen of Post-oxidation had better lifetime properties than that of Pre-oxidation. We predicted that the lifetime of Post-oxidation specimen is more longer twice than that of Pre-oxidation one.

• Journal of fish pathology
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• v.14 no.2
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• pp.97-102
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• 2001

Olive flounder, Paralichthys olivaceus known as an one of the major aquacultured species in Korea were exposed to cadmium(Cd) with different protocols and analyzed the effects of exposure on the immune response. Antibody levels in sera of the group exposed to Cd(20ppb) by immersion method from 2 weeks before immuniztion with formalinised Edwardsiella tarda(E. tarda) KFE entigen to the end of experiment reached to peak level faster than that of the non-exposed group. After this peaking time the levels decreased much at a faster rate compared to the non-exposed group. This tendency was also appeared in the numbers of specific antibody secreting cells(SASC) analyzed with the enzyme-linked immunospot (ELISPOT)-assay technique in the splenocytes of the experimental groups exposed to Cd with different ways. Interestingly, the group exposed to Cd for 2 weeks before immunization also showed increased numbers of SASC unlikely the antibody production and suggested a more critical influence of cadmium exposure in early stage of immune reaction. Artificial infection with live E. tarda KFE induces 100% mortality in the flounder exposed to cadmium throughout the experimental period from two weeks before the immunization. It may imply that some other factors related to specific immunity are involving in the defence system of flounder exposed to Cd. Taked together. Cd exposure may induce temporaily stimulatory or indhibitory effects on the immune reaction, but suppress the physiological systems for the resistant against the infective agents with other toxic effects.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.471-477
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• 2000

Background : Coughing is the most common complaint for which patients seek medical service. When caughing continues over 3 weeks in non-smokers who do not take cough-provoking drugs, they are classified as patients with chronic cough. Three well known main causes of chronic caugh are postnasal drip syndrome, bronchial asthma and gastroesophaseal reflux disease. Among them, postnasal drip syndrome is reported to be the most common cause of all in chronic cough diseases, and allergic inflammation plays an important role in the pathogenesis of postnasal drip syndrome. CD23 and CD25 which are low affinity receptor for IgE and IL-2 receptor alpha, respectively, are closely related to allergic inflammation and their roles were evaluated in chronic cough patients. Methods : We evaluated 105 patients with chronic cough and selected 56 patients for measurement of serum CD23 & CD25 levels. We selected 10 normal, medical students for comparison of serum CD23 & CD25 levels. Result : The postnasal drip syndrome was found to be the most common cause of chronic cough. Serum CD23 and CD25 did not increase in chronic cough patient compared to normal controls. However in bronchial asthma patient, serum CD23 level was increased relative to normal control (p<0.05). Conclusion : In bronchial asthma presented as chronic cough, lymphocyte mediated allergic inflammation may related with the pathogenesis of the disease.

• Environmental Analysis Health and Toxicology
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• v.25 no.1
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• pp.19-26
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• 2010

Discharged materials from the point or non-point source are released into the sea, and as the results, marine environment is directly affected. We must estimate the impacts of contaminants to marine pollution rapidly and accurately. Therefore, it is needed on early warning system for appreciating marine environmental impacts, and required a bioassay to evaluate abnormal changes. A bioassay test was developed to examine the effects of heavy metal contaminants on the early life stages of the marine annimals. We have studied the effects of metals on early development of a sea urchin species, Strongylocentrotus intermedius. S. intermedius embryos were tested with six metals (Cu, Ag, Zn, Cd, Cr, Ni) and showed the highest sensitivity to Cu as well as the lowest sensitivity to Cd. The order of biological impact for metals was Cu>Ag>Ni>Zn>Cr>Cd. In accordance with the results, sea urchins embryos can provide biological criteria for seawater quality assessment. The sensitivity of developmental bioassay whith S. intermedius is at intermediate level among marine organisms commonly used in aquatic bioassays. And this sea urchin can be routinely employed as a test organism for ecotoxicity assays.

• Geomechanics and Engineering
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• v.1 no.1
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• pp.35-52
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• 2009

A significantly thick zone of steep slopes is commonly encountered above groundwater table and the soils within this zone are unsaturated with negative pore-water pressures (i.e., matric suction). Matric suction contributes significantly to the shear strength of soil and to the factor of safety of unsaturated slopes. However, infiltration during rainfall increases the pore-water pressure in soil resulting in a decrease in the matric suction and the shear strength of the soil. As a result, rainfall infiltration may eventually trigger a slope failure. Therefore, understanding of shear strength characteristics of saturated and unsaturated soils under shearing-infiltration (SI) conditions have direct implications in assessment of slope stability under rainfall conditions. This paper presents results from a series of consolidated drained (CD) and shearing-infiltration (SI) tests. Results show that the failure envelope obtained from the shearing-infiltration tests is independent of the infiltration rate. Failure envelopes obtained from CD and SI tests appear to be similar. For practical purposes the shear strength parameters from the CD tests can be used in stability analyses of slopes under rainfall conditions. The SI tests might be performed to obtain more conservative shear strength parameters and to study the pore-water pressure changes during infiltration.

• Journal of Medicine and Life Science
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• v.18 no.1
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• pp.16-19
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• 2021

Cushing's disease (CD) is a rare illness characterized by chronic hypercortisolism secondary to the overproduction of adrenocorticotropic hormone by a pituitary adenoma, which is associated with a high risk of developing serious complications, such as diabetes mellitus, cardiovascular disease, and emotional disorders. Endoscopic transsphenoidal surgery is performed for the treatment of CD, and was initially preferred over other types of treatments. However, the recurrence after pituitary surgery for CD is a common problem after an initial successful surgery. In microadenomas, the remission rates were higher than those of macroadenoma. This patient had a giant tumor that was greater than 4 cm in length on sella magnetic resonance imaging, and panhypopituitarism was detected using a combined pituitary stimulation test. After transsphenoidal surgery, the patient required temporary hormone replacement for a short period of time. After 1 year, he showed a normal cortisol response on the overnight dexamethasone suppression test and low morning cortisol levels. Therefore, we indicated that the patient was cured of giant macroadenoma with panhypopituitarism before surgery, and thus, reported this case.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.202-210
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• 2005

In this study, the fly ash was employed as a possible alternative to the bentonite for its high sorption capacity against cationic heavy metal. To consider the constituents of barrier possibly used, the specimens were mixed with different material contents (fly ash : weathered soil : bentonite), then sorption test was performed. Also the specimens were molded on the wet side of optimum moisture contents like mixing ratio of sorption test and their hydraulic conductivities were measured in flexible-wall permeameters. And to confirm the effect of dissolved cations, the hydraulic conductivity tests were repeated by converting the permeant liquids from water to $Cd^{2+}$ solution. Finally, the Cd-concentration at the effluent was analyzed for 500hrs to compare the effectiveness of each specimen in contaminant retardation. Test results showed that the more the ratio of fly ash increase, the more Kd value increase, and the hydraulic conductivity of weathered soil/bentonite (95:5) mixture was the lowest $(2.9*10^{-8}cm/sec)$, and specimens made of fly ash and fly ash/weathered soil mixtures showed similar hydraulic conductivity. Although the permeant liquid was changed from water to $Cd^{2+}$ solution, the hydraulic conductivity of all specimens except for weathered soil maintained similarly like before. Consequently, the initial breakthrough point of Cd in weathered soil specimen was observed at about 5hrs after the test started while that of fly ash specimens was not observed during the whole test period of 500hrs. The results implied that fly ash had a sufficient retardation capacity against contaminant transport possibly by its high sorption capacity although it showed little effect on the reduction of hydraulic conductivity. Based on the test results, it could be concluded that the fly ash can be possibly used as a suitable barrier material in containment system to attenuate the contaminant transport for its high retardation capacity and for the low cost.