• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.05a
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• pp.8-11
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• 1997

Current methods of evaluating soil contamination by heavy metals rely on analyzing samples for total contents of metals or quantities recovered in various chemical extracting solutions. Results from these approaches provide only an index for evaluation because these methodologies yield values not directly related to bioavailability of soil-borne metals. In addition, even though concentrations of metals may be less than those required to cause toxic effects to biota, they may cause substantial effects on soil chemical parameters that determine soil quality and sustainable productivity. The objective of this research was to characterize effects of Cu or Cd additions on soil solution chemistry of soil quality indices, such as pH, EC, nutrient cation distribution and quantity/intensity relations (buffer capacity). Metals were added at rates ranging from 0 to 400 mg/kg of soil. Soil solution was sequentially extracted from saturated pastes using vacuum. Concentrations of Cu or Cd remaining in soil solutions were very low as compared to those added to the soils, warranting that most of the added metals were recovered as nonavailable (strongly adsorbed) fractions. Adsorption of the added metals released cations into soil solution causing increases of soluble cation contents and thus ionic strength of soil solution. At metal additions of 200~400 mg/kg, EC of soil solution increased to as much as 2~4 dS/m; salinity levels considered high enough to cause detrimental effects on plant production. More divalent cations (Ca+Mg) than monovalent cations (K+Na) were exchanged by Cu or Cd adsorption. The loss of exchangeable nutrient cations decreased long-term nutrient supplying capacity or each soil. At 100 mg/kg or metal loading, the buffering capacity was decreased by 60%. pH of soil solution decreased linearly with increasing metal loading rates, with a decrement of up to 1.3 units at 400 mg Cu/kg addition. Influences of Cu on each of these soil quality parameters were consistently greater than those of Cd. These effects were of a detrimental nature and large enough in most cases to significantly impact soil productivity. It is clear that new protocols are needed for evaluating potential effects of heavy metal loading of soils.

• The Journal of Advanced Prosthodontics
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• v.7 no.1
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• pp.21-26
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• 2015

PURPOSE. To evaluate the cytotoxicity of temporary luting cements on bovine dental pulp-derived cells (bDPCs). MATERIALS AND METHODS. Four different temporary cements were tested: Rely X Temp E (3M ESPE), Ultratemp (Ultradent), GC Fuji Temp (GC), and Rely X Temp NE (3M ESPE). The materials were prepared as discs and incubated in Dulbecco's modified eagle's culture medium (DMEM) for 72 hours according to ISO 10993-5. A real-time cell analyzer was used to determine cell vitality. After seeding $200{\mu}L$ of the cell suspensions into the wells of a 96-well plate, the bDPCs were cured with bioactive components released by the test materials and observed every 15 minutes for 98 hours. One-way ANOVA and Tukey-Kramer tests were used to analyze the results of the proliferation experiments. RESULTS. All tested temporary cements showed significant decreases in the bDPCs index. Rely X Temp E, GC Fuji Temp, and Rely X Temp NE were severely toxic at both time points (24 and 72 hours) (P<.001). When the cells were exposed to media by Ultratemp, the cell viability was similar to that of the control at 24 hours (P>.05); however, the cell viability was significantly reduced at 72 hours (P<.001). Light and scanning electron microscopy examination confirmed these results. CONCLUSION. The cytotoxic effects of temporary cements on pulpal tissue should be evaluated when choosing cement for luting provisional restorations.

• The Journal of Korean Medicine
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• v.35 no.1
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• pp.114-123
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• 2014

Objectives: Evidence-based medicine(EBM) advocates the use of up-to-date "best" scientific evidence from health care research as the basis for making medical decisions. EBM also has been applied to traditional Korean medicine(TKM), especially in the field of safety. Recently, the standard prescription for TKM by Korea Institute of Oriental Medicine was published based on toxic index from various toxicity tests. However, there are some limitations when the results from the study based on EBM are applied in clinics. To overcome these imitations, the term "evidence-based practical medicine" was developed and defined as clinically applicable results from the study based on EBM. And safety classification for TKM was suggested as an example of evidence-based practical medicine. Methods: For safety classification for TKM, the data for $LD_{50}$(50% lethal dose), which was transformed to theoretical $LD_1$(1% lethal dose), was analyzed as one of tools for EMB study and divided by maximum dose used in clinics. Results and Conclusions: As a result, human equivalent dose(HED)-based MOS(margin of safety) for korean traditional medicine was calculated and used for safety classification with 5 categories. These categories would be helpful for oriental medicine clinicians to decide the increase and decrease of dosage according to various factors such as patient's sensitivity, potential toxicity of herbal medicines, clinician's experience for better cure. Thus, this safety classification provides some evidences enough that evidence-based practical medicine should be not the same with EBM and defined differently from EBM.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.3
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• pp.11-18
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• 1991

Volatile organic compounds(VOC) present in or generated by many sources, can be toxic, mutagenic or even carcinogenic, so that control of such emissions is significant. The 6 chlorinated organic chemicals as VOC were examined in this study. Prediction of the behavior of VOC on activated carbon beds is an important part of control system design. The objective of this study was to predict gas phase sorption isotherms from physical properties and liquid phase isotherms obtained with the same adsorbent and adsorbate. One of the techniques that was investigated was quantitative structure-activity relationships(QSAR) for the predicition procedures. It was possible to estimate sorption isotherms in the gas phase($a_g$) using either connectivity index, $^2{\chi}$, and the Henry's law coefficient ($H_a$) or the solubility and the equilibrium concentration in the gas phase. As a result of study, the predictive equation based on Freundlich model for $a_g$ was ${\log}\;a_g=0.238\;^2{\chi}+0.573\;{\log}\;H_a+4.330(r^2=0.94)$. Finally, this would provide a potentially useful tool to describe and predict sorption capacity without time-consuming tests.

• Fisheries and Aquatic Sciences
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• v.19 no.10
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• pp.44.1-44.8
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• 2016

Rockfish, Sebastes schlegelii (mean length $14.53{\pm}1.14cm$ and mean weight $38.36{\pm}3.45g$), were exposed for 4 weeks with the different levels of ammonia in the concentrations of 0, 0.1, 0.5, and 1.0 mg/L at 19 and $24^{\circ}C$. The indicators of growth performance such as daily length gain, daily weight gain, condition factor, and hematosomatic index were significantly reduced by the ammonia exposure and high temperature. The ammonia exposure induced a significant decrease in hematological parameters, such as red blood cell (RBC) count, white blood cell (WBC) count, hemoglobin (Hb), and hematocrit (Ht), whose trend was more remarkable at $24^{\circ}C$. Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were also notably decreased by the ammonia exposure. Blood ammonia concentration was considerably increased by the ammonia concentration exposure. In the serum components, the glucose, glutamic oxalate transaminase (GOT), and glutamic pyruvate transaminase (GPT) were substantially increased by the ammonia exposure, whereas total protein was significantly decreased. But, the calcium and magnesium were not considerably changed.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.497-501
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• 2005

An experiment was conducted on crossbred male calves to study the effect of arsenic (As) on immunity status and certain hematological parameters. Ten crossbred male calves of 3-4 months of age were distributed into two equal groups. Group I was kept as control, whereas, group II was supplemented daily with 50 ppm As (as $As_sO_3$) up to 90 days, in the diet. Calves of both groups were fed as per ICAR standards and their requirements were fulfilled by feeding concentrate mixture and green oats. All calves were kept under similar managemental conditions. Blood samples were collected at fortnightly intervals to estimate various haematological parameters and superoxide dismutase (SOD) enzyme activity. Serum Ig and serum glutamic pyruvate transaminase (SGPT) were also measured. Cell-mediated immune responses of the calves were monitored at 0, 45 and 90 of experimental feeding, through lymphocyte proliferation. No change in blood total leukocyte counts (TLC), differential leukocyte counts (DLC), packed cell volume (PCV), haemoglobin (Hb) and SGPT was observed with As supplementation. A decrease in SOD activity was noticed in group II calves. Stimulation index (SI) for lymphocyte proliferation decreased from 1.14 to 0.79 in group II calves during 90 days experimental feeding, whereas, there was no change in SI values in group I indicating significant decrease in immune response of As supplemented calves. Blood As concentration increased in group II calves with the decrease in immune response. Short term supplementation of As to growing calves suggested suppressive effects on cell-mediated immunity. However, long term experiments are required to demonstrate clearly the efects of this toxic metal in calves.

• Fire Science and Engineering
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• v.14 no.4
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• pp.7-16
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• 2000

In the study, three criteria(toxicity, fire & explosion, environment) and damage prediction method for each case was set up, and all these criteria were applied to the subject substance that was selected as hazardous level by integrating all criteria through Algorithm. Particularly, the environment criterion is a comprehensive concept, environment index modeling by combining USCG(United State Coast Guard) & MSDS(Material Safety Data Sheet) environment criteria classifications and the environment part of MFPA's health hazardousnes(Nh). And for damage prediction method of each criterion were adopted and they were applied to hazardous chemical substances in use or stored by chemical substance related enterprises located in each region that made possible to set up total hazard level of used substances(inflammability, poisonousness and counteraction on a unit substance, and hazard level & display modeling on environment) & damage prediction in case of accident & solidity setup(CPQRA: Chemical Process Quantitative Risk Assessment, IAEA: International Atomic Energy Agency, VZ eq: Vulnerable Zone) risk counter. Thus it is deemed that it can be applied to toxic substance leakage that can happen during any chemical processing & storage, application as a tool for prior safety evaluation through potential dangerousness computation of fire & explosion.

• Journal of Radiation Protection and Research
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• v.14 no.1
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• pp.8-15
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• 1989

After administration of $^{99m}TC,\;^{67}Ga,\;^{131}I,\;^{32}P\;and\;^{238}U(UO_2(NO_2)_3{\cdot}6H_2O)$, in male rats, toxic effects were examined by determining the biological materials in blood. Dosages of radio-nuclides injected are based on the amounts routinely administered to patients, and concentrations of BUN, creatinine, SGOT, SGPT and $PGE_2$ in plasma are determinated as indices to the biochemical response. No increase of creatinine was observed after injection of $^{99m}TC$. Concentrations of BUN, SGOT and $PGE_2$ were not significantly increased in comparison with before-administration. Administration of $^{67}Ga,\;^{131}I\;and\;^{32}P$, did not significantly change BUN, SGPT and SGOT, but largely increased $PGE_2$ than control levels. Besides, $^{238}U$ Showed the most severe toxicity. From the above results, we suggest that the determination of $PGE_2$ in plasma can be used as an index in case of elvaluating the effects of radiation toxicity by nuclides used in nuclear medicine.

• Elastomers and Composites
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• v.51 no.2
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• pp.147-153
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• 2016

Polyvinyl chloride (PVC) has been used as a general-purpose polymer because of its lower cost, good durability and mechanical properties compared to other materials. However, PVC is vulnerable to heat deformation and generates a toxic gas like hydrogen chloride. Therefore, it is important to delay or prevent the flame retardancy and thermal degradation of the PVC during the processing. It was reported that aluminum trihydroxide (ATH) improved flame retardancy as well as smoke inhibition of the virgin polymer. In this study, PVC composites by addition of ATH were compounded in a modular intermeshing co-rotating twin screw extruder. The PVC composites with different concentrations of ATH (0~5 phr) were analyzed. Flame retardancy of the PVC composite significantly increased depending on the ATH concentration. LOI of the composite also increased with the concentration of ATH. There were no significant differences for the thermal properties of the PVC composites with ATH.

• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.11-19
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• 1992

To find out an effective way of treating the toxicity of cadmium, concentrations of $K^+,\;Ca^{2+}$ and c-AMP, and activities of GOT and GPT in blood of rats were determined at definite time intervals after administration of cadmium to rats. Cadmium caused more decrease of $Ca^{2+}$ concentration than $K^+$ concentration but increases of GOT and GPT activities and of c-AMP concentrations. The decreased concentration of $Ca^{2+}$ was not recovered by selenium or metallothionein. However, the increased activities of GOT and GPT, and the c-AMP concentration were down regulated remarkably by selenium but not by metallothionein. These results suggested that selenium might have the compensate effects concerning toxic index against cadmium such as increases of GOT and GPT activities, and of c-AMP concentration.