• Development and Reproduction
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• v.13 no.4
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• pp.321-327
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• 2009

This study aimed to examine the testis toxicities of metal compound, manganese (Mn), which may be generated as mist or fume in the industrial sites. As well as serum prolactin (PRL) concentration was analyzed because Mn accumulation in basal ganglia up-regulates serum PRL and hyperprolactinemia consecutively induces the testis toxicity. Male F344 rats were divided into the 4 groups (2 controls and 2 Mn treated groups, n=10) on the basis of the test condition (inhalation, Mn $1.5mg/m^3$ or not) and treatment period (for 4-weeks and 13-weeks). The treatment time was 6 hr. a day, 5 days a week for the whole body. Basic tests including changes in body weight, feed rate were observed. Blood and testis Mn concentration, and testis toxicity test such as the number and deformity test of sperm were also observed. Serum PRL level was analyzed by ELISA to certify the relationship between the Mn induced increase of the serum PRL level and sperm production. Blood and testis Mn concentrations were significantly and dose-dependently increased. Sperm count was decreased in Mn-treatment groups than control in a treatment time dependent manner. Morphological analysis of cauda epidydimal sperm showed that the frequencies of morphologically abnormal sperms such as bent tail and small head were increased in the both Mn-treatment groups than control. A significant increase in serum PRL levels was found in response to Mn treatment but it was not hyperprolactinemia range. These results suggest that treatment of Mn up-regulates the serum PRL concentration and induces the testis toxicity. The No Aversed Effect Level (NOAEL) of inhaled Mn on the male rat testis may be under the $1.5mg/m^3$.

• Journal of the Korean Vacuum Society
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• v.2 no.2
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• pp.188-198
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• 1993

We have developed a technique for growing thin oxides (6~10 nm) by the Last step TCA method. N-channel metal-oxide-semiconductor (n-MOS) capacitor and n-channel metal-oxide-semiconductor field-effect transistor's (MOSFET's) having a gate oxide with chlorine incorporated $SiO_2/Si$ interface have been analyzed by electrical measurements and physical methods, such as secondary ion mass spectrometry (SIMS) and electron spectroscopy for chemical analysis (ESCA). The gate oxide grown with the Last strp TCA method has good characteristics as follows: the electron mobility of the MOSFET's with the Last step TCA method was increased by about 7% and the defect density at the $SiO_2/Si$ interface decreases slightly compared with that with No TCA method. In reliability estimation, the breakdown field was 18 MV/cm, 0.6 MV/cm higher than that of the gate oxide with No TCA method, and the lifetime estimated by TDDB measurement was longer than 20 years. The device lifetime estimated from hot-carrier reliability was proven to be enhanced. As the results, the gate oxide having a $SiO_2/Si$ interface incorporated with chlorine has good characteristics. Our new technique of Last step TCA method may be used to improve the endurance and retention of MOSFET's and to alleviate the degradation of thin oxides in short-channel MOS devices.

• Journal of Life Science
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• v.26 no.12
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• pp.1367-1375
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• 2016

Cilostazol is known to be a selective inhibitor of phosphodiesterase III and is generally used to treat stroke. Our previous findings showed that cilostazol enhanced capillary density through angiogenesis after focal cerebral ischemia. Angiogenesis is an important physiological process for promoting revascularization to overcome tissue ischemia. It is a multistep process consisting of endothelial cell proliferation, migration, and tubular structure formation. Here, we examined the modulatory effect of cilostazol at each step of the angiogenic mechanism by using human brain microvascular endothelial cells (HBMECs). We found that cilostazol increased the migration of HBMECs in a dose-dependent manner. However, it did not enhance HBMEC proliferation and capillary-like tube formation. We used a cDNA microarray to analyze the mechanisms of cilostazol in cell migration. We picked five candidate genes that were potentially related to cell migration, and we confirmed the gene expression levels by real-time PCR. The genes phosphoserine aminotransferase 1 (PSAT1) and CCAAT/enhancer binding protein ${\beta}$ ($C/EBP{\beta}$) were up-regulated. The genes tissue factor pathway inhibitor 2 (TFPI2), retinoic acid receptor responder 1 (RARRES1), and RARRES3 were down-regulated. Our observations suggest that cilostazol can promote angiogenesis by promoting endothelial migration. Understanding the cilostazol-modulated regulatory mechanisms in brain endothelial cells may help stimulate blood vessel formation for the treatment of ischemic diseases.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.837-844
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• 2017

Generally, V/C ratio in uninterrupted traffic flow and average travel speed in interrupted traffic flow are utilized as measure of effect for assessing operational situation of roads. The set of road conditions and traffic conditions are considered to be major variables for assessing operational situation in the traffic flow. However, weather conditions such as rainfall also affect the operational situation of roads. The studies reflected by the rainy situation are conducted in the uninterrupted flow, but the related studies are insufficient in the interrupted flow. In this study, the modification factors during rainfall in the interrupted flow were suggested, and the factors could be used when calculating the average travel speed during rainfall in the interrupted flow. By utilizing the data that were investigated in the same road and traffic conditions and the different weather conditions (rainy day or clear day), the modification factors were founded on regression analysis of the travel speed during rainfall as a dependent variable. Modification factors was suggested in dividing peak time, non-peak time, and whole period. Based on this study, the modification factors can be used to complementing the average travel speed model for assessing the operational situation of urban streets during rainfall.

• Applied Chemistry for Engineering
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• v.17 no.1
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• pp.37-43
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• 2006

The coagulation efficacy of Al-based coagulants (such as Alum, PACS, and PACC) was investigated to ascertain removal efficiencies of turbidity and phosphate with variation of solution pH, coagulant dosages, and pre-dilution ratios. The efficacy of Al-based coagulants was maximized in the pH range of 6~9. Under the initial condition of pH 8, $10mg/L\;{PO_4}^{3-}$, and 20 NTU, Al-based coagulants exhibited a similar efficacy in the removal of turbidity, whereas the removal efficiency of phosphate was clearly dependent on the basicity of coagulants: Alum (0%) > PACS (45~50%) > PACC (70%). At high initial turbidity of 100 NTU, polymeric coagulants, such as PACS and PACC, exhibited a higher removal efficiency of turbidity compared to Alum. In comparison to direct injection of coagulants at low initial turbidity (20 NTU), 500~2000 times pre-diluted Alum, exhibited reduced coagulation efficacy; however, removal efficiencies of turbidity and phosphate increased with the increase of retention time. Pres-diluted PACC exhibited the enhanced coagulation efficacy followed by silght decrease of the removal efficiencies with increase of the retention time. At high initial turbidity of 100 NTU, pre-diluted Alum and PACC exhibited higher removal efficiencies of turbidity and phosphate.

• Journal of Ginseng Research
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• v.31 no.2
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• pp.109-116
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• 2007

Korean red ginseng has broad efficacious effects against hypertension, diabetes, nociception, and cancer, and it counteracts weakness. It has been reported that Korean red ginseng is able to normalize blood pressure, improve cholesterol and lower blood glucose levels. We have recently reported that Korean red ginseng extract (KRGE) significantly prevented rat carotid arterial thrombosis in vivo, and inhibited platelet aggregation ex vivo and in vitro in a dose-dependent manner. The purpose of this study was to examine the effects of KRGE on blood circulation in human by measuring ex vivo platelet aggregation, plasma coagulation and serum lipid profiles in healthy volunteers. Subjects were randomly divided into three groups (placebo-group, KRGE-low dose group, KRGE-high dose group). Administration of KRGE to subjects significantly inhibited ADP-induced platelet aggregations both in KRGE-low dose group from $72.79{\pm}20.53$ to $62.00{\pm}23.06%$ (p=0.0009), and in KRGE-high dose group from $75.14{\pm}21.86$ to $64.52{\pm}24.72%$ (p=0.0039), respectively. Administration of KRGE to subjects also significantly inhibited collagen-induced platelet aggregations both in KRGE-low dose group from $85.52{\pm}12.57$ to $79.62{\pm}20.47%$ (p=0.0916), and in KRGE-high dose group from $80.24{\pm}18.11$ to $70.31{\pm}25.93%$ (p=0.0565), respectively. Whereas, KRGE has no significant effects on coagulation system, such as prothrombin time (PT) and activated partial thromboplastin time (APTT), and serum lipid profiles, such as total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol and triglyceride. KRGE also has no significant effects on hematological and serum biochemical profiles. These results suggest that KRGE has a potential to improve blood circulation through antiplatelet activity in human, and KRGE intake may be beneficial for the individuals with high risks of thrombotic and cardiovascular diseases.

• The Journal of Korean Academy of Sensory Integration
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• v.12 no.2
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• pp.25-36
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• 2014

Objective : The purpose of this study is learning the characteristics of literature applying single subject researches in the field of sensory integration therapy of Korean occupational therapy and evaluating the quality level of them. Methods : Analyzed the characteristics of 17 single subject research papers (independent variable, study design, study subject, total number of session, study period, intervention time, intervention place, dependent variable, measuring tool and result) published between 2002 and 2013 using the document delivery service of Korean Society of Occupational Therapy, National Discovery for Science Leaders (NDSL), Nuri Media (DBpia), Research Information Sharing Service (RISS), Korean Studies Information Service System (KISS) and National Assembly Library and evaluated the literatures using quality evaluation scale. Results : According to the analysis result on the literature characteristics, reversal design was the most used study method. Total number of session was 10 sessions to 34 sessions. Study period was 4 weeks to 16 weeks. Intervention time was 8 minutes to 70 minutes and most interventions were done in occupational therapy room or sensory integration therapy room. According to the result of quality level evaluation, 4 papers out of 17 papers were on high level and remaining papers were on intermediate level. However, there was no study which included intervention blind. Conclusion : Suggested standards that need to be supplemented and discussions on qualitative improvement including repetitive research on the mediation effect during the application of the single subject research methodology, the securement of adequate data sections, and processing of a mediation blind. It is expected to be used as basic data for conducting a better qualitative research in the future.

• Journal of Life Science
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• v.22 no.12
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• pp.1651-1657
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• 2012

Plectin and microtubule actin cross-linking factor 1 (MACF1) are architectural proteins that contribute to the function of skeletal muscle as generators of mechanical force. However, the influence of insulin- like growth factor-I (IGF-I), a master regulator of skeletal muscle cells, on plectin and MACF1 in skeletal muscle cells has not been demonstrated. The effect of IGF-I on plectin and MACF1 gene expression was investigated by treating differentiated C2C12 murine skeletal muscle cells with 20 ng/ml of IGF-I at different time points. The IGF-I treatment increased plectin protein expression in a dose-dependent manner. The mRNA level of plectin was measured by real-time quantitative PCR to determine if plectin induction was regulated pretranslationally. IGF-I treatment resulted in a very rapid induction of plectin mRNA transcript in C2C12 myotubes. Plectin mRNA increased by 140 and 180% after 24 and 48 hours of IGF-I treatment, respectively, and returned to the control level after 72 hours of IGF-I treatment. MACF1 mRNA increased 86 and 90% after 24 and 48 hours of IGF-I treat-ment, respectively, and returned to the control level after 72 hours of IGF-I treatment. These results suggested that the plectin gene is regulated pretranslationally by IGF-I in skeletal muscle cells. In conclusion, IGF-I induces a rapid transcriptional modification of the plectin and MACF1 genes in C2C12 skeletal muscle cells and has modulating effects on a cytolinker protein as well as on contractile proteins.

• Resources Recycling
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• v.29 no.3
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• pp.11-23
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• 2020

This study aims to investigate breakage and liberation characteristics of iron ore from Shinyemi mine, Jeongseon by ball mill. Parameters of breakage functions for three grade samples of iron ore were obtained using single-sized-feed breakage test and back-calculation based on nonlinear programming. The results showed that with the increase in the grade of iron ore, the breakage rate factor decrease whereas the particle size sensitivity decreases. This results from retardation of microcrack-propagation by magnetite grain in the ore. Breakage distribution analysis showed that the breakage mechanism appear to be impact fracture dominant with the increase of grade owing to the stress distribution effect by magnetite grain. Degree of liberation (DOL) increased with the increase in grade and decrease in particle size, respectively. Using the breakage function and size-DOL relationship, a model that can predict time-dependent-DOL is established. When scale-up factors from operating condition are available, the model is expected to be capable of predicting size and DOL with time in actual mining process.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.297-305
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• 1998

This study used in vivo intracellular recording in rat hippocampus to evaluate the effect of lidocaine and MK-801 on the membrane properties and the synaptic responses of individual neurons to electrical stimulation of the commissural pathway. Cells in control group typically fired in a tonic discharge mode with an average firing frequency of $2.4{\pm}0.9$ Hz. Neuron in MK-801 treated group (0.2 mg/kg, i.p.) had an average input resistance of $3.28{\pm}5.7\;M{\Omega}$ and a membrane time constant of $7.4{\pm}1.8$ ms. These neurons exhibited $2.4{\pm}0.2$ ms spike durations, which were similar to the average spike duration recorded in the neurons of the control group. Slightly less than half of these neurons were firing spontaneously with an average discharge rate of $2.4{\pm}1.1$ Hz. The average peak amplitude of the AHP following the spikes in these groups was $7.4{\pm}0.6$ mV with respect to the resting membrane potential. Cells in MK-801 and lidocaine treated group (5 mg/kg, i.c.v.) had an average input resistance of $3.45{\pm}6.0\;M{\Omega}$ and an average time constant of $8.0{\pm}1.4$ ms. The cells were firing spontaneously at an average discharge rate of $0.6{\pm}0.4$ Hz. Upon depolarization of the membrane by 0.8 nA for 400 ms, all of the tested cells exhibited accommodation of spike discharge. The most common synaptic response contained an EPSP followed by early-IPSP and late-IPSP. Analysis of the voltage dependence revealed that the early-IPSP and late-IPSP were putative $Cl^--and\;K^+-dependent$, respectively. Systemic injection of the NMDA receptor blocker, MK-801, did not block synaptic responses to the stimulation of the commissural pathway. No significant modifications of EPSP, early-IPSP, or late-IPSP components were detected in the MK-801 and/or lidocaine treated group. These results suggest that MK-801 and lidocaine manifest their CNS effects through firing pattern of hippocampal pyramidal cells and neural network pattern by changing the synaptic efficacy and cellular membrane properties.