• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.3
• /
• pp.315-323
• /
• 1997

Central tryptaminergic system has been shown to play an important role in the regulation of renal function: $5-HT_1(5-hydroxytryptamine_1)$ receptors might seem to mediate the diuresis and natriuresis, whereas the $5-HT_2\;and\;5-HT_3$ receptors mediate the antidiuretic and antinatriuretic effects. This study attempted to delineate the role of central $5-HT_{1A}$ subtype in the regulation of rabbit renal function by observing the renal effects of intracerebrovent-ricularly(icv)-administered PAPP(p-aminorhenylethyl-m-trifluoromethytphenyl piperazine, LY165163), a selective agonist of $5-HT_{1A}$ receptors. PAPP in doses ranging from 40 to $350{\mu}g/kg$ icv induced significantly diuresis, natriuresis, and kaliuresis, along with increased renal perfusion and glomerular filtration. Systemic blood pressure was also increased. Free water reabsorption$(T^cH_2O)$, a measure of ADH(antidiuretic hormone) secretion, was increased also. Intravenous $350{\mu}g/kg$ of PAPP elicited antidiuresis and antinatriuresis together with decreased blood pressure, thus indicating that the effects of icv PAPP were brought about through the central mechanisms, not by direct peripheral effects of the drug on kidney. Ketanserin, a selective $5-HT_2$ antagonist, $40{\mu}g/kg$ icv, did not affect the renal effects of the icv PAPP. Methysergide, a non-selective $5-HT_1$ antagonist, also did not block the renal functional responses by the icv PAPP. NAN-190, a $5-HT_{1A}$ antagonist, also did not antagonized the renal action of the icv PAPP. However the increased free water reabsorption was abolished by both methysergide or ketanserin pretreatment. The increments of blood pressure by icv PAPP was blocked only by NAN-190 pretreatment. These observations suggest that the central $5-HT_{1A}$ receptor might be involved in the central regulation of rabbit renal function by exerting the diuretic and natriuretic influences.

• The Journal of Engineering Geology
• /
• v.24 no.4
• /
• pp.525-534
• /
• 2014

Environmental problems typically occurring in abandoned mine lands (AML) include: contaminated and acidic surface water and groundwater; stockpiled waste rock and mill tailings; and ground subsidences due to mining operations. This study examines the effectiveness of various geophysical techniques for mapping potential hazard and contaminated zones. Four AML sites with sedimentation contamination problems, acid mine drainage (AMD) channels, ground subsidence, manmade liner leakage, and buried mine tailings, were selected to examine the applicability of various geophysical methods to the identification of the different types of mine hazards. Geophysical results were correlated to borehole data (core samples, well logs, tomographic profiles, etc.) and water sample data (pH, electrical conductivity (EC), and heavy metal contents). Zones of low electrical resistivity (ER) corresponded to areas contaminated by heavy metals, especially contamination by Cu, Pb, and Zn. The main pathways of AMD leachate were successfully mapped using ER methods (low anomaly peaks), self-potential (SP) curves (negative peaks), and ground penetrating radar (GPR) at shallow penetration depths. Mine cavities were well located based on composite interpretations of ER, seismic tomography, and well-log records; mine cavity locations were also observed in drill core data and using borehole image processing systems (BIPS). Damaged zones in buried manmade liners (used to block descending leachate) were precisely detected by ER mapping, and buried rock waste and tailings piles were characterized by low-velocity zones in seismic refraction data and high-resistivity zones in the ER data.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.33 no.3
• /
• pp.173-182
• /
• 1997

This study is a basic research in purse seine fishery : on the behaviour of fish schools of tilapia Tilapia mossambica in the process of catch of the purse seine fishing method. The experiment was carried out for the mackerel purse seine which using of power block by fishing fleet system in the near sea of Cheju Island and as a forecast in the near future on the purse seine fishing, using of triplex net winch by one boat system in the near sea of Norway. These model purse seines were made of the scale of 1/180 of its full scale. The model purse seine test on the escaping behaviour of fish school by gap, area reducing of gap and tension of purse line was carried out in the stagnant water of experimental water tank. Designing and testing for the model purse seines were based on the Tauti's law. The results obtained were as follows : 1. When the time for the completing of pursing was 20 minutes, average swimming speed of fish school through a gap was 9.71cm/sec for powerblock seine and 9.97cm/sec for triplex seine. 2. In the case of pursing time in actual value was 20minutes, at 50 percent of the pursing, swimming behaviour of fish school in purse seine was 10% to I section, 80% to II section, 10% to III sectional direction for powerblock seine and a similar tendency for triplex seine. 3. In the case of pursing time in actual value was 20 minutes, at the time of 10 minutes have proceeded since then, area reducing rate of gap of the seine in projected front view was 63.5% for powerblock seine and 67.5% for triplex seine. 4. In the case of pursing time in actual value was 20 minutes, escaping rate of fish school by gap in projected front view was 70% for powerblock seine and 30% for triplex seine. Maximum tension of purse line was about 8.1 tons for powerblock seine and about 8.3 tons for triplex seine.

• Applied Biological Chemistry
• /
• v.43 no.2
• /
• pp.141-147
• /
• 2000

Interrelation between the antioxidative activity of hot-water extracts of 130 medicinal plants and their cellular antimutagenic activity was investigated. Antioxidative activity was evaluated by assaying electron-donation to DPPH free radical and scavenging of hydroxyl radical $({\cdot}OH)$ generated through Fenton rection, respectively. All medicinal plants examined in this study exhibited markedly electron-donating ability and radical scavenging ability in each assay system. The results demonstrated the fact that Pilbal (Piper longum L.) is the strongest in electron-donating activity, on the other hand, that Seokgok (Dendrobium moniliforme L.) is the strongest in ${\cdot}OH$ scavenging activity. When evaluated their antioxidative activities, 24 medicinal plants including Jimo (Anemarrhena asphodeloides Bunge) were found to be the medicinal plants carrying strong antioxidative activity, which exhibited more than 50% activity compared to the control group in both electron-donating and free radical scavenging. The experiment was also performed to examine whether 11 medicinal plants having significant antimutagenicity damage DNA in the presence of $Cu^{2+}$, showing the fact that all samples tested, except Taeksa (Alisma canaliculatum All. Br.), Paekjain (Nitraria sibirica Pall) and Ohyak (Lindera strychifolia Sieb. et Zucc. Villar) are capable of inducing DNA strand break. We also found that Taeksa and Paekjain strongly block DNA strand break induced by chemical mutagen mitomycin C.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.27 no.1
• /
• pp.62-70
• /
• 1985

The purpose of this study is to investigate the basic data such the total, the daily maximum, and the peak stage of consumptive use of water and also the soil moisture extraction pattern for irrigation plan of tobacco during the growing period. The plots at which this study was conducted are divided into three fertilization levels of 30g, 60g, and 90g. Each block for three levels is divided as vinyl mulching and irrigation plot, vinyl mulching and nonirrigation plot, and nonmulching and irrigation plot. The results obtained are summarized as follows: 1. The evapotranspiration amount of mulching-irrigation plots are similar to that of mulching-nonirrigation plots. While, the evapotranspiration amount of mulching plots are different obviousely from that of nonmulching plots. Therefore, a significance was recognized between the mulching plots and the nonmulching plots. 2. The amount of evapotranspiration in case of 60g and 90g fertilization level was larger than that of 30g. But the 60g plots and the 90g plots showed little differences. 3. In the total amount of evapotranspiration for each of the experimental plots during the growing period, nonmulching-irrigation plot showed the largest value of 332.9mm, second the mulching-irrigation plot, 284. 9mm, and the mulching-nonirrigation plot, the smallest as 255. 9mm. 4. In the monthly average amount of evapotranspiration for each of the treatment plots, the mulching-irrigation the mulching-nonirrigation, and the nonmulching-irrigation plot showed 3. 6mm, 3. 2mm and 4. 2mm respectively. The daily maximum amount of evapotranspiration showed 5. 1mm, 4. 5mm, and 6.4mm for the mulching-irrigation, the mulching-nonirrigationl, and the nonmulching-irrigation plot respectively. 5. It was confirmed that the higher correlationship exists between the weight of dried leaves and the amount of evapotranspiration, and between the weight of dried leaves and the coefficient of evapotranspiration with the function of logarithms. The coefficient of evapotranspiration have a tendency to increase in proportion to the leaf area index. 6. The maximum coefficient of evapotranspration and the largest leaf area index showed 1. 45 and 5.5 respectively. The stage appeared maximum values was assumed to be before and after flowering. 7. The soil moisture extraction pattern has changed by the depth of root zone for the tobacco's growing. The soil moisture extraction influenced on the 20cm depth of soil after 15 days passed, the 30cm depth after 25 days passed and the whole root zone after 45 days passed from planting. It was shown in the only mulching-irrigation plot after S5days passed from planting that the rate of soil moisture extraction of 20cm layer was larger than that of 10cm layer.

• Membrane Journal
• /
• v.18 no.3
• /
• pp.234-240
• /
• 2008

This work demonstrates the preparation of proton conducting crosslinked polymer electrolyte membranes by blending polystrene-b-poly(hydroxyethyl acrylate) (PS-b-PHEA) and poly(vinyl alcohol) (PVA) at 1 : 1 wt ratio. The PHEA block of the diblock copolymer was crosslinked with PVA using sulfosuccinic acid (SA) via the esterification reaction between -OH of membrane and -COOH of SA, as confirmed by FT-IR spectroscopy. Ion exchange capacity (IEC) continuously increased from 0.14 to 0.91 meq/g with increasing concentrations of SA, due to the increasing portion of charged groups in the membrane. In contrast, the water uptake increased up to 20.0 wt% of SA concentration above which it decreased monotonically. The membrane also exhibited a maximum proton conductivity of 0.024 S/cm at 20.0 wt% of SA concentration. The maximum behavior of water uptake and proton conductivity is considered to be due to competitive effect between the increase of ionic sites and the crosslinking reaction according to the SA concentration.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.62 no.5
• /
• pp.39-46
• /
• 2020

This study evaluated the nitrogen oxide (NO_x) removal efficiency by air purification concrete blocks with titanium dioxide (TiO₂). The concrete in the mixtures had a 30% water:cement ratio, to which TiO₂ was added at 0%, 5%, and 10% of cement weight. The compressive strength reduction rate and removal efficiency of NO_x were investigated. The result of the compressive strength test in the study indicated that addition rate of TiO₂ did not lead to signifcant effect. In terms of the average removal efficiency of NO_x, mix No. 1 using a TiO₂ mixing ratio of 0% had a removal efficiency of 0.57% on average; thus, the removal effect w as not significant. For the other samples prepared by mixing, the average removal efficiencies for mix No. 2 (5% TiO₂) were 58.86% and 62.05% for normal and washing surface treatments, respectively, and those of sample No. 3 (10% TiO₂) were 59.94% and 67.61%. mixs No. 4 (5%) and No. 5 (10%), in which TiO₂ diluted with distilled water was sprayed onto the block surface, had an average NO_x removal efficiency of 61.72% and 68.48%, respectively. In terms of NOx removal efficiency, Mixs No. 3 and No. 5 with 10% TiO₂ were better than Mixs No. 2 and No. 4 with 5% TiO₂. In addition, analyzing the NO_x removal efficiency results from the fixing method, it was capable to apply mixing (washing) and the diluted spray methods. Therefore, it was found that the diluted spray method applied in this study can be employed in any manufacture of air purification concrete blocks.

• Journal of Conservation Science
• /
• v.31 no.2
• /
• pp.95-104
• /
• 2015

Excavated archaeological cast iron objects in improper storage are quickly corroded and disintegrated into block and powder finally. Hence desalination treatment which is a way of removing internal corrosive factors, especially chloride ion, is an important process. But desalination is often omitted or objects are dehydrated by alcohol because the destruction of objects could occur during desalting. Although current desalting methods mostly use an aqueous alkali solution, $OH^-$ ions of water could accelerate corrosion and broaden internal cracks cause of high surface tension. Therefore this study experimented desalting using ethyl alcohol, which is low surface tension, to investigate an effect of desalination. As a result, desalting using ethyl alcohol showed the similar or more effective results of desalting using water. In addition, as aspects of desalting safety, ethyl alcohol desalting method was smaller destruction of objects and extraction of Fe from the objects than the aqueous alkali solution. However, this study explored the possibility of desalting methods using organic solvent in fieldwork, so the results would provide basic date for making the safe and effective desalting method for archaeological cast iron objects through further experiments.

• Korean Chemical Engineering Research
• /
• v.44 no.2
• /
• pp.172-178
• /
• 2006

Mesoporous silicate materials have been used as adsorbents for the removal of heavy metals from water by introducing functional groups such as thiol and amine. In this research, it was investigated whether surfactants used as templating agents in synthetic processes can act as adsorption sites for heavy metals. Three mesoporous silicates-SBA-15, MCM-41, and HMS were synthesized using, respectively, block copolymer, hexadecyltrimethylammoniumbromide (HDTMA), and dodecyamine as surfactants. X-ray diffraction and $N_2$ gas adsorption analysis confirmed that the mesoporous silicates were well prepared and FT-IR spectra resulted in the existence of the surfactants in as-synthesized mesoporous silicates and the removal of surfactants after calcination. The interactions between $Pb^{2+}$ ions and the mesoporous silicate materials with/without surfactants were observed. In adsorption kinetic experiments, it revealed that the calcined mesoporous silicates and the surfactant-loaded SBA-15 almost had no adsorption capacity for $Pb^{2+}$ ions. In contrast, the surfactant-loaded MCM-41 and HMS showed, respectively, the adsorption capacities of 26.60 and 115.16 mg/g which were acquired through the fits of adsorption kinetic data to the pseudo second order kinetic model. The adsorption capacities were comparable to those of other mesoporous adsorbents for heavy metals.

• Journal of the Korean Chemical Society
• /
• v.18 no.2
• /
• pp.97-109
• /
• 1974

The crystal and molecular structure of sulfaguanidine monohydrate, $C_7H_{10}N_4O_2S{\cdot}H_2O$, was determined from visually estimated intensity data from Weissenberg photographs. The crystal data are monoclinic, space group $P2_1$/c with four molecules in a unit cell of dimensions, ${\alpha}=7.57{\pm}0.03,\;b=5.44{\pm}0.02,\;c=24.76{\pm}0.06{\AA},\;{\beta}=91.0{\pm}0.2^{\circ}$. The structure has been solved by an interpretation of a Patterson map and with a help of a direct procedure on a projection. The parameters were refined isotropically by block-diagonal least-squares methods using 1542 observed independent reflections to give R = 0.14. By hydrogen bonding a guanidyl nitrogen of a sulfaguanidine molecule is linked to the sulfonyl oxygens of the other molecules indirectly through two different water molecules. The role of water molecule is both a donor and an acceptor in hydrogen-bonding formation and these hydrogen bonds are tetrahedrally oriented. The hydrogen-bonding networks form infinite molecular layers parallel to (001) plane.