• Food Science and Preservation
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• v.22 no.2
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• pp.275-280
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• 2015

Among the naturally occurring antioxidants, polyphenols are widely distributed in various fruits, vegetables, wines, juices, and plant-based dietary sources and divided into several subclasses that included phenolic acid, flavonoids, stilbenes, and lignans. As part of our continuing search for bioactive food ingredients, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of the aqueous ethanolic extract from the aerial parts of Ainsliaea acerifolia were investigated in vitro. The antioxidant properties were evaluated via radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. In addition, the anti-diabetic effect of A. acerifolia extracts was tested via ${\alpha}$-glucosidase inhibitory assay. Furthermore, the total phenolic contents were determined using a spectrophotometric method. All the tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory activities. In particularly, the ${\alpha}$-glucosidase inhibitory and radical scavenging properties of the ethyl acetate (EtOAc)-soluble portion from the aerial parts of the A. acerifolia were higher than those of the other solvent-soluble portions. These results suggest that A. acerifolia could be considered a new potential source of natural antioxidants and antidiabetic ingredients. More systematic investigation of the aerial parts of A. acerifolia will be performed for the further development of anti-oxidative and antidiabetic drugs.

• Journal of Aquaculture
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• v.21 no.4
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• pp.309-316
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• 2008

Effects of the various dietary additives on growth and tolerance of abalone Haliotis discus hannai to the stresses were determined in the 16-week feeding trial. Seventy juvenile (an initial body weight of 4.2 g) abalone per container were randomly distributed into 21, 50 L plastic rectangular containers each. The six kinds of experimental diets were prepared: control (CON) with no additive, by-product of green tea (BPG), extract of figs (EF), extract of green tea (EG), commercially available product of Hearok (PH), and Haematococcus (HC). In addition, dry sea tangle (ST) was prepared to compare the efficiency of the experimental diets. Fishmeal, soybean meal and shrimp head meal were used as the protein source, and dextrin, sea tangle powder and wheat flour, and soybean oil and fish oil were used as the carbohydrate and lipid sources, respectively in the experimental diets. The experimental diets were fed to abalone once a day at a satiation level with a little leftover. The feeding trial lasted for 16 weeks. At the end of the 16-week feeding trial, abalone was exposed to the different types of stresses (air exposure, and sudden changes of rearing temperature and salinity). Survival of abalone fed the sea tangle was highest. However, weight gain of abalone fed the EF, EG and PH diets was significantly (P<0.05) higher than that of abalone fed the BPG diet or dry sea tangle. Shell length of abalone fed the all experimental diets was significantly (P<0.05) higher than that of abalone fed the dry sea tangle. Accumulated mortality of abalone fed the sea tangle was low when exposed to the different types of stresses. Also, relatively low mortality was achieved in abalone fed the HC and EF diets. In considering these results, it can be concluded that the various sources of additives is effective to improve production of abalone, and Haematococcus and extract of figs can be considered as dietary additives to improve resistance of abalone against the different types of stresses.

• Korean Journal of Remote Sensing
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• v.35 no.6_3
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• pp.1173-1185
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• 2019

We, for the first time, retrieved sulfur dioxide (SO₂) vertical column density (VCD) in industrial and volcanic areas from TROPOspheric Monitoring Instrument (TROPOMI) using the Principle component analysis(PCA) algorithm. Furthermore, SO₂ VCDs retrieved by the PCA algorithm from TROPOMI raw data were compared with those retrieved by the Differential Optical Absorption Spectroscopy (DOAS) algorithm (TROPOMI Level 2 SO₂ product). In East Asia, where large amounts of SO₂ are released to the surface due to anthropogenic source such as fossil fuels, the mean value of SO₂ VCD retrieved by the PCA (DOAS) algorithm was shown to be 0.05 DU (-0.02 DU). The correlation between SO₂ VCD retrieved by the PCA algorithm and those retrieved by the DOAS algorithm were shown to be low (slope = 0.64; correlation coefficient (R) = 0.51) for cloudy condition. However, with cloud fraction of less than 0.5, the slope and correlation coefficient between the two outputs were increased to 0.68 and 0.61, respectively. It means that the SO₂ retrieval sensitivity to surface is reduced when the cloud fraction is high in both algorithms. Furthermore, the correlation between volcanic SO₂ VCD retrieved by the PCA algorithm and those retrieved by the DOAS algorithm is shown to be high (R = 0.90) for cloudy condition. This good agreement between both data sets for volcanic SO₂ is thought to be due to the higher accuracy of the satellite-based SO₂ VCD retrieval for SO₂ which is mainly distributed in the upper troposphere or lower stratosphere in volcanic region.

• Journal of Families and Better Life
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• v.27 no.6
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• pp.65-82
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• 2009

The following research aimed to determine the effect of stress among middle school students on their addiction to the Internet. This research's target was a group of male students who had a high probability of getting addicted to the Internet while playing c/t games. The study distributed 357 questionnaires and used 340 copies, which meant discarding 17 copies that were considered inadequate. The research results are as follows: First, there appeared subordinate factors in the stress suffered by the students. These included stress from their families, from conflicts with their teachers, from the living environment, current schoolwork and future course in college, insecurity over their physical appearance, bullying from other students, and relationships with friends. Among these factors, stress caused by conflicts with teachers and family was the most frequently cited, while stress from their friends was the least cited. The motive in using the Internet was found to be bound with several factors. These include: a form of diversion, a way to communicate with others, a means in coping with loneliness, a source of news and information, a form of passing away time, a kind of habit, and others. Among these motives, passing away time and indulging a habit were cited the most, followed by news and information search, and a form of diversion. Second, as a subordinate factor in Internet addiction, the following were cited: formation of tolerance, health issues, occurrence of problems related to daily life, satisfaction or a pleasant sensation, withdrawal, cover-up on the use of the Internet, and formation of virtual interpersonal relationships, and others. Among these, the formation of tolerance came out the highest, followed by health issues, daily life, and problems related to daily life. Third, in terms of the effects of stress on the motive in using the Internet, the research found that the more the students felt stressed out by conflicts with their teachers and family, the more they tended to use the Internet to communicate with others, to cope with loneliness, to obtain newsI and information, to passawaytime, and to indulge a habit Also, the more they felt stressed out by the living environment, the more they tended to use the Internet to communicate with others, to cope with loneliness, and use news and information. The more they felt stressed out by their schoolwork and future course in college, they tended to use the Internet as a form of diversion and to secure news and information. The more they felt stressed out by their insecurity over their physical appearance and being victimized by bullies, the more they tended to use the Internet to cope with loneliness. Fourth, as for the effect of several variables on student addiction to the Internet, the study found that the more students felt stressed out by their living environment, by schoolwork and future course in college, by their physical appearance, and bullying from other students, the more they used the Internet as a form of diversion, a communication tool, and as a means of passing away time or indulging a habit. The study came up with the finding that the more the students used the computer and the Internet, the probability of their getting addicted to the Internet got higher.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.113-127
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• 2005

Cretaceous intrusive and extrusive rocks are widely distributed in the southwestern part of the Korean peninsula, possibly the result of intensive magmatism which occurred in response to subduction of the western proto-Pacific plate beneath the north-eastern part of the Eurasian plate. Geochemical and petrological study on the Cretaceous granitic rocks were carried out in order to constrain the petrogenesis of the granitic magma and to establish the paleotectonic environment of the area. Whole rock chemical data of the granitic rocks from the study area indicate that the all the rocks have characteristics of calc-alkaline series in the subalkaline field. The overall geochemical features show systematic variations in each granitic body, but the source materials of each granitic body are thought to have been different in their chemical composition. Higher values of $Fe_2O_3/FeO$ of the granitic rocks in the western area suggest that the granitoids had been solidified under highly oxidizing environment. The granitic bodies in the eastern area also show higher contents of Li, Ni, Co, Sr, Cr, Sc and lower Rb and Nb compared to the those of the western area. Chondrite normalized REE patterns show generally enriched LREE and strong negative Eu anomalies in the western wet while slight to flat Eu anomalies in the east-ern area. The REE and $(La/Lu)_{CN}$ of the granites are $60{\~}499ppm$ and $8.9{\~}66$ correspond to the range of the continental margin granite. On the ANK vs. ACNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type, VAG and syn-collision granite. Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at continental margin during the subduction of proto-Pacific plate.

• Economic and Environmental Geology
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• v.44 no.1
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• pp.83-94
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• 2011

Extra heavy oil reservoirs are distributed over the world but most of them is deposited in the northern part of the Orinoco River in Venezuela, in the area of 5,500 $km^2$, This region, which has been commonly called "the Orinoco Oil Belt", contains estimated 1.3 trillion barrels of original oil-in-place and 250 billion barrels of established reserves. The Venezuela extra heavy oil has an API gravity of less than 10 degree and in situ viscosity of 5,000 cP at reservoir condition. Although the presence of extra heavy oil in the Orinoco Oil Belt has been initially reported in the 1930's, the commercial development using in situ cold production started in the 1990's. The Orinoco heavy oil deposits are clustered into 4 development areas, Boyaco, Junin, Ayachoco, and Carabobo respectively, and they are subdivided into totally 31 production blocks. Nowadays, PDVSA (Petr$\'{o}$leos de Venzuela, S.A.) makes a development of each production block with the international oil companies from more than 20 countries forming a international joint-venture company. The Eastern Venezuela Basin, the Orinoco Oil Belt is included in, is one of the major oil-bearing sedimentary basins in Venezuela and is first formed as a passive margin basin by the Jurassic tectonic plate motion. The major source rock of heavy oil is the late Cretaceous calcareous shale in the central Eastern Venezuela Basin. Hydrocarbon materials migrated an average of 150 km up dip to the southern margin of the basin. During the migration, lighter fractions in the hydrocarbon were removed by biodegradation and the oil changed into heavy and/or extra heavy oil. Miocene Oficina Formation, the main extra heavy oil reservoir, is the unconsolidated sand and shale alternation formed in fluvial-estuarine environment and also has irregularly a large number of the Cenozoic faults induced by basin subsidence and tectonics. Because Oficina Formation has not only complex lithology distribution but also irregular geology structure, geological evolution and characteristics of the reservoirs have to be determined for economical production well design and effective oil recovery. This study introduces geological formation and evolution of the Venezuela extra heavy oil reservoirs and suggest their significant geological characteristics which are (1) thickness and geometry of reservoir pay sands, (2) continuity and thickness of mud beds, (3) geometry of faults, (4) depth and geothermal character of reservoir, (5) in-situ stress field of reservoir, and (6) chemical composition of extra heavy oil. Newly developed exploration techniques, such as 3-D seismic survey and LWD (logging while drilling), can be expected as powerful methods to recognize the geological reservoir characteristics in the Orinoco Oil Belt.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.1-9
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• 2006

Peroxiredoxins (Prxs) are ubiquitously distributed and play important functions in diverse cellular signaling systems. The proteins are largely classified into three groups, such as typical 2-Cys Prx, atypical 2-Cys Prx, and 1-Cys Prx, that are distinguished by their catalytic mechanisms and number of Cys residues. From the three classes of Prxs, the typical 2-Cys Prx containing the two-conserved Cys residues at its N-terminus and C-terminus catalyzes $H_2O_2$ with the use of thioredoxin (Trx) as an electron donor. During the catalytic cycle, the N-terminal Cys residue undergoes a peroxide-dependent oxidation to sulfenic acid, which can be further oxidized to sulfinic acid at the presence of high concentrations of $H_2O_2$ and a Trx system containing Trx, Trx reductase, and NADPH. The sulfinic acid form of 2-Cys Prx is reduced by the action of sulfiredoxin which requires ATP as an energy source. Under the strong oxidative or heat shock stress conditions, 2-Cys Prx in eukaryotes rapidly switches its protein structure from low-molecular-weight species to high-molecular-weight protein structures. In accordance with its structural changes, the protein concomitantly triggers functional switching from a peroxidase to a molecular chaperone, which can protect its substrate denaturation from external stress. In addition to its N-terminal active site, the C-terminal domain including 'YF-motif' of 2-Cys Prx plays a critical role in the structural changes. Therefore, the C-terminal truncated 2-Cys Prxs are not able to regulate their protein structures and highly resistant to $H_2O_2$-dependent hyperoxidation, suggesting that the reaction is guided by the peroxidatic Cys residue. Based on the results, it may be concluded that the peroxidatic Cys of 2-Cys Prx acts as an '$H_2O_2$-sensor' in the cells. The oxidative stress-dependent regulation of 2-Cys Prx provides a means of defense systems in cells to adapt stress conditions by activating intracellular defense signaling pathways. Particularly, 2-Cys Prxs in plants are localized in chloroplasts with a dynamic protein structure. The protein undergoes conformational changes again oxidative stress. Depending on a redox-potential of the chloroplasts, the plant 2-Cys Prx forms super-molecular weight protein structures, which attach to the thylakoid membranes in a reversible manner.

• Journal of the Korean earth science society
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• v.34 no.4
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• pp.313-328
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• 2013

Jurassic granitoids in the northeastern part of the Yeongnam Massif are possibly the result of intensive magmatic activities that occurred in response to subduction of the proto-Pacific plate beneath the northeast portion of the Eurasian plate. Geochemical studies on the granitic rocks are carried out in order to constrain the petrogenesis of the granitic magma and to establish the paleotectonic environment of the area. Whole rock chemical data of the Uljin granitoids in the northeastern part of the Yeongnam Massif indicate that all of the rocks have the characteristics of calcalkaline series in subalkaline field. The overall major element trends show systematic variations in each granitic body, but the source materials of each granitoids seem to have different chemical composition. The Uljin granitoids are different from other granitic rocks, which distributed vicinity of the study area, in the contents of $Al_2O_3$ and trace elements such as Cr, Co, Ni, Sr, Y and Nb. The Uljin granitoids have geochemical features similar to slab-derived adakites such as high $Al_2O_3$, Sr contents and high Sr/Y, La/Yb ratios, but they have low Y and Yb contents. The major ($SiO_2$, $Al_2O_3$, MgO) and trace element (Sr, Y, La, Yb) contents of the Uljin granitoids fall well within the adakitic field. The Uljin granitoids have similar geochemical characteristics, paleotectonic environments and intrusion ages to those of the Yatsuo plutonic rocks of Hida belt located on northwestern part of Japan. Chondrite normalized REE patterns show generally enriched LREEs ($(La/Yb)_{CN}=10.6-103.4$) and are slight negative to flat Eu anomalies. On the ANK vs. A/CNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type and volcanic arc granite (VAG). Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at the continental margin during the subduction of Izanagi plate in Jurassic period.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.1
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• pp.1-12
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• 1991

An experiment has been carefully designed and performed to verify the theory for the echointergration technique of estimating the density of fish school by the use of steel spheres in a laboratory tank. The spheres used to simulate a fish school were randomly distributed throughout the insonified volume to produce the acoustic echoes similar to those scattered from real fish schools. The backscattered echoes were measured as a function of target density at tow frequencies of 50kHz and 200kHz. Data acquisition, processing and analysis were performed by means of the microcomputer-based sonar-echo processor including a FFT analyzer. Acoustic scattering characteristics of a 36cm mackerel was investigated by measuring fish echoes with frequencies ranging from 47.8kHz to 52.0kHz. The fluctuation of bottom echoes caused by the effects of fish-school attenuation and multiple scattering which occurred in dense aggregations of fishes was also examined by analyzing the echograms of sardine schools obtained by a 50kHz telesounder in the set-net's bagnet, and the echograms obtained by a scientific echo sounder of 50kHz in the East China Sea, respectively. The results obtained can be summarized as follows: 1. The measured and the calculated echo shapes on the steel sphere used to simulate a fish school were in close agreement. 2. The waveform and amplitude of echo signals by a mackerel without swimbladder fluctuated irregularly with the measuring frequency. 3. When a collection of 30 targets/m super(3) lied the shadow region behind another collection of 5 targets/m super(3), the mean losses in echo energy for the 30 targets/m super(3) were about -0.4dB at 50kHz and about -0.2dB at 200kHz, respectively. 4. In the echograms obtained in the East China Sea, the bottom echoes fluctuated remarkably when the dense aggregations of fish appeared between transducer and seabed. Especially, in the case of the echograms of sardine school obtained in a set-net's bagnet, the disappearance of bottom echoes and the lengthening of the echo trace by fish aggregations were observed. Then the mean density of the sardine school was estimated as 36 fish/m super(3). It suggests that when the distribution density of fishes in oceans is greater than this density, the effects of fish-school attenuation and multiple scattering must be taken into account as a possible source of error in fish abundance estimates. 5. The relationship between mean backscattering strength (, dB) and target density ($\rho$, No./m super(3)) were expressed by the equations: =-46.2+13.7 Log($\rho$) at 50kHz and =-43.9+13.4 Log($\rho$) at 200kHz. 6. The difference between the experimentally derived number and the actual number of targets gradually decreased with an increase in the target density and was within 20% when the density was 30 targets/m super(3). From these results, we concluded that when the number of targets in the insonified volume is large, the validity of the echo-integration technique of estimating the density of fish schools could be expected.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.30-36
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• 2006

Japan's first pilot-scale $CO_2$ sequestration experiment has been conducted in Nagaoka, where 10400 t of $CO_2$ have been injected in an onshore aquifer at a depth of about 1100 m. Among various measurements conducted at the site for monitoring the injected $CO_2$, we conducted time-lapse crosswell seismic tomography between two observation wells to determine the distribution of $CO_2$ in the aquifer by the change of P-wave velocities. This paper reports the results of the crosswell seismic tomography conducted at the site. The crosswell seismic tomography measurements were carried out three times; once before the injection as a baseline survey, and twice during the injection as monitoring surveys. The velocity tomograms resulting from the monitoring surveys were compared to the baseline survey tomogram, and velocity difference tomograms were generated. The velocity difference tomograms showed that velocity had decreased in a part of the aquifer around the injection well, where the injected $CO_2$ was supposed to be distributed. We also found that the area in which velocity had decreased was expanding in the formation up-dip direction, as increasing amounts of $CO_2$ were injected. The maximum velocity reductions observed were 3.0% after 3200 t of $CO_2$ had been injected, and 3.5% after injection of 6200 t of $CO_2$. Although seismic tomography could map the area of velocity decrease due to $CO_2$ injection, we observed some contradictions with the results of time-lapse sonic logging, and with the geological condition of the cap rock. To investigate these contradictions, we conducted numerical experiments simulating the test site. As a result, we found that part of the velocity distribution displayed in the tomograms was affected by artefacts or ghosts caused by the source-receiver geometry for the crosswell tomography in this particular site. The maximum velocity decrease obtained by tomography (3.5%) was much smaller than that observed by sonic logging (more than 20%). The numerical experiment results showed that only 5.5% velocity reduction might be observed, although the model was given a 20% velocity reduction zone. Judging from this result, the actual velocity reduction can be more than 3.5%, the value we obtained from the field data reconstruction. Further studies are needed to obtain more accurate velocity values that are comparable to those obtained by sonic logging.