• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1133-1137
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• 2011

A novel technique for the fabrication of a glass micropipette-based thermal sensor was developed utilizing inexpensive thermocouple materials. Thermal fluctuation with a resolution of ${\pm}0.002$ K was measured using the fabricated thermal probe. The sensors comprise unleaded low-melting point solder alloy (Sn) as a core metal inside a borosilicate glass pipette coated with a thin film of Ni, creating a thermocouple junction at the tip. The sensor was calibrated using a thermally insulated calibration chamber, the temperature of which can be controlled with a precision of ${\pm}0.1$ K and the thermoelectric power (Seebeck coefficient) of the sensor was recorded from 8.46 to $8.86{\mu}V$/K. The sensor we have produced is both cost-effective and reliable for thermal conductivity measurements of micro-electromechanical systems (MEMS) and biological temperature sensing at the micron level.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.5
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• pp.259-268
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• 2017

This paper proposes a hydrogen-based social economy derived from fuel cells capable of replacing fossil fuels and resolving global warming, It thus provides an entry for developing economically feasible social configurations to make use of bio-hydrogen production systems. Bio-hydrogen production works from the principle that microorganisms decompose water in the process of converting CO to $CO_2$, thereby producing hydrogen. This study parts from an analysis of an existing 157-ton class NA1 bio-hydrogen reactor that identifies the state of feedstock and reactor conditions. Based on this analysis, we designed a 1-ton class bio-hydrogen reactor process simulator. We carried out thermal analyses of biological heat reactions, sensible heat, and heat radiation in order to calculate the thermal load of each system element. The reactor temperature changes were determined by modeling the feed mixing tank capacity, heat exchange, and heat storage tank. An analysis was carried out to confirm the condition of the feed mixing tank, heat exchanger, heat storage tank capacity as well as the operating conditions of the system so as to maintain the target reactor temperature.

• Animal cells and systems
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• v.14 no.4
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• pp.315-322
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• 2010

We studied and compared the age structure, body size, and growth rates of field populations of two Korean salamander species (Hynobius yangi and Hynobius quelpaertensis) to elucidate important aspects of basic population dynamics of these two endemic Hynobius species. In both populations, females were sexually mature at three years of age, while H. yangi and H. quelpaertensis males matured at two and three years of age, respectively. Both males and females of H. yangi and H. quelpaertensis attained a maximum age of 11 years and 10 years, respectively. In both species, the snout-vent length (SVL) and body weight (BW) of the females were greater than those of the males. The SVL, BW, and asymptotic SVL of both male and female H. yangi were smaller than those of H. quelpaertensis. The adult growth rates after sexual maturation of male and female H. yangi were lower than those of H. quelpaertensis, possibly resulting in the smaller body size of the former, although overall growth coefficients were not significantly different between the two species. We also compared the age structure and growth rates of three Korean and three Japanese species of Hynobius.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1303-1309
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• 2012

A novel ligand N,N'-(2,6-pyridinedicarbonyl)bis[N-(carboxymethyl)] (L1) was designed and synthesized. Four co-luminescence groups of Sm-La-pyridyl carboxylic acids systems were researched, which are $K_4Sm_{(1-x)}-La_x(L_1)Cl_3{\cdot}y_1H_2O$, $K_4Sm_{(1-x)}La_x(L_2)Cl_3{\cdot}y_2H_2O$, $K_6Sm_{2(1-x)}La_{2x}(L_3)Cl_6{\cdot}y_3H_2O$, $K_4Sm_{(1-x)}La_x(L_4)Cl_3{\cdot}y_4H_2O$. The results indicated the addition of La(III) could sensitize the luminescence of Sm(III) obviously in a certain range, enhancing emission intensity of Sm-pyridyl carboxylic acids relative to the undoped ones. The optimal mole percentages of La(III) in the mixed ions for $L_1$, $L_2$, $L_3$, $L_4$ were confirmed to be 0.6, 0.5, 0.3, 0.6, respectively. The mechanism of the fluorescence enhancement effect was discussed in detail. Furthermore, the binding interaction of $K_4Sm_{0.4}La_{0.6}(L_4)Cl_3{\cdot}5H_2O$ with bovine serum albumin (BSA) have been investigated due to its potential biological activity. The binding site number n was equal to 1.0 and binding constant $K_a$ was about $2.5{\times}10^5\;L{\cdot}mol^{-1}$.

• Journal of Ginseng Research
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• v.35 no.2
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• pp.138-148
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• 2011

Exponential rise in the use of mobile communication devices has generated health concerns due to radiofrequency (RF) exposure due to its close proximity to the head. Calcium binding proteins like calretinin regulate the levels of calcium ($Ca^{2+}$) which plays an important role in biological systems. Ginseng is known for maintaining equilibrium in the human body and may play a beneficial radioprotectant role against electromagnetic field (EMF) exposure. In the present study, we evaluated the radioprotective effects of red ginseng (RG) extract in a mouse model. Calretinin (CR) expression was measured using a free-floating immunohistochemical method in the hippocampus of mice after 835 MHz EMF exposure for 5 h/d for 5 d at specific absorption rate=1.6 W/kg for the different experimental groups. The control animals were treated with NaCl while the experimental animals received 10 mg/kg ginseng, or 30 mg/kg; EMF exposed mice were also treated with NaCl, 10 mg/kg ginseng (E10), or 30 mg/kg (E30). Decreases in CR immunoreactivity (IR) along with loss of CA1 and CA3 interneurons and infragranular cells were observed in the ENaCl group while such losses were not observed in the E10 and E30 groups. CR IR significantly increased in the RG-treated group compared to control and EMF-exposed groups treated with NaCl. The study demonstrates that RG extract can serve as a radioprotective agent that maintains $Ca^{2+}$ homeostasis and prevents neuronal loss in the brain hippocampal region caused by RF exposure.

• Animal cells and systems
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• v.15 no.1
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• pp.37-43
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• 2011

The Korean freshwater crayfish, Cambaroides similis, has recently suffered from range reduction and habitat degradation caused by environmental changes and water pollution. For the conservation and restoration of this species, it is necessary to understand the current population structures of Korean C. similis using estimation of their genetic variation. In this study, eight micro satellite loci were developed and characterized from 49 individuals collected from four locations: one population from Mt. Bukhan (BH) and three populations from Mt. Gwanak (GA) in Seoul, Korea. As a result, the number of alleles per locus ranged from 2 to 12. The observed heterozygosities and expected heterozygosities ranged from 0.000 to 0.833 and from 0.125 to 0.943, respectively, and the former values were significantly lower than the latter ones expected under the Hardy-Weinberg equilibrium. No significant linkage disequilibrium was revealed between any of the locus pairs after Bonferroni correction. From the pairwise Fst results over all samples, higher differentiation between GA-BH population pairs (mean 0.1789) was observed than between GA population pairs (mean 0.0454). This was also supported by Mantel's test showing that the genetic distances of these crayfish populations were significantly correlated with geographic distances. This result may show the regional differentiation caused by restricted gene flow between northern (BH) and southern (GA) populations within Seoul. These micro satellite markers have the potential for use in analyses of the genetic diversity and population structure of C. similis species, with implications for its conservation and management plans.

• Korean Journal of Medicinal Crop Science
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• v.8 no.4
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• pp.291-296
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• 2000

To evaluate the biological effects of boxthorn (Lycium chinense Mill.) extracts on the immune response systems, the mitogenic effects were tested by LPS (lipopolysaccharide) and Con A (concanavalin A) using water extracts from various parts of Lycium chinense Mill. The proliferation of B-lymphocytes which were activated by the mitogen, LPS, was markedly increased in the concentration of 0.1mg/ml to 0.5mg/ml, but inhibited in more than 0.5mg/ml. It increased only proliferation of B-lymphocytes but not that of T-lymphocytes by Con A. There was no difference between boxthorn species in immune response. Water extracts of various parts in boxthorn enhanced the humoral immune response which was related to B-lymphocytes.

• Korean Journal of Medicinal Crop Science
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• v.17 no.6
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• pp.379-387
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• 2009

The aim of this investigation was to examine the influence of extrusion on dietary fiber profile and the content of bioactive compounds, rutin and quercetin in young sprout, whole seed, and matured stem of Tartary buckwheat. WSI(water soluble index) is increased by a function of both screw profile and process temperature, compared to control in different parts of Buckwheat. Also, WSI of ME is increased more than 5.2 times in grain, compared to that of control. The effect of precooking by extrusion on the dietary fiber profile of buckwheat flour was evaluated. Precooking by extrusion significantly increased SDF in flour, although in most cases extrusion decrease in TDF a little. The thermo-mechanical treatment undergone by the buckwheat flour during extrusion led to redistribute part IDF fraction to SDF, leading to an increase in the latter. The content of rutin was increased about two fold in extruded flour of sprout, compared to in control. This increase maybe why these compounds are released from cell wall by high shear processing under high temperature.

• Journal of Environmental Health Sciences
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• v.15 no.1
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• pp.33-49
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• 1989

Pollution in the rivers has received considerable attention in recent years, particullary with reference to the effect due to increasing concentration of heavy metals. The metals are toxic to the ecosystem as a whole and to man in particular, since he is at the end of a variety of food chains by virture of his varigated diet. In addition, numerous laboratory tests have established that certain metals, such as Cd, pose a threat to a wide variety of aquatic organisms at concentrations as low as a few $\mu$g/1. Before the biological effects of heavy metals in impacted ecosystems can be completely assessed, however it is necessary to provide data on the concentration of heavy metals in such systems. This study was performed to investigate the concentration level of heavy metals in water, fish and sediments from upstream ($S_1-S_4$) to downstream ($S_5-S_9$) of the Mankyung river. Samples of water, fish, and sediments were collected along the tributaries of the Mankyung from September to October in 1987 and analyzed for lead, cadmium, copper, and zinc by atomic absorption spectrophotometer. From the data presented in this study, we can infer that the concentrations of the heavy metals investigated both in water and sediments are similar to those found in literature for unpolluted regions. The results obtained from the analysis of the edible tissue of the C. auratus show low concentration levels of the four heavy metals investigated. We conclude that the area is still relatively unpolluted and recommended continuing the monitoring of heavy metal concentrations to improve our understanding of their cycle in the river environment.

• Journal of the Korean Data and Information Science Society
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• v.17 no.3
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• pp.889-904
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• 2006

Our purpose is to ascertain, if possible, whether atomic bomb survivors with cataracts and epilation were more radiosensitive than those survivors with cataracts but without epilation. A major ophthalmologic survey was conducted in Hiroshima and Nagasaki in 1963-64. At that time, 2125 individuals were examined. Among these individuals, estimated eye organ doses, based on the DS86 dosimetry system, and information on the occurrence of epilation within the first 60 days following the bombings are available on 1742. In the analysis of these data we have assumed that each individual represents a sample of one from a binomial distribution, and that the occurrence of cataracts and epilation are independent biological phenomena. We got following results. The threshold for cataract induction and its 95% confidence limits have been estimated from data on the occurrence of cataract and epilation. Among the 1742 study subjects, 40 had both cataracts and severe epilation. The estimated threshold based on these cases is 0.98 sievert(Sv), with 95% lower and upper confidence bounds of 0.72, and 1.32 Sv, respectively, and is highly statistically significant. Among the 27 cases of cataracts where severe epilation was not reported, the estimated threshold is 1.74 Sv with 95% lower and upper confidence bounds of 1.21 Sv, and "not estimable". The difference between these two estimates is not statistically significant although the effect of dose is highly significant in both instances. The potential importance of biases in the DS86 dose estimates is discussed. The difference between the threshold estimated from cataract cases with epilation and that from cases without epilation is not statistically significant at the 5% or 10% level, and thus affords no support for the notion of increased radiosensitivity.