• The Korean Journal of Physiology and Pharmacology
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• 제17권6호
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• pp.485-491
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• 2013

The present study was designed to investigate the putative effect of neurosteroid modulation on global ischaemia-reperfusion-induced cerebral injury in mice. Bilateral carotid artery occlusion followed by reperfusion, produced a significant rise in cerebral infarct size along with impairment of grip strength and motor coordination in Swiss albino mice. Administration of carbamazepine (16 mg/kg, i.p.) before global cerebral ischaemia significantly attenuated cerebral infarct size and improved the motor performance. However, administration of indomethacin (100 mg/kg, i.p.) attenuated the neuroprotective effect of carbamazepine. Mexiletine (50 mg/kg, i.p.) did not produce significant neuroprotective effect. It may be concluded that the neuroprotective effect of carbamazepine may be due to increase in synthesis of neurosteroids perhaps by activating enzyme ($3{\alpha}$ HSD) as indomethacin attenuated the neuroprotective effect of carbamazepine. The sodium channel blocking effect of carbamazepine may not be involved in neuroprotection as mexiletine, a sodium channel blocker, did not produce significant neuroprotective effect.

• Journal of Forest and Environmental Science
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• 제25권2호
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• pp.101-109
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• 2009

The Hajong are the ancient tribal forest community among the ethnic minorities of the North-East region of Bangladesh. The study was carried out with respect to three income groups highlighting their indigenous knowledge. A total of forty-five households (fifteen from each income groups) were assessed using different participatory appraisals through semi-structured questionnaires. A special type of indigenous knowledge on food habit was explored in the Hajong community, which correspond to the severe dependence on forest resources. They collect their food resources from homestead forest (45%) followed by forest (40%), market and others. They have indigenous hunting procedure to trap the animal in the forest. Twenty three tree species were tremendously planted in their homestead forests which are the very important source of food. Male are highly responsible to collect the food materials from forest as well as other sources.

• Carbon letters
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• 제26권
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• pp.88-94
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• 2018

This manuscript explains the effective determination of urea by redox cyclic voltammetric analysis, for which a modified polypyrrole-graphene oxide (PPY-GO, GO 20% w/w of PPY) nanocomposite electrode was developed. Cyclic voltammetry measurements revealed an effective electron transfer in 0.1 M KOH electrolytic solution in the potential window range of 0 to 0.6 V. This PPY-GO modified electrode exhibited a moderate electrocatalytic effect towards urea oxidation, thereby allowing its determination in an electrolytic solution. The linear dependence of the current vs. urea concentration was reached using square-wave voltammetry in the concentration range of urea between 0.5 to $3.0{\mu}M$ with a relatively low limit of detection of $0.27{\mu}M$. The scanning electron microscopy was used to characterize the morphologies and properties of the nanocomposite layer, along with Fourier transform infrared spectroscopy. The results indicated that the nanocomposite film modified electrode exhibited a synergistic effect, including high conductivity, a fast electron-transfer rate, and an inherent catalytic ability.

• BMB Reports
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• 제40권2호
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• pp.261-269
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• 2007

The structure and dynamics of a 37-residue antimicrobial peptide gaegurin 4 (GGN4) isolated from the skin of the native Korean frog, Rana rugosa, was determined in SDS micelles by NMR spectroscopy. The solution structure of the peptide in SDS micelles was determined from 352 NOE-derived distance constraints and 22 backbone torsion angle constraints. Dynamic properties for the amide backbone were characterized by $^1H-^{15}N $heteronuclear NOE experiments. The structural study revealed two amphipathic helices spanning residues 2-10 and 16-32 and that the helices were connected by a flexible loop. An intraresidue disulfide bridge was formed between residues Cys31 and Cys37 near the C-terminus. The loop region (11-15) connecting the two helices are were slightly more flexible than these helices themselves. From the fact that since there is no contact NOEs between two helices, it is implied that the GGN4 peptide shows an independent motion of both helices which has an angle of about $ 60^{\circ}-120^{\circ}$ from each other.

• 환경생물
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• 제30권3호
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• pp.157-163
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• 2012

Oxidative stress has been reported to be one of causes of neuritis. This study examined antioxidative activities of methanol extracts of six amphibian species known to be medicinal animals (Rana catesbeiana, R. coreana, R. rugosa, R. dybowskii, R. nigromaculata, and Hyla japonica) and investigated their effects of inhibiting nitric oxide (NO) production and cytotoxicity on the murine macrophage RAW264.7 cells. As inflammation is closely associated with reactive oxygen species, assays on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, xanthine oxidase inhibitory activity, superoxide anion radical scavenging activity and NO scavenging activity of the extracts of the six species were performed to investigate their antioxidative activity. The results obtained were as follows; All extracts showed antioxidative activity, and the activity of R. dybowskii was the highest in comparison among those. Anti-inflammatory effects of the extracts were also examined, the five extracts except that of R. rugosa did not show cytotoxicity for RAW264.7 cells at the maximal concentration ($1,000{\mu}g\;mL^{-1}$). Selectivity index, meaning NO scavenging activity compared to cytotoxicity, showed the highest level in the extract of R. dybowskii. These results will be very useful basic data for future studies on prevention and treatment of human diseases to understand the biological roles of amphibian extracts throughout the antioxidative or anti-inflammatory pathways.

• Journal of Ecology and Environment
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• 제33권3호
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• pp.229-236
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• 2010

We conducted field surveys of amphibians and reptiles over a two-year period in 16 lagoons along the eastern coastline of South Korea, and determined the habitat characteristics correlated with the number of amphibian and reptilian species and individuals. We documented 11 amphibian species and 8 reptilian species. The dominant amphibian species was the black-spotted pond frog (Rana nigromaculata), and the dominant reptilian species was the red-eared turtle (Trachemys scripta elegans), an invasive species. Among the 14 habitat characteristics, connectivity to mountainous area significantly affected the number of amphibian and reptilian individuals. Other factors, including emerged plant cover, salinity, pH, the number of birds for amphibians and connectivity to agricultural land, lagoon perimeter length for reptiles also influenced the number of species or individuals of them. Our results demonstrate that these lagoons are home to more amphibians and reptiles than has been previously known. To effectively conserve herpetofauna in the lagoon ecosystem, lagoons as well as surrounding wetlands, grasslands, and mountainous areas should be protected.

• Journal of Power Electronics
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• 제18권2호
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• pp.588-603
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• 2018

This paper presents the idea of a smart load that can adjust the input power flow based on the intermittent power available from RESs (Renewable Energy Resources) to regulate the line voltage, and draw a constant power from the grid. To this effect, an innovative power flow controller is presented based on a Resistive ES (Electric Spring) in combination with a PEAT (Power Electronics based Adjustable Transformer), which can effectively shape the load power flow at the subnetwork level. With a PEAT incorporated in the step down transformer at the grid side, the proposed controller can supply non-critical loads through local RESs, and the critical loads can draw a relatively constant power from the grid. If there is an abundance of power produced by the RESs, the controller can supply both non-critical loads and critical loads through the RES, which significantly reduces the power demand from the grid. The principle, practicality, stability analysis, and controller design are presented. In addition, simulation results show that the power flow controller performs well in shaping the load power flow at the subnetwork level, which decreases the power demand on the grid. Experimental results are also provided to show that the controller can be realized.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.237-240
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• 2003

This paper reports the characteristics of TFTs, formed inside a location-controlled grain: "single-crystalline" Si TFTs (c-Si TFTs). Position of the grains were controlled with a great precision by "${\mu}-Czochralski$ (grain-filter) process". Effects of process parameters, such as, deposition method of gate $SiO_2$, crystallization energy density and position of the channel with respect to the grain filters on TFT characteristics is investigated. It is concluded that the characteristics of TFTs drastically improved by avoiding the grain filter from the channel region. With TFTs having the current-flow direction parallel to radial direction from the grain-filter, electron mobility and subthreshold swing of 600 $cm^2/Vs$ and 0.21 V/dec. respectively are obtained.

• BMB Reports
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• 제32권1호
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• pp.12-19
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• 1999

Gaegurin 4 (GGN4), a broad-spectrum antibiotic, is a 37-amino acid peptide isolated from the Korean frog, Rana rugosa. In this study, we have chemically synthesized and purified GGN4 analogues where the C-terminal portion is truncated and/or substituted with tryptophan. These peptides show significantly different biological activities depending on the location of tryptophan and the number of amino acids truncated from the C-terminal end. While deletion of 9 amino acids from the C-terminal seems to be marginally tolerable in maintaining the antimicrobial activity, further deletion of up to 14 amino acid residues decreases the potency by more than 60-fold towards Gram-positive, and 10-fold towards Gram-negative, bacteria. Surprisingly, the reduced activity of the shorter peptide can be completely restored by a single substitution of aspartic acid 16 to tryptophan 16 (D16W). Also, the truncation seems to decrease the specificity of antibiotic activity more towards Gram-positive than towards Gram-negative bacteria studied. These data suggest a partial role of the C-terminal region in determining the binding specificity and the activity of peptides upon binding to their target cell membranes.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6925-6928
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• 2013

Background: Despite numerous useful anticancer properties of curcumin, its utility is limited due to its hydrophobic structure. In this study, we investigated the comparative antiproliferative effect of PAMAM encapsulating curcumin with naked curcumin on the T47D breast cancer cell line. Materials and Methods: Cytotoxic effects of PAMAM dendrimers encapsulating curcumin and curcumin alone were investigated by MTT assay. After treating cells with different concentrations of both curcumin alone and curcumin encapsulated for 24h, telomerase activity was determined by TRAP assay. Results: While PAMAM dendrimers encapsulating curcumin had no cytotoxicity on cancer cells, they decreased the $IC_{50}$ for proliferation and also increased the inhibitory effect on telomerase activity. Conclusions: Considering the non-toxicity in addition to effectiveness for enhancing curcumin anticancer properties, dendrimers could be considered good therapeutic vehicles for this hydrophobic agent.