• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.198-201
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• 2015

The prompt and accurate location determination of the nodes of the wireless indoor shipboard networks is crucial to forming the stable wireless shipboard sensor networks. To this end in this paper it can be achieved through the measurement of the bi-directional channel qualities among the nodes after the locations of the sensor nodes temporarily placed. For the 1st stage the piconet-type sensor networks are considered to measure the channel qualities between a specific node and the cluster node which is the master node. After finishing the 1st stage measurement the nodes needing the relay nodes are selected and the measurement action goes into the 2nd stage. In the 2nd stage the measurement between a candidate relay node and the node needing a relay node starts to begin. After the 2nd stage the relay nodes to connect to the cluster node are fixed and the information delivery paths between a node and the cluster head are established. In this paper the measurement results in the realistic environment are gathered and analysed to show that the measurement procedure can be applied in the wireless indoor shipboard networks.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.87-87
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• 2000

이온빔 증착에 있어서 전자의 조사가 이온빔 증착기구에 미치는 영향에 대한 연구는 지금까지 보고 되어지지 않았다. 특히 전자의 조사가 증착층의 물성에 영향을 미칠 수 있느지에 대하여 정량적인 결과를 실험을 통하여 제시한 보고는 내가 아는 한 존재하지 않는다. 한편 이와같이 박막 증착에 있어서 전하가 증착되어지는 박막의 물성에 미칠 수 있는 영향에 대해서는 많은 과학자들의 관심사이기도 하다. 본 실험에서는 kaufman ion gun을 이용하여 질소 양이온을, 그리고 Cs+ ion gun을 이용하여 탄소 음이온을 조사하고 이들을 이용하여 CN 박막을 증착하였다. 질소 양이온의 에너지는 100eV, 이온밀도는 70$\mu$A/$\textrm{cm}^2$로 고정하고, 탄소 이온빔(80$\mu$A/$\textrm{cm}^2$)의 에너지를 200cV까지 변화시켜가며 증착하였다. 이때 증착층의 특성에 음 전하의 효과를 유발하기 위하여 350~360$\mu$A/$\textrm{cm}^2$의 전자빔을 이온빔 증착과 동시에 추가로 조사하였고 이의 특성을 전자빔을 조사하지 않고 증착한 CN 박막의 특성과 서로 비교하였다. 또한 증착 표면의 전하 축적에 의한 입사 이온빔의 에너지 감소에 의한 영향을 방지하기 위하여 증착되는 Si 기판에 HF (300kHz, 3.5V) bias를 가하여 주었다. 전자빔의 조사와 동시에 이루어진 CN 박막의 증착은 입사하는 탄소 음 이온빔의 에너지가 80eV에서 180eV 사이일때 원자밀도의 향상과 질소함량의 증가, 그리고 sp2C-N 결합대비 sp3C-N 결합의 향상이 이루어졌음을 확인하였다. 이는 이온빔 충돌에 의하여 피코쵸 정도의 시간대에 이루어지는 박막내의 collision cascade 영역에 이에 의하여 생긴 결함부위에 유입된 음 전하가 위치하면 전하주위의 원자와 polarization을 형성하고 이에 의하여 탄소와 질소의 결합을 형성하는데 필요한 자유에너지의 감소를 수반하는 방향으로 원자의 배열이 이루어지기 때문으로 사료된다. 이와같이 이온빔 에너지가 이온빔 증착 기구의 주요한 인자로 널리 인식되고 있는 kinetic bonding process에 있어서 이온 에너지에 의하여 activation energy barrier를 넘은후, 전자의 조사가 자유에너지를 낮추는 방향으로 최종 결합경로를 조절할 수 있기 때문에 이온빔 증착을 조절할 수 있는 또 하나의 주요한 인자로 받아들여질 수 있으리라 판단된다. 이온빔 프로세스에 의한 DLC 혹은 탄소관련 필름을 형성하는데 있어서 입사 이온빔의 에너지에 의하여 수반되는 thermal spike 혹은 외부 열원에 의한 가열은 박막층의 흑연화를 수반하기 때문에 박막의 sp3 특성을 향상시키기 위하여 회피하여야 할 요소이지만 thermal spike에 의한 국부 영역의 가열과 같은 불가피한 인자가 존재하는 상황에서 전자에 의한 추가 전하의 조사에 의한 최종결합경로의 선택적 조절은 박막의 화학적 결합과 물리적 특성을 향상시킬 수 있는 중요한 방법이 될 수 있다고 판단된다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.225-231
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• 2008

It is known that Spirulina extracts have strong antioxidant activities since it contains diverse antioxidants such as phycocyanian, ${\beta}$-carotene, vitamin E and other carotenoids. In order to enhance antioxidant activity of Spirulina, Spirulina extracts were fermented by Lactobacillus plantarum P23 and Bacillus subtilis TP6. The resulting fermented supernatants were analyzed for their antioxidant activities by DPPH (1,1-diphenyl-2-picrylhydiazyl) method. The results indicated that fermentation process significantly enhanced total antioxidant activities. Increased levels of UV-induced TNF-${\alpha}$ and IL-6 were reduced back to normal level even by treatment of all three of the Spirulina extracts. The result suggested that the fermentation process enhanced the anti-inflammatory activities at least ten times higher than the simple extract. Zymography is used to determine the expression of UV-induced MMP. Spirulina extracts fermented by Bacillus subtilis TP6 were found to suppressed the expression of MMPs. Also treatment with the fermented Spirulina extracts resulted in an increase of collagen synthesis in vitro. In conclusion, the fermented Spirulina extracts are expected to be used as anti-aging cosmeceuticals.

• Polymer(Korea)
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• v.38 no.1
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• pp.43-48
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• 2014

In this paper, we made a new polycationic polymeric liposome composed of low molecular weight polyethylenimine (PEI) and 10,12-pentacosadiynoic acid (PCDA). PCDA liposome was prepared by ultraviolet irradiation. PEI was further conjugated on the surface of the polymerized PCDA liposome using coupling reagents to make PCDA-PEI. The blue-to-red transition of PCDA liposome was observed during the coupling reaction. The size distribution of liposome and complexes with plasmid DNA was measured by dynamic light scattering (DLS). The complex formation was also identified by agarose gel electrophoresis and PicoGreen reagent assay. We confirmed the complex formation of the polymeric liposome with DNA and then performed transfection and cytotoxicity assay in HEK 293 and HeLa cells. As a result, PCDA-PEI showed significant gene transfection efficiency and low cytotoxicity. This study shows that PEI-conjugated PCDA liposome could be an efficient gene or drug delivery carrier.

• Journal of Korea Water Resources Association
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• v.56 no.6
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• pp.373-380
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• 2023

Due to abnormal climate phenomena and climate change in Korea, overgrowth of algae in rivers and reservoirs occurs frequently. Algae in rivers are classified into green algae, blue-green algae, diatom, and other types, and some species of blue-green algae cause problems due to odor and the discharge of toxic substances. In Korea, an algae alert system is in place, and it is issued based on the number of harmful blue-green algae cells. Thus, measuring harmful blue-green algal blooms is very important, and currently, the analysis method of algae involves taking field samples and determining the cell count of green algae, blue-green algae, and diatoms through algal microscopy, which takes a lot of time. Recently, the analysis of algae concentration through Phycocyanin, an alternative indicator for the number of harmful algae cells, has been conducted through remote sensing. However, research on the analysis of the number of blue-green algae cells is currently insufficient. In this study, we water samples for algal analyses were collected from river and counted the number of blue-green algae cells using algae microscopy. We also obtained the Phycocyanin concentration using an optical sensor and acquired algae spectra through a hyperspectral sensor. Based on this, we calculated the equation for estimating blue-green algae cell counts and estimated the number of blue-green algae cells.

• Journal of Life Science
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• v.26 no.4
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• pp.460-467
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• 2016

A filamentous cyanobacterium, Limnothrix sp. KNUA012, was axenically isolated from a freshwater bloom sample in Lake Hapcheon, Hapcheon-gun, Gyeongsangnam-do, Korea. Its morphological and molecular characteristics led to identification of the isolate as a member of the genus Limnothrix. Maximal growth was attained when the culture was incubated at 25℃. Analysis of its lipid composition revealed that strain KNUA012 could autotrophically synthesize alkanes, such as pentadecane (C₁₅H₃₂) and heptadecane (C₁₇H₃₆), which can be directly used as fuel without requiring a transesterification step. Two genes involved in alkane biosynthesis－an acyl-acyl carrier protein reductase and an aldehyde decarbonylase－were present in this cyanobacterium. Some common algal biodiesel constituents－myristoleic acid (C_14:1), palmitic acid (C_16:0), and palmitoleic acid (C_16:1)－were produced by strain KNUA012 as its major fatty acids. A proximate analysis showed that the volatile matter content was 86.0% and an ultimate analysis indicated that the higher heating value was 19.8 MJ kg⁻¹. The isolate also autotrophically produced 21.4 mg g⁻¹ phycocyanin－a high-value antioxidant compound. Therefore, Limnothrix sp. KNUA012 appears to show promise for application in cost-effective production of microalga-based biofuels and biomass feedstock over crop plants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1515-1520
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• 2012

This study evaluate the quality characteristics and antioxidative properties of acorn starch mook containing spirulina (0%, 0.5%, 1%, 1.5%) and soy protein (3%). The pH of acorn starch mook containing the spirulina and soy protein decreased with increasing amount of spirulina decrease in pH means an increase in acidity. In addition, the moisture content was 87%. The lightness of acorn starch mook containing spirulina and soy protein decreased with increasing amount of spirulina and soy protein. The L and a values of the Hunter color system were decreased significantly increasing spirulina content, and the b value increased. In contrast, with increasing spirulina and soy protein content, the L and a increased significantly and the b value. Texture analysis revealed higher hardness and springiness of acorn starch mook containing spirulina than the control. The total phenol content was highest in the acorn starch mook containing 1.5% spirulina and 3% soy protein. The antioxidant activities of the acorn starch mook containing spirulina and soy protein increased with increasing amount of spirulina and soy protein. The $IC_{50}$ value of 1.5% spirulina and 3% soy protein was 166.2 mg/mL for DPPH. The results of the sensory test were best in the acorn starch mook containing 1% spirulina.

• Asian Journal of Turfgrass Science
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• v.20 no.1
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• pp.65-76
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• 2006

Scz1, an isolate of Sclerotinia homoeocarpa, was recently reported as a novel pathogen responsible for dollar spot disease in Zoysiagrass, a warm season turfgrass. Scz1 possessed different characteristics on mycelial pigment, mycelial affinity and host pathogenecity compared to those of Scb1, a typical isolate, obtained from creeping bentgrass, a cool season turfgrass. In this study, only three isolates, Scz1, Scz2(another analogous isolate of Sclerotinia homoeocarpa from zoysiagrass), and Scb1, were examined at the molecular level using the internal transcribed spacer(ITS) and random amplified polymorphic DNA(RAPD) assays to verify their identification and genetic variation. As a result of ITS assay, partial ITS sequences of three isolates showed 94-97% similarity with a standardized ITS sequence of S. homoeocarpa registered on BLAST. In the analysis of RAPD, range value through similarity matrix was 0.167 between Scz1 and Scb1, 0.139 between Scz2 and Scb1, and 0.713 between Scz1 and Scz2, respectively. Furthermore, tendegram analysis indicated that Scz1 and Scz2, unlike Scb1, were clustered together as accompanying a high genetic similarity. In in vitro fungicide bioassay, $EC_{50}$ value representing the sensitivity degree to propiconazole, a well-known fungicide for dollar spot disease, was 0.012 ${\mu}g/ml$ for Sczl, 0.003 ${\mu}g/ml$ for Scz2, and 0.030 ${\mu}g/ml$ for Scb1. From all data taken, we concluded that both Scz1 and Scz2 belonged to one group of S. homoeocarpa, since they exhibit the same host range and high level of genetic similarity, whereas their chemical competences to a fungicide were different. This study would provide further approach for assessing genetic diversity of S. homoeocarpa isolates as well as characterizing individual isolate against chemical exposure.

• Journal of the Korean Applied Science and Technology
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• v.35 no.2
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• pp.423-432
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• 2018

Arthrospira platensis is one of the oldest algae in the world and has been reported to have anti-aging properties, including phycocyanin, tocopherol and beta-carotene. In this study, we tried to search protective activities against UVB-induced reactive oxygen species(ROS) of Arthrospira platensis under indoor cultivation ethanol extracts(ICAE) and outdoor cultivation ethanol extracts(OCAE). The anti-oxidative capacities were evaluated by DPPH radical scavenging activity and SOD-like activities at various concentrations(0.1, 0.5, $1mg/m{\ell}$) of ICAE and OCAE. Zebrafish embryos and HaCaT cells were exposed to UVB radiation and treated with various concentrations(0, 0.01, 0.05, 0.1, 0.5, $1mg/m{\ell}$) of ICAE and OCAE. ROS levels of zebrafish and HaCaT cells were generated by UVB radiation. ROS levels were detected using a fluorescent microscope after DCFH-DA staining. The DPPH radical scavenging activity of ascorbic acid was 73% and SOD-like activity was 86% in the positive control group. ICAE and OCAE at $1mg/m{\ell}$ concentration showed 43, 57% DPPH radical scavenging activity and 20, 19% SOD-like activity. Anti-oxidative of ICAE and OCAE had lower effects than the positive control ascorbic acid but significant results. ROS of UVB-induced zebrafish embryos and HaCaT cells were higher than negative control. ICAE and OCAE treated group decreased ROS concentration dependently than UVB-induced positive control group. These results suggest that Arthrospira platensis ethanol extract may have usability value as a cosmetic material for skin protection.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.161-170
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• 2008

Recently irregular dark-colored patches were found on the Kentucky teeing ground in a golf course in Gyunggi providence. Interestingly, blue-green algae from the leaf tissue sample containing black spot-stained symptoms were largely observed through microscopic study. In general, algae present on the upper soil surface or in the upper layer of root zone form dark brown layers of scum or crust, which invoked harmful effects to turf growth such as poor drainage, inhibition of new root development. In this observation, unlike the algae were sometime found in senescing leaves on contacted soil in July and August, the blue-green algae were detected within black spot-stained Kentucky bluegrass leaf tissues including leaf blade, ligule, auriclea as well as leaf sheath. The blue-green algae were also detected on the leaf and stem tissue adjacent to the symptomatic leaf tissues. Two species of blue-green algae, Phomidium and Oscillatoria, were greatly observed. Oscillatoria species was more commonly notified in all samples. In addition, the two species were found on a putting green showing yellow spot disease at another golf course in Gyunggi providence. The data from chemical control assay revealed that chemicals such as propiconazole, iprodione, and azoxystrobin decreased blue-green algae population and leaf spots, which finally resulted in enhanced leaf quality. All taken together, we strongly suggested that the disease-like phenomenon by blue-green algae might be very closely mediated with infection/translocation process in relation with turfgrass. It indicates that blue-green algae in turf management may play an adverse role as a secondary barrier as well as a pathogenic agent. This report may be helpful for superintendents to recognize and understand the fact that algae control should be provided more cautiously and seriously than we did previously in upcoming golf course management.