• Computers and Concrete
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• 제23권6호
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• pp.421-431
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• 2019

The alarming rate of depletion of natural stone based coarse aggregates is a cause of great concern. The coarse aggregates occupy nearly 60-70% by volume of concrete being produced. Research efforts are on to look for alternatives to stone based coarse aggregates from sustainability point of view. Response surface methodology (RSM) is adopted to study and address the effect of ferrochrome slag (FCS) replacement to coarse aggregate replacement in the ordinary Portland cement (OPC) based concretes. RSM involves three different factors (ground granulated blast furnace slag (GGBS) as binder, flyash (FA) as binder, and FCS as coarse aggregate), with three different levels (GGBS (0, 15, and 30%), FA (0, 15, and 30%) and FCS (0, 50, and 100%)). Experiments were carried out to measure the responses like, workability, density, and compressive strength of FCS based concretes. In order to optimize FCS replacement in the OPC based concretes, three different traditional optimization techniques were used (grey relational analysis (GRA), technique for order of preference by similarity (TOPSIS), and desirability function approach (DFA)). Traditional optimization techniques were accompanied with principal component analysis (PCA) to calculate the weightage of responses measured to arrive at the final ranking of replacement levels of GGBS, FA, and FCS in OPC based concretes. Hybrid combination of PCA-TOPSIS technique is found to be significant when compared to other techniques used. 30% GGBS and 50% FCS replacement in OPC based concrete was arrived at, to be optimal.

• Parasites, Hosts and Diseases
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• 제55권3호
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• pp.239-246
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• 2017

Strains of Toxoplasma gondii in Brazil are highly genetically diverse compared to strains from North America and Europe. Dogs are epidemiologically important because they act as sentinels for T. gondii infections in humans and are good indicators of environmental contamination. The aim of this study was to isolate and genetically characterize T. gondii strains from tissues of naturally infected Brazilian dogs. For this study, 21 blood samples were collected from dogs at the Zoonosis Control Centers of $Ilh{\acute{e}}us$ and Itabuna cities, Bahia, Brazil. The sera were examined for T. gondii antibodies using the indirect hemagglutination test. Brains and hearts of seropositive dogs were bioassayed in mice to isolate and characterize T. gondii parasites by PCR-RFLP using 10 genetic markers (SAG1, newSAG2, SAG3, BTUB, c22-8, c29-2, GRA6, PK1, APICO, and L358). However, T. gondii was isolated from only 4 (57.1%) dogs, designated TgDgBr6, 13, 17, and 21. All strains were virulent, causing clinical changes (rough hair coat, lethargy, and abdominal distention) and the death of all mice within 8-20 days after inoculation. Genetic analysis of these 4 T. gondii isolates revealed 4 distinct genotypes with different clonal lineage combinations (types I, II, and III) and 2 atypical alleles. Using PCR-RFLP with several markers, this study contributes to evaluations of the genetic diversity of strains circulating in Brazil.

• 한국수자원학회논문집
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• 제51권2호
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• pp.131-140
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• 2018

강우는 물순환 시스템을 이해를 증가 시킬 뿐만 아니라, 효율적인 수자원 확보 및 관리에 있어서 가장 핵심적인 인자이다. 본 연구는 2015년을 대상으로 한반도에서의 92개의 ASOS 지점자료와 최근에 발사된 GPM 위성강우 자료의 비교를 통하여 활용가능성을 평가하였다. 또한 지점 자료의 장점과 인공위성 자료의 장점을 융합함으로써 보다 개선된 강우자료를 산출하기 위해 3가지의 상세화 방법(Geographical Differential Analysis, Geographical Ratio Analysis, Conditional Merging)들을 적용하였다. 이 연구에서 도출된 결과는 다음과 같다. 1) ASOS 자료와의 검증을 통해 GPM 강우자료가 약간 과대산정되는 편향을 가지고 있는 것을 확인하였으며, 특히 여름 기간에 오차가 높게 발생하는 것으로 나타났다. 2) Jackknife 방법을 통하여 각 합성방법에 대해서 검증하였을 때, 공간해상도가 높아짐에 따라서 오차가 줄어드는 것을 확인하였으며, 상세화 방법 중 conditional merging 방법이 가장 좋은 성능을 나타내었다.

• 한국균학회지
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• 제47권4호
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• pp.291-301
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• 2019

선충 포식성곰팡이는 선충 포획 기관을 만들어 선충 포획 후 양분을 섭취하는 곰팡이다. 이들 중 Arthrobotrys flagrans와A. superba에 대한 특성들 중 보고될 때 생략된 것이 있어 두 종을 토양으로 부터 분리하고 순수배양하여 추가적으로 조사하였다. 선충 종류별 포식력, 포식기관의 형태·크기, 분생포자의 형태·크기, 분생포자병의 형태, 후막포자 등을 조사하였으며, ITS rDNA 염기서열의 분자계통학적 분석을 토대로 종 동정을 실시하였다. 또한 1981년 처음으로 선충 포식성곰팡이가 국내에서 보고된 이래로 현재까지 총 21종이 발견되었으나 이들에 대한 분류 체계와 주요 식별 형질이 없는 상황이었기에 제공하였다. 이를 바탕으로 아직 연구가 많이 진행되지 않은 국내 선충 포식성곰팡이 연구에 기초자료가 될 수 있기를 기대한다.

• Smart Structures and Systems
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• 제17권5호
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• pp.819-835
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• 2016

In this paper, the activities carried out within the EU funded Clean Sky Joint Technology Initiative (JTI GRA) Project and aimed at developing a morphing flap, are illustrated. The reference device is a regional aircraft single slotted flap, enhanced with deforming capabilities to obtain improved hyper-lift performance. The design started with the identification of the internal architecture, intended to allow camber variations. A concentrated-hinge architecture was selected, for its ability to fit different curvatures and for the possibility of easily realizing an "armadillo-like" configuration, then avoiding the use of a complicate deformable skin. The flap layout is made of segmented ribs, elastically hinged each other and span-wise connected by conventional spars. Relative rotations of the rib elements are forced by SMA structural actuators, i.e., cooperating in the external loads absorption. Super-elastic SMA are used to make up recovery elastic elements, necessary to regain the original shape after activation. These further elements in turn contribute to the overall flap rigidity. After assessing the hinge number and the size of the SMA active and passive elements, the advanced design phase was dealt with. It was aimed at solving manufacturing issues and producing the executive drawings. The realized demonstrator was finally tested in lab conditions to prove its functionality in terms of whether target shape actuation or attained shape preservation under loads. On the basis of the numerical results and the experimental outcomes, precious hints were obtained for further developments of the concept.

• 한국산학기술학회논문지
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• 제14권9호
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• pp.4492-4497
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• 2013

차세대 무선 네트워크 시스템에서 이동 단말은 다수의 무선 액세스 네트워크를 접속할 수 있는 능력을 갖는다. 이런 이기종 환경에서 네트워크 선택 메커니즘은 사용자에게 QoS를 보장해주기 위한 중요한 역할을 담당한다. 본 연구에서는 최적의 네트워크 선택을 위해 AHP 기법을 그룹결정방법에 적용한다. 특정 QoS를 요구하는 사용자들과 유사한 특성을 갖는 액세스 네트워크들을 각각 그룹으로 생각한다. 이 경우 비슷한 특성을 갖는 네트워크들을 그룹으로 묶어, 일차적으로 그룹간의 판별을 통해 적합한 그룹을 선택한 후, 그 그룹에서 네트워크 선택 알고리즘에 의한 네트워크 순위를 통해 최적의 네트워크를 선택해 주는 방법이다. 여기서 네트워크 선택 알고리즘은 결정요소의 가중치를 계산하는 AHP와 접근 네트워크의 등급을 결정하는 GRA 방법을 이용한다. MATLAB 시뮬레이션 결과, 제안된 시스템은 각 서비스 내 모든 사용자들이 0.9 이상의 높은 판정값으로 동일한 네트워크를 선택함을 알 수 있었다. 결과적으로 제안된 시스템은 WLAN과 UMTS의 통합망에서 기존시스템에 비해 효과적인 네트워크 선택 알고리즘임을 알 수 있다.

• Journal of Microbiology
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• 제35권3호
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• pp.165-171
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• 1997

A sulfer-oxidizing bacterium was isolated from mine wastewater and characterized. The isolate was gra-negative, rod (0.2 * 1.2-1.5.mu.m), nonmotiloe, catalase positive, and oxidase prositive. The opotimal pH and temperature for growth were 7.0 and 30.deg.C. respectively. The optimum thiosulfate concentration was 70 mM and the maximum growth rate was 0.081 hr. The major ubiquinone contained in the isolate was Q-8. The cellular fatty acid composition was $C_{16 : 0}$, $C_{18 : 1}$, $C_{17cyc}$,and $C_{19cyc}$ as nonpolar fatty acids, and 3-OH C10 : 0 and 3-OH $C_{12 : 0}$ as hydroxylated fatty acids. The isolate was a facultative chemolithoautotroph which can grow autotrophically on sodium thiosulfate and sodium sulfide and which can grow heterotrophically on yeast extract. It can also grow mixotrophically on sodium thiosulfate and yeast extract. Comparison of the 16S rRNA gene sequence of the isolate with that of Thiobacillus species and Paracoccus thiocyanatus revealed that it is closely related to T. caldus which belongs to the .betha.-subclass of the class Proteobacteria. However, the isolated could not grow at extremely low pH (pH 1-3.5). On the basis of the phenotypic, chemotaxonomic and phylogenetic data, the isolate was tentatively named Thiobacillus sp. strain C.ain C.

• 한국미생물·생명공학회지
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• 제42권1호
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• pp.1-10
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• 2014

식품발효용으로 사용하는 미생물은 오랜 기간의 사용이력에 근거하여 안전성에 대한 의문이 제기되지 않고 사용되어 왔다. 한편, 가공식품산업의 발달로 국제적인 식품 거래가 활발해지면서 수입국의 소비자와 정부당국은 식품에 첨가하는 미생물의 안전에 대해서 더욱 민감하게 반응하고 있다. 현재, 식품에 첨가하는 미생물에 대한 안전성 평가기준은 미국 Food and Drug Administration (FDA)가 사용하고 있는 Generally Recognized as Safe (GRAS)와 유럽연합 European Food Safety Agency (EFSA)의 Qualified Presumption of Safety (QPS)가 대표적으로 적용되고 있다. GRAS는 식품에 첨가하는 미생물 자체에 대한 안전성이 아닌 특정용도에서의 첨가에 따른 안전성을 의미하고, QPS는 식품에 첨가 가능한 미생물 단위(분류학적 단위, taxonomic unit)에 대한 안전성 평가이다. 우리나라에서는 전통발효식품의 상업적 생산이 증가하면서 종균 적용이 추진되고 있지만, 식품발효용종균에 대한 안전성 기준규격 없어 안전성 평가 없이 기능성만으로 종균 개발이 진행되고 있다. 전통발효식품의 세계화를 위해서는 향후 적용될 종균에 대한 기능적 측면뿐만 아니라 안전성의 확보가 필요하고, 식품용 미생물에 대한 안전성 평가 기준의 마련이 필요한 시점에 도달해 있다.

• Journal of Chest Surgery
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• 제25권6호
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• pp.650-660
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• 1992

To elucidate a potential contribution of endotheline-1[ET-1] to the genesis of pulmonary hypertension and postoperative pulmonary hypertensive crisis in the patients with heart disease, we measured plasma levels of the ET-1 during perioperative period of open heart surgery. In addition, we examined changes of ET-1 during perioperative period and correlations between ET-1 levels and hemodynamic variables. 12 patients including 5 acquired heart disease and 7 congenital heart disease patients were selected randomly as a study group, Group A and B, respectively. 6 patients proved not having heart or hemodynamic problem were selected as a control, Group C. 110 blood samples from pulmonary artery[ET-P] and radial artery[ET-S] were taken and assayed by Sep-pak extraction and RIA. ET-1 levels of Group A were ET-P, 3.94$\pm$5.31pg /ml, ET-S, 3.10$\pm$2.90pg/ml[p>0.05], Group B were ET-P, 1.63$\pm$0.62pg/ml, ET-S, 1.99$\pm$2.45pg/ml[p>0.05], Group C were ET-P, 1.97$\pm$2.02pg/ml, ET-S, 1.72$\pm$0.77pg/ml[p>0.05]. There were no statistically significant differences of ET-1 levels among the Group A, B, C[p>0.05]. There was no correlation between pulmonary artery pressure[PAP] and ET-1 level[p>0.05], and ET-1 levels were not increased even in the cases of pulmonary hypertensive criwis or low cardiac output syndrome, whereas significant correlation between ET-S and pulmonary vascular res-istance[Rp] [r=0.36, p<0.05], and negative correlation between ET-S and OS saturation of pulmonary artery[OS-P][r= -0.49, p<0.01] were identified. Another significant finding was peak increase of ET-1 levels in the postoperative period 1 hour[p<0.05] and then gra-dualy decrease through the postoperative period. In conclusion, ET-1 has no correlation with PAP, whereas correlation with Rp, and inverse correlation with OS-P. It is suggested that ET-1 is neither the direct causative substance of pulmonary hypertension nor pulmonary vasospasm but there must be increased production of ET-1 in chronic pulmonary hypertensive state. Counter-regulatory mechanism to ET-1 is speculated during the pulmonary vasospasm.

• Parasites, Hosts and Diseases
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• 제51권3호
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• pp.363-367
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• 2013

The prevalence of Toxoplasma gondii infection in birds has epidemiological significance because birds are indeed considered as a good indicator of environmental contamination by T. gondii oocysts. In this study, the prevalence of T. gondii in 313 house sparrows in Lanzhou, northwestern China was assayed by the modified agglutination test (MAT). Antibodies to T. gondii were positive in 39 (12.46%) of 313 samples (MAT titer ${\geq}$ 1:5). Tissues of heart, brain, and lung from the 39 seropositive house sparrows were tested for T. gondii DNA, 11 of which were found to be positive for the T. gondii B1 gene by PCR amplification. These positive DNA samples were typed at 9 genetic markers, including 8 nuclear loci, i.e., SAG1, 5'- and 3'-SAG2, alternative SAG2, SAG3, GRA6, L358, PK1, c22-8 and an apicoplast locus Apico. Of them, 4 isolates were genotyped with complete data for all loci, and 2 genotypes (Type II variants; ToxoDB #3 and a new genotype) were identified. These results showed that there is a potential risk for human infection with T. gondii in this region. To our knowledge, this is the first report of T. gondii seroprevalence in house sparrows in China.