• Structural Engineering and Mechanics
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• v.56 no.6
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• pp.959-982
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• 2015

In this study, a non-stationary random earthquake Clough-Penzien model is used to describe earthquake ground motion. Using stochastic direct integration in combination with an equivalent linear method, a solution is established to describe the non-stationary response of lead-rubber bearing (LRB) system to a stochastic earthquake. Two parameters are used to develop an optimization method for bearing design: the post-yielding stiffness and the normalized yield strength of the isolation bearing. Using the minimization of the maximum energy response level of the upper structure subjected to an earthquake as an objective function, and with the constraints that the bearing failure probability is no more than 5% and the second shape factor of the bearing is less than 5, a calculation method for the two optimal design parameters is presented. In this optimization process, the radial basis function (RBF) response surface was applied, instead of the implicit objective function and constraints, and a sequential quadratic programming (SQP) algorithm was used to solve the optimization problems. By considering the uncertainties of the structural parameters and seismic ground motion input parameters for the optimization of the bearing design, convex set models (such as the interval model and ellipsoidal model) are used to describe the uncertainty parameters. Subsequently, the optimal bearing design parameters were expanded at their median values into first-order Taylor series expansions, and then, the Lagrange multipliers method was used to determine the upper and lower boundaries of the parameters. Moreover, using a calculation example, the impacts of site soil parameters, such as input peak ground acceleration, bearing diameter and rubber shore hardness on the optimization parameters, are investigated.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.111-117
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• 1997

Streptomyces virginiae produces a set of autoregulators termed virginiae butanolide A-E(VB-A-E) which trigger virginiamycin production, and possesses a high-affinity virginiae butanolide receptor. To elucidate the functions of VB-C and VB-C receptor, we isolated two mutants from S. virginiae by N-methyl-N'-nitro-N-nitrosoguanidine and hydroxylamine. The characteristics of the mutants showed that the producing time of antibiotics was very delayed due to a slower production of VB-C receptor than that of VB. In S. ostreogriseus(VB', receptor -) and S. graminofaciens(VBU, receptor+), which produce the virginiamycin, the addition of synthetic VB-C repressed the production of antibiotics in S. ostreogriseus but induced tbe production in S. graminofaciens. HPLC analysis of S. graminofaciens suggested that the VB-C might have an ability to induce the production of virginiamycin and other antibiotics. These results imply that the VB-C has an ability to trigger the production of other secondary metabolites as well as virginiamycin under VB-C receptor existence.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.29-35
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• 2013

A Nodulisporium sp. (Hypoxylon sp.) has been isolated as an endophyte of Thelypteris angustifolia (Broadleaf Leaf Maiden Fern) in a rainforest region of Central America. It has been identified both on the basis of its morphological characteristics and by scanning electron microscopy as well as ITS sequence analysis. The endophyte produces volatile organic compounds (VOCs) that have both fuel (mycodiesel) and use for biological control of plant disease. When grown on potato dextrose agar, the organism uniquely produces a series of ketones, including acetone; 2-pentanone; 3-hexanone, 4-methyl; 3-hexanone, 2,4-dimethyl; 2-hexanone, 4-methyl, and 5-hepten, 2-one and these account for about 25% of the total VOCs. The most abundant identified VOC was 1,8 cineole, which is commonly detected in this group of organisms. Other prominent VOCs produced by this endophyte include 1-butanol, 2-methyl, and phenylethanol alcohol. Moreover, of interest was the presence of cyclohexane, propyl, which is a common ingredient of diesel fuel. Furthermore, the VOCs of this isolate of Nodulisporium sp. were selectively active against a number of plant pathogens, and upon a 24 h exposure caused death to Phytophthora palmivora, Rhizoctonia solani, and Sclerotinia sclerotiorum and 100% inhibition to Phytophthora cinnamomi with only slight to no inhibition of the other pathogens that were tested. From this work, it is becoming increasingly apparent that each isolate of this endophytic Nodulisporium spp., including the Daldina sp. and Hypoxylon spp. teleomorphs, seems to produce its own unique set of VOCs.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.361-368
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• 2005

A Korean isolate of Pepper mild mottle virus (PMMoV-Kr) was isolated from a diseased hot pepper plant and its biological and molecular properties were compared to that of PMMoV-J and PMMo V -So The genomic RNA of PMMoV-Kr consists of 6,356 nucleotides. The nucleotide and amino acid sequences identities of four viral proteins and two noncoding regions among PMMoV-Kr, PMMoV-S and PMMoV-J were $96.9\%\;to\;100.0\%\;and\;97.5\%\;to\;98.6\%$, respectively. Full-length cDNA amplicon of PMMoV-Kr was directly amplified by RT-PCR with a set of 5'-end primer anchoring T7 RNA promoter sequence and 3'-end virus-specific primer. Capped transcript RNAs from the full-length cDNA clone were highly infectious and caused characteristic symptoms of wild type PMMoV when mechanically inoculated to systemic host plants such as Nicotiana benthamiana and pepper plants.

• Journal of Preventive Medicine and Public Health
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• v.39 no.1
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• pp.13-20
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• 2006

Objectives: To propose a risk-adjustment model with using insurance claims data and to analyze whether or not the outcomes of non-emergent and isolated coronary artery bypass graft surgery (CABG) differed between the low- and high-volume hospitals for the patients who are at different levels of surgical risk. Methods: This is a cross-sectional study that used the 2002 data of the national health insurance claims. The study data set included the patient level data as well as all the ICD-10 diagnosis and procedure codes that were recorded in the claims. The patient's biological, admission and comorbidity information were used in the risk-adjustment model. The risk factors were adjusted with the logistic regression model. The subjects were classified into five groups based on the predicted surgical risk: minimal (<0.5%), low (0.5% to 2%), moderate (2% to 5%), high (5% to 20%), and severe (=20%). The differences between the low- and high-volume hospitals were assessed in each of the five risk groups. Results: The final risk-adjustment model consisted of ten risk factors and these factors were found to have statistically significant effects on patient mortality. The C-statistic (0.83) and Hosmer-Lemeshow test ($x^2=6.92$, p=0.55) showed that the model's performance was good. A total of 30 low-volume hospitals (971 patients) and 4 high-volume hospitals (1,087 patients) were identified. Significant differences for the in-hospital mortality were found between the low- and high-volume hospitals for the high (21.6% vs. 7.2%, p=0.00) and severe (44.4% vs. 11.8%, p=0.00) risk patient groups. Conclusions: Good model performance showed that insurance claims data can be used for comparing hospital mortality after adjusting for the patients' risk. Negative correlation was existed between surgery volume and in-hospital mortality. However, only patients in high and severe risk groups had such a relationship.

• Journal of Biomedical Engineering Research
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• v.40 no.5
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• pp.143-150
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• 2019

To evaluate the toxicity of ophthalmic drug, the Draize test and Bovine Corneal Opacity and Permeability (BCOP) test commonly used. In Draize test, experimental animals were under stress and pain due to long-term exposure of drug. In addition, regarding physiological functions, animal model is not perfectly reflected a human eye condition. Although some models such as $EpiOcular^{TM}$, HCE model, LabCyte Cornea-Model, and MCTT $HCE^{TM}$ were already presented advanced cornea ex-vivo model to replace animal test. In this sense, cornea tissue structure mimicked ex-vivo toxicity model was fabricated in this study. The corneal epithelial cells (CECs) and keratocytes (CKs) isolated from rabbit eyeball were seeded on non-patterned silk film (n-pSF) and patterned silk film (pSF) at $32,500cells/cm^2$ and $6,500cells/cm^2$. Sequentially, n-pSF and pSF were stacked to mimic a multi-layered stroma structure. The thickness of films was about $15.63{\mu}m$ and the distance of patterns was about $3{\mu}m$. H&E stain was performed to confirm the cell proliferation on silk film. F-actin of CKs was also stained with Phalloidin to observe the cytoskeletal alignment along with patterns of the pSF. In the results, CECs and CKs were shown the good cell attachment on the n-pSF and pSFs. Proliferated cells expressed the specific phenotype of cornea epithelium and stroma. In conclusion, we successfully established the ex-vivo cornea toxicity model to replace the eye irritation tests. In further study, we will set up the human ex-vivo cornea toxicity model and then will evaluate the drug screening efficacy.

• Plant Resources
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• v.4 no.1
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• pp.41-47
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• 2001

This study was conducted to investigate the occurrence of Soil borne wheat mosaic virus(SbWMV) in barley fields in Korea and to examine the host pathogenicity of SbWMV. By using the ELISA test, SbWMV was detected in the six regions : Suwon, Milyang, Jinju, Youngkwang, Iksan, and Chonju. SbWMV was isolated from the two strains, Albori strain from Jinju and Eunpamil strain from Milyang. SbWMV was collected from leaves showing mosaic, yellowing and necrosis stripes. SbWMV was inoculated mechanically on 1∼1.5 leaf stages with leaf-rubbing to identify the host pathogenicity of 36 Korean barley cultivars, a wheat cultivar, two rye cultivars, three Japanese barley cultivars and Chenopodium amaranticola. Viral sympoms of inoculated leaves appeared on moulted loaves about 4 to 6 weeks of inoculation. Baegdong and Tapgolbori, infected from Albori strain and Eunpamil strain infected from Samdobori showed much higher susceptibility than C. amaranticola and C. quinoa which showed ring spots and chlorotic spots respectively. Virus particles were observed by the electron microscope. They were rod-shapes, which are bipartite, of 142 nm or 281 nm in length with 20 nm diameter on infected leaves. Specific detection and identification of SbWMV was set up using the RT-PCR. PCR fragments of SbWMV(0.5kb) were obtained by using the designed primers for SbWMV RNA 2.

• Biomolecules & Therapeutics
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• v.27 no.2
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• pp.201-209
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• 2019

Mixed lineage leukemia proteins (MLL) are the key histone lysine methyltransferases that regulate expression of diverse genes. Aberrant activation of MLL promotes leukemia as well as solid tumors in humans, highlighting the urgent need for the development of an MLL inhibitor. We screened and isolated MLL1-binding ssRNAs using SELEX (${\underline{S}}ystemic$ ${\underline{E}}volution$ of ${\underline{L}}igands$ by ${\underline{E}}xponential$ enrichment) technology. When sequences in sub-libraries were obtained using next-generation sequencing (NGS), the most enriched aptamers-APT1 and APT2-represented about 30% and 26% of sub-library populations, respectively. Motif analysis of the top 50 sequences provided a highly conserved sequence: 5'-A[A/C][C/G][G/U][U/A]ACAGAGGG[U/A]GG[A/C] GAGUGGGU-3'. APT1, APT2, and APT5 embracing this motif generated secondary structures with similar topological characteristics. We found that APT1 and APT2 have a good binding activity and the analysis using mutated aptamer variants showed that the site information in the central region was critical for binding. In vitro enzyme activity assay showed that APT1 and APT2 had MLL1 inhibitory activity. Three-dimensional structure prediction of APT1-MLL1 complex indicates multiple weak interactions formed between MLL1 SET domain and APT1. Our study confirmed that NGS-assisted SELEX is an efficient tool for aptamer screening and that aptamers could be useful in diagnosis and treatment of MLL1-mediated diseases.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.6
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• pp.891-895
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• 2019

Objective: Aim of present study was the set up of a fast and reliable protocol using species-specific markers for the quali-quantitative analysis of DNA and the detection of ruminant biological components in dairy products. For this purpose, the promoter of the gene coding for the ${\alpha}$-lactoalbumin (LALBA) was chosen as possible candidate for the presence of short interspersed nuclear elements (SINEs). Methods: DNA was isolated from somatic cells of 120 individual milk samples of cattle (30), Mediterranean river buffalo (30), goat (30), and sheep (30) and the gene promoter region (about 600/700 bp) of LALBA (from about 600 bp upstream of exon 1) has been sequenced. For the development of a single polymerase chain reaction (PCR) protocol that allows the simultaneous identification of DNA from the four species of ruminants, the following internal primers pair were used: 5'-CACTGATCTTAAAGCTCAGGTT-3' (forward) and 5'-TCAGA GTAGGCCACAGAAG-3' (reverse). Results: Sequencing results of LALBA gene promoter region confirmed the presence of SINEs as monomorphic "within" and variable in size "among" the selected species. Amplicon lengths were 582 bp in cattle, 592 bp in buffalo, 655 in goat and 729 bp in sheep. PCR specificity was demonstrated by the detection of trace amounts of species-specific DNA from mixed sources ($0.25ng/{\mu}L$). Conclusion: We developed a rapid PCR protocol for the quali-quantitative analysis of DNA and the traceability of dairy products using a species-specific marker with only one pair of primers. Our results validate the proposed technique as a suitable tool for a simple and inexpensive (economic) detection of animal origin components in foodstuffs.

• Journal of Ginseng Research
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• v.43 no.2
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• pp.291-299
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• 2019

Background: Ginsenosides of Korean Red Ginseng extracts (RGE) and its saponin components suppress secretion of inflammasome-mediating cytokines, whereas the nonsaponin fraction (NS) of RGE oppositely stimulates cytokine secretion. Although direct exposure of NS to macrophages in mice induces cytokine production, oral administration of NS has not been studied in inflammasome-related disease in animal models. Methods: Mice were fed RGE or NS for 7 days and then developed peritonitis. Peritoneal cytokines were measured, and peritoneal exudate cells (PECs) were collected to assay expression levels of a set of toll-like receptors (TLRs) and cytokines in response to NS ingestion. In addition, the role of intestinal bacteria in NS-fed mice was assessed. The effect of preexposure to NS in bone marrow-derived macrophages (BMDMs) on cytokine production was further confirmed. Results: NS ingestion attenuated secretion of peritoneal cytokines resulting from peritonitis. In addition, the isolated PECs from NS-fed mice presented lower TLR transcription levels than PECs from control diet-fed mice. BMDMs treated with NS showed downregulation of TLR4 mRNA and protein expression, which was mediated by the $TLR4-MyD88-NF{\kappa}B$ signal pathway. BMDMs pretreated with NS produced less cytokines in response to TLR4 ligands. Conclusion: NS administration directly inhibits TLR4 expression in inflammatory cells such as macrophages, thereby reducing secretion of cytokines during peritonitis.