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Search Results: 1 - 10 of 25269 matches for " Younghee Lee "
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Nickel Oxide/Carbon Nanotubes Nanocomposite for Electrochemical Capacitance
Kui LIANG,Kayhyeok AN,Younghee LEE,
Kayhyeok AN
,Younghee LEE

材料科学技术学报 , 2005,
Abstract: A nanocomposite of nickel oxide/carbon nanotubes was prepared through a simple chemical precipitation followed by thermal annealing. The electrochemical capacitance of this electrode material was studied. When the mass fraction of CNTs (carbon nanotubes) in NiO/CNT composites increases, the electrical resistivity of nanocomposites decreases and becomes similar to that of pure CNTs when it reaches 30%. The specific surface area of composites increases with increasing CNT mass fraction and the specific capacitance reaches 160 F/g under 10 mA/g discharge current density at CNT mass fraction of 10%.
Stromal microenvironment processes unveiled by biological component analysis of gene expression in xenograft tumor models
Yang Xinan,Lee Younghee,Huang Yong,Chen James L
BMC Bioinformatics , 2010, DOI: 10.1186/1471-2105-11-s9-s11
Abstract: Background Mouse xenograft models, in which human cancer cells are implanted in immune-suppressed mice, have been popular for studying the mechanisms of novel therapeutic targets, tumor progression and metastasis. We hypothesized that we could exploit the interspecies genetic differences in these experiments. Our purpose is to elucidate stromal microenvironment signals from probes on human arrays unintentionally cross-hybridizing with mouse homologous genes in xenograft tumor models. Results By identifying cross-species hybridizing probes from sequence alignment and cross-species hybridization experiment for the human whole-genome arrays, deregulated stromal genes can be identified and then their biological significance were predicted from enrichment studies. Comparing these results with those found by the laser capture microdissection of stromal cells from tumor specimens resulted in the discovery of significantly enriched stromal biological processes. Conclusions Using this method, in addition to their primary endpoints, researchers can leverage xenograft experiments to better characterize the tumor microenvironment without additional costs. The Xhyb probes and R script are available at http://www.lussierlab.org/publications/Stroma
Some identities of the generalized twisted Bernoulli numbers and polynomials of highert order
Younghee Kim,Seog-Hoon Rim,Byungje Lee,Taekyun Kim
Mathematics , 2009,
Abstract: The purpose of this paper is to derive some identities of the higher order generalized twisted Bernoulli numbers and polynomials attached to $\chi$ from the properties of the p-adic invariant integrals.
On p-adic analogue of q-Bernstein polynomials and related integrals
Taekyun Kim,Lee-Chae jang,Younghee Kim,Jongsoung Choi
Mathematics , 2010,
Abstract: In this paper, we give p-adic q-integral representation for the Kim's q-Bernstein polynomials and we give some interesting formulae realted to Carlitz's q-Bernoulli numbers.
Detection of Listeria monocytogenes in Foods and Characterization by PFGE  [PDF]
Sanghun Park, Hyowon Jung, Myungsuk Lee, Heejin Choi, Jimin Kim, Jihun Jung, Sungkyu Park, Musang Kim, Kyungsik Kim, Younghee Oh, Aehee Chung, Kweon Jung
Advances in Microbiology (AiM) , 2016, DOI: 10.4236/aim.2016.64033
Abstract: The aims of the present study were to investigate the prevalence of Listeria monocytogenes in 1042 foods collected from different market to characterize the isolates by phenotypical and molecular methods. In particular, L. monocytogenes obtained from different types of foods such as RTE (kimbap), fish (smoked salmon and seasoned-dried slice fish) and meat (cut raw beef and pork) from 2009 to 2011, were used. Twelve samples (2.1%) were positive for L. monocytogenes. Detection rate of L. monocytogenes varied significantly by food type and ranged from 1.1% to 5.2%. Meat is the highest prevalence for L. monocytogenes (5.2%) followed by RTE (1.8%) and Fish (1.1%). Twelve isolates were also serotyped by the agglutination method. The most common serotypes detected in the 12 strains tested were 1/4b (75.0%), followed by 1/2a (16.7%), and 1/2b (8.3%). For this study, we used serotyping and detected 6 different virulence-associated genes (inlA, inlB, plcA, plcB, hlyA, and actA) and 16s rRNA using multiplex-PCR. PFGE was performed to determine genetic characterization of L. monocytogenes strains to define the genetic diversity.
Comparative Analysis of Pathogenicity Assays and PCR for Listeria monocytogenes Isolated from Animal, Raw Food and Environmental Sources in Korea  [PDF]
Sanghun Park, Jihun Jung, Younghee Oh, Jibho Lee, Seunghee Ryu, Hyowon Jung, Sunhee Park, Miok Song, Gunyong Park, Sungmin Choi, Sangmi Lee, Junghun Kim, YoungZoo Chae, Byungyeol Jung, Myunghun Lee, Hyunsoo Kim
Advances in Microbiology (AiM) , 2013, DOI: 10.4236/aim.2013.32029

Results of PCR with oligonucleotide primers were designed from the assembled panel of four potential virulence genes (two of internalin gene and two of transcriptional regulator gene). Most of the isolates including reference strains were reactive by PCR, whereas the other strains (No.80, 81, and 83) isolated from pork, were non-reactive by PCR. In particular, all pork isolates were PCR-negative for two primers (lmo2672 and 2821) sets tested. However, No.82 was positive for lmo1134 primer, and No.84 was positive for lmo2470 of pork isolates. It was observed that all Listeria monocytogenes (L. monocytogenes) penetrate Vero cells, although the invasion efficiency of each strain varied (between 0.5 and 18.9%). When compared in cell assay with PFGE, the results were shown that the mean invasion efficiency for lineage II isolate (2.6%) was significantly lower (ANOVA-test, p < 0.05) than that for lineage I (12.9%) and III isolates (10.3%).

Molecular Characterization of Listeria monocytogenes Based on the PFGE and RAPD in Korea  [PDF]
Sanghun Park, Jihun Jung, Sungsun Choi, Younghee Oh, Jibho Lee, Heesun Chae, Seunghee Ryu, Hyowon Jung, Gunyong Park, Sungmin Choi, Bogsoon Kim, Junghun Kim, Young Zoo Chae, Byungyeol Jung, Myunghun Lee, Hyunsoo Kim
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.24079

This study was performed to characterize 35 L. monocytogenes isolates from animals, foods, environmental samples collected between 1997 and 2007 with no apparent epidemiological relations, and five reference isolates using serotypic, genotypic and molecular typing methods to understand the pattern of strain distribution in Korea. For this study, we used serotyping and detected 6 different virulence-associated genes (inlA, inlB, plcA, plcB, hlyA, and actA) and 16s rRNA using multiplex-PCR. We also compared RAPD and PFGE to determine genetic characterization of L. monocytogenes strains to define the genetic diversity. Serotype patterns of the 30 L. monocytogenes strains was as follows; 9 isolates (30.0%) belonged to serotype, 7 isolates (23.3%) belonged to serotype 4b, 4 isolates (13.3%) belonged to serotype 1/2b, 3 isolates (10.0%) belonged to serotype 1/2c, 2 (6.7%) isolates belonged to4c, 2 (6.7%) isolates belonged to NT (Non Type), one isolate (3.2%) belonged to3aand 3b, and4a, respectively. Although, a limited number of isolates were analyzed in this study, molecular typing with RAPD and PFGE indicated that PFGE is more discriminatory for the subtyping L. monocytogenes than RAPD. Some L. monocytogenes isolates by RAPD and PFGE types are associated with specific sources. And, combining data obtained by these methods will increases the likelihood of strain discrimination.

Identification of common microRNA-mRNA regulatory biomodules in human epithelial cancer
XiNan Yang,Younghee Lee,Hong Fan,Xiao Sun,Yves A. Lussier
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-4051-1
Abstract: The complex regulatory network between microRNAs and gene expression remains an unclear domain of active research. We proposed to address in part this complex regulation with a novel approach for the genome-wide identification of biomodules derived from paired microRNA and mRNA profiles, which could reveal correlations associated with a complex network of dys-regulation in human cancer. Two published expression datasets for 68 samples with 11 distinct types of epithelial cancers and 21 samples of normal tissues were used, containing microRNA expression and gene expression profiles, respectively. As results, the microRNA expression used jointly with mRNA expression can provide better classifiers of epithelial cancers against normal epithelial tissue than either dataset alone (P=1×10 10, F-test). We identified a combination of 6 microRNA-mRNA biomodules that optimally classified epithelial cancers from normal epithelial tissue (total accuracy = 93.3%; 95% confidence intervals: 86%–97%), using penalized logistic regression (PLR) algorithm and three-fold cross-validation. Three of these biomodules are individually sufficient to cluster epithelial cancers from normal tissue using mutual information distance. The biomodules contain 10 distinct microRNAs and 98 distinct genes, including well known tumor markers such as miR-15a, miR-30e, IRAK1, TGFBR2, DUSP16, CDC25B and PDCD2. In addition, there is a significant enrichment (Fisher’s exact test P=3×10 10) between putative microRNA-target gene pairs reported in 5 microRNA target databases and the inversely correlated microRNA-mRNA pairs in the biomodules. Further, microRNAs and genes in the biomodules were found in abstracts mentioning epithelial cancers (Fisher’s Exact test, unadjusted P<0.05). Taken together, these results strongly suggest that the discovered microRNA-mRNA biomodules correspond to regulatory mechanisms common to human epithelial cancer samples. In conclusion, we developed and evaluated a novel comprehensive method to systematically identify, on a genome scale, microRNA-mRNA expression biomodules common to distinct cancers of the same tissue. These biomodules also comprise novel microRNA and genes as well as an imputed regulatory network, which may accelerate the work of cancer biologists as large regulatory maps of cancers can be drawn efficiently for hypothesis generation.
Differences in characteristics between healthcare-associated and community-acquired infection in community-onset Klebsiella pneumoniae bloodstream infection in Korea
Jung Younghee,Lee Myung,Sin Hye-Yun,Kim Nak-Hyun
BMC Infectious Diseases , 2012, DOI: 10.1186/1471-2334-12-239
Abstract: Background Healthcare-associated (HCA) infection has emerged as a new epidemiological category. The aim of this study was to evaluate the impact of HCA infection on mortality in community-onset Klebsiella pneumoniae bloodstream infection (KpBSI). Methods We conducted a retrospective study in two tertiary-care hospitals over a 6-year period. All adult patients with KpBSI within 48 hours of admission were enrolled. We compared the clinical characteristics of HCA and community-acquired (CA) infection, and analyzed risk factors for mortality in patients with community-onset KpBSI. Results Of 553 patients with community-onset KpBSI, 313 (57%) were classified as HCA- KpBSI and 240 (43%) as CA-KpBSI. In patients with HCA-KpBSI, the severity of the underlying diseases was higher than in patients with CA-KpBSI. Overall the most common site of infection was the pancreatobiliary tract. Liver abscess was more common in CA-KpBSI, whereas peritonitis and primary bacteremia were more common in HCA-KpBSI. Isolates not susceptible to extended-spectrum cephalosporin were more common in HCA- KpBSI than in CA-KpBSI (9% [29/313] vs. 3% [8/240]; p = 0.006). Overall 30-day mortality rate was significantly higher in HCA-KpBSI than in CA-KpBSI (22% [70/313] vs. 11% [27/240]; p = 0.001). In multivariate analysis, high Charlson’s weighted index of co-morbidity, high Pitt bacteremia score, neutropenia, polymicrobial infection and inappropriate empirical antimicrobial therapy were significant risk factors for 30-day mortality. Conclusions HCA-KpBSI in community-onset KpBSI has distinctive characteristics and has a poorer prognosis than CA-KpBSI, but HCA infection was not an independent risk factor for 30-day mortality.
Anomalous Lattice Dynamics of Mono-, Bi-, and Tri-layer WTe2
Younghee Kim,Young In Jhon,June Park,Jae Hun Kim,Seok Lee,Young Min Jhon
Physics , 2015,
Abstract: Tungsten ditelluride (WTe2) is a layered material that exhibits excellent magnetoresistance and thermoelectric behaviors, which are deeply related with its distorted orthorhombic phase that may critically affect the lattice dynamics. Here, for the first time, we present comprehensive characterization of the Raman spectroscopic behavior of WTe2 from bulk to monolayer using experimental and computational methods. We discover that mono and bi-layer WTe2 can be easily identified by Raman spectroscopy since double or single Raman modes that are observed in higher-layer WTe2 are substantially suppressed in the monolayer and bilayer WTe2, respectively. In addition, different from hexagonal metal dichalcogenides, the frequency of in-plane mode of WTe2 remains almost constant as the layer number decreases, while the other Raman modes consistently blueshift. First-principles calculation validates the experiments and reveals that the negligible shift of the mode is attributed to the lattice vibration along the tungsten chains that make WTe2 structurally one-dimensional.
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