5,731 research outputs found

    A Note on the Edge Roman Domination in Trees

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    A subset XX of edges of a graph GG is called an \textit{edgedominating set} of GG if every edge not in XX is adjacent tosome edge in XX. The edge domination number γ(G)\gamma'(G) of GG is the minimum cardinality taken over all edge dominating sets of GG. An \textit{edge Roman dominating function} of a graph GG is a function f:E(G){0,1,2}f : E(G)\rightarrow \{0,1,2 \} such that every edgeee with f(e)=0f(e)=0 is adjacent to some edge ee' with f(e)=2.f(e') = 2.The weight of an edge Roman dominating function ff is the valuew(f)=eE(G)f(e)w(f)=\sum_{e\in E(G)}f(e). The edge Roman domination number of GG, denoted by γR(G)\gamma_R'(G), is the minimum weight of an edge Roman dominating function of GG. In this paper, we characterize trees with edge Roman domination number twice the edge domination number

    Identification of novel genes involved in gastric carcinogenesis by suppression subtractive hybridization

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    Gastric cancer (GC) is one of the most common and life-threatening types of malignancies. Identification of the differentially expressed genes in GC is one of the best approaches for establishing new diagnostic and therapeutic targets. Furthermore, these investigations could advance our knowledge about molecular biology and the carcinogenesis of this cancer. To screen for the overexpressed genes in gastric adenocarcinoma, we performed suppression subtractive hybridization (SSH) on gastric adenocarcinoma tissue and the corresponding normal gastric tissue, and eight genes were found to be overexpressed in the tumor compared with those of the normal tissue. The genes were ribosomal protein L18A, RNase H2 subunit B, SEC13, eukaryotic translation initiation factor 4A1, tetraspanin 8, cytochrome c oxidase subunit 2, NADH dehydrogenase subunit 4, and mitochondrially encoded ATP synthase 6. The common functions among the identified genes include involvement in protein synthesis, involvement in genomic stability maintenance, metastasis, metabolic improvement, cell signaling pathways, and chemoresistance. Our results provide new insights into the molecular biology of GC and drug discovery: each of the identified genes could be further investigated as targets for prognosis evaluation, diagnosis, treatment, evaluation of the response to new anticancer drugs, and determination of the molecular pathogenesis of GC. © The Author(s) 2014

    Genome expression analysis by suppression subtractive hybridization identified overexpression of Humanin, a target gene in gastric cancer chemoresistance

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    Background: In cancer cells, apoptosis is an important mechanism that influences the outcome of chemotherapy and the development of chemoresistance. To find the genes involved in chemoresistance and the development of gastric cancer, we used the suppression subtractive hybridization method to identify the genes that are overexpressed in gastric cancer tissues compared to normal gastric tissues. Results: In the suppression subtractive hybridization library we constructed, the most highly overexpressed genes were humanin isoforms. Humanin is a recently identified endogenous peptide that has anti-apoptotic activity and has been selected for further study due to its potential role in the chemoresistance of gastric cancer. Upregulation of humanin isoforms was also observed in clinical samples by using quantitative real-time PCR. Among the studied isoforms, humanin isoform 3, with an expression level of 4.166 ± 1.44 fold, was the most overexpressed isoform in GC. Conclusions: The overexpression of humanin in gastric cancer suggests a role for chemoresistance and provides new insight into the biology of gastric cancer. We propose that humanin isoforms are novel targets for combating chemoresistance in gastric cancer. © 2014 Mottaghi-Dastjerdi et al.; licensee BioMed Central Ltd

    Generating a synthetic population in support of agent-based modeling of transportation in Sydney

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    The complexity of large cities such as Sydney makes planning challenging. There is a growing need for new and evolving tools to assist research and decision-making. Increasingly, planners require sophisticated insights on social behaviour and the interdependencies characterising urban systems. Agent-based modelling as a large and wide-spread scientific modelling technique (that focuses on computer modelling of individuals and their interactions) has recently emerged as a promising tool in this regard with applications to real-world problems in infrastructure, particularly transport planning, of urban areas. An essential element of such an agent based model is a realistic synthetic population that matches the distribution of individuals and households living in a study area as per the demographics from census data. This paper presents an algorithm to construct such a synthetic population that uses only aggregated data of demographic distributions as inputs, and an agent based model which simulates the natural evolutions (ageing, marriage, divorce, reproducing) of this initial population. The significance of the synthetic population developed in this work is in its ability to capture the relationship of individuals in a household and changes in structure of households as individuals undergo natural evolutions. A case study that uses the algorithm to initialise a synthetic population for Randwick (Sydney) in 2006 and evolve this population over 5 years will also be presented. The results of the initial and final population were validated against the Census Data in 2006 and 2011. The paper closes with discussions on the application of this synthetic population to simulate the dynamics interaction between transport and land-use. (Résumé d'auteur

    Overexpression of microRNA-16 declines cellular growth, proliferation and induces apoptosis in human breast cancer cells

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    MicroRNAs (miRNA) are a large family of small single-stranded RNA molecules found in all multicellular organisms. Early studies have been shown that miRNA are involved in cancer development and progression, and this role can be done by working as an oncogenes and tumor suppressor genes, so manipulation of this molecules can be a promising approach in cancer therapy, and experimental results represented that the modification in breast cancer phenotype is possible by miRNA expression alteration. miR-16, which is located in 13q14 chromosome, plays critical roles as a tumor suppressor by targeting several oncogenes which regulate cell cycle and apoptosis. Hence, in the present study, we investigated whether miR-16 could decline growth and survival of MCF-7 cell line as model of human breast cancer. MCF-7 cell line was infected with lentiviruses containing miR-16 precursor sequence. The effects of ectopic expression of miR-16 on breast cancer phenotype were examined by cell cycle analysis and apoptosis assays. miR-16 cytotoxicity effect was measured by the MTT assay. We showed that the miR-16 overexpression reduces Cyclin D1 and BCL2 at messenger RNA (mRNA) and protein levels in MCF-7 cell line. In addition, this is found that enforced expression of miR-16 decreases cell growth and proliferation and induces apoptosis in MCF-7 cells. In conclusion, our results revealed that upregulation of miR-16 would be a potential approach for breast cancer therapy. © 2015, The Society for In Vitro Biology

    Carbon Sources and Water-Rock Interactions in the Allier River, France

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    AbstractThe Allier River is an important tributary of the Loire River, one of the major rivers in France. The Allier River presents both a natural environment upstream and a zone deeply impacted by mines and human activities. The δ13C and δ7Li combination show that the Allier River DIC is due to mixing of carbon from organic decay produced in a natural environment upstream, progressively enriched in DIC of anthropogenic origin downstream, and magmatic carbon inputs often associated with hydrothermal contributions

    Irradiation-induced confinement in a quasi-one-dimensional metal

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    The anisotropic resistivity of PrBa2_2Cu4_4O8_8 has been measured as a function of electron irradiation fluence. Localization effects are observed for extremely small amounts of disorder corresponding to electron mean-free-paths of order 100 unit cells. Estimates of the localization corrections suggest that this anomalous localization threshold heralds a crossover to a ground state with pronounced one-dimensional character in which conduction electrons become confined to a small cluster of chains.Comment: 4 pages, 4 figure

    Possible co-existence of local itinerancy and global localization in a quasi-one-dimensional conductor

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    In the chain compound PrBa2_2Cu4_4O8_8 localization appears simultaneously with a dimensional crossover in the electronic ground state when the scattering rate in the chains exceeds the hopping rate between the chains. Here we report the discovery of a large, transverse magnetoresistance in PrBa2_2Cu4_4O8_8 in the localized regime. This result suggests a novel form of localization whereby electrons retain their metallic (quasi-one-dimensional) character over a microscopic length scale despite the fact that macroscopically, they exhibit localized (one-dimensional) behavior.Comment: 4 pages, 4 Figure
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