4,674 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

    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

    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

    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

    Dimensionality-driven spin-flop transition in quasi-one-dimensional PrBa2Cu4O8

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    In the quasi-one-dimensional cuprate PrBa2_2Cu4_4O8_8, the Pr cations order antiferromagnetically at 17 K in zero field. Through a combination of magnetic susceptibility, torque magnetometry, specific heat and interchain transport measurements, the anisotropic temperature-magnetic field phase diagram associated with this ordering has been mapped out. A low-temperature spin-flop transition in the Pr sub-lattice is found to occur at the same magnetic field strength and orientation as a dimensional crossover in the ground state of the metallic CuO chains. This coincidence suggests that the spin reorientation is driven by a change in the anisotropic Rudermann-Kittel-Kasuya-Yosida (RKKY) interaction induced by a corresponding change in effective dimensionality of the conduction electrons.Comment: 8 pages, 8 figure