Search results for "HIF"
showing 10 items of 1515 documents
HIF-1 is involved in the negative regulation of AURKA expression in breast cancer cell lines under hypoxic conditions
2013
Numerous microarray-based gene expression studies performed on several types of solid tumors revealed significant changes in key genes involved in progression and regulation of the cell cycle, including AURKA that is known to be overexpressed in many types of human malignancies. Tumor hypoxia is associated with poor prognosis in several cancer types, including breast cancer (BC). Since hypoxia is a condition that influences the expression of many genes involved in tumorigenesis, proliferation, and cell cycle regulation, we performed a microarray-based gene expression analysis in order to identify differentially expressed genes in BC cell lines exposed to hypoxia. This analysis showed that h…
Tumor and its microenvironment: a synergistic interplay.
2013
The mutual and interdependent interaction between tumor and its microenvironment is a crucial topic in cancer research. Recently, it was reported that targeting stromal events could improve efficacies of current therapeutics and prevent metastatic spreading. Tumor microenvironment is a "complex network" of different cell types, soluble factors, signaling molecules and extracellular matrix components, which orchestrate the fate of tumor progression. As by definition, cancer stem cells (CSCs) are proposed to be the unique cell type able to maintain tumor mass and survive outside the primary tumor at metastatic sites. Being exposed to environmental stressors, including reactive oxygen species …
Hypoxia-induced epithelial VEGF-C/VEGFR-3 upregulation in carcinoma cell lines
2008
Adaptation to hypoxia, a universal hallmark of carcinomas, is a critical step for tumor cell survival and growth. One of the principal regulators of hypoxia-responsive pathways is the transcription factor hypoxia-inducible factor-1 alpha (HIF-1 alpha). Currently, it is known that tumoral production of members of the vascular endothelial growth factor (VEGF)-family (VEGFs) may promote tumor growth and progression by acting on carcinoma cells that express the cognate receptors (VEGFRs). However, the influence of hypoxia in the formation of such a tumoral VEGF/VEGFR loop is not completely understood. In the present study we examined the potential existence of a HIF-1 alpha/VEGF/VEGFR autocrine…
Power-Line Communication in Medium-Voltage System: Simulation Model and Onfield Experimental Tests
2012
The aim of this paper is to develop a complete model of a power-line communication (PLC) system operating on a medium-voltage (MV) network. The core-shield configuration was chosen for signal transmission in the power cables. In order to validate the developed model experimental, the medium-voltage network of the Favignana island was used to carry out detailed testing. The transmission was performed between two transformer substations in the presence of mains voltage (i.e., 24 kV). ST7540 FSK power-line transceivers, together with capacitive coupling interfaces, were used for the transmission and the reception of the communication signal. The correlation between the experimental measurement…
Substituent effect of nitro group on aromaticity of carbazole rings
2014
The molecular geometries of carbazole and its 17 nitro derivatives were optimized at the B3LYP/6-311++G(2d,2p) level of theory. The harmonic oscillator model of aromaticity and nucleus-independent chemical shift descriptors of π-electron delocalization were calculated to estimate the aromaticity of the carbazole five- and six-membered rings. The biggest changes in the value of both descriptors were observed for the pyrrole ring. The nitro group attached to 3 and/or 6 positions of the carbazole ring system exerts only a slight influence on the benzene ring aromaticity.
1H, 13C and 15N NMR spectral characterization of twenty-seven 1,2-diaryl-(4E)-arylidene-2-imidazolin-5-ones.
2006
1H, 13C and 15N NMR chemical shifts and couplings nJ(H,C) in DMSO-d6 at 30 °C have been determined for 1,2-diaryl-(4E)-arylidene-2-imidazolin-5-one derivatives 1–27. Their chemical shift assignments are based on PFG DQF 1H,1H COSY, PFG 1H,13C HMQC as well as PFG 1H,13C and 1H,15N HMBC experiments. For compounds 1–10 including aryl fluorine substituent(s) also the couplings nJ(F,C) (n = 1 − 4) are reported. Copyright © 2006 John Wiley & Sons, Ltd.
Complete 1H and 13C NMR assignments of clerodane diterpenoids of Salvia splendens.
2006
Unambiguous and complete assignments of 1H and 13C NMR chemical shifts for five clerodane diterpenes, four of them isolated from Salvia splendens (salviarin, splendidin and splenolides A and B) and one obtained by acetylation of splenolide A, are presented. The assignments are based on 2D shift-correlated [1H,1H–COSY, 1H,13C-gHSQC–1J(C,H) and 1H,13C-gHMBC-nJ(C,H) (n = 2 and 3)] and nuclear Overhauser effect (NOE) experiments. The conformation of the rings of these compounds is supported by the 3J(H,H) values and NOE results. Copyright © 2006 John Wiley & Sons, Ltd.
Effect of electron-withdrawing substituents on the electrophilicity of carbonyl carbons
2005
Indexación: Scopus The substituent effects on the carbonyl carbon atom for a series of twelve substituted phenyl acetates have been rationalized using a global electrophilicity index. This index is linearly correlated with the experimental reaction rate coefficients. We found that, in contrast to the proposed interpretation based on experimental 13C NMR chemical shifts and ground state destabilization calculations, the electrophilicity of carbonyl compounds increases due to the effect promoted by electron-withdrawing groups in these systems. https://www.sciencedirect.com/science/article/pii/S0040402004018046?via%3Dihub
Über gemischte gruppe 14-gruppe 14-bindungen
1993
Abstract The lead-tin compounds o-Tol6PbSn, o-Tol3PbSnPh3 and Mes3PbSnPh3 have been synthesized from Li and halide precursors in THF/ether at low temperatures. The crystal structures of the S4 symmetric o-Tol4Pb and of the three isomorphous title compounds have been determined (d(SnSn) 2.883 (1), d (PbSn) 2.845 (2), d (PbPb) 2.895 (2), A). The long SnSn distance is in accordance with the Raman data for the pairs of p-Tol6/o-Tol6 substituents (ν(SnSn) 131/123, ν(PbSn) 114/114, ν(PbPb) 105/103 cm−1). The sequence of the 119Sn and 207Pb chemical shifts shows clearly a polarity Pbδ−Snδ+ for all lead-tin compounds investigated. The 1J (119Sn207Pb) and 1J(119Sn119Sn) couplings of identi…
Microstructure-specific carbon isotopic signatures of organic matter from ∼3.5 Ga cherts of the Pilbara Craton support a biologic origin.
2016
21 pages; International audience; The ∼3.5 Ga Dresser Formation from the North Pole Dome of the Pilbara Craton (Western Australia) contains some of the oldest evidence for life on Earth. Here, we present a detailed study of microstructure-specific carbon isotopic composition of organic matter (OM) preserved in Dresser Formation bedded cherts and hydrothermal chert vein using in situ Secondary-Ion Mass Spectrometry (SIMS). The OM in these rocks occurs mainly as clots that, together with minor fine OM layers and laminae, are considered primary textures formed prior to host rock lithification. Other than rare OM-rich stylolites, no evidence was found for later OM migration beyond the micromete…