Search results for "cycle"
showing 10 items of 3119 documents
A study of the interaction between iron(III)oxide and titanium(IV)oxide at elevated temperatures
1991
Abstract The bulk interaction between iron(III) oxide and titanium(IV) oxide occurs at temperatures in excess of 773 K. Initially iron(III) ions dissolve in the titanium(IV) oxide structure to produce a substitutional solid solution. Magnetic evidence suggests that there is a solubility limit of iron(III) ions in the region of ca. 3 atom %. Significantly the phase transition from the anatase phase to the rutile phase is observed to occur approximately 200 K lower in the presence of iron than when it is absent. Further reaction between iron(III) oxide and the saturated solution in the rutile phase occurs at 1073 K with the formation of pseudo-brookite. Under high vacuum conditions the therma…
Novel 3-Azaindolyl-4-arylmaleimides Exhibiting Potent Antiangiogenic Efficacy, Protein Kinase Inhibition, and Antiproliferative Activity
2012
Tumor growth and metastasis are highly associated with the overexpression of protein kinases (PKs) regulating cell growth, apoptosis resistance, and prolonged cell survival. This study describes novel azaindolyl-maleimides with significant inhibition of PKs, such as VEGFR, FLT-3, and GSK-3β which are related to carcinogenesis. Furthermore, these compounds exhibit high kinase selectivity and potent inhibition of angiogenesis and cell proliferation, offering versatile options in cancer treatment strategies.
Transcriptome data reveal syndermatan relationships and suggest the evolution of endoparasitism in acanthocephala via an epizoic stage
2014
The taxon Syndermata comprises the biologically interesting wheel animals ("Rotifera": Bdelloidea + Monogononta + Seisonidea) and thorny-headed worms (Acanthocephala), and is central for testing superordinate phylogenetic hypotheses (Platyzoa, Gnathifera) in the metazoan tree of life. Recent analyses of syndermatan phylogeny suggested paraphyly of Eurotatoria (free-living bdelloids and monogononts) with respect to endoparasitic acanthocephalans. Data of epizoic seisonids, however, were absent, which may have affected the branching order within the syndermatan clade. Moreover, the position of Seisonidea within Syndermata should help in understanding the evolution of acanthocephalan endoparas…
Protection by extra virgin olive oil against oxidative stress in vitro and in vivo. Chemical and biological studies on the health benefits due to a m…
2017
Abstract We report the results of in vivo studies in Caenorhabditis elegans nematodes in which addition of extra virgin olive oil (EVOO) to their diet significantly increased their life span with respect to the control group. Furthermore, when nematodes were exposed to the pesticide paraquat, they started to die after two days, but after the addition of EVOO to their diet, both survival percentage and lifespans of paraquat-exposed nematodes increased. Since paraquat is associated with superoxide radical production, a test for scavenging this radical was performed using cyclovoltammetry and the EVOO efficiently scavenged the superoxide. Thus, a linear correlation (y = -0.0838x +19.73, regres…
Switchable Access to Different Spirocyclopentane Oxindoles by N-Heterocyclic Carbene Catalyzed Reactions of Isatin-Derived Enals and N-Sulfonyl Ketim…
2017
A novel NHC-catalyzed annulation protocol for the asymmetric synthesis of biologically important β-lactam fused spirocyclopentane oxindoles with four contiguous stereocenters, including two quaternary carbon centers, was developed. Alternatively, spirocyclopentane oxindoles containing an enaminone moiety can be achieved using the same starting materials, isatin-derived enals, and N-sulfonyl ketimines, in the presence of a slightly different NHC catalytic system. This switchable annulation strategy enables the selective assembly of both heterocyclic scaffolds with good yields and excellent enantioselectivities for a broad range of substrates.
Efficient two-step synthesis of face-to-face meso-substituted bis(corrole) dyads
2008
The synthesis of face-to-face meso-substituted bis(corrole) systems was revisited. By using a new synthetic pathway, the reaction was generalized to any type of linker and the yield was considerably increased. The dyads were obtained in yields up to 20 % from a dialdehyde linker and dipyrromethane in a one-step reaction. The best reaction conditions required a decreased amount of TFA catalyst (1.4 equiv.) and a large excess of dipyrromethane (up to 8 equiv). Under these conditions, four bis(corrole)s linked by 2,2′-diphenyl ether, 9,9-dimethylxanthene, anthracene, and dibenzofuran spacers were synthesized.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Anti-cancer activity of di- and tri-organotin(IV) compounds with D-(+)-Galacturonic acid on human tumor cells
2018
Abstract We have compared the anti-proliferative activity in vitro, of R2SnGala (1-3) [R = Me, n-Bu, Ph] and novel R3SnGala (4, 5) [R = Me, n-Bu] with D-(+)-Galacturonic acid [HGala; Galaq-, q = (2) and (1) for R2SnGala and R3SnGala, respectively] compounds, towards human tumor cell lines of intestinal carcinoma (HCT-116) and breast adenocarcinoma (MCF-7). The new synthesized 4 and 5 compounds were characterized, in solution, by 1H, 13C and 119Sn NMR, that showed that HGala acts as monoanionic moiety and evidenced the dynamic behavior of the compounds, due to inter-conversions involving the anomeric carbon atom of the ligand. Cell viability, apoptosis induction and cell cycle distribution w…
Depletion of alloreactive T cells via CD69: implications on antiviral, antileukemic and immunoregulatory T lymphocytes
2005
Selective depletion of alloreactive T cells from stem-cell allografts should abrogate graft-versus-host disease while preserving beneficial T cell specificities to facilitate engraftment and immune reconstitution. We therefore explored a refined immunomagnetic separation strategy to effectively deplete alloreactive donor lymphocytes expressing the activation antigen CD69 upon stimulation, and examined the retainment of antiviral, antileukemic, and immunoregulatory T cells. In addition to the CD69high T cell fraction, our studies retrieved two T cell subsets based on residual CD69 expression. Whereas, truly CD69(neg) cells were devoid of detectable alloresponses to original stimulators, CD69…
Glutathione metabolism in primary astrocyte cultures: flow cytometric evidence of heterogeneous distribution of GSH content.
1993
The time-course of intracellular glutathione (GSH) values after incubation with L-buthionine-(S,R)-sulfoximine (BSO), a selective inhibitor of gamma-glutamylcysteine synthetase, showed that glutathione turns over with a half-life of 5 h. Intracellular GSH was assayed by flow cytometry using three different methods. Astrocytes showed a narrow range of cellular size but a wide range of intracellular GSH. This heterogeneity was resolved into three distinct subpopulations which represent 20%, 35% and 45% of the total astrocyte number. The less abundant subpopulation had the lower GSH content, while the most abundant was the subpopulation with the higher content. Over 95% of astrocytes were in t…
Stilbene-based anticancer agents: Resveratrol analogues active toward HL60 leukemic cells wit a non-specific phase mechanism
2006
Several stilbenes, related to known resveratrol, have been synthesized and tested for their anticancer effect on HL60 leukemia cell line, taking particular care of the cell cycle analysis. The most potent compound was the known (Z)-3,4',5-trimethoxystilbene (6b) which was active as apoptotic agent at 0.24 microM. Differently from other stilbenes (including resveratrol) that induced a prevalent recruitment of cells in S phase of cell cycle, we found a peculiar behavior of 6b that caused a decrease of cells in all phases of cell cycle (G0-G1, S, and G2-M) and a proportional increase of apoptotic cells. The potent pro-apoptotic activity shown by compound 6b and its effects on cell cycle make t…