Search results for " base"
showing 10 items of 1811 documents
The interaction of native DNA with iron(III)- N ,N'-ethylene-bis(salicylideneiminato)-chloride.
2004
Abstract The interaction between native calf thymus deoxyribonucleic acid (DNA) and Fe III - N , N ′ -ethylene-bis (salicylideneiminato)-chloride, Fe(Salen)Cl, was investigated in aqueous solutions by UV–visible (UV–vis) absorption, circular dichroism (CD), thermal denaturation and viscosity measurements. The results obtained from CD, UV–vis and viscosity measurements exclude DNA intercalation and can be interpreted in terms of an electrostatic binding between the Fe(Salen) + cation and the phosphate groups of DNA. The trend of the UV–vis absorption band of the Fe(Salen)Cl complex at different ratios [DNA phosphate ]/[Fe(Salen)Cl] and the large increase of the melting temperature of DNA in …
The interaction of native DNA with Zn(II) and Cu(II) complexes of 5-triethyl ammonium methyl salicylidene orto-phenylendiimine
2007
The interaction of native calf thymus DNA with the Zn(II) and Cu(II) complexes of 5-triethyl ammonium methyl salicylidene orto-phenylendiimine (ZnL(2+) and CuL(2+)), in 1 mM Tris-HCl aqueous solutions at neutral pH, has been monitored as a function of the metal complex-DNA molar ratio by UV absorption spectrophotometry, circular dichroism (CD) and fluorescence spectroscopy. The results support for an intercalative interaction of both ZnL(2+) and CuL(2+) with DNA, showing CuL(2+) an affinity of approximately 10 times higher than ZnL(2+). In particular, the values of the binding constant, determined by UV spectrophotometric titration, equal to 7.3x10(4) and 1.3x10(6)M(-1), for ZnL(2+) and CuL…
Another step toward DNA selective targeting: NiII and CuII complexes of a Schiff base ligand able to bind gene promoter G-quadruplexes
2016
DNA G-rich sequences are able to form four-stranded structures organized in stacked guanine tetrads. These structures, called G-quadruplexes, were found to have an important role in the regulation of oncogenes expression and became, for such a reason, appealing targets for anticancer drugs. Aiming at finding selective G-quadruplex binders, we have designed, synthesized and characterized a new water soluble Salen-like Schiff base ligand and its NiII and CuII metal complexes. UV-Vis, circular dichroism and FRET measurements indicated that the nickel complex can stabilize oncogene promoter G-quadruplexes with high selectivity, presenting no interactions with duplex DNA at all. The same compoun…
Formation of a novel ferromagnetic end-to-end cyanate bridged homochiral helical copper(ii) Schiff base complex via spontaneous symmetry breaking
2014
A homochiral helical coordination polymer of copper(II) has been synthesized using achiral precursors via spontaneous symmetry breaking and has been confirmed by single crystal X-ray diffraction and solid-state CD spectroscopy. The variable temperature magnetic measurements indicate the presence of weak ferromagnetic exchange interactions mediated by end-to-end cyanate bridges (J = +0.12 cm(-1)).
Nickel(II), copper(II) and zinc(II) metallo-intercalators: structural details of the DNA-binding by a combined experimental and computational investi…
2014
We present a thorough characterization of the interaction of novel nickel(II) (1), copper(II) (2) and zinc(II) (3) Schiff base complexes with native calf thymus DNA (ct-DNA), in buffered aqueous solution at pH 7.5. UV-vis absorption, circular dichroism (CD) and viscometry titrations provided clear evidence of the intercalative mechanism of the three square-planar metal complexes, allowing us to determine the intrinsic DNA-binding constants (K(b)), equal to 1.3 × 10(7), 2.9 × 10(6), and 6.2 × 10(5) M(-1) for 1, 2 and 3, respectively. Preferential affinity, of one order of magnitude, toward AT compared to GC base pair sequences was detected by UV-vis absorption titrations of 1 with [poly(dG-d…
Recursive partitioning: an approach based on the weighted kemeny distance
2015
In the framework of preference rankings, the interest can lie in finding which predictors and which interactions are able to explain the observed preference structures. The possibility to derive consensus measures using a classification tree represents a novelty and an important tool, given its easy interpretability. This work proposes the use of a univariate decision tree for ranking data based on the weighted Kemeny distance. The performance of the methodology will be shown by using a real dataset about university rankings.
Clima motivacional, motivación y cohesión: Un estudio en el fútbol base
2015
* Climas motivacionales * Motivación * Cohesión * Fútbol base Según el Consejo Superior de Deportes (CSD) un gran número de niños y niñas durante su infancia realizan una práctica deportiva como actividad cotidiana en nuestro país, en concreto el fútbol es el deporte más practicado entre los jóvenes (CSD, 2011; García Ferrando y Llopis, 2011), pero resulta preocupante que la participación deportiva empiece a disminuir alrededor de los 11 años y continúa a lo largo de la adolescencia (Balaguer, 1999, 2002; Castillo y Balaguer, 1998; Wankel y Mummery, 1996). Estos resultados son significativos, porque, entre otras cosas, pueden estar sugiriendo que los contextos deportivos podrían no ofrecer …
Virtual reality in the treatment of claustrophobic fear: A controlled, multiple-baseline design
2000
The aim of this study was to determine the effectiveness of virtual reality (VR) exposure in the treatment of claustrophobic fear. We evaluated the intervention following a controlled, multiple-baseline design across 4 participants with claustrophobic fear who sought psychological help in our anxiety disorders clinic. The treatment consisted of 8 individual VR graded exposure sessions. Data were obtained at pretreatment, posttreatment, and 3-month follow-up on several clinical measures: Behavioral Avoidance Test, Self-Efficacy Toward Closed Spaces, Problem-Related Impairment Questionnaire, Beck Depression Inventory (Beck, 1978), and Anxiety Sensitivity Index (Peterson & Reiss, 1992). Result…
Manufacturing, characterization and control of cell-based medicinal products: challenging paradigms toward commercial use
2015
During the past decade, a large number of cell-based medicinal products have been tested in clinical trials for the treatment of various diseases and tissue defects. However, licensed products and those approaching marketing authorization are still few. One major area of challenge is the manufacturing and quality development of these complex products, for which significant manipulation of cells might be required. While the paradigms of quality, safety and efficacy must apply also to these innovative products, their demonstration may be demanding. Demonstration of comparability between production processes and batches may be difficult for cell-based medicinal products. Thus, the development …
Factors influencing inclusion in digestive cancer clinical trials: A population-based study
2015
Inclusion in a randomized therapeutic trial represents an optimal therapeutic strategy.To determine the influence of demographic characteristics and deprivation on the enrolment of patients in digestive cancer clinical trials.Between 2004 and 2010, 4632 patients were recorded by the Burgundy Digestive Cancer Registry. According to a balancing score, the 136 patients included in a clinical trial were matched with 272 patients who met the eligibility criteria for trials. Deprivation was measured by the ecological European deprivation index. A conditional multivariate logistic regression was performed.Patients aged over 75 years were significantly less likely to be included in clinical trials …