Search results for "3-d"
showing 10 items of 1132 documents
Heptanuclear hydroxo-bridged copper cluster of the dicubane-like type: structural and magnetic characterisations of [Cu7(OH)6Cl2(pn)6(H2O)2](C(CN)3)4…
2002
A new polynuclear copper(II) complex [Cu7(OH)6Cl2- (pn)6(H2O)2](C(CN)3)4Cl2 with hydroxo-bridging ligands has been prepared; the centrosymmetric cluster cation can be described as two Cu4O3Cl distorted cubane units sharing one copper cation. Clemente Juan, Juan Modesto, Juan.M.Clemente@uv.es ; Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es
Nanocomplexes for gene therapy of respiratory diseases: Targeting and overcoming the mucus barrier
2015
Gene therapy, i.e. the delivery and expression of therapeutic genes, holds great promise for congenital and acquired respiratory diseases. Non-viral vectors are less toxic and immunogenic than viral vectors, although they are characterized by lower efficiency. However, they have to overcome many barriers, including inflammatory and immune mediators and cells. The respiratory and airway epithelial cells, the main target of these vectors, are coated with a layer of mucus, which hampers the effective reaching of gene therapy vectors carrying either plasmid DNA or small interfering RNA. This barrier is thicker in many lung diseases, such as cystic fibrosis. This review summarizes the most impor…
The 1,3-dipolar cycloaddition of 1H-pyridinium-3-olate and 1-methylpyridinium-3-olate with methyl acrylate: a density functional theory study
2010
The 1,3-dipolar cycloaddition reaction of 1-substituted pyridinium 3-olates with methyl acrylate is studied using density functional theory (DFT) method at the B3LYP/6-31G(d) level. The molecular mechanisms of the possible stereo- and regio-chemical pathways are characterized and explored. Solvent effects are also evaluated by the polarizable continuum model (PCM). Analysis of the results shows that there are relevant differences in the reaction pathways between the gas phase and with solvent. Only results in solvent phase are in accord with literature experimental results where 6-substituted 8-azabicyclo[3.2.1]oct-3-en-2-ones are formed preferentially. These polar cycloaddition reactions t…
QR-Factorization Algorithm for Computed Tomography (CT): Comparison With FDK and Conjugate Gradient (CG) Algorithms
2018
[EN] Even though QR-factorization of the system matrix for tomographic devices has been already used for medical imaging, to date, no satisfactory solution has been found for solving large linear systems, such as those used in computed tomography (CT) (in the order of 106 equations). In CT, the Feldkamp, Davis, and Kress back projection algorithm (FDK) and iterative methods like conjugate gradient (CG) are the standard methods used for image reconstruction. As the image reconstruction problem can be modeled by a large linear system of equations, QR-factorization of the system matrix could be used to solve this system. Current advances in computer science enable the use of direct methods for…
Understanding the [2n+2n] reaction mechanism between a carbenoid intermediate and CO2
2016
ABSTRACTThe mechanism of the cycloaddition reaction of CO2 with a nucleophilic carbenoid intermediate has been theoretically studied by using the bonding evolution theory (BET) at the B3LYP/6-31G(d) level of theory. BET combines topological analysis of the electron localisation function and catastrophe theory along a reaction path. This cycloaddition reaction is characterised by 16 structural stability domains, associated to the following sequence of catastrophes: C8H9NO4 + CO2: 16-CF†CF†F†CFF†C†C†[FF†]F†FCC†-0: C9H9NO6. Formation of the two new C-C and C-O single bonds evolves after the transition state structure is reached. The high nucleophilic character and the electronic structure of c…
Resist Coating of Cylindrical Samples for 3‐D Lithography
1995
A quantitative investigation of a dipping technique for depositing a thin layer of resist on circularly symmetrical objects is presented. The results obtained are valuable for preparing three-dimensional (3-D) surfaces suited for spatial microlithographic processes in the 1 to 10 μm linewidth range. © 1995, MCB UP Limited
Chronic lymphocytic leukemia nurse-like cells express hepatocyte growth factor receptor (c-MET) and indoleamine 2,3-dioxygenase and display features …
2014
Hepatocyte growth factor, produced by stromal and follicular dendritic cells, and present at high concentrations in the sera of patients with chronic lymphocytic leukemia, prolongs the survival of leukemic B cells by interacting with their receptor, c-MET. It is, however, unknown whether hepatocyte growth factor influences microenvironmental cells, such as nurse-like cells, which deliver survival signals to the leukemic clone. We evaluated the expression of c-MET on nurse-like cells and monocytes from patients with chronic lymphocytic leukemia and searched for phenotypic/functional features supposed to be influenced by the hepatocyte growth factor/c-MET interaction. c-MET is expressed at hi…
Bis (μ-tetrazolato-NN′) bridged dinuclear nickel(II) Schiff base complexes: Tandem synthesis, structure and self assembly
2015
Abstract Two new bis(μ-tetrazolato-NN′) bridged dinuclear nickel(II) Schiff base complexes [Ni2L12(PTZ)2]·2(CH3)2SO·2.69H2O (1) and 2[Ni2L22(PTZ)2]·3H2O (2) (HL1 and HL2 are Schiff bases, HL1 = 2-((2-(dimethylamino)ethylimino)methyl)phenol, HL2 = 2-((2-(methylamino)ethylimino)methyl)-6-methoxyphenol and HPTZ is 5-pyrazinyltetrazole) have been synthesized via [3+2] cyclo-addition of 2-cyanopyrazine and sodium azide in presence of nickel(II) acetate tetrahydrate and the respective Schiff bases. The structures of the complexes are confirmed by single crystal X-ray diffraction analysis. Both complexes show fluorescence. The change in the denticity of the Schiff base blocking ligand is shown to …
Drawings, Gestures and Discourses: A Case Study with Kindergarten Students Discovering Lego Bricks
2020
This paper presents a study aimed at investigating the didactic potentiality of the use of an artefact, useful to construct mathematical meanings concerning the coordination of different points of view, in the observation of a real object/toy. In our view, the process of meaning construction can be fostered by the use of adequate artefacts, but it requires a teaching/learning model, which explicitly takes care of the evolution of meanings, from those personal, emerging through the activities, to the mathematical ones, aims of the teaching intervention. The main hypothesis of this study is that the alternation between different semiotic systems, graphical system, verbal system and system of …
Gathering of aging and estrogen withdrawal in vascular dysfunction of senescent accelerated mice.
2010
The aim of this work was to characterize a mouse model of experimental menopause and cardiovascular aging that closely reflects menopause in women. Senescence accelerated mouse (SAM)-Resistant type 1 (SAMR1, n=30) and SAM-Prone type 8 (SAMP8, n=30) were separated at 5months of age into three groups: 1) sham-operated (Sham); 2) ovariectomized (Ovx); and 3) ovariectomized chronically-treated with estrogen (Ovx+E2). Contractile responses to KCl (60mM) and thromboxane A(2) were greater in aorta from SAMP8 mice compared with SAMR1 in all groups. Neither ovariectomy nor estrogen replacement modified the contractile responses from SAMR1 mice. Conversely, in Ovx SAMP8 the increased maximal contract…