Search results for "Nitro"
showing 10 items of 2762 documents
Generación de centros estereogénicos cuaternarios heterosustiruidos mediante las reacciones de Henry y aza-Henry
2015
La adición de nitroalcanos a compuestos carbonílicos o sus derivados nitrogenados (reacciones de Henry y aza-Henry, respectivamente) constituye una herramienta fundamental para la formación de enlaces C-C en química orgánica.[1] Los productos resultantes de estas reacciones son "building blocks" muy interesantes en síntesis orgánica ya que permiten el acceso a diferentes motivos estructurales gracias a la versatilidad química del grupo nitro [2] siendo de gran utilidad para la síntesis de fármacos y productos agroquímicos.[3] Además, en el transcurso de estas reacciones pueden formarse uno o más centros estereogénicos por lo que el control de la estereoquímica resulta crucial. Por este moti…
[1,2,3]Triazolo[1,5-a]piridinas y compuestos relacionados : aplicaciones en química supramolecular : actividad biológica
2013
Los heterociclos nitrogenados son moléculas clave dentro de numerosos campos científicos. En concreto, los triazoles han encontrado numerosas aplicaciones en química médica como antifúngicos (fluconazol, posaconazol), antidepresivos (trazodona) o anticancerígenos (triazoloacridonas). En este contexto se decidió sintetizar nuevos derivados de [1,2,3]triazolo[1,5-a]piridinas con el fin de explorar su capacidad de interaccionar con ADN y su actividad leishmanicida y antichagásica. Con este objetivo se ha utilizado la química clásica de las triazolopiridinas (reacción de litiación regioselectiva de este heterociclo, seguida de adición de un electrófilo), para obtener nuevos derivados con estruc…
Planting Date and Different N-Fertilization Rates Differently Modulate Agronomic and Economic Traits of a Sicilian Onion Landrace and of a Commercial…
2022
The onion is one of the most widespread bulb vegetables worldwide. Onion cultivation is common in Sicily, as is the use of local genotypes. Cultivation practices are of particular interest in optimizing yield, quality, and profits. The aim of this study was to assess the agronomic response of a Sicilian landrace (Bianca Calda di Comiso, coded L1) and a commercial variety (Bianca di Maggio, coded V1) to different planting dates and N fertilization rates. An economic appraisal was also performed. The two genotypes were assessed using an experimental split-split-plot design with four levels of nitrogen rates (0, 80, 160, and 220 kg N ha−1) and two different planting dates (8 October 2005…
A novel water-soluble BODIPY dye as red fluorescent probe for imaging hypoxic status of human cancer cells
2020
The development of effective methods for real-time monitoring of nitroreductase (NTR) activity is of great significance for medical diagnosis and cancer research. Here, we present a novel water-soluble BODIPY-based chemodosimeter (NBB) for imaging the hypoxic status of human non-small-cell lung cancer A549 cells. We assume that ‘on–off’ response of NBB is activated by the NTRmediated reductive release of meso-phenol BODIPY dye resulting in unusual fluorescence.
Abundance of narG , nirS , nirK , and nosZ Genes of Denitrifying Bacteria during Primary Successions of a Glacier Foreland
2006
ABSTRACT Quantitative PCR of denitrification genes encoding the nitrate, nitrite, and nitrous oxide reductases was used to study denitrifiers across a glacier foreland. Environmental samples collected at different distances from a receding glacier contained amounts of 16S rRNA target molecules ranging from 4.9 × 10 5 to 8.9 × 10 5 copies per nanogram of DNA but smaller amounts of narG , nirK , and nosZ target molecules. Thus, numbers of narG , nirK , nirS , and nosZ copies per nanogram of DNA ranged from 2.1 × 10 3 to 2.6 × 10 4 , 7.4 × 10 2 to 1.4 × 10 3 , 2.5 × 10 2 to 6.4 × 10 3 , and 1.2 × 10 3 to 5.5 × 10 3 , respectively. The densities of 16S rRNA genes per gram of soil increased with…
Contribution de l'agriculture à l'effet de serre. Importance de l'azote et interactions avec l'ozone
2008
Agriculture contributes to almost 20% of greenhouse gas emissions in France, and the same applies for most EU countries. This is due to a large extent to N2O emission after N fertilizer application, but the emissions are very variable in space and time, due mainly to the variability in environmental conditions. However, the figure of the relationship between agriculture and greenhouse effect is more complex. First a significant fraction of emitted N2O does not occur where N has been applied, but is due to indirect emissions in wetlands or forest where N is transferred by natural pathways. This implies the need to make an assessment at larger scale than the field where N is applied. Many oth…
Binding mode analysis of ABCA7 for the prediction of novel Alzheimer's disease therapeutics
2021
Graphical abstract
Carbon and nitrogen stable isotope ratios of soils and grasses as indicators of soil characteristics and biological taxa
2019
Abstract The use of stable isotope techniques can assist in understanding interactions of plants with various abiotic and biotic processes. In the research, we focused on carbon (C) and nitrogen (N) isotopes because they are the most important resources influencing plant function and the biogeochemical cycles. The 13C/12C and 15N/14N ratios in plants and in soils and the relationships between these ratios and biological and environmental factors of widely distributed native C3 plants (couch grass, plantain and yarrow) collected from two sites in St. Petersburg, Russia were studied. The soil characteristics of the sites were rather different. This had a significant effect on the isotope rati…
XAFS study of gadolinium and samarium bisporphyrinate complexes.
2001
The comparative X-ray absorption spectroscopy study of gadolinium and samarium bisporphyrinate complexes represented by the formulas Gd(III)H(oep)(tpp), Gd(III)(oep)(2), Gd(III)H(tpp)(2) and Sm(III)H(oep)(tpp), Sm(III)(oep)(2), Sm(III)H(tpp)(2) is reported. The XAFS spectra are recorded on the LURE-DCI storage ring (Orsay, France) in transmission mode on the microcrystalline samples at the Gd and Sm L(3) edges. The local environment for Ln(3+) ions has been reconstructed applying one-shell and two-shell XAFS analysis procedures. The protonated and nonprotonated bisporphyrinate complexes present different XAFS features. After our analysis on the title derivatives, the gadolinium ion (at 80 K…
Characterization of particle morphology of biochanin A molecularly imprinted polymers and their properties as a potential sorbent for solid-phase ext…
2014
Abstract Molecularly imprinted polymers (MIPs) with biochanin A as a template were obtained using a bulk polymerization with non-covalent imprinting approach. The polymers were prepared in acetonitrile as porogen, using ethylene glycol dimethacrylate (EDMA) as cross-linking agent. The synthesis, with an application of 1′,1′-azobis(cyclohexanecarbonitrile) (ACHN) as an initiator, has been performed thermally. During the synthesis process the effect of different functional monomers such as methacrylic acid (MAA), acrylamide (AA) and 4-vinylpyridine (4-VP) was investigated. The application of nitrogen sorption porosimetry, scanning electron microscopy (SEM), and Fourier transform infrared spec…