Search results for " zinc"
showing 10 items of 77 documents
Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites in the Axis
2010
A new example of a linear [5]rotaxane has been synthesized by using the traditional "gathering-and-threading" approach but based on an unusual axle incorporating a symmetrical bis(bidentate) chelating fragment built on a 4,7-phenanthroline core. The stoppering reaction is particularly noteworthy since, instead of using a trivial bulky stopper as precursor to the blocking group, two semistoppered copper-complexed [2]pseudorotaxanes (namely [2]semirotaxanes) are used, which leads to the desired [5]rotaxane in good yield. The efficiency of the method relies on the use of "click" chemistry, with its very mild conditions, and on the protection by a transition-metal (copper(I)) of the various coo…
Hard X-Ray Response of Pixellated CdZnTe Detectors
2009
In recent years, the development of cadmium zinc telluride (CdZnTe) detectors for x-ray and gamma ray spectrometry has grown rapidly. The good room temperature performance and the high spatial resolution of pixellated CdZnTe detectors make them very attractive in space-borne x-ray astronomy, mainly as focal plane detectors for the new generation of hard x-ray focusing telescopes. In this work, we investigated on the spectroscopic performance of two pixellated CdZnTe detectors coupled with a custom low noise and low power readout application specific integrated circuit (ASIC). The detectors (10x10x1 and 10x10x2 mm3 single crystals) have an anode layout based on an array of 256 pixels with a …
Fluorescence Quenching in Hybrid Solar Cells Based on Electrodeposited ZnO
2013
A study about fluorescence phenomena in hybrid donor-acceptor interfaces based on electrodeposited zinc oxide (e-ZnO) having different architectures is performed. In particular ITO/ZnO/P3HT and ITO/ZnO/P3HT:PCBM are investigated and their photoluminescence responses are compared with those of ITO/P3HT and ITO/P3HT:PCBM. As expected, ITO/ZnO/P3HT:PCBM and ITO/P3HT:PCBM present higher exciton quenching than ITO/ZnO/P3HT and ITO/P3HT respectively. Furthermore, the hybrid configuration ITO/ZnO/P3HT:PCBM displays a higher quenching percentage in a wider wavelength range than ITO/P3HT:PCBM, indicating a better photo-induced charge separation in e-ZnO based hybrid devices.
Metal ions modulate thermal aggregation of betalactoglobulin: a join chemical and physical characterization
2014
Abstract Molecular basis of the role played by Cu 2 + and Zn 2 + ions during the thermal aggregation processes of beta-lactoglobulin (BLG) was studied by using a joint application of different techniques. In particular, Raman spectroscopy was very useful in identifying the different effects caused by the two metals at molecular level (i.e. changes in His protonation state, disulfides bridge conformation, and micro-environment of aromatic residues), evidencing the primary importance of the protein charge distribution during the aggregation process. Both metal ions are able to act on this factor and favor the protein aggregation, but Zn 2 + is able to alter the natural conformational state of…
Crecimiento cristalino de nano y microestructuras de ZnO mediante PVD y MOCVD
2014
El tema central de esta tesis doctoral ha sido el crecimiento cristalino de nano y microestructuras de ZnO mediantes los métodos PVD y MOCVD. De manera general, mediante los diversos estudios realizados, hemos profundizado en el proceso de crecimiento de las nano y microestructuras de ZnO obtenidas con el método PVD en ausencia de catalizador dentro de un rango de temperaturas relativamente bajo (300-500 ºC). Los estudios realizados nos permitieron obtener la síntesis de una amplia gama de estructuras de ZnO con diferentes morfologías, como por ejemplo: poliedros aislados, agujas, hilos y capas rugosas. Adicionalmente, estos estudios nos han permitido mostrar que las características morfoló…
Inflammation, genes and zinc in Alzheimer's disease.
2007
Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western society mainly accounts for clinical dementia. AD has been linked to inflammation and metal biological pathway. Neuro-pathological hallmarks are senile plaques, resulting from the accumulation of several proteins and an inflammatory reaction around deposits of amyloid, a fibrillar protein, Abeta, product of cleavage of a much larger protein, the beta-amyloid precursor protein (APP) and neurofibrillary tangles. Amyloid deposition, due to the accumulation of Abeta peptide, is the main pathogenetic mechanism. Inflammation clearly occurs in pathologically vulnerable regions of AD and several i…
Experimental investigation on the efficiency of zinc(II) recovery from waste streams by TBP liquid-liquid extraction
2016
In many industrial processes the presence of zinc in the wastewater may represent an obstacle to its high efficient regeneration. This is the case of the treatment of spent pickling solutions aiming the recovery of hydrochloric acid via pyrohydrolysis techniques. Hydrochloric spent pickling solutions from steel processing contain relevant amount of metals such as iron (Fe) and zinc (Zn) that may significantly affect recovery of hydrochloric acid (HCl) through pyrohydrolysis. In fact, although Fe may be recovered as ferric oxide (Fe2O3) and does not have a substantial effect on pyrohydrolysis process, zinc chloride (ZnCl2) evaporating can occlude nozzles and stick to the pyrohydrolysis react…
Nanocompositi a base di polistirene e ossido di zinco: azione disperdente delle molecole POSS
2014
Density functional theory based screening of ternary alkali-transition metal borohydrides: a computational material design project.
2009
We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K M1; and 1 alkali, alkaline earth or 3d / 4d transition metal atom M2 plus two to five BH4 groups, i.e., M1M2BH42‐5, using a number of model structures with trigonal, tetrahedral, octahedral, and free coordination of the metal borohydride complexes. Of the over 700 investigated structures, about 20 were predicted to form potentially stable alloys with promising decomposition energies. The M1Al/ Mn/ FeBH44, Li/ NaZnBH43, and Na/ KNi/ CoBH43 alloys are …
Creixement cristal·lí mitjançant la tècnica MOCVD i caracterització morfològica i estructural dels òxids de cadmi i zinc
2019
L'òxid de cadmi (CdO) i l'òxid de zinc (ZnO) han estat postulats com dos materials amb gran potencialitat en un ampli ventall d'aplicacions tecnològiques. Pel que fa a les seues propietats físiques, ambdós presenten un caràcter semiconductor de tipus “n”, sense dopatge intencionat. A més, el seu bandgap directe a 2.2 i 3.3 eV, respectivament, asseguren un bon grau de transparència òptica en la regió infraroja i visible de l'espectre electromagnètic. La projecció d'aquests compostos en camps com la plasmònica o les tecnologies basades en transicions intersubbanda fa convenient el control per a l'obtenció de capes molt primes. Malgrat això, gairebé tots els treballs publicats reporten capes p…