Search results for "travi"
showing 10 items of 1013 documents
A Bichromophore Based on Perylene and Terrylene for Energy Transfer Studies at the Single-Molecule Level
1999
A functionalized dialkylperylene and a modified terrylenetetracarboxdiimide (TTCDI) were joined by a hexanediyl spacer. The resulting bichromophoric molecule 1 (R = 4-tert-butylphenoxy) is a suitable model system for donor–acceptor energy transfer studies at the single-molecule level.
Synthesis and Electronic Spectra of Substitutedp-Distyrylbenzenes for the Use in Light-Emitting Diodes
2000
The influence of substitution on the absorption and Luminescence spectra of oligo(phenylenevinylene)s has been studied using distyrylbenzene (DSB) as a model compound. The degree, character, and pattern of substitution was varied systematically, altering the electronic properties of the DSB, the wavelength of the emitted light could be tuned over a range of 100 nm. The syntheses of 6b—h were performed by twofold Wittig Horner-olefinations of bisphoshonates 1a, b with substituted benzaldehydes 2a—i, 6ivia Heck-reaction of the dibromosulfonylbenzene 3, 6k by Siegrist-reaction of 4 with N-phenylbenzaldimine and the Knoevenagel-reaction of benzyl cyanide with 5 led to 6l.
[39] DNA damage induced by ultraviolet and visible light and its wavelength dependence
2000
Publisher Summary DNA damage induced by solar radiation in mammalian cells consists largely of two types of modification: pyrimidine dimers and oxidative modifications. Pyrimidine dimmers that can be subdivided into cyclobutane pyrimidine dimmers, (CPDs) and (6-4) photoproducts are the characteristic and most abundant modifications after direct excitation of DNA, although they can also be formed indirectly by energy transfer from other excited molecules such as carbonyl compounds. Oxidative DNA damage, which includes various pyrimidine and purine modifications, sites of base loss (AP sites), and strand breaks, is generated in only low yield after direct excitation of DNA (except at very sho…
Prove Sperimentali di Push-Out su Travi Reticolari Miste
2009
Nel presente lavoro sono descritte le prove di push-out realizzate sino ad oggi in tre diverse sedi Universitarie (Università del Salento, Università di Palermo, Università di Ferrara), operanti nel Gruppo di Ricerca finalizzato allo studio delle travi Prefabbricate Reticolari Miste, in collaborazione con le aziende di ASSOPREM. Dette prove hanno l’obiettivo di analizzare il comportamento all’interfaccia fra gli elementi resistenti nelle travi suddette, realizzate con traliccio prefabbricato e getto in opera di calcestruzzo. L’indagine condotta, sebbene ancora insufficiente a condurre a risultati di validità generale, evidenzia come al variare di alcuni parametri significativi si rilevi un …
A study of VUV emission and the extracted electron-ion ratio in hydrogen and deuterium plasmas of a filament-driven H−/D− ion source
2019
Vacuum ultraviolet (VUV) emission diagnostics for studying differences of electron impact processes in hydrogen and deuterium plasmas are presented. The method is applied to study a filament driven multicusp arc discharge negative ion source by comparing the VUV-emission intensities of different emission bands and extracted currents of H−/D− ions and electrons. It was found that the ratio of coextracted electrons to extracted ions is four times higher for deuterium than for hydrogen. No significant differences of the VUV-spectra or volumetric rates of ionization, excitation, production of high vibrational states, and dissociation were found between the plasmas of the two isotopes. The volum…
Sex and population variation in ultraviolet reflectance of colour patches in Gallotia galloti (Fam. Lacertidae) from Tenerife (Canary Islands)
2005
Sex and population differences in the ultraviolet (UV) reflectance patterns of two phenotypically divergent lacertids from Tenerife, Gallotia galloti eisentrauti and G. g. galloti, are described. Adults in both populations have rows of lateral and ventro-lateral blue patches on either side of the trunk that show a single peak of reflectance in the near UV. The lateral patches of males are more intensely reflective than those of females, but females have more chromatic and UV-shifted lateral patches than males. Most G. g. eisentrauti and some G. g. galloti also have blue cheek patches on either side of the gular area. Male cheek patches have reflectance peaks in the near UV, whereas those of…
A comparative study of the effect of UV and formalin inactivation on the stability and immunogenicity of a Coxsackievirus B1 vaccine
2019
Type B Coxsackieviruses (CVBs) belong to the enterovirus genus, and they cause both acute and chronic diseases in humans. CVB infections usually lead to flu-like symptoms but can also result in more serious diseases such as myocarditis, aseptic meningitis and life-threatening multi-organ infections in young infants. Thus, CVBs have long been considered as important targets of future vaccines. We have previously observed CVB1 capsid disintegration and virus concentration decrease with 12-day long formalin inactivation protocol. Here a scalable ion exchange chromatography purification method was developed, and purified CVB1 was inactivated with UV-C or formalin. Virus morphology and concentra…
Estudio del espesor óptico de nubes a partir de radiación solar
2015
El objetivo general de este trabajo es el cálculo del espesor óptico de nubes para nubes bajas y medias formadas por gotas de agua en la ciudad de Burjassot (Valencia), mediante un método de minimización. Los espesores han sido obtenidos tanto para cielos cubiertos como para cielos parcialmente nubosos con el Sol oculto por las nubes, a partir de medidas de irradiancia eritemática (UVER) e irradiancia solar total a nivel de suelo. Para ello se han utilizado dos modelos de transferencia radiativa que presuponen capas de nubes homogéneas plano-paralelas. También se han obtenido diferentes relaciones empíricas entre el espesor óptico de nubes obtenido y diferentes factores de transmisividad at…
Effect of air-absorbed oxygen and moisture on the chemical stability of photoexcitedMg,ZnandEuphthalocyanines in dimethylformamide
2006
Absorption of oxygen and moisture from air by MPc-DMF systems was studied and related to the molecular stability demonstrated by phthalocyanine complexes (unsubstituted MPc's : MgPc , ZnPc and EuPc2; Pc = phthalocyanine ligand, C32H16N8) subjected to UV irradiation. A lower stability of air-exposed dimethylformamide solutions is observed and is due to a specific affinity for molecular oxygen revealed by the Pc macrocycle. SEM results proved oxygen molecules fixed to the phthalocyanine solids by forces strong enough to sustain desorption under vacuum. Absorption curves determined for MPc-DMF systems also indicate oxygen accommodated by the phthalocyanine moiety. This explains the predominant…
Mixtures of lecithin with polymerizable derivatives of cholesterol. A monolayer film balance study.
1986
One of the best investigated binary lipid mixtures is the lecithin-cholesterol system. We show here that it is possible to modify the cholesterol in such a way that it can be polymerized without changing its behaviour in mixtures with lecithin. The polymerizable derivatives exhibit a very similar phase diagram in the mixture with dipalmitoyl-phosphatidylcholine as the cholesterol itself. This is demonstrated by filmbalance measurements.