656 research outputs found
The manufacture and products thereof of photo-sensitizing nanomaterials and their use in photodynamic treatments
A method for the manufacture of a photosensitizing nanoma
terial (40) and the products thereof are disclosed. The method
for the treatment of a biological target (50) is disclosed. The
photosensitizing nanomaterial (40) comprises a metal com
plex tetrapyrrole derivative (10). The metal complex tetrapy
rrole derivative (10) is attached by an axial covalent bond (60)
to the surface (25) of a solid nanomaterial (20). The solid
nanomaterial (20) has at least one dimension in the nanometer and/ or the micrometer range
The application of the Boolean Stochastic Generation Method to model seepage under levees in heterogeneous soils
Soil heterogeneity plays an important role in incrementing the uncertainty about the reliability of geotechnical engineering works, especially levees. The presence of thin layers of soils more permeable than the surrounding matrix significantly changes the seepage flow net below and within the dike. However, the detection of these layers is extremely difficult. Consequently, to evaluate the overall safety of dikes it may be useful to adopt stochastic computation methods. The paper presents the calibration of a seepage model of an operational river embankment subject to sand boils. The levee, located along the Adige River (South Tyrol, Italy), has been monitored since 2016. Piezometers and spot temperature sensors are installed in the lateral banks while a distributed fiber optic sensors (FOS), buried in a 350 m long trench at the toe of the levee, is used to check temperature distribution in the subground. The Boolean Stochastic Generation (BoSG) method addresses the influence of layers of material with different properties with respect of the surrounding soil. 360 soil configurations were generated for a two-dimensional groundwater flow model of the levee and confronted with the monitoring data of two piezometers. This analysis permits to identify the configuration that has effects more congruent with piezometers data, which in this case is a configuration with a major presence of lenses on the waterside respect the field-side. This evidence could guide strategies for remedial works
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A novel heteroditopic terpyridine-pincer ligand as building block for mono- and heterometallic Pd(II) and Ru(II) complexes
A palladium-catalyzed Stille coupling reaction was employed as a versatile method for the synthesis of a novel terpyridine-pincer (3, TPBr) bridging ligand, 4'-{4-BrC6H2(CH2NMe2)(2)-3,5}-2,2':6',2 ''-terpyridine. Mononuclear species [PdX(TP)] (X = Br, Cl), [Ru(TPBr)(tpy)](PF6)(2), and [Ru(TPBr)(2)](PF6)(2), synthesized by selective metalation of the NCNBr-pincer moiety or complexation of the terpyridine of the bifunctional ligand TPBr, were used as building blocks for the preparation of heterodi- and trimetallic complexes [Ru(TPPdCl)(tpy)](PF6)(2) (7) and [Ru(TPPdCl)(2)]-(PF6)(2) (8). The molecular structures in the solid state of [PdBr(TP)] (4a) and [Ru(TPBr)(2)](PF6)(2) (6) have been determined by single-crystal X-ray analysis. Electrochemical behavior and photophysical properties of the mono-and heterometallic complexes are described. All the above di- and trimetallic Ru complexes exhibit absorption bands attributable to (MLCT)-M-1 (Ru -> tpy) transitions. For the heteroleptic complexes, the transitions involving the unsubstituted tpy ligand are at a lower energy than the tpy moiety of the TPBr ligand. The absorption bands observed in the electronic spectra for TPBr and [PdCl(TP)] have been assigned with the aid of TD-DFT calculations. All complexes display weak emission both at room temperature and in a butyronitrile glass at 77 K. The considerable red shift of the emission maxima relative to the signal of the reference compound [Ru(tpy)(2)](2+) indicates stabilization of the luminescent (MLCT)-M-3 state. For the mono- and heterometallic complexes, electrochemical and spectroscopic studies (electronic absorption and emission spectra and luminescence lifetimes recorded at room temperature and 77 K in nitrile solvents), together with the information gained from IR spectroelectrochemical studies of the dimetallic complex [Ru(TPPdSCN)(tpy)](PF6)(2), are indicative of charge redistribution through the bridging ligand TPBr. The results are in line with a weak coupling between the {Ru(tpy)(2)} chromophoric unit and the (non)metalated NCN-pincer moiety
Custo da implantação de sistemas de produção silvipastoris em São Carlos, SP.
Produção pecuária tradicional gerou um grande passivo ambiental. As preocupações recentes com qualidade da carne, bem-estar animal e proteção ambiental estão perfeitamente sintonizadas com sistemas de produção de base ecológica, como sistemas agroflorestais, e neste caso, com uma de suas modalidades, sistemas silvipastoris. Este trabalho tem por objetivo avaliar o custo de implantação de sistemas silvipastoris com espécies florestais nativas. Uma área de 11,7 ha formada com pastagens degradadas foi plantada com sete espécies florestais nativas em renques com três linhas de árvores espaçados de 15 m. O sistema 1 consiste da produção animal nas entrelinhas (integração pecuária-floresta) e o sistema 2 inlcui o cultivo agrícola nas entrelinhas com o objetivo de alimentação animal na seca (integração lavoura-pecuária-floresta). O custo total de implantação do sistema1 foi de R4.446,72/ha
Diversidade de espécies de aves em silvicultura de eucalipto.
Com a rápida e crescente expansão da silvicultura, especialmente no Estado de São Paulo, é comum o debate sobre os impactos e possíveis benefícios de tal prática, principalmente sobre a biodiversidade. Entretanto, levantamentos de indicadores de biodiversidade nessas áreas ainda são escassos e existe uma grande lacuna de conhecimento. Este trabalho apresenta resultados sobre a caracterização da avifauna encontrada em uma propriedade de silvicultura de Eucalyptus no Município de Brotas, SP. A amostragem da avifauna foi realizada usando a metodologia de contagem por pontos. Após seis campanhas de campo foram registradas 53 espécies de aves para a área de estudo, distribuídas em 23 famílias e 11 ordens. A ordem dos Passeriformes foi a que apresentou maior número de espécies (34) e de contatos (132). De acordo com a análise da frequência de ocorrência, poucas espécies mostraram-se frequentes na região e outras apareceram em um único ponto, fato que poderia ser indicativo de grande variedade de nichos ecológicos. Análises futuras avaliarão a diversidade da fauna em relação a indicadores de ecologia da paisagem e em relação à fitossociologia do sub-bosque nas áreas de cultivo de eucalipto.bitstream/item/56791/1/015-11.pd
Glyco-functionalized dinuclear rhenium(i) complexes for cell imaging
The design, synthesis and photophysical characterization of four new luminescent glycosylated luminophores
based on dinuclear rhenium complexes, namely Glyco-Re, are described. The derivatives have the
general formula [Re2(\u3bc-Cl)2(CO)6(\u3bc-pydz-R)] (R-pydz = functionalized 1,2-pyridazine), where a sugar
residue (R) is covalently bound to the pyridazine ligand in the \u3b2 position. Different synthetic pathways have
been investigated including the so-called neo-glycorandomization procedure, affording stereoselectively
glyco-conjugates containing glucose and maltose in a \u3b2 anomeric configuration. A multivalent dinuclear
rhenium glycodendron bearing three glucose units is also synthesized. All the Glyco-Re conjugates are
comprehensively characterized and their photophysical properties and cellular internalization experiments
on human cervical adenocarcinoma (HeLa) cells are reported. The results show that such Glyco-Re
complexes display interesting bio-imaging properties, i.e. high cell permeability, organelle selectivity, low
cytotoxicity and fast internalization. These findings make the presented Glyco-Re derivatives efficient
phosphorescent probes suitable for cell imaging applicatio
Rhenium complex as emitting material in highly efficient phosphorescent organic light-emitting diodes
Interest in luminescent materials able to efficiently emit in the solid state is continuously
growing, because in most applications the dyes are used as solid films. This is the case of the
Organic Light Emitting Diodes (OLEDs), where electroluminescent
metal complexes have been widely investigated as dopants, able to
increase their performances [1]. We present here a dinuclear Re(I)
complexes (1, see Scheme 1) whose emission is higher in solid state
and in PMMA matrix than in solution and is used as dopant in
OLEDs.
This complex belong to the family of neutral Re(I) complexes
with general formula [Re2(CO)6(\u3bc-1,2-diazine)(\u3bc-X)2], where X is halogen. Some of them
have recently gained interest for their intense yellow/green emission, occurring from triplet
metal-to-ligand charge transfer (3MLCT) states [2], showing a modulation effect of the
diazine substituents on wavelengths, lifetimes and quantum yields of the emission. \u3a6 up to
0.53 has been measured for the di-chloro complexes containing diazines bearing alkyl groups
in both the \u3b2 positions [3]. At variance with the chloro derivatives, the bromo analogue 1 is
almost not-emitting in solution (\u3a6em 0.002 in deareated toluene). We have now found that in
the solid state 1 shows intense yellow-orange emission (\u3a6em 0.50 in neat powder), blue
shifted with respect to the solution (560 nm vs. 620 nm). The emission is intense also in
PMMA matrix (\u3a6em 0.19 in PMMA at 10% w/w, 556 nm).
This very high aggregated emission here is discussed in terms of the restriction of the
intramolecular roto-vibrational motions of the \u201cRe2(CO)6(\u3bc-Br)2\u201d scaffold imposed by the
rigid environment, as evidenced by the strong decrease of the knr. Moreover a parallel increase
of kr is noticed, which clearly shows the influence of the halides in determining not only the
energy of the excited state, but also the nature of the lowest (emitting) state.
These properties allowed its successful use as a phosphorescent dopant in OLEDs and
here we report the performances of OLED devices prepared both by solution- and vacuumprocessing.
The values of the external quantum efficiency are 1.7% (4.3 cd/A and 1.7 lm/W)
and 10% (29.1 cd/A and 22.1 lm/W) respectively and are the highest ever reported for
rhenium-based devices, comparable to state-of-the-art devices employing Ir(III)- and Pt(II)-
based metal complexes. The combination of synthetic strategy and encouraging results in
potential OLEDs applications should make these dinuclear Re(I) complexes highly attractive
to a broad spectrum of research fields.
1. \u201cHighly efficient OLEDs with Phosphorescent Materials\u201d H. Yersin Ed. Wiley-VCH, (2008).
2. D. Donghi, G. D\u2019Alfonso, M. Mauro, M. Panigati, P. Mercandelli, A. Sironi, P. Mussini, L. D\u2019Alfonso, Inorg.
Chem. 28 (2008) 4243-4255.
3. M. Mauro, E. Quartapelle Procopio, Y. Sun, C. H. Chien, D. Donghi, M. Panigati, P. Mercandelli, P. Mussini,
G. D\u2019Alfonso, L. De Cola, Adv. Funct. Mater. 19 (2009) 2607-2614
Solvent-Driven Supramolecular Wrapping of Self-Assembled Structures
Self-assembly relies on the ability of smaller and discrete entities to spontaneously arrange into more organized systems by means of the structure-encoded information. Herein, we show that the design of the media can play a role even more important than the chemical design. The media not only determines the self-assembly pathway at a single-component level, but in a very narrow solvent composition, a supramolecular homo-aggregate can be non-covalently wrapped by a second component that possesses a different crystal lattice. Such a process has been followed in real time by confocal microscopy thanks to the different emission colors of the aggregates formed by two isolated PtII complexes. This coating is reversible and controlled by the media composition. Single-crystal X-ray diffraction and molecular simulations based on coarse-grained (CG) models allowed the understanding of the properties displayed by the different aggregates. Such findings could result in a new method to construct hierarchical supramolecular structures
Amino grafted MCM-41 as highly efficient and reversible ecofriendly adsorbent material for the Direct Blue removal from wastewater
The very high adsorption efficiency of Direct Blue (DB), an anionic toxic azo dye, onto amino grafted mesoporous
silica nanoparticles (MCM-41), was studied in this paper, for possible industrial applications. Interesting challenges and advances are proposed in this field, presenting an adsorbent able to efficiently and rapidly remove the anionic dye from water. The important added value of this work regards the system recycle, which allows both the DB and adsorbent material recover, with a global reduction of the environmental impact, in the viewpoint of the green economy. Indeed, this paper is the first example of very fast removal and recycle of great
amounts of DB with adsorbent materials characterized by impressive adsorption/desorption capacities, at least
of around 300mg/g for each adsorption cycle, potentially increasable by performing consecutive cycles of DB adsorption/desorption. In detail, the MCM-41 amino functionalization (MCM-41-NH2) was obtained after (MCM-
41-POST) and during (MCM-41-PRE) the synthesis of MCM-41, obtaining materials with different behavior towards
the DB adsorption. The MCM-41-NH2 surface features and porous structure, before and after the dye adsorption,
were carefully characterized. Considering the adsorption process, for investigating the nature of the DB/MCM-41-NH2 interaction, several parameters were studied: the contact time, the DB solutions pH values, adsorbent material and dye amount, with the additional analysis of how the adsorption process was influenced by the presence of electrolytes. The isotherms of adsorption were also considered. Although MCM-41-PRE exhibited
a higher affinity towards DB molecules, the MCM-41-POST were able to rapidly desorb it, thus recycling both DB
and the adsorbent material
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