80 research outputs found
The role of copper (Ii) on kininogen binding to tropomyosin in the presence of a histidine–proline-rich peptide
The antiangiogenic activity of the H/P domain of histidine–proline-rich glycoprotein is mediated by its binding with tropomyosin, a protein exposed on endothelial cell-surface during the angiogenic switch, in presence of zinc ions. Although it is known that copper ion serum concentration is significantly increased in cancer patients, its role in the interaction of H/P domain with tropomyosin, has not yet been studied. In this paper, by using ELISA assay, we determined the modulating effect of TetraHPRG peptide, a sequence of 20 aa belonging to H/P domain, on the binding of Kininogen (HKa) with tropomyosin, both in absence and presence of copper and zinc ions. A potentiometric study was carried out to characterize the binding mode adopted by metal ions with TetraHPRG, showing the formation of complex species involving imidazole amide nitrogen atoms in metal binding. Moreover, circular dichroism showed a conformational modification of ternary systems formed by TetraHPRG, HKa and copper or zinc. Interestingly, slight pH variation influenced the HKa-TetraHPRG-tropomyosin binding. All these results indicate that both metal ions are crucial in the interaction between TetraHPRG, tropomyosin and HKa
Optical trapping of silver nanoplatelets
Optical trapping of silver nanoplatelets obtained with a simple room temperature chemical synthesis technique is reported. Trap spring constants are measured for platelets with different diameters to investigate the size-scaling behaviour. Experimental data are compared with models of optical forces based on the dipole approximation and on electromagnetic scattering within a T-matrix framework. Finally, we discuss applications of these nanoplatelets for surface-enhanced Raman spectroscopy
Determination of the size distribution of non-spherical nanoparticles by electric birefringence-based methods
The in situ determination of the size distribution of dispersed non-spherical nanoparticles is an essential
characterization tool for the investigation and use of colloidal suspensions. In this work, we test a size
characterization method based on the measurement of the transient behaviour of the birefringence
induced in the dispersions by pulsed electric fields. The specific shape of such relaxations depends on the
distribution of the rotational diffusion coefficient of the suspended particles. We analyse the measured
transient birefringence with three approaches: the stretched-exponential, Watson-Jennings, and multiexponential
methods. These are applied to six different types of rod-like and planar particles: PTFE
rods, goethite needles, single- and double-walled carbon nanotubes, sodium montmorillonite particles
and gibbsite platelets. The results are compared to electron microscopy and dynamic light scattering
measurements. The methods here considered provide good or excellent results in all cases, proving that
the analysis of the transient birefringence is a powerful tool to obtain complete size distributions of
non-spherical particles in suspension.Financial support of this investigation by Junta de AndalucĂa, Spain (grant No. PE2012-FQM0694) and University
of Granada (Program “Proyectos de investigación precompetitivos”) is gratefully acknowledged
Production and energy transformation of herbaceous biomasses irrigated with treated wastewater \u2013 first results
The first results on experiments with the goal of an agronomical, environmental, energetic and
economical evaluation about the biomass production from herbaceous species irrigated with treated wastewater are
reported in this paper. The experiments were conducted in collaboration with four Italian universities (within a
National Research Project, PRIN 2007): Padova, Bologna, Reggio Calabria and Catania. Six main herbaceous species
were tested by each university in their own experimental fields. In particular, each university planted four species
common to all units, one in the biggest plot and the others in three smaller plots. Physical, chemical and
microbiological analyses were carried out on wastewater samples. In particular, the following parameters were
evaluated: pH, electric conductivity, TSS, BOD5, COD, total phosphorus, ammonia, nitrite, nitrate and total nitrogen.
From an agronomic point of view, the growth dynamics, the translocations of assimilates between aerial and
subterranean organs, and the different species productivity were analysed. On the top part of the plants, the average
height, the biomass production, the moisture content at the harvesting and the heating values were measured
Produzione e caratterizzazione energetica di biomasse erbacee irrigate con acque reflue
The paper reports the results of the experimental activities carried out within a Nationa Research Project to evaluate the agronomic, envoronmental and energy sustainability of the biomass production by no-food crops irrigated with different kinds of treated wastewater. Four different research units monitored the same four main herbaceous species. physical and chemical analyses were carried out on wastewater samples. Bio-agronomical analysis on the species placed on fields were made with the goal to evaluate the main parameters sich as the productivity and the heating values. The analysis of the combustion efficiency, the amount of ash, and the environmental impact of the combustion residual was executed ina small boiler. The results highlight attractive biomass yield and an interesting crop energy capability by using treated wastewater for irrigation
Metamorfosi di cittĂ
Il volume, curato e in gran parte tradotto dalla sottoscritta, presenta per la prima volta in volume l'opera del poeta cipriota. La scelta dei testi ripercorre l’itinerario della sua poesia indagando sull’idea di patria del Poeta, come sentimento doloroso e opprimente, e dell’eterno viaggio in città che si trasformano l’una nell’altra, spesso sinonimo e metafora della figura femminile
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