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Dive into the research topics where M. Della Monica is active.

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Featured researches published by M. Della Monica.


Materials Science and Engineering: C | 2002

Development of a novel enzyme/semiconductor nanoparticles system for biosensor application

M. L. Curri; Angela Agostiano; G. Leo; Antonia Mallardi; Pinalysa Cosma; M. Della Monica

Abstract Nanosized semiconductor crystals can increase efficiency of photochemical reactions and can be effectively coupled to biomolecular units, such as enzyme, to generate novel photoelectrochemical systems. In this work, nanocrystalline CdS has been synthesized by using a microemulsive system and immobilised by self-assembling on a gold electrode in order to prepare, combined with formaldehyde dehydrogenase (FDH) enzyme, a biological-inorganic hybrid able to perform catalytic oxidation of formaldehyde. The preliminary results indicate that quantum-sized CdS layer on gold, in close contact with the enzyme, is an effective photoactive material to replace the NAD+/NADH role as charge transfer in the enzymatic reaction.


Synthetic Metals | 2003

High quality CdS nanocrystals: surface effects

F. Zezza; Roberto Comparelli; Marinella Striccoli; M. L. Curri; Raffaele Tommasi; Angela Agostiano; M. Della Monica

Stable and highly luminescent CdS nanocrystals (NCs) have been synthesized by means of decomposition of suitable precursors (CdO and elemental sulphur) in octadecene (ODE) and oleic acid at high temperature. Absorption and steady state photoluminescence (PL) measurements have been carried out to study the intrinsic properties of nanocrystals and the effect of ligand and solvent on emission properties. Ageing of nanocrystals has been investigated, and an efficient mechanism of emission recovery has been identified, showing the active role of non coordinating solvent and oleic acid in modifying the surface states.


Inorganica Chimica Acta | 1968

Silver complexes with I−, Br− and SCN− in sulfolane

M. Della Monica; Ugo Lamanna; L. Senatore

Abstract The solubility product constants of silver bromide(I), iodide(II), and thiocyanate(III) and the over-all formation constants β of AgnXm(m−n)− (X = Br, I, SCN) complexes in sulfolane at 30°, have been calculated from potentiometric titrations. At ionic strength μ = 0.1 the stoichiometric solubility product constants were: 6.6 × 10−19 (I), 3.3 × 10−19 (II), 5.4 × 10−17 (III). In the range of complexing agent concentrations explored, only one complex has been found for Br− (AgBr2−, β = 2.1 × 1019, only one complex for I− (Ag3I(4−, β = 3.3 × 1056) and only one complex for SCN− (Ag(SCN)2−, β = 1.1 × 1016). The above formulas of the complex ions have been also confirmed by conductometric titrations.


Bioelectrochemistry and Bioenergetics | 1990

Spectroscopic and electrochemical characterization of chlorophyll a in different water + organic solvent mixtures

Angela Agostiano; Pinalysa Cosma; M. Della Monica

Abstract Triangular-sweep adsorption voltammetry and absorption and fluorescence spectroscopy are employed in the study of chlorophyll a hydration and aggregation in binary mixtures of water with acetone, dimethylformamide (DMF) and acetonitrile (ACN). From the variation of the relative intensities and positions of the polarographic and spectroscopic peaks with the composition of the solvent, it is concluded that the organic solvates of Chl a are completely converted to Chl a·2 H2O at a water mole fraction χH2O ⪢ 0.66. A further shift in the equilibrium towards the dimerization of Chl a·2 H2O is observed at χH2O ⪢ 0.75. The lower water content and Chl a concentration required for aggregation in DMF and ACN compared with that required in acetone is discussed in terms of the bulk properties of the binary solvent mixtures.


Electrochimica Acta | 1975

Density, viscosity and electrical conductivity of LiCl and some uni-bivalent electrolytes in formamide solutions at 25°C

P. Bruno; M. Della Monica

Abstract Density, viscosity and equivalent conductivity in formamide at 25°C are reported for LiCl, Mg(ClO 4 ) 2 , CaCl 2 , CaBr 2 , Ca(NO 3 ) 2 , ZnCl 2 , ZnBr 2 and ZnI 2 salts. The linear dependence of the density of the investigated salts on the concentration is interpreted assuming that the structural configuration of the solvent formamide remains unchanged in the concentration range experienced. Viscosity and conductivity data have been treated following a proposal of Angell. A least-squares program used to linearise the lg Λ and the lg η functions against 1/( N 0 − N ) gives N 0 values, the glass-transition concentration at 25°C, acceptably low and sufficiently close in most cases.


Materials Science and Engineering: C | 2002

Reverse micellar systems: self organised assembly as effective route for the synthesis of colloidal semiconductor nanocrystals

M. L. Curri; Angela Agostiano; Fabio Mavelli; M. Della Monica

Nanoparticles can be obtained by using self-assembly molecules as a template, exploiting confined growth inside the surfactant film of microemulsion system. In this work, the feasibility of using quaternary water-in-oil microemulsion (CTAB/hexane/pentanol/water) to synthesise nanometer-sized structures of semiconductor material (CdS) with desired size distribution is described. Stochastic kinetic simulations have been utilised to account for the observed template effect of the microemulsion aggregate size on the nanocluster growth.


Journal of Electroanalytical Chemistry | 1976

A polarographic investigation on the equilibrium constants of crown complexes in alcoholic solutions

Angela Agostiano; M. Caselli; M. Della Monica

Abstract The complexation constants of sodium, potassium, and cesium salts with crown compounds have been measured polarographically in methanol, ethanol, and n-propanol. For each ion the equilibrium constant increases with the decreasing polarity of the solvent. In all solvents the constant relative to K+ ion presents the greatest value. The results are discussed taking into account the solvation energy of the ions in different solvents; the ratio between the ionic radius and the radius of the cavity of the complexing agent; and the interaction between the ion and the dipole groups of the ligand.


Biophysical Chemistry | 1996

CHLOROPHYLL A SELF-ORGANIZATION IN MICROHETEROGENEOUS SURFACTANT SYSTEMS

Angela Agostiano; Lucia Catucci; Giuseppe Colafemmina; M. Della Monica

Abstract Study on the factors affecting the chlorophyll a (Chl a) organization with neutral, positively and negatively charged surfactants has been performed by using UV-Vis absorption spectroscopy and circular dichroism. NMR techniques have been employed to investigate the role played in the surfactant reorganization by the state of aggregation of the Chl a host. Micelles and lamellar phases have been used during the investigation, carried out at different surfactant and pigment concentrations. Ionic surfactants in micellar phases always promote the Chl a aggregation. By varying the non-ionic surfactant concentration, it is possible to modulate the amounts of the aggregated and monomeric forms of Chl a. The pigment accelerates the lamellar phase formation and influences the phase organization only above a surfactant concentration of 30%.


Biophysical Chemistry | 1993

Chlorophyll a auto-aggregation in water rich region

Angela Agostiano; M. Della Monica; Gerardo Palazzo; M. Trotta

Abstract Visible absorption and fluorescence spectroscopy, togheter with circular dichroism were employed to investigate the equilibrating chlorophyll a species formed in solution at different water/ acetonitrile content and different pigment concentrations. Changes in chlorophyll a auto-aggregation occurring in water containing acetonitrile in the range 0.1–33% (v/v) were observed and related to the bulk properties of the medium. A 713 nm absorbing species, occurring in solution for water concentrations exceeding 99% was characterized. The influence of the ionic strength of the solution was also subject of the present study, together with the time evolution of the different aggregates.


Electrochimica Acta | 1984

A conductivity equation for concentrated aqueous solutions

M. Della Monica; A. Ceglie; Angela Agostiano

Abstract The effect of the viscosity medium change on the electrophoretic term of the conductivity equation has been evaluated for concentrated NaCl, NaClO 4 , NaNO 3 , NH 4 Cl and NH 4 NO 3 aqueous solutions. For NaCl and NH 4 Cl systems a good agreement between the experimental results and the ones obtained through a proposed equation was obtained. In the case of NaNO 3 systems, where an appreciable association to ion pairs was found, the dissociation degree of the electrolytes, α, and the thermodynamic association constant of the NH 4 NO 3 system were also calculated. The results of the NaClO 4 -water system seem to confirm a previous hypothesis on the anomalous conductance of the ClO − 4 ions in the field of high concentrations.

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