Pedro david Gara

Pedro david Gara
Universidad Nacional de La Plata | UNLP · Centro de Investigaciones Opticas (CIOp)

biochemist

About

29
Publications
4,292
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490
Citations
Additional affiliations
July 2010 - present
Universidad Nacional de La Plata
Position
  • Researcher
July 2010 - present
Centro De Investigaciones Opticas Conicet
Position
  • Research Associate

Publications

Publications (29)
Article
The photochemical and photophysical properties of a Re(I) tricarbonyl complex, ClRe(CO)3(nHo)2, where nHo = 9H-pyrido[3,4-b] indole (norharmane), were investigated in solution phase by a combination of steady state emission spectroscopy, laser flash photolysis (LFP) and pulse radiolysis (PR) techniques. These results allowed us to identify and stud...
Article
Full-text available
Soil is the recipient of organic pollutants as a consequence of anthropogenic activities. Hydrocarbons are contaminants that pose a risk to human and environmental health. Bioremediation of aging contaminated soils is a challenge due to the low biodegradability of contaminants as a result of their interaction with the soil matrix. The aim of this w...
Article
Full-text available
Photothermal therapy (PTT) is a noninvasive treatment for cancer relying on the incorporation of NIR-light absorbing nanomaterials into cells, which upon illumination release heat causing thermally induced cell death. We prove that irradiation of aqueous suspensions of poly(vinylpyrrolidone)-coated silver nanoplates (PVPAgNP) or PVPAgNP in HeLa cel...
Article
Immobilization of PEG-covered Silicon Dots, PEGSiDs, on glass substrates was performed following a simple strategy involving particle embedding by a sol-gel process forming a silica film on glass slides. The obtained films, denoted as fSiOx-PEGSiD, constitute a water-wettable, strongly supported, photoluminescent glass coating. The films showed hig...
Article
Carminic acid (CA) and other related compounds have been widely used as dyes in cultural heritage, cosmetic and food industry. Therefore, the study of their properties upon photoexcitation is particularly important. In this work, the photophysical and photochemical properties of CA, Carminic Lake and other related pigments in aqueous solutions are...
Article
Magnetite‒Porous Silicon 100−150 nm size nanoparticles (MPSi) were obtained combining luminescent and magnetic properties from silicon and magnetite, respectively. MPSi hybrids were characterized by high-resolution transmission electron microscopy, atomic and magnetic force microscopy and X-ray photoelectron spectroscopy. The presence of magnetite...
Article
Re(I)‐polypyridyl complexes show quite interesting and distinctive photochemical and photosensitizing properties. This work describes the capability to induce (or photoinduce) DNA damage of three Re(I)‐complexes with a naturally occurring alkaloid called norharmane (nHo) as ligand: [Re(CO)3(nHo)(L)]CF3SO3 where L = 2,2´‐bipyridine (ReBpy), phenanth...
Article
In this work, we present a whole and deep study on the thermal redox and the photophysical and photochemical reactions of a tricarbonyl Re(I) complex coordinating Pterin, fac-ReI(CO)3(pterin)(H2O) (pterin = 2-amino-4-oxo-3H-pteridine). In aqueous solutions, the fluorescence of the complex is attributed to the emitting ¹IL state (τemi ∼ 7.6 ns). In...
Article
The impact of remediation combining chemical oxidation followed by biological treatment on soil matrix and microbial community was studied, of a chronically hydrocarbon contaminated soil sourced from a landfarming treatment. Oxidation by ammonium persulfate produced a significant elimination of polycyclic aromatic hydrocarbons (PAHs) and an increas...
Article
In the present work, we have synthesized and fully characterized the photophysical and photochemical properties of a selected group of N-methyl-β-carboline derivatives (9-methyl-β-carbolines and iodine salts of 2-methyl- and 2,9-dimethyl-β-carbolinium) in aqueous solutions, in the pH-range 4.0 - 14.5. Moreover, despite the quite extensive studies r...
Article
Laser flash-photolysis experiments (λexc = 355 nm) performed with aqueous solutions of Pony Lake and Waskish Peat fulvic acids at pH = 2 showed formation of transient species with absorption maxima at 470–480 nm with O2-independent lifetimes of 600–700 μs, which were assigned to a phenoxyl radicals. Formation of these radicals occurs after photoion...
Article
Steady state and time resolved luminescence experiments, calorimetric studies, as well as time-dependent density functional theory calculations performed on [ClRe(CO)3(Bathocuproinedisulfonate)]-2 show that the photophysical properties of the Re(I) anionic complex are determined by the balance between intraligand (1IL) and metal-ligand-to-ligand ch...
Article
Full-text available
The photophysical behavior of five acridine(1,8)dione dyes of biological interest was studied by absorption and fluorescence spectroscopy, photoacoustics and time resolved phosphorescence techniques. The results obtained in ethanol and acetonitrile solutions show that the main spectroscopic and photophysical parameters of these compounds depend str...
Article
Quantum yields and efficiencies of 1O2 (1Δ2) production along with photophysical properties for a number of Re(I) complexes in acetonitrile solutions are reported. Two different classes of Re(I) complexes, i.e. LS-CO2-Re(CO)3(bpy) (LS = 2-pyrazine, 2-naphthalene, 9-anthracene, 1-pyrene, 2-anthraquinone) and XRe(CO)3L (X=CF3SO3, py ; L = bpy, phen)...
Article
Full-text available
A group of nitrogen heterocyclic aromatic compounds used, among others, as UV-MALDI matrices was studied. By using spectroscopic, luminescence and photoacoustic techniques, as well as time resolved phosphorescence for singlet oxygen production determination, the behaviour of 9-aminoacridine (9AA), 3-aminoquinoline (3AQ), 2-(2-aminoethylamino)-5-nit...
Article
Full-text available
The capability of silicon nanoparticles to increase the yield of reactive species upon 4 MeV X-ray irradiation of aqueous suspensions and C6 glioma cell cultures was investigated. ROS generation was detected and quantified using several specific probes. The particles were characterized by FTIR, XPS, TEM, DLS, luminescence, and adsorption spectrosco...
Article
Full-text available
Photochemical processes in surface water induced by sunlight affect the redox chemistry of these waters. The humic substances (HS) are almost half of the dissolved organic carbon in natural waters and represent the main fraction of colored dissolved organic carbon that absorbs solar radiation. Upon UV-visible light absorption, the excited states of...
Article
The effect of molecular oxygen and water on the blue photoluminescence of silicon nanoparticles synthesized by anodic oxidation of silicon wafers and surface functionalized with 2-methyl 2-propenoic acid methyl ester is investigated. The particles of 3 +/- 1 nm diameter and a surface composition of Si(3)O(6)(C(5)O(2)H(8)) exhibit room-temperature l...
Article
The kinetics of the reaction of sulfate radicals with the IHSS Waskish peat fulvic acid in water was investigated in the temperature range from 289.2 to 305.2 K. The proposed mechanism considers the reversible binding of the sulfate radicals by the fulvic acid. The kinetic analysis of the data allows the determination of the thermodynamic parameter...
Article
The photodegradation of the herbicide clomazone in the presence of S(2)O(8) (2-) or of humic substances of different origin was investigated. A value of (9.4 +/- 0.4) x 10(8) m(-1) s(-1) was measured for the bimolecular rate constant for the reaction of sulfate radicals with clomazone in flash-photolysis experiments. Steady state photolysis of pero...
Article
By monitoring the decay of SO4*- after flash photolysis of aqueous solutions of S2O82- at different pH values, the kinetics of the reaction of SO4*- radicals with gallic acid and the gallate ion was investigated. The bimolecular rate constants for the reactions of the sulfate radicals with gallic acid and the gallate ion were found to be (6.3 +/- 0...
Article
Full-text available
To learn more about the role of the reactive oxygen species (ROS) in the production of bioavailable products of the dissolved organic matter, we investigate here the effect of the photolysis (lambda(exc) > 320 nm) of a soil extract (SE) on the growth of bacteria isolated from the same soil as used for obtaining the extract. Comparative experiments...
Article
The kinetics of the aqueous phase reaction of sulfate radicals with commercial humic acids and with organic matter extracted from vermicompost (VC) was studied by flash-photolysis. The results can be interpreted by a mechanism that in a first step considers the reversible binding of the sulfate radicals by the humic substances. Both the bound and f...
Article
Reactions of chlorine radicals might play a role in aqueous aerosols where a core of inorganic components containing insulators such as SiO2 and dissolved HUmic-LIke Substances (HULIS) are present. Herein, we report conventional flash photolysis experiments performed to investigate the aqueous phase reactions of silica nanoparticles (NP) and humic...
Article
Advanced oxidation processes, using either UVC/H2O2 or UVC/K2S2O8, both in the presence of H2CO2 or CH3OH are very efficient in mineralizing aqueous solutions of trichloroacetic acid (TCAA) leaving no toxic residues. The main reaction initiating TCAA depletion is its reduction by the radicals CO2- or CH2OH to yield CCl2CO2- radicals and Cl− anions....

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Project (1)
Project
Los invitamos a seguir las actualizaciones de de la Red AR-PAOS en ResearchGate: Red Argentina de Procesos Avanzados de Oxidación y de Reducción Ar-PAOs Ar-PAOs surge como una iniciativa que permita vincular a los diferentes grupos de investigación existentes en Argentina para compartir experiencias y saberes en las temáticas relacionadas a los procesos avanzados de oxidación, en conjunto con LATIN-AOPs.