1,721,046 research outputs found
The photodynamic inactivation of Staphylococcus aureus in water using visible light with a new expanded porphyrin.
No full textIn this work, the results of the application of organic expanded porphyrins in the disinfection of water
by the photodynamic inactivation (PDI) technique are presented. The photoinactivation properties of
a novel, expanded porphyrin, namely 20-(4-carboxyphenyl)-2,13-dimethyl-3,12-diethyl-(22π)
pentaphyrin (PCCox), were tested in the disinfection of water using Staphylococcus aureus as a
Gram-positive bacteria model. The data showed that PCCox was effective against S. aureus bacteria
at nanomolar concentrations. The variation with irradiation time and concentration was studied using
both a multi-LED monochromatic light (λ 1⁄4 470 nm) and an incandescent light bulb with a wide
emission spectrum. A PCCox dosage of 5 μM was sufficient to achieve a 99.997% abatement of
S. aureus within 1 h of 40 W/m2 irradiation with monochromatic light (λ 1⁄4 470 nm), whereas under
the same conditions using irradiation with white light, the abatement was 99.9997%
Spectroscopy characterization of the oxidation control of the iso-pentaphyrin/pentaphyrin system
No full textSelectivity and Efficiency of Conductive Molecularly Imprinted Polymer (c-MIP) Based on 5-Phenyl-Dipyrromethane and 5-Phenol-Dipyrromethane for Quorum Sensing Precursors Detection
No full textFunctional polymers that selectively recognize target compounds are developed by imprinting polymerization. In the present paper, two different dipyrromethanes, 5-phenol-dipyrromethane (5-pOH-DP) and 5-phenyl-dipyrromethane (5-ph-DP), are synthetized and investigated to develop conductive molecularly imprinted polymer (cMIP) sensors. As target molecules, two homoserine lactone derivatives were templated by an electrochemically driven polymerization process. Acyl-homoserine lactones (AHLs), also called homoserine lactones (HS), are a class of signaling molecules involved in bacterial quorum sensing (QS), which is a strategy of coordination among bacteria mediated by population density. The preparation of cMIP from 5-pOH-DP and 5-ph-DP in the presence of acetyl-homoserine lactone (Acetyl-HS) or carboxybenzyl-homoserine lactone (Cbz-HS) was performed by cyclic voltammetry (CV). The cMIP selectivity and sensitivity were assessed by microgravimetry (QCM). Both series of measurements were performed with the aid of an Electrochemical Quartz Crystal Microbalance (EQCM/QCM). The experimental evidences are discussed with respect to NMR measurements that were conducted to gain insight into the interactions established between monomers and templates. The NMR data interpretation offers preliminary information about the most probable positions involved in interaction development for both molecules and highlights the role of the hydration shell. The QCM-cMIP sensor was able to detect the analyte in the linear range from 10−8 mol·L−1 to 10−6 mol·L−1 and a limit of detection (LOD) of 22.3 ng (3σ of the blank signal) were evaluated. QCM rebinding tests demonstrated that cMIP selectivity was driven by the pendant group of dipyrromethane, which was also confirmed by the NMR data
“Synthesis and Characterization of a New Pentaphyrin Macrocycle as Potential Photosensitizer.”
No full textRIMOZIONE DEL MERCURIO DA FANGHI DI DRAGAGGIO MEDIANTE SCAMBIO IONICO E TRATTAMENTO TERMICO
No full textL’obiettivo di questa ricerca è sperimentare una tecnica per la bonifica di fanghi di dragaggio contaminati da mercurio. Si tratta di una tecnica “mista”, basata sul desorbimento termico a bassa temperatura associato allo scambio ionico. Teoricamente, la temperatura di estrazione del mercurio si può ridurre se esso viene prima fatto muovere, dalla matrice organica alla parte acquosa del fango. Uno dei possibili modi per muovere il mercurio, immobilizzato nel fango, verso la fase acquosa è sfruttare lo scambio ionico reversibile del catione inquinante. La strategia utilizzata in questo lavoro è quella di sfruttare lo scambio con un catione avente un’affinità maggiore per il sito di legame e/o presente in concentrazione maggiore rispetto all’inquinante. Sono state effettuate diverse prove di trattamento, utilizzando differenti sali in soluzione, in primo luogo dei cloruri (cloruro di calcio, tetrabutilammonio cloruro) con modeste efficienze di rimozione. Un sale, avente catione bivalente e massa molecolare simile a quella del tetrabutilammonio, si è dimostrato maggiormente efficiente per questo tipo di estrazione. I risultati ottenuti sono incoraggianti, in quanto dimostrano che la tecnica risulta efficace su una matrice reale, e quindi il desorbimento termico associato allo scambio ionico potrebbe essere un metodo percorribile per la bonifica di sedimenti contaminati da mercurio
Thermodynamic Studies on the Complexation of Cobalt(II) with Nitrogen Donor Ligands in Dimethylsulfoxide
No full textOxygenation reaction of Co(trien)(2+) complex in dimethylsulfoxide and the aerobic oxidation of 2,6-di-tert-butylphenol catalyzed by Co(II)-amine complexes
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