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159 results on '"Saidman S"'

33. Corrosion protection properties of polypyrrole coatings formed onto 316 L SS from a solution containing molybdate and salicylate

Author

Ramos Camila A., González Maria B., Brugnoni Lorena I., and Saidman Silvana B.

Subjects
stainless steel, conducting polymer, microtubes, Chemistry, QD1-999
Abstract

The electrosynthesis of PPy films onto 316L stainless steel from nearly neutral and alkaline solutions containing molybdate and salicylate is reported. The corrosion behaviour of the coatings constituted by hollow rectangular microtubes was monitored in Ringer solution using open circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy. The polymer formed in a solution of pH 8 was the most efficient in terms of corrosion protection. The coating significantly reduced the pitting corrosion of the substrate. The results were interpreted taking into consideration the polymer electroactivity, the galvanic interaction polypyrrole/substrate and the nature of dopants. Silver species were effectively immobilized onto the hollow rectangular-sectioned microtubes of PPy. The modified coatings demonstrated that they have a good bactericidal activity against Escherichia coli and they were also able to protect the substrate against corrosion in Ringer solution.

Published
2022
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36. Removal of Escherichia coli from well water using continuous laminar flow in a channel system containing PPy/Cu modified electrodes.

Author

González, M. B., Brugnoni, L. I., Flamini, D. O., Quinzani, L. M., and Saidman, S. B.

Subjects
ESCHERICHIA coli, WELL water, LAMINAR flow, POLYPYRROLE, WATER disinfection, REYNOLDS number
Abstract

Polypyrrole (PPy) films modified with copper species were used for disinfection of well water contaminated with Escherichia coli (E. coli). For that purpose a laboratory-scale continuous flow system with a parallel plate flow chamber configuration was implemented operating under laminar flow. Three flow rates were considered. The testing conditions did not affect the morphology of the modified PPy films, even after 5 h of continuous use at the largest flow rate examined. The results show that the bacteria killing process can be described by a first-order kinetic law at all Reynolds numbers. As the flow rate increases, the concentration of Cu species released from the electrodes enhances, accelerating the disinfection process. Re-inoculation and Cu-recharging tests showed bactericidal effects very similar to those displayed by the freshly prepared electrodes. It is concluded that PPy/Cu-modified electrodes installed in the laboratory-scale continuous flow system are effective for the water disinfection process. [ABSTRACT FROM AUTHOR]

Published
2018
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37. Synthesis of a hole-containing polypyrrole film modified by copper cementation.

Author

Lehr, I. L. and Saidman, S. B.

Subjects
POLYMERS, ELECTROPOLYMERIZATION, SURFACE area, ELECTROCHEMICAL analysis, COPPER
Abstract

ABSTRACT A simple procedure enables to obtain a hole-containing PPy film on SAE 4140 steel in sodium bis(2-ethylhexyl) sulfosuccinate (AOT) solutions. The film characterization was made by electrochemical and morphological studies. The effects of electropolymerization parameters on the obtained morphology are discussed. The formation of the coating is conditioned by the nature of the substrate and surfactant and the electrochemical technique employed. Electrochemical investigations demonstrate that the hole-containing PPy film presents an increase in surface area. The polymer was modified by cementation of copper particles. The modified polymer offers a higher electrocatalytic activity for the HER than usual PPy. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43650. [ABSTRACT FROM AUTHOR]

Published
2016
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38. Corrosion protection of AZ91D magnesium alloy by a duplex coating

Author

Forero López Ana D., Loperena Ana P., Lehr Ivana L., Brugnoni Lorena I., and Saidman Silvana B.

Subjects
mg substrate, anticorrosion, electrodeposited polypyrrole, molybdate, salycilate, Chemistry, QD1-999
Abstract

A duplex coating was formed under potentiostatic conditions on magnesium alloy AZ91D in order to improve its corrosion resistance in a simulated physiological environment. The first layer was formed by anodization at low potentials in molybdate solution. The outer layer was a PPy film electrosynthesized in sodium salicylate solution. The conditions of the formation were determined to obtain a layer with globular morphology. The bilayer was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion protection properties of the coatings were examined in Ringer solution by monitoring the open circuit potential (OCP), polarization techniques, and electrochemical impedance spectroscopy (EIS). The obtained results showed that the bilayer improves the corrosion resistance of the substrate. Moreover, the duplex coating presented better anticorrosive properties than a single PPy film. Afterwards, the bilayer was modified by cementation of silver ions from a solution containing AgNO3. The modified electrode exhibited good antibacterial properties.

Published
2020
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39. Fluctuating lymphocyte chimerism, tolerance and anti-tumor response in a patient with refractory lymphoma receiving non-myeloablative conditioning and a haploidentical related allogeneic bone marrow transplant.

Author

Toh, H.C., Spitzer, T.R., Preffer, F., Alexander, S.I., McAfee, S., Dombkowski, D., Clark, J.S., Colby, C., Saidman, S., Sackstein, R., and Sykes, M.

Subjects
LYMPHOCYTES, MOSAICISM, BONE marrow transplantation
Abstract

A 51-year-old patient with refractory non-Hodgkin lymphoma (NHL) received non-myeloablative conditioning and a two of six (A, B, DR) human leucocyte antigen (HLA) mismatched donor BMT. Post-BMT lymphocytes showed fluctuating T- and natural killer (NK)-cell chimerism, which culminated in mainly donor lymphocytes by Day + 100. Changes in lymphocyte chimerism correlated with antidonor and anti-host responses in mixed lymphocyte reaction (MLR). On Day + 100, a strong anti-host response was observed in MLR in the absence of graftversus-host disease (GVHD), together with near complete regression of the patient's lymphoma. A mild chronic GVHD later developed and, eventually, by 680 days postBMT, the lymphoma had relapsed and MLR reflected a state of global immune unresponsiveness. These observations demonstrate evolving host-versus-graft and graftversus-host tolerance that correlates with fluctuating lymphoid chimerism and graft-versus-lymphoma (GVL) effects, in the absence of severe GVHD. Eventual lymphoma relapse temporally correlated with a generalised immunosuppressed state. [ABSTRACT FROM AUTHOR]

Published
2002
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