15 research outputs found
Synergistic effect of colchicine and iodide ions on the corrosion of mild steel in 0.5 M H2SO4
The inhibition behavior of colchicine (CC) on the corrosion of mild steel in 0.5 M H2SO4 was evaluated by electrochemical methods such as potentiodynamic polarization and electrochemical impedance spectroscopic measurements. The inhibition efficiency increases with increasing concentration of CC. The potentiodynamic polarization results reveal that CC act as a mixed-type inhibitor by retarding both cathodic and anodic corrosion reactions. Additionally, the synergism was carried out between CC and KI to improve the corrosion inhibition behavior of CC on mild steel. The adsorption of both CC alone and the combined inhibitor (CC + KI) on mild steel surface follows Langmuir adsorption isotherm. The synergism parameter (S (theta) ) was calculated to recognize the existence of synergism between CC and iodide ions. Lastly, an adsorption mechanism of CC molecules with iodide ions is discussed
Electrochemical, gravimetric and quantum chemical analysis of mild steel corrosion inhibition by colchicine in 1 M HCl medium
The inhibition effect of colchicine (CC) on mild steel (MS) corrosion in 1 M HCl solution has been investigated by electrochemical techniques such as electrochemical impedance spectroscopy, potentiodynamic polarization, chronoamperometry and also by the gravimetric method. Polarization studies showed that CC acts as mixed type corrosion inhibitor. The inhibitor adsorption process in the MS/CC/HCl system was studied at different temperatures (303-333 K). The adsorption of CC on MS surface is an exothermic process and obeys the Langmuir adsorption isotherm. Based on potential of zero charge values and quantum chemical parameters, the mechanism of adsorption has been proposed
Characterisation of the Plasmodium falciparum Hsp70-Hsp90 organising protein (PfHop)
Malaria is caused by Plasmodium species, whose
transmission to vertebrate hosts is facilitated by mosquito
vectors. The transition from the cold blooded mosquito
vector to the host represents physiological stress to the
parasite, and additionally malaria blood stage infection is
characterised by intense fever periods. In recent years, it
has become clear that heat shock proteins play an essential
role during the parasite's life cycle. Plasmodium falciparum
expresses two prominent heat shock proteins: heat shock
protein 70 (PfHsp70) and heat shock protein 90 (PfHsp90).
Both of these proteins have been implicated in the
development and pathogenesis of malaria. In eukaryotes,
Hsp70 and Hsp90 proteins are functionally linked by an
essential adaptor protein known as the Hsp70–Hsp90
organising protein (Hop). In this study, recombinant P.
falciparum Hop (PfHop) was heterologously produced in E.
coli and purified by nickel affinity chromatography. Using
specific anti-PfHop antisera, the expression and localisation
of PfHop in P. falciparum was investigated. PfHop was
shown to co-localise with PfHsp70 and PfHsp90 in parasites
at the trophozoite stage. Gel filtration and coimmunoprecipitation
experiments suggested that PfHop
was present in a complex together with PfHsp70 and
PfHsp90. The association of PfHop with both PfHsp70 and
PfHsp90 suggests that this protein may mediate the
functional interaction between the two chaperones