Pitting corrosion and its inhibition for Cu-Fe and Cu-Al-Fe alloys in sodium chloride solutions

The pitting corrosion of Cu-5% Fe alloy [1] and Cu-10%Al-4,9%Fe alloy [II] in sodium chloride solutions was studied, using the potentiodynamic anodic polarization and galvanic current-time measurements. From the potentiodynamic anodic polarization curves the pitting corrosion potential was evaluated. The pitting potential of the two alloys varies with the logarithm of Cl[-] ion concentrations according to sigmoidal curves, which was explained on the basis of formation of passivitable, limiting active and continuously propagated pits depending on the concentration of chloride ions. Alloy [I] had higher resistance to pitting corrosion than alloy [II]. The integrated charge amount, q[a], in presence of Cl[-] ions was taken as a measure of the extent of pitting corrosion, while the difference in values between pitting potential and repassivation potential [E[pit]-E[p]] was taken as a measure of pit repassivation ability. The galvanic current-time measurements indicated that the induction periods become shorter with the increase of Cl[-] ion concentrations. Addition of inorganic anions individually or in mixtures to sodium chloride solutions caused inhibition of pitting corrosion of both alloys. This was indicated from the shift of E[pit] to noble direction in presence of these additives. The inhibition efficiency of the additives was calculated from the change of the integrated anodic charge [q[a]] and induction period in the absence and presence of inhibitors. It was found that the inhibition efficiency depends on the concentration and type of the additive. The synergistic effect manifested itself in presence of mixed additives

Pitting corrosion inhibition of some copper alloys in NaCl solutions by straight chain carboxylates

Electrochemical methods were used to investigate the abilities of the homologous straight chain monocarboxylates [C[n]H[2n+1]COO, n=1-13] to inhibit the pitting corrosion of two types of copper alloys in NaCl solutions. The copper alloys were alloy [I] [Cu + 4.47% Fe] and alloy [II] [Cu + 10.67% Al + 5.02% Fe]. It was found that these were susceptible to pitting corrosion in NaCl solutions, with increase of Cl[-] ions concentration. Alloy [II] was more susceptible to pitting corrosion than alloy [I]. The inhibition performance of the monocarboxylates was critically dependent upon their chain length. The range of chain lengths producing optimal inhibition efficiency was [6

parasitological study on the use of biotherapeutic yeast in the treatment of Schistosoma mansoni infected mice

Infection with Schistosoma mansoni induces humoral and T cell mediated responses and leads to a delayed hypersensitivity that result in granulomatous inflammatory disease around the parasite eggs. The nonpathogenic Saccharomyces species have potential as an exogenously administered agent for maintaining colonization resistance during antibiotic therapy, preventing diarrhea and other gastrointestinal diseases as well as its antagonistic activity [in vitro and in vivo] against various bacterial pathogens. Saccharomyces boulardii exerts its immunoprotective effect through the secretion of immunoglobulins. In this work the antibilharzial effect of S. boulardii and Saccharomyces cerevisiae was studied. Both yeast products were given orally to mice for 21 days before infection. Their effects on worm burden, egg count, fecundity and granuloma diameter were elucidated. Both were effective in reducing worm burden and egg count resulting in a significant decrease in granuloma diameter. The obtained data show that S. cerevisiae gave more potent effects on S. mansoni parasitism than S. boulardii

Evaluation of the antibilharzial activity of mirazid versus praziquantel against S. haematobium: an experimental study

Mirazid [myrrh] is a new herbal extract [oleo gum resin from the stem of the plant Commiphora molmol with claimed antibilharzial activity. LD16, LD50, and LD84 of Mirazid were determined in albino mice and were found to be 1984, 3138, and 4963 mg/kg respectively. The antibilharzial efficacy of Mirazid, administered orally at a dose of 250X5 mg/kg, in comparison to the schistosomicidal drug of choice praziquantel [PZQ], administered orally at a dose of 250X2 mg/kg, was evaluated in S. haematobium infected hamsters. Treatment was conducted 90 days post infection. Parasitological parameters expressing cure and hepatic histopathological changes were evaluated 4 weeks after treatment. Praziquantel treatment completely eradicated S.haematobium worms, caused disappearance of immature and mature egg stages, with 100% dead eggs. Hepatic and intestinal tissue egg loads were reduced by 79.2% and 99.7% respectively. Mirazid failed to induce any significant change in total number of worms, but induced significant reduction in the 1[st], 2[nd], and 3[rd] immature egg stages with increase in the number of the fourth stage, but this change was not reflected on the total number of immature eggs. Mirazid did not affect tissue egg load. The hepatic histopathological changes induced by S. haematobium infection were improved in praziquantel treated hamsters with reduction in granuloma number and size. Ova degeneration with regression of granulomatous inflammatory reaction was more manifested when compared to infected untreated controls. Mirazid did not results in evident regression of hepatic schistosomal pathology. In conclusion, praziquantel is still the drug of choice for treatment of S. haematobium, while Mrazid cannot substitute PZQ in the treatment of S. haematobium. Further trials using modified preparations may result in better antibilharzial efficacy of this novel herbal extract preparation

Hypolipidemic activity of carvedilol, moxonidine and rilmenidine in experimentally-induced hyperlipidemia in rats

Hypertension remains the most common chronic disease in the industrialized world. Reduction of blood pressure is no longer the therapeutic goal of antihypertensive treatment. Hypertension is a well documented risk factor for dyslipidemia, coronary artery, cerbrovascular and renovascular diseases. Carvedilol, moxonidine and rilmenidine were investigated for their hypolipidemic effect in hyperlipidemic rats. All these drugs induced significant reduction in serum total cholesterol [TC], triglycerides [TG] and low density lipoproteins cholesterol [LDL-c], while high density lipoproteins cholesterol [HDL-c] was increased significantly in experimentally-induced hyperlipidemic rats. Also there is significant reduction in LDL-cHDL-c ratio. The obtained data indicate the beneficial effect of carvedilol, moxonidine and rilminidine as hypolipidemic drugs

On the pathogenicity of attenuated Schistosoma mansoni cercariae released from metabolically disturbed Biomphalaria alexandrina

In this study, Biomphalaria alexandrina was treated with sublethal concentrations [LC10] of the dry powdered leaves Solanum nigrum or the whole dry Ambrosia maritima. The two plants affected the development of schistosome parasite within snails by disturbing the glycolytic flux, the most important metabolic pathway for schistosome-infected snails. Attenuated cercariae released from the treated snails were used to infect male albino mice to evaluate their pathogenicity compared with the control cercariae shed from the untreated snails. Most of the males and females detected in these animals measured 0.4-0.6 and 0.6-1.2 mm, respectively, released from mice infected with normal cercariae. The egg count in the liver and intestine of mice infected with attenuated cercariae was remarkably lower showing a reduced fecundity of worms developed from attenuated cercariae. The number and size of granulomatous reactions showed a remarkable reduction in the attenuated cercariae-infected mice. The biochemical analyses for the pathogenicity achieved with attenuated cercariae showed that while serum aspartate and alanine aminotransferases [AST and ALT] were more or less similar, depleted glycogen and elevated lipid peroxides were normalized when compared with those infected with normal cercariae

Possible antischistosomal activity of the crude saponins of Anagallis arvensis on Schistosoma mansoni

This study was carried out to evaluate the antischistosomal efficacy of the crude saponins isolated from Anugalfis amemis [a medicinal local plant] in albino mice experimentally infected with Schistosoma mansoni. Animals were divided into 2 major groups according to the route of drug administration. The first group was orally given the saponins, while the latter one was administered the crude saponins subcutaneously.Different doses of the saponins were used at different intervals of infection. Animals were sacrificed 8 weeks after the infection. Data obtained from some experimental subgroups showed that significant reduction in total number of worm burden was recorded. The worm reduction was variable according to the dose, time, duration and pathway of administration and it ranges from 1.15-100%. This study gave preliminary promising results that help in finding a new, safe and effective chemotherapeutic drug; however, it needs more comprehensive follow-up study

Inhibition of copper corrosion in acidic solution by 2-thio-imidazol-4-one

Many studies have been reported on the inhibition of the corrosion of copper in an aqueous acid or neutral solutions by benzotriazoles [1-5]. The inhibition mechanism of the corrosion of copper by benzotriazoles and its derivatives Was previously reported [6-8] The inhibition effects of ring substituted benzotriazoles on the corrosion of copper in chloride and sulphate solutions were investigated [9-12]. Recent studies on the corrosion inhibition of copper by some heterocyclic compounds [13], viz., tosyl hydrazine, 4, nitrobenzoyl-hydrazine and terephthalye [14], piperidine, piperidones and tetrahydrothiopyrones [15] silane-modified imidazoles [16] and benzenethiols [17] have been reported. The present study aims to investigate the effect of some controlling factors on the corrosion inhibition of copper in HNO- by 2-thio-imidazol-4-one I such as inhibitor concentration and temperature applying a weight loss and polarization techniques

electrochemical and corrosion behaviour of aluminium-magnesium [3 and 5%] alloys in alkaline chromate solutions

Corrosion rates of aluminium-magnesium [3 and 5%] alloys have been measured at 30C, in 0.05 M NaOH containing 10-5 to 1 M potassium chromate. At low concentrations /< 10-3 M, the chromate ion promotes the corrosion through catalyzing the hydrogen evolution reaction. At higher concentrations, corrosion inhibition was noticed through the formation of a protective film. Generally, the alloys are more resistant to corrosion than pure aluminium. Galvanostatic cathodic and anodic polarization was carried out at different current densities up to 10-2 A/cm-2. The cathodic curves exhibited Tafel relation with a slope of ca 0.14, indicating that hydrogen evolution was governed by slow discharge. Tafel relations were also obtained on anodic polarization, the slope of the V/c.d. curves amounted to 0.1, indicating that the first oxidation step of aluminium is the rate- determining step. At relatively high current densities anodic passivity occurred at c.d. decreasing with increase of the chromate concentration

Pharmacological and toxicological effects of cardia maclodii

Pharmacological and toxicological effects of ethanolic and aqueous extracts of each of the fruits [Ia,b], bark [IIa,b], flowers [IIIa,b], and leaves [IVa,b] of Cordia maclodii were investigated in albino rats. The acute LD50 of Ia,b, IIa,b, and IVa were 2.4, 1.5, 1.25, 1.5, 1.5, 1.6, 1.25 and 1.50 g/kg body weight, respectively. All tested extracts exhibited significant analgesic and anticonvulsant activities. Extracts IIIa,b and Ia had anti-inflammatory effect in the chronic model in rats. Extracts IVa and Ib recorded the highest incidence of ulcer numbers, while IIIa,b were completely devoid of ulcerogenicity. All tested extracts, except IIa,b were effective as glucose lowering agents in diabetic rats. Extracts IIIa,b and IIb showed significant diuretic effect. The phytochemical screening indicated that all the extracts contain polysaccharides, while extracts Ia, IIIa,b and IVa,b contain flavonoids

Some hepatotoxic and reproductive effects of vincristine sulphate and doxorubicin chloride in normal and liver damaged male rats

Vincristine sulphate [I] and doxorubicin hydrochloride [II] in large doses for short time increase significantly serum liver enzymes in both young and aged rats. Smaller doses from each and both in combination failed to affect liver enzymes of young rats, also smaller doses from all treatments for 21 days failed to affect liver enzymes of young and liver damaged rats. Smaller or larger doses for short or long periods significantly affected liver enzymes of aged rats. [I] in large or small doses did not affect the sperm quality or internal organs, while [II] significantly affected sperm quality when given alone or with [I] in all conditions