Tribocorrosion and metal release from austenitic stainless steels 304 and 201 in simulated cassava food contact

Cassava is the third most significant calorie source in the tropics. Its processing has changed from traditional methods to stainless steel processing machines. This study investigated the influence of cassava on metal release from two common stainless steels, ASTM 304 and 201, with and without friction, and on tribocorrosion (multianalytically) of 304. Cassava was relatively corrosive and hindered repassivation of the surface oxide of stainless steel, but it also acted as a lubricant against mechanical friction. The combined action of friction and cassava caused a significant increase in iron, chromium, nickel, and manganese release from the stainless steels (30–35- fold increase compared to no friction, and 4–12-fold increase compared to water without cassava but with friction)

Blood biochemistry and haematology of weaner rabbits fed sun-dried, ensiled, and fermented cassava peel-based diets

Twenty-four New Zealand white × Chinchilla weaner bucks, aged between 7 and 8 weeks and averaging 0.9 kg in weight, were divided into four groups of six each and used in a 12-week feeding trial to evaluate the blood biochemistry and haematology of rabbits fed sun-dried, ensiled, and fermented cassava peel-based diets. The test diets designated A, B, C and D were completely randomised. Diet A, the control, was a 16.18 per cent CP (crude protein) weaner ration formulated from maize, maize offals, soya bean meal, blood meal, oyster shell, bone meal, vitamin premix, and common salt. Diets B, C and D were also weaner rations of, respectively, 16.10, 16.20 and 16.08 per cent CP in which 10 per cent maize of the control diet was replaced, respectively, with sun-dried, ensiled and fermented cassava peels. The diets were roughly iso-caloric. The haematological components of the study included packed cell volume (PCV), white blood cells (WBC), neutrophil (N), and lymphocytes (L). The biochemical parameters were serum creatinine, urea, bilirubin (total and conjugated), serum glutamic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT), eosinophil, and blood sugar. Liver and kidney weights were also monitored. The results showed that PCV, WBC, N and L were affected (P0.05) among rabbits fed different dietary treatments. Vingt-quatre lapins mâles en sevrage de l\'espèce de Nouvelle - Zélande blanc × Chinchilla agé de 7 à 8 semaines et de poids moyen de 0.9 kg étaient divisés en 4 groups de 6 lapins chacun et employés dans un essai d\'alimentation de 12 semaines pour évaluer la biochimie et l\'hématologie de sang de lapins nourris de régimes à base de pelure de manioc séchée de soleil, ensilées et fermentée. Les régimes d\'essai classés A, B, C et D étaient complètement choisis au hasard. Le régime A, le contrôle, était une ration de sevrage avec 16.18% de CP (protéine brute) formulée de maïs, déchets de maïs, farine de graine de soja, farine sanguine, coquille d\'huître, engrais de cendres d\'os, vitamine prémix et sel ordinaire. Les régimes B, C et D étaient aussi des rations de sevrage, respectivement, avec 16.10, 16.20 et 16.08% de CP enquel 10% de maïs du régime de contrôle était remplacé par les pelures de manioc, respectivement, séchée de soleil, ensilées et fermentée. Les régimes étaient approximativement iso-cloriques. Les éléments hématologiques de l\'étude comprenaient la volume de cellule tassée (VCT), le globule sanguin blanc (GSB), le neutrophile (N) et les lymphocytes (L). Les paramètres biochimiques étaient le sérum créatinine, l\'urée, la bilirubine (totale et conjuguée), le sérum glutamique transaminase (SGPT), le sérum glutamique oxaloacétique transaminase (SGOT), l\'éosinophile et le sucre dans le sang. Les poids de foie et de rein étaient également suivis de près. Les résultats montraient que VCT, GSB, les neutrophiles et les lymphocytes étaient modifiés (

Growth, keratinolytic proteinase activity and thermotolerance of dermatophytes associated with alopecia in Uyo, Nigeria

Mycological research was conducted on the mycelial growth, keratinolytic proteinase activity and thermotolerance of dermatophytes associated with alopecia patients in Uyo, Nigeria. The results revealed that Microsporum sp. — AP1 , Epidermophyton sp. — AP2 , Trichophyton rubrum — AP4 , Trichophyton mentagrophytes — AP5 and a yeast Candida albicans — AP3 isolated exhibited variable growth and keratinase activity at different temperatures. Microsporum sp. — AP1 and T. mentagrophytes — AP5 survived heat treatment at 90 °C but exhibited best mycelial growth at 30 °C (with 53.41 mg/50 ml biomass dry weight) and 40 °C (with 61.32 mg/50 ml biomass dry weight) respectively, after incubation for 2 weeks. Trichophyton rubrum — AP4 and Epidermophyton sp. — AP2 could not survive heat treatment at 90 °C but grew better at 40 °C (with 38.52 mg/50 ml biomass dry weight) and 30 °C (with 48.32 mg/50 ml biomass dry weight) respectively, over the same incubation period, while C. albicans — AP3 grew better at 30 °C with 38.7 mg/50 ml biomass dry weight after 2 weeks, but failed to survive at 70 °C. All the isolates except Candida albicans — AP3 survived at 80 °C and exhibited great potential to elaborate keratinolytic enzymes, with T. mentagrophytes demonstrating the best potential at 30 °C and 40 °C. Higher temperatures tended to reduce keratinolytic activities and there were significant (P <0.05) relationships between biomass weight and enzyme productivities of all the isolates except T. mentagrophytes . This indicates that in some dermatophytes keratinolytic proteinase activity is not a function of cell multiplicity. This plus the high thermostability of the enzymes are important attributes in the consideration of preventive and therapeutic methods against dermatophytes in the tropics

Heat resistance of dermatophyte’s conidiospores from athletes kits stored in Nigerian University Sport’s Center

The incidence and heat resistance of conidiospores produced by dermatophytes isolated from athlete’s kits (canvasses, stockings and spike shoes) stored in Nigerian University Sport’s Centre were investigated. Epidermophyton floccosum, Microsporum oudouinii, Microsporum canis, Trichophyton concentricum, Trichophyton mentagrophytes and Trichophyton rubrum were isolated and their incidence on the athlete’s kits varied with the species and type of kits. Among the isolates T. mentagrophytes, T. rubrum and E. floccosum with 25%, 23% and 20% prevalence rates respectively, were the most common isolates, and are often associated with tinea pedis (athletes foot). Canvasses with the highest incidence of dermatophytes (25 out of 34 fungal isolates) were the most contaminated kits and could serve as effective articles for the transmission of tinea pedis among athletes in Nigeria. The common etiological agents screened, produced asexual spores (conidiospores) that exhibited high resistance to heat treatment at 80 °C. Of the three isolates, E. floccosum , with a decimal reduction time ( D -value) of D80 = 4.4 min was the most resistant followed by T. mentagrophytes with D80 = 4.0 min and then T. rubrum with D80 = 3.2 min. The spores elimination pattern indicates that increasing the heating duration would decrease the decimal reduction time and possibly denature the fungal propagules but may damage the skin during treatment with hot water compresses. The findings have shown that the use of hot water compresses is palliative but heat treatment especially vapour-heat treatment offers adequate preventive measures if applied for periodic treatment of contaminated kits. However, determining the correct condition for effective decontamination will require detailed understanding of the heat resistance of fungal spores. Otherwise treatment of kits with detergent and chaotropic agent such as urea and guanidinium salt is preferred to heat treatment

Comparative Study of the Corrosion Inhibition Efficacy of Polypropylene Glycol and Poly (Methacrylic Acid) for Mild Steel in Acid Solution

<div><p>The performance of polypropylene glycol (PPG) and poly (methacrylic acid) (PMAA) as corrosion inhibitors for mild steel in acid solution was assessed by weight loss, electrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization), and surface analysis (water contact angles) techniques. Results obtained showed that both polymers inhibited mild steel corrosion but PPG was the best inhibitor. Inhibition efficiency increased with the increase in inhibitor concentration but decreased with temperature rise. Polarization results show that both PPG and PMAA behaved as a mixed-type inhibitors. The adsorption of the polymers onto the mild steel surface followed Temkin adsorption isotherm model. The variation of inhibition efficiency with temperature point toward physical adsorption which is supported by the kinetic and thermodynamic parameters derived from the experimental data. Water contact angle measurement results show that the polymers were adsorbed onto the mild steel surface.</p></div