Search results

The purpose of this investigation is to study the corrosion inhibition of carbon steel (CS) using a “green” inhibitor, Opuntia ficus-indica, in an aerated, 0.5 M H₂SO₄ solution at different concentrations and temperatures.

Weight loss determinations, surface studies, electrochemical impedance spectroscopy and potentiodynamic polarization were applied during the investigation.

It was observed that Opuntia ficus-indica extract can decrease the corrosion rate of CS, and its efficiency increases with increasing concentration up to 1,000 ppm and with time, but decreases with increasing the temperature from 25 to 600C. The inhibitory activity is due to the presence of phenolic compounds in its chemical structure.

The work was done under static conditions, whereas in acid cleaning conditions, there is a dynamic system. However, the findings may apply to both the systems.

CS is used in acidic environments in the acid cleaning industry.

Results of this work show that it is possible to reduce the cost of repair of equipment and the environmental impact of corrosion.

There are very few investigations on the study of Opuntia ficus-indica leaf extract as a green inhibitor in an acidic environment.

The purpose of this study is to investigate the effect of a 15-week dietary intake of cactus flour on metabolic parameters, body weight and dietary intake of rats.

Male Wistar rats were divided into four experimental groups (n = 8-10): control or westernized diets added or not of cactus flour. The following parameters were evaluated during the period of dietary manipulation: body weight, food intake, glycemic and lipid profile (oral glucose tolerance test, metabolic parameters, hepatic and muscular glycogen dosage), visceral and body fat (relative weight to body weight). Data were analyzed using Graphpad Prism®5, p = 0.05.

Animals fed on a Western-style diet together with flour cactus presented lower weight gain (335.7 ± 20.0, p = 0.05) over the evaluated period, even when the volume of food intake was not different among the groups. The addition of cactus flour to a Western-style diet appears to lower glucose levels at 30 and 60 min (p = 0.05), as shown in the glucose tolerance curve. There was a downward trend does fat stores, cholesterol levels and triglycerides. Therefore, it was concluded that this addition cactus flour is effective even when the diet is hyperlipidic, demonstrating its ability to attenuate risk parameters for the occurrence of metabolic syndromes such as sub fraction high cholesterol levels and glucose tolerance.

The addition of functional foods to diets may work to improve the harmful effects of this type of diet. Opuntia ficus indica has high nutritional value and has hypoglycemic and hypolipemic properties besides being antioxidant.

The effects of Opuntia ficus indica (OFI) cladodes on uricemia level, endothelial dysfunction and oxidative damage were studied in young rats fed a cafeteria diet (CD).

A total of 16 young male Wistar rats (weighing 110 ± 20 g and four weeks old) were divided into two homogenous groups. The first group received a CD containing 50% of hyperlipidic diet and 50% of junk food mix (processed mix: hyper-fat, hyper-salted and sweetened) (CD group), and the second group (CD + OFI nopalitos) received the same diet supplemented with 50 g of fresh OFI nopalitos (young cladodes) for 30 days.

OFI nopalitos regulate the hyperuricemia, improve the endothelial dysfunction by raising the bioavailability of nitric oxide(NO) and reduce prooxidant markers by reducing lipid peroxidation and protein oxidation (p < 0.05) and boosting antioxidant capacity and enhancing the antioxidant enzymes activities (p < 0.05) in blood and aorta tissues of rats early fed with a high-fat diet /junk food.

By-products of OFI have specific functional properties that may be beneficial in metabolic disorders and offer a better alternative with an economic and sustainable development perspective.

By-products of OFI highlight potential functional properties mainly based on its potent antioxidant capacity. By-products of OFI can be used as a promising nutraceutical resource to prevent various metabolic disorders in relation with cardiovascular diseases or hyperuricemia in subjects consuming junk food and or living in the Western society to reach the objectives of health policy and maintain a sustainable health system development.

The purpose of this study was to investigate the effects of prickly pear (Opuntia ficus indica (OFI)) nopalitos on body weight, food consumption, arterial blood pressure, glucidic homeostasis, cholesterol metabolic pathway and tissues redox status in type 2 diabetic (T2D) rats fed a high-fat diet (HFD).

Rats were fed by a HFD containing 30 per cent sheep fat for 10 weeks, after which they were rendered diabetic by an injection of a low dose of streptozotocin (STZ) (35 mg/kg). The diabetic rats were then divided into two groups. The first group consumed the HFD supplemented with 5 per cent (g/100 g diet) of freeze-dried OFI nopalitos (HFD-OFI), and the second group received the HFD without supplementation (HFD).

OFI nopalitos treatment decreased significantly arterial diastolic (−20%; p = 0.0001) and systolic (−16%; p = 0.0001) pressures, glycemia (−14%; p = 0.03), insulinemia (−50%; p = 0.04), glycated hemoglobin (−49%; p = 0.003), homeostasis model assessment insulin resistance (−67%; p = 0.03), cholesterolemia (−31%; p = 0.003), very-low and low-density lipoprotein cholesterol (−38%; p = 0.002 and −63% p = 0.0002, respectively); thiobarbituric acid reactive substances and lipid hydroperoxide contents, respectively, in liver (−26% p = 0.02, −20% p = 0.02), adipose tissue (−30% p = 0.002, −25% p = 0.001), muscle (−29% p = 0.003, −25% p = 0.008) and kidney (lipid hydroperoxides only (−28%; p = 0.001) but increased high-density lipoprotein (HDL₂) cholesteryl esters (+61%; p = 0.0001), serum lecithin: cholesterol acyltransferase activity (+21%; p = 0.006) and antioxidant enzymes activities (superoxide dismutase, glutathione peroxidase and catalase) of some tissues (liver, adipose tissue, muscle and kidney).

Freeze-dried OFI nopalitos improves arterial blood pressure, glycemic control, metabolic pathway of cholesterol and redox status in T2D rats.

This paper aims to evaluate the protective potential of prickly pear cactus fresh cladodes (opuntia ficus indica (OFI)) on glycemic disorders, dyslipidemia, prooxidant/antioxidant stress biomarkers and reverse cholesterol transport (by evaluating the activity of lecithin-cholesterol acyltransferase (LCAT)) and paraoxonase (PON1) in rats prematurely exposed to cafeteria diet (CD).

Sixteen young rats were divided into two groups fed CD containing 50 per cent of hyperlipidic diet (HLD) and 50 per cent of junk food mix supplemented or not with 50 g of fresh young cladodes of OFI to 100 g of CD, during 30 days.

OFI cladodes supplementation decreased significantly body weight (p < 0.001), food intake (p < 0.05), adipose tissue weight (p < 0.01), fasting glycemia and glycosylated hemoglobin (p < 0.01), homeostasis model assessment (HOMA-IR) and insulinemia (p < 0.001), levels of cholesterol (C) (p < 0.05) and triacylglycerols (TG) (p < 0.01) in serum and in very low-density lipoproteins (VLDL-C p < 0.05 and VLDL-TG p < 0.01) and improves reverse cholesterol transport by increasing high-density lipoprotein cholesteryl-esters concentrations (p < 0.001) and by stimulating LCAT activity. Moreover, they attenuated lipid peroxidation in VLDL and low-density lipoproteins by increasing atheroprotective activity of PON-1 and in liver and adipose tissue by enhancing enzymatic antioxidant defence.

The young cladodes of OFI because of their antiobesity benefits could constitute a novel functional ingredient in pharmaceutical and nutraceutical applications.

Young cladodes of OFI in rat precociously submitted to a hyperlipidic diet/junk food (cafeteria model) seem to prevent metabolic disorders associated with obesity.

The purpose of this paper is to determine if a type of cactus mucilage, Opuntia ficus-indica (OFI), may act as a corrosion inhibitor for carbon steel in cement-based materials (mortar) exposed to chloride-laden environment.

Mortar prisms, reinforced with carbon steel rods, were immersed in sodium chloride (NaCl) solution for five wet – dry cycles. The experimentation included electrochemical monitoring (corrosion potential, Ecorr, and polarization resistance, Rp) of carbon steel during the time of exposure until corrosion-induced cracking appeared at the mortar surface. Crack survey on the mortar prisms was performed. Carbon steel rods were retrieved from the mortar after crack survey and steel mass loss at the end of the experimental period was estimated. A comparison between the different mixtures was also performed.

OFI mucilage did perform as a corrosion inhibitor of steel in chloride contaminated mortar.

The experimental program needs to be corroborated in concrete specimens with typical dimensions. The surface oxide/hydroxide formation of the carbon steel in contact with the OFI mucilage is still unknown; thus, electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) analyses are needed.

OFI mucilage is a suitable natural product that can be used to increase durability of concrete structures not only in countries where OFI cactus is produced, but also in many other countries where this plant is considered a plague.

The new information obtained from this paper is the innovative use of a by-product of this cactus plant for construction industry applications.

This paper aims to present experimental results related to the performance of cactus mucilage (CM) and brown seaweed extracts (SEs) to inhibit reinforcing steel bar (rebar) corrosion in saturated calcium hydroxide alkaline solutions (pH = 12.5).

Electrochemical cells were prepared using CM solutions at 0.5, 1 and 1.38 per cent concentration (w/v), SE solutions at 0.5, 1, 1.38, 2 and 3 per cent concentration (w/v), sodium alginate at 1 per cent concentration (w/v) and calcium nitrite at 11.3 per cent (v/v). Each cell contained six deformed reinforcing steel bars of 9.5 mm nominal diameter. The experiments were performed at 23 ± 2°C in two stages. The first stage was aimed at stabilizing the rebar until passivation was reached. The second stage included adding NaCl in six steps from 0.5 to 16 g/L. Half-cell potential, linear polarization resistance and electrochemical impedance spectroscopy measurements were monitored during both stages.

The electrochemical test results indicated that both additions reduce the corrosion rate of rebars and pitting in an alkaline media with chloride ions (16 g/L NaCl). Electrochemical impedance spectroscopy results for rebars in natural-added solutions showed higher charge transfer resistance and double layer capacitance values, indicative of the formation of a second interface between the rebar and the electrolyte.

The information obtained was for alkaline solutions only. Further investigation is performed using concrete as the alkaline electrolyte.

CM and SE may be suitable low-cost corrosion inhibitors for steel in concrete.

The use of botanical or algae products for this application will encourage people to consider its production for this particular application. Also, the possible harvest in an environmental friendly way will diminish in the future the use of biohazards and toxic inhibitors.

This investigation is a continuation of a one presented in 2007, which uses only nopal mucilage. This new investigation corroborates what was concluded in the early investigation and incorporates a new natural by product, algae, as a possible corrosion inhibitor product.

The purpose of this paper is to study the ability of commercial tara powder to convert rust into iron tannate and evaluate their use as raw material for the formulation of water based rust converter.

Water-borne acrylic primers were formulated with tara powder and aqueous tara extract and applied on steel rusted by three different methods. The conversion of rusted steel by tara tannins was studied by X-ray diffraction spectroscopy, infrared spectroscopy and scanning electron microscopy. The acrylic primers, containing hydrolysable tannins, were coated with alkyd finish and were evaluated in comparison to commercial systems in accelerated corrosion tests. The corrosion inhibition effects of tara powder on mild steel in 0.1M NaCl were studied by DC electrochemical techniques.

Tara tannin converts rust to ferric tannate and increases the magnetite content of rusted steel. The water-based acrylic primer formulated with aqueous extract of tara, alkyd-coated finish, showed performance equivalent to pure alkyd system.

The chlorides content in the commercial tara powder can be screened the beneficial effect of hydrolysable tannins to convert rust. Furthermore, the water-based rust converter formulated with acrylic resin may be sensitive to salt contamination of rust.

Hydrolysable tannins from commercial tara powder have not been studied yet in its application to the development of rust converters. A water-based primer formulated with commercial tara powder developed for the effective treatment of rusted surfaces can be of interest as an environmentally friendly to current commercial approaches.

In the last few decades the cultivation of cactus pears represents an important element in the economy of subtropical regions with scarce water resources. The increasing market competition from other countries has forced Sicilian producers to modernise the packing houses where the fruit is processed. The study carried out has shown that the technology employed in the newest packing lines is of a high level and that a low level of human, material and energy resources are necessary; moreover, packing and despining need further innovations. Trials conducted with an instrumented sphere IS100 has permitted critical points on the packing lines to be identified and to identify materials on which the fruit impacts during the processing.

The diet of spotted hyenas (Curocuta curocuta) was studied in Endrta Woreda, southern Tigray, Ethiopia from September to December 2009. Hyena scats were collected throughout the study period from all areas and the samples were washed and hairs were extracted. Hair was analyzed on form, length and color with the naked eye as well as on a scale patterns using a microscope at 10 x magnifications and was compared with a prey species hair reference collection. Faecal analysis revealed that the diet of the spotted hyena contains only prey item of domestic livestock. Frequencies of prey remains of donkey, sheep, goat and cattle were highest with sheep being by far the most common prey species. Household survey of livestock depredation of spotted hyenas revealed that a total of 364 spotted hyena attacks were reported of which donkeys were significantly more likely to be reported as lost to hyena predation, representing 31.87 per cent, followed by goats (14.56 per cent) and sheep (10.71 per cent). It seems most likely that carnivores deepened entirely on domestic prey species for their dietary requirements. Detailed information on the population size and density of spotted hyena is needed to give a better picture of the status of this carnivore species in Tigray, northern Ethiopia and to help resolve conflicts with livestock. Further investigations into the seasonal variation of predation are recommended