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Santiago del Estero, Argentina

The National University of Santiago del Estero is an Argentine national university located in the capital of Santiago del Estero Province. Its 1973 establishment gathered the existing Tucumán University school of agronomy and the Córdoba University forestry institute , as well as new schools created for the purpose. Wikipedia.

Nazareno M.A.,National University of Santiago del Estero
Acta Horticulturae | Year: 2013

A review of the latest world-wide findings from scientific studies about the medicinal properties of cactus products is presented as well as their traditional and popular uses. Plants were used by ancient civilizations to cure diseases and heal wounds for thousands of years. Cactus cladodes, fruits, and flowers have been traditionally used as medicines in several countries. Cladodes are still used in folk medicine for the treatment of gastric ulcer and for its healing activity as therapeutic agents. The properties of the infusions of cactus dried flowers to prevent prostate cancer are also well-known. Remarkable progress has been made over the past decades in disease prevention considering fruit, vegetables and herbs. Recent scientific investigations confirmed that cactus products may be efficiently used as a source of phytochemicals, such as mucilage, fibres, pigments and antioxidants. Scientific studies in experimental models confirmed that lyophilized cladodes have significant anti-ulcer effect, protective effect against gastric lesions as well as antiinflammatory activity. Diet supplementation with cactus pear fruits in healthy human has shown to decrease the oxidative stress, and, therefore, improves their overall antioxidant status. Cactus pear fruits have also been studied as ovariancancer preventive. Their ability in suppressing carcinogenesis of in vitro and in vivo models has been assessed. Opuntia ficus-indica cladodes were supplied to hypercholesterolemic rats and a marked decrease in cholesterol and triglycerides levels was found in plasma samples. Experiments in diabetes mellitus non-insulindependent patients have confirmed the hypoglycemic effects of Opuntia streptacantha cladodes. Moreover, consumption of cactus young cladodes has shown to reduce obesity and blood glucose. Experiments concerning the antiviral action of cactus cladode extracts have been conducted against viruses such as herpes, HIV-1 virus and influenza A. Functional properties of cactus products can be exploited more efficiently in the food, cosmetic, and pharmaceutical industries if research is encouraged. Source

Bravo S.,National University of Santiago del Estero
IAWA Journal | Year: 2010

This study examined anatomical responses to fire damage of the cambium in Schinopsis lorentzii and Aspidosperma quebracho-bianco. Bole cross sections were extracted from specimens with external signs of fire damage. Samples were taken from zones designated normal, discoloured and wound altered. The vessel, fibre, axial and ray parenchyma percentages, tangential vessel diameter, vessels per mm2, rays per mm, and ray width and height of these zones were compared. Fire scars and fire marks were identified on cross sections of S. lorentzii and A. quebracho-bianco. The fire marks reflect minor wounds that did not affect wood formation. The fire scars, on the other hand, are the result of wounds that interrupted cambial activity thus affecting the shape of the bole and causing discolouration of pre-existing wood adjacent to wounds. The wood formed after fire damage included callus, barrier zones at fire scar edges and the formation of ribs of wound wood. The wound altered zone was characterised by a decrease in the percentage of vessels and fibres, an increase in the percentage of axial parenchyma, the formation of grouped rays, a decrease in vessel tangential diameter, and occurrence of fibres with atypical structure. Disorientation in the axial xylem system was observed in the barrier zone. The anatomical responses to cambium damage and formation of discoloured wood and woundwood ribs suggest that wood quality and utilisable volume of bole in the studied species is affected by fire. Source

Durana E.B.,National University of Santiago del Estero | Amandib A.,CONICET
Interactive Learning Environments | Year: 2011

Student models are crucial components in personalised distance learning environments. These models usually include individual characteristics such as the level of knowledge of a given topic, the learning style or the type of personality, the level of participation and so on. However, when the focus is on group activities, these learning environments often use group characteristics, losing sight of the individuals in the groups. Therefore, a student model considering individual characteristics in groups is introduced in this article. This model is built by automatically analysing collaborative behaviour and capturing the context in which it appears. A particular contribution of this approach is focused on a flexible structure of collaboration contexts which are defined at runtime. This approach has been proven in simulated and real environments showing promising results, provided that a given collaborative behaviour is found in at least 20% of the captured actions. © 2011 Taylor & Francis. Source

Nazareno M.A.,National University of Santiago del Estero
LWT - Food Science and Technology | Year: 2011

Flavonoids and ascorbic acid are antioxidants usually consumed together in foods, taking this into account, the antiradical capacity of mixtures of ascorbic acid with some representative flavonoids (flavanones, chalcones and flavonols) against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH. ) was evaluated. Antiradical capacities of naringin, naringenin, hesperidin, hesperetin, naringin chalcone, naringin dihydrochalcone, rutin and quercetin were measured alone and in different combinations with ascorbic acid. Experimental and theoretical values of antiradical activities for these mixtures as well as the values obtained in sequential reactions were compared in order to determine synergistic or antagonistic effects. Among the different ascorbic acid-flavonoid combinations analyzed only the mixture with naringin or quercetin exhibited synergistic effects, the mixture activity being 33 and 18% higher than the theoretical value, respectively. On the contrary, antagonistic effects were found in the cases of rutin, hesperidin, naringin chalcone, naringin dihydrochalcone and naringenin. Moreover, only hesperetin showed an additive effect. These behaviours were ascribed to the regeneration of the oxidized species on the basis of the structural features of each flavonoid and their different reactivity against DPPH. These results show that the antiradical activity can be modified by the interaction among the mixture constituents and this may be considered to improve antioxidant formulations. © 2010 Elsevier Ltd. Source

Zanini V.P.,National University of Santiago del Estero | Lopez De Mishima B.,National University of Santiago del Estero | Solis V.,National University of Cordoba
Sensors and Actuators, B: Chemical | Year: 2011

A biosensor based on the immobilization of lactate oxidase (LOx) on a glassy carbon electrode modified with laponite/chitosan hydrogels for the quantification of l-lactate in alcoholic beverages and dairy products is presented. Ferrocene-methanol (FcMe) is used as artificial mediator. The purpose of this work is to determine the best hydrogel composition from the analytical point of view. The characterization of the hydrogels was carried out by CV, amperometry and EIS. According to permeabilities and charge transfer resistances for ferrocyanide (used as molecular probe) as well as the enzymatic behavior of the enzyme for l-lactate, the best laponite/chitosan mass ratio found was 25/50. The distinct features of the bioelectrode are its long stability, its ability to reject or minimize most interferents including ascorbic acid, and its excellent analytical response, which allowed the reduction of the enzyme content below 0.5 U, for a sensitivity of (0.326 ± 0.003) A cm -2 M-1, with a time response lower than 5 s and a detection limit of (3.8 ± 0.2) × 10-6 M. Our l-lactate biosensor was validated by comparison with a standard spectroscopic method. © 2011 Elsevier B.V. Source

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