Preparação e caracterização de blendas de quitosana/poli(álcool vinílico) reticuladas quimicamente com glutaraldeído para aplicação em engenharia de tecido

In this study, novel Chitosan/PVA based films were chemically crosslinked by glutaraldehyde, under pH=(4,00 ±0,05), in order to achieve structures tailored for wound tissue engineering applications. Both precursors and developed films were characterized by FTIR, SEM and XRD in order to determine the presence of chemicals groups and nanostructural order, respectively. The results have shown that the glutaraldehyde crosslinking have altered the crystallinity of pure chitosan and the increase on the C=N bands and simultaneous decrease on NH2 bands suggested that Chitosan/GA crosslinking has preference to occur in carbon-2 of the saccharide ring by the Schiff's base reaction. Also, FTIR spectroscopy clearly showed that crosslinking has also taken place with blends of PVA and chitosan. The mechanical properties presented high degree dependence with on the increase of the content of chitosan and glutaraldehyde. The results have indicated that, by controlling the ratio [PVA]/[chitosan] in the blends and the extent of chemical crosslinking, it was possible to tailor the hybrid network produced aiming to obtain properties of interest for the specific application.

Avaliação sensorial de cachaça

The hedonic level of commercial cachaças, was evaluated by consumers and by a tasters. The results of sensorial methods analyzed trough Principal Components Analysis, Hierarchical Cluster Analysis and the Pearson linear correlation indicated that the best classified cachaças were produced in copper stills and aged in oak casks. By contrast the worst classified exhibited as the main features be not aged and high alcohol percentage. The index of preference is positively correlated with the intensity of yellow color, wood flavor, sweetness and fruit aroma. There is a negative preference correlation with the acidity, the taste of alcohol and bitterness.

REAÇÃO DE CONDENSAÇÃO DO GLICEROL COM COMPOSTOS CARBONÍLICOS. SÍNTESE, CARACTERIZAÇÃO E APLICAÇÃO EM CRISTAIS LÍQUIDOS

Condensation reactions of glycerol with aldehydes and ketones were performed under thermal heating and microwave irradiation regimes. Homogeneous and heterogeneous catalysts were tested in both conditions. A silica sulfated (SiO2-SO3H) heterogeneous catalyst demonstrated the best performance relative to a selectivity of >95% in favor of 5-membered ketals. For acetals, preference in favor of 5-membered or 6-membered functional groups depends on the nature of the catalyst. Homogenous catalysts favor the more stable 6-membered acetals, whereas heterogeneous catalysts favor the less stable 5-membered acetals. However, the isomer ratios in the acetalization reaction are too low, and hence the reaction cannot be used in a synthetic plan for functional materials. Ketalization processes mediated by SiO2-SO3H show a high selectivity in favor of a 5-membered ring (1,3-dioxolane). The scope of condensation was tested with different ketones. A mechanism for heterogeneous catalysis related to the selectivity in the cyclization process is presented herein. Solketal, a commercial product, was also obtained by a condensation reaction of glycerol and propanone, and showed a high selectivity in favor of 1,3-dioxolane. It was transformed to potential allylic and chiral intermediates. A mesogenic core was connected to the organic framework of glycerol to produce a monomer liquid crystal material with a stable smectic-C mesophase.

Water consumption when exposed to sun and shade for native goats in the semiarid of the State of Paraiba, Brazil

This work aimed to evaluate the preference and water consumption of native goats in the semiarid of Brazil. The water was freely supplied, in individual buckets, one exposed to the sun and the other in the shade. The experiment was realized using 18 animals of Moxotó, Graúna and Azul breeds, with average weight of 16,6 ± 2,4 kg, kept in confinement in individual stalls equipped with feeders and drinkers, during the period from January to February of 2009. The water temperature was measured by sensors (thermocouples type T - copper/constantan), which were coupled to a system of data acquisition. It was observed that the average water temperature exposed to the sun was 29.02 ºC, and 23.85 ºC in the shade. For all breeds there was a preference for the water exposed to the sun, corresponding to an average consumption of 64.71% of the total. Among the breeds, the greatest preference for water exposed to the sun was the Azul (71.18%), followed by the Moxotó (65.95%) and the Graúna (57.00%). The animals consumed more water during the day, and the average water consumption was 1.15 grams day-1, corresponding to 6.9 % of body weight of the animals.

A multicriteria model to assess tractors used in family agriculture

In recent years, public policy has been offering subsidized credit for machine purchase to family farmers. However, there is no methodological procedure to select a suitable tractor for these farmers' situation. In this way, we aimed to develop a selection model for smallholder farmers from Pelotas city region in the state of Rio Grande do Sul. Building a multicriteria model to aid decisions is divided into three main stages: structuring stage (identifying stakeholders, decisional context and model creation), evaluation stage (stakeholder preference quantification) and recommendation stage (choice selection). The Multicriteria method is able to identify and value the criteria used in tractor selection by regional family farmers. Six main evaluation areas were identified: operational cost (weight 0.20), purchase cost (weight 0.22), maintainability (weight 0.10), tractor capacity (weight 0.26), ergonomics (weight 0.14) and safety (weight 0.08). The best-rated tractor model (14.7 kW rated power) also was the one purchased by 53.3% of local families.

Splenic vein graft for the reconstruction of the mesenteric-portal trunk after gastroduodenopancreatectomy

Resection of the confluence of the superior mesenteric and portal veins has been performed most frequently in the treatment of adenocarcinoma of the pancreas, in view of the reported positive results, but it can also be used in cases of benign pancreatic neolpasias when they are strongly adhered to the mesenteric-portal trunk. Nevertheless, there is no study on the best type of venous grafts for reconstruction of the mesenteric-portal trunk when required. The choice of graft depends on the preference of the surgeon or the institution. This technical note critically discusses the use of the splenic vein as an option for mesenteric-portal trunk reconstruction after gastroduodenopancreatectomy.

Nuss procedure for Pectus excavatum repair: critical appraisal of the evidence

Objective: To evaluate the effectiveness and safety of correction of pectus excavatum by the Nuss technique based on the available scientific evidence.Methods: We conducted an evidence synthesis following systematic processes of search, selection, extraction and critical appraisal. Outcomes were classified by importance and had their quality assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE).Results: The process of selection of items led to the inclusion of only one systematic review, which synthesized the results of nine observational studies comparing the Nuss and Ravitch procedures. The evidence found was rated as poor and very poor quality. The Nuss procedure has increased the incidence of hemothorax (RR = 5.15; 95% CI: 1.07; 24.89), pneumothorax (RR = 5.26; 95% CI: 1.55; 17.92) and the need for reintervention (RR = 4.88; 95% CI: 2.41; 9.88) when compared to the Ravitch. There was no statistical difference between the two procedures in outcomes: general complications, blood transfusion, hospital stay and time to ambulation. The Nuss operation was faster than the Ravitch (mean difference [MD] = -69.94 minutes, 95% CI: -139.04, -0.83).Conclusion: In the absence of well-designed prospective studies to clarify the evidence, especially in terms of aesthetics and quality of life, surgical indication should be individualized and the choice of the technique based on patient preference and experience of the team.

Interference of age and repetition of the same noxious stimulus on hyperalgesia

Pain in animals has been recognized for less than one century. Several authors confirm that animals are capable to process, register and modulate nociceptive stimuli in a very similar way to human kind and there are several evidences registering the impact of pain sensation over vital systems interfering on disease outcome. Nevertheless, despite some evidences that animals, as human beings, can store information from past painful experiences less is known about how this so called pain memory works. The aims of this study were: to evaluate if the response to a painful stimuli differs during different stages of life and if repetition of a same acute stimuli in the same animal interferes with expression of hyperalgesia. Thus, 60 rats were selected and arranged in 3 equal groups: 3 months, 6 months, and 9 months of age. All animals were injected 5% formalin solution in the plantar face of hind paw under volatile general anesthesia. Von Frey filaments were applied at 1h, 24h and 48h after sensitization. Injection was repeated twice with a 30-day interval, each time in a different hind paw. Results showed that younger rats express lower hyperalgesia thresholds in the first stimulation compared to elder animals and that repetition of same stimulus diminishes hyperalgesia thresholds when it begins during infant period and augments hyperalgesia thresholds when it begins during elder ages.

Use of grass carp (Ctenopharyngodon idella) as a biological control agent for submerged aquatic macrophytes

This study aimed to evaluate feed preference and control efficacy of grass carp (Ctenopharyngodon idella) on the aquatic macrophytes Ceratophyllum demersum, Egeria densa and Egeria najas. An experiment was carried out at mesocosms conditions with 2,000 liters capacity and water residence time of 2.8 days. C. demersum, E. densa e E. najas biomasses were offered individually with sixty g and coupled in similar quantities of 30 g of each species, evaluated during 81 days, envolving 6 treatments. (1 - C. demersum, 2 - E. najas, 3 -E. densa, 4 - C. demersum + E. najas, 5 - C. demersum + E. densa and 6 - E. najas + E. densa). When offered individually, E. najas and C. demersum presented the same predation rate by grass carp, which was higher than E. densa predation rate. When plants were tested in pairs, the order of feed preference was C. demersum > E. najas > E. densa. E. najas and C. demersum percentage control ranged from 73 to 83%. No relation between biomass consumption and grass carp body weight gain was observed, probably due to differences in nutritional quality among macrophyte species according to fish necessities. Therefore, it is concluded that the use of grass carp is one excellent technique to control submersed macrophytes in Brazil.

STUDY OF AUTUMN-WINTER WEEDS IN PORTUGAL AND ITS ECOLOGICAL PREFERENCES

ABSTRACTThe conclusion of the dam project located in Alqueva, in Southern Portugal, has resulted in a significant increase of new irrigated areas, since 2006. This has meant that, in recent years, there have been progressive flora changes in farming systems traditionally implemented in the Alentejo region. The present work has analyzed the weed flora in an early stage of these changes, and the impact of environmental factors on the distribution of natural vegetation under Mediterranean climate conditions in the influence area of Alqueva. In 2007, 105 floristic surveys were carried out in autumn-winter crop plots or other soil use, and 264 species were identified. Families with higher expression were: Asteraceae, Poaceae, and Fabaceae. Only three species have been identified in more than half of farms, Avena sterilis, Phalaris minor and Lolium rigidum and they were part of the 15 species that revealed high and very high infestation degrees. Soil texture and extractable phosphorus have been determined as active ecological factors, according to the method of ecological profiles and Mutual Information. Therefore, these factores were those with the greatest influence on the species distribution. L.rigidum distribution showed to be associated with medium soil texture and A.sterilis distribution also showed to be associated with medium and fine soil texture soils, without showing ecological preference by extractable phosphorus. The distribution of P.minorwas not related to the soil texture but showed preference for soils with medium phosphorus content.

Mimosa splendida Barneby (Mimosoideae, Leguminosae) rediscovered in Central Brazil: preliminary studies for conservation of a rare species

The poorly known Mimosa splendida Barneby has been rediscovered in the Chapada dos Veadeiros, Brazil, 105 years after its single record in 1895. Data on its habitat description, demography, reproductive parameters, and geographic range are presented. Preliminary results suggest that the rarity of M. splendida in herbarium collections is associated with a narrow geographic range, and a specialized habitat preference on rocky slopes.

The coastal restinga vegetation of Pará, Brazilian Amazon: a synthesis

The present article reviews studies (some unpublished) of the vegetation of coastal sandy soils (restinga) along the coast of Pará State, northern Brazil. A total of 411 higher plant species are reported; Fabaceae, Poaceae, Cyperaceae, Rubiaceae and Myrtaceae are the most species-rich families. Nearly half of the restinga species (48%) are terrestrial herbs; palms, trees and shrubs account for 39% of the species, the remainder being lianas and epiphytes. Species are frequently wide-spread and occur in coastal areas of Southeastern Brazil as well as at inland sites in the Amazon region. Only two species appear to be exclusively coastal; whereas other species appear to exhibit a preference for sandy soils. Plant assemblages are commonly classified by means of "formations" associated with certain habitats but current data do not allow the description of well-defined plant associations. The species composition at different sites along the Pará coast does not show any clear regional grouping pattern. Seasonal changes in the composition of restinga vegetation are most probably linked to variation in ground water level. Restinga forest is mostly low and open; among the dominant tree species are Humiria balsamifera Aubl., Pouteria ramiflora (Mart.) Radlk., Anacardium occidentale L., Byrsonima crassifolia (L.) Kunth, and Tapirira guianensis Aubl.

Food, mood and health: a neurobiologic outlook

Hippocrates was the first to suggest the healing power of food; however, it was not until the medieval ages that food was considered a tool to modify temperament and mood, although scientific methods as we know them today were not in use at the time. Modern scientific methods in neuroscience began to emerge much later, leading investigators to examine the role of diet in health, including mental well-being, with greater precision. This review shows how short- and long-term forced dietary interventions bring about changes in brain structure, chemistry, and physiology, leading to altered animal behavior. Examples will be presented to show how diets alter brain chemistry, behavior, and the action of neuroactive drugs. Most humans and most animal species examined in a controlled setting exhibit a fairly reproducible pattern of what and how they eat. Recent data suggest that these patterns may be under the neurochemical and hormonal control of the organisms themselves. Other data show that in many instances food may be used unconsciously to regulate mood by seemingly normal subjects as well as those undergoing drug withdrawal or experiencing seasonal affective disorders and obesity-related social withdrawal. We will discuss specific examples that illustrate that manipulation of dietary preference is actually an attempt to correct neurochemical make-up.

Experimental anxiety and the reinforcing effects of ethanol in rats

In order to examine the relationship between anxiety and reinforcing effects of alcohol, drug-naive male Wistar rats weighing 250-300 g were classified as "anxious" and "non-anxious" in the elevated plus-maze test. A conditioned place preference test was then used to investigate the reinforcing effects of ethanol (EtOH) on these animals. On 2 alternate days, groups of "anxious", "non-anxious" and "normal" rats received intraperitoneal (ip) injections of EtOH (0.5, 1.0 or 1.5 g/kg) immediately before a 15-min confinement to the white compartment. On the 2 intervening days the same rats received ip injections of saline before confinement to the opposite compartment. On day 5, a 15-min free-choice test was carried out with no injections. Rats classified as "anxious" showed a significant, though not dose-dependent preference for all doses of ethanol compared to saline-treated animals. These data demonstrate that rats regarded as "anxious" are more sensitive to the reinforcing effects of EtOH than "non-anxious" and "normal" Wistar rats and emphasize the relevance of the basal levels of anxiety of rats when trying to detect the reinforcing effects of EtOH.

Searching for the role of protein phosphatases in eukaryotic microorganisms

Preference for specific protein substrates together with differential sensitivity to activators and inhibitors has allowed classification of serine/threonine protein phosphatases (PPs) into four major types designated types 1, 2A, 2B and 2C (PP1, PP2A, PP2B and PP2C, respectively). Comparison of sequences within their catalytic domains has indicated that PP1, PP2A and PP2B are members of the same gene family named PPP. On the other hand, the type 2C enzyme does not share sequence homology with the PPP members and thus represents another gene family, known as PPM. In this report we briefly summarize some of our studies about the role of serine/threonine phosphatases in growth and differentiation of three different eukaryotic models: Blastocladiella emersonii, Neurospora crassa and Dictyostelium discoideum. Our observations suggest that PP2C is the major phosphatase responsible for dephosphorylation of amidotransferase, an enzyme that controls cell wall synthesis during Blastocladiella emersonii zoospore germination. We also report the existence of a novel acid- and thermo-stable protein purified from Neurospora crassa mycelia, which specifically inhibits the PP1 activity of this fungus and mammals. Finally, we comment on our recent results demonstrating that Dictyostelium discoideum expresses a gene that codes for PP1, although this activity has never been demonstrated biochemically in this organism.