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Search Results: 1 - 10 of 5990 matches for " Horacio Santiago; "
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Agglutinating Activity and Structural Characterization of Scalarin, the Major Egg Protein of the Snail Pomacea scalaris (d’Orbigny, 1832)
Santiago Ituarte, Marcos Sebastián Dreon, Marcelo Ceolin, Horacio Heras
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0050115
Abstract: Apple snail perivitellins are emerging as ecologically important reproductive proteins. To elucidate if the protective functions of the egg proteins of Pomacea canaliculata (Caenogastropoda, Ampullariidae), involved in embryo defenses, are present in other Pomacea species we studied scalarin (PsSC), the major perivitellin of Pomacea scalaris. Using small angle X-ray scattering, fluorescence and absorption spectroscopy and biochemical methods, we analyzed PsSC structural stability, agglutinating activity, sugar specificity and protease resistance. PsSC aggluttinated rabbit, and, to a lesser extent, human B and A erythrocytes independently of divalent metals Ca2+ and Mg2+ were strongly inhibited by galactosamine and glucosamine. The protein was structurally stable between pH 2.0 to 10.0, though agglutination occurred only between pH 4.0 to 8.0 (maximum activity at pH 7.0). The agglutinating activity was conserved up to 60°C and completely lost above 80°C, in agreement with the structural thermal stability of the protein (up to 60°C). PsSC was able to withstand in vitro gastrointestinal digestion, and showed no trypsin inhibition activity. The presence of lectin activity has been reported in eggs of other Pomacea snails, but here we link for the first time, this activity to an apple snail multifunctional perivitellin. This novel role for a snail egg storage protein is different from closely related P.canaliculata defensive proteins.
The Role of the Proteinase Inhibitor Ovorubin in Apple Snail Eggs Resembles Plant Embryo Defense against Predation
Marcos Sebastián Dreon,Santiago Ituarte,Horacio Heras
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015059
Abstract: Fieldwork has thoroughly established that most eggs are intensely predated. Among the few exceptions are the aerial egg clutches from the aquatic snail Pomacea canaliculata which have virtually no predators. Its defenses are advertised by the pigmented ovorubin perivitellin providing a conspicuous reddish coloration. The nature of the defense however, was not clear, except for a screening for defenses that identified a neurotoxic perivitellin with lethal effect on rodents.
Lobulectomía pulmonar toracoscópica: resultados iniciales en pediatría
Martínez Ferro,Marcelo; Vidaurreta,Santiago; Buela,Enrique; Bignon,Horacio;
Archivos argentinos de pediatr?-a , 2010,
Abstract: the objective of the present study consists of revising our initial experience with the use of thoracoscopic surgery for lung resections and their complications. clinical histories and videos, from patients treated surgically at the fundación hospitalaria-private children hospital and cemic universitary hospital from april 2005 to october 2008, were retrospectivelly estudied. eleven female and 9 male patients were included. the median surgical time was 150 min (range: 60-270 min). the median time of chest tube permanence was 3 days (range: 2-10 days). median hospital stay was 15 days (range: 3-29 days). it was concluded that thoracoscopic lung lobectomies are technically feasible and applicable to all paediatric ages; they should be considered as an alternative approach for trained groups.
Hydrokinetic Assessment of the Kvichak River near Igiugig, Alaska, Using a Two-Dimensional Hydrodynamic Model  [PDF]
Horacio Toniolo
Energy and Power Engineering (EPE) , 2012, DOI: 10.4236/epe.2012.46056
Abstract: Two-dimensional hydrodynamic simulations were performed on a monthly basis along 2.5 km of the Kvichak River near Igiugig in southwest Alaska, USA, to estimate flow conditions and to assess the hydrokinetic potential of the river reach. Instantaneous power density function along the computational domain was calculated. Study results indicate that two areas may be suitable for deploying turbines. The best option is located near the town, where the channel is relatively straight. A second possible site is located near the end of the study reach (approximately 2.3 km, along the river, from Lake Illiamna). Monthly-averaged velocities along the thalweg ranged from 1.7 to 2.7 m/s; and from 1.1 to 2 m/s at the upstream and downstream sites, respectively. Similarly, averaged values for the instantaneous power density, reduced by an extraction coefficient, were approximately 1500 and 5500 W/m2 during April and September, respectively, at the upstream site, as well as 400 and 2500 W/m2 for the same months at the downstream site. It was found that a previous resource assessment, which considered cross-sectionally averaged velocities, substantially underestimated the available power density along the river reach. Finally, the importance of having adequate bathymetric data is demonstrated by comparing field measurements with model simulations.
Bed Forms and Sediment Characteristics along the Thalweg on the Tanana River near Nenana, Alaska, USA  [PDF]
Horacio Toniolo
Natural Resources (NR) , 2013, DOI: 10.4236/nr.2013.41003
Abstract:

Sediment sampling and longitudinal river-bottom surveys were conducted along the thalweg on the Tanana River near the city of Nenana, Alaska, USA, to provide basic information for the engineering design requirements of hydrokinetic devices to be deployed in the area. The study reach was located at approximately 64°33'50\"N and 149°04'W. The Tanana is a large glacier-fed river, with open-water flow conditions from May to October. The river presents a single channel in the study area. Granulometric analyses of sediment moving near the riverbed reveals the coexistence of three distinctive types of sediment along the study reach: 1) nearly uniform fine sand; 2) bimodal distributions containing fine sand and medium gravel; and 3) medium gravel. Preliminary relationships between sediment loads and discharge were developed. Dunes with small superimposed dunes were found along the reach. The basic geometric parameters (i.e., wavelength and height) of dunes were measured, and steepness was calculated. In general, dune wavelength increased with increasing discharge. Dune wavelengths ranged from 41 to 67 m, while small-dune wavelengths ranged from 13 to 16 m. Steepness increased slightly with increasing discharge.

 

cGMP-Phosphodiesterase Inhibition Enhances Photic Responses and Synchronization of the Biological Circadian Clock in Rodents
Santiago A. Plano, Patricia V. Agostino, Horacio O. de la Iglesia, Diego A. Golombek
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037121
Abstract: The master circadian clock in mammals is located in the hypothalamic suprachiasmatic nuclei (SCN) and is synchronized by several environmental stimuli, mainly the light-dark (LD) cycle. Light pulses in the late subjective night induce phase advances in locomotor circadian rhythms and the expression of clock genes (such as Per1-2). The mechanism responsible for light-induced phase advances involves the activation of guanylyl cyclase (GC), cGMP and its related protein kinase (PKG). Pharmacological manipulation of cGMP by phosphodiesterase (PDE) inhibition (e.g., sildenafil) increases low-intensity light-induced circadian responses, which could reflect the ability of the cGMP-dependent pathway to directly affect the photic sensitivity of the master circadian clock within the SCN. Indeed, sildenafil is also able to increase the phase-shifting effect of saturating (1200 lux) light pulses leading to phase advances of about 9 hours, as well as in C57 a mouse strain that shows reduced phase advances. In addition, sildenafil was effective in both male and female hamsters, as well as after oral administration. Other PDE inhibitors (such as vardenafil and tadalafil) also increased light-induced phase advances of locomotor activity rhythms and accelerated reentrainment after a phase advance in the LD cycle. Pharmacological inhibition of the main downstream target of cGMP, PKG, blocked light-induced expression of Per1. Our results indicate that the cGMP-dependent pathway can directly modulate the light-induced expression of clock-genes within the SCN and the magnitude of light-induced phase advances of overt rhythms, and provide promising tools to design treatments for human circadian disruptions.
Changes in body composition in lactating adolescent mothers
González,Horacio F; Malpeli,Agustina; Mansur,José L; De Santiago,Soledad; Etchegoyen,Graciela S;
Archivos Latinoamericanos de Nutrición , 2005,
Abstract: we assessed changes in body composition in lactating adolescent mothers living under unfavorable socioeconomic and sanitary conditions. a total of 17 healthy primiparous adolescents under 17 years of age attending the maternity hospital of the city of la plata, argentina, were followed at 4 time points (15 days and 3, 6 and 12 months postpartum) to assess, a) dietary intake, b) practice of physical activity, c) nutritional condition (weight, height, body mass index; bmi; according to age, and body composition by the sum of skinfold measurements), d) characteristics of lactation, and e) growth parameters of the child. the mean age of adolescents was 15.06 ± 0.66 years (mean menarchal age, 11.59 ± 0.80 years). all adolescents breastfed up to 12 months postpartum, and maternal milk covered above 80% the baby intake (mean 7.06 ± 2.54 breast feeds/day). while the daily intake of nutrients by adolescent mothers was constant up to 6 months postpartum, there was a modest decrease in that of proteins, carbohydrates and lipids 15 days and 12 months postpartum. the decrease in energetic intake during the same period was significant (p< 0.05). the practice of physical activity was classified as moderate during the follow-up period. whereas mean basal percent of fat body mass (fbm) was 29.85 ± 2.87, and decreased significantly at 6 (27.2% ± 3.9%; p= 0.02) and 12 (26.1% ± 3.9%; p=0.002) months postpartum, changes in lean body mass (lbm) were not significant. in conclusion, lactating adolescents maintained lbm, whereas weight, fbm and bmi decreased markedly from 3 months postpartum.
Níveis de fósforo digestível para suínos em fase de crescimento
Bünzen, Silvano;Rostagno, Horacio Santiago;Kiefer, Charles;Teixeira, Alexandre de Oliveira;Ribeiro Junior, Valdir;
Revista Brasileira de Zootecnia , 2012, DOI: 10.1590/S1516-35982012000200013
Abstract: this study was carried out to determine the digestible phosphorus requirement for growing swine. seventy crossbred swine (35 castrated males and 35 females), with initial weight of 29.72±1.52 kg were distributed in a completely randomized design with five treatments, seven replicates and two animals (one male and one female) per experimental unit. the experiment lasted 21 days. the treatments were composed of diets formulated with corn and soybean meal, supplemented with dicalcium phosphate, corresponding to five levels of digestible phosphorus (0.19; 0.25; 0.30; 0.35 and 0.40%). for each phosphorus level, limestone was added to maintain the calcium:phosphorus ratio constant. the increase in digestible phosphorus influenced feed intake and weigh gain quadratically, and the maximum values for those parameters were obtained with the levels of 0.32 and 0.31% digestible phosphorus, respectively. there was no effect of digestible phosphorus levels on the feed:gain ratio. the ashes and calcium contents analyzed in the metatarsi were not influenced by digestible phosphorus levels, while the phosphorus content in bone showed linear response. the requirement of digestible phosphorus for pigs fed diets based on corn and soybean meal is 0.31%, corresponding to a daily intake of 5.87 g digestible phosphorus.
Determina??o dos valores energéticos de alguns óleos e gorduras para pintos de corte machos e fêmeas aos 21 dias de idade
Nascif, Carla Cristina Cardoso;Gomes, Paulo Cezar;Albino, Luiz Fernando Teixeira;Rostagno, Horacio Santiago;
Revista Brasileira de Zootecnia , 2004, DOI: 10.1590/S1516-35982004000200014
Abstract: one bioassay was carried out using 21-to32-day old broilers chicks to determine the values of apparent metabolizable energy (ame) and nitrogen-corrected apparent metabolizable energy (amen) of crude soybean oil, corn oil, canola oil, avian fat, coconut fat, swine lard, beef tallow, crude soybean oil + coconut fat and crude soybean oil + beef tallow, both latter in 1:1 proportion. the method of total excreta collection was used for the trials, which lasted 10 days each: the first five days for adaptation and the five remaining days for excreta collection. in the assay, difference was observed among the treatments and between the sexes, with the amen values obtained for the females accounting for 98% of the amen values obtained for the males, on average. the interaction feed x sex showed no difference. the mean values of amen observed for broilers chicks for crude soybean oil, corn oil, canola oil, avian fat, coconut fat, swine lard, beef tallow, crude soybean oil + coconut fat and crude soybean oil + beef tallow, 1:1, were, respectively: 8,273, 8,582, 8,681, 8,511, 7,487, 7,536, 7,227, 8,029 and 8,171 kcal/kg as fed.
Valores de composi??o química e energética de alguns alimentos para aves
D'Agostini, Priscila;Gomes, Paulo Cezar;Albino, Luiz Fernando Teixeira;Rostagno, Horacio Santiago;Sá, Luciano Moraes;
Revista Brasileira de Zootecnia , 2004, DOI: 10.1590/S1516-35982004000100017
Abstract: the experiment was carried out to determine the chemical and the energetic values of eight feedstuffs (corn grain, corn pre-cooked i and ii, canola meal, spray-dried plasma, poultry by-product meal, glucose and corn starch) for birds. to determine the apparent metabolizable energy (ame) and nitrogen corrected apparent (amen) values, the traditional method of total excreta collection was used, with 400 broiler chicks, male and female, 21 days old. a completely randomized design, with ten treatments (eight feedstuffs and two reference diets), and five replications of eight birds per experimental unit, was used. the corn grain and pre-cooked i and ii replaced 40%, and the starch and glucose 20% of the reference diet containing 26% crude protein (cp); the canola meal replaced 40%, and spray-dried plasma and poultry by-products meal 20% of the reference diet containing 18% cp. dry matter - dm (%), cp (%), ame (kcal/kg) e amen (kcal/kg) values were, respectively, for corn grain: 87.72, 7.33, 3,246, and 3,235; for pre-cooked i: 87.75, 7.14, 3,385, and 3,379; for pre-cooked ii: 87.88, 7,34, 3.187 and 3.179; for canola meal: 87,53, 37,89, 1,793 and 1,778; for spray-dried plasma: 90,67, 74,24, 3.503 and 3.474; and for poultry by-product meal: 90.35, 64.98, 4,293 and 4,268. for the glucose and corn starch, only the values of dm (%), ame (kcal/kg) and amen (kcal/kg) were determined, and for the glucose the values were 99.12, 3,170, and 3,168 and for corn starch, 85.52, 3,203, and 3201, respectively.
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