Mananas e glucanas em dietas para leitões recém-desmamados

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fibra para cães: efeitos sobre o processo de extrusão, digestibilidade, fermentação microbiana, tempo de retenção intestinal e palatabilidade de rações para cães

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aditivo alternativo, associado ou não ao antimicrobiano, na dieta de leitões recém-desmamados

Pós-graduação em Ciência e Tecnologia Animal - FEIS

Multi-planet extrasolar systems - detection and dynamics

20 years after the discovery of the first planets outside our solar system, the current exoplanetary population includes more than 700 confirmed planets around main sequence stars. Approximately 50% belong to multiple-planet systems in very diverse dynamical configurations, from two-planet hierarchical systems to multiple resonances that could only have been attained as the consequence of a smooth large-scale orbital migration. The first part of this paper reviews the main detection techniques employed for the detection and orbital characterization of multiple-planet systems, from the (now) classical radial velocity (RV) method to the use of transit time variations (TTV) for the identification of additional planetary bodies orbiting the same star. In the second part we discuss the dynamical evolution of multi-planet systems due to their mutual gravitational interactions. We analyze possible modes of motion for hierarchical, secular or resonant configurations, and what stability criteria can be defined in each case. In some cases, the dynamics can be well approximated by simple analytical expressions for the Hamiltonian function, while other configurations can only be studied with semi-analytical or numerical tools. In particular, we show how mean-motion resonances can generate complex structures in the phase space where different libration islands and circulation domains are separated by chaotic layers. In all cases we use real exoplanetary systems as working examples.

Impairment on sperm quality and fertility of adult rats after antiandrogen exposure during prepuberty

This study evaluated the effects of antiandrogen exposure during the prepubertal period on reproductive development and reproductive competence in adults. Male rats were divided into two groups: flutamide, receiving 25 mg/kg/day of flutamide by oral gavage and control, receiving vehicle daily. Dosing continued from PND 21 to 44, and animals were killed on PND 50 or PND 75-80. The epididymis, prostate, vas deferens and seminal vesicle weights were lower in Flutamide group on PND 50, while on PND 80 only seminal vesicle weight was reduced. Fertility assessed by IUI revealed a decrease in the fertility potential in the flutamide-treated adults. Flutamide accelerated sperm transit time through the epididymis, impairing sperm motility and storage. A quantitative analysis of the cauda sperm membrane proteome revealed a few significant changes in protein expression. Thus, exposure to flutamide during the prepubertal period compromises the function of the epididymis along with epididymal sperm quality at adulthood. (C) 2011 Elsevier Inc. All rights reserved.

Current practices in the management of patients with ureteral calculi in the emergency room of a university hospital

OBJECTIVE: Urinary lithiasis is a common disease. The aim of the present study is to assess the knowledge regarding the diagnosis, treatment and recommendations given to patients with ureteral colic by professionals of an academic hospital. MATERIALS AND METHODS: Sixty-five physicians were interviewed about previous experience with guidelines regarding ureteral colic and how they manage patients with ureteral colic in regards to diagnosis, treatment and the information provided to the patients. RESULTS: Thirty-six percent of the interviewed physicians were surgeons, and 64% were clinicians. Forty-one percent of the physicians reported experience with ureterolithiasis guidelines. Seventy-two percent indicated that they use noncontrast CT scans for the diagnosis of lithiasis. All of the respondents prescribe hydration, primarily for the improvement of stone elimination (39.3%). The average number of drugs used was 3.5. The combination of nonsteroidal anti-inflammatory drugs and opioids was reported by 54% of the physicians (i. e., 59% of surgeons and 25.6% of clinicians used this combination of drugs) (p = 0.014). Only 21.3% prescribe alpha blockers. CONCLUSION: Reported experience with guidelines had little impact on several habitual practices. For example, only 21.3% of the respondents indicated that they prescribed alpha blockers; however, alpha blockers may increase stone elimination by up to 54%. Furthermore, although a meta-analysis demonstrated that hydration had no effect on the transit time of the stone or on the pain, the majority of the physicians reported that they prescribed more than 500 ml of fluid. Dipyrone, hyoscine, nonsteroidal anti-inflammatory drugs, and opioids were identified as the most frequently prescribed drug combination. The information regarding the time for the passage of urinary stones was inconsistent. The development of continuing education programs regarding ureteral colic in the emergency room is necessary.

Why do arms extract less oxygen than legs during exercise?

[EN] To determine whether conditions for O2 utilization and O2 off-loading from the hemoglobin are different in exercising arms and legs, six cross-country skiers participated in this study. Femoral and subclavian vein blood flow and gases were determined during skiing on a treadmill at approximately 76% maximal O2 uptake (V(O2)max) and at V(O2)max with different techniques: diagonal stride (combined arm and leg exercise), double poling (predominantly arm exercise), and leg skiing (predominantly leg exercise). The percentage of O2 extraction was always higher for the legs than for the arms. At maximal exercise (diagonal stride), the corresponding mean values were 93 and 85% (n = 3; P < 0.05). During exercise, mean arm O2 extraction correlated with the P(O2) value that causes hemoglobin to be 50% saturated (P50: r = 0.93, P < 0.05), but for a given value of P50, O2 extraction was always higher in the legs than in the arms. Mean capillary muscle O2 conductance of the arm during double poling was 14.5 (SD 2.6) ml.min(-1).mmHg(-1), and mean capillary P(O2) was 47.7 (SD 2.6) mmHg. Corresponding values for the legs during maximal exercise were 48.3 (SD 13.0) ml.min(-1).mmHg(-1) and 33.8 (SD 2.6) mmHg, respectively. Because conditions for O2 off-loading from the hemoglobin are similar in leg and arm muscles, the observed differences in maximal arm and leg O2 extraction should be attributed to other factors, such as a higher heterogeneity in blood flow distribution, shorter mean transit time, smaller diffusing area, and larger diffusing distance, in arms than in legs.

Muscular and pulmonary O2 uptake kinetics during moderate- and high-intensity sub-maximal knee-extensor exercise in humans

[EN] The purpose of this investigation was to determine the contribution of muscle O(2) consumption (mVO2) to pulmonary O(2) uptake (pVO2) during both low-intensity (LI) and high-intensity (HI) knee-extension exercise, and during subsequent recovery, in humans. Seven healthy male subjects (age 20-25 years) completed a series of LI and HI square-wave exercise tests in which mVO2 (direct Fick technique) and pVO2 (indirect calorimetry) were measured simultaneously. The mean blood transit time from the muscle capillaries to the lung (MTTc-l) was also estimated (based on measured blood transit times from femoral artery to vein and vein to artery). The kinetics of mVO2 and pVO2 were modelled using non-linear regression. The time constant (tau) describing the phase II pVO2 kinetics following the onset of exercise was not significantly different from the mean response time (initial time delay + tau) for mVO2 kinetics for LI (30 +/- 3 vs 30 +/- 3 s) but was slightly higher (P < 0.05) for HI (32 +/- 3 vs 29 +/- 4 s); the responses were closely correlated (r = 0.95 and r = 0.95; P < 0.01) for both intensities. In recovery, agreement between the responses was more limited both for LI (36 +/- 4 vs 18 +/- 4 s, P < 0.05; r = -0.01) and HI (33 +/- 3 vs 27 +/- 3 s, P > 0.05; r = -0.40). MTTc-l was approximately 17 s just before exercise and decreased to 12 and 10 s after 5 s of exercise for LI and HI, respectively. These data indicate that the phase II pVO2 kinetics reflect mVO2 kinetics during exercise but not during recovery where caution in data interpretation is advised. Increased mVO2 probably makes a small contribution to during the first 15-20 s of exercise.

New discotic liquid crystals based on large polycyclic aromatic hydrocarbons as materials for molecular electronics

A series of new columnar discotic liquid crystalline materials based on the superphenalene (C96) core has been synthesized by oxidative cyclodehydrogenation with iron(III) chloride of suitable three-dimensional oligophenylene precursors. These compounds were investigated by means of differential scanning calorimetry (DSC), polarized optical microscopy (POM) and wide angle X-ray scattering (WAXS), and showed highly ordered supramolecular arrays and mesophase behavior over a broad temperature range. Good solubility, through the introduction of long alkyl chains, and the fact that these new superphenalene derivatives were found to be liquid crystalline at room temperature enabled the formation of highly ordered films (using the zone-casting technique), a requirement for application in organic electronic devices. The one-dimensional, intracolumnar charge carrier mobilities of superphenalene derivatives were determined using the pulse-radiolysis time-resolved microwave conductivity technique (PR-TRMC). Electrical properties of different C96-C12 architectures on mica surfaces were examined by using Electrostatic Force Microscopy (EFM) and Kelvin Probe Force Microscopy (KPFM). Hexa-peri-hexabenzocoronene (C42) derivatives substituted at the periphery with six branched alkyl ether chains were also synthesized. It was found that the introduction of ether groups within the side chains enhances the affinity of the discotic molecules towards polar surfaces, resulting in homeotropic self-assembly (as shown by POM and 2D-WAXS) when the compounds are processed from the isotropic state between two surfaces. A new, insoluble, superphenalene building block bearing six reactive sites was prepared, and was further used for the preparation of dendronized superphenalenes with bulky dendritic substituents around the core. UV/Vis and fluorescence experiments suggest reduced π-π stacking of the superphenalene cores as a result of steric hindrance between the peripheral dendritic units. A new family of graphitic molecules with partial ”zig-zag” periphery has been established. The incorporation of ”zig-zag” edges was shown to have a strong influence on the electronic properties of the new molecules (as studied by solution and solid-state UV/Vis, and fluorescence spectroscopy), leading to a significant bathochromic shift with respect to the parent PAHs (C42 and C96). The reactivity of the additional double bonds was examined. The attachment of long alkyl chains to a ”zig-zag” superphenalene core afforded a new, processable, liquid crystalline material.

Entwicklung und Charakterisierung eines Laserablationsmassenspektrometers zur Echtzeit-Analyse von atmosphärischen Aerosolpartikeln

Das Aerosolmassenspektrometer SPLAT (Single Particle Laser Ablation Time-of-Flight Mass Spectrometer) ist in der Lage, die Größe einzelner Aerosolpartikel in einem Größenbereich von 0,3 µm bis 3 µm zu bestimmen und gleichzeitig chemisch zu analysieren. Die Größenbestimmung erfolgt durch Streulichtmessung und Bestimmung der Flugzeit der Partikel zwischen zwei kontinuierlichen Laserstrahlen. Durch Kalibrationsmessungen kann auf den aerodynamischen Durchmesser der Partikel geschlossen werden. Kurzzeitig nach der Streulichtdetektion werden die Partikel durch einen hochenergetischen gepulsten UV-Laser verdampft und ionisiert. Die Flugzeit der Partikel zwischen den kontinuierlichen Laserstrahlen wird dazu benutzt, die Ankunftszeit der Partikel in der Ionenquelle zu berechnen und den UV-Laserpuls zu zünden. Die entstandenen Ionen werden in einem bipolaren Flugzeitmassen¬spektrometer nachgewiesen. Durch die Laserablation/Ionisation ist das SPLAT in der Lage, auch schwer verdampfbare Komponenten des atmosphärischen Aerosols - wie etwa Minerale oder Metalle - nachzuweisen. Das SPLAT wurde während dieser Arbeit vollständig neu entwickelt und aufgebaut. Dazu gehörten das Vakuum- und Einlasssystem, die Partikeldetektion, die Ionenquelle und das Massen-spektrometer. Beim Design des SPLAT wurde vor allem auf den späteren Feldeinsatz Wert gelegt, was besondere Anforderungen an Mechanik und Elektronik stellte. Die Charakterisierung der einzelnen Komponenten sowie des gesamten Instruments wurde unter Laborbedingungen durchgeführt. Dabei wurde u.a. Detektionseffizienzen des Instruments ermittelt, die abhängig von der Größe der Partikel sind. Bei sphärischen Partikeln mit einem Durchmesser von 600 nm wurden ca. 2 % der Partikel die in das Instrument gelangten, detektiert und chemisch analysiert. Die Fähigkeit zum Feldeinsatz hat das SPLAT im Februar/März 2006 während einer internationalen Messkampagne auf dem Jungfraujoch in der Schweiz bewiesen. Auf dieser hochalpinen Forschungsstation in einer Höhe von ca. 3580 m fand das SPLAT mineralische und metallische Komponenten in den Aerosolpartikeln. Das SPLAT ist ein vielfältig einsetzbares Instrument und erlaubt vor allem in Kombination mit Aerosolmassenspektrometern, die mit thermischer Verdampfung und Elektronenstoßionisation arbeiten, einen Erkenntnisgewinn in der Analytik atmosphärischer Aerosolpartikel.

Modelling, diagnostics and experimental analysis of plasma assisted processes for material treatment

This work presents results from experimental investigations of several different atmospheric pressure plasmas applications, such as Metal Inert Gas (MIG) welding and Plasma Arc Cutting (PAC) and Welding (PAW) sources, as well as Inductively Coupled Plasma (ICP) torches. The main diagnostic tool that has been used is High Speed Imaging (HSI), often assisted by Schlieren imaging to analyse non-visible phenomena. Furthermore, starting from thermo-fluid-dynamic models developed by the University of Bologna group, such plasma processes have been studied also with new advanced models, focusing for instance on the interaction between a melting metal wire and a plasma, or considering non-equilibrium phenomena for diagnostics of plasma arcs. Additionally, the experimental diagnostic tools that have been developed for industrial thermal plasmas have been used also for the characterization of innovative low temperature atmospheric pressure non equilibrium plasmas, such as dielectric barrier discharges (DBD) and Plasma Jets. These sources are controlled by few kV voltage pulses with pulse rise time of few nanoseconds to avoid the formation of a plasma arc, with interesting applications in surface functionalization of thermosensitive materials. In order to investigate also bio-medical applications of thermal plasma, a self-developed quenching device has been connected to an ICP torch. Such device has allowed inactivation of several kinds of bacteria spread on petri dishes, by keeping the substrate temperature lower than 40 degrees, which is a strict requirement in order to allow the treatment of living tissues.

Skeletal muscle (1) H MRSI before and after prolonged exercise. II. visibility of free carnitine

Carnitine (Car) buffers excess acetyl-CoA through the formation of acetylCar (AcCar). AcCar's acetyl group (AG-AcCar) gives rise to a peak at 2.13 ppm in ¹H MR spectra of skeletal muscle, whereas the trimethylammonium (TMA) groups of both, AcCar and Car, are thought to contribute to the TMA peak at 3.23 ppm. Surprisingly, in previous studies both resonances, AG-AcCar and TMA, increased after exercise. The aim of this study was to assess if the exercise-related TMA increase correlated with AcCar production. Magnetic resonance spectroscopic imaging (pulse repetition time/echo time = 1200/35 ms) was performed before and after prolonged exercise in the lower leg and thigh of eight runners and eight cyclists, respectively. TMA and AG-AcCar increased after exercise (P < 0.001). TMA's increase correlated with the AG-AcCar increase (R² = 0.73, P < 0.001, lower leg; R² = 0.28, P < 0.001, thigh). The correlation of ΔTMA with ΔAG-AcCar suggests that the TMA increase is due to AcCar formation. As total Car (Car + AcCar) remains unchanged with exercise, these findings suggest that the contribution of free Car to the TMA peak is limited and, therefore, is partly invisible in muscle ¹H MR spectra. This indicates that the biochemically relevant cytosolic content of free Car is considerably lower than the overall concentration determined by radioisotopic assays, a potentially important result with respect to regulation of substrate oxidation.

Bowel function remains subjectively unchanged after ileal resection for construction of continent ileal reservoirs

Construction of a continent catheterizable urinary reservoir or an orthotopic bladder substitute requires substantial bowel resection, which can cause changes in bowel transit time. The reported incidence of chronic diarrhea after ileocecal resection is about 20%. Studies assessing bowel function after resection of 55-60 cm of ileum without compromising the ileocecal valve are scarce, and long-term results have not been reported.

Detection of regional blood perfusion changes in epileptic seizures with dynamic brain perfusion CT--a pilot study

BACKGROUND AND PURPOSE: Perfusion CT (P-CT) is used for acute stroke management, not, however, for evaluating epilepsy. To test the hypothesis that P-CT may identify patients with increased regional cerebral blood flow during subtle status epilepticus (SSE), we compared P-CT in SSE to different postictal conditions. METHODS: Fifteen patients (mean age 47 years, range 21-74) underwent P-CT immediately after evaluation in our emergency room. Asymmetry indices between affected and unaffected hemispheres were calculated for regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and mean transit time (MTT). Regional perfusion changes were compared to EEG findings. RESULTS: Three patients in subtle status epilepticus (group 1) had increased regional perfusion with electro-clinical correlate. Six patients showed postictal slowing on EEG corresponding to an area of regional hypoperfusion (group 2). CT and EEG were normal in six patients with a first epileptic seizure (group 3). Cluster analysis of asymmetry indices separated SSE from the other two groups in all three parameters, while rCBF helped to distinguish between chronic focal epilepsies and single events. CONCLUSION: Preliminary results indicate that P-CT may help to identify patients with SSE during emergency workup. This technique provides important information to neurologists or emergency physicians in the difficult clinical differential diagnosis of altered mental status due to subtle status epilepticus.

Decreasing gut wall glucose as an early marker of impaired intestinal perfusion

OBJECTIVE: The aim of this study was to assess the microcirculatory and metabolic consequences of reduced mesenteric blood flow. DESIGN: Prospective, controlled animal study. SETTING: The surgical research unit of a university hospital. SUBJECTS: A total of 13 anesthetized and mechanically ventilated pigs. INTERVENTIONS: Pigs were subjected to stepwise mesenteric blood flow reduction (15% in each step, n = 8) or served as controls (n = 5). Superior mesenteric arterial blood flow was measured with ultrasonic transit time flowmetry, and mucosal and muscularis microcirculatory perfusion in the small bowel were each measured with three laser Doppler flow probes. Small-bowel intramucosal Pco2 was measured by tonometry, and glucose, lactate (L), and pyruvate (P) were measured by microdialysis. MEASUREMENTS AND MAIN RESULTS: In control animals, superior mesenteric arterial blood flow, mucosal microcirculatory blood flow, intramucosal Pco2, and the lactate/pyruvate ratio remained unchanged. In both groups, mucosal blood flow was better preserved than muscularis blood flow. During stepwise mesenteric blood flow reduction, heterogeneous microcirculatory blood flow remained a prominent feature (coefficient of variation, approximately 45%). A 30% flow reduction from baseline was associated with a decrease in microdialysis glucose concentration from 2.37 (2.10-2.70) mmol/L to 0.57 (0.22-1.60) mmol/L (p < .05). After 75% flow reduction, the microdialysis lactate/pyruvate ratio increased from 8.6 (8.0-14.1) to 27.6 (15.5-37.4, p < .05), and arterial-intramucosal Pco2 gradients increased from 1.3 (0.4-3.5) kPa to 10.8 (8.0-16.0) kPa (p < .05). CONCLUSIONS: Blood flow redistribution and heterogeneous microcirculatory perfusion can explain apparently maintained regional oxidative metabolism during mesenteric hypoperfusion, despite local signs of anaerobic metabolism. Early decreasing glucose concentrations suggest that substrate supply may become crucial before oxygen consumption decreases.