ANP gene expression in rat hearts during hypoxia

The relationships between muscle capillarization, estimated O2 diffusion distance from capillary to mitochondria, and O2 uptake (VO2) kinetics were studied in 11 young (mean age, 25.9 yr) and 9 old (mean age, 66.0 yr) adults. VO2 kinetics were determined by calculating the time constants (tau) for the phase 2 VO2 adjustment to and recovery from the average of 12 repeats of a 6-min, moderate-intensity plantar flexion exercise. Muscle capillarization was determined from cross sections of biopsy material taken from lateral gastrocnemius. Young and old groups had similar VO2 kinetics (tau VO2-on = 44 vs. 48 s; tau VO2-off = 33 vs. 44 s, for young and old, respectively), muscle capillarization, and estimated O2 diffusion distances. Muscle capillarization, expressed as capillary density or average number of capillary contacts per fiber/average fiber area, and the estimates of diffusion distance were significantly correlated to VO2-off kinetics in the young (r = -0.68 to -0.83; P < 0.05). We conclude that 1) capillarization and VO2 kinetics during exercise of a muscle group accustomed to everyday activity (e.g., walking) are well maintained in old individuals, and 2) in the young, recovery of VO2 after exercise is faster, with a greater capillary supply over a given muscle fiber area or shorter O2 diffusion distances.     

Effects of calcining conditions on the microstructure of sugar cane waste ashes (SCWA): Influence in the pozzolanic activation

In this paper a study of calcining conditions on the microstructural features of sugar cane waste ash (SCWA) is carried out. For this purpose, some microparticles (<90 μm) of sugar cane straw ash and sugar cane bagasse ash of samples calcined at 800 °C and 1000 are studied by combining the bright field and the dark field images with the electron diffraction patterns in the transmission electron microscopy (TEM). It is appreciated that the morphology and texture of these microparticles change when silicon or calcium are present. Furthermore, it is observed that iron oxide (magnetite Fe₃O₄) is located in the calcium-rich particles.The microstructural information is correlated with the results of a kinetic–diffusive model that allows the computing of the kinetic parameters of the pozzolanic reaction (mainly the reaction rate constant). The results show that the sugar cane wastes ash calcined at 800 and 1000 °C have properties indicative of high pozzolanic activity. The X-ray diffraction patterns, the TEM images and the pozzolanic activity tests show the influence of different factors on the activation of these ashes.     

Counterconditioning of an overshadowed cue attenuates overshadowing.

In 3 Pavlovian conditioned lick-suppression experiments, rats received overshadowing treatment with a footshock unconditioned stimulus such that Conditioned Stimulus (CS) A overshadowed CS X. Subjects that subsequently received CS X paired with an established signal for saccharin (CS B) exhibited less overshadowing of the X–footshock association than subjects that did not receive the X–B pairings (Experiment 1). Experiment 2 replicated this effect and controlled for some additional alternative accounts of the phenomenon. In Experiment 3, this recovery from overshadowing produced by counterconditioning CS X was attenuated if CS B was massively extinguished prior to counterconditioning. These results are more compatible with models of cue competition that emphasize differences in the expression of associations than those that emphasize differences in associative acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An Electrometer Amplifier with Low Input Capacitance and Large Input Dynamic Range

An electrometer amplifier has been designed for biological research with the following data: input resistance larger than 1012; input current 10-12 A; low input capacitance; and an input dynamic range from 0 to ± 7 v. The input stage consists of JFET.     

Weathering of vegetable fibre-clinker free cement composites

Ground iron blast-furnace slag (BFS) activated by a mixture of gypsum and hydrated lime was examined as an alternative binder for fibre-cement mortars produced by a low energy consumption method. Brazilian fibrous wastes from sisal and banana crops and also from a eucalyptus pulp mill were chosen for reinforcement. The composite preparation followed conventional mixing, ordinary vibration and wet chamber curing for the seven initial days. The composites achieved a modulus of rupture of up to 3.92 MPa at an age of 28 days. Flexural toughness was at least 40% superior to that of the non-reinforced matrix. Microstructure analyses presented additional information on the understanding of fibre-matrix interaction and its correlation with composites macrostructural behaviour. The effects of natural weathering on the performance of fibre-cement composites were investigated in comparison with accelerated ageing tests. Sixteen months of exposure in tropical climate conditions caused the severest decay in the loading capacity and composite embrittlement, in spite of the absence of superficial darkening or visible cracks. The reduction of the mechanical properties was attributed to a combination of different processes, such as matrix carbonation, fibre mineralization and transition zone degeneration.

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Résumé Les laitiers de haut foumeau broyés et activés par un mélange de phosphogypse et de chaux hydratée ont été examinés comme un liant alternatif pour des mortiers en fibre-ciment produits par une méthode de basse consommation d'énergie. Des déchets, tels que les fibres de récoltes du sisal et de la banane et aussi ceux de la pate à papier d'eucalyptus, ont été choisis comme renforcement. Le mélange du composite a suivi le processus conventionnel de malaxage, vibration et cure en chambre humide pendant sept jours. Les composites ont présenté des modules de rupture jusqu'à 3,92 MPa après 28 jours. La tenacité en flexion a été au moins 40% supérieure à celle de la matrice non renforcée. Une analyse de la microstructure a exposé des informations supplémentaires sur la compréhension du mécanisme d'interaction de la fibre-matrice et sa corrélation avec le comportement macrostructural des composites. Les performances des composites fibres/ciment ont été étudiées sous des conditions climatiques naturelles et par des essais de vieillissement accéléré. Le stockage du matériau sous des conditions tropicales, pendant seize mois, a provoqué les pertes les plus sévères concernant la capacité de résistance et la fragilisation du composite, malgré l'absence de noircissement superficiel ou de fissures visibles. La réduction des performances mécaniques a été attribuée à une combinaison de différents processus, comme la carbonatation de la matrice, la pétrification de la fibre et la dégénérescence de la zone de transition.

     

The effects of high pressure processing on pork quality, palatability, and further processed products

The objective was to evaluate high pressure processing (HPP) on postmortem metabolism and pork quality. Six pigs were randomly selected immediately after slaughter. After splitting, one side was randomly designated for HPP of 215 MPa for 15 s with water temperature at 33 °C and the other side (non-pressure treated) served as the control. Chilled sides were fabricated into loins, boneless picnic, boneless Boston butt, and ham. Samples were cut from the loin, inside portion of the ham and cushion (M. triceps brachii). Pork quality, lipid oxidation, connective tissue solubility, protein functionality, sensory analysis, and processed characteristics of restructured hams were evaluated. HPP partially inhibits postmortem metabolism, indicated by lower muscle lactate levels and higher ultimate pH values. Cook and drip loss were both reduced in HPP treated muscles compared to controls. HPP treated sides were more tender than controls. Collagen content was not different between HPP and control groups.