Endogenous AVP systems regulate oral behavior in the rat fetus: Neuropeptide systems as ontogenetic adaptations.

Pharmacological manipulation of V? receptors in rostral and caudal brain regions alters perioral responsiveness in the E20 rat fetus. Blockade of caudal V? receptors or activation of rostral V? receptors reduces fetal responsiveness to perioral cutaneous stimulation. Activation of caudal V? receptors or blockade of rostral V? receptors increases fetal responsiveness to perioral stimulation, including oral capture and grasping of an artificial nipple. These results suggest that V? receptor-containing neurons regulate perioral responsiveness in the E20 rat fetus and that the 2 populations of neurons exhibit functional differences. The caudal part of the arginine–8-vasopressin (AVP) system increases whereas the rostral part decreases responsiveness to different types of perioral stimuli. The neuropeptide AVP may affect suckling behavior immediately after birth by regulating perioral sensory responsiveness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Porous structure and sorption properties of nitrogen-containing activated carbon

Nitrogen-containing activated carbon (NAC) derived from ammonium humates was produced and its porous structure (specific surface, pore volume) investigated. The NAC is mesoporous activated carbon with surface area of 557 m²/g and containing 2.4 wt.% of nitrogen. Sorption characteristics (sorption activity of iodine, methylene blue, benzene and metal ions Cu²⁺ and Pb²⁺) of NAC are compared with activated charcoal and BAU-A.     

Rapid and robust olfactory conditioning with milk before suckling experience: Promotion of nipple attachment in the newborn rat.

An olfactory conditioning paradigm tested the hypothesis that newborn rats are able to learn about events associated with their first experience with milk as early as 3–5 hr after birth. Exposure to lemon odor (conditioned stimulus, [CS]) paired with intraoral milk infusions (unconditioned stimulus, [US]) resulted in strong conditioning: In the presence of the CS, sustained attachment occurred to an empty nipple as if it provided milk, whereas pups in control conditions showed little attachment. A single CS–US pairing was sufficient for strong conditioning, which was evident with a trace interval as long as 60 s. Conditioning was robust enough to promote attachment to a nipple providing saline, which is aversive to the newborn rat, and comparably strong conditioning occurred with sucrose or saccharin as the US. These findings suggest that olfactory conditioning has the potential to modify suckling behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Y-Procedure methodology for the interpretation of transient kinetic data: Analysis of irreversible adsorption

This paper deals with the analysis of transient kinetic data obtained in the Thin-Zone (TZ) configuration of the Temporal Analysis of Products (TAP) reactor. The Y-procedure that reconstructs the reaction rate and gas composition in the catalytic zone with no assumptions on the reaction mechanism (Yablonsky et al., 2007) was applied to irreversible adsorption with coverage-dependent kinetic coefficients. We have used the Y-Procedure analysis to develop a novel framework for the interpretation of non-steady-state kinetic data. This framework was illustrated by multiple numerical examples concerning irreversible adsorption, and by experimental data corresponding to oxygen adsorption on polycrystalline platinum. The total concentration of active sites was estimated as . It was found that for the surface coverage up to 0.8, kinetics followed the dissociative adsorption model with an intrinsic adsorption constant of . Kinetic parameters estimated via the Y-procedure agreed well with the values obtained via the moment analysis. The methodology developed in this paper will guide the systematic application of the Y-Procedure analysis to more complex catalytic systems.     

Ethanol steam reforming over Ni–Fe-based hydrotalcites: Effect of iron content and reaction temperature

Ethanol steam reforming has been evaluated over nickel–iron based hydrotalcite-like compounds with Ni/Fe molar ratios of 1 and 0.5. Calcined materials have been characterized by XRD, TEM, BET and TPR. The introduction of iron leads to the formation of a mixture of Ni(Fe)O_x and spinel phase upon calcination, which results in variations of structural and catalytic properties. With a Ni/Fe ratio of 1, a remarkable improvement in catalytic activity as well as selectivity to hydrogen is observed with respect to the catalyst with Ni/Fe ratio of 0.5. This is due to the enhanced nickel dispersion, the high surface area, and small Ni⁰ crystallite size over the Ni(Fe)O_x + NiFe₂O₄ mixture. However, a further increase in iron content leads to the formation of a low surface area spinel phase (NiFe₂O₄), which results in lower activity and faster deactivation in the reaction through Ni⁰ sintering. The effect of reaction temperature has been evaluated over the most active catalyst (Ni/Fe = 1).     

Bile acid and very low density lipoprotein production by cultured hepatocytes from hypo- orhyperresponsive rabbits fedcholesterol

Two groups of rabbits, either hyperresponsive or hyporesponsive to dietary cholesterol, wereselected after ten weeks of cholesterol feeding (0.2 g cholesterol/kg body weight per day). Bile acids and very low density lipoprotein (VLDL) production were determined in primary hepatocyte cultures from control, hyper- and hyporesponsive rabbits. Free cholesterol and cholesteryl ester contents in hepatocytes of the hyperresponsive rabbits was significantly increased. In contrast, lipid composition in hepatocytes of the hyporesponders was similar to that of control cells. Cholic acid was the predominant bile acid in the culture medium of hepatocytes together with small amounts of chenodeoxycholic and deoxycholic acids. The rate of cholic acid production by hepatocytes in the hyporesponsive group was two times higher than that in the hyperresponsive group. Bile acid production by control hepatocytes was slightly higher than in the hyperresponsive group. In contrast, secretion of VLDL cholesteryl ester was significantly increased by hepatocytes of the hyperresponsive rabbits. Similar differences, in bile acid production were found between hypo- and hyperresponsive rabbits selected after five days of cholesterol feeding and subsequent maintenance on a low cholesterol diet for a period of one month. The results suggest that the increased rate of bile acid production could contribute to the apparent resistance of hyporesponders to the atherogenic diet.     

Olfactory aversive conditioning in the newborn (3-hr-old) rat impairs later suckling for water and milk.

An olfactory conditioning paradigm tested whether newborn rats can acquire a conditioned aversion to olfactory events associated with their first postnatal meal 3-5 hr after birth. Exposure to lemon odor (conditioned stimulus [CS]) paired with intraoral infusions of 0.1% quinine (unconditioned stimulus) resulted in explicit conditioning. Responsiveness to a surrogate nipple providing water in the presence of the CS was significantly lower than the 3 control conditions. The conditioning dramatically suppressed responsiveness to a surrogate nipple providing milk, which normally is expressed voraciously in terms of sustained nipple attachment and milk intake. These findings suggest that as early as 3-5 hr after birth newborn rats are capable of aversive conditioning to odors in the context of suckling behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conservative Models and Numerical Methods for Compressible Two-Phase Flow

The paper presents the computational framework for solving hyperbolic models for compressible two-phase flow by finite volume methods. A hierarchy of two-phase flow systems of conservation-form equations is formulated, including a general model with different phase velocities, pressures and temperatures; a simplified single temperature model with equal phase temperatures; and an isentropic model. The solution of the governing equations is obtained by the MUSCL-Hancock method in conjunction with the GFORCE and GMUSTA fluxes. Numerical results are presented for the water faucet test case, the Riemann problem with a sonic point and the water-air shock tube test case. The effect of the pressure relaxation rate on the numerical results is also investigated.     

All-Solid-State Electro-Chemo-Mechanical Actuator Operating at Room Temperature

Dimensional change in a solid due to electrochemically driven compositional change is termed electro-chemo-mechanical (ECM) coupling. This effect causes mechanical instability in Li-ion batteries and solid oxide fuel cells. Nevertheless, it can generate considerable force and deformation, making it attractive for mechanical actuation. Here a Si-compatible ECM actuator in the form of a 2 mm diameter membrane is demonstrated. Actuation results from oxygen ion transfer between two 0.1  µ m thick Ti oxide\Ce_0.8Gd_0.2O_1.9 nanocomposite layers separated by a 1.5  µ m thick Ce_0.8Gd_0.2O_1.9 solid electrolyte. The chemical reaction responsible for stress generation is electrochemical oxidation/reduction in the composites. Under ambient conditions, application of 5 V DC produces actuator response within seconds, generating vertical displacement of several µm with calculated stress ≈ 3.5 MPa. The membrane actuator preserves its final mechanical state for more than 1 h following voltage removal. These characteristics uniquely suit ECM actuators for room temperature applications in Si-integrated microelectromechanical systems.     

Class-based feature matching across unrestricted transformations

We develop a novel method for class-based feature matching across large changes in viewing conditions. The method is based on the property that when objects share a similar part, the similarity is preserved across viewing conditions. Given a feature and a training set of object images, we first identify the subset of objects that share this feature. The transformation of the feature's appearance across viewing conditions is determined mainly by properties of the feature, rather than of the object in which it is embedded. Therefore, the transformed feature will be shared by approximately the same set of objects. Based on this consistency requirement, corresponding features can be reliably identified from a set of candidate matches. Unlike previous approaches, the proposed scheme compares feature appearances only in similar viewing conditions, rather than across different viewing conditions. As a result, the scheme is not restricted to locally planar objects or affine transformations. The approach also does not require examples of correct matches. We show that by using the proposed method, a dense set of accurate correspondences can be obtained. Experimental comparisons demonstrate that matching accuracy is significantly improved over previous schemes. Finally, we show that the scheme can be successfully used for invariant object recognition.