Establishment of a flavor preference in rats: Importance of nursing and weaning experience.

In a study with 36 Sprague-Dawley pups it was found that Ss that experienced garlic flavor during 21 days of nursing (in mother's milk) and for a 5-day period after weaning drank considerably more garlic solution over 12 days of testing than did Ss nursed by water-imbibing mothers and weaned on water. Still other Ss that had garlic either during nursing or after weaning manifested intermediate garlic preferences over these same tests, though the initial intake of garlic was greater in the former condition. The durability of such preferences was demonstrated in a 2nd series of 6 daily tests given 1 mo later when the same ordering of groups recurred. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparative study of conventional instruction and individual programed instruction in the college classroom.

The traditional college classroom teaching method of lecture and assigned readings was compared with an individual programed instructional method utilizing a programed text. 21 pairs of Ss, matched according to sex, age, intelligence test score, and hours of formal training in the biological sciences, were 1st tested upon completion of the physiological portion of an introductory psychology course. They were then retested 6 wk. later. No significant differences were found in performance on Test 1. However, the level of performance on Test 2 was significantly higher for the program-instructed group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnetic ripple diffusion and stable INTOR equilibria

Under conditions representative of ignited tokamak operation, ion energy losses are likely to be dominated by transport due to deviation from toroidal field axisymmetry. This asymmetry, termed ripple, induces several distinct physical processes, all of which lead to enhanced ion thermal conduction above the neoclassical value. The net impact of these processes on ignition dynamics is analyzed for an INTOR-like plasma by means of a 1 1/2-D transport code. The radial shift of the plasma to regions of higher ripple during plasma heating results in a substantial broadening of the window of values of ripple consistent with favorable ignition and burn characteristics and also provides some measure of automatic burn control. Because-limiting processes are also prime candidates for burn control, the profiles obtained from the transport analyses are examined for stability with respect to ideal MHD modes. The MHD-limited value increases as the plasma is heated and in fact in the burn phase approaches the value characteristic of a shape-optimized MHD equilibrium. The sensitivity of the transport and MHD results to the choice of plasma density is examined, and it is found that hot-ion mode operation is precluded for devices such as INTOR unless present estimates of both ripple losses and-limits are highly pessimistic.     

cis-5-Monoenoic fatty acids in some chenopodiaceae seed oils

Methyl esters from seed oils of four Chenopodiaceae species are unusual in that they contain methylcis-5-hexadecenoate (4.6–12%) and methyl 5-octadecenoate (1.1–1.2%). There are indications of small amounts of 18∶2^5,9 and 18∶3^{5, 9, 12} along with unsaturated acids commonly found in seed oils-oleic (14–21%), linoleic (53–57%) and linolenic (3.5–7.8%). Fatty acid composition of the oils was determined by gas chromatography, and positions of the double bonds were established by application of gas chromatography-mass spectrometry to the methoxylated methyl esters. N. Market. Nutr. Res. Div., ARS, USDA.     

The relationship between molecular parameters and polymer distribution and the ability of a polymer to improve the resilience of cotton fabrics

Elastic properties are found to be critical parameters for polymers which improve the wrinkle resistance of cotton fabric. Those molecular factors which results in optimum recovery of a polymer film from distortion (i.e., stretching) are shown to be directly related to the ability to improve fabric wrinkle recovery. Further, those molecular factors which inhibit the tendency of a polymer to form ordered structures allow the inherent flexibility of the polymer to be utilized in storing energy of distortion. This energy is then available, if the polymer is properly distributed on the fabric, to help overcome the fabric's frictional resistance to recovery. The most advantageous distribution of polymer is one in which interfiber and interyarn elastic bridges are formed.     

Improving fracture toughness of dental nanocomposites by interface engineering and micromechanics

The fracture toughness of dental nanocomposites fabricated by various methods of mixing, silanization, and loadings of nanoparticles had been characterized using fatigue-precracked compact-tension specimens. The fracture mechanisms near the crack tip were characterized using atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The near-tip fracture processes in the nanocomposties were identified to involve several sequences of fracture events, including: (1) particle bridging, (2) debonding at the poles of particle/matrix interface, and (3) crack deflection around the particles. Analytical and finite-element methods were utilized to model the observed sequences of fracture events to identify the source of fracture toughness in the dental nanocomposites. Theoretical results indicated that silanization and nanoparticle loadings improved the fracture toughness of dental nanocomposites by a factor of 2-3 through a combination of enhanced interface toughness by silanization, crack deflection, as well as crack bridging. A further increase in the fracture toughness of the nanocomposites can be achieved by increasing the fracture toughness of the matrix, nanofilled particles, or the interface.     

A deficiency of lunatic fringe is associated with cystic dilation of the rete testis

Lunatic fringe belongs to a family of beta1-3 N-acetyltransferases that modulate the affinity of the Notch receptors for their ligands through the elongation of O-fucose moieties on their extracellular domain. A role for Notch signaling in vertebrate fertility has been predicted by the intricate expression of the Notch receptors and their ligands in the oocyte and granulosa cells of the ovary and the spermatozoa and Sertoli cells of the testis. It has been demonstrated that disruption of Notch signaling by inactivation of lunatic fringe led to infertility associated with pleiotropic defects in follicle development and meiotic maturation of oocytes. Lunatic fringe null males were found to be subfertile. Here, we report that gene expression data demonstrate that fringe and Notch signaling genes are expressed in the developing testis and the intratesticular ductal tract, predicting roles for this pathway during embryonic gonadogenesis and spermatogenesis. Spermatogenesis was not impaired in the majority of the lunatic fringe null males; however, spermatozoa were unilaterally absent in the epididymis of many mice. Histological and immunohistochemical analysis of these testes revealed the development of unilateral cystic dilation of the rete testis. Tracer dye experiments confirm a block in the connection between the rete testis and the efferent ducts. Further, the dye studies demonstrated that many lunatic fringe mutant males had partial blocks of the connection between the rete testis and the efferent ducts bilaterally.