The cholinergic agent physostigmine enhances short-term-memory-based performance in the developing rat.

There are age-related differences in the rat's short-term memory processes. Rats 24–25 days old are 90% correct when the delay interval separating the forced run and choice run of a trial is either 10 or 30 s, but they perform at chance when the delay interval is 60 s. In contrast, the choice performance of 30-day-old rats remains constant across all delay intervals. It is reported that the cholinergic agent physostigmine dramatically improved the short-term-memory-based performance of rats 24–25 days old such that they displayed no loss in choice accuracy even when the delay interval was 60 s. No such enhanced performance was seen in rats treated with neostigmine, a peripherally acting anticholinesterase. The results support the hypothesis that postnatal maturational differences in central cholinergic systems may contribute to age-related differences in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Still necessary to state the obvious: Comment on Alessi, Roll, Reilly, and Johanson (2002).

S. M. Alessi, J. M. Roll, M. P. Reilly, and C.-E. Johanson's (see record 2002-12827-002) conclusions seemed to the author to unnecessarily state the obvious that the determinants of drug effects and self-administration are not reducible to events within the body. On reflection, however, the author realized that this conclusion is not obvious to many individuals in the broader scientific, professional, and political environment that surrounds the behavioral pharmacology scientific community. Educating these individuals about the concepts, methods, data, and applied implications of behavioral pharmacology is of paramount importance, and one way to do this is to continue to state the obvious. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of temporal information in the regularization of theinverse problem of electrocardiography

The inverse problem of electrocardiography is solved in order to reconstruct electrical events within the heart from information measured noninvasively on the body surface. These electrical events can be deduced from measured epicardial potentials; therefore, a noninvasive method of recovering epicardial potentials from body surface data is useful in clinical and experimental work. The ill-posed nature of this problem necessitates the use of regularization in the solution procedure. Inversion using Tikhonov zero-order regularization, a quasi-static method, had been employed previously and was able to reconstruct, with relatively good accuracy, important events in cardiac excitation (maxima, minima, etc.). Taking advantage of the fact that the process of cardiac excitation is continuous in time, one can incorporate information from the time progression of excitation in the regularization procedure using the Twomey technique. Methods of this type were tested on data obtained from a human-torso tank in which a beating canine heart was placed in the correct human anatomical position. The results show a marked improvement in the inverse solution when these temporal methods are used, and demonstrate that important physiological events (e.g., right ventricular breakthrough) not detected by the quasi-static approach, are reconstructed using these methods. In addition, the results indicate that as the time interval between sampled maps is reduced, the quality of the solutions that use this temporal regularization is greatly improved.     

Study of the water uptake of polyamide 46 based copolymers by magnetic resonance imaging relaxometry

Magnetic resonance imaging (MRI), NMR relaxometry, thermal analysis and gravimetrical experiments are performed to study the water absorption by neat PA46 and copolymers of PA46 and PA4n (PA46-co-PA4n) with 4 mol% n=8, 12 and 16. The observed reduction in water uptake, ingress rate and water molecular mobility with increasing value of n is explained by a combination of several physico-chemical molecular properties. The increased [CH₂]/[amide] ratio and the reduced amount of crystallinity do not completely clarify the observed trends in water uptake and water molecular mobility in the copolymer series. It is shown that the increased chain mobility of the PA46 segments in the copolymers allows an improved coupling of the amide groups in the amorphous phase, explaining the observed decrease in water uptake. The important role of the morphology of the amorphous phase for water uptake is further demonstrated by annealing results and NMR relaxation experiments as a function of temperature.     

Alginate coating as carrier of oligofructose and inulin and to maintain the quality of fresh-cut apples

The aim of this study was to apply an edible coating containing prebiotics such as oligofructose and inulin to fresh-cut apple wedges. An assessment of the quality, sensory, polyphenol, and volatile attributes of coated and uncoated fresh-cut apple wedges was also undertaken. Fructan analysis showed that all prebiotics remained stable over the 14-d storage period and an intake of 100 g of apple supplies 1 to 3 g of prebiotics. Browning index, firmness, acidity remained stable throughout the 14 d compared to the control while applying prebiotic coatings resulted in an increase in soluble solids. Sensory and visual assessment indicated acceptable quality of apple wedges coated with prebiotics. HPLC analysis showed that levels of polyphenolic compounds were more stable in coated apple wedges (without prebiotic inclusions) than in uncoated control apples. No difference was found between O(2) and CO(2) headspace concentration of coated and uncoated samples. Significant differences (P < 0.001) were found for headspace volatile production between the samples. Most coated samples showed lower volatile production in the headspace than uncoated samples.     

Undular Hydraulic Jumps in Circular Conduits

Undular hydraulic jumps in circular conduits are considered with an experimental approach. Based on previous findings in rectangular channels, this research indicates differences in terms of shape effects. All present results depend on the filling ratio of the upstream conduit flow in addition to the upstream Froude number. The results include information on the wave crests and troughs, wave lengths, and generalized axial surface profiles. The wall surface profile is shown to be similar to the axial wave profile, but with smaller wave extrema and a wave shift. The design of conduits containing undular jumps should be avoided because of unstable flow. It is also demonstrated that conduits may choke in the presence of undular jumps, with a previously established choking number relating to a design limit. For flows with choking numbers in excess of 1, choking occurs associated with a transition from the free surface to the pressurized conduit flow.     

Daily dietary molybdenum intake in Belgium using duplicate portion sampling

 For the first time daily dietary molybdenum intake in Belgium has been evaluated by duplicate portion sampling, heating in a microwave oven for destruction and atomic absorption spectrometric determination of this element. The mean intake value (87±11 μg/day) is lower than levels found for most other countries and is situated at the lower end of the recommended range for a safe and adequate daily dietary intake. Received: 14 October 1996