The internal surface area of Na-Wyoming bentonite was determined for linearly swelling pastes, using a physically based equation which describes such swelling. Information required is simply the linear relationship between interplatelet spacing, determined by X-ray powder diffraction, vs total water content determined gravimetrically. However, before the three-unknown parameter equation can be so applied, that portion of external-pore water, which normally increases linearly commensurately as interstitial water increases, must be decreased to zero. This was accomplished by adding dilute quantities of NaCl salt to the clay-paste system to decrease the attractive forces between positive-edge and negative-face sites, and stirring vigorously to further destroy the card-house structure and align the clay platelets.

Tight focusing with very small f-numbers is necessary to achieve the highest at-focus irradiances. However, tight focusing imposes strong demands on precise target positioning in-focus to achieve the highest on-target irradiance. We describe several near-infrared, visible, ultraviolet and soft and hard X-ray diagnostics employed in a ∼1022 W/cm2 laser–plasma experiment. We used nearly 10 J total energy femtosecond laser pulses focused into an approximately 1.3-μm focal spot on 5–20 μm thick stainless-steel targets. We discuss the applicability of these diagnostics to determine the best in-focus target position with approximately 5 μm accuracy (i.e., around half of the short Rayleigh length) and show that several diagnostics (in particular, 3$\omega$ reflection and on-axis hard X-rays) can ensure this accuracy. We demonstrated target positioning within several micrometers from the focus, ensuring over 80% of the ideal peak laser intensity on-target. Our approach is relatively fast (it requires 10–20 laser shots) and does not rely on the coincidence of low-power and high-power focal planes.

Accumulating evidence suggests that deficits of visual selective attention may already occur at early stages of Alzheimer's disease (AD) like the prodromal phase of mild cognitive impairment (MCI).

Our study investigated visual selective attention in amnestic MCI and probable AD patients compared to healthy elderly controls. Groups were matched for age, gender and education. In combination with Bundesen's ‘theory of visual attention’, two mathematically independent and quantitative parameter estimates were derived from a partial report of briefly presented letter arrays: top-down control of attentional selection, representing task-related attentional weighting for prioritizing relevant visual objects, and spatial distribution of attentional weights across the left and right hemifield.

Compared to controls, MCI patients showed significantly reduced top-down controlled selection which further deteriorated in AD subjects. Moreover, attentional weighting was significantly unbalanced across hemifields in MCI and tended to be more lateralized in AD. The majority of patients was biased to the left. Across MCI and AD patients, carriers of the apolipoprotein E ɛ4 allele (ApoE4) revealed a leftward spatial bias. The leftward bias was the more pronounced the younger the ApoE4-positive patients and the earlier disease onset. ApoE4-negative subjects showed balanced attentional weighting.

These results indicate that impaired top-down control may be linked to early dysfunction of fronto-parietal cortico-cortical networks. Accompanying, an early interhemispheric asymmetry in temporo-parietal cortical interactions might cause a pathological spatial bias. As the inheritance of ApoE4 is associated with asymmetric parietal metabolism, a pathological spatial bias may function as early cognitive marker for detecting probable AD subjects.

Schizophrenia is often accompanied by cognitive dysfunctions. Post-mortem and in vivo studies have revealed increased cortical 5-HT1A-receptor density and it was assumed that 5-HT1A-receptor active drugs could enhance cognition. Moreover, partial 5-HT1A-receptor agonists positively affected verbal memory in schizophrenic patients. However, the role of the 5-HT1A-receptor for cognition has not been fully clarified.

Recently, we have introduced transgenic mice overexpressing the 5-HT1A-receptor postsynaptically in the cortex and hippocampus. Function of the surplus receptors was verified by receptor activation with the agonist 8-OH-DPAT.

In this study we further investigated the role of postsynaptic 5-HT1A-receptors for cognition. Therefore, our mice were tested in the inhibitory avoidance, Morris water maze, and hole-board habituation task. Moreover, the effects of low and high doses of 8-OH-DPAT were examined in the inhibitory avoidance task.

Our transgenic mice showed no overall cognitive deficit. As a tendency, inhibitory avoidance retention was impaired in transgenic mice compared to wild-type controls. Both genotypes showed similar spatial learning abilities in the Morris water maze and habituated to the hole-board in a comparable manner. Anterograde amnesia induced by 8-OH-DPAT was in transgenic mice already apparent in a third of the dose used for wild-type mice. Retrograde amnesia could not be triggered.

Since the transgenic mice show untreated a rather normal behaviour, we assume that they possess compensatory mechanisms. However, after activation of the postsynaptic 5-HT1A-receptors the differences between wild-type and transgenic mice became more clear. Hence, our findings suggest that the cortical and hippocampal 5-HT1A-receptors play rather a modulatory role in learning.

Ammoniation of montmorillonites pillared with polyhydroxo-complexes of Al was performed in flow conditions at 773–1073 K and monitored by IR spectroscopy. Interaction of the clay with ammonia revealed exchange of terminal and bridging -OH groups by NH2-, NH- and N- species depending on the reaction temperature. Amination begins at 773 K while formation of NH groups starts at 873 K. Transformation of NH- into N-species occurs at 973 K. A mechanism for the ammoniation reaction is proposed and the series of the relative reactivity of OH groups was established: Si–OH > Mg–OH–Mg > Al–OH–Mg > Al–OH–Al. This series was rationalized in terms of accessibility of the OH groups.

Rates of 0 and 5 lb/A of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) or 2-chloro-4,6-bis(ethylamino)–s-triazine (simazine) were combined with O and 200 lb/A of nitrogen fertilizer as preemergence applications on plots planted to corn (Zea mays L., var. Mo. 880) in May of 1964 and 1965. Soil samples collected in December, 1965, and again in February, 1966, were plated on Difco potato dextrose agar and nutrient agar to determine the growth of fungal and bacterial colonies. There was no difference in the total number of fungal colonies grown on media seeded with soils from the field studies, yet variation in individual species occurred. The number of bacterial colonies increased on plates seeded with soil from plots treated with 200 lb/A of nitrogen plus 5 lb/A of simazine but not from simazine-treated soil without nitrogen.

Disparity appears to decrease or remain stable over geological time in numerous groups. This pattern is sometimes explained in terms of developmental constraints, but labile developmental systems might produce the same pattern should novelties interact, counterbalancing their individual effects. We test the hypothesis that counterbalancing can reduce disparity by comparing ontogenies of shape among nine species of piranhas to identify the developmental novelties. All three parameters examined change multiple times, sometimes dramatically. By comparing levels of disparity between species at two developmental phases, at the transition from larval to juvenile phases, and at maximum adult body size, we find that disparity decreases significantly and substantially over ontogeny. That reduction occurs because of, rather than despite, novelties of postlarval morphogenesis. Some interacting novelties are historically independent and affect different developmental phases, others are historically independent and affect the same developmental phase, and still others are historically correlated and affect either the same or different developmental phases. By modeling hypothetical ontogenies, constraining developmental parameters mathematically to one of the observed values, we find that variation in each parameter, taken by itself, and combinations of them taken two at a time, tend to increase disparity. It is the interactions among all three that reduce disparity. In this group divergent ontogenies transform disparate larvae into similar adults.

Prebiotic oligosaccharides, including galacto-oligosaccharides (GOS), are used in infant formula to mimic human milk oligosaccharides, which are known to have an important role in the development of the intestinal microbiota and the immune system in neonates. The maturation of the intestines in piglets closely resembles that of human neonates and infants. Hence, a neonatal piglet model was used to study the multi-faceted effect of dietary GOS in early life. Naturally farrowed piglets were separated from the mother sow 24–48 h postpartum and received a milk replacer with or without the addition of GOS for 3 or 26 d, whereafter several indicators of intestinal colonisation and maturation were measured. Dietary GOS was readily fermented in the colon, leading to a decreased pH, an increase in butyric acid in caecum digesta and an increase in lactobacilli and bifidobacteria numbers at day 26. Histomorphological changes were observed in the intestines of piglets fed a GOS diet for 3 or 26 d. In turn, differences in the intestinal disaccharidase activity were observed between control and GOS-fed piglets. The mRNA expression of various tight junction proteins was up-regulated in the intestines of piglet fed a GOS diet and was not accompanied by an increase in protein expression. GOS also increased defensin porcine β-defensin-2 in the colon and secretory IgA levels in saliva. In conclusion, by applying a neonatal piglet model, it could be demonstrated that a GOS-supplemented milk replacer promotes the balance of the developing intestinal microbiota, improves the intestinal architecture and seems to stimulate the intestinal defence mechanism.