Cognitive deficits in docosahexaenoic acid-deficient rats.

This study investigated the influence of brain docosahexaenoic acid (DHA) deficiency on simple and complex olfactory-based learning and memory in 2nd generation (F2) adult male rats. Rats raised and maintained on either an n-3-adequate or an n-3-deficient diet were tested for acquisition of an olfactory learning set and an olfactory memory task, and for motivation to obtain a water reward. Despite a 76% decrease in brain DHA, n-3-deficient rats were able to acquire most simple 2-odor discrimination tasks but were deficient in the acquisition of a 20-problem olfactory learning set. This deficit could not be attributed to changes in sensory capacity but, instead, appeared to represent a deficit in higher order learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental solid–liquid equilibria and solid formation kinetics for carbon dioxide in methane for LNG processing

In cryogenic liquefaction processes, CO₂ poses a solid-formation risk even in trace concentrations. We present solid–fluid equilibrium (SFE) data for CO₂ in liquid methane at CO₂ concentrations from (52 to 500) ppm, extending the available data and indicating that models tuned to existing data over predict the solubility of CO₂ at LNG storage temperatures (~112 K) by nearly a factor of 3. The new data are used to improve the SFE model in the ThermoFAST software package. The formation kinetics of CO₂ solids in liquid methane are elucidated at conditions relevant to cryogenic gas processing. Repeated, ramped-temperature formation measurements provide a statistical basis for quantifying solidification risk. Nucleation rates extracted from the ramped-temperature data, consistent with those measured at fixed temperature, were used to extract parameters describing CO₂ solid formation in methane. These results significantly improve the ability to predict CO₂ solid formation risk in cryogenic natural gas processing.     

The relations of daily task accomplishment satisfaction with changes in affect: A multilevel study in nurses.

Focusing on a sample of nurses, this investigation examined the relationships of daily task accomplishment satisfaction (for direct and indirect care tasks) with changes in positive and negative affect from preshift to postshift. Not accomplishing tasks to one's satisfaction was conceptualized as a daily workplace stressor that should increase daily negative affect and decrease daily positive affect from preshift to postshift. Further, because of the greater centrality of direct care nursing tasks to nursing work role identities (relative to indirect care tasks), we expected that task accomplishment satisfaction (or lack thereof) for these tasks would have stronger effects on changes in affect than would task accomplishment satisfaction for indirect care tasks. We also examined 2 person-level resources, collegial nurse–physician relations and psychological resilience, as moderators of the relationships among these daily variables, with the expectation that these resources would buffer the harmful effects of low task accomplishment satisfaction on nurse affect. Results supported almost all of the proposed effects, though the cross-level interactions were observed only for the effects of indirect care task accomplishment satisfaction on affect and not for direct care task accomplishment satisfaction on affect. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Time course of processing emotional stimuli as a function of perceived emotional intelligence, anxiety, and depression.

An individual's self-reported abilities to attend to, understand, and reinterpret emotional situations or events have been associated with anxiety and depression, but it is unclear how these abilities affect the processing of emotional stimuli, especially in individuals with these symptoms. The present study recorded event-related brain potentials while individuals reporting features of anxiety and depression completed an emotion-word Stroop task. Results indicated that anxious apprehension, anxious arousal, and depression were associated with self-reported emotion abilities, consistent with prior literature. In addition, lower anxious apprehension and greater reported emotional clarity were related to slower processing of negative stimuli indexed by event-related potentials (ERPs). Higher anxious arousal and reported attention to emotion were associated with ERP evidence of early attention to all stimuli regardless of emotional content. Reduced later engagement with stimuli was also associated with anxious arousal and with clarity of emotions. Depression was not differentially associated with any emotion processing stage indexed by ERPs. Research in this area may lead to the development of therapies that focus on minimization of anxiety to foster successful emotion regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Numerical study of hydrogen triple flame response to mixture stratification,ambient temperature,pressure, and water vapor concentration

Mixing layer simulations of spark-ignited H₂/air that detail the influence of mixing layer thickness, domain pressure and air temperature, and water vapor concentration have been carried out. The stabilization speed of the propagating flame front is shown to increase with increasing mixing layer thickness as a result of streamline divergence ahead of the triple flame structure. The pressure changes considered are small (1, 2 bar), and within this range the pressure has only a modest effect on propagation speeds, while air layer temperature effects (298 K, 750 K) are pronounced. Higher adiabatic flame temperatures produced by elevated air temperature have been shown to lead to increased formation of nitrogen oxides. This tendency can be counteracted by increasing inert concentration. Therefore, the influence of water vapor concentration on emissions has been considered in studies where air layer species concentrations are replaced with up to 50% water by mole. Resulting changes in flame structure, heat release rates, flame speed, and emission concentrations – estimated through use of the standard Zeldovich NO mechanism, are given. Data trends for all parameter effects have been related to expected qualitative predictions for direct-injection hydrogen internal combustion engine behavior.     

Mg2FeH6–LiBH4 and Mg2FeH6–LiNH2 composite materials for hydrogen storage

Two composite hydrogen storage materials based on Mg₂FeH₆ were investigated for the first time. The Mg₂FeH₆–LiBH₄ composite of molar ratio 1:5 showed a hydrogen desorption capacity of 5.6 wt.% at 370 °C, and could be rehydrogenated to 3.6 wt.% with the formation of MgH₂, as the material was heated to 445 °C and held at this temperature. The Mg₂FeH₆–LiNH₂ composite of 3:10 molar ratio exhibited a hydrogen desorption capacity of 4.3 wt.% and released hydrogen at 100 °C lower then the Mg₂FeH₆–LiBH₄ composite, but this mixture could not be rehydrogenated. Compared to neat Mg₂FeH₆, both composites show enhanced hydrogen storage properties in terms of desorption kinetics and capacity at these low temperatures. In particular, Mg₂FeH₆–LiNH₂ exhibits a much lower desorption temperature than neat Mg₂FeH₆, but only Mg₂FeH₆–LiBH₄ re-absorbs hydrogen.     

Quantitative Standards of 4-O-Acetyl- and 9-O-Acetyl-N-Acetylneuraminic Acid for the Analysis of Plasma and Serum

N-Acetylneuraminic acid (sialic acid, Neu5Ac) is one of a large, diverse family of nine-carbon monosaccharides that play roles in many biological functions such as immune response. Neu5Ac has previously been identified as a potential biomarker for the presence and pathogenesis of cardiovascular disease (CVD), diabetes and cancer. More recent research has highlighted acetylated sialic acid derivatives, specifically Neu5,9Ac₂, as biomarkers for oral and breast cancers, but advances in analysis have been hampered due to a lack of commercially available quantitative standards. We report here the synthesis of 9-O- and 4-O-acetylated sialic acids (Neu5,9Ac₂ and Neu4,5Ac₂) with optimisation of previously reported synthetic routes. Neu5,9Ac₂ was synthesised in 1 step in 68 % yield. Neu4,5Ac₂ was synthesised in 4 steps in 39 % overall yield. Synthesis was followed by analysis of these standards via quantitative NMR (qNMR) spectroscopy. Their utilisation for the identification and quantification of specific acetylated sialic acid derivatives in biological samples is also demonstrated.     

GC-IMS and machine learning for the rapid differentiation of complex isomeric mixtures of terpenes

Zinc is an essential trace element (TE). Insufficient supply can lead to severe health effects. According to current estimations, about 20% of the world's population are at risk of an insufficient zinc supply. Thereby geographic differences occur. In developing countries and emerging countries the population is at substantially higher risk of zinc deficiency, compared to industrial countries. In the latter, mostly people from specific population groups are at risk. Among them are elderly people, as studies have shown a decrease in the total zinc concentration of the serum with increasing age. To treat zinc deficiency, it hast to be diagnosed first. Biomarkers established so far are well suited to evaluate the zinc status of populations. However, they have their limitations when it comes to individuals. A good biomarker for this application area is still missing. In this context, the serum free zinc concentration has been suggested as a possible biomarker for the zinc status of individuals. The term free zinc describes the zinc pool that is loosely bound to low molecular weight fractions. Data in the literature implictates that free zinc represents the zinc that is biologically active and available for interaction with cells. Hence, the serum free zinc concentration might be a better parameter to reflect an individual's zinc status than the total zinc concentration. Therefore, in the present work a fluorescent-probe based assay was established for determining the free zinc concentration in human and murine serum samples. The determined free zinc concentrations of the analyzed serum samples were in the nanomolar range. The free and total zinc concentrations in the sera of the different sample-groups analyzed either showed no linear correlation or a weak linear correlation. In several sample-groups analyzed, the free zinc concentration in sera from females was significantly lower than in sera from males. The data obtained support the meaning of the serum free zinc concentration as an independent parameter besides the total zinc concentration. However, based on the current data it cannot be evaluated yet, if the free zinc concentration in serum is a well-suited biomarker for an individual's zinc status. Still it seems promising to further investigate this parameter, with regard to its suitability as a biomarker as well as its physiological relevance. In the context of the present work, samples from a feeding study with mice were analyzed. The aim of the study was to investigate the influence of TE-supply on age-related alterations in TE-homeostasis and TE-dependent physiological processes. Adult and old mice were treated with a TE-supply either adequate, suboptimal in several TEs (zinc, selenium, copper, iron) simultaneously or age-adjusted. The latter had an elevated content of zinc and selenium and aimed to investigate, whether age-related alterations can be prevented by an elevated supply of TEs, whose serum concentration decreases with increasing age. As a central organ of the body's zinc-homeostasis, the liver was examined. For this, a fluorescent-probe based assay was established for determining the free zinc concentration in homogenized murine liver tissue. A tendency of the free zinc concentration in the liver tissue to reflect the zinc-supply of the mice was shown. In addition, the free zinc concentration in liver tissue samples from female mice was significantly higher than in samples from male mice. The total zinc content of the liver tissue showed no such effects of zinc supply or sex. The age of the mice did not affect the free zinc concentration of the liver tissue. The functionality of the immune system is dependent on zinc, in addition shows age-related alteration. Therefore, as part of the immune system, isolated splenocytes were examined. The percentage of B-cells, T-helper cells, cytotoxic T-cells, macrophages and dendritic cells was determined, as well as the respective cellular free zinc concentration and the relative content of several pro- and anti-inflammatory cytokines (interleukin (IL)-2, IL-10, IL-17, interferon-γ and tumor necrosis factor α) in the supernatant after stimulation with phytohaemagglutinin (PHA). A decrease in the percentage of T-helper cells, an increase in percentage of dendritic cells, a decrease in the cellular free zinc concentration of B-cells and dendritic cells as well as an increase in relative IL-10 content in the supernatant after stimulation with PHA was shown in relation to age. The age-adjusted TE-supply showed no effect on these age-related alterations of the immune system. This implicates that the underlying mechanisms are not modulated by an enhanced nutritional supply of zinc and selenium.     

RectEuler: Visualizing Intersecting Sets using Rectangles

Euler diagrams are a popular technique to visualize set-typed data. However, creating diagrams using simple shapes remains a challenging problem for many complex, real-life datasets. To solve this, we propose RectEuler: a flexible, fully-automatic method using rectangles to create Euler-like diagrams. We use an efficient mixed-integer optimization scheme to place set labels and element representatives (e.g., text or images) in conjunction with rectangles describing the sets. By defining appropriate constraints, we adhere to well-formedness properties and aesthetic considerations. If a dataset cannot be created within a reasonable time or at all, we iteratively split the diagram into multiple components until a drawable solution is found. Redundant encoding of the set membership using dots and set lines improves the readability of the diagram. Our web tool lets users see how the layout changes throughout the optimization process and provides interactive explanations. For evaluation, we perform quantitative and qualitative analysis across different datasets and compare our method to state-of-the-art Euler diagram generation methods.