Chylomicron and VLDL TAG structures and postprandial lipid response induced by lard and modified lard

Alterations in chylomicron and VLDL TAG and the magnitude of postprandial lipemia were studied in healthy volunteers after two meals of equal FA composition but different TAG-FA positional distribution. Molecular level information of individual lipoprotein TAG regioisomers was obtained with a tandem MS method. The incremental area under the response curve of VLDL TAG was large (P=0.021) after modified lard than after lard. In plasma TAG, the difference did not quite reach statistical significance (P=0.086). In general, there were less TAG with palmitic acid in the sn-2 position and more TAG with oleic acid in the sn-2 position in chylomicrons than in fat ingested. From 1.5 to 8 h postprandially, the proportion of individual chylomicron TAG was constant or influenced by TAG M.W. VLDL TAG regioisomerism was similar regardless of the positional distribution of fat ingested. Significant alterations were seen in VLDL TAG FA, in M.W. fractions, and in individual regioisomers with respect to time. The TAG sn-14∶0-18∶1-18∶1+sn-18∶1-18∶1-14∶0, sn-16∶0-16∶1-18∶1+sn-18∶1-16∶1-16∶0, and sn-16∶1-18∶1-18∶1+sn-18∶1-18∶1-16∶1 decreased (P<0.05); and sn-16∶0-16∶0-18∶2+sn-18∶2-16∶0-16∶0, sn-16∶0-16∶0-18∶1+sn-18∶1-16∶0-16∶0, sn-16∶0-18∶1-16∶0, and sn-16∶0-18∶1-18∶2+sn-18∶2-18∶1-16∶0 increased (P<0.05) after both meals. In conclusion, positional distribution of TAG FA was found to affect postprandial lipid metabolism in healthy normolipidemic subjects.     

Competition in denitrification systems affecting reduction rate and accumulation of nitrite

During the process of denitrification of wastewater nitrite has often been observed to accumulate, most probably because of the nitrite reduction rate falling behind the rate of nitrate reduction. The hypothesis to be investigated in this study was that microbial communities could be enriched for facultative anaerobes capable of reducing nitrate, but only to nitrite. A mathematical model was developed, and experiments were conducted to study results of enhanced proliferation of facultative anaerobes, on the expense of true denitrifiers, in activated sludge biocommunities. A lab-scale sequencing batch reactor system was employed for the studies. As predicted, the rate of nitrite reduction progressively decreased whereas the nitrate reduction rate remained almost unaffected, when fermentation conditions were introduced into the process schematic. Implications in design and operation of wastewater treatment plants are discussed.     

Placental Endocrine Activity: Adaptation and Disruption of Maternal Glucose Metabolism in Pregnancy and the Influence of Fetal Sex

The placenta is an endocrine fetal organ, which secretes a plethora of steroid- and proteo-hormones, metabolic proteins, growth factors, and cytokines in order to adapt maternal physiology to pregnancy. Central to the growth of the fetus is the supply with nutrients, foremost with glucose. Therefore, during pregnancy, maternal insulin resistance arises, which elevates maternal blood glucose levels, and consequently ensures an adequate glucose supply for the developing fetus. At the same time, maternal β-cell mass and function increase to compensate for the higher insulin demand. These adaptations are also regulated by the endocrine function of the placenta. Excessive insulin resistance or the inability to increase insulin production accordingly disrupts physiological modulation of pregnancy mediated glucose metabolism and may cause maternal gestational diabetes (GDM). A growing body of evidence suggests that this adaptation of maternal glucose metabolism differs between pregnancies carrying a girl vs. pregnancies carrying a boy. Moreover, the risk of developing GDM differs depending on the sex of the fetus. Sex differences in placenta derived hormones and bioactive proteins, which adapt and modulate maternal glucose metabolism, are likely to contribute to this sexual dimorphism. This review provides an overview on the adaptation and maladaptation of maternal glucose metabolism by placenta-derived factors, and highlights sex differences in this regulatory network.     

Polyphosphazenes with Pyridylalkylamino Groups: Synthesis, Thermal Properties, Ion Uptake and -Selectivity

Summary Three series of polyphosphazenes with 25, 50, 75 and 100% of pendent 2-, 3-, or 4-pyridylmethylamino groups and in case of the co-polymers additional phenoxy groups were synthesized and characterized. The physical properties of the materials depend on the type of pyridine derivative, the amount of functional groups, and their arrangement (geminal or non-geminal) on the polymer chain. Characterization was performed by NMR, GPC and elemental analyses. Thermal studies show two degradation pathways: (1) depolymerization under formation of phosphazene rings for species with P(OPh)₂ and P(OPh)(NHCH₂C₅H₄N) units and (2) chain cleavage for polymers with high amounts of P(NHCH₂C₅H₄N)₂ groups. Ion uptake and -selectivity of the new materials were also investigated. 2-Pyridylalkylamino derivatives show increasing capacity and selectivity for copper in the presence of nickel or cobalt as the amount of functional groups increases whereas capacities and selectivities of the 3- and 4-pridylmethlyamino substituted polymers are surprisingly low and decrease even with increasing functionalization within the series of the 4-pyridylmethylamino polyphosphazenes. Dedicated to Harry R. Allcock, my host and friend at the Pennsylvania State University who taught me the fascination of polyphosphazene chemistry.     

Signaling in expository hypertexts compensates for deficits in reading skill.

[Correction Notice: An erratum for this article was reported in Vol 101(2) of Journal of Educational Psychology (see record 2009-04640-014). The URL published for the supplemental material was incorrect. The correct URL is provided in the erratum.] Expository hypertexts may contain specific types of signals such as navigable topical overviews and hyperlinks that map conceptual relationships between text contents. Two experiments with German university students (N = 130, 75% female, mean age 25 years) were conducted to test the hypothesis that hypertext-specific signals particularly support learners with badly routinized reading skills in organizing and integrating complex learning materials. The experiments were based on naturalistic texts and essay-writing tasks typical for exam preparation. Learning outcomes were measured by characteristics of participants' essays (amount of knowledge, knowledge focusing, knowledge integration). In both experiments, a hypertext with a high amount of signaling yielded better learning outcomes than did a linear text for readers with a low level of skill, whereas there were no differences for readers with a high level of skill (ΔR2 from .03 to .08 for the interaction). In Experiment 2, the same interaction pattern was found for hypertext with a high versus a low amount of hypertext-specific signals (ΔR2 from .04 to .10). Moreover, a lack of signals led to less efficient navigation behavior. These results demonstrate that hypertexts equipped with hypertext-specific signals may compensate for deficits in reading skill. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diffusion coefficient measurements in consolidated clay by RBS micro-scale profiling

The determination of radionuclide diffusion coefficients is necessary for performance assessment of clay formations as a geological barrier for deep geological repositories for high-level radioactive waste.Diffusion coefficients of elements that are retained by the clay and have short diffusion lengths are quite difficult to measure over reasonable time spans, by conventional techniques.This paper presents a novel application of the Rutherford Backscattering Spectrometry (RBS) technique to determine solute diffusion coefficients in consolidated clays. The RBS technique was selected because it allows the measurement of concentration profiles at short range distances (μm).The proposed methodology was tested on the Opalinus clay (OPA) from the Swiss Jura, where the Mont Terri underground laboratory is located. The diffusion of four elements with different adsorption behaviors onto the clay was analyzed: Eu and U as adsorbing elements, Sr as low adsorbing, and Re as a non-adsorbing element with anionic behavior.Apparent diffusion coefficients (D_a) could be experimentally determined for Re, Eu and U after a few days of diffusion time, while for Sr it was only possible to estimate a lower limit for the diffusion coefficient. The uncertainties of the proposed methodology are discussed on the basis of sensitivity studies.     

Transformations for within-subject designs: A Monte Carlo investigation.

Explored the use of transformations to improve power in within-S designs in which multiple observations are collected for each S in each condition, such as reaction time (RT) and psychophysiological experiments. Often, the multiple measures within a treatment are simply averaged to yield a single number, but other transformations have been proposed. Monte Carlo simulations were used to investigate the influence of those transformations on the probabilities of Type I and Type II errors. With normally distributed data, Z and range correction transformations led to substantial increases in power over simple averages. With highly skewed distributions, the optimal transformation depended on several variables, but Z and range correction performed well across conditions. Correction for outliers was useful in increasing power, and trimming was more effective than eliminating all points beyond a criterion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Support film in transmission electron microscopy: experiences with polyvinyl butyral Pioloform BM 18

Microscopic work with single-slot grids requires high-quality support films to span the relatively large gap. The imminent unavailability of the polyvinyl formal Pioloform FN 65, which to date has been used as the standard polyvinyl formal for the generation of support films in transmission electron microscopy (TEM), has necessitated the finding of a substitute material to produce such films. Therefore, we compared the polyvinyl butyral Pioloform BM 18 with the polyvinyl formal Pioloform FN 65 for the production of TEM support films, using operational criteria for assessment. Pioloform BM 18 with the solvent chloroform resulted in support films of unacceptable quality compared with Pioloform FN 65. Adding the softener dibutyl phthalate to the chloroform solvent for Pioloform BM 18 markedly improved the film quality, resulting in support films with high transparency and flexibility, and even greater stability in the electron beam when compared with films of Pioloform FN 65. Pioloform FN 65 also had the disadvantage of requiring highly toxic 1,2-dichloroethane as a solvent, whereas Pioloform BM 18 can be used with chloroform.     

ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells <Emphasis Type="Italic">in vitro</Emphasis>

Asbestos is a known carcinogen and co-carcinogen. It is a persisting risk in our daily life due to its use in building material as asbestos-cement powder. The present study done on V79-cells (Chinese hamster lung cells) demonstrates the cytotoxic and genotoxic potential of asbestos-cement powder (ACP) in comparison with chrysotile asbestos. A co-exposure of chrysotile and ACP was tested using the cell viability test and the micronucleus assay. The kinetochore analysis had been used to analyse the pathway causing such genotoxic effects. Thiobarbituric acid-reactive substances were determined as evidence for the production of reactive oxygen species. Both, asbestos cement as well as chrysotile formed micronuclei and induced loss of cell viability in a concentration- and time- dependent way. Results of TBARS analysis and iron chelator experiments showed induction of free radicals in ACP- and chrysotile exposed cultures. CaSO₄ appeared to be a negligible entity in enhancing the toxic potential of ACP. The co-exposure of both, ACP and chrysotile, showed an additive effect in enhancing the toxicity. The overall study suggests that asbestos-cement is cytotoxic as well as genotoxic in vitro. In comparison to chrysotile the magnitude of the toxicity was less, but co-exposure increased the toxicity of both.