Origins of Catalyst Inhibition in the Manganese Catalysed Oxidation of Lignin Model Compounds with H2O2.
ChemSusChem. 2019 Apr 19;:
Authors: Barbieri A, Kasper JB, Mecozzi F, Lanzalunga O, Browne WR
The upgrading of complex bio-renewable feedstock, such as lignocellulose, through depolymerisation benefits from the selective reactions at key functional groups. Applying homogeneous catalysts developed for selective organic oxidative transformations to complex feedstock such as lignin is challenged by the presence of interfering components. The selection of appropriate model compounds is essential in applying new catalytic systems and identifying such interferences. We show here using the oxidation of a model substrate containing a β-O-4 linkage with H2O2 and an in situ prepared manganese based catalyst, capable of efficient oxidation of benzylic alcohols, that interference from compounds liberated during the reaction can prevent its application to lignocellulose depolymerisation.
PMID: 31001914 [PubMed – as supplied by publisher]
Posted in ChemSusChem
Micro- and macroparasite species richness in birds: the role of host life history and ecology.
J Anim Ecol. 2019 Apr 19;:
Authors: Gutiérrez JS, Piersma T, Thieltges DW
1.Identifying the factors shaping variation in parasite diversity among host species is crucial to understand wildlife diseases. Although micro- and macroparasites may exert different selective pressures on their hosts, studies investigating the determinants of parasite species richness in animals have rarely considered this divide. 2.Here, we investigated the role of host life history and ecology in explaining the species richness of helminths (macroparasites) and haemosporidians (microparasites) in birds worldwide. We collated data from multiple global datasets on diverse bird traits (longevity, body mass, coloniality, migration distance/tendency, geographic range size and dietary and habitat breadths) and the species richness of their helminth and haemosporidian parasites. We tested predictors of helminth and haemosporidian parasite richness using phylogenetic generalised linear mixed models in a Bayesian framework. 3.We found that, after controlling for research effort and host phylogeny, the richness of helminths, but not of haemosporidians, increased with host longevity, range size, migration distance and dietary breadth. Overall, these correlates were also important across different helminth groups (acanthocephalans, cestodes, nematodes and trematodes), and two additional ones (body mass, coloniality) emerged as important for cestodes and acanthocephalans. 4.We propose that long lifespans may promote the diversity of helminth parasite assemblages over evolutionary time, thus resulting in richer helminth faunas. Similarly, longer-distance migrations, larger ranges and broader dietary breadths are likely to lead to greater encounter rates and the accumulation of trophically-transmitted helminths. In contrast, vector-borne haemosporidians may be influenced more by factors related to vector ecology than by the host traits included in the analyses. The lack of strong associations between haemosporidian species richness and host characteristics emphasizes the need to find appropriate traits to model the distribution and diversity of parasites with different environmental preferences in order to anticipate disease emergence risks associated with global change. This article is protected by copyright. All rights reserved.
PMID: 31002193 [PubMed – as supplied by publisher]
Posted in J Anim Ecol
The Upper Hand of the Otu Amyloid Fibers: Increasing Enzymatic Activity and Prolonging Lifespan.
Mol Cell. 2019 Apr 18;74(2):225-226
Authors: Rabouille C
The formation of amyloid fibers is usually associated with aging and neurodegeneration. In this issue of Molecular Cell, Ji et al. (2019) demonstrate that the deubiquitinase Otu coalesces into amyloid-like fibers to enhance its activity and ensure its optimum biological function.
PMID: 31002803 [PubMed – in process]
Posted in Mol Cell
Temporal integration and attentional selection of color and contrast target pairs in rapid serial visual presentation.
Acta Psychol (Amst). 2019 Apr 16;196:56-69
Authors: Karabay A, Akyürek EG
Performance in a dual target rapid serial visual presentation task was investigated, dependent on whether the color or the contrast of the targets was the same or different. Both identification accuracy on the second target, as a measure of temporal attention, and the frequency of temporal integration were measured. When targets had a different color (red or blue), overall identification accuracy of the second target and identification accuracy of the second target at Lag 1 were both higher than when targets had the same color. At the same time, increased temporal integration of the targets at Lag 1 was observed in the different color condition, even though actual (non-integrated) single targets never consisted of multiple colors. When the color pairs were made more similar, so that they all fell within the range of a single nominal hue (blue), these effects were not observed. Different findings were obtained when contrast was manipulated. Identification accuracy of the second target was higher in the same contrast condition than in the different contrast condition. Higher identification accuracy of both targets was furthermore observed when they were presented with high contrast, while target contrast did not influence temporal integration at all. Temporal attention and integration were thus influenced differently by target contrast pairing than by (categorical) color pairing. Categorically different color pairs, or more generally, categorical feature pairs, may thus afford a reduction in temporal competition between successive targets that eventually enhances attention and integration.
PMID: 31002976 [PubMed – as supplied by publisher]
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