Mathematical predictions of oxygen availability in micro- and macro-encapsulated human and porcine pancreatic islets.
J Biomed Mater Res B Appl Biomater. 2019 Apr 23;:
Authors: Cao R, Avgoustiniatos E, Papas K, de Vos P, Lakey JRT
Optimal function of immunoisolated islets requires adequate supply of oxygen to metabolically active insulin producing beta-cells. Using mathematical modeling, we investigated the influence of the pO2 on islet insulin secretory capacity and evaluated conditions that could lead to the development of tissue anoxia, modeled for a 300 μm islet in a 500 μm microcapsule or a 500 μm planar, slab-shaped macrocapsule. The pO2 was used to assess the part of islets that contributed to insulin secretion. Assuming a 500 μm macrocapsule with a 300 μm islet, with oxygen consumption rate (OCR) of 100-300 nmol min-1 mg-1 DNA, islets did not develop any necrotic core. The nonfunctional zone (with no insulin secretion if pO2 < 0.1 mmHg) was 0.3% for human islets (OCR ~100 nmol/min/mg DNA) and 35% for porcine islets (OCR ~300 nmol/min/mg DNA). The OCR of the islet preparation is profoundly affected by islet size, with optimal size of <250 μm in diameter (human) or <150 μm (porcine). Our data suggest that microcapsules afford superior oxygen delivery to encapsulated islets than macrocapsules, and optimal islet function can be achieved by encapsulating multiple, small (<150 μm) islets with OCR of ~100 nmol min-1 mg-1 DNA (human islets) or ~200 nmol min-1 mg-1 DNA (porcine islets).
PMID: 31013399 [PubMed – as supplied by publisher]
Daniela Moye Holz: Access to innovative medicines in a middle-income country Kanker is wereldwijd een belangrijke doodsoorzaak. Lage- en …
Anne Hobbelt: Towards prevention of AF progression Vroeg behandelen van risicofactoren voor atriumfibrilleren kan het voortschrijden van …
Jarl Eduard Mooyaart: Linkages between family background, family formation and disadvantage in young adulthood In toenemende mate veronderstellen …
Kees Woldendorp: Musculoskeletal pain & dysfunction in musicians In Nederland zijn ruim twee miljoen mensen bezig met actief muziek maken. Duizenden …
Lucas Maciel Rabello: The influence of load on tendons and tendinopathy Pezen zijn belangrijke structuren omdat ze beweging mogelijk maken door het …
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]
Stefan Knapen: Rhythm and blues. Chronobiology in the pathophysiology and treatment of mood disorders. Stemmingsstoornissen komen veel voor en hebben …
Floor Holvast: Depression in older age. Challenges for general practitioners. Holvast had als doel van haar proefschrift aspecten van zorg, die de …
Anet Veringa: Clinical pharmacology and therapeutic drug monitoring of voriconazole Om de behandeling met voriconazol – een middel tegen …
Marika Leving: Understanding the motor learning process in handrim wheelchair propulsion Vaardig zijn in het aandrijven van een hoepelrolstoel is …
Marcus Ang Han Nian: Anterior segment optical coherence tomography angiography. Development and application of OCT angiography for corneal …
Lotte Ramerman: Off-label use of antipsychotic medication in people with intellectual disabilities; Adherence to guidelines, long-term …
In samenwerking met het UMCG organiseert het Ommelander Ziekenhuis Groningen een informatiebijeenkomst over borstreconstructie. De …
Like what you see: Generalization of social learning determines art appreciation.
Acta Psychol (Amst). 2019 Apr 06;196:18-25
Authors: Boddez Y, Descheemaeker M, Mertens G, Truyts A, Van de Cruys S
We examine whether a stimulus generalization framework can provide insight in how experience shapes evaluative responses to artworks. Participants received positive information about one artwork and negative information about another artwork. Afterwards, we tested their evaluative responses not only to these artworks but also to similar artworks, which allowed us to assess generalization. Results showed that the artwork that was paired with positive information and the artwork that was similar to it were evaluated more positively than the other artworks. These findings confirm that theories that aim to explain art appreciation could benefit from taking learning and its generalization into account.
PMID: 30965201 [PubMed – as supplied by publisher]
Samiksha Ghimire:Optimizing Levofloxacin Dose in the Treatment of Multidrug-Resistant Tuberculosis. An Integrated PK/PD Approach Tuberculose (TB) is …