24 research outputs found

    On the reproducibility of extrusion-based bioprinting: round robin study on standardization in the field

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    The outcome of three-dimensional (3D) bioprinting heavily depends, amongst others, on the interaction between the developed bioink, the printing process, and the printing equipment. However, if this interplay is ensured, bioprinting promises unmatched possibilities in the health care area. To pave the way for comparing newly developed biomaterials, clinical studies, and medical applications (i.e. printed organs, patient-specific tissues), there is a great need for standardization of manufacturing methods in order to enable technology transfers. Despite the importance of such standardization, there is currently a tremendous lack of empirical data that examines the reproducibility and robustness of production in more than one location at a time. In this work, we present data derived from a round robin test for extrusion-based 3D printing performance comprising 12 different academic laboratories throughout Germany and analyze the respective prints using automated image analysis (IA) in three independent academic groups. The fabrication of objects from polymer solutions was standardized as much as currently possible to allow studying the comparability of results from different laboratories. This study has led to the conclusion that current standardization conditions still leave room for the intervention of operators due to missing automation of the equipment. This affects significantly the reproducibility and comparability of bioprinting experiments in multiple laboratories. Nevertheless, automated IA proved to be a suitable methodology for quality assurance as three independently developed workflows achieved similar results. Moreover, the extracted data describing geometric features showed how the function of printers affects the quality of the printed object. A significant step toward standardization of the process was made as an infrastructure for distribution of material and methods, as well as for data transfer and storage was successfully established

    On the reproducibility of extrusion-based bioprinting: round robin study on standardization in the field

    Get PDF
    The outcome of three-dimensional (3D) bioprinting heavily depends, amongst others, on the interaction between the developed bioink, the printing process, and the printing equipment. However, if this interplay is ensured, bioprinting promises unmatched possibilities in the health care area. To pave the way for comparing newly developed biomaterials, clinical studies, and medical applications (i.e. printed organs, patient-specific tissues), there is a great need for standardization of manufacturing methods in order to enable technology transfers. Despite the importance of such standardization, there is currently a tremendous lack of empirical data that examines the reproducibility and robustness of production in more than one location at a time. In this work, we present data derived from a round robin test for extrusion-based 3D printing performance comprising 12 different academic laboratories throughout Germany and analyze the respective prints using automated image analysis (IA) in three independent academic groups. The fabrication of objects from polymer solutions was standardized as much as currently possible to allow studying the comparability of results from different laboratories. This study has led to the conclusion that current standardization conditions still leave room for the intervention of operators due to missing automation of the equipment. This affects significantly the reproducibility and comparability of bioprinting experiments in multiple laboratories. Nevertheless, automated IA proved to be a suitable methodology for quality assurance as three independently developed workflows achieved similar results. Moreover, the extracted data describing geometric features showed how the function of printers affects the quality of the printed object. A significant step toward standardization of the process was made as an infrastructure for distribution of material and methods, as well as for data transfer and storage was successfully established

    Human Folate Bioavailability

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    The vitamin folate is recognized as beneficial health-wise in the prevention of neural tube defects, anemia, cardiovascular diseases, poor cognitive performance, and some forms of cancer. However, suboptimal dietary folate intake has been reported in a number of countries. Several national health authorities have therefore introduced mandatory food fortification with synthetic folic acid, which is considered a convenient fortificant, being cost-efficient in production, more stable than natural food folate, and superior in terms of bioavailability and bioefficacy. Other countries have decided against fortification due to the ambiguous role of synthetic folic acid regarding promotion of subclinical cancers and other adverse health effects. This paper reviews recent studies on folate bioavailability after intervention with folate from food. Our conclusions were that limited folate bioavailability data are available for vegetables, fruits, cereal products, and fortified foods, and that it is difficult to evaluate the bioavailability of food folate or whether intervention with food folate improves folate status. We recommend revising the classical approach of using folic acid as a reference dose for estimating the plasma kinetics and relative bioavailability of food folate

    On the timing of moulting processes in reproductively active Northern krill Meganyctiphanes norvegica

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    The interactions between moult phasing, growth and environmental cues in Northern krill (Meganyctiphanes norvegica) were examined through analysing populations at seasonal, weekly, and daily timescales. The analyses were carried out on resident populations of krill found in three different neritic locations that experience similar environmental signals (the Clyde Sea, Scotland; the Kattegat, Denmark; Gullmarsfjord, Sweden). Seasonal analyses were carried out on the Clyde Sea population and showed that moulting frequency increased significantly moving from winter to summer. The proportion of moulting females in summer samples was often more than double the proportion of moulting males, suggesting that females had a comparatively shorter intermoult period (IMP). Weekly samples taken from the Kattegat showed a similar pattern. However, although the difference between the proportion of female and male moulters was significant in one week, it was not another, mainly because of the variability in the proportion of female moulters. Such variability in females was equally evident in the daily samples taken at Gullmarsfjord. It suggests that females have a shorter IMP (12.5 days) than males (18.4 days) and are more likely to moult in synchrony. Nevertheless, the daily samples revealed that males are also capable of moult synchronisation, although less frequently than females. Shortened IMPs in females were not a result of the abbreviation of specific moult stages. Accordingly, reproductive activity did not alter the course of the normal moult cycle. There was no significant difference between the total body lengths of males and females indicating that females achieve the same levels of growth despite moulting more frequently and having to provision the energy-rich ovaries. This is in contrast to most other crustaceans where the energy costs of reproduction reduce female growth. The fact that females were less abundant than males, probably by suffering a greater level of mortality, suggests that different behavioural strategies, particularly vertical migration regimes, were adopted by each sex to maximise growth and reproduction
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