32 research outputs found

    Barriers and Facilitators to the Implementation of the Early-Onset Sepsis Calculator:A Multicenter Survey Study

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    Prior studies demonstrated the neonatal early-onset sepsis (EOS) calculator’s potential in drastically reducing antibiotic prescriptions, and its international adoption is increasing rapidly. To optimize the EOS calculator’s impact, successful implementation is crucial. This study aimed to identify key barriers and facilitators to inform an implementation strategy. A multicenter cross-sectional survey was carried out among physicians, residents, nurses and clinical obstetricians of thirteen Dutch hospitals. Survey development was prepared through a literature search and stakeholder interviews. Data collection and analysis were based on the Consolidated Framework for Implementation Research (CFIR). A total of 465 stakeholders completed the survey. The main barriers concerned the expectance of the department’s capacity problems and the issues with maternal information transfer between departments. Facilitators concerned multiple relative advantages of the EOS calculator, including stakeholder education, EOS calculator integration in the electronic health record and existing positive expectations about the safety and effectivity of the calculator. Based on these findings, tailored implementation interventions can be developed, such as identifying early adopters and champions, conducting educational meetings tailored to the target group, creating ready-to-use educational materials, integrating the EOS calculator into electronic health records, creating a culture of collective responsibility among departments and collecting data to evaluate implementation success and innovation results.</p

    Evaluation of diurnal responses of Tetradesmus obliquus under nitrogen limitation

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    Tetradesmus obliquus is an oleaginous microalga with high potential for triacylglycerol production. We characterized the biochemical composition and the transcriptional landscape of T. obliquus wild-type and the starchless mutant (slm1), adapted to 16:8 h light dark (LD) cycles under nitrogen limitation. In comparison to the nitrogen replete conditions, the diurnal RNA samples from both strains also displayed a cyclic pattern, but with much less variation which could be related to a reduced transcription activity in at least the usually highly active processes. During nitrogen limitation, the wild-type continued to use starch as the preferred storage compound to store energy and carbon. Starch was accumulated to an average content of 0.25 g·gDW−1, which is higher than the maximum observed under nitrogen replete conditions. Small oscillations were observed, indicating that starch was being used as a diurnal energy storage compound, but to a lesser extent than under nitrogen replete conditions. For the slm1 mutant, TAG content was higher than for the wild-type (average steady state value was 0.26 g·gDW−1 for slm1 compared to 0.06 g·gDW−1 for the wild-type). Despite the higher TAG content in the slm1, the conversion efficiency of photons into biomass components for the slm1 was only half of the one obtained for the wild-type. This is related to the observed decrease in biomass productivity (from 1.29 gDW·L−1·day−1 for the wild-type to 0.52 gDW·L−1·day−1 for the slm1). While the transcriptome of slm1 displayed clear signs of energy generation by degrading TAG and amino-acids during the dark period, no significant variation of these metabolites could be measured. When looking through the diurnal cycle, the photosynthetic efficiency was lower for the slm1 mutant compared to the wild-type especially during the second half of the light period, where starch accumulation occurred in the wild-type.publishedVersionPaid Open Acces

    The transcriptional response of bioreactor-grown Aspergillus niger cultures towards three oils

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    The industrially important fungus Aspergillus niger feeds naturally on decomposing plant material, for which it is equipped with a range of enzyme systems. A significant proportion of plant material are lipids that might be available either as for energy storage or as membrane building blocks. With 63 potential lipase-encoding genes in its genome, A. niger has the tools to degrade these extracellular lipids. In contrast to polysaccharide-degrading enzyme networks not much is known about the signalling and regulatory processes that control lipase expression and activity in fungi both under laboratory and natural occurring conditions

    Quantification of Tetradesmus obliquus (Chlorophyceae) cell size and lipid content heterogeneity at single-cell level

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    Much of our current knowledge of microbial growth is obtained from studies at a population level. Driven by the realization that processes that operate within a population might influence a population's behavior, we sought to better understand Tetradesmus obliquus (formerly Scenedesmus obliquus) physiology at the cellular level. In this work, an accurate pretreatment method to quantitatively obtain single cells of T. obliquus, a coenobia-forming alga, is described. These single cells were examined by flow cytometry for triacylglycerol (TAG), chlorophyll, and protein content, and their cell sizes were recorded by coulter counter. We quantified heterogeneity of size and TAG content at single-cell level for a population of T. obliquus during a controlled standard batch cultivation. Unexpectedly, variability of TAG content per cell within the population increased throughout the batch run, up to 400 times in the final stage of the batch run, with values ranging from 0.25 to 99 pg · cell−1. Two subpopulations, classified as having low or high TAG content per cell, were identified. Cell size also increased during batch growth with average values from 36 to 70 μm3 · cell−1; yet cell size variability increased only up to 16 times. Cell size and cellular TAG content were not correlated at the single-cell level. Our data show clearly that TAG production is affected by cell-to-cell variation, which suggests that its control and better understanding of the underlying processes may improve the productivity of T. obliquus for industrial processes such as biodiesel production

    Determination of variability of fermentor-grown Aspergillus niger

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    Knowledge of the biological and technical variation for fermentor-grown Aspergillus niger cultures is needed to design DNA microarray experiments properly. We cultured A. niger in batch-operated fermentor vessels and induced with D-xylose. Transcript profiles were followed in detail by qPCR for 8 genes. A variance components analysis was performed on these data to determine the origin and magnitude of variation within each process step for this experiment

    Determination of variability of fermentor-grown Aspergillus niger

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    Knowledge of the biological and technical variation for fermentor-grown Aspergillus niger cultures is needed to design DNA microarray experiments properly. We cultured A. niger in batch-operated fermentor vessels and induced with D-xylose. Transcript profiles were followed in detail by qPCR for 8 genes. A variance components analysis was performed on these data to determine the origin and magnitude of variation within each process step for this experiment

    Analysis of Variance Components Reveals the Contribution of Sample Processing to Transcript Variation▿ †

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    The proper design of DNA microarray experiments requires knowledge of biological and technical variation of the studied biological model. For the filamentous fungus Aspergillus niger, a fast, quantitative real-time PCR (qPCR)-based hierarchical experimental design was used to determine this variation. Analysis of variance components determined the contribution of each processing step to total variation: 68% is due to differences in day-to-day handling and processing, while the fermentor vessel, cDNA synthesis, and qPCR measurement each contributed equally to the remainder of variation. The global transcriptional response to d-xylose was analyzed using Affymetrix microarrays. Twenty-four statistically differentially expressed genes were identified. These encode enzymes required to degrade and metabolize d-xylose-containing polysaccharides, as well as complementary enzymes required to metabolize complex polymers likely present in the vicinity of d-xylose-containing substrates. These results confirm previous findings that the d-xylose signal is interpreted by the fungus as the availability of a multitude of complex polysaccharides. Measurement of a limited number of transcripts in a defined experimental setup followed by analysis of variance components is a fast and reliable method to determine biological and technical variation present in qPCR and microarray studies. This approach provides important parameters for the experimental design of batch-grown filamentous cultures and facilitates the evaluation and interpretation of microarray data

    The impact of day length on cell division and efficiency of light use in a starchless mutant of Tetradesmus obliquus

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    Large scale microalgal production will be primarily done under natural sunlight conditions, where microalgae will be exposed to diurnal cycles of light and dark (LD) and to differences in the length of both periods (photoperiod). Tetradesmus obliquus (formerly known as Scenedesmus obliquus), a strain with potential for biofuel production, and the starchless mutant slm1 were grown under 3 different LD periods: 16:8 h, 14:10 h and 12:12 h. Cell division started a fix number of hours after the light went on (sunrise), independently of the length of the photoperiod. For the wild-type, cell division started approximately 14 h after the beginning of the day and occurred mainly at night. For the starchless mutant slm1, timing of cell division was also independent of the photoperiod length (starting 10–12 h after sunrise). However, as opposed to the wild-type, cell division always started during the day. For both strains, growth rate increased with increased length of the light period. The slm1 mutant is capable of surviving long dark periods (up to 12 h) despite the lack of starch. In general, the slm1 mutant has a lower photosynthetic efficiency than the wild-type, with the 12:12 h LD resulting into even less efficiency than the other two LD cycles

    Determination of variability of fermentor-grown Aspergillus niger

    No full text
    Knowledge of the biological and technical variation for fermentor-grown Aspergillus niger cultures is needed to design DNA microarray experiments properly. We cultured A. niger in batch-operated fermentor vessels and induced with D-xylose. Transcript profiles were followed in detail by qPCR for 8 genes. A variance components analysis was performed on these data to determine the origin and magnitude of variation within each process step for this experiment
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