Characterization of Low Drop-Out during ageing and design for yield

2017 ◽  
Vol 76-77 ◽  
pp. 92-96 ◽  
Author(s):  
R. Lajmi ◽  
F. Cacho ◽  
E. Lauga Larroze ◽  
S. Bourdel ◽  
P. Benech ◽  
...  
Keyword(s):  
Drop Out ◽  
2020 ◽  
Author(s):  
Chi-Ming Kevin Li ◽  
Tracy M Yamawaki ◽  
Daniel R Lu ◽  
Daniel C Ellwanger ◽  
Dev Bhatt ◽  
...  

Abstract Background: Elucidation of immune populations with single-cell RNA-seq has greatly benefited the fieldof immunology by deepening the characterization of immune heterogeneity and leading to thediscovery of new subtypes. However, single-cell methods inherently suffer from limitations in therecovery of complete transcriptomes due to the prevalence of cellular and transcriptional dropoutevents. This issue is often compounded by limited sample availability and limited prior knowledge ofheterogeneity, which can confound data interpretation.Results: Here, we systematically benchmarked seven high-throughput single-cell RNA-seq methods. Weprepared 21 libraries under identical conditions of a defined mixture of two human and two murinelymphocyte cell lines, simulating heterogeneity across immune-cell types and cell sizes. We evaluatemethods by their cell recovery rate, library efficiency, sensitivity, and ability to recover expressionsignatures for each cell type. We observed higher mRNA detection sensitivity with the 10x Genomics 5’v1 and 3’ v3 methods. We demonstrate that these methods have fewer drop-out events whichfacilitates the identification of differentially-expressed genes and improves the concordance of singlecellprofiles to immune bulk RNA-seq signatures.Conclusion: Overall, our characterization of immune cell mixtures provides useful metrics, which canguide selection of a high-throughput single-cell RNA-seq method for profiling more complex immunecellheterogeneity usually found in vivo.


Author(s):  
Maurício Roberto Motta Pinto da Luz ◽  
Luiz Gustavo Ribeiro Rolando ◽  
Daniel Fábio Salvador ◽  
André Sousa

Teachers face different challenges and opportunities through distance education. We used a combination of quantitative and qualitative approaches to investigate the factors leading in-service science teachers to quit online courses. No differences were found between persistent and drop-out teachers based on their sociodemographic data and their technological skills. The dropout rates were unrelated to courses’ contents or duration. A follow-up procedure revealed that a heavy workload and technological issues accounted for most of the reasons teachers left courses. We conclude that financial incentives and reduced workload are key factors that could minimize attrition and increase persistence among Brazilian teachers.


2017 ◽  
Vol 13 (7S_Part_24) ◽  
pp. P1181-P1181
Author(s):  
Florian G. Metzger ◽  
Ulrike Suenkel ◽  
Thomas Dresler ◽  
Andreas J. Fallgatter ◽  
Gerhard W. Eschweiler ◽  
...  
Keyword(s):  

2020 ◽  
Author(s):  
Tracy M Yamawaki ◽  
Daniel R Lu ◽  
Daniel C Ellwanger ◽  
Dev Bhatt ◽  
Paolo Manzanillo ◽  
...  

Abstract Background: Elucidation of immune populations with single-cell RNA-seq has greatly benefited the field of immunology by deepening the characterization of immune heterogeneity and leading to the discovery of new subtypes. However, single-cell methods inherently suffer from limitations in the recovery of complete transcriptomes due to the prevalence of cellular and transcriptional dropout events. This issue is often compounded by limited sample availability and limited prior knowledge of heterogeneity, which can confound data interpretation. Results: Here, we systematically benchmarked seven high-throughput single-cell RNA-seq methods. We prepared 21 libraries under identical conditions of a defined mixture of two human and two murine lymphocyte cell lines, simulating heterogeneity across immune-cell types and cell sizes. We evaluate methods by their cell recovery rate, library efficiency, sensitivity, and ability to recover expression signatures for each cell type. We observed higher mRNA detection sensitivity with the 10x Genomics 5’ v1 and 3’ v3 methods. We demonstrate that these methods have fewer drop-out events which facilitates the identification of differentially-expressed genes and improves the concordance of single-cell profiles to immune bulk RNA-seq signatures.Conclusion: Overall, our characterization of immune cell mixtures provides useful metrics, which can guide selection of a high-throughput single-cell RNA-seq method for profiling more complex immune-cell heterogeneity usually found in vivo.


2020 ◽  
Author(s):  
Tracy M. Yamawaki ◽  
Daniel R. Lu ◽  
Daniel C. Ellwanger ◽  
Dev Bhatt ◽  
Paolo Manzanillo ◽  
...  

AbstractBackgroundElucidation of immune populations with single-cell RNA-seq has greatly benefited the field of immunology by deepening the characterization of immune heterogeneity and leading to the discovery of new subtypes. However, single-cell methods inherently suffer from limitations in the recovery of complete transcriptomes due to the prevalence of cellular and transcriptional dropout events. This issue is often compounded by limited sample availability and limited prior knowledge of heterogeneity, which can confound data interpretation.ResultsHere, we systematically benchmarked seven high-throughput single-cell RNA-seq methods. We prepared 21 libraries under identical conditions of a defined mixture of two human and two murine lymphocyte cell lines, simulating heterogeneity across immune-cell types and cell sizes. We evaluate methods by their cell recovery rate, library efficiency, sensitivity, and ability to recover expression signatures for each cell type. We observed higher mRNA detection sensitivity with the 10x Genomics 5’ v1 and 3’ v3 methods. We demonstrate that these methods have fewer drop-out events which facilitates the identification of differentially-expressed genes and improves the concordance of single-cell profiles to immune bulk RNA-seq signatures.ConclusionOverall, our characterization of immune cell mixtures provides useful metrics, which can guide selection of a high-throughput single-cell RNA-seq method for profiling more complex immune-cell heterogeneity usually found in vivo.


2009 ◽  
Vol 12 (01) ◽  
pp. 88-95 ◽  
Author(s):  
Ali A. Al-Meshari ◽  
Sunil L. Kokal ◽  
Peter D. Jenden ◽  
Henry I. Halpern

Summary One of the tools used for the characterization of gas reservoirs is the geochemistry of gas condensates. The fingerprinting of gas condensates by gas chromatography, in particular, may provide information regarding reservoir compartmentalization, which can be a major uncertainty at the early-field-appraisal stage. An important concern is the capture of suitable liquid samples. When the flowing bottomhole pressure falls below the dewpoint pressure, for example, condensate will drop out near the wellbore and the captured sample may not be representative of the formation fluid. We conducted two sets of tests simulating the effect(s) of gas-/liquid-phase fractionation on fingerprinting analyses:at different pressures (all below the dewpoint) at reservoir temperature (RT) region in order to simulate dropout of liquids in the near-wellbore area andto investigate the effect of variations in separator temperature and pressure. Geochemical fingerprints obtained on our laboratory-fractionated samples show that condensates obtained from gas wells with flowing bottomhole pressures below dewpoint may not be suitable for compartmentalization studies. Differences in separator pressure and temperature affect the fingerprints of gas condensates, but the effects are small and unlikely to alter conclusions regarding potential fluid-flow barriers. We suggest a number of best practices for the collection and analysis of gas condensates for fingerprinting studies.


2021 ◽  
Author(s):  
Tracy M Yamawaki ◽  
Daniel R Lu ◽  
Daniel C Ellwanger ◽  
Dev Bhatt ◽  
Paolo Manzanillo ◽  
...  

Abstract Background: Elucidation of immune populations with single-cell RNA-seq has greatly benefited the field of immunology by deepening the characterization of immune heterogeneity and leading to the discovery of new subtypes. However, single-cell methods inherently suffer from limitations in the recovery of complete transcriptomes due to the prevalence of cellular and transcriptional dropout events. This issue is often compounded by limited sample availability and limited prior knowledge of heterogeneity, which can confound data interpretation. Results: Here, we systematically benchmarked seven high-throughput single-cell RNA-seq methods. We prepared 21 libraries under identical conditions of a defined mixture of two human and two murine lymphocyte cell lines, simulating heterogeneity across immune-cell types and cell sizes. We evaluate methods by their cell recovery rate, library efficiency, sensitivity, and ability to recover expression signatures for each cell type. We observed higher mRNA detection sensitivity with the 10x Genomics 5’ v1 and 3’ v3 methods. We demonstrate that these methods have fewer drop-out events which facilitates the identification of differentially-expressed genes and improves the concordance of single-cell profiles to immune bulk RNA-seq signatures.Conclusion: Overall, our characterization of immune cell mixtures provides useful metrics, which can guide selection of a high-throughput single-cell RNA-seq method for profiling more complex immune-cell heterogeneity usually found in vivo.


Author(s):  
B. L. Soloff ◽  
T. A. Rado

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.


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