140 research outputs found
Monitoring of selected skin- and breath-borne volatile organic compounds emitted from the human body using gas chromatography ion mobility spectrometry (GC-IMS)
ISSN:1873-376XISSN:1570-0232ISSN:1572-6495ISSN:1387-227
SARS Coronavirus-2 Microneutralisation and Commercial Serological Assays Correlated Closely for Some but Not All Enzyme Immunoassays
Serological testing for SARS-CoV-2-specific antibodies provides important research and diagnostic information relating to COVID-19 prevalence, incidence and host immune response. A greater understanding of the relationship between functionally neutralising antibodies detected using microneutralisation assays and binding antibodies detected using scalable enzyme immunoassays (EIA) is needed in order to address protective immunity post-infection or vaccination, and assess EIA suitability as a surrogate test for screening of convalescent plasma donors. We assessed whether neutralising antibody titres correlated with signal cut-off ratios in five commercially available EIAs, and one in-house assay based on expressed spike protein targets. Sera from recovered patients or convalescent plasma donors who reported laboratory-confirmed SARS-CoV-2 infection (n = 200), and negative control sera collected prior to the COVID-19 pandemic (n = 100), were assessed in parallel. Performance was assessed by calculating EIA sensitivity and specificity with reference to microneutralisation. Neutralising antibodies were detected in 166 (83%) samples. Compared with this, the most sensitive EIAs were the Cobas Elecsys Anti-SARS-CoV-2 (98%) and Vitros Immunodiagnostic Anti-SARS-CoV-2 (100%), which detect total antibody targeting the N and S1 antigens, respectively. The assay with the best quantitative relationship with microneutralisation was the Euroimmun IgG. These results suggest the marker used (total Ab vs. IgG vs. IgA) and the target antigen are important determinants of assay performance. The strong correlation between microneutralisation and some commercially available assays demonstrates their potential for clinical and research use in assessing protection following infection or vaccination, and use as a surrogate test to assess donor suitability for convalescent plasma donation
Big Earth Data for Cultural Heritage in the Copernicus Era
Digital data is stepping in its golden age characterized by an increasing
growth of both classical and emerging big earth data along with trans- and multidisciplinary
methodological approaches and services addressed to the study, preservation
and sustainable exploitation of cultural heritage (CH). The availability of new
digital technologies has opened new possibilities, unthinkable only a few years ago
for cultural heritage. The currently available digital data, tools and services with
particular reference to Copernicus initiatives make possible to characterize and
understand the state of conservation of CH for preventive restoration and opened up
a frontier of possibilities for the discovery of archaeological sites from above and
also for supporting their excavation, monitoring and preservation. The different
areas of intervention require the availability and integration of rigorous information
from different sources for improving knowledge and interpretation, risk assessment
and management in order to make more successful all the actions oriented to the
preservation of cultural properties. One of the biggest challenges is to fully involve
the citizen also from an emotional point of view connecting “pixels with people”
and “bridging” remote sensing and social sensing
Consistency of the posterior distribution in generalized linear inverse problems
For ill-posed inverse problems, a regularised solution can be interpreted as
a mode of the posterior distribution in a Bayesian framework. This framework
enriches the set the solutions, as other posterior estimates can be used as a
solution to the inverse problem, such as the posterior mean that can be easier
to compute in practice. In this paper we prove consistency of Bayesian
solutions of an ill-posed linear inverse problem in the Ky Fan metric for a
general class of likelihoods and prior distributions in a finite dimensional
setting. This result can be applied to study infinite dimensional problems by
letting the dimension of the unknown parameter grow to infinity which can be
viewed as discretisation on a grid or spectral approximation of an infinite
dimensional problem. Likelihood and the prior distribution are assumed to be in
an exponential form that includes distributions from the exponential family,
and to be differentiable. The observations can be dependent. No assumption of
finite moments of observations, such as expected value or the variance, is
necessary thus allowing for possibly non-regular likelihoods, and allowing for
non-conjugate and improper priors. If the variance exists, it may be
heteroscedastic, namely, it may depend on the unknown function. We observe
quite a surprising phenomenon when applying our result to the spectral
approximation framework where it is possible to achieve the parametric rate of
convergence, i.e the problem becomes self-regularised. We also consider a
particular case of the unknown parameter being on the boundary of the parameter
set, and show that the rate of convergence in this case is faster than for an
interior point parameter.Comment: arXiv admin note: substantial text overlap with arXiv:1110.301
Hierarchical Bayesian level set inversion
The level set approach has proven widely successful in the study of inverse problems for inter- faces, since its systematic development in the 1990s. Re- cently it has been employed in the context of Bayesian inversion, allowing for the quantification of uncertainty within the reconstruction of interfaces. However the Bayesian approach is very sensitive to the length and amplitude scales in the prior probabilistic model. This paper demonstrates how the scale-sensitivity can be cir- cumvented by means of a hierarchical approach, using a single scalar parameter. Together with careful con- sideration of the development of algorithms which en- code probability measure equivalences as the hierar- chical parameter is varied, this leads to well-defined Gibbs based MCMC methods found by alternating Metropolis-Hastings updates of the level set function and the hierarchical parameter. These methods demon- strably outperform non-hierarchical Bayesian level set methods
SARS Coronavirus-2 microneutralisation and commercial serological assays correlated closely for some but not all enzyme immunoassays
Serological testing for SARS-CoV-2-specific antibodies provides important research and diagnostic information relating to COVID-19 prevalence, incidence and host immune response. A greater understanding of the relationship between functionally neutralising antibodies detected using microneutralisation assays and binding antibodies detected using scalable enzyme immunoassays (EIA) is needed in order to address protective immunity post-infection or vaccination, and assess EIA suitability as a surrogate test for screening of convalescent plasma donors. We assessed whether neutralising antibody titres correlated with signal cut-off ratios in five commercially available EIAs, and one in-house assay based on expressed spike protein targets. Sera from recovered patients or convalescent plasma donors who reported laboratory-confirmed SARS-CoV-2 infection (n = 200), and negative control sera collected prior to the COVID-19 pandemic (n = 100), were assessed in parallel. Performance was assessed by calculating EIA sensitivity and specificity with reference to microneutralisation. Neutralising antibodies were detected in 166 (83%) samples. Compared with this, the most sensitive EIAs were the Cobas Elecsys Anti-SARS-CoV-2 (98%) and Vitros Immunodiagnostic Anti-SARS-CoV-2 (100%), which detect total antibody targeting the N and S1 antigens, respectively. The assay with the best quantitative relationship with microneutralisation was the Euroimmun IgG. These results suggest the marker used (total Ab vs. IgG vs. IgA) and the target antigen are important determinants of assay performance. The strong correlation between microneutralisation and some commercially available assays demonstrates their potential for clinical and research use in assessing protection following infection or vaccination, and use as a surrogate test to assess donor suitability for convalescent plasma donation
Cumulin and FSH cooperate to regulate inhibin B and activin B production by human granulosa-lutein cells in vitro
Meeting abstract, from the 35th Annual Meeting of the European Society of Human Reproduction and Embryology
Frequency-Invariant Representation of Interaural Time Differences in Mammals
Interaural time differences (ITDs) are the major cue for localizing low-frequency sounds. The activity of neuronal populations in the brainstem encodes ITDs with an exquisite temporal acuity of about . The response of single neurons, however, also changes with other stimulus properties like the spectral composition of sound. The influence of stimulus frequency is very different across neurons and thus it is unclear how ITDs are encoded independently of stimulus frequency by populations of neurons. Here we fitted a statistical model to single-cell rate responses of the dorsal nucleus of the lateral lemniscus. The model was used to evaluate the impact of single-cell response characteristics on the frequency-invariant mutual information between rate response and ITD. We found a rough correspondence between the measured cell characteristics and those predicted by computing mutual information. Furthermore, we studied two readout mechanisms, a linear classifier and a two-channel rate difference decoder. The latter turned out to be better suited to decode the population patterns obtained from the fitted model
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