The Impact of Torso Signal Processing on Noninvasive Electrocardiographic Imaging Reconstructions

Goal: To evaluate state-of-the-art signal processing methods for epicardial potential-based noninvasive electrocardiographic imaging reconstructions of single-site pacing data. Methods: Experimental data were obtained from two torso-tank setups in which Langendorff-perfused hearts (n = 4) were suspended and potentials recorded simultaneously from torso and epicardial surfaces. 49 different signal processing methods were applied to torso potentials, grouped as i) high-frequency noise removal (HFR) methods ii) baseline drift removal (BDR) methods and iii) combined HFR+BDR. The inverse problem was solved and reconstructed electrograms and activation maps compared to those directly recorded. Results: HFR showed no difference compared to not filtering in terms of absolute differences in reconstructed electrogram amplitudes nor median correlation in QRS waveforms (p > 0.05). However, correlation and mean absolute error of activation times and pacing site localization were improved with all methods except a notch filter. HFR applied post-reconstruction produced no differences compared to pre-reconstruction. BDR and BDR+HFR significantly improved absolute and relative difference, and correlation in electrograms (p < 0.05). While BDR+HFR combined improved activation time and pacing site detection, BDR alone produced significantly lower correlation and higher localization errors (p < 0.05). Conclusion: BDR improves reconstructed electrogram morphologies and amplitudes due to a reduction in lambda value selected for the inverse problem. The simplest method (resetting the isoelectric point) is sufficient to see these improvements. HFR does not impact electrogram accuracy, but does impact post-processing to extract features such as activation times. Removal of line noise is insufficient to see these changes. HFR should be applied post-reconstruction to ensure over-filtering does not occur

Potential environmental transmission routes of SARS-CoV-2 inside a large meat processing plant experiencing COVID-19 clusters

Worldwide exceptionally many COVID-19 clusters were observed in meat processing plants. Many contributing factors, promoting transmission, were suggested, including climate conditions in cooled production rooms favorable for environmental transmission but actual sampling studies are lacking. We aimed to assess SARS-CoV-2 contamination of air and surfaces to gain insight in potential environmental transmission in a large Dutch meat processing plant experiencing COVID-19 clusters. We performed SARS-CoV-2 screening of workers operating in cooled production rooms and intensive environmental sampling during a two-week study period in June 2020. Sampling of air (both stationary and personal), settling dust, ventilation systems, and sewage was performed. Swabs were collected from high-touch surfaces and workers’ hands. Screening of workers was done using oronasopharyngeal swabs. Samples were tested for presence of SARS-CoV-2 RNA by RT-qPCR. Of the 76 (predominantly asymptomatic) workers tested, 27 (35.5%) were SARS-CoV-2 RNA positive with modest to low viral loads (Ct≥29.7). In total, 6 out of 203 surface swabs were positive (Ct ≥38), being swabs taken from communal touchscreens/handles. One of the 12 personal air samples and one of the 4 sewage samples were positive, RNA levels were low (Ct≥38). All other environmental samples tested negative. Although one-third of workers tested SARS-CoV-2 RT-PCR positive, environmental contamination was limited. Hence widespread transmission of SARS-CoV-2 via air and surfaces was considered unlikely within this plant at the time of investigation in the context of strict COVID-19 control measures in place

Context-dependent changes in functional connectivity of auditory cortices during the perception of object words

Contains fulltext : 102395.pdf (publisher's version ) (Open Access)Embodied theories hold that cognitive concepts are grounded in our sensorimotor systems. Specifically, a number of behavioral and neuroimaging studies have buttressed the idea that language concepts are represented in areas involved in perception and action [Pulvermueller, F. Brain mechanisms linking language and action. Nature Reviews Neuroscience, 6, 576-582, 2005; Barsalou, L. W. Perceptual symbol systems. Behavioral and Brain Sciences, 22, 577-660, 1999]. Proponents of a strong embodied account argue that activity in perception/action areas is triggered automatically upon encountering a word and reflect static semantic representations. In contrast to what would be expected if lexical semantic representations are automatically triggered upon encountering a word, a number of studies failed to find motor-related activity for words with a putative action-semantic component [Raposo, A., Moss, H. E., Stamatakis, E. A., & Tyler, L. K. Modulation of motor and premotor cortices by actions, action words and action sentences. Neuropsychologia, 47, 388-396, 2009; Rueschemeyer, S.-A., Brass, M., & Friederici, A. D. Comprehending prehending: Neural correlates of processing verbs with motor stems. Journal of Cognitive Neuroscience, 19, 855-865, 2007]. In a recent fMRI study, Van Dam and colleagues [Van Dam, W. O., Van Dijk, M., Bekkering, H., & Rueschemeyer, S.-A. Flexibility in embodied lexical-semantic representations. Human Brain Mapping, in press] showed that the degree to which a modality-specific region contributes to a representation considerably changes as a function of context. In the current study, we presented words for which both motor and visual properties (e.g., tennis ball, boxing glove) were important in constituting the concept. Our aim was to corroborate on earlier findings of flexible and context-dependent language representations by testing whether functional integration between auditory brain regions and perception/action areas is modulated by context. Functional connectivity was investigated by means of a psychophysiological interaction analysis, in which we found that bilateral superior temporal gyrus was more strongly connected with brain regions relevant for coding action information: (1) for Action Color words vs. Abstract words, and (2) for Action Color words presented in a context that emphasized action vs. a context that emphasized color properties.12 p

Program Transformation with Scoped Dynamic Rewrite Rules

The applicability of term rewriting to program transformation is limited by the lack of control over rule application and by the context-free nature of rewrite rules. The first problem is addressed by languages supporting user-definable rewriting strategies. The second problem is addressed by the extension of rewriting strategies with scoped dynamic rewrite rules. Dynamic rules are defined at run-time and can access variables available from their definition context. Rules defined within a rule scope are automatically retracted at the end of that scope. In this paper we explore the design space of dynamic rules, their application to transformation problems, and their implementation. The technique is formally defined by extending the operational semantics underlying the program transformation language Stratego, and illustrated by means of several program tranformations in Stratego, including constant propagation, bound variable renaming, dead code elimination, function inlining, and function specialization

Inferring the Evolutionary History of Your Favorite Protein : A Guide for Molecular Biologists

Comparative genomics has proven a fruitful approach to acquire many functional and evolutionary insights into core cellular processes. Here it is argued that in order to perform accurate and interesting comparative genomics, one first and foremost has to be able to recognize, postulate, and revise different evolutionary scenarios. After all, these studies lack a simple protocol, due to different proteins having different evolutionary dynamics and demanding different approaches. The authors here discuss this challenge from a practical (what are the observations?) and conceptual (how do these indicate a specific evolutionary scenario?) viewpoint, with the aim to guide investigators who want to analyze the evolution of their protein(s) of interest. By sharing how the authors draft, test, and update such a scenario and how it directs their investigations, the authors hope to illuminate how to execute molecular evolution studies and how to interpret them. Also see the video abstract here https://youtu.be/VCt3l2pbdbQ

Een zuigeling met een zwelling op het hoofd: de sub-aponeurotische vochtcollectie

A sub-aponeurotic fluid collection (an extracranial fluid accumulation between the galea aponeurotica and the periostium of the scalp) of 2 week duration was observed in a 2.5-month-old male infant. In contrast to a subgaleal bleeding, which occurs on the first day after birth and is of a progressive nature, swelling caused by sub-aponeurotic fluid collection does not occur until a few weeks after birth and shows a benign course. The exact etiological mechanism of this fluid collection is unknown. It is probable that temporary (micro) fluid fistula, as a result of birth trauma, plays a role. Management is conservative, and complete reabsorption can be expected within a few weeks to months at the most

An infant with a cranial swelling:sub-aponeurotic fluid collection

A sub-aponeurotic fluid collection (an extracranial fluid accumulation between the galea aponeurotica and the periostium of the scalp) of 2 week duration was observed in a 2.5-month-old male infant. In contrast to a subgaleal bleeding, which occurs on the first day after birth and is of a progressive nature, swelling caused by sub-aponeurotic fluid collection does not occur until a few weeks after birth and shows a benign course. The exact etiological mechanism of this fluid collection is unknown. It is probable that temporary (micro) fluid fistula, as a result of birth trauma, plays a role. Management is conservative, and complete reabsorption can be expected within a few weeks to months at the most.</p