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Stationary Signal

Nigel Gebodh, Zeinab Esmaeilpour, Devin Adair, Kenneth Chelette, Jacek Dmochowski, Adam J Woods, Emily S Kappenman, Lucas C Parra, Marom Bikson
Online imaging and neuromodulation is invalid if stimulation distorts measurements beyond the point of accurate measurement. In theory, combining transcranial Direct Current Stimulation (tDCS) with electroencephalography (EEG) is compelling, as both use non-invasive electrodes and image-guided dose can be informed by the reciprocity principle. To distinguish real changes in EEG from stimulation artifacts, prior studies applied conventional signal processing techniques (e.g. high-pass filtering, ICA). Here, we address the assumptions underlying the suitability of these approaches...
October 12, 2018: NeuroImage
Marco Kai, Birgit Piechulla
Sodorifen is the major volatile of Serratia plymuthica 4Rx13. It is assumed to be a long-distance communication signal. However, so far the emission patterns of sodorifen had been studied using mono-cultures of S. plymuthica 4Rx13 neglecting that in natura bacteria live in communities. Here, we show that the structured co-cultivation of S. plymuthica 4Rx13 and Bacillus subtilis B2g in a low-diversity model community grown under nutrient rich conditions led to quantitative changes in sodorifen emission compared to self-paired mono-cultivations...
October 11, 2018: FEMS Microbiology Letters
Felipe Alves de Almeida, Deisy Guimarães Carneiro, Tiago Antônio de Oliveira Mendes, Edvaldo Barros, Uelinton Manoel Pinto, Leandro Licursi de Oliveira, Maria Cristina Dantas Vanetti
Quorum sensing is a cell-cell communication mechanism mediated by chemical signals that leads to differential gene expression in response to high population density. Salmonella is unable to synthesize the autoinducer-1 (AI-1), N-acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. This study aimed to evaluate the fatty acid and protein profiles of Salmonella enterica serovar Enteritidis PT4 578 throughout time of cultivation in the presence of AHL...
2018: PloS One
Hongyin Shi, Saixue Xia, Qi Qin, Ting Yang, Zhijun Qiao
As a powerful signal processing tool for imaging moving targets, placing radar on a non-stationary platform (such as an aerostat) is a future direction of Inverse Synthetic Aperture Radar (ISAR) systems. However, more phase errors are introduced into the received signal due to the instability of the radar platform, making it difficult for popular algorithms to accurately perform motion compensation, which leads to severe effects in the resultant ISAR images. Moreover, maneuvering targets may have complex motion whose motion parameters are unknown to radar systems...
October 5, 2018: Sensors
Benjamin Dieudonné, Tom Francart
OBJECTIVES: To establish a framework to unambiguously define and relate the different spatial effects in speech understanding: head shadow, redundancy, squelch, spatial release from masking (SRM), and so on. Next, to investigate the contribution of interaural time and level differences to these spatial effects in speech understanding and how this is influenced by the type of masking noise. DESIGN: In our framework, SRM is uniquely characterized as a linear combination of head shadow, binaural redundancy, and binaural squelch...
October 5, 2018: Ear and Hearing
Iris Kyranou, Sethu Vijayakumar, Mustafa Suphi Erden
Surface Electromyography (EMG)-based pattern recognition methods have been investigated over the past years as a means of controlling upper limb prostheses. Despite the very good reported performance of myoelectric controlled prosthetic hands in lab conditions, real-time performance in everyday life conditions is not as robust and reliable, explaining the limited clinical use of pattern recognition control. The main reason behind the instability of myoelectric pattern recognition control is that EMG signals are non-stationary in real-life environments and present a lot of variability over time and across subjects, hence affecting the system's performance...
2018: Frontiers in Neurorobotics
Arnab Basu, Kate E Shields, Christopher S Eickhoff, Daniel F Hoft, Mee-Ngan F Yap
The translationally silent 100S ribosome is a poorly understood form of the dimeric 70S complex that is ubiquitously found in all bacterial phyla. Eliminating the hibernating 100S ribosome leads to translational derepression, ribosome instability, antibiotic sensitivity, and biofilm defects in some bacteria. In Firmicutes, such as the opportunistic pathogen Staphylococcus aureus , a 190-amino acids protein called <u>h</u> ibernating- <u>p</u> romoting <u>f</u> actor (HPF) dimerizes and conjoins two 70S ribosomes through a direct interaction between the HPF homodimer, with each HPF monomer tethered on an individual 70S complex...
October 8, 2018: Journal of Bacteriology
Yi Yang, Yunci Zhang, Chang Liu, Zhenni Ji, Yuxin Yin, Tingting Chu, Jing Tian, Yoichiro Ito
In our recent study, the design and performance of type-I counter-current chromatography (CCC) were changed and improved by multilayer coil. In the present study, the performance of protein separation using the multilayer coil configuration in type-I CCC was investigated under various flow rates. In order to overcome the noise signal interrupting the target peaks, a hollow fiber membrane dialyzer was inserted between CCC column outlet and inlet of the monitor. The separation was performed with a two-phase solvent system composed of polyethylene glycol 1000/dibasic potassium phosphate each at 12...
September 27, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Marco Turco, Juan José Rosa-Cánovas, Joaquín Bedia, Sonia Jerez, Juan Pedro Montávez, Maria Carmen Llasat, Antonello Provenzale
The observed trend towards warmer and drier conditions in southern Europe is projected to continue in the next decades, possibly leading to increased risk of large fires. However, an assessment of climate change impacts on fires at and above the 1.5 °C Paris target is still missing. Here, we estimate future summer burned area in Mediterranean Europe under 1.5, 2, and 3 °C global warming scenarios, accounting for possible modifications of climate-fire relationships under changed climatic conditions owing to productivity alterations...
October 2, 2018: Nature Communications
Shinya Sugimoto, Ken-Ichi Arita-Morioka, Akari Terao, Kunitoshi Yamanaka, Teru Ogura, Yoshimitsu Mizunoe
Biofilms are intricate communities of microorganisms embedded in a self-produced matrix of extracellular polymer, which provides microbes survival advantages in stressful environments and can cause chronic infections in humans. Curli are functional amyloids that assemble on the extracellular surface of enteric bacteria such as Escherichia coli during biofilm development and colonization. The molecular chaperone DnaK, a bacterial Hsp70 homologue, promotes curli biogenesis via unknown mechanism(s). Here we show that DnaK increases the expression of CsgA and CsgB-the major and minor structural components of curli, respectively-via a quantity and quality control of RpoS, a stationary phase-specific alternative sigma factor regulating bacterial transcription, and CsgD, the master transcriptional regulator of curli formation...
2018: Communications biology
Celia Mayer, Andrea Muras, Manuel Romero, María López, María Tomás, Ana Otero
Acinetobacter baumannii presents a typical lux I/ lux R quorum sensing (QS) system ( abaI / abaR ) but the acyl-homoserine lactone (AHL) signal profile and factors controlling the production of QS signals in this species have not been determined yet. A very complex AHL profile was identified for A. baumannii ATCC17978 as well as for A. nosocomialis M2, but only when cultivated under static conditions, suggesting that surface or cell-to-cell contact is involved in the activation of the QS genes. The analysis of A...
2018: Frontiers in Cellular and Infection Microbiology
Jeremi K Ochab, Wojciech Tarnowski, Maciej A Nowak, Dante R Chialvo
The study of correlations between brain regions is an important chapter of the analysis of large-scale brain spatiotemporal dynamics. In particular, novel methods suited to extract dynamic changes in mutual correlations are needed. Here we scrutinize a recently reported metric dubbed "Multiplication of Temporal Derivatives" (MTD) which is based on the temporal derivative of each time series. The formal comparison of the MTD formula with the Pearson correlation of the derivatives reveals only minor differences, which we find negligible in practice...
September 26, 2018: NeuroImage
Ludivine Ferey, Sara Albe Slabi, Claude-Eric Roy, Philippe Barthelemy, Karen Gaudin
Today, one of the most popular strategies in drug delivery is the encapsulation of therapeutic agents in supramolecular nanosystems formed from amphiphilic molecules. Synthetic nucleoside-lipids, composed of one nucleoside and lipidic chains, constitute promising new amphiphilic excipients under research in the field of pharmaceutical and biomedical applications. The aim of this work was to study the chromatographic behavior of these nucleoside-lipids in reversed-phase HPLC to establish appropriate chromatographic conditions for their analysis in drug delivery systems...
September 28, 2018: Analytical and Bioanalytical Chemistry
María A Chiesa, Roxana A Roeschlin, María A Favaro, Facundo Uviedo, Laura Campos-Beneyto, Rodrigo D'Andrea, José Gadea, María R Marano
Citrus is an economically important fruit crop that is severely afflicted by citrus canker, a disease caused by Xanthomonas citri ssp. citri (X. citri); thus, new, sustainable strategies to manage this disease are needed. Although all Citrus spp. are susceptible to this pathogen, they are resistant to other Xanthomonas species, exhibiting nonhost resistance (NHR), for example, to the brassica pathogen X. campestris pv. campestris (Xcc) and gene-for-gene host defense response (HDR) to the canker-causing X. fuscans ssp...
September 27, 2018: Molecular Plant Pathology
Mehdi Maadooliat, Ying Sun, Tianbo Chen
In this paper, we develop a method for the simultaneous estimation of spectral density functions (SDFs) for a collection of stationary time series that share some common features. Due to the similarities among the SDFs, the log-SDF can be represented using a common set of basis functions. The basis shared by the collection of the log-SDFs is estimated as a low-dimensional manifold of a large space spanned by a prespecified rich basis. A collective estimation approach pools information and borrows strength across the SDFs to achieve better estimation efficiency...
September 26, 2018: Statistics in Medicine
Antonio J Ibáñez-Molina, Vanessa Lozano, María F Soriano, José I Aznarte, Carlos J Gómez-Ariza, M T Bajo
Introduction: Patients with schizophrenia show cognitive deficits that are evident both behaviourally and with EEG recordings. Recent studies have suggested that non-linear analyses of EEG might more adequately reflect the complex, irregular, non-stationary behavior of neural processes than more traditional ERP measures. Non-linear analyses have been mainly applied to EEGs from patients at rest, whereas differences in complexity might be more evident during task performance. Objective: We aimed to investigate changes in non-linear brain dynamics of patients with schizophrenia during cognitive processing...
2018: Frontiers in Physiology
Robyn L Miller, Anees Abrol, Tulay Adali, Yuri Levin-Schwarz, Vince D Calhoun
Studies of resting state functional MRI (rs-fRMI) are increasingly focused on "dynamics", or on those properties of brain activation that manifest and vary on timescales shorter than the scan's full duration. This shift in focus has led to a flurry of interest in developing hypothesis testing frameworks and null models applicable to the dynamical setting. Thus far however, these efforts have been weakened by a number of crucial shortcomings that are outlined and discussed in this article. We focus here on aspects of recently proposed null models that, we argue, are poorly formulated relative to the hypotheses they are designed to test, i...
2018: Frontiers in Neuroscience
Lin Zhang, Taoyun Zhou, Baowang Lian
Considering the radio-based indoor positioning system pertaining to signal degradation due to the environmental factors, and rising popularity of IP (Internet Protocol) cameras in cities, a novel fusion of inertial measurement units (IMUs) with external IP cameras to determine the positions of moving users in indoor environments is presented. This approach uses a fine-tuned Faster R-CNN (Region Convolutional Neural Network) to detect users in images captured by cameras, and acquires visual measurements including ranges and angles of users with respect to the cameras based on the proposed monocular vision relatively measuring (MVRM) method...
September 17, 2018: Sensors
Erin L Barnhart, Irving E Wang, Huayi Wei, Claude Desplan, Thomas R Clandinin
Many animals guide their movements using optic flow, the displacement of stationary objects across the retina caused by self-motion. How do animals selectively synthesize a global motion pattern from its local motion components? To what extent does this feature selectivity rely on circuit mechanisms versus dendritic processing? Here we used in vivo calcium imaging to identify pre- and postsynaptic mechanisms for processing local motion signals in global motion detection circuits in Drosophila. Lobula plate tangential cells (LPTCs) detect global motion by pooling input from local motion detectors, T4/T5 neurons...
October 10, 2018: Neuron
Garrett Hellinghausen, M Farooq Wahab, Daniel W Armstrong
In some cases, trace component analysis only requires a sensitive and high-resolution mass spectrometer. However, enantiomers must be completely separated to be differentiated with a mass spectrometer, which is highly dependent on the stationary-mobile phase composition. In case of a challenging chiral separation, instead of trying new columns for screening purpose, resolution enhancement techniques could be used to resolve partially overlapping peaks. A well-known enhancement method is the power law, which increases the linear dynamic range of each analyte and reduces excessive noise...
September 1, 2018: Journal of Chromatography. A
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