Biomimetics (Basel)
November 2024
The predictive brain hypothesis suggests that perception can be interpreted as the process of minimizing the error between predicted perception tokens generated via an internal world model and actual sensory input tokens. When implementing working examples of this hypothesis in the context of in-air sonar, significant difficulties arise due to the sparse nature of the reflection model that governs ultrasonic sensing. Despite these challenges, creating consistent world models using sonar data is crucial for implementing predictive processing of ultrasound data in robotics.
View Article and Find Full Text PDFIn this paper, we introduce SonoNERFs, a novel approach that adapts Neural Radiance Fields (NeRFs) to model and understand the echolocation process in bats, focusing on the challenges posed by acoustic data interpretation without phase information. Leveraging insights from the field of optical NeRFs, our model, termed SonoNERF, represents the acoustic environment through Neural Reflectivity Fields. This model allows us to reconstruct three-dimensional scenes from echolocation data, obtained by simulating how bats perceive their surroundings through sound.
View Article and Find Full Text PDFNavigation in varied and dynamic indoor environments remains a complex task for autonomous mobile platforms. Especially when conditions worsen, typical sensor modalities may fail to operate optimally and subsequently provide inapt input for safe navigation control. In this study, we present an approach for the navigation of a dynamic indoor environment with a mobile platform with a single or several sonar sensors using a layered control system.
View Article and Find Full Text PDFPulse-echo sensing is the driving principle behind biological echolocation as well as biologically-inspired sonar and radar sensors. In biological echolocation, a single emitter sends a self-generated pulse into the environment which reflects off objects. A fraction of these reflections are captured by two receivers as echoes, from which information about the objects, such as their position in 3D space, can be deduced by means of timing, intensity and spectral analysis.
View Article and Find Full Text PDFSalicylic acid (SA) and jasmonic acid (JA) cross-communicate in the plant immune signaling network to finely regulate induced defenses. In Arabidopsis, SA antagonizes many JA-responsive genes, partly by targeting the ETHYLENE RESPONSE FACTOR (ERF)-type transcriptional activator ORA59. Members of the ERF transcription factor family typically bind to GCC-box motifs in the promoters of JA- and ethylene-responsive genes, thereby positively or negatively regulating their expression.
View Article and Find Full Text PDFNasal colonization by Staphylococcus aureus is an important risk factor for the development of a nosocomial infection. Acquisition of nasal colonization by S. aureus increases mortality in hospitalized patients, but little is known about the transmission dynamics of S.
View Article and Find Full Text PDFInfect Control Hosp Epidemiol
February 2009
Objective: To study the acquisition and cross-transmission of Staphylococcus aureus in different intensive care units (ICUs).
Methods: We performed a multicenter cohort study. Six ICUs in 6 countries participated.
Lipid II is a crucial component in bacterial cell wall synthesis [Breukink, E., et al. (1999) Science 286, 2361-2364].
View Article and Find Full Text PDFInvasive group A streptococcal (GAS) disease re-emerged in The Netherlands in the late 1980s. To seek an explanation for this resurgence, the genetic compositions of 22 M1 and 19 M28 GAS strains isolated in The Netherlands between 1960s and the mid-1990s were analyzed by using a mixed-genome DNA microarray. During this four-decade period, M1 and especially M28 strains acquired prophages on at least eight occasions.
View Article and Find Full Text PDFWe investigated antibody responses against pneumococci of serotypes 6B, 14, and 23F in 56 children and adolescents with perinatal human immunodeficiency virus (HIV) infection who were vaccinated with 7-valent pneumococcal conjugate vaccine. Overall immune responses differed greatly between serotypes. Correlation coefficients between immunoglobulin G (IgG) measured by enzyme-linked immunosorbent assay (ELISA) and functional antibodies measured by a flow cytometry opsonophagocytosis assay (OPA) varied with serotype and time points studied.
View Article and Find Full Text PDFRecently, we reported that Streptococcus pyogenes kills Caenorhabditis elegans by the use of hydrogen peroxide (H2O2). Here we show that diverse streptococcal species cause death of C. elegans larvae in proportion to the level of H2O2 produced.
View Article and Find Full Text PDFOligosaccharide (OS)-protein conjugates are promising candidate vaccines against encapsulated bacteria, such as Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae. Although the effects of several variables such as OS chain length and protein carrier have been studied, little is known about the influence of adjuvants on the immunogenicity of OS-protein conjugates. In this study, a minimal protective trisaccharide epitope of Streptococcus pneumoniae type 3 conjugated to the cross-reacting material of diphtheria toxin was used for immunization of BALB/c mice in the presence of different adjuvants.
View Article and Find Full Text PDFAcute rheumatic fever is a serious autoimmune sequel of Streptococcus pyogenes infection. This study shows that serotype M3 and M18 S. pyogenes isolated during outbreaks of rheumatic fever have the unique capability to bind and aggregate human basement membrane collagen type IV.
View Article and Find Full Text PDFThis study aimed to characterize matrix assembly mechanisms on the surface of the human pathogen Streptococcus pyogenes. Among 125 S. pyogenes isolates, 61% were able to recruit collagen type IV via surface-bound fibronectin.
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