Mapping the Spatial and Temporal Dynamics of Sensorimotor Integration During the Perception and Performance of Wallowing

Similar to other complex sequences of muscle activity, swallowing relies heavily upon ‘sensorimotor integration.’ It is well known that the premotor cortex and primary sensorimotor cortices provide critical sensorimotor contributions that help control the strength and timing of swallowing muscle effectors. However, the temporal dynamics of sensorimotor integration remains unclear, even when performed normally without neurological compromise. Recent advances in EEG analysis blind source separation techniques via independent component analysis offer a novel and exciting opportunity to measure cortical sensorimotor activity in realtime during swallowing, concurrently with muscle activity during swallow initiation. In the current study, mu components were identified, with characteristic alpha (~10 Hz) and beta (~20 Hz) frequency bands. Spectral power within these frequency bands are known to index somatosensory and motor activity, respectively. Twenty-five adult participants produced swallowing and tongue tapping (motor control) tasks. Additionally they were asked to watch a video depicting swallowing and a scrambled kaleidoscope (perceptual control) version of this same video. Independent component analysis of raw EEG signals identified bilateral clusters of mu components, maximally localized to the premotor cortex (BA6) in 19 participants during the production and the perception tasks. Event related spectral perturbation (ERSP) analysis was used to identify spectral power within alpha and beta peaks of the mu cluster across time. Alpha and beta event-related desynchronization (ERD), indicative of somatosensory and motor activity, was revealed for both tongue tapping and swallowing beginning at ~500 ms following a visual cue to “go.” However, the patterns of ERD are stronger (pFD

Objective physiological measures of lingual and jaw function in healthy individuals and individuals with dysphagia due to neurodegenerative diseases

Swallowing is a neuromuscular process that involves a complex sequence of sensorimotor events, which are executed to efficiently and safely transport food and liquid from the mouth to the stomach. Safe oropharyngeal swallowing involves the activation, modulation, and coordination of oral, pharyngeal, laryngeal, and esophageal structures and musculature. Impaired or atypical patterns of swallowing are considered characteristic of a swallowing disorder, otherwise referred to as dysphagia, and affect the performance of all stages, i.e., oral preparatory, oral transit, pharyngeal, and esophageal. Lingual and jaw musculature play critical roles in mediating swallowing function, particularly during the oral preparatory and oral transit stages. This current study presents an adapted simple, economical, and clinically relevant protocol that may be used to quantify lingual and jaw movement in healthy and disordered swallowing, and thus track physiological changes in lingual and jaw musculature over time in individuals with dysphagia due to neurodegenerative diseases. Jaw ROM tasks, adapted from [1,2], were adapted and utilized to measure the jaw during three postures: opening, lateralization, and protrusion. Adapting a scale developed by Lazarus and colleagues [3], objective lingual ROM values were obtained using the TheraBite® tool [4] and categorized according to functional status. Upon methodological adaption and collation of lingual ROM and jaw ROM tasks, a comprehensive set of images clearly depicting each procedural task and a clinically friendly form were developed to guide data collection for research and clinical use

Leadership in School Social Work: Implications for Promoting the Preparedness of Tomorrow’s Practitioners

Current research suggests that leadership skills in the field of school social work are valuable and needed. However, these skills are not always clearly outlined by governing entities as a result of little examination and research. This article examines differences of perceptions toward and engagement in professional leadership skills among school social work practitioners across the United States (N = 686). Using descriptive and multivariate methods, this paper examines practitioner perceptions toward and engagement in school-based leadership and what this leadership looks like in today’s schools. Findings call for educators and practitioners to advocate for the incorporation of leadership training, culturally sensitive cross-discipline collaboration, and preparedness guidelines in both generalist bachelor- and master-level social work curricula in which students are trained to work in school settings. Moreover, access to training and availability of resources pertaining to leadership appear to be a point of concern. Implications for social work practice, education, and research are discussed

Recognition of nucleotides and peptides using designed betahairpin peptides and dynamic combinatorial chemistry

Non-covalent interactions contribute to the stability and formation of biomolecules, e.g. proteins, DNA, and RNA. More relevant to this dissertation, they also contribute to the interaction between these biomolecules, e.g. protein-protein, protein-RNA, and protein-DNA interactions. This work describes the use of model systems (peptide and small molecule) to mimic protein-RNA and protein-protein interactions. This dissertation is divided into three parts. The first part describes the attempted use of designed beta-hairpin peptides to selectively bind 7mGTP. Despite attempts using different binding techniques (fluorescence titration, microcalorimetry, and NMR titration), the binding of 7mGTP by the beta-hairpin peptides could not be quantified. The second part describes the use of designed beta-hairpin peptides for recognition of polyproline (PPII) helices in a model system. This work demonstrates the use of disulfide exchange to investigate non-covalent interactions in a peptide model system. The third part describes the development and the use of dynamic combinatorial chemistry (DCC) mediated by disulfide exchange. The development of analytical methodology using ultra performance liquid chromatography coupled with mass spectrometry analysis (UPLC/MS) is described. DCC was used to synthesize and identify receptors for both nucleotides and peptides containing a lysine residue with different methylation states

Native architecture of the Chlamydomonas chloroplast revealed by in situ cryo-electron tomography

Chloroplast function is orchestrated by the organelle's intricate architecture. By combining cryo-focused ion beam milling of vitreous Chlamydomonas cells with cryo-electron tomography, we acquired three-dimensional structures of the chloroplast in its native state within the cell. Chloroplast envelope inner membrane invaginations were frequently found in close association with thylakoid tips, and the tips of multiple thylakoid stacks converged at dynamic sites on the chloroplast envelope, implicating lipid transport in thylakoid biogenesis. Subtomogram averaging and nearest neighbor analysis revealed that RuBisCO complexes were hexagonally packed within the pyrenoid, with similar to 15 nm between their centers. Thylakoid stacks and the pyrenoid were connected by cylindrical pyrenoid tubules, physically bridging the sites of light-dependent photosynthesis and light-independent carbon fixation. Multiple parallel minitubules were bundled within each pyrenoid tubule, possibly serving as conduits for the targeted one-dimensional diffusion of small molecules such as ATP and sugars between the chloroplast stroma and the pyrenoid matrix

Dynamic Characteristics of Comares Palace in the Alhambra

This paper describes the geotechnical investigations that have been conducted to characterize the static and dynamic properties of the ground, the foundation and the structure\u27s material of the Comares tower in the Alhambra palace. The Gmax values of the different materials were determined using seismic refraction, P-wave transmission tomography, cross-hole and down-hole tests. To obtain the variation of the shear moduli with strain amplitude surface wave and cyclic horizontal plate loading tests were performed in several trenches excavated in the immediate neighborhood. The analysis of the structure response to M = 5 earthquakes recently recorded at the top and the bottom of the Tower allowed to check the dynamic properties of the materials estimated previously

Root-Locus Analysis of Delayed First and Second Order Systems

For finite dimensional linear system the root-locus method is well established however for the case of delayed systems the method has some problems due to the transcendental term involved. This work intends to illustrate the problems that arises when a root-locus diagram is performed as well as to develop a Matlab function that provides the root-locus diagram for delayed low order systems. In this way, some comments about the problems that should be tackled to obtain a generalization of the computational method for delayed systems with real m poles and n zero

Pair-induced spectral changes and variability in compact X-ray sources

Inverse Compton scattering of ultraviolet photons by GeV electrons produces γ-rays which in turn create electron–positron pairs if the source is sufficiently compact. The pairs modify the emergent radiation spectrum through their own inverse Compton scattering and through thermal Comptonization after they have cooled to sub-relativistic temperatures. Recent calculations of spectral reprocessing under these conditions are extended to situations in which the Thomson optical depth of the pair plasma exceeds unity, and to demonstrate time-dependent behaviour explicitly. The relevance of our results to X-ray observations of active galactic nuclei, binary X-ray sources and γ-ray bursters is discussed briefly