117,408 research outputs found
Pharyngeal function, airway protection and anesthetic agents
No full textAnesthesia related complications occur most frequently in the immediate postoperative period. The three most common conditions associated with such events are ventilatory failure, airway obstruction and aspiration. The pharynx is essential for respiration and protection of the upper airway. We hypothesized that residual concentrations of anesthetic agents (neuromuscular blocking agents (NMBA), propofol and inhaled anesthetics) impair pharyngeal function and airway protection.Using simultaneous solid-state videomanometry we studied the effects of anesthetic agents on pharyngeal function and airway protection in awake human volunteers. Partial neuromuscular block was induced by a continuous infusion of vecuronium or atracurium to train-of-four (TOF) ratios of 0.60 - 0.80, followed by spontaneous recovery. A four- to five-fold increase in the incidence of pharyngeal dysfunction with impaired airway protection and bolus penetrating to the laryngeal inlet was revealed during partial neuromuscular block. The mechanisms behind the pharyngeal dysfunction were delayed initiation of swallowing, impaired pharyngeal muscle function and impaired coordination. The upper esophageal sphincter (UES) was sensitive to partial neuromuscular block with a reduced resting tone even after recovery to a TOF ratio of > 0.90 while the inferior pharyngeal constrictor muscle was more resistant.Pharyngeal function was also evaluated in volunteers randomized to receive propofol, isoflurane or sevoflurane in subhypnotic concentrations corresponding to 0.50 an 0.25 Cp50asleep (predicted blood propofol concentration for the transition between sleep and consciousness) or 0.50 and 0.25 MACawake (alveolar concentration for the transition between sleep and consciousness). The volunteers estimated their degree of sedation on a visual analogue scale (VAS). The three agents caused a six- to nine-fold increase in the incidence of pharyngeal dysfunction, the majority of dysfunctional swallows leading to penetration of bolus to the larynx. There was a correlation between pharyngeal dysfunction and VAS degree of sedation. The effect on the pharyngeal contraction pattern was most prominent in the propofol group.Hypothesizing that a difference in nicotinic acetylcholine receptor (nAChR) density would explain the different responses to NMBA in the pharynx, the nAChR density was determined bybungarotoxin binding in muscle samples from the human cricopharyngeal muscle, the main component of the UES, and the pharyngeal constrictor muscle. We were, however, unable to detect a difference in nAChR density between the cricopharyngeal and pharyngeal constrictor muscle.The muscle fiber size and fiber type composition in the human cricopharyngeal muscle were compared with that of the pharyngeal constrictor muscle. The muscle fiber cross sectional area was generally smaller in the cricopharyngeal than the pharyngeal constrictor muscle while the muscle fiber type composition did not differ between the two muscles.In conclusion, anesthetic agents cause pharyngeal dysfunction and impaired airway protection in concentrations present during recovery. Residual neuromuscular block with TOF ratios List of scientific papersI. Eriksson LI, Sundman E, Olsson R, Nilsson L, Witt H, Ekberg O, Kuylenstierna R (1997). Functional assessment of the pharynx at rest and during swallowing in partially paralyzed humans: simultaneous videomanometry and mechanomyography of awake human volunteers. Anesthesiology. 87(5): 1035-43. https://pubmed.ncbi.nlm.nih.gov/9366453II. Sundman E, Witt H, Olsson R, Ekberg O, Kuylenstierna R, Eriksson LI (2000). The incidence and mechanisms of pharyngeal and upper esophageal dysfunction in partially paralyzed humans: pharyngeal videoradiography and simultaneous manometry after atracurium. Anesthesiology. 92(4): 977-84. https://pubmed.ncbi.nlm.nih.gov/10754616III. Sundman E, Witt H, Sandin R, Kuylenstierna R, Boden K, Ekberg O, Eriksson LI (2001). Pharyngeal function and airway protection during subhypnotic concentrations of propofol, isoflurane, and sevoflurane: volunteers examined by pharyngeal videoradiography and simultaneous manometry. Anesthesiology. 95(5): 1125-32. https://pubmed.ncbi.nlm.nih.gov/11684981IV. Sundman E, Yost SC, Margolin G, Kuylenstierna R, Ekberg O, Eriksson LI (2002). Acetylcholine receptor density in cricopharyngeal muscle and pharyngeal constrictor muscle. Acta Anaesthesiologica Scandinavica.V. Sundman E, Ansved T, Margolin G, Kuylenstierna R, Eriksson LI (2002). Fiber type composition and fiber size of the human cricopharyngeal muscle and the pharyngeal constrictor muscle. [Manuscript]</p
Nutritional enrichment effect on behavior, performance during early weaning
No full textPigs with biscuit enrichment that had no attractant had most promising early nursery daily feed intakes.This article is published as Stambuk, C., E. Sundman, G. Mercer, N. Gabler, L. Karriker, S. Millman, K. Stalder, and A. Johnson. 2021. Nutritional enrichment effect on behavior, performance during early weaning. National Hog Farmer. October 21st 2021. Copyright 2021 Informa PLC. Posted with permission
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Thermodynamic modeling of the NbeB system
No full textIn the present work, the Nb–B binary system was thermodynamically optimized. The stable phases in this system are BCC (niobium), Nb3B2, NbB, Nb3B4, Nb5B6, NbB2, B (boron) and liquid L. The borides Nb3B2, NbB, Nb3B4 and Nb5B6 and the B (boron) were modeled as stoichiometric phases and the liquid L, BCC (niobium) and NbB2 as solutions, using the sublattices model, with their excess terms described by the Redlich–Kister polynomials. The Gibbs energy coefficients were optimized based on the experimental values of enthalpy of formation, low temperature specific heat, liquidus temperatures and temperatures of invariant transformations. The calculated Nb–B diagram reproduces well the experimental values from the literature
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Computational Thermodynamics and Kinetics in Materials Modelling and Simulations
No full textOver the past two decades, Computational Thermodynamics and Kinetics have been tremendously contributed to materials modeling and simulations and the demands on quantitative conceptual design and processing of various advanced materials arisen from various industries and academic institutions involved in materials manufacturing, engineering and applications are still rapidly increasing
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
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