4,020 research outputs found
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
Guidelines for Measuring and Reporting Environmental Parameters for Experiments in Greenhouses
No full textThe importance of appropriate, accurate measurement and reporting of environmental parameters in plant sciences is a significant aspect of quality assurance for all researchers and their research. There is a clear need for ensuring research across the world can be compared, understood and where necessary replicated by fellow researchers. A common set of guidelines to educate, assist and encourage comparativeness is of great importance. On the other hand, the level of effort and attention to detail by an individual researcher should be commensurate with the particular research being conducted. For example, a researcher focusing on interactions of light and temperature should measure all relevant parameters and report a measurement summary that includes sufficient detail allowing for replication. Such detail may be less relevant when the impact of environmental parameters on plant growth and development is not the main research focus. However, it should be noted that the environmental experience of a plant during production can have significant impact when subsequent experiments investigate plants at a molecular, biochemical or genetic level or where species interactions are considered. Thus, researchers are encouraged to make a critical assessment of what parameters are of primary importance in their research and these parameters should be measured and reported.© 2015 Both et al. This article is distributed under terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons License, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0) applies to the data made available in this article, unless otherwise stated.Peer reviewe
LabPatch, an acquisition and analysis program for patch-clamp electrophysiology
No full text An acquisition and analysis program, “LabPatch,” has been developed for use in patch-clamp research. LabPatch controls any patch-clamp amplifier, acquires and records data, runs voltage protocols, plots and analyzes data, and connects to spreadsheet and database programs. Controls within LabPatch are grouped by function on one screen, much like an oscilloscope front panel. The software is mouse driven, so that the user need only point and click. Finally, the ability to copy data to other programs running in Windows 95/98, and the ability to keep track of experiments using a database, make LabPatch extremely versatile. The system requirements include Windows 95/98, at least a 100-MHz processor and 16 MB RAM, a data acquisition card, digital-to-analog converter, and a patch-clamp amplifier. LabPatch is available free of charge at http://www.fhs.mcmaster.ca/huizinga/ . </jats:p
Figure 1: Effect of TNF and IL-10 on the clearance of
No full textHospital Leiden, Netherlands; and Department of Psychonomics, Free University Amsterdam (D I Boomsma PhD) Correspondence to: Dr Rudi G J Westendorp, Department of Clinical Epidemiology, University Hospital Leiden, C0-P, 2300 RC Leiden, Netherlands Genetic influence on cytokine production and fatal meningococcal disease Rudi G J Westendorp, Jan A M Langermans, Tom W J Huizinga, Abdul H Elouali, Cornelis L Verweij, Dorret I Boomsma, Jan P Vandenbrouke Introduction There is a strong genetic component to fatal infectious disease. Adoptees have a fivefold increased risk of fatal infectious disease if a biological parent has died from infection. 1 By contrast, death from infection in an adoptive parent resulted in no excess relative risks of death. Our knowledge of the factors that contribute to this genetic susceptibility is limited. Tumour necrosis factor (TNF) is a decisive proinflammatory mediator in the host defence to infection. Treatment with recombinant human TNF can pr
Jan Křtitel Vaňhal- Concerto in D Major, Life and Work
No full textThe thesis discusses a Czech composer living in Vienna, Jan Křtitel Vaňhal, and his concerto D major for double bass and orchestra. The aim was to contribute to better understanding of the piece so that it would be easier for many interprets to study it. The first part of the thesis focuses on the basic biography of the author and it outlines the current state of research. Chapters about the galant style and the development of classicist concerto in the second part are meant to clarify the musicological context of the piece. The third part is the core of the entire thesis. It analyses the concerto D major in the adaptation for double bass and piano and it aims to assess Vaňhal’s composition style
Assessment of Healthy Colonic Motility Patterns, Colonic Dysmotility, and its Association with Autonomic Nervous System Dysfunction
No full textIntroduction: Functional motility disorders of the colon are poorly defined. Hence, patients with chronic colonic motor dysfunction are treated or undergo surgery without proper diagnosis. Most colonic motility assessment centers around the largest propagating motor pattern in the colon- the High Amplitude Propagating Pressure Wave (HAPW). However, there is no consensus regarding a definition of this important motor pattern. Additionally, no consideration is given to other aspects of colonic motility such as colo-ano-rectal coordination and control by the autonomic nervous system (ANS). The aim of this thesis was to improve understanding of HAPWs and other features of colonic motility in health and constipation, understand how autonomic dysfunction is related to observations in patients, and evaluate the effect of neuromodulation of the ANS. Methods: Motility was assessed in healthy volunteers and patients using water-perfused High Resolution Colonic Manometry (HRCM). To assess the association between ANS and colonic motor activity Heart Rate Variability (HRV) was measured in patients. Spatiotemporal maps were created using HRCM to analyse and quantify colonic motor activity following baseline, and interventions which included proximal balloon distention, meal, and rectal bisacodyl. Low-Level Light Therapy (LLLT) was also applied during HRCM as a method of neuromodulation, to observe its effect on colonic motility. Results: Normal HAPWs are those which have an amplitude of more than 50 mmHg and belong to one of 3 categories: proximally originating, proximal continuing, and transverse/descending. The best intervention sequence to generate these during HRCM assessment is baseline, proximal balloon distention, meal, rectal bisacodyl. Based on their responses to these interventions and the type of HAPWs present, patients could be classified into strong responder, weak responder and non-responder groups. Overall, patients in the strong responder group were most similar to healthy volunteers both with regard to motility and ANS control. Conversely, the weak and non-responders had showed decreased or no motility with decreased parasympathetic input and occasionally sympathetic inhibition. Additionally, other features of motility such as the sphincter of O'Beirne, and lack of colo-ano-rectal coordination were found to lead to constipation even in presence of normal HAPWs. LLLT shows promise in initiating colonic motor activity through neuromodulation of the sacral defecation center. Conclusions: HAPWs can be defined into one of three categories and used to categorize patients based on their HAPW response to different interventions. However, other aspects of colonic motility such as the colo-ano-rectal coordination and autonomic nervous system control of colonic motility should be taken into consideration in diagnosis of constipation, as they can point towards more non-invasive treatment methods such as neuromodulation using LLLT.ThesisMaster of Science in Medical Sciences (MSMS
Jan Novák : Orpheus et Eurxdice "
No full textIn her graduation thesis, the author discusses the interpretation and difficulties encountered learning and performing Jan Novak´s chamber cantata " Orpheus et Eurydice". She also touches upon Novakś life, including his character and human side, as well as his interest in Latin. Also included is information about the viola d´amoure, which occupies an important position in this cantata
Intrinsic electrophysiological properties of interstitial cells of Cajal and smooth muscle cells
No full textThe gastrointestinal (GI) tract is a hollow tubular organ that runs through the length of the central body. To move, mix, and compartmentalize ingesta through this tract, different patterns of motility are needed. This thesis is concerned with the myogenic control of motility through the pacemaker network of interstitial cells of Cajal (ICC) and the smooth muscle cells (SMC). Using patch clamp techniques, the electrophysiological properties of single ICC and SMC were examined. Previous research suggested the possibility of a specialized cell type generating the pacemaker slow wave potentials: the network of ICC that resides in the Auerbach's plexus region of the small intestine. An isolation procedure was developed and optimized to harvest single ICC that can survive short term culture and allow examination by patch clamp. Single cell patch clamp recordings demonstrated the presence of slow wave-like voltage oscillations driven by active current oscillations that match all properties seen in whole intestinal tissue slow waves. With different recording modes, whole cell currents, voltage and current oscillations were recorded from the same cell, showing that ICC are electrophysiologically unique and that the active inward current driving the slow wave-like oscillations are not voltage dependent. The isolated single ICC were demonstrated to have a specific tyrosine receptor marker protein for ICC, Kit , by selective RT-PCR amplification. The slow wave-like oscillations had a reversal potential consistent with a non-specific cation conductance. Although previous research had been done on single smooth muscle cells, there is currently no consensus on the cellular ionic currents present. In this thesis, analysis of different recordings demonstrated that there are at least four main groups of SMCs with different whole cell current profiles. Different cellular ionic currents were found specifically in different groups, and can be confirmed by reconstructing single channel recordings. One cellular outward current was chosen for further investigation-a fast activating and inactivating transient outward current. This current was characterized by common protocols and with a novel ramp analysis. Characterization revealed two distinct transient outward currents with different kinetic properties. Finally, spontaneous transient outward currents (STOCs) have been recorded in 25% of smooth muscle cells, reflecting quantal Ca2+ release from the intracellular stores to the plasmalemma calcium dependent potassium channels. Therefore, the study of STOCs gives direct information not only on the activities of intracellular Ca2+ stores, but also on the kinetics of Ca2+ release and reuptake in the microenvironment where STOCs originate. From these results, a simple model for GI motility was developed to account for the cellular interactions between nerve, ICC, and smooth muscle.Doctor of Philosophy (PhD
THE ROLE OF LUMINAL 5-HT4 RECEPTORS IN COLONIC MOTILITY
No full textFunctional gastrointestinal (GI) disorders including constipation and Irritable Bowel
Syndrome (IBS) constitute the most widespread digestive disorders that could involve GI
dysmotility and altered serotonin (5-HT) signaling. Current treatments include oral intake
of prokinetic drugs such as serotonin sub-type 4 receptor (5-HT4) agonists that activate 5-
HT4 receptors located on nerves in the gut wall. However, these receptors are also found
on the luminal side of enterochromaffin cells in the colonic epithelium where more than
90% of the body’s 5-HT is synthesized. Therefore, activation of luminal 5-HT4 receptors
by using a delivery system that releases the drug inside the colonic lumen without it being
first absorbed in the upper GI tract, can result in the release of 5-HT and increase in colonic
motility. This could significantly minimize the adverse side effects associated with
systemic absorption of such drugs. In this study, first the rabbit animal model was used to
test the effects of prucalopride after administration inside the colon (ex vivo). Results
showed significant increase in propulsive motor patterns and their properties such as
pressure and force. Such potent prokinetic effects occurred even in the presence of
simulated fecal impaction, an acute complication of chronic constipation. Using highresolution
colonic manometry (HRCM), all aspects of propulsive motility including the
colo-anal reflex and simultaneous pressure waves (SPW) were studied in vivo in healthy
volunteers; then, the effects of intraluminal prucalopride was evaluated with HRCM in a
human case study. Similar to the animal model, marked increase in propulsive motor
activity was observed. This project shows the SPW and the colo-anal reflex have potential
diagnostic values in patients with colonic dysmotility or abdominal bloating and
prucalopride incorporated in colon-specific drug delivery systems has the potential to
become the preferred prokinetic for the treatment of constipation. It also encourages further
research into the role of luminal 5-HT in generating normal colonic motor function.ThesisMaster of Science in Medical Sciences (MSMS
Electrical Communication Between Different Cell Types in the Colonic Musculature
No full textThe major cell types in the canine colon musculature are interstitial cells of Cajal (ICC), circular muscle (CM) cells and longitudinal muscle (LM) cells. In isolated muscle strip studies, spontaneous membrane potential oscillations (slow waves) are generated in the submucosal border of the circular muscle where a gap junctionally well-coupled network of ICC and CM is found. CM devoid of LM and submucosal pacemaker region (CM preparations) are spontaneously quiescent. The research undertaken was to understand the mechanism of slow wave propagation into the circular muscle and to investigate the consequences to the electrical activity in CM after coupling with different electrical activities from different cells types. Our results show that CM cells, although spontaneously quiescent because of high K+ conductance, are excitable and can actively participate in slow wave generation. The electrical oscillations induced in the CM preparations could easily be potentiated by an L-type Ca2+ channel activator, Bay K 8644, and abolished by a L-type Ca2+ antagonist, D600, suggesting involvement of the conductance in the induced activity. The induced oscillations are similar to the SLAPs in the longitudinal muscle which shows that it is not necessary to have a specialized pacemaker cells for generating SLAPs. Using a cross sectioned preparation with all intact muscle layers, we also showed that the heterogeneity in the electrical activity of CM, such as: the resting membrane potential gradient, depolarization of plateau potential in the myenteric border and "apparent" decay in slow wave amplitude, is due to electrical interactions between different intrinsic activities from different cell types. Morphological evidence was obtained for the possible communication pathways in the submucosal and the myenteric borders of the circular muscle. Different coupling mechanisms in different areas were hypothesized. In addition, the 3-dimensional aspects of the submucosal ICC network in the ca.nine colon were clarified.ThesisMaster of Engineering (ME
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