1,720,974 research outputs found
Validierung von Polyphosphat als wirksames Hämostyptikum im Vergleich zu kaolinbeschichteter QuickClot® Combat Gauze® bei arterieller Blutung am Schockmodell
No full textDer Verblutungstod ist eine aktuelle und lebensgefährliche Problematik in der militärischen Traumamedizin und der prä-klinischen zivilen Patientenversorgung. Hämostyptika, blutungsstillende Präparate, werden eingesetzt, um den Verblutungstod zu unterbinden. Dennoch gibt es kein Präparat, welches allen Kriterien eines idealen Hämostyptikums entspricht.
In dieser Arbeit wurde die Anwendbarkeit und Wirksamkeit von Polyphosphat (PolyP) und QuickClot® Combat Gauze® (QCCG), bei arterieller Blutung und Volumenmangelschock am lebenden Organismus miteinander verglichen. Ziel war es, durch die Anwendung von genannten Präparaten eine suffiziente Hämostase der arteriellen Blutung zu erreichen und so den post-interventionellen Blutverlust zu verringern. Die Durchführung der Versuche erfolgte als randomisierte experimentelle Studie am Großtiermodell mit Schweinen. Parameter der Hämodynamik und Respiration sowie BGA, Blutgerinnung und kleines Blutbild wurden kontinuierlich erhoben. Mittels Flussmesssonde wurde die Flussgeschwindigkeit in der linken Arteria femoralis zu jedem Zeitpunkt des Versuches abgeleitet. Mittels einer 3,6 mm Gefäßstanze wurde eine arterielle Blutung der A. femoralis sinistra erzeugt und durch einen Blutverlust von ca. 800g-1000 g, und daraus folgend einem MAP <60 mmHg ein Volumenmangelschock erzeugt. Anschließend erfolgte die Applikation des Hämostyptikums (PolyP/ QCCG) auf der Arterie und die fünf-minütige Kompression bei 200 mmHg. Nach der Blutstillung folgte die post-interventionelle Beobachtungsphase zur Beurteilung der Wirksamkeit der Hämostyptika, nach Blutdrucksteigerung durch Volumensubstitution, mit HAES 6 % oder durch Katecholamin Gabe. Zur Verifizierung des Schocks wurde die Mikrozirkulation von parenchymatösen Organen, präund post-interventionell, durch die Anwendung der Mikrosphären Methode dargestellt. Das in dieser Studie getestete PolyP erfüllt die Kriterien eines idealen Hämostyptikums, besonders durch seine bioresorbierbaren und biodegradierbaren Eigenschaften. Die gewonnenen Ergebnisse zeigen, dass bei Hämostyptika-Applikation eine permissive Hypotonie, mit einem systolischen Ziel-Blutdruck von 80 mmHg eine Reduktion der Mortalität bewirkt. Durch den verhältnismäßig niedrigen Blutdruck kann sich das Blutgerinnsel, welches zur Hämostase führt, besser stabilisieren, bis eine chirurgische Versorgung möglich ist. In Zukunft sollten weitere Studien zur Wirksamkeit von PolyP durchgeführt werden, um das Produkt noch weiter zu verbessern.Hemorrhage is a life-threatening problem in trauma medicine and pre-hospital civil patient care. Hemostatic dressings are used to stop severe bleeding and thus can prevent patients from bleeding to death. Nevertheless, there is no hemostatic dressing that fulfills all criteria of an ideal hemostat. In this work the effectiveness of two hemostats, polyphosphate (PolyP) and QuickClot® Combat Gauze® (QCCG), was tested on pigs. The test subjects were inflicted an arterial bleeding and a volume depletion shock. The aim of this randomized experimental study was to use PolyP and QCCG sufficiently to stop the arterial bleeding und thus minimize and prevent postinterventional blood loss.
27 German domestic pigs were used to conduct this trial. Hemodynamics, respiratory parameters as well as ABG, blood coagulation and small blood count were constantly monitored. Using the transit time flow measurement method, the blood flow velocity of the left femoral artery was measured continuously. An arterial hemorrhage of the left femoral artery was made, using a 3.6mm vascular punch. Due to the lesion of the vessel a volume deficiency shock with blood loss of approximately 800g-1000g, and an MAP <600mHg was caused. Afterwards the hemostatic dressings, either PolyPor QCCG, were applied to the lesion directly with a compression of 200mmHg for the following five minutes.
After the hemorrhage control the post-interventional follow up time of 120 minutes began. The aim was to assess the efficiency of the hemostat after increasing the blood pressure by volume substitution or catecholamines. To verify the shock, the microcirculation of parenchymal organs, pre- and post-interventional, was measured and analyzed using the fluorescence microsphere method. The PolyP fulfills the criteria of an ideal hemostat, especially because of its biodegradable and bioresorbable properties. The results of this study show that in addition to the hemostatic dressing itself permissive hypotension, with a systolic blood pressure of 80mmHg, plays an important role leading to the reduction of mortality. Due to the relatively low blood pressure, the formation of a stable blood clot is assured until surgical care is provided. Future studies should focus on the efficacy of PolyP, to improve the product
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Evaluation des Spidergrafts im Tiermodell an thorakoabdominellen Aortenpathologien mit besonderem Augenmerk auf die Blutversorgung des Rückenmarks
No full textVariations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Validierung der Fluoreszenzangiographie für die intraoperative Beurteilung und Quantifizierung der Myokardperfusion
Get PDFBACKGROUND: Intraoperative graft patency verification is of major clinical importance for quality control after coronary artery bypass grafting (CABG), especially if surgery is performed on the beating heart. This is one of the first reports of fluorescence coronary angiography (FCA) using the dye indocyanine green (ICG), a noninvasive technology for direct visualization of coronary arteries and myocardial perfusion.
METHODS: Twenty-five domestic pigs underwent FCA of the left anterior descending coronary artery (LAD). In the first group (n = 6 pigs), FCA was used to visualize the native coronary vessels and myocardial perfusion. In the second group (n = 8 pigs), 14 stenoses of various degrees and 4 total vessel occlusions were created by snares on different segments of the LAD, and FCA was used to visualize the effects of these obstructions. In the third group (n = 11 pigs) defined stenoses (25%; 50%, 75%, 100% flow reduction) on the distal part of the LAD were created by a custom-made screw occluder and determined using TTFM (transit-time-flow measurement). ICG was intravenously applied, and the heart was illuminated with near-infrared light emitted by laser diodes. The fluorescence emission was detected by an adapted charge-coupled device camera system. The images were displayed in real time on a high-resolution monitor. Subsequently, images obtained with FCA were correlated with fluorescent microspheres data (n = 11 pigs).
RESULTS: In all cases, high-quality FCA images of coronary arteries and myocardial perfusion were obtained. All stenoses resulted in an impairment of the myocardial perfusion visualized by FCA. Occlusion of the LAD or the diagonal branch resulted in a total perfusion defect of the corresponding anterior myocardial wall with immediate reperfusion after releasing the snare. Correlation between FCA and fluorescent microspheres in determination of myocardial perfusion was excellent.
CONCLUSION: With the fluorescence technique using ICG, visualization of blood flow in coronary vessels and myocardial perfusion, is feasible. FCA is a highly sensitive and reproducible method and an excellent technique for intraoperative quality control in CABG
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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