1,720,972 research outputs found
High thoracic anesthesia influence in the early postoperative period from patients, who had coronary artery bypass graft surgery (CABGS) with cardiopulmonary bypass (CPB)
No full textAuthor: Rokas Imbrasas Title: High thoracic anesthesia influence in the early postoperative period from patients, who had coronary artery bypass graft surgery (CABGS) with cardiopulmonary bypass (CPB) Aims of the study: Check HTEA influence for the blood loss in the early postoperative period from patients, who had coronary artery bypass graft surgery (CABGS) with cardiopulmonary bypass (CPB). Objectives of the study: 1. Evaluate the influence of HTEA to Hematocrit and Hemoglobin concentration in the early postoperative period of patients, who had coronary artery bypass graft surgery (CABGS) with cardiopulmonary bypass (CPB). 2. Evaluate the influence of HTEA to blood loss in the early postoperative period of patients, who had coronary artery bypass graft surgery (CABGS) with cardiopulmonary bypass (CPB). 3. Evaluate the influence of HTEA to blood components usage in the early postoperative period of patients, who had coronary artery bypass graft surgery (CABGS) with cardiopulmonary bypass (CPB). Participants of the study: The study included patients (from 49 to 82 years), who had received CABGS with CPB at Lithuania university of health sciences Clinic of Cardiothoracic and vascular surgery. Methods: All patients were divided into two groups: first group (GA), which included patients who had received only GA (anesthetics and intravenous opiates); and second group (HTEA) which included patients who received HTEA (local anesthetic and GA anesthetics with intravenous opiates). Biochemical blood tests were run three times on each patient - before the surgery, 6h after surgery and 12h after surgery. The concentrations of hemoglobin and hematocrit, blood loss were measured and compared. Results of the study: The levels of hematocrit and hemoglobin during operation and early period after operation had no statistical significant difference. ACT had also no significant difference before CPB: HTEA 127, 7 ± 17,7 GA 129,9 ± 14,7 and in intensive care unit: HTEA 128 ± 16,9 GA 137,7 ± 19,4. The probability of using blood components was the same in both groups HTEA 6 times and GA 6 times. There was 100ml difference in blood loss after 12h post operation, but not statistically significant. Blood loss during operation: HTEA 486.7±130.6 GA 488.3±173 6h after operation HTEA 746.7±220.4 GA 752.5±186 12h after operation HTEA 1020.7±217.4 GA 910.8±213.3. Blood loss during operation and 6h after had no difference. Conclusion: 1.Hematocrit and hemoglobin levels had no statistically significant difference. 2. Blood loss during operation had no statistically significant difference. 3. HTEA had no influence for blood components usage
The Impact of Choice of Cardioplegia on Early Postoperative Arrhythmias Following On Pump Coronary Artery Bypass Grafting Surgery
No full textAim of the study: To evaluate the impact of cardioplegia on early postoperative arrhythmias in patients undergoing on pump coronary artery bypass grafting surgery. Objectives of the study: 1) To compare the recovery of normal heart rhythm in post ischaemic period when blood or crystalloid cardioplegia is used; 2) To compare the changes in blood potassium concentration in post ischaemic period, according to choice of cardioplegia; 3) To compare the frequency of early postoperative arrhythmias when blood or crystalloid cardioplegia is used; Participants of the study: Patients undergoing on pump coronary artery bypass grafting surgery with blood or crystalloid cardioplegia were included in the study. The inclusion criteria were: only coronary artery bypass grafting surgery performed; patient age 18 - 80 years; good left ventricular function (EF ≥ 45% according to Simpson). Patients undergoing complex surgeries or those with diagnosed aortic valve insufficiency (more than I) were excluded. Methods: 203 patient charts were analysed, and divided to groups according to type of cardioprotective solution. Group A received cold St. Thomas crystalloid cardioplegic solution (n = 169), group B received warm blood cardioplegia (n = 34). Recovery of normal heart rhythm and blood potassium concentration changes in post ischaemic period were assesed. Early postoperative period arrhythmias were considered. Results of the study: according to perioperative data, no significant difference between two groups was found (p ˃ 0,05). 81,28% of patients were in sinus rhythm after unclamping the aorta, and 17,7% of patients had arrhythmias. According to the choice of cardioplegia, sinus rhythm was significantly more frequent when blood cardioplegia was used (p = 0,012). No statistically significant difference in blood potassium concentrations was found before bypass (p > 0,05). Blood potassium concentrations before and after unclamping the aorta was significantly higher in blood cardioplegia group (p 0,05). Postoperative atrial fibrillation occurred more often in crystalloid cardioplegia group after more than 24 hours after surgery (p = 0,05)
Influence of thoracic epidural anesthesia to extravascular lung water, haemodynamic changes and postoperative time during on-pump cardiac surgery
No full textThoracic epidural anaesthesia, directly influencing blood circulation in a small circle of blood circulation, definitely has impact on amount of a liquid in a lung interstitial tissue (amount of extravascular lung water). Increase of extravascular lung water level deteriorates function of lungs. Unfortunately, there is still data unavailable analysing influence of thoracic epidural anaesthesia on amount of extravascular lung water. This is one of the first studies analysing this issue.Aim of the study – to determine impact of thoracic epidural anaesthesia applied during on-pump human cardiosurgery on amount of extravascular lung water, cardiovascular system and course of a post-operative period. Sixty patients undergoing coronary artery bypass graft surgery were enrolled in the study. They were randomized into two groups: control group patients received general anaesthesia (GA, n = 30) and patients in epidural anaesthesia group (TEA, n = 30) underwent general anaesthesia with TEA. Conclusion: Thoracic epidural anaesthesia during on-pump cardiac surgery has shown insignificant changes of extravascular lung water index during entire surgery and early post-operative period. Thoracic epidural anaesthesia during on-pump cardiac surgery significantly increases cardiac index (p < 0.01) after cardiopulmonary bypass and significantly increases systolic index (p < 0.001) during entire surgery and early post-operative period
Research and creation of a semi-active damper-energy harvester system
No full textDisertacijoje nagrinėjama virpesių valdymo problema esant stochastiniams virpesiams. Pagrindinis tyrimo objektas – virpesių slopintuvas, kurio slopinimo valdymas grindžiamas magnetinio slopinimo ir energijos generavimo iš virpesių į elektros energiją. Disertacijos tikslas – sukurti virpesių slopintuvą su magnetinio slopinimo galimybe ir ištirti virpesių energijos generavimo bei virpesių valdymo galimybes.
Darbe sprendžiami keli uždaviniai: pasiūloma virpesių energijos generavimo į elektros energiją metodika tiesiniam slopintuvui ir nustatoma galimybė naudoti šį procesą virpesių slopinimui valdyti. Pirmasis uždavinys suformuluotas, nes, atlikus literatūros apžvalgą, nustatyta, jog virpesių energija nepanaudojama, nors jos kiekis yra svarbus šiuolaikinių sistemų maitinimui ir lengvai integruojamas į bendras prietaisų maitinimo sistemas. Antrasis siejasi su pirmuoju, nes virpesių slopinimo valdymas sunkiai įgyvendinamas ir reikalauja papildomos išorinės
energijos, tad šie du procesai galėtų būti sujungti.
Disertaciją sudaro įvadas, trys skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai.
Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas ir uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai. Įvado pabaigoje pristatomos disertacijos tema autoriaus paskelbtos publikacijos ir pranešimai konferencijose bei disertacijos struktūra.
Pirmasis skyrius skirtas literatūros apžvalgai. Jame pateikiama virpesių slopintuvų konstrukcijų, virpesių valdymo principai ir techninis realizavimas bei virpesių energijos generatorių apžvalga. Skyriaus pabaigoje formuluojamos išvados ir tikslinami disertacijos uždaviniai.
Antrajame skyriuje pateiktas viso automobilio dinaminis modelis, kuriame yra virpesių slopintuvas. Skyriuje taip pat pateikti magnetinio lauko simuliacijos modelis, kurio rezultatai leido suformuoti mechatroninio įrenginio modelio struktūrą ir pagaminti įrenginį.
Trečiajame skyriuje aprašyti virpesių slopintuvo eksperimentiniai tyrimai. Nurodoma naudojama įranga, eksperimentų metodika ir pateikti rezultatai, kurie leidžia įvertinti tiriamosios problemos sprendimo galimybes.
Disertacijos tema yra atspausdinti šeši moksliniai straipsniai, trys – mokslo žurnaluose, įtrauktuose į Clarivate Analysis Web of Science duomenų bazę su citavimo rodikliu sąrašą; trys – mokslo žurnaluose, įtrauktuose į kitas tarptautines duomenų bazes. Disertacijoje atliktų tyrimų rezultatai buvo paskelbti dviejose konferencijose užsienyje.Daktaro disertacij
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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