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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

New Therapeutic Approaches in Pulmonary Embolism

Schellong, Sebastian M., Schmidt, Benjamin A. 12 February 2014 (has links) (PDF)
Pulmonary embolism as a part of venous thromboembolic disease has a broad spectrum of clinical presentations from minimal disease to life-threatening right heart failure. Therapy has to be guided by the risk associated with the individual clinical state of the patient. As long as hemodynamics are entirely stable, anticoagulation is given in order to prevent early or late recurrence, thereby allowing for endogeneous thrombolysis and recovery. In hemodynamically instable patients, i.e. patients under cardiopulmonary resuscitation or in shock, there is the need for a rapid reduction of thrombus mass in order to restore right ventricular function. Systemic thrombolysis is the most feasible modality to reduce the thrombus burden of the pulmonary circulation in the short term. For hemodynamically stable patients with right ventricular dysfunction as assessed by echocardiography, there is still some controversy as to whether thrombolysis improves the long-term outcome. At the least, thrombolysis may positively modify the short-term course of acute disease in patients with an extremely low risk of bleeding. When the acute phase has been overcome, secondary prophylaxis with vitamin K antagonists has to be given. The duration of secondary prophylaxis requires an individual assessment of both the risk of recurrence and the risk of bleeding. In the near future, new anticoagulant drugs such as direct thrombin and factor Xa inhibitors will offer new treatment modalities for the acute phase as well as for secondary prophylaxis. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
2

New Therapeutic Approaches in Pulmonary Embolism

Schellong, Sebastian M., Schmidt, Benjamin A. January 2003 (has links)
Pulmonary embolism as a part of venous thromboembolic disease has a broad spectrum of clinical presentations from minimal disease to life-threatening right heart failure. Therapy has to be guided by the risk associated with the individual clinical state of the patient. As long as hemodynamics are entirely stable, anticoagulation is given in order to prevent early or late recurrence, thereby allowing for endogeneous thrombolysis and recovery. In hemodynamically instable patients, i.e. patients under cardiopulmonary resuscitation or in shock, there is the need for a rapid reduction of thrombus mass in order to restore right ventricular function. Systemic thrombolysis is the most feasible modality to reduce the thrombus burden of the pulmonary circulation in the short term. For hemodynamically stable patients with right ventricular dysfunction as assessed by echocardiography, there is still some controversy as to whether thrombolysis improves the long-term outcome. At the least, thrombolysis may positively modify the short-term course of acute disease in patients with an extremely low risk of bleeding. When the acute phase has been overcome, secondary prophylaxis with vitamin K antagonists has to be given. The duration of secondary prophylaxis requires an individual assessment of both the risk of recurrence and the risk of bleeding. In the near future, new anticoagulant drugs such as direct thrombin and factor Xa inhibitors will offer new treatment modalities for the acute phase as well as for secondary prophylaxis. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
3

Gerinnungsdiagnostik bei Patienten vor und nach Implantation eines linksventrikulären Herzunterstützungssystems

Klaeske, Kristin 07 November 2024 (has links)
Linksventrikuläre Herzunterstützungssysteme (LVAD) sind eine wichtige Behandlungsoption für Patienten mit chronischer Herzinsuffizienz. Trotz einer progressiven Verbesserung der Lebensqualität und erhöhten Überlebensrate von LVAD-Patienten gehören nicht-chirurgisch bedingte Blutungen (NSB) wie gastrointestinale Blutungen immer noch zu den bedeutendsten LVAD-assoziierten Komplikationen. Die genaue Pathogenese der NSB ist jedoch bisher unzureichend bekannt und daher ein wichtiger Schwerpunkt der gegenwärtigen Forschung. Ein Vergleich der Ausprägung des erworbenen von Willebrand Syndroms (aVWS) bei Patienten mit HM 3™ und HVAD™ ist daher für das LVAD-Management von großem Interesse. Daher haben wir eine retrospektive Beobachtungsstudie durchgeführt, um die vWF Multimerstruktur sowie die damit verbundenen funktionellen Parameter bei Patienten mit implantierten HM 3™ und HVAD™ zu vergleichen. Unsere Ergebnisse zeigten einen geringeren Verlust der HMWMs des vWF, eine erhöhte vWF-Aktivität und Faktor-VIII-Plasmakonzentration bei HM 3™-Patienten im Vergleich zu Patienten mit HVAD™. Der verringerte Verlust der HMWMs nach HM 3™-Implantation könnte auf eine Reduktion des nicht-physiologischen Scherstresses (NPSS) zwischen dem vWF und den rotierenden Elementen der Pumpe zurückzuführen sein. Die daraus resultierende stabilere vWF Multimerstruktur könnte die Hämokompatibilität verbessern und damit die Komplikationsrate von LVAD-Patienten verringern. Der durch das LVAD induzierte NPSS hat nicht nur Auswirkungen auf die vWF Multimerstruktur, sondern auch auf die Aktivierung von Thrombozyten während der primären Hämostase. Um die durch NPSS-verursachten zellulären Veränderungen der Thrombozyten und deren Funktion zu untersuchen, wurde die Oberflächenexpression verschiedener Thrombozytenrezeptoren und der oxidative Stress mittels thrombozytärer ROS-Konzentration bei LVAD-Patienten mit und ohne Blutungskomplikationen untersucht. Die Ergebnisse zeigten eine verringerte Oberflächenexpression der Thrombozytenrezeptoren P-Selektin, GPIbα und PECAM-1 sowie erhöhten oxidativen Stress bei LVAD-Patienten mit NSB, unabhängig vom Zeitpunkt des Auftretens der Blutung. Wir vermuten, dass der Verlust des vWF-Rezeptors GPIbα und die gestörte Sekretion der P-Selektin- und PECAM-1-enthaltenden α-Granula die Thrombusbildung beeinträchtigen könnten und damit die Blutungsneigung der LVAD Patienten erhöhen. Trotz des ubiquitären LVAD-induzierten NPSS scheinen nicht alle Patienten dasselbe Risiko für NSB zu haben. Wir vermuten daher, dass sich Patienten mit zukünftigen Blutungskomplikationen bereits vor LVAD-Implantation von Patienten ohne NSB unterscheiden. Alle erfassten klinischen Parameter sowie die Oberflächenexpression der Thrombozytenrezeptoren wurde bei Patienten vor LVAD-Implantation und zum Zeitpunkt des ersten Auftretens einer Blutungskomplikation innerhalb eines Jahres nach LVAD-Implantation miteinander verglichen. Unsere Ergebnisse zeigten, dass Patienten mit zukünftigen Blutungskomplikationen bereits vor LVAD-Implantation eine reduzierte Oberflächenexpression der Thrombozytenrezeptoren P-Selektin und GPIIb/IIIa aufweisen. Die verringerte Expression von P Selektin und GPIIb/IIIa könnte die Adhäsions- und Aggregationsfähigkeit der Thrombozyten einschränken und damit die Blutungsneigung dieser Patienten erhöhen. Die frühzeitige kombinierte Messung klinischer Marker und die Überprüfung einer potenziellen Thrombozytenfunktionsstörung, die anhand der Oberflächenexpression von Thrombozytenrezeptoren nachgewiesen wurde, könnte zu einer verbesserten Bewertung des individuellen Blutungsrisikos bei Patienten, die für eine LVAD-Implantation evaluiert werden, beitragen.
4

Decolorization of reactive dyeing wastewater by Poly Aluminium Chloride / Nghiên cứu khử màu nước thải nhuộm hoạt tính bằng Poly Aluminium Chloride

Perng, Yuan-Shing, Bui, Ha-Manh 19 August 2015 (has links) (PDF)
Color removal of some reactive dyes (Blue 19, Black 5 and Red 195) using a local Poly Aluminium Chloride (PAC) was investigated with Jar-test experiment. The dyes were removed (above 94%) at optimal pH 7 (Red 195) and pH 10 (Blue 19 and Black 5). The PAC dosage of 220 mg/L (Blue 19 and Black 5) and 160 mg/L (Red 195) were found to be best for decreasing dye up to 50 mg/L (Black 5, Red 195) and 100 mg/L (Blue 19). Reaction time and agit ation speed also affected the decolorization process. That result indicates that Vietnamese PAC can be a robust and economical coagulant for discolorization of reactive dyeing process. / Chất keo tụ Poly Aluminium Chloride (PAC) sản xuất tại Việt nam được ứng dụng khử màu của một số màu nhuộm hoạt tính phổ biến (Blue 19, Black 5 and Red 195) trên thí nghiệm Jar-test. Kết quả cho thấy màu bị loại gần như hoàn toàn (trên 94 %) tại pH 7 (Red 195) hoặc 10 (Blue 19 và Black 5). Nồng độ PAC đạt hiệu quả tốt nhất tại 220 mg/L (Blue 19 và Black 5) và 160 mg/L (Red 195) ứng với nồng độ màu 50 mg/L (Black 5, Red 195) hay 100 mg/L (Blue 19). Thời gian phản ứng, tốc độ khuấy cũng có tác động đến hiệu suất khử màu. Kết quả nghiên cứu cho thấy PAC sản xuất tại Việt nam không những là một chất keo tụ tốt mà còn rất kinh tế cho việc khử màu hoàn toàn trong nước thải nhuộm hoạt tính.
5

Decolorization of reactive dyeing wastewater by ferrous ammonium sulfate hexahydrate / Nghiên cứu khử màu nước thải nhuộm hoạt tính bằng muối sắt II

Perng, Yuan-Shing, Bui, Ha-Manh 19 August 2015 (has links) (PDF)
This paper presents the result of dyeing solution coagulation with the use of ferrous ammonium sulfate hexah ydrate (FAS). The examined solution contains two reactive dyes: Black 5 and Blue 19. It has been shown that the efficiency of the dye removal depends on the type of dye, coagulation dosage and the initial pH. Our result showed that the increase of initial pH up to 12 enhanced the color removal efficiency; the FAS dose was 280 ml (Black 5) and 180 mg/l (Blue 19) at slow mixing time (15 min), agitation speed 60 rpm, and the initial dye concentration should be 50 and 100 mg/L for Black 5 and Blue 19, respectively. / Chất keo tụ sắt (II) amoni sulfate (FAS) được sử dụng khử màu của hai màu nhuộm hoạt tính phổbiến (Blue 19 và Black 5). Kết quả cho thấy, quá trình keo tụ bịảnh hưởng nhiều bởi loại màu nhuộm, nồng độ chất keo tụ và pH của dung dịch đầu vào. Với nồng độ FAS 280 mg/l (Black 5) và 180 mg/l (Blue 19), pH đầu vào dung dịch khoảng 12, thời gian phản ứng 15 phút, tốc độ khuấy 60 vòng/phút ứng với nồng độ màu Black 50 mg/L và blue 100 mg/L dung dịch gần như mất màu hoàn toàn.
6

Decolorization of reactive dyeing wastewater by Poly Aluminium Chloride: Research article

Perng, Yuan-Shing, Bui, Ha-Manh 19 August 2015 (has links)
Color removal of some reactive dyes (Blue 19, Black 5 and Red 195) using a local Poly Aluminium Chloride (PAC) was investigated with Jar-test experiment. The dyes were removed (above 94%) at optimal pH 7 (Red 195) and pH 10 (Blue 19 and Black 5). The PAC dosage of 220 mg/L (Blue 19 and Black 5) and 160 mg/L (Red 195) were found to be best for decreasing dye up to 50 mg/L (Black 5, Red 195) and 100 mg/L (Blue 19). Reaction time and agit ation speed also affected the decolorization process. That result indicates that Vietnamese PAC can be a robust and economical coagulant for discolorization of reactive dyeing process. / Chất keo tụ Poly Aluminium Chloride (PAC) sản xuất tại Việt nam được ứng dụng khử màu của một số màu nhuộm hoạt tính phổ biến (Blue 19, Black 5 and Red 195) trên thí nghiệm Jar-test. Kết quả cho thấy màu bị loại gần như hoàn toàn (trên 94 %) tại pH 7 (Red 195) hoặc 10 (Blue 19 và Black 5). Nồng độ PAC đạt hiệu quả tốt nhất tại 220 mg/L (Blue 19 và Black 5) và 160 mg/L (Red 195) ứng với nồng độ màu 50 mg/L (Black 5, Red 195) hay 100 mg/L (Blue 19). Thời gian phản ứng, tốc độ khuấy cũng có tác động đến hiệu suất khử màu. Kết quả nghiên cứu cho thấy PAC sản xuất tại Việt nam không những là một chất keo tụ tốt mà còn rất kinh tế cho việc khử màu hoàn toàn trong nước thải nhuộm hoạt tính.
7

Decolorization of reactive dyeing wastewater by ferrous ammonium sulfate hexahydrate: Research article

Perng, Yuan-Shing, Bui, Ha-Manh 19 August 2015 (has links)
This paper presents the result of dyeing solution coagulation with the use of ferrous ammonium sulfate hexah ydrate (FAS). The examined solution contains two reactive dyes: Black 5 and Blue 19. It has been shown that the efficiency of the dye removal depends on the type of dye, coagulation dosage and the initial pH. Our result showed that the increase of initial pH up to 12 enhanced the color removal efficiency; the FAS dose was 280 ml (Black 5) and 180 mg/l (Blue 19) at slow mixing time (15 min), agitation speed 60 rpm, and the initial dye concentration should be 50 and 100 mg/L for Black 5 and Blue 19, respectively. / Chất keo tụ sắt (II) amoni sulfate (FAS) được sử dụng khử màu của hai màu nhuộm hoạt tính phổbiến (Blue 19 và Black 5). Kết quả cho thấy, quá trình keo tụ bịảnh hưởng nhiều bởi loại màu nhuộm, nồng độ chất keo tụ và pH của dung dịch đầu vào. Với nồng độ FAS 280 mg/l (Black 5) và 180 mg/l (Blue 19), pH đầu vào dung dịch khoảng 12, thời gian phản ứng 15 phút, tốc độ khuấy 60 vòng/phút ứng với nồng độ màu Black 50 mg/L và blue 100 mg/L dung dịch gần như mất màu hoàn toàn.
8

Effectiveness on color and COD of textile wastewater removing by biological material obtained from Cassia fistula seed

Trung, Dao Minh, Tuyen, Nguyen Thi Khanh, Anh, Le Hung, Ngan, Nguyen Vo Chau 14 December 2018 (has links)
Nowadays, natural polymeric materials extracted from plants are the new alternatives for synthetic chemicals in water and wastewater treatment. The aim of this study is to evaluate the ability of Cassia fistula seed gum (CFG) as a coagulant aid with PAC in the treatment of textile wastewater. Jartest experiments were carried out to identify the optimal parameters of coagulation-flocculation for removing color and COD in synthesis wastewater containing Methyl blue and RB21 dyes, including pH, settling time, PAC dose, the optimal CFG dosage in comparing with the cationic polymer. After that, actual textile wastewater was treated by using PAC, PAC plus cationic polymer, and PAC plus CFG for evaluating the role of CFG. CFG supplementation has assisted the process effects at nearly 98% color, 85% COD for RB21 and 90% color, 70% COD for MB at the best dose of CFG 0.15 mL and 0.1 mL, respectively. The optimized parameters for the coagulation of real textile wastewater using PAC were pH = 6 and dose = 0.6 mL can removal 66% of color. By adding CFG to PAC, the efficient of treatment was increased about 70% even at the lower dosage of PAC and CFG (0.5 mL for each reagent). The yield of combining PAC and polymer was a little bit lower than PAC and CFG, for instant 68% color was decreased at the same condition. These achievements demonstrated a workable substitute of natural products such as Cassis fistula seed gum for synthetic chemical products in coagulation-flocculation process. / Hiện nay các loại vật liệu sinh học chiết xuất từ thực vật đang được nghiên cứu ứng dụng trong xử lý nước và nước thải thay cho các chất hóa học. Mục tiêu của nghiên cứu này là đánh giá hiệu quả của việc sử dụng gum được chiết xuất từ hạt cây Muồng Hoàng Yến (MHY) làm chất trợ keo tụ trong xử lý nước thải dệt nhuộm. Thí nghiệm Jartest được tiến hành nhằm xác định các điều kiện tối ưu cho quá trình xử lý nước thải tổng hợp chứa thuốc nhuộm Methyle Blue (MB) và RB21 bao gồm pH, thời gian lắng, liều PAC, liều gum MHY và liều polymer. Sau đó tiến hành xử lý nước thải thật với các điều kiện thích hợp đã xác định nhằm đánh giá vai trò của gum MHY. Gum MHY làm tăng hiệu quả của quá trình xử lý, đạt gần 98% đối với độ màu, 85% COD đối với RB21, 90% độ màu và 70% COD đối với MB với liều lượng tương ứng là 0,15 mL và 0,1 mL. Các thông số tối ưu cho quá trình xử lý trên mẫu nước thải thật là pH = 6, liều PAC = 0.6 mL có thể làm giảm 66% độ màu. Bổ sung gum MHY làm chất trợ keo tụ giúp gia tăng hiệu quả xử lý màu lên 70% dù với liều lượng rất thấp là 0,5 mL. Hiệu suất xử lý khi sử dụng kết hợp PAC và polymer thấp hơn trong trường hợp sử dụng PAC và gum MHY, cụ thể khoảng 68% độ màu được xử lý ở cùng một điều kiện. Những kết quả này cho thấy tiềm năng của việc sử dụng các vật liệu gum tự nhiên nhằm thay thế cho các hợp chất hóa học trong các quá trình keo tụ tạo bông để xử lý nước thải.
9

Enhancing Anticoagulation Monitoring and Therapy in Patients Undergoing Microvascular Reconstruction in Maxillofacial Surgery: A Prospective Observational Trial

Schröder, Tom A., Leonhardt, Henry, Haim, Dominik, Bräuer, Christian, Papadopoulos, Kiriaki K., Vicent, Oliver, Güldner, Andreas, Mirus, Martin, Schmidt, Jürgen, Held, Hanns C., Birkner, Thomas, Beyer-Westendorf, Jan, Lauer, Günter, Spieth, Peter M., Koch, Thea, Heubner, Lars 04 June 2024 (has links)
Background: In reconstructive surgery, loss of a microvascular free flap due to perfusion disorders, especially thrombosis, is a serious complication. In recent years, viscoelastic testing (VET) has become increasingly important in point-of-care (POC) anticoagulation monitoring. This paper describes a protocol for enhanced anticoagulation monitoring during maxillofacial flap surgery. Objective: The aim of the study will be to evaluate, in a controlled setting, the predictive value of POC devices for the type of flap perfusion disorders due to thrombosis or bleeding. VET, Platelet monitoring (PM) and standard laboratory tests (SLT) are comparatively examined. Methods/Design: This study is an investigator-initiated prospective trial in 100 patients undergoing maxillofacial surgery. Patients who undergo reconstructive surgery using microvascular-free flaps will be consecutively enrolled in the study. All patients provide blood samples for VET, PM and SLT at defined time points. The primary outcome is defined as free flap loss during the hospital stay. Statistical analyses will be performed using t-tests, including the Bonferroni adjustment for multiple comparisons. Discussion: This study will help clarify whether VET can improve individualized patient care in reconstruction surgery. A better understanding of coagulation in relation to flap perfusion disorders may allow real-time adaption of antithrombotic strategies and potentially prevent flap complications.
10

Hemocompatibility tuning of an innovative glutaraldehyde-free preparation strategy using riboflavin/UV crosslinking and electron irradiation of bovine pericardium for cardiac substitutes

Dittfeld, Claudia, Welzel, Cindy, König, Ulla, Jannasch, Anett, Alexiou, Konstantin, Blum, Ekaterina, Bronder, Saskia, Sperling, Claudia, Maitz, Manfred F., Tugtekin, Sems-Malte 07 June 2024 (has links)
Hemocompatibility tuning was adopted to explore and refine an innovative, GA-free preparation strategy combining decellularization, riboflavin/UV crosslinking, and low-energy electron irradiation (SULEEI) procedure. A SULEEI-protocol was established to avoid GA-dependent deterioration that results in insufficient long-term aortic valve bioprosthesis durability. Final SULEEI-pericardium, intermediate steps and GA-fixed reference pericardium were exposed in vitro to fresh human whole blood to elucidate effects of preparation parameters on coagulation and inflammation activation and tissue histology. The riboflavin/UV crosslinking step showed to be less efficient in inactivating extracellular matrix (ECM) protein activity than the GA fixation, leading to tissue-factor mediated blood clotting. Intensifying the riboflavin/UV crosslinking with elevated riboflavin concentration and dextran caused an enhanced activation of the complement system. Yet activation processes induced by the previous protocol steps were quenched with the final electron beam treatment step. An optimized SULEEI protocol was developed using an intense and extended, trypsin-containing decellularization step to inactivate tissue factor and a dextran-free, low riboflavin, high UV crosslinking step. The innovative and improved GA-free SULEEI-preparation protocol results in low coagulant and low inflammatory bovine pericardium for surgical application.

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