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Treatment of [1,4-(PhS)2C6H4] and [1,2-(PhS)2C6H4] with the appropriate amount of O-mesitylenesulfonylhydroxylamine (MSH) yields the corresponding protonated sulfimides, both of which may be deprotonated with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to give the hydrated free sulfimides [1,4-(PhS{NH2})2C6H4] and [1,2-(PhS{NH2})C6H4PhS]. It would seem that both products display the ability to give two distinct types of material, anhydrous and hydrated forms. The hydrated type [1,4-(PhS{NH2})2C6H4].2H2O has been found by crystallography to form an extended array system; whereas the crystal structure of the dehydrate exhibits extra structural "rigidity" brought about by having two hydrogen-bonded sulfimide units per molecule. The ligand [1,2-(PhS{NH2})C6H4PhS] also exhibits two distinct types of formation, one a dehydrate (exhibited as an oil) and the other a hydrated type (present as a crystalline solid).

Die Anzahl von Patienten mit einer dauerhaften oralen Antikoagulation sowie einer elektiven Operation steigt kontinuierlich. Meist erfolgt die perioperative Umstellung auf ein niedermolekulares Heparin, das sogenannte Bridging. Bisher gibt es keine evidenzbasierte Leitlinie. In der aktuellen Literatur zeigt sich, dass das perioperative Bridging das Risiko einer postoperativen Blutung erhöht. Ziel der Studie war es, das Blutungsrisiko beim Bridging und die Leitlinienadhärenz bei viszeralchirurgischen Eingriffen zu untersuchen. Es handelt sich um eine retrospektive, monozentrische Studie. Die Patientenselektion erfolgte mit dem Krankenhausinformationssystem für den Zeitraum 01. Januar 2011 bis 31. Dezember 2014. Eingeschlossen wurden Patienten mit einer dauerhaften oralen Antikoagulation, verfügbaren Patientenakte und einem elektiven operativen Eingriff. Ausschlusskriterien waren Notfalleingriffe, bariatrische Eingriffe und Gefäßoperationen. Erfasst wurden Komorbiditäten, die perioperative Dosierung und Pausierung des Bridging sowie postoperative Komplikationen. Insgesamt konnten 263 Fälle ausgewertet werden, wobei in 58 Fällen postoperative Blutungen auftraten (22,1%; 30 subkutane Hämatome, 17 lokale Blutungen, 5 Hämaskos, 3 peranale Blutungen, 3 Sonstige), in 68 Fällen erfolgten Transfusionen (26%) und in 40 Fällen Revisionsoperationen (15%). Das Risiko für Blutungen war erhöht beim Bridging in einer therapeutischen Dosierung (2x1mg/kgEnoxaparin;N=51/189,27%) im Vergleich zur halb- therapeutischen (1x1mg/kg; N=3/26, 12%) und prophylaktischen Dosierung (1x40mg; N=4/49, 8%; P=0,007). Thromboembolische Ereignisse traten bei 2 Patienten auf (0,8%; Apoplex, Lungenembolie). Eine falsche Risikobewertung führte bei 28 Patienten (11%) zu einem nicht indizierten therapeutischen Bridging, wobei hier 7 Blutungen auftraten. Darüber hinaus war die perioperative Pausierung des Bridging bei der Mehrzahl der Fälle zu kurz. Die präoperative Pausierung korrelierte mit dem Risiko für Bluttransfusionen (P=0,028). Die Leitlinie wurde bei 96% der Patienten nicht befolgt. Patienten mit einem Bridging in einer therapeutischen Dosierung unterliegen einem hohen Risiko für postoperative schwere Blutungskomplikationen. In der Praxis wird die Indikation zum Bridging oftmals nicht ausreichend differenziert und die perioperative Pausierung nicht eingehalten. Die Indikation zum perioperativen Bridging muss mit Hilfe einer individuellen präoperativen Risikostratifizierung für das perioperative Blutungs- und Thromboembolierisiko gestellt werden. / Increasing numbers of patients receiving oral anticoagulants are undergoing elective surgery. Bridging therapy is commonly thought to reduce the risk of postoperative bleeding and thromboembolic events. Low molecular weight heparin (LMWH) is frequently applied as bridging therapy during perioperative interruption of anticoagulation. The aim of this study was to explore the postoperative risk of bleeding and thromboembolic complications of patients receiving surgery under bridging anticoagulation. We performed a monocentric retrospective study over the period 2011-2014 using the clinical data system. Inclusion criteria were elective surgery, oral anticoagulation and full available patient records. Exclusion criteria emergency surgery, bariatric surgery and vascular surgery. Acquired data were comorbidity, perioperative enoxaparin dosage and pause., postoperative bleeding and thromboembolic events. The statistical analysis was performed with IBM SPSS Statistics 22. The sample of the study consisted of 263 patients. Postoperative overall bleeding events occurred in 58 patients (22,1%), postoperative need of blood cell transfusion in 68 patients (26%) and revision surgery in 40 patients (15%). Patients undergoing bridging in full therapeutic dosage enoxaparin (2x1mg/kg; n=51/189, 27%) had a higher risk for postoperative bleeding compared to half therapeutic dosage (1x1mg/kg; n=3/26, 12%) and prophylactic dosages of enoxaparin (1x40mg/kg; n=4/49, 8%; P=0,007). Thromboembolic events occurred only in two patients (0,8%; Stroke, Pulmonary Embolism). Bridging by clinical protocol (n=11/263; 4%) led to an overall bleeding risk of 45,5% (n=5/11), whereas not following protocol (n=252/263; 96%) resulted in 21% (n=53/252; P=0,056). Perioperative bridging anticoagulation, especially full-therapeutic dose LMWH, markedly increases the risk of postoperative bleeding complications in general and visceral surgery. Surgeons should carefully consider the practice of routine bridging.

Ziel der Studie war es, das postoperative Blutungsrisiko von Patienten im Rahmen einer elektiven Operation zu untersuchen die aufgrund einer oralen Antikoagulation die überbrückende Therapie (Bridging) mit niedermolekularem Heparin erhielten. Eine monozentrische, retrospektive Fall-Kontrollstudie (n = 526 Patienten) wurde durchgeführt, um die Inzidenz schwerer und leichter postoperativer Blutungen sowie thromboembolischer Ereignisse, die Verweildauer und die Mortalität im Krankenhaus zu ermitteln. In den Ergebnissen konnte eine erhöhte postoperative Inzidenz von schweren (8% vs. 1%; p <0,001) und leichten (14% vs. 5%; p <0,001) Blutungsereignissen festgestellt werden. Thromboembolische Ereignisse waren in beiden Gruppen selten (1% vs. 2%; p = 0,45). Es kam zu keiner erhöhten Mortalität (1,5% vs. 1,9%). Als unabhängige Risikofaktoren für schwere postoperative Blutungen konnten die volle therapeutische Dosis von LMWH, Niereninsuffizienz und das eingriffsspezifische Blutungsrisiko bestimmt werden. Unter Berücksichtigung der Ergebnisse dieser Studie sollte die routinemäßige Bridgingtherapie in der allgemeinen und viszeralen Chirurgie sorgfältig abgewogen werden. / The aim of the study was to investigate the postoperative bleeding risk of patients undergoing elective surgery when low molecular heparin was applied due to bridging therapy of oral anticoagulants. A monocentric retrospective two-arm matched cohort study (n=526 patients) was performed working out the incidence of major and minor postoperative bleeding as well as thromboembolic events, length of stay, and in-hospital mortality. In the results an increased postoperative incidence of major (8% vs. 1%; p < 0.001) and minor (14% vs. 5%; p < 0.001) bleeding events could be detected. Thromboembolic events were equally rare in both groups (1% vs. 2%; p = 0.45). On mortality no effect could be observed (1.5% vs. 1.9%). Furthermore, independent risk factors of major postoperative bleeding were full-therapeutic dose of LMWH, renal insufficiency, and the procedure-specific bleeding risk. Taking the above into account, routine bridging should be carefully considered in general and visceral surgery.

A blowout is an uncontrolled flow of reservoir fluids into the wellbore to the surface, causing serious, sometimes catastrophic, problems in different types of petroleum engineering operations. If the formation's strength is low and the pore pressure is high, bridging can be a very effective method for blowout containment. In this method, the formation caves into the open hole or onto the casing and stops the flow of the formation's fluid, either naturally or intentionally. This method can be effective in deepwater blowouts where the formation has high pore pressure and considerable shale intervals with low strength. In this research, wellbore stability and fluid flow performance subroutines have been developed with Visual Basic for Applications (VBA) programming. By integrating the subroutines together, we made a simulation tool to predict wellbore stability during blowouts and, consequently, predict wellbore bridging during normal and blowout situations. Then we used a real case in the country of Brunei to investigate a field case of a bridged wellbore to validate the simulator. In addition to the field case, we used GMI SFIB 5.02, a wellbore stability software, to provide validation. In the final part of this research we studied the effect of water depth in bridging tendency during blowout for the deepwater Gulf of Mexico (GOM). Since we could not find any real data in this area, we used general trends and correlations related to the GOM. The results of our study showed that water depth delays the occurrences of breakout in the wellbore during blowouts (i.e. for greater depth of water, wellbore collapse occurs farther below the mudline). However, the depth in which collapse occurs is different for different maximum horizontal stress amounts.

Contour laser transmission welding (LTW) is a technology that has potential for joining large and complicated thermoplastic parts. Thermal expansion is the primary driving force to bridge potential gaps at the weld. A comprehensive investigation into gap bridging was performed using experimental studies, finite element (FE) thermal-mechanical coupled modeling, and analytical analysis of the contour welding process for polycarbonate (PC), polyamide 6 (PA6) , and glass fibres reinforced polyamide 6 (PA6GF). The effects of material properties (carbon black level, glass fibres and crystallinity), process parameters (laser scan power, scan speed) and weld gap thickness on weld shear strength were assessed. The experimental study indicated that low concentration of laser absorbing pigment accompanied with high power laser scan improves gap bridging. Damage on the top surface of the laser-transparent part limited the allowable laser power that could be delivered onto the weld interface. Maximum gaps of 0.2, 0.4 and 0.25 mm were bridged in the experiment for the three types of polymers respectively. The thermal behavior of polymers in contour LTW was analyzed by the 3-D quasi-static thermal FE models. Thermal expansion into the gap was simulated by the simplified 2-D transient, thermal-mechanical coupled FE models. An analytical model describing laser beam transmission and absorption in light-scattering polymers was developed and applied in the FE simulation for PA6 and PA6GF. FE simulated results agree well with the experiment in contour welding with gap of PC and PA6. The optimum material and process parameters have been searched in the model to maximize gap bridging for PC. An analytical model has been developed to predict the temperature rise and the thermal expansion in high speed contour welding of amorphous polymers. The model indicates that the maximum temperature at weld increases linearly with the laser line energy and the laser absorption coefficient. Thermal expansion and hence gap bridging increases with laser line energy. Lower laser absorption coefficient allows higher laser scan energy to be delivered onto the weld interface so helps bridge larger gap. The predicted thermal expansions by the model agree well with the measured maximum gaps bridged for polycarbonate. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2009-09-24 22:24:11.734

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