Formation and destruction of polycyclic aromatic hydrocarbon clusters in the interstellar medium

The competition between the formation and destruction of coronene clusters under interstellar conditions is investigated theoretically. The unimolecular nucleation of neutral clusters is simulated with an atomic model combining an explicit classical force field and a quantum tight-binding approach. Evaporation rates are calculated in the framework of the phase space theory and are inserted in an infrared emission model and compared with the growth rate constants. It is found that, in interstellar conditions, most collisions lead to cluster growth. The time evolution of small clusters (containing up to 312 carbon atoms) was specifically investigated under the physical conditions of the northern photodissociation region of NGC 7023. These clusters are found to be thermally photoevaporated much faster than they are reformed, thus providing an interpretation for the lowest limit of the interstellar cluster size distribution inferred from observations. The effects of ionizing the clusters and density heterogeneities are also considered. Based on our results, the possibility that PAH clusters could be formed in PDRs is critically discussed.Comment: 14 pages, 14 figures. Astronomy & Astrophysics, accepted for publicatio

2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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Role of Factor VII in Correcting Dilutional Coagulopathy and Reducing Re-operations for Bleeding Following Non-traumatic Major Gastrointestinal and Abdominal Surgery

Objective The objective of this study is to evaluate the effectiveness of rfVIIa in reducing blood product requirements and re-operation for postoperative bleeding after major abdominal surgery. Background Hemorrhage is a significant complication after major gastrointestinal and abdominal surgery. Clinically significant bleeding can lead to shock, transfusion of blood products, and re-operation. Recent reports suggest that activated rfVIIa may be effective in correcting coagulopathy and decreasing the need for re-operation. Methods This study was a retrospective review over a 4-year period of 17 consecutive bleeding postoperative patients who received rfVIIa to control hemorrhage and avoid re-operation. Outcome measures were blood and clotting factor transfusions, deaths, thromboembolic complications, and number of re-operations for bleeding. Results Seventeen patients with postoperative hemorrhage following major abdominal gastrointestinal surgery (nine pancreas, four sarcoma, two gastric, one carcinoid, and one fistula) were treated with rfVIIa. In these 17 patients, rfVIIa was administered for 18 episodes of bleeding (dose 2,400-9,600 mcg, 29.8-100.8 mcg/kg). Transfusion requirement of pRBC and FFP were each significantly less than pre-rfVIIa. Out of the 18 episodes, bleeding was controlled in 17 (94%) without surgery, and only one patient returned to the operating room for hemorrhage. There were no deaths and two thrombotic complications. Coagulopathy was corrected by rfVIIa from 1.37 to 0.96 (p<0.0001). Conclusion Use of rfVIIa in resuscitation for hemorrhage after non-traumatic major abdominal and gastrointestinal surgery can correct dilutional coagulopathy, reducing blood product requirements and need for re-operation

withdrawn 2017 hrs ehra ecas aphrs solaece expert consensus statement on catheter and surgical ablation of atrial fibrillation

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Sociodemographic disparities in concomitant left atrial appendage occlusion during cardiac valve operations.

BackgroundSociodemographic disparities in atrial fibrillation (AF) management and thromboembolic prophylaxis have previously been reported, which may involve inequitable access to left atrial appendage occlusion (LAAO) during cardiac surgery. The present study aimed to evaluate the association of LAAO utilization with sex, race, and hospital region among patients with AF undergoing heart valve operations.MethodsAdults with AF undergoing valve replacement/repair in the 2012-2019 National Inpatient Sample were identified and stratified based on concurrent LAAO. Multivariable linear and logistic regressions were developed to identify factors associated with LAAO utilization. Mortality, complications including stroke and thromboembolism, hospitalization costs and length of stay (LOS) were secondarily assessed.ResultsOf 382,580 patients undergoing valve operations, 18.7% underwent concomitant LAAO. Over the study period, the proportion of female patients receiving LAAO significantly decreased from 44.8% to 38.9% (p<0.001). Upon risk adjustment, female (AOR 0.93 [95% CI 0.89-0.97]) and Black patients (0.91 [0.83-0.99]) had significantly reduced odds of undergoing LAAO compared to males and Whites, respectively. Additionally, hospitals in the Midwest (1.38 [1.24-1.51]) and West (1.26 [1.15-1.36]) had increased likelihood of LAAO whereas Northeast hospitals (0.85 [0.77-0.94)] had decreased odds relative to the South. Furthermore, LAAO was associated with decreased stroke (0.71 [0.60-0.84]) and thromboembolism (0.68 [0.54-0.86]), $4,200 reduction in costs and 1-day decrement in LOS.ConclusionsFemale and Black patients had significantly lower odds while Midwest and Western hospitals had greater odds of LAAO utilization. Enhancing access to LAAO during valvular surgery is warranted to improve clinical and financial outcomes for patients with AF