Characterization of carbon contamination under ion and hot atom bombardment in a tin-plasma extreme ultraviolet light source

Molecular contamination of a grazing incidence collector for extreme ultraviolet (EUV) lithography was experimentally studied. A carbon film was found to have grown under irradiation from a pulsed tin plasma discharge. Our studies show that the film is chemically inert and has characteristics that are typical for a hydrogenated amorphous carbon film. It was experimentally observed that the film consists of carbon (~70 at. %), oxygen (~20 at. %) and hydrogen (bound to oxygen and carbon), along with a few at. % of tin. Most of the oxygen and hydrogen are most likely present as OH groups, chemically bound to carbon, indicating an important role for adsorbed water during the film formation process. It was observed that the film is predominantly sp3 hybridized carbon, as is typical for diamond-like carbon. The Raman spectra of the film, under 514 and 264 nm excitation, are typical for hydrogenated diamond-like carbon. Additionally, the lower etch rate and higher energy threshold in chemical ion sputtering in H2 plasma, compared to magnetron-sputtered carbon films, suggests that the film exhibits diamond-like carbon properties.Comment: 18 pages, 10 figure

Survival After Endovascular Aneurysm Sealing Compared With Endovascular Aneurysm Repair

Introduction Endovascular aneurysm sealing (EVAS) is a sac-filling device with a blunted systemic inflammatory response compared to conventional endovascular aneurysm repair (EVAR), with a suggested impact on all-cause mortality. This study compares mortality after both EVAS and EVAR. Materials and Methods This is a retrospective observational study including data from 2 centres, with ethical approval. Elective procedures on asymptomatic infrarenal aneurysms performed between January 2011 until April 2018 were enrolled. Laboratory values (serum creatinine, haemoglobin, white blood cell count, platelet count) were measured pre- and postoperatively and at 1 and 2 years, respectively. Mortality and cause of death were recorded during follow-up. Results A total of 564 patients were included (225 EVAS, 369 EVAR), after propensity score matching there were 207 patients in both groups. Baseline characteristics were similar, except for larger neck angulation and more pulmonary disease in the EVAR group. The median follow-up time was 49 (EVAS) and 44 (EVAR) months. No significant differences regarding creatinine and haemoglobin were observed. Preoperative white blood cell count was higher in the EVAR group (p=0.011), without significant differences during follow-up. Median platelet count was lower in the EVAR group preoperatively (p=0.001), but was significantly higher at 1 year follow-up (p=0.003). There were 43 deaths within the EVAS group (20.8%) and 52 within the EVAR group (25.1%) (p=0.293). Of these, 4 were aneurysm related (EVAS n=3, EVAR n=1; p=0.222) and 14 cardiovascular (EVAS n=6, EVAR n=8, p=0.845). For the EVAS cohort, survival was 95.5% at 1 year and 74.9% at 5 years. For the EVAR cohort, this was 93.3% at 1 year and 75.5% at 5 years. No significant differences were observed in causes of death. Conclusion This study showed comparable survival rates through 5 years between EVAS and EVAR with a tendency toward higher inflammatory response in the EVAR patients through the first 2 years

The role of antiphase boundaries during ion sputtering and solid phase epitaxy of Si(001)

The Si(001) surface morphology during ion sputtering at elevated temperatures and solid phase epitaxy following ion sputtering at room temperature has been investigated using scanning tunneling microscopy. Two types of antiphase boundaries form on Si(001) surfaces during ion sputtering and solid phase epitaxy. One type of antiphase boundary, the AP2 antiphase boundary, contributes to the surface roughening. AP2 antiphase boundaries are stable up to 973K, and ion sputtering and solid phase epitaxy performed at 973K result in atomically flat Si(001) surfaces.Comment: 16 pages, 4 figures, to be published in Surface Scienc

Systematic Review on the Mid-Term Outcomes of Elective Endovascular Aneurysm Sealing in Comparison to Endovascular Aneurysm Repair

Introduction The Nellix endovascular aneurysm sealing (EVAS) system has been a topic of discussion. Early results were promising but did not deliver on the long-term and the device has been recalled from the market. This study compares literature for EVAS and conventional endovascular aneurysm repair (EVAR). Methods A systematic review and analysis was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. PubMed, Embase, and Cochrane Library were searched and identified the eligible studies. Proportion rates for the outcomes of interest were extracted. Subgroup analyses were performed for EVAS and EVAR. Results A total of 12 studies were included (EVAS n = 4, EVAR n = 8) including 10,255 patients (EVAS n = 784, EVAR n = 9441). The longest duration of follow-up was 3.4 years for EVAS and 5.0 years for EVAR studies. Throughout follow-up the overall all-cause mortality rates were 6% for EVAS and 13% for EVAR, and endoleak of any type was described in 10% of EVAS and 17% of EVAR patients. The migration rate &gt;10 mm was 8% for EVAS and 0% for EVAR and aneurysm growth &gt;5 mm was found in 11% of EVAS and 3% of EVAR cases. Total reintervention rate was 13% for EVAS and 7% for EVAR patients. For all analyzed outcome parameters heterogeneity was &gt;50%. Conclusion There is a tendency toward lower mortality and overall endoleak rates for EVAS compared to EVAR but with a higher rate of migration, aneurysm growth, and reintervention. Despite lower overall endoleak rates there was a tendency toward less type II and more type I endoleaks after EVAS compared to EVAR. Substantial heterogeneity however limits robust statistical analyses, and is probably caused by significant instructions for use breach in EVAS-treated patients. We call for more high-quality and long-term follow-up studies on both EVAS and EVAR in order to confirm the trends found in this study.</p

Development and external validation of preoperative clinical prediction models for postoperative outcomes including preoperative aerobic fitness in patients approaching elective colorectal cancer surgery

Introduction: Preoperative aerobic fitness is associated with postoperative outcomes after elective colorectal cancer (CRC) surgery. This study aimed to develop and externally validate two clinical prediction models incorporating a practical test to assess preoperative aerobic fitness to distinguish between patients with and without an increased risk for 1) postoperative complications and 2) a prolonged time to in-hospital recovery of physical functioning after elective colorectal cancer (CRC) surgery. Materials and methods: Models were developed using prospective data from 256 patients and externally validated using prospective data of 291 patients. Postoperative complications were classified according to Clavien-Dindo. The modified Iowa level of assistance scale (mILAS) was used to determine time to postoperative in-hospital physical recovery. Aerobic fitness, age, sex, body mass index, American Society of Anesthesiologists (ASA) classification, neoadjuvant treatment, surgical approach, tumour location, and preoperative haemoglobin level were potential predictors. Areas under the curve (AUC), calibration plots, and Hosmer-Lemeshow tests evaluated predictive performance. Results: Aerobic fitness, sex, age, ASA, tumour location, and surgical approach were included in the final models. External validation of the model for complications and postoperative recovery presented moderate to fair discrimination (AUC 0.666 (0.598–0.733) and 0.722 (0.651–0.794), respectively) and good calibration. High sensitivity and high negative predictive values were observed in the lower predicted risk categories (&lt;40 %). Conclusion: Both models identify patients with and without an increased risk of complications or a prolonged time to in-hospital physical recovery. They might be used for improving patient-tailored preoperative risk assessment and targeted and cost-effective application of prehabilitation interventions.</p

Development and external validation of preoperative clinical prediction models for postoperative outcomes including preoperative aerobic fitness in patients approaching elective colorectal cancer surgery

Introduction: Preoperative aerobic fitness is associated with postoperative outcomes after elective colorectal cancer (CRC) surgery. This study aimed to develop and externally validate two clinical prediction models incorporating a practical test to assess preoperative aerobic fitness to distinguish between patients with and without an increased risk for 1) postoperative complications and 2) a prolonged time to in-hospital recovery of physical functioning after elective colorectal cancer (CRC) surgery. Materials and methods: Models were developed using prospective data from 256 patients and externally validated using prospective data of 291 patients. Postoperative complications were classified according to Clavien-Dindo. The modified Iowa level of assistance scale (mILAS) was used to determine time to postoperative in-hospital physical recovery. Aerobic fitness, age, sex, body mass index, American Society of Anesthesiologists (ASA) classification, neoadjuvant treatment, surgical approach, tumour location, and preoperative haemoglobin level were potential predictors. Areas under the curve (AUC), calibration plots, and Hosmer-Lemeshow tests evaluated predictive performance. Results: Aerobic fitness, sex, age, ASA, tumour location, and surgical approach were included in the final models. External validation of the model for complications and postoperative recovery presented moderate to fair discrimination (AUC 0.666 (0.598–0.733) and 0.722 (0.651–0.794), respectively) and good calibration. High sensitivity and high negative predictive values were observed in the lower predicted risk categories (&lt;40 %). Conclusion: Both models identify patients with and without an increased risk of complications or a prolonged time to in-hospital physical recovery. They might be used for improving patient-tailored preoperative risk assessment and targeted and cost-effective application of prehabilitation interventions.</p

Effect of strain on surface diffusion in semiconductor heteroepitaxy

We present a first-principles analysis of the strain renormalization of the cation diffusivity on the GaAs(001) surface. For the example of In/GaAs(001)-c(4x4) it is shown that the binding of In is increased when the substrate lattice is expanded. The diffusion barrier \Delta E(e) has a non-monotonic strain dependence with a maximum at compressive strain values (e 0) studied. We discuss the consequences of spatial variations of both the binding energy and the diffusion barrier of an adatom caused by the strain field around a heteroepitaxial island. For a simplified geometry, we evaluate the speed of growth of two coherently strained islands on the GaAs(001) surface and identify a growth regime where island sizes tend to equalize during growth due to the strain dependence of surface diffusion.Comment: 10 pages, 8 figures, LaTeX2e, to appear in Phys. Rev. B (2001). Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm