Insights into the function of silver as an oxidation catalyst by ab initio, atomistic thermodynamics

To help understand the high activity of silver as an oxidation catalyst, e.g., for the oxidation of ethylene to epoxide and the dehydrogenation of methanol to formaldehyde, the interaction and stability of oxygen species at the Ag(111) surface has been studied for a wide range of coverages. Through calculation of the free energy, as obtained from density-functional theory and taking into account the temperature and pressure via the oxygen chemical potential, we obtain the phase diagram of O/Ag(111). Our results reveal that a thin surface-oxide structure is most stable for the temperature and pressure range of ethylene epoxidation and we propose it (and possibly other similar structures) contains the species actuating the catalysis. For higher temperatures, low coverages of chemisorbed oxygen are most stable, which could also play a role in oxidation reactions. For temperatures greater than about 775 K there are no stable oxygen species, except for the possibility of O atoms adsorbed at under-coordinated surface sites Our calculations rule out thicker oxide-like structures, as well as bulk dissolved oxygen and molecular ozone-like species, as playing a role in the oxidation reactions.Comment: 15 pages including 9 figures, Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

Extended CMOS 5. Zwischen- und Abschlussbericht

SIGLEAvailable from TIB Hannover: F03B1537 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman

Follow-up of the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA 2) 1991-2003: methods and characterization of participants

OBJECTIVES: The Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) was designed to investigate the health effects from long-term exposure to air pollution. METHODS: The health assessment at recruitment (1991) and at the first reassessment (2001-3) consisted of an interview about respiratory health, occupational and other exposures, spirometry, a methacholine bronchial challenge test, end-expiratory carbon monoxide (CO) measurement and measurement for atopy. A bio bank for DNA and blood markers was established. Heart rate variability was measured using a 24-hour ECG (Holter) in a random sample of participants aged 50 years and older. Concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3) and particulates in ambient air have been monitored in all study areas since 1991. Residential histories collected over the 11 year follow-up period coupled with GIS modelling will provide individual long-term air pollutant exposure estimates. RESULTS: Of 9651 participants examined in 1991, 8715 could be traced for the cohort study and 283 died. Basic information about health status was obtained for 8047 individuals (86% of alive persons), 6 528 individuals (70%) agreed to the health examination and 5 973 subjects (62%) completed the entire protocol. Non-participants in the reassessment were on average younger than participants and more likely to have been smokers and to have reported respiratory symptoms in the first assessment. Average weight had increased by 5.5 kg in 11 years and 28% of smokers in 1991 had quit by the time of the reassessment

Joint effect of obesity and TNFA variability on asthma: two international cohort studies

Obesity is a risk factor for asthma. Adipose tissue expresses pro-inflammatory molecules including tumour necrosis factor (TNF), and levels of TNF are also related to polymorphisms in the TNF-a (TNFA) gene. The current authors examined the joint effect of obesity and TNFA variability on asthma in adults by combining two population-based studies. The European Community Respiratory Health Survey and the Swiss Cohort Study on Air Pollution and Lung and Heart Disease in Adults used comparable protocols, questionnaires and measures of lung function and atopy. DNA samples from 9,167 participants were genotyped for TNFA -308 and lymphotoxin-a (LTA) +252 gene variants. Obesity and TNFA were associated with asthma when mutually adjusting for their independent effects (odds ratio (OR) for obesity 2.4, 95% confidence interval (CI) 1.7–3.2; OR for TNFA -308 polymorphism 1.3, 95% CI 1.1–1.6). The association of obesity with asthma was stronger for subjects carrying the G/A and A/A TNFA -308 genotypes compared with the more common G/G genotype, particularly among nonatopics (OR for G/A and A/A genotypes 6.1, 95% CI 2.5–14.4; OR for G/G genotype 1.7, 95% CI 0.8–3.3). The present findings provide, for the first time, evidence for a complex pattern of interaction between obesity, a pro-inflammatory genetic factor and asthma

Insights into the evolution of social systems and species from baboon studies

Baboons, members of the genus Papio, comprise six closely related species distributed throughout sub-Saharan Africa and southwest Arabia. The species exhibit more ecological flexibility and a wider range of social systems than many other primates. This article summarizes our current knowledge of the natural history of baboons and highlights directions for future research. We suggest that baboons can serve as a valuable model for complex evolutionary processes, such as speciation and hybridization. The evolution of baboons has been heavily shaped by climatic changes and population expansion and fragmentation in the African savanna environment, similar to the processes that acted during human evolution. With accumulating long-term data, and new data from previously understudied species, baboons are ideally suited for investigating the links between sociality, health, longevity and reproductive success. To achieve these aims, we propose a closer integration of studies at the proximate level, including functional genomics, with behavioral and ecological studies

West German Study PlanB Trial: Adjuvant Four Cycles of Epirubicin and Cyclophosphamide Plus Docetaxel Versus Six Cycles of Docetaxel and Cyclophosphamide in HER2-Negative Early Breast Cancer

PURPOSE The West German Study Group PlanB trial evaluated an anthracycline-free chemotherapy standard (six cycles of docetaxel and cyclophosphamide [TC]) in the routine treatment of human epidermal growth factor receptor 2-negative early breast cancer (EBC). PATIENTS AND METHODS Patients with pT1 to pT4c, all pN+, and pN0/high-risk EBC were eligible. High-risk pN0 was defined by one or more of the following: pT greater than 2, grade 2 to 3, high urokinase-type plasminogen activator/plasminogen activator inhibitor-1, hormone receptor (HR) negativity, and less than 35 years of age. After an early amendment, all HR-positive tumors underwent recurrence score (RS) testing, with chemotherapy omission recommended in RS less than or equal to 11 pN0 to pN1 disease. Patients were randomly assigned to four cycles of epirubicin (E)(90)/cyclophoshamide (C)(600) followed by four cycles of docetaxel (T)(100) or six cycles of T75C600 (administered once every 3 weeks). The primary end point was disease-free survival (DFS); secondary end points were overall survival (OS) and safety. The protocol specified P = .05 for a noninferiority margin of 4.4% for all patients combined. RESULT Of the 3,198 registered patients, 348 (RS <= 11) omitted chemotherapy, and 401 were not randomly assigned. The intention-to-treat population included 2,449 patients (1,227 EC-T v 1,222 TC: postmenopausal, 62.2% v60.8%; pNO, 58.2% v59.5%; pT1, 57.6% v52.3%; HR positive, 81.4% v82.2%; RS greater than 25 [in H.R-positive patients], 26.2% v 27.5%). Within the safety population (1,167 v 1,178 patients), 87.5% v 93.0% completed therapy. After a 60-month median follow-up, 5-year outcomes were similar in the EC-T and TC arms (DFS, 89.6% [95% CI, 87.9% to 91.5%] v89.9% [95% CI, 88.1% to 91.8%]; OS, 94.5% [95% CI, 93.1% to 95.9%] v94.7% [95% CI, 93.3% to 96.1%]). The DFS difference was within the noninferiority margin of the original trial design. Five treatment-related deaths were reported for TC (one for EC-T), despite a trend toward more-severe adverse events in the latter. Interaction analysis revealed no predictive trends with respect to key factors, including triple-negative, luminal A/B-like, pN, age, and RS status. CONCLUSION In the West German Study Group PlanB trial, 5-year outcomes for TC and EC-T were equally excellent. Six cycles of TC is an effective/safe option in human epidermal growth factor receptor 2-negative EBC with pN0 high genomic risk or pN1 EBC with genomically intermediate- to high-risk disease. (C) 2019 by American Society of Clinical Oncolog