Structural behaviour of copper chloride catalysts during the chlorination of CO to phosgene

The interaction of CO with an attapulgite-supported Cu(II)Cl2 catalyst has been examined in a micro-reactor arrangement. CO exposure to the dried, as-received catalyst at elevated temperatures leads to the formation of CO2 as the only identifiable product. However, phosgene production can be induced by a catalyst pre-treatment where the supported Cu(II)Cl2 sample is exposed to a diluted stream of chlorine. Subsequent CO exposure at ~ 370°C then leads to phosgene production. In order to investigate the origins of this atypical set of reaction characteristics, a series of x-ray absorption experiments were performed that were supplemented by DFT calculations. XANES measurements establish that at the elevated temperatures connected with phosgene formation, the catalyst is comprised of Cu+ and a small amount of Cu2+. Moreover, the data show that unique to the chlorine pre-treated sample, CO exposure at elevated temperature results in a short-lived oxidation of the copper. On the basis of calculated CO adsorption energies, DFT calculations indicate that a mixed Cu+/Cu2+ catalyst is required to support CO chemisorption

A decade of living lobar lung transplantation: recipient outcomes

AbstractObjectiveLiving lobar lung transplantation was developed as a procedure for patients considered too ill to await cadaveric transplantation.MethodsOne hundred twenty-eight living lobar lung transplantations were performed in 123 patients between 1993 and 2003. Eighty-four patients were adults (age, 27 ± 7.7 years), and 39 were pediatric patients (age, 13.9 ± 2.9 years).ResultsThe primary indication for transplantation was cystic fibrosis (84%). At the time of transplantation, 67.5% of patients were hospitalized, and 17.9% were intubated. One-, 3-, and 5-year actuarial survival among living lobar recipients was 70%, 54%, and 45%, respectively. There was no difference in actuarial survival between adult and pediatric living lobar recipients (P = .65). There were 63 deaths among living lobar recipients, with infection being the predominant cause (53.4%), followed by obliterative bronchiolitis (12.7%) and primary graft dysfunction (7.9%). The overall incidence of acute rejection was 0.8 episodes per patient. Seventy-eight percent of rejection episodes were unilateral. Age, sex, indication, donor relationship, preoperative hospitalization status, use of preoperative steroids, and HLA-A, HLA-B, and HLA-DR typing did not influence survival. However, patients on ventilators preoperatively had significantly worse outcomes (odds ratio, 3.06, P = .03; Kaplan-Meier P = .002), and those undergoing retransplantation had an increased risk of death (odds ratio, 2.50).ConclusionThese results support the continued use of living lobar lung transplantation in patients deemed unable to await a cadaveric transplantation. We consider patients undergoing retransplantations and intubated patients to be at significantly high risk because of the poor outcomes in these populations

The medical student

The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

Nuclear astrophysics with radioactive ions at FAIR

The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes