The catalytic combustion of methane has been investigated over eight different bimetallic palladium catalysts, comprising the co-metals Co, Rh, Ir, Ni, Pt, Cu, Ag, or Au. The catalysts were ...characterized by TEM, EDS, PXRD, and temperature-programmed oxidation (TPO). It was found that a catalyst containing both Pd and Pt was the most promising, as it had a high activity that did not decline with time. The catalyst containing Pd and Ag was also a promising candidate, but its activity was slightly lower. For PdCo and PdNi, the co-metals formed spinel structures with the alumina support, with the result that the co-metals did not affect the combustion performance of palladium. For PdRh, PdIr, PdCu, and PdAg, the co-metals formed separate particles consisting of the corresponding metal oxide. These catalysts, except PdRh, showed a stable activity. For PdPt and PdAu, the co-metals formed alloys with palladium, and both catalysts showed a stable activity.
Background: Low plasma glutamine concentration is an independent prognostic factor for an unfavourable outcome in the intensive care unit (ICU). Intravenous (i.v.) supplementation with glutamine is ...reported to improve outcome. In a multi‐centric, double‐blinded, controlled, randomised, pragmatic clinical trial of i.v. glutamine supplementation for ICU patients, we investigated outcomes regarding sequential organ failure assessment (SOFA) scores and mortality. The hypothesis was that the change in the SOFA score would be improved by glutamine supplementation.
Methods: Patients (n=413) given nutrition by an enteral and/or a parenteral route with the aim of providing full nutrition were included within 72 h after ICU admission. Glutamine was supplemented as i.v. l‐alanyl‐l‐glutamine, 0.283 g glutamine/kg body weight/24 h for the entire ICU stay. Placebo was saline in identical bottles. All included patients were considered as intention‐to‐treat patients. Patients given supplementation for >3 days were considered as predetermined per protocol (PP) patients.
Results: There was a lower ICU mortality in the treatment arm as compared with the controls in the PP group, but not at 6 months. For change in the SOFA scores, no differences were seen, 1 (0,3) vs. 2 (0.4), P=0.792, for the glutamine group and the controls, respectively.
Conclusion: In summary, a reduced ICU mortality was observed during i.v. glutamine supplementation in the PP group. The pragmatic design of the study makes the results representative for a broad range of ICU patients.
The catalytic oxidation of methane was investigated over six catalysts with different palladium and platinum molar ratios. The catalysts were characterised by TEM, EDS, XPS, PXRD and ...temperature-programmed oxidation. The results suggest that in the bimetallic catalysts, an alloy between Pd and Pt was formed in close contact with the PdO phase, with an exception for the Pt-rich catalyst, where no PdO was observed. It was found that the molar ratio between palladium and platinum clearly influences both the activity and the stability of methane conversion. By adding small amounts of platinum into the palladium catalyst, improved activity was obtained in comparison with the monometallic palladium catalyst. However, higher amounts of platinum are required for stabilising the methane conversion. The most promising catalysts with respect to both activity and stability were Pd
67Pt
33 and Pd
50Pt
50. The platinum-rich catalyst showed very poor activity for methane conversion.
Background
Therapeutic hypothermia (TH) is a promising treatment of stroke, but limited data are available regarding the safety and effectiveness of cooling methodology. We investigated the safety of ...TH and compared the cooling capacity of two widely used cooling strategies – endovascular and surface cooling.
Methods
COOLAID Oresund is a bicentre randomized trial in Copenhagen (Denmark) and Malmö (Sweden). Patients were randomized to either TH (33°C for 24 h) in a general intensive care unit (ICU) or standardized stroke unit care (control). Cooling was induced by a surface or endovascular‐based strategy.
Results
Thirty‐one patients were randomized. Seven were cooled using endovascular and 10 using surface‐based cooling methods and 14 patients received standard care (controls). 14 (45%) patients received thrombolysis. Pneumonia was recorded in 6 (35%) TH patients and in 1 (7%) control. 4 TH patients and 1 control developed massive infarction. 1 TH patient and 2 control suffered asymptomatic haemorrhagic transformation. Mortality was comparable with 2 (12%) in the TH group and 1 (7%) among controls. Mean (SD) duration of hospital stay was 25.0 days (24, 9) in TH and 22.5 days (20.6) in control patients (P = 0.767). Mean (SD) induction period (cooling onset to target temperature) was 126.3 min (80.6) with endovascular cooling and 196.3 min (76.3) with surface cooling (P = 0.025).
Conclusions
Therapeutic hypothermia with general anaesthesia is feasible in stroke patients. We noticed increased rates of pneumonia, while the length of hospital stay remained comparable. The endovascular cooling strategy provides a faster induction period than surface cooling.
Background: Becoming critical ill or severely injured leads to a process of worry, anxiety and pain. Patients in intensive care sometimes have strange and frightening experiences and may show ...symptoms of acute confusion or delirium. CAM‐ICU, the confusion assessment method for the intensive care unit, was based on the DSM IV, the Diagnostic and Statistic Manual of Mental Disorders IV, and today, healthcare professionals and researchers are increasingly accepting this concept of diagnosing ICU delirium. In Sweden, there is no commonly used, single instrument or method to test the development of ICU delirium. The aim of this study was to translate, retranslate and validate CAM‐ICU for use in Swedish ICU settings.
Methods: The translation of the instrument was done according to the guidelines suggested by The Translation and Cultural Adaptation group which includes preparation, forward translation/reconciliation, back translation, back translation review, harmonization, cognitive debriefing and validation. In the validation process, the applicability of the Swedish version of the instruments was tested in a Swedish intensive care unit.
Results: Fourteen adult patients were included in the study, 40 paired tests were carried out, and 80 CAM‐ICU instruments were completed. The participating patients were given CAM‐ICU ratings using independent paired evaluations by two nurses, specialized in intensive care, at least twice during the patients’ stay in the ICU. Interrater reliability was calculated using kappa statistics. In the 40 paired observations, interrater reliability was ‘very good’ (kappa statistics > 0.81). In our material, we recognized a delirium rate of 48%, which is in accordance with previous studies.
Conclusion: The translation of the instrument CAM‐ICU showed good correlation with the original version and could therefore be applicable in a Swedish ICU setting. In the 40 paired observations, interrater reliability was very good. Although there are limitations in using CAM‐ICU, previous studies reveal a need for a homogeneous screening instrument making it possible to detect and determine ICU delirium; and from this basis are able to implement and make the necessary decisions required in medical and nursing care practice preventing ICU delirium.
The effects of adding a co-metal, Pt or Rh, to Pd/γ-Al
2O
3 catalysts were studied with respect to the catalytic activity for methane combustion and compared to a Pd/γ-Al
2O
3 catalyst, using both a ...pressurized pilot-scale and a lab-scale annular reactor. Temperature programmed oxidation (TPO) experiments were also carried out to investigate the oxygen release/uptake of the catalyst materials. Palladium showed an unstable behavior both in the pilot and lab-scale experiments at temperatures well below the PdO to Pd transformation. An addition of Pt to Pd stabilized, and in some cases increased, the catalytic activity for methane combustion.
The TPO experiments showed that the oxygen release peak was shifted to lower temperatures even for low additions of Pt, i.e. Pd:Pt=2:1. For additions of rhodium only small beneficial effects were seen. The steady-state behavior of the lab-scale annular reactor correspond well to the pressurized pilot-scale tests.
Catalytic combustion of methane over a supported bimetallic Pd-Pt catalyst and a monometallic Pd catalyst has been investigated experimentally. Two different reactor configurations were used in the ...study, i.e. a tubular lab-scale reactor working at atmospheric pressure and a high-pressure reactor working at up to 15
bar. The results showed that the bimetallic catalyst has a clearly more stable activity during steady-state operation compare to the palladium only catalyst. The activity of the bimetallic catalyst was slightly higher than for the palladium catalyst. These results were established in both test facilities. Further, the impact of pressure on the combustion activity has been studied experimentally. The tests showed that the methane conversion decreases with increasing pressure. However, the impact of pressure is more prominent at lower pressures and levels out for pressures above 10
bar.
Culture and Politics provides a comprehensive introduction to the enduring phenomenon of culture and its impact on contemporary society and politics. Combining a substantial theoretical overview with ...intricate comparative empirical research, it assesses the complex interplay of ethnicity, religion, history and values on macro- and micro-level outcomes. Striking a judicious balance between the use of global data on the topic and their selection of six key in-depth country studies, the book draws extensively on statistical material and 'hard data' rather than the literary evidence usual in studies of this kind. This second edition of a well-established text has been expanded and fully updated in line with new events. More student-friendly, this volume now contains useful references for further reading and new material on ethnicity and religion. Readers will find that the values section is now more lucid. This clearly structured book's stringent approach to the topic and its readable, accessible style make this book one that no serious scholar or student of political culture should be without.
Background: Myocardial dysfunction occurs commonly in septic shock. It is not known whether this is due to local ischaemia and metabolic disturbances. Our hypothesis was that endotoxaemic myocardial ...dysfunction may be associated with interstitial ischaemic and metabolic changes, measured using interstitial microdialysis (MD).
Methods: Eighteen pigs were randomized to control (n=6) or endotoxin infusion (n=12). MD catheters were inserted into the myocardium for measurement of interstitial glucose, pyruvate and lactate concentrations. Plasma glucose and lactate concentrations and systemic haemodynamic parameters were measured simultaneously.
Results: Compared with the control group, the endotoxaemic animals had significantly decreased left ventricular stroke work and venous oxygen saturation (SvO2), and increased mean pulmonary artery pressure and plasma lactate. In the endotoxaemic group, decreases in interstitial glucose were observed, occurring simultaneously with increases in interstitial pruvate. Interstitial lactate : pyruvate ratios decreased with time in all animals.
Conclusions: Despite severe systemic and pulmonary haemodynamic changes, interstitial MD measurements revealed no evidence of anaerobic metabolism in the myocardium of endotoxaemic pigs. There were, however, changes in glucose and pyruvate concentrations, suggesting local energy metabolic disturbances.
The main objective of catalytic combustion is to attain a flame temperature 300–400
K lower than in thermal or non-catalyzed combustion; this substantially reduces the direct combination of nitrogen ...and oxygen in air to form the so-called thermal NO
x
. In this way, catalytic combustion is a preventive solution to the problem of nitrogen oxides emissions. The focus of attention here is its application in gas turbines, both for power production and for transportation by road, sea and air. Any catalyst for catalytic combustion, however, has to face extreme demands: continuous operation above 1000°C in the presence of oxygen and steam for preferably 30,000
h, resistance to poisons in the fuel and/or process air, and ability to withstand large thermal and mechanical shocks. While material/catalyst advances are still inadequate, systems engineering is coming to the rescue by developing multiple-monolith catalyst systems and the so-called hybrid reactors. The deactivation of catalyst supports, washcoats, and active materials is briefly reviewed here: sintering, vaporization, phase transformation, thermal shock and poisoning.
