Spectroscopic evidence for origins of size and support effects on selectivity of Cu nanoparticle dehydrogenation catalysts.

Selective dehydrogenation catalysts that produce acetaldehyde from bio-derived ethanol can increase the efficiency of subsequent processes such as C-C coupling over metal oxides to produce 1-butanol or 1,3-butadiene or oxidation to acetic acid. Here, we use in situ X-ray absorption spectroscopy and steady state kinetics experiments to identify Cuδ+ at the perimeter of supported Cu clusters as the active site for esterification and Cu0 surface sites as sites for dehydrogenation. Correlation of dehydrogenation and esterification selectivities to in situ measures of Cu oxidation states show that this relationship holds for Cu clusters over a wide-range of diameters (2-35 nm) and catalyst supports and reveals that dehydrogenation selectivities may be controlled by manipulating either.

[Comparison of premedication with clonidine and midazolam combined with TCI for orthopaedic shoulder surgery]. / Vergleich der Prämedikationsqualität unterschiedlicher Clonidinkonzentrationen und Midazolam im Rahmen einer TCI bei orthopädischen Schulteroperationen.

OBJECTIVE: The most frequently used drugs for premedication are benzodiazepines and alpha (2)-adrenoceptor agonists. In this study we examined midazolam and clonidine for premedication in combination with target controlled infusion anaesthesia (TCI) in patients undergoing orthopaedic shoulder surgery and analysed the effects on the peri- and postoperative course. METHODS: Forty-five Patients (ASA I-III) were included in this prospective randomized, double blind study. Sixty minutes prior to anaesthetic induction the patients received clonidine in a dosage of 2 microg x kg(-1) (group ND) or 5 microg x kg(-1) (group HD) or 0.1 mg x kg(-1) midazolam (group midazolam) per orally. Anaesthesia was performed as TCI with propofol (plasma concentration 2.0-4.0 microg x ml(-1)) und remifentanil (plasma concentration 0.2-0.4 microg x ml(-1) x min(-1)). 15 minutes before the operation was finished, all patients received a bolus dose of 0.1 mg x kg(-1) piritramid i.v., followed by administration of piritramid via a PCA pump (patient controlled analgesia) for a duration of 24 hours. During the time of the operation the influence of premedication on the anaesthetic course was determined by vital parameters and ranking scales. For statistic evaluation we used the Kruskal-Wallis test, ANOVA with Tukey as post hoc test and the test named after Fisher (p < 0.05). RESULTS: The effects of premedication on haemodynamic parameters and ranking scales for sedation as well as anaesthetic requirements were comparable in all three groups. In the postoperative period the incidence of postoperative nausea and vomiting (PONV) (ND: n = 8, HD: n = 2, midazolam: n = 6) and the use of pritramid were lower in the clonidine HD group (HD: 38.7 +/- 30.7 mg, ND: 51.7 +/- 25.1 mg, midazolam: 45.1 +/- 30.4 mg) than in the other groups. CONCLUSIONS: Premedication with the alpha(2)-adrenoceptor agonist clonidine is as good as with benzodiazepines in combination with TCI. Because of the lower incidence of PONV and the need of piritramid in the postoperative period patients premedicated with 5 microg x kg(-1) clonidine may benefit from this premedication.

Mother-loss: recreating relationship and meaning.

The purpose of this investigation was to describe adult women's experiences in losing their mother. Using an interpretive phenomenological frame of inquiry, 5 women were purposively selected to share their loss experience. Memories of the mother-daughter relationship were explored, and the meanings the daughters attached to their loss described, in written narratives, 2 in-depth interviews, and 1 group session. Seven themes emerged: Recalling, Holding On, Saying Goodbye, Longings of the Heart, Shifting Patterns of Relationship, Recreating the Dialogue, and Honouring Our Mothers/Ourselves. The loss of one's mother represents the loss of one's first intimate relationship, a relationship that has a unique meaning for daughters because their personal development is profoundly and uniquely shaped by it. This potentially pervasive and transforming life experience is best understood from an in-depth exploration and understanding of the nature of the mother-daughter relationship. Nurses who come to understand the dynamic interaction of grief and development through women's experience of mother-loss can more successfully offer their presence, their understanding of the complexity of the mother-daughter relationship, and their skills in bereavement care to facilitate healing and to promote health and personal growth.