Relating catalyst structure and composition to the water–gas shift activity of Cu–Zn-based mixed-oxide catalysts

In order to investigate the effect of cerium oxide on Cu–Zn-based mixed-oxide catalysts four catalyst samples were characterized by means of XRD, in situ XANES and thermogravimetric analysis. The activity of the catalyst samples was tested for the forward water–gas shift reaction. Cerium oxide was found to increase the crystallinity of the ZnO phase indicating a segregation of the Cu and ZnO phases. The TOF of the water–gas shift reaction based on chemisorption data was found to be independent of composition and preparation conditions of the four catalyst samples. In contrast, the catalyst stability depends on composition and preparation conditions. Cerium oxide impregnated before calcination of the hydrotalcite-based Cu–Zn precursors leads to a more stable water–gas shift catalyst.     

Separate assessment of porosity and uncombined carbon in cemented carbides

Porosity and uncombined carbon in cemented carbides are traditionally assessed by comparison to standardized microstructure charts, such as those in ISO 4505-1978. To improve the accuracy in the characterization a fully automatic image analysis procedure has been developed. The analysis is performed using light optical microscopy on unetched polished specimens. The implemented algorithm separates uncombined carbon, C-defects, from pores, A- and B-defects. Pores are approximately distributed in a random way in the structure. Uncombined carbon is on the other hand precipitated into clusters of carbon particles. This difference is together with defect size used as a base for the separation. Small defects situated close together are classified as C-defects, small isolated defects as A-pores and large defects as B-pores. Pores are found to be more round than the somewhat elongated C-defects. The difference in shape is significant and can also be used as a separation criterion.

Image analysis is used to quantitatively characterise the ISO 4505-1978 standard charts with respect to volume fraction, number density and size distribution of defects. The results are compared to measured distributions for true microstructures.     

Identification of clinical yeast isolates by using the Microring YT

We investigated predisposing factors for the development of heterotopic ossification in a retrospective study of 637 hip arthroplasties, of which 484 were unilateral, 62 bilateral and 29 revision operations. The frequency of heterotopic ossification after a primary hip arthroplasty was 57 percent. In a univariate analysis, men, patients with hypertrophic arthrosis, and cemented arthroplasty were all at risk of developing heterotopic ossification. After a multivariate analysis, the male sex and the cemented arthroplasty remained as significant factors. In bilateral operations, the contralateral side developed heterotopic ossification in 82 percent when the primary hip operation had already caused ossification. There was no increase in ossifications after the contralateral operation. Half of the revision operations had an increase of heterotopic ossification from 1 to 4 Brooker classes.     

Expert performance: Its structure and acquisition.

Counter to the common belief that expert performance reflects innate abilities and capacities, recent research in different domains of expertise has shown that expert performance is predominantly mediated by acquired complex skills and physiological adaptations. For elite performers, supervised practice starts at very young ages and is maintained at high daily levels for more than a decade. The effects of extended deliberate practice are more far-reaching than is commonly believed. Performers can acquire skills that circumvent basic limits on working memory capacity and sequential processing. Deliberate practice can also lead to anatomical changes resulting from adaptations to intense physical activity. The study of expert performance has important implications for our understanding of the structure and limits of human adaptation and optimal learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A detailed analysis of ambipolar diffusion in nanostructured metal oxide films

In this paper a transport equation is derived which describes the behaviour of the nanostructured metal oxide films in a photoelectrochemical cell. It is shown that a detailed analysis of the charge compensation mechanism necessarily leads to a transport equation with characteristics similar to but logically distinct from the pure diffusion equation. The studied phenomenon was named ambipolar diffusion in the early 1950s. It takes into account the fact that the diffusion processes of ions and electrons occur at different speeds. A weak electric field therefore couples the processes together to preserve charge neutrality. The electric field in turn affects the transport resulting in a deviation from purely diffusive behaviour. However, this has not been widely recognised in the literature for nanostructured semiconductor films until very recently. In this paper a detailed analysis is presented. It is based on the assumption that the current density is solenoidal. It is shown that application of the ambipolar diffusion model to a photoelectrochemical cell based on a nanostructured metal oxide film leads to an additional term in the transport equation, rather than only a new diffusion coefficient as in earlier work. It is also shown that the boundary conditions interact closely with the equation to form a transport model.     

Existence of discrete-time LQG-controllers

Existence results for the LQG-controller are investigated. An infimal Riccati equation based controller may potentially give closed loop eigenvalues on the unit circle. Assuming left and right invertibility it is shown that there exists an optimal controller if and only if the Riccati equation based controller stabilizes the closed loop system after removal of all its unobservable and uncontrollable modes. Furthermore this reduced controller is the optimal controller, and its transfer function is unique. This existence condition is a considerable simplification of the more general geometric condition recently derived by Trentelman and Stoorvogel.     

Treatment of chronic cardiac insufficiency with coenzyme Q10, results of meta-analysis in controlled clinical trials

Meta-analysis applied to eight controlled clinical trials of coenzyme Q10 (CoQ10)-treatment of congestive heart failure revealed a significant improvement a several important cardiac parameters such as ejection fraction (EF), stroke volume (SV), cardiac output (CO), cardiac index (CI) and end diastolic volume index (EDVI). Concerning the improvement in SV and CO the average patient in the CoQ10 group had a higher score than respectively 76% and 73% of the patients in the placebo group. The improvement in CO and SV was also significant when considering of homogeneity. Additional controlled clinical trials seem justified which may strengthen the power of the meta-analyses. However, based on available results, it can not be excluded that CoQ10 may have a future role a adjunctive therapy in a dosage of 100-200 mg/day in the treatment of chronic congestive heart failure.     

Epididymo-orchitis and Reiter''s disease. Two infrequent complications after intravesical bacillus Calmette-Guérin therapy

Two cases of adverse reactions to intravesical treatment with bacillus Calmette-Guérin are reported. The first patient presented with a severe suppurating epididymo-orchitis three months after his last treatment. The second patient developed Reiter's disease with arthritis of one knee and conjunctivitis 1 week after the fourth instillation.