Capturing metal-support interactions in situ during the reduction of a Re promoted Co/γ-Al2O3 catalyst.

The reduction of a Re promoted Co/γ-Al2O3 catalyst was monitored in situ by synchrotron X-ray powder diffraction (XRPD) under H2 environment. Whole powder pattern analysis revealed a non-linear expansion of the unit cell of γ-Al2O3 during the reduction process, suggesting the diffusion of Co cations into the structure of the support. The non-linear cell expansion coincided with the formation of a CoO phase. In addition, space resolved diffraction at the inlet and the outlet of the reactor evidenced a negative effect of the partial pressure of indigenous H2O(g) on the reduction process.

Catalytic ozonation of oxalic acid using carbon nanofibres on macrostructured supports.

Carbon nanofibres (CNFs) were grown on different macrostructured supports such as cordierite monoliths, carbon felts and sintered metal fibres. The resulting composites exhibited excellent resistance to attrition/corrosion and its porosity is mainly due to mesoporous structures. The CNF/structured materials were tested in the ozonation of oxalic acid in a conventional semi-batch reactor after being crushed to powder form, and in a newly designed reactor that may operate in semi-batch or continuous operation. The CNFs supported on the different structured materials exhibited high catalytic activity in the mineralization of oxalic acid.

Comparison of white, African American, Hispanic, and Asian children on the Naglieri Nonverbal Ability Test.

This study examined differences between 3 matched samples of White (n = 2,306) and African American (n = 2,306), White (n = 1,176) and Hispanic (n = 1,176), and White (n = 466) and Asian (n = 466) children on the Naglieri Nonverbal Ability Test (NNAT; J. A. Naglieri, 1997a). The groups were selected from 22,620 children included in the NNAT standardization sample and matched on geographic region, socioeconomic status, ethnicity, and type of school setting (public or private). There was only a small difference between the NNAT scores for the White and African American samples (d ratio = .25) and minimal differences between the White and Hispanic (d ratio = .17) and between the White and Asian (d ratio = .02) groups. The NNAT was moderately correlated with achievement for the total sample and correlated similarly with achievement for the White and ethnic minority groups. The median correlation of NNAT with reading was .52 and NNAT with math was .63 across the samples. Results suggest that the NNAT scores have use for fair assessment of White and minority children.

Different versions of the anatomical therapeutic chemical classification system and the defined daily dose--are drug utilisation data comparable?

OBJECTIVE: To investigate whether published drug utilisation studies contain satisfactory references to the ATC/DDD version applied and thus are usable for comparative purposes. METHODS AND RESULTS: A literature survey of drug utilisation studies was made. Seventy-three articles were identified by two Medline searches, one in 1996 and another in 1998. The articles were classified into four different groups. Groups 1 and 2 give proper references to the defined daily doses (DDDs) used in the studies, either by full reference to the version of the ATC Index with DDDs or by listing the actual DDDs used. The articles in groups 1 and 2 represent 46% of the articles in the survey. The articles classified in groups 3 and 4 give references only to general articles about the anatomical therapeutic chemical classification (ATC)/DDD system or no references at all. Fifty-four percent of the articles in the survey were classified in these groups. In these articles it is not possible to identify which DDDs have been used in the presentation of drug consumption data. CONCLUSIONS: According to the results from our literature survey, it is not common practice to include the ATC codes and the DDD values used or to make reference to the versions of the ATC/DDD index used when results from drug utilisation studies are published. One possible reason for this might be little or no knowledge about the ATC/DDD system as a dynamic system in which alterations are made annually. The lack of references to the actual DDDs used in the studies make comparisons between different data sets difficult and misleading.

The usage of veterinary antibacterial drugs for mastitis in cattle in Norway and Sweden during 1990-1997.

The prescribing patterns and annual incidence of use of antibacterial drugs for the treatment of mastitis in cattle in Norway and Sweden during the period 1990-1997 were estimated from drug wholesaler statistics. Although the drugs included in this study are also used in other species and/or other indications, mastitis in cattle is by far the most-common indication for their use. We used these sales figures to evaluate trends in the use of antibacterial drugs and changes in the incidence of treatment in bovine mastitis in Norway and Sweden. To facilitate comparisons (correcting for differences in activity and dosage) between the relative proportions of antibacterial drugs used in bovine mastitis, we introduced defined daily dose cow (DDDcow) as unit of measurement. Tentative DDDcow for the various injectable drugs were derived from doses recommended in Norway and Sweden. For intramammary drugs administered in the form of single-dose applicators, one applicator was defined as the DDDcow. The prescribing patterns of antibacterial drugs in bovine mastitis in Norway and Sweden during the study period seemed to be influenced by treatment policies, substances and formulations approved and treatment cost; length of the withdrawal period also seemed to play a role.

EXAFS study of zinc coordination in bacitracin A.

Bacitracin is a dodecapeptide antibiotic produced by Bacillus sp. The antibacterial activity depends upon the peptide binding a divalent metal. Hitherto, the exact coordination of the cation has not been established. In particular the role played by the sulphur and nitrogen atoms of the thiazoline ring of bacitracin A has not been clear. Here the coordination of Zn2+ by bacitracin A has been studied using extended X-ray absorption fine structure. The experimental data are consistent with a model in which zinc is coordinated by one oxygen and three nitrogen atoms with the sulphur atom of the thiazoline ring not being directly involved in the zinc coordination.

Surveillance of the overall consumption of antibacterial drugs in humans, domestic animals and farmed fish in Norway in 1992 and 1996.

The annual overall consumption of antibacterial drugs in Norway, categorized into human use, use in domestic animals and in farmed fish, was estimated from wholesaler and feed-mill sales statistics. Comprehensive data on drug consumption in human medicine in Norway are published on a regular basis on behalf of the drug authorities. These data, including use of antibacterial drugs, are expressed as the number of defined daily doses (DDD)/1000 inhabitants/year. DDD cannot be employed to compare antibiotic consumption in human and veterinary medicine as it is possible to calculate such data for only a few veterinary drugs. The only parameter for which data are generally available, so far, is the amount used in kilograms of active substance, which is the unit of measurement chosen in this study. It was found that annual overall sales of antibacterial drugs in Norway, including antibacterial and ionophore feed additives, decreased from 77 tonnes in 1992 to 49 tonnes in 1996, a 37% reduction. The use in 1996 in human medicine, animals and farmed fish was 35 tonnes, 13 tonnes and 1 tonne, respectively. While the annual amounts used in human medicine remained unchanged from 1992 to 1996, therapeutic use in fish farming declined by 96%. In domestic animals, therapeutic use and use as feed additives declined by 17% and 5%, respectively. During the study period, the size of the human and domestic animal populations at risk remained almost constant, while the biomass (weight) of farmed fish at risk increased by > 100%. This implies that both the absolute and relative consumption of antibacterial drugs in Norway decreased substantially during the study period. The use of antibacterial drugs, both in humans and in domestic animals, has changed in favour of penicillins, this being in accordance with general recommendations. The reduction in the use of antibacterial drugs in farmed fish has been almost solely due to the introduction of oil-adjuvanted vaccines against furuncolosis. It is concluded that the decline in the amount of antibacterial drugs used in domestic animals, and the changes with regard to choice of drugs, could be mainly attributed to changes in prescribing behaviour following advice and recommendations. Moreover, the overall use of antibacterial drugs in Norway is very low compared with that in most other countries and has been significantly reduced during the 1990s.