Search PubMed⌕ Search

Biomedical subjects

C R Williams

Publications and source records attributed to C R Williams.

49 records · Page 3Linked to original sources
PubMed1983

Physico-chemical characterization of atmospheric trace metal emissions from a primary zinc-lead smelter.

Emissions from the stacks of a major primary zinc--lead smelter were characterised using X-ray powder diffraction spectrometry (XRD). The following chemical phases were identified: PbSO4, PbO X PbSO4, PbO, PbS, PbO, ZnO, alpha-ZnS, CdO. A complementary environmental investigation revealed that, within the works boundary, the airborne metals might be associated mainly with the fugitive blowage of coarse particles containing primary ore minerals. However, such fugitive emissions were found to be of low significance in the local environment outside the works perimeter, where fine particle emissions from the stacks of the smelter were the predominant source of airborne cadmium, lead and zinc.

Air Pollutants↗
PubMed1981

Structure of valinomycin-K+ complex in solution by extended x-ray absorption fine structure.

We used synchrotron radiation to measure the K-edge absorption spectra of the potassium ion in valinomycin-K+ complexes dissolved in ethanol and methanol. Our motivation is to study the structure of valinomycin around the potassium ion and the effect of solvents. From the extended x-ray absorption fine structure, we found that the mean distance from potassium to its coordination atoms, oxygen, is the same for both solvents, 2.79 +/- 0.02 A, compared with 2.76 A in crystal. The K-edge threshold spectra of the two solutions are almost identical but have a small difference in their relative peak intensities. The coincidence of their corresponding peak positions indicates that the strength of ligand field is about the same in these two samples. This agrees with the known binding energies of potassium ion to valinomycin in solutions. The difference in the relative peak intensities suggests a perturbation of ligand symmetry by solvents.

Chemical Phenomena↗
PubMedDate not supplied

Acute aortic occlusion as a late complication of coarctation repair.

Late morbidity and mortality following surgical correction of coarctation of the aorta in adults are primarily related to associated cardiovascular disease, especially persistent systemic hypertension and its sequelae. complications related to the site of coarctation repair are relatively uncommon in this age group and include residual and recurrent coarctation and aneurysm formation. An unusual case is presented in which dehiscence of the proximal suture line of a Dacron tube graft resulted in a flap-valve effect, pseudoaneurysm formation, and acute functional occlusion of the aorta. The angiographic findings are described and the relevant literature reviewed.

Adult↗