Synthesis and characterisation of ferrihydrite/silica co-precipitates.

The effect of the presence of soluble silicates on ferrihydrite precipitation and some properties of the products formed in co-precipitation of ferrihydrite and silica have been investigated. The co-precipitates were formed using a continuous crystallisation process in which a combined iron/silicon feed solution was reacted with sodium hydroxide at a constant rate, while maintaining pH at 2.65 and temperature at 85 degrees C. The products of co-precipitation and the supernatant solutions were characterised using a variety of analytical techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM) and surface charge measurements. The addition of silicates was shown to have a significant impact on the crystallinity and surface charge of the precipitates formed. For products collected after five residence times in the continuous crystalliser, co-precipitates formed from ferric sulfate solution were found to contain considerably less silica than those formed from ferric nitrate. We conclude that adsorption of silicate species on ferrihydrite surfaces speeds up the polymerisation process, and that sulfate ion competes with silicate for surface adsorption sites. Thus, the precipitation of silica proceeds much more rapidly in ferric nitrate media, than in ferric sulfate.

Internal gamma decay and the superallowed branching ratio for the beta(+) emitter (38)K(m).

The branching ratio for the superallowed beta(+) decay of (38)K(m) was measured at TRIUMF's ISAC radioactive ion beam facility. The M3 internal transition between the isomer and the ground state of (38)K(m) was observed with a branching ratio of 330(43) ppm. A search for the nonanalogue beta-decay branch to the first excited 0(+) state in (38)Ar was also performed and yielded an upper limit of < or =12 ppm at 90% C.L. These measurements lead to a revised superallowed branching ratio for (38)K(m) of 99.967(4)%, and increase the (38)K(m) ft value by its entire quoted uncertainty to ft=3052.1(10) s. Implications for tests of the nuclear-structure dependent corrections in superallowed beta decays and the extraction of the Cabibbo-Kobayashi-Maskawa matrix element V(ud) are discussed.

Outpatients' Experience of Quality Service Delivery at a Teaching Hospital in Gauteng

Quality service delivery to the consumer of health is a legal reality as it is emphasised in the White Paper on the Transformation of Public Service delivery (South Africa; 1997). The guiding philosophy adopted within this framework is that of Batho Pele; which means placing the consumer at the centre of healthcare service delivery. Increasing attention has been paid to hospital processes from a quality perspective. By analogy; outpatient departments can be viewed as industrial plants where technological know-how is transferred to patients through service delivery; which is a cornerstone of a hospital's business. Outpatients; as consumers of healthcare; draw conclusions about the quality of service delivery based on their experiences of such services. In this vein; an outpatient's experience of a particular service is an indicator of his/her level of satisfaction with the quality of that service. No South African study can be found in the literature on out-patients' experiences of quality service delivery. This study's purpose is to explore and describe outpatients' experiences of the quality of service delivery at a teaching hospital in Gauteng. A qualitative; explorative; descriptive study that was contextual in nature was conducted to achieve this aim. Focus group interviews were conducted with outpatients who met the selection criteria. Open coding was used to analyse the contents from the transcripts and field notes typed verbatim. Strategies for trustworthiness; namely co-coding; prolonged engagement; triangulation and adequate referencing; were employed to ensure the credibility of the study and research findings. The results reflect themes that were reduced into two main categories; namely positive and negative experiences. The positive experiences reflect outpatients' experience of their relationship with medical staff and their satisfaction with the quality of medical care. Negative experiences relate predominantly to a lack of service commitments; unethical context; and inter-personal relationship difficulties that render them powerless and dehumanised. Recommen- dations are made to improve the quality of service delivery at outpatient departments

Scintigraphy of acute inflammatory lesions in rats with radiolabelled recombinant human neutrophil-activating peptide-2.

Radiolabelled recombinant human interleukin-8 (IL-8) with its homologue neutrophil-activating peptide-2 (NAP-2) have been compared for imaging acute sterile inflammatory lesions in rats. 125I-IL-8 and 125I-NAP-2 were prepared by reaction with chloramine-T and injected intravenously into male rats bearing subcutaneous carrageenan abscesses in their left hindlimbs. Left hindlimb and right hindlimb activities were determined from serial total-body scintigrams between 1 h and 96 h post-injection as regional per cent injected activity corrected for physical decay (%IA). Time-activity curves for 125I-IL-8 and 125I-NAP-2 in the carrageenan-containing left hindlimbs were similar in that both peaked at 1-3 h post-injection (IL-8, 4.9+/-0.5%IA; NAP-2, 4.8+/-1.9%IA) and decreased exponentially thereafter. However, while the lesioned-to-control limb activity ratio (L/C) for 125I-IL-8 only approximately doubled during the imaging period (1.7+/-0.3 at 1 h vs 3.7+/-1.0 at 24 h post-injection), L/C for 125I-NAP-2 more than tripled, rising from 1.5+/-0.4 at 1 h to 5.3+/-0.7 by 72 h post-injection. It is concluded that while both radiolabelled IL-8 and NAP-2 may prove useful for clinical imaging, radiolabelled NAP-2 may provide better discrimination of inflammatory lesions from normal tissue at later times post-injection.

Scintigraphy of acute inflammatory lesions in rats with radiolabelled recombinant human interleukin-8.

We compared 125I-labelled recombinant human interleukin-8 (125I-IL-8) with 111In-labelled human leukocytes (111In-WBC) and 67Ga-citrate for scintigraphic depiction of acute sterile inflammatory lesions in rats. Radioiodination of IL-8 was catalysed by chloramine-T, and human leukocytes were radiolabelled with 111In-oxine. Inflammatory lesions were induced in male rats by subcutaneous injection of 2% carrageenan suspension into their left hindlimbs. Twenty-four hours later, each rat received 1.8-3.7 MBq (50-100 microCi) of a single agent by intravenous injection. Sequential whole-body scintigrams were obtained between 0 and 96 h post-injection. Activities in the lesion-bearing and control hindlimbs were expressed as regional percent injected activity corrected for physical decay (%IA) by reference to concurrently imaged standards, and for 125I-IL-8 by direct tissue counting at necropsy as well. 125I-IL-8 displayed appropriate electrophoretic mobility, retained chemotactic and high-affinity receptor-binding activity in vitro, and exhibited exponentially decreasing activity in most tissues beginning shortly after intravenous injection. Scintigrams showed asymmetrically increased activity in the lesion-bearing hindlimb for all three agents. By scintigraphy, 125I-IL-8 activity in the lesion-bearing hindlimb reached a zenith 1-3 h post-injection at 4.8 +/- 0.5 %IA and decreased exponentially thereafter, with little change in lesioned-to-control limb ratios (mean L/C = 3.0 +/- 0.7) over the imaging period. By direct tissue counting, abscess-associated mean IL-8 activity per gram of tissue increased to four times that of adjacent muscle and nearly seven times that of contralateral muscle by 24 h post-injection. Lesion-bearing hindlimb 111In-WBC activity also rose rapidly, reaching 4.2 +/- 0.6 %IA by scintigraphy at 3 h and an eventual plateau (maximum of 4.5 +/- 0.4 %IA) by 24 h. 67Ga scintigraphic activity in the lesion-bearing hindlimb peaked briefly at 3-6 h post-injection (9.2 +/- 0.5 %IA) and subsequently declined to a constant level of about 7.5 %IA. However, L/C for 111In-WBC and for 67Ga-citrate each averaged only 1.5 +/- 0.3 over the imaging period, compared with a mean L/C of 1.2 +/- 0.2 for a blood pool radiotracer. We conclude that 125I-IL-8 is rapidly and selectively concentrated in regions of acute inflammation, presumably by high-affinity binding to IL-8 receptors on neutrophils within the inflammatory focus. Radioiodinated IL-8 offers an attractive alternative to 67Ga-citrate and 111In-WBC for early imaging of acute inflammatory lesions, and demonstrates significantly higher target-to-nontarget activity ratios in this model. The potential usefulness of radiolabelled IL-8 for clinical scintigraphy should be evaluated.