Radiation protection at the National Nuclear Research Centre, Pelindaba

No Abstrac

Placental localization and assessment of foetal whole bodyand gonadal radiation following R131ISA placentography

Accurate localization of the placenta is rapidly becoming of the utmost importance in the modern practice of obstetrics. In the diagnosis and treatment of placenta praevia and the performance of amniocentesis, knowledge as to the site of placental insertion is imperative. Furthermore, the situation of the placenta plays a definite role in labour and delivery

Factors affecting pregnancy outcome in a gamete intrafallopian transfer (GIFT) programme

Objective. To identify the factors that most significantly affected pregnancy rates in a gamete intrafallopian transfer (GIFT) programme.Methods. A total of 863 GIFT cycles were analysed retrospectively. The variables found to be associated significantly with pregnancy were then used to obtain multivariate analysis using logistical regression.Results. Overall and ongoing pregnancy rates were significantly better in patients ≤ 38 years than in patients > 38 years (37.3% and 28.4% v. 23.7% and 11.0% respectively), and age was positively associated with success after GIFT (odds ratio (OR) 1.87, 95% confidence interval (CI): 1.22- 2.85). Metaphase I (MI) oocytes were negatively associated with pregnancy (OR 1.54, 95% CI: 0.28 - 1.04). The highest pregnancy rates occurred when 3 metaphase II (MII) oocytes were transferred (39.8%, OR 7.51, 95% CI: 1.74 - 32.42). With regard to sperm morphology, overall pregnancy rates of 25.5% (≤ 4% normal forms) and 37.2% (> 4% normal forms) were obtained. Morphology of > 4% normal forms was positively associated with pregnancy (OR 1.58, 95% CI: 1.04 - 2.42).Conclusion. The results of this study suggest that the most important factors influencing pregnancy rates in a GIFT programme are the woman's age and those factors pertaining to the characteristics of the gametes. Considering the emotional and financial costs it is important to relate this information to all prospective participants in a GIFT programme

Quality deterioration and loss of shelf life as a result of poor road conditions

Postharvest science focuses mainly on the quality of fresh produce. One of the areas of interest is the shipment of tomatoes using road transport. Because tomatoes have a limited shelf life, it is vital to control the factors that lead to early deterioration of the quality of the product. Logistical operations can cause numerous forms of cuts and bruises on harvested tomatoes which compromise their quality and appearance. For this experiment, the in-transit conditions were monitored on trucks shipping tomatoes from three farms in Limpopo, South Africa to the fresh produce market in Pietermaritzburg. This research attempts to create a model that relates tomato damage and loss in shelf life to the road condition, fruit ripeness and position in the container. With this information in hand, logistic planners can make informed decisions during route planning. Transportation cost can be weighed against the cost of losses of produce during transportation. Similar models can be developed to include other types of fruits and vegetables.https://www.inderscience.com/jhome.php?jcode=ijptiam2020Civil Engineerin

Influence of road roughness on the transportation of fresh produce

Paper presented at the 31st Annual Southern African Transport Conference 9-12 July 2012 "Getting Southern Africa to Work", CSIR International Convention Centre, Pretoria, South Africa.The agricultural sector is one of the largest economic sectors in South Africa. Damage to fresh produce during transportation and handling decreases the value of the products of this sector and it increases logistics costs. Bad road conditions cause more damage to produce and it increases the maintenance cost of vehicles used to transport produce from growers to distributors. Perishable commodities such as fruits and vegetables are sensitive to a variety of factors including temperature, atmospheric gasses and vibrations induced during transportation. All of these factors affect the quality of the fresh produce that reaches the consumer. This paper focuses on damage to fresh produce caused as a result of exposure to different vibrations during transportation. As the riding quality of roads deteriorates more vibrations are experienced and the possibility of damage to produce is increased. Vibrations induced during transportation of produce on different road conditions are evaluated. It is expected that more vibrations would be induced on gravel roads than national and provincial roads in the Limpopo province of South Africa.This paper was transferred from the original CD ROM created for this conference. The material was published using Adobe Acrobat 10.1.0 Technology. The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: nigel@doctech URL: http://www.doctech.co.zadm201

Boekbespreking

No abstract available

A Review of Interventions to Reduce Mechanical Restraint and Seclusion among Adult Psychiatric Inpatients

Objective: This review examines nature and effectiveness of interventions to reduce the use of mechanical restraint and seclusion among adult psychiatric inpatients. Method: Electronic searches were conducted to locate post-1960 empirical studies of restraint and seclusion reduction in English. A total of 36 studies were identified, mostly from the USA. Analysis was conducted using a structured data extraction tool. Results: The majority of studies reported reduced levels or mechanical restraint and/or seclusion, but the standard of evidence was poor. There were no randomised trials. Most were retrospective studies of official records before and after the intervention was introduced, with varying follow-up periods. The interventions were diverse, but tended to include one or more of the following: new restraint and/or seclusion policies, staffing changes, staff training, review procedures and crisis management initiatives. The research was unable to address which of these elements was most effective. There was also evidence that some improved outcomes were achieved by substituting restraint or seclusion for each other or for alternatives forms of containment (medication in particular). Nurses’ attitudes, skills and approach to patient care were absent from the literature. Conclusions: Interventions probably can reduce the use of restraint and seclusion, but better designed research is required to demonstrate their effectiveness conclusively. More attention should also be paid to understanding how interventions work, particularly from the perspective of nursing staff. This is essential to the successful implementation of restraint and seclusion interventions across different psychiatric settings and treatment populations

Improvement of the pharmaceutical availability and membrane permeability of furosemide by formulation design

PhD (Pharmaceutics), North-West University, Potchefstroom CampusFurosemide is a well-known loop diuretic having weak acidic chemical properties. Furosemide belongs to the Biopharmaceutical Classification System (BCS) class IV because it has poor aqueous solubility and poor membrane permeability characteristics. In this study, the effect of different combinations of functional excipients (i.e. chitosan, sodium lauryl sulphate, NaHCO3 and CaCO3) in the formulation of multiple-unit pellet system (MUPS) tablets has been investigated. Spherical beads (0.5 mm, 0.75 mm and 1 mm) were produced by extrusion-spheronisation consisting of different combinations of excipients, which were compressed to form flat faced, bevelled edge MUPS tablets. Three control MUPS tablet formulations (i.e. containing 0.5 mm, 0.75mm and 1 mm beads) were prepared without the functional excipients. A commercial product (Lasix®) was also included in the study as a reference for purposes of comparison. Each MUPS tablet formulation was evaluated for physical properties (hardness, disintegration, mass variation and friability), whereasthe bead formulations were tested for mucoadhesiveness. Dissolution evaluations were conducted on each MUPS tablet formulation in media with three different pH environments, namely 0.1 M HCl (pH 1.2), citric acid buffer (pH 4.6) and a phosphate buffer (pH 7.4). Ex-vivo permeability studies were performed across excised pig tissues of the pyloric antrum and the duodenal region on selected experimental MUPS tablet formulations; the control MUPS tablet formulations, and (or as well as) the commercial product. Histological analysis was conducted on the tissues after exposure to the selected experimental MUPS tablet formulations, the control MUPS tablet formulation and the commercial product. The dissolution results in the 0.1 M HCl (pH 1.2) showed the highest effect of the excipients on furosemide release when compared to the control formulations and the commercial product. This phenomenon was expected due to the acidic nature of furosemide. All the dissolution parameters showed increased dissolution of furosemide for the MUPS tablet formulations containing the functional excipients as compared to that of the control MUPS tablet formulations as follow: the AUC values of the dissolution curves showed a 4.5–10 fold increase, the %max showed a 60–70% increase and the DRi exhibited up to a 19 fold increase. Permeability results revealed the selected MUPS tablet formulations had a 2.5 fold higher cumulative percentage transport than the control MUPS tablet formulation without a cytotoxic effect on the tissues. The results from this study showed that the combination of selected functional excipients incorporated into beads that were compressed into MUPS tablet formulations not only increased furosemide release, but also its permeation across excised intestinal tissues.Doctora

Hierarchical bayes analysis of the simplest case-crossover design

In the simplest form of a case-crossover design, the relative risk of an event (such as death) under two different 'exposures' is assessed. The exposure is observed only twice, once at the time of the event. The probability of exposure is required for each individual in the study. These probabilities are traditionally estimated using historical data. The traditional approach yields probabilities of 0, 1/2, and 1 only. A hierarchical Bayesian model is used to obtain more realistic estimates of these probabilities and consequently of the relative risk. Differences between the conventional and Bayes results are exhibited in specific examples.Articl