Development of a Fast, Sensitive and Robust LC-MS/MS Method for the Analysis of Natamycin in Wine

Natamycin is a naturally occurring antifungal agent used to inhibit the growth of moulds and yeasts.Characteristics such as low effective concentrations, broad applicability and neutral flavour impact make thiscompound an ideal preservative. Although widely used in the global food industry, natamycin is forbidden inwine in the European Union (EU). It is a permitted wine additive in South Africa, although export wines mustcomply with EU standards. Germany in particular implemented strict measures to prevent wines containingnatamycin from entering their market. Sensitive analytical methodologies with the capacity to regulate thissegment of the wine export industry are therefore required. Here we report on the development of a simple,robust and fast liquid chromatography-electrospray ionisation tandem mass spectrometric (LC-ESI-MS/MS)method for the determination of natamycin in wine. Sample cleanup involves dilution followed by direct elutionof natamycin from aminopropyl SPE cartridges. Recoveries are better than 80% relative standard deviation(RSD < 10%), while the limit of detection (LOD) of the method is 0.0003 mg/L, which renders it compliantwith EU standards. The method also yields qualitative information for positive compound identification. Thedegradation of natamycin in wine was also studied and kinetic parameters are reported in this matrix for thefirst time. The activation energy for the decomposition reaction is ~80 kJ/mol and the half-life under normalwine storage conditions is in the order of 20 days. As in the wine matrix, natamycin in aqueous calibrationstandards are labile, necessitating regular preparation and cold storage of standard solutions to ensure accuratequantitation

A comparison of simple low-power wedge-type X-band waveguide absorbing load implementations

The original publication is available at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4401506Stander, T., Van der Walt, P.W. & Meyer, P. 2007. A comparison of simple low-power wedge-type X-band waveguide absorbing load implementations, AFRICON 2007, Windhoek, September 26-28, doi:10.1109/AFRCON.2007.4401506.Two inexpensive waveguide absorbing loads are constructed and measured, each using a single thin resistive sheet absorber supported by styrofoam walls, and 50mm in length. It is found that a V-cut wedge displays less reflection than a tapered wedge, with -30 dB reflection across a band 8.5 - 12.4 GHz.Post-prin

Cost-effectiveness analysis of human papillomavirus vaccination in South Africa accounting for human immunodeficiency virus prevalence

Input ranges for one way sensitivity analyses. (PDF 156 kb

Application of Time Domain Reflectometers in Urban Settings

Time domain reflectometers (TDRs) are in-situ monitoring probes that record soil moisture content when calibrated to a particular soil. Typically TDRs are used in agricultural settings, but this technology may also be applied to urban soils. The Urban Watershed Management Branch located at the Edison Environmental Center (EEC) has been exploring the use of TDRs as a way to monitor stormwater infiltration practices. TDRs are installed in pilot- and full-scale bioretention units (e.g., rain gardens). The TDRs are capable of measuring soil moisture and sensing the wetting front as the stormwater infiltrates through the planting media and into the native soil. Recently, a new permeable pavement parking lot was constructed at the EEC. This parking lot was designed for long-term monitoring and included the installation of TDRs, both in the crushed concrete storage layer and in the underlying soil. Early indications suggest that while this novel application of TDRs in crushed concrete may not provide calibrated moisture content, wetting fronts correspond to those of the TDRs in soils. Extensive bench-scale testing was performed in crushed concrete prior to the permanent installation below the paved surfaces as a proof of concept test. Application of this technology may be suitable to urban areas that are interested in modifying tree pit design, controlling stormwater through rain gardens and porous pavements, or using manufactured or engineered soils, and seek or require supporting data that water is infiltrating and available to plants

Oral medicine case book 47: oral neurofibroma

A 29-year-old male patient presented at the Oral Medicine Clinic with the complaint of slow-growing growths on his tongue, causing discomfort. Extra-oral examination revealed several painless soft tissue nodules on his face (Figure 1 and 2), trunk (Figure 3), back (Figure 4) and arms. The patient reported that the lesions had appeared during childhood and had since increased in size and number. He was unaware of any family history of the disease. Intra-oral examination showed two soft tissue nodules on the midline of the dorsal surface of the tongue, 3,5cm and 0,5 cm in diameter respectively (Figure 5).Department of HE and Training approved lis

Oral medicine case book 46: squamous cell carcinoma of the tongue

A 38-year-old-female presented at the Oral Medicine Clinic complaining of pain under her tongue that became worse during chewing, and radiated to her right ear. The pain started two months earlier and gradually increased in intensity. The patient reported that she smoked about twelve cigarettes per day, a habit that she maintained for the last twenty years. She also admitted that she consumed alcohol as a social habit, mainly over the weekends. Her medical history revealed no other abnormalities and she was not using any chronic medication.Department of HE and Training approved lis

Utilisation of outpatient services at Red Cross War Memorial Children's Hospital, Cape Town

The demand for outpatient services continues to grow at Red Cross War Memorial Children's Hospital (RCCH). To determine current utilisation patterns, we conducted a 2-week survey in the outpatient department (OPD). In addition, we reviewed the RCCH Annual Reports for the period 1961 - 1988. Annual outpatient attendances have increased from around 42000 in 1957 to their highest level ever; nearly 350000 in 1988. This steady rise in outpatient attendance was stemmed during the 1970s by the expansion of health services in the greater Cape Town area, in particular the introduction ofday hospitals. In general, blacks are utilising the OPD as a primary community hospital for the treatment of infectious and environmentally induced diseases. In contrast, the white outpatient profile is more characteristic of a tertiary referral centre, with a higher proportion of specialist clinic attendances. The utilisation patterns for coloured children are intermediate. Analysis of the residential address of patients and their presenting diagnoses indicates an urgent demand for primary health care services in the most recently settled and poorest suburbs of Cape Town, many of which are remote from the hospital