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Oestrus ovis or 'sheep botfly' causes common ophthalmomyiasis in warm climates. It is a self-limited infestation with symptoms such as foreign body sensation and/or tearing. The larvae can be observed in the conjunctiva and should be extracted with forceps. The development of larvae beyond the first stage does not occur in healthy humans, although they may penetrate the ocular globe, causing so-called internal myiasis. External ophthalmomyiasis is typical of rural areas, but it may be observed occasionally in urban environments.

Large scale cadmium sulfide nanoparticles were synthesized by simple chemical route. The microstructure of cadmium sulfide nanoparticles was characterized by X-ray diffraction pattern (XRD) FESEM, FTIR and UV-visible spectroscopy. The XRD results showed that there was a transformation from cubic to hexagonal crystalline phase. The W-H plots show the size and nature of the strain incorporated in peak broadening of X-ray diffraction peaks. Some of the observed peak broadening can be attributed to crystallite size and microstrain effects, dislocation density, hkldependent peak broadening and peak shifts are clearly associated with stacking faults. The refractive index of the CdS nanoparticles was estimated to 2.22. The optical band gap of the synthesized CdS nanoparticles was calculated by Tauc relation and found to be 3.45 eV. The dependence of the blue shift and optical band gap on the quantum size effect was confirmed by UV-Visible spectroscopy. FTIR study confirmedthat the-CO and-OH groups of thioglycerol can readily bind with CdS nanoparticles.

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The work presented here is part of an overall design system with a silicon based ponent for the determination of copper, zinc. Voltammetric (the measurement tion of potential) methods of analysis are attractive for determinations of trace metals. They offer a combination of simple low cost instrumentation with excellent sensitivity and detection limits, comparable to those obtainable with instruments costing orders of magnitude greater. The system consists of (ASIC) and software control. There is increasing pressure on industry and regulatory bodies to monitor industrial and domestic pollution. A particular concern is the c o n~i n a t i o n of water supplies with heavy metals. The aim of this work is to develop a method of heavy s using a device that can be manufactured at are compatible with microelectronics processes giving a low cost solution to trace metal analyses for water quality applications. been designed with areas ranging from 0.2 mm2 to 3.75 mm2 compatible with reproducible area screen printing.electrodes, an application specific integrated circuit ASILTH Figure I : System Overview.The elements of the measurement system are illustrated in Figure 1. It comprises a disposable "Dipstick" rporating a sensor ASIC (ASICTH), a "System ' incorporating a measurement ASIC (ASICM), and a notebook PC AT compatible. The system is operated by connecting a "dipstick" to the "System Pod" and ing a drop of the analyte to be analysed to the tick". The presence of the sample is sensed and the starts a~~omatical~y. Electrodes have been fabricated by combining silicon fabrica~on and screen printing technologies. Platinum is deposited and patterned on a thermally oxidised silicon substrate. Titanium is used as an adhesion layer between the p~a t~u m and the oxide. A three electrode system is then realised by screen printing carbon onto two of the platinum electrodes to form the working and counter es. Silver/silver chloride (Ag/AgCI) is screen printed onto the third area of platinum to form a reference electrode. Both disc and band electrodes have Figure 2: Prototype design of electrodes made by screen-printing carbon and SilverlSilver Chloride inks onto a silicon wafer . 948 TRANSDUCERS '95 .