Subacute carbon monoxide poisoning presenting as vertigo and fluctuating low frequency hearing loss.

It is estimated that up to 25 000 UK residents are exposed to small amounts of carbon monoxide (CO) annually. Symptoms of chronic exposure to CO are vague and non-specific and include dizziness and hearing loss. We describe a case of 38-year-old lady presenting with a 4-month history of vertigo and hearing loss. Initially diagnosed as Meniere's disease, the patient was investigated and followed up in the clinic. She reported leakage of carbon monoxide from her gas fire identified during a routine safety check. Her symptoms fully resolved after disconnecting the faulty gas fire. A rare cause of fluctuating hearing loss and vertigo is described, and the diagnostic challenges are discussed

Development of PZT Actuated Valveless Micropump

A piezoelectrically actuated valveless micropump has been designed and developed. The principle components of this system are piezoelectrically actuated (PZT) metal diaphragms and a complete fluid flow system. The design of this pump mainly focuses on a cross junction, which is generated by a nozzle jet attached to a pump chamber and the intersection of two inlet channels and an outlet channel respectively. During each PZT diaphragm vibration cycle, the junction connecting the inlet and outlet channels with the nozzle jet permits consistencies in fluidic momentum and resistances in order to facilitate complete fluidic path throughout the system, in the absence of any physical valves. The entire micropump structure is fabricated as a plate-by-plate element of polymethyl methacrylate (PMMA) sheets and sandwiched to get required fluidic network as well as the overall device. In order to identify the flow characteristics, and to validate the test results with numerical simulation data, FEM analysis using ANSYS was carried out and an eigenfrequency analysis was performed to the PZT diaphragm using COMSOL Multiphysics. In addition, the control system of the pump was designed and developed to change the applied frequency to the piezoelectric diaphragms. The experimental data revealed that the maximum flow rate is 31.15 mL/min at a frequency of 100 Hz. Our proposed design is not only for a specific application but also useful in a wide range of biomedical applications