A method for allocating an AcknowledgementNegative Acknowledgement channel by a Base Station in a Frequency Division Duplexing system is provided. Preferably, the 1,3-propanediol comprises about 100 microgg or less of monofunctional alcohol compounds based on the weight of the PDO. The discharge vessel has a ceramic wall and is closed by a ceramic plug. A magnetic field can alternatively be applied around the transmitter, receiver and sample to enhance some characteristic analysis applications.