The effects of mm-waves 60.22-62.22 GHz and 75 GHz on A-type K+ currents and the effects of 61.22 GHz on Ca2+ currents of Lymnaea neurons were investigated using a whole-cell voltage-clamp technique. The open end of a rectangular waveguide covered with a thin Teflon film served as a radiator. Specific absorption rates at the waveguide outlet, inserted into physiological solution, were in the range of 0-2400 W/kg. Millimeter wave irradiation increased the peak amplitudes, activation rates, and inactivation rates of both ion currents. The changes in A-type K+ current were not dependent on the irradiation frequency. It was shown that the changes in the amplitudes and kinetics of both currents resulted from the temperature rise produced by irradiation. No additional effects of irradiation on A-type K+ current other than thermal were found when tested at the phase transition temperature or in the presence of ethanol. Ethanol reduced the thermal effect of irradiation. Millimeter waves had no effect on the steady-state activation and inactivation curves, suggesting that the membrane surface charge and binding of calcium ions to the membrane in the area of channel locations did not change.

This manuscript was written to bring together the pertinent statistical procedures for specifying acoustic output values and measurement uncertainties of ultrasound devices, and to present them in a way that would be clear and convenient to the reader. Implementations of these procedures are illustrated in several examples: measurement of ultrasonic power of a single transducer, measurement of the power output of a transducer model, and measurement of the power output of an ultrasound scanner series. This manuscript is intended to be helpful to ultrasound device manufacturers who need to specify these quantities when applying for Food and Drug Administration (FDA) approval to market their new devices. It also is intended to be helpful to ultrasound users who need to interpret these values in order to meaningfully evaluate the relative risks and benefits of performing ultrasound examinations on their patients.

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Conventional televised fluoroscopy enables real-time visualization of dynamically changing structures within the body provided there is adequate radiologic contrast between the object of interest and its immediate surround. Under special conditions, such as in arteriography, injection of a contrast agent into the structure being studied enhances its visualization. Where applicable, greatest contrast enhancement is provided by image subtraction. In our experience, because of the intrinsic noisiness of television (TV), radiologic contrast had to exceed 5 percent for visualization by any of the aforementioned techniques. In order to measure a 1 percent X-ray transmission variation, we have replaced the vidicon camera with a Reticon solid-state matrix camera. This camera contains a 32 by 32 photodiode array with an intrinsic noise level far below that of standard TV. However, a fixed-pattern pixel noise due to differing pixel sensitivities must be canceled out. This is easily performed by subtraction with a dark-field pixel pattern previously stored in a computer. The frame rate of the camera can be varied from 15 to 100 Hz. The video signal is digitized and entered into a LINC-8 digital computer for densitometry. The primary use of this system to date has been in the measurement of pulmonary pulsations in monkeys. These pulmonary pulsations are small variations in X-ray transmission through the chest due to the change in blood content of the lungs during each heartbeat. A decrease in the amplitude of pulmonary pulsations is a potentially important diagnostic sign in the clinical evaluation of cardiac failure and in early lung cancer.