PURPOSE To compare the sensitivity of conventional spin-echo, fast spin-echo, fast fluid-attenuated inversion recovery (FLAIR), and turbo gradient spin-echo MR sequences in the detection of multiple sclerosis lesions. METHODS Conventional spin-echo, fast spin-echo, fast FLAIR, and turbo gradient spin-echo sequences were performed on a 1.0-T MR imager in seven patients with clinically definite...

The main purpose of the study is determination of the pollutants hazard potential as well as environmental vulnerability of Qarah Su River. First the most significant pollutant sources in the Qarah Su river watershed were identified and then accordingly the pollution hazard potential rate was calculated in Universal Ranking System Model setting. Then, by generalizing the algebraic sum of the re...

the main purpose of the study is determination of the pollutants hazard potential as well as environmental vulnerability of qarah su river. first the most significant pollutant sources in the qarah su river watershed were identified and then accordingly the pollution hazard potential rate was calculated in universal ranking system model setting. then, by generalizing the algebraic sum of the re...

Pollutant chemicals that are widespread in the environment can affect endocrine function in laboratory experiments and in wildlife. Although human beings are commonly exposed to such pollutant chemicals, the exposures are generally low and clear effects on endocrine function from such exposures have been difficult to demonstrate. Human data including both exposure to the chemical agent and the ...

This paper presents evaluations of a nonlinear-echo suppressor based on a frequency-domain model of highly nonlinear residual echo. The residual-echo model, which is based on correlation between spectral amplitudes of residual echo and echo replica, is evaluated by a regression analysis. The results justify the nonlinear-echo suppressor structure. The output signals are subjectively evaluated b...

Acoustic echo arises due to acoustic coupling between the loudspeaker and the microphone of a communication device. Acoustic echo cancellation and suppression techniques are used to reduce the acoustic echo. In this work we propose to first cancel the early echo, which is related to the early part of the echo path, and subsequently suppress the late echo, which is related to the later part of t...

PURPOSE To compare lesion enhancement after injection of gadopentetate dimeglumine on spin-echo and gradient-echo T1-weighted images. METHODS A total of 48 contrast-enhancing intracranial lesions were evaluated using a spin-echo and two gradient-echo T1-weighted pulse sequences. Percent contrast, contrast-to-noise, and signal-to-noise measurements were made on the spin-echo T1-weighted, three...

Acoustic echoes arise whenever there is acoustic coupling between a loudspeaker and a microphone. A traditional solution for eliminating the undesired echo signal is an acoustic echo canceler (AEC), which identifies the echo path between a loudspeaker and a microphone by means of an adaptive filter. The echo signal can be canceled successfully when the modeling filter approaches the true echo p...