ABSTRACT
Objective To develop a high-speed data acquisition system for very high frequency medical ultrasonic echo signals. Methods The chip LTC2285 with two integrated ADC channels was adopted to realize analog-to-digital conversion of ultrasonic echo signals. The sampling rate was 120 MHz. The converted digital signals were then input to the FPGA to realize parallel to serial conversion, and high-speed digital signals with a sampling rate of 240 MHz were obtained. Finally, the data were transferred through USB interface to the computer terminal to display. Results A timing simulation experiment, a resolution detection experiment, and an in vivo experiment of normal human eyes were carried out in this system. A preferable simulation result and real-time image were obtained. Conclusion The multi-channel and FPGA technology are used in the design of the system. Lastly, this technology simplifies the overall design of the system and improves the speed and reliability of the high speed data acquisition system.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the T lymphocyte subgroups and the levels of serum zinc (Zn), selenium (Se), iron (Fe), copper (Cu) in patients with diarrhea type of irritable bowel syndrome (D-IBS).</p><p><b>METHODS</b>A total of 30 D-IBS patients and 30 control subjects were enrolled in this study, and their peripheral blood samples were collected. The percentage of peripheral CD3, CD4, CD8 T lymphocytes were analyzed by flow cytometry, and the ratio of CD4/CD8 was calculated. Serum Zn, Fe and Cu levels were determined by atomic absorption spectrometry(AAS), and the Se level by atomic fluorometry.</p><p><b>RESULT</b>Compared with control group,the percentage of CD4 T lymphocyte and the ratio of CD4/CD8 in D-IBS group were significantly lower (P<0.01). However, there was no significant difference in serum Zn, Se, Fe, Cu levels between two groups (P>0.05).</p><p><b>CONCLUSION</b>The declines of peripheral blood CD4 T lymphocytes and the ratio of CD4/CD8 may suggest a cellular immune abnormality in D-IBS patients. There was no significant difference in trace elements levels between the two groups.</p>