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Biomedical subjects

Xingming Guo

Publications and source records attributed to Xingming Guo.

5 recordsLinked to original sources
PubMed2005

[Design of multifocal visual electrophysiology examining system based on fast m-transform].

The multifocal visual electrophysiology is an objective and non-invasive method to examine visual function. It can examine many tiny areas of retina at the same time and have a particular advantage in diagnosing the early diseases of ocular fundus. This paper introduces the design of multifocal visual electrophysiology examining system. The system uses multidisplay technology exclusively owned by Windows 98 or above operating system to control graphics stimulator which generates specified hexagonal array. The white or black transition of each hexagon controlled by a binary m-sequence stimulates corresponding area of retina. The specified Burian-Allen electrode is used to extract the mixed signal originated from many areas of retina. The signal is amplified and A/D transformed. The computer separates the mixed signal through fast m-transform and gets the response of each area of retina. The fast m-transform is a fast computation of cross-correlations with binary m-sequences and can reduce cross-correlation computation to a single Fast Walsh Transform. So a lot of time can be saved.

Electrophysiology↗
PubMed2004

[Heart sound recognition algorithm based on mathematical morphology].

In this paper, a new method was put forward for automatic recognition of the first heart sounds (S1) and the second heart sounds (S2). After the original heart sound signal was preprocessed, the heart sound envelope was extracted by using the mathematical morphology. Then on the heart sound envelope, S1 and S2 were recognized. Eighty heart sound samples collected were used for testing the algorithm. The accuracy of recognition was 86%, and was 100% for the normal heart sound. The result showed that the algorithm proposed in this paper had high performance, which could be used as a basis for further analysis of heart sound.

Algorithms↗
PubMed2002

A relative value method for measuring and evaluating cardiac reserve.

BACKGROUND: Although a very close relationship between the amplitude of the first heart sound (S1) and the cardiac contractility have been proven by previous studies, the absolute value of S1 can not be applied for evaluating cardiac contractility. However, we were able to devise some indicators with relative values for evaluating cardiac function. METHODS: Tests were carried out on a varied group of volunteers. Four indicators were devised: (1) the increase of the amplitude of the first heart sound after accomplishing different exercise workloads, with respect to the amplitude of the first heart sound (S1)recorded at rest was defined as cardiac contractility change trend (CCCT). When the subjects completed the entire designed exercise workload (7000 J), the resulting CCCT was defined as CCCT(1); when only 1/4 of the designed exercise workload was completed, the result was defined as CCCT(1/4). (2) The ratio of S1 amplitude to S2 amplitude (S1/S2). (3) The ratio of S1 amplitude at tricuspid valve auscultation area to that at mitral auscultation area T1/M1 (4) the ratio of diastolic to systolic duration (D/S). Data were expressed as mean +/- SD. RESULTS: CCCT(1/4) was 6.36 +/- 3.01 (n = 67), CCCT(1) was 10.36 +/- 4.2 (n = 33), S1/S2 was 1.89 +/- 0.94 (n = 140), T1/M1 was 1.44 +/- 0.99 (n = 144), and D/S was 1.68 +/- 0.27 (n = 172). CONCLUSIONS: Using indicators CCCT(1/4) and CCCT(1) may be beneficial for evaluating cardiac contractility and cardiac reserve mobilization level, S1/S2 for considering the factor for hypotension, T1/M1 for evaluating the right heart load, and D/S for evaluating diastolic cardiac blood perfusion time.

Adolescent↗