Biomedical subjects

Xiao-fei Wang

Publications and source records attributed to Xiao-fei Wang.

7 recordsLinked to original sources

PubMed2006

[The calibration of instrument response function during passive FTIR measurement].

In order to obtain infrared spectral radiance distribution of some infrared sources, such as spectral radiant flux density, spectral radiant intensity, spectral radiance and spectral irradiance, the instrument response function under different conditions must be known. In the present paper, the calibration of instrument response function during passive FTIR measurement has been discussed. The experimental results illustrate that under different experimental conditions, the instrument response function varies not only with the temperature of the blackbody but also with the signal amplitude received by the infrared instrument. So, during passive FTIR measurement, the temperature and the emission signal amplitude of the source must be observed carefully in order to get satisfactory instrument response function.

English Abstract↗

PubMed2006

[Automated recognition of VOCs using artificial neural networks].

Quantitative analysis of FTIR spectra, which are seriously overlapped in the spectral bands, was studied by artificial neural networks. The optimum network was chosen by a new criterion, i. e. the degree of approximation. After the network was established, two kinds of spectra were resolved. It was demonstrated that accurate results could be obtained when two components were both included. In addition, the unknown spectrum could be identified and quantified. It was showed that the artificial neural network has excellent non-linear ability of solution. Meanwhile, the method provides an efficient approach to the identification and quantification of the unknown samples.

English Abstract↗

PubMed2006

[Remote passive detection of flame temperature of solid propellant adulterating nanoparticles].

The flame temperature of three kinds of solid propellants was measured by passive remote sensing FTIR with the resolution of 1 cm(-1). These three kinds of solid propellants are adulterate nano-scale metal oxide particles, adulterate normal metal oxide particles, and propellant without any adulterations. The main components of the solid propellant are nitrocellulose and nitroglycerin. The metallic oxides, including 6 nm CuO, 56 nm Fe2O3, 16 nm NiO, and correspondingly the normal particles, were adulterated into the solid propellants respectively. The flame temperature was calculated through the fine structure of the emission fundamental band of H2O at 2.75 microm. The results of the flame temperature of the solid propellants adulterating nano-scale CuO, Fe2O3 and NiO are 3089, 3193 and 3183 K, respectively. The temperatures of the three kinds of solid propellants were compared, and it was shown that there is no obvious difference in the flame temperature among the three kinds of solid propellants.

English Abstract↗

PubMed2006

[Multi-component analysis of FTIR spectra of non-linear system using polynomial partial least squares method].

A non-linear algorithm, polynomial PLS was applied to the simultaneous analysis of OP-FTIR spectra of a five-component system whose FTIR spectra were seriously overlapped. The results were compared with the one obtained from PLS. PPLS yielded good performance, especially for the prediction of benzene and chloroform. RMSEP (root mean squared error of prediction) of benzene and chloroform in PPLS model were 0.043 and 0.087 and the corresponding values in PLS were 0.402 and 0.842, respectively. Meanwhile, variance was accounted by PPLS with fewer latent variables, which indicates the simplicity and robustness of the model. The successful application of PPLS to non-linear system was meaningful for the use of remote sensing FTIR in air monitoring.

English Abstract↗

PubMed2005

[Intravascular ultrasound study of coronary remodeling and determination of matrix metalloproteinase and hypersensitive C-reactive protein].

OBJECTIVE: To investigate remodeling characteristics of coronary lesions in patients with acute coronary syndromes (ACS) versus stable angina pectoris (SA) using intravascular ultrasound (IVUS), and to explore the relationship between arterial remodeling and clinical presentation or matrix metalloproteinase (MMPs) or hyper-sensitive C-reactive protein (hs-CRP). METHODS: We studied culprit lesions of 38 patients with ACS and 18 patients with SA using IVUS before coronary intervention. The lesion site and a proximal or distal reference site including the external elastic membrane (EEM) area and lumen area were analyzed. Plaque area and remodeling index (RI) were calculated, and directions of arterial remodeling were determined. Positive remodeling was defined as RI > 1.05 and negative remodeling as RI < 0.95. We analyzed the culprit lesion qualitatively, identified high risk plaque and compared them in each group. The blood level of MMP-2, MMP-9 and hs-CRP in each group were also determined. RESULTS: The plaque area at culprit lesions in patients with ACS was significantly larger (11.94 +/- 4.90 versus 9.17 +/- 3.36 mm2; P = 0.035), and also the RI in ACS group was significantly greater than that of patients with SA (0.972 +/- 0.222 versus 0.796 +/- 0.130; P = 0.003). The distribution of remodeling in these two groups was different: positive remodeling was more frequent in ACS group than in SA group (34.2% versus 5.6%, P = 0.047), whereas negative remodeling was more frequent in SA group (52.6% versus 88.9%, P = 0.003). There was higher incidence of high risk plaque in ACS group compared to SA (76.3% versus 50.0%, P = 0.040). The level of serum MMP-2 in ACS group was higher than that of SA group (250.65 +/- 47.97 microg/L versus 214.21 +/- 47.20 microg/L, P = 0.029). The same applied for plasma MMP-9 (84.26 +/- 9.78 microg/L versus 68.46 +/- 22.82 microg/L, P = 0.038) and serum hs-CRP (3.62 +/- 3.37 mg/L versus 1.48 +/- 1.52 mg/L, P = 0.041). CONCLUSIONS: Positive remodeling, larger plaque area and higher incidence of high risk plaque are associated with ACS, whereas negative remodeling is more common in patients with SA. This association between the extent of remodeling and clinical presentation may reflect a greater tendency that plaques with positive remodeling can cause ACS. The change of level of MMP-2, MMP-9 and hs-CRP in ACS patients may be helpful in investigating vulnerable plaques.

Adult↗

PubMed2005

[Application and improvement of partial-least-squares in Fourier transform infrared spectroscopy].

Partial least squares(PLS) algorithm is an effective chemometric tool. It takes the advantages of multipal linear regression (MLR) and principal component regression (PCR), which makes Fourier transform infrared spectrometry (FTIR) more powerful and useful. Accompanied with increasing use of FTIR, the algorithm is modified and corrected under different circumstances. The applications of PLS to FTIR were mentioned. Improved algorithms were presented, such as moving windows PLS(MWPLS), robust PLS (RPLS), weighted PLS(WPLS), and non-linear PLS. Data pre-processing, selection of variable, noise elimination and non-linear model of PLS were introduced.

English Abstract↗

PubMed2005

[Advances in passive OP-FTIR].

As an OP-FTIR(Open Path FTIR) technology, passive OP-FTIR not only has the advantages of OP-FTIR, but also has the ability to collect data from any direction without prior background information. This technology allows mobile, fast, man-held and stand-off detection of hazardous chemical cloud.The present paper presents some developments of passive OP-FTIR, including high altitude atmospheric pollution detection, auto-detection of toxic cloud, hot gases detection (such as the determination of major combustion products in aircraft exhausts, remote sensing of smoke plumes, and remote sensing of volcano emissions), temperature and combustion products determination (including cloud temperature determination). The present paper also gives the application of passive OP-FTIR in the military. With the development of FTIR and computer science, more and more applications of OP-FTIR to environment supervision, aviation and space flight, engine exhausts, combustion and military will be fulfilled.

English Abstract↗