Comparison of coronary plaque, coronary artery calcification and major adverse cardiac events in Chinese outpatients with and without type 2 diabetes.

OBJECTIVE: Diabetes substantially increases the risk of cardiovascular disease (CAD) and is associated with an increased risk of CAD mortality. The purpose of this study was to investigate the differences in coronary artery plaque, coronary artery calcification (CAC) measured in outpatients with and without type 2 diabetes, and the occurrence rate of a major adverse cardiac event (MACE) throughout follow-up with the same patients. METHODS: Five hundred eighty-eight outpatients with suspected CAD comprising 208 diabetic and 380 non-diabetic patients were enrolled in this study. Coronary artery plaque and CAC scores were detected and measured by dual-source computed tomography. The major MACE during the follow-up period (4.0-20 months) was recorded and its relationship to type 2 diabetes and CAC was investigated. RESULTS: The diabetes group had higher CAC scores in the left anterior descending, left circumflex, and right coronary arteries and total CAC burden than the group without diabetes. The diabetes group had more diseased coronary segments and more obstructed vessels than the non-diabetes group. Logistic regression analysis demonstrated that diabetes is positively associated with mixed coronary plaque and non-calcified plaque. All patients in the diabetes group and all patients with higher CACs in both groups had a higher incidence rate of MACEs. CONCLUSION: Patients with type 2 diabetes have a higher prevalence of obstructive CAD, higher CAC scores, and a higher incidence rate of MACEs than those without diabetes. Diabetes and higher CAC scores were the important predictors of the occurrence of MACEs throughout follow-up with patients.

High sensitivity and resolution integrated optical system for portable Raman spectrometer.

An integrated optical system with high sensitivity and resolution was presented. This was made possible by coupling a probe to a monochromator directly, using an aspheric lens and an achromatic lens in the coupling path, using a dichroic filter with high transmission and a steep transitional zone as a beam splitter, increasing the throughput of the monochromator, and optimizing its structural parameters. This optical system has a high sensitivity; the tested spectrogram of a glass rod demonstrated that the signal-to-noise ratio measured by the integrated optical system was almost 4 times as high as an independent probe and monochromator. The optical system also has the advantages of high resolution (4 cm-1 or 0.28 nm), low cost, and portable size. This work lays a good groundwork for the development of a high sensitivity, high resolution, and low cost integrated portable Raman spectrometer.

[Baseline Correction Algorithm for Raman Spectroscopy Based on Non-Uniform B-Spline].

As one of the necessary steps for data processing of Raman spectroscopy, baseline correction is commonly used to eliminate the interference of fluorescence spectra. The traditional baseline correction algorithm based on polynomial fitting is simple and easy to implement, but its flexibility is poor due to the uncertain fitting order. In this paper, instead of using polynomial fitting, non-uniform B-spline is proposed to overcome the shortcomings of the traditional method. Based on the advantages of the traditional algorithm, the node vector of non-uniform B-spline is fixed adaptively using the peak position of the original Raman spectrum, and then the baseline is fitted with the fixed order. In order to verify this algorithm, the Raman spectra of parathion-methyl and colza oil are detected and their baselines are corrected using this algorithm, the result is made comparison with two other baseline correction algorithms. The experimental results show that the effect of baseline correction is improved by using this algorithm with a fixed fitting order and less parameters, and there is no over or under fitting phenomenon. Therefore, non-uniform B-spline is proved to be an effective baseline correction algorithm of Raman spectroscopy.

[Design of Raman Spectroscopy Rapid Detection System for Synthetic Edible Pigment Based on PERS].

Based on Plasmon-enhanced Raman Spectroscopy (PERS) technology, the detection system for rapid field determination of synthetic edible pigments in food，such as beverage，meat productsand preserves，is presented. The hardware framework of this detection system is mainly composed of double central control chips (ARM and FPGA), a sample pretreatment module (containing a nanoparticle giving device), a laser diode source, and a spectral data acquisitioning module; Besides, the software can run the sample pretreatment module automatically while receiving the Raman spectrogram. To verify its performance in edible synthetic pigments, the rapid detection system was applied to determine carmine, citrine, allure red in three actual samples (i.e. preserves, sodas, sausage). The relative standard deviations of the sample detection were in the range of ±5%, which indicated that the system developed in this paper have the advantage of favorable sensitivity, excellent repeatability and short testing time. Thus, it meets the requirements for rapid field determination of synthetic pigments in food.

[Research of the Raman Signal De-Noising Method Based on Feature Extraction].

To improve time resolution of the Raman measurement system, we need to adopt short scanning time. In this case, the weak Raman signal with vibrational spectrum of the molecular structure is easily to be buried by the high background noise, which influences the further analysis seriously. So it is necessary to de-noise the raw Raman signals. Conventional methods manage to de-noise signal by means of smoothing or averaging based on the difference between signal and noise in frequency characteristic or statistical features. They are commonly applied in the situation where the background noise is not so strong, and cannot give satisfactory results to the Raman signals with low signal-to-noise ratio. In this paper, the algorithm proposed detects peak positions and get peak half-width based on wavelet transform, and then reconstructs the Raman signals by least square fitting algorithm with characteristic parameters obtained, which extracts the useful signal from high background noise efficiently. In the simulation, the Raman curve fitted by the proposed algorithm was smooth, and the peak positions obtained were accurate, so the signal-to-noise ratio improved significantly. In the experiment, we adopted this algorithm to de-noise the tested Raman signal of Cefuroxime Axetil Tablets and Roxithromycin, respectively. The peak positions, peak half-width and amplitude were obtained and proved to be accurate. Therefore, the useful pure Raman signal could be recovered from the high background noise efficiently by the proposed algorithm, which improved the time resolution of Raman system. Both the simulation and the experiment showed that the proposed method could be easily performed with only a few parameters. Comparing with conventional methods, it could achieve satisfactory results under high background noise and provide accurate and reliable information for further analysis.

General study of asymmetrical crossed Czerny-Turner spectrometer.

A study of the spectrum resolution, wavelength range, and primary aberration of the asymmetrical crossed Czerny-Turner spectrometer is presented by deducing the relationship between them and structural parameters of the spectrometer in a new way of thinking based on simple but effective geometric models. The analysis was verified in an experiment and simulation performed on the optical design program ZEMAX, and the obtained results agree with the analysis. Owing to the analysis, initial designed parameters of the spectrometer were given and then optimized by ZEMAX; with the instruction of the study, a small adjustment was made in the actual alignment to obtain the desired final spectrometer. The spectrometer successfully measured the last four characteristic peaks of the Raman spectrum of CCL4, which demonstrates that the research provides important guidance to the design and alignment of an asymmetrical crossed Czerny-Turner spectrometer.