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A compact evanescent wave detection platform (EWDP) is developed for the detection of fluorescence gold nanoclusters. The EWDP employs a simple optical system and a Si-based photodetector SOP-1000 assembly to improve the optical efficiency and detection sensitivity. A microfluidic sample cell is also used to decrease the amount of analyte to 200 μL (The volume of sample cell is really about 30 μL). On this basis, we design a strategy for detecting dopamine (DA) based on the photoinduced electron transfer (PET) quenching mechanism. By introduction of tyrosinase (TYR) during the detection, the testing time is shortened to 1 min. The fluorescence emission signal decreased dramatically and the quenching ratio (F0–F)/F0 is linearly related to the concentration of DA in the range of 0.03–60 μM with a detection limit of 0.03 μM. Additionally, this detection platform has potential applications for DA fast detection in the microsamples.

Protecting the environment is now a major aspect of corporate social responsibility. However, voluntary carbon disclosure includes private information on future sustainability that external stakeholders cannot easily verify. Drawing on information asymmetry theory, we predict that companies with higher carbon information asymmetry between insiders and outsiders have a greater incentive to voluntarily engage an external party for the independent assurance of their greenhouse gas statements. Using data from the CDP, we test this hypothesis and find that our proxies for carbon information asymmetry (e.g., greenhouse gas emissions, energy structure) are significantly associated with the adoption of carbon assurance. Further analyses suggest that the probability of carbon assurance is enhanced when carbon disclosure is inadequate to diminish information asymmetry. Finally, our sample companies adopted carbon assurance in addition to financial auditing. This highlights the key point that resolving carbon information asymmetry requires carbon assurance, which cannot be substituted for by financial auditing.

The approach of simulation plays an essential role in the research of PET/CT imaging technology. In this paper, a digital phantom simulation study of the GE ST PET/CT acquisition implemented by GATE (Geant4 Application Tomography Emission) software packages and NCAT(dynamic NURBS-based cardiac-torso phantom)was presented. GATE provides abundant of functions to simulate both SPECT/PET imaging procedure and phantom generation. The simulation experiment based on three different kinds of digital phantoms were designed and implemented. The simulation output of GATE was converted to the data format that the STIR (Software for Tomographic Image Reconstruction) requires to reconstruct image by the OSEM (ordered subsets expectation-maximization) algorithm and the result of image reconstruction could be present in a 3-D space. The initial simulation result base on digital phantoms shows that GATE and STIR can be used to simulate PET/CT imaging.

This paper proposes an image segmentation method based on the combination of the wavelet multi-scale edge detection and the entropy iterative threshold selection. Image for segmentation is divided in to two parts by high and low frequency. In the high-frequency part the wavelet multi-scale is used for the edge detection, and the low-frequency part conducts on segmentation using the entropy iterative threshold selection method. Through the consideration of the image edge and region, a CT image of the thorax is chosen to test the proposed method for the segmentation of the lungs. Experimental results show that the method is efficient to segment the interesting region of an image compared with conventional methods.

The system matrix calculation plays an important role in the improvement of the speed and the quality of image reconstruction in PET (Positron Emission Tomography) imaging. It involves the calculation of a certain sequence of projection coefficient, which is generated through classifying different situations of the intercepted photon rays with the grid. In this study, a fast and simple algorithm for computing the projection coefficient is proposed. Compared with those tradition- al methods, the grid index of the proposed approach is determined by rows an d columns in the two-dimensional coordinate , respectively. Experimental results based on GAT E (Geant4 Application for Tomographic Emission) simulating PET imaging show that the proposed algorithm is efficient to build up a system matrix.

Image reconstruction plays an important role in medical imaging technology, the quality of reconstructed image will directly affect the results of clinical diagnosis. How to assess the quality of the image is an attractive research topic. In this paper, a comparative study of quality assessment for medical image with seven common algorithms was presented, the images were reconstructed from the result of the GATE (Geant4 Application for Tomographic Emission) simulation of PET/CT imaging, then the algorithms are used to assess the reconstructed image. The results of comparative experiment show that the algorithms have their individual characteristics to assess image quality, appropriate method or a comprehensive method should be selected for the assessment of reconstructed medical image depending on clinical practice.

The approach of simulation plays an essential role in the research of PET/CT imaging technology. In this paper, a simulation study of the GE ST PET/CT acquisition implemented by GATE (Geant4 Application Tomography Emission) software packages was presented. GATE provides abundant of functions to simulate both SPECT/PET imaging procedure and phantom generation. The simulation experiment based on the geometry phantom was designed and implemented. The simulation output of GATE was converted to the data format that the STIR (Software for Tomographic Image Reconstruction) requires to reconstruct image by the OSEM (ordered subsets expectation-maximization) algorithm and the result of image reconstruction could be present in a 3-D space. The initial simulation result shows that GATE and STIR can be used to simulate PET/CT imaging.