Non-invasive Amide Proton Transfer Imaging and ZOOM Diffusion-Weighted Imaging in Differentiating Benign and Malignant Thyroid Micronodules

Background: Pre-operative non-invasive differentiation of benign and malignant thyroid nodules is difficult for doctors. This study aims to determine whether amide proton transfer (APT) imaging and zonally oblique multi-slice (ZOOM) diffusion-weighted imaging (DWI) can provide increased accuracy in differentiating benign and malignant thyroid nodules.Methods: This retrospective study was approved by the institutional review board and included 60 thyroid nodules in 50 patients. All of the nodules were classified as malignant (n = 21) or benign (n = 39) based on pathology. It was meaningful to analyze the APT and apparent diffusion coefficient (ADC) values of the two groups by independent t-test to identify the benign and malignant thyroid nodules. The relationship between APT and ZOOM DWI was explored through Pearson correlation analysis. The diagnostic efficacy of APT and ZOOM DWI in determining if thyroid nodules were benign or malignant was compared using receiver operating characteristic (ROC) curve analysis.Results: The mean APTw value of the benign nodules was 2.99 ± 0.79, while that of the malignant nodules was 2.14 ± 0.73. Additionally, there was a significant difference in the APTw values of the two groups (P < 0.05). The mean ADC value of the benign nodules was 1.84 ± 0.41, and was significantly different from that of the malignant nodules, which was 1.21 ± 0.19 (P < 0.05). Scatter point and Pearson test showed a moderate positive correlation between the APT and ADC values (P < 0.05). The ROC curve showed that the area under the curve (AUC) value of ZOOM DWI (AUC = 0.937) was greater than that of APT (AUC = 0.783) (P = 0.028).Conclusion: APT and ZOOM DWI imaging improved the accuracy of distinguishing between benign and malignant thyroid nodules. ZOOM DWI is superior to APTw imaging (Z = 2.198, P < 0.05)

Workability study of sand-bentonite-cement mixtures for construction of two-phase cut-off wall

The workability of fresh materials is critical for sand-bentonite-cement cut-off wall; however, previous studies are limited to the one-phase construction method, not the two-phase. Hence, this study attempts to fill the gap. First, series of flowability and bleeding tests on sand-bentonite mixtures were conducted (1st phase); subsequently, cement slurry was added to mixtures (2nd phase) to investigate its effect on the workability. The results indicated that, for sand-bentonite mixtures with required workability for 1st phase of construction, the addition of cement caused significant increase in flowability and bleeding, i.e. reducing the workability for 2nd phase, especially for sodium bentonite. The reason was revealed as the short-term interactions (mainly cation exchange) between bentonite and cement hydration products, reducing water retention capacity and swelling potential of bentonite.Ministry of Education (MOE)This research is supported by the Ministry of Education, Singapore, under its Academic Research Fund Tier 2 (MOE-T2EP50220-0004)

Computation and Verification of Spatial Rate Equations for an Electro-Optically Q-Switched Laser-Diode Side-Pumped Nd:YAG Laser

In a side-pumped laser module, we simulate the pumping power distribution across the cross-section of Nd:YAG rods at varying diameters. The coupled rate equations with the spatial overlap efficiency for a four-level actively Q-switched side-pumped laser are considered complete. After a Q-switched pulse terminates, the expressions of laser output parameters are derived. We assess the single pulse energy, pulse width, and peak power using the analysis function. The 200 Hz Q-switched side-pumped Nd:YAG laser with a peak power of 103 kW and beam quality factors M2 = 1.67 is developed to the validity of theoretical models

Comparison of MgO-GGBS, CaO-GGBS, and cement for construction of two-phase TRD cut-off walls in sand: workability, strength, and permeability

Cement–bentonite–soil cut-off walls installed using the trench remixing and deep (TRD) wall method have been widely used to control seepage. The TRD construction is usually executed in two-phase cut-off walls; however, previous studies mainly focus on the properties of the one-phase cut-off walls. Besides, chemical interactions between bentonite and cement will induce a reduction in the swelling potential and water retention capacity of bentonite, leading to a weakness in its seepage barrier performance. Thus, it is of great significance to develop alternative cementitious materials to replace cement for the construction of cement–bentonite–soil cut-off walls. Ground granulated blastfurnace slag (GGBS) has been increasingly used for partial or full replacement of cement in geotechnical engineering. In this study, the performance of cut-off walls constructed using the two-phase TRD method was fully evaluated based on the use of GGBS with the activators of magnesia (MgO) and quicklime (CaO) to replace cement. A series of laboratory tests were first conducted to evaluate the workability (i.e., flowability and bleeding) of fresh bentonite–sand mixtures with four types of binder slurry (i.e., cement, GGBS, MgO-GGBS, and CaO-GGBS). Subsequently, binder–bentonite–sand mixtures that achieved the required workability were selected for unconfined compressive strength (UCS) and permeability tests. The results indicated that both the flowability and the bleeding water of fresh mixtures were remarkably increased by the addition of cement or CaO-GGBS compared to that of GGBS or MgO-GGBS, easily exceeding the acceptable range. It may be attributed to the cation exchange of Ca2+ released from cement or CaO hydration with Na+ in bentonite; however, this interaction might be concealed for the one-phase cut-off walls. More importantly, MgO-GGBS showed much better performance in the strength and permeability than cement; for example, the average 28-day UCS could reach up to 1.12 MPa for the binder type of MgO/GGBS = 1:9 at the binder content of 10% and bentonite content of 3%, four times that of cement. On the other hand, it is revealed that the addition of a large amount of bentonite does not always make a significant improvement on the permeability of two-phase cut-off walls. Overall, the results promote the application of MgO-GGBS as a potential substitute for cement in cut-off walls using the two-phase TRD method.Ministry of Education (MOE)Submitted/Accepted versionThis study is financially supported by the Ministry of Education, Singapore, under its Academic Research Fund Tier 2 (MOE-T2EP50220-0004) and the National Natural Science Foundation of China (51938005 and 52090082). The first author acknowledges the International Post doctoral Fellowship Program from the Office of China Postdoc Council (20190043)

Defect identification of bare printed circuit boards based on Bayesian fusion of multi-scale features

The aim of this article is to propose a defect identification method for bare printed circuit boards (PCB) based on multi-feature fusion. This article establishes a description method for various features of grayscale, texture, and deep semantics of bare PCB images. First, the multi-scale directional projection feature, the multi-scale grey scale co-occurrence matrix feature, and the multi-scale gradient directional information entropy feature of PCB were extracted to build the shallow features of defect images. Then, based on migration learning, the feature extraction network of the pre-trained Visual Geometry Group16 (VGG-16) convolutional neural network model was used to extract the deep semantic feature of the bare PCB images. A multi-feature fusion method based on principal component analysis and Bayesian theory was established. The shallow image feature was then fused with the deep semantic feature, which improved the ability of feature vectors to characterize defects. Finally, the feature vectors were input as feature sequences to support vector machines for training, which completed the classification and recognition of bare PCB defects. Experimental results show that the algorithm integrating deep features and multi-scale shallow features had a high recognition rate for bare PCB defects, with an accuracy rate of over 99%

Exploring barriers to influenza vaccine uptake and recommendation among healthcare providers in the community in China: A qualitative study

Healthcare providers (HCPs) are recommended for priority influenza vaccination due to their high risk of contracting influenza. HCPs greatly aid in targeted population immunization campaigns. Therefore, understanding the factors that influence HCPs’ decisions to get vaccinated and to recommend influenza vaccination is essential. However, there currently needs to be more evidence on this topic in China. Qualitative interviews using a semi-structured interview method were conducted with 180 HCPs from urban community hospitals and town hospitals in four cities in Shandong Province during August 2023. The interview content was analyzed using thematic analysis to identify the variables impacting the vaccination and recommendation practices of HCPs, as well as their suggestions for improving vaccination services. The results will help support the future development of precise intervention measures as well as focused education and training