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Objective: We aimed to quantify the extent of salivary gland fibrosis using shear‐wave elastography (SWE) to assess its diagnostic value for primary Sjögren syndrome (pSS). Methods: A total of 58 pSS patients and 44 controls underwent SWE ultrasound evaluation of the parotid and submandibular glands. We measured the degree of salivary gland fibrosis in all participants and investigated the diagnostic accuracy of SWE for pSS and its relationship to disease progression. Results: The diagnostic sensitivity, specificity, and accuracy of pSS were highest when the critical Young's modulus values of the parotid and submandibular glands were 18.4 and 15.9 kPa, respectively, effectively improving the diagnostic value of pSS. The area under the SWE curve of the submandibular gland was higher than that of the parotid gland (z = 2.292, P = 0.02), suggesting that the submandibular gland was damaged earlier. The mean parotid gland thickness of pSS patients was thicker than in healthy controls (mean ± standard deviation 2.5 ± 0.3 vs 2.4 ± 0.2, P = 0.013]. SWE had a 70.3% sensitivity for diagnosing pSS patients with a disease duration of 5 years, but this did not differ significantly from pSS patients with a longer disease duration. Conclusions: SWE is a valid diagnostic method for pSS. The degree of salivary gland fibrosis related to secretory function and pathological progression, and quantitative measurements of tissue elasticity provide objective criteria for predicting damage in pSS. [ABSTRACT FROM AUTHOR]

Icequakes associated with crevassing provide key information on stress fields and water flow pathways inside glaciers, conditions which are sensitive to temperature and precipitation. In this study, we analyse seismic data from 321 days recorded by five broad-band seismometers on Urumqi Glacier No. 1, Tianshan, China, to investigate the source characteristics of icequakes. We first apply a multidimensional autoregressive maximum-likelihood algorithm to detect 12 template events from 62 days of continuous waveform data. The centroid locations of the 12 template events are located using a grid-search approach. We then obtain a catalogue of 41   895 icequakes by compiling all seismic data through a template-matching method. The local magnitudes of all icequakes range between −3.3 and 0.5, with a completeness magnitude of −2.95 and Gutenberg–Richter b -value of 1.08. The particle motion and frequency contents of the 12 template events show that the dominant phases on the vertical component are Rayleigh waves at 5–40 Hz, suggesting that these icequakes were generated by near-surface crevasses. The average daily icequake number for each month and diurnal icequake variations show clear seasonal features. The icequakes may be related to growth of the surface crevasses due to additional melting water and precipitation in summer and to the thermal contraction of the ice body in winter. [ABSTRACT FROM AUTHOR]

Automatic segmentation of polyps during colonoscopy can help doctors accurately find the polyp area and remove abnormal tissues in time to reduce the possibility of polyps transforming into cancer. However, the current polyp segmentation research still has the following problems: blurry polyp boundaries, multi-scale adaptability of polyps, and close resemblances between polyps and nearby normal tissues. To tackle these issues, this paper proposes a dual boundary-guided attention exploration network (DBE-Net) for polyp segmentation. Firstly, we propose a dual boundary-guided attention exploration module to solve the boundary-blurring problem. This module uses a coarse-to-fine strategy to progressively approximate the real polyp boundary. Secondly, a multi-scale context aggregation enhancement module is introduced to accommodate the multi-scale variation of polyps. Finally, we propose a low-level detail enhancement module, which can extract more low-level details and promote the performance of the overall network. Extensive experiments on five polyp segmentation benchmark datasets show that our method achieves superior performance and stronger generalization ability than state-of-the-art methods. Especially for CVC-ColonDB and ETIS, two challenging datasets among the five datasets, our method achieves excellent results of 82.4% and 80.6% in terms of mDice (mean dice similarity coefficient) and improves by 5.1% and 5.9% compared to the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

This paper reports that N -arylenamines can be converted into quinoxalines via tandem azidation/intramolecular C H amination under visible light irradiation by using 1-azidyl-1,2-benziodoxole as the azidating agent. The substituent was found to have a critical influence on the reaction, and thus different conditions were required to fit the substrates of varied structural features. The conversion of N -aryl-3-arylenamine esters into the corresponding quinoxalines proceeded well under metal-free conditions, whereas Cu(OAc) 2 was required when N -aryl-3-trifluoromethyl enamine esters were used as the substrates. This method was also applied to the preparation of 2,3-diarylquinoxalines by using Ru(bpy) 3 Cl 2 as the photoredox catalyst. The reactions revealed herein provide an efficient approach towards quinoxalines. [ABSTRACT FROM AUTHOR]

N-Alkyl enamines can be transformed into 2,4,5-trisubsituted imidazoles by reacting with (diacetoxy-iodo)-benzene and TMSN3 under the catalysis of a copper salt such as Cu-(OAc)2. Tetrabutyl ammonium iodide was also capable of promoting the reaction. The transformation from N-alkyl enamines into 2,4,5-trisubsituted imidazoles took place in a domino azidation/intramolecular C-(sp3)–H amination pattern. The present reaction provides a new efficient method for the preparation of 4-(trifluoromethyl) imidazoles. [ABSTRACT FROM AUTHOR]

This paper reports a new method for the synthesis of 3-aminooxindole derivatives. Ethyl 2-( N -arylcarbamoyl)-2-iminoacetates, which can be prepared from the reaction of α-ethoxycarbonyl-α-bromo- N -phenylacetamides with sodium azide, were found to undergo Friedel–Crafts cyclization to afford 3-aminooxindoles in high yield by the catalysis of an acid such as BF 3 ⋅OEt 2 . α-Aryl-α-azido- N -arylamides, on the other hand, were transformed to 3-arylaminooxindoles via a tandem 1,2-aryl migration-dinitrogenation and cyclization by the action of triflic acid. As both ethyl 2-( N -arylcarbamoyl)-2-iminoacetates and α-aryl-α-azido- N -arylamides are easily accessible, the current reactions are expected to be practically useful in the synthesis of 3-aminooxindole derivatives. [ABSTRACT FROM AUTHOR]

This paper reveals that visible light irradiation with Ru(phen)3Cl2 as photocatalyst can induce ethyl 2-(N-arylcarbamoyl)-2-chloroiminoacetates to undergo N-Cl cleavage to give a-(aminocarbonyl) iminyl radicals under an argon atmosphere. The subsequent cyclization of the thus formed iminyl radicals affords quinoxalin-2(1H)- one products in good yield in the presence of an inorganic base such as Na2CO3. The reactions proceeded very well even without using a photocatalyst when DMF was used as the solvent. These protocols provide a new, simple method for the generation of iminyl radicals, and the reactions described herein constitute an efficient method for the synthesis of quinoxalin-2(1H)-one derivatives. [ABSTRACT FROM AUTHOR]

28 examples [ABSTRACT FROM AUTHOR]

α-Imino-N-arylamides [e.g. (I)] undergoes Friedel-Crafts cyclization to give 3-aminooxindoles [e.g. (II)] in high yields and the products can also be obtained from α-bromo-N-arylamides [e.g. (X)] in a one-pot fashion. [ABSTRACT FROM AUTHOR]

The reaction is mentioned to fail for chloroiminoacetates bearing an ortho-substituent. [ABSTRACT FROM AUTHOR]

Melanoma is a main factor that leads to skin cancer, and early diagnosis and treatment can significantly reduce the mortality of patients. Skin lesion boundary segmentation is a key to accurately localizing a lesion in dermoscopic images. However, the irregular shape and size of the lesions and the blurred boundary of the lesions pose significant challenges for researchers. In recent years, pixel-level semantic segmentation strategies based on convolutional neural networks have been widely used, but many methods still suffer from the inaccurate segmentation of fuzzy boundaries. In this paper, we proposed a multi-scale hybrid attentional convolutional neural network (MHAU-Net) for the precise localization and segmentation of skin lesions. MHAU-Net has four main components: multi-scale resolution input, hybrid residual attention (HRA), dilated convolution, and atrous spatial pyramid pooling. Multi-scale resolution inputs provide richer visual information, and HRA solves the problem of blurred boundaries and enhances the segmentation results. The Dice, mIoU, average specificity, and sensitivity on the ISIC2018 task 1 validation set were 93.69%, 90.02%, 92.7% and 93.9%, respectively. The segmentation metrics are significantly better than the latest DCSAU-Net, UNeXt, and U-Net, and excellent segmentation results are achieved on different datasets. We performed model robustness validations on the Kvasir-SEG dataset with an overall sensitivity and average specificity of 95.91% and 96.28%, respectively. [ABSTRACT FROM AUTHOR]

The reduction of the total amount of coal, a priority energy to achieve the goal of carbon peak and carbon neutralization, has become the focus of domestic and foreign scholars. Taking coal consumption in Shandong Province as the research object, this paper builds a methodology system that uses aggregate reduction indicators to force coal consumption control path research based on the method of scenario combination + system dynamics (SD) predictive analysis. The results show that the key factors restricting coal consumption based on path analysis and SD sensitivity analysis are overlapped. Based on this, 21 scenarios based on different combinations of the aforementioned key elements are constructed. According to SD scenario simulation and TOPSIS quantitative analysis, the GM-IM-EH-PM scenario development mode easily accomplishes the reduction task and is the optimal scenario development mode suitable for the future development of Shandong Province. Meanwhile, during the 14th Five-Year Plan period, the appropriate development ranges of gross domestic product (GDP) growth rate, the proportion of the secondary industry, energy consumption intensity of secondary industry, and the proportion of industrial pollution control investment in GDP in Shandong Province are recommended to be 5.5%–5.6%, 31%–32%, 0.58–0.60, 1.54–1.56, respectively. The research conclusions can provide a useful reference for the government to formulate coal reduction plans. [Display omitted] • Methodology system of coal regulation path is constructed. • Key situational factors affecting coal consumption are obtained. • A variety of situational combination patterns is developed. • Conclusions provide recommendations for coal reduction programs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Shenzhen's urban ecological security assessment through the PSR model. • Identification of key influencing factors of urban ecological security through factor analysis. • Prediction of future urban ecological security through Monte Carlo. • Scientific theoretical guidance for urban ecological sustainable development. The rapid development of urbanization has triggered the contradiction between population, resources and environment. As a result, urban ecological security has attracted more and more attention, and has gradually become the key to restricting the sustainable development of urban social economy. This work constructs a dynamic urban ecological security assessment and prediction research framework, which is verified by taking Shenzhen, a typical big city in China, as an example. Specifically, urban ecological security is evaluated through the "pressure-state-response" (PSR) model, and its key influencing factors are identified by the coupling factor analysis method. Finally, the future ecological security of the city is predicted and analyzed by Monte Carlo. The results show that the comprehensive safety index of Shenzhen urban ecosystem is increasing, and its key impact indicators are comprehensive development factors and human settlements factors respectively. Additionally, it is anticipated that Shenzhen's urban ecological security level will reach a comfortable level in 2025. To sum up, according to the results of urban ecological assessment and prediction, targeted suggestions on the improvement path of ecological security are put forward. It is suggested that Shenzhen should continue to increase investment in environmental protection, science and technology and other fields to ensure the sustainable development of the urban ecosystem. Using the city of Shenzhen as a case study, this research examines the typical regulatory path for urban ecological security. On the one hand, it can provide a methodological framework for the historical evaluation and future prediction of urban ecological security in China and possibly the entire world. And on the other hand, it can provide a theoretical reference for cities to formulate policies for ecological sustainable development. [ABSTRACT FROM AUTHOR]

Cities are the main source and gathering place of carbon emissions. Therefore, it is an effective way to reach peak CO 2 emissions before 2030 to make carbon emission prediction and implement differentiated carbon emission reduction schemes according to local conditions at the urban level. Taking Shandong Province as an example, this paper comprehensively explored the impact of 16 socio-economic factors on carbon emissions of different cities through the extended STIRPAT model. In order to reduce the uncertainty of the research results and achieve "one city, one policy", firstly, the influencing factors of carbon emissions in different cities were screened through ridge regression equation, which were used as specific parameters of different cities in the scenario setting. Secondly, based on the actual development of different cities, this paper obtained the scenario combination scheme by freely combining different influencing factors to predict the peak time and peak value of carbon emissions. Based on the above measures, it could not only reflect the heterogeneous development of cities, but also ensure that the research results are close to the actual development of cities. The results show that 16 cities in Shandong Province show differential peak attainment. Among them, 8 cities have the best peak year around 2025, 5 cities have the best peak year around 2028, and 2 cities can achieve the peak before 2030. A comprehensive analysis of the timing and peaking of carbon emissions suggests that the best overall peaking year for Shandong Province could be 2028. In addition, according to the different influencing factors of carbon emission peak in each city, a set of carbon emission reduction scenarios with urban differentiation reaching the peak is proposed. This could provide a more comprehensive path choice direction for local governments to formulate carbon emission reduction action plans. Furthermore, this paper could be used as a reference for other provinces in China or other national regions to explore urban differentiated carbon peaking and to formulate operable carbon peaking solutions. [Display omitted] [ABSTRACT FROM AUTHOR]