A direct Csp3-H bond oxidative thioesterification of methyl ketones with aromatic thiols/disulfides promoted by TBAI/K2S2O8 has been developed. The reaction provides successfully a simple and efficient method for the synthesis of functionalized α-ketothioesters of aromatic thiols. This practical methodology exhibits readily available starting materials, large-scale applicability, synthetic application, and broad functional group tolerance. A possible mechanism for the transformation is proposed.
A simple and efficient approach for the synthesis of 4-spiro-1,4-DHP derivatives has been developed, involving one-pot three-component reaction of isatins, N,N-dimethylenaminones with ammonium acetate in EtOH–water solution promoted by acetic acid. Compared with the previous [1+2+3]-cyclisation method, this [1+2+1+2]-cyclisation procedure has advantages as it is more environmentally friendly, has easier operational simplicity, and requires milder reaction conditions. Moreover, these novel compounds have been obtained in moderate to good yields and their structures have been confirmed by 1 H NMR, 13 C NMR and IR and HRMS spectroscopy.
The microstructure of tungsten, a primary candidate for the first wall of Tokamak devices, affects the retention and permeation of hydrogen isotopes. These have a close connection to the tritium inventory. In this work, the tungsten microstructure was tuned by annealing and intense 15,700 displacements per atom (dpa) keV-W-self-ion implantation. The samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The results reveal that the annealing treatment has little influence on the crystallite size but decreases the number of defects such as vacancies, which relates to the bulk microstructure. Moreover, ion implantation changes the sample surface from a smooth quasi-mirror to a grey morphology with various voids. The deuterium retention is suppressed by the decrease of bulk defects due to annealing, but does not present a saturation with the displacement damage increase. It is interesting to note that in permeation, the rate limiting step is bulk diffusion while the deuterium permeability is enhanced for samples with a surface modification. The possible permeation mechanisms and their relation with the sample microstructure are discussed in this work.
Abstract In this study, wave propagation characteristics in functionally graded (FG) piezoelectric sandwich nanoplates under electro-thermal loading are investigated. The sandwich nanoplates comprise piezoelectric layers, with a FG layer in the middle. The nanoplates are deposited on a viscoelastic substrate, and the effective material parameters of the FG interlayers are determined using the Mori-Tanaka homogenization model. To specifically examine the influence of surface (SE) and scale effects, governing equations are derived from the unified shear deformation theory and Hamilton's principle, incorporating the theoretical frameworks of surface piezoelectricity theory and nonlocal strain gradient theory. Thereafter, the characteristic equations are analytically solved to obtain numerical effects of wave dispersion relations. The effects of various parameters, such as surface parameters, scale parameters, viscoelastic parameters, and external loads on the wave propagation characteristics are investigated in detail. The piezoelectric SE is related to the scale parameters. Surface density decreased the frequency, and the degree of influence of both surface piezoelectric parameters and residual stress on the frequency decreased rapidly with the increase in the thickness of the piezoelectric layer.
Non-alcoholic fatty liver disease (NAFLD) is closely correlated to visceral obesity, dyslipidaemia, insulin resistance and type 2 diabetes mellitus. We sought to assess the association between a specific stroke subgroup, brainstem infarctions (BSIs) and NAFLD. Furthermore, we evaluated whether NAFLD is an independent risk factor in patients with BSIs.Non-alcoholic fatty liver disease was assessed in 306 patients with radiologically confirmed BSIs via liver ultrasound. Differences between patients with and without NAFLD were compared. Data associated with stroke severity and progression after admission were collected.Non-alcoholic fatty liver disease was found in 130 (42.5%) patients with acute BSIs; 58 (19.0%) had National Institutes of Health Stroke Scale scores >7 and 57 (18.6%) had progression after admission. Initial National Institutes of Health Stroke Scale scores, incidence of progression and stroke severity, and modified Rankin Scale scores at discharge were significantly higher in patients with NAFLD than in those without NAFLD. NAFLD was associated with stroke severity [Cox regression: hazard ratio (HR), 2.243; 95% confidence interval (CI), 1.254-4.013, P < 0.01]. This risk remained statistically significant after controlling for age, gender, diabetes mellitus and C-reactive protein (HR, 2.327; 95% CI, 1.252-4.324, P < 0.01). In addition, NAFLD was associated with progression (HR, 2.155; 95% CI, 1.201-3.865, P < 0.05) and remained significant after controlling for age, gender, diabetes mellitus, fibrinogen and C-reactive protein (HR, 2.378; 95% CI, 1.260-4.486, P < 0.01).These results suggest that NAFLD is a potential risk factor when evaluating the severity and progression of acute BSIs. This relationship is independent of classic risk factors and metabolic syndrome features.
Sustainable development has become a global consensus, and green innovation is the key starting point, and it has become a ballast stone and stabilizer for regional ecological environmental protection and high-quality economic development. Based on GIS tools and multi-method models, this paper studies the spatio-temporal characteristics and influence mechanism of green innovation in three major urban agglomerations in China from 2010 to 2019 from the perspective of economic geography. The study found that: (1) the green innovation efficiency of the three major urban agglomerations in China is in a fluctuating upward trend as a whole, with obvious spatial disequilibrium; (2) from the spatial point of view, the characteristics of global spatial agglomeration distribution have positive spatial correlation, and the law of local spatial autocorrelation is obvious, and the spatio-temporal pattern transitions from “low efficiency, big difference” to “high efficiency, small difference” during the study period; (3) there are obvious spatial spillover and diffusion effects on the green innovation efficiency of the three major urban agglomerations in China as a whole. However, the spatial dependence of green innovation efficiency is inconsistent in China’s three major urban agglomerations; the YRD Urban region and the PRD Urban region show a positive impact, while the JJJ Urban region shows a negative impact; (4) the level of economic development, the operating environment of science and technology, and the guiding factors of government system function with significant differences and regional spatial heterogeneity on the efficiency of green innovation in the three major urban agglomerations in China.
Abstract On the basis of discussing the relationship between urban ecosystem and sustainable development, the evaluation index system of sustainable development of human settlements environment in Tianjin was constructed from four aspects: social development level, economic development level, natural development level and sustainability level. The evaluation index of Tianjin ecosystem and its sustainable development level in recent 10 years were calculated by simple arithmetic average method. The relationship between sustainable development of ecosystem and economic development in Tianjin was quantitatively evaluated. The results show that the ecosystem of Tianjin is developing in a sustainable direction, basically in line with the stage of economic development, but there are still some shortcomings which need to be improved urgently.
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