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We report single-step electrocatalytic N-acylation and S-cyclization synthesis of thiazolimide with excellent tolerance of sensitive functional groups which prevents thermal reactions.

Rh-catalyzed highly chemo- and enantioselective hydrogenation of chromone-2-carboxylic acids was successfully established for the first time, providing a wide range of enantiopure chromanone-2-carboxylic acids with excellent results (up to 97% yield and 99% ee) and high efficiency (up to 10 000 TON). The carboxylic group in the substrate was demonstrated to play a vital role and an enantio-induction mode was elucidated by DFT calculation. This hydrogenation protocol provided straightforward access to various bioactive chromanoids.

The widespread applications of aggregation-induced emission luminogens (AIEgens) inspire the creation of AIEgens with novel structures and functionalities. In this work, we focused on the direct and efficient synthesis of a new type of AIEgens, imidazo[1,5-a]pyridicne derivatives, via iodine mediated cascade oxidative Csp2–H or Csp–H amination route from phenylacetylene or styrenes under mild conditions. The resulted compounds showed excellent AIE characteristics with tunable maximum emissions, attractive bioimaging performance, and potential anti-inflammatory activity, which exert broad application prospects in material, biology, medicine, and other relevant areas.

The Guangdong–Hong Kong–Macao Greater Bay Area urban agglomeration is an urban agglomeration with some of the most intensive urbanization since 1980s. A large amount of cultivated land, forest land, water bodies and other land types in the region has been occupied by construction land, resulting in fragmented ecological landscapes and biodiversity in the region and causing many other ecological problems. Based on this, this paper takes the Guangdong–Hong Kong–Macao Greater Bay Area as a case study, constructs an ecological network of the dispersion scale of five species from 1990 to 2020 based on a morphological spatial pattern analysis (MSPA) method, identifies the ecological groups in the network and uses the core node-based community evolution path tracking algorithm to analyze the ecological groups in order to explore the changes of ecological network connectivity at different scales in the region and to reveal the overall and local characteristics and changes of the migratory space of terrestrial mammals with different dispersion capabilities. The research results show that: (1) From 1990 to 2020, the area of construction land in the Guangdong–Hong Kong–Macao Greater Bay Area increased sharply, with good connectivity in the northwest, southwest and eastern regions and poor connectivity in the central region. (2) There are obvious differences between the overall and local changes in the connectivity trends of multi-scale regional ecological networks. On the whole, the overall ecological connectivity of the ecological network at each scale showed a gradual upward trend, and the overall connectivity index IIC and the possible connectivity index PC gradually increased with the increase of the maximum dispersal distance of species. From the perspective of local patches, the larger the species dispersion scale, the larger the value of the revised betweenness centrality index and the patch possible connectivity index. (3) The distribution of ecological groups at different species dispersion scales is different, and the smaller the dispersal scale of the species, the greater the distribution of ecological groups. Small-scale species are limited by the maximum dispersal distance, and the range of their ecological groups is generally small. Small-scale (3 km), mesoscale (10 km) and large-scale (30 km) core nodes of ecological groups show a gradual increase trend, and the overall connectivity of ecological groups has improved. However, the core nodes of the extra-large-scale (60 km) and ultra-large-scale (100 km) ecological groups show a trend of decreasing fluctuations, and the overall connectivity within the ecological group has declined. This study is helpful to clarify the structural characteristics of regional ecological space and provide a theoretical basis for regional ecological planning.

Herein, we report an efficient electrochemical activation of the C-C bond of aryl ketones for the preparation of amides under catalyst- and external-oxidant-free conditions using aliphatic amines as the N source. Under environmentally benign electrolysis conditions, a series of amides were synthesized in good yield. Our control experiments revealed that electricity plays an important role in this transformation.

This paper illustrates a method to automate the 3D designing process of Simple harmonic motion (SHM) cam profile in CATIA CAD package. In a more user-friendly approach, a graphical user interface (GUI) is developed, where the users can enter the cam parameters and obtain 3D CAD model as direct result. It is observed that 90% time will be reduced by using this automated designing and also chance of errors also reduces. Due to the high follower load impacting on cam profile, high contact stresses induced on the component surfaces due to the asperity contacts cause the cam or roller surfaces to be subjected to high risk of contact fatigue failure. Present work focuses on comparing fatigue life of SHM and Cycloidal cam functions. The fatigue life is assessed using finite element analysis (FEA) in ANSYS Workbench. We have considered follower as flat-faced and frictionless contact between cam and follower in this study. After developing the 3D model of SHM and cycloidal cam profile through automated method, both the models were then imported to ANSYS for fatigue analysis under the same loading conditions. It has been found that cycloidal function has more fatigue life than SHM function.

Exploring the spatial and temporal distribution characteristics of air quality has become an important topic for the harmonious development of human and nature. Based on the hourly data of CO, O3, NO2, SO2, PM2.5 and PM10 of 1427 air quality monitoring stations in China in 2016, this paper calculated the annual mean and annual standard deviation of six air quality indicators at each station to obtain 12 variables. Self-Organizing Maps (SOM) and K-means clustering algorithms were carried out based on MATLAB and SPSS Statistics, respectively. Kriging interpolation was used to get the clustering distribution of air quality and fluctuation in China, and Principal Component Analysis (PCA) was used to analyze the main factors affecting the clustering results. The results show that: (1) Most areas in China are low-value regions, while the high-value region is the smallest and more concentrated. Air quality in northern China is worse, and the annual fluctuations of the indicators are more dramatic. (2) Compared with AQI, AQFI has a strong indication significance for the comprehensive situation of air quality and its fluctuation. (3) The spatial distribution of SOM clustering results is more discriminative, while K-means clustering results have a large proportion of low-mean regions. (4) PM2.5, PM10 and CO are the main pollutants affecting air quality and fluctuation, followed by SO2, NO2 and O3.

Excessive vibration of aircraft wings during flight is harmful and may cause propagation of existing cracks in the material, leading to catastrophic failures as a result of material fatigue. This study investigates the variations of modal characteristics of aircraft wings with respect to changes in the structural configurations. We develop parametric Computer-Aided Design (CAD) models to capture new design intend on the aircraft wing architectures. Subsequent Finite Element Analysis (FEA) based vibration analysis is performed to study the effects of architecture changes on the wing’s natural frequencies and mode shapes. It is concluded that the spar placement and the number of ribs have significant influence on the wing’s natural vibration properties. Integrating CAD modelling and FEA vibration analysis enables designers to develop alternative wing architectures to implement design requirements in the preliminary design stage.

A highly efficient intramolecular asymmetric reductive amination transformation catalyzed by an iridium complex of tBu-ax-Josiphos has been realized via a one-pot N-Boc deprotection/cyclization/asymmetric hydrogenation sequence. This convenient and practical method provides chiral tetrahydroisoquinolines, which are of great importance and common in natural products and biologically active molecules, in moderate to high yields (78–96%) and good to excellent enantioselectivities (80–99% ee).

Heart failure is the terminal stage of many cardiovascular diseases and is considered to be closely related to oxidative stress. Early understanding of pathogenesis can greatly improve the treatment and reduce the mortality of heart disease. In this work, based on the analysis of coumarin derivates by theoretical calculations, we designed and synthesized a fluorescent probe BCO with a large Stokes shift (107 nm) and excellent selectivity toward H2O2 in a living system. The distribution of H2O2 in the heart and thoracic aorta tissues was imaged with the aid of the probe BCO, which demonstrated that the cellular H2O2 level is upregulated in heart failure. This work provides a useful tool, BCO, for the evaluation of cellular oxidative stress and to further understand the pathophysiology process of heart disease.

Much research has focused on residual stress detection, analysis and elimination for alloy materials. There is however limited work considering residual stress in gray cast iron materials (HT200, 2...

Blisk of aerospace engine is one of the sophisticated key parts in the aviation, which is difficult to machine considering its structural and material properties. The present paper develops a five-axis CNC milling machine for fabricating blisk with high-efficiency and high-quality as well as ensuring this milling machine with high precision and precision retention. Therefore, a precision analysis method is proposed to implement precision evaluation and precision life prediction of this milling machine. The five-axis CNC milling machine is used to machine blisk and measured about the error condition of various key components at different downtime, then these error indices are clustered into meta-action units garnered from the proposed function-motion-action structural decomposition method. The uncertainty information of these error indices are extracted by Shannon entropy to determine their objective weights, and their subjective weights are derived from AHP by the established function-motion-action-error hierarchical structure. Ultimately, the integrated weights of error indices and a sensitive analysis are employed to explore precision evaluation and precision life prediction of this milling machine, and a verification analysis using field data at different moments shows the rationality and reliability of the proposed approach.

We have developed a green and facile approach for the straightforward installation of isoindolinone skeletons via a tandem reaction of 2-cyanobenzaldehydes and α,β-unsaturated ketones/esters. In the presence of catalytic amounts of the organocatalyst, fluorous phosphine, in green solvents at rt, a variety of isoindolinones were obtained in good to excellent yields without tedious column chromatography. Moreover, both the catalyst and the solvents could be recycled, which greatly reduced the consumption and waste of resources. The simplicity of manipulation, high efficiency of resource utilization and environmentally benign characteristics enable this protocol to have broad applications in the synthesis of isoindolinones, especially those for drug discovery.

Synthesis of new functional organic molecules is a critical path that may greatly accelerate the evolution of organic optoelectronic materials. We have achieved a facile synthesis strategy to produce unique saddle-shaped multi-functional triazepinium salts that exhibit excellent solid-state fluorescence. Their fluorescence performance could be easily regulated by adjusting the dihedral angle between the main skeleton and the substituted moiety, giving a large Stokes shift, non-aggregation quenching, long lifetime, and multilevel-redox characteristics.

An electrochemical dehydrogenative [2 + 2 + 1] annulation used for the synthesis of imidazoles has been developed under undivided electrolytic conditions. In an undivided cell, aryl ketones and amines can smoothly participate in this transformation to furnish a variety of substituted imidazoles. The reaction avoids the use of both transition-metal catalysts and peroxide reagents, which makes it more sustainable and renewable.

The GLUT4 and PI3K/AKT signaling pathways are the key sensors of energy status and they regulate glucose and lipid metabolism. Phloretin activates the PI3K/AKT pathway by promoting GLUT4 translocation and expression, thereby improving glucose consumption and tolerance. As metformin can regulate glucose metabolism, we hypothesized that phloretin can amplify its gluco-regulatory effects. Male Sprague Dawley rats were fed with a high-fat and high-sugar diet for 8 weeks and injected with a low dose of streptozotocin to induce type 2 diabetes. The diabetic rats were randomized to receive phloretin (100 mg kg-1 d-1), metformin (250 mg kg-1 d-1), or phloretin + metformin via oral gavage for another 4 weeks. Random blood glucose, serum insulin, free fatty acid, total cholesterol, triglyceride, and low-density lipoprotein levels were detected in type 2 diabetic rats. Hematoxylin-eosin and Oil Red O staining were used to observe the pathological changes in the liver, pancreas, and adipose tissues of type 2 diabetic rats. The expression levels of IRS-1, PI3K, P-AKT, and GLUT4 in skeletal muscle were detected using western blotting. Phloretin plus metformin improved fasting blood glucose levels, glucose tolerance, and insulin sensitivity in type 2 diabetic rats. In addition, this combination reduced lipid accumulation, improved the pathological changes in the liver, pancreas, and adipose tissue, and increased IRS-1, PI3K, P-AKT, and GLUT4 expression in skeletal muscle and the liver of type 2 diabetic rats. Thus, phloretin can be used in a potential combination therapy with metformin for the prevention and rescue of type 2 diabetes.

A series of optically active α-aryloxy carboxylic acids were obtained via Chenphos/Rh catalyzed highly efficient asymmetric hydrogenation. The proposed ion-pairing interaction between the ligand and the substrate plays a vital role in achieving high enantioselectivity.

Resistance spot welding and hybrid weld bonding have wide applications in the body work construction within the automobile industry. The integrity of the spot welds and applied adhesives determines the body assembly rigidity and dynamic performance. Incorporating contact nonlinearity and geometric nonlinearity, finite element analysis (FEA) have been carried out to investigate the structural stiffness and strength of both spot-welded and weld-bonded assemblies. Topology optimization has been performed to reveal the distributions of material effectiveness in the overlap regions and suggest a feasible method for removing underutilized material for weight reduction. Design optimization has been conducted with an aim to reduce the maximum von Mises stress in the assembly to minimum by choosing optimum values for a set of design variables, including the weld spacing, weld diameter and overlap width.

The concept of process capability has been widely used in production management and quality control. However, applying traditional process capability evaluation method to machine capability cannot eliminate the influence of other process factors other than machine. To solve the problem, we propose the sigma machine capability evaluation method in this paper. First, multivariate statistical analysis methods are used to analyze the influence of all factors. Second, we deleted the non-normal data through sample fitting. Then, on the basis of normal distribution, we used the sample variance as the evaluation index to calculate the sigma levels of single characteristic and multiple characteristic parts. Last, we applied the sigma evaluation method and the traditional one to conduct a case study and compare their results, which proves the feasibility and superiority of the sigma level evaluation method.

Convenient synthesis and useful application of a series of Josiphos-type binaphane ligands were described. The iridium complexes of these chiral diphosphines displayed excellent enantioselectivity and good reactivity in the asymmetric hydrogenation of challenging 1-aryl-substituted dihydroisoquinoline substrates (full conversions, up to >99% ee, 4000 TON). The use of 40% HBr (aqueous solution) as an additive dramatically improved the asymmetric induction of these catalysts. This transformation provided a highly efficient and enantioselective access to chiral 1-aryl-substituted tetrahydroisoquinolines, which were of great importance and common in natural products and biologically active molecules.

BODIPY has been considered a potential scaffold because of their neutral total charge, sharp absorption, and emission with high fluorescence quantum yield. However, the drawback of emission wavelength at less than 600 nm and hydrophobicity limit its application. One of the extremely interesting properties of BODIPY is that small modifications to their structures could be able to tune their properties, mainly including the absorption/emission wavelength and the hydrophilicity. This review focuses on the modification at different positions of BODIPY to improve the water-solubility and emission wavelength that describe their spectral, photophysical properties and applicability, which is helpful for the researchers to rationally design BODIPY dyes to adapt a wide range of applications.

A tandem insertion of thiocyanate to enamine was performed for the regioselective synthesis of multisubstituted benzoimidazo[2,1-b]thiazoles. This method was shown to be effective in addressing the issue of isomerization encountered in common strategies. With a change made to the leading group on the aniline fragment of enamine, the reaction achieved different transformations, thus enabling multisubstituted benzo[4,5]imidazo[2,1-b]thiazoles and thiazoles in satisfactory yields.

We have developed a new type of n-pentenyl-type glycosides that can be activated by catalytic amounts of promoter, Hg(NTf2)2 or PPh3AuCl/AgNTf2, at room temperature. The mild activation conditions and outstanding stability of common protection/deprotection manipulations enable the enynyl donors to have broad applications in constructing various glycosidic bonds. Furthermore, under the Hg(NTf2)2-catalyzed conditions, the sequential activation of different types of donors was achieved, based on which a gentiotetrasaccharide was synthesized via the newly developed single-catalyst one-pot strategy.

Many high and steep slopes are formed in the open pit mining process, whose stability will directly affect the construction and safety. Therefore, it is particularly important to detect and eliminate rough errors of slope monitoring data. This paper proposes an improved two-layer extreme learning machine (TELM) based on particle swarm optimization (PSO) to establish monitoring slope model. In particular, the parameters of the first layer of the whole algorithm are obtained by particle swarm optimization algorithm, and the parameters of the second layer are calculated through a new solution method. First, some basic principles and concepts of extreme learning machine are introduced, and the algorithm thought, basic principles and related derivation of the improved two-layer extreme learning machine in this paper are emphatically discussed. A better mapping relationship between the input space and the output space is found through the parameter solution method, which improves the precision of the algorithm. Then, the data collection and traditional gross error elimination methods are studied. Finally, in order to test the ability of the two hidden layer extreme learning machine to solve the slope monitoring problem, the algorithm is applied to the gross error elimination of the slope data. The experimental results show that compared with the traditional gross error elimination method and ELM algorithm, the proposed method has higher precision, stronger robustness, and more practicability.