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Incorporation of CO into substrates to construct high‐value carbonyl compounds is an intensive industrial carbonylation procedure, however, high toxicity and wide explosion limits (12.5–74.0 vol% in air) of CO limit its application in industrial production. The development of a CO‐free catalytic system for carbonylation is one of ideal methods, but full of challenge. Herein, this study reports the CO‐free aminocarbonylation conversion of terminal alkynes synergistically catalyzed by a unique Co(ІІ)/Ag(І) metal–organic framework (MOF), in which the combination of isocyanides and O2 is employed as safe and green source of aminocarbonyl. This reaction has broad substrate applicability in terminal alkyne and isocyanides components with 100% atom economy. The bimetal MOF catalyst can be recycled at least five times without substantial loss of catalytic activities. Mechanistic investigations demonstrate that the synergistic effect between Ag(I) and Co(II) sites can efficiently activate terminal alkyne and isocyanides, respectively. Free radical capture experiments, FT‐IR analysis and theoretical explorations further reveal that terminal alkynes and isocyanides can be catalytically transformed into an anionic intermediate through heterolysis pathways. This work provides secure and practical access to carbonylation as well as a new approach to aminocarbonylation of terminal alkynes. This study proposes CO‐free aminocarbonylation of terminal alkynes catalyzed by a bimetallic Co(II)/Ag(І) metal–organic framework, along with 100% atom economy, safe aminocarbonyl source and mild condition. The excellent catalytic performance can be attributed to synergistic effect of Co(II)/Ag(І) metal–organic framework with modified Ag(І) sites and intrinsic Co(II) sites effectively activates substrates during catalytic reaction.

Background Previous research and published literature indicate that some patients with spinal diseases who underwent percutaneous transforaminal endoscopic decompression (PTED) still suffer some discomfort in the early recovery stage in the form of pain, stiffness, and swelling. These are usually considered minor residual symptoms or normal postoperative phenomenon (NPF) in the clinic, occur frequently, and are acknowledged by surgeons worldwide. To the best of our knowledge, we report the first case of a patient who had an osteoporotic vertebral fracture (OVF) misdiagnosed as NPF after she underwent PTED as a result of lumbar disc herniation (LDH). Case presentation A 71-year-old female with Parkinson’s disease who presented with lower back pain radiating to the legs was diagnosed as LDH in L4–5, after which a PTED of L4–5 was performed, with temporary alleviation of symptoms. However, severe lower back pain recurred. Unfortunately, the recurred pain initially misdiagnosed as NPF, in fact, was finally confirmed to be OVF by CT-scan. OVF in the early stage of post-PTED seldom occurs and is rarely reported in the literature. With a percutaneous vertebroplasty, the pain was significantly relieved, and she resumed walking. After 36-weeks of follow-up, the pain improved satisfactorily. Conclusion Doctors should not immediately diagnose a relapse of back pain following PTED as NPF, and hands-on careful physical and imaging examinations are necessary to manage recurring pain rightly and timely.

Street lighting, as the most essential and universal component of the urban lighting system, accounts for a large portion of public electricity usage. Therefore, improving street lamps working efficiency is vital for energy savings. This paper demonstrates the design of a smart street lighting system supported by the combination of NB-IoT and LoRa communication technology. By adopting an optimized street lamp control algorithm, the system can realize the automatic control of street lights according to the real-time traffic flow information. This system has been installed on Luyang Avenue, Lucheng City, Shanxi Province, China in May 2019. It managed to reduce the electricity consumption in this region significantly in June 2019, which was 18% lower than that in April 2019 and 19.7% lower than that in June 2018. By illustrating the unique advantages of this system in energy savings and cost reduction, this paper displays its potential for further application in the construction of smart cities on a large scale.

Cycloaddition of CO 2 with aziridines is an important reaction to obtain high-value products. Porous MOFs can catalyze this reaction, but co-catalysts are still necessary to improve the catalytic performance. Such a reaction catalyzed by MOFs-based materials without co-catalyst has not been reported hitherto. Herein, a porous and stable three-dimensional (3D) framework {[Ni(DCTP)]·6.5DMF} n ( 1 ) with a large Langmuir surface area of 3,789 m 2 /g was synthesized, which displayed high I 2 adsorption ability up to 731.0 mg/g and could release it reversibly. Additionally, it exhibited a high CO 2 adsorption capacity of 104.0 cm 3 /g at 273 K. The investigation results revealed 1 could effectively catalyze the cycloaddition of CO 2 and aziridines in the absence of additional co-catalyst, and it could maintain the catalytic activity after five cycles. Furthermore, 1 also exhibited high catalytic activity for the gram-scale experiment. Importantly, it is the first MOF material as a heterogeneous catalyst for the conversion of CO 2 and aziridines without co-catalyst.

In recent years, research on spatial scale and scale transformation of eroded sediment transport has become a forefront field in current soil erosion research, but there are very few studies on the scale effect problem in Karst regions of China. Here we quantitatively extracted five main factors influencing soil erosion, namely rainfall erosivity, soil erodibility, vegetative cover and management, soil and water conservation, and slope length and steepness. Regression relations were built between these factors and also the sediment transport modulus and drainage area, so as to initially analyze and discuss scale effects on sediment transport in the Wujiang River Basin （WRB）. The size and extent of soil erosion influencing factors in the WRB were gauged from： Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model （ASTER GDEM）, precipitation data, land use, soil type and Normalized Difference Vegetation Index （NDVI） data from Global Inventory Modeling and Mapping Studies （GIMMS） or Advanced Very High Resolution Radiometer （AVHRR）, and observed data from hydrometric stations. We find that scaling effects exist between the sediment transport modulus and the drainage area. Scaling effects are expressed after logarithmic transformation by a quadratic function regression relationship where the sediment transport modulus increases before decreasing, alongside changes in the drainage area. Among the five factors influencing soil erosion, slope length and steepness increases first and then decreases, alongside changes in the drainage area, and are the main factors determining the relationship between sediment transport modulus and drainage area. To eliminate the influence of scale effects on our results, we mapped the sediment yield modulus of the entire WRB, adopting a 1 000 km2 standard area with a smaller fitting error for all sub-basins, and using the common Kriging interpolation method.

Recent studies suggested that notochordal cells (NCs) and NC-conditioned medium (NCCM) can stimulate cell viability and matrix production of nucleus pulposus cells (NPCs). However, the potential of notochordal cell-rich nucleus pulposus (NRNP) incorporating the native environment of the intervertebral disc (IVD) has not been evaluated. The objective of this study was to develop an optimal NRNP model and test whether it can allow a significant level of NPC activation in vitro . Rabbit NRNP explants were divided into three groups according to different digestion time: digestion NRNP of 8 h, partial digestion NRNP of 2 h, and natural NRNP. Cell viability and NC phenotype were compared between these groups after 14 days of incubation. The products of the selected partial digestion NRNP group were then cocultured with human degenerated NPCs for 14 days. NPC viability, cell proliferation and senescence, the production of glycosaminoglycan (GAG) found in extracellular matrix, and NP matrix production by NPCs were assessed. The results showed that coculturing with partial digestion NRNP significantly improved the cell proliferation, cell senescence, and disc matrix gene expression of NPCs compared with those in the monoculture group. In addition, GAG/DNA ratio in the coculture group increased significantly, while the level of collagen II protein remained unchanged. In this study, we demonstrated that partial digestion NRNP may show a promising potential for NPC regeneration in IVD tissue engineering.

Based on the provincial units evaluation,this paper makes an assessment for sustainable developing capability of the integrated agricultural regionalization in China.At first ,an index system of agricultural sustainable development in China is built up,which includes 5 supporting subsystems of agricultural resources,agricultural develop-ment ,environment and ecosystem,rural society,sciences-esucation and management.We selected 95 factors on provin-cial level as basic indexes.Second,a relative assets/debt assessing method is used to gain relative net assets values (relative superiority) of every provincial unit,which are as supporting data for assessment.We also overlaid the Administra-tive Divisions Map of China and the Map of Integrated Agricultural Regionalization of China by Geography Information Sys-tem(GIS) to gain the area units of assessment.Third,according to the relative coherence principle of regionalization,we transform administration units to natural units through homogenizing all provincial relative net assets values in every agricultural assessing unit.After making order and grade,we complete the sustainable developing capability assessment to integrated agricultural regionalization in China.The assessing outcome shows that the total sustainable agricultural devdelop-ing capability of China is not high.Only about 1/3 in number or in area has reached the level of agricultural sustainable development.The relative net assets values exists a reducing trend from East China to West China.It needs a long period and great efforts to realize sustainable agricultural development over all China.Finally,there is a discussion to the study method.

Being simple, inexpensive, scalable and environmentally friendly, microporous biomass biochars have been attracting enthusiastic attention for application in lithium-sulfur （Li-S） batteries. Herein, porous bamboo biochar is activated via a KOH/annealing process that creates a microporous structure, boosts surface area and enhances electronic conductivity. The treated sample is used to encapsulate sulfur to prepare a microporous bamboo carbon-sulfur （BC-S） nanocomposite for use as the cathode for Li-S batteries for the first time. The BC-S nanocomposite with 50 wt.% sulfur content delivers a high initial capacity of 1,295 mA-h/g at a low discharge rate of 160 mA/g and high capacity retention of 550 mA-h/g after 150 cycles at a high discharge rate of 800 mA/g with excellent coulombic efficiency （995%）. This suggests that the BC-S nanocomposite could be a promising cathode material for Li-S batteries.

A two-phase model for the prediction of macrosegregation formed during solidification is presented. This model incorporates the descriptions of heat transfer, melt convection, solute transport, and solid movement on the system scale with microscopic relations for grain nucleation and growth. Then the model is used to simulate the solidification of a benchmark industrial 3.3-t steel ingot. Simulations are per- formed to investigate the effects of grain motion and pipe shrinkage formation on the final macrosegregation pattern. The model predictions are compared with experimental data and numerical results from literatures. It is demonstrated that the model is able to express the overall macrosegregation patterns in the ingot. Furthermore, the results show that it is essential to consider the motion of equiaxed grains and the formation of pipe shrinkage in modelling. Several issues for future model improvements are identified.

The advancement of technology in medicine has extended human life, but the lack of resource for the elderly care has also emerged. As people grow old, body functions will gradually decay, which causes the problem of inconvenience for the elderly, and even affect their ability to live independently. Therefore, how to effectively improve the mobility of the elderly is very important. Although many researches have been devoted to mobile assisted robots, seldom of them consider the comfort of pedestrians. We thus proposed a comfort-based guidance system for active walking helpers. The system can assist the user to move to the target location, while maintaining the comfort of them and also pedestrians during the process. Experiments are conducted to evaluate the feasibility of the system. Overall, our system is able to provide users with appropriate assistance, and makes them and pedestrians to feel more comfortable. We hope that the development of the proposed system can help the mobile assisted robot easier to b