Coumarin skeletons are significant structural units frequently used in the fields of synthetic chemistry, medicinal chemistry, and materials science. Herein, we report a hemilabile P,N-ligand-assisted gold-catalyzed difunctionalization of activated alkynes with organohalides. The reaction occurs effectively under mild conditions without requiring an external oxidant, producing a variety of 3-arylated and alkenylated coumarin derivatives in high to excellent yields.
View Article and Find Full Text PDFIntercropping medicinal plants plays an important role in agroforestry that can improve the physical, chemical, and biological fertility of soil. However, the influence of intercropping medicinal plants on the soil properties and bacterial communities remains elusive. In this study, five intercropping treatment groups were set as follows: / (EZ), / (JH), / (YDC), / (HDK), and / (WZMT).
View Article and Find Full Text PDFFront Comput Neurosci
April 2024
In recent years, with the rapid development of network applications and the increasing demand for high-quality network service, quality-of-service (QoS) routing has emerged as a critical network technology. The application of machine learning techniques, particularly reinforcement learning and graph neural network, has garnered significant attention in addressing this problem. However, existing reinforcement learning methods lack research on the causal impact of agent actions on the interactive environment, and graph neural network fail to effectively represent link features, which are pivotal for routing optimization.
View Article and Find Full Text PDFThe epiphytic and endophytic bacteria play an important role in the healthy growth of plants. Both plant species and growth environmental influence the bacterial population diversity, yet it is inconclusive whether it is the former or the latter that has a greater impact. To explore the communities of the epiphytic and endophytic microbes in Camellia oleifera, this study assessed three representative C.
View Article and Find Full Text PDFThis paper considers the interactive effects between the ego vehicle and other vehicles in a dynamic driving environment and proposes an autonomous vehicle lane-changing behavior decision-making and trajectory planning method based on graph convolutional networks (GCNs) and multi-segment polynomial curve optimization. Firstly, hierarchical modeling is applied to the dynamic driving environment, aggregating the dynamic interaction information of driving scenes in the form of graph-structured data. Graph convolutional neural networks are employed to process interaction information and generate ego vehicle's driving behavior decision commands.
View Article and Find Full Text PDFBackground: miR390s is an ancient family with a high level of conservation among plant miRNAs. Through the auxin signal transduction pathway, miR390 participates in diverse biological processes of plant growth and development. As an important Chinese traditional orchid, Cymbidium goeringii has unique flower shape and elegant fragrance.
View Article and Find Full Text PDFBackground: is an economically important genus of flowering orchids cultivated in China because of showing graceful leaf shapes and elegant flower coloration. However, the deterioration of the ecological environment and the difficulty of conservation management have become increasing challenges for maintaining its germplasm resources. ARFs are critical transcription factors in the auxin signaling pathway and have been found to play pivotal roles in leaf growth and development in previous studies.
View Article and Find Full Text PDFBackground: Chinese bayberry (Myrica rubra Sieb. & Zucc.) is an important fruit tree in China, and has high medicinal value.
View Article and Find Full Text PDFA general visible-light-promoted metal-free synthesis of secondary and tertiary thiocarbamates starting from thiosulfonates and -substituted formamides is developed. By employing rhodamine B as a photocatalyst and -butyl hydroperoxide (TBHP) as an oxidant, a wide scope of thiocarbamates can be obtained through direct thiolation of acyl C-H bonds under irradiation of blue light at room temperature for 12 h.
View Article and Find Full Text PDFObjectives: To investigate the effect of compression factor on visual performance in orthokeratology (ortho-k).
Methods: Myopic adults were fitted with ortho-k lenses with either a 0.75 diopter (D) or 1.
This paper presents a multi-band terahertz superabsorber with a surface structure that consists of a square metallic patch with a very small rectangular hole whose area is only 3.94% of the square patch. The introduction of a rectangular hole in the square patch plays an important role in achieving multi-band absorption.
View Article and Find Full Text PDFEndophytic bacteria, which are common in plant tissues, may help to control plant pathogens and enhance plant growth. Camellia oleifera, an oil-producing plant, is widely grown in warm, subtropical, hilly regions in China. However, C.
View Article and Find Full Text PDFSichuan Da Xue Xue Bao Yi Xue Ban
January 2020
Objective: To study the changes of tear film after short-term overnight orthokeratology wearing in adult myope.
Methods: Fifty adult myope aged 18 to 38 years old were enrolled in this study. The patients wore orthokeratology 6-10 h every night during this study.
A dual-band terahertz metamaterial absorber composed of two identical square metallic patches and an insulating medium layer on top of a continuous metallic ground is demonstrated. Two resonance peaks (labeled A and B) with near 100% absorbance are obtained, of which peak A derived from the localized resonance of the two square patches has a line-width of 0.2571 THz and quality factor of 6.
View Article and Find Full Text PDFBroadband metamaterial absorbers are of critical importance in practical applications, but their obtainment approaches are quite complex at present. We demonstrate here that a fairly simple structure design formed by a rectangular-shaped resonator having an elongated slot can be utilized to achieve a broadband absorption response at terahertz frequencies. More than 50% absorption in a continuous frequency range of 1.
View Article and Find Full Text PDFA terahertz metamaterial resonator consisting of two rectangular strips embedded in a closed-ring resonator is designed and investigated in this paper that can simultaneously generate the classical electromagnetically induced transparency effect and two Fano resonance modes. The formation of the transparent window and the Fano dips can be attributed to the coupling of the localized resonance modes between the closed-ring resonator and the two embedded rectangular strips. The effect of embedded rectangular strip sizes on the transmitted performance is discussed, and it is found that the resonant performance of the transparent window and Fano effect depends mainly on the length of the rectangular strips in the longitudinal direction.
View Article and Find Full Text PDFThis paper gives the design of electromagnetically induced transparency effect using two U-shaped resonators with different opening directions (same direction and opposite direction). It is revealed that extremely similar transparency effect can be found for the two cases. The reason is that the two structures have the same sizes.
View Article and Find Full Text PDFNanoscale Res Lett
February 2019
Various kinds of structure designs have been proposed to achieve the multiple-band metamaterial absorbers. However, the discrete distance of adjacent frequencies of multiple absorbers is considerably large, which will inevitably overlook a large amount of information hidden in the off-resonance absorption areas. Herein, a narrow discrete distance of dual-band terahertz absorber based on two pairs of an Au strip/dielectric layer backed by Au film is designed.
View Article and Find Full Text PDFConvolutional neural networks (CNNs) are powerful tools for image segmentation and classification. Here, we use this method to identify and mark the heart region of Drosophila at different developmental stages in the cross-sectional images acquired by a custom optical coherence microscopy (OCM) system. With our well-trained CNN model, the heart regions through multiple heartbeat cycles can be marked with an intersection over union of ~86%.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
June 2014
In order to study the function of soil microfauna and its responses to environmental changes, we used metagenome analyses of the 18S rDNA gene region to identify differences in microfauna diversity and community structure among fifteen soil samples belonging to five different Cunninghamia lanceolate plantations. The plantations were located in Youxian County, Hunan Province in central China. The trees in these plantations were of different ages (3, 13, and 26 years) and belonged to different ecological successions (first, second, and third successions).
View Article and Find Full Text PDFBiotechnol Biotechnol Equip
March 2014
Plackett-Burman design and Box-Behnken response surface methodology (RSM) was employed to optimize the medium components for the chitin deacetylase (CDA) activity from Z7. Plackett-Burman design was applied to determine the specific medium components affecting CDA activity and found that starch, chitin and MgSO were critical in augmenting CDA activity. These significant parameters were further optimized using Box-Behnken RSM and the optimum concentrations of starch, chitin and MgSO were found to be 24.
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