Convolutional neural networks (CNNs) have been applied to visual tasks since the late 1980s. However, despite a few scattered applications, they were dormant until the mid-2000s when developments in computing power and the advent of large amounts of labeled data, supplemented by improved algorithms, contributed to their advancement and brought them to the forefront of a neural network renaissance that has seen rapid progression since 2012. In this review, which focuses on the application of CNNs to image classification tasks, we cover their development, from their predecessors up to recent state-of-the-art deep learning systems. Along the way, we analyze (1) their early successes, (2) their role in the deep learning renaissance, (3) selected symbolic works that have contributed to their recent popularity, and (4) several improvement attempts by reviewing contributions and challenges of over 300 publications. We also introduce some of their current trends and remaining challenges.

Astragalus membranaceus is one of the most widely used traditional Chinese herbal medicines. It is used as immune stimulant, tonic, antioxidant, hepatoprotectant, diuretic, antidiabetic, anticancer, and expectorant. The current paper reviews the botanical characteristics, phytochemistry, and pharmacology of Astragali Radix. Information on Astragali Radix was gathered via the Internet (using Google Scholar, Baidu Scholar, Elsevier, ACS, Medline Plus, CNKI, and Web of Science) as well as from libraries and local books. More than 100 compounds, including flavonoids, saponins, polysaccharides, and amino acids, have so far been identified, and the various biological activities of the compounds have been reported. As an important traditional Chinese medicine, further studies on Astragali Radix can lead to the development of new drugs and therapies for various diseases. The improvement of its utilization should be studied further.

-2-Black phosphorus (P) is a layered material in which individual atomic layers of P are stacked together by weak van der Waals forces (similar to bulk graphite) 1 . Inside a single layer, each P atom is covalently bonded with three adjacent P atoms to form a corrugated plane of honeycomb structure (Fig. 1a, note top view of each crystal plane is in honeycomb structure). The three bonds take up all three valence electrons of P (different than graphene and graphite). This makes monolayer black P ('phosphorene') a semiconductor with a direct bandgap of ~2eV. The bandgap is reduced in few-layer phosphorene, and becomes ~0.3eV for bulk black P. 2,3,4,5,6,7,8 The bandgap and its dependence on thickness has brought mono-and few-layer phosphorene to the family of 2D crystals, especially for enabling field-effect transistors (FETs) 9,10,11,12 and optoelectronic devices with potential applications in the infrared regime, 13,14 with prototypes recently demonstrated.In parallel to its potential for making novel electronic and optoelectronic devices, black P possesses attractive mechanical properties that are unavailable in other peer materials: it has very large strain limit (30%), and is much more stretchable (Young's modulus of E Y =44GPa for single layer) than other layered materials (e.g., E Y =1TPa for graphene), especially in the armchair direction (x axis in Fig. 1a). 15Such superior mechanical flexibility, 15,16,17 together with the exotic negative Poisson's ratio 18 arising from its corrugated atomic planes, offers unique opportunities for effectively inducing and controlling sizable strains, and thus the electronic, optoelectronic, and thermoelectric properties in this nanomaterial. 19,20,21,22,23 For example, with a 2D tension (in N/m, as in surface tension) of 0. and frequency-shift-based resonant infrared sensors. 28To date, however, the exploration and implementation of black P mechanical devices have not yet been reported; such efforts have been plagued by the relative chemical activeness of black P:8 , 9 it can be readily oxidized in air, and the multiple processing steps (many involving wet chemistry) required in fabricating mechanical devices from layered 2D materials (lithography, metallization, etching and suspension, etc.) make it particularly challenging to preserve the quality of black P crystal throughout the process. Here, we make the initial experimental study on exploring and exploiting the mechanical properties of black P to realize the first robust black P crystalline nanomechanical devices, by employing a set of specially-engineered processing and measurement techniques. We fabricate suspended black P NEMS resonators with electrical contacts using a facile dry transfer technique, minimizing sample exposure to the ambient and completely avoiding chemical processes. We characterize the material properties in vacuum, and implement nanomechanical measurements on the black P NEMS resonators using a number of experimental schemes, including Brownian motion-induced thermomechanical resonance, elec...

The spines and bloom of cucumber (Cucumis sativus L.) fruit are two important quality traits related to fruit market value. However, until now, none of the genes involved in the formation of cucumber fruit spines and bloom trichomes has been identified. Here, the characterization of trichome development in wild-type (WT) cucumber and a spontaneous mutant, glabrous 1 (csgl1) controlled by a single recessive nuclear gene, with glabrous aerial organs, is reported. Via map-based cloning, CsGL1 was isolated and it was found that it encoded a member of the homeodomain-leucine zipper I (HD-Zip I) proteins previously identified to function mainly in the abiotic stress responses of plants. Tissue-specific expression analysis indicated that CsGL1 was strongly expressed in trichomes and fruit spines. In addition, CsGL1 was a nuclear protein with weak transcriptional activation activity in yeast. A comparative analysis of the digital gene expression (DGE) profile between csgl1 and WT leaves revealed that CsGL1 had a significant influence on the gene expression profile in cucumber, especially on genes related to cellular process, which is consistent with the phenotypic difference between csgl1 and the WT. Moreover, two genes, CsMYB6 and CsGA20ox1, possibly involved in the formation of cucumber trichomes and fruit spines, were characterized. Overall, the findings reveal a new function for the HD-Zip I gene subfamily, and provide some candidate genes for genetic engineering approaches to improve cucumber fruit external quality.