69 research outputs found

    A Machine Vision Method for Correction of Eccentric Error: Based on Adaptive Enhancement Algorithm

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    In the procedure of surface defects detection for large-aperture aspherical optical elements, it is of vital significance to adjust the optical axis of the element to be coaxial with the mechanical spin axis accurately. Therefore, a machine vision method for eccentric error correction is proposed in this paper. Focusing on the severe defocus blur of reference crosshair image caused by the imaging characteristic of the aspherical optical element, which may lead to the failure of correction, an Adaptive Enhancement Algorithm (AEA) is proposed to strengthen the crosshair image. AEA is consisted of existed Guided Filter Dark Channel Dehazing Algorithm (GFA) and proposed lightweight Multi-scale Densely Connected Network (MDC-Net). The enhancement effect of GFA is excellent but time-consuming, and the enhancement effect of MDC-Net is slightly inferior but strongly real-time. As AEA will be executed dozens of times during each correction procedure, its real-time performance is very important. Therefore, by setting the empirical threshold of definition evaluation function SMD2, GFA and MDC-Net are respectively applied to highly and slightly blurred crosshair images so as to ensure the enhancement effect while saving as much time as possible. AEA has certain robustness in time-consuming performance, which takes an average time of 0.2721s and 0.0963s to execute GFA and MDC-Net separately on ten 200pixels 200pixels Region of Interest (ROI) images with different degrees of blur. And the eccentricity error can be reduced to within 10um by our method

    New contributions to the knowledge of Chinese flea beetle fauna (III): revision of Meishania Chen & Wang with description of five new species (Coleoptera: Chrysomelidae: Galerucinae)

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    The flea beetle genus Meishania Chen & Wang is revised and five new species—M. cangshanensis sp. nov., M. flavipen- nis sp. nov., M. fulvotigera sp. nov., and M. sichuanica sp. nov. from China and M. bhutanensis sp. nov. from Bhutan— are described. All species of Meishania are illustrated and a key to species is provided

    New contributions to the knowledge of Chinese flea beetle fauna (III): revision of Meishania Chen & Wang with description of five new species (Coleoptera: Chrysomelidae: Galerucinae)

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    The flea beetle genus Meishania Chen & Wang is revised and five new species—M. cangshanensis sp. nov., M. flavipen- nis sp. nov., M. fulvotigera sp. nov., and M. sichuanica sp. nov. from China and M. bhutanensis sp. nov. from Bhutan— are described. All species of Meishania are illustrated and a key to species is provided

    Geometric morphometric analysis of the pronotum and elytron in stag beetles: insight into its diversity and evolution

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    Stag beetles (Coleoptera, Scarabaeoidea, Lucanidae) have received extensive attention from researchers in behavioral ecology and evolutionary biology. There have been no previous quantitative analyses, particularly using a geometric morphometric approach based on a large sample of data, to shed light on the morphological diversity and evolution of Lucanidae. Thoracic adaptation and ecological differentiation are intimately related, and the pronotum bears important muscles and supports the locomotion of prothoracic legs. The elytron is an autapomorphy of the Coleoptera. To reconstruct and visualize the patterns of evolutionary diversification and phylogenetic history of shape change, an ancestral groundplan can be reconstructed by mapping geometric morphometric data onto a phylogenetic tree. In this study, the morphologies of the pronotum and elytron in 1303 stag beetles (Lucanidae), including approximately 99.2% of all globally described species, were examined, thus revealing several aspects of morphological diversity and evolution. First, on the basis of geometric morphometric analysis, we found significant morphological differences in the pronotum or elytron between any two Lucanidae subfamilies. And we subsequently reconstructed the ancestral groundplans of the two structures in stag beetles and compared them with those of extant species (through cladistic and geometric morphometric methods). The ancestral groundplan of Lucanidae was found to be most similar to extant Nicagini in both the pronotum and elytron, according to Mahalanobis distances. Furthermore, we analyzed species richness and morphological diversity of stag beetles and the relationships between them and found that the two parameters were not always correlated. Aesalinae was found to be the most diverse subfamily in both the pronotum and elytron, despite its poor species richness, and the diversity of the pronotum or elytron was not superior in Lucaninae, despite its high species richness. Our study provides insights into the morphological variations and evolutionary history of the pronotum and elytron in four subfamilies of stag beetles, and it illuminates the relationship between morphological diversity and species richness. Intriguingly, our analysis indicates that morphological diversity and species richness are not always correlated. These findings may stimulate further studies in this field

    The jumping mechanism of flea beetles (Coleoptera, Chrysomelidae, Alticini), its application to bionics and preliminary design for a robotic jumping leg

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    Flea beetles (Coleoptera, Chrysomelidae, Galerucinae, Alticini) are a hyperdiverse group of organisms with approximately 9900 species worldwide. In addition to walking as most insects do, nearly all the species of flea beetles have an ability to jump and this ability is commonly understood as one of the key adaptations responsible for its diversity. Our investigation of flea beetle jumping is based on high-speed filming, micro- CT scans and 3D reconstructions, and provides a mechanical description of the jump. We reveal that the flea beetle jumping mechanism is a catapult in nature and is enabled by a small structure in the hind femur called an ‘elastic plate’ which powers the explosive jump and protects other structures from potential injury. The explosive catapult jump of flea beetles involves a unique ‘high-efficiency mechanism’ and ‘positive feedback mechanism’. As this catapult mechanism could inspire the design of bionic jumping limbs, we provide a preliminary design for a robotic jumping leg, which could be a resource for the bionics industry

    The Lysosomal v-ATPase-Ragulator Complex Is a Common Activator for AMPK and mTORC1, Acting as a Switch between Catabolism and Anabolism

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    林圣彩教授课题组长期致力于细胞信号转导的研究。近年来,该课题组潜心研究,不断攻关,取得了一系列重大成果,如揭示细胞如何应对生长因子缺乏的内在机理,发现了细胞自噬“路线图”、还发现了细胞如何感应“饥饿”信号AMP的信号传导通路等。其中,“发现细胞自噬‘路线图’”成果曾登上《科学》杂志,并入选2012年度“中国科学十大进展”。AMPK and mTOR play principal roles in governing metabolic programs; however, mechanisms underlying the coordination of the two inversely regulated kinases remain unclear. In this study we found, most surprisingly, that the late endosomal/lysosomal protein complex v-ATPase-Ragulator, essential for activation of mTORC1, is also required for AMPK activation. We also uncovered that AMPK is a residential protein of late endosome/lysosome. Under glucose starvation, the v-ATPase-Ragulator complex is accessible to AXIN/LKB1 for AMPK activation. Concurrently, the guanine nucleotide exchange factor (GEF) activity of Ragulator toward RAG is inhibited by AXIN, causing dissociation from endosome and inactivation of mTORC1. We have thus revealed that the v-ATPase-Ragulator complex is also an initiating sensor for energy stress and meanwhile serves as an endosomal docking site for LKB1-mediated AMPK activation by forming the v-ATPase-Ragulator-AXIN/LKB1-AMPK complex, thereby providing a switch between catabolism and anabolism. Our current study also emphasizes a general role of late endosome/lysosome in controlling metabolic programs

    Successful treatment with bortezomib in combination with dexamethasone in a middle-aged male with idiopathic multicentric Castleman’s disease: A case report

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    Multicentric Castleman disease (MCD) is a heterogeneous, life-threatening disease. A subgroup of HIV-negative and HHV-8-negative MCD is defined as idiopathic MCD (iMCD) with a poor prognosis. Here we report an unusual case of a 47-year-old male patient with iMCD who experienced multiple treatment regimens such as chemotherapy, immunomodulatory therapy, and targeted therapy, all of which were considered ineffective. Subsequently, he was started on bortezomib in combination with dexamethasone for six cycles and he was in complete remission. The patient has survived nearly 13 years to date – the longest survival of any iMCD patient treated with bortezomib in combination with dexamethasone. Bortezomib combined with dexamethasone may be an effective salvage strategy for severe and refractory iMCD

    Optical Element Surface Defect Size Recognition Based on Decision Regression Tree

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    Defect size recognition is significant to the evaluation of optical element surface quality. Currently, it’s mainly achieved by the conventional image process, such as threshold segmentation. However, as the defect size gradually approaches the diffraction limit of the imaging system, the defect gray distribution changes from bimodal to unimodal, which makes it difficult to be accurately recognized. In this paper, an electromagnetic simulation model of the microscopic scattering dark-field imaging (MSDI) system is built based on the finite-difference time-domain (FDTD) method to research the defect imaging mechanism. The point spread function (PSF) of our MSDI system is measured to revise the far-field simulation light intensity distribution, and the mean value of the distance between three groups of feature points, whose intensity is 0.75, 0.5, and 0.25 of the light intensity distribution peak value, is taken as the feature parameter of the light intensity distribution. To obtain the defect size, the decision regression tree (DRT) is proposed to get the relationship between the feature parameter and the defect size. Besides, some scratches samples are made to verify the validity of the DRT. The results show the relative error of DRT is within 10%, which is better than the threshold segmentation

    A review of the genus Lankaphthona Medvedev, 2001, with comments on the modified phallobase and the unique abdominal appendage of L. binotata (Baly) (Coleoptera, Chrysomelidae, Galerucinae, Alticini)

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    The flea beetle genus Lankaphthona Medvedev, 2001 is redescribed and a new species L. yunnantarsella sp. nov. Ruan, Konstantinov & Prathapan is described. Longitarsella Medvedev, 2009, syn. nov. and Philotarsa Medvedev, 2009, syn. nov. are newly synonymized with Lankaphthona. Philotarsa laosica Medvedev, 2009, syn. nov. is synonymized with Lankaphthona phuketensis (Gruev, 1989). The following new combinations are proposed: Lankaphthona binotata (Baly, 1876), comb. nov.; Lankaphthona costata (Medvedev, 2016), comb. nov.; Lankaphthona cyanipennis (Medvedev, 2017), comb. nov.; Lankaphthona nigronotata (Jacoby, 1896), comb. nov.; Lankaphthona notatipennis (Medvedev, 2009), comb. nov.; and Lankaphthona phuketensis (Gruev, 1989), comb. nov., status restored. A highly specialized spoon-shaped ‘appendage’ is discovered on the first abdominal ventrite of males of Lankaphthona binotata. Aedeagus of the same species has aberrant sheath-shaped phallobase encircling the median lobe. Morphology and possible function of these structures are discussed. Menispermaceae are newly reported as the host plants of the genus
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