51 research outputs found

    Infrared carpet cloak designed with uniform silicon grating structure

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    Through a particularly chosen coordinate transformation, we propose an optical carpet cloak that only requires homogeneous anisotropic dielectric material. The proposed cloak could be easily imitated and realized by alternative layers of isotropic dielectrics. To demonstrate the cloaking performance, we have designed a two-dimensional version that a uniform silicon grating structure fabricated on a silicon-on-insulator wafer could work as an infrared carpet cloak. The cloak has been validated through full wave electromagnetic simulations, and the non-resonance feature also enables a broadband cloaking for wavelengths ranging from 1372 to 2000 nm.Comment: 11 pages, 4 figure

    Fully Automatic Karyotyping via Deep Convolutional Neural Networks

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    Chromosome karyotyping is an important yet labor-intensive procedure for diagnosing genetic diseases. Automating such a procedure drastically reduces the manual work of cytologists and increases congenital disease diagnosing precision. Researchers have contributed to chromosome segmentation and classification for decades. However, very few studies integrate the two tasks as a unified, fully automatic procedure or achieved a promising performance. This paper addresses the gap by presenting: 1) A novel chromosome segmentation module named ChrRender, with the idea of rendering the chromosome instances by combining rich global features from the backbone and coarse mask prediction from Mask R-CNN; 2) A devised chromosome classification module named ChrNet4 that pays more attention to channel-wise dependencies from aggregated informative features and calibrating the channel interdependence; 3) An integrated Render-Attention-Architecture to accomplish fully automatic karyotyping with segmentation and classification modules; 4) A strategy for eliminating differences between training data and segmentation output data to be classified. These proposed methods are implemented in three ways on the public Q-band BioImLab dataset and a G-band private dataset. The results indicate promising performance: 1) on the joint karyotyping task, which predicts a karyotype image by first segmenting an original microscopical image, then classifying each segmentation output with a precision of 89.75% and 94.22% on the BioImLab and private dataset, respectively; 2) On the separate task with two datasets, ChrRender obtained AP50 of 96.652% and 96.809% for segmentation, ChrNet4 achieved 95.24% and 94.07% for classification, respectively. The COCO format annotation files of BioImLab used in this paper are available at https://github.com/Alex17swim/BioImLab The study introduces an integrated workflow to predict a karyotyping image from a Microscopical Chromosome Image. With state-of-the-art performance on a public dataset, the proposed Render-Attention-Architecture has accomplished fully automatic chromosome karyotyping

    RUC-Net: A Residual-Unet-Based Convolutional Neural Network for Pixel-Level Pavement Crack Segmentation

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    Automatic crack detection is always a challenging task due to the inherent complex backgrounds, uneven illumination, irregular patterns, and various types of noise interference. In this paper, we proposed a U-shaped encoder–decoder semantic segmentation network combining Unet and Resnet for pixel-level pavement crack image segmentation, which is called RUC-Net. We introduced the spatial-channel squeeze and excitation (scSE) attention module to improve the detection effect and used the focal loss function to deal with the class imbalance problem in the pavement crack segmentation task. We evaluated our methods using three public datasets, CFD, Crack500, and DeepCrack, and all achieved superior results to those of FCN, Unet, and SegNet. In addition, taking the CFD dataset as an example, we performed ablation studies and compared the differences of various scSE modules and their combinations in improving the performance of crack detection

    Identification of a novel COL1A1 frameshift mutation, c.700delG, in a Chinese osteogenesis imperfecta family

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    Osteogenesis imperfecta (OI) is a family of genetic disorders associated with bone loss and fragility. Mutations asso-ciated with OI have been found in genes encoding the type I collagen chains. People with OI type I often produce in-sufficient 1-chain type I collagen because of frameshift, nonsense, or splice site mutations in COL1A1 or COL1A2. This report is of a Chinese daughter and mother who had both experienced two bone fractures. Because skeletal fra-gility is predominantly inherited, we focused on identifying mutations in COL1A1 and COL1A2 genes. A novel muta-tion in COL1A1, c.700delG, was detected by genomic DNA sequencing in the mother and daughter, but not in their relatives. The identification of this mutation led to the conclusion that they were affected by mild OI type I. Open read-ing frame analysis indicated that this frameshift mutation would truncate 1-chain type I collagen at residue p263 (p.E234KfsX264), while the wild-type protein would contain 1,464 residues. The clinical data were consistent with the patients ’ diagnosis of mild OI type I caused by haploinsufficiency of 1-chain type I collagen. Combined with previous reports, identification of the novel mutation COL1A1-c.700delG in these patients suggests that additional genetic and environmental factors may influence the severity of OI

    New Approach for Single-Step Extraction of Carboxylated Cellulose Nanocrystals for Their Use As Adsorbents and Flocculants

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    A simple approach was developed to isolate cellulose nanocrystals (CNCs) with carboxylic groups from microcrystalline cellulose (MCC). The effect of reaction time on the morphology, microstructure, and thermal stability of isolated CNCs was investigated. The rod-like CNCs with size of 200–250 nm in length and about 15–20 nm in width were obtained by one-step citric/hydrochloric acid (C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>/HCl) hydrolysis of MCC. The CNCs extracted at 4 h showed the highest carboxylic group content which led to a high absolute zeta potential value up to 46.63 mV. Moreover, these CNCs may be used as cationic dye adsorbent (methylene blue) and efficient flocculants with excellent coagulation–flocculation capability to kaolin suspension with a turbidity removal of 99.5%
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