364 research outputs found

    A concrete certificateless signature scheme without pairings

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    Certificateless public key cryptography was introduced to avoid the inherent key escrow problem in identity-based cryptography, and eliminate the use of certificates in traditional PKI. Most cryptographic schemes in certificateless cryptography are built from bilinear mappings on elliptic curves which need costly operations. Despite the investigation of certificateless public key encryption without pairings, certificateless signature without pairings received much less attention than what it deserves. In this paper, we present a concrete pairing-free certificateless signature scheme for the first time. Our scheme is more computationally efficient than others built from pairings. The new scheme is provably secure in the random oracle model assuming the hardness of discrete logarithm problem

    The thickness of the ventral medial prefrontal cortex predicts the prior-entry effect for allocentric representation in near space

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    Neuropsychological studies have demonstrated that the preferential processing of near-space and egocentric representation is associated with the self-prioritization effect (SPE). However, relatively little is known concerning whether the SPE is superior to the representation of egocentric frames or near-space processing in the interaction between spatial reference frames and spatial domains. The present study adopted the variant of the shape-label matching task (i.e., color-label) to establish an SPE, combined with a spatial reference frame judgment task, to examine how the SPE leads to preferential processing of near-space or egocentric representations. Surface-based morphometry analysis was also adopted to extract the cortical thickness of the ventral medial prefrontal cortex (vmPFC) to examine whether it could predict differences in the SPE at the behavioral level. The results showed a significant SPE, manifested as the response of self-associated color being faster than that of stranger-associated color. Additionally, the SPE showed a preference for near-space processing, followed by egocentric representation. More importantly, the thickness of the vmPFC could predict the difference in the SPE on reference frames, particularly in the left frontal pole cortex and bilateral rostral anterior cingulate cortex. These findings indicated that the SPE showed a prior entry effect for information at the spatial level relative to the reference frame level, providing evidence to support the structural significance of the self-processing region

    Sox10+ adult stem cells contribute to biomaterial encapsulation and microvascularization.

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    Implanted biomaterials and biomedical devices generally induce foreign body reaction and end up with encapsulation by a dense avascular fibrous layer enriched in extracellular matrix. Fibroblasts/myofibroblasts are thought to be the major cell type involved in encapsulation, but it is unclear whether and how stem cells contribute to this process. Here we show, for the first time, that Sox10+ adult stem cells contribute to both encapsulation and microvessel formation. Sox10+ adult stem cells were found sparsely in the stroma of subcutaneous loose connective tissues. Upon subcutaneous biomaterial implantation, Sox10+ stem cells were activated and recruited to the biomaterial scaffold, and differentiated into fibroblasts and then myofibroblasts. This differentiation process from Sox10+ stem cells to myofibroblasts could be recapitulated in vitro. On the other hand, Sox10+ stem cells could differentiate into perivascular cells to stabilize newly formed microvessels. Sox10+ stem cells and endothelial cells in three-dimensional co-culture self-assembled into microvessels, and platelet-derived growth factor had chemotactic effect on Sox10+ stem cells. Transplanted Sox10+ stem cells differentiated into smooth muscle cells to stabilize functional microvessels. These findings demonstrate the critical role of adult stem cells in tissue remodeling and unravel the complexity of stem cell fate determination

    NQO1 targeting prodrug triggers innate sensing to overcome checkpoint blockade resistance

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    Lack of proper innate sensing inside tumor microenvironment (TME) limits T cell-targeted immunotherapy. NAD(P)H:quinone oxidoreductase 1 (NQO1) is highly enriched in multiple tumor types and has emerged as a promising target for direct tumor-killing. Here, we demonstrate that NQO1-targeting prodrug β-lapachone triggers tumor-selective innate sensing leading to T cell-dependent tumor control. β-Lapachone is catalyzed and bioactivated by NQO1 to generate ROS in NQO1high tumor cells triggering oxidative stress and release of the damage signals for innate sensing. β-Lapachone-induced high mobility group box 1 (HMGB1) release activates the host TLR4/MyD88/type I interferon pathway and Batf3 dendritic cell-dependent cross-priming to bridge innate and adaptive immune responses against the tumor. Furthermore, targeting NQO1 is very potent to trigger innate sensing for T cell re-activation to overcome checkpoint blockade resistance in well-established tumors. Our study reveals that targeting NQO1 potently triggers innate sensing within TME that synergizes with immunotherapy to overcome adaptive resistance

    Sparse Representation Based Binary Hypothesis Model for Hyperspectral Image Classification

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    The sparse representation based classifier (SRC) and its kernel version (KSRC) have been employed for hyperspectral image (HSI) classification. However, the state-of-the-art SRC often aims at extended surface objects with linear mixture in smooth scene and assumes that the number of classes is given. Considering the small target with complex background, a sparse representation based binary hypothesis (SRBBH) model is established in this paper. In this model, a query pixel is represented in two ways, which are, respectively, by background dictionary and by union dictionary. The background dictionary is composed of samples selected from the local dual concentric window centered at the query pixel. Thus, for each pixel the classification issue becomes an adaptive multiclass classification problem, where only the number of desired classes is required. Furthermore, the kernel method is employed to improve the interclass separability. In kernel space, the coding vector is obtained by using kernel-based orthogonal matching pursuit (KOMP) algorithm. Then the query pixel can be labeled by the characteristics of the coding vectors. Instead of directly using the reconstruction residuals, the different impacts the background dictionary and union dictionary have on reconstruction are used for validation and classification. It enhances the discrimination and hence improves the performance

    Grammatical and contextual factors affecting the interpretation of superordinate collectives in child and adult Mandarin

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    The semantics of superordinate collectives (superordinates hereafter) such as English furniture are argued to be count or mass, or to allow both count and mass readings. When tested experimentally, however, it has repeatedly been reported that superordinates denote individuals in a wide range of typologically distinct languages, including Mandarin. A close examination of the experimental method and design commonly used in previous research suggests, however, that the attested individual-denoting reading might only be the preferred reading in neutral contexts rather than the only reading that superordinates allow. In the present study, using a Truth Value Judgment Task we investigate the interpretation of Mandarin superordinates by Mandarin-speaking adults and 4–6-year-old children. We found that bare superordinates can convey both individual-denoting and non-individual-denoting readings depending on specific contexts provided, but such contextual manipulation cannot override morphosyntax (the presence of an individual classifier that selects an individual-denoting reading only). Taken together, our experimental data indicate that both contextual and morphosyntactic information play an important role in the interpretation of Mandarin superordinates, but that they function in different ways. In a word, the present study contributes new data and opens new perspectives for further investigation in the interpretation of superordinates in Mandarin as well as in other languages

    Discovering Temporal Associations among Significant Changes in Gene Expression

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    Abstract-One of the most demanding problems in mining temporal data is to identify how multivariate change associations might be discovered and used to better understand data interactions and dependencies. This paper introduces a framework to mine associations among significant changes in multivariate time-series data. Building on statistical methods, we detect significant changes in timeseries data and use marginal change rates to qualify the direction of change at significant change points. Furthermore, a propositional confirmation-guided rule discovery method is used to discover associations among these significant changes. We apply our approach to gene expression data measured in yeast cell cycles and demonstrate that our method can learn novel and highquality significant change associations among different genes. Such associations can be used to cluster genes and build gene interaction networks
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