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A method is proposed to determine the cone-beam x-ray acquisition geometry of an imaging system using a phantom consisting of discrete x-ray opaque markers defining two parallel rings sharing a common axis. The phantom generates a...
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A method is proposed to determine the cone-beam x-ray acquisition geometry of an imaging system using a phantom consisting of discrete x-ray opaque markers defining two parallel rings sharing a common axis. The phantom generates an image of two ellipses which are fitted to an ellipse model. A phantom-centric coordinate system is used to simplify the equations describing the ellipse coefficients such that a solution describing the acquisition geometry can be obtained via numerical optimization of only three of the nine unknown variables. We perform simulations to show how errors in the fit of the ellipse coefficients affect estimates of the acquisition geometries. These simulations show that for ellipse projections sampled with 1200 markers, 25 microm errors in marker positions and a source-detector distance (SDD) of 1.6 m, we can measure angles describing detector rotation with a mean error of <0.002 degrees and a standard deviation (SD) of <0.03 degrees. The SDD has a mean error of 0.004 mm and SD = 0.24 mm. The largest error is associated with the determination of the point on the detector closest to the x-ray source (mean error = 0.05 mm, SD = 0.85 mm). A prototype phantom was built and results from x-ray experiments are presented.
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This report provides a perspective on metabolic glycoengineering methodology developed over the past two decades that allows natural sialic acids to be replaced with chemical variants in living cells and animals. Examples are give...
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This report provides a perspective on metabolic glycoengineering methodology developed over the past two decades that allows natural sialic acids to be replaced with chemical variants in living cells and animals. Examples are given demonstrating how this technology provides the glycoscientist with chemical tools that are beginning to reproduce Mother Nature's control over complex biological systems - such as the human brain - through subtle modifications in sialic acid chemistry. Several metabolic substrates (e.g., ManNAc, Neu5Ac, and CMP-Neu5Ac analogs) can be used to feed flux into the sialic acid biosynthetic pathway resulting in numerous - and sometime quite unexpected - biological repercussions upon nonnatural sialoside display in cellular glycans. Once on the cell surface, ketone-, azide-, thiol-, or alkyne-modified glycans can be transformed with numerous ligands via bioorthogonal chemoselective ligation reactions, greatly increasing the versatility and potential application of this technology. Recently, sialic acid glycoengineering methodology has been extended to other pathways with analog incorporation now possible in surface-displayed GalNAc and fucose residues as well as nucleocytoplasmic O-GlcNAc-modified proteins. Finally, recent efforts to increase the "druggability" of sugar analogs used in metabolic glycoengineering, which have resulted in unanticipated "scaffold-dependent" activities, are summarized.
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Clusterin (CLU) is a multivalent glycoprotein with ubiquitous tissue distribution. To address the possible differential functional roles assumed by different isoforms of CLU in the progression of human ovarian cancer, we construct...
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Clusterin (CLU) is a multivalent glycoprotein with ubiquitous tissue distribution. To address the possible differential functional roles assumed by different isoforms of CLU in the progression of human ovarian cancer, we constructed 2 human ovarian cancer cell models that represent examples of contradistinctive CLU expression levels. One is constitutively overexpressing different clusterin isoforms in SKOV3 cells by transfection of the 3 different expression vectors, another is silencing the intrinsically expressing clusterin in cisplatin-resistant human A2780-cis(CP70) tumor cells with the usage of shRNA-mediated CLU gene silencing. Then, the different cellular localization, biological effects, and functional roles played in tumor progression and drug resistances were studied. We found that (i) in the distinct cellular contexts of human ovarian carcinoma SKOV3 and CP70 cells assayed, sCLU is a central molecule in cell homeostasis that functions as a cytoprotective protein, whereas nCLU is proapoptotic; (ii) In SKOV3 cells, nuclear localization of the truncated CLU is NLS dependent, without which the pnCLU protein was sequestrated in cytoplasm to prevent cytotoxicity. (iii) sCLU plays a significant role in the development of the chemoresistance phenotype in ovarian cancer cells. Moreover, with the CLU-specific shRNA oligonucleotides, we successfully sensitized cells for chemotherapy, and inhibited cells' proliferation, migration and invasion. Collectively, our results reveal that, CLU gene expression might play a crucial role in ovarian cancer progression, adaptation and eventual resistance to chemotherapy through differential processing of CLU isoforms. Specifically, sCLU as an antiapoptotic protein, upregulated in an adaptive cell-survival manner by chemotherapy, confers resistance to various cell-death triggers.
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To find new anti-thrombotic agents, a natural amino acid was introduced into the 3-position of anti-platelet aggregation active 3S-tetrahydroisoquinoline-3-carboxylic acid (THIQA), and 20 novel dipeptide derivatives, 3S-tetrahydro...
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To find new anti-thrombotic agents, a natural amino acid was introduced into the 3-position of anti-platelet aggregation active 3S-tetrahydroisoquinoline-3-carboxylic acid (THIQA), and 20 novel dipeptide derivatives, 3S-tetrahydroisoquinoline-3-carboxyamino acids (6a-t), targeting the intestinal peptide transport system were provided. In vitro anti-platelet aggregation assay of 6a-t indicated that their potencies of inhibiting adenosine diphosphate (ADP), arachidonic acid (AA), platelet-activating factor (PAF), and thrombin (TH) induced platelet aggregations were higher than that of THIQA, and the in vivo anti-thrombotic assay of 6a-t indicated that their potencies of inhibiting thrombogenesis in rats were also higher than that of THIQA. According to MFA based Cerius2 QSAR module, using training/test set of 6a,b,d,g-p/6c,e,f,q and training/test set of 6a-p/6q-t, two equations (r, 0.984 and 0.996) correlating the structures with in vitro or in vivo activity of 6a-t were established.
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A number of efforts had been sought to instrument bridges for the purpose of structural monitoring and assessment. The outcome of these efforts, as gauged by advances in the understanding of the definition of structural damage and...
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A number of efforts had been sought to instrument bridges for the purpose of structural monitoring and assessment. The outcome of these efforts, as gauged by advances in the understanding of the definition of structural damage and their role in sensor selection as well as in the design of cost and data-effective monitoring systems, has itself been difficult to assess. The authors' experience with the design, calibration, and operation of a monitoring system for the Kishwaukee Bridge in Illinois has provided several lessons that bear upon these concerns. The systems have performed well in providing a continuous, low-cost monitoring platform for bridge engineers with immediate relevant information.
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This paper presents a new approach for solving accurate approximate analytical higher-order solutions for strong nonlinear Duffing oscillators with cubic-quintic nonlinear restoring force. The system is conservative and with odd n...
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This paper presents a new approach for solving accurate approximate analytical higher-order solutions for strong nonlinear Duffing oscillators with cubic-quintic nonlinear restoring force. The system is conservative and with odd non-linearity. The new approach couples Newton's method with harmonic balancing. Unlike the classical harmonic balance method, accurate analytical approximate solutions are possible because linearization of the governing differential equation by Newton's method is conducted prior to harmonic balancing. The approach yields simple linear algebraic equations instead of nonlinear algebraic equations without analytical solution. Using the approach, accurate higher-order approximate analytical expressions for period and periodic solution are established. These approximate solutions are valid for small as well as large amplitudes of oscillation. In addition, it is not restricted to the presence of a small parameter such as in the classical perturbation method. Illustrative examples are presented to verify accuracy and explicitness of the approximate solutions. The effect of strong quintic nonlinearity on accuracy as compared to cubic nonlinearity is also discussed.
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Traditional information hiding algorithms cannot maintain a good balance of capacity, invisibility and robustness. In this paper, a novel blind colour image information hiding algorithm based on grey prediction and grey relational...
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Traditional information hiding algorithms cannot maintain a good balance of capacity, invisibility and robustness. In this paper, a novel blind colour image information hiding algorithm based on grey prediction and grey relational analysis in the Discrete Cosine Transform (DCT) domain is proposed. First, this algorithm compresses the secret image losslessly based on the improved grey prediction GM(1,1) (IGM) model. It then chooses the blocks of rich texture in the cover image as the embedding regions using Double-dimension Grey Relational Analysis (DGRA). Finally, it adaptively embeds the compressed secret bits stream into the DCT domain mid-frequency coefficients, which are decided by those blocks' Double-Dimension Grey Correlation Degree (DGCD) and Human Visual System (HVS). This method can ensure an adequate balance between invisibility, capacity and robustness. Experimental results show that the proposed algorithm is robust against JPEG compression (46.724 6 dB when the compression quality factor is 90%), Gaussian noise (45.531 3 dB when the parameter is (0,0.000 5)) etc., and it is a blind information hiding algorithm that can be extracted without an original carrier.
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Aiming to efficiently support the Locator/Identifier Separation Protocol (LISP), in this paper, we present an enhanced pointer-based DHT mapping system: LISP-PCHORD. The system creates a pointer space to build on top of standard D...
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Aiming to efficiently support the Locator/Identifier Separation Protocol (LISP), in this paper, we present an enhanced pointer-based DHT mapping system: LISP-PCHORD. The system creates a pointer space to build on top of standard DHTs. Mappings within the pointer space are (Endpoint Identifiers (EID), pointers) where the pointer is the address of the root node (the physical node that stores the mappings) of the corresponding (EID, Routing Locators (RLOCs)) mappings. In addition to enabling architectural qualities such as scalability and reliability, the proposed LISP-PCHORD can copy with flat EIDs such as self-certifying EIDs. The performance of the mapping system plays a key role in LISP; however, DHT-based approaches for LISP seldom consider the mismatch problem that heavily damages the system performance in terms of lookup latency. In order to mitigate the mismatch problem and achieve optimal performance, we propose an optimization design method that seeks an optimal matching relationship between P-nodes (nodes within the pointer space) and the physical nodes on the basis of the given lookup traffic matrix. In order to find the optimal matching relationship, we provide two solutions: a linear programming method and a genetic algorithm. Finally, we evaluate the performance of the proposed scheme and compare it with that of LISP-DHT.
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Alopecia areata (AA) is an autoimmune disease that presents as nonscarring hair loss, although the exact pathogenesis of the disease remains to be clarified. Disease prevalence rates from 0.1% to 0.2% have been estimated for the U...
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Alopecia areata (AA) is an autoimmune disease that presents as nonscarring hair loss, although the exact pathogenesis of the disease remains to be clarified. Disease prevalence rates from 0.1% to 0.2% have been estimated for the United States. AA can affect any hair-bearing area. It often presents as well demarcated patches of nonscarring alopecia on skin of overtly normal appearance. Recently, newer clinical variants have been described. The presence of AA is associated with a higher frequency of other autoimmune diseases. Controversially, there may also be increased psychiatric morbidity in patients with AA. Although some AA features are known poor prognostic signs, the course of the disease is unpredictable and the response to treatment can be variable. Part one of this two-part series on AA describes the clinical presentation and the associated histopathologic picture. It also proposes a hypothesis for AA development based on the most recent knowledge of disease pathogenesis. LEARNING OBJECTIVES: After completing this learning activity, participants should be familiar with the most recent advances in AA pathogenesis, recognize the rare and recently described variants of AA, and be able to distinguish between different histopathologic stages of AA.
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Various therapeutic agents have been described for the treatment of alopecia areata (AA), but none are curative or preventive. The aim of AA treatment is to suppress the activity of the disease. The high rate of spontaneous remiss...
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Various therapeutic agents have been described for the treatment of alopecia areata (AA), but none are curative or preventive. The aim of AA treatment is to suppress the activity of the disease. The high rate of spontaneous remission and the paucity of randomized, double-blind, placebo-controlled studies make the evidence-based assessment of these therapies difficult. The second part of this two-part series on AA discusses treatment options in detail and suggests treatment plans according to specific disease presentation. It also reviews recently reported experimental treatment options and potential directions for future disease management. LEARNING OBJECTIVES: After completing this learning activity, participants should be able to compare the efficacy and safety of various treatment options, formulate a treatment plan tailored to individual patients, and recognize recently described treatments and potential therapeutic approaches.
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