2,078 research outputs found

    A Dynamic Steganography Method for Web Images with Average RunLength-Coding

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    Web page has many redundancies, especially the dynamic html multimedia object. This paper proposes a novel method to employ the commonly used image elements on web pages. Due to the various types of image format and complexity of image contents and their position information, secret message bits could be coded to embed in these complex redundancies. Together with a specific covering code called average run-length-coding, the embedding efficiency could be reduced to a low level and the resulting capacity outperforms traditional content-based image steganography, which modifies the image data itself and causes a real image quality degradation. Our experiment result demonstrates that the proposed method has limited processing latency and high embedding capacity. What’s more, this method has a low algorithm complexity and less image quality distortion compared with existing steganography methods

    The role of mononuclear phagocyte system in IgA nephropathy: pathogenesis and prognosis

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    Although the “multiple hits” theory is a widely accepted pathogenesis in IgA nephropathy (IgAN), increasing evidence suggests that the mononuclear/macrophage system plays important roles in the progression of IgAN; however, the exact mechanism is unclear. In the present study, we explored 1,067 patients in 15 studies and found that the number of macrophages per glomerulus was positively related with the degree of hematuria, and the macrophages in the glomeruli were mainly related to mesangial proliferation (M) in renal biopsy. In the tubulointerstitium, macrophages were significantly paralleled to tubulointerstitial α-SMA and NF-kB expression, tubulointerstitial lesion, tubule atrophy/interstitial fibrosis (T), and segmental glomerulosclerosis (S). In the glomeruli and tubulointerstitium, M1 accounted for 85.41% in the M classification according to the Oxford MEST-C, while in the blood, M1 accounted for 100%, and the patients with low CD89+ monocyte mean fluorescence intensity displayed more severe pathological characteristics (S1 and T1-2) and clinical symptoms. M1 (CD80+) macrophages were associated with proinflammation in the acute phase; however, M2 (CD163+) macrophages participated in tissue repair and remodeling, which correlated with chronic inflammation. In the glomeruli, M2 macrophages activated glomerular matrix expansion by secreting cytokines such as IL-10 and tumor necrosis factor-β (TGF-β), and M0 (CD68+) macrophages stimulated glomerular hypercellularity. In the tubulointerstitium, M2 macrophages played pivotal roles in renal fibrosis and sclerosis. It is assumed that macrophages acted as antigen-presenting cells to activate T cells and released diverse cytokines to stimulate an inflammatory response. Macrophages infiltrating glomeruli destroy the integrity of podocytes through the mesangio-podocytic-tubular crosstalk as well as the injury of the tubule

    Martensitic Phase Transformations in Fe-Co-Ni-Pd-Pt Multicomponent Alloys

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    Fe70Pd30 and Fe75Pt25 alloys exhibit complex ordering and martensitic transformations close to room temperature leading to varied shape memory and superelasticity effects that can be both strain and magnetically induced. High entropy alloys are a relatively new class of multicomponent alloys that when carefully designed can exhibiting property improvement and tailorability compared to less complex conventional alloys. The major objective of this thesis is to utilise these new high entropy alloy concepts and through the incremental compositional modification of the Fe70Pd30 and Fe75Pt25 shape memory alloys understand the effect of individual element addition and substitution on martensitic phase transformations in Fe-Co-Ni-Pt-Pd alloys. Two reported base alloys Fe70Pd30 and Fe75Pt25 were manufactured, homogenised and water-quenched and found to exhibit significant BCC-type and BCT-type martensitic and FCC (austenitic) phase transformations by differential scanning calorimetry and X-ray diffraction experiments. Following this, a series of ternary alloys were produced to examine the incremental effects of Ni, Co, Pd, and Pt addition or substitution on the martensitic transformation of these two base alloys. Upon thermal cycling, the BCT martensitic crystal structure, as opposed to BCC structure, was observed in all ternary alloys that exhibited a martensitic transformation. Elemental additions that maintained martensitic and austenitic transformation events were all found to decrease the martensitic transformation temperature and increase the austenitic transformation temperature compared to the base alloys. Based on these results, a series of quaternary alloys were produced to examine the combined effects of elemental additions. Results showed that none of the Fe70Pd30-based quaternary alloys displayed a martensitic transformation. Fe75Pt25-based quaternary alloys exhibited martensitic and austenitic transformations and the product of the martensitic transformation was BCC rather than the BCT crystal structure. Based on these results a select few quinary alloys were produced, with only the Fe70Co5Ni2.5Pd2.5Pt20 alloy exhibiting both a martensitic and austenitic transformation, however in this case the observed martensite had a BCC crystal structure rather than the previously observed BCT structure. Overall, the martensitic transformations observed in the multicomponent variants of the Fe70Pd30 and Fe75Pt25 alloys are very sensitive to compositional change, which was proposed to be due to only specific element substitution on specific lattice sites supporting the transformation, which in many cases, the volume fraction of martensite produced, and energy associated with the transformation diminished with substitution. This tends to point to the conclusion that compositional and crystal lattice structural entropy may be less advantageous for highly specific structural transformations

    Optimization of Proteasomal Degradation Reporter (eDeg-On) System for CRISPR-mediated Whole-genome Knockout Screens

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    Protein folding and clearance of misfolded proteins are crucial to maintain cellular homeostasis (Jariel-Encontre et al., 2008). Misfolded proteins may associate with other cellular components and possibly impair their functions. They may also self-associate to form insoluble aggregates, which are the hallmarks of a number of neurodegenerative diseases, such as Parkinson’s (Olanow and McNaught, 2006) and Alzheimer’s (Oddo, 2008). The ubiquitin proteasome system (UPS) is the main pathway that catalyzes the degradation of soluble misfolded proteins in mammalian cells. Therefore, enhancing the UPS activity through activation of proteasomal degradation is considered a promising strategy to ameliorate phenotypes associated with the accumulation of misfolded proteins. Modulation of specific UPS components, for instance, results in increased degradation of target proteins (Rechsteiner and Hill, 2005 and Vilchez et al., 2012). However, our current understanding of the molecular mechanism underlying proteasomal degradation is still limited, limiting the rational design of pharmacologic strategies to enhance UPS activity. As a result, proteasome activators are rare and remain poorly characterized (Huang and Chen, 2009). To overcome these limitations, researchers in my group developed a cell-based platform (the eDeg-On system) to monitor changes in UPS activity. This genetic circuit links increase in UPS activity to an increase in fluorescent output, thereby providing a reliable tool for the discovery of proteasome activators. The CRISPR-cas technology has emerged as powerful technique to introduce genetic modifications at the whole-genome scale. I optimized the eDeg-On system and evaluated it for pooled screening of whole-genome CRISPR-mediated knockout library. I replaced the antibiotic resistance gene in the eDeg-On system and assessed the response of HEK293 cells stably expressing the eDeg-On system to modulation of proteasomal degradation. To evaluate the use of a stable cell line expressing the eDeg-On system as a reporter assay in the context of a pooled CRISPR-mediated screen, I conducted mock screens using different ratios of positive and negative controls. The results obtained demonstrate that the eDeg-On system can be used as a reporter assay for CRISPR-mediated whole-genome knockout screens. The use of the eDeg-On system to conduct genetic screen for the discovery of molecules that function as proteasome regulators will contribute to the development of therapeutic strategies for protein misfolding diseases. Further applications of this study include targeting the UPS function for therapeutic applications as well as for enhancing the production of recombinant proteins in industrial settings

    Perchlorate, nitrate, and sulfate reduction in hydrogen-based membrane biofilm reactor : model-based evaluation

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    © 2017 Elsevier B.V. A biofilm model was developed to evaluate the key mechanisms including microbially-mediated ClO4−, NO3−, and SO42−reduction in the H2-based membrane biofilm reactor (MBfR). Sensitivity analysis indicated that the maximum growth rate of H2-based denitrification (μ1) and maximum growth rate of H2-based SO42−reduction (μ3) could be reliably estimated by fitting the model predictions to the experimental measurements. The model was first calibrated using the experimental data of a single-stage H2-based MBfR fed with different combinations of ClO4−, NO3−, and/or SO42−together with a constant dissolved oxygen (DO) concentration at three operating stages. μ1and μ3were determined at 0.133 h−1and 0.0062 h−1, respectively, with a good level of identifiability. The model and the parameter values were further validated based on the experimental data of a two-stage H2-based MBfR system fed with ClO4−, NO3−, SO42−, and DO simultaneously but at different feeding rates during two running phases. The validated model was then applied to evaluate the quantitative and systematic effects of key operating conditions on the reduction of ClO4−, NO3−, and SO42−as well as the steady-state microbial structure in the biofilm of a single-stage H2-based MBfR. The results showed that i) a higher influent ClO4−concentration led to a higher ClO4−removal efficiency, compensated by a slightly decreasing SO42−removal; ii) the H2loading should be properly managed at certain critical level to maximize the ClO4−and NO3−removal while limiting the growth of sulfate reducing bacteria which would occur in the case of excessive H2supply; and iii) a moderate hydraulic retention time and a relatively thin biofilm were required to maintain high-level removal of ClO4−and NO3−but restrict the SO42−reduction

    Fast generation of arbitrary optical focus array

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    We report a novel method to generate arbitrary optical focus arrays (OFAs). Our approach rapidly produces computer-generated holograms (CGHs) to precisely control the positions and the intensities of the foci. This is achieved by replacing the fast Fourier transform (FFT) operation in the conventional iterative Fourier-transform algorithm (IFTA) with a linear algebra one, identifying/removing zero elements from the matrices, and employing a generalized weighting strategy. On the premise of accelerating the calculation speed by >70 times, we demonstrate OFA with 99% intensity precision in the experiment. Our method proves effective and is applicable for the systems in which real-time OFA generation is essential

    Optimal map-making with singularities

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    In this work, we investigate the optimal map-making technique for the linear system d=Ax+n\bm{d}=\bm{A}\bm{x}+\bm{n} while carefully taking into account singularities that may come from either the covariance matrix C=$orthemainmatrix\bm{C} = \$ or the main matrix \bm{A}$. We first describe the general optimal solution, which is quite complex, and then use the modified pseudo inverse to create a near-optimal solution, which is simple, robust, and can significantly alleviate the unwanted noise amplification during map-making. The effectiveness of the nearly optimal solution is then compared to that of the naive co-adding solution and the standard pseudo inverse solution, showing noticeable improvements. Interestingly, all one needs to get the near-optimal solution with singularity is just a tiny change to the traditional optimal solution that is designed for the case without singularity.Comment: 24 pages, 7 figures, and 2 appendice
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