637 research outputs found

    GS-IR: 3D Gaussian Splatting for Inverse Rendering

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    We propose GS-IR, a novel inverse rendering approach based on 3D Gaussian Splatting (GS) that leverages forward mapping volume rendering to achieve photorealistic novel view synthesis and relighting results. Unlike previous works that use implicit neural representations and volume rendering (e.g. NeRF), which suffer from low expressive power and high computational complexity, we extend GS, a top-performance representation for novel view synthesis, to estimate scene geometry, surface material, and environment illumination from multi-view images captured under unknown lighting conditions. There are two main problems when introducing GS to inverse rendering: 1) GS does not support producing plausible normal natively; 2) forward mapping (e.g. rasterization and splatting) cannot trace the occlusion like backward mapping (e.g. ray tracing). To address these challenges, our GS-IR proposes an efficient optimization scheme that incorporates a depth-derivation-based regularization for normal estimation and a baking-based occlusion to model indirect lighting. The flexible and expressive GS representation allows us to achieve fast and compact geometry reconstruction, photorealistic novel view synthesis, and effective physically-based rendering. We demonstrate the superiority of our method over baseline methods through qualitative and quantitative evaluations on various challenging scenes

    Analytic-Splatting: Anti-Aliased 3D Gaussian Splatting via Analytic Integration

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    The 3D Gaussian Splatting (3DGS) gained its popularity recently by combining the advantages of both primitive-based and volumetric 3D representations, resulting in improved quality and efficiency for 3D scene rendering. However, 3DGS is not alias-free, and its rendering at varying resolutions could produce severe blurring or jaggies. This is because 3DGS treats each pixel as an isolated, single point rather than as an area, causing insensitivity to changes in the footprints of pixels. Consequently, this discrete sampling scheme inevitably results in aliasing, owing to the restricted sampling bandwidth. In this paper, we derive an analytical solution to address this issue. More specifically, we use a conditioned logistic function as the analytic approximation of the cumulative distribution function (CDF) in a one-dimensional Gaussian signal and calculate the Gaussian integral by subtracting the CDFs. We then introduce this approximation in the two-dimensional pixel shading, and present Analytic-Splatting, which analytically approximates the Gaussian integral within the 2D-pixel window area to better capture the intensity response of each pixel. Moreover, we use the approximated response of the pixel window integral area to participate in the transmittance calculation of volume rendering, making Analytic-Splatting sensitive to the changes in pixel footprint at different resolutions. Experiments on various datasets validate that our approach has better anti-aliasing capability that gives more details and better fidelity.Comment: 29 page

    Disproportionately Elevated Proinsulin Levels as an Early Indicator of β

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    Disproportionately Elevated Proinsulin Levels as an Early Indicator of -Cell Dysfunction in Nondiabetic Offspring of Chinese Diabetic Patients

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    Objective. To study the characteristics of -cell dysfunction and insulin resistance (IR) in the first-degree relatives (FDRs) of T2DM in Chinese population and to examine the usefulness of proinsulin (PI) for evaluating -cell dysfunction. Methods. 229 subjects of nondiabetic FDRs, 71 newly diagnosed T2DM, and 114 with normal glucose tolerance (NGT) but not FDRs (NGT-non-FDRs) were verified by a 2-hour oral glucose tolerance test. Specific insulin (SI) and PI were measured by highly sensitive ELISA. Results. Compared to NGT-non-FDRs, NGT-FDRs showed higher levels of fasting and 2-hour PI, fasting PI-to-SI ratio (FPI/SI), and HOMA-IR ( < 0.01). Meanwhile, fasting PI, FPI/SI, and HOMA-IR were increased steadily from NGT-FDRs to prediabetesFDRs and were highest in T2DM group ( < 0.001), whereas a significant decrease in HOMA-B could be observed only in T2DM group. Moreover, a progressive deterioration of -cell function in NGT-FDRs, prediabetes-FDRs, and T2DM could be identified by FPI/SI even after adjusting for HOMA-IR: relative to non-FDRs controls, mean FPI/SI levels were increased 1.5, 2.0, and 4.7-fold, respectively (all < 0.01). Conclusions. -cell dysfunction as assessed by disproportionate secretion of proinsulin and IR by HOMA (using specific insulin assay) already exist in FDRs of T2DM even with normal glucose status. Compared with HOMA-B, FPI/SI could detect -cell failure in earlier stage of diabetes development

    Effect of Corilagin on the Proliferation and NF- κ

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    Background. This study is to explore the effect of corilagin on the proliferation and NF-κB signaling pathway in U251 glioblastoma cells and U251 glioblastoma stem-like cells. Methods. CD133 positive U251 glioblastoma cells were separated by immunomagnetic beads to isolate glioblastoma stem-like cells. U251 cells and stem-like cells were intervened by different corilagin concentrations (0, 25, 50, and 100 μg/mL) for 48 h, respectively. Cell morphology, cell counting kit-8 assay, flow cytometry, dual luciferase reporter assay, and a western blot were used to detect and analyze the cell proliferation and cell cycle and investigate the expression of IKBα protein in cytoplasm and NF-κB/p65 in nucleus. Results. Corilagin inhibited the cell proliferation of U251 cells and their stem-like cells and the inhibition role was stronger in U251 stem-like cells (P<0.05). The cell cycle was arrested at G2/M phase in the U251 cells following corilagin intervention; the proportion of cells in G2/M phase increased as the concentration of corilagin increased (P<0.05). The U251 stem-like cells were arrested at the S phase following treatment with corilagin; the proportion of cells in the S phase increased as the concentration of corilagin increased (P<0.05). The ratio of dual luciferase activities of U251 stem-like cells was lower than that of U251 cells in the same corilagin concentration. With increasing concentrations of corilagin, the IKBα expression in cytoplasm of U251 cells and U251 stem-like cells was increased, but the p65 expression in nucleus of U251 cells and U251 stem-like cells was decreased (P<0.05). Conclusion. Corilagin can inhibit the proliferation of glioblastoma cells and glioblastoma stem-like cells; the inhibition on glioblastoma stem-like cell proliferation is stronger than glioblastoma cells. This different result indicates that the effect of corilagin on U251 cells and U251 stem-like cells may have close relationships with mechanism of cell cycle and NF-κB signaling pathway; however, the real antitumor mechanism of corilagin is not yet clear and requires further study

    Realization of the tradeoff between internal and external entanglement

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    We experimentally realize the internal and external entanglement tradeoff, which is a new kind of entanglement monogamy relation different from that usually discussed. Using a source of twin photons, we find that the external entanglement in polarization of twin photons, and the path-polarization internal entanglement of one photon, limit each other. In the extreme case, when the internal state is maximally entangled, the external entanglement must be vanishing, that illustrate entanglement monogamy. Our results of the experiment coincide with the theoretical predictions, and therefore provide a direct experimental observation of the internal and external entanglement monogamy relation.Comment: 10 pages, 7 figure

    A Picrorhiza kurroa

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    Background. Free radicals and proinflammatory cytokines have been shown to play a critical role in the pathogenesis of ulcerative colitis (UC). Picroliv, a Picrorhiza kurroa derivative, has been demonstrated to have antioxidant and anti-inflammatory effect. The purpose of the study was to investigate the effects of picroliv on experimental model of UC in mice. Materials and Methods. Picroliv was administrated orally by gavage to mice with colitis induced by dextran sulfate sodium (DSS). Disease activity index (DAI), colon length, and histology score were observed. Myeloperoxidase (MPO) activity, and SOD, MDA concentrations were measured by enzyme-linked immunosorbent assay (ELISA) while the expression of cytokine mRNAs was studied by real-time-quantitative polymerase chain reaction and also ELISA. The expression of NF-κB p65 was observed by immunohistochemistry staining and western blotting. Results. A significant improvement was observed in DAI and histological score in mice treated with picroliv, and incerased MPO activity, MDA concentrations, and the expression of IL-1β, TNF-α, and NF-κB p65 in mice with DSS-induced colitis were significantly reduced while decreased SOD level increased following administration of picroliv. Conclusion. The administration of picroliv leads to an amelioration of DSS-induced colitis, suggesting administration of picroliv may provide a therapeutic approach for UC
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