15 research outputs found

    Image generation with shortest path diffusion

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    The field of image generation has made significant progress thanks to the introduction of Diffusion Models, which learn to progressively reverse a given image corruption. Recently, a few studies introduced alternative ways of corrupting images in Diffusion Models, with an emphasis on blurring. However, these studies are purely empirical and it remains unclear what is the optimal procedure for corrupting an image. In this work, we hypothesize that the optimal procedure minimizes the length of the path taken when corrupting an image towards a given final state. We propose the Fisher metric for the path length, measured in the space of probability distributions. We compute the shortest path according to this metric, and we show that it corresponds to a combination of image sharpening, rather than blurring, and noise deblurring. While the corruption was chosen arbitrarily in previous work, our Shortest Path Diffusion (SPD) determines uniquely the entire spatiotemporal structure of the corruption. We show that SPD improves on strong baselines without any hyperparameter tuning, and outperforms all previous Diffusion Models based on image blurring. Furthermore, any small deviation from the shortest path leads to worse performance, suggesting that SPD provides the optimal procedure to corrupt images. Our work sheds new light on observations made in recent works and provides a new approach to improve diffusion models on images and other types of data.Comment: AD and SF contributed equall

    Application of thermosensitive-hydrogel combined with dental pulp stem cells on the injured fallopian tube mucosa in an animal model

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    Objectives: Fallopian tube (FT) injury is an important factor that can lead to tubal infertility. Stem-cell-based therapy shows great potential for the treatment of injured fallopian tube. However, little research has shown that mesenchymal stem cells (MSCs) can be used to treat fallopian tube damage by in situ injection. In this study, we in situ transplanted PF127 hydrogel encapsulating dental pulp stem cells (DPSCs) into the injured sites to promote the repair and regeneration of fallopian tube injury.Materials and methods: The properties of dental pulp stem cells were evaluated by flow cytometry, immunofluorescence analysis, and multi-differentiation detection. The immunomodulatory and angiogenic characteristics of dental pulp stem cells were analyzed on the basis of the detection of inflammatory factor expression and the formation of capillary-like structures, respectively. The biocompatibility of PF127 hydrogel was evaluated by using Live/Dead and CCK-8 assays. The effects of PF127 hydrogel containing dental pulp stem cells on the repair and regeneration of fallopian tube injury were evaluated by histological analysis [e.g., hematoxylin and eosin (H&E) and Masson’s trichrome staining, TUNEL staining, immunofluorescence staining, and immunohistochemistry], Enzyme-linked immunosorbent assay (ELISA), and RT-PCR detections.Results: Dental pulp stem cells had MSC-like characteristics and great immunomodulatory and angiogenic properties. PF127 hydrogel had a thermosensitive feature and great cytocompatibility with dental pulp stem cells. In addition, our results indicated that PF127 hydrogel containing dental pulp stem cells could promote the repair and regeneration of fallopian tube damage by inhibiting cell apoptosis, stimulating the secretion of angiogenic factors, promoting cell proliferation, modulating the secretion of inflammatory factors, and restoring the secretion of epithelial cells.Conclusion: In this study, our results reported that in situ injection of PF127 hydrogel encapsulating dental pulp stem cells into the injured sites could provide an attractive strategy for the future treatment of fallopian tube injury in clinical settings

    Development of xenon level instrumentation for the LZ dark matter detector

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    Galactical and cosmological evidence show that a quarter of the energy budget of our universe is made of collisionless, non-relativistic, and non-baryonic dark matter. Its potential coupling to standard model particles, however, has not yet been understood. One of the leading candidates - Weakly Interacting Massive Particles (WIMP) - allows the production of a dark matter relic density as observed today and couples to standard model particles at or below the weak scale. LUX-ZEPLIN (LZ) is a future tonne-scale two-phase xenon TPC aiming to detect WIMP recoils with xenon nuclei. The experiment will begin WIMP search data-taking in 2020 at the Sanford Underground Research Facility (SURF) in Lead, South Dakota and has a projected sensitivity of 3 × 10-48 cm2 or better in probing a 40 GeV/c2 WIMP. The main observables of particle interactions in LZ are the primary scintillation (S1) and secondary scintillation (S2). However, optimising and achieving a stable S2 signal in such a tonne-scale TPC is non-trivial. Effects from the structural design of the S2 production region (top-corner structure), TPC tilt, and the xenon circulation system requires precise monitoring of the liquid surface. Such monitoring is achieved by the capacitive liquid level sensors developed within this thesis. The sensors are strategically placed to ensure that nonuniformity of the S2 signal due to the effects can be understood and corrected. In this thesis, the development of a monitoring system designed to optimise the quality of the S2 signal, based on the capacitive level sensors is discussed. A design of the electronics scheme based on a differential measurement allows femtofarad precision measurement of sensor’s capacitance at picofarad level, even in the presence of cable capacitance at nanofarad level. A systematic study of the response of such a sensor to LXe and the application of the precision level sensors to two-phase TPC was carried out. Findings of intrinsic influences from LXe artefacts and LXe dielectric constant variation with its saturated temperature are identified; the result on the application of the sensors contributes to the designs of LZ circulation and the top-corner region. The final LZ level sensors show an artefact-free liquid level measurement and a 12 μm precision in measuring liquid nitrogen level (projection for LXe: &amp;Tilde; 9 μm) over a 20 mm measurement range.</p

    Design Optimization and Carbon Footprint Analysis of an Electrodeionization System with Flexible Load Regulation

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    Thermal power plants will function as a flexible load regulation in a low-carbon grid, which requires operation adaption for the whole system. Energy transition in the electricity sector is the core to realizing carbon neutrality. The power grid will be gradually dominated by renewable energy, such as wind power and photovoltaic solar power. However, renewable energy has problems such as insufficient power supply and output fluctuation; thermal power will be required to regulate the peak load flexibly to meet demand. Therefore, the supply of boiler make-up water prepared by electrodeionization (EDI) in thermal power plants should also be flexibly changed. This study focused on the ultrapure water preparation system by EDI with variable flow rates. For an EDI system with a maximum ultrapure water capacity of 20 m3/h, the power consumption, annual cost, and carbon footprint of different designs are compared. The operation parameters were optimized based on the optimal cost design when the temporal demand of boiler make-up water is reduced to 75%, 50%, and 25%, respectively, considering thermal power as peak load regulation technology. The results showed that the optimized system could significantly reduce power consumption and carbon footprint by up to 30.21% and 30.30%, respectively. The proposed strategy is expected to be widely applied for design and operation optimization when considering the low-carbon but unstable energy system dominated by renewable energy. The carbon footprint could be a feasible optimization object to balance the greenhouse gas emissions from the module manufacturing and operation consumption

    A Novel Strategy for the Design of Aurein 1.2 Analogs with Enhanced Bioactivities by Conjunction of Cell-Penetrating Regions

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    The rational design modification of membrane-active peptide structures by introducing additional membrane-penetrating regions has become a good strategy for the improvement of action and potency. Aurein 1.2 (GLFDIIKKIAESF-NH2) is a multifunctional antimicrobial peptide isolated from the green and golden bell frog, Litoria aurea, and the southern bell frog Litoria raniformis skin secretions. Its bio-functionality has been widely investigated. However, its lack of a potent action failed to provide aurein 1.2 with a competitive edge for further development as a therapeutic agent for clinical use. Herein, aurein 1.2 was chosen as a template for rational modification to achieve a more potent bio-functionality. KLA-2 (GLFDIIKKLAKLAESF-NH2), which a double KLA region inserted into the sequence, presented a 2–16-fold enhancement of antimicrobial activity, a 2–8-fold greater anti-biofilm activity (including biofilm prevention and eradication), and a 7-fold more potent anti-proliferation activity and hence was regarded as the most broad-spectrum active peptide. Additionally, with respect to antimicrobial activity, the IIKK-modified analog, IK-3 (GLFDIIKKIIKKIIKKI-NH2), also demonstrated a potent enhancement of activity against various pathogens, exhibiting a 2–8-fold enhanced activity compared to the parent peptide. Moreover, the selectivities of KLA-1 and KLA-2 were enhanced significantly. In conclusion, peptide modification, through the introduction of additional membrane penetrating regions, can increase both the potency and activity spectra of natural template peptides, making them suitable candidates for new drug development
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