1,108 research outputs found

    Towards Practical Plug-and-Play Diffusion Models

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    Diffusion-based generative models have achieved remarkable success in image generation. Their guidance formulation allows an external model to plug-and-play control the generation process for various tasks without fine-tuning the diffusion model. However, the direct use of publicly available off-the-shelf models for guidance fails due to their poor performance on noisy inputs. For that, the existing practice is to fine-tune the guidance models with labeled data corrupted with noises. In this paper, we argue that this practice has limitations in two aspects: (1) performing on inputs with extremely various noises is too hard for a single model; (2) collecting labeled datasets hinders scaling up for various tasks. To tackle the limitations, we propose a novel strategy that leverages multiple experts where each expert is specialized in a particular noise range and guides the reverse process at its corresponding timesteps. However, as it is infeasible to manage multiple networks and utilize labeled data, we present a practical guidance framework termed Practical Plug-And-Play (PPAP), which leverages parameter-efficient fine-tuning and data-free knowledge transfer. We exhaustively conduct ImageNet class conditional generation experiments to show that our method can successfully guide diffusion with small trainable parameters and no labeled data. Finally, we show that image classifiers, depth estimators, and semantic segmentation models can guide publicly available GLIDE through our framework in a plug-and-play manner

    Observation of the orbital Hall effect in a light metal Ti

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    The orbital angular momentum is a core ingredient of orbital magnetism, spin Hall effect, giant Rashba spin splitting, orbital Edelstein effect, and spin-orbit torque. However, its experimental detection is tricky. In particular, direct detection of the orbital Hall effect remains elusive despite its importance for electrical control of magnetic nanodevices. Here we report the direct observation of the orbital Hall effect in a light metal Ti. The Kerr rotation by the accumulated orbital magnetic moment is measured at Ti surfaces, whose result agrees with theoretical calculations semiquantitatively and is supported by the orbital torque measurement in Ti-based magnetic heterostructures. The results confirm the electron orbital angular momentum as an essential dynamic degree of freedom, which may provide a novel mechanism for the electric control of magnetism. The results may also deepen the understanding of spin, valley, phonon, and magnon dynamics coupled with orbital dynamics

    Analysis of Scientific Papers Included in the

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    Background The purpose of our study was to analyze scientific papers published by SouthKorean plastic surgeons in journals included in the Science Citation Index Expanded (SCIE),and to evaluate the publication and research activities of Korean plastic surgeon.Methods We conducted a survey of SCIE papers in the field of plastic surgery published bySouth Korean authors between 2001 and 2010 using Web of Science software. We furtheranalyzed these results according to the number of publications per year, journals, institution,and type of papers. We also compared the total number of citations to published scientificpapers. We analyzed the rank of South Korea among other countries in representative journals.Results Overall, 667 papers were published by South Korean authors between 2001 and 2010.The number of publications increased dramatically from 2003 (n=31) to 2010 (n=139).Subsequently, the ten most productive Korean medical colleges were identified. All publishedpapers received 2,311 citations and the citation to paper ratio was 3.49. The rank of Koreaamong other countries in terms of the number of published papers remained in the top 10during the recent 10 years.Conclusions Publication output of Korean plastic surgeon over the last 10 years showed aremarkable growth in terms of quantity and quality. Currently, Korea is among the top sixcountries in representative plastic surgery journals. Korean plastic surgeons have playeda central role in this progress, and it is anticipated that they will continue to do so in thefuture

    Analysis of Scientific Papers Included in the Sciences Citation Index Expanded Written by South Korean Plastic Surgeons: 2001-2010

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    BackgroundThe purpose of our study was to analyze scientific papers published by South Korean plastic surgeons in journals included in the Science Citation Index Expanded (SCIE), and to evaluate the publication and research activities of Korean plastic surgeon.MethodsWe conducted a survey of SCIE papers in the field of plastic surgery published by South Korean authors between 2001 and 2010 using Web of Science software. We further analyzed these results according to the number of publications per year, journals, institution, and type of papers. We also compared the total number of citations to published scientific papers. We analyzed the rank of South Korea among other countries in representative journals.ResultsOverall, 667 papers were published by South Korean authors between 2001 and 2010. The number of publications increased dramatically from 2003 (n=31) to 2010 (n=139). Subsequently, the ten most productive Korean medical colleges were identified. All published papers received 2,311 citations and the citation to paper ratio was 3.49. The rank of Korea among other countries in terms of the number of published papers remained in the top 10 during the recent 10 years.ConclusionsPublication output of Korean plastic surgeon over the last 10 years showed a remarkable growth in terms of quantity and quality. Currently, Korea is among the top six countries in representative plastic surgery journals. Korean plastic surgeons have played a central role in this progress, and it is anticipated that they will continue to do so in the future

    Dichotomous role of Shp2 for naïve and primed pluripotency maintenance in embryonic stem cells

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    Background : The requirement of the Mek1 inhibitor (iMek1) during naïve pluripotency maintenance results from the activation of the Mek1-Erk1/2 (Mek/Erk) signaling pathway upon leukemia inhibitory factor (LIF) stimulation. Methods : Through a meta-analysis of previous genome-wide screening for negative regulators of naïve pluripotency, Ptpn11 (encoding the Shp2 protein, which serves both as a tyrosine phosphatase and putative adapter), was predicted as one of the key factors for the negative modulation of naïve pluripotency through LIF-dependent Jak/Stat3 signaling. Using an isogenic pair of naïve and primed mouse embryonic stem cells (mESCs), we demonstrated the differential role of Shp2 in naïve and primed pluripotency. Results : Loss of Shp2 increased naïve pluripotency by promoting Jak/Stat3 signaling and disturbed in vivo differentiation potential. In sharp contrast, Shp2 depletion significantly impeded the self-renewal of ESCs under primed culture conditions, which was concurrent with a reduction in Mek/Erk signaling. Similarly, upon treatment with an allosteric Shp2 inhibitor (iShp2), the cells sustained Stat3 phosphorylation and decoupled Mek/Erk signaling, thus iShp2 can replace the use of iMek1 for maintenance of naïve ESCs. Conclusions : Taken together, our findings highlight the differential roles of Shp2 in naïve and primed pluripotency and propose the usage of iShp2 instead of iMek1 for the efficient maintenance and establishment of naïve pluripotency.This work was supported by a grant from the National Research Foundation of Korea (NRF-2020R1A2C2005914). This work was also supported by the Creative-Pioneering Researchers Program through Seoul National University (SNU)

    Outer Membrane Vesicles Derived From Escherichia coli Regulate Neutrophil Migration by Induction of Endothelial IL-8

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    Outer membrane vesicles (OMVs) are spherical, proteolipid nanostructures that are constitutively released by Gram-negative bacteria including Escherichia coli. Although it has been shown that administration of E. coli OMVs stimulates a strong pulmonary inflammatory response with infiltration of neutrophils into the lungs in vivo, the mechanism of E. coli OMV-mediated neutrophil recruitment is poorly characterized. In this study, we observed significant infiltration of neutrophils into the mouse lung tissues in vivo, with increased expression of the neutrophil chemoattractant CXCL1, a murine functional homolog of human IL-8, on intraperitoneal administration of E. coli OMVs. In addition, OMVs and CD31-positive endothelial cells colocalized in the mouse lungs. Moreover, in vitro results showed that E. coli OMVs significantly increased IL-8 release from human microvascular endothelial cells and toll-like receptor (TLR)4 was found to be the main component for recognizing E. coli OMVs among human endothelial cell-associated TLRs. Furthermore, the transmigration of neutrophils was suppressed in the lung tissues obtained from TLR4 knockout mice treated with E. coli OMVs. Taken together, our data demonstrated that E. coli OMVs potently recruit neutrophils into the lung via the release of IL-8/CXCL1 from endothelial cells in TLR4- and NF-κB-dependent manners

    Low-temperature formation of epitaxial graphene on 6H-SiC induced by continuous electron beam irradiation

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    It is observed that epitaxial graphene forms on the surface of a 6H-SiC substrate by irradiating electron beam directly on the sample surface in high vacuum at relatively low temperature (similar to 670 degrees C). The symmetric shape and full width at half maximum of 2D peak in the Raman spectra indicate that the formed epitaxial graphene is turbostratic. The gradual change of the Raman spectra with electron beam irradiation time increasing suggests that randomly distributed small grains of epitaxial graphene form first and grow laterally to cover the entire irradiated area. The sheet resistance of epitaxial graphene film is measured to be similar to 6.7 k Omega/sq.open4

    The genome sequence of Xanthomonas oryzae pathovar oryzae KACC10331, the bacterial blight pathogen of rice

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    The nucleotide sequence was determined for the genome of Xanthomonas oryzae pathovar oryzae (Xoo) KACC10331, a bacterium that causes bacterial blight in rice (Oryza sativa L.). The genome is comprised of a single, 4 941 439 bp, circular chromosome that is G + C rich (63.7%). The genome includes 4637 open reading frames (ORFs) of which 3340 (72.0%) could be assigned putative function. Orthologs for 80% of the predicted Xoo genes were found in the previously reported X.axonopodis pv. citri (Xac) and X.campestris pv. campestris (Xcc) genomes, but 245 genes apparently specific to Xoo were identified. Xoo genes likely to be associated with pathogenesis include eight with similarity to Xanthomonas avirulence (avr) genes, a set of hypersensitive reaction and pathogenicity (hrp) genes, genes for exopolysaccharide production, and genes encoding extracellular plant cell wall-degrading enzymes. The presence of these genes provides insights into the interactions of this pathogen with its gramineous host

    Ginsenoside F1 Promotes Cytotoxic Activity of NK Cells via Insulin-Like Growth Factor-1-Dependent Mechanism

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    Ginsenosides are the principal active components of ginseng and are considered attractive candidates for combination cancer therapy because they can kill tumors and have favorable safety profiles. However, the overall benefit of ginsenosides remains unclear, particularly in cancer immunosurveillance, considering the controversial results showing repression or promotion of immune responses. Here we identify a potentiating role of ginsenoside F1 (G-F1) in cancer surveillance by natural killer (NK) cells. Among 15 different ginsenosides, G-F1 most potently enhanced NK cell cytotoxicity in response to diverse activating receptors and cancer cells. G-F1 also improved cancer surveillance in mouse models of lymphoma clearance and metastatic melanoma that rely on NK cell activity. G-F1-treated NK cells exhibited elevated cytotoxic potential such as upregulation of cytotoxic mediators and of activation signals upon stimulation. NK cell potentiation by G-F1 was antagonized by insulin-like growth factor (IGF)-1 blockade and recapitulated by IGF-1 treatment, suggesting the involvement of IGF-1. Thus, our results suggest that G-F1 enhances NK cell function and may have chemotherapeutic potential in NK cell-based immunotherapy. We anticipate our results to be a starting point for further comprehensive studies of ginsenosides in the immune cells mediating cancer surveillance and the development of putative therapeutics

    Structure-Activity Relationship Analysis of YM155 for Inducing Selective Cell Death of Human Pluripotent Stem Cells

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    Despite great potential for regenerative medicine, the high tumorigenic potential of human pluripotent stem cells (hPSCs) to form undesirable teratoma is an important technical hurdle preventing safe cell therapy. Various small molecules that induce the complete elimination of undifferentiated hPSCs, referred to as “stemotoxics,” have been developed to facilitate tumor-free cell therapy, including the Survivin inhibitor YM155. In the present work, based on the chemical structure of YM155, total 26 analogs were synthesized and tested for stemotoxic activity toward human embryonic stem cells (hESCs) and induced PSCs (iPSCs). We found that a hydrogen bond acceptor in the pyrazine ring of YM155 derivatives is critical for stemotoxic activity, which is completely lost in hESCs lacking SLC35F2, which encodes a solute carrier protein. These results suggest that hydrogen bonding interactions between the nitrogens of the pyrazine ring and the SLC35F2 protein are critical for entry of YM155 into hPSCs, and hence stemotoxic activity
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