400 research outputs found

    Electron correlation in FeSe superconductor studied by bulk-sensitive photoemission spectroscopy

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    We have investigated the electronic structures of recently discovered superconductor FeSe by soft-x-ray and hard-x-ray photoemission spectroscopy with high bulk sensitivity. The large Fe 3d spectral weight is located in the vicinity of the Fermi level (EF), which is demonstrated to be a coherent quasi-particle peak. Compared with the results of the band structure calculation with local-density approximation, Fe 3d band narrowing and the energy shift of the band toward EF are found, suggesting an importance of the electron correlation effect in FeSe. The self energy correction provides the larger mass enhancement value (Z^-1=3.6) than in Fe-As superconductors and enables us to separate a incoherent part from the spectrum. These features are quite consistent with the results of recent dynamical mean-field calculations, in which the incoherent part is attributed to the lower Hubbard band.Comment: 8 pages, 5 figures, 1 talbl

    Multifrequency radar observations of marine clouds during the EPCAPE campaign

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    The Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE) was a year-round campaign conducted by the US Department of Energy at the Scripps Institution of Oceanography in La Jolla, CA, USA, with a focus on characterizing atmospheric processes at a coastal location. The ground-based prototype of a new Ka-, W-, and G-band (35.75, 94.88, and 238.8 GHz) profiling atmospheric radar, named CloudCube, which was developed at the Jet Propulsion Laboratory, took part in the experiment during 6 weeks in March and April 2023. This article describes the unique data sets that were obtained during the field campaign from a variety of marine clouds and light precipitation. These are, to the best of the authors' knowledge, the first observations of atmospheric clouds using simultaneous multifrequency measurements including 238.8 GHz. These data sets therefore provide an exceptional opportunity to study and analyze hydrometeors with diameters in the millimeter- and submillimeter size range that can be used to better understand cloud and precipitation structure, formation, and evolution. The data sets referenced in this article are intended to provide a complete, extensive, and high-quality collection of G-band data in the form of Doppler spectra and Doppler moments. In addition, Ka-band and W-band reflectivity and Ka-, W-, and G-band reflectivity ratio profiles are included for several cases of interest on 6 different days. The data sets can be found at https://doi.org/10.5281/zenodo.10076227 (Socuellamos et al., 2024).</p

    Shonan Rotation Averaging: Global Optimality by Surfing SO(p)nSO(p)^n

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    Shonan Rotation Averaging is a fast, simple, and elegant rotation averaging algorithm that is guaranteed to recover globally optimal solutions under mild assumptions on the measurement noise. Our method employs semidefinite relaxation in order to recover provably globally optimal solutions of the rotation averaging problem. In contrast to prior work, we show how to solve large-scale instances of these relaxations using manifold minimization on (only slightly) higher-dimensional rotation manifolds, re-using existing high-performance (but local) structure-from-motion pipelines. Our method thus preserves the speed and scalability of current SFM methods, while recovering globally optimal solutions.Comment: 30 pages (paper + supplementary material). To appear at the European Conference on Computer Vision (ECCV) 202

    Phthalocyanine-nanocarbon ensembles: From discrete molecular and supramolecular systems to hybrid nanomaterials

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Accounts of Chemical Research, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/ar5004384Conspectus Phthalocyanines (Pcs) are macrocyclic and aromatic compounds that present unique electronic features such as high molar absorption coefficients, rich redox chemistry, and photoinduced energy/electron transfer abilities that can be modulated as a function of the electronic character of their counterparts in donor-acceptor (D-A) ensembles. In this context, carbon nanostructures such as fullerenes, carbon nanotubes (CNTs), and, more recently, graphene are among the most suitable Pc companions. Pc-C60 ensembles have been for a long time the main actors in this field, due to the commercial availability of C60 and the ell-established synthetic methods for its functionalization. As a result, many Pc-C60 architectures have been prepared, featuring different connectivities (covalent or supramolecular), intermolecular interactions (self-organized or molecularly dispersed species), and Pc HOMO/LUMO levels. All these elements provide a versatile toolbox for tuning the photophysical properties in terms of the type of process (photoinduced energy/electron transfer), the nature of the interactions beteen the electroactive units (through bond or space), and the kinetics of the formation/decay of the photogenerated species. Some recent trends in this field include the preparation of stimuli-responsive multicomponent systems ith tunable photophysical properties and highly ordered nanoarchitectures and surface-supported systems shoing high charge mobilities. A breakthrough in the Pc-nanocarbon field as the appearance of CNTs and graphene, hich opened a ne avenue for the preparation of intriguing photoresponsive hybrid ensembles shoing light-stimulated charge separation. The scarce solubility of these 1-D and 2-D nanocarbons, together ith their loer reactivity ith respect to C60 stemming from their less strained sp2 carbon netorks, has not meant an unsurmountable limitation for the preparation of variety of Pc-based hybrids. These systems, hich sho improved solubility and dispersibility features, bring together the unique electronic transport properties of CNTs and graphene ith the excellent light-harvesting and tunable redox properties of Pcs. A singular and distinctive feature of these Pc-CNT/graphene (single- or fe-layers) hybrid materials is the control of the direction of the photoinduced charge transfer as a result of the band-like electronic structure of these carbon nanoforms and the adjustable electronic levels of Pcs. Moreover, these conjugates present intensified light-harvesting capabilities resulting from the grafting of several chromophores on the same nanocarbon platform.In this Account, recent progress in the construction of covalent and supramolecular Pc-nanocarbon ensembles is summarized, ith a particular emphasis on their photoinduced behavior. e believe that the high degree of control achieved in the preparation of Pc-carbon nanostructures, together ith the increasing knoledge of the factors governing their photophysics, ill allo for the design of next-generation light-fueled electroactive systems. Possible implementation of these Pc-nanocarbons in high performance devices is envisioned, finally turning into reality much of the expectations generated by these materialsFinancial support from the Spanish MICINN (CTQ2011-24187/BQU), the Comunidad de Madrid (S2013/MIT-2841 FOTOCARBON) and the EU (“SO2S” FP7-PEOPLE-2012-ITN, no.: 316975) is acknowledge

    Multiple structure alignment and consensus identification for proteins

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    <p>Abstract</p> <p>Background</p> <p>An algorithm is presented to compute a multiple structure alignment for a set of proteins and to generate a consensus (pseudo) protein which captures common substructures present in the given proteins. The algorithm represents each protein as a sequence of triples of coordinates of the alpha-carbon atoms along the backbone. It then computes iteratively a sequence of transformation matrices (i.e., translations and rotations) to align the proteins in space and generate the consensus. The algorithm is a heuristic in that it computes an approximation to the optimal alignment that minimizes the sum of the pairwise distances between the consensus and the transformed proteins.</p> <p>Results</p> <p>Experimental results show that the algorithm converges quite rapidly and generates consensus structures that are visually similar to the input proteins. A comparison with other coordinate-based alignment algorithms (MAMMOTH and MATT) shows that the proposed algorithm is competitive in terms of speed and the sizes of the conserved regions discovered in an extensive benchmark dataset derived from the HOMSTRAD and SABmark databases.</p> <p>The algorithm has been implemented in C++ and can be downloaded from the project's web page. Alternatively, the algorithm can be used via a web server which makes it possible to align protein structures by uploading files from local disk or by downloading protein data from the RCSB Protein Data Bank.</p> <p>Conclusions</p> <p>An algorithm is presented to compute a multiple structure alignment for a set of proteins, together with their consensus structure. Experimental results show its effectiveness in terms of the quality of the alignment and computational cost.</p

    An Analysis of Errors in Graph-Based Keypoint Matching and Proposed Solutions

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    International audienceAn error occurs in graph-based keypoint matching when key-points in two different images are matched by an algorithm but do not correspond to the same physical point. Most previous methods acquire keypoints in a black-box manner, and focus on developing better algorithms to match the provided points. However to study the complete performance of a matching system one has to study errors through the whole matching pipeline, from keypoint detection, candidate selection to graph optimisation. We show that in the full pipeline there are six different types of errors that cause mismatches. We then present a matching framework designed to reduce these errors. We achieve this by adapting keypoint detectors to better suit the needs of graph-based matching, and achieve better graph constraints by exploiting more information from their keypoints. Our framework is applicable in general images and can handle clutter and motion discontinuities. We also propose a method to identify many mismatches a posteriori based on Left-Right Consistency inspired by stereo matching due to the asymmetric way we detect keypoints and define the graph

    Identification and functional characterisation of CRK12:CYC9, a novel cyclin-dependent kinase (CDK)-cyclin complex in Trypanosoma brucei

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    The protozoan parasite, Trypanosoma brucei, is spread by the tsetse fly and causes trypanosomiasis in humans and animals. Both the life cycle and cell cycle of the parasite are complex. Trypanosomes have eleven cdc2-related kinases (CRKs) and ten cyclins, an unusually large number for a single celled organism. To date, relatively little is known about the function of many of the CRKs and cyclins, and only CRK3 has previously been shown to be cyclin-dependent in vivo. Here we report the identification of a previously uncharacterised CRK:cyclin complex between CRK12 and the putative transcriptional cyclin, CYC9. CRK12:CYC9 interact to form an active protein kinase complex in procyclic and bloodstream T. brucei. Both CRK12 and CYC9 are essential for the proliferation of bloodstream trypanosomes in vitro, and we show that CRK12 is also essential for survival of T. brucei in a mouse model, providing genetic validation of CRK12:CYC9 as a novel drug target for trypanosomiasis. Further, functional characterisation of CRK12 and CYC9 using RNA interference reveals roles for these proteins in endocytosis and cytokinesis, respectively

    Association of C-reactive protein with efficacy of avelumab plus axitinib in advanced renal cell carcinoma: long-term follow-up results from JAVELIN Renal 101

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    BACKGROUND: C-reactive protein (CRP) is an important prognostic and predictive factor in advanced renal cell carcinoma (aRCC). We report the association of CRP levels at baseline and early after treatment with efficacy of avelumab plus axitinib or sunitinib from the phase III JAVELIN Renal 101 trial. PATIENTS AND METHODS: Patients were categorized into normal (baseline CRP &lt;10 mg/l), normalized (baseline CRP ≥10 mg/l and ≥1 CRP value decreased to &lt;10 mg/l during 6-week treatment), and non-normalized (CRP ≥10 mg/l at baseline and during 6-week treatment) CRP groups. Progression-free survival and best overall response from the second interim analysis and overall survival (OS) from the third interim analysis were assessed. RESULTS: In the avelumab plus axitinib and sunitinib arms, respectively, 234, 51, and 108 patients and 232, 36, and 128 patients were categorized into normal, normalized, and non-normalized CRP groups. In respective CRP groups, objective response rates [95% confidence interval (CI)] were 56.0% (49.4% to 62.4%), 66.7% (52.1% to 79.2%), and 45.4% (35.8% to 55.2%) with avelumab plus axitinib and 30.6% (24.7% to 37.0%), 41.7% (25.5% to 59.2%), and 19.5% (13.1% to 27.5%) with sunitinib; complete response rates were 3.8%, 11.8%, and 0.9% and 3.0%, 0%, and 1.6%, respectively. Median progression-free survival (95% CI) was 15.2 months (12.5-21.0 months), not reached (NR) [11.1 months-not estimable (NE)], and 7.0 months (5.6-9.9 months) with avelumab plus axitinib and 11.2 months (8.4-13.9 months), 11.2 months (6.7-13.8 months), and 4.2 months (2.8-5.6 months) with sunitinib; median OS (95% CI) was NR (42.2 months-NE), NR (30.4 months-NE), and 23.0 months (18.4-33.1 months) and NR (39.0 months-NE), 39.8 months (21.7-NE), and 19.1 months (16.3-25.3 months), respectively. Multivariate analyses demonstrated that normalized or non-normalized CRP levels were independent factors for the prediction of objective response rate or OS, respectively, with avelumab plus axitinib. CONCLUSIONS: In patients with aRCC, CRP levels at baseline and early after treatment may predict efficacy with avelumab plus axitinib
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