2,052 research outputs found
Oxygen-Vacancy-Induced Orbital Reconstruction of Ti Ions at the Interface of LaAlO3/SrTiO3 Heterostructures: A Resonant Soft-X-Ray Scattering Study
Resonant soft-x-ray scattering measurements have been performed to investigate interface electronic structures of (LaAlO3/SrTiO3) superlattices. Resonant scattering intensities at superlattice reflections show clear evidence of degeneracy lifting in t(2g) states of interface Ti ions. Polarization dependence of intensities indicates the energy of d(xy) states is lower by similar to 1 eV than two other t(2g) states. The energy splitting is insensitive to epitaxial strain. The orbital reconstruction is induced by oxygen vacancies and confined to the interface within two unit cells, indicating charge compensation at the polar interfaces. DOI: 10.1103/PhysRevLett.110.017401X112723Nsciescopu
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REDSHIFT MEASUREMENT and SPECTRAL CLASSIFICATION for eBOSS GALAXIES with the REDMONSTER SOFTWARE
We describe the redmonster automated redshift measurement and spectral classification software designed for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV). We describe the algorithms, the template standard and requirements, and the newly developed galaxy templates to be used on eBOSS spectra. We present results from testing on early data from eBOSS, where we have found a 90.5% automated redshift and spectral classification success rate for the luminous red galaxy sample (redshifts 0.6 ≲ z ≲ 1.0). The redmonster performance meets the eBOSS cosmology requirements for redshift classification and catastrophic failures and represents a significant improvement over the previous pipeline. We describe the empirical processes used to determine the optimum number of additive polynomial terms in our models and an acceptable δX2rthreshold for declaring statistical confidence. Statistical errors on redshift measurement due to photon shot noise are assessed, and we find typical values of a few tens of km s-1. An investigation of redshift differences in repeat observations scaled by error estimates yields a distribution with a Gaussian mean and standard deviation of μ ∼ 0.01 and σ ∼ 0.65, respectively, suggesting the reported statistical redshift uncertainties are over-estimated by ∼54%. We assess the effects of object magnitude, signal-to-noise ratio, fiber number, and fiber head location on the pipeline's redshift success rate. Finally, we describe directions of ongoing development
Coalescent-based genome analyses resolve the early branches of the euarchontoglires
Despite numerous large-scale phylogenomic studies, certain parts of the mammalian tree are extraordinarily difficult to resolve. We used the coding regions from 19 completely sequenced genomes to study the relationships within the super-clade Euarchontoglires (Primates, Rodentia, Lagomorpha, Dermoptera and Scandentia) because the placement of Scandentia within this clade is controversial. The difficulty in resolving this issue is due to the short time spans between the early divergences of Euarchontoglires, which may cause incongruent gene trees. The conflict in the data can be depicted by network analyses and the contentious relationships are best reconstructed by coalescent-based analyses. This method is expected to be superior to analyses of concatenated data in reconstructing a species tree from numerous gene trees. The total concatenated dataset used to study the relationships in this group comprises 5,875 protein-coding genes (9,799,170 nucleotides) from all orders except Dermoptera (flying lemurs). Reconstruction of the species tree from 1,006 gene trees using coalescent models placed Scandentia as sister group to the primates, which is in agreement with maximum likelihood analyses of concatenated nucleotide sequence data. Additionally, both analytical approaches favoured the Tarsier to be sister taxon to Anthropoidea, thus belonging to the Haplorrhine clade. When divergence times are short such as in radiations over periods of a few million years, even genome scale analyses struggle to resolve phylogenetic relationships. On these short branches processes such as incomplete lineage sorting and possibly hybridization occur and make it preferable to base phylogenomic analyses on coalescent methods
Bim Nuclear Translocation and Inactivation by Viral Interferon Regulatory Factor
Viral replication efficiency is in large part governed by the ability of viruses to counteract pro-apoptotic signals induced by infection of the host cell. Human herpesvirus 8 (HHV-8) uses several strategies to block the host's innate antiviral defenses via interference with interferon and apoptotic signaling. Contributors include the four viral interferon regulatory factors (vIRFs 1–4), which function in dominant negative fashion to block cellular IRF activities in addition to targeting IRF signaling-induced proteins such as p53 and inhibiting other inducers of apoptosis such as TGFβ receptor-activated Smad transcription factors. Here we identify direct targeting by vIRF-1 of BH3-only pro-apoptotic Bcl-2 family member Bim, a key negative regulator of HHV-8 replication, to effect its inactivation via nuclear translocation. vIRF-1-mediated relocalization of Bim was identified in transfected cells, by both immunofluorescence assay and western analysis of fractionated cell extracts. Also, co-localization of vIRF-1 and Bim was detected in nuclei of lytically infected endothelial cells. In vitro co-precipitation assays using purified vIRF-1 and Bim revealed direct interaction between the proteins, and Bim-binding residues of vIRF-1 were mapped by deletion and point mutagenesis. Generation and experimental utilization of Bim-refractory vIRF-1 variants revealed the importance of vIRF-1:Bim interaction, specifically, in pro-replication and anti-apoptotic activity of vIRF-1. Furthermore, blocking of the interaction with cell-permeable peptide corresponding to the Bim-binding region of vIRF-1 confirmed the relevance of vIRF-1:Bim association to vIRF-1 pro-replication activity. To our knowledge, this is the first report of an IRF protein that interacts with a Bcl-2 family member and of nuclear sequestration of Bim or any other member of the family as a means of inactivation. The data presented reveal a novel mechanism utilized by a virus to control replication-induced apoptosis and suggest that inhibitory targeting of vIRF-1:Bim interaction may provide an effective antiviral strategy
Apolipophorin-III Mediates Antiplasmodial Epithelial Responses in Anopheles gambiae (G3) Mosquitoes
Apolipophorin-III (ApoLp-III) is known to play an important role in lipid transport and innate immunity in lepidopteran insects. However, there is no evidence of involvement of ApoLp-IIIs in the immune responses of dipteran insects such as Drosophila and mosquitoes.We report the molecular and functional characterization of An. gambiae apolipophorin-III (AgApoLp-III). Mosquito ApoLp-IIIs have diverged extensively from those of lepidopteran insects; however, the predicted tertiary structure of AgApoLp-III is similar to that of Manduca sexta (tobacco hornworm). We found that AgApoLp-III mRNA expression is strongly induced in the midgut of An. gambiae (G3 strain) mosquitoes in response to Plasmodium berghei infection. Furthermore, immunofluorescence stainings revealed that high levels of AgApoLp-III protein accumulate in the cytoplasm of Plasmodium-invaded cells and AgApoLp-III silencing increases the intensity of P. berghei infection by five fold.There are broad differences in the midgut epithelial responses to Plasmodium invasion between An. gambiae strains. In the G3 strain of An. gambiae AgApoLp-III participates in midgut epithelial defense responses that limit Plasmodium infection
Atherosclerosis in young Brazilians suffering violent deaths: a pathological study
<p>Abstract</p> <p>Background</p> <p>Atherosclerosis is the leading cause of coronary heart disease and ischemic stroke, which can cause sudden death in adulthood. In general, the clinical manifestations of cardiovascular diseases are caused by atherosclerosis, which is a process that starts during middle age. More recent studies indicate that the atherosclerotic process begins during childhood.</p> <p>Methods</p> <p>To evaluate the extent of atherosclerotic disease in young Brazilians, we conducted a study of the pathological alterations in the major arteries of victims of violent death. Samples of the right carotid artery, left coronary artery, and thoracic aorta of young victims of violent death were analyzed and graded in accordance with the histological atherosclerotic lesion types proposed by the American Heart Association. Samples were collected from 100 individuals who had died from external causes, aged from 12 to 33 years.</p> <p>Results</p> <p>The majority of cases (83%) were male, and 66% of deaths were homicides caused by firearms. The median age was 20.0 years and mean body mass index was 20.9 kg/m<sup>2</sup>. Of the right carotid artery specimens, 3% were normal, 55% had type I, 40% had type II, 1% had type III, and 1% had type IV atherosclerotic lesions. Of the left coronary artery specimens, 5% were normal, 48% had type I, 41% had type II, 3% had type III, and 3% had type IV lesions. Of the thoracic aorta specimens, none were normal, 13% had type I, 64% had type II, 22% had type III, and 1% had type IV lesions. Overall, 97.34% of arteries examined had some degree of atherosclerosis. The most common histological type was type II (foam cells). No thoracic aorta specimens were normal, and the coronary artery specimens had the most atherosclerosis.</p> <p>Conclusions</p> <p>Our results show a high prevalence of atherosclerotic lesions among young people in Brazil. Intervention should be undertaken to decrease the rate of sudden cardiac death in the adult population.</p
A peptide derived from TIMP-3 inhibits multiple angiogenic growth factor receptors and tumour growth and inflammatory arthritis in mice
The binding of vascular endothelial growth factor (VEGF) to VEGF receptor-2 (VEGFR-2) on the surface of vascular endothelial cells stimulates many steps in the angiogenic pathway. Inhibition of this interaction is proving of value in moderating the neovascularization accompanying age-related macular degeneration and in the treatment of cancer. Tissue inhibitor of metalloproteinases-3 (TIMP-3) has been shown to be a natural VEGFR-2 specific antagonist—an activity that is independent of its ability to inhibit metalloproteinases. In this investigation we localize this activity to the C-terminal domain of the TIMP-3 molecule and characterize a short peptide, corresponding to part of this domain, that not only inhibits all three VEGF-family receptors, but also fibroblast growth factor and platelet-derived growth factor receptors. This multiple-receptor inhibition may explain why the peptide was also seen to be a powerful inhibitor of tumour growth and also a partial inhibitor of arthritic joint inflammation in vivo
New structural insights into the role of TROVE2 complexes in the on-set and pathogenesis of systemic lupus eythematosus determined by a combiantion of QCM-D and DPI
The final publication is available at link.springer.com.[EN] The mechanism of self-recognition of the autoantigen TROVE2, a common biomarker in autoimmune diseases, has been studied with a quartz crystal microbalance with dissipation monitoring (QCM-D) and dual polarization interferometry (DPI). The complementarity and remarkable analytical features of both techniques has allowed new insights into the onset of systemic lupus erythematosus (SLE) to be achieved at the molecular level. The in vitro study for SLE patients and healthy subjects suggests that anti-TROVE2 autoantibodies may undergo an antibody bipolar bridging. An epitope-paratope-specific binding initially occurs to activate a hidden Fc receptor in the TROVE2 tertiary structure. This bipolar mechanism may contribute to the pathogenic accumulation of anti-TROVE2 autoantibody immune complex in autoimmune disease. Furthermore, the specific calcium-dependent protein-protein bridges point out at how the TRIM21/TROVE2 association might occur, suggesting that the TROVE2 protein could stimulate the intracellular immune signaling via the TRIM21 PRY-SPRY domain. These findings may help to better understand the origins of the specificity and affinity of TROVE2 interactions, which might play a key role in the SLE pathogenesis. This manuscript gives one of the first practical applications of two novel functions (-df/dD and Delta h/molec) for the analysis of the data provided by QCM-D and DPI. In addition, it is the first time that QCM-D has been used for mapping hidden Fc receptors as well as linear epitopes in a protein tertiary structure.We would like to thank Sylvia Daunert for her invaluable help with the discussion of the paper. Furthermore, we acknowledge financial support from the Generalitat Valenciana (GVA-PROMETEOII/2014/040) as well as the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under award numbers CTQ2013-45875-R and CTQ2013-42914-RJuste-Dolz, AM.; Do Nascimento, NM.; Monzó, IS.; Grau-García, E.; Roman-Ivorra, JA.; López-Paz, JL.; Escorihuela Fuentes, J.... (2019). New structural insights into the role of TROVE2 complexes in the on-set and pathogenesis of systemic lupus eythematosus determined by a combiantion of QCM-D and DPI. Analytical and Bioanalytical Chemistry. 411(19):4709-4720. https://doi.org/10.1007/s00216-018-1407-xS4709472041119Kakatia S, Teronpia R, Barmanb B. Frequency, pattern and determinants of flare in systemic lupus erythematosus: a study from North East India. Egypt Rheumatol. 2015;37:S55–9.Kuhn A, Wenzel J, Weyd H. Photosensitivity, apoptosis, and cytokines in the pathogenesis of lupus erythematosus: a critical review. 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Analytical model for the calculation of lateral velocity distributions in potential cross-sections
[EN] The hydraulic modeling of water depth and flow velocities in open channel flows that were fitted by power-law cross-section stand out for their versatility, allowing their use in numerous practical applications, both in natural and artificial channels. The determination of the hydraulic variables of depth and average velocity has been widely studied in potential cross-sections; however, the variation seen in these variables along the cross-section was not found in the literature. Knowledge of this variation allows the development of studies (e.g. to know the approximate damage in different areas of the cross-section, to analyse sediment transport, or other applications in river hydraulics). This paper presents a methodology which allows calculation of the hydraulic variables in any area of a power-law cross-section. The methodology is applied to symmetrical cross-sections, comparing its generated results with the obtained values by different computational hydraulic codes, which are thoroughly accepted by scientific community, such as CES, HEC-RAS and IBER. The obtained predictions of hydraulic parameters (using the explicit formulation described in this research) present very low errors when compared with results of other models, with great computational cost. These errors reach a root mean square error (RMSE) of 0.13 and 0.05 in the determination of velocities' lateral distribution and the ratio between velocity and average velocity. These values indicate a very successful validation for the analysed symmetrical sections.[ES] La modelización hidráulica de calados y velocidades de flujo, en cauces con secciones que admiten
una representación de tipo potencial, se destaca por su versatilidad, permitiendo su utilización en
numerosas aplicaciones prácticas tanto en canales naturales como artificiales. El cálculo de las
variables hidráulicas (calado y velocidad media) ha sido ampliamente estudiado para este tipo de
secciones. Sin embargo, en la literatura técnica no se han encontrado estudios que muestren la
variación de estas magnitudes a lo largo de la sección transversal. El conocimiento de esta variación
permite desarrollar estudios (ejemplo: conocer de manera aproximada los daños en diferentes zonas
de la sección, analizar el transporte de sedimentos, estudiar los procesos de erosión u otras aplicaciones en hidráulica fluvial). Presentamos una metodología que permite el cálculo de las variables
hidráulicas en cualquier zona de una sección tipo potencial. La metodología es aplicada a secciones
simétricas, comparando los resultados generados con los obtenidos por diferentes códigos
hidráulicos computacionales ampliamente aceptados por la comunidad científica (p-e- CES, HECRAS e IBER). Las predicciones de los parámetros hidráulicos obtenidas (usando la formulación
explícita descrita en este artículo) presentan errores muy bajos, en comparación con otros modelos
con mayor costo computacional. Estos errores alcanzan un valor promedio para la raíz del error
cuadrático medio (RMSE) en el cálculo de la distribución lateral de velocidades de 0.13 y de 0.05, en el
cálculo de la relación de velocidades respecto a la velocidad media. Estos valores indican una
validación muy satisfactoria para las secciones simétricas analizadas.Sánchez-Romero, F.; Pérez-Sánchez, M.; López Jiménez, PA. (2018). Modelo analítico para el cálculo de distribuciones de velocidad laterales en secciones tipo potencial-ley. RIBAGUA - Revista Iberoamericana del Agua. 5(1):29-47. doi:10.1080/23863781.2018.1442189S29475
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