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Rheological and tribological approaches as a tool for the development of sustainable lubricating greases based on nano-montmorillonite and castor oil

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Friction 2021年第2期9卷 415-428页

作者： Jose Enrique marTÍN-ALFONSO mar.a Jose marTÍN-ALFONSO Concepción VALENCIA mar.a Teresa CUBERES Department of Chemical Engineering and Materials Science Campus de“El Carmen”University of HuelvaChemical Product and Process Technology Research Center(Pro2TecS)Huelva 21071Spain Department of Applied Mechanics and Project Engineering University of Castilla-La ManchaAlmadén 13400Spain

This study investigates the development of novel montmorillonite/castor oil blends to formulate sustainable lubricating greases to promote the replacement of petrochemicals industry-derived materials by substances obtained from renewable ***,the effect of the thickener concentration on the rheological,chemical,thermal,tribological properties,and atomic force microscopy(AFM)microstructure of these systems were *** results showed that the C20A nanoclay content could be used to modulate the viscosity values,the linear viscoelastic functions,and tribological properties of these montmorillonite *** general,these gel-like dispersions exhibited remar.able lubricant properties;the samples showed values of the friction coefficient and wear scars similar or lower than those obtained with model bentonite grease.

关键词： lubricating greases nanoclay vegetable oil rheology tribology

Existence and Uniqueness to a Fully Nonlinear Version of the Loewner–Nirenberg Problem Dedicated to Celebrate the Sixtieth Anniversary of USTC

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Communications in Mathematics and Statistics 2018年第3期6卷 269-288页

作者： mar.a del mar González YanYan Li Luc Nguyen Departamento de Matemáticas Universidad Autónoma de MadridCampus de Cantoblanco28049 MadridSpain Department of Mathematics Hill CenterBusch CampusRutgers University110 Frelinghuysen RoadPiscatawayNJ 08854USA Mathematical Institute and St Edmund Hall University of OxfordAndrew Wiles BuildingRadcliffe Observatory QuarterWoodstock RoadOxford OX26GGUK

We consider the problem of finding on a given Euclidean domainof dimension n≥3 a complete conformally flat metric whose Schouten curvature A satisfies some equations of the form f(λ(−A))=*** generalizes a problem considered by Loewner and Nirenberg for the scalar *** prove the existence and uniqueness of such metric when the boundary δΩ is a smooth bounded hypersurface(of codimension one).When δΩ contains a compact smooth submanifold ∑ of higher codimension with δΩ\∑ being compact,we also give a‘sharp’condition for the divergence to infinity of the conformal factor near ∑ in terms of the codimension.

关键词： Fully nonlinear Loewner-Nirenberg problem Singular fully nonlinear Yamabe metrics Conformal invariance

Brain and spinal cord trauma:what we know about the therapeutic potential of insulin growth factor 1 gene therapy

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Neural Regeneration Research 2023年第2期18卷 253-257页

作者： mar.a Jose Bellini Florencia Labombarda Lab de Bioquímica del Envejecimiento INIBIOLP-CONICETFacultad de Ciencias MedicinaUniversidad Nacional de La PlataLa PlataArgentina Laboratory of Neuroendocrine Biochemistry IBYME-CONICETBuenos AiresArgentina Department of Human Biochemistry Faculty of MedicineUniversidad de Buenos AiresBuenos AiresArgentina

Although little attention has been paid to cognitive and emotional dysfunctions observed in patients after spinal co rd injury,several reports have described impairments in cognitive *** group also has contributed significantly to the study of cognitive impairments in a rat model of spinal co rd *** findings are very significant because they demonstrate that cognitive and mood deficits are not induced by lifestyle changes,drugs of abuse,and combined *** are related to changes in brain structures involved in cognition and emotion,such as the *** spinal cord injury decreases neurogenesis,enhances glial reactivity leading to hippocampal neuroinflammation,and trigge rs cognitive *** brain distal abnormalities are recently called te rtiary *** that there is no treatment for Tertiary Damage,insulin growth factor 1 gene therapy emerges as a good *** growth factor 1 gene thera py recove rs neurogenesis and induces the polarization from pro-inflammato ry towards anti-inflammatory microglial phenotypes,which represents a potential strategy to treat the neuroinflammation that supports te rtiary *** growth factor 1 gene therapy can be extended to other central nervous system pathologies such as traumatic brain injury where the neuroinflammatory component is *** growth factor 1 gene therapy could emerge as a new therapeutic strategy for treating traumatic brain injury and spinal cord injury.

关键词： cognitive impairments gene therapy hippocampus insulin growth factor 1 microglial cells neurodegeneration neurogenesis neuroinflammation spinal cord injury traumatic brain injury

Weighted Inequalities for Fractional Type Operators with Some Homogeneous Kernels

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Acta Mathematica Sinica,English Series 2013年第3期29卷 449-460页

作者： mar.a Silvina RIVEROS mar.a URCIUOLO FaMAF-UNC CIEM-CONICET Ciudad Universitaria

In this paper, we study integral operators of the formappropriate weighted BMO and weak type estimates for certain weights satisfying the above inequality. We also give a Coifman type estimate for these operators.

关键词： Fractional operators Calderon-Zygmund operators BMO Muckenhoupt weights

Human Long Telomeres and Epigenetic marks

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CellBio 2013年第2期2卷 70-72页

作者： mar.a I. Vaquero-Sedas Miguel A. vega-Palas Instituto de Bioquímica Vegetal y Fotosíntesis Universidad de Sevilla-CSIC Seville Spain

We have read with interest the article “Telomere length regulates TERRA levels through increased trimethylation of telomeric H3K9 and HP1α” by Arnoult and colleagues [1]. This study focuses on human telomeric chromatin structure using different techniques like Chromatin Immunoprecipitation (ChIP), cytolocalization or RT-qPCR. However, it has been performed without taking into consideration the presence of Interstitial Telomeric Sequences (ITSs) in the human genome. Some of the conclusions of the article are undoubtedly clear but there are others that might be explained in alternative ways, considering the existence of ITSs. Following, we mention some comments that arise from this interesting article.

关键词： Telomeres TERRA Epigenetics Human

The restriction endonuclease Tru9I is a useful tool to analyze telomere sequences separately from interstitial telomeric sequences in <i>Arabidopsis thaliana</i>

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American Journal of Molecular Biology 2012年第3期2卷 242-244页

作者： mar.a I. Vaquero-Sedas Miguel A. vega-Palas Instituto de Bioquímica Vegetal y Fotosíntesis CSIC-Universidad de Sevilla Seville Spain

We have previously described a simple method to analyze the chromatin structure of Arabidopsis telomeres independently of that of Interstitial Telomeric Sequences (ITSs). By using this method, we found that, whereas ITSs are heterochromatic, Arabidopsis telomeres exhibit euchromatic features [1]. Some concerns have been recently raised about the accuracy of this procedure [2]. Here, we summarize these concerns and justify our experimental approaches and interpretation of results.

关键词： Arabidopsis thaliana telomeres ITSs euchromatin heterochromatin

Frequently cutting restriction enzymes: Clearing the fog to see the ends

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American Journal of Molecular Biology 2013年第1期3卷 59-61页

作者： mar.a I. Vaquero-Sedas Miguel A. vega-Palas Institute of Vegetal Biochemistry and Photosynthesis CSIC-University of Seville Seville Spain

Telomeres, which are found at the ends of eukaryotic chromosomes, are composed of tandem arrays of repetitive sequences and safeguard genomic stability. Previous studies have revealed that telomeric repeats are also present at internal chromosomal loci in many eukaryotes. However, the biological role of these interstitial telomeric sequences (ITSs) remains unknown. The integrity of telomeric length and chromatin structure is required for telomere stability. However, the study of these telomeric features can be impeded by the presence of ITSs. Frequently cutting restriction enzymes have been revealed to be very useful tools for the study of the length and chromatin structure of telomeres independent of the presence of ITSs.

关键词： Telomeric Length Telomeric Chromatin Structure Frequently Cutting Restriction Enzymes Arabidopsis thaliana

Heuristics of node selection criteria to assess robustness of world airport network

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Chinese Journal of Aeronautics 2017年第4期30卷 1473-1480页

作者： Manel SORIA Oriol LORDAN Josmar.a SALLAN Department of Physics Aeronautics Engineering Universitat Politecnica de Catalunya-BarcelonaTech Terrassa 08222 Spain Department of Management Universitat Politecnica de Catalunya-BarcelonaTech Terrassa 08222 Spain

The world airport network（WAN） is one of the networked infrastructures that shape today＇s economic and social activity, so its resilience against incidents affecting the WAN is an important problem. In this paper, the robustness of air route networks is extended by defining and testing several heuristics to define selection criteria to detect the critical nodes of the *** addition to heuristics based on genetic algorithms and simulated annealing, custom heuristics based on node damage and node betweenness are defined. The most effective heuristic is a multiattack heuristic combining both custom heuristics. Results obtained are of importance not only for advance in the understanding of the structure of complex networks, but also for critical node detection.

关键词： Adaptive strategy Air route networks Complex networks Intentional attacks Network robustness

Cellular automata model for traffic flow with safe driving conditions

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Chinese Physics B 2014年第5期23卷 216-226页

作者： mar.a Elena Lárraga Luis Alvarez-Icaza Instituto de Ingeniería Universidad Nacional Autónoma de México04510Coyoacán D.F.México

In this paper, a recently introduced cellular automata （CA） model is used for a statistical analysis of the inner micro-scopic structure of synchronized traffic flow. The analysis focuses on the formation and dissolution of clusters or platoons of vehicles, as the mechanism that causes the presence of this synchronized traffic state with a high flow. This platoon formation is one of the most interesting phenomena observed in traffic flows and plays an important role both in manual and automated highway systems （AHS）. Simulation results, obtained from a single-lane system under periodic boundary conditions indicate that in the density region where the synchronized state is observed, most vehicles travel together in pla- toons with approximately the same speed and small spatial distances. The examination of velocity variations and individual vehicle gaps shows that the flow corresponding to the synchronized state is stable, safe and highly correlated. Moreover, results indicate that the observed platoon formation in real traffic is reproduced in simulations by the relation between vehicle headway and velocity that is embedded in the dynamics definition of the CA model.

关键词： traffic flow models synchronized traffic cellular automata platoons formation