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Journal of Forestry Research 2020年第5期31卷 1759-1771页

作者： Luis A.Leon-Banuelos Angel R.Endara-Agramont william gomez-demetrio Carlos G.Martınez-Garcıa E.Gabino Nava-Bernal 50000 TolucaMexicoMexico

The identification of forests infested by parasitic plants is important for the design of appropriate control and prevention *** images and geographic information systems are commonly used to analyze the presence of pest and parasitic plants in the *** there is a need for finer *** the last decade,the use of unmanned aerial vehicles has become increasingly common for capturing aerial images(<10 cm per pixel).The objective of the study was to obtain RGB values(Red,Green and Blue)through the colorimetric ranges for use in identification of Yellow Dwarf Mistletoe(YDM)(Arceuthobium globosum)in aerial images taken in a forest of central Mexico via a programmed *** tonalities of YDM were classified according to its phenological stages,***(young stage),yellow(adult stage),and brown(senescence stage),considering two light intensities,sunny and ***-parametric tests were used in statistical *** Spearman test showed significant negative correlation(p<0.001)between phenological stage and colour,indicating that lower RGB values were associated with greater *** differences between groups were analysed using Kruskal–Wallis(p<0.01)and Mann–Whitney tests(p<0.01).The applied algorithm identified the presence and predominant colours of YDM according to its phenological stage.

关键词： Colorimetric analysis RGB Pinus hartweggi Parasitic plants Remote sensing

The effect of rippling on the mechanical properties of graphene

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Nano Materials Science 2022年第1期4卷 18-26页

作者： Guillermo Lopez-Polin Cristina gomez-Navarro Julio gomez-Herrero Instituto de Ciencia de Materiales de Madrid CSICMadrid E 28049Spain Departamento de Física de La Materia Condensada Universidad Autónoma de MadridMadridE-28049Spain IFIMAC Condensed Matter Physics Center(IFIMAC).Universidad Autónoma de Madrid MadridE-28049Spain

Graphene is the stiffest material known so far but, due to its one-atom thickness, it is also very ***, free-standing graphene exhibit ripples that has major effects on its elastic properties. Here we will summarize three experiments where the influence of rippling is essential to address the results. Firstly, we observed that atomic vacancies lessen the negative thermal expansion coefficient(TEC) of free-standing *** also observed an increase of the Young's modulus with global applied strain and with the introduction of small density defects that we attributed to the decrease of rippling. Here, we will focus on a surprising feature observed in the data: the experiments consistently indicate that only the rippling with wavelengths between 5 and 10 nm influences the mechanics of graphene. The rippling responsible of the negative TEC and anomalous elasticity is thought to be dynamic, i.e. flexural phonons. However, flexural phonons with these wavelengths should have minor effects on the mechanics of graphene, therefore other mechanisms must be considered to address our observations. We propose static ripples as one of the key elements to correctly understand the thermomechanics of graphene and suggest that rippling arises naturally due to a competition of symmetry breaking and anharmonic fluctuations.

关键词： Graphene Mechanical properties Atomic force microscopy Defects Ripples Stmain

On the material dependence of experimental shear fracture orientation

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Science China Earth Sciences 2015年第12期58卷 2357-2362页

作者： Enrique gomez-RIVAS Albert GRIERA Department of Geology and Petroleum Geology School of Geosciences King’s College University of Aberdeen Departament de Geologia Universitat Autònoma de Barcelona

It is not uncommon to observe shear fractures in ductile rocks oriented at more than 45° with respect to the maximum compression direction. Since these orientations cannot be explained with the classic Mohr-Coulumb or Tresca yield criteria, Zheng et al.(Journal of Structural Geology, 35: 1394–1405, 2011) proposed the maximum effective moment(MEM) failure criterion. This rule suggests that shear fractures in ductile rocks form at ?55° with the maximum compression axis and that this orientation is material-independent and, therefore, universal. Zheng et al.(Science China: Earth Sciences, 57(11): 2819–2824, 2014) used data from our own experiments as supporting evidence of their failure criterion. In this contribution we discuss why shear fracture formation in ductile rocks indeed strongly depends on the mechanical properties of the deforming medium, and why experimental data should not be taken to prove the validity of the MEM criterion. The formation mechanisms and orientations of shear fractures in our experiments significantly vary depending on the material strength and degree and type of anisotropy(composite and intrinsic). We therefore demonstrate using experimental data that a universal failure angle in ductile and anisotropic rocks does not apply. Additionally, we highlight some inconsistencies of the MEM criterion.

关键词： shear fracture anisotropy fracture orientation material properties failure criteria ductile deformation

Excitatory synapse impairment and mitochondrial dysfunction in Huntington’s disease: heat shock factor 1 (HSF1) converging mechanisms

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Neural Regeneration Research 2020年第1期15卷 69-70页

作者： Nicole Zarate Rocio gomez-Pastor Department of Neuroscience School of Medicine University of Minnesota

Heat shock factor 1(HSF1)is abnormally degraded in Huntington’s disease(HD):HD is a neurodegenerative disorder characterized by severe cognitive and motor *** is caused by a CAG repeat expansion within exon 1 of the huntingtin(HTT)gene(The Huntington’s Disease Collaborative Research Group,1993).These expansions lead to the production of an aberrant mutant huntingtin protein(mHTT)that is prone to misfolding and *** and aggregation of mHTT is present in virtually all cell types in the body but preferentially affects medium spiny neurons of the striatum,a brain region that controls movement and some forms of *** of mHTT leads to,but not only,transcriptional dysregulation,DNA damage,mitochondrial dysfunction and excitatory synaptic failure ultimately causing neuronal ***,the molecular mechanisms by which mHTT exerts these defects are still unclear.

关键词： Huntington impairment shock

Contribution of purinergic receptors to spinal cord injury repair:stem cellbased neuroregeneration

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Neural Regeneration Research 2016年第3期11卷 418-419页

作者： Rosa gomez-Villafuertes Department of Biochemistry and Molecular Biology IV Veterinary SchoolUniversidad Complutense of Madrid

Traumatic spinal cord injury（SCI）,defined as physical trauma to the spinal column yielding altered motor,sensory,or autonomic function,is a devastating neurological disease causing major impact at both personal and societal *** is characterized by a primary insult（compression,contusion or laceration）followed by a secondary pathologicalcascade that propagates further injury disrupting motor,

关键词： repair devastating progenitor autonomic neurological altered sensory trauma yielding embryonic

A generalization of the half-normal distribution

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Applied Mathematics(A Journal of Chinese Universities) 2016年第4期31卷 409-424页

作者： Yolanda M. gomez Ignacio Vidal departamento de matemáticas facultad de ciencias universidad de católica del norte Antofagasta Chile instituto de matemática y física universidad de talca Chile

In this paper we introduce an extension of the half-normal distribution in order to model a great variety of non-negative data. Its hazard rate function can be decreasing or increasing, depending on its parameters. Some properties of this new distribution are presented. For example, we give a general expression for the moments and a stochastic representation. Also, the cumulative distribution function, the hazard rate function, the survival function and the quantile function can be easily evaluated. Maximum likelihood estimators can be computed by using numerical procedures. Finally, a real-life dataset has been presented to illustrate its applicability.

关键词： half-normal distribution generalized half-normal distribution maximum likelihood estimate

Biaxial versus uniaxial strain tuning of single-layer MoS_(2)

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Nano Materials Science 2022年第1期4卷 44-51页

作者： Felix Carrascoso Riccardo Frisenda Andres Castellanos-gomez Materials Science Factory Instituto de Ciencia de Materiales de Madrid(ICMM-CSIC)28049Madrid Spain

Strain engineering has arisen as a powerful technique to tune the electronic and optical properties of twod imensional semiconductors like molybdenum disulfide(MoS_(2)).Although several theoretical works predicted that biaxial strain would be more effective than uniaxial strain to tune the band structure of MoS_(2),a direct experimental verification is still missing in the *** we implemented a simple experimental setup that allows to apply biaxial strain through the bending of a cruciform polymer *** used the setup to study the effect of biaxial strain on the differential reflectance spectra of 12 single-layer MoS_(2)flakes finding a redshift of the excitonic features at a rate between-40 meV/%and-110 meV/%of biaxial *** also directly compare the effect of biaxi al and uniaxial strain on the same single-layer MoS_(2)finding that the biaxial strain gauge factor is 2.3 times larger than the uniaxial strain one.

关键词： finding layer gauge

A CFD study of the transport and fate of airborne droplets in a ventilated office:The role of droplet−droplet interactions

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Frontiers of Environmental Science & Engineering 2022年第3期16卷 49-62页

作者： Allan gomez-Flores Gukhwa Hwang Sadia Ilyas Hyunjung Kim Department of Environment and Energy Jeonbuk National UniversityJeonju Jeonbuk 54896Republic of Korea Department of Mineral Resources and Energy Engineering Jeonbuk National UniversityJeonju Jeonbuk 54896Republic of Korea

Previous studies reported that specially designed ventilation systems provide good air quality and safe environment by removing airborne droplets that contain viruses expelled by infected *** water droplets can be stable in the environment and remain suspended in air for prolonged *** between droplets may occur and droplet interactions should be ***,the previous studies focused on other physical phenomena(air flow,drag force,evaporation)for droplet transport and neglected droplet *** this work,we used computational fluid dynamics(CFD)to simulate the transport and fate of airborne droplets expelled by an asymptomatic person and considered droplet *** drag with turbulence for prediction of transport and fate of droplets indicated that the turbulence increased the transport of 1μm droplets,whereas it decreased the transport of 50μm *** contrast to only considering drag and turbulence,consideration of droplet interactions tended to increase both the transport and *** the length scale of the office is much larger than the droplet sizes,the droplet interactions,which occurred at the initial stages of release when droplet separation distances were shorter,had a significant effect in droplet fate by considerably manipulating the final locations on surfaces where droplets ***,it is proposed that when an exact prediction of transport and fate is required,especially for high droplet concentrations,the effects of droplet interactions should not be ignored.

关键词： Droplet interactions Aerosols Colloids CFD Transport Fate

Strain engineering in single-,bi-and tri-layer MoS_(2),MoSe_(2),WS_(2)and WSe_(2)

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Nano Research 2021年第6期14卷 1698-1703页

作者： Felix Carrascoso Hao Li Riccardo Frisenda Andres Castellanos-gomez Materials Science Factory Instituto de Ciencia de Materiales de MadridConsejo Superior de Investigaciones Cientificas28049MadridSpain

Strain is a powerful tool to modify the optical properties of semiconducting transition metal dichalcogenides like MoS_(2),MoSe_(2),WS_(2) and WSe_(2).In this work we provide a thorough description of the technical details to perform uniaxial strain measurements on these two-dimensional semiconductors and we provide a straightforward calibration method to determine the amount of applied strain with high *** then employ reflectance spectroscopy to analyze the strain tunability of the electronic properties of single-,bi-and tri-layer MoS_(2),MoSe_(2),WS_(2) and WSe_(2).Finally,we quantify the flake-to-flake variability by analyzing 15 different single-layer MoS_(2) flakes.

关键词： two-dimensional(2D)materials transition metal dichalcogenides strain engineering band gap differential reflectance

Quercetin prevents spinal motor neuron degeneration induced by chronic excitotoxic stimulus by a sirtuin 1-dependent mechanism

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Translational Neurodegeneration 2017年第1期6卷 310-323页

作者： Rafael Lazo-gomez Ricardo Tapia División de Neurociencias Instituto de Fisiología CelularUniversidad Nacional Autónoma de MéxicoCircuito exterior s/nCiudad UniversitariaCoyoacán04510 Ciudad de MéxicoMexico

Background:Excitotoxicity is a mechanism of foremost importance in the selective motor neuron degeneration characteristic of motor neuron *** therapeutic strategies are an unmet need for these ***,such as quercetin and resveratrol,are plant-derived compounds that activate sirtuins(SIRTs)and have shown promising results in some models of neuronal death,although their effects have been scarcely tested in models of motor neuron ***:In this work we investigated the effects of quercetin and resveratrol in an in vivo model of excitotoxic motor neuron death induced by the chronic infusion ofα-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid(AMPA)into the rat spinal cord *** and resveratrol were co-infused with AMPA and motor behavior and muscle strength were assessed daily for up to ten ***,animals were fixed and lumbar spinal cord tissue was analyzed by histological and immunocytological ***:We found that the chronic infusion of AMPA[1 mM]caused a progressive motor neuron degeneration,accompanied by astrogliosis and microgliosis,and motor deficits and paralysis of the rear *** infusion ameliorated AMPA-induced paralysis,rescued motor neurons,and prevented both astrogliosis and microgliosis,and these protective effects were prevented by EX527,a very selective SIRT1 *** contrast,neither resveratrol nor EX527 alone improved motor behavior deficits or reduced motor neuron degeneration,albeit both reduced ***:These results suggest that quercetin exerts its beneficial effects through a SIRT1-mediated mechanism,and thus SIRT1 plays an important role in excitotoxic neurodegeneration and therefore its pharmacological modulation might provide opportunities for therapy in motor neuron disorders.

关键词： Motor neuron disorder Quercetin Resveratrol Sirtuin Excitotoxicity