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High levels of arbuscular mycorrhizal fungus colonization on Medicago truncatula reduces plant suitability as a host for pea aphids (Acyrthosiphon pisum)

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Insect science 2020年第1期27卷 99-112页

作者： Elisa Garzo Eric Rizzo Alberto Fereres s.karen gomez nstituto de Ciencias Agrarias-Consejo superior de Investigaciones Cientificas(ICA-CsIC) MadridSpain school of Biological sciences University of Northern ColoradoGreeleyColoradoUSA

This study sheds light on a poorly understood area in insect-plant-microbe interactions,focusing on aphid probing and feeding behavior on plants with varying levels of arbuscular mycorrhizal(AM)fungus root *** investigates a commonly occurring interaction of three species:pea aphid Acyrthosiphon pisum,barrel medic Medicago truncatula,and the AM fungus Rhizophagus irregularis,examining whether aphid-feeding behavior changes when insects feed on plants at different levels of AM fungus colonization(42% and 84% root length colonized).Aphid probing and feeding behavior was monitored throughout 8 h of recording using the electrical penetration graph(EPG)technique,also,foliar nutrient content and plant growth were ***,aphids took longer to reach their 1st sustained phloem ingestion on the 84% AM plants than on the 42% AM plants or on *** aphids showed phloem ingestion on the 84% AM plants relative to the 42% AM *** of the 84% AM plants had higher percent carbon(43.7%)relative to controls(40.5%),and the 84% AM plants had reduced percent nitrogen(5.3%)relative to the 42% AM plants(6%).In conclusion,EPG and foliar nutrient data support the hypothesis that modifications in plant anatomy(e.g.,thicker leaves),and poor food quality(reduced nitrogen)in the 84% AM plants contribute to reduced aphid success in locating phloem and ultimately to differences in phloem sap *** work suggests that *** plants benefit from AM symbiosis not only because of increased nutrient uptake but also because of reduced susceptibility to aphids.

关键词： Aphididae arbuscular mycorrhizal fungus electrical penetration graph(EPG) Fabaceae Glomeraceae insect-plant-microbe interactions symbiosis

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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

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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

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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

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Folded Mos2 layers with reduced interlayer coupling

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Nano Research 2014年第4期7卷 572-578页

作者： Andres Castellanos-gomez Herre s. J. van der Zant Gary A. steele Kavli Institute of Nanoscience Delft University of Technology 2528 CJ Delft The Netherlands

We study molybdenum disulfide （Mos2） structures generated by folding single-layer and bilayer Mos2 flakes. We find that this modified layer stacking leads to a decrease in the interlayer coupling and an enhancement of the photoluminescence emission yield. We additionally find that folded single-layer Mos2 structures show a contribution to photoluminescence spectra of both neutral and charged excitons, which is a characteristic feature of single-layer Mos2 that has not been observed in multilayer Mos2. The results presented here open the door to fabrication of multilayered Mos2 samples with high optical absorption while maintaining the advantageous enhanced photoluminescence emission of single-layer Mos2 by controllably twisting the Mos2 layers.

关键词： molybdenum disulfide(Mos2) folded Mos2 twisted Mos2 interlayer coupling Raman spectroscopy photoluminescence

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Assessment of laryngologists'ratings on physician review websites

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World Journal of Otorhinolaryngology-Head and Neck surgery 2024年第1期10卷 1-6页

作者： Meleeka Akbarpour karen Tawk Madelyn Frank Alizah s.gomez Navid Mostaghni Mehdi Abouzari Department of Otolaryngology-Head and Neck surgery University of CaliforniaIrvineUSA

Objective:To assess and characterize online ratings and comments on laryngologists and determine factors that correlate with higher ***:All the American Laryngological Association(ALA)members were queried across several online *** were normalized for comparison on a five-point Likert *** were categorized based on context and for positive/negative ***:Of the 331 ALA members,256(77%)were rated on at least one online *** all platforms,the average overall rating was 4.39±0.61(range:1.00-5.00).specific positive ratings including“bedside manners,”“diagnostic accuracy,”“adequate time spent with patient,”“appropriate follow-up,”and“physician timeliness”had significant positive correlations to overall ratings,by Pearson's correlation(Ps had significant negative correlations to overall ratings(Psion:Online ratings and comments for laryngologists are significantly influenced by patient perceptions of bedside manner,physician competence,and time spent with the patient.

关键词： laryngologist online rating patient rating physician review website

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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

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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

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The effect of the substrate on the Raman and photoluminescence emission of single-layer Mos2

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Nano Research 2014年第4期7卷 561-571页

作者： Michele Buscema Gary A. steele Herre s. J. van der Zant &ndres Castellanos-gomez Kavli Institute of Nanoscience Delft University of Technology Lorentzweg 1 2628 CJ Delft The Netherlands

We quantitatively study the Raman and photoluminescence （PL） emission from single-layer molybdenum disulfide （Mos2） on dielectric （siO2, hexagonal boron nitride, mica and the polymeric dielectric Gel-Film） and conducting substrates （Au and few-layer graphene）. We find that the substrate can affect the Raman and PL emission in a twofold manner. First, the absorption and emission intensities are strongly modulated by the constructive/destructive interference within the different substrates. second, the position of the Alg Raman mode peak and the spectral weight between neutral and charged excitons in the PL spectra are modified by the substrate. We attribute this effect to substrate-induced changes in the doping level and in the decay rates of the excitonic transitions. Our results provide a method to quantitatively study the Raman and PL emission from Mosa-based vertical heterostructures and represent the first step in ad hoc tuning the PL emission of 1L Mos2 by selecting the proper substrate.

关键词： molybdenum disulfide van der Waalsheterostructures Raman microscopy photoluminescenceenhancement photoluminescencequenching substrate effect

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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

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