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＂Fluidic Diode＂ for Passive Unidirectional Liquid Transport Bioinspired by the Spermathecae of Fleas

Journal of Bionic Engineering 2018年第1期15卷 42-56页

作者： gerda Buchberger Alexander Kogler Agnes Weth Richard Baumgartner Philipp Comanns Siegfried Bauer Werner Baumgartner Institute of Biomedical Mechatronics Johannes Kepler University Linz Altenberger Str. 69 A-4040 Linz Austria institute of Experimental Physics Department of Soft Matter Physics Johannes Kepler University Linz Altenberger Str. 69 A-4040 Linz Austria Institute of Biology II RWTH Aachen University Worringerweg 3 D-52074 Aachen Germany

We present a device for passive unidirectional liquid transport. The capillary channels used are bioinspired by the shape of the spermathecae （receptaculum seminis） of rabbit fleas （Spilopsyllus cuniculi） and rat fleas （Xenopsytla cheopis）. The spermatheca is an organ of female fleas that stores sperm until suitable conditions to lay eggs are found. We translated and multiplied the natural form and function of a spermatheca to create a continuous capillary system from which we designed our microfluidic device based directly on the model from nature. Applying the Young-Laplace equation, we derived a theoretical description of local liquid transport, which enables model-guided design. We arranged the bioinspired capillaries in parallel and engraved them in poly（methyl methacrylate）（PMMA） plates by CO2 laser ablation. The fabricated structures transport soapy water passively （i.e., without external energy input） in the forward direction at velocities of about 1 mm＇s i while halting the liquid fronts completely in the backward direction. The bio- inspired capillary channels are capable of unidirectional liquid transport against gravity. Distance and velocity measurements prove the feasibility of the concept. Unidirectional passive liquid transport might be advantageous in technical surfaces for liquid man- agement, for instance, in biomedical microfluidics, lab-on-chip, lubrication, electronics cooling and in micro-analysis devices.

关键词： liquid diode wetting passive unidirectional liquid transport capillary bioinspired

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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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Size and crystallinity effect on the ultrafast optical response of chemically synthesized silver nanoparticles

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Journal of Materiomics 2024年第3期10卷 594-600页

作者： Nadzeya Khinevich Domantas Peckus Asta Tamuleviciene gerda Klimaite Joel Henzie Tomas Tamulevicius Sigitas Tamulevicius Institute of Materials Science of Kaunas University of Technology K.Barsausko St.59LT-51423KaunasLithuania Department of Physics Kaunas University of TechnologyStudentu˛St.50LT-51368KaunasLithuania International Center for Materials Nanoarchitectonics(WPI-MANA) National Institute for Materials Science(NIMS)Tsukuba305-0044Japan

The excited localized surface plasmon(LSP)in metallic nanoparticles is known to relax through several processes such as electron-electron scattering,electron-phonon coupling,and phonon-phonon *** the current research,the ultrafast electron-phonon(e-ph)coupling relaxation processes for different average sizes and crystallinity of chemically synthesized silver nanoparticles were evaluated utilizing transient absorption *** nanoparticle size and crystallinity of similar linear dimension polycrystalline spherical and monocrystalline cubic nanoparticles ranging from ca.30-60 nm was related to their electron relaxation time constants and revealed very different *** the monocrystalline nanocubes,the electron-phonon coupling was not dependent on the cube edge length,while for the polycrystalline nanospheres,it was linearly decreasing with *** demonstrate that the e-ph coupling time constant could be used to evaluate crystallinity and crystallite size in plasmonic metal nanoparticles when the size(surface area)of the nanoparticle is known.

关键词： Silver nanospheres Silver nanocubes Electron-phonon coupling Transient absorption spectroscopy Crystallite size Polycrystalline structure

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Utilization of retired physicians as nursing faculty

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Open Journal of Nursing 2013年第7期3卷 481-484页

作者： Patricia L. Starck Shelly Liss gerda.gomez Michael E. Speer Department of Physical Medicine & Rehabilitation Baylor College of Medicine Houston USA Departments of Pediatrics & Ethics Baylor College of Medicine Houston USA The University of Texas Health Science Center-Houston School of Nursing Hou-ston USA

The nation’s nursing shortage is predicted to worsen, as nurses retire (supply) and more patients have access to care with the full enactment of the Affordable Care Act (demand). Schools of nursing are under continuing pressure to increase enrollment in entry level nursing programs [1-4]. Nurse educators have been engaged in a variety of creative and innovative projects to increase enrollment with some success. A primary reason for the lack of educational capacity is the shortage of nursing faculty [3-7]. The University of Texas Health Science Center-Houston School of Nursing undertook an innovative project to alleviate the nursing faculty shortage at that school. Working with a retired physician group, physician volunteers were solicited to teach in the laboratory portion of an undergraduate health assessment course. Twenty-two physicians volunteered in the first year in a class that involved forty baccalaureate students in their first-semester. The objectives of the project were twofold: First, to determine the suitability of retired physicians to serve as teachers of baccalaureate nursing students and second, ascertain possible monetary savings by using these physicians. Both of these goals were realized. The students valued the physicians’ enthusiasm, wisdom and experience and the cohort of physicians equaled the equivalent of four nursing faculty members. With an average annual faculty salary of $100,000, savings were significant.

关键词： Retired Physicians Supply and Demand Nursing Faculty Shortage

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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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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

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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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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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