78 research outputs found
Feasibility analysis of applying microsatellite markers for individual identification in purebred and crossbred pigs
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Correlation of metal anode reversibility with solvation chemistry and interfacial electron transfer in aqueous electrolytes.
No full textReversible electrodeposition of metals is a crucial route to developing high-energy and rechargeable batteries. However, uncontrolled and nonplanar morphological evolution and parasitic reactions at the metal anodes are fundamental barriers to realizing full reversibility. Here, using aqueous electrochemistry as a probe, we develop multiscale characterization tools that can precisely determine the root cause of these morphological instabilities and parasitic reactions. Our analysis indicates that these issues are fundamentally from the free water molecules in aqueous electrolytes, leading to low reversibility of metal anodes. We therefore demonstrate a straightforward and effective strategy, based on modulating the solute anions in aqueous electrolytes, to suppress free water molecule concentration in conventional aqueous electrolytes. A proof of concept is demonstrated using a Zn metal anode, which shows unprecedented reversibility and stability in conventional aqueous electrolytes with structure-making anions under a harsh condition of 10 milliampere hours per square centimeter. This work unlocks an alternative angle to develop sustainable electrolytes for cost-efficient, practical battery chemistries.Funding: Research conducted in this study is funded by the King Abdullah University ofScience and technology (KAUSt). Author contributions: Y.Z. and h.n.A. conceived theproject. Y.Z. designed the experiments and conducted electrochemical tests and spectroscopicexperiments. S.t. performed theoretical simulations. t.W. fitted the tafel plots. Y.Z. andX.G. conducted operando nMR tests. Y.W. and c.l. performed electron microscopy. Y.Z. wrotethe manuscript with input from all authors. All authors approved the final version of thismanuscript. Competing interests: the authors declare that they have no competing interests
Images of the Dai : the aesthetics of gender and identity in Xishuangbanna
No full textThis thesis is based on fieldwork carried out m Xishuangbanna Dai Autonomous Prefecture, Yunnan Province, China. The main focus of the work is the Dai people, one of China's fifty-five so called 'Minority Nationalities'. I aim to paint a picture of the complex processes through which Dai ways of being and images of them are created and recreated. This is not to suggest that the Dai constitute a bounded group. Although Chinese official discourse presents a static, rigid picture of the so-called 'Minority Nationalities', I hope to have demonstrated that the everyday experiences of those in Banna are governed by a fluid and dynamic relationality. Images of 'Minority Nationalities' abound in China, these images are multiple and often contradictory. The Dai are known throughout China for their beauty, a beauty often portrayed as highly erotic. In this thesis I explore the implications of this image and the role of the Dai in its formation and continuity. With this in mind I examine the ways that the striking Dai aesthetic is used in the intricate power plays of Xishuangbanna. This work examines aspects of the Dai lived aesthetic and as such it has chapters on tattoo, architecture and feminine beauty. Dai aesthetic knowledge is interlaced with strands of moral, philosophical and cosmological insight, thus this work also includes a chapter on morality, autonomy and cooperation. The penultimate chapter uses vivid ethnography of the Water Splashing festival as a example of play of identities in Xishuangbanna. The Conclusion reiterates that the processes by which images, identities and aesthetic understandings are generated, and by which limits are explored and transgressed in Xishuangbanna are dialogic in character
Developmental exposure to non-dioxin-like polychlorinated biphenyls promotes sensory deficits and disrupts dopaminergic and GABAergic signaling in zebrafish
Full text link© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Brun, N. R., Panlilio, J. M., Zhang, K., Zhao, Y., Ivashkin, E., Stegeman, J. J., & Goldstone, J. Developmental exposure to non-dioxin-like polychlorinated biphenyls promotes sensory deficits and disrupts dopaminergic and GABAergic signaling in zebrafish. Communications Biology, 4(1), (2021): 1129, https://doi.org/10.1038/s42003-021-02626-9.The most abundant polychlorinated biphenyl (PCB) congeners found in the environment and in humans are neurotoxic. This is of particular concern for early life stages because the exposure of the more vulnerable developing nervous system to neurotoxic chemicals can result in neurobehavioral disorders. In this study, we uncover currently unknown links between PCB target mechanisms and neurobehavioral deficits using zebrafish as a vertebrate model. We investigated the effects of the abundant non-dioxin-like (NDL) congener PCB153 on neuronal morphology and synaptic transmission linked to the proper execution of a sensorimotor response. Zebrafish that were exposed during development to concentrations similar to those found in human cord blood and PCB contaminated sites showed a delay in startle response. Morphological and biochemical data demonstrate that even though PCB153-induced swelling of afferent sensory neurons, the disruption of dopaminergic and GABAergic signaling appears to contribute to PCB-induced motor deficits. A similar delay was observed for other NDL congeners but not for the potent dioxin-like congener PCB126. The effects on important and broadly conserved signaling mechanisms in vertebrates suggest that NDL PCBs may contribute to neurodevelopmental abnormalities in humans and increased selection pressures in vertebrate wildlife.This work was supported by the Swiss National Science Foundation P2EZP2_165200 (NRB), the Boston University Superfund Research Program NIH 5P42ES007381 (J.J.S. and J.V.G.), the Woods Hole Center for Oceans and Human Health (NIH: P01ES021923 and P01ES028938; NSF: OCE-1314642 and OCE-1840381) (N.R.B., J.M.P., and J.J.S.), and the National Natural Science Foundation of China 22006099 (K.Z. and Y.Z.) and the Shanghai Pujiang Program 19PJ1404900 (K.Z. and Y.Z.)
Sensitive All-Optical Channel-Drop Sensor in Photonic Crystals
No full textWe report the results of a study of an optical sensor based on a channel-drop technique with two cascaded cavities in photonic-crystal slabs. Quality factors and intensities of the resonant modes of the sensor were analyzed with three-dimensional simulations. With the introduction of a reflector in the bus-channel and by control of the coupling between the two cavities and the drop-channel, the drop efficiency can be remarkably increased. In addition to the simulation, the two cavity sensor is fabricated and tested for optical response to water and oil infiltration. Both direct visual imaging and quantitative analysis were applied in experiment. A difference of refractive index ?n = 0.12 between water and oil samples results in a wavelength shift of 18.3 nm, which greatly matches the simulation result of 20 nm and indicates a sensitivity of 153 nm RIU-1. Both resonant peaks for water and oil infiltration have good selectivity in their transmission spectrum. The contrast between the broadband output of the bus-channel and the highly wavelength-selective outputs of the drop-channel opens opportunities for the two cascaded-cavity system as a fundamental building block for a multiplex drop-channel array for all-optical sensing, which can be widely used for bio/chemical detection and environmental monitoring.BT/BiotechnologyApplied Science
Planarized nanophotonic sensor for real-time fluid sensing
Full text linkA planarized on-chip nanophotonic sensor based on a photonic crystal cavity is realized in this work. The sensor was embedded in a solid protecting material (flowable oxide) with perfect filled holes: this eliminates problems of fouling in practical applications. The functional area of the sensor is created by carefully removing the protecting material only on the top surface of the cavity. A wavelength shift of 7.5 nm was observed in experiment which is very close to a simulation result of 9.0 nm for sensing water (n=1.33) and crude oil (n=1.45) samples. Swift and accurate sensing was verified by a real-time dynamic measurement with rapidly alternating analytes in a microfluid channel
Molecular dynamics study of chemo-mechanical properties of asphalt binder
No full textAsphalt binder is an extensively used material as the paving surface of asphalt pavement. As is exposed to traffic load and environment, cracks are usually observed during the service life due to the mechanical damage. This dissertation aims at exploring molecular-level chemo-mechanical property of asphalt binder using molecular dynamics (MD) simulation. Atomistic models of asphalt binder were established, and SARA fractions were adopted to represent the chemical composition of asphalt binder. Several perspects of asphalt binder were investigated: (a) thermodynamics and rheological properties; (b) self-healing behaviors at nanoscale; (c) nanovoid initiation and propagation; (d) surface mechanical properties from AFM tapping.
The thermodynamics and rheological properties of asphalt binder, such as density, solubility parameters, radial distribution function, viscosity, and dynamic shear modulus were calculated under the help of molecular dynamics simulation. The results showed agreement to the experimental measurements, which validated the molecular models. The intrinsic self-healing behavior of asphalt binder was studied through the simulated failure-healing-failure test. The evolution of volume and surface area of nanovoids were proved to be related to the temperature, loading rate, SARA ratio and aging. The initiation location was found to be related to the local chemistry. AFM simulation found that the adhesion force and modulus are affected by simulation parameters. Contours of surface height and SARA concentration were plotted, which showed a strong correlation with the mechanical indicators.
This study indicated that utilization of molecular dynamics simulation brought about nanoscale perspective of the mechanical behavior for asphalt binder, which can further help to improve the fundamental understandings of this materials. The mechanical response can be further examined at nanoscale to add more basic knowledge. Furthermore, molecular dynamics simulation also brought new energy for studying the relationship between chemistry and mechanical properties. Overall, the utilization of molecular dynamics simulation is promising; it serves as the complement of the experiments, fulfills the gap between the mechanism and the behaviors.Ph.D.Includes bibliographical reference
Fairness in recommender systems
No full textAs one of the most pervasive applications of machine learning, recommender systems are playing an important role on assisting human decision making, which gives rise to essential concerns regarding the fairness of such systems. Research on fair machine learning has previously mainly focused on classification and ranking tasks. Although recommendation algorithm can usually be considered as a type of ranking algorithm, the fairness concerns in recommender systems are more complicated and should be extended to multiple stakeholders. In specific, different from only concerning item exposure fairness in ranking problem, we should also attach importance to the fairness demands of users in recommender systems. In this dissertation, we explore how to consider fairness requirements in the application of recommendation systems, and propose four works aiming to enhance user-side fairness in recommendation. The proposed works study fairness in recommendation from diverse and progressive perspectives. Experiments show that our fairness-aware methods can help enhance the fairness of recommender algorithms in various application scenarios.Ph.D.Includes bibliographical reference
Direct imaging of an inhomogeneous electric current distribution using the trajectory of magnetic half-skyrmions
No full textThe direct imaging of current density vector distributions in thin films has remained a daring challenge. Here, we report that an inhomogeneous current distribution can be mapped directly by the trajectories of magnetic half-skyrmions driven by an electrical current in Pt/Co/Ta trilayer, using polar magneto-optical Kerr microscopy. The half-skyrmion carries a topological charge of 0.5 due to the presence of Dzyaloshinskii-Moriya interaction, which leads to the half-skyrmion Hall effect. The Hall angle of half-skyrmions is independent of current density and can be reduced to as small as 4° by tuning the thickness of the Co layer. The Hall angle is so small that the elongation path of half-skyrmion approximately delineates the invisible current flow as demonstrated in both a continuous film and a curved track. Our work provides a practical technique to directly map inhomogeneous current distribution even in complex geometries for both fundamental research and industrial applications.This publication is based on research supported by the King Abdullah University of Science and Technology (KAUST), Office of Sponsored Research (OSR), under award nos. OSR-2016-CRG5-2977, OSR-2017-CRG6-3427, and CRF-2015-SENSORS-2708. X.Z. acknowledges the support by the Presidential Postdoctoral Fellowship of The Chinese University of Hong Kong, Shenzhen (CUHKSZ). Y.Z. acknowledges the support by the President’s Fund of CUHKSZ, Longgang Key Laboratory of Applied Spintronics, National Natural Science Foundation of China (grant no. 11574137), and Shenzhen Fundamental Research Fund (grant nos. JCYJ20160331164412545 and JCYJ20170410171958839).
W.W. acknowledge financial support by the National Key R&D Program of China (no. 2017YFA0303202). Author contributions: S.Z. and X.-X.Z. conceived and coordinated the project and analyzed the data. X.Z., J.X., and Y.Z. developed the theoretical model. Y.W. and S.Z. fabricated the samples, and S.Z. performed the MOKE measurements. S.Z., X.Z., and X.-X.Z. wrote the manuscript. The study was supervised by X.-X.Z. All authors contributed to the discussion and preparation of the manuscript. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors
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