We show evidence that left‐hand polarised electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere. Our unique set of ground and satellite ...observations shows coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The coincident precipitation was produced by wave‐particle interactions with EMIC waves near the plasmapause. The estimation of pitch angle diffusion coefficients supports that the observed EMIC waves caused coincident precipitation of both ions and relativistic electrons. This study clarifies that ions with energies of tens of keV affect the evolution of relativistic electrons in the radiation belts via cyclotron resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970′s.
Regional climate modeling addresses our need to understand and simulate climatic processes and phenomena unresolved in global models. This paper highlights examples of current approaches to and ...innovative uses of regional climate modeling that deepen understanding of the climate system. High-resolution models are generally more skillful in simulating extremes, such as heavy precipitation, strong winds, and severe storms. In addition, research has shown that finescale features such as mountains, coastlines, lakes, irrigation, land use, and urban heat islands can substantially influence a region’s climate and its response to changing forcings. Regional climate simulations explicitly simulating convection are now being performed, providing an opportunity to illuminate new physical behavior that previously was represented by parameterizations with large uncertainties. Regional and global models are both advancing toward higher resolution, as computational capacity increases. However, the resolution and ensemble size necessary to produce a sufficient statistical sample of these processes in global models has proven too costly for contemporary supercomputing systems. Regional climate models are thus indispensable tools that complement global models for understanding physical processes governing regional climate variability and change. The deeper understanding of regional climate processes also benefits stakeholders and policymakers who need physically robust, high-resolution climate information to guide societal responses to changing climate. Key scientific questions that will continue to require regional climate models, and opportunities are emerging for addressing those questions.
L-asparaginase has been used for more than three decades in acute lymphoblastic leukemia (ALL) patients and remains an essential drug in the treatment of ALL. Poor response to L-asparaginase is ...associated with increased risk of therapeutic failure in ALL. However, both the metabolic perturbation and molecular context of L-asparaginase-treated ALL cells has not been fully elucidated. Here we identify that treatment with L-asparaginase results in metabolic shutdown via the reduction of both glycolysis and oxidative phosphorylation, accompanied by mitochondrial damage and activation of autophagy. The autophagy is involved in reducing reactive oxygen species (ROS) level by eliminating injured mitochondria. Inhibition of autophagy enhances L-asparaginase-induced cytotoxicity and overcomes the acquired resistance to L-asparaginase in ALL cells. The ROS-p53-positive feedback loop is an essential mechanism of this synergistic cytotoxicity. Thus, our findings provide the rationale for the future development of combined treatment of L-asparaginase and anti-autophagy drug in ALL patients.
When two copper splats are in contact, a resistance to heat transfer exists between the splats. In thermal spraying, the conductivity of the coating is mainly reduced by non-metallic bonds at ...internal interfaces and trapped oxides. In cold spraying, however, almost no oxidation occurs during spraying. To demonstrate the capabilities and advantages of Cold Spray for the manufacturing of a conductive copper coating, the present study is focused at comparing the different processing methods in the as-sprayed and the annealed state. As a result, the coatings sprayed with spherical copper particles showed superior thermal conductive characteristics than coatings sprayed with non-spherical particles. There was a critical annealing temperature giving the maximum thermal conductivity. Up to a critical temperature, the annealing process enhanced the thermal conduction between adjacent splats. But, over that temperature, the voids in the coating rearrange and concentrate along the grain boundaries.
► Dense copper coating by cold spray process. ► Features of copper coating affected by feedstock morphology. ► Optimal thermal conductivity achieved by spherical feedstock and subsequent annealing at 300–400
°C. ► Grain growth is more effective to enhance the thermal conduction of copper.
There has been increasing evidence for pitch angle scattering of relativistic electrons by electromagnetic ion cyclotron (EMIC) waves. Theoretical studies have predicted that the loss time scale of ...MeV electrons by EMIC waves can be very fast, suggesting that MeV electron fluxes rapidly decrease in association with the EMIC wave activity. This study reports on a unique event of MeV electron loss induced by EMIC waves based on Arase, Van Allen Probes, and ground‐based network observations. Arase observed a signature of MeV electron loss by EMIC waves, and the satellite and ground‐based observations constrained spatial‐temporal variations of the EMIC wave activity during the loss event. Multisatellite observation of MeV electron fluxes showed that ~2.5‐MeV electron fluxes substantially decreased within a few tens of minutes where the EMIC waves were present. The present study provides an observational estimate of the loss time scale of MeV electrons by EMIC waves.
Plain Language Summary
This paper shows an observational evidence that electromagnetic ion cyclotron (EMIC) waves cause rapid loss of high‐energy electrons in the Earth's radiation belt. The radiation belt contains highly energetic electrons with energies above 1 Mega‐electron volt (MeV), and the number of the electrons dramatically changes during geomagnetic storms. Radiation belt electron fluxes decrease orders of magnitude during the early stage of storms, and it is of interest to clarify mechanisms which are responsible for the loss of radiation belt electrons. EMIC waves are considered as an important driver of loss of radiation belt, and theoretical estimates suggest that radiation belt electrons are rapidly lost immediately after generation of EMIC waves. This paper gives observational support for the theoretical prediction using the satellite and ground‐based network observations. The Arase satellite and Van Allen Probes measure variations in radiation belt electrons. The excitation timing and spatial‐temporal evolution of EMIC waves are determined by using the worldwide ground‐based network measurements in concert with the Van Allen Probes and the Arase satellite. We demonstrate that ~2.5‐MeV electrons are lost within 10 min after the generation of the EMIC waves, which is much faster than that reported previous observational studies.
Key Points
The Arase satellite observed loss of MeV electrons in association with the activation of EMIC waves
Spatial‐temporal variations of the EMIC wave activity are constrained by ground‐based and satellite observations
Multi‐instrument observations show loss of ~2.5‐MeV electrons due to EMIC waves occurred within 10 min
Cloning, through somatic cell nuclear transfer (SCNT), has the potential for a large expansion of genetically favorable traits in a population in a relatively short term. In the present study we ...aimed to produce multiple cloned camels from racing, show and dairy exemplars. We compared several parameters including oocyte source, donor cell and breed differences, transfer methods, embryo formation and pregnancy rates and maintenance following SCNT. We successfully achieved 47 pregnancies, 28 births and 19 cloned offspring who are at present healthy and have developed normally. Here we report cloned camels from surgical embryo transfer and correlate blastocyst formation rates with the ability to achieve pregnancies. We found no difference in the parameters affecting production of clones by camel breed, and show clear differences on oocyte source in cloning outcomes. Taken together we demonstrate that large scale cloning of camels is possible and that further improvements can be achieved.
A new molecular imprinting technique using covalently immobilized hemoglobin (Hb) is described for creating Hb-specific recognition cavities on silica. Two kinds of organic silane ...(3-aminopropyltrimethoxysilane: APTMS, and trimethoxypropylsilane: TMPS) were polymerized on a surface of porous silica after the Hb template was covalently immobilized by forming imine bonds, and their influence was analyzed. The results showed that not only the silane amount but also the relative proportions play an important role in protein imprinting. Pore size distribution on Hb imprinted silica was determined by nitrogen adsorption/desorption after removing the template Hb. The Hb-imprinted silica using covalently immobilized Hb (MIPi) as a template proved superior to silica using free Hb (MIPf) regarding displacement of template Hb, and selective re-adsorption as compared with other non-template proteins. The results suggested the capacity for selective adsorption of MIPi to be not only based on the isoelectric point (pI) and protein molecular weight, but also the characteristics of protein recognition cavities imprinted on base silica.
Recent works have attempted to extract features such as road markings from sparse mobile LiDAR scanning point cloud-derived images via convolutional neural networks (CNN). In this paper, the use of ...such methods for ground segmentation was explored. To begin, point clouds from each channel will be projected onto the y-z plane to generate the images that will be used for training and testing the CNN model. Then, for the main workflow, the following steps were performed for each channel: (1) point cloud-to-image conversion; (2) CNN classification; and (3) image-to-point cloud projection. Then utilizing multi-threading, each channel is processed in parallel to generate our ground-segmented sparse point cloud. Our findings have shown successful ground segmentation, achieving an f1-score of 98.9%. However, it performed 27.81% slower as compared to RANSAC. Overall, this initial investigation has demonstrated that ground segmentation from sparse point cloud-derived imagery is possible, and with further improvements to the CNN model, to make it faster, it has good potential to act as an alternative to conventional point cloud processing.
PDF
