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Multi-wavelength observations of the 2014 June 11 M3.9 flare: temporal and spatial characteristics

Research in Astronomy and Astrophysics 2019年第7期19卷 123-132页

作者： Damian J.Christian david Kuridze david b.jess Menoa Yousefi Mihalis Mathioudakis Department of Physics and Astronomy California State University NorthridgeNorthridgeCA 91330USA Institute of Mathematics Physics and Computer ScienceAberystwyth UniversityCeredigionCymruSY23 3UK Astrophysics Research Center School of Mathematics and PhysicsQueen's University BelfastBelfast BT7 INNUK

We present multi-wavelength observations of an M-class flare(M3.9) that occurred on 2014 June *** observations were conducted with the Dunn Solar Telescope(DST),employing adaptive optics,the multi-camera system Rapid Oscillations in Solar Atmosphere(ROSA),the new Hydrogen-Alpha Rapid Dynamics camera(HARDcam) in various wavelengths,such as Ca II K,Mg I b2(at 5172.7 A),and Hα narrow band and G-band continuum *** were re-constructed using the Kiepenheuer-Institut Speckle Interferometry Package(KISIP) code,to improve our image *** observed intensity increases of ≈120%–150% in the Mg,Ca K and Hα narrow band filters during the *** increases for the flare observed in the SDO EUV channels were several times larger,and the X-rays,as recorded by GOES,increased over a factor of 30 for the harder *** a modest delay was found between the onset of flare ribbons of a nearby sympathetic flare and the main flare ribbons observed in these narrow band *** peak flare emission occurred within a few seconds for the Ca K,Mg and Hα *** techniques indicate propagation velocities of ≈60 km s^-1 for the main flare ribbon and as high as300 km s^-1 for smaller regions,which we attribute to filament *** result and delays and velocities observed with SDO(≈100 km s^-1) for different coronal heights agree well with the simple model of energy propagation versus height,although a more detailed model for the flaring solar atmosphere is ***,we detected marginal quasi-periodic pulsations(QPPs) in the 40–60 s range for the Ca K,Mg and Hα bands,and such measurements are important for disentangling the detailed flare-physics.

关键词： magnetic reconnection-Sun flares-Sun atmosphere

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Dependence of Specific Impulse of Metal-free Formulations on CHNO-oxidizer′s Element Content and Enthalpy of Formation

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火炸药学报 2015年第4期38卷 1-4页

作者： david b.LEMPERT Institute of Problems of Chemical Physics of Russian Academy of Sciences Semenov av.1ChernogolovkaMoscow Region 142432 Russia

It is shown that it is not correct to estimate energetic characteristics of different compounds of solid composite propellants by evaluation of the specific impulse values of these components serving as an only component in the *** an approach may turn the researcher to a wrong *** has to compare compound′s potential in formulations close to real,*** least with necessary amount of *** of specific impulse upon element content of highenthalpy CHNO oxidizer,its enthalpy of formation,and kind of binder have been found.

关键词： solid composite propellants high-enthalpy oxidizer energetic parameters estimation specific impulse

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The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： Paul b.Wignall david P.G.bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

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Measuring,processing,and generating partially coherent light with self-configuring optics

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Light(Science & Applications) 2024年第11期13卷 2726-2733页

作者： Charles Roques-Carmes Shanhui Fan david A.b.Miller 1E.L.Ginzton Laboratory Stanford University348 Via PuebloStanfordCA 94305USA

Optical phenomena always display some degree of partial coherence between their respective degrees of *** coherence is of particular interest in multimodal systems,where classical and quantum correlations between spatial,polarization,and spectral degrees of freedom can lead to fascinating phenomena(e.g.,entanglement)and be leveraged for advanced imaging and sensing modalities(e.g.,in hyperspectral,polarization,and ghost imaging).Here,we present a universal method to analyze,process,and generate spatially partially coherent light in multimode systems by using self-configuring optical *** method relies on cascaded self-configuring layers whose average power outputs are sequentially *** optimized,the network separates the input light into its mutually incoherent components,which is formally equivalent to a diagonalization of the input density *** illustrate our method with numerical simulations of Mach-Zehnder interferometer arrays and show how this method can be used to perform partially coherent environmental light sensing,generation of multimode partially coherent light with arbitrary coherency matrices,and unscrambling of quantum optical *** provide guidelines for the experimental realization of this method,including the influence of losses,paving the way for self-configuring photonic devices that can automatically learn optimal modal representations of partially coherent light fields.

关键词： coherent modal generating

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Silk-based nerve guidance conduits with macroscopic holes modulate the vascularization of regenerating rat sciatic nerve

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Neural Regeneration Research 2025年第6期20卷 1789-1800页

作者： Carina Hromada Patrick Heimel Markus Kerbl LászlóGál Sylvia Nürnberger barbara Schaedl James Ferguson Nicole Swiadek Xavier Monforte Johannes C.Heinzel Antal Nógrádi Andreas H.Teuschl-Woller david Hercher Department Life Science Engineering University of Applied Sciences Technikum WienViennaAustria Austrian Cluster for Tissue Regeneration ViennaAustria Ludwig boltzmann Institute for Traumatology The Research Center in Cooperation with AUVAViennaAustria University Clinic of Dentistry Medical University of ViennaViennaAustria Department of Plastic Reconstructive and Aesthetic SurgeryLandesklinikum Wiener Neustadt2700 Wiener NeustadtAustria Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary Medical University of Vienna Department of Orthopedics and Trauma SurgeryDevision of Trauma SurgeryViennaAustria Department of Hand- PlasticReconstructive and Burn SurgeryBG Unfallklinik TuebingenUniversity of TuebingenTuebingenGermany

Peripheral nerve injuries induce a severe motor and sensory deficit. Since the availability of autologous nerve transplants for nerve repair is very limited, alternative treatment strategies are sought, including the use of tubular nerve guidance conduits(tNGCs). However, the use of tNGCs results in poor functional recovery and central necrosis of the regenerating tissue, which limits their application to short nerve lesion defects(typically shorter than 3 cm). Given the importance of vascularization in nerve regeneration, we hypothesized that enabling the growth of blood vessels from the surrounding tissue into the regenerating nerve within the tNGC would help eliminate necrotic processes and lead to improved regeneration. In this study, we reported the application of macroscopic holes into the tubular walls of silk-based tNGCs and compared the various features of these improved silk^(+) tNGCs with the tubes without holes(silk^(–) tNGCs) and autologous nerve transplants in an 8-mm sciatic nerve defect in rats. Using a combination of micro-computed tomography and histological analyses, we were able to prove that the use of silk^(+) tNGCs induced the growth of blood vessels from the adjacent tissue to the intraluminal neovascular formation. A significantly higher number of blood vessels in the silk^(+) group was found compared with autologous nerve transplants and silk^(–), accompanied by improved axon regeneration at the distal coaptation point compared with the silk^(–) tNGCs at 7 weeks postoperatively. In the 15-mm(critical size) sciatic nerve defect model, we again observed a distinct ingrowth of blood vessels through the tubular walls of silk^(+) tNGCs, but without improved functional recovery at 12 weeks postoperatively. Our data proves that macroporous tNGCs increase the vascular supply of regenerating nerves and facilitate improved axonal regeneration in a short-defect model but not in a critical-size defect model. This study suggests that further optimizatio

关键词： axon regeneration blood vessel functional recovery macroporous nerve lesion peripheral nerve repair sciatic nerve silk-based nerve guidance conduit vascularization

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Review of screening for pancreatic cancer in high risk individuals

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World Journal of Gastroenterology 2011年第19期17卷 2365-2371页

作者： Alina Stoita Ian D Penman david b Williams Department of Gastroenterology St Vincent's Hospital 390 Victoria StreetDarlinghurst2010NSWAustralia Centre for Liver and Digestive Disorders Royal Infirmary of Edinburgh51 Little France CrescentEdinburghEH16 4SAUnited Kingdom

Pancreatic cancer is difficult to diagnose at an early stage and is associated with a very poor *** percent of pancreatic cancers result from genetic susceptibility and/or familial *** from families with multiple affected first-degree relatives and those with a known cancer-causing genetic mutation have been shown to be at much higher risk of developing pancreatic *** efforts have focused on detecting disease at an earlier stage to improve survival in these high-risk *** article reviews high-risk groups,screening methods,and current screening programs and their results.

关键词： Pancreatic cancer Familial cancer Cancer screening Risk factors Endoscopic ultrasound Hereditary cancer

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Three-Dimensional Sub-100 nm Super-Resolution Imaging of biological Samples Using a Phase Ramp in the Objective Pupil

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Nano Research 2011年第6期4卷 589-598页

作者： david baddeley Mark b. Cannell Christian Soeller Department of Physiology University of Auckland Private Bag 92019 Auckland 1142 New Zealand

Localisation microscopy overcomes the diffraction limit by measuring the position of individual molecules to obtain optical images with a lateral resolution better than 30 nm. Single molecule localisation microscopy was originally demonstrated only in two dimensions but has recently been extended to three dimensions. Here we develop a new approach to three-dimensional （3D） localisation microscopy by engineering of the point-spread function （PSF） of a fluorescence microscope. by introducing a linear phase gradient between the two halves of the objective pupil plane the PSF is split into two lateral lobes whose relative position depends on defocus. Calculations suggested that the phase gradient resulting from the very small tolerances in parallelism of conventional slides made from float glass would be sufficient to generate a two-lobed PSF. We demonstrate that insertion of a suitably chosen microscope slide that occupies half the objective aperture combined with a novel fast fitting algorithm for 3D localisation estimation allows nanoscopic imaging with detail resolution well below 100 nm in all three dimensions （standard deviations of 20, 16, and 42 nm in x, y, and z directions, respectively）. The utility of the approach is shown by imaging the complex 3D distribution of microtubules in cardiac muscle cells that were stained with conventional near infrared fluorochromes. The straightforward optical setup, minimal hardware requirements and large axial localisation range make this approach suitable for many nanoscopic imaging applications.

关键词： Single molecules nanoscopy point-spread function engineering immunocytochemistry localisation microscopy

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Inhibiting the kynurenine pathway in spinal cord injury: multiple therapeutic potentials?

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Neural Regeneration Research 2018年第12期13卷 2073-2076页

作者： Kelly R.Jacobs david b.Lovejoy Neuroinflammation Group Centre for Motor Neuron Disease Research Department of Biomedical Sciences Faculty of Medicine and Health Sciences Macquarie University

Chronic induction of the kynurenine pathway（KP） contributes to neuroinflammation by producing the excitotoxin quinolinic acid（QUIN）. This has led to significant interest in the development of inhibitors of this pathway, particularly in the context of neurodegenerative disease. However, acute spinal cord injury（SCI） also results in deleterious increases in QUIN, as secondary inflammatory processes mediated largely by infiltrating macrophages, become predominant. QUIN mediates significant neurotoxicity primarily by excitotoxic stimulation of the N-methyl-D-aspartate receptor, but other mechanisms of QUIN toxicity are known. More recent focus has assessed the contribution that neuroinflammation and modulations in the KP make in mood and psychiatric disorders with recent studies linking inflammation and modulations in the KP, to impaired cognitive performance and depressed mood in SCI patients. We hypothesize that these findings suggest that in SCI, inhibition of QUIN production and other metabolites, may have multiple therapeutic modalities and further studies investigating this are warranted. However, for central nervous system-based conditions, achieving good blood-brain-barrier permeability continues to be a limitation of current KP inhibitors.

关键词： spinal cord injury neuroinflammation kynurenine pathway activated microglia infiltrating macrophages quinolinic acid neuropsychiatry depression

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Issues in the application of Digital Surface Model data to correct the terrain illumination effects in Landsat images

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International Journal of Digital Earth 2015年第3期8卷 235-257页

作者： Fuqin Li david L.b.Jupp Medhavy Thankappan National Earth Observation Group Geoscience AustraliaCanberraACTAustralia CSIRO Marine and Atmospheric ResearchCanberraACTAustralia

The accuracy of topographic correction of Landsat data based on a Digital Surface Model(DSM)depends on the quality,scale and spatial resolution of the DSM data used and the co-registration between the DSM and the satellite image.A physics-based bidirectional reflectance distribution function(bRDF)and atmospheric correction model in conjunction with a 1-second DSM was used to conduct the analysis in this *** results show that for the examples used from Australia,the 1-second DSM,can provide an effective product for this ***,it was found that some remaining artefacts in the DSM data,originally due to radar shadow,can still cause significant local errors in the *** they occur,false shadows and over-corrected surface reflectance factors can be *** generally,accurate co-registration between satellite images and DSM data was found to be critical for effective ***-registration by one or two pixels could lead to large errors of retrieved surface reflectance factors in gully and ridge *** low-resolution DSM data in conjunction with high-resolution satellite images will also fail to correct significant terrain components where they occur at the finer scales of the satellite *** resolution appropriate to the resolution of satellite image and the roughness of the terrain is needed for effective results,and the rougher the terrain,the more critical will be the accurate registration.

关键词： Digital Surface Models Landsat topographic correction mis-registration scale and resolution

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Mechanisms of Organelle Inheritance in Dividing Plant Cells

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Journal of Integrative Plant biology 2007年第8期49卷 1208-1218页

作者： Michael b Sheahan Ray J Rose david W McCurdy School of Environmental and Life Sciences The University of NewcastleCallaghan NSW 2308Australia Australian Research Council Centre of Excellence for Integrative Legume ResearchSchool of Environmental and Life SciencesThe University of NewcastleCallaghan NSW 2308Australia School of Environmental and Life Sciences The University of NewcastleCallaghan NSW 2308Australia

Organelles form essential compartments of all eukaryotic cells. Mechanisms that ensure the unbiased inheritance of organelles during cell division are therefore necessary to maintain the viability of future cell generations. Although inheritance of organelles represents a fundamental component of the cell cycle, surprisingly little is known about the underlying mechanisms that facilitate unbiased organelle inheritance. Evidence from a select number of studies, however, indicates that ordered organelle inheritance strategies exist in dividing cells of higher plants. The basic requirement for unbiased organelle inheritance is the duplication of organelle volume and distribution of the resulting organelle populations in a manner that facilitates unbiased partitioning of the organelle population to each daughter cell. Often, partitioning strategies are specific to the organelle, being influenced by the functional requirements of the organelle and whether the cells are mitotically active or re-entering into the cell cycle. Organelle partitioning mechanisms frequently depend on interactions with either the actin or microtubule cytoskeleton. In this focused review, we attempt to summarize key findings regarding organelle partitioning strategies in dividing cells of higher plants. We particularly concentrate on the role of the cytoskeleton in mediating unbiased organelle partitioning.

关键词： Actin cytoskeleton cell division green fluorescent protein-fimbrin AbD2 organelle partitioning protoplast

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