bluuebunny/crossref_metadata_2025 huggingface dataset:
Looking at Proteins Interacting and Folding inside Cells
Authors: Carmichael Stephen W
Published: May 2018

Fluorescence microscopy has revolutionized cell biology. Not only has it increased the spatial resolution with which certain processes are visualized, but it has allowed microscopists to monitor more than one event at a time. One of the remaining challenges is to see how proteins fold and assume their native conformations within living cells. Recently, Nathan Luedtke, Rachel Dexter, Daniel Fried, and Alanna Schepartz have demonstrated a technique to demonstrate these events in situ.
Life In and Under the Antarctic Ice Sheets
Authors: Doyle Shawn , Amato Pierre , Christner Brent
Published: May 2018

The discovery of viable microbial life in ancient glacial ice has opened up a plethora of questions related to how life can be sustained in such extreme environments. Cryo-microscopic analysis of lab prepared ice samples indicates that microbes are located in the small veins of water that exist between individual ice crystals. Crucial to these studies is to obtain an understanding of the physicochemical habitat for life through physiological and microscopic analysis.
Signature Analysis applied to EDS microanalysis
Authors: Colby J W , Ward D C
Published: May 2018

Most spectroscopies (FTIR, XRD, RAMAN, MS, etc.), were developed in order to identify materials. This is accomplished by capturing the spectral “signature” of an unknown and matching it to those of a comprehensive database of reference materials. Development of these spectroscopies has included efforts to embellish the associated database. EDS evolved as a resource to provide qual/quant, and development has been to improve the accuracy of quantation. Until recently, EDS was not considered a spectroscopy to provide identification of materials.
Surface Preparation of Uranium by Ion Milling
Authors: Carpenter Donald A , Bridges Robert L
Published: May 2018

Metallographic examinations of uranium, as carried out with both optical and orientation contrast microscopies (electron backscatter diffraction or EBSD), typically require a final preparation step that involves acid-etching or electropolishing. Uranium oxidizes relatively rapidly after mechanical polishing, making EBSD impossible without additional preparation steps. Conventional specimen preparation generates a mixture of acids and radioactive waste, so-called “mixed waste” as defined by the Resource Conservation and Recovery Act (RCRA). Mixed waste is more costly to dispose of than either separate component and there is a desire to eliminate mixed waste streams. One simple method to avoid the use of acids in optical metallography is to wait a few minutes for the sample to differentially oxidize to obtain the desired contrast. However, this method is disadvantageous when more than a few micrographs are needed because the sample continues to change with each micrograph.
Extreme High-Resolution SEM: A Paradigm Shift
Authors: Young Richard , Templeton Todd , Roussel Laurent , Gestmann Ingo , van Veen Gerard , Dingle Trevor , Henstra Sander
Published: May 2018

“Extreme high-resolution” (XHR) scanning electron microscopy (SEM) has the potential to change the way we look at SEM. Anyone in the SEM world knows that you don't do high-resolution SEM at low accelerating voltages because of chromatic aberration limitations. The XHR design offers a new way to deal with chromatic aberration and realize the huge benefit of reduced beam penetration.

The new Magellan 400 SEM family is the first to offer subnanometer resolution over the entire electron energy range from 1 keV to 30 keV, effectively establishing a new performance category known as XHR SEM (Figure 1). To achieve this unprecedented performance, the Magellan combines novel electron optical design elements with technologies developed for the industry-leading Titan (scanning) transmission electron microscope (S/TEM) and DualBeam (focused ion /SEM) platforms.
A New Perspective on Mechanical Testing: In Situ Compression in the TEM
Authors: Nowak Julia Deneen , Shan Zhiwei , Warren Oden L
Published: May 2018

Testing the mechanical properties of nanoscale materials faces a number of inherent challenges. As the size of the “target” decreases, the inability to actually see what occurs during testing can be troublesome. While a number of studies have attempted to characterize the mechanical response of nanoscale materials using traditional nanoindentation techniques, certain lingering questions have always remained. For example, the nature and sequence of failure events in the case of multilayer films has long been the subject of scientific debate. Similarly, in the case of individual nanoparticles, it is often difficult to ascertain that contact was both made and maintained throughout the test. Further, the crystallographic orientation of the sample and/or the presence of preexisting defects, which can have a significant influence on mechanical properties at the nanoscale, typically remain unknown.
A Scanning Tunneling Microscope as a Switch in a Nanocomputer
Authors: Carmichael Stephen W
Published: May 2018

There are several “molecular machines” that have been devised on a nanometer scale, made from proteins, DNA, and other molecules. A molecular machine is a system that generates physical forces at the atomic level, controlled by an external stimulus. Since all of the proposed circuits connect components linearly, they only communicate with one machine at a time. Now, Anirban Bandyopadhyay and Somobrata Acharya have devised an ingenious device that has the potential to communicate different instructions to many molecular machines simultaneously. They demonstrated that 2,3,5,6-tetramethyl-1–4-benzoquinone (duroquinone; DRQ) can be assembled as 17 identical molecules, one central molecule surrounded radially by 16 others. The central molecule can control the conformation of all the others when switched to one of four logic states by suitable pulses from an atomic sharp needle of a scanning tunneling microscope (STM).
Atom-Probe Microscopy LEAPs the Chasm to Mainstream Applications
Authors: Alvis Roger , Kelly Thomas F
Published: May 2018

In the now classic marketing text, Crossing the Chasm, Geoffrey Moore describes the difficult transition every successful new technology must make as it evolves from laboratory curiosity to mainstream acceptance. Essentially the transition consists of a radical shift in focus, from exploring the possibilities that fill the minds of visionaries and innovators to satisfying the practical concerns of pragmatists and conservatives who are more interested in integration with existing technologies and return on investment. Initial development of the atom probe was motivated primarily by scientific curiosity and the desire to do novel research with a new microscopy technique. As the technology matured the focus of development efforts shifted to expanding the applications space and improving practical performance in areas such as sensitivity, fidelity, productivity, and ease of use.
Using EBSD to Map Domain Structures in Ferroelectrics
Authors: MacLaren Ian , Farooq Muhammad Umar , Villaurrutia Rafael
Published: May 2018

Electron backscatter diffraction (EBSD) has undergone a rapid transformation in the past 15 years from a curiosity and a minority interest into an important part of our arsenal of microstructure characterisation techniques. In this time, it has been very widely applied in metallurgy, especially in understanding the influence of processing on local crystallographic textures and on boundary populations. More recently, it has been used in a diverse range of different fields including semiconductors, ceramics, geological materials and even palaeontology. In this article we will show how EBSD can yield invaluable information about domain structures in ferroelectrics.
Multicolor Contrast Effects by Monochromatic Astronomic Filters – Utilization in Light Microscopy and Photomicrography
Authors: Piper Jörg
Published: May 2018

Several color filters have been developed for astronomic use in order to improve image quality in visual observations and astronomic photography. Various positive effects, which can be achieved in astronomic practice, have already been described by several authors, manufacturers and distributors [2, 4, 5, 9, 10, 12]. Monochromatic narrow-band filters are widely used by astronomers. These filters are constructed as interference filters; they select small ranges within the spectrum of the visible light corresponding with characteristic radiation emitted by celestial nebula or the sun and its protuberances. This way, scattered terrestrial radiation caused by “light pollution” and non visible infrared or ultraviolet spectral components are blocked. Fundamental improvements of image quality will result from these filters when refractors or reflector telescopes are fitted with them.
Online Microscopy Lab Training Modules in an Academic Environment
Authors: Schierbeek K , Mikel A , Hill S E , Mills O P
Published: May 2018

The Applied Chemical and Morphological Analysis Laboratory (ACMAL) is a multi-user, multi-disciplinary characterization laboratory. ACMAL houses two scanning electron microscopes (SEM and FE-SEM), a transmission electron microscope (TEM), focused ion beam milling system (FIB), four X-ray diffractometers, and an X-ray fluorescence spectrometer. ACMAL operates as a recharge center where users absorb facility operation cost through an hourly use fee. As such, we are keenly interested in encouraging broad access to the facility by lowering obstacles to users. Facility training enhancements provide the best pathway to productive and responsible facility usage.
STORM Offers Super-Resolution in 3D!
Authors: Carmichael Stephen W
Published: May 2018

For the first few centuries of microscopy, spatial resolution was limited by the diffraction barrier. Recently, this barrier has been broken using several different methods. Optical methods that provide better resolution than the diffraction barrier are referred to as super-resolution. Although these techniques have significantly improved resolution in two dimensions (x and y) or in the axial dimension (z), it has not been possible to achieve substantial improvement in all three dimensions simultaneously. A study by Bo Huang, Wenqin Wang, Mark Bates, and Xiaowei Zhuang demonstrated a breakthrough by achieving a spatial resolution that is 10 times better than the diffraction limit in all three dimensions without using sample or optical-beam scanning.
Novel Life Science Tensile Stage Integration with Cryo Dual-Beam FIB Technology
Authors: Sherman Debra M
Published: May 2018

Soft and hydrated samples present unique challenges when determining structural integrity. Mechanical strength may be a critical factor in evaluating the sample in question. For example, genetic manipulation can change the chemical composition of plant cell walls. One goal would be producing strong plants whose stems and leaves lend themselves to easy break down for the production of ethanol. Arabidopsis is an ideal test sample for cell wall manipulation since the genetic strains are so well documented. However, these plants are quite small and mechanically testing the integrity of the walls can be problematic in the laboratory setting.
Progress In Design and Applications Of CCD Cameras For Electron Microscopy
Authors: Downing Kenneth H
Published: May 2018

Over the last several years the long-awaited revolution in direct-digital readout systems has begun, with the introduction of efficient slow-scan CCD cameras. Earlier, the introduction of video cameras to electron microscopes had brought a quantum leap in the speed and efficiency of carrying out a host of operations. The high sensitivity of the video cameras provided the ability to see the image in much more detail and at a lower beam intensity than had been previously possible by viewing the fluorescent screen. The ability to assess, on line, characteristics such as specimen quality and image focus, even qualitatively, gave feedback to the operator that previously took hours to obtain. Due to the low resolution of these video systems, however, they were rarely useful for data recording.
Indizierte Prävention von Rechenschwächen im Vorschulalter: Effekte bis Klasse 3
Authors: Moraske Svenja , Wyschkon Anne , Poltz Nadine , Kohn Juliane , Kucian Karin , von Aster Michael , Esser Günter
Published: May 2018

Zusammenfassung. Fragestellung: Ziel der Studie war die Überprüfung der Wirksamkeit einer vorschulischen Förderung des Mengen- und Zahlenverständnisses bei Kindern mit einem Risiko für die Entwicklung einer Rechenstörung unter Bedingungen, die sich am Alltag der Kindertagesstätten orientierten und somit auch bei einem breiten Einsatz einer Förderung eine relativ ökonomische Variante darstellen. Methodik: Die Risikokinder der Trainingsgruppe ( n = 20) wurden mit einer Kombination aus Mathematik im Vorschulalter ( Rademacher et al., 2009 ) und Mengen, zählen, Zahlen (Krajweski et al., 2007) von Erzieherinnen gefördert. Sie wurden einer nicht-geförderten Risiko-Kontrollgruppe ( n = 29) hinsichtlich ihrer Rechenleistungen sowie der Häufigkeit von Rechenschwächen bis zur 3. Klasse gegenübergestellt. Ergebnisse: In der 1. Klasse wiesen die trainierten Risikokinder Rechenleistungen im durchschnittlichen Bereich auf; die Kinder der Kontrollgruppe lagen im unterdurchschnittlichen Bereich. In der 2. und 3. Klasse konnte dieser Leistungsvorteil der Trainingsgruppe statistisch abgesichert werden. Die vorschulische Förderung reduzierte zudem das Risiko, eine Rechenschwäche auszubilden bis in die 3. Klasse. Schlussfolgerung: Eine Förderung mathematischer Basiskompetenzen unter ökonomischen Bedingungen in der Kita führt bei Risikokindern zu einer Verbesserung der späteren Rechenleistungen und reduziert die Auftretenswahrscheinlichkeit einer Rechenschwäche.
The Role of Historical Context in Understanding Past Climate, Pollution and Health Data in Trans‐disciplinary Studies: Reply to Comments on More et al., 2017
Authors: More Alexander F. , Spaulding Nicole E. , Bohleber Pascal , Handley Michael J. , Hoffmann Helene , Korotkikh Elena V. , Kurbatov Andrei V. , Loveluck Christopher P. , Sneed Sharon B. , McCormick Michael , Mayewski Paul A.
Published: May 2018

Understanding the context from which evidence emerges is of paramount importance in reaching robust conclusions in scientific inquiries. This is as true of the present as it is of the past. In a trans‐disciplinary study such as More et al. (2017, https://doi.org/10.1002/2017GH000064) and many others appearing in this and similar journals, a proper analysis of context demands the use of historical evidence. This includes demographic, epidemiological, and socio‐economic data—common in many studies of the impact of anthropogenic pollution on human health—and, as in this specific case, also geoarchaeological evidence. These records anchor climate and pollution data in the geographic and human circumstances of history, without which we lose a fundamental understanding of the data itself. This article addresses Hinkley (2018, https://doi.org/10.1002/2018GH000105) by highlighting the importance of context, focusing on the historical and archaeological evidence, and then discussing atmospheric deposition and circulation in the specific region of our study. Since many of the assertions in Bindler (2018, https://doi.org/10.1002/2018GH000135) are congruent with our findings and directly contradict Hinkley (2018), this reply refers to Bindler (2018), whenever appropriate, and indicates where our evidence diverges.
Study on the Curvature and Gradient of the Magnetic Field in Earth's Cusp Region Based on the Magnetic Curvature Analysis Method
Authors: Xiao Chao , Liu Wenlong , Shen Chao , Zhang Hua , Rong Zhaojin
Published: May 2018

This paper uses the multiple‐point magnetic measurements from the Cluster mission to investigate the curvature and gradient of the magnetic field as well as their relations with the current density inside the cusp region under different interplanetary magnetic field (IMF) conditions. From two event studies, it is shown that the curvature radius of magnetic field line is on average 5.13 RE under southward IMF and 19.75 RE under northward IMF condition. The directional angle of curvature is more distributed in a wider range under southward condition. The gradient of the magnetic field strength B is larger with a larger standard deviation under southward IMF condition. These results imply that the cusp region has more complicated magnetic structures under southward IMF condition. Through the correlation analysis between the magnetic field parameters and the current density, it is found that the magnetic gradient has a strong relation with total current density jt and perpendicular current density j⊥ when the ratio of parallel component j// to jt decreases, possibly due to gradient B drift. Furthermore, we present a statistical study on the 19 cusp crossing events from July 2003 to September 2003. The results from the statistical study are consistent with the event studies.
An Evolutive Linear Kinematic Source Inversion
Authors: Sánchez‐Reyes H. S. , Tago J. , Métivier L. , Cruz‐Atienza V. M. , Virieux J.
Published: May 2018

We present a new hierarchical time kinematic source inversion method able to assimilate data traces through evolutive time windows. A linear time domain formulation relates the slip rate function and seismograms, preserving the positivity of this function and the causality when spanning the model space: taking benefit of the time‐space sparsity of the rupture model evolution is as essential as considering the causality between rupture and each record delayed by the known propagator operator different for each station. This progressive approach, both on the data space and on the model space, does require mild assumptions on prior slip rate functions or preconditioning strategies on the slip rate local gradient estimations. These assumptions are based on simple physical expected rupture models we foresee. Successful applications of this method to a well‐known benchmark (Source Inversion Validation Exercise 1) and to the recorded data of the 2016 Kumamoto mainshock (Mw=7.0) illustrate the advantages of this alternative approach of a linear kinematic source inversion. This stabilized overparameterized optimization of a linear forward problem has a potential extension to stochastic inversion in a Bayesian framework in the future to assess uncertainties on kinematic source inversions, which is more difficult to investigate under nonlinear formulations.
Process‐Specific Contributions to Anomalous Java Mixed Layer Cooling During Positive IOD Events
Authors: Delman Andrew S. , McClean Julie L. , Sprintall Janet , Talley Lynne D. , Bryan Frank O.
Published: May 2018

Negative sea surface temperature (SST) anomalies associated with positive Indian Ocean Dipole (pIOD) events first appear in the seasonal upwelling zone along the southern coast of Java during May–July. The evolution of anomalous SSTs in this coastal region is analyzed by computing a temperature budget using output from a strongly eddy‐active ocean general circulation model. The seasonal cooling south of Java in May–July is driven by a reduction in incoming shortwave radiation and by vertical mixing, consistent with earlier studies in the region; however, the model budget also shows an advective contribution that drives anomalous cooling at the onset of pIOD events. To identify which process(es) are responsible for the anomalous advective cooling during pIOD events, a novel process index regression method is used to estimate the contributions of wind stress, equatorial Kelvin waves, mesoscale eddies, and Lombok Strait flow to anomalous cooling south of Java. Using this method, wind stress forcing along the west coast of Sumatra is found to make the most substantial contribution to anomalous cooling south of Java, with lesser contributions from equatorially sourced Kelvin waves and local wind stress. Mesoscale eddies redistribute heat from the Lombok Strait outflow, and have an anomalous warming effect on the eastern side of the upwelling region. The process‐specific temperature budget south of Java highlights the importance of wind stress forcing west of Sumatra relative to equatorial and local forcing, and explains most of the mixed layer temperature anomaly evolution associated with advection during pIOD events.
Variability of Surface Heat Fluxes and Its Driving Forces at Different Time Scales Over a Large Ephemeral Lake in China
Authors: Zhao Xiaosong , Liu Yuanbo
Published: May 2018

Poyang Lake is the largest freshwater lake in China. It is considered as an ephemeral lake—experiencing dynamic seasonal transitions ranging from a lake surface to wetland conditions. The influence of the seasonal water level transition on lake‐atmosphere energy exchange can have important consequences for local climate and water resource management. Here we study the dynamics of surface‐atmosphere energy exchange and examine the hydrological and meteorological controls on its partitioning for the period August 2013 to July 2016. Change in the water depth (WD) directly impacts water surface contribution and the inundated duration. The latent heat (LE) and sensible heat (H) fluxes showed an unimodal diurnal pattern in the wetland‐covered period and changed to an irregular pattern during the lake‐covered period when water surface contribution exceeded a value of 62%. The Bowen ratio (H/LE) was large/small in the wetland‐/lake‐covered period and decreased significantly with increasing WD. On a diurnal and daily timescale, the LE and H showed less dependence on wind speed (U) and water vapor or temperature gradient and greater dependence on net radiation when transitioning from the lake‐covered period to wetland‐covered period, respectively. On a monthly timescale, both the LE and H were mainly controlled by the net radiation. However, the interannual variations in LE and H were significantly correlated with the inundated duration and WD over Poyang Lake. The decreasing trend in Poyang Lake level, therefore, has potential to reduce lake evaporation and local precipitation and further amplify regional hydrometeorological droughts.
A Multigrid Nonlinear Least Squares Four‐Dimensional Variational Data Assimilation Scheme With the Advanced Research Weather Research and Forecasting Model
Authors: Zhang Hongqin , Tian Xiangjun
Published: May 2018

The motions of the atmosphere have multiscale properties in space and/or time, and the background error covariance matrix (Β) should thus contain error information at different correlation scales. To obtain an optimal analysis, the multigrid three‐dimensional variational data assimilation scheme is used widely when sequentially correcting errors from large to small scales. However, introduction of the multigrid technique into four‐dimensional variational data assimilation is not easy due to its strong dependence on the adjoint model, which has high computational costs in data coding, maintenance, and updating, especially for large‐scale, complex problems. In this study, the multigrid technique was introduced into the nonlinear least squares four‐dimensional variational assimilation (NLS‐4DVar) method, which is an advanced four‐dimensional ensemble‐variational method that can be applied without invoking the adjoint models. The multigrid NLS‐4DVar (MG‐NLS‐4DVar) scheme uses the number of grid points to control the scale, with doubling of this number when moving from coarser to finer grid levels. Furthermore, the MG‐NLS‐4DVar scheme not only retains the advantages of NLS‐4DVar but also sufficiently corrects multiscale errors to achieve a highly accurate analysis. The effectiveness and efficiency of the proposed MG‐NLS‐4DVar scheme were evaluated by one group of single‐observation experiments and one group of comprehensive evaluation experiments using the Advanced Research Weather Research and Forecasting Model. MG‐NLS‐4DVar outperformed NLS‐4DVar, with a lower computational cost.
Intercomparison Between VIIRS and CrIS by Taking Into Account the CrIS Subpixel Cloudiness and Viewing Geometry
Authors: Gong Xinya , Li Zhenglong , Li Jun , Moeller Christopher C. , Cao Changyong , Wang Wenhui , Menzel W. Paul
Published: May 2018

The Cross‐track Infrared Sounder (CrIS) onboard the Suomi National Polar‐orbiting Partnership (SNPP) has high radiometric accuracy, which can be used to intercompare and understand the radiometric performance of the thermal emissive bands of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the same platform. Previous studies usually selected uniform scenes to avoid potential uncertainties due to geolocation errors. This study focuses on all scenes (including nonuniform scenes), as well as CrIS subpixel cloudiness, local zenith angle and surface type, and their impacts on VIIRS/CrIS intercomparisons. A geolocation error correction scheme is applied to mitigate the geolocation mismatch between CrIS and VIIRS. Intercomparison results of three days from 19 to 21 September 2016, a quarterly warm up/cool down calibration period, show overall good agreement in terms of radiance biases (less than 0.2 K in terms of brightness temperature) between VIIRS and CrIS, for scene temperatures between 220 and 300 K; however, larger biases are evident outside of this range. The three factors—CrIS subpixel cloudiness, local zenith angle, and surface type—show weak impacts on VIIRS radiance biases. Both clear‐sky and overcast conditions have slightly different radiance biases from other partially cloudy conditions because of more contributions from colder or warmer scenes. The time series show the impact of warm up/cool down and the effectiveness of the correction algorithm for reprocessing VIIRS M15 and M16 data sets. The methods and tools can be applied to monitor and validate other infrared imager/sounder duos onboard the same platform.
A Statistical Study of Inertia Gravity Waves in the Lower Stratosphere Over the Arctic Region Based on Radiosonde Observations
Authors: Huang Kai Ming , Yang Zun Xun , Wang Rui , Zhang Shao Dong , Huang Chun Ming , Yi Fan , Hu Fei
Published: May 2018

Relative to many investigations of inertial gravity waves (IGWs) in the Antarctic, IGW activity in the Arctic region was paid less attention to. We use radiosonde observations at the Ny‐Alesund station (78.9°N, 11.9°E) from April 2012 to June 2016 to study the IGW characteristics in the lower stratosphere over the Arctic. The observation reveals a prevailing eastward zonal background wind below 20 km and an obvious annual cycle of the background temperature from the troposphere to the lower stratosphere, which is different from the results in the middle and low latitudes. By combining Lomb‐Scargle spectrum and hodograph technique, case study demonstrates that the lower stratospheric IGWs exhibit a feature of freely propagating waves. Statistical analysis indicates that the IGWs have dominant horizontal (vertical) wavelength of 50–1,050 km (1–4 km) and ratio (1–2.5) of the intrinsic to inertia frequencies. Wave energy exhibits an annual oscillation with the maximum in winter and the minimum in summer. In winter, the downward propagating waves increase to about 20% due to polar stratospheric vortex. Because of the lower atmospheric filtering, the IGWs display a dominant direction of westward propagation, thus have a mean vertical flux of −0.647 mPa for the zonal momentum, which indicates that the IGWs can put a westward drag on the atmospheric wind field over the Arctic as they break and dissipate. All the vertical wavenumber spectra have spectral slopes from −2.23 to −2.99 close to the universal spectrum index of −3.
Attributing the Carbon Cycle Impacts of CMIP5 Historical and Future Land Use and Land Cover Change in the Community Earth System Model (CESM1)
Authors: Lawrence Peter J. , Lawrence David M. , Hurtt George C.
Published: May 2018

Historical global land use and land cover change (LULCC) emissions of 160 PgC represent a third of all human CO2 emissions from 1850 to 2010. Future land management decisions will have large impacts on the global carbon cycle, with scenarios ranging from continued deforestation and wood harvest to mitigation scenarios that reduce total emissions through afforestation and conversion to bioenergy. Here we present a systematic assessment of Community Earth System Model (CESM1) Coupled Model Intercomparison Project phase 5 (CMIP5) historic and projection simulations, with and without LULCC. For the historical period, CESM produced a Net LULCC flux of 123 PgC to the atmosphere, removing −130 PgC from ecosystems while increasing wood product pools by 7 PgC. Historical LULCC fluxes were equally divided between conversion and wood harvest fluxes. For the Representative Concentration Pathway (RCP) 4.5 afforestation scenario CESM produced a Net LULCC flux of 53 PgC to the atmosphere, removing −58 PgC out of the ecosystem and increasing wood product pools of 5 PgC. The afforestation offsets the Direct LULCC flux of 153 PgC with a negative Indirect LULCC flux of −94 PgC. For the RCP 8.5 high LULCC scenario, CESM produced a Net LULCC flux of 211 PgC, removing −227 PgC from ecosystems and increasing wood product pools of 15 PgC. The LULCC of the future RCP scenarios was dominated by wood harvest fluxes, which is a process that was not included in many of the CMIP5 models. The analysis framework also allowed the attribution of Indirect and Prior LULCC fluxes that offset the Direct LULCC fluxes in many cases.
Threshold Effects for the Decrepitation and Stretching of Fluid Inclusions
Authors: Campione M.
Published: May 2018

Minerals embedding fluids in the form of microinclusions are recurrent in xenoliths and exploited for inferring the characteristics of magma dynamics in relation to volcanism. Xenolith migration from mantle conditions to Earth surface might trigger failure transformations known as decrepitation and stretching. The former is a fairly recognizable transformation, corresponding to the brittle failure of the host mineral nearby the inclusion. The latter is a more intriguing transformation, corresponding to the plastic expansion of the cavity, that is, without fracture formation. Both transformations bring about a decrease of the fluid inclusion density, preventing to assess the original depth level of the xenolith. Here decrepitation and stretching are analyzed in the framework of an elastic‐plastic model providing a thorough tool to interpret experimental density data. Both phenomena are shown to be governed by threshold effects, establishing a net boundary between preserved and failed matrixes in terms of cavity size, internal, and confining pressure. A common feature of stretched systems emerges in the concept of the limiting pressure, influencing the maximum value of the inclusion pressure one might expect for a specific matrix, and the inferred depth of magma storage levels.
Ultrahigh-resolution nonlinear optical imaging of the armchair orientation in 2D transition metal dichalcogenides
Authors: Psilodimitrakopoulos Sotiris , Mouchliadis Leonidas , Paradisanos Ioannis , Lemonis Andreas , Kioseoglou George , Stratakis Emmanuel
Published: May 2018

We used nonlinear laser scanning optical microscopy to study atomically thin transition metal dichalcogenides (TMDs) and revealed, with unprecedented resolution, the orientational distribution of armchair directions and their degree of organization in the two-dimensional (2D) crystal lattice. In particular, we carried out polarization-resolved second-harmonic generation (PSHG) imaging for monolayer WS2 and obtained, with high-precision, the orientation of the main crystallographic axis (armchair orientation) for each individual 120 × 120 nm2 pixel of the 2D crystal area. Such nanoscale resolution was realized by fitting the experimental PSHG images, obtained with sub-micron precision, to a new generalized theoretical model that accounts for the nonlinear optical properties of TMDs. This enabled us to distinguish between different crystallographic domains, locate boundaries and reveal fine structure. As a consequence, we can calculate the mean orientational average of armchair angle distributions in specific regions of interest and define the corresponding standard deviation as a figure-of-merit for the 2D crystal quality.
Negative reflection and negative surface wave conversion from obliquely incident electromagnetic waves
Authors: Liu Shuo , Jun Cui Tie , Noor Ahsan , Tao Zui , Chi Zhang Hao , Dong Bai Guo , Yang Yan , Yang Zhou Xiao
Published: May 2018

Complete control of spatially propagating waves (PWs) and surface waves (SWs) is an ultimate goal that scientists and engineers seek for, in which negative reflection of PW and negative surface wave are two exotic phenomena. Here, we experimentally demonstrate an anisotropic digital coding metasurface capable of controlling both PWs and SWs with a single coding pattern. On the basis of the digital description of coding metasurfaces, a simple coding method is proposed to allow dual functionalities (either PW or SW manipulations) under two orthogonal polarizations at arbitrarily oblique incidences, thus improving the adaptability of digital coding metasurfaces in more practical circumstances. With elaborately designed ellipse-shaped coding particles, we experimentally demonstrate various functions under oblique incidences, including the negative reflection of PW, negative SW, anomalous reflection and their arbitrary combinations, all having good agreements with theoretical and numerical predictions. We believe that the proposed method may enable the digital coding metasurfaces to have broad applications in radar detections, wireless communications and imaging.
Entanglement beating in free space through spin–orbit coupling
Authors: Otte Eileen , Rosales-Guzmán Carmelo , Ndagano Bienvenu , Denz Cornelia , Forbes Andrew
Published: May 2018

It is well known that the entanglement of a quantum state is invariant under local unitary transformations. This rule dictates, for example, that the entanglement of internal degrees of freedom of a photon remains invariant during free-space propagation. Here, we outline a scenario in which this paradigm does not hold. Using local Bell states engineered from classical vector vortex beams with non-separable degrees of freedom, the so-called classically entangled states, we demonstrate that the entanglement evolves during propagation, oscillating between maximally entangled (purely vector) and product states (purely scalar). We outline the spin–orbit interaction behind these novel propagation dynamics and confirm the results experimentally, demonstrating spin–orbit coupling in paraxial beams. This demonstration highlights a hitherto unnoticed property of classical entanglement and simultaneously offers a device for the on-demand delivery of vector states to targets, for example, for dynamic laser materials processing, switchable resolution within stimulated emission depletion (STED) systems, and a tractor beam for entanglement.
Sheathless inertial cell focusing and sorting with serial reverse wavy channel structures
Authors: Zhou Yinning , Ma Zhichao , Ai Ye
Published: May 2018

Inertial microfluidics utilizing passive hydrodynamic forces has been attracting significant attention in the field of precise microscale manipulation owing to its low cost, simplicity and high throughput. In this paper, we present a novel channel design with a series of reverse wavy channel structures for sheathless inertial particle focusing and cell sorting. A single wavy channel unit consists of four semicircular segments, which produce periodically reversed Dean secondary flow along the cross-section of the channel. The balance between the inertial lift force and the Dean drag force results in deterministic equilibrium focusing positions, which also depends on the size of the flow-through particles and cells. Six sizes of fluorescent microspheres (15, 10, 7, 5, 3 and 1 μm) were used to study the size-dependent inertial focusing behavior. Our novel design with sharp-turning subunits could effectively focus particles as small as 3 μm, the average size of platelets, enabling the sorting of cancer cells from whole blood without the use of sheath flows. Utilizing an optimized channel design, we demonstrated the size-based sorting of MCF-7 breast cancer cells spiked in diluted whole blood samples without using sheath flows. A single sorting process was able to recover 89.72% of MCF-7 cells from the original mixture and enrich MCF-7 cells from an original purity of 5.3% to 68.9% with excellent cell viability.
CARF enrichment promotes epithelial–mesenchymal transition via Wnt/β-catenin signaling: its clinical relevance and potential as a therapeutic target
Authors: Kalra Rajkumar S. , Chaudhary Anupama , Yoon A-Rum , Bhargava Priyanshu , Omar Amr , Garg Sukant , Yun Chae-Ok , Kaul Sunil C. , Wadhwa Renu
Published: May 2018

CARF (Collaborator of ARF)/CDKN2AIP was discovered as a novel ARF-binding protein. It has been established as an essential cell survival, p53-, and cell proliferation-regulatory protein. Although a moderate upregulation of CARF caused growth arrest and senescence, its excessively enriched levels were shown to facilitate aggressive proliferation and malignant transformation of cancer cells. Here, we examined the relevance of CARF levels in clinical tumors and found its amplification (both at gene and transcript levels) in a variety of invasive and metastatic malignancies. Consistent with the clinical readouts, enrichment of CARF in cancer cells promoted epithelial–mesenchymal transition (EMT). Cancer database and molecular analyses revealed that it activates Wnt/β-catenin signaling axis, as evident by enhanced nuclear localization and function of β-catenin marked by increased level of SNAIL1, SNAIL2, ZEB1, and TWIST1 and its downstream gene targets. Of note, targeted knockdown of CARF led to decrease in nuclear β-catenin and its key downstream effectors, involved in EMT progression. Consistent with this, CARF targeting in vivo either by naked siRNA or CARF shRNA harboring adeno-oncolytic virus caused suppression of tumor progression and lung metastasis. Taken together, we report clinical and therapeutic relevance of CARF in EMT and cancer invasiveness/metastasis, and propose it as a potent therapeutic target of aggressive cancers.
Semaphorin 4D correlates with increased bone resorption, hypercalcemia, and disease stage in newly diagnosed patients with multiple myeloma
Authors: Terpos Evangelos , Ntanasis-Stathopoulos Ioannis , Christoulas Dimitrios , Bagratuni Tina , Bakogeorgos Marios , Gavriatopoulou Maria , Eleutherakis-Papaiakovou Evangelos , Kanellias Nikolaos , Kastritis Efstathios , Dimopoulos Meletios A.
Published: May 2018

Multiple myeloma (MM) is characterized by bone destruction due to increased bone resorption and decreased bone formation. Semaphorin 4D (CD100, Sema4D) is expressed by osteoclasts, binds to its receptor Plexin-B1, and acts as a mediator of osteoclast–osteoblast interaction that ultimately inhibits osteoblastic bone formation. Preclinical data suggest that Sema4D/Plexin-B1 pathway is implicated in MM-induced bone disease. However, there is no information on the role of Sema4D in MM patients. Thus, we evaluated Sema4D and Plexin-B1 in six myeloma cells lines in vitro; in the bone marrow plasma (BMP) and serum of 72 newly diagnosed symptomatic MM (NDMM) patients and in 25 healthy controls. Only one myeloma cell line produced high Sema4D. BMP and circulating Sema4D and Plexin-B1 levels were significantly higher in MM patients compared to controls (p < 0.01). Sema4D correlated with serum calcium levels (p < 0.001), increased bone resorption (as assessed by CTX; p < 0.01), and ISS (p < 0.001). There was a trend for higher Sema4D levels in patients with osteolysis (p = 0.07), while patients with diffuse MRI pattern had higher BMP Sema4D levels (p = 0.02). Our data suggest that Sema4D is elevated in MM patients and correlate with adverse myeloma features and increased bone resorption, providing a possible target for novel therapeutic approaches in MM.
Genome-wide and high-density CRISPR-Cas9 screens identify point mutations in PARP1 causing PARP inhibitor resistance
Authors: Pettitt Stephen J. , Krastev Dragomir B. , Brandsma Inger , Dréan Amy , Song Feifei , Aleksandrov Radoslav , Harrell Maria I. , Menon Malini , Brough Rachel , Campbell James , Frankum Jessica , Ranes Michael , Pemberton Helen N. , Rafiq Rumana , Fenwick Kerry , Swain Amanda , Guettler Sebastian , Lee Jung-Min , Swisher Elizabeth M. , Stoynov Stoyno , Yusa Kosuke , Ashworth Alan , Lord Christopher J.
Published: May 2018

Although PARP inhibitors (PARPi) target homologous recombination defective tumours, drug resistance frequently emerges, often via poorly understood mechanisms. Here, using genome-wide and high-density CRISPR-Cas9 “tag-mutate-enrich” mutagenesis screens, we identify close to full-length mutant forms of PARP1 that cause in vitro and in vivo PARPi resistance. Mutations both within and outside of the PARP1 DNA-binding zinc-finger domains cause PARPi resistance and alter PARP1 trapping, as does a PARP1 mutation found in a clinical case of PARPi resistance. This reinforces the importance of trapped PARP1 as a cytotoxic DNA lesion and suggests that PARP1 intramolecular interactions might influence PARPi-mediated cytotoxicity. PARP1 mutations are also tolerated in cells with a pathogenic BRCA1 mutation where they result in distinct sensitivities to chemotherapeutic drugs compared to other mechanisms of PARPi resistance (BRCA1 reversion, 53BP1, REV7 (MAD2L2) mutation), suggesting that the underlying mechanism of PARPi resistance that emerges could influence the success of subsequent therapies.
TGF-β induces miR-100 and miR-125b but blocks let-7a through LIN28B controlling PDAC progression
Authors: Ottaviani Silvia , Stebbing Justin , Frampton Adam E. , Zagorac Sladjana , Krell Jonathan , de Giorgio Alexander , Trabulo Sara M. , Nguyen Van T. M. , Magnani Luca , Feng Hugang , Giovannetti Elisa , Funel Niccola , Gress Thomas M. , Jiao Long R. , Lombardo Ylenia , Lemoine Nicholas R. , Heeschen Christopher , Castellano Leandro
Published: May 2018

TGF-β/Activin induces epithelial-to-mesenchymal transition and stemness in pancreatic ductal adenocarcinoma (PDAC). However, the microRNAs (miRNAs) regulated during this response have remained yet undetermined. Here, we show that TGF-β transcriptionally induces MIR100HG lncRNA, containing miR-100, miR-125b and let-7a in its intron, via SMAD2/3. Interestingly, we find that although the pro-tumourigenic miR-100 and miR-125b accordingly increase, the amount of anti-tumourigenic let-7a is unchanged, as TGF-β also induces LIN28B inhibiting its maturation. Notably, we demonstrate that inactivation of miR-125b or miR-100 affects the TGF-β-mediated response indicating that these miRNAs are important TGF-β effectors. We integrate AGO2-RIP-seq with RNA-seq to identify the global regulation exerted by these miRNAs in PDAC cells. Transcripts targeted by miR-125b and miR-100 significantly overlap and mainly inhibit p53 and cell–cell junctions’ pathways. Together, we uncover that TGF-β induces an lncRNA, whose encoded miRNAs, miR-100, let-7a and miR-125b play opposing roles in controlling PDAC tumourigenesis.
Chiral Landau levels in Weyl semimetal NbAs with multiple topological carriers
Authors: Yuan Xiang , Yan Zhongbo , Song Chaoyu , Zhang Mengyao , Li Zhilin , Zhang Cheng , Liu Yanwen , Wang Weiyi , Zhao Minhao , Lin Zehao , Xie Tian , Ludwig Jonathan , Jiang Yuxuan , Zhang Xiaoxing , Shang Cui , Ye Zefang , Wang Jiaxiang , Chen Feng , Xia Zhengcai , Smirnov Dmitry , Chen Xiaolong , Wang Zhong , Yan Hugen , Xiu Faxian
Published: May 2018

Recently, Weyl semimetals have been experimentally discovered in both inversion-symmetry-breaking and time-reversal-symmetry-breaking crystals. The non-trivial topology in Weyl semimetals can manifest itself with exotic phenomena, which have been extensively investigated by photoemission and transport measurements. Despite the numerous experimental efforts on Fermi arcs and chiral anomaly, the existence of unconventional zeroth Landau levels, as a unique hallmark of Weyl fermions, which is highly related to chiral anomaly, remains elusive owing to the stringent experimental requirements. Here, we report the magneto-optical study of Landau quantization in Weyl semimetal NbAs. High magnetic fields drive the system toward the quantum limit, which leads to the observation of zeroth chiral Landau levels in two inequivalent Weyl nodes. As compared to other Landau levels, the zeroth chiral Landau level exhibits a distinct linear dispersion in magnetic field direction and allows the optical transitions without the limitation of zero z momentum or $$\sqrt B$$

B

magnetic field evolution. The magnetic field dependence of the zeroth Landau levels further verifies the predicted particle-hole asymmetry of the Weyl cones. Meanwhile, the optical transitions from the normal Landau levels exhibit the coexistence of multiple carriers including an unexpected massive Dirac fermion, pointing to a more complex topological nature in inversion-symmetry-breaking Weyl semimetals. Our results provide insights into the Landau quantization of Weyl fermions and demonstrate an effective tool for studying complex topological systems.
Explaining the apparent impenetrable barrier to ultra-relativistic electrons in the outer Van Allen belt
Authors: Ozeke Louis G. , Mann Ian R. , Murphy Kyle R. , Degeling Alex W. , Claudepierre Seth G. , Spence Harlan E.
Published: May 2018

Recent observations have shown the existence of an apparent impenetrable barrier at the inner edge of the ultra-relativistic outer electron radiation belt. This apparent impenetrable barrier has not been explained. However, recent studies have suggested that fast loss, such as associated with scattering into the atmosphere from man-made very-low frequency transmissions, is required to limit the Earthward extent of the belt. Here we show that the steep flux gradient at the implied barrier location is instead explained as a natural consequence of ultra-low frequency wave radial diffusion. Contrary to earlier claims, sharp boundaries in fast loss processes at the barrier are not needed. Moreover, we show that penetration to the barrier can occur on the timescale of days rather than years as previously reported, with the Earthward extent of the belt being limited by the finite duration of strong solar wind driving, which can encompass only a single geomagnetic storm.
Author Correction: A proteomic landscape of diffuse-type gastric cancer
Authors: Ge Sai , Xia Xia , Ding Chen , Zhen Bei , Zhou Quan , Feng Jinwen , Yuan Jiajia , Chen Rui , Li Yumei , Ge Zhongqi , Ji Jiafu , Zhang Lianhai , Wang Jiayuan , Li Zhongwu , Lai Yumei , Hu Ying , Li Yanyan , Li Yilin , Gao Jing , Chen Lin , Xu Jianming , Zhang Chunchao , Jung Sung Yun , Choi Jong Min , Jain Antrix , Liu Mingwei , Song Lei , Liu Wanlin , Guo Gaigai , Gong Tongqing , Huang Yin , Qiu Yang , Huang Wenwen , Shi Tieliu , Zhu Weimin , Wang Yi , He Fuchu , Shen Lin , Qin Jun
Published: May 2018

The original version of this Article contained an error in the email address of the corresponding author Jun Qin. The correct email is jqin1965@126.com. The error has been corrected in the HTML and PDF versions of the Article.