bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell Morphologies and Contacts in Annual Fish Embryos
Authors: Lesseps Roland
Published: June 2020

During epiboly and early dispersed stages, the deep blastomeres of
annual fish embryos emigrate from the blastodisc to wander as easily visible
single cells in the narrow space between the yolk synctial layer (YSL) and
the enveloping cell layer (ECL). Subsequently these deep blastomeres
reaggregate and eventually form the definitive embryo. We are studying these
morphogen-etic cell movements and the controls that may exist upon cell
movement in vivo. Time-lapse cinemicrophotography showed three types of cell
movement by the deep blastomeres during epiboly through reaggregation stages
[1], The present electron microscopic investigation was undertaken to reveal
further details of the intercellular contacts during these developmental
stages.
Ultrastructural and Scanning Electron Microscopic Studies of Basal Cell
Carcinoma
Authors: Lupulescu A.
Published: June 2020

Previously it has been shown that long-term topical application of
3-methylcholanthrene (MCA) on the rat skin induced basal cell carcinoma.
These tumors are very similar to that occurring in humans and they were
studied only by light microscopy.1 Transmission electron microscopy (TEM)
and Scanning electron microscopy (SEM) can provide more characteristic
details for the neoplastic transformation of basal cells, their
cytoarchitecture and migration.
Distribution and Movement of Anionic Cell Surface Sites in Dissociated
Neoplastic Pancreatic Acinar Cells
Authors: Minick O. T. , Qureshi S. A. , Reddy J. K.
Published: June 2020

The establishment recently of a transplantable pancreatic acinar
carcinoma of rat in our laboratory1, provides a
suitable model system to analyze morphogenetic, enzymic and functional
differentiation in transformed secretory epithelial cells. Morphologic
analysis of this tumor has revealed a continuum of neoplastic cells from
those which totally lack mature secretory granules to cells with abundant,
well-formed secretory granules. This tumor is easily dissociable into single
cells and these cells are found to be more susceptible to agglutination by
concanavalin A than the normal pancreatic acinar
cells2.
Advantages and Limitations of A Simple Cold Block Freeze-Fracture
Technique
Authors: Bullivant S.
Published: June 2020

The simple cold block freeze-fracture technique1
was introduced by Bullivant and Ames in 1966.5 There
are three major differences between this technique and other
freeze-fracture/etch techniques. These are firstly that etching is generally
not performed, as the specimen is at about -14°C when shadowed; secondly
that the frozen specimen is fractured under the surface of liquid nitrogen
rather than cut with a cold microtome under vacuum; and thirdly that it is
then transferred enclosed within the interior of a nesting metal block
system at liquid nitrogen temperature to the vacuum evaporator, where it
remains effectively shielded from contamination until replication is carried
out by shadowing through narrow tunnels in the block. Since 1966 we have
evaluated this simple freeze-fracture technique quite thoroughly and in this
review I will detail those areas in which I think the results obtained are
equal to or better than those obtained with the more complicated and
expensive freeze-etch machines, and also those areas in which the simple
method has limitations.
Effect of Integral Proteins on Frozen Membrane Fracture
Authors: Kirchanski S. , Branton D.
Published: June 2020

We have investigated the effect of integral membrane proteins upon the
fracturing of frozen lipid bilayers. This investigation has been part of an
effort to develop freeze fracture labeling techniques and to assess the
possible breakage of covalent protein bonds during the freeze fracture
process. We have developed an experimental protocol utilizing lectin
affinity columns which should detect small amounts of covalent bond breakage
during the fracture of liposomes containing purified (1) glycophorin (a
transmembrane glycoprotein of human erythrocyte membranes). To fracture
liposomes in bulk, frozen liposomes are ground repeatedly under liquid
nitrogen. Failure to detect any significant covalent bond breakage (contrary
to (2)) led us to question the effectiveness of our grinding procedure in
fracturing and splitting lipid bilayers.
Ciliogenesis of The Retinal Photoreceptor
Authors: Greinert Jack V. , Daniel Bodley H. , Weidman Thomas A.
Published: June 2020

Development of the modified cilium in rod photoreceptors is unique in
that, unlike other ciliated epithelia, the photoreceptor cilium does not
project into a free lumen but rather abuts against the apex of another
epithelial cell, i.e. pigmented epithelium. Development of the modified
cilium in rod photoreceptors of the ferret retina involves a temporary
invagination of the plasma membrane encircling the base of each developing
cilium. This study proposes a mechanism that would account for this apical
invagination into which the connecting cilium develops.
A Preliminary Fine Structural Analysis of Cell:Cell and Cell:Substrate
Adhesion in C4I
Authors: Dembitzer H. M. , Schermer A. , Herz F. , Koss L.G.
Published: June 2020

C4I is a desmosome-forming cell line derived from a human cervical
carcinoma (1). During the course of a study of desmosome formation in this
line (2) it was found that a solution of 0.05% trypsin-0.02% EDTA dispersed
monolayers of these cells into a suspension composed of over 90% single
cells. Trypsin alone, however, even at a concentration of 0.25% did not
disperse C4I monolayers into single cells. In order to gain an understanding
of some of the factors responsible for holding C4I cells together and for
their adhesion to the growth surface, a fine structural study of the action
of the various dispersants, either singly or in combination, was
undertaken.
Effect of Epidermal Growth Factor on Adult Rat Hepatocyte Monolayer
Cultures
Authors: Samsonoff W. A. , Jansing R.
Published: June 2020

Primary hepatocyte monolayer cultures have proven useful for in vitro
study of parenchymal cell function. Unfortunately these cultures lose liver
function rapidly and are often short-lived. Modified subtrates (1,2) can
overcome some of these problems, but they produce fewer viable cells.
Specific media supplements can also prolong cellular function. Epidermal
growth factor (EGF) for example, significantly affects the structure and
function of cells in culture (3). In this study we determined the effect of
EGF on the ultrastructure and function of hepatocytes from Fisher 344 adult
male rats. They were maintained as primary monolayer cultures in Leibovitz
L-15 medium with supplements.
Calibration of Sem Frozen-Hydrated Analyses Using Standard Salt Solutions
and Peak to Background Measurements
Authors: Lai C. E. , Hayes T. L.
Published: June 2020

The analysis of frozen hydrated samples by SEM/EDX provides elemental
and morphologic information about the specimen without requiring any
preparative drying process. The problem of spatial translocation of elements
associated with dehydration is considerably reduced. Echlin (1979 and 1980),
has conducted qualitative experiments on Lemna minor root determining the
changes in elemental composition of differentiating meristematic tissue.
This study shows that it is feasible, using the peak to local background
ratio technique, to semi-quantitate elemental compositions in frozen
hydrated salt solutions that may be useful as calibration
standards.
Attachment of Tonofilaments to the Nuclear Membrane Demonstrated by HVEM
Stereoscopy
Authors: Parsons D. F. , Marko M.
Published: June 2020

We have used thick section HVEM stereoscopy at multiple double-tilt
angles to follow the course of long segments of tonofilament bundles in the
squamous cells of human oral-cavity carcinoma and normal human skin. This
approach serves to supplement and confirm the general distribution of the
tonofilament network of whole cells indicated by light microscope
immunofluorescent staining using specific keratin
antibodies1. However, the HVEM approach has several
advantages; (1) the drastic specimen preparation methods required in LM
immunofluorescence to admit the antibody label into the cells can be
avoided, (2) details of individual tonofilament attachment can be observed
(3) the thick sections give better sampling of fine detail than can be
obtained with conventional EM thin sections. Our initial thin section work
gave no suggestion of attachment of tonofilaments to the nuclear membrane
but this was frequently seen in the thick sections. On returning to the thin
sections the probable attachments could be found. However, the absence of a
3-D view in the thin sections did not allow filament termination to be
distinguished from grazing contact of filaments with the membrane. Finally,
(4), the HVEM conveniently allows comparison of thick section results with
critical-point-dried whole cells either prepared as for LM
immunofluorescence or for HVEM.
Studies on The Cytoplasmic Ground Substance Using High Voltage Electron
Microscopy of Whole Cultured Cells
Authors: Porter K.R. , Luby K.J.
Published: June 2020

Cells of several types, when grown and maintained in monolayer culture,
will spread on the substrate to be not greater than 1 pm thick in their
thinner margins. When fixed with glutaraldehyde and
OsO4 and then dried by the critical-point
method,these cells can be viewed in the HVEM and stereo images of very high
quality can be obtained. Grown directly on formvar-coated gold grids, such
cells are quickly and easily prepared for microscopy.
In Situ HVEM Deformation of Aluminum Alloys
Authors: Kenik E. A. , Carpenter R. W.
Published: June 2020

Deformation processes in a series of aluminum alloys have been
investigated by in situ tensile deformation in the ORNL high voltage
electron microscope (HVEM). Both solid-solution-hardened and
preoipitation-hardened alloys have been studied in several heat treatments.
Interactions of moving dislocations with other dislocations, precipitates,
grain boundaries, and other defects were investigated, as were the
microstructural processes involved in the ductile failure of such specimens.
Specimens of Al-4 wt % Cu and 1100 aluminum alloy were deformed at room
temperature in a Gatan tensile deformation stage.
Cultural roots of family ties
Authors: Davis Lewis S. , Williamson Claudia R.
Published: June 2020

We forward the hypothesis and empirically establish that variations in the strength of family ties are rooted in culture. In particular, we show that individualism is associated with looser family ties. We exploit the associations between contemporary individualism and historical climatic and disease environments to establish a causal relationship. At both the individual- and country-levels, we find strong support that individualism reduces family ties. The estimated effects are economically large and robust to a wide variety of potentially confounding variables.
Are Positive Interventions Always Beneficial?
Authors: Briñol Pablo , Petty Richard E. , Gandarillas Beatriz , Moreno Lorena
Published: June 2020

Can people improve their lives by smiling more, trying to have a better posture, and by thinking about good memories? Can individuals become more successful by deliberatively engaging in positive actions and thoughts? Do people feel better by following recommendations from naïve psychology? In the present article we discuss these questions, noting that although some popular interventions thought to be universally beneficial (e.g., inductions of happiness, self-affirmation, empowerment, self-distancing) can sometimes yield positive outcomes, at other times the outcomes can also be negative. Taking an empirical approach based on experimental evidence, we postulate that understanding the underlying processes discovered in the science of persuasion is the key for specifying why, when, and for whom these practical initiatives are more likely to work or to backfire.
Spanish Validation and Scoring of the Internet Gaming Disorder Scale - Short-Form (IGDS9-SF)
Authors: Sánchez-Iglesias Iván , Bernaldo-de-Quirós Mónica , Labrador Francisco J. , Estupiñá Puig Francisco J. , Labrador Marta , Fernández-Arias Ignacio
Published: June 2020

Since the inclusion of the Internet Gaming Disorder (IGD) in the Diagnostic and statistical manual of mental disorders (5th ed.) (DSM-5), the Internet Gaming Disorder Scale-Short Form (IGDS9-SF), a short nine items test, has become one of the most used standardized instruments for its psychometric evaluation. This study presents a validation and psychometric evaluation of the Spanish version of the IGDS9-SF. A sample of 2173 videogame players between 12 and 22 years old, comprising both genders, was employed, achieved with a randomized selection process from educational institutions in the city of Madrid. Participants completed the adapted version of the IGDS9-SF, the General Health Questionnaire (GHQ-12) and a negative cognitions scale associated with videogame use, as well as sociodemographic data and frequency of videogame play. A unifactorial structure with sufficient reliability and internal consistency was found through exploratory and confirmatory analyses. In addition, the instrument was found to have good construct validity; the scoring of the IGDS9-SF were found to show a positive association with gaming frequency, with general health problems, and to a greater extent, with problematic cognitions with regard to videogames. Factorial invariance was found concerning the age of participants. However, even though the factorial structure was consistent across genders, neither metric nor scalar invariance were found; for this reason, we present a scale for the whole sample and a different one for gender. These results suggest that this Spanish version of the IGDS9-SF is a reliable and valid instrument, useful to evaluate the severity of IGD in Spanish students, and we provide a scoring scale for measurement purposes.
Iliac vein stenting guided by intravascular ultrasound without	iodinated contrast medium
Authors: Wang Xiang , Yu Chong , Chen Guojun , Hong Yi , Zhou Bin , Ge Jin , Liu Tuoen
Published: June 2020

Summary: Iliac vein compression syndrome, also known as May-Thurner Syndrome, is a type of vein reflux disorders which is often ignored due to lack of efficient diagnostic methods. The traditional gold standard of diagnosis is venography, but this has been challenged and largely replaced by intravascular ultrasound (IVUS). Here we report a case that a patient suffered with iodine anaphylaxis was successfully performed iliac vein stenting guided by using IVUS alone. This case provides the evidence that IVUS can offer necessary information for physicians in the diagnosis and treatment of iliac vein compression. We also find that balloon dilatation notch cannot precisely reflect the whole lesion, indicating it may be unreliable for diagnosis. Differ from the commonly accepted opinion, we find that comparing to IVUS, the notch of balloon dilatation cannot completely reflect the extent of lesion narrowness. Thus, we think the notch should not be used as a reference for seriousness of the lesion, and the diagnosis of stenosis cannot be ruled out even if there is no presence of notch.
Evaluating the Ionospheric Mass Source for Jupiter's Magnetosphere: An Ionospheric Outflow Model for the Auroral Regions
Authors: Martin C. J. , Ray L. C. , Constable D. A. , Southwood D. J. , Lorch C. T. S. , Felici M.
Published: June 2020

Ionospheric outflow is the flow of plasma initiated by a loss of equilibrium along a magnetic field line, which induces an ambipolar electric field due to the separation of electrons and ions in a gravitational field and other mass‐dependent sources. We have developed an ionospheric outflow model using the transport equations to determine the number of particles that flow into the outer magnetosphere of Jupiter. The model ranges from 1,400 km in altitude above the 1 bar level to 2.5 RJ along the magnetic field line and considers H+ and
as the main ion constituents. Previously, only pressure gradients and gravitational forces were considered in modeling polar wind. However, at Jupiter we need to evaluate the effect of field‐aligned currents present in the auroral regions due to the breakdown of corotation in the magnetosphere, along with the centrifugal force exerted on the particles due to the fast planetary rotation rate. The total number flux from both hemispheres is found to be 1.3–1.8 × 1028 s−1 comparable in total number flux to the Io plasma source. The mass flux is lower due to the difference in ion species. This influx of protons from the ionosphere into the inner and middle magnetosphere needs to be included in future assessments of global flux tube dynamics and composition of the magnetosphere system.
The Effect of Field‐Aligned Currents and Centrifugal Forces on Ionospheric Outflow at Saturn
Authors: Martin C. J. , Ray L. C. , Felici M. , Constable D. A. , Lorch C. T. S. , Kinrade J. , Gray R. L.
Published: June 2020

Ionospheric outflow is driven by an ambipolar electric field induced due to the separation of electrons and ions in a gravitational field when equilibrium along a magnetic field line is lost. A model of ionospheric outflow at Saturn was developed using transport equations to estimate the number of charged particles that flow from the auroral regions into the magnetosphere. The model evaluates the outflow from 1,400 km in altitude above the 1 bar level, to 3 RS along the field line. The main ion constituents evaluated are R+ and
. We consider the centrifugal force exerted on the particles due to a fast rotation rate, along with the effects of field‐aligned currents present in the auroral regions. The total number flux from both auroral regions is found to be 5.5–13.0×1027 s−1, which relates to a total mass source of 5.5–17.7 kg s−1. These values are on average an order of magnitude higher than expected without the additional effects of centrifugal force and field‐aligned currents. We find the ionospheric outflow rate to be comparable to the lower estimates of the mass loading rate from Enceladus and are in agreement with recent Cassini observations. This additional mass flux into the magnetosphere can substantially affect the dynamics and composition of the inner and middle magnetosphere of Saturn.
Using the Sigma‐Pi Diagram to Analyze Water Masses in the Northern South China Sea in Spring
Authors: Gao Yang , Huang Rui Xin , Zhu Jia , Huang Yongxiang , Hu Jianyu
Published: June 2020

The temperature‐salinity (T‐S) diagram is widely used in water mass analysis, but the boundaries between water masses are vaguely distinguished by conventional T‐S‐based methods. Herein, we propose a new method based on the potential density‐potential spicity (sigma‐pi) diagram. The new method has been applied to the conductivity‐temperature‐depth data collected in the northern South China Sea during a spring cruise in 2011. The water masses in the study region are classified into 13 types according to both the standard deviation of potential spicity in each potential density layer and the water volumetric distribution in the sigma‐pi space. The results suggest that this new method is reasonable and robust for classifying water masses in the sigma‐pi space as compared to previous methods based on the traditional T‐S space. In addition, the westward intrusion of the West Pacific Ocean water to the northern South China Sea can be clearly detected by the tongue‐like potential spicity structure and relatively high potential spicity patches on potential density layers, further verifying the robustness and efficiency of our method in the water mass analysis.
Mission Specific Solar Radiation Environment Model (MSSREM): Peak Flux Model
Authors: Robinson Z. D. , Adams J. H. , Fisher J. H. , Nonnast J. H. , Terry D. C.
Published: June 2020

Coronal mass ejections and solar flares can accelerate high fluxes of energetic particles. Depending on where this solar activity occurs on the sun, these outward moving particles can reach the Earth and enter the Earth's magnetosphere. They can also strike manmade objects in space. If the electronics in space are not protected from these energetic particles, they can cause the spacecraft to reboot, go into “safe mode,” have other anomalies, or cause catastrophic damage and loss of the mission. To protect the mission, the user can employ one or more mitigation strategies. The user may choose to add shielding, choose parts less prone to radiation effects, and/or mitigate by design. Implementing any of these strategies adds cost to the mission, so it is important to frame the design for the purpose of survival in a reference environment, which is severe enough to provide the desired confidence of mission success, but not more. For this reason, models have been developed that construct a design reference environment tailored to a specific mission. In this paper, the Mission Specific Solar Radiation Environment Model (MSSREM) peak flux model will be discussed. MSSREM uses probabilistic modeling techniques to build a design reference environment that can be tailored to a user specified mission start date, mission duration, and confidence level. The model can be run for any space mission outside the Earth's magnetic field and 1 AU from the sun during the years 1953–2055.
Pedotransfer Function for the Brunswick Soil Hydraulic Property Model and Comparison to the van Genuchten‐Mualem Model
Authors: Weber Tobias K. D. , Finkel Michael , da Conceição Gonçalves Maria , Vereecken Harry , Diamantopoulos Efstathios
Published: June 2020

Modeling soil hydraulic properties requires an effective representation of capillary and noncapillary storage and conductivity. This is made possible by using physically comprehensive yet flexible soil hydraulic property models. Such a model (Brunswick [BW] model) was introduced by Weber et al. (2019, https://doi.org/10.1029/2018WR024584), and it overcomes some core deficiencies present in the widely used van Genuchten‐Mualem (VGM) model. We first compared the performance of the BW model to that of the VGM model in its ability to describe water retention and hydraulic conductivity data on a set of measurements of 402 soil samples with textures covering the entire range of classes. Second, we developed a simple transfer function to predict BW parameters based on VGM parameters. Combined with our new function, any existing pedotransfer function for the prediction of the VGM parameters can be extended to predict BW model parameters. Based on information criteria, the smaller variance of the residuals, and a 40% reduction in mean absolute error in the hydraulic conductivity over all samples, the BW model clearly outperforms VGM. This is possible as the BW model explicitly accounts for hydraulic properties of dry soils. With the new pedotransfer function developed in this study, better descriptions of water retention and hydraulic conductivities are possible. We are convinced that this will strengthen the utility of the new model and enable improved field‐scale simulations, climate change impact assessments on water, energy and nutrient fluxes, as well as crop productivity in agroecosystems by soil‐crop and land‐surface modeling. The models and the pedotransfer function are included in an R package spsh (https://cran.r‐project.org/package=spsh).
How COVID-19 Is Affecting Undergraduate Research Experiences
Authors: Sloan Valerie , Haacker Rebecca , Batchelor Rebecca , Garza Corey
Published: June 2020

Limitations on summer research internships imposed by the pandemic are impeding students’ engagement in geoscience education and preparation for careers. The community is acting quickly to adapt.
Eddies Affect Subsurface Phytoplankton and Oxygen Distributions in the North Pacific Subtropical Gyre
Authors: Xiu Peng , Chai Fei
Published: June 2020

The North Pacific Subtropical Gyre (NPSG) is an oligotrophic environment where a number of mesoscale eddies occur. With continuous measurements from Biogeochemical‐Argo (BGC‐Argo) floats, we showed that mesoscale eddies can significantly affect the subsurface chlorophyll maximum (SCM) and subsurface biogenic particles. Different responses of the SCM to the cyclonic and anticyclonic eddies and those between the eddy core and edge region were revealed by combining the results from tracked eddies. The variations in the SCM and subsurface particles were further shown to be statistically linked with changes in the dissolved oxygen in the upper oxygen minimum layer. Such an eddy‐induced oxygen change in the central gyre is unresolved in global‐scale coupled models but can contribute to the oxygen variability in oligotrophic environments.
Scaling of Imbibition Front Dynamics in Heterogeneous Porous Media
Authors: Bakhshian Sahar , Murakami Margaret , Hosseini Seyyed Abolfazl , Kang Qinjun
Published: June 2020

We report a quantitative study on the dynamics of countercurrent imbibition in fractured rock samples with the application of CO2 geosequestration, as the rock matrix is saturated with CO2 and brine exists in the adjacent microfracture. Direct pore‐scale simulations of spontaneous and forced imbibition in a three‐dimensional heterogeneous porous matrix enable us to capture the effect of microscopic properties on the imbibition dynamics as these pore‐level descriptions are ignored in the existing coarse‐grained models. We have established new scaling classes for the propagation of the center of mass of the imbibition front and fluid‐fluid interface broadening. It has become evident that the wettability is a major factor which leads to anomalies in these scaling laws. While the governing capillarity under the water‐wet condition induces fast roughening dynamics of the interface, the adverse effect of capillary pressure under the intermediate‐wet condition leads to a damping effect on the imbibition front fluctuations.
Projected Future Changes in Tropical Cyclones Using the CMIP6 HighResMIP Multimodel Ensemble
Authors: Roberts Malcolm John , Camp Joanne , Seddon Jon , Vidale Pier Luigi , Hodges Kevin , Vannière Benoît , Mecking Jenny , Haarsma Rein , Bellucci Alessio , Scoccimarro Enrico , Caron Louis‐Philippe , Chauvin Fabrice , Terray Laurent , Valcke Sophie , Moine Marie‐Pierre , Putrasahan Dian , Roberts Christopher D. , Senan Retish , Zarzycki Colin , Ullrich Paul , Yamada Yohei , Mizuta Ryo , Kodama Chihiro , Fu Dan , Zhang Qiuying , Danabasoglu Gokhan , Rosenbloom Nan , Wang Hong , Wu Lixin
Published: June 2020

Future changes in tropical cyclone properties are an important component of climate change impacts and risk for many tropical and midlatitude countries. In this study we assess the performance of a multimodel ensemble of climate models, at resolutions ranging from 250 to 25 km. We use a common experimental design including both atmosphere‐only and coupled simulations run over the period 1950–2050, with two tracking algorithms applied uniformly across the models. There are overall improvements in tropical cyclone frequency, spatial distribution, and intensity in models at 25 km resolution, with several of them able to represent very intense storms. Projected tropical cyclone activity by 2050 generally declines in the South Indian Ocean, while changes in other ocean basins are more uncertain and sensitive to both tracking algorithm and imposed forcings. Coupled models with smaller biases suggest a slight increase in average TC 10 m wind speeds by 2050.
New World Meteorological Organization Certified Megaflash Lightning Extremes for Flash Distance (709 km) and Duration (16.73 s) Recorded From Space
Authors: Peterson Michael J. , Lang Timothy J. , Bruning Eric C. , Albrecht Rachel , Blakeslee Richard J. , Lyons Walter A. , Pédeboy Stéphane , Rison William , Zhang Yijun , Brunet Manola , Cerveny Randall S.
Published: June 2020

Identification and validation of atmospheric extremes are essential to monitoring climate change, to addressing engineering and safety concerns, and to promoting technological advancement. An international World Meteorological Organization evaluation committee has critically adjudicated and recommended acceptance of two lightning megaflash events (horizontal mesoscale lightning discharges of >100 km in length) as new global extremes using analysis of Geostationary Lightning Mapper data. The world's greatest extent for an individual lightning flash is a single flash that covered a horizontal distance of 709 ± 8 km (441 ± 5 mi) across parts of southern Brazil on 31 October 2018. The greatest duration for a single lightning flash is 16.730 ± 0.002 s from a flash that developed continuously over northern Argentina on 4 March 2019.
Large‐Amplitude Oscillatory Motion of Mercury's Cross‐Tail Current Sheet
Authors: Poh Gangkai , Sun Weijie , Clink Kellyn M. , Slavin James A. , Dewey Ryan M. , Jia Xianzhe , Raines Jim M. , DiBraccio Gina A. , Espley Jared R.
Published: June 2020

We surveyed 4 years of MESSENGER magnetic field data and analyzed intervals with observations of large‐amplitude oscillatory motions of Mercury's cross‐tail current sheet, or flapping waves, characterized by a decrease in magnetic field intensity and multiple reversals of BX, oscillating with a period on the order of ~4 – 25 seconds. We performed minimum variance analysis (MVA) on each flapping wave event to determine the current sheet normal. Statistical results showed that the flapping motion of the current sheet caused it to warp and tilt in the y‐z plane, which suggests that these flapping waves are kink‐type waves propagating in the cross‐tail direction of Mercury's magnetotail. The occurrence of flapping waves shows a strong preference in Mercury's duskside plasma sheet. We compared our results with the magnetic double‐gradient instability model and examined possible flapping wave excitation mechanism theories from internal (e.g., finite gyroradius effects of planetary sodium ions Na+ on magnetosonic waves) and external (e.g., solar wind variations and K‐H waves) sources.
Numerical Investigations of Interhemispheric Asymmetry due to Ionospheric Conductance
Authors: Lysak R. L. , Song Y. , Waters C. L. , Sciffer M. D. , Obana Y.
Published: June 2020

Due to differences in solar illumination, a geomagnetic field line may have one foot point in a dark ionosphere while the other ionosphere is in daylight. This may happen near the terminator under solstice conditions. In this situation, a resonant wave mode may appear, which has a node in the electric field in the sunlit (high conductance) ionosphere and an antinode in the dark (low conductance) ionosphere. Thus, the length of the field line is one quarter of the wavelength of the wave, in contrast with half‐wave field line resonances in which both ionospheres are nodes in the electric field. These quarter waves have resonant frequencies that are roughly a factor of 2 lower than the half‐wave frequency on the field line. We have simulated these resonances using a fully three‐dimensional model of ULF waves in a dipolar magnetosphere. The ionospheric conductance is modeled as a function of the solar zenith angle, and so this model can describe the change in the wave resonance frequency as the ground magnetometer station varies in local time. The results show that the quarter‐wave resonances can be excited by a shock‐like impulse at the dayside magnetosphere and exhibit many of the properties of the observed waves. In particular, the simulations support the notion that a conductance ratio between day and night foot points of the field line must be greater than about 5 for the quarter waves to exist.
Evaluating Geostationary Lightning Mapper Flash Rates Within Intense Convective Storms
Authors: Rutledge S. A. , Hilburn K. A. , Clayton A. , Fuchs B. , Miller S. D.
Published: June 2020

The Geostationary Lightning Mapper (GLM) marks the first time that lightning observations at storm‐scale resolution are operationally available from geostationary orbit. We evaluate GLM detection efficiency (DE) for a special class of convective storms characterized by anomalous charge structures. These storms are anomalous as their internal layered charge structure departs from the tripole charge structure model, where midlevel negative charge is situated between upper and lower positive charge layers. Anomalous storms are characterized by extreme flash rates, low median flash heights, and intense precipitation. Ground truth information on lightning flash rates is provided by Lightning Mapping Arrays (LMA), which measure VHF radio frequency emissions produced by electrical breakdown. This study contrasts two regions: Colorado, where electrically “anomalous” storms are numerous, and Alabama, where they are rare. This study analyzes GLM DE as a function of the precipitation water path, cloud water path, and lightning properties from LMA. The GLM DE is found to vary with the geometric size of the flash and with cloud water path, the latter depending on flash height and cloud water content. Optical scattering (attenuation) by precipitation‐sized particles does not appear to be a factor since precipitation particles contain much less surface area than cloud particles. The size of the flash is correlated with its optical brightness, and the cloud water path is correlated with optical extinction. Regional differences in GLM DE remain that appear to be related to sensor viewing geometry and day versus night sensitivity differences.
Tectonics of the Asela‐Langano Margin, Main Ethiopian Rift (East Africa)
Authors: Corti Giacomo , Sani Federico , Florio Alessio A. , Greenfield Tim , Keir Derek , Erbello Asfaw , Muluneh Ameha A. , Ayele Atalay
Published: June 2020

We provide insights into the tectonics of the Asela‐Langano margin, at the eastern boundary of the central Main Ethiopian Rift, East Africa, by combining field structural data, remote sensing, analysis of the distribution of faults, new dating of faulted material, and analysis of seismicity. The area is characterized by the occurrence of two fault sets: boundary and axial (Wonji) faults, oriented NE‐SW and NNE‐SSW, respectively. Boundary faults show a complex arrangement in the lake Langano area where they display a rhomboidal pattern, due to the presence of NW‐SE‐trending structures, likely related to preexisting transverse fabrics (the so‐called Langano Rhomboidal Fault System). Overall, our analysis supports a structure of the margin characterized by a monocline affected by a series of minor horsts and grabens; this confirms a marked asymmetry of the central Main Ethiopian Rift, with a master fault system on the opposite, western margin. Cumulative paleostress analysis indicates an overall N115°E extension across the Asela‐Langano margin; however, a local variation of the extension direction from axial (Wonji) faults (∼N90°E) to the boundary faults (∼N115°E) can be observed, pointing to a stress reorientation at rift margins. New 14C dating of faulted material and seismicity analysis indicate Late Pleistocene–Holocene and current activity on several normal faults affecting the margin. This suggests that extensional deformation in the central Main Ethiopian Rift is accommodated at the rift margins, with subordinate activity on axial faults, supporting that this rift sector reflects an intermediate stage of rift evolution.
Three‐Dimensional Flow Structures and Morphodynamic Evolution of Microtidal Meandering Channels
Authors: Finotello Alvise , Ghinassi Massimiliano , Carniello Luca , Belluco Enrica , Pivato Mattia , Tommasini Laura , D'Alpaos Andrea
Published: June 2020

The planform evolution of tidal meanders is driven by interactions between channel morphology and periodically reversing tidal flows, which feed back into the development of erosional and depositional patterns. However, the paucity of quantitative data has so far undermined detailed analyses about the geomorphic effects of tidal flows within tidal meanders. Here we aim to bond the morphodynamic evolution of tidal meanders with the structure of three‐dimensional flow that shapes them. By means of an acoustic Doppler current profiler, we have surveyed the flow fields over three different tidal meandering channels in the salt marshes at San Felice (Venice lagoon, Italy), each characterized by distinct planform morphology and evolutionary dynamics. Mutually evasive paths followed by the maximum ebb and flood streamwise velocities determine periodic changes in both the position and the orientation of curvature‐induced cross‐stream flows. These secondary flows can be locally disrupted by patches of submerged vegetation, especially in meanders of small size, with direct implications for the morphodynamic evolution of meander bends. The latter is further affected by flow separation in sharp bends. Flow separation effectively reduces channel width, enhancing bank erosion due to increasing flow velocities. Moreover, it creates low‐velocity zones of recirculating flows at both the inner and outer banks, thereby promoting the formation of point bars and concave‐bank benches, respectively. By relating three‐dimensional flow structure to patterns of channel change, our results provide a first step to unravel the relation between flows and forms within tidal meanders, whose planform characteristics may differ greatly from their fluvial counterparts.
Stress inoculation in mice induces global resilience
Authors: Ayash Sarah , Schmitt Ulrich , Lyons David M. , Müller Marianne B.
Published: June 2020

Each year, more than half a billion people in the world are affected by stress-related health disorders. Consequently, there is an urgent need for new insights to guide interventions designed to increase stress resilience. Studies of humans and various animals have uncovered the process of stress inoculation, in which exposure to mild stressors enhances subsequent stress resilience. Here, we investigate whether stress inoculation-induced resilience in mice consistently occurs across a multiplicity of different stress contexts (tests). C57BL/6 J adult male mice were randomised either to stress inoculation training (n = 36) or to a non-inoculated, but handled control condition (n = 36). Thereafter, indications of coping and resilience were assessed during (i) acute social defeat in a context similar to that used for stress inoculation training, and (ii) fear conditioning and learned extinction in a novel context. Stress inoculation effects were also assessed during (iii) tail-suspension and (iv) open-field tests that each represent milder stressors. Stress-inoculated mice showed more active defence behaviour during acute social defeat, higher sociability before and after defeat, and greater indications of learned extinction of conditioned fear compared to non-inoculated control mice. Stress-inoculated mice also responded with diminished tail-suspension immobility and open-field defecation. Results suggest that stress inoculation protects against various stressors that differ in quality and relative intensity. Stress inoculation research in mice may serve as the basis for mechanistic studies of global resilience in humans.
Author Correction: Immune cell profiling of COVID-19 patients in the recovery stage by single-cell sequencing
Authors: Wen Wen , Su Wenru , Tang Hao , Le Wenqing , Zhang Xiaopeng , Zheng Yingfeng , Liu Xiuxing , Xie Lihui , Li Jianmin , Ye Jinguo , Dong Liwei , Cui Xiuliang , Miao Yushan , Wang Depeng , Dong Jiantao , Xiao Chuanle , Chen Wei , Wang Hongyang
Published: June 2020

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
An alternative route of bacterial infection associated with a novel resistance locus in the Daphnia–Pasteuria host–parasite system
Authors: Bento Gilberto , Fields Peter D. , Duneau David , Ebert Dieter
Published: June 2020

To understand the mechanisms of antagonistic coevolution, it is crucial to identify the genetics of parasite resistance. In the Daphnia magna–Pasteuria ramosa host–parasite system, the most important step of the infection process is the one in which P. ramosa spores attach to the host’s foregut. A matching-allele model (MAM) describes the host–parasite genetic interactions underlying attachment success. Here we describe a new P. ramosa genotype, P15, which, unlike previously studied genotypes, attaches to the host’s hindgut, not to its foregut. Host resistance to P15 attachment shows great diversity across natural populations. In contrast to P. ramosa genotypes that use foregut attachment, P15 shows some quantitative variation in attachment success and does not always lead to successful infections, suggesting that hindgut attachment represents a less-efficient infection mechanism than foregut attachment. Using a Quantitative Trait Locus (QTL) approach, we detect two significant QTLs in the host genome: one that co-localizes with the previously described D. magna PR locus of resistance to foregut attachment, and a second, major QTL located in an unlinked genomic region. We find no evidence of epistasis. Fine mapping reveals a genomic region, the D locus, of ~13 kb. The discovery of a second P. ramosa attachment site and of a novel host-resistance locus increases the complexity of this system, with implications for both for the coevolutionary dynamics (e.g., Red Queen and the role of recombination), and for the evolution and epidemiology of the infection process.
Towards actionable research frameworks for sustainable intensification in high-yielding rice systems
Authors: Tseng Meng-Chun , Roel Alvaro , Deambrosi Enrique , Terra José A. , Zorrilla Gonzalo , Riccetto Sara , Pittelkow Cameron M.
Published: June 2020

New research frameworks that simultaneously address production and environmental goals are required to identify promising sustainable intensification options in high-yielding cereal systems. Here we estimated potential changes in environmental footprint associated with crop management practices aimed at breaking the yield ceiling for rice production in Uruguay. Results from a regional survey were combined with field experiments to integrate impacts on productivity and sustainability at two different intensification levels (average-yielding and high-yielding). Survey results indicate that high-yielding farmers produced 14% more grain compare to the regional average (7900 kg ha−1), with 25% to 99% lower agrochemical contamination risk and similar nitrogen use efficiency and carbon footprint. In on-farm trials, the alternative management practices increased yield beyond that of high-yielding farmers by up to 7% in small plots (8 site-years) and 15% in field-scale comparisons (6 site-years), yet an ex post assessment of environmental indicators shows significant decline of resource use efficiencies and increased carbon footprint. Thus, yield gains were not able to compensate for increased environmental footprint, highlighting the challenge of advancing the dual goals of SI in production systems nearing the yield ceiling. This study provides a simple but powerful framework for advancing SI in mainstream cereal production systems based on cost-effective modifications to existing agronomic experiments.
Plasma Electrolytic Oxidation as a Feasible Surface Treatment for Biomedical Applications: an in vivo study
Authors: Polo Tárik Ocon Braga , Silva William Phillip Pereira , Momesso Gustavo Antonio Correa , Lima-Neto Tiburtino José , Barbosa Stéfany , Cordeiro Jairo Matozinho , Hassumi Jaqueline Suemi , da Cruz Nilson Cristino , Okamoto Roberta , Barão Valentim A. R. , Faverani Leonardo P.
Published: June 2020

Objectives: In this in vivo animal study, we evaluated the effect of plasma electrolytic oxidation (PEO) coating on the topographic and biological parameters of implants installed in rats with induced osteoporosis and low-quality bones. Materials and methods: In total 44 Wistar rats (Rattus novergicus), 6 months old, were submitted to ovariectomy (OXV group) and dummy surgery (SHAM group). After 90 days, the ELISA test was performed and the ovariectomy effectiveness was confirmed. In each tibial metaphysis, an implant with PEO coating containing Ca2+ and P5+ molecules were installed, and the other tibia received an implant with SLA acid etching and blasting (AC) (control surface). After 42 days, 16 rats from each group were euthanized, their tibias were removed for histological and immunohistochemical analysis (OPG, RANKL, OC and TRAP), as well as reverse torque biomechanics. Data were submitted to One-way ANOVA or Kruskal-Wallis tests, followed by a Tukey post-test; P < 0.05. Histological analyses showed higher bone neoformation values among the members of the PEO group, SHAM and OVX groups. Immunohistochemical analysis demonstrated equilibrium in all groups when comparing surfaces for TRAP, OC and RANKL (P > 0.05), whereas OPG showed higher PEO labeling in the OVX group (P < 0.05). Biomechanical analysis showed higher reverse torque values (N.cm) for PEO, irrespective of whether they were OVX or SHAM groups (P < 0.05). Conclusion: The results indicated that the PEO texturing method favored bone formation and showed higher bone maturation levels during later periods in osteoporotic rats.
Sanguisorba officinalis L. derived from herbal medicine prevents intestinal inflammation by inducing autophagy in macrophages
Authors: Yasueda Asuka , Kayama Hisako , Murohashi Michiko , Nishimura Junichi , Wakame Koji , Komatsu Ken-ichi , Ogino Takayuki , Miyoshi Norikatsu , Takahashi Hidekazu , Uemura Mamoru , Matsuda Chu , Kitagawa Toru , Takeda Kiyoshi , Ito Toshinori , Doki Yuichiro , Eguchi Hidetoshi , Shimizu Shigeomi , Mizushima Tsunekazu
Published: June 2020

Disturbed activation of autophagy is implicated in the pathogenesis of inflammatory bowel disease. Accordingly, several autophagy-related genes have been identified as Crohn’s disease susceptibility genes. We screened the autophagy activators from a library including 3,922 natural extracts using a high-throughput assay system. The extracts identified as autophagy activators were administered to mice with 2% dextran sodium sulfate (DSS). Among the autophagy inducers, Sanguisorba officinalis L. (SO) suppressed DSS-induced colitis. To identify the mechanism by which SO ameliorates colitis, epithelial cell and innate myeloid cells-specific Atg7-deficient mice (Villin-cre; Atg7f/f and LysM-cre; Atg7f/f mice, respectively) were analyzed. SO-mediated inhibition of colitis was observed in Villin-cre; Atg7f/f mice. However, SO and a mixture of its components including catechin acid, ellagic acid, gallic acid, and ziyuglycoside II (Mix4) did not suppressed colitis in LysM-cre; Atg7f/f mice. In large intestinal macrophages (Mφ) of Atg7f/f mice, SO and Mix4 upregulated the expression of marker genes of anti-inflammatory Mφ including Arg1, Cd206, and Relma. However, these alterations were not induced in LysM-cre; Atg7f/f mice. These findings indicate that SO and its active components ameliorate DSS-induced colitis by providing intestinal Mφ with anti-inflammatory profiles via promotion of Atg7-dependent autophagy.
Non-canonical chemical feedback self-limits nitric oxide-cyclic GMP signaling in health and disease
Authors: Dao Vu Thao-Vi , Elbatreek Mahmoud H. , Deile Martin , Nedvetsky Pavel I. , Güldner Andreas , Ibarra-Alvarado César , Gödecke Axel , Schmidt Harald H. H. W.
Published: June 2020

Nitric oxide (NO)-cyclic GMP (cGMP) signaling is a vasoprotective pathway therapeutically targeted, for example, in pulmonary hypertension. Its dysregulation in disease is incompletely understood. Here we show in pulmonary artery endothelial cells that feedback inhibition by NO of the NO receptor, the cGMP forming soluble guanylate cyclase (sGC), may contribute to this. Both endogenous NO from endothelial NO synthase and exogenous NO from NO donor compounds decreased sGC protein and activity. This effect was not mediated by cGMP as the NO-independent sGC stimulator, or direct activation of cGMP-dependent protein kinase did not mimic it. Thiol-sensitive mechanisms were also not involved as the thiol-reducing agent N-acetyl-L-cysteine did not prevent this feedback. Instead, both in-vitro and in-vivo and in health and acute respiratory lung disease, chronically elevated NO led to the inactivation and degradation of sGC while leaving the heme-free isoform, apo-sGC, intact or even increasing its levels. Thus, NO regulates sGC in a bimodal manner, acutely stimulating and chronically inhibiting, as part of self-limiting direct feedback that is cGMP independent. In high NO disease conditions, this is aggravated but can be functionally recovered in a mechanism-based manner by apo-sGC activators that re-establish cGMP formation.