bluuebunny/crossref_metadata_2025 huggingface dataset:
Future Fire Impacts on Smoke Concentrations, Visibility, and Health in the Contiguous United States
Authors: Ford B. , Val Martin M. , Zelasky S. E. , Fischer E. V. , Anenberg S. C. , Heald C. L. , Pierce J. R.
Published: July 2018

Fine particulate matter (PM2.5) from U.S. anthropogenic sources is decreasing. However, previous studies have predicted that PM2.5 emissions from wildfires will increase in the midcentury to next century, potentially offsetting improvements gained by continued reductions in anthropogenic emissions. Therefore, some regions could experience worse air quality, degraded visibility, and increases in population‐level exposure. We use global climate model simulations to estimate the impacts of changing fire emissions on air quality, visibility, and premature deaths in the middle and late 21st century. We find that PM2.5 concentrations will decrease overall in the contiguous United States (CONUS) due to decreasing anthropogenic emissions (total PM2.5 decreases by 3% in Representative Concentration Pathway [RCP] 8.5 and 34% in RCP4.5 by 2100), but increasing fire‐related PM2.5 (fire‐related PM2.5 increases by 55% in RCP4.5 and 190% in RCP8.5 by 2100) offsets these benefits and causes increases in total PM2.5 in some regions. We predict that the average visibility will improve across the CONUS, but fire‐related PM2.5 will reduce visibility on the worst days in western and southeastern U.S. regions. We estimate that the number of deaths attributable to total PM2.5 will decrease in both the RCP4.5 and RCP8.5 scenarios (from 6% to 4–5%), but the absolute number of premature deaths attributable to fire‐related PM2.5 will double compared to early 21st century. We provide the first estimates of future smoke health and visibility impacts using a prognostic land‐fire model. Our results suggest the importance of using realistic fire emissions in future air quality projections.
Maximum Magnitude Forecast in Hydraulic Stimulation Based on Clustering and Size Distribution of Early Microseismicity
Authors: Afshari Moein Mohammad Javad , Tormann Thessa , Valley Benoît , Wiemer Stefan
Published: July 2018

We interpreted the spatial clustering and size distribution of induced microseismicity observed during the stimulation of an enhanced geothermal system beneath Basel by comparison with scale‐invariant synthetic data derived from discrete fracture network models. We evaluated microseimic specific influential factors including the effect of hypocentral location uncertainties, existence of a fractured zone and repeating events on the observed spatial organization. Using a dual power‐law model originally developed in the context of discrete fracture network modeling, we developed theoretically the relationships among spatial clustering and magnitude distributions. We applied this model to the Basel data set and showed that the spatial clustering characteristics presented stationary properties during the hydraulic stimulation. Based on this observation, we proposed a statistical seismicity model calibrated on the scaling of early stimulation spatial patterns that is capable of forecasting the maximum magnitude of induced events with increasing injection time and stimulated volume.
Wave Generation of Gravity‐Driven Sediment Flows on a Predominantly Sandy Seabed
Authors: Flores Raúl P. , Rijnsburger Sabine , Meirelles Saulo , Horner‐Devine Alexander R. , Souza Alejandro J. , Pietrzak Julie D. , Henriquez Martijn , Reniers Ad
Published: July 2018

Wave‐supported gravity flows (WSGFs) generate rates of sediment flux far exceeding other cross‐shelf transport processes, contributing disproportionately to shelf morphology and net cross‐shelf fluxes of sediment in many regions worldwide. However, the conditions deemed necessary for the formation of WSGF limit them to a narrow set of shelf conditions; they have been observed exclusively in regions where the seabed consists of very fine‐grained sediment and typically co‐occur with nearby river flood events. Here we document the occurrence of a WSGF event on a predominantly sandy seabed and in the absence of a preceding river flood. Our measurements confirm that the dynamics are governed by the friction‐buoyancy balance observed in other WSGF and that WSGF can form in mixed grain‐size environments and transport high concentrations of sand. The occurrence of WSGF on a predominantly sandy seabed suggests that they may occur under a much wider range of conditions and, given the global prevalence of sandy shelves, they may be a more frequent and more ubiquitous feature of shelf dynamics than previously thought.
Saturn's Global Zonal Winds Explored by Cassini/VIMS 5‐μm Images
Authors: Studwell Aaron , Li Liming , Jiang Xun , Baines Kevin H. , Fry Patrick M. , Momary Thomas W. , Dyudina Ulyana A.
Published: July 2018

The Cassini Visual and Infrared Mapping Spectrometer (VIMS) 5‐μm images are used to derive Saturn's global zonal winds around the 2,000‐hPa level. The comparison of zonal winds between 2,000 and 300–500 hPa shows a general consistency of wind structure between the two pressure levels on a global scale. However at some latitudes, the magnitude of the zonal winds differs between these levels. The equatorial zonal winds are stronger downward, while the zonal winds in the middle and high latitudes are generally weaker downward. These new wind measurements also imply that barotropic and baroclinic instabilities probably exist through the relatively deep atmosphere at some latitudes. Finally, our analysis reveals that the VIMS winds in the two polar regions are basically constant with time except for a westerly jet centered at ~88°N, which decreased from 135 ± 7 m/s in 2008 to 91 ± 12 m/s in 2017.
Martian Electron Temperatures in the Subsolar Region: MAVEN Observations Compared to a One‐Dimensional Model
Authors: Peterson W. K. , Fowler C. M. , Andersson L. A. , Thiemann E. M. B. , Jain S. K. , Mayyasi M. , Esman T. M. , Yelle R. , Benna M. , Espley J.
Published: July 2018

Prior to the Mars Atmospheric Volatile EvolutioN (MAVEN) mission, altitude profiles of the electron temperature in the Martian thermosphere were measured only twice. Because the rates of several geophysically important processes depend strongly on the electron temperature, models of the Martian thermosphere and atmospheric escape rates have not been well constrained. In this paper, we use densities and temperatures measured by MAVEN instruments and the one‐dimensional model of Matta et al. (2014, https://doi.org/10.1016/j.icarus.2013.09.006) to test our understanding of the processes that determine the electron temperature. Our analysis is limited to inbound orbits where the magnetic field is within 30° of horizontal and the satellite is within 30° of the subsolar point at altitudes from 120 to 250 km. We introduce empirically adjusted electron temperatures below 180 km, where the MAVEN electron temperature measurements are known to be biased high. We introduce the concept of a local electron heating efficiency, which we define at a given altitude as the ratio of electron heating from photoionization to the total extreme ultraviolet energy deposited. Our analysis shows that MAVEN observations are consistent with the one‐dimensional model below ~210 km if the electron heating efficiency varies with altitude, and the electron temperature is within the empirical bounds below 180 km we introduced. It indicates that above ~210 km electron heat conduction dominates extreme ultraviolet heating in determining electron temperature. Our analysis also suggests that in the subsolar region electrons and neutrals are in thermal equilibrium below 120 km.
The Response Time of Equatorial Ionization Anomaly Crest: A Unique Precursor to the Time of Equatorial Spread F Initiation
Authors: Aswathy R. P. , Manju G. , Sunda Surendra
Published: July 2018

The time delay with which the magnitude and location of the total electron content (TEC) at the equatorial ionization anomaly (EIA) crest responds to the mean height of the F layer (hmF2) is examined seasonally using the ionosonde data at Trivandrum and the Global Positioning System data at different stations in the EIA region for low and high solar activity years. The study brings out the fact that for the low solar activity year, the crest TEC responds fastest in winter solstice compared to other seasons. Further, the response time of the crest is found to decrease with solar activity. The seasonal variation in the EIA response time is attributed to the modulation by meridional neutral winds, whereas the solar activity variation seems to be basically controlled by the diffusion times and the background ionization gradients in the respective epochs. The derived relationship between EIA crest location/magnitude and hmF2 for any season can be used for prediction purposes. Furthermore, this study for the first time establishes the relation of EIA response time to equatorial spread F (ESF) start time, for days when the F layer is in the neutral dynamically controlled domain. The deleterious effects of ESF irregularities on communication and navigation systems are well known, and the above result is significant in this context. The present study has the potential to be extended into a model to predict the ESF start time, from the EIA response time, earlier in the day.
Electron Dynamics in Magnetosheath Mirror‐Mode Structures
Authors: Yao S. T. , Shi Q. Q. , Liu J. , Yao Z. H. , Guo R. L. , Ahmadi N. , Degeling A. W. , Zong Q. G. , Wang X. G. , Tian A. M. , Russell C. T. , Fu H. S. , Pu Z. Y. , Fu S. Y. , Zhang H. , Sun W. J. , Li L. , Xiao C. J. , Feng Y. Y. , Giles B. L.
Published: July 2018

Mirror‐mode structures are widely observed in space plasma environments. Although plasma features within the structures have been extensively investigated in theoretical models and numerical simulations, relatively few observational studies have been made, due to a lack of high‐cadence measurements of particle distributions in previous space missions. In this work, electron dynamics associated with mirror‐mode structures are studied based on Magnetospheric Multiscale observations of electron pitch angle distributions. We define mirror‐mode peaks/troughs as the region where the magnetic field strength is greater/smaller than the mean field. The observations show that most electrons are trapped inside the mirror‐mode troughs and display a donut‐like pitch angle distribution configuration. Besides the trapped electrons in mirror‐mode troughs, we find that electrons are also trapped between ambient mirror‐mode peaks and coexisting untrapped electrons within the mirror‐mode structure. Analysis shows that the observed donut‐like electron distributions are the result of betatron cooling and the spatial dependence of electron pitch angles within the structure.
Modeling the Dawn/Dusk Asymmetry of Field Line Resonances
Authors: Wright Andrew N. , Elsden Tom , Takahashi Kazue
Published: July 2018

Field line resonances (FLRs) are observed to occur preferentially and have larger amplitudes at dawn compared to dusk. We present simulations of FLR excitation in a magnetospheric waveguide that can reproduce this behavior. Crucially, our equilibrium is asymmetric about noon. Even when this system is driven in a symmetric fashion about noon, the fast waves that are established in the magnetosphere develop asymmetries—as do the FLRs they excite. Fast mode ray trajectories are employed to show that the asymmetry evolves due to refraction. Preferential FLR excitation at dawn is further reinforced by calculating the Resonance Map. This shows that the Resonant Zone at dawn coincides with a large‐amplitude coherent fast mode driver, which is not the case at dusk. These factors result in FLRs having a larger amplitude at dawn compared to dusk.
The Relation Between Ground Motion, Earthquake Source Parameters, and Attenuation: Implications for Source Parameter Inversion and Ground Motion Prediction Equations
Authors: Lior Itzhak , Ziv Alon
Published: July 2018

Theoretical equations relating the root‐mean‐square (rms) of the far‐field ground motions with earthquake source parameters and attenuation are derived for Brune's omega‐squared model that is subject to attenuation. This set of model‐based predictions paves the way for a completely new approach for earthquake source parameter inversion and forms the basis for new physics‐based ground motion prediction equations (GMPEs). The equations for ground displacement, velocity, and acceleration constitute a set of three independent equations with three unknowns: the seismic moment, the stress drop, and the attenuation parameter. These are used for source parameter inversion that circumvents the time‐to‐frequency transformation. Initially, the two source parameters and the attenuation constant are solved simultaneously for each seismogram. Sometimes, however, this one‐step inversion results in ambiguous solutions. Under such circumstances, the procedure proceeds to a two‐step approach, in which a station‐specific attenuation parameter is first determined by averaging the set of attenuation parameters obtained from seismograms whose one‐step inversion yields well‐constrained solutions. Subsequently, the two source parameters are solved using the averaged attenuation parameter. It is concluded that the new scheme is more stable than a frequency domain method, resulting in considerably less within‐event source parameter variability. The above results together with rms‐to‐peak ground motion relations are combined to give first‐order GMPEs for acceleration, velocity, and displacement. In contrast to empirically based GMPEs, the ones introduced here are extremely simple and readily implementable, even in low‐seismicity regions, where the earthquake catalog lacks strong ground motion records.
Tidal Modulation and Tectonic Implications of Tremors in Taiwan
Authors: Chen Kate Huihsuan , Tai Hsin‐Ju , Ide Satoshi , Byrne Timothy B. , Johnson Christopher W.
Published: July 2018

We present results from 6 years of tremor observations in a continental subduction zone where the continental crust of Eurasia is colliding with the Philippine Sea Plate, forming a collisional orogen. During 2007–2012, 1,893 tremor events with durations ranging from 60 to 2,216 s were identified and located. Spectral analysis of the tremor times reveals several sharp peaks that correlate with the semi annual, semidiurnal, and diurnal constituents, indicating a strong tidal and seasonal modulation. When the tidal stresses and stressing rates are compared with tremor activities, we find that the percent excess number of events increases with amplitude of shear stress and tensile stress but not with shear stressing rate. The percent excess reaches a mean value of 150% for highest shear stress at 3.5 kPa. Such high correlation with tidal shear stress is consistent with the observation from tidal records, where 76–82% of tremors occurred at higher than the median water level at tide gauge stations on the east coast. Spatially, the ambient tremors appear to form a steep, southeast dipping ellipsoidal structure at depths of 15 to 45 km in the southern part of the collisional orogen where the continental crust of Eurasia has been subducted, metamorphosed, and imbricated. We propose a weak fault model for the tremor zone that represents the initiation or reactivation of a brittle‐ductile shear zone deep in the crust and reconciles both the steeply dipping and gently dipping fault geometries proposed previously from different studies.
Precipitation Origins and Key Drivers of Precipitation Isotope (18O, 2H, and 17O) Compositions Over Windhoek
Authors: Kaseke Kudzai Farai , Wang Lixin , Wanke Heike , Tian Chao , Lanning Matthew , Jiao Wenzhe
Published: July 2018

Southern African climate is characterized by large precipitation variability, and model precipitation estimates can vary by 70% during summer. This may be partly attributed to underestimation and lack of knowledge of the exact influence of the Atlantic Ocean on precipitation over the region. The current study models trajectories of precipitation events sampled from Windhoek (2012–2016), coupled with isotopes (δ18O, δ2H, δ17O, d, and δ′17O‐δ′18O) to determine key local drivers of isotope compositions as well as infer source evaporative conditions. Multiple linear regression analyses suggest that key drivers of isotope compositions (relative humidity, precipitation amount, and air temperature) account for 47–53% of δ18O, δ2H, and δ17O variability. Surprisingly, precipitation δ18O, δ2H, and δ17O were independent of precipitation type (stratiform versus convective), and this may be attributed to greater modification of stratiform compared to convective raindrops, leading to convergence of isotopes from these precipitation types. Trajectory analyses showed that 78% and 21% of precipitation events during the period originated from the Indian and South Atlantic Oceans, respectively. Although precipitation from the Atlantic Ocean was significantly enriched compared to that from the Indian Ocean (p < 0.05), d was similar, suggesting significant local modification (up to 55% of d variability). Therefore, d may not be a conservative tracer of evaporation conditions at the source, at least for Windhoek. The δ′17O‐δ′18O appeared to be a better alternative to d, consistent with trajectory analyses, and appeared to differentiate El Niño from non‐El Niño droughts. Thus, δ′17O‐δ′18O could be a novel tool to identify drought mechanisms.
Mars H Escape Rates Derived From MAVEN/IUVS Lyman Alpha Brightness Measurements and Their Dependence on Model Assumptions
Authors: Chaffin M. S. , Chaufray J. Y. , Deighan J. , Schneider N. M. , Mayyasi M. , Clarke J. T. , Thiemann E. , Jain S. K. , Crismani M. M. J. , Stiepen A. , Eparvier F. G. , McClintock W. E. , Stewart A. I. F. , Holsclaw G. M. , Montmessin F. , Jakosky B. M.
Published: July 2018

Mars has lost a large fraction of its water to space, with the H component of this loss thought to occur mainly as a result of thermal (Jeans) escape from the upper atmosphere. Constraints on H loss have historically been made using hydrogen Lyman alpha (121.6 nm) light scattered in the planet's extended upper atmosphere or corona. Here we employ observations from the Mars Atmosphere and Volatile Evolution (MAVEN) mission's Imaging Ultraviolet Spectrograph (IUVS) to constrain H escape in December 2014 and August 2016, when MAVEN observed the dayside corona at low latitude. To obtain adequate fits and address systematic sources of uncertainty including instrument calibration, we fit in exobase number density and escape rate instead of density and temperature, employing Markov Chain Monte Carlo techniques. This produces better model fits to data than most previous analyses. When we assume a single population of H atoms, we obtain H temperatures inconsistent with expected trends and a shape mismatch between observed and modeled profiles, similar to previous studies. Introducing either a second population of H (at a distinct temperature and density) or adding deuterium to the corona allows for essentially perfect fits. Despite this model ambiguity, derived loss rates for both periods are within a factor of four, 3.3–8.8×108cm−2/s in December 2014 (Ls∼250) and 0.6–2.3×108cm−2/s in August 2016 (Ls∼200). These rates are similar to those found in prior studies and confirm the known seasonal trend—doing so while incorporating the substantial uncertainty in absolute calibration insufficiently explored by previous studies.
Altered cerebellar–insular–parietal–cingular subnetwork in adolescents in the earliest stages of anorexia nervosa: a network–based statistic analysis
Authors: Gaudio Santino , Olivo Gaia , Beomonte Zobel Bruno , Schiöth Helgi B.
Published: July 2018

To date, few functional magnetic resonance imaging (fMRI) studies have explored resting-state functional connectivity (RSFC) in long-lasting anorexia nervosa (AN) patients via graph analysis. The aim of the present study is to investigate, via a graph approach (i.e., the network-based statistic), RSFC in a sample of adolescents at the earliest stages of AN (i.e., AN duration less than 6 months). Resting-state fMRI data was obtained from 15 treatment-naive female adolescents with AN restrictive type (AN-r) in its earliest stages and 15 age-matched healthy female controls. A network-based statistic analysis was used to isolate networks of interconnected nodes that differ between the two groups. Group comparison showed a decreased connectivity in a sub-network of connections encompassing the left and right rostral ACC, left paracentral lobule, left cerebellum (10th sub-division), left posterior insula, left medial fronto-orbital gyrus, and right superior occipital gyrus in AN patients. Results were not associated to alterations in intranodal or global connectivity. No sub-networks with an increased connectivity were identified in AN patients. Our findings suggest that RSFC may be specifically affected at the earliest stages of AN. Considering that the altered sub-network comprises areas mainly involved in somatosensory and interoceptive information and processing and in emotional processes, it could sustain abnormal integration of somatosensory and homeostatic signals, which may explain body image disturbances in AN. Further studies with larger samples and longitudinal designs are needed to confirm our findings and better understand the role and consequences of such functional alterations in AN.
Attosecond coherent control of free-electron wave functions using semi-infinite light fields
Authors: Vanacore G. M. , Madan I. , Berruto G. , Wang K. , Pomarico E. , Lamb R. J. , McGrouther D. , Kaminer I. , Barwick B. , García de Abajo F. Javier , Carbone F.
Published: July 2018

Light–electron interaction is the seminal ingredient in free-electron lasers and dynamical investigation of matter. Pushing the coherent control of electrons by light to the attosecond timescale and below would enable unprecedented applications in quantum circuits and exploration of electronic motions and nuclear phenomena. Here we demonstrate attosecond coherent manipulation of a free-electron wave function, and show that it can be pushed down to the zeptosecond regime. We make a relativistic single-electron wavepacket interact in free-space with a semi-infinite light field generated by two light pulses reflected from a mirror and delayed by fractions of the optical cycle. The amplitude and phase of the resulting electron–state coherent oscillations are mapped in energy-momentum space via momentum-resolved ultrafast electron spectroscopy. The experimental results are in full agreement with our analytical theory, which predicts access to the zeptosecond timescale by adopting semi-infinite X-ray pulses.
Anomalous mechanical behavior of nanocrystalline binary alloys under extreme conditions
Authors: Turnage S. A. , Rajagopalan M. , Darling K. A. , Garg P. , Kale C. , Bazehhour B. G. , Adlakha I. , Hornbuckle B. C. , Williams C. L. , Peralta P. , Solanki K. N.
Published: July 2018

Fundamentally, material flow stress increases exponentially at deformation rates exceeding, typically, ~103 s−1, resulting in brittle failure. The origin of such behavior derives from the dislocation motion causing non-Arrhenius deformation at higher strain rates due to drag forces from phonon interactions. Here, we discover that this assumption is prevented from manifesting when microstructural length is stabilized at an extremely fine size (nanoscale regime). This divergent strain-rate-insensitive behavior is attributed to a unique microstructure that alters the average dislocation velocity, and distance traveled, preventing/delaying dislocation interaction with phonons until higher strain rates than observed in known systems; thus enabling constant flow-stress response even at extreme conditions. Previously, these extreme loading conditions were unattainable in nanocrystalline materials due to thermal and mechanical instability of their microstructures; thus, these anomalies have never been observed in any other material. Finally, the unique stability leads to high-temperature strength maintained up to 80% of the melting point (~1356 K).
Author Correction: Design of high-strength refractory complex solid-solution alloys
Authors: Singh Prashant , Sharma Aayush , Smirnov A. V. , Diallo Mouhamad S. , Ray Pratik K. , Balasubramanian Ganesh , Johnson Duane D.
Published: July 2018

The caption of Fig. 6 and the main text contained an error in the chemical formula of the “(MozW1−z)0.85Ta0.10(TiZr)0.05” alloy; it has now been corrected to “(Mo1−zWz)0.85Ta0.10(TiZr)0.05”. Figure 5 also contained an erroneous text box, which has now been removed. This has now been corrected in both the PDF and HTML version of this article.
Evolutionary significance of antiparasite, antipredator and learning phenotypes of avian nest defence
Authors: Campobello Daniela , Sealy Spencer G.
Published: July 2018

Avian nest defence, which is expected to serve both antiparasite and antipredator functions, may benefit or be detrimental to birds, although selective forces that potentially operate on nest defence have not been quantified as a whole. Together with fitness values, we analysed two traits of nest defence, intensity and plasticity, in two distantly related passerine species, yellow warbler (Setophaga petechia) in North America and reed warbler (Acrocephalus scirpaceus) in Europe, both favourite host species for brood parasites. Breeders that escaped parasitism were the most vocal among reed warblers, whereas there was no specific defence phenotype that predicted prevention of parasitism in yellow warblers. Breeders that escaped nest predation were, in both species, those with the most distractive response at the first exposure to a nest-threatening event, such as the experimental predation or parasitism simulated at the nest. However, increasing defence intensity benefited yellow warblers but was detrimental to reed warblers, because intense defence responses attracted predators. Adaptiveness of nest defence was revealed by nest defence phenotypes when examined in concert with the seasonal fitness (i.e. measures of reproductive success). Results revealed selective forces favoured yellow warblers with strong defence phenotypes. Opposite forces were instead revealed among reed warblers whose favoured phenotypes were strong, yet less flexible, defenders.
Effect of Transportation on Cultured Limbal Epithelial Sheets for Worldwide Treatment of Limbal Stem Cell Deficiency
Authors: Utheim O. A. , Lyberg T. , Eidet J. R. , Raeder S. , Sehic A. , Roald B. , Messelt E. , de la Paz M. F. , Dartt D. A. , Utheim T. P.
Published: July 2018

Limbal stem cell deficiency can be treated with transplantation of cultured human limbal epithelial cells (LEC). It can be advantageous to produce LEC in centralized labs and thereafter ship them to eye clinics. The present study used transport simulations of LEC to determine if vigorous shaking during transport altered the viability, morphology and phenotype during a 4 day-long storage of LEC with a previously described serum-free storage method. Inserts with LEC cultured on amniotic membranes were sutured to caps inside air-tight containers with generous amounts of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)-buffered minimal essential medium (MEM). The containers were distributed among the following testing conditions: 6 hours with full containers, 36 hours with full containers, 36 hours with container three quarters full of medium, and 36 hours with container full of medium containing a shear-protecting agent (Pluronic-F68). Compared to stored, but non-transported controls, no statistically significant changes in viability and immunohistochemical staining were observed. The epithelial sheets remained intact. However, an air-liquid interface in the containers reduced the number of desmosomes and hemi-desmosomes compared to the controls. In conclusion, cultured LEC sheets appear to endure vigorous shaking for at least 36 hours if the container is full.
Monocarboxylate transporter-1 promotes osteoblast differentiation via suppression of p53, a negative regulator of osteoblast differentiation
Authors: Sasa Kiyohito , Yoshimura Kentaro , Yamada Atsushi , Suzuki Dai , Miyamoto Yoichi , Imai Hiroko , Nagayama Kazuhiro , Maki Koutaro , Yamamoto Matsuo , Kamijo Ryutaro
Published: July 2018

Monocarboxylate transporter-1 (MCT-1) is a transmembrane transporter for monocarboxylates including lactate and pyruvate. Silencing Mct1 by its small interfering RNA (siRNA) suppressed the expression of marker genes for osteoblast differentiation, namely, Tnap, Runx2, and Sp7, induced by BMP-2 in mouse myoblastic C2C12 cells. Mct1 siRNA also suppressed alkaline phosphatase activity, as well as expressions of Tnap and Bglap mRNAs in mouse primary osteoblasts. On the other hand, Mct1 siRNA did not have effects on the Smad1/5 or ERK/JNK pathways in BMP-2-stimulated C2C12 cells, while it up-regulated the mRNA expression of p53 (Trp53) as well as nuclear accumulation of p53 in C2C12 cells in a BMP-2-independent manner. Suppression of osteoblastic differentiation by Mct1 siRNA in C2C12 cells was abolished by co-transfection of Trp53 siRNA. Together, these results suggest that MCT-1 functions as a positive regulator of osteoblast differentiation via suppression of p53.
Authentication of Garcinia fruits and food supplements using DNA barcoding and NMR spectroscopy
Authors: Seethapathy Gopalakrishnan Saroja , Tadesse Margey , Urumarudappa Santhosh Kumar J. , V. Gunaga Srikanth , Vasudeva Ramesh , Malterud Karl Egil , Shaanker Ramanan Uma , de Boer Hugo J. , Ravikanth Gudasalamani , Wangensteen Helle
Published: July 2018

Garcinia L. (Clusiaceae) fruits are a rich source of (−)-hydroxycitric acid, and this has gained considerable attention as an anti-obesity agent and a popular weight loss food supplement. In this study, we assessed adulteration of morphologically similar samples of Garcinia using DNA barcoding, and used NMR to quantify the content of (−)-hydroxycitric acid and (−)-hydroxycitric acid lactone in raw herbal drugs and Garcinia food supplements. DNA barcoding revealed that mostly G. gummi-gutta (previously known as G. cambogia) and G. indica were traded in Indian herbal markets, and there was no adulteration. The content of (−)-hydroxycitric acid and (−)-hydroxycitric acid lactone in the two species varied from 1.7% to 16.3%, and 3.5% to 20.7% respectively. Analysis of ten Garcinia food supplements revealed a large variation in the content of (−)-hydroxycitric acid, from 29 mg (4.6%) to 289 mg (50.6%) content per capsule or tablet. Only one product contained quantifiable amounts of (−)-hydroxycitric acid lactone. Furthermore the study demonstrates that DNA barcoding and NMR could be effectively used as a regulatory tool to authenticate Garcinia fruit rinds and food supplements.
Motor neuron development in zebrafish is altered by brief (5-hr) exposures to THC (∆9-tetrahydrocannabinol) or CBD (cannabidiol) during gastrulation
Authors: Ahmed Kazi T. , Amin Md Ruhul , Shah Parv , Ali Declan W.
Published: July 2018

Marijuana is one of the most commonly used illicit recreational drugs and is widely used for medicinal purposes. The psychoactive ingredient in marijuana is ∆9-tetrahydrocannabinol (∆9-THC), whereas the major non-psychoactive ingredient is cannabidiol (CBD). Here, we exposed zebrafish embryos to ∆9-THC or CBD for 5 hours during the critical stage of development known as gastrulation. Embryos were allowed to develop normally and were examined at 2 and 5 days post fertilization. THC and CBD treated embryos exhibited reduced heart rates, axial malformations and shorter trunks. Cannabinoid treatment altered synaptic activity at neuromuscular junctions (NMJs), and fluorescent labelling of primary and secondary motor neurons indicated a change in branching patterns and a reduction in the number of axonal branches in the trunk musculature. Furthermore, there were alterations in the α-bungarotoxin labelling of nicotinic acetylcholine receptors at NMJs. Locomotion studies show that larvae exposed to THC or CBD during gastrulation exhibited drastic reductions in the number of C-start escape responses to sound stimuli, but not to touch stimuli. Together these findings indicate that zebrafish embryos exposed to ∆9-THC or CBD during the brief but critical period of gastrulation exhibited alterations in heart rate, motor neuronal morphology, synaptic activity at the NMJ and locomotor responses to sound.
Functional brain networks reveal the existence of cognitive reserve and the interplay between network topology and dynamics
Authors: Martínez Johann H. , López María Eugenia , Ariza Pedro , Chavez Mario , Pineda-Pardo José A. , López-Sanz David , Gil Pedro , Maestú Fernando , Buldú Javier M.
Published: July 2018

We investigated how the organization of functional brain networks was related to cognitive reserve (CR) during a memory task in healthy aging. We obtained the magnetoencephalographic functional networks of 20 elders with a high or low CR level to analyse the differences at network features. We reported a negative correlation between synchronization of the whole network and CR, and observed differences both at the node and at the network level in: the average shortest path and the network outreach. Individuals with high CR required functional networks with lower links to successfully carry out the memory task. These results may indicate that those individuals with low CR level exhibited a dual pattern of compensation and network impairment, since their functioning was more energetically costly to perform the task as the high CR group. Additionally, we evaluated how the dynamical properties of the different brain regions were correlated to the network parameters obtaining that entropy was positively correlated with the strength and clustering coefficient, while complexity behaved conversely. Consequently, highly connected nodes of the functional networks showed a more stochastic and less complex signal. We consider that network approach may be a relevant tool to better understand brain functioning in aging.
Locally Gated SnS2/hBN Thin Film Transistors with a Broadband Photoresponse
Authors: Chu Dongil , Pak Sang Woo , Kim Eun Kyu
Published: July 2018

Next-generation flexible and transparent electronics demand newer materials with superior characteristics. Tin dichalcogenides, Sn(S,Se)2, are layered crystal materials that show promise for implementation in flexible electronics and optoelectronics. They have band gap energies that are dependent on their atomic layer number and selenium content. A variety of studies has focused in particular on tin disulfide (SnS2) channel transistors with conventional silicon substrates. However, the effort of interchanging the gate dielectric by utilizing high-quality hexagonal boron nitride (hBN) still remains. In this work, the hBN coupled SnS2 thin film transistors are demonstrated with bottom-gated device configuration. The electrical transport characteristics of the SnS2 channel transistor present a high current on/off ratio, reaching as high as 105 and a ten-fold enhancement in subthreshold swing compared to a high-κ dielectric covered device. We also demonstrate the spectral photoresponsivity from ultraviolet to infrared in a multi-layered SnS2 phototransistor. The device architecture is suitable to promote diverse studied on flexible and transparent thin film transistors for further applications.
Low-density lipoprotein (LDL)-dependent uptake of Gram-positive lipoteichoic acid and Gram-negative lipopolysaccharide occurs through LDL receptor
Authors: Grin Peter M. , Dwivedi Dhruva J. , Chathely Kevin M. , Trigatti Bernardo L. , Prat Annik , Seidah Nabil G. , Liaw Patricia C. , Fox-Robichaud Alison E.
Published: July 2018

Lipoteichoic acid (LTA) and lipopolysaccharide (LPS) are bacterial lipids that stimulate pro-inflammatory cytokine production, thereby exacerbating sepsis pathophysiology. Proprotein convertase subtilisin/kexin type 9 (PCSK9) negatively regulates uptake of cholesterol by downregulating hepatic lipoprotein receptors, including low-density lipoprotein (LDL) receptor (LDLR) and possibly LDLR-related protein-1 (LRP1). PCSK9 also negatively regulates Gram-negative LPS uptake by hepatocytes, however this mechanism is not completely characterized and mechanisms of Gram-positive LTA uptake are unknown. Therefore, our objective was to elucidate the mechanisms through which PCSK9 regulates uptake of LTA and LPS by investigating the roles of lipoproteins and lipoprotein receptors. Here we show that plasma PCSK9 concentrations increase transiently over time in septic and non-septic critically ill patients, with highly similar profiles over 14 days. Using flow cytometry, we demonstrate that PCSK9 negatively regulates LDLR-mediated uptake of LTA and LPS by HepG2 hepatocytes through an LDL-dependent mechanism, whereas LRP1 and high-density lipoprotein do not contribute to this uptake pathway. Bacterial lipid uptake by hepatocytes was not associated with cytokine production or hepatocellular injury. In conclusion, our study characterizes an LDL-dependent and LDLR-mediated bacterial lipid uptake pathway regulated by PCSK9, and provides evidence in support of PCSK9 inhibition as a potential therapeutic strategy for sepsis.
Transdermal optical imaging revealed different spatiotemporal patterns of facial cardiovascular activities
Authors: Liu Jiangang , Luo Hong , Zheng Paul Pu , Wu Si Jia , Lee Kang
Published: July 2018

Human cardiovascular activities are important indicators of a variety of physiological and psychological activities in human neuroscience research. The present proof-of-concept study aimed to reveal the spatiotemporal patterns of cardiovascular activities from the dynamic changes in hemoglobin concentrations in the face. We first recorded the dynamics of facial transdermal blood flow using a digital video camera and the Electrocardiography (ECG) signals using an ECG system simultaneously. Then we decomposed the video imaging data extracted from different sub-regions of a face into independent components using group independent component analysis (group ICA). Finally, the ICA components that included cardiovascular activities were identified by correlating their magnitude spectrum to those obtained from the ECG. We found that cardiovascular activities were associated with five independent components reflecting different spatiotemporal dynamics of facial blood flow changes. The strongest strengths of these ICA components were observed in the bilateral forehead, the left chin, and the left cheek, respectively. Our findings suggest that the cardiovascular activities presented different dynamic properties within different facial sub-regions, respectively. More broadly, the present findings point to the potential of the transdermal optical imaging technology as a new neuroscience methodology to study human physiology and psychology, noninvasively and remotely in a contactless manner.
Facile one-step synthesis of TiO2/Ag/SnO2 ternary heterostructures with enhanced visible light photocatalytic activity
Authors: Zhang Zewu , Ma Yuhang , Bu Xiaohai , Wu Qiong , Hang Zusheng , Dong Zhao , Wu Xiaohan
Published: July 2018

Novel TiO2/Ag/SnO2 composites were successfully prepared by a facile one-step reduction approach using stannous chloride as both SnO2 precursor and reducing agent. The Ag nanoparticles with sizes of 2.04–3.94 nm were located on TiO2 matrix and immobilized by the surrounded SnO2. The resulted TiO2/Ag/SnO2 nanocomposites were used as photocatalyst for photodegradation of methylene blue under visible light. The experimental results demonstrated that the visible light photocatalytic activity of the TiO2/Ag/SnO2 was significantly enhanced in comparison with the individual TiO2 or the binary composite (TiO2/Ag or TiO2/SnO2) and the degradation rate was up to about 9.5 times that of commercial TiO2. The photocatalytic activity of the TiO2/Ag/SnO2 composites could be well controlled by simply tuning the dosages of Ag precursor and the optimized activity of the composites was obtained when the dosage of Ag precursor was 2%. Moreover, the TiO2/Ag/SnO2 photocatalyst exhibited high stability for degradation of methylene blue even after four successive cycles.
Iron chelation increases the tolerance of Escherichia coli to hyper-replication stress
Authors: Charbon Godefroid , Klitgaard Rasmus N. , Liboriussen Charlotte Dahlmann , Thulstrup Peter Waaben , Maffioli Sonia Ilaria , Donadio Stefano , Løbner-Olesen Anders
Published: July 2018

In Escherichia coli, an increase in the frequency of chromosome replication is lethal. In order to identify compounds that affect chromosome replication, we screened for molecules capable of restoring the viability of hyper-replicating cells. We made use of two E. coli strains that over-initiate DNA replication by keeping the DnaA initiator protein in its active ATP bound state. While viable under anaerobic growth or when grown on poor media, these strains become inviable when grown in rich media. Extracts from actinomycetes strains were screened, leading to the identification of deferoxamine (DFO) as the active compound in one of them. We show that DFO does not affect chromosomal replication initiation and suggest that it was identified due to its ability to chelate cellular iron. This limits the formation of reactive oxygen species, reduce oxidative DNA damage and promote processivity of DNA replication. We argue that the benzazepine derivate (±)-6-Chloro-PB hydrobromide acts in a similar manner.
Magnetization reversal and interlayer exchange coupling in ferromagnetic metal/semiconductor Fe/GaMnAs hybrid bilayers
Authors: Tivakornsasithorn Kritsanu , Yoo Taehee , Lee Hakjoon , Lee Sangyeop , Choi Seonghoon , Bac Seul-Ki , Lee Kyung Jae , Lee Sanghoon , Liu Xinyu , Dobrowolska M. , Furdyna Jacek K.
Published: July 2018

We report a detailed study of magnetization reversal in Fe/GaMnAs bilayers carried out by magnetotransport measurements. Specifically, we have used planar Hall resistance (PHR), which is highly sensitive to the direction of magnetization, and is therefore ideally suited for tracking magnetization as it reorients between successive easy axes in the two magnetic layers during reversal. These reorientations take place separately in the two magnetic layers, resulting in a series of different magnetization alignments (parallel or orthogonal) during reversal, providing a series of stable PHR states. Our results indicate that the magnetic anisotropy of the structure is dominated by cubic symmetry of both layers, showing two in-plane easy axes, but with significantly different energy barriers between the easy orientations. Importantly, a careful analysis of the PHR results has also revealed the presence of strong ferromagnetic interlayer exchange coupling (IEC) between the two magnetic layers, indicating that although magnetization reorients separately in each layer, this process is not independent, since the behavior of one layer is influenced by its adjacent magnetic neighbor. The ability to design and realize multiple PHR states, as observed in this investigation, shows promise for engineering Fe/GaMnAs bilayer structures for multinary magnetic memory devices and related multinary logic elements.
Negligible contribution of M2634V substitution to ZIKV pathogenesis in AG6 mice revealed by a bacterial promoter activity reduced infectious clone
Authors: Zhao Fanfan , Xu Yongfen , Lavillette Dimitri , Zhong Jin , Zou Gang , Long Gang
Published: July 2018

ZIKV has emerged as a significant human pathogene for the severe neurological complications, including Guillain-Barré(GBS) syndrome in adults and a variety of fetal abnormalities such as microcephaly. A stable and efficient infectious clone of Brazilian ZIKV isolate is required to study pathogenesis of epidemic ZIKV and virus evolution impact on it. Here we successfully constructed infectious cDNA clone on an early Brazilian isolate by eliminating the activity of predicted bacterial promoter in 1–3000 nt of ZIKV genome, leading to a stable infectious cDNA clone (pZL1). pZL1 derived virus could infect different cell lines and cause lethal effect to AG6 mice. We further investigated the role of a recent emerged substitution in NS5 (M2634V). We found that a reverse mutation (V2634M) caused negligible effect on the ZIKV viral genome replication and infectious progeny production in multiple cell culture systems. Additionally, this mutation did not alter the pathogenesis feature and virulence of ZIKV in AG6 mice. In summary, our results present another robust infectious ZIKV clone from Brazilian isolate and provide evidences to support that M2634V single mutation did not alter virus life cycle in cell culture and pathogenesis in AG6 mouse model.
Allocation of forest biomass across broad precipitation gradients in China’s forests
Authors: Lie Zhiyang , Xue Li , Jacobs Douglass F.
Published: July 2018

Forests act as major sinks for atmospheric CO2. An understanding of the relationship between forest biomass allocation and precipitation gradients is needed to estimate the impacts of changes in precipitation on carbon stores. Biomass patterns depend on tree size or age, making it unclear whether biomass allocation is limited by tree age at regional scales. Using a dataset of ten typical forest types spanning a large age scale, we evaluated forest biomass allocation–precipitation correlations with the aim of testing whether biomass allocation patterns vary systematically in response to altered precipitation. With increasing mean annual precipitation, a significant quadratic increase occurred in ≤30 yr and >60 yr groups in stem biomass, >60 yr group in branch biomass, and >60 yr groups in leaf biomass; and a significant cubic increase occurred in 30–60 yr and all age forest groups in stem biomass, ≤30 yr, 30–60 yr and all age forest groups in branch biomass, ≤30 yr and all age forest groups in leaf biomass, and in each group in root biomass, indicating that organ biomass is strongly limited by precipitation. Thus, forest biomass responds predictably to changes in mean annual precipitation. The results suggest that forest organ biomass–precipitation relationships hold across independent datasets that encompass a broad climatic range and forest age.
Hypothermia ameliorates blast-related lifespan reduction of C. elegans
Authors: Angstman Nicholas B. , Frank Hans-Georg , Schmitz Christoph
Published: July 2018

Blast-related mild traumatic brain injury induces significant long-term health issues, yet treatment procedures remain underdeveloped. Therapeutic hypothermia has been postulated as a potentially effective therapy. In a Caenorhabditis elegans model, we demonstrate a dose-dependent reduction in lifespan following exposure to blast-like shock waves. Using polyvinyl alcohol, we show that cavitation is a key injurious factor in the damaging shock wave component. Short and long lifespan C. elegans mutants demonstrated the interaction of genetic and environmental longevity-determining factors. Hypothermia reduced the long term effect of shock wave exposure. Thus, we present an effective C. elegans model of long term effects of blast-related mild traumatic brain injury, as well as evidence of the merit of therapeutic hypothermia as a therapy option following blast exposure.