bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructure of Cr-B Ohmic and Rectifying Contacts on (0001) 6H Sic
Authors: Liu R.-J. , Porter L. M. , Kim M. J. , Carpenter R. W. , Davis R. F. 
Published: May 2019

6H-SiC is a wide band-gap semiconductor. In recent years, a variety of high-power, -temperature, -speed and opto-electronic devices have been produced in 6H-SiC films. The future development of SiC device technology depends on the ability to form good ohmic and Schottky contacts. Plots of the current-voltage (I-V) characteristics of Cr-B contacts on (0001) 6H-SiC revealed that they became the most ohmic-like after annealing at 1000 °C for 240 sec. and rectifying after annealing for 300 sec, therefore TEM analysis of the microstructures of as-deposited and annealed Cr-B films should help in understanding what causes both the ohmic-like and rectifying behaviors.In this research, CrxBy film was deposited on vicinal (0001) 6H-SiC substrates by electron beam evaporation at room temperature. The intended phase was CrB2. Fig.l shows the microstructure of the as-deposited specimen. 6H-SiC appears to be a perfect crystal, but the Cr-B film had columnar polycrystalline microstructure.
Incorporation and harvest management of hairy vetch-based green manure influence nitrous oxide emissions
Authors: Kandel Tanka P. , Gowda Prasanna H. , Northup Brian K. , Rocateli Alexandre C. 
Published: May 2019

AbstractIn this study, we measured nitrous oxide (N2O) emissions from plots of fall-planted hairy vetch (HV, Vicia villosa) grown as a green nitrogen (N) source for following summer forage crabgrass (Digitaria sanguinalis). Two treatments were compared: (i) HV grown solely as green manure where all biomass was incorporated by tillage, and (ii) harvesting of aboveground HV biomass prior to planting of crabgrass. Fluxes of N2O were measured with closed chamber systems on 27 dates during a 2-month growth period of crabgrass after the termination of HV in early May. At termination, the average aboveground biomass yield of HV was 4.6 Mg ha−1 with 146 kg N ha−1 content. The N2O emissions were as high as 66 g N2O-N ha−1 day−1 on day 1 after HV incorporation, but reached close to zero within a week. Emissions of N2O increased with subsequent rainfall and irrigation events from both treatments but emission peaks were not observed during the rapid growth of crabgrass. Two-month cumulative emission of N2O (mean ± s.e., n = 4) from HV incorporated plots (921 ± 120 g N2O-N ha−1) was three times (P < 0.05) of HV harvested plots (326 ± 30 g N2O-N ha−1). However, crabgrass biomass yields, N concentrations and total biomass N uptake were decreased significantly by harvesting HV. In conclusion, the results suggested that whereas removal of HV biomass for use as forage may significantly reduce N2O emissions, quantity and quality of the following recipient crops may be constrained.
Multi‐Order Carbon Spectral Imager: A Sensor Concept for Carbon Cycle Investigations
Authors: Hall Jeffrey L. , Leifer Ira , Warren David W. , Hayhurst Thomas L. , Lampen Caleb P. , Tratt David M. 
Published: May 2019

AbstractDespite their importance to climate change, significant current and future source uncertainties remain for the most important carbon greenhouse gases (GHGs) methane (CH4) and carbon dioxide (CO2), particularly for the developing world. Mitigation by effective regulation and treaties requires accurate global GHG budgets, which only global‐scale (satellite) remote sensing can deliver. A high spatial and spectral resolution spectrometer is needed; herein, we present the design concept for a Multi‐Order Carbon Spectral Imager (MOCSI). MOCSI is designed for the global measurement of differential GHG column density and source fingerprinting from low Earth orbit. MOCSI includes three wavebands for CH4, CO2, and carbon monoxide (CO), whose altitude weighting functions emphasize the boundary layer, where the dominant GHG anthropogenic and natural sources are still unmixed and therefore most easily discerned against background levels. CO aids discrimination of megacity and fire GHG emissions from other sources and is also a precursor for ozone, which is also an important GHG. High spectral resolution ensures discrimination of target species from interferents, while high spatial resolution enhances sensitivity for discrete source identification and emission quantification. MOCSI is a compact, high‐throughput shortwave‐infrared pushbroom spectrometer that disperses multiple orders of a single grating onto a single focal plane array to minimize size, weight, and power of the instrument. MOCSI is specified to provide spatial and temporal resolution and sensitivity sufficient to address important global science questions related to megacity emissions, shifts in hydrocarbon production, and disaster response, as well as many others.
Origin of the Extended Mars Radar Blackout of September 2017
Authors: Sánchez–Cano Beatriz , Blelly Pierre‐Louis , Lester Mark , Witasse Olivier , Cartacci Marco , Orosei Roberto , Opgenoorth Hermann , Lillis Robert , Leblanc François , Milan Stephen E. , Conroy Philip , Floury Nicolas , Plane John M. C. , Cicchetti Andrea , Noschese Raffaella , Kopf Andrew J. 
Published: May 2019

AbstractThe Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) onboard Mars Express, which operates between 0.1 and 5.5 MHz, suffered from a complete blackout for 10 days in September 2017 when observing on the nightside (a rare occurrence). Moreover, the Shallow Radar (SHARAD) onboard the Mars Reconnaissance Orbiter, which operates at 20 MHz, also suffered a blackout for three days when operating on both dayside and nightside. We propose that these blackouts are caused by solar energetic particles of few tens of keV and above associated with an extreme space weather event between 10 and 22 September 2017, as recorded by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. Numerical simulations of energetic electron precipitation predict that a lower O2+ nighttime ionospheric layer of magnitude ~1010 m−3 peaking at ~90‐km altitude is produced. Consequently, such a layer would absorb radar signals at high frequencies and explain the blackouts. The peak absorption level is found to be at 70‐km altitude.
Evaluation of Machine Learning Classifiers for Predicting Deep Convection
Authors: Ukkonen Peter , Mäkelä Antti 
Published: May 2019

AbstractThe realistic representation of convection in atmospheric models is paramount for skillful predictions of hazardous weather as well as climate, yet climate models especially suffer from large uncertainties in the parameterization of clouds and convection. In this work, we examine the use of machine learning (ML) to predict the occurrence of deep convection from a state‐of‐the‐art atmospheric reanalysis (ERA5). Logistic regression, random forests, gradient‐boosted decision trees, and deep neural networks were trained with lightning data to predict thunderstorm occurrence (TO) in Central and Northern Europe (2012–2017) and in Sri Lanka (2016–2017). Up to 40 input variables were used, representing, for example, instability, humidity, and inhibition. Feature importances derived for the various models emphasize the high importance of conditional instability for deep convection in Europe, while in Sri Lanka, TO is more strongly regulated by humidity. The Precision‐Recall curve indicates more than a twofold improvement in skill over convective available potential energy for short‐term (0–45 min) predictions of TO in Europe by using neural networks or gradient‐boosted decision tree and a larger improvement in the tropical domain. The diurnal cycle of deep convection is closely reproduced, suggesting that ML could be used to trigger convection in climate models. Finally, a strong relationship was found between area‐mean monthly TO and ML predictions, with correlation coefficients exceeding 0.94 in all domains. Convective available potential energy has a similar level of correlation with monthly thunderstorm activity only in Northern Europe. The results encourage the use of reanalyses and ML to study climate trends in convective storms.
Observations and Modeling of a Hydrothermal Plume in Yellowstone Lake
Authors: Sohn Robert A. , Luttrell Karen , Shroyer Emily , Stranne Christian , Harris Robert N. , Favorito Julia E. 
Published: May 2019

AbstractAcoustic Doppler current profiler and conductivity‐temperature‐depth data acquired in Yellowstone Lake reveal the presence of a buoyant plume above the “Deep Hole” hydrothermal system, located southeast of Stevenson Island. Distributed venting in the ~200 × 200‐m hydrothermal field creates a plume with vertical velocities of ~10 cm/s in the mid‐water column. Salinity profiles indicate that during the period of strong summer stratification the plume rises to a neutral buoyancy horizon at ~45‐m depth, corresponding to a ~70‐m rise height, where it generates an anomaly of ~5% (−0.0014 psu) relative to background lake water. We simulate the plume with a numerical model and find that a heat flux of 28 MW reproduces the salinity and vertical velocity observations, corresponding to a mass flux of 1.4 × 103 kg/s. When observational uncertainties are considered, the heat flux could range between 20 to 50 MW.
Artificial neural networks enabled by nanophotonics
Authors: Zhang Qiming , Yu Haoyi , Barbiero Martina , Wang Baokai , Gu Min 
Published: May 2019

AbstractThe growing demands of brain science and artificial intelligence create an urgent need for the development of artificial neural networks (ANNs) that can mimic the structural, functional and biological features of human neural networks. Nanophotonics, which is the study of the behaviour of light and the light–matter interaction at the nanometre scale, has unveiled new phenomena and led to new applications beyond the diffraction limit of light. These emerging nanophotonic devices have enabled scientists to develop paradigm shifts of research into ANNs. In the present review, we summarise the recent progress in nanophotonics for emulating the structural, functional and biological features of ANNs, directly or indirectly.
Deianiraea, an extracellular bacterium associated with the ciliate Paramecium, suggests an alternative scenario for the evolution of Rickettsiales
Authors: Castelli Michele , Sabaneyeva Elena , Lanzoni Olivia , Lebedeva Natalia , Floriano Anna Maria , Gaiarsa Stefano , Benken Konstantin , Modeo Letizia , Bandi Claudio , Potekhin Alexey , Sassera Davide , Petroni Giulio 
Published: May 2019

Abstract
Rickettsiales are a lineage of obligate intracellular Alphaproteobacteria, encompassing important human pathogens, manipulators of host reproduction, and mutualists. Here we report the discovery of a novel Rickettsiales bacterium associated with Paramecium, displaying a unique extracellular lifestyle, including the ability to replicate outside host cells. Genomic analyses show that the bacterium possesses a higher capability to synthesise amino acids, compared to all investigated Rickettsiales. Considering these observations, phylogenetic and phylogenomic reconstructions, and re-evaluating the different means of interaction of Rickettsiales bacteria with eukaryotic cells, we propose an alternative scenario for the evolution of intracellularity in Rickettsiales. According to our reconstruction, the Rickettsiales ancestor would have been an extracellular and metabolically versatile bacterium, while obligate intracellularity would have evolved later, in parallel and independently, in different sub-lineages. The proposed new scenario could impact on the open debate on the lifestyle of the last common ancestor of mitochondria within Alphaproteobacteria.
Suppressing the Na+/H+ exchanger 1: a new sight to treat depression
Authors: Deng Xueyang , Ji Zhouye , Xu Bingru , Guo Liting , Xu Lixing , Qin Tingting , Feng Liang , Ma Zhanqiang , Fu Qiang , Qu Rong , Quo Qinglong , Ma Shiping 
Published: May 2019

AbstractNa+/H+ exchanger 1 (NHE1), an important regulator of intracellular pH (pHi) and extracellular pH (pHe), plays a crucial role in various physiological and pathological processes. However, the role of NHE1 in depression has not yet been reported. This study was designed to investigate the role of NHE1 in the animal model of depression and explore the underlying mechanisms. Our results showed that inhibition of rho-associated kinase 2 (ROCK2) by fasudil (Fas) or baicalin (BA) significantly alleviated chronic unpredictable mild stress (CUMS) paradigm-induced depression-related behaviours in mice, as shown by decreased sucrose consumption in sucrose preference test (SPT), reduced locomotor activity in the open field test (OFT), and increased immobility time in the tail suspension test (TST) and forced swimming test (FST). Furthermore, ROCK2 inhibition inhibited the activation of NHE1, calpain1, and reduced neuronal apoptosis in the CUMS animal model of depression. Next, we used the lipopolysaccharide (LPS)-challenged animal model of depression to induce NHE1 activation. Our results revealed that mice subjected to 1 μl LPS (10 mg/ml) injection intracerebroventricularly (i.c.v.) showed depressive-like behaviours and NHE1 activation. Amiloride (Ami), an NHE1 inhibitor, significantly reversed the decrease in sucrose consumption and reduction in immobility time in the TST and FST induced by LPS challenge. Furthermore, Ami decreased the expression of ROCK2, NHE1, calpain1, and caspase-3 and increased the Bcl-1/Bax ratio in the hippocampus of LPS-challenged mice. Ami treatment also led to antidepressive effects in the CUMS-induced animal model of depression. Thus ROCK2 inhibition could be proposed as a neuroprotective strategy against neuronal apoptosis, and NHE1 might be a potential therapeutic target in depression.
SREBP1 drives Keratin-80-dependent cytoskeletal changes and invasive behavior in endocrine-resistant ERα breast cancer
Authors: Perone Ylenia , Farrugia Aaron J. , Rodríguez-Meira Alba , Győrffy Balázs , Ion Charlotte , Uggetti Andrea , Chronopoulos Antonios , Marrazzo Pasquale , Faronato Monica , Shousha Sami , Davies Claire , Steel Jennifer H. , Patel Naina , del Rio Hernandez Armando , Coombes Charles , Pruneri Giancarlo , Lim Adrian , Calvo Fernando , Magnani Luca 
Published: May 2019

AbstractApproximately 30% of ERα breast cancer patients relapse with metastatic disease following adjuvant endocrine therapies. The connection between acquisition of drug resistance and invasive potential is poorly understood. In this study, we demonstrate that the type II keratin topological associating domain undergoes epigenetic reprogramming in aromatase inhibitors (AI)-resistant cells, leading to Keratin-80 (KRT80) upregulation. KRT80 expression is driven by de novo enhancer activation by sterol regulatory element-binding protein 1 (SREBP1). KRT80 upregulation directly promotes cytoskeletal rearrangements at the leading edge, increased focal adhesion and cellular stiffening, collectively promoting cancer cell invasion. Shearwave elasticity imaging performed on prospectively recruited patients confirms KRT80 levels correlate with stiffer tumors. Immunohistochemistry showed increased KRT80-positive cells at relapse and, using several clinical endpoints, KRT80 expression associates with poor survival. Collectively, our data uncover an unpredicted and potentially targetable direct link between epigenetic and cytoskeletal reprogramming promoting cell invasion in response to chronic AI treatment.
Maritime Continent water cycle regulates low-latitude chokepoint of global ocean circulation
Authors: Lee Tong , Fournier Séverine , Gordon Arnold L. , Sprintall Janet 
Published: May 2019

AbstractThe Maritime Continent (MC) is a low-latitude chokepoint of the world oceans with the Indonesian throughflow (ITF) linking the Indo-Pacific oceans, influencing global ocean circulation, climate, and biogeochemistry. While previous studies suggested that South-China-Sea freshwaters north of the MC intruding the Indonesian Seas weaken the ITF during boreal winter, the impact of the MC water cycle on the ITF has not been investigated. Here we use ocean-atmosphere-land satellite observations to reveal the dominant contribution of the MC monsoonal water cycle to boreal winter−spring freshening in the Java Sea through local precipitation and runoff from Kalimantan, Indonesia. We further demonstrate that the freshening corresponds to a reduced southward pressure gradient that would weaken the ITF. Therefore, the MC water cycle plays a critical role regulating ITF seasonality. The findings have strong implications to longer-term variations of the ITF associated with the variability and change of Indo-Pacific climate and MC water cycle.
Sox17 is required for endothelial regeneration following inflammation-induced vascular injury
Authors: Liu Menglin , Zhang Lianghui , Marsboom Glenn , Jambusaria Ankit , Xiong Shiqin , Toth Peter T. , Benevolenskaya Elizaveta V. , Rehman Jalees , Malik Asrar B. 
Published: May 2019

AbstractRepair of the endothelial cell barrier after inflammatory injury is essential for tissue fluid homeostasis and normalizing leukocyte transmigration. However, the mechanisms of endothelial regeneration remain poorly understood. Here we show that the endothelial and hematopoietic developmental transcription factor Sox17 promotes endothelial regeneration in the endotoxemia model of endothelial injury. Genetic lineage tracing studies demonstrate that the native endothelium itself serves as the primary source of endothelial cells repopulating the vessel wall following injury. We identify Sox17 as a key regulator of endothelial cell regeneration using endothelial-specific deletion and overexpression of Sox17. Endotoxemia upregulates Hypoxia inducible factor 1α, which in turn transcriptionally activates Sox17 expression. We observe that Sox17 increases endothelial cell proliferation via upregulation of Cyclin E1. Furthermore, endothelial-specific upregulation of Sox17 in vivo enhances lung endothelial regeneration. We conclude that endotoxemia adaptively activates Sox17 expression to mediate Cyclin E1-dependent endothelial cell regeneration and restore vascular homeostasis.
Initial state of DNA-Dye complex sets the stage for protein induced fluorescence modulation
Authors: Rashid Fahad , Raducanu Vlad-Stefan , Zaher Manal S. , Tehseen Muhammad , Habuchi Satoshi , Hamdan Samir M. 
Published: May 2019

AbstractProtein-induced fluorescence enhancement (PIFE) is a popular tool for characterizing protein-DNA interactions. PIFE has been explained by an increase in local viscosity due to the presence of the protein residues. This explanation, however, denies the opposite effect of fluorescence quenching. This work offers a perspective for understanding PIFE mechanism and reports the observation of a phenomenon that we name protein-induced fluorescence quenching (PIFQ), which exhibits an opposite effect to PIFE. A detailed characterization of these two fluorescence modulations reveals that the initial fluorescence state of the labeled mediator (DNA) determines whether this mediator-conjugated dye undergoes PIFE or PIFQ upon protein binding. This key role of the mediator DNA provides a protocol for the experimental design to obtain either PIFQ or PIFE, on-demand. This makes the arbitrary nature of the current experimental design obsolete, allowing for proper integration of both PIFE and PIFQ with existing bulk and single-molecule fluorescence techniques.
Femtosecond time-resolved two-photon photoemission studies of ultrafast carrier relaxation in Cu2O photoelectrodes
Authors: Borgwardt Mario , Omelchenko Stefan T. , Favaro Marco , Plate Paul , Höhn Christian , Abou-Ras Daniel , Schwarzburg Klaus , van de Krol Roel , Atwater Harry A. , Lewis Nathan S. , Eichberger Rainer , Friedrich Dennis 
Published: May 2019

AbstractCuprous oxide (Cu2O) is a promising material for solar-driven water splitting to produce hydrogen. However, the relatively small accessible photovoltage limits the development of efficient Cu2O based photocathodes. Here, femtosecond time-resolved two-photon photoemission spectroscopy has been used to probe the electronic structure and dynamics of photoexcited charge carriers at the Cu2O surface as well as the interface between Cu2O and a platinum (Pt) adlayer. By referencing ultrafast energy-resolved surface sensitive spectroscopy to bulk data we identify the full bulk to surface transport dynamics for excited electrons rapidly localized within an intrinsic deep continuous defect band ranging from the whole crystal volume to the surface. No evidence of bulk electrons reaching the surface at the conduction band level is found resulting into a substantial loss of their energy through ultrafast trapping. Our results uncover main factors limiting the energy conversion processes in Cu2O and provide guidance for future material development.
Publisher Correction: Multicolor multiscale brain imaging with chromatic multiphoton serial microscopy
Authors: Abdeladim Lamiae , Matho Katherine S. , Clavreul Solène , Mahou Pierre , Sintes Jean-Marc , Solinas Xavier , Arganda-Carreras Ignacio , Turney Stephen G. , Lichtman Jeff W. , Chessel Anatole , Bemelmans Alexis-Pierre , Loulier Karine , Supatto Willy , Livet Jean , Beaurepaire Emmanuel 
Published: May 2019

Affiliation 4 incorrectly read ‘University of the Basque Country (Ikerbasque), University of the Basque Country and Donostia International Physics Center, San Sebastian 20018, Spain.’Also, the affiliations of Ignacio Arganda-Carreras with ‘IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain’ and ‘Donostia International Physics Center (DIPC), San Sebastian, 20018, Spain’ were inadvertently omitted.Additionally, the third sentence of the first paragraph of the Results section entitled ‘Multicontrast organ-scale imaging with ChroMS microscopy’ incorrectly read ‘For example, one can choose lambda1 = 850 and lambda2 = 110 nm for optimal two-photon excitation of blue and red chromophores.’. The correct version reads ‘lambda2 = 1100 nm’ instead of ‘lambda2 = 110 nm’. These errors have now been corrected in the PDF and HTML versions of the Article.
A comparison of exercise interventions from bed rest studies for the prevention of musculoskeletal loss
Authors: Konda Nagarjun N. , Karri Rama S. , Winnard Andrew , Nasser Mona , Evetts Simon , Boudreau Eilis , Caplan Nick , Gradwell David , Velho Rochelle M. 
Published: May 2019

AbstractMusculoskeletal loss in actual or simulated microgravity occurs at a high rate. Bed rest studies are a reliable ground-based spaceflight analogue that allow for direct comparison of intervention and control participants. The aim of this review was to investigate the impact of exercise compared to no intervention on bone mineral density (BMD) and muscle cross-sectional area (muscle CSA) in bed rest studies relative to other terrestrial models. Eligible bed rest studies with healthy participants had an intervention arm with an exercise countermeasure and a control arm. A search strategy was implemented for MEDLINE. After screening, eight studies were identified for inclusion. Interventions included resistive exercise (RE), resistive vibration exercise (RVE), flywheel resistive exercise, treadmill exercise with lower body negative pressure (LBNP) and a zero-gravity locomotion simulator (ZLS). Lower limb skeletal sites had the most significant BMD losses, particularly at the hip which reduced in density by 4.59% (p < 0.05) and the tibial epiphysis by 6% (p < 0.05). Exercise attenuated bone loss at the hip and distal tibia compared to controls (p < 0.05). Muscle CSA changes indicated that the calf and quadriceps were most affected by bed rest. Exercise interventions significantly attenuated loss of muscle mass. ZLS, LBNP treadmill and RE significantly attenuated bone and muscle loss at the hip compared to baseline and controls. Despite exercise intervention, high rates of bone loss were still observed. Future studies should consider adding bisphosphonates and pharmacological/nutrition-based interventions for consideration of longer-duration missions. These findings correlate to terrestrial bed rest settings, for example, stroke or spinal-injury patients.