bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lightning Effects on the Grain Size Distribution of Volcanic Ash
Authors: Genareau K. , Wallace K. L. , Gharghabi P. , Gafford J. 
Published: March 2019

AbstractNatural volcanic ashfall samples were examined, and high‐current (~100 kA) electrical impulse experiments were conducted to reveal the changes in grain size that can occur during lightning discharge. Experiments on pseudo ash samples manufactured from volcanic deposits of both rhyolitic and basaltic composition show that aggregates of very fine grained ash particles (<32 μm) melt and degas to form vesiculated pumice fragments >100 μm in size. In some cases, bubbles <5 μm in diameter expand and detach from the outer surface of the pumice to form hollow spheres of glass, one type of lightning‐induced volcanic spherule, while other bubbles fragment. Volcanic ashfall from the 2009 Redoubt eruption and the 2016 Pavlof eruption contains both pumiceous grains and individual spherules. Results of this study reveal that volcanic lightning will alter the grain size distribution of ash through melting, vesiculation, and fragmentation of individual particles or ash aggregates.
The Effect of Mixed Wettability on Pore‐Scale Flow Regimes Based on a Flooding Experiment in Ketton Limestone
Authors: Rücker M. , Bartels W.‐B. , Singh K. , Brussee N. , Coorn A. , van der Linde H. A. , Bonnin A. , Ott H. , Hassanizadeh S. M. , Blunt M. J. , Mahani H. , Georgiadis A. , Berg S. 
Published: March 2019

AbstractDarcy‐scale multiphase flow in geological formations is significantly influenced by the wettability of the fluid‐solid system. So far it has not been understood how wettability impacts the pore‐scale flow regimes within rocks, which were in most cases regarded as an alteration from the base case of strongly water‐wet conditions by adjustment of contact angles. In this study, we directly image the pore‐scale flow regime in a carbonate altered to a mixed‐wet condition by aging with crude oil to represent the natural configuration in an oil reservoir with fast synchrotron‐based X‐ray computed tomography. We find that the pore‐scale flow regime is dominated by ganglion dynamics in which the pore space is intermittently filled with oil and brine. The frequency and size of these fluctuations are greater than in water‐wet rock such that their impact on the overall flow and relative permeability cannot be neglected in modeling approaches.
Liquid Iron Equation of State to the Terapascal Regime From Ab Initio Simulations
Authors: Wagle Fabian , Steinle‐Neumann Gerd 
Published: March 2019

AbstractWe present a thermodynamic model for liquid iron, based on ab initio molecular dynamics simulations, which is applicable to 2 TPa and beyond 10000 K, conditions that are relevant in the cores of super‐Earths. We combine ab initio results for V‐T‐P‐E with a correction scheme to match experimental properties at ambient pressure, where ab initio results show poor agreement. We explore the performance of our thermodynamic potential and various previously published models for liquid iron over a wide range of conditions: (i) at ambient pressure as a function of temperature, (ii) along the melting curve of Fe to 40 GPa, relevant for the cores of smaller terrestrial bodies in our solar system, (iii) along isentropes in the Earth's outer core, and (iv) for the core of super‐Earth Kepler‐36b. The correction term significantly improves the agreement of computed properties with experiments and other thermodynamic models that are based on an assessment of the phase diagram at ambient and moderate pressure, showing how ab initio molecular dynamics simulations can be used at par with other thermodynamic techniques. For the Earth's core, densities from the various models are similar, but higher‐order derivatives (acoustic velocities and Grüneisen parameter) show significant differences. Evaluated along a core‐temperature profile in Kepler‐36b, differences in density from various models are negligible, for core mass they do not exceed 2%, showing robust extrapolation of all equation of state models.
Transport of Radium and Nutrients Through Eastern South African Beaches
Authors: Moore Willard S. , Humphries Marc S. , Benitez‐Nelson Claudia R. , Pillay Letitia , Higgs Caldin 
Published: March 2019

AbstractSubmarine groundwater discharge (SGD) plays a critical role in coastal and ocean biogeochemistry. Elucidating spatially and temporally heterogeneous SGD fluxes is difficult. Here we use radium isotopes to explore the external sources and mixing regime along the eastern coast of South Africa. We demonstrate that the long‐lived radium isotope compositions are controlled by low inputs of low‐ and high‐salinity terrestrial groundwater. While activities of 228Ra and 226Ra in beach porewaters are similar to coastal waters, 224Ra is enriched by inputs of 228Th from coastal seawater. Porewater ages, based on the production of 224Ra from 228Th, range from 0.3 to 2.3 days, indicating rapid flushing of the beach system. Unlike radium, however, nutrients follow a more complex pathway. We hypothesize that high total dissolved nitrogen (TDN) and phosphorus concentrations in beach porewaters (TDN ranges from 1 to >700 μM) and the coastal ocean (TDN ranges from 1 to >40 μM) are derived from a source not enriched in radium. We speculate that this source is terrestrial water flowing below the dune barrier at depths exceeding our beach sampling depths. This water likely flows upward through breaches in the confining layer into the beach or enters the ocean directly through paleochannels. The presence of high nutrient concentrations in the coastal ocean unaccompanied by high 228Ra activities leads to the hypothesis of this additional nutrient source. These combined inputs may be of considerable importance to the coastal ecology of southeastern Africa, an oligotrophic ecosystem dominated by the nutrient‐poor Agulhas Current.
Temporally Constant Quaternary Uplift Rates and Their Relationship With Extensional Upper‐Plate Faults in South Crete (Greece), Constrained With36Cl Cosmogenic Exposure Dating
Authors: Robertson J. , Meschis M. , Roberts G. P. , Ganas A. , Gheorghiu D. M. 
Published: March 2019

AbstractPreserved sets of marine terraces and palaeoshorelines above subduction zones provide an opportunity to explore the long‐term deformation that occurs as a result of upper‐plate extension. We investigate uplifted palaeoshorelines along the South Central Crete Fault and over its western tip, located above the Hellenic Subduction Zone, in order to derive uplift rates and examine the role that known extensional faults contribute to observed coastal uplift. We have mapped palaeoshorelines and successfully dated four Late‐Quaternary wave‐cut platforms using in situ36Cl exposure dating. These absolute ages are used to guide a correlation of palaeoshorelines with Quaternary sea level highstands from 76.5 to ~900 ka; the results of which suggest that uplift rates vary along fault strikes but have been constant for up to 600 ka in places. Correlation of palaeoshorelines across the South Central Crete Fault results in a throw‐rate of 0.41 mm/year and, assuming repetition of 1.1‐m slip events, a fault‐specific earthquake recurrence interval of approximately 2,700 years. Elastic‐half‐space modeling implies that coastal uplift is related to offshore upper‐plate extensional faults. These faults may be responsible for perturbing the uplift rate signals in the south central Crete area. Our findings suggest that where uplifted marine terraces are used to make inferences about the mechanisms responsible for uplift throughout the Hellenic Subduction Zone, and other subduction zones worldwide, the impact of upper‐plate extensional faults over multiple seismic cycles should also be considered.
How Much Water Is Evaporated Across California? A Multiyear Assessment Using a Biophysical Model Forced With Satellite Remote Sensing Data
Authors: Baldocchi Dennis , Dralle David , Jiang Chongya , Ryu Youngryel 
Published: March 2019

AbstractCalifornia is expected to experience great spatial/temporal variations evaporation. These variations arise from strong north‐south, east‐west gradients in rainfall and vegetation, strong interannual variability in rainfall (±30%) and strong seasonal variability in the supply and demand for moisture. We used the Breathing Earth System Simulator to evaluate the rates and sums of evaporation across California, over the 2001–2017 period. Breathing Earth System Simulator is a bottom‐up, biophysical model that couples subroutines that calculate the surface energy balance, photosynthesis, and stomatal conductance. The model is forced with high‐resolution remote sensing data (1 km).The questions we address are as follows: How much water is evaporated across the natural and managed ecosystems of California? How much does evaporation vary during the booms and busts in annual rainfall? and Is evaporation increasing with time due to a warming climate? Mean annual evaporation, averaged over the 2001–2017 period, was relatively steady (393 ± 21 mm/year) given the high interannual variation in precipitation (519 ± 140 mm/year). No significant trend in evaporation at the statewide level was detected over this time period, despite a background of a warming climate. Irrigated agricultural crops and orchards, at 1‐km scale, use less water than inferred estimates for individual fields. This leaves the potential for sharing water, a scarce resource, more equitably among competing stakeholders, for example, farms, fish, people, and ecosystems.
A pediatric case of hypomagnesemia 1 (HOMG1) caused by novel compound heterozygous mutations in TRPM6
Authors: Goda Takeshi , Komatsu Hiroshi , Nozu Kandai , Nakajima Hisakazu 
Published: March 2019

AbstractHypomagnesemia 1 (HOMG1) is an extremely rare disease with autosomal recessive inheritance that is caused by mutations in the transient receptor potential melastatin 6 gene (TRPM6). Here, we describe a pediatric HOMG1 case with novel compound heterozygous mutations of TRPM6 (c.1483 C > T [p.Gln495*] and c.2715del [p.Trp905*]) in a 2-month-old boy who developed refractory seizures due to hypomagnesemia with secondary hypocalcemia.
Local unfolding of the HSP27 monomer regulates chaperone activity
Authors: Alderson T. Reid , Roche Julien , Gastall Heidi Y. , Dias David M. , Pritišanac Iva , Ying Jinfa , Bax Ad , Benesch Justin L. P. , Baldwin Andrew J. 
Published: March 2019

AbstractThe small heat-shock protein HSP27 is a redox-sensitive molecular chaperone that is expressed throughout the human body. Here, we describe redox-induced changes to the structure, dynamics, and function of HSP27 and its conserved α-crystallin domain (ACD). While HSP27 assembles into oligomers, we show that the monomers formed upon reduction are highly active chaperones in vitro, but are susceptible to self-aggregation. By using relaxation dispersion and high-pressure nuclear magnetic resonance (NMR) spectroscopy, we observe that the pair of β-strands that mediate dimerisation partially unfold in the monomer. We note that numerous HSP27 mutations associated with inherited neuropathies cluster to this dynamic region. High levels of sequence conservation in ACDs from mammalian sHSPs suggest that the exposed, disordered interface present in free monomers or oligomeric subunits may be a general, functional feature of sHSPs.
ABHD5 blunts the sensitivity of colorectal cancer to fluorouracil via promoting autophagic uracil yield
Authors: Ou Juanjuan , Peng Yuan , Yang Weiwen , Zhang Yue , Hao Jie , Li Fu , Chen Yanrong , Zhao Yang , Xie Xiong , Wu Shuang , Zha Lin , Luo Xi , Xie Ganfeng , Wang Liting , Sun Wei , Zhou Qi , Li Jianjun , Liang Houjie 
Published: March 2019

AbstractThe efficacy of Fluorouracil (FU) in the treatment of colorectal cancer (CRC) is greatly limited by drug resistance. Autophagy has been implicated in chemoresistance, but the role of selective autophagic degradation in regulating chemoresistance remains unknown. In this study, we revealed a critical role of ABHD5 in charging CRC sensitivity to FU via regulating autophagic uracil yield. We demonstrated that ABHD5 localizes to lysosome and interacts with PDIA5 to prevent PDIA5 from interacting with RNASET2 and inactivating RNASET2. ABHD5 deficiency releases PDIA5 to directly interact with RNASET2 and leave RNASET2 in an inactivate state, which impairs RNASET2-mediated autophagic uracil yield and promotes CRC cells to uptake FU as an exogenous uracil, thus increasing their sensitivity to FU. Our findings for the first time reveal a novel role of ABHD5 in regulating lysosome function, highlighting the significance of ABHD5 as a compelling biomarker predicting the sensitivity of CRCs to FU-based chemotherapy.
Ecological niche modelling does not support climatically-driven dinosaur diversity decline before the Cretaceous/Paleogene mass extinction
Authors: Chiarenza Alfio Alessandro , Mannion Philip D. , Lunt Daniel J. , Farnsworth Alex , Jones Lewis A. , Kelland Sarah-Jane , Allison Peter A. 
Published: March 2019

AbstractIn the lead-up to the Cretaceous/Paleogene mass extinction, dinosaur diversity is argued to have been either in long-term decline, or thriving until their sudden demise. The latest Cretaceous (Campanian–Maastrichtian [83–66 Ma]) of North America provides the best record to address this debate, but even here diversity reconstructions are biased by uneven sampling. Here we combine fossil occurrences with climatic and environmental modelling to quantify latest Cretaceous North American dinosaur habitat. Ecological niche modelling shows a Campanian-to-Maastrichtian habitability decrease in areas with present-day rock-outcrop. However, a continent-wide projection demonstrates habitat stability, or even a Campanian-to-Maastrichtian increase, that is not preserved. This reduction of the spatial sampling window resulted from formation of the proto-Rocky Mountains and sea-level regression. We suggest that Maastrichtian North American dinosaur diversity is therefore likely to be underestimated, with the apparent decline a product of sampling bias, and not due to a climatically-driven decrease in habitability as previously hypothesised.
Etv6 activates vegfa expression through positive and negative transcriptional regulatory networks in Xenopus embryos
Authors: Li Lei , Rispoli Rossella , Patient Roger , Ciau-Uitz Aldo , Porcher Catherine 
Published: March 2019

AbstractVEGFA signaling controls physiological and pathological angiogenesis and hematopoiesis. Although many context-dependent signaling pathways downstream of VEGFA have been uncovered, vegfa transcriptional regulation in vivo remains unclear. Here, we show that the ETS transcription factor, Etv6, positively regulates vegfa expression during Xenopus blood stem cell development through multiple transcriptional inputs. In agreement with its established repressive functions, Etv6 directly inhibits expression of the repressor foxo3, to prevent Foxo3 from binding to and repressing the vegfa promoter. Etv6 also directly activates expression of the activator klf4; reflecting a genome-wide paucity in ETS-binding motifs in Etv6 genomic targets, Klf4 then recruits Etv6 to the vegfa promoter to activate its expression. These two mechanisms (double negative gate and feed-forward loop) are classic features of gene regulatory networks specifying cell fates. Thus, Etv6’s dual function, as a transcriptional repressor and activator, controls a major signaling pathway involved in endothelial and blood development in vivo.
Drought and heat waves associated with climate change affect performance of the potato aphid Macrosiphum euphorbiae
Authors: Beetge Lezel , Krüger Kerstin 
Published: March 2019

AbstractThe combined effect of drought and heat waves on insect-plant interactions is complex and not fully understood. Insects may indirectly benefit from water-deficit stress through increased plant nitrogen levels. Heat stress may have a direct negative effect, yet insect performance may be improved when day-time heat is followed by cooler night temperatures. We show that moderate water-deficit stress (25–30% pot capacity) and high day-night temperatures (30/20 °C) affected Macrosiphum euphorbiae on potato (Solanum tuberosum) differently than their interactions. Water stress lowered stomatal conductance, and both water and heat stress reduced leaf area. The effect of water stress on nymphal and adult survival depended on temperature. Water stress added to reduced nymphal survival at high but not current (25/15 °C) day-night temperatures. Adult survival at high temperatures was reduced only when combined with water stress. Water stress and high temperatures independently but not interactively reduced the number of daily offspring. Moderate water stress when combined with high temperatures had a negative bottom-up effect on aphid survival even though lower night temperatures aided in the recovery from direct heat stress. Our study illustrates the importance of combining multiple stressors to better understand their impact on insect-plant interactions in the context of climate change.
Rotating magnetic field as tool for enhancing enzymes properties - laccase case study
Authors: Wasak Agata , Drozd Radosław , Jankowiak Dorota , Rakoczy Rafa 
Published: March 2019

AbstractThe aim of this study was to analyse the effect of rotating magnetic field (RMF) exposition on the fungal laccase catalytic properties. The results obtained in the study revealed that RMF may positively alter the laccase activity. A significant increase in activities of 11%, 11%, and 9% were observed at 10 Hz, 40 Hz and 50 Hz, respectively. Exposure of laccase to the rotating magnetic field resulted in its increased activity at broader pH range and a slight shift in optimum pH from 4.0 to 4.5 at RMF with frequency 20 Hz. The results show that the enzyme activity, stability, and optimum pH can be significantly altered depending on the characteristic of the applied RMF. Application of rotating magnetic field opens a new way for controlling and directions of enzyme-based bioprocessing.
Contribution to dose in healthy tissue from secondary target fragments in therapeutic proton, He and C beams measured with CR-39 plastic nuclear track detectors
Authors: Kodaira Satoshi , Kitamura Hisashi , Kurano Mieko , Kawashima Hajime , Benton Eric R. 
Published: March 2019

AbstractThe linear energy transfer (LET) spectrum, absorbed dose and dose equivalent from secondary particles of LET∞H2O ≥15 keV/μm deposited within the plateau of the Bragg curve in primary particle-induced nuclear target fragmentation reactions in tissue during proton and heavy ion radiotherapy were measured using CR-39 plastic nuclear track detectors and analyzed by means of atomic force microscopy. It was found that secondary target fragments contributed 20% to dose equivalent for primary protons (157 MeV), 13% for primary helium ions (145 MeV/n) and 4% for primary carbon ions (383 MeV/n), respectively. Little research has been done on the contribution from these particles to primary given dose. The smaller contribution measured for energetic carbon ion beams compared to proton beams can be considered an advantage of carbon ion radiotherapy over proton radiotherapy.
Effects of intercalated atoms on electronic structure of graphene nanoribbon/hexagonal boron nitride stacked layer
Authors: Sung Dongchul , Kim Gunn , Hong Suklyun 
Published: March 2019

AbstractUsing first-principles calculations, we investigate an atomic impurity at the interface of a van der Waals heterostructure (vdW heterostructure) consisting of a zigzag graphene nanoribbon (ZGNR) and a hexagonal boron nitride (h-BN) sheet. To find effects of atomic intercalation on geometrical and electronic properties of the ZGNR on the h-BN sheet, various types of impurity atoms are considered. The embedded atoms are initially placed at the edge or the middle of the ZGNR located on the h-BN sheet. Our results demonstrate that most of the impurity atoms are more stable at the edge than at the middle in all cases we consider. Especially, a nickel atom has the smallest energy difference (~0.15 eV) between the two embedding positions, which means that the Ni atom is relatively easy to intercalate in the structure. Finally, we discuss magnetic properties for the vdW heterostructure with an intercalated atom.
Notch Signaling Mediates Astrocyte Abnormality in Spinal Muscular Atrophy Model Systems
Authors: Ohuchi Kazuki , Funato Michinori , Yoshino Yuta , Ando Shiori , Inagaki Satoshi , Sato Arisu , Kawase Chizuru , Seki Junko , Saito Toshio , Nishio Hisahide , Nakamura Shinsuke , Shimazawa Masamitsu , Kaneko Hideo , Hara Hideaki 
Published: March 2019

AbstractSpinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterized by the degeneration of spinal motor neurons and muscle atrophy. The disease is mainly caused by low level of the survival motor neuron (SMN) protein, which is coded by two genes, namely SMN1 and SMN2, but leads to selective spinal motor neuron degeneration when SMN1 gene is deleted or mutated. Previous reports have shown that SMN-protein-deficient astrocytes are abnormally abundant in the spinal cords of SMA model mice. However, the mechanism of the SMN- deficient astrocyte abnormality remains unclear. The purpose of this study is to identify the cellular signaling pathways associated with the SMN-deficient astrocyte abnormality and propose a candidate therapy tool that modulates signaling. In the present study, we found that the astrocyte density was increased around the central canal of the spinal cord in a mouse SMA model and we identified the dysregulation of Notch signaling which is a known mechanism that regulates astrocyte differentiation and proliferation, in the spinal cord in both early and late stages of SMA pathogenesis. Moreover, pharmacological inhibition of Notch signaling improved the motor functional deficits in SMA model mice. These findings indicate that dysregulated Notch signaling may be an underlying cause of SMA pathology.
Microsatellite Borders and Micro-sequence Conservation in Juglans
Authors: Ebrahimi Aziz , Mathur Samarth , Lawson Shaneka S. , LaBonte Nicholas R. , Lorch Adam , Coggeshall Mark V. , Woeste Keith E. 
Published: March 2019

AbstractWalnuts (Juglans spp.) are economically important nut and timber species with a worldwide distribution. Using the published Persian walnut genome as a reference for the assembly of short reads from six Juglans species and several interspecific hybrids, we identified simple sequence repeats in 12 Juglans nuclear and organellar genomes. The genome-wide distribution and polymorphisms of nuclear and organellar microsatellites (SSRs) for most Juglans genomes have not been previously studied. We compared the frequency of nuclear SSR motifs and their lengths across Juglans, and identified section-specific chloroplast SSR motifs. Primer pairs were designed for more than 60,000 SSR-containing sequences based on alignment against assembled scaffold sequences. Of the >60,000 loci, 39,000 were validated by e-PCR using unique primer pairs. We identified primers containing 100% sequence identity in multiple species. Across species, sequence identity in the SSR-flanking regions was generally low. Although SSRs are common and highly dispersed in the genome, their flanking sequences are conserved at about 90 to 95% identity within Juglans and within species. In a few rare cases, flanking sequences are identical across species of Juglans. This comprehensive report of nuclear and organellar SSRs in Juglans and the generation of validated SSR primers will be a useful resource for future genetic analyses, walnut breeding programs, high-level taxonomic evaluations, and genomic studies in Juglandaceae.