bluuebunny/crossref_metadata_2025_split huggingface dataset:
Importance of Mountain Glaciers as a Source of Dissolved Organic Carbon
Authors: Li Xiangying , Ding Yongjian , Xu Jianzhong , He Xiaobo , Han Tianding , Kang Shichang , Wu Qingbai , Mika Sillanpää , Yu Zhongbo , Li Qijiang 
Published: June 2018

AbstractIce sheets and glaciers have been shown to deliver large amounts of labile dissolved organic carbon (DOC) to downstream aquatic ecosystems, but recent studies may underestimate the release of DOC from mountain glaciers. To date, continuous measurements of DOC from mountain glaciers throughout entire glacier melt season are very limited. Here we present high‐density data on DOC from two Asian mountain glaciers over a full melt season in 2013 and compile a global data set of DOC from 42 mountain glaciers. Based on our study and previously published DOC data, we estimate the storage and release of DOC associated with Asian mountain glaciers to be 8.8 to 13.8 Tg C and 0.19 Tg C/a, respectively. Rough extrapolation of glacier runoff to a global scale suggests that DOC release from mountain glaciers is on the order of 0.8 Tg C/a, which is 1.4 times higher than the most current estimates. The current release of DOC from mountain glaciers is therefore far more significant than previously thought and should be considered in future evaluation of the global carbon cycle.
Shear Rate‐Dependent Disequilibrium Rheology and Dynamics of Basalt Solidification
Authors: Kolzenburg S. , Giordano D. , Hess K. U. , Dingwell D. B. 
Published: June 2018

AbstractMagmas and lavas undergo a range of shear rates during transport and emplacement. Further, transport of magma and lava occurs at subliquidus conditions where the melt crystallizes at varying temperature, pressure, and oxygen fugacity. Transport efficiency and eruption style are governed by magma rheology, which evolves during cooling, crystallization and degassing. Quantification of magma rheology rests almost exclusively on experimentation at constant temperature and shear rate. We present the first study on the effect of shear rate on subliquidus basalt rheology at conditions relevant to lava flows and shallow magmatic systems. The results reveal that basalts reach their rheologic death or cutoff temperature (Tcutoff; i.e., the point at which the sample rheologically solidifies and flow stops) at higher temperatures when flowing faster, whereas crystallization is suppressed when the shear rate is low. We explore the implications of shear‐enhanced crystallization for modeling and forecasting of lava flow hazards and our understanding of magma and lava transport/storage systems.
Elastic Softening of (Mg0.8Fe0.2)O Ferropericlase Across the Iron Spin Crossover Measured at Seismic Frequencies
Authors: Marquardt H. , Buchen J. , Mendez A. S. J. , Kurnosov A. , Wendt M. , Rothkirch A. , Pennicard D. , Liermann H.‐P. 
Published: June 2018

AbstractWe experimentally determined the bulk modulus of (Mg0.8Fe0.2)O ferropericlase across the iron spin transition and in the low‐spin phase by employing a new experimental approach. In our measurements, we simulate the propagation of a compressional seismic wave (P wave) through our sample by employing a piezo‐driven dynamic diamond anvil cell that allows to oscillate pressure at seismic frequencies. During pressure oscillations, X‐ray diffraction images were continuously collected every 5–50 ms. The bulk modulus is directly calculated from these data at different pressures. Our experiments show a pronounced softening of the bulk modulus throughout the spin crossover, supporting previous single‐crystal measurements at very high frequencies and computations. Comparison of our results to previous data collected on (Mg,Fe)O with lower iron contents shows that the magnitude of softening strongly depends on iron content. Our experiments at seismic frequencies confirm that the iron spin crossover markedly affects the ratio of seismic compressional to shear wave velocities in Earth's lower mantle.
Ultralow Surface Temperatures in East Antarctica From Satellite Thermal Infrared Mapping: The Coldest Places on Earth
Authors: Scambos T. A. , Campbell G. G. , Pope A. , Haran T. , Muto A. , Lazzara M. , Reijmer C. H. , van den Broeke M. R. 
Published: June 2018

AbstractWe identify areas near the East Antarctic ice divide where <−90 °C surface snow temperatures are observed in wintertime satellite thermal‐band data under clear‐sky conditions. The lowest temperatures are found in small (<200 km2) topographic basins of ~2 m depth above 3,800 m elevation. Approximately 100 sites have observed minimum surface temperatures of ~−98 °C during the winters of 2004–2016. Comparisons of surface snow temperatures with near‐surface air temperatures at nearby weather stations indicate that ~−98 °C surfaces imply ~−94 ± 4 °C 2‐m air temperatures. Landsat 8 thermal band data and elevation data show gradients near the topographic depressions of ~6 °C km−1 horizontally and ~4 °C m−1 vertically. Ultralow temperature occurrences correlate with strong polar vortex circulation. We discuss a conceptual model of radiative surface cooling that produces an extreme inversion layer. Further cooling occurs as near‐surface cold air pools in shallow high‐elevation topographic basins, moderated by clear‐air downwelling radiation and heat from subsurface snow.
A Comparison of Model‐Based Ionospheric and Ocean Tidal Magnetic Signals With Observatory Data
Authors: Schnepf N. R. , Nair M. , Maute A. , Pedatella N. M. , Kuvshinov A. , Richmond A. D. 
Published: June 2018

AbstractObserved tidal geomagnetic field variations are due to a combination of electric currents in the ionosphere, ocean, and their induced counterparts. Using these variations to constrain subsurface electrical conductivity in oceanic regions is a promising frontier; however, properly separating the ionospheric and oceanic tidal contributions of the magnetic field is critical for this. We compare semidiurnal lunar tidal magnetic signals (i.e., the signals due to the M2 tidal mode) estimated from 64 global observatories to physics‐based forward models of the ionospheric M2 magnetic field and the oceanic M2 magnetic field. At ground level, predicted ionospheric M2 amplitudes are strongest in the horizontal components, whereas the predicted oceanic amplitudes are strongest in the vertical direction. There is good agreement between the predicted and estimated M2 phases for the Y component; however, the F and X components experience deviations that may be indicative of unmodeled ionospheric processes or unmodeled coastal effects. Overall, we find that the agreement between the physics‐based model predictions and the observations is very encouraging for electromagnetic sensing applications, especially since the predicted ionospheric vertical component is very weak.
Electron Flux Enhancements at L = 4.2 Observed by Global Positioning System Satellites: Relationship With Solar Wind and Geomagnetic Activity
Authors: Zhang Xiao‐Jia , Mourenas Didier , Artemyev Anton V. , Angelopoulos Vassilis , Thorne Richard Mansergh 
Published: June 2018

AbstractDetermining solar wind and geomagnetic activity parameters most favorable to strong electron flux enhancements is an important step toward forecasting radiation belt dynamics. Using electron flux measurements from Global Positioning System satellites at L = 4.2 in 2009–2016, we seek statistical relationships between flux enhancements at different energies and solar wind dynamic pressure Pdyn, AE, and Kp, from hundreds of events inside and outside the plasmasphere. Most ≥1‐MeV electron flux enhancements occur during nonstorm (or weak storm) times. Flux enhancements of 4‐MeV electrons outside the plasmasphere occur during periods of low Pdyn and high AE. We perform superposed epoch analyses of Global Positioning System electron fluxes, along with solar wind and geomagnetic indices, 40‐keV electron flux, ultralow frequency (ULF) wave index from Geostationary Operational Environmental Satellite, and chorus wave intensity from the Van Allen Probes and Time History of Events and Macroscale Interactions during Substorms mission. We demonstrate that 4‐MeV electron flux enhancements outside the plasmasphere start when the interplanetary magnetic field (Bz) reaches a minimum and develop during periods of low Pdyn, high AE, low but increasing Dst, moderate ULF wave index, and intense chorus waves. Flux enhancements at 100 keV occur under conditions with higher Pdyn, higher ULF wave index, and elevated 40‐keV electron flux at L = 6.6. Moreover, electron flux enhancements take much more time to develop at higher energies. This suggests that 100‐keV flux enhancements are dominated by injections, while MeV electron energization is predominantly induced by chorus waves with further amplification by inward transport.
Multi‐instrument Investigation of the Location of Saturn's Magnetotail X‐Line
Authors: Smith A. W. , Jackman C. M. , Thomsen M. F. , Lamy L. , Sergis N. 
Published: June 2018

AbstractReconnection is a fundamentally important process in planetary magnetospheres, with both local and global effects. At Saturn, observations of the magnetotail reconnection site (or x‐line) are rare, with only one in situ encounter reported to date. In this work, an extensive database of plasmoids and dipolarizations (Smith et al., 2016, https://doi.org/10.1002/2015JA022005) was investigated from a multi‐instrument perspective in order to probe the location and variability of the magnetotail x‐line. Several clear intervals were identified in which the x‐line location could be indirectly inferred to move on relatively short timescales. Two case studies are presented, the first of which concerns short‐lived flows, suggesting the reconnection sites can be either short‐lived (∼10 minutes) or extremely azimuthally limited (∼3RS/0.4 hr of local time). The second interval concerns the tailward motion of the reconnection site (or sites), inferred from the increasing electron temperature (and diminishing electron density) associated with the flows. This tailward motion occurs over ∼2.5 hr (approximately a quarter of a planetary rotation). The composition of the suprathermal plasma suggests that this could be an example of the gradual depletion of mass‐loaded flux tubes (that must occur prior to lobe reconnection). These case studies are consistent with previous statistical work that suggested that the site of reconnection in the Kronian magnetotail can be highly dynamic.
Role of Groundwater in the Dryland Ecohydrological System: A Case Study of the Heihe River Basin
Authors: Yao Yingying , Tian Yong , Andrews Charles , Li Xi , Zheng Yi , Zheng Chunmiao 
Published: June 2018

Key Points

Shallow groundwater (<10 m deep) of alluvial plain responds to land surface regimes and dominates seasonal water budget variations
Groundwater system in mountainous upstream impacts the evapotranspiration and surface‐groundwater interactions in alluvial plain downstream
Groundwater sustains ecosystem by contributing to evapotranspiration of vegetation in the growing season and buffering lateral flow
The independence of and associations among apoptosis, autophagy, and necrosis
Authors: Chen Qi , Kang Jian , Fu Caiyun 
Published: June 2018

AbstractCell death is an essential biological process for physiological growth and development. Three classical forms of cell death—apoptosis, autophagy, and necrosis—display distinct morphological features by activating specific signaling pathways. With recent research advances, we have started to appreciate that these cell death processes can cross-talk through interconnecting, even overlapping, signaling pathways, and the final cell fate is the result of the interplay of different cell death programs. This review provides an insight into the independence of and associations among these three types of cell death and explores the significance of cell death under the specific conditions of human diseases, particularly neurodegenerative diseases and cancer.
Targeting EZH2 reactivates a breast cancer subtype-specific anti-metastatic transcriptional program
Authors: Hirukawa Alison , Smith Harvey W. , Zuo Dongmei , Dufour Catherine R. , Savage Paul , Bertos Nicholas , Johnson Radia M. , Bui Tung , Bourque Guillaume , Basik Mark , Giguère Vincent , Park Morag , Muller William J. 
Published: June 2018

AbstractEmerging evidence has illustrated the importance of epigenomic reprogramming in cancer, with altered post-translational modifications of histones contributing to pathogenesis. However, the contributions of histone modifiers to breast cancer progression are unclear, and how these processes vary between molecular subtypes has yet to be adequately addressed. Here we report that genetic or pharmacological targeting of the epigenetic modifier Ezh2 dramatically hinders metastatic behaviour in both a mouse model of breast cancer and patient-derived xenografts reflective of the Luminal B subtype. We further define a subtype-specific molecular mechanism whereby EZH2 maintains H3K27me3-mediated repression of the FOXC1 gene, thereby inactivating a FOXC1-driven, anti-invasive transcriptional program. We demonstrate that higher FOXC1 is predictive of favourable outcome specifically in Luminal B breast cancer patients and establish the use of EZH2 methyltransferase inhibitors as a viable strategy to block metastasis in Luminal B breast cancer, where options for targeted therapy are limited.
One-second coherence for a single electron spin coupled to a multi-qubit nuclear-spin environment
Authors: Abobeih M. H. , Cramer J. , Bakker M. A. , Kalb N. , Markham M. , Twitchen D. J. , Taminiau T. H. 
Published: June 2018

AbstractSingle electron spins coupled to multiple nuclear spins provide promising multi-qubit registers for quantum sensing and quantum networks. The obtainable level of control is determined by how well the electron spin can be selectively coupled to, and decoupled from, the surrounding nuclear spins. Here we realize a coherence time exceeding a second for a single nitrogen-vacancy electron spin through decoupling sequences tailored to its microscopic nuclear-spin environment. First, we use the electron spin to probe the environment, which is accurately described by seven individual and six pairs of coupled carbon-13 spins. We develop initialization, control and readout of the carbon-13 pairs in order to directly reveal their atomic structure. We then exploit this knowledge to store quantum states in the electron spin for over a second by carefully avoiding unwanted interactions. These results provide a proof-of-principle for quantum sensing of complex multi-spin systems and an opportunity for multi-qubit quantum registers with long coherence times.
In vivo imaging of inflammation and oxidative stress in a nonhuman primate model of cardiac sympathetic neurodegeneration
Authors: Metzger Jeanette M. , Moore Colleen F. , Boettcher Carissa A. , Brunner Kevin G. , Fleddermann Rachel A. , Matsoff Helen N. , Resnikoff Henry A. , Bondarenko Viktoriya , Kamp Timothy J. , Hacker Timothy A. , Barnhart Todd E. , Lao Patrick J. , Christian Bradley T. , Nickles R. Jerry , Gallagher Catherine L. , Holden James E. , Emborg Marina E. 
Published: June 2018

AbstractLoss of cardiac postganglionic sympathetic innervation is a characteristic pathology of Parkinson’s disease (PD). It progresses over time independently of motor symptoms and is not responsive to typical anti-parkinsonian therapies. Cardiac sympathetic neurodegeneration can be mimicked in animals using systemic dosing of the neurotoxin 6-hydroxydopamine (6-OHDA). As in PD, 6-OHDA-induced neuronal loss is associated with increased inflammation and oxidative stress. To assess the feasibility of detecting changes over time in cardiac catecholaminergic innervation, inflammation, and oxidative stress, myocardial positron emission tomography with the radioligands [11C]meta-hydroxyephedrine (MHED), [11C]PBR28 (PBR28), and [61Cu]diacetyl-bis(N(4))-methylthiosemicarbazone (ATSM) was performed in 6-OHDA-intoxicated adult, male rhesus macaques (n = 10; 50 mg/kg i.v.). The peroxisome proliferator-activated receptor gamma (PPARγ) agonist pioglitazone, which is known to have anti-inflammatory and anti-oxidative stress properties, was administered to five animals (5 mg/kg, PO); the other five were placebo-treated. One week after 6-OHDA, cardiac MHED uptake was significantly reduced in both groups (placebo, 86% decrease; pioglitazone, 82%); PBR28 and ATSM uptake increased in both groups but were attenuated in pioglitazone-treated animals (PBR28 Treatment × Level ANOVAp < 0.002; ATSM Mann–Whitneyp = 0.032). At 12 weeks, partial recovery of MHED uptake was significantly greater in the pioglitazone-treated group, dependent on left ventricle circumferential region and axial level (Treatment × Region × Level ANOVAp = 0.034); 12-week MHED uptake significantly correlated with tyrosine hydroxylase immunoreactivity across cardiac anatomy (p < 0.000002). PBR28 and ATSM uptake returned to baseline levels by 12 weeks. These radioligands thus hold potential as in vivo biomarkers of mechanisms of cardiac neurodegeneration and neuroprotection.
Jia-Jian-Di-Huang-Yin-Zi decoction exerts neuroprotective effects on dopaminergic neurons and their microenvironment
Authors: Zhang Jingsi , Zhang Zhennian , Zhang Wen , Li Xiangting , Wu Ting , Li Tingting , Cai Min , Yu Zhonghai , Xiang Jun , Cai Dingfang 
Published: June 2018

AbstractAs a classical prescription of Traditional Chinese medicine, the Jia-Jian-Di-Huang-Yin-Zi (JJDHYZ) decoction has long been used to treat movement disorders. The present study evaluated the effects of JJDHYZ on dopaminergic (DA) neurons and their survival-enhancing microenvironment as well as the possible mechanisms involved using a mouse model of Parkinson’s disease. In MPTP-lesioned mice, a high dosage of JJDHYZ (34 g/kg/day) attenuated the loss of DA neurons, reversed the dopamine depletion, and improved the expression of glial-derived neurotrophic factor (GDNF) compared to the untreated model group. JJDHYZ also protected the ultrastructure of the blood-brain barrier (BBB) and tight junction proteins by inhibiting the activation of microglia and astrocytes besides the increase in three types of matrix metalloproteinases in the substantia nigra. In conclusion, the JJDHYZ-high dosage (JJDHYZ-H) group exhibited the neuroprotection of DA neurons, and the underlying mechanism may be related to the survival-enhancing microenvironment of the DA neurons.
Climate-induced shifts in leaf unfolding and frost risk of European trees and shrubs
Authors: Bigler Christof , Bugmann Harald 
Published: June 2018

AbstractClimate warming has advanced leaf unfolding of trees and shrubs, thus extending the growing period but potentially exposing plants to increased frost risk. The relative shifts in the timing of leaf unfolding vs. the timing and intensity of frost events determine whether frost risk changes under climate warming. Here we test whether the frost risk for unfolding leaves of 13 European tree and shrub species has changed over more than 60 years using dynamic state-space models and phenological observations from 264 sites located between 200 and 1900 m a.s.l. across Switzerland. Trees and shrubs currently feature sufficient safety margins regarding frost risk, which increase from early- to late-leafing species and tend to decrease with increasing elevation. Particularly after 1970 to 1990 and at higher elevations, leaf unfolding has advanced across all species. While the time between the last critical frost and leaf unfolding has shifted from predominantly positive trends in the late 1950s and 1960s to a trend reversal since the 2000s, the minimum temperature during leaf unfolding has mostly increased since the 1980s. These dynamic shifts in leaf unfolding and frost risk demonstrate species- and site-specific responses of trees and shrubs to climate cooling and warming.
Mechanistic insights into the augmented effect of bone marrow mesenchymal stem cells and thiazolidinediones in streptozotocin-nicotinamide induced diabetic rats
Authors: Hamza Alaaeldin Ahmed , Fikry Ebtehal Mohammad , Abdallah Wedad , Amin Amr 
Published: June 2018

AbstractThis study was designed to assess whether the protective effects of bone marrow-derived mesenchymal stem cells (MSCs) against diabetes could be enhanced by pioglitazone (PIO), a PPARγ agonist. Combined MSCs and PIO treatments markedly improved fasting blood glucose, body weight, lipid profile levels, insulin level, insulin resistance, β cell function. Those protective effects also attenuated both pancreatic lesions and fibrosis in diabetic rats and decreased the depletion of pancreatic mediators of glycemic and lipid metabolism including peroxisome proliferator-activated receptor alpha (PPARα), PGC-1α, GLP-1 and IRS-2. Cardiac biogenesis of diabetic groups was also improved with MSCs and/or PIO treatments as reflected by the enhanced up-regulation of the expressions of cardiac IRS1, Glucose transporter 4, PGC-1, PPARα and CPT-1 genes and the down-regulated expression of lipogenic gene SREBP. The combination of MSCs and PIO also potentiated the decrease of abnormal myocardial pathological lesions in diabetic rats. Similarly, the inhibitory effects of MSCs on diabetic cardiac fibrosis and on the up regulations of TGF-β, collagen I and III gene expressions were partial but additive when combined with PIO. Therefore, combined therapy with PIO and BMCs transplantation could further potentiate the protective benefit of MSCs against diabetes and cardiac damage compared to MSCs monotherapy.
Marine microalgae bioengineered Schizochytrium sp. meal hydrolysates inhibits acute inflammation
Authors: Wang Xiaoli , Wang Heng , Pierre Joseph F. , Wang Sheng , Huang Huifang , Zhang Jun , Liang Shuangzhen , Zeng Qingzhu , Zhang Chenqing , Huang Meijuan , Ruan Chengxu , Lin Juan , Li Hao 
Published: June 2018

AbstractBioengineered marine microalgae Schizochytrium sp. is currently used to produce docosahexaenoic acid (DHA). However, following DHA extraction, the remaining protein-rich materials are not well utilized. In this study, we report that marine microalgae bioengineered Schizochytrium sp. hydrolysate (MESH), which exhibits a unique peptide profile as identified by Ultra Performance Liquid Chromatography coupled with Q-TOF mass spectrometry(UPLC/Q-TOF-MS), ameliorated bowel inflammation in mice. In a mouse model of experimentalcolitis induced by dextran sulfate sodium, compared with the control mice, the mice treated with MESH were highly resistant to colitis, as demonstrated by marked reductions in body weight loss, clinical colitis scores, colonic histological damage, and colonic inflammation. Mechanistically, MESH attenuated the induction of pro-inflammatory cytokines and increased the induction of anti-inflammatory cytokines. MESH also promoted the proliferation of colonic crypt stem cells and progenitor cells required for crypt repair. Collectively, these results reveal a previously unrecognized role of MESH as a potential anti-inflammatory treatment for colitis.