bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histamine-2 receptor antagonist famotidine modulates cardiac stem cell characteristics in hypertensive heart disease
Authors: Saheera Sherin , Potnuri Ajay G. , Nair Renuka 
Published: October 2017

Background
Cardiac stem cells (CSCs) play a vital role in cardiac homeostasis. A decrease in the efficiency of cardiac stem cells is speculated in various cardiac abnormalities. The maintenance of a healthy stem cell population is essential for the prevention of adverse cardiac remodeling leading to cardiac failure. Famotidine, a histamine-2 receptor antagonist, is currently used to treat ulcers of the stomach and intestines. In repurposing the use of the drug, reduction of cardiac hypertrophy and improvement in cardiac function of spontaneously hypertensive rats (SHR) was reported by our group. Given that stem cells are affected in cardiac pathologies, the effect of histamine-2 receptor antagonism on CSC characteristics was investigated.

Methods
To examine whether famotidine has a positive effect on CSCs, spontaneously hypertensive rats (SHR) treated with the drug were sacrificed; and CSCs isolated from atrial appendages was evaluated. Six-month-old male SHRs were treated with famotidine (30 mg/kg/day) for two months. The effect of famotidine treatment on migration, proliferation and survival of CSCs was compared with untreated SHRs and normotensive Wistar rats.

Results
Functional efficiency of CSCs from SHR was compromised relative to that in Wistar rat. Famotidine increased the migration and proliferation potential, along with retention of stemness of CSCs in treated SHRs. Cellular senescence and oxidative stress were also reduced. The expression of H2R was unaffected by the treatment.

Discussion
As anticipated, CSCs from SHRs were functionally impaired. Stem cell attributes of famotidine-treated SHRs was comparable to that of Wistar rats. Therefore, in addition to being cardioprotective, the histamine 2 receptor antagonist modulated cardiac stem cells characteristics. Restoration of stem cell efficiency by famotidine is possibly mediated by reduction of oxidative stress as the expression of H2R was unaffected by the treatment. Maintenance of healthy stem cell population is suggested as a possible mechanism underlying the cardioprotective effect of famotidine.
Design of Remediation Actions for Nutrient Mitigation in the Hyporheic Zone
Authors: Morén I. , Wörman A. , Riml J. 
Published: October 2017

AbstractAlthough hyporheic exchange has been shown to be of great importance for the overall water quality of streams, it is rarely considered quantitatively in stream remediation projects. A main driver of hyporheic exchange is the hydraulic head fluctuation along the streambed, which can be enhanced by modifications of the streambed topography. Here we present an analytical 2‐D spectral subsurface flow model to estimate the hyporheic exchange associated with streambed topographies over a wide range of spatial scales; a model that was validated using tracer‐test‐results and measurements of hydraulic conductivity. Specifically, engineered steps in the stream were shown to induce a larger hyporheic exchange velocity and shorter hyporheic residence times compared to the observed topography in Tullstorps Brook, Sweden. Hyporheic properties were used to parameterize a longitudinal transport model that accounted for reactions in terms of first‐order decay and instantaneous adsorption. Theoretical analyses of the mitigation effect for nitrate due to denitrification in the hyporheic zone show that there is a Damköhler number of the hyporheic zone, associated with several different stream geomorphologies, that optimizes nitrate mass removal on stream reach scale. This optimum can be limited by the available hydraulic head gradient given by the slope of the stream and the geological constraints of the streambed. The model illustrates the complex interactions between design strategies for nutrient mitigation, hyporheic flow patterns, and stream biogeochemistry and highlights the importance to diagnose a stream prior remediation, specifically to evaluate if remediation targets are transport or reaction controlled.
Evaluating the Effects of Tracer Choice and End‐Member Definitions on Hydrograph Separation Results Across Nested, Seasonally Cold Watersheds
Authors: Bansah Samuel , Ali Genevieve 
Published: October 2017

AbstractIsotope‐based hydrograph separation (IHS) is a widely used method in studies of runoff generation and streamflow partitioning. Challenges in choosing and characterizing appropriate tracers and end‐members have, however led to presumably highly uncertain IHS results. Here we tested the effects of end‐member definitions and tracer choices on IHS results in nested Prairie watersheds of varying size and landscape characteristics. Specifically, the consideration of eight potential “new” water end‐members, eight potential “old” water end‐members, and two stable water isotope tracers led to 80 potential IHS results for each stream water sample. IHS‐related uncertainty was evaluated using a Gaussian error propagation method. Results show that choosing an appropriate “new” water end‐member is most challenging during the freshet: highly variable “old” water fractions associated with high uncertainties were attributed to changing conditions from melting snow only to rain‐on‐snow. In summer and fall, it was rather the choice of an appropriate “old” water end‐member that was most problematic. IHS results obtained using δ18O versus δ2H as a tracer were significantly different except in the flattest and most wind‐sheltered watersheds examined. Overall, δ2H‐based IHS results were more uncertain than their δ18O‐based counterparts. Recommendations are therefore made toward careful selection of a tracer and a sampling strategy aimed at characterizing the most appropriate end‐members for IHS, especially when dealing with seasonally cold watersheds.
Phase Relations in the System MgSiO3‐Al2O3 up to 2300 K at Lower Mantle Pressures
Authors: Liu Zhaodong , Nishi Masayuki , Ishii Takayuki , Fei Hongzhan , Miyajima Nobuyoshi , Ballaran Tiziana Boffa , Ohfuji Hiroaki , Sakai Takeshi , Wang Lin , Shcheka Svyatoslav , Arimoto Takeshi , Tange Yoshinori , Higo Yuji , Irifune Tetsuo , Katsura Tomoo 
Published: October 2017

AbstractPhase relations in the system MgSiO3‐Al2O3 were investigated at pressures of 27–45 GPa and temperatures of 1700, 2000, and 2300 K using sintered diamond and tungsten carbide anvils in a multianvil apparatus. The bulk compositions in the MgSiO3‐Al2O3 binary system crystallize a phase assemblage of pyrope and corundum at pressures below 27 GPa and an assemblage of bridgmanite and corundum at pressures above 27 GPa regardless of temperatures. The solubility of Al2O3 in bridgmanite and that of MgSiO3 in corundum increases significantly with increasing temperature. The solubility of Al2O3 in bridgmanite increases from 6.7 mol % at 1700 K to 21.8 mol % at 2500 K under a constant pressure of 27 GPa. Bridgmanite becomes more aluminous with increasing pressure from 27 to 45 GPa at a given temperature. The MgSiO3 content in corundum increases with increasing pressure at pressure lower than 27 GPa, while it decreases at pressure higher than 27 GPa. Our results suggest that bridgmanite can incorporate a considerably higher Al2O3 content than that of the pyrope composition (25 mol % Al2O3). The present study further suggests that the entire Al2O3 component is accommodated into bridgmanite in the pyrolite lower mantle. However, Al2O3 cannot be fully accommodated into bridgmanite in the coldest parts of subducted slabs in the shallow part of the lower mantle, and therefore, additional phases such as MgAl2O4 with calcium ferrite‐type structure are necessary to host the excess Al2O3.
Spatiotemporal Variation of Stress Drop During the 2008 Mogul, Nevada, Earthquake Swarm
Authors: Ruhl C. J. , Abercrombie R. E. , Smith K. D. 
Published: October 2017

AbstractWe estimate stress drops for 148 shallow (<6 km) earthquakes in the complex 2008 Mogul, Nevada, swarm using empirical Green's function‐derived spectral ratios. Near‐source, temporary broadband seismometers deployed before theMw4.9 main shock provide high‐quality records of many foreshocks and aftershocks, and an ideal opportunity to investigate uncertainties in corner frequency measurement as well as stress drop (Δσ) variation related to space, time, depth, mechanism, and magnitude. We explore uncertainties related to source model, measurement approach, cross‐correlation limit, and frequency bandwidth.P(S) wave Δσresults range from 0.2 ± 0.15 (0.3 ± 0.15) to 36±20 (58±7) MPa, a variation greater than the error range of each individual estimate. Although this variation is not explained simply by any one parameter, spatiotemporal variation along the main shock fault plane is distinct: coherent clusters of high and low Δσearthquakes are seen, and high‐Δσforeshocks correlate with an area of reduced aftershock productivity. These observations are best explained by a difference in rheology along the fault plane. Average Δσs of 3.9±1.1 (4.0±1.1) MPa usingP(S) are similar to those found for earthquakes in a variety of settings, implying that these shallow, potentially fluid‐driven earthquakes do not have systematically lower Δσthan average tectonic earthquakes (~4 MPa) and, therefore, have similar (or higher, due to proximity to the surface) expected ground motions compared to typical earthquakes. The unprecedented detail achieved for these shallow, small‐magnitude earthquakes confirms that Δσ, when measured precisely, is a valuable observation of physically meaningful fault zone properties and earthquake behavior.
Modeling Forced Imbibition Processes and the Associated Seismic Attenuation in Heterogeneous Porous Rocks
Authors: Solazzi Santiago G. , Guarracino Luis , Rubino J. Germán , Müller Tobias M. , Holliger Klaus 
Published: October 2017

AbstractQuantifying seismic attenuation during laboratory imbibition experiments can provide useful information toward the use of seismic waves for monitoring injection and extraction of fluids in the Earth's crust. However, a deeper understanding of the physical causes producing the observed attenuation is needed for this purpose. In this work, we analyze seismic attenuation due to mesoscopic wave‐induced fluid flow (WIFF) produced by realistic fluid distributions representative of imbibition experiments. To do so, we first perform two‐phase flow simulations in a heterogeneous rock sample to emulate a forced imbibition experiment. We then select a subsample of the considered rock containing the resulting time‐dependent saturation fields and apply a numerical upscaling procedure to compute the associated seismic attenuation. By exploring both saturation distributions and seismic attenuation, we observe that two manifestations of WIFF arise during imbibition experiments: the first one is produced by the compressibility contrast associated with the saturation front, whereas the second one is due to the presence of patches containing very high amounts of water that are located behind the saturation front. We demonstrate that while the former process is expected to play a significant role in the case of high injection rates, which are associated with viscous‐dominated imbibition processes, the latter becomes predominant during capillary‐dominated processes, that is, for relatively low injection rates. We conclude that this kind of joint numerical analysis constitutes a useful tool for improving our understanding of the physical mechanisms producing seismic attenuation during laboratory imbibition experiments.
Reservoir Structure and Wastewater‐Induced Seismicity at the Val d'Agri Oilfield (Italy) Shown by Three‐Dimensional Vp and Vp/Vs Local Earthquake Tomography
Authors: Improta L. , Bagh S. , De Gori P. , Valoroso L. , Pastori M. , Piccinini D. , Chiarabba C. , Anselmi M. , Buttinelli M. 
Published: October 2017

AbstractWastewater injection into a high‐rate well in the Val d'Agri oilfield, the largest in onshore Europe, has induced swarm microseismicity since the initiation of disposal in 2006. To investigate the reservoir structure and to track seismicity, we performed a high‐spatial resolution local earthquake tomography using 1,281 natural and induced earthquakes recorded by local networks. The properties of the carbonate reservoir (rock fracturing, pore fluid pressure) and inherited faults control the occurrence and spatiotemporal distribution of seismicity. A low‐Vp, high‐Vp/Vs region under the well represents a fluid saturated fault zone ruptured by induced seismicity. High‐Vp, high‐Vp/Vs bumps match reservoir culminations indicating saturated liquid‐bearing zones, whereas a very low Vp, low Vp/Vs anomaly might represent a strongly fractured and depleted zone of the hydrocarbon reservoir characterized by significant fluid withdrawal. The comprehensive picture of the injection‐linked seismicity obtained by integrating reservoir‐scale tomography, high‐precision earthquake locations, and geophysical and injection data suggests that the driving mechanism is the channeling of pore pressure perturbations through a high permeable fault damage zone within the reservoir. The damage zone surrounds a Pliocene reverse fault optimally oriented in the current extensional stress field. The ruptured damage zone measures 2 km along strike and 3 km along dip and is confined between low permeability ductile formations. Injection pressure is the primary parameter controlling seismicity rate. Our study underlines that local earthquake tomography also using wastewater‐induced seismicity can give useful insights into the physical mechanism leading to these earthquakes.
Comprehensive Analysis of Traveltime Data Collected Through GPS‐Acoustic Observation of Seafloor Crustal Movements
Authors: Honsho Chie , Kido Motoyuki 
Published: October 2017

AbstractWe have developed a comprehensive inversion scheme to analyze traveltime data collected through GPS‐acoustic observations on a campaign basis. Our method uses a quantity called the “nadir total delay” (NTD), which is analogous to the zenith total delay in Global Navigation Satellite Systems analyses, to represent the time variation of the sound speed. The observation equation using the NTD is an approximated formulation. We examine its applicable scope using numerical experiments and demonstrate that the approximation holds well enough in practice. Traveltime data from all our observation campaigns were utilized together for inversion calculation to determine the following: (1) the positions of individual precision acoustic transponders at the time of a particular reference campaign, (2) the displacement from these positions of a rigid array at the time of each campaign, and (3) the time variation of the NTD during each campaign. We applied this method to actual data to fix the array geometry more precisely. Also, we have made a first step in detecting vertical motions as well as horizontal motions, though further enhancement of the accuracy will be required. In performing linear regression of array displacements obtained from the inversion, their error covariance has a significant effect on the resulting velocities. When the covariance is taken into account, nearly the same velocities are obtained no matter what campaign is taken as reference in the inversion.
Impact of In‐Cloud Aqueous Processes on the Chemistry and Transport of Biogenic Volatile Organic Compounds
Authors: Li Yang , Barth Mary C. , Patton Edward G. , Steiner Allison L. 
Published: October 2017

AbstractWe investigate the impacts of cloud aqueous processes on the chemistry and transport of biogenic volatile organic compounds (BVOC) using the National Center for Atmospheric Research's large‐eddy simulation code with an updated chemical mechanism that includes both gas‐ and aqueous‐phase reactions. We simulate transport and chemistry for a meteorological case with a diurnal pattern of nonprecipitating cumulus clouds from the Baltimore‐Washington area DISCOVER‐AQ campaign. We evaluate two scenarios with and without aqueous‐phase chemical reactions. In the cloud layer (2–3 km), the addition of aqueous phase reactions decreases HCHO by 18% over the domain due to its solubility and the fast depletion from aqueous reactions, resulting in a corresponding decrease in radical oxidants (e.g., 18% decrease in OH). The decrease of OH increases the mixing ratios of isoprene and methacrolein (MACR) (100% and 15%, respectively) in the cloud layer because the reaction rate is lower. Aqueous‐phase reactions can modify the segregation between OH and BVOC by changing the sign of the segregation intensity, causing up to 55% reduction in the isoprene‐OH reaction rate and 40% reduction for the MACR‐OH reaction when clouds are present. Analysis of the isoprene‐OH covariance budget shows the chemistry term is the primary driver of the strong segregation in clouds, triggered by the decrease in OH. All organic acids except acetic acid are formed only through aqueous‐phase reactions. For acids formed in the aqueous phase, turbulence mixes these compounds on short time scales, with the near‐surface mixing ratios of these acids reaching 20% of the mixing ratios in the cloud layer within 1 h of cloud formation.
Does Strong Tropospheric Forcing Cause Large‐Amplitude Mesospheric Gravity Waves? A DEEPWAVE Case Study
Authors: Bramberger Martina , Dörnbrack Andreas , Bossert Katrina , Ehard Benedikt , Fritts David C. , Kaifler Bernd , Mallaun Christian , Orr Andrew , Pautet P.‐Dominique , Rapp Markus , Taylor Michael J. , Vosper Simon , Williams Bifford P. , Witschas Benjamin 
Published: October 2017

AbstractOn 4 July 2014, during the Deep Propagating Gravity Wave Experiment (DEEPWAVE), strong low‐level horizontal winds of up to 35 m s−1 over the Southern Alps, New Zealand, caused the excitation of gravity waves having the largest vertical energy fluxes of the whole campaign (38 W m−2). At the same time, large‐amplitude mesospheric gravity waves were detected by the Temperature Lidar for Middle Atmospheric Research (TELMA) located at Lauder (45.0°S, 169.7°E), New Zealand. The coincidence of these two events leads to the question of whether the mesospheric gravity waves were generated by the strong tropospheric forcing. To answer this, an extensive data set is analyzed, comprising TELMA, in situ aircraft measurements, radiosondes, wind lidar measurements aboard the DLR Falcon as well as Rayleigh lidar and advanced mesospheric temperature mapper measurements aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V. These measurements are further complemented by limited area simulations using a numerical weather prediction model. This unique data set confirms that strong tropospheric forcing can cause large‐amplitude gravity waves in the mesosphere, and that three essential ingredients are required to achieve this: first, nearly linear propagation across the tropopause; second, leakage through the stratospheric wind minimum; and third, amplification in the polar night jet. Stationary gravity waves were detected in all atmospheric layers up to the mesosphere with horizontal wavelengths between 20 and 100 km. The complete coverage of our data set from troposphere to mesosphere proved to be valuable to identify the processes involved in deep gravity wave propagation.
Verification of Space Weather Forecasts Issued by the Met Office Space Weather Operations Centre
Authors: Sharpe M. A. , Murray S. A. 
Published: October 2017

AbstractThe Met Office Space Weather Operations Centre was founded in 2014 and part of its remit is a daily Space Weather Technical Forecast to help the UK build resilience to space weather impacts; guidance includes 4 day geomagnetic storm forecasts (GMSF) and X‐ray flare forecasts (XRFF). It is crucial for forecasters, users, modelers, and stakeholders to understand the strengths and weaknesses of these forecasts; therefore, it is important to verify against the most reliable truth data source available. The present study contains verification results for XRFFs using Geo‐Orbiting Earth Satellite 15 satellite data and GMSF using planetary K‐index (Kp) values from the GFZ Helmholtz Centre. To assess the value of the verification results, it is helpful to compare them against a reference forecast and the frequency of occurrence during a rolling prediction period is used for this purpose. An analysis of the rolling 12 month performance over a 19 month period suggests that both the XRFF and GMSF struggle to provide a better prediction than the reference. However, a relative operating characteristic and reliability analysis of the full 19 month period reveals that although the GMSF and XRFF possess discriminatory skill, events tend to be overforecast.
Refractive‐Light‐Transmission Technique Applied to Density‐Driven Convective Mixing in Porous Media With Implications for Geological CO2 Storage
Authors: Rasmusson M. , Fagerlund F. , Rasmusson K. , Tsang Y. , Niemi A. 
Published: October 2017

AbstractDensity‐driven convection has been identified to accelerate the rate of CO2 solubility trapping during geological CO2 storage in deep saline aquifers. In this paper, we present an experimental method using the refractive properties of fluids (their impact on light transmission), and an analogous system design, which enables the study of transport mechanisms in saturated porous media. The method is used to investigate solutally induced density‐driven convective mixing under conditions relevant to geological CO2 storage. The analogous system design allows us by choice of initial solute concentration and bead size to duplicate a wide range of conditions (
‐values), making it possible to study the convective process in general, and as a laboratory analogue for systems found in the field. We show that the method accurately determines the solute concentration in the system with high spatial and temporal resolution. The onset time of convection (
), mass flux (
), and flow dynamics are quantified and compared with experimental and numerical findings in the literature. Our data yield a scaling law for
which gives new insight into its dependence on
, indicating
to be more sensitive to large
than previously thought. Furthermore, our data show and explain why
is described equally well by a
‐dependent or a
‐independent scaling law. These findings improve the understanding of the physical process of convective mixing in saturated porous media in general and help to assess the CO2 solubility trapping rate under certain field conditions.
Evaporation From Soil Containers With Irregular Shapes
Authors: Assouline Shmuel , Narkis Kfir 
Published: October 2017

AbstractEvaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.