bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glacial and Hydrothermal Sources of Dissolved Iron (II) in Southern Ocean Waters Surrounding Heard and McDonald Islands
Authors: Holmes Thomas M. , Wuttig Kathrin , Chase Zanna , Schallenberg Christina , van der Merwe Pier , Townsend Ashley T. , Bowie Andrew R. 
Published: September 2020

AbstractThe Southern Ocean is the largest region in which iron limits the growth of phytoplankton. However, a phytoplankton bloom thousands of square kilometers in area forms each spring–summer in the Indian sector of the Southern Ocean, both above and to the east of the Kerguelen Plateau. The central region of the Kerguelen Plateau hosts the volcanically active islands, Heard and McDonald (HIMI), the former of which is largely covered by glaciers. The sources and processes governing supply of iron from HIMI to the region are relatively unknown. In the austral summer of 2016, the first voyage to focus on biogeochemical cycling in the HIMI region was undertaken (GEOTRACES process study GIpr05). Using dissolved iron (II) (DFe (II)) and hydrogen peroxide (H2O2) measurements, we are able to resolve iron sources and show that each of the adjacent islands are strong sources of reduced iron, though controlled by different supply mechanisms.At Heard Island, the greatest DFe (II) concentrations (0.57 nmol L−1) were detected north of the island. An inverse correlation of DFe (II) concentrations with salinity suggests the origin is from a sea‐terminating glacier on the island. At McDonald Islands, the greatest DFe (II) concentrations (1.01 nmol L−1) were detected east of the islands, which, based on DFe (II) profiles from five targeted stations, appear likely to originate from shallow diffuse hydrothermalism. Elevated DFe (II) around HIMI may increase Fe availability for biota and has implications for transport of Fe away from the islands to the broader northern Kerguelen Plateau where the annual plankton bloom is strongest.
Coherent Seasonal Acceleration of the Weddell Sea Boundary Current System Driven by Upstream Winds
Authors: Le Paih Nicolas , Hattermann Tore , Boebel Olaf , Kanzow Torsten , Lüpkes Christof , Rohardt Gerd , Strass Volker , Herbette Steven 
Published: September 2020

AbstractThe Weddell Sea is of global importance in the formation of dense bottom waters associated with sea ice formation and ocean‐ice sheet interaction occurring on the shelf areas. In this context, the Weddell Sea boundary current system (BCS) presents a major conduit for transporting relatively warm water to the Weddell Sea ice shelves and for exporting some modified form of Wedell Sea deep and bottom waters into the open ocean. This study investigates the downstream evolution of the structure and the seasonality of the BCS along the Weddell Sea continental slope, combining ocean data collected for the past two decades at three study locations. The interannual‐mean geostrophic flow, which follows planetary potential vorticity contours, shifts from being surface intensified to bottom intensified along stream. The shift occurs due to the densification of water masses and the decreasing surface stress that occurs westward, toward the Antarctic Peninsula. A coherent along‐slope seasonal acceleration of the barotropic flow exists, with maximum speed in austral autumn and minimum speed in austral summer. The barotropic flow significantly contributes to the seasonal variability in bottom velocity along the tip of the Antarctic Peninsula. Our analysis suggests that the winds on the eastern/northeastern side of the gyre determines the seasonal acceleration of the barotropic flow. In turn, they might control the export of Weddell Sea Bottom Water on seasonal time scales. The processes controlling the baroclinic seasonality of the flow need further investigation.
Evaluating Wildfire Smoke Transport Within a Coupled Fire‐Atmosphere Model Using a High‐Density Observation Network for an Episodic Smoke Event Along Utah's Wasatch Front
Authors: Mallia Derek V. , Kochanski Adam K. , Kelly Kerry E. , Whitaker Ross , Xing Wei , Mitchell Logan E. , Jacques Alex , Farguell Angel , Mandel Jan , Gaillardon Pierre‐Emmanuel , Becnel Tom , Krueger Steven K. 
Published: September 2020

AbstractOne of the primary challenges associated with evaluating smoke models is the availability of observations. The limited density of traditional air quality monitoring networks makes evaluating wildfire smoke transport challenging, particularly over regions where smoke plumes exhibit significant spatiotemporal variability. In this study, we analyzed smoke dispersion for the 2018 Pole Creek and Bald Mountain Fires, which were located in central Utah. Smoke simulations were generated using a coupled fire‐atmosphere model, which simultaneously renders fire growth, fire emissions, plume rise, smoke dispersion, and fire‐atmosphere interactions. Smoke simulations were evaluated using PM2.5 observations from publicly accessible fixed sites and a semicontinuously running mobile platform. Calibrated measurements of PM2.5 made by low‐cost sensors from the Air Quality and yoU (AQ&U) network were within 10% of values reported at nearby air quality sites that used Federal Equivalent Methods. Furthermore, results from this study show that low‐cost sensor networks and mobile measurements are useful for characterizing smoke plumes while also serving as an invaluable data set for evaluating smoke transport models. Finally, coupled fire‐atmosphere model simulations were able to capture the spatiotemporal variability of wildfire smoke in complex terrain for an isolated smoke event caused by local fires. Results here suggest that resolving local drainage flow could be critical for simulating smoke transport in regions of significant topographic relief.
Biomechanical Properties and Resistance to Uprooting of Laboratory‐Scale Wood Logs
Authors: Bau' Valentina , Perona Paolo 
Published: September 2020

AbstractWood dynamics affects riparian ecosystem functioning and river morphology. The spatial and temporal dynamics of wood pieces in river corridors, in particular of deposited rejuvenated wood logs, depend on their biomechanical properties and resistance to uprooting. The ability of stranded wood logs to withstand drag forces depends on how efficiently their roots have sprouted and on the interarrival time, magnitude, and duration of the moderate floods to which they are subjected. We performed static pullout tests on small‐scale wood logs (Salix species) of four different sizes, growth stages, and sediment moisture content. Statistics of root biomass growth rate and related spatial distribution along the trunk reveal important insights for upscaling dynamics. Similarly, force‐displacement curves indicate the maximum resistance and related energy for uprooting. Autocorrelation analysis of the sequence of force drops in the force‐displacement signal reveals the statistical nature of the mechanism of load redistribution among roots. These results are then used to advance a physically based mathematical model of the resistance of wood log roots to flow‐induced drag forces. Given that the magnitude, duration, and return period of hydrologic events are typically correlated, our model implies the existence of windows of opportunity for wood logs to either survive or remobilize.
Soil Degradation Risks Assessed by the SOTE Model for Salinity and Sodicity
Authors: Kramer Isaac , Mau Yair 
Published: September 2020

AbstractSoil salinity and sodicity are serious environmental hazards, with the potential to limit agricultural production and cause destructive soil degradation. These concerns are especially high in dry areas, which often rely on saline and sodic irrigation water to support agriculture. To assess long‐term soil degradation risk, we introduce the Salt of the Earth (SOTE) model, which describes the dynamics of soil water content, salinity, and sodicity, as driven by irrigation and rainfall. The SOTE model incorporates how changes in salinity and sodicity affect saturated soil hydraulic conductivity, Ks, on a soil‐specific basis. The model was successfully validated against results from a multiyear lysimeter experiment involving different irrigation water qualities and precipitation. We evaluated the impact of shorter rainy seasons on the dynamics of soil degradation in a Mediterranean climate. Critical degradation risk, indicated by reductions in Ks greater than 20%, increased from 0% to 3% when the rainy season was shortened from 130 to 80 days. Alarmingly, when irreversible degradation is allowed for, overall risk increases to 68%. Assessing the effect of irrigation water on different soils textures, we found that while greater clay fractions are usually more susceptible to dispersion, accurate risk assessment hinges on soil water dynamics. SOTE is amenable to large‐ensemble simulations of stochastic climatic conditions, for which trends in the statistics of salinization and soil degradation can be identified. As such, SOTE can be a useful land management tool, allowing planners to understand the risk of long‐term soil degradation given irrigation practices, soil qualities, and climate conditions.
On the Limitations and Implications of Modeling Heat Transport in Porous Aquifers by Assuming Local Thermal Equilibrium
Authors: Gossler Manuel A. , Bayer Peter , Rau Gabriel C. , Einsiedl Florian , Zosseder Kai 
Published: September 2020

AbstractHeat transport in natural porous media, such as aquifers or streambeds, is generally modeled assuming local thermal equilibrium (LTE) between the fluid and solid phases. Yet, the mathematical and hydrogeological conditions and implications of this simplification have not been fully established for natural porous media. To quantify the occurrence and effects of local thermal disequilibrium during heat transport, we systematically compared thermal breakthrough curves from a LTE with those calculated using a local thermal nonequilibrium (LTNE) model, explicitly allowing for different temperatures in the fluid and solid phases. For the LTNE model, we developed a new correlation for the heat transfer coefficient representative of the conditions in natural porous aquifers using six published experimental results. By conducting an extensive parameter study (>50,000 simulations), we show that LTNE effects do not occur for grain sizes smaller than 7 mm or for groundwater flow velocities that are slower than 1.6 m day−1. The limits of LTE are likely exceeded in gravel aquifers or in the vicinity of pumped bores. For such aquifers, the use of a LTE model can lead to an underestimation of the effective thermal dispersion by a factor of up to 30 or higher, while the advective thermal velocity remains unaffected for most conditions. Based on a regression analysis of the simulation results, we provide a criterion which can be used to determine if LTNE effects are expected for particular conditions.
Extreme Value Snow Water Equivalent and Snowmelt for Infrastructure Design Over the Contiguous United States
Authors: Cho Eunsang , Jacobs Jennifer M. 
Published: September 2020

AbstractSnowmelt‐driven floods result in large societal and economic impacts on local communities including infrastructure failures in the United States. However, the current U.S. government standard design precipitation maps are based on liquid precipitation data (e.g., National Oceanic and Atmospheric Administration's Precipitation‐Frequency Atlas 14; NOAA Atlas 14) with very limited guidance on snowmelt‐driven floods. In this study, we developed 25‐ and 100‐year return level design maps of snow water equivalent (SWE) and 1‐ and 7‐day snowmelt including precipitation events (e.g., rain‐on‐snow) using long‐term observation‐based gridded SWE developed by University of Arizona (UA) incorporating the national snow model product (SNOw Data Assimilation System; SNODAS) over the contiguous United States (CONUS). For the 44 U.S. states where the NOAA Atlas 14 maps are available, the design snowmelt values from this study exceed the standard design values in 23% of the total extent. The snowmelt values exceed the NOAA Atlas 14 design precipitation by up to 171 and 254 mm in the northeastern United States; 127 and 225 mm in the north central United States; and 191 and 425 mm in the western mountain United States for the 25‐ and 100‐year return levels, respectively. A comparison of 7‐day design snowmelt between with and without precipitation shows that including precipitation results in an average increase of 42 and 68 mm for 25‐ and 100‐year return levels, respectively, over snowmelt that do not include precipitation. The design snowmelt maps from this study complement the NOAA Atlas 14 design precipitation and provide additional guidance on infrastructure design for snowmelt‐driven floods in the CONUS.
Endothelin 1-induced retinal ganglion cell death is largely mediated by JUN activation
Authors: Marola Olivia J. , Syc-Mazurek Stephanie B. , Howell Gareth R. , Libby Richard T. 
Published: September 2020

AbstractGlaucoma is a neurodegenerative disease characterized by loss of retinal ganglion cells (RGCs), the output neurons of the retina. Multiple lines of evidence show the endothelin (EDN, also known as ET) system is important in glaucomatous neurodegeneration. To date, the molecular mechanisms within RGCs driving EDN-induced RGC death have not been clarified. The pro-apoptotic transcription factor JUN (the canonical target of JNK signaling) and the endoplasmic reticulum stress effector and transcription factor DNA damage inducible transcript 3 (DDIT3, also known as CHOP) have been shown to act downstream of EDN receptors. Previous studies demonstrated that JUN and DDIT3 were important regulators of RGC death after glaucoma-relevant injures. Here, we characterized EDN insult in vivo and investigated the role of JUN and DDIT3 in EDN-induced RGC death. To accomplish this, EDN1 ligand was intravitreally injected into the eyes of wildtype, Six3-cre+Junfl/fl (Jun−/−), Ddit3 null (Ddit3−/−), and Ddit3−/−Jun−/− mice. Intravitreal EDN1 was sufficient to drive RGC death in vivo. EDN1 insult caused JUN activation in RGCs, and deletion of Jun from the neural retina attenuated RGC death after EDN insult. However, deletion of Ddit3 did not confer significant protection to RGCs after EDN1 insult. These results indicate that EDN caused RGC death via a JUN-dependent mechanism. In addition, EDN signaling is known to elicit potent vasoconstriction. JUN signaling was shown to drive neuronal death after ischemic insult. Therefore, the effects of intravitreal EDN1 on retinal vessel diameter and hypoxia were explored. Intravitreal EDN1 caused transient retinal vasoconstriction and regions of RGC and Müller glia hypoxia. Thus, it remains a possibility that EDN elicits a hypoxic insult to RGCs, causing apoptosis via JNK-JUN signaling. The importance of EDN-induced vasoconstriction and hypoxia in causing RGC death after EDN insult and in models of glaucoma requires further investigation.
RNF115 deletion inhibits autophagosome maturation and growth of gastric cancer
Authors: Li Riyong , Gu Zhaohui , Zhang Xuan , Yu Jiahong , Feng Jinqiu , Lou Yaxin , Lv Ping , Chen Yingyu 
Published: September 2020

AbstractAutophagy is a highly conserved lysosome-dependent degradation system in eukaryotic cells. This process removes long-lived intracellular proteins, damaged organelles, and recycles biological material to maintain cellular homeostasis. Dysfunction of autophagy triggers a wide spectrum of human diseases, including cancer and neurodegenerative diseases. In the present study, we show that RNF115, an E3 ubiquitin ligase, regulates autophagosome–lysosome fusion and autophagic degradation under both nutrient-enriched and stress conditions. Depletion of theRNF115gene caused the accumulation of autophagosomes by impairing fusion with lysosomes, which results in an accumulation of autophagic substrates. Further investigation suggests that RNF115 interacts with STX17 and enhances its stability, which is essential for autophagosome maturation. Importantly, we provide in vitro and in vivo evidence thatRNF115inactivation inhibits the tumorigenesis and metastasis of BGC823 gastric cancer cells. We additionally show that high expression levels ofRNF115mRNA correlate with poor prognosis in gastric cancer patients. These findings indicate that RNF115 may play an evolutionarily conserved role in the autophagy pathway, and may act to maintain protein homeostasis under physiological conditions. These data demonstrate the need to further evaluate the potential therapeutic implications of RNF115 in gastric cancer.
Vascular toxicity associated with anti-angiogenic drugs
Authors: Neves Karla B. , Montezano Augusto C. , Lang Ninian N. , Touyz Rhian M. 
Published: September 2020

Abstract
Over the past two decades, the treatment of cancer has been revolutionised by the highly successful introduction of novel molecular targeted therapies and immunotherapies, including small-molecule kinase inhibitors and monoclonal antibodies that target angiogenesis by inhibiting vascular endothelial growth factor (VEGF) signaling pathways. Despite their anti-angiogenic and anti-cancer benefits, the use of VEGF inhibitors (VEGFi) and other tyrosine kinase inhibitors (TKIs) has been hampered by potent vascular toxicities especially hypertension and thromboembolism. Molecular processes underlying VEGFi-induced vascular toxicities still remain unclear but inhibition of endothelial NO synthase (eNOS), reduced nitric oxide (NO) production, oxidative stress, activation of the endothelin system, and rarefaction have been implicated. However, the pathophysiological mechanisms still remain elusive and there is an urgent need to better understand exactly how anti-angiogenic drugs cause hypertension and other cardiovascular diseases (CVDs). This is especially important because VEGFi are increasingly being used in combination with other anti-cancer dugs, such as immunotherapies (immune checkpoint inhibitors (ICIs)), other TKIs, drugs that inhibit epigenetic processes (histone deacetylase (HDAC) inhibitor) and poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors, which may themselves induce cardiovascular injury. Here, we discuss vascular toxicities associated with TKIs, especially VEGFi, and provide an up-to-date overview on molecular mechanisms underlying VEGFi-induced vascular toxicity and cardiovascular sequelae. We also review the vascular effects of VEGFi when used in combination with other modern anti-cancer drugs.
Reliability enhanced SiC MOSFET with partially widened retrograde P‐well structure
Authors: Liu Jiawei , Lu Jiang , Tian Xiaoli , Chen Hong , Bai Yun , Liu Xinyu 
Published: September 2020

In this Letter, a 1.2 kV SiC power MOSFET with a partially widened retrograde P‐well (RP) structure and N ‐implanting region is proposed to enhance the device's reliability. Compared with the conventional SiC power MOSFET, the short circuit (SC) ability of the proposed structure can be improved effectively without sacrificing other performance. Simulation results reveal that a 40% reduction of the SC saturation current can be achieved, resulting in the SC withstand time increase from 7 to 10 μs at the DC‐link voltage 800 V. Moreover, a better gate oxide reliability at 1.2 kV blocking condition also can be achieved. The peak electric field at the gate oxide interface is decreased by ∼48% owing to the shielding effect of the RP structure. In addition, the fabrication technology of the proposed structure is compatible with the standard planar SiC MOSFET manufacture process only with a few additional implanting steps. Therefore, this new MOSFET structure provides a simple and effective way to optimise the reliability of the planar SiC power MOSFET.
Frequency comb investigation of monolithic mode‐locked GaSb‐based laser at 1.7 µm by heterodyne detection
Authors: Becker S. , Weih R. , Scheuermann J. , Rößner K. , Kistner C. , Koeth J. , Höfling S. , Kamp M. 
Published: September 2020

In this work, monolithic mode‐locked GaSb‐based lasers at 1.7 µm emission wavelength with heterodyne measurement of the frequency comb are presented. Mode‐locking operation was confirmed by measuring the optical beatnote at the round‐trip frequency of 9.56 GHz and analysing the frequency comb. Mode‐locking operation occurred from 0.1 to 3.3 V reverse bias voltages at the absorber section and driving currents from 160 to 400 mA at the laser section with a minimum beatnote width of 6.6 kHz. The frequency comb spans over 13 nm with a mode spacing of 0.10 nm, measured by heterodyne‐detection with a distributed feedback laser.
Spike‐driven gated recurrent neural network processor for electrocardiogram arrhythmias detection realised in 55‐nm CMOS technology
Authors: Wu Yuancong , Liu Y.H. , Liu Shuang , Yu Q. , Chen T.P. , Liu Y. 
Published: September 2020

In this Letter, an asynchronous spike‐driven processor based on gated recurrent neural network algorithm for electrocardiogram (ECG) cardiac arrhythmias detection has been designed. Based on the processor, the proposed ECG detection model, containing a many‐to‐many gated recurrent unit layer and a fully connected layer, can achieve a high classification overall accuracy of 97.8% using the MIT‐BIH arrhythmia database. The processor was fabricated in 55‐nm 1P6M CMOS technology. It integrates about 1.4 million logic gates, including 40 KB of on‐chip memory within a die area. The test chip consumes 6.28 mW at real‐time operation frequency (200 MHz) with 1.2 V core supply voltage and at 1 kHz.
Near‐field uniformity analysis and compensation for finite‐sized beam combiner with the asymmetric layout
Authors: Hao Kaizi , Li Zhuo , Wang Xin , Zhou Lang , Wang Yiting 
Published: September 2020

In a hardware‐in‐the‐loop simulation system, the insertion of an asymmetric layout beam combiner will seriously affect the near‐field uniformity. In this study, the effects of the aperture shape, transverse distance and size of the beam combiner on the near‐field uniformity were analysed. The square beam combiner with a transverse distance of 0.51 m and a size of 1.05 m × 1.05 m was regarded as the optimal design, but it still cannot meet the test requirements. In order to obtain excellent near‐field uniformity, an asymmetric Uniform + Linear taper compensation method was proposed. The maximum values of the amplitude fluctuation (Epv) and phase ripple (φpv) decreased dramatically from 2.62 dB and 16.79° to 0.78 dB and 7.42°, respectively. Asymmetric Uniform + Linear taper was achieved through serrating the edge of the beam combiner. When the number of serrations N was 22, Epv and φpv were <0.83 dB and 7.50°, respectively, which indicated that the near‐field uniformity can be significantly improved by asymmetric Uniform + Linear taper.
Dual‐output AC–DC converter with three‐port bridgeless PFC and non‐isolated DCX
Authors: Xu Xinyu , Jia Yihang , Wu Hongfei , Zhang Yanfeng 
Published: September 2020

This study proposed a dual‐output AC–DC converter based on three‐port bridgeless power factor corrector (TPB‐PFC) and a non‐isolated resonant DC‐transformer (Ni‐DCX) for dual‐output DC voltage applications. A constant DC output voltage and a variable DC output voltage are provided simultaneously by the proposed AC–DC converter. Based on the TPB‐PFC converter, a stacked power conversion structure with reduced power conversion stage is presented. Therefore, lower power losses and higher efficiencies are achieved. Meanwhile, soft switching of all the power devices in the Ni‐DCX is achieved with open‐loop controlled and optimised operation of the Ni‐DCX, resulting in easy control and higher efficiency. In addition, switching losses of the TPB‐PFC are reduced thanks to the three‐level characteristic. Operation principles and characteristics of both TPB‐PFC and Ni‐DCX converter, and modulation and control strategies of the proposed AC–DC converter are analysed in detail. Feasibility and effectiveness of the proposed solutions are verified experimentally with a 2 kW dual‐output AC–DC prototype.