bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiative Effects of Secondary Ice Enhancement in Coastal Antarctic Clouds
Authors: Young G. , Lachlan‐Cope T. , O'Shea S. J. , Dearden C. , Listowski C. , Bower K. N. , Choularton T. W. , Gallagher M. W. 
Published: February 2019

AbstractSecondary ice production (SIP) commonly occurs in coastal Antarctic stratocumulus, affecting their ice number concentrations (Nice) and radiative properties. However, SIP is poorly understood and crudely parametrized in models. By evaluating how well SIP is captured in a cloud‐resolving model, with a high‐resolution nest within a parent domain, we test how an improved comparison with aircraft observations affects the modeled cloud radiative properties. Under the assumption that primary ice is suitably represented by the model, we must enhance SIP by up to an order of magnitude to simulate observed Nice. Over the nest, a surface warming trend accompanied the SIP increase; however, this trend was not captured by the parent domain over the same region. Our results suggest that the radiative properties of microphysical features resolved in high‐resolution nested domains may not be captured by coarser domains, with implications for large‐scale radiative balance studies over the Antarctic continent.
Oxidation of Volatile Organic Compounds as the Major Source of Formic Acid in a Mixed Forest Canopy
Authors: Alwe Hariprasad D. , Millet Dylan B. , Chen Xin , Raff Jonathan D. , Payne Zachary C. , Fledderman Kathryn 
Published: February 2019

AbstractFormic acid (HCOOH) is among the most abundant carboxylic acids in the atmosphere, but its budget is poorly understood. We present eddy flux, vertical gradient, and soil chamber measurements from a mixed forest and apply the data to better constrain HCOOH source/sink pathways. While the cumulative above‐canopy flux was downward, HCOOH exchange was bidirectional, with extended periods of net upward and downward flux. Net above‐canopy fluxes were mostly upward during warmer/drier periods. The implied gross canopy HCOOH source corresponds to 3% and 38% of observed isoprene and monoterpene carbon emissions and is 15× underestimated in a state‐of‐science atmospheric model (GEOS‐Chem). Gradient and soil chamber measurements identify the canopy layer as the controlling source of HCOOH or its precursors to the forest environment; below‐canopy sources were minor. A correlation analysis using an ensemble of marker volatile organic compounds suggests that secondary formation, not direct emission, is the major source driving ambient HCOOH.
The Role of Atmospheric Rivers for Extreme Ablation and Snowfall Events in the Southern Alps of New Zealand
Authors: Little K. , Kingston D. G. , Cullen N. J. , Gibson P. B. 
Published: February 2019

AbstractThe role of atmospheric rivers (ARs) for extreme ablation and snowfall is examined at Brewster Glacier in the Southern Alps, the site of the longest glacier mass balance record in New Zealand. By global standards, New Zealand is strongly impacted by ARs. Here it is shown for the first time (in New Zealand) that ARs strongly contribute to extreme snowfall and ablation and thus mass balance overall. Vertically integrated water vapor transport (IVT) exceeds 1,600 (800) kg·m−1·s−1 for the largest ablation (snowfall) events, marking these as very strong ARs. The proximity to the freezing threshold during extreme snowfall events indicates the sensitivity of mass balance to temperature variation. Importantly, similarly high rates of IVT during some extreme ablation and snowfall events also occur outside of conventional AR spatial structures. This finding indicates that AR detection algorithms may substantially underestimate the importance of extreme IVT for New Zealand and elsewhere.
Search Space Representation and Reduction Methods to Enhance Multiobjective Water Supply Monitoring Design
Authors: Bode Felix , Reed Patrick , Reuschen Sebastian , Nowak Wolfgang 
Published: February 2019

AbstractOptimal design of groundwater monitoring networks is challenging due to (1) conflicting objectives for assessing the performance of candidate monitoring networks, (2) uncertainty in system dynamics and hydrogeological context, and (3) the large decision space of possible monitoring‐well positions (also termed the search space). The immensity of the search space poses a significant challenge for modern multiobjective optimization tools. This study introduces two approaches that improve the efficiency and effectiveness of evolutionary multiobjective optimization tools when solving monitoring design problems. We show how a careful mathematical representation of the monitoring design search space and reductions of possible monitoring‐well positions enhance the solution and attainment of decision‐relevant multiobjective trade‐offs in monitoring quality. We demonstrate the value of our improved representation and reduction techniques on a three‐objective monitoring network design problem focused on urban source water protection (termed the U_Protect benchmarking problem). U_Protect abstracts a real‐world case study within an urban drinking‐water well catchment, including inaccessible and restricted areas for monitoring‐well installation, and random heterogeneities in the conductivity field. Our representation and reduction methods significantly enhance the effectiveness, efficiency, and reliability of the optimization. Our proposed framework shifts focus to the most impactful monitoring design decisions while also enhancing decision makers understanding of key performance trade‐offs. In combination, our proposed representation and reduction techniques have significant promise for enhancing the size and the scope of combinatorial monitoring problems that can be explored.
Global Dynamics of Stored Precipitation Water in the Topsoil Layer From Satellite and Reanalysis Data
Authors: Kim Hyunglok , Lakshmi Venkat 
Published: February 2019

AbstractThe amount of soil water in the topsoil layer (from 0 to 10 cm) has been regarded as a key factor in controlling land‐atmosphere interaction by determining the fraction of net radiation. In the present study, we investigate spatial trends of the stored precipitation fraction in the topsoil layer for varying vegetation and aridity indices by utilizing four satellites and two reanalysis data sets on a global scale. Using the Budyko framework, we relate climate regimes to the stored precipitation fraction on a global scale. A positive relation between the stored precipitation fraction with aridity index and a negative relation between the stored precipitation fraction and free parameter, vegetation optical depth, and isohydric slope are discovered. Even though the stored precipitation fraction values were calculated from different soil moisture and precipitation sources, they share an similar spatial trend: the drier and less vegetated the soil is, the more precipitation is retained in the top layer of the soil. Specifically, the topsoil retains 37% ± 11% of precipitated water three days after a rainfall event where the aridity index was greater than 5. Over wet and forest areas, due to large runoff fluxes and plants intercepting water before the precipitated water reached the ground, the topsoil retains 21% ± 2% of precipitated water three days after a rainfall event. Furthermore, by using the modeled data sets in the calculation of the stored precipitation fraction metric, we are able to conduct a sensitivity analysis of FP(f) metrics with respect to different sampling frequency values.
Pore‐Scale Dissolution by CO2 Saturated Brine in a Multimineral Carbonate at Reservoir Conditions: Impact of Physical and Chemical Heterogeneity
Authors: Al‐Khulaifi Yousef , Lin Qingyang , Blunt Martin J. , Bijeljic Branko 
Published: February 2019

AbstractWe study the impact of physical and chemical heterogeneity on reaction rates in multimineral porous media. We selected two pairs of carbonate samples of different physical heterogeneity in accordance with their initial computed velocity distributions and then injected CO2 saturated brine at reservoir conditions at two flow rates. We periodically imaged the samples using X‐ray microtomography. The mineralogical composition was similar (a ratio of dolomite to calcite of 8:1), but the intrinsic reaction rates and mineral spatial distribution were profoundly different. Visualizations of velocity fields and reacted mineral distributions revealed that a dominant flow channel formed in all cases. The more physically homogeneous samples had a narrower velocity distribution and more preexisting fast channels, which promoted dominant channel formation in their proximity. In contrast, the heterogeneous samples exhibit a broader distribution of velocities and fewer fast channels, which accentuated nonuniform calcite distribution and favored calcite dissolution away from the initially fast pathways. We quantify the impact of physical and chemical heterogeneity by computing the proximity of reacted minerals to the fast flow pathways. The average reaction rates were an order of magnitude lower than the intrinsic ones due to mass transfer limitations. The effective reaction rate of calcite decreased by an order of magnitude, in both fast channels and slow regions. After channel formation calcite was shielded by dolomite whose effective rate in slow regions could even increase. Overall, the preferential channeling effect, as opposed to uniform dissolution, was promoted by a higher degree of physical and/or chemical heterogeneity.
How Important Are Model Structural and Contextual Uncertainties when Estimating the Optimized Performance of Water Resource Systems?
Authors: Dobson Barnaby , Wagener Thorsten , Pianosi Francesca 
Published: February 2019

AbstractUncertainty in simulating water resource systems (WRSs) makes it difficult to assess how effective different water management decisions will be. Uncertainty in simulation models can undermine the credibility of simulation and optimization studies and the uptake of their results. We identify different sources of uncertainty in WRS models and find that structural uncertainty (i.e., around definition of interrelationships within the system) and contextual uncertainty (i.e., around definition of the system boundaries) are rarely considered when simulating and optimizing WRSs. We propose a methodology to quantify the effects of structural and contextual uncertainties on the estimated performance of optimized water management decisions and demonstrate that they have a significant impact on a real‐world case study of a pumped‐storage system in the UK. To the best of the authors' knowledge, this is the first study to consider the impact of these types of uncertainty on optimized operating policies and their simulated performances. Our main finding is that of all the considered uncertainties, the assumptions made about context—specifically around the level of cooperation between neighboring water companies—had the greatest impact on performance estimates. This is important because few WRSs exist in isolation, yet discussion of the effects that a given definition of the system boundaries have on the simulation/optimization results is uncommon. We also highlight the significance of adequately considering aleatory uncertainty when evaluating performance estimates—something that few studies do—and present a simple technique to justify the sample size used for the evaluation of optimization results.
System Modeling, Optimization, and Analysis of Recycled Water and Dynamic Storm Water Deliveries to Spreading Basins for Urban Groundwater Recharge
Authors: Bradshaw Jonathan L. , Osorio Mauricio , Schmitt Theo G. , Luthy Richard G. 
Published: February 2019

AbstractTo bolster freshwater supplies, water managers are increasingly interested in recharging groundwater using storm water and recycled water. However, such multisupply groundwater recharge projects are hindered by the lack of planning tools to evaluate system design costs and trade‐offs. This study presents modeling advancements that provide enhanced insights into multisupply spreading basin systems (i.e., spreading basins that accommodate both advanced treated recycled water and dynamically available storm water), a form of managed aquifer recharge. The model identifies system designs that optimize infrastructure life cycle cost and water volumes infiltrated for groundwater recharge. To illustrate the model's application under realistic conditions, we present a case study of Los Angeles, California. In this case study, we find that competition between storm water and recycled water for spreading basin use is relatively minor. Moreover, compared to systems based on existing conservative assumptions, our methods identify optimal dynamic system designs that are 5%–20% more cost‐effective, primarily resulting from higher water recycling facility utilization. Overall, this approach, which considers the dynamic nature of storm water availability and variable recycled water production, can inform water planners of the cost, water volume, and energy trade‐offs associated with different multisupply spreading basin system designs, including varying levels of centralization.
A negative feedback loop between XBP1 and Fbw7 regulates cancer development
Authors: Chae Unbin , Lee Heejin , Kim Bokyung , Jung Haiyoung , Kim Byeong Mo , Lee Ann- Hwee , Lee Dong-Seok , Min Sang-Hyun 
Published: February 2019

AbstractIn cancer, activation of X-box binding protein (XBP1) has a critical role in tumorigenesis and cancer progression. Transcriptional regulatory mechanism of XBP1 in cancer development has been well known, however, regulation of ubiquitination and degradation of XBP1 has not been elucidated yet. Here we show that Fbw7, a substrate recognition component of the SKP1-Cullin-F-box-type E3 ligase, interacts with XBP1 in a phosphorylation-dependent manner, and facilitates XBP1 ubiquitination and protein degradation. Moreover, Fbw7 inhibits oncogenic pathways including NF-κB, AP1, and Myc induced by XBP1. Interestingly, XBP1 negatively regulates transcription of Fbw7 via a feedback mechanism through NF-κB/E2F-1 axis signaling pathway, suggesting that overexpression of XBP1s may contribute to low level of Fbw7 expression in human cancers. Therefore, a negative feedback loop between Fbw7 and XBP1 contributes to the regulation of tumor development and can be an attractive target for novel therapy in cancers.
An FBXW7-ZEB2 axis links EMT and tumour microenvironment to promote colorectal cancer stem cells and chemoresistance
Authors: Li Ningning , Babaei-Jadidi Roya , Lorenzi Federica , Spencer-Dene Bradley , Clarke Philip , Domingo Enric , Tulchinsky Eugene , Vries Robert G. J. , Kerr David , Pan Yihang , He Yulong , Bates David O. , Tomlinson Ian , Clevers Hans , Nateri Abdolrahman S. 
Published: February 2019

AbstractColorectal cancer (CRC) patients develop recurrence after chemotherapy owing to the survival of stem cell-like cells referred to as cancer stem-like cells (CSCs). The origin of CSCs is linked to the epithelial–mesenchymal transition (EMT) process. Currently, it remains poorly understood how EMT programmes enable CSCs residing in the tumour microenvironment to escape the effects of chemotherapy. This study identifies a key molecular pathway that is responsible for the formation of drug-resistant CSC populations. Using a modified yeast-2-hybrid system and 2D gel-based proteomics methods, we show that the E3-ubiquitin ligase FBXW7 directly binds and degrades the EMT-inducing transcription factor ZEB2 in a phosphorylation-dependent manner. Loss of FBXW7 induces an EMT that can be effectively reversed by knockdown of ZEB2. The FBXW7-ZEB2 axis regulates such important cancer cell features, as stemness/dedifferentiation, chemoresistance and cell migration in vitro, ex vivo and in animal models of metastasis. High expression of ZEB2 in cancer tissues defines the reduced ZEB2 expression in the cancer-associated stroma in patients and in murine intestinal organoids, demonstrating a tumour-stromal crosstalk that modulates a niche and EMT activation. Our study thus uncovers a new molecular mechanism, by which the CRC cells display differences in resistance to chemotherapy and metastatic potential.
Stereoselective synthesis of sulfur-containing β-enaminonitrile derivatives through electrochemical Csp3–H bond oxidative functionalization of acetonitrile
Authors: He Tian-Jun , Ye Zongren , Ke Zhuofeng , Huang Jing-Mei 
Published: February 2019

AbstractIncorporation of nitrile groups into fine chemicals is of particular interest through C(sp3)–H bonds activation of alkyl nitriles in the synthetic chemistry due to the highly efficient atom economy. However, the direct α-functionalization of alkyl nitriles is usually limited to its enolate chemistry. Here we report an electro-oxidative C(sp3)–H bond functionalization of acetonitrile with aromatic/aliphatic mercaptans for the synthesis of sulfur-containing β-enaminonitrile derivatives. These tetrasubstituted olefin products are stereoselectively synthesized and the stereoselectivity is enhanced in the presence of a phosphine oxide catalyst. With iodide as a redox catalyst, activation of C(sp3)–H bond to produce cyanomethyl radicals proceeds smoothly at a decreased anodic potential, and thus highly chemoselective formation of C–S bonds and enamines is achieved. Importantly, the process is carried out at ambient temperature and can be easily scaled up.
Allosteric enhancement of ORP1-mediated cholesterol transport by PI(4,5)P2/PI(3,4)P2
Authors: Dong Jiangqing , Du Ximing , Wang Huan , Wang Jue , Lu Chang , Chen Xiang , Zhu Zhiwen , Luo Zhipu , Yu Li , Brown Andrew J. , Yang Hongyuan , Wu Jia-Wei 
Published: February 2019

AbstractPhosphatidylinositol phosphates (PIPs) and cholesterol are known to regulate the function of late endosomes and lysosomes (LELs), and ORP1L specifically localizes to LELs. Here, we show in vitro that ORP1 is a PI(4,5)P2- or PI(3,4)P2-dependent cholesterol transporter, but cannot transport any PIPs. In cells, both ORP1L and PI(3,4)P2are required for the efficient removal of cholesterol from LELs. Structures of the lipid-binding domain of ORP1 (ORP1-ORD) in complex with cholesterol or PI(4,5)P2display open conformations essential for ORP function. PI(4,5)P2/PI(3,4)P2can facilitate ORP1-mediated cholesterol transport by promoting membrane targeting and cholesterol extraction. Thus, our work unveils a distinct mechanism by which PIPs may allosterically enhance OSBP/ORPs-mediated transport of major lipid species such as cholesterol.
Path integration maintains spatial periodicity of grid cell firing in a 1D circular track
Authors: Jacob Pierre-Yves , Capitano Fabrizio , Poucet Bruno , Save Etienne , Sargolini Francesca 
Published: February 2019

AbstractEntorhinal grid cells are thought to provide a 2D spatial metric of the environment. In this study we demonstrate that in a familiar 1D circular track (i.e., a continuous space) grid cells display a novel 1D equidistant firing pattern based on integrated distance rather than travelled distance or time. In addition, field spacing is increased compared to a 2D open field, probably due to a reduced access to the visual cue in the track. This metrical modification is accompanied by a change in LFP theta oscillations, but no change in intrinsic grid cell rhythmicity, or firing activity of entorhinal speed and head-direction cells. These results suggest that in a 1D circular space grid cell spatial selectivity is shaped by path integration processes, while grid scale relies on external information.
Decoding the 5′ nucleotide bias of PIWI-interacting RNAs
Authors: Stein Chad B. , Genzor Pavol , Mitra Sanga , Elchert Alexandra R. , Ipsaro Jonathan J. , Benner Leif , Sobti Sushil , Su Yijun , Hammell Molly , Joshua-Tor Leemor , Haase Astrid D. 
Published: February 2019

AbstractPIWI-interacting RNAs (piRNAs) are at the center of a small RNA-based immune system that defends genomes against the deleterious action of mobile genetic elements (transposons). PiRNAs are highly variable in sequence with extensive targeting potential. Their diversity is restricted by their preference to start with a Uridine (U) at the 5′ most position (1U-bias), a bias that remains poorly understood. Here we uncover that the 1U-bias of Piwi-piRNAs is established by consecutive discrimination against all nucleotides but U, first during piRNA biogenesis and then upon interaction with Piwi’s specificity loop. Sequence preferences during piRNA processing also restrict U across the piRNA body with the potential to directly impact target recognition. Overall, the uncovered signatures could modulate specificity and efficacy of piRNA-mediated transposon restriction, and provide a substrate for purifying selection in the ongoing arms race between genomes and their mobile parasites.
High performance n-type Ag2Se film on nylon membrane for flexible thermoelectric power generator
Authors: Ding Yufei , Qiu Yang , Cai Kefeng , Yao Qin , Chen Song , Chen Lidong , He Jiaqing 
Published: February 2019

AbstractResearches on flexible thermoelectric materials usually focus on conducting polymers and conducting polymer-based composites; however, it is a great challenge to obtain high thermoelectric properties comparable to inorganic counterparts. Here, we report an n-type Ag2Se film on flexible nylon membrane with an ultrahigh power factor ~987.4 ± 104.1 μWm−1K−2 at 300 K and an excellent flexibility (93% of the original electrical conductivity retention after 1000 bending cycles around a 8-mm diameter rod). The flexibility is attributed to a synergetic effect of the nylon membrane and the Ag2Se film intertwined with numerous high-aspect-ratio Ag2Se grains. A thermoelectric prototype composed of 4-leg of the Ag2Se film generates a voltage and a maximum power of 18 mV and 460 nW, respectively, at a temperature difference of 30 K. This work opens opportunities of searching for high performance thermoelectric film for flexible thermoelectric devices.
Insight of Captagon Abuse by Chemogenomics Knowledgebase-guided Systems Pharmacology Target Mapping Analyses
Authors: Wu Nan , Feng Zhiwei , He Xibing , Kwon William , Wang Junmei , Xie Xiang-Qun 
Published: February 2019

AbstractCaptagon, known by its genetic name Fenethylline, is an addictive drug that complicates the War on Drugs. Captagon has a strong CNS stimulating effect than its primary metabolite, Amphetamine. However, multi-targets issues associated with the drug and metabolites as well as its underlying mechanisms have not been fully defined. In the present work, we applied our established drug-abuse chemogenomics-knowledgebase systems pharmacology approach to conduct targets/off-targets mapping (SP-Targets) investigation of Captagon and its metabolites for hallucination addiction, and also analyzed the cell signaling pathways for both Amphetamine and Theophylline with data mining of available literature. Of note, Amphetamine, an agonist for trace amine-associated receptor 1 (TAAR1) with enhancing dopamine signaling (increase of irritability, aggression, etc.), is the main cause of Captagon addiction; Theophylline, an antagonist that blocks adenosine receptors (e.g. A2aR) in the brain responsible for restlessness and painlessness, may attenuate the behavioral sensitization caused by Amphetamine. We uncovered that Theophylline’s metabolism and elimination could be retarded due to competition and/or blockage of the CYP2D6 enzyme by Amphetamine; We also found that the synergies between these two metabolites cause Captagon’s psychoactive effects to act faster and far more potently than those of Amphetamine alone. We carried out further molecular docking modeling and molecular dynamics simulation to explore the molecular interactions between Amphetamine and Theophylline and their important GPCRs targets, including TAAR1 and adenosine receptors. All of the systems pharmacology analyses and results will shed light insight into a better understanding of Captagon addiction and future drug abuse prevention.