bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transport Variability of the Irminger Sea Deep Western Boundary Current From a Mooring Array
Authors: Hopkins J. E. , Holliday N. P. , Rayner D. , Houpert L. , Le Bras I. , Straneo F. , Wilson C. , Bacon S. 
Published: April 2019

AbstractThe Deep Western Boundary Current in the subpolar North Atlantic is the lower limb of the Atlantic Meridional Overturning Circulation and a key component of the global climate system. Here, a mooring array deployed at 60°N in the Irminger Sea, between 2014 and 2016, provides the longest continuous record of total Deep Western Boundary Current volume transport at this latitude. The 1.8‐year averaged transport of water denser than σθ = 27.8 kg/m3 was −10.8 ± 4.9 Sv (mean ± 1 std; 1 Sv = 106 m3/s). Of this total, we find −4.1 ± 1.4 Sv within the densest layer (σθ > 27.88 kg/m3) that originated from the Denmark Strait Overflow. The lighter North East Atlantic Deep Water layer (σθ = 27.8–27.88 kg/m3) carries −6.5 ± 7.7 Sv. The variability in transport ranges between 2 and 65 days. There is a distinct shift from high to low frequency with distance from the East Greenland slope. High‐frequency fluctuations (2–8 days) close to the continental slope are likely associated with topographic Rossby waves and/or cyclonic eddies. Here, perturbations in layer thickness make a significant (20–60%) contribution to transport variability. In deeper water, toward the center of the Irminger Basin, transport variance at 55 days dominates. Our results suggest that there has been a 1.8 Sv increase in total transport since 2005–2006, but this difference can be accounted for by a range of methodological and data limitation biases.
A New 200‐Year Spatial Reconstruction of West Antarctic Surface Mass Balance
Authors: Wang Yetang , Huai Baojuan , Thomas Elizabeth R. , van den Broeke Michiel R. , van Wessem J. Melchior , Schlosser Elisabeth 
Published: April 2019

AbstractHigh‐spatial resolution surface mass balance (SMB) over the West Antarctic Ice Sheet (WAIS) spanning 1800–2010 is reconstructed by means of ice core records combined with the outputs of the European Centre for Medium‐Range Weather Forecasts “Interim” reanalysis (ERA‐Interim) and the latest polar version of the Regional Atmospheric Climate Model (RACMO2.3p2). The reconstruction reveals a significant negative trend (−1.9 ± 2.2 Gt/year·per decade) in the SMB over the entire WAIS during the nineteenth century, but a statistically significant positive trend of 5.4 ± 2.9 Gt/year·per decade between 1900 and 2010, in contrast to insignificant WAIS SMB changes during the twentieth century reported earlier. At regional scales, the Antarctic Peninsula and western WAIS show opposite SMB trends, with different signs in the nineteenth and twentieth centuries. The annual resolution reconstruction allows us to examine the relationships between SMB and large‐scale atmospheric oscillations. Although SMB over the Antarctic Peninsula and western WAIS correlates significantly with the Southern Annular Mode due to the influence of the Amundsen Sea Low, and El Niño/Southern Oscillation during 1800–2010, the significant correlations are temporally unstable, associated with the phase of Southern Annular Mode, El Niño/Southern Oscillation and the Pacific decadal oscillation. In addition, the two climate modes seem to contribute little to variability in SMB over the whole WAIS on decadal‐centennial time scales. This new reconstruction also serves to identify unreliable precipitation trends in ERA‐Interim and thus has potential for assessing the skill of other reanalyses or climate models to capture precipitation trends and variability.
Snow to Precipitation Ratio Controls Catchment Storage and Summer Flows in Boreal Headwater Catchments
Authors: Meriö Leo‐Juhani , Ala‐aho Pertti , Linjama Jarmo , Hjort Jan , Kløve Bjørn , Marttila Hannu 
Published: April 2019

AbstractCatchment storage sustains ecologically important low flows in headwater systems. Understanding the factors controlling storage is essential in analysis of catchment vulnerability to global change. We calculated catchment storage and storage sensitivity of streamflow for 61 boreal headwater catchments in Finland. We also explored the connection between computed storage indices and low flow conditions. The relationships between selected climate, snow, and catchment characteristics and calculated storage properties and low flows were investigated, in order to assess the importance of different factors that render catchments vulnerable to climate and environmental change. We found that the most sensitive areas to climate change were located in the southern boreal coastal zone, with fine‐grained soils and agricultural areas. In contrast, catchments in the middle and northern boreal zone, with till and peatland soils and higher snow water equivalent values, were less sensitive under current conditions. In addition, we found a threshold at a snow to precipitation ratio of 0.35. Above that threshold, summer low flows were generally sensitive to changes in snow conditions, whereas below that threshold catchment characteristics gained importance and the sensitivity was more directly related to changes in temperature and timing of rainfall. These findings suggest that a warming climate will have pronounced impacts on hydrology and catchment sensitivity related to snow quantity and snow cover duration in certain snow to precipitation ratio zones. Moreover, land use activities had an impact on storage properties in agricultural and drained peatland areas, resulting in a negative effect on low flows.
Seasonality of Rainfall in Colombia
Authors: Urrea Viviana , Ochoa Andrés , Mesa Oscar 
Published: April 2019

AbstractThe knowledge of the annual cycle of rainfall is of primary concern for many socioeconomic activities such as agricultural planning, electricity generation, and flood and other disaster management. The annual cycle of rainfall in Colombia has been studied so far using monthly or quarterly information, identifying zones with the unimodal regime (one wet season and one dry season) over the Caribbean, the Amazon, and the Pacific regions and zones with the bimodal regime (two wet and two dry seasons) in the Andes. This paper explores the annual rainfall cycle in Colombia on a daily basis using historical records of 1,706 rain gauges and the Climate Hazards Group Infrared Precipitation with Station data precipitation data set. We found four types of annual precipitation regimes: unimodal, bimodal, mixed, and aseasonal. The unimodal regime predominates in the low‐altitude zones of the east and the north, the bimodal and mixed regimes over the Andes mountain range, and the aseasonal in the Pacific region. These results improve the statistical diagnosis of the spatial variability of the rainfall seasonality in Colombia. This phenomenon, however, is still far from being fully understood in its hydroclimatic context. The annual migration of the Intertropical Convergence Zone is not enough to explain the diversity of rainfall regimes in Colombia. Local factors such as topography and land cover could play an important role in the occurrence and duration of rainfall seasons.
Mapping the Lunar Wake Potential Structure With ARTEMIS Data
Authors: Xu Shaosui , Poppe Andrew R. , Halekas Jasper S. , Mitchell David L. , McFadden James P. , Harada Yuki 
Published: April 2019

AbstractThe refilling of the lunar wake is relatively well explained by the theory of 1‐D plasma expansion into a vacuum; however, the field‐aligned wake potential is not a directly measured quantity, and thus, a statistical analysis of wake potentials at high altitudes has not been previously performed. In this study, we obtain the wake potential by comparing the field‐aligned electron distributions inside and outside of the lunar wake measured by the two probes of the Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) mission. The derived potentials from ARTEMIS data vary with solar wind electron temperature and bulk flow velocity as the theory predicts. We also expand the 1‐D plasma theory to 2‐D in the plane of the interplanetary magnetic field and the solar wind velocity to examine how a tilted interplanetary magnetic field affects the wake potential structure. As the expansion time for the two sides of the wake differs, a wake potential asymmetry is developed in our model. This asymmetry is confirmed by the data‐derived wake potentials. Moreover, ambipolar electric fields are obtained from both the modeled and data‐derived wake potentials and show good agreement. Lastly, we examine the effects of the solar wind strahl‐electron population on the wake potential structure, which appears to cause a net potential difference across the lunar shadow. This may imply that the disturbance of the wake plasma expansion extends farther outside the wake than previous plasma‐expansion theories have predicted.
Immunostimulatory nanomedicines synergize with checkpoint blockade immunotherapy to eradicate colorectal tumors
Authors: Duan Xiaopin , Chan Christina , Han Wenbo , Guo Nining , Weichselbaum Ralph R. , Lin Wenbin 
Published: April 2019

AbstractNanoparticles can potentially stimulate tumour microenvironments to elicit antitumour immunity. Herein, we demonstrate effective immunotherapy of colorectal cancer via systemic delivery of an immunostimulatory chemotherapeutic combination in nanoscale coordination polymer (NCP) core-shell particles. Oxaliplatin and dihydroartemesinin have contrasting physicochemical properties but strong synergy in reactive oxygen species (ROS) generation and anticancer activity. The combined ROS generation is harnessed for immune activation to synergize with an anti-PD-L1 antibody for the treatment of murine colorectal cancer tumours. The favourable biodistribution and tumour uptake of NCPs and the absence of peripheral neuropathy allow for repeated dosing to afford 100% tumour eradication. The involvement of innate and adaptive immune systems elicit strong and long lasting antitumour immunity which prevents tumour formation when cured mice are challenged with cancer cells. The intrinsically biodegradable, well tolerated, and systemically available immunostimulatory NCP promises to enter clinical testing as an immunotherapy against colorectal cancer.
Asymmetric division events promote variability in cell cycle duration in animal cells and Escherichia coli
Authors: Berge Ulrich , Bochenek Daria , Schnabel Ralf , Wehling Arne , Schroeder Timm , Stadler Tanja , Kroschewski Ruth 
Published: April 2019

AbstractAsymmetric cell division is a major mechanism generating cell diversity. As cell cycle duration varies among cells in mammalian tissue culture cells, we asked whether their division asymmetry contributes to this variability. We identify among sibling cells an outlier using hierarchical clustering on cell cycle durations of granddaughter cells obtained by lineage tracking of single histone2B-labelled MDCKs. Remarkably, divisions involving outlier cells are not uniformly distributed in lineages, as shown by permutation tests, but appear to emerge from asymmetric divisions taking place at non-stochastic levels: a parent cell influences with 95% confidence and 0.5% error the unequal partitioning of the cell cycle duration in its two progenies. Upon ninein downregulation, this variability propagation is lost, and outlier frequency and variability in cell cycle durations in lineages is reduced. As external influences are not detectable, we propose that a cell-autonomous process, possibly involved in cell specialisation, determines cell cycle duration variability.
Structural insight into YcbB-mediated beta-lactam resistance in Escherichia coli
Authors: Caveney Nathanael A. , Caballero Guillermo , Voedts Henri , Niciforovic Ana , Worrall Liam J. , Vuckovic Marija , Fonvielle Matthieu , Hugonnet Jean-Emmanuel , Arthur Michel , Strynadka Natalie C. J. 
Published: April 2019

AbstractThe bacterial cell wall plays a crucial role in viability and is an important drug target. In Escherichia coli, the peptidoglycan crosslinking reaction to form the cell wall is primarily carried out by penicillin-binding proteins that catalyse D,D-transpeptidase activity. However, an alternate crosslinking mechanism involving the L,D-transpeptidase YcbB can lead to bypass of D,D-transpeptidation and beta-lactam resistance. Here, we show that the crystallographic structure of YcbB consists of a conserved L,D-transpeptidase catalytic domain decorated with a subdomain on the dynamic substrate capping loop, peptidoglycan-binding and large scaffolding domains. Meropenem acylation of YcbB gives insight into the mode of inhibition by carbapenems, the singular antibiotic class with significant activity against L,D-transpeptidases. We also report the structure of PBP5-meropenem to compare interactions mediating inhibition. Additionally, we probe the interaction network of this pathway and assay beta-lactam resistance in vivo. Our results provide structural insights into the mechanism of action and the inhibition of L,D-transpeptidation, and into YcbB-mediated antibiotic resistance.
Corrupted coordination of epigenetic modifications leads to diverging chromatin states and transcriptional heterogeneity in CLL
Authors: Pastore Alessandro , Gaiti Federico , Lu Sydney X. , Brand Ryan M. , Kulm Scott , Chaligne Ronan , Gu Hongcang , Huang Kevin Y. , Stamenova Elena K. , Béguelin Wendy , Jiang Yanwen , Schulman Rafael C. , Kim Kyu-Tae , Alonso Alicia , Allan John N. , Furman Richard R. , Gnirke Andreas , Wu Catherine J. , Melnick Ari M. , Meissner Alexander , Bernstein Bradley E. , Abdel-Wahab Omar , Landau Dan A. 
Published: April 2019

AbstractCancer evolution is fueled by epigenetic as well as genetic diversity. In chronic lymphocytic leukemia (CLL), intra-tumoral DNA methylation (DNAme) heterogeneity empowers evolution. Here, to comprehensively study the epigenetic dimension of cancer evolution, we integrate DNAme analysis with histone modification mapping and single cell analyses of RNA expression and DNAme in 22 primary CLL and 13 healthy donor B lymphocyte samples. Our data reveal corrupted coherence across different layers of the CLL epigenome. This manifests in decreased mutual information across epigenetic modifications and gene expression attributed to cell-to-cell heterogeneity. Disrupted epigenetic-transcriptional coordination in CLL is also reflected in the dysregulation of the transcriptional output as a function of the combinatorial chromatin states, including incomplete Polycomb-mediated gene silencing. Notably, we observe unexpected co-mapping of typically mutually exclusive activating and repressing histone modifications, suggestive of intra-tumoral epigenetic diversity. Thus, CLL epigenetic diversification leads to decreased coordination across layers of epigenetic information, likely reflecting an admixture of cells with diverging cellular identities.
Artificial cell membrane binding thrombin constructs drive in situ fibrin hydrogel formation
Authors: Deller Robert C. , Richardson Thomas , Richardson Rebecca , Bevan Laura , Zampetakis Ioannis , Scarpa Fabrizio , Perriman Adam W. 
Published: April 2019

AbstractCell membrane re-engineering is emerging as a powerful tool for the development of next generation cell therapies, as it allows the user to augment therapeutic cells to provide additional functionalities, such as homing, adhesion or hypoxia resistance. To date, however, there are few examples where the plasma membrane is re-engineered to display active enzymes that promote extracellular matrix protein assembly. Here, we report on a self-contained matrix-forming system where the membrane of human mesenchymal stem cells is modified to display a novel thrombin construct, giving rise to spontaneous fibrin hydrogel nucleation and growth at near human plasma concentrations of fibrinogen. The cell membrane modification process is realised through the synthesis of a membrane-binding supercationic thrombin-polymer surfactant complex. Significantly, the resulting robust cellular fibrin hydrogel constructs can be differentiated down osteogenic and adipogenic lineages, giving rise to self-supporting monoliths that exhibit Young’s moduli that reflect their respective extracellular matrix compositions.
Enhanced future changes in wet and dry extremes over Africa at convection-permitting scale
Authors: Kendon Elizabeth J. , Stratton Rachel A. , Tucker Simon , Marsham John H. , Berthou Ségolène , Rowell David P. , Senior Catherine A. 
Published: April 2019

AbstractAfrican society is particularly vulnerable to climate change. The representation of convection in climate models has so far restricted our ability to accurately simulate African weather extremes, limiting climate change predictions. Here we show results from climate change experiments with a convection-permitting (4.5 km grid-spacing) model, for the first time over an Africa-wide domain (CP4A). The model realistically captures hourly rainfall characteristics, unlike coarser resolution models. CP4A shows greater future increases in extreme 3-hourly precipitation compared to a convection-parameterised 25 km model (R25). CP4A also shows future increases in dry spell length during the wet season over western and central Africa, weaker or not apparent in R25. These differences relate to the more realistic representation of convection in CP4A, and its response to increasing atmospheric moisture and stability. We conclude that, with the more accurate representation of convection, projected changes in both wet and dry extremes over Africa may be more severe.
High-order elastic multipoles as colloidal atoms
Authors: Senyuk Bohdan , Aplinc Jure , Ravnik Miha , Smalyukh Ivan I. 
Published: April 2019

AbstractAchieving and exceeding diversity of colloidal analogs of chemical elements and molecules as building blocks of matter has been the central goal and challenge of colloidal science ever since Einstein introduced the colloidal atom paradigm. Recent advances in colloids assembly have been achieved by exploiting the machinery of DNA hybridization but robust physical means of defining colloidal elements remain limited. Here we introduce physical design principles allowing us to define high-order elastic multipoles emerging when colloids with controlled shapes and surface alignment are introduced into a nematic host fluid. Combination of experiments and numerical modeling of equilibrium field configurations using a spherical harmonic expansion allow us to probe elastic multipole moments, bringing analogies with electromagnetism and a structure of atomic orbitals. We show that, at least in view of the symmetry of the “director wiggle wave functions,” diversity of elastic colloidal atoms can far exceed that of known chemical elements.
A gas-plastic elastomer that quickly self-heals damage with the aid of CO2 gas
Authors: Miwa Yohei , Taira Kenjiro , Kurachi Junosuke , Udagawa Taro , Kutsumizu Shoichi 
Published: April 2019

AbstractSelf-healing materials are highly desirable because they allow products to maintain their performance. Typical stimuli used for self-healing are heat and light, despite being unsuitable for materials used in certain products as heat can damage other components, and light cannot reach materials located within a product or device. To address these issues, here we show a gas-plastic elastomer with an ionically crosslinked silicone network that quickly self-heals damage in the presence of CO2 gas at normal pressures and room temperature. While a strong elastomer generally exhibits slow self-healing properties, CO2 effectively softened ionic crosslinks in the proposed elastomer, and network rearrangement was promoted. Consequently, self-healing was dramatically accelerated by ~10-fold. Moreover, self-healing was achieved even at −20 °C in the presence of CO2 and the original mechanical strength was quickly re-established during the exchange of CO2 with air.
Dramatic differences in carbon dioxide adsorption and initial steps of reduction between silver and copper
Authors: Ye Yifan , Yang Hao , Qian Jin , Su Hongyang , Lee Kyung-Jae , Cheng Tao , Xiao Hai , Yano Junko , Goddard William A. , Crumlin Ethan J. 
Published: April 2019

AbstractConverting carbon dioxide (CO2) into liquid fuels and synthesis gas is a world-wide priority. But there is no experimental information on the initial atomic level events for CO2 electroreduction on the metal catalysts to provide the basis for developing improved catalysts. Here we combine ambient pressure X-ray photoelectron spectroscopy with quantum mechanics to examine the processes as Ag is exposed to CO2 both alone and in the presence of H2O at 298 K. We find that CO2 reacts with surface O on Ag to form a chemisorbed species (O = CO2δ−). Adding H2O and CO2 then leads to up to four water attaching on O = CO2δ− and two water attaching on chemisorbed (b-)CO2. On Ag we find a much more favorable mechanism involving the O = CO2δ− compared to that involving b-CO2 on Cu. Each metal surface modifies the gas-catalyst interactions, providing a basis for tuning CO2 adsorption behavior to facilitate selective product formations.
A survival selection strategy for engineering synthetic binding proteins that specifically recognize post-translationally phosphorylated proteins
Authors: Meksiriporn Bunyarit , Ludwicki Morgan B. , Stephens Erin A. , Jiang Allen , Lee Hyeon-Cheol , Waraho-Zhmayev Dujduan , Kummer Lutz , Brandl Fabian , Plückthun Andreas , DeLisa Matthew P. 
Published: April 2019

AbstractThere is an urgent need for affinity reagents that target phospho-modified sites on individual proteins; however, generating such reagents remains a significant challenge. Here, we describe a genetic selection strategy for routine laboratory isolation of phospho-specific designed ankyrin repeat proteins (DARPins) by linking in vivo affinity capture of a phosphorylated target protein with antibiotic resistance of Escherichia coli cells. The assay is validated using an existing panel of DARPins that selectively bind the nonphosphorylated (inactive) form of extracellular signal-regulated kinase 2 (ERK2) or its doubly phosphorylated (active) form (pERK2). We then use the selection to affinity-mature a phospho-specific DARPin without compromising its selectivity for pERK2 over ERK2 and to reprogram the substrate specificity of the same DARPin towards non-cognate ERK2. Collectively, these results establish our genetic selection as a useful and potentially generalizable protein engineering tool for studying phospho-specific binding proteins and customizing their affinity and selectivity.
Acceleration of dolomitization by zinc in saline waters
Authors: Vandeginste Veerle , Snell Oliver , Hall Matthew R. , Steer Elisabeth , Vandeginste Arne 
Published: April 2019

AbstractDolomite (CaMg(CO3)2) plays a key role in the global carbon cycle. Yet, the chemical mechanisms that catalyze its formation remain an enigma. Here, using batch reactor experiments, we demonstrate an unexpected acceleration of dolomite formation by zinc in saline fluids, reflecting a not uncommon spatial association of dolomite with Mississippi Valley-type ores. The acceleration correlates with dissolved zinc concentration, irrespective of the zinc source tested (ZnCl2 and ZnO). Moreover, the addition of dissolved zinc counteracts the inhibiting effect of dissolved sulfate on dolomite formation. Integration with previous studies enables us to develop an understanding of the dolomitization pathway. Our findings suggest that the fluids’ high ionic strength and zinc complexation facilitate magnesium ion dehydration, resulting in a dramatic decrease in induction time. This study establishes a previously unrecognized role of zinc in dolomite formation, and may help explain the changes in dolomite abundance through geological time.