bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensitivity of Labrador Sea Water Formation to Changes in Model Resolution, Atmospheric Forcing, and Freshwater Input
Authors: Garcia‐Quintana Yarisbel , Courtois Peggy , Hu Xianmin , Pennelly Clark , Kieke Dagmar , Myers Paul G. 
Published: March 2019

AbstractLabrador Sea Water (LSW) is one of the main contributors to the lower limb of the Atlantic Meridional Overturning Circulation. In this study, we explore the sensitivity of LSW formation to model resolution, Greenland melt, absence of high‐frequency atmospheric phenomena, and changes in precipitation. We use five numerical model simulations at both (1/4)° and (1/12)° resolutions. A kinematic subduction approach is used to obtain the LSW formation rate over the period 2004 to 2016. The control simulation, with (1/4)° resolution, showed a mean annual production rate of 1.9 Sv (1 Sv = 106 m3/s) in the density range of 27.68–27.80 kg/m3 for the period 2004–2016. Deep convection events that occurred during 2008, 2012, and 2014–2016 were captured. We found that with (1/4)° resolution the LSW formation rate is 19% larger compared with its counterpart at (1/12)° resolution. The presence of Greenland melt and an increase in the precipitation impact the denser LSW layer replenishment but do not decrease the overall LSW formation rate nor the maximum convection depth. A dramatic response was found when filtering the atmospheric forcing, which induced a decrease of 44% in heat loss over the Labrador Sea, strong enough to halt the deep convection and decrease the LSW formation rate by 89%. Even if our experiment was extreme, a decrease in the storms crossing the Labrador Sea with a consequent reduction in the winter heat loss might be a bigger threat to deep convection and LSW formation in the future than the expected increases in the freshwater input.
Meteoroids at the Moon: Orbital Properties, Surface Vaporization, and Impact Ejecta Production
Authors: Pokorný Petr , Janches Diego , Sarantos Menelaos , Szalay Jamey R. , Horányi Mihály , Nesvorný David , Kuchner Marc J. 
Published: March 2019

AbstractWe use a dynamical model to characterize the monthly and yearly variations of the lunar meteoroid environment for meteoroids originating from short and long‐period comets and the main‐belt asteroids. Our results show that if we assume the meteoroid mass flux of 43.3 tons per day at Earth, inferred from previous works, the mass flux of meteoroids impacting the Moon is 30 times smaller, approximately 1.4 tons per day, and shows variations of the order of 10% over a year. The mass flux difference is due to the combined effect of the smaller cross‐section of the Moon (factor of 13.46) and Earth's larger gravitational focusing (factor of 2–2.5). The lunar surface is vaporized by these impactors at an average impact vaporization flux of 11.6 × 10−16 g·cm−2·s−1, providing a significant source for the rarefied lunar exosphere. Our model predicts acceptable vaporization rates and reproduces the local time dependence of observations of the dust ejecta cloud, measured by the Lunar Dust Experiment on board NASA's Lunar Atmosphere and Dust Environment (LADEE) satellite. However, the predicted density of the lunar ejecta cloud is four orders of magnitude larger than reported values by LADEE. This discrepancy might be attributed to a much lower yield from meteoroid impacts on fluffy lunar regolith and/or a lower detection efficiency of the LADEE dust detector. We suggest an upper limit of 30 cm per million years for the soil gardening rate from small meteoroids.
Slip Rate Variation Along the Kunlun Fault (Tibet): Results From New GPS Observations and a Viscoelastic Earthquake‐Cycle Deformation Model
Authors: Diao Faqi , Xiong Xiong , Wang Rongjiang , Walter Thomas R. , Wang Yuebing , Wang Kai 
Published: March 2019

AbstractThe slip rate and its spatial variations of the Kunlun fault (KLF) play important roles in the tectonic evolution of the northeastern Tibetan Plateau. Here the slip rate of the Tuosuo Lake (TL) segment of the KLF, which remains controversial from various geological observations, is investigated with a dense Global Positioning System observation profile. With a viscoelastic earthquake‐cycle deformation model, the slip rate of the TL segment is estimated to be 5.5 ± 0.7 mm/a, in comparison with an overestimated value of 9.2 ± 1.1 mm/a from an elastic model. Combined with previous results, we infer that the slip rate of the KLF likely decreases gradually from the TL segment toward the eastern tip, rather than remaining uniform along the fault or decreasing rapidly within the easternmost 150 km. The estimated lower crust viscosity (~1018 Pa · s) agrees with values inferred from postseismic studies, which suggests a weak ductile lower crust in this region.
Widespread and Persistent Deposition of Iron Formations for Two Billion Years
Authors: Johnson Jena E. , Molnar Peter H. 
Published: March 2019

AbstractComposed of chemical precipitates rich in iron and silica, Precambrian iron formations from marine sedimentary records may reveal biogeochemical processes over the first half of Earth history. The limited record of early Archean rock suggests that preservation biases the iron formation record. Like ophiolites, which provide a sparse record of past ocean floor, iron formations deposited on oceanic crust ought to also be rare and preserved only when accreted onto cratons. To correct for potential preservation bias, we scaled masses of iron formations to the areal extent of basement rock of similar age and found that the resultant record is consistent with persistent deposition of iron formations across much of the deep ocean for two billion years. Widespread and long‐term iron formations imply that ferrous iron was available in the deep ocean for billions of years and that the requisite (bio)geochemical mechanisms to produce iron formations were present by 3.8 Ga.
S1PR1 regulates the switch of two angiogenic modes by VE-cadherin phosphorylation in breast cancer
Authors: Liu Shuang , Ni Chunsheng , Zhang Danfang , Sun Huizhi , Dong Xueyi , Che Na , Liang Xiaohui , Chen Chen , Liu Fang , Bai Jingru , Lin Xian , Zhao Xiulan , Sun Baocun 
Published: February 2019

AbstractAngiogenesis in solid tumors is divided into two modes: endothelium-dependent vessel (EDV) and vasculogenic mimicry (VM). Sphingosine-1-phosphate receptor 1 (S1PR1) plays a vital role on EDV in a variety of human tumors. However, the relationship between S1PR1 and VM is not clear. The aim of this study is to investigate S1PR1 on the regulation of EDV and mimicry formation in breast cancer. Here we show that S1PR1 phosphorylates the complex of VE-cadherin to regulate the switch of EDV and mimicry formation. Suppression of S1PR1 impairs EDV, but contributes to the generation of VM, invasion, and metastasis in vivo and vitro. By inhibiting RhoA activation, the S1PR1/VE-cadherin signaling is blocked. S1PR1 controls VE-cadherin expression and EDV via RhoA activation. Moreover, the low expression of S1PR1 correlates with VM and poor prognosis in breast cancer patient. The results show that S1PR1 regulated RhoA activation to accelerate VE-cadherin phosphorylation (Y731), leading to increased EDV and reduced VM in breast cancer. S1PR1 may provide a new thinking direction for antiangiogenic therapy for patients with breast cancer.
MTA2-mediated inhibition of PTEN leads to pancreatic ductal adenocarcinoma carcinogenicity
Authors: Si Wenzhe , Liu Xujun , Wei Rui , Zhang Yuan , Zhao Yang , Cui Liyan , Hong Tianpei 
Published: February 2019

AbstractMetastasis-associated protein 2 (MTA2) is a core subunit of the nucleosome remodeling and deacetylating (NuRD) complex and functions by mediating chromatin remodeling and gene silencing. However, its biological actions and clinical significance in pancreatic ductal adenocarcinoma (PDAC) remain elusive. The aim of this study was to explore the function and regulation mechanism of MTA2 in PDAC. As shown in GEO, ICGC, and TCGA databases, a higher expression of MTA2 was noticed in the PDAC tissues than in the normal pancreatic tissues. Moreover, a higher expression level of MTA2 was associated with a shorter overall survival time in these public PDAC databases. We further investigated the underlying mechanisms of these observations by using a chromatin immunoprecipitation (ChIP)-based deep sequencing, luciferase reporter, and quantitative ChIP assays. We identified the repressive binding of MTA2 to the promoter of phosphatase and tensin homolog (PTEN). We also found that Snail recruited MTA2 and HDAC1 to suppress PTEN expression. Ectopic expression and knockdown of MTA2 were performed to evaluate the effects of this gene on PDAC cell proliferation, migration, and invasion. Using CCK-8, colony formation and transwell assays, and a xenograft tumor model, we revealed that MTA2 promoted PDAC cell proliferation, migration, and invasion in vitro and PDAC tumor growth in vivo by downregulation of PTEN. In benzyl isothiocyanate (BITC)-treated MIA Paca-2 cells and PANC-1 cells, MTA2 level decreased in a dose- and time-dependent manner with concomitant upregulation of PTEN level and downregulation of phosphorylated PI3K and AKT levels, providing evidence of the involvement of MTA2 and PTEN in the regulation of the PI3K/AKT pathway in BITC-mediated PDAC suppression. Collectively, these findings uncover a novel role for MTA2 in the regulation of PDAC progression and help to elucidate the mechanisms involved in this process.
Long-term impact of maternal high-fat diet on offspring cardiac health: role of micro-RNA biogenesis
Authors: Siddeek Benazir , Mauduit Claire , Chehade Hassib , Blin Guillaume , Liand Marjorie , Chindamo Mariapia , Benahmed Mohamed , Simeoni Umberto 
Published: March 2019

AbstractHeart failure is a worldwide leading cause of death. Diet and obesity are particularly of high concern in heart disease etiology. Gravely, altered nutrition during developmental windows of vulnerability can have long-term impact on heart health; however, the underlying mechanisms are poorly understood. In the understanding of the initiation of chronic diseases related to developmental exposure to environmental challenges, deregulations in epigenetic mechanisms including micro-RNAs have been proposed as key events. In this context, we aimed at delineating the role of micro-RNAs in the programming of cardiac alterations induced by early developmental exposure to nutritional imbalance. To reach our aim, we developed a human relevant model of developmental exposure to nutritional imbalance by maternally exposing rat to high-fat diet during gestation and lactation. In this model, offspring exposed to maternal high-fat diet developed cardiac hypertrophy and increased extracellular matrix depot compared to those exposed to chow diet. Microarray approach performed on cardiac tissue allowed the identification of a micro-RNA subset which was down-regulated in high-fat diet-exposed animals and which were predicted to regulate transforming growth factor-beta (TGFβ)-mediated remodeling. As indicated by in vitro approaches and gene expression measurement in the heart of our animals, decrease in DiGeorge critical region 8 (DGCR8) expression, involved in micro-RNA biogenesis, seems to be a critical point in the alterations of the micro-RNA profile and the TGFβ-mediated remodeling induced by maternal exposure to high-fat diet. Finally, increasing DGCR8 activity and/or expression through hemin treatment in vitro revealed its potential in the rescue of the pro-fibrotic phenotype in cardiomyocytes driven by DGCR8 decrease. These findings suggest that cardiac alterations induced by maternal exposure to high-fat diet is related to abnormalities in TGFβ pathway and associated with down-regulated micro-RNA processing. Our study highlighted DGCR8 as a potential therapeutic target for heart diseases related to early exposure to dietary challenge.
Degenerate conic anchoring and colloidal elastic dipole-hexadecapole transformations
Authors: Zhou Ye , Senyuk Bohdan , Zhang Rui , Smalyukh Ivan I. , de Pablo Juan J. 
Published: March 2019

AbstractThe defect structure associated with a colloid in a nematic liquid crystal is dictated by molecular orientation at the colloid surface. Perpendicular or parallel orientations to the surface lead to dipole-like or quadrupole-like defect structures. However, the so-called elastic hexadecapole discovered recently, has been assumed to result from a conic anchoring condition. In order to understand it at a fundamental level, a model for this anchoring is introduced here in the context of a Landau-de Gennes free energy functional. We investigate the evolution of defect configurations, as well as colloidal interactions, by tuning the preferred tilt angle (θe). The model predicts an elastic dipole whose stability decreases asθeincreases, along with a dipole-hexadecapole transformation, which are confirmed by our experimental observations. Taken together, our results suggest that previously unanticipated avenues may exist for design of self-assembled structures via control of tilt angle.
State-of-the-art global models underestimate impacts from climate extremes
Authors: Schewe Jacob , Gosling Simon N. , Reyer Christopher , Zhao Fang , Ciais Philippe , Elliott Joshua , Francois Louis , Huber Veronika , Lotze Heike K. , Seneviratne Sonia I. , van Vliet Michelle T. H. , Vautard Robert , Wada Yoshihide , Breuer Lutz , Büchner Matthias , Carozza David A. , Chang Jinfeng , Coll Marta , Deryng Delphine , de Wit Allard , Eddy Tyler D. , Folberth Christian , Frieler Katja , Friend Andrew D. , Gerten Dieter , Gudmundsson Lukas , Hanasaki Naota , Ito Akihiko , Khabarov Nikolay , Kim Hyungjun , Lawrence Peter , Morfopoulos Catherine , Müller Christoph , Müller Schmied Hannes , Orth René , Ostberg Sebastian , Pokhrel Yadu , Pugh Thomas A. M. , Sakurai Gen , Satoh Yusuke , Schmid Erwin , Stacke Tobias , Steenbeek Jeroen , Steinkamp Jörg , Tang Qiuhong , Tian Hanqin , Tittensor Derek P. , Volkholz Jan , Wang Xuhui , Warszawski Lila 
Published: March 2019

AbstractGlobal impact models represent process-level understanding of how natural and human systems may be affected by climate change. Their projections are used in integrated assessments of climate change. Here we test, for the first time, systematically across many important systems, how well such impact models capture the impacts of extreme climate conditions. Using the 2003 European heat wave and drought as a historical analogue for comparable events in the future, we find that a majority of models underestimate the extremeness of impacts in important sectors such as agriculture, terrestrial ecosystems, and heat-related human mortality, while impacts on water resources and hydropower are overestimated in some river basins; and the spread across models is often large. This has important implications for economic assessments of climate change impacts that rely on these models. It also means that societal risks from future extreme events may be greater than previously thought.
Genesis of electron deficient Pt1(0) in PDMS-PEG aggregates
Authors: Liu Kairui , Hou Guangjin , Mao Jingbo , Xu Zhanwei , Yan Peifang , Li Huixiang , Guo Xinwen , Bai Shi , Zhang Z. Conrad 
Published: March 2019

AbstractWhile numerous single atoms stabilized by support surfaces have been reported, the synthesis of in-situ reduced discrete metal atoms weakly coordinated and stabilized in liquid media is a more challenging goal. We report the genesis of mononuclear electron deficient Pt1(0) by reducing H2PtCl6 in liquid polydimethylsiloxane-polyethylene glycol (PDMS-PEG) (Pt1@PDMS-PEG). UV–Vis, far-IR, and X-ray photoelectron spectroscopies evidence the reduction of H2PtCl6. CO infrared, and 195Pt and 13C NMR spectroscopies provide strong evidence of Pt1(0), existing as a pseudo-octahedral structure of (R1OR2)2Pt(0)Cl2H2 (R1 and R2 are H, C, or Si groups accordingly). The weakly coordinated (R1OR2)2Pt(0)Cl2H2 structure and electron deficient Pt1(0) have been validated by comparing experimental and DFT calculated 195Pt NMR spectra. The H+ in protic state and the Cl− together resemble HCl as the weak coordination. Neutralization by a base causes the formation of Pt nanoparticles. The Pt1@PDMS-PEG shows ultrahigh activity in olefin hydrosilylation with excellent terminal adducts selectivity.
Thermochemiluminescent peroxide crystals
Authors: Schramm Stefan , Karothu Durga Prasad , Lui Nathan M. , Commins Patrick , Ahmed Ejaz , Catalano Luca , Li Liang , Weston James , Moriwaki Taro , Solntsev Kyril M. , Naumov Panče 
Published: March 2019

AbstractChemiluminescence, a process of transduction of energy stored within chemical bonds of ground-state reactants into light via high-energy excited intermediates, is known in solution, but has remained undetected in macroscopic crystalline solids. By detecting thermally induced chemiluminescence from centimeter-size crystals of an organic peroxide here we demonstrate direct transduction of heat into light by thermochemiluminescence of bulk crystals. Heating of crystals of lophine hydroperoxide to ~115 °C results in detectable emission of blue-green light with maximum at 530 nm with low chemiluminescent quantum yield [(2.1 ± 0.1) × 10‒7 E mol‒1]. Spectral comparison of the thermochemiluminescence in the solid state and in solution revealed that the solid-state thermochemiluminescence of lophine peroxide is due to emission from deprotonated lophine. With selected 1,2-dioxetane, endoperoxide and aroyl peroxide we also establish that the thermochemiluminescence is common for crystalline peroxides, with the color of the emitted light varying from blue to green to red.
SFPQ and NONO suppress RNA:DNA-hybrid-related telomere instability
Authors: Petti Eleonora , Buemi Valentina , Zappone Antonina , Schillaci Odessa , Broccia Pamela Veneziano , Dinami Roberto , Matteoni Silvia , Benetti Roberta , Schoeftner Stefan 
Published: March 2019

AbstractIn vertebrates, the telomere repeat containing long, non-coding RNA TERRA is prone to form RNA:DNA hybrids at telomeres. This results in the formation of R-loop structures, replication stress and telomere instability, but also contributes to alternative lengthening of telomeres (ALT). Here, we identify the TERRA binding proteins NONO and SFPQ as novel regulators of RNA:DNA hybrid related telomere instability. NONO and SFPQ locate at telomeres and have a common role in suppressing RNA:DNA hybrids and replication defects at telomeres. NONO and SFPQ act as heterodimers to suppress fragility and homologous recombination at telomeres, respectively. Combining increased telomere fragility with unleashing telomere recombination upon NONO/SFPQ loss of function causes massive recombination events, involving 35% of telomeres in ALT cells. Our data identify the RNA binding proteins SFPQ and NONO as novel regulators at telomeres that collaborate to ensure telomere integrity by suppressing telomere fragility and homologous recombination triggered by RNA:DNA hybrids.
Dynamic pigmentary and structural coloration within cephalopod chromatophore organs
Authors: Williams Thomas L. , Senft Stephen L. , Yeo Jingjie , Martín-Martínez Francisco J. , Kuzirian Alan M. , Martin Camille A. , DiBona Christopher W. , Chen Chun-Teh , Dinneen Sean R. , Nguyen Hieu T. , Gomes Conor M. , Rosenthal Joshua J. C. , MacManes Matthew D. , Chu Feixia , Buehler Markus J. , Hanlon Roger T. , Deravi Leila F. 
Published: March 2019

AbstractChromatophore organs in cephalopod skin are known to produce ultra-fast changes in appearance for camouflage and communication. Light-scattering pigment granules within chromatocytes have been presumed to be the sole source of coloration in these complex organs. We report the discovery of structural coloration emanating in precise register with expanded pigmented chromatocytes. Concurrently, using an annotated squid chromatophore proteome together with microscopy, we identify a likely biochemical component of this reflective coloration as reflectin proteins distributed in sheath cells that envelop each chromatocyte. Additionally, within the chromatocytes, where the pigment resides in nanostructured granules, we find the lens protein Ω- crystallin interfacing tightly with pigment molecules. These findings offer fresh perspectives on the intricate biophotonic interplay between pigmentary and structural coloration elements tightly co-located within the same dynamic flexible organ - a feature that may help inspire the development of new classes of engineered materials that change color and pattern.
Rapid one-step 18F-radiolabeling of biomolecules in aqueous media by organophosphine fluoride acceptors
Authors: Hong Huawei , Zhang Lei , Xie Fang , Zhuang Rongqiang , Jiang Donglang , Liu Huanhuan , Li Jindian , Yang Hongzhang , Zhang Xianzhong , Nie Liming , Li Zijing 
Published: March 2019

AbstractCurrently, only a few 18F-radiolabeling methods were conducted in aqueous media, with non-macroelement fluoride acceptors and stringent conditions required. Herein, we describe a one-step non-solvent-biased, room-temperature-driven 18F-radiolabeling methodology based on organophosphine fluoride acceptors. The high water tolerance for this isotope-exchange-based 18F-labeling method is attributed to the kinetic and thermodynamic preference of F/F over the OH/F substitution based on computational calculations and experimental validation. Compact [18/19F]di-tert-butyl-organofluorophosphine and its derivatives used as 18F-labeling synthons exhibit excellent stability in vivo. The synthons are further conjugated to several biomolecular ligands such as c(RGDyk) and human serum albumin. The one-step labeled biomolecular tracers demonstrate intrinsic target imaging ability and negligible defluorination in vivo. The current method thus offers a facile and efficient 18F-radiolabeling pathway, enabling further widespread application of 18F.
Adhesive behavior and detachment mechanisms of bacterial amyloid nanofibers
Authors: Wang Ao , Keten Sinan 
Published: March 2019

AbstractAmyloid nanofibers, such as curli nanofibers, have proven capable of adhering strongly to abiotic surfaces. However, the adhesive performance of individual nanofibers and the dependence of this performance on physical properties remain to be characterized. We carried out coarse-grained molecular dynamics simulations to determine the detachment mechanisms of single amyloid fibers from surfaces. Taking a generic model inspired from the curli nanofiber subunit CsgA, we discover that the amyloid nanofibers can undergo three different peeling processes when pulled at a constant rate normal to the surface. Computational phase diagrams built from parametric studies indicate that strong nanofibers with high cohesive energy detach by peeling smoothly away from the substrate while weak fibers break prematurely. At intermediate ratios, hinge formation occurs and the work of peeling the nanofiber is twice the adhesive energy due to the additional energy required to bend the nanofiber during desorption. Varying the geometry of amyloid subunits revealed that the work of peeling decreases for thicker nanofibers, suggesting that the tape-like monomeric structure of amyloids may facilitate better adhesive performance. Our results demonstrate how the dimensions and adhesive and cohesive properties of the amyloid nanofibers can be optimized to resist mechanical peeling.