bluuebunny/crossref_metadata_2025_split huggingface dataset:
The world’s largest High Arctic lake responds rapidly to climate warming
Authors: Lehnherr Igor , St. Louis Vincent L. , Sharp Martin , Gardner Alex S. , Smol John P. , Schiff Sherry L. , Muir Derek C. G. , Mortimer Colleen A. , Michelutti Neil , Tarnocai Charles , St. Pierre Kyra A. , Emmerton Craig A. , Wiklund Johan A. , Köck Günter , Lamoureux Scott F. , Talbot Charles H. 
Published: April 2018

AbstractUsing a whole-watershed approach and a combination of historical, contemporary, modeled and paleolimnological datasets, we show that the High Arctic’s largest lake by volume (Lake Hazen) has succumbed to climate warming with only a ~1 °C relative increase in summer air temperatures. This warming deepened the soil active layer and triggered large mass losses from the watershed’s glaciers, resulting in a ~10 times increase in delivery of glacial meltwaters, sediment, organic carbon and legacy contaminants to Lake Hazen, a >70% decrease in lake water residence time, and near certainty of summer ice-free conditions. Concomitantly, the community assemblage of diatom primary producers in the lake shifted dramatically with declining ice cover, from shoreline benthic to open-water planktonic species, and the physiological condition of the only fish species in the lake, Arctic Char, declined significantly. Collectively, these changes place Lake Hazen in a biogeochemical, limnological and ecological regime unprecedented within the past ~300 years.
Biosynthesis of fragin is controlled by a novel quorum sensing signal
Authors: Jenul Christian , Sieber Simon , Daeppen Christophe , Mathew Anugraha , Lardi Martina , Pessi Gabriella , Hoepfner Dominic , Neuburger Markus , Linden Anthony , Gademann Karl , Eberl Leo 
Published: April 2018

AbstractMembers of the diazeniumdiolate class of natural compounds show potential for drug development because of their antifungal, antibacterial, antiviral, and antitumor activities. Yet, their biosynthesis has remained elusive to date. Here, we identify a gene cluster directing the biosynthesis of the diazeniumdiolate compound fragin in Burkholderia cenocepacia H111. We provide evidence that fragin is a metallophore and that metal chelation is the molecular basis of its antifungal activity. A subset of the fragin biosynthetic genes is involved in the synthesis of a previously undescribed cell-to-cell signal molecule, valdiazen. RNA-Seq analyses reveal that valdiazen controls fragin biosynthesis and affects the expression of more than 100 genes. Homologs of the valdiazen biosynthesis genes are found in various bacteria, suggesting that valdiazen-like compounds may constitute a new class of signal molecules. We use structural information, in silico prediction of enzymatic functions and biochemical data to propose a biosynthesis route for fragin and valdiazen.
Towards an arthritis flare-responsive drug delivery system
Authors: Joshi Nitin , Yan Jing , Levy Seth , Bhagchandani Sachin , Slaughter Kai V. , Sherman Nicholas E. , Amirault Julian , Wang Yufeng , Riegel Logan , He Xueyin , Rui Tan Shi , Valic Michael , Vemula Praveen K. , Miranda Oscar R. , Levy Oren , Gravallese Ellen M. , Aliprantis Antonios O. , Ermann Joerg , Karp Jeffrey M. 
Published: April 2018

AbstractLocal delivery of therapeutics for the treatment of inflammatory arthritis (IA) is limited by short intra-articular half-lives. Since IA severity often fluctuates over time, a local drug delivery method that titrates drug release to arthritis activity would represent an attractive paradigm in IA therapy. Here we report the development of a hydrogel platform that exhibits disassembly and drug release controlled by the concentration of enzymes expressed during arthritis flares. In vitro, hydrogel loaded with triamcinolone acetonide (TA) releases drug on-demand upon exposure to enzymes or synovial fluid from patients with rheumatoid arthritis. In arthritic mice, hydrogel loaded with a fluorescent dye demonstrates flare-dependent disassembly measured as loss of fluorescence. Moreover, a single dose of TA-loaded hydrogel but not the equivalent dose of locally injected free TA reduces arthritis activity in the injected paw. Together, our data suggest flare-responsive hydrogel as a promising next-generation drug delivery approach for the treatment of IA.
Infused ice can multiply IceCube’s sensitivity
Authors: Bartos Imre , Marka Zsuzsa , Marka Szabolcs 
Published: April 2018

AbstractThe IceCube Neutrino Observatory is the world’s largest neutrino detector with a cubic-kilometer instrumented volume at the South Pole. It is preparing for a major upgrade that will significantly increase its sensitivity. A promising technological innovation investigated for this upgrade is wavelength shifting optics. Augmenting sensors with such optics could increase the photo-collection area of IceCube’s digital optical modules, and shift the incoming photons’ wavelength to where these modules are the most sensitive. Here we investigate the use of IceCube’s drill holes as wavelength shifting optics. We calculate the sensitivity enhancement due to increasing the ice’s refractive index in the holes, and infusing wavelength-shifting substrate into the ice. We find that, with adequate wavelength-shifter infusion, every ~0.05 increase in the ice’s refractive index will increase IceCube’s photon sensitivity by 100%, opening the possibility for the substantial, cost-effective expansion of IceCube’s reach.
Extraordinary pseudocapacitive energy storage triggered by phase transformation in hierarchical vanadium oxides
Authors: Liu Bo-Tian , Shi Xiang-Mei , Lang Xing-You , Gu Lin , Wen Zi , Zhao Ming , Jiang Qing 
Published: April 2018

AbstractPseudocapacitance holds great promise for improving energy densities of electrochemical supercapacitors, but state-of-the-art pseudocapacitive materials show capacitances far below their theoretical values and deliver much lower levels of electrical power than carbon-based materials due to poor cation accessibility and/or long-range electron transferability. Here we show that in situ corundum-to-rutile phase transformation in electron-correlated vanadium sesquioxide can yield nonstoichiometric rutile vanadium dioxide layers that are composed of highly sodium ion accessible oxygen-deficiency quasi-hexagonal tunnels sandwiched between conductive rutile slabs. This unique structure serves to boost redox and intercalation kinetics for extraordinary pseudocapacitive energy storage in hierarchical isomeric vanadium oxides, leading to a high specific capacitance of ~1856 F g–1 (almost sixfold that of the pristine vanadium sesquioxide and dioxide) and a bipolar charge/discharge capability at ultrafast rates in aqueous electrolyte. Symmetric wide voltage window pseudocapacitors of vanadium oxides deliver a power density of ~280 W cm–3 together with an exceptionally high volumetric energy density of ~110 mWh cm–3 as well as long-term cycling stability.
Dual-comb spectroscopy of laser-induced plasmas
Authors: Bergevin Jenna , Wu Tsung-Han , Yeak Jeremy , Brumfield Brian E. , Harilal Sivanandan S. , Phillips Mark C. , Jones R. Jason 
Published: April 2018

AbstractDual-comb spectroscopy has become a powerful spectroscopic technique in applications that rely on its broad spectral coverage combined with high frequency resolution capabilities. Experiments to date have primarily focused on detection and analysis of multiple gas species under semi-static conditions, with applications ranging from environmental monitoring of greenhouse gases to high-resolution molecular spectroscopy. Here, we utilize dual-comb spectroscopy to demonstrate broadband, high-resolution, and time-resolved measurements in a laser-induced plasma. As a demonstration, we simultaneously detect trace amounts of Rb and K in solid samples with a single laser ablation shot, with transitions separated by over 6 THz (13 nm) and spectral resolution sufficient to resolve isotopic and ground state hyperfine splittings of the Rb D2 line. This new spectroscopic approach offers the broad spectral coverage found in the powerful techniques of laser-induced breakdown spectroscopy (LIBS) while providing the high-resolution and accuracy of cw laser-based spectroscopies.
Burned forests impact water supplies
Authors: Hallema Dennis W. , Sun Ge , Caldwell Peter V. , Norman Steven P. , Cohen Erika C. , Liu Yongqiang , Bladon Kevin D. , McNulty Steven G. 
Published: April 2018

AbstractWildland fire impacts on surface freshwater resources have not previously been measured, nor factored into regional water management strategies. But, large wildland fires are increasing and raise concerns about fire impacts on potable water. Here we synthesize long-term records of wildland fire, climate, and river flow for 168 locations across the United States. We show that annual river flow changed in 32 locations, where more than 19% of the basin area was burned. Wildland fires enhanced annual river flow in the western regions with a warm temperate or humid continental climate. Wildland fires increased annual river flow most in the semi-arid Lower Colorado region, in spite of frequent droughts in this region. In contrast, prescribed burns in the subtropical Southeast did not significantly alter river flow. These extremely variable outcomes offer new insights into the potential role of wildfire and prescribed fire in regional water resource management, under a changing climate.
Rolling up transition metal dichalcogenide nanoscrolls via one drop of ethanol
Authors: Cui Xueping , Kong Zhizhi , Gao Enlai , Huang Dazhen , Hao Yang , Shen Hongguang , Di Chong-an , Xu Zhiping , Zheng Jian , Zhu Daoben 
Published: April 2018

AbstractTwo-dimensional transition metal dichalcogenides (TMDs) have attracted lots of interest because of their potential for electronic and optoelectronic applications. Atomically thin TMD flakes were believed capable to scroll into nanoscrolls (NSs) with distinct properties. However, limited by mechanical strength and chemical stability, production of high-quality TMD NSs remains challenging. Here, we scroll chemical vapor deposition-grown monolayer TMD flakes into high-quality NSs in situ in 5 s with a nearly 100% yield by only one droplet of ethanol solution. An obvious photoluminescence is demonstrated in NSs and the self-encapsulated structure makes NSs more insensitive to external factors in optical and electrical properties. Furthermore, based on the internal open topology, NSs hybridized with a variety of functional materials have been fabricated, which is expected to confer TMD NSs with additional properties and functions attractive for potential application.
Endocycle-related tubular cell hypertrophy and progenitor proliferation recover renal function after acute kidney injury
Authors: Lazzeri Elena , Angelotti Maria Lucia , Peired Anna , Conte Carolina , Marschner Julian A. , Maggi Laura , Mazzinghi Benedetta , Lombardi Duccio , Melica Maria Elena , Nardi Sara , Ronconi Elisa , Sisti Alessandro , Antonelli Giulia , Becherucci Francesca , De Chiara Letizia , Guevara Ricardo Romero , Burger Alexa , Schaefer Beat , Annunziato Francesco , Anders Hans-Joachim , Lasagni Laura , Romagnani Paola 
Published: April 2018

AbstractAcute kidney injury (AKI) is considered largely reversible based on the capacity of surviving tubular cells to dedifferentiate and replace lost cells via cell division. Here we show by tracking individual tubular cells in conditional Pax8/Confetti mice that kidney function is recovered after AKI despite substantial tubular cell loss. Cell cycle and ploidy analysis upon AKI in conditional Pax8/FUCCI2aR mice and human biopsies identify endocycle-mediated hypertrophy of tubular cells. By contrast, a small subset of Pax2+ tubular progenitors enriches via higher stress resistance and clonal expansion and regenerates necrotic tubule segments, a process that can be enhanced by suitable drugs. Thus, renal functional recovery upon AKI involves remnant tubular cell hypertrophy via endocycle and limited progenitor-driven regeneration that can be pharmacologically enhanced.
Small molecules promote CRISPR-Cpf1-mediated genome editing in human pluripotent stem cells
Authors: Ma Xiaojie , Chen Xi , Jin Yan , Ge Wenyan , Wang Weiyun , Kong Linghao , Ji Junfang , Guo Xing , Huang Jun , Feng Xin-Hua , Fu Junfen , Zhu Saiyong 
Published: April 2018

AbstractHuman pluripotent stem cells (hPSCs) have potential applications in biological studies and regenerative medicine. However, precise genome editing in hPSCs remains time-consuming and labor-intensive. Here we demonstrate that the recently identified CRISPR-Cpf1 can be used to efficiently generate knockout and knockin hPSC lines. The unique properties of CRISPR-Cpf1, including shorter crRNA length and low off-target activity, are very attractive for many applications. In particular, we develop an unbiased drug-selection-based platform feasible for high-throughput screening in hPSCs and this screening system enables us to identify small molecules VE-822 and AZD-7762 that can promote CRISPR-Cpf1-mediated precise genome editing. Significantly, the combination of CRISPR-Cpf1 and small molecules provides a simple and efficient strategy for precise genome engineering.
Systematic design and experimental demonstration of bianisotropic metasurfaces for scattering-free manipulation of acoustic wavefronts
Authors: Li Junfei , Shen Chen , Díaz-Rubio Ana , Tretyakov Sergei A. , Cummer Steven A. 
Published: April 2018

AbstractRecent advances in gradient metasurfaces have shown that by locally controlling the bianisotropic response of the cells one can ensure full control of refraction, that is, arbitrarily redirect the waves without scattering into unwanted directions. In this work, we propose and experimentally verify the use of an acoustic cell architecture that provides enough degrees of freedom to fully control the bianisotropic response and minimizes the losses. The versatility of the approach is shown through the design of three refractive metasurfaces capable of redirecting a normally incident plane wave to 60°, 70°, and 80° on transmission. The efficiency of the bianisotropic designs is over 90%, much higher than the corresponding generalized Snell’s law based designs (81%, 58%, and 35%). The proposed strategy opens a new way of designing practical and highly efficient bianisotropic metasurfaces for different functionalities, enabling nearly ideal control over the energy flow through thin metasurfaces.
Structural mechanism for nucleotide-driven remodeling of the AAA-ATPase unfoldase in the activated human 26S proteasome
Authors: Zhu Yanan , Wang Wei Li , Yu Daqi , Ouyang Qi , Lu Ying , Mao Youdong 
Published: April 2018

AbstractThe proteasome is a sophisticated ATP-dependent molecular machine responsible for protein degradation in all known eukaryotic cells. It remains elusive how conformational changes of the AAA-ATPase unfoldase in the regulatory particle (RP) control the gating of the substrate–translocation channel leading to the proteolytic chamber of the core particle (CP). Here we report three alternative states of the ATP-γ-S-bound human proteasome, in which the CP gates are asymmetrically open, visualized by cryo-EM at near-atomic resolutions. At least four nucleotides are bound to the AAA-ATPase ring in these open-gate states. Variation in nucleotide binding gives rise to an axial movement of the pore loops narrowing the substrate-translation channel, which exhibit remarkable structural transitions between the spiral-staircase and saddle-shaped-circle topologies. Gate opening in the CP is thus regulated by nucleotide-driven conformational changes of the AAA-ATPase unfoldase. These findings demonstrate an elegant mechanism of allosteric coordination among sub-machines within the human proteasome holoenzyme.
Land-use change interacts with climate to determine elevational species redistribution
Authors: Guo Fengyi , Lenoir Jonathan , Bonebrake Timothy C. 
Published: April 2018

AbstractClimate change is driving global species redistribution with profound social and economic impacts. However, species movement is largely constrained by habitat availability and connectivity, of which the interaction effects with climate change remain largely unknown. Here we examine published data on 1464 elevational range shifts from 43 study sites to assess the confounding effect of land-use change on climate-driven species redistribution. We show that baseline forest cover and recent forest cover change are critical predictors in determining the magnitude of elevational range shifts. Forest loss positively interacts with baseline temperature conditions, such that forest loss in warmer regions tends to accelerate species’ upslope movement. Consequently, not only climate but also habitat loss stressors and, importantly, their synergistic effects matter in forecasting species elevational redistribution, especially in the tropics where both stressors will increase the risk of net lowland biotic attrition.
Crab spiders impact floral-signal evolution indirectly through removal of florivores
Authors: Knauer Anina C. , Bakhtiari Moe , Schiestl Florian P. 
Published: April 2018

AbstractThe puzzling diversity of flowers is primarily shaped by selection and evolutionary change caused by the plant’s interaction with animals. The contribution of individual animal species to net selection, however, may vary depending on the network of interacting organisms. Here we document that in the buckler mustard, Biscutella laevigata, the crab spider Thomisus onustus reduces bee visits to flowers but also benefits plants by feeding on florivores. Uninfested plants experience a trade-off between pollinator and spider attraction as both bees and crab spiders are attracted by the floral volatile β-ocimene. This trade-off is reduced by the induced emission of β-ocimene after florivore infestation, which is stronger in plant populations where crab spiders are present than where they are absent, suggesting that plants are locally adapted to the presence of crab spiders. Our study demonstrates the context-dependence of selection and shows how crab spiders impact on floral evolution.
Contraction of basal filopodia controls periodic feather branching via Notch and FGF signaling
Authors: Cheng Dongyang , Yan Xiaoli , Qiu Guofu , Zhang Juan , Wang Hanwei , Feng Tingting , Tian Yarong , Xu Haiping , Wang Meiqing , He Wanzhong , Wu Ping , Widelitz Randall B , Chuong Cheng-Ming , Yue Zhicao 
Published: April 2018

AbstractBranching morphogenesis is a general mechanism that increases the surface area of an organ. In chicken feathers, the flat epithelial sheath at the base of the follicle is transformed into periodic branches. How exactly the keratinocytes are organized into this pattern remains unclear. Here we show that in the feather follicle, the pre-branch basal keratinocytes have extensive filopodia, which contract and smooth out after branching. Manipulating the filopodia via small GTPases RhoA/Cdc42 also regulates branch formation. These basal filopodia help interpret the proximal-distal FGF gradient in the follicle. Furthermore, the topological arrangement of cell adhesion via E-Cadherin re-distribution controls the branching process. Periodic activation of Notch signaling drives the differential cell adhesion and contraction of basal filopodia, which occurs only below an FGF signaling threshold. Our results suggest a coordinated adjustment of cell shape and adhesion orchestrates feather branching, which is regulated by Notch and FGF signaling.
A high-strength silicide phase in a stainless steel alloy designed for wear-resistant applications
Authors: Bowden D. , Krysiak Y. , Palatinus L. , Tsivoulas D. , Plana-Ruiz S. , Sarakinou E. , Kolb U. , Stewart D. , Preuss M. 
Published: April 2018

AbstractHardfacing alloys provide strong, wear-resistant and corrosion-resistant coatings for extreme environments such as those within nuclear reactors. Here, we report an ultra-high-strength Fe–Cr–Ni silicide phase, named π-ferrosilicide, within a hardfacing Fe-based alloy. Electron diffraction tomography has allowed the determination of the atomic structure of this phase. Nanohardness testing indicates that the π-ferrosilicide phase is up to 2.5 times harder than the surrounding austenite and ferrite phases. The compressive strength of the π-ferrosilicide phase is exceptionally high and does not yield despite loading in excess of 1.6 GPa. Such a high-strength silicide phase could not only provide a new type of strong, wear-resistant and corrosion-resistant Fe-based coating, replacing more costly and hazardous Co-based alloys for nuclear applications, but also lead to the development of a new class of high-performance silicide-strengthened stainless steels, no longer reliant on carbon for strengthening.
Improved phase field model of dislocation intersections
Authors: Zheng Songlin , Zheng Dongchang , Ni Yong , He Linghui 
Published: April 2018

AbstractRevealing the long-range elastic interaction and short-range core reaction between intersecting dislocations is crucial to the understanding of dislocation-based strain hardening mechanisms in crystalline solids. Phase field model has shown great potential in modeling dislocation dynamics by both employing the continuum microelasticity theory to describe the elastic interactions and incorporating the γ-surface into the crystalline energy to enable the core reactions. Since the crystalline energy is approximately formulated by linear superposition of interplanar potential of each slip plane in the previous phase field model, it does not fully account for the reactions between dislocations gliding in intersecting slip planes. In this study, an improved phase field model of dislocation intersections is proposed through updating the crystalline energy by coupling the potential of two intersecting planes, and then applied to study the collinear interaction followed by comparison with the previous simulation result using discrete dislocation dynamics. Collinear annihilation captured only in the improved phase field model is found to strongly affect the junction formation and plastic flow in multislip systems. The results indicate that the improvement is essential for phase field model of dislocation intersections.
Functionalization of β-lactam antibiotic on lysozyme capped gold nanoclusters retrogress MRSA and its persisters following awakening
Authors: Kalita Sanjeeb , Kandimalla Raghuram , Bhowal Ashim Chandra , Kotoky Jibon , Kundu Sarathi 
Published: April 2018

AbstractIn this study we have reported an efficient antibacterial hybrid fabricated through surface functionalization of lysozyme capped gold nanoclusters (AUNC-L) with β-lactam antibiotic ampicillin (AUNC-L-Amp). The prepared hybrid not only reverted the MRSA resistance towards ampicillin but also demonstrated enhanced antibacterial activity against non-resistant bacterial strains. Most importantly, upon awakening through cis-2-decenoic acid (cis-DA) exposure, the MRSA persister got inhibited by the AUNC-L-Amp treatment. Intraperitoneal administration of this hybrid eliminates the systemic MRSA infection in a murine animal model. Topical application of this nano conjugate eradicated MRSA infection from difficult to treat diabetic wound of rat and accelerated the healing process. Due to inherent bio-safe nature of gold, AUNC-L alone or in the construct (AUNC-L-Amp) demonstrated excellent biocompatibility and did not indicate any deleterious effects in in vivo settings. We postulate that AUNC-L-Amp overcomes the elevated levels of β-lactamase at the site of MRSA antibiotic interaction with subsequent multivalent binding to the bacterial surface and enhanced permeation. Coordinated action of AUNC-L-Amp components precludes MRSA to attain resistance against the hybrid. We proposed that the inhibitory effect of AUNC-L-Amp against MRSA and its persister form is due to increased Amp concentration at the site of action, multivalent presentation and enhanced permeation of Amp through lysozyme-mediated cell wall lysis.