bluuebunny/crossref_metadata_2025_split huggingface dataset:
Artificial Aurora Produced by HAARP
Authors: Tulegenov B. , Streltsov A. V. , Kendall E. , McCarrick M. , Galkin I. 
Published: April 2019

AbstractWe present results from the ionospheric heating experiment conducted at the High Frequency Active Auroral Research Program (HAARP) facility, Alaska, on 12 March 2013. During the experiment, HAARP transmitted in the direction of the magnetic zenith X‐mode 4.57‐MHz wave. The transmitted power was modulated with the frequency of 0.9 mHz, and it was pointed on a 20‐km spot at the altitude of 120 km. The heating (1) generates disturbances in the magnetic field detected with the fluxgate magnetometer on the ground and (2) produces bright luminous spots in the ionosphere, observed with the HAARP telescope. Numerical simulations of the 3‐D reduced magnetohydrodynamic (MHD) model reveal that these effects can be related to the magnetic field‐aligned currents, excited in the ionosphere by changing the conductivity in the E region when the large‐scale electric field exists in the heating region.
Gravity Wave Ducting Observed in the Mesosphere Over Jicamarca, Peru
Authors: Lehmacher Gerald A. , Kudeki Erhan , Reyes Pablo M. , Lee Kiwook , Heale Christopher J. , Snively Jonathan B. 
Published: April 2019

AbstractShort‐period gravity waves are ubiquitous in the mesosphere, but the vertical structures of their perturbations are difficult to observe. The Jicamarca 50‐MHz very high frequency radar allows observations of winds and turbulent scatter with high temporal and vertical resolution. We present a case of a quasi‐monochromatic gravity wave with period 520 (±40) s that is likely ducted below a southward wind jet between 68 and 74 km. Above this layer of evanescence, a northward wind enables it to emerge into a more stable layer, where it is refracted to a short vertical wavelength of 2.2 (±0.2) km; data show evidence of weak nonlinearity, and possible overturning or partial reflection from higher altitudes, above the observable region, in the form of a standing wave structure in vertical velocity at approximately 75 km. Based on the dispersion relation, and with help of a two‐dimensional model, we determine that most likely the wave is propagating northward and is being ducted below and tunneling through the regions of evanescence created by the wind flow and typical mesospheric thermal structure. This is the first time that such an event has been identified in the Jicamarca mesospheric echoes, and it is distinct from Kelvin‐Helmholtz billows also commonly seen with this sensitive radar—instead apparently revealing tunneling of the gravity wave through ambient winds.
Large Fine‐Scale Spatiotemporal Variations of CH4 Diffusive Fluxes From Shrimp Aquaculture Ponds Affected by Organic Matter Supply and Aeration in Southeast China
Authors: Yang Ping , Zhang Yan , Yang Hong , Zhang Yifei , Xu Jin , Tan Lishan , Tong Chuan , Lai Derrick Y. F. 
Published: April 2019

AbstractMariculture shrimp ponds are important CH4 sources to the atmosphere. However, the spatiotemporal variations of CH4 concentration and flux at fine spatial scales in mariculture ponds are poorly known, particularly in China, worlds largest aquaculture producer. In this study, the plot‐scale spatiotemporal variations of water CH4 concentration and flux, both within and among ponds, were researched in shrimp ponds in Shanyutan wetland, Min River Estuary, Southeast China. The average water CH4 concentration and diffusion flux across the water‐air interface in the shrimp ponds over the shrimp aquaculture period varied from 2.29 ± 0.29 to 50.48 ± 20.91 μM and from 0.09 ± 0.01 to 2.32 ± 0.95 mmol·m−2·hr−1, respectively. The CH4 emissions from the estuarine ponds varied greatly between seasons, with peaks in August and September, which was similar to the trend of water temperature and dissolved oxygen concentrations. There was no remarkable difference in CH4 concentration and flux between shrimp ponds but significantly spatiotemporal differences in CH4 concentration and flux within the ponds. Significantly higher emissions occurred in the feeding zone, accounting for approximately 60% of total CH4 emission flux, while much lower CH4 emissions appeared in aeration zone, contributing 14% to total flux. This study suggests the importance of considering spatiotemporal variation in the whole‐pond estimates of CH4 concentration and flux. In light of such high spatial variation within ponds, improving aeration and feed utilization efficiency would help to mitigate CH4 emissions from mariculture ponds.
Atmospheric Nitrogen Deposition Increases the Possibility of Macroalgal Dominance on Remote Coral Reefs
Authors: Chen Xiaoyan , Yu Kefu , Huang Xueyong , Wang Yinghui , Liao Zhiheng , Zhang Ruijie , Yao Qiucui , Wang Jikun , Wang Wenhuan , Tao Shichen , Zhang Huiling 
Published: April 2019

AbstractField surveys in the Xisha and Zhongsha archipelagos, in the midnorthern South China Sea, show macroalgal dominance on remote reefs that were previously dominated by corals. This study was conducted to investigate the underlying mechanisms of this phenomenon. Benthic composition analyses indicated that macroalgae that are rare on pristine reefs dominated 27% of 81 study sites, and live coral cover dropped to 16.3% in 2015. Nearly one third of corals came into direct contact with macroalgae. Further analyses on the algal distribution patterns, nutrient fluxes, and air mass backward trajectories suggest that atmospheric nitrogen deposition is the major external supply of nutrients. The greater cover of macroalgae on the coral reefs coincides with the considerable atmospheric nitrogen deposition from the southwest during the summer monsoon. Moreover, the remote coral reefs hosted sevenfold greater macroalgae cover than the coastal coral reefs because atmospheric nitrogen assimilates effectively in the N limited and high visibility water. Macroalgae promotion is projected to grow with the increasing atmospheric nitrogen supply in the coming decade, which constitutes a larger stress on remote coral reefs.
Thermal plasticity of a freshwater cnidarian holobiont: detection of trans-generational effects in asexually reproducing hosts and symbionts
Authors: Ye Siao , Badhiwala Krishna N , Robinson Jacob T , Cho Won Hee , Siemann Evan 
Published: April 2019

Abstract
Understanding factors affecting the susceptibility of organisms to thermal stress is of enormous interest in light of our rapidly changing climate. When adaptation is limited, thermal acclimation and deacclimation abilities of organisms are critical for population persistence through a period of thermal stress. Holobionts (hosts plus associated symbionts) are key components of various ecosystems, such as coral reefs, yet the contributions of their two partners to holobiont thermal plasticity are poorly understood. Here, we tested thermal plasticity of the freshwater cnidarian Hydra viridissima (green hydra) using individual behavior and population responses. We found that algal presence initially reduced hydra thermal tolerance. Hydra with algae (symbiotic hydra) had comparable acclimation rates, deacclimation rates, and thermal tolerance after acclimation to those without algae (aposymbiotic hydra) but they had higher acclimation capacity. Acclimation of the host (hydra) and/or symbiont (algae) to elevated temperatures increased holobiont thermal tolerance and these effects persisted for multiple asexual generations. In addition, acclimated algae presence enhanced hydra fitness under prolonged sublethal thermal stress, especially when food was limited. Our study indicates while less intense but sublethal stress may favor symbiotic organisms by allowing them to acclimate, sudden large, potentially lethal fluctuations in climate stress likely favor aposymbiotic organisms. It also suggests that thermally stressed colonies of holobionts could disperse acclimated hosts and/or symbionts to other colonies, thereby reducing their vulnerability to climate change.
A clinically translatable hyperspectral endoscopy (HySE) system for imaging the gastrointestinal tract
Authors: Yoon Jonghee , Joseph James , Waterhouse Dale J. , Luthman A. Siri , Gordon George S. D. , di Pietro Massimiliano , Januszewicz Wladyslaw , Fitzgerald Rebecca C. , Bohndiek Sarah E. 
Published: April 2019

AbstractHyperspectral imaging (HSI) enables visualisation of morphological and biochemical information, which could improve disease diagnostic accuracy. Unfortunately, the wide range of image distortions that arise during flexible endoscopy in the clinic have made integration of HSI challenging. To address this challenge, we demonstrate a hyperspectral endoscope (HySE) that simultaneously records intrinsically co-registered hyperspectral and standard-of-care white light images, which allows image distortions to be compensated computationally and an accurate hyperspectral data cube to be reconstructed as the endoscope moves in the lumen. Evaluation of HySE performance shows excellent spatial, spectral and temporal resolution and high colour fidelity. Application of HySE enables: quantification of blood oxygenation levels in tissue mimicking phantoms; differentiation of spectral profiles from normal and pathological ex vivo human tissues; and recording of hyperspectral data under freehand motion within an intact ex vivo pig oesophagus model. HySE therefore shows potential for enabling HSI in clinical endoscopy.
Ceramides bind VDAC2 to trigger mitochondrial apoptosis
Authors: Dadsena Shashank , Bockelmann Svenja , Mina John G. M. , Hassan Dina G. , Korneev Sergei , Razzera Guilherme , Jahn Helene , Niekamp Patrick , Müller Dagmar , Schneider Markus , Tafesse Fikadu G. , Marrink Siewert J. , Melo Manuel N. , Holthuis Joost C. M. 
Published: April 2019

AbstractCeramides draw wide attention as tumor suppressor lipids that act directly on mitochondria to trigger apoptotic cell death. However, molecular details of the underlying mechanism are largely unknown. Using a photoactivatable ceramide probe, we here identify the voltage-dependent anion channels VDAC1 and VDAC2 as mitochondrial ceramide binding proteins. Coarse-grain molecular dynamics simulations reveal that both channels harbor a ceramide binding site on one side of the barrel wall. This site includes a membrane-buried glutamate that mediates direct contact with the ceramide head group. Substitution or chemical modification of this residue abolishes photolabeling of both channels with the ceramide probe. Unlike VDAC1 removal, loss of VDAC2 or replacing its membrane-facing glutamate with glutamine renders human colon cancer cells largely resistant to ceramide-induced apoptosis. Collectively, our data support a role of VDAC2 as direct effector of ceramide-mediated cell death, providing a molecular framework for how ceramides exert their anti-neoplastic activity.
Measured Canadian oil sands CO2 emissions are higher than estimates made using internationally recommended methods
Authors: Liggio John , Li Shao-Meng , Staebler Ralf M. , Hayden Katherine , Darlington Andrea , Mittermeier Richard L. , O’Brien Jason , McLaren Robert , Wolde Mengistu , Worthy Doug , Vogel Felix 
Published: April 2019

AbstractThe oil and gas (O&G) sector represents a large source of greenhouse gas (GHG) emissions globally. However, estimates of O&G emissions rely upon bottom-up approaches, and are rarely evaluated through atmospheric measurements. Here, we use aircraft measurements over the Canadian oil sands (OS) to derive the first top-down, measurement-based determination of the their annual CO2emissions and intensities. The results indicate that CO2emission intensities for OS facilities are 13–123% larger than those estimated using publically available data. This leads to 64% higher annual GHG emissions from surface mining operations, and 30% higher overall OS GHG emissions (17 Mt) compared to that reported by industry, despite emissions reporting which uses the most up to date and recommended bottom-up approaches. Given the similarity in bottom-up reporting methods across the entire O&G sector, these results suggest that O&G CO2emissions inventory data may be more uncertain than previously considered.
An inner activation gate controls TMEM16F phospholipid scrambling
Authors: Le Trieu , Jia Zhiguang , Le Son C. , Zhang Yang , Chen Jianhan , Yang Huanghe 
Published: April 2019

AbstractTransmembrane protein 16F (TMEM16F) is an enigmatic Ca2+-activated phospholipid scramblase (CaPLSase) that passively transports phospholipids down their chemical gradients and mediates blood coagulation, bone development and viral infection. Despite recent advances in the structure and function understanding of TMEM16 proteins, how mammalian TMEM16 CaPLSases open and close, or gate their phospholipid permeation pathways remains unclear. Here we identify an inner activation gate, which is established by three hydrophobic residues, F518, Y563 and I612, in the middle of the phospholipid permeation pathway of TMEM16F-CaPLSase. Disrupting the inner gate profoundly alters TMEM16F phospholipid permeation. Lysine substitutions of F518 and Y563 even lead to constitutively active CaPLSases that bypass Ca2+-dependent activation. Strikingly, an analogous lysine mutation to TMEM16F-F518 in TMEM16A (L543K) is sufficient to confer CaPLSase activity to the Ca2+-activated Cl− channel (CaCC). The identification of an inner activation gate can help elucidate the gating and permeation mechanism of TMEM16 CaPLSases and channels.
Spectra stable blue perovskite light-emitting diodes
Authors: Jiang Yuanzhi , Qin Chaochao , Cui Minghuan , He Tingwei , Liu Kaikai , Huang Yanmin , Luo Menghui , Zhang Li , Xu Hongyu , Li Saisai , Wei Junli , Liu Zhiyong , Wang Huanhua , Kim Gi-Hwan , Yuan Mingjian , Chen Jun 
Published: April 2019

AbstractDevice performance and in particular device stability for blue perovskite light-emitting diodes (PeLEDs) remain considerable challenges for the whole community. In this manuscript, we conceive an approach by tuning the ‘A-site’ cation composition of perovskites to develop blue-emitters. We herein report a Rubidium-Cesium alloyed, quasi-two-dimensional perovskite and demonstrate its great potential for pure-blue PeLED applications. Composition engineering and in-situ passivation are conducted to further improve the material’s emission property and stabilities. Consequently, we get a prominent film photoluminescence quantum yield of around 82% under low excitation density. Encouraged by these findings, we finally achieve a spectra-stable blue PeLED with the peak external quantum efficiency of 1.35% and a half-lifetime of 14.5 min, representing the most efficient and stable pure-blue PeLEDs reported so far. The strategy is also demonstrated to be able to generate efficient perovskite blue emitters and PeLEDs in the whole blue spectral region (from 454 to 492 nm).
A 3.8 Å resolution cryo-EM structure of a small protein bound to an imaging scaffold
Authors: Liu Yuxi , Huynh Duc T. , Yeates Todd O. 
Published: April 2019

AbstractProteins smaller than about 50 kDa are currently too small to be imaged at high resolution by cryo-electron microscopy (cryo-EM), leaving most protein molecules in the cell beyond the reach of this powerful structural technique. Here we use a designed protein scaffold to bind and symmetrically display 12 copies of a small 26 kDa protein, green fluorescent protein (GFP). We show that the bound cargo protein is held rigidly enough to visualize it at a resolution of 3.8 Å by cryo-EM, where specific structural features of the protein are visible. The designed scaffold is modular and can be modified through modest changes in its amino acid sequence to bind and display diverse proteins for imaging, thus providing a general method to break through the lower size limitation in cryo-EM.
Symbiotic cardiac pacemaker
Authors: Ouyang Han , Liu Zhuo , Li Ning , Shi Bojing , Zou Yang , Xie Feng , Ma Ye , Li Zhe , Li Hu , Zheng Qiang , Qu Xuecheng , Fan Yubo , Wang Zhong Lin , Zhang Hao , Li Zhou 
Published: April 2019

AbstractSelf-powered implantable medical electronic devices that harvest biomechanical energy from cardiac motion, respiratory movement and blood flow are part of a paradigm shift that is on the horizon. Here, we demonstrate a fully implanted symbiotic pacemaker based on an implantable triboelectric nanogenerator, which achieves energy harvesting and storage as well as cardiac pacing on a large-animal scale. The symbiotic pacemaker successfully corrects sinus arrhythmia and prevents deterioration. The open circuit voltage of an implantable triboelectric nanogenerator reaches up to 65.2 V. The energy harvested from each cardiac motion cycle is 0.495 μJ, which is higher than the required endocardial pacing threshold energy (0.377 μJ). Implantable triboelectric nanogenerators for implantable medical devices offer advantages of excellent output performance, high power density, and good durability, and are expected to find application in fields of treatment and diagnosis as in vivo symbiotic bioelectronics.
Sex-specific and pleiotropic effects underlying kidney function identified from GWAS meta-analysis
Authors: Graham Sarah E. , Nielsen Jonas B. , Zawistowski Matthew , Zhou Wei , Fritsche Lars G. , Gabrielsen Maiken E. , Skogholt Anne Heidi , Surakka Ida , Hornsby Whitney E. , Fermin Damian , Larach Daniel B. , Kheterpal Sachin , Brummett Chad M. , Lee Seunggeun , Kang Hyun Min , Abecasis Goncalo R. , Romundstad Solfrid , Hallan Stein , Sampson Matthew G. , Hveem Kristian , Willer Cristen J. 
Published: April 2019

AbstractChronic kidney disease (CKD) is a growing health burden currently affecting 10–15% of adults worldwide. Estimated glomerular filtration rate (eGFR) as a marker of kidney function is commonly used to diagnose CKD. We analyze eGFR data from the Nord-Trøndelag Health Study and Michigan Genomics Initiative and perform a GWAS meta-analysis with public summary statistics, more than doubling the sample size of previous meta-analyses. We identify 147 loci (53 novel) associated with eGFR, including genes involved in transcriptional regulation, kidney development, cellular signaling, metabolism, and solute transport. Additionally, sex-stratified analysis identifies one locus with more significant effects in women than men. Using genetic risk scores constructed from these eGFR meta-analysis results, we show that associated variants are generally predictive of CKD with only modest improvements in detection compared with other known clinical risk factors. Collectively, these results yield additional insight into the genetic factors underlying kidney function and progression to CKD.
Multi-level chirality in liquid crystals formed by achiral molecules
Authors: Salamończyk Mirosław , Vaupotič Nataša , Pociecha Damian , Walker Rebecca , Storey John M. D. , Imrie Corrie T. , Wang Cheng , Zhu Chenhui , Gorecka Ewa 
Published: April 2019

AbstractComplex materials often exhibit a hierarchical structure with an intriguing mechanism responsible for the ‘propagation’ of order from the molecular to the nano- or micro-scale level. In particular, the chirality of biological molecules such as nucleic acids and amino acids is responsible for the helical structure of DNA and proteins, which in turn leads to the lack of mirror symmetry of macro-bio-objects. To fully understand mechanisms of cross-level order transfer there is an intensive search for simpler artificial structures exhibiting hierarchical arrangement. Here we present complex systems built of achiral molecules that show four levels of structural chirality: layer chirality, helicity of a basic repeating unit, mesoscopic helix and helical filaments. The structures are identified by a combination of hard and soft x-ray diffraction measurements, optical studies and theoretical modelling. Similarly to many biological systems, the studied materials exhibit a coupling between chirality at different levels.
PIM kinases facilitate lentiviral evasion from SAMHD1 restriction via Vpx phosphorylation
Authors: Miyakawa Kei , Matsunaga Satoko , Yokoyama Masaru , Nomaguchi Masako , Kimura Yayoi , Nishi Mayuko , Kimura Hirokazu , Sato Hironori , Hirano Hisashi , Tamura Tomohiko , Akari Hirofumi , Miura Tomoyuki , Adachi Akio , Sawasaki Tatsuya , Yamamoto Naoki , Ryo Akihide 
Published: April 2019

AbstractLentiviruses have evolved to acquire an auxiliary protein Vpx to counteract the intrinsic host restriction factor SAMHD1. Although Vpx is phosphorylated, it remains unclear whether such phosphorylation indeed regulates its activity toward SAMHD1. Here we identify the PIM family of serine/threonine protein kinases as the factors responsible for the phosphorylation of Vpx and the promotion of Vpx-mediated SAMHD1 counteraction. Integrated proteomics and subsequent functional analysis reveal that PIM family kinases, PIM1 and PIM3, phosphorylate HIV-2 Vpx at Ser13 and stabilize the interaction of Vpx with SAMHD1 thereby promoting ubiquitin-mediated proteolysis of SAMHD1. Inhibition of the PIM kinases promotes the antiviral activity of SAMHD1, ultimately reducing viral replication. Our results highlight a new mode of virus–host cell interaction in which host PIM kinases facilitate promotion of viral infectivity by counteracting the host antiviral system, and suggest a novel therapeutic strategy involving restoration of SAMHD1-mediated antiviral response.
Porous metal-metalloporphyrin gel as catalytic binding pocket for highly efficient synergistic catalysis
Authors: Zhang Weijie , Dynes James J. , Hu Yongfeng , Jiang Pingping , Ma Shengqian 
Published: April 2019

AbstractSynergistic catalysis occurring in an enzyme pocket shows enhanced performance through supramolecular recognition and flexibility. This study presents an aerogel capable of similar function by fabricating a gel catalyst with hierarchical porosity. Here, the as-prepared Co-MMPG, a Co(II) metal-metalloporphyrin gel, maintains enough conformational flexibility and features a binding pocket formed from the co-facial arrangement of the porphyrin rings, as elucidated through the combined studies of solid-state NMR and X-ray absorption near-edge structure (XANES). The cooperativity between two Co(II) sites within the defined nanospace pocket facilitates the binding of different substrates with a favourable geometry thereby rendering Co-MMPG with excellent performance in the context of synergistic catalysis, especially for the kinetic control stereoselective reactions. Our work thus contributes a different enzyme-mimic design strategy to develop a highly efficient heterogeneous catalyst with high chemo/stereo selectivity.
BRD9 defines a SWI/SNF sub-complex and constitutes a specific vulnerability in malignant rhabdoid tumors
Authors: Wang Xiaofeng , Wang Su , Troisi Emma C. , Howard Thomas P. , Haswell Jeffrey R. , Wolf Bennett K. , Hawk William H. , Ramos Pilar , Oberlick Elaine M. , Tzvetkov Evgeni P. , Ross Aaron , Vazquez Francisca , Hahn William C. , Park Peter J. , Roberts Charles W. M. 
Published: April 2019

AbstractBromodomain-containing protein 9 (BRD9) is a recently identified subunit of SWI/SNF(BAF) chromatin remodeling complexes, yet its function is poorly understood. Here, using a genome-wide CRISPR-Cas9 screen, we show that BRD9 is a specific vulnerability in pediatric malignant rhabdoid tumors (RTs), which are driven by inactivation of the SMARCB1 subunit of SWI/SNF. We find that BRD9 exists in a unique SWI/SNF sub-complex that lacks SMARCB1, which has been considered a core subunit. While SMARCB1-containing SWI/SNF complexes are bound preferentially at enhancers, we show that BRD9-containing complexes exist at both promoters and enhancers. Mechanistically, we show that SMARCB1 loss causes increased BRD9 incorporation into SWI/SNF thus providing insight into BRD9 vulnerability in RTs. Underlying the dependency, while its bromodomain is dispensable, the DUF3512 domain of BRD9 is essential for SWI/SNF integrity in the absence of SMARCB1. Collectively, our results reveal a BRD9-containing SWI/SNF subcomplex is required for the survival of SMARCB1-mutant RTs.