bluuebunny/crossref_metadata_2025_split huggingface dataset:
Topographic Expressions of Large Thrust Faults on Mars
Authors: Klimczak Christian , Kling Corbin L. , Byrne Paul K. 
Published: July 2018

AbstractOn planets with little erosion, thrust faults produce broad, asymmetric, positive‐relief, linear to arcuate ridges—often referred to as lobate scarps—that remain largely unaltered, such that their topographic expressions are a measure of the structural uplift caused by the displacement and associated country rock deformation of the faults. Here we map and systematically assess the structural relief of 24 thrust faults across Mars to infer their growth behavior. Our mapping indicates that the majority of individual thrust faults have simple, linear map traces with lengths of up to ~450 km but that some thrust faults form systems of up to 1,400 km in length. For the most topographically pronounced landforms, the structural relief developed above the fault is as great as ~3,400 m. We then relate topographic measurements to the displacement on the underlying fault planes to study the displacement variations along the fault length. We find a variety of displacement distribution shapes of the fault systems, which we attribute to differences in fault growth that include unrestricted and restricted growth, linkage, and/or fault interaction. Finally, we relate the maximum displacements (Dmax) determined for each of the faults to their respective fault length (L) to establish a maximum displacement‐to‐length relationship. The observed scaling characteristics and order‐of‐magnitude scatter of our Dmax/L data are not uncommon for fault populations on Earth and tie in well with the map patterns, tectonic geomorphology, and systematic along‐strike displacement distributions to have grown in a basement‐block faulting style found in intraplate tectonic settings on Earth.
Characterization of Hydrogen in Basaltic Materials With Laser‐Induced Breakdown Spectroscopy (LIBS) for Application to MSL ChemCam Data
Authors: Thomas N. H. , Ehlmann B. L. , Anderson D. E. , Clegg S. M. , Forni O. , Schröder S. , Rapin W. , Meslin P.‐Y. , Lasue J. , Delapp D. M. , Dyar M. D. , Gasnault O. , Wiens R. C. , Maurice S. 
Published: July 2018

AbstractThe Mars Science Laboratory rover, Curiosity, is equipped with ChemCam, a laser‐induced breakdown spectroscopy (LIBS) instrument, to determine the elemental composition of nearby targets quickly and remotely. We use a laboratory sample set including prepared mixtures of basalt with systematic variation in hydrated mineral content and compositionally well‐characterized, altered basaltic volcanic rocks to measure hydrogen by characterizing the H‐alpha emission line in LIBS spectra under Martian environmental conditions. The H contents of all samples were independently measured using thermogravimetric analysis. We found that H peak area increases with weight percent H for our laboratory mixtures with basaltic matrices. The increase is linear with weight percent H in the mixtures with structurally bound H up to about 1.25 wt.% H and then steepens for higher H‐content samples, a nonlinear trend not previously reported but potentially important for characterizing high water content materials. To compensate for instrument, environmental, and target matrix‐related effects on quantification of H content from the LIBS signal, we examined multiple normalization methods. The best performing methods utilize O 778‐ and C 248‐nm emission lines. The methods return comparable results when applied to ChemCam data of H‐bearing materials on Mars. The calibration and normalization methods tested here will aid in investigations of H by LIBS on Mars with ChemCam and SuperCam. Further laboratory work will aid quantification across different physical matrices and heterogeneous textures because of differences we observed in H in pelletized and natural rock samples of the same composition.
Seismotectonics of the Tajik Basin and Surrounding Mountain Ranges
Authors: Kufner Sofia‐Katerina , Schurr Bernd , Ratschbacher Lothar , Murodkulov Shohrukh , Abdulhameed Sanaa , Ischuk Anatoly , Metzger Sabrina , Kakar Najibullah 
Published: July 2018

AbstractSeismologic and geologic fault‐slip data characterize the active deformation of the intramontane Tajik basin and its margins, the Tian Shan, Pamir, and Hindu Kush at the northwestern tip of the India‐Asia collision zone. Within this complexly deforming region, the Tajik basin lithosphere forms the backstop for the north‐dipping Indian‐slab subduction beneath the Hindu Kush but itself delaminates and retreats west and northward beneath the Pamir. Herein, we link crustal deformation to these lithosphere‐scale processes, using data from recently deployed seismic networks and geologic observations. Transpressive strike‐slip deformation dominates the bounding fault zones along the basin's northern and eastern margins. Seismicity is most intense in the Garm region/Peter I. range of the northeastern basin, where these bounding faults converge and gain a dominant thrust component. Within the basin, seismically and geologically derived P axes align with the ~W‐trending GPS velocity vectors. Seismicity is concentrated in and at the base of a southward deepening, ∼9–15‐km‐thick wedge. Seismic deformation at the basin's southern margin occurs beneath the Afghan platform, where deep crustal earthquakes likely trace the western end of the Hindu Kush subduction zone. Roughly NNE‐striking sinistral strike‐slip events outline the Hindu Kush‐Pamir transfer system, a zone of distributed shear in the crust overlying the transition of the two oppositely dipping slabs at subcrustal depths. Our observations suggest that crustal deformation in the Pamir and Hindu Kush links with lithosphere‐scale processes, whereas deformation in the basin is controlled by the westward gravitational collapse of the Pamir and the resultant basin inversion.
Reconciling Drivers of Seasonal Terminus Advance and Retreat at 13 Central West Greenland Tidewater Glaciers
Authors: Fried M. J. , Catania G. A. , Stearns L. A. , Sutherland D. A. , Bartholomaus T. C. , Shroyer E. , Nash J. 
Published: July 2018

AbstractThe majority of Greenland tidewater glaciers undergo a seasonal cycle in terminus position, characterized by wintertime advance and summertime retreat. Understanding mechanisms that control seasonal cycles can help elucidate how tidewater glaciers regulate dynamic ice loss on longer timescales. However, controls on terminus position are numerous and complex. To address this, we compare time series of satellite‐derived terminus positions for tidewater glaciers in central west Greenland with observations of environmental forcings, including runoff at the grounding line, mélange presence, and, where available, ocean temperature in the proglacial fjord. We show that for most glaciers, seasonal terminus positions are more sensitive to glacial runoff than mélange or ocean thermal forcing. The strength of this relationship differs for two end‐member glacier types in the region, defined by their terminus geometry and dominant calving style. First, we find a strong relationship between magnitudes of runoff and terminus retreat at tidewater glaciers with shallow grounding lines (<400 m) that calve primarily through small‐magnitude serac failures. At these glaciers, subglacial plumes drive submarine melt and locally enhance retreat, causing heterogeneous position change across the terminus and local embayments where seasonal terminus changes are largest. In contrast, deep termini susceptible to buoyant flexure retreat sporadically through full ice thickness calving events less dependent on runoff. While less common, these glaciers deliver larger ice fluxes to the ocean. With predicted surface melt increases and diminished mélange coverage in a warming climate, our results reveal the impact of environmental forcings on diverse tidewater glacier systems in the region.
Nanostructured fibers as a versatile photonic platform: radiative cooling and waveguiding through transverse Anderson localization
Authors: Shi Norman Nan , Tsai Cheng-Chia , Carter Michael J. , Mandal Jyotirmoy , Overvig Adam C. , Sfeir Matthew Y. , Lu Ming , Craig Catherine L. , Bernard Gary D. , Yang Yuan , Yu Nanfang 
Published: July 2018

AbstractBroadband high reflectance in nature is often the result of randomly, three-dimensionally structured materials. This study explores unique optical properties associated with one-dimensional nanostructures discovered in silk cocoon fibers of the comet moth, Argema mittrei. The fibers are populated with a high density of air voids randomly distributed across the fiber cross-section but are invariant along the fiber. These filamentary air voids strongly scatter light in the solar spectrum. A single silk fiber measuring ~50 μm thick can reflect 66% of incoming solar radiation, and this, together with the fibers’ high emissivity of 0.88 in the mid-infrared range, allows the cocoon to act as an efficient radiative-cooling device. Drawing inspiration from these natural radiative-cooling fibers, biomimetic nanostructured fibers based on both regenerated silk fibroin and polyvinylidene difluoride are fabricated through wet spinning. Optical characterization shows that these fibers exhibit exceptional optical properties for radiative-cooling applications: nanostructured regenerated silk fibers provide a solar reflectivity of 0.73 and a thermal emissivity of 0.90, and nanostructured polyvinylidene difluoride fibers provide a solar reflectivity of 0.93 and a thermal emissivity of 0.91. The filamentary air voids lead to highly directional scattering, giving the fibers a highly reflective sheen, but more interestingly, they enable guided optical modes to propagate along the fibers through transverse Anderson localization. This discovery opens up the possibility of using wild silkmoth fibers as a biocompatible and bioresorbable material for optical signal and image transport.
3D printed optics with nanometer scale surface roughness
Authors: Vaidya Nina , Solgaard Olav 
Published: July 2018

AbstractComplex optical devices including aspherical focusing mirrors, solar concentrator arrays, and immersion lenses were 3D printed using commercial technology and experimentally demonstrated by evaluating surface roughness and shape. The as-printed surfaces had surface roughness on the order of tens of microns. To improve this unacceptable surface quality for creating optics, a polymer smoothing technique was developed. Atomic force microscopy and optical profilometry showed that the smoothing technique reduced the surface roughness to a few nanometers, consistent with the requirements of high-quality optics, while tests of optical functionality demonstrated that the overall shapes were maintained so that near theoretically predicted operation was achieved. The optical surface smoothing technique is a promising approach towards using 3D printing as a flexible tool for prototyping and fabrication of miniaturized high-quality optics.
In vivo screening identifies GATAD2B as a metastasis driver in KRAS-driven lung cancer
Authors: Grzeskowiak Caitlin L. , Kundu Samrat T. , Mo Xiulei , Ivanov Andrei A. , Zagorodna Oksana , Lu Hengyu , Chapple Richard H. , Tsang Yiu Huen , Moreno Daniela , Mosqueda Maribel , Eterovic Karina , Fradette Jared J. , Ahmad Sumreen , Chen Fengju , Chong Zechen , Chen Ken , Creighton Chad J. , Fu Haian , Mills Gordon B. , Gibbons Don L. , Scott Kenneth L. 
Published: July 2018

AbstractGenetic aberrations driving pro-oncogenic and pro-metastatic activity remain an elusive target in the quest of precision oncology. To identify such drivers, we use an animal model of KRAS-mutant lung adenocarcinoma to perform an in vivo functional screen of 217 genetic aberrations selected from lung cancer genomics datasets. We identify 28 genes whose expression promoted tumor metastasis to the lung in mice. We employ two tools for examining the KRAS-dependence of genes identified from our screen: 1) a human lung cell model containing a regulatable mutant KRAS allele and 2) a lentiviral system permitting co-expression of DNA-barcoded cDNAs with Cre recombinase to activate a mutant KRAS allele in the lungs of mice. Mechanistic evaluation of one gene, GATAD2B, illuminates its role as a dual activity gene, promoting both pro-tumorigenic and pro-metastatic activities in KRAS-mutant lung cancer through interaction with c-MYC and hyperactivation of the c-MYC pathway.
Mechanical architecture and folding of E. coli type 1 pilus domains
Authors: Alonso-Caballero Alvaro , Schönfelder Jörg , Poly Simon , Corsetti Fabiano , De Sancho David , Artacho Emilio , Perez-Jimenez Raul 
Published: July 2018

AbstractUropathogenic Escherichia coli attach to tissues using pili type 1. Each pilus is composed by thousands of coiled FimA domains followed by the domains of the tip fibrillum, FimF-FimG-FimH. The domains are linked by non-covalent β-strands that must resist mechanical forces during attachment. Here, we use single-molecule force spectroscopy to measure the mechanical contribution of each domain to the stability of the pilus and monitor the oxidative folding mechanism of a single Fim domain assisted by periplasmic FimC and the oxidoreductase DsbA. We demonstrate that pilus domains bear high mechanical stability following a hierarchy by which domains close to the tip are weaker than those close to or at the pilus rod. During folding, this remarkable stability is achieved by the intervention of DsbA that not only forms strategic disulfide bonds but also serves as a chaperone assisting the folding of the domains.
Root exudate metabolites drive plant-soil feedbacks on growth and defense by shaping the rhizosphere microbiota
Authors: Hu Lingfei , Robert Christelle A. M. , Cadot Selma , Zhang Xi , Ye Meng , Li Beibei , Manzo Daniele , Chervet Noemie , Steinger Thomas , van der Heijden Marcel G. A. , Schlaeppi Klaus , Erb Matthias 
Published: July 2018

AbstractBy changing soil properties, plants can modify their growth environment. Although the soil microbiota is known to play a key role in the resulting plant-soil feedbacks, the proximal mechanisms underlying this phenomenon remain unknown. We found that benzoxazinoids, a class of defensive secondary metabolites that are released by roots of cereals such as wheat and maize, alter root-associated fungal and bacterial communities, decrease plant growth, increase jasmonate signaling and plant defenses, and suppress herbivore performance in the next plant generation. Complementation experiments demonstrate that the benzoxazinoid breakdown product 6-methoxy-benzoxazolin-2-one (MBOA), which accumulates in the soil during the conditioning phase, is both sufficient and necessary to trigger the observed phenotypic changes. Sterilization, fungal and bacterial profiling and complementation experiments reveal that MBOA acts indirectly by altering root-associated microbiota. Our results reveal a mechanism by which plants determine the composition of rhizosphere microbiota, plant performance and plant-herbivore interactions of the next generation.
CD32 expression is associated to T-cell activation and is not a marker of the HIV-1 reservoir
Authors: Badia Roger , Ballana Ester , Castellví Marc , García-Vidal Edurne , Pujantell Maria , Clotet Bonaventura , Prado Julia G. , Puig Jordi , Martínez Miguel A. , Riveira-Muñoz Eva , Esté José A. 
Published: July 2018

AbstractCD32 has been shown to be preferentially expressed in latently HIV-1-infected cells in an in vitro model of quiescent CD4 T cells. Here we show that stimulation of CD4+ T cells with IL-2, IL-7, PHA, and anti-CD3/CD28 antibodies induces T-cell proliferation, co-expression of CD32 and the activation of the markers HLA-DR and CD69. HIV-1 infection increases CD32 expression. 79.2% of the CD32+/CD4+ T cells from HIV+ individuals under antiretroviral treatment were HLA-DR+. Resting CD4+ T cells infected in vitro generally results in higher integration of provirus. We observe no difference in provirus integration or replication-competent inducible latent HIV-1 in CD32+ or CD32− CD4+ T cells from HIV+ individuals. Our results demonstrate that CD32 expression is a marker of CD4+ T cell activation in HIV+ individuals and raises questions regarding the immune resting status of CD32+ cells harboring HIV-1 proviruses.
ZNF506-dependent positive feedback loop regulates H2AX signaling after DNA damage
Authors: Nowsheen Somaira , Aziz Khaled , Luo Kuntian , Deng Min , Qin Bo , Yuan Jian , Jeganathan Karthik B. , Yu Jia , Zhang Henan , Ding Wei , van Deursen Jan M. , Lou Zhenkun 
Published: July 2018

AbstractCells respond to cytotoxic DNA double-strand breaks by recruiting repair proteins to the damaged site. Phosphorylation of the histone variant H2AX at S139 and Y142 modulate its interaction with downstream DNA repair proteins and their recruitment to DNA lesions. Here we report ATM-dependent ZNF506 localization to the lesion through MDC1 following DNA damage. ZNF506, in turn, recruits the protein phosphatase EYA, resulting in dephosphorylation of H2AX at Y142, which further facilitates the recruitment of MDC1 and other downstream repair factors. Thus, ZNF506 regulates the early dynamic signaling in the DNA damage response (DDR) pathway and controls progressive downstream signal amplification. Cells lacking ZNF506 or harboring mutations found in cancer patient samples are more sensitive to radiation, offering a potential new therapeutic option for cancers with mutations in this pathway. Taken together, these results demonstrate how the DDR pathway is orchestrated by ZNF506 to maintain genomic integrity.
Gene expression drives the evolution of dominance
Authors: Huber Christian D. , Durvasula Arun , Hancock Angela M. , Lohmueller Kirk E. 
Published: July 2018

AbstractDominance is a fundamental concept in molecular genetics and has implications for understanding patterns of genetic variation, evolution, and complex traits. However, despite its importance, the degree of dominance in natural populations is poorly quantified. Here, we leverage multiple mating systems in natural populations ofArabidopsisto co-estimate the distribution of fitness effects and dominance coefficients of new amino acid changing mutations. We find that more deleterious mutations are more likely to be recessive than less deleterious mutations. Further, this pattern holds across gene categories, but varies with the connectivity and expression patterns of genes. Our work argues that dominance arises as a consequence of the functional importance of genes and their optimal expression levels.
Insulin/Snail1 axis ameliorates fatty liver disease by epigenetically suppressing lipogenesis
Authors: Liu Yan , Jiang Lin , Sun Chengxin , Ireland Nicole , Shah Yatrik M. , Liu Yong , Rui Liangyou 
Published: July 2018

AbstractInsulin stimulates lipogenesis but insulin resistance is also associated with increased hepatic lipogenesis in obesity. However, the underlying mechanism remains poorly characterized. Here, we show a noncanonical insulin-Snail1 pathway that suppresses lipogenesis. Insulin robustly upregulates zinc-finger protein Snail1 in a PI 3-kinase-dependent manner. In obesity, the hepatic insulin-Snail1 cascade is impaired due to insulin resistance. Hepatocyte-specific deletion of Snail1 enhances insulin-stimulated lipogenesis in hepatocytes, exacerbates dietary NAFLD in mice, and attenuates NAFLD-associated insulin resistance. Liver-specific overexpression of Snail1 has the opposite effect. Mechanistically, Snail1 binds to the fatty acid synthase promoter and recruits HDAC1/2 to induce deacetylation of H3K9 and H3K27, thereby repressing fatty acid synthase promoter activity. Our data suggest that insulin pathways bifurcate into canonical (lipogenic) and noncanonical (anti-lipogenesis by Snail1) two arms. The noncanonical arm counterbalances the canonical arm through Snail1-elicited epigenetic suppression of lipogenic genes. Impairment in the insulin-Snail1 arm may contribute to NAFLD in obesity.
Using machine learning and a data-driven approach to identify the small fatigue crack driving force in polycrystalline materials
Authors: Rovinelli Andrea , Sangid Michael D. , Proudhon Henry , Ludwig Wolfgang 
Published: July 2018

AbstractThe propagation of small cracks contributes to the majority of the fatigue lifetime for structural components. Despite significant interest, criteria for the growth of small cracks, in terms of the direction and speed of crack advancement, have not yet been determined. In this work, a new approach to identify the microstructurally small fatigue crack driving force is presented. Bayesian network and machine learning techniques are utilized to identify relevant micromechanical and microstructural variables that influence the direction and rate of the fatigue crack propagation. A multimodal dataset, combining results from a high-resolution 4D experiment of a small crack propagating in situ within a polycrystalline aggregate and crystal plasticity simulations, is used to provide training data. The relevant variables form the basis for analytical expressions thus representing the small crack driving force in terms of a direction and a rate equation. The ability of the proposed expressions to capture the observed experimental behavior is quantified and compared to the results directly from the Bayesian network and from fatigue metrics that are common in the literature. Results indicate that the direction of small crack propagation can be reliably predicted using the proposed analytical model and compares more favorably than other fatigue metrics.
Post-treatment with PT302, a long-acting Exendin-4 sustained release formulation, reduces dopaminergic neurodegeneration in a 6-Hydroxydopamine rat model of Parkinson’s disease
Authors: Chen Shuchun , Yu Seong-Jin , Li Yazhou , Lecca Daniela , Glotfelty Elliot , Kim Hee Kyung , Choi Ho-Il , Hoffer Barry J. , Greig Nigel H. , Kim Dong Seok , Wang Yun 
Published: July 2018

AbstractWe previously demonstrated that pretreatment with Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, reduces 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) –mediated dopaminergic neurodegeneration. The use of GLP-1 or Exendin-4 for Parkinson’s disease (PD) patients is limited by their short half-lives. The purpose of this study was to evaluate a new extended release Exendin-4 formulation, PT302, in a rat model of PD. Subcutaneous administration of PT302 resulted in sustained elevations of Exendin-4 in plasma for >20 days in adult rats. To define an efficacious dose within this range, rats were administered PT302 once every 2 weeks either before or following the unilaterally 6-hydroxydopamine lesioning. Pre- and post-treatment with PT302 significantly reduced methamphetamine–induced rotation after lesioning. For animals given PT302 post lesion, blood and brain samples were collected on day 47 for measurements of plasma Exendin-4 levels and brain tyrosine hydroxylase immunoreactivity (TH-IR). PT302 significantly increased TH-IR in the lesioned substantia nigra and striatum. There was a significant correlation between plasma Exendin-4 levels and TH-IR in the substantia nigra and striatum on the lesioned side. Our data suggest that post-treatment with PT302 provides long-lasting Exendin-4 release and reduces neurodegeneration of nigrostriatal dopaminergic neurons in a 6-hydroxydopamine rat model of PD at a clinically relevant dose.