bluuebunny/crossref_metadata_2025 huggingface dataset:
Arctic‐Boreal Lake Dynamics Revealed Using CubeSat Imagery
Authors: Cooley Sarah W. , Smith Laurence C. , Ryan Jonathan C. , Pitcher Lincoln H. , Pavelsky Tamlin M.
Published: February 2019

Fine‐scale, subseasonal fluctuations in Arctic‐Boreal surface water reflect regional water balance and modulate trace gas emissions to the atmosphere but have eluded detection using traditional satellite remote sensing. We use high‐resolution (~3–5 m), high‐frequency CubeSat sensors to measure near‐daily changes in lake surface area through an object‐based tracking method that incorporates machine learning to overcome notable limitations of CubeSat imagery. From ~76,000 images we obtain >2.2 million individual observations of changing surface areas for 85,358 lakes in Northern Canada and Alaska between 1 May and 1 October 2017. We find broad‐scale lake area declines across diverse climatic, hydrologic, and physiographic terrains. Localized exceptions reveal lowland flooding and aquatic vegetation phenology cycles. Cumulative small shoreline changes of abundant lakes on the Canadian Shield exceed total inundation variations of better‐studied lowland environments, revealing a surprisingly dynamic landscape with respect to subseasonal variations in surface water extent and trace gas emissions.
Seismic Constraints on the Magmatic System Beneath the Changbaishan Volcano: Insight Into its Origin and Regional Tectonics
Authors: Fan Xingli , Chen Qi‐Fu
Published: February 2019

There is a growing concern about the potential eruption of the Changbaishan volcano (CBV) in recent years, but the magmatic system beneath this volcano remains hotly debated. In this study, we construct a high‐resolution 3‐D crust and upper mantle S wave velocity (Vs) model beneath the CBV and adjacent regions combining ambient noise and earthquake surface wave tomography. Distinct low Vs anomalies are revealed in the crust and upper mantle beneath the CBV. The middle‐lower crustal low‐velocity body is interpreted to be the main magma chamber that may feed the surface volcanism and hydrothermal activities. The upper mantle low‐velocity zone is representative of upwelling asthenosphere. The lower crust beneath the Longgang volcano and Jingpohu volcano is also characterized by low Vs anomalies, maybe indicating low‐degree partial melting. We propose that the intraplate volcanism of the CBV as well as the Longgang volcano and Jingpohu volcano is driven by the decompression melting of upwelling asthenosphere, which could originate from the mantle transition zone as suggested by previous large‐scale tomographic studies. Moreover, the geologically identified Solonker‐Xar Moron‐Changchun‐Yanji suture zone is delineated by a prominent high Vs anomaly in the uppermost mantle, which may be explained by the fossil slab remnants or deformational fabrics resulted from the final closure of the Paleo‐Asian Ocean in the Late Paleozoic to Early Mesozoic.
Gravity Changes Due to Large Earthquakes Detected in GRACE Satellite Data via Empirical Orthogonal Function Analysis
Authors: Chao B. F. , Liau J. R.
Published: February 2019

We report on the seven largest earthquakes for which we can detect unequivocal coseismic signals in the time‐variable gravity (TVG) data of the GRACE (Gravity Recovery and Climate Experiment) satellite mission during the GRACE era of 2002–2017. After reducing the land‐hydrological effect according to model Global Land Data Assimilation System, we employ the empirical orthogonal function (EOF) analysis to solve for the spatial pattern and time history of the coherent (standing‐oscillation) modes, which provide in an objective manner an overall view of the spatiotemporal scenario. The solved EOF mode for an earthquake‐induced TVG typically features a spatial pattern (along with polarity) for the coseismic jump, in conjunction with the time series showing the jump (plus possible preseismic and postseismic variability). In all cases the earthquake EOF mode solutions match well with the least squares coseismic jump in both spatial pattern and amplitude and agree generally with previous reports in the literature. We conclude according to the examined cases that the lowest earthquake magnitude threshold that can be detected by GRACE is the Mw 8.3 of the 2013 deep‐focus Okhotsk event, which in fact provides a testable case where the TVG we observe versus the seismologically derived source models may reflect different aspects of the source mechanism under different timescales.
Processing Choices Affect Ocean Mass Estimates From GRACE
Authors: Uebbing B. , Kusche J. , Rietbroek R. , Landerer F. W.
Published: February 2019

Accurate estimates of ocean mass change are necessary to infer steric sea level change from sea level changes measured with satellite altimeters. Published studies using the Gravity Recovery and Climate Experiment (GRACE) satellite mission indicated a large range in trends (∼1–2 mm/year) with reported standard errors of 0.1–0.3 mm/year. Here we show that a large part of this discrepancy (up to 0.6 mm/year) can be explained by which model is used to account for the effect of glacial isostatic adjustment (GIA). The second largest contribution (0.3–0.4 mm/year) is related to the way how different studies have restored atmospheric and oceanic signals which have been removed during the GRACE gravity estimation process. Here two processing strategies, which previously resulted in differing ocean mass trends, are considered. The “direct” method uses the standard GRACE Stokes coefficients, while the “inverse” method applies a joint inversion of data from GRACE and altimetry. After accounting for differences in processing corrections, global mean ocean mass estimates from the direct, the mascon, and inverse approach agree with each other on global scales within less than 0.1 mm/year. Using the A et al. (2013; https://doi.org/10.1093/gji/ggs030) GIA model, we provide a reconciled monthly time series of global mean ocean mass, which suggests that ocean mass has increased by 1.43 mm/year over 2002.6–2014.5, with an amplified rate of 1.75 mm/year over 2002.6–2016.5 which covers almost the complete GRACE time span. However, we note that estimates as low as 1.05 mm/year cannot be ruled out when other published GIA corrections with lower mass‐equivalent signals over Antarctica are used.
A Game Theory Warning to Blind Drivers Playing Chicken With Public Goods
Authors: Ristić Bora , Madani Kaveh
Published: February 2019

We develop a game theoretic model of the role of foresight in games involving users interacting over a public good. Previous research in this area has applied game theory to understand social dilemmas and inform policy initiatives. However, considerations of the “evolving structure” of natural resource games over time and agents' planning horizon raises the complexity of game analysis substantially and has often been overlooked. We analyze a simple model of an irrigation system shared by two users and consider how players will act under different levels of foresight. Without foresight into game changes over time, players are blind to the fact that they are in a game of chicken. We model agents with foresight by interconnecting games across time and show how this creates opportunities for “strategic loss” early on, allowing players with foresight to reduce total costs. High future costs can thus be avoided with foresight if the rising costs of inaction are made apparent. We consider the effect of discounting and differences between players to provide policy recommendations regarding incentives for foresight.
Bioclimatic and Soil Moisture Monitoring Across Elevation in a Mountain Watershed: Opportunities for Research and Resource Management
Authors: Osenga E. C. , Arnott James C. , Endsley K. Arthur , Katzenberger J. W.
Published: February 2019

Soil moisture data are critical to understanding biophysical and societal impacts of climate change. However, soil moisture data availability is limited due to sparse in situ monitoring, particularly in mountain regions. Here we present methods, specifications, and initial results from the interactive Roaring Fork Observation Network (iRON), a soil, weather, and ecological monitoring system in the Southern Rocky Mountains of Colorado. Initiated in 2012, the network is currently composed of nine stations, distributed in elevation from 1,890 to 3,680 m, that continually collect and transmit measurements of soil moisture at three depths (5, 20, and 50 cm), soil temperature (20 cm), and meteorological conditions. Time‐lapse cameras for phenological observations, snow depth sensors, and periodic co‐located vegetation surveys complement selected stations. iRON was conceived and designed with the joint purpose of supporting bioclimatic research and resource management objectives in a snow‐dominated watershed. In the short term, iRON data can be applied to assessing the impact of temperature and precipitation on seasonal soil moisture conditions and trends. As more data are collected over time, iRON will help improve understanding of climate‐driven changes to soil, vegetation, and hydrologic conditions. In presenting this network and its initial data, we hope that the network's elevational gradient will contribute to bioclimatic mountain research, while active collaboration with partners in resource management may provide a model for science‐practice interaction in support of long‐term monitoring.
Author Correction: Post-traumatic stress disorder affects fucose-α(1–2)-glycans in the human brain: preliminary findings of neuro deregulation using in vivo two-dimensional neuro MR spectroscopy
Authors: Quadrelli Scott , Tosh Nathan , Urquhart Aaron , Trickey Katie , Tremewan Rosanna , Galloway Graham , Rich Lisa , Lea Rodney , Malycha Peter , Mountford Carolyn
Published: February 2019

The original article contained errors in the Fig. 1 caption. The incorrect sentence, “The region highlighted by the white box is expanded in Fig. 3” was corrected to, “The region highlighted by the white box is expanded in Fig. 2.” This has been corrected in the HTML and PDF of the article.
TGFβ/BMP immune signaling affects abundance and function of C. elegans gut commensals
Authors: Berg Maureen , Monnin David , Cho Juhyun , Nelson Lydia , Crits-Christoph Alex , Shapira Michael
Published: February 2019

The gut microbiota contributes to host health and fitness, and imbalances in its composition are associated with pathology. However, what shapes microbiota composition is not clear, in particular the role of genetic factors. Previous work in Caenorhabditis elegans defined a characteristic worm gut microbiota significantly influenced by host genetics. The current work explores the role of central regulators of host immunity and stress resistance, employing qPCR and CFU counts to measure abundance of core microbiota taxa in mutants raised on synthetic communities of previously-isolated worm gut commensals. This revealed a bloom, specifically of Enterobacter species, in immune-compromised TGFβ/BMP mutants. Imaging of fluorescently labeled Enterobacter showed that TGFβ/BMP-exerted control operated primarily in the anterior gut and depended on multi-tissue contributions. Enterobacter commensals are common in the worm gut, contributing to infection resistance. However, disruption of TGFβ/BMP signaling turned a normally beneficial Enterobacter commensal to pathogenic. These results demonstrate specificity in gene-microbe interactions underlying gut microbial homeostasis and highlight the pathogenic potential of their disruption.
A versatile functionalized ionic liquid to boost the solution-mediated performances of lithium-oxygen batteries
Authors: Zhang Jinqiang , Sun Bing , Zhao Yufei , Tkacheva Anastasia , Liu Zhenjie , Yan Kang , Guo Xin , McDonagh Andrew M. , Shanmukaraj Devaraj , Wang Chengyin , Rojo Teofilo , Armand Michel , Peng Zhangquan , Wang Guoxiu
Published: February 2019

Due to the high theoretical specific energy, the lithium–oxygen battery has been heralded as a promising energy storage system for applications such as electric vehicles. However, its large over-potentials during discharge–charge cycling lead to the formation of side-products, and short cycle life. Herein, we report an ionic liquid bearing the redox active 2,2,6,6-tetramethyl-1-piperidinyloxy moiety, which serves multiple functions as redox mediator, oxygen shuttle, lithium anode protector, as well as electrolyte solvent. The additive contributes a 33-fold increase of the discharge capacity in comparison to a pure ether-based electrolyte and lowers the over-potential to an exceptionally low value of 0.9 V. Meanwhile, its molecule facilitates smooth lithium plating/stripping, and promotes the formation of a stable solid electrolyte interface to suppress side-reactions. Moreover, the proportion of ionic liquid in the electrolyte influences the reaction mechanism, and a high proportion leads to the formation of amorphous lithium peroxide and a long cycling life (> 200 cycles). In particular, it enables an outstanding electrochemical performance when operated in air.
Versatile kit of robust nanoshapes self-assembling from RNA and DNA modules
Authors: Monferrer Alba , Zhang Douglas , Lushnikov Alexander J. , Hermann Thomas
Published: February 2019

DNA and RNA have emerged as a material for nanotechnology applications that take advantage of the nucleic acids’ ability to encode folding and programmable self-assembly through mainly base pairing. The two types of nucleic acid have rarely been used in combination to enhance structural diversity or for partitioning of functional and architectural roles. Here, we report a design and screening strategy to integrate combinations of RNA motifs as architectural joints and DNA building blocks as functional modules for programmable self-assembly of a versatile toolkit of polygonal nucleic acid nanoshapes. Clean incorporation of diverse DNA modules with various topologies attest to the extraordinary robustness of the RNA-DNA hybrid framework. The design and screening strategy enables systematic development of RNA-DNA hybrid nanoshapes as programmable platforms for applications in molecular recognition, sensor and catalyst development as well as protein interaction studies.
Identification and characterization of a direct activator of a gene transfer agent
Authors: Fogg Paul C. M.
Published: February 2019

Gene transfer agents (GTAs) are thought to be ancient bacteriophages that have been co-opted into serving their host and can now transfer any gene between bacteria. Production of GTAs is controlled by several global regulators through unclear mechanisms. In Rhodobacter capsulatus, gene rcc01865 encodes a putative regulatory protein that is essential for GTA production. Here, I show that rcc01865 (hereafter gafA) encodes a transcriptional regulator that binds to the GTA promoter to initiate production of structural and DNA packaging components. Expression of gafA is in turn controlled by the pleiotropic regulator protein CtrA and the quorum-sensing regulator GtaR. GafA and CtrA work together to promote GTA maturation and eventual release through cell lysis. Identification of GafA as a direct GTA regulator allows the first integrated regulatory model to be proposed and paves the way for discovery of GTAs in other species that possess gafA homologues.
Negative differential resistance as a critical indicator for the discharge capacity of lithium-oxygen batteries
Authors: Hase Yoko , Komori Yasuhiro , Kusumoto Takayoshi , Harada Takashi , Seki Juntaro , Shiga Tohru , Kamiya Kazuhide , Nakanishi Shuji
Published: February 2019

In non-aqueous lithium-oxygen batteries, the one-electron reduction of oxygen and subsequent lithium oxide formation both occur during discharge. This lithium oxide can be converted to insulating lithium peroxide via two different pathways: a second reduction at the cathode surface or disproportionation in solution. The latter process is known to be advantageous with regard to increasing the discharge capacity and is promoted by a high donor number electrolyte because of the stability of lithium oxide in media of this type. Herein, we report that the cathodic oxygen reduction reaction during discharge typically exhibits negative differential resistance. Importantly, the magnitude of negative differential resistance, which varies with the system component, and the position of the cathode potential relative to the negative differential resistance determined the reaction pathway and the discharge capacity. This result implies that the stability of lithium oxide on the cathode also contributes to the determination of the reaction pathway.
High-resolution spectroscopy of single nuclear spins via sequential weak measurements
Authors: Pfender Matthias , Wang Ping , Sumiya Hitoshi , Onoda Shinobu , Yang Wen , Dasari Durga Bhaktavatsala Rao , Neumann Philipp , Pan Xin-Yu , Isoya Junichi , Liu Ren-Bao , Wrachtrup Jörg
Published: February 2019

Nuclear magnetic resonance (NMR) of single spins have recently been detected by quantum sensors. However, the spectral resolution has been limited by the sensor’s relaxation to a few kHz at room temperature. This can be improved by using quantum memories, at the expense of sensitivity. In contrast, classical signals can be measured with exceptional spectral resolution by using continuous measurement techniques, without compromising sensitivity. When applied to single-spin NMR, it is critical to overcome the impact of back action inherent of quantum measurement. Here we report sequential weak measurements on a single 13C nuclear spin. The back-action causes the spin to undergo a quantum dynamics phase transition from coherent trapping to coherent oscillation. Single-spin NMR at room-temperature with a spectral resolution of 3.8 Hz is achieved. These results enable the use of measurement-correlation schemes for the detection of very weakly coupled single spins.
Cytoskeletal stiffening in synthetic hydrogels
Authors: de Almeida Paula , Jaspers Maarten , Vaessen Sarah , Tagit Oya , Portale Giuseppe , Rowan Alan E. , Kouwer Paul H. J.
Published: February 2019

Although common in biology, controlled stiffening of hydrogels in vitro is difficult to achieve; the required stimuli are commonly large and/or the stiffening amplitudes small. Here, we describe the hierarchical mechanics of ultra-responsive hybrid hydrogels composed of two synthetic networks, one semi-flexible and stress-responsive, the other flexible and thermoresponsive. Heating collapses the flexible network, which generates internal stress that causes the hybrid gel to stiffen up to 50 times its original modulus; an effect that is instantaneous and fully reversible. The average generated forces amount to ~1 pN per network fibre, which are similar to values found for stiffening resulting from myosin molecular motors in actin. The excellent control, reversible nature and large response gives access to many biological and bio-like applications, including tissue engineering with truly dynamic mechanics and life-like matter.
Craniometrics Reveal “Two Layers” of Prehistoric Human Dispersal in Eastern Eurasia
Authors: Matsumura Hirofumi , Hung Hsiao-chun , Higham Charles , Zhang Chi , Yamagata Mariko , Nguyen Lan Cuong , Li Zhen , Fan Xue-chun , Simanjuntak Truman , Oktaviana Adhi Agus , He Jia-ning , Chen Chung-yu , Pan Chien-kuo , He Gang , Sun Guo-ping , Huang Wei-jin , Li Xin-wei , Wei Xing-tao , Domett Kate , Halcrow Siân , Nguyen Kim Dung , Trinh Hoang Hiep , Bui Chi Hoang , Nguyen Khanh Trung Kien , Reinecke Andreas
Published: February 2019

This cranio-morphometric study emphasizes a “two-layer model” for eastern Eurasian anatomically modern human (AMH) populations, based on large datasets of 89 population samples including findings directly from ancient archaeological contexts. Results suggest that an initial “first layer” of AMH had related closely to ancestral Andaman, Australian, Papuan, and Jomon groups who likely entered this region via the Southeast Asian landmass, prior to 65–50 kya. A later “second layer” shared strong cranial affinities with Siberians, implying a Northeast Asian source, evidenced by 9 kya in central China and then followed by expansions of descendant groups into Southeast Asia after 4 kya. These two populations shared limited initial exchange, and the second layer grew at a faster rate and in greater numbers, linked with contexts of farming that may have supported increased population densities. Clear dichotomization between the two layers implies a temporally deep divergence of distinct migration routes for AMH through both southern and northern Eurasia.
A variant in the MICA gene is associated with liver fibrosis progression in chronic hepatitis C through TGF-β1 dependent mechanisms
Authors: Sharkawy Rasha El , Bayoumi Ali , Metwally Mayada , Mangia Alessandra , Berg Thomas , Romero-Gomez Manuel , Abate Maria Lorena , Irving William L. , Sheridan David , Dore Gregory J. , Spengler Ulrich , Lampertico Pietro , Bugianesi Elisabetta , Weltman Martin , Mollison Lindsay , Cheng Wendy , Riordan Stephen , Santoro Rosanna , Gallego-Durán Rocío , Fischer Janett , Nattermann Jacob , D’Ambrosio Roberta , McLeod Duncan , Powell Elizabeth , latchoumanin Olivier , Thabet Khaled , Najim Mustafa A. M. , Douglas Mark W. , Liddle Christopher , Qiao Liang , George Jacob , Eslam Mohammed ,   International Liver Disease Genetics Consortium (ILDGC), White Rose , Rojas Angela , Bassendine Margaret , Rosso Chiara , Mezzabotta Lavinia , Leung Reynold , Malik Barbara , Matthews Gail , Grebely Jason , Fragomeli Vincenzo , Jonsson Julie R.
Published: February 2019

Hepatocarcinogenesis is tightly linked to liver fibrosis. Recently, two GWAS variants, MICA rs2596542 and DEPDC5 rs1012068 were identified as being associated with the development of HCV-induced hepatocellular carcinoma (HCC) in Japanese patients. The role of these variants on hepatic inflammation and fibrosis that are closely associated with HCC development is not known, nor are the biological mechanisms underlying their impact on the liver. Here, we demonstrate in 1689 patients with chronic hepatitis C (CHC) (1,501 with CHC and 188 with HCV-related HCC), that the MICA (T) allele, despite not being associated with HCC susceptibility, is associated with increased fibrosis stage (OR: 1.47, 95% CI: 1.05–2.06, p = 0.02) and fibrosis progression rate (hazards ratio: 1.41, 95% CI: 1.04–1.90, p = 0.02). The DEPDC5 variant was not associated with any of these phenotypes. MICA expression was down-regulated in advanced fibrosis stages. Further, (T) allele carriage was associated with lower MICA expression in liver and serum. Transforming growth factor-β1 (TGF-β1) expression suppresses MICA expression in hepatic stellate cells. Our findings suggest a novel mechanism linking susceptibility to advanced fibrosis and subsequently indirectly to HCC, to the level of MICA expression through TGF-β1-dependent mechanisms.
Evolutionary dynamics of sexual size dimorphism in non-volant mammals following their independent colonization of Madagascar
Authors: Kappeler Peter M. , Nunn Charles L. , Vining Alexander Q. , Goodman Steven M.
Published: February 2019

As predicted by sexual selection theory, males are larger than females in most polygynous mammals, but recent studies found that ecology and life history traits also affect sexual size dimorphism (SSD) through evolutionary changes in either male size, female size, or both. The primates of Madagascar (Lemuriformes) represent the largest group of mammals without male-biased SSD. The eco-evo-devo hypothesis posited that adaptations to unusual climatic unpredictability on Madagascar have ultimately reduced SSD in lemurs after dispersing to Madagascar, but data have not been available for comparative tests of the corresponding predictions that SSD is also absent in other terrestrial Malagasy mammals and that patterns of SSD changed following the colonization of Madagascar. We used phylogenetic methods and new body mass data to test these predictions among the four endemic radiations of Malagasy primates, carnivorans, tenrecs, and rodents. In support of our prediction, we found that male-biased SSD is generally absent among all Malagasy mammals. Phylogenetic comparative analyses further indicated that after their independent colonization of Madagascar, SSD decreased in primates and tenrecs, but not in the other lineages or when analyzed across all species. We discuss several mechanisms that may have generated these patterns and conclude that neither the eco-evo-devo hypothesis, founder effects, the island rule nor sexual selection theory alone can provide a compelling explanation for the observed patterns of SSD in Malagasy mammals.
Decreased complexity of glucose dynamics in diabetes in rhesus monkeys
Authors: Raubertas Richard , Beech Jeremy , Watson Wendy , Fox Steven , Tiesma Scott , Gilberto David B. , Bone Ashleigh , Rebbeck Patricia A. , Gantert Liza T. , Conarello Stacey , Knapp Walter , Gray Tasha , Handt Larry , Li Cai
Published: February 2019

Until recently, preclinical and clinical work on diabetes has focused on the understanding of blood glucose elevation and its detrimental metabolic sequelae. The advent of continuous glucose monitoring (CGM) technology now allows real time monitoring of blood glucose levels as a time series, and thus the exploration of glucose dynamics at short time scales. Previous work has shown decreases in the complexity of glucose dynamics, as measured by multiscale entropy (MSE) analysis, in diabetes in humans, mice, and rats. Analyses for non-human primates (NHP) have not been reported, nor is it known if anti-diabetes compounds affect complexity of glucose dynamics. We instrumented four healthy and six diabetic rhesus monkeys with CGM probes in the carotid artery and collected glucose values at a frequency of one data point per second for the duration of the sensors’ life span. Sensors lasted between 45 and 78 days. Five of the diabetic rhesus monkeys were also administered the anti-diabetic drug liraglutide daily beginning at day 39 of the CGM monitoring period. Glucose levels fluctuated during the day in both healthy and diabetic rhesus monkeys, peaking between 12 noon – 6 pm. MSE analysis showed reduced complexity of glucose dynamics in diabetic monkeys compared to healthy animals. Although liraglutide decreased glucose levels, it did not restore complexity in diabetic monkeys consistently. Complexity varied by time of day, more strongly for healthy animals than for diabetic animals. And by dividing the monitoring period into 3-day or 1-week subperiods, we were able to estimate within-animal variability of MSE curves. Our data reveal that decreased complexity of glucose dynamics is a conserved feature of diabetes from rodents to NHPs to man.
Transport mechanism of deformable micro-gel particle through micropores with mechanical properties characterized by AFM
Authors: Lei Wenhai , Xie Chiyu , Wu Tianjiang , Wu Xingcai , Wang Moran
Published: February 2019

Deformable micro-gel particles (DMP) have been used to enhanced oil recovery (EOR) in reservoirs with unfavourable conditions. Direct pore-scale understanding of the DMP transport mechanism is important for further improvements of its EOR performance. To consider the interaction between soft particle and fluid in complex pore-throat geometries, we perform an Immersed Boundary-Lattice Boltzmann (IB-LB) simulation of DMP passing through a throat. A spring-network model is used to capture the deformation of DMP. In order to obtain appropriate simulation parameters that represent the real mechanical properties of DMP, we propose a procedure via fitting the DMP elastic modulus data measured by the nano-indentation experiments using Atomic Force Microscope (AFM). The pore-scale modelling obtains the critical pressure of the DMP for different particle-throat diameter ratios and elastic modulus. It is found that two-clog particle transport mode is observed in a contracted throat, the relationship between the critical pressure and the elastic modulus/particle-throat diameter ratio follows a power law. The particle-throat diameter ratio shows a greater impact on the critical pressure difference than the elastic modulus of particles.
The eastern extent of seasonal iron limitation in the high latitude North Atlantic Ocean
Authors: Birchill A. J. , Hartner N. T. , Kunde K. , Siemering B. , Daniels C. , González-Santana D. , Milne A. , Ussher S. J. , Worsfold P. J. , Leopold K. , Painter S. C. , Lohan M. C.
Published: February 2019

The availability of iron (Fe) can seasonally limit phytoplankton growth in the High Latitude North Atlantic (HLNA), greatly reducing the efficiency of the biological carbon pump. However, the spatial extent of seasonal iron limitation is not yet known. We present autumn nutrient and dissolved Fe measurements, combined with microphytoplankton distribution, of waters overlying the Hebridean (Scottish) shelf break. A distinct biogeochemical divide was observed, with Fe deficient surface waters present beyond the shelf break, much further eastwards than previously recognised. Due to along and on-shelf circulation, the Hebridean shelf represents a much-localised source of Fe, which does not fertilise the wider HLNA. Shelf sediments are generally thought to supply large quantities of Fe to overlying waters. However, for this Fe to influence upper-ocean biogeochemical cycling, efficient off-shelf transport mechanisms are required. This work challenges the view that the oceanic surface waters in close proximity to continental margins are iron replete with respect to marine primary production demands.
Attention to colors induces surround suppression at category boundaries
Authors: Fang Ming W. H. , Becker Mark W. , Liu Taosheng
Published: February 2019

We investigated how attention to a visual feature modulates representations of other features. The feature-similarity gain model predicts a graded modulation, whereas an alternative model asserts an inhibitory surround in feature space. Although evidence for both types of modulations can be found, a consensus has not emerged in the literature. Here, we aimed to reconcile these different views by systematically measuring how attention modulates color perception. Based on previous literature, we also predicted that color categories would impact attentional modulation. Our results showed that both surround suppression and feature-similarity gain modulate perception of colors but they operate on different similarity scales. Furthermore, the region of the suppressive surround coincided with the color category boundary, suggesting a categorical sharpening effect. We implemented a neural population coding model to explain the observed behavioral effects, which revealed a hitherto unknown connection between neural tuning shift and surround suppression.
Volcanic contribution to emergence of Central Panama in the Early Miocene
Authors: Buchs David M. , Irving Derek , Coombs Henry , Miranda Roberto , Wang Jian , Coronado Maurylis , Arrocha Rodrigo , Lacerda Mauricio , Goff Creed , Almengor Eladio , Portugal Enier , Franceschi Pastora , Chichaco Eric , Redwood Stewart D.
Published: February 2019

Formation of the Panama Isthmus, that had global oceanographic and biotic effects in the Neogene, is generally associated with tectonic uplift during collision of the Panama volcanic arc with South America. However, new field, geochemical and geochronological data from the Culebra Cut of the Panama Canal suggest that volcanism also contributed to the Isthmus emergence in the Early Miocene. This volcanism is recorded in a newly-recognised Central Panama volcanic field that includes several phases of development. Early activity of this field along the Panama Canal was associated with proximal effusive to explosive felsic products during formation of subaerial stratovolcanoes and possible domes ca. 21 Ma. This was followed by a period of marine transgression ca. 21–18 Ma, with more distal volcanism documented by tuffs that deposited in marine to terrestrial environments. Finally, proximal mafic volcanism formed tephra cones in a monogenetic field ca. 18(-?) Ma. This was associated with phreatomagmatic processes in a coastal environment, with remarkable kilometre-wide subvolcanic peperitic intrusions. We propose based on these observations that formation of the Central Panama volcanic field was critical in shaping regional topography, and that this could have actively contributed to obstruction and closure of an interoceanic strait in Central Panama.
NeuroD2 controls inhibitory circuit formation in the molecular layer of the cerebellum
Authors: Pieper Alexander , Rudolph Stephanie , Wieser Georg L. , Götze Tilmann , Mießner Hendrik , Yonemasu Tomoko , Yan Kuo , Tzvetanova Iva , Castillo Bettina Duverge , Bode Ulli , Bormuth Ingo , Wadiche Jacques I. , Schwab Markus H. , Goebbels Sandra
Published: February 2019

The cerebellar cortex is involved in the control of diverse motor and non-motor functions. Its principal circuit elements are the Purkinje cells that integrate incoming excitatory and local inhibitory inputs and provide the sole output of the cerebellar cortex. However, the transcriptional control of circuit assembly in the cerebellar cortex is not well understood. Here, we show that NeuroD2, a neuronal basic helix-loop-helix (bHLH) transcription factor, promotes the postnatal survival of both granule cells and molecular layer interneurons (basket and stellate cells). However, while NeuroD2 is not essential for the integration of surviving granule cells into the excitatory circuit, it is required for the terminal differentiation of basket cells. Axons of surviving NeuroD2-deficient basket cells follow irregular trajectories and their inhibitory terminals are virtually absent from Purkinje cells in Neurod2 mutants. As a result inhibitory, but not excitatory, input to Purkinje cells is strongly reduced in the absence of NeuroD2. Together, we conclude that NeuroD2 is necessary to instruct a terminal differentiation program in basket cells that regulates targeted axon growth and inhibitory synapse formation. An imbalance of excitation and inhibition in the cerebellar cortex affecting Purkinje cell output may underlay impaired adaptive motor learning observed in Neurod2 mutants.
CdSe/ZnS quantum dot encapsulated MoS2 phototransistor for enhanced radiation hardness
Authors: Park Jinwu , Yoo Geonwook , Heo Junseok
Published: February 2019

Notable progress achieved in studying MoS2 based phototransistors reveals the great potential to be applicable in various field of photodetectors, and to further expand it, a durability study of MoS2 phototransistors in harsh environments is highly required. Here, we investigate effects of gamma rays on the characteristics of MoS2 phototransistors and improve its radiation hardness by incorporating CdSe/ZnS quantum dots as an encapsulation layer. A 73.83% decrease in the photoresponsivity was observed after gamma ray irradiation of 400 Gy, and using a CYTOP and CdSe/ZnS quantum dot layer, the photoresponsivity was successfully retained at 75.16% on average after the gamma ray irradiation. Our results indicate that the CdSe/ZnS quantum dots having a high atomic number can be an effective encapsulation method to improve radiation hardness and thus to maintain the performance of the MoS2 phototransistor.
The role of Mannose Binding Lectin in the immune response against Borrelia burgdorferi sensu lato
Authors: Coumou Jeroen , Wagemakers Alex , Narasimhan Sukanya , Schuijt Tim J. , Ersoz Jasmin I. , Oei Anneke , de Boer Onno J. , Roelofs Joris J. T. H. , Fikrig Erol , Hovius Joppe W.
Published: February 2019

The causative agents of Lyme borreliosis, spirochetes belonging to the Borrelia burgdorferi sensu lato group, have developed several ways to protect themselves against killing by the host complement system. In addition, it has been shown that serum sensitive isolates are (partially) protected by the Ixodes Tick Salivary Lectin Pathway Inhibitor (TSLPI) protein; a salivary gland protein that inhibits the function of Mannose Binding Lectin (MBL). MBL is a C-type lectin that recognizes oligosaccharides on pathogens and activates the complement system via the lectin pathway. MBL deficiency has been linked to a more severe course of several infectious diseases and humans with detectable antibodies against B. burgdorferi are significantly more often MBL deficient compared to humans without antibodies against B. burgdorferi. Here we set out to investigate the role of MBL in the immune response against B. burgdorferi in more detail. We demonstrate that B. burgdorferi N40 needle-infected C57BL/6 MBL deficient mice harbored significantly higher B. burgdorferi numbers in skin tissue during the early course of infection. In line with these findings they also developed higher anti-B. burgdorferi IgG serum antibodies compared to WT controls. In contrast, B. burgdorferi loads in distant tissue such as heart, joints or bladder at later time points were similar for both mouse strains. These in vivo findings were corroborated using a B. burgdorferi N40-infected I. scapularis infestation model. We showed that MBL is capable of binding B. burgdorferi through its carbohydrate recognition domains, but in vitro complement killing assays, peritoneal macrophage and whole blood stimulations, phagocytosis assays and an in vivo migration experiment did not reveal the mechanism by which MBL facilitates early clearance of B. burgdorferi. To conclude, we show a protective role of MBL in the early stages of B. burgdorferi infection, yet the underlying mechanism warrants further investigation.
Nitrate and ammonium fluxes to diatoms and dinoflagellates at a single cell level in mixed field communities in the sea
Authors: Olofsson Malin , Robertson Elizabeth K. , Edler Lars , Arneborg Lars , Whitehouse Martin J. , Ploug Helle
Published: February 2019

Growth of large phytoplankton is considered to be diffusion limited at low nutrient concentrations, yet their constraints and contributions to carbon (C) and nitrogen fluxes in field plankton communities are poorly quantified under this condition. Using secondary ion mass spectrometry (SIMS), we quantified cell-specific assimilation rates of C, nitrate, and ammonium in summer communities of large phytoplankton when dissolved inorganic nitrogen concentrations are low in temperate coastal regions. Chain-forming diatoms composed 6% of total particulate organic carbon, but contributed 20% of C assimilation, 54% of nitrate assimilation and 32% of ammonium assimilation within the plankton community. In contrast, large dinoflagellates composed 11% of total POC, and contributed 14% of the C assimilation, 4% of ammonium and 9% of nitrate assimilation within the plankton community. Measured cell-specific C and nitrate assimilation rate match the Redfield ratio and the maximal nitrate assimilation in Chaetoceros spp. predicted by mass transfer theory. However, average ammonium assimilation rates were 30 and 340% higher than predicted by mass transfer theory in Tripos/Ceratium and Chaetoceros, respectively, suggesting that microbial interactions in the phycosphere may facilitate substantial luxury ammonium uptake by Chaetoceros in environments with fluctuating nitrate concentrations.
Microbes Producing L-Asparaginase free of Glutaminase and Urease isolated from Extreme Locations of Antarctic Soil and Moss
Authors: Ashok Anup , Doriya Kruthi , Rao Jyothi Vithal , Qureshi Asif , Tiwari Anoop Kumar , Kumar Devarai Santhosh
Published: February 2019

L-Asparaginase (L-asparagine aminohydrolase, E.C. 3.5.1.1) has been proven to be competent in treating Acute Lymphoblastic Leukaemia (ALL), which is widely observed in paediatric and adult groups. Currently, clinical L-Asparaginase formulations are derived from bacterial sources such as Escherichia coli and Erwinia chrysanthemi. These formulations when administered to ALL patients lead to several immunological and hypersensitive reactions. Hence, additional purification steps are required to remove toxicity induced by the amalgamation of other enzymes like glutaminase and urease. Production of L-Asparaginase that is free of glutaminase and urease is a major area of research. In this paper, we report the screening and isolation of fungal species collected from the soil and mosses in the Schirmacher Hills, Dronning Maud Land, Antarctica, that produce L-Asparaginase free of glutaminase and urease. A total of 55 isolates were obtained from 33 environmental samples that were tested by conventional plate techniques using Phenol red and Bromothymol blue as indicators. Among the isolated fungi, 30 isolates showed L-Asparaginase free of glutaminase and urease. The L-Asparaginase producing strain Trichosporon asahii IBBLA1, which showed the highest zone index, was then optimized with a Taguchi design. Optimum enzyme activity of 20.57 U mL−1 was obtained at a temperature of 30 °C and pH of 7.0 after 60 hours. Our work suggests that isolation of fungi from extreme environments such as Antarctica may lead to an important advancement in therapeutic applications with fewer side effects.
Elevated plasma D-dimer levels in dermatomyositis patients with cutaneous manifestations
Authors: Habe Koji , Wada Hideo , Higashiyama Ayaka , Akeda Tomoko , Tsuda Kenshiro , Mori Ryoko , Kakeda Masato , Yamanaka Keiichi , Mizutani Hitoshi
Published: February 2019

To explore the influence of dermatomyositis (DM)-specific cutaneous manifestations (scm) on systemic coagulation and fibrinolysis, we retrospectively studied plasma D-dimer levels with/without venous thromboembolism (VTE), malignancy, infection or other connective tissue diseases (CTDs) and scm. One hundred fifty patients with DM were retrospectively investigated using medical records regarding scm, VTE, malignancy, infection, other CTDs, laboratory data and systemic corticosteroid therapy. All DM patients were categorized as follows: group 1, without scm, VTE, infection, malignancy or other accompanying CTDs; group 2, with scm only; and group 3, with VTE, infection, malignancy and other accompanying CTDs but without scm. The D-dimer plasma levels were significantly increased in group 3 compared with healthy subjects and those in groups 1 and 2 (p < 0.001). The D-dimer plasma level in group 2 was significantly increased compared with healthy subjects and those in group 1 (p < 0.001). Increased D-dimer plasma levels were detected in DM patients with scm without detectable VTE, malignancy, infection or accompanying CTDs. In addition to the known risk factors for increased plasma D-dimer levels in DM patients, including VTE, malignancy, infection and other accompanying autoimmune diseases, the presence of cutaneous manifestations should be considered as a new clinical risk factor.
A Human iPSC-derived 3D platform using primary brain cancer cells to study drug development and personalized medicine
Authors: Plummer Simon , Wallace Stephanie , Ball Graeme , Lloyd Roslyn , Schiapparelli Paula , Quiñones-Hinojosa Alfredo , Hartung Thomas , Pamies David
Published: February 2019

A high throughput histology (microTMA) platform was applied for testing drugs against tumors in a novel 3D heterotypic glioblastoma brain sphere (gBS) model consisting of glioblastoma tumor cells, iPSC-derived neurons, glial cells and astrocytes grown in a spheroid. The differential responses of gBS tumors and normal neuronal cells to sustained treatments with anti-cancer drugs temozolomide (TMZ) and doxorubicin (DOX) were investigated. gBS were exposed to TMZ or DOX over a 7-day period. Untreated gBS tumors increased in size over a 4-week culture period, however, there was no increase in the number of normal neuronal cells. TMZ (100 uM) and DOX (0.3 uM) treatments caused ~30% (P~0.07) and ~80% (P < 0.001) decreases in the size of the tumors, respectively. Neither treatment altered the number of normal neuronal cells in the model. The anti-tumor effects of TMZ and DOX were mediated in part by selective induction of apoptosis. This platform provides a novel approach for screening new anti-glioblastoma agents and evaluating different treatment options for a given patient.
Impact of student-induced disturbance on stream macroinvertebrates differs among habitat types
Authors: Bossley Jon P. , Smiley Peter C.
Published: February 2019

Environmental impacts from ecotourism and outdoor recreation activities on terrestrial and aquatic ecosystems are well-reported in the literature, but less is known regarding the impacts of outdoor environmental education activities. Student activity during stream classes may cause substrate disruption and localized impacts on stream macroinvertebrates. We hypothesized that student activity would negatively impact macroinvertebrate community structure in three habitat types (riffle, run, pool) within a site regularly used for stream classes while no impact from student activity would occur in the same three habitat types within an unused site. We addressed the hypothesis by sampling macroinvertebrates monthly for one year in the riffles, runs, and pools at the class site and the unused site within a fourth order stream in central Ohio. The results indicated reduced macroinvertebrate abundance and richness in the riffle at the class site during periods with student activity and no differences between site types during periods without student activity. No impacts of stream classes on macroinvertebrate communities were observed in runs or pools. The results suggest that environmental education organizations should avoid repetitive use of the same site for their stream classes to avoid reductions of macroinvertebrate abundance and taxa richness that can impact the students’ educational experience.
Performance of Cystatin C-Based Equations for Estimation of Glomerular Filtration Rate in Diabetes Patients: A Prisma-Compliant Systematic Review and Meta-Analysis
Authors: Cheuiche Amanda Veiga , Queiroz Marina , Azeredo-da-Silva André Luis Ferreira , Silveiro Sandra Pinho
Published: February 2019

The accuracy of estimated glomerular filtration rate (eGFR) equations in diabetes mellitus (DM) patients has been extensively questioned. We evaluated the performance of cystatin C-based equations alone or in combination with creatinine to estimate GFR in DM patients. A PRISMA-compliant systematic review was performed in the MEDLINE and Embase databases, with “diabetes mellitus” and “cystatin C” as search terms. Studies comparing cystatin C-based eGFR equations with measured GFR (mGFR) in DM patients were eligible. Accuracies P10, P15, P20, and P30 indicated the proportion of eGFR results within 10, 15, 20, and 30% of mGFR. Single-arm meta-analyses were conducted, and the Quality of Diagnostic Accuracy Studies-II tool (QUADAS-2) was applied. Twenty-three studies comprising 7065 participants were included, and 24 equations were analyzed in a broad range of GFRs. Meta-analyses were completed for 10 equations. The mean P30 accuracies of the equations ranged from 41% to 87%, with the highest values found with both CKD-EPI equations. Mean P10-P15 achieved 35% in the best scenario. A sensitivity analysis to evaluate different mGFR methods did not change results. In conclusion, cystatin C-based eGFR equations represent measured GFR fairly at best in DM patients, with high variability among the several proposed equations.