bluuebunny/crossref_metadata_2025 huggingface dataset:
“Treasure maps” for magnetic high-entropy-alloys from theory and experiment
Authors: Körmann F. , Ma D. , Belyea D. D. , Lucas M. S. , Miller C. W. , Grabowski B. , Sluiter M. H. F.
Published: October 2015

The critical temperature and saturation magnetization for four- and five-component FCC transition metal alloys are predicted using a formalism that combines density functional theory and a magnetic mean-field model. Our theoretical results are in excellent agreement with experimental data presented in both this work and in the literature. The generality and power of this approach allow us to computationally design alloys with well-defined magnetic properties. Among other alloys, the method is applied to CoCrFeNiPd alloys, which have attracted attention recently for potential magnetic applications. The computational framework is able to predict the experimentally measured TC and to explore the dominant mechanisms for alloying trends with Pd. A wide range of ferromagnetic properties and Curie temperatures near room temperature in hitherto unexplored alloys is predicted in which Pd is replaced in varying degrees by, e.g., Ag, Au, and Cu.
Tailoring diffuse reflectance of inhomogeneous films containing microplatelets
Authors: Slovick Brian A. , Baker John M. , Flom Zachary , Krishnamurthy Srini
Published: October 2015

We develop an analytical model for calculating the diffuse reflectance of inhomogeneous films containing aligned microplatelets with diameters much greater than the wavelength. The scattering parameters are derived by modeling the platelets as one-dimensional thin films, and the overall diffuse reflectance of the slab is calculated using the Kubelka-Munk model. Our model predicts that reflection minima and maxima arising from coherent interference within the platelets are preserved in the diffuse reflectance of the disordered slab. Experimental validation of the model is provided by reflectance measurements (0.3–15 μm) of a solid aerosol film of aligned hexagonal boron nitride platelets.
Electronic band structure of highly mismatched GaN1−xSbx alloys in a broad composition range
Authors: Segercrantz N. , Yu K. M. , Ting M. , Sarney W. L. , Svensson S. P. , Novikov S. V. , Foxon C. T. , Walukiewicz W.
Published: October 2015

In this letter, we study the optical properties of GaN1−xSbx thin films. Films with an Sb fraction up to 42% were synthesized by alternating GaN-GaSb layers at a constant temperature of 325 °C. The measured optical absorption data of the films are interpreted using a modified band anticrossing model that is applicable to highly mismatched alloys such as GaN1−xSbx in the entire composition range. The presented model allows us to more accurately determine the band gap as well as the band edges over the entire composition range thereby providing means for determining the composition for, e.g., efficient spontaneous photoelectrochemical cell applications.
Particle-in-cell based parameter study of 12-cavity, 12-cathode rising-sun relativistic magnetrons for improved performance
Authors: Majzoobi A. , Joshi R. P. , Neuber A. A. , Dickens J. C.
Published: October 2015

Particle-in-cell simulations are performed to analyze the efficiency, output power and leakage currents in a 12-Cavity, 12-Cathode rising-sun magnetron with diffraction output (MDO). The central goal is to conduct a parameter study of a rising-sun magnetron that comprehensively incorporates performance enhancing features such as transparent cathodes, axial extraction, the use of endcaps, and cathode extensions. Our optimum results demonstrate peak output power of about 2.1 GW, with efficiencies of ∼70% and low leakage currents at a magnetic field of 0.45 Tesla, a 400 kV bias with a single endcap, for a range of cathode extensions between 3 and 6 centimeters.
Creating periodic local strain in monolayer graphene with nanopillars patterned by self-assembled block copolymer
Authors: Mi Hongyi , Mikael Solomon , Liu Chi-Chun , Seo Jung-Hun , Gui Gui , Ma Alice L. , Nealey Paul F. , Ma Zhenqiang
Published: October 2015

A simple and viable method was developed to produce biaxial strain in monolayer graphene on an array of SiO2 nanopillars. The array of SiO2 nanopillars (1 cm2 in area, 80 nm in height, and 40 nm in pitch) was fabricated by employing self-assembled block copolymer through simple dry etching and deposition processes. According to high resolution micro-Raman spectroscopy and atomic force microscopy analyses, 0.9% of maximum biaxial tensile strain and 0.17% of averaged biaxial tensile strain in graphene were created. This technique provides a simple and viable method to form biaxial tensile strain in graphene and offers a practical platform for future studies in graphene strain engineering.
High cooperativity coupling between a phosphorus donor spin ensemble and a superconducting microwave resonator
Authors: Zollitsch Christoph W. , Mueller Kai , Franke David P. , Goennenwein Sebastian T. B. , Brandt Martin S. , Gross Rudolf , Huebl Hans
Published: October 2015

We investigate the coupling of an ensemble of phosphorus donors in an isotopically purified 28Si host lattice interacting with a superconducting coplanar waveguide resonator. The microwave transmission spectrum of the resonator shows a normal mode splitting characteristic for high cooperativity. The evaluated collective coupling strength geff is of the same order as the loss rate of the spin system γ, indicating the onset of strong coupling. We develop a statistical model to describe the influence of temperature on the coupling strength from 50 mK to 3.5 K and find a scaling of the coupling strength with the square root of the number of thermally polarized spins.
Ab-initio study of dynamical properties of two dimensional MoS2 under strain
Authors: Soni Himadri , Jha Prafulla K.
Published: October 2015

In this paper, we report the biaxial strain induced modifications in the phonon dispersion curves of monolayer MoS2 using first principles calculations in the framework of density functional perturbation theory. We have used the ultrasoft psedopotentials and the exchange correlation energies have been approximated by the local density approximation. There are significant changes in the phonon dispersion curves under strain. A systematic decrease in the optical phonon modes is observed with strain percentage. The longitudinal and transverse acoustic phonon modes of monolayer MoS2 show linear dependency for both without and with strain cases. However, the out of plane acoustic mode (ZA) which behaves quadratically with wave vector k- turns linear under strain. We have also linked ripple in single layer (SL) MoS2 by ZA mode with strain using shell elasticity theory. The strain induced softening of linear behaviour of ZA mode with strain indicates the absence of rippling under strain. At a very high strain there is a possibility of structural phase transition as the ZA mode at zone centre turns imaginary above 15% strain. Our results indicate a close relationship between the morphology and properties enabling the device tailoring and bandgap engineering in SL-MoS2 by manipulating the strain.
Characterisation of bioaccumulation dynamics of three differently coated silver nanoparticles and aqueous silver in a simple freshwater food chain
Authors: Kalman Judit , Paul Kai B. , Khan Farhan R. , Stone Vicki , Fernandes Teresa F.
Published: October 2015

Environmental context Nanoparticles may be passed from primary producers to predators higher up the food chain, but little is currently known about this transfer. We studied the accumulation dynamics of silver nanoparticles by algae, and then from algae to zooplankton. Using the biodynamic approach, we reconstructed the accumulation process to show that diet is the primary route of uptake for silver nanoparticles. Abstract This study investigated the bioaccumulation dynamics of silver nanoparticles (Ag NPs) with different coatings (polyvinyl pyrrolidone, polyethylene glycol and citrate), in comparison with aqueous Ag (added as AgNO3), in a simplified freshwater food chain comprising the green alga Chlorella vulgaris and the crustacean Daphnia magna. Algal uptake rate constants (ku) and membrane transport characteristics (binding site density, transporter affinity and strength of binding) were determined after exposing algae to a range of either aqueous Ag or Ag NP concentrations. In general, higher ku values were related to higher toxicity in the algae. Transmission electron microscopy images were used to investigate the internalisation of Ag NPs in algal cells following exposure to low concentrations for 72h (mimicking inhibition tests) or high concentrations for 4h (mimicking preparation for daphnia dietary exposure). Ag NPs were only visualised in algal cells exposed to high Ag NP concentrations. To establish D. magna biodynamic model constants, organisms were fed Ag-contaminated algae and depurated for 96h. Assimilation efficiencies ranged from 10 to 25% and the elimination of accumulated Ag followed a two-compartmental model, indicating lower loss rate constants for polyvinyl pyrrolidone-, and polyethylene glycol-coated Ag NPs. Biodynamic model results revealed that in most cases, food is the dominant pathway of Ag uptake in D. magna. Despite the predicted low steady-state body burdens in D. magna, dietary uptake of Ag was possible from aqueous and particulate forms of Ag.
Developing a sentinel mollusc species for toxicity assessment: metal exposure, dose and response – laboratory v. field exposures and resident organisms
Authors: Taylor Anne , Maher William
Published: October 2015

Environmental contextMetal contamination in estuarine sediments can affect ecosystem health. Molluscs are commonly used as environmental indicators because they accumulate contaminants that cause adverse health effects. We investigated metal uptake and effects in the Sydney cockle, comparing exposure to contaminated lake sediments in situ and in laboratory aquariums. Although differences were observed between the different exposure types, all approaches were found to be valid for investigating metal health effects in this organism.
AbstractRelationships between exposure, tissue dose and biological responses of the benthic marine bivalve Anadara trapezia to an estuarine sediment zinc, copper, lead, cadmium and selenium contamination gradient in Lake Macquarie, NSW, were evaluated using three approaches. Organisms were exposed to sediments in laboratory aquaria, caged in situ in the lake and lake resident organisms collected. Dose included total metal tissue burden and subcellular metal distribution to determine metabolically available metal. Response indices were total antioxidant capacity, lipid peroxidation, lysosomal stability and condition index. Bioaccumulation of total metals was higher in the laboratory and resident organisms than in those transplanted in the field but the contribution of individual metals to the total differed. Laboratory-exposed organisms had increased concentrations of cadmium and lead in their biologically active and detoxified metal fractions but not of the essential elements zinc and copper. Subcellular metal distribution patterns were the same in resident organisms but cadmium and lead burdens were higher in both fractions. Biomarker responses were similar in laboratory, transplanted and resident organisms. Total antioxidant capacity was significantly reduced and lipid peroxidation and lysosomal destabilisation significantly increased in all metal-exposed organisms compared with the reference A. trapezia. Condition index of laboratory-exposed organisms was significantly lower than in situ, resident and reference organisms. Clear metal exposure–dose–response relationships have been demonstrated for A. trapezia in laboratory and in situ experiments. Non-resident organisms, in both exposure scenarios, gave similar responses to resident metal-exposed organisms, showing all approaches are valid when investigating effects in this species.
Competition indices of three perennial grasses used to rehabilitate degraded semi-arid rangelands in Kenya
Authors: Mganga K. Z. , Musimba N. K. R. , Nyariki D. M.
Published: October 2015

Rangeland degradation is one of the most serious environmental challenges in arid and semi-arid environments in Africa. Grass reseeding technology, using indigenous perennial grass species has a great potential for restoring ecosystem functionality in these degraded lands. This study was aimed at investigating how the establishment of indigenous grasses used to rehabilitate degraded semi-arid rangelands in Kenya as monocultures or binary mixtures affect dry matter biomass yields and plant competition indices at different phenological stages of development: seedling, elongation and reproduction. Using plant competition indices, we demonstrated which among these grass species showed a complementary vis-à-vis competitive interaction in binary mixtures across their phenological stages. Monocultures and binary mixtures of three perennial grass species: Cenchrus ciliaris L. (Buffel grass), Enteropogon macrostachyus Munro ex Benth. (Bush ryegrass) and Eragrostis superba Peyr. (Wilman lovegrass) native to these semi-arid rangelands were established in a field experiment. Pure stands of E. macrostachyus yielded higher biomass than C. ciliaris and E. superba only at the seedling and elongation phases but not the reproduction phase, where the yields were lowest among pure stands. Negative plant interactions in binary mixtures were observed at seedling and reproduction stages, compared with positive interactions observed at the elongation phase. Binary grass mixtures had a significant advantage for exploiting available environmental resources only at the elongation phase but not at the seedling and reproduction phases. Based on the estimated competition indices, E. superba best complements C. ciliaris across the phenological stages. We therefore conclude that this binary mixture is the one most likely to ensure successful rehabilitation of degraded semi-arid rangelands in this region.
Melanopsin-driven increases in maintained activity enhance thalamic visual response reliability across a simulated dawn
Authors: Storchi Riccardo , Milosavljevic Nina , Eleftheriou Cyril G. , Martial Franck P. , Orlowska-Feuer Patrycja , Bedford Robert A. , Brown Timothy M. , Montemurro Marcelo A. , Petersen Rasmus S. , Lucas Robert J.
Published: October 2015

Significance

Irradiance-dependent (“luxotonic”) changes in baseline firing were first described in neurones of the early visual system decades ago. However, the origin and function (if any) of this visual response is still poorly understood. Here we address both questions by recording electrophysiological activity in mouse dorsal lateral geniculate nucleus over a simulated dawn. First, we show that in the photopic regime luxotonic activity becomes increasingly driven by inner-retinal melanopsin photoreceptors as irradiance increases. Then, that irradiance-dependent increases in activity apply not only to baseline firing but also to the amplitude of fast visual responses, producing increases in signal:noise across the simulated dawn, revealing a function for luxotonic activity and a new way in which inner retinal photoreceptors support conventional vision.
Contribution of cyanobacterial alkane production to the ocean hydrocarbon cycle
Authors: Lea-Smith David J. , Biller Steven J. , Davey Matthew P. , Cotton Charles A. R. , Perez Sepulveda Blanca M. , Turchyn Alexandra V. , Scanlan David J. , Smith Alison G. , Chisholm Sallie W. , Howe Christopher J.
Published: October 2015

Significance

A number of organisms synthesize hydrocarbons, but the scale at which this occurs in the environment is unknown. Here, we provide the first global estimates of hydrocarbon production by the two most abundant cyanobacteria on Earth,
Prochlorococcus
and
Synechococcus
. We suggest that these organisms represent a significant and widespread source of hydrocarbons to the world’s oceans, which in turn may sustain populations of obligate hydrocarbon-degrading bacteria known to be important in consuming anthropogenic oil spills. Our study demonstrates the role cyanobacteria play in the ocean ‟hydrocarbon cycle” and reveals the massive scale of this process. The widespread distribution of cyanobacteria and hydrocarbon-degrading bacteria in freshwater, marine, and terrestrial environments suggests the hydrocarbon cycle is pervasive in many natural ecosystems.
Rapid Y degeneration and dosage compensation in plant sex chromosomes
Authors: Papadopulos Alexander S. T. , Chester Michael , Ridout Kate , Filatov Dmitry A.
Published: October 2015

Significance

Sex chromosomes have repeatedly evolved in animals and plants, but the evolutionary forces driving this process are not entirely understood. Nonrecombining Y chromosomes undergo rapid loss of functional genes in animals; however, it remains unclear whether this holds true in plants. We report the first genome sequence-based analysis of sex chromosomes in white campion, to our knowledge, which evolved large sex chromosomes only 10 million years ago. We demonstrate that the Y chromosome has lost nearly half its functional genes, at a rate of Y degeneration comparable to that of animal Y chromosomes. This degeneration is accommodated for by highly variable dosage compensation. Our results resolve the puzzling discrepancy in evolutionary trajectories of sex chromosomes between the plant and animal kingdoms.
Mechanism for rapid passive-dynamic prey capture in a pitcher plant
Authors: Bauer Ulrike , Paulin Marion , Robert Daniel , Sutton Gregory P.
Published: October 2015

Significance

Carnivorous pitcher plants have thus far been considered a classic example of passive, motionless pitfall traps. Here, we describe a rapid, passive-dynamic movement used by an AsianNepenthespitcher plant to capture insect prey. We show that the pitcher lid functions as a rain-driven torsion spring that combines material properties adapted for momentum transfer with a unique friction-reducing surface coating. Unlike other pitcher traps, this capture mechanism employs rapid movement. It also differs from the metabolically costly mechanisms of active carnivorous plants such as Venus flytraps because the movement is externally driven. It therefore establishes a new category of rapid plant movements that challenges the conventional distinction between active and passive carnivorous plant traps.
Expected time-invariant effects of biological traits on mammal species duration
Authors: Smits Peter D.
Published: October 2015

Significance

Determining which biological traits influence differences in extinction risk is vital for understanding differential diversification of life and for making predictions about species’ vulnerability to human impacts. The durations of fossil species are a rich source of information for estimating systematic differences in extinction risk. I analyzed Cenozoic North American fossil mammal species durations and their relationship with multiple ecological traits, their time of origination, and their shared evolutionary histories. I find support for generalists having a lower extinction risk than specialists as a general statement. When these results are compared with risk factors associated with living mammals, I find some incongruities that may indicate that the current biodiversity crisis is akin to the great mass extinctions in Earth’s history.
Disulphide-reduced psoriasin is a human apoptosis-inducing broad-spectrum fungicide
Authors: Hein Kyaw Zaw , Takahashi Hitoshi , Tsumori Toshiko , Yasui Yukihiko , Nanjoh Yasuko , Toga Tetsuo , Wu Zhihong , Grötzinger Joachim , Jung Sascha , Wehkamp Jan , Schroeder Bjoern O. , Schroeder Jens M. , Morita Eishin
Published: October 2015

Significance

Fungi increasingly cause serious medical problems in immunocompromised populations. Antimicrobial peptides are primary effector molecules of innate immune systems. Antimicrobial peptides successfully protect healthy humans from bacterial infections. However, it is largely unknown how and why human body surfaces resist fungal infections. We identified the common epithelial protein, psoriasin (S100A7), in its disulphide-reduced form (redS100A7) as the principal antifungal factor of human body surfaces. redS100A7 kills several pathogenic fungi using a mechanism that differs from conventional antifungal agents. Thus, this study might contribute to a better understanding of human defense systems against fungal infection and the development of urgently needed novel antifungal therapeutics.
Coexistence of both gyroid chiralities in individual butterfly wing scales of
Callophrys rubi
Authors: Winter Benjamin , Butz Benjamin , Dieker Christel , Schröder-Turk Gerd E. , Mecke Klaus , Spiecker Erdmann
Published: October 2015

Significance

Arthropod biophotonic nanostructures provide a plethora of complex geometries. Although the variety of geometric forms observed reflects those found in amphiphilic self-assembly, the biological formation principles are more complex. This paper addresses the chiral single gyroid in the Green Hairstreak butterfly
Callophrys rubi
, robustly showing that the formation process produces both the left- and right-handed enantiomers but with distinctly different likelihood. An interpretation excludes the molecular chirality of chitin as the determining feature of the enantiomeric type, emphasizing the need to identify other chirality-specific factors within the membrane-based biological formation model. These findings contribute to an understanding of nature’s ability to control secondary features of the structure formation, such as enantiomeric type and crystallographic texture, informing bioinspired self-assembly strategies.
Resistance to ketolide antibiotics by coordinated expression of rRNA methyltransferases in a bacterial producer of natural ketolides
Authors: Almutairi Mashal M. , Park Sung Ryeol , Rose Simon , Hansen Douglas A. , Vázquez-Laslop Nora , Douthwaite Stephen , Sherman David H. , Mankin Alexander S.
Published: October 2015

Significance

Studies of antibiotic resistance are usually initiated in earnest only after resistance has become established in clinical pathogens. Here, we forewarn of a resistance mechanism to the novel antibiotics ketolides, which are only coming into broad medical practice. We show that the balanced activities and coordinated expression of two genes,
pikR1
and
pikR2
, provide efficient protection to
Streptomyces venezuelae
, a bacterial producer of natural ketolides. Expression of the more potent gene,
pikR2
, is supported by
pikR1
and specifically induced by ketolides. The resistance mechanism remains fully functional when
pikR1
and
pikR2
are transferred to other bacterial species and affords protection against clinical ketolides. These findings emphasize the need for the preemptive development of antibiotics that can overcome this resistance mechanism.
Kin discrimination between sympatric
Bacillus subtilis
isolates
Authors: Stefanic Polonca , Kraigher Barbara , Lyons Nicholas Anthony , Kolter Roberto , Mandic-Mulec Ines
Published: October 2015

Significance

Microorganisms are directly influenced by actions of their neighbors, and cooperative behaviors are favored among relatives. Only a few microbial species are known to discriminate between kin and nonkin, and distribution of this trait within sympatric bacterial populations is still poorly understood. Here we provide evidence of kin discrimination among micrometer-scale soil isolates of
Bacillus subtilis
, which is reflected in striking boundaries between nonkin sympatric conspecifics during cooperative swarming on agar. Swarming incompatibilities were frequent and correlated with phylogenetic relatedness, as only the most related strains merged swarms. Moreover, mixing of strains during colonization of a plant root suggested possible antagonism between nonkin. The work sheds light on kin discrimination on a model Gram-plus bacterium.
Remodeling nuclear architecture allows efficient transport of herpesvirus capsids by diffusion
Authors: Bosse Jens B. , Hogue Ian B. , Feric Marina , Thiberge Stephan Y. , Sodeik Beate , Brangwynne Clifford P. , Enquist Lynn W.
Published: October 2015

Significance

The nucleus is structured into chromatin and interchromatin compartments. Its sieve-like architecture permits individual proteins to rapidly diffuse while large macromolecular assemblies are corralled in the interchromatin. Herpesvirus capsids assemble in the nucleus and have to access the nuclear periphery for exit. It was hypothesized that nuclear herpesvirus capsids recruit filamentous actin and molecular motor protein to overcome nuclear entrapment. Here we use “ring-sheet” microscopy to track nuclear capsids with high spatiotemporal resolution. We report that nuclear herpesvirus capsids do not use directed motility. Instead, virus infection changes nuclear architecture, which allows capsids to reach the nuclear membranes by diffusion. Our findings illustrate a pathway for very large macromolecular assemblies to cross the nucleoplasm without directed motility.
Algal ancestor of land plants was preadapted for symbiosis
Authors: Delaux Pierre-Marc , Radhakrishnan Guru V. , Jayaraman Dhileepkumar , Cheema Jitender , Malbreil Mathilde , Volkening Jeremy D. , Sekimoto Hiroyuki , Nishiyama Tomoaki , Melkonian Michael , Pokorny Lisa , Rothfels Carl J. , Sederoff Heike Winter , Stevenson Dennis W. , Surek Barbara , Zhang Yong , Sussman Michael R. , Dunand Christophe , Morris Richard J. , Roux Christophe , Wong Gane Ka-Shu , Oldroyd Giles E. D. , Ané Jean-Michel
Published: October 2015

Significance

Colonization of land by plants was a critical event for the emergence of extant ecosystems. The innovations that allowed the algal ancestor of land plants to succeed in such a transition remain unknown. Beneficial interaction with symbiotic fungi has been proposed as one of these innovations. Here we show that the genes required for this interaction appeared in a stepwise manner: Some evolved before the colonization of land by plants and others first appeared in land plants. We thus propose that the algal ancestor of land plants was preadapted for interaction with beneficial fungi and employed these gene networks to colonize land successfully.
Targeting glutamine metabolism rescues mice from late-stage cerebral malaria
Authors: Gordon Emile B. , Hart Geoffrey T. , Tran Tuan M. , Waisberg Michael , Akkaya Munir , Kim Ann S. , Hamilton Sara E. , Pena Mirna , Yazew Takele , Qi Chen-Feng , Lee Chen-Fang , Lo Ying-Chun , Miller Louis H. , Powell Jonathan D. , Pierce Susan K.
Published: October 2015

Significance

Cerebral malaria (CM) is a deadly complication of
Plasmodium falciparum
infection in African children despite effective antimalarial treatment. Once signs of neurologic disease have commenced, there is no adjunctive treatment for CM, and overall mortality remains high. Thus, a treatment that arrests disease and promotes healing in the late stages is urgently needed. Here we report, in an animal model of CM, that the glutamine analog 6-diazo-5-oxo-L-norleucine (DON) is an effective therapy even when treatment is initiated after infected animals show neurological signs of disease. Within hours of DON treatment blood–brain barrier integrity was restored, and brain swelling was reduced. These results suggest DON as a strong candidate for an effective adjunctive therapy for CM in African children.
Elevation of 20-carbon long chain bases due to a mutation in serine palmitoyltransferase small subunit b results in neurodegeneration
Authors: Zhao Lihong , Spassieva Stefka , Gable Kenneth , Gupta Sita D. , Shi Lan-Ying , Wang Jieping , Bielawski Jacek , Hicks Wanda L. , Krebs Mark P. , Naggert Juergen , Hannun Yusuf A. , Dunn Teresa M. , Nishina Patsy M.
Published: October 2015

Significance

Sphingolipids are essential in eukaryotes and are particularly important in neural tissues. Generally, sphingolipids have an 18-carbon (C18) long chain base (LCB) backbone. However, low-abundance sphingolipids containing LCBs of 16 or 20 carbons have also been discovered. Yet their specific functions and biological significance is not known. This work demonstrates that elevation of 20-carbon LCBs and/or sphingolipids containing C20 LCBs has detrimental neurodegenerative effects in the brain and the retina, leading to perturbation of protein homeostasis. This work describes, for the first time to our knowledge, the specific pathological roles of a class of low-abundance LCBs in vivo.
Power decreases trust in social exchange
Authors: Schilke Oliver , Reimann Martin , Cook Karen S.
Published: October 2015

Significance

Trust is pivotal to the functioning of society. This work tests competing predictions about how having low vs. high power may impact people’s tendency to place trust in others. Using different experimental paradigms and measures and confirming predictions based on motivated cognition theory, we show that people low in power are significantly more trusting than more powerful people and that this effect can be explained by the constructs of hope and perceived benevolence. Our findings make important contributions to the literatures on trust, power, and motivated cognition.
cKit
+
cardiac progenitors of neural crest origin
Authors: Hatzistergos Konstantinos E. , Takeuchi Lauro M. , Saur Dieter , Seidler Barbara , Dymecki Susan M. , Mai Jia Jia , White Ian A. , Balkan Wayne , Kanashiro-Takeuchi Rosemeire M. , Schally Andrew V. , Hare Joshua M.
Published: October 2015

Significance

A high-resolution genetic lineage-tracing study in mice reveals that cKit identifies multipotent progenitors of cardiac neural crest (CNC) origin. Normally, the proportion of cardiomyocytes produced from this lineage is limited, not because of poor differentiation capacity as previously thought, but because of stage-specific changes in the activity of the bone morphogenetic protein pathway. Transient bone morphogenetic protein antagonism efficiently directs mouse iPSCs toward the CNC lineage and, consequently, the generation of cKit
+
CNCs with full capacity to form cardiomyocytes and other CNC derivatives in vitro. These findings resolve a long-standing controversy regarding the role of cKit in the heart, and are expected to lead to the development of novel stem cell-based therapies for the prevention and treatment of cardiovascular disease.
Relation between rainfall intensity and savanna tree abundance explained by water use strategies
Authors: Xu Xiangtao , Medvigy David , Rodriguez-Iturbe Ignacio
Published: October 2015

Significance

Savannas account for 20% of global land area and support 30% of terrestrial net primary production. The biome is characterized by the coexistence of trees and grasses. Tree abundance strongly influences savanna ecosystem dynamics. Maximum tree abundance in tropical savannas is found to be negatively correlated with rainfall intensity, which remains unexplained. Through combining in situ observations, a biophysical tree–grass competition model, and a stochastic rainfall generator, we present that differentiated tree and grass water use strategies are essential to explain the phenomenon. Our findings show the importance of vegetation physiology in determining tree abundance in the biome and enhance our ability to predict future ecosystem composition and dynamics under global change.
Effects of Turbidity on Prey Selection and Foraging Return of Adult Largemouth Bass in Reservoirs
Authors: Shoup Daniel E. , Drew Lane W.
Published: October 2015

Previous laboratory studies have demonstrated that turbidity alters prey selection by Largemouth Bass Micropterus salmoides, but this has not been tested in the field. Laboratory studies have also suggested that daily rates of consumption by Largemouth Bass may decline as turbidity increases and that the rate of decline may differ among prey types, possibly providing a mechanism that drives the observed prey selection patterns. We conducted laboratory trials to measure daily consumption rates for Largemouth Bass when foraging on Bluegills Lepomis macrochirus and Gizzard Shad Dorosoma cepedianum; we also collected field data in three reservoir systems (Boomer, Sooner, and Guthrie lakes, Oklahoma) during 2 years to evaluate Largemouth Bass prey selection and consumption rates over a range of turbidity levels. In the laboratory trials, Largemouth Bass daily consumption rates declined with increased turbidity, but the decline was similar between the two prey types. We detected no correlations between turbidity and consumption rate (percentage of empty stomachs or mean weight of prey in stomach contents) in the field. Field-measured prey selection was highly variable among reservoirs and between sampling years, yet all but one reservoir ×× year combination had significant correlations between prey selection and turbidity, which generally followed the predictions of previous laboratory results (greater use of fish prey [especially centrarchids] and reduced use of crayfish at high levels of turbidity). However, the use of crayfish prey under low-turbidity conditions was higher than that expected based on previous laboratory trials. Further research is needed to determine which factors regulate the effects of increased turbidity on predator foraging return and to evaluate the food web implications of turbidity-related changes in the diets of top predators.

Received December 3, 2014; accepted June 25, 2015
No evidence of risk-taking or impulsive behaviour in a person with episodic amnesia: Implications for the role of the hippocampus in future-regarding decision-making
Authors: Rosenbaum R. S. , Kwan D. , Floden D. , Levine B. , Stuss D. T. , Craver C. F.
Published: October 2015

Does advantageous decision-making require one to explicitly remember the outcome of a series of past decisions or to imagine future personal consequences of one's choices? Findings that amnesic people with hippocampal damage cannot form a clear preference for advantageous decks over many learning trials on the Iowa Gambling Task (IGT) have been taken to suggest that complex decision-making on the IGT depends on declarative (episodic) memory and hippocampal integrity. Alternatively, impaired IGT performance in amnesic individuals could be secondary to risk-taking and/or impulsive behaviour resulting from impaired episodic future thinking (i.e. prospection) known to accompany amnesia. We tested this possibility in the amnesic individual K.C. using the IGT and the Toronto Gambling Task (TGT), a novel task that dissociates impulsivity from risk-taking without placing demands on declarative memory. K.C. did not develop a preference for advantageous over disadvantageous decks on the IGT and, instead, showed a slight preference for short-term gains and an inability to acquire a more adaptive appreciation of longer-term losses. He also did not display impulsive or risk-taking behaviour on the TGT, despite a profound inability to imagine personal future experiences. These findings suggest that impaired decision-making on the IGT in amnesia is unlikely to reflect a predilection to act in the moment or failure to take future consequences into account. Instead, some forms of future-regarding decision-making may be dissociable, with performance on tasks relying on declarative learning or on episodic-constructive processes more likely to be impaired.
Constraints on the distribution of supernova remnants with Galactocentric radius
Authors: Green D A
Published: October 2015

Supernova remnants (SNRs) in the Galaxy are an important source of energy injection into the interstellar medium, and also of cosmic rays. Currently there are 294 known SNRs in the Galaxy, and their distribution with Galactocentric radius is of interest for various studies. Here I discuss some of the statistics of Galactic SNRs, including the observational selection effects that apply, and difficulties in obtaining distances for individual remnants from the ‘$\Sigma$–D’ relation. Comparison of the observed Galactic longitude distribution of a sample of bright Galactic SNRs – which are not strongly affected by selection effects – with those expected from models is used to constrain the Galactic distribution of SNRs. The best-fitting power-law/exponential model is more concentrated towards the Galactic Centre than the widely used distribution obtained by Case & Bhattacharya.
Rheological Studies on the Reaction of Zein with Polyethylenemaleic Anhydride
Authors: Selling Gordon W. , Byars Jeffrey A. , Utt Kelly D.
Published: October 2015

There continues to be interest in developing solvent‐resistant articles from biobased renewable materials to successfully compete with petrochemical products. It was previously shown that reaction of zein with polyethylenemaleic anhydride (PEMA) provides articles that are solvent resistant. The gelation kinetics for the reaction of PEMA with zein was investigated rheologically to better understand this chemistry. The reaction of the nucleophilic groups on zein with the anhydrides on PEMA is the main cause for the gelation reaction. The gelation time was defined as being the point when the elastic modulus (G′) and viscous modulus (G″) cross. In this work, the rate of reaction, in terms of time to gelation, was studied in N,N‐dimethylformamide solution for which the amount of PEMA, the reaction temperature, and the overall reaction concentration were varied. Exponential relationships were found between the gelation time and % PEMA, temperature, and % solids, as well as between elastic modulus with either % PEMA or % solids. The concentration of PEMA had the largest impact on gelation time, for which going from 2.5% PEMA to 6% PEMA reduced the gelation time from 63,114 to 1,576 s. The temperature dependence of this gelation reaction was well described by an Arrhenius plot with an apparent activation energy of 50.5 kJ/mol.
Risks of Being Malignant or High Risk and Their Characteristics in Breast Lesions 20 mm or Larger After Benign Results on Ultrasonography-Guided 14-Gauge Core Needle Biopsy
Authors: Moon Hee Jung , Kim Min Jung , Yoon Jung Hyun , Kim Eun-Kyung
Published: October 2015

Purpose

The malignancy risk, risk of being high-risk lesions after benign results on ultrasonography-guided 14-gauge core needle biopsies (US-CNBs), and their characteristics in breast lesions of 20 mm or greater were investigated.

Methods

Eight hundred forty-seven breast lesions with benign results on US-CNB were classified as benign, high risk, and malignant through excision and clinical follow-up. The risks of being malignant or high risk were analyzed in all lesions, lesions 20 to 29 mm, and lesions 30 mm or greater. Their clinicopathological characteristics were evaluated.

Results

Of 847, 18 (2.1%) were malignant, 53 (6.3%) were high-risk lesions, and 776 (91.6%) were benign. Of 18 malignancies, 6 (33.3%) were malignant phyllodes tumors and 12 (66.7%) were carcinomas. In benign lesions 20 to 29 mm, risks of being malignant or high risk were 1.6% (9 of 566) and 4.4% (25 of 566). In 281 lesions 30 mm or greater, the risks of being malignant or high risk were 3.2% and 10%. The risk of being high risk in lesions 30 mm or greater was 10%, significantly higher than 4.4% of lesions 20 to 29 mm (P = 0.002).

Conclusions

Excision can be considered in lesions measuring 20 mm or larger because of the 2.1% malignancy risk and the 6.3% risk of being high-risk lesions despite benign results on US-CNB. Excision should be considered in lesions measuring 30 mm or larger because of the 3.2% malignancy risk and the 10% risk of being high-risk lesions.
Thyroid Nodule Doubling Time is Not a Reliable Indicator of Benign or Malignant Nature
Authors: Clark Toshimasa J.T. , Pokharel Sajal , Meier Jeffrey , Wang Carolyn , Maximin Suresh
Published: October 2015

Thyroid nodules are often followed up with serial ultrasound imaging. Doubling time is well established in the evaluation of lung nodules. We examined whether benign and malignant thyroid nodules exhibit differences in doubling time.

This retrospective, IRB-approved study included patients with nodules aspirated between January and June 2012 (benign), and January 2012 to December 2014 (suspicious or malignant), no interval thyroidectomy, and two ultrasound examinations longer than 180 days apart. Diameters and morphology were assessed by a single observer, demographics recorded, and doubling time calculated. Area under the receiver operating characteristic curve was derived. Society of Radiologists in Ultrasound criteria were used to determine aspiration appropriateness initially and after follow-up.

59 patients with 61 nodules were included. Statistically significant between-group differences exist for sex, solidity, echogenicity, and microcalcifications, with no significant differences in doubling time, age, days between studies, vascularity, or mean diameter. Benign nodules' doubling time was 340 to 7134 days (mean, 2196; median, 1593), with 9 nodules that decreased in size. Malignant nodules' doubling time was 451 to 17182 days (mean, 3940; median, 2137), with 7 nodules that decreased in size. Using a threshold of 1100 days, sensitivity and specificity of doubling time to predict malignancy are 19.0% and 86.7%, respectively. Area under the receiver operating characteristic curve is 0.39. Follow-up imaging resulted in 6 additional benign and 0 additional malignant nodules meeting criteria.

There is no significant difference in benign or malignant nodules' doubling times, and a decrease in nodule size is nonspecific. These findings challenge the underlying rationale for routine imaging follow-up of thyroid nodules.
A simplified, data-constrained approach to estimate the permafrost carbon–climate feedback
Authors: Koven C. D. , Schuur E. A. G. , Schädel C. , Bohn T. J. , Burke E. J. , Chen G. , Chen X. , Ciais P. , Grosse G. , Harden J. W. , Hayes D. J. , Hugelius G. , Jafarov E. E. , Krinner G. , Kuhry P. , Lawrence D. M. , MacDougall A. H. , Marchenko S. S. , McGuire A. D. , Natali S. M. , Nicolsky D. J. , Olefeldt D. , Peng S. , Romanovsky V. E. , Schaefer K. M. , Strauss J. , Treat C. C. , Turetsky M.
Published: October 2015

We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation–Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2–33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9–112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change (γsensitivity) of −14 to −19 Pg C °C−1on a 100 year time scale. For CH4emissions, our approach assumes a fixed saturated area and that increases in CH4emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH4emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10–18%. The simplified approach presented here neglects many important processes that may amplify or mitigate C release from permafrost soils, but serves as a data-constrained estimate on the forced, large-scale permafrost C response to warming.
Shortwave forcing and feedbacks in Last Glacial Maximum and Mid-Holocene PMIP3 simulations
Authors: Braconnot Pascale , Kageyama Masa
Published: October 2015

Simulations of the climates of the Last Glacial Maximum (LGM), 21 000 years ago, and of the Mid-Holocene (MH), 6000 years ago, allow an analysis of climate feedbacks in climate states that are radically different from today. The analyses of cloud and surface albedo feedbacks show that the shortwave cloud feedback is a major driver of differences between model results. Similar behaviours appear when comparing the LGM and MH simulated changes, highlighting the fingerprint of model physics. Even though the different feedbacks show similarities between the different climate periods, the fact that their relative strength differs from one climate to the other prevents a direct comparison of past and future climate sensitivity. The land-surface feedback also shows large disparities among models even though they all produce positive sea-ice and snow feedbacks. Models have very different sensitivities when considering the vegetation feedback. This feedback has a regional pattern that differs significantly between models and depends on their level of complexity and model biases. Analyses of the MH climate in two versions of the IPSL model provide further indication on the possibilities to assess the role of model biases and model physics on simulated climate changes using past climates for which observations can be used to assess the model results.
Aurantivirga profunda gen. nov., sp. nov., isolated from deep-seawater, a novel member of the family Flavobacteriaceae
Authors: Song Jaeho , Choi Ahyoung , Im Mihye , Joung Yochan , Yoshizawa Susumu , Cho Jang-Cheon , Kogure Kazuhiro
Published: October 2015

A Gram-stain-negative, aerobic, proteorhodopsin-containing, orange, rod-shaped bacterium, designated SAORIC-234T, was isolated from deep seawater in the Pacific Ocean. 16S rRNA gene sequence analysis revealed that the strain could be affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes and shared less than 94.6 % similarity with other species of the family with validly published names. The phenotypic characteristics of this novel isolate, such as growth properties and enzyme activities, could be differentiated from those of other species. The strain was non-motile, oxidase-positive and catalase-negative. The G+C content of the genomic DNA was determined to be 34.8 mol% and menaquinone-6 (MK-6) was the predominant isoprenoid quinone. The predominant fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C16 : 0 3-OH, iso-C17 : 0 3-OH and iso-C15 : 0 3-OH. The major polar lipids comprised phosphatidylethanolamine, three unknown aminolipids and three unknown lipids. On the basis of the taxonomic data collected in this study, it was concluded that strain SAORIC-234T represents a novel genus and species in the family Flavobacteriaceae, for which the name Aurantivirga profunda gen. nov., sp. nov. is proposed. The type strain of the type species, Aurantivirga profunda sp. nov., is SAORIC-234T ( = NBRC 110606T = KACC 18400T).