bluuebunny/crossref_metadata_2025 huggingface dataset:
Terrestrial Sediments of the Earth: Development of a Global Unconsolidated Sediments Map Database (GUM)
Authors: Börker J. , Hartmann J. , Amann T. , Romero‐Mujalli G.
Published: February 2018

Mapped unconsolidated sediments cover half of the global land surface. They are of considerable importance for many Earth surface processes like weathering, hydrological fluxes or biogeochemical cycles. Ignoring their characteristics or spatial extent may lead to misinterpretations in Earth System studies. Therefore, a new Global Unconsolidated Sediments Map database (GUM) was compiled, using regional maps specifically representing unconsolidated and quaternary sediments. The new GUM database provides insights into the regional distribution of unconsolidated sediments and their properties. The GUM comprises 911,551 polygons and describes not only sediment types and subtypes, but also parameters like grain size, mineralogy, age and thickness where available. Previous global lithological maps or databases lacked detail for reported unconsolidated sediment areas or missed large areas, and reported a global coverage of 25 to 30%, considering the ice‐free land area. Here, alluvial sediments cover about 23% of the mapped total ice‐free area, followed by aeolian sediments (∼21%), glacial sediments (∼20%), and colluvial sediments (∼16%). A specific focus during the creation of the database was on the distribution of loess deposits, since loess is highly reactive and relevant to understand geochemical cycles related to dust deposition and weathering processes. An additional layer compiling pyroclastic sediment is added, which merges consolidated and unconsolidated pyroclastic sediments. The compilation shows latitudinal abundances of sediment types related to climate of the past. The GUM database is available at the PANGAEA database (https://doi.org/10.1594/PANGAEA.884822).
Northern Galápagos Corals Reveal Twentieth Century Warming in the Eastern Tropical Pacific
Authors: Jimenez Gloria , Cole Julia E. , Thompson Diane M. , Tudhope Alexander W.
Published: February 2018

Models and observations disagree regarding sea surface temperature (SST) trends in the eastern tropical Pacific. We present a new Sr/Ca‐SST record that spans 1940–2010 from two Wolf Island corals (northern Galápagos). Trend analysis of the Wolf record shows significant warming on multiple timescales, which is also present in several other records and gridded instrumental products. Together, these data sets suggest that most of the eastern tropical Pacific has warmed over the twentieth century. In contrast, recent decades have been characterized by warming during boreal spring and summer (especially north of the equator), and subtropical cooling during boreal fall and winter (especially south of the equator). These SST trends are consistent with the effects of radiative forcing, mitigated by cooling due to wind forcing during boreal winter, as well as intensified upwelling and a strengthened Equatorial Undercurrent.
Abyssal Upwelling in Mid‐Ocean Ridge Fracture Zones
Authors: Clément Louis , Thurnherr Andreas M.
Published: February 2018

Turbulence in the abyssal ocean plays a fundamental role in the climate system by sustaining the deepest branch of the overturning circulation. Over the western flank of the Mid‐Atlantic Ridge in the South Atlantic, previously observed bottom‐intensified and tidally modulated mixing of abyssal waters appears to imply a counterintuitive densification of deep and bottom waters. Here we show that inside fracture zones, however, turbulence is elevated away from the seafloor because of intensified downward propagating near‐inertial wave energy, which decays below a subinertial shear maximum. Ray‐tracing simulations predict a decay of wave energy subsequent to wave‐mean flow interactions. The hypothesized wave‐mean flow interactions drive a deep flow toward lighter densities of up to 0.6 Sv over the mid‐ocean ridge flank in the Brazil Basin, and the same process may also cause upwelling of abyssal waters in other ocean basins with mid‐ocean ridges with fracture zones.
Atlantic Multidecadal Oscillation Modulates the Impacts of Arctic Sea Ice Decline
Authors: Li Fei , Orsolini Yvan J. , Wang Huijun , Gao Yongqi , He Shengping
Published: February 2018

The Arctic sea ice cover has been rapidly declining in the last two decades, concurrent with a shift in the Atlantic Multidecadal Oscillation (AMO) to its warm phase around 1996/1997. Here we use both observations and model simulations to investigate the modulation of the atmospheric impacts of the decreased sea ice cover in the Atlantic sector of the Arctic (AASIC) by the AMO. We find that the AASIC loss during a cold AMO phase induces increased Ural blocking activity, a southeastward‐extended snowpack, and a cold continent anomaly over Eurasia in December through northerly cold air advection and moisture transport from the Arctic. The increased Ural blocking activity and more extended Eurasian snowpack strengthen the upward propagation of planetary waves over the Siberian‐Pacific sector in the lower stratosphere and hence lead to a weakened stratospheric polar vortex and a negative Arctic Oscillation (AO) phase at the surface in February. However, corresponding to the AASIC loss during a warm AMO phase, one finds more widespread warming over the Arctic and a reduced snowpack over Northern Eurasia in December. The stratosphere‐troposphere coupling is suppressed in early winter and no negative AO anomaly is found in February. We suggest that the cold AMO phase is important to regulate the atmospheric response to AASIC decline, and our study provides insight to the ongoing debate on the connection between the Arctic sea ice and the AO.
Transmissivity Changes and Microseismicity Induced by Small‐Scale Hydraulic Fracturing Tests in Crystalline Rock
Authors: Jalali Mohammadreza , Gischig Valentin , Doetsch Joseph , Näf Rico , Krietsch Hannes , Klepikova Maria , Amann Florian , Giardini Domenico
Published: February 2018

Multiple meter‐scale hydraulic fracturing (HF) experiments were executed in the crystalline rock at the Grimsel Test Site, Switzerland. The effect of the HF on the rock transmissivity has been quantified with hydraulic tests before and after each HF experiment. We observe transmissivity enhancement of 2 to 3 orders of magnitude and a change in the dominant flow regime after most of the HF tests. From microseismicity induced by the HF, we do not observe a systematic correlation between transmissivity enhancement and event numbers, frequency‐magnitude distribution, or maximum magnitude. However, the radii of hydraulic fractures inferred independently from seismicity clouds and hydraulic responses coincide, implying that slip along fractures is the common underlying mechanism for transmissivity increase and seismicity.
Evaluating Surface Radiation Fluxes Observed From Satellites in the Southeastern Pacific Ocean
Authors: Pinker R. T. , Zhang B. , Weller R. A. , Chen W.
Published: February 2018

This study is focused on evaluation of current satellite and reanalysis estimates of surface radiative fluxes in a climatically important region. It uses unique observations from the STRATUS Ocean Reference Station buoy in a region of persistent marine stratus clouds 1,500 km off northern Chile during 2000–2012. The study shows that current satellite estimates are in better agreement with buoy observations than model outputs at a daily time scale and that satellite data depict well the observed annual cycle in both shortwave and longwave surface radiative fluxes. Also, buoy and satellite estimates do not show any significant trend over the period of overlap or any interannual variability. This verifies the stability and reliability of the satellite data and should make them useful to examine El Niño–Southern Oscillation variability influences on surface radiative fluxes at the STRATUS site for longer periods for which satellite record is available.
Urban Modification of Convection and Rainfall in Complex Terrain
Authors: Freitag B. M. , Nair U. S. , Niyogi D.
Published: February 2018

Despite a globally growing proportion of cities located in regions of complex terrain, interactions between urbanization and complex terrain and their meteorological impacts are not well understood. We utilize numerical model simulations and satellite data products to investigate such impacts over San Miguel de Tucumán, Argentina. Numerical modeling experiments show urbanization results in 20–30% less precipitation downwind of the city and an eastward shift in precipitation upwind. Our experiments show that changes in surface energy, boundary layer dynamics, and thermodynamics induced by urbanization interact synergistically with the persistent forcing of atmospheric flow by complex terrain. With urbanization increasing in mountainous regions, land‐atmosphere feedbacks can exaggerate meteorological forcings leading to weather impacts that require important considerations for sustainable development of urban regions within complex terrain.
Fault Rupture Model of the 2016 Gyeongju, South Korea, Earthquake and Its Implication for the Underground Fault System
Authors: Uchide Takahiko , Song Seok Goo
Published: February 2018

The 2016 Gyeongju earthquake (ML 5.8) was the largest instrumentally recorded inland event in South Korea. It occurred in the southeast of the Korean Peninsula and was preceded by a large ML 5.1 foreshock. The aftershock seismicity data indicate that these earthquakes occurred on two closely collocated parallel faults that are oblique to the surface trace of the Yangsan fault. We investigate the rupture properties of these earthquakes using finite‐fault slip inversion analyses. The obtained models indicate that the ruptures propagated NNE‐ward and SSW‐ward for the main shock and the large foreshock, respectively. This indicates that these earthquakes occurred on right‐step faults and were initiated around a fault jog. The stress drops were up to 62 and 43 MPa for the main shock and the largest foreshock, respectively. These high stress drops imply high strength excess, which may be overcome by the stress concentration around the fault jog.
A Case Study of Connection Between Ground Magnetic Field Perturbations and Tail Current Sheet Bursty Flows at X = −60 RE
Authors: Wang Chih‐Ping , Xing Xiaoyan , Liu Yi‐Hsin , Runov Andrei
Published: February 2018

We report the first observations that connect a burst of fast flows and Pi2 fluctuations in the midtail current sheet at X ~ −60 RE with ground magnetic negative bays and Pi2 pulsations at high latitudes near 70°. Both the flow burst and negative bays occurred around midnight and were isolated and lasted for ~10 min. The flow burst had the characteristics of a low‐density plasma bubble. It was moving earthward at ~340 km/s and was accompanied by field‐aligned currents. The timing and equatorward motion of magnetic bays can be accounted for by this earthward moving bubble. Enhanced Pi2 fluctuations were observed within both the bubble and the magnetic bays. Pressure anisotropy with higher parallel pressure was observed associated with the flow burst and was firehose unstable. We discuss firehose instability as one of the possible mechanisms for the Pi2 fluctuations.
CT Identification and Fractal Characterization of 3‐D Propagation and Distribution of Hydrofracturing Cracks in Low‐Permeability Heterogeneous Rocks
Authors: Liu Peng , Ju Yang , Gao Feng , Ranjith Pathegama G. , Zhang Qianbing
Published: February 2018

Understanding and characterization of the three‐dimensional (3‐D) propagation and distribution of hydrofracturing cracks in heterogeneous rock are key for enhancing the stimulation of low‐permeability petroleum reservoirs. In this study, we investigated the propagation and distribution characteristics of hydrofracturing cracks, by conducting true triaxial hydrofracturing tests and computed tomography on artificial heterogeneous rock specimens. Silica sand, Portland cement, and aedelforsite were mixed to create artificial heterogeneous rock specimens using the data of mineral compositions, coarse gravel distribution, and mechanical properties that were measured from the natural heterogeneous glutenite cores. To probe the effects of material heterogeneity on hydrofracturing cracks, the artificial homogenous specimens were created using the identical matrix compositions of the heterogeneous rock specimens and then fractured for comparison. The effects of horizontal geostress ratio on the 3‐D growth and distribution of cracks during hydrofracturing were examined. A fractal‐based method was proposed to characterize the complexity of fractures and the efficiency of hydrofracturing stimulation of heterogeneous media. The material heterogeneity and horizontal geostress ratio were found to significantly influence the 3‐D morphology, growth, and distribution of hydrofracturing cracks. A horizontal geostress ratio of 1.7 appears to be the upper limit for the occurrence of multiple cracks, and higher ratios cause a single crack perpendicular to the minimum horizontal geostress component. The fracturing efficiency is associated with not only the fractured volume but also the complexity of the crack network.
The Character of South Pole‐Aitken Basin: Patterns of Surface and Subsurface Composition
Authors: Moriarty D. P. , Pieters C. M.
Published: February 2018

Using Moon Mineralogy Mapper data, we characterize surface diversity across the enormous South Pole‐Aitken Basin (SPA) by evaluating the abundance and composition of pyroxenes, which are overwhelmingly the most abundant mafic mineral in the region. Although SPA exhibits significant complexity due to billions of years of geologic processes subsequent to formation, the basin has retained regular patterns of compositional heterogeneity across its structure. Four distinct, roughly concentric zones are defined: (1) a central SPA compositional anomaly, which exhibits a pervasive elevated Ca,Fe‐rich pyroxene abundance; (2) a Mg‐pyroxene annulus, which is dominated by abundant Mg‐rich pyroxenes; (3) a heterogeneous annulus, which exhibits localized pyroxene‐rich areas spatially mixed with feldspathic materials; and (4) the SPA exterior, which is primarily feldspathic. Pyroxene compositions in the heterogeneous annulus are similar to those in the Mg‐pyroxene annulus, and Mg‐rich pyroxenes also underlie the more Ca,Fe‐rich pyroxene surface material across the SPA compositional anomaly. The establishment of these four distinct compositional zones across SPA constrains basin evolution models and serves to guide potential sample return (and other science) targets.
The Effects of H2SO4 on the Mechanical Behavior and Microstructural Evolution of Polycrystalline Ice
Authors: Hammonds Kevin , Baker Ian
Published: February 2018

The Earth's large continental ice sheets contain a variety of naturally occurring impurities, both soluble and insoluble. Understanding how these impurities affect the rheology, intrinsic thermodynamic properties, and fate of these ice sheets is not well understood. To investigate the effects that trace amounts of H2SO4 have on the flow and ductility of polycrystalline ice, a series of mechanical tests were conducted at −6, −10, −12.5, and −20°C using laboratory‐prepared specimens of polycrystalline ice doped with 1–15 ppm of H2SO4. Parallel tests were performed on identical but undoped specimens of polycrystalline ice. Mechanical testing included constant‐load tensile creep tests at an initial stress of 0.75 MPa and compression tests at constant displacement rates with initial strain rates ranging from 1 × 10−6 to 1 × 10−4 s−1. It was found that H2SO4‐doped specimens of ice exhibited faster creep rates in tension and significantly lower peak stresses in compression, when compared to the undoped ice. Postmortem microstructural analyses were performed using cross‐polarized light thin section imaging, X‐ray computed microtomography, Raman spectroscopy, and electron backscatter diffraction. These analyses showed that H2SO4‐doped specimens had a larger grain size at strains ≤15%, and an earlier onset of microcracking at lower strain rates than the undoped ice. Strain‐induced grain boundary migration was found to be the predominant mechanism of recrystallization in both doped and undoped specimens. Further, an aqueous phase of H2SO4 was found to exist at the grain boundaries and triple junctions of the doped ice, which is thought to have significantly contributed toward its reduced viscosity.
Power Flow, Energy Density, and Group/Energy Transport Velocities in Spatially Dispersive Media
Authors: Yaghjian Arthur D.
Published: February 2018

Electromagnetic power flow, energy density, and the energy transport velocity that equals the group velocity of a lossless wave packet are straightforwardly derived for the recently formulated electric and magnetic anisotropic representation of spatially dispersive materials or metamaterials. Boundary conditions in spatially dispersive media are used to confirm analytically and numerically the expressions obtained for the power flow and energy density. A long‐standing alternative expression for the energy transport velocity in spatially dispersive media is shown to be invalid. Plausible formulation‐independent definitions of spatial and temporal dispersion for normal modes are proposed in terms of group and phase velocities.
Intrusion of Magmatic Bodies Into the Continental Crust: 3‐D Numerical Models
Authors: Gorczyk Weronika , Vogt Katharina
Published: February 2018

Magma intrusion is a major material transfer process in the Earth's continental crust. Yet the mechanical behavior of the intruding magma and its host are a matter of debate. In this study we present a series of numerical thermomechanical simulations on magma emplacement in 3‐D. Our results demonstrate the response of the continental crust to magma intrusion. We observe change in intrusion geometries between dikes, cone sheets, sills, plutons, ponds, funnels, finger‐shaped and stock‐like intrusions, and injection time. The rheology and temperature of the host are the main controlling factors in the transition between these different modes of intrusion. Viscous deformation in the warm and deep crust favors host rock displacement and plutons at the crust‐mantle boundary forming deep‐seated plutons or magma ponds in the lower to middle crust. Brittle deformation in the cool and shallow crust induces cone‐shaped fractures in the host rock and enables emplacement of finger‐ or stock‐like intrusions at shallow or intermediate depth. Here the passage of magmatic and hydrothermal fluids from the intrusion through the fracture pattern may result in the formation of ore deposits. A combination of viscous and brittle deformation forms funnel‐shaped intrusions in the middle crust. Intrusion of low‐density magma may more over result in T‐shaped intrusions in cross section with magma sheets at the surface.
Reply to Comment by Vincent et al.
Authors: Cowgill Eric , Niemi Nathan A. , Forte Adam M. , Trexler Charles C.
Published: February 2018

Key Points

The Greater Caucasus Basin encompassed a broader region than envisioned by Vincent et al., who disregard Cenozoic shortening

Terminal basin closure occurred when the Greater and Lesser Caucasus collided

Data cited by Vincent et al. document the onset of basin closure by 35 Ma, but do not indicate terminal basin closure at this time
Early Cenozoic Denudation of Central West Britain in Response to Transient and Permanent Uplift Above a Mantle Plume
Authors: Łuszczak K. , Persano C. , Stuart F. M.
Published: February 2018

Upwelling mantle plumes beneath continental crust are predicted to produce difficult to quantify, modest uplift and denudation. The contribution of permanent and transient components to the uplift is also difficult to distinguish. A pulse of denudation in Britain in the Early Paleogene has been linked, although with some controversy, with the arrival of the proto‐Iceland mantle plume. In this contribution we show that combining apatite and zircon (U‐Th‐Sm)/He and apatite fission track analyses from central west Britain with numerical modeling clearly identifies a pulse of early Cenozoic denudation. The data indicate that rock uplift and denudation were centered on the northern East Irish Sea Basin and 1.0–2.4 km of rocks were removed during the latest Cretaceous‐early Paleogene. Uplift and erosion appears to have started a few million years before the earliest magmatism in the region. The regional denudation pattern mirrors the distribution of low‐density magmatic rocks that has been imaged in the deep crust. However, the injection of the underplating melt is not enough to account for the total denudation. An additional regional uplift of at least 300 m is required, which is consistent with a transient thermal effect from the hot mantle plume. The rapid exhumation event ceased by ~40 Ma and the data do not require significant Neogene exhumation.
Three‐Dimensional Modeling of Mount Etna Volcano: Volume Assessment, Trend of Eruption Rates, and Geodynamic Significance
Authors: Barreca Giovanni , Branca Stefano , Monaco Carmelo
Published: February 2018

3‐D modeling of Mount Etna, the largest and most active volcano in Europe, has for the first time enabled acquiring new information on the volumes of products emitted during the volcanic phases that have formed Mount Etna and particularly during the last 60 ka, an issue previously not fully addressed. Volumes emitted over time allow determining the trend of eruption rates during the volcano's lifetime, also highlighting a drastic increase of emitted products in the last 15 ka. The comparison of Mount Etna's eruption rates with those of other volcanic systems in different geodynamic frameworks worldwide revealed that since 60 ka ago, eruption rates have reached a value near to that of oceanic‐arc volcanic systems, although Mount Etna is considered a continental rift strato‐volcano. This finding agrees well with previous studies on a possible transition of Mount Etna's magmatic source from plume‐related to island‐arc related. As suggested by tomographic studies, trench‐parallel breakoff of the Ionian slab has occurred north of Mount Etna. Slab gateway formation right between the Aeolian magmatic province and the Mount Etna area probably induced a previously softened and fluid‐enriched suprasubduction mantle wedge to flow toward the volcano with consequent magmatic source mixing.
Evidence for the Influence of DE3 Tide on the Occurrence of Equatorial Counterelectrojet
Authors: Singh Dupinder , Gurubaran S. , He Maosheng
Published: February 2018

The long‐term Challenging Minisatellite Payload magnetometer data are analyzed to derive the equatorial counterelectrojet (CEJ) signatures globally over a range of local times. The resultant local time‐longitude map of CEJ occurrence rate shows a strong influence of the diurnal eastward propagating wave number 3 (DE3) nonmigrating tide during July–September months. DE3 is also shown to account for the reduction of CEJ occurrence at certain longitudes. These aspects of DE3 tide‐CEJ relationship have implications for understanding the seasonal and longitudinal variations of CEJ. Observations of zonal winds from the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) Doppler Interferometer instrument on board the TIMED satellite are used to establish these findings.
Very High Frequency Radio Emissions Associated With the Production of Terrestrial Gamma‐Ray Flashes
Authors: Lyu Fanchao , Cummer Steven A. , Krehbiel Paul R. , Rison William , Briggs Michael S. , Cramer Eric , Roberts Oliver , Stanbro Matthew
Published: February 2018

Recent studies of the close association between terrestrial gamma‐ray flashes (TGFs) production and simultaneous lightning processes have shown that many TGFs are produced during the initial leader of intracloud flashes and that some low‐frequency (LF) radio emissions may directly come from TGF itself. Measurements of any simultaneous very high frequency (VHF) radio emissions would give important insight into any lightning leader dynamics that are associated with TGF generation, and thus, such measurements are needed. Here we report on coordinated observations of TGFs detected simultaneously by Fermi Gamma‐ray Burst Monitor, two VHF lightning mapping arrays, and Duke ground‐based LF radio sensors to investigate more on the close association between TGFs and LF and VHF radio emissions. Three TGFs are analyzed here and confirm previous findings on the close association between TGF generation and lightning processes and, for the first time, provide time‐aligned measurements of the VHF radio signature within a few tens of microseconds of TGF generation. Strong VHF emissions were observed essentially simultaneously with two TGFs and within a few tens of microseconds of a third TGF. Equally importantly, the VHF measurement details indicate that the TGF‐associated emissions are nonimpulsive and extended in time. We conclude that the TGF‐producing process is at least sometimes closely associated with strong VHF emissions, and thus, there may be a link between the generation of TGFs and active lightning streamer dynamics.
A Framework to Study Mixing Processes in the Marine Boundary Layer Using Water Vapor Isotope Measurements
Authors: Benetti M. , Lacour J.‐L. , Sveinbjörnsdóttir A. E. , Aloisi G. , Reverdin G. , Risi C. , Peters A. J. , Steen‐Larsen H. C.
Published: February 2018

We propose a framework using water vapor isotopes to study mixing processes in the marine boundary layer (MBL) during quiescent conditions, where we expect evaporation to contribute to the moisture budget. This framework complements the existing models, by taking into account the changing isotopic composition of the evaporation flux (δe), both directly in response to the mixing and indirectly in response to mixing and surface conditions through variations in MBL humidity. The robustness of the model is demonstrated using measurements from the North Atlantic Ocean. This shows the importance of considering the δe variability simultaneous to the mixing of the lower free troposphere to the MBL, to simulate the MBL water vapor, whereas a mixing model using a constant δe fails to reproduce the data. The sensitivity of isotope observations to evaporation and shallow mixing further demonstrates how these observations can constrain uncertainties associated with these key processes for climate feedback predictions.
Nondestructive Optical Toxicity Assays of 3D Liver Spheroids with Optical Coherence Tomography
Authors: Martucci Nicole J. , Morgan Katie , Anderson Graham W. , Hayes Peter C. , Plevris John N. , Nelson Leonard J. , Bagnaninchi Pierre O.
Published: February 2018

Drug‐induced liver injury (DILI) is the leading cause of failure in preclinical drug development and withdrawals. Given the central role of the liver in drug metabolism and detoxification, strong incentives exist to create new physiologically relevant, human‐based, 3D in vitro liver models which will offer better prediction of DILI. However, most cell metabolic assays are designed for 2D culture and are not always suitable to assess 3D cultures; in addition, there is an emerging need to develop novel nondestructive assays to assess cell activity in a time‐lapse fashion. In this study, optical coherence tomography (OCT) is used to measure the viability on 3D liver spheroids after acetaminophen exposure used as a model of DILI. Using HepaRG cells, 3D liver spheroids are grown simultaneously to the conventional 2D DILI model for 9 d and are exposed to 5, 10, 20, and 40 × 10−3
m acetaminophen for 24 h. It is shown that OCT can image noninvasively, and label free, the cell metabolic activity, thus enabling the assessment of viability of the 3D spheroids. This correlates well with cellular metabolic activity measured by biochemical assays. This method is translatable to any 3D tissue model and can be performed using any commercial OCT system.
A Simple, General Synthetic Route toward Nanoscale Transition Metal Borides
Authors: Jothi Palani R. , Yubuta Kunio , Fokwa Boniface P. T.
Published: February 2018

Most nanomaterials, such as transition metal carbides, phosphides, nitrides, chalcogenides, etc., have been extensively studied for their various properties in recent years. The similarly attractive transition metal borides, on the contrary, have seen little interest from the materials science community, mainly because nanomaterials are notoriously difficult to synthesize. Herein, a simple, general synthetic method toward crystalline transition metal boride nanomaterials is proposed. This new method takes advantage of the redox chemistry of Sn/SnCl2, the volatility and recrystallization of SnCl2 at the synthesis conditions, as well as the immiscibility of tin with boron, to produce crystalline phases of 3d, 4d, and 5d transition metal nanoborides with different morphologies (nanorods, nanosheets, nanoprisms, nanoplates, nanoparticles, etc.). Importantly, this method allows flexibility in the choice of the transition metal, as well as the ability to target several compositions within the same binary phase diagram (e.g., Mo2B, α‐MoB, MoB2, Mo2B4). The simplicity and wide applicability of the method should enable the fulfillment of the great potential of this understudied class of materials, which show a variety of excellent chemical, electrochemical, and physical properties at the microscale.
Tattoo‐Paper Transfer as a Versatile Platform for All‐Printed Organic Edible Electronics
Authors: Bonacchini Giorgio E. , Bossio Caterina , Greco Francesco , Mattoli Virgilio , Kim Yun‐Hi , Lanzani Guglielmo , Caironi Mario
Published: February 2018

The use of natural or bioinspired materials to develop edible electronic devices is a potentially disruptive technology that can boost point‐of‐care testing. The technology exploits devices that can be safely ingested, along with pills or even food, and operated from within the gastrointestinal tract. Ingestible electronics can potentially target a significant number of biomedical applications, both as therapeutic and diagnostic tool, and this technology may also impact the food industry, by providing ingestible or food‐compatible electronic tags that can “smart” track goods and monitor their quality along the distribution chain. Temporary tattoo‐paper is hereby proposed as a simple and versatile platform for the integration of electronics onto food and pharmaceutical capsules. In particular, the fabrication of all‐printed organic field‐effect transistors on untreated commercial tattoo‐paper, and their subsequent transfer and operation on edible substrates with a complex nonplanar geometry is demonstrated.
Germanium Template Assisted Integration of Gallium Arsenide Nanocrystals on Silicon: A Versatile Platform for Modern Optoelectronic Materials
Authors: Schmitt Sebastian W. , Sarau George , Speich Claudia , Döhler Gottfried H. , Liu Ziheng , Hao Xiaojing , Rechberger Stefanie , Dieker Christel , Spiecker Erdmann , Prost Werner , Tegude Franz J. , Conibeer Gavin , Green Martin A. , Christiansen Silke H.
Published: February 2018

Metal organic vapor phase epitaxy is used to grow gallium arsenide (GaAs) nanocrystals (NCs) on germanium (Ge) templates on nanoscopic silicon (Si) threads prepared by reactive ion etching. Scanning transmission electron microscopy with energy dispersive X‐ray measurements shows an epitaxial growth of the GaAs on the Ge template that is supported by the Si thread, and that Ge doping is induced to the GaAs by the template. On Ge templates of about 60 nm diameter, as‐grown GaAs NCs show a very regular rhombic‐dodecahedral outer shape that can be explained by a preferential growth along the <110> plane. Photoluminescence measurements of the Ge/GaAs structures reveal radiative emission peaks on top of the GaAs band‐to‐band emission and at sub‐band gap energies. While high energy peaks are originating from Ge acceptor levels in GaAs, sub‐band gap peaks can be explained by radiation from Ge donor and acceptor bands that are amplified by photonic modes hosted in the rhombic‐dodecahedral GaAs NCs. This study shows that a template‐assisted crystal growth at the nanoscale opens up routes for a versatile integration of strongly emitting nanomaterials for a use in on‐chip solid state lighting and photonics.
Giant and Linear Piezo‐Phototronic Response in Layered GaSe Nanosheets
Authors: Jia Tanhua , Fuh Huei‐Ru , Chen Dengyun , Abid Mohamed , Abid Mourad , Zhang Duan , Sarker Anas B. , Cho Jiung , Choi Miri , Chun Byong Sun , Xu Hongjun , Ó Coileáin Cormac , Liu Huajun , Chang Ching‐Ray , Wu Han‐Chun
Published: February 2018

Piezo‐phototronic devices, where optoelectrical properties are directly influenced by mechanical stimuli, are highly desirable for applications in wearable devices and human–machine interfaces. Here, the piezoelectric and piezo‐phototronic properties of GaSe nanosheets, a layered metal‐monochalcogenide III–VI semiconductor with interesting piezoelectric, optical excitation, and semiconducting properties are investigated. A giant piezo‐phototronic response in GaSe is demonstrated for the first time. The out‐of‐plane local field due to band gap modulation drives the electrons (holes) to move toward the outer (inner) surface of wrinkles, which enhances electron–hole pair generation and the related photocurrent. Moreover, manual bending of GaSe reliably enhances the photocurrent by more than a factor of 50 at room temperature. This giant and linear piezo‐phototronic response combined with excellent stretchability suggests that GaSe is a valuable material for flexible optoelectronic‐mechanical applications.
Emergency Medicine Residency Selection Criteria: An Update and Comparison
Authors: Negaard Matthew , Assimacopoulos Evangelia , Harland Karisa , Van Heukelom Jon
Published: February 2018

Objective

The primary objective was to describe emergency medicine (EM) residency selection criteria.

Methods

A survey was sent to the Council of Emergency Medicine Residency Directors listserv. Respondents were asked to rank order the various components of the application on a Likert scale from 1 (minimally important) to 10 (highly important). The mean ranking and standard deviation for each of the components were calculated. The survey sought to determine characteristics associated with offering an applicant an invitation to interview and subsequent ranking. Percentages with defined minimum requirements were calculated. Comparisons across residency length and location were completed with a Pearson chi‐square test for categorical variables and Student's t‐test for continuous variables.

Results

A total of 120 surveys were completed. The highest ranked components included away/visiting institution departmental standardized letter of evaluation (SLOE) (mean ± SD = 8.80 ± 1.25), residency interview (mean ± SD = 8.74 ± 1.28), home institution departmental SLOE (mean ± SD = 8.61 ± 1.18), away/visiting institution EM rotation grade (mean ± SD = 8.29 ± 1.43), and home institution EM rotation grade (mean ± SD = 8.07 ± 1.42). The most consistently ranked items included home institution departmental SLOE (SD = 1.18), away/visiting institution departmental SLOE (1.25), and residency interview (1.28). Characteristics associated with offering an interview to an applicant included only 10% of responses indicating a United States Medical Licensing Examination Step 1 score of 220 was needed. At least one SLOE was required in 80% of responses. Program location was related to the number of SLOEs required (p = 0.03). Length of residency and program location differed significantly in how a residency ranked components when considering an applicant (p < 0.05).

Conclusion

Emergency medicine programs put high value in departmental SLOEs, the interview, and EM rotation grades when selecting potential residents. Higher value is placed on SLOEs and grades from away/visiting institutions compared with students’ home institutions.
Rhesus macaque personality, dominance, behavior, and health
Authors: Robinson Lauren M. , Coleman Kristine , Capitanio John P. , Gottlieb Daniel H. , Handel Ian G. , Adams Mark J. , Leach Matthew C. , Waran Natalie K. , Weiss Alexander
Published: February 2018

Previous studies of nonhuman primates have found relationships between health and individual differences in personality, behavior, and social status. However, despite knowing these factors are intercorrelated, many studies focus only on a single measure, for example, rank. Consequently, it is difficult to determine the degree to which these individual differences are independently associated with health. The present study sought to untangle the associations between health and these individual differences in rhesus macaques (Macaca mulatta). We studied 85 socially housed macaques at the Oregon and California National Primate Research Centers, and used veterinary records to determine the number of injuries and illnesses for each macaque. We measured personality using 12 items from a well‐established primate personality questionnaire, performed focal observations of behaviors, and calculated dominance status from directional supplant data. All twelve personality questionnaire items were reliable and were used to represent five of the six personality dimensions identified in rhesus macaques—Dominance, Confidence, Openness, Anxiety, and Friendliness (also known as Sociability). Following this, we fit generalized linear mixed effects models to understand how these factors were associated with an animal's history of injury and history of illness. In the models, age was an offset, facility was a random effect, and the five personality dimensions, behavior, sex, and dominance status were fixed effects. Number of injuries and illnesses were each best represented by a negative binomial distribution. For the injury models, including the effects did improve model fit. This model revealed that more confident and more anxious macaques experienced fewer injuries. For the illness models, including the fixed effects did not significantly improve model fit over a model without the fixed effects. Future studies may seek to assess mechanisms underlying these associations.
The impact of video nasal endoscopy on patient satisfaction
Authors: Bhalla Vidur , Beahm D. David , Sykes Kevin J. , Ndeti Kavindu K. , Chiu Alexander G.
Published: February 2018

Background

Video nasal endoscopy has significant associated expense for practices, but its use has been justified by the benefit it provides to the examiner. No study has examined the perceived benefit to the patient. In this study, the impact of video endoscopy on patient satisfaction is evaluated.

Methods

A prospective, randomized, single‐blinded study was performed on new patients receiving care in the rhinology clinics of a tertiary‐care center. Patients were randomized into the standard endoscopic examination (SEE) or video endoscopic examination (VEE) groups. SEE patients had their examination performed with the physician viewing the exam through the eyepiece, without a video camera, and subsequently had their examination explained. VEE patients had their examination performed with a video camera attached to the scope, recorded, and then used for the explanation. All patients were asked to complete the 22‐item Sino‐Nasal Outcome Test (SNOT‐22) and the 18‐item Patient Satisfaction Questionnaire Short‐Form (PSQ‐18). Statistical analysis was performed to identify differences between cohorts.

Results

There was no significant demographic difference between groups. SNOT‐22 total and domain scores were similar between both groups (p > 0.05). VEE patients had significantly higher general satisfaction (p = 0.048) and communication (p = 0.028) domains within the PSQ‐18. There was no difference between other domains (p > 0.05).

Conclusion

VEE is a valuable tool for otolaryngologists and patients. Further studies evaluating variance in patient compliance and symptomatology may provide further justification for its use.
Site‐Specific Studies of Nucleosome Interactions by Solid‐State NMR Spectroscopy
Authors: Xiang ShengQi , le Paige Ulric B. , Horn Velten , Houben Klaartje , Baldus Marc , van Ingen Hugo
Published: February 2018

Chromatin function depends on a dense network of interactions between nucleosomes and a wide range of proteins. A detailed description of these protein–nucleosome interactions is required to reach a full molecular understanding of chromatin function in both genetics and epigenetics. Herein, we show that the structure, dynamics, and interactions of nucleosomes can be interrogated in a residue‐specific manner by using state‐of‐the‐art solid‐state NMR spectroscopy. Using sedimented nucleosomes, high‐resolution spectra were obtained for both flexible histone tails and the non‐mobile histone core. Through co‐sedimentation of a nucleosome‐binding peptide, we demonstrate that protein‐binding sites on the nucleosome surface can be determined. We believe that this approach holds great promise as it is generally applicable, extendable to include the structure and dynamics of the bound proteins, and scalable to interactions of proteins with higher‐order chromatin structures, including isolated and cellular chromatin.
Promoted Fixation of Molecular Nitrogen with Surface Oxygen Vacancies on Plasmon‐Enhanced TiO2 Photoelectrodes
Authors: Li Chengcheng , Wang Tuo , Zhao Zhi‐Jian , Yang Weimin , Li Jian‐Feng , Li Ang , Yang Zhilin , Ozin Geoffrey A. , Gong Jinlong
Published: February 2018

A hundred years on, the energy‐intensive Haber–Bosch process continues to turn the N2 in air into fertilizer, nourishing billions of people while causing pollution and greenhouse gas emissions. The urgency of mitigating climate change motivates society to progress toward a more sustainable method for fixing N2 that is based on clean energy. Surface oxygen vacancies (surface Ovac) hold great potential for N2 adsorption and activation, but introducing Ovac on the very surface without affecting bulk properties remains a great challenge. Fine tuning of the surface Ovac by atomic layer deposition is described, forming a thin amorphous TiO2 layer on plasmon‐enhanced rutile TiO2/Au nanorods. Surface Ovac in the outer amorphous TiO2 thin layer promote the adsorption and activation of N2, which facilitates N2 reduction to ammonia by excited electrons from ultraviolet‐light‐driven TiO2 and visible‐light‐driven Au surface plasmons. The findings offer a new approach to N2 photofixation under ambient conditions (that is, room temperature and atmospheric pressure).
Dual‐Input Regulation and Positional Control in Hybrid Oligonucleotide/Discotic Supramolecular Wires
Authors: Alemán García Miguel Ángel , Magdalena Estirado Eva , Milroy Lech‐Gustav , Brunsveld Luc
Published: February 2018

The combination of oligonucleotides and synthetic supramolecular systems allows for novel and long‐needed modes of regulation of the self‐assembly of both molecular elements. Discotic molecules were conjugated with short oligonucleotides and their assembly into responsive supramolecular wires studied. The self‐assembly of the discotic molecules provides additional stability for DNA‐duplex formation owing to a cooperative effect. The appended oligonucleotides allow for positional control of the discotic elements within the supramolecular wire. The programmed assembly of these hybrid architectures can be modulated through the DNA, for example, by changing the number of base pairs or salt concentration, and through the discotic platform by the addition of discotic elements without oligonucleotide handles. These hybrid supramolecular‐DNA structures allow for advanced levels of control over 1D dynamic platforms with responsive regulatory elements at the interface with biological systems.
Super‐Chelators for Advanced Protein Labeling in Living Cells
Authors: Gatterdam Karl , Joest Eike F. , Dietz Marina S. , Heilemann Mike , Tampé Robert
Published: February 2018

Live‐cell labeling, super‐resolution microscopy, single‐molecule applications, protein localization, or chemically induced assembly are emerging approaches, which require specific and very small interaction pairs. The minimal disturbance of protein function is essential to derive unbiased insights into cellular processes. Herein, we define a new class of hexavalent N‐nitrilotriacetic acid (hexaNTA) chelators, displaying the highest affinity and stability of all NTA‐based small interaction pairs described so far. Coupled to bright organic fluorophores with fine‐tuned photophysical properties, the super‐chelator probes were delivered into human cells by chemically gated nanopores. These super‐chelators permit kinetic profiling, multiplexed labeling of His6‐ and His12‐tagged proteins as well as single‐molecule‐based super‐resolution imaging.
Literally Green Chemical Synthesis of Artemisinin from Plant Extracts
Authors: Triemer Susann , Gilmore Kerry , Vu Giang T. , Seeberger Peter H. , Seidel‐Morgenstern Andreas
Published: February 2018

Active pharmaceutical ingredients are either extracted from biological sources—where they are synthesized in complex, dynamic environments—or prepared in stepwise chemical syntheses by reacting pure reagents and catalysts under controlled conditions. A combination of these two approaches, where plant extracts containing reagents and catalysts are utilized in intensified chemical syntheses, creates expedient and sustainable processes. We illustrate this principle by reacting crude plant extract, oxygen, acid, and light to produce artemisinin, a key active pharmaceutical ingredient of the most powerful antimalarial drugs. The traditionally discarded extract of Artemisia annua plants contains dihydroartemisinic acid—the final biosynthetic precursor—as well as chlorophyll, which acts as a photosensitizer. Efficient irradiation with visible light in a continuous‐flow setup produces artemisinin in high yield, and the artificial biosynthetic process outperforms syntheses with pure reagents.
Pyrazole–Tetrazole Hybrid with Trinitromethyl, Fluorodinitromethyl, or (Difluoroamino)dinitromethyl Groups: High‐Performance Energetic Materials
Authors: Dalinger Igor L. , Kormanov Aleksandr V. , Suponitsky Kyrill Yu. , Muravyev Nikita V. , Sheremetev Aleksei B.
Published: February 2018

High‐nitrogen‐content compounds have attracted great scientific interest and technological importance because of their unique energy content, and they find diverse applications in many fields of science and technology. Understanding of structure–property relationship trends and how to modify them is of paramount importance for their further improvement. Herein, the installation of oxygen‐rich modules, C(NO2)3, C(NO2)2F, or C(NO2)2NF2, into an endothermic framework, that is, the combination of a nitropyrazole unit and tetrazole ring, is used as a way to design novel energetic compounds. Density, oxygen balance, and enthalpy of formation are enhanced by the presence of these oxygen‐containing units. The structures of all compounds were confirmed by XRD. For crystal packing analysis, it is proposed to use new criterion, ΔOED, that can serve as a measure of the tightness of molecular packing upon crystal formation. Overall, the materials show promising detonation and propulsion parameters.