bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic effects on life-history traits in the Glanville fritillary butterfly
Authors: Duplouy Anne , Wong Swee C. , Corander Jukka , Lehtonen Rainer , Hanski Ilkka
Published: May 2017

Background

Adaptation to local habitat conditions may lead to the natural divergence of populations in life-history traits such as body size, time of reproduction, mate signaling or dispersal capacity. Given enough time and strong enough selection pressures, populations may experience local genetic differentiation. The genetic basis of many life-history traits, and their evolution according to different environmental conditions remain however poorly understood.

Methods

We conducted an association study on the Glanville fritillary butterfly, using material from five populations along a latitudinal gradient within the Baltic Sea region, which show different degrees of habitat fragmentation. We investigated variation in 10 principal components, cofounding in total 21 life-history traits, according to two environmental types, and 33 genetic SNP markers from 15 candidate genes.

Results

We found that nine SNPs from five genes showed strong trend for trait associations (p-values under 0.001 before correction). These associations, yet non-significant after multiple test corrections, with a total number of 1,086 tests, were consistent across the study populations. Additionally, these nine genes also showed an allele frequency difference between the populations from the northern fragmented versus the southern continuous landscape.

Discussion

Our study provides further support for previously described trait associations within the Glanville fritillary butterfly species across different spatial scales. Although our results alone are inconclusive, they are concordant with previous studies that identified these associations to be related to climatic changes or habitat fragmentation within the Åland population.
NMR studies of the interaction between inner membrane‐associated and periplasmic cytochromes from Geobacter sulfurreducens
Authors: Dantas Joana M. , Brausemann Anton , Einsle Oliver , Salgueiro Carlos A.
Published: May 2017

Geobacter sulfurreducens is a dissimilatory metal‐reducing bacterium with notable properties and significance in biotechnological applications. Biochemical studies suggest that the inner membrane‐associated diheme cytochrome MacA and the periplasmic triheme cytochrome PpcA from G. sulfurreducens can exchange electrons. In this work, NMR chemical shift perturbation measurements were used to map the interface region and to measure the binding affinity between PpcA and MacA. The results show that MacA binds to PpcA in a cleft defined by hemes I and IV, favoring the contact between PpcA heme IV and the MacA high‐potential heme. The dissociation constant values indicate the formation of a low‐affinity complex between the proteins, which is consistent with the transient interaction observed in electron transfer complexes.
Cancer metastasis through the prism of epithelial‐to‐mesenchymal transition in circulating tumor cells
Authors: Micalizzi Douglas S. , Haber Daniel A. , Maheswaran Shyamala
Published: May 2017

Metastasis of epithelial cancer cells to distant sites is a particularly critical stage of cancer progression that typically marks the incurability of the disease. It is governed by a complex series of events including invasion and intravasation of tumor cells into the stroma and blood, respectively. Epithelial‐to‐mesenchymal transition (EMT), a phenotypic change marked by the loss of epithelial characteristics and the acquisition of invasive mesenchymal properties, is implicated in the dissemination of tumor cells. Circulating tumor cells (CTCs), the precursors of metastasis, can be used to interrogate the contribution of EMT in metastasis and therapeutic responses. The analysis of these CTCs and in particular the presence of inter‐ and intrapatient heterogeneity for markers of EMT has provided new insights into the metastatic process. This review will focus on epithelial–mesenchymal plasticity in CTCs and its potential clinical implications.
Diurnal variation of oxygen isotopic enrichment in asymmetric‐18 ozone observed by the SMILES from space
Authors: Sato T. O. , Kuribayashi K. , Yoshida N. , Kasai Y.
Published: May 2017

Atomic oxygen is a key oxidant for greenhouse gases such as H2O, CH4, and N2O whose amounts are currently increasing in the stratosphere. Ozone photolysis is a major source of atomic oxygen generation. We found, for the first time, that the ozone photolysis of 48O3 and 18O16O16O generated a sharp diurnal variation of δ18OOO in the middle stratosphere (37 km), in contrast to the temporal variation of 48O3. The average isotopic enrichment δ18OOO derived from the Superconducting Submillimeter‐Wave Limb‐Emission Sounder (SMILES) observation was higher during daytime (16.2 ± 3.3%) than at night (13.7 ± 3.6%). Isotopic fractionation effects were simulated for both ozone formation reaction and ozone photolysis with the ozone photolysis contribution estimated to be 80% of the daytime δ18OOO enhancement. Significant solar radiation dependence was observed in the isotopic fractionation of ozone photolysis derived from the SMILES observation and theoretical calculations. These results show that δ18O can be a powerful tool to investigate oxidant chemistry.
Observation and interpretation of energetic ion conics in Jupiter's polar magnetosphere
Authors: Clark G. , Mauk B. H. , Paranicas C. , Haggerty D. , Kollmann P. , Rymer A. , Brown L. , Jaskulek S. , Schlemm C. , Kim C. , Peachey J. , LaVallee D. , Allegrini F. , Bagenal F. , Bolton S. , Connerney J. , Ebert R. W. , Hospodarsky G. , Levin S. , Kurth W. S. , McComas D. J. , Mitchell D. G. , Ranquist D. , Valek P.
Published: May 2017

NASA's Juno spacecraft successfully completed its first science polar pass over Jupiter's northern and southern aurora, with all the instruments powered, on 27 August 2016. Observations of conical energetic proton distributions at low altitudes (<6 RJ) over the northern polar region are interpreted as resulting from transversely (to the local magnetic field lines) accelerated H+ at a position planetward of the point of observation. The proton conics were observed within a broad region of upward beaming electrons and were accompanied by broadband low‐frequency wave emissions as well as low‐altitude trapped magnetospheric protons and heavy ions. The characteristic energies associated with these accelerated ion conics are ~100 times more energetic than similar distributions observed in the Earth's auroral region and similar in energy to those found at Saturn. In addition, the ion conics also exhibited pitch angle dispersion with time that is interpreted as a consequence of the structure of the source location. Mapping these distributions along magnetic field lines connected from the spacecraft to the ionosphere suggests that the source region exists at altitudes between ~3 and 5 RJ. These new and exciting observations of accelerated ions over the polar region of Jupiter open up new areas for comparative planetary auroral physics.
The first close‐up images of Jupiter's polar regions: Results from the Juno mission JunoCam instrument
Authors: Orton Glenn S. , Hansen Candice , Caplinger Michael , Ravine Michael , Atreya Sushil , Ingersoll Andrew P. , Jensen Elsa , Momary Thomas , Lipkaman Leslie , Krysak Daniel , Zimdar Robert , Bolton Scott
Published: May 2017

During Juno's first perijove encounter, the JunoCam instrument acquired the first images of Jupiter's polar regions at 50–70 km spatial scale at low emission angles. Poleward of 64–68° planetocentric latitude, where Jupiter's east‐west banded structure breaks down, several types of discrete features appear on a darker background. Cyclonic oval features are clustered near both poles. Other oval‐shaped features are also present, ranging in size from 2000 km down to JunoCam's resolution limits. The largest and brightest features often have chaotic shapes. Two narrow linear features in the north, associated with an overlying haze feature, traverse tens of degrees of longitude. JunoCam also detected an optically thin cloud or haze layer past the northern nightside terminator estimated to be 58 ± 21 km (approximately three scale heights) above the main cloud deck. JunoCam will acquire polar images on every perijove, allowing us to track the state and evolution of longer‐lived features.
Multivariate Copula Analysis Toolbox (MvCAT): Describing dependence and underlying uncertainty using a Bayesian framework
Authors: Sadegh Mojtaba , Ragno Elisa , AghaKouchak Amir
Published: May 2017

We present a newly developed Multivariate Copula Analysis Toolbox (MvCAT) which includes a wide range of copula families with different levels of complexity. MvCAT employs a Bayesian framework with a residual‐based Gaussian likelihood function for inferring copula parameters and estimating the underlying uncertainties. The contribution of this paper is threefold: (a) providing a Bayesian framework to approximate the predictive uncertainties of fitted copulas, (b) introducing a hybrid‐evolution Markov Chain Monte Carlo (MCMC) approach designed for numerical estimation of the posterior distribution of copula parameters, and (c) enabling the community to explore a wide range of copulas and evaluate them relative to the fitting uncertainties. We show that the commonly used local optimization methods for copula parameter estimation often get trapped in local minima. The proposed method, however, addresses this limitation and improves describing the dependence structure. MvCAT also enables evaluation of uncertainties relative to the length of record, which is fundamental to a wide range of applications such as multivariate frequency analysis.
Radiation near Jupiter detected by Juno/JEDI during PJ1 and PJ3
Authors: Paranicas C. , Mauk B. H. , Haggerty D. K. , Clark G. , Kollmann P. , Rymer A. M. , Szalay J. R. , Ranquist D. , Bagenal F. , Levin S. M. , Connerney J. E. P. , Bolton S. J.
Published: May 2017

After its capture into Jupiter orbit early in the summer of 2016, the Juno spacecraft made three close flybys of the planet to date. The Jupiter Energetic Particle Detector Instrument (JEDI) made continuous measurements during perijoves in late August and early December. Here we describe the radiation (approximately hundreds of keV to more than 10 MeV charged particles) that was measured close to Jupiter. The purpose of this paper is to present some of the first direct energetic charged particle measurements ever obtained at high magnetic latitude very close to Jupiter and to interpret these data using techniques that rely on the instrument design. We generate an electron energy spectrum in an intense radiation region where the JEDI foreground is only about 40% of the rate due to >15 MeV electrons.
Preliminary JIRAM results from Juno polar observations: 2. Analysis of the Jupiter southern H3+ emissions and comparison with the north aurora
Authors: Adriani A. , Mura A. , Moriconi M. L. , Dinelli B. M. , Fabiano F. , Altieri F. , Sindoni G. , Bolton S. J. , Connerney J. E. P. , Atreya S. K. , Bagenal F. , Gérard J.‐C. M. C. , Filacchione G. , Tosi F. , Migliorini A. , Grassi D. , Piccioni G. , Noschese R. , Cicchetti A. , Gladstone G. R. , Hansen C. , Kurth W. S. , Levin S. M. , Mauk B. H. , McComas D. J. , Olivieri A. , Turrini D. , Stefani S. , Amoroso M.
Published: May 2017

The Jupiter InfraRed Auroral Mapper (JIRAM) aboard Juno observed the Jovian South Pole aurora during the first orbit of the mission. H3+ (trihydrogen cation) and CH4 (methane) emissions have been identified and measured. The observations have been carried out in nadir and slant viewing both by a L‐filtered imager and a 2–5 μm spectrometer. Results from the spectral analysis of the all observations taken over the South Pole by the instrument are reported. The coverage of the southern aurora during these measurements has been partial, but sufficient to determine different regions of temperature and abundance of the H3+ ion from its emission lines in the 3–4 μm wavelength range. Finally, the results from the southern aurora are also compared with those from the northern ones from the data taken during the same perijove pass and reported by Dinelli et al. (2017).
Infrared observations of Jovian aurora from Juno's first orbits: Main oval and satellite footprints
Authors: Mura A. , Adriani A. , Altieri F. , Connerney J. E. P. , Bolton S. J. , Moriconi M. L. , Gérard J.‐C. , Kurth W. S. , Dinelli B. M. , Fabiano F. , Tosi F. , Atreya S. K. , Bagenal F. , Gladstone G. R. , Hansen C. , Levin S. M. , Mauk B. H. , McComas D. J. , Sindoni G. , Filacchione G. , Migliorini A. , Grassi D. , Piccioni G. , Noschese R. , Cicchetti A. , Turrini D. , Stefani S. , Amoroso M. , Olivieri A.
Published: May 2017

The Jovian Infrared Auroral Mapper (JIRAM) is an imager/spectrometer on board NASA/Juno mission for the study of the Jovian aurorae. The first results of JIRAM's imager channel observations of the H3+ infrared emission, collected around the first Juno perijove, provide excellent spatial and temporal distribution of the Jovian aurorae, and show the morphology of the main ovals, the polar regions, and the footprints of Io, Europa and Ganymede. The extended Io “tail” persists for ~3 h after the passage of the satellite flux tube. Multi‐arc structures of varied spatial extent appear in both main auroral ovals. Inside the main ovals, intense, localized emissions are observed. In the southern aurora, an evident circular region of strong depletion of H3+ emissions is partially surrounded by an intense emission arc. The southern aurora is brighter than the north one in these observations. Similar, probably conjugate emission patterns are distinguishable in both polar regions.
Electron butterfly distributions at particular magnetic latitudes observed during Juno's perijove pass
Authors: Ma Q. , Thorne R. M. , Li W. , Zhang X.‐J. , Mauk B. H. , Paranicas C. , Haggerty D. K. , Kurth W. S. , Connerney J. E. P. , Bagenal F. , Bolton S. J.
Published: May 2017

We report observations of energetic electron butterfly distributions measured in a narrow range of Jupiter's magnetic latitudes by Juno during perijove 1. The electron butterfly distributions are characterized as clear electron flux peaks at 30–80° pitch angles, compared with the 90°‐peaked pitch angle distributions of the trapped electrons. Jupiter Energetic Particle Detector Instrument measurements during the close approach to Jupiter indicate a specific electron population with butterfly distributions formed between the main auroral oval and the radiation belt. The off‐90° flux peak is most clearly observed at tens of keV energies and gradually merges toward 90° pitch angle at higher energies. By projecting the observed electron pitch angle distributions along the magnetic field line, we found that the electron butterfly distributions are observed close to their source region. The particular electron distribution is possibly formed by parallel acceleration of electrons through Landau resonance with electrostatic waves.
Magnetosphere‐ionosphere coupling at Jupiter: Expectations for Juno Perijove 1 from a steady state axisymmetric physical model
Authors: Cowley S. W. H. , Provan G. , Bunce E. J. , Nichols J. D.
Published: May 2017

We evaluate the expected effects of magnetosphere‐ionosphere coupling at Jupiter along the Juno Perijove 1 (PJ1) trajectory using an axisymmetric physical model. As found at Saturn, the model predicts distributed downward field‐aligned currents over polar regions mapping to the tail and outer magnetosphere, closed principally through a ring of upward current mapping to the middle magnetosphere, which requires downward acceleration of magnetospheric electrons generating Jupiter's main auroral emission. Auroral location, width, intensity, electron energy, and current density are in accord with values derived from previous ultraviolet imaging, such that the model forms an appropriate baseline for comparison with Juno data. We evaluate the azimuthal field perturbations during six anticipated near‐planet encounters with middle magnetosphere field lines at radial distances between ~1.6 and ~16 Jovian radii, discuss the expected form of the accelerated electron distributions, and comment briefly on model expectations in relation to first results derived from Juno PJ1 data.
Jupiter gravity field estimated from the first two Juno orbits
Authors: Folkner W. M. , Iess L. , Anderson J. D. , Asmar S. W. , Buccino D. R. , Durante D. , Feldman M. , Gomez Casajus L. , Gregnanin M. , Milani A. , Parisi M. , Park R. S. , Serra D. , Tommei G. , Tortora P. , Zannoni M. , Bolton S. J. , Connerney J. E. P. , Levin S. M.
Published: May 2017

The combination of the Doppler data from the first two Juno science orbits provides an improved estimate of the gravity field of Jupiter, crucial for interior modeling of giant planets. The low‐degree spherical harmonic coefficients, especially J4 and J6, are determined with accuracies better than previously published by a factor of 5 or more. In addition, the independent estimates of the Jovian gravity field, obtained by the orbits separately, agree within uncertainties, pointing to a good stability of the solution. The degree 2 sectoral and tesseral coefficients, C2,1, S2,1, C2,2, and S2,2, were determined to be statistically zero as expected for a fluid planet in equilibrium.
Statistical study of latitudinal beaming of Jupiter's decametric radio emissions using Juno
Authors: Imai Masafumi , Kurth William S. , Hospodarsky George B. , Bolton Scott J. , Connerney John E. P. , Levin Steven M.
Published: May 2017

Synoptic decametric (DAM) radio observations at Jupiter were made in a broad Jovicentric latitudinal range of −21° to +15° by the Juno polar orbiting spacecraft from 21 June to 10 December 2016. We investigated the occurrence probability of non‐Io‐related DAM. At 19.5 MHz, as Juno's latitude varies from +15° to −21°, a peak of non‐Io‐B occurrence probability at 175° System III central meridian longitude (CML) gradually shifts in longitude to 140° CML. Also, another peak occurs at 110° CML between −15° and −9°, merging into the bottom edge of the former peak. This J‐shaped feature is similarly seen at 16.5 MHz. Using the Jovian magnetic field models, the fixed hollow cone model can reasonably account for the J‐shaped structure for radio sources traced along active magnetic flux tubes onto Jupiter's surface projected at about 135°–149° System III longitude. Moreover, these non‐Io‐B spectral profiles extend from 13.5 to 23.5 MHz.
Comparing Jupiter interior structure models to Juno gravity measurements and the role of a dilute core
Authors: Wahl S. M. , Hubbard W. B. , Militzer B. , Guillot T. , Miguel Y. , Movshovitz N. , Kaspi Y. , Helled R. , Reese D. , Galanti E. , Levin S. , Connerney J. E. , Bolton S. J.
Published: May 2017

The Juno spacecraft has measured Jupiter's low‐order, even gravitational moments, J2–J8, to an unprecedented precision, providing important constraints on the density profile and core mass of the planet. Here we report on a selection of interior models based on ab initio computer simulations of hydrogen‐helium mixtures. We demonstrate that a dilute core, expanded to a significant fraction of the planet's radius, is helpful in reconciling the calculated Jn with Juno's observations. Although model predictions are strongly affected by the chosen equation of state, the prediction of an enrichment of Z in the deep, metallic envelope over that in the shallow, molecular envelope holds. We estimate Jupiter's core to contain a 7–25 Earth mass of heavy elements. We discuss the current difficulties in reconciling measured Jn with the equations of state and with theory for formation and evolution of the planet.
An analytical model of maximum potential intensity for tropical cyclones incorporating the effect of ocean mixing
Authors: Miyamoto Yoshiaki , Bryan George H. , Rotunno Richard
Published: May 2017

An analytical model of maximum potential intensity (PI) for tropical cyclones (TCs) incorporating wind‐induced ocean cooling is developed on the basis of Emanuel's PI theory. The model consists of a one‐dimensional ocean and an axisymmetric TC vortex that is translating at a constant speed. The model advances upon previous approaches by accounting for TC size and shape. The PI is determined at the radius of maximum winds by radially integrating the effect of ocean mixing using a specified wind profile. The resulting analytic ocean cooling agrees well with numerical solutions, and the new PI model better captures maximum intensities of observed TCs compared with Emanuel's original PI. It is also shown that the degree of cooling (i.e., ocean's feedback to atmosphere) can be quantified by a dimensionless parameter, representing the ratio of atmospheric forcing to ocean stability.
A Bayesian hierarchical model for climate change detection and attribution
Authors: Katzfuss Matthias , Hammerling Dorit , Smith Richard L.
Published: May 2017

Regression‐based detection and attribution methods continue to take a central role in the study of climate change and its causes. Here we propose a novel Bayesian hierarchical approach to this problem, which allows us to address several open methodological questions. Specifically, we take into account the uncertainties in the true temperature change due to imperfect measurements, the uncertainty in the true climate signal under different forcing scenarios due to the availability of only a small number of climate model simulations, and the uncertainty associated with estimating the climate variability covariance matrix, including the truncation of the number of empirical orthogonal functions (EOFs) in this covariance matrix. We apply Bayesian model averaging to assign optimal probabilistic weights to different possible truncations and incorporate all uncertainties into the inference on the regression coefficients. We provide an efficient implementation of our method in a software package and illustrate its use with a realistic application.
Variability in seasonal forecast skill of Northern Hemisphere winters over the twentieth century
Authors: O'Reilly Christopher H. , Heatley James , MacLeod Dave , Weisheimer Antje , Palmer Tim N. , Schaller Nathalie , Woollings Tim
Published: May 2017

Seasonal hindcast experiments, using prescribed sea surface temperatures (SSTs), are analyzed for Northern Hemisphere winters from 1900 to 2010. Ensemble mean Pacific/North American index (PNA) skill varies dramatically, dropping toward zero during the mid‐twentieth century, with similar variability in North Atlantic Oscillation (NAO) hindcast skill. The PNA skill closely follows the correlation between the observed PNA index and tropical Pacific SST anomalies. During the mid‐century period the PNA and NAO hindcast errors are closely related. The drop in PNA predictability is due to mid‐century negative PNA events, which were not forced in a predictable manner by tropical Pacific SST anomalies. Overall, negative PNA events are less predictable and seem likely to arise more from internal atmospheric variability than positive PNA events. Our results suggest that seasonal forecasting systems assessed over the recent 30 year period may be less skillful in periods, such as the mid‐twentieth century, with relatively weak forcing from tropical Pacific SST anomalies.
The coastal mean dynamic topography in Norway observed by CryoSat‐2 and GOCE
Authors: Idžanović Martina , Ophaug Vegard , Andersen Ole Baltazar
Published: May 2017

New‐generation synthetic aperture radar altimetry, as implemented on CryoSat‐2, observes sea surface heights in coastal areas that were previously not monitored by conventional altimetry. Therefore, CryoSat‐2 is expected to improve the coastal mean dynamic topography (MDT). However, the MDT remains highly reliant on the geoid. Using new regional geoid models as well as CryoSat‐2 data, we determine three geodetic coastal MDT models in Norway and validate them against independent tide‐gauge observations and the operational coastal ocean model NorKyst800. The CryoSat‐2 MDTs agree on the ∼3–5 cm level with both tide‐gauge geodetic and ocean MDTs along the Norwegian coast. In addition, we compute geostrophic surface currents to help identifying errors in the geoid models. We find that even though the regional geoid models are all based on the latest satellite gravity data as provided by GOCE, the resulting circulation patterns differ. We demonstrate that some of these differences are due to erroneous or lack of marine gravity data. This suggests that there is significant MDT signal at spatial scales beyond GOCE, and that the geodetic approach to MDT determination benefits from the additional terrestrial gravity information provided by a regional geoid model. We also find that the border of the geographical mode mask of CryoSat‐2 coincides with the Norwegian Coastal Current, making it challenging to distinguish between artifacts in the CryoSat‐2 observations during mode switch and ocean signal.
Introduction and evaluation of a Weibull hydraulic conductivity‐pressure head relationship for unsaturated soils
Authors: Assouline Shmuel , Selker John
Published: May 2017

Analytical and numerical solutions for flow through partially saturated soils typically require functional relationships between water content, pressure, and hydraulic conductivity. Here we propose a Weibull‐type function to describe the hydraulic conductivity‐pressure head function. We show that this is a more flexible function that has the ability to address air entry pressure, while retaining the ease of integration and differentiation that facilitates many important computations which have to this point favored the Gardner exponential function (which is a special case of the proposed function). The ability to fit measured values is shown to be better than commonly employed functions of similar simplicity. Strong relationships were found between the parameters of the proposed function and the corresponding soil water retention curve, thus providing predictive capability. A simple relationship was also found between the parameters of the function and the wetting front pressure, ψf. Applying the proposed function to estimate ψf improves the accuracy of predictions for infiltration using the Green and Ampt model.
Phase and Composition Tuning of 1D Platinum‐Nickel Nanostructures for Highly Efficient Electrocatalysis
Authors: Jiang Kezhu , Shao Qi , Zhao Dandan , Bu Lingzheng , Guo Jun , Huang Xiaoqing
Published: May 2017

Among various platinum (Pt)‐based nanostructures, porous or hollow ones are of great importance because they exhibit fantastic oxygen reduction reaction (ORR) enhancements and maximize atomic utilization by exposing both exterior and interior surfaces. Here, a new class of porous Pt3Ni nanowires (NWs) with 1D architecture, an ultrathin Pt‐rich shell, high index facets, and a highly open structure is designed via a selective etching strategy by using the phase and composition segregated Pt‐Ni NWs as the starting material. The porous feature of Pt3Ni NWs can be readily fulfilled by changing the Pt/Ni atomic ratio of the starting Pt‐Ni NWs. Such porous Pt3Ni NWs show extraordinary activity and stability enhancements toward methanol oxidation reaction and ORR. The porous Pt3Ni NWs can deliver ORR mass activity of 5.60 A mg−1, which is 37.3‐fold higher than that of the Pt/C. They also show outstanding stability with negligible activity loss after 20 000 cycles. This study offers a unique approach for the design of complex nanostructures as efficient catalysts through precisely tailoring.
3D Bioprinting Human Induced Pluripotent Stem Cell Constructs for In Situ Cell Proliferation and Successive Multilineage Differentiation
Authors: Gu Qi , Tomaskovic‐Crook Eva , Wallace Gordon G. , Crook Jeremy M.
Published: May 2017

The ability to create 3D tissues from induced pluripotent stem cells (iPSCs) is poised to revolutionize stem cell research and regenerative medicine, including individualized, patient‐specific stem cell‐based treatments. There are, however, few examples of tissue engineering using iPSCs. Their culture and differentiation is predominantly planar for monolayer cell support or induction of self‐organizing embryoids (EBs) and organoids. Bioprinting iPSCs with advanced biomaterials promises to augment efforts to develop 3D tissues, ideally comprising direct‐write printing of cells for encapsulation, proliferation, and differentiation. Here, such a method, employing a clinically amenable polysaccharide‐based bioink, is described as the first example of bioprinting human iPSCs for in situ expansion and sequential differentiation. Specifically, we have extrusion printed the bioink including iPSCs, alginate (Al; 5% weight/volume [w/v]), carboxymethyl‐chitosan (5% w/v), and agarose (Ag; 1.5% w/v), crosslinked the bioink in calcium chloride for a stable and porous construct, proliferated the iPSCs within the construct and differentiated the same iPSCs into either EBs comprising cells of three germ lineages—endoderm, ectoderm, and mesoderm, or more homogeneous neural tissues containing functional migrating neurons and neuroglia. This defined, scalable, and versatile platform is envisaged being useful in iPSC research and translation for pharmaceuticals development and regenerative medicine.
Propulsion and Chemotaxis in Bacteria‐Driven Microswimmers
Authors: Zhuang Jiang , Park Byung‐Wook , Sitti Metin
Published: May 2017

Despite the large body of experimental work recently on biohybrid microsystems, few studies have focused on theoretical modeling of such systems, which is essential to understand their underlying functioning mechanisms and hence design them optimally for a given application task. Therefore, this study focuses on developing a mathematical model to describe the 3D motion and chemotaxis of a type of widely studied biohybrid microswimmer, where spherical microbeads are driven by multiple attached bacteria. The model is developed based on the biophysical observations of the experimental system and is validated by comparing the model simulation with experimental 3D swimming trajectories and other motility characteristics, including mean squared displacement, speed, diffusivity, and turn angle. The chemotaxis modeling results of the microswimmers also agree well with the experiments, where a collective chemotactic behavior among multiple bacteria is observed. The simulation result implies that such collective chemotaxis behavior is due to a synchronized signaling pathway across the bacteria attached to the same microswimmer. Furthermore, the dependencies of the motility and chemotaxis of the microswimmers on certain system parameters, such as the chemoattractant concentration gradient, swimmer body size, and number of attached bacteria, toward an optimized design of such biohybrid system are studied. The optimized microswimmers would be used in targeted cargo, e.g., drug, imaging agent, gene, and RNA, transport and delivery inside the stagnant or low‐velocity fluids of the human body as one of their potential biomedical applications.
Graphdiyne Filter for Decontaminating Lead‐Ion‐Polluted Water
Authors: Liu Rong , Zhou Jingyuan , Gao Xin , Li Jiaqiang , Xie Ziqian , Li Zhenzhu , Zhang Shuqing , Tong Lianming , Zhang Jin , Liu Zhongfan
Published: May 2017

The decontamination of water polluted with heavy metal ions is of worldwide concern. Among various treatment approaches to remove metal ions from water, adsorption is regarded as an efficient method, and a variety of materials have been applied as adsorbents for the removal of metal ions from polluted water. Recently, carbon nanomaterials have been examined as alternative adsorbents due to their high specific surface areas, high removal efficiency, and strong interactions with metal ions. Graphdiyne, a new kind of carbon allotrope composed of sp‐ and sp2‐hybridized carbon atoms, has attracted great interest due to its impressive properties. Graphdiyne is considered to be a promising candidate for the adsorption of heavy metal ions as the acetylenic links in graphdiyne strongly interact with metal ions. Herein, graphdiyne is used as an adsorbent to remove lead ions from water. The interaction between lead ions and graphdiyne is explored by X‐ray photoelectron spectroscopy and Raman spectroscopy. The maximum adsorption capacity calculated by the Langmuir isotherm model is 470.5 mg g−1. Graphdiyne is also synthesized on copper foam and used as a filter to eliminate lead ions from water. The filter shows high performance with a removal efficiency of 99.6% and can be recovered through treatment with acidic solution.
Temporal trends in craniometric estimates of admixture for a modern American sample
Authors: Algee‐Hewitt Bridget F. B.
Published: May 2017

Objectives

Temporal trends in craniometric estimates of admixture are investigated for three U.S. populations in the FDB. Patterns of association between birth years and posterior probabilities of cluster membership are identified to assess how these proportions of admixture have changed over recent time. Demographic and genetic data correlates, patterns of morphological expression, and shifts in source populations are evaluated.

Materials and Methods

Estimates of three‐way admixture were obtained for 1,521 individuals of documented population, sex, and birth years that span the 20th century. Correlations were calculated between birth years and admixture proportions for members of each FDB population. Population and sex‐specific admixture variation was further assessed by ANOVA and regression. Correlation analysis was used to identify, per population, which of the cranial measurements change in dimension under increased or decreased admixture.

Results

Admixture proportions differ significantly by population and change over time. No sex differences are detected. Analysis of the relationship between admixture proportions and ILDs finds that admixture drives morphological change in areas of the cranium known to vary among populations. Results agree with prior work on secular change.

Discussion

Findings reveal a progressive increase in White‐European population admixture for the self‐identified Black individuals, a recent demographic shift toward the increased representation of Hispanic individuals carrying greater Native American ancestry, and reduction in admixture for White individuals that suggest a loss of diversity over time. Changes in admixture produce tractable differences in morphological expression. Both sexes exhibit similar admixture proportions and self‐identification patterns. Observed diachronic trends are corroborated by information on recent U.S. demographic change.
Return to work after workplace injury: Injured workers, insurers and employers
Authors: Thornthwaite Louise , Markey Raymond
Published: May 2017

Returning injured workers to work is a central object of contemporary workers’ compensation systems. Injured workers’ interactions with insurers and employers are critical to achievement of timely and sustainable return to work outcomes. This article explores the interactions of injured workers with insurers and employers through analysis of their perceptions and experiences. The focus is on experiences with the NSW Workers Compensation scheme since 2012. To frame this analysis, the article proposes a model mapping these interactions, the relationships involved, the health, social and vocational consequences, and the return to work outcomes. The research found not only that the NSW Workers’ compensation system is failing to deliver a timely and durable return to work for many injured workers, but also that, for many, problematic and often pathogenic interactions with employers and insurers are resulting in exacerbated and secondary injuries and negative social and vocational consequences.
Cofactor‐Free, Direct Photoactivation of Enoate Reductases for the Asymmetric Reduction of C=C Bonds
Authors: Lee Sahng Ha , Choi Da Som , Pesic Milja , Lee Yang Woo , Paul Caroline E. , Hollmann Frank , Park Chan Beum
Published: May 2017

Enoate reductases from the family of old yellow enzymes (OYEs) can catalyze stereoselective trans‐hydrogenation of activated C=C bonds. Their application is limited by the necessity for a continuous supply of redox equivalents such as nicotinamide cofactors [NAD(P)H]. Visible light‐driven activation of OYEs through NAD(P)H‐free, direct transfer of photoexcited electrons from xanthene dyes to the prosthetic flavin moiety is reported. Spectroscopic and electrochemical analyses verified spontaneous association of rose bengal and its derivatives with OYEs. Illumination of a white light‐emitting‐diode triggered photoreduction of OYEs by xanthene dyes, which facilitated the enantioselective reduction of C=C bonds in the absence of NADH. The photoenzymatic conversion of 2‐methylcyclohexenone resulted in enantiopure (ee>99 %) (R)‐2‐methylcyclohexanone with conversion yields as high as 80–90 %. The turnover frequency was significantly affected by the substitution of halogen atoms in xanthene dyes.
Photoredoxkatalyse durch sensibilisierten Elektronentransfer
Authors: Ghosh Indrajit , Shaikh Rizwan S. , König Burkhard
Published: May 2017

Photosynthetische Organismen nutzen Antennenchromophore zur Lichtabsorption und übertragen die Anregungsenergie auf Reaktionszentren, in denen Redoxreaktionen ablaufen. Bei der chemischen Photokatalyse mit sichtbarem Licht wird dagegen nur ein einziges Molekül, der Photoredoxkatalysator, genutzt, um Licht zu absorbieren und die Redoxprozesse auszuführen. Wir berichten hier über eine Zwei‐Zentren‐Photoredoxkatalyse, bei der – in Analogie zum Energiefluss des biologischen Vorbilds – die Aufgaben der Lichtenergieabsorption und des Elektronentransfers auf zwei Moleküle verteilt werden: Ru(bpy)3Cl2 absorbiert sichtbares Licht und überträgt die Energie auf aromatische Kohlenwasserstoffe, an denen die Redoxreaktion abläuft. Dieser sensibilisierte Elektronentransfer ermöglicht die Nutzung von Aromaten, wie Anthracen oder Pyren, die selbst kein sichtbares Licht absorbieren, für die Photoredoxkatalyse. Die praktische Anwendung des Verfahrens zeigen wir anhand von Kohlenstoff‐Kohlenstoff‐ und Kohlenstoff‐Heteroatom‐Bindungsknüpfungen.
Molekulares Kästchenpapier
Authors: Lindner Marcin , Valášek Michal , Mayor Marcel , Frauhammer Timo , Wulfhekel Wulf , Gerhard Lukas
Published: May 2017

Hier wird eine selbstorganisierte molekulare Schablone vorgestellt, die aus Tetraphenylmethan‐basierten Derivaten besteht und auf einer Au(111)‐Oberfläche eine zweidimensional periodische Anordnung von Acetylgruppen aufweist, die aus dem molekularen Film hervorragen. Mithilfe der Spitze eines Rastertunnelmikroskops kann diese Acetylgruppe kontrolliert entfernt werden, ohne dass dabei die Anordnung des molekularen Films beeinflusst wird. Die chemisch modifizierten Moleküle sind leicht von den ursprünglichen Molekülen zu unterscheiden, sodass Informationen in den molekularen Film eingraviert werden können. Es konnte gezeigt werden, dass sowohl ein einzelnes modifiziertes Molekül als auch die Ordnung des Molekülfilms bei Raumtemperatur erhalten bleiben. Die Größe der Kästchen dieses molekularen Kästchenpapiers kann durch Variation der Länge des molekularen Abstandhalters vorgegeben werden, wodurch das Schreiben und das Lesen von Informationen auf der Nanoskala mit variabler Buchstabengröße möglich werden.
Cytoprotective Encapsulation of Individual Jurkat T Cells within Durable TiO2 Shells for T‐Cell Therapy
Authors: Youn Wongu , Ko Eun Hyea , Kim Mi‐Hee , Park Matthew , Hong Daewha , Seisenbaeva Gulaim A. , Kessler Vadim G. , Choi Insung S.
Published: May 2017

Lymphocytes, such as T cells and natural killer (NK) cells, have therapeutic promise in adoptive cell transfer (ACT) therapy, where the cells are activated and expanded in vitro and then infused into a patient. However, the in vitro preservation of labile lymphocytes during transfer, manipulation, and storage has been one of the bottlenecks in the development and commercialization of therapeutic lymphocytes. Herein, we suggest a cell‐in‐shell (or artificial spore) strategy to enhance the cell viability in the practical settings, while maintaining biological activities for therapeutic efficacy. A durable titanium oxide (TiO2) shell is formed on individual Jurkat T cells, and the CD3 and other antigens on cell surfaces remain accessible to the antibodies. Interleukin‐2 (IL‐2) secretion is also not hampered by the shell formation. This work suggests a chemical toolbox for effectively preserving lymphocytes in vitro and developing the lymphocyte‐based cancer immunotherapy.
Monofluoromethyl‐Substituted Sulfonium Ylides: Electrophilic Monofluoromethylating Reagents with Broad Substrate Scopes
Authors: Liu Yafei , Lu Long , Shen Qilong
Published: May 2017

Two electrophilic monofluoromethylating reagents, monofluoromethyl(phenyl)sulfonium bis(carbomethoxy)methylide (3 a) and monofluoromethyl(4‐nitrophenyl)sulfonium bis(carbomethoxy)methylide (3 b), and their reactions under mild conditions with a variety of nucleophiles, such as alcohols and malonate derivatives, sulfonic and carboxylic acids, phenols, amides, and N heteroarenes, are described. Mechanistic studies with deuterated reagents [D2]3 a/[D2]3 b suggest that these monofluoromethylation reactions proceed through an electrophilic substitution pathway.
Mechanism‐Based Enantiodivergence in Manganese Reduction Catalysis: A Chiral Pincer Complex for the Highly Enantioselective Hydroboration of Ketones
Authors: Vasilenko Vladislav , Blasius Clemens K. , Wadepohl Hubert , Gade Lutz H.
Published: May 2017

A manganese alkyl complex containing a chiral bis(oxazolinyl‐methylidene)isoindoline pincer ligand is a precatalyst for a catalytic system of unprecedented activity and selectivity in the enantioselective hydroboration of ketones, thus producing preparatively useful chiral alcohols in excellent yields with up to greater than 99 % ee. It is applicable for both aryl alkyl and dialkyl ketone reduction under mild reaction conditions (TOF >450 h−1 at −40 °C). The earth‐abundant base‐metal catalyst operates at very low catalyst loadings (as low as 0.1 mol %) and with a high level of functional‐group tolerance. There is evidence for the existence of two distinct mechanistic pathways for manganese‐catalyzed hydride transfer and their role for enantiocontrol in the selectivity‐determining step is presented.
Evidence of Structure Sensitivity in the Fischer–Tropsch Reaction on Model Cobalt Nanoparticles by Time‐Resolved Chemical Transient Kinetics
Authors: Ralston Walter T. , Melaet Gérôme , Saephan Tommy , Somorjai Gabor A.
Published: May 2017

The Fischer–Tropsch process, or the catalytic hydrogenation of carbon monoxide (CO), produces long chain hydrocarbons and offers an alternative to the use of crude oil for chemical feedstocks. The observed size dependence of cobalt (Co) catalysts for the Fischer–Tropsch reaction was studied with colloidally prepared Co nanoparticles and a chemical transient kinetics reactor capable of measurements under non‐steady‐state conditions. Co nanoparticles of 4.3 nm and 9.5 nm diameters were synthesized and tested under atmospheric pressure conditions and H2/CO=2. Large differences in carbon coverage (ΘC) were observed for the two catalysts: the 4.3 nm Co catalyst has a ΘC less than one while the 9.5 nm Co catalyst supports a ΘC greater than two. The monomer units present on the surface during reaction are identified as single carbon species for both sizes of Co nanoparticles, and the major CO dissociation site is identified as the B5‐B geometry. The difference in activity of Co nanoparticles was found to be a result of the structure sensitivity caused by the loss of these specific types of sites at smaller nanoparticle sizes.
Trapping a Silicon(I) Radical with Carbenes: A Cationic cAAC–Silicon(I) Radical and an NHC–Parent‐Silyliumylidene Cation
Authors: Li Yan , Chan Yuk‐Chi , Leong Bi‐Xiang , Li Yongxin , Richards Emma , Purushothaman Indu , De Susmita , Parameswaran Pattiyil , So Cheuk‐Wai
Published: May 2017

The trapping of a silicon(I) radical with N‐heterocyclic carbenes is described. The reaction of the cyclic (alkyl)(amino) carbene [cAACMe] (cAACMe=:C(CMe2)2(CH2)NAr, Ar=2,6‐iPr2C6H3) with H2SiI2 in a 3:1 molar ratio in DME afforded a mixture of the separated ion pair [(cAACMe)2Si:.]+I− (1), which features a cationic cAAC–silicon(I) radical, and [cAACMe−H]+I−. In addition, the reaction of the NHC–iodosilicon(I) dimer [IAr(I)Si:]2 (IAr=:C{N(Ar)CH}2) with 4 equiv of IMe (:C{N(Me)CMe}2), which proceeded through the formation of a silicon(I) radical intermediate, afforded [(IMe)2SiH]+I− (2) comprising the first NHC–parent‐silyliumylidene cation. Its further reaction with fluorobenzene afforded the CAr−H bond activation product [1‐F‐2‐IMe‐C6H4]+I− (3). The isolation of 2 and 3 confirmed the reaction mechanism for the formation of 1. Compounds 1–3 were analyzed by EPR and NMR spectroscopy, DFT calculations, and X‐ray crystallography.
Effect of pseudohalogen groups on the optical properties and the structures of diorganotin coordination compounds based on the flexible ligand 1,2,3,4‐tetra‐(4‐pyridyl)‐butane
Authors: Amini Mostafa M. , Najafi Ezzatollah , Saeidian Hamid , Mohammadi Elham , Shahabi Shiva Mosavi , Ng Seik Weng
Published: May 2017

To investigate the effect of pseudo‐halogen groups on the structure and optical properties of diorganotin(IV) coordination compounds the reaction of dimethyltin diisothiocyanate and dimethyltin dichloride with 1,2,3,4‐tetra‐ (4‐pyridyl)‐butane (TPB) were studied. The results of spectroscopic data and structural analyses of prepared compounds showed that the reaction of Me2SnCl2 with TPB ligand leads to the formation of a 2D organotin(IV) coordination polymer, while the replacement of chloride ions with thiocyanate ions as pseudohalogen groups in the structure of Me2SnCl2 results in the development of a salt with an anion complex and a dimeric stannoxane as a side product. The results showed that the use of pseudo‐halogen groups instead of halogen groups in the structure of diorganotin(IV) dihalogen compounds could be as a suitable factor in the control of the structure of diorganotin(IV) coordination compounds. The investigation of optical properties of prepared compounds demonstrated that the use of pseudo‐halogen groups in the structure of diorganotin(IV) coordination compounds have an influence on their photoluminescence behavior.
Effect of CO conversion upon product distribution using bimetallic Co‐Ni mesoporous silica catalyst for Fischer–Tropsch synthesis: a comparative study of fixed‐bed reactor and slurry continuous stirred tank reactor
Authors: Sun Yong , Yang Gang , Sun Zhi , Zhang Lian
Published: May 2017

Fischer–Tropsch synthesis was studied on mesoporous silica supported bimetallic Co‐Ni catalyst in the fixed‐bed reactor (FBR) and slurry continuous stirred tank reactor (CSTR) under different CO conversions by fixing other process parameters, for example, reaction temperature (300°C), syngas ratio (2), and total pressure (3 MPa). The CO conversion is more sensitive in responding to the decrease of gas hour space velocity in FBR than that in CSTR. The intra‐particle diffusional limitation was much improved in the CSTR system during Fischer–Tropsch synthesis due to the smaller particle size of the catalyst. The selectivity of gasoline fraction (C5–C13) was larger in CSTR than that in FBR when it was operated at relatively higher CO conversions (65%). The FBR tends to produce higher selectivity of longer‐chain hydrocarbons than that in CSTR when the CO conversion was kept at around 22%. The increased 1‐olefin selectivity was observed in both FBR and CSTR as CO conversion decrease with the FBR being more sensitive in responding to the CO conversion variation. The CSTR is found to be more effective in increasing light olefin fraction (C2–C6) when the CO conversion varies from 22 to 65%. © 2017 Curtin University of Technology and John Wiley & Sons, Ltd.