bluuebunny/crossref_metadata_2025 huggingface dataset:
Closing an early Miocene astronomical gap with Southern Ocean δ18O and δ13C records: Implications for sea level change
Authors: Miller Kenneth G. , Baluyot Ronidell , Wright James D. , Kopp Robert E. , Browning James V.
Published: May 2017

We present orbital‐scale resolution (~10 kyr) benthic foraminiferal δ18O and δ13C records from the Kerguelen Plateau (Ocean Drilling Program Sites 751 and 747) from 14.5 to 20.0 Ma spanning the Miocene climate optimum (15–17 Ma). Our records fill a critical gap from ~17 to 18 Ma, a time when many other deep‐sea records are affected by dissolution. We tested the fidelity of published magnetobiostratigraphic age models for these sites by astronomically tuning to the 405 kyr eccentricity cycle. A comparison of spectral estimates between the untuned and tuned records, as well as coherency with Laskar's (2004) eccentricity solution, revealed quasi‐100 kyr cyclicity in δ18O and δ13C. There is only a weak signal associated with the 41 kyr obliquity cycle, likely due to the 10 kyr sampling limiting resolution. The δ18O variations point to persistent 405 and quasi‐100 kyr modulations of temperature and sea level changes through the early to middle Miocene as predicted by astronomical solutions, with changing dominance of the 100 and 41 kyr beat. Comparison of δ18O records with early to middle Miocene sequences from the New Jersey shelf, northeast Australian margin, Bahamas, and Maldives suggests that the dominant sea level period preserved is the 1.2 Myr obliquity cycle, with sequence boundaries associated with δ18O increases or maxima. On the New Jersey margin, higher‐order sequences reflect the quasi‐100 kyr eccentricity cycles as modulated by 405 kyr cycles. We suggest that “nesting” of stratigraphic cycles is a function of the following: (1) pervasive (though changing) Milankovitch forcing of global mean sea level change and (2) preservation that depends on sufficient sediment supply and accommodation.
An evaporite‐bearing accretionary complex in the northern front of the Betic‐Rif orogen
Authors: Pérez‐Valera Fernando , Sánchez‐Gómez Mario , Pérez‐López Alberto , Pérez‐Valera Luis Alfonso
Published: May 2017

The Guadalquivir Accretionary Complex forms a largely oblique prism at the northern edge of the Betic‐Rif orogen, where Miocene sediments plus allochthonous evaporite‐bearing units were accreted during the displacement of the Alborán Domain toward the west. Traditional interpretations end the tectonic structuring of the Betic Cordillera at the present topographic front, beyond which gravitational and/or diapiric processes would predominate. However, this study shows pervasive tectonic deformation in the outer prism with coherent oblique shortening kinematics, which is achieved through an alternation of roughly N‐S arcuate thrust systems connected by E‐W transfer fault zones. These structures accord well with the geophysical models that propose westward rollback subduction. The main stage of tectonic activity occurred in the early‐middle Miocene, but deformation lasted until the Quaternary with the same kinematics. Evaporite rocks played a leading role in the deformation as evidenced by the suite of ductile structures in gypsum distributed throughout the area. S‐ and L‐ gypsum tectonites, scaly clay fabrics, and brittle fabrics coexist and consistently indicate westward motion (top to 290°), with subordinate N‐S contraction almost perpendicular to the transfer zones. This work reveals ductile tectonic fabrics in gypsum as a valuable tool to elucidate the structure and deformational history of complex tectonic mélanges involving evaporites above the décollement level of accretionary wedges.
Replenishing an unconfined coastal aquifer to control seawater intrusion: Injection or infiltration?
Authors: Lu Chunhui , Shi Wenlong , Xin Pei , Wu Jichun , Werner Adrian D.
Published: May 2017

In this study, we compare the performances of well injection and pond infiltration in controlling seawater intrusion in an unconfined coastal aquifer through two scenario groups: (1) a single injection well versus an elliptic infiltration pond and (2) an injection‐extraction well pair system versus an elliptic infiltration pond‐extraction well system. Comparison is based on quantitative indicators that include the interface toe location, saltwater volume, and maximum net extraction rate (for scenario 2). We introduce a method to determine the maximum net extraction rate for cases where the locations of stagnation points cannot be easily derived. Analytical analysis shows that the performances of injection and infiltration are the same, provided that the pond shape is circular. The examination of scenario group 1 suggests that the shape of the infiltration pond has a minor effect on the interface toe location as well as the reduction in the saltwater volume, given the same total recharge rate. The investigation of scenario group 2 indicates, by contrast, that the maximum net extraction rate increases significantly with the increasing ratio of b to a, where a and b are semiaxes of the ellipse parallel and perpendicular to the coastline, respectively. Specifically, for a typical aquifer assumed, an increase of 40% is obtained for the maximum net extraction when b/a increases from 1/200 to 200. Despite that the study is based on a simplified model, the results provide initial guidance for practitioners when planning to use an aquifer recharge strategy to restore a salinized unconfined coastal aquifer.
Concentration‐discharge relationships during an extreme event: Contrasting behavior of solutes and changes to chemical quality of dissolved organic material in the Boulder Creek Watershed during the September 2013 flood
Authors: Rue Garrett P. , Rock Nathan D. , Gabor Rachel S. , Pitlick John , Tfaily Malak , McKnight Diane M.
Published: May 2017

During the week of 9–15 September 2013, about 44 cm of rain fell across Boulder County, Colorado, USA, representing a very rare precipitation event. The resultant streamflows corresponded to an extreme event not seen since the historical flood of 1894. For the Boulder Creek Critical Zone Observatory (BcCZO), this event provided an opportunity to study the effect of extreme rainfall on solute concentration‐discharge relationships and biogeochemical processes. We measured weathering‐derived lithologic solutes (Ca, Mg, Na, K, and Si) and dissolved organic carbon (DOC) concentrations at two sites on Boulder Creek during the recession of peak flow. We also isolated four distinct fractions of dissolved organic matter (DOM) for chemical characterization. At the upper and lower sites, all solutes had their highest concentration at peak flow. At the upper site, which represented a mostly forested catchment, the concentrations of lithologic solutes decreased slightly during flood recession. In contrast, DOC and K concentrations decreased by a factor of three. At the lower site within the urban corridor, concentration of lithologic solutes decreased substantially for a few days before rebounding, whereas the DOC and K concentrations continued to decrease. Additionally, we found spatiotemporal trends in the chemical quality of DOM that were consistent with a limited reservoir of soluble organic matter in surficial soils becoming depleted and deeper layers of the Critical Zone contributing DOM during the flood recession. Overall, these results suggest that despite the extreme flood event, concentration‐discharge relationships were similar to typical snowmelt periods in this Rocky Mountain region.
Observations of the impact of rock heterogeneity on solute spreading and mixing
Authors: Boon Maartje , Bijeljic Branko , Krevor Samuel
Published: May 2017

Rock heterogeneity plays an important role in solute spreading and mixing in hydrogeologic systems. Few observations, however, have been made that can spatially resolve these processes in 3‐D, in consolidated rocks. We make observations of the spatially resolved steady state concentration of a sodium iodide solute while flowing brine through cylindrical rock cores using X‐ray CT imaging. Three rocks with an increasing level of heterogeneity are chosen: a Berea sandstone, a Ketton carbonate, and an Indiana carbonate. The impact of heterogeneity on solute transport is analyzed by: (1) quantifying spreading and mixing using metrics such as the transverse dispersion coefficient, the dilution index, the reactor ratio, and the scalar dissipation rate and (2) visualizing and analyzing flow structures such as meandering, flow‐focusing, and flow‐splitting using isoconcentration contour maps. The transverse dispersion coefficient, Dt, and the variation in Dt throughout the rock core, increases with Peclét number (Pe) and rock heterogeneity. The reactor ratio indicates that mixing is Fickian for the Berea sandstone and Ketton carbonate, but diverges for the Indiana carbonate. The temporal evolution of the scalar dissipation rate, a measure of the mixing rate, remains close to that of Fickian mixing for the Berea and Ketton rocks but not for the Indiana. Heterogeneous rock features are observed to cause meandering, focusing, or splitting of the plume depending on Pe.
Understanding the unique biogeochemistry of the Mediterranean Sea: Insights from a coupled phosphorus and nitrogen model
Authors: Powley Helen R. , Krom Michael D. , Van Cappellen Philippe
Published: May 2017

The Mediterranean Sea (MS) is an oligotrophic basin whose offshore water column exhibits low dissolved inorganic phosphorus (P) and nitrogen (N) concentrations, unusually high nitrate (NO3) to phosphate (PO4) ratios, and distinct biogeochemical differences between the Western Mediterranean Sea (WMS) and Eastern Mediterranean Sea (EMS). A new mass balance model of P and N cycling in the WMS is coupled to a pre‐existing EMS model to understand these biogeochemical features. Estimated land‐derived inputs of reactive P and N to the WMS and EMS are similar per unit surface area, but marine inputs are 4 to 5 times greater for the WMS, which helps explain the approximately 3 times higher primary productivity of the WMS. The lateral inputs of marine sourced inorganic and organic P support significant fractions of new production in the WMS and EMS, similar to subtropical gyres. The mass balance calculations imply that the MS is net heterotrophic: dissolved organic P and N entering the WMS and EMS, primarily via the Straits of Gibraltar and Sicily, are mineralized to PO4 and NO3 and subsequently exported out of the basin by the prevailing anti‐estuarine circulation. The high deepwater (DW) molar NO3:PO4 ratios reflect the high reactive N:P ratio of inputs to the WMS and EMS, combined with low denitrification rates. The lower DW NO3:PO4 ratio of the WMS (21) compared to the EMS (28) reflects lower reactive N:P ratios of inputs to the WMS, including the relatively low N:P ratio of Atlantic surface water flowing into the WMS.
Pervasive silicification and hanging wall overplating along the 13°20′N oceanic detachment fault (Mid‐Atlantic Ridge)
Authors: Bonnemains D. , Escartín J. , Mével C. , Andreani M. , Verlaguet A.
Published: May 2017

The corrugated detachment fault zone of the active 13°20′N oceanic core complex (Mid‐Atlantic Ridge) was investigated with a deep‐sea vehicle to assess the links between deformation, alteration, and magmatism at detachment fault zones. We present a study of 18 in situ fault rock samples from striated fault outcrops on the flanks of microbathymetric corrugations. All the samples are mafic breccias that are mostly derived from a diabase protolith, with two of them also showing mixing with ultramafic clasts. Breccias are cataclastic and display variable deformation textures, recording numerous slip events, and showing pervasive silicification throughout the fault zone. Deformation‐silicification relationships are also complex, showing both static and syntectonic quartz precipitation; undeformed quartz overprints the fault breccia textures, and reflective and striated fault surfaces cross‐cut silicified rocks. In situ detachment fault rocks are mainly fault breccias with almost exclusively basaltic clasts, with rare ultramafic ones, a lithology and texture never observed previously at other oceanic detachment fault zones. We propose the lower dyke complex in the hanging wall crust at the volcanic rift valley floor is the most plausible diabase source. Mechanical mixing of predominantly mafic and rare ultramafic clasts suggests an underlying ultramafic footwall and that mafic accretion operates in the shallowest crust (1–2 km), at the base of the dyke complex at temperatures >400°C. Silicification is produced by silica‐rich fluids syntectonically channeled along the fault zone, and likely derived from hydrothermal alteration of basaltic rocks, likely mixed with serpentinization‐derived fluids.
An Argo mixed layer climatology and database
Authors: Holte James , Talley Lynne D. , Gilson John , Roemmich Dean
Published: May 2017

A global climatology and database of mixed layer properties are computed from nearly 1,250,000 Argo profiles. The climatology is calculated with both a hybrid algorithm for detecting the mixed layer depth (MLD) and a standard threshold method. The climatology provides accurate information about the depth, properties, extent, and seasonal patterns of global mixed layers. The individual profile results in the database can be used to construct time series of mixed layer properties in specific regions of interest. The climatology and database are available online at http://mixedlayer.ucsd.edu. The MLDs calculated by the hybrid algorithm are shallower and generally more accurate than those of the threshold method, particularly in regions of deep winter mixed layers; the new climatology differs the most from existing mixed layer climatologies in these regions. Examples are presented from the Labrador and Irminger Seas, the Southern Ocean, and the North Atlantic Ocean near the Gulf Stream. In these regions the threshold method tends to overestimate winter MLDs by approximately 10% compared to the algorithm.
Convective aggregation in realistic convective‐scale simulations
Authors: Holloway Christopher E.
Published: May 2017

To investigate the real‐world relevance of idealized‐model convective self‐aggregation, five 15 day cases of real organized convection in the tropics are simulated. These include multiple simulations of each case to test sensitivities of the convective organization and mean states to interactive radiation, interactive surface fluxes, and evaporation of rain. These simulations are compared to self‐aggregation seen in the same model configured to run in idealized radiative‐convective equilibrium. Analysis of the budget of the spatial variance of column‐integrated frozen moist static energy shows that control runs have significant positive contributions to organization from radiation and negative contributions from surface fluxes and transport, similar to idealized runs once they become aggregated. Despite identical lateral boundary conditions for all experiments in each case, systematic differences in mean column water vapor (CWV), CWV distribution shape, and CWV autocorrelation length scale are found between the different sensitivity runs, particularly for those without interactive radiation, showing that there are at least some similarities in sensitivities to these feedbacks in both idealized and realistic simulations (although the organization of precipitation shows less sensitivity to interactive radiation). The magnitudes and signs of these systematic differences are consistent with a rough equilibrium between (1) equalization due to advection from the lateral boundaries and (2) disaggregation due to the absence of interactive radiation, implying disaggregation rates comparable to those in idealized runs with aggregated initial conditions and noninteractive radiation. This points to a plausible similarity in the way that radiation feedbacks maintain aggregated convection in both idealized simulations and the real world.
High‐Speed Roll‐to‐Roll Hot Embossing of Micrometer and Sub Micrometer Structures Using Seamless Direct Laser Interference Patterning Treated Sleeves
Authors: Rank Andreas , Lang Valentin , Lasagni Andrés Fabián
Published: May 2017

In this study, we present a seamless high‐speed roll‐to‐roll hot embossing process using a direct laser interference patterned nickel sleeve as a mold. Line‐like patterns with spatial periods of 5.0, 3.9, and 1.5 μm and structure heights of 572, 325, and 141 nm, respectively are used for imprinting PET‐foils. The influence of the web speed on the cavity filling and consequently on the structure height and homogeneity of the fabricated patterns is studied. The web speed is varied between 2 and 50 m min−1. For the 5.0 and 3.9 μm periods, a decrease in structure height with the web speed occurs, while for the 1.5 μm period the structure height remains constant in the tested interval. Also a decrease in homogeneity is observed with increasing web speed. Finally, an analytical model, based on the Navier–Stokes equation and Hertzian contact pressure, is used to explain the experimental results. The experimental data are in good agreement with the calculated theoretical values.
Single CdS Nanorod for High Responsivity UV–Visible Photodetector
Authors: Zhao Wu , Liu Lin , Xu Manzhang , Wang Xuewen , Zhang Ting , Wang Yingnan , Zhang Zhiyong , Qin Sujie , Liu Zheng
Published: May 2017

1D nanoscale photodetectors have been extensively investigated for the unique geometry structure and novel physical and chemical properties. The 1D CdS materials have received much attention in the field due to its high photosensitivity and fast response, while how to achieve high responsivity is still in development, despite it is the crucial target to the excellent photodetector. Single crystal CdS nanorods (NRs) are synthesized on SiO2/Si substrate over large scale via the chemical vapor deposition method. The individual single CdS nanorod photodetector have been fabricated by using photolithography process and the responsivity of the photodetector is investigated systematically. At a very low percentage of illumination intensity (2%, 0.5 mW cm−2) under 450 nm, the photodetector exhibited a high responsivity and reached at 1.23 × 104 A W−1 with the bias voltages of 2 V. The good crystallinity and large surface of CdS nanorod are the reasons of this excellent performance of CdS based photodetector. The strategy proposed herein appears to hold great potential for a high responsivity with low illumination intensity.
Design of the printing pattern on film for three‐dimensional molded interconnect devices
Authors: Liu Ren Hao , Young Wen‐Bin , Ming Hsu Pe
Published: May 2017

This article discusses the application of an in‐mold decoration (IMD) technology for the development of three‐dimensional molded interconnect devices (3D‐MID). The 3D‐MID process uses the film printing technology to print the circuit pattern on a plastic film, and then deform it to the shape of the component by thermoforming. Then, the plastic film is placed inside the mold cavity for injection molding, and is attached to the surface of the component after molding. Experiments were performed for the 3D‐MID process using a semisphere shape. A simple geometric model was also proposed to correlate the printed film patterns before and after the thermoforming. The geometric model will be used to design the required printing pattern on a 2D film for a given 3D pattern on a component.
Copper‐Catalyzed Regioselective Formal Allylboration of Aryl‐Substituted Terminal Alkynes with Bis(pinacolato)diboron and Allyl Halides/Sulfonates
Authors: Jing Haitong , Feng Xiaorui , Guo Minjie , Zhou Sen , Li Yanlin , Zhang Jiacheng , Zhao Wentao , Tang Xiangyang , Wang Guangwei
Published: May 2017

A copper‐catalyzed formal allylboration of terminal alkynes using allyl bromides or sulfonates as electrophiles has been achieved. This method exhibits good regio‐/stereoselectivity and good functional‐group tolerance for various substituents on the aromatic rings of arylethynes. Through this strategy, various trisubstituted vinyl pinacol boronic esters with a 1,4‐diene skeleton have been constructed. In order to demonstrate the utility of this method, the resulting 1,4‐dienes with boron substitution were further used in transformations such as Suzuki coupling, oxidation, halogenation, and so on, leading to various important compounds.
Umkehr der Polarität: α‐Aminierungen von Carbonylverbindungen mit Stickstoffnukleophilen
Authors: de la Torre Aurélien , Tona Veronica , Maulide Nuno
Published: May 2017

Die Synthese von α‐Aminocarbonylverbindungen ist eine wichtige Herausforderung in der Synthese biologisch essenzieller Strukturen. Da bei den klassischen Ansätzen Enole oder Enolate in Verbindung mit einer elektrophilen Stickstoffquelle verwendet werden, ist bei diesen Methoden normalerweise eine weitere Umwandlung erforderlich, um die gewünschten Zielverbindungen zu realisieren. In den letzten Jahren wurde ein neuer Ansatz entwickelt, bei dem nukleophile Stickstoffquellen zusammen mit einem Oxidans direkt eingesetzt werden. Dieser Ansatz hat den Vorteil, dass er in einer Eintopfreaktion zur biologisch relevanten α‐Aminoverbindung führt, ohne dass eine weitere Umwandlung notwendig wäre. In diesem Kurzaufsatz werden die jüngsten Fortschritte in dem aufstrebenden Gebiet der oxidativen α‐Aminierungsreaktionen unter Verwendung von nukleophilen Stickstoffquellen dargelegt.
Self‐Assembled Zinc/Cystine‐Based Chloroplast Mimics Capable of Photoenzymatic Reactions for Sustainable Fuel Synthesis
Authors: Liu Kai , Yuan Chengqian , Zou Qianli , Xie Zengchun , Yan Xuehai
Published: May 2017

Prototypes of biosystems provide good blueprints for the design and creation of biomimetic systems. However, mimicking both the sophisticated natural structures and their complex biological functions still remains a great challenge. Herein, chloroplast mimics have been fabricated by one‐step bioinspired amino acid mineralization and simultaneous integration of catalytically active units. Hierarchically structured crystals were obtained by the metal‐ion‐directed self‐assembly of cystine (the oxidized dimer of the amino acid cysteine), with a porous structure and stacks of nanorods, which show similar architectural principles to chloroplasts. Porphyrins and enzymes can both be encapsulated inside the crystal during mineralization, rendering the crystal photocatalytically and enzymatically active for an efficient and sustainable synthesis of hydrogen and acetaldehyde in a coupled photoenzymatic reaction.
Selected Copper‐Based Reactions for C−N, C−O, C−S, and C−C Bond Formation
Authors: Bhunia Subhajit , Pawar Govind Goroba , Kumar S. Vijay , Jiang Yongwen , Ma Dawei
Published: May 2017

Metal‐catalyzed cross‐coupling reactions belong to the most important transformations in organic synthesis. Copper catalysis has received great attention owing to the low toxicity and low cost of copper. However, traditional Ullmann‐type couplings suffer from limited substrate scopes and harsh reaction conditions. The introduction of several bidentate ligands, such as amino acids, diamines, 1,3‐diketones, and oxalic diamides, over the past two decades has totally changed this situation as these ligands enable the copper‐catalyzed coupling of aryl halides and nucleophiles at both low reaction temperatures and catalyst loadings. The reaction scope has also been greatly expanded, rendering this copper‐based cross‐coupling attractive for both academia and industry. In this Review, we have summarized the latest progress in the development of useful reaction conditions for the coupling of (hetero)aryl halides with different nucleophiles. Additionally, recent advances in copper‐catalyzed coupling reactions with aryl boronates and the copper‐based trifluoromethylation of aromatic electrophiles will be discussed.
Influence of electrolytes of Li salts, EMIMBF4, and mixed phases on electrochemical and physical properties of Nafion membrane
Authors: Safari Maryam , Naji Leila , Baker Richard T. , Afshar Taromi Faramarz
Published: May 2017

Electrolyte‐soaked Nafion is commonly used as an ionic polymer in soft actuators. Here, a multitechnique investigation was applied to correlate the electrochemical behavior of Nafion membranes with their microstructures and nanostructures as a function of electrolyte type. The influence of electrolytes of Li salts with different counteranions on the Nafion membranes was investigated in terms of hydration level, structure (using X‐ray diffraction and small angle X‐ray scattering), stress–strain characteristics, and electrochemical behavior (by cyclic voltammetery and electrochemical impedance spectroscopy). The effects of using ionic liquid (IL), as the electrolyte, addition of different supporting solvent and the addition of Li+ ions to water‐free IL‐soaked membranes on the structural and electrochemical properties of Nafion were examined. The nano‐ and microstructure of the Nafion changed considerably as a function of the identity of the electrolyte solution. The electrochemical behavior of the IL‐soaked samples was compared with that of the water‐soaked Li+‐exchanged Nafion. It was seen that the ionic conductivity of the Nafion membranes was reduced significantly when water was replaced by pure IL. Using the supporting solvents increased the conductivity of IL‐soaked Nafion membranes dramatically. The presence of a small amount of Li+ ions together with the IL ions caused a significant decrease in charge transfer resistance and increases in double layer capacitance and in ionic conductivity over that of the water‐free sample and also over water‐soaked Li+‐exchanged Nafion. These findings can be useful to improve the knowledge on Nafion's microstructure and also to improve the electromechanical behavior of Nafion‐based ionic polymer–metal composites actuators. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45239.
Understanding the Mechanisms of Gold Shell Growth onto Polymer Microcapsules to Control Shell Thickness
Authors: Tasker Alison L. , Hitchcock James , Baxter Elaine A. , Cayre Dr Olivier J. , Biggs Simon
Published: May 2017

Polymer microcapsules have been used commercially for decades, however they have an inherent flaw which renders them impractical as a carrier of small, volatile molecules. The porous nature of the polymer shell allows for diffusion of the encapsulated molecules into the bulk. The use of metal shells is an innovative way to prevent undesired loss of small molecules from the core of microcapsules, however it is important, particularly when using expensive metals to ensure that the resulting shell is as thin as possible. Here we investigate the fundamental mechanisms controlling the gold shell thickness when a fragrance oil is encapsulated in a poly(methyl methacrylate) shell. We consider the distribution of the nanoparticles on the capsule surface, and from quantification of the adsorbed nanoparticle (NP) density and resulting shell thickness, we propose mechanisms to describe the gold shell growth for systems with high and low NP surface coverage. We suggest from our observations that the gold grows to fill in the gaps between NPs. At low NP concentrations, thicker metal shells form. We postulate that this is due to the low NP density on the surface, forcing the gold clusters to grow larger before they meet the adjacent ones. Thus, to grow the thinnest possible shells a densely packed monolayer of platinum nanoparticles is required on the capsule surface.
Reading and listening progress in segregated primary schools: Does ethnic and socioeconomic classroom composition matter?
Authors: Dewulf Lisa , van Braak Johan , Van Houtte Mieke
Published: May 2017

This study aimed to investigate the relationship of classroom composition factors with reading and listening comprehension achievement and progress in socially and ethnically segregated primary schools in Flanders (Belgium). Specifically, using a three‐level multivariate repeated measures analysis, it examined the association of reading and listening achievement and progress with ethnic diversity, the proportion of non‐native students and the average socioeconomic status of the class, taking into account student characteristics. At the beginning and end of the school year, reading tests, listening tests and questionnaires were administered to a sample of 7‐ and 8‐year‐old students (n = 683) in 42 second‐grade classes. Students' listening comprehension achievement at the beginning of the school year was negatively related to having a home language other than the language of instruction and to classes with a high proportion of non‐native students. However, progress in listening comprehension was not significantly associated with any student or classroom composition factors. Students whose mothers had a lower level of education performed lower on reading comprehension at the beginning of the school year, while at the end of the school year students whose mothers had a higher level of education were at a greater disadvantage. Limitations of this study and directions for future research are discussed.
A pump‐free microfluidic 3D perfusion platform for the efficient differentiation of human hepatocyte‐like cells
Authors: Ong Louis Jun Ye , Chong Lor Huai , Jin Lin , Singh Pawan Kumar , Lee Poh Seng , Yu Hanry , Ananthanarayanan Abhishek , Leo Hwa Liang , Toh Yi‐Chin
Published: May 2017

The practical application of microfluidic liver models for in vitro drug testing is partly hampered by their reliance on human primary hepatocytes, which are limited in number and have batch‐to‐batch variation. Human stem cell‐derived hepatocytes offer an attractive alternative cell source, although their 3D differentiation and maturation in a microfluidic platform have not yet been demonstrated. We develop a pump‐free microfluidic 3D perfusion platform to achieve long‐term and efficient differentiation of human liver progenitor cells into hepatocyte‐like cells (HLCs). The device contains a micropillar array to immobilize cells three‐dimensionally in a central cell culture compartment flanked by two side perfusion channels. Constant pump‐free medium perfusion is accomplished by controlling the differential heights of horizontally orientated inlet and outlet media reservoirs. Computational fluid dynamic simulation is used to estimate the hydrostatic pressure heads required to achieve different perfusion flow rates, which are experimentally validated by micro‐particle image velocimetry, as well as viability and functional assessments in a primary rat hepatocyte model. We perform on‐chip differentiation of HepaRG, a human bipotent progenitor cell, and discover that 3D microperfusion greatly enhances the hepatocyte differentiation efficiency over static 2D and 3D cultures. However, HepaRG progenitor cells are highly sensitive to the time‐point at which microperfusion is applied. Isolated HepaRG cells that are primed as static 3D spheroids before being subjected to microperfusion yield a significantly higher proportion of HLCs (92%) than direct microperfusion of isolated HepaRG cells (62%). This platform potentially offers a simple and efficient means to develop highly functional microfluidic liver models incorporating human stem cell‐derived HLCs. Biotechnol. Bioeng. 2017;114: 2360–2370. © 2017 Wiley Periodicals, Inc.
Modeling thrombus formation and growth
Authors: Hosseinzadegan Hamid , Tafti Danesh K.
Published: May 2017

The paper reviews the state‐of‐the‐art in computational modeling of thrombus formation and growth and related phenomena including platelet margination, activation, adhesion, and embolization. Presently, there is a high degree of empiricism in the modeling of thrombus formation. Based on the experimentally observed physics, the review gives useful strategies for predicting thrombus formation and growth. These include determining blood components involved in atherosclerosis, effective blood viscosity, tissue properties, and methods proposed for boundary conditions. In addition to the guidelines, ongoing research on the effect of shear stress on platelet margination, activation and adhesion, and platelet‐surface interactions are reviewed. Biotechnol. Bioeng. 2017;114: 2154–2172. © 2017 Wiley Periodicals, Inc.
Neglected issues concerning teaching human adrenal steroidogenesis in popular biochemistry textbooks
Authors: Han Zhiyong , Elliott Mark S
Published: May 2017

In the human body, the adrenal steroids collectively regulate a plethora of fundamental functions, including electrolyte and water balance, blood pressure, stress response, intermediary metabolism, inflammation, and immunity. Therefore, adrenal steroidogenesis is an important biochemistry topic for students to learn in order for them to understand health consequences caused by deficiencies of enzymes in the adrenal steroidogenic pathways. However, popular biochemistry textbooks contain insufficient information and may sometimes give students a misimpression about certain aspects of human adrenal steroidogenesis. This article highlights two neglected issues in teaching human adrenal steroidogenesis in popular biochemistry textbooks. The purpose of this article is to draw attention to these issues. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(6):469–474, 2017.
Hydrophilic interaction and reversed‐phase ultra‐performance liquid chromatography TOF‐MS for metabolomic analysis of Veratrum nigrum‐induced cardiotoxicity
Authors: Wei Ziheng , Dong Xu , Zhang Hanzhe , Gao Songyan , Shi Wei , Yang Feng , Dong Xin
Published: May 2017

The acute cardiotoxicity induced by Veratrum nigrum (VN) is explored by analyzing heart tissue metabolic profiles in mouse models and applying reversed‐phase liquid chromatography mass spectrometry and hydrophilic interaction liquid chromatography mass spectrometry that are based on ultra‐high‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry. An animal model of acute heart injury was established in mice via intra‐gastric administration of VN. Then, electrocardiogram and echocardiograph monitoring of cardiac function and pathological examination were performed on mice in both the control and VN groups, and it was verified that acute heart injury was caused. Meanwhile, comparing the results of the control and VN groups, we detected 36 differential endogenous metabolites of heart tissue, including taurine, riboflavin, purine and lipids, which are related to many possible pathways such as purine metabolism, taurine and hypotaurine metabolism and energy metabolism. Our study provides a scientific approach for evaluating and revealing the mechanisms of VN‐induced cardiotoxicity via the metabolomic strategy.
Topologically consistent leafy tree morphing
Authors: Wang Yutong , Wang Luyuan , Deng Zhigang , Jin Xiaogang
Published: May 2017

We present a novel morphing technique to generate pleasing visual effects between 2 topologically varying trees while preserving the topological consistency and botanical meanings of any in‐between shapes as natural trees. Specifically, we first efficiently convert leafy trees into botanically inspired chain‐lobe representations in an automatic way. With the aid of branching‐pattern aware, one‐to‐many correspondences between branches and leaves, we hierarchically interpolate branches of in‐between trees while maintaining their topological consistencies. Finally, we simultaneously interpolate foliage, specifically every single leaf, during the morphing process, avoiding the generation of unpleasant “floating” leaves. We demonstrate the effectiveness of our approach by creating visually compelling tree morphing animations, even between cross‐species.
Simulating collective transport of virtual ants
Authors: Guo Shihui , Wang Meili , Notman Gabriel , Chang Jian , Zhang Jianjun , Liao Minghong
Published: May 2017

This paper simulates the behaviour of collective transport where a group of ants transports an object in a cooperative fashion. Different from humans, the task coordination of collective transport, with ants, is not achieved by direct communication between group individuals, but through indirect information transmission via mechanical movements of the object. This paper proposes a stochastic probability model to model the decision‐making procedure of group individuals and trains a neural network via reinforcement learning to represent the force policy. Our method is scalable to different numbers of individuals and is adaptable to users' input, including transport trajectory, object shape, external intervention, etc. Our method can reproduce the characteristic strategies of ants, such as realign and reposition. The simulations show that with the strategy of reposition, the ants can avoid deadlock scenarios during the task of collective transport.
A method for maintaining vascular access when Impella exchange is required
Authors: Cook B. Scott , Wilson Cleve , Kaiser Brooke , Baljepally Raj
Published: May 2017

A 45‐year old male with no prior cardiac history, presented with cardiogenic shock in the setting of an anterolateral ST elevation myocardial infarction. We first placed a 2.5 Impella for hemodynamic support, and proceeded with emergent percutaneous coronary intervention to the proximal LAD. Several hours following percutaneous coronary intervention (PCI), the patient became acutely hypotensive and an echocardiogram revealed the Impella catheter was kinked within the left ventricle. The patient was taken back to the cath lab for Impella adjustment; however, damage to the distal catheter required the Impella be exchanged. As the patient was therapeutically anticoagulated and on dual antiplatelet therapy, we modified the Impella catheter in order to maintain existing vascular access during Impella exchange. This case demonstrates our method for maintaining vascular access during Impella exchange, thereby eliminating the need for a second arterial puncture. © 2017 Wiley Periodicals, Inc.
Biventricular Impella placement via complete venous access
Authors: Kamioka Norihiko , Patel Ateet , Burke Michael A. , Greenbaum Adam , Babaliaros Vasilis
Published: May 2017

Impella (Abiomed, Danvers, MA) is an effective option for emergent treatment of critical refractory cardiogenic shock. However, in patients who have inadequate peripheral arterial access, Impella for left ventricular support sometimes requires surgical access, leading to disadvantages for emergent procedures or invasiveness for very sick patients. In addition, Impella for right ventricular support was recently reported to contribute to the management of severe biventricular dysfunction. In this report, we describe a case of refractory cardiogenic shock in a patient with inadequate vascular access who was treated with biventricular Impella via venous and caval‐aortic access under conscious sedation. This technique can be used as a bridge to surgical ventricular assist device or heart transplantation. © 2017 Wiley Periodicals, Inc.
Transcatheter edge‐to‐edge repair of anterior mitral flail through a dehisced annuloplasty ring
Authors: Ho Edwin C. , Ahmed Naveed , Connelly Kim A. , Fam Neil P.
Published: May 2017

Recurrent mitral regurgitation (MR) due to mitral annuloplasty ring dehiscence is an uncommon late complication of surgery, and is associated with an increased risk of heart failure and mortality. We report the first application of MitraClip for recurrent primary MR and annuloplasty ring dehiscence in a patient with prohibitive surgical risk.
Chest closure after rib‐cross thoracotomy for descending and thoracoabdominal aortic aneurysm repair
Authors: Uehara Kyokun , Matsuda Hitoshi , Minatoya Kenji , Kobayashi Junjiro
Published: May 2017

Key Clinical Message

The fixation system consisting of a titanium plate and three pairs of claws can fix the ribs externally. This may contribute to preserve the normal thoracic structure and could result in a significant reduction in the period of ventilator dependency.
Gold Doping in PtCu3/HSAC Nanoparticles and Their Morphological, Structural, and Compositional Changes during Oxygen Reduction Reaction Electrochemical Cycling
Authors: Ruiz‐Zepeda Francisco , Gatalo Matija , Jovanovič Primož , Pavlišič Andraž , Bele Marjan , Hodnik Nejc , Gaberšček Miran
Published: May 2017

Pt‐based nanoparticles supported on high‐surface‐area carbon (HSAC) show very good properties as catalysts in polymer electrolyte membrane fuel cells (PEMFC). In many cases, however, the initial high activity of such catalysts rapidly drops as caused by various detrimental phenomena occurring in a typical electrochemical environment. In this work, a detailed study of a highly active system composed of PtCu3/HSAC nanoparticles with partially ordered structure and Pt skin with the addition of Au is performed. By using aberration‐corrected scanning transmission electron microscopy, the effects of adding small amounts of gold compared to the nonmodified sample are followed through the different stages of an electrochemical cycling degradation protocol. Various morphological changes such as faceting, reshaping, and thickening of the Pt skin are investigated for both sets of samples on the atomic level. Interesting features such as well‐defined shapes and surface defects are observed after degradation. However, the most important differences in terms of durability seem related to particle porosity. Finally, the experimental morphological observations are successfully reproduced by dealloying simulation with kinetic Monte Carlo modeling.
Nickel‐Iron Alloy Nanoparticle‐Decorated K2NiF4‐Type Oxide as an Efficient and Sulfur‐Tolerant Anode for Solid Oxide Fuel Cells
Authors: Wu Nuo , Wang Wei , Zhong Yijun , Yang Guangming , Qu Jifa , Shao Zongping
Published: May 2017

We report a new nickel‐iron alloy nanoparticle‐decorated LaSrFe0.75Ni0.25O4 K2NiF4‐type oxide with Ruddlesden‐Popper structure (RP‐LSFN), which performed as a high‐performance sulfur‐resistant anode prepared by using an infiltration method for solid oxide fuel cells (SOFCs) with LaSrFeNiO6‐δ double perovskite (DP‐LSFN) as the precursor. A reduction converts the DP‐LSFN phase into mixed phases containing the RP‐LSFN and FeNi3 nanoparticles. The morphology, thermal expansion behavior, sulfur tolerance, and electrochemical activity for hydrogen oxidation of this FeNi3 nanoparticle‐decorated, RP‐LSFN‐infiltrated anode are investigated. An electrolyte‐supported SOFC with this infiltrated anode generates a high power output of 541 mW cm−2 at 800 °C operated with 1000 ppm H2S−H2 as the fuel, which compares favorably to that with pure H2 fuel. A single cell with this anode demonstrates favorable stability at 800 °C during 90, 40, and 20 h operation with H2 containing 100, 200, and 1000 ppm H2S, respectively.
AcetylacetonateBODIPY‐Biscyclometalated Iridium(III) Complexes: Effective Strategy towards Smarter Fluorescent Photosensitizer Agents
Authors: Palao Eduardo , Sola‐Llano Rebeca , Tabero Andrea , Manzano Hegoi , Agarrabeitia Antonia R. , Villanueva Angeles , López‐Arbeloa Iñigo , Martínez‐Martínez Virginia , Ortiz Maria J.
Published: May 2017

Biscyclometalated IrIII complexes involving boron‐dipyrromethene (BODIPY)‐based ancillary ligands, where the BODIPY unit is grafted to different chelating cores (acetylacetonate for Ir‐1 and Ir‐2, and bipyridine for Ir‐3) by the BODIPY meso position, have been synthesized and characterized. Complexes with the BODIPY moiety directly grafted to acetylacetonate (Ir‐1 and Ir‐2) exhibit higher absorption coefficients (ϵ≈4.46×104 m−1 cm−1 and 3.38×104 m−1 cm−1 at 517 nm and 594 nm, respectively), higher moderate fluorescence emission (φfl≈0.08 and 0.22 at 528 nm and 652 nm, respectively) and, in particular, more efficient singlet oxygen generation upon visible‐light irradiation (φΔ≈0.86 and 0.59, respectively) than that exhibited by Ir‐3 (φΔ≈0.51, but only under UV light). Phosphorescence emission, nanosecond time‐resolved transient absorption, and DFT calculations suggest that BODIPY‐localized long‐lived 3IL states are populated for Ir‐1 and Ir‐2. In vitro photodynamic therapy (PDT) activity studied for Ir‐1 and Ir‐2 in HeLa cells shows that such complexes are efficiently internalized into the cells, exhibiting low dark‐ and high photocytoxicity, even at significantly low complex concentration, making them potentially suitable as theranostic agents.
Universal Method for Large‐Scale Synthesis of Layered Transition Metal Dichalcogenides
Authors: Sofer Zdeněk , Sedmidubský David , Luxa Jan , Bouša Daniel , Huber Štěpán , Lazar Petr , Veselý Martin , Pumera Martin
Published: May 2017

The layered transition metal dichalcogenides are currently amongst the most intensively investigated materials. These compounds constitute a broad family of materials, with characteristic layered structures, covering both semiconductors and metallic materials. The great attention arises from the possibility to exfoliate these materials down to single layers with many unique properties, such as thickness dependent band‐gap energy, and the possibility of tuning transport properties by phase transitions. The research in the field of transition metal dichalcogenides is also motivated by their high electrocatalytic activity towards several industrially important reactions, such as the hydrogen evolution reaction, as well as many other applications in nano‐ and optoelectronics. Although these materials are studied intensively, their availability is extremely limited and only disulfides of molybdenum and tungsten are broadly commercially available. Here an optimized procedure for simple direct synthesis of transition metal dichalcogenides using powder metals and elemental chalcogens is reported. The optimized thermal treatment allowed the synthesis scaling of the sulfides, selenides and tellurides of 4th, 5th, 6th, and 7th group of layered‐structure dichalcogenides. The synthesized transition metal dichalcogenides were single phase. The phase purity, structure, and morphology were investigated in detail by electron microscopy and EDS, X‐ray diffraction, and Raman spectroscopy.
Immune and molecular correlates in melanoma treated with immune checkpoint blockade
Authors: Byrne Elizabeth H. , Fisher David E.
Published: May 2017

Immunotherapy for metastatic melanoma has a decades‐long history, and the relatively recent use of checkpoint inhibitors has revolutionized treatment. Durable and sometimes complete remission of metastatic melanoma is now achievable in some patients who receive checkpoint‐blocking therapy. However, it is unclear why some patients fare better than others. This review highlights several molecular indicators of response to checkpoint inhibition in metastatic melanoma, focusing on tumor programmed death ligand 1 expression, major histocompatibility complex class I expression, mutational load in the tumor, and T‐cell infiltration into the tumor. In addition, clinical correlates of response, notably vitiligo and other immune‐related adverse events, can potentially shed light on the mechanisms by which checkpoint blockade may achieve such great success, particularly in melanoma. The authors propose that microphthalmia‐associated transcription factor—a key regulator of melanocyte survival, melanin production, and melanoma transformation—produces a molecular landscape in melanocytes and melanoma cells that can make melanomas particularly susceptible to checkpoint blockade and also can result in immune attack on normal melanocytes. Cancer 2017;123:2143‐53. © 2017 American Cancer Society.