bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensory Differences and Mealtime Behavior in Children With Autism
Authors: Zobel-Lachiusa Jeanne , Andrianopoulos Mary V. , Mailloux Zoe , Cermak Sharon A.
Published: September 2015

This study examined sensory differences and mealtime behaviors in children with autism spectrum disorder (ASD; n = 34) and compared the results with those of similarly aged peers who were typically developing (TD; n = 34). Results from parent-report and child-report questionnaires indicated that children with ASD scored significantly differently from TD peers on the measures of sensory differences and eating behaviors. Data also supported a correlation between sensory differences and eating difficulties in children with ASD. The results of this study will help caregivers and their children with ASD identify problem eating behaviors that may be associated with sensory differences. Sensory strategies and techniques offered by occupational therapy practitioners may contribute to greater success during mealtimes for children with ASD and their families, with increased comfort and less stress. The findings also support a need to further explore the influence of sensory differences on mealtime behaviors.
Light absorption and morphological properties of soot-containing aerosols observed at an East Asian outflow site, Noto Peninsula, Japan
Authors: Ueda S. , Nakayama T. , Taketani F. , Adachi K. , Matsuki A. , Iwamoto Y. , Sadanaga Y. , Matsumi Y.
Published: September 2015

Abstract. The coating of black carbon (BC) with inorganic salts and organic compounds can enhance the magnitude of light absorption by BC. To elucidate the enhancement of light absorption of aged BC particles and its relation to the mixing state and morphology of individual particles, we conducted observations of particles at an Asian outflow site in Noto Peninsula, Japan, in the spring of 2013. Absorption and scattering coefficients at 405, 532, and 781 nm and mass concentrations/mixing states of refractory-BC in PM2.5 were measured using a three-wavelength photoacoustic soot spectrometer and a single-particle soot photometer (SP2), respectively, after passage through a heater maintained at 300 or 400 °C or a bypass line maintained at room temperature (25 °C). The average enhancement of BC light absorption due to coating was estimated by comparing absorption coefficients at 781 nm for particles that with and without passing through the heater and was found to be 22–23 %. The largest enhancements (> 30 %) were observed under high absorption coefficient conditions when the air mass was long-range transported from urban areas in China. Aerosol samples were also analyzed using a transmission electron microscope (TEM) equipped with an energy dispersive X-ray analyzer. The morphological features and mixing states of soot-containing particles of four samples collected during the high absorption coefficient events were analyzed by comparing microphotographs before and after the evaporation of beam-sensitive materials by irradiation with a high density electron beam. The majority of the soot in all samples was found as mixed particles with spherical sulfate or as clusters of sulfate spherules. For samples showing high enhancement (> 30 %) of BC light absorption, TEM showed that the internally mixed soot-containing particles tended to have a more spherical shape and to be embedded into the sulfate. The SP2 measurements also suggested that the proportion of thickly-coated soot was greater. Thus, the observed enhancement of BC light absorption was found to differ according to the mixing states and morphology of soot-containing particles. The enhancement of BC light absorption in our in situ measurements and its relation with individual features of soot-containing particles will be useful to evaluate direct radiative forcing in the leeward areas of large emission sources of BC.
Measurement of atomic oxygen in the middle atmosphere using solid electrolyte sensors and catalytic probes
Authors: Eberhart M. , Löhle S. , Steinbeck A. , Binder T. , Fasoulas S.
Published: September 2015

Abstract. The middle- and upper-atmospheric energy budget is largely dominated by reactions involving atomic oxygen (O). Modeling of these processes requires detailed knowledge about the distribution of this oxygen species. Understanding the mutual contributions of atomic oxygen and wave motions to the atmospheric heating is the main goal of the rocket project WADIS (WAve propagation and DISsipation in the middle atmosphere). It includes, amongst others, our instruments for the measurement of atomic oxygen that have both been developed with the aim of resolving density variations on small vertical scales along the trajectory. In this paper the instrument based on catalytic effects (PHLUX: Pyrometric Heat Flux Experiment) is introduced briefly. The experiment employing solid electrolyte sensors (FIPEX: Flux φ(Phi) Probe Experiment) is presented in detail. These sensors were laboratory calibrated using a microwave plasma as a source of atomic oxygen in combination with mass spectrometer reference measurements. The spectrometer was in turn calibrated for O with a method based on methane. In order to get insight into the horizontal variability, the rocket payload had instrument decks at both ends. Each housed several sensor heads measuring during both the up- and downleg of the trajectory. The WADIS project comprises two rocket flights during different geophysical conditions. Results from WADIS-1 are presented, which was successfully launched in June 2013 from the Andøya Space Center, Norway. FIPEX data were sampled at 100 Hz and yield atomic oxygen density profiles with a vertical resolution better than 9 m. This allows density variations to be studied on very small spatial scales. Numerical simulations of the flow field around the rocket were done at several points of the trajectory to assess the influence of aerodynamic effects on the measurement results. Density profiles peak at 3 × 1010 cm−3 at altitudes of 93.6 and 96 km for the up- and downleg, respectively.
Multi-century lake area changes in the Southern Altiplano: a tree-ring-based reconstruction
Authors: Morales M. S. , Carilla J. , Grau H. R. , Villalba R.
Published: September 2015

Abstract. Size fluctuations in endorheic lakes in northwestern Argentina (NWA) and southwestern Bolivia (SWB) are very sensitive to basin hydrological balances, and consequently, very vulnerable to deleterious effects from climatic changes. The management of these water resources and their biodiversity requires a comprehensive knowledge of their natural variability over multiple timescales. In this study, we present a multi-century reconstruction of past lake-area fluctuations in NWA and SWB. The evidence used to develop and validate this reconstruction includes satellite images and a century-long tree-ring record from P. tarapacana. Inter-annual fluctuations in lake area of nine lakes were quantified based on Landsat satellite images over the period 1975 to 2009. A regional P. tarapacana tree-ring chronology, composite from two sampling sites, was used as predictors in a regression model to reconstruct the mean annual (January–December) lake area from the nine lakes. The reconstruction model captures 62 % of the total variance in lake-area fluctuations and shows adequate levels of cross-validation. This high-resolution reconstruction covers the past 601 years and characterizes the occurrence of annual to multi-decadal lake area fluctuations and its main oscillation modes of variability. Our reconstruction points out that the late 20th century decrease in lake area was exceptional over the period 1407–2007; a persistent negative trend in lake area is clear in the reconstruction and consistent with glacier retreat and other climate proxies from the Altiplano and the tropical Andes. Since the mid 1970s, the Vilama-Coruto lake system recorded an accelerated decrease in area consistent with an increasing recurrence of extremely small lake-area events. Throughout the 601 years, the reconstruction provides valuable information about spatial and temporal stabilities of the relationships between changes in lake area, ENSO, and PDO, highlighting the Pacific influence over most modes of lake area variability. Global and regional climate models for the Altiplano project a marked reduction in precipitation to the end of the 21st century, exacerbating presently dry conditions. These results provide a baseline for the historical range of variability in lake fluctuations and thus should be considered for the management of biodiversity and water resources in the Central Andes during the next decades.
Evaluation of the Community Multiscale Air Quality (CMAQ) model v5.0 against size-resolved measurements of inorganic particle composition across sites in North America
Authors: Nolte C. G. , Appel K. W. , Kelly J. T. , Bhave P. V. , Fahey K. M. , Collett J. L. , Zhang L. , Young J. O.
Published: September 2015

Abstract. This work evaluates particle size–composition distributions simulated by the Community Multiscale Air Quality (CMAQ) model using micro-orifice uniform deposit impactor (MOUDI) measurements at 18 sites across North America. Size-resolved measurements of particulate SO42−, NO3−, NH4+, Na+, Cl−, Mg2+, Ca2+, and K+ are compared to CMAQ model output for discrete sampling periods between 2002 and 2005. The observation sites were predominantly in remote areas (e.g., National Parks) in the USA and Canada, and measurements were typically made for a period of roughly 1 month. For SO42− and NH4+, model performance was consistent across the USA and Canadian sites, with the model slightly overestimating the peak particle diameter and underestimating the peak particle concentration compared to the observations. Na+ and Mg2+ size distributions were generally well represented at coastal sites, indicating reasonable simulation of emissions from sea spray. CMAQ is able to simulate the displacement of Cl− in aged sea spray aerosol, though the extent of Cl− depletion relative to Na+ is often underpredicted. The model performance for NO3− exhibited much more site-to-site variability than that of SO42− and NH4+, with the model ranging from an underestimation to overestimation of both the peak diameter and peak particle concentration across the sites. Computing PM2.5 from the modeled size distribution parameters rather than by summing the masses in the Aitken and accumulation modes resulted in differences in daily averages of up to 1 μg m−3 (10 %), while the difference in seasonal and annual model performance compared to observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE), Chemical Speciation Network (CSN), and Air Quality System (AQS) networks was very small. Two updates to the CMAQ aerosol model – changes to the assumed size and mode width of emitted particles and the implementation of gravitational settling – resulted in small improvements in modeled size distributions.
Performance evaluation of groundwater model hydrostratigraphy from airborne electromagnetic data and lithological borehole logs
Authors: Marker P. A. , Foged N. , He X. , Christiansen A. V. , Refsgaard J. C. , Auken E. , Bauer-Gottwein P.
Published: September 2015

Abstract. Large-scale hydrological models are important decision support tools in water resources management. The largest source of uncertainty in such models is the hydrostratigraphic model. Geometry and configuration of hydrogeological units are often poorly determined from hydrogeological data alone. Due to sparse sampling in space, lithological borehole logs may overlook structures that are important for groundwater flow at larger scales. Good spatial coverage along with high spatial resolution makes airborne electromagnetic (AEM) data valuable for the structural input to large-scale groundwater models. We present a novel method to automatically integrate large AEM data sets and lithological information into large-scale hydrological models. Clay-fraction maps are produced by translating geophysical resistivity into clay-fraction values using lithological borehole information. Voxel models of electrical resistivity and clay fraction are classified into hydrostratigraphic zones using k-means clustering. Hydraulic conductivity values of the zones are estimated by hydrological calibration using hydraulic head and stream discharge observations. The method is applied to a Danish case study. Benchmarking hydrological performance by comparison of performance statistics from comparable hydrological models, the cluster model performed competitively. Calibrations of 11 hydrostratigraphic cluster models with 1–11 hydraulic conductivity zones showed improved hydrological performance with an increasing number of clusters. Beyond the 5-cluster model hydrological performance did not improve. Due to reproducibility and possibility of method standardization and automation, we believe that hydrostratigraphic model generation with the proposed method has important prospects for groundwater models used in water resources management.
Assessment of a critical area for a give-way ship in a collision encounter
Authors: Krata Przemysław , Montewka Jakub
Published: September 2015

Evasive action in ship-ship encounter has to be carried out on time and in line with the international convention on collision regulation – COLREG. The convention not only includes a set of rules defining types of relations between encountering ships but also indicates appropriate action to be taken in a given encounter. One of such encounters is crossing, where, in case of a collision situation, a give-way ship has to take an appropriate action in due time. However, a stand-on vessel is also given an opportunity to manoeuver, if it is made clear to her that the other ship is not fulfilling her obligations. However, it is difficult to specify, at which point in time in the course of an encounter, the stand-on ship has to take an action in order to avoid collision. It is understandable, as this parameter depends on numerous factors, both endogenous (e.g. ship characteristics, her maneuverability), and exogenous (e.g. type of encounter, weather conditions). Therefore in this paper we make an attempt towards the definition of the critical area for a maneuver of a stand-on ship, in the situation where the give-way vessel does not take an action. This is determined with the use of a hydrodynamic model of ship motion, and series of simulations conducted for several types of encountering ships under various conditions. Once determined, the critical area demarcates the no-go area around the own ship, where any other ships on collision courses must not enter. Otherwise a collision cannot be avoided by an action of one ship alone.
Generation of Self-Renewing Hepatoblasts From Human Embryonic Stem Cells by Chemical Approaches
Authors: Zhang Muzi , Sun Pingxin , Wang Yusheng , Chen Junnan , Lv Linjie , Wei Wanguo , Jin Caixia , Li Wenlin
Published: September 2015

Somatic stem cells play crucial roles in organogenesis and tissue homeostasis and regeneration and may ultimately prove useful for cell therapy for a variety of degenerative diseases and injuries; however, isolation and expansion of most types of somatic stem cells from tissues are technically challenging. Human pluripotent stem cells are a renewable source for any adult cell types, including somatic stem cells. Generation of somatic stem cells from human pluripotent stem cells is a promising strategy to get these therapeutically valuable cells. Previously, we developed a chemically defined condition for mouse hepatoblast self-renewal through a reiterative screening strategy. In the present study, we efficiently generated hepatoblasts from human embryonic stem cells by a stepwise induction strategy. Importantly, these human embryonic stem cell-derived hepatoblasts can be captured and stably maintained using conditions previously established for mouse hepatoblast self-renewal, which includes basal media supplemented with insulin, transferrin, sodium selenite, epidermal growth factor, glycogen synthase kinase 3 inhibitor, transforming growth factor β receptor inhibitor, lysophosphatidic acid, and sphingosine 1-phosphate. The cells can stably retain hepatoblast phenotypes during prolonged culture and can differentiate into mature hepatocytes through in vitro provision of hepatocyte lineage developmental cues. After being embedded into three-dimensional Matrigel, these cells efficiently formed bile duct-like structures resembling native bile duct tissues. These human embryonic stem cell-derived hepatoblasts would be useful as a renewable source for cell therapy of liver diseases.

Significance

Somatic stem cells have been proposed as promising candidates for cell-based therapy; however, isolation of somatic stem cells from adult tissues is usually invasive and technically challenging. In the present study, hepatoblasts from human embryonic stem cells were efficiently generated. These human hepatoblasts were then stably captured and maintained by a growth factor and small molecule cocktail, which included epidermal growth factor, glycogen synthase kinase 3 inhibitor, transforming growth factor β receptor inhibitor, lysophosphatidic acid, and sphingosine 1-phosphate. These human embryonic stem cell-derived hepatoblasts would be useful as a renewable source for cell therapy of liver diseases.
Effect of Surface Modification on the Absorption and Luminescence Response in tris(8-Hydroxyquinoline) Gallium Films Achieved by Thermal Treatment
Authors: Muhammad Fahmi Fariq
Published: September 2015

This work reports on the impact of surface modification on the optical absorption and luminescence response of vacuum deposited tris(8-hydroxyquinoline) gallium (Gaq3) films. This surface modification was achieved by means of thermal treatment under nitrogen gas in the temperature range from 85 oC to 255 oC. The results of field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD) technique ascertained the formation of amorphous nano-rods along the surface of Gaq3 films. Considerable improvement in the absorption and luminescence characteristics of Gaq3 films was observed upon surface modification, which has been resulted from this treatment process.
Carbon Nanotubes (CNTs) for Prolonging the Life of Micropunch
Authors: Guo Kelvii Wei , Tam Hon Yuen
Published: September 2015

Carbon nanotubes (CNTs) coated on the WC/Co micropunch with diameter in 150 μm for prolonging the life of micropunch was investigated. Carbon nanotubes were synthesized by homemade method. With scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the morphology and structure of CNTs had been expressed. After the punching test with Ti as substrate, the effect of CNTs for prolonging the life of micropunch on the wear loss and the surface morphology of micropunch had been studied by confocal laser, SEM, digital balance etc. Results show the wear of CNTs coated micropunch decreases obviously. Even in the severe wear period the wear loss is less than that of non-CNTs coated micropunch. Compared with the micropunch without CNTs coating, the promising results are due to the formation of a transfer film at the contact region by rubbing of the CNT forest, CNTs produced adheres to the micropunch surface avoiding direct contact during the punching period and providing lubricant properties to the interface by virtue of their graphitic nature. Also, the relevant mechanism was illustrated primarily.
Establishing the role of ATP for the function of the RIG-I innate immune sensor
Authors: Rawling David C , Fitzgerald Megan E , Pyle Anna Marie
Published: September 2015

Retinoic acid-inducible gene I (RIG-I) initiates a rapid innate immune response upon detection and binding to viral ribonucleic acid (RNA). This signal activation occurs only when pathogenic RNA is identified, despite the ability of RIG-I to bind endogenous RNA while surveying the cytoplasm. Here we show that ATP binding and hydrolysis by RIG-I play a key role in the identification of viral targets and the activation of signaling. Using biochemical and cell-based assays together with mutagenesis, we show that ATP binding, and not hydrolysis, is required for RIG-I signaling on viral RNA. However, we show that ATP hydrolysis does provide an important function by recycling RIG-I and promoting its dissociation from non-pathogenic RNA. This activity provides a valuable proof-reading mechanism that enhances specificity and prevents an antiviral response upon encounter with host RNA molecules.
The molecular mechanism of nuclear transport revealed by atomic-scale measurements
Authors: Hough Loren E , Dutta Kaushik , Sparks Samuel , Temel Deniz B , Kamal Alia , Tetenbaum-Novatt Jaclyn , Rout Michael P , Cowburn David
Published: September 2015

Nuclear pore complexes (NPCs) form a selective filter that allows the rapid passage of transport factors (TFs) and their cargoes across the nuclear envelope, while blocking the passage of other macromolecules. Intrinsically disordered proteins (IDPs) containing phenylalanyl-glycyl (FG)-rich repeats line the pore and interact with TFs. However, the reason that transport can be both fast and specific remains undetermined, through lack of atomic-scale information on the behavior of FGs and their interaction with TFs. We used nuclear magnetic resonance spectroscopy to address these issues. We show that FG repeats are highly dynamic IDPs, stabilized by the cellular environment. Fast transport of TFs is supported because the rapid motion of FG motifs allows them to exchange on and off TFs extremely quickly through transient interactions. Because TFs uniquely carry multiple pockets for FG repeats, only they can form the many frequent interactions needed for specific passage between FG repeats to cross the NPC.
La Comprensión Referencial Temprana: Aprendiendo Palabras a Través de Imágenes con Distinto Nivel de Iconicismo
Authors: Peralta Olga , Mareovich Florencia
Published: September 2015

El desarrollo de la comprensión referencial de imágenes transita un largo camino durante los primeros años de vida. Esta investigación tuvo como objetivo explorar el impacto del iconicismo en la comprensión referencial de imágenes impresas y el aprendizaje de palabras. En 2 estudios se enseñó a una muestra por conveniencia de 34 niños de 30 meses de edad de jardines infantiles de Rosario, Argentina, una palabra nueva aplicada a un objeto desconocido, mediante un libro de imágenes. Se comparó la ejecución infantil en 2 condiciones, fotografías y bocetos, variando el nivel de iconicismo o grado en que la imagen se asemeja al referente. La Prueba Exacta de Fisher reveló que aprendiendo con bocetos la palabra quedaba fuertemente asociada a la imagen, obstaculizando ver el objeto a través de ella, lo que no se observó en los niños que aprendieron la palabra mediante fotografías. Los resultados muestran que la similitud perceptual incide en la comprensión referencial, siendo las imágenes icónicas representaciones más transparentes a edades tempranas. Estos resultados pueden tener implicancias en el diseño de libros educativos para niños pequeños.
Antenna Arrays
Authors: Mailloux Robert J.
Published: September 2015

Consisting of two to thousands of antenna elements, an array antenna presents the ultimate in flexible pattern control. This capability includes electronic scanning, planar or conformable apertures, ability to transmit or receive multiple shaped patterns, and adaptive control for jammers, clutter, multipath suppression, and the reduction of co‐site interference. Arrays benefit from technological advances, and they are key technology drivers for solid‐state
T
/
R
(transmit/receive) modules, advanced signal processing, and photonic technology. This article overviews antenna arrays, subarrays and their architecture, phase control devices, and pattern analysis. Array mutual couplings, array synthesis, and theoretical and practical aspects of periodic, aperiodic, and conformal arrays are also presented.
Mechanical Accelerometers
Authors: Barone Fabrizio , Giordano Gerardo
Published: September 2015

Modern mechanical accelerometers are the result of more than a century of research and development aimed at optimizing the mechanical architectures of classical oscillators (simple pendulum, inverted pendulum, and spring–mass oscillator) as well as careful and effective applications of technology improvements and the introduction of innovative techniques of control and signal readout.

A further strong impulse to the development of mechanical accelerometers came from interferometric detectors of gravitational waves, which require accelerometers able to satisfy very stringent specifications on sensitivity, bandwidth, resonance frequency, directivity, compactness, and weight, for applications both in air and in ultrahigh vacuum (UHV) and cryogenics.

Among the different mechanical architectures present in literature, the Watt's linkage is one of the most promising ones for the implementation of a new class of mechanical accelerometers (horizontal, vertical, and angular).

In this article, a simplified analytical model for a global description of the mechanical behavior and of the sensitivity limits of Watt's linkage‐based mechanical accelerometers is presented and discussed, with respect to methods and techniques for their optimization. State‐of‐the‐art architectures and implementations are also presented, together with selected results of laboratory tests and scientific applications, which show the impressive performances and not yet explored potentialities of this class of mechanical accelerometers.
Effect of advective flow in fractures and matrix diffusion on natural gas production
Authors: Karra Satish , Makedonska Nataliia , Viswanathan Hari S. , Painter Scott L. , Hyman Jeffrey D.
Published: September 2015

Although hydraulic fracturing has been used for natural gas production for the past couple of decades, there are significant uncertainties about the underlying mechanisms behind the production curves that are seen in the field. A discrete fracture network‐based reservoir‐scale work flow is used to identify the relative effect of flow of gas in fractures and matrix diffusion on the production curve. With realistic three‐dimensional representations of fracture network geometry and aperture variability, simulated production decline curves qualitatively resemble observed production decline curves. The high initial peak of the production curve is controlled by advective fracture flow of free gas within the network and is sensitive to the fracture aperture variability. Matrix diffusion does not significantly affect the production decline curve in the first few years, but contributes to production after approximately 10 years. These results suggest that the initial flushing of gas‐filled background fractures combined with highly heterogeneous flow paths to the production well are sufficient to explain observed initial production decline. These results also suggest that matrix diffusion may support reduced production over longer time frames.
Modeling of long‐path propagation characteristics of VLF radio waves as observed from Indian Antarctic station Maitri
Authors: Sasmal Sudipta , Palit Sourav , Chakrabarti Sandip K.
Published: September 2015

Propagation of very low frequency (VLF) radio signal through the Earth‐ionosphere waveguide depends strongly on the plasma properties of the ionospheric D layer. Solar extreme ultraviolet radiation plays the central role in controlling physical and chemical properties of the lower ionospheric layers and hence determining the propagation characteristics of a VLF signal. The nature of interference among different propagating modes varies widely with the length of the propagation path. For a very long path, exposure of solar radiation and thus the degree of ionization vary by a large amount along the path. This influences the VLF signal profile by modulating the sky wave propagation. To understand the propagation characteristics over such a long path, we need a thorough investigation of the chemical reactions of the lower ionosphere which is lacking in the literature. Study of radio signal characteristics in the Antarctic region during summer period in the Southern Hemisphere gives us a unique opportunity to explore such a possibility. In addition, there is an extra feature in this path—the presence of solar radiation and hence the D region for the whole day during summer in at least some sections of the path. In this paper, we present long‐distance propagation characteristics of VLF signals transmitted from VTX (18.2 kHz) and NWC (19.8 kHz) transmitters recorded at the Indian permanent station Maitri (latitude 70°
S, longitude 114°
E) in 2007–2008. A very stable diurnal variation of the signal has been obtained with no signature of nighttime fluctuation due the presence of 24 h of sunlight. Using ion production and recombination profiles by solar irradiance and incorporating D region ion chemistry processes, we calculate the electron density profile at different heights. Using this profile in the Long Wavelength Propagation Capability code, we are able to reproduce the amplitude of VLF signal.
Interconnected Graphene Networks with Uniform Geometry for Flexible Conductors
Authors: Xiao Miao , Kong Tao , Wang Wei , Song Qin , Zhang Dong , Ma Qinqin , Cheng Guosheng
Published: September 2015

Controllable construction of graphene into specific architectures at macroscopic scales is crucial for practical applications of graphene. An approach of macroscopic and conductive interconnected graphene networks with controllable patterns, pore, and skeleton sizes via chemical vapor deposition is reported here. Specifically, the pore and skeleton sizes of 3D controllable graphene (3D‐CG) architectures can be tuned from 10 to 50 μm and the orientation angles of building blocks can be designed as 45° and 90°. The electrical conductivity and density of 3D‐CGs are measured at 60–80 S cm−1 and ≈3.6 mg cm−3, respectively. The properties of 3D‐CGs as flexible conductors and supercapacitor electrodes are reported, to explore the potential application in wearable devices and energy store.
Studies on the Synthesis of Specifically Fluorinated 4‐Amino‐ pyridine Derivatives by Regioselective Nucleophilic Aromatic Substitution and Catalytic Hydrodefluorination
Authors: Podolan Gabriel , Jungk Phillip , Lentz Dieter , Zimmer Reinhold , Reissig Hans‐Ulrich
Published: September 2015

The reactions of pentafluoropyridine and 2,4,6‐trifluoropyridine with a series of primary and secondary amines were studied. Whereas the nucleophilic aromatic substitution of pentafluoropyridine occurs with high regioselectivity in all cases, providing the expected 4‐aminopyridine derivatives in excellent yields, the regioselectivity of 2,4,6‐trifluoropyridine is dependent on the steric hindrance of the attacking nucleophile. Small nucleophiles such as morpholine attack the 4‐position of the pyridine ring with high preference, but more bulky diamines attack the 2‐ and 4‐positions leading to the formation of three regioisomeric products. (R,R)‐1,2‐Diaminocyclohexane as moderately bulky diamine reacted with 2,4,6‐trifluoropyridine to afford the desired bis(4‐aminopyridinyl)cyclohexane derivative in 30% yield. For hydrodefluorination two methods were examined. A two‐step procedure employing hydrazine and subsequently copper(II) sulfate removed just one fluorine substituent, but is not sufficiently high yielding for the reduction of more complex substrates. With the system titanocene difluoride as pre‐catalyst and diphenylsilane as reducing agent we were able to selectively remove fluorine substituents at positions C‐2 and C‐4 of a variety of 4‐aminopyridine derivatives. This protocol allows the synthesis of compounds such as the divalent chiral 4‐(dimethylamino)pyridine (DMAP) analogue (R,R)‐trans‐N,N′‐dimethyl‐N,N′‐bis(pyridin‐4‐yl)cyclohexane‐1,2‐diamine with fair overall yield.

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Long‐term testing of a high temperature polymer electrolyte membrane fuel cell: The effect of reactant gases
Authors: Pinar F. Javier , Pilinski Nadine , Wagner Peter
Published: September 2015

The investigations have been conducted with different oxidants and fuels with the aim of determining the state‐of‐the‐art of commercially available high temperature polymer electrolyte fuel cells based on polybenzimidazole for its application in combined heat and power generation systems. The fuel cell test performed with synthetic reformate (−63 μV/h) showed an increase of anode charge and mass transfer resistances. This behavior has suggested that CO may be generated from the CO2 included in the synthetic reformate via reverse water gas shift reaction. The fuel cell test performed with pure O2 developed the highest degradation rates (−70 μV/h) due to fast oxidative degradation of membrane electrode assembly materials such as cathode catalyst and membrane. Fuel cell operation with H2/air exhibited the lowest degradation rates (−57 μV/h) and it requires longer investigating times to identify the different degradation mechanisms. Moreover, fuel cell tests performed with air suggested longer break‐in procedures to complete catalyst activation and redistribution of electrolyte. © 2015 American Institute of Chemical Engineers AIChE J, 62: 217–227, 2016
Integrating compressors into heat exchanger networks above ambient temperature
Authors: Fu Chao , Gundersen Truls
Published: September 2015

Heat from compression processes is normally wasted to cooling water due to its low temperature or concerns about operability. The recoverable amount of heat can be enhanced by increasing the operating temperature of compressors. However, the compression work also increases under this condition. The integration of compressors into heat exchanger networks (HENs) is complex since both heat and work are involved, and the role of streams (as hot or cold streams), the utility demand, and the location of pinch points may change. A systematic graphical design procedure for above ambient HEN design including compressors was presented. The objective is to minimize exergy consumption to balance the complex heat‐work trade‐offs involved. Four theorems are proposed as the basis of the design procedure with certain well‐defined assumptions. It is found that the compression should be performed at pinch or ambient temperatures to achieve minimum exergy consumption. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3770–3785, 2015
Attentional biases to emotional stimuli: Key components of the RDoC constructs of sustained threat and loss
Authors: Gibb Brandon E. , McGeary John E. , Beevers Christopher G.
Published: September 2015

Biased attention to emotional stimuli plays a key role in the RDoC constructs of Sustained Threat and Loss. In this article, we review approaches to assessing these biases, their links with psychopathology, and the underlying neural influences. We then review evidence from twin and candidate gene studies regarding genetic influences on attentional biases. We also discuss the impact of developmental and environmental influences and end with a number of suggestions for future research in this area. © 2015 Wiley Periodicals, Inc.
Management of cerebrospinal fluid rhinorrhea: an evidence‐based review with recommendations
Authors: Oakley Gretchen M. , Orlandi Richard R. , Woodworth Bradford A. , Batra Pete S. , Alt Jeremiah A.
Published: September 2015

Background

Management strategies employed for cases of cerebrospinal fluid (CSF) rhinorrhea vary widely because of limited evidence‐based guidance.

Methods

A systematic review of the literature was performed using PubMed, EMBASE, and Cochrane databases from January 1990 through September 2014 to examine 5 endoscopic repair techniques and 8 perioperative management strategies for CSF rhinorrhea. Benefit‐harm assessments, value judgments, and recommendations were made based on the available evidence. Study exclusion criteria were language other than English, pre‐1990 studies, case reports, and nonrhinologic leak. All authors agreed on recommendations through an iterative process.

Results

We reviewed 67 studies examining 13 practices pertinent to the management of CSF rhinorrhea, reaching a highest aggregate grade of evidence of B. The literature does not support the routine use of prophylactic antibiotics or lumbar drainage. Various endoscopic repair materials show similar success rates; however, larger defects may benefit from vascularized grafts. There were no relevant studies to address postoperative activity restrictions.

Conclusion

Despite relatively low levels of evidence, recommendations for the management of CSF rhinorrhea can be made based on the current literature. Higher‐level studies are needed to better determine optimal clinical management approaches.
Quinidine in the treatment of KCNT1‐positive epilepsies
Authors: Mikati Mohamad A , Jiang Yong‐hui , Carboni Michael , Shashi Vandana , Petrovski Slave , Spillmann Rebecca , Milligan Carol J. , Li Melody , Grefe Annette , McConkie Allyn , Berkovic Samuel , Scheffer Ingrid , Mullen Saul , Bonner Melanie , Petrou Steven , Goldstein David
Published: September 2015

We report 2 patients with drug‐resistant epilepsy caused by KCNT1 mutations who were treated with quinidine. Both mutations manifested gain of function in vitro, showing increased current that was reduced by quinidine. One, who had epilepsy of infancy with migrating focal seizures, had 80% reduction in seizure frequency as recorded in seizure diaries, and partially validated by objective seizure evaluation on EEG. The other, who had a novel phenotype, with severe nocturnal focal and secondary generalized seizures starting in early childhood with developmental regression, did not improve. Although quinidine represents an encouraging opportunity for therapeutic benefits, our experience suggests caution in its application and supports the need to identify more targeted drugs for KCNT1 epilepsies. Ann Neurol 2015;78:995–999
Surface‐modified MgO nanoparticle enhances the mechanical and direct‐current electrical characteristics of polypropylene/polyolefin elastomer nanodielectrics
Authors: Zhou Yao , He Jinliang , Hu Jun , Dang Bin
Published: September 2015

Polypropylene (PP)/polyolefin elastomer (POE) blends and MgO/PP/POE nanocomposites were fabricated by melt blending. The morphology, mechanical, and electrical properties of the nanocomposites were investigated. Scanning electron microscopy showed that the surface‐modified MgO nanoparticles were well dispersed in the polymer matrix at low loadings of less than 3 phr. X‐ray diffraction demonstrated that the crystalline phases of PP in the composites were changed and that the β phase significantly increased. An examination of the electrical properties revealed that the direct‐current (dc) electric breakdown strength and space‐charge suppression effect were remarkably improved by the introduction of the surface‐modified MgO nanoparticles. In addition, obvious enhancements in the tensile modulus and strength were obtained as a result of the synergistic toughening of the POE and MgO nanoparticles. Thus, MgO/PP/POE nanocomposites with enhanced mechanical and electrical properties have great potential to be used as recyclable insulation materials for high‐voltage dc cables with large transmission capacities and high operating temperatures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 132, 42863.
Experimental study on the penetration interfaces of pipes with different cross‐sections in overflow water‐assisted coinjection molding
Authors: Kuang Tang‐Qing , Zhou Kai , Wu Li‐Xuan , Zhou Guo‐Fa , Turng Lih‐Sheng
Published: September 2015

The residual wall thicknesses (RWT) of the skin and the inner layers are important quality indicators of water‐assisted co‐injection molding (WACIM) parts. The influences of the shape of the cavity cross section and the processing parameters, including the water pressure, water delay time, inner melt temperature, and inner melt flow rate, on the penetration of the inner melt and water were explored via experiments. The results showed that the shape of the penetration section of the inner melt was closer to the cavity section with round corners, while that of the water ended up being round. Both the penetration ratios of the inner melt and the water increased proportionally with increasing circle ratio. Both the minimum values of the total RWT and the inner melt RWT increased with increasing circle ratio. Both the maximum values of the total RWT and the inner melt RWT increased with increasing Max_D, which is the maximum distance between the inscribed circle center and the wall. Both the penetration ratios of the inner melt and the water increased with increasing water pressure, decreased with increasing water delay time, and increased with increasing inner melt flow rate and increasing inner melt temperature. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 132, 42866.
Testing independence of bivariate interval‐censored data using modified Kendall's tau statistic
Authors: Kim Yuneung , Lim Johan , Park DoHwan
Published: September 2015

In this paper, we study a nonparametric procedure to test independence of bivariate interval censored data; for both current status data (case 1 interval‐censored data) and case 2 interval‐censored data. To do it, we propose a score‐based modification of the Kendall's tau statistic for bivariate interval‐censored data. Our modification defines the Kendall's tau statistic with expected numbers of concordant and disconcordant pairs of data. The performance of the modified approach is illustrated by simulation studies and application to the AIDS study. We compare our method to alternative approaches such as the two‐stage estimation method by Sun et al. (Scandinavian Journal of Statistics, 2006) and the multiple imputation method by Betensky and Finkelstein (Statistics in Medicine, 1999b).
Pitfalls of hypothesis tests and model selection on bootstrap samples: Causes and consequences in biometrical applications
Authors: Janitza Silke , Binder Harald , Boulesteix Anne‐Laure
Published: September 2015

The bootstrap method has become a widely used tool applied in diverse areas where results based on asymptotic theory are scarce. It can be applied, for example, for assessing the variance of a statistic, a quantile of interest or for significance testing by resampling from the null hypothesis. Recently, some approaches have been proposed in the biometrical field where hypothesis testing or model selection is performed on a bootstrap sample as if it were the original sample. P‐values computed from bootstrap samples have been used, for example, in the statistics and bioinformatics literature for ranking genes with respect to their differential expression, for estimating the variability of p‐values and for model stability investigations. Procedures which make use of bootstrapped information criteria are often applied in model stability investigations and model averaging approaches as well as when estimating the error of model selection procedures which involve tuning parameters. From the literature, however, there is evidence that p‐values and model selection criteria evaluated on bootstrap data sets do not represent what would be obtained on the original data or new data drawn from the overall population. We explain the reasons for this and, through the use of a real data set and simulations, we assess the practical impact on procedures relevant to biometrical applications in cases where it has not yet been studied. Moreover, we investigate the behavior of subsampling (i.e., drawing from a data set without replacement) as a potential alternative solution to the bootstrap for these procedures.
Enhanced purification of plasmid DNA isoforms by exploiting ionic strength effects during ultrafiltration
Authors: Li Ying , Currie David , Zydney Andrew L.
Published: September 2015

The solution structure of plasmid DNA is known to be a strong function of solution conditions due to intramolecular electrostatic interactions between the charged phosphate groups along the DNA backbone. The objective of this work was to determine whether it was possible to enhance the use of ultrafiltration for separation of different plasmid isoforms by proper selection of the solution ionic strength and ion type. Experiments were performed with a 3.0 kbp plasmid using composite regenerated cellulose ultrafiltration membranes. The transmission of the linear isoform was nearly independent of solution ionic strength, but increased significantly with increasing filtrate flux due to the elongation of the highly flexible plasmid in the converging flow field into the membrane pores. In contrast, the transmission of the open‐circular and supercoiled plasmids both increased with increasing NaCl or MgCl2 concentration due to the change in plasmid size and conformational flexibility. The effect of ionic strength was greatest for the supercoiled plasmid, providing opportunities for enhanced purification of this therapeutically active isoform. This behavior was confirmed using experiments performed with binary mixtures of the different isoforms. These results clearly demonstrate the potential for enhancing the performance of membrane systems for plasmid DNA separations by proper selection of the ionic conditions. Biotechnol. Bioeng. 2016;113: 783–789. © 2015 Wiley Periodicals, Inc.
REVascularization with paclitaxEL‐coated balloon angioplasty versus drug‐eluting stenting in acute myocardial infarcTION—A randomized controlled trial: Rationale and design of the REVELATION trial
Authors: Vos Nicola S. , van der Schaaf Rene J. , Amoroso Giovanni , Herrman Jean‐Paul R. , Patterson Mark S. , Slagboom Ton , Vink Maarten A.
Published: September 2015

Aim

In primary percutaneous coronary intervention (PPCI) for ST‐elevation myocardial infarction (STEMI), stenting has proved to reduce the need for repeat revascularization compared with balloon angioplasty alone. The incidence of cardiac death or recurrent myocardial infarction, though, is not reduced by stenting. This is in part attributable to stent‐related complications like stent thrombosis which may occur even years after implantation. A strategy of drug coated balloon (DCB) angioplasty without stenting would abolish the potential disadvantages of stent implantation while reducing the probability of restenosis observed in plain old balloon angioplasty. Our aim is to evaluate the efficacy and safety of a DCB only strategy versus drug‐eluting stents (DES) in PPCI for STEMI.

Study design

The REVELATION trial is a prospective, single center, randomized study, in which 120 patients presenting with STEMI will be allocated to treatment with a DCB versus DES. Appertaining to the established prognostic value of fractional flow reserve (FFR) rather than angiographic lesion severity, the functional assessment of the infarct‐related lesion by FFR at 9 months after initial treatment is the primary end point. Assuming an FFR value of 0.90 after stenting and an increased risk of adverse events if post‐PCI FFR <0.85, we decided to accept an FFR value of ≥0.85 after DCB only at follow‐up as noninferiority margin. Secondary end points include major adverse cardiac events up to 5‐year follow‐up.

Conclusion

Our trial will address the efficacy and safety of DCB angioplasty versus DES in the setting of PPCI for STEMI. The REVELATION trial will introduce the recognized prognostic significance of physiologic assessment of the infarct‐related lesion by FFR at 9 months follow‐up as primary end point. © 2015 Wiley Periodicals, Inc.