bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of high‐resolution near‐surface freeze/thaw state by the integration of microwave and thermal infrared remote sensing data on the Tibetan Plateau
Authors: Zhao Tianjie , Shi Jiancheng , Hu Tongxi , Zhao Lin , Zou Defu , Wang Tianxing , Ji Dabin , Li Rui , Wang Pingkai
Published: July 2017

The objective of this study is to investigate how the complementarity between microwave and thermal infrared remote sensing can be exploited for a high‐resolution near‐surface freeze/thaw state estimation. The basic idea is to establish a feasible relationship between the microwave‐derived freeze/thaw state and thermal infrared observations. A quantitative freeze/thaw index from microwave observations at 18.7 and 36.5 GHz is innovatively defined and is assumed to be linearly correlated with land surface temperature from thermal infrared observations. Thus, a linear regression method is proposed and verified to be effective over a multiscale network of Naqu of the Tibetan Plateau. In order to demonstrate the potentiality of the proposed method, it is implemented in the entire Tibetan Plateau. It is found that the linear relationship is quite reliable for most areas and can obtain a high‐resolution near‐surface soil freeze/thaw state with integrated information from microwave and thermal infrared remote sensing. The validation of the high‐resolution freeze/thaw state against soil temperature measured at active layer monitoring sites along the Qinghai‐Tibet Highway illustrates a moderate accuracy over a decade scale. This study provides new insights for high‐resolution freeze/thaw mapping beyond the Soil Moisture Active Passive mission.
Intercomparison between CMIP5 model and MODIS satellite‐retrieved data of aerosol optical depth, cloud fraction, and cloud‐aerosol interactions
Authors: Sockol Alyssa , Small Griswold Jennifer D.
Published: July 2017

Aerosols are a critical component of the Earth's atmosphere and can affect the climate of the Earth through their interactions with solar radiation and clouds. Cloud fraction (CF) and aerosol optical depth (AOD) at 550 nm from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used with analogous cloud and aerosol properties from Historical Phase 5 of the Coupled Model Intercomparison Project (CMIP5) model runs that explicitly include anthropogenic aerosols and parameterized cloud‐aerosol interactions. The models underestimate AOD by approximately 15% and underestimate CF by approximately 10% overall on a global scale. A regional analysis is then used to evaluate model performance in two regions with known biomass burning activity and absorbing aerosol (South America (SAM) and South Africa (SAF)). In SAM, the models overestimate AOD by 4.8% and underestimate CF by 14%. In SAF, the models underestimate AOD by 35% and overestimate CF by 13.4%. Average annual cycles show that the monthly timing of AOD peaks closely match satellite data in both SAM and SAF for all except the Community Atmosphere Model 5 and Geophysical Fluid Dynamics Laboratory (GFDL) models. Monthly timing of CF peaks closely match for all models (except GFDL) for SAM and SAF. Sorting monthly averaged 2° × 2.5° model or MODIS CF as a function of AOD does not result in the previously observed “boomerang”‐shaped CF versus AOD relationship characteristic of regions with absorbing aerosols from biomass burning. Cloud‐aerosol interactions, as observed using daily (or higher) temporal resolution data, are not reproducible at the spatial or temporal resolution provided by the CMIP5 models.
Simultaneous stabilization of global temperature and precipitation through cocktail geoengineering
Authors: Cao Long , Duan Lei , Bala Govindasamy , Caldeira Ken
Published: July 2017

Solar geoengineering has been proposed as a backup plan to offset some aspects of anthropogenic climate change if timely CO2 emission reductions fail to materialize. Modeling studies have shown that there are trade‐offs between changes in temperature and hydrological cycle in response to solar geoengineering. Here we investigate the possibility of stabilizing both global mean temperature and precipitation simultaneously by combining two geoengineering approaches: stratospheric sulfate aerosol increase (SAI) that deflects sunlight to space and cirrus cloud thinning (CCT) that enables more longwave radiation to escape to space. Using the slab ocean configuration of National Center for Atmospheric Research Community Earth System Model, we simulate SAI by uniformly adding sulfate aerosol in the upper stratosphere and CCT by uniformly increasing cirrus cloud ice particle falling speed. Under an idealized warming scenario of abrupt quadrupling of atmospheric CO2, we show that by combining appropriate amounts of SAI and CCT geoengineering, global mean (or land mean) temperature and precipitation can be restored simultaneously to preindustrial levels. However, compared to SAI, cocktail geoengineering by mixing SAI and CCT does not markedly improve the overall similarity between geoengineered climate and preindustrial climate on regional scales. Some optimal spatially nonuniform mixture of SAI with CCT might have the potential to better mitigate climate change at both the global and regional scales.
Statistical properties of low‐frequency plasmaspheric hiss
Authors: Malaspina David M. , Jaynes Allison N. , Hospodarsky George , Bortnik Jacob , Ergun Robert E. , Wygant John
Published: July 2017

Plasmaspheric hiss is an important wave mode for the dynamics of inner terrestrial magnetosphere plasma populations. It acts to scatter high‐energy electrons out of trapped orbits about Earth and into the atmosphere, defining the inner edge of the radiation belts over a range of energies. A low‐frequency component of hiss was recently identified and is important for its ability to interact with higher‐energy electrons compared to typically considered hiss frequencies. This study compares the statistical properties of low‐ and high‐frequency plasmaspheric hiss in the terrestrial magnetosphere, demonstrating that they are statistically distinct wave populations. Low‐frequency hiss shows different behavior in frequency space, different spatial localization (in magnetic local time and radial distance), and different amplitude distributions compared to high‐frequency hiss. The observed statistical properties of low‐frequency hiss are found to be consistent with recently developed theories for low‐frequency hiss generation. The results presented here suggest that careful consideration of low‐frequency hiss properties can be important for accurate inclusion of this wave population in predictive models of inner magnetosphere plasma dynamics.
The dynamics of volcanic jets: Temporal evolution of particles exit velocity from shock‐tube experiments
Authors: Cigala V. , Kueppers U. , Peña Fernández J. J. , Taddeucci J. , Sesterhenn J. , Dingwell D. B.
Published: July 2017

Pyroclast ejection during explosive volcanic eruptions occurs under highly dynamic conditions involving great variations in flux, particle sizes, and velocities. This variability must be a direct consequence of complex interactions between physical and chemical parameters inside the volcanic plumbing system. The boundary conditions of such phenomena cannot be fully characterized via field observation and indirect measurements alone. In order to understand better eruptive processes, we conducted scaled and controlled laboratory experiments. By performing shock‐tube experiments at known conditions, we defined the influence of physical boundary conditions on the dynamics of pyroclast ejection. If applied to nature, we are focusing in the near‐vent processes where, independently of fragmentation mechanism, impulsively released gas‐pyroclast mixtures can be observed. These conditions can be met during, e.g., Strombolian or Vulcanian eruptions, parts of Plinian eruptions, or phreatomagmatic explosions. The following parameters were varied: (1) tube length, (2) vent geometry, (3) particle load, (4) temperature, and (5) particle size distribution. Gas and particles in the experiments are not coupled (St >> 1). The initial overpressure, with respect to atmosphere, was always at 15 MPa. We found a positive correlation of pyroclast ejection velocity with (1) particle load, (2) diverging vent walls, and (3) temperature as well as a negative correlation with (1) tube length and (2) particle size. Additionally, we found that particle load strongly affects the temporal evolution of particle ejection velocity. These findings stress the importance of scaled and repeatable laboratory experiments for a better understanding of volcanic phenomena and therefore volcanic hazard assessment.
Connecting crustal seismicity and earthquake‐driven stress evolution in Southern California
Authors: Pollitz Fred F. , Cattania Camilla
Published: July 2017

Tectonic stress in the crust evolves during a seismic cycle, with slow stress accumulation over interseismic periods, episodic stress steps at the time of earthquakes, and transient stress readjustment during a postseismic period that may last months to years. Static stress transfer to surrounding faults has been well documented to alter regional seismicity rates over both short and long time scales. While static stress transfer is instantaneous and long lived, postseismic stress transfer driven by viscoelastic relaxation of the ductile lower crust and mantle leads to additional, slowly varying stress perturbations. Both processes may be tested by comparing a decade‐long record of regional seismicity to predicted time‐dependent seismicity rates based on a stress evolution model that includes viscoelastic stress transfer. Here we explore crustal stress evolution arising from the seismic cycle in Southern California from 1981 to 2014 using five M≥6.5 source quakes: the M7.3 1992 Landers, M6.5 1992 Big Bear, M6.7 1994 Big Bear, M7.1 1999 Hector Mine, and M7.2 2010 El Mayor‐Cucapah earthquakes. We relate the stress readjustment in the surrounding crust generated by each quake to regional seismicity using rate‐and‐state friction theory. Using a log likelihood approach, we quantify the potential to trigger seismicity of both static and viscoelastic stress transfer, finding that both processes have systematically shaped the spatial pattern of Southern California seismicity since 1992.
Variety and sustainability of volcanic lakes: Response to subaqueous thermal activity predicted by a numerical model
Authors: Terada Akihiko , Hashimoto Takeshi
Published: July 2017

We use a numerical model to investigate the factors that control the presence or absence of a hot crater lake at an active volcano. We find that given a suitable pair of parameters (e.g., the enthalpy of subaqueous fumaroles and the ratio of mass flux of the fluid input at the lake bottom to lake surface area), hot crater lakes can be sustained on relatively long timescales. Neither a high rate of precipitation nor an impermeable layer beneath the lake bottom are always necessary for long‐term sustainability. The two controlling parameters affect various hydrological properties of crater lakes, including temperature, chemical concentrations, and temporal variations in water levels. In the case of low‐temperature crater lakes, increases in flux and enthalpy, which are a common precursor to phreatic or phreatomagmatic eruptions, result in an increase in both temperature and water level. In contrast, a decrease in water level accompanied by a rise in temperature occurs at high‐temperature lakes. Furthermore, our model suggests that crater geometry is a key control on water temperature. For lakes with a conical topography, a perturbation in the water level due to trivial nonvolcanic activity, such as low levels of precipitation, can cause persistent increases in water temperature and chemical concentrations, and a decrease in the water level, even though subaqueous fumarolic activity does not change. Such changes in hot crater lakes which are not caused by changes in volcanic activity resemble the volcanic unrest that precedes eruptions.
Texture, Microstructure, and Surface Mechanical Properties of AZ31 Magnesium Alloys Processed by ECASD
Authors: Fandiño Emigdio Mendoza , Bolmaro Raúl E. , Risso Pablo , Tartalini Vanina , Morales Patricia Fernández , Ávalos Martina
Published: July 2017

The current work presents the results on Mg AZ31B alloy sheets subject to four passes using Equal Channel Angular Sheet Drawing (ECASD) at various temperatures (25, 100, and 200 °C). Textures are determined by laboratory X‐ray diffraction and EBSD. EBSD allows the evaluation of the evolution of crystal sizes in function of the distance to the surface and the presence of twinning. Twinning is evident by the analysis of the textures, which show mainly two components, one due to the spin induced by the shearing of ECASD and the other one as a direct product of twinning. Micro‐hardness, by Knoop tests on the lateral face of the sheets, are performed, allowing the determination of the influence of SPD on the hardness from surface to surface, going through the center of the sheet. Almost 50% increase on hardening, with respect to the non‐processed material, is obtained near to the surface after four and six passes. The effectiveness as a hardening technique declined after the first four passes.
A Low‐Cost, Self‐Standing NiCo2O4@CNT/CNT Multilayer Electrode for Flexible Asymmetric Solid‐State Supercapacitors
Authors: Wu Peng , Cheng Shuang , Yao Minghai , Yang Lufeng , Zhu Yuanyuan , Liu Peipei , Xing Ou , Zhou Jun , Wang Mengkun , Luo Haowei , Liu Meilin
Published: July 2017

The demand for a new generation of flexible, portable, and high‐capacity power sources increases rapidly with the development of advanced wearable electronic devices. Here we report a simple process for large‐scale fabrication of self‐standing composite film electrodes composed of NiCo2O4@carbon nanotube (CNT) for supercapacitors. Among all composite electrodes prepared, the one fired in air displays the best electrochemical behavior, achieving a specific capacitance of 1,590 F g−1 at 0.5 A g−1 while maintaining excellent stability. The NiCo2O4@CNT/CNT film electrodes are fabricated via stacking NiCo2O4@CNT and CNT alternately through vacuum filtration. Lightweight, flexible, and self‐standing film electrodes (≈24.3 µm thick) exhibit high volumetric capacitance of 873 F cm−3 (with an areal mass of 2.5 mg cm−2) at 0.5 A g−1. An all‐solid‐state asymmetric supercapacitor consists of a composite film electrode and a treated carbon cloth electrode has not only high energy density (≈27.6 Wh kg−1) at 0.55 kW kg−1 (including the weight of the two electrodes) but also excellent cycling stability (retaining ≈95% of the initial capacitance after 5000 cycles), demonstrating the potential for practical application in wearable devices.
An Interplay between Matrix Anisotropy and Actomyosin Contractility Regulates 3D‐Directed Cell Migration
Authors: Caballero David , Palacios Lucas , Freitas Paulo P. , Samitier Josep
Published: July 2017

Directed cell migration is essential for many biological processes, such as embryonic development or cancer progression. Cell contractility and adhesion to the extracellular matrix are known to regulate cell locomotion machinery. However, the cross‐talk between extrinsic and intrinsic factors at the molecular level on the biophysical mechanism of three dimensional (3D)‐directed cell migration is still unclear. In this work, a novel physiologically relevant in vitro model of the extracellular microenvironment is used to reveal how the topological anisotropy of the extracellular matrix synergizes with actomyosin contractility to modulate directional cell migration morphodynamics. This study shows that cells seeded on polarized 3D matrices display asymmetric protrusion morphodynamics and in‐vivo‐like phenotypes. It is found that matrix anisotropy significantly enhances cell directionality, but strikingly, not the invasion distance of cells. In Rho‐inhibited cells, matrix anisotropy counteracts the lack of actomyosin‐driven forces to stabilize cell directionality suggesting a myosin‐II‐independent mechanism for cell guidance. Finally, this study shows that on isotropic 3D environments, cell directionality is independent of actomyosin contractility. Altogether, this study provides novel quantitative data on the biomechanical regulation of directional cell motion and shows the important regulatory role of matrix anisotropy and actomyosin forces to guide cell migration in 3D microenvironments.
Controlled Exposure of Bioactive Growth Factor in 3D Amyloid Hydrogel for Stem Cells Differentiation
Authors: Das Subhadeep , Kumar Rakesh , Jha Narendra Nath , Maji Samir K.
Published: July 2017

Amyloid based hydrogels can mimic the extracellular matrix and serve as matrices for tissue engineering both in vitro and in vivo. A pH responsive self‐assembled amyloid hydrogel system is used to encapsulate various growth factors for driving stem cell differentiation toward neuronal lineage. Diffusion studies with fluorescence recovery after photobleaching and bulk release with the model protein fluorescein isothiocyanate‐bovine serum albumin show that encapsulated protein molecules can be released in a sustained fashion from the hydrogel over a considerable period of time (30 d). Moreover, by modulating the porosity of the hydrogel by the simple addition of salt, the encapsulated protein molecules can be retained for a longer period of time within the hydrogel. Mesenchymal stem cells, when cultured in 3D amyloid hydrogels with growth factors fibroblast growth factor 8 and sonic hedgehog, show more neuron specific differentiation as compared to hydrogel alone. This higher differentiation potential of growth factor encapsulated amyloid hydrogels can be due to concomitant exposure of cells to biomechanical as well as biochemical cues during the course of differentiation. The present study suggests that amyloid based hydrogel can be exploited for controlled growth factor delivery as well as directed stem cell differentiation to neuron.
Newly Designed Silica‐Containing Redox Nanoparticles for Oral Delivery of Novel TOP2 Catalytic Inhibitor for Treating Colon Cancer
Authors: Vong Long Binh , Kimura Shinya , Nagasaki Yukio
Published: July 2017

Although oral drug delivery is the most common route of drug administration, the conventional polymeric nanocarriers exhibit a low drug loading capacity and low stability in the gastrointestinal (GI) environments. In this study, a newly designed silica‐containing redox nanoparticle (siRNP) with reactive oxygen species (ROS) scavenging capacity is developed as an ideal oral nanocarrier for a novel hydrophobic anticancer compound BNS‐22 to treat colitis‐associated colon cancer in vivo. Crosslinking of silica moieties significantly enhances the stability under acidic conditions and improves BNS‐22 loading capacity of siRNP compared to the conventional redox nanoparticle. After oral administration to mice, BNS‐22‐loaded siRNP (BNS‐22@siRNP) remarkably improves bioavailability and colonic tumor distribution of BNS‐22. As the result, BNS‐22@siRNP significantly inhibits the tumor progression in colitis‐associated colon cancer mice compared to other control treatments. It is noteworthy that no systemic absorption of siRNP carrier is observed after oral administration. Interestingly, orally administered BNS‐22@siRNP significantly suppresses the adverse effects of BNS‐22 owing to its ROS scavenging capacity, and no other noticeable toxicities are observed in mice treated with BNS‐22@siRNP although siRNP is localized in the GI tract. Our results indicate that siRNP is a promising oral drug nanocarrier for cancer therapy.
Low‐Cost, Facile, and Scalable Manufacturing of Capacitive Sensors for Soft Systems
Authors: White Edward L. , Yuen Michelle C. , Case Jennifer C. , Kramer Rebecca K.
Published: July 2017

In the field of soft robotics there is a need for robust and reliable large‐deformation strain sensing. Further, the field needs a way to produce such sensors in large quantities and at low cost. Toward these goals, the fabrication of highly stretchable capacitive strain sensors made from conductive elastomer composites is described here. Two novel methods of manufacturing these sensors directly onto a fabric substrate are developed: direct writing of elastomer using an extrusion process and screen printing of elastomer patterns. The effect of material processing parameters on the parameters of the finished composite films is studied and it is determined that the process is robust to a wide range of variations. The performance of sensors produced on fabric substrates is shown to be similar between the two fabrication processes. Further, the sensors are highly deformable with consistent performance up to 250% strain, and are reliable, with no changes in performance observed at 1000 cycles. It is also demonstrated that the sensors continue to perform with reduced gauge factors up to 100 000 cycles. For comparison, free‐standing capacitive sensors are also produced with the same materials and it is shown that these devices are equally stable and robust. In conclusion, the fabrication process demonstrated here is robust to process variations and is capable of producing sensors directly on fabric substrates, which facilitates the production of large arrays of sensors without the need for an additional assembly step.
Introduction of Twisted Backbone: A New Strategy to Achieve Efficient Blue Fluorescence Emitter with Delayed Emission
Authors: Liu Ming , Komatsu Ryutaro , Cai Xinyi , Sasabe Hisahiro , Kamata Takahiro , Nakao Kouhei , Liu Kunkun , Su Shi‐Jian , Kido Junji
Published: July 2017

By introducing an acceptor which contains double sulfonyl groups and a twisted biphenyl core, an efficient blue thermally activated delayed fluorescence emitter is successfully developed. Comparative study and analysis are carried out on it with an analogous molecule, which also imports two sulfonyl groups as acceptors and exactly same donor units but shows stretched shape and displays green emission. Results of quantum chemistry computation estimate that the introduction of such a twisted backbone is beneficial to increase energies of both singlet and triplet states. As a contrast to its counterpart, the newly developed blue emission compound with contorted structure enables a desirable emission with a peak wavelength of 460 nm and superior photoluminescence quantum yield up to 82%. Moreover, remarkable external quantum efficiency over 24% and Commission International de l'Eclairage coordinates with total (x + y) value <0.4 are achieved from the electroluminescent device based on the blue emitter, while this value is almost twice to that of the green emission device based on its analog.
Crystallization‐Induced Emission Enhancement and Amplified Spontaneous Emission from a CF3‐Containing Excited‐State Intramolecular‐Proton‐Transfer Molecule
Authors: Park Sanghyuk , Kwon Ji Eon , Park Sun‐Young , Kwon Oh‐Hoon , Kim Joon Ki , Yoon Seong‐Jun , Chung Jong Won , Whang Dong Ryeol , Park Sang Kyu , Lee Dong Ki , Jang Du‐Jeon , Gierschner Johannes , Park Soo Young
Published: July 2017

In this work, a simple but effective molecular design strategy is developed for the generation of intense blue emission in the solid state including single crystals through the multiple secondary intermolecular interactions such as CF…HC hydrogen bonding. The synthesized novel imidazole‐based excited‐state intramolecular proton transfer (ESIPT) molecule, 2‐(1‐(3,5‐bis(trifluoromethyl)phenyl)‐4,5‐diphenyl‐1H‐imidazol‐2‐yl)phenol (HPI‐CF3), shows significantly enhanced blue fluorescence in single crystal (ΦF = 0.67) compared to faint emission in solution (ΦF < 0.05). It is considered that tight but slipped stacking structure of HPI‐CF3 molecules in the single crystal not only effectively suppresses the nonradiative decay pathways such as twist intramolecular charge transfer but also induces highly allowed transition character. Taking advantage of the crystallization‐induced emission enhancement characteristics and four‐level ESIPT photocycle process of HPI‐CF3, an efficient amplified spontaneous emission at 475 nm with a threshold of 13.1 mJ cm−2 is observed from the single crystal by picosecond laser optical pumping.
Polythiophene–Peptide Biohybrid Assemblies for Enhancing Photoinduced Hydrogen Evolution
Authors: Lu Huan , Zhou Chengcheng , Zhou Xin , Sun Han , Bai Haotian , Wang Yunxia , Lv Fengting , Liu Libing , Ma Yuguo , Wang Shu
Published: July 2017

The self‐assembly of short peptide offers versatile processes for adjusting the ordered stacking of organic functional materials to enhance photoinduced electron transfer. Herein, this study presents the first demonstration of the use of Aβ16–22 peptide to prepare polythiophene/Aβ16–22 assemblies for a photocatalytic water splitting system. Isothermal titration microcalorimetry results show that the driving forces for polythiophene/Aβ16–22 assembly formation are electrostatic interactions, as well as hydrogen bonds and hydrophobic interactions. The assemblies accelerate the photoinduced electrons transfer from polythiophene upon light excitation and eventually enhance the hydrogen evolution. This work opens a new way into the development of biohybrid materials as novel photocatalytic water splitting platform for hydrogen evolution.
TiO2 Nanocrystal/Perovskite Bilayer for High‐Performance Photodetectors
Authors: Yi Xiaohui , Ren Zhenwei , Chen Ningli , Li Cheng , Zhong Xinhua , Yang Shiyong , Wang Jizheng
Published: July 2017

Owing to their attractive performance in photovoltaic devices, organolead halide perovskite materials have attracted enormous interest for photodetector applications. However, current perovskite‐based photodetectors mainly rely on high‐conductive 2D materials such as graphene or transition metal sulfides to transport photocarriers, which indeed significantly improve the photoresponsivity but seriously weaken other parameters such as on/off ratio or response speed. Achieving a high overall performance remains a challenge. Here, a solution‐processed TiO2 nanocrystal (NC) film is employed to transport photocarriers. The designed TiO2 NC/perovskite (CH3NH3PbI3) bilayer device exhibits satisfactory overall performance with on/off ratio of 4000, photodetectivity of 1.85 × 1012 Jones, and rise/decay time of 0.49/0.56 s. The device can also be integrated on flexible polyimide substrate. This work provides a strategy to realize high‐performance perovskite‐based photodetectors and clearly demonstrates their potential applications in future flexible optoelectronics.
The Effect of Pressure on Organic Reactions in Fluids—a New Theoretical Perspective
Authors: Chen Bo , Hoffmann Roald , Cammi Roberto
Published: July 2017

This Review brings a new perspective to the study of chemical reactions in compressed fluid media. We begin by reviewing the substantial insight gained from more than 50 years of experimental studies on organic reactions in solution under pressure. These led to a proper estimation of the critical roles of volume of activation (Δ≠V) and reaction volume (ΔV) in understanding pressure effect on rates and equilibria of organic reactions. A recently developed computational method, the XP‐PCM (extreme pressure polarizable continuum model) method, capable of carrying out quantum mechanical calculations of reaction pathways of molecules under pressure, is introduced. A case study of the Diels–Alder cycloaddition of cyclopentadiene with ethylene serves, in pedagogical detail, to describe the methodology. We then apply the XP‐PCM method to a selection of other pericyclic reactions, including the parent Diels–Alder cycloaddition of butadiene with ethylene, electrocyclic ring‐opening of cyclobutene, electrocyclic ring‐closing of Z‐hexatriene, the [1,5]‐H shift in Z‐pentadiene, and the Cope rearrangement. These serve as examples of some of the most common combinations of Δ≠V and ΔV. Interesting phenomena such as a shift in a transition state along a reaction coordinate, a switch of rate‐determining step, and the possible turning of a transition state into a stable minimum are revealed by the calculations. A reaction volume profile, the change in the volume of the reacting molecules as the reaction proceeds, emerges as being useful.
Development of ethanolamine‐based ionic liquid membranes for efficient CO2/CH4 separation
Authors: Ur Rehman Rashid , Rafiq Sikander , Muhammad Nawshad , Khan Asim Laeeq , Ur Rehman Asif , TingTing Liu , Saeed Muhammad , Jamil Farrukh , Ghauri Moinuddin , Gu Xuehong
Published: July 2017

This study is focused on the development of ionic liquids (ILs) based polymeric membranes for the separation of carbon dioxide (CO2) from methane (CH4). The advantage of ILs in selective CO2 absorption is that it enhances the CO2 selective separation for the ionic liquid membranes (ILMs). ILMs are developed and characterized with two different ILs using the solution‐casting method. Three different blend compositions of ILs and polysulfone (PSF) are selected for each ILMs 10, 20, and 30 wt %. Effect of the different types of ILs such as triethanolamine formate (TEAF) and triethanolamine acetate (TEAA) are investigated on PSF‐based ILMs. Field emission scanning electron microscopy analysis of the membranes showed reasonable homogeneity between the ILs and PSF. Thermogravimetric analysis showed that by increasing the ILs loading thermal stability of the membranes improved. Mechanical analysis on developed membranes showed that ILs phase reduced the amount of plastic flow of the PSF phase and therefore, fracture takes place at gradually lower strains with increasing ILs content. Gas permeation evaluation was carried out on the developed membranes for CO2/CH4 separation between 2 bar to 10 bar feed pressure. Results showed that CO2 permeance increases with the addition of ILs 10–30 wt % in ILMs. With 20–30 wt % TEAF‐ILMs and TEAA‐ILMs, the highest selectivity of a CO2/CH4 53.96 ± 0.3, 37.64 ± 0.2 and CO2 permeance 69.5 ± 0.6, 55.21 ± 0.3 is observed for treated membrane at 2–10 bar. The selectivity using mixed gas test at various CO2/CH4 compositions shows consistent results with the ideal gas selectivity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45395.
Synthesis and thiol–ene photopolymerization of (meth)allyl‐terminated polysulfides
Authors: Brei Mark R. , Donovan Brian R. , Patton Derek L. , Storey Robson F.
Published: July 2017

Thiol‐terminated polysulfides (PS) are cured by mixing with an oxidant, resulting in limited shelf‐ and/or pot‐life, depending on whether formulated as a one‐ or two‐component system. Mixtures of thiol‐ and alkene‐terminated polysulfides offer the potential for an on‐demand curing process through thiol–ene photopolymerization. Thiol end groups of commercial polysulfides, PS‐1 (1000 g/mol) and PS‐2 (3000 g/mol), were converted to alkene by reaction with (meth)allyl bromide. Photopolymerizations were performed by irradiating films of equimolar thiol:ene mixtures at 320–500 nm (30 mW/cm2) in the presence of 5 wt % 2,2‐dimethoxy‐2‐phenyl‐acetophenone (DMPA). Reaction kinetics were measured using real‐time FTIR by monitoring absorbances at 3075 cm−1 (alkene) or 2550 cm−1 (thiol). In the absence of any reactive diluent, mixtures of thiol and alkene polysulfides failed to gel notwithstanding high reaction conversion (>90%). Partial or total replacement of the thiol polysulfide component with pentaerythritol tetrakis(3‐mercaptopropionate) (PETMP) yielded solid elastomeric films and ultimate reaction conversions of 80–96% after 5 min irradiation. Crosshatch adhesion measured on glass, aluminum, and steel was very poor (0B) for (meth)allyl PS‐1/PETMP and poor (2B) for (meth)allyl PS‐2/PETMP without adhesion promoters. (3‐Mercaptopropyl)trimethoxysilane (1 wt %) significantly improved adhesion of (meth)allyl PS‐2/PETMP on all substrates (4B) but yielded no improvement for (meth)allyl‐terminated PS‐1/PETMP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45523.
Solution self‐assembly behavior of A‐B‐C triblock polymers and the implications for nanoporous membrane fabrication
Authors: Sargent Jessica L. , Hoss Darby J. , Phillip William A. , Boudouris Bryan W.
Published: July 2017

Self‐assembled block polymer membranes are rising to the fore of next‐generation separations technologies, and a particular fabrication process of significant interest is the self‐assembly and non‐solvent induced phase‐separation (SNIPS) method. This is because the SNIPS process allows for the facile manipulation of independent variables to produce simultaneously size‐ and chemically‐selective membranes in a scalable manner. Despite significant advances in the SNIPS membrane fabrication procedure, the early‐stage solution behavior of many of the polymer–solvent systems employed is still poorly understood. This work addresses the challenges posed by these systems and illuminates guiding relationships for the optimization of SNIPS membrane casting solutions. Specifically, polymer aggregate structures and critical micelle concentration (CMC) values are determined for an A‐B‐C triblock polymer dissolved in 1,4‐dioxane using a combination of scattering and atomic force microscopy techniques. The CMC of this system ranges from 20 to 80 μM and shows a strong dependence on the polymer composition and solution processing method. Additionally, the shape of the self‐assembled structures in solution can be altered by varying these parameters. These studies establish the relationships between polymer solution properties (i.e., the block polymer composition and the processing method) and assembly behavior as they impact membrane fabrication through SNIPS processing. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45531.
Water‐soluble, antiyellowing polymeric fluorescence brighteners
Authors: Guo Mingyuan , Zhang Guanghua , Du Lun , Zheng Hua , Liu Guojun
Published: July 2017

In this study, a type of polymeric fluorescence brightener (PFB) with a triazine–stilbene structure was synthesized through a three‐step condensation reaction, and the performance of this PFB on antiyellowing was also investigated by the whiteness of paper coated with the as‐prepared PFB. Fourier transform infrared spectra revealed that the chlorine atom (·Cl) was substituted by a poly(vinyl alcohol) (PVA) group ([CH2CHOH]n). According to the UV aging experiment, the PFB not only enhanced the whiteness of the paper but also improved the anti‐UV aging properties [compared to those of VBL 4′‐double‐(6‐diethanolamine‐4‐sulfanilic acid‐1,3,5‐triazine‐2‐amino)‐stilbene‐2,2′‐disulfonic acid sodium, a type of commonly used fluorescent whitening agent as a light stabilizer and fluorescent brightening agent]. Moreover, the results of UV–visible spectra indicated that the substitution of PVA suppressed the isomerization of trans conformers to cis conformers under UV light irradiation; this was attributed to the big space steric hindrance of PVA in the as‐prepared samples being restricted the isomerization reaction. Meanwhile, the solubility of the as‐prepared sample was also improved because more hydroxyl groups were introduced into the PFB with the substitution of PVA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45536.
Studying parental involvement and university access and choice: An ‘interacting multiple capitals’ model
Authors: Gao Fang , Ng Jacky Chi Kit
Published: July 2017

Capital‐embedded parental involvement in education is essential in enhancing university enrolment and maximising the educational potentials for equality and excellence. Previous studies in this field have mainly utilised Perna's (, ) model, which defines parental involvement as social capital and identifies the additive influences of different types of capital (including social, economic and cultural capital) on university access and choice. Yet, little research to date theorises and disaggregates the interplay among various types of capital as well as the multiplicative capital effects on enrolment. This study addressed this gap. We proposed an ‘interacting multiple capitals’ (IMC) model and hypothesised that parental social capital could moderate the effects of cultural and economic capital on entry to university. To validate the model, a pilot survey was administered to 216 university students of Korean ethnicity in China and investigated the models of involvement adopted by Korean parents in the context of the increasing labour mobility of the Korean adult population. Moderated multiple regression analysis was employed and the results confirmed the hypothesis that capital effects upon university access and choice were multiplicative in nature, with social capital moderating the cultural capital influence on students’ educational aspirations. The study findings show that the interaction of various types of capital variables is sufficiently statistically significant to warrant future research and policy and practical discussion of how to promote parental involvement in university preparation and planning.
Exceptionalism is not exceptional in relation to sexual and reproduction mechanisms: Contrasts of human and animal sexuality
Authors: Levin Roy J.
Published: July 2017

Speculation that the release of oxytocin by orgasm in the human female during coitus facilitates fertility by enhancing uterine sperm transport has been criticized as having no unequivocal empirical human evidence. However, a counter claim that this supports human “exceptionalism” as some form of uterine sperm transport occurs in other species. This is a misconception as it ignores that human uterine peristalsis, powered by contractions of the smooth muscle of the archimyometrium, facilitates sperm transport even without any systemic oxytocin involvement. Moreover, examination of various unique reproductive mechanisms in numerous animals also indicates that the claim is misjudged and rests on a biased interpretation of what “exceptionalism” means in this biological context. Ten chosen aspects of our sexuality are presented as being exceptional to humans. Clin. Anat. 30:940–945, 2017. © 2017 Wiley Periodicals, Inc.
Euler algorithm to solve reaction kinetic equations: Mathematical formulation, programing, and applications
Authors: Coto Baudilio , Suárez Inmaculada
Published: July 2017

Integration of rate laws to obtain the several concentrations in terms of time is well described in books of General Chemistry, Physical Chemistry, or Chemical Engineering including mathematical and graphical descriptions. When several reactions have to be considered simultaneously, the mathematical solution of involved differential equations became difficult for students and is a good task from the mathematical point of view. Qualitative interpretation has interest from the chemical and engineering point of view and it is usually related with the change of concentrations along reactions which in turns modifies the rate of the several processes involved. In this work, no differential equations are solved analytically and no functions are obtained in order to reduce the mathematical complexity for students but a numerical solution is obtained by using the differential method and the computation of changes in concentration. A general formulation of the involved equations is presented including the effect of reactant concentration in the rate laws and an arbitrary number of simultaneous reactions. Details for numerical solution of involved equations are indicated and the task for students is to create their own program to solve the rate laws. Student should be able to input a set of compounds and reactions, to compute the evolution of concentrations of the several species with time and to plot such concentrations. Some applications with increasing complexity were computed and analyzed. In order to show the quantitative obtained results, comparison with analytical functions was carried out for simple systems.
Comparison of local versus general anesthesia in patients undergoing transcatheter aortic valve replacement: A meta‐analysis
Authors: Villablanca Pedro A. , Mohananey Divyanshu , Nikolic Katarina , Bangalore Sripal , Slovut David P. , Mathew Verghese , Thourani Vinod H. , Rode's‐Cabau Josep , Núñez‐Gil Iván J. , Shah Tina , Gupta Tanush , Briceno David F. , Garcia Mario J. , Gutsche Jacob T. , Augoustides John G. , Ramakrishna Harish
Published: July 2017

Background

Transcatheter aortic valve replacement (TAVR) is typically performed under general anesthesia (GA). However, there is increasing data supporting the safety of performing TAVR under local anesthesia/conscious sedation (LA). We performed a meta‐analysis to gain better understanding of the safety and efficacy of LA versus GA in patients with severe aortic stenosis undergoing TAVR.

Methods and Results

We comprehensively searched EMBASE, PubMed, and Web of Science. Effect sizes were summarized using risk ratios (RRs) difference of the mean (DM), and 95% CIs (confidence intervals) for dichotomous and continuous variables respectively. Twenty‐six studies and 10,572 patients were included in the meta‐analysis. The use of LA for TAVR was associated with lower overall 30‐day mortality (RR, 0.73; 95% CI, 0.57–0.93; P = 0.01), use of inotropic/vasopressor drugs (RR, 0.45; 95% CI, 0.28–0.72; P < 0.001), hospital length of stay (LOS) (DM, −2.09; 95% CI, −3.02 to −1.16; P < 0.001), intensive care unit LOS (DM, −0.18; 95% CI, −0.31 to −0.04; P = 0.01), procedure time (DM, −25.02; 95% CI, −32.70 to −17.35; P < 0.001); and fluoroscopy time (DM, −1.63; 95% CI, −3.02 to −0.24; P = 0.02). No differences were observed between LA and GA for stroke, cardiovascular mortality, myocardial infarction, permanent pacemaker implantation, acute kidney injury, paravalvular leak, vascular complications, major bleeding, procedural success, conduction abnormalities, and annular rupture.

Conclusion

Our meta‐analysis suggests that use of LA for TAVR is associated with a lower 30‐day mortality, shorter procedure time, fluoroscopy time, ICU LOS, hospital length of stay, and reduced need for inotropic support.
Nitrogen‐Doped Graphene with a Three‐Dimensional Architecture Assisted by Carbon Nitride Tetrapods as an Efficient Metal‐Free Electrocatalyst for Hydrogen Evolution
Authors: Gangadharan Pranav K. , Unni Sreekuttan M. , Kumar Nandha , Ghosh Prasenjit , Kurungot Sreekumar
Published: July 2017

Current polymer membrane‐based electrolyzers use Pt as a cathode catalyst for efficient reduction of water. The high cost of Pt‐based catalysts forces researchers to develop alternative electrocatalysts. Here, a simple strategy has been proposed to synthesize a metal‐free electrocatalyst for the hydrogen evolution reaction (HER) by high‐temperature annealing of graphene oxide‐coated melamine foam. The prepared catalyst possesses both structural and functional advantages with its three‐dimensional (3D) interconnected arms of carbon nitride (CNx) backbone wrapped with nitrogen‐doped graphene (N‐RGO) sheets (CNx@N‐RGO). CNx@N‐RGO faces only a 193 mV overpotential to achieve a current density of 10 mA cm−2, which is far superior to the previously reported Pt‐free systems. Along with the high exchange current density 34.7×10−6 A cm−2 and low Tafel slope of 54 mV dec−1, CNx@N‐RGO follows a Volmer‐Heyrovsky mechanism for the HER. DFT calculations show that the synergy between CNx and N‐RGO facilitates good electrical coupling between the two moieties and provides optimal binding to H+ ions on the catalyst that, in turn, results in efficient reduction of hydrogen ions.
Non‐Covalent Assembly Method that Simultaneously Endows a Liposome Surface with Targeting Ligands, Protective PEG Chains, and Deep‐Red Fluorescence Reporter Groups
Authors: Shaw Scott K. , Liu Wenqi , Brennan Seamus P. , de Lourdes Betancourt‐Mendiola María , Smith Bradley D.
Published: July 2017

A new self‐assembly method is used to rapidly functionalize the surface of liposomes without perturbing the membrane integrity or causing leakage of the aqueous contents. The key molecule is a cholesterol‐squaraine‐PEG conjugate with three important structural elements: a cholesterol membrane anchor, a fluorescent squaraine docking station that allows rapid and high‐affinity macrocycle threading, and a long PEG‐2000 chain to provide steric shielding of the decorated liposome. The two‐step method involves spontaneous insertion of the conjugate into the outer leaflet of pre‐formed liposomes followed by squaraine threading with a tetralactam macrocycle that has appended targeting ligands. A macrocycle with six carboxylates permitted immobilization of intact fluorescent liposomes on the surface of cationic polymer beads, whereas a macrocycle with six zinc(II)‐dipicolylamine units enabled selective targeting of anionic membranes, including agglutination of bacteria in the presence of human cells.
PBPK Modeling of the Effect of Reduced Kidney Function on the Pharmacokinetics of Drugs Excreted Renally by Organic Anion Transporters
Authors: Hsueh C‐H , Hsu V , Zhao P , Zhang L , Giacomini KM , Huang S‐M
Published: July 2017

Altered pharmacokinetics (PK) in subjects with chronic kidney disease (CKD) may lead to dosing adjustment of certain drugs in subjects with CKD. It can be valuable to quantitatively predict PK in CKD for the management of drug dosing in these subjects. We developed physiologically based pharmacokinetic (PBPK) models of seven renally eliminated drugs: adefovir, avibactam, entecavir, famotidine, ganciclovir, oseltamivir carboxylate, and sitagliptin. These drugs are all substrates of renal organic anion transporters (OATs). Drug models verified using PK data from healthy subjects (HS) were coupled with physiological models representing CKD that incorporated prior knowledge of effects of CKD on hepatic and renal elimination. The models reasonably described clinically observed PK changes in subjects with CKD (compared to subjects with normal renal function), with predicted AUC changes within 50% of the observed changes. PBPK models can be used to prospectively predict PK of renally eliminated OAT substrates in subjects with CKD.
Structural Infrared Analysis of Ultra Nanosized Crystals of Yttria‐Stabilized Zirconia
Authors: Miao Baoji , Zhang Meng , Shen Jianhong , Stuerga Didier
Published: July 2017

This paper describes the characterization of ultra nanosized crystals as monoclinic, tetragonal, cubic or mixed phases of ZrO2. Nanopowders are produced using the microwave method, which allows control of the ratio of zirconium to yttrium to yield various crystallographic structures. The synthesized ultra nanosized particles have very broad XRD peaks. In particular, the similarity of the XRD peaks of tetragonal and cubic nanocrystals makes it difficult to distinguish between these two crystals. In this paper, tetragonal and cubic nanocrystals were clearly distinguished using infrared spectroscopy (IR). An infrared spectroscopic method to quantitatively analyse the percentage distribution between the two crystal phases was proposed. The results showed that pure zirconium dioxide was composed of 60 % monoclinic and 40 % tetragonal phases, while 8 % yttria‐stabilized zirconia (YSZ) contained 50 % tetragonal and 50 % cubic phases, and 14 % YSZ contained 100 % cubic phase.