bluuebunny/crossref_metadata_2025 huggingface dataset:
Fingerprints of Sea Level Rise on Changing Tides in the Chesapeake and Delaware Bays
Authors: Ross Andrew C. , Najjar Raymond G. , Li Ming , Lee Serena Blyth , Zhang Fan , Liu Wei
Published: September 2017

Secular tidal trends are present in many tide gauge records, but their causes are often unclear. This study examines trends in tides over the last century in the Chesapeake and Delaware Bays. Statistical models show negative M2 amplitude trends at the mouths of both bays, while some upstream locations have insignificant or positive trends. To determine whether sea level rise is responsible for these trends, we include a term for mean sea level in the statistical models and compare the results with predictions from numerical and analytical models. The observed and predicted sensitivities of M2 amplitude and phase to mean sea level are similar, although the numerical model amplitude is less sensitive to sea level. The sensitivity occurs as a result of strengthening and shifting of the amphidromic system in the Chesapeake Bay and decreasing frictional effects and increasing convergence in the Delaware Bay. After accounting for the effect of sea level, significant negative background M2 and S2 amplitude trends are present; these trends may be related to other factors such as dredging, tide gauge errors, or river discharge. Projected changes in tidal amplitudes due to sea level rise over the 21st century are substantial in some areas, but depend significantly on modeling assumptions.
Effects of the Relaxation of Upwelling‐Favorable Winds on the Diurnal and Semidiurnal Water Temperature Fluctuations in the Santa Barbara Channel, California
Authors: Aristizábal María F. , Fewings Melanie R. , Washburn Libe
Published: September 2017

In the Santa Barbara Channel, California, and around the Northern Channel Islands, water temperature fluctuations in the diurnal and semidiurnal frequency bands are intermittent, with amplitudes that vary on time scales of days to weeks. The cause of this intermittency is not well understood. We studied the effects of the barotropic tide, vertical stratification, propagation of coastal‐trapped waves, regional wind relaxations, and diurnal‐band winds on the intermittency of the temperature fluctuations during 1992–2015. We used temperature data from 43 moorings in 10–200 m water depth and wind data from two buoys and one land station. Subtidal‐frequency changes in vertical stratification explain 20–40% of the intermittency in diurnal and semidiurnal temperature fluctuations at time scales of days to weeks. Along the mainland north of Point Conception and at the Northern Channel Islands, the relaxation of upwelling‐favorable winds substantially increases vertical stratification, accounting for up to 55% of the subtidal‐frequency variability in stratification. As a result of the enhanced stratification, wind relaxations enhance the diurnal and semidiurnal temperature fluctuations at those sites, even though the diurnal‐band wind forcing decreases during wind relaxation. A linear model where the background stratification is advected vertically explains a substantial fraction of the temperature fluctuations at most sites. The increase of vertical stratification and subsequent increase in diurnal and semidiurnal temperature fluctuations during wind relaxation is a mechanism that can supply nutrients to the euphotic zone and kelp forests in the Channel in summer when upwelling is weak.
Hydrological Drought in the Anthropocene: Impacts of Local Water Extraction and Reservoir Regulation in the U.S.
Authors: Wan Wenhua , Zhao Jianshi , Li Hong‐Yi , Mishra Ashok , Ruby Leung L. , Hejazi Mohamad , Wang Wei , Lu Hui , Deng Zhiqun , Demissisie Yonas , Wang Hao
Published: September 2017

Key Points

Modeling analysis of future hydrologic droughts over U.S. is provided

Relative contributions from climate change and water managements are quantified

Future hydrologic drought will be alleviated by reservoirs but intensified by local water extraction
Observed Covariations of Aerosol Optical Depth and Cloud Cover in Extratropical Cyclones
Authors: Naud Catherine M. , Posselt Derek J. , van den Heever Susan C.
Published: September 2017

Using NASA Moderate Resolution Imaging Spectroradiometer aerosol optical depth and total cloud cover retrievals, CloudSat‐CALIPSO cloud profiles, and a database of extratropical cyclones and frontal boundary locations, relationships between changes in aerosol optical depth and cloud cover in extratropical cyclones occurring over Northern Hemisphere oceans are examined. A reanalysis data set is used to constrain column water vapor and ascent strength in the cyclones in an attempt to distinguish their impact on cloud cover from the effect of changes in aerosol loading. The results suggest that high aerosol optical depth cyclones exhibit larger middle‐ and high‐level cloud cover than their low aerosol optical depth counterparts. However, the opposite behavior is found for low‐level cloud cover. These relationships are found to depend on the large‐scale environment, in particular the column water vapor and vertical motion. Despite the inability of the observations to provide a causal physical link between aerosol load and cloud cover, these results can help to constrain and evaluate model simulations.
New Insights Into Lithology Distribution Across the Moon
Authors: Wang Xianmin , Zhao Siyuan
Published: September 2017

Lithology distribution across the Moon is pivotal for understanding lunar evolution. However, so far, the distribution of lunar rock suites is still uncertain; as a result, many related core issues on lunar evolution have long been in dispute. This work reports on a new lithology distribution map across the Moon and discusses some critical issues of the lunar evolutionary process. The oxide abundances derived from Chang'E‐1 Interference Imaging Spectrometer imagery and the Th contents inferred by Lunar Prospector Gamma Ray and Neutron Spectrometer data are employed to generate the lithological map by using the decision tree C5.0 algorithm. The following conclusions are inferred from this new map. (1) Magnesian suite is widely distributed across the Feldspathic Highlands Terrane and in the periphery of the South Pole‐Aitken Terrane. Thus, the viewpoints have been validated that the early magnesian magmatism may be a global phenomenon and that KREEP basalt is not necessary for the petrogenesis of Mg‐rich rocks. Moreover, the regions of Dryden, Chaffee S, Theophilus, and Moscoviense are confirmed as magnesian suite exposures. (2) The observation that the Feldspathic Highlands Terrane has a higher Mg/(Mg + Fe) value than the maria is related to the flood of the Mg suite across the Feldspathic Highlands Terrane. (3) The specific exposed locations of the alkali suite across the Moon have long been unsolved, and this work discloses that the alkali suite prevails in the outskirts of the Procellarum KREEP Terrane, the center of the South Pole‐Aitken Terrane, and some isolated locales. (4) Focusing on distinguishing mare basalts from other mafic rocks, seven geochemical indices are proposed to determine the potential exposures of mare basalts across the Moon. (5) In Mare Insularum, a series of KREEP volcanisms may have occurred and lasted longer than the mare volcanism.
Influence of Sediment Cohesion on Deltaic Morphodynamics and Stratigraphy Over Basin‐Filling Time Scales
Authors: Li Qi , Matthew Benson W. , Harlan Margaret , Robichaux Patrick , Sha Xiaoyu , Xu Kehui , Straub Kyle M.
Published: September 2017

Results from physical and numerical experiments suggest that sediment cohesion influences deltaic morphodynamics by promoting the development and maintenance of channels. As a result, cohesion is thought to increase the magnitude and time scales of internally generated (autogenic) processes and the dimensions of their stratigraphic products. We test these hypotheses by examining the surface processes and stratigraphic products from a suite of physical experiments where the influence of cohesion is isolated over temporal and spatial scales important for basin filling. Given the stochastic nature of autogenic sediment transport processes, we develop and employ a range of statistical tools and metrics. We observe that (1) an increase in sediment cohesion decreases lateral channel mobility and thus increases the time necessary to regrade deltaic surfaces; (2) enhanced channelization, due to sediment cohesion, increases the time necessary for the deposits of autogenic processes to average together and produce stratigraphic products with shapes set by the generation of regional accommodation; (3) cohesion promotes the transport of suspended sediment to terrestrial overbank and marine environments, which decreases the volume of channel, relative to overbank and marine deposits in the stratigraphic record. This increase in overbank and marine deposition changes the spatial distribution of sand in stratigraphy, with higher cohesion linked to enhanced segregation of fine particles from coarse sand in the experimental deposits. Combined, these results illustrate how the cohesion of sediment is fundamental in setting autogenic spatial and temporal scales and needs to be considered when inverting stratigraphic architecture for paleo‐environmental history.
Use of a radial projection to reduce the statistical uncertainty of spot lateral profiles generated by Monte Carlo simulation
Authors: Ding Xiaoning , Liu Wei , Shen Jiajian , Anand Aman , Stoker Joshua B. , Hu Yanle , Bues Martin
Published: September 2017

Monte Carlo (MC) simulation has been used to generate commissioning data for the beam modeling of treatment planning system (TPS). We have developed a method called radial projection (RP) for postprocessing of MC‐simulation‐generated data. We used the RP method to reduce the statistical uncertainty of the lateral profile of proton pencil beams with axial symmetry. The RP method takes advantage of the axial symmetry of dose distribution to use the mean value of multiple independent scores as the representative score. Using the mean as the representative value rather than any individual score results in substantial reduction in statistical uncertainty. Herein, we present the concept and step‐by‐step implementation of the RP method, as well as show the advantage of the RP method over conventional measurement methods for generating lateral profile. Lateral profiles generated by both methods were compared to demonstrate the uncertainty reduction qualitatively, and standard error comparison was performed to demonstrate the reduction quantitatively. The comparisons showed that statistical uncertainty was reduced substantially by the RP method. Using the RP method to postprocess MC data, the corresponding MC simulation time was reduced by a factor of 10 without quality reduction in the generated result from the MC data. We concluded that the RP method is an effective technique to increase MC simulation efficiency for generating lateral profiles for axially symmetric pencil beams.
Multi‐Stable Mechanical Structural Materials
Authors: Wu Lingling , Xi Xiaoqing , Li Bo , Zhou Ji
Published: September 2017

Energy absorbing is an important and desirable property in mechanical and civil engineering. Here, a proof‐of‐concept method is presented as a new approach to achieve artificial mechanical materials with tunable compressive behavior for energy absorbing constructed from unit cells with a snap fit structure. The artificial structure undergoes a series of stable configurations derived from the sequential insertion of the plug into the groove of the snap fit. Both, experimental and simulation results manifest the multi‐stable and tunable mechanical properties of the structure. The mechanical energy dissipated by the proposed structure is demonstrated to be dependent on the lead‐in angle of the snap fit and the deflection ratio of the groove, as well as on the coefficient of friction between the plug and the groove of the snap fit. The system designed, herein, exhibits mechanical properties that can be tuned not only by adjusting the geometric parameters, but also by tuning the coefficient of friction between the plug and the groove, allowing the mechanical properties to be tailored post‐fabrication. Furthermore, the proposed model can be extended to the macro‐, micro‐, or nanoscales. These findings provide a simple method to obtain artificial materials with tunable energy absorbing properties, which can be applied in areas such as the design of automobile bumpers and foldable devices that facilitate their transportation.
Highly Conductive and Transparent Large‐Area Bilayer Graphene Realized by MoCl5 Intercalation
Authors: Kinoshita Hiroki , Jeon Il , Maruyama Mina , Kawahara Kenji , Terao Yuri , Ding Dong , Matsumoto Rika , Matsuo Yutaka , Okada Susumu , Ago Hiroki
Published: September 2017

Bilayer graphene (BLG) comprises a 2D nanospace sandwiched by two parallel graphene sheets that can be used to intercalate molecules or ions for attaining novel functionalities. However, intercalation is mostly demonstrated with small, exfoliated graphene flakes. This study demonstrates intercalation of molybdenum chloride (MoCl5) into a large‐area, uniform BLG sheet, which is grown by chemical vapor deposition (CVD). This study reveals that the degree of MoCl5 intercalation strongly depends on the stacking order of the graphene; twist‐stacked graphene shows a much higher degree of intercalation than AB‐stacked. Density functional theory calculations suggest that weak interlayer coupling in the twist‐stacked graphene contributes to the effective intercalation. By selectively synthesizing twist‐rich BLG films through control of the CVD conditions, low sheet resistance (83 Ω ▫−1) is realized after MoCl5 intercalation, while maintaining high optical transmittance (≈95%). The low sheet resistance state is relatively stable in air for more than three months. Furthermore, the intercalated BLG film is applied to organic solar cells, realizing a high power conversion efficiency.
Semiconducting Polymer Nanoparticles for Centimeters‐Deep Photoacoustic Imaging in the Second Near‐Infrared Window
Authors: Wu Jiayingzi , You Liyan , Lan Lu , Lee Hyeon Jeong , Chaudhry Saadia T. , Li Rui , Cheng Ji‐Xin , Mei Jianguo
Published: September 2017

Thienoisoindigo‐based semiconducting polymer with a strong near‐infrared absorbance is synthesized and its water‐dispersed nanoparticles (TSPNs) are investigated as a contrast agent for photoacoustic (PA) imaging in the second near‐infrared (NIR‐II) window (1000–1350 nm). The TSPNs generate a strong PA signal in the NIR‐II optical window, where background signals from endogenous contrast agents, including blood and lipid, are at the local minima. By embedding a TSPN‐containing tube in chicken‐breast tissue, an imaging depth of more than 5 cm at 1064 nm excitation is achieved with a contrast‐agent concentration as low as 40 µg mL−1. The TSPNs under the skin or in the tumor are clearly visualized at 1100 and 1300 nm, with negligible interference from the tissue background. TSPN as a PA contrast in the NIR‐II window opens new opportunities for biomedical imaging of deep tissues with improved contrast.
Hybrid Plasmonic Modes in Multilayer Trench Grating Structures
Authors: Liu Xiaoyi , Gao Jinsong , Yang Haigui , Wang Xiaoyi , Tian Sicong , Guo Chengli
Published: September 2017

For common plasmonic structures, it is difficult to considerate both the abilities of confining light and reducing loss. Here, two plasmonic multilayer structures comprised of five alternate Al and Si layers are demonstrated. First, the multilayer gratings with near‐infrared dual narrowband peaks are given in the spectrum excited by Fabry–Perot resonance. Through investigating the modes of electric field distributions, the frequency‐sensitivity, and linear designable characteristic of its working bands are clarified. Second, the multilayer trench gratings containing both stripes and trenches, which can induce the cavity effect additionally, are demonstrated. When the incidence is oblique, some new modes can be observed, leading to the C‐S hybrid plasmonic coupling modes. Besides, by changing the length of designed waveguide, the Fabry–Perot resonance modes can successively merge with the cavity effect modes, generating the hybrid modes regularly. As a contrast, their quality factors to evaluate the losses and qualities of designed two structures are calculated, and the results imply that the multilayer trench gratings reduce the loss effectively without decreasing energy localization. Detailed process and significance of calculations are discussed carefully.
Enzymatic Synthesis of Bufadienolide O‐Glycosides as Potent Antitumor Agents Using a Microbial Glycosyltransferase
Authors: Li Kai , Feng Jin , Kuang Yi , Song Wei , Zhang Meng , Ji Shuai , Qiao Xue , Ye Min
Published: September 2017

Bufadienolides are a class of natural cardiotonic steroids and are well known for their antitumor activities. Their clinical use has been hindered by poor water solubility. Enzymatic glycosylation is a favorable approach to improve the solubility of natural products. In this work, we describe the highly efficient one‐step synthesis of bufadienolide O‐glucosides and O‐galactosides using a microbial glycosyltransferase YjiC1, with conversion rates from 63% to 99%. Altogether 24 glycosides including 17 new compounds were obtained from 14 substrates, and their structures were identified by extensive NMR and high‐resolution electrospray ionization mass spectrometry (HR‐ESI‐MS) analyses. These products belong to five types: glycosylation at 3β‐OH, 7β‐OH, 3β,7β‐di‐OH, 11α‐OH, and 12β‐OH. The C‐7β or C‐11α O‐glycosides of bufadienolide are reported for the first time. Moreover, the 3‐O‐glycosides exhibited significant cytotoxic activities against A549 and MCF7 human cancer cell lines, and showed potent inhibitory activities against Na+/K+‐ATPase with IC50 values in the range 0.053–0.76 μM. In particular, bufalin 3‐O‐β‐d‐glucoside showed enhanced water solubility (25‐fold increase from bufalin) and potent antitumor activities (30% inhibition rate, 1.4 mg kg−1, i.p.) on A549 human lung cancer xenograft Balb/c nude mice model, and could be a promising drug candidate.

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Catalyst‐ and Oxidant‐Free Desulfonative C−P Couplings for the Synthesis of Phosphine Oxides and Phosphonates
Authors: Guo Hong‐Mei , Zhou Quan‐Quan , Jiang Xuan , Shi De‐Qing , Xiao Wen‐Jing
Published: September 2017

An efficient and practical approach towards phosphine oxides and phosphonates has been successfully developed through the desulfonative coupling of various sulfones with secondary phosphine oxides and phosphites. This protocol features simple experimental procedures under mild conditions (i. e., catalyst‐ and oxidant‐free, room temperature and open to air). By doing so, a variety of alkynyl, alkenyl and allyl phosphine oxides or phosphonates can be produced in generally good reaction efficiency and selectivity (31 examples, up to 98% yield).

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Rational Design of a Water‐Storable Hierarchical Architecture Decorated with Amorphous Barium Oxide and Nickel Nanoparticles as a Solid Oxide Fuel Cell Anode with Excellent Sulfur Tolerance
Authors: Song Yufei , Wang Wei , Ge Lei , Xu Xiaomin , Zhang Zhenbao , Julião Paulo Sérgio Barros , Zhou Wei , Shao Zongping
Published: September 2017

Solid oxide fuel cells (SOFCs), which can directly convert chemical energy stored in fuels into electric power, represent a useful technology for a more sustainable future. They are particularly attractive given that they can be easily integrated into the currently available fossil fuel infrastructure to realize an ideal clean energy system. However, the widespread use of the SOFC technology is hindered by sulfur poisoning at the anode caused by the sulfur impurities in fossil fuels. Therefore, improving the sulfur tolerance of the anode is critical for developing SOFCs for use with fossil fuels. Herein, a novel, highly active, sulfur‐tolerant anode for intermediate‐temperature SOFCs is prepared via a facile impregnation and limited reaction protocol. During synthesis, Ni nanoparticles, water‐storable BaZr0.4Ce0.4Y0.2O3−δ (BZCY) perovskite, and amorphous BaO are formed in situ and deposited on the surface of a Sm0.2Ce0.8O1.9 (SDC) scaffold. More specifically, a porous SDC scaffold is impregnated with a well‐designed proton‐conducting perovskite oxide liquid precursor with the nominal composition of Ba(Zr0.4Ce0.4Y0.2)0.8Ni0.2O3−δ (BZCYN), calcined and reduced in hydrogen. The as‐synthesized hierarchical architecture exhibits high H2 electro‐oxidation activity, excellent operational stability, superior sulfur tolerance, and good thermal cyclability. This work demonstrates the potential of combining nanocatalysts and water‐storable materials in advanced electrocatalysts for SOFCs.
UV‐Sensing Semitransparent Organic Field‐Effect Transistors with Wide Bandgap Small Molecular Channel and Polymeric Gate‐Insulating Layers
Authors: Lee Chulyeon , Lee Sooyong , Kim Hwajeong , Kim Youngkyoo
Published: September 2017

This study demonstrates UV‐sensing semitransparent organic field‐effect transistors (OFETs) with wide bandgap small molecular channel and polymeric gate‐insulating layers. N,N′‐di(1‐naphthyl)‐N,N′‐diphenyl‐(1,1′‐biphenyl)‐4,4′‐diamine (NPB) is employed as the wide bandgap channel layer, while poly(methyl methacrylate) is introduced as the wide bandgap gate‐insulating layer. The performance of OFETs is optimized by NPB thickness control and thermal treatment. Results show that the best device performance (on/off ratio = 4.7 × 106 and hole mobility = 4.2 × 10−5 cm2 V−1 s−1) is achieved by thermal treatment of the 130 nm thick NPB layers at 70 °C for 30 min leading to a noticeably changed surface morphology in the NPB layers. The optimized OFETs exhibit excellent operation stability without hysteresis, while those with semitransparent silver electrodes deliver quite a good transparency. The semitransparent OFETs can sensitively detect a UV light with high stability even though no photoresponse is measured under a visible light.
Improved Performance in n‐Type Organic Field‐Effect Transistors via Polyelectrolyte‐Mediated Interfacial Doping
Authors: Park Yu Jung , Cha Myoung Joo , Yoon Yung Jin , Cho Shinuk , Kim Jin Young , Seo Jung Hwa , Walker Bright
Published: September 2017

To enhance electron injection in n‐type organic field‐effect transistors (OFETs), nonconjugated polyelectrolyte (NPE) layers are interposed between a [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) layer and Au electrodes. A series of NPEs based on an ethoxylated polyethylenimine backbone with various counterions, including Cl−, Br−, and I−, improve electron mobilities up to ≈10−2 cm2 V−1 s−1 and yield on–off ratios (Ion/Ioff) of 105 in PCBM OFETs. Ultraviolet photoelectron spectroscopy reveals that all of the NPEs lead to reduced electron injection barriers (φe) at the NPE/metal interface; this reduction in φe is consistent with dipole formation or n‐type doping at the electrode interface. Absorption measurements of PCBM films treated with NPEs are consistent with n‐doping of the PCBM. Regardless of the type of anion, thick NPE layers lead to high conductivity in the films independent of gate bias, whereas thin NPE layers lead to dramatically improved electron injection and performance. These results demonstrate that thin polyelectrolyte layers can be used to achieve controlled interfacial doping in organic semiconductors. Furthermore, this study provides valuable information about the function of NPEs, which may be exploited to improve device performance and to design new materials for future use in optoelectronic devices.
Near‐Infrared, Heavy Metal‐Free Colloidal “Giant” Core/Shell Quantum Dots
Authors: Tong Xin , Kong Xiang‐Tian , Zhou Yufeng , Navarro‐Pardo Fabiola , Selopal Gurpreet Singh , Sun Shuhui , Govorov Alexander O. , Zhao Haiguang , Wang Zhiming M. , Rosei Federico
Published: September 2017

“Giant” core/shell quantum dots (g‐QDs) are a promising class of materials for future optoelectronic technologies due to their superior chemical‐ and photostability compared to bare QDs and core/thin shell QDs. However, inadequate light absorption in the visible and near‐infrared (NIR) region and frequent use of toxic heavy metals (e.g., Cd and Pb) are still major challenges for most g‐QDs (e.g., CdSe/CdS) synthesized to date. The synthesis of NIR, heavy metal‐free, Zn‐treated spherical CuInSe2/CuInS2 g‐QDs is reported using the sequential cation exchange method. These g‐QDs exhibit tunable NIR optical absorption and photoluminescence (PL) properties. Transient fluorescence spectroscopy shows prolonged lifetime with increasing shell thickness, indicating the formation of quasi type‐II band alignment, which is further confirmed by simulations. As a proof‐of‐concept, as‐synthesized g‐QDs are used to sensitize TiO2 as a photoanode in a photoelectrochemical (PEC) cell, demonstrating an efficient and stable PEC system. These results pave the way toward synthesizing NIR heavy metal‐free g‐QDs, which are very promising components of future optoelectronic technologies.
An Omnidirectionally Stretchable Piezoelectric Nanogenerator Based on Hybrid Nanofibers and Carbon Electrodes for Multimodal Straining and Human Kinematics Energy Harvesting
Authors: Siddiqui Saqib , Lee Han Byeol , Kim Do‐Il , Duy Le Thai , Hanif Adeela , Lee Nae‐Eung
Published: September 2017

Stretchable piezoelectric nanogenerators (SPENGs) for human kinematics energy harvesting have limited use due to the low stretchability or mechanical robustness and the difficulty of structural design for omnidirectional stretchability. This study reports an efficient, omnidirectionally stretchable, and robust SPENG based on a stretchable graphite electrode on a 3D micropatterned stretchable substrate and a stacked mat of piezoelectric nanofibers. The stacked mat of free‐standing nanofibers is alternatively composed of nanocomposite nanofibers of barium titanate nanoparticles embedded in polyurethane and poly(vinylidene fluoride‐trifluoroethylene) nanofibers. The nanofiber SPENG (nf‐SPENG) exhibits a high stretchability of 40% and high mechanical durability up to 9000 stretching cycles at 30% strain, which are attributed to the stress‐relieving nature of the 3D micropattern on the substrate and the free‐standing stacked hybrid nanofibers. The nf‐SPENG produces a peak open circuit voltage (Voc) and short circuit current (Isc) of 9.3 V and 189 nA, respectively. The nf‐SPENG is demonstrated to harvest the energy from human kinematics while walking when placed over the knee cap of a subject, generating a maximum Voc of 10.1 V. The omnidirectional stretchability, efficiency, facile fabrication process, mechanical durability, environmentally friendly lead‐free components, and response to multimodal straining make this device suitable for self‐powered wearable sensing systems.
Doped Copper Phthalocyanine via an Aqueous Solution Process for Normal and Inverted Perovskite Solar Cells
Authors: Wang Jin‐Miao , Wang Zhao‐Kui , Li Meng , Zhang Cong‐Cong , Jiang Lu‐Lu , Hu Ke‐Hao , Ye Qing‐Qing , Liao Liang‐Sheng
Published: September 2017

Great efforts toward developing novel and efficient hole‐transporting materials are needed to further improve the device efficiency and enhance the cell stability of perovskite solar cells (PSCs). The poor film conductivity and the low carrier mobility of organic small‐molecule‐based hole‐transporting materials restrict their application in PSCs. This study develops an efficient and stable hole‐transporting material, tetrafluorotetracyanoquinodimethane (F4‐TCNQ)‐doped copper phthalocyanine‐3,4′,4′′,4′′′‐tetra‐sulfonated acid tetra sodium salt (TS‐CuPc) via a solution process, in planar structure PSCs. The p‐type‐doped TS‐CuPc film demonstrates improved film conductivity and hole mobility owing to the strong electron affinity of F4‐TCNQ. By the F4‐TCNQ tailoring, the composite film gives the highest occupied molecular orbital level as high as 5.3 eV, which is beneficial for hole extraction. In addition, the aqueous solution processed TS‐CuPc:F4‐TCNQ precursor is almost neutral with good stability for avoiding the electrode erosion. As a result, the fabricated PSCs employing TS‐CuPc:F4‐TCNQ as the hole‐transporting material exhibit a power conversion efficiency of 16.14% in a p–i–n structure and 20.16% in an n–i–p structure, respectively. The developed organic small molecule of TS‐CuPc provides the diversification of hole‐transporting materials in planar PSCs.
Polymer Doping for High‐Efficiency Perovskite Solar Cells with Improved Moisture Stability
Authors: Jiang Jiexuan , Wang Qian , Jin Zhiwen , Zhang Xisheng , Lei Jie , Bin Haijun , Zhang Zhi‐Guo , Li Yongfang , Liu Shengzhong (Frank)
Published: September 2017

Each component layer in a perovskite solar cell plays an important role in the cell performance. Here, a few types of polymers including representative p‐type and n‐type semiconductors, and a classical insulator, are chosen to dope into a perovskite film. The long‐chain polymer helps to form a network among the perovskite crystalline grains, as witnessed by the improved film morphology and device stability. The dewetting process is greatly suppressed by the cross‐linking effect of the polymer chains, thereby resulting in uniform perovskite films with large grain sizes. Moreover, it is found that the polymer‐doped perovskite shows a reduced trap‐state density, likely due to the polymer effectively passivating the perovskite grain surface. Meanwhile the doped polymer formed a bridge between grains for efficient charge transport. Using this approach, the solar cell efficiency is improved from 17.43% to as high as 19.19%, with a much improved stability. As it is not required for the polymer to have a strict energy level matching with the perovskite, in principle, one may use a variety of polymers for this type of device design.
Ru(bpy)3Cl2 as a Photocatalyst for Visible‐Light‐Induced Fluoroalkylation of Anilines with BrCF2CF2Br: A Facile Route to 2‐Bromo‐1,1,2,2‐tetrafluoroethyl Arenes
Authors: Kong Jingjing , Jiang Jianfang , Huang Yang , Lou Yue‐Guang , Li Xiao‐Fei , He Chun‐Yang
Published: September 2017

A convenient method for the preparation of 2‐bromo‐1,1,2,2‐tetrafluoroethyl arenes, using commercially available anilines and BrCF2CF2Br as starting materials was developed. The reaction proceeded in high efficiency under the irradiation of blue LEDs, and enables the installation of amino and fluoroalkyl moieties. Moreover, the product can be easily transformed to many other 1,1,2,2‐tetrafluoroethylated reagents, thus demonstrating its high potential use for further modifications.
Development of the Japanese version of the Preschool Confusion Assessment Method for the ICU
Authors: Matsuishi Yujiro , Hoshino Haruhiko , Shimojo Nobutake , Enomoto Yuki , Kido Takahiro , Jesmin Subrina , Sumitani Masahiko , Inoue Yoshiaki
Published: September 2017

Aim

Delirium is associated with various negative clinical outcomes, such as decline in cognitive ability, increased length of hospital stay, and higher mortality. For these reasons, early diagnosis of delirium is critical. Unfortunately, there are no reliable diagnostic criteria or tool of delirium for infants and preschool‐aged children in Japan.

The aim of the present study was to translate a new delirium assessment tool, the Preschool Confusion Assessment Method for the Intensive Care Unit (psCAM‐ICU), for accurately diagnosing clinically ill infants and preschool‐aged children, from English to Japanese.

Methods

The translation was undertaken with the internationally established back‐translation method. The translation was repeated blindly and independently by eight medical researchers and clinicians from multiple disciplines. Any discrepancy evident from the translated works was discussed and resolved.

Results

We report the successful development of the Japanese version of psCAM‐ICU. However, before its full application, this diagnostic tool requires further testing and study, most notably for its validation and reliability.

Conclusion

A Japanese version of the psCAM‐ICU was developed.
A Space‐Charge Treatment of the Increased Concentration of Reactive Species at the Surface of a Ceria Solid Solution
Authors: Zurhelle Alexander F. , Tong Xiaorui , Klein Andreas , Mebane David S. , De Souza Roger A.
Published: September 2017

A space‐charge theory applicable to concentrated solid solutions (Poisson–Cahn theory) was applied to describe quantitatively as a function of temperature and oxygen partial pressure published data obtained by in situ X‐ray photoelectron spectroscopy (XPS) for the concentration of Ce3+ (the reactive species) at the surface of the oxide catalyst Ce0.8Sm0.2O1.9. In contrast to previous theoretical treatments, these calculations clearly indicate that the surface is positively charged and compensated by an attendant negative space‐charge zone. The high space‐charge potential that develops at the surface (>0.8 V) is demonstrated to be hardly detectable by XPS measurements because of the short extent of the space‐charge layer. This approach emphasizes the need to take into account defect interactions and to allow deviations from local charge neutrality when considering the surfaces of oxide catalysts.
Borane‐Stabilized Isomeric Dimers of the Phosphaethynolate Anion
Authors: Szkop Kevin M. , Jupp Andrew R. , Suter Riccardo , Grützmacher Hansjörg , Stephan Douglas W.
Published: September 2017

The reactions of the phosphaethynolate anion ([PCO]−) with a range of boranes were explored. BPh3 and [PCO]− form a dimeric anion featuring P−B bonds and is prone to dissociation at room temperature. The more Lewis acidic borane B(C6F5)3 yields a less symmetric dimer of [PCO]− with P−B and P−O bonds. Less sterically demanding HB(C6F5)2 and H2B(C6F5) boranes form a third isomer with [PCO]− featuring both boranes bound to the same phosphorus atom. Despite the unexpected thermodynamic preference for P‐coordination, computational data illustrate that electronic and steric features impact the binding modes of the resulting dianionic dimers.
Chemomechanical, morphological, and rheological studies of chitosan‐graft‐lactic acid oligomer reinforced poly(lactic acid) bionanocomposite films
Authors: Pal Akhilesh Kumar , Bhattacharjee Sayan Kumar , Gaur Surendra Singh , Pal Ajinkya , Katiyar Vimal
Published: September 2017

Various compositions of nontoxic biodegradable poly(lactic acid) (PLA)/chitosan‐graft‐lactic acid oligomer (CH‐g‐OLLA) bionanocomposite films were fabricated with a solution casting technique by the dispersal of CH‐g‐OLLA copolymer at different amounts (1, 3, and 5 wt %) into the PLA matrix. The filler (CH‐g‐OLLA) was synthesized by an in situ condensation polymerization reaction in a microwave, and the grafting of lactic acid oligomer chains at the C2 position of the chitosan backbone was confirmed by the presence of new peaks at 179.08 and 174.41 ppm in 13C‐NMR analysis. The transparency results show the synergic effect of CH‐g‐OLLA in the form of reduced transparency and excellent blocking capability of UV light. Dynamic mechanical analysis confirmed a reduction in the glass‐transition temperature (up to ∼13 °C) with increasing filler concentration; this signified the improvement in the elongation of bionanocomposite films. The rheological studies showed the viscous behavior of the PLA and PLA–CH‐g‐OLLA bionanocomposite films as the storage modulus values were found to be lower than the loss modulus values over the entire range of angular frequency at 180 °C. Furthermore, a Cole–Cole plot and Han plot described the uniform dispersion of the filler in the PLA matrix, its agglomeration at higher loading, and the structural change between the PLA and PLA–CH‐g‐OLLA bionanocomposite films. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45546.
Inhibition of Vascular Endothelial Growth Factor Receptor Decreases Regenerative Angiogenesis in Axolotls
Authors: Ritenour Angela M. , Dickie Renee
Published: September 2017

Angiogenesis is crucial for tissue growth and repair in mammals, and is chiefly regulated by vascular endothelial growth factor (VEGF) signaling. We evaluated the effect of chemical inhibition of VEGF receptor signaling in animals with superior regenerative ability, axolotl salamanders, to determine the impact on vascularization and regenerative outgrowth. Following tail amputation, treated animals (100 nM PTK787) and controls were examined microscopically and measured over the month‐long period of regeneration. Treatment with VEGFR inhibitor decreased regenerative angiogenesis; drug‐treated animals had lower vascular densities in the regenerating tail than untreated animals. This decrease in neovascularization, however, was not associated with a decrease in regenerative outgrowth or with morphological abnormalities in the regrown tail. Avascular but otherwise anatomically normal regenerative outgrowth over 1 mm beyond the amputation plane was observed. The results suggest that in this highly regenerative species, significant early tissue regeneration is possible in the absence of a well‐developed vasculature. This research sets the groundwork for establishing a system for the chemical manipulation of angiogenesis within the highly regenerative axolotl model, contributing to a better understanding of the role of the microvasculature within strongly proliferative yet well‐regulated environments. Anat Rec, 300:2273–2280, 2017. © 2017 Wiley Periodicals, Inc.
Structural insight into the XTACC3/XMAP215 interaction from CD and NMR studies on model peptides
Authors: Partida‐Hanon Angélica , Treviño Miguel A. , Mompeán Miguel , Jiménez Ma Ángeles , Bruix Marta
Published: September 2017

TACC3 is a centrosomal adaptor protein that plays important roles during mitotic spindle assembly. It interacts with chTOG/XMAP215, which catalyzes the addition of tubulin dimers during microtubule growth. A 3D coiled‐coil model for this interaction is available but the structural details are not well described. To characterize this interaction at atomic resolution, we have designed a simplified version of the system based on small peptides. Four different peptides have been studied by circular dichroism and nuclear magnetic resonance both singly and in all possible combinations; namely, five peptide pairs and two trios. In cosolvents, all single peptides tend to adopt helical conformations resembling those of the full‐length protein. However, neither the single peptides nor pairs of peptides form coiled coils. We show that the simultaneous presence of all preformed helices is a prerequisite for binding. The simplest 3D model for the interaction, based on the NMR results, is proposed. Interestingly, the peptide's structure remains unaffected by mutations at essential positions for TACC3 activity. This suggests that the lack of interaction of this TACC3 mutant with XMAP does not correlate with changes in the protein structure and that specific interactions are likely responsible for the interaction and stability of the complex.
Imaging stem cell distribution, growth, migration, and differentiation in 3‐D scaffolds for bone tissue engineering using mesoscopic fluorescence tomography
Authors: Tang Qinggong , Piard Charlotte , Lin Jonathan , Nan Kai , Guo Ting , Caccamese John , Fisher John , Chen Yu
Published: September 2017

Regenerative medicine has emerged as an important discipline that aims to repair injury or replace damaged tissues or organs by introducing living cells or functioning tissues. Successful regenerative medicine strategies will likely depend upon a simultaneous optimization strategy for the design of biomaterials, cell‐seeding methods, cell‐biomaterial interactions, and molecular signaling within the engineered tissues. It remains a challenge to image three‐dimensional (3‐D) structures and functions of the cell‐seeded scaffold in mesoscopic scale (>2 ∼ 3 mm). In this study, we utilized angled fluorescence laminar optical tomography (aFLOT), which allows depth‐resolved molecular characterization of engineered tissues in 3‐D to investigate cell viability, migration, and bone mineralization within bone tissue engineering scaffolds in situ.
Karyotype variation of CHO host cell lines over time in culture characterized by chromosome counting and chromosome painting
Authors: Vcelar Sabine , Jadhav Vaibhav , Melcher Michael , Auer Norbert , Hrdina Astrid , Sagmeister Rebecca , Heffner Kelley , Puklowski Anja , Betenbaugh Michael , Wenger Till , Leisch Friedrich , Baumann Martina , Borth Nicole
Published: September 2017

Genomic rearrangements are a common phenomenon in rapidly growing cell lines such as Chinese hamster ovary (CHO) cells, a feature that in the context of production of biologics may lead to cell line and product instability. Few methods exist to assess such genome wide instability. Here, we use the population distribution of chromosome numbers per cell as well as chromosome painting to quantify the karyotypic variation in several CHO host cell lines. CHO‐S, CHO‐K1 8 mM glutamine, and CHO‐K1 cells adapted to grow in media containing no glutamine were analyzed over up to 6 months in culture. All three cell lines were clearly distinguishable by their chromosome number distribution and by the specific chromosome rearrangements that were present in each population. Chromosome Painting revealed a predominant karyotype for each cell line at the start of the experiment, completed by a large number of variants present in each population. Over time in culture, the predominant karyotype changed for CHO‐S and CHO‐K1, with the diversity increasing and new variants appearing, while CHO‐K1 0 mM Gln preferred chromosome pattern increased in percent of the population over time. As control, Chinese hamster lung fibroblasts were shown to also contain an increasing number of variants over time in culture.
Exploring cellular behavior under transient gene expression and its impact on mAb productivity and Fc‐glycosylation
Authors: Sou Si N. , Lee Ken , Nayyar Kalpana , Polizzi Karen M. , Sellick Christopher , Kontoravdi Cleo
Published: September 2017

Transient gene expression (TGE) is a methodology employed in bioprocessing for the fast provision of recombinant protein material. Mild hypothermia is often introduced to overcome the low yield typically achieved with TGE and improve specific protein productivity. It is therefore of interest to examine the impact of mild hypothermic temperatures on both the yield and quality of transiently expressed proteins and the relationship to changes in cellular processes and metabolism. In this study, we focus on the ability of a Chinese hamster ovary cell line to galactosylate a recombinant monoclonal antibody (mAb) product. Through experimentation and flux balance analysis, our results show that TGE in mild hypothermic conditions led to a 76% increase in qP compared to TGE at 36.5°C in our system. This increase is accompanied by increased consumption of nutrients and amino acids, together with increased production of intracellular nucleotide sugar species, and higher rates of mAb galactosylation, despite a reduced rate of cell growth. The reduction in biomass accumulation allowed cells to redistribute their energy and resources toward mAb synthesis and Fc‐glycosylation. Interestingly, the higher capacity of cells to galactosylate the recombinant product in TGE at 32°C appears not to have been assisted by the upregulation of galactosyltransferases (GalTs), but by the increased expression of N‐acetylglucosaminyltransferase II (GnTII) in this cell line, which facilitated the production of bi‐antennary glycan structures for further processing.
Capturing CO2 by Using a Microalgae Culture Recycle Solution
Authors: Chen Pao-Chi , Chou Po-Han , Lin Sheng-Zhong , Chen Hsiao-Wei
Published: September 2017

The capture of CO2 by means of a microalgae culture solution was explored in a continuous bubble‐column scrubber under a constant pH environment. Optimum conditions for a pilot‐scale study were evaluated. With the Taguchi method, a total of sixteen runs were required. Absorption rate, absorption efficiency, overall mass transfer coefficient, and gas‐liquid flow rate ratio were determined by a material balance model and a two‐film model under steady‐state conditions. From the signal‐to‐noise ratio, the sequence of parameters could be stated. Uncontrolled experiments were also performed and empirical equations were discussed.
3D‐Printed Electrodes with Improved Mass Transport Properties
Authors: Lölsberg Jonas , Starck Ottokar , Stiefel Serafin , Hereijgers Jonas , Breugelmans Tom , Wessling Matthias
Published: September 2017

Today's electrochemical reactor design is a less developed discipline as compared to electrocatalytic synthesis. Although catalysts show increasing conversion rates, they are often operated without measures for the reduction of concentration polarization effects. As a result, a stagnant boundary layer forms at the electrode‐electrolyte interface. This stagnant boundary layer presents an additional voltage drop and reduces the energy efficiency. It is generally accepted that this phenomenon is caused by a combination of fast electrode reactions and slow diffusion of the reacting species. Our earlier work demonstrated the potential of non‐conducting static mixers to reduce concentration polarization effects. However, there are few studies on conductive static mixers applied as electrodes. In this study, we present a new concept of additive manufactured flow through electrode mixers. Our electrode geometry combines a high surface area with mixing properties, diminishing concentration polarization effects of transport‐limited reactions. Mass transport properties of these conductive static mixers are evaluated in an additive manufactured electrochemical reactor under controlled conditions by applying the limiting‐current method.
High‐Stability Electrodes for High‐Temperature Proton Exchange Membrane Fuel Cells by Using Advanced Nanocarbonaceous Materials
Authors: Zamora Héctor , Plaza Jorge , Cañizares Pablo , Rodrigo Manuel A. , Lobato Justo
Published: September 2017

This work studies the stability and performance of a cathodic electrode for high‐temperature proton exchange membrane (HT‐PEMFC) systems prepared with a carbon nanosphere (CNS) based microporous layer and carbon nanofibers (CNFp) used as a catalyst support. The obtained results are compared with a standard Vulcan carbon XC72 based electrode. With this purpose, two membrane−electrode assemblies (MEAs) were prepared using the cathodic electrodes and tested in a 25 cm2 HT‐PEMFC system. Preliminary short‐life tests around 330 h were carried out with both MEAs. During the tests, different characterization procedures, consisting of polarization curves, spectroscopy impedance analysis, cyclic voltammetry and linear sweep voltammetry were performed in order to evaluate the evolution of the main stability and performance parameters of the MEAs. Results showed that the application of these new materials increases positively the stability of the MEA in comparison with the standard Vulcan carbon XC72 material, with a negligible decrease in the performance of the advanced MEA during all tests, making these results very promising to overcome the service lifetime limitations of these systems.
Intramolecular SEAr Reactions of Phosphorus Compounds: Computational Approach to the Synthesis of π‐Extended Heterocycles
Authors: Larrañaga Olatz , Romero‐Nieto Carlos , de Cózar Abel
Published: September 2017

The reaction mechanism associated with the synthesis of phosphorus‐based heteropolyaromatic architectures was investigated by DFT calculations at the B3LYP‐D3/6‐311+G(D) level of theory. The aim of this study is to provide essential information for the future development of improved polycyclic organophosphorus materials. To that end, the impact of the structure of the initial reactant and/or the intermediates structure on the mechanistic features and energetic profiles of the phosphorus cyclization process was studied. Moreover, the reactivity parameters were analyzed in detail in a conceptual DFT framework and the underlying reactivity trends were extracted. Thus, these findings provide important insights for a rational design of polycyclic phosphorus compounds.