bluuebunny/crossref_metadata_2025 huggingface dataset:
Inorganic Polymers (Geopolymers)
Authors: MacKenzie Kenneth J. D.
Published: November 2017

Conventional inorganic polymers, otherwise known as geopolymers, are aluminosilicates with the desirable properties of ceramics (durability, strength) but which harden at ambient temperatures without the need for processing at high temperatures. They are commonly formed by the action of alkalis or phosphoric acid on aluminosilicate minerals such as dehydroxylated clays and consist of randomly arranged three‐dimensional assemblages of silicate and aluminate units into an X‐ray amorphous structure. The presence of charge‐balancing ions such as Na+or K+within this structure gives them useful ion‐exchange properties similar to zeolites. Analogous inorganic polymers are known in which the silicate is partially replaced by germinate units, and the aluminate units are replaced by gallate, phosphate, or borate units, giving a range of materials with a variety of properties and potential applications. The physical properties of the inorganic polymers can be manipulated by the introduction of fibers, whereas their chemistry allows the introduction of bone‐forming elements, drugs and carbon nanotubes, providing them with porosity, bioactivity, or electronic functionality. Inorganic polymers with catalytic, photocatalytic, and fluorescent functionality can also be produced. This article covers the synthesis and structure of clay‐based inorganic polymers and discusses a number of their more specialized applications. Although inorganic polymers are a subclass of alkali‐activated materials that can also be formed by a range of materials other than dehydroxylated clays (fly ash, volcanic ash, blast furnace slag), geopolymers formed from these materials are outside the scope of this article, and are not discussed here.
Poly(vinylidene fluoride) Nanocomposites
Authors: Nandi Arun K. , Manna Swarup
Published: November 2017

This article overviews the current research trends in the field of electroactive polymer poly(vinylidene fluoride) (PVDF) composites with various nanofillers, such as clay, carbon nanotube, graphene, and inorganic nanoparticles. Here we give a concise account on the preparation and properties of different nanocomposites, highlighting some of their applications. Important aspects such as PVDF nanocomposite properties, morphology, structure, thermal stability, mechanical properties, phase transitions, crystallinity, conductivity, dielectric permittivity, piezoelectric polymorph formation, electromagnetic induction shielding etc. are discussed. Particular emphasis is given on the piezoelectric β‐phase formation and the subsequent improvement of mechanical properties, conductivity, dielectric permittivity, and electromagnetic shielding, which are of interest in the application of PVDF nanocomposites in both commodity and technological fields. Apart from the binary nanocomposites, ternary nanocomposites containing two nanofillers and their synergistic effect on PVDF properties are also discussed.
Helical Foldamers from Aromatic Polymers
Authors: Zhang Dan‐Wei , Wang Hui , Li Zhan‐Ting
Published: November 2017

Foldamers are synthetic linear molecules or macromolecules that adopt confined conformations induced by noncovalent forces. Conjugated polymers have relatively high rigidity. They can be induced by noncovalent interactions to fold into well‐predictable helical conformations. Backbones that have been developed for the formation of such polymeric helices include those composed of
m
‐arylene ethynylene, aromatic amide, hydrazide, urea, trizole, and axodiazole segments. Noncovalent interactions typically used as driving forces for the formation of such helical conformations include solvophobicity and intra‐ and/or intermolecular hydrogen bonding. In general, polymeric foldamers possess a tubular cavity with a well‐defined diameter. Their length or depth is defined by the degree of polymerization. Such polymeric foldamers are conformationally dynamic and can exhibit unique twist‐sense bias tuned by side‐chain chirality or by chiral guest induction. Moreover, such hollow unimacromolecular helices can function as efficient tubular receptors for discrete guests and as transmembrane channels for transporting different ions. This article summarizes the studies of helical foldamers formed by aromatic polymers and their properties and functions.
Polymer Synthesis: Copper‐Catalyzed Azide Alkyne Cycloaddition
Authors: Li Kewen , Oderinde Olayinka , Liu Shunli , Yao Fang , Fu Guodong
Published: November 2017

The Cu(I)‐catalyzed azide‐alkyne cycloaddition (CuAAC) reaction is one of the most widely employed “click” chemistry processes due to its ability to produce functional polymers and various architectures of polymers. Some unique properties of CuAAC include high selectivity, near‐perfect reliability, high yields, and exceptional tolerance toward a wide range of functional groups and reaction conditions. Furthermore, CuAAC is an extremely chemoselective reaction, which forms triazole; therefore, it can be used for functional polymer materials and also for modifying highly functional biomolecules such as polypeptides, nucleic acids, and polysaccharides. The application of CuAAC ‘‘clicking’’ in polymer chemistry is increasing exponentially, leading to fabrication of a growing family of well‐defined polymer materials with novel properties.
Injectable Hydrogels: Properties and Applications
Authors: Park Kyung Min , Park Ki Dong
Published: November 2017

In situ
forming hydrogels have been widely used as therapeutic implants and vehicles for a broad range of biomedical applications, including tissue regenerative medicine and drug delivery because of their biocompatibility and multitunable properties. These hydrogel materials have received considerable attention as injectable matrices because of easy encapsulation of the therapeutic agents during the hydrogel network formation as well as their minimally invasive injection into the target sites. In addition, the injectable hydrogel has also the advantage of an easy application to irregular defect sites. Furthermore, it is widely used as an artificial extracellular matrix because of its structural similarity with the native extracellular matrix of the human body and its multitunable properties. Various synthetic, natural, and bioinspired materials have been developed as injectable hydrogels by using different cross‐linking strategies. In this article, we discuss how the functional hydrogels are created with tunable physical, chemical, and biological properties. In particular, we focus on emerging techniques used to apply advanced hydrogel materials for tissue regenerative medicine.
The Importance of Splat Events to the Spatiotemporal Structure of Near‐Bed Fluid Velocity and Bed Load Motion Over Bed Forms: Laboratory Experiments Downstream of a Backward Facing Step
Authors: Leary K. C. P. , Schmeeckle M. W.
Published: November 2017

Flow separation/reattachment on the lee side of alluvial bed forms is known to produce a complex turbulence field, but the spatiotemporal details of the associated patterns of bed load sediment transported remain largely unknown. Here we report turbulence‐resolving, simultaneous measurements of bed load motion and near‐bed fluid velocity downstream of a backward facing step in a laboratory flume. Two synchronized high‐speed video cameras simultaneously observed bed load motion and the motion of neutrally buoyant particles in a laser light sheet 6 mm above the bed at 250 frames/s downstream of a 3.8 cm backward facing step. Particle Imaging Velocimetry (PIV) and Acoustic Doppler Velocimetry (ADV) were used to characterize fluid turbulent patterns, while manual particle tracking techniques were used to characterize bed load transport. Octant analysis, conducted using ADV data, coupled with Markovian sequence probability analysis highlights differences in the flow near reattachment versus farther downstream. Near reattachment, three distinct flow patterns are apparent. Farther downstream we see the development of a dominant flow sequence. Localized, intermittent, high‐magnitude transport events are more apparent near flow reattachment. These events are composed of streamwise and cross‐stream fluxes of comparable magnitudes. Transport pattern and fluid velocity data are consistent with the existence of permeable “splat events,” wherein a volume of fluid moves toward and impinges on the bed (sweep) causing a radial movement of fluid in all directions around the point of impingement (outward interaction). This is congruent with flow patterns, identified with octant analysis, proximal to flow reattachment.
Agreement of CMIP5 Simulated and Observed Ocean Anthropogenic CO2 Uptake
Authors: Bronselaer Benjamin , Winton Michael , Russell Joellen , Sabine Christopher L. , Khatiwala Samar
Published: November 2017

Previous studies found large biases between individual observational and model estimates of historical ocean anthropogenic carbon uptake. We show that the largest bias between the Coupled Model Intercomparison Project phase 5 (CMIP5) ensemble mean and between two observational estimates of ocean anthropogenic carbon is due to a difference in start date. After adjusting the CMIP5 and observational estimates to the 1791–1995 period, all three carbon uptake estimates agree to within 3 Pg of C, about 4% of the total. The CMIP5 ensemble mean spatial bias compared to the observations is generally smaller than the observational error, apart from a negative bias in the Southern Ocean and a positive bias in the Southern Indian and Pacific Oceans compensating each other in the global mean. This dipole pattern is likely due to an equatorward and weak bias in the position of Southern Hemisphere westerlies and lack of mode and intermediate water ventilation.
Flood Runoff in Relation to Water Vapor Transport by Atmospheric Rivers Over the Western United States, 1949–2015
Authors: Konrad Christopher P. , Dettinger Michael D.
Published: November 2017

Atmospheric rivers (ARs) have a significant role in generating floods across the western United States. We analyze daily streamflow for water years 1949 to 2015 from 5,477 gages in relation to water vapor transport by ARs using a 6 h chronology resolved to 2.5° latitude and longitude. The probability that an AR will generate 50 mm/d of runoff in a river on the Pacific Coast increases from 12% when daily mean water vapor transport, DVT, is greater than 300 kg m−1 s−1 to 54% when DVT > 600 kg m−1 s−1. Extreme runoff, represented by the 99th quantile of daily values, doubles from 80 mm/d at DVT = 300 kg m−1 s−1 to 160 mm/d at DVT = 500 kg m−1 s−1. Forecasts and predictions of water vapor transport by atmospheric rivers can support flood risk assessment and estimates of future flood frequencies and magnitude in the western United States.
Case Studies of Low‐Visibility Forecasting in Falling Snow With WRF Model
Authors: Huang Haibo , Zhang Guangxing
Published: November 2017

Accurate low‐visibility forecasts in falling snow are critical to the safety and efficiency of air traffic. The Weather and Research Forecast (WRF) model successfully captured two unusual snowstorms occurred in Urumqi. On this basis, the quality of 15 parameterizations for predicting visibility in snow is evaluated, using both observations and forecasts of the meteorological variables from WRF model. The parameterizations are mainly based on the relations between the extinction efficient (β) or visibility (Vis) and the snowfall rate (S). Comprehensive evaluations show that most of these parameterizations (13 of 15) are skillful as well as having the ability to predict low visibilities to some extent. Among them, the parameterization Vis = 0.62S−0.59 performs the best, followed by the approach of Stoelinga and Warner. It is also found that the visibility forecasts based on the observations always have considerably higher quality than the visibility forecasts from WRF model. The results suggest that more than one parameterization is promising if the WRF model is able to provide accurate predictions of the relevant meteorological variables. Furthermore, the forecast accuracy of low visibilities strongly depends on the accurate predictions of snowfall rate of greater than or equal to 1.0 mm h−1.
Diagnosing Cloud Biases in the GFDL AM3 Model With Atmospheric Classification
Authors: Evans Stuart , Marchand Roger , Ackerman Thomas , Donner Leo , Golaz Jean‐Christophe , Seman Charles
Published: November 2017

We define a set of 21 atmospheric states, or recurring weather patterns, for a region surrounding the Atmospheric Radiation Measurement Program's Southern Great Plains site using an iterative clustering technique. The states are defined using dynamic and thermodynamic variables from reanalysis, tested for statistical significance with cloud radar data from the Southern Great Plains site, and are determined every 6 h for 14 years, creating a time series of atmospheric state. The states represent the various stages of the progression of synoptic systems through the region (e.g., warm fronts, warm sectors, cold fronts, cold northerly advection, and high‐pressure anticyclones) with a subset of states representing summertime conditions with varying degrees of convective activity. We use the states to classify output from the NOAA/Geophysical Fluid Dynamics Laboratory AM3 model to test the model's simulation of the frequency of occurrence of the states and of the cloud occurrence during each state. The model roughly simulates the frequency of occurrence of the states but exhibits systematic cloud occurrence biases. Comparison of observed and model‐simulated International Satellite Cloud Climatology Project histograms of cloud top pressure and optical thickness shows that the model lacks high thin cloud under all conditions, but biases in thick cloud are state‐dependent. Frontal conditions in the model do not produce enough thick cloud, while fair‐weather conditions produce too much. We find that increasing the horizontal resolution of the model improves the representation of thick clouds under all conditions but has little effect on high thin clouds. However, increasing resolution also changes the distribution of states, causing an increase in total cloud occurrence bias.
Enhanced Recent Local Moisture Recycling on the Northwestern Tibetan Plateau Deduced From Ice Core Deuterium Excess Records
Authors: An Wenling , Hou Shugui , Zhang Qiong , Zhang Wangbin , Wu Shuangye , Xu Hao , Pang Hongxi , Wang Yetang , Liu Yaping
Published: November 2017

Local moisture recycling plays an essential role in maintaining an active hydrological cycle of the Tibetan Plateau (TP). Previous studies were largely limited to the seasonal time scale due to short and sparse observations, especially for the northwestern TP. In this study, we used a two‐component mixing model to estimate local moisture recycling over the past decades from the deuterium excess records of two ice cores (i.e., Chongce and Zangser Kangri) from the northwestern TP. The results show that on average almost half of the precipitation on the northwestern TP is provided by local moisture recycling. In addition, the local moisture recycling ratio has increased evidently on the northwestern TP, suggesting an enhanced hydrological cycle. This recent increase could be due to the climatic and environmental changes on the TP in the past decades. Rapid increases in temperature and precipitation have enhanced evaporation. Changes of land surface of plateau have significantly increased evapotranspiration. All of these have intensified local moisture recycling. However, the mixing model used in this study only includes a limited number of climate factors. Some of the extreme values of moisture recycling ratio could be caused by large‐scale atmospheric circulation and other climatic and weather events. Moreover, the potential mechanisms for the increase in local recycling need to be further examined, since the numeric simulations from climate models did not reproduce the increased contribution of local moisture recycling in precipitation.
Use of Tethered Hydrogel Microcoatings for Mesenchymal Stem Cell Equilibrium, Differentiation, and Self‐Organization into Microtissues
Authors: Green David W. , Watson Gregory S. , Watson Jolanta A. , Lee Jong‐Min , Jung Han‐Sung
Published: November 2017

Therapeutic adult mesenchymal stem cells (MSCs) lose multipotency and multilineage specialization in culture and after transplantation due to the absence of complex biological architecture. Here, it is shown that a transient ultrathin covering of permeable biomaterial can be differentially formulated to either preserve multipotency or induce multidifferentiation. Accordingly, populations of single, spherical MSCs in suspended media with high selectivity and specificity can be coated. Assembly of single, double, and triple hydrogel layers at MSC membranes is initiated by first attaching MSC‐specific immunoglobulins onto CD90 or Stro‐1 receptors and UEA‐1 and soybean lectins. A secondary biotinylated immunoglobulin is targeted for avidin binding, which becomes an attractor for biotinylated alginate or hyaluronate, which are subsequently stiffened and gelled, in situ around the entire cell surface. Alginate microcoatings permeated with mobile BMP‐2‐induced osteospecialized tissue, vascular endothelial growth factor (VEGF) induced microcapillary formation, while microcoatings, with selected basement membrane proteins, preserve the multipotent phenotype of MSCs, for continuing rounds of culture and directed specialization. Furthermore, forced packing of microcoated MSC populations creates prototypical tissue compartments: the coating partially simulating the extracellular matrix structures. Remarkably, microcoated MSC clusters show a tremendous simulation of a common embryological tissue transformation into the epithelium. Thus, confinement of free morphology exerts another control on tissue specialization and formation.
An Evaporative Initiated Chemical Vapor Deposition Coater for Nanoglue Bonding
Authors: Randall Greg C. , Gonzalez Luis , Petzoldt Ron , Elsner Fred
Published: November 2017

The authors present an evaporative initiated chemical vapor deposition (iCVD) coater and use it to establish a submicron bonding process for millimeter‐scale foils with potentially rough surface features. The coater uses a simple benchtop design suited to research labs, with pre‐heated metal pins instead of hot filaments, and direct evaporation of reactants within the chamber. Coatings of poly(glycidyl methacrylate) (pGMA) with thickness 100–800 nm are achieved at rates of 10–40 nm min−1 on substrates common in high energy laser compression experiments. Coating uniformities of 10–30 nm mm−1 are demonstrated in a ≈60 × 10 mm zone under the heated pins. As an aside, the authors further show the ability to coat intentionally non‐uniform layers in a monomer vapor diffusion gradient. Coatings are formed on both plastics and solids ranging from smooth, non‐burred silicon or lithium fluoride to rough and burred metals (aluminum and copper). These coated substrates are then chemically bonded under mild heat and pressure. Detailed surface, thickness, and cross‐sectional characterization is performed to confirm a submicron bond gap and to troubleshoot the common clearance issues from burrs, roughness, and surface curvature. Peeling and dropping bond strength tests confirm the bonds are robust, when coated and assembled under conditions to mitigate clearance issues.
Conductive Nanocrystalline Niobium Carbide as High‐Efficiency Polysulfides Tamer for Lithium‐Sulfur Batteries
Authors: Cai Wenlong , Li Gaoran , Zhang Kailong , Xiao Guannan , Wang Can , Ye Kefen , Chen Zhongwei , Zhu Yongchun , Qian Yitai
Published: November 2017

Rational design of functional interlayer is highly significant in pursuit of high‐performance Li‐S batteries. Herein, a nanocrystalline niobium carbide (NbC) is developed via a facile and scalable autoclave technology, which is, for the first time, employed as the advanced interlayer material for Li‐S batteries. Combining the merits of strong polysulfides (PS) anchoring with high electric conductivity, the NbC‐coated membrane enables efficiently tamed PS shuttling and fast sulfur electrochemistry, achieving outstanding cyclability with negligible capacity fading rate of 0.037% cycle−1 over 1500 cycles, superb rate capability up to 5 C, high areal capacity of 3.6 mA h cm−2 under raised sulfur loading, and reliable operation even in soft‐package cells. This work offers a facile and effective method of promoting Li‐S batteries for practical application.
Directional Scattering in a Germanium Nanosphere in the Visible Light Region
Authors: Ma Churong , Yan Jiahao , Huang Yingcong , Yang Guowei
Published: November 2017

Previous designs of photonic nanoantennas are based on noble metal plasmonic structures, suffering from large ohmic loss and only possessing dipolar plasmon modes. This has driven the intense search for all‐dielectric materials (ADMs) beyond noble metals. Here, for the first time, a strong scattering anisotropy in a Ge nanosphere is demonstrated in the visible and near‐infrared regions. The forward‐to‐backward scattering ratio for an individual Ge nanosphere (150 nm) can reach a maximum value of ≈20 theoretically and ≈8 experimentally. This scattering behavior derives from the special real part and imaginary part of refractive index of Ge. Differing form other high‐index ADMs such as Si and GaAs, the electric dipole and magnetic dipole resonances of Ge nanospheres are closer to each other in the spectrum due to the non‐negligible imaginary part of refractive index. The spectral overlap between electric dipole and magnetic dipole resonances endows Ge nanospheres with efficient directional scattering near the scattering peak. Fano resonances with strong directivity are observed in Ge nanosphere dimers, which is the result of a broad electric gap mode coupled with a hybrid magnetic mode. These findings make Ge nanospheres a promising candidate for nanoantennas, directional sources, and optical switches.
Feasible D1–A–D2–A Random Copolymers for Simultaneous High‐Performance Fullerene and Nonfullerene Solar Cells
Authors: Jeong Mingyu , Chen Shanshan , Lee Sang Myeon , Wang Zhiwei , Yang Yankang , Zhang Zhi‐Guo , Zhang Chunfeng , Xiao Min , Li Yongfang , Yang Changduk
Published: November 2017

A series of PBDB‐TTn random donor copolymers is synthesized, consisting of an electron‐deficient benzo[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione (BDD) unit and different ratios of two electron‐rich benzo[1,2‐b:4,5‐b′]dithiophene (BDT) and thieno[3,2‐b]thiophene (TT) units, with intention to modulate the intrachain and/or interchain interactions and ultimately bulk‐heterojunction morphology evolution. A comparative study using 4 × 2 polymer solar cell (PSC) performance maps and each of the [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM) and the fused‐aromatic‐ring‐based molecule (m‐ITIC) acceptors are carried out. Given the similarities in their absorption ranges and energy levels, the PBDB‐TTn copolymers clearly reveal a change in the absorption coefficients upon optimization of the BDT to TT ratio in the backbone. Among the given acceptor combination sets, superior performances are observed in the case of PBDB‐TT5 blended with PC71BM (8.34 ± 0.10%) or m‐ITIC (11.10 ± 0.08%), and the dominant factors causing power conversion efficiency differences in them are found to be distinctly different. For example, the performances of PC71BM‐based PSCs are governed by size and population of face‐on crystallites, while intermixed morphology without the formation of large phase‐separated aggregates is the key factor for achieving high‐performance m‐ITIC‐based PSCs. This study presents a new sketch of structure–morphology–performance relationships for fullerene‐ versus nonfullerene‐based PSCs.
Gel Polymer Electrolytes for Electrochemical Energy Storage
Authors: Cheng Xunliang , Pan Jian , Zhao Yang , Liao Meng , Peng Huisheng
Published: November 2017

With the booming development of flexible and wearable electronics, their safety issues and operation stabilities have attracted worldwide attentions. Compared with traditional liquid electrolytes, gel polymer electrolytes (GPEs) are preferred due to their higher safety and adaptability to the design of flexible energy storage devices. This review summarizes the recent progress of GPEs with enhanced physicochemical properties and specified functionalities for the application in electrochemical energy storage. Functional GPEs that are capable to achieve unity lithium‐ion transference number and offer additional pseudocapacitance to the overall capacitance are carefully discussed. The smart GPEs with self‐protection, thermotolerant, and self‐healing abilities are particularly highlighted. To close, the future directions and remaining challenges of the GPEs for application in electrochemical energy storages are summarized to provide clues for the following development.
Uncertainty of food contamination origin and liability rules: Implications for bargaining power
Authors: Boutouis M.Z. , Hammoudi A. , Benhassine W. , Perito M.A.
Published: November 2017

We propose an industrial organization model to analyze the role of bargaining power and liability rules in creating incentives for downstream and upstream supply chain operators to invest in good practices. We investigate the case in which either upstream production practices or downstream distribution may cause product contamination resulting in noncompliance with the authorized thresholds of residues (maximum residue limit [MRL]). We provide a comparative analysis of the retailers’ liability rule‐based accountability and the liability rule “polluter pays,” which penalizes an operator who is directly responsible for a noncompliant product. We show that choosing the optimal liability rule is a complex problem, as the choice depends on the effectiveness of food safety controls and on the magnitude of the fine associated with rejecting noncompliant products. Moreover, the choice of the liability rule can change the negotiating power of both operators and, according to the rule chosen, the retailer will have to pay a higher or lower input price. [EconLit citations: L15, L22, Q18].
Association between objectively measured sedentary behavior and a criterion measure of obesity among adults
Authors: Mun Junbae , Kim Youngdeok , Farnsworth James L. , Suh Sunghyeok , Kang Minsoo
Published: November 2017

Objective

Results of published studies on the association between sedentary behavior (SB) and obesity are inconsistent, possibly due to reliance on subjective measures of SB and inappropriate measures of obesity. The aim of this study was to examine the relationship between objectively measured SB and criterion‐measured obesity among adults.

Methods

A total of 2284 adults (≥18 years) from the 2003 to 2004 National Health and Nutrition Examination Survey were included in the analysis. The participants were categorized into tertiles of SB time measured by accelerometry. Obesity was determined using body fat percentage measured by dual‐energy X‐ray absorptiometry.

Results

Increased SB was significantly associated with obesity when controlling for covariates related to demographics, health behaviors, energy intake, and physical activity (P for trends = .025).

Conclusions

This finding suggests that avoiding SB may be beneficial for lowering the risk of obesity in adults.
Echogenic bowel in the second trimester – Where to from here?
Authors: Chung Kimberly , Thayalan Krishanthy , Kothari Alka
Published: November 2017

Echogenic bowel is a ‘soft marker’ on prenatal ultrasound, which can be associated with a variety of conditions including chromosomal disorders, intrapartum infections, antepartum events and cystic fibrosis. Identification of this marker should prompt a further search for other soft markers, structural defects and placental abnormalities. We explore three cases of echogenic bowel identified on routine ultrasound scan. The first case highlights the potential for echogenic bowel to be a benign feature. Echogenic bowel was identified at eighteen weeks, which was attributed to intra‐amniotic haemorrhage and consequent fetal ingestion of blood products. In contrast, the next two cases highlight the pathological causes of echogenic bowel. In case 2, echogenic bowel was identified at seventeen weeks with associated cystic hygromas. The fetus had positive testing for Turner syndrome, and notably, there was a family history of cystic fibrosis. The third case discusses a case of congenital cytomegalovirus infection, which was diagnosed with amniocentesis and maternal serology testing when echogenic bowel was identified. A review of the literature suggests that the risk of adverse outcomes is increased with the presence of multiple soft markers, associated deformities, poor growth, persistent echogenic bowel in the third trimester and increased echogenic resolution. Despite these factors, it is important to note the poor ultrasonographic sensitivity of less than 50% in neonates with congenital cytomegalovirus infection and the consequent importance of invasive testing. Therefore, we aim to propose an action plan for clinicians who identify echogenic bowel on prenatal scans in order to critically exclude detrimental pathology.
Atropoenantioselective Redox‐Neutral Amination of Biaryl Compounds through Borrowing Hydrogen and Dynamic Kinetic Resolution
Authors: Zhang Jianwei , Wang Jian
Published: November 2017

We report herein a novel atropoenantioselective redox‐neutral amination of biaryl compounds triggered by a cascade of borrowing hydrogen and dynamic kinetic resolution under the cooperative catalysis of a chiral iridium complex and an achiral Brønsted acid. This protocol features broad substrate scope and good functional‐group tolerance, and allows the rapid assembly of axially chiral biaryl compounds in good to high yields and with high to excellent enantioselectivity.
Impact of lignin extraction methods on microstructure and mechanical properties of lignin‐based carbon fibers
Authors: Shi Xiaojuan , Wang Xing , Tang Biao , Dai Zhong , Chen Kefu , Zhou Jinghui
Published: November 2017

In order to optimize the use of residues of enzymatic hydrolysis of corn stalk (REHCS) and explore the low‐cost and sustainable raw material substitute for carbon fibers, three types of lignin samples were extracted from REHCS by various extraction methods, and then they were converted into carbon fibers (CFs) by electrospinning, thermostabilization, and carbonization under the same process conditions. The microstructure and mechanical properties of the three types of carbonized fibers were different. The CFs from the ethanol organosolv lignin were actually smooth and brittle carbon films. The CFs from the formic acid/acetic acid organosolv lignin had microscopic pores, causing poor mechanical properties. Comparatively, the CFs from the alkaline lignin demonstrated preferable microstructure and mechanical properties. The reasons for the differences were analyzed by characterizing the lignin samples, precursor fibers, and resultant CFs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45580.
Infrared laser‐ignited horizontal frontal polymerization of versatile unsaturated polyester resins
Authors: Tsegay Nigus Mesele , Du Xiang‐Yun , Ma Kangzhe , Li Qing , Wang Cai‐Feng , Chen Su
Published: November 2017

Infrared laser‐ignited horizontal frontal polymerization is applied for the synthesis of unsaturated polyester resin (UPER) by copolymerizing unsaturated polyester with styrene (St), methyl methacrylate (MMA), and 2‐dimethylamino ethyl methacrylate (DMAEMA) monomers. Dependence of frontal velocity and temperature on the initiator and monomer concentration is discussed for St‐based UPER. These resins have also been characterized by Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy. The results reveal St‐based resins have superior crosslinked networks. Besides, the thermo‐pH responsiveness behaviors of DMAEMA‐based resins are demonstrated by swelling measurements under the conditions of different temperatures and pH values. Moreover, by introducing CdSe@ZnS quantum dots and CsPbBr3 perovskites into St‐ and MMA‐based resins, respectively, we realize the in situ generation of CdSe@ZnS‐UPER and CsPbBr3‐UPER composites with good fluorescence properties and fluorescent stability, which have potential application in optoelectronic devices such as light‐emitting diode and perovskite solar cells. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45935.
Quaternized poly(2.6 dimethyl‐1.4 phenylene oxide)/polysulfone blend composite membrane doped with ZnO‐nanoparticles for alkaline fuel cells
Authors: Msomi Phumlani Fortune , Nonjola Patrick , Ndungu Patrick Gathura , Ramonjta James
Published: November 2017

A series of quaternized poly(2.6 dimethyl‐1.4 phenylene oxide)/polysulfone (QPPO/PSF) blend anion exchange membrane (AEM) were successfully fabricated and characterized for alkaline fuel cell application. Zinc oxide (ZnO) nanoparticles were introduced in the polymer matrix to enhance the intrinsic properties of the AEM. To confirm successful fabrication, Fourier‐transform infrared spectroscopy and nuclear magnetic resonance (1H‐NMR) were used. The membrane properties were enhanced by the addition of ZnO nanoparticles. The addition of ZnO nanoparticles resulted to a higher ion exchange capacity (IEC) of 3.72 mmol g−1, increase of ion conductivity (IC) up to 52.34 mS cm−1 at 80 °C, enhancement of water uptake, and reduced methanol permeability. The QPPO/PSF/2% ZnO composite retained over 80% of its initial IC at room temperature and also retained over 50% of its initial IC at 80 °C when evaluated for alkaline stability. The maximum power output reached for the membrane electrode assembly constructed with QPPO/PSF/2%ZnO was 69 mW cm−2 at room temperature, which is about three times more than the parent QPPO membrane. The above results indicate that QPPO/PSF/ZnO is a good candidate as an AEM for fuel cell application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45959.
Fabrication of a functionally graded and magnetically responsive shape memory polymer using a 3D printing technique and its characterization
Authors: Hassan Rizwan Ul , Jo Soohwan , Seok Jongwon
Published: November 2017

In this study, a three‐dimensional printing technique is applied for the fabrication of novel functionally graded magnetic shape memory polymers (SMPs) to create high‐resolution multimaterial shape memory architectures. This approach is applied to a copolymer network of photocurable methacrylate using high projection stereolithography. Carbonyl iron particles (CIPs) were physically embedded in a polymer matrix to add magnetic functions to the SMPs. The glass transition characteristics and shape memory effect were also investigated by varying the composition of the SMP. The microstructured, lightweight SMPs showed interesting shape memory behaviors, as observed in hot environment. The almost perfect strain recovery rate of poly(ethylene glycol) dimethacrylate was measured (99.95% using a tension set bar). The results of dynamic mechanical analysis and thermogravimetric analysis reveal an increment in the thermal conductivity after embedding the CIPs. Further, the results of dynamic mechanical analysis, differential scanning calorimetry, and scanning electron microscopy reveal close interaction between the particles and matrix. X‐ray diffraction was used to characterize the iron particles and polymer structure. These results, along with the electrical and magnetic tests, strongly support the remote controllability of the material properties of the present functionally graded magnetic SMPs for a broad range of temperature and/or magnetically responsive material applications by using eddy current heating and/or magnetorheological polymeric effects. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45997.
Synthesis of phosphorus‐ and phenyl‐based ROMP polymers and investigation of their effects on the thermomechanical and flammability properties of a polypropylene–IFR system
Authors: Turgut Gizem , Işıksel Ecem , Kahraman Gizem , Eren Tarik , Özkoç Güralp
Published: November 2017

In this study, we present an approach for the synthesis of novel phosphorous‐ or phenyl‐ containing polymers, 2phenyl, 3phospho, and 2phenyl‐co‐3phospho, derived from ring‐opening metathesis polymerization (ROMP), to reduce the flammability of polypropylene (PP). The composites were processed by melt‐blending ROMP polymers and octaphenyl–polyhedral oligomeric silsesquioxane with PP/intumescent flame retardant (IFR) compounds at different compositions. The composites were characterized by limiting oxygen index (LOI), UL‐94, and mechanical tests as well as thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The molecular structures of phosphorous‐ and phenyl‐containing polymers were proved by 1H‐NMR, 13C‐NMR, and Fourier transform infrared spectroscopy. The online rheological measurements indicated that the addition of additives to the PP/IFR system increased the melt viscosity of the compounds regardless of the type. The DSC analysis showed that the addition of ROMP polymers to the PP/IFR system influenced the crystal perfection and degree of crystallization. TGA analysis of the composites revealed that the addition of ROMP polymers to PP/IFR compounds deteriorated the thermal stability as the amount of phosphorus increased in the matrix. Dynamic mechanical properties such as storage modulus (E′) and loss modulus (E″) of the composites were lowered by the addition of ROMP polymers. The LOI and UL‐94 rating of PP/IFR were enhanced by the addition of ROMP polymers. It was successfully demonstrated that the novel phosphorous‐ or phenyl‐containing polymers were highly potent additives in optimizing the flammability of PP composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45998.
18F‐Fluorodeoxyglucose–Positron Emission Tomography As an Imaging Biomarker in a Prospective, Longitudinal Cohort of Patients With Large Vessel Vasculitis
Authors: Grayson Peter C. , Alehashemi Sara , Bagheri Armin A. , Civelek Ali Cahid , Cupps Thomas R. , Kaplan Mariana J. , Malayeri Ashkan A. , Merkel Peter A. , Novakovich Elaine , Bluemke David A. , Ahlman Mark A.
Published: November 2017

Objective

To assess the clinical value of18F‐fluorodeoxyglucose (FDG) positron emission tomography (PET) in a prospective cohort of patients with large vessel vasculitis (LVV) and comparator subjects.

Methods

Patients with Takayasu arteritis and giant cell arteritis were studied, along with a comparator group consisting of patients with hyperlipidemia, patients with diseases that mimicLVV, and healthy controls. Participants underwent clinical evaluation andFDG‐PETimaging, and patients withLVVunderwent serial imaging at 6‐month intervals. We calculated sensitivity and specificity ofFDG‐PETinterpretation for distinguishing patients with clinically activeLVVfrom comparator subjects and from patients with disease in clinical remission. A qualitative summary score based on global arterialFDGuptake, thePETVascular Activity Score (PETVAS), was used to study associations between activity onPETscan and clinical characteristics and to predict relapse.

Results

A total of 170FDG‐PETscans were performed in 115 participants (56 patients withLVVand 59 comparator subjects).FDG‐PETdistinguished patients with clinically activeLVVfrom comparator subjects with a sensitivity of 85% (95% confidence interval [95%CI] 69, 94) and a specificity of 83% (95%CI71, 91).FDG‐PETscans were interpreted as active vasculitis in most patients withLVVin clinical remission (41 of 71 [58%]). Clinical disease activity status, disease duration, body mass index, and glucocorticoid use were independently associated with activity onPETscan. Among patients who underwentPETduring clinical remission, future clinical relapse was more common in patients with a highPETVASthan in those with a lowPETVAS(55% versus 11%;P = 0.03) over a median follow‐up period of 15 months.

Conclusion

FDG‐PETprovides information about vascular inflammation that is complementary to, and distinct from, clinical assessment inLVV.FDG‐PETscan activity during clinical remission was associated with future clinical relapse.
Improved Dehydrogenation Properties of LiBH4 Using Catalytic Nickel‐ and Cobalt‐based Mesoporous Oxide Nanorods
Authors: Zang Lei , Zhang Qiuyu , Li Li , Huang Yike , Chang Xiaoya , Jiao Lifang , Yuan Huatang , Wang Yijing
Published: November 2017

Lithium borohydride (LiBH4) with a theoretical hydrogen storage capacity of 18.5 wt % has attracted intense interest as a high‐density hydrogen storage material. However, high dehydrogenation temperatures and limited kinetics restrict its practical applications. In this study, mesoporous nickel‐ and cobalt‐based oxide nanorods (NiCo2O4, Co3O4 and NiO) were synthesized in a controlled manner by using a hydrothermal method and then mixed with LiBH4 by ball milling. It is found that the dehydrogenation properties of LiBH4 are remarkably enhanced by doping the as‐synthesized metal oxide nanorods. When the mass ratio of LiBH4 and oxides is 1:1, the NiCo2O4 nanorods display the best catalytic performance owing to the mesoporous rod‐like structure and synergistic effect of nickel and cobalt active species. The initial hydrogen desorption temperature of the LiBH4‐NiCo2O4 composite decreases to 80 °C, which is 220 °C lower than that of pure LiBH4, and 16.1 wt % H2 is released at 500 °C for the LiBH4‐NiCo2O4 composite. Meanwhile, the composite also exhibits superior dehydrogenation kinetics, which liberates 5.7 wt % H2 within 60 s and a total of 12 wt % H2 after 5 h at 400 °C. In comparison, pure LiBH4 releases only 5.3 wt % H2 under the same conditions.
Engineering Mammalian Designer Cells for the Treatment of Metabolic Diseases
Authors: Wang Yidan , Wang Meiyan , Dong Kaili , Ye Haifeng
Published: November 2017

Synthetic biology applies engineering principles to biological systems and has significantly advanced the design of synthetic gene circuits that can reprogram cell activities to perform new functions. The ability to engineer mammalian designer cells with robust therapeutic behaviors has brought new opportunities for treating metabolic diseases. In this review, the authors highlight the most recent advances in the development of synthetic designer cells uploaded with open‐ or closed‐loop gene circuits for the treatment of metabolic disorders including diabetes, hypertension, hyperuricemia, and obesity, and discuss the current technologies and future perspectives in applying these designer cells for clinical applications. In the future, more and more rationally designed cells will be constructed and revolutionized to treat a number of metabolic disorders in an intelligent manner.
Value of social media in advancing surgical research
Authors: Mayol J , Dziakova J
Published: November 2017

Spreading the word
Metabolic profiling of normal hepatocyte and hepatocellular carcinoma cells via 1H nuclear magnetic resonance spectroscopy
Authors: Chen Yang , Chen Zhong , Feng Jiang‐Hua , Chen Yun‐Bin , Liao Nai‐Shun , Su Ying , Zou Chang‐Yan
Published: November 2017

Hepatocellular carcinoma (HCC) causes death mainly by disseminated metastasis progression from the organ being confined. Different metastatic stages are closely related to cellular metabolic profiles. Normal hepatocyte and HepG2 cell line from low metastatic HCC were studied by NMR‐based metabolomic techniques. Multivariate and univariate statistical analyses were utilized to identify characteristic metabolites from cells and cultured media. Elevated levels of acetate, creatine, isoleucine, leucine, and phenylalanine were observed in HepG2 cells, suggesting more active in gathering nutrient components along with altered amino acid metabolisms and enhanced lipid metabolism. High glucose consumption was significantly different in low metastatic cells. A series of characteristic metabolites were identified and served as biomarkers. Relative metabolic pathway analysis shows that low metastatic HepG2 cell line exhibits active behaviors in metabolisms and biosynthesis of specific amino acids and energy metabolism. Moreover, characteristic metabolites‐based classification models executed by support vector machines algorithm perform robustly to classify normal hepatocyte and HepG2 cell line. It is concluded that NMR‐based metabolomic analyses of cell lines can provide a powerful approach to understand metastasis‐related biological alterations. The present study also provides a basis for metabolic markers determination of hepatic carcinoma in the future clinical study.
Emulsion Prevention with Supported Liquid Membrane Permeation
Authors: Kienberger Marlene , Hackl Markus , Siebenhofer Matthäus
Published: November 2017

The urge to achieve climate protection goals and a more prevalent interest in finding alternatives to fossil fuel‐based products focus attention increasingly on cascade raw material utilization, respectively, to intensify commercial production processes. The present project provides a study on the combination of liquid‐liquid extraction and esterification using the system acetic acid/octanol and 4‐dodecylbenzenesulfonic acid as catalyst. The surfactant 4‐dodecylbenzenesulfonic acid causes emulsification during extraction, but emulsification was successfully avoided by using supported liquid membrane permeation equipment.
Catalytic Synthesis of Indolines by Hydrogen Atom Transfer to Cobalt(III)–Carbene Radicals
Authors: Karns Alexander S. , Goswami Monalisa , de Bruin Bas
Published: November 2017

We report a new method for the synthesis of indolines from o‐aminobenzylidine N‐tosylhydrazones proceeding through a cobalt(III)–carbene radical intermediate. This methodology employs the use of inexpensive commercially available reagents and allows for the transformation of easily derivatized benzaldehyde‐derived precursors to functionalized indoline products. This transformation takes advantage of the known propensity of radicals to undergo rapid intramolecular 1,5‐hydrogen atom transfer (1,5‐HAT) to form more stabilized radical intermediates. Computational investigations using density functional theory identify remarkably low barriers for 1,5‐HAT and subsequent radical rebound displacement, providing support for the proposed mechanism. We explore the effect of a variety of nitrogen substituents, and highlight the importance of adequate resonance stabilization of radical intermediates to the success of the transformation. Furthermore, we evaluate the steric and electronic effects of substituents on the aniline ring. This transformation is the first reported example of the synthesis of nitrogen‐containing heterocycles from cobalt(III)–carbene radical precursors.
Effect of Second‐Order Spin–Orbit Coupling on the Interaction between Spin States in Spin‐Crossover Systems
Authors: Sousa Carmen , Domingo Alex , de Graaf Coen
Published: November 2017

The second‐order spin–orbit coupling is evaluated in two transition‐metal complexes to establish the effect on the deactivation mechanism of the excited low‐spin state in systems that undergo spin transitions under the influence of light. We compare the standard perturbational approach to calculate the second‐order interaction with a variational strategy based on the effective Hamiltonian theory and show that the former one can only be applied in some special cases and even then gives results that largely overestimate the interaction. The combined effect of geometry distortions and second‐order spin–orbit coupling leads to sizeable interactions for states that are nearly uncoupled in the symmetric (average) structure of the complex. This opens the possibility of a direct deactivation from the singlet and triplet states of the metal‐to‐ligand charge‐transfer manifold to the final high‐spin state as suggested from the interpretation of experimental data but so far not supported by theoretical descriptions of the light‐induced spin crossover.