bluuebunny/crossref_metadata_2025 huggingface dataset:
Organic Light‐Emitting Transistors: Advances and Perspectives
Authors: Chaudhry Mujeeb Ullah , Muhieddine Khalid , Wawrzinek Robert , Sobus Jan , Tandy Kristen , Lo Shih‐Chun , Namdas Ebinazar B.
Published: November 2019

The rapid development of charge transporting and light‐emitting organic materials in the last decades has advanced device performance, highlighting the high potential of light‐emitting transistors (LETs). Demonstrated for the first time over 15 years ago, LETs have transformed from an optoelectronic curiosity to a serious competitor in the race for cheaper and more efficient displays, also showing promise for injection lasers. Thus, what is an LET, how does it work, and what are the current challenges for its integration into mainstream technologies? Herein, some light is shed on these questions. This work also provides the fundamental working principle of LETs, materials that have been used, and device physics and architectures involved in the progression of LET technology. The state‐of‐the‐art development of LETs is also explored as prospect avenues for the future of research and applications in this area.
A Visible‐ and NIR‐Light Responsive Photothermal Therapy Agent by Chirality‐Dependent MoO3−x Nanoparticles
Authors: Li Yiwen , Miao Ziwei , Shang Zhengwen , Cai Ying , Cheng Jiaji , Xu Xiaoqian
Published: November 2019

Chirality‐based semiconducting nanocrystals, as an emerging area, are envisioned to have great potential in chiral sensing, biomedicine, and chiroptical devices. Herein, chiral substoichiometric molybdenum oxide (l/d‐Cys‐MoO3−x) nanoparticles are synthesized via step‐by‐step reduction treatment with chiral cysteine molecules. The obtained nanoparticles are used as visible‐ and near‐infrared‐light dual responsive photothermal therapy agent for tumor cell ablation. Notably, the chiral nanoparticles show chiral selectivity for incident light, i.e., when irradiated by left‐circularly polarized light, l‐Cys‐MoO3−x is the most sensitive agent giving the highest mortality for HeLa cell ablation in vitro, and vice versa for right‐circularly polarized light with d‐Cys‐MoO3−x. In comparison to traditional photothermal therapy with near‐field light source, the investigations with chiral visible light at 532 nm indicate the possibility of chiral Cys‐MoO3−x nanoparticles for visible light‐based phototherapy via metal–ligand charge transfer chirality, which provides insights for new methods in nanotechnology supported photothermal treatments.
Layered‐Herringbone Polymorphs and Alkyl‐Chain Ordering in Molecular Bilayer Organic Semiconductors
Authors: Arai Shunto , Morita Kaede , Tsutsumi Jun'ya , Inoue Satoru , Tanaka Mutsuo , Hasegawa Tatsuo
Published: November 2019

Production and control of 2D self‐organized layers of π‐conjugated molecules is a fundamental issue in organic electronics devices. This study reports that an intralayer polymorphic transformation is apparently observed in abilayer‐type layered‐herringbonepacking of a series of 2‐mono‐alkylated‐benzothieno[3,2‐b][1]benzothiophenes (mono‐Cn‐BTBTs) with the change in the substituted alkyl‐chain length,n. Slight variation in the intermolecular arrangement in the single‐crystal films is investigated with reasonable sensitivity via polarized optical absorption spectroscopy through the excitonic interactions between neighboring π‐electron cores. A clear polymorphic transition is observed based on the features of the in‐plane optical anisotropy with the change in the chain length betweenn= 7 (or less) and 8 (or more). A unique phase separation of the polymorphs is also observed in the films produced using a mixed solution with molecules having differentn: the respective polymorphic phases appear separately, either as single molecular bilayers or multibilayer‐stacked films owing to geometrical frustration. The results indicate that the intralayer packing motif is predetermined by the competition and balance between the intermolecular core–core and chain–chain interactions. These findings pave the way for rational designing of organic molecules with considerably high layered crystallinity, and thus, of efficient carrier transport in organic thin‐film transistors.
Coreless Fiber‐Based Whispering‐Gallery‐Mode Assisted Lasing from Colloidal Quantum Well Solids
Authors: Sak Mustafa , Taghipour Nima , Delikanli Savas , Shendre Sushant , Tanriover Ibrahim , Foroutan Sina , Gao Yuan , Yu Junhong , Yanyan Zhou , Yoo Seongwoo , Dang Cuong , Demir Hilmi Volkan
Published: November 2019

Whispering gallery mode (WGM) resonators are shown to hold great promise to achieve high‐performance lasing using colloidal semiconductor nanocrystals (NCs) in solution phase. However, the low packing density of such colloidal gain media in the solution phase results in increased lasing thresholds and poor lasing stability in these WGM lasers. To address these issues, here optical gain in colloidal quantum wells (CQWs) is proposed and shown in the form of high‐density close‐packed solid films constructed around a coreless fiber incorporating the resulting whispering gallery modes to induce gain and waveguiding modes of the fiber to funnel and collect light. In this work, a practical method is presented to produce the first CQW‐WGM laser using an optical fiber as the WGM cavity platform operating at low thresholds of ≈188 µJ cm−2 and ≈1.39 mJ cm−2 under one‐ and two‐photon absorption pumped, respectively, accompanied with a record low waveguide loss coefficient of ≈7 cm−1 and a high net modal gain coefficient of ≈485 cm−1. The spectral characteristics of the proposed CQW‐WGM resonator are supported with a numerical model of full electromagnetic solution. This unique CQW‐WGM cavity architecture offers new opportunities to achieve simple high‐performance optical resonators for colloidal lasers.
Photoinduced Directional Proton Transport through Printed Asymmetric Graphene Oxide Superstructures: A New Driving Mechanism under Full‐Area Light Illumination
Authors: Zhang Yanbing , Li Fengyu , Kong Xian , Xue Tangyue , Liu Dan , Jia Pan , Wang Lili , Ding Liping , Dong Huanli , Lu Diannan , Jiang Lei , Guo Wei
Published: November 2019

2D‐material‐based membranes with densely packed sub‐nanometer‐height fluidic channels show exceptional transport properties, and have attracted broad research interest for energy‐, environment‐, and healthcare‐related applications. Recently, light‐controlled active transport of ionic species in abiotic materials have received renewed attention. However, its dependence on inhomogeneous or site‐specific illumination is a challenge for scalable application. Here, directional proton transport through printed asymmetric graphene oxide superstructures (GOSs) is demonstrated under full‐area illumination. The GOSs are composed of partially stacked graphene oxide multilayers formed by a two‐step direct ink writing process. The direction of the photoinduced proton current is determined by the position of top graphene oxide multilayers, which functions as a photogate to modulate the horizontal ion transport through the beneath lamellar nanochannels. This transport phenomenon unveils a new driving mechanism that, in asymmetric nanofluidic structures, the decay of local light intensity in depth direction breaks the balance of electric potential distribution in horizontal direction, and thus generates a photoelectric driving force for ion transport. Following this mechanism, the GOSs are developed into photonic ion transistors with three different gating modes. The asymmetrically printed photonic‐ionic devices provide fundamental elements for light‐harvesting nanofluidic circuits, and may find applications for artificial photosynthesis and artificial electric organs.
Atomically Defined Undercoordinated Active Sites for Highly Efficient CO2 Electroreduction
Authors: Zheng Wanzhen , Yang Jian , Chen Hengquan , Hou Yang , Wang Qi , Gu Meng , He Feng , Xia Ying , Xia Zheng , Li Zhongjian , Yang Bin , Lei Lecheng , Yuan Chris , He Qinggang , Qiu Ming , Feng Xinliang
Published: November 2019

Electrocatalytic reduction of carbon dioxide (CO2ER) in rechargeable Zn–CO2 battery still remains a great challenge. Herein, a highly efficient CO2ER electrocatalyst composed of coordinatively unsaturated single‐atom copper coordinated with nitrogen sites anchored into graphene matrix (Cu–N2/GN) is reported. Benefitting from the unsaturated coordination environment and atomic dispersion, the ultrathin Cu–N2/GN nanosheets exhibit a high CO2ER activity and selectivity for CO production with an onset potential of −0.33 V and the maximum Faradaic efficiency of 81% at a low potential of −0.50 V, superior to the previously reported atomically dispersed Cu–N anchored on carbon materials. Experimental results manifest the highly exposed and atomically dispersed Cu–N2 active sites in graphene framework where the Cu species are coordinated by two N atoms. Theoretical calculations demonstrate that the optimized reaction free energy for Cu–N2 sites to capture CO2 promote the adsorption of CO2 molecules on Cu–N2 sites; meanwhile, the short bond lengths of Cu–N2 sites accelerate the electron transfer from Cu–N2 sites to *CO2, thus efficiently boosting the *COOH generation and CO2ER performance. A designed rechargeable Zn–CO2 battery with Cu–N2/GN nanosheets deliver a peak power density of 0.6 mW cm−2, and the charge process of battery can be driven by natural solar energy.
Complex Hydrides for Energy Storage, Conversion, and Utilization
Authors: He Teng , Cao Hujun , Chen Ping
Published: November 2019

Functional materials are the key enabling factor in the development of clean energy technologies. Materials of particular interest, which are reviewed herein, are a class of hydrogenous compound having the general formula of M(XHn)m, where M is usually a metal cation and X can be Al, B, C, N, O, transition metal (TM), or a mixture of them, which sets up an iono‐covalent or covalent bonding with H. M(XHn)m is generally termed as a complex hydride by the hydrogen storage community. The rich chemistry between H and B/C/N/O/Al/TM allows complex hydrides of diverse composition and electronic configuration, and thus tunable physical and chemical properties, for applications in hydrogen storage, thermal energy storage, ion conduction in electrochemical devices, and catalysis in fuel processing. The recent progress is reviewed here and strategic approaches for the design and optimization of complex hydrides for the abovementioned applications are highlighted.
Built‐In Active Microneedle Patch with Enhanced Autonomous Drug Delivery
Authors: Lopez‐Ramirez Miguel Angel , Soto Fernando , Wang Chao , Rueda Ricardo , Shukla Sourabh , Silva‐Lopez Cristian , Kupor Daniel , McBride David A. , Pokorski Jonathan K. , Nourhani Amir , Steinmetz Nicole F. , Shah Nisarg J. , Wang Joseph
Published: November 2019

The use of microneedles has facilitated the painless localized delivery of drugs across the skin. However, their efficacy has been limited by slow diffusion of molecules and often requires external triggers. Herein, an autonomous and degradable, active microneedle delivery platform is introduced, employing magnesium microparticles loaded within the microneedle patch, as the built‐in engine for deeper and faster intradermal payload delivery. The magnesium particles react with the interstitial fluid, leading to an explosive‐like rapid production of H2 bubbles, providing the necessary force to breach dermal barriers and enhance payload delivery. The release kinetics of active microneedles is evaluated in vitro by measuring the amount of IgG antibody (as a model drug) that passed through phantom tissue and a pigskin barrier. In vivo experiments using a B16F10 mouse melanoma model demonstrate that the active delivery of anti‐CTLA‐4 (a checkpoint inhibitor drug) results in greatly enhanced immune response and significantly longer survival. Moreover, spatially resolved zones of active and passive microneedles allow a combinatorial rapid burst response along with slow, sustained release, respectively. Such versatile and effective autonomous dynamic microneedle delivery technology offers considerable promise for a wide range of therapeutic applications, toward a greatly enhanced outcome, convenience, and cost.
Broadband, Tunable, Miniaturized Vibration Energy Harvester Using Nonlinear Elastomer Beams and Stretchable Interconnects
Authors: Yang Zining , Ismail Nishana , Son ChangHee , Ferreira Placid M. , Kim Seok
Published: November 2019

A miniaturized vibration energy harvester, a small yet sustainable power source that converts ambient mechanical vibration into electricity, is considered as a key technology to advance wireless sensor networks for the internet of things. Conventional chip‐scale vibration energy harvesters, such as microelectromechanical systems devices that are mostly based on rigid materials (e.g., silicon), inherently exhibit high resonant frequency, narrow bandwidth, and a single peak frequency. Therefore, they are often unsuitable for many real‐life applications, as most ambient vibrations have low frequency, broad spectrum, and time variant resonance. Here, an unconventional, soft‐rigid hybrid architecture for vibration energy harvesting, which is inspired by soft electronics, is presented to overcome these limitations. By harnessing soft materials undergoing large deformation, the reported device is designed and tested to demonstrate its energy harvesting performance with high miniaturization, low operation frequency, broadband spectrum, and resonant frequency tuning.
High‐Resolution Inkjet Printing of Quantum Dot Light‐Emitting Microdiode Arrays
Authors: Yang Peihua , Zhang Long , Kang Dong Jin , Strahl Robert , Kraus Tobias
Published: November 2019

The direct printing of microscale quantum dot light‐emitting diodes (QLEDs) is a cost‐effective alternative to the placement of pre‐formed LEDs. The quality of printed QLEDs currently is limited by nonuniformities in droplet formation, wetting, and drying during inkjet printing. Here, optimal ink formulation which can suppress nonuniformities at the pixel and array levels is demonstrated. A solvent mixture is used to tune the ejected droplet size, ensure wetting, and provoke Marangoni flows that prevent coffee stain rings. Arrays of green QLED devices are printed at a resolution of 500 pixels in.−1 with a maximum luminance of ≈3000 cd m−2 and a peak current efficiency of 2.8 cd A−1. The resulting array quality is sufficient to print displays at state‐of‐the‐art resolutions.
Palladium‐Catalyzed ortho‐Benzoylation of Sulfonamides through C−H Activation: Expedient Synthesis of Cyclic N‐Sulfonyl Ketimines
Authors: Ojha Subhadra , Panda Niranjan
Published: November 2019

The ortho‐carbonylation of sulfonylarenes by non‐hazardous aryl aldehydes as a carbonyl precursor was reported. In this method, the sulfonamide group serves as a directing group for C−H activation in the presence of a Pd catalyst under ligand‐free conditions. The scope of this strategy has been extended to the one‐pot two‐step synthesis of cyclic N‐sulfonyl ketimines under mild reaction conditions. Our approach could be considered as an alternative by circumventing the use of highly reactive organolithium or Grignard reagents to access a wide range of biologically potent cyclic N‐sulfonyl ketimines.

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Enhanced Stability of Perovskite Solar Cells Incorporating Dopant‐Free Crystalline Spiro‐OMeTAD Layers by Vacuum Sublimation
Authors: Barranco Angel , Lopez‐Santos Maria C. , Idigoras Jesus , Aparicio Francisco J. , Obrero‐Perez Jose , Lopez‐Flores Victor , Contreras‐Bernal Lidia , Rico Victor , Ferrer Javier , Espinos Juan P. , Borras Ana , Anta Juan A. , Sanchez‐Valencia Juan R.
Published: November 2019

The main handicap still hindering the eventual exploitation of organometal halide perovskite‐based solar cells is their poor stability under prolonged illumination, ambient conditions, and increased temperatures. This article shows for the first time the vacuum processing of the most widely used solid‐state hole conductor (SSHC), i.e., the Spiro‐OMeTAD [2,2′,7,7′‐tetrakis (N,N‐di‐p‐methoxyphenyl‐amine) 9,9′‐spirobifluorene], and how its dopant‐free crystalline formation unprecedently improves perovskite solar cell (PSC) stability under continuous illumination by about two orders of magnitude with respect to the solution‐processed reference and after annealing in air up to 200 °C. It is demonstrated that the control over the temperature of the samples during the vacuum deposition enhances the crystallinity of the SSHC, obtaining a preferential orientation along the π–π stacking direction. These results may represent a milestone toward the full vacuum processing of hybrid organic halide PSCs as well as light‐emitting diodes, with promising impacts on the development of durable devices. The microstructure, purity, and crystallinity of the vacuum sublimated Spiro‐OMeTAD layers are fully elucidated by applying an unparalleled set of complementary characterization techniques, including scanning electron microscopy, X‐ray diffraction, grazing‐incidence small‐angle X‐ray scattering and grazing‐incidence wide‐angle X‐ray scattering, X‐ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy.
Vacancy in Ultrathin 2D Nanomaterials toward Sustainable Energy Application
Authors: Bai Fan , Xu Liang , Zhai Xiaoying , Chen Xu , Yang Wensheng
Published: November 2019

The unique physicochemical properties of (2D) nanomaterials make them well‐suited for use in sustainable energy applications. Many of these materials can be further improved with vacancy engineering. This review details recent progress in the vacancy engineering of ultrathin 2D nanomaterials. For clarity, it mainly focuses on various ultrathin 2D materials in three categories: Xa&XaYb‐, MaXb‐, or MaXbYc‐structured materials. Recently developed vacancies in different types of ultrathin 2D materials, as well as their preparation and characterization, are described. Emphasis is placed on the potential electrochemical energy storage and conversion applications of these materials. This review considers the relationship between vacancy properties and material categories of various ultrathin 2D materials in terms of application requirements, preparation, and characterization techniques. The challenges and future outlook of this promising field are summarized.
Medically actionable comorbidities in adults with Costello syndrome
Authors: Shikany Amy R. , Baker Laura , Stabley Deborah L. , Robbins Katherine , Doyle Daniel , Gripp Karen W. , Weaver K. Nicole
Published: November 2019

Costello syndrome (CS) is an autosomal‐dominant condition caused by activating missense mutations in HRAS. There is little literature describing health concerns specific to adults with CS. Parents of individuals with CS need to know what to anticipate as their children age. We surveyed a group of 20 adults and older adolescents with CS regarding their medical concerns and lifestyle characteristics. We identified several previously undescribed actionable medical concerns in adults with CS. First, the high prevalence of anxiety in this cohort indicates that screening for anxiety is warranted since this is a treatable condition that can have a significant impact on quality of life. Second, adults with CS should be monitored for progressive contractures or other problems that could decrease mobility. This is especially important in a population that seems to have increased risk for osteopenia. Finally, the lack of cancer diagnoses in adulthood is of interest, although the cohort is too small to draw definitive conclusions about cancer risk in adults with CS. Ongoing follow‐up of the current cohort of adults with CS is necessary to delineate progressive medical and physical problems, which is essential for providing targeted management recommendations and anticipatory guidance to families.
The Structure of Sub‐nm Platinum Clusters at Elevated Temperatures
Authors: Henninen Trond R. , Bon Marta , Wang Feng , Passerone Daniele , Erni Rolf
Published: November 2019

Little is known about metallic clusters consisting merely of a dozen of atoms or even less, despite of their importance in catalysis and crystal nucleation. Scanning transmission electron microscopy (STEM) provides direct atomic structure information but has inherently suffered from limited time resolution. We employ fast dynamic STEM combined with a spatio‐temporal image denoising algorithm to explore the structure and stability of Pt clusters on carbon, which represents a highly relevant catalysis system. At room temperature, dynamic amorphous 2D structures are found, while above ≈300 °C, the clusters transform into a crystalline state. Our experimental and theoretical data reveal an unexpected strong trend of the crystalline clusters to exhibit the face‐centered cubic, bulk structure of Pt with cuboidal geometries being most prominent.
Steric Mixed‐Cation 2D Perovskite as a Methylammonium Locker to Stabilize MAPbI3
Authors: Wang Xingtao , Wang Yong , Zhang Taiyang , Liu Xiaomin , Zhao Yixin
Published: November 2019

The reduced dimension perovskite including 2D perovskites are one of the most promising strategies to stabilize lead halide perovskite. A mixed‐cation 2D perovskite based on a steric phenyltrimethylammonium (PTA) cation is presented. The PTA‐MA mixed‐cation 2D perovskite of PTAMAPbI4 can be formed on the surface of MAPbI3 (PTAI‐MAPbI3) by controllable PTAI intercalation by either spin coating or soaking. The PTAMAPbI4 capping layer can not only passivate PTAI‐MAPbI3 perovskite but also act as MA+ locker to inhibit MAI extraction and significantly enhance the stability. The highly stable PTAI‐MAPbI3 based perovskite solar cells exhibit a reproducible photovoltaic performance with a champion PCE of 21.16 %. Such unencapsulated devices retain 93 % of initial efficiency after 500 h continuous illumination. This steric mixed‐cation 2D perovskite as MA+ locker to stabilize the MAPbI3 is a promising strategy to design stable and high‐performance hybrid lead halide perovskites.
Synthesis, Structure, and Reactivity of 5‐(Aryl)dibenzothiophenium Triflates
Authors: Kafuta Kevin , Korzun André , Böhm Marvin , Golz Christopher , Alcarazo Manuel
Published: November 2019

A synthetic protocol for the preparation of 5‐(aryl)dibenzothiophenium salts starting from inexpensive dibenzothiophene S‐oxide and simple arenes is reported. The scope of the method regarding the nature of the arene is evaluated, intermediates along the reaction sequence have been trapped, and side‐reactions identified. In addition, the X‐ray structures of a complete set of these salts are reported and their reactivities studied. Specifically, chemoselective Suzuki coupling is observed at the dibenzothiophenium in the presence of iodides.
Chiral Supramolecular Nanotubes of Single‐Chain Magnets
Authors: Houard Felix , Evrard Quentin , Calvez Guillaume , Suffren Yan , Daiguebonne Carole , Guillou Olivier , Gendron Frédéric , Le Guennic Boris , Guizouarn Thierry , Dorcet Vincent , Mannini Matteo , Bernot Kevin
Published: November 2019

We report a single‐chain magnet (SCM) made of a terbium(III) building block and a nitronyl‐nitroxide radical (NIT) functionalized with an aliphatic chain. This substitution is targeted to induce a long‐range distortion of the polymeric chain and accordingly it gives rise to chains that are curled with almost 20 nm helical pitch. They self‐organize as a chiral tubular superstructure made of 11 chains wound around each other. The supramolecular tubes have a 4.5 nm internal diameter. Overall, this forms a porous chiral network with almost 44 % porosity. Ab initio calculations highlight that each TbIII ion possesses high magnetic anisotropy. Indeed, notwithstanding the supramolecular arrangement each chain behaves as a SCM. Magnetic relaxation with both finite and infinite‐size regimes is observed and confirms the validity of the Ising approximation. This is associated with quite strong coercive field and magnetic remanence (Hc=2400 Oe MR=2.09 μB at 0.5 K) for this class of compounds.
Comparison of the improved processes for amyl acetate synthesis by reactive distillation in different operating modes
Authors: Zhang Qingrui , Liu Yan , Guo Tong , Xu Pengfei , Wang Yujun
Published: November 2019

The application of heat integrated technology can decrease the energy consumption of the reactive distillation process but also increase the coupling degree, which means that the trouble of control is increased. As the improved process of the conventional reactive distillation (CRD) process with excess reactant feed, the design and control of a reactive dividing‐wall column (RDWC) process are explored for synthesizing amyl acetate. The results indicate that the TAC exhibits 12.15% savings compared with the CRD process and robust control is implemented in control schemes CS2 and CS3. In the analysis of the dynamic response results, a novel analytical method is applied, which includes a comprehensive analysis of the vapour flow rate and conversion rate. In addition, the economics and controllability of the two improved processes for synthesizing amyl acetate are compared that involve the different pressure thermally coupled reactive distillation (DPT‐RD) and RDWC processes. The comparison results indicate that the steady‐state economics of the RDWC process are less than those of the DPT‐RD process, but the RDWC process is more applicable industrially in terms of controllability, in which only the tray temperature control is required.
Experimental investigations on spray flames and emissions analysis of diesel and diesel/biodiesel blends for combustion in oxy‐fuel burner
Authors: ElKelawy Medhat , Bastawissi Hagar Alm‐Eldin , El‐Shenawy El‐Shenawy A. , Panchal Hitesh , Sadashivuni Kishorkumar , Ponnamma Deepalekshmi , Al‐Hofy Mahmoud , Thakar Nishant , Walvekar Rashmi
Published: November 2019

Present research work shows the emissions and flame analysis of oxy‐fuel combustion of diesel and diesel/biodiesel blends in the experimental test burner manufactured in Mechanical power engineering laboratory at Tanta University, Egypt. Diesel and a mixture of diesel and biodiesel (B0, B10, B20, B30, and B40) used as a fuel with the effect of pure air and oxy‐combustion. Different emission parameters (carbon monoxide, carbon dioxide, unburned hydrocarbons, NOx, and soot opacity) and the flame parameters (flame cone angle and flame length) were also studied. It has been found that the emission parameters and the flame temperature are higher in diesel fuel than diesel and biodiesel blends for pure air combustion and oxy‐combustion. It has also been found that flame parameters (the flame cone angle and flame penetration length) decreased by adding the oxygen into the charged air and increased by increasing the biodiesel mass percentage. The complete combustion of the fuel blends will dramatically increase the flame temperature due to the presence of a sufficient amount of oxygen for the early chemical reaction between fuel and oxidizer. These results indicated that the biodiesel could be the best alternative as well as an environmentally friendly fuel for diesel engines.
A comparison of coagulation and gelation on the structures and stabilization behaviors of polyacrylonitrile fibers
Authors: Wei Huiqing , Suo Xidong , Lu Chunxiang , Liu Yaodong
Published: November 2019

The fiber spinning methods determine the formation of the physical structures of polyacrylonitrile (PAN) fibers which further affect stabilization reactions and the mechanical performances of the resultant carbon fibers. In this study, PAN fibers were prepared by both dry‐jet gel spinning (g‐PAN) and dry‐jet wet spinning (w‐PAN), and their stabilization behaviors were compared. While the stabilized w‐PAN fibers show sheath‐core structures, the stabilized g‐PAN fibers exhibit relatively uniform stabilized structures along the radial direction. Additionally, the stabilization reactions of g‐PAN fibers occur faster than that of w‐PAN fibers, and the cyclization, oxidation, and crosslinking reaction activation energies of g‐PAN fibers are lower than that of w‐PAN fibers, respectively. Moreover, the carbon yield of g‐PAN is higher than that of w‐PAN fibers. We believe that above changes are possibly ascribed to the formation of different PAN sheath structures and oriented chain structures during dry‐jet wet spinning and dry‐jet gel spinning. It is concluded that gel spinning could significantly reduce the sheath‐core difference of PAN fibers and the stabilized fibers as compared with wet spinning, which leads to a faster stabilization and more uniform stabilized structures. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,137, 48671.
Gular pouch diversity in the Chamaeleonidae
Authors: Huskey Steve , Tegge Samuel M. , Anderson Christopher V. , Smith Michael E. , Barnett Kenneth
Published: November 2019

Numerous chameleon species possess an out‐pocketing of the trachea known as the gular pouch. After surveying more than 250 specimens, representing nine genera and 44 species, we describe two different morphs of the gular pouch. Species of the genera Bradypodion and Chamaeleo, as well as Trioceros goetzei, all possess a single gular pouch (morph one) formed from ventral expansion of soft tissue where the larynx and trachea meet. Furcifer oustaleti and Furcifer verrucosus possess from one to four gular pouches (morph two) formed by the expansion of soft tissue between sequential hyaline cartilage rings of the trachea. In Trioceros melleri, examples of both morphs of the gular pouch were observed. Morphometric data are presented for 100 animals representing eight species previously known to possess a gular pouch and two additional species, Bradypodion thamnobates and Bradypodion transvaalense. In the species with the absolutely and relatively largest gular pouch, Chamaeleo calyptratus, a significant difference was found between sexes in its width and volume, but not its length. In C. calyptratus, we show that an inflated gular pouch is in contact with numerous hyoid muscles and the tongue. Coupled with the knowledge that C. calyptratus generates vibrations from the throat region, we posit that the tongue (M. accelerator linguae and M. hyoglossus) and supporting hyoid muscles (i.e., Mm. sternohyoideus profundus et superficialis and Mm. mandibulohyoideus) are involved in the production of vibrations to produce biotremors that are amplified by the inflated gular pouch and used in substrate‐borne communication.
Microplastics: What Drinking Water Utilities Need to Know
Authors: Smith Emily , Dziewatkoski Michael , Henrie Tarrah , Seidel Chad , Rosen Jeffrey
Published: November 2019

Key Takeaways

Consumers are becoming more concerned with microplastics in water, so utilities should start thinking about methods to identify and address them.

Although there is a lot of research on microplastics in marine environments, there isn't much research yet with drinking water.

To address microplastics, utilities should establish sampling and analytical techniques, identify treatment methods, and implement communications strategies.
Theoretical Soil and Surface Loading Capacity of Buried Copper Tubing
Authors: Frazee Glenn R.
Published: November 2019

Key Takeaways

Two failure modes for buried smooth‐wall steel pipe are described in AWWA Manual M11; it's likely that these failure modes would also apply to buried copper tubing.

This article explores how analysis methods and acceptance criteria for buried steel piping can be used to understand the practical implications for buried copper tubing.

Buried copper tubing for water service typically has a large overburden capacity and for the most part shouldn't require explicit evaluation for soil and surface surcharge.
Evaluating the Catalytic Potential of a General RNA‐Cleaving FANA Enzyme
Authors: Wang Yajun , Vorperian Alexander , Shehabat Mouhamad , Chaput John C.
Published: November 2019

The discovery of synthetic genetic polymers (XNAs) with catalytic activity demonstrates that natural genetic polymers are not unique in their ability to function as enzymes. However, all known examples of in vitro selected XNA enzymes function with lower activity than their natural counterparts, suggesting that XNAs might be limited in their ability to fold into structures with high catalytic activity. To explore this problem, we evaluated the catalytic potential of FANAzyme 12–7, an RNA‐cleaving catalyst composed entirely of 2′‐fluoroarabino nucleic acid (FANA) that was evolved to cleave RNA at a specific phosphodiester bond located between an unpaired guanine and a paired uracil in the substrate recognition arm. Here, we show that this activity extends to chimeric DNA substrates that contain a central riboguanosine (riboG) residue at the cleavage site. Surprisingly, FANAzyme 12–7 rivals known DNAzymes that were previously evolved to cleave chimeric DNA substrates under physiological conditions. These data provide convincing evidence that FANAzyme 12–7 maintains the catalytic potential of equivalent DNAzymes, which has important implications for the evolution of XNA catalysts and their contributions to future applications in synthetic biology.
Oxidative DNA Cleavage with Clip‐Phenanthroline Triplex‐Forming Oligonucleotide Hybrids
Authors: Panattoni Alessandro , El‐Sagheer Afaf H. , Brown Tom , Kellett Andrew , Hocek Michal
Published: November 2019

A systematic study of several new types of hybrids of Cu‐chelated clamped phenanthroline artificial metallonuclease (AMN) with triplex‐forming oligonucleotides (TFO) for sequence‐specific cleavage of double‐stranded DNA (dsDNA) is reported. The synthesis of these AMN–TFO hybrids is based on application of the alkyne–azide cycloaddition click reaction as the key step. The AMN was attached through different linkers at either the 5′‐ or 3′‐ends or in the middle of the TFO stretch. The diverse hybrids efficiently formed triplexes with the target purine‐rich sequence and their copper complexes were studied for their ability to cleave dsDNA in the presence of ascorbate as a reductant. In all cases, the influence of the nature and length of the AMN–TFO, time, conditions and amounts of ascorbate were studied, and optimum conjugates and a procedure that gave reasonably efficient (up to 34 %) cleavage of the target sequence, while rendering an off‐target dsDNA intact, were found. The footprint of cleavage on PAGE was identified only in one case, with low conversion; this means that cleavage does not proceed with single nucleotide precision. On the other hand, these AMN–TFO hybrids are useful for the selective degradation of target dsDNA sequences. Future improvements to this design may provide higher resolution and selectivity.
Taming the Reactivity of Monoterpene Synthases To Guide Regioselective Product Hydroxylation
Authors: Leferink Nicole G. H. , Ranaghan Kara E. , Battye Jaime , Johannissen Linus O. , Hay Sam , van der Kamp Marc W. , Mulholland Adrian J. , Scrutton Nigel S.
Published: November 2019

Monoterpenoids are industrially important natural products with applications in the flavours, fragrances, fuels and pharmaceutical industries. Most monoterpenoids are produced by plants, but recently two bacterial monoterpene synthases have been identified, including a cineole synthase (bCinS). Unlike plant cineole synthases, bCinS is capable of producing nearly pure cineole from geranyl diphosphate in a complex cyclisation cascade that is tightly controlled. Here we have used a multidisciplinary approach to show that Asn305 controls water attack on the α‐terpinyl cation and subsequent cyclisation and deprotonation of the α‐terpineol intermediate, key steps in the cyclisation cascade which direct product formation towards cineole. Mutation of Asn305 results in variants that no longer produce α‐terpineol or cineole. Molecular dynamics simulations revealed that water coordination is disrupted in all variants tested. Quantum mechanics calculations indicate that Asn305 is most likely a (transient) proton acceptor for the final deprotonation step. Our synergistic approach gives unique insight into how a single residue, Asn305, tames the promiscuous chemistry of monoterpene synthase cyclisation cascades. It does this by tightly controlling the final steps in cineole formation catalysed by bCinS to form a single hydroxylated monoterpene product.
Oxidative Dehydrogenation of Cyclohexane by Cu vs Pd Clusters: Selectivity Control by Specific Cluster Dynamics
Authors: Halder Avik , Ha Mai‐Anh , Zhai Huanchen , Yang Bing , Pellin Michael J. , Seifert Sönke , Alexandrova Anastassia N. , Vajda Stefan
Published: November 2019

Supported subnanometer clusters can exhibit catalytic properties not observed in their bulk analogues. Partially‐oxidized Pd and Cu clusters are reported to catalyze the oxidative dehydrogenation of cyclohexane with high activity, and with distinctly different selectivity, producing primarily benzene or cyclohexene, respectively. Under the appliedreaction conditions, the structure and oxidation state of the two catalysts evolve differently, which leads to either the desorption of the cyclohexene intermediate or to its deeper dehydrogenation. Under the applied reaction conditions, the initially oxidized Pd and Cu clusters undergo partial reduction, which we show to be required for the selectivity to emerge. Both systems also have thermal access to multiple distinct structural forms yielding statistical ensembles. The structures within these ensembles evolve with the changing nature of the bound reaction intermediates differently for the two metals; the evolution is found pronounced in the Cu clusters, but only modest in Pd. Ultimately, the different selectivity observed experimentally for the Cu versus Pd clusters is controlled by differences in the collective structural and redox dynamics of their ensembles.
Paper‐Based Microfluidics for Electrochemical Applications
Authors: Shen Liu‐Liu , Zhang Gui‐Rong , Etzold Bastian J. M.
Published: November 2019

Paper‐based microfluidics is characteristic of fluid transportation through spontaneous capillary action of paper and has exhibited great promise for a variety of applications especially for sensing. Furthermore, paper‐based microfluidics enables the design of miniaturized electrochemical devices to be applied in the energy sector, which is especially attractive for the rapid growing market of small size disposable electronics. This review gives a brief summary on the basics of paper chemistry and capillary‐driven microfluidic behavior, and highlights recent advances of paper‐based microfluidics in developing electrochemical sensing devices and miniaturized energy storage/conversion devices. Their structural features, working principles and exemplary applications are comprehensively elaborated and discussed. Additionally, this review also points out the existing challenges and future opportunities of paper‐based microfluidic electronics.
Extending Surface‐Enhanced Raman Spectroscopy to Liquids Using Shell‐Isolated Plasmonic Superstructures
Authors: Wondergem Caterina S. , van Swieten Thomas P. , Geitenbeek Robin G. , Erné Ben H. , Weckhuysen Bert M.
Published: November 2019

Invited for the cover of this issue is the group of Bert M. Weckhuysen at Utrecht University. The image on the cover shows SHIPS, shell‐isolated plasmonic superstructures, detecting the presence of picomoles Rhodamine 6G in an aqueous solution using shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS). Read the full text of the article at 10.1002/chem.2019032004.
Population genetic structure and intraspecific genetic distance of Periplaneta americana (Blattodea: Blattidae) based on mitochondrial and nuclear DNA markers
Authors: Ma Jinnan , Liu Jinhua , Shen Yongmei , Fan Zhenxin , Yue Bisong , Zhang Xiuyue
Published: November 2019

The American cockroach (Periplaneta americana) is a globally invasive pest that can cause significant economic loss and threaten human health. Although it is abundant and lives in close proximity to humans, few studies have investigated the genetic diversity of P. americana. Our study analyzed 1,053 P. americana and other Periplaneta species' samples from different locations in China and the United States. A traditional tree‐based method using 17 unique mitochondrial COI haplotypes of P. americana and 20 haplotypes of the other Periplaneta species accurately identified P. americana with a barcoding threshold of 5.1%. To identify the population genetic structure of P. americana, we investigated wingless gene and pooled them with obtained mtDNA data for a combined analysis. Although the genetic diversity of the USA group was relatively higher than the China group, the number of haplotypes and alleles of both groups was small. The analysis of molecular variance (AMOVA), intraspecific phylogeny, and haplotype networks indicated that P. americana had very little global genetic differentiation. The weak geographic genetic structure might reflect the human‐mediated dispersal of P. americana. Despite no apparent phylogeographic assignment of mtDNA and nuclear lineages was observed in both BI trees, the integrated COI sequence data identified four distinct P. americana haplotype groups, showing four ancient maternal lineages of P. americana in China and the United States.
Perchlorate‐Intercalated Layered Double Hydroxide of Ca and Al: Synthesis, Structure Refinement, and Reversible Dehydration
Authors: Narayanappa Anand N. , Kamath P. Vishnu
Published: November 2019

Hydrocalumite‐like layered double hydroxides are anionic clays comprising positively charged metal hydroxide layers of the composition [Ca2Al(OH)6(H2O)2]+. The water molecules provide the seventh coordination for the Ca2+ ion. Anions are intercalated in the interlayer space to balance the charge leading to a class of LDHs having the formula [Ca2Al(OH)6(H2O)2]·A (A = Cl, Br, I). Upon dehydration the Ca2+ ion gets coordinatively unsaturated, and crystal chemical considerations dictate that the layered structure should collapse. When A = ClO4–, the LDH dehydrates fully below 80 °C, but the layered structure is retained to well over 180 °C. Structure refinement shows that the ClO4– ion in the hydrated phase has one Cl–O bond parallel to the c‐axis, also the stacking direction (molecular symmetry C3v). Upon loss of water, the perchlorate ion not only diffuses to a different position, but also reorients in such way that one of its O atoms directly coordinates with the Ca2+ ion to provide for coordinative saturation of the Ca2+ ion. In the event, the local symmetry of the ClO4– ion is reduced. The hydrated phase is restored on cooling (temperature 27 °C, ambient humidity ca. 50 %).
Trinuclear Nickel(II) and Cobalt(II) Complexes Constructed from Mannich–Schiff‐Base Ligands: Synthesis, Crystal Structures, and Magnetic Properties
Authors: Mocanu Mihaela I. , Patrascu Andrei A. , Hillebrand Mihaela , Shova Sergiu , Lloret Francesc , Julve Miguel , Andruh Marius
Published: November 2019

Trinuclear CoII and NiII complexes have been assembled using an octadentate Mannich–Schiff‐base proligand H2L2 which is obtained by reacting the Mannich base HL1 with propylenediamine (2:1 molar ratio). HL1 is obtained from 5‐bromo‐salicylaldehyde and N,N,N′‐trimethyl‐ethylenediamine. The reaction of H2L2 with nickel(II) and cobalt(II) as nitrate salts affords the trinuclear complexes [Ni3(L2)(NO3)4]·CH3CN (1) and [Co3(L2)(NO3)4]·CH3CN (2) in which the metal ions are bridged by one phenoxido and a nitrato‐oxygen atoms. Within each complex, two of the four nitrato groups act as chelating ligands against the terminal metal ions. The central metal ions in 1 and 2 are hosted into the salen‐like cavity of the organic ligand. The nitrato bridges can be replaced by end‐on azido or end‐on N‐thiocyanato groups leading to the compounds [Ni3(L2)(N3)2(NO3)2] (3), [Co3(L2)(N3)2(NO3)2] (4), and [Co3(L2)(NCS)2(NO3)2]·2CH3CN (5). The magnetic properties of the five compounds have been investigated, revealing the occurrence on intramolecular antiferro‐ (1 and 2) and ferromagnetic interactions (3, 4 and 5). The nature and size of these interactions are discussed and compared to previously reported results on related systems.
New Strategy for the Synthesis of Heterocycles via Copper‐Catalyzed Oxidative Decarboxylative Amination of Glyoxylic Acid
Authors: Niu Bin , Li Shaoqing , Cui Chang , Yan Yizhe , Tang Lin , Wang Jianyong
Published: November 2019

A copper‐catalyzed oxidative decarboxylative amination of glyoxylic acid with substrates having two nitrogen‐nucleophilic sites was first demonstrated. Using this novel approach, 1,3,5‐triazines, quinazolinones and quinazolines were obtained in up to 93 % yields. Notably, glyoxylic acid was employed as the C1 synthon for heterocycles. This strategy enriches the application of glyoxylic acid for the synthesis of valuable heterocycles.
An ANN‐based failure pressure prediction method for buried high‐strength pipes with stray current corrosion defect
Authors: Liu Xiaoben , Xia Mengying , Bolati Dinaer , Liu Jianping , Zheng Qian , Zhang Hong
Published: November 2019

With continued increasing construction of both electrified facilities and buried high‐strength pipelines in China, stray current corrosion defects have become an nonignorable threat for these pipelines. A comprehensive investigation on a new failure pressure prediction model for high‐strength pipes with stray current corrosion defects was conducted in this study. The mechanism of stray current corrosion in steel pipes was firstly elaborated in brief. After that, a parameterized finite element model for stress analysis of pipes with external corrosion defects was programmed by APDL code developed by general software ANSYS. By comparing numerical results with full‐scale experimental results, both the numerical model and the failure criteria for pipe burst were proven to be reasonable. Based on the finite element model, parametric analysis was performed using a calculation matrix set by orthogonal testing method to investigate the effects of three main dimensionless factors, that is, ratio of pipe diameter to wall thickness, nondimensional corrosion defect length, and nondimensional corrosion defect depth on pipe's failure pressure. Utilizing the parametric analysis results as database, a multilayer feed‐forward artificial neural network (ANN) was developed for failure pressure prediction. By comparison with experimental burst test results and results of previous failure pressure estimation model, the ANN model results were proven to have both high accuracy and efficiency, which could be referenced in residual strength or safety assessment of high‐strength pipes with corrosion defects.
Climate risks to Amazon agriculture suggest a rationale to conserve local ecosystems
Authors: Costa Marcos H , Fleck Leonardo C , Cohn Avery S , Abrahão Gabriel M , Brando Paulo M , Coe Michael T , Fu Rong , Lawrence Deborah , Pires Gabrielle F , Pousa Raphael , Soares‐Filho Britaldo S
Published: November 2019

In southern Amazonia, more than half of all cropland is devoted to the production of two rainfed crops per year, an agricultural practice known as “double cropping” (DC). Climate change, including feedbacks between changes in land use and the local climate, is shortening the extent of the historical rainy season in southern Amazonia, increasing the risk of future detrimental environmental conditions, and posing a threat to the intensive DC agriculture that is currently practiced in that region, with potential negative consequences at regional, national, and even global scales. We argue that the conservation of undeveloped forests and savannas in southern Amazonia is supported by socioeconomic justifications and is in the best interests of agribusiness, local governments, and the public.