bluuebunny/crossref_metadata_2025 huggingface dataset:
State‐of‐the‐Art Progress in Diverse Black Phosphorus‐Based Structures: Basic Properties, Synthesis, Stability, Photo‐ and Electrocatalysis‐Driven Energy Conversion
Authors: Gao Wa , Zhou Yong , Wu Xinglong , Shen Qing , Ye Jinhua , Zou Zhigang
Published: September 2020

Over the past few decades, the design and development of advanced catalysts for efficient energy conversion technologies have undergone extensive study. Black phosphorus (BP) is considered to be one of the most promising catalysts, exhibiting remarkable performance and drawing significant attention, because of its extraordinary physicochemical properties: a unique layered structure, anisotropic structure, tunable direct bandgap, and ultrahigh charge mobility. In this review, the fundamentals of bulk BP, single‐ and few‐layer phosphorene, and BP quantum dots are briefly introduced, along with their crystal structure, optical and electrical properties, stability, and synthetic methods. Furthermore, recent progress toward diverse BP‐based materials for photo‐ and electrocatalysis for renewable energy is summarized, specifically focusing on water splitting, CO2 conversion, and nitrogen fixation. Finally, the challenges ahead for these BP‐based catalysts are also emphasized, alongside and perspectives on their further development as part of the this fast‐flourishing renewable energy field.
In Situ Atomic‐Scale Observation of Reversible Potassium Storage in Sb2S3@Carbon Nanowire Anodes
Authors: Cheng Yong , Yao Zhenpeng , Zhang Qiaobao , Chen Jiamin , Ye Weibin , Zhou Shiyuan , Liu Haodong , Wang Ming‐Sheng
Published: September 2020

Antimony trisulfide‐based materials have drawn growing attention as promising anode candidates for potassium‐ion batteries (PIBs) because of their high capacity and good working potential. Despite the extensive investigations on their electrochemical properties, the fundamental reaction mechanisms of Sb2S3 anodes, especially the reaction kinetics, structural changes, and phase evolutions, remain controversial or even largely unknown. Here, using in situ transmission electron microscopy, the entire potassiation–depotassiation cycles of carbon‐coated Sb2S3 single‐crystal nanowires are tracked in real time at the atomic scale. The potassiation of Sb2S3 involves multistep reactions including intercalation, conversion, and two‐step alloying, and the final products are identified as cubic K2S and hexagonal K3Sb. These findings are confirmed by density functional theory calculations. Interestingly, a rocket‐launching‐like nanoparticle growth behavior is observed during alloying reactions, which is driven by the K+ concentration gradient and release of stress. More impressively, the potassiated products (i.e., K3Sb and K2S) can transform into the original Sb2S3 phase during depotassiation, indicating a reversible phase transformation process, as distinct from other metal chalcogenide based electrodes. This work reveals the detailed potassiation/depotassiation mechanisms of Sb2S3‐based anodes and can facilitate the analysis of the mechanisms of other metal chalcogenide anodes in PIBs.
Highly Crystalline Graphene Fibers with Superior Strength and Conductivities by Plasticization Spinning
Authors: Li Peng , Liu Yingjun , Shi Shaoyi , Xu Zhen , Ma Weigang , Wang Ziqiu , Liu Senping , Gao Chao
Published: September 2020

Graphene fiber (GF), a macroscopic one‐dimensional assembly of individual graphene sheets, promises both extraordinary mechanical performance and superior multifunctionality. However, the properties of graphene fiber are still limited due to the unfavorable crystalline structures, especially induced by wrinkled conformations of graphene. A plasticization spinning strategy is presented to achieve GF with both high mechanical strength and electrical/thermal conductivity. Adjusting the interlayer space from 1.2 to 1.8 nm by intercalating proper plasticizers to adjacent graphene oxide sheets enables graphene oxide fibers to achieve a 580% enhanced deformable plasticity. Such a plasticization spinning flattens random graphene wrinkles, and regulates sheets with high order and stacking density, thereby forming large crystallite domains. The GF exhibits all around record performance including mechanical strength (3.4 GPa), electrical conductivity (1.19 × 106 S m−1), and thermal conductivity (1480 W m−1 K−1). The optimally crystalline GF with the integration of benchmark overall properties and scalable fabrication is likely to be attractive and competitive in future industrial applications.
A MXene‐Based Hierarchical Design Enabling Highly Efficient and Stable Solar‐Water Desalination with Good Salt Resistance
Authors: Fan Xiangqian , Yang Yang , Shi Xinlei , Liu Yang , Li Hongpeng , Liang Jiajie , Chen Yongsheng
Published: September 2020

A solar‐thermal water evaporation structure that can continuously generate clean water with high efficiency and good salt rejection ability under sunlight is highly desirable for water desalination, but its realization remains challenging. Here, a hierarchical solar‐absorbing architecture is designed and fabricated, which comprises a 3D MXene microporous skeleton with vertically aligned MXene nanosheets, decorated with vertical arrays of metal–organic framework‐derived 2D carbon nanoplates embedded with cobalt nanoparticles. The rational integration of three categories of photothermal materials enables broadband light absorption, efficient light to heat conversion, low heat loss, rapid water transportation behavior, and much‐improved corrosion and oxidation resistance. Moreover, when assembling with a hydrophobic insulating layer with hydrophilic channel, the MXene‐based solar absorber can exhibit effective inhibition of salt crystallization due to the ability to advect and diffuse concentrated salt back into the water. As a result, when irradiating under one sun, the solar‐vapor conversion efficiency of the MXene‐based hierarchical design can achieve up to ≈93.4%, and can remain over 91% over 100 h to generate clean vapor for stable and continuous water desalination. This strategy opens an avenue for the development of MXene‐based solar absorbers for sustainable solar‐driven desalination.
Prevascularized Scaffolds Bearing Human Dental Pulp Stem Cells for Treating Complete Spinal Cord Injury
Authors: Guo Shaowei , Redenski Idan , Landau Shira , Szklanny Ariel , Merdler Uri , Levenberg Shulamit
Published: September 2020

The regeneration of injured spinal cord is hampered by the lack of vascular supply and neurotrophic support. Transplanting tissue‐engineered constructs with developed vascular networks and neurotrophic factors, and further understanding the pattern of vessel growth in the remodeled spinal cord tissue are greatly desired. To this end, highly vascularized scaffolds embedded with human dental pulp stem cells (DPSCs) are fabricated, which possess paracrine‐mediated angiogenic and neuroregenerative potentials. The potent pro‐angiogenic effect of the prevascularized scaffolds is first demonstrated in a rat femoral bundle model, showing robust vessel growth and blood perfusion induced within these scaffolds postimplantation, as evidenced by laser speckle contrast imaging and 3D microCT dual imaging modalities. More importantly, in a rat complete spinal cord transection model, the implantation of these scaffolds to the injured spinal cords can also promote revascularization, as well as axon regeneration, myelin deposition, and sensory recovery. Furthermore, 3D microCT imaging and novel morphometric analysis on the remodeled spinal cord tissue demonstrate substantial regenerated vessels, more significantly in the sensory tract regions, which correlates with behavioral recovery following prevascularization treatment. Taken together, prevascularized DPSC‐embedded constructs bear angiogenic and neurotrophic potentials, capable of augmenting and modulating SCI repair.
Scalable Fabrication of Molybdenum Disulfide Nanostructures and their Assembly
Authors: Huang Yun , Yu Kang , Li Huaizhi , Xu Kai , Liang Zexi , Walker Debora , Ferreira Paulo , Fischer Peer , Fan Donglei (Emma)
Published: September 2020

Molybdenum disulfide (MoS2) is a multifunctional material that can be used for various applications. In the single‐crystalline form, MoS2 shows superior electronic properties. It is also an exceptionally useful nanomaterial in its polycrystalline form with applications in catalysis, energy storage, water treatment, and gas sensing. Here, the scalable fabrication of longitudinal MoS2 nanostructures, i.e., nanoribbons, and their oxide hybrids with tunable dimensions in a rational and well‐reproducible fashion, is reported. The nanoribbons, obtained at different reaction stages, that is, MoO3, MoS2/MoO2 hybrid, and MoS2, are fully characterized. The growth method presented herein has a high yield and is particularly robust. The MoS2 nanoribbons can readily be removed from its substrate and dispersed in solution. It is shown that functionalized MoS2 nanoribbons can be manipulated in solution and assembled in controlled patterns and directly on microelectrodes with UV‐click‐chemistry. Owing to the high chemical purity and polycrystalline nature, the MoS2 nanostructures demonstrate rapid optoelectronic response to wavelengths from 450 to 750 nm, and successfully remove mercury contaminants from water. The scalable fabrication and manipulation followed by light‐directed assembly of MoS2 nanoribbons, and their unique properties, will be inspiring for device fabrication and applications of the transition metal dichalcogenides.
Highly Sensitive and Selective Sensors for CF4 Gas Molecules Based on Two‐Node Hollow Fullerene
Authors: Zhang Lishu , Li Tao , Feng Yuan Ping , Li Hui , Shen Lei
Published: September 2020

Hollow nanostructures are widely used in chemistry, materials, and bioscience due to their excellent electrochemical and photoelectric properties. Recently, hollow fullerene nanostructures with tailored opening and shapes have been synthesized. Here, the transport properties of two‐node hollow‐fullerene‐based nanoelectronic devices, and their performance are studied for sensing the greenhouse gas molecule, CF4, by density functional theory combined with nonequilibrium Green's function formalism. It is found that such a device has a high sensitivity to CF4 molecules in both dry and humid environments owing to its good selectivity to H2O molecules. The microscopic physics responsible for these fascinating properties are investigated by the transmission spectra, density of states, and voltage drop. This work paves a way to build new functional electronic devices based on the newly discovered hollow nanostructures.
Near‐Field Electrospinning Enabled Highly Sensitive and Anisotropic Strain Sensors
Authors: Huang Yan , You Xiangyu , Fan Xiangyu , Wong Ching Ping , Guo Ping , Zhao Ni
Published: September 2020

The rapid advances in manufacturing technologies have provided great opportunities for scalable fabrication of novel sensing structures and devices. Here, the application of near‐field electrospinning to the fabrication of flexible strain sensors is explored. Through theoretical modeling, it is first verified that a strong anisotropic response of a strain sensor can be obtained through introducing a grid‐shaped design to its sensing layer. Following this guideline, near‐field electrospinning is applied to fabricate polyurethane grids with well‐controlled period and thickness and the grid is further decorated with conductive silver nanowires. Through tuning the structure of the polyurethane grid and the density of the silver nanowires, a high gauge factor (GF = 338.47) under high strain (200%) is achieved, representing the best sensing and stretching property combination reported for flexible strain sensors. In good agreement with the theoretical model, the strain sensors are only sensitive to the strain along the electrode direction and are insensitive to perpendicular direction strains. Based on this characteristic response, the excellent capability of the strain sensors in distinguishing hand movement and monitoring physiological signals is demonstrated, suggesting the great application potential of the sensors in robotic vision and prosthesis.
Metal Island Structure as a Power Booster for High‐Performance Triboelectric Nanogenerators
Authors: Ravichandran Aravind Narain , Ramuz Marc , Blayac Sylvain
Published: September 2020

The development of the Internet of Things requires the availability of compact and efficient power sources for the supply of autonomous systems. In recent times, electromechanical transduction devices like triboelectric nanogenerators (TENGs) have gained strong attention as they permit simple, robust, and cost‐effective techniques. However, TENGs generally do not achieve the electrical power density required for the targeted applications, and the challenges of optimization are therefore to increase their generated power density. In this work, a multilayer flexible composite structure is developed by employing an insulator–metal–insulator island architecture in place of a single insulator material to accumulate and store the charges created by triboelectrification. This increase in stored charges has a strong effect in inducing free charges on the electrodes resulting in a maximum output power density of 4.8 W m−2, which is ≈150‐fold increase compared to the structure without metal inclusions. The results demonstrate a maximum charge density of 1076.56 µC m−2, which is to the knowledge, the best charge density value ever reported for TENGs in ambient working conditions. Therefore, this work proposes a new direction to significantly increase the electrical power density in obtaining high‐performance triboelectric nanogenerators attractive to future applications for active sensors and portable electronics.
Active Membranes on Rigidity Tunable Foundations for Programmable, Rapidly Switchable Adhesion
Authors: Swift Matthew D. , Haverkamp Cole B. , Stabile Christopher J. , Hwang Dohgyu , Plaut Raymond H. , Turner Kevin T. , Dillard David A. , Bartlett Michael D.
Published: September 2020

Rapidly controlling and switching adhesion is necessary for applications in robotic gripping and locomotion, pick and place operations, and transfer printing. However, switchable adhesives often display a binary response (on or off) with a narrow adhesion range, lack post‐fabrication adhesion tunability, or switch slowly due to diffusion‐controlled processes. Here, pneumatically controlled shape and rigidity tuning is coupled to rapidly switch adhesion (≈0.1 s) across a wide range of programmable adhesion forces with measured switching ratios as high as 1300x. The switchable adhesion system introduces an active polydimethylsiloxane membrane supported on a compliant, foam foundation with pressure‐tunable rigidity where positive and negative pneumatic pressure synergistically control contact stiffness and geometry to activate and release adhesion. Energy‐based modeling and finite element computation demonstrate that high adhesion is achieved through a pressure‐dependent, nonlinear stiffness of the foundation, while an inflated shape at positive pressures enables easy release. This approach enables adhesion‐based gripping and material assembly, which is utilized to pick‐and‐release common objects, rough and porous materials, and arrays of elements with a greater than 14 000x range in mass. The robust assembly of diverse components (rigid, soft, flexible) is then demonstrated to create a soft and stretchable electronic device.
Ultrastretchable, Wearable Triboelectric Nanogenerator Based on Sedimented Liquid Metal Elastomer Composite
Authors: Pan Chengfeng , Liu Dongye , Ford Michael J. , Majidi Carmel
Published: September 2020

Progress in soft and stretchable electronics depends on energy sources that are mechanically compliant, elastically deformable, and renewable. Energy harvesting using triboelectric nanogenerators (TENGs) made from soft materials provides a promising approach to address this critical need. Here, an elastomeric composite is introduced with sedimented liquid metal (LM) droplets for TENG‐based energy harvesting that relies on assembly of the LM to form phase‐separated conductive and insulating regions. The sedimented LM elastomer TENG (SLM‐TENG) exhibits ultrahigh stretchability (strain limit > 500% strain), skin‐like compliance (modulus < 60 kPa), reliable device stability (>10 000 cycles), and appreciable electrical output performance (max peak power density = 1 mW cm−2). SLM‐TENGs can be integrated with highly elastic stretchable fabrics, thereby enabling broad integration with wearable electronics. A stretchable and wearable SLM‐TENG is demonstrated that harvests energy from human motion through a patch attached to the knee or integrated into exercise clothing. This body‐mounted TENG device can generate enough electricity to fully power a wearable computing device (hygro‐thermometer with digital display) after 2.2 min of running on a treadmill.
Ynamides in Free Radical Reactions
Authors: Mahe Capucine , Cariou Kevin
Published: September 2020

In this review we present the transformations that have been developed with ynamides and free radicals. These reactions involve carbon‐, heteroatom‐ or even metalloid‐centered radicals and include inter‐ and intra‐molecular reactions. The scope and mechanism of these transformations are discussed in details, including the most recent examples relying on photoredox catalysis.

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Air‐Source Heat Pump for Distributed Steam Generation: A New and Sustainable Solution to Replace Coal‐Fired Boilers in China
Authors: Yan Hongzhi , Hu Bin , Wang Ruzhu
Published: September 2020

With the ratification of the Paris Climate Change Agreement, the use of coal‐fired boilers in China are being gradually restricted and removed from use to control air pollution and reduce CO2 emissions. However, current alternatives to coal‐fired boilers such as gas‐fired boilers, electric boilers, biomass boilers, and solar boilers have obvious limitations and drawbacks that can limit the spread of their use. An air‐source heat pump boiler that can extract thermal energy from air and generate high‐temperature steam is proposed, developed, and verified. The air‐source heat pump boiler shows a stable system output with ambient temperature variations from 5 to 35 °C, with an energy efficiency as high as 150–210% to generate steam at more than 120 °C. Furthermore, by taking technical and economic analysis and carbon trading into consideration, air‐source heat pump boiler has shown significant application advantages than other boilers. This research shows that air‐source heat pump steam generation is feasible for replacing coal‐fired boilers in China and could be a sustainable steam generation method.
Addressable Acoustic Actuation of 3D Printed Soft Robotic Microsystems
Authors: Kaynak Murat , Dirix Pietro , Sakar Mahmut Selman
Published: September 2020

A design, manufacturing, and control methodology is presented for the transduction of ultrasound into frequency‐selective actuation of multibody hydrogel mechanical systems. The modular design of compliant mechanisms is compatible with direct laser writing and the multiple degrees of freedom actuation scheme does not require incorporation of any specific material such as air bubbles. These features pave the way for the development of active scaffolds and soft robotic microsystems from biomaterials with tailored performance and functionality. Finite element analysis and computational fluid dynamics are used to quantitatively predict the performance of acoustically powered hydrogels immersed in fluid and guide the design process. The outcome is the remotely controlled operation of a repertoire of untethered biomanipulation tools including monolithic compound micromachinery with multiple pumps connected to various functional devices. The potential of the presented technology for minimally invasive diagnosis and targeted therapy is demonstrated by a soft microrobot that can on‐demand collect, encapsulate, and process microscopic samples.
Modeling Endothelialized Hepatic Tumor Microtissues for Drug Screening
Authors: Wang Ying , Kankala Ranjith Kumar , Zhang Jianting , Hao Liuzhi , Zhu Kai , Wang Shibin , Zhang Yu Shrike , Chen Aizheng
Published: September 2020

Compared to various traditional 2D approaches, the scaffold‐based 3D tumor models have emerged as an effective strategy to investigate the complex mechanisms behind cancer progression and responses to drug treatments, by providing biomimetic extracellular matrix and stromal‐like microenvironments including the vascular elements. Herein, the development of a 3D endothelialized hepatic tumor microtissue model based on the fusion of multicellular aggregates of human hepatocellular carcinoma cells and human umbilical vein endothelial cells cocultured in poly(lactic‐co‐glycolic acid)‐based porous microspheres (PLGA PMs) is reported. In contrast to the conventional 2D culture, the cells within the PLGA PMs exhibit significantly higher half‐maximal inhibitory concentration values against anticancer drugs, including doxorubicin and cisplatin. Furthermore, the feasibility of coculturing other cell types, such as fibroblasts (L929) and HepG2 cells, is investigated. Together, the findings emphasize the significance of engineered 3D hepatic tumor microtissue models using PLGA PM‐based multicellular aggregates for drug screening applications.
17% Non‐Fullerene Organic Solar Cells with Annealing‐Free Aqueous MoOx
Authors: Tran Hong Nhan , Park Sujung , Wibowo Febrian Tri Adhi , Krishna Narra Vamsi , Kang Ju Hwan , Seo Jung Hwa , Nguyen‐Phu Huy , Jang Sung‐Yeon , Cho Shinuk
Published: September 2020

A charge transport layer based on transition metal‐oxides prepared by an anhydrous sol–gel method normally requires high‐temperature annealing to achieve the desired quality. Although annealing is not a difficult process in the laboratory, it is definitely not a simple process in mass production, such as roll‐to‐roll, because of the inevitable long cooling step that follows. Therefore, the development of an annealing‐free solution‐processable metal‐oxide is essential for the large‐scale commercialization. In this work, a room‐temperature processable annealing‐free “aqueous” MoOx solution is developed and applied in non‐fullerene PBDB‐T‐2F:Y6 solar cells. By adjusting the concentration of water in the sol–gel route, an annealing‐free MoOx with excellent electrical properties is successfully developed. The PBDB‐T‐2F:Y6 solar cell with the general MoOx prepared by the anhydrous sol–gel method shows a low efficiency of 7.7% without annealing. If this anhydrous MoOx is annealed at 200 °C, the efficiency is recovered to 17.1%, which is a normal value typically observed in conventional structure PBDB‐T‐2F:Y6 solar cells. However, without any annealing process, the solar cell with aqueous MoOx exhibits comparable performance of 17.0%. In addition, the solar cell with annealing‐free aqueous MoOx exhibits better performance and stability without high‐temperature annealing compared to the solar cells with PEDOT:PSS.
Climate warming alters photosynthetic responses to elevated CO2 in prairie plants
Authors: Sage Emma , Heisler‐White Jana , Morgan Jack , Pendall Elise , Williams David G.
Published: September 2020

Premise

The impact of elevated CO2 concentration ([CO2]) and climate warming on plant productivity in dryland ecosystems is influenced strongly by soil moisture availability. We predicted that the influence of warming on the stimulation of photosynthesis by elevated [CO2] in prairie plants would operate primarily through direct and indirect effects on soil water.

Methods

We measured light‐saturated photosynthesis (Anet), stomatal conductance (gs), maximum Rubisco carboxylation rate (Vcmax), maximum electron transport capacity (Jmax) and related variables in four C3 plant species in the Prairie Heating and CO2 Enrichment (PHACE) experiment in southeastern Wyoming. Measurements were conducted over two growing seasons that differed in the amount of precipitation and soil moisture content.

Results

Anet in the C3 subshrub Artemisia frigida and the C3 forb Sphaeralcea coccinea was stimulated by elevated [CO2] under ambient and warmed temperature treatments. Warming by itself reduced Anet in all species during the dry year, but stimulated photosynthesis in S. coccinea in the wet year. In contrast, Anet in the C3 grass Pascopyrum smithii was not stimulated by elevated [CO2] or warming under wet or dry conditions. Photosynthetic downregulation under elevated [CO2] in this species countered the potential stimulatory effect under improved water relations. Warming also reduced the magnitude of CO2‐induced down‐regulation in this grass, possibly by sustaining high levels of carbon utilization.

Conclusions

Direct and indirect effects of elevated [CO2] and warming on soil water was an overriding factor influencing patterns of Anet in this semi‐arid temperate grassland, emphasizing the important role of water relations in driving grassland responses to global change.
Understanding the Role of Mental Health Clubhouses in Promoting Wellness and Health Equity Using Pilinahā—An Indigenous Framework for Health
Authors: Agner Joy , Barile John P. , Botero Adriana , Cha Tiffany , Herrera Nikolas , Kaukau Tyra M. , Nakamura Lisa , Inada Megan ,   Hawai‘i Clubhouse Coalition
Published: September 2020

Individuals with severe mental illness need to be engaged in defining their own vision of wellness to promote equity and reduce disparities. This photovoice study helps define what wellness is and how it is achieved in mental health Clubhouses in Hawai‘i. Results from a photovoice study with 43 members and staff were analyzed using Pilinahā, a Native Hawaiian framework for health. Pilinahā envisions health through connection to place, community, past and future, and one’s better self. Within Clubhouses, connection to place included connection to ‘āina (land) and the access to a safe space. Connection to community occurred through reciprocal social support, which developed kuleana (responsibility), and a sense of ‘ohana (family) for many members who were previously isolated. Connection to one’s better self‐involved positive identity change, development of hope, and pursuing opportunities within and outside the Clubhouse. Connection to past and future was described through individual narratives, remembering members who had died, and connection to cultural traditions. Overall, wellness was conceptualized as the ability to work toward dreams, engage in cultural practice, and feel accepted, respected, and valued—to be treated with aloha. Findings provide a culturally responsive perspective on wellness and illustrate the value of Clubhouses as a space for mental health recovery and transformative change.
Skalierbare und wiederverwertbare organische Kolloide als Kaskadenkatalysatoren
Authors: Chen Chen , Janoszka Nicole , Wong Chin Ken , Gramse Christian , Weberskirch Ralf , Gröschel André H.
Published: September 2020

Diese Arbeit beschreibt die tensidfreie Emulsionspolymerisation (SFEP) von Kern‐Schale‐Mikropartikeln (CSM), welche mit einem Säurekatalysator im Kern und einem Basenkatalysator in der Schale ausgestattet sind. Die organokatalytischen Monomere wurden separat über drei Reaktionsschritte eingebaut, wodurch die räumliche Trennung der inkompatiblen sauren und basischen Katalysatoren in den CSM ermöglicht wird. Ein wichtiger Schritt war dabei die Verwendung eines geschützten und thermisch zersetzbaren Sulfonat‐Monomers als Säurequelle, um eine Neutralisation des Basenkatalysators während der Schalenbildung zu vermeiden. Dieser Schritt ist essentiell, um stabile und katalytisch aktive CSM zu erhalten. Die CSM wirken als Kaskadenkatalysatoren und weisen eine hohe katalytische Aktivität auf, die an einer Eintopfkaskadenreaktion untersucht wurden. Die Kaskadenreaktion wurde in verschiedenen Lösungsmitteln (darunter auch Wasser) untersucht und verlief über eine säurenkatalysierte Deacetalisierung gefolgt von einer basenkatalysierten Knoevenagel‐Kondensation. Die CSM können nach der Reaktion leicht zurückgewonnen werden, lassen sich einfach modifizieren und die Synthese ist skalierbar, was sie zu vielversprechenden Kandidaten für organokatalytische Anwendungen macht.
Dual Intramolecular Electron Transfer for In Situ Coreactant‐Embedded Electrochemiluminescence Microimaging of Membrane Protein
Authors: Wang Ningning , Gao Hang , Li Yunzhi , Li Guangming , Chen Weiwei , Jin Zhongchao , Lei Jianping , Wei Qin , Ju Huangxian
Published: September 2020

The demand for transporting coreactant to emitter and short lifetime of the radicals in electrochemiluminescence (ECL) emission inhibit greatly its application in cytosensing and microscopic imaging. Herein we designed a dual intramolecular electron transfer strategy and tertiary amine conjugated polymer dots (TEA‐Pdots) to develop a coreactant‐embedded ECL mechanism and microimaging system. The TEA‐Pdots could produce ECL emission at +1.2 V without need of coreactant in test solution. The superstructure and intramolecular electron transfer led to unprecedented ECL strength, which was 132 and 45 times stronger than those from the mixture of Pdots with TEA at equivalent and 62.5 times higher amounts, respectively. The ECL efficiency was even higher than that of typical [Ru(bpy)3]2+ system. Therefore, this strategy and coreactant‐embedded ECL system could be used for in situ ECL microimaging of membrane protein on single living cells without additional permeable treatment for transporting coreactant. The feasibility and validity were demonstrated by evaluating the specific protein expression on cell surface. This work opens new avenues for ECL applications in single cell analysis and dynamic study of biological events.
Vinylene‐Linked Covalent Organic Frameworks (COFs) with Symmetry‐Tuned Polarity and Photocatalytic Activity
Authors: Xu Junsong , Yang Can , Bi Shuai , Wang Wenyan , He Yafei , Wu Dongqing , Liang Qifeng , Wang Xinchen , Zhang Fan
Published: September 2020

The polarity of a semiconducting molecule affects its intrinsic photophysical properties, which can be tuned by varying the molecular geometry. Herein, we developed aD3h‐symmetric tricyanomesitylene as a new monomer which could be reticulated into a vinylene‐linked covalent organic framework (g‐C54N6‐COF) via Knoevenagel condensation with anotherD3h‐symmetric monomer 2,4,6‐tris(4′‐formyl‐biphenyl‐4‐yl)‐1,3,5‐triazine. Replacing tricyanomesitylene with aC2v‐symmetric 3,5‐dicyano‐2,4,6‐trimethylpyridine gave a less‐symmetric vinylene‐linked COF (g‐C52N6‐COF). The octupolar conjugated characters of g‐C54N6‐COF were reflected in its scarce solvatochromic effects either in ground or excited states, and endowed it with more promising semiconducting behavior as compared with g‐C52N6‐COF, such as enhanced light‐harvesting and excellent photo‐induced charge generation and separation. Along with the matched energy level, g‐C54N6‐COF enabled the two‐half reactions of photocatalytic water splitting with an average O2evolution rate of 51.0 μmol h−1 g−1and H2evolution rate of 2518.9 μmol h−1 g−1. Such values are among the highest of state‐of‐the‐art COF photocatalysts.
Next Generation of Zinc Bisguanidine Polymerization Catalysts towards Highly Crystalline, Biodegradable Polyesters
Authors: Hermann Alina , Hill Stephen , Metz Angela , Heck Joshua , Hoffmann Alexander , Hartmann Laura , Herres‐Pawlis Sonja
Published: September 2020

Polylactide and polycaprolactone are both biodegradable polymers produced through metal‐catalyzed ring‐opening polymerization. For a truly sustainable lifecycle of these polymers it is essential to replace the industrially used cytotoxic catalyst tin(II) bis(2‐ethylhexanoate) [Sn(Oct)2] with non‐toxic alternatives. Here, we report the fastest known robust catalyst in the polymerization of lactide and ϵ‐caprolactone. This zinc guanidine catalyst can polymerize non‐purified technical rac‐lactide and ϵ‐caprolactone in the melt at different [M]/[I] ratios with fast rate constants, high molar masses, and high yields in a short time, leading to colorless, transparent polymer. Moreover, we report that polylactide and polycaprolactone produced by zinc‐guanidine complexes have favorably high crystallinities. In fact, the obtained polylactide shows a more robust degradation profile than its Sn(Oct)2‐catalysed equivalent due to a higher degree of crystallinity.
Photoinduced Aerobic Iodoarene‐Catalyzed Spirocyclization of N‐Oxy‐amides to N‐Fused Spirolactams**
Authors: Habert Loïc , Cariou Kevin
Published: September 2020

Iodoarene catalysis is a powerful methodology that usually requires an excess of oxidant, or of redox mediator if the terminal oxidant is dioxygen, to generate the key hypervalent iodine intermediate to proceed efficiently. We report that, using the spiro‐cyclization of amides as a benchmark reaction, aerobic iodoarene catalysis can be enabled by relying on a pyrylium photocatalyst under blue light irradiation. This unprecedented dual organocatalytic system allows the use of low catalytic loading of both catalysts under very mild operating conditions.
Antimicrobial and biodegradable materials based on ε‐caprolactone derivatives
Authors: Mamba Feziwe Bathabile , Ndlovu Thando , Mbizana Siyasanga , Khan Wesaal , Gule Nonjabulo Prudence
Published: September 2020

Appropriate wound care is pivotal in preventing wound and postsurgery infections, which remain a serious clinical problem. In this study, we report the successful fabrication of antimicrobial and biodegradable materials for possible use in the medical field. Amino functionalized polycaprolactone (PCL [Poly(CL‐co‐ACL)]) was synthesized via ring opening polymerization. This polymer was then functionalized via the pendant amine to induce antimicrobial efficacy. This was done through the grafting of poly(lysine) onto the amine as well as the quaternization of the amine using alkyl halides. The chemical structures of the synthesized monomers and polymers were confirmed using nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopy and attenuated total reflection‐Fourier transform infrared spectroscopy. The molecular weights of the polymers were determined using gel permeation chromatography. Nanofibre scaffolds were produced from the polymers using the electrospinning technique and these were characterized though scanning electron microscopy. The antimicrobial efficacy of the fabricated materials was tested against the Gram‐positive (Staphylococcus aureus ATCC 25923) and Gram‐negative (Pseudomonas aeruginosa ATCC 27853) bacteria using the disc diffusion and shake flask methods. The polymers demonstrated excellent antimicrobial efficacy. The fibers were exceptionally biodegradable which opens a lot of applications in the biomedical space.
“Poly (sulfur/oil) impregnated cotton: A newly developed material for effective oil removal from contaminated water”
Authors: Bajpai Sunil Kumar , Dubey Deepika
Published: September 2020

In this work, a unique material has been developed by carrying out in situ co‐polymerization of sulfur and triglycerides (edible oil) within the cotton fibers to yield poly (sulfur/oil) impregnated cotton (PSOIC) composite material. The adsorbent was characterized by Fourier transform infrared, X‐ray diffraction, and SEM analysis. The equilibrium oil uptake studies were carried out in batch mode experiments and the sorption data were analyzed by various sorption isotherm models. The Langmuir model was found to be best fitted with maximum oil sorption capacity Qo of 9.52 g/g polymer. On the contrary, the conventional poly (sulfur/oil) adsorbent showed a Qo value of 2.35 g/g polymer, thus indicating the suitability and superiority of PSOIC over PSO material. The newly developed PSOIC material could be pressed in the form of sheets and was successful in removing oil/grease layer from the oil/water mixture. The adsorbent showed fair re‐generation capacity, thus minimizing the cost effectiveness to employ in large‐scale removal processes.
The effect of degree of polymerization on the structure and properties of polyvinyl alcohol fibers with high strength and high modulus
Authors: Hong Xinqiu , Xu Yongjing , Zou Liming , Li Yan Vivian , He Junwei , Zhao Jiongxin
Published: September 2020

Polyvinyl alcohol (PVA) fibers were prepared using PVA with different degree of polymerization (DP) under the same wet spinning process. The effect of the DP of PVA on the structures and properties of PVA and PVA fibers were studied by using nuclear magnetic resonance hydrogen spectroscopy (1H‐NMR), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), differential scanning calorimeter (DSC), thermo gravimetric analysis (TGA), and environmental scanning electron microscope (ESEM). The results showed that DP had little effect on the crystallinity and tacticity of PVA, but had a positive effect on melting temperature, and initial decomposition temperature of PVAs. The hot drawing ratio determined by the spinning process where the PVA fibers could be continuously collected without breaking. The drawing ratio was decreased with an increase of DP, resulting in an increase of the final fiber diameter. The PVA fibers with medium DP and medium size demonstrated high strength and high modulus, but relatively low breaking elongation. It suggested that high DP of PVA was not a guarantee of high strength and high modulus PVA fibers, but rather a primary structure factor. The fiber performance was determined by a comprehensive effect combining a variety of factors including polymer properties and spinning conditions. It provided a guideline for PVA fiber manufacture that the PVAs with different DP require different spinning processes to obtain optimal fiber performance.
Publish, then perish? Five years on, sawfishes are still at risk in Bangladesh
Authors: Haque Alifa Bintha , Leeney Ruth H. , Biswas Aparna Riti
Published: September 2020

Sawfishes are highly threatened globally, and current data on their conservation status in the Indian Ocean are limited. A baseline study conducted in 2011–2012 revealed that at least two species of sawfish were still present in Bangladeshi waters and highlighted several important steps that could be taken to prevent populations from further decline.

Regular visits to landing sites in the south‐eastern coastal region of Bangladesh were conducted to collect data on sawfish landings. A telephone reporting system was developed amongst shark traders and fishers, to facilitate immediate reporting of sawfish landings.

Between 15 October 2016 and 26 December 2017, landings of 25 sawfishes were documented, of which at least 17 were largetooth sawfish Pristis pristis. No evidence of narrow sawfish Anoxypristis cuspidata was observed, which may suggest that this species has become rare.

These data were collected 5 years after the baseline study was conducted and after several years of broader efforts to highlight the precarious status of sawfish populations globally. The findings illustrate that largetooth sawfish continue to be landed and that none of the management or community engagement activities previously recommended, in order to reduce catch rates, have been implemented.

This is an example of the research–practitioner divide, where published scientific research on a group of highly endangered elasmobranchs has not led to their protection. A strategy for communicating the findings of this study and the critical need for local conservation action for sawfishes to key national and local stakeholders is presented, alongside a suite of actions that can be feasibly implemented in the next 12 months.
The Longitudinal Immune Response to Coronavirus Disease 2019: Chasing the Cytokine Storm
Authors: Chau Alice S. , Weber Andrew G. , Maria Naomi I. , Narain Sonali , Liu Audrey , Hajizadeh Negin , Malhotra Prashant , Bloom Ona , Marder Galina , Kaplan Blanka
Published: September 2020

The clinical progression of the severe acute respiratory syndrome coronavirus 2 infection, coronavirus 2019 (COVID‐19), to critical illness is associated with an exaggerated immune response, leading to magnified inflammation termed the “cytokine storm.” This response is thought to contribute to the pathogenicity of severe COVID‐19. There is an initial weak interferon response and macrophage activation that results in delayed neutrophil recruitment leading to impeded viral clearance. This causes prolonged immune stimulation and the release of proinflammatory cytokines. Elevated inflammatory markers in COVID‐19 (e.g., d‐dimer, C‐reactive protein, lactate dehydrogenase, ferritin, and interleukin‐6) are reminiscent of the cytokine storm seen in severe hyperinflammatory macrophage disorders. The dysfunctional immune response in COVID‐19 also includes lymphopenia, reduced T cells, reduced natural killer cell maturation, and unmitigated plasmablast proliferation causing aberrant IgG levels. The progression to severe disease is accompanied by endotheliopathy, immunothrombosis, and hypercoagulability. Thus, both parts of the immune system—innate and adaptive—play a significant role in the cytokine storm, multiorgan dysfunction, and coagulopathy. This review highlights the importance of understanding the immunologic mechanisms of COVID‐19 as they inform the clinical presentation and advise potential therapeutic targets.
Hydrothermal Synthesis of Carbon Nano‐Onions from Citric Acid
Authors: Sang Song , Yang Sheng , Guo Aoping , Gao Xiang , Wang Yangyang , Zhang Ce , Cui Fangming , Yang Xiaojing
Published: September 2020

Carbon nano‐onions with concentric fullerene‐like carbon shells were synthesized by hydrothermal carbonization of citric acids at 180 °C and formed through the intermediates of graphene quantum dots, graphitic nano‐sheets and graphitic hollow polyhedrons. The graphene quantum dots were firstly formed by the dehydration of citric acids and then grew and stacked into graphitic nano‐sheets, which curved into graphitic hollow polyhedrons due to the interface energy. The graphitic hollow polyhedrons eventually transformed into spherical carbon nano‐onions with the lowest interface energy in the hydrothermal solution by disordering and rearrangement of the carbon shell.
Observing Visual Attention and Writing Behaviors During a Writing Assessment: Comparing Children with Autism Spectrum Disorder to Peers with Attention‐Deficit/Hyperactivity Disorder and Typically Developing Peers
Authors: Zajic Matthew Carl , Solari Emily Jane , McIntyre Nancy Susan , Lerro Lindsay , Mundy Peter Clive
Published: September 2020

Children with autism spectrum disorder (ASD) demonstrate heterogeneous writing skills that are generally lower than their typically developing (TD) peers and similar to peers with attention difficulties like attention‐deficit/hyperactivity disorder (ADHD). Recent evidence suggests children with ASD spend less time engaging in writing tasks compared to their peers, but previous studies have not examined engagement specifically within the writing task environment. This study used video observation data collected from 121 school‐age children (60 children with ASD, 32 children with ADHD, and 29 TD children) to compare differences in visual attention and writing task behaviors and relationships between task behaviors and age, cognitive skills, and ASD and ADHD symptom severity. Findings indicated that groups mostly spent time looking at and writing on the draft, though this was lowest in the ASD group. No differences were found between the ASD and ADHD groups after accounting for task behavior durations as percentages of total used task time. Groups spent little time looking at their outlines and looking away from the task, with all groups spending relatively more time looking at the task picture. Time spent engaged with the draft showed a positive relationship with writing performance across groups, but a negative relationship between time spent looking at the task picture and writing performance only appeared for the ADHD group. The ASD and ADHD groups showed negative associations between draft engagement and ASD symptom severity but not ADHD symptom severity. Implications are discussed for understanding writing task engagement in research and instructional contexts.

Lay Summary

Children with autism spectrum disorder (ASD) demonstrate variable writing skills. Here, we examine how children with ASD engage during a writing task by using video observation data to compare their engagement to peers with and without attention difficulties. Findings indicate (a) lower draft engagement and similar task disengagement in children with ASD compared to their peers and (b) moderate‐to‐strong relationships between writing scores and ASD symptom severity with within‐task engagement in children with ASD and their peers with attention difficulties.
Design of Site‐Specific Microwave Phased Array Hyperthermia Applicators Using 434 MHz Reduced Cavity‐Backed Patch Antenna
Authors: Baskaran Divya , Arunachalam Kavitha
Published: September 2020

Cancers of the neck, breast, and lower extremities are common malignancies diagnosed in India with a higher incidence of advanced‐stage disease. Phased array (PA) applicators reported for hyperthermia treatment (HT) of the breast have small focal region and high cross‐coupling, and those reported for lower extremities provide regional heating and limited steering. In this study, we present the numerical design of site‐specific PA applicators for HT of large solid tumors in the neck, breast, and lower extremities using a miniaturized 434 MHz cavity‐backed water‐loaded patch antenna. The fabricated antenna has 38 × 36 mm2 aperture, more than 90% power coupling, 25 MHz bandwidth, and good agreement between simulated and measured specific absorption rate (SAR) in phantom. The site‐specific applicators demonstrated less power reflection (<−17.9 dB) and cross‐coupling (<−26.8 dB) for 5 mm inter‐ring spacing. SAR indicators for 64 cc tumor at varying locations in simplified layered three‐dimensional (3D) tissue models of the neck, breast, and leg showed average power absorption ratio (aPAratio) ≥ 3.16, target to hotspot quotient (THQ) ≥ 0.57, 25% iso‐SAR coverage (TC25) ≥ 81%, and 50% iso‐SAR coverage (TC50) ≥51.8%. Simulation results of site‐specific applicators for 3D inhomogeneous patient models showed aPAratio ≥ 5.98, THQ ≥ 0.9, TC50 ≥ 86%, and 100% TC25 for all sites. It is concluded that the 434 MHz miniaturized cavity‐backed patch antenna can be used to develop high‐density PA applicators with 12–24 antennas for HT of large solid tumors (≥4 cm) in the neck, breast, and lower extremities with 3D steering ability and less cross‐coupling (≤−26.8 dB). © 2020 Bioelectromagnetics Society
Logics, rhetoric and ‘the blob’: Populist logic in the Conservative reforms to English schooling
Authors: Craske James
Published: September 2020

A lot has been written about the lasting implications of the Conservative reforms to English schooling, particularly changes made by Michael Gove as Education Secretary (2010–2014). There is a lot less work, however, on studying the role that language, strategy and the broader political framework played in the process of instituting and winning consent for these reforms. Studying these factors is important for ensuring that any changes to education and schooling are not read in isolation from their political context. Speeches particularly capture moments where intellectual and strategic political traditions meet, helping us to form a richer understanding of the motives behind specific reform goals and where they fit into a political landscape. This article analyses speeches and policy documents from prominent politicians who led the Conservative education agenda between 2010–2014 to illustrate how politicians mobilised a deliberate populist strategy and argumentation to achieve specific educational goals, but which have had broader social and political implications. Concepts from interpretive political studies are used to develop a case analysis of changes to teacher training provision and curriculum reform, illustrating how politicians constructed a frontier between ‘the people’ (commonly teachers or parents) and an illegitimate ‘elite’ (an educational establishment) that opposed change. This anti‐elite populist rhetoric, arguably first tested in the Department for Education, has now become instituted more widely in our current British politics.