bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Performances of CVD‐Grown MoS2 Based Phototransistors Enabled by Encapsulation
Authors: Yang Yujue , Liu Zihao , Shu Kaixiang , Li Ling , Li Jingbo
Published: May 2021

MoS2 as a semiconducting 2D material has been a promising candidate for the next generation of optoelectronics due to its atomic thickness, mechanical flexibility, complementary metal‐oxide‐semiconductor compatibility, and large‐scale manufacturing. However, the poor quality such as low mobility and numerous defects has much affected the corresponding device performances, which has limited their wide applications. Here, an effective strategy is proposed to significantly improve the quality of the chemical vapor deposition (CVD)‐grown monolayer MoS2 by the encapsulation technique with atomic layer deposition Al2O3. Benefiting from the passivation of defects and suppression of charge Coulomb scattering, the mobility can be improved by more than one order of magnitude, reaching up to 62.5 cm2 Vs−1. As a result, the photodetection performances in terms of response time, responsivity, and detectivity are also improved up to 20 ms, 1.1 × 104 A W−1, and 3.1 × 1012 Jones, respectively. The developed encapsulation technique here for the improvement of film quality and device performance can further enable the practical application of large‐scale 2D materials‐based electronics and photodetectors.
Enhanced Electromechanical Response and Thermal Stability of 0.93(Na1/2Bi1/2)TiO3‐0.07BaTiO3 Through Aerosol Deposition of Base Metal Electrodes
Authors: Khansur Neamul H. , Eckstein Udo , Ursic Hana , Sadl Matej , Brehl Martin , Martin Alexander , Riess Kevin , de Ligny Dominique , Webber Kyle G.
Published: May 2021

Na1/2Bi1/2TiO3‐based relaxor ferroelectrics are extensively investigated for use in transduction applications because of their relatively large electromechanical properties. Integration of these materials into devices, however, requires better temperature stability in addition to electromechanical properties. This work demonstrates a novel approach to enhance the temperature stability of the long‐range ferroelectric order as well as to enhance electromechanical properties in a non‐ergodic relaxor 0.93(Na1/2Bi1/2)TiO3‐0.07BaTiO3 (NBT‐7BT) without changing the chemical composition through, for example, chemical substitutions or second phase particles. The approach involves the room temperature deposition of copper electrodes directly on the relaxor ceramic substrate using the aerosol deposition (AD) method. The collision of solid‐state particles with the substrate surface during AD results in large impact and residual stresses, inherent to the AD process, which are shown with piezo‐response force microscopy to induce long‐range ferroelectric domain ordering in non‐ergodic relaxor NBT‐7BT. Using Raman spectroscopy, the magnitude and depth profile of the stress‐induced transformation are determined. It is demonstrated that deposition‐induced stresses significantly increase the temperature stability of the electromechanical properties, where long‐range ferroelectric ordering is observed up to 150 °C, which is approximately 41 °C higher than NBT‐7BT samples without the AD processed electrode. Moreover, the AD treatment also facilitates ferroelectric domain switching at a lower electric field, enabling maximum polarization at a relatively lower field and an enhancement in the piezoelectric response. It is shown that the deposition‐induced stress is responsible for such an enhancement. Importantly, this impact‐stress‐driven tailoring of electromechanical properties can potentially be utilized for other functional ceramic materials as well, where internal residual stress can result in enhanced functional properties.
Design Artificial Stem Cell Nests for Stem Cell Niche in a Microfluidic Petri Dish Programmed by a Cell Phone
Authors: Peng Xing Yue (Larry) , Guo Yaxin , Peng Linghan , Liu Juan
Published: May 2021

This article describes a technology to transform a petri dish into a microfluidic chip with a stem cell nest for stem cell niche engineering. A permanent magnet sphere is put in a 30 mm petri dish as an oscillator pump (O‐pump). An earphone‐sized actuator outside the petri dish receives the programmed audio signal from an MP3 player or a mobile phone to drive the in‐dish O‐pump for a microflow. There are guiding walls to form a wake area for the cell nest at the dish's center. The cell nest uses the wake to create a stable, ultraslow internal microcirculation flow. The retention half‐life of nanoparticles in the cell nest is 1419.8 ± 1.3 s. By setting the microfluidic program and supplementing five drops of the culture medium outside the cell nest every 2 d, the growth rate of embryonic stem cells in the cell nest during the 8 d automatic culture appears significantly optimized. The single clone area of embryonic stem cells increases from (3.57 ± 0.52) × 105 to (11.67 ± 1.33) × 105  µm2  after 2 d of the automatic culture and advances to (53.34 ± 8.37) × 105  µm2 after 4 d.
High‐Performance Hybrid White OLEDs with Ultra‐Stable Emission Color and Small Efficiency Roll‐Off Achieved by Incorporating a Deep‐Blue Fluorescent Neat Film
Authors: Wu Zilong , Zhu Xiangyu , Li Yinghao , Chen Hao , Zhuang Zeyan , Shen Pingchuan , Zeng Jiajie , Chi Jiajin , Ma Dongge , Zhao Zujin , Tang Ben Zhong
Published: May 2021

Organic blue luminescent materials play a vital role in the fabrication of full‐color displays and white lighting devices, but high‐efficiency blue emitters that meet commercial demands are still quite insufficient. Herein, the authors wish to report the design and synthesis of four bipolar deep‐blue luminogens consisting of an anthracene core and various functional groups. Their photophysical properties, electronic structures, electrochemical behavior, thermal stability, carrier transport ability, and electroluminescence performance are systematically studied. The nondoped organic light‐emitting diode (OLED) based on DPAC‐TAn‐BI radiates stable deep‐blue light [Commission Internationale de l'Eclairage (CIEx,y) = 0.15, 0.15] with a high external quantum efficiency (ηext) of 5.81%. Moreover, efficient two‐color hybrid warm white OLEDs are achieved using DPAC‐TAn‐BI neat film as a blue‐emitting layer, providing an excellent ηext of 27.6%, a small efficiency roll‐off of 2.9% at 1000 cd m−2, and ultra‐stable emission spectra with tiny CIEx,y variation of (0.01, 0.01) from 100 to 10 000 cd m−2. These results demonstrate that the deep‐blue luminogens are strong candidates for applications in blue and white OLEDs.
mOptical Sensing for the Internet of Things: A Smartphone‐Controlled Platform for Temperature Monitoring
Authors: Ramalho João F. C. B. , Carlos Luís D. , André Paulo S. , Ferreira Rute A. S.
Published: May 2021

Sensors play a key role on the Internet of Things (IoT), providing monitoring inside and outside the networks in a multitude of parameters. A fundamental parameter to sense is temperature, being essential to acquire knowledge on the best way to include thermal sensing into the communications networks. Despite that the temperature measurement in the optical domain is well known for its advantages compared with the electric one, its incorporation in the IoT is a challenge due to the lack of affordable strategies able to convert optical into an electronic signal in a cost‐effective way. The coupling of such optical sensors to smartphones appears as an exciting strategy for mobile optical (mOptical) sensing. Herein, advances in optical temperature sensors for mOptical sensing are reviewed and the chronological mechanistic context of waveguided and nonguided optical signal sensors is outlined. A new path for advances in photonics research is traced, established by the incorporation of smartphones as a tool in science and engineering that foresees new designs for mOptical temperature sensor toward IoT.
Palladium‐Catalyzed Heck/Insertion/Decarboxylation Domino Sequence: Synthesis of Dihydrocyclohepta[de]naphthalenes
Authors: He Cai , Chen Xiang‐Long , Zhuang Shi‐Yi , Wu Yan‐Dong , Tang Bo‐Cheng , Wu An‐Xin
Published: May 2021

A Pd‐catalyzed cascade cyclization for the construction of fused dihydrocyclohepta[de]naphthalene skeletons was developed. The skeleton was assembled from 3‐iodo‐4H‐chromen‐4‐one, norbornene and 8‐bromo‐1‐naphthoic acid. Unlike the classic Catellani reaction, which involves the removal of norbornene, in the present system, norbornene acts as a building block for the construction of rigid nonplanar molecular architectures rather than as an ortho‐directing transient mediator. This synthesis involves the formation of three C−C bonds via a one‐pot process, and it is compatible of a series of substituents.

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Impact of Crystalline and Amorphous Matrices on Successful Spray Drying of siRNA Polyplexes for Inhalation of Nano‐in‐Microparticles
Authors: Keil Tobias W. M. , Zimmermann Christoph , Baldassi Domizia , Adams Friederike , Friess Wolfgang , Mehta Aditi , Merkel Olivia M.
Published: May 2021

To develop stable and inhalable dry powder formulations with long shelf life, polyplexes consisting of siRNA and a polyethylenimine (PEI)‐based block copolymer in presence of mannitol or trehalose are spray dried. The effect of inlet (T‐In) and outlet (T‐Out) temperature on the recovery of siRNA and adsorption effects within the tubing material are investigated. Choosing a low abrasion silicon tubing prevented siRNA loss due to adsorption. Mannitol and trehalose formulations preserved siRNA integrity regardless of excipient concentration and temperature at T‐Out below the siRNA melting temperature. Trehalose formulations allowed full siRNA recovery whereas mannitol formulations resulted in spray drying induced losses of ≈20% siRNA and of 50–60% polymer. Mannitol formulations showed optimal aerodynamic characteristics as confirmed by next generation impaction analysis based upon siRNA content. All spray dried formulations resulted in green fluorescent protein (GFP) silencing comparable or better than freshly prepared polyplexes. To test if the observed results could be transferred, formulations of siRNA and transferrin‐PEI conjugates are spray dried, characterized, and used to transfect primary human T cells ex vivo. Results confirmed successful silencing of the transcription factor GATA3 in primary CD4+ T cells with spray dried formulations as a potential treatment for severe asthma.
Tuning Pressure Drop in Isoporous Membranes: Design with Fabrication Variability
Authors: Ong Shi Ke , Birgersson Erik , Low Hong Yee
Published: May 2021

Isoporous membranes consist of well‐defined micro and nanoscale pore architecture comprising uniform pore sizes with straight pore channels. In contrast to traditional random porous membranes with tortuous flow paths, isoporous membranes offer the opportunity to achieve a high degree of membrane customization and low pressure drop. Here, a physics‐based machine learning methodology that enables the predictive design of a single‐layer isoporous membrane in terms of the pressure drop is reported. In short, the methodology consists of a hybrid approach that includes experimental data on the variability of the pore architecture and the resulting pressure drop, training of a neural network with data from validated physics‐based simulations of laminar flow through the membrane, and Monte Carlo simulation (MCS) to stochastically account for the inherent variabilities of the pore architecture of fabricated isoporous membranes. Overall, the neural network and MCS predict the range of Δp for a given single‐layer membrane well. Experimental values fall within 90% of the minimum and maximum predicted Δp values. In addition, a sensitivity analysis with MCS is carried out to quantify how design and operating parameters affect the overall pressure drop. The methodology can be extended to membranes comprising multiple layers and to account for filtration efficiency.
Unparalleled Armour for Aramid Fiber with Excellent UV Resistance in Extreme Environment
Authors: Chen Fengxiang , Zhai Lisha , Yang Huiyu , Zhao Shichao , Wang Zonglei , Gao Chong , Zhou Jingyi , Liu Xin , Yu Zhenwei , Qin Yong , Xu Weilin
Published: May 2021

Aramid fibers are widely used in many cutting‐edge fields, including space, aviation, military, and electronics. However, their poor UV resistance and surface inertness seriously hinder their utilization, especially in harsh environments. Here, a dual‐layer ultrathin Al2O3–TiO2 coating with a thickness of 70–180 nm is fabricated on aramid fibers by a modified atomic layer deposition (ALD) method. The tenacity of ALD‐coated aramid fibers decreases only by ≈0.85% after exposure to intense UV light (4260 W m−2) under high temperature (>200 ℃) for 90 min, which equals to continuous exposure to sunlight for about 17 500 days. The as‐prepared aramid fibers also show excellent laundering durability, thermal and chemical stabilities. This work presents a green and damage‐free approach to achieve the highly anti‐UV aramid fibers without sacrificing their outstanding performance, which is expected to guide material design for future innovations in functional fibers and devices.
Dual‐Metal Sites Boosting Polarization of Nitrogen Molecules for Efficient Nitrogen Photofixation
Authors: Zhang Yida , Hou Tingting , Xu Quan , Wang Qingyu , Bai Yu , Yang Shaokang , Rao Dewei , Wu Lihui , Pan Haibin , Chen Jiafu , Wang Gongming , Zhu Junfa , Yao Tao , Zheng Xusheng
Published: May 2021

Constructing nitrogen (N2) adsorption and activation sites on semiconductors is the key to achieving efficient N2 photofixation. Herein, Mn–W dual‐metal sites on WO3 are designed toward efficient N2 photoreduction via controlled Mn doping. Impressively, the optimal 2.3% Mn‐doped WO3 (Mn‐WO3) exhibits a remarkable ammonia (NH3) production rate of 425 µmol gcat.−1 h−1, representing the best catalytic performance among the ever‐reported tungsten oxide‐based photocatalysts for N2 fixation. Quasi in situ synchrotron radiation X‐ray spectroscopy directly identifies that the Mn–W dual‐metal sites can enhance the polarization of the adsorbed N2, which is beneficial to the N2 activation. Further theoretical calculations reveal that the increased polarization is originated from the electron back‐donation into the antibonding orbitals of the adsorbed N2, hence lowering the reaction energy barrier toward the N2 photofixation. The concept of dual sites construction for inert molecule activation offers a powerful platform toward rational design of highly efficient catalysts for nitrogen fixation and beyond.
Quantifying the Plasmonic Generation Rate of Non‐Thermal Hot Carriers with an AlGaN/GaN High‐Electron‐Mobility Transistor
Authors: Li Chun‐Yu , Liu Chi‐Ching , Lai Wei‐Chih , Lan Yung‐Chiang , Chang Yun‐Chorng
Published: May 2021

Plasmonic generation of hot carriers in metallic nanostructures has attracted much attention due to its great potential in several applications. However, it is highly debated whether the enhancement is due to the hot carriers or the thermal effect. Here, the ability to exclude the thermal effect and detect the generation of non‐thermal hot carriers by surface plasmon is demonstrated using an AlGaN/GaN high‐electron‐mobility transistor. This ultrasensitive platform, which demonstrates at least two orders of magnitude more sensitivity compared to the previous reports, can detect the hot carriers generated from discrete nanostructures illuminated by a continuous wave light. The quantitative measurements of hot carrier generation also open a new way to optimize the plasmonic nanoantenna design in many applications.
Defect Engineering for Expediting Li–S Chemistry: Strategies, Mechanisms, and Perspectives
Authors: Shi Zixiong , Li Matthew , Sun Jingyu , Chen Zhongwei
Published: May 2021

Lithium–sulfur (Li–S) batteries have stimulated a burgeoning scientific and industrial interest owing to high energy density and low materials costs. The favorable reaction kinetics of sulfur species is a key prerequisite for pursuing their commercialization. Recent years have witnessed a wealth of investigations in terms of boosting sulfur redox via rationalizing redox mediators. Defect engineering, which allows for the effective exposure of active sites and optimization of electronic structure, has emerged expeditiously as an essential strategy to enhance polysulfide modulation, and hence expedite Li–S chemistry. Nevertheless, a comprehensive overview of defect engineering in Li–S realm is still lacking. This review emphasizes the recent advances in the rational design and polysulfide modulation strategies of different types of defective mediators. Their unique morphological configuration, superb electrochemical activity, and underlying catalytic mechanism are comprehensively summarized, aiming to deepen the understanding of defect‐mediated Li–S chemistry. Moreover, in situ evolution of defective mediators is discussed to identify the true active sites under aprotic reaction conditions. Opportunities and an outlook of this fast‐developing frontier that may lead to practical implementations of Li–S batteries are proposed.
Revealing the Impact of Hierarchical Pore Organization in Supercapacitor Electrodes by Coupling Ionic Dynamics at Micro‐ and Macroscales
Authors: Dvoyashkin Muslim , Leistenschneider Desirée , Evans Jack D. , Sander Miriam , Borchardt Lars
Published: May 2021

The rate of charging of supercapacitors depends on how quickly ions can reach and accommodate the surface of electrodes. Diffusivity, a parameter reflecting the speed of ions’ migration, is believed to be crucial in designing supercapacitor electrodes. Herein, this belief is questioned, shedding light on a puzzling and potentially critical feature of ionic dynamics denoted as confinement‐induced ion–solvent separation. This effect can lead to a strong slowdown of the ion mobility inside hierarchical pore networks. Explanations for when such an effect occurs and how it can be circumvented are provided. Furthermore, this microscopic picture of diffusion seen by NMR is bridged with the macroscopic charging behavior of supercapacitors investigated by impedance spectroscopy. Quantifying the average residence time of ions within carbon particles shows that the nanopore environment may not be the rate‐limiting factor for the overall ion mobility and thus performance of a cell—as commonly expected. Combining direct diffusion studies performed with neat and solvated ionic liquids and those on organic electrolytes, the so far lacking criteria for the rational selection of electrolyte–carbon systems is developed and recommendations for the preparation of transport‐optimized materials for supercapacitors to minimize ionic diffusion limitations are given.
Galvanic Couples in Ionic Liquid‐Based Electrolyte Systems for Lithium Metal Batteries—An Overlooked Cause of Galvanic Corrosion?
Authors: Dohmann Jan Frederik , Horsthemke Fabian , Küpers Verena , Bloch Sophia , Preibisch Yves , Kolesnikov Aleksei , Kolek Martin , Stan Marian Cristian , Winter Martin , Bieker Peter
Published: May 2021

The breakthroughs in rechargeable lithium metal‐anode‐based batteries is still challenged by safety and performance limitations. Ionic liquid (IL)‐based electrolytes are in consideration for increased safety but their moderate electrolyte performance and high costs still suppress their usefulness in Li metal‐batteries. In an effort to deepen the understanding of the limited performance, galvanic corrosion as an electrochemical degradation process is herein identified as a contributing factor toward battery cell deterioration. Four different ILs, based on bis(trifluoromethylsulfonyl)imide in combination with the quaternary ammonium cations N‐butyl‐N‐methylpyrrolidinium, N‐methyl‐N‐propyl‐pyrrolidinium, N‐butyl‐N‐methylpiperidinium, and N‐butyltrimethylammonium, respectively, are systematically investigated for such corrosive side reactions. The reaction pathways of this commonly neglected phenomenon are found to be both Hofmann‐type and reductive eliminations. Supported by headspace‐gas chromatography‐mass spectrometry, the evolving gaseous reaction products are characterized. With zero resistance ammetry and Li electrochemical dissolution and deposition experiments, the dependency of galvanic corrosion on the presence of the galvanically coupled materials is elucidated. Variation of the lithium bis(trifluoromethylsulfonyl)imide concentration in the electrolytes is shown to influence the extent of detectable degradation products. Based on these findings, the necessity for more sophisticated electrode designs and electrolyte formulations is emphasized.
Website usability analysis of United States emergency medicine residencies
Authors: Fundingsland Edwin , Fike Joseph , Calvano Joshua , Raja Ali , Lai Deborah , Silacci Sara , Haas Mary , Chan Teresa , He Shuhan
Published: May 2021

Objectives

The Council of Residency Directors (CORD) in Emergency Medicine (EM) has recommended that all residency programs should conduct virtual interviews for the 2020 to 2021 application cycle due to the COVID‐19 pandemic. While factors such as geographical region, city, program size, or hospital affiliation are not modifiable, EM residencies can bridge the information gap created by a lack of face‐to‐face interaction by representing themselves digitally. Measuring usability provides an objective method for EM residencies to improve their Web presence and effectively represent themselves to applicants.

Methods

Our sample set included 55 U.S. EM residency program websites. Using methodology replicated from previous literature on health care website usability, we divided usability into four categories for quantifiable analysis: accessibility, marketing, content quality, and technology. Analysis was performed on each website and scored in all four categories. A “general usability” score was calculated for each website using a composite of the key factors within the four categories. Using a weighted percentage across all of the factors, an overall score was calculated.

Results

Content quality was the overall highest scoring category (mean ± SD = 5.4, SE = 0.33). The overall lowest performing category was technology (mean ± SD = 0.8 ± 0.09, SE = 0.01).

Conclusions

Measuring usability can help EM residency programs identify ways to improve their Web presence. To effectively promote their programs, residencies need quality content that communicates their key features. Our recommendation is for all residency programs to periodically perform website audits and apply the usability measures outlined to improve their digital presence, especially during times when face‐to‐face interactions will be limited.
Sensitivity of reference evapotranspiration to weather variables across seven regions of Turkey
Authors: Yildirim Tugba , Wagle Pradeep , Gowda Prasanna H. , Mengu Gulay P.
Published: May 2021

Daily weather data from 1984 to 2018 for 14 weather stations representing seven regions of Turkey were used to estimate reference evapotranspiration (ETref). We performed sensitivity analyses of input weather variables (air temperature, wind speed, and solar radiation) to determine the relative effects of measurement errors in weather data on the accuracy of calculated grass (ETos) and alfalfa (Medicago sativa L., ETrs) reference ET. In addition, changes in estimated irrigation water requirement for maize (Zea mays L.), a major crop in all regions of Turkey, due to errors in major climatic variables were also determined across seven regions of Turkey. Comparison of the sensitivity coefficients indicated that ETref was most sensitive to wind speed (sensitivities from −2.46 to 5.56 mm d–1), followed by air temperature (sensitivities from −2.13 to 3.1 mm d–1) across Turkey. However, responses of ETos and ETrs to changes in weather variables varied across the regions. For examples, the Marmara region had the largest impact of errors in air temperature but the smallest impact of errors in wind speed on the calculated ETref. Likewise, the Southeastern and Eastern Anatolia regions had the greatest impact of errors in wind speed but the smallest impact of errors in air temperature on the calculated ETref. The errors in weather variables led to substantial over‐ or underestimation of irrigation water requirement for maize. In some cases, irrigation water requirement was overestimated by more than double. These results suggest that different sensor accuracies are needed for weather stations in different regions of Turkey to accurately estimate ETref and irrigation water requirement.
Chemical immobilization of amino acids into robust metal–organic framework for efficient SO2 removal
Authors: Zhu Zhenliang , Zhang Peixin , Li Bei , Chen Shixia , Deng Qiang , Zeng Zheling , Wang Jun , Deng Shuguang
Published: May 2021

Adsorptive removal of trace SO2 emissions from flue‐gases can significantly reduce energy and water consumption and minimize the amount of unmanageable waste, however, this remains a great challenge. Herein, we report a universal strategy of chemical immobilization of amino acids into a robust metal–organic framework to enhance deep desulfurization. The grafted amino acid resulted in the formation of pores with compatible pore sizes and created abundant N‐containing moieties for selective SO2 adsorption. MOF‐808‐His (His = l‐histidine) exhibited a top‐ranking SO2 uptake (10.4 mmol g−1) with an excellent SO2/CO2 selectivity (90.5) under ambient conditions; furthermore, MOF‐808‐His could be easily regenerated. Breakthrough curves verified its excellent separation performances with water vapor and real flue‐gas compositions. Computational simulations confirmed the vital role of immobilized amino acids in improving the SO2 capture ability and selectivity. As a proof‐of‐concept, five natural amino acids were immobilized into MOF‐808; all samples displayed improved adsorptive desulfurization performances.
Mathematical approach to compute the molecular composition of hydrothermal liquefaction‐derived renewable crude oil
Authors: Saxena Nikhlesh , Prabhu Vishwas , Chandra Himanshu , Ghadge Rajaram , Bhujade Ramesh , Sapre Ajit
Published: May 2021

Hydrothermal liquefaction (HTL), a thermo‐chemical conversion process, uses water as a reaction medium at elevated pressure and temperature, to convert biomass to renewable liquid fuel and recovers fertilizer‐rich water. To assess the techno‐economic screening of HTL oils from various feedstock, it is crucial to have information on molecular composition of the feed and products. There are limitations of existing analytical methods to identify and quantify all the molecules present in the bio‐fuel. Therefore, there is a need to find alternate ways to quantify the molecular composition of feed and expected products. The modeling work on bio‐oil is developed and validated on mathematical approach using simple analytical results like CHNO along with structural analysis of oil like Fourier‐transform infrared, nuclear magnetic resonance analysis for HTL derived oil from microalgae. This mathematical framework is further extended to predict the molecular composition of oil obtained from HTL of feedstocks like mixed plastic waste, sludge, and so on. A multi‐dimensional molecular matrix is developed based on the distributions of side chains, aromatic rings, and olefinic carbon on top of core molecules. The parameters of the distributions are estimated computationally using global optimization algorithm (genetic algorithm) and local optimization algorithm to predict a mixture composition that matches closely with bulk properties of the product.
Interactive Human–Robot Skill Transfer: A Review of Learning Methods and User Experience
Authors: Cansev Mehmet Ege , Xue Honghu , Rottmann Nils , Bliek Adna , Miller Luke E. , Rueckert Elmar , Beckerle Philipp
Published: May 2021

Generalizing the operation of robots in dynamical environments regardless of the task complexity is one of the ultimate goals of robotics researchers. Learning from demonstration approaches supported by transfer learning and user feedback offer a remarkable solution to achieve generalization. The main idea behind such approaches is teaching robots new skills with human instructors and training parametric models with data from demonstrations to achieve and update the desired skills under changing conditions. Herein, the applications of skill transfer with reinforcement learning algorithms and the effect of user experience (UX) on learning from demonstration approaches are reviewed. This review outlines the importance of considering and evaluating UX during human–robot interaction and, especially, robot teaching. A detailed view on the relations between robot learning and UX is provided and approaches for future improvements are derived. Finally, adaptive autonomy sharing between the robot and the user during teaching is presented as a promising approach to enhance the interaction by exploiting user feedback. In the long run, interactive and user‐centered human–robot skill transfer is expected to reduce cognitive and physical load of the user. Discussion on future research questions aiming to improve learning process and semiautonomous behavior concludes the review.
Programmable Amplitude‐Coding Metasurface with Multifrequency Modulations
Authors: Hong Qiao Ru , Ma Qian , Gao Xin Xin , Liu Che , Xiao Qiang , Iqbal Shahid , Cui Tie Jun
Published: May 2021

Recently, programmable metasurfaces have aroused great attention for various applications such as beam manipulation, wireless communication, and holograms by modulating the spatial phase or amplitude. However, programmable amplitude‐coding modulations have rarely been investigated due to the difficulty in realizing dynamic control of amplitude. Herein, a real‐time programmable amplitude‐coding metasurface with multifrequency modulation is proposed by integrating PIN diodes and chip attenuators to the metaelement. The element is encoded as “11,” “10,” and “00,” corresponding to the ON/OFF states of two diodes. By switching the two states of the PIN diode, the metaelement exhibits distinctly reflected amplitude responses in three frequencies (2.98, 4.11, and 5.73 GHz). For the whole metasurface, the magnitude of the reflected beam can be modulated with some specific coding patterns. To verify the performance, six coding patterns with 10 × 10 metaelements are designed, and four of them are measured. Experimental results are fundamentally consistent with theoretical designs and simulations. Further a wireless communication demonstration is designed and implemented to perform direct modulation of digital signals without using mixers required in the conventional wireless communication systems. It is envisioned that this work will find applications in new architecture encrypted communication and imaging systems.
Engineering Magnetic Micro/Nanorobots for Versatile Biomedical Applications
Authors: Wang Longchen , Meng Zheying , Chen Yu , Zheng Yuanyi
Published: May 2021

With the rapid development of micro/nanomanufacturing technology, a variety of multifunctional micro/nanorobots have emerged. In particular, magnetic actuation‐based micro/nanorobots have attracted much interest due to their advantages of untethered contact, remote control, noninvasiveness, and high tissue‐penetrating capability. Various magnetic micro/nanorobots have been designed and applied in biomedicine, which indicates the great potential of clinical transformation. This article reviews the new advancements of engineering magnetic micro/nanorobots for versatile biomedical applications, ranging from targeted delivery, minimally invasive surgery, cellular and intracellular measurement, and intelligent sensing to detoxification and antibacterial applications. The controllability, visualization, and biosafety aspects of magnetically manipulated micro/nanorobots are summarized. In particular, the challenges being faced are discussed to outlook future prospective development.
Facile Manufacturing Route for Magneto‐Responsive Soft Actuators
Authors: Carpenter Julia A. , Eberle Thomas B. , Schuerle Simone , Rafsanjani Ahmad , Studart André R.
Published: May 2021

Magnetically driven soft actuators are unique because they are fast, remote‐controlled, conformal to rigid objects, and safe to interact with humans. Despite these multiple functionalities, a broader utilization of such actuators is hindered by the high cost and equipment‐intensive nature of currently available manufacturing processes. Herein, a simple fabrication route for magneto‐responsive soft actuators is described using cost‐effective and broadly available raw materials and equipment. The method utilizes castable silicone resins that are loaded with magnetic particles and subsequently magnetized under an external magnetic field. The experimental investigation of silicone‐based composites prepared with particles of distinct chemistries, sizes, and morphologies enables the identification of the raw materials and magnetization conditions required for the process. This leads to functional soft actuators with programmable magnetic patterns that are capable of performing pick‐and‐place, lifting, catching, and moving tasks under the remote action of an external magnetic field. By removing manufacturing hurdles associated with costly raw materials and equipment, the proposed approach is expected to facilitate the design, implementation, and exploitation of the unique functionalities of magneto‐controlled soft actuators in a wider number of applications.
The Roles of Settings in Supporting Immigrants’ Resistance to Injustice and Oppression: A Policy Position Statement by the Society for Community Research and Action
Authors: Buckingham Sara L. , Langhout Regina Day , Rusch Dana , Mehta Tara , Rubén Chávez Noé , Ferreira van Leer Kevin , Oberoi Ashmeet , Indart Monica , Paloma Virginia , King V. Elizabeth , Olson Bradley
Published: May 2021

In 2018, in response to increasingly oppressive and widespread federal immigration enforcement actions in the United States (U.S.) and around the globe – including family separation, immigration raids, detention, deportation of people who have lived in the country for much of their lives – the Society for Community Research & Action produced a statement on the effects of deportation and forced separation on immigrants, their families, and communities (SCRA, 2018). The statement focused exclusively on the impacts of deportation and forced family separation, documenting the damage done by oppressive U.S. policies and practices. We felt it was imperative to document this harm, and yet were uncomfortable producing a narrow paper that focused solely on harm. There are multiple ways immigrants and their allies resist deportation and other forms of oppression. This resistance is done individually, collectively, and in settings that vary in size and scope, including community‐based, faith‐based, direct care, and educational settings, as well as entire municipalities and transnational organizing settings. Settings facilitate resistance in many ways, focusing on those who are oppressed, their oppressors, and systems of oppression. In this statement, we describe the unique and overlapping ways in which settings facilitate resistance. We situate this review of the scientific and practice literature in the frameworks of change through social settings, empowering settings, healing justice, and decolonization. We also document recommendations for continued resistance.
A new syndrome of moyamoya disease, kidney dysplasia, aminotransferase elevation, and skin disease associated with de novo variants in RNF213
Authors: Strong Alanna , O'Grady Gina , Shih Evelyn , Bishop Jonathan R. , Loomes Kathleen , Diamond Tamir , Hartung Erum A. , Wong William , Cuddapah Sanmati , Cahill Anne Marie , Hou Cuiping , Slater Diana , Vaccaro Courtney , Watson Deborah , Li Dong , Hakonarson Hakon
Published: May 2021

Ring‐finger protein 213 (RNF213) encodes a protein of unknown function believed to play a role in cellular metabolism and angiogenesis. Gene variants are associated with susceptibility to moyamoya disease. Here, we describe two children with moyamoya disease who also demonstrated kidney disease, elevated aminotransferases, and recurrent skin lesions found by exome sequencing to have de novo missense variants in RNF213. These cases highlight the ability of RNF213 to cause Mendelian moyamoya disease in addition to acting as a genetic susceptibility locus. The cases also suggest a new, multi‐organ RNF213‐spectrum disease characterized by liver, skin, and kidney pathology in addition to severe moyamoya disease caused by heterozygous, de novo C‐terminal RNF213 missense variants.
Microdeletion of 9q22.3: A patient with minimal deletion size associated with a severe phenotype
Authors: Ewing Adam D. , Cheetham Seth W. , McGill James J. , Sharkey Michael , Walker Rick , West Jennifer A. , West Malcolm J. , Summers Kim M.
Published: May 2021

Basal cell nevus syndrome (also known as Gorlin Syndrome; MIM109400) is an autosomal dominant disorder characterized by recurrent pathological features such as basal cell carcinomas and odontogenic keratocysts as well as skeletal abnormalities. Most affected individuals have point mutations or small insertions or deletions within the PTCH1 gene on human chromosome 9, but there are some cases with more extensive deletion of the region, usually including the neighboring FANCC and/or ERCC6L2 genes. We report a 16‐year‐old patient with a deletion of approximately 400,000 bases which removes only PTCH1 and some non‐coding RNA genes but leaves FANCC and ERCC6L2 intact. In spite of the small amount of DNA for which he is haploid, his phenotype is more extreme than many individuals with longer deletions in the region. This includes early presentation with a large number of basal cell nevi and other skin lesions, multiple jaw keratocysts, and macrosomia. We found that the deletion was in the paternal chromosome, in common with other macrosomia cases. Using public databases, we have examined possible interactions between sequences within and outside the deletion and speculate that a regulatory relationship exists with flanking genes, which is unbalanced by the deletion, resulting in abnormal activation or repression of the target genes and hence the severity of the phenotype.
Death rates in the U.S. due to Leukodystrophies with pediatric forms
Authors: Barczykowski Amy L. , Langan Thomas J. , Vanderver Adeline , Jalal Kabir , Carter Randy L.
Published: May 2021

To use national mortality and state death certificate records to estimate disease specific mortality rates among pediatric and adult populations for 23 leukodystrophies (LDs) with pediatric forms. Additionally, to calculate yearly prevalence and caseload of the most severe LD cases that will eventually result in pediatric death (i.e., pediatric fatality cases). Death certificate records describing cause of death were collected from states based on 10 ICD‐10 codes associated with the 23 LDs. Deaths in the U.S. with these codes were distributed into categories based on proportions identified in state death certificate data. Mortality rates, prevalence, and caseload were calculated from resulting expected numbers, population sizes, and average lifetimes. An estimated 1.513 per 1,000,000 0–17 year old's died of these LDs at average age 5.2 years and 0.194 for those ≥18 at an average age of 42.3 years. Prevalence of pediatric fatality cases of these LDs declined from 1999 through 2007 and then remained constant at 6.2 per million children per year through 2012. Epidemiological information, currently lacking for rare diseases, is useful to newborn screening programs, research funding agencies, and care centers for LD patients. Methods used here are generally useful for studying rare diseases.
Biomedical Applications of Metal–Organic Frameworks at the Subcellular Level
Authors: Xue Jueyi , Liu Jian , Yong Joel , Liang Kang
Published: May 2021

Organelles, or subcellular structures, are the fundamental functional units in almost all eukaryotic cells. Consequently, they play a critical role in the development of various biomedical applications, such as targeted drug delivery, biosensing, imaging, and biomimetics. Many efforts are devoted to developing nanosystems that can target specific organelles in a controlled manner. A series of nanomaterials with high porosity, stability, and easy‐to‐tailor properties, named metal–organic frameworks (MOFs), have shown to be a promising new class of nanocarriers and bioprotective exoskeletons for biomedical and biocatalytical platforms at the subcellular level. Herein, the recent state‐of‐the‐art progress of MOF nanomaterials for bioapplications at the subcellular level is highlighted. In the first section, MOF‐derived biomimetics organelles and subcellular structures are highlighted. Then, the strategies of organelle‐targeted MOF therapy and biosensing are illustrated. Next, MOF‐based biopreservation of organelles is introduced. Finally, a personal perspective about the challenges and future innovative designs is discussed.
Bamboo‐like π‐Nanotubes with Tunable Helicity and Circularly Polarized Luminescence
Authors: Wang Yuan , Wan Kaiwei , Pan Fei , Zhu Xuefeng , Jiang Yuqian , Wang Hui , Chen Yuli , Shi Xinghua , Liu Minghua
Published: May 2021

We report the fabrication of an exotic bamboo‐like π‐nanotube via the hierarchical self‐assembly of a dipeptide‐substituted naphthalenediimide gelator with tunable helicity and circularly polarized luminescence (CPL). It was found that in the presence of trifluoroacetic acid (TFA) the gelator molecules self‐assembled into a bamboo‐like π‐nanotube, which is composed of truncated nanocones and CPL active. When defining the diameter ratio of the lower to upper edge of each nanocone as a parameter to express the helicity of different nanotubes, it was found that both the helicity and CPL of these nanotubes can be adjusted by the amount of TFA. Moreover, the helicity of the nanotube can be conveyed to the achiral quantum dots (QDs) and produce a hybrid nanotube/QDs CPL active materials with adjustable dissymmetry factor. This work finds a new type self‐assembled bamboo‐like π‐nanotube and unveils their helicity and CPL control.
Reply to a Comment on “The Nature of Chalcogen‐Bonding‐Type Tellurium–Nitrogen Interactions”
Authors: Vishnevskiy Yury V. , Mitzel Norbert W.
Published: May 2021

We reply to the comment by J.‐M. Mewes, A. Hansen and S. Grimme (MHG), who challenged the accuracy of our re value for the N⋅⋅⋅Te distance in (C6F5)Te(CH2)3NMe2 determined by gas electron diffraction (GED). We conclusively demonstrate that MHG′s quoted reference calculations are less accurate than they claim for solid state and gas phase. We show by higher level calculations, that we did not miss substantial contributions from open‐chain conformers. Refinements on simulated scattering data show that such contributions would have had only an almost negligible effect on re(N⋅⋅⋅Te). MHG suggested the use of a H0‐tuned GFN method for calculating vibrational corrections ra−re, but this did not change these values substantially. Alternative amplitude calculations using higher level analytic harmonic and numeric cubic force fields (PBE0‐D3BJ/def2‐TZVP) yield a GED value for re(N⋅⋅⋅Te)=2.852(25) Å that is well within the experimental error of our original value 2.918(31) Å but far from the 2.67(8) Å predicted by MHG. A now improved error estimation accounts for inaccuracies in the calculated auxiliary values. The gas/solid difference of the weak N⋅⋅⋅Te interaction is in a realistic range compared to other systems involving weak chemical interactions.
Ultrasonic‐assisted preparation of Co3O4 and Eu‐doped Co3O4 nanocatalysts and their application for solvent‐free synthesis of 2‐amino‐4H‐benzochromenes under microwave irradiation
Authors: Kafi‐Ahmadi Leila , Poursattar Marjani Ahmad , Nozad Ehsan
Published: May 2021

Co3O4 and Eu‐doped Co3O4 nanocatalysts were synthesized through an ultrasonic‐assisted solvothermal method and were characterized with X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR), energy‐dispersive X‐ray (EDX), and field‐emission scanning electron microscopy (FESEM) methods. Spinel cubic crystalline system for synthesized nanocatalysts was confirmed with XRD, whereas the spherical morphology of Co3O4 changed to nanorods after Eu3+ doping, which was affirmed with FESEM micrographs. Catalytic performance of the nanomaterials was examined through the synthesis of 2‐amino‐4H‐benzochromenes using aromatic aldehydes, malononitrile, and β‐naphthol condensation under solvent‐free conditions and microwave irradiation. Mild reaction conditions, short reaction times, simple setup, using an affordable catalyst, and high‐quality products were some of the advantages of this procedure. The efficiency for Eu‐doped nanocatalyst was achieved by about 96%.
Co (II) and Cd (II) complexes with imidazole‐2‐carboxaldehyde groups: spectroscopic, antibacterial, Hirshfeld surfaces analyses, and TD/DFT calculations
Authors: Xu Li‐Yan , Chai Yong‐Mei , Li Cheng‐Guo , Chai Lan‐Qin
Published: May 2021

Two complexes [Co(L)2·2CH3OH]2·(NO3)4 (1) and [Cd(L)2(NO3)2] (2) (L = 2‐(2‐imidazolyl)‐4‐methyl‐1,2‐dihydroquinazoline‐3‐oxide) were synthesized by natural evaporation of Co (II)/Cd (II) nitrate with a new heterocyclic ligand. The metal complexes are characterized by elemental analysis, spectroscopy, and X‐ray crystallographic. In the crystal structures, Co (II) complex 1 was in a six‐coordinated coordination environment and constituted an infinite 1‐D chain, 2‐D network, Meter‐shaped 3‐D supramolecular framework, while Cd (II) complex 2 assembled into an infinite 1‐D, wave‐like 2‐D, and dragonfly‐shaped 3‐D skeleton. Specifically, nitrate ions were present as a dissociated group in complex 1, whereas complex 2 was involved in the coordination. Moreover, Cd (II) complex exhibited different fluorescence behaviors in diverse solvents. Remarkably, all the compounds have shown perceptible antibacterial activity against Gram‐positive and Gram‐negative bacteria. Furthermore, the electrostatic potential (ESP) calculations were utilized to analyze electrophilic and nucleophilic attack sites on the molecule, which verified the existence of hydrogen bonds in the optimized crystal structure. In addition, the structural features of metal complexes have been remarkably rationalized, and the overall trends obtained in the experimental values have been resoundingly remade by TD/DFT calculations. The detailed Hirshfeld surface analysis and fingerprint plots yielded a comparative picture of the mode of non‐covalent interactions.
Local government performance and democratic consolidation: Explaining ordinance proposal in Busan Metropolitan Council
Authors: Lee Byung‐Jae , Kim Tae Wan , Suh Jaekwon , Yap O. Fiona
Published: May 2021

This article assesses the role of local councils as a conduit for democratic consolidation through the examination of the legislative performance of the members of a South Korean metropolitan city council. We collected data on ordinance proposals in Busan Metropolitan Council from 2006 to 2018 (the 5th to 7th Councils) and analysed, first, the effects of individual attributes of local council members on legislative performance through negative binomial model analysis and, second, the effects of legislative networks on council members' performance. Three findings contribute to the literature: first, the number of proposed ordinances by council members increased over time, while those by the mayor decreased in the same period, suggesting an erosion of executive dominance of policymaking in local councils. Second, female and newly elected council members are most active in legislative proposals, which underlines that these members are more connected to the electorate than long‐serving incumbents. Third, network analyses show increasingly diverse and multi‐centred communities behind ordinance proposals; this suggests a move from personalistic politics to institutionalised politics.