bluuebunny/crossref_metadata_2025 huggingface dataset:
Inkjet Printing Controllable Polydopamine Nanoparticle Line Array for Transparent and Flexible Touch‐Sensing Application
Authors: Liu Liang , Pei Yunheng , Ma Siyuan , Sun Xiaoze , Singler Timothy J.
Published: January 2020

A cost‐effective and environmentally benign inkjet‐printing technique is reported for fabrication of ultra‐fine polydopamine (PDA) nanoparticle line arrays (NPLAs) with controllable line‐to‐line spacing (pitch size). The narrowest single line width achieved is 4.7 μm, and tunable pitch size ranging from 77 to 380 μm is also achieved by exploitation of the evaporation‐driven convective particle self‐assembly mechanism. Controllable pitch size is accomplished by printing on hydrophobically recovered polyethylene terephthalate (PET) substrates after oxygen plasma treatment. A theoretical model is developed to investigate the NPLA growth mechanism, which shows good agreement with experimental measurements. Conversion of the NPLA to electrically conductive structure is achieved by a subsequent silver electroless metallization process. The fabrication of a transparent capacitive touch sensor as an application of this approach is also demonstrated. This technique offers manufacturing of conductive narrow lines by additive means with the advantages of low cost, low process temperature, and minimal environmental impact.
Blue‐Emitting Iridium(III) Complexes for Light‐Emitting Electrochemical Cells: Advances, Challenges, and Future Prospects
Authors: Bai Rubing , Meng Xianwen , Wang Xiaoxiang , He Lei
Published: January 2020

Light‐emitting electrochemical cells (LECs) are one of the most promising technologies for solid‐sate lighting. Among them, LECs based on phosphorescent iridium(III) complexes have attracted significant research interest in the past 15 years, because of their high efficiency and tunable emission color across the entire visible spectrum. To fabricate white LECs for lighting, high‐performance blue LECs are the first prerequisite. Huge efforts have been devoted to improving the performances of blue LECs based on iridium(III) complexes either by developing new blue‐emitting complexes or by engineering the devices. Nevertheless, blue LECs have still shown much lower performances (brightness, efficiency, stability, etc.) compared to the red, orange‐red, yellow, and green counterpart devices. In particular, a single blue LEC with satisfactory blue‐color purity, high efficiency, and high stability is still missing. Here, the advances in blue‐emitting iridium(III) complexes for LECs and the device engineering on LECs using the complexes are reported. The challenges ahead are discussed, and future prospects are outlined.
Toward Artificial Cells: Novel Advances in Energy Conversion and Cellular Motility
Authors: Jeong Sungwoo , Nguyen Huong Thanh , Kim Chang Ho , Ly Mai Nguyet , Shin Kwanwoo
Published: January 2020

The demand to discover every single cellular component has been continuously increasing along with the development of biological techniques. The bottom‐up approach to construct a cell‐mimicking system from well‐defined and tunable compositions is accelerating, with the ultimate goal of comprehending a biological cell. From among the available techniques, the artificial cell has been increasingly recognized as one of the most powerful tools for building a cell‐like system from scratch. This review summarizes the development of artificial cells, from a pure giant unilamellar vesicle (GUV) to a controllable, self‐fueled proteoliposome, both of which are highly compartmentalized. The basic components of an artificial cell, as well as the optimal conditions required for successful, reproducible GUV formation and protein reconstitution, are discussed. Most importantly, progress in studying the metabolic reactions in and the motility of a reconstituted artificial cell are the main focus of the review. The ability to perform a complicated reaction cascade in a controllable manner is highlighted as a promising perspective to obtaining an autonomous and movable GUV.
Mechanically Programmable Dip Molding of High Aspect Ratio Soft Actuator Arrays
Authors: Becker Kaitlyn P. , Chen Yufeng , Wood Robert J.
Published: January 2020

This work presents multiple methods of creating high aspect ratio fluidic soft actuators that can be formed individually or in large arrays via dip coating. Within this methodology, four strategies are provided to mechanically program the motion of these actuators, including the use of fiber inclusions, gravity, surface tension, and electric fields. The modular nature of this dip coating fabrication technique is inexpensive, easy to modify, and scalable. These techniques are used to demonstrate the fabrication of soft actuators with aspect ratios up to 200:1 and integrated arrays of up to 256 actuators. Furthermore, these methods have the potential to achieve higher aspect ratios and larger array sizes. Operating pressure, curvature, and curling strength tests reveal the design space in which fabrication parameters can be selected to tune the input and output parameters of soft bending actuators. An individual bending actuator made with these methods weighs between 0.15 and 0.5 g, can hold up to 2 N, and can be designed to work in groups to increase curling strength with distributed contact forces. Arrays of these actuators may be useful in atypical grasping and manipulation tasks, fluid manipulation, and locomotion.
A Universal Lab‐on‐Salt‐Particle Approach to 2D Single‐Layer Ordered Mesoporous Materials
Authors: Liu Liangliang , Yang Xuanyu , Xie Yujie , Liu Huan , Zhou Xinran , Xiao Xingyu , Ren Yuan , Ma Zhen , Cheng Xiaowei , Deng Yonghui , Zhao Dongyuan
Published: January 2020

The advantages of existing ordered mesoporous materials have not yet been fully realized, due to their limited accessibility of in‐pore surface and long mass‐diffusion length. A general, controllable, and scalable synthesis of a family of two‐dimensional (2D) single‐layer ordered mesoporous materials (SOMMs) with completely exposed mesopore channels, significantly improved mass diffusion, and diverse framework composition is reported here. The SOMMs are synthesized via a surface‐limited cooperative assembly (SLCA) on water‐removable substrates of inorganic salts (e.g., NaCl), combined with vacuum filtration. As a proof of concept, the obtained CeO2‐based SOMMs show superior catalytic performance in CO oxidation with high conversion efficiency, ≈33 times higher than that of conventional bulk mesoporous CeO2. This SLCA is a promising approach for developing next‐generation porous materials for various applications.
Variable‐Temperature Electron Transport and Dipole Polarization Turning Flexible Multifunctional Microsensor beyond Electrical and Optical Energy
Authors: Cao Mao‐Sheng , Wang Xi‐Xi , Zhang Min , Cao Wen‐Qiang , Fang Xiao‐Yong , Yuan Jie
Published: January 2020

Humans are undergoing a fateful transformation focusing on artificial intelligence, quantum information technology, virtual reality, etc., which is inseparable from intelligent nano–micro devices. However, the booming of “Big Data” brings about an even greater challenge by growing electromagnetic radiation. Herein, an innovative flexible multifunctional microsensor is proposed, opening up a new horizon for intelligent devices. It integrates “non‐crosstalk” multiple perception and green electromagnetic interference shielding only in one pixel, with satisfactory sensitivity and fast information feedback. Importantly, beneficial by deep insight into the variable‐temperature electromagnetic response, the microsensor tactfully transforms the urgent threat of electromagnetic radiation into “wealth,” further integrating self‐power. This result will refresh researchers' realization of next‐generation devices, ushering in a new direction for aerospace engineering, remote sensing, communications, medical treatment, biomimetic robot, prosthetics, etc.
Engineering Oxygen Vacancies in a Polysulfide‐Blocking Layer with Enhanced Catalytic Ability
Authors: Li Zhaohuai , Zhou Cheng , Hua Junhui , Hong Xufeng , Sun Congli , Li Hai‐Wen , Xu Xu , Mai Liqiang
Published: January 2020

The practical application of the lithium–sulfur (Li–S) battery is seriously restricted by its shuttle effect, low conductivity, and low sulfur loading. Herein, first‐principles calculations are conducted to verify that the introduction of oxygen vacancies in TiO2 not only enhances polysulfide adsorption but also greatly improves the catalytic ability and both the ion and electron conductivities. A commercial polypropylene (PP) separator decorated with TiO2 nanosheets with oxygen vacancies (OVs‐TiO2@PP) is fabricated as a strong polysulfide barrier for the Li–S battery. The thickness of the OVs‐TiO2 modification layer is only 500 nm with a low areal mass of around 0.12 mg cm−2, which enhances the fast lithium‐ion penetration and the high energy density of the whole cell. As a result, the cell with the OVs‐TiO2@PP separator exhibits a stable electrochemical behavior at 2.0 C over 500 cycles, even under a high sulfur loading of 7.1 mg cm−2, and an areal capacity of 5.83 mAh cm−2 remains after 100 cycles. The proposed strategy of engineering oxygen vacancies is expected to have wide applications in Li–S batteries.
Shine Bright Like a Diamond: New Light on an Old Polymeric Semiconductor
Authors: Giusto Paolo , Cruz Daniel , Heil Tobias , Arazoe Hiroki , Lova Paola , Aida Takuzo , Comoretto Davide , Patrini Maddalena , Antonietti Markus
Published: January 2020

Brilliance usually refers to the light reflected by the facets of a gemstone such as diamond due to its high refractive index. Nowadays, high‐refractive‐index materials find application in many optical and photonic devices and are mostly of inorganic nature. However, these materials are usually obtained by toxic or expensive production processes. Herein, the synthesis of a thin‐film organic semiconductor, namely, polymeric carbon nitride, by thermal chemical vapor deposition is presented. Among polymers, this organic material combines the highest intrinsic refractive index reported so far with high transparency in the visible spectrum, even reaching the range of diamond. Eventually, the herein presented deposition of high quality thin films and their optical characteristics open the way for numerous new applications and devices in optics, photonics, and beyond based on organic materials.
A Removable Insertion Shuttle for Ultraflexible Neural Probe Implantation with Stable Chronic Brain Electrophysiological Recording
Authors: Zhang Shun , Wang Chengjun , Gao Huan , Yu Chaonan , Yan Qinghao , Lu Yuchen , Tao Zhehao , Linghu Changhong , Chen Zhou , Xu Kedi , Song Jizhou
Published: January 2020

Ultraflexible neural probe is an ideal tool for brain research, which can reduce the mechanical interfacial mismatch between electrodes and brain tissue and can thus reduce the tissue's inflammation and extend the electrodes' service life. However, the low stiffness of ultraflexible neural probe makes it susceptible to bending and buckling during insertion into brain. Here, a simple yet robust design of removable insertion shuttle consisting of a steel needle with a dissolvable spheroid micropost is reported for ultraflexible neural probe implantation. The dissolvable spheroid micropost of insertion shuttle is fabricated by the simple dip‐coating process based on the competition and balance between the surface tension and gravity. A temporary engaging mechanism enabled by the micropost engaged into the via hole on the tip of ultraflexible neural probe is adopted to enable an easy and quick implantation. Experimental studies reveal the fundamental aspects of the design of removable insertion shuttle and the operation of implantation. In vivo implantation of ultraflexible neural probes into rat's brain illustrates the unusual capabilities of removable insertion shuttle with the accurate positioning of probe at desired depth and the stable chronic brain electrophysiological recording, which show great potential in both basic neuroscience and clinical applications.
Flexible Difunctional (Pressure and Light) Sensors Based on ZnO Nanowires/Graphene Heterostructures
Authors: Wang Yuan , Zhu Laipan , Du Cuifeng
Published: January 2020

The piezotronic and piezo‐phototronic effects have been extensively utilized in the third‐generation semiconductors, such as ZnO, CdS, and GaN, to enhance the performances of electronic and optoelectronic devices. Using the principle of these two effects, here, a flexible difunctional sensor based on graphene/ZnO nanowire array, which can be used to detect vertical pressure as well as ultraviolet light power, is presented. This device shows a linear response to vertical pressures by measuring the change of current, and a pressure sensitivity of 1.7 nA kPa−1 for smaller pressures. It can also be used to measure the bending strain applied on the substrate. A uniform photoresponsivity of 3.5 µA W−1 for a 325 nm laser excitation is obtained, and the response speeds for light on‐ and off‐states are 28 and 25 ms, respectively, revealing excellent photoelectric property of this device. These nanowires/graphene heterostructures are flexible with low cost and easy fabrication processes, making it potential in applications of wearable electronic and optoelectronic devices.
Ultrathin Scattering Spin Filter and Magnetic Tunnel Junction Implemented by Ferromagnetic 2D van der Waals Material
Authors: Lin Zheng‐Zhe , Chen Xi
Published: January 2020

Emerging research in 2D materials has promoted the development of nanoelectronics. Ferromagnetic van der Waals (vdW) layered materials can be utilized to implement ultrathin spintronic devices with new functionalities. The theoretical investigation of 2D vdW scattering spin filters and magnetic tunnel junctions consisting of atomically thin Fe3GeTe2 (FGT) are reported. By the nonequilibrium Green's function technique, the spin polarization of ballistic transport through single‐/double‐layer FGT sandwiched between two Cu electrodes is predicted to be 53/85%. In ultrathin FGT‐hBN‐FGT heterostructures, remarkable magnetoresistance is observed, in which maximum (minimum) resistance occurs when the magnetization of two FGT layers is parallel (antiparallel) to each other. For heterostructures consisting of single‐/double‐layer FGT, the magnetoresistance reaches 183/252% at zero‐bias limit. The parallel state of a FGT magnetic tunnel junction exhibits spin polarization larger than 75%. These results suggest the application of magnetic vdW layered materials in ultrathin spintronics.
Piezoelectric Response of Polycrystalline Silicon‐Doped Hafnium Oxide Thin Films Determined by Rapid Temperature Cycles
Authors: Mart Clemens , Kämpfe Thomas , Hoffmann Raik , Eßlinger Sophia , Kirbach Sven , Kühnel Kati , Czernohorsky Malte , Eng Lukas M. , Weinreich Wenke
Published: January 2020

The in‐plane piezoelectric response of 20 nm thick Si‐doped HfO2 is examined by exploiting thermal expansion of the substrate upon rapid temperature cycling. The sample is heated locally by a deposited metal film, and the subsequently registered pyroelectric current is found to be frequency dependent in the observed range of 5 Hz to 35 kHz. While the intrinsic response remains constant, the secondary contribution can be switched off in the high‐frequency limit due to substrate clamping. As this secondary response is generated by thermal expansion and the piezoelectric effect, this allows for extraction of the corresponding in‐plane response. By comparing pyroelectric measurements in low‐ and high‐frequency limits, a piezoelectric coefficient d31 of −11.5 pm V −1 is obtained, which is more than five times larger than that of AlN. The magnitude of piezoelectric response increases upon electric field cycling, which is associated with a transition from antiferroelectric‐like behavior to a purely ferroelectric polarization hysteresis. The hafnium oxide material system is proposed as a promising candidate for future CMOS compatible piezoelectric micro‐ and nano‐electromechanical systems (MEMS and NEMS).
Interplay Among Thermoelectric Properties, Atmospheric Stability, and Electronic Structures in Solution‐Deposited Thin Films of P(NaX[Niett])
Authors: Hwang Sunbin , Potscavage William J. , Kim Tae‐Wook , Adachi Chihaya
Published: January 2020

Recent progress in organic thermoelectric generators has resulted in high performance through chemical control of the redox levels of organic semiconductors, but the scarcity of good candidates for soluble organic n‐type materials limits the use of π‐leg structures consisting of complementary elements of p‐ and n‐type materials because of unbalanced transport coefficients that lead to power losses. A sol–gel technique with oxidation is demonstrated to be effective for the fabrication of smooth films of poly(nickel 1,1,2,2‐ethenetetrathiolate), P(MX[Niett]), which is known as an insoluble material. By controlling the annealing temperature, a maximum n‐type power factor of 10.1 μW m−1 K−2 at 100 °C (Seebeck coefficient of −35.4 μV K−1 and electrical conductivity of 80.3 S cm−1) is demonstrated. Chemical and electronic structures of P(MX[Niett]) thin films are explored based on changes in optical absorption, ultraviolet, and X‐ray photoelectron spectroscopies to understand the origin of the high atmospheric stability. Analysis indicates that the stability arises from electronic states of the doped state that satisfy a balance with the redox potential of the air components and that stability under repeated redox reactions is an important factor for obtaining the n‐type organic thermoelectric materials that are highly stable in air.
Critical Role of Polymer Aggregation and Miscibility in Nonfullerene‐Based Organic Photovoltaics
Authors: Yi Xueping , Peng Zhengxing , Xu Bing , Seyitliyev Dovletgeldi , Ho Carr Hoi Yi , Danilov Evgeny O. , Kim Taesoo , Reynolds John R. , Amassian Aram , Gundogdu Kenan , Ade Harald , So Franky
Published: January 2020

Understanding the correlation between polymer aggregation, miscibility, and device performance is important to establish a set of chemistry design rules for donor polymers with nonfullerene acceptors (NFAs). Employing a donor polymer with strong temperature‐dependent aggregation, namely PffBT4T‐2OD [poly[(5,6‐difluoro‐2,1,3‐benzothiadiazol‐4,7‐diyl)‐alt‐(3,3″′‐di(2‐octyldodecyl)‐2,2′;5′,2″;5″,2″′‐quaterthiophen‐5,5‐diyl)], also known as PCE‐11 as a base polymer, five copolymer derivatives having a different thiophene linker composition are blended with the common NFA O‐IDTBR to investigate their photovoltaic performance. While the donor polymers have similar optoelectronic properties, it is found that the device power conversion efficiency changes drastically from 1.8% to 8.7% as a function of thiophene content in the donor polymer. Results of structural characterization show that polymer aggregation and miscibility with O‐IDTBR are a strong function of the chemical composition, leading to different donor–acceptor blend morphology. Polymers having a strong tendency to aggregate are found to undergo fast aggregation prior to liquid–liquid phase separation and have a higher miscibility with NFA. These properties result in smaller mixed donor–acceptor domains, stronger PL quenching, and more efficient exciton dissociation in the resulting cells. This work indicates the importance of both polymer aggregation and donor–acceptor interaction on the formation of bulk heterojunctions in polymer:NFA blends.
A Critical Review of Machine Learning of Energy Materials
Authors: Chen Chi , Zuo Yunxing , Ye Weike , Li Xiangguo , Deng Zhi , Ong Shyue Ping
Published: January 2020

Machine learning (ML) is rapidly revolutionizing many fields and is starting to change landscapes for physics and chemistry. With its ability to solve complex tasks autonomously, ML is being exploited as a radically new way to help find material correlations, understand materials chemistry, and accelerate the discovery of materials. Here, an in‐depth review of the application of ML to energy materials, including rechargeable alkali‐ion batteries, photovoltaics, catalysts, thermoelectrics, piezoelectrics, and superconductors, is presented. A conceptual framework is first provided for ML in materials science, with a broad overview of different ML techniques as well as best practices. This is followed by a critical discussion of how ML is applied in energy materials. This review is concluded with the perspectives on major challenges and opportunities in this exciting field.
Ultraviolet Photoemission Spectroscopy and Kelvin Probe Measurements on Metal Halide Perovskites: Advantages and Pitfalls
Authors: Zhang Fengyu , Silver Scott H. , Noel Nakita K. , Ullrich Florian , Rand Barry P. , Kahn Antoine
Published: January 2020

In this essay, a case study is presented on the electronic structure of several metal halide perovskites (MHP) using Kelvin probe (KP)‐based surface photovoltage (SPV) measurements and ultraviolet photoemission spectroscopy (UPS) to demonstrate the advantages, but also the pitfalls, of using these techniques to characterize the surfaces of these materials. The first part addresses the loss of halide species from perovskite surfaces upon supragap illumination in vacuum. This has the potential to cause both a long‐term alteration of the sample work function and a modification of the KP tip during SPV measurements. If undetected, this leads to a misinterpretation of the MHP surface potential. The second part illustrates the difficulties in determining the valence band maximum (VBM) of MHP surfaces with UPS and stresses the importance of taking into account the low density of states at the VBM edge. Given this circumstance, specific care must be taken to eliminate measurement artifacts in order to ascertain the presence or absence of low densities of electronic gap states above the VBM. This essay also highlights issues such as film degradation, nonequilibrium situations (e.g., SPV), and satellite emissions, which occur during photoemission spectroscopy.
Eliminating Transition Metal Migration and Anionic Redox to Understand Voltage Hysteresis of Lithium‐Rich Layered Oxides
Authors: Han Miao , Jiao Junyu , Liu Zepeng , Shen Xi , Zhang Qinghua , Lin Hong‐Ji , Chen Chien‐Te , Kong Qingyu , Pang Wei Kong , Guo Zaiping , Yu Richeng , Gu Lin , Hu Zhiwei , Wang Zhaoxiang , Chen Liquan
Published: January 2020

Lithium‐rich layered oxides are promising candidate cathode materials for the Li‐ion batteries with energy densities above 300 Wh kg−1. However, issues such as the voltage hysteresis and decay hinder their commercial applications. Due to the entanglement of the transition metal (TM) migration and the anionic redox upon lithium extraction at high potentials, it is difficult to recognize the origin of these issues in conventional Li‐rich layered oxides. Herein, Li2MoO3 is chosen since prototype material to uncover the reason for the voltage hysteresis as the TM migration and anionic redox can be eliminated below 3.6 V versus Li+/Li in this material. On the basis of comprehensive investigations by neutron powder diffraction, scanning transmission electron microscopy, synchrotron X‐ray absorption spectroscopy, and density functional theory calculations, it is clarified that the ordering–disordering transformation of the Mo3O13 clusters induced by the intralayer Mo migration is responsible for the voltage hysteresis in the first cycle; the hysteresis can take place even without the anionic redox or the interlayer Mo migration. A similar suggestion is drawn for its iso‐structured Li2RuO3 (C2/c). These findings are useful for understanding of the voltage hysteresis in other complicated Li‐rich layered oxides.
Engineering Electronic Structure of Stannous Sulfide by Amino‐Functionalized Carbon: Toward Efficient Electrocatalytic Reduction of CO2 to Formate
Authors: Chen Zhipeng , Zhang Xinxin , Jiao Mingyang , Mou Kaiwen , Zhang Xiangping , Liu Licheng
Published: January 2020

Engineering electronic structure to enhance the binding energies of reaction intermediates in order to achieve a high partial current density can lead to increased yield of target products. Herein, amino‐functionalized carbon is used to regulate the electronic structure of tin‐based catalysts to enhance activity of CO2 electroreduction. The hollow nanotubes composed of SnS (stannous sulfide) nanosheets are modified with amino‐functionalized carbon layers, achieving a highest formate Faraday efficiency of 92.6% and a remarkable formate partial current density of 41.1 mA cm−2 (a total current density of 52.1 mA cm−2) at a moderate overpotential of 0.9 V versus reversible hydrogen electrode, as well as a good stability. Density functional theory calculations demonstrate that the superior activity is attributed to the synergistic effect among SnS and Aminated‐C in increasing the adsorption energies of the key intermediates and accelerating the charge transfer rate.
Large Power Amplification in Magneto‐Mechano‐Electric Harvesters through Distributed Forcing
Authors: Sriramdas Rammohan , Kang Min‐Gyu , Meng Miao , Kiani Mehdi , Ryu Jungho , Sanghadasa Mohan , Priya Shashank
Published: January 2020

Energy harvesting from extremely low frequency magnetic fields using magneto‐mechano‐electric (MME) harvesters enables wireless power transfer for operating Internet of Things (IoT) devices. The MME harvesters are designed to resonate at a fixed frequency by absorbing AC magnetic fields through a composite cantilever comprising of piezoelectric and magnetostrictive materials, and a permanent magnetic tip mass. However, this harvester architecture limits power generation because volume of the magnetic end mass is closely coupled with the resonance frequency of the device structure. Here, a method is demonstrated for maintaining the resonance frequency of the MME harvesters under all operating conditions (e.g., 60 Hz, standard frequency of electricity in many countries) while simultaneously enhancing the output power generation. By distributing the magnetic mass over the beam, the output power of the harvester is significantly enhanced at a constant resonance frequency. The MME harvester with distributed forcing shows 280% improvement in the power generation compared with a traditional architecture. The generated power is shown to be sufficient to power eight different onboard sensors with wireless data transmission integrated on a drone. These results demonstrate the promise of MME energy harvesters for powering wireless communication and IoT sensors.
Drip irrigation with organic fertilizer application improved soil quality and fruit yield
Authors: Li Fayong , Yuan Chengyu , Lao Dongqing , Yao Baolin , Hu Xuefei , You Yongjun , Wang Long , Sun Sanmin , Liang Xinqiang
Published: January 2020

Irrigation and fertilization management are important for controlling agricultural soil salinity and increasing productivity in extremely arid regions. The objective of this research was to evaluate the effects of long‐term drip irrigation and organic fertilizer application on soil salinity, fruit quality and yield of jujube [Ziziphus ziziphus (L.) Karst]. We established a 7‐yr field experiment in a desert‐oasis area in Northwest China. Six treatments were performed: CK (conventional irrigation, no fertilizer), CIMF (conventional irrigation, mineral fertilizer), CIOF (conventional irrigation, organic fertilizer), DI (drip irrigation, no fertilizer), DIMF (drip irrigation, mineral fertilizer), and DIOF (drip irrigation, organic fertilizer). The results showed that soil organic carbon (SOC) concentration in soil treated with organic fertilizer increased gradually over years. Treatment DIOF favored the accumulation of SOC with the highest content and stock after 7 yr. Lower salt content in root zone was found in DIOF after 7 yr. The yield of DIOF increased annually and reached an equilibrium level after the fourth year (14.88 to 16.69 Mg ha−1). Total carbohydrate and vitamin C (Vc) of DIOF of fruit were all significantly higher than CIOF and DIMF. The boosted regression tree showed that SOC content had the highest relative contribution rate to jujube yield. Path analysis identified the most important factor affecting SOC in the drip‐fertigation system was the input of organic fertilizer, with path coefficient 0.65. Long‐term combination of drip irrigation and organic fertilizer application would be an effective strategy maintaining productivity and improve fruit quality in extremely arid areas.
Developing an in vivo porcine model of duct‐to‐mucosa pancreaticojejunostomy (Yonsei‐PJDTM)
Authors: Choi Munseok , Kang Chang Moo
Published: January 2020

Laparoscopic pancreaticoduodenectomy (LPD) is technically feasible, but its safety is still controversial. Pancreas texture and the small size of the main pancreatic duct indicate laparoscopic pancreaticoduodenectomy (LPD) as a challenging procedure. Thus, LPD could be a risk factor for postoperative pancreatic fistula (POPF), longer hospital stay, and delayed adjuvant chemotherapy that affects long‐term oncologic outcome. So, it is important to promote education on LPD especially techniques for pancreaticojejunostomy. A porcine model for duct‐to‐mucosa pancreaticojejunostomy (PJ) (Yonsei‐PJDTM) was developed, and details of the model will be described in this report.
Stateful In‐Memory Logic System and Its Practical Implementation in a TaOx‐Based Bipolar‐Type Memristive Crossbar Array
Authors: Kim Young Seok , Son Myeong Won , Song Hanchan , Park Juseong , An Jangho , Jeon Jae Bum , Kim Geun Young , Son Seoil , Kim Kyung Min
Published: January 2020

Memristive stateful logic enables energy‐ and cost‐efficient in‐memory computing, which is desirable for edge computing in the coming Internet of Things  (IoT) era. Researchers have recently developed various stateful logic gates and have shown viable computing applications based on ideal memristive characteristics. However, few studies have demonstrated a system‐level in‐memory computing operation that can address the practical issues affecting device realization. Herein, a practically viable stateful logic device based on a 1‐transistor−1‐memristor (1T1M) array structure is proposed, considering the inherently stochastic memristor characteristics. Details on how to select the viable stateful logic gates in a given memristor are shown, and as an example of logic cascading, they are implemented in a device to operate a multibit carry look‐ahead adder. Then, an in‐memory computing layout that can perform all of the computing functions—data storing, transferring, and executing—inside the memory, addressing data traffic issues, is suggested. Finally, a software/hardware mixed stateful logic emulator that can virtually mimic array‐level in‐memory computing hardware based on cell‐level memristive characteristics is demonstrated.
Leopard predation on gelada monkeys at Guassa, Ethiopia
Authors: Lin Bing , Foxfoot Iris R. , Miller Carrie M. , Venkatamaran Vivek V. , Kerby Jeffrey T. , Bechtold Emily K. , Kellogg Bryce S. , Nguyen Nga , Fashing Peter J.
Published: January 2020

Predation is widely believed to exert strong selective pressure on primate behavior and ecology but is difficult to study and rarely observed. In this study, we describe seven encounters between lone wild leopards (Panthera pardus) and herds of geladas (Theropithecus gelada) over a 6‐year period in an intact Afroalpine grassland ecosystem at the Guassa Community Conservation Area, Ethiopia. Three encounters consisted of attempted predation on geladas by leopards, one of which was successful. All three attacks occurred in low‐visibility microhabitats (dominated by tussock graminoids, mima mounds, or tall shrubs) that provided leopards with hidden viewsheds from which to ambush geladas. An additional four encounters did not result in an attempted attack but still document the consistently fearful responses of geladas to leopards. In encounters with leopards, geladas typically gave alarm calls (n = 7 of 7 encounters), reduced interindividual distances (n = 5), and collectively fled towards or remained at their sleeping cliffs (n = 7), the only significant refugia in the open‐country habitat at Guassa. Geladas did not engage in mobbing behavior towards leopards. Encounters with leopards tended to occur on days when gelada herd sizes were small, raising the possibility that leopards, as ambush hunters, might stalk geladas on days when fewer eyes and ears make them less likely to be detected. We compare the behavioral responses of geladas to leopards at Guassa with those previously reported at Arsi and the Simien Mountains and discuss how gelada vulnerability and responses to leopards compare with those of other primate species living in habitats containing more refugia. Lastly, we briefly consider how living in multilevel societies may represent an adaptive response by geladas and other open‐country primates to predation pressure from leopards and other large carnivores.
Lactating Coquerel's sifaka (Propithecus coquereli) exhibit reduced stress responses in comparison to males and nonlactating females
Authors: Ross Abigail C.
Published: January 2020

Cortisol is a glucocorticoid hormone that plays a principal role in metabolic function and stress responses in wild primates. Stressors are ubiquitous in environments and elicit a variety of physiological and behavioral responses. While stress responses are adaptive in the short‐term, they can have negative effects when experienced over longer durations. As a physiological stressor, the process of lactation is an energetically expensive activity for mammals. Milk production increases water loss and increased hydration demands are amplified in mammalian species inhabiting xeric habitats, including lemur species living in northwestern Madagascar—the region for this research work. Here, sifakas give birth during the dry season (May–October) and wean infants during the subsequent wet season (November–April). The author collected fecal samples during the 24 weeks following infant births in 10 groups of Coquerel's sifaka in Ankarafantsika Park, Madagascar. The author analyzed the samples by comparing the first 12‐week time block to the second 12‐week time block, which corresponded to the dry and the beginning of the wet seasons, respectively. Analyses were based on 375 samples collected over two birth seasons (2010 and 2011). A linear mixed model determined the relationships between reproductive class and temporal cortisol variation. The three reproductive classes had significantly different cortisol concentrations. Lactating females had lower cortisol than adult males and nonlactating females in all weeks postnatal. Males had significantly higher cortisol in weeks 13–24 relative to weeks 1–12. Examining seasonal changes in cortisol concentrations demonstrates how lemurs respond physiologically to the energetic constraints of lactation during the critical life history stage of infant development.
Dynamically Induced Excitonic Instability in Pumped Dirac Materials
Authors: Pertsova Anna , Balatsky Alexander V.
Published: January 2020

Driven and non‐equilibrium quantum states of matter have attracted growing interest in both theoretical and experimental studies in condensed matter physics. Recent progress in realizing transient collective states in driven or pumped Dirac materials (DMs) is reviewed herein. In particular, the focus is on optically pumped DMs which are a promising platform for transient excitonic instabilities. Optical pumping combined with the linear (Dirac) dispersion of the electronic spectrum offers a knob for tuning the effective interaction between the photoexcited electrons and holes, and thus provides a way of reducing the critical coupling for excitonic instability. As a result, a transient excitonic condensate could be achieved in a pumped DM while it is not feasible in equilibrium. A unifying theoretical framework is provided for describing transient collective states in 2D and 3D DMs. The experimental signatures are described and numerical estimates of the size of the dynamically induced excitonic gaps and the values of the critical temperatures for several specific systems, are summarized. In addition, general guidelines for identifying promising material candidates are discussed. Finally, comments are provided regarding recent experimental efforts in realizing transient excitonic condensate in pumped DMs, and outstanding issues and possible future directions are outlined.
Systemic Brain Delivery of Antisense Oligonucleotides across the Blood–Brain Barrier with a Glucose‐Coated Polymeric Nanocarrier
Authors: Min Hyun Su , Kim Hyun Jin , Naito Mitsuru , Ogura Satomi , Toh Kazuko , Hayashi Kotaro , Kim Beob Soo , Fukushima Shigeto , Anraku Yasutaka , Miyata Kanjiro , Kataoka Kazunori
Published: January 2020

Current antisense oligonucleotide (ASO) therapies for the treatment of central nervous system (CNS) disorders are performed through invasive administration, thereby placing a major burden on patients. To alleviate this burden, we herein report systemic ASO delivery to the brain by crossing the blood–brain barrier using glycemic control as an external trigger. Glucose‐coated polymeric nanocarriers, which can be bound by glucose transporter‐1 expressed on the brain capillary endothelial cells, are designed for stable encapsulation of ASOs, with a particle size of about 45 nm and an adequate glucose‐ligand density. The optimized nanocarrier efficiently accumulates in the brain tissue 1 h after intravenous administration and exhibits significant knockdown of a target long non‐coding RNA in various brain regions, including the cerebral cortex and hippocampus. These results demonstrate that the glucose‐modified polymeric nanocarriers enable noninvasive ASO administration to the brain for the treatment of CNS disorders.
[11C]Carbonyl Difluoride—a New and Highly Efficient [11C]Carbonyl Group Transfer Agent
Authors: Jakobsson Jimmy E. , Lu Shuiyu , Telu Sanjay , Pike Victor W.
Published: January 2020

Herein, the synthesis and use of [11C]carbonyl difluoride for labeling heterocycles with [11C]carbonyl groups in high molar activity is described. A very mild single‐pass gas‐phase conversion of [11C]carbon monoxide into [11C]carbonyl difluoride over silver(II) fluoride provides easy access to this new synthon in robust quantitative yield for labeling a broad range of cyclic substrates, for example, imidazolidin‐2‐ones, thiazolidin‐2‐ones, and oxazolidin‐2‐ones. Labeling reactions may utilize close‐to‐stoichiometric precursor quantities and short reaction times at room temperature in a wide range of solvents while also showing high water tolerability. The overall radiosynthesis protocol is both simple and reproducible. The required apparatus can be constructed from widely available parts and is therefore well suited to be automated for PET radiotracer production. We foresee that this straightforward method will gain wide acceptance for PET radiotracer syntheses across the radiochemistry community.
A Chiral Reduced‐Dimension Perovskite for an Efficient Flexible Circularly Polarized Light Photodetector
Authors: Wang Lin , Xue Yongxiang , Cui Minghuan , Huang Yanmin , Xu Hongyu , Qin Chaochao , Yang Jien , Dai Haitao , Yuan Mingjian
Published: January 2020

Chiral quasi‐2D perovskite single crystals (SCs) were investigated for their circular polarized light (CPL) detecting capability. Quasi‐2D chiral perovskites, [(R)‐β‐MPA]2MAPb2I7 ((R)‐β‐MPA=(R)‐(+)‐β‐methylphenethylamine, MA=methylammonium), have intrinsic chirality and the capability to distinguish different polarization states of CPL photons. Corresponding quasi‐2D SCs CPL photodetector exhibit excellent detection performance. In particular, our device responsivity is almost one order of magnitude higher than the reported 2D perovskite CPL detectors to date. The crystallization dynamics of the film were modulated to facilitate its carrier transport. Parallel oriented perovskite films with a homogeneous energy landscape is crucial to maximize the carrier collection efficiency. The photodetector also exhibits superior mechanical flexibility and durability, representing a promising candidate for sensitive and robust CPL photodetectors.
Tandemreaktionen aus anionischer Oxy‐Cope‐Umlagerung und Oxygenierung als vielseitiger Zugang zu verschiedenartigen Gerüsten
Authors: Šimek Michal , Bártová Kateřina , Pohl Radek , Císařová Ivana , Jahn Ullrich
Published: January 2020

Tandemreaktionen aus anionischer Oxy‐Cope‐Umlagerung und Radikaloxygenierung ergeben δ,ϵ‐ungesättigte α‐(Aminoxy)carbonylverbindungen, die sich als vielseitige Vorläufer für verschiedenartige Verbindungsklassen eignen. Funktionalisierte Carbocyclen werden durch sehr seltene 5‐endo‐trig, aber auch gebräuchlichere 5‐exo‐trig Radikalcyclisierungen durch Nutzung des persistenten Radikaleffekts erhalten. Die Tandemreaktionen können durch hochdiastereoselektive Allylierungs‐ oder Reduktionsschritte erweitert werden, die zu komplexen Gerüsten führen.
Stable Radical Cation and Dication of an N‐Heterocyclic Carbene Stabilized Digallene: Synthesis, Characterization and Reactivity
Authors: Feng Zhongtao , Fang Yong , Ruan Huapeng , Zhao Yue , Tan Gengwen , Wang Xinping
Published: January 2020

One‐ and two‐electron oxidation of a digallene stabilized by an N‐heterocyclic carbene afforded the first stable gallium‐based radical cation and dication salts, respectively. Structural analysis and theoretical calculations reveal that the oxidation occurs at the Ga=Ga double bond, leading to removal of π electrons of the double bond and a decrease of the bond order. The spin density of the radical cation mainly locates at the two gallium centers as demonstrated by EPR spectroscopy and theoretical calculations. Moreover, the reactivity of the radical cation salt toward nBu3SnH and cyclo‐S8 was studied; a digallium–hydride cation salt containing a Ga−Ga single bond and a gallium sulfide cluster bearing an unprecedented ladder‐like Ga4S4 core structure were obtained, respectively.
Using the Secondary PH/BH Functional Groups of an Active Geminal Frustrated Lewis Pair for Carbon Monoxide Reduction and Reactions with Nitriles and Isonitriles
Authors: Li Jun , Mück‐Lichtenfeld Christian , Daniliuc Constantin G. , Kehr Gerald , Erker Gerhard
Published: January 2020

Reaction of the secondary alkynyl(Mes*)PH phosphane2with (Fmes)BH2⋅SMe2gives the geminal PH/BH frustrated Lewis pair (FLP)3. The PH and the BH functions are jointly used in the reduction of carbon monoxide under mild reaction conditions to give the [P]‐CH2‐O‐[B] product. A subsequent cycloaddition sequence results in the liberation of formaldehyde. The FLP3reacts with benzonitrile to give a P‐benzamidine, and it couples two isonitriles at the FLP framework.
Tandem Anionic oxy‐Cope Rearrangement/Oxygenation Reactions as a Versatile Method for Approaching Diverse Scaffolds
Authors: Šimek Michal , Bártová Kateřina , Pohl Radek , Císařová Ivana , Jahn Ullrich
Published: January 2020

Tandem anionic oxy‐Cope rearrangement/radical oxygenation reactions provide δ,ϵ‐unsaturated α‐(aminoxy) carbonyl compounds, which serve as convenient precursors to diverse compound classes. Functionalized carbocycles are accessible by very rare all‐carbon 5‐endo‐trig cyclizations, but also common 5‐exo‐trig radical cyclizations, based on the persistent radical effect. The tandem reactions can be further extended by highly diastereoselective allylation or reduction steps to give complex scaffolds.
Intrinsic Facet‐Dependent Reactivity of Well‐Defined BiOBr Nanosheets on Photocatalytic Water Splitting
Authors: Shi Ming , Li Guanna , Li Jianming , Jin Xu , Tao Xiaoping , Zeng Bin , Pidko Evgeny A. , Li Rengui , Li Can
Published: January 2020

Surface atomic arrangement and coordination of photocatalysts highly exposed to different crystal facets significantly affect the photoreactivity. However, controversies on the true photoreactivity of a specific facet in heterogeneous photocatalysis still exits. Herein, we exemplified well‐defined BiOBr nanosheets dominating with respective facets, (001) and (010), to track the reactivity of crystal facets for photocatalytic water splitting. The real photoreactivity of BiOBr‐(001) were evidenced to be significantly higher than BiOBr‐(010) for both hydrogen production and oxygen evolution reactions. Further in situ photochemical probing studies verified the distinct reactivity is not only owing to the highly exposed facets, but dominated by the co‐exposing facets, leading to an efficient spatial separation of photogenerated charges and further making the oxidation and reduction reactions separately occur with different reaction rates, which ordains the fate of the true photoreactivity.
Fast Titanium‐Catalyzed Hydroaminomethylation of Alkenes and the Formal Conversion of Methylamine
Authors: Bielefeld Jens , Doye Sven
Published: January 2020

The scientific interest in catalytic hydroaminoalkylation reactions of alkenes has vastly increased over the past decade, but these reactions have struggled to become a viable option for general laboratory or industrial use because of reaction times of several days. The titanium‐based catalytic system introduced in this work not only reduces the reaction time by several orders of magnitude, into the range of minutes, but the catalyst is also demonstrated to be easily available from common starting materials, at a cost of approximately 1 € per millimole of catalyst. We were also able to formally perform C−H activation of methylamine and achieve coupling to a broad variety of alkenes, through silyl protection of the amine and simple deprotection by water.
CuII@PAA/PVC mesoporous fibers: A hybrid wedding as a high‐performance versatile heterogeneous catalyst for A3, KA2, and decarboxylative A3 reactions
Authors: Jiang Wei , Zhou Yuemin , Sun Wei , Li Yiqun
Published: January 2020

Efforts made on the development of a novel, simple, cost‐effective, and efficient approach to fabricate a copper catalyst immobilized on mesoporous poly (acrylic acid)/poly (vinyl chloride) hybrid fibers (CuII@PAA/PVC) for versatile catalytic applications in A3, KA2, and decarboxylative A3 couplings has been described in this present work. The characterization of the mesoporous hybrid fibers was well performed by BET, FTIR, SEM, EDX, XPS, and TGA techniques. The pore structure and surface area were calculated by using BET measurement analysis. The obtained mesoporous CuII@PAA/PVC fibers exert high catalytic performance in the synthesis of propargylamines via one‐pot A3, KA2, and decarboxylative A3 reactions over a series of substrates without employing expensive ligands or inert atmosphere. The active Cu2+ species chelating with carboxylate groups in PAA/PVC hybrid fibers plays a key role in the catalysis. Meanwhile, the unique mesoporous structure and fiber morphology facilitate a better mass transfer and enlarge its contact area with substrates in the course of a reaction. Moreover, the Cu2+–carboxylate chelation could suppress the leaching of active Cu2+ species from the catalyst and thus lead to the catalyst has excellent performance and good durability as well as reusability.