bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study on Rain Rate Prediction of Southwestern Nigeria
Authors: Abiola Semire Folasade , Adekunle Adeyanju , Olayimika Abolade Robert
Published: January 2020

Rainfall parameters can be utilized to investigate the effect of climate change through scientific methods. However, data on rainfall rate exceeded for a fraction of an average year is grossly unavailable over Nigeria’s climate, thereby diminishing the capability of existing models to adequately estimate the effect of degradation due to rain. Hence, more accurate estimation is required for better predictions. Rainfall volume data for six different locations in the south-western region of Nigeria were obtained for rain rate computation using Semire and Rosmiwati model. The curve-fitted Cumulative Distribution Functions were compared with the ITU-R rain rate model (Recommendation P.837-6) and compensation function was obtained using error analysis while the performance was evaluated with respect to existing models using Chi-square, and Percentage Error and Root Mean Square Error (RMSE) metrics. The outcome of this study can be adopted for better understanding of spatial rainfall intensity in this region and other climatic zones of similar rainfall characteristics.
Nanostructured Fe–Cr–W Steel Exhibits Enhanced Resistance to Self‐Ion Irradiation
Authors: Mazilkin Andrey , Ivanisenko Yulia , Sauvage Xavier , Etienne Auriane , Radiguet Bertrand , Valiev Ruslan , Abramova Marina , Enikeev Nariman
Published: January 2020

Herein, a study on radiation‐induced defect structures in a reactor Fe–14Cr–1W (wt%) steel with grain sizes of 5 μm and 110 nm is presented. Self‐ion irradiation of the steel in both states is conducted with a damage dose of 10 dpa. Microstructure characterization shows that the density of intragranular radiation‐induced dislocations is significantly lower in case of the nanostructured material. From the results obtained, it follows that microstructure refinement to a grain size of about 100 nm can be effectively used to approach a problem of higher defect production rate in Fe–Cr steels driven by irradiation and to produce alloys with significantly enhanced mechanical performance as well as radiation tolerance.
Second Generation Nanoporous Silicon Nitride Membranes for High Toxin Clearance and Small Format Hemodialysis
Authors: Hill Kayli , Walker Samuel N. , Salminen Alec , Chung Hung L. , Li Xunzhi , Ezzat Bahie , Miller Joshua J. , DesOrmeaux Jon‐Paul S. , Zhang Jingkai , Hayden Andrew , Burgin Tucker , Piraino Lindsay , May Marina N. , Gaborski Thomas R. , Roussie James A. , Taylor Jeremy , DiVincenti Louis , Shestopalov Alexander A. , McGrath James L. , Johnson Dean G.
Published: January 2020

Conventional hemodialysis (HD) uses floor‐standing instruments and bulky dialysis cartridges containing ≈2 m2 of 10 micrometer thick, tortuous‐path membranes. Portable and wearable HD systems can improve outcomes for patients with end‐stage renal disease by facilitating more frequent, longer dialysis at home, providing more physiological toxin clearance. Developing devices with these benefits requires highly efficient membranes to clear clinically relevant toxins in small formats. Here, the ability of ultrathin (<100 nm) silicon‐nitride‐based membranes to reduce the membrane area required to clear toxins by orders of magnitude is shown. Advanced fabrication methods are introduced that produce nanoporous silicon nitride membranes (NPN‐O) that are two times stronger than the original nanoporous nitride materials (NPN) and feature pore sizes appropriate for middle‐weight serum toxin removal. Single‐pass benchtop studies with NPN‐O (1.4 mm2) demonstrate the extraordinary clearance potential of these membranes (105 mL min−1 m−2), and their intrinsic hemocompatibility. Results of benchtop studies with nanomembranes, and 4 h dialysis of uremic rats, indicate that NPN‐O can reduce the membrane area required for hemodialysis by two orders of magnitude, suggesting the performance and robustness needed to enable small‐format hemodialysis, a milestone in the development of small‐format hemodialysis systems.
Synthetic Polymers Provide a Robust Substrate for Functional Neuron Culture
Authors: Zhang Yichuan , Venkateswaran Seshasailam , Higuera Gustavo A. , Nath Suvra , Shpak Guy , Matray Jeffrey , Fratila‐Apachitei Lidy E. , Zadpoor Amir A. , Kushner Steven A. , Bradley Mark , De Zeeuw Chris I.
Published: January 2020

Substrates for neuron culture and implantation are required to be both biocompatible and display surface compositions that support cell attachment, growth, differentiation, and neural activity. Laminin, a naturally occurring extracellular matrix protein is the most widely used substrate for neuron culture and fulfills some of these requirements, however, it is expensive, unstable (compared to synthetic materials), and prone to batch‐to‐batch variation. This study uses a high‐throughput polymer screening approach to identify synthetic polymers that supports the in vitro culture of primary mouse cerebellar neurons. This allows the identification of materials that enable primary cell attachment with high viability even under “serum‐free” conditions, with materials that support both primary cells and neural progenitor cell attachment with high levels of neuronal biomarker expression, while promoting progenitor cell maturation to neurons.
Distinguishing Specific CXCL12 Isoforms on Their Angiogenesis and Vascular Permeability Promoting Properties
Authors: Chang Chia‐Wen , Seibel Alex J. , Avendano Alex , Cortes‐Medina Marcos G. , Song Jonathan W.
Published: January 2020

Angiogenesis is associated with increased vessel sprouting and permeability. Important mediators of these angiogenic responses include local environment of signaling molecules and supporting extracellular matrix (ECM). However, dissecting the interplay of these instructive signals in vivo with multiple cells and extracellular molecules remains a central challenge. Here, microfluidic biomimicry is integrated with 3D ECM hydrogels that are well‐characterized for molecular‐binding and mechanical properties to reconstitute vessel‐like analogues in vitro. This study focuses on three distinct isoforms of the pro‐metastatic chemokine CXCL12. In collagen‐only hydrogel, CXCL12‐α is the most potent isoform in promoting sprouting and permeability, followed by CXCL12‐β and CXCL12‐γ. Strikingly, addition of hyaluronan (HA), a large and negatively charged glycosaminoglycan, with collagen matrices selectively increases vessel sprouting and permeability conferred by CXCL12‐γ. This outcome is supported by the measured binding affinities to collagen/HA ECM, suggesting that negatively charged HA increases the binding of CXCL12‐γ to augment its angiogenic potency. Moreover, it is shown that addition of HA to collagen matrices on its own decreases vessel sprouting and permeability, and these responses are nullified by blocking the HA receptor CD44. Collectively, these results demonstrate that differences in binding to extracellular HA help underlie CXCL12 isoform‐specific responses toward directing angiogenesis.
On Supramolecular Self‐Assembly: Interview with Samuel Stupp
Authors: Stupp Samuel I.
Published: January 2020

Ranging from 2D assemblies to peptide amphiphile‐based biomaterials, Prof. Samuel Stupp and his team have enriched the scientific community with many breakthroughs in the field of supramolecular self‐assembly. This Interview offers the unique possibility to share some highlights along his journey, providing also a glimpse to his vision of the future of supramolecular chemistry. Interdisciplinarity is an integral part of Prof. Stupp's research philosophy, and, using his own words, “it is the only way to understand the complex universe around us and help society along the way”. What a great guideline to us all!
Tailoring C60 for Efficient Inorganic CsPbI2Br Perovskite Solar Cells and Modules
Authors: Liu Chong , Yang Yuzhao , Zhang Cuiling , Wu Shaohang , Wei Liyu , Guo Fei , Arumugam Gowri Manohari , Hu Jinlong , Liu Xingyuan , Lin Jie , Schropp Ruud E. I. , Mai Yaohua
Published: January 2020

Although inorganic perovskite solar cells (PSCs) are promising in thermal stability, their large open‐circuit voltage (VOC) deficit and difficulty in large‐area preparation still limit their development toward commercialization. The present work tailors C60 via a codoping strategy to construct an efficient electron‐transporting layer (ETL), leading to a significant improvement in VOC of the inverted inorganic CsPbI2Br PSC. Specifically, tris(pentafluorophenyl)borane (TPFPB) is introduced as a dopant to lower the lowest unoccupied molecular orbital (LUMO) level of the C60 layer by forming a Lewis acidic adduct. The enlarged free energy difference provides a favorable enhancement in electron injection and thereby reduces charge recombination. Subsequently, a nonhygroscopic lithium salt (LiClO4) is added to increase electron mobility and conductivity of the film, leading to a reduction in the device hysteresis and facilitating the fabrication of a large‐area device. Finally, the as‐optimized inorganic CsPbI2Br PSCs gain a champion power conversion efficiency (PCE) of 15.19%, with a stabilized power output (SPO) of 14.21% (0.09 cm2). More importantly, this work also demonstrates a record PCE of 14.44% for large‐area inorganic CsPbI2Br PSCs (1.0 cm2) and reports the first inorganic perovskite solar module with the excellent efficiency exceeding 12% (10.92 cm2) by a self‐developed quasi‐curved heating method.
One‐Step‐Printed, Highly Sensitive, Textile‐Based, Tunable Performance Strain Sensors for Human Motion Detection
Authors: Luo Chengsheng , Tian Bin , Liu Qun , Feng Yu , Wu Wei
Published: January 2020

Wearable strain sensors have attracted a lot of interests due to their unlimited prospects in applications such as human motion detections, electronic skin, and human–computer interactions. However, the complex manufacturing methods are generally used to fabricate the strain sensors with wide sensing ranges and high sensitivity. Herein, a high‐performance textile‐based strain sensor (TSS) is fabricated by one‐step screen‐printing method via transferring the silver nanowires ink onto a stretchable textile. Through designing the screen plate with various patterns, the optimized TSSs with different sensing ranges and sensitivity can be achieved simultaneously. Among them, a straight line‐structural TSS (with a width of 2 mm) exhibits a wide workable strain range of 120%, high gauge factor of 216, and superior durability (more than 2000 stretching/releasing cycles). As flexible wearable devices, these TSSs are used to monitor human joint motion, prefiguring the various applications in human health detection, soft robots, intelligent devices, etc.
A Tunable Metasurface with Switchable Functionalities: From Perfect Transparency to Perfect Absorption
Authors: Li Yue , Lin Jing , Guo Huijie , Sun Wujiong , Xiao Shiyi , Zhou Lei
Published: January 2020

A thin screen exhibiting dynamically switchable transmission/absorption functionalities is highly desired in practice. However, a trilayer transmissive metasurface with active elements controlled in a uniform manner cannot exhibit independently controlled transmission and absorption properties due to intriguing interplays between the scattering and absorbing properties in systems exhibiting inversion symmetries. This motivates to employ the coupled‐mode theory to establish a generic phase diagram for such transmissive metasurfaces with active elements loaded in different layers tuned independently and to guide researchers design tunable metadevices with completely decoupled transmission/absorption responses. Based on such a phase diagram, a microwave metasurface is designed/fabricated with PIN diodes incorporated, and it is experimentally demonstrated that its functionality can switch from perfect transparency to perfect absorption, controlled by external voltages applied across the diodes. In addition to finding immediate applications in practice (e.g., smart radomes), the results of this study also provide a new type of tunable meta‐atom for building metasurfaces with flexible wave‐front control abilities.
Low‐Loss Hybrid High‐Index Dielectric Particles on a Mirror for Extreme Light Confinement
Authors: Maimaiti Aili , Patra Partha Pratim , Jones Steven , Antosiewicz Tomasz J. , Verre Ruggero
Published: January 2020

The quest for enhancing light–matter interactions at the nanoscale has led scientists to nanophotonic systems that support the smallest possible modes, which are currently realized via particle‐on‐mirror (PoM) geometries using plasmonic particles. The drawback of metallic PoM systems is the large absorption/scattering ratio due to the significant Ohmic losses inherent to plasmonics. Here, an alternative dielectric PoM composed of a high‐index dielectric nanodisk on top of a metallic mirror is realized. Custom‐shaped high‐quality dielectric colloidal nanoparticles are fabricated and dispersed on a mirror to fully unlock the potential of PoM systems. This hybrid device combines the large field enhancement and extreme localization of plasmonic systems with the low absorption of dielectric nanoresonators. By means of far‐field scattering and near‐field cathodoluminescence spectroscopy, the nature of the modes supported by the hybrid PoM are revealed. Utilizing enhanced spectroscopies, such as Raman and fluorescence, these hybrid‐PoM systems are used in proof‐of‐principle applications. A comparison with Au antennas indicates that the hybrid PoM system presents efficiencies and optical characteristics comparable or superior to those of more conventional purely plasmonic systems, opening new avenues for low‐loss light control at the deep nanoscale level.
All‐Rounder Low‐Cost Dopant‐Free D‐A‐D Hole‐Transporting Materials for Efficient Indoor and Outdoor Performance of Perovskite Solar Cells
Authors: Pham Hong Duc , Jain Sagar M. , Li Meng , Wang Zhao‐Kui , Manzhos Sergei , Feron Krishna , Pitchaimuthu Sudhagar , Liu Zhiyong , Motta Nunzio , Durrant James R. , Sonar Prashant
Published: January 2020

A novel biphenyl fumaronitrile as an acceptor and triphenylamine as donor conjugated building blocks are used for the first time to successfully synthesize donor–acceptor–donor molecule (D‐A‐D) 2,3‐bis(4′‐(bis(4‐methoxyphenyl)amino)‐[1,1′‐biphenyl]‐4‐yl)fumaronitrile (TPA‐BPFN‐TPA). The new TPA‐BPFN‐TPA with low‐lying HOMO is used as a dopant‐free hole‐transporting material (HTM) in mesoporous perovskite solar cells. The performance of the solar cells using this new HTM is compared with the traditional 2,2′,7,7′‐tetrakis(N,N′‐di‐p‐methoxyphenylamino)‐ 9,9′‐spirobifluorene (Spiro‐OMeTAD) HTM based devices for outdoor and indoor performance evaluation. Under 1 sun illumination, dopant‐free TPA‐BPFN‐TPA HTM based devices exhibit a power conversion efficiency (PCE) of 18.4%, which is the record efficiency to date among D‐A‐D molecular design based dopant‐free HTMs. Moreover, the stability of unencapsulated TPA‐BPFN‐TPA‐based devices shows improvement over Spiro‐OMeTAD‐based devices in harsh relative humidity condition of 70%. Another exciting feature of the newly developed HTM is that the TPA‐BPFN‐TPA‐based devices exhibit improved PCE of 30% and 20.1% at 1000 lux and 200 lux illuminations, respectively. This new finding provides a solution to fabricate low indoor (low light) and outdoor (1 sun) perovskite solar cell devices with high efficiency for cutting‐edge energy harvesting technology.
Designing High‐Performance Storage in HfO2/BiFeO3 Memristor for Artificial Synapse Applications
Authors: Liu Lei , Xiong Wen , Liu Yanxin , Chen Kaige , Xu Zhong , Zhou Yi , Han Jia , Ye Cong , Chen Xin , Song Zhitang , Zhu Min
Published: January 2020

HfO2‐based memristors that remembers the history of the current that has passed through them have attracted great interest for use as artificial synapses in neuromorphic systems. However, the low resistance contrast exhibited by HfO2‐based memristors seriously decreases their recognition accuracy. By inserting a 2 nm BiFeO3 layer a large memory window of 104 and remarkable pulse endurance of 108 cycles are achieved. Multilevel storage capability is also demonstrated by controlling the stop voltages in the RESET process. The conductance–modulation characteristics of a BiFeO3/HfO2 memristor can be used to mimic the learning behaviors of biological synapses, and spiking timing dependent plasticity is mimicked, which is viewed as an important learning rule of biological synapses. Moreover pattern learning and memorization ability like the human brain are achieved by a 3 × 3 memristive device array.
Solution‐Processed, Photo‐Patternable Fluorinated Sol–Gel Hybrid Materials as a Bio‐Fluidic Barrier for Flexible Electronic Systems
Authors: Lee Injun , Kim Yong Ho , Jang Jinhyeong , Lee Kwang‐Heum , Jang Junho , Lim Young‐Woo , Park Sang‐Hee Ko , Park Chan Beum , Lee Wonryung , Bae Byeong‐Soo
Published: January 2020

Reports have recently been published on ultrathin biofluid barriers, which enable the long‐term measurement of biological signals and exhibit conformability on nonlinear surfaces such as skin and organs. However, inorganic‐ and organic‐based barriers have process incompatibility and high water permeability, respectively. Siloxane‐ (inorganic) based fluorinated epoxy (organic) hybrid materials (FEH) are demonstrated for bio‐fluidic barrier and the biocompatibility and barrier performance for flexible electronic systems as solution‐processed oxide thin‐film transistors (TFTs) on 1.2 µm thick polyimide (PI) thin film substrate is confirmed. FEH thin film can be patterned as small as 10 µm through conventional photolithography. The fabricated solution‐processed indium oxide TFTs with FEH barriers exhibit durable performance over 16 h with no dramatic change of transfer characteristics in phosphate‐buffered saline (PBS) environment. Furthermore, to realize FEH barriers for flexible systems, the solution‐processed indium oxide TFTs with FEH barriers on ultrathin PI substrate are demonstrated subjected to compression test and successfully measure the electrical properties with no irreversible degradation during 1000 cycles of mechanical testing in PBS.
Large‐Area Fabrication of High‐Performance Flexible and Wearable Pressure Sensors
Authors: Wu Xiaodong , Khan Yasser , Ting Jonathan , Zhu Juan , Ono Seiya , Zhang Xinxing , Du Shixuan , Evans James W. , Lu Canhui , Arias Ana C.
Published: January 2020

Flexible pressure sensors with high sensitivity, broad working range, and good scalability are highly desired for the next generation of wearable electronic devices. However, manufacturing of such pressure sensors still remains challenging. A large‐area compliant and cost‐effective process to fabricate high‐performance pressure sensors via a combination of mesh‐molded periodic microstructures and printed side‐by‐side electrodes is presented. The sensors exhibit low operating voltage (1 V), high sensitivity (20.9 kPa−1), low detection limit (7.4 Pa), fast response/recovery time (23/18 ms), and excellent reliability (over 10 000 cycles). More importantly, they exhibit ultra‐broad working range (7.4–1 000 000 Pa), high tunability, large‐scale production feasibility, and significant advantage in format miniaturization and creating sensor arrays with self‐defined patterns. The versatility of these devices is demonstrated in various human activity monitoring and spatial pressure mapping as electronic skins. Furthermore, utilizing printing methods, a flexible smart insole with a high level of integration for both foot pressure and temperature mapping is demonstrated. The scalable and cost‐effective manufacturing along with the good comprehensive performance of the pressure sensors makes them very attractive for future development of wearable smart devices and human–machine interfaces.
Long‐Lifetime Triboelectric Nanogenerator Operated in Conjunction Modes and Low Crest Factor
Authors: Li Xinyuan , Yin Xing , Zhao Zhihao , Zhou Linglin , Liu Di , Zhang Chunlei , Zhang Chuguo , Zhang Wei , Li Shaoxin , Wang Jie , Wang Zhong Lin
Published: January 2020

The high‐output triboelectric nanogenerator (TENG) is indispensable for its practical applications toward industrial products. However, the electricity loss in simple parallel connection among all units and the typically high crest factor output seriously hamper the practical applications of TENG. Here, a rectified TENG is reported in parallel structure to solve the problem of electricity loss in simple parallel connection. The rotational contact–separation structure with phase difference between rectified TENGs addresses high crest factor output and extends service life of rotational TENG simultaneously. The current crest factor is dramatically decreased to 1.31 in multiple rectifier multiple TENG in parallel (MRM‐TENG), while that of TENG in simple parallel is higher than 6. Meanwhile, the current output can retain up to ≈93% of its initial performance after 7 200 000 rotations under 2.00 r s−1 of 1000 h. Furthermore, the equivalent current can be in linear growth with low crest factor by making MRM‐TENG in parallel for distributed energy supply without electricity loss. This work may provide a new strategy for TENG in parallel to achieve a low crest factor output and long‐term cycling stability power generation in distributed energy harvesting for large‐scale power application.
What is Killing Organic Photovoltaics: Light‐Induced Crosslinking as a General Degradation Pathway of Organic Conjugated Molecules
Authors: Yamilova Olga R. , Martynov Ilya V. , Brandvold Allison S. , Klimovich Irina V. , Balzer Alex H. , Akkuratov Alexander V. , Kusnetsov Ilya E. , Stingelin Natalie , Troshin Pavel A.
Published: January 2020

In view of a rapid development and increase in efficiency of organic solar cells, reaching their long‐term operational stability represents now one of the main challenges to be addressed on the way toward commercialization of this photovoltaic technology. However, intrinsic degradation pathways occurring in organic solar cells under realistic operational conditions remain poorly understood. The light‐induced dimerization of the fullerene‐based acceptor materials discovered recently is considered to be one of the main causes for burn‐in degradation of organic solar cells. In this work, it is shown that not only the fullerene derivatives but also different types of conjugated polymers and small molecules undergo similar light‐induced crosslinking regardless of their chemical composition and structure. In the case of conjugated polymers, crosslinking of macromolecules leads to a rapid increase in their molecular weight and consequent loss of solubility, which can be revealed in a straightforward way by gel permeation chromatography analysis via a reduction/loss of signal and/or smaller retention times. Results of this work, thus, shift the paradigm of research in the field toward designing a new generation of organic absorbers with enhanced intrinsic photochemical stability in order to reach practically useful operation lifetimes required for successful commercialization of organic photovoltaics.
Soil and crop response to phosphorus and potassium management under conservation tillage
Authors: Yuan Mingwei , Fernández Fabián G. , Pittelkow Cameron M. , Greer Kristin D. , Schaefer Daniel
Published: January 2020

In conservation tillage systems, proper fertilizer phosphorus (P) and potassium (K) management is critical to optimize yield and minimize negative environmental impacts. The objective of this study was to assess the responses of crop yield, nutrient use efficiencies, root growth, and soil test P and K levels to tillage, fertilizer placement, and fertilizer rates in a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation. Experiments were conducted for 8 yr in Illinois with tillage/fertilizer placement as the main plot (no‐till/broadcast [NTBC], strip‐till/broadcast [STBC], and strip‐till/deep band [STDB]) and PK fertilizer rates as the subplot. The NTBC treatment consistently reduced yields in corn by 6.2 and 4.5% and in soybean by 3.1 and 6.1% relative to STBC and STDB, respectively. Also, NTBC had greater root length density at in‐row and between‐row positions relative to STBC and STDB. Nutrient use efficiency indices (partial nutrient balance, agronomic efficiency, and partial factor productivity) declined with increasing P and K rates but were not affected by tillage/fertilizer placement treatments. Deep banding significantly reduced soil P and K concentrations in surface layers while increasing them at the depth of application. These results underscore the reported potential for deep banding combined with strip‐till to improve conditions for nutrient uptake while reducing the risk for nutrient losses to the environment. Critical soil test P and K levels (21 mg P kg−1 and 217 mg K kg−1) were similar for P and greater for K than the current university recommendations, which highlights the need for continuous refinement of soil fertility recommendations to keep pace with changes in production technologies and yield levels.
Light‐Harvesting Nanoparticle Probes for FRET‐Based Detection of Oligonucleotides with Single‐Molecule Sensitivity
Authors: Melnychuk Nina , Egloff Sylvie , Runser Anne , Reisch Andreas , Klymchenko Andrey S.
Published: January 2020

Controlling the emission of bright luminescent nanoparticles by a single molecular recognition event remains a challenge in the design of ultrasensitive probes for biomolecules. Herein, we developed 20‐nm light‐harvesting nanoantenna particles, built of a tailor‐made hydrophobic charged polymer poly(ethyl methacrylate‐co‐methacrylic acid), encapsulating circa 1000 strongly coupled and highly emissive rhodamine dyes with their bulky counterion. Being 87‐fold brighter than quantum dots QDots 605 in single‐particle microscopy (with 550‐nm excitation), these DNA‐functionalized nanoparticles exhibit over 50 % total FRET efficiency to a single hybridized FRET acceptor, a highly photostable dye (ATTO665), leading to circa 250‐fold signal amplification. The obtained FRET nanoprobes enable single‐molecule detection of short DNA and RNA sequences, encoding a cancer marker (survivin), and imaging single hybridization events by an epi‐fluorescence microscope with ultralow excitation irradiance close to that of ambient sunlight.
Tetradentate Gold(III) Complexes as Thermally Activated Delayed Fluorescence (TADF) Emitters: Microwave‐Assisted Synthesis and High‐Performance OLEDs with Long Operational Lifetime
Authors: Zhou Dongling , To Wai‐Pong , Tong Glenna So Ming , Cheng Gang , Du Lili , Phillips David Lee , Che Chi‐Ming
Published: January 2020

Structurally robust tetradentate gold(III)‐emitters have potent material applications but are rare and unprecedented for those displaying thermally activated delayed fluorescence (TADF). Herein, a novel synthetic route leading to the preparation of highly emissive, charge‐neutral tetradentate [C^C^N^C] gold(III) complexes with 5‐5‐6‐membered chelate rings has been developed through microwave‐assisted C−H bond activation. These complexes show high thermal stability and with emission origin (3IL, 3ILCT, and TADF) tuned by varying the substituents of the C^C^N^C ligand. With phenoxazine/diphenylamine substituent, we prepared the first tetradentate gold(III) complexes that are TADF emitters with emission quantum yields of up to 94 % and emission lifetimes of down to 0.62 μs in deoxygenated toluene. These tetradentate AuIII TADF emitters showed good performance in vacuum‐deposited OLEDs with maximum EQEs of up to 25 % and LT95 of up to 5280 h at 100 cd m−2.
A Structurally Characterized Cobalt(I) σ‐Alkane Complex
Authors: Boyd Timothy M. , Tegner Bengt E. , Tizzard Graham J. , Martínez‐Martínez Antonio J. , Neale Samuel E. , Hayward Michael A. , Coles Simon J. , Macgregor Stuart A. , Weller Andrew S.
Published: January 2020

A cobalt σ‐alkane complex, [Co(Cy2P(CH2)4PCy2)(norbornane)][BArF4], was synthesized by a single‐crystal to single‐crystal solid/gas hydrogenation from a norbornadiene precursor, and its structure was determined by X‐ray crystallography. Magnetic data show this complex to be a triplet. Periodic DFT and electronic structure analyses revealed weak C−H→Co σ‐interactions, augmented by dispersive stabilization between the alkane ligand and the anion microenvironment. The calculations are most consistent with a η1:η1‐alkane binding mode.
Diels–Alder Reactions During the Biosynthesis of Sorbicillinoids
Authors: Kahlert Lukas , Bassiony Eman F. , Cox Russell J. , Skellam Elizabeth J.
Published: January 2020

The sorbicillinoids are a class of biologically active and structurally diverse fungal polyketides arising from sorbicillin. Through co‐expression of sorA, sorB, sorC, and sorD from Trichoderma reesei QM6a, the biosynthetic pathway to epoxysorbicillinol and dimeric sorbicillinoids, which resemble Diels–Alder‐like and Michael‐addition‐like products, was reconstituted in Aspergillus oryzae NSAR1. Expression and feeding experiments demonstrated the crucial requirement of the flavin‐dependent monooxygenase SorD for the formation of dimeric sorbicillinoids, hybrid sorbicillinoids, and epoxysorbicillinol in vivo. In contrast to prior reports, SorD catalyses neither the oxidation of 2′,3′‐dihydrosorbicillin to sorbicillin nor the oxidation of sorbicillinol to oxosorbicillinol. This is the first report that both the intermolecular Diels–Alder and Michael dimerization reactions, as well as the epoxidation of sorbicillinol are catalysed in vivo by SorD.
Designing a 0D/2D S‐Scheme Heterojunction over Polymeric Carbon Nitride for Visible‐Light Photocatalytic Inactivation of Bacteria
Authors: Xia Pengfei , Cao Shaowen , Zhu Bicheng , Liu Mingjin , Shi Miusi , Yu Jiaguo , Zhang Yufeng
Published: January 2020

Constructing heterojunctions between two semiconductors with matched band structure is an effective strategy to acquire high‐efficiency photocatalysts. The S‐scheme heterojunction system has shown great potential in facilitating separation and transfer of photogenerated carriers, as well as acquiring strong photoredox ability. Herein, a 0D/2D S‐Scheme heterojunction material involving CeO2quantum dots and polymeric carbon nitride (CeO2/PCN) is designed and constructed by in situ wet chemistry with subsequent heat treatment. This S‐scheme heterojunction material shows high‐efficiency photocatalytic sterilization rate (88.1 %) towards Staphylococcus aureus (S. aureus) under visible‐light irradiation (λ≥420 nm), which is 2.7 and 8.2 times that of pure CeO2(32.2 %) and PCN (10.7 %), respectively. Strong evidence of S‐scheme charge transfer path is verified by theoretical calculations, in situ irradiated X‐ray photoelectron spectroscopy, and electron paramagnetic resonance.
Embedding Ultrasmall Au Clusters into the Pores of a Covalent Organic Framework for Enhanced Photostability and Photocatalytic Performance
Authors: Deng Yang , Zhang Zhen , Du Peiyao , Ning Xingming , Wang Yue , Zhang Dongxu , Liu Jia , Zhang Shouting , Lu Xiaoquan
Published: January 2020

Gold clusters loaded on various supports have been widely used in the fields of energy and biology. However, the poor photostability of Au clusters on support interfaces under prolonged illumination usually results in loss of catalytic performance. Covalent organic frameworks (COFs) with periodic and ultrasmall pore structures are ideal supports for dispersing and stabilizing Au clusters, although it is difficult to encapsulate Au clusters in the ultrasmall pores. In this study, a two‐dimensional (2D) COF modified with thiol chains in its pores was prepared. With −SH groups as nucleation sites, Au nanoclusters (NCs) could grow in situ within the COF. The ultrasmall pores of the COF and the strong S−Au binding energy combine to improve the dispersibility of Au NCs under prolonged light illumination. Interestingly, Au–S–COF bridging as observed in this artificial Z‐scheme photocatalytic system is deemed to be an ideal means to increase charge‐separation efficiency.
Multicomponent Peptide Stapling as a Diversity‐Driven Tool for the Development of Inhibitors of Protein–Protein Interactions
Authors: Ricardo Manuel G. , Ali Ameena M. , Plewka Jacek , Surmiak Ewa , Labuzek Beata , Neochoritis Constantinos G. , Atmaj Jack , Skalniak Lukasz , Zhang Ran , Holak Tad A. , Groves Matthew , Rivera Daniel G. , Dömling Alexander
Published: January 2020

Stapled peptides are chemical entities in‐between biologics and small molecules, which have proven to be the solution to high affinity protein–protein interaction antagonism, while keeping control over pharmacological performance such as stability and membrane penetration. We demonstrate that the multicomponent reaction‐based stapling is an effective strategy for the development of α‐helical peptides with highly potent dual antagonistic action of MDM2 and MDMX binding p53. Such a potent inhibitory activity of p53‐MDM2/X interactions was assessed by fluorescence polarization, microscale thermophoresis, and 2D NMR, while several cocrystal structures with MDM2 were obtained. This MCR stapling protocol proved efficient and versatile in terms of diversity generation at the staple, as evidenced by the incorporation of both exo‐ and endo‐cyclic hydrophobic moieties at the side chain cross‐linkers. The interaction of the Ugi‐staple fragments with the target protein was demonstrated by crystallography.
Achieving Efficient Multichannel Conductance in Through‐Space Conjugated Single‐Molecule Parallel Circuits
Authors: Shen Pingchuan , Huang Miaoling , Qian Jingyu , Li Jinshi , Ding Siyang , Zhou Xiao‐Shun , Xu Bin , Zhao Zujin , Tang Ben Zhong
Published: January 2020

Constructing single‐molecule parallel circuits with multiple conduction channels is an effective strategy to improve the conductance of a single molecular junction, but rarely reported. We present a novel through‐space conjugated single‐molecule parallel circuit (f‐4Ph‐4SMe) comprised of a pair of closely parallelly aligned p‐quaterphenyl chains tethered by a vinyl bridge and end‐capped with four SMe anchoring groups. Scanning‐tunneling‐microscopy‐based break junction (STM‐BJ) and transmission calculations demonstrate that f‐4Ph‐4SMe holds multiple conductance states owing to different contact configurations. When four SMe groups are in contact with two electrodes at the same time, the through‐bond and through‐space conduction channels work synergistically, resulting in a conductance much larger than those of analogous molecules with two SMe groups or the sum of two p‐quaterphenyl chains. The system is an ideal model for understanding electron transport through parallel π‐stacked molecular systems and may serve as a key component for integrated molecular circuits with controllable conductance.
Rational Development of Remote C−H Functionalization of Biphenyl: Experimental and Computational Studies
Authors: Fan Zhoulong , Bay Katherine L. , Chen Xiangyang , Zhuang Zhe , Park Han Seul , Yeung Kap‐Sun , Houk K. N. , Yu Jin‐Quan
Published: January 2020

A simple and efficient nitrile‐directed meta‐C−H olefination, acetoxylation, and iodination of biaryl compounds is reported. Compared to the previous approach of installing a complex U‐shaped template to achieve a molecular U‐turn and assemble the large‐sized cyclophane transition state for the remote C−H activation, a synthetically useful phenyl nitrile functional group could also direct remote meta‐C−H activation. This reaction provides a useful method for the modification of biaryl compounds because the nitrile group can be readily converted to amines, acids, amides, or other heterocycles. Notably, the remote meta‐selectivity of biphenylnitriles could not be expected from previous results with a macrocyclophane nitrile template. DFT computational studies show that a ligand‐containing Pd–Ag heterodimeric transition state (TS) favors the desired remote meta‐selectivity. Control experiments demonstrate the directing effect of the nitrile group and exclude the possibility of non‐directed meta‐C−H activation. Substituted 2‐pyridone ligands were found to be key in assisting the cleavage of the meta‐C−H bond in the concerted metalation–deprotonation (CMD) process.
Selective and Sensitive Two New Macroacyclic Schiff base Fluorescent Turn‐Off Receptors for Fe3+, DFT Calculation and Their Antibacterial Activity
Authors: Ooshall Farkhondeh , Golbedaghi Reza , Jamehbozorgi Saeed
Published: January 2020

Two new Macroacyclic Schiff base chemosensors (L1 and L2) were synthesized by the one pot condensation reaction of 2‐[3‐(2‐formyl phenoxy)propoxy]benzaldehyde and aminophenol in a 1:2 molar ratio and were characterized by IR, NMR spectroscopy. Both Schiff bases displayed high selectivity and sensitivity towards Fe3+ over other metal ions in H2O‐DMF solution (Ag+,Cu2+, Ni2+, Zn2+, Mg+2, Mn+2, Pb+2, Co+2, Hg+2, Cr+3, Na+, Ba+2 and Cd2+) due to their structure including oxygen donor atoms. The test results showed fluorescence quenching of the fluorophores when Fe3+ was bound to the recognition units. From test results, a high selectivity for Fe3+ were discovered in this type of sensors, especially, the probe based on 2‐aminophenol exhibited more significant quenching in fluorescence intensity compared with 4‐aminophenol‐based due to its rigidity structure. In addition, the structure of ligands and their antibacterial properties was investigated.
A novel composite derived from a metal organic framework immobilized within electrospun nanofibrous polymers: An efficient methane adsorbent
Authors: Sargazi Ghasem , Afzali Daryoush , Mostafavi Ali , Kazemian Hossein
Published: January 2020

In this study, tantalum(V) metal organic framework (Ta‐MOF) nanostructure was incorporated within polyvinyl alcohol (PVA) nanofibers to prepare an electrospun porous composite as a novel CH4 adsorbent. The crystallinity, thermodynamic behavior, and textural properties of the products were investigated using instrumental analyses techniques. The results confirmed that the developed PVA/Ta‐MOF electrospun nanofibrous composite exhibits higher thermal stability, considerable porosity, and larger surface area compared to the parent Ta‐MOF. A 2k factorial design was used for systematic study of the adsorption process. The results of response surface methodology (RSM) optimization indicated that the highest methane adsorption can be achieved at 24.40 °C and 3.70 bar in 23.60 min. These nano pore sorbents showed a significant potential for CH4 adsorption due to the presence of Ta‐MOF at the surface of nanofibrous composite compared to many other conventional sorbents that have been already used. This study introduces a novel biocompatible/biodegradable nanofibrous composite material with high methane adsorption performance and potentials for other applications.
Desulfurization of model and real fuels by extraction and oxidation processes using an indenylmolybdenum tricarbonyl pre‐catalyst
Authors: Julião Diana , Gomes Ana C. , Pillinger Martyn , Valença Rita , Ribeiro Jorge C. , Gonçalves Isabel S. , Balula Salete S.
Published: January 2020

Regulations on the permissible levels of sulfur in transportation fuels are becoming ever more strict, with a global shift towards “zero sulfur” fuels, and the revamp of existing hydrodesulfurization (HDS) facilities to meet these lower caps is cost‐prohibitive. Metal‐catalyzed sulfoxidation chemistry is viewed as an economically viable desulfurization strategy that could complement conventional HDS technology. In the present work, the complex [η5‐IndMo(CO)3Me] (1) (Ind = indenyl) was employed in the catalytic oxidative desulfurization (CODS) of model and real liquid fuels, using aqueous hydrogen peroxide (H2O2) as oxidant. After optimization of the CODS reaction parameters (diesel/H2O2 ratio, catalyst amount, temperature), a high‐sulfur (2000 ppm) model diesel containing benzothiophene, dibenzothiophene, 4‐methyldibenzothiophene and 4,6‐dimethyldibenzothiophene could be completely desulfurized within 2 hr under solvent‐free conditions or in the presence of the ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([BMIM]PF6) as extraction solvent. The catalyst formed under solvent‐free conditions could be recycled without a significant decrease in desulfurization activity. The high performance of the CODS system was verified in the sulfur removal from a commercial untreated diesel fuel with a sulfur content of 2300 ppm, and a jet fuel with a sulfur content of 1100 ppm. Solvent‐free CODS in combination with initial/final extraction gave desulfurization efficiencies of 70% for the diesel fuel and 55% for the jet fuel. CODS with [BMIM]PF6 in combination with initial/final extraction led to a sulfur removal of 95.9% for the diesel fuel, which is one of the best results yet reported for ODS of commercial diesels.
Ion transfer modeling based on Nernst–Planck theory for saline water desalination during electrodialysis process
Authors: Zhu Haitao , Yang Bo , Gao Congjie , Wu Yaqin
Published: January 2020

Electrodialysis, an efficient and environmental friendly separation technology, plays a significant role in water treatment. In order to reveal ion transfer mechanism and predict electrodialysis behavior, a mathematical model for steady transport of a binary electrolyte during the desalination process was developed. The Nernst–Planck, electroneutrality equations, and other hydrodynamic equations were coupled and solved with appropriate boundary conditions using the finite element method. This model is capable to predict the local ion concentration, electric potential, and ion flux in a rectangular electrodialysis unit. The effects of voltage drop (0.4–1.0 V), inlet velocity (0.03–0.06 m/s), and initial feed concentration (500–700 mol/m3) are investigated, which could provide valuable guidance for electrodialysis operation in the practical project. Moreover, this model is validated by comparing its simulation result with experimental data of electrodialysis, and it could predict the desalination of saline water accurately. Ion transfer modeling provides an effective way to study the transfer mechanism, estimate the effects of various parameters conveniently, and realize the target‐oriented operation optimization.
A new microraptorine theropod from the Jehol Biota and growth in early dromaeosaurids
Authors: Poust Ashley W. , Gao Chunling , Varricchio David J. , Wu Jianlin , Zhang Fengjiao
Published: January 2020

Fossils from the Jehol Group (Early Cretaceous, Liaoning Province, China) are integral to our understanding of Paraves, the clade of dinosaurs grouping dromaeosaurids, troodontids, and avialians, including living birds. However, many taxa are represented by specimens of unclear ontogenetic age. Without a more thorough understanding of ontogeny, evolutionary relationships and significance of character states within paravian dinosaurs may be obscured and our ability to infer their biology restricted. We describe a complete specimen of a new microraptorine dromaeosaur, Wulong bohaiensis gen. et sp. nov., from the geologically young Jiufotang Formation (Aptian) that helps solve this problem. Phylogenetic analysis recovers the specimen within a monophyletic Microraptorinae. Preserved in articulation on a single slab, the type specimen is small and exhibits osteological markers of immaturity identified in other archosaurs, such as bone texture and lack of fusion. To contextualize this signal, we histologically sampled the tibia, fibula, and humerus and compared them with new samples from the closely related and osteologically mature Sinornithosaurus. Histology shows both specimens to be young and still growing at death, indicating an age for the new dinosaur of about 1 year. The holotype possesses several feather types, including filamentous feathers, pennaceous primaries, and long rectrices, establishing that their growth preceded skeletal maturity and full adult size in some dromaeosaurids. Comparison of histology in the new taxon and Sinornithosaurus indicates that macroscopic signs of maturity developed after the first year, but before cessation of growth, demonstrating that nonhistological indicators of adulthood may be misleading when applied to dromaeosaurids. Anat Rec, 303:963–987, 2020. © 2020 American Association for Anatomy
A Data‐Based Guide to the North American Ecology Faculty Job Market
Authors: Fox Jeremy
Published: January 2020

Every year for three years (2016–2018), I tried to identify every single person hired as a tenure‐track professor in ecology or an allied field (e.g., fish and wildlife) in the United States and Canada by consulting public sources. I identified a total of 566 hires. I also used public sources to compile data on the new hires and the institutions that hired them (e.g., number of publications, teaching experience, hiring institution Carnegie class). These data address some widespread anxieties and misunderstandings about the ecology faculty job market and also speak to gender diversity in recent ecology faculty hiring. They complement, and in some cases improve on, other sources of information, such as anecdotal personal experiences.
Plasmonic Biosensor Controlled by DNAzyme for On‐Site Genetic Detection of Pathogens
Authors: Lee Woogi , Hwang Byeong Hee
Published: January 2020

On‐site predetection of pathogens could significantly decrease of a disease outbreak or national loss in most of the countries. However, conventional detection techniques are limited in use for on‐site detection due to the necessity of specialized skill or equipment. Therefore, it is necessary to develop a new technique that can predetect pathogens in the field without special skills or equipment. Here, a DNAzyme strategy to control a plasmonic biosensor for rapid and simple visual detection of Salmonella choleraesuis is adopted. Multicomponent DNAzyme formed by target addition can cleave the linker effectively at 50 °C. Linker cleavage induces dispersion of two DNA‐immobilized gold nanoparticles and color change. Under optimized assay conditions, the target could be detected via visual discrimination sensitively and specifically. Moreover, the biosensor shows the possibility of practical use with contaminants and a 16S rRNA real target. As a result, the proposed plasmonic biosensor can visually detect S. choleraesuis without unstable enzymes, a specialized technique, or equipment. Therefore, these advantages could allow that this biosensor would be used for on‐site predetection to lower the risk of transmission of infectious diseases.
Analysis of variations in the contents of steroidal saponins in Fructus Tribuli during stir‐frying treatment
Authors: Zhang Chao , Wang Shuyue , Guo Fei , Ma Ting , Zhang Longfei , Sun Linlin , Wang Yingzi , Zhang Xuelan
Published: January 2020

Just as natural saponins transform into aglycones, secondary glycosides and their derivatives using biotransformation technology, steroidal saponins may also undergo similar transformation after stir‐frying. The purpose of this study was to elucidate the variations and the reasons for these variations in the contents of steroidal saponins in Fructus Tribuli (FT) during a stir‐frying treatment. Stir‐fried FT was processed in different time–temperature conditions. An UHPLC–MS/MS method was established and fully validated for quantitative analysis. In addition, the simulation processing products of tribuluside A, terrestroside B, terrestrosin K, terrestrosin D and 25R‐tribulosin were determined by qualitative analysis using UHPLC–Q‐TOF–MS. The established UHPLC–MS/MS method provides a rapid, flexible, and reliable method for the quality assessment of FT. The present study revealed that furostanol saponins with a C22‐OH group could transform into corresponding furostanol saponins with a C‐20–C‐22 double bond (FSDB) via dehydroxylation. Additionally, FSDB could be successively converted into its secondary glycosides via a deglycosylation reaction. The transformation of spirostanol saponins into corresponding aglycones via deglycosylation led to a decrease in spirostanol saponins and an increase in aglycones. The results of this research provided scientific evidence of variation and structural transformation among steroidal saponins. These findings might be helpful for elucidating the processing mechanism of FT.