bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rare‐Earth‐Element‐Ytterbium‐Substituted Lead‐Free Inorganic Perovskite Nanocrystals for Optoelectronic Applications
Authors: Moon Byung Joon , Kim Sang Jin , Lee Seungmin , Lee Aram , Lee Hyunjung , Lee Dong Su , Kim Tae‐Wook , Lee Seoung‐Ki , Bae Sukang , Lee Sang Hyun 
Published: June 2019

AbstractLead‐(Pb‐) halide perovskite nanocrystals (NCs) are interesting nanomaterials due to their excellent optical properties, such as narrow‐band emission, high photoluminescence (PL) efficiency, and wide color gamut. However, these NCs have several critical problems, such as the high toxicity of Pb, its tendency to accumulate in the human body, and phase instability. Although Pb‐free metal (Bi, Sn, etc.) halide perovskite NCs have recently been reported as possible alternatives, they exhibit poor optical and electrical properties as well as abundant intrinsic defect sites. For the first time, the synthesis and optical characterization of cesium ytterbium triiodide (CsYbI3) cubic perovskite NCs with highly uniform size distribution and high crystallinity using a simple hot‐injection method are reported. Strong excitation‐independent emission and high quantum yields for the prepared NCs are verified using photoluminescence measurements. Furthermore, these CsYbI3 NCs exhibit potential for use in organic–inorganic hybrid photodetectors as a photoactive layer. The as‐prepared samples exhibit clear on–off switching behavior as well as high photoresponsivity (2.4 × 103 A W−1) and external quantum efficiency (EQE, 5.8 × 105%) due to effective exciton dissociation and charge transport. These results suggest that CsYbI3 NCs offer tremendous opportunities in electronic and optoelectronic applications, such as chemical sensors, light emitting diodes (LEDs), and energy conversion and storage devices.
Fabrication of High‐Performance Silver Mesh for Transparent Glass Heaters via Electric‐Field‐Driven Microscale 3D Printing and UV‐Assisted Microtransfer
Authors: Zhu Xiaoyang , Xu Quan , Li Hongke , Liu Mingyang , Li Zhenghao , Yang Kun , Zhao Jiawei , Qian Lei , Peng Zilong , Zhang Guangming , Yang Jianjun , Wang Fei , Li Dichen , Lan Hongbo 
Published: June 2019

AbstractGreat challenges remain concerning the cost‐effective manufacture of high‐performance metal meshes for transparent glass heaters (TGHs). Here, a high‐performance silver mesh fabrication technique is proposed for TGHs using electric‐field‐driven microscale 3D printing and a UV‐assisted microtransfer process. The results show a more optimal trade‐off in sheet resistance (Rs = 0.21 Ω sq−1) and transmittance (T = 93.9%) than for indium tin oxide (ITO) and ITO substitutes. The fabricated representative TGH also exhibits homogeneous and stable heating performance, remarkable environmental adaptability (constant Rs for 90 days), superior mechanical robustness (Rs increase of only 0.04 in harsh conditions–sonication at 100 °C), and strong adhesion force with a negligible increase in Rs (2–12%) after 100 peeling tests. The practical viability of this TGH is successfully demonstrated with a deicing test (ice cube: 21 cm3, melting time: 78 s, voltage and glass thickness: 4 V, 5 mm). All of these advantages of the TGHs are attributed to the successful fabrication of silver meshes with high resolution and high aspect ratio on the glass substrate using the thick film silver paste. The proposed technique is a promising new tool for the inexpensive fabrication of high‐performance TGHs.
Recent Trends in the Silver‐Catalyzed Synthesis of Nitrogen Heterocycles
Authors: Sreedevi Radhakrishnan , Saranya Salim , Anilkumar Gopinathan 
Published: June 2019

AbstractHeterocycles are generally biologically active compounds and are the main basic scaffolds in many natural and non‐natural moieties. Recently, silver‐catalyzed syntheses have undergone remarkable progress in the field of synthetic heterocyclic chemistry. This review summarizes the recent trends in the silver‐catalyzed synthesis of nitrogen‐containing heterocyclic compounds.magnified image
14.1% CsPbI3 Perovskite Quantum Dot Solar Cells via Cesium Cation Passivation
Authors: Ling Xufeng , Zhou Sijie , Yuan Jianyu , Shi Junwei , Qian Yuli , Larson Bryon W. , Zhao Qian , Qin Chaochao , Li Fangchao , Shi Guozheng , Stewart Connor , Hu Jiaxin , Zhang Xuliang , Luther Joseph M. , Duhm Steffen , Ma Wanli 
Published: June 2019

AbstractSurface manipulation of quantum dots (QDs) has been extensively reported to be crucial to their performance when applied into optoelectronic devices, especially for photovoltaic devices. In this work, an efficient surface passivation method for emerging CsPbI3 perovskite QDs using a variety of inorganic cesium salts (cesium acetate (CsAc), cesium idodide (CsI), cesium carbonate (Cs2CO3), and cesium nitrate (CsNO3)) is reported. The Cs‐salts post‐treatment can not only fill the vacancy at the CsPbI3 perovskite surface but also improve electron coupling between CsPbI3 QDs. As a result, the free carrier lifetime, diffusion length, and mobility of QD film are simultaneously improved, which are beneficial for fabricating high‐quality conductive QD films for efficient solar cell devices. After optimizing the post‐treatment process, the short‐circuit current density and fill factor are significantly enhanced, delivering an impressive efficiency of 14.10% for CsPbI3 QD solar cells. In addition, the Cs‐salt‐treated CsPbI3 QD devices exhibit improved stability against moisture due to the improved surface environment of these QDs. These findings will provide insight into the design of high‐performance and low‐trap‐states perovskite QD films with desirable optoelectronic properties.
Lithiophilic CuO Nanoflowers on Ti‐Mesh Inducing Lithium Lateral Plating Enabling Stable Lithium‐Metal Anodes with Ultrahigh Rates and Ultralong Cycle Life
Authors: Huang Kai , Li Zhi , Xu Qunjie , Liu Haimei , Li Hexing , Wang Yonggang 
Published: June 2019

AbstractLithium (Li) metal anodes are promising candidates for high‐energy‐density batteries. However, uncontrollable dendritic plating behavior and infinite volume expansion are hindering their practical applications. Herein, a novel CuO@Ti‐mesh (CTM) is prepared by microwave‐assisted reactions, followed by pressing on Li wafers, leading to Li/CuO@Ti‐mesh (LCTM) composite anodes. The lithiophilic CuO nanoflowers on Ti‐mesh provides evenly distributed nucleation sites, inducing uniform Li‐ion lateral plating, which can effectively inhibit the growth of Li dendrites and volume expansion during cycling. The as‐prepared LCTM composite anode exhibits high Coulombic efficiency (CE) of 94.2% at 10 mA cm‐2 over 90 cycles. Meanwhile, the LCTM anode shows a low overpotential of 50 mV at 10 mA cm‐2 over 16 000 cycles and a low overpotential of 90 and 250 mV even at ultrahigh current densities of 20 and 40 mA cm‐2. When paired with Li4Ti5O12 (LTO), it enhances the capacity retention of LTO/Li wafer full cells by about two times from 36.6% to 73.0% and 42.0% to 80.0% at 5C and 10C with long‐term cycling. It is hoped that this LCTM anode with ultrahigh rates and ultralong cycle life may put Li‐metal anode forward to practical applications, such as in Li–S, Li‐air batteries, etc.
A High‐Performance Monolithic Solid‐State Sodium Battery with Ca2+ Doped Na3Zr2Si2PO12 Electrolyte
Authors: Lu Yao , Alonso Jose A. , Yi Qiang , Lu Liang , Wang Zhong Lin , Sun Chunwen 
Published: June 2019

AbstractSolid‐state sodium batteries (SSSBs) are promising electrochemical energy storage devices due to their high energy density, high safety, and abundant resource of sodium. However, low conductivity of solid electrolyte as well as high interfacial resistance between electrolyte and electrodes are two main challenges for practical application. To address these issues, pure phase Na3Zr2Si2PO12 (NZSP) materials with Ca2+ substitution for Zr4+ are synthesized by a sol‐gel method. It shows a high ionic conductivity of more than 10−3 S cm−1 at 25 °C. Moreover, a robust SSSB is developed by integrating sodium metal anodes into NZSP‐type monolithic architecture, forming a 3D electronic and ionic conducting network. The interfacial resistance is remarkably reduced and the monolithic symmetric cell displays stable sodium platting/striping cycles with low polarization for over 600 h. Furthermore, by combining sodium metal anode with Na3V2(PO4)3 cathode, an SSSB is demonstrated with high rate capability and excellent cyclability. After 450 cycles, the capacity of the cell is still kept at 94.9 mAh g−1 at 1 C. This unique design of monolithic electrolyte architecture provides a promising strategy toward realizing high‐performance SSSBs.
A Fully Reversible Water Electrolyzer Cell Made Up from FeCoNi (Oxy)hydroxide Atomic Layers
Authors: Zhang Qingran , Bedford Nicholas M. , Pan Jian , Lu Xunyu , Amal Rose 
Published: June 2019

AbstractRenewable electricity powered water electrolysis is a promising solution for the conversion and storage of the intermittent renewable energy resources in the form of hydrogen. Herein, atomically thin FeCoNi ternary (oxy)hydroxide nanosheets (FeCoNi‐ATNs) are developed as efficient and robust bifunctional electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in 1 m KOH solution (pH = 14). The electrocatalyst shows remarkably high apparent catalytic performance (400 mA cm−2 at 350 mV for OER and 240 mV for HER) and mass activities at modest overpotentials (1931 A g−1 at 330 mV for OER; 1819 A g−1 at 200 mV for HER). Moreover, the OER and HER performance of FeCoNi–ATNs are fully reversible and electrochemically switchable, due to the interconversion attribute of two catalytic states for OER and HER. Using the dual functional properties of this catalyst, a fully reversible water electrolyzer cell is fabricated, exhibiting a robust reversibility between two half reactions in water electrolysis under a high current density (100 mA cm−1), which can effectively overcome the stability issues caused by electrode depolarization during frequent power interruptions, an inevitable phenomenon commonly brought about by the usage of intermittent renewable energy supplies.
Realizing High‐Ranged Out‐of‐Plane ZTs in N‐Type SnSe Crystals through Promoting Continuous Phase Transition
Authors: Chang Cheng , Wang Dongyang , He Dongsheng , He Wenke , Zhu Fangyuan , Wang Guangtao , He Jiaqing , Zhao Li‐Dong 
Published: June 2019

AbstractThermoelectric technology enables direct conversion between heat and electricity. The conversion efficiency of a thermoelectric device is determined by the average dimensionless figure of merit ZTave. Here, a record high ZTave of ≈1.34 in the range of 300–723 K in n‐type SnSe based crystals is reported. The remarkable thermoelectric performance derives from the high power factor and the reduced thermal conductivity in the whole temperature range. The high power factor is realized by promoting the continuous phase transition in SnSe crystals through alloying PbSe, which results in a higher symmetry of the crystal structure and the correspondingly modified electronic band structure. Moreover, PbSe alloying induces mass and strain fluctuations, which enables the suppression of thermal transport. These findings provide a new strategy to enhance the thermoelectric performance for the continuous phase transition materials.
In vitro Reconstitution of the Biosynthetic Pathway to the Nitroimidazole Antibiotic Azomycin
Authors: Hedges Jason B. , Ryan Katherine S. 
Published: June 2019

AbstractNitroimidazoles are one of the most effective ways to treat anaerobic bacterial infections. Synthetic nitroimidazoles are inspired by the structure of azomycin, isolated from Streptomyces eurocidicus in 1953. Despite its foundational role, no biosynthetic gene cluster for azomycin has been found. Guided by bioinformatics, we identified a cryptic biosynthetic gene cluster in Streptomyces cattleya and then carried out in vitro reconstitution to deduce the enzymatic steps in the pathway linking l‐arginine to azomycin. The gene cluster we discovered is widely distributed among soil‐dwelling actinobacteria and proteobacteria, suggesting that azomycin and related nitroimidazoles may play important ecological roles. Our work sets the stage for development of biocatalytic approaches to generate azomycin and related nitroimidazoles.
Polybenzimidazole as proton conducting filler in polydimethylsiloxane: Enhanced oxidative stability and membrane properties
Authors: Satheesh Kumar B. , Sana Balakondareddy , Unnikrishnan G. , Jana Tushar , Santhosh Kumar K. S. 
Published: June 2019

ABSTRACTIn this work, pyridine‐based low‐molecular‐weight polybenzimidazole (LMP) was synthesized (inherent viscosity: 0.52 dL g−1) by controlling the reaction time. The synthesized LMP was incorporated into polydimethylsiloxane (PDMS) matrix to impart proton conductivity. The composite membrane containing 30 wt % of LMP exhibited proton conductivity of 16 mS cm−1 at 100–120 °C. The LMP chains were bundled and formed clusters (aggregates) in the PDMS matrix as observed in field emission scanning electron microscopy. This is attributed to nonpolar (siloxane)–polar (polybenzimidazole) repulsion. An impressive weight loss of 8.6% was observed after 120 h Fenton's test that indicates the high oxidative stability of composite membranes. However, elongation of composite membranes was decreased compared to that of pristine PDMS, which is attributed to the incorporation of rigid LMP chains. The resultant composite membranes exhibited moderate proton conductivity, low moisture absorption, and good thermal stability. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48151.
Preparation of regenerated silk fibroin‐based heat‐management sponge for wound healing
Authors: Li Yu , Zhao Liang , Wang Hao , Li Baohua 
Published: June 2019

ABSTRACTIn the present study, a regenerated silk fibroin (RSF) sponge incorporated with the phase change microcapsules were synthesized by facile and effective routes. The microcapsules with the phase change materials (PCMs) core and the RSF wall were prepared by simple coacervation. By altering the synthesis parameters including the emulsifier concentration and the RSF concentration, the microcapsules exhibiting optimized spherical geometry, high encapsulation efficiency, high phase change enthalpies, good thermal cycling performance, and high thermal stability were synthesized. As to the preparation of the microstructurally aligned RSF sponge, a new type of freeze–thaw method was used for the first time, the resultant sponge exhibited high elastic resilience. Subsequently, the combination of microcapsules with the RSF sponge was achieved by a convenient deposition method with the aid of ultrasonic agitation, which showed well maintained porous structure and satisfactory phase change enthalpies of 23.16 and 23.32 J•g−1 corresponding to the heating and cooling process, respectively. Therefore, the PCMs‐incorporated RSF sponge exhibited the capacity to regulate the temperature in order to create a stable “microclimate.” Regarding the exceptional biocompatibility, biodegradability, and super comfort of RSF materials, the RSF‐based sponge can be an ideal candidate for wound dressing applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48173.
A machine‐learning approach to calibrate generic Raman models for real‐time monitoring of cell culture processes
Authors: Tulsyan Aditya , Schorner Gregg , Khodabandehlou Hamid , Wang Tony , Coufal Myra , Undey Cenk 
Published: June 2019

AbstractThe manufacture of biotherapeutic proteins consists of complex upstream unit operations requiring multiple raw materials, analytical techniques, and control strategies to produce safe and consistent products for patients. Raman spectroscopy is a ubiquitous multipurpose analytical technique in biopharmaceutical manufacturing for real‐time predictions of critical parameters in cell culture processes. The accuracy of Raman spectroscopy relies on chemometric models that need to be carefully calibrated. The existing calibration procedure is nontrivial to implement as it necessitates executing multiple carefully designed experiments for generating relevant calibration sets. Further, existing procedure yields calibration models that are reliable only in operating conditions they were calibrated in. This creates a unique challenge in clinical manufacturing where products have limited production history. In this paper, a novel machine‐learning procedure based on just‐in‐time learning (JITL) is proposed to calibrate Raman models. Unlike traditional techniques, JITL‐based generic Raman models can be reliably used for different modalities, cell lines, culture media, and operating conditions. The accuracy of JITL‐based generic models is demonstrated on several validation studies involving real‐time predictions of critical cell culture performance parameters, such as glucose, glutamate, glutamine, ammonium, lactate, sodium, calcium, viability, and viable cell density. The proposed JITL framework introduces a paradigm shift in the way industrial Raman models are calibrated, which to the best of authors’ knowledge have not been done before.
Synthesis of β‐Chiral Amines by Dynamic Kinetic Resolution of α‐Branched Aldehydes Applying Imine Reductases
Authors: Matzel Philipp , Wenske Sebastian , Merdivan Simon , Günther Sebastian , Höhne Matthias 
Published: June 2019

AbstractImine reductases (IREDs) allow the one‐step preparation of optically active secondary and tertiary amines by reductive amination of ketones. Until now, mainly α‐chiral amines have been prepared by this route. In this study, we explored the possibility of synthesizing β‐chiral amines, a class of compounds which is also frequently found as structural motif in pharmaceuticals but much more challenging to prepare due to the following reasons: (i) The aldehyde substrate already contains the chiral center and needs to be racemized to enable full conversion. (ii) Because the intermediate imine bears the stereo center two carbon atoms remote to the imine nitrogen, it is more challenging to achieve high enantioselectivity compared to α‐chiral amine synthesis. For investigating the proof of concept, we first confirmed that different IREDs are able to convert a variety of α‐branched aldehydes when combined with five different amine substrates. The IRED from Streptomyces ipomoeae was a suitable enzyme facilitating the dynamic kinetic resolution of 2‐phenylpropanal and a substituted 2‐methyl‐3‐phenylpropanal: the corresponding N‐methylated β‐chiral amines were obtained with >95 % conversion and 78 and 95 %ee. Other amines were formed with low to moderate enantiomeric excess. This exemplifies the potential of IREDs for the one‐step synthesis of secondary β‐chiral amines, but also the challenge to identify highly selective enzymes for a desired amine product.
Electrocatalytic H2 Evolution by the Co‐Mabiq Complex Requires Tempering of the Redox‐Active Ligand
Authors: Tok G. Ceren , Freiberg Anna T. S. , Gasteiger Hubert A. , Hess Corinna R. 
Published: June 2019

AbstractH2 is a promising fuel for sustainable energy conversion and storage. The development of effective earth abundant H2 evolution catalysts is integral to advancing hydrogen‐based technologies. H2 evolution by molecular complexes classically involves the formation of metal hydride intermediates. Recently, the use of redox‐active ligands has emerged as an alternate strategy for electron and proton storage. Herein, we examine the electrocatalytic behavior of [CoII(Mabiq)(THF)](PF6) (CoMbq), containing a redox‐active macrocyclic ligand, in acidic, organic media (using para‐cyanoanilinium (pCA) as the proton source). Cyclic voltammetry (CV) and Rotating Ring Disk Electrode (RRDE) voltammetry evidence a pre‐catalytic process that leads to the formation of a protonated, two‐electron reduced intermediate. This species evolves H2 at potentials negative of −1.1 VFc, as confirmed by On‐line Electrochemical Mass Spectrometry (OEMS). OEMS results further reveal a catalyst deactivation pathway. The electrochemical data denote the involvement of the redox‐active Mabiq ligand in the hydrogen evolution reaction (HER), with implications for the use of such scaffolds in electrocatalytic complexes.
KRAS Binders Hidden in Nature
Authors: Bergner Andreas , Cockcroft Xiaoling , Fischer Gerhard , Gollner Andreas , Hela Wolfgang , Kousek Roland , Mantoulidis Andreas , Martin Laetitia J. , Mayer Moriz , Müllauer Barbara , Siszler Gabriella , Wolkerstorfer Bernhard , Kessler Dirk , McConnell Darryl B. 
Published: June 2019

AbstractNatural products have proven to be a rich source of molecular architectures for drugs. Here, an integrated approach to natural product screening is proposed, which uncovered eight new natural product scaffolds for KRAS—the most frequently mutated oncogenic driver in human cancers, which has remained thus far undrugged. The approach combines aspects of virtual screening, fragment‐based screening, structure‐activity relationships (SAR) by NMR, and structure‐based drug discovery to overcome the limitations in traditional natural product approaches. By using our approach, a new “snugness of fit” scoring function and the first crystal‐soaking system of the active form of KRASG12D, the protein–ligand X‐ray structures of a tricyclic indolopyrrole fungal alkaloid and an indoloisoquinolinone have been successfully elucidated. The natural product KRAS hits discovered provide fruitful ground for the optimization of highly potent natural‐product‐based inhibitors of the active form of oncogenic RAS. This integrated approach for screening natural products also holds promise for other “undruggable” targets.
Synthesis of spirostanol saponins via gold(I)‐catalyzed glycosylation in the presence of Ga(OTf)3, In(OTf)3, or HOTf
Authors: Ehianeta Teddy Stephen , Shen Dacheng , Xu Peng , Yu Biao 
Published: June 2019

Summary of main observation and conclusionAn effective approach relying on a Lewis acid‐ or Brønsted acid‐assisted gold(I)‐catalyzed glycosylation has been reported in the synthesis of a panel of the representative natural spirostanol saponins, namely polyphyllin D (1), polyphyllin V (2), dioscin (3), formosanin C (4), and a derivative of polyphyllin D bearing a terminal azide group (5). This approach highlights the engagement of low loadings of Ph3AuPOTf (≤ 0.5 mol%) in the presence of Ga(OTf)3, In(OTf)3, or HOTf (~10mol%) as a co‐catalyst, at practical reaction rates as an alternative to the conventional ~10 mol% loadings of the gold(I) catalyst in the glycosylation. Polyphyllin D (1) was obtained in 41% overall yield over six steps compared to the maximum 30% yield in previous syntheses where conventional donors and promoters were used. By exploiting a regioselective rhamnosylation, a “one‐pot” approach was adopted to assemble 1 and 5, thus further strengthening the efficiency of the gold(I)‐catalyzed glycosylation.