bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of temperature and surface roughness on time-dependent development of wall slip in steady torsional flow of concentrated suspensions
Authors: Aral Birnur K. , Kalyon Dilhan M.
Published: July 2002

A flow visualization technique was applied to investigate the time and temperature-dependent development of wall slip and the rheological behavior of a concentrated suspension, containing 63% by volume solid glass spheres and a poly (butadiene-acrylonitrile-acrylic acid) terpolymer matrix, using steady torsional flow. Flow visualization allowed the concomitant determination of the wall slip velocity and the shear viscosity of the concentrated suspension. The deformation rate, shear stress, and the wall slip velocity values during torsional flow were time dependent and asymptotically reached steady-state values. The characteristic time necessary to reach steady state decreased with increasing shear rate and temperature. Increasing temperature also increased the wall slip velocity. The flow visualization technique was further utilized to determine the yield stress of the suspension directly, which was found to decrease with increasing temperature. Increased surface roughness prevented the wall slip of the concentrated suspension under certain conditions; however, it frequently resulted in the fracture of the suspension samples. Sample fracture became more pronounced with the preshearing of the samples.
Rheological phenomena occurring during the shearing flow of mayonnaise
Authors: Goshawk J. A. , Binding D. M. , Kell D. B. , Goodacre R.
Published: July 2002

A rheometrical study reveals that mayonnaise exhibits apparent wall slip in both small amplitude oscillatory shear flow and torsional flow. Whereas in the case of small amplitude oscillatory shear classical techniques are applicable for extracting bulk material properties, this is not the case for torsional flow. Progressively increasing the shear stress in torsional flow manifests another flow phenomenon that dominates the slip process. It is argued that “particles” within the mayonnaise migrate radially towards the center of the geometry. Spectroscopic techniques are employed to confirm that, following an experiment, material at the rim of the geometry differs from that towards the center. Experiments performed in a cone-and-plate geometry yield results that are qualitatively similar to those obtained in torsional flow tests thus indicating that the migration is not due solely to the radial shear-rate gradient that is present in torsional flow.
Co‐Casting of Al and Al‐Foams
Authors: Ferraris Sara , Santostefano Antonio , De Marco Frediano , Campagnoli Elena , Matteis Paolo , Barbato Antonio , Molina Roberto , Ubertalli Graziano
Published: March 2022

The use of metal foams as permanent cores in casting products is a promising strategy. It aims to improve the properties of the cast components by adding certain foam features (e.g., lightweight, high specific stiffness, impact energy/vibration absorption ability, and good acoustic insulation properties). The use of permanent cores eliminates the steps of removal, treatment, and compulsory recycling for the traditional temporary sand cores. Herein, aluminum metals foams, in the form of bars with a dense continuous outer skin, are inserted in the die of a gravity casting experiment with an Al–Si–Cu–Mg alloy (EN AB.46400). Foams and cast objects are characterized by means of optical emission spectrometry (OES), optical microscopy (OM), scanning electron microscope equipped with energy dispersive spectroscopy (SEM‐EDS), image analysis, and computed tomography (CT).
A Magnetically Separable Pd Single‐Atom Catalyst for Efficient Selective Hydrogenation of Phenylacetylene
Authors: Zhao Linmin , Qin Xuetao , Zhang Xirui , Cai Xiangbin , Huang Fei , Jia Zhimin , Diao Jiangyong , Xiao Dequan , Jiang Zheng , Lu Ruifeng , Wang Ning , Liu Hongyang , Ma Ding
Published: March 2022

Selective hydrogenation of alkynes to alkenes plays a crucial role in the synthesis of fine chemicals. However, how to achieve high selectivity and effective separation of the catalyst and substrate while obtaining high activity is the key for this reaction. In this work, a Pd single‐atom catalyst is anchored to the shell of magnetic core–shell particles that consist of a Ni‐nanoparticles core and a graphene sheets shell (Ni@G) for semi‐hydrogenation of phenylacetylene, delivering 93% selectivity to styrene at full conversion with a robust turnover frequency of 7074 h−1 under mild reaction conditions (303 K, 2 bar H2). Moreover, the catalyst can be recovered promptly from the liquid phase due to its magnetic separability, which makes it present good stability for enduring five cycles. Experimental and theoretical investigations reveal that H2 and substrates are activated by atomically dispersed Pd atoms and Ni@G hybrid support, respectively. The hydrogenation reaction occurs on the surface of Ni@G via hydrogen spillover from the metal to the support. Such a strategy opens an avenue for designing highly active, selective, and magnetically recyclable catalysts for selective hydrogenation in liquid reaction systems.
Tail‐To‐Tail Stereoselective Dimerization of Acrylate Derivatives via Iridium‐Catalyzed Vinylic sp2 C−H Activation
Authors: Kojima Masafumi , Sasaki Mio , Ito Mamoru , Shibata Takanori
Published: March 2022

We describe a cationic Ir‐catalyzed tail‐to‐tail dimerization of aryl acrylates starting from vinylic sp2 C−H activation, which gives industrially useful adipic acid ester derivatives in high yields. We further expanded the reaction to an enantioselective dimerization using aryl methacrylates and achieved the first example of catalytic asymmetric dimerization of acrylate derivatives.

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Synthesis of 3‐Halogenated Quinolin‐2‐Ones from N‐Arylpropynamides via Hypervalent Iodine(III)−Mediated Umpolung Process
Authors: Li Xiaoxian , Zhang Beibei , Zhao Bingyue , Wang Xiaofan , Xu Lingzhi , Du Yunfei
Published: March 2022

The selective synthesis of 3‐halogenated quinolin‐2‐ones from N‐arylpropynamides was realized via umpolung process mediated by phenyliodine(III) diacetate (PIDA) and MX (LiCl, LiBr, CuI). Differing from most previous electrophilic cyclization/halogenation processes that afforded spiro[4,5]trienones, 3‐halogenated quinolin‐2‐ones were obtained through this method with high selectivity.

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Tunable Tannic Acid–Zein Adhesives for Bonding Different Substrates
Authors: Schmidt Gudrun , Smith Kylie H. , Miles Logan J. , Gettelfinger Carissa K. , Hawthorne Jana A. , Fruzyna Erin C. , Wilker Jonathan J.
Published: March 2022

Plant‐based, nontoxic and strong adhesives that can work on different substrates allow for better product recycling. Replacing synthetic adhesives with plant based ones that perform equally well may lead to a more sustainable ecosystem. Adhesives based on zein protein, derived from corn, can be made as strong as Super Glue. Unlike petroleum‐based adhesives, this plant protein is removable and degradable. Here, adhesives from the components zein and tannic acid function well on different substrates such as metals, plastics, and wood. This work presents the properties of selected adhesive formulations including bond strengths when the substrates are changed. To achieve near Super Glue strength, each substrate requires a different adhesive formulation. Temperature‐dependent curing, (potential of hydrogen) changes, and additional variables influence adhesion. Tack testing at room temperature is measured to provide comparisons between initial bonding and that achieved after curing. Adhesion to plastic substrates is less than wood or metal, but still plenty strong to measure. Aging of adhesive solutions as well as water resistance after curing is investigated. Infrared spectroscopy data are correlated with changes in color, age, and pH of adhesives. These new adhesives may lead to a sustainable and cleaner environment.
CeO2 Doping of Hf0.5Zr0.5O2 Thin Films for High Endurance Ferroelectric Memories
Authors: Yu Zhouchangwan , Saini Balreen , Liao Pei‐Jean , Chang Yu‐Kai , Hou Duen‐Huei , Nien Chih‐Hung , Shih Yu‐Chuan , Yeong Sai Hooi , Afanas'ev Valeri , Huang Fei , Baniecki John D. , Mehta Apurva , Chang Chih‐Sheng , Wong H.‐S. Philip , Tsai Wilman , McIntyre Paul C.
Published: March 2022

Ferroelectric switching is demonstrated in CeO2‐doped Hf0.5Zr0.5O2 (HZCO) thin films with application in back‐end‐of‐line compatible embedded memories. At low cerium oxide doping concentrations (2.0–5.6 mol%), the ferroelectric orthorhombic phase is stabilized after annealing at temperatures below 400 °C. HZCO ferroelectrics show reliable switching characteristics beyond 1011 cycles in TiN/HZCO/TiN capacitors, several orders of magnitude greater than identically processed Hf0.5Zr0.5O2 (HZO) capacitors, without sacrificing polarization and retention. Internal photoemission and photoconductivity experiments show that CeO2‐doping introduces in‐gap states in HZCO that are nearly aligned with TiN Fermi level, facilitating electron injection through these states. The enhanced average bulk conduction, which may lead to more uniform thermal dissipation in the HZCO films, delays irreversible degradation via breakdown that leads to device failure after repeated programming cycles.
Manipulating Strain in Transistors: From Mechanically Sensitive to Insensitive
Authors: Li Ming‐Zheng , Guo Liang‐Chao , Liu Gang , Yan Yan , Zhang Meng , Han Su‐Ting , Zhou Ye
Published: March 2022

The rapid development of flexible and stretchable materials has portrayed a bright future of flexible electronics in pursuing the concept of “Internet of Things.” Transistors, as one of the fundamental units in electronic devices, are being widely studied in exploring the possibility of increasing their flexibility and/or stretchability to fulfill the requirement in flexible electronics, from basic logic circuits to intelligent devices. However, the mechanical stimuli induced by bending and stretching activities can lead to unexpected performance degradations. Here, an in‐depth analysis of approaches to modulating the sensitivity of flexible and stretchable transistors, from a mechanically sensitive type to an insensitive type is demonstrated. Starting with the structural design, the mechanism of sensitivity modulation is explicitly analyzed, such as effects based on the modulation of dielectric capacitance, conductance of active channels, or contact resistance at interfaces in sensitive transistors and strain patterning technology applied to an insensitive type. The sensitivity modulation for transistors is further analyzed regarding material utilization based on different dimensional forms. Finally, the potential applications where flexible and stretchable transistors can be employed as an outlook are discussed.
Inverted Anode Structure for Long‐Life Lithium Metal Batteries
Authors: Li Dongdong , Xie Chuan , Gao Yuan , Hu Hong , Wang Lei , Zheng Zijian
Published: March 2022

Unlimited growth of lithium dendrites is undesirable yet preventing this still remains a challenge for pursuing high‐energy battery systems. Serious safety hazards caused by short circuit and fire demand accurate control of the nucleation location of lithium deposition. Here, an inverted anode structure enabled by simple flipping of carbon fabric after lithium electrodeposition is reported. In contrast to traditional strategies of using regular upright structure, the inverted anode structure can guide a directional deposition of lithium to the bottom of the anode. The low nucleation barrier originating from the bottom lithium metal can induce a superior bottom‐up deposition process. Lithium dendrite issues can thus be significantly alleviated, and approximately twice the cycle life extension of the lithium metal anode is achieved. More importantly, the solid electrolyte interphase immersed in the inverted anode structure is extremely stable, resulting from the well supporting skeleton of the surrounding carbon fabric fibers. The assembled lithium metal batteries show excellent cycling stability with a capacity retention per cycle of 99.98%, i.e., the battery capacity still retains 82.3% after 750 charge/discharge cycles. This simple inversion strategy is universal and can be extended to other porous current collectors, such as thin conductive fabric, and offers great opportunities for next‐generation lithium‐based batteries.
A DNA‐Based Plasmonic Nanodevice for Cascade Signal Amplification
Authors: Liu Fengsong , Li Na , Shang Yingxu , Wang Yiming , Liu Qing , Ma Zhentao , Jiang Qiao , Ding Baoquan
Published: March 2022

Here, we describe a DNA circuit‐aided, origami nanodevice‐based plasmonic system, which performs DNA‐regulated, cascade amplification of faint chemical/biological signals. In this system, two gold‐nanorods (GNRs) are co‐assembled onto a DNA lock‐containing, tweezer‐like DNA origami template. Logic circuits serve as recognition and amplification elements for specific messengers, producing DNA keys for driving conformational changes of the plasmonic nanodevices. In the presence of input signals including nucleic acids, adenosines, chiral tyrosinamides or specific receptors expressed by tumor cells, the plasmonic nanodevices can be activated to perform dynamic structural motions, reporting robust responses via plasmonic circular dichroism (CD) spectral changes. This DNA nanodevice‐based system provides a different design to enrich the strategies for constructing synthetic nanomachines, enabling the customized bottom‐up nanostructure construction for sensitive biological signaling.
Chemical Biology Tools for Protein Lysine Acylation
Authors: Xie Yusheng , Du Shubo , Liu Zhiyang , Liu Min , Xu Zhiqiang , Wang Xiaojie , Kee Jia Xuan , Yi Fan , Sun Hongyan , Yao Shao Q.
Published: March 2022

Lysine acylation plays pivotal roles in cell physiology, including DNA transcription and repair, signal transduction, immune defense, metabolism, and many other key cellular processes. Molecular mechanisms of dysregulated lysine acylation are closely involved in the pathophysiological progress of many human diseases, most notably cancers. In recent years, chemical biology tools have become instrumental in studying the function of post‐translational modifications (PTMs), identifying new “writers”, “erasers” and “readers”, and in targeted therapies. Here, we describe key developments in chemical biology approaches that have advanced the study of lysine acylation and its regulatory proteins (2016–2021). We further discuss the discovery of ligands (inhibitors and PROTACs) that are capable of targeting regulators of lysine acylation. Next, we discuss some current challenges of these chemical biology probes and suggest how chemists and biologists can utilize chemical probes with more discriminating capacity. Finally, we suggest some critical considerations in future studies of PTMs from our perspective.
Achieving 37.1% Green Electroluminescent Efficiency and 0.09 eV Full Width at Half Maximum Based on a Ternary Boron‐Oxygen‐Nitrogen Embedded Polycyclic Aromatic System
Authors: Cai Xinliang , Xue Jianan , Li Chenglong , Liang Baoyan , Ying Ao , Tan Yao , Gong Shaolong , Wang Yue
Published: March 2022

Herein, a ternary boron‐oxygen‐nitrogen embedded polycyclic aromatic hydrocarbon with multiple resonance thermally activated delayed fluorescence (MR‐TADF), namely DBNO, is developed by adopting theparaboron‐π‐boron andparaoxygen‐π‐oxygen strategy. The designed molecule presents a vivid green emission with a high photoluminescence quantum yield (96 %) and an extremely narrow full width at half maximum (FWHM) of 19 nm/0.09 eV, which surpasses all previously reported green TADF emitters to date. In addition, the long molecular structure along the transition dipole moment direction endows it with a high horizontal emitting dipole ratio of 96 %. The organic light‐emitting diode (OLED) based on DBNO reveals a narrowband green emission with a peak at 504 nm and a FWHM of 24 nm/0.12 eV. Particularly, a significantly improved device performance is achieved by the TADF‐sensitization (hyperfluorescence) mechanism, presenting a FWHM of 27 nm and a maximum external quantum efficiency (EQE) of 37.1 %.
Operando Spectroscopy Unveils the Catalytic Role of Different Palladium Oxidation States in CO Oxidation on Pd/CeO2 Catalysts
Authors: Muravev Valery , Simons Jérôme F. M. , Parastaev Alexander , Verheijen Marcel A. , Struijs Job J. C. , Kosinov Nikolay , Hensen Emiel J. M.
Published: March 2022

Aiming at knowledge‐driven design of novel metal–ceria catalysts for automotive exhaust abatement, current efforts mostly pertain to the synthesis and understanding of well‐defined systems. In contrast, technical catalysts are often heterogeneous in their metal speciation. Here, we unveiled rich structural dynamics of a conventional impregnated Pd/CeO2 catalyst during CO oxidation. In situ X‐ray photoelectron spectroscopy and operando X‐ray absorption spectroscopy revealed the presence of metallic and oxidic Pd states during the reaction. Using transient operando infrared spectroscopy, we probed the nature and reactivity of the surface intermediates involved in CO oxidation. We found that while low‐temperature activity is associated with sub‐oxidized and interfacial Pd sites, the reaction at elevated temperatures involves metallic Pd. These results highlight the utility of the multi‐technique operando approach for establishing structure–activity relationships of technical catalysts.
Gold‐Catalyzed Desymmetric Lactonization of Alkynylmalonic Acids Enabled by Chiral Bifunctional P,N ligands
Authors: Lin Bijin , Yang Tilong , Zhang Dequan , Zhou Yang , Wu Liangliang , Qiu Jingfei , Chen Gen‐Qiang , Che Chi‐Ming , Zhang Xumu
Published: March 2022

Due to the linear coordination nature of gold(I) catalysts, achieving high enantiocontrol in asymmetric gold catalysis is a great challenge. To improve the enantiocontrol of gold catalysis, an ion‐pairing strategy was therefore proposed. A series of bifunctional P,N ligands based on chiral spirocyclic and biaryl scaffolds were synthesized and applied in the gold(I)‐catalyzed desymmetric lactonization of alkynylmalonic acids. A wide range of chiral lactones containing an α‐position quaternary stereocenter were synthesized with high yields, excellent regioselectivity and enantioselectivity under mild reaction conditions. The synthetic utilities of the current reaction were demonstrated by gram‐scale synthesis and transformations of chiral lactones. The origin of enantioselectivity and the role of the alcohol additive were elucidated via control experiments and DFT calculations.
Metal‐Free Ring‐Opening Metathesis Polymerization with Hydrazonium Initiators**
Authors: Quach Phong K. , Hsu Jesse H. , Keresztes Ivan , Fors Brett P. , Lambert Tristan H.
Published: March 2022

The ring‐opening metathesis polymerization (ROMP) of cyclopropenes using hydrazonium initiators is described. The initiators, which are formed by the condensation of 2,3‐diazabicyclo[2.2.2]octane and an aldehyde, polymerize cyclopropene monomers by a sequence of [3+2] cycloaddition and cycloreversion reactions. This process generates short chain polyolefins (Mn≤9.4 kg mol−1) with relatively low dispersities (Đ≤1.4). The optimized conditions showed efficiency comparable to that achieved with Grubbs’ 2nd generation catalyst for the polymerization of 3‐methyl‐3‐phenylcyclopropene. A positive correlation between monomer to initiator ratio and degree of polymerization was revealed through NMR spectroscopy.
Pentafluorphosphato‐Phenylalanine: Amphiphile Phosphotyrosinmimetika mit Fluor‐spezifischen Proteinwechselwirkungen
Authors: Accorsi Matteo , Tiemann Markus , Wehrhan Leon , Finn Lauren M. , Cruz Ruben , Rautenberg Max , Emmerling Franziska , Heberle Joachim , Keller Bettina G. , Rademann Jörg
Published: March 2022

Phosphotyrosinreste sind essenzielle funktionale Schalter in Gesundheit und Krankheit. Daher sind Phosphotyrosin‐Biomimetika entscheidend für die Entwicklung von chemischen Werkzeugen und Wirkstoffmolekülen. Hier beschreiben wir die Entdeckung und Untersuchung von Pentafluorphosphato‐Aminosäuren als neuartige Phosphotyrosinmimetika. Ein mildes Pentafluorierungsprotokoll wurde entwickelt, zwei PF5‐Aminosäuren hergestellt und für die Peptidsynthese verwendet. Ihre Strukturen, Reaktivitäten und fluorspezifischen Wechselwirkungen wurden mittels NMR‐ und IR‐Spektroskopie, Röntgenstreuung und biologischen Assays untersucht. Das monoanionische PF5‐Motiv weist einen amphiphilen Charakter auf und bindet an hydrophobe Oberflächen, Wassermoleküle und Proteinbindungstaschen mittels Ladungs‐ und H−F‐Brückenwechselwirkungen. Die neuen Motive binden 25‐ bis 30‐fach stärker an die Phosphotyrosinbindungsstelle der Proteintyrosin‐Phosphatase PTP1B als das derzeit beste Biomimetikum, wie durch computergestützte Methoden wie Moleküldynamiksimulationen rationalisiert werden konnte.
Catalytic DNA Polymerization Can Be Expedited by Active Product Release**
Authors: Moerman Pepijn G. , Gavrilov Momcilo , Ha Taekjip , Schulman Rebecca
Published: March 2022

The sequence‐specific hybridization of DNA facilitates its use as a building block for designer nanoscale structures and reaction networks that perform computations. However, the strong binding energy of Watson–Crick base pairing that underlies this specificity also causes the DNA dehybridization rate to depend sensitively on sequence length and temperature. This strong dependency imposes stringent constraints on the design of multi‐step DNA reactions. Here we show how an ATP‐dependent helicase, Rep‐X, can drive specific dehybridization reactions at rates independent of sequence length, removing the constraints of equilibrium on DNA hybridization and dehybridization. To illustrate how this new capacity can speed up designed DNA reaction networks, we show that Rep‐X extends the range of conditions where the primer exchange reaction, which catalytically adds a domain provided by a hairpin template to a DNA substrate, proceeds rapidly.
Sustaining Electron Transfer Pathways Extends Biohybrid Photoelectrode Stability to Years
Authors: Friebe Vincent M. , Barszcz Agata J. , Jones Michael R. , Frese Raoul N.
Published: March 2022

The exploitation of natural photosynthetic enzymes in semi‐artificial devices constitutes an attractive and potentially sustainable route for the conversion of solar energy into electricity and solar fuels. However, the stability of photosynthetic proteins after incorporation in a biohybrid architecture typically limits the operational lifetime of biophotoelectrodes to a few hours. Here, we demonstrate ways to greatly enhance the stability of a mesoporous electrode coated with the RC‐LH1 photoprotein from Rhodobacter sphaeroides. By preserving electron transfer pathways, we extended operation under continuous high‐light to 33 days, and operation after storage to over two years. Coupled with large photocurrents that reached peak values of 4.6 mA cm−2, the optimized biophotoelectrode produced a cumulative output of 86 C cm−2, the largest reported performance to date. Our results demonstrate that the factor limiting stability is the architecture surrounding the photoprotein, and that biohybrid sensors and photovoltaic devices with operational lifetimes of years are feasible.
A Class of Readily Tunable Planar‐Chiral Cyclopentadienyl Rhodium(III) Catalysts for Asymmetric C–H Activation
Authors: Yan Xiaoqiang , Jiang Jijun , Wang Jun
Published: March 2022

Chiral half‐sandwich cyclopentadienyl rhodium(III) (CpRhIII) complexes are powerful catalysts for promoting asymmetric C−H activation reactions. Their preparation normally involved linking or embedding the Cp motif to or into a certain chiral backbone to forge the so‐called chiral Cp ligand. However, preparation of a planar‐chiral CpRhIII catalyst bearing a non‐chiral Cp ligand remains a formidable challenge and is rarely reported. We describe herein an unusual class of planar‐chiral rhodium catalysts bearing non‐chiral Cp ligands. Different from existing ones, this catalyst is readily tunable. Ten planar‐chiral only CpRhIII catalysts were prepared with ease, and successfully used in two enantioselective C−H activation reactions. Given its convenient synthesis and high structural tunability, these catalysts are expected to find more utilities in asymmetric C−H activation.
Dinitrogen Coordination to a High‐Spin Diiron(I/II) Species
Authors: Torres Juan F. , Oi Collin H. , Moseley Ian P. , El‐Sakkout Nabila , Knight Brian J. , Shearer Jason , García‐Serres Ricardo , Zadrozny Joseph M. , Murray Leslie J.
Published: March 2022

Dinitrogen coordination to iron centers underpins industrial and biological fixation in the Haber–Bosch process and by the FeM cofactors in the nitrogenase enzymes. The latter employ local high‐spin metal centers; however, iron–dinitrogen coordination chemistry remains dominated by low‐valent states, contrasting the enzyme systems. Here, we report a high‐spin mixed‐valent cis‐(μ‐1,2‐dinitrogen)diiron(I/II) complex [(FeBr)2(μ‐N2)Lbis]− (2), where [Lbis]− is a bis(β‐diketiminate) cyclophane. Field‐applied Mössbauer spectra, dc and ac magnetic susceptibility measurements, and computational methods support a delocalized S=7/2 Fe2N2 unit with D=−5.23 cm−1 and consequent slow magnetic relaxation.
Slow Synthesis Methodology‐Directed Immiscible Octahedral PdxRh1−x Dual‐Atom‐Site Catalysts for Superior Three‐Way Catalytic Activities over Rh
Authors: Tan Zhe , Haneda Masaaki , Kitagawa Hiroshi , Huang Bo
Published: March 2022

This study provided an effective strategy to construct dual‐atom sites by solid–solution alloying. A slow synthesis methodology was established for the solid–solution preparations as dual‐atom‐site catalysts. The atomic‐level homogeneous PdxRh1−x dual‐atom‐site catalysts were successfully synthesized over the whole composition range, as evidenced by X‐ray powder diffraction and scanning transmission electron microscope energy‐dispersive X‐ray spectroscopy mapping measurements. The challenging morphology formation in the immiscible alloys was achieved by an energy‐controlling process as the octahedral Rh‐rich alloys. The Pd0.3Rh0.7 dual‐atom‐site catalyst had unique surface states to activate the key reactants of CO and NO in the complex three‐way catalytic reactions, and it performed significantly better than pure Rh.
Boosting the Productivity of Electrochemical CO2Reduction to Multi‐Carbon Products by Enhancing CO2Diffusion through a Porous Organic Cage
Authors: Chen Chunjun , Yan Xupeng , Wu Yahui , Liu Shoujie , Zhang Xiudong , Sun Xiaofu , Zhu Qinggong , Wu Haihong , Han Buxing
Published: March 2022

Electroreduction of CO2into valuable fuels and feedstocks offers a promising way for CO2utilization. However, the commercialization is limited by the low productivity. Here, we report a strategy to enhance the productivity of CO2electroreduction by improving diffusion of CO2to the surface of catalysts using porous organic cages (POCs) as an additive. It was noted that the Faradaic efficiency (FE) of C2+ products could reach 76.1 % with a current density of 1.7 A cm−2when Cu‐nanorod(nr)/CC3 (one of the POCs) was used, which were much higher than that using Cu‐nr. Detailed studies demonstrated that the hydrophobic pores of CC3 can adsorb a large amount of CO2for the reaction, and the diffusion of CO2in the CC3 to the nanocatalyst surface is easier than that in the liquid electrolyte. Thus, more CO2molecules make contact with the nanocatalysts in the presence of CC3, enhancing CO2reduction and inhibiting generation of H2.
Constructing Cu−C Bonds in a Graphdiyne‐Regulated Cu Single‐Atom Electrocatalyst for CO2 Reduction to CH4
Authors: Shi Guodong , Xie Yunlong , Du Lili , Fu Xinliang , Chen Xiaojie , Xie Wangjing , Lu Tong‐Bu , Yuan Mingjian , Wang Mei
Published: March 2022

Regulating intermediates through elaborate catalyst design to control the reaction direction is crucial for promoting the selectivity of electrocatalytic CO2‐to‐CH4. M−C (M=metal) bonds are particularly important for tuning the multi‐electron reaction; however, its construction in nanomaterials is challenging. Here, via rational design of in situ anchoring of Cu SAs (single atoms) on the unique platform graphdiyne, we firstly realize the construction of a chemical bond Cu−C (GDY). In situ Raman spectroelectrochemistry and DFT calculations confirm that due to the fabrication of the Cu−C bond, during CO2 reduction, the formation of *OCHO intermediates is dominant rather than *COOH on Cu atoms, facilitating the formation of CH4. Therefore, we find that constructing the Cu−C bond in Cu SAs/GDY can supply an efficient charge transfer channel, but most importantly control the reaction intermediates and guide a more facile reaction pathway to CH4, thereby significantly boosting its catalytic performance. This work provides new insights on enhancing the selectivity for CO2RR at the atomic level.
Pentafluorophosphato‐Phenylalanines: Amphiphilic Phosphotyrosine Mimetics Displaying Fluorine‐Specific Protein Interactions
Authors: Accorsi Matteo , Tiemann Markus , Wehrhan Leon , Finn Lauren M. , Cruz Ruben , Rautenberg Max , Emmerling Franziska , Heberle Joachim , Keller Bettina G. , Rademann Jörg
Published: March 2022

Phosphotyrosine residues are essential functional switches in health and disease. Thus, phosphotyrosine biomimetics are crucial for the development of chemical tools and drug molecules. We report here the discovery and investigation of pentafluorophosphato amino acids as novel phosphotyrosine biomimetics. A mild acidic pentafluorination protocol was developed and two PF5‐amino acids were prepared and employed in peptide synthesis. Their structures, reactivities, and fluorine‐specific interactions were studied by NMR and IR spectroscopy, X‐ray diffraction, and in bioactivity assays. The mono‐anionic PF5 motif displayed an amphiphilic character binding to hydrophobic surfaces, to water molecules, and to protein‐binding sites, exploiting charge and H−F‐bonding interactions. The novel motifs bind 25‐ to 30‐fold stronger to the phosphotyrosine binding site of the protein tyrosine phosphatase PTP1B than the best current biomimetics, as rationalized by computational methods, including molecular dynamics simulations.
Making sense of the black‐boxes: Toward interpretable text classification using deep learning models
Authors: Tao Jie , Zhou Lina , Hickey Kevin
Published: March 2022

Text classification is a common task in data science. Despite the superior performances of deep learning based models in various text classification tasks, their black‐box nature poses significant challenges for wide adoption. The knowledge‐to‐action framework emphasizes several principles concerning the application and use of knowledge, such as ease‐of‐use, customization, and feedback. With the guidance of the above principles and the properties of interpretable machine learning, we identify the design requirements for and propose an interpretable deep learning (IDeL) based framework for text classification models. IDeL comprises three main components: feature penetration, instance aggregation, and feature perturbation. We evaluate our implementation of the framework with two distinct case studies: fake news detection and social question categorization. The experiment results provide evidence for the efficacy of IDeL components in enhancing the interpretability of text classification models. Moreover, the findings are generalizable across binary and multi‐label, multi‐class classification problems. The proposed IDeL framework introduce a unique iField perspective for building trusted models in data science by improving the transparency and access to advanced black‐box models.
Evaluation of electroencephalography biomarkers for Angelman syndrome during overnight sleep
Authors: Levin Yuval , Hosamane Nishitha S. , McNair Taylor E. , Kunnam Shrujana S. , Philpot Benjamin D. , Fan Zheng , Sidorov Michael S.
Published: March 2022

Angelman syndrome (AS) is a neurodevelopmental disorder caused by loss‐of‐function mutations in the maternal copy of the UBE3A gene. AS is characterized by intellectual disability, impaired speech and motor skills, epilepsy, and sleep disruptions. Multiple treatment strategies to re‐express functional neuronal UBE3A from the dormant paternal allele were successful in rodent models of AS and have now moved to early phase clinical trials in children. Developing reliable and objective AS biomarkers is essential to guide the design and execution of current and future clinical trials. Our prior work quantified short daytime electroencephalograms (EEGs) to define promising biomarkers for AS. Here, we asked whether overnight sleep is better suited to detect AS EEG biomarkers. We retrospectively analyzed EEGs from 12 overnight sleep studies from individuals with AS with age and sex‐matched Down syndrome and neurotypical controls, focusing on low frequency (2–4 Hz) delta rhythms and sleep spindles. Delta EEG rhythms were increased in individuals with AS during all stages of overnight sleep, but overnight sleep did not provide additional benefit over wake in the ability to detect increased delta. Abnormal sleep spindles were not reliably detected in EEGs from individuals with AS during overnight sleep, suggesting that delta rhythms represent a more reliable biomarker. Overall, we conclude that periods of wakefulness are sufficient, and perhaps ideal, to quantify delta EEG rhythms for use as AS biomarkers.

Lay Summary

Electroencephalography (EEG) is a safe and reliable way of measuring abnormal brain activity in Angelman syndrome. We found that low‐frequency “delta” EEG rhythms are increased in individuals with Angelman syndrome during all stages of overnight sleep. Delta rhythms can be used as a tool to measure improvement in future clinical trials.
Structural Dynamics Support Electrostatic Interactions in the Active Site of Adenylate Kinase
Authors: Lawal Monsurat Motunrayo , Vaissier Welborn Valerie
Published: March 2022

Electrostatic preorganization as well as structural and dynamic heterogeneity are often used to rationalize the remarkable catalytic efficiency of enzymes. However, they are often presented as incompatible because the generation of permanent electrostatic effects implies that the protein structure remains rigid. Here, we use a metric, electric fields, that can treat electrostatic contributions and dynamics effects on equal footing, for a unique perspective on enzymatic catalysis. We find that the residues that contribute the most to electrostatic interactions with the substrate in the active site of Adenylate Kinase (our working example) are also the most flexible residues. Further, entropy‐tuning mutations raise flexibility at the picosecond timescale where more conformations can be visited on short time periods, thereby softening the sharp heterogeneity normally visible at the microsecond timescale.
Investigation of a large‐scale adaptive concrete beam with integrated fluidic actuators
Authors: Burghardt Timon , Kelleter Christian , Bosch Matthias , Nitzlader Markus , Bachmann Matthias , Binz Hansgeorg , Blandini Lucio , Sobek Werner
Published: March 2022

As the world population keeps growing, so does the demand for new construction. Considering material resources are limited, it will be unfeasible to meet such demand employing conventional construction methods. A new resource‐saving approach is provided by adaptive structures. Using sensors, actuators and control units, structures are enabled to adapt to loads, for example, to compensate for deformations. Since deformations are dominant in the design of bending‐stressed load‐bearing structures, adaptivity enables such structures to be realized using less material and achieving the same load‐bearing capacity in comparison to conventional designs. This article presents a concrete beam of typical building dimensions that compensates deflections by means of integrated fluidic actuators. These actuators offer the possibility of reacting optimally to general loading. The investigation is carried out on an approximately 4‐m‐long beam with integrated hydraulic actuators. To ensure the overall functionality, accurate dimensioning of the beam as well as the hydraulic system is mandatory. Analytical design of the beam and actuation system are carried out for predimensioning. Experimental testing validates the function and demonstrates that the adaptive beam works as predicted. A fully compensation in deflection is possible. Therefore, a significant increase in load‐bearing capacity is possible with the same material input compared to conventional beams.
Macrocyclic Donor‐Acceptor Dyads Composed of Oligothiophene Half‐Cycles and Perylene Bisimides
Authors: Bold Kevin , Stolte Matthias , Shoyama Kazutaka , Krause Ana‐Maria , Schmiedel Alexander , Holzapfel Marco , Lambert Christoph , Würthner Frank
Published: March 2022

A series of donor‐acceptor (D−A) macrocyclic dyads consisting of an electron‐poor perylene bisimide (PBI) π‐scaffold bridged with electron‐rich α‐oligothiophenes bearing four, five, six and seven thiophene units between the two phenyl‐imide substituents has been synthesized and characterized by steady‐state UV/Vis absorption and fluorescence spectroscopy, cyclic and differential pulse voltammetry as well as transient absorption spectroscopy. Tying the oligothiophene strands in a conformationally fixed macrocyclic arrangement leads to a more rigid π‐scaffold with vibronic fine structure in the respective absorption spectra. Electrochemical analysis disclosed charged state properties in solution which are strongly dependent on the degree of rigidification within the individual macrocycle. Investigation of the excited state dynamics revealed an oligothiophene bridge size‐dependent fast charge transfer process for the macrocyclic dyads upon PBI subunit excitation.
Chalcogen Bonding with Diaryl Ditellurides: Evidence from Solid State and Solution Studies.
Authors: Weiss Robin , Aubert Emmanuel , Groslambert Loic , Pale Patrick , Mamane Victor
Published: March 2022

The chalcogen bonding (ChB) ability of Te is studied in symmetrical diaryl ditellurides ArTeTeAr. Among the two Te σ‐holes, the one along the less polarized Te−Te bond was calculated as the more electropositive. This counter‐intuitive situation is due to the hyperconjugation contribution from Te lone pair to the σ* of the adjacent Te which coincides with σ‐hole along the more polarized Te−Ar bond. ArTeTeAr showed notable structural features in the solid state as a result of intermolecular Te⋅⋅⋅Te ChB, such as a Te4 rectangle through dimer aggregation or a triangular Te3 motif, where one Te interacts with both Te atoms of a neighboring molecule through both its σ‐hole and lone pair, in a slightly frustrated geometry. Lewis acidity of ArTeTeAr was also evaluated by NMR with R3PO as σ‐hole acceptors in different solvents. Thus, 125Te NMR allowed monitoring Te⋅⋅⋅O interaction and delivering association constants (Ka) for 1 : 1 adducts. The highest value of Ka=90 M−1 was measured for the adduct between ArTeTeAr bearing CF3 groups and Et3PO in cyclohexane. Notably, by using nBu3PO, Te⋅⋅⋅O interaction was revealed by 19F‐1H HOESY showing spatial proximity between CF3 and CH3 of nBu3PO.
Azetidines‐Containing Fluorescent Purine Analogs: Synthesis and Photophysical Properties
Authors: Hadidi Kaivin , Tor Yitzhak
Published: March 2022

Analogues of N,N‐dimethyladenine exploiting both thieno‐and isothiazolo‐pyrimidine cores were modified with 3‐subsituted azetidines to yield visibly emissive and responsive fluorophores. The emission quantum yields, among the highest seen for purine analogues (0.64 and 0.77 in water and dioxane respectively), correlated with the Hammett inductive constants of the substituents on the azetidine ring. Ribosylation of the difluoroazetidino‐modified nucleobase yielded an emissive nucleoside that displayed a substantially lower emission quantum yield in water, compared to the precursor nucleobase. Importantly, high emission quantum yield was restored in deuterium oxide, which highlights the potential impact of the sugar moiety on the photophysical features of fluorescent nucleosides, a functionality usually considered non‐chromophoric and photophysically benign.
Magnetic Resonance Imaging of Tumor‐Infiltrating Lymphocytes by Anti‐CD3‐Conjugated Iron Oxide Nanoparticles
Authors: Pournoori Negin , Oghabian Mohammad Ali , Irajirad Rasoul , Muhammadnejad Samad , Delavari H. Hamid
Published: March 2022

Immune checkpoint blockade, considered a revolutionary approach in cancer treatment, is only effective in patients with high tumor‐infiltrating lymphocytes (TILs). This work aimed to investigate the feasibility of targeted contrast agent (CA) based on dextran‐coated superparamagnetic iron oxide nanoparticles (SPIONs‐DEX) for TILs detection by magnetic resonance imaging (MRI) studies. To do so, we synthesized an MRI CA by conjugating SPIONs‐DEX to an anti‐CD3 monoclonal antibody via cyanogen bromide as a cross‐linker. In vitro assessments demonstrated the higher labeling efficiency of the developed CA to CD3+ lymphocytes compared to SPIONs‐DEX. In vivo MRI of a xenograft model of CD3+ lymphocytes revealed the significant signal loss after the intravenous injection of the bioconjugate by ∼34 % and 21 % in T2*‐weighted and T2‐weighted images, respectively. The histopathological evaluation of xenograft tumors confirmed the labeling of lymphocytes by the targeted CA. This approach could open up a new horizon in the non‐invasive assessment of TILs to identify patients eligible for immunotherapy.
Lysine‐Functionalized SnO2for Efficient CO2Electroreduction into Formate
Authors: Lin Chen , Xu Zifan , Kong Xiangdong , Zheng Han , Geng Zhigang , Zeng Jie
Published: March 2022

Electroreduction of CO2to HCOO−can be considered as the most economically valuable process. Herein, we developed lysine‐functionalized SnO2nanoparticles (SnO2‐lys) as an efficient catalyst for the electroreduction of CO2into HCOO−. During CO2electroreduction, SnO2‐lys achieved a Faradaic efficiency for HCOO−of higher than 80% over a wide range of applied potentials from −0.5 V to −2.3 V versus reversible hydrogen electrode (vs. RHE). Notably, the partial current density for HCOO−reached as high as −351.9 mA cm−2at −2.3 Vvs. RHE. On account of kinetic analysis and mechanistic study, lysine‐functionalized SnO2facilitated faradaic process and accelerated reaction kinetics via enhancing the CO2activation, thus promoting the catalytic performance of the electroreduction of CO2into HCOO−.
Contemporary machine learning applications in agriculture: Quo Vadis?
Authors: Mahmood Atif , Tiwari Amod Kumar , Singh Sanjay Kumar , Udmale Sandeep S.
Published: March 2022

Agricultural automation is an emerging subject today to accomplish the food demands of individuals across the globe. Machine learning is one such agricultural automation tool that has been adopted briskly in the recent decade due to its ability to process countless input data and handle non‐linear tasks. Availability and continuous development of agricultural data led the machine learning pervasive in multiple aspects of agriculture. This paper systematically analyses and summarizes the 81 quality research efforts published in the past decade dedicated to the various contemporary machine learning applications in agriculture and food production systems. We examined and categorized each agricultural problem under study into four categories and each category into its subcategories. The finding demonstrates the contemporary applications of machine learning in broad agricultural subcategories and determines where it is heading shortly; based upon contributions of researchers, utilization of machine learning models/algorithms, and the availability of agricultural datasets. Through the analysis, it is discovered that the current innovation can help the improvement of agricultural automation to accomplish the advantages of minimal cost, high efficiency, and better precision. This paper can serve as an investigatory guide for researchers, academicians, engineers, and manufacturers to understand and apply modern and upgraded cognitive technologies to each subcategory of the agricultural sector.
Energetic Ordering of Hydrogen Bond Strengths in Methanol‐Water Clusters: Insights via Molecular Tailoring Approach
Authors: Patkar Deepak , Ahirwar Mini Bharati , Deshmukh Milind M.
Published: March 2022

In this work, we examine the strength of various types of individual hydrogen bond (HB) in mixed methanol‐water MnWm, (n+m=2 to 7) clusters, with an aim to understand the relative order of their strength, using our recently proposed molecular tailoring‐based approach (MTA). Among all the types of HB, it is observed that the OM−H…OW HBs are the strongest (6.9 to 12.4 kcal mol−1). The next ones are OM−H…OM HBs (6.5 to 11.6 kcal mol−1). The OW−H…OW (0.2 to 10.9 kcal mol−1) and OW−H…OM HBs (0.3 to 10.3 kcal mol−1) are the weakest ones. This energetic ordering of HBs is seen to be different from the respective HB energies in the dimer i. e., OM−H…OM (5.0 to 6.0 kcal mol−1)>OW−H…OM (1.5 to 6.0 kcal mol−1)>OM−H…OW (3.8 to 5.6 kcal mol−1)>OW−H…OW (1.2 to 5.0 kcal mol−1). The plausible reason for the difference in the HB energy ordering may be attributed to the increase or decrease in HB strengths due to the formation of cooperative or anti‐cooperative HB networks. For instance, the cooperativity contribution towards the different types of HB follows: OM−H…OW (2.4 to 8.6 kcal mol−1)>OM−H…OM (1.3 to 6.3 kcal mol−1)>OW−H…OW (−1.0 to 6.5 kcal mol−1)>OW−H…OM (−1.2 to 5.3 kcal mol−1). This ordering of cooperativity contribution is similar to the HB energy ordering obtained by the MTA‐based method. It is emphasized here that, the interplay between the cooperative and anti‐cooperative contributions are indispensable for the correct energetic ordering of these HBs.
Diagnostic value of endometrial cytology and related technology
Authors: Munakata Satoru
Published: March 2022

Background

Endometrial cytology is not much popular in the world, but is commonly used in a few countries. Although cytomorphological evaluation of endometrial cytology is complicating, recent advance in technology helps improve diagnostic accuracy. In addition, new reporting system, The Yokohama System, has been introduced as a standard reporting system resembling The Bethesda System of the uterine cervical cytology. Although sample standardization is one of the causes in diagnostic problem, it was solved by liquid‐based cytology (LBC) technology. In addition, standardized diagnostic algorithm by cytomorphological assessment of LBC samples, the Osaki Study Group (OSG) method, was recently proposed as a reliable and reproducible method. LBC can be utilized for ancillary methods. Application of immunocytochemistry and molecular technology on endometrial cytology samples has been studied to improve diagnostic accuracy. Recent progress of molecular technology has revealed many driver gene mutations in endometrial cancer and its precursors. Surprisingly, many studies revealed that even normal endometrial tissue had driver gene mutations.

Conclusion

Based on the recent advance in knowledge of molecular profile of endometrial lesions and normal endometrial tissue, endometrial cytology will gain much power in clinical usefulness.