bluuebunny/crossref_metadata_2025_split huggingface dataset:
Engineering Aggregation‐Resistant MXene Nanosheets As Highly Conductive and Stable Inks for All‐Printed Electronics
Authors: Tang Xiaowu , Murali G. , Lee Hyungjin , Park Seongmin , Lee Seongeun , Oh Sun Moo , Lee Jihoon , Ko Tae Yun , Koo Chong Min , Jeong Yong Jin , An Tae Kyu , In Insik , Kim Se Hyun 
Published: April 2021

AbstractMXenes are interesting 2D materials that have been considered as attractive frontier materials for potential applications in the fields of energy and electronic devices due to their excellent optoelectronic properties including metallic conductivity and high optical transparency. However, it is still challenging to achieve compatibility for the as‐synthesized MXene nanosheets with simple solution‐deposition and patterning processes because of their limited solubility in many solvents. Here, a promising strategy is developed for obtaining alcohol‐dispersible MXene nanosheets suitable for all‐printed electronics while enhancing their electrical conductivity. This strategy includes a trifluoroacetic acid treatment—applied in order to contribute to the modification of intercalants between the MXene nanosheets—and achieves long‐term dispersion of the MXene in alcoholic media and balanced jetting conditions during the electrohydrodynamic printing process. Furthermore, the high conductivity levels of the treated MXenes allow their printed patterns to be applied as gate and source/drain electrodes in all‐printed logic circuits, displaying good and robust operation in transistors, inverters, and NAND, and NOR logic gates. This study provides a promising approach for modifying MXene nanosheets with the purpose of achieving desirable properties suitable for large‐area printing processes, suggesting the feasibility of using MXene in practical applications involving all‐printed electronics.
Nanoagent‐Promoted Mild‐Temperature Photothermal Therapy for Cancer Treatment
Authors: Gao Ge , Sun Xianbao , Liang Gaolin 
Published: April 2021

AbstractPhotothermal therapy (PTT), which utilizes near‐infrared light‐absorbing agents to ablate tumor, has emerged as a highly promising anticancer strategy and received intensive clinical trials in recent years. Mild‐temperature PTT, which circumvents the limitations of conventional PTT (e.g., thermoresistance and adverse effects), is emerging and shows great potential in the forthcoming clinical applications. However, mild‐temperature PTT without adjuvant therapy is not able to completely eradicate tumors because its therapeutic efficacy is dramatically impaired by its inferior heat intensity. As a result, strategies capable of enhancing the anticancer efficacy of mild‐temperature PTT are urgently necessitated, which mainly rely on on‐demand fabrication of functionalized nanoagents. In this review, the strategies of nanoagent‐promoted mild‐temperature PTT are highlighted. Furthermore, challenges and opportunities in this field are rationally proposed, and hopefully people can be encouraged by this promising anticancer therapy.
Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency
Authors: Peramaiah Karthik , Ramalingam Vinoth , Fu Hui‐Chun , Alsabban Merfat M. , Ahmad Rafia , Cavallo Luigi , Tung Vincent , Huang Kuo‐Wei , He Jr‐Hau 
Published: April 2021

AbstractThe photoelectrochemical (PEC) approach is attractive as a promising route for the nitrogen reduction reaction (NRR) toward ammonia (NH3) synthesis. However, the challenges in synergistic management of optical, electrical, and catalytic properties have limited the efficiency of PEC NRR devices. Herein, to enhance light‐harvesting, carrier separation/transport, and the catalytic reactions, a concept of decoupling light‐harvesting and electrocatalysis by employing a cascade n+np+‐Si photocathode is implemented. Such a decoupling design not only abolishes the parasitic light blocking but also concurrently improves the optical and electrical properties of the n+np+‐Si photocathode without compromising the efficiency. Experimental and density functional theory studies reveal that the porous architecture and N‐vacancies promote N2 adsorption of the Au/porous carbon nitride (PCN) catalyst. Impressively, an n+np+‐Si photocathode integrating the Au/PCN catalyst exhibits an outstanding PEC NRR performance with maximum Faradaic efficiency (FE) of 61.8% and NH3 production yield of 13.8 µg h–1 cm–2 at −0.10 V versus reversible hydrogen electrode (RHE), which is the highest FE at low applied potential ever reported for the PEC NRR.
Transition‐Metal‐Free Synthesis of Unsymmetrical Disulfides via Three‐Component Reaction of Thiosulfonates, Thiourea and Alkyl halides
Authors: Wang Dungai , He Quan , Shi Keqiang , Xiong Mingteng , Zhou Yifeng , Pan Yuanjiang 
Published: April 2021

AbstractA transition‐metal‐free approach to synthesize unsymmetrical disulfides is reported that relies on a K2CO3‐promoted one‐pot reaction of thiosulfonates, thiourea and alkyl halides under mild conditions. The protocol tolerates a wide range of substrates, leading to various types of unsymmetrical disulfides in moderate to excellent yields. More importantly, the late‐stage modification of natural products and drug molecules was also achieved.magnified image
Synthesis of N‐Fused Indolines via Copper (II)‐Catalyzed Dearomatizing Cyclization of Indoles
Authors: Zhang Jingyu , Xia Wei , Huda Saskia , Ward Jas S. , Rissanen Kari , Albrecht Markus 
Published: April 2021

AbstractHerein, a copper(II)‐catalyzed dearomative cyclization amination of N‐(2‐aminobenzoyl) indoles is presented. Under mild reaction conditions, the cyclization proceeds to afford tetracyclic indolines by forming a new C−N bond in good yields. The tetracyclic 5a,6‐dihydroindolo[2,1‐b]quinazolin‐12(5H)‐ones are obtained in good to excellent yields (up to 99% yield) by using trifluoromethanesulfonic acid (TfOH) mediated N−Ts bond cleavage. The obtained compounds could be easily functionalized by simple synthetic methods.magnified image
Recent Developments in the Cyclization of Alkynes and Nitrogen Compounds for the Synthesis of Indole Derivatives
Authors: Neto Jose S. S. , Zeni Gilson 
Published: April 2021

AbstractThis review is intended to highlight the most useful approaches for the synthesis of indole derivatives (azaindoles, carbazoles, carbolines, indazoles, 3H‐indoles, indolines, indolizines, isoindoles, and isoindolines), which were described by using transition‐metal catalyzed cyclization reactions of alkynes and nitrogen compounds. The methodologies carried out under metal‐free conditions will also be illustrated herein. This review will cover the data published mostly in the past decade.
Conformational and Substituent Effects on The Rehybridization of Boron in β‐Substituted Ethylboranes
Authors: Martins Francisco A. , Freitas Matheus P. 
Published: April 2021

AbstractThe chemistry of boron‐containing molecules pervades the study of biomolecules, new materials, organic synthesis, and beyond. In addition, the stereochemistry and rehybridization capability of boron in molecules influence the reactivity and selectivity of reactions. Therefore, conformational analysis and the study of substituent effects on the modulation of the sp2–sp3 character of boron in β‐substituted ethylboranes may be valuable for the rational design of compounds in which the empty pB orbital plays a central role in the reaction intermediate. Accordingly, we have quantum‐chemically studied the orbital interactions and bonding properties that govern the conformational behavior and boron hybridization in β‐substituted ethylboranes (substituents, X=H, CH3, F, Cl, NH2, PH2, OH, and SH). Conformations with an anti arrangement along the B−C−C−X path are generally preferred over syn and/or gauche conformations, while a B−H bond tends to eclipse with the C−C bond rather than with a less sterically hindered C−H bond. However, the s character of boron relative to the C−B bond strongly decreases in the syn conformation, where X can participate as an electron donor to the empty pB orbital. Indeed, such interaction makes the syn conformation of 2‐aminoethylborane the single stable conformer in the gas phase.
Midlife vascular risk factors and risk of incident dementia: Longitudinal cohort and Mendelian randomization analyses in the UK Biobank
Authors: Malik Rainer , Georgakis Marios K. , Neitzel Julia , Rannikmäe Kristiina , Ewers Michael , Seshadri Sudha , Sudlow Cathie L.M. , Dichgans Martin 
Published: April 2021

AbstractIntroductionMidlife clustering of vascular risk factors has been associated with late‐life dementia, but causal effects of individual biological and lifestyle factors remain largely unknown.MethodsAmong 229,976 individuals (mean follow‐up 9 years), we explored whether midlife cardiovascular health measured by Life's Simple 7 (LS7) is associated with incident all‐cause dementia and whether the individual components of the score are causally associated with dementia.ResultsAdherence to the biological metrics of LS7 (blood pressure, cholesterol, glycemic status) was associated with lower incident dementia risk (hazard ratio = 0.93 per 1‐point increase, 95% confidence interval [CI; 0.89–0.96]). In contrast, there was no association between the composite LS7 score and the lifestyle subscore (smoking, body mass index, diet, physical activity) and incident dementia. In Mendelian randomization analyses, genetically elevated blood pressure was associated with higher risk of dementia (odds ratio = 1.31 per one‐standard deviation increase, 95% CI [1.05–1.60]).DiscussionThese findings underscore the importance of blood pressure control in midlife to mitigate dementia risk.
Na⋅⋅⋅B Bond in NaBH3−: Solving the Conundrum
Authors: Radenković Slavko , Shaik Sason S. , Braïda Benoît 
Published: April 2021

AbstractBonding in the recently synthesized NaBH3− cluster is investigated using the high level Valence Bond BOVB method. Contrary to earlier conclusions, the Na−B bond is found to be neither a genuine dative bond, nor a standard polar‐covalent bond at equilibrium. It is rather revealed as a split and polarized weakly coupled electron‐pair, which allows this cluster to be more effectively stabilized by a combination of (major) dipole‐dipole electrostatic interaction and (secondary) resonant one‐electron bonding mechanism. Our analysis of this unprecedented bonding situation extends to similar clusters, and the VB model unifies and articulates the previously published variegated views on this exotic “bond”.
Implications of Quenching‐to‐Dequenching Switch in Quantitative Cell Uptake and Biodistribution of Dye‐Labeled Nanoparticles
Authors: Yang Guangze , Liu Yun , Hui Yue , Tengjisi  , Chen Dong , Weitz David A. , Zhao Chun‐Xia 
Published: April 2021

AbstractA general strategy to carry out cell uptake and biodistribution studies is to label nanoparticles (NPs) with a fluorescent dye. However, the comparative study of different dye‐loaded NPs remains difficult owing to uncontrolled dye quenching and de‐quenching. Here we compared two types of dye‐labeled NPs and demonstrated their distinct properties. NPs with dye molecules at a solid state suffer from dye quenching, so the dye release and/or NP degradation in biological environments leads to a several‐fold increase of fluorescence intensity despite the same amount of NPs, owing to the state switch from quenching to de‐quenching. In contrast, NPs with dye molecules at a soluble state exhibit no quenching effect. To standardize the comparative study, we propose two possible solutions: using lower dye loading or using medium analysis for quantifying cell uptake of NPs. This work provides valuable insights into selecting valid quantification methods for bio‐nano studies.
Freezing‐Assisted Conjugation of Unmodified Diblock DNA to Hydrogel Nanoparticles and Monoliths for DNA and Hg2+ Sensing
Authors: Li Yuqing , Gao Hang , Qi Zengyao , Huang Zhicheng , Ma Lingzi , Liu Juewen 
Published: April 2021

AbstractAcrydite‐modified DNA is the most frequently used reagent to prepare DNA‐functionalized hydrogels. Herein, we show that unmodified penta‐adenine (A5) can reach up to 75 % conjugation efficiency in 8 h under a freezing polymerization condition in polyacrylamide hydrogels. DNA incorporation efficiency was reduced by forming duplex or other folded structures and by removing the freezing condition. By designing diblock DNA containing an A5 block, various functional DNA sequences were attached. Such hydrogels were designed for ultrasensitive DNA hybridization and Hg2+ detection, with detection limits of 50 pM and 10 nM, respectively, demonstrating the feasibility of using unmodified DNA to replace acrydite‐DNA. The same method worked for both gel nanoparticles and monoliths. This work revealed interesting reaction products by exploiting freezing and has provided a cost‐effective way to attach DNA to hydrogels.
Triptycene‐based Chiral Porous Polyimides for Enantioselective Membrane Separation
Authors: Zhang Qing‐Pu , Wang Zhen , Zhang Zhe‐Wen , Zhai Tian‐Long , Chen Jing‐Jing , Ma Hui , Tan Bien , Zhang Chun 
Published: April 2021

AbstractEnantiomers of 2, 6‐diaminotriptycene (R, R‐1 and S, S‐1) are split by chiral‐phase HPLC and their absolute configurations are identified by single‐crystal X‐ray diffraction technology. Using the enantiomers as monomers, a couple of chiral porous polyimides (R‐FTPI and S‐FTPI) are prepared by polycondensation reactions and display good heat stability, high BET surface area and good solubility in organic solvents. Moreover, both of R‐FTPI and S‐FTPI can be cast into robust, free‐standing films suitable for enantioselective separation with symmetrical chiral selectivity.
Efficient (>20 %) and Stable All‐Inorganic Cesium Lead Triiodide Solar Cell Enabled by Thiocyanate Molten Salts
Authors: Yu Bingcheng , Shi Jiangjian , Tan Shan , Cui Yuqi , Zhao Wenyan , Wu Huijue , Luo Yanhong , Li Dongmei , Meng Qingbo 
Published: April 2021

AbstractBesides widely used surface passivation, engineering the film crystallization is an important and more fundamental route to improve the performance of all‐inorganic perovskite solar cells. Herein, we have developed a urea‐ammonium thiocyanate (UAT) molten salt modification strategy to fully release and exploit coordination activities of SCN− to deposit high‐quality CsPbI3 film for efficient and stable all‐inorganic solar cells. The UAT is derived by the hydrogen bond interactions between urea and NH4+ from NH4SCN. With the UAT, the crystal quality of the CsPbI3 film has been significantly improved and a long single‐exponential charge recombination lifetime of over 30 ns has been achieved. With these benefits, the cell efficiency has been promoted to over 20 % (steady‐state efficiency of 19.2 %) with excellent operational stability over 1000 h. These results demonstrate a promising development route of the CsPbI3 related photoelectric devices.
Bioinspired Color Switchable Photonic Crystal Silicone Elastomer Kirigami
Authors: Lai Xintao , Peng Jingsong , Cheng Qunfeng , Tomsia Antoni P. , Zhao Guanlei , Liu Lei , Zou Guisheng , Song Yanlin , Jiang Lei , Li Mingzhu 
Published: April 2021

AbstractBioinspired dynamic structural color has great potential for use in dynamic displays, sensors, cryptography, and camouflage. However, it is quite rare for artificial structural color devices to withstand thousands of cycles. Male hummingbird's crowns and gorgets are brightly colored, demonstrating frequent color switching that is induced by regulating the orientation of the feathers through movement of skin or joints. Inspired by this unique structural color modulation, we demonstrate a flexible, mechanically triggered color switchable sheet based on a photonic crystal (PhC)‐coated polydimethylsiloxane (PDMS) kirigami (PhC‐PDMS kirigami) made by laser cutting. Finite element modeling (FEM) simulation reveals that the thickness of PDMS kirigami and the chamfer at the incision induced by laser cutting both dominate the out‐of‐plane deformation through in‐plane stretching. The bioinspired PhC‐PDMS kirigami shows precisely programmable structural color and keeps the color very well after recycling over 10 000 times. This bioinspired PhC‐PDMS kirigami also shows excellent viewability even in bright sunlight, high readability, robust functionality, technical flexibility, and mechanical durability, which are readily exploitable for applications, such as chromic mechanical monitors for the sports industry or for medical applications, wearable camouflage, and security systems.
Direct Synthesis of Ketones from Methyl Esters by Nickel‐Catalyzed Suzuki–Miyaura Coupling
Authors: Zheng Yan‐Long , Xie Pei‐Pei , Daneshfar Omid , Houk Kendall N. , Hong Xin , Newman Stephen G. 
Published: April 2021

AbstractThe direct conversion of alkyl esters to ketones has been hindered by the sluggish reactivity of the starting materials and the susceptibility of the product towards subsequent nucleophilic attack. We have now achieved a cross‐coupling approach to this transformation using nickel, a bulky N‐heterocyclic carbene ligand, and alkyl organoboron coupling partners. 65 alkyl ketones bearing diverse functional groups and heterocyclic scaffolds have been synthesized with this method. Catalyst‐controlled chemoselectivity is observed for C(acyl)−O bond activation of multi‐functional substrates bearing other bonds prone to cleavage by Ni, including aryl ether, aryl fluoride, and N‐Ph amide functional groups. Density functional theory calculations provide mechanistic support for a Ni0/NiII catalytic cycle and demonstrate how stabilizing non‐covalent interactions between the bulky catalyst and substrate are critical for the reaction's success.
Ratiometric Fluorescent Lateral Flow Immunoassay for Point‐of‐Care Testing of Acute Myocardial Infarction
Authors: Wang Jing , Jiang Chenxing , Jin Jiening , Huang Liang , Yu Wenbo , Su Bin , Hu Jun 
Published: April 2021

AbstractWe report the development of a highly sensitive ratiometric fluorescent lateral flow immunoassay (RFLFIA) strip for rapid and accurate detection of acute myocardial infarction biomarker, namely heart‐type fatty acid binding protein (H‐FABP). The RFLFIA strip works in terms of ratiometric change of fluorescence signal, arising from blending of fluorescence emitted by two composite nanostructures conjugated to capture and probe antibodies and inner filter effect of gold nanoparticles. In conjunction with using custom smartphone‐based analytical device and tonality analysis, quantitative detection of H‐FABP was achieved with a low limit of detection at 0.21 ng mL−1. The RFLFIA strip can generate a visually distinguishable green‐to‐red color change around the threshold concentration of H‐FABP (6.2 ng mL−1), thus allowing the semi‐quantitative diagnosis by the naked eye.
Kinetic Microscale Thermophoresis for Simultaneous Measurement of Binding Affinity and Kinetics
Authors: Stein Julian A. C. , Ianeselli Alan , Braun Dieter 
Published: April 2021

AbstractMicroscale thermophoresis (MST) is a versatile technique to measure binding affinities of binder–ligand systems, based on the directional movement of molecules in a temperature gradient. We extended MST to measure binding kinetics as well as binding affinity in a single experiment by increasing the thermal dissipation of the sample. The kinetic relaxation fingerprints were derived from the fluorescence changes during thermodynamic re‐equilibration of the sample after local heating. Using this method, we measured DNA hybridization on‐rates and off‐rates in the range 104–106 m−1 s−1 and 10−4–10−1 s−1, respectively. We observed the expected exponential dependence of the DNA hybridization off‐rates on salt concentration, strand length and inverse temperature. The measured on‐rates showed a linear dependence on salt concentration and weak dependence on strand length and temperature. For biomolecular interactions with large enthalpic contributions, the kinetic MST technique offers a robust, cost‐effective and immobilization‐free determination of kinetic rates and binding affinity simultaneously, even in crowded solutions.
Nickel‐Catalyzed Asymmetric Reductive Carbo‐Carboxylation of Alkenes with CO2
Authors: Chen Xiao‐Wang , Yue Jun‐Ping , Wang Kuai , Gui Yong‐Yuan , Niu Ya‐Nan , Liu Jie , Ran Chuan‐Kun , Kong Wangqing , Zhou Wen‐Jun , Yu Da‐Gang 
Published: April 2021

AbstractReductive carboxylation of organo (pseudo)halides with CO2 is a powerful method to provide carboxylic acids quickly. Notably, the catalytic reductive carbo‐carboxylation of unsaturated hydrocarbons via CO2 fixation is a highly challenging but desirable approach for structurally diverse carboxylic acids. There are only a few reports and no examples of alkenes via transition metal catalysis. We report the first asymmetric reductive carbo‐carboxylation of alkenes with CO2 via nickel catalysis. A variety of aryl (pseudo)halides, such as aryl bromides, aryl triflates and inert aryl chlorides of particular note, undergo the reaction smoothly to give important oxindole‐3‐acetic acid derivatives bearing a C3‐quaternary stereocenter. This transformation features mild reaction conditions, wide substrate scope, facile scalability, good to excellent chemo‐, regio‐ and enantioselectivities. The method highlights the formal synthesis of (−)‐Esermethole, (−)‐Physostigmine and (−)‐Physovenine, and the total synthesis of (−)‐Debromoflustramide B, (−)‐Debromoflustramine B and (+)‐Coixspirolactam A; thereby, opening an avenue for the total synthesis of chiral natural products with CO2.
Total Synthesis of the Spliceosome Modulator Pladienolide B via Asymmetric Alcohol‐Mediated syn‐ and anti‐Diastereoselective Carbonyl Crotylation
Authors: Yoo Minjin , Krische Michael J. 
Published: April 2021

AbstractThe potent spliceosome modulator pladienolide B, which bears 10 stereogenic centers, is prepared in 10 steps (LLS). Asymmetric alcohol‐mediated carbonyl crotylations catalyzed by ruthenium and iridium that occur with syn‐ and anti‐diastereoselectivity, respectively, were used to form the C20‐C21 and C10‐C11 C−C bonds.
Redefining Net‐Zero Water for Resilient Aquifers
Authors: Yonkofski Catherine , Tartakovsky Guzel , Feng Youcan , Loper Susan , Yoder Tim , Solana Amy 
Published: April 2021

Key TakeawaysNet‐zero water for long‐term water security and sustainability can be best quantified by comparing consumption with the net freshwater balance, including source water recharge.This approach can support individual decisions when investing in water infrastructure and water conservation projects or for identifying critical locations for aquifer recharge.While the sites studied did not meet US Army's Net Zero water criteria using the traditional calculation, all achieved or have feasible plans to achieve Net Zero under this more holistic approach.