bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Reductive Coupling of Vinyl Azaarenes and Alkynes via Photoredox Cobalt Dual Catalysis
Authors: Gu Zheng‐Yang , Li Wen‐Duo , Li Yan‐Lin , Cui Kun , Xia Ji‐Bao 
Published: September 2022

AbstractA visible light‐induced Co‐catalyzed highly regio‐ and stereoselective reductive coupling of vinyl azaarenes and alkynes has been developed. Notably, Hünig's base together with simple ethanol has been successfully applied as the hydrogen sources instead of commonly used Hantzsch esters in this catalytic photoredox reaction. This approach has considerable advantages for the straightforward synthesis of stereodefined multiple substituted alkenes bearing an azaarene motif, such as excellent regioselectivity (>20 : 1 for >30 examples) and stereoselectivity (>20 : 1 E/Z), broad substrate scope and good functional group compatibility under mild reaction conditions, which has been utilized in the concise synthesis of natural product monomorine I. A reasonable catalytic reaction pathway involving protolysis of the cobaltacyclopentene intermediate has been proposed based on the mechanistic studies.
Thermoreversible Polymorph Transitions in Supramolecular Polymers of Hydrogen‐Bonded Squaramides
Authors: Bujosa Sergi , Doncel‐Giménez Azahara , Bäumer Nils , Fernández Gustavo , Ortí Enrique , Costa Antonio , Rotger Carmen , Aragó Juan , Soberats Bartolome 
Published: September 2022

AbstractHydrogen‐bonded squaramide (SQ) supramolecular polymers exhibit uncommon thermoreversible polymorph transitions between particle‐ and fiber‐like nanostructures. SQs1–3, with different steric bulk, self‐assemble in solution into particles (AggI) upon cooling to 298 K, and SQs1and2, with only one dendronic group, show a reversible transformation into fibers (AggII) by further decreasing the temperature to 288 K. Nano‐DSC and UV/Vis studies on SQ1reveal a concentration‐dependent transition temperature and ΔHfor theAggI‐to‐AggIIconversion, while the kinetic studies on SQ2indicate the on‐pathway nature of the polymorph transition. Spectroscopic and theoretical studies reveal that these transitions are triggered by the molecular reorganization of the SQ units changing from slipped to head‐to‐tail hydrogen bonding patterns. This work unveils the thermodynamic and kinetic aspects of reversible polymorph transitions that are of interest to develop stimuli‐responsive systems.
A Deep‐Learning Framework for the Automated Recognition of Molecules in Scanning‐Probe‐Microscopy Images
Authors: Zhu Zhiwen , Lu Jiayi , Zheng Fengru , Chen Cheng , Lv Yang , Jiang Hao , Yan Yuyi , Narita Akimitsu , Müllen Klaus , Wang Xiao‐Ye , Sun Qiang 
Published: September 2022

AbstractComputer vision as a subcategory of deep learning tackles complex vision tasks by dealing with data of images. Molecular images with exceptionally high resolution have been achieved thanks to the development of techniques like scanning probe microscopy (SPM). However, extracting useful information from SPM image data requires careful analysis which heavily relies on human supervision. In this work, we develop a deep learning framework using an advanced computer vision algorithm, Mask R‐CNN, to address the challenge of molecule detection, classification and instance segmentation in binary molecular nanostructures. We employ the framework to determine two triangular‐shaped molecules of similar STM appearance. Our framework could accurately differentiate two molecules and label their positions. We foresee that the application of computer vision in SPM images will become an indispensable part in the field, accelerating data mining and the discovery of new materials.
Self‐Propelled Magnetic Dendrite‐Shaped Microrobots for Photodynamic Prostate Cancer Therapy
Authors: Peng Xia , Urso Mario , Balvan Jan , Masarik Michal , Pumera Martin 
Published: September 2022

AbstractPhotocatalytic micromotors that exhibit wireless and controllable motion by light have been extensively explored for cancer treatment by photodynamic therapy (PDT). However, overexpressed glutathione (GSH) in the tumor microenvironment can down‐regulate the reactive oxygen species (ROS) level for cancer therapy. Herein, we present dendrite‐shaped light‐powered hematite microrobots as an effective GSH depletion agent for PDT of prostate cancer cells. These hematite microrobots can display negative phototactic motion under light irradiation and flexible actuation in a defined path controlled by an external magnetic field. Non‐contact transportation of micro‐sized cells can be achieved by manipulating the microrobot's motion. In addition, the biocompatible microrobots induce GSH depletion and greatly enhance PDT performance. The proposed dendrite‐shaped hematite microrobots contribute to developing dual light/magnetic field‐powered micromachines for the biomedical field.
Unexpected Persistent Production of Reactive Oxygen Species during the Degradation of Black Phosphorous in the Darkness
Authors: Yu Wanchao , Xu Jin , Chen Fengjie , Wang Yarui , Tang Shanshan , Geng Fanglan , Lv Jitao , Qu Guangbo , Zhao Lixia , Wang Yawei 
Published: September 2022

AbstractFew‐layer black phosphorus (FLBP) is easily degraded under ambient conditions which is problem that hinders the application of FLBP, but its degradation mechanism is not yet well understood. In this work, we surprisingly found that persistent generation of reactive oxygen species (ROS) was involved in FLBP degradation even in the dark. The ROS generation patterns and mechanism were revealed by chemiluminescence (CL) and density functional theory (DFT). Meanwhile, rhodamine B (RhB) and methyl orange (MO) can also be removed by FLBP under dark conditions, which further shows the ROS generation during FLBP self‐degradation. This work provides new insights into the FLBP self‐degradation mechanism and opens opportunities to practically implement FLBP for green catalytic application.
Photochemical Mechanisms of Fluorophores Employed in Single‐Molecule Localization Microscopy
Authors: Kikuchi Kai , Adair Liam D. , Lin Jiarun , New Elizabeth J. , Kaur Amandeep 
Published: September 2022

AbstractDecoding cellular processes requires visualization of the spatial distribution and dynamic interactions of biomolecules. It is therefore not surprising that innovations in imaging technologies have facilitated advances in biomedical research. The advent of super‐resolution imaging technologies has empowered biomedical researchers with the ability to answer long‐standing questions about cellular processes at an entirely new level. Fluorescent probes greatly enhance the specificity and resolution of super‐resolution imaging experiments. Here, we introduce key super‐resolution imaging technologies, with a brief discussion on single‐molecule localization microscopy (SMLM). We evaluate the chemistry and photochemical mechanisms of fluorescent probes employed in SMLM. This Review provides guidance on the identification and adoption of fluorescent probes in single molecule localization microscopy to inspire the design of next‐generation fluorescent probes amenable to single‐molecule imaging.
Block Poly(carbonate‐ester) Ionomers as High‐Performance and Recyclable Thermoplastic Elastomers
Authors: Gregory Georgina L. , Sulley Gregory S. , Kimpel Joost , Łagodzińska Matylda , Häfele Lisa , Carrodeguas Leticia Peña , Williams Charlotte K. 
Published: September 2022

AbstractThermoplastic elastomers based on polyesters/carbonates have the potential to maximize recyclability, degradability and renewable resource use. However, they often underperform and suffer from the familiar trade‐off between strength and extensibility. Herein, we report well‐defined reprocessable poly(ester‐b‐carbonate‐b‐ester) elastomers with impressive tensile strengths (60 MPa), elasticity (>800 %) and recovery (95 %). Plus, the ester/carbonate linkages are fully degradable and enable chemical recycling. The superior performances are attributed to three features: (1) Highly entangled soft segments; (2) Fully reversible strain‐induced crystallization and (3) Precisely placed ZnII‐carboxylates dynamically crosslinking the hard domains. The one‐pot synthesis couples controlled cyclic monomer ring‐opening polymerization and alternating epoxide/anhydride ring‐opening copolymerization. Efficient convresion to ionomers is achieved by reacting vinyl‐epoxides to install ZnII‐carboxylates.
Improved Charge Separation in Poly(heptazine‐triazine) Imides with Semi‐coherent Interfaces for Photocatalytic Hydrogen Evolution
Authors: Zhang Jian , Liang Xiaocong , Zhang Chao , Lin Lihua , Xing Wandong , Yu Zhiyang , Zhang Guigang , Wang Xinchen 
Published: September 2022

AbstractThe construction of heterojunctions is a promising manner to accelerate the separation and transfer of the charge carriers at the interface. Herein, a binary poly(heptazine‐triazine) imides (PHI/PTI) with semi‐coherent interfaces was fabricated via a facile two‐step salt‐melt synthetic process. The built‐in electric fields at the semi‐coherent interface endow prompt exciton splitting and charge carrier separation. Hence, the optimized PHI/PTI‐based copolymer presents a high apparent quantum yield (AQY=64 %) for visible‐light driven hydrogen production, by the aids of K2HPO4as charge transfer mediator. This study provides physical insights for the rational promotion of the photocatalytic performance from the viewpoint of interfacial engineering of photocatalytic junctions on crystalline carbon nitride based semiconductors.
Double‐pronged Antimicrobial Agents based on a Donor‐π‐Acceptor Type Aggregation‐Induced Emission Luminogen
Authors: Wu Yifan , Li Jiangao , Shen Zipeng , Wang Deliang , Dong Ruihua , Zhang Jiangjiang , Pan Yinzhen , Li Ying , Wang Dong , Tang Ben Zhong 
Published: September 2022

AbstractNovel antibacterial agents are urgently needed to control the infections induced by multidrug‐resistant (MDR) bacteria. Herein, we rationally designed and facilely synthesized a new D‐π‐A type luminogen with strong red/near‐infrared fluorescence emission, great aggregation‐induced emission (AIE) features, and excellent reactive oxygen species (ROS) production. The newly developed molecule TTTh killed the methicillin‐resistant Staphylococcus aureus (MRSA) by triggering the ROS accumulation in bacteria and interrupting the membrane integrity. Moreover, TTTh specifically targeted the lysosomes and potentiated their maturation to accelerate the clearance of intracellular bacteria. Additionally, reduced bacterial burden and improved healing were observed in TTTh‐treated wounds with negligible side effects. Our study expands the biological design and application of AIE luminogens (AIEgens), and provides new insights into discovering novel antibacterial targets and agents.
Linear Axially Chiral Conjugated Polymers Exhibiting Ultralong Low‐Temperature Phosphorescence and Intense Circularly Polarized Luminescence
Authors: Zhang Da‐Wei , Li Meng , Chen Chuan‐Feng 
Published: September 2022

AbstractUltralong organic phosphorescence (UOP) and circularly polarized luminescence (CPL), as two important branches in the field of organic optical functional materials have broad prospects. In this work, a pair of novel conjugated polymers with low‐temperature UOP and intense CPL properties are constructed by incorporating rigid axially chiral chromophores into a polymeric backbone. The twisted and rigid biphenyl skeleton not only effectively reduces the energy gap between the S1and T to greatly facilitate the intersystem crossing process, but also suppress the non‐radiative decay from T1to S0. As a result, a strong and ultralong afterglow of up to 33 s is achieved in 2‐MeTHF at 77 K. Moreover, the repeating rigid biphenyl skeleton with its helix‐like form also promotes the chiroptical activity of the polymers, and intense signals are shown in the low‐temperature CPL spectra with absoluteglumvalues of 9.7×10−3and 5.8×10−3at the fluorescence and phosphorescence emission peaks, respectively. This work represents the first low‐temperature materials with UOP and CPL properties, which provides a new guideline and perspective for the development of persistent luminescence materials.
Late‐Stage Modification of Oligopeptides by Nickel‐Catalyzed Stereoselective Radical Addition to Dehydroalanine
Authors: Qi Xiaoxu , Jambu Subramanian , Ji Yining , Belyk Kevin M. , Panigrahi Nihar R. , Arora Paramjit S. , Strotman Neil A. , Diao Tianning 
Published: September 2022

AbstractRadical addition to dehydroalanine (Dha) represents an appealing, modular strategy to access non‐canonical peptide analogues for drug discovery. Prior studies on radical addition to the Dha residue of peptides and proteins have demonstrated outstanding functional group compatibility, but the lack of stereoselectivity has limited the synthetic utility of this approach. Herein, we address this challenge by employing chiral nickel catalysts to control the stereoselectivity of radical addition to Dha on oligopeptides. The conditions accommodate a variety of primary and secondary electrophiles to introduce polyethylene glycol, biotin, halo‐tag, and hydrophobic and hydrophilic side chains to the peptide. The reaction features catalyst control to largely override substrate‐based control of stereochemical outcome for modification of short peptides. We anticipate that the discovery of chiral nickel complexes that confer catalyst control will allow rapid, late‐stage modification of peptides featuring nonnatural sidechains.
Iridium‐Catalyzed Asymmetric Allylic Benzylation with Photogenerated Hydroxy‐o‐Quinodimethanes
Authors: Yang Pusu , Wang Rui‐Xiang , Cheng Yuan‐Zheng , Zheng Chao , You Shu‐Li 
Published: September 2022

AbstractAn iridium‐catalyzed asymmetric allylic benzylation of aryl vinyl carbinols under light irradiation is described. 2‐Methylbenzophenone derivatives are employed and activated to hydroxy‐o‐quinodimethanes by an ultraviolet (UV) light. This approach enables asymmetric allylic benzylation with high enantioselectivity (up to 99 % ee) from readily available 2‐methylbenzophenones without the utilization of strong bases, and pre‐activation or pre‐functionalization of the substrates. Moreover, deuterium experiments reveal the generation of nucleophilic benzyl species from 2‐methylbenzophenone under UV irradiation.
Pyrogallate‐Based Metal‐Organic Framework with a Two‐Dimensional Secondary Building Unit
Authors: Kampouri Stavroula , Zhang Mingxuan , Chen Tianyang , Oppenheim Julius J. , Brown Alexandra C. , Payne Michael T. , Andrews Justin L. , Sun Junliang , Dincă Mircea 
Published: September 2022

AbstractWe report a metal–organic framework (MOF) with a rare two‐dimensional (2D) secondary building unit (SBU). The SBU comprises mixed‐valent Fe2+ and Fe3+ metal ions bridged by oxygen atoms pertaining to the polytopic ligand 3,3′,4,4′,5,5′‐hexahydroxybiphenyl, which also define the iron‐oxide 2D layers. Overall, the anionic framework exhibits rare topology and evidences strong electronic communication between the mixed‐valence iron sites. These results highlight the importance of dimensionality control of MOF SBUs for discovering new topologies in reticular chemistry, and especially for improving electronic communication within the MOF skeleton.
Lightning strike damage resistance of carbon‐fiber composites with nanocarbon‐modified epoxy matrices
Authors: Kopsidas Sotirios , Olowojoba Ganiu B. , Stone Chris , Clark David , Haddad A. Manu , Kinloch Anthony J. , Taylor Ambrose C. 
Published: September 2022

AbstractCarbon‐fiber reinforced polymer (CFRP) composites are replacing metal alloys in aerospace structures, but they can be vulnerable to lightning strike damage if not adequately protected due to the poor electrical conductivity of the polymeric matrix. In the present work, to improve the conductivity of the CFRP, two electrically conductive epoxy formulations were developed via the addition of 0.5 wt% of graphene nanoplatelets (GNPs) and a hybrid of 0.5 wt% of GNPs/carbon nanotubes (CNTs) at an 8:2 mass ratio. Unidirectional CFRP laminates were manufactured using resin‐infusion under flexible tooling (RIFT) and wet lay‐up (WL) processes, and subjected to simulated lightning strike tests. The electrical performance of the RIFT plates was far superior to that of the WL plates, independent of matrix modification, due to their greater carbon‐fiber volume fraction. The GNP‐modified panel made using RIFT demonstrated an electrical conductivity value of 8 S/cm. After the lightning strike test, the CFRP panel remains largely unaffected as no perforation occurs. Damage is limited to matrix degradation within the top ply at the point of impact and localized charring of the surface. The GNP‐modified panel showed a comparable level of resistance against lightning damage with the existing copper mesh technology, offering at the same time a 20% reduction in the structural weight. This indicates a feasible route to improve the lightning strike damage resistance of carbon‐fiber composites without the addition of extra weight, hence reducing fuel consumption but not safety.
Mechanical characteristics of high strength concrete incorporating recycled CFRP fibers
Authors: Lamba Nitin , Raj Ritu , Singh Poonam 
Published: September 2022

AbstractThe current research article assesses the feasibility of recycled CFRP (Carbon‐Fiber‐ Reinforced‐Polymer) fibers in high‐strength concrete. Different dosages of recycled CFRP fibers (0.2%, 0.4%, 0.6%, 0.8%, and 1%) as well as different aspect ratios of CFRP fibers with 10 and 20 mm fiber lengths is assessed for hardened state characteristics of reinforced high‐strength concrete. Furthermore, ultrasonic pulse velocity test, compression test, flexure test, and impact resistance test are performed to understand the hardened properties of specimens. The chemical composition of various elements present in the various kinds of concrete samples is qualitatively and quantitatively found with the help of energy‐dispersive X‐ray spectroscopy (EDX) equipment. To understand the surface morphology of carbon fibers incorporated in concrete samples, Scanning electron microscope (SEM) photographs are obtained to examine the prepared samples thoroughly. Linear regression analysis, an analytical analysis technique, is incorporated to linearly correlate the different hardened mechanical characteristics of specimens taking into account varying lengths and different dosages of recycled CFRP fiber. The findings reveal that increasing the CFRP fiber dosage and the aspect ratio of recycled CFRP fiber improves the reinforced mix composition's mechanical characteristics.
Tension responses of carbon black filled rubbers at intermediate and high strain rates: Experimental investigation and modeling
Authors: Liu Min , Li Ziran , Wang Yang 
Published: September 2022

AbstractThe uniaxial tensile stress – strain responses of carbon black filled rubbers were experimentally investigated at various strain rates of 0.001, 0.05, 2.5 and 400 s−1. A conventional hydraulically driven material testing system, an intermediate strain‐rate testing system and a split‐Hopkinson tension bar were respectively utilized to carry out the monotonic tensile loadings at quasi‐static, intermediate and high strain rates. A complete experimental strategy for intermediate strain‐rate testing of rubber‐like materials with low modulus and low strength was proposed including constant strain‐rate loading, sample clamping and dynamic force measuring methods. The experimentally obtained engineering stress ‐ strain results show that the tensile properties of carbon black filled rubbers are highly nonlinear and rate‐dependent. A visco‐hyperelastic constitutive model based on the modified eight‐chain model parallel with three linear Maxwell elements was developed to describe the tensile responses of carbon black filled rubbers. Especially, the relationship between the number of Maxwell elements used in the model and the tested strain rate range was discussed.
Preparation of a composite hydrogel of polyvinyl alcohol/chitosan fiber with anisotropic properties for sustained drug release
Authors: Huang Jing , Wu Danpin , Xiong Xiaopeng 
Published: September 2022

AbstractHydrogel with anisotropic properties has promising potentials, while its fabrication is still challenging. In this work, chitosan fiber (CF) was designed to reinforce polyvinyl alcohol (PVA) hydrogel anisotropically. First, CF was pre‐treated in a weak acidic buffer to create rough surface as well as outward‐stretched chitosan chain end segments, and then mixed with PVA in solution. A PVA/CFs composite hydrogel was thereafter prepared by casting the mixture with a pushing force followed by freeze‐thawing cycles. The microstructure of the composite hydrogel was characterized by scanning electron microscopy, optical microscopy and Fourier transform infrared spectroscopy, and its mechanical properties at the directions parallel to and perpendicular to the casting force were measured. Our results indicate that the pre‐treated CF can reinforce the PVA hydrogel effectively, especially along the casting force direction. The tensile strength, breaking elongation and toughness of the composite hydrogel with only 0.2% CFs at the parallel direction reach 175%, 117% and 244% those of the PVA hydrogel, respectively. The anisotropic reinforcement effect has been understood by the orientating of CFs and the interfacial bonding between the CFs and the PVA matrix. Moreover, bovine serum albumin was released sustainably from the anisotropic hydrogel to indicate its potential application.
Protective Activities of Scutellarin against Alcohol‐Induced Acute Kidney Injury
Authors: Yang Qiankun , Wang Yan , Chen Huizhen , Fan Hui , Zhang Xiao , Bello Babatunde Kazeem , Liu Gang , Feng Xin , Teng Daoyang , Chen Yi , Zhao Panpan , Dong Jingquan 
Published: September 2022

AbstractAcute alcohol consumption has adverse effects in the kidney, resulting in kidney damage and disease, which are typically accompanied by oxidation and inflammation. Scutellarin (SCU) is the major effective ingredient of breviscapine and its anti‐inflammation and antioxidant efficacy has been previously reported. The present study revealed the protective effective of SCU as therapeutic medicine against alcohol‐induced inflammation and oxidative stress, leading to acute kidney injury (AKI). The AKI model was established by giving 50 % ethanol (12 mL/kg) via lavage. Kidney tissues were collected and used for histopathology analysis, biochemical assays and qRT‐PCR analysis. The therapeutic effects of SCU were evaluated by observing pathological changes from HE‐stained kidney tissues. Additionally, the anti‐inflammation activity of SCU was evaluated by measuring the relative mRNA expression levels of Tnf‐α, Il‐1β, Il‐6 and the activity of iNOS. The antioxidant capacity was assessed by measuring the lipid peroxidation marker ‘MDA’ and antioxidant enzymes activity of SOD, CAT and GSH‐Px. The results showed that serious swelling and damage occurred in the renal tubular epithelium of alcohol intake group, accompanying with glomerular atrophy, necrosis and increase of inflammatory infiltration. SCU treatment significantly reduced the damage of diseased renal tubular epithelium and glomerular, and less inflammatory cell emerged. The inflammation cytokines expression levels were elevated and oxidative stress index decreased after alcohol intake compared to the control group. In conclusion, inflammation and oxidative stress occur in the kidney after acute and excessive alcohol intake, SCU exhibited protective roles via its anti‐inflammation and antioxidant activity in AKI.