bluuebunny/crossref_metadata_2025_split huggingface dataset:
2,4,6‐Triphenyl‐1,3,5‐Triazine Based Covalent Organic Frameworks for Photoelectrochemical H2 Evolution
Authors: Dai Chunhui , He Ting , Zhong Lixiang , Liu Xingang , Zhen Wenlong , Xue Can , Li Shuzhou , Jiang Donglin , Liu Bin 
Published: February 2021

AbstractPhotoelectrochemical water splitting over semiconductors offers a sustainable solar light conversion technique capable of alleviating worldwide energy crisis. Conjugated polymers have recently received increasing attention as a class of promising photoelectrode materials due to their advantages of earth‐abundance, non‐toxicity, light weight, and molecularly tunable functionalities, etc. However, the development of highly efficient organic photoelectrodes remains a big challenge. In this study, two covalent organic frameworks (COFs) incorporated 2,4,6‐triphenyl‐1,3,5‐triazine are demonstrated as excellent photocathodes for H2 production. By introducing 2,4,6‐triphenylbenene to properly create donor/acceptor pairs within COF, a significantly enhanced visible‐light photocurrent of TAPB‐TTB COF (110 µA cm−2) compared to TTA‐TTB COF (35 µA cm−2) at 0 V versus reversible hydrogen electrode (RHE) is obtained without adding organic sacrificial agent and metal cocatalysts (>420 nm). The enhanced photocurrent density is attributed to the narrowed bandgap and improved charge transfer by intramolecular donor–acceptor combination. This work highlights the great promising applications of crystalline donor–acceptor COFs as high‐efficiency organic photoelectrode for water splitting.
Acoustic Metamaterials: A Review of Theories, Structures, Fabrication Approaches, and Applications
Authors: Liao Guangxin , Luan Congcong , Wang Zhenwei , Liu Jiapeng , Yao Xinhua , Fu Jianzhong 
Published: February 2021

AbstractAcoustic metamaterials (AMs), which are materials composed of subwavelength periodic artificial structures with specific designs, have drawn significant research attention. This is because of the extraordinary abilities of AMs to manipulate acoustic waves compared with those of traditional acoustic materials. In this review, current advances in AM research are comprehensively investigated and summarized. First, major theories regarding AMs, including the acoustic wave equation, crystal lattice and energy band theory, effective medium theory, and general Snell's law, are explained in detail. Existing AM structures are then described and divided into several categories based on their structural characteristics and responses to acoustic waves. Furthermore, to bridge the gap between design and practical application, both conventional and advanced AM manufacturing methods are summarized. The applications of AMs in the fields of acoustic cloaking, acoustic lensing, acoustic absorption, noise reduction, and supernormal sound transmission are particularly delineated. Finally, contemporary challenges, trends, and strategies relevant to AMs are discussed. This review aims to provide a comprehensive collection of AM‐related knowledge, including information regarding physical theories, structures, fabrication approaches, and applications, which will help promote the further development of AMs.
Efficient Semi‐Transparent Organic Solar Cells with High Color Rendering Index Enabled by Self‐Assembled and Knitted AgNPs/MWCNTs Transparent Top Electrode via Solution Process
Authors: Zhang Yuniu , He Xinjun , Babu Dickson , Li Wenhui , Gu Xiaoyu , Shan Chengwei , Kyaw Aung Ko Ko , Choy Wallace C. H. 
Published: February 2021

AbstractSemi‐transparent organic solar cells (STOSCs) have attracted tremendous attention in power‐generating windows for buildings and automobiles. Although STOSCs based on vacuum‐deposited thin metal films exhibited power conversion efficiency exceeding 10%, solution‐processed top transparent electrode (TE) is desirable for large‐area and low‐cost fabrication of STOSCs. Here, we present a self‐assembled and knitted Ag nanoparticles/multi‐walled carbon nanotubes composite thin film by solution process as transparent top electrode for STOSC. The composite film exhibits an extremely low sheet resistance of 14.5Ω sq−1, an average visible transmittance (AVT) of ≈67%, and a high color rendering index (CRI) of 97. The optimized device with solution‐processed top TE achieves an AVT of 36% and a high CRI of 90. This work paves a simple and promising route towards low‐cost fabrication of power‐generating window.
Toward Ultra‐Efficient OLEDs: Approaches Based on Low Refractive Index Materials
Authors: Lee Jaeho , Song Jinouk , Park Jaehyeok , Yoo Seunghyup 
Published: February 2021

AbstractOrganic light‐emitting diodes (OLEDs) have successfully established themselves as light sources vital in high‐end mobile displays and television due to various advances made for a wide range of technical aspects from materials, devices, and processes to air‐tight packaging and systems. However, a significant portion of the generated excitons in OLEDs are still lost to various channels. Among them, excitation of surface plasmon polaritons (SPPs) is a critical source of exciton loss, the recovery of which often involves structuring in nanoscale. Herein, a nano‐pattern‐free approach is reviewed to reducing SPP loss that makes use of materials with low refractive index. Because of the limited availability of such low refractive index materials, a method to use a low extraordinary refractive index of birefringent organic semiconductors is explored. With the proposed method combined with common lens‐based outcoupling schemes and high refractive index substrates, it is shown that an ultrahigh external quantum efficiency of ≈72% in a green, single‐junction phosphorescent OLED is within the reach. Transient photoluminescence measurement is used to monitor the change in Purcell factor incurred by the use of the birefringent low refractive index layer and to further verify the validity of the proposed concept.
Eu2+Stabilized at Octahedrally Coordinated Ln3+Site Enabling Red Emission in Sr3LnAl2O7.5(Ln = Y or Lu) Phosphors
Authors: Hu Tao , Gao Yan , Molokeev Maxim S. , Xia Zhiguo , Zhang Qinyuan 
Published: February 2021

AbstractRed spectrum loss in phosphor‐converted light‐emitting diodes (pc‐LEDs) restricts high‐quality warm‐white lighting. Herein, two blue‐light excitable red‐emitting Sr3LnAl2O7.5:Eu (Ln = Y or Lu) phosphors are reported, and red emission originating from an unprecedented substitution model, with Eu2+occupied sixfold octahedrally coordinated lanthanide (Ln3+) sites is demonstrated. Site occupancy identification reveals that three different sites are occupied by Eu2+and one distinct site is occupied by Eu3+, and the Eu2+stabilized at Ln3+site accompanied by Eu3+selectively occupies at Sr2+site as a charge compensator. An anomalous prolonged Eu2+‐photoluminescence decay emission with increasing temperature in the low‐temperature region is demonstrated. This accounts for the trapped electrons, which are thermally released from shallow traps and eventually populate the Eu2+5d level to form an excited‐state Eu2+. The findings help better understand Eu2+occupancy and luminescence. These also provide a new perspective for the exploration of novel Eu2+activated oxide‐based red phosphor for pc‐LEDs.
Glycosyltransferase Co‐Immobilization for Natural Product Glycosylation: Cascade Biosynthesis of the C‐Glucoside Nothofagin with Efficient Reuse of Enzymes
Authors: Liu Hui , Tegl Gregor , Nidetzky Bernd 
Published: February 2021

AbstractSugar nucleotide‐dependent (Leloir) glycosyltransferases are synthetically important for oligosaccharides and small molecule glycosides. Their practical use involves one‐pot cascade reactions to regenerate the sugar nucleotide substrate. Glycosyltransferase co‐immobilization is vital to advance multi‐enzyme glycosylation systems on solid support. Here, we show glycosyltransferase chimeras with the cationic binding module Zbasic2 for efficient and well‐controllable two‐enzyme co‐immobilization on anionic (ReliSorb SP400) carrier material. We use the C‐glycosyltransferase from rice (Oryza sativa; OsCGT) and the sucrose synthase from soybean (Glycine max; GmSuSy) to synthesize nothofagin, the natural 3’‐C‐β‐d‐glucoside of the dihydrochalcone phloretin, with regeneration of uridine 5’‐diphosphate (UDP) glucose from sucrose and UDP. Exploiting enzyme surface tethering via Zbasic2, we achieve programmable loading of the glycosyltransferases (∼18 mg/g carrier; 60%–70% yield; ∼80% effectiveness) in an activity ratio (OsCGT:GmSuSy=∼1.2) optimal for the overall reaction rate (∼0.2 mmol h−1 g−1 catalyst; 30 °C, pH 7.5). Using phloretin solubilized at 120 mM as inclusion complex with 2‐hydroxypropyl‐β‐cyclodextrin, we demonstrate complete substrate conversion into nothofagin (∼52 g/L; 21.8 mg product h−1 g−1 catalyst) at 4% mass loading of the catalyst. The UDP‐glucose was recycled 240 times. The solid catalyst showed excellent reusability, retaining ∼40% of initial activity after 15 cycles of phloretin conversion (60 mM) with a catalyst turnover number of ∼273 g nothofagin/g protein used. Our study presents important progress towards applied bio‐catalysis with immobilized glycosyltransferase cascades.magnified image
Organocatalytic Enantioselective Synthesis of Tetrahydro‐Furanyl Spirooxindoles via [3+2] Annulations of 3‐Hydroxyoxindoles and Cyclic Ketolactams
Authors: Liu Yue , Zhang Ying , Huang Qian‐Wei , Gou Chuan , Li Qing‐Zhu , Dai Qing‐Song , Leng Hai‐Jun , Li Jun‐Long 
Published: February 2021

AbstractAsymmetric construction of pharmacologically interesting tetrahydrofuranyl spirooxindole frameworks has been achieved through organocatalytic [3+2] annulations of the readily available 3‐hydroxyoxindoles and pyrrolidone‐derived cyclic ketolactams. A variety of chiral spiro tetrahydrofuranyl products, which contain four contiguous stereocenters including two tetrasubstituted carbon centers, have been rapidly synthesized with remarkable results (up to 99% yield, >95:5 dr, and 99:1 er). Synthetic derivatization of the hemiketal moiety enables the installation of various halogen atoms into the structurally complex molecules in a stereospecific manner. Preliminary screening of anticancer bioactivity was performed, and 4 w showed obvious inhibitory capacity to the proliferation on a panel of cancer cell lines.magnified image
CNT Microtubes with Entrapped Fe3O4 Nanoparticles Remove Micropollutants through a Heterogeneous Electro‐Fenton Process at Neutral pH
Authors: Mohseni Mojtaba , Demeestere Kristof , Du Laing Gijs , Yüce Süleyman , Keller Robert G. , Wessling Matthias 
Published: February 2021

AbstractCatalyst‐coated carbon electrodes require two preparation stages: electrode assembly using carbon and polymeric binders and subsequent catalyst immobilization on the porous carbons electrode. Such conventional coating methods require several steps, which is time‐, chemical‐, and energy‐consuming. Also, polymeric binders can impair the porosity and block catalytic sites of final electrodes. This study introduces a novel one‐pot synthesis method in which Fe3O4 nanoparticles are entrapped within a multi‐walled carbon nanotube network, the latter being templated with microtubular geometry. Such carbon microtubes (CMT) represent a standalone geometry, serving as a binder‐free electrode for an energy‐efficient heterogeneous electro‐Fenton (HEF) process. Fe3O4‐containing CMTs remove carbamazepine (CBZ), a frequently detected pharmaceutical micropollutant in water bodies. While almost all literature reports degradation at acidic conditions requiring the use of acid, this material system functions at pH 7 ± 0.3 with lengthy reusability. The remarkable mineralization of the total oxidized CBZ emerges from the confinement of oxidation by‐products in CMTs’ 3D framework, where unselective radicals are formed once the electro‐generated H2O2 reacts with embedded Fe3O4. Additionally, the 3D network prevents the entrapped catalysts from leaching in acidic environments because of the increased local pH during electrolysis.
Bandgap‐Coupled Template Autocatalysis toward the Growth of High‐Purity sp2Nanocarbons
Authors: Gao Jun , Zhu Zhenxing , Shen Boyuan , Bai Yunxiang , Sun Silei , Wei Fei 
Published: February 2021

AbstractExtraordinary properties and great application potentials of carbon nanotubes (CNT) and graphene fundamentally rely on their large‐scale perfect sp2structure. Particularly for high‐end applications, ultralow defect density and ultrahigh selectivity are prerequisites, for which metal‐catalyzed chemical vapor deposition (CVD) is the most promising approach. Due to their structure and peculiarity, CNTs and graphene can themselves provide growth templates and nonlocal dual conductance, serving as template autocatalysts with tunable bandgap during the CVD. However, current growth kinetics models all focus on the external factors and edges. Here, the growth kinetics of sp2nanocarbons is elaborated from the perspective of template autocatalysis and holistic electronic structure. After reviewing current growth kinetics, various representative works involving CVD growth of different sp2nanocarbons are analyzed, to reveal their bandgap‐coupled kinetics and resulting selective synthesis. Recent progress is then reviewed, which has demonstrated the interlocking between the atomic assembly rate and bandgap of CNTs, with an explicit volcano dependence whose peak would be determined by the environment. In addition, the topological protection for perfect sp2structure and the defect‐induced perturbation for the interlocking are discussed. Finally, the prospects for the kinetic selective growth of perfect nanocarbons are proposed.
Platelet‐Mimicking Therapeutic System for Noninvasive Mitigation of the Progression of Atherosclerotic Plaques
Authors: Ma Yi , Ma Yuxuan , Gao Mengqiu , Han Zhihao , Jiang Wen , Gu Yueqing , Liu Yi 
Published: February 2021

AbstractAtherosclerotic plaque is the primary cause of cardiovascular disorders and remains a therapeutic hurdle for the early intervention of atherosclerosis. Traditional clinical strategies are often limited by surgery‐related complications or unsatisfactory effects of long‐term drug administration. Inspired by the plaque‐binding ability of platelets, a biomimic photodynamic therapeutic system is designed to mitigate the progression of atherosclerotic plaques. This system is composed of photosensitizer‐loaded upconversion nanoparticle cores entrapped in the platelet membrane. The platelet membrane coating facilitates specific targeting of the therapeutic system to macrophage‐derived foam cells, the hallmark, and main component of early stage atherosclerotic plaques, which is firmly confirmed by in vivo fluorescent and single‐photon emission computed tomography/computed tomography (SPECT/CT) radionuclide imaging. Importantly, in vivo phototherapy guided by SPECT/CT imaging alleviates plaque progression. Further immunofluorescence analysis reveals foam cell apoptosis and ameliorated inflammation. This biomimic system, which combines plaque‐binding with radionuclide imaging guidance, is a novel, noninvasive, and potent strategy to mitigate the progression of atherosclerotic plaque.
Nanostructured Dense Collagen‐Polyester Composite Hydrogels as Amphiphilic Platforms for Drug Delivery
Authors: Wang Xiaolin , Ronsin Olivier , Gravez Basile , Farman Nicolette , Baumberger Tristan , Jaisser Frédéric , Coradin Thibaud , Hélary Christophe 
Published: February 2021

AbstractAssociating collagen with biodegradable hydrophobic polyesters constitutes a promising method for the design of medicated biomaterials. Current collagen‐polyester composite hydrogels consisting of pre‐formed polymeric particles encapsulated within a low concentrated collagen hydrogel suffer from poor physical properties and low drug loading. Herein, an amphiphilic composite platform associating dense collagen hydrogels and up to 50 wt% polyesters with different hydrophobicity and chain length is developed. An original method of fabrication is disclosed based on in situ nanoprecipitation of polyesters impregnated in a pre‐formed 3D dense collagen network. Composites made of poly(lactic‐co‐glycolic acid) (PLGA) and poly(lactic acid) (PLA) but not polycaprolactone (PCL) exhibit improved mechanical properties compared to those of pure collagen dense hydrogels while keeping a high degree of hydration. Release kinetics of spironolactone, a lipophilic steroid used as a drug model, can be tuned over one month. No cytotoxicity of the composites is observed on fibroblasts and keratinocytes. Unlike the incorporation of pre‐formed particles, the new process allows for both improved physical properties of collagen hydrogels and controlled drug delivery. The ease of fabrication, wide range of accessible compositions, and positive preliminary safety evaluations of these collagen‐polyesters will favor their translation into clinics in wide areas such as drug delivery and tissue engineering.
The Dual Function of KDM5C in Both Gene Transcriptional Activation and Repression Promotes Breast Cancer Cell Growth and Tumorigenesis
Authors: Shen Hai‐feng , Zhang Wen‐juan , Huang Ying , He Yao‐hui , Hu Guo‐sheng , Wang Lei , Peng Bing‐ling , Yi Jia , Li Ting‐ting , Rong Rui , Chen Xiao‐yan , Liu Jun‐yi , Li Wen‐juan , Ohgi Kenny , Li Shao‐Wei , Rosenfeld Michael G. , Liu Wen 
Published: February 2021

AbstractEmerging evidence suggested that epigenetic regulators can exhibit both activator and repressor activities in gene transcriptional regulation and disease development, such as cancer. However, how these dual activities are regulated and coordinated in specific cellular contexts remains elusive. Here, it is reported that KDM5C, a repressive histone demethylase, unexpectedly activates estrogen receptor alpha (ERα)‐target genes, and meanwhile suppresses type I interferons (IFNs) and IFN‐stimulated genes (ISGs) to promote ERα‐positive breast cancer cell growth and tumorigenesis. KDM5C‐interacting protein, ZMYND8, is found to be involved in both processes. Mechanistically, KDM5C binds to active enhancers and recruits the P‐TEFb complex to activate ERα‐target genes, while inhibits TBK1 phosphorylation in the cytosol to repress type I IFNs and ISGs. Pharmacological inhibition of both ERα and KDM5C is effective in inhibiting cell growth and tumorigenesis. Taken together, it is revealed that the dual activator and repressor nature of an epigenetic regulator together contributes to cancer development.
Unraveling the Li Penetration Mechanism in Polycrystalline Solid Electrolytes
Authors: Tantratian Karnpiwat , Yan Hanghang , Ellwood Kevin , Harrison Elisa T. , Chen Lei 
Published: February 2021

AbstractLithium dendrite penetration has been widely evidenced in ceramic solid electrolytes (SEs), which are expected to suppress Li dendrite formation due to their ultrahigh elastic modulus. This work aims to reveal the mechanism of Li penetration in polycrystalline SEs through electro‐chemo‐mechanical phase‐field model, using Li7La3Zr2O12 (LLZO) as the model material. The results show the Li penetration patterns are influenced by both mechanical and electronic properties of the microstructures, i.e., grain boundaries (GBs). Li nucleates at the GB junctions on the Li/SE interface and propagates along the GB, at which the interfacial compressive stress is small due to the GB softening. Moreover, the excess trapped electrons at the GB may trigger isolated Li nucleation sites, abruptly increasing the Li penetration depth. High‐throughput simulations yield a phase map of Li penetration patterns under different trapped electrons concentrations and GB/grain elastic modulus mismatch. The map can quantitatively inform whether the mechanical or electronic properties dominate Li penetration morphologies, providing a strategy for the design of improved SE materials.
Atomic Gradient Structure Alters Electronic Structure in 3D across the Bulk and Enhances Photoactivity
Authors: Ren Peng , Lu Zexi , Song Miao , Lee Jaewon , Zheng Jian , Sushko Peter V. , Li Dongsheng 
Published: February 2021

AbstractUnderstanding structure–function relationships enables the design of materials with tailored functionalities. The long‐standing challenge is to design materials with high active volume to improve efficiency. Tailored grain boundaries and lattice defects are traditionally used to tune the electronic structure near interfaces or defects to promote electron and hole separation. However, the active volume of point defect sites or interfaces in these traditional photocatalysts is extremely low. This study reports a structure with continuous atomic positional deformation across the bulk, altering the electronic structure in 3D and creating a significantly higher active volume. Such a structure in anatase is obtained and tuned by phase transformation during the heating process. Transmission electron microscopy and density functional theory results reveal that atomic deformations result in continuous band bending across the particles, facilitating electron–hole separation, inhibiting their recombination, and inducing dramatically enhanced photoactivity. These findings enable a different materials design paradigm that can potentially be harnessed for a broad range of applications.
Exceptional Capacitance Enhancement of a Non‐Conducting COF through Potential‐Driven Chemical Modulation by Redox Electrolyte
Authors: Kushwaha Rinku , Haldar Sattwick , Shekhar Pragalbh , Krishnan Akshara , Saha Jayeeta , Hui Pramiti , Vinod Chathakudath Prabhakaran , Subramaniam Chandramouli , Vaidhyanathan Ramanathan 
Published: February 2021

AbstractCapacitors are the most practical high‐storage and rapid charge‐release devices. The number of ions stored per unit area and their interaction strength with the electrode dictates capacitor‐performance. Microporous materials provide a high storage surface and optimal interactions. Adsorbing electron‐rich and easily polarizable molecules into microporous electrodes is expected to boost Faradaic pseudo‐activity. If such electrode–electrolyte interactions can be made as a potential‐driven reversible process, the resulting capacitors would be adaptable and device‐friendly. A composite covalent organic framework (COF)‐carbon electrode with redox‐active KI is combined in an H2SO4 electrolyte for the first time. This composite electrode benefits from the redox‐functionality of COF and electronic conductivity of carbon, leading to superior capacitative activity. Operando spectro‐electrochemical measurements reveal the existence of multiple polyiodide species, although the I3− is the predominantly electroactive species adsorbing on the microporous triazine‐phenol COF electrode. A systematic fabrication of the flexible solid‐state devices using the COF‐redox‐electrolyte reveals a high areal capacitance of 270 ± 11 mF cm−2 and gravimetric capacitance of 57 ± 8 F g−1. The inclusion of KI in H2SO4 (electrolyte) yields an approximately eight‐fold enhancement in solid‐state gravimetric specific capacitance. The imine‐COF retains 89% of its capacity even after 10 000 cycles.