bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel 2D Transition‐Metal Carbides: Ultrahigh Performance Electrocatalysts for Overall Water Splitting and Oxygen Reduction
Authors: Yu Yadong , Zhou Jian , Sun Zhimei 
Published: April 2020

AbstractSearching for highly efficient, stable, and cost‐effective electrocatalysts for water splitting and oxygen reduction reaction (ORR) is critical for renewable energies, yet it remains a great challenge. Here, by performing an unbiased structural search and first‐principles calculations, the electrocatalytic performance of the emerging 2D transitional‐metal carbides, MC2 (M represents the transition metal of Ti, V, Nb, Ta, and Mo, C is carbon), is systematically investigated. Owing to their super stability and outstanding electronic conductivity, fast charge transfer kinetics is allowed during catalysis. Specifically, NbC2, TaC2, and MoC2 possess excellent hydrogen evolution reaction (HER) performance under the reaction by the Volmer‐Heyrovsky mechanism. Moreover, taking advantage of the dual‐active‐site catalytic mechanism for oxygen evolution reaction (OER) and ORR over traditional single‐active‐site mechanism, TaC2 presents promising bifunctional electrocatalytic activity with a low overpotential of 0.06 and 0.37 V for HER and ORR, respectively. Meanwhile, the low overpotential endows MoC2 remarkable multifunctional electrocatalytic performance in overall water splitting (0.001 V for HER, 0.45 V for OER) and ORR (0.47 V). These intriguing results demonstrate the robust applicability of MC2 monolayers as effective electrocatalysts.
Insights into the Photothermal Conversion of 2D MXene Nanomaterials: Synthesis, Mechanism, and Applications
Authors: Xu Dingxin , Li Zhidong , Li Laisheng , Wang Jing 
Published: April 2020

AbstractSince their discovery in 2011, 2D transition metal carbide/nitride (MXene) materials have received extensive interest due to their unique planar structure, chemical diversity, and superior physiochemical features. Very recently, MXenes have demonstrated outstanding photothermal conversion by virtue of excellent electromagnetic wave absorption capacity and a localized surface plasmon resonance effect. Photothermal conversion is an efficient way to utilize solar energy that allows the transformation of solar illumination into thermal energy, thus enabling MXenes to be applied in various fields, such as solar steam generation and biomedicals. However, the light‐to‐heat capability of MXenes has been paid much less attention until now. Recent progress in photothermal MXenes is reviewed to provide a comprehensive understanding of their photothermal conversion mechanism and applications. First, synthetic strategies of MXenes and their nanocomposites will be briefly summarized, and the discussion of the photothermal conversion mechanism and, most importantly, current advances in their photothermal applications will follow. It is highly anticipated that 2D MXenes, through elaborate material design and interdisciplinary approach, will become one of the mainstream photothermal materials and their application fields will also be expanded in the near future.
Extreme Elasticity Anisotropy in Molecular Glasses
Authors: Cang Yu , Wang Zuyuan , Bishop Camille , Yu Lian , Ediger M. D. , Fytas George 
Published: April 2020

AbstractGlasses are generally assumed to be isotropic and there are no literature reports of elastic anisotropy for molecular glasses. However, as glasses formed by physical vapor deposition can be structurally anisotropic, it is of interest to investigate the elastic anisotropy in these materials. Micro‐Brillouin light spectroscopy is used in several experimental geometries to determine the elastic stiffness tensors of three glass films of itraconazole vapor‐deposited at substrate temperatures (Tsub) of 330, 315, and 290 K, respectively. Significant elastic anisotropy is observed and, in these glasses, the elastic anisotropy shows a strong correlation with the molecular orientation. The out‐of‐plane and in‐plane Young's moduli of the high Tsub (330 K) sample, which features a predominantly vertical molecular orientation, exhibit a high anisotropy ratio of 2.2. The observed elastic anisotropy is much larger than those previously observed in liquid crystals and even many crystalline solids.
A Double‐Layered Microneedle Platform Fabricated through Frozen Spray‐Coating
Authors: Ning Xiaoyu , Wiraja Christian , Lio Daniel Chin Shiuan , Xu Chenjie 
Published: April 2020

AbstractThis work reports a frozen spray‐coating method for the fabrication of double‐layered microneedles (MNs). Taking swellable methacrylated hyaluronic acid (MeHA)‐derived MNs as the model, both hydrophobic molecules (Nile red, Cy5) and hydrophilic ones (FITC, FITC‐Dextran, Insulin) can be homogeneously coated without impacting the mechanical properties of the original MeHA MNs. The prepared double‐layered MNs can execute multiple roles. It is demonstrated that insulin‐coated MeHA double‐layered MNs allow the effective delivery of the insulin into circulation of mice for controlling the blood glucose level while they also permit the extraction of skin interstitial fluid for the timely analysis of the biomarker (glucose).
Nanoscaled Fractal Superstructures via Laser Patterning—A Versatile Route to Metallic Hierarchical Porous Materials
Authors: Reinhardt Hendrik , Kroll Moritz , Karstens Sarah L. , Schlabach Sabine , Hampp Norbert A. , Tallarek Ulrich 
Published: April 2020

AbstractA laser‐based procedure for the preparation of metallic hierarchical porous materials is introduced and exemplified on tin, copper, silicon, titanium, and tungsten surfaces to demonstrate its general applicability. The impact of suitably tuned nanosecond laser pulses triggers a process in which laser‐induced metal ablation and instantaneous recondensation of partially oxidized metals lead to cauliflower‐like superstructures comprising a hybrid micro‐/nanopatterning. Repeated scanning with the intense focused beam over the surface creates microstructures of hierarchically tunable porosity in a layer‐by‐layer design. The 3D morphology of these superstructures is analyzed using tomographic data based on focused ion‐beam scanning electron microscopy to return a fractal dimension of Df = 2.79—practically identical to a natural cauliflower (Df ≈ 2.8), even though the plant is four orders of magnitude larger than the superstructures generated through the laser process. The high Df value signifies a complex morphology that boasts a huge external surface. The introduced concept enables convenient access to a variety of metallic hierarchical porous materials, which are key to performance in environmentally and technologically relevant areas like energy generation, storage, and conversion, as well as sensing and catalysis.
Iodine/Manganese Catalyzed Sulfenylation of Indole via Dehydrogenative Oxidative Coupling in Anisole
Authors: Li Weihe , Wang Hao , Liu Shengping , Feng Hua , Benassi Enrico , Qian Bo 
Published: April 2020

AbstractThis protocol describes an iodine/manganese catalytic system for dehydrogenative oxidative coupling reaction of indoles with thiols in anisole. Particularly, the dual roles of anisole have been first demonstrated as a solvent and as a promoter via the formation of an oxonium ion intermediate to accelerate the generation of products. A series of sulfenylindoles are readily constructed under aerobic mild reaction conditions. In addition, the achievement for preparing anticancer and anti‐AIDS drugs testifies the practicability of this approach. The mechanism studies disclose probable alternative pathways and a single‐electron transfer process are involved in this transformation.magnified image
Synthesis of 2‐(Arylthio)indolenines via Chemoselective Arylation of Thio‐Oxindoles with Arynes
Authors: Saputra Adi , Fan Rong , Yao Tuanli , Chen Jian , Tan Jiajing 
Published: April 2020

AbstractA chemoselective S‐arylation reaction of thio‐oxindoles with arynes is presented. The reaction was performed under mild conditions and provided a straightforward synthesis of 2‐(arylthio)indolenines in good to excellent yields. Besides, this simple operational protocol is not only scalable but also has good functional group compatibilities and substrate scope. Thus, our protocol should allow for the expansion of chemical space via developing new scaffolds of thioimidates that are difficult to synthesize otherwise.magnified image
Innovative Precision Gene‐Editing Tools in Personalized Cancer Medicine
Authors: Dai Xiaofeng , Blancafort Pilar , Wang Peiyu , Sgro Agustin , Thompson Erik W. , Ostrikov Kostya (Ken) 
Published: April 2020

AbstractThe development of clustered regularly interspaced short palindromic repeats (CRISPR) has spurred a successive wave of genome‐engineering following zinc finger nucleases and transcription activator‐like effector nucleases, and made gene‐editing a promising strategy in the prevention and treatment of genetic diseases. However, gene‐editing is not widely adopted in clinics due to some technical issues that challenge its safety and efficacy, and the lack of appropriate clinical regulations allowing them to advance toward improved human health without impinging on human ethics. By systematically examining the oncological applications of gene‐editing tools and critical factors challenging their medical translation, genome‐editing has substantial contributions to cancer driver gene discovery, tumor cell epigenome normalization, targeted delivery, cancer animal model establishment, and cancer immunotherapy and prevention in clinics. Gene‐editing tools, epitomized by CRISPR, are predicted to represent a promising strategy toward the precise control of cancer initiation and development. However, some technical problems and ethical concerns are serious issues that need to be appropriately addressed before CRISPR can be incorporated into the next generation of molecular precision medicine. In this light, new technical developments to limit off‐target effects are discussed herein, and the use of gene‐editing approaches for treating otherwise incurable cancers is brought into focus.
Quantitative Mapping of Liver Hypoxia in Living Mice Using Time‐Resolved Wide‐Field Phosphorescence Lifetime Imaging
Authors: Liu Yawei , Gu Yuyang , Yuan Wei , Zhou Xiaobo , Qiu Xiaochen , Kong Mengya , Wang Qingbing , Feng Wei , Li Fuyou 
Published: April 2020

AbstractHypoxia has been identified to contribute the pathogenesis of a wide range of liver diseases, and therefore, quantitative mapping of liver hypoxia is important for providing critical information in the diagnosis and treatment of hepatic diseases. However, the existing imaging methods are unsuitable to quantitatively assess liver hypoxia due to the need of liver‐specific contrast agents and be easily affected by other imaging factors. Here, a time‐resolved lifetime‐based imaging method is established for quantitative mapping of the distribution of hypoxia in the livers of mice by combining a wide‐field luminescence lifetime imaging system with an oxygen‐sensitive nanoprobe. It is shown that the method is suitable for real‐time quantification of the change of oxygen pressure in the process of hepatic ischemia‐reperfusion of the mouse. Moreover, the developed lifetime imaging methodology is used to quantitatively map liver hypoxia regions in the mouse model of orthotopic liver tumor, where the average oxygen pressure in tumorous liver is far below the normal liver.
Progress in Stability of Organic Solar Cells
Authors: Duan Leiping , Uddin Ashraf 
Published: April 2020

AbstractThe organic solar cell (OSC) is a promising emerging low‐cost thin film photovoltaics technology. The power conversion efficiency (PCE) of OSCs has overpassed 16% for single junction and 17% for organic–organic tandem solar cells with the development of low bandgap organic materials synthesis and device processing technology. The main barrier of commercial use of OSCs is the poor stability of devices. Herein, the factors limiting the stability of OSCs are summarized. The limiting stability factors are oxygen, water, irradiation, heating, metastable morphology, diffusion of electrodes and buffer layers materials, and mechanical stress. The recent progress in strategies to increase the stability of OSCs is surveyed, such as material design, device engineering of active layers, employing inverted geometry, optimizing buffer layers, using stable electrodes and encapsulation materials. The International Summit on Organic Photovoltaic Stability guidelines are also discussed. The potential research strategies to achieve the required device stability and efficiency are highlighted, rendering possible pathways to facilitate the viable commercialization of OSCs.
Vapor‐Deposited Cs2AgBiCl6 Double Perovskite Films toward Highly Selective and Stable Ultraviolet Photodetector
Authors: Wang Ming , Zeng Peng , Wang Zenghui , Liu Mingzhen 
Published: April 2020

AbstractDouble perovskites have shown great potentials in addressing the toxicity and instability issues of lead halide perovskites toward practical applications. However, fabrication of high‐quality double perovskite thin films has remained challenging. Here, sequential vapor deposition is used to fabricate high‐quality Cs2AgBiCl6 perovskite films with balanced stoichiometry, superior morphology, and highly oriented crystallinity, with an indirect bandgap of 2.41 eV. Using a diode structure, self‐powered Cs2AgBiCl6 ultraviolet (UV) photodetectors are demonstrated with high selectivity centered at 370 nm, with low dark current density (≈10−7 mA cm−2), high photoresponsivity (≈10 mA W−1), and detectivity (≈1012 Jones). Its detectivity is among the highest in all double‐perovskite‐based photodetectors reported to date and surpassing the performance of other perovskite photodetectors as well as metal oxide in the UV range. The devices also show excellent environmental and irradiation stability comparable to state‐of‐the‐art UV detectors. The findings help pave the way toward application of double perovskites in optoelectronic devices.
Recent Advances in Alkyne Hydroamination as a Powerful Tool for the Construction of C−N Bonds
Authors: Tashrifi Zahra , Mohammadi Khanaposhtani Mohammad , Biglar Mahmood , Larijani Bagher , Mahdavi Mohammad 
Published: April 2020

AbstractAlkyne hydroamination reaction has attracted many researchers due to its capability to form the required C−N bonds in the synthesis of the biologically and pharmacologically active N‐heterocycles. Hence, in this review, a comprehensive and updated summary of the research progress in this area (from 2014 on) is presented. In order to provide an easier access to the required information, a brief and concise description of the reaction mechanisms and preparation of precursors is also included, where possible. Accordingly, the alkyne hydroamination reactions are classified and summarized based on the type of hydroamination (inter‐ or intramolecular) and each class is further subdivided according to the number of members in the rings, so as to help the researchers in designing new N‐hetrocycles.
Controlled Generation of 9‐Boratriptycene by Lewis Adduct Dissociation: Accessing a Non‐Planar Triarylborane
Authors: Chardon Aurélien , Osi Arnaud , Mahaut Damien , Doan Thu‐Hong , Tumanov Nikolay , Wouters Johan , Fusaro Luca , Champagne Benoît , Berionni Guillaume 
Published: April 2020

AbstractA highly bent triarylborane, 9‐boratriptycene, was generated in solution by selective protodeboronation of the corresponding tetra‐aryl boron ate complex with the strong Brønsted acid HNTf2. The iptycene core confers enhanced Lewis acidity to 9‐boratriptycene, making it unique in terms of structure and reactivity. We studied the stereoelectronic properties of 9‐boratriptycene by quantifying its association with small N‐ and O‐centered Lewis bases, as well as with sterically hindered phosphines. The resultant Lewis adducts exhibited unique structural, spectroscopic, and photophysical properties. Beyond the high pyramidalization of the 9‐boratriptycene scaffold and its low reorganization energy upon Lewis base coordination, quantum chemical calculations revealed that the absence of π donation from the triptycene aryl rings to the boron vacant pz orbital is one of the main reasons for its high Lewis acidity.
Sterically Shielded Heptamethine Cyanine Dyes for Bioconjugation and High Performance Near‐Infrared Fluorescence Imaging
Authors: Li Dong‐Hao , Schreiber Cynthia L. , Smith Bradley D. 
Published: April 2020

AbstractThe near‐infrared window of fluorescent heptamethine cyanine dyes greatly facilitates biological imaging because there is deep penetration of the light and negligible background fluorescence. However, dye instability, aggregation, and poor pharmacokinetics are current drawbacks that limit performance and the scope of possible applications. All these limitations are simultaneously overcome with a new molecular design strategy that produces a charge balanced and sterically shielded fluorochrome. The key design feature is a meso‐aryl group that simultaneously projects two shielding arms directly over each face of a linear heptamethine polyene. Cell and mouse imaging experiments compared a shielded heptamethine cyanine dye (and several peptide and antibody bioconjugates) to benchmark heptamethine dyes and found that the shielded systems possess an unsurpassed combination of photophysical, physiochemical, and biodistribution properties that greatly enhance bioimaging performance.
Synthesis of a pyrene‐functionalized hyperbranched polyethylene ternary copolymer for efficient graphite exfoliation in chloroform and formation of ethylene‐vinyl acetate/graphene nanocomposites
Authors: Luo Zhenggang , Ye Huijian , Hu Jiawei , Hu Te , Zhang Boyuan , Zhang Xuanhe , Xu Lixin 
Published: April 2020

AbstractA strategy for preparing ethylene‐vinyl acetate (EVA)/graphene nanocomposites from liquid‐phase exfoliated graphene has been explored with the use of a pyrene‐functionalized hyperbranched polyethylene (HBPE) ternary copolymer, HBPE@Py@PMA, as stabilizer for graphite exfoliation. The HBPE@Py@PMA was synthesized by combining the Pd‐diimine‐catalyzed chain walking ternary ethylene copolymerization and atomic transfer radical polymerization techniques and has been confirmed to possess a HBPE core simultaneously bearing pyrene terminal groups and polymethacrylate side chains. As stabilizer, it is found to effectively promote graphite exfoliation in CHCl3 to render high‐quality few‐layer graphene with an efficiency as high as 43%. Meanwhile, it can be steadily adsorbed on the exfoliated graphene surface to concurrently render functionalized graphene well dispersible in EVA matrix with strong interfacial interactions. This allows us to obtain EVA/graphene nanocomposites from resulting graphene dispersion through simple solution mixing process. By adding only 0.5 wt% of graphene, the dielectric constant of resulting composite increases by 55% compared to pure EVA, with a dielectric loss only 0.012. The role mechanism of the HBPE@Py@PMA for promoting graphite exfoliation in CHCl3 and the formation of EVA/graphene nanocomposites from the resulting graphene has been proposed.
Phase behavior, in vitro drug release, and antibacterial activity of thermoresponsive poloxamer–polyvinyl alcohol hydrogel‐loaded mupirocin nanoparticles
Authors: Kamlungmak Sukanjana , Rugmai Supagorn , Tinpun Kittiya , Nakpheng Titpawan , Srichana Teerapol 
Published: April 2020

AbstractThis research was designed to develop thermoresponsive poloxamer (P407)–polyvinyl alcohol (PVA) hydrogels to deliver mupirocin nanoparticles for wound healing. The mupirocin nanoparticles containing drug and gelatin or poly (acrylic acid) were prepared by spray drying. The hydrogel phases were evaluated by small‐angle X‐ray scattering. An in vitro drug release study was performed and the antibacterial activity of mupirocin nanoparticles‐loaded hydrogel (MLH) was evaluated. Fourier transform infrared and proton nuclear magnetic resonance spectrum spectra of the mupirocin nanoparticles indicated a weak interaction between mupirocin and the carriers of carbopol and gelatin. The mupirocin molecules were surrounded by the carrier molecules. The MLH appeared to exhibit single diamond (Fd3m) phase behavior similar to P407 and the hydrogel base. The release of MLH in vitro indicated first‐order kinetics (R2 = .9839–.8868). The MLH showed lower minimum inhibitory concentrations and minimum bactericidal concentrations against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli than mupirocin ointment.
Improving the hydrophilicity of polyethersulfone membrane by the combination of grafting technology and reverse thermally induced phase separation method
Authors: Yang Hang , Gao Chun‐Mei , Liu Sheng‐Hui , Ji Shi‐Feng , Chen Hong‐Yu , Chen Jin‐Chao 
Published: April 2020

AbstractIn this work, surface grafting modification technology was combined with reverse thermally induced phase separation (RTIPS) method in order to improve the structure and permanent hydrophilicity of polyethersulfone (PES) membranes. Acrylic solution with different concentrations was grafted on the surface of PES membranes while grafting temperature and grafting time were also varied. The modified PES membranes were characterized in all aspects. Attenuated total reflectance Fourier transform‐infrared confirmed successful modification of the PES membrane by grafting acrylic acid. Scanning electron microscopy revealed that homogeneous porous top surface as well as spongy‐like cross‐section structure appeared in the membrane by RTIPS procedure. Moreover, porosity was affected by changes of acrylic acid concentration, grafting temperature, and grafting time. Atomic force microscopy showed that grafting acrylic acid gave a reduction in roughness of PES membrane. Combined with the decreased values of contact angle, the hydrophilicity and antifouling performance of the PES membrane were improved. The pure water flux and BSA rejection rate of the grafted PES membranes were remarkably improved for pure PES membrane and attained a maximum, which was 1,646.24 L/(m2h) and 94.5%, respectively. The long‐term test demonstrated that grafting membranes exhibited outstanding elevated water flux recovery ratio (>85%).
A step‐by‐step protocol for meiotic chromosome counts in flowering plants: A powerful and economical technique revisited
Authors: Windham Michael D. , Pryer Kathleen M. , Poindexter Derick B. , Li Fay‐Wei , Rothfels Carl J. , Beck James B. 
Published: April 2020

PremiseCounting chromosomes is a fundamental botanical technique, yet it is often intimidating and increasingly sidestepped. Once mastered, the basic protocol can be applied to a broad range of taxa and research questions. It also reveals an aspect of the plant genome that is accessible with only the most basic of resources—access to a microscope with 1000× magnification is the most limiting factor.Methods and ResultsHere we provide a detailed protocol for choosing, staining, and squashing angiosperm pollen mother cells. The protocol is supplemented by figures and two demonstration videos.ConclusionsThe protocol we provide will hopefully demystify and reinvigorate a powerful and once commonplace botanical technique that is available to researchers regardless of their location and resources.