Highly efficient light‐harvesting systems were successfully fabricated in aqueous solution based on the supramolecular self‐assembly of a water‐soluble pillar6arene (WP6), a salicylaldehyde azine ...derivative (G), and two different fluorescence dyes, Nile Red (NiR) or Eosin Y (ESY). The WP6‐G supramolecular assembly exhibits remarkably improved aggregation‐induced emission enhancement and acts as a donor for the artificial light‐harvesting system, and NiR or ESY, which are loaded within the WP6‐G assembly, act as acceptors. An efficient energy‐transfer process takes place from the WP6‐G assembly not only to NiR but also to ESY for these two different systems. Furthermore, both of the WP6‐G‐NiR and WP6‐G‐ESY systems show an ultrahigh antenna effect at a high donor/acceptor ratio.
Light‐harvesting systems were fabricated in aqueous solution by supramolecular self‐assembly of a water‐soluble pillar6arene (WP6), a salicylaldehyde azine derivative (G, acting as donor), and two different fluorescence dyes, Nile Red or Eosin Y. The dye is loaded within the WP6‐G assembly and acts as an acceptor.
An artificial light‐harvesting system with sequential energy‐transfer process was fabricated based on a supramolecular strategy. Self‐assembled from the host–guest complex formed by water‐soluble ...pillar5arene (WP5), a bola‐type tetraphenylethylene‐functionalized dialkyl ammonium derivative (TPEDA), and two fluorescent dyes, Eosin Y (ESY) and Nile Red (NiR), the supramolecular vesicles achieve efficient energy transfer from the AIE guest TPEDA to ESY. ESY can function as a relay to further transfer the energy to the second acceptor NiR and realize a two‐step sequential energy‐transfer process with good efficiency. By tuning the donor/acceptor ratio, bright white light emission can be successfully achieved with a CIE coordinate of (0.33, 0.33). To better mimic natural photosynthesis and make full use of the harvested energy, the WP5⊃TPEDA‐ESY‐NiR system can be utilized as a nanoreactor: photocatalyzed dehalogenation of α‐bromoacetophenone was realized with 96 % yield in aqueous medium.
It takes two to FRET: An artificial light‐harvesting system with a two‐step sequential energy‐transfer process in a relay mode was fabricated using a supramolecular strategy. It can be used as a nanoreactor for efficient photochemical catalysis. Moreover, bright white light emission can be successfully achieved with a CIE coordinate of (0.33, 0.33).
Noncovalent macrocycle‐confined supramolecular purely organic room‐temperature phosphorescence (RTP) is a current research hotspot. Herein, a high‐efficiency noncovalent polymerization‐activated ...near‐infrared (NIR)‐emissive RTP‐harvesting system in aqueous solution based on the stepwise confinement of cucurbit7uril (CB7) and β‐cyclodextrin‐grafted hyaluronic acid (HACD), is reported. Compared with the dodecyl‐chain‐bridged 6‐bromoisoquinoline derivative (G), the dumbbell‐shaped assembly G⊂CB7 presents an appeared complexation‐induced RTP signal at 540 nm via the first confinement of CB7. Subsequently, benefitting from the stepwise confinement encapsulation of the β‐cyclodextrin cavity, the subsequent noncovalent polymerization of the binary G⊂CB7 assembly enabled by HACD can contribute to the further‐enhanced RTP emission intensity approximately eight times in addition to an increased lifetime from 59.0 µs to 0.581 ms. Moreover, upon doping a small amount of two types of organic dyes, Nile blue or tetrakis(4‐sulfophenyl)porphyrin as an acceptor into the supramolecular confinement assembly G⊂CB7 @ HACD, efficient RTP energy transfer occurs accompanied by a long‐lived NIR‐emitting performance (680 and 710 nm) with a high donor/acceptor ratio. Intriguingly, the prepared RTP‐harvesting system is successfully applied for targeted NIR imaging of living tumor cells by utilizing the targeting ability of hyaluronic acid, which provides a new strategy to create advanced water‐soluble NIR phosphorescent materials.
A highly efficient noncovalent polymerization‐activated phosphorescence‐harvesting system is successfully constructed in aqueous solution based on the stepwise confinement of cucurbit7uril and β‐cyclodextrin‐grafted hyaluronic acid, which shows high phosphorescence energy transfer efficiency accompanied by a long‐lived near‐infrared (NIR) emitting performance, and is ultimately applied for NIR targeted imaging of cancer cells.
Social media has become a popular venue for individuals to share the results of their own analysis on financial securities. This paper investigates the extent to which investor opinions transmitted ...through social media predict future stock returns and earnings surprises. We conduct textual analysis of articles published on one of the most popular social media platforms for investors in the United States. We also consider the readers' perspective as inferred via commentaries written in response to these articles. We find that the views expressed in both articles and commentaries predict future stock returns and earnings surprises.
Benzofuran compounds are a class of compounds that are ubiquitous in nature. Numerous studies have shown that most benzofuran compounds have strong biological activities such as anti-tumor, ...antibacterial, anti-oxidative, and anti-viral activities. Owing to these biological activities and potential applications in many aspects, benzofuran compounds have attracted more and more attention of chemical and pharmaceutical researchers worldwide, making these substances potential natural drug lead compounds. For example, the recently discovered novel macrocyclic benzofuran compound has anti-hepatitis C virus activity and is expected to be an effective therapeutic drug for hepatitis C disease; novel scaffold compounds of benzothiophene and benzofuran have been developed and utilized as anticancer agents. Novel methods for constructing benzofuran rings have been discovered in recent years. A complex benzofuran derivative is constructed by a unique free radical cyclization cascade, which is an excellent method for the synthesis of a series of difficult-to-prepare polycyclic benzofuran compounds. Another benzofuran ring constructed by proton quantum tunneling has not only fewer side reactions, but also high yield, which is conducive to the construction of complex benzofuran ring systems. This review summarizes the recent studies on the various aspects of benzofuran derivatives including their important natural product sources, biological activities and drug prospects, and chemical synthesis, as well as the relationship between the bioactivities and structures.
Benzofuran compounds are a class of compounds that are ubiquitous in nature.
Interfacial engineering and elemental doping are the two parameters to enhance the catalytic behavior of cobalt nitrides for the alkaline hydrogen evolution reaction (HER). However, simultaneously ...combining these two parameters to improve the HER catalytic properties of cobalt nitrides in alkaline media is rarely reported and also remains challenging in acidic media. Herein, it is demonstrated that high‐valence non‐3d metal and non‐metal integration can simultaneously achieve Co‐based nitride/oxide interstitial compound phase boundaries on stainless steel mesh (denoted Mo‐Co5.47N/N‐CoO) for efficient HER in alkaline and acidic media. Density functional theory (DFT) calculations show that the unique structure does not only realize multi‐active sites, enhanced water dissociation kinetics, and low hydrogen adsorption free energy in alkaline media, but also enhances the positive charge density of hydrogen ions (H+) to effectively allow H+ to receive electrons from the catalysts surface toward promoting the HER in acidic media. As a result, the as‐prepared Mo‐Co5.47N/N‐CoO demands HER overpotential of −28 mV@10 mA cm−2 in an alkaline medium, and superior to the commercial Pt/C at a current density > 44 mA cm−2 in acidic medium. This work paves a useful strategy to design efficient cobalt‐based electrocatalysts for HER and beyond.
Herein, a non‐3d metal (Mo) and non‐metal nitrogen (N) doping strategy could facilitate the formation of 3D porous terrace‐like in situ Mo‐Co5.47N/N‐CoO heterojunctions on stainless steel mesh. The optimized catalyst achieves simultaneous modulation of active site number, water dissociation, and hydrogen adsorption free energy in both alkaline and acidic electrolytes.
The many useful features possessed by pillararenes (PAs; e.g. rigid, capacious, and hydrophobic cavities, as well as exposed functional groups) have led to a tremendous increase in their popularity ...since their first discovery in 2008. In this Minireview, we emphasize the use of functionalized PAs and their assembled supramolecular materials in the field of catalysis. We aim to provide a fundamental understanding and mechanism of the role PAs play in catalytic process. The topics are subdivided into catalysis promoted by the PA rim/cavity, PA‐based nanomaterials, and PA‐based polymeric materials. To the best of our knowledge, this is the first overview on PA‐based catalysis. This Minireview not only summarizes the fabrications and applications of PAs in catalysis but also anticipates future research efforts in applying supramolecular hosts in catalysis.
Pillararenes have become increasingly popular since their first discovery in 2008 because of their rigid, capacious, and hydrophobic cavities as well as their exposed functional groups. This Minireview highlights three types of catalysis with pillararenes: 1) within the confined cavity or by attached pendent groups, 2) by nanomaterials featuring pillararenes in their architecture, and 3) by pillararene‐derived polymeric materials.
Failure mode and effect analysis (FMEA) is a prospective reliability analysis technique used in a wide range of industries for enhancing the safety and reliability of systems, products, processes, ...and services. However, the conventional FMEA method has been criticized for inherent drawbacks that limit effectiveness and applications. In this paper, a novel integrated FMEA model based on cloud model theory and hierarchical technique for order of preference by similarity to ideal solution (TOPSIS) method is developed to assess and rank the risk of failure modes. First, individual linguistic assessments of failure modes are converted into normal clouds. Then, FMEA team members' weights are calculated based on the subjective weighting information. Finally, the risk priority of failure modes is determined by using the cloud hierarchical TOPSIS. The newly proposed FMEA method combines the advantages of the cloud model in coping with fuzziness and randomness of linguistic assessments and the merits of hierarchical TOPSIS in solving complex decision making problems. Two empirical examples to illustrate the feasibility and effectiveness of the proposed FMEA are presented together with a comparison to existing methods.
NixCo2-xP nanoparticles with high electrical conductivity were prepared through hydrothermal method, they show high specific capacity and excellent rate capability.
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High electrical ...conductivity is a vital factor to improve electrochemical performance of energy storage materials. In this work, bimetallic nickel cobalt phosphides with high electrical conductivity and different Ni/Co molar ratios are directly fabricated via a simple hydrothermal method. The samples show uniform teeny nanoparticles morphology and excellent electrochemical performance. The NiCoP sample exhibits the most prominent specific capacity (571Cg−1 at 1Ag−1) and out-bound rate characteristic (72.8% capacity retention with a 20-fold increase in current densities), which can be attributed to the good crystallinity, larger specific surface area, and noteworthy intrinsic conductivity that convenient for fast electron transfer in active material and fleet reversible faradic reaction characteristics. Simultaneously, an optimal asymmetric supercapacitor based on NiCoP as positive and activated carbon as negative is assembled. It can achieve a high energy density of 32Whkg−1 (at a power density of 0.351kWkg−1) and prominent cycling stability with 91.8% initial capacity retention after 3000 cycles. It demonstrates that nickel cobalt phosphides are promising as energy storage materials. The study could also pave the way to explore a new class of bimetallic phosphides materials high electrical conductivity for electrochemical energy storage.
Many markets have historically been dominated by a small number of best-selling products. The Pareto principle, also known as the 80/20 rule, describes this common pattern of sales concentration. ...However, information technology in general and Internet markets in particular have the potential to substantially increase the collective share of niche products, thereby creating a longer tail in the distribution of sales. This paper investigates the Internet's "long tail" phenomenon. By analyzing data collected from a multichannel retailer, it provides empirical evidence that the Internet channel exhibits a significantly less concentrated sales distribution when compared with traditional channels. Previous explanations for this result have focused on differences in product availability between channels. However, we demonstrate that the result survives even when the Internet and traditional channels share exactly the same product availability and prices. Instead, we find that consumers' usage of Internet search and discovery tools, such as recommendation engines, are associated with an increase the share of niche products. We conclude that the Internet's long tail is not solely due to the increase in product selection but may also partly reflect lower search costs on the Internet. If the relationships we uncover persist, the underlying trends in technology portend an ongoing shift in the distribution of product sales.
This paper was accepted by Ramayya Krishnan, information systems.
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