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Chemical sensors have been essential components in recent years due to the gathering attention in environmental monitoring and healthcare. In this review, the authors comprehensively highlight recent progresses on the 1D chemiresistive-type sensors based on semiconductor metal oxides (SMOs) and optical-type sensors, which are prepared by electrospinning technique. In the part of chemiresistive-type sensors, diverse synthesis techniques for 1D SMO nanofibrous structure are presented with controlled microstructure and surface morphology. In addition, unique functionalization routes of emerging nanocatalysts encapsulated by bio-inspired templates are described for the next generation catalyst on the 1D SMO nanofibers (NFs). For the optical-type sensors, new classes of 1D NFs employing specific absorption and emission properties are introduced. In particular, diverse 1D NF-based colorimetric and fluorescence sensors as well as Raman and surface-enhanced Raman scattering sensors are covered in the view point of material preparation and optical sensing properties. Finally, the authors prospect future research directions to overcome current limitations and challenges to achieve high performance chemical sensors. [ABSTRACT FROM AUTHOR]

This study attempts to reconcile the two strands of research on the impacts of financial leverage on firm valuation. The prior literature has shown that financial leverage has a polysemous effect. In other words, it provides two opposing signals of firm performance (i.e., financial distress vs. a driver of positive change in a firm's prospects). Given that the effects of financial leverage are contradictory, we specify how these divergent signals appear and propose that there is a non-monotonic effect of financial leverage on firm valuation. The study also shows that marketing activities can be strategically implemented to tame these polysemous signals. Marketing activities are costly actions for a firm, especially one in an adverse environment with high leverage, and are rewarded in terms of firm valuation. Therefore, marketing activities can help reinforce the driver signal and alleviate the distress signal of financial leverage, thus increasing firm valuation. This study finds a U-shaped relationship between financial leverage and Tobin's q and a positive moderating effect of marketing intensity on the curvilinear relationship. [ABSTRACT FROM AUTHOR]

Conductive porous materials having a high surface reactivity offer great promise for a broad range of applications. However, a general and scalable synthesis of such materials remains challenging. In this work, the facile synthesis of catalytic metal nanoparticles (NPs) embedded in 2D metal–organic frameworks (MOFs) is reported as highly active and conductive porous materials. After the assembly of 2D conductive MOFs (C‐MOFs), i.e., Cu3(hexahydroxytriphenylene)2 [Cu3(HHTP)2], Pd or Pt NPs are functionalized within the cavities of C‐MOFs by infiltration of metal ions and subsequent reduction. The unique structure of Cu3(HHTP)2 with a cavity size of 2 nm confines the bulk growth of metal NPs, resulting in ultra‐small (≈2 nm) and well‐dispersed metal NPs loaded in 2D C‐MOFs. The Pd or Pt NPs‐loaded Cu3(HHTP)2 exhibits remarkably improved NO2 sensing performance at room temperature due to the high reactivity of catalytic metal NPs and the high porosity of C‐MOFs. The catalytic effect of Pd and Pt NPs on NO2 sensing of Cu3(HHTP)2, in terms of reaction rate kinetics and activation energy, is demonstrated. [ABSTRACT FROM AUTHOR]

Front Cover: The feature describes two different types of chemical sensors, i.e., chemiresistive type sensors and optical sensors. For the chemiresistive type sensors, electrical signals are modulated during the reaction with chemical gas species. On the other hand, distinctive color changes are occurred in the case of optical sensors after the reaction with chemical analytes. The feature is designed for the review paper about one‐dimensional nanofibrous sensing structures for chemiresistive type sensors and optical sensors. This is reported by Seon‐Jin Choi, Luana Persano, Andrea Camposeo, Ji‐Soo Jang, Won‐Tae Koo, Sang‐Joon Kim, Hee‐Jin Cho, Il‐Doo Kim and Dario Pisignano, in article number 1600569. [ABSTRACT FROM AUTHOR]