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• BINOL-based chiral organic emitters have been synthesized. • The molecules with benzoxazole moieties display aggregation induced emission properties. • The molecules with quinazolinone moieties exhibit acidochromic properties. • Compound 5 has specific aggregation-induced circular dichroism enhancement property. The development of chiral organic fluorescent molecules has attracted broad attention for their various optical applications. In this work, four pairs of chiral fluorescent molecules based on binaphthanol structure have been designed and synthesized. These molecules show blue fluorescent emission in organic solvents with good fluorescent quantum yields and large Stokes shifts. The molecules with benzoxazole moiety display aggregation-induced emission effect in methanol/water solutions, while molecules with quinazolinone moiety show aggregation-caused quenching properties. Moreover, compounds with quinazolinone moiety exhibit acidochromic properties in aqueous solution with different pH values, and their emission intensity are significantly enhanced in strongly acidic conditions. The chiral molecules generally have good circular dichroism intensity. Their R- and S- enantiomers show mirror-imaged circular dichroism curves. Further studies reveal that compound with mono quinazolinone moiety has specific aggregation-induced circular dichroism enhancement properties. This work provides a new strategy for obtaining chiral BINOL-based fluorescent molecules with unique optical properties. BINOL-based chiral organic emitters with benzoxazole or quinazolinone moieties have been synthesized. These molecules exhibit aggregation induced emission, acidochromic and chiral optical properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Chiral organic fluorescent materials have attracted broad attention for their application in various chiroptical devices. Helicenes possess special helical structure and unique optical properties, and have been utilized to develop chiral organic fluorescent materials with excellent chiroptical performance. However, the low luminescence efficiency of helicene-based chiral fluorescent materials in solid state limits their practical applications. In this work, chiral organic fluorescent emitters with helicene moiety have been developed from binaphthanol structure. These BINOL [4]helicene compounds display aggregation-enhanced emission properties, and have strong blue emission in solid state with fluorescent quantum yield up to 0.67. The DFT calculation reveals that these compounds have highly twisted molecular structures. Thus, the excellent fluorescent properties in solid state could be aroused by the highly contorted molecular structures, which could limit the π-π stacking of adjacent molecules in solid state. The enantiomers of these compounds show strong Cotton effects in circular dichroism spectra, and the molecules with 4-methoxy phenyl moiety exhibit circularly polarized luminescence properties. Highly twisted BINOL- [4]helicene hybrids have been synthesized, which have strong fluorescent emission in solid state and chiral optical properties. [Display omitted] • Chiral binol-[4]helicene hybrids have been synthesized. • These molecules display aggregation-enhanced emission properties. • These molecules show strong fluorescent emission in solid state. • Compound 6 exhibits circularly polarized luminescence property. [ABSTRACT FROM AUTHOR]

A paper-based sensor has been developed for light-up detection of amine vapors. This potable sensor shows high sensitivity, low detection limit, and good selectivity toward amine vapors. The sensor can be utilized for food spoilage detection and fluorescent security ink. [Display omitted] • A portable fluorescent sensor has been prepared for turn-on detection of amine vapors. • The sensor shows high sensitivity, low detection limit, and good selectivity for amine vapor detection. • The sensor can be applied for food spoilage detection and fluorescent security ink. Amines are widely used in many fields including agriculture, dyes, medicine and food processing. However, volatile amine vapors could initiate acute and serious damage to human bodies. Thus, highly efficient detection of volatile amine vapors has great importance for academic research as well as practical application. In this work, a turn-on type fluorescent sensor BZCO has been developed, which could be used to detect volatile amine vapors. The portable BZCO sensor can be easily prepared through immersing filter paper into its CH 2 Cl 2 solution and then evaporating it to dryness. This paper-based amine vapor sensor exhibits high sensitivity with a relatively low detection limit at 3.82 ppm. It also has good selectivity for discriminating amine vapors from volatile organic solvents. The detection mechanism has been confirmed by UV–vis spectral analysis. The practical applications of this paper-based BZCO sensor, such as detection of food spoilage and fluorescent security ink, have been investigated. This work has developed a new fluorescent sensor BZCO , which has broad applications in various fields, including amine gas detection, security and anti-counterfeiting materials. [ABSTRACT FROM AUTHOR]

A simple and convenient silver-catalyzed multicomponent strategy for the construction of highly functionalized γ-carbonyl-α-amino acid derivatives has been developed under mild conditions. • Multicomponent tandem reactions for synthesis of γ-carbonyl-α-amino acid derivatives. • Atom and step-economy. • Mild condition. • High reaction efficiency. Silver-catalyzed multicomponent strategy for the construction of highly functionalized γ-carbonyl-α-amino acid derivatives has been developed under mild conditions, in which various γ-carbonyl-α-amino acid derivatives were obtained in moderate to excellent yields. Preliminary mechanistic studies suggested that silver-catalyzed A 3 -coupling reaction and alkyne hydration process were accomplished in a simple operation. [ABSTRACT FROM AUTHOR]

Growing evidence suggests that liana competition with trees is threatening the global carbon sink by slowing the recovery of forests following disturbance. A recent theory based on local and regional evidence further proposes that the competitive success of lianas over trees is driven by interactions between forest disturbance and climate. We present the first global assessment of liana–tree relative performance in response to forest disturbance and climate drivers. Using an unprecedented dataset, we analysed 651 vegetation samples representing 26,538 lianas and 82,802 trees from 556 unique locations worldwide, derived from 83 publications. Results show that lianas perform better relative to trees (increasing liana‐to‐tree ratio) when forests are disturbed, under warmer temperatures and lower precipitation and towards the tropical lowlands. We also found that lianas can be a critical factor hindering forest recovery in disturbed forests experiencing liana‐favourable climates, as chronosequence data show that high competitive success of lianas over trees can persist for decades following disturbances, especially when the annual mean temperature exceeds 27.8°C, precipitation is less than 1614 mm and climatic water deficit is more than 829 mm. These findings reveal that degraded tropical forests with environmental conditions favouring lianas are disproportionately more vulnerable to liana dominance and thus can potentially stall succession, with important implications for the global carbon sink, and hence should be the highest priority to consider for restoration management. [ABSTRACT FROM AUTHOR]

Highly planar organic emitters have been developed from 4-styrylbenzonitrile structure, which show strong AIE properties and deep blue emission in solid state with good to excellent fluorescence quantum efficiency. [Display omitted] • 4-Styrylbenzonitrile derivatives are synthesized. • These planar fluorophores show strong AIE properties. • These compounds are efficient deep blue emitters in solid states with high quantum yields. Organic fluorescent molecules with π-conjugated system have shown great importance in numerous applications including bioimaging and optoelectronics. Planar aggregation-induced emissive (AIE) organic compounds with efficient solid-state luminescence are rarely developed and urgently needed in various applications. In this work, highly planar 4-styrylbenzonitrile derivatives have been synthesized. Most of these compounds show strong AIE properties with hundred-fold fluorescent enhancement. Moreover, these molecules are deep blue emissive in solid state, exhibiting good to excellent fluorescence quantum efficiency. The single crystal analysis shows that adjacent molecules could form special J-type aggregation. The intramolecular rotations are efficiently restricted by various noncovalent interactions. These molecular arrangements could be essential for the observed strong emission in aggregated and solid state. This work has paved a new path to efficient AIE-active organic emitters with highly planar conformations from 4-styrylbenzonitrile structure. [ABSTRACT FROM AUTHOR]

Abstract: We prove several basic properties for difference ascending chains, including a necessary and sufficient condition for an ascending chain to be the characteristic set of its saturation ideal and a necessary and sufficient condition for an ascending chain to be the characteristic set of a reflexive prime ideal. Based on these properties, we propose an algorithm to decompose the zero set of a finite set of difference polynomials into the union of zero sets of certain ascending chains. This decomposition algorithm is implemented and used to solve the perfect ideal membership problem, and to prove certain difference identities automatically. [Copyright &y& Elsevier]

The design and exploration of efficient organic fluorophores have attracted significant scientific interest for their various potential applications. As blue fluorescent materials are essential for the achievement of a full-color display and white emission, the development of new efficient organic blue-emitting materials is of great importance. In this work, we found that simple organic molecules 2-aryloxybenzo[d]oxazoles could act as novel organic fluorophores with special AIE properties and efficient blue fluorescent emission in the solid states. Compounds 3 and 4 possess moderately high quantum yields at 10.3% and 11.4%, respectively. The CIE coordinates indicate that most of these compounds are deep-blue emitters. The single crystal structure of compound 3 shows that it has a twisted V-shape molecular structure with J-type aggregation. Noncovalent interactions widely exist in the crystal structures, while π-π stacking interactions are not observed between adjacent aromatic rings. The special fluorescent properties of these new emitters could ascribe to the unique molecular packing mode in the crystal structure. This work provides a new strategy to access organic solid-state fluorophores with deep-blue emission. Simple organic molecules (2-aryloxybenzo[d]oxazoles) act as novel organic fluorophores with special AIE properties and efficient deep blue fluorescent emission in the solid states. Image 1 • 2-Aryloxybenzo[d]oxazoles derivatives are designed and synthesized. • These fluorophores show special AIE properties. • These compounds exhibit efficient deep blue emission in solid states. [ABSTRACT FROM AUTHOR]

Organic fluorescent materials have been widely used in various fields including visualization of latent fingerprints and imaging of lysosomes. High-performance organic fluorescent molecules based on simple molecular structures are still limited and highly demanded for high-definition and high-contrast imaging of latent fingerprints and lysosomes. In this work, two organic fluorescent molecules (DANPAN and DANBEN) were developed based on dimethylamino naphthalenyl phenylethene structure. These two molecules have quite different fluorescent properties, and the position of cyano group significantly affects the optical properties of these dimethylamino naphthalenyl phenylethene derivatives. Compound DANPAN shows strong yellow emission in solid state, while compound DANBEN has strong fluorescent emission in organic solutions. In addition to these differences, both compounds have large Stokes shifts and positive solvatochromic properties. Further studies showed that these compounds could be used to display latent fingerprints on various substrate surfaces. The obtained fingerprint images have excellent contrast and high resolution. It is also found that these molecules could specifically stain lysosomes in living cell within short incubation time. This work provides a series of new high-performance organic fluorescent materials with diverse applications. Highly emissive dimethylamino naphthalenyl phenylethene derivatives have been synthesized, which show large Stokes shifts and positive solvatochromic properties. These compounds could be applied for visualization of latent fingerprints and specific localization of lysosomes in living cell imaging. [Display omitted] • Two dimethylamino naphthalenyl phenylethene derivatives are synthesized. • These molecules show large Stokes shifts and positive solvatochromic properties. • These compounds could be applied for visualization of latent fingerprints on various substrate surfaces. • These molecules could be used for specific localization of lysosomes in living cell imaging. [ABSTRACT FROM AUTHOR]

High-voltage dc/dc converters play an important role in HVDC grids. Isolated modular dc/dc converters (IMDCCs) based on modular multilevel converter technology provide a good solution to high-voltage applications. In order to reduce the size of the system, the IMDCC is required to be operated with a high ac-link frequency, but this will lead to increased switching loss and thus degraded efficiency. This paper proposes a soft-switching operation scheme for such an IMDCC. In this scheme, a quasi-square-wave (QSW) modulation method is employed, where the chain-links generate quasi-square terminal voltages with reduced dv/dt. With such chain-link terminal voltages, the arm currents which provide good condition for the soft-switching operation of the QSW-IMDCC can be obtained. Since soft switching can be achieved for the power switches, the proposed scheme will suffer less switching loss, thus improving the efficiency of the converter. Moreover, a capacitor voltage-balancing control strategy is proposed. This strategy does not need any arm current sensors, thus reducing the cost. The proposed soft-switching operation scheme and capacitor voltage-balancing control strategy are verified by the simulation results. [ABSTRACT FROM PUBLISHER]