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Dazhuang Xu, Meiying Liu, Hui Zou, Jianwen Tian, Hongye Huang, Qing Wan, Yanfeng Dai, Yuanqing Wen, Xiaoyong Zhang, Yen Wei
Fluorescence probes play a crucial role in optical imaging for visualization of complex biological processes. As compared with conventional organic fluorogens, the probes with aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) characteristics show significant advantages in high quantum yield at concentrated and aggregated state, large Stokes shift and low cytotoxicity. However, the synthesis of AIE-active fluorescent probes through the ESIPT mechanism has received only very limited attention...
November 1, 2017: Talanta
Dayana B Bittar, David S M Ribeiro, Ricardo N M J Páscoa, José X Soares, S Sofia M Rodrigues, Rafael C Castro, Leonardo Pezza, Helena R Pezza, João L M Santos
Semiconductor quantum dots (QDs) have demonstrated a great potential as fluorescent probes for heavy metals monitoring. However, their great reactivity, whose tunability could be difficult to attain, could impair selectivity yielding analytical results with poor accuracy. In this work, the combination in the same analysis of multiple QDs, each with a particular ability to interact with the analyte, assured a multi-point detection that was not only exploited for a more precise analyte discrimination but also for the simultaneous discrimination of multiple mutually interfering species, in the same sample...
November 1, 2017: Talanta
Jingjing Jiang, Pengfei Gao, Yan Zhang, Guomei Zhang, Ying Zhou, Chuan Dong, Shaomin Shuang
Herein, we demonstrate a straightforward synthesis of fluorescent gold nanoclusters (AuNCs), employing 2-Mercapto-4-methyl-5-thiazoleacetic acid (MMTA) as a reducing and protecting agent by a rapid one-pot synthesis method with a short time of 20min. The as-synthesized MMTA-AuNCs exhibited bright blue emission with a strong peak centered at 430nm and the quantum yield (QY) was evaluated to be 4.0%. Based on the fluorescence quenching mechanism of a surface chelating reaction between MMTA and ferric ion (Fe(3+)), the MMTA-AuNCs were exploited as a fluorescence sensor for sensitive and selective detection of Fe(3+)...
November 1, 2017: Talanta
Yehan Yan, Kui Zhang, Huan Yu, Houjuan Zhu, Mingtai Sun, Tasawar Hayat, Ahmed Alsaedi, Suhua Wang
Hydrogen sulfide is a toxic and flammable gaseous pollutant often emitted to air as a by-product of water supply, chemical, petroleum and coal industries. It can be transferred into sulfur dioxide in the air under some meteorologic conditions. Herein, we report a novel ratiometric fluorescence method for hydrogen sulfide based on silver nanoclusters and quantum dots. The silver nanoclusters have been self-assemblied onto the surface of silica spheres, which are embedded with red fluorescent quantum dots, to form a dual-emissive nanohybrid...
November 1, 2017: Talanta
Mumei Han, Liping Wang, Siheng Li, Liang Bai, Yunjie Zhou, Yue Sun, Hui Huang, Hao Li, Yang Liu, Zhenhui Kang
The surface functionalization will introduce additional functional groups on carbon dots (CDs) surface and then enrich the properties of CDs. Here, we show the various surface functionalized CDs (-COOH, -OH, -SH, -NH2, etc, named as NS-CDs) were synthesized with fascinating features, including high quantum efficiency (38.9%), long-term stability and good biocompatibility. Notably, it can serve as multifunction fluorescent probe in sensing system, including label-free detections in hydrogen peroxide (H2O2) with a wide linear range (1...
November 1, 2017: Talanta
Majid Arvand, Shiva Hemmati
The goal of this study was to develop an electroanalytical method for the simultaneous determination of steroid hormones for the first time. The key factor in the electrochemical methods is the choice of suitable electrode materials. For this purpose, graphene quantum dots (GQDs) doped poly(sulfosalicylic acid) (PSSA) was immobilized on a glassy carbon electrode (GCE). Apart from exhibition strong and stable electrocatalytic response towards estradiol (E2) and progesterone (P4), the proposed sensor was able to distinguish two hormone's oxidation peaks clearly...
November 1, 2017: Talanta
Zhouyang Li, Yiwen Yang, Yanbo Zeng, Jianbo Wang, Haiqing Liu, Longhua Guo, Lei Li
This paper reports novel imidazole fluorescent poly(ionic liquid) nanoparticles (FPILNs) of poly(1-[(4-methyphenyl)methyl]-3-vinyl-imidazolium bromide (poly([MVI]Br) for selective and sensitive determination of pyrogallol. An imidazole ionic liquid of 1-[(4-methyphenyl)methyl]-3-vinyl-imidazolium bromide ([MVI]Br) was synthesized and used as the only monomer to obtain poly([MVI]Br) possessing phenyl fluorophores using a radical polymerization technique. The obtained poly([MVI]Br) can form nanoparticles in water...
November 1, 2017: Talanta
Bo Chen, Roald Hoffmann, Roberto Cammi
This Review brings a new perspective to the study of chemical reactions in compressed fluid media. We begin by reviewing the substantial insight gained from more than 50 years of experimental studies on organic reactions in solution under pressure. These led to a proper estimation of the critical roles of volume of activation (Δ(≠) V) and reaction volume (ΔV) in understanding pressure effect on rates and equilibria of organic reactions. A recently developed computational method, the XP-PCM (extreme pressure polarizable continuum model) method, capable of carrying out quantum mechanical calculations of reaction pathways of molecules under pressure, is introduced...
July 24, 2017: Angewandte Chemie
Lihong Wang, Jingfang He, Qing Yang, Xiaodong Li, Haiyan Wei, David D Y Chen, Xiaohua Huang
Vitronectin-like protein (VN) is widely found outside plant plasma membranes. The VN molecular surface contains a large number of active groups that combine strongly with rare earth elements (REEs), which means that VN is a preferential binding target for REEs exhibiting their toxic effects, but the toxicological mechanism remains unknown. This study used transmission electron microscopy, circular dichroism, fluorescence spectrometry, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, and calculational chemistry (homology modeling, molecular dynamics simulation and quantum chemical calculation) to preliminarily investigate the effect of lanthanum [La(III)] as an REE, on the structure of VN and its toxicological mechanism...
July 21, 2017: Ecotoxicology and Environmental Safety
Amit Kumar Samanta, Pujarini Banerjee, Biman Bandyopadhyay, Prasenjit Pandey, Tapas Chakraborty
Matrix isolation infrared spectra of a weak C-H•••O hydrogen bonded complex between the keto-enol form of 1,2-cyclohexanedione (HCHD) and chloroform have been measured. The spectra reveal that the intramolecular O-H•••O H-bond of HCHD is weakened as a result of complex formation, manifesting in prominent blue shift (~23 cm-1) of the νO-H band and red shifts (~7 cm-1) of νC=O bands of the acceptor (HCHD). The νC-H band of donor CHCl3 undergoes a large red shift of ~33 cm-1. Very similar spectral effects are also observed for formation of the complex in CCl4 solution at room temperature...
July 24, 2017: Journal of Physical Chemistry. A
Akos Banyasz, Lara Martínez-Fernández, Clémence Balty, Marion Perron, Thierry Douki, Roberto Improta, Dimitra Markovitsi
Telomeres, which are involved in cell division, carcinogenesis, and aging and constitute important therapeutic targets, are prone to oxidative damage. This propensity has been correlated with the presence of guanine-rich sequences, capable of forming four-stranded DNA structures (G-quadruplexes). Here, we present the first study on oxidative damage of human telomere G-quadruplexes without mediation of external molecules. Our investigation has been performed for G-quadruplexes formed by folding of GGG(TTAGGG)3 single strands in buffered solutions containing Na(+) cations (TEL21/Na(+))...
July 24, 2017: Journal of the American Chemical Society
Jinfeng Liu, Xiao He
Accurate prediction of physicochemical properties of ionic liquids (ILs) is of great significance to understand and design novel ILs with unique properties. This study employed the electrostatically embedded generalized molecular fractionation (EE-GMF) method for accurate energy calculation of IL clusters. The accuracy and efficiency of the EE-GMF method are systematically assessed at different ab initio levels (including HF, DFT and MP2) with diverse basis sets. With the fixed charge model for the embedding field, the deviations of the EE-GMF approach from conventional full system calculations are within 2...
July 24, 2017: Physical Chemistry Chemical Physics: PCCP
Yi Liu, Jicheng Duan, Fen Qi, Dan Tian, Xiaoqing Wang, Zhipeng Liu, Wei Huang
A new family of BODIPY dyes (PPB1-4) based on the pyridine-pyrimidine hybrid structure has been synthesized. These dyes show high cyan fluorescence in hexane with quantum yields (Φf) ranging from 0.33 to 0.90. Interestingly, moderate fluorescence of PPB1-4 is observed in the solid state (Φf, 0.11-0.26). X-ray structure analysis demonstrates that H-aggregation should be responsible for the red-shifted and quenched emission in the solid state. Moreover, PPB1-4 show high contrast and reversible mechanochromic fluorescence based on the proposed mechanism of mechanical stimuli triggered dimer dissolution and formation...
July 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Duy Khanh Nguyen, Yu-Tsung Lin, Shih-Yang Lin, Yu-Huang Chiu, Ngoc Thanh Thuy Tran, Ming Fa-Lin
The feature-rich electronic and magnetic properties of fluorine-doped graphene nanoribbons are investigated by the first-principles calculations. They arise from the cooperative or competitive relations among the significant chemical bonds, finite-size quantum confinement and edge structure. There exist C-C, C-F, and F-F bonds with multi-orbital hybridizations. Fluorine adatoms can create p-type metals or concentration- and distribution-dependent semiconductors, depending on whether the π bonding is seriously suppressed by the top-site chemical bonding...
July 24, 2017: Physical Chemistry Chemical Physics: PCCP
I G Grosu, M I Rednic, M Miclăuş, I Grosu, A Bende
The nature of intermolecular interactions in different molecular crystal configurations formed by pyridinium cations, chloride or bromide anions as well as β-hexachlorocyclohexane (β-HCH) molecules has been investigated using high level ab initio quantum chemistry methods. Several molecular subsystems taken from the crystal unit cell were considered and their supramolecular energy stability was analyzed in detail using high level density-fitting local electron correlation (DF-LMP2 and DF-LCCSD(T)) methods together with the aug-cc-pVTZ basis set...
July 24, 2017: Physical Chemistry Chemical Physics: PCCP
Hasan Mohammed Abdullah, Ben Van Duppen, Mohammad Zarenia, Hocine Bahlouli, Francois M Peeters
Bilayer graphene can exhibit deformations such that the two graphene sheets are locally detached from each other resulting in a structure consisting of domains with different van der Waals inter-layer coupling. Here we investigate how the presence of these domains affect the transport properties of bilayer graphene. We derive analytical expressions for the transmission probability, and the corresponding conductance, across walls separating different inter-layer coupling domains. We find that the transmission can exhibit a valley-dependent layer asymmetry and that the domain walls have a considerable effect on the chiral tunnelling properties of the charge carriers...
July 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Yiming Zhou, Li-Dong Zhao
Given that more than two thirds of all energy is lost, mostly as waste heat, in utilization processes worldwide, thermoelectric materials, which can directly convert waste heat to electricity, provide an alternative option for optimizing energy utilization processes. After the prediction that superlattices may show high thermoelectric performance, various methods based on quantum effects and superlattice theory have been adopted to analyze bulk materials, leading to the rapid development of thermoelectric materials...
July 24, 2017: Advanced Materials
S Chick, N Stavrias, K Saeedi, B Redlich, P T Greenland, G Matmon, M Naftaly, C R Pidgeon, G Aeppli, B N Murdin
Superposition of orbital eigenstates is crucial to quantum technology utilizing atoms, such as atomic clocks and quantum computers, and control over the interaction between atoms and their neighbours is an essential ingredient for both gating and readout. The simplest coherent wavefunction control uses a two-eigenstate admixture, but more control over the spatial distribution of the wavefunction can be obtained by increasing the number of states in the wavepacket. Here we demonstrate THz laser pulse control of Si:P orbitals using multiple orbital state admixtures, observing beat patterns produced by Zeeman splitting...
July 24, 2017: Nature Communications
Fabian Steinlechner, Sebastian Ecker, Matthias Fink, Bo Liu, Jessica Bavaresco, Marcus Huber, Thomas Scheidl, Rupert Ursin
Quantum entanglement is a fundamental resource in quantum information processing and its distribution between distant parties is a key challenge in quantum communications. Increasing the dimensionality of entanglement has been shown to improve robustness and channel capacities in secure quantum communications. Here we report on the distribution of genuine high-dimensional entanglement via a 1.2-km-long free-space link across Vienna. We exploit hyperentanglement, that is, simultaneous entanglement in polarization and energy-time bases, to encode quantum information, and observe high-visibility interference for successive correlation measurements in each degree of freedom...
July 24, 2017: Nature Communications
Xian-Wu Hua, Yan-Wen Bao, Zhan Chen, Fu-Gen Wu
We prepare for the first time a novel type of fluorescent carbon quantum dot (or carbon dot, CD) with intrinsic mitochondrial targeting ability by a one-step hydrothermal treatment of chitosan, ethylenediamine and mercaptosuccinic acid. The as-prepared CDs can realize mitochondrial imaging and mitochondria-targeted photodynamic cancer therapy without further modifications of other mitochondriotropic ligands (such as triphenylphosphine, TPP). Currently, many commercial mitochondrial probes suffer from the lack of modifiable groups, poor photostability, short tracking time, high cost and/or complicated staining procedures, which severely limit their applications in live-cell mitochondrial imaging...
July 24, 2017: Nanoscale
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