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https://www.readbyqxmd.com/read/28527446/single-molecule-spin-orientation-control-by-an-electric-field
#1
Yachao Zhang
We report the effects of an electric field E on the spin orientations of nickelocene (Nc) deposited on the Cu surfaces by means of first-principles calculations. We employ the Hubbard-U corrected van der Waals density functional to take into account the strong correlation effects of the localized 3d electrons and the non-covalent binding involved in the molecule-surface coupling. We show that the deposited Nc molecule can switch between in-plane (in small E-field) and perpendicular magnetization (in large E-field)...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28527435/gauge-invariant-theory-for-super-high-resolution-raman-images
#2
Sai Duan, Guangjun Tian, Zhen Xie, Yi Luo
The use of a highly localized plasmonic field has enabled us to achieve sub-nanometer resolution of Raman images for single molecules. The inhomogeneous spatial distribution of plasmonic field has become an important factor that controls the interaction between the light and the molecule. We present here a gauge invariant interaction Hamiltonian (GIIH) to take into account the non-uniformity of the electromagnetic field distribution in the non-relativistic regime. The theory has been implemented for both resonant and nonresonant Raman processes within the sum-over-state framework...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28526925/polyphenolic-extract-attenuates-fatty-acid-induced-steatosis-and-oxidative-stress-in-hepatic-and-endothelial-cells
#3
Laura Vergani, Giulia Vecchione, Francesca Baldini, Elena Grasselli, Adriana Voci, Piero Portincasa, Pier Francesco Ferrari, Bahar Aliakbarian, Alessandro A Casazza, Patrizia Perego
PURPOSE: Phenolic compounds (PC) of virgin olive oil exert several biochemical and pharmacological beneficial effects. Some dietary PC seem to prevent/improve obesity and metabolic-related disorders such as non-alcoholic fatty liver disease (NAFLD). We investigated the possible effects of PC extracted from olive pomace (PEOP) and of the main single molecules present in the extract (tyrosol, apigenin, oleuropein, p-coumaric and caffeic acid) in protecting hepatocytes and endothelial cells against triglyceride accumulation and oxidative stress...
May 19, 2017: European Journal of Nutrition
https://www.readbyqxmd.com/read/28525955/imaging-and-manipulating-energy-transfer-among-quantum-dots-at-individual-dot-resolution
#4
Duc A Nguyen, Huy A Nguyen, Joseph W Lyding, Martin Gruebele
Many processes of interest in quantum dots involve charge or energy transfer from one dot to another. Energy transfer in films of quantum dots as well as between linked quantum dots has been demonstrated by luminescence shift, and the ultrafast time-dependence of energy transfer processes has been resolved. Bandgap variation among dots (energy disorder) and dot separation are known to play an important role in how energy diffuses. Thus it would be very useful if energy transfer could be visualized directly on a dot-by-dot basis among small clusters or within films of quantum dots...
May 19, 2017: ACS Nano
https://www.readbyqxmd.com/read/28525806/a-novel-porphyrin-based-molecular-probe-zntcppspm4-with-catalytic-stabilizing-and-chiroptical-diagnostic-power-towards-dna-b-z-transition
#5
Chiara M A Gangemi, Alessandro D'Urso, Gaetano A Tomaselli, Nina Berova, Roberto Purrello
In this work we have designed a new zinc(II) porphyrin with four spermines conjugate in the meso positions, meso-tetrakis-(4-carboxysperminephenyl)porphyrin, ZnTCPPSpm4) with the aim of acting as a chiroptical probe for the Z-form of DNA, a high energy transient conformation of DNA. In addition to monitor by Electronic Circular Dichroism chiroptical response the formation of Z-DNA in the presence of micromolar concentration of spermine, this porphyrin based molecular probe is also able to catalyze and stabilize this important DNA structure...
May 14, 2017: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/28524881/sub-nanometre-control-of-the-coherent-interaction-between-a-single-molecule-and-a-plasmonic-nanocavity
#6
Yao Zhang, Qiu-Shi Meng, Li Zhang, Yang Luo, Yun-Jie Yu, Ben Yang, Yang Zhang, Ruben Esteban, Javier Aizpurua, Yi Luo, Jin-Long Yang, Zhen-Chao Dong, J G Hou
The coherent interaction between quantum emitters and photonic modes in cavities underlies many of the current strategies aiming at generating and controlling photonic quantum states. A plasmonic nanocavity provides a powerful solution for reducing the effective mode volumes down to nanometre scale, but spatial control at the atomic scale of the coupling with a single molecular emitter is challenging. Here we demonstrate sub-nanometre spatial control over the coherent coupling between a single molecule and a plasmonic nanocavity in close proximity by monitoring the evolution of Fano lineshapes and photonic Lamb shifts in tunnelling electron-induced luminescence spectra...
May 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28524266/single-molecule-and-ensemble-diffusivities-in-individual-nanopores-with-spatially-dependent-mobility
#7
Julia Rybka, Jörg Kärger, Ulrich Tallarek
We investigate single-molecule and ensemble diffusivities in a silica nanopore with chemically modified surface by molecular dynamics simulations. Solutes with graded polarity (nonpolar ethylbenzene and moderately polar benzyl alcohol) are equilibrated with a 40:60 (v/v) water/acetonitrile solvent in a 10 nm pore, whose surface has been rendered hydrophobic by modification with alkyl chains. Simulations enable a detailed sampling of spatially dependent solvent and solute mobilities, which originate in a micro-heterogeneity induced by the surface modification...
May 19, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28523559/techniques-for-single-molecule-mrna-imaging-in-living-cells
#8
Kevin Czaplinski
Typical measurement of macromolecules in a biological sample typically averages the result over all the cells or molecules within the sample, and while these types of measurements provide very useful information, they completely miss heterogeneity among the components within the sample that could be a very important aspect of the sample's function. These techniques are also limited in their ability to examine intracellular spatial orientation of molecular activity, which is often a critical component to the regulation of biological processes, particularly in cells with unique spatial relationships, such as neurons...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28522818/efficient-modification-of-%C3%AE-dna-substrates-for-single-molecule-studies
#9
Yoori Kim, Armando de la Torre, Andrew A Leal, Ilya J Finkelstein
Single-molecule studies of protein-nucleic acid interactions frequently require site-specific modification of long DNA substrates. The bacteriophage λ is a convenient source of high quality long (48.5 kb) DNA. However, introducing specific sequences, tertiary structures, and chemical modifications into λ-DNA remains technically challenging. Most current approaches rely on multi-step ligations with low yields and incomplete products. Here, we describe a molecular toolkit for rapid preparation of modified λ-DNA...
May 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28518172/super-resolution-microscopy-with-dna-paint
#10
Joerg Schnitzbauer, Maximilian T Strauss, Thomas Schlichthaerle, Florian Schueder, Ralf Jungmann
Super-resolution techniques have begun to transform biological and biomedical research by allowing researchers to observe structures well below the classic diffraction limit of light. DNA points accumulation for imaging in nanoscale topography (DNA-PAINT) offers an easy-to-implement approach to localization-based super-resolution microscopy, owing to the use of DNA probes. In DNA-PAINT, transient binding of short dye-labeled ('imager') oligonucleotides to their complementary target ('docking') strands creates the necessary 'blinking' to enable stochastic super-resolution microscopy...
June 2017: Nature Protocols
https://www.readbyqxmd.com/read/28516950/high-conductance-values-in-%C3%AF-folded-molecular-junctions
#11
Marco Carini, Marta P Ruiz, Imanol Usabiaga, José A Fernández, Emilio J Cocinero, Manuel Melle-Franco, Ismael Diez-Perez, Aurelio Mateo-Alonso
Folding processes play a crucial role in the development of function in biomacromolecules. Recreating this feature on synthetic systems would not only allow understanding and reproducing biological functions but also developing new functions. This has inspired the development of conformationally ordered synthetic oligomers known as foldamers. Herein, a new family of foldamers, consisting of an increasing number of anthracene units that adopt a folded sigmoidal conformation by a combination of intramolecular hydrogen bonds and aromatic interactions, is reported...
May 18, 2017: Nature Communications
https://www.readbyqxmd.com/read/28516911/electrostatic-melting-in-a-single-molecule-field-effect-transistor-with-applications-in-genomic-identification
#12
Sefi Vernick, Scott M Trocchia, Steven B Warren, Erik F Young, Delphine Bouilly, Ruben L Gonzalez, Colin Nuckolls, Kenneth L Shepard
The study of biomolecular interactions at the single-molecule level holds great potential for both basic science and biotechnology applications. Single-molecule studies often rely on fluorescence-based reporting, with signal levels limited by photon emission from single optical reporters. The point-functionalized carbon nanotube transistor, known as the single-molecule field-effect transistor, is a bioelectronics alternative based on intrinsic molecular charge that offers significantly higher signal levels for detection...
May 18, 2017: Nature Communications
https://www.readbyqxmd.com/read/28514955/label-free-biosensing-of-salmonella-enterica-serovars-at-single-cell-level
#13
Bin Wang, Bosoon Park, Bingqian Xu, Yongkuk Kwon
BACKGROUND: The emerging nanotechnologies have greatly facilitated the development of label-free biosensors. The atomic force microscopy (AFM) has been used to study the molecular mechanism of the reactions for protein and aptamers. The surface plasmon resonance (SPR) have been used in fast detections of various pathogens such as bacteria. This study used both AFM and SPR to investigate the complex reactions between aptamers and outer membrane proteins (OMPs) on the surface of S. typhimurium...
May 17, 2017: Journal of Nanobiotechnology
https://www.readbyqxmd.com/read/28514843/single-cell-real-time-visualization-and-quantification-of-perylene-bioaccumulation-in-microorganisms
#14
Xin Jin, Xuejun Guo, Deshu Xu, Yanna Zhao, Xinghui Xia, Fan Bai
Bioaccumulation of perylene in Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was visualized and quantified in real time with high sensitivity at high temporal resolution. For the first time, single-molecule fluorescence microscopy (SMFM) with a microfluidic flow chamber and temperature control has enabled us to record the dynamic process of perylene bioaccumulation in single bacterial cells and examine the cell-to-cell heterogeneity. Although with identical genomes, individual E. coli cells exhibited a high degree of heterogeneity in perylene accumulation dynamics, as shown by the high coefficient of variation (C...
May 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28513712/charge-transport-in-c60-based-single-molecule-junctions-with-graphene-electrodes
#15
Susanne Leitherer, Pedro B Coto, Konrad Ullmann, Heiko B Weber, Michael Thoss
We investigate charge transport in C60-based single-molecule junctions with graphene electrodes employing a combination of density functional theory (DFT) electronic structure calculations and Landauer transport theory. In particular, the dependence of the transport properties on the conformation of the molecular bridge and the type of termination of the graphene electrodes is investigated. Furthermore, electron pathways through the junctions are analyzed using the theory of local currents. The results reveal, in agreement with previous experiments, a pronounced dependence of the transport properties on the bias polarity, which is rationalized in terms of the electronic structure of the molecule...
May 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/28512786/a-single-molecular-and-gate-operated-with-two-orthogonal-switching-mechanisms
#16
Na Zhang, Wai-Yip Lo, Anex Jose, Zhengxu Cai, Lianwei Li, Luping Yu
Single-molecular electronics is a potential solution to nanoscale electronic devices. While simple functional single-molecule devices such as diodes, switches, and wires are well studied, complex single-molecular systems with multiple functional units are rarely investigated. Here, a single-molecule AND logic gate is constructed from a proton-switchable edge-on gated pyridinoparacyclophane unit with a light-switchable diarylethene unit. The AND gate can be controlled orthogonally by light and protonation and produce desired electrical output at room temperature...
May 17, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28512753/serum-neurofilament-light-a-biomarker-of-neuronal-damage-in-multiple-sclerosis
#17
Giulio Disanto, Christian Barro, Pascal Benkert, Yvonne Naegelin, Sabine Schädelin, Antonella Giardiello, Chiara Zecca, Kaj Blennow, Henrik Zetterberg, David Leppert, Ludwig Kappos, Claudio Gobbi, Jens Kuhle
OBJECTIVE: Neurofilament light chains (NfL) are unique to neuronal cells, are shed to the CSF and are detectable at low concentrations in peripheral blood. Various diseases causing neuronal damage have resulted in elevated CSF concentrations. We explored the value of an ultrasensitive single-molecule array (Simoa) serum NfL (sNfL) assay in MS. METHODS: sNfL levels were measured in healthy controls (HC, n=254) and two independent MS cohorts: (1) cross-sectional with paired serum and CSF samples (n=142); (2) longitudinal with repeated serum sampling (n=246, median (IQR) follow-up 3...
May 16, 2017: Annals of Neurology
https://www.readbyqxmd.com/read/28511017/thermal-evolution-of-one-dimensional-iodine-chains
#18
Dingdi Wang, Haijing Zhang, William W Yu, Zikang Tang
In one-dimensional (1D) systems, the definition of three common states of matter (solid, liquid and gas) becomes obscure, because it has been theoretically predicted that a 1D system has no phase transition. Due to technical difficulty in tracking 1D thermal evolution, hardly any experimental evidence has demonstrated whether there exist these three states. Here we report Raman experimental observation that 1D iodine molecular chains formed inside the nano-sized channel undergo continuous transformation from chain structure to single molecules with increasing temperature, without having a sudden change as commonly observed in phase transition...
May 16, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28510311/rapid-microfluidic-dilution-for-single-molecule-spectroscopy-of-low-affinity-biomolecular-complexes
#19
Niels Zijlstra, Fabian Dingfelder, Bengt Wunderlich, Franziska Zosel, Stephan Benke, Daniel Nettels, Benjamin Schuler
To enable the investigation of low-affinity biomolecular complexes with confocal single-molecule spectroscopy, we have developed a microfluidic device that allows a concentrated sample to be diluted by up to five orders of magnitude within milliseconds, at the physical limit dictated by diffusion. We demonstrate the capabilities of the device by studying the dissociation kinetics and structural properties of low-affinity protein complexes using single-molecule two-color and three-color Förster resonance energy transfer (FRET)...
May 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28510054/design-and-development-of-genetically-encoded-fluorescent-sensors-to-monitor-intracellular-chemical-and-physical-parameters
#20
REVIEW
Arno Germond, Hideaki Fujita, Taro Ichimura, Tomonobu M Watanabe
Over the past decades many researchers have made major contributions towards the development of genetically encoded (GE) fluorescent sensors derived from fluorescent proteins. GE sensors are now used to study biological phenomena by facilitating the measurement of biochemical behaviors at various scales, ranging from single molecules to single cells or even whole animals. Here, we review the historical development of GE fluorescent sensors and report on their current status. We specifically focus on the development strategies of the GE sensors used for measuring pH, ion concentrations (e...
June 2016: Biophysical Reviews
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