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Quantum biology

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https://www.readbyqxmd.com/read/28230915/a-singlet-oxygen-generating-agent-by-chirality-dependent-plasmonic-shell-satellite-nanoassembly
#1
Fengli Gao, Maozhong Sun, Wei Ma, Xiaoling Wu, Liqiang Liu, Hua Kuang, Chuanlai Xu
Photodynamic therapy (PDT) agent, which generates singlet oxygen ((1) O2 ) under light, has attracted significant attention for its broad biological and medical applications. Here, DNA-driven shell-satellite (SS) gold assemblies as chiral photosensitizers are first fabricated. The chiral plasmonic nanostructure, coupling with cysteine enantiomers on its surface, exhibits intense chiroplasmonic activities (-40.2 ± 2.6 mdeg) in the visible region. These chiral SS nanoassemblies have high reactive oxygen species generating efficiency under circular polarized light illumination, resulting in a (1) O2 quantum yield of 1...
February 23, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28228525/chirality-induced-spin-polarization-places-symmetry-constraints-on-biomolecular-interactions
#2
Anup Kumar, Eyal Capua, Manoj K Kesharwani, Jan M L Martin, Einat Sitbon, David H Waldeck, Ron Naaman
Noncovalent interactions between molecules are key for many biological processes. Necessarily, when molecules interact, the electronic charge in each of them is redistributed. Here, we show experimentally that, in chiral molecules, charge redistribution is accompanied by spin polarization. We describe how this spin polarization adds an enantioselective term to the forces, so that homochiral interaction energies differ from heterochiral ones. The spin polarization was measured by using a modified Hall effect device...
February 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28222263/reaction-mechanism-of-covalent-modification-of-phosphatidylethanolamine-lipids-by-reactive-aldehydes-4-hydroxy-2-nonenal-and-4-oxo-2-nonenal
#3
Katarina Vazdar, Danijela Vojta, Davor Margetić, Mario Vazdar
4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) are biologically important reactive aldehydes formed during oxidative stress in phospholipid bilayers. They are highly reactive species due to presence of several reaction centers and can react with amino acids in peptides and proteins, as well as phosphoethanolamine (PE) lipids, thus modifying their biological activity. The aim of this work is to study in a molecular detail the reactivity of HNE and ONE towards PE lipids in a simplified system containing only lipids and reactive aldehydes in dichloromethane as an inert solvent...
February 21, 2017: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/28221751/molecular-engineering-and-design-of-semiconducting-polymer-dots-with-narrow-band-near-infrared-emission-for-in-vivo-biological-imaging
#4
Chi-Shiang Ke, Chia-Chia Fang, Jia-Ying Yan, Po-Jung Tseng, Joseph R Pyle, Chuan-Pin Chen, Shu-Yi Lin, Jixin Chen, Xuanjun Zhang, Yang-Hsiang Chan
This article describes the design and synthesis of donor-bridge-acceptor-based semiconducting polymer dots (Pdots) that exhibit narrow-band emissions, ultrahigh brightness, and large Stokes shifts in the near-infrared (NIR) region. We systematically investigated the effect of π-bridges on the fluorescence quantum yields of the donor-bridge-acceptor-based Pdots. The Pdots could be excited by a 488 or 532 nm laser and have a high fluorescence quantum yield of 33% with a Stokes shift of more than 200 nm. The emission full width at half-maximum of the Pdots can be as narrow as 29 nm, about 2...
February 23, 2017: ACS Nano
https://www.readbyqxmd.com/read/28220770/hidden-topological-constellations-and-polyvalent-charges-in-chiral-nematic-droplets
#5
Gregor Posnjak, Simon Čopar, Igor Muševič
Topology has an increasingly important role in the physics of condensed matter, quantum systems, material science, photonics and biology, with spectacular realizations of topological concepts in liquid crystals. Here we report on long-lived hidden topological states in thermally quenched, chiral nematic droplets, formed from string-like, triangular and polyhedral constellations of monovalent and polyvalent singular point defects. These topological defects are regularly packed into a spherical liquid volume and stabilized by the elastic energy barrier due to the helical structure and confinement of the liquid crystal in the micro-sphere...
February 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28220440/quantum-probability-ranking-principle-for-ligand-based-virtual-screening
#6
Mohammed Mumtaz Al-Dabbagh, Naomie Salim, Mubarak Himmat, Ali Ahmed, Faisal Saeed
Chemical libraries contain thousands of compounds that need screening, which increases the need for computational methods that can rank or prioritize compounds. The tools of virtual screening are widely exploited to enhance the cost effectiveness of lead drug discovery programs by ranking chemical compounds databases in decreasing probability of biological activity based upon probability ranking principle (PRP). In this paper, we developed a novel ranking approach for molecular compounds inspired by quantum mechanics, called quantum probability ranking principle (QPRP)...
February 20, 2017: Journal of Computer-aided Molecular Design
https://www.readbyqxmd.com/read/28219723/the-protective-effects-of-resveratrol-h2s-and-thermotherapy-on-the-cell-apoptosis-induced-by-cdte-quantum-dots
#7
Tianshu Wu, Qingling Zhan, Ting Zhang, Shengjun Ang, Jiali Ying, Keyu He, Shihan Zhang, Yuying Xue, Meng Tang
Quantum dots (QDs) could be used in the field of biology and medicine as excellent nano-scale fluorescent probes due to their unique optical properties, but the adverse effects of QDs are always the obstruction for its usage in living organisms. In this study, we observed that CdTe QDs exposure decreased the cell viability while increased the apoptosis rates in the L929 cells. Apart from QD-induced oxidative stress indicated by excessive ROS generation, three signal transductions, including Akt, p38 and JNK, played important roles on the regulation of cell apoptosis by CdTe QDs exposure as well...
February 17, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/28212489/direct-single-enzyme-biomineralization-of-catalytically-active-ceria-and-ceria-zirconia-nanocrystals
#8
Christopher D Curran, Li Lu, Yue Jia, Christopher J Kiely, Bryan W Berger, Steven McIntosh
Biomineralization is an intriguing approach to the synthesis of functional inorganic materials for energy applications whereby biological systems are engineered to mineralize inorganic materials and control their structure over multiple length scales under mild reaction conditions. Herein we demonstrate a single enzyme mediated biomineralization route to synthesize crystalline, catalytically active, quantum confined ceria (CeO2-x) and ceria-zirconia (Ce1-yZryO2-x) nanocrystals for application as environmental catalysts...
February 17, 2017: ACS Nano
https://www.readbyqxmd.com/read/28198894/stripping-off-hydrogens-in-imidazole-triggered-by-the-attachment-of-a-single-electron
#9
A Ribar, K Fink, Z Li, S Ptasińska, I Carmichael, L Feketeová, S Denifl
Imidazole [C3H4N2] is ubiquitous in nature as an important biological building block of amino acids, purine nucleobases or antibiotics. In the present study, dissociative electron attachment to imidazole shows low energy shape resonances at 1.52 and 2.29 eV leading to the most abundant dehydrogenated anion [imidazole - H](-) through dehydrogenation at the N1 position. All the other anions formed exhibit core excited resonances observed dominantly at similar electron energies of ∼7 and 11 eV, suggesting an initial formation through two temporary negative ion states...
February 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28196324/delivery-of-liposomal-quantum-dots-via-monocytes-for-imaging-of-inflamed-tissue
#10
Gil Aizik, Nir Waiskopf, Majd Agbaria, Yael Levi-Kalisman, Uri Banin, Gershon Golomb
Quantum dots (QDs), semiconductor nanocrystals, are fluorescent nanoparticles of growing interest as an imaging tool of a diseased tissue. However, a major concern is their biocompatibility, cytotoxicity, and fluorescence instability in biological milieu, impeding their use in biomedical applications, in general, and for inflammation imaging, in particular. In addition, for an efficient fluorescent signal at the desired tissue, and avoiding systemic biodistribution and possible toxicity, targeting is desired...
February 20, 2017: ACS Nano
https://www.readbyqxmd.com/read/28194871/engineering-of-optically-encoded-microbeads-with-fret-free-spatially-separated-quantum-dot-layers-for-multiplexed-assays
#11
Igor Nabiev, Regina S Bilan, Viktor A Krivenkov, Mikhail A Berestovoy, Anton Efimov, Igor I Agapov, Pavel S Samokhvalov, Alyona V Sukhanova
Quantum dot (QD)-encoded microbeads are emerging for multiplexed analysis of biological markers. Quantitative encoding of the microbeads prepared with the different concentrations of QDs of different colors suffers from the resonance energy transfer from the QDs fluorescing at the shorter wavelengths to the QDs fluorescing at the longer wavelengths. Here, we have used the layer-by-layer deposition technique to spatially separate QDs of different colors with several polymer layers, so that the distance between them would be larger than the Förster energy transfer radius...
February 13, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28192669/benchmarking-qm-mm-methods-on-the-thymidylate-synthase-catalyzed-hydride-transfer
#12
Katarzyna Świderek, Kemel Arafet, Amnon Kohen, Vicent Moliner
Given the ubiquity of hydride-transfer reactions in enzyme-catalyzed processes, identifying the appropriate computational method for evaluating such biological reactions is crucial to perform theoretical studies of these processes. In this paper, the hydride-transfer step catalyzed by thymidylate synthase (TSase) is studied by examining hybrid QM/MM potentials via multiple semiempirical methods and the M06-2X hybrid density functional. Calculations of protium and tritium transfer in these reactions across a range of temperatures allowed calculation of the temperature dependence of kinetic isotope effects (KIE)...
February 13, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28191931/laser-synthesis-and-processing-of-colloids-fundamentals-and-applications
#13
Dongshi Zhang, Bilal Gökce, Stephan Barcikowski
Driven by functionality and purity demand for applications of inorganic nanoparticle colloids in optics, biology, and energy, their surface chemistry has become a topic of intensive research interest. Consequently, ligand-free colloids are ideal reference materials for evaluating the effects of surface adsorbates from the initial state for application-oriented nanointegration purposes. After two decades of development, laser synthesis and processing of colloids (LSPC) has emerged as a convenient and scalable technique for the synthesis of ligand-free nanomaterials in sealed environments...
February 13, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28185452/organic-nanowire-sio2-core-shell-microlasers-with-highly-polarized-and-narrow-emissions-for-biological-imaging
#14
Changfu Feng, Zhenzhen Xu, Xu Wang, Hongjuan Yang, Lemin Zheng, Hongbing Fu
Development of luminescence probes with polarized and narrow emissions simultaneously is helpful for removing multiply scattered light and enables multiplexing detection, but it remains challenging to use conventional organic dyes, fluorescence proteins, and quantum dots. Here, we demonstrated smart one-dimensional microlaser probes (MLPs) by coating a thin layer of silica shell on the surface of organic nanowires (ONWs) of 1,4-dimethoxy-2,5-di[4'-(methylthio)styryl]benzene (TDSB), namely, ONW@SiO2 core-shell structures...
February 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28183595/carbon-nanotube-as-a-carrier-in-drug-delivery-system-for-carnosine-dipeptide-a-computer-simulation-study
#15
Sepideh Ketabi, Leila Rahmani
Biological application of carbon nanotube in drug delivery is our main concern in this investigation. For this purpose interaction of carnosine and carbon nanotube was studied in both gas phase and separately in aqueous media. Three possible interactions of carnosine dipeptide with (5,5) carbon nanotube in physiological media were considered. At first step each species were modeled using quantum mechanical calculations, in the next step, their properties in aqueous solution were studied by applying Monte Carlo simulations...
April 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28182433/vertical-substrate-mpcvd-epitaxial-nano-diamond-growth
#16
Yan-Kai Tzeng, Jingyuan Linda Zhang, Haiyu Lu, Hitoshi Ishiwata, Jeremy Dahl, Robert M K Carlson, Hao Yan, Peter R Schreiner, Jelena Vuckovic, Zhi-Xun Shen, Nicholas A Melosh, Steven Chu
Color center-containing nanodiamonds have many applications in quantum technologies and biology. Diamondoids, molecular-sized diamonds have been used as seeds in Chemical Vapor Deposition (CVD) growth. However, optimizing growth conditions to produce high crystal quality nanodiamonds with color centers requires varying growth conditions that often leads to ad-hoc and time-consuming, one-at-a-time testing of reaction conditions. In order to rapidly explore parameter space, we developed a microwave plasma CVD technique using a vertical, rather than horizontally oriented stage-substrate geometry...
February 9, 2017: Nano Letters
https://www.readbyqxmd.com/read/28181387/assessment-of-the-short-term-toxicity-of-tio2-nanofiber-in-sprague-dawley-rats
#17
Worlanyo E Gato, Daniel A Hunter, Ian C Byrd, Christopher A Mays, Wilson Yau, Ji Wu
Synthetic nanomaterials have many unique chemical and physical properties, mainly due to their high specific surface area and quantum confinement effect. Specifically, titanium dioxide (TiO2 ) nanomaterial has high stability, anticorrosive, and photocatalytic properties. However, there are concerns over adverse biological effects resulting from bioeffects. This study was to investigate adverse effects associated with acute ingestion of TiO2 nanofiber (TDNF). TDNF was fabricated via electrospinning method, followed by dissolution in water...
February 9, 2017: Environmental Toxicology
https://www.readbyqxmd.com/read/28178781/effects-of-surface-charges-on-the-bactericide-activity-of-cdte-zns-quantum-dots-a-cell-membrane-disruption-perspective
#18
Lu Lai, Sheng-Jin Li, Jing Feng, Ping Mei, Zhao-Hua Ren, Yan-Ling Chang, Yi Liu
The inhibitory effects of CdTe/ZnS quantum dots (QDs) modified with 3-mercaptopropionic acid (negatively charged) or cysteamine (positively charged) on the metabolic activity of Escherichia coli were investigated using biological microcalorimetry. Results show that the inhibitory ratio of positive QDs is higher than that of negative QDs. Transmission electron microscopy images indicate that QDs are prone to be adsorbed on the surface of E. coli. This condition disturbs the membrane structure and function of E...
February 20, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28176631/grid-based-continual-analysis-of-molecular-interior-for-drug-discovery-qsar-and-qspr
#19
A V Potemkin, M A Grishina, V A Potemkin
BACKGROUND: In 1979, R.D.Cramer and M.Milne made a first realization of the above mentioned principles attempting to compare molecules by aligning them in space and by mapping their molecular fields to a 3D grid. Further, this approach was developed as the DYLOMMS (DYnamic Lattice-Oriented Molecular Modelling System) approach. In 1984, H.Wold and S.Wold proposed the use of partial least squares (PLS) analysis, instead of principal component analysis, to correlate the field values with biological activities...
February 7, 2017: Current Drug Discovery Technologies
https://www.readbyqxmd.com/read/28169280/nanoscale-%C3%AF-%C3%AF-stacked-molecules-are-bound-by-collective-charge-fluctuations
#20
Jan Hermann, Dario Alfè, Alexandre Tkatchenko
Non-covalent π-π interactions are central to chemical and biological processes, yet the full understanding of their origin that would unite the simplicity of empirical approaches with the accuracy of quantum calculations is still missing. Here we employ a quantum-mechanical Hamiltonian model for van der Waals interactions, to demonstrate that intermolecular electron correlation in large supramolecular complexes at equilibrium distances is appropriately described by collective charge fluctuations. We visualize these fluctuations and provide connections both to orbital-based approaches to electron correlation, as well as to the simple London pairwise picture...
February 7, 2017: Nature Communications
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