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https://www.readbyqxmd.com/read/28544173/frozen-acrylamide-gels-as-dynamic-nuclear-polarization-matrices
#1
Jasmine Viger-Gravel, Pierrick Berruyer, David Gajan, Jean-Marie Basset, Anne Lesage, Paul Tordo, Olivier Ouari, Lyndon Emsley
We show that aqueous acrylamide gels can be used to provide dynamic nuclear polarization (DNP) NMR signal enhancements of around 200 at 9.4 T and 100 K. The enhancements are shown to increase with cross linker concentration and low concentrations of the AMUPol biradical. We show that this DNP matrix can be used in situations where conventional incipient wetness methods fail, such as to obtain DNP surface enhanced NMR spectra from inorganic nanoparticles. In particular, we obtain 113Cd spectra from CdTe-COOH NPs in minutes...
May 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544115/unprecedented-carbon-signal-enhancement-in-liquid-state-nmr-spectroscopy
#2
György Pintér, Harald Schwalbe
We shall overcome: As a result of efforts to overcome the sensitivity challenge of liquid-state NMR spectroscopy, a thousand-fold signal enhancement was achieved by dynamic nuclear polarization (DNP) for (13) C signals at high magnetic field (3.4 T) and room temperature, thereby exceeding the predicted limitations of high-field liquid-state in situ DNP.
May 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28538461/dnp-preparation-in-supporting-critical-skills-for-magnet%C3%A2-program-directors
#3
Sarah Lackey
Magnet® organizations are required to identify a Magnet program director (MPD), who plays a critical role in attaining and maintaining Magnet designation. The evidence is sparse related to qualifications or recommended educational levels of those assuming an MPD role. In this article, the author discusses how one of the DNP Essentials, clinical scholarship and the use of analytical methods for evidence-based practice, is reported to prepare nurses for the MPD role.
June 2017: Journal of Nursing Administration
https://www.readbyqxmd.com/read/28532680/decreased-spinal-endomorphin-2-contributes-to-mechanical-allodynia-in-streptozotocin-induced-diabetic-rats
#4
Le Niu, Guang-Hai Dai, Gao-Le He, Ming Yang, Hui-Min Hu, Zhong-Kai Liu, Nian-Song Qian, Yong-Liang Chen
Diabetic neuropathic pain (DNP) plays a major role in decreased life quality of diabetes patients, however, the neural mechanisms underlying DNP remain unclear. Endomorphins are the endogenous ligands for mu-opioid receptor. There is increasing evidence implicating the involvement of spinal endomorphin-2 (EM2) in neuropathic pain. In this study, using a streptozotocin induced diabetic rat model that displayed obvious mechanical allodynia, it was found that the expression of spinal EM2 was significantly decreased in DNP rats...
May 19, 2017: Neurochemistry International
https://www.readbyqxmd.com/read/28528745/measurement-of-electrochemical-conductance-of-penile-skin-using-sudoscan-%C3%A2-a-new-tool-to-assess-neurogenic-impotence
#5
Jean-Pascal Lefaucheur
OBJECTIVES: To investigate the value of electrochemical skin conductance (ESC) measurement at penile level using Sudoscan(®) for the diagnosis of neurogenic impotence in diabetics. METHODS: The following neurophysiological parameters were assessed in 25 male diabetics who complained of impotence and 25 age-matched normal male subjects without erectile dysfunction (age range: 29-70 years): ESC, sympathetic skin responses (SSR), warm detection thresholds (WDT), and cold detection thresholds (CDT) for the penis and the feet, vibration detection thresholds (VDT) for the penis, and sensory nerve conduction study of the dorsal nerve of the penis (DNP) with sensory nerve action potential (SNAP) recording...
May 18, 2017: Neurophysiologie Clinique, Clinical Neurophysiology
https://www.readbyqxmd.com/read/28517362/the-absence-of-quadrupolar-nuclei-facilitates-efficient-13-c-hyperpolarization-via-reversible-exchange-with-parahydrogen
#6
Danila A Barskiy, Roman V Shchepin, Christian P N Tanner, Johannes F P Colell, Boyd M Goodson, Thomas Theis, Warren S Warren, Eduard Y Chekmenev
Nuclear spin hyperpolarization techniques are revolutionizing the field of (13) C molecular MRI. While dissolution dynamic nuclear polarization (d-DNP) is currently the leading technique, it is generally slow (requiring ≈1 h) and costly (≈$USD10(6) ). As a consequence of carbon's central place in biochemistry, tremendous progress using (13) C d-DNP bioimaging has been demonstrated to date including a number of clinical trials. Despite numerous attempts to develop alternatives to d-DNP, the competing methods have faced significant translational challenges...
May 18, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28509544/search-for-electron-delocalization-from-fe-cn-6-3-to-the-dication-of-viologen-in-dnp-3-fe-cn-6-2%C3%A2-10h2o
#7
Ahmed S Abouelwafa, Andreas Hauser, Valeriu Mereacre, Yanhua Lan, Gary J Long, Fernande Grandjean, Gernot Buth, Christopher E Anson, Annie K Powell
K3Fe(CN)6 reacts with the viologen 1,1'-bis(2,4-dinitrophenyl)-4,4'-bipyridinium dication, (DNP)(2+), to form a supramolecular complex, (DNP)3[Fe(CN)6]2·10H2O (1). The crystal structure of 1 reveals that there are two [Fe(CN)6](3-) anions within an organic framework of three (DNP)(2+) cations with the shortest Fe(III)···Fe(III) distances of ca. 9.8 Å, distances that minimize extensive long-range magnetic exchange coupling interactions between the [Fe(CN)6](3-) anions, and, thus, 1 is paramagnetic above ca...
May 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28508552/real-time-analysis-of-folding-upon-binding-of-a-disordered-protein-by-using-dissolution-dnp%C3%A2-nmr-spectroscopy
#8
Mukundan Ragavan, Luigi I Iconaru, Cheon-Gil Park, Richard W Kriwacki, Christian Hilty
The kinase inhibitory domain of the cell cycle regulatory protein p27(Kip1) (p27) was nuclear spin hyperpolarized using dissolution dynamic nuclear polarization (D-DNP). While intrinsically disordered in isolation, p27 adopts secondary structural motifs, including an α-helical structure, upon binding to cyclin-dependent kinase 2 (Cdk2)/cyclin A. The sensitivity gains obtained with hyperpolarization enable the real-time observation of (13) C NMR signals during p27 folding upon binding to Cdk2/cyclin A on a time scale of several seconds...
May 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28507688/donor-acceptor-stacking-arrangements-in-bulk-and-thin-film-high-mobility-conjugated-polymers-characterized-using-molecular-modelling-and-mas-and-surface-enhanced-solid-state-nmr-spectroscopy
#9
Sachin R Chaudhari, John M Griffin, Katharina Broch, Anne Lesage, Vincent Lemaur, Dmytro Dudenko, Yoann Olivier, Henning Sirringhaus, Lyndon Emsley, Clare P Grey
Conjugated polymers show promising properties as cheap, sustainable and solution-processable semiconductors. A key challenge in the development of these materials is to determine the polymer chain structure, conformation and packing in both the bulk polymer and in thin films typically used in devices. However, many characterisation techniques are unable to provide atomic-level structural information owing to the presence of disorder. Here, we use molecular modelling, magic-angle spinning (MAS) and dynamic nuclear polarisation surface-enhanced NMR spectroscopy (DNP SENS) to characterise the polymer backbone group conformations and packing arrangement in the high-mobility donor-acceptor copolymer diketopyrrolo-pyrrole-dithienylthieno[3,2-b]thiophene (DPP-DTT)...
April 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28500593/assessment-of-protein-carbonylation-and-protein-tyrosine-phosphatase-ptp-oxidation-in-vascular-smooth-muscle-cells-vsmcs-using-immunoblotting-approaches
#10
Sofia Tsiropoulou, Rhian M Touyz
Post-translational modification of proteins, such as phosphorylation and oxidation, plays a major role in cellular signaling by influencing protein structure and function. In vascular cells, in addition to influencing phosphorylation, angiotensin II (Ang II) induces oxidation of proteins, important in redox signaling in the cardiovascular and renal systems. The present chapter describes immunoblotting approaches to assess irreversible protein carbonylation and protein tyrosine phosphatase (PTPs) oxidation status in the proteome of vascular smooth muscle cells (VSMC)...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28499071/natural-abundance-17o-dnp-nmr-provides-precise-o-h-distances-and-insights-into-the-br%C3%A3-nsted-acidity-of-heterogeneous-catalysts
#11
Frédéric A Perras, Zhuoran Wang, Pranjali Naik, Igor I Slowing, Marek Pruski
Heterogeneous Brønsted acid catalysts are tremendously important in industry, particularly in catalytic cracking processes. Here we show that these Brønsted acid sites can be directly observed at natural abundance by 17O DNP surface-enhanced NMR spectroscopy (SENS). We additionally show that the O-H bond length in these catalysts can be measured with a sub-pm precision, to enable a direct structural gauge of the lability of protons in a given material, which is correlated with the material's pH of zero point of charge...
May 12, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28497528/frequency-swept-integrated-solid-effect
#12
Thach V Can, Ralph T Weber, Joseph J Walish, Timothy M Swager, Robert G Griffin
The efficiency of continuous wave dynamic nuclear polarization (DNP) experiments decreases at the high magnetic fields used in contemporary high-resolution NMR applications. To recover the expected signal enhancements from DNP, we explored time domain experiments such as NOVEL which matches the electron Rabi frequency to the nuclear Larmor frequency to mediate polarization transfer. However, satisfying this matching condition at high frequencies is technically demanding. As an alternative we report here frequency-swept integrated solid effect (FS-ISE) experiments that allow low power sweeps of the exciting microwave frequencies to constructively integrate the negative and positive polarizations of the solid effect, thereby producing a polarization efficiency comparable to (±10 % difference) NOVEL...
May 12, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28488014/effect-of-nitrooxy-compounds-with-different-molecular-structures-on-the-rumen-methanogenesis-metabolic-profile-and-methanogenic-community
#13
Wei Jin, Zhenxiang Meng, Jing Wang, Yanfen Cheng, Weiyun Zhu
Rumen in vitro fermentation was used to evaluate the capacity of nitrooxy compounds to mitigate rumen methane production. The following three nitrooxy compounds, each with different molecular structures, were evaluated: 2,2-dimethyl-3-(nitrooxy) propanoic (DNP), N-[2-(Nitrooxy)ethyl]-3-pyridinecarboxamide (NPD), and nitroglycerin (NG). All three compounds substantially decreased the total gas production, methane production, and the acetate:propionate ratio, while increasing hydrogen production. The growth of methanogens was specifically inhibited by all three compounds, without affecting the abundance of bacteria, anaerobic fungi, or protozoa...
May 10, 2017: Current Microbiology
https://www.readbyqxmd.com/read/28487815/phospholipid-arrays-on-porous-polymer-coatings-generated-by-micro-contact-spotting
#14
Sylwia Sekula-Neuner, Monica de Freitas, Lea-Marie Tröster, Tobias Jochum, Pavel A Levkin, Michael Hirtz, Harald Fuchs
Nanoporous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) (HEMA-EDMA) is used as a 3D mesh for spotting lipid arrays. Its porous structure is an ideal matrix for lipid ink to infiltrate, resulting in higher fluorescent signal intensity as compared to similar arrays on strictly 2D substrates like glass. The embedded lipid arrays show high stability against washing steps, while still being accessible for protein and antibody binding. To characterize binding to polymer-embedded lipids we have applied Streptavidin as well as biologically important biotinylated androgen receptor binding onto 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(cap biotinyl) (Biotinyl Cap PE) and anti-DNP IgE recognition of 2,4-dinitrophenyl[1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[6-[(2,4-dinitrophenyl)amino]hexanoyl] (DNP)] antigen...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/28482216/arbitrary-waveform-modulated-pulse-epr-at-200ghz
#15
Ilia Kaminker, Ryan Barnes, Songi Han
We report here on the implementation of arbitrary waveform generation (AWG) capabilities at ∼200GHz into an Electron Paramagnetic Resonance (EPR) and Dynamic Nuclear Polarization (DNP) instrument platform operating at 7T. This is achieved with the integration of a 1GHz, 2 channel, digital to analog converter (DAC) board that enables the generation of coherent arbitrary waveforms at Ku-band frequencies with 1ns resolution into an existing architecture of a solid state amplifier multiplier chain (AMC). This allows for the generation of arbitrary phase- and amplitude-modulated waveforms at 200GHz with >150mW power...
April 27, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28461894/polarized-proton-spin-density-images-the-tyrosyl-radical-locations-in-bovine-liver-catalase
#16
Oliver Zimmer, Hélène M Jouve, Heinrich B Stuhrmann
A tyrosyl radical, as part of the amino acid chain of bovine liver catalase, supports dynamic proton spin polarization (DNP). Finding the position of the tyrosyl radical within the macromolecule relies on the accumulation of proton polarization close to it, which is readily observed by polarized neutron scattering. The nuclear scattering amplitude due to the polarization of protons less than 10 Å distant from the tyrosyl radical is ten times larger than the amplitude of magnetic neutron scattering from an unpaired polarized electron of the same radical...
September 1, 2016: IUCrJ
https://www.readbyqxmd.com/read/28461483/efficient-assignment-and-nmr-analysis-of-an-intact-virus-using-sequential-side-chain-correlations-and-dnp-sensitization
#17
Ivan V Sergeyev, Boris Itin, Rivkah Rogawski, Loren A Day, Ann E McDermott
An experimental strategy has been developed to increase the efficiency of dynamic nuclear polarization (DNP) in solid-state NMR studies. The method makes assignments simpler, faster, and more reliable via sequential correlations of both side-chain and Cα resonances. The approach is particularly suited to complex biomolecules and systems with significant chemical-shift degeneracy. It was designed to overcome the spectral congestion and line broadening that occur due to sample freezing at the cryogenic temperatures required for DNP...
May 1, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28454272/dinitrophenyl-hapten-with-laser-immunotherapy-for-advanced-malignant-melanoma-a-clinical-study
#18
Dian-Jun Chen, Xiao-Song Li, Hui Zhao, Yan Fu, Huan-Rong Kang, Fang-Fang Yao, Jia Hu, Nan Qi, Huan-Huan Zhang, Nan Du, Wei-R Chen
The present study aimed to evaluate the efficacy and safety of in situ immunotherapy with dinitrophenyl (DNP) hapten in combination with laser therapy for patients with malignant melanoma (MM). Between February 2008 and March 2012, 72 patients with stage III or IV MM were enrolled. Patients received in situ DNP alone (n=32) or in combination with laser therapy (n=32), and each group received dacarbazine chemotherapy. The levels of peripheral cluster of differentiation (CD)4(+)CD25(+) regulatory T cells (Tregs), interleukin (IL)-10 and tumor growth factor (TGF)-β were detected by ELISA...
March 2017: Oncology Letters
https://www.readbyqxmd.com/read/28451235/welcoming-natural-isotopic-abundance-in-solid-state-nmr-probing-%C3%AF-stacking-and-supramolecular-structure-of-organic-nanoassemblies-using-dnp
#19
Katharina Märker, Subhradip Paul, Carlos Fernández-de-Alba, Daniel Lee, Jean-Marie Mouesca, Sabine Hediger, Gaël De Paëpe
The self-assembly of small organic molecules is an intriguing phenomenon, which provides nanoscale structures for applications in numerous fields from medicine to molecular electronics. Detailed knowledge of their structure, in particular on the supramolecular level, is a prerequisite for the rational design of improved self-assembled systems. In this work, we prove the feasibility of a novel concept of NMR-based 3D structure determination of such assemblies in the solid state. The key point of this concept is the deliberate use of samples that contain (13)C at its natural isotopic abundance (NA, 1...
February 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28451187/dendritic-polarizing-agents-for-dnp-sens
#20
Wei-Chih Liao, Ta-Chung Ong, David Gajan, Florian Bernada, Claire Sauvée, Maxim Yulikov, Margherita Pucino, Roman Schowner, Martin Schwarzwälder, Michael R Buchmeiser, Gunnar Jeschke, Paul Tordo, Olivier Ouari, Anne Lesage, Lyndon Emsley, Christophe Copéret
Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an effective method to significantly improve solid-state NMR investigation of solid surfaces. The presence of unpaired electrons (polarizing agents) is crucial for DNP, but it has drawbacks such as leading to faster nuclear spin relaxation, or even reaction with the substrate under investigation. The latter can be a particular problem for heterogeneous catalysts. Here, we present a series of carbosilane-based dendritic polarizing agents, in which the bulky dendrimer can reduce the interaction between the solid surface and the free radical...
January 1, 2017: Chemical Science
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