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Or Szekely, Gregory Lars Olsen, Isabella Caterina Felli, Lucio Frydman
This study demonstrates the usefulness derived from relying on hyperpolarized water obtained by dissolution DNP, for site-resolved biophysical NMR studies of intrinsically disordered proteins. Thanks to the facile amide-solvent exchange experienced by protons in these proteins, 2D NMR experiments that like HMQC rely on the polarization of the amide protons, can be enhanced using hyperpolarized water by several orders of magnitude over their conventional counterparts. Optimizations of the DNP procedure and of the subsequent injection into the protein sample are necessary to achieve these gains while preserving state-of-the-art resolution; procedures enabling this transfer of the hyperpolarized water and the achievement of foamless hyperpolarized protein solutions, are here demonstrated...
March 12, 2018: Analytical Chemistry
Khaled G Abdel-Wahhab, Eitedal M Daoud, Aliaa El Gendy, Hagar H Mourad, Fathia A Mannaa, Maha M Saber
Diabetic neuropathy (DN) is the highly occurred complication of diabetes mellitus; it has been defined as an event of peripheral nerve dysfunction characterized by pain, allodynia, hyperalgesia, and paraesthesia. The current study was conducted to evaluate the efficacy of low-level laser therapy (LLLT) in the management of neuropathy in diabetic rats. The used animals were divided into the following groups: negative control, streptozotocin-induced diabetic rats, and diabetic rats with peripheral neuropathy (DNP) and DNP treated with gabapentin or with LLLT...
March 12, 2018: Applied Biochemistry and Biotechnology
Miku Maruyama, Miki Kobayashi, Takeshi Uchida, Eisaku Shimizu, Hironori Higashio, Misa Ohno, Shota Uesugi, Ken-Ichi Kimura
Amber is fossilized tree resin and several biologically active compounds were isolated from ambers using the growth-restoring activity of the mutant yeast [Saccharomyces cerevisiae (zds1∆ erg3∆ pdr1∆ pdr3∆)] involving Ca2+ -signal transduction. The aim of this study is to investigate the anti-allergic effect of both the methanol extract of Kuji amber (MEKA) and its main biologically active constituent, kujigamberol (15,20-dinor-5,7,9-labdatrien-18-ol) having activity against the mutant yeast. Both MEKA and kujigamberol inhibited the degranulation of RBL-2H3 cells by stimulation of thapsigargin (Tg) (IC50  = 15...
March 5, 2018: Fitoterapia
Kent R Thurber, Thanh-Ngoc Le, Victor Changcoco, David J R Brook
Solid-state dynamic nuclear polarization (DNP) using the cross-effect relies on radical pairs whose electron spin resonance (ESR) frequencies differ by the nuclear magnetic resonance (NMR) frequency. We measure the DNP provided by a new water-soluble verdazyl radical, verdazyl-ribose, under both magic-angle spinning (MAS) and static sample conditions at 9.4 T, and compare it to a nitroxide radical, 4-hydroxy-TEMPO. We find that verdazyl-ribose is an effective radical for cross-effect DNP, with the best relative results for a non-spinning sample...
March 1, 2018: Journal of Magnetic Resonance
Sten O Nilsson Lill, Cory M Widdifield, Anna Pettersen, Anna Svensk Ankarberg, Maria Lindkvist, Peter Aldred, Sandra Gracin, Norman Shankland, Kenneth Shankland, Staffan Schantz, Lyndon Emsley
By the combined use of powder and single crystal X-ray diffraction, solid-state NMR, and molecular modelling, the crystal structures of two systems containing the unusually large tenapanor drug molecule have been determined: the free form, ANHY and a dihydrochloride salt form, 2HCl. Dynamic nuclear polarization (DNP) assisted solid-state NMR (SSNMR) crystallography investigations were found essential for the final assignment, and were used to validate the crystal structure of ANHY. From the structural informatics analysis of ANHY and 2HCl, conformational ring differences in one part of the molecule were observed which influences the relative orientation of a methyl group on a ring nitrogen and thereby impacts the crystallizability of the dihydrochloride salt...
February 28, 2018: Molecular Pharmaceutics
Qing Zhe Ni, Thach Van Can, Eugenio Daviso, Marina Belenky, Robert G Griffin, Judith Herzfeld
Despite much attention, the path of the highly consequential primary proton transfer in the light-driven ion pump bacteriorhodopsin (bR) remains mysterious. Here we use DNP-enhanced magic angle spinning (MAS) NMR to study critical elements of the active site just before the Schiff base (SB) deprotonates (in the L intermediate), immediately after the SB has deprotonated and Asp85 has become protonated (in the Mo intermediate), and just after the SB has reprotonated and Asp96 has deprotonated (in the N intermediate)...
February 28, 2018: Journal of the American Chemical Society
Ruth M Labardee
This column shares the best evidence-based strategies and innovative ideas on how to facilitate the learning and implementation of EBP principles and processes by clinicians as well as nursing and interprofessional students. Guidelines for submission are available at
February 27, 2018: Worldviews on Evidence-based Nursing
Jeffrey Camacho-Bunquin, Magali S Ferrandon, Hyuntae Sohn, Dali Yang, Cong Liu, Patricia Ignacio-de Leon, Frédéric A Perras, Marek Pruski, Peter C Stair, Massimiliano Delferro
Well-defined organoplatinum(IV) sites were grafted on a Zn(II)-modified SiO2 support via surface organometallic chemistry in toluene at room temperature. Solid-state spectroscopies including XAS, DRIFTS, DRUV-Vis, and solid-state (SS)NMR enhanced by dynamic nuclear polarization (DNP), as well as TPR-H2 and TEM techniques revealed highly dispersed (methylcyclopentadienyl)methylplatinum(IV) sites on the surface ((MeCp)PtMe/Zn/SiO2, 1). In addition, computational modelling suggests that the surface reaction of (MeCp)PtMe3 with Zn(II)-modified SiO2 support is thermodynamically favorable (∆G = -12...
February 27, 2018: Journal of the American Chemical Society
Gigin Lin, Chyong-Huey Lai, Tzu-Chen Yen
Molecular imaging (mainly PET and MR imaging) has played important roles in gynecologic oncology. Emerging MR-based technologies, including DWI, CEST, DCE-MR imaging, MRS, and DNP, as well as FDG-PET and many novel PET radiotracers, will continuously improve practices. In combination with radiomics analysis, a new era of decision making in personalized medicine and precisely guided radiation treatment planning or real-time surgical interventions is being entered into, which will directly impact on patient survival...
April 2018: PET Clinics
Bertrand Plainchont, Pierrick Berruyer, Jean-Nicolas Dumez, Sami Jannin, Patrick Giraudeau
Dynamic nuclear polarization (DNP) can boost sensitivity in nuclear magnetic resonance (NMR) experiments by several orders of magnitude. This review illustrates how the coupling of DNP with both liquid- and solid-state NMR spectroscopy has the potential to considerably extend the range of applications of NMR in analytical chemistry.
February 26, 2018: Analytical Chemistry
Jiayue Yan, Juli Broggi, Josué Martínez-de la Puente, Rafael Gutiérrez-López, Laura Gangoso, Ramón Soriguer, Jordi Figuerola
BACKGROUND: Host selection by mosquitoes plays a central role in the transmission of vector-borne infectious diseases. Although interspecific variation in mosquito attraction has often been reported, the mechanisms underlying intraspecific differences in hosts' attractiveness to mosquitoes are still poorly known. Metabolic rate is related to several physiological parameters used as location cues by mosquitoes, and so potentially affect host-vector contact rates. Therefore, individual hosts with higher metabolic rates should be more attractive to host-seeking mosquitoes...
February 23, 2018: Parasites & Vectors
Faith J Scott, Edward P Saliba, Brice J Albert, Nicholas Alaniva, Erika L Sesti, Chukun Gao, Natalie C Golota, Eric J Choi, Anil P Jagtap, Johannes J Wittmann, Michael Eckardt, Wolfgang Harneit, Björn Corzilius, Snorri Th Sigurdsson, Alexander B Barnes
We describe a frequency-agile gyrotron which can generate frequency-chirped microwave pulses. An arbitrary waveform generator (AWG) within the NMR spectrometer controls the microwave frequency, enabling synchronized pulsed control of both electron and nuclear spins. We demonstrate that the acceleration of emitted electrons, and thus the microwave frequency, can be quickly changed by varying the anode voltage. This strategy results in much faster frequency response than can be achieved by changing the potential of the electron emitter, and does not require a custom triode electron gun...
February 12, 2018: Journal of Magnetic Resonance
Chia-Hsiu Chen, Yunyi Wang, Christian Hilty
The nuclear Overhauser effect (NOE) is a primary means to characterize intermolecular interactions using modern NMR spectroscopy. Multiple experiments measured using different mixing time can be used for quantifying NOE buildup and measuring cross-relaxation rates. However, this approach using conventional multi-dimensional NMR is time consuming. Hyperpolarization by dissolution dynamic nuclear polarization (D-DNP) can generate deviations from equilibrium spin polarization by orders of magnitude, thereby enhancing signals and allowing to characterize NOE build up in real-time...
February 19, 2018: Methods: a Companion to Methods in Enzymology
Pelayo Fernandez-Acebal, Oded Rosolio, Jochen Scheuer, Christoph Müller, Samuel Müller, Simon Schmitt, Liam P McGuinness, Ilai Schwartz, Qiong Chen, Alex Retzker, Boris Naydenov, Fedor Jelezko, Martin B Plenio
Efficient polarization of organic molecules is of extraordinary relevance when performing nuclear magnetic resonance (NMR) and imaging. Commercially available routes to dynamical nuclear polarization (DNP) work at extremely low-temperatures, relying on the solidification of organic samples and thus bringing the molecules out of their ambient thermal conditions. In this work we investigate polarization transfer from optically-pumped nitrogen vacancy centers in diamond to external molecules at room temperature...
February 22, 2018: Nano Letters
Sebastien Alphonse, Boris Itin, Reza Khayat, Ranajeet Ghose
While solid-state NMR (ssNMR) has emerged as a powerful technique to study viral capsids, current studies are limited to capsids formed from single proteins or single polyproteins. The ability to selectively label individual protein components within multi-protein viral capsids and the resulting spectral simplification will facilitate the extension of ssNMR techniques to complex viruses. In vitro capsid assembly by combining individually purified, labeled and unlabeled components in NMR quantities is not a viable option for most viruses...
February 21, 2018: Biochemistry
Sraa Abu-Melha
A new series of 2-amino-5-arylazothiazole derivatives has been designed and synthesized in 61-78% yields and screened as potential antibacterial drug candidates against the Gram negative bacterium Escherichia coli. The geometry of the title compounds were being studied using the Material Studio package and semi-core pseudopods calculations (dspp) were performed with the double numerica basis sets plus polarization functional (DNP) to predict the properties of materials using the hybrid FT/B3LYP method. Modeling calculations, especially the (EH -EL ) difference and the energetic parameters revealed that some of the title compounds may be promising tools for further research work and the activity is structure dependent...
February 15, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Christian Hundshammer, Stephan Düwel, David Ruseckas, Geoffrey Topping, Piotr Dzien, Christoph Müller, Benedikt Feuerecker, Jan B Hövener, Axel Haase, Markus Schwaiger, Steffen J Glaser, Franz Schilling
pH is a tightly regulated physiological parameter that is often altered in diseased states like cancer. The development of biosensors that can be used to non-invasively image pH with hyperpolarized (HP) magnetic resonance spectroscopic imaging has therefore recently gained tremendous interest. However, most of the known HP-sensors have only individually and not comprehensively been analyzed for their biocompatibility, their pH sensitivity under physiological conditions, and the effects of chemical derivatization on their logarithmic acid dissociation constant (p K a )...
February 15, 2018: Sensors
Thierry Dubroca, Adam N Smith, Kevin J Pike, Stuart Froud, Richard Wylde, Bianca Trociewitz, Johannes McKay, Frederic Mentink-Vigier, Johan van Tol, Sungsool Wi, William Brey, Joanna R Long, Lucio Frydman, Stephen Hill
Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation...
January 31, 2018: Journal of Magnetic Resonance
Matthieu Cavaillès, Aurélien Bornet, Xavier Jaurand, Basile Vuichoud, David Baudouin, Mathieu Baudin, Laurent Veyre, Geoffrey Baudenhausen, Jean-Nicolas Dumez, Sami Jannin, Christophe Copéret, Chloé Thieuleux
Tailoring the physical features and the porous network architecture of silica-based hyperpolarizing solids containing TEMPO radicals, known as HYPSO (HYbrid Polarizing SOlids), enable unprecedented performance of dissolution Dynamic Nuclear Polarization (d-DNP). High polarization values up to P(1H) = 99 % were reached for samples impregnated with a mixture of H2O:D2O and loaded in a 6.7 T polarizer at temperatures around 1.2 K. These HYPSO materials combine the best performance of homogeneous DNP formulations with the advantages of solid polarizing matrices which provide hyperpolarized solutions free of any - potentially toxic - additives (radicals and glass-forming agents)...
February 19, 2018: Angewandte Chemie
Xiaoling Wang, Johannes E McKay, Bimala Lama, Johan van Tol, Tinghui Li, Kyle Kirkpatrick, Zhehong Gan, Stephen Hill, Joanna R Long, Harry C Dorn
We show increased dynamic nuclear polarization by adding a low dosage of a S = 15/2 Gd based endohedral metallofullerene (EMF) to DNP samples. By adding 60 μM Gd2 @C79 N, the nuclear polarization of1 H and13 C spins from 40 mM 4-oxo-TEMPO increases by approximately 40% and 50%, respectively, at 5 T and 1.2 K. Electron-electron double resonance (ELDOR) measurements show that the high spin EMF shortens the electron relaxation times and increases electron spectral diffusion leading to the increased DNP enhancement...
February 19, 2018: Chemical Communications: Chem Comm
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