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https://www.readbyqxmd.com/read/28437077/peptide-and-protein-dynamics-and-low-temperature-dnp-magic-angle-spinning-nmr
#1
Qing Zhe Ni, Evgeny Markhasin, Thach V Can, Björn Corzilius, Kong O Tan, Alexander B Barnes, Eugenio Daviso, Yongchao Su, Judith Herzfeld, Robert G Griffin
In DNP MAS NMR experiments at ~80-110 K, the structurally important -13CH3 and -15NH3+ signals in MAS spectra of biological samples disappear due to the interference of the molecular motions with the 1H decoupling. Here we investigate the effect of these dynamic processes on the NMR lineshapes and signal intensities in several typical systems: (1) microcrystalline APG, (2) membrane protein bR, (3) amyloid fibrils PI3-SH3, (4) monomeric alanine-CD3 and (5) the pro-tonated and deuterated dipeptide N-Ac-VL over 78-300 K...
April 24, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28433011/ramped-amplitude-novel
#2
T V Can, R T Weber, J J Walish, T M Swager, R G Griffin
We present a pulsed dynamic nuclear polarization (DNP) study using a ramped-amplitude nuclear orientation via electron spin locking (RA-NOVEL) sequence that utilizes a fast arbitrary waveform generator (AWG) to modulate the microwave pulses together with samples doped with narrow-line radicals such as 1,3-bisdiphenylene-2-phenylallyl (BDPA), sulfonated-BDPA (SA-BDPA), and trityl-OX063. Similar to ramped-amplitude cross polarization in solid-state nuclear magnetic resonance, RA-NOVEL improves the DNP efficiency by a factor of up to 1...
April 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28429936/electron-decoupling-with-dynamic-nuclear-polarization-in-rotating-solids
#3
Edward P Saliba, Erika L Sesti, Faith J Scott, Brice J Albert, Eric J Choi, Nicholas Alaniva, Chukun Gao, Alexander B Barnes
Dynamic nuclear polarization (DNP) can enhance NMR sensitivity by orders of magnitude by transferring spin polarization from electron paramagnetic resonance (EPR) to NMR. However, paramagnetic DNP polarizing agents can have deleterious effects on NMR signals. Electron spin decoupling can mitigate these paramagnetic relaxation effects. We demonstrate electron decoupling experiments in conjunction with DNP and magic angle spinning (MAS) NMR spectroscopy. Following a DNP and spin diffusion period, the microwave irradiation frequency is quickly tuned on-resonance with electrons on the DNP polarizing agent...
April 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28425462/role-of-chiral-quantum-hall-edge-states-in-nuclear-spin-polarization
#4
Kaifeng Yang, Katsumi Nagase, Yoshiro Hirayama, Tetsuya D Mishima, Michael B Santos, Hongwu Liu
Resistively detected NMR (RDNMR) based on dynamic nuclear polarization (DNP) in a quantum Hall ferromagnet (QHF) is a highly sensitive method for the discovery of fascinating quantum Hall phases; however, the mechanism of this DNP and, in particular, the role of quantum Hall edge states in it are unclear. Here we demonstrate the important but previously unrecognized effect of chiral edge modes on the nuclear spin polarization. A side-by-side comparison of the RDNMR signals from Hall bar and Corbino disk configurations allows us to distinguish the contributions of bulk and edge states to DNP in QHF...
April 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28423212/persistent-radicals-of-self-assembled-benzophenone-bis-urea-macrocycles-characterization-and-application-as-a-polarizing-agent-for-solid-state-dnp-mas-spectroscopy
#5
Baillie A DeHaven, John T Tokarski, Arthur A Korous, Frederic Mentink-Vigier, Thomas M Makris, Alexander M Brugh, Malcolm D E Forbes, Johan van Tol, Clifford Russ Bowers, Linda S Shimizu
UV-irradiation of a self-assembled benzophenone bis-urea macrocycle generates μM amounts of radicals that persist for weeks under ambient conditions. High-Field EPR and variable temperature X-band EPR studies suggest a resonance stabilized radical pair through H-abstraction. These endogenous radicals were applied as a polarizing agent for magic angle spinning (MAS) dynamic nuclear polarization (DNP) NMR enhancement. The field-stepped DNP enhancement profile exhibits a sharp peak with a maximum enhancement of εon/off = 4 superimposed on a nearly constant DNP enhancement of εon/off = 2 over a broad field range...
April 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28422500/influence-of-13-c-isotopic-labeling-location-on-dynamic-nuclear-polarization-of-acetate
#6
Peter Niedbalski, Christopher Parish, Andhika Kiswandhi, Zoltan Kovacs, Lloyd Lumata
Dynamic nuclear polarization (DNP) via the dissolution method has alleviated the insensitivity problem in liquid-state nuclear magnetic resonance (NMR) spectroscopy by amplifying the signals by several thousand-fold. This NMR signal amplification process emanates from the microwave-mediated transfer of high electron spin alignment to the nuclear spins at high magnetic field and cryogenic temperature. Since the interplay between the electrons and nuclei is crucial, the chemical composition of a DNP sample such as the type of free radical used, glassing solvents, or the nature of the target nuclei can significantly affect the NMR signal enhancement levels that can be attained with DNP...
April 24, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28407455/construction-and-13-c-hyperpolarization-efficiency-of-a-180%C3%A2-ghz-dissolution-dynamic-nuclear-polarization-system
#7
Andhika Kiswandhi, Peter Niedbalski, Christopher Parish, Sarah Ferguson, David Taylor, George McDonald, Lloyd Lumata
Dynamic nuclear polarization (DNP) via the dissolution method has become one of the rapidly emerging techniques to alleviate the low signal sensitivity in nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI). In this paper, we report on the development and (13) C hyperpolarization efficiency of a homebuilt dynamic nuclear polarization (DNP) system operating at 6.423 T and 1.4 K. The DNP hyperpolarizer system was assembled on a wide-bore superconducting magnet, equipped with a standard continuous-flow cryostat, and a 180 GHz microwave source with 120 mW power output and wide 4 GHz frequency tuning range...
April 13, 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28406297/binding-analysis-of-some-classical-acetylcholinesterase-inhibitors-insights-for-a-rational-design-using-free-energy-perturbation-method-calculations-with-qm-mm-md-simulations
#8
Érica C M Nascimento, Mónica Oliva, Katarzyna Świderek, João B L Martins, Juan Andrés
In the present study, the binding free energy of some classical inhibitors (DMT, DNP, GNT, HUP, THA) with acetylcholinesterase (AChE) is calculated by means of the free energy perturbation (FEP) method based on hybrid quantum mechanics and molecular mechanics (QM/MM) potentials. The results highlight the key role of the van der Waals interaction for the inhibition process, since the contribution of this term to the binding free energy is almost as decisive as the electrostatic one. The analysis of the geometrical parameters and the interaction energy per residue along the QM/MM molecular dynamics (MD) simulations highlights the most relevant interactions in the different AChE-ligand systems, showing that the charged residues with a more prominent contribution to the interaction energy are Asp72 and Glu199, although the relative importance depends on the molecular size of the ligand...
April 24, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28401372/choroidal-thickness-alterations-in-diabetic-nephropathy-patients-with-early-or-no-diabetic-retinopathy
#9
Can Kocasarac, Yavuz Yigit, Erkan Sengul, Yildirim Beyazit Sakalar
PURPOSE: To assess changes in choroidal thickness (CT) in diabetes patients with and without diabetic nephropathy using enhanced depth imaging spectral domain optical coherence tomography (EDI-OCT). METHODS: Thirty-five type 2 diabetes patients with a diagnosis of diabetic nephropathy (DNP) in nephrology department and 35 type 2 diabetes patients without nephropathy (non-DNP) were included in our prospective study consecutively. The control group comprised 34 healthy individuals...
April 11, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28394646/prenatal-diagnosis-of-a-case-of-norrie-disease-with-late-development-of-bilateral-ocular-malformation
#10
Li Hong Wu, Li-Hong Chen, Hongning Xie, Ying-Jun Xie
We report a case of Norrie disease, diagnosed by prenatal ultrasound, confirmed by Sanger sequencing of the DNP gene from the aborted fetal cord blood and histologically. Prenatal ultrasound revealed no abnormality in either eye at 22(+1) and 31(+4) gestational weeks, but at 36(+5) gestational weeks both eyes had massive vitreous cavity opacities with complete retinal detachment. Norrie disease was initially suspected because of an older male sibling with the disease. To our knowledge, prenatal ultrasound diagnosis of Norrie disease has been previously described only one case in 1993 in a 34-week-old fetus...
April 10, 2017: Fetal and Pediatric Pathology
https://www.readbyqxmd.com/read/28394301/structural-analysis-and-immuno-stimulating-activity-of-an-acidic-polysaccharide-from-the-stems-of-dendrobium-nobile-lindl
#11
Jun-Hui Wang, Shu-Rong Zuo, Jian-Ping Luo
Dendrobium nobile Lindl., an epiphytic herb distributed in the Southeast Asia, is used as a tonic and antipyretic herbal medicine in China. In this study, a water-soluble acidic heteropolysaccharide, DNP-W4, containing mannose, glucose, galactose, xylose, rhamnose, and galacturonic acid, in the molar ratios of 1.0:4.9:2.5:0.5:1.0:0.9, was obtained from the stems of Dendrobium nobile Lindl. Using methylation analysis, partial acid hydrolysis, pectolyase treatment, NMR, and ESI-MS, the structure of DNP-W4 was elucidated...
April 10, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28394124/chiral-recognition-by-dissolution-dnp-nmr-spectroscopy-of-13-c-labeled-dl-methionine
#12
Eva Monteagudo, Albert Virgili, Teodor Parella, Míriam Pérez-Trujillo
A method based on d-DNP NMR spectroscopy to study chiral recognition is described for the first time. The enantiodifferentiation of a racemic metabolite in a millimolar aqueous solution using a chiral solvating agent was performed. Hyperpolarized (13)C-labeled dl-methionine enantiomers were differently observed with a single-scan (13)C NMR experiment, while the chiral auxiliary at thermal equilibrium remained unobserved. The method developed entails a step forward in the chiral recognition of small molecules by NMR spectroscopy, opening new possibilities in situations where the sensitivity is limited, for example, when a low concentration of analyte is available or when the measurement of an insensitive nucleus, like (13)C, is required...
April 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28388829/evidence-based-practice-beliefs-and-implementation-in-doctor-of-nursing-practice-students
#13
Joanne K Singleton
BACKGROUND: Doctors of Nursing Practice focus on leadership in evidence-based practice (EBP). EBP is influenced by one's beliefs in and implementation of EBP. Little is known to date about the EBP beliefs and implementation of Doctor of Nursing Practice students and outcomes of Doctor of Nursing Practice education. AIMS: Guided by the Advancing Research and Clinical practice through close Collaboration (ARCC) Model, the Evidence-Based Practice Beliefs (EBPB) and Implementation (EBPI) tools were used to assess the impact of EBP as a program pillar, curricular thread, and content area on EBPB and EBPI of Doctor of Nursing Practice-Family Nurse Practitioner students...
April 7, 2017: Worldviews on Evidence-based Nursing
https://www.readbyqxmd.com/read/28383886/modified-atomic-orbital-overlap-molecular-level-proof-of-the-nucleophilic-cleavage-propensity-of-dinitrophenol-based-probes
#14
Mangili Venkateswarulu, Sunil Kumar, Subrata Ghosh
Out of six possible positional isomers of dinitrophenol, only 2,4-DNP has been used extensively by many researchers for developing reactive molecular probes. But the question remains unanswered: why has 2,4-isomer only emerged as labile protecting group? To answer this question, six molecular probes using available DNP isomers were developed and investigated to evaluate the effect of extent of atomic orbital overlap on their reactivity. We have proved for the first time at the molecular level that the o-NO2 group contributes less as compared to p-NO2 group toward the reactivity of 2,4-DNP based probes...
April 6, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28365491/solvent-signal-suppression-for-high-resolution-mas-dnp
#15
Daniel Lee, Sachin R Chaudhari, Gaël De Paëpe
Dynamic nuclear polarization (DNP) has become a powerful tool to substantially increase the sensitivity of high-field magic angle spinning (MAS) solid-state NMR experiments. The addition of dissolved hyperpolarizing agents usually results in the presence of solvent signals that can overlap and obscure those of interest from the analyte. Here, two methods are proposed to suppress DNP solvent signals: a Forced Echo Dephasing experiment (FEDex) and TRAnsfer of Populations in DOuble Resonance Echo Dephasing (TRAPDORED) NMR...
May 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28363393/an-academic-practice-partnership-to-advance-dnp-education-and-practice
#16
Patricia B Howard, Tracy E Williams
During the past decade, the growth of doctor of nursing practice (DNP) programs in the United States has been phenomenal, with most focusing on the preparation of advanced practice registered nurses. Simultaneously, academic-practice partnerships have been a frequent subject of discussion for nursing's leading academic, administrative, and practice organizations. Numerous reports about academic-practice partnerships concerning aspects of baccalaureate nursing education exist, but partnership accounts for DNP programs are essentially nonexistent...
March 2017: Journal of Professional Nursing: Official Journal of the American Association of Colleges of Nursing
https://www.readbyqxmd.com/read/28359739/2-4-dnp-improves-motor-function-preserves-medium-spiny-neuronal-identity-and-reduces-oxidative-stress-in-a-mouse-model-of-huntington-s-disease
#17
Bin Wu, Mali Jiang, Qi Peng, Gang Li, Zhipeng Hou, Ginger L Milne, Susumu Mori, Robert Alonso, John G Geisler, Wenzhen Duan
Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the first exon of the gene huntingtin. There is no treatment to prevent or delay the disease course of HD currently. Oxidative stress and mitochondrial dysfunction have emerged as key determinants of the disease progression in HD. Therefore, counteracting mutant huntingtin (mHtt)-induced oxidative stress and mitochondrial dysfunction appears as a new approach to treat this devastating disease. Interestingly, mild mitochondrial uncoupling improves neuronal resistance to stress and facilitates neuronal survival...
March 28, 2017: Experimental Neurology
https://www.readbyqxmd.com/read/28352012/clinical-variables-differentiating-diabetic-from-nondiabetic-kidney-disease-in-patients-with-diabetes-a-single-center-study
#18
Salman Imtiaz, Beena Salman, Kiran Nasir, Murtaza F Drohlia, Aasim Ahmad
Patients with diabetes may have kidney diseases other than the diabetic kidney disease. Kidney biopsy is the investigation of choice when this is suspected. This retrospective analysis included all patients known to have diabetes mellitus (DM) and who had a kidney biopsy at our center between 1998 and 2014. The aim of this study was to assess if an association exists between the clinical factors on the presence or absence of diabetic nephropathy (DNP). A total number of 206 patients were included in our study...
March 2017: Saudi Journal of Kidney Diseases and Transplantation
https://www.readbyqxmd.com/read/28343015/systemic-delivery-of-the-tumor-necrosis-factor-gene-to-tumors-by-a-novel-dual-dna-nanocomplex-in-a-nanoparticle-system
#19
Vasundhara Shukla, Manu Dalela, Manika Vij, Munia Ganguli, Ralph Weichselbaum, Surender Kharbanda, Donald Kufe, Harpal Singh
Many cancers fail to respond to immunotherapy as a result of immune suppression by the tumor microenvironment. The exogenous expression of immune cytokines to reprogram the tumor microenvironment represents an approach to circumvent this suppression. The present studies describe the development of a novel dual nanoparticle (DNP) system for driving DNA expression vectors encoding inflammatory cytokines in tumor cells. The DNP system consists of a DNA expression vector-cationic nanocomplex (NC) surrounded by a diblock polymeric NP...
March 22, 2017: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/28333785/improving-decision-making-for-advanced-heart-failure-patients-and-caregivers
#20
Colleen K McIlvennan
In this month's Magnet® Perspectives column, Colleen K. McIlvennan, DNP, ANP, lead nurse practitioner, Advanced Heart Failure and Transplantation at the University of Colorado, discusses her groundbreaking research encompassing patients' and caregivers' emotional, rational, and fundamental beliefs when considering a left ventricular assist device (LVAD). Results have led to the development of 2 innovative decision aids that are currently in use by LVAD programs across the United States and Canada. Dr McIlvennan's efforts led to a $2 million grant from the Patient-Centered Outcomes Research Institute, as well as national recognition from the American Heart Association and the Heart Failure Society of America...
April 2017: Journal of Nursing Administration
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