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https://www.readbyqxmd.com/read/28103268/direct-observation-of-enhanced-nitric-oxide-in-a-murine-model-of-diabetic-nephropathy
#1
Margien G S Boels, Ernst E H van Faassen, M Cristina Avramut, Johan van der Vlag, Bernard M van den Berg, Ton J Rabelink
Uncoupling of nitric oxide synthase (NOS) secondary to redox signaling is a central mechanism in endothelial and macrophage activation. To date studies on the production of nitric oxide (NO) during the development of diabetic complications show paradoxical results. We previously showed that recoupling eNOS by increasing the eNOS cofactor tetrahydrobiopterin (BH4) could restore endothelial function and prevent kidney injury in experimental kidney transplantation. Here, we employed a diabetic mouse model to investigate the effects of diabetes on renal tissue NO bioavailability...
2017: PloS One
https://www.readbyqxmd.com/read/28103036/paramagnetic-enhancement-of-nuclear-spin-spin-coupling
#2
Peter John Cherry, Syed Awais Rouf, Juha Vaara
We present a derivation and computations of the paramagnetic enhancement of the nuclear magnetic resonance (NMR) spin-spin coupling, which may be expressed in terms of the hyperfine coupling (HFC) and (for systems with multiple unpaired electrons) zero-field splitting (ZFS) tensors. This enhancement is formally analogous to the hyperfine contributions to the NMR shielding tensor as formulated by Kurland and McGarvey. The significance of the spin-spin coupling enhancement is demonstrated by using a combination of density-functional theory and correlated ab initio calculations, to determine the HFC and ZFS tensors, respectively, for two paramagnetic 3d metallocenes, a Cr(II)(acac) 2 complex, a Co(II) pyrazolylborate complex, and a lanthanide system, Gd-DOTA...
January 19, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28101862/crystallographic-studies-of-intermediate-filament-proteins
#3
Dmytro Guzenko, Anastasia A Chernyatina, Sergei V Strelkov
Intermediate filaments (IFs), together with microtubules and actin microfilaments, are the three main cytoskeletal components in metazoan cells. IFs are formed by a distinct protein family, which is made up of 70 members in humans. Most IF proteins are tissue- or organelle-specific, which includes lamins, the IF proteins of the nucleus. The building block of IFs is an elongated dimer, which consists of a central α-helical 'rod' domain flanked by flexible N- and C-terminal domains. The conserved rod domain is the 'signature feature' of the IF family...
2017: Sub-cellular Biochemistry
https://www.readbyqxmd.com/read/28100006/the-fingerprint-of-antimitochondrial-antibodies-and-the-etiology-of-primary-biliary-cholangitis
#4
Zongwen Shuai, Jinjun Wang, Madhu Badamagunta, Jinjung Choi, Guoxiang Yang, Weici Zhang, Thomas P Kenny, Kathryn Guggenheim, Mark J Kurth, Aftab A Ansari, John Voss, Ross L Coppel, Pietro Invernizzi, Patrick S C Leung, M Eric Gershwin
The identification of environmental factors that lead to loss of tolerance has been coined the Holy Grail of autoimmunity. Our work has focused on the reactivity of antimitochondrial autoantibodies (AMA) to chemical xenobiotics and has hypothesized that a modified peptide within PDC-E2, the major mitochondrial autoantigen, will have been immunologically recognized at the time of loss of tolerance. Herein we successfully applied intein technology to construct a PDC-E2 protein fragment containing amino acid residues 177-314 of PDC-E2 by joining a recombinant peptide spanning residues 177 to 252 (PDC-228) with a 62 residue synthetic peptide from 253 to 314 (PP), which encompasses PDC-E2 ILD...
January 18, 2017: Hepatology: Official Journal of the American Association for the Study of Liver Diseases
https://www.readbyqxmd.com/read/28098983/redox-initiated-reactivity-of-dinuclear-%C3%AE-diketiminatoniobium-imido-complexes
#5
Benjamin M Kriegel, Lara C E Naested, Grégory Nocton, K V Lakshmi, Trevor D Lohrey, Robert G Bergman, John Arnold
High-valent dichloride and dimethylniobium complexes 1 and 2 bearing tert-butylimido and N,N'-bis(2,4,6-trimethylphenyl)-β-diketiminate (BDI(Ar)) ligands were prepared. The dimethyl complex reacted with dihydrogen to release methane and generate the hydride-bridged diniobium(IV) complex 3 in high yield. One-electron oxidation of 3 with silver salts resulted in the release of dihydrogen and conversion to a mixed-valent Nb(III)-Nb(IV) complex, 4, that displayed a frozen-solution X-band electron paramagnetic resonance signal consistent with a slight dissymmetry between the two Nb centers...
January 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28098798/free-radical-scavenging-activity-of-drops-and-spray-containing-propolis-an-epr-examination
#6
Pawel Olczyk, Katarzyna Komosinska-Vassev, Pawel Ramos, Lukasz Mencner, Krystyna Olczyk, Barbara Pilawa
The influence of heating at a temperature of 50 °C and UV-irradiation of propolis drops and spray on their free radical scavenging activity was determined. The kinetics of interactions of the propolis samples with DPPH free radicals was analyzed. Interactions of propolis drops and propolis spray with free radicals were examined by electron paramagnetic resonance spectroscopy. A spectrometer generating microwaves of 9.3 GHz frequency was used. The EPR spectra of the model DPPH free radicals were compared with the EPR spectra of DPPH in contact with the tested propolis samples...
January 13, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28098323/two-dimensional-melting-of-colloids-with-long-range-attractive-interactions
#7
Di Du, Manolis Doxastakis, Elaa Hilou, Sibani Lisa Biswal
The solid-liquid melting transition in a two-dimensional (2-D) attractive colloidal system is visualized using superparamagnetic colloids that interact through a long-range isotropic attractive interaction potential, which is induced using a high-frequency rotating magnetic field. Various experiments, supported by Monte Carlo simulations, are carried out over a range of interaction potentials and densities to determine structure factors, Lindermann parameters, and translational and orientational order parameters...
January 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28098314/isoindoline-nitroxide-labeled-porphyrins-as-potential-fluorescence-suppressed-spin-probes
#8
F Liu, T J Zou, Z L Tan, S Chen, Z H Wu, G P Yan, Q Zhang, S C Liang, J Yang
A series of isoindoline nitroxide-labeled porphyrins were synthesized by the reaction of 5-phenyldipyrromethane and 5-(4'-carboethoxy-methyleneoxyphenyl)dipyrromethane with 5-formyl-1,1,3,3-tetramethylisoindolin-2-yloxyl (FTMIO) using the Lindsey method. The corresponding water-soluble spin-labeled porphyrins were also prepared. Subsequently, these compounds were characterized and their in vitro properties were evaluated. The electrochemical assay demonstrated that these isoindoline nitroxide-labeled porphyrins had similar electrochemical and redox properties to 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (CTMIO)...
January 18, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28097861/light-driven-au-wo3-c-janus-micromotors-for-rapid-photodegradation-of-dye-pollutants
#9
Qilu Zhang, Renfeng Dong, Yefei Wu, Wei Gao, Zihan He, Biye Ren
A novel light-driven Au-WO3@C Janus micromotor based on colloidal carbon WO3 nanoparticle composite spheres (WO3@C) prepared by one-step hydrothermal treatment is described. The Janus micromotors can move in aqueous media at a speed of 16 μm/s under 40 mW/cm2 UV light due to diffusiophoretic effects. The propulsion of such Au-WO3@C Janus micromotors (diameter ~1.0 μm) can be generated by UV light in pure water without any external chemical fuels and readily modulated by light intensity. After depositing a paramagnetic Ni layer between Au layer and WO3, the motion direction of the micromotor can be precisely controlled by an external magnetic field...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28094930/fe-and-ln-dotam-f12-are-effective-paramagnetic-fluorine-contrast-agents-for-mri-in-water-and-blood
#10
Kriti Srivastava, Evan A Weitz, Katie L Peterson, Małgorzata Marjańska, Valérie C Pierre
A series of fluorinated macrocyclic complexes, M-DOTAm-F12, where M is La(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III), and Fe(II), was synthesized, and their potential as fluorine magnetic resonance imaging (MRI) contrast agents was evaluated. The high water solubility of these complexes and the presence of a single fluorine NMR signal, two necessary parameters for in vivo MRI, are substantial advantages over currently used organic polyfluorocarbons and other reported paramagnetic (19)F probes...
January 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28094521/titanium-iii-member-of-the-family-of-trigonal-building-blocks-with-scorpionate-and-cyanide-ligands
#11
Andrew Brown, Mohamed Saber, Willem Van den Heuvel, Kelsey Schulte, Alessandro Soncini, Kim R Dunbar
The titanium(III) cyanide compound [Et4N][Tp*Ti(CN)3] ([Et4N] = tetraethylamonium; Tp* = 3,5-dimethyltrispyrazolylhydroborate) is reported, which exhibits a trigonally distorted geometry. Magnetic data and ab initio calculations verified that the molecule is an S = (1)/2 paramagnet and that it exhibits significant temperature-independent paramagnetism.
January 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28094367/formation-of-carbon-nanodots-with-different-spin-states-in-mechanically-processed-mixtures-of-zno-with-carbon-nanoparticles-an-electron-paramagnetic-resonance-study
#12
M Kakazey, M Vlasova, V Gómez-Vidales, A Ángeles-Pascual, V A Basiuk
Mixtures of zinc oxide with carbon nanoparticles, ZnO + xC (x = 0.1%, 1% and 3% by weight), were subjected to mechanical processing (MP) in a hermetically sealed grinding chamber. Using electron paramagnetic resonance (EPR) spectroscopy, we monitored the evolution of spin centers in CNPs. While the initial CNPs were EPR silent, their short-duration MP (tMP) gave rise to emergence of low-intensity carbon signal. Increasing the sample temperature at tMP > 9 min induced CNP oxidation, which lead to a dramatic increase in the intensity of C signal...
January 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28094364/effect-of-electron-spectral-diffusion-on-static-dynamic-nuclear-polarization-at-7-tesla
#13
Alisa Leavesley, Daphna Shimon, Ting Ann Siaw, Akiva Feintuch, Daniella Goldfarb, Shimon Vega, Ilia Kaminker, Songi Han
Here, we present an integrated experimental and theoretical study of (1)H dynamic nuclear polarization (DNP) of a frozen aqueous glass containing free radicals at 7 T, under static conditions and at temperatures ranging between 4 and 20 K. The DNP studies were performed with a home-built 200 GHz quasi-optics microwave bridge, powered by a tunable solid-state diode source. DNP using monochromatic and continuous wave (cw) irradiation applied to the electron paramagnetic resonance (EPR) spectrum of the radicals induces the transfer of polarization from the electron spins to the surrounding nuclei of the solvent and solutes in the frozen aqueous glass...
January 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28093899/crucial-role-of-donor-density-in-the-performance-of-oxynitride-perovskite-latio2n-for-photocatalytic-water-oxidation-reaction
#14
Feng-Qiang Xiong, Lipeng Wan, Yue Li, Tiju Thomas, Francis Joseph DiSalvo, Minghui Yang
LaTiO2N photocatalysts were prepared via thermal ammonalysis of flux-synthesized La2Ti2O7 and La2TiO5, and were investigated for water oxidation. Though LaTiO2N derived from La2TiO5 appears defect-free in UV-Vis-NIR and electron paramagnetic resonance spectroscopies, its performance is much lower than conventional La2Ti2O7-derived LaTiO2N with defects. It is shown by Mott-Schottky analysis that La2TiO5-derived LaTiO2N has significantly lower donor density; this can result in insufficient build-in electric field for the separation of photogenerated electrons and holes...
January 17, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28092786/imaging-thiol-redox-status-in-murine-tumors-in-vivo-with-rapid-scan-electron-paramagnetic-resonance
#15
Boris Epel, Subramanian V Sundramoorthy, Martyna Krzykawska-Serda, Matthew C Maggio, Mark Tseytlin, Gareth R Eaton, Sandra S Eaton, Gerald M Rosen, Joseph P Y Kao, Howard J Halpern
Thiol redox status is an important physiologic parameter that affects the success or failure of cancer treatment. Rapid scan electron paramagnetic resonance (RS EPR) is a novel technique that has shown higher signal-to-noise ratio than conventional continuous-wave EPR in in vitro studies. Here we used RS EPR to acquire rapid three-dimensional images of the thiol redox status of tumors in living mice. This work presents, for the first time, in vivo RS EPR images of the kinetics of the reaction of (2)H,(15)N-substituted disulfide-linked dinitroxide (PxSSPx) spin probe with intracellular glutathione...
December 31, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28091928/effects-of-no-synthase-blocker-l-name-on-functional-state-of-the-neuromotor-system-during-traumatic-disease-of-the-spinal-cord
#16
G G Yafarova, V V Andrianov, R Kh Yagudin, I I Shaikhytdinov, Kh L Gainutdinov
Functional state of the neuromotor system after administration of a nonspecific NO synthase blocker L-NAME was studied on the model of experimental contusion of the spinal cord. Electron paramagnetic resonance measurements of NO production in the damaged segment of the spinal cord were performed for estimation of the dynamics of intensity of NO production during traumatic disease of the spinal cord and selection of optimal period for L-NAME administration. The status of the neuromotor system was evaluated by stimulation electromyography...
January 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28087449/highly-biocompatible-chitosan-with-super-paramagnetic-calcium-ferrite-cafe2o4-nanoparticle-for-the-release-of-ampicillin
#17
Ram Bilas, K Sriram, P Uma Maheswari, K M Meera Sheriffa Begum
The CaFe2O4 nanoparticles (CFNP) were synthesized using the solution combustion method. The CFNP-chitosan-ampicillin was prepared by the ionic gelation method using tripolyphosphate (TPP). The CFNP, chitosan-CFNP, chitosan-CFNP-ampicillin materials were characterized by XRD, FT-IR and TGA analysis in order to evaluate the particle nature and size, the presence of functional groups and their thermal stability. The FESEM and EDAX analysis were performed to understand the surface morphology of the materials and the presence of CFNP in the material, respectively...
January 10, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28081476/electron-spin-relaxation-of-a-boron-containing-heterocyclic-radical
#18
Sandra S Eaton, Kirby Huber, Hanan Elajaili, Joseph McPeak, Gareth R Eaton, Lauren E Longobardi, Douglas W Stephan
Preparation of the stable boron-containing heterocyclic phenanthrenedione radical, (C6F5)2B(O2C14H8), by frustrated Lewis pair chemistry has been reported recently. Electron paramagnetic resonance measurements of this radical were made at X-band in toluene:dichloromethane (9:1) from 10 to 293K, in toluene from 180 to 293K and at Q-band at 80K. In well-deoxygenated 0.1mM toluene solution at room temperature hyperfine splittings from (11)B, four pairs of (1)H, and 5 pairs of (19)F contribute to an EPR spectrum with many resolved lines...
December 30, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28081012/the-lead-acceptor-in-p-type-natural-2h-polytype-mos2-crystals-evidenced-by-electron-paramagnetic-resonance
#19
S Iacovo, A Stesmans, M Houssa, V V Afanas'ev
A low-temperature (T  =  1.5-8 K) electron paramagnetic resonance study of p-type 2H-polytype natural MoS2 crystals reveals a previously unreported anisotropic signal of corresponding defect density (spin S  =  ½) ~5  ×  10(14) cm(-3). For the applied magnetic field B//c-axis, the response is comprised of a single central asymmetric Zeeman peak at zero-crossing g  =  2.102(1), amid a symmetrically positioned hyperfine doublet of splitting 6.6(2) G. Field angular observations reveal a two-branch g pattern, indicative of a defect of lower than axial symmetry, likely orthorhombic (C 2v)...
January 12, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28078892/dynamical-transitions-at-low-temperatures-in-the-nearest-hydration-shell-of-phospholipid-bilayers
#20
Victoria N Syryamina, Sergei Andreevich Dzuba
For the so-called dynamical transition from harmonic to anharmonic (or diffusive) motions in biological systems, the presence of hydration water is important. To explain the molecular mechanism of this transition, the information on molecular motions in the nearest hydration shell would be helpful. In this work, to study molecular motions in the nearest hydration shell of spin-labeled model biological membranes, a pulsed version of electron paramagnetic resonance (EPR)-electron spin echo envelope modulation (ESEEM) spectroscopy-is employed...
January 12, 2017: Journal of Physical Chemistry. B
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